Ant genomics (Hymenoptera: Formicidae): challenges to overcome and opportunities to seize

SN is funded by the Danish National Research Foundation (DNRF57). YW is funded by BBSRC grant BB/K004204/1, NERC grant NE/L00626X/1, and is a fellow of the Software Sustainability Institute

Elliptic flow contribution to two-particle correlations at different orientations to the reaction plane

Collective anisotropic particle flow, a general phenomenon present in relativistic heavy-ion collisions, can be separated from direct particle-particle correlations of different physics origin by virtue of its specific azimuthal pattern. We provide expressions for flow-induced two-particle azimuthal correlations, if one of the particles is detected under fixed directions with respect to the reaction plane. We consider an ideal case when the reaction plane angle is exactly known, as well as present the general expressions in case of finite event-plane resolution. We foresee applications for the study of generic two-particle correlations at large transverse momentum originating from jet fragmentation.Comment: 5 pages, 3 figures, to be published as Rapid Communications in Phys.Rev.C Re-submit paper to with small improvements in text for better understanding, some minor changes in notation, and correcting one formula where a summation was forgotten. One new reference, one reference to conference report removed since full paper was already reference

Stabilization of Inverse Miniemulsions by Silyl-Protected Homopolymers

Inverse (water-in-oil) miniemulsions are an important method to encapsulate hydrophilic payloads such as oligonucleotides or peptides. However, the stabilization of inverse miniemulsions usually requires block copolymers that are difficult to synthesize and/or cannot be easily removed after transfer from a hydrophobic continuous phase to an aqueous continuous phase. We describe here a new strategy for the synthesis of a surfactant for inverse miniemulsions by radical addition–fragmentation chain transfer (RAFT) polymerization, which consists in a homopolymer with triisopropylsilyl protecting groups. The protecting groups ensure the efficient stabilization of the inverse (water-in-oil, w/o) miniemulsions. Nanocapsules can be formed and the protecting group can be subsequently cleaved for the re-dispersion of nanocapsules in an aqueous medium with a minimal amount of additional surfactant

Acacia holosericea (Fabaceae) litter has allelopathic and physical effects on mission grass (Cenchrus pedicellatus and C. polystachios) (Poaceae) seedling establishment

Invasion of grass weeds is a major threat for ecosystems. Mission grass (Cenchrus pedicellatus and C. polystachios) vigorously competes with native vegetation and has become a serious problem in northern Australian savanna. A lower density of mission grass has been observed under the canopy of stands of native Acacia holosericea. We used a series of laboratory and shade house experiments to assess the potential for allelopathy and the role of litter on germination, emergence and seedling growth of these two species of mission grass. Different concentrations of aqueous leaf extract of A. holosericea were used to assess allelopathic effects on germination. Various depths and types of litter were used to investigate the allelopathic and physical effects of litter on emergence and growth of mission grass seedlings in the shade house. Results indicate that extracts did not affect germination of either species of mission grass but root growth of seedlings was affected. Emergence of seedlings in the shade house was affected by physical litter treatments but not by allelopathy. After emergence no negative effects on seedling growth were detected. Overall we found that there was no allelopathic effect on germination and that the negative effect on emergence was due to the physical properties of the litter. This effect on emergence increased with increasing depth of litter. Allelopathy slightly inhibited root growth but once seedlings emerged, litter tended to facilitate growth. This has implications for the ecological management of mission grass on disturbed lands, using strategies such as manipulation of litter cover through Acacia establishment

Impurity and edge roughness scattering in armchair graphene nanoribbons: Boltzmann approach

The conductivity of armchair graphene nanoribbons in the presence of short-range impurities and edge roughness is studied theoretically using the Boltzmann transport equation for quasi-one-dimensional systems. As the number of occupied subbands increases, the conductivity due to short-range impurities converges towards the two-dimensional case. Calculations of the magnetoconductivity confirm the edge-roughness-induced dips at cyclotron radii close to the ribbon width suggested by the recent quantum simulations

Interfaces Within Graphene Nanoribbons

We study the conductance through two types of graphene nanostructures: nanoribbon junctions in which the width changes from wide to narrow, and curved nanoribbons. In the wide-narrow structures, substantial reflection occurs from the wide-narrow interface, in contrast to the behavior of the much studied electron gas waveguides. In the curved nanoribbons, the conductance is very sensitive to details such as whether regions of a semiconducting armchair nanoribbon are included in the curved structure -- such regions strongly suppress the conductance. Surprisingly, this suppression is not due to the band gap of the semiconducting nanoribbon, but is linked to the valley degree of freedom. Though we study these effects in the simplest contexts, they can be expected to occur for more complicated structures, and we show results for rings as well. We conclude that experience from electron gas waveguides does not carry over to graphene nanostructures. The interior interfaces causing extra scattering result from the extra effective degrees of freedom of the graphene structure, namely the valley and sublattice pseudospins.Comment: 19 pages, published version, several references added, small changes to conclusion

Климатические особенности и статистические оценки изменения элементов климата в районах вечной мерзлоты на территории севера Западной Сибири

Актуальность работы связана с необходимостью оценки изменений климата, влияющих на многолетнюю мерзлоту, в связи с возможным увеличением выбросов парниковых газов и увеличения аварийности на объектах промышленной, в том числе и нефтегазовой, инфраструктуры при таянии многолетнемерзлых пород. Цель работы: исследование современных изменений характеристик климата, непосредственно влияющих на термическое состояние почвогрунтов в районах распространения многолетней мерзлоты севера Западной Сибири. Методы исследования. Анализ многолетних изменений метеорологических данных включал в себя проверку нулевых гипотез о случайности и однородности рядов наблюдений и наличия тренда. Проверка на однородность осуществлялась с помощью теста Аббе, на случайность - критерием Питмена, на наличие тренда производилась с помощью критерия инверсий. Вывод о неслучайном изменении или нарушении однородности рядов соответствовал условию, когда расчетная статистика превышала соответствующее критическое значение при уровне значимости 0,05. Результаты. Рассмотрены особенности климата севера Западной Сибири и его изменчивость в последние годы. Исследованы изменения температуры воздуха и почвогрунтов на глубинах 160 и 320 см, продолжительность прямой солнечной радиации, суммы атмосферных осадков и высоты снежного покрова на основе инструментальных данных за последние 35 лет. В результате статистического анализа установлено сохранение темпов роста температуры воздуха в теплое время года, увеличение температуры почвогрунтов в течение всего года, выявлен зональный характер изменения суммы атмосферных осадков и снежного покрова. Микроклиматические изменения характеристик метеорологических величин могут искажать реальную картину изменения климата.The relevance of the research is related to the necessity to assess climate changes affecting the permafrost due to the possible growth of greenhouse gas emissions and increase of accident rate in industrial, oil and gas infrastructure at permafrost thawing. The aim of the research is to estimate the current changes in climate characteristics, which affect directly the thermal state of soils in permafrost areas in the north of Western Siberia. Methods. Analysis of long-term changes of meteorological data consisted of tests of null hypothesis of randomness and homogeneity of observation series and trend presence. The homogeneity test was carried out using the Abbe test, the test of randomness was carried out by Pitman criterion, the trend presence was checked using the criterion of inversions. The conclusion on nonrandom change or violation of the homogeneity of rows corresponded to the condition, when the modulus of the estimated statistics exceeded the corresponding critical value at significance level of 0,05. Results. The paper considers the climatic features in the north of Western Siberia and its variability in recent years. The analysis of temperature changes of air and soil at depths of 160 and 320 cm, the amount of precipitation and snow cover based on the instrumental data for the last 35 years has shown that air temperature continues rising in the warmer months, soil temperature increases throughout the year. The authors have revealed zonal character of changes in the amount of precipitation and snow cover. Microclimatic changes in characteristic of meteorological values can distort the real picture of climate change

Suspension-adapted Chinese hamster ovary-derived cells expressing green fluorescent protein as a screening tool for biomaterials

Synthetic biomaterials play an important role in regenerative medicine. To be effective they must support cell attachment and proliferation in addition to being non-toxic and non-immunogenic. We used a suspension-adapted Chinese hamster ovary-derived cell line expressing green fluorescent protein (GFP) to assess cell attachment and growth on synthetic biomaterials by direct measurement of GFP-specific fluorescence. To simplify operations, all cell cultivation steps were performed in orbitally-shaken, disposable containers. Comparative studies between this GFP assay and previously established cell quantification assays demonstrated that this novel approach is suitable for rapid screening of a large number of samples. Furthermore the utility of our assay system was confirmed by evaluation of cell growth on three polyvinylidene fluoride polymer scaffolds that differed in pore diameter and drawing conditions. The data presented here prove the general utility of GFP-expressing cell lines and orbital shaking technology for the screening of biomaterials for tissue engineering application

Vitellogenin Underwent Subfunctionalization to Acquire Caste and Behavioral Specific Expression in the Harvester Ant Pogonomyrmex barbatus

PMCID: PMC3744404This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication

Retroviral Gene Therapy: May The Fibronectin Be With You

poster abstractReplication incompetent retroviral vectors are currently used in phase 1 clinical trials for genetic therapy of disorders of the blood and the immune system, as vector integration into the genome of target stem cells provides stable long-term expression of the therapeutic transgene. We have previously shown that co-localization of the viral particles and the target cells on the recombinant fibronectin fragment CH-296 enhances the retroviral gene transfer efficiency into primitive hematopoietic cells including stem cells. Here, we report additional technical details for improving the gene transfer efficiencies into hematopoietic cell lines, primary human T-cells and CD34+ cells and demonstrate that CH-296 can be used at least three times without any loss of efficiency. Finally, we expand the range of viral proteins known to directly bind to fibronectin CH-296 to the commonly used VSV-G, GaLV and foamyviral (FV) envelope