bluuebunny/crossref_metadata_2025 huggingface dataset:
Communication: Coordination structure of bromide ions associated with hexyltrimethylammonium cations at liquid/liquid interfaces under potentiostatic control as studied by total-reflection X-ray absorption fine structure
Authors: Nagatani Hirohisa , Harada Makoto , Tanida Hajime , Sakae Hiroki , Imura Hisanori
Published: March 2014

Total-reflection X-ray absorption fine structure (TR-XAFS) technique was applied for the first time to an interface between two immiscible electrolyte solutions under potentiostatic control. The hydration structure of bromide ions was investigated at polarized 2-octanone/water interfaces. TR-XAFS spectra at Br K-edge measured in the presence of hexyltrimethylammonium bromide (C6TAB) were slightly modified depending on the Galvani potential difference (${\rm \Delta }_{\rm o}^{\rm w} \phi$Δowϕ). The extended X-ray absorption fine structure analysis exposed hydration structure changes of bromide ions at the polarized interface. The coordination structure of bromide ions at the interface could be analyzed as compared with bromide ions dissolved in aqueous solution and Br−-exchanged resin having quaternary ammonium groups. The results indicated that bromide ions were associated with C6TA+ at the polarized interface. The relative contribution of ion association form of bromide ions with quaternary ammonium groups was enhanced at a potential close to the ion transfer of C6TA+, where the interfacial concentration of C6TA+ is increased as a function of ${\rm \Delta }_{\rm o}^{\rm w} \phi$Δowϕ.
Magnetic properties of perpendicular exchange coupled composite with a synthesis antiferromagnetic sandwich structure
Authors: Chu H. G. , Guo H. H. , Xie H. L. , Ma B. , Zhang Z. Z. , Wang Y. , Jin Q. Y.
Published: March 2014

In this study, an exchange coupled composite (ECC) film with an antiferromagnetic sandwich structure L10-FePt/[Co/Ni]5/Ru/[Co/Ni]10 (FePt-CN-Ru) is prepared via dc magnetron sputtering and measured by vibrating sample magnetometer. The results show that FePt-CN-Ru film exhibits ECC characteristics, with excellent angular tolerance, low remanance magnetization, and a narrow switching field. Its thermal stability is higher than that of conventional ECC film. Finally, magnetization reversal is demonstrated through micromagnetic simulation.
Excitonic effects of E11, E22, and E33 in armchair-edged graphene nanoribbons
Authors: Lu Yan , Zhao Shangqian , Lu Wengang , Liu Hong , Liang Wenjie
Published: March 2014

We explore excitonic effects of E11, E22, and E33, which are excitons formed between the three highest valence subbands and the three lowest conduction ones, in armchair-edged graphene nanoribbons by applying the extended tight-binding model including electron-electron interactions. Our results show that the excitation energies and the binding energies decrease inversely with the ribbon widths and can be classified into three categories based on their width indices. We found the relation between the band structures and the binding energies and explained some recent observations of strong excitonic effects in graphene.
The chirp-control of frequency-tunable narrowband terahertz pulses by nonlinearly chirped laser pulse beating
Authors: Kamada Shohei , Yoshida Tetsuya , Aoki Takao
Published: March 2014

We demonstrate a method for controlling the chirp of the frequency-tunable narrowband terahertz pulses that are generated by photomixing with nonlinearly chirped laser pulse pairs. We find that in a grating-based laser-pulse stretcher, the frequency sweep rates of the generated terahertz pulses can be controlled by simply changing the incident angle. This method is also applicable to other mechanisms of terahertz pulse generation.
Effect of compression ratio on compression ignition engine performance with biodiesel and producer gas in mixed fuel mode
Authors: Balakrishnan N. , Mayilsamy K.
Published: March 2014

Energy recovery from waste biomasses has become the most important solution, in addition to find suitable alternative fuel rather than the usual mineral fuel. In this study used vegetable oil biodiesel has been used as an injected fuel and waste wood chips as an inducted fuel to generate producer gas in a modified double walled fixed bed downdraft gasifier, and to study the fuel's performance in an Internal Combustion Engine. The effect of compression ratio on the engine performance is critically examined with different load while the fuel injection pressure and fuel injection timing has been kept constant throughout the run. The result shows that the brake thermal efficiency gradually increases with increase in compression ratio with simultaneous decrease in brake specific energy consumption; also the remarkable emission reduction ensures the suitability of mixed fuel at higher possible compression ratio without any modifications in the engine. It is concluded that the ignition delay, noise pollution, and engine vibration limit the compression ratio to 18 as a maximum.
Cobalt intercalation at the graphene/iridium(111) interface: Influence of rotational domains, wrinkles, and atomic steps
Authors: Vlaic S. , Kimouche A. , Coraux J. , Santos B. , Locatelli A. , Rougemaille N.
Published: March 2014

Using low-energy electron microscopy, we study Co intercalation under graphene grown on Ir(111). Depending on the rotational domain of graphene on which it is deposited, Co is found intercalated at different locations. While intercalated Co is observed preferentially at the substrate step edges below certain rotational domains, it is mostly found close to wrinkles below other domains. These results indicate that curved regions (near substrate atomic steps and wrinkles) of the graphene sheet facilitate Co intercalation and suggest that the strength of the graphene/Ir interaction determines which pathway is energetically more favorable.
Graphene cardboard: From ripples to tunable metamaterial
Authors: Koskinen Pekka
Published: March 2014

Recently, graphene was introduced with tunable ripple texturing, a nanofabric enabled by graphene's remarkable elastic properties. However, one can further envision sandwiching the ripples, thus constructing composite nanomaterial, graphene cardboard. Here, the basic mechanical properties of such structures are investigated computationally. It turns out that graphene cardboard is highly tunable material, for its elastic figures of merit vary orders of magnitude, with Poisson ratio tunable from 10 to −0.5 as one example. These trends set a foundation to guide the design and usage of metamaterials made of rippled van der Waals solids.
Multi-band localized spoof plasmons with texturing closed surfaces
Authors: Li Zhuo , Liu Liangliang , Gu Changqing , Ning Pingping , Xu Bingzheng , Niu Zhenyi , Zhao Yongjiu
Published: March 2014

We demonstrate that periodically textured closed surface with multiple groove depths can support multi-band spoof localized surface plasmons (LSPs). It is interesting to note that the spoof LSPs in each band resemble those generated by the textured closed surface of the same periodicity with the corresponding single groove depth. In this way, it paves the way for the generation and design of multi-band spoof LSPs. Moreover, multiple resonance band structures and devices, such as resonator, oscillator, and other band-notched structures in the microwave and terahertz regimes can be realized.
Regulation of post-mortem glycolysis in ruminant muscle
Authors: Ferguson D. M. , Gerrard D. E.
Published: March 2014

As a tissue, muscle has the unique ability to switch its metabolic source of ATP, the energy currency underpinning muscle function. During oxygen debt, such as that occurring immediately following the death of animals, anaerobic metabolism is initiated in an attempt to restore homeostasis within the muscle. The cascade of biochemical events that are initiated is paramount in the context of meat quality. This review revisits this reasonably well-known subject but takes a new perspective by drawing on the understanding outside the traditional discipline of meat science. Our understanding of the intrinsic regulators of glycolytic flux has improved but knowledge gaps remain. Further efforts to understand how the glycolytic enzyme kinetics are influenced by both pre- and post-slaughter factors will be beneficial in the ongoing quest to maximise fresh meat quality.
In a long-term experimental demography study, excluding ungulates reversed invader's explosive population growth rate and restored natives
Authors: Kalisz Susan , Spigler Rachel B. , Horvitz Carol C.
Published: March 2014

Significance

In ecosystems worldwide, the presence of overabundant ungulates (e.g. deer, cows) and the invasion of exotic plants are disrupting native communities. A recent hypothesis causally links these problems implicating overabundant ungulates in enhancing invaders’ demographic success. We tested this hypothesis in a forest where white-tailed deer are overabundant and garlic mustard is aggressively invading. Using long-term, replicated deer exclusion/deer access plot pairs, we quantified population density, growth, and decline of this invader and native plants. We conclusively demonstrate that deer are required for garlic mustard success; its local extinction is projected where deer are absent. Our findings provide the first definitive support connecting overabundant ungulates to enhanced invader success, with broad implications for biodiversity and ecosystem function.
CD31 is a key coinhibitory receptor in the development of immunogenic dendritic cells
Authors: Clement Marc , Fornasa Giulia , Guedj Kevin , Ben Mkaddem Sanae , Gaston Anh-Thu , Khallou-Laschet Jamila , Morvan Marion , Nicoletti Antonino , Caligiuri Giuseppina
Published: March 2014

Significance

Much is known about the costimulatory receptors that contribute to the full maturation of DCs, whereas the coinhibitory receptors that are involved in the control of DC maturation and the maintenance of peripheral tolerance remain largely unknown. This work reveals that CD31, a transhomophilic coreceptor constitutively expressed by resting DCs, has a key coinhibitory function. CD31 is lost by maturing DCs, and the absence of CD31 favors immunogenic maturation. In contrast, upholding CD31 signaling during maturation converts stimulated DCs into tolerogenic cells. These findings will likely have a substantial impact on immunology research, because knowledge of the immune modulation of DCs is important in immune homeostasis as well as in communicable and noncommunicable diseases, including infection, autoimmunity, and cancer.
Direct evidence for positive selection of skin, hair, and eye pigmentation in Europeans during the last 5,000 y
Authors: Wilde Sandra , Timpson Adrian , Kirsanow Karola , Kaiser Elke , Kayser Manfred , Unterländer Martina , Hollfelder Nina , Potekhina Inna D. , Schier Wolfram , Thomas Mark G. , Burger Joachim
Published: March 2014

Significance

Eye, hair, and skin pigmentation are highly variable in humans, particularly in western Eurasian populations. This diversity may be explained by population history, the relaxation of selection pressures, or positive selection. To investigate whether positive natural selection is responsible for depigmentation within Europe, we estimated the strength of selection acting on three genes known to have significant effects on human pigmentation. In a direct approach, these estimates were made using ancient DNA from prehistoric Europeans and computer simulations. This allowed us to determine selection coefficients for a precisely bounded period in the deep past. Our results indicate that strong selection has been operating on pigmentation-related genes within western Eurasia for the past 5,000 y.
Photic memory for executive brain responses
Authors: Chellappa Sarah Laxhmi , Ly Julien Q. M. , Meyer Christelle , Balteau Evelyne , Degueldre Christian , Luxen André , Phillips Christophe , Cooper Howard M. , Vandewalle Gilles
Published: March 2014

Significance

Light is a powerful stimulant for human alertness and cognition that can be easily administered to improve performance or counteract the negative impact of sleepiness, even during the day. Here, we show that prior exposure to longer wavelength light (orange), relative to shorter wavelength (blue), enhances the subsequent impact of light on executive brain responses. These findings emphasize the importance of light for human cognitive brain function and constitute compelling evidence in favor of a cognitive role for melanopsin. This recently discovered photopigment may therefore provide a unique form of “photic memory” for human cognition and play a broader role than previously apprehended. Ultimately, these findings support the idea that the integration of light exposure over long periods of time can help optimize cognitive brain function.
Complete replication of hepatitis B virus and hepatitis C virus in a newly developed hepatoma cell line
Authors: Yang Darong , Zuo Chaohui , Wang Xiaohong , Meng Xianghe , Xue Binbin , Liu Nianli , Yu Rong , Qin Yuwen , Gao Yimin , Wang Qiuping , Hu Jun , Wang Ling , Zhou Zebin , Liu Bing , Tan Deming , Guan Yang , Zhu Haizhen
Published: March 2014

Significance

More than 500 million people are persistently infected with hepatitis B virus (HBV) and/or hepatitis C virus (HCV) and are at a risk of developing chronic hepatitis, cirrhosis, and liver cancer. The absence of robust cell culture systems for both viral infections limits the understanding of the virus lifecycle and pathogenesis required for the development of vaccine and antivirals. We have established a novel human hepatoma cell line termed “HLCZ01” that supports the entire lifecycle of both HBV and HCV produced both in cell culture and clinically. This cell line provides a powerful tool for addressing the virus lifecycle and the development of antivirals and vaccines.
Geothermal activity helps life survive glacial cycles
Authors: Fraser Ceridwen I. , Terauds Aleks , Smellie John , Convey Peter , Chown Steven L.
Published: March 2014

Significance

The evolution and maintenance of diversity through cycles of past climate change have hinged largely on the availability of refugia. Geothermal refugia may have been particularly important for survival through past glaciations. Our spatial modeling of Antarctic biodiversity indicates that some terrestrial groups likely survived throughout intense glacial cycles on ice-free land or in sub-ice caves associated with areas of geothermal activity, from which recolonization of the rest of the continent took place. These results provide unexpected insights into the responses of various species to past climate change and the importance of geothermal regions in promoting biodiversity. Furthermore, they indicate the likely locations of biodiversity “hotspots” in Antarctica, suggesting a critical focus for future conservation efforts.
Elephants can determine ethnicity, gender, and age from acoustic cues in human voices
Authors: McComb Karen , Shannon Graeme , Sayialel Katito N. , Moss Cynthia
Published: March 2014

Significance

Recognizing predators and judging the level of threat that they pose is a crucial skill for many wild animals. Human predators present a particularly interesting challenge, as different groups of humans can represent dramatically different levels of danger to animals living around them. We used playbacks of human voice stimuli to show that elephants can make subtle distinctions between language and voice characteristics to correctly identify the most threatening individuals on the basis of their ethnicity, gender, and age. Our study provides the first detailed assessment of human voice discrimination in a wild population of large-brained, long-lived mammals, and highlights the potential benefits of sophisticated mechanisms for distinguishing different subcategories within a single predator species.
Structural dynamics of troponin during activation of skeletal muscle
Authors: Fusi Luca , Brunello Elisabetta , Sevrieva Ivanka R. , Sun Yin-Biao , Irving Malcolm
Published: March 2014

Significance

Muscle contraction is controlled by structural changes in the thin filament of the muscle sarcomere triggered by calcium binding to troponin. It has long been suspected that myosin binding has an additional effect in switching on the thin filament, but the biological function of this effect was unknown. We have elucidated the in situ sequence of calcium-induced structural changes of troponin and identified a kinetic component tracking myosin binding to the thin filament. We propose a model of muscle regulation with kinetics determined by coordinated changes in the structures of both thick and thin filaments in response to mechanical conditions rather than, as in the conventional view, solely by the calcium transient and structural changes in the thin filament.
Partial loss of TDP-43 function causes phenotypes of amyotrophic lateral sclerosis
Authors: Yang Chunxing , Wang Hongyan , Qiao Tao , Yang Bin , Aliaga Leonardo , Qiu Linghua , Tan Weijia , Salameh Johnny , McKenna-Yasek Diane M. , Smith Thomas , Peng Lingtao , Moore Melissa J. , Brown Robert H. , Cai Huaibin , Xu Zuoshang
Published: March 2014

Significance

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease that causes paralysis and death. TDP-43 is a protein that regulates gene expression. TDP-43 aggregation and depletion from cell nucleus are found in ALS. Therefore, TDP-43 may cause neurodegeneration by generating toxicity from its aggregation or by a loss of its function. Our experiments test the consequence of a partial loss of TDP-43 function in mice. The results demonstrate that a partial loss of TDP-43 function is sufficient to cause neurodegeneration and ALS symptoms. In addition, we have found evidence for TDP-43 dysfunction in human ALS. Therefore, we propose that TDP-43 dysfunction causes neurodegeneration in the human disease, and future therapy should aim to restore the normal function of TDP-43.
Diversity and evolution of secondary metabolism in the marine actinomycete genus
Salinispora
Authors: Ziemert Nadine , Lechner Anna , Wietz Matthias , Millán-Aguiñaga Natalie , Chavarria Krystle L. , Jensen Paul Robert
Published: March 2014

Significance

Microbial natural products are a major source of new drug leads, yet discovery efforts are constrained by the lack of information describing the diversity and distributions of the associated biosynthetic pathways among bacteria. Using the marine actinomycete genus
Salinispora
as a model, we analyzed genome sequence data from 75 closely related strains. The results provide evidence for high levels of pathway diversity, with most being acquired relatively recently in the evolution of the genus. The distributions and evolutionary histories of these pathways provide insight into the mechanisms that generate new chemical diversity and the strategies used by bacteria to maximize their population-level capacity to produce diverse secondary metabolites.
Charting Brachyury-mediated developmental pathways during early mouse embryogenesis
Authors: Lolas Macarena , Valenzuela Pablo D. T. , Tjian Robert , Liu Zhe
Published: March 2014

Significance

The gene-regulatory mechanisms for finely balanced cell-fate determination and morphogenesis during early animal development remain largely elusive. Here, we combine genomic, single-cell imaging and biochemical approaches to chart the molecular pathways mediated by a key developmental regulator—Brachyury. Our results shed light on mechanistic insights into the ultrafine organization of Brachyury-bound enhancers and link Brachyury function to cellular differentiation and housekeeping processes critical for coordinating early mouse embryogenesis.
Microvesicles containing miRNAs promote muscle cell death in cancer cachexia viaTLR7
Authors: He Wei A. , Calore Federica , Londhe Priya , Canella Alessandro , Guttridge Denis C. , Croce Carlo M.
Published: March 2014

Significance

MicroRNAs (miRNAs) are small, noncoding RNAs regulating gene expression. The aberrant expression of miRNAs is commonly associated with cancer. miRNAs can be packaged in exosomes/microvesicles secreted by the cells and involved in cell-to-cell signaling and communication; tumor-secreted miRNAs promote tumor spread and growth in the surrounding microenvironment. Apoptosis is reported to take place in wasting muscle in cancer cachexia, a debilitating syndrome associated with multiple types of cancer, although the mechanism remains elusive. This study shows that tumor-secreted microvesicles contain an elevated expression of miR-21 and induce myoblast apoptosis in cancer cachexia via a Toll-like receptor 7-c-Jun N-terminal kinase-dependent pathway.
EB1 enables spindle microtubules to regulate centromeric recruitment of Aurora B
Authors: Banerjee Budhaditya , Kestner Cortney A. , Stukenberg P. Todd
Published: March 2014

The Aurora B kinase coordinates kinetochore–microtubule attachments with spindle checkpoint signaling on each mitotic chromosome. We find that EB1, a microtubule plus end–tracking protein, is required to enrich Aurora B at inner centromeres in a microtubule-dependent manner. This regulates phosphorylation of both kinetochore and chromatin substrates. EB1 regulates the histone phosphorylation marks (histone H2A phospho-Thr120 and histone H3 phospho-Thr3) that localize Aurora B. The chromosomal passenger complex containing Aurora B can be found on a subset of spindle microtubules that exist near prometaphase kinetochores, known as preformed K-fibers (kinetochore fibers). Our data suggest that EB1 enables the spindle microtubules to regulate the phosphorylation of kinetochores through recruitment of the Aurora B kinase.
T cell–derived interleukin (IL)-21 promotes brain injury following stroke in mice
Authors: Clarkson Benjamin D.S. , Ling Changying , Shi Yejie , Harris Melissa G. , Rayasam Aditya , Sun Dandan , Salamat M. Shahriar , Kuchroo Vijay , Lambris John D. , Sandor Matyas , Fabry Zsuzsanna
Published: March 2014

T lymphocytes are key contributors to the acute phase of cerebral ischemia reperfusion injury, but the relevant T cell–derived mediators of tissue injury remain unknown. Using a mouse model of transient focal brain ischemia, we report that IL-21 is highly up-regulated in the injured mouse brain after cerebral ischemia. IL-21–deficient mice have smaller infarcts, improved neurological function, and reduced lymphocyte accumulation in the brain within 24 h of reperfusion. Intracellular cytokine staining and adoptive transfer experiments revealed that brain-infiltrating CD4+ T cells are the predominant IL-21 source. Mice treated with decoy IL-21 receptor Fc fusion protein are protected from reperfusion injury. In postmortem human brain tissue, IL-21 localized to perivascular CD4+ T cells in the area surrounding acute stroke lesions, suggesting that IL-21–mediated brain injury may be relevant to human stroke.
Einstein Hermitian metrics of positive sectional curvature
Authors: Koca Caner
Published: March 2014

It is shown that, up to scaling and isometry, the only complete 4-manifold with an Einstein metric of positive sectional curvature which is also Hermitian with respect to some complex structure is the complex projective plane

C
P

2

\mathbb {CP}_2

, equipped with its Fubini-Study metric.
Local bounded cochain projections
Authors: Falk Richard , Winther Ragnar
Published: March 2014

We construct projections from

H

Λ
k

(
Ω
)

H \Lambda ^k(\Omega )

, the space of differential

k
k

forms on

Ω
\Omega

which belong to

L
2

(
Ω
)

L^2(\Omega )

and whose exterior derivative also belongs to

L
2

(
Ω
)

L^2(\Omega )

, to finite dimensional subspaces of

H

Λ
k

(
Ω
)

H \Lambda ^k(\Omega )

consisting of piecewise polynomial differential forms defined on a simplicial mesh of

Ω
\Omega

. Thus, their definition requires less smoothness than assumed for the definition of the canonical interpolants based on the degrees of freedom. Moreover, these projections have the properties that they commute with the exterior derivative and are bounded in the

H

Λ
k

(
Ω
)

H \Lambda ^k(\Omega )

norm independent of the mesh size

h
h

. Unlike some other recent work in this direction, the projections are also locally defined in the sense that they are defined by local operators on overlapping macroelements, in the spirit of the Clément interpolant. A double complex structure is introduced as a key tool to carry out the construction.
Endobronchial Ultrasound–Transbronchial Needle Aspiration of Mediastinal and Hilar Lymphadenopathy Learning Curve
Authors: Kheir Fayez , Alokla Khalid , Myers Leann , Palomino Jaime
Published: March 2014

Endobronchial ultrasound (EBUS)-transbronchial needle aspiration (TBNA) has become a widely available tool that allows sampling of mediastinal and hilar lymph nodes with comparable accuracy as compared with the gold standard procedure, mediastinoscopy. The goal of this study was to evaluate the competence accuracy of this technique in academic medical center in patients with and without malignant disease. This was a retrospective chart review of the first 150 patients who underwent EBUS-TBNA at our institution with an operator not previously trained or supervised while performing the procedure. All nondiagnostic results were confirmed with mediastinoscopy. The cumulative sum analysis is a method used to continuously monitor performance against an established standard to attain competence in the procedure performed. Learning curve was assessed using cumulative sum method. Procedures were divided into sextiles (1–25, 26–50, 51–75, 76–100, 101–125, and 126–150). The technique's diagnostic accuracy was calculated for each of the 6 categories and trend toward improved accuracy was assessed using Cochran–Armitage trend test. Operator competency was achieved between 55th and 60th procedures. The diagnostic accuracy increased from 72% to 88% (from the first to third sextile) but remained stable afterwards at 88% (C-A trend test P = 0.091). The overall diagnostic accuracy was 84%. Trainees' learning rate varies while acquiring adequate knowledge. We suggest that a learning curve for each operator be used to assess competence in EBUS-TBNA procedure before physicians perform it without supervision.
Scaling laws of ambush predator ‘waiting’ behaviour are tuned to a common ecology
Authors: Wearmouth Victoria J. , McHugh Matthew J. , Humphries Nicolas E. , Naegelen Aurore , Ahmed Mohammed Z. , Southall Emily J. , Reynolds Andrew M. , Sims David W.
Published: March 2014

The decisions animals make about how long to wait between activities can determine the success of diverse behaviours such as foraging, group formation or risk avoidance. Remarkably, for diverse animal species, including humans, spontaneous patterns of waiting times show random ‘burstiness’ that appears scale-invariant across a broad set of scales. However, a general theory linking this phenomenon across the animal kingdom currently lacks an ecological basis. Here, we demonstrate from tracking the activities of 15 sympatric predator species (cephalopods, sharks, skates and teleosts) under natural and controlled conditions that bursty waiting times are an intrinsic spontaneous behaviour well approximated by heavy-tailed (power-law) models over data ranges up to four orders of magnitude. Scaling exponents quantifying ratios of frequent short to rare very long waits are species-specific, being determined by traits such as foraging mode (active versus ambush predation), body size and prey preference. A stochastic–deterministic decision model reproduced the empirical waiting time scaling and species-specific exponents, indicating that apparently complex scaling can emerge from simple decisions. Results indicate temporal power-law scaling is a behavioural ‘rule of thumb’ that is tuned to species’ ecological traits, implying a common pattern may have naturally evolved that optimizes move–wait decisions in less predictable natural environments.
Lethal control of an apex predator has unintended cascading effects on forest mammal assemblages
Authors: Colman N. J. , Gordon C. E. , Crowther M. S. , Letnic M.
Published: March 2014

Disruption to species-interaction networks caused by irruptions of herbivores and mesopredators following extirpation of apex predators is a global driver of ecosystem reorganization and biodiversity loss. Most studies of apex predators' ecological roles focus on effects arising from their interactions with herbivores or mesopredators in isolation, but rarely consider how the effects of herbivores and mesopredators interact. Here, we provide evidence that multiple cascade pathways induced by lethal control of an apex predator, the dingo, drive unintended shifts in forest ecosystem structure. We compared mammal assemblages and understorey structure at seven sites in southern Australia. Each site comprised an area where dingoes were poisoned and an area without control. The effects of dingo control on mammals scaled with body size. Activity of herbivorous macropods, arboreal mammals and a mesopredator, the red fox, were greater, but understorey vegetation sparser and abundances of small mammals lower, where dingoes were controlled. Structural equation modelling suggested that both predation by foxes and depletion of understorey vegetation by macropods were related to small mammal decline at poisoned sites. Our study suggests that apex predators’ suppressive effects on herbivores and mesopredators occur simultaneously and should be considered in tandem in order to appreciate the extent of apex predators’ indirect effects.
A Bayesian approach for inferring the dynamics of partially observed endemic infectious diseases from space-time-genetic data
Authors: Mollentze Nardus , Nel Louis H. , Townsend Sunny , le Roux Kevin , Hampson Katie , Haydon Daniel T. , Soubeyrand Samuel
Published: March 2014

We describe a statistical framework for reconstructing the sequence of transmission events between observed cases of an endemic infectious disease using genetic, temporal and spatial information. Previous approaches to reconstructing transmission trees have assumed all infections in the study area originated from a single introduction and that a large fraction of cases were observed. There are as yet no approaches appropriate for endemic situations in which a disease is already well established in a host population and in which there may be multiple origins of infection, or that can enumerate unobserved infections missing from the sample. Our proposed framework addresses these shortcomings, enabling reconstruction of partially observed transmission trees and estimating the number of cases missing from the sample. Analyses of simulated datasets show the method to be accurate in identifying direct transmissions, while introductions and transmissions via one or more unsampled intermediate cases could be identified at high to moderate levels of case detection. When applied to partial genome sequences of rabies virus sampled from an endemic region of South Africa, our method reveals several distinct transmission cycles with little contact between them, and direct transmission over long distances suggesting significant anthropogenic influence in the movement of infected dogs.
Why fruit rots: theoretical support for Janzen's theory of microbe–macrobe competition
Authors: Ruxton Graeme D. , Wilkinson David M. , Schaefer H. Martin , Sherratt Thomas N.
Published: March 2014

We present a formal model of Janzen's influential theory that competition for resources between microbes and vertebrates causes microbes to be selected to make these resources unpalatable to vertebrates. That is, fruit rots, seeds mould and meat spoils, in part, because microbes gain a selective advantage if they can alter the properties of these resources to avoid losing the resources to vertebrate consumers. A previous model had failed to find circumstances in which such a costly spoilage trait could flourish; here, we present a simple analytic model of a general situation where costly microbial spoilage is selected and persists. We argue that the key difference between the two models lies in their treatments of microbial dispersal. If microbial dispersal is sufficiently spatially constrained that different resource items can have differing microbial communities, then spoilage will be selected; however, if microbial dispersal has a strong homogenizing effect on the microbial community then spoilage will not be selected. We suspect that both regimes will exist in the natural world, and suggest how future empirical studies could explore the influence of microbial dispersal on spoilage.
Snowshoe hares display limited phenotypic plasticity to mismatch in seasonal camouflage
Authors: Zimova Marketa , Mills L. Scott , Lukacs Paul M. , Mitchell Michael S.
Published: March 2014

As duration of snow cover decreases owing to climate change, species undergoing seasonal colour moults can become colour mismatched with their background. The immediate adaptive solution to this mismatch is phenotypic plasticity, either in phenology of seasonal colour moults or in behaviours that reduce mismatch or its consequences. We observed nearly 200 snowshoe hares across a wide range of snow conditions and two study sites in Montana, USA, and found minimal plasticity in response to mismatch between coat colour and background. We found that moult phenology varied between study sites, likely due to differences in photoperiod and climate, but was largely fixed within study sites with only minimal plasticity to snow conditions during the spring white-to-brown moult. We also found no evidence that hares modify their behaviour in response to colour mismatch. Hiding and fleeing behaviours and resting spot preference of hares were more affected by variables related to season, site and concealment by vegetation, than by colour mismatch. We conclude that plasticity in moult phenology and behaviours in snowshoe hares is insufficient for adaptation to camouflage mismatch, suggesting that any future adaptation to climate change will require natural selection on moult phenology or behaviour.
D-A-D structured organic molecules with diketopyrrolopyrrole acceptor unit for solution-processed organic solar cells
Authors: Zhang Jing , He Chang , Zhang Zhi-Guo , Deng Dan , Zhang Maojie , Li Yongfang
Published: March 2014

Four solution-processable D-A-D structured organic molecules with diketopyrrolopyrrole (DPP) as acceptor unit and triphenylamine (TPA) or (4-hexyl)thieno [3,2-b]thiophene (HTT) as donor unit, DPP8-TPA, DPP8-TPA-OR, DPP6-HTT and DPP8-HTT, were designed and synthesized for the application as donor materials in solution-processed organic solar cells (OSCs). The molecules show broad absorption and relatively lower highest occupied molecular orbital energy levels. Photovoltaic properties of the molecules were investigated by fabricating the bulk-heterojunction OSCs with the molecules as donor and PC
71
BM as acceptor. Power conversion efficiency of the OSC based on DPP8-HTT reached 1.5% under the illumination of AM1.5, 100 mW cm
−2
.
Structure and magnetism of the A site scandium perovskite (Sc
0.94
Mn
0.06
)Mn
0.65
Ni
0.35
O
3
synthesized at high pressure
Authors: Thomas Chris I. , Suchomel Matthew R. , Duong Giap V. , Fogg Andrew M. , Claridge John B. , Rosseinsky Matthew J.
Published: March 2014

Scandium perovskite (Sc
0.94
Mn
0.06
)Mn
0.65
Ni
0.35
O
3
, synthesized at high pressure and high temperature, has a triclinic structure (space group

) at room temperature and ambient pressure with a √2
a
p
×√2
a
p
×2
a
p
structure with
α
≈90
°
,
β
≈89
°
,
γ
≈90
°
. Magnetic measurements show that the material displays Curie–Weiss behaviour above 50 K with
C
=2.11 emu K mol
−1
(
μ
eff
=4.11 μ
B
per formula unit) and
θ
=−95.27 K. Bond valence sum analysis of the crystal structure shows that manganese is present in three different oxidation states (+2, +3, +4), with the +2 oxidation state on the A site resulting in a highly tilted perovskite structure (average tilt 21.2
°
compared with 15.7
°
calculated for LaCaMnNbO
6
), giving the formula

.
Controllable fabrication of ultrathin free-standing graphene films
Authors: Chen Jianyi , Guo Yunlong , Huang Liping , Xue Yunzhou , Geng Dechao , Liu Hongtao , Wu Bin , Yu Gui , Hu Wenping , Liu Yunqi , Zhu Daoben
Published: March 2014

Graphene free-standing film-like or paper-like materials have attracted great attention due to their intriguing electronic, optical and mechanical properties and potential application in chemical filters, molecular storage and supercapacitors. Although significant progress has been made in fabricating graphene films or paper, there is still no effective method targeting ultrathin free-standing graphene films (UFGFs). Here, we present a modified filtration assembly method to prepare these ultrathin films. With this approach, we have fabricated a series of ultrathin free-standing graphene oxide films and UFGFs, up to 40 mm in diameter, with controllable thickness from micrometre to nanoscale (approx. 40 nm) dimensions. This method can be easily scaled up and the films display excellent optical, electrical and electrochemical properties. The ability to produce UFGFs from graphene oxide with a scalable, low-cost approach should take us a step closer to real-world applications of graphene.
Dichlorido[N-(N,N-dimethylcarbamimidoyl)-N′,N′,4-trimethylbenzohydrazonamide]platinum(II) nitromethane hemisolvate
Authors: Bolotin Dmitrii S. , Bokach Nadezha A. , Haukka Matti
Published: March 2014

In the title compound, [PtCl2(C13H21N5)]·0.5CH3NO2, the PtIIatom is coordinated in a slightly distorted square-planar geometry by two Cl atoms and two N atoms of the bidentate ligand. The (1,3,5-triazapentadiene)PtIImetalla ring is slightly bent and does not conjugate with the aromatic ring. In the crystal, N—H...Cl hydrogen bonds link the complex molecules, forming chains along [001]. The nitromethane solvent molecule shows half-occupancy and is disordered over two sets of sites about an inversion centre.
Diisopropyl [(4-methoxybenzamido)(p-tolyl)methyl]phosphonate
Authors: Fang Hua , Wang Guang-Qin , Chen Wei-Zhu , Yi Rui-Zao , Hong Zhuan
Published: March 2014

The asymmetric unit of the title compound, C22H30NO5P, contains two independent molecules in which the dihedral angles between the benzene rings are 82.0 (2) and 78.4 (2)°. In the crystal, each molecule forms an inversion dimerviaa pair of N—H...O(=P) hydrogen bonds.
1,5-Bis(2-hydroxy-3-methoxybenzylidene)carbonohydrazide methanol 0.47-solvate
Authors: Sow Mouhamadou Moustapha , Diouf Ousmane , Seck Matar , Barry Aliou Hamady , Gaye Mohamed
Published: March 2014

In the title compound, C17H18N4O5·0.47CH3OH, the virtually planar (r.m.s. deviation = 0.128 Å) carbonohydrazide molecule is located on a twofold axis and conformation of its C=N bonds isE. There are short intramolecular O—H...N hydrogen bonds between the hydroxy groups and hydrazide N atoms. In the crystal, bifurcated N—H...(O,O) hydrogen bonds assemble the carbonohydrazide molecules into a three-dimensional network. There areC2symmetric voids in this network, 47% of which are occupied by disordered methanol molecules.
tert-Butyl 2-{[5-(4-cyanophenyl)pyridin-3-yl]sulfonyl}acetate
Authors: Devarajegowda H. C. , Palakshamurthy B. S. , Manojkumar K. E. , Sreenivasa S.
Published: March 2014

In the title compound, C18H18N2O4S, the dihedral angle between the aromatic rings is 33.71 (9)° and an intramolecular C—H...O hydrogen bond closes anS(6) ring. In the crystal, molecules are linked by C—H...O and C—H...N hydrogen bonds to generate a three-dimensional network. A very weak aromatic π–π stacking interction is also observed [centroid–centroid separation = 3.9524 (10) Å].
2-(4,5-Dimethoxy-2-nitrophenyl)-4-methoxy-9-phenylsulfonyl-9H-carbazole-3-carbaldehyde
Authors: Narayanan P. , Sethusankar K. , Saravanan Velu , Mohanakrishnan Arasambattu K.
Published: March 2014

In the title compound, C28H22N2O8S, the carbazole ring system is roughly planar, with a maximum deviation of 0.084 (3) Å for the C atom connected to the 4,5-dimethoxy-2-nitrophenyl ring. The dihedral angle between the carbazole system and the dimethoxy-substituted nitrophenyl ring is 57.05 (10)°. The aldehyde C atom deviates by 0.164 (5) Å from its attached carbazole ring system. The molecular structure is stabilized by C—H...O interactions which generate twoS(6) and oneS(7) ring motif. In the crystal, molecules are linked by C—H...O hydrogen bonds, formingR33(15) ring motifs, which are further crosslinked byR32(19) ring motifs, resulting in (002) layers. The crystal packing also features C—H...π interactions.
Sample thickness and quantitative concentration measurements in BrK-edge XANES spectroscopy of organic materials
Authors: Leri Alessandra C. , Ravel Bruce
Published: March 2014

While XANES spectroscopy is an established tool for quantitative information on chemical structure and speciation, elemental concentrations are generally quantified by other methods. The edge step in XANES spectra represents the absolute amount of the measured element in the sample, but matrix effects and sample thickness complicate the extraction of accurate concentrations from XANES measurements, particularly at hard X-ray energies where the X-ray beam penetrates deeply into the sample. The present study demonstrates a method of quantifying concentration with a detection limit approaching 1 mg kg−1using information routinely collected in the course of a hard X-ray XANES experiment. The XANES normalization procedure unambiguously separates the signal of the absorber from any source of background. The effects of sample thickness on edge steps at the bromineK-edge were assessed and an empirical correction factor for use with samples of variable mass developed.
Non-crystallographic nets: characterization and first steps towards a classification
Authors: Moreira de Oliveira Montauban , Eon Jean-Guillaume
Published: March 2014

Non-crystallographic (NC) nets are periodic nets characterized by the existence of non-trivial bounded automorphisms. Such automorphisms cannot be associated with any crystallographic symmetry in realizations of the net by crystal structures. It is shown that bounded automorphisms of finite order form a normal subgroupF(N) of the automorphism group of NC nets (N,T). As a consequence, NC nets are unstable nets (they display vertex collisions in any barycentric representation) and, conversely, stable nets are crystallographic nets. The labelled quotient graphs of NC nets are characterized by the existence of an equivoltage partition (a partition of the vertex set that preserves label vectors over edges between cells). A classification of NC nets is proposed on the basis of (i) their relationship to the crystallographic net with a homeomorphic barycentric representation and (ii) the structure of the subgroupF(N).
Maternal depression, antidepressant prescriptions, and congenital anomaly risk in offspring: a population‐based cohort study
Authors: Ban L , Gibson JE , West J , Fiaschi L , Sokal R , Smeeth L , Doyle P , Hubbard RB , Tata LJ
Published: March 2014

Objective

To estimate risks of major congenital anomaly (MCA) among children of mothers prescribed antidepressants during early pregnancy or diagnosed with depression but without antidepressant prescriptions.

Design

Population‐based cohort study.

Setting

Linked UK maternal–child primary care records.

Population

A total of 349 127 singletons liveborn between 1990 and 2009.

Methods

Odds ratios adjusted for maternal sociodemographics and comorbidities (aORs) were calculated for MCAs, comparing women with first‐trimester selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs) and women with diagnosed but unmedicated depression, or women without diagnosed depression.

Main outcome measures

Fourteen system‐specific MCA groups classified according to the European Surveillance of Congenital Anomalies and five specific heart anomaly groups.

Results

Absolute risks of MCA were 2.7% (95% confidence interval, 95% CI, 2.6–2.8%) in children of mothers without diagnosed depression, 2.8% (95% CI 2.5–3.2%) in children of mothers with unmedicated depression, and 2.7% (95% CI 2.2–3.2%) and 3.1% (95% CI 2.2–4.1%) in children of mothers with SSRIs or TCAs, respectively. Compared with women without depression, MCA overall was not associated with unmedicated depression (aOR 1.07, 95% CI 0.96–1.18), SSRIs (aOR 1.01, 95% CI 0.88–1.17), or TCAs (aOR 1.09, 95% CI 0.87–1.38). Paroxetine was associated with increased heart anomalies (absolute risk 1.4% in the exposed group compared with 0.8% in women without depression; aOR 1.78, 95% CI 1.09–2.88), which decreased marginally when compared with women with diagnosed but unmedicated depression (aOR 1.67, 95% CI 1.00–2.80).

Conclusions

Overall MCA risk did not increase with maternal depression or with antidepressant prescriptions. Paroxetine was associated with increases of heart anomalies, although this could represent a chance finding from a large number of comparisons undertaken.
Regions with regionalism? The rescaling of interest groups in sixEuropean states
Authors: Keating Michael , Wilson Alex
Published: March 2014

In manyEuropean countries a regional or meso level of government has emerged, with significant policy responsibilities. It has been suggested that the representation of social and economic interests has not followed, so that policy communities remain state‐wide, giving ‘regions without regionalism’. This study of interest groups in sixEuropean states examines their adaptation to devolution, focusing on organisation, cognitive change and relationships. It finds there has been a regionalisation of interest representation, but it is uneven, depending on the strength of regional government, territorial identities and the interests of social actors. Business, trades unions, farmer organisations and environmental groups are all cross‐pressured on the regional question. The region is emerging in some cases as a site of interest intermediation. Territorial policy communities are emerging in some regions, but in most cases these supplement, rather than replace, state‐wide policy communities.
Genetic variation amongst biotypes of Dactylopius tomentosus
Authors: Mathenge Catherine W. , Riegler Markus , Beattie G. Andrew C. , Spooner‐Hart Robert N. , Holford Paul
Published: March 2014

The tomentose cochineal scale insect, Dactylopius tomentosus (Lamarck) (Hemiptera: Dactylopiidae), is an important biological control agent against invasive species of Cylindropuntia (Caryophyllales: Cactaceae). Recent studies have demonstrated that this scale is composed of host‐affiliated biotypes with differential host specificity and fitness on particular host species. We investigated genetic variation and phylogenetic relationships among D. tomentosus biotypes and provenances to examine the possibility that genetic diversity may be related to their host‐use pattern, and whether their phylogenetic relationships would give insights into taxonomic relatedness of their host plants. Nucleotide sequence comparison was accomplished using sequences of the mitochondrial cytochrome c oxidase I (COI) gene. Sequences of individuals from the same host plant within a region were identical and characterized by a unique haplotype. Individuals belonging to the same biotype but from different regions had similar haplotypes. However, haplotypes were not shared between different biotypes. Phylogenetic analysis grouped the monophyletic D. tomentosus into 3 well‐resolved clades of biotypes. The phylogenetic relationships and clustering of biotypes corresponded with known taxonomic relatedness of their hosts. Two biotypes, Fulgida and Mamillata, tested positive for Wolbachia (α‐Proteobacteria), a common endosymbiont of insects. The Wolbachia sequences were serendipitously detected by using insect‐specific COI DNA barcoding primers and are most similar to Wolbachia Supergroup F strains. This study is the first molecular characterization of cochineal biotypes that, together with Wolbachia sequences, contribute to the better identification of the biotypes of cochineal insects and to the biological control of cacti using host‐specific biotypes of the scale.