bluuebunny/crossref_metadata_2025 huggingface dataset:
A method for determining average damage depth of sawn crystalline silicon wafers
Authors: Sopori B. , Devayajanam S. , Basnyat P.
Published: April 2016

The depth of surface damage (or simply, damage) in crystalline silicon wafers, caused by wire sawing of ingots, is determined by performing a series of minority carrier lifetime (MCLT) measurements. Samples are sequentially etched to remove thin layers from each surface and MCLT is measured after each etch step. The thickness-removed (δt) at which the lifetime reaches a peak value corresponds to the damage depth. This technique also allows the damage to be quantified in terms of effective surface recombination velocity (Seff). To accomplish this, the MCLT data are converted into an Seff vs δt plot, which represents a quantitative distribution of the degree of damage within the surface layer. We describe a wafer preparation procedure to attain reproducible etching and MCLT measurement results. We also describe important characteristics of an etchant used for controllably removing thin layers from the wafer surfaces. Some typical results showing changes in the MCLT vs δt plots for different cutting parameters are given.
Guest dependent Brillouin and Raman scattering studies of zeolitic imidazolate framework-8 (ZIF-8) under external pressure
Authors: Radhakrishnan Dhanya , Narayana Chandrabhas
Published: April 2016

We have investigated the pressure dependence of the acoustic modes of zeolitic imidazolate framework (ZIF-8) in different pressure transmitting mediums and also under non-hydrostatic conditions using high pressure Brillouin spectroscopy. Our study shows the pressure induced flexibility and dynamics of ZIF-8 framework as well as a huge increase in the acoustic velocities on applying external pressure, illustrating the role of guest in enhancing the elastic properties of the framework. In fact, the elastic constant C11 of the guest incorporated ZIF-8 increases by ∼183% on applying a pressure of only 1.47 GPa. The pressure transmitting medium also plays an important role in controlling the gate opening behaviour of ZIF-8. Pressure dependent Raman study shows significant changes in the modes of ZIF-8 as well as that of that of the pressure transmitting medium which is entrapped within the framework, indicating that the interaction between the framework and guest is responsible for the medium dependent changes observed in the Brillouin spectra.
Enhancing the accuracy of the Fowler method for monitoring non-constant work functions
Authors: Friedl R.
Published: April 2016

The Fowler method is a prominent non-invasive technique to determine the absolute work function of a surface based on the photoelectric effect. The evaluation procedure relies on the correlation of the photocurrent with the incident photon energy hν which is mainly dependent on the surface work function χ. Applying Fowler’s theory of the photocurrent, the measurements can be fitted by the theoretical curve near the threshold hν⪆χ yielding the work function χ and a parameter A. The straightforward experimental implementation of the Fowler method is to use several particular photon energies, e.g. via interference filters. However, with a realization like that the restriction hν ≈ χ can easily be violated, especially when the work function of the material is decreasing during the measurements as, for instance, with coating or adsorption processes. This can lead to an overestimation of the evaluated work function value of typically some 0.1 eV, reaching up to more than 0.5 eV in an unfavorable case. A detailed analysis of the Fowler theory now reveals the background of that effect and shows that the fit-parameter A can be used to assess the accuracy of the determined value of χ conveniently during the measurements. Moreover, a scheme is introduced to quantify a potential overestimation and to perform a correction to χ to a certain extent. The issues are demonstrated exemplarily at the monitoring of the work function reduction of a stainless steel sample surface due to caesiation.
CdTe Timepix detectors for single-photon spectroscopy and linear polarimetry of high-flux hard x-ray radiation
Authors: Hahn C. , Weber G. , Märtin R. , Höfer S. , Kämpfer T. , Stöhlker Th.
Published: April 2016

Single-photon spectroscopy of pulsed, high-intensity sources of hard X-rays — such as laser-generated plasmas — is often hampered by the pileup of several photons absorbed by the unsegmented, large-volume sensors routinely used for the detection of high-energy radiation. Detectors based on the Timepix chip, with a segmentation pitch of 55 μm and the possibility to be equipped with high-Z sensor chips, constitute an attractive alternative to commonly used passive solutions such as image plates. In this report, we present energy calibration and characterization measurements of such devices. The achievable energy resolution is comparable to that of scintillators for γ spectroscopy. Moreover, we also introduce a simple two-detector Compton polarimeter setup with a polarimeter quality of (98 ± 1)%. Finally, a proof-of-principle polarimetry experiment is discussed, where we studied the linear polarization of bremsstrahlung emitted by a laser-driven plasma and found an indication of the X-ray polarization direction depending on the polarization state of the incident laser pulse.
Influence of intrinsic decoherence on tripartite entanglement and bipartite fidelity of polar molecules in pendular states
Authors: Han Jia-Xing , Hu Yuan , Jin Yu , Zhang Guo-Feng
Published: April 2016

An array of ultracold polar molecules trapped in an external electric field is regarded as a promising carrier of quantum information. Under the action of this field, molecules are compelled to undergo pendular oscillations by the Stark effect. Particular attention has been paid to the influence of intrinsic decoherence on the model of linear polar molecular pendular states, thereby we evaluate the tripartite entanglement with negativity, as well as fidelity of bipartite quantum systems for input and output signals using electric dipole moments of polar molecules as qubits. According to this study, we consider three typical initial states for both systems, respectively, and investigate the temporal evolution with variable values of the external field intensity, the intrinsic decoherence factor, and the dipole-dipole interaction. Thus, we demonstrate the sound selection of these three main parameters to obtain the best entanglement degree and fidelity.
Microscopic model for all optical switching in ferromagnets
Authors: Cornelissen T. D. , Córdoba R. , Koopmans B.
Published: April 2016

The microscopic mechanism behind the all optical switching (AOS) in ferromagnets has triggered intense scientific debate. Here, the microscopic three-temperature model is utilized to describe AOS in a perpendicularly magnetized ferromagnetic Co/Pt system. We demonstrate that AOS in such a ferromagnet can be explained with the Inverse Faraday Effect (IFE). The influence of the strength and lifetime of the IFE induced field pulse on the switching process are investigated. We found that because of strong spin-orbit coupling, the minimal lifetime of the IFE needed to obtain switching is of the order of 0.1 ps, which is shorter than previously assumed. Moreover, spatial images of the domain pattern after AOS in Co/Pt, as well as their dependence on applying an opposite magnetic field, are qualitatively reproduced.
On-chip mid-infrared gas detection using chalcogenide glass waveguide
Authors: Han Z. , Lin P. , Singh V. , Kimerling L. , Hu J. , Richardson K. , Agarwal A. , Tan D. T. H.
Published: April 2016

We demonstrate an on-chip sensor for room-temperature detection of methane gas using a broadband spiral chalcogenide glass waveguide coupled with off-chip laser and detector. The waveguide is fabricated using UV lithography patterning and lift-off after thermal evaporation. We measure the intensity change due to the presence and concentration of methane gas in the mid-infrared (MIR) range. This work provides an approach for broadband planar MIR gas sensing.
Three-dimensional treatment of nonequilibrium dynamics and higher order elasticity
Authors: Lott Martin , Payan Cédric , Garnier Vincent , Vu Quang A. , Eiras Jesús N. , Remillieux Marcel C. , Le Bas Pierre-Yves , Ulrich T. J.
Published: April 2016

This letter presents a three-dimensional model to describe the complex behavior of nonlinear mesoscopic elastic materials such as rocks and concrete. Assuming isotropy and geometric contraction of principal stress axes under dynamic loading, the expression of elastic wave velocity is derived, based on the second-order elastic constants (λ,μ), third-order elastic constants (l, m, n), and a parameter α of nonclassical nonlinear elasticity resulting from conditioning. We demonstrate that both softening and recovering of the elastic properties under dynamic loading is an isotropic effect related to the strain tensor. The measurement of the conditioning is achieved using three polarized waves. The model allows the evaluation of the third-order elastic constants uncoupled from conditioning and viscoelastic effects. The values obtained are similar to those reported in the literature using quasi-static loading.
Hybrid thermionic-photovoltaic converter
Authors: Datas A.
Published: April 2016

A conceptual device for the direct conversion of heat into electricity is presented. This concept hybridizes thermionic (TI) and thermophotovoltaic (TPV) energy conversion in a single thermionic-photovoltaic (TIPV) solid-state device. This device transforms into electricity both the electron and photon fluxes emitted by an incandescent surface. This letter presents an idealized analysis of this device in order to determine its theoretical potential. According to this analysis, the key advantage of this converter, with respect to either TPV or TI, is the higher power density in an extended temperature range. For low temperatures, TIPV performs like TPV due to the negligible electron flux. On the contrary, for high temperatures, TIPV performs like TI due to the great enhancement of the electron flux, which overshadows the photon flux contribution. At the intermediate temperatures, ∼1650 K in the case of this particular study, I show that the power density potential of TIPV converter is twice as great as that of TPV and TI. The greatest impact concerns applications in which the temperature varies in a relatively wide range, for which averaged power density enhancement above 500% is attainable.
Noise-supported actuator: Coherent resonance in the oscillations of a micrometer-sized object under a direct current-voltage
Authors: Kurimura Tomo , Ichikawa Masatoshi
Published: April 2016

Noise supported regular motion in a micro-fluidic environment is studied. Recently, it was reported that an aqueous droplet in an oil phase exhibited rhythmic back-and-forth motion under stationary direct current voltage between the cone-shaped electrodes, where the oscillating water droplet moves on a limit cycle orbital. We now confirm that a combination of the limit cycle nature and white noise supports and enhances the regular motion of the object through coherent resonance. The present result will open a way to design an efficient machinery in microfluidic and micromechanical devices.
Semiconducting ZnSnN2 thin films for Si/ZnSnN2 p-n junctions
Authors: Qin Ruifeng , Cao Hongtao , Liang Lingyan , Xie Yufang , Zhuge Fei , Zhang Hongliang , Gao Junhua , Javaid Kashif , Liu Caichi , Sun Weizhong
Published: April 2016

ZnSnN2 is regarded as a promising photovoltaic absorber candidate due to earth-abundance, non-toxicity, and high absorption coefficient. However, it is still a great challenge to synthesize ZnSnN2 films with a low electron concentration, in order to promote the applications of ZnSnN2 as the core active layer in optoelectronic devices. In this work, polycrystalline and high resistance ZnSnN2 films were fabricated by magnetron sputtering technique, then semiconducting films were achieved after post-annealing, and finally Si/ZnSnN2 p-n junctions were constructed. The electron concentration and Hall mobility were enhanced from 2.77 × 1017 to 6.78 × 1017 cm−3 and from 0.37 to 2.07 cm2 V−1 s−1, corresponding to the annealing temperature from 200 to 350 °C. After annealing at 300 °C, the p-n junction exhibited the optimum rectifying characteristics, with a forward-to-reverse ratio over 103. The achievement of this ZnSnN2-based p-n junction makes an opening step forward to realize the practical application of the ZnSnN2 material. In addition, the nonideal behaviors of the p-n junctions under both positive and negative voltages are discussed, in hope of suggesting some ideas to further improve the rectifying characteristics.
Resistive switching and voltage induced modulation of tunneling magnetoresistance in nanosized perpendicular organic spin valves
Authors: Göckeritz Robert , Homonnay Nico , Müller Alexander , Fuhrmann Bodo , Schmidt Georg
Published: April 2016

Nanoscale multifunctional perpendicular organic spin valves have been fabricated. The devices based on an La0.7Sr0.3MnO3/Alq3/Co trilayer show resistive switching of up to 4-5 orders of magnitude and magnetoresistance as high as -70% the latter even changing sign when voltage pulses are applied. This combination of phenomena is typically observed in multiferroic tunnel junctions where it is attributed to magnetoelectric coupling between a ferromagnet and a ferroelectric material. Modeling indicates that here the switching originates from a modification of the La0.7Sr0.3MnO3 surface. This modification influences the tunneling of charge carriers and thus both the electrical resistance and the tunneling magnetoresistance which occurs at pinholes in the organic layer.
Planning for subacute care: predicting demand using acute activity data
Authors: Green Janette P. , McNamee Jennifer P. , Kobel Conrad , Seraji Md Habibur R. , Lawrence Suanne J.
Published: April 2016

Objective
The aim of the present study was to develop a robust model that uses the concept of ‘rehabilitation-sensitive’ Diagnosis Related Groups (DRGs) in predicting demand for rehabilitation and geriatric evaluation and management (GEM) care following acute in-patient episodes provided in Australian hospitals.

Methods
The model was developed using statistical analyses of national datasets, informed by a panel of expert clinicians and jurisdictional advice. Logistic regression analysis was undertaken using acute in-patient data, published national hospital statistics and data from the Australasian Rehabilitation Outcomes Centre.

Results
The predictive model comprises tables of probabilities that patients will require rehabilitation or GEM care after an acute episode, with columns defined by age group and rows defined by grouped Australian Refined (AR)-DRGs.

Conclusions
The existing concept of rehabilitation-sensitive DRGs was revised and extended. When applied to national data, the model provided a conservative estimate of 83% of the activity actually provided. An example demonstrates the application of the model for service planning.

What is known about the topic?
Health service planning is core business for jurisdictions and local areas. With populations ageing and an acknowledgement of the underservicing of subacute care, it is timely to find improved methods of estimating demand for this type of care. Traditionally, age–sex standardised utilisation rates for individual DRGs have been applied to Australian Bureau of Statistics (ABS) population projections to predict the future need for subacute services. Improved predictions became possible when some AR-DRGs were designated ‘rehabilitation-sensitive’. This improved methodology has been used in several Australian jurisdictions.

What does this paper add?
This paper presents a new tool, or model, to predict demand for rehabilitation and GEM services based on in-patient acute activity. In this model, the methodology based on rehabilitation-sensitive AR-DRGs has been extended by updating them to AR-DRG Version 7.0, quantifying the level of ‘sensitivity’ and incorporating the patient’s age to improve the prediction of demand for subacute services.

What are the implications for practitioners?
The predictive model takes the form of tables of probabilities that patients will require rehabilitation or GEM care after an acute episode and can be applied to acute in-patient administrative datasets in any Australian jurisdiction or local area. The use of patient-level characteristics will enable service planners to improve their forecasting of demand for these services. Clinicians and jurisdictional representatives consulted during the project regarded the model favourably and believed that it was an improvement on currently available methods.
Effect of Single Layer Centrifugation on reactive oxygen species and sperm mitochondrial membrane potential in cooled stallion semen
Authors: Morrell J. M. , Lagerqvist A. , Humblot P. , Johannisson A.
Published: April 2016

Additional means are needed for evaluating the quality of stallion spermatozoa in semen doses for AI. Mitochondrial membrane potential (ΔΨm) has been linked to fertility in some species, but is rarely used in the evaluation of cooled stallion semen; metabolic activity may be associated with reactive oxygen species production (ROS). In the present study, ΔΨm and ROS production were measured in doses of cooled stallion semen. The effect of colloid centrifugation on these parameters was also investigated. In this case, colloid centrifugation involves centrifuging a sperm sample through a silane-coated silica colloid formulation to retrieve the most robust spermatozoa. High and low ΔΨm in cooled stallion semen varied between stallions and between ejaculates, but was not affected by single-layer centrifugation (SLC). The SLC-selected spermatozoa produced significantly less hydrogen peroxide than controls (P < 0.001), which could explain the increased longevity and retention of fertilising capacity seen in previous studies. For SLC samples, ΔΨm was positively associated with viable spermatozoa that were not producing reactive oxygen species (r = 0.49; P < 0.001) and negatively associated with ROS production (for superoxide: r = –0.4, P < 0.01; for hydrogen peroxide: r = –0.39, P < 0.05). There was no clear association between ΔΨm and ROS production in control samples.
Metabolomics-assisted proteomics identifies succinylation and SIRT5 as important regulators of cardiac function
Authors: Sadhukhan Sushabhan , Liu Xiaojing , Ryu Dongryeol , Nelson Ornella D. , Stupinski John A. , Li Zhi , Chen Wei , Zhang Sheng , Weiss Robert S. , Locasale Jason W. , Auwerx Johan , Lin Hening
Published: April 2016

Significance

Lysine succinylation is a recently discovered protein posttranslational modification and SIRT5 is an efficient desuccinylase. Although many mammalian proteins have recently been found to be regulated by lysine succinylation and SIRT5, the physiological significance of succinylation and SIRT5 remains unknown. Here we report that protein lysine succinylation predominantly accumulates in the heart when
Sirt5
is deleted.
Sirt5
-deficient mice exhibit defective fatty acid metabolism, decreased ATP production, and hypertrophic cardiomyopathy. Our data suggest that regulating heart metabolism and function is a major physiological role of lysine succinylation and SIRT5.
Asymmetric arginine dimethylation of RelA provides a repressive mark to modulate TNFα/NF-κB response
Authors: Reintjes Anja , Fuchs Julian E. , Kremser Leopold , Lindner Herbert H. , Liedl Klaus R. , Huber Lukas A. , Valovka Taras
Published: April 2016

Significance

The transcription factor nuclear factor kappa B (NF-κB) plays a vital role in cellular immune, stress, and proliferative responses by regulating genes. To maintain correct execution of the genetic program and to prevent pathologies (e.g., chronic inflammation), the activation of NF-κB has to be transient and precisely controlled. We describe a unique inhibitory mechanism that mediates NF-κB–dependent regulation of inflammation-associated genes and uses arginine methylation of the RelA subunit of NF-κB by protein arginine methyltransferase 1. This modification reduces the DNA-binding affinity of RelA, altering the recruitment to gene promoters and the transcriptional potency of NF-κB. This may be developed into an approach to inhibit the pathological functions of NF-κB.
Perceptual learning modifies the functional specializations of visual cortical areas
Authors: Chen Nihong , Cai Peng , Zhou Tiangang , Thompson Benjamin , Fang Fang
Published: April 2016

Significance

Using transcranial magnetic stimulation and functional magnetic resonance imaging techniques, we demonstrate here that the transfer of perceptual learning from a task involving coherent motion to a task involving noisy motion can induce a functional substitution of V3A (one of the visual areas in the extrastriate visual cortex) for MT+ (middle temporal/medial superior temporal cortex) to process noisy motion. This finding suggests that perceptual learning in visually normal adults shapes the functional architecture of the brain in a much more pronounced way than previously believed. The effects of perceptual learning extend far beyond the retuning of specific neural populations that mediate performance of the trained task. Learning could dramatically modify the inherent functional specializations of visual cortical areas and dynamically reweight their contributions to perceptual decisions based on their representational qualities.
Direct imaging of magnetic field-driven transitions of skyrmion cluster states in FeGe nanodisks
Authors: Zhao Xuebing , Jin Chiming , Wang Chao , Du Haifeng , Zang Jiadong , Tian Mingliang , Che Renchao , Zhang Yuheng
Published: April 2016

Significance

The rapid growth of data volume demands faster and denser storage devices. The noncoplanar swirling spin texture, known as magnetic skyrmion, has potential application in future memory devices. To realize such applications, it is essential to understand the properties of individual skyrmion in patterned nanoelements. While quite a number of theoretical efforts have been made in this field, direct experimental demonstration in such a real modeling system is a challenge. Here, we report the direct visualization of skyrmion cluster states in FeGe nanodisks. We determine the common relationship among the temperature, magnetic field, and disk size. These results have an immediate implication for designing future skyrmion-based devices.
Comparison of syncytiotrophoblast generated from human embryonic stem cells and from term placentas
Authors: Yabe Shinichiro , Alexenko Andrei P. , Amita Mitsuyoshi , Yang Ying , Schust Danny J. , Sadovsky Yoel , Ezashi Toshihiko , Roberts R. Michael
Published: April 2016

Significance

Syncytiotrophoblast (STB) is responsible for nutrient and gas exchange in the human placenta. STB also forms when human embryonic stem cells (ESCs) differentiate to trophoblast. Here we compare ESC-derived STB with cytotrophoblasts isolated from term placentas before and after such cells had fused to form STB. Although both types of STB expressed all common trophoblast marker genes, there were dissimilarities indicative of altered function and ontology. We propose that STB derived from ESCs represents syncytial tissue encountered at the initiation of placental development. These cells may provide the first in vitro model for studying origins of diseases of placentation ranging from implantation failure and early pregnancy loss to intrauterine growth retardation and preeclampsia.
Analysis of fast-ion Dα data from the National Spherical Torus Experiment
Authors: Heidbrink W.W. , Ruskov E. , Liu D. , Stagner L. , Fredrickson E.D. , Podestà M. , Bortolon A.
Published: April 2016

Measured fast-ion

D

α

(FIDA) data from an extensive NSTX database are compared to ‘classical’ predictions that neglect transport by instabilities. Even in the absence of appreciable MHD, in many cases, the profile peaks at smaller major radius and the profile is broader than the predictions. Abrupt large-amplitude MHD events flatten the FIDA profile, as do most toroidal Alfvén eigenmode (TAE) avalanche events. Generally, the onset of a long-lived mode also flattens the FIDA profile.
Unconventional Gas and Oil Development in the United States: Economic Experience and Policy Issues
Authors: Kelsey Timothy W. , Partridge Mark D. , White Nancy E.
Published: April 2016

This paper examines the economic experience of past energy booms and that of current unconventional shale gas and oil development. We focus on key economic characteristics of gas and oil production such as its employment potential, its geography, and its boom‐bust nature. This background is used to discuss important economic policy issues arising with unconventional oil and gas development such as taxation, governmental use of those revenues, preemption, and equity in the distribution of costs and benefits. The paper concludes with economic policy recommendations for states and communities affected by such development including not viewing oil and gas development as an effective long‐run economic development strategy, leveraging short‐run financial gains from the development into permanent advantages, and strengthening the capacity for local governments to understand and manage this activity.
Evaluation of Bacterial Effects on Folic Acid Loss in Fortified, Nixtamalized Corn Masa Flour
Authors: Adolphson Stephen J. , Dunn Michael L. , Nielsen‐Barrows Sarah , Eggett Dennis L. , Steele Frost M.
Published: April 2016

Many Mexican women are deficient in folic acid. Fortification of the corn tortilla could be an effective way to help increase the folic acid levels among the Mexican population. Previous studies have shown significant folic acid losses in the masa dough as it is held before baking. This loss in folic acid could be owing to utilization by lactic acid bacteria naturally present in the masa. The objective of this study was to determine the effect of bacteria native to corn masa on the folic acid content in masa. Bacteria in dough samples from six mills in Guadalajara, Mexico, were isolated and identified. Bacterial isolates were inoculated into sterile fortified corn masa flour, which was converted to masa and held at 56°C for 0, 3, and 6 h, replicating the conditions of freshly milled masa as held before baking. All samples, including the control, showed losses of folic acid between 66 and 79% w/w in the first 3 h of incubation. Because folic acid degradation in the sterile control sample was not different than the inoculated sample results, the decline in folic acid was not owing to bacteria (mainly Streptococcus spp.) present in the masa flour but appeared to be a chemical degradation related to time and temperature.
Experimental demonstration of an Allee effect in microbial populations
Authors: Kaul RajReni B. , Kramer Andrew M. , Dobbs Fred C. , Drake John M.
Published: April 2016

Microbial populations can be dispersal limited. However, microorganisms that successfully disperse into physiologically ideal environments are not guaranteed to establish. This observation contradicts the Baas-Becking tenet: ‘Everything is everywhere, but the environment selects’. Allee effects, which manifest in the relationship between initial population density and probability of establishment, could explain this observation. Here, we experimentally demonstrate that small populations of
Vibrio fischeri
are subject to an intrinsic demographic Allee effect. Populations subjected to predation by the bacterivore
Cafeteria roenbergensis
display both intrinsic and extrinsic demographic Allee effects. The estimated critical threshold required to escape positive density-dependence is around 5, 20 or 90 cells ml
−1
under conditions of high carbon resources, low carbon resources or low carbon resources with predation, respectively. This work builds on the foundations of modern microbial ecology, demonstrating that mechanisms controlling macroorganisms apply to microorganisms, and provides a statistical method to detect Allee effects in data.
The ANGPTL3-4-8 model, a molecular mechanism for triglyceride trafficking
Authors: Zhang Ren
Published: April 2016

Lipoprotein lipase (LPL) is a rate-limiting enzyme for hydrolysing circulating triglycerides (TG) into free fatty acids that are taken up by peripheral tissues. Postprandial LPL activity rises in white adipose tissue (WAT), but declines in the heart and skeletal muscle, thereby directing circulating TG to WAT for storage; the reverse is true during fasting. However, the mechanism for the tissue-specific regulation of LPL activity during the fed–fast cycle has been elusive. Recent identification of lipasin/angiopoietin-like 8 (Angptl8), a feeding-induced hepatokine, together with Angptl3 and Angptl4, provides intriguing, yet puzzling, insights, because all the three Angptl members are LPL inhibitors, and the deficiency (overexpression) of any one causes hypotriglyceridaemia (hypertriglyceridaemia). Then, why does nature need all of the three? Our recent data that Angptl8 negatively regulates LPL activity specifically in cardiac and skeletal muscles suggest an Angptl3-4-8 model: feeding induces Angptl8, activating the Angptl8–Angptl3 pathway, which inhibits LPL in cardiac and skeletal muscles, thereby making circulating TG available for uptake by WAT, in which LPL activity is elevated owing to diminished Angptl4; the reverse is true during fasting, which suppresses Angptl8 but induces Angptl4, thereby directing TG to muscles. The model suggests a general framework for how TG trafficking is regulated.
A small mitochondrial protein present in myzozoans is essential for malaria transmission
Authors: Klug Dennis , Mair Gunnar R. , Frischknecht Friedrich , Douglas Ross G.
Published: April 2016

Myzozoans (which include dinoflagellates, chromerids and apicomplexans) display notable divergence from their ciliate sister group, including a reduced mitochondrial genome and divergent metabolic processes. The factors contributing to these divergent processes are still poorly understood and could serve as potential drug targets in disease-causing protists. Here, we report the identification and characterization of a small mitochondrial protein from the rodent-infecting apicomplexan parasite
Plasmodium berghei
that is essential for development in its mosquito host. Parasites lacking the gene mitochondrial protein ookinete developmental defect (
mpodd
) showed malformed parasites that were unable to transmit to mosquitoes. Knockout parasites displayed reduced mitochondrial mass without affecting organelle integrity, indicating no role of the protein in mitochondrial biogenesis or morphology maintenance but a likely role in mitochondrial import or metabolism. Using genetic complementation experiments, we identified a previously unrecognized
Plasmodium falciparum
homologue that can rescue the
mpodd(−)
phenotype, thereby showing that the gene is functionally conserved. As far as can be detected,
mpodd
is found in myzozoans, has homologues in the phylum
Apicomplexa
and appears to have arisen in free-living dinoflagellates. This suggests that the MPODD protein has a conserved mitochondrial role that is important for myzozoans. While previous studies identified a number of essential proteins which are generally highly conserved evolutionarily, our study identifies, for the first time, a non-canonical protein fulfilling a crucial function in the mitochondrion during parasite transmission.
A synthetic, catalytic and theoretical investigation of an unsymmetrical SCN pincer palladacycle
Authors: Roffe Gavin W. , Boonseng Sarote , Baltus Christine B. , Coles Simon J. , Day Iain J. , Jones Rhiannon N. , Press Neil J. , Ruiz Mario , Tizzard Graham J. , Cox Hazel , Spencer John
Published: April 2016

The SCN ligand 2-{3-[(methylsulfanyl)methyl]phenyl}pyridine, 1, has been synthesized starting from an initial Suzuki–Miyaura (SM) coupling between 3-((hydroxymethyl)phenyl)boronic acid and 2-bromopyridine. The C–H activation of 1 within situformed Pd(MeCN)4(BF4)2has been studied and leads to a mixture of palladacycles, which were characterized by X-ray crystallography. The monomeric palladacycle LPdCl 6, where L-H = 1, has been synthesized, and tested in SM couplings of aryl bromides, where it showed moderate activity. Density functional theory and the atoms in molecules (AIM) method have been used to investigate the formation and bonding of 6, revealing a difference in the nature of the Pd–S and Pd–N bonds. It was found that S-coordination to the metal in the rate determining C–H bond activation step leads to better stabilization of the Pd(II) centre (by 13–28 kJ mol−1) than with N-coordination. This is attributed to the electron donating ability of the donor atoms determined by Bader charges. The AIM analysis also revealed that the Pd–N bonds are stronger than the Pd–S bonds influencing the stability of key intermediates in the palladacycle formation reaction pathway.
Influence of the porosity on the photoresponse of a liquid crystal elastomer
Authors: Kizilkan Emre , Strueben Jan , Jin Xin , Schaber Clemens F. , Adelung Rainer , Staubitz Anne , Gorb Stanislav N.
Published: April 2016

Azobenzene containing liquid crystal elastomers (LCEs) are among of the most prominent photoresponsive polymers due to their fast and reversible response to different light stimuli. To bring new functions into the present framework, novel modifications in bulk material morphology are required. Therefore, we produced azobenzene LCE free-standing films with different porosities. While the porosity provided macroscopic morphological changes, at the same time, it induced modifications in alignment of liquid crystal azobenzene units in the films. We found that a high porosity increased the photoresponse of the LCE in terms of bending angle with high significance. Moreover, the porous LCE films showed similar bending forces to those of pore-free LCE films.
Nonlinear electro-magneto-mechanical constitutive modelling of monolayer graphene
Authors: Sfyris D. , Sfyris G. I. , Bustamante R.
Published: April 2016

Using the classical theory of invariants for the specific class of graphene's symmetry, we constitutively characterize electro-magneto-mechanical interactions of graphene at continuum level. Graphene's energy depends on five arguments: the Finger strain tensor, the curvature tensor, the shift vector, the effective electric field intensity and the effective magnetic induction. The Finger strain tensor describes in- surface phenomena, the curvature tensor is responsible for the out-of-surface motions, while the shift vector is used due to the fact that graphene is a multilattice. The electric and the magnetic fields are described by the effective electric field intensity and the effective magnetic induction, respectively. An energy with the above arguments that also respects graphene's symmetries is found to have 42 invariants. Using these invariants, we evaluate all relevant measures by finding derivatives of the energy with respect to the five arguments of the energy. We also lay down the field equations that should be satisfied. These are the Maxwell equations, the momentum equation, the moment of momentum equation and the equation ruling the shift vector. Our framework is general enough to capture fully coupled processes in the finite deformation regime.
Understanding spatial distributions: negative density-dependence in prey causes predators to trade-off prey quantity with quality
Authors: Bijleveld Allert I. , MacCurdy Robert B. , Chan Ying-Chi , Penning Emma , Gabrielson Rich M. , Cluderay John , Spaulding Eric L. , Dekinga Anne , Holthuijsen Sander , ten Horn Job , Brugge Maarten , van Gils Jan A. , Winkler David W. , Piersma Theunis
Published: April 2016

Negative density-dependence is generally studied within a single trophic level, thereby neglecting its effect on higher trophic levels. The ‘functional response’ couples a predator's intake rate to prey density. Most widespread is a type II functional response, where intake rate increases asymptotically with prey density; this predicts the highest predator densities at the highest prey densities. In one of the most stringent tests of this generality to date, we measured density and quality of bivalve prey (edible cocklesCerastoderma edule) across 50 km² of mudflat, and simultaneously, with a novel time-of-arrival methodology, tracked their avian predators (red knotsCalidris canutus). Because of negative density-dependence in the individual quality of cockles, the predicted energy intake rates of red knots declined at high prey densities (a type IV, rather than a type II functional response). Resource-selection modelling revealed that red knots indeed selected areas of intermediate cockle densities where energy intake rates were maximized given their phenotype-specific digestive constraints (as indicated by gizzard mass). Because negative density-dependence is common, we question the current consensus and suggest that predators commonly maximize their energy intake rates at intermediate prey densities. Prey density alone may thus poorly predict intake rates, carrying capacity and spatial distributions of predators.
Maternal programming of offspring in relation to food availability in an insect (
Forficula auricularia
)
Authors: Raveh Shirley , Vogt Dominik , Kölliker Mathias
Published: April 2016

Maternal effects can induce adjustments in offspring phenotype to the environment experienced by the mother. Of particular interest is if mothers can programme their offspring to cope best under matching environmental conditions, but the evidence for such anticipatory maternal effects (AME) is limited. In this study, we manipulated experimentally the food availability experienced by mothers and their offspring in the European earwig (
Forficula auricularia
). Offspring produced by females that had access to high or low food quantities were cross-fostered to foster mothers experiencing matched or mismatched environments. Offspring experiencing food availability matching the one of their mothers had an increased survival to adulthood compared with offspring experiencing mismatched conditions. Females experiencing high food laid larger clutches. This clutch-size adjustment statistically explained the matching effect when offspring experienced high food, but not when experiencing low food conditions. There were no effects of matching on offspring growth and developmental rate. Overall, our study demonstrates that AME occurs in relation to food availability enhancing offspring survival to adulthood under matching food conditions.
Finding the gap: a brightness-based strategy for guidance in cluttered environments
Authors: Baird Emily , Dacke Marie
Published: April 2016

The ability to move safely between obstacles is critical for animals that fly rapidly through cluttered environments but surprisingly little is known about how they achieve this. Do they reactively avoid obstacles or do they instead fly towards the gaps between them? If they aim towards gaps, what information do they use to detect and fly through them? Here, we aim to answer these questions by presenting orchid bees with different apertures. When negotiating gaps, orchid bees locate and fly close to the point that gives them greatest clearance from the edges. The cue that they use to pinpoint this spot is the brightness gradient formed across the aperture. Furthermore, we find that orchid bees also rely on brightness cues to locate gaps that are sufficiently large to negotiate safely. The advantage of using brightness for locating and negotiating gaps in a cluttered environment is that it provides information about the safest path through obstacles, at least in a forest environment. This brightness-based guidance strategy for gap detection and negotiation represents a fast, computationally simple and efficient mechanism to identify the clearest path through a forest and is, therefore, likely to represent a more general mechanism used by other animals.
Factors influencing the effect size distribution of adaptive substitutions
Authors: Dittmar Emily L. , Oakley Christopher G. , Conner Jeffrey K. , Gould Billie A. , Schemske Douglas W.
Published: April 2016

The distribution of effect sizes of adaptive substitutions has been central to evolutionary biology since the modern synthesis. Early theory proposed that because large-effect mutations have negative pleiotropic consequences, only small-effect mutations contribute to adaptation. More recent theory suggested instead that large-effect mutations could be favoured when populations are far from their adaptive peak. Here we suggest that the distributions of effect sizes are expected to differ among study systems, reflecting the wide variation in evolutionary forces and ecological conditions experienced in nature. These include selection, mutation, genetic drift, gene flow, and other factors such as the degree of pleiotropy, the distance to the phenotypic optimum, whether the optimum is stable or moving, and whether new mutation or standing genetic variation provides the source of adaptive alleles. Our goal is to review how these factors might affect the distribution of effect sizes and to identify new research directions. Until more theory and empirical work is available, we feel that it is premature to make broad generalizations about the effect size distribution of adaptive substitutions important in nature.
Host behaviour–parasite feedback: an essential link between animal behaviour and disease ecology
Authors: Ezenwa Vanessa O. , Archie Elizabeth A. , Craft Meggan E. , Hawley Dana M. , Martin Lynn B. , Moore Janice , White Lauren
Published: April 2016

Animal behaviour and the ecology and evolution of parasites are inextricably linked. For this reason, animal behaviourists and disease ecologists have been interested in the intersection of their respective fields for decades. Despite this interest, most research at the behaviour–disease interface focuses either on how host behaviour affects parasites or how parasites affect behaviour, with little overlap between the two. Yet, the majority of interactions between hosts and parasites are probably reciprocal, such that host behaviour feeds back on parasites and vice versa. Explicitly considering these feedbacks is essential for understanding the complex connections between animal behaviour and parasite ecology and evolution. To illustrate this point, we discuss how host behaviour–parasite feedbacks might operate and explore the consequences of feedback for studies of animal behaviour and parasites. For example, ignoring the feedback of host social structure on parasite dynamics can limit the accuracy of predictions about parasite spread. Likewise, considering feedback in studies of parasites and animal personalities may provide unique insight about the maintenance of variation in personality types. Finally, applying the feedback concept to links between host behaviour and beneficial, rather than pathogenic, microbes may shed new light on transitions between mutualism and parasitism. More generally, accounting for host behaviour–parasite feedbacks can help identify critical gaps in our understanding of how key host behaviours and parasite traits evolve and are maintained.
Highly polymorphic colour vision in a New World monkey with red facial skin, the bald uakari (Cacajao calvus)
Authors: Corso Josmael , Bowler Mark , Heymann Eckhard W. , Roos Christian , Mundy Nicholas I.
Published: April 2016

Colour vision is highly variable in New World monkeys (NWMs). Evidence for the adaptive basis of colour vision in this group has largely centred on environmental features such as foraging benefits for differently coloured foods or predator detection, whereas selection on colour vision for sociosexual communication is an alternative hypothesis that has received little attention. The colour vision of uakaris (Cacajao) is of particular interest because these monkeys have the most dramatic red facial skin of any primate, as well as a unique fission/fusion social system and a specialist diet of seeds. Here, we investigate colour vision in a wild population of the bald uakari,C. calvus, by genotyping the X-linked opsin locus. We document the presence of a polymorphic colour vision system with an unprecedented number of functional alleles (six), including a novel allele with a predicted maximum spectral sensitivity of 555 nm. This supports the presence of strong balancing selection on different alleles at this locus. We consider different hypotheses to explain this selection. One possibility is that trichromacy functions in sexual selection, enabling females to choose high-quality males on the basis of red facial coloration. In support of this, there is some evidence that health affects facial coloration in uakaris, as well as a high prevalence of blood-borne parasitism in wild uakari populations. Alternatively, the low proportion of heterozygous female trichromats in the population may indicate selection on different dichromatic phenotypes, which might be related to cryptic food coloration. We have uncovered unexpected diversity in the last major lineage of NWMs to be assayed for colour vision, which will provide an interesting system to dissect adaptation of polymorphic trichromacy.
Colonization of the Scottish islands via long-distance Neolithic transport of red deer (Cervus elaphus)
Authors: Stanton David W. G. , Mulville Jacqueline A. , Bruford Michael W.
Published: April 2016

Red deer (Cervus elaphus) have played a key role in human societies throughout history, with important cultural significance and as a source of food and materials. This relationship can be traced back to the earliest human cultures and continues to the present day. Humans are thought to be responsible for the movement of a considerable number of deer throughout history, although the majority of these movements are poorly described or understood. Studying such translocations allows us to better understand ancient human–wildlife interactions, and in the case of island colonizations, informs us about ancient human maritime practices. This study uses DNA sequences to characterise red deer genetic diversity across the Scottish islands (Inner and Outer Hebrides and Orkney) and mainland using ancient deer samples, and attempts to infer historical colonization events. We show that deer from the Outer Hebrides and Orkney are unlikely to have originated from mainland Scotland, implying that humans introduced red deer from a greater distance. Our results are also inconsistent with an origin from Ireland or Norway, suggesting long-distance maritime travel by Neolithic people to the outer Scottish Isles from an unknown source. Common haplotypes and low genetic differentiation between the Outer Hebrides and Orkney imply common ancestry and/or gene flow across these islands. Close genetic proximity between the Inner Hebrides and Ireland, however, corroborates previous studies identifying mainland Britain as a source for red deer introductions into Ireland. This study provides important information on the processes that led to the current distribution of the largest surviving indigenous land mammal in the British Isles.
Functional definitions of parietal areas in human and non-human primates
Authors: Orban Guy A.
Published: April 2016

Establishing homologies between cortical areas in animal models and humans lies at the heart of translational neuroscience, as it demonstrates how knowledge obtained from these models can be applied to the human brain. Here, we review progress in using parallel functional imaging to ascertain homologies between parietal areas of human and non-human primates, species sharing similar behavioural repertoires. The human homologues of several areas along monkey IPS involved in action planning and observation, such as AIP, LIP and CIP, as well as those of opercular areas (SII complex), have been defined. In addition, uniquely human areas, such as the tool-use area in left anterior supramarginal gyrus, have also been identified.