bluuebunny/crossref_metadata_2025 huggingface dataset:
Baroclinic vorticity generation near the turbulent/ non-turbulent interface in a compressible shear layer
Authors: Jahanbakhshi R. , Vaghefi N. S. , Madnia C. K.
Published: October 2015

Direct numerical simulations of temporally evolving compressible mixing layers are performed to study the baroclinic vorticity generation due to the interaction between the intense vorticity structures (IVSs) and the turbulent/non-turbulent interface (TNTI). In order to examine this interaction, the vorticity transport across the TNTI and the IVSs in compressible turbulence are studied. The conditional mean budget of different terms in the transport equation of vorticity with respect to the distance from the TNTI is analyzed in the interface coordinate system. In highly compressible mixing layers, it is shown that in proximity of the TNTI, contribution of the baroclinic torque to the total change of vorticity, compared with the other terms in the transport equation of the vorticity, cannot be ignored. The conditional average of the baroclinic torque in the vorticity transport equation reaches a maximum inside the interface layer, with the thickness of approximately one Taylor length scale, at a distance approximately equal to the radius of the IVS from the TNTI. Flow visualization results show that the intense vorticity structures generate a baroclinic torque as they become close to the turbulent/non-turbulent interface. In order to statistically examine the organized interaction between the TNTI and the IVSs, an algorithm described in the Appendix is developed to detect and to study the intense vorticity structures. It is shown that the IVSs generate a pressure gradient from the core of the vortex, low pressure, towards the region outside of the vortex. As the IVSs interact with the TNTI, the pressure gradient vectors become misaligned with the density gradient vectors, which are aligned with the direction normal to the TNTI, and generate a baroclinic torque. It is also observed that compressibility has a small effect on the structural features of the IVSs in the shear layer.
Fabrication of tunable plasmonic substrates using a table-top gold coater and a hot plate, their optical characterization, and surface enhanced Raman activity
Authors: Arora A. , Krishnan A.
Published: October 2015

We present a simple scalable technique for repeatable fabrication of large area (cm2) electromagnetic hot spots using tunable Localized Surface Plasmon Resonance (LSPR) substrates and their k-space microscopic imaging characterization. The substrates were fabricated simply using a low vacuum air plasma scanning electron microscope gold coater and annealing using a hot plate. The measured permittivity profile and optical transmission characteristics of such substrates showed large changes before and after annealing, with clear changes in the occurrence and position of the LSPR in the visible spectrum. Furthermore, the LSPR wavelength of these substrates was tuned from 537 nm to 630 nm using cyclic deposition and annealing. It was observed that every anneal step could be used to blue shift the resonance, while a deposition step could be used to red shift the resonance, thus giving rise to a wide tunability. We also present the k-space images of the substrates using narrowband fluorescence leakage radiation microscopy and broadband polarization microscopy. The enhanced scattering in these substrates was clearly imaged in the k-space, and the color content in the broadband k-space images correlates well with the spectral characteristics of these substrates that can be used in commercial quality testing without a spectrometer. The optical characteristics of the substrates were attributed to the morphology evolution verified using scanning probe microscopy. A single particle model based simulation was used to evaluate the optical response. The substrates were then tested for surface enhanced Raman spectroscopy (SERS) activity using control experiments involving Rhodamine 6G dye in PMMA matrix of different concentrations with analyte volumes of approximately 200 pl and analytical enhancements of >3×104 (net enhancement >1.8×107) were obtained. The limit of detection was ≈ 10−8 M in low volume (≈200 pl) analyte, reaching the regime of few molecule detection. To establish the relevance of the substrates for bio-sensing, surface functionalization using thioglycolic acid was measured using SERS.
Note: Model identification and analysis of bivalent analyte surface plasmon resonance data
Authors: Tiwari Purushottam Babu , Üren Aykut , He Jin , Darici Yesim , Wang Xuewen
Published: October 2015

Surface plasmon resonance (SPR) is a widely used, affinity based, label-free biophysical technique to investigate biomolecular interactions. The extraction of rate constants requires accurate identification of the particular binding model. The bivalent analyte model involves coupled non-linear differential equations. No clear procedure to identify the bivalent analyte mechanism has been established. In this report, we propose a unique signature for the bivalent analyte model. This signature can be used to distinguish the bivalent analyte model from other biphasic models. The proposed method is demonstrated using experimentally measured SPR sensorgrams.
Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density
Authors: Tanaka Hiromasa , Mizuno Masaaki , Toyokuni Shinya , Maruyama Shoichi , Kodera Yasuhiro , Terasaki Hiroko , Adachi Tetsuo , Kato Masashi , Kikkawa Fumitaka , Hori Masaru
Published: October 2015

Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established.
Suppression of current collapse by hole injection from drain in a normally-off GaN-based hybrid-drain-embedded gate injection transistor
Authors: Tanaka Kenichiro , Morita Tatsuo , Umeda Hidekazu , Kaneko Saichiro , Kuroda Masayuki , Ikoshi Ayanori , Yamagiwa Hiroto , Okita Hideyuki , Hikita Masahiro , Yanagihara Manabu , Uemoto Yasuhiro , Takahashi Satoru , Ueno Hiroaki , Ishida Hidetoshi , Ishida Masahiro , Ueda Tetsuzo
Published: October 2015

Current collapse is suppressed up to 800 V of drain voltage in our proposed device, Hybrid-Drain-embedded Gate Injection Transistor (HD-GIT), where an additional p-GaN layer is grown on the AlGaN barrier layer and is connected to the drain electrode. We present, based on a device simulation and electroluminescence study, that the hole injection from the additional drain-side p-GaN at the OFF state compensates the hole emission in the epilayer. As a result, the gate-drain access region is not negatively charged at the OFF state, resulting in the drastic suppression of current collapse in HD-GIT.
Hybrid dispersive media with controllable wave propagation: A new take on smart materials
Authors: Bergamini Andrea E. , Zündel Manuel , Flores Parra Edgar A. , Delpero Tommaso , Ruzzene Massimo , Ermanni Paolo
Published: October 2015

In this paper, we report on the wave transmission characteristics of a hybrid one dimensional (1D) medium. The hybrid characteristic is the result of the coupling between a 1D mechanical waveguide in the form of an elastic beam, supporting the propagation of transverse waves and a discrete electrical transmission line, consisting of a series of inductors connected to ground through capacitors. The capacitors correspond to a periodic array of piezoelectric patches that are bonded to the beam and that couple the two waveguides. The coupling leads to a hybrid medium that is characterized by a coincidence condition for the frequency/wavenumber value corresponding to the intersection of the branches of the two waveguides. In the frequency range centered at coincidence, the hybrid medium features strong attenuation of wave motion as a result of the energy transfer towards the electrical transmission line. This energy transfer, and the ensuing attenuation of wave motion, is alike the one obtained through internal resonating units of the kind commonly used in metamaterials. However, the distinct shape of the dispersion curves suggests how this energy transfer is not the result of a resonance and is therefore fundamentally different. This paper presents the numerical investigation of the wave propagation in the considered media, it illustrates experimental evidence of wave transmission characteristics and compares the performance of the considered configuration with that of internal resonating metamaterials. In addition, the ability to conveniently tune the dispersion properties of the electrical transmission line is exploited to adapt the periodicity of the domain and to investigate diatomic periodic configurations that are characterized by a richer dispersion spectrum and broader bandwidth of wave attenuation at coincidence. The medium consisting of mechanical, piezoelectric, and analog electronic elements can be easily interfaced to digital devices to offer a novel approach to smart materials.
Population genomics ofMycobacterium tuberculosisin the Inuit
Authors: Lee Robyn S. , Radomski Nicolas , Proulx Jean-Francois , Levade Ines , Shapiro B. Jesse , McIntosh Fiona , Soualhine Hafid , Menzies Dick , Behr Marcel A.
Published: October 2015

Significance

Through an in-depth analysis of whole-genome sequencing data from Nunavik, Québec, we inferred the evolution of a single dominant strain ofMycobacterium tuberculosis. Our analyses suggest thatM. tuberculosiswas first introduced into this region in the early 20th century. Since this time,M. tuberculosishas spread extensively, predominantly within but also between villages. Despite a genomic profile that lacks features of a hypervirulent strain, this strain has thrived in this region and continues to cause outbreaks. This suggests that successful clones ofM. tuberculosisneed not be inherently exceptional; host or social factors conducive to transmission may contribute to the ongoing tuberculosis epidemic in this and other high-incidence settings.
The future of airborne sulfur-containing particles in the absence of fossil fuel sulfur dioxide emissions
Authors: Perraud Véronique , Horne Jeremy R. , Martinez Andrew S. , Kalinowski Jaroslaw , Meinardi Simone , Dawson Matthew L. , Wingen Lisa M. , Dabdub Donald , Blake Donald R. , Gerber R. Benny , Finlayson-Pitts Barbara J.
Published: October 2015

Significance

Sulfur dioxide (SO
2
) via its oxidation to sulfuric acid is a major source of airborne particles, which impact visibility, health, and climate. Sources of SO
2
include the combustion of sulfur-containing fossil fuels and the oxidation of organosulfur compounds (OSCs) such as dimethyl sulfide. We show that as fossil fuel combustion is phased out in an urban coastal area, particle formation will decrease substantially but still continue at a reduced rate due to the contribution from OSC oxidation products. Furthermore, methanesulfonic acid generated simultaneously in OSC oxidation will become a significant contributor to particle formation, which should be taken into account in predictive models of air pollution and climate and may be especially important in agricultural areas with significant OSC sources.
Phosphorylation of the Cav3.2 T-type calcium channel directly regulates its gating properties
Authors: Blesneac Iulia , Chemin Jean , Bidaud Isabelle , Huc-Brandt Sylvaine , Vandermoere Franck , Lory Philippe
Published: October 2015

Significance

Ion channels are membrane proteins essential for signal generation and transmission in the nervous system. They are finely regulated, and even small changes in their activity can trigger important physiological or pathological consequences on brain function. A regulatory mechanism of particular importance is phosphorylation. In this study, we assess the impact of phosphorylation on the activity of a specific ion channel, the T-type calcium channel Cav3.2. We show for the first time, to our knowledge, that Cav3.2 is highly phosphorylated in vivo and in a mammalian brain as well as in a human cell line, and we identify many phosphorylation sites critical for the way that the channel opens in response to changes in membrane potential and neuronal excitability.
The evolution of parental cooperation in birds
Authors: Remeš Vladimír , Freckleton Robert P. , Tökölyi Jácint , Liker András , Székely Tamás
Published: October 2015

Significance

Parents in many animal species care for their offspring. In some species, males care more; in other species, females care more; in still other species, the contribution of the sexes is equal. However, we do not know what explains these differences among species. Using the most comprehensive analyses of parental care to date, here we show that parents cooperate more when sexual selection is not intense and the adult sex ratio of males to females is not strongly skewed. However, the degree of parental cooperation is unrelated to harshness and predictability of the ambient environment during the breeding season. Our work therefore suggests that several types of parental care may coexist in a given set of ambient environment.
Topographic representations of object size and relationships with numerosity reveal generalized quantity processing in human parietal cortex
Authors: Harvey Ben M. , Fracasso Alessio , Petridou Natalia , Dumoulin Serge O.
Published: October 2015

Significance

Processing of quantities such as object sizes and numbers relies on analyses of sensory information and informs cognitive tasks such as decision making and mathematics. Whereas sensory processing is organized into topographic maps reflecting sensory organ structure, organization of cognitive processing is poorly understood. We demonstrate topographic representation of object size-tuned responses. This arises separately from object number tuning, but these two quantities are associated in overlapping maps. This generalized quantity representation may allow us to consider object size and number together when making decisions. Optimization of cognitive processing using topographic maps may be a common organizing principle in association cortex, as it is in sensory processing. Linking cognitive representations in maps of related features may support increasingly abstract cognition.
Genetic structure in village dogs reveals a Central Asian domestication origin
Authors: Shannon Laura M. , Boyko Ryan H. , Castelhano Marta , Corey Elizabeth , Hayward Jessica J. , McLean Corin , White Michelle E. , Abi Said Mounir , Anita Baddley A. , Bondjengo Nono Ikombe , Calero Jorge , Galov Ana , Hedimbi Marius , Imam Bulu , Khalap Rajashree , Lally Douglas , Masta Andrew , Oliveira Kyle C. , Pérez Lucía , Randall Julia , Tam Nguyen Minh , Trujillo-Cornejo Francisco J. , Valeriano Carlos , Sutter Nathan B. , Todhunter Rory J. , Bustamante Carlos D. , Boyko Adam R.
Published: October 2015

Significance

Dogs were the first domesticated species, but the precise timing and location of domestication are hotly debated. Using genomic data from 5,392 dogs, including a global set of 549 village dogs, we find strong evidence that dogs were domesticated in Central Asia, perhaps near present-day Nepal and Mongolia. Dogs in nearby regions (e.g., East Asia, India, and Southwest Asia) contain high levels of genetic diversity due to their proximity to Central Asia and large population sizes. Indigenous dog populations in the Neotropics and South Pacific have been largely replaced by European dogs, whereas those in Africa show varying degrees of European vs. indigenous African ancestry.
Vertebrate community on an ice-age Caribbean island
Authors: Steadman David W. , Albury Nancy A. , Kakuk Brian , Mead Jim I. , Soto-Centeno J. Angel , Singleton Hayley M. , Franklin Janet
Published: October 2015

Significance

A flooded sinkhole cave on Abaco (The Bahamas) has yielded the richest (95 species) set of late Pleistocene (ice-age) vertebrates on any Caribbean island. We track changes in species composition on Abaco through time and relate those biotic changes to climate change. The warmer, wetter climate and rising sea levels from 15,000 to 9,000 years ago probably led to the disappearance on Abaco of at least 17 species of birds. Another 22 species of reptiles, birds, and mammals persisted through those environmental changes but did not survive the last 1,000 years of human activity. For the species that remain, we believe that direct human activity threatens their future more than climate change.
Preventing fibril formation of a protein by selective mutation
Authors: Maisuradze Gia G. , Medina Jordi , Kachlishvili Khatuna , Krupa Pawel , Mozolewska Magdalena A. , Martin-Malpartida Pau , Maisuradze Luka , Macias Maria J. , Scheraga Harold A.
Published: October 2015

Significance

Protein folding intermediates are associated with formation of amyloid fibrils, which are responsible for a number of neurodegenerative disorders, such as Alzheimer’s, Parkinson’s, Huntington’s, and Creutzfeldt-Jakob’s diseases. Alzheimer’s disease is one of the largest problems nowadays, with a significant rise in the number and cost (more than $1 trillion a year by 2050 will be spent in the United States alone unless action is taken to shift current trends;
www.alz.org
). Therefore, elucidation of the origins of formation of intermediates and finding ways to prevent them are very important. The presented findings may lead to an understanding of the structural mechanisms by which intermediates initiate fibril aggregation.
Comprehensive analysis reveals how single nucleotides contribute to noncoding RNA function in bacterial quorum sensing
Authors: Rutherford Steven T. , Valastyan Julie S. , Taillefumier Thibaud , Wingreen Ned S. , Bassler Bonnie L.
Published: October 2015

Significance

Five noncoding small RNAs (sRNAs) called the Qrr1-5 sRNAs act at the heart of the
Vibrio harveyi
quorum-sensing cascade. The Qrr sRNAs posttranscriptionally regulate 20 mRNA targets. Here, we use a method we call RSort-Seq that is based on unbiased high-throughput screening to define the critical bases in Qrr4 that specify its function. The power of our study comes from using the screening results to pinpoint particular nucleotides for follow-up biological analyses that define function. Using this approach, we discover how Qrr4 differentially regulates two of its targets,
luxO
and
luxR
. We also show how this strategy can be used to identify intramolecular suppressor mutations. This approach can be applied to any sRNA and any mRNA target.
Head movements in Finnish Sign Language on the basis of Motion Capture data
Authors: Puupponen Anna , Wainio Tuija , Burger Birgitta , Jantunen Tommi
Published: October 2015

This paper reports a study of the forms and functions of head movements produced in the dimension of depth in Finnish Sign Language (FinSL). Specifically, the paper describes and analyzes the phonetic forms and prosodic, grammatical, communicative, and textual functions of nods, head thrusts, nodding, and head pulls occurring in FinSL data consisting of a continuous dialogue recorded with motion capture technology. The analysis yields a novel classification of the kinematic characteristics and functional properties of the four types of head movement. However, it also reveals that there is no perfect correspondence between form and function in the head movements investigated.
Boreal woody species resistance affected by climate change.
Authors: Julkunen-Tiitto R. , Nybakken L. , Randriamanana T. , Virjamo V.
Published: October 2015

Climate change undoubtedly affects the metabolism and resistance of woody plants, and results in changes in their competitive management. Due to low climatic niche evolution, trees and shrubs are slow to react to climate change. In addition, current studies show rather variable results. Therefore, difficulties arise in finding unanimity concerning the impacts of climate change on woody species growth, secondary metabolism and their relationships with other organisms. Here, we review the literature based on current results of the main climate change factors, including increased CO2, temperature and ultraviolet radiation. We summarize the interactions of woody plant growth with defensive metabolism, with a special focus on simultaneously affecting changes.
Abiotic factors, climatic variability and forest insect pests.
Authors: Neuvonen S. , Virtanen T.
Published: October 2015

Abiotic factors have both direct and indirect effects on insects. This chapter focuses on the direct effects of abiotic factors, especially temperature, on insects with different life histories. We draw examples from forest insect pests, mainly from temperate and boreal regions. We also illustrate and discuss several issues relevant for modelling the direct effects of climatic factors on forest insect pests. Abiotic factors can affect the mortality of forest pests in different life stages. Insects are generally well adapted to average conditions during different seasons, but extremes can cause problems. Examples are given from forest defoliators and aphids on conifers. Outbreak distribution and frequency in relation to climatic factors is discussed, with examples from both North America and Europe: the forest tent caterpillar, the spruce budworm and the European pine sawfly. The spatial and temporal resolution used when analysing forest insect outbreaks has often been at greatly larger scales than those at which the relevant ecological processes operate. Consequently, for further work, we stress the importance of considering spatial variation in temperatures when modelling the effects of changing climate on forest pests. Between-year variation in climate is often large in temperate and boreal areas. Examples of the relationships between abiotic factors and forest insects illustrate the multiple ways in which weather can modulate population dynamics. Finally, we discuss the possibilities for predicting the effects of changing abiotic factors on forest insect outbreaks. Multidisciplinary cooperation between researchers in different fields is urgently needed to bridge the gaps between the scales of insect pest dynamics, climate models and data. This is necessary to understand better the impacts of variable and changing climate on forest insect pests.
TLR9 ligation in pancreatic stellate cells promotes tumorigenesis
Authors: Zambirinis Constantinos P. , Levie Elliot , Nguy Susanna , Avanzi Antonina , Barilla Rocky , Xu Yijie , Seifert Lena , Daley Donnele , Greco Stephanie H. , Deutsch Michael , Jonnadula Saikiran , Torres-Hernandez Alejandro , Tippens Daniel , Pushalkar Smruti , Eisenthal Andrew , Saxena Deepak , Ahn Jiyoung , Hajdu Cristina , Engle Dannielle D. , Tuveson David , Miller George
Published: October 2015

Modulation of Toll-like receptor (TLR) signaling can have protective or protumorigenic effects on oncogenesis depending on the cancer subtype and on specific inflammatory elements within the tumor milieu. We found that TLR9 is widely expressed early during the course of pancreatic transformation and that TLR9 ligands are ubiquitous within the tumor microenvironment. TLR9 ligation markedly accelerates oncogenesis, whereas TLR9 deletion is protective. We show that TLR9 activation has distinct effects on the epithelial, inflammatory, and fibrogenic cellular subsets in pancreatic carcinoma and plays a central role in cross talk between these compartments. Specifically, TLR9 activation can induce proinflammatory signaling in transformed epithelial cells, but does not elicit oncogene expression or cancer cell proliferation. Conversely, TLR9 ligation induces pancreatic stellate cells (PSCs) to become fibrogenic and secrete chemokines that promote epithelial cell proliferation. TLR9-activated PSCs mediate their protumorigenic effects on the epithelial compartment via CCL11. Additionally, TLR9 has immune-suppressive effects in the tumor microenvironment (TME) via induction of regulatory T cell recruitment and myeloid-derived suppressor cell proliferation. Collectively, our work shows that TLR9 has protumorigenic effects in pancreatic carcinoma which are distinct from its influence in extrapancreatic malignancies and from the mechanistic effects of other TLRs on pancreatic oncogenesis.
A Hölder estimate for entire solutions to the two-valued minimal surface equation
Authors: Rosales Leobardo
Published: October 2015

We prove a Hölder estimate near infinity for solutions to the two-valued minimal surface equation over

R

2

∖
{
0
}
,

\mathbb {R}^{2} \setminus \{0\},

and give a Bernstein-type theorem in case the solution can be extended continuously across the origin. The main results follow by modifying methods used to study exterior solutions to equations of minimal surface type.
A representation for pseudoholomorphic surfaces in spheres
Authors: Dajczer M. , Vlachos Th.
Published: October 2015

We give a local representation for the pseudoholomorphic surfaces in Euclidean spheres in terms of holomorphic data. Similar to the case of the generalized Weierstrass representation of Hoffman and Osserman for minimal Euclidean surfaces, we assign such a surface in

S

2
n

\mathbb {S}^{2n}

to a given set of

n
n

holomorphic functions defined on a simply-connected domain in

C

\mathbb {C}

.
Behavior and Molecular Genetics of the Five Factor Model
Authors: Jarnecke Amber M. , South Susan C.
Published: October 2015

Behavior and molecular genetics informs knowledge of the etiology, structure, and development of the Five Factor Model (FFM) of personality. Behavior genetics uses quantitative modeling to parse the relative influence of nature and nurture on phenotypes that vary within the population. Behavior genetics research on the FFM has demonstrated that each domain has a heritability (proportion of variation due to genetic influences) of 40–50%. Molecular genetic methods attempt to identify specific genetic mechanisms associated with personality variation. To date, findings from molecular genetics are tentative, with significant results failing to replicate and accounting for only a small percentage of the variance. However, newer techniques hold promise for finding the “missing heritability” of FFM and related personality domains. This chapter presents an overview of commonly used behavior and molecular genetic techniques, reviews the work that has been done on the FFM domains and facets, and offers a perspective for future directions.
Broadening Microstructure Analysis Program(BMAP): an isotropic and anisotropic crystallite size and strain calculator
Authors: Mahmoud E. Khalafalla , Ebeid M. R. , Kaid M. A. , Ali M. G. S.
Published: October 2015

BMAPcalculator is a simplified software tool to obtain microstructure characteristics and to investigate their isotropic and anisotropic nature using some common broadening methods. The Scherrer and Stokes–Wilson methods as well as the Williamson–Hall plot (microstructure isotropy) and modified Williamson–Hall models (strain anisotropy) are implemented in the calculations. TheBMAPinput data are the X-ray diffraction peak parameters (the full width at half-maximum or integral breadth and peak position) of a measured line profile and of a reference one. The components of the measured line profile or corrected broadening are based on several approximations (Cauchy, Gauss or Voigt). The linear least-squares fit is used to calculate the size–strain values, and the correlation coefficient for accepting the results. The calculator is applied to an X-ray diffraction experiment of NiO nanoparticles prepared by a sol–gel method for testing. The results ofBMAPcalculator and theMAUDprogram, combined with an anisotropic Popa rules approach, are compared. The uniform stress model based on the Cauchy approximation is the most suitable one in cubic nanostructure nickel oxide, with an average crystallite size of 24 nm and anisotropic strains of 1.54 × 10−3, 0.61 × 10−3, 1.77 × 10−3and 1.49 × 10−3using the {111}, {200}, {220} and {311} reflections, respectively. Generally, for non-Rietveld users, it is useful to collect different methods into one program to depict the anisotropic nature of materials.
Rietveld analysis of computed tomography and its application to methanol to olefin reactor beds
Authors: Wragg David Stephen , O'Brien Matthew G. , Di Michiel Marco , Lønstad-Bleken Francesca
Published: October 2015

This article reports the creation of tomographic reconstructions giving three-dimensional data on the distribution of various structural features for SAPO-34 zeolite catalyst beds used in the commercially important methanol to olefin conversion process. The data were processed using parametric Rietveld refinement to treat entire slices of the tomograph as single refined data sets, allowing extraction of real structural parameters from all voxels of the reconstruction. This has the advantage over more traditional methods of X-ray diffraction computed tomography using peak intensities, that the structural parameters are independent of the intensity, meaning that information can still be extracted from poor data sets: an example is shown where part of the sample was no longer in the beam during data collection. Reconstructions using several structural parameters are presented and the results compared. Analysis of the variation of the catalystcaxis (linked to the degree of deactivation in earlier work) shows small but significant three-dimensional variations in the degree of deactivation with patterns which depend on the silicon content of the catalyst. Average data for the tomographic slices compare well with the results of earlieroperandotwo-dimensional reactor scanning experiments.
A collaborative optimization framework for parametric and parameter-free variables
Authors: Li W. , Wen Y , Li L X
Published: October 2015

Purpose

– The purpose of this paper is to improve the framework of classical collaborative optimization (CCO) so as to solve the multi-disciplinary optimization problems with parametric and parameter-free variables, and therefore an improved collaborative optimization (ICO) is proposed.

Design/methodology/approach

– To clarify the relation of design variables, the optimization problem is classified into three general case. For each case, the respective treatment is suggested for coupled or uncoupled variables in the framework of the ICO.

Findings

– The decoupling treatment suggested in the ICO framework not only avoids the iteration divergence and thus optimization failure, but increases the optimal design space to some extent. The method is validated by optimizing an aircraft assembly and a high-speed train assembly.

Originality/value

– The two practical examples proves that the present ICO succeeds in solving the problem that the CCO failed to, also gives the optimal results better than those from the sequential optimization method.
An investigation into university extra-curricular enterprise support provision
Authors: Preedy Sarah , Jones Paul
Published: October 2015

Purpose

– The employment market means students need to be equipped with wide-ranging enterprising skills and experience. With small- and medium-sized enterprises crucial to the health of the UK economy providing graduates with the skills to start-up their own business is also of increasing pertinence. The purpose of this paper is to analyse universities’ provision and delivery of student support in developing their enterprise knowledge, skills and experience outside of the curriculum.

Design/methodology/approach

– An e-survey of universities alongside three follow-up semi-structured interviews with participants and an in-depth case study was gathered. The e-survey quantified what enterprise support activities the sample institutions currently offered and the interviews and case study examined the delivery of those activities through the perceptions of university staff/students.

Findings

– The respondents offered a range of enterprise support activity outside of the curriculum but delivery was hindered by a limited means to track proceedings. Support activities were predominantly concentrated both in delivery and receipt within business schools rather than across departments. Support typically consisted of networking events, business advice sessions and workshops as opposed to intensive provisions such as incubation space or start-up loans. The presence and influence of student-led enterprise groups was apparent.

Practical implications

– The results will inform those staff involved in the planning and delivery of enterprise support activity at UK universities.

Originality/value

– This research extends a limited literature mapping extra-curricular enterprise support provision at universities with qualitative data on the delivery of these activities as perceived by staff/students.
The influence of organizational learning culture and perceived organizational support on employees’ affective commitment and turnover intention
Authors: Islam Talat , Ahmed Ishfaq , Ahmad Ungku Norulkamar Bt. Ungku
Published: October 2015

Purpose

– The study aims to examine the relationships between organizational learning culture (OLC), perceived organizational support (POS), affective commitment (AC) and turnover intention (TI) through empirical investigation across the service sector.

Design/methodology/approach

– A total of 758 employees working in the Pakistani banking sector were approached through convenience sampling. A questionnaire-based survey was used to conduct the research.

Findings

– A two-stage approach was applied using structural equation modeling (SEM). In the first stage, confirmatory factor analysis (CFA) was applied, and in the second stage, path coefficients were examined. The study found POS and OLC were positively associated with AC but negatively associated with TI. In addition, SEM confirms that AC performs the role of mediator.

Research limitations/implications

– The study has practical and theoretical implications for HR managers to reduce employees’ TI. Limitations are also discussed.

Originality/value

– The study elucidates the importance of POS and OLC in enhancing AC and reducing TI.
Consumer trust in 3D virtual worlds and its impact on real world purchase intention
Authors: Peng Yan , Ke Dan
Published: October 2015

Purpose

– This paper examines the three-dimensional (3D)virtual world users’ perceptions of authenticity and trustworthiness in the virtual prototypes and users’ potential purchase behavior in the real-world settings. The 3D virtual worlds provide a new platform that exhibits virtual prototypes as a promotion channel for new products of real-world and online service, where users can communicate “face to face” via their representative avatars.

Design/methodology/approach

– The authors conducted an experiment in Second Life and collected data in a post-study questionnaire to test our proposed conceptual model. Structural equation modeling was the main methodology.

Findings

– The research results showed that 3D virtual world users obtained a high sense of telepresence and social presence. The sense of telepresence positively leads to users’ perceptions of online trust in the virtual prototypes and thus increases their intention to purchase real-world objects; the users’ sense of social presence positively associates to their perceptions of authenticity and online trust and, therefore, their purchase intention.

Research limitations/implications

– In survey research, the common method variance is a problem. A more robust way is to use objective measures.

Practical implications

– A new channel was proposed for businesses to enhance their online strategies that will increase their business value.

Social implications

– 3D virtual world is also a cutting-edge platform for remote education, public information service, etc.

Originality/value

– This paper initially contributes to the literature that interprets underlying factors in 3D virtual worlds associated to purchase intention in real-world objects. We demonstrated the advantages, i.e. the communication efficacy and vivid virtual design in the 3D user-generated environment.
A shady business: pine afforestation alters the primary controls on litter decomposition along a precipitation gradient in Patagonia, Argentina
Authors: Araujo Patricia I. , Austin Amy T.
Published: October 2015

Our understanding of the principal controls on litter decomposition is critical for our capacity to predict how global changes will impact terrestrial ecosystems. Although climate, litter quality and soil organisms clearly modulate carbon (C) and nutrient turnover, land‐use change affecting plant species composition and structure can alter the relative importance of such controls.

We took advantage of prior land‐use changes of intentional planting of exotic forest species along a broad precipitation gradient [250–2200 mm mean annual precipitation (MAP)] in Patagonia, South America, where we established five paired sites in natural vegetation and adjacent 35‐year‐old pine plantations. We explored direct and interactive effects of precipitation and plant community structure on litter decomposition within situdecomposition, common litters and reciprocal transplants, in addition to an evaluation of microenvironmental changes.

Surface litter decomposition in natural vegetation (NV) was similar in all sites along the gradient, independent of litter quality,MAPor soil characteristics, while mass loss demonstrated a significant positive linear relationship withMAPin pine plantations (PP).

Decomposition of common litters inPPwas markedly reduced with respect toNV, which was > 50% faster at the arid extreme of the gradient. C:N ratios predicted decomposition only inPP, and differences in decomposition were highly correlated with impacts of vegetative cover on incident solar radiation.

Synthesis. Concurrent changes in plant cover inNVwith increasingMAPresulted in reduced incident solar radiation at the soil surface and decreased the relative importance of photodegradation as a control on surface mass loss. These changes eclipsed direct effects of water availability, litter quality and soil nutrients. In contrast, increased shade and recalcitrant litter with afforestation inPPsites combined such that photodegradation was entirely eliminated as a control and biotic decomposition was much reduced. While afforestation projects are promoted as a strategy to mitigate increased atmospheric carbon dioxide due to human activity, our results highlight that primary controls of litter decomposition were substantially altered with unexpected consequences for the C balance of these ecosystems.
Ground ice melt in the high Arctic leads to greater ecological heterogeneity
Authors: Becker Michael S. , Davies T. Jonathan , Pollard Wayne H.
Published: October 2015

The polar desert biome of the Canadian high Arctic Archipelago is currently experiencing some of the greatest mean annual air temperature increases on the planet, threatening the stability of ecosystems residing above temperature‐sensitive permafrost.

Ice wedges are the most widespread form of ground ice, occurring in up to 25% of the world's terrestrial near‐surface, and their melting (thermokarst) may catalyse a suite of biotic and ecological changes, facilitating major ecosystem shifts.

These unknown ecosystem shifts raise serious questions as to how permafrost stability, vegetation diversity and edaphic conditions will change with a warming high Arctic. Ecosystem and thermokarst processes tend to be examined independently, limiting our understanding of a coupled system whereby the effect of climate change on one will affect the outcome of the other.

Using in‐depth, comprehensive field observations and a space‐for‐time approach, we investigate the highly structured landscape that has emerged due to the thermokarst‐induced partitioning of microhabitats. We examine differences in vegetation diversity, community composition and soil conditions on the Fosheim Peninsula, Ellesmere Island, Nunavut. We hypothesize that (i) greater ice wedge subsidence results in increased vegetation cover due to elevated soil moisture, thereby decreasing the seasonal depth of thaw and restricting groundwater outflow; (ii) thermokarst processes result in altered vegetation richness, turnover and dispersion, with greater microhabitat diversity at the landscape scale; and (iii) shifts in hydrology and plant community structure alter soil chemistry.

We found that the disturbance caused by melting ice wedges catalysed a suite of environmental and biotic effects: topographical changes, a new hydrological balance, significant species richness and turnover changes, and distinct soil chemistries. Thermokarst areas favour a subset of species unique from the polar desert and are characterized by greater species turnover (β‐diversity) across the landscape.

Synthesis. Our findings suggest that projected increases of thermokarst in the polar desert will lead to the increased partitioning of microhabitats, creating a more heterogeneous high arctic landscape through diverging vegetation communities and edaphic conditions, resulting in a wetland‐like biome in the high Arctic that could replace much of the ice‐rich polar desert.
Wind or insect pollination? Ambophily in a subtropical gymnosperm Gnetum parvifolium (Gnetales)
Authors: Gong Yan‐Bing , Yang Min , Vamosi Jana C. , Yang Hong‐Mei , Mu Wei‐Xue , Li Jiao‐Kun , Wan Tao
Published: October 2015

Gnetum (Gnetales) has long been regarded as insect pollinated due to its range‐restricted distribution in tropical rain forests, where wind pollination is supposed to be detrimental. However, ubiquitous pollen limitation in the tropics might cause transition to anemophily, or even ambophily for reproductive assurance, especially for gymnosperms such as Gnetum, which exhibit various anemophilous syndromes, including absence of petals, greenish color of strobili, dioecy and uniovulate flowers. Pollination treatments applied to Gnetum parvifolium in southern China revealed this rare and endangered species to be pollen limited and incapable of apomixis. Pollen grains of G. parvifolium did not adhere to each other and could be trapped by interception traps near the male and female strobili. Seed set in the netted treatment (anemophily) was significantly higher than in the bagged treatment (apomixis) but lower than open pollination (anemophily and entomophily), indicating that both wind and biotic pollination contributed to seed production of G. parvifolium. The occurrence of ambophily in Gnetum and the prevalence of anemophily in Ehpedra and Welwitschia suggest that wind may also play a role in the pollination of the ancient Gnetales.
The Valuation Impact of SEC Enforcement Actions on Nontarget Foreign Firms
Authors: SILVERS ROGER
Published: October 2015

This study shows that the Securities and Exchange Commission's (SEC) enforcement intensity toward the foreign firms under its jurisdiction has increased dramatically over the past two decades. Because enforcement events signify an increased threat of future enforcement, I examine the stock returns of foreign firms not targeted by the SEC during windows around enforcement actions that target foreign firms. This design captures the net effects of public enforcement and helps to rule out omitted variables as alternative explanations, because other factors would have to align with enforcement events that do not occur in an obvious pattern (and are therefore unlikely to map onto other news). Nontarget firms experience positive stock returns during the event windows, which is consistent with enforcement constraining the risks of expropriation. The cross‐sectional pattern in returns reveals greater returns for firms from weak home legal environments. Finally, consistent with the market adjusting to a new enforcement regime, the magnitude of event returns declines over time. Overall, SEC enforcement is associated with increases in the value of foreign firms, supporting the premise of the legal bonding hypothesis.
The Effect of Temperature and Laboratory Rearing Conditions on the Development of Dermestes maculatus (Coleoptera: Dermestidae)
Authors: Zanetti Noelia I. , Visciarelli Elena C. , Centeno Néstor D.
Published: October 2015

Experiments were conducted to study the life cycle of Dermestes maculatus and to establish the total developmental time and the developmental time of immature stages, in relation with six different temperatures. We also analyzed the variations in size, morphology, and other indicators of temporal variation during life cycle of D. maculatus, in relation with temperature. One hundred larvae were selected per experiment, reared individually. The remaining larvae were reared to evaluate and establish temporal variations among the instars (length, cephalic width, and dry weight). In all trials, survivorship was greater than 50% and seven larval instars were found. Data of the average developmental time of immature stages and of the total cycle, at different temperatures, are provided. This is of relevance when estimating particularly, a minimum PMI. No relation between morphometric parameters and temperature was found, suggesting that other random factors may have been involved. Thus, this indicates that the method of isomegalen diagrams could not be used for calculating PMI.
Effects of ranger stations on predator and prey distribution and abundance in anIranian steppe landscape
Authors: Ghoddousi A. , Kh. Hamidi A. , Soofi M. , Khorozyan I. , Kiabi B. H. , Waltert M.
Published: October 2015

Ranger stations are essential to combat poaching in protected areas and the distance from ranger stations is sometimes used as a proxy for poaching levels and law enforcement intensity. However, the influence of the spatial distribution of ranger stations on wildlife abundance and population structure has rarely been investigated. We evaluated the abundance and distribution of urial sheepOvis vigneiandPersian leopardPanthera pardus saxicolorin the steppe ofGolestanNationalPark in northeasternIran. The spatial distribution of these species in regard to anthropogenic (distances to ranger stations, villages and park border) and environmental variables (distance to water resources, average slope and normalized difference vegetation index) was assessed using systematic line transect sampling (186 km) and camera trapping (1150 trap nights). The studied steppe area is divided into three management zones differing in the number of ranger stations and their position with respect to park boundaries. The results of multivariate analyses highlighted that the distance to ranger stations was negatively related to the size and density of urial clusters and the most important variable in explaining urial distribution. Moreover, the distance to park borders influenced urial cluster density. Leopard abundance was positively associated with urial density but was less affected by the other variables tested. We found urial densities in the three management zones to range from 0.15 ± se0.09 individuals km−2(zone with just one station outside the park) to 21.77 ± se7.92 individuals km−2(zone with three stations). Taking into account these results and historical data on ungulate abundance and distribution in these management zones, we conclude that law enforcement from ranger stations has shaped current patterns of ungulate distribution. These results confirm that a good coverage (both numbers and locations) of ranger stations is of central importance for the management of protected areas.