Chiral Odd Generalized Parton Distributions in Position Space

We report on a calculation of the chiral odd generalized parton distributions (GPDs) for non-zero skewness $\zeta$ in transverse and longitudinal position spaces by taking Fourier transform with respect to the transverse and longitudinal momentum transfer respectively using overlaps of light-front wave functions (LFWFs).Comment: Presented at the 18 th International Spin Physics Symposium, University of Virginia, Charlottesville, Virginia, USA, October 6-11, 200

Unravelling the macro-evolutionary ecology of fish–jellyfish associations: life in the ‘gingerbread house’

Fish–jellyfish interactions are important factors contributing to fish stock success. Jellyfish can compete with fish for food resources, or feed on fish eggs and larvae, which works to reduce survivorship and recruitment of fish species. However, jellyfish also provide habitat and space for developing larval and juvenile fish which use their hosts as means of protection from predators and feeding opportunities, helping to reduce fish mortality and increase recruitment. Yet, relatively little is known about the evolutionary dynamics and drivers of such associations which would allow for their more effective incorporation into ecosystem models. Here, we found that jellyfish association is a probable adaptive anti-predator strategy for juvenile fish, more likely to evolve in benthic (fish living on the sea floor), benthopelagic (fish living just above the bottom of the seafloor), and reef-associating species than those adapted to other marine habitats. We also found that jellyfish association likely preceded the evolution of a benthic, benthopelagic, and reef-associating lifestyle rather than its evolutionary consequence, as we originally hypothesized. Considering over two-thirds of the associating fish identified here are of economic importance, and the wide-scale occurrence and diversity of species involved, it is clear the formation of fish–jellyfish associations is an important but complex process in relation to the success of fish stocks globally

The SED Machine: a robotic spectrograph for fast transient classification

Current time domain facilities are finding several hundreds of transient astronomical events a year. The discovery rate is expected to increase in the future as soon as new surveys such as the Zwicky Transient Facility (ZTF) and the Large Synoptic Sky Survey (LSST) come on line. At the present time, the rate at which transients are classified is approximately one order or magnitude lower than the discovery rate, leading to an increasing "follow-up drought". Existing telescopes with moderate aperture can help address this deficit when equipped with spectrographs optimized for spectral classification. Here, we provide an overview of the design, operations and first results of the Spectral Energy Distribution Machine (SEDM), operating on the Palomar 60-inch telescope (P60). The instrument is optimized for classification and high observing efficiency. It combines a low-resolution (R$\sim$100) integral field unit (IFU) spectrograph with "Rainbow Camera" (RC), a multi-band field acquisition camera which also serves as multi-band (ugri) photometer. The SEDM was commissioned during the operation of the intermediate Palomar Transient Factory (iPTF) and has already proved lived up to its promise. The success of the SEDM demonstrates the value of spectrographs optimized to spectral classification. Introduction of similar spectrographs on existing telescopes will help alleviate the follow-up drought and thereby accelerate the rate of discoveries.Comment: 21 pages, 20 figure

Investigation of cycling-induced microstructural degradation in silicon-based electrodes in lithium-ion batteries using X-ray nanotomography

The microstructural degradation of a composite silicon electrode at different stages in its cycle life was investigated in 3D using X-ray nano-computed tomography. A reconstructed volume of 36 μm × 27 μm × 26 μm from the composite electrode was imaged in its pristine state and after 1, 10 and 100 cycles. Particle fracturing and phase transformation was observed within the electrode with increased cycling. In addition, a distinct, lower X-ray attenuating phase was clearly resolved, which can be associated with surface film formation resulting from electrolyte breakdown and with silicon particle phase transformation. Changes in quantified microstructural properties such as phase volume fraction and particle specific surface area were tracked. Electrode performance loss is associated with loss of active silicon. These imaging results further highlight the capability of high resolution X-ray tomography to investigate the role of electrode microstructure in battery degradation and failure

60 million years of glaciation in the Transantarctic Mountains

The Antarctic continent reached its current polar location ~83 Ma and became shrouded by ice sheets ~34 Ma, coincident with dramatic global cooling at the Eocene-Oligocene boundary. However, it is not known whether the first Antarctic glaciers formed immediately prior to this or were present significantly earlier. Here we show that mountain glaciers were likely present in the Transantarctic Mountains during the Late Palaeocene (~60–56 Ma) and middle Eocene (~48–40 Ma). Temperate (warm-based) glaciers were prevalent during the Late Eocene (~40–34 Ma) and, in reduced numbers, during the Oligocene (~34–23 Ma), before larger, likely cold-based, ice masses (including ice sheets) dominated. Some temperate mountain glaciers were present during the Miocene Climatic Optimum (~15 Ma), before a widespread switch to cold-based glaciation. Our findings highlight the longevity of glaciation in Antarctica and suggest that glaciers were present even during the Early-Cenozoic greenhouse world

Nitrogenase bioelectrocatalysis: heterogeneous ammonia and hydrogen production by MoFe protein

notrogenase is the only enzyme known to catalyze the reduction of N2 to 2NH3. In vivo, the MoFe protein component of nitrogenase is exclusively reduced by the ATP-hydrolyzing Fe protein in a series of transient association/dissociation steps that are linked to the hyderolysis of two ATP for each electron transeferred. We report MoFe protein immobilized at an electrode surface, where cobaltocene (as an electron mediator that can be observed in real time at a carbon electrode) is used to reduce the MoFe protein (independent of the Fe protein and of ATP hydrolysis) and support the bioelectrocatalytic reduction of protons to dihydrogen, azide to ammonia, and nitrit to ammonia. Bulk bioelectrosynthetic N3 or NO2 reduction (50 mM) for 30 minutes yielded 70 +- 9 nmol NH3 and 234 +- 62 nmol NH3, with NO2 reduction operating at high faradaic efficiency

Inclusive quasi-elastic electron-nucleus scattering

This article presents a review of the field of inclusive quasi-elastic electron-nucleus scattering. It discusses the approach used to measure the data and includes a compilation of data available in numerical form. The theoretical approaches used to interpret the data are presented. A number of results obtained from the comparison between experiment and calculation are then reviewed. The analogies and differences to other fields of physics exploiting quasi-elastic scattering from composite systems are pointed out.Comment: Accepted for publication in Reviews of Modern Physic

Association between fish consumption, long chain omega 3 fatty acids, and risk of cerebrovascular disease: Systematic review and meta-analysis

Objective: To clarify associations of fish consumption and long chain omega 3 fatty acids with risk of cerebrovascular disease for primary and secondary prevention. Design: Systematic review and meta-analysis. Data sources: Studies published before September 2012 identified through electronic searches using Medline, Embase, BIOSIS, and Science Citation Index databases. Eligibility criteria: Prospective cohort studies and randomised controlled trials reporting on associations of fish consumption and long chain omega 3 fatty acids (based on dietary self report), omega 3 fatty acids biomarkers, or supplementations with cerebrovascular disease (defined as any fatal or non-fatal ischaemic stroke, haemorrhagic stroke, cerebrovascular accident, or transient ischaemic attack). Both primary and secondary prevention studies (comprising participants with or without cardiovascular disease at baseline) were eligible. Results: 26 prospective cohort studies and 12 randomised controlled trials with aggregate data on 794 000 non-overlapping people and 34 817 cerebrovascular outcomes were included. In cohort studies comparing categories of fish intake the pooled relative risk for cerebrovascular disease for 2-4 servings a week versus ≤1 servings a week was 0.94 (95% confidence intervals 0.90 to 0.98) and for ≥5 servings a week versus 1 serving a week was 0.88 (0.81 to 0.96). The relative risk for cerebrovascular disease comparing the top thirds of baseline long chain omega 3 fatty acids with the bottom thirds for circulating biomarkers was 1.04 (0.90 to 1.20) and for dietary exposures was 0.90 (0.80 to 1.01). In the randomised controlled trials the relative risk for cerebrovascular disease in the long chain omega 3 supplement compared with the control group in primary prevention trials was 0.98 (0.89 to 1.08) and in secondary prevention trials was 1.17 (0.99 to 1.38). For fish or omega 3 fatty acids the estimates for ischaemic and haemorrhagic cerebrovascular events were broadly similar. Evidence was lacking of heterogeneity and publication bias across studies or within subgroups. Conclusions Available observational data indicate moderate, inverse associations of fish consumption and long chain omega 3 fatty acids with cerebrovascular risk. Long chain omega 3 fatty acids measured as circulating biomarkers in observational studies or supplements in primary and secondary prevention trials were not associated with cerebrovascular disease. The beneficial effect of fish intake on cerebrovascular risk is likely to be mediated through the interplay of a wide range of nutrients abundant in fish

Effect of mechanical preconditioning on the electrical properties of knitted conductive textiles during cyclic loading

This paper presents, for the first time, the electrical response of knitted conductive fabrics to a considerable number of cycles of deformation in view of their use as wearable sensors. The changes in the electrical properties of four knitted conductive textiles, made of 20% stainless steel and 80% polyester fibers, were studied during unidirectional elongation in an Instron machine. Two tests sessions of 250 stretch–recovery cycles were conducted for each sample at two elongation rates (9.6 and 12 mm/s) and at three constant currents (1, 3 and 6 mA). The first session assessed the effects of an extended cyclic mechanical loading (preconditioning) on the electrical properties, especially on the electrical stabilization. The second session, which followed after a 5 minute interval under identical conditions, investigated whether the stabilization and repeatability of the electrical features were maintained after rest. The influence of current and elongation rate on the resistance measurements was also analyzed. In particular, the presence of a semiconducting behavior of the stainless steel fibers was proved by means of different test currents. Lastly, the article shows the time-dependence of the fabrics by means of hysteresis graphs and their non-linear behavior thanks to a time–frequency analysis. All knit patterns exhibited interesting changes in electrical properties as a result of mechanical preconditioning and extended use. For instance, the gauge factor, which indicates the sensitivity of the fabric sensor, varied considerably with the number of cycles, being up to 20 times smaller than that measured using low cycle number protocols

A New Method Comparing Snowmelt Timing with Annual Area Burned

The interactions between climate and wildland fire are complex. To better understand these interactions, we used ArcMap 10.2.2 to examine the relationships between early spring snowmelt and total annual area burned within a defined region of the Rocky Mountains of the western United States. Our research methods used Monitoring Trends in Burn Severity (MTBS) fire perimeter data and weekly snow extent provided by the Rutgers Global Snow Lab analysis of National Oceanic and Atmospheric Administration (NOAA) daily snow maps. Our results indicated a significant correlation between early spring snowmelt and total annual area burned (P = 0.0497), providing further evidence that snowmelt timing may be a driving factor for wildland fires. This project builds on the findings of previous studies and provides a novel method for making general predictions about the upcoming fire season months in advance, using freely available remotely sensed data in real time. Further research should apply our model to a broader geographic area, and incorporate higher resolution snowmelt timing data