bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of Nd3+ ions on the nucleation and growth of PbS quantum dots (QDs) in silicate glasses
Authors: Park Won Ji , Kim Min Gyu , Kim Ju Eun , Wang Jing , Lee Ho Jeong , Park Chan Gyung , Heo Jong
Published: April 2017

The influence of Nd2O3 addition on the precipitation kinetics of lead chalcogenide (PbS) quantum dots (QDs) in silicate glasses was investigated. Energy dispersive X‐ray spectroscopy (EDS) indicated that the Nd3+ ions are preferentially located inside the PbS QDs rather than in the glass matrix. Changes in diameter (D) of PbS QDs exhibited smaller time dependencies (i.e., D≈t0.270‐0.286) than that predicted by the classical Lifshitz–Slyozov–Wagner (LSW) theory. This is due to the limited concentrations of Pb2+ and S2− ions and the large diffusion distance inside the glass matrix. In addition, extended X‐ray absorption fine structure (EXAFS) results indicated that the formation of PbS QDs was retarded due to the presence of Nd2O3 in the glasses, as the large NdOx polyhedra interrupt the diffusion of Pb2+ and S2− ions. We believe that these Nd3+ ions are primarily located in PbS QDs in the form of Nd–O clusters, and that the PbS QDs are built on top of these clusters.
Electric field tunable thermal stability of energy storage properties of PLZST antiferroelectric ceramics
Authors: Liu Zhen , Dong Xianlin , Liu Yun , Cao Fei , Wang Genshui
Published: April 2017

The electrical hysteresis behaviors and energy storage performance of Pb0.97La0.02(Zr0.58Sn0.335Ti0.085)O3 antiferroelectric (AFE) ceramics were studied under the combined effects of electric field and temperature. It was observed that the temperature dependence of recoverable energy density (Wre) of AFE ceramics depends critically on the applied electric field. While Wre at lower electric fields (<8 kV/mm) shows increasing tendency with increasing temperature from 20°C to 100°C, Wre at higher electric fields (>8 kV/mm) demonstrates decreasing dependence. There exists an appropriate electric field (8 kV/mm) under which the AFE ceramics exhibit nearly temperature‐independent Wre (the variation is less than 0.5% per 10°C). The underlying physical principles were also discussed in this study. These results indicate that the temperature dependence of Wre of AFE materials can be tuned through selecting appropriate electric fields and provide an avenue to obtain thermal stable energy storage capacitors, which should be of great interest to modern energy storage community.
Crystal structure and luminescence properties of a single‐component white‐light‐emitting phosphor Ca8ZnLa(PO4)7:Eu2+,Mn2+
Authors: Mi Ruiyu , Liu Yan‐gai , Mei Lefu , Zhao Chenglong , Chen Jian , Huang Zhaohui , Fang Minghao
Published: April 2017

A series of novel green emission Whitlockite‐type Ca8ZnLa(PO4)7:Eu2+ and color tunable Ca8ZnLa(PO4)7:Eu2+,Mn2+ phosphors were prepared by the solid‐state reaction method in a reducing atmosphere. Its crystal structure and phase composition were identified by high‐resolution transmission electron microscopy, selected area electronic diffraction, X‐ray photoelectron spectroscopy, and X‐ray powder diffraction Rietveld refinement, and it was found to be trigonal, belonging to R‐3c(161) space group. The luminescence properties of Eu2+ singly doped and Eu2+/Mn2+ codoped Ca8ZnLa(PO4)7 phosphors were revealed in detail. Ca8ZnLa(PO4)7:Eu2+ is excitable over a broad range from 200 to 450 nm with a prominent green emitting. With varied Eu2+/Mn2+ ratios, fine‐tune emission under 365 nm excitation can be achieved from green (0.221, 0.468) to magenta (0.391, 0.276), especially the warm white light (0.392, 0.352), and CCT 3500 K can be obtained by the process of energy transfer between Eu2+ and Mn2+. The ET mechanism in this system is managed via the dipole‐dipole interaction with the maximum energy‐transfer efficiency 82.8% based on the decay lifetime data. These results suggest that as‐prepared phosphors can serve as promising candidates of UV‐pumped w‐LEDs.
A comparative analysis of experimental selection on the stickleback pelvis
Authors: Miller S. E. , Barrueto M. , Schluter D.
Published: April 2017

Mechanisms of natural selection can be identified using experimental approaches. However, such experiments often yield nonsignificant effects and imprecise estimates of selection due to low power and small sample sizes. Combining results from multiple experimental studies might produce an aggregate estimate of selection that is more revealing than individual studies. For example, bony pelvic armour varies conspicuously among stickleback populations, and predation by vertebrate and insect predators has been hypothesized to be the main driver of this variation. Yet experimental selection studies testing these hypotheses frequently fail to find a significant effect. We experimentally manipulated length of threespine stickleback (Gasterosteus aculeatus) pelvic spines in a mesocosm experiment to test whether prickly sculpin (Cottus asper), an intraguild predator of stickleback, favours longer spines. The probability of survival was greater for stickleback with unclipped pelvic spines, but this effect was noisy and not significant. We used meta‐analysis to combine the results of our mesocosm experiment with previously published experimental studies of selection on pelvic armour. We found evidence that fish predation indeed favours increased pelvic armour, with a moderate effect size. The same approach found little evidence that insect predation favours reduced pelvic armour. The causes of reduced pelvic armour in many stickleback populations remain uncertain.
Effects of altered photoperiod and temperature on expression levels of gonadotrophin subunit mRNAs in the female stinging catfish Heteropneustes fossilis
Authors: Acharjee A. , Chaube R. , Joy K. P.
Published: April 2017

Differential effects of photoperiod and temperature on the temporal modulation of gonadotrophin subunit genes (glycoprotein α, gpα), follicle‐stimulating hormone β (fshβ) and luteinizing hormone β (lhβ) expression were investigated in the stinging catfish Heteropneustes fossilis. Female H. fossilis were exposed to varying photoperiod and temperature conditions for 14 and 28 days in the early preparatory phase of the annual reproductive cycle. Gonadotrophin subunit gene expression, gonado‐somatic index (IG), ovarian histology and plasma steroid hormone levels were evaluated. The exposure of H. fossilis to long photoperiod (LP) of 16 h light or high temperature (HT) at 28 ± 2° C (mean ± s.e.), alone or in combination, resulted in significant increases in gpα, fshβ and lhβ messenger (m)RNA levels, IG, plasma oestradiol‐17β (E2), testosterone (T) and progesterone (P4) levels. The ovaries were filled with advanced yolky oocytes. On the other hand, the short photoperiod (SP) of 8 h light exposure decreased the transcript levels with higher inhibition in the normal temperature (NT) group at 18 ± 2° C (mean ± s.e.) than the HT group at 28 ± 2° C. Furthermore, the inhibition reached the highest level in total darkness (TD) of 24 h light deprivation under NT conditions at 18 ± 2° C. Consequently, the SP and TD treatments inhibited the IG, plasma E2 and T levels and ovarian development. The exposure to high temperature at 28 ± 2° C also modified the short photoperiod effect by elevating plasma E2 level. The plasma T level changed only mildly while the plasma P4 level showed the greatest fluctuations; the level reached the nadir in the SP + HT group but increased in the SP + NT group on day 28. A two‐way ANOVA of the data showed differential effects of photoperiod and temperature; photoperiod produced a highly significant effect on fshβ expression while temperature had a highly significant effect both on lhβ and gpα levels. Thus, the differential expression of the gpα by the environmental variables ensures temporal synchronization of ovarian development and spawning.
Displacement of native white‐spotted charr Salvelinus leucomaenis by non‐native brown trout Salmo trutta after resolution of habitat fragmentation by a migration barrier
Authors: Hasegawa K.
Published: April 2017

After resolution of habitat fragmentation by an erosion‐control dam, non‐native brown trout Salmo trutta invaded the upstream side of the dam and displaced native white‐spotted charr Salvelinus leucomaenis in Monbetsu stream, Hokkaido, northern Japan.
Real‐World Clinical Characteristics and Treatment Patterns of Individuals Aged 80 and Older with Nonvalvular Atrial Fibrillation: Results from the ReAl‐life Multicenter Survey Evaluating Stroke Study
Authors: Biteker Murat , Başaran Özcan , Doğan Volkan , Altun İbrahim , Özpamuk Karadeniz Fatma , Tekkesin Ahmet İlker , Çakıllı Yasin , Türkkan Ceyhan , Hamidi Mehmet , Demir Vahit , Gürsoy Mustafa Ozan , Tek Öztürk Müjgan , Aksan Gökhan , Seyis Sabri , Ballı Mehmet , Alıcı Mehmet Hayri , Bozyel Serdar
Published: April 2017

Objectives

To compare the clinical characteristics of and use of oral anticoagulant (OAC) therapy in individuals aged 80 and older with atrial fibrillation (AF) with those of individuals younger than 80 withAFin clinical practice.

Design

Observational study.

Setting

The ReAl‐life Multicenter Survey Evaluating Stroke prevention strategies in Turkey trial (NCT02344901), a national observational registry.

Participants

Turkish adults with nonvalvularAF(NVAF).

Measurements

Age data were collected at the time of entry into the registry and the octogenarian subgroup included all patients aged ≥ 80 years. We compared background and management in octogenarian with non‐octogenarian AF patients.

Results

Fifty‐seven cardiology units enrolled 6,273 individuals in 3 months. Participants aged 80 and older (n = 1,170) were more likely to be female (60.7% vs 54.7%,P < .001) and had a higher prevalence of persistant or permanentAF, comorbidities, history of cerebral vascular accident, and major bleeding. As a consequence of having more comorbidities, Congestive heart failure; Hypertension; Aged 75 and older; Diabetes Mellitus; prior stroke, transient ischemic attack, or thromboembolism; Vascular disease; Aged 65 to 74; female Sex (CHA2DS2VASc) (4.32 ± 1.35 vs 3.04 ± 1.54,P < .001) and Hypertension, Abnormal renal and liver function, Stroke, Bleeding, Labile international normalized ratio, Elderly, Drugs or alcohol (HAS‐BLED) (2.14 ± 1.05 vs 1.54 ± 1.05,P < .001) scores were higher in those aged 80 and older. The mean time in therapeutic range of individuals who were taking warfarin was lower in those aged 80 and older (45.9 ± 27.9) than in those younger than 80 (54.7 ± 24.9%,P < .001). Anticoagulant therapy was prescribed for 74.8% of participants younger than 80% and 63% of those aged 80 and older (P < .001). HigherCHA2DS2VASc score and lowerHAS‐BLEDscore were independent predictors ofOACprescription in participants aged 80 and older.

Conclusion

Nearly one‐fifth of individuals withNVAFin this real‐world sample were aged 80 and older. Participants aged 80 and older were more likely to be female and have more comorbidities than those who were younger than 80. Those aged 80 and older withAFwere less likely to receive anticoagulants than those who were younger than 80, but having more comorbidities and other individual‐level characteristics may explain this difference. When they were prescribedOACs, participants aged 80 and older had poorer quality of anticoagulation than those who were younger, suggesting opportunities for improvement.
“We will never be normal”: The Experience of Discovering a Partner Has Autism Spectrum Disorder
Authors: Lewis Laura F.
Published: April 2017

Online forums and lay literature suggest that partners of individuals with Autism Spectrum Disorder (ASD) experience depression, distress, and trauma in their everyday lives, exacerbated during the time surrounding diagnosis. In this content analysis, 29 participants were provided with an online open‐ended statement asking them to describe in writing their experiences of discovering that their partners had ASD during their relationships. Six themes emerged, including: facing unique challenges within relationships; insisting partners seek diagnosis; initial shock and relief; losing hope for normalcy; making accommodations within relationships; and wishing for professional support. Marriage and family therapists should help couples minimize blaming and promote self‐awareness, appropriate relationship expectations, and mutual understanding. Future research should explore the overall experience of neuro‐mixed relationships for both partners.
Petrogenetic relations among titanium‐rich minerals in an anatectic high‐P mafic granulite
Authors: Marsh J.H. , Kelly E.D.
Published: April 2017

The petrogenetic relations among Ti‐rich minerals in high‐grade metabasites is illuminated here through a detailed petrological investigation of an anatectic garnet–clinopyroxene granulite from the Grenville Province, Ontario, Canada containing rutile, titanite and ilmenite in distinct microtextural settings. Garnet porphyroblasts exhibit zoned Ti concentrations (up to 0.15 wt% TiO2 in their cores), as well as a variety of rutile inclusion types, including clusters of small, variably elongate grains and thin (≤1 μm) oriented needles. Calcite inclusions in garnet, commonly observed surrounding garnet cores containing quartz and clinozoisite, indicate the presence of evolving C–O–H fluids during garnet growth and suggest that the rutile clusters may have formed from subsequent Ti diffusion and rutile precipitation within existing fluid inclusions. Titanite forms large subhedral crystals and typically occurs where the primary garnet–clinopyroxene assemblage is in contact with leucosome containing megacrystic hornblende, silvialitic scapolite and calcic plagioclase. Many titanite crystals exhibit marginal subgrains that correspond with sharp changes in their major and trace element composition, likely related to a dissolution–precipitation or recrystallization process following primary crystallization. Clinopyroxene–ilmenite symplectite coronas surround titanite in most locations, likely forming from reaction with the hornblende‐plagioclase matrix (±fluids/melt). Integration of multi‐equilibria thermobarometry and Zr thermometry in rutile and titanite with phase equilibrium modelling allows definition of a clockwise P–T path evolving to peak pressures of ~1.5 GPa at ~750°C during garnet and rutile growth, followed by peak temperature conditions of ~1.2 GPa and ~820–880°C associated with melt‐present titanite growth, and finally cooling and decompression to regional amphibolite facies conditions (~1.0 GPa and ~750°C) associated with the formation of clinopyroxene–ilmenite symplectites surrounding titanite. P–T pseudosections calculated for the pristine (leucosome‐ and titanite ‐free) metabasite bulk composition reproduce much of the prograde phase relations, but predict rutile as the stable Ti‐rich mineral at the peak thermal conditions associated with melt‐present titanite growth. The P–M(CaO) and T–M(CaO) models show that bulk CaO concentrations have a significant effect on the stability ranges of titanite and rutile. Increased bulk CaO tends to stabilize titanite to higher pressure and temperature at the expense of rutile, with a ≥15% increase in CaO producing the observed titanite‐bearing assemblage at high‐P granulite facies conditions. Thus, the model results are consistent with the textural observations, which suggest that titanite stability is associated with a chemical exchange between the host metabasite and a Ca‐rich melt.
Fast ‘Operando’ electron nanotomography
Authors: ROIBAN L. , LI S. , AOUINE M. , TUEL A. , FARRUSSENG D. , EPICIER T.
Published: April 2017

Electron tomography in transmission electron microscopy provides valuable three‐dimensional structural, morphological and chemical information of condensed matter at nanoscale. Current image acquisitions require at least tens of minutes, which prohibits the analysis of nano‐objects evolving rapidly such as under dynamic environmental conditions. Reducing the acquisition duration to tens of seconds or less permits to follow in 3D the same object during its evolution under varying temperatures and pressures. We report Operando Electron nanotomography using image series acquired in less than 230 seconds instead of typically 15 min in the best cases so far. The in situ calcination of silica zeolites encaging silver nanoparticles, a catalytic nanosystem of potential interest for, e.g., nuclear waste treatments or selective heterogeneous catalysis, was successfully studied. Kinetic environmental Operando 3D electron microscopy becomes possible, as well as real time observation of beam sensitive samples (polymers, biological objects) without prior preparation, which reduces their contrast and reactivity.
Intestinal alkaline phosphatase at the crossroad of intestinal health and disease – a putative role in type 1 diabetes
Authors: Lassenius M. I. , Fogarty C. L. , Blaut M. , Haimila K. , Riittinen L. , Paju A. , Kirveskari J. , Järvelä J. , Ahola A. J. , Gordin D. , Härma M.‐A. , Kumar A. , Hamarneh S. R. , Hodin R. A. , Sorsa T. , Tervahartiala T. , Hörkkö S. , Pussinen P. J. , Forsblom C. , Jauhiainen M. , Taskinen M.‐R. , Groop P.‐H. , Lehto M. ,   the FinnDiane Study Group
Published: April 2017

Background

Patients with type 1 diabetes have shown an increase in circulating cytokines, altered lipoprotein metabolism and signs of vascular dysfunction in response to high‐fat meals. Intestinal alkaline phosphatase (IAP) regulates lipid transport and inflammatory responses in the gastrointestinal tract. We therefore hypothesized that changes in IAP activity could have profound effects on gut metabolic homeostasis in patients with type 1 diabetes.

Methods

Faecal samples of 41 nondiabetic controls and 46 patients with type 1 diabetes were analysed for IAP activity, calprotectin, immunoglobulins and short‐chain fatty acids (SCFAs). The impact of oral IAP supplementation on intestinal immunoglobulin levels was evaluated in C57BL/6 mice exposed to high‐fat diet for 11 weeks.

Results

Patients with type 1 diabetes exhibited signs of intestinal inflammation. Compared to controls, patients with diabetes had higher faecal calprotectin levels, lower faecal IAP activities accompanied by lower propionate and butyrate concentrations. Moreover, the amount of faecal IgA and the level of antibodies binding to oxidized LDL were decreased in patients with type 1 diabetes. In mice, oral IAP supplementation increased intestinal IgA levels markedly.

Conclusion

Deprivation of protective intestinal factors may increase the risk of inflammation in the gut – a phenomenon that seems to be present already in patients with uncomplicated type 1 diabetes. Low levels of intestinal IgA and antibodies to oxidized lipid epitopes may predispose such patients to inflammation‐driven complications such as cardiovascular disease and diabetic nephropathy. Importantly, oral IAP supplementation could have beneficial therapeutic effects on gut metabolic homeostasis, possibly through stimulation of intestinal IgA secretion.
Early stages in the ontogeny of small B‐cell lymphomas: genetics and microenvironment
Authors: Ghia P. , Nadel B. , Sander B. , Stamatopoulos K. , Stevenson F. K.
Published: April 2017

In this review, we focus on the mechanisms underlying lymphomagenesis in chronic lymphocytic leukaemia, follicular lymphoma, mantle cell lymphoma and splenic marginal zone lymphoma. The cells of origin of these small B‐cell lymphomas are distinct, as are the characteristic chromosomal lesions and clinical courses. One shared feature is retention of expression of surface immunoglobulin. Analysis of this critical receptor reveals the point of differentiation reached by the cell of origin. Additionally, the sequence patterns of the immunoglobulin‐variable domains can indicate a role for stimulants of the B‐cell receptor before, during and after malignant transformation. The pathways driven via the B‐cell receptor are now being targeted by specific kinase inhibitors with exciting clinical effects. To consider routes to pathogenesis, potentially offering earlier intervention, or to identify causative factors, genetic tools are being used to track pretransformation events and the early phases in lymphomagenesis. These methods are revealing that chromosomal changes are only one of the many steps involved, and that the influence of surrounding cells, probably multiple and variable according to tissue location, is required, both to establish tumours and to maintain growth and survival. Similarly, the influence of the tumour microenvironment may protect malignant cells from eradication by treatment, and the resulting minimal residual disease will eventually give rise to relapse. The common and different features of the four lymphomas will be summarized to show how normal B lymphocytes can be subverted to generate tumours, how these tumours evolve and how their weaknesses can be attacked by targeted therapies.
Human capital accumulation and long‐term income growth projections for European regions
Authors: Cuaresma Jesús Crespo , Doppelhofer Gernot , Huber Florian , Piribauer Philipp
Published: April 2017

We propose an econometric framework to construct projections for per capita income growth and human capital for European regions. Using Bayesian methods, our approach accounts for model uncertainty in terms of the choice of explanatory variables, the nature of spatial spillovers, as well as the potential endogeneity between output growth and human capital accumulation. This method allows us to assess the potential contribution of future educational attainment to economic growth and income convergence among European regions over the next decades. Our findings suggest that income convergence dynamics and human capital act as important drivers of income growth for the decades to come.
Religious Ambivalence, Liminality, and the Increase of No Religious Preference in the United States, 2006–2014
Authors: Hout Michael
Published: April 2017

Americans identified less and less with organized religion over the past two decades. Yet apparently, many people who no longer identify with a religion are not consistently nonreligious. Reinterviews reveal that many people who express no religious preference in one survey name a religion when asked the same question in a subsequent interview. Past research called this phenomenon a “liminal” status. This article improves estimates of liminality by using three interviews and a better statistical model. About 20 percent of Americans were liminal in recent years, 10 percent were consistently nonreligious, and 70 percent were consistently religious. Falling religious identification in cross‐sectional data over the last three decades reflects slow change in religious identity, but some of the rise of the nones is due to more liminals saying they have no religion. Liminals appear equally among people raised conservative Protestant, mainline Protestant, or Catholic.
The Increasing Irrelevance of Trade Diversion
Authors: Magee Christopher S.P.
Published: April 2017

This paper is intended as a guide for policymakers considering new regional trade agreements. The data provided here show that only about a quarter of imports are potentially subject to trade diversion from new agreements (i.e. they come from countries outside of regional trading blocs and in industries with positive most‐favored nation tariffs). Since this percentage is steadily declining with the increasing number of regional trade agreements and the falling level of tariffs, trade diversion is becoming increasingly irrelevant as a concern for new trade deals. The paper also estimates how each potential new bilateral free trade agreement would affect a country's imports and exports, as well as whether the increased imports would replace domestic production, imports from other RTA partners, or imports from non‐RTA partners. In this way, the estimates are able to shed light on which countries make the best partners for new regional trade agreements. Finally, the paper provides estimates of the trade effects for two large potential new regional agreements: the Transatlantic Trade and Investment Partnership and the Trans‐Pacific Partnership.
Public Corruption in the U.S. States and Its Impact on Public Debt Pricing
Authors: Moldogaziev Tima T. , Liu Cheol , Luby Martin J.
Published: April 2017

This study evaluates the levels of public corruption in the American states and their impact on the prices of public debt sold by underwriting banks to retail investors. Results suggest that the markups paid by retail investors to underwriters decrease significantly with the incidence of public corruption. The relationship remains significant even when existing anti‐corruption enforcement efforts are taken into consideration. Extant literature shows that the issuers of public debt from relatively more corrupt jurisdictions receive lower prices from underwriting banks in wholesale transactions. We develop and empirically show the mechanism through which this can occur. We offer the first evidence that the public debt market exerts disciplining pressures on the American states with greater levels of public corruption. When purchasing state‐issued public debt, retail buyers appear to demand narrower markups by factoring in public corruption. This, we argue, is an important reason why underwriting banks offer lower prices when dealing with less disciplined fiscal sovereigns.
Abandoning Fossil Fuel: How Fast and How Much
Authors: Rezai Armon , Van Der Ploeg Frederick
Published: April 2017

Keeping climate change within limits requires that most of the available carbon‐based energy sources need to be abandoned underground. We study how fast and how much this transition to carbon‐free energy needs to occur within a welfare‐maximizing Ramsey growth model of climate change. Our model also addresses the market failure in the development of clean energy which leads to an under‐provision of renewable energy, delays the transition time to the carbon‐free era and reduces the amount of dirty fuels locked upin situ. Optimal policy requires an aggressive renewables subsidy in the near term and a gradually rising carbon tax which falls in long run. We also study the transition timing and the performance of recently proposed policy rules for the carbon tax.
Role of seed germination in adaptation and reproductive isolation in Arabidopsis lyrata
Authors: Hämälä Tuomas , Mattila Tiina M. , Leinonen Päivi H. , Kuittinen Helmi , Savolainen Outi
Published: April 2017

Seed germination is an important developmental and life history stage. Yet, the evolutionary impact of germination has mainly been studied in the context of dormancy, or for its role in reproductive isolation between species. Here, we aim to examine multiple consequences of genetic divergence on germination traits between two Arabidopsis lyrata subspecies: ssp. petraea (Eurasia) and ssp. lyrata (North America). Postdormancy germination time, a potentially adaptive trait, showed differentiation between the populations, and quantitative trait loci (QTL) mapping revealed that the trait variation is mainly controlled by two antagonistic loci. These QTL areas contain several candidate genes with known function in postdormancy germination in A. thaliana. The sequence variation of three genes was consistent with differential selection, and they also included fixed nonsynonymous substitutions with potential to account for the phenotypic differentiation. We further show that the divergence between the subspecies has led to a slight but significant reduction in hybrid germination proportions, indicating incipient reproductive isolation. Comparison of reciprocal F1 and F2 progenies suggests that Bateson–Dobzhansky–Muller incompatibilities likely act through uniparentally inherited factors. Examination of genomewide transmission ratio distortion further revealed that cytonuclear interactions cause substantial pregermination inviability in the hybrids. These results confirm that seed germination has adaptive potential beyond the dormancy stage and that hybrid seed inviability can be one of the first reproductive barriers to arise during divergence.
The structured diversity of specialized gut symbionts of the New World army ants
Authors: Łukasik Piotr , Newton Justin A. , Sanders Jon G. , Hu Yi , Moreau Corrie S. , Kronauer Daniel J. C. , O'Donnell Sean , Koga Ryuichi , Russell Jacob A.
Published: April 2017

Symbiotic bacteria play important roles in the biology of their arthropod hosts. Yet the microbiota of many diverse and influential groups remain understudied, resulting in a paucity of information on the fidelities and histories of these associations. Motivated by prior findings from a smaller scale, 16S rRNA‐based study, we conducted a broad phylogenetic and geographic survey of microbial communities in the ecologically dominant New World army ants (Formicidae: Dorylinae). Amplicon sequencing of the 16S rRNA gene across 28 species spanning the five New World genera showed that the microbial communities of army ants consist of very few common and abundant bacterial species. The two most abundant microbes, referred to as Unclassified Firmicutes and Unclassified Entomoplasmatales, appear to be specialized army ant associates that dominate microbial communities in the gut lumen of three host genera, Eciton, Labidus and Nomamyrmex. Both are present in other army ant genera, including those from the Old World, suggesting that army ant symbioses date back to the Cretaceous. Extensive sequencing of bacterial protein‐coding genes revealed multiple strains of these symbionts coexisting within colonies, but seldom within the same individual ant. Bacterial strains formed multiple host species‐specific lineages on phylogenies, which often grouped strains from distant geographic locations. These patterns deviate from those seen in other social insects and raise intriguing questions about the influence of army ant colony swarm‐founding and within‐colony genetic diversity on strain coexistence, and the effects of hosting a diverse suite of symbiont strains on colony ecology.
Accounting for linkage disequilibrium in genome scans for selection without individual genotypes: The local score approach
Authors: Fariello María Inés , Boitard Simon , Mercier Sabine , Robelin David , Faraut Thomas , Arnould Cécile , Recoquillay Julien , Bouchez Olivier , Salin Gérald , Dehais Patrice , Gourichon David , Leroux Sophie , Pitel Frédérique , Leterrier Christine , SanCristobal Magali
Published: April 2017

Detecting genomic footprints of selection is an important step in the understanding of evolution. Accounting for linkage disequilibrium in genome scans increases detection power, but haplotype‐based methods require individual genotypes and are not applicable on pool‐sequenced samples. We propose to take advantage of the local score approach to account for linkage disequilibrium in genome scans for selection, cumulating (possibly small) signals from single markers over a genomic segment, to clearly pinpoint a selection signal. Using computer simulations, we demonstrate that this approach detects selection with higher power than several state‐of‐the‐art single‐marker, windowing or haplotype‐based approaches. We illustrate this on two benchmark data sets including individual genotypes, for which we obtain similar results with the local score and one haplotype‐based approach. Finally, we apply the local score approach to Pool‐Seq data obtained from a divergent selection experiment on behaviour in quail and obtain precise and biologically coherent selection signals: while competing methods fail to highlight any clear selection signature, our method detects several regions involving genes known to act on social responsiveness or autistic traits. Although we focus here on the detection of positive selection from multiple population data, the local score approach is general and can be applied to other genome scans for selection or other genomewide analyses such as GWAS.
Wide but not impermeable: Testing the riverine barrier hypothesis for an Amazonian plant species
Authors: Nazareno Alison G. , Dick Christopher W. , Lohmann Lúcia G.
Published: April 2017

Wallace's riverine barrier hypothesis postulates that large rivers, such as the Amazon and its tributaries, reduce or prevent gene flow between populations on opposite banks, leading to allopatry and areas of species endemism occupying interfluvial regions. Several studies have shown that two major tributaries, Rio Branco and Rio Negro, are important barriers to gene flow for birds, amphibians and primates. No botanical studies have considered the potential role of the Rio Branco as a barrier, while a single botanical study has evaluated the Rio Negro as a barrier. We studied an Amazon shrub, Amphirrhox longifolia (A. St.‐Hil.) Spreng (Violaceae), as a model to test the riverine barrier hypothesis. Twenty‐six populations of A. longifolia were sampled on both banks of the Rio Branco and Rio Negro in the core Amazon Basin. Double‐digest RADseq was used to identify 8,010 unlinked SNP markers from the nuclear genome of 156 individuals. Data relating to population structure support the hypothesis that the Rio Negro acted as a significant genetic barrier for A. longifolia. On the other hand, no genetic differentiation was detected among populations spanning the narrower Rio Branco, which is a tributary of the Rio Negro. This study shows that the strength of riverine barriers for Amazon plants is dependent on the width of the river separating populations and species‐specific dispersal traits. Future studies of plants with contrasting life history traits will further improve our understanding of the landscape genetics and allopatric speciation history of Amazon plant diversity.
Tolerance or avoidance: drought frequency determines the response of an N2‐fixing tree
Authors: Minucci Jeffrey M. , Miniat Chelcy Ford , Teskey Robert O. , Wurzburger Nina
Published: April 2017

Climate change is increasing drought frequency, which may affect symbiotic N2 fixation (SNF), a process that facilitates ecosystem recovery from disturbance. Here, we assessed the effect of drought frequency on the ecophysiology and SNF rate of a common N2‐fixing tree in eastern US forests.

We grew Robinia pseudoacacia seedlings under the same mean soil moisture, but with different drought frequency caused by wet–dry cycles of varying periodicity.

We found no effect of drought frequency on final biomass or mean SNF rate. However, seedlings responded differently to wet and dry phases depending on drought frequency. Under low‐frequency droughts, plants fixed carbon (C) and nitrogen (N) at similar rates during wet and dry phases. Conversely, under high‐frequency droughts, plants fixed C and N at low rates during dry phases and at high rates during wet phases.

Our findings suggest that R. pseudoacacia growth is resistant to increased drought frequency because it employs two strategies – drought tolerance or drought avoidance, followed by compensation. SNF may play a role in both by supplying N to leaf tissues for acclimation and by facilitating compensatory growth following drought. Our findings point to SNF as a mechanism for plants and ecosystems to cope with drought.
Quantile Aggregation of Density Forecasts
Authors: Busetti Fabio
Published: April 2017

Quantile aggregation (or ‘Vincentization’) is a simple and intuitive way of combining probability distributions, originally proposed by S.B. Vincent in 1912. In certain cases, such as under Gaussianity, the Vincentized distribution belongs to the same family as that of the individual distributions and it can be obtained by averaging the individual parameters. This article compares the properties of quantile aggregation with those of the forecast combination schemes normally adopted in the econometric forecasting literature, based on linear or logarithmic averages of the individual densities. Analytical results and Monte Carlo experiments indicate that the properties of quantile aggregation are between those of the linear and the logarithmic pool. Larger differences among the combination schemes occur when there are biases in the individual forecasts: in that case quantile aggregation seems preferable on the whole. The practical usefulness of Vincentization is illustrated empirically in the context of linear forecasting models for Italian GDP and quantile predictions of euro area inflation.
Comparison of reproductive investment in native and non‐native populations of common wall lizards reveals sex differences in adaptive potential
Authors: MacGregor Hannah E. A. , While Geoffrey M. , Uller Tobias
Published: April 2017

Non‐native animals can encounter very different environments than those they are adapted to. Functional changes in morphology, physiology and life‐history following introduction show that organisms can adapt both fast and efficiently. It remains unclear, however, if female reproductive characters and male sexually selected behaviour show the same adaptive potential. Furthermore, the invasion success and evolutionary trajectory of non‐native species might often depend on the ability of the sexes to coordinate shifts in characters associated with reproductive strategy. The common wall lizard, Podarcis muralis, has been repeatedly introduced from southern Europe to England over the past 80 years. Lizards in England experience a cool, seasonal climate that effectively restricts recruitment to the first clutch of the season, whereas in their native range up to three clutches per season recruit. As a consequence, both females and males in non‐native populations should benefit from reducing or even eliminating their reproductive investment in second clutches. Using a combination of field data and experiments, we show that non‐native females produce relatively larger and heavier first seasonal clutches and smaller and lighter second seasonal clutches compared to native females. In contrast, non‐native and native males do not differ in their territorial and sexual behaviour later in the season. An adaptive shift in male seasonal reproductive investment may be constrained because males use breeding females as cues for sexual behaviour. If this is so, we expect a general pattern across climatic regimes whereby female reproductive investment evolves first, with responses in males lagging behind.
China, An Upstream Hegemon: A Destabilizer for the Governance of the Mekong River?
Authors: Han Heejin
Published: April 2017

Transboundary rivers have remained one of the sources of contention and cooperation among states in international politics. The Mekong is one such river along which China and five Southeast Asian countries have organized their political, economic, and social lives. Studies examining the water politics of this river have argued that the lack of a comprehensive institution to govern this regional common pool resource and the growing power asymmetry between China, an upstream riparian state, and its Southeast Asian neighbors dampen the prospect for an effective governance of the river. Particularly, the economic rise of China and its concomitant increase in demand for energy and water resources has raised concerns about the negative impacts that this would have on the downstream countries. Examination of recent developments regarding the Mekong River suggests, however, that China has adopted a more collaborative approach by engaging in joint development projects and exchanging information and technology via existing sub‐regional and regional multilateral bodies since the early 2000s. The study concludes that this growing evidence of cooperation should be taken into consideration for a more comprehensive understanding of China's policy towards the Mekong River.
The Offensive Realists Are Not Wrong: China's Growth and Aggression, 1976–2001
Authors: Jung Sung Chul , Lee Kihyun
Published: April 2017

Is China's rise a threat? Offensive realists see rising China as a main cause of global instability in the 21st century. Because all states seek security through power maximization, China will clash with the United States for regional hegemony in Asia. But critics of the offensive realist view emphasize common interests, global institutions, and domestic constraints, particularly since China's rapid growth makes the country more open to and dependent on the global economy. This study compares these competing approaches to China's growth and regional stability and develops hypotheses based on four factors that could influence China's interaction with other nations: China's own level of economic power, its growth rate, whether a potential antagonist is allied with the United States, and whether the two countries have a territorial dispute. Then it conducts a logit analysis of China's military aggression against Asian states and major powers in the post‐Mao period. The results show that China's growing power has encouraged its initiation of military conflicts, and that Beijing has become aggressive against its opponents in territorial disputes, but not more so against America's Asian allies than against other countries. The findings suggest that China's continued rise will likely contribute to its firm position in the South and East China Seas and its resolute protection of core strategic and economic interests.
The transition time from the juvenile phase to the adult phase differs in soybean cultivars ‘Enrei’ and ‘Peking’
Authors: Ozawa Suguru , Hatakeyama Katsunori , Takahata Yoshihito , Yokoi Shuji
Published: April 2017

Plants develop juvenile phase to adult phase in vegetative stage. Although soybean is a very important crop worldwide, there has been only one study of the juvenile–adult phase change. In this study, we determined that the juvenile–adult phase change occurred at different stages in two soybean cultivars that differ in their photosensitivity. Cultivar ‘Enrei’ (E1e2e3E4) is weakly photosensitive and cultivar ‘Peking’ (E1E2E3E4) is strongly photosensitive. In ‘Enrei’, the leaf size gradually increased at a constant leaf position regardless of the difference in day length. In ‘Peking’ plants transferred to short‐day conditions at several leaf development stages, leaf size gradually increased at different leaf positions. Expression of miR156 by ‘Enrei’ transferred to short‐day conditions had nearly the same pattern as that of ‘Enrei’ grown under long‐day conditions. In ‘Peking’, the expression of miR156 had different patterns in younger leaves of plants subjected to either a short‐day treatment or long‐day conditions. These results indicate that the E2 and E3 loci that regulate photosensitivity also regulate the expression of miR156 and the juvenile–adult phase change in soybean.
Contracting Models for P2P Content Distribution
Authors: Ghasemkhani Hossein , Li Yung‐Ming , Moinzadeh Kamran , Tan Yong
Published: April 2017

In recent years, peer‐to‐peer (P2P) networks have become an increasingly popular method for distributing digital content. In this study, we consider the development of optimal contracts for a P2P network by a profit‐seeking provider to support the operations of an online file exchange service. By utilizing the principal‐agent model of incentive theory, we propose appropriate reward and pricing schemes for profit‐seeking P2P content distribution networks. We show that when peers are homogeneous, upload compensation increases with propagation delay uncertainty, maximum uploading nodes allowed, peers' provision cost and disutility of download delay, but decreases with the network size and content availability. We also characterize a general contracting model where there are a countable number of peer classes which are heterogeneous in their provisioning costs. For the case of two peer classes where optimal delays are separable, we derive the optimal upload compensations under different scenarios and show that the impact of operational parameters is quite similar to the case of homogeneous peers, lending support to the robustness of our analysis.
Nitrate enhancement of CAM activity in two Kalanchoë species is associated with increased vacuolar proton transport capacity
Authors: Pereira Paula Natália , Smith James Andrew Charles , Mercier Helenice
Published: April 2017

Among species that perform CAM photosynthesis, members of the genus Kalanchoë have been studied frequently to investigate the effect of environmental factors on the magnitude of CAM activity. In particular, different nitrogen sources have been shown to influence the rate of nocturnal CO2 fixation and organic‐acid accumulation in several species of Kalanchoë. However, there has been little investigation of the interrelationship between nitrogen source (nitrate versus ammonium), concentration and the activity of the vacuolar proton pumps responsible for driving nocturnal organic‐acid accumulation in these species. In the present study with Kalanchoë laxiflora and Kalanchoë delagoensis cultivated on different nitrogen sources, both species were found to show highest total nocturnal organic‐acid accumulation and highest rates of ATP‐ and PPi‐dependent vacuolar proton transport on 2.5 mM nitrate, whereas plants cultivated on 5.0 mM ammonium showed the lowest values. In both species malate was the principal organic‐acid accumulated during the night, but the second‐most accumulated organic‐acid was fumarate for K. laxiflora and citrate for K. delagoensis. Higher ATP‐ and PPi‐dependent vacuolar proton transport rates and greater nocturnal acid accumulation were observed in K. delagoensis compared with K. laxiflora. These results show that the effect of nitrogen source on CAM activity in Kalanchoë species is reflected in corresponding differences in activity of the tonoplast proton pumps responsible for driving sequestration of these acids in the vacuole of CAM‐performing cells.
HLAMatchmaker is effective for selecting appropriate platelet units for alloimmunised thrombocytopaenic patients who are refractory to random donor platelets
Authors: O'Rafferty C. , Rooney G. , Hagan R. , Woolfson M. , O'Donghaile D. , Fitzgerald J.
Published: April 2017

Background

HLAMatchmaker has been used in the Irish Blood Transfusion Service (IBTS) to select platelets for HLA‐alloimmunised, platelet refractory thrombocytopaenic patients since 2006. Although available since 2002, only three studies have been published supporting the programme's effectiveness for this indication.

Objectives

We sought to examine increments to HLA‐matched platelets (HMPs) at various matchmaker scores and to examine the impact of transfusing older platelets and ABO‐mismatched platelets to this patient group.

Methods/Materials

A total of 20 consecutive HLA‐alloimmunised thrombocytopaenic patients were retrospectively studied. Data collected included: pre‐ and post‐transfusion platelet count, indication for transfusion, HLAMatchmaker score, age of unit and degree of ABO mismatch. Data were also collected on the last 3 U of (RDPs). The Mann–Whitney U‐test was used to compare increments between transfusion episodes of random donor platelets (RDPs) vs HMPs with matchmaker scores <3, 4–7 or >8.

Results

Increments at <2 h were available for 63 transfusion episodes. Increments at 2–24 h were available for 93 transfusion episodes. Increments were higher when transfusing HMPs than when transfusing RDPs. Increments for HMPs that were ABO mismatched were no different than for ABO‐identical units, with the exception of late increments post‐transfusing HMPs with a major ABO mismatch. Age of platelets did not influence increments.

Conclusion

The use of HLAMatchmaker to select platelet units for thrombocytopaenic HLA‐alloimmunised patients produced satisfactory platelet increments. When providing HLAMatchmaker‐selected HMPs, ABO mismatch and the use of platelet units that are up to 7 days old should be permissible.