bluuebunny/crossref_metadata_2025 huggingface dataset:
Postnatal ontogeny and the evolution of macrostomy in snakes
Authors: Scanferla Agustín
Published: November 2016

Macrostomy is the anatomical feature present in macrostomatan snakes that permits the ingestion of entire prey with high cross-sectional area. It depends on several anatomical traits in the skeleton and soft tissues, of which the elongation of gnathic complex and backward rotation of the quadrate represent crucial skeletal requirements. Here, the relevance of postnatal development of these skull structures and their relationship with macrohabitat and diet are explored. Contrary to the condition present in lizards and basal snakes that occupy underground macrohabitats, elements of the gnathic complex of most macrostomatan snakes that exploit surface macrohabitats display conspicuous elongation during postnatal growth, relative to the rest of the skull, as well as further backward rotation of the quadrate bone. Remarkably, several clades of small cryptozoic macrostomatans reverse these postnatal transformations and return to a diet based on prey with low cross-sectional area such as annelids, insects or elongated vertebrates, thus resembling the condition present in underground basal snakes. Dietary ontogenetic shift observed in most macrostomatan snakes is directly linked with this ontogenetic trajectory, indicating that this shift is acquired progressively as the gnathic complex elongates and the quadrate rotates backward during postnatal ontogeny. The numerous independent events of reversion in the gnathic complex and prey type choice observed in underground macrostomatans and the presence of skeletal requirements for macrostomy in extinct non-macrostomatan species reinforce the possibility that basal snakes represent underground survivors of clades that had the skeletal requirements for macrostomy. Taken together, the data presented here suggest that macrostomy has been shaped during multiple episodes of occupation of underground and surface macrohabitats throughout the evolution of snakes.
The world's biomes and primary production as a triple tragedy of the commons foraging game played among plants
Authors: McNickle Gordon G. , Gonzalez-Meler Miquel A. , Lynch Douglas J. , Baltzer Jennifer L. , Brown Joel S.
Published: November 2016

Plants appear to produce an excess of leaves, stems and roots beyond what would provide the most efficient harvest of available resources. One way to understand this overproduction of tissues is that excess tissue production provides a competitive advantage. Game theoretic models predict overproduction of all tissues compared with non-game theoretic models because they explicitly account for this indirect competitive benefit. Here, we present a simple game theoretic model of plants simultaneously competing to harvest carbon and nitrogen. In the model, a plant's fitness is influenced by its own leaf, stem and root production, and the tissue production of others, which produces a triple tragedy of the commons. Our model predicts (i) absolute net primary production when compared with two independent global datasets; (ii) the allocation relationships to leaf, stem and root tissues in one dataset; (iii) the global distribution of biome types and the plant functional types found within each biome; and (iv) ecosystem responses to nitrogen or carbon fertilization. Our game theoretic approach removes the need to define allocation or vegetation type
a priori
but instead lets these emerge from the model as evolutionarily stable strategies. We believe this to be the simplest possible model that can describe plant production.
Microscopic and immunohistochemical analyses of the claw of the nesting dinosaur,
Citipati osmolskae
Authors: Moyer Alison E. , Zheng Wenxia , Schweitzer Mary H.
Published: November 2016

One of the most well-recognized Cretaceous fossils is
Citipati osmolskae
(MPC-D 100/979), an oviraptorid dinosaur discovered in brooding position on a nest of unhatched eggs. The original description refers to a thin lens of white material extending from a manus ungual, which was proposed to represent original keratinous claw sheath that, in life, would have covered it. Here, we test the hypothesis that this exceptional morphological preservation extends to the molecular level. The fossil sheath was compared with that of extant birds, revealing similar morphology and microstructural organization. In living birds, the claw sheath consists primarily of two structural proteins; alpha-keratin, expressed in all vertebrates, and beta-keratin, found only in reptiles and birds (sauropsids). We employed antibodies raised against avian feathers, which comprise almost entirely of beta-keratin, to demonstrate that fossil tissues respond with the same specificity, though less intensity, as those from living birds. Furthermore, we show that calcium chelation greatly increased antibody reactivity, suggesting a role for calcium in the preservation of this fossil material.
Stability and plasticity of contextual modulation in the mouse visual cortex
Authors: Ranson Adam
Published: November 2016

Activity of neurons in primary sensory cortex is shaped by visual and behavioural context. However the long-term stability of the influence of contextual factors in the mature cortex remains poorly understood. To investigate this we used 2-photon calcium imaging to track the influence of surround suppression and locomotion on individual neurons over 14 days. We found that highly active excitatory neurons and PV+ interneurons exhibited relatively stable modulation by visual context. Similarly most neurons exhibited a stable yet distinct degree modulation by locomotion. In contrast less active excitatory neurons exhibited plasticity in visual context influence resulting in increased suppression. These findings suggest that the mature visual cortex possesses stable subnetworks of neurons, differentiated by cell-type and activity level, which have distinctive and stable interactions with sensory and behavioural context, as well as other less active and more labile neurons which are sensitive to visual experience.
Origin and Evolution of a Pandemic Lineage of the Kiwifruit PathogenPseudomonas syringaepv.actinidiae
Authors: McCann Honour C. , Li Li , Liu Yifei , Li Dawei , Hui Pan , Zhong Canhong , Rikkerink Erik , Templeton Matthew , Straub Christina , Colombi Elena , Rainey Paul B. , Huang Hongwen
Published: November 2016

Recurring epidemics of kiwifruit (Actinidiaspp.) bleeding canker disease are caused byPseudomonas syringaepv.actinidiae(Psa), whose emergence coincided with domestication of its host. The most recent pandemic has had a deleterious effect on kiwifruit production worldwide. In order to strengthen understanding of population structure, phylogeography and evolutionary dynamics ofPsa, we sampled 746Pseudomonasisolates from cultivated and wild kiwifruit across six provinces in China, of which 87 werePsa. Of 234Pseudomonasisolated from wildActinidiaspp. none were identified asPsa. Genome sequencing of fifty isolates and the inclusion of an additional thirty from previous studies show that China is the origin of the recently emerged pandemic lineage. However China harbours only a fraction of globalPsadiversity, with greatest diversity found in Korea and Japan. Distinct transmission events were responsible for introduction of the pandemic lineage ofPsainto New Zealand, Chile and Europe. Two independent transmission events occurred between China and Korea, and two Japanese isolates from 2014 cluster with New ZealandPsa. Despite high similarity at the level of the core genome and negligible impact of within-lineage recombination, there has been substantial gene gain and loss even within the single clade from which the global pandemic arose.

SIGNIFICANCE STATEMENT

Bleeding canker disease of kiwifruit caused byPseudomonas syringaepv.actinidiae(Psa) has come to prominence in the last three decades. Emergence has coincided with domestication of the host plant and provides a rare opportunity to understand ecological and genetic factors affecting the evolutionary origins ofPsa. Here, based on genomic analysis of an extensive set of strains sampled from China and augmented by isolates from a global sample, we show, contrary to earlier predictions, that China is not the native home of the pathogen, but is nonetheless the source of the recent global pandemic. Our data identify specific transmission events, substantial genetic diversity and point to non-agricultural plants in either Japan or Korea as home to the source population.
Population Genotype Calling from Low-coverage Sequencing Data
Authors: Huang Lin , Danecek Petr , Bercovici Sivan , Batzoglou Serafim
Published: November 2016

In recent years, several large-scale whole-genome projects sequencing tens of thousands of individuals were completed, with larger studies are underway. These projects aim to provide high-quality genotypes for a large number of whole genomes in a cost-efficient manner, by sequencing each genome at low coverage and subsequently identifying alleles jointly in the entire cohort. Here we present Ref-Reveel, a novel method for large-scale population genotyping. We show that Ref-Reveel provides genotyping at a higher accuracy and higher efficiency in comparison to existing methods by applying our method to one of the largest whole-genome sequencing datasets presently available to the public. We further show that utilizing the resulting genotype panel as references, through the Ref-Reveel framework, greatly improves the ability to call genotypes accurately on newly sequenced genomes. In addition, we present a Ref-Reveel pipeline that is applicable for genotyping of very small datasets. In summary, Ref-Reveel is an accurate, scalable and applicable method for a wide range of genotyping scenarios, and will greatly improves the quality of calling genomic alterations in current and future large-scale sequencing projects.
Measuring the importance of annotation granularity to the detection of semantic similarity between phenotype profiles
Authors: Manda Prashanti , Balhoff James P. , Vision Todd J.
Published: November 2016

In phenotype annotations curated from the biological and medical literature, considerable human effort must be invested to select ontological classes that capture the expressivity of the original natural language descriptions, and finer annotation granularity can also entail higher computational costs for particular reasoning tasks. Do coarse annotations suffice for certain applications? Here, we measure how annotation granularity affects the statistical behavior of semantic similarity metrics. We use a randomized dataset of phenotype profiles drawn from 57,051 taxon-phenotype annotations in the Phenoscape Knowledgebase. We compared query profiles having variable proportions of matching phenotypes to subject database profiles using both pairwise and groupwise Jaccard (edge-based) and Resnik (node-based) semantic similarity metrics, and compared statistical performance for three different levels of annotation granularity: entities alone, entities plus attributes, and entities plus qualities (with implicit attributes). All four metrics examined showed more extreme values than expected by chance when approximately half the annotations matched between the query and subject profiles, with a more sudden decline for pairwise statistics and a more gradual one for the groupwise statistics. Annotation granularity had a negligible effect on the position of the threshold at which matches could be discriminated from noise. These results suggest that coarse annotations of phenotypes, at the level of entities with or without attributes, may be sufficient to identify phenotype profiles with statistically significant semantic similarity.
Neuromodulatory circuit effects onDrosophilafeeding behaviour and metabolism
Authors: Eriksson Anders , Raczkowska Marlena , Navawongse Rapeechai , Choudhury Deepak , Stewart James C. , Tang Yi Ling , Wang Zhiping , Claridge-Chang Adam
Published: November 2016

Animals have evolved to maintain homeostasis in a changing external environment by adapting their internal metabolism and feeding behaviour. Metabolism and behaviour are coordinated by neuromodulation; a number of the implicated neuromodulatory systems are homologous between mammals and the vinegar fly, an important neurogenetic model. We investigated whether silencing fly neuromodulatory networks would elicit coordinated changes in feeding, behavioural activity and metabolism. We employed transgenic lines that allowed us to inhibit broad cellular sets of the dopaminergic, serotonergic, octopaminergic, tyraminergic and neuropeptide F systems. The genetically-manipulated animals were assessed for changes in their overt behavioural responses and metabolism by monitoring eleven parameters: activity; climbing ability; individual feeding; group feeding; food discovery; both fed and starved respiration; fed and starved lipid content; and fed/starved body weight. The results from these 55 experiments indicate that individual neuromodulatory system effects on feeding behaviour, motor activity and metabolism are dissociated.
Predicting the phenotype of Mendelian disease missense mutations using amino acid conservation and protein stability change
Authors: Chavez Maria T. , Perlstein Ethan O.
Published: November 2016

Many Mendelian diseases are caused by recessive, loss-of-function missense mutations. On a gene-by-gene basis, it has been demonstrated that missense mutations cause, among other defects, protein misfolding, protein instability, protein mistransport, which strongly suggests that pathogenic missense mutations do not occur at random positions. Based on those observations, we predicted that Mendelian disease missense mutations are enriched in evolutionarily-conserved amino acids. In a pilot set of 260 Mendelian diseases genes affecting cellular organelles we show that missense mutations indeed occur in amino acids that are significantly more conserved than the average amino acid in the protein based on three different scoring methods (Jensen Shannon Divergence p = 7.78E-03, Shannon Entropy p = 1.68E-13, Sum of Pairs p = 1.55E-17). In order to understand how these results might be related to clinical phenotypes in humans or preclinical phenotypes in model organisms, we calculated the protein stability change upon mutation (ΔΔGu) using EASE-MM and found that, on average, pathogenic mutations cause a stability change of greater magnitude than benign mutations (p = 4.414428E-23). Finally, we performed a computational case study on NPC1, the gene responsible for 95% of diagnosed cases of the lysosomal storage disorder Niemann-Pick Type C using a set of 411 missense mutations from the Exome Aggregation Consortium.
Does corporate governance influence the efficiency of working capital management of listed firms
Authors: Fiador Vera
Published: November 2016

Purpose

The purpose of this paper is to explore the relevance of corporate governance in the quest to attain organizational efficiency in the working capital management of listed firms. There is a consensus that efficiency of working capital management is vital for firm’s growth and survival, yet another consensus is the role of corporate governance in limiting managerial self-serving behavior and ultimately improving firm’s efficiency. If the foregoing views hold, then the empirical question “Is corporate governance important for firm-level working capital efficiency?” becomes important.

Design/methodology/approach

Panel data on 13 non-financial firms listed on the Ghana Stock Exchange were employed in a pooled OLS regression.

Findings

The results of the study indicate mostly a negative effect of internal governance mechanisms on the cash conversion cycle, the inventory, receivables’ periods and payables’ periods, implying that governance structures do affect the efficiency of working capital management. Firm characteristics like age, size and profitability also emerged as relevant influences on the efficiency of working capital management.

Research limitations/implications

Data for the study cut across several sectors thus limiting the specificity with which findings can be applied.

Originality/value

These findings have implications for board composition in the quest for firm-level efficiency while raising the need for more industry-specific enquiries.
Employee participation and turnover intention
Authors: Kumar Manish , Jauhari Hemang
Published: November 2016

Purpose

This paper aims to examine the explanatory roles of organizational justice (OJ) and learning goal/need satisfaction (LGS/LNS) in the relationship between participation in decision-making (PDM) and turnover intention (TI) of employees. OJ was expected to mediate the relationship of PDM with LNS and TI. Further, LNS was expected to mediate the relationship of PDM and OJ with TI.

Design/methodology/approach

This study used a rigorous design with 192 responses collected with temporal separation using snowball sampling technique. Responses on PDM, OJ and LNS were taken at one point of time, whereas responses on TI were taken at another point of time. Analysis was done using structural equation modeling approach in IBM SPSS AMOS 20.

Findings

OJ partially mediates PDM and LNS relationship but fully mediates PDM and TI relationship. Further, LNS partially mediates OJ and TI relationship but fully mediates PDM and TI relationship. PDM does not have a direct effect on TI.

Research limitations/implications

Ensuring participation of employees on programs and policies including those on human resources by itself may not be able to reduce TI of employees. It is when employees are able to experience fairness for themselves and/or they are able to add value for themselves by enhancing relevant knowledge base that PDM has an impact on TI. Therefore, organizations must ensure all three aspects of concern to employees; ensuring participation, fairness and individual growth of the employees to address TI.

Originality/value

Although there are studies relating TI separately with PDM, fairness and satisfaction, this study is able to contribute by specifying two-stage explanatory mechanism between PDM and TI. In addition, the authors believe that this study has brought in so far unexplored nuance of relevance of individual quest for learning in explaining TI. Further, through the use of robust design, the study contributes in corroborating research findings on TI.
Onboarding self-initiated expatriates
Authors: Guðmundsdóttir Svala , Lundbergsdóttir Linda M.
Published: November 2016

Purpose

The purpose of this paper was to explore how Icelandic employees experienced the onboarding process when they started working for the Nordic co-operation.

Design/methodology/approach

A case study methodology was performed, where semi-structured interviews with Icelandic expatriates working for the Nordic co-operation were conducted, along with an open-ended questionnaire to the human resource manager. Relevant internet sites were analyzed along with job postings.

Findings

The results indicate that the Nordic co-operation could do better in relation to onboarding their new employees, particularly, in relation to the practical aspect of relocation. The expatriates reported to be satisfied with the work related onboarding and found a value in having a mentor or assigned individual who would take responsibility of introducing the new employee to work-related aspects.

Research limitations/implications

The number of interviews may be considered small when compared to other expatriate studies. Further, the results can only be considered as a first step in a longer process of mapping the ideal onboarding process for international assignees.

Practical implications

Based on the results, it was recommended that the Nordic co-operation should re-examine their onboarding, particularly, in relation to sharing practical information, and incorporating the spouse into the program, as suggested by a number of studies.

Social implications

By understanding the challenges self-initiated expatriates (SIE) face when taking up a new job in a new country, human resource departments will be in a better position to assist the assignee and family for a smoother transition.

Originality/value

In recent years, research on global carriers has been dominated by expatriate managers who are sent abroad on behalf of their company. However, far less is known about SIE and their onboarding process from the perspective of employee.
Assessing similarity: on homology, characters and the need for a semantic approach to non‐evolutionary comparative homology
Authors: Vogt Lars
Published: November 2016

The problem of homology has been a consistent source of controversy at the heart of systematic biology, as has the step of morphological character analysis in phylogenetics. Based on a clear epistemic framework and a characterization of “characters” as diagnostic evidence units for the recognition of not directly identifiable entities, I discuss the ontological definition and empirical recognition criteria of phylogenetic, developmental and comparative homology, and how these three accounts of homology each contribute to an understanding of the overall phenomenon of homology. I argue that phylogenetic homologies are individuals or historical kinds that require comparative homology for identification. Developmental homologies are natural kinds that ultimately rest on phylogenetic homologies and also require comparative homology for identification. Comparative homologies on the other hand are anatomical structural kinds that are directly identifiable. I discuss pre‐Darwinian comparative homology concepts and their problem of invoking non‐material forces and involving the a priori assumption of a stable positional reference system. Based on Young's concept of comparative homology, I suggest a procedure for recognizing comparative homologues that lacks these problems and that utilizes a semantic framework. This formal conceptual framework provides the much needed semantic transparency and computer‐parsability for documenting, communicating and analysing similarity propositions. It provides an essential methodological framework for generalizing over individual organisms and identifying and demarcating anatomical structural kinds, and it provides the missing link to the logical chain of identifying phylogenetic homology. The approach substantially increases the analytical accessibility of comparative research and thus represents an important contribution to the theoretical and methodological foundation of morphology and comparative biology.
4β‐Hydroxycholesterol Level in Patients With Rheumatoid Arthritis Before vs. After Initiation of bDMARDs and Correlation With Inflammatory State
Authors: Wollmann BM , Syversen SW , Lie E , Gjestad C , Mehus LL , Olsen IC , Molden E
Published: November 2016

Systemic inflammation has been linked to suppressed CYP3A(4) activity. We determined 4β‐hydroxycholesterol (4βOHC), an endogenous CYP3A4 metabolite, in patients with rheumatoid arthritis (RA) before and after treatment with biological disease‐modifying antirheumatic drugs (bDMARDs). The 4βOHC was compared in 41 patients before and 2–5 months after initiating TNFα inhibitors (n = 31), IL‐6 inhibitors (n = 5), or B‐cell inhibitors (n = 5). Correlations between 4βOHC and inflammatory markers (C‐reactive protein (CRP) and erythrocyte sedimentation rate (ESR)) were also tested before and after bDMARDs. 4βOHC did not differ following bDMARD treatment (P = 0.6), nor in patients who started with IL‐6 inhibitors (median 51.6 vs. 50.6 nmol/L). The 4βOHC and CRP/ESR did not correlate before treatment (P > 0.5), but correlated significantly after bDMARDs (CRP = Spearman r ‐0.40; P < 0.01; ESR = r ‐0.34; P = 0.028) suggesting that mainly non‐CYP3A4‐suppressive cytokines were reduced during treatment. Thus, this study does not support a generally regained CYP3A4 phenotype in patients with RA following initiation of bDMARDs.
A comparative study in descriptions of coupled kinematic hardening rules and ratcheting assessment over asymmetric stress cycles
Authors: Varvani‐Farahani A
Published: November 2016

The present study evaluates coupled kinematic hardening rules at which the calculation of plastic moduli is coupled with these models through the consistency condition of yield surfaces. The frameworks of the Ohno–Wang (O–W), McDowell, Jiang–Sehitoglu (J–S), Chen–Jiao–Kim (C–J–K) and Ahmadzadeh–Varvani (A–V) hardening rules and their incorporated dynamic recovery terms/coefficients were discussed for steel samples undergoing asymmetric stress cycles. Different hardening rules offered distinct procedures to determine terms/coefficients and to generalize hardening rule descriptions applicable for different materials and loading spectra. The progressive evolution of backstress over plastic deformation was attributed to the interaction of dislocations controlled by the dynamic recovery of the models. The predicted ratcheting curves through the C–J–K and A–V hardening rules closely agreed with ratcheting data of 1045 and 304 steel samples tested at different loading paths. The O–W, J–S and McDowell hardening rules showed some overprediction in ratcheting as compared with experimental data.
Prognostic Implications of Defibrillation Threshold Testing in Patients With Hypertrophic Cardiomyopathy
Authors: FRANCIA PIETRO , ADDUCI CARMEN , SEMPRINI LORENZO , PALANO FRANCESCA , SANTINI DARIA , MUSUMECI BEATRICE , SANTOLAMAZZA CATERINA , VOLPE MASSIMO , AUTORE CAMILLO
Published: November 2016

DFT in ICD Patients With HCM

Introduction

In hypertrophic cardiomyopathy (HCM) patients the need for defibrillation threshold (DFT) testing at the time of ICD implantation is debated. Moreover, its prognostic implications have never been explored. In a cohort of HCM patients we sought to (a) investigate factors prompting DFT testing, (b) evaluate ICD efficacy by testing DFT, (c) compare DFT in patients with and without massive LVH, and (d) assess whether DFT testing predicts shock efficacy for spontaneous VT/VF.

Methods and Results

We retrospectively analyzed a cohort of HCM patients implanted with an ICD. DFT was tested at the discretion of the implanting physician with a 10 J safety margin. During follow‐up, ICD interventions were evaluated. The study population included 66 patients. DFT was determined in 25 (38%) patients. Age (HR: 0.95; 95%CI: 0.92–0.98; P = 0.004) and massive LVH (HR: 6.0; 95%CI: 2.03–18.8; P = 0.001) affected the decision to test DFT. DFT was at least 10 J less than maximal ICD output in 25/25. Safety margin was similar among patients with and without massive LVH (15 ± 3 J vs. 14 ± 2 J; P = 0.42). During follow‐up (median 53 months) 15 shocks were delivered for 12 VT/VF in 7 patients. One VF ended spontaneously after a failed shock. Of 4 unsuccessful shocks, 2 occurred in 1 patient with DFT testing and 2 were delivered in 2 patients without. All unsuccessful shocks were ≤35 J.

Conclusion

Young age and massive LVH prompt DFT testing. Contemporary ICDs are safe and effective in HCM patients independently from the magnitude of LVH. DFT testing does not predict shock efficacy for spontaneous VT/VF.
The To and Fro of Documents: Vying for Recognition in Enawene‐nawe Dealings with the Brazilian State
Authors: Nahum‐Claudel Chloe
Published: November 2016

O artigo considera como uma população Ameríndia, os Enawene‐nawe, dispõem os seus documentos ao lidar com o Estado brasileiro e com empresas construtoras de barragens hidroelétricas. O foco reside na maneira como o uso dos documentos se relaciona com a ideologia linguística existente e com as práticas políticas—consideradas conjuntamente como um estilo de “diplomacia externa”. A troca de documentos é um aspecto de uma dinâmica diplomática mais ampla, de abertura e fechamento, por meio da qual os Enawene demandam reconhecimento dos estrangeiros poderosos. O argumento é o de que a comunicação por meio de documentos é eficaz e desejável para os Enawene por que forjam um canal de reciprocidade delimitado num grande oceano de desentendimento, na medida em que os documentos constituem um mediador ou uma fronteira entre eles mesmos e os de fora. Por isso os Enawene instrumentalizam essa característica do formalismo burocrático que é, normalmente, concebida como a sua limitação: a separação de modos de expressão cotidianos e de entendimentos compartilhados.
Diagnostic contribution of cytological specimens obtained from biopsies during gastrointestinal endoscopy in dogs and cats
Authors: Ruiz G. , Verrot L. , Laloy E. , Benchekroun G.
Published: November 2016

Objectives

The aims of this study were to compare cytological samples obtained from endoscopic biopsies using “imprint” and “squash” techniques, and to evaluate the potential value of cytology compared to histology in reaching the diagnosis.

Materials and Methods

Eighteen dogs and five cats undergoing endoscopy for chronic gastrointestinal signs were prospectively included. Imprint and squash samples were obtained from one biopsy and then analysed. Comparison between cytology and histology was performed using Cohen's j coefficient.

Results

Appropriate samples for cytological evaluation were more often obtained with the squash technique (96% of the casesversus68% with the imprint technique). The diagnoses obtained with cytological samples and by histology, considered as the gold standard, were compared. The same diagnosis was obtained with the squash technique in 65% of the cases. Furthermore, cytology was considered complementary to histology for gastric spiral organisms and mast cells identification.

Clinical Significance

These results suggest that squash cytology obtained from endoscopic biopsies of the gastrointestinal tract can provide relevant and additional information to histology in dogs and cats.
25 Years of Transparency Research: Evidence and Future Directions
Authors: Cucciniello Maria , Porumbescu Gregory A. , Grimmelikhuijsen Stephan
Published: November 2016

This article synthesizes the cross‐disciplinary literature on government transparency. It systematically reviews research addressing the topic of government transparency published between 1990 and 2015. The review uses 187 studies to address three questions: (1) What forms of transparency has the literature identified? (2) What outcomes does the literature attribute to transparency? and (3) How successful is transparency in achieving those goals? In addressing these questions, the authors review six interrelated types of transparency and nine governance‐ and citizen‐related outcomes of transparency. Based on the findings of the analysis, the authors outline an agenda for future research on government transparency and its effects that calls for more systematically investigating the ways in which contextual conditions shape transparency outcomes, replicating studies with varying methodologies, investigating transparency in neglected countries, and paying greater attention to understudied claims of transparency such as improved decision making and management.
Toxic effects of nitrite on freshwater organisms: a review
Authors: Kocour Kroupová Hana , Valentová Olga , Svobodová Zdeňka , Šauer Pavel , Máchová Jana
Published: November 2016

High nitrite concentrations may occur mainly in recirculating aquaculture systems, but can also be found under certain conditions in natural waters. Among studied freshwater organisms, molluscs and worms followed by fish are the most resistant to nitrite. On the other hand, crustaceans and aquatic insects followed by amphibians are the most sensitive. Wide interspecific differences in nitrite susceptibility can be found within freshwater insects, crustaceans and amphibians. Chloride concentration in water is supposed to be the most important factor influencing nitrite toxicity. Generally, a positive chloride effect on nitrite toxicity reduction can be expected in all aquatic animals (or their early stages) employing gills for breathing and ion exchange. This phenomenon has already been observed in an amphipod (Eulimnogammarus toletanus, Pinkster & Stock), a planarian (Polycelis felina, Dalyell), two species of crayfish, several fish species and in amphibians in early development stages. A relatively huge amount of data on nitrite effects is available for fish, but other freshwater organisms were less frequently studied. Information on chronic effect of nitrite is nearly completely missing.
Vagueness and Goodness Simpliciter
Authors: Andersson Henrik
Published: November 2016

Recently a lot has been written on the topic of value incomparability. While there is disagreement on how we are to understand incomparability, most seem to accept Ruth Chang's claim that all comparisons must proceed in some specific respect. Call this the Requirement for Specification. Interestingly, even though most seem to accept this requirement, next to nothing has been written on it. In this paper I focus on the requirement and discuss two different but related topics. First, an important observation is made: as it turns out, the requirement plays an important explanatory role for the thesis that incomparability is to be understood in terms of vagueness. Second, I consider what is entailed by the Requirement for Specification. There is a general worry that the requirement entails that there is no such thing as goodness simpliciter. The line of thought is that if we always must specify in which way something is e.g., better than something else, then perhaps things cannot be better simpliciter. And if there is no such thing as betterness‐simpliciter, then can there be such a thing as goodness simpliciter? Finally, I consider how an answer to this question affects the view that incomparability is vagueness.
Causal and Moral Indeterminacy
Authors: Bernstein Sara
Published: November 2016

This paper argues that several sorts of metaphysical and semantic indeterminacy afflict the causal relation. If, as it is plausible to hold, there is a relationship between causation and moral responsibility, then indeterminacy in the causal relation results in indeterminacy of moral responsibility more generally.
Prior antimicrobial use as a risk factor for resistance in selected Staphylococcus pseudintermedius isolates from the skin and ears of dogs
Authors: Zur Gila , Gurevich Bella , Elad Daniel
Published: November 2016

Background

Antimicrobial resistance within bacteria continues to present therapeutic challenges. One presumed risk factor for increased rates of resistance is prior exposure to antimicrobial drugs.

Objectives

To examine the impact of time since most recent exposure, the number of prior antimicrobial exposures and duration of use on antimicrobial resistance rates in Staphylococcus pseudintermedius isolates.

Methods

Inclusion of a case in the study required laboratory isolation of S. pseudintermedius from a clinical specimen. Antibiograms and information regarding prior antimicrobial exposures were extracted from the medical records of dogs diagnosed with pyoderma or otitis externa.

Results

Meticillin resistance (MR) was identified in 48.1% of isolates. Recent use of beta‐lactam antimicrobials was associated with increased odds of resistance to meticillin (P < 0.001) and fluoroquinolones (P < 0.001). Antimicrobial therapy within 1 month prior to sampling was also associated with MR (60.7%; P = 0.009) and multidrug resistance (61.9%; P = 0.029). The number of prior exposures to beta‐lactams or fluoroquinolones were associated with resistance to these same classes (P = 0.001 and 0.02, respectively) and to other antimicrobial classes (P = 0.016 for resistance to fluoroquinolones following treatment with beta‐lactams and P = 0.015 for MR following treatment with fluoroquinolones). Longer treatment duration with beta‐lactam drugs was associated with higher proportion of MR (P = 0.004).

Conclusions and clinical importance

Treatment based upon culture and susceptibility testing is highly recommended for dogs that have received multiple antimicrobial drug exposures or that were treated within the preceding month. This may be especially important when the prior therapeutic regimen included a drug from the beta‐lactam or fluoroquinolone classes.
Investigation of the Inertial Focusing Behavior in Curved Microfluidic Channels for Different Aspect Ratio
Authors: Setayesh Hagh Alireza , Dinler Ali
Published: November 2016

Inertial focusing has attracted a significant attention in microfluidics applications in recent years. Inertial focusing occurs only under specific flow conditions at which particles migrate across streamlines to a specific number of equilibrium positions. This behavior is mostly not sensitive to the particle size in straight channels. However, curved channels can allow sized based particle separation. In this study, curved channels with various aspect ratios have been investigated by numerical simulations. Consideration of flow regimes reveals that some conditions establish a high-quality single-particle focusing situation which is characterized by the alignment of particles within a narrow band. The outcomes of our numerical model contribute to the understanding of limitation of particle focusing and particle separation in curved microchannels.
Oil-Water Flow Visualization and Flow Regimes in a 3.7 mm Mini-Channel
Authors: Bultongez Kevin K. , Derby Melanie M.
Published: November 2016

This study investigates adiabatic oil and water flow patterns in a 3.7-mm-inner-diameter borosilicate glass tube. A closed-loop flow apparatus was constructed and pressure drop was verified using single-phase liquid water. Minor losses were shown to be negligible, and 98% of the pressure drop occurred in the glass tube. Oil-water tests were conducted over a range of oil superficial velocities (0.27 < jo < 3.3 m/s) and water superficial velocities (0.07 < jw < 4.96 m/s). Annular, intermittent, and dispersed flow regimes were observed and shown. For nearly all cases, an annular water ring formed along the perimeter of the glass tube. Two-phase pressure drops are reported.
Porous Transport Layer Related Mass Transport Losses in Polymer Electrolyte Membrane Electrolysis: A Review
Authors: Lee Chung Hyuk , Banerjee Rupak , Arbabi Faraz , Hinebaugh James , Bazylak Aimy
Published: November 2016

The unintended accumulation of oxygen gas in polymer electrolyte membrane (PEM) electrolyzers has been recently identified as one of the main hurdles to achieving high cell efficiencies. Oxygen is a by-product of the electrochemical reaction used to produce hydrogen, and this oxygen must be removed in order to reduce mass transport losses. The porous transport layer (PTL) is a key component of the PEM electrolyzer which facilitates mass transport and electrical conductance. However, oxygen bubble accumulation potentially dominates the total mass transport losses during operation. Many experimental and computational studies have been performed in an attempt to understand the relationship between the morphology of the PTL and the voltage loss of the electrolyzer, but this relationship has yet to be fully defined. In this work, efforts towards identifying and understanding mass transport losses are discussed. PTL structural parameters that were shown to affect performance, such as bulk porosity, particle size, pore size, thickness, and permeability are reviewed. Visualization techniques that have been employed to investigate the behavior of oxygen bubbles are also discussed. This work presents a summary of the studies which have been performed to investigate the key parameters of the PTL that should be tailored for improved PEM electrolyzer performance.
Enhanced Flow Boiling Heat Transfer Using Radial Microchannels
Authors: Recinella Alyssa , Kalani Ankit , Kandlikar Satish G.
Published: November 2016

Flow boiling has the ability to remove high heat fluxes while maintaining a low wall superheat. Various researchers have developed enhanced microchannel geometries to improve the heat transfer performance of the system. Recently, a number of new studies have used the increasing flow cross-sectional area concept to overcome flow instabilities and record high CHF. In this work, a new geometry is experimentally investigated utilizing a radial cross-section, which provides the increasing fluid flow cross-sectional area in the flow direction. The flow boiling performance is studied using radial microchannels and water as the working fluid. Four different flow rates ranging from 120–400 mL/min are studied for this new geometry. Heat transfer performance (boiling curve and heat transfer coefficient) and pressure drop characteristics are discussed for all flow rates. Furthermore, the work is supported by high speed visualization of the bubble dynamics. The boiling performance obtained is compared to the existing data in the literature.
Metallic Nanoemulsion for Microchannel Heat-Sink
Authors: Hayashi Yoshikazu , Yip Gordon , Kim Yoon Jo , Kim Jong-Hoon
Published: November 2016

Galinstan is a eutectic alloy of gallium, indium, and tin, of which thermal conductivity is ∼27 times higher than that of water, while the dynamic viscosity is only twice. Thus, heat transfer coefficient can be remarkably enhanced with a small penalty of pumping power. However, the direct use of galinstan can suffer from practical issues such as oxidation and low specific heat. Therefore, galinstan is mixed with a coolant as an additive to form a colloidal fluid; i.e., dispersion of nanoscale galinstan droplets in a coolant to enhance the thermal conductivity. It is expected that this “metallic nanoemulsion” can contribute to substantial improvement in heat transfer capability. Also, the common issues with colloidal fluids such as rapid sedimentation, erosion, and clogging, can be minimized by the “fluidity” of the liquid metal.

It was shown that ultrasonic emulsification can yield few hundreds scale nanodroplets. However, the long exposure of galinstan to oxygen in water inevitably results in severe oxidation of the droplets. Theoretical analysis was also conducted to examine the feasibility of the metallic nanoemulsion as a microchannel heat-sink working fluid. Effective medium theory was used to evaluate the thermal conductivity of the mixture. The viscosity change was also predicted considering both the viscosity of dispersed phase and interaction between the droplets. Under one-dimensional laminar flow assumption, mass, momentum, and energy conservation equations were analytically solved. The effect of high thermal conductivity of galinstan was evident; the convection heat transfer capability was greatly enhanced, while the viscosity increase due to the nanoscale blending and the low specific heat of galinstan counteracts and reduce the flow rate and thus increase the caloric thermal resistance.
Effect of Open Micro-Channels on External Condensation Heat Transfer
Authors: Hulet Brandon , Martinez Andres , Derby Melanie , Betz Amy Rachel
Published: November 2016

This research experimentally investigates the heat transfer performance of open-micro channels under filmwise condensation conditions. Filmwise condensation is an important factor in the design of steam condensers used in thermoelectric power generation, desalination, and other industrial applications. Filmwise condensation averages five times lower heat transfer coefficients than those present in dropwise condensation, and filmwise condensation is the dominant condensation regime in the steam condensers due to a lack of a durable dropwise condensation surface. Film thickness is also of concern because it is directly proportional to the condenser’s overall thermal resistance. This research focuses on optimizing the channel size to inhibit the creation of a water film and/or to reduce its overall thickness in order to maximize the heat transfer coefficient of the surface. Condensation heat transfer was measured in three square channels and a plane surface as a control. The sizes of the square fins were 0.25 mm; 0.5 mm; and 1 mm, and tests were done at a constant pressure of 6.2 kPa. At lower heat fluxes, the 0.25mm fins perform better, whereas at larger heat fluxes a smooth surface offers better performance. At lower heat fluxes, droplets are swept away by gravity before the channels are flooded. Whereas, at higher heat fluxes, the channels are flooded increasing the total film thickness, thereby reducing the heat transfer coefficient.
Experimental Characterization and Modeling of Capillary-Pumped Thin-Film Evaporation From Micropillar Wicks
Authors: Adera Solomon , Antao Dion , Raj Rishi , Wang Evelyn N.
Published: November 2016

Generation of concentrated heat load in confined spaces in integrated circuits and advanced microprocessors has presented a thermal management challenge for the semiconductor industry. Compared to state-of-the-art single phase cooling strategies, phase-change based approaches are promising for cooling the next generation microelectronic devices. In particular, thin-film evaporation from engineered surfaces has received significant attention in the last few decades as a potential candidate since it enables passive transport of the working fluid via capillarity in addition to increasing the evaporation area via extending the liquid meniscus and three-phase contact line. Thin-film evaporation, however, is coupled with nucleate boiling making experimental characterization as well as modeling of the fluidic and thermal transport a challenging task for thermal engineers. Furthermore, quantifying the relative contributions of nucleate boiling and thin-film evaporation from the experimentally reported heat fluxes has been difficult. Unlike previous studies, our work experimentally characterizes thin-film evaporation in the absence of nucleate boiling from arrays of silicon micropillars. In particular, we characterize the capillary-limit where the microstructured surface dries out due to liquid starvation when the capillary pressure that is generated due to the meniscus shape cannot overcome the viscous losses within the micropillar wick. We modeled the fluidic and thermal transport of the evaporating meniscus by solving the coupled heat and mass transfer equations. Compared to experiments, our model predicts the dryout heat flux with ±20% accuracy. The insights gained from this study provide a suitable platform to design and optimize micropillar wicks for phase-change based thermal management devices such as heat pipes and vapor chambers.
Multitechnique characterization of oligo(ethylene glycol) functionalized gold nanoparticles
Authors: Rafati Ali , Shard Alexander G. , Castner David G.
Published: November 2016

Gold nanoparticles (AuNPs) with average diameters of ∼14 and ∼40 nm, as well as flat gold coated silicon wafers, were functionalized with oligo ethylene glycol (OEG) terminated 1-undecanethiol (HS-CH2)11 self-assembled monolayers (SAMs). Both hydroxyl [(OEG)4OH] and methoxy [(OEG)4OMe] terminated SAMs were prepared. The AuNPs were characterized with transmission electron microscopy (TEM), time of flight secondary ion mass spectrometry (ToF-SIMS), x-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier infrared spectroscopy (ATR-FTIR), and low-energy ion scattering (LEIS). These studies provided quantitative information about the OEG functionalized AuNPs. TEM showed the 14 nm AuNPs were more spherical and had a narrower size distribution than the 40 nm AuNPs. ToF-SIMS clearly differentiated between the two OEG SAMs based on the C3H7O+ peak attributed to the methoxy group in the OMe terminated SAMs as well as the different masses of the [Au + M]− ion (M = mass of the thiol molecule) from each type of SAM. Overlayer/substrate ratios quantitatively determined with XPS show a greater proportion of OEG units at the surface of 40 nm AuNPs compared to the 14 nm AuNPs. ATR-FTIR suggested the C11 backbone of the two SAMs on both AuNPs are similar and crystalline, but the OEG head groups are more crystalline on the 40 nm AuNPs compared to the 14 nm AuNPs. This indicated a better ordered SAM present at the surface of the larger, more irregular particles due to greater ordering of the OEG groups. This was consistent with the XPS and LEIS results, which showed a 30% thicker SAM was formed on the 40 nm AuNPs compared to the 14 nm AuNPs. The OH or OMe functionality did not have a significant effect on the ordering and thickness of the OEG SAMs.