Nuclear Compton scattering from 12C

Nuclear Compton scattering — the elastic scattering of photons — from 12C has been studied at the Tagged-Photon Facility at MAX IV in Lund, Sweden. The differential cross section for the reaction was determined at laboratory angles of 60° and 120° in the energy range 65-95 MeV. The cross section for nuclear Compton scattering is related to the electric and magnetic polarisabilities of the proton and the neutron. The polarisabilities are fundamental structure constants that describe how nucleons are affected by an external electromagnetic field. The determination of the electric and magnetic polarisabilities of the neutron through measurements of the deuterium Compton scattering cross section is the goal of a recent large scale experimental effort spanning almost a decade at the Tagged-Photon Facility at MAX IV. The purpose of this experiment was twofold: to verify the procedure for normalisation of Compton scattering data by investigating 12C and comparing to a well-established and comprehensive existing body of data, and to determine whether the electric and magnetic polarisabilities of free nucleons are affected when they are bound inside a nucleus

Abundance and distribution of planktonic Archaea and Bacteria in the waters west of the Antarctic Peninsula

Polyribonucleotide probes targeting planktonic archaeal (Group I and II) and bacterial rRNA revealed that Archaea comprised a significant fraction of total prokaryote cell abundance in the marine waters west of the Antarctic Peninsula. Determinations of Archaea and Bacteria cell abundances were made during two research cruises to the Palmer Long‐Term Ecological Research region during the austral winter and summer of 1999. During the austral summer, surface water abundances of Group I (GI) Archaea were generally low, averaging 4.7 x 103 cells ml−1 and accounting for 1% of the total picoplankton assemblage. The abundance of GI Archaea increased significantly with depth, averaging 2.1 X 104 cells ml−1 and comprising 9–39% of the total picoplankton abundance in the meso‐ (150–1,000 m) and bathypelagic (1,000–3,500 m) circumpolar deep water (CDW). Relative to summertime distributions, GI cells were more evenly distributed throughout the water column during the winter, averaging 10% of the picoplankton in the surface waters and 13% in the CDW. Surface water GI abundance increased 44% between the summer and winter, coincident with a fivefold decrease in GI abundance in the deeper waters. The abundance of Group II (GII) Archaea was persistently \u3c2% of the total picoplankton throughout the water column in both summer and winter. Bacterial abundance was greatest in the upper water column (0–100 m) during the summer, averaging 3.9 x 105 cells ml−1 and comprised 89% of the total picoplankton assemblage. Generally, GI Archaea varied seasonally in the deeper waters, whereas bacterial abundance varied more in the upper waters. The observed variability in bacterial and archaeal abundance suggests that these two groups of marine picoplankton are dynamic components of Southern Ocean microbial food webs

Proton-and Neutron-Induced Single-Event Upsets in FPGAs for the PANDA Experiment

Single-event upsets (SEUs) affecting the configuration memory of a 28-nm field-programmable gate array (FPGA) have been studied through experiments and Monte Carlo modeling. This FPGA will be used in the front-end electronics of the electromagnetic calorimeter in PANDA (Antiproton Annihilation at Darmstadt), an upcoming hadron-physics experiment. Results from proton and neutron irradiations of the FPGA are presented and shown to be in agreement with previous experimental results. To estimate the mean time between SEUs during operation of PANDA, a Geant4-based Monte Carlo model of the phenomenon has been used. This model describes the energy deposition by particles in a silicon volume, the subsequent drift and diffusion of charges in the FPGA memory cell, and the eventual collection of charges in the sensitive regions of the cell. The values of the two free parameters of the model, the sensitive volume side d = 87 nm and the critical charge Qcrit = 0.23 fC, were determined by fitting the model to the experimental data. The results of the model agree well with both the proton and neutron data and are also shown to correctly predict the cross sections for upsets induced by other particles. The model-predicted energy dependence of the cross section for neutron-induced upsets has been used to estimate the rate of SEUs during initial operation of PANDA. At a luminosity of 1&amp;cdot; 1031 cm-2s-1, the predicted mean time between upsets (MTBU) is between 120 and 170 h per FPGA, depending on the beam momentum.</p

Measurements and simulations of single-event upsets in a 28-nm FPGA

Single-event upsets in the configuration memory of the 28-nm Xilinx Kintex-7 FPGA, used in the PANDA electromagnetic calorimeter, have been studied. Results from neutron and proton irradiations at energies up to 184 MeV are presented and compared with previous experimental results. In order to gain information about the energy-dependence of the single-event upset cross section, a GEANT4-based Monte Carlo simulation of upset mechanisms in nanometric silicon volumes has been developed. The results from this model are shown to agree with the experimental data for both neutrons and protons. Knowledge about the energy dependence of the cross section and of the particle flux at the location of the front-end modules in PANDA enables better estimates of the mean time between failures in the electromagnetic calorimeter. At PANDA, a total neutron flux of 1·102 cm− 2 s− 1 at the location of the front-end modules is expected at the lowest antipro-ton beam momentum and a luminosity of 1·1031 cm− 2 s− 1, leading to a predicted Mean Time Between Failures of 47±10 hours per FPGA in the electromagnetic calorimeter

Discovering the RNA-binding proteome of plant leaves with an improved RNA interactome capture method

RNA-binding proteins (RBPs) play a crucial role in regulating RNA function and fate. However, the full complement of RBPs has only recently begun to be uncovered through proteome-wide approaches such as RNA interactome capture (RIC). RIC has been applied to various cell lines and organisms, including plants, greatly expanding the repertoire of RBPs. However, several technical challenges have limited the efficacy of RIC when applied to plant tissues. Here, we report an improved version of RIC that overcomes the difficulties imposed by leaf tissue. Using this improved RIC method in Arabidopsis leaves, we identified 717 RBPs, generating a deep RNA-binding proteome for leaf tissues. While 75% of these RBPs can be linked to RNA biology, the remaining 25% were previously not known to interact with RNA. Interestingly, we observed that a large number of proteins related to photosynthesis associate with RNA in vivo, including proteins from the four major photosynthetic supercomplexes. As has previously been reported for mammals, a large proportion of leaf RBPs lack known RNA-binding domains, suggesting unconventional modes of RNA binding. We anticipate that this improved RIC method will provide critical insights into RNA metabolism in plants, including how cellular RBPs respond to environmental, physiological and pathological cues

Bryophytes of Europe Traits (BET) dataset: a fundamental tool for ecological studies

Bryophytes are a diverse group of organisms with unique properties, yet they are severely underrepresented in plant trait databases. Building on the recently published European Red List of bryophytes and previous trait compilations, we present the Bryophytes of Europe Traits (BET) data set, including biological traits such as those related to life history, growth habit, sexual and vegetative reproduction; ecological traits such as indicator values, substrate and habitat; and bioclimatic variables based on the species' European range. The data set includes values for 65 traits and 25 bio-climatic variables, containing more than 135,000 trait values with a completeness of 82.7% on average. The data set will enable future studies in bryophyte biology, ecology and conservation, and may help to answer fundamental questions in bryology.info:eu-repo/semantics/publishedVersio

Learning about pain from others: an observational learning account

Although direct experience and verbal instruction are important sources in the development of pain-related beliefs and behaviors, accumulating evidence indicates that observation of others in pain may be equally as important. Taking a contemporary view on learning as a starting point, we discuss available evidence on observational learning in the context of pain, highlight its importance for both development and management of chronic pain problems, and discuss potential moderators of observational learning effects. We argue that the capacity to understand and appreciate the experience of another person is fundamental to observational learning, including use of this information to establish the association between pain and antecedent or consequent stimuli. A main objective of this paper is to stimulate research on the role of learning about pain from others. Several lines for further research, including clinical applications, are delineated. Perspective: Based upon a contemporary view on learning, this focus article delineates how pain-related beliefs and behaviors may be learnt by observing others. It is discussed how further research on the acquisition of pain-related beliefs/behaviors might further our understanding of pain and disability. (PsycINFO Database Record (c) 2011 APA, all rights reserved) (journal abstract

Overview of the coordinated ground-based observations of Titan during the Huygens mission

Coordinated ground-based observations of Titan were performed around or during the Huygens atmospheric probe mission at Titan on 14 January 2005, connecting the momentary in situ observations by the probe with the synoptic coverage provided by continuing ground-based programs. These observations consisted of three different categories: (1) radio telescope tracking of the Huygens signal at 2040 MHz, (2) observations of the atmosphere and surface of Titan, and (3) attempts to observe radiation emitted during the Huygens Probe entry into Titan's atmosphere. The Probe radio signal was successfully acquired by a network of terrestrial telescopes, recovering a vertical profile of wind speed in Titan's atmosphere from 140 km altitude down to the surface. Ground-based observations brought new information on atmosphere and surface properties of the largest Satumian moon. No positive detection of phenomena associated with the Probe entry was reported. This paper reviews all these measurements and highlights the achieved results. The ground-based observations, both radio and optical, are of fundamental imnortance for the interpretatinn of results from the Huygens mission

Species-Area Relationships Are Controlled by Species Traits

The species-area relationship (SAR) is one of the most thoroughly investigated empirical relationships in ecology. Two theories have been proposed to explain SARs: classical island biogeography theory and niche theory. Classical island biogeography theory considers the processes of persistence, extinction, and colonization, whereas niche theory focuses on species requirements, such as habitat and resource use. Recent studies have called for the unification of these two theories to better explain the underlying mechanisms that generates SARs. In this context, species traits that can be related to each theory seem promising. Here we analyzed the SARs of butterfly and moth assemblages on islands differing in size and isolation. We tested whether species traits modify the SAR and the response to isolation. In addition to the expected overall effects on the area, traits related to each of the two theories increased the model fit, from 69% up to 90%. Steeper slopes have been shown to have a particularly higher sensitivity to area, which was indicated by species with restricted range (slope  = 0.82), narrow dietary niche (slope  = 0.59), low abundance (slope  = 0.52), and low reproductive potential (slope  = 0.51). We concluded that considering species traits by analyzing SARs yields considerable potential for unifying island biogeography theory and niche theory, and that the systematic and predictable effects observed when considering traits can help to guide conservation and management actions

Borders, Fences, and Limits—Protecting Austria From Refugees:Metadiscursive Negotiation of Meaning in the Current Refugee Crisis

The so-called refugee crisis presents a field of discursive struggle over meanings in politics. In Austria, mediatized politics in 2015 and 2016 was dominated by metadiscursive negotiation of terminology related to building a border fence and setting a maximum limit on refugees. Both issues raised serious ideological and legal concerns and were thus largely euphemized; as responses to ever-increasing pressure from the political right, however, they were also intended as signals to voters. This article presents a discourse-historical study of the normalization of restrictive policies in the theoretical framework of border and body politics, otherness, and mediatization