bluuebunny/crossref_metadata_2025 huggingface dataset:
Emergent Triglyceride-lowering Therapy With Early High-volume Hemofiltration Against Low–Molecular-Weight Heparin Combined With Insulin in Hypertriglyceridemic Pancreatitis
Authors: He Wen-hua , Yu Min , Zhu Yin , Xia Liang , Liu Pi , Zeng Hao , Zhu Yong , Lv Nong-hua
Published: June 2016

Objectives:

To compare the value of emergent triglyceride (TG)-lowering therapies between early high-volume hemofiltration (HVHF) and low–molecular-weight heparin (LMWH) combined with insulin (LMWH+insulin) as well as their effects on the outcomes of hypertriglyceridemic pancreatitis (HTGP) patients.

Methods:

In this randomized controlled trial, 66 HTGP patients presenting within 3 days after the onset of symptoms from August 2011 to October 2013 were assigned randomly to receive either HVHF or LMWH+insulin as an emergent TG-lowering therapy. Thirty-three patients were included in each group, and the therapy was started as soon as possible after admission. TG levels, clinical outcomes, and inflammatory biomarkers were compared between the 2 groups.

Results:

Thirty-two individuals in the HVHF group and 34 in the LMWH+insulin group were included in the final analysis. Characteristics of the patients in both groups were roughly comparable. HVHF could remove TG from the plasma and achieve its target (<500 mg/dL) in approximately 9 hours, whereas the target was not achieved within 48 hours in patients receiving the LMWH+insulin treatment (P<0.05). However, no differences were found in terms of the majority of the clinical outcomes, including local pancreatic complications (P>0.05), the requirement of surgical intervention (P=0.49), mortality (P=0.49), and the duration of hospitalization (P=0.144). Furthermore, an unexpectedly higher incidence of persistent organ failure was observed in the HVHF group compared with the LMWH+insulin group (risk ratio with HVHF, 2.42; 95% confidence interval, 1.15-5.11; P=0.01). Hospital charges for patients in the HVHF group were approximately 2-fold higher than those for patients in the LMWH+insulin group (5.20±4.90 vs. 2.92±3.21, P=0.03). We selected a systemic inflammatory response syndrome score of at least 2 at baseline as a predictor of SAP patients, and the subgroup analyses showed that HVHF cannot improve the prognosis of the predicted SAP patients compared with the LMWH+insulin group.

Conclusions:

HVHF can lower TG levels more efficiently than LMWH+insulin therapy, but it is not superior in terms of clinical outcomes and costs. Further multicenter studies with large samples are required to clarify the feasibility of administering the HVHF treatment to HTGP patients (ChiCTR-TRC-13003274).
Optimization of a Scoring System to Predict Microscopic Colitis in a Cohort of Patients With Chronic Diarrhea
Authors: Cotter Thomas G. , Binder Moritz , Harper Eugene P. , Smyrk Thomas C. , Pardi Darrell S.
Published: June 2016

Goals:

Our aim was to develop a scoring system to predict risk of microscopic colitis (MC), to identify patients at low risk, potentially avoiding unnecessary biopsies.

Background:

Patients with chronic diarrhea often undergo colonoscopy with biopsy, but few have histologic abnormalities.

Study:

We conducted a retrospective study of patients with chronic diarrhea and a macroscopically normal colonoscopy at our institution over a 9-month period. Multivariable logistic regression assessed the association between predictors and the presence of biopsy-proven MC.

Results:

The derivation cohort included 617 patients. Median age was 55.1 (39.6 to 68.1) years; 397 (64.3%) were female and 81 (13.1%) had MC. Age ≥55 years, duration of diarrhea ≤6 months, ≥5 bowel movements per day, body mass index <30 kg/m2, current smoking, and current use of selective serotonin reuptake inhibitors/serotonin-norepinephrine reuptake inhibitorss and non-steroidal anti-inflammatory drugs were independently associated with MC. A score of ≥10 points in our scoring system, yielded an area under the ROC curve (AUC) of 0.83 with a sensitivity of 93% and specificity of 49% in predicting which patients have MC. The negative predictive value (NPV) was 97.8% (95.0% to 99.1%).

In the validation cohort, the scoring system performed similarly (AUC 0.79, sensitivity 91%, specificity 49%, NPV 97%). By avoiding biopsies in patients at low risk of having MC, costs associated with colon biopsies could be reduced by almost 43%.

Conclusion:

This scoring system including 7 clinical variables was able to identify patients unlikely to have MC, with excellent sensitivity, reasonable specificity, and a high NPV, translating into important potential cost savings.
Profound Vitamin B12 Deficiency in a 1-Year-Old Child in Botswana: A Call to Initiate Early Empiric Therapy
Authors: Gajudhur Juyotee , Slone Jeremy S. , Mehta Parth S. , Mahoney Donald
Published: June 2016

Vitamin B12 deficiency is a rare diagnosis in young children. We present the case of a 1-year-old Zimbabwean child with profound anemia. Further testing revealed undetectable levels of vitamin B12 and positive intrinsic factor antibodies that were drawn after the initiation of empiric treatment with parenteral vitamin B12. We report the evaluation and management of vitamin B12 deficiency in a resource-limited setting. Vitamin B12 deficiency should be considered in children presenting with unexplained cytopenias with consideration of empiric treatment with parenteral vitamin B12, as developmental and neurological complications of vitamin B12 deficiency can be devastating and permanent.
Functional movement disorders
Authors: Teodoro Tiago , Edwards Mark J.
Published: June 2016

Purpose of review

The review highlights the most relevant recent developments in the field of functional movement disorders (FMD).

Recent findings

The emphasis on making a ‘positive’ diagnosis has driven a renewed interest in assessing the value of simple clinical signs. Furthermore, an effort has been made to develop and test objective diagnostic tools. The association of FMD with several comorbidities is being acknowledged. Pathophysiological understanding has grown with the identification of new neurobiological abnormalities, including a decreased interoceptive sensitivity. Finally – and most importantly – the recognition of the potential benefits of specialized physiotherapy is changing FMD management.

The field of FMD is moving forward on a number of fronts, including diagnosis, pathophysiology, and treatment. A major priority for future research is providing robust evidence regarding treatment.
Urban environment shortens telomere length in nestling great tits,
Parus major
Authors: Salmón P. , Nilsson J. F. , Nord A. , Bensch S. , Isaksson C.
Published: June 2016

Urban environments are expanding rapidly, and with urbanization come both challenges and opportunities for wildlife. Challenges include combating the anthropogenic disturbances such as light, noise and air pollution and lower availability of natural food sources. The benefits are many, including the availability of anthropogenic food sources, breeding boxes and warmer temperatures. Thus, depending on the context, urbanization can have both positive and negative effects on fitness related traits. It is well known that early-life conditions can have lifelong implications on fitness; little is however known about development in urban environments. We reciprocally cross-fostered urban and rural nestling great tits (
Parus major
L.) to study how growing up in an urban versus rural habitat affected telomere length (TL)—a suggested biomarker of longevity. We show, for the first time, that growing up in an urban environment significantly shortens TL, independently of natal origin (i.e. urban or rural). This implies that the urban environment imposes a challenge to developing birds, with potentially irreversible effects on lifespan.
On the impact of modelling assumptions in multi-scale, subject-specific models of aortic haemodynamics
Authors: Alastruey Jordi , Xiao Nan , Fok Henry , Schaeffter Tobias , Figueroa C. Alberto
Published: June 2016

Simulation of haemodynamics has become increasingly popular within the research community. Irrespective of the modelling approach (zero-dimensional (0D), one-dimensional (1D) or three-dimensional (3D)),
in vivo
measurements are required to personalize the arterial geometry, material properties and boundary conditions of the computational model. Limitations in
in vivo
data acquisition often result in insufficient information to determine all model parameters and, hence, arbitrary modelling assumptions. Our goal was to minimize and understand the impact of modelling assumptions on the simulated blood pressure, flow and luminal area waveforms by studying a small region of the systemic vasculature—the upper aorta—and acquiring a rich array of non-invasive magnetic resonance imaging and tonometry data from a young healthy volunteer. We first investigated the effect of different modelling assumptions for boundary conditions and material parameters in a 1D/0D simulation framework. Strategies were implemented to mitigate the impact of inconsistencies in the
in vivo
data. Average relative errors smaller than 7% were achieved between simulated and
in vivo
waveforms. Similar results were obtained in a 3D/0D simulation framework using the same inflow and outflow boundary conditions and consistent geometrical and mechanical properties. We demonstrated that accurate subject-specific 1D/0D and 3D/0D models of aortic haemodynamics can be obtained using non-invasive clinical data while minimizing the number of arbitrary modelling decisions.
Intermittent turbulence in flowing bacterial suspensions
Authors: Secchi Eleonora , Rusconi Roberto , Buzzaccaro Stefano , Salek M. Mehdi , Smriga Steven , Piazza Roberto , Stocker Roman
Published: June 2016

Dense suspensions of motile bacteria, possibly including the human gut microbiome, exhibit collective dynamics akin to those observed in classic, high Reynolds number turbulence with important implications for chemical and biological transport, yet this analogy has remained primarily qualitative. Here, we present experiments in which a dense suspension of
Bacillus subtilis
bacteria was flowed through microchannels and the velocity statistics of the flowing suspension were quantified using a recently developed velocimetry technique coupled with vortex identification methods. Observations revealed a robust intermittency phenomenon, whereby the average velocity profile of the suspension fluctuated between a plug-like flow and a parabolic flow profile. This intermittency is a hallmark of the onset of classic turbulence and Lagrangian tracking revealed that it here originates from the presence of transient vortices in the active, collective motion of the bacteria locally reinforcing the externally imposed flow. These results link together two entirely different manifestations of turbulence and show the potential of the microfluidic approach to mimic the environment characteristic of certain niches of the human microbiome.
How far will a behaviourally flexible invasive bird go to innovate?
Authors: Logan Corina J.
Published: June 2016

Behavioural flexibility is considered a key factor in the ability to adapt to changing environments. A traditional way of characterizing behavioural flexibility is to determine whether individuals invent solutions to novel problems, termed innovativeness. Great-tailed grackles are behaviourally flexible in that they can change their preferences when a task changes using existing behaviours; however, it is unknown how far they will go to invent solutions to novel problems. To begin to answer this question, I gave grackles two novel tests that a variety of other species can perform: stick tool use and string pulling. No grackle used a stick to access out-of-reach food, even after seeing a human demonstrate the solution. No grackle spontaneously pulled a vertically oriented string, but one did pull a horizontally oriented string twice. Additionally, a third novel test was previously conducted on these individuals and it was found that no grackle spontaneously dropped stones down a platform apparatus to release food, but six out of eight did become proficient after training. These results support the idea that behavioural flexibility is a multi-faceted trait because grackles are flexible, but not particularly innovative. This contradicts the idea that behavioural flexibility and innovativeness are interchangeable terms.
A stochastic two-scale model for pressure-driven flow between rough surfaces
Authors: Pérez-Ràfols Francesc , Larsson Roland , Lundström Staffan , Wall Peter , Almqvist Andreas
Published: June 2016

Seal surface topography typically consists of global-scale geometric features as well as local-scale roughness details and homogenization-based approaches are, therefore, readily applied. These provide for resolving the global scale (large domain) with a relatively coarse mesh, while resolving the local scale (small domain) in high detail. As the total flow decreases, however, the flow pattern becomes tortuous and this requires a larger local-scale domain to obtain a converged solution. Therefore, a classical homogenization-based approach might not be feasible for simulation of very small flows. In order to study small flows, a model allowing feasibly-sized local domains, for really small flow rates, is developed. Realization was made possible by coupling the two scales with a stochastic element. Results from numerical experiments, show that the present model is in better agreement with the direct deterministic one than the conventional homogenization type of model, both quantitatively in terms of flow rate and qualitatively in reflecting the flow pattern.
Dynamics of atmospheres with a non-dilute condensible component
Authors: Pierrehumbert Raymond T. , Ding Feng
Published: June 2016

The diversity of characteristics for the host of recently discovered exoplanets opens up a great deal of fertile new territory for geophysical fluid dynamics, particularly when the fluid flow is coupled to novel thermodynamics, radiative transfer or chemistry. In this paper, we survey one of these new areas—the climate dynamics of atmospheres with a non-dilute condensible component, defined as the situation in which a condensible component of the atmosphere makes up a substantial fraction of the atmospheric mass within some layer. Non-dilute dynamics can occur for a wide range of condensibles, generically applying near both the inner and the outer edges of the conventional habitable zone and in connection with runaway greenhouse phenomena. It also applies in a wide variety of other planetary circumstances. We first present a number of analytical results developing some key features of non-dilute atmospheres, and then show how some of these features are manifest in simulations with a general circulation model adapted to handle non-dilute atmospheres. We find that non-dilute atmospheres have weak horizontal temperature gradients even for rapidly rotating planets, and that their circulations are largely barotropic. The relative humidity of the condensible component tends towards 100% as the atmosphere becomes more non-dilute, which has important implications for runaway greenhouse thresholds. Non-dilute atmospheres exhibit a number of interesting organized convection features, for which there is not yet any adequate theoretical understanding.
On nonlinear thermo-electro-elasticity
Authors: Mehnert Markus , Hossain Mokarram , Steinmann Paul
Published: June 2016

Electro-active polymers (EAPs) for large actuations are nowadays well-known and promising candidates for producing sensors, actuators and generators. In general, polymeric materials are sensitive to differential temperature histories. During experimental characterizations of EAPs under electro-mechanically coupled loads, it is difficult to maintain constant temperature not only because of an external differential temperature history but also because of the changes in internal temperature caused by the application of high electric loads. In this contribution, a thermo-electro-mechanically coupled constitutive framework is proposed based on the total energy approach. Departing from relevant laws of thermodynamics, thermodynamically consistent constitutive equations are formulated. To demonstrate the performance of the proposed thermo-electro-mechanically coupled framework, a frequently used non-homogeneous boundary-value problem, i.e. the extension and inflation of a cylindrical tube, is solved analytically. The results illustrate the influence of various thermo-electro-mechanical couplings.
Multigenerational exposure to silver ions and silver nanoparticles reveals heightened sensitivity and epigenetic memory inCaenorhabditis elegans
Authors: Schultz Carolin L. , Wamucho Anye , Tsyusko Olga V. , Unrine Jason M. , Crossley Alison , Svendsen Claus , Spurgeon David J.
Published: June 2016

The effects from multigenerational exposures to engineered nanoparticles (ENPs) in their pristine and transformed states are currently unknown despite such exposures being an increasingly common scenario in natural environments. Here, we examine how exposure over 10 generations affects the sensitivity of the nematodeCaenorhabditis elegansto pristine and sulfidized Ag ENPs and AgNO3. We also include populations that were initially exposed over six generations but kept unexposed for subsequent four generations to allow recovery from exposure. Toxicity of the different silver forms decreased in the order AgNO3, Ag ENPs and Ag2S ENPs. Continuous exposure to Ag ENPs and AgNO3caused pronounced sensitization (approx. 10-fold) in the F2 generation, which was sustained until F10. This sensitization was less pronounced for Ag2S ENP exposures, indicating different toxicity mechanisms. Subtle changes in size and lifespan were also measured. In the recovery populations, the sensitivity to Ag ENPs and AgNO3resulting from the initial multigenerational exposure persisted. Their response sensitivity for all endpoints was most closely related to the last ancestral exposed generation (F5), rather than unexposed controls. The mechanisms of transgenerational transfer of sensitivity are probably organized through the epigenome, and we encourage others to investigate such effects as a priority for mechanistic toxicology.
A novel function of calcitonin gene-related peptide in body fluid Cl−homeostasis
Authors: Wang Yi-Fang , Lafont Anne-Gaëlle , Lee Yi-Chun , Hwang Pung-Pung
Published: June 2016

Vertebrates need to maintain extracellular chloride (Cl−) concentrations to ensure the normal operation of physiological processes; the transition from aquatic to terrestrial environments necessitated the development of sophisticated mechanisms to ensure Cl−homeostasis in the face of fluctuating Cl−levels. Zebrafish calcitonin gene-related peptide (CGRP), unlike its splice variant calcitonin, does not respond to environmental Ca2+levels. This study aimed to test the hypothesis that CGRP is involved in the control of body fluid Cl−homeostasis. Acclimation to high-Cl−artificial water stimulated the mRNA expression ofcgrpand the receptor (crlr1) when compared with low-Cl−. CGRP knockdown induced upregulation of the Na+-Cl−co-transporter (ncc2b), while overexpression of CGRP resulted in the downregulation ofncc2bmRNA synthesis and a simultaneous decrease in Cl−uptake in embryos. Consistent with these findings, knockdown of eithercgrporcrlr1was found to increase the density of NCC2b-expressing cells in embryos. This is the first demonstration that CGRP acts as a hypochloremic hormone through suppressing NCC2b expression and the differentiation of NCC-expressing ionocytes. Elucidation of this novel function of CGRP in fish body fluid Cl−homeostasis promises to enhance our understanding of the related physiology in vertebrates.
Vision and locomotion shape the interactions between neuron types in mouse visual cortex
Authors: Dipoppa Mario , Ranson Adam , Krumin Michael , Pachitariu Marius , Carandini Matteo , Harris Kenneth D
Published: June 2016

In the mouse primary visual cortex (V1), sensory responses are shaped by behavioral factors such as locomotion. These factors are thought to control a disinhibitory circuit, whereby interneurons expressing vasoactive intestinal peptide (Vip) inhibit those expressing somatostatin (Sst), disinhibiting pyramidal cells (Pyr). We measured the effect of locomotion on these neurons and on interneurons expressing parvalbumin (Pvalb) in layer 2/3 of mouse V1, and found in-consistencies with the disinhibitory model. In the presence of large stimuli, locomotion increased Sst cell responses without suppressing Vip cells. In the presence of small stimuli, locomotion increased Vip cell responses without suppressing Sst cells. A circuit model could reproduce each cell type’s activity from the measured activity of other cell types, but only if we allowed locomotion to increase feedforward synaptic weights while modulating recurrent weights. These results suggest that locomotion alters cortical function by changing effective synaptic connectivity, rather than only through disinhibition.
Post-selection Inference Following Aggregate Level Hypothesis Testing in Large Scale Genomic Data
Authors: Heller Ruth , Chatterjee Nilanjan , Krieger Abba , Shi Jianxin
Published: June 2016

In many genomic applications, hypotheses tests are performed by aggregating test-statistics across units within naturally defined classes for powerful identification of signals. Following class-level testing, it is naturally of interest to identify the lower level units which contain true signals. Testing the individual units within a class without taking into account the fact that the class was selected using an aggregate-level test-statistic, will produce biased inference. We develop a hypothesis testing framework that guarantees control for false positive rates conditional on the fact that the class was selected. Specifically, we develop procedures for calculating unit level p-values that allows rejection of null hypotheses controlling for two types of conditional error rates, one relating to family wise rate and the other relating to false discovery rate. We use simulation studies to illustrate validity and power of the proposed procedure in comparison to several possible alternatives. We illustrate the power of the method in a natural application involving whole-genome expression quantitative trait loci (eQTL) analysis across 17 tissue types using data from The Cancer Genome Atlas (TCGA) Project.
Structural changes following the reversal of a Y Chromosome to an autosome inDrosophila pseudoobscura
Authors: Chang Ching-Ho , Larracuente Amanda M.
Published: June 2016

Robertsonian translocations resulting in fusions between sex chromosomes and autosomes shape karyotype evolution in animals by creating new sex chromosomes from autosomes. These translocations can also reverse sex chromosomes back into autosomes, which is especially intriguing given that autosomes and sex chromosomes differ in gene regulation and chromatin environment. While researchers are beginning to understand X chromosomes reversals to autosomes at a genomic level, it is difficult to study reversals of Y chromosomes because of their rapid sequence turnover and high repeat content. To gain insight into the genomic events following a Y chromosome reversal, we investigated an autosome-Y translocation in a well-studied and tractable organism,Drosophila pseudoobscura. About 10-15 Mya, the ancestral Y chromosome fused to a small autosome (the dot chromosome) in an ancestor ofD. pseudoobscura. We used single molecule real-time sequencing reads to assemble the genic part of theD. pseudoobscuradot chromosome, including this Y-to-dot translocation. We find that the intervening sequence between the ancestral Y and the rest of the dot chromosome is only ~78 Kb and has a low repeat density, suggesting that the centromere now falls outside, rather than between, the fused chromosomes. The Y-to-dot region is 100 times smaller than theD. melanogasterY chromosome, owing to repeat landscape changes. Previous studies suggest that recurrent selective sweeps favoring shorter introns helped to shrink the Y-to-dot following the translocation. Our results suggest that genetic drift and a small ancestral Y chromosome may also help explain the compact size of the Y-to-dot translocation.
A cell type-specific expression signature predicts haploinsufficient autism-susceptibility genes
Authors: Zhang Chaolin , Shen Yufeng
Published: June 2016

Recent studies have identified many genes with rarede novomutations in autism, but a limited number of these have been conclusively established as disease-susceptibility genes due to lack of recurrence and confounding background mutations. Such extreme genetic heterogeneity severely limits recurrence-based statistical power even in studies with a large sample size. In addition, the cellular contexts in which these genomic lesions confer disease risks remain poorly understood. Here we investigate the use of cell-type specific expression profiles to differentiate mutations in autism patients or unaffected siblings. Using 24 distinct cell types isolated from the mouse central nervous system, we identified an expression signature shared by genes with likely gene disrupting (LGD) mutations detected by exome-sequencing in autism cases. The signature reflects haploinsufficiency of risk genes enriched in transcriptional and post-transcriptional regulators, with the strongest positive associations with specific types of neurons in different brain regions, including cortical neurons, cerebellar granule cells, and striatal medium spiny neurons. Based on this signature, we assigned a D score to all human genes to prioritize candidate autism-susceptibility genes. When applied to genes with only a single LGD mutation in cases, the D score achieved a precision of 40% as compared to the 15% baseline with a minimal loss in sensitivity. Further improvement was made by combining D score and mutation intolerance metrics from ExAC which were derived from orthogonal data sources. The ensemble model achieved precision of 60% and predicted 117 high-priority candidates. These prioritized lists can facilitate identification of additional autism-susceptibility genes.
A Polymer Model with Epigenetic Recolouring Reveals a Pathway for thede novoEstablishment and 3D organisation of Chromatin Domains
Authors: Michieletto D. , Orlandini E. , Marenduzzo D.
Published: June 2016

One of the most important problems in development is how epigenetic domains can be first established, and then maintained, within cells. To address this question, we propose a framework which couples 3D chromatin folding dynamics, to a “recolouring” process modeling the writing of epigenetic marks. Because many intra-chromatin interactions are mediated by bridging proteins, we consider a “two-state” model with self-attractive interactions between two epigenetic marks which are alike (either active or inactive). This model displays a first-order-like transition between a swollen, epigenetically disordered, phase, and a compact, epigenetically coherent, chromatin globule. If the self-attraction strength exceeds a threshold, the chromatin dynamics becomes glassy, and the corresponding interaction network freezes. By modifying the epigenetic read-write process according to more biologically-inspired assumptions, our polymer model with recolouring recapitulates the ultrasensitive response of epigenetic switches to perturbations, and accounts for long-lived multi-domain conformations, strikingly similar to the topologically-associating-domains observed in eukaryotic chromosomes.
Long-term, layer-specific reverberant activity in the mouse somatosensory cortex following sensory stimulation
Authors: Phoka Elena , Berditchevskaia Aleksandra , Barahona Mauricio , Schultz Simon R
Published: June 2016

Neocortical circuits exhibit spontaneous neuronal activity whose functional relevance remains enigmatic. Several proposed functions assume that sensory experience can influence subsequent spontaneous activity. However, long-term alterations in spontaneous firing rates following sensory stimulation have not been reported until now. Here we show that multi-whisker, spatiotemporally rich stimulation of mouse vibrissae induces a laminar-specific, long-term increase of spontaneous activity in the somatosensory cortex. Such stimulation additionally produces stereotypical neural ensemble firing patterns from simultaneously recorded single neurons, which are maintained during spontaneous activity following stimulus offset. The increased neural activity and concomitant ensemble firing patterns are sustained for at least 25 minutes after stimulation, and specific to layers IV and Vb. In contrast, the same stimulation protocol applied to a single whisker fails to elicit this effect. Since layer Vb has the largest receptive fields and, together with layer IV, receives direct thalamic and lateral drive, the increase in firing activity could be the result of mechanisms involving the integration of spatiotemporal patterns across multiple whiskers. Our results provide direct evidence of modification of spontaneous cortical activity by sensory stimulation and could offer insight into the role of spatiotemporal integration in memory storage mechanisms for complex stimuli.
Gene tree discordance generates patterns of diminishing convergence over time
Authors: Mendes Fabio K. , Hahn Yoonsoo , Hahn Matthew W.
Published: June 2016

Phenotypic convergence is an exciting outcome of adaptive evolution, occurring when species find similar solutions to the same problem. Unraveling the molecular basis of convergence provides a way to link genotype to adaptive phenotypes, but can also shed light on the extent to which evolution is repeatable and predictable. Many recent genome-wide studies have uncovered a striking pattern of diminishing convergence over time, ascribing this pattern to the presence of intramolecular epistatic interactions. Here, we consider gene tree discordance as an alternative driver of convergence levels over time. We demonstrate that gene tree discordance can produce patterns of diminishing convergence by itself, and that controlling for discordance as a cause of apparent convergence makes the pattern disappear. We also show that synonymous substitutions, where neither selection nor epistasis should be prevalent, have the same diminishing pattern of molecular convergence among closely related primate species. Finally, we demonstrate that even in situations where biological discordance is not possible, errors in species tree inference can drive these same patterns. Though intramolecular epistasis is undoubtedly affecting many proteins, our results suggest an additional explanation for this widespread pattern. These results contribute to a growing appreciation not just of the presence of gene tree discordance, but of the unpredictable effects this discordance can have on analyses of molecular evolution.
Multikernel linear mixed models for complex phenotype prediction
Authors: Weissbrod Omer , Geiger Dan , Rosset Saharon
Published: June 2016

Linear mixed models (LMMs) and their extensions have recently become the method of choice in phenotype prediction for complex traits. However, LMM use to date has typically been limited by assuming simple genetic architectures. Here, we present multikernel linear mixed model (MKLMM), a predictive modeling framework that extends the standard LMM using multiple-kernel machine learning approaches. MKLMM can model genetic interactions and is particularly suitable for modeling complex local interactions between nearby variants. We additionally present MKLMM-Adapt, which automatically infers interaction types across multiple genomic regions. In an analysis of eight case-control data sets from the Wellcome Trust Case Control Consortium and more than a hundred mouse phenotypes, MKLMM-Adapt consistently outperforms competing methods in phenotype prediction. MKLMM is as computationally efficient as standard LMMs and does not require storage of genotypes, thus achieving state-of-the-art predictive power without compromising computational feasibility or genomic privacy.
Multi-speckle X-ray photon correlation spectroscopy in the ultra-small-angle X-ray scattering range
Authors: Möller Johannes , Chushkin Yuriy , Prevost Sylvain , Narayanan Theyencheri
Published: June 2016

Multi-speckle X-ray photon correlation spectroscopy (XPCS) measurements in the ultra-small-angle range are performed using a long pinhole collimation instrument in combination with two-dimensional photon-counting and high-sensitivity imaging detectors. The feasibility of the presented setup to measure dynamics on different time and length scales pertinent to colloidal systems is shown. This setup offers new research opportunities, such as for example in the investigation of non-equilibrium dynamics in optically opaque, complex systems over length scales from tens of nanometres to several micrometres. In addition, due to the short duration of the X-ray exposure involved in the ultra-small-angle range, possible radiation-induced effects are alleviated. Furthermore, the performance of two different detectors, a photon-counting Pilatus 300K and an integrating FReLoN CCD, are compared, and their applicability for accurate XPCS measurements is demonstrated.
VanadiumK-edge XANES in vanadium-bearing model compounds: a full multiple scattering study
Authors: Benzi Federico , Giuli Gabriele , Della Longa Stefano , Paris Eleonora
Published: June 2016

A systematic study is presented on a set of vanadium-bearing model compounds, representative of the most common V coordination geometries and oxidation states, analysed by means of vanadiumK-edge X-ray absorption near-edge spectroscopy calculations in the full multiple scattering (FMS) framework. Analysis and calibration of the free parameters of the theory under the muffin-tin approximation (muffin-tin overlap and interstitial potential) have been carried out by fitting the experimental spectra using theMXANprogram. The analysis shows a correlation of the fit parameters with the V coordination geometry and oxidation state. By making use of this correlation it is possible to approach the study of unknown V-bearing compounds with useful preliminary information.
Veet: facing a cultural challenge in Pakistan
Authors: Husain Saima , Naheed Kanza , Isa Mahrukh
Published: June 2016

Subject area

This case has been written after extensive field research. It is designed specifically for the International Marketing course. However, it can be used in Brand Management, Consumer Behavior and Marketing Management courses as well.

Study level/applicability

Final-year BBA students or first-year MBA students.

Case overview

Although introduced in Pakistan in 1999, Veet, a personal hygiene brand, has failed to realize its potential even after a decade. Pakistan is a conservative society and women feel embarrassed buying hair-removing creams. Humayun Farooq, the new brand manager, is at a crossroad; he believes in giving the brand a bold take-off by using fashion as a platform, whereas both top management and his assistant brand manager are skeptical of his proposition, as they see it as risky. His decision is critical, as there is pressure to strike a balance between global standardization and local cultural norms.

Expected learning outcomes

The students will be able to: understand how global brands need to conceptualize and implement local brand strategies, given the different market challenges; and apply key theoretical concepts in International Marketing such as cultural product adaptation.

Supplementary materials

Instructors must ask the students to study the following before discussing the case in class. For the on-air 2009 advertisement of Veet in Pakistan, visit: www.youtube.com/watch?v=8Va9bA-ebqE. Although the case sheds light on the relevant Pakistani cultural and religious norms, students may further research and study the Pakistani culture. Nijssen, E.J. and Douglas, S.P. (2011). “World World-mindedness and attitudes toward product positioning in advertising: an examination of global versus foreign versus local positioning”, Journal of International Marketing, Vol. 19 No. 3, pp. 113-133. Shivkumar, H. (2006), Managing global brand advertising, World Advertising Research Centre.

Subject code

CSS 8: Marketing
Raman spectroscopy characterization of hypo-eutectic CoCrWC alloy tribolayers
Authors: Motallebzadeh Amir , Atar Erdem , Cimenoglu Huseyin
Published: June 2016

Purpose

This paper aims to study microstructure and high temperature tribological performance of hypo-eutectic CoCrWC hardfacing alloy (Stellite 12) deposited on steel substrate by plasma-transferred arc (PTA) welding technique.

Design/methodology/approach

Microstructural characterization of the deposited coating was made using electron probe microanalysis, X-ray diffraction and microhardness tester. Dry sliding wear tests were carried out with a ball-on-disc type tribometer at room and elevated temperature. Worn surfaces of the samples were examined by the EDX equipped SEM and Raman spectroscopy.

Findings

Results revealed that at room temperature and 300°C plasticity dominated wear mechanism was operative. Under oxidation dominated wear conditions (400, 500, 600 and 700°C), testing temperature plays a crucial role on the characteristics of the oxide tribolayers formed on worn surfaces. Development of Cr2O3 in the tribolayer at 600 and 700°C was beneficial in increasing wear resistance of examined coating.

Originality/value

While the sliding wear performance of Stellite alloys at room temperature has been investigated in details, published studies on tribological behavior of Stellite alloys with varying temperature are scarce. Therefore, the present work was undertaken to study the wear mechanisms and the type of tribolayers formed during sliding wear of PTA welding deposited hypo-eutectic Stellite 12 coating with increasing temperature up to 700°C.
Effect of argon plasma surface modification on tribological behavior of biopolymers
Authors: Sagbas Binnur
Published: June 2016

Purpose

The aim of this study is to determine the effect of argon plasma surface modification on tribological properties of conventional ultra-high molecular weight polyethylene (UHMWPE) and vitamin E-blended UHMWPE. In previous studies, some researchers conducted a study on argon plasma surface modification of UHMWPE, but there is no study about argon plasma surface modification of VE-UHMWPE. So another objective of this paper is to compare the results for both the material groups.

Design/methodology/approach

UHMWPE and vitamin E-blended UHMWPE sample surfaces were modified by microwave-induced argon plasma to increase tribological properties of the materials. The modified surfaces were evaluated in terms of wettability and wear behavior. Wettability of the surfaces was determined by contact angle measurements. Wear behavior was examined by ball-on-disc wear tests under lubrication with 25 per cent bovine serum.

Findings

Argon plasma surface modification enhanced the wear resistance and surface wettability properties of conventional UHMWPE and VE-UHMWPE. Wear factor of argon plasma-treated samples reduced, but for VE-UHMWPE samples, this reduction was not as high as the conventional UHMWPE’s wear factor.

Originality/value

In previous studies, some researchers have studied on argon plasma surface modification of UHMWPE, but there is no study about argon plasma surface modification of VE-UHMWPE.
Absenteeism and performance in a quantitative module A quantile regression analysis
Authors: Pani Pranab Kumar , Kishore Pallavi
Published: June 2016

Purpose

– There is growing evidence that learning is faster, measurably better and more productive in a classroom setting when a student attends classes regularly. Each student brings in his/her experience, skills, and unique learning styles to a class – thus a classroom environment can potentially create positive externalities through which a student can gain substantially from various strengths of his/her peers. However, students do remain absent from their classes for a variety of reasons. One of the measurable effects of regular non-attendance in a university class, where students from various cultures and regions interact, is the academic performance. The purpose of this paper is to determine if there is any potential causal link between absenteeism (attendance) and academic performance.

Design/methodology/approach

– Data were culled from the records of three batches of students in a British university campus in the Middle East. Quantile regression methods were used to establish the causal relationship between absenteeism and academic performance.

Findings

– A quantile regression analysis reveals that absenteeism has negative impact on academic performance. This also suggests that low performers are worse affected by absenteeism as compared to the high performers.

Research limitations/implications

– Inclusion of some other factors, such as study habits, additional hours spent on quantitative modules, student’s ethnicity background, particularly in the context of United Arab Emirates, could have emboldened the robustness of the study. Non-availability or paucity of this information, to some degree, has limited the conclusions of this study.

Originality/value

– Proponents of mandatory attendance argue that there is a positive correlation between attendance and performance. But, one very important issue which gets overlooked is who actually benefits more by attending classes – are the shirkers who have a poor attendance record or the ones who are more sincere, more regular, and active participants in a class? This study uses quantile regression analysis to address this issue.
Strategic CSR: an integrative model for analysis
Authors: Marques-Mendes António , Santos Maria João
Published: June 2016

Purpose

Based on an extensive review of the literature, the purpose of this paper is to propose an analytical model that enables the study of the corporate social responsibility (CSR)’s strategic orientation of companies through the analysis of: the different types of CSR integration into company strategies; the different levels of CSR strategic maturity; and the path necessary to be followed for a company to achieve its full development and correspondingly forecasting which initiatives hold the greatest contribution toward this end.

Design/methodology/approach

This paper sets out a conceptual framework, which was drafted building on an extensive critical review of the literature seeking to incorporate the diverse contributions made by the existing CSR models and classifications.

Findings

The analytical framework here proposed enables a wide reaching approach to analyzing strategic CSR, their underlying motivations and its core factors. It also extends to considering the different phases of maturity enabling the evaluation of the distinctive levels of CSR integration into the company strategy and the stage at which the company currently stands at on its determined path.

Practical implications

From a practical perspective, the suggested framework enables practitioners to access a practical tool that specifically measures their companies’ CSR maturity and strategic profile and which may serve as well as a means of diagnosis, improvement or of adaptation.

Originality/value

This model of analysis generates the identification of the factors explaining the different levels of CSR integration into the company strategy and evaluating the level of maturity prevailing.
Estimating the hidden corporate social performance of Japanese firms
Authors: Suto Megumi , Takehara Hitoshi
Published: June 2016

Purpose

Managers sometimes hide their level of corporate social performance (CSP) from investors, intentionally or unintentionally. The purpose of this study is to estimate such “hidden CSP” of firms.

Design/methodology/approach

In this study, it is assumed that Japanese public firms can be classified into two groups based on the difference in corporate social responsibility (CSR) awareness. Thus, the respondents to the CSR questionnaire survey are classified as the CSR-aware group, and the non-respondents are treated as the CSR-unaware group. It is further assumed that a significant relationship exists between CSP and a firm’s attributes, including financial performance and stock ownership. Under these assumptions, a model to estimate the CSP of non-respondents is constructed using the relationship between CSP and a firm’s observable attributes.

Findings

There is a significant latent gap between the CSP of respondents and the hidden CSP of non-respondents because of differences in firm size, foreign dependency of business and reputation and trust in the financial markets, rather than because of differences in financial performance. Insider-oriented ownership structures are negatively associated with CSP.

Research limitations/implications

The estimation model developed in this study depends on a set of assumptions. In particular, a stable relationship between CSP and firm-specific variables, i.e. there is no structural change during the observation period, is assumed. Despite these limitations, this study extends the CSR research perspective, as it makes it possible to estimate the hidden CSP of public firms.

Practical implications

In practice, the findings of this study surface a part of the missing CSR that investors need and that could alert non-respondent firms to the importance of CSR strategy and related disclosures to adapt to rapidly changing social and environmental business settings.

Originality/value

This study is the result of academic interest in examining the missing information related to CSR activities to obtain an overall picture of the CSP distribution of Japanese listed firms as a whole.
Linguistic perception of corporate responsibility disclosure: the case of Japanese Idemitsu
Authors: Hossein Rahdari Amir , Braendle Udo
Published: June 2016

Purpose

This paper aims to examine a case to illustrate the linguistic perception of corporate responsibility disclosures.

Design/methodology/approach

In this study, a content analysis framework based on fuzzy linguistic variables is proposed to measure the level of sustainable and responsible practices perceived by the stakeholders. A case is examined to illustrate the linguistic perception of corporate responsibility disclosures.

Findings

The results demonstrated a significant difference between Perception of Disclosure, using linguistic variables and most common sustainability indicators, and a Boolean analysis based on sustainability reporting indicators. The approach helps companies in developing a more robust stakeholder management program and to better respond to stakeholders’ demands.

Research limitations/implications

Future studies can evaluate corporate responsibility and sustainability performance using linguistic variables.

Practical implications

The approach helps companies to better respond to stakeholders’ demands.

Social implications

The approach helps companies in developing a more robust stakeholder management program and to better respond to stakeholders’ demands.

Originality/value

Most of the studies on corporate responsibility disclosure analysis have focused on a binary response to the level of disclosure of a certain economic, social, environmental or governance issue; however, how a disclosed item is being perceived by the user has not been taken into consideration.