PUBLICATIONS
Piga, A, FontPomarol, L, SalesPardo, M, Guimerà, R.
Chaos, Solitons & Fractals
180
,
114564
(2024).
Estimating the Shannon entropy of a discrete distribution from which we have only observed a small sample is challenging. Estimating other informationtheoretic metrics, such as the Kullback–Leibler divergence between two sparsely sampled discrete distributions, is even harder. Here, we propose a fast, semianalytical estimator for sparsely sampled distributions. Its derivation
...
SalesPardo, M, MarinéTena, A, Guimerà, R.
Proc. Natl. Acad. Sci. USA
120 (50)
,
e2303887120
(2023).
Complex networked systems often exhibit higherorder interactions, beyond dyadic interactions, which can dramatically alter their observed behavior. Consequently, understanding hypergraphs from a structural perspective has become increasingly important. Statistical, groupbased inference approaches are well suited for unveiling the underlying community structure and predicting unobserved interactions. However, these approaches often rely
...
Krauss, A, Danús, L, SalesPardo, M.
Sci. Rep.
13
,
art. no. 18794
(2023).
Can we help predict the future impact of researchers using earlycareer factors? We analyze earlycareer factors of the world’s 100 most prominent researchers across 8 scientific fields and identify four key drivers in researchers’ initial career: working at a top 25 ranked university, publishing a paper in a top 5
...
Danús, Ll, Muntaner, C, Krauss, A, SalesPardo, M, Guimerà, R
.
EPJ Data Sci.
12
,
art. no. 12
(2023).
Scientists collaborate through intricate networks, which impact the quality and scope of their research. At the same time, funding and institutional arrangements, as well as scientific and political cultures, affect the structure of collaboration networks. Since such arrangements and cultures differ across regions in the world in systematic ways, we
...
FajardoFontiveros, O, Reichardt, I, De Los Ríos, HR, Duch, J, SalesPardo, M, Guimerà, R.
Nat. Comm.
14
,
1043
(2023).
Given a finite and noisy dataset generated with a closedform mathematical model, when is it possible to learn the true generating model from the data alone? This is the question we investigate here. We show that this modellearning problem displays a transition from a lownoise phase in which the true
...
FontPomarol, Ll, Piga, A, GarciaTeruel, RM, NasarreAznar, S, SalesPardo, M, Guimera, R .
EPJ Data Sci.
12
,
art. no. 2
(2023).
Laws and legal decisionmaking regulate how societies function. Therefore, they evolve and adapt to new social paradigms and reflect changes in culture and social norms, and are a good proxy for the evolution of socially sensitive issues. Here, we use an informationtheoretic methodology to quantitatively track trends and shifts in
...
Bianconi, G, et al..
J. Phys. Complex.
4
,
010201
(2023).
The 2021 Nobel Prize in Physics recognized the fundamental role of complex systems in the natural sciences. In order to celebrate this milestone, this editorial presents the point of view of the editorial board of JPhys Complexity on the achievements, challenges, and future prospects of the field. To distinguish the
...
Negri, V, Vázquez, D, SalesPardo, M, Guimera, R, GuillénGosálbez, G.
ACS Omega
7 (45)
,
41147
41164
(2022).
Process modeling has become a fundamental tool to guide experimental work. Unfortunately, process models based on first principles can be expensive to develop and evaluate, and hard to use, particularly when convergence issues arise. This work proves that Bayesian symbolic learning can be applied to derive simple closedform expressions from
...
GonzalezFranquesa, A, GamaPerez, P, et al.
Redox Biol.
54
,
102353
(2022).
Metabolic plasticity is the ability of a biological system to adapt its metabolic phenotype to different environmental stressors. We used a wholebody and tissuespecific phenotypic, functional, proteomic, metabolomic and transcriptomic approach to systematically assess metabolic plasticity in dietinduced obese mice after a combined nutritional and exercise intervention. Although most obesity
...
CoboLópez, S, Gupta, VK, Sung, J, Guimerà, R, SalesPardo, M.
PNAS Nexus
1 (3)
,
pgac055
(2022).
A key question in human gut microbiome research is what are the robust structural patterns underlying its taxonomic composition. Herein, we use whole metagenomic datasets from healthy human guts to show that such robust patterns do exist, albeit not in the conventional enterotype sense. We first introduce the concept of
...
Suriyalaksh, M, Raimondi, C, Mains, A, SegondsPichon, A, Mukhtar, S, Murdoch, S, Aldunate, R, Krueger, F, Guimerà, R, Andrews, S, M. SalesPardo, M, Casanueva, O.
iScience
25 (1)
,
103663
(2022).
We design a “wisdomofthecrowds” GRN inference pipeline, and couple it to complex network analysis, to understand the organisational principles governing gene regulation in longlived glp1/Notch C. elegans. The GRN has three layers (input, core, output) and is topologically equivalent to bowtie/hourglass structures prevalent among metabolic networks. To assess the functional
...
FajardoFontiveros, O, Guimerà, R, SalesPardo, M.
Phys. Rev. X
12
,
011010
(2022).
Network inference is the process of learning the properties of complex networks from data. Besides using information about known links in the network, node attributes and other forms of network metadata can help solve network inference problems. Indeed, several approaches have been proposed to introduce metadata into probabilistic network models
...
Vázquez, D, Guimerà, R, SalesPardo, M, GuillénGosálbez, G.
Sustain. Prod. Consum.
30
,
596
607
(2022).
Predicting countries’ energy consumption and pollution levels precisely from socioeconomic drivers will be essential to support sustainable policymaking in an effective manner. Current predictive models, like the widely used STIRPAT equation, are based on rigid mathematical expressions that assume constant elasticities. Using a Bayesian approach to symbolic regression, here we
...
PouxMédard, G, CoboLopez, S, Duch, J, Guimerà, R, SalesPardo, M.
EPJ Data Sci.
10
,
26
(2021).
Many studies have shown that there are regularities in the way human beings make decisions. However, our ability to obtain models that capture such regularities and can accurately predict unobserved decisions is still limited. We tackle this problem in the context of individuals who are given information relative to the
...
RodríguezMartínez, X, PascualSanJosé, E, Fei, Z, Heeney, M, Guimerà, R, CampoyQuiles, M.
Energy Environ. Sci.
14
,
986
(2021).
The continuous development of improved nonfullerene acceptors and deeper knowledge of the fundamental mechanisms governing performance underpin the vertiginous increase in efficiency witnessed by organic photovoltaics. While the influence of parameters like film thickness and morphology are generally understood, what determines the strong dependence of the photocurrent on the donor
...
Guimera, R.
Proc. Natl. Acad. Sci. USA
117 (41)
,
2519525197
(2020).
In a way, it seems, progress in network science is about finding free lunches—model families that can express the features of realworld networks, that we can explore systematically, and that we can refine as new patterns are uncovered to improve their predictive performance.
...
Pozo, C, GalanMartin, A, CortesBorda, D, SalesPardo, M, Azapagic, A, Guimera, R, GuillenGosalbez, G.
Journal of Cleaner Production
270
,
121828
(2020).
Reducing inequality is essential for sustainable development, yet our understanding of its many dimensions and driving forces is still limited. Here we study the global distribution of 25 environmental burdens encompassing natural resources (water, materials and land use) and air emissions, all related to activities underpinning human welfare. We find
...
Reichardt, I, Pallarès, J, SalesPardo, M, Guimerà, R.
Phys. Rev. Lett.
124
,
084503
(2020).
Ever since Nikuradse’s experiments on turbulent friction in 1933, there have been theoretical attempts to describe his measurements by collapsing the data into singlevariable functions. However, this approach, which is common in other areas of physics and in other fields, is limited by the lack of rigorous quantitative methods to
...
Guimera, R, Reichardt, I, AguilarMogas, A, Massucci, FA, Miranda, M, Pallares, J, SalesPardo, M.
Sci. Adv.
6 (5)
,
eaav6971
(2020).
Closedform, interpretable mathematical models have been instrumental for advancing our understanding of the world; with the data revolution, we may now be in a position to uncover new such models for many systems from physics to the social sciences. However, to deal with increasing amounts of data, we need “machine
...
Senan, O, AguilarMogas, A, Navarro, M, Capellades, J, Noon, L, Burks, D, Yanes, O, Guimerà, R, SalesPardo, M.
Bioinformatics
35 (20)
,
4089
4097
(2019).
The analysis of biological samples in untargeted metabolomic studies using LCMS yields tens of thousands of ion signals. Annotating these features is of the utmost importance for answering questions as fundamental as, e.g. how many metabolites are there in a given sample. Here, we introduce CliqueMS, a new algorithm for
...
Menden, MP, Wang, D, […] SaezRodriguez, J.
Nat. Comm.
10
,
Art, num. 2674
(2019).
The effectiveness of most cancer targeted therapies is shortlived. Tumors often develop resistance that might be overcome with drug combinations. However, the number of possible combinations is vast, necessitating datadriven approaches to find optimal patientspecific treatments. Here we report AstraZeneca’s large drug combination dataset, consisting of 11,576 experiments from 910
...
GodoyLorite A., Guimerà R., SalesPardo M.
In: Moscato P., de Vries N. (eds) Business and Consumer Analytics: New Ideas. Springer, Cham
,
(2019).
With the overwhelming online products available in recent years, there is an increasing need to filter and deliver relevant personalized advice for users. Recommender systems solve this problem by modelling and predicting individual preferences for a great variety of items such as movies, books or research articles. In this chapter,
...
TarrésDeulofeu, M, GodoyLorite, A, Guimerà, R, SalesPardo, M
.
Phys. Rev. E
99
,
032307
(2019).
Many realworld complex systems are well represented as multilayer networks; predicting interactions in those systems is one of the most pressing problems in predictive network science. To address this challenge, we introduce two stochastic block models for multilayer and temporal networks; one of them uses nodes as its fundamental unit,
...
CoboLópez, S, GodoyLorite, A, Duch, J, SalesPardo, M, Guimerà, R.
EPJ Data Sci.
7
,
48
(2018).
Advancing our understanding of human behavior hinges on the ability of theories to unveil the mechanisms underlying such behaviors. Measuring the ability of theories and models to predict unobserved behaviors provides a principled method to evaluate their merit and, thus, to help establish which mechanisms are most plausible. Here, we
...
GarciaAlgar, M, FernandezCarrascal, A, OlanoDaza, A, Guerrini, L, Feliu, N, Parak, WJ, Guimera, R, Eduardo GarciaRico, E, AlvarezPuebla, RA.
npj Precision Oncology
2
,
art. no. 16
(2018).
In this manuscript, we demonstrate the applicability of a metabolic liquid biopsy for the monitoring and staging of patients with lung cancer. This method provides an unbiased detection strategy to establish a more precise correlation between CTC quantification and the actual burden of disease, therefore improving the accuracy of staging
...
Niven, RK, Schlegel, M, Abel, M, Waldrip, SH, Guimera R.
Springer Proceedings in Mathematics & Statistics
,
vol. 239, 261274
(2018).
This study examines MaxEnt methods for probabilistic inference of the state of flow networks, including pipe flow, electrical and transport networks, subject to physical laws and observed moments. While these typically assume networks of invariant graph structure, we here consider higherlevel MaxEnt schemes, in which the network structure constitutes part
...
VallesCatala, T, Peixoto TP, SalesPardo, M, Guimera, R
.
Phys. Rev. E
97
,
062316
(2018).
A principled approach to understand network structures is to formulate generative models. Given a collection of models, however, an outstanding key task is to determine which one provides a more accurate description of the network at hand, discounting statistical fluctuations. This problem can be approached using two principled criteria that
...
Uroz, M, Wistorf, S, SerraPicamal, X, Conte, V, SalesPardo, M, RocaCusachs, P, Guimera, R, Trepat, X.
Nat. Cell Biol.
20
,
646
654
(2018).
It has long been proposed that the cell cycle is regulated by physical forces at the cell–cell and cell–extracellular matrix (ECM) interfaces. However, the evolution of these forces during the cycle has never been measured in a tissue, and whether this evolution affects cell cycle progression is unknown. Here, we
...
RoviraAsenjo, R, Pietraszkiewicz, A, Sczesny, S, Gumi, T, Guimera, R, SalesPardo, M.
PLoS ONE
12 (10)
,
e0186045
(2017).
Leadership positions are still stereotyped as masculine, especially in maledominated fields (e.g., engineering). So how do gender stereotypes affect the evaluation of leaders and team cohesiveness in the process of team development? In our study participants worked in 45 small teams (4–5 members). Each team was headed by either a female or male
...
SalesPardo, M.
Science
357 (6347)
,
128
129
(2017).
In the 1970s, ecologists began to speculate that modular systems—which are organized into blocks or modules—can better contain perturbations and are therefore more resilient against external damage (1). This simple concept can be applied to any networked system, be it an ecosystem, cellular metabolism, traffic flows, human disease contagion, a
...
EsteveAltava, B, VallesCatala, T, Guimera, R, SalesPardo, M, RasskinGutman, D.
Sci. Rep.
7
,
art. no. 3376
(2017).
Craniosynostosis, the premature fusion of cranial bones, affects the correct development of the skull producing morphological malformations in newborns. To assess the susceptibility of each craniofacial articulation to close prematurely, we used a network model of the skull to quantify the link reliability (an index based on stochastic block models
...
AguilarMogas, A, SalesPardo, M, Navarro, M, Guimerà, R, Yanes, O.
Anal. Chem.
89 (6)
,
3474
3482
(2017).
Structural annotation of metabolites relies mainly on tandem mass spectrometry (MS/MS) analysis. However, approximately 90% of the known metabolites reported in metabolomic databases do not have annotated spectral data from standards. This situation has fostered the development of computational tools that predict fragmentation patterns in silico and compare these to
...
Cobo, S, Ahn, F, Eremin, I, Akbari, A.
Phys. Rev. B
94
,
224507
(2016).
We analyze the spin anisotropy of the magnetic susceptibility of Sr2RuO4 in the presence of spinorbit coupling and anisotropic strain using quasitwodimensional tightbinding parametrization fitted to the angleresolved photoemission spectroscopy results. Similar to the previous observations we find the inplane polarization of the lowq magnetic fluctuations and the outofplane polarization
...
GodoyLorite, A, Guimera, R, Moore, C, SalesPardo, M.
Proc. Natl. Acad. Sci. USA
113 (50)
,
14207
14212
(2016).
Recommendation systems are designed to predict users’ preferences and provide them with recommendations for items such as books or movies that suit their needs. Recent developments show that some probabilistic models for user preferences yield better predictions than latent feature models such as matrix factorization. However, it has not been
...
Zeng, XHT, Duch, J, SalesPardo, M, Moreira, JAG, Radicchi, F, Ribeiro, HV, Woodruff, TK, Amaral, LAN .
PLoS Biol.
14(11)
,
e1002573
(2016).
Collaboration plays an increasingly important role in promoting research productivity and impact. What remains unclear is whether female and male researchers in science, technology, engineering, and mathematical (STEM) disciplines differ in their collaboration propensity. Here, we report on an empirical analysis of the complete publication records of 3,980 faculty members
...
Massucci, FA, Wheeler, J, BeltranDebon, R, Joven, J, SalesPardo, M, Guimera, R.
Sci. Adv.
2
,
e1501638
(2016).
In a complex system, perturbations propagate by following paths on the network of interactions among the system’s units. In contrast to what happens with the spreading of epidemics, observations of general perturbations are often very sparse in time (there is a single observation of the perturbed system) and in “space”
...
VallesCatala, T, Massucci, FA, Guimera, R, SalesPardo, M.
Phys. Rev. X
6
,
011036
(2016).
In complex systems, the network of interactions we observe between systems components is the aggregate of the interactions that occur through different mechanisms or layers. Recent studies reveal that the existence of multiple interaction layers can have a dramatic impact in the dynamical processes occurring on these systems. However, these
...
GodoyLorite, A, Guimera, R , SalesPardo, M.
PLOS ONE
11(1)
,
e0146113
(2016).
In social networks, individuals constantly drop ties and replace them by new ones in a highly unpredictable fashion. This highly dynamical nature of social ties has important implications for processes such as the spread of information or of epidemics. Several studies have demonstrated the influence of a number of factors
...
Guimera, R, SalesPardo, M.
Rev. SEBBM
186
,
14
16
(2015).
Nuevos enfoques nos permiten avanzar en la definición de un nuevo concepto de ruta metabólica, más general y mejor sustentado en la realidad sistémica del metabolismo. Pero todavía se tienen que desarrollar los métodos específicos que permitan extraer significado biológico a partir de la información disponible hoy.
...
Pallares, J, Senan, O, Guimera, R, Vernet, A, AguilarMogas, A, Vilahur, G, Badimon, L, SalesPardo, M, Cito, S.
Sci. Rep.
5
,
13606
(2015).
Thrombus formation is a multiscale phenomenon triggered by platelet deposition over a protrombotic surface (eg. a ruptured atherosclerotic plaque). Despite the medical urgency for computational tools that aid in the early diagnosis of thrombotic events, the integration of computational models of thrombus formation at different scales requires a comprehensive understanding
...
Güell, O, Massucci, FA, FontClos, F, Sagués, F, Serrano MÁ.
J. R. Soc. Interface
12
,
20150543
(2015).
Experimental and empirical observations on cell metabolism cannot be understood as a whole without their integration into a consistent systematic framework. However, the characterization of metabolic flux phenotypes is typically reduced to the study of a single optimal state, such as maximum biomass yield that is by far the most
...
MeoEvoli, N, Almacellas E, Massucci FA, Gentilella A, Ambrosio S, Kozma SC, Thomas G, Tauler A.
Oncotarget
5
,

(2015).
In addition to being a master regulator of cell cycle progression, E2F1 regulates other associated biological processes, including growth and malignancy. Here, we uncover a regulatory network linking E2F1 to lysosomal trafficking and mTORC1 signaling that involves vATPase regulation. By immunofluorescence and timelapse microscopy we found that E2F1 induces the
...
BeltranDebon, R, RodriguezGallego, E, FernandezArroyo, S, SenanCampos, O, Massucci, FA, HernandezAguilera, A, SalesPardo, M, Guimera, R, Camps, J, Menendez, JA, Joven, J.
Food Funct.
6
,
2957
2966
(2015).
We explored the acute multifunctional effects of polyphenols from Hibiscus sabdariffa in humans to assess possible consequences on the host's health. The expected dynamic response was studied using a combination of transcriptomics and metabolomics to integrate specific functional pathways through networkbased methods and to generate hypotheses established by acute metabolic
...
Massucci, FA, Guimera, R, Amaral, LAN, SalesPardo, M.
Phys. Rev. E
91
,
062703
(2015).
Highthroughput experimental techniques and bioinformatics tools make it possible to obtain reconstructions of the metabolism of microbial species. Combined with mathematical frameworks such as flux balance analysis, which assumes that nutrients are used so as to maximize growth, these reconstructions enable us to predict microbial growth. Although such predictions are
...
Bazellieres, E, Conte, V, EloseguiArtola, A, SerraPicamal, X, BintanelMorcillo, M, RocaCusachs, P, Muñoz, JJ, SalesPardo, M, Guimera, R, Trepat, T.
Nat. Cell Biol.
17
,
409
420
(2015).
Dynamics of epithelial tissues determine key processes in development, tissue healing and cancer invasion. These processes are critically influenced by cell–cell adhesion forces. However, the identity of the proteins that resist and transmit forces at cell–cell junctions remains unclear, and how these proteins control tissue dynamics is largely unknown. Here
...
Sirer, MI, Maroulis, S, Guimera, R, Wilensky, U, Amaral, LAN.
J. Policy Anal. Manag
34 (2)
,
358
377
(2015).
Existing research highlights that families face geographic, social, and psychological constraints that may limit the extent to which competition can take hold in school choice programs. In this paper, we address the implications of such findings by creating a network of student flows from 11 cohorts of eighthgrade students in
...
CortesBorda, D, RuizHernandez, A, GuillénGosalbez, G, Llop, M, Guimera, R, SalesPardo, M
.
Energ. Policy
77
,
21
30
(2015).
Global warming mitigation has recently become a priority worldwide. A large body of literature dealing with energy related problems has focused on reducing greenhouse gases emissions at an engineering scale. In contrast, the minimization of climate change at a wider macroeconomic level has so far received much less attention. We
...
GavaldaMiralles, A, Otto, JS, Bustamanate, FE, Amaral, LAN, Duch, J, Guimera, R.
CoNEXT '14 Proceedings of the 10th ACM International Conference on emerging Networking Experiments and Technologies
,
319
324
(2014).
Though the impact of filesharing of copyrighted content has been discussed for over a decade, only in the past few years have countries begun to adopt legislation to criminalize this behavior. These laws impose penalties ranging from warnings and monetary fines to disconnecting Internet service. While their supporters are quick
...
Massucci, FA, Pérez Castillo, I, Pérez Vicente, CJ.
Phys. Rev. E
90
,
052708
(2014).
The mechanical properties of molecules are today captured by single molecule manipulation experiments, so that polymer features are tested at a nanometric scale. Yet devising mathematical models to get further insight beyond the commonly studied forceelongation relation is typically hard. Here we draw from techniques developed in the context of
...
GavaldaMiralles, A, Choffnes, DR, Otto, JS, Sanchez, MA, Bustamante, FE, Amaral, LAN, Duch, J, Guimera, R.
Proc. Natl. Acad. Sci. U. S. A.
111 (43)
,
15322
15327
(2014).
Tens of millions of individuals around the world use decentralized content distribution systems, a fact of growing social, economic, and technological importance. These sharing systems are poorly understood because, unlike in other technosocial systems, it is difficult to gather largescale data about user behavior. Here, we investigate user activity patterns
...
Li, GP, Li, M, Zhang, YW, Wang, D, Li, R, Guimera, R, Gao, JT, Zhang, MQ.
PLOS ONE
9 (5)
,
e94608
(2014).
Rapidly increasing amounts of (physical and genetic) proteinprotein interaction (PPI) data are produced by various highthroughput techniques, and interpretation of these data remains a major challenge. In order to gain insight into the organization and structure of the resultant large complex networks formed by interacting molecules, using simulated annealing, a
...
Guimera, R, SalesPardo, M.
PLOS Comput. Biol.
9 (12)
,
e1003374
(2013).
Characterizing interactions between drugs is important to avoid potentially harmful combinations, to reduce offtarget effects of treatments and to fight antibiotic resistant pathogens, among others. Here we present a network inference algorithm to predict uncharacterized drugdrug interactions. Our algorithm takes, as its only input, sets of previously reported interactions, and
...
Massucci, FA, DiNuzzo, M, Giove, F, Maraviglia, B, Pérez Castillo, I, Marinari, E, De Martino, A.
.
BMC Systems Biology
7
,
103
(2013).
Background: The energetics of cerebral activity critically relies on the functional and metabolic interactions between neurons and astrocytes. Important open questions include the relation between neuronal versus astrocytic energy demand, glucose uptake and intercellular lactate transfer, as well as their dependence on the level of activity.
Results: We have developed a...
Capitan, JA, Arenas, A, Guimera, R.
J. Theor. Biol.
334
,
35
44
(2013).
In food webs, the degree of intervality of consumers' diets is an indicator of the number of dimensions that are necessary to determine the niche of a species. Previous studies modeling foodweb structure have shown that real networks are compatible with a high degree of diet contiguity. However, current models
...
Massucci FA, FontClos F, De Martino A, Pérez Castillo I..
Metabolites
2013
,
838852
(2013).
Quite generally, constraintbased metabolic flux analysis describes the space of viable flux configurations for a metabolic network as a highdimensional polytope defined by the linear constraints that enforce the balancing of production and consumption fluxes for each chemical species in the system. In some cases, the complexity of the solution
...
RoviraAsenjo, N, Gumi, T, SalesPardo, M, Guimera, R.
Sci. Rep.
3
,
art. no. 1999
(2013).
Despite the welldocumented benefits of working in teams, teamwork also results in communication, coordination and management costs, and may lead to personal conflict between team members. In a context where teams play an increasingly important role, it is of major importance to understand conflict and to develop diagnostic tools to
...
SalesPardo, M, Diermeier, D, Amaral, LAN.
PLOS ONE
8 (5)
,
e58989
(2013).
Social groups of interacting agents display an ability to coordinate in the absence of a central authority, a phenomenon that has been recently amplified by the widespread availability of social networking technologies. Models of opinion formation in a population of agents have proven a very useful tool to investigate these
...
Pah, AR, Guimera, R, Mustoe, AM, Amaral, LAN.
Sci. Rep.
3
,
art. no. 1695
(2013).
The difficulty in annotating the vast amounts of biological information poses one of the greatest current challenges in biological research. The number of genomic, proteomic, and metabolomic datasets has increased dramatically over the last two decades, far outstripping the pace of curation efforts. Here, we tackle the challenge of curating
...
Duch, J, Zeng, XHT, SalesPardo, M, Radicchi, F, Otis, S, Woodruff, TK, Amaral, LAN.
PLOS ONE
,
7(12): e51332
(2012).
Many studies demonstrate that there is still a significant gender bias, especially at higher career levels, in many areas including science, technology, engineering, and mathematics (STEM). We investigated fielddependent, genderspecific effects of the selective pressures individuals experience as they pursue a career in academia within seven STEM disciplines. We built
...
Seaver, SMD, SalesPardo, M, Guimera, R, Amaral, LAN.
PLOS Comput. Bio.
,
8(11): e1002762
(2012).
The ability of microbial species to consume compounds found in the environment to generate commerciallyvaluable products has long been exploited by humanity. The untapped, staggering diversity of microbial organisms offers a wealth of potential resources for tackling medical, environmental, and energy challenges. Understanding microbial metabolism will be crucial to many
...
FontClos, F, Massucci, FA, Pérez Castillo I.
J. Stat. Mech.Theory Exp.
,
P11003
(2012).
In this work we introduce a novel weighted messagepassing algorithm based on the cavity method for estimating volumerelated properties of random polytopes, properties which are relevant in various research fields ranging from metabolic networks, to neural networks, to compressed sensing. We propose, as opposed to adopting the usual approach consisting
...
Guimera, R.
Front. Gene.
3
,
183
(2012).
A book review on "Networks: an introduction"
...
Guimera, R, Llorente, A, Moro, E, SalesPardo, M.
PLOS ONE
7 (9)
,
e44620
(2012).
With everincreasing available data, predicting individuals' preferences and helping them locate the most relevant information has become a pressing need. Understanding and predicting preferences is also important from a fundamental point of view, as part of what has been called a ?new? computational social science. Here, we propose a novel
...
Stouffer, DB, SalesPardo, M, Sirer, MI, Bascompte, J.
Science
335
,
1489
1492
(2012).
Studies of ecological networks (the web of interactions between species in a community) demonstrate an intricate link between a community?s structure and its longterm viability. It remains unclear, however, how much a community?s persistence depends on the identities of the species present, or how much the role played by each
...
N. RoviraAsenjo, S. Ozgen, M. Medir, J. Tous, J. R. Alabart.
The Spanish journal of psychology
15
,
216
226
(2012).
The selection process of team leaders is fundamental if the effectiveness of teams is to be guaranteed. Human values have proven to be an important factor in the behaviour of individuals and leaders. The aim of this study is twofold. The first is to validate Schwartz’s survey of human values.
...
Gavalda, A, Duch, J, GomezGardeñes, J.
Phys. Rev. E
85
,
026112
(2012).
In this paper we study the jamming transition in complex adaptive networks. We introduce an adaptation mechanism that modifies the weight of the communication channels in order to delay the congestion onset. Adaptivity takes place locally as it is driven by each node of the network. Surprisingly, regardless of the
...
Guimera, R, SalesPardo, M.
PLOS ONE
6 (11)
,
e27188
(2011).
Successful attempts to predict judges' votes shed light into how legal decisions are made and, ultimately, into the behavior and evolution of the judiciary. Here, we investigate to what extent it is possible to make predictions of a justice's vote based on the other justices' votes in the same case.
...
Bianco, CL, Massucci, FA, Ruffini, R.
Int. J. Mod. Phys. D
20
,
1919
1929
(2011).
Due to the ultrarelativistic velocity of the expanding "fireshell" (Lorentz gamma factor gamma similar to 10(2) 10(3)), photons emitted at the same time from the fireshell surface do not reach the observer at the same arrival time. In interpreting GammaRay Bursts (GRBs) it is crucial to determine the properties of
...
Quapp, W, Bofill, JM, AguilarMogas, A.
Theor. Chem. Acc.
129
,
803
821
(2011).
Valleyridge inflection points (VRI) on the potential energy surface for the ring opening of the cyclopropyl radical to allyl radical are determined using the tool of Newton trajectories (Quapp and Schmidt in Theor Chem Acc 128: 47, 2011). VRIs play a role in the understanding of bifurcating reactions. The region
...
Gao, JT, Guimera, R, Lia, H, Mendes Pinto, I, SalesPardo, M, Wai, SC, Rubinstein, B, Li, R.
Proc. Natl. Acad. Sci. U. S. A.
108
,
7647
7652
(2011).
In this study, we investigated on a systems level how complex protein interactions underlying cell polarity in yeast determine the dynamic association of proteins with the polar cortical domain (PCD) where they localize and perform morphogenetic functions. We constructed a network of physical interactions among >100 proteins localized to the
...
Gonzalez, J, Caballero, M, AguilarMogas, A, TorrentSucarrat, M, Crehuet, R, Sole, A, Gimenez, X, Olivella, S, Bofill, JM, Anglada, JM.
Theor. Chem. Acc.
128
,
579
592
(2011).
The reaction between the HO radical and (H2O)n (n = 1, 3) clusters has been investigated employing highlevel quantum mechanical calculations using DFTBH&HLYP, QCISD, and CCSD(T) theoretical approaches in connection with the 6311 + G(2df,2p), augccpVTZ, and augccpVQZ basis sets. The rate constants have also been calculated and the tunneling
...
Guimera, R, Stouffer, DB, SalesPardo, M, Leicht, EA, Newman, MEJ, Amaral, LAN.
Ecology
91
,
2941
2951
(2010).
The response of an ecosystem to perturbations is mediated by both antagonistic and facilitative interactions between species. It is thought that a community's resilience depends crucially on the food webthe network of trophic interactionsand on the food web's degree of compartmentalization. Despite its ecological importance, compartmentalization and the mechanisms that
...
Maroulis, S, Guimera, R, Petry, H, Stringer, MJ, Gomez, LM, Amaral, LAN, Wilensky, U.
Science
330
,
38
39
(2010).
Agentbased modeling and network analysis can help integrate knowledge on "microlevel" mechanisms and "macrolevel" effects.
...
AguilarMogas, A, Gimenez, X, Bofill, JM.
J. Comput. Chem.
31
,
2510
2525
(2010).
The intrinsic reaction coordinate (IRC) curve is used widely as a representation of the Reaction Path and can be parameterized taking the potential energy as a reaction coordinate (AguilarMogas et al., J Chem Phys 2008, 128, 104102). Taking this parameterization and its variational nature, an algorithm is proposed that permits
...
Stringer, MJ, SalesPardo, M, Amaral, LAN.
J. Am. Soc. Inf. Sci. Technol.
61
,
1377
1385
(2010).
A central issue in evaluative bibliometrics is the characterization of the citation distribution of papers in the scientific literature. Here, we perform a largescale empirical analysis of journals from every field in Thomson Reuters' Web of Science database. We find that only 30 of the 2,184 journals have citation distributions
...
Choffnes, DR, Duch, J, Malmgren, RD, Guimera, R, Bustamante, FE, Amaral, LAN.
Proc. of the 9th International Workshop on PeertoPeer Systems (IPTPS)
,
(2010).
While P2P systems benefit from large numbers of interconnected nodes, each of these connections provides an opportunity for eavesdropping. Using only the connection patterns gathered from 10,000 BitTorrent (BT) users during a onemonth period, we determine whether randomized connection patterns give rise to communities of users. Even though connections in
...
Arenas, A, Cabrales, A, Danon, L, DiazGuilera, A, Guimera, R, VegaRedondo, F.
Rev. Econ. Des.
14
,
75
93
(2010).
We propose a stylized model of a problemsolving organization whose internal communication structure is given by a fixed network. Problems arrive randomly anywhere in this network and must find their way to their respective specialized solvers by relying on local information alone. The organization handles multiple problems simultaneously. For this
...
Arias, S. Galera, E. Muñoz, A. García, F. Magarolas, D. Ollé, N. Sáez, J.A. Mera, N. RoviraAsenjo .
International Journal of Arts and Sciences
3
,
189
198
(2010).
The educational method known as “ProjectBased Learning”, which is applied in the Escola Tècnica Superior d’Enginyeria Química (ETSEQ) of the Universitat Rovira i Virgili (URV), provides an appropriate environment for testing current trends concerning leadership in teams. Recent studies have shown that men exercise an autocratic and transactional leadership style
...
Guimera, R, SalesPardo, M.
Proc. Natl. Acad. Sci. U. S. A.
106
,
22073
22078
(2009).
Network analysis is currently used in a myriad of contexts, from identifying potential drug targets to predicting the spread of epidemics and designing vaccination strategies and from finding friends to uncovering criminal activity. Despite the promise of the network approach, the reliability of network data is a source of great
...
Sawardecker, EN, Amundsen, CA, SalesPardo, M, Amaral, LAN.
Eur. Phys. J. B
72
,
671
677
(2009).
Most realworld networks considered in the literature have a modular structure. Analysis of these realworld networks often are performed under the assumption that there is only one type of node. However, social and biochemical systems are often bipartite networks, meaning that there are two exclusive sets of nodes, and that
...
Agusti Solanas, Arnau Gavalda and Robert Rallo.
International Conference on Artificial Neural Networks
LNCS 5768
,
525
535
(2009).
The protection of personal privacy is paramount, and consequently many e?orts have been devoted to the study of data protection techniques. Governments, statistical agencies and corporations must protect the privacy of the individuals while guaranteeing the right of the society to knowledge. Microaggregation is one of the most promising solutions
...
Gonzalez, MF, AguilarMogas, A, Gonzalez, J, Crehuet, R, Anglada, JM, Bofill, JM, Gimenez, X.
Theor. Chem. Acc.
123
,
51
58
(2009).
Formation, persistence and decay of temporarily trapped states, the timedependent generalization of resonances, are analysed within the framework of Bohmian Mechanics. More specifically, the socalled Bohm's total potential, the sum of classical plus Bohm's quantum potential, is used. It is found that both formation and decay are triggered by the
...
Sawardecker, EN, SalesPardo, M, Amaral, LAN.
Eur. Phys. J. B
67
,
277
284
(2009).
Most networks found in social and biochemical systems have modular structures. An important question prompted by the modularity of these networks is whether nodes can be said to belong to a single group. If they cannot, we would need to consider the role of "overlapping communities." Despite some efforts in
...
Seaver, SMD, Moreira, AA, SalesPardo, M, Malmgren, RD, Diermeier, D, Amaral, LAN.
Eur. Phys. J. B
67
,
369
375
(2009).
We use agentbased modeling to investigate the effect of conservatism and partisanship on the efficiency with which large populations solve the density classification task  a paradigmatic problem for information aggregation and consensus building. We find that conservative agents enhance the populations' ability to efficiently solve the density classification task
...
De Martino, A, Martelli, C, Massucci, FA.
EPL
85
,
art. no. 38007
(2009).
We study a simplified, solvable model of a fully connected metabolic network with constrained quenched disorder to mimic the conservation laws imposed by stoichiometry on chemical reactions. Within a spinglass type of approach, we show that in the presence of a conserved metabolic pool the flux state corresponding to maximal
...
AguilarMogas, A, Gimenez, X, Bofill, JM.
J. Chem. Phys.
128
,
art. no. 104102
(2008).
The intrinsic reaction coordinate curve (IRC), normally proposed as a representation of a reaction path, is parametrized as a function of the potential energy rather than the arclength. This change in the parametrization of the curve implies that the values of the energy of the potential energy surface points, where
...
Stringer, MJ, SalesPardo, M, Amaral, LAN.
PLoS One
3
,
art. no. e1683
(2008).
Background: The rise of electronic publishing [1], preprint archives, blogs, and wikis is raising concerns among publishers, editors, and scientists about the present day relevance of academic journals and traditional peer review [2]. These concerns are especially fuelled by the ability of search engines to automatically identify and sort information
...
Kho, A, SalesPardo, M, Wilson, J.
IEEE Eng. Med. Biol. Mag.
27
,
26
28
(2008).
...
SalesPardo, M, Chan, AOB, Amaral, LAN, Guimera, R.
Gene
402
,
81
93
(2007).
Understanding evolutionary relationships between species can shed new light into the rooting of the tree of life and the origin of eukaryotes, thus, resulting in a long standing interest in accurately assessing evolutionary parameters at time scales on the order of a billion of years. Prior work suggests large variability
...
SalesPardo, M, Guimera, R, Moreira, AA, Amaral, LAN.
Proc. Natl. Acad. Sci. U. S. A.
104
,
15224
15229
(2007).
Extracting understanding from the growing "sea" of biological and socioeconomic data is one of the most pressing scientific challenges facing us. Here, we introduce and validate an unsupervised method for extracting the hierarchical organization of complex biological, social, and technological networks. We define an ensemble of hierarchically nested random graphs,
...
Guimera, R, SalesPardo, M, Amaral, LAN.
Phys. Rev. E
76
,
art. no. 036102
(2007).
Modularity is one of the most prominent properties of realworld complex networks. Here, we address the issue of module identification in two important classes of networks: bipartite networks and directed unipartite networks. Nodes in bipartite networks are divided into two nonoverlapping sets, and the links must have one end node
...
Guimera, R, SalesPardo, M, Amaral, LAN.
Bioinformatics
23
,
1616
1622
(2007).
Motivation: The lack of new antimicrobials, combined with increasing microbial resistance to old ones, poses a serious threat to public health. With hundreds of genomes sequenced, systems biology promises to help in solving this problem by uncovering new drug targets. Results: Here, we propose an approach that is based on
...
Guimera, R, SalesPardo, M, Amaral, LAN.
Nat. Phys.
3
,
63
69
(2007).
In physical, biological, technological and social systems, interactions between units give rise to intricate networks. Thesetypically nontrivialstructures, in turn, critically affect the dynamics and properties of the system. The focus of most current research on complex networks is, still, on global network properties. A caveat of this approach is that
...
AguilarMogas, A, Crehuet, R, Gimenez, X, Bofill, JM.
Mol. Phys.
105
,
2475
2492
(2007).
A mathematical analysis of several algorithms, for the integration of the differential equation associated to the Intrinsic Reaction Coordinate path, is performed. This analysis first shows that the Intrinsic Reaction Coordinate path can be derived from a variational problem, so that it has the properties of an extremal curve. Then,
...
AguilarMogas, A, Gimenez, X, Bofill, J.
Chem. Phys. Lett.
432
,
375
382
(2006).
A new algorithm for the integration of the intrinsic reaction coordinate path on a potential energy surface is proposed, based in solving the set of differential equations associated to the corresponding characteristic curve, rather than the differential equation of the curve itself. The integration of this set of differential equations
...
Guimera, R, Danon, L, DiazGuilera, A, Giralt, E, Arenas, A.
J. Econ. Behav. Organ.
61
,
653
667
(2006).
The formal chart of an organization is intended to prescribe how employees interact. However, ties between individuals arise for personal, political, and cultural reasons. The characterization of the structure of such informal networks behind the formal chart is a key element for successful management. We surmise that the exchange of
...
Amaral, LAN, Guimera, R.
Nat. Phys.
2
,
75
76
(2006).
...
Guimera, R, SalesPardo, M.
Mol. Syst. Biol.
2
,
art. no. 42
(2006).
...
Guimera, R, Mossa, S, Turtschi, A, Amaral, LAN.
Proc. Natl. Acad. Sci. U. S. A.
102
,
7794
7799
(2005).
We analyze the global structure of the worldwide air transportation network, a critical infrastructure with an enormous impact on local, national, and international economies. We find that the worldwide air transportation network is a scalefree smallworld network. In contrast to the prediction of scalefree network models, however, we find that
...
SalesPardo, M, Guimera, R, Moreira, AA, Widom, J, Amaral, LAN.
Phys. Rev. E
71
,
art. no. 051902
(2005).
To gain a deeper insight into cellular processes such as transcription and translation, one needs to uncover the mechanisms controlling the configurational changes of nucleic acids. As a step toward this aim, we present here a mesoscopiclevel computational model that provides a new window into nucleic acid dynamics. We model
...
Stouffer, DB, Camacho, J, Guimera, R, Ng, CA, Amaral, LAN.
Ecology
86
,
1301
1311
(2005).
Understanding the structure of food webs, and the mechanisms that give rise to this structure, is one of the most challenging problems in ecology. We analyze from a statistical physics perspective the network structure of model food webs and of 15 community food webs from a variety of environments, including
...
Guimera, R, Uzzi, B, Spiro, J, Amaral, LAN.
Science
308
,
697
702
(2005).
Agents in creative enterprises are embedded in networks that inspire, support, and evaluate their work. Here, we investigate how the mechanisms by which creative teams selfassemble determine the structure of these collaboration networks. We propose a model for the selfassembly of creative teams that has its basis in three parameters:
...
Guimera, R, Amaral, LAN.
Nature
433
,
895
900
(2005).
Highthroughput techniques are leading to an explosive growth in the size of biological databases and creating the opportunity to revolutionize our understanding of life and disease. Interpretation of these data remains, however, a major scientific challenge. Here, we propose a methodology that enables us to extract and display information contained
...
Guimera, R, Amaral, LAN.
J. Stat. Mech.Theory Exp.
,
art. no. P02001
(2005).
Integrative approaches to the study of complex systems demand that one knows the manner in which the parts comprising the system are connected. The structure of the complex network defining the interactions provides insight into the function and evolution of the components of the system. Unfortunately, the large size and
...
Guimera, R, SalesPardo, M, Amaral, LAN.
Phys. Rev. E
70
,
art. no. 025101
(2004).
The mechanisms by which modularity emerges in complex networks are not well understood but recent reports have suggested that modularity may arise from evolutionary selection. We show that finding the modularity of a network is analogous to finding the groundstate energy of a spin system. Moreover, we demonstrate that, due
...
Arenas, A, Danon, L, DiazGuilera, A, Gleiser, PM, Guimera, R.
Eur. Phys. J. B
38
,
373
380
(2004).
We present an empirical study of different social networks obtained from digital repositories. Our analysis reveals the community structure and provides a useful visualising technique. We investigate the scaling properties of the community size distribution, and find that all the networks exhibit power law scaling in the community size distributions
...
Guimera, R, Amaral, LAN.
Eur. Phys. J. B
38
,
381
385
(2004).
Recently, we have presented the first exhaustive analysis of the worldwide airport network. Two important results of that study are that: (i) the worldwide airport network is a smallworld network with powerlaw decaying degree and betweenness centrality distributions; (ii) the most connected cities (largest degree) are typically not the most
...
Arenas, A, Danon, L, DiazGuilera, A, Guimera, R.
LECT NOTE COMPUT SCI
3038
,
1078
1085
(2004).
We present a formalism that is able to cope with search and congestion simultaneously. This formalism avoids the problem of simulating the dynamics of the searchcommunication process which turns out to be impracticable, specially close to the congestion point where search costs (time) diverge.
...
Palassini, M, Sales, M, Ritort, F.
Phys. Rev. B
68
,
art. no. 224430
(2003).
We present a numerical study of the orderparameter fluctuations for Ising spin glasses in three and four dimensions at very low temperatures and without an external field. Accurate measurements of two previously introduced parameters A and G show that the order parameter is not selfaveraging, consistent with a zerotemperature thermal
...
Bofill, P, Guimera, R, Torras, C.
Neural Netw.
16
,
1421
1428
(2003).
This paper describes an experimental comparison between a discrete stochastic optimization procedure (Simulated Annealing, SA) and a continuous deterministic one (Mean Field Annealing), as applied to the generation of Balanced Incomplete Block Designs (BIBDs). A neural cost function for BIBD generation is proposed with connections of arity four, and its
...
Guimera, R, Danon, L, DiazGuilera, A, Giralt, F, Arenas, A.
Phys. Rev. E
68
,
art. no. 065103
(2003).
We propose a procedure for analyzing and characterizing complex networks. We apply this to the social network as constructed from email communications within a medium sized university with about 1700 employees. Email networks provide an accurate and nonintrusive description of the flow of information within human organizations. Our results reveal
...
Picco, M, Ritort, F, Sales, M.
Phys. Rev. B
67
,
art. no. 184421
(2003).
An approach to determine the value of the zerotemperature thermal exponent theta in spin glasses is presented. It consists in describing the energy level spectrum in spin glasses only in terms of the properties of the lowest energy droplets and the lowest droplet exponents (LDE's) lambda(l),theta(l) that describe the statistics
...
Sales, M, Bouchaud, JP, Ritort, F.
J. Phys. AMath. Gen.
36
,
665
684
(2003).
We study analytically and numerically the role of temperature shifts in the simplest model where the energy landscape is explicitly hierarchical, namely the Sinai model. This model has both attractive features (there are valleys within valleys in a strict selfsimilar sense), but also one important drawback: there is no phase
...
Arenas, A, Cabrales, A, DiazGuilera, A, Guimera, R, VegaRedondo, F.
LECT NOTES PHYS
625
,
175
194
(2003).
A model of communication that is able to cope simultaneously with the problems of search and congestion is presented. We investigate the communication dynamics in model networks. Those networks consist in a regular lattice ordering plus some longrange shortcuts with a given probability. The destination nodes of the shortcuts are
...
Guimera, R, DiazGuilera, A, VegaRedondo, F, Cabrales, A, Arenas, A.
Phys. Rev. Lett.
89
,
art. no. 248701
(2002).
The problem of searchability in decentralized complex networks is of great importance in computer science, economy, and sociology. We present a formalism that is able to cope simultaneously with the problem of search and the congestion effects that arise when parallel searches are performed, and we obtain expressions for the
...
Guimera, R, Arenas, A, DiazGuilera, A, Giralt, F.
Phys. Rev. E
66
,
art. no. 026704
(2002).
We study the dynamical properties of a collection of models for communication processes, characterized by a single parameter xi representing the relation between information load of the nodes and its ability to deliver this information. The critical transition to congestion reported so far occurs only for xi=1. This case is
...
Camacho, J, Guimera, R, Amaral, LAN.
Phys. Rev. Lett.
88
,
art. no. 228102
(2002).
We analyze the properties of seven community food webs from a variety of environments, including freshwater, marinefreshwater interfaces, and terrestrial environments. We uncover quantitative unifying patterns that describe the properties of the diverse trophic webs considered and suggest that statistical physics concepts such as scaling and universality may be useful
...
Sales, M, Yoshino, H.
Phys. Rev. E
65
,
art. no. 066131
(2002).
We examine the sensitiveness of the freeenergy landscape of a directed polymer in random media with respect to various kinds of infinitesimally weak perturbation including the intriguing case of temperature chaos. To this end, we combine the replica Bethe Ansatz approach outlined by Sales and Yoshino (eprint condmat/0112384), the mapping
...
Camacho, J, Guimera, R, Amaral, LAN.
Phys. Rev. E
65
,
art. no. 030901
(2002).
We investigate numerically and analytically a recently proposed model for food webs [Nature 404, 180 (2000)] in the limit of large web sizes and sparse interaction matrices. We obtain analytical expressions for several quantities with ecological interest, in particular, the probability distributions for the number of prey and the number
...
Guimera, R, Arenas, A, DiazGuilera, A.
Physica A
299
,
247
252
(2001).
We study a general and simple model for communication processes. In the model, agents in a network (in particular, an organization) interchange information packets following simple rules that take into account the limited capability of the agents to deal with packets and the cost associated with the existence of open
...
Sales, M, Bouchaud, JP.
Europhys. Lett.
56
,
181
186
(2001).
We show that the Random Energy Model has interesting rejuvenation properties in its frozen phase. Different susceptibilities to temperature changes, for the free energy and for other ( magnetic) observables, can be computed exactly. These susceptibilities diverge at the transition temperature, as (1T/Tc)(3) for the free energy.
...
Ritort, F, Sales, M.
J. Phys. AMath. Gen.
34
,
L333
L339
(2001).
We present a constructive approach to obtain information about the compactness and shape of largescale lowest excitations in disordered systems by studying order parameter fluctuations (OPF) at low temperatures. We show that the parameter G that measures OFF is 1/3 at T = 0 provided the ground state is unique
...
Arenas, A, DiazGuilera, A, Guimera, R.
Phys. Rev. Lett.
86
,
3196
3199
(2001).
We present a simple model of communication in networks with hierarchical branching. We analyze the behavior of the model from the viewpoint of critical systems under different situations. For certain values of the parameters, a continuous phase transition between a sparse and a congested regime is observed and accurately described
...
Picco, M, Ritort, F, Sales, M.
Eur. Phys. J. B
19
,
565
582
(2001).
The rise of parameters measuring orderparameter fluctuations: (OPF) has been encouraged by the recent results reported in reference [2,3] which show that two of these parameters, G and G,, take universal values in the lim(T >0). In this paper we present a detailed study of parameters measuring OPF for two
...
Ritort, F, Sales, M.
J. Phys. AMath. Gen.
33
,
6505
6526
(2000).
We study orderparameter fluctuations (OPF) in disordered systems by considering the behaviour of some recently introduced parameters G, G(c) which have proven very useful in locating phase transitions. We prove that both parameters G (for disconnected overlap disorder averages) and G(c) (for connected disorder averages) take the respective universal values
...
Sales, M, Hernandez, JM, Tejada, J, Martinez, JL.
Phys. Rev. B
60
,
14557
14560
(1999).
In this paper we discuss both theoretical and experimental results on the time dependence of the heat capacity of oriented Mn(12) magnetic clusters when a magnetic field is applied along their easy axis. Our calculations are based on the existence of two contributions. The first one is associated with the
...
del Barco, E, Hernandez, JM, Sales, M, Tejada, J, Rakoto, H, Broto, JM, Chudnovsky, EM.
Phys. Rev. B
60
,
11898
11901
(1999).
We report experimental studies and suggest a quantitative model of spin relaxation in Mn12 acetate in a pulsed magnetic field in the temperature range 1.95.0 K. When the field applied along the anisotropy axis is swept at 140 T/s through a nonmagnetized Mn12 acetate sample, the sample's magnetization switches, within
...
Bohigas, X, del Barco, E, Sales, M, Tejada, J.
J. Magn. Magn. Mater.
196
,
455
457
(1999).
In this paper, we comment on experiments we have carried out on ceramic perovskites of composition La0.65Ca0.35Ti1xMnxO3. From low and highfield magnetic measurements recorded at different temperatures, we have discovered the existence of a large entropic change associated to the ferrimagneticparamagnetic transition. Our conclusion is that these materials are excellent
...
Bohigas, X, Tejada, J, del Barco, E, Zhang, XX, Sales, M.
Appl. Phys. Lett.
73
,
390
392
(1998).
A large entropy variation (magnetocaloric effect) has been discovered in ceramic perovskites with the formulas La0.65Ca0.35Ti1xMnxO3z and La0.5+x+yLi0.53yTi13xMn3xO3z. Both Curie temperature and entropy change were studied from 4.2 to 400 K for different stoichiometric compositions and applied magnetic fields. Our conclusion is that these materials are excellent candidates for working
...