bluuebunny/crossref_metadata_2025 huggingface dataset:
Oscillations of a liquid bridge resulting from the coalescence of two droplets
Authors: Chireux Véronique , Fabre David , Risso Frédéric , Tordjeman Philippe
Published: June 2015

The inertial oscillations of a bridge of liquid maintained between two disks are studied under condition of negligible gravity. Both experimental and theoretical results are reported. In the experiment, the bridge is formed by the coalescence of two droplets so that its static equilibrium shape is either concave or convex depending on its length. After coalescence, the bridge performs weakly damped oscillations until it reaches its equilibrium shape. Four modes of oscillations are extracted from digital processing of images recorded by means of a high-speed camera. Their frequency and damping rate are determined and found to be independent of the initial conditions that fix the amplitudes of each mode. Concurrently, the eigen modes of oscillations of a non-cylindrical bridge have been computed by assuming inviscid flow and small amplitude oscillations. The agreement between theoretical and measured frequencies confirms that the experimental modes correspond to the eigenmodes of the linear inviscid theory. Their characteristics turn out to be significantly different from that of a cylindrical bridge. In particular, the eigenfrequencies scale as γ/ρRm3, where γ is the surface tension, ρ the liquid density, and Rm the radius at the middle of the bridge, which characterizes the shrunk/swollen character of the mean shape.
Control of ion energy distributions using phase shifting in multi-frequency capacitively coupled plasmas
Authors: Zhang Yiting , Zafar Abdullah , Coumou David J. , Shannon Steven C. , Kushner Mark J.
Published: June 2015

Control of ion energy distributions (IEDs) onto the surface of wafers is an ongoing challenge in microelectronics fabrication. The use of capacitively coupled plasmas (CCPs) using multiple radio frequency (rf) power sources provides many opportunities to customize IEDs. In dual-frequency CCPs using a fundamental frequency and its second harmonic, varying the relative voltages, powers, and phases between the fundamental and second harmonic biases have demonstrated potential as control mechanisms for the shape of the IEDs. In this paper, we report on computational and experimental investigations of IED control in dual-frequency and triple-frequency CCPs where the phase between the fundamental and second harmonic frequency voltage waveform is used as a control variable. The operating conditions were 5–40 mTorr (0.67–5.33 Pa) in Ar and Ar/CF4/O2 gas mixtures. By changing the phase between the applied rf frequency and its second harmonic, the Electrical Asymmetric Effects was significant and not only shifted the dc self-bias but also affected plasma uniformity. When changing phases of higher harmonics, the energies and widths of the IEDs could be controlled. With the addition of a 3rd high-frequency source, the plasma density increased and uniformity improved. Computed results for IEDs were compared with experimental results using an ion energy analyzer in systems using rf phase locked power supplies.
Resonance broadening of argon lines in a micro-scaled atmospheric pressure plasma jet (argon μAPPJ)
Authors: Pipa A. V. , Ionikh Yu. Z. , Chekishev V. M. , Dünnbier M. , Reuter S.
Published: June 2015

Optical emission from atmospheric pressure micro-jet operating with pure argon (argon μAPPJ) flow has been detected with a moderate resolution spectrometer. Large broadening of the several argon (Ar) lines has been observed in the near infrared spectral region. This effect was attributed to resonance broadening of the s2 (Paschen notation) level in 3p54s configuration. In the present work, corresponding line profiles are suggested for plasma diagnostics. For this, a general case of resonance broadening coefficient of noble gases is discussed. As broadening reflects the Ar density, and the static gas pressure of the jet is in equilibrium with the ambient, the local gas temperature can be inferred. An estimation of gas temperature from the width of the 750 nm Ar line is in agreement with rotational temperature of OH radicals determined from the A2Σ+ → X2Π (0, 0) band. At low temperatures (300–600 K) and at partial Ar pressure near atmospheric, the resonance width of the suggested lines is very sensitive to small temperature variations. High temperature sensitivity and large width make the resonance broadened lines very attractive for diagnostics of low temperature discharges at elevated pressure, e.g., as they are used in plasma-medicine.
Accurate characterization and understanding of interface trap density trends between atomic layer deposited dielectrics and AlGaN/GaN with bonding constraint theory
Authors: Ramanan Narayanan , Lee Bongmook , Misra Veena
Published: June 2015

Many dielectrics have been proposed for the gate stack or passivation of AlGaN/GaN based metal oxide semiconductor heterojunction field effect transistors, to reduce gate leakage and current collapse, both for power and RF applications. Atomic Layer Deposition (ALD) is preferred for dielectric deposition as it provides uniform, conformal, and high quality films with precise monolayer control of film thickness. Identification of the optimum ALD dielectric for the gate stack or passivation requires a critical investigation of traps created at the dielectric/AlGaN interface. In this work, a pulsed-IV traps characterization method has been used for accurate characterization of interface traps with a variety of ALD dielectrics. High-k dielectrics (HfO2, HfAlO, and Al2O3) are found to host a high density of interface traps with AlGaN. In contrast, ALD SiO2 shows the lowest interface trap density (<2 × 1012 cm−2) after annealing above 600 °C in N2 for 60 s. The trend in observed trap densities is subsequently explained with bonding constraint theory, which predicts a high density of interface traps due to a higher coordination state and bond strain in high-k dielectrics.
Studies of scintillation properties of CaMoO4 at millikelvin temperatures
Authors: Zhang X. , Lin J. , Mikhailik V. B. , Kraus H.
Published: June 2015

Application of CaMoO4 as a scintillation target in cryogenic rare event searches relies on the understanding of scintillation properties of the material at the temperatures at which these detectors operate. We devised and implemented a detection module with a low-temperature photomultiplier from Hamamatsu (model R8520-06) powered by a Cockcroft-Walton generator. The detector module containing the CaMoO4 crystal was placed in a 3He/4He dilution refrigerator and used to measure scintillation characteristics of CaMoO4 in the millikelvin temperature range. At the lowest temperature achieved, the energy resolution of CaMoO4 for 122 keV γ from a 57Co source is found to be 30%, and the fast and slow decay constants are 40.6 ± 0.8 μs and 3410 ± 50 μs, respectively. The temperature variation of the CaMoO4 decay kinetics is discussed in terms of a three-level model of the emission center.
Comparison of banana flower powder and sodium bicarbonate supplementation on rumen fermentation and milk production in dairy cows
Authors: Kang Sungchhang , Wanapat Metha , Cherdthong Anusorn , Phesatcha Kampanat
Published: June 2015

Four Holstein-Friesian crossbred dairy cows were randomly assigned according to a 2 × 2 factorial arrangement in a 4 × 4 Latin square design to study the effect of banana flower powder (BAFLOP) and sodium bicarbonate (NaHCO3) supplementation as rumen-buffering agents on rumen fermentation and milk production. The first factor was two ratios of roughage to concentrate (R : C) at 60 : 40 and 40 : 60, whereas the second was two sources of buffering agent (BAFLOP and NaHCO3) supplemented at 20 g/kg of dry matter intake. All cows were fed total dry matter intake at 25 g/kg bodyweight and untreated rice straw was used as a roughage source. Feeding R : C at 40 : 60 increased nutrient digestibilities, nitrogen absorption, allantoin excretion and absorption, microbial nitrogen synthesis, microbial crude protein and efficiency of microbial nitrogen synthesis in both BAFLOP- and NaHCO3-supplemented groups. BAFLOP supplementation could maintain ruminal pH as NaHCO3. Blood urea nitrogen, total volatile fatty acid and propionate, and milk yield increased in cows fed R : C at 40 : 60 both in BAFLOP and NaHCO3 supplementation, whereas acetate was relatively high in cows consuming R : C at 60 : 40. However, rumen microorganisms were similar among treatments whereas milk compositions were unchanged by the dietary treatments, except milk fat and total solids were the highest in cow consumed R : C at 60 : 40. The results suggested that feeding R : C at 40 : 60 resulted in improvement of nutrient digestibility, rumen fermentation efficiency and milk production, and supplementation of BAFLOP showed similar buffering capacity as NaHCO3. Therefore, BAFLOP could be used efficiently as a dietary rumen-buffering agent and promisingly deserves a replacement for bicarbonate sources in lactating dairy cows fed on a high concentrate diet.
RhI-Catalyzed Stille-Type Coupling of Diazoesters with Aryl Trimethylstannanes
Authors: Liu Zhen , Xia Ying , Feng Sheng , Wang Shuai , Qiu Di , Zhang Yan , Wang Jianbo
Published: June 2015

A RhI-catalyzed cross-coupling of diazoester with arylstannane was developed. This reaction represents the first Stille-type coupling that uses a diazo compound as the coupling partner. The reaction is operationally simple and can be carried out under mild conditions, thus providing an alternative approach for the synthesis of α-aryl esters. RhI–carbene migratory insertion process is suggested to be involved as the key step in this Stille-type coupling.
Multiscale Prediction of Whirling Disease Risk in the Blackfoot River Basin, Montana: a Useful Consideration for Restoration Prioritization?
Authors: Eby L. A. , Pierce R. , Sparks M. , Carim K. , Podner C.
Published: June 2015

Habitat restoration for inland trout (family Salmonidae) is common across western North America, but planners rarely consider disease risk when prioritizing restoration sites. Whirling disease is a parasitic infection caused by the invasive myxosporean parasite Myxobolus cerebralis and has been implicated in declines of wild trout populations across western North America. For planners to consider disease, disease risk needs to be predictable across the landscape and influence restoration outcomes. We collated the history of whirling disease infection severity scores on the MacConnell–Baldwin scale from sentinel cage studies for hatchery Rainbow Trout Oncorhynchus mykiss in the Blackfoot River basin from 1998 to 2009. At these same sites, we performed reach‐scale geomorphic assessments, derived landscape variables from GIS data layers, and assembled fish composition data. We examined relationships between the severity of infection and several landscape‐scale and reach‐scale variables for 13 basin‐fed streams in the Blackfoot River basin of west‐central Montana using classification and regression tree analyses. In our data set, valley slope and forest cover were the best predictors of fine sediment. Both spring creeks and gently sloping alluvial basin‐fed tributaries to the Blackfoot River basin with higher proportions of fine sediment (particle size < 0.85 mm) were associated with a high severity (≥ grade 3) of infection. Additionally, we explored differences in trout species composition (i.e., susceptible versus resistant species) before and after the whirling disease enzootic using seven basin‐fed streams and two spring creeks. We did not detect trout community shifts from susceptible to disease‐resistant salmonids in basin‐fed disease‐positive streams. However, spring creeks showed a negative trend in disease‐susceptible salmonids after the whirling disease enzootic. Disease risk appears to be predictable across the landscape and may limit possible restoration outcomes by influencing species composition in spring creeks.
Using Next‐Generation Sequencing to Assist a Conservation Hatchery: a Single‐Nucleotide Polymorphism Panel for the Genetic Management of Endangered Delta Smelt
Authors: Lew Ryan M. , Finger Amanda J. , Baerwald Melinda R. , Goodbla Alisha , May Bernie , Meek Mariah H.
Published: June 2015

The Delta Smelt Hypomesus transpacificus, listed as threatened under the California Endangered Species Act, has been cultured at a conservation hatchery since 2008 in response to significant declines in the wild. The conservation hatchery relies on accurate, efficacious, and reproducible molecular techniques to help maintain the captive population's overall genetic diversity and to minimize inbreeding. We created a panel of single‐nucleotide polymorphisms (SNPs) to support broodstock pedigree reconstruction and improve upon current genetic management. For the SNP discovery, we sequenced 27 broodstock samples from the 2012 spawn by using restriction site‐associated DNA sequencing (RAD‐seq). We then created a linkage map by genotyping three single‐pair crosses at 2,317 newly discovered loci with RAD‐seq. We successfully mapped 1,123 loci and identified 26 linkage groups. Fluidigm SNP Type genotyping assays were developed for 104 mapped loci that were selected for minor allele frequencies (MAFs) greater than 0.20, neutrality (Hardy–Weinberg equilibrium), and marker location. Candidates for the genotyping panel were evaluated on a Fluidigm Integrated Fluidic Circuit 96.96 and were tested for marker accuracy and the ability to correctly assign parentage. When applied in conjunction with mating records, we found that a panel of 24 independent SNPs (mean MAF = 0.47) successfully assigned 100% of tested offspring if all of the samples were genotyped at a minimum of 18 loci. Given its capacity to streamline the screening of broodstock candidates, we foresee that the new SNP parentage panel will assume an integral role in genetic management of the Delta Smelt conservation hatchery. Furthermore, genomic resources created for this study have the potential to propel further advances in studying this imperiled species.
Characterization of vacuolar amino acid transporter from Fusarium oxysporum in Saccharomyces cerevisiae
Authors: Lunprom Siriporn , Pongcharoen Pongsanat , Sekito Takayuki , Kawano-Kawada Miyuki , Kakinuma Yoshimi , Akiyama Koichi
Published: June 2015

Fusarium oxysporum causes wilt disease in many plant families, and many genes are involved in its development or growth in host plants. A recent study revealed that vacuolar amino acid transporters play an important role in spore formation in Schizosaccharomyces pombe and Saccharomyces cerevisiae. To investigate the role of vacuolar amino acid transporters of this phytopathogenic fungus, the FOXG_11334 (FoAVT3) gene from F. oxysporum was isolated and its function was characterized. Transcription of FoAVT3 was upregulated after rapamycin treatment. A green fluorescent protein fusion of FoAvt3p was localized to vacuolar membranes in both S. cerevisiae and F. oxysporum. Analysis of the amino acid content of the vacuolar fraction and amino acid transport activities using vacuolar membrane vesicles from S. cerevisiae cells heterologously expressing FoAVT3 revealed that FoAvt3p functions as a vacuolar amino acid transporter, exporting neutral amino acids. We conclude that the FoAVT3 gene encodes a vacuolar neutral amino acid transporter.
It’s Not CSI: The Importance of Forensics for Social Work Education
Authors: ROBBINS SUSAN P. , Vaughan-Eden Viola , Maschi Tina
Published: June 2015

Editorial
Preconditioned eigensolvers for large-scale nonlinear Hermitian eigenproblems with variational characterizations. I. Extreme eigenvalues
Authors: Szyld Daniel , Xue Fei
Published: June 2015

Efficient computation of extreme eigenvalues of large-scale linear Hermitian eigenproblems can be achieved by preconditioned conjugate gradient (PCG) methods. In this paper, we study PCG methods for computing extreme eigenvalues of nonlinear Hermitian eigenproblems of the form

T
(
λ
)
v
=
0

T(\lambda )v=0

that admit a nonlinear variational principle. We investigate some theoretical properties of a basic CG method, including its global and asymptotic convergence. We propose several variants of single-vector and block PCG methods with deflation for computing multiple eigenvalues, and compare them in arithmetic and memory cost. Variable indefinite preconditioning is shown to be effective to accelerate convergence when some desired eigenvalues are not close to the lowest or highest eigenvalue. The efficiency of variants of PCG is illustrated by numerical experiments. Overall, the locally optimal block preconditioned conjugate gradient (LOBPCG) is the most efficient method, as in the linear setting.
Value functions and Dubrovin valuation rings on simple algebras
Authors: Ferreira Mauricio , Wadsworth Adrian
Published: June 2015

In this paper we prove relationships between two generalizations of commutative valuation theory for noncommutative central simple algebras: (1) Dubrovin valuation rings; and (2) the value functions called gauges introduced by Tignol and Wadsworth. We show that if

v
v

is a valuation on a field

F
F

with associated valuation ring

V
V

and

v
v

is defectless in a central simple

F
F

-algebra

A
A

, and

C
C

is a subring of

A
A

, then the following are equivalent: (a) 

C
C

  is the gauge ring of some minimal

v
v

-gauge on

A
A

, i.e., a gauge with the minimal number of simple components of

C

/

J
(
C
)

C/J(C)

; (b) 

C
C

 is integral over

V
V

with

C
=

B
1

∩
…
∩

B
ξ

C = B_1 \cap \ldots \cap B_\xi

where each

B
i

B_i

is a Dubrovin valuation ring of

A
A

with center 

V
V

, and the 

B
i

B_i

 satisfy Gräter’s Intersection Property. Along the way we prove the existence of minimal gauges whenever possible and we show how gauges on simple algebras are built from gauges on central simple algebras.
On generic identifiability of symmetric tensors of subgeneric rank
Authors: Chiantini Luca , Ottaviani Giorgio , Vannieuwenhoven Nick
Published: June 2015

We prove that the general symmetric tensor in

S
d

C

n
+
1

S^d\mathbb {C}^{n+1}

of rank

r
r

is identifiable, provided that

r
r

is smaller than the generic rank. That is, its Waring decomposition as a sum of

r
r

powers of linear forms is unique. Only three exceptional cases arise, all of which were known in the literature. Our original contribution regards the case of cubics (

d
=
3

d=3

), while for

d
≥
4

d\ge 4

we rely on known results on weak defectivity by Ballico, Ciliberto, Chiantini, and Mella.
TPpred3 detects and discriminates mitochondrial and chloroplastic targeting peptides in eukaryotic proteins
Authors: Savojardo Castrense , Martelli Pier Luigi , Fariselli Piero , Casadio Rita
Published: June 2015

Motivation: Molecular recognition of N-terminal targeting peptides is the most common mechanism controlling the import of nuclear-encoded proteins into mitochondria and chloroplasts. When experimental information is lacking, computational methods can annotate targeting peptides, and determine their cleavage sites for characterizing protein localization, function, and mature protein sequences. The problem of discriminating mitochondrial from chloroplastic propeptides is particularly relevant when annotating proteomes of photosynthetic Eukaryotes, endowed with both types of sequences.

Results: Here, we introduce TPpred3, a computational method that given any Eukaryotic protein sequence performs three different tasks: (i) the detection of targeting peptides; (ii) their classification as mitochondrial or chloroplastic and (iii) the precise localization of the cleavage sites in an organelle-specific framework. Our implementation is based on our TPpred previously introduced. Here, we integrate a new N-to-1 Extreme Learning Machine specifically designed for the classification task (ii). For the last task, we introduce an organelle-specific Support Vector Machine that exploits sequence motifs retrieved with an extensive motif-discovery analysis of a large set of mitochondrial and chloroplastic proteins. We show that TPpred3 outperforms the state-of-the-art methods in all the three tasks.

Availability and implementation: The method server and datasets are available at http://tppred3.biocomp.unibo.it.

Contact:  gigi@biocomp.unibo.it

Supplementary information:  Supplementary data are available at Bioinformatics online.
Definitive Radiation Therapy for Stage I-II Endometrial Cancer
Authors: Yoo Stella , Hegarty Sarah E. , Mishra Mark V. , Patel Nirav , Cantrell Leigh A. , Showalter Timothy N.
Published: June 2015

Objective:

There is limited evidence to inform the management of patients with endometrial cancer who are not candidates for hysterectomy, and treatment alternatives have not been compared directly in randomized trials. We analyzed the prognostic factors and outcomes for patients with stage I or II endometrial adenocarcinoma in the National Cancer Institute’s Surveillance, Epidemiology, and End Results public database.

Methods:

We identified a cohort of patients with stage I-II endometrial adenocarcinoma who were managed without hysterectomy and who were diagnosed during 1989 to 2010. Patients with prior primary tumors were excluded. Statistical analyses were performed to test associations between patient characteristics, radiotherapy modality, and overall and endometrial cancer-specific survival. Multivariable analyses were performed to evaluate the impact of radiation therapy (RT) type on survival outcomes after adjusting for other factors.

Results:

Among the 997 women included in the analyses, 605 received no RT (60.7%), 207 (20.8%) received external-beam radiation therapy (EBRT) alone, and 185 (18.6%) received brachytherapy, either alone or in combination with EBRT. After adjusting for other tumor and demographic factors, RT type was not associated with overall or endometrial cancer-specific survival. Significant predictors of survival included: tumor stage and grade, age at diagnosis, and marital status.

Conclusions:

For patients in this population-based cohort with early-stage endometrial cancer managed without hysterectomy, the delivery of brachytherapy was not associated with improved survival, compared with EBRT alone. It seems worthwhile to pursue future clinical trials to evaluate definitive EBRT-alone strategies, omitting brachytherapy, for selected patients with medically inoperable endometrial cancer.
Crosstalk of cardiomyocytes and fibroblasts in co-cultures
Authors: Rother J. , Richter C. , Turco L. , Knoch F. , Mey I. , Luther S. , Janshoff A. , Bodenschatz E. , Tarantola M.
Published: June 2015

Electromechanical function of cardiac muscle depends critically on the crosstalk of myocytes with non-myocytes. Upon cardiac fibrosis, fibroblasts translocate into infarcted necrotic tissue and alter their communication capabilities. In the presentin vitrostudy, we determined a multiple parameter space relevant for fibrotic cardiac tissue development comprising the following essential processes: (i) adhesion to substrates with varying elasticity, (ii) dynamics of contractile function, and (iii) electromechanical connectivity. By combining electric cell-substrate impedance sensing (ECIS) with conventional optical microscopy, we could measure the impact of fibroblast–cardiomyocyte ratio on the aforementioned parameters in a non-invasive fashion. Adhesion to electrodes was quantified via spreading rates derived from impedance changes, period analysis allowed us to measure contraction dynamics and modulations of the barrier resistance served as a measure of connectivity. In summary, we claim that: (i) a preferred window for substrate elasticity around 7 kPa for low fibroblast content exists, which is shifted to stiffer substrates with increasing fibroblast fractions. (ii) Beat frequency decreases nonlinearly with increasing fraction of fibroblasts, while (iii) the intercellular resistance increases with a maximal functional connectivity at 75% fibroblasts. For the first time, cardiac cell–cell junction density-dependent connectivity in co-cultures of cardiomyocytes and fibroblasts was quantified using ECIS.
Tunicates: exploring the sea shores and roaming the open ocean. A tribute to Thomas Huxley
Authors: Lemaire Patrick , Piette Jacques
Published: June 2015

This review is a tribute to the remarkable contributions of Thomas Huxley to the biology of tunicates, the likely sister group of vertebrates. In 1851, the great biologist and philosopher published two landmark papers on pelagic tunicates in thePhilosophical Transactions of the Royal Society. They were dedicated to the description of the adult anatomy and life cycle of thaliaceans and appendicularians, the pelagic relatives of ascidians. In the first part of this review, we discuss the novel anatomical observations and evolutionary hypotheses made by Huxley, which would have a lasting influence on tunicate biology. We also briefly comment on the more philosophical reflections of Huxley on individuality. In the second part, we stress the originality and relevance of past and future studies of tunicates in the resolution of major biological issues. In particular, we focus on the complex relationship between genotype and phenotype and the phenomenon of developmental system drift. We propose that more than 150 years after Huxley's papers, tunicate embryos are still worth studying in their own right, independently of their evolutionary proximity to vertebrates, as they provide original and crucial insights into the process of animal evolution. Tunicates are still at the forefront of biological research.
Bottlenecks in domestic animal populations can facilitate the emergence of
Trypanosoma cruzi
, the aetiological agent of Chagas disease
Authors: Levy Michael Z. , Tustin Aaron , Castillo-Neyra Ricardo , Mabud Tarub S. , Levy Katelyn , Barbu Corentin M. , Quispe-Machaca Victor R. , Ancca-Juarez Jenny , Borrini-Mayori Katty , Naquira-Velarde Cesar , Ostfeld Richard S. ,   and the Chagas Disease Working Group in Arequipa
Published: June 2015

Faeces-mediated transmission of
Trypanosoma cruzi
(the aetiological agent of Chagas disease) by triatomine insects is extremely inefficient. Still, the parasite emerges frequently, and has infected millions of people and domestic animals. We synthesize here the results of field and laboratory studies of
T. cruzi
transmission conducted in and around Arequipa, Peru. We document the repeated occurrence of large colonies of triatomine bugs (more than 1000) with very high infection prevalence (more than 85%). By inoculating guinea pigs, an important reservoir of
T. cruzi
in Peru, and feeding triatomine bugs on them weekly, we demonstrate that, while most animals quickly control parasitaemia, a subset of animals remains highly infectious to vectors for many months. However, we argue that the presence of these persistently infectious hosts is insufficient to explain the observed prevalence of
T. cruzi
in vector colonies. We posit that seasonal rains, leading to a fluctuation in the price of guinea pig food (alfalfa), leading to annual guinea pig roasts, leading to a concentration of vectors on a small subpopulation of animals maintained for reproduction, can propel
T. cruzi
through vector colonies and create a considerable force of infection for a pathogen whose transmission might otherwise fizzle out.
Hosts of avian brood parasites have evolved egg signatures with elevated information content
Authors: Caves Eleanor M. , Stevens Martin , Iversen Edwin S. , Spottiswoode Claire N.
Published: June 2015

Hosts of brood-parasitic birds must distinguish their own eggs from parasitic mimics, or pay the cost of mistakenly raising a foreign chick. Egg discrimination is easier when different host females of the same species each lay visually distinctive eggs (egg ‘signatures’), which helps to foil mimicry by parasites. Here, we ask whether brood parasitism is associated with lower levels of correlation between different egg traits in hosts, making individual host signatures more distinctive and informative. We used entropy as an index of the potential information content encoded by nine aspects of colour, pattern and luminance of eggs of different species in two African bird families (Cisticolidae parasitized by cuckoo finches
Anomalospiza imberbis
, and Ploceidae by diederik cuckoos
Chrysococcyx caprius
). Parasitized species showed consistently higher entropy in egg traits than did related, unparasitized species. Decomposing entropy into two variation components revealed that this was mainly driven by parasitized species having lower levels of correlation between different egg traits, rather than higher overall levels of variation in each individual egg trait. This suggests that irrespective of the constraints that might operate on individual egg traits, hosts can further improve their defensive ‘signatures' by arranging suites of egg traits into unpredictable combinations.
Distributed cognition and social brains: reductions in mushroom body investment accompanied the origins of sociality in wasps (Hymenoptera: Vespidae)
Authors: O'Donnell Sean , Bulova Susan J. , DeLeon Sara , Khodak Paulina , Miller Skye , Sulger Elisabeth
Published: June 2015

The social brain hypothesis assumes the evolution of social behaviour changes animals' ecological environments, and predicts evolutionary shifts in social structure will be associated with changes in brain investment. Most social brain models to date assume social behaviour imposes additional cognitive challenges to animals, favouring the evolution of increased brain investment. Here, we present a modification of social brain models, which we term the distributed cognition hypothesis. Distributed cognition models assume group members can rely on social communication instead of individual cognition; these models predict reduced brain investment in social species. To test this hypothesis, we compared brain investment among 29 species of wasps (Vespidae family), including solitary species and social species with a wide range of social attributes (i.e. differences in colony size, mode of colony founding and degree of queen/worker caste differentiation). We compared species means of relative size of mushroom body (MB) calyces and the antennal to optic lobe ratio, as measures of brain investment in central processing and peripheral sensory processing, respectively. In support of distributed cognition predictions, and in contrast to patterns seen among vertebrates, MB investment decreased from solitary to social species. Among social species, differences in colony founding, colony size and caste differentiation were not associated with brain investment differences. Peripheral lobe investment did not covary with social structure. These patterns suggest the strongest changes in brain investment—a reduction in central processing brain regions—accompanied the evolutionary origins of eusociality in Vespidae.
Leveraging distant relatedness to quantify human mutation and gene conversion rates
Authors: Palamara Pier Francesco , Francioli Laurent , Genovese Giulio , Wilton Peter , Gusev Alexander , Finucane Hilary , Sankararaman Sriram ,   The Genome of the Netherlands Consortium, Sunyaev Shamil , de Bakker Paul I.W. , Wakeley John , Pe’er Itsik , Price Alkes L.
Published: June 2015

The rate at which human genomes mutate is a central biological parameter that has many implications for our ability to understand demographic and evolutionary phenomena. We present a method for inferring mutation and gene conversion rates using the number of sequence differences observed in identical-by-descent (IBD) segments together with a reconstructed model of recent population size history. This approach is robust to, and can quantify, the presence of substantial genotyping error, as validated in coalescent simulations. We applied the method to 498 trio-phased Dutch individuals from the Genome of the Netherlands (GoNL) project, sequenced at an average depth of 13x. We infer a point mutation rate of 1.66 ± 0.04 × 10−8per base per generation, and a rate of 1.26 ± 0.06 × 10−9for < 20 bp indels. Our estimated average genome-wide mutation rate is higher than most pedigree-based estimates reported thus far, but lower than estimates obtained using substitution rates across primates. By quantifying how estimates vary as a function of allele frequency, we infer the probability that a site is involved in non-crossover gene conversion as 5.99 ± 0.69 × 10−6, consistent with recent reports. We find that recombination does not have observable mutagenic effects after gene conversion is accounted for, and that local gene conversion rates reflect recombination rates. We detect a strong enrichment for recent deleterious variation among mismatching variants found within IBD regions, and observe summary statistics of local IBD sharing to closely match previously proposed metrics of background selection, but find no significant effects of selection on our estimates of mutation rate. We detect no evidence for strong variation of mutation rates in a number of genomic annotations obtained from several recent studies.
Sequence evidence for common ancestry of eukaryotic endomembrane coatomers
Authors: Promponas Vasilis J. , Katsani Katerina R. , Blencowe Benjamin J. , Ouzounis Christos A.
Published: June 2015

Eukaryotic cells are defined by compartments through which the trafficking of macromolecules is mediated by large complexes, such as the nuclear pore, transport vesicles and intraflagellar transport. The assembly and maintenance of these complexes is facilitated by endomembrane coatomers, long suspected to be divergently related on the basis of structural and more recently phylogenomic analysis. By performing supervised walks in sequence space across coatomer superfamilies, we uncover subtle sequence patterns that have remained elusive to date, ultimately unifying eukaryotic coatomers by divergent evolution. The conserved residues shared by 3,502 endomembrane coatomer components are mapped onto the solenoid superhelix of nucleoporin and COPII protein structures, thus determining the invariant elements of coatomer architecture. This ancient structural motif can be considered as a universal signature connecting eukaryotic coatomers involved in multiple cellular processes across cell physiology and human disease.
Signatures of Dobzhansky-Muller Incompatibilities in the Genomes of Recombinant Inbred Lines
Authors: Colomé-Tatché Maria , Johannes Frank
Published: June 2015

In the construction of Recombinant Inbred Lines (RILs) from two divergent inbred parents certain genotype (or epigenotype) combinations may be functionally “incompatible” when brought together in the genomes of the progeny, thus resulting in sterility or lower fertility. Natural selection against these epistatic combinations during inbreeding can change haplotype frequencies and distort linkage disequilibrium (LD) relations between loci within and across chromosomes. These LD distortions have received increased experimental attention, because they point to genomic regions that may drive Dobzhansky-Muller-type of reproductive isolation and, ultimately, speciation in the wild. Here we study the selection signatures of two-locus epistatic incompatibility models and quantify their impact on the genetic composition of the genomes of 2-way RILs obtained by selfing. We also consider the biases introduced by breeders when trying to counteract the loss of lines by selectively propagating only viable seeds. Building on our theoretical results, we develop model-based maximum likelihood (ML) tests which can be employed in pairwise genome scans for incompatibility loci using multi-locus genotype data. We illustrate this ML approach in the context of two publishedA.thalianaRIL panels. Our work lays the theoretical foundation for studying more complex systems such as RILs obtained by sibling mating and/or from multi-parental crosses.
Variability in cellular gene expression profiles and homeostatic regulation
Authors: Mishchenko Yuriy
Published: June 2015

One of surprising recent discoveries in biology is that the gene and protein expression profiles in cells with identical genetic and environmental makeup can exhibit large variability. The nature and the significance of this variability had been posed as one of the current fundamental questions of biology. In this letter, we argue that the observed variability in cellular gene and protein expression can be understood as an outcome of homeostatic regulation mechanisms controlling the gene and protein expression profiles.
The role of prosocial and intrinsic motivation in employees’ citizenship behaviour
Authors: Lazauskaite-Zabielske Jurgita , Urbanaviciute Ieva , Bagdziuniene Dalia
Published: June 2015

Purpose

– The purpose of this paper is to examine the role of prosocial and intrinsic motivation and their interaction in predicting employees’ organizational citizenship behaviour (OCB) and its dimensions.

Design/methodology/approach

– In total, 884 employees from Lithuanian public sector were surveyed. The hypotheses were tested using hierarchical regression and moderation analyses.

Findings

– The results revealed that prosocial and intrinsic motivations predicted OCB and its dimensions. Moreover, intrinsic motivation was found to moderate the relationship between prosocial motivation and OCB and four of its dimensions, i.e. intrinsic motivation strengthened the relationship between prosocial motivation and OCB and its dimensions of altruism, courtesy, conscientiousness, and initiative.

Research limitations/implications

– The correlational design of the study does not allow making causal statements. In addition, the sample consisted of public sector employees only; therefore, caution should be made when applying the results to private sector employees. Finally, since all measures were self-reported, the data may suffer from common method bias.

Originality/value

– This study contributes to investigation of motivational antecedents of OCB by revealing the importance of prosocial and intrinsic motivation in predicting employees’ citizenship behaviour.
International banks’ CSR disclosures after the 2008 crisis
Authors: Laidroo Laivi , Sokolova Maia
Published: June 2015

Purpose

– The purpose of this paper is to determine the corporate social responsibility (CSR) disclosure level of 35 international banks across the world at the end of 2013 and analyse the changes in their disclosure patterns compared to 2005 from the institutional perspective.

Design/methodology/approach

– Content analysis of international banks’ web-sites and CSR reports.

Findings

– As expected, CSR disclosure scores of international banks in 2013 were significantly larger than in 2005. Despite addressing the legitimacy gap after the 2008 crisis, significant room for improvements remained in the context of sustainable products, implementation of environmental management policies and introduction of CSR initiatives (the latter especially for Northern American banks). Although the transnational context had contributed to the gradual convergence of CSR disclosure scores, the existence of differing national and organisational contexts had maintained some of the diversity across banks.

Research limitations/implications

– Content analysis approach used limits the possibilities to objectively grasp the depth of CSR and the sample remains biased towards larger international banks headquartered in Europe.

Practical implications

– Stakeholders should remain vary of “window-dressing” attempts and reward only those banks that actually contribute to the society.

Social implications

– Intergovernmental organisations should continue to develop both new and already existing financial sector CSR initiatives to improve the stability of the global financial sector.

Originality/value

– Previous studies have not investigated international banks’ CSR disclosures on broader global samples during the post-2008-crisis period and have not considered the institutional context of their CSR.
Mode I fracture characterization of human bone using the DCB test
Authors: Silva F.G.A. , de Moura M.F.S.F. , Dourado N , Pereira F. A. M. , Morais J.J.L. , Dias M. I. R. , Lourenço Paulo J. , Judas Fernando M.
Published: June 2015

Purpose

– Fracture characterization of human cortical bone under pure mode I loading was performed in this work. The purpose of this paper is to validate the proposed test and procedure concerning fracture characterization of human cortical bone under pure mode I loading.

Design/methodology/approach

– A miniaturized version of the double cantilever beam (DCB) test was used for the experimental tests. A data reduction scheme based on crack equivalent concept and Timoshenko beam theory is proposed to overcome difficulties inherent to crack length monitoring during the test. The application of the method propitiates an easy determination of the Resistance-curves (R-curves) that allow to define the fracture energy under mode I loading from the plateau region. The average value of fracture energy was subsequently used in a numerical analysis with element method involving cohesive zone modelling.

Findings

– The excellent agreement obtained reveals that the proposed test and associated methodology is quite effective concerning fracture characterization of human cortical bone under pure mode I loading.

Originality/value

– A miniaturized version of traditional DCB test was proposed for cortical human bone fracture characterization under mode I loading owing to size restrictions imposed by human femur. In fact, DCB specimen propitiates a longer length for self-similar crack propagation without undertaking spurious effects. As a consequence, a R-curve was obtained allowing an adequate characterization of cortical bone fracture under mode I loading.
“When we say ‘urgent’ it means now …”
Authors: Griffith Laura , Glasby Jon
Published: June 2015

Purpose

– The purpose of this paper is to describe the perceptions which senior health and social care leaders have of their own organisations and of partner agencies, illustrating a possible method for beginning to think and talk about organisational and professional culture in settings.

Design/methodology/approach

– This is a practical case study, with a group of senior leaders from across the health and social care system.

Findings

– Different groups were often more critical of their own organisations than of others, but could still identify certain characteristics that they associated with partner agencies. While there is much that we admire about ourself and others, we seldom get chance to share this positive feedback. Equally, we rarely have the scope to give each other more challenging feedback and this – when carefully facilitated – can help build stronger relationships in the longer term.

Research limitations/implications

– Inter-agency working is often influenced by the implicit assumptions and stereotypes we hold about each other’s professional culture. Surfacing these in a safe, facilitated setting can help to explore and challenge such assumptions (where appropriate), reflect on how we see others and better understand how others see us.

Originality/value

– Policy debates about integrated care too often focus on structural “solutions” and arguably pay insufficient attention to the importance of culture. While work with front-line practitioners often tries to explore different perceptions of each other, it is less common for such an approach to be attempted with senior leaders.
Exploring the use of authentic learning strategies in designing blended learning environments
Authors: Tan Heidi, Yeen-Ju , Neo Mai
Published: June 2015

Purpose

– The aims of this study is to use authentic learning principles outlined by Herrington and Kervin (2007) as an innovative approach towards the development of a blended learning environment in a Malaysian classroom at the tertiary level and students’ perception towards this learning environment was studied.

Design/methodology/approach

– This study was conducted using a mixed-method approach and consisted of two parts. Part A: the learning environment was designed to be student-centred, supported by multimedia and web technologies, consisting of online learning modules, blogs and social media, as well as being driven by a class project. Part B: qualitative and quantitative data were collected to solicit student feedback on the learning environment.

Findings

– Results of the study indicated that students responded positively towards the authentic blended learning environment, as it was found to be relevant to their learning. In an authentic blended learning environment, students became more engaged with the content and actively involved in their learning process. These results show strong and encouraging support for the use of authentic learning principles in the development of blended learning environments.

Originality/value

– Universities in Malaysia are only beginning to move towards a more blended approach in designing learning environments. This paper provides some insights to one possible way of designing a blended learning environment in a Malaysian tertiary setting.
Critical factors inhibiting Electronic Commerce (EC) adoption in Nigeria
Authors: Awa Hart Okorie , Awara Nsobiari Festus , Lebari Eeba Dumka
Published: June 2015

Purpose

– This study aims to develop adoption barriers model that captures location factors and non-transparency in government support programs, and attempted to unveil why certain locations offer more adoption opportunities than others.

Design/methodology/approach

– The opinions of small and medium enterprise (SME) owners/managers in the six geo-political zones of Nigeria were purposefully sampled. Two major cities (the commercial nerve center and a state capital) in each zone were chosen for the study and the data were analyzed using multiple regressions.

Findings

– Irrespective of the need to enhance operations through real-time knowledge sharing and network externalities; evidence from the study shows that SMEs in Nigeria are yet to exploit the full potentials of e-commerce solutions. This is evidenced by non-transparency in government support programs, location factors, weak finances, firm’s size, confidentiality of information, infrastructural inadequacy and lack openness and business integration.

Research limitations/implications

– Sampling the opinions of SMEs in Nigeria limits the power of generalization. Therefore, extended data and measures are required to replicate the study to improve external validity and reliability, and possibly build theories. Also, some errors seem unavoidable in the course of converting data just as all the measures used appear subjective and prone to common method bias.

Originality/value

– Though e-commerce adoption draw-backs enjoy huge literature, location factors and non-transparency in government support programs as critical inhibitors seem least studied. Therefore, this paper complements literature, stimulates future research and advises policymakers on promulgating, and real implementation of, appropriate policy frameworks to create information, communication, technology (ICT)-friendly environment within which e-commerce diffuse amongst SMEs.