bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal structures ofLeishmania mexicanaarginase complexed with α,α-disubstituted boronic amino-acid inhibitors
Authors: Hai Yang , Christianson David W.
Published: March 2016

Leishmaniaarginase is a potential drug target for the treatment of leishmaniasis because this binuclear manganese metalloenzyme initiatesde novopolyamine biosynthesis by catalyzing the hydrolysis of L-arginine to generate L-ornithine and urea. The product L-ornithine subsequently undergoes decarboxylation to yield putrescine, which in turn is utilized for spermidine biosynthesis. Polyamines such as spermidine are essential for the growth and survival of the parasite, so inhibition of enzymes in the polyamine-biosynthetic pathway comprises an effective strategy for treating parasitic infections. To this end, two X-ray crystal structures ofL. mexicanaarginase complexed with α,α-disubstituted boronic amino-acid inhibitors based on the molecular scaffold of 2-(S)-amino-6-boronohexanoic acid are now reported. Structural comparisons with human and parasitic arginase complexes reveal interesting differences in the binding modes of the additional α-substituents,i.e.the D side chains, of these inhibitors. Subtle differences in the three-dimensional contours of the outer active-site rims among arginases from different species lead to different conformations of the D side chains and thus different inhibitor-affinity trends. The structures suggest that it is possible to maintain affinity while fine-tuning intermolecular interactions of the D side chain of α,α-disubstituted boronic amino-acid inhibitors in the search for isozyme-specific and species-specific arginase inhibitors.
Exploring the role of leadership style on the service quality-customer satisfaction link
Authors: Pantouvakis Angelos , Patsiouras Christos
Published: March 2016

Purpose

– The purpose of this paper is to explore the influence of the leadership style on the service quality–customer satisfaction link.

Design/methodology/approach

– A special survey instrument was developed and tested with the use of exploratory factor and regression analyses.

Findings

– Data from 118 small enterprises were collected through personal interviews, and results supported that the level of leadership style moderates the relationship between service quality and customer satisfaction despite what is commonly believed that leadership actually is a prerequisite of service quality.

Practical/implications

– Based on the fact that there is no literature connecting quality and satisfaction with leadership style, practitioners may be interested in finding out that executives’ behavior can influence the service provided to customers.

Originality/value

– Leadership style is a concept which has been associated with many variables such as service quality, performance and job satisfaction. In the marketing literature, it has been widely accepted that service quality is positively related to customer satisfaction. This work is the first trying to examine the effect of leadership style on service quality–customer satisfaction linkage under conditions of environmental uncertainty and instability.
Modularity matters: a critical review and synthesis of service modularity
Authors: Iman Nofie
Published: March 2016

Purpose

– The literature on modularity is extensive, but most research has been concerned with the manufacturing sector and much less with the service sector. The purpose of this paper is to investigate the existing research, to provide a critique of the empirical literature on service modularity and to discuss future research opportunities.

Design/methodology/approach

– To perform this analysis of service modularity, a list of top-tier journals in the field of business management and organisation was compiled. From there, each and every article was identified, examined, coded and classified into high-level themes. These were then reviewed, analysed and interpreted.

Findings

– This paper argues that the application of modularity in services will likely be influenced by certain characteristics that distinguish services from products. Second, modularity, from the service perspective, has been closely connected to productisation of services, and the discussion of modularity related to services has been greatly influenced by the earlier discussion on product modularity. This paper concludes that modularity in the service development context is still seeking its theoretical “identity” and requires further theoretical and empirical work on service design modularity conceptualisation, methods and measures.

Originality/value

– This paper has reviewed several significant fields with which research on service modularity has been concerned. It captures and presents the core notion of service modularity in a critical way that might spur further research in the field.
Customer orientation in a Swedish county council
Authors: Karlsson Margareta , Garvare Rickard , Zingmark Karin , Nordström Birgitta
Published: March 2016

Purpose

– The use of the customer concept and ways of interacting with customers in support functions are relatively new areas of interest for public organizations. The purpose of this study is to describe the development toward a stronger customer orientation in a support function in a Swedish county council from a management team perspective.

Design/methodology/approach

– A revision of plans and annual reports and individual interviews with the members of a management team was done. The interviews were examined using qualitative content analysis.

Findings

– The results are presented in one overarching theme, the double-edged customer concept, and three themes, meeting the customer’s needs, being the customer’s specialist and developing in collaboration with the customer. The development of a customer orientation is illustrated as a spiral involving the concepts of understanding, wanting and acting.

Originality/value

– The paper contributes to a new understanding of how customer orientation develops in the context of public organizations’ support functions.
On the Influence of Array Size and Jet Spacing on Jet Interactions and Confluence in Round Jet Arrays
Authors: Svensson Klas , Rohdin Patrik , Moshfegh Bahram
Published: March 2016

This work uses computational models to study the effects of confluence and jet-to-jet interactions for inline matrices of confluent round jets. In total, 12 different confluent jet arrangements, having various jet array sizes and dimensionless jet spacing, S/d0, have been investigated. The array size varies from 6 × 6 to 10 × 10 jets, while S/d0 varies between 1.75≤S/d0≤4.0. The Reynolds number, based on the nozzle exit diameter, is between 2200 and 6600. The results show that both jet spacing and jet array size largely influence the jet-to-jet interactions and flow field development in confluent jet arrays. The jet interactions in the investigated setups result in regions of negative static pressure between jets, jet deformation, high spanwise velocity, and jet displacement. Generally, smaller jet spacing and larger array size result in stronger influence of jet interactions. After the jets have combined, the confluent jets form a zone with constant maximum streamwise velocity and decay of turbulence intensity, called a confluent core zone (CCZ). During the CCZ, the combined jet will have asymmetric spreading rates leading to axis-switching. The entrainment rate of the CCZ is constant, but the volumetric flow rate of the combined jet is substantially affected by the degree of entrainment before the jets have combined.
Gas-Assisted Droplet Impact on a Solid Surface
Authors: Diaz Andres J. , Ortega Alfonso
Published: March 2016

An experimental, numerical, and theoretical investigation of the behavior of a gas-assisted liquid droplet impacting on a solid surface is presented with the aim of determining the effects of a carrier gas on the droplet deformation dynamics. Experimentally, droplets were generated within a circular air jet for gas Reynolds numbers Reg = 0–2547. High-speed photography was used to capture the droplet deformation process, whereas the numerical analysis was conducted using the volume of fluid (VOF) model. The numerical and theoretical predictions showed that the contribution of a carrier gas to the droplet spreading becomes significant only at high Weo and when the work done by pressure forces is greater than 10% of the kinetic energy. Theoretical predictions of the maximum spreading diameter agree reasonably well with the experimental and numerical observations.
Design of a Soft Robotic Glove for Hand Rehabilitation of Stroke Patients With Clenched Fist Deformity Using Inflatable Plastic Actuators
Authors: Yap Hong Kai , Lim Jeong Hoon , Goh James Cho Hong , Yeow Chen-Hua
Published: March 2016

In this paper, we present a soft robotic glove designed to augment hand rehabilitation for stroke patients with clenched fist deformity. The robotic glove provides active finger extension for hand rehabilitative training, through its embedded inflatable actuators that are fabricated by heat bonding of flexible plastic sheets. Upon pressurization, the actuators inflate, stiffen, and extend the fingers. The actuators were embedded in the finger pockets of a glove. In this work, the device was evaluated in terms of its extension torque generated on the metacarpophalangeal (MCP) joint of a dummy finger model and a healthy subject. A stroke patient with finger spasticity was recruited to demonstrate the feasibility of the device to assist in finger extension. Preliminary results showed that the device was able to generate significant extension torques to provide assistance in finger extension for both healthy and stroke participants.
Stability Analysis of Milling Processes With Periodic Spindle Speed Variation Via the Variable-Step Numerical Integration Method
Authors: Niu Jinbo , Ding Ye , Zhu LiMin , Ding Han
Published: March 2016

This paper proposes a general method for the stability analysis and parameter optimization of milling processes with periodic spindle speed variation (SSV). With the aid of Fourier series, the time-variant spindle speeds of different periodic modulation schemes are unified into one framework. Then the time-varying delay is derived implicitly and calculated efficiently using an accurate ordinary differential equation (ODE) based algorithm. After incorporating the unified spindle speed and time delay into the dynamic model, a Floquet theory based variable-step numerical integration method (VNIM) is presented for the stability analysis of variable spindle speed milling processes. By comparison with other methods, such as the semi-discretization method and the constant-step numerical integration method, the proposed method has the advantages of high computational accuracy and efficiency. Finally, different spindle speed modulation schemes are compared and the modulation parameters are optimized with the aid of three-dimensional stability charts obtained using the proposed VNIM.
Pulsed laser deposition of highly oriented stoichiometric thin films of topological insulator Sb2Te3
Authors: Saha Biswajit , Chaturvedi Pragati , Yadav Anil K. , Saha Dipankar , Ganguly Swaroop
Published: March 2016

Topological insulators (TI) are currently the focus of strong interest because of their extraordinary physical properties related to Dirac surface states. The ability to grow high quality thin films of TI materials still remains the key issue in exploring their fundamental physical properties and utilizing them for future technological application. One of the major concerns being the presence of unintentional bulk carriers due to nonstoichiometric growth of TI thin films by most of the state-of-the-art thin film deposition techniques. In this paper, the authors report a potential route to grow highly oriented stoichiometric TI thin films by pulsed laser deposition (PLD). Preservation of chemical composition due to stoichiometric transfer of ablated target material on substrate provides a potential route for chemical doping of TI films. The authors have studied the effect of various growth parameters and optimized them to achieve highly oriented antimony telluride (Sb2Te3) films by PLD. They show that the laser energy density (Ed) and substrate temperature play a key role in tuning surface morphology, crystallinity, and composition of PLD grown Sb2Te3 films. The average grain size of the Sb2Te3 films shows a remarkable increase in the substrate temperature. X-ray diffraction confirms the growth of highly oriented Sb2Te3 films at the substrate temperature of around 300 °C. This observation is supported by the transmission electron microscopy results. All the films exhibit the characteristic in-plane (Eg2) and out-of-plane (A1g2) Raman vibrational modes at ∼114 and 168 cm−1, respectively. The energy dispersive x-ray spectroscopy measurement confirms the desired stoichiometry of the grown films.
Uniform deposition of size-selected clusters using Lissajous scanning
Authors: Beniya Atsushi , Hirata Hirohito , Watanabe Yoshihide
Published: March 2016

Size-selected clusters can be deposited on the surface using size-selected cluster ion beams. However, because of the cross-sectional intensity distribution of the ion beam, it is difficult to define the coverage of the deposited clusters. The aggregation probability of the cluster depends on coverage, whereas cluster size on the surface depends on the position, despite the size-selected clusters are deposited. It is crucial, therefore, to deposit clusters uniformly on the surface. In this study, size-selected clusters were deposited uniformly on surfaces by scanning the cluster ions in the form of Lissajous pattern. Two sets of deflector electrodes set in orthogonal directions were placed in front of the sample surface. Triangular waves were applied to the electrodes with an irrational frequency ratio to ensure that the ion trajectory filled the sample surface. The advantages of this method are simplicity and low cost of setup compared with raster scanning method. The authors further investigated CO adsorption on size-selected Ptn (n = 7, 15, 20) clusters uniformly deposited on the Al2O3/NiAl(110) surface and demonstrated the importance of uniform deposition.
Production of a biofunctional titanium surface using plasma electrolytic oxidation and glow-discharge plasma for biomedical applications
Authors: Beline Thamara , Marques Isabella da Silva Vieira , Matos Adaias O. , Ogawa Erika S. , Ricomini-Filho Antônio P. , Rangel Elidiane C. , da Cruz Nilson Cristino , Sukotjo Cortino , Mathew Mathew T. , Landers Richard , Consani Rafael L. X. , Mesquita Marcelo Ferraz , Barão Valentim Adelino Ricardo
Published: March 2016

In this study, the authors tested the hypotheses that plasma electrolytic oxidation (PEO) and glow-discharge plasma (GDP) would improve the electrochemical, physical, chemical, and mechanical properties of commercially pure titanium (cpTi), and that blood protein adsorption on plasma-treated surfaces would increase. Machined and sandblasted surfaces were used as controls. Standard electrochemical tests were conducted in artificial saliva (pHs of 3.0, 6.5, and 9.0) and simulated body fluid. Surfaces were characterized by scanning electron microscopy, energy-dispersive spectroscopy, x-ray photoelectron spectroscopy, atomic force microscopy, x-ray diffraction, profilometry, Vickers microhardness, and surface energy. For biological assay, the adsorption of blood serum proteins (i.e., albumin, fibrinogen, and fibronectin) was tested. Higher values of polarization resistance and lower values of capacitance were noted for the PEO and GDP groups (p < 0.05). Acidic artificial saliva reduced the corrosion resistance of cpTi (p < 0.05). PEO and GDP treatments improved the surface properties by enrichment of the surface chemistry with bioactive elements and increased surface energy. PEO produced a porous oxide layer (5-μm thickness), while GDP created a very thin oxide layer (0.76-μm thickness). For the PEO group, the authors noted rutile and anatase crystalline structures that may be responsible for the corrosion barrier improvement and increased microhardness values. Plasma treatments were able to enhance the surface properties and electrochemical stability of titanium, while increasing protein adsorption levels.
Chronic skin inflammation leads to bone loss by IL-17–mediated inhibition of Wnt signaling in osteoblasts
Authors: Uluçkan Özge , Jimenez Maria , Karbach Susanne , Jeschke Anke , Graña Osvaldo , Keller Johannes , Busse Björn , Croxford Andrew L. , Finzel Stephanie , Koenders Marije , van den Berg Wim , Schinke Thorsten , Amling Michael , Waisman Ari , Schett Georg , Wagner Erwin F.
Published: March 2016

Skin inflammation inhibits bone formation through IL-17A.
The live attenuated dengue vaccine TV003 elicits complete protection against dengue in a human challenge model
Authors: Kirkpatrick Beth D. , Whitehead Stephen S. , Pierce Kristen K. , Tibery Cecilia M. , Grier Palmtama L. , Hynes Noreen A. , Larsson Catherine J. , Sabundayo Beulah P. , Talaat Kawsar R. , Janiak Anna , Carmolli Marya P. , Luke Catherine J. , Diehl Sean A. , Durbin Anna P.
Published: March 2016

A controlled dengue human challenge model may determine whether to evaluate candidate dengue vaccines in large efficacy trials.
An old inhibitor with new tricks
Authors: Beswick Ellen J.
Published: March 2016

Combination therapy offers new ways to enhance tumor immunotherapy.
Molecular and Structural Characterization of a Novel Escherichia coli Interleukin Receptor Mimic Protein
Authors: Moriel Danilo G. , Heras Begoña , Paxman Jason J. , Lo Alvin W. , Tan Lendl , Sullivan Matthew J. , Dando Samantha J. , Beatson Scott A. , Ulett Glen C. , Schembri Mark A.
Published: March 2016

Urinary tract infection (UTI) is a disease of extremely high incidence in both community and nosocomial settings. UTIs cause significant morbidity and mortality, with approximately 150 million cases globally per year. Uropathogenic
Escherichia coli
(UPEC) is the primary cause of UTI and is generally treated empirically. However, the rapidly increasing incidence of UTIs caused by multidrug-resistant UPEC strains has led to limited available treatment options and highlights the urgent need to develop alternative treatment and prevention strategies. In this study, we performed a comprehensive analysis to define the regulation, structure, function, and immunogenicity of recently identified UPEC vaccine candidate C1275 (here referred to as IrmA). We showed that the
irmA
gene is highly prevalent in UPEC, is cotranscribed with the biofilm-associated antigen 43 gene, and is regulated by the global oxidative stress response OxyR protein. Localization studies identified IrmA in the UPEC culture supernatant. We determined the structure of IrmA and showed that it adopts a unique domain-swapped dimer architecture. The dimeric structure of IrmA displays similarity to those of human cytokine receptors, including the interleukin-2 receptor (IL-2R), interleukin-4 receptor (IL-4R), and interleukin-10 receptor (IL-10R) binding domains, and we showed that purified IrmA can bind to their cognate cytokines. Finally, we showed that plasma from convalescent urosepsis patients contains high IrmA antibody titers, demonstrating the strong immunogenicity of IrmA. Taken together, our results indicate that IrmA may play an important role during UPEC infection.

IMPORTANCE
Uropathogenic
E. coli
(UPEC) is the primary cause of urinary tract infection (UTI), a disease of major significance to human health. Globally, the incidence of UPEC-mediated UTI is strongly associated with increasing antibiotic resistance, making this extremely common infection a major public health concern. In this report, we describe the regulatory, structural, functional, and immunogenic properties of a candidate UPEC vaccine antigen, IrmA. We demonstrate that IrmA is a small UPEC protein that forms a unique domain-swapped dimer with structural mimicry to several human cytokine receptors. We also show that IrmA binds to IL-2, IL-4, and IL-10, is strongly immunogenic in urosepsis patients, and is coexpressed with factors associated with biofilm formation. Overall, this work suggests a potential novel contribution for IrmA in UPEC infection.
Impact analysis studies of clinical prediction rules relevant to primary care: a systematic review
Authors: Wallace Emma , Uijen Maike J M , Clyne Barbara , Zarabzadeh Atieh , Keogh Claire , Galvin Rose , Smith Susan M , Fahey Tom
Published: March 2016

Objectives

Following appropriate validation, clinical prediction rules (CPRs) should undergo impact analysis to evaluate their effect on patient care. The aim of this systematic review is to narratively review and critically appraise CPR impact analysis studies relevant to primary care.

Setting

Primary care.

Participants

Adults and children.

Intervention

Studies that implemented the CPR compared to usual care were included.

Study design

Randomised controlled trial (RCT), controlled before–after, and interrupted time series.

Primary outcome

Physician behaviour and/or patient outcomes.

Results

A total of 18 studies, incorporating 14 unique CPRs, were included. The main study design was RCT (n=13). Overall, 10 studies reported an improvement in primary outcome with CPR implementation. Of 6 musculoskeletal studies, 5 were effective in altering targeted physician behaviour in ordering imaging for patients presenting with ankle, knee and neck musculoskeletal injuries. Of 6 cardiovascular studies, 4 implemented cardiovascular risk scores, and 3 reported no impact on physician behaviour outcomes, such as prescribing and referral, or patient outcomes, such as reduction in serum lipid levels. 2 studies examined CPRs in decision-making for patients presenting with chest pain and reduced inappropriate admissions. Of 5 respiratory studies, 2 were effective in reducing antibiotic prescribing for sore throat following CPR implementation. Overall, study methodological quality was often unclear due to incomplete reporting.

Conclusions

Despite increasing interest in developing and validating CPRs relevant to primary care, relatively few have gone through impact analysis. To date, research has focused on a small number of CPRs across few clinical domains only.
Prescription for antibiotics at drug shops and strategies to improve quality of care and patient safety: a cross-sectional survey in the private sector in Uganda
Authors: Mbonye Anthony K , Buregyeya Esther , Rutebemberwa Elizeus , Clarke Siân E , Lal Sham , Hansen Kristian S , Magnussen Pascal , LaRussa Philip
Published: March 2016

Objectives

The main objective of this study was to assess practices of antibiotic prescription at registered drug shops with a focus on upper respiratory tract infections among children in order to provide data for policy discussions aimed at improving quality of care and patient safety in the private health sector in Uganda.

Methods

A survey was conducted within 57 parishes from August to October 2014 in Mukono District, Uganda. Data was captured on the following variables: drug shop characteristics, training of staff in management of pneumonia, availability of guidelines and basic equipment, available antibiotics, knowledge on treatment of pneumonia in children aged <5 years. The main study outcome was the proportion of private health facilities prescribing an antibiotic.

Results

A total of 170 registered drug shops were surveyed between August and October 2014. The majority of drug shops, 93.5% were prescribing antibiotics, especially amoxicillin and trimethoprim-sulfamethoxazole (septrin). The professional qualification of a provider was significantly associated with this practice, p=0.04; where lower cadre staff (nursing assistants and enrolled nurses) overprescribed antibiotics. A third, 29.4% of drug shop providers reported that antibiotics were the first-line treatment for children with diarrhoea; yet the standard guideline is to give oral rehydration salts and zinc tablets. Only few providers, 8.2%, had training on antibiotics, with 10.6% on pneumonia case management. Further to this, 7.1% drug shops had WHO-Integrated Management of Childhood Illness guidelines, and a negligible proportion (<1%) had respiratory timers and baby weighing scales. Although the majority of providers, 82.4%, knew severe signs and symptoms of pneumonia, few, 17.6%, knew that amoxicillin was the first-line drug for treatment of pneumonia in children according to the guidelines.

Conclusions

There is urgent need to regulate drug shop practices of prescribing and selling antibiotics, for the safety of patients seeking care at these outlets.
Architecture of the Canadian portion of the High Arctic Large Igneous Province and implications for magmatic Ni–Cu potential
Authors: Saumur B.M. , Dewing K. , Williamson M.-C.
Published: March 2016

The Cretaceous to Paleogene High Arctic Large Igneous Province (HALIP) occurs in circum-Arctic regions, and the largest portion of the province occurs in Canada’s Arctic Archipelago. This paper reviews and documents the geometry and distribution of the Canadian portion of the HALIP, focussing most notably on the architecture of its intrusive component. The extent of dyke swarms and sills of the Canadian HALIP is updated and is shown to be greater than previously acknowledged. Sills, in particular, occur throughout the Sverdrup Basin and crop out extensively on Axel Heiberg Island within Triassic to Cretaceous strata. The HALIP event is dominantly intrusive, with 3–5 times more intrusive rocks than extrusive rocks, by volume. There is local evidence of syn-emplacement fault activity, possibly involving the reactivation of older faults, controlling the emplacement of dykes. In the eastern Sverdrup Basin, exposures of components of the HALIP are controlled by tectonic elements of the Eocene Eurekan Orogeny, with plumbing systems (dykes, sills) exposed along regional-scale anticlines or the hanging walls of thrusts. Portions of the HALIP have been shown to be prospective for magmatic Ni – Cu – platinum group elements (PGEs) based on geochemistry, and although geochemical controls play a critical role in the genesis of such deposits, structural and magma dynamic controls are also important to consider at the scale of 1–10 km magmatic complexes. Underpinned by the architecture of the Canadian HALIP, we document the structural characteristics of three 1–10 km-scale volcanic–intrusive complexes of the province that show Ni–Cu–PGE prospectivity: the volcanic–intrusive complex of the Strand Fiord – Expedition Fiord area, the Surprise Fiord dykes, and the Wootton Intrusive Complex. All three represent physico-structural environments that would likely promote high magma flowthrough and sulphide transport, and could be targeted for Ni–Cu–PGE magmatic sulphide mineralization.
Can butterflies cope with city life? Butterfly diversity in a young megacity in southern China
Authors: Sing Kong-Wah , Dong Hui , Wang Wen-Zhi , Wilson John-James
Published: March 2016

During 30 years of unprecedented urbanization, plant diversity in Shenzhen, a young megacity in southern China, has increased dramatically. Although strongly associated with plant diversity, butterfly diversity generally declines with urbanization, but this has not been investigated in Shenzhen. Considering the speed of urbanization in Shenzhen and the large number of city parks, we investigated butterfly diversity in Shenzhen parks. We measured butterfly species richness in four microhabitats (groves, hedges, flowerbeds, and unmanaged areas) across 10 parks and examined the relationship with three park variables: park age, park size, and distance from the central business district. Butterflies were identified based on wing morphology and DNA barcoding. We collected 1933 butterflies belonging to 74 species from six families; 20% of the species were considered rare. Butterfly species richness showed weak negative correlations with park age and distance from the central business district, but the positive correlation with park size was statistically significant (p = 0.001). Among microhabitat types, highest species richness was recorded in unmanaged areas. Our findings are consistent with others in suggesting that to promote urban butterfly diversity it is necessary to make parks as large as possible and to set aside areas for limited management. In comparison to neighbouring cities, Shenzhen parks have high butterfly diversity.
Aspects of emergent symmetries
Authors: Gomes Pedro R. S.
Published: March 2016

These are intended to be review notes on emergent symmetries, i.e. symmetries which manifest themselves in specific sectors of energy in many systems. The emphasis is on the physical aspects rather than computation methods. We include some background material and go through more recent problems in field theory, statistical mechanics and condensed matter. These problems illustrate how some important symmetries, such as Lorentz invariance and supersymmetry, usually believed to be fundamental, can arise naturally in low-energy regimes of systems involving a large number of degrees of freedom. The aim is to discuss how these examples could help us to face other complex and fundamental problems.
Detecting Incorrect Uses of Combining Algorithms in XACML 3.0 Policies
Authors: Xu Dianxiang , Shen Ning , Zhang Yunpeng
Published: March 2016

With the increasing complexity of software, new access control methods have emerged to deal with attribute-based authorization. As a standard language for specifying attribute-based access control policies, XACML offers a number of rule and policy combining algorithms to meet different needs of policy composition. Due to their variety and complexity, however, it is not uncommon to apply combining algorithms incorrectly, which can lead to unauthorized access or denial of service. To solve this problem, this paper presents a fault-based testing approach for revealing incorrect combining algorithms in XACML 3.0 policies. The theoretical foundation of this approach relies on the formalization of semantic differences between rule combining algorithms and between policy combining algorithms. It allows the use of a constraint solver for generating queries to which a given policy produces different responses than its combining algorithm-based mutants. Such queries can determine whether or not the given combining algorithm is used correctly. Our empirical studies using various XACML policies have demonstrated that our approach is effective.
Fine-Grained Access Control via XACML Policy Optimization in Cloud Computing
Authors: Pei Xin , Yu Huiqun , Fan Guisheng
Published: March 2016

One primary challenge of enforcing access control in cloud computing is how to ensure access with high efficiency while preserving data security. This paper proposes a fine-grained access control method for cloud resources. The basic idea is to use XACML as access control language and to optimize policies by data fragmentation and policy refinement algorithms. Through data fragmentation, the accessible resources are divided into disjoint data blocks, and each of them will be combined with a set of policy rules. This helps to refine the policy and to avoid data leakage caused by rule conflicting on the resource intersections. Finally, the disjoint data blocks and the optimized policy are distributed in the three-layered cloud, and the decision to a request is made by rule matching on a specific resource rather than traversing the whole policy rules. Experiments show that our proposal enjoys higher efficiency in cloud-based access control.
Antarctic Entomology
Authors: Chown Steven L. , Convey Peter
Published: March 2016

The Antarctic region comprises the continent, the Maritime Antarctic, the sub-Antarctic islands, and the southern cold temperate islands. Continental Antarctica is devoid of insects, but elsewhere diversity varies from 2 to more than 200 species, of which flies and beetles constitute the majority. Much is known about the drivers of this diversity at local and regional scales; current climate and glacial history play important roles. Investigations of responses to low temperatures, dry conditions, and varying salinity have spanned the ecological to the genomic, revealing new insights into how insects respond to stressful conditions. Biological invasions are common across much of the region and are expected to increase as climates become warmer. The drivers of invasion are reasonably well understood, although less is known about the impacts of invasion. Antarctic entomology has advanced considerably over the past 50 years, but key areas, such as interspecific interactions, remain underexplored.
Structure and Evolution of Insect Sperm: New Interpretations in the Age of Phylogenomics
Authors: Dallai Romano , Gottardo Marco , Beutel Rolf Georg
Published: March 2016

This comprehensive review of the structure of sperm in all orders of insects evaluates phylogenetic implications, with the background of a phylogeny based on transcriptomes. Sperm characters strongly support several major branches of the phylogeny of insects—for instance, Cercophora, Dicondylia, and Psocodea—and also different infraordinal groups. Some closely related taxa, such as Trichoptera and Lepidoptera (Amphiesmenoptera), differ greatly in sperm structure. Sperm characters are very conservative in some groups (Heteroptera, Odonata) but highly variable in others, including Zoraptera, a small and morphologically uniform group with a tremendously accelerated rate of sperm evolution. Unusual patterns such as sperm dimorphism, the formation of bundles, or aflagellate and immotile sperm have evolved independently in several groups.
Studying the Complex Communities of Ants and Their Symbionts Using Ecological Network Analysis
Authors: Ivens Aniek B.F. , von Beeren Christoph , Blüthgen Nico , Kronauer Daniel J.C.
Published: March 2016

Ant colonies provide well-protected and resource-rich environments for a plethora of symbionts. Historically, most studies of ants and their symbionts have had a narrow taxonomic scope, often focusing on a single ant or symbiont species. Here we discuss the prospects of studying these assemblies in a community ecology context using the framework of ecological network analysis. We introduce three basic network metrics that we consider particularly relevant for improving our knowledge of ant-symbiont communities: interaction specificity, network modularity, and phylogenetic signal. We then discuss army ant symbionts as examples of large and primarily parasitic communities, and symbiotic sternorrhynchans as examples of generally smaller and primarily mutualistic communities in the context of these network analyses. We argue that this approach will provide new and complementary insights into the evolutionary and ecological dynamics between ants and their many associates, and will facilitate comparisons across different ant-symbiont assemblages as well as across different types of ecological networks.
Gliomas Genomics and Epigenomics: Arriving at the Start and Knowing It for the First Time
Authors: Filbin Mariella G. , Suvà Mario L.
Published: March 2016

Gliomas are the most common primary human brain tumors and occur in both adults and children. Over the past few years, systematic large-scale genomic and epigenomic profiling has provided unprecedented insight into their pathogenesis, uncovering alterations in an unanticipated number of genes and regulatory elements. In this review, we discuss recent discoveries about the genomics and epigenomics of adult and pediatric gliomas and highlight how some of the founding genetic mutations reshape the cancer epigenome. These studies provide an in-depth view of the molecular routes leading to glioma development, offer insight into the cancer stem cell model, help refine classifications, and should lay the foundation for improved clinical care.
Bronchiectasis: Current Concepts in Pathogenesis, Immunology, and Microbiology
Authors: Boyton Rosemary J. , Altmann Daniel M.
Published: March 2016

Bronchiectasis is a disorder of persistent lung inflammation and recurrent infection, defined by a common pathological end point: irreversible bronchial dilatation arrived at through diverse etiologies. This suggests an interplay between immunogenetic susceptibility, immune dysregulation, bacterial infection, and lung damage. The damaged epithelium impairs mucus removal and facilitates bacterial infection with increased cough, sputum production, and airflow obstruction. Lung infection is caused by respiratory bacterial and fungal pathogens, including Pseudomonas aeruginosa, Haemophilus, Aspergillus fumigatus, and nontuberculous mycobacteria. Recent studies have highlighted the relationship between the lung microbiota and microbial-pathogen niches. Disease may result from environments favoring interleukin-17-driven neutrophilia. Bronchiectasis may present in autoimmune disease, as well as conditions of immune dysregulation, such as combined variable immune deficiency, transporter associated with antigen processing–deficiency syndrome, and hyperimmunoglobulin E syndrome. Differences in prevalence across geography and ethnicity implicate an etiological mix of genetics and environment underpinning susceptibility.
Geochemical Insight from Nonlinear Optical Studies of Mineral–Water Interfaces
Authors: Covert Paul A. , Hore Dennis K.
Published: March 2016

The physics and chemistry of mineral–water interfaces are complex, even in idealized systems. Our need to understand this complexity is driven by both pure and applied sciences, that is, by the need for basic understanding of earth systems and for the knowledge to mitigate our influences upon them. The second-order nonlinear optical techniques of second-harmonic generation and sum-frequency generation spectroscopy have proven adept at probing these types of interfaces. This review focuses on the contributions to geochemistry made by nonlinear optical methods. The types of questions probed have included a basic description of the structure adopted by water molecules at the mineral interface, how flow and porosity affect this structure, adsorption of trace metal and organic species, and dissolution mechanisms. We also discuss directions and challenges that lie ahead and the outlook for the continued use of nonlinear optical methods for studies of mineral–water boundaries.
Vibrational Control of Bimolecular Reactions with Methane by Mode, Bond, and Stereo Selectivity
Authors: Liu Kopin
Published: March 2016

Vibrational motions of a polyatomic molecule are multifold and can be as simple as stretches or bends or as complex as concerted motions of many atoms. Different modes of excitation often possess different capacities in driving a bimolecular chemical reaction, with distinct dynamic outcomes. Reactions with vibrationally excited methane and its isotopologs serve as a benchmark for advancing our fundamental understanding of polyatomic reaction dynamics. Here, some recent progress in this area is briefly reviewed. Particular emphasis is placed on the key concepts developed from those studies. The interconnections among mode and bond selectivity, Polanyi's rules, and newly introduced vibrational-induced steric phenomena are highlighted.
Perspectives on the Comparative Study of Electoral Systems
Authors: Grofman Bernard
Published: March 2016

This article considers the potential to use knowledge of expected electoral system effects to engage in electoral engineering. The review focuses on contributions made in the past dozen or so years and is limited to five specific questions: How do electoral systems affect (a) the proportionality of seats–votes relationships, (b) party proliferation, (c) the ideological nature of party competition, (d) voter turnout, and (e) the degree of match between the preferences of citizens and the policy choices of the government?
Formal Models of Nondemocratic Politics
Authors: Gehlbach Scott , Sonin Konstantin , Svolik Milan W.
Published: March 2016

The last decade has witnessed growing interest among political scientists and economists in nondemocratic politics. This trend has been reflected in increasingly rigorous game-theoretic modeling of its various aspects: regime persistence and breakdown, ruling-coalition formation and leadership change, protests and repression, formal institutions and elections, and censorship and media control. We review this research agenda, focusing on the foundational assumptions and political intuition behind key models. Our survey reveals a field populated by disparate models of particular mechanisms that nonetheless share two major analytical themes: asymmetries of information and commitment problems. We propose that future models move toward a genuinely comparative study of authoritarian institutions.
Nukes with Numbers: Empirical Research on the Consequences of Nuclear Weapons for International Conflict
Authors: Gartzke Erik , Kroenig Matthew
Published: March 2016

Research on nuclear security has gone quantitative. Rapid growth in empirical approaches to the consequences of nuclear weapons in recent years promises to settle some controversies, even as it initiates or resurrects debates that may eventually be resolved with better estimates or data. The toolkit for studying nuclear security had long been bereft of quantitative approaches, undermining the virtuous cycle between theory and evidence. New data and growing confidence in statistical approaches have finally produced a systematic empirical literature on the consequences of nuclear weapons. We review existing studies, organizing the literature along thematic lines. We also discuss challenges facing the emergent quantitative literature and suggest several avenues for future research. Although the terminus of the basic research agenda has been anticipated more than once, the literature on nuclear consequences has shown a remarkable ability to generate novel and often unexpected research questions.
Bayes and the Law
Authors: Fenton Norman , Neil Martin , Berger Daniel
Published: March 2016

Although the use of statistics in legal proceedings has considerably grown in the last 40 years, primarily classical statistical methods rather than Bayesian methods have been used. Yet the Bayesian approach avoids many of the problems of classical statistics and is also well suited to a broader range of problems. This article reviews the potential and actual use of Bayes in the law and explains the main reasons for its lack of impact on legal practice. These reasons include misconceptions by the legal community about Bayes' theorem, overreliance on the use of the likelihood ratio, and the lack of adoption of modern computational methods. We argue that Bayesian networks, which automatically produce the necessary Bayesian calculations, provide an opportunity to address most concerns about using Bayes in the law.
Item Response Theory
Authors: Cai Li , Choi Kilchan , Hansen Mark , Harrell Lauren
Published: March 2016

This review introduces classical item response theory (IRT) models as well as more contemporary extensions to the case of multilevel, multidimensional, and mixtures of discrete and continuous latent variables through the lens of discrete multivariate analysis. A general modeling framework is discussed, and the applications of this framework in diverse contexts are presented, including large-scale educational surveys, randomized efficacy studies, and diagnostic measurement. Other topics covered include parameter estimation and model fit evaluation. Both classical (numerical integration based) and more modern (stochastic) parameter estimation approaches are discussed. Similarly, limited information goodness-of-fit testing and posterior predictive model checking are reviewed and contrasted. The review concludes with a discussion of some emerging strands in IRT research such as response time modeling, crossed random effects models, and non-standard models for response processes.
Measuring the intrarenal distribution of glomerular volumes from histological sections
Authors: Hann Bradley D. , Baldelomar Edwin J. , Charlton Jennifer R. , Bennett Kevin M.
Published: March 2016

Glomerular volume is an important metric reflecting glomerular filtration surface area within the kidney. Glomerular hypertrophy, or increased glomerular volume, may be an important marker for renal stress. Current stereological techniques report the average glomerular volume (AVglom) within the kidney. These techniques cannot assess the spatial or regional heterogeneity common in developing renal pathology. Here, we report a novel “unfolding” technique to measure the actual distribution of individual glomerular volumes in a kidney from the two-dimensional glomerulus profiles observed by optical microscopy. The unfolding technique was first developed and tested for accuracy with simulations and then applied to measure the number of glomeruli ( Nglom), AVglom, and intrarenal distribution of individual glomerular volume (IVglom) in the oligosyndactyl (Os/+) mouse model compared with wild-type (WT) controls. The Os/+ mice had fewer and larger glomeruli than WT mice: Nglom was 12,126 ± 1,658 (glomeruli/kidney) in the WT mice and 5,516 ± 899 in the Os/+ mice; AVglom was 2.01 ± 0.28 × 10−4 mm3 for the WT mice and 3.47 ± 0.35 × 10−4 mm3 for the Os/+ mice. Comparing the glomerular volume distributions in Os/+ and WT kidneys, we observed that the Os/+ distribution peaked at a higher value of IVglom than the WT distribution peak, and glomeruli with a radius greater than 55 μm were more prevalent in the Os/+ mice (3.4 ± 1.6% of total glomeruli vs. 0.6 ± 1.2% in WT). Finally, the largest profiles were more commonly found in the juxtamedullary region. Unfolding is a novel stereological technique that provides a new quantitative view of glomerular volume distribution in the individual kidney.
Local and global contributions to hemodynamic activity in mouse cortex
Authors: Pisauro M. Andrea , Benucci Andrea , Carandini Matteo
Published: March 2016

Imaging techniques such as functional magnetic resonance imaging seek to estimate neural signals in local brain regions through measurements of hemodynamic activity. However, hemodynamic activity is accompanied by large vascular fluctuations of unclear significance. To characterize these fluctuations and their impact on estimates of neural signals, we used optical imaging in visual cortex of awake mice. We found that hemodynamic activity can be expressed as the sum of two components, one local and one global. The local component reflected presumed neural signals driven by visual stimuli in the appropriate retinotopic region. The global component constituted large fluctuations shared by larger cortical regions, which extend beyond visual cortex. These fluctuations varied from trial to trial, but they did not constitute noise; they correlated with pupil diameter, suggesting that they reflect variations in arousal or alertness. Distinguishing local and global contributions to hemodynamic activity may help understand neurovascular coupling and interpret measurements of hemodynamic responses.