Showing papers by "University of Houston published in 2013"

The cancer genome atlas pan-cancer analysis project

Abstract: The Cancer Genome Atlas (TCGA) Research Network has profiled and analyzed large numbers of human tumors to discover molecular aberrations at the DNA, RNA, protein and epigenetic levels. The resulting rich data provide a major opportunity to develop an integrated picture of commonalities, differences and emergent themes across tumor lineages. The Pan-Cancer initiative compares the first 12 tumor types profiled by TCGA. Analysis of the molecular aberrations and their functional roles across tumor types will teach us how to extend therapies effective in one cancer type to others with a similar genomic profile.

Comprehensivemolecular characterization of clear cell renal cell carcinoma

Abstract: Genetic changes underlying clear cell renal cell carcinoma (ccRCC) include alterations in genes controlling cellular oxygen sensing (for example, VHL) and the maintenance of chromatin states (for example, PBRM1). We surveyed more than 400 tumours using different genomic platforms and identified 19 significantly mutated genes. The PI(3)K/AKT pathway was recurrently mutated, suggesting this pathway as a potential therapeutic target. Widespread DNA hypomethylation was associated with mutation of the H3K36 methyltransferase SETD2, and integrative analysis suggested that mutations involving the SWI/SNF chromatin remodelling complex (PBRM1, ARID1A, SMARCA4) could have far-reaching effects on other pathways. Aggressive cancers demonstrated evidence of a metabolic shift, involving downregulation of genes involved in the TCA cycle, decreased AMPK and PTEN protein levels, upregulation of the pentose phosphate pathway and the glutamine transporter genes, increased acetyl-CoA carboxylase protein, and altered promoter methylation of miR-21 (also known as MIR21) and GRB10. Remodelling cellular metabolism thus constitutes a recurrent pattern in ccRCC that correlates with tumour stage and severity and offers new views on the opportunities for disease treatment.

Contact Angle and Wetting Properties

Abstract: This chapter highlights a variety of techniques that are commonly used to measure contact angles, including the conventional telescope-goniometer method, the Wilhelmy balance method, and the more recently developed drop-shape analysis methods. The various applications and limitations of these techniques are described. Notably, studies of ultrasmall droplets on solid surfaces allow wetting theories to be tested down to the nanometer scale, bringing new insight to contact angle phenomena and wetting behavior.

Synthetic nanoparticles functionalized with biomimetic leukocyte membranes possess cell-like functions

Abstract: The therapeutic efficacy of systemic drug-delivery vehicles depends on their ability to evade the immune system, cross the biological barriers of the body and localize at target tissues. White blood cells of the immune system--known as leukocytes--possess all of these properties and exert their targeting ability through cellular membrane interactions. Here, we show that nanoporous silicon particles can successfully perform all these actions when they are coated with cellular membranes purified from leukocytes. These hybrid particles, called leukolike vectors, can avoid being cleared by the immune system. Furthermore, they can communicate with endothelial cells through receptor-ligand interactions, and transport and release a payload across an inflamed reconstructed endothelium. Moreover, leukolike vectors retained their functions when injected in vivo, showing enhanced circulation time and improved accumulation in a tumour.

Tuning the Magnetic Properties of Nanoparticles

Abstract: The tremendous interest in magnetic nanoparticles (MNPs) is reflected in published research that ranges from novel methods of synthesis of unique nanoparticle shapes and composite structures to a large number of MNP characterization techniques, and finally to their use in many biomedical and nanotechnology-based applications. The knowledge gained from this vast body of research can be made more useful if we organize the associated results to correlate key magnetic properties with the parameters that influence them. Tuning these properties of MNPs will allow us to tailor nanoparticles for specific applications, thus increasing their effectiveness. The complex magnetic behavior exhibited by MNPs is governed by many factors; these factors can either improve or adversely affect the desired magnetic properties. In this report, we have outlined a matrix of parameters that can be varied to tune the magnetic properties of nanoparticles. For practical utility, this review focuses on the effect of size, shape, composition, and shell-core structure on saturation magnetization, coercivity, blocking temperature, and relaxation time.

Time to Change What to Sow: Risk Preferences and Technology Adoption Decisions of Cotton Farmers in China

Abstract: This paper examines the role of individual risk attitudes in the decision to adopt a new form of agricultural biotechnology in China. I conducted a survey and a field experiment to elicit the risk preferences of Chinese farmers, who faced the decision of whether to adopt genetically modified Bt cotton a decade ago. In my analysis, I expand the measurement of risk preferences beyond expected utility theory to incorporate prospect theory. I find that farmers who are more risk averse or more loss averse adopt Bt cotton later. Farmers who overweight small probabilities adopt Bt cotton earlier.

Centrality dependence of pi, K, and p production in Pb-Pb collisions at root s(NN)=2.76 TeV

Abstract: In this paper measurements are presented of pi(+/-), K-+/-, p, and (p) over bar production at midrapidity (vertical bar y vertical bar < 0.5), in Pb-Pb collisions at root s(NN) = 2.76 TeV as a function of centrality. The measurement covers the transverse-momentum (p(T)) range from 100, 200, and 300 MeV/c up to 3, 3, and 4.6 GeV/c for pi, K, and p, respectively. The measured p(T) distributions and yields are compared to expectations based on hydrodynamic, thermal and recombination models. The spectral shapes of central collisions show a stronger radial flow than measured at lower energies, which can be described in hydrodynamic models. In peripheral collisions, the p(T) distributions are not well reproduced by hydrodynamic models. Ratios of integrated particle yields are found to be nearly independent of centrality. The yield of protons normalized to pions is a factor similar to 1.5 lower than the expectation from thermal models.

On the immortality of television sets: "function" in the human genome according to the evolution-free gospel of ENCODE.

Abstract: A recent slew of ENCyclopedia Of DNA Elements (ENCODE) Consortium publications, specifically the article signed by all Consortium members, put forward the idea that more than 80% of the human genome is functional. This claim flies in the face of current estimates according to which the fraction of the genome that is evolutionarily conserved through purifying selection is less than 10%. Thus, according to the ENCODE Consortium, a biological function can be maintained indefinitely without selection, which implies that at least 80 − 10 = 70% of the genome is perfectly invulnerable to deleterious mutations, either because no mutation can ever occur in these “functional” regions or because no mutation in these regions can ever be deleterious. This absurd conclusion was reached through various means, chiefly by employing the seldom used “causal role” definition of biological function and then applying it inconsistently to different biochemical properties, by committing a logical fallacy known as “affirming the consequent,” by failing to appreciate the crucial difference between “junk DNA” and “garbage DNA,” by using analytical methods that yield biased errors and inflate estimates of functionality, by favoring statistical sensitivity over specificity, and by emphasizing statistical significance rather than the magnitude of the effect. Here, we detail the many logical and methodological transgressions involved in assigning functionality to almost every nucleotide in the human genome. The ENCODE results were predicted by one of its authors to necessitate the rewriting of textbooks. We agree, many textbooks dealing with marketing, mass-media hype, and public relations may well have to be rewritten.

Does Mandatory Adoption of IFRS Improve Accounting Quality? Preliminary Evidence

Abstract: We provide evidence on the preliminary effects of mandatory adoption of International Financial Reporting Standards (IFRS) on accounting quality for a relatively broad set of firms from 20 countries that adopted IFRS in 2005 relative to a benchmark group of firms from countries that did not adopt IFRS matched on the strength of legal enforcement, industry, size, book-to-market, and accounting performance. Relative to these benchmark firms, we find that IFRS firms exhibit significant increases in income smoothing and aggressive reporting of accruals, and a significant decrease in timeliness of loss recognition; however we do not find significant differences across IFRS and benchmark firms in meeting or beating earnings targets. Our findings contrast with findings in earlier studies which suggest that IFRS adoption leads to increased accounting quality. Our findings primarily hold for firms in strong enforcement countries, which suggests that enforcement mechanisms in these countries were not able to counter the initial effects of greater flexibility in IFRS relative to domestic GAAP.

High-throughput sequencing of the paired human immunoglobulin heavy and light chain repertoire.

Abstract: Each B-cell receptor consists of a pair of heavy and light chains. High-throughput sequencing can identify large numbers of heavy- and light-chain variable regions (V(H) and V(L)) in a given B-cell repertoire, but information about endogenous pairing of heavy and light chains is lost after bulk lysis of B-cell populations. Here we describe a way to retain this pairing information. In our approach, single B cells (>5 × 10(4) capacity per experiment) are deposited in a high-density microwell plate (125 pl/well) and lysed in situ. mRNA is then captured on magnetic beads, reverse transcribed and amplified by emulsion V(H):V(L) linkage PCR. The linked transcripts are analyzed by Illumina high-throughput sequencing. We validated the fidelity of V(H):V(L) pairs identified by this approach and used the method to sequence the repertoire of three human cell subsets-peripheral blood IgG(+) B cells, peripheral plasmablasts isolated after tetanus toxoid immunization and memory B cells isolated after seasonal influenza vaccination.

Efficiency Resource Allocation for Device-to-Device Underlay Communication Systems: A Reverse Iterative Combinatorial Auction Based Approach

Abstract: Peer-to-peer communication has been recently considered as a popular issue for local area services. An innovative resource allocation scheme is proposed to improve the performance of mobile peer-to-peer, i.e., device-to-device (D2D), communications as an underlay in the downlink (DL) cellular networks. To optimize the system sum rate over the resource sharing of both D2D and cellular modes, we introduce a reverse iterative combinatorial auction as the allocation mechanism. In the auction, all the spectrum resources are considered as a set of resource units, which as bidders compete to obtain business while the packages of the D2D pairs are auctioned off as goods in each auction round. We first formulate the valuation of each resource unit, as a basis of the proposed auction. And then a detailed non-monotonic descending price auction algorithm is explained depending on the utility function that accounts for the channel gain from D2D and the costs for the system. Further, we prove that the proposed auction-based scheme is cheat-proof, and converges in a finite number of iteration rounds. We explain non-monotonicity in the price update process and show lower complexity compared to a traditional combinatorial allocation. The simulation results demonstrate that the algorithm efficiently leads to a good performance on the system sum rate.

Servant leaders inspire servant followers: Antecedents and outcomes for employees and the organization

Abstract: Despite widespread adoption of servant leadership, we are only beginning to understand its true utility across multiple organizational levels. Our purpose was to test the relationship between personality, servant leadership, and critical follower and organizational outcomes. Using a social influence framework, we proposed that leader agreeableness and extraversion affect follower perceptions of servant leadership. In turn, servant leaders ignite a cycle of service by role-modeling servant behavior that is then mirrored through coworker helping behavior and high-quality customer service, as well as reciprocated through decreased withdrawal. Using a multilevel, multi-source model, we surveyed 224 stores of a U.S. retail organization, including 425 followers, 110 store managers, and 40 regional managers. Leader agreeableness was positively and extraversion was negatively related to servant leadership, which was associated with decreased follower turnover intentions and disengagement. At the group-level, service climate mediated the effects of servant leadership on follower turnover intentions, helping and sales behavior.

Planning cancer control in Latin America and the Caribbean

Abstract: Non-communicable diseases, including cancer, are overtaking infectious disease as the leading health-care threat in middle-income and low-income countries. Latin American and Caribbean countries are struggling to respond to increasing morbidity and death from advanced disease. Health ministries and health-care systems in these countries face many challenges caring for patients with advanced cancer: inadequate funding; inequitable distribution of resources and services; inadequate numbers, training, and distribution of health-care personnel and equipment; lack of adequate care for many populations based on socioeconomic, geographic, ethnic, and other factors; and current systems geared toward the needs of wealthy, urban minorities at a cost to the entire population. This burgeoning cancer problem threatens to cause widespread suffering and economic peril to the countries of Latin America. Prompt and deliberate actions must be taken to avoid this scenario. Increasing efforts towards prevention of cancer and avoidance of advanced, stage IV disease will reduce suffering and mortality and will make overall cancer care more affordable. We hope the findings of our Commission and our recommendations will inspire Latin American stakeholders to redouble their efforts to address this increasing cancer burden and to prevent it from worsening and threatening their societies.

Genomic analyses identify distinct patterns of selection in domesticated pigs and Tibetan wild boars

Abstract: We report the sequencing at 131× coverage, de novo assembly and analyses of the genome of a female Tibetan wild boar. We also resequenced the whole genomes of 30 Tibetan wild boars from six major distributed locations and 18 geographically related pigs in China. We characterized genetic diversity, population structure and patterns of evolution. We searched for genomic regions under selection, which includes genes that are involved in hypoxia, olfaction, energy metabolism and drug response. Comparing the genome of Tibetan wild boar with those of neighboring Chinese domestic pigs further showed the impact of thousands of years of artificial selection and different signatures of selection in wild boar and domestic pig. We also report genetic adaptations in Tibetan wild boar that are associated with high altitudes and characterize the genetic basis of increased salivation in domestic pig.

Centrality determination of Pb-Pb collisions at root s(NN)=2.76 TeV with ALICE

Abstract: This publication describes the methods used to measure the centrality of inelastic Pb-Pb collisions at a center-of-mass energy of 2.76 TeV per colliding nucleon pair with ALICE. The centrality is a key parameter in the study of the properties of QCD matter at extreme temperature and energy density, because it is directly related to the initial overlap region of the colliding nuclei. Geometrical properties of the collision, such as the number of participating nucleons and the number of binary nucleon-nucleon collisions, are deduced from a Glauber model with a sharp impact parameter selection and shown to be consistent with those extracted from the data. The centrality determination provides a tool to compare ALICE measurements with those of other experiments and with theoretical calculations.

Postsecondary employment experiences among young adults with an autism spectrum disorder.

Abstract: Objective We examined postsecondary employment experiences of young adults with an autism spectrum disorder (ASD) and compared these outcomes with those of young adults with different disabilities. Method Data were from Wave 5 of the National Longitudinal Transition Study–2 (NLTS2), a nationally representative survey of young adults who had received special education services during high school. We examined the prevalence of ever having had, and currently having, a paid job at 21 to 25 years of age. We analyzed rates of full-time employment, wages earned, number of jobs held since high school, and job types. Results Approximately one-half (53.4%) of young adults with an ASD had ever worked for pay outside the home since leaving high school, the lowest rate among disability groups. Young adults with an ASD earned an average of $8.10 per hour, significantly lower than average wages for young adults in the comparison groups, and held jobs that clustered within fewer occupational types. Odds of ever having had a paid job were higher for those who were older, from higher-income households, and with better conversational abilities or functional skills. Conclusions Findings of worse employment outcomes for young adults with an ASD suggest that this population is experiencing particular difficulty in successfully transitioning into employment. Research is needed to determine strategies for improving outcomes as these young adults transition into adulthood.

In Situ-DRIFTS Study of Selective Catalytic Reduction of NOx by NH3 over Cu-Exchanged SAPO-34

Abstract: The intrinsic mechanism of the selective catalytic reduction (SCR) reaction over a Cu-exchanged SAPO-34 catalyst at low temperature was studied by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), coupled with mass spectrometry to measure inlet and outlet gas concentrations. The evolution of the surface intermediates, as well as the reactivity of NH3 with surface NOx species and NOx with surface NH3 species, was evaluated. In terms of NOx adsorption, surface nitrates and nitrites are the main NOx adsorption species at low temperature. When NO was exposed to the sample with NH3 preadsorbed, surface NH3 was not reactive because of the low surface coverage of nitrates and nitrites. However, the reactivity is significantly enhanced by the inclusion of O2 in the feed, which promotes an increase in the concentration of surface nitrates and nitrites. DRIFTS results also reveal that the low temperature SCR reaction involves the formation of an NH4NO3 intermediate and its subsequent red...

Marketing in Computer-Mediated Environments: Research Synthesis and New Directions

Abstract: Although an extensive body of research has emerged on marketing in computer-mediated environments (CMEs), the literature remains fragmented. As a result, insights and findings have accumulated without an overarching framework that provides structure and guidance to the rapidly-growing literature. We believe this is detrimental to long-term knowledge development in this area. To address this issue, we organize and synthesize findings from the literature using a framework structured around four key interactions in CMEs: consumer-firm interactions, firm-consumer interactions, consumer-consumer interactions, and firm-firm interactions. The proposed framework serves a valuable organizational function and helps identify a broad spectrum of gaps in the literature to advance the next generation of knowledge development.

The Changing Environment of Selling and Sales Management

Abstract: New developments and trends in selling and sales management are creating demands and opportunities that require adaptation and new approaches on the part of both sales organizations and academic researchers. This paper summarizes critical dimensions of change in the environment that affect the practice of selling and sales management and introduces the papers that follow in this Anniversary Special Issue of JPSSM.

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

Abstract: The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.

A tutorial on count regression and zero-altered count models for longitudinal substance use data

Abstract: Critical research questions in the study of addictive behaviors concern how these behaviors change over time: either as the result of intervention or in naturalistic settings. The combination of count outcomes that are often strongly skewed with many zeroes (e.g., days using, number of total drinks, number of drinking consequences) with repeated assessments (e.g., longitudinal follow-up after intervention or daily diary data) present challenges for data analyses. The current article provides a tutorial on methods for analyzing longitudinal substance use data, focusing on Poisson, zero-inflated, and hurdle mixed models, which are types of hierarchical or multilevel models. Two example datasets are used throughout, focusing on drinking-related consequences following an intervention and daily drinking over the past 30 days, respectively. Both datasets as well as R, SAS, Mplus, Stata, and SPSS code showing how to fit the models are available on a supplemental website.

Blaming the organization for abusive supervision: The roles of perceived organizational support and supervisor's organizational embodiment

Abstract: Why do employees who experience abusive supervision retaliate against the organization? We apply organizational support theory to propose that employees hold the organization partly responsible for abusive supervision. Depending on the extent to which employees identify the supervisor with the organization (i.e., supervisor's organizational embodiment), we expected abusive supervision to be associated with low perceived organizational support (POS) and consequently with retribution against the organization. Across 3 samples, we found that abusive supervision was associated with decreased POS as moderated by supervisor's organizational embodiment. In turn, reduced POS was related to heightened counterproductive work behavior directed against the organization and lowered in-role and extra-role performance. These findings suggest that employees partly attribute abusive supervision to negative valuation by the organization and, consequently, behave negatively toward and withhold positive contributions to it.

Textual risk disclosures and investors’ risk perceptions

Abstract: We examine the association between changes in companies’ textual risk disclosures in 10-K filings and changes in stock market and analyst activity around the filings. We find that annual increases in risk disclosures are associated with increased stock return volatility and trading volume around and after the filings. Increases in risk disclosures are also associated with more dispersed forecast revisions around the filings. In contrast to prior literature documenting resolved uncertainties in response to various types of company disclosures, our findings suggest that textual risk disclosures increase investors’ risk perceptions. However, the results are less pronounced for firm-level disclosures that deviate from those of other companies in the same industry and year. These results lend support for critics’ arguments that firm-level risk disclosures are more likely to be boilerplate.

Directed Amination of Non‐Acidic Arene CH Bonds by a Copper–Silver Catalytic System

Abstract: New methods for direct arylation, alkylation, and oxygenation of sp2 carbon-hydrogen bonds in directing-group containing benzenes have resulted in efficient synthetic routes to functionalized arenes.[1] In contrast, direct amination reactions that do not proceed via nitrenoid intermediates[2] are relatively rare. In most cases, palladium catalysis is used for aminations.[3a-p] Furthermore, majority of publications describe intramolecular C-N bond formation.[3a-i] Typically, protected amines or hydroxylamine derivatives are used to install nitrogen moiety. Simple amine coupling partners are employed only rarely. Several deprotonative, copper-catalyzed thiazole and oxazole aminations have been reported.[4b,c,e] Yu has reported a method for palladium-catalyzed benzamide amination by employing a removable auxiliary.[3k] We disclose here a method for an auxiliary-assisted amination of non-acidic benzamide β-C–H bonds and benzylamine derivative γ-C–H bonds that is catalyzed by copper(II) acetate.

Improved measurement of electron antineutrino disappearance at Daya Bay

Abstract: With 2.5× the previously reported exposure, the Daya Bay experiment has improved the measurement of the neutrino mixing parameter sin^2 2θ_(13) = 0.089 ± 0.010(stat) ± 0.005(syst). Reactor anti-neutrinos were produced by six 2.9 GW_(th) commercial power reactors, and measured by six 20-ton target-mass detectors of identical design. A total of 234,217 anti-neutrino candidates were detected in 127 days of exposure. An anti-neutrino rate of 0.944±0.007(stat)±0.003(syst) was measured by three detectors at a flux-weighted average distance of 1648 m from the reactors, relative to two detectors at 470 m and one detector at 576 m. Detector design and depth underground limited the background to 5 ± 0.3% (far detectors) and 2 ± 0.2% (near detectors) of the candidate signals. The improved precision confirms the initial measurement of reactor anti-neutrino disappearance, and continues to be the most precise measurement of θ_(13).

K-S(0) and Lambda Production in Pb-Pb Collisions at root s(NN)=2: 76 TeV

Abstract: The ALICE measurement of K^0_S and {\Lambda} production at mid-rapidity in Pb-Pb collisions at sqrt(sNN) = 2.76 TeV is presented. The transverse momentum (pT) spectra are shown for several collision centrality intervals and in the pT range from 0.4 GeV/c (0.6 GeV/c for {\Lambda}) to 12 GeV/c. The pT dependence of the {\Lambda}/K^0_S ratios exhibits maxima in the vicinity of 3 GeV/c, and the positions of the maxima shift towards higher pT with increasing collision centrality. The magnitude of these maxima increases by almost a factor of three between most peripheral and most central Pb-Pb collisions. This baryon excess at intermediate pT is not observed in pp interactions at sqrt(s) = 0.9 TeV and at sqrt(s) = 7 TeV. Qualitatively, the baryon enhancement in heavy-ion collisions is expected from radial flow. However, the measured pT spectra above 2 GeV/c progressively decouple from hydrodynamical-model calculations. For higher values of pT, models that incorporate the influence of the medium on the fragmentation and hadronization processes describe qualitatively the pT dependence of the {\Lambda}/K^0_S ratio.

Long-range angular correlations of pi, K and p in p-Pb collisions at root s(NN)=5.02 TeV

Abstract: Angular correlations between unidentified charged trigger particles and various species of charged associated particles (unidentified particles, pions, kaons, protons and antiprotons) are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV in the transverse-momentum range 0.3 < p(T) < 4 GeV/c. The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range vertical bar n(lab)vertical bar < 0.8. Fourier coefficients are extracted from the long-range correlations projected onto the azimuthal angle difference and studied as a function of p(T) and in intervals of event multiplicity. In high-multiplicity events, the second-order coefficient for protons, 4, is observed to be smaller than that for pions, v(2)(pi), up to about p(T) = 2 GeV/c. To reduce correlations due to jets, the per-trigger yield measured in low-multiplicity events is subtracted from that in high-multiplicity events. A two-ridge structure is obtained for all particle species. The Fourier decomposition of this structure shows that the second-order coefficients for pions and kaons are similar. The v(2)(p) is found to be smaller at low P-T and larger at higher p(T) than v(2)(pi), with a crossing occurring at about 2 GeV/c. This is qualitatively similar to the elliptic-flow pattern observed in heavy-ion collisions. A mass ordering effect at low transverse momenta is consistent with expectations from hydrodynamic model calculations assuming a collectively expanding system. (C) 2013 CERN. Published by Elsevier B.V. All rights reserved.