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Investigations into the existence of life in other parts of the cosmos find strong parallels with studies of the origin and evolution of life on our own planet. In this way, astrobiology and paleobiology are married by their common interest in disentangling the interconnections between life and the surrounding environment. In this way, a cross-point of both sciences is paleometry, which involves a myriad of imaging and geochemical techniques, usually non-destructive, applied to the investigation of the fossil record. In the last decades, paleometry has benefited from an unprecedented technological improvement, thus solving old questions and raising new ones. This advance has been paralleled by conceptual approaches and discoveries fuelled by technological evolution in astrobiological research. In this context, we present some new data and review recent advances on the employment of paleometry to investigations on paleobiology and astrobiology in Brazil in areas such biosignatures in Ediacaran microbial mats, biogenicity tests on enigmatic Ediacaran structures, research on Ediacaran metazoan biomineralization, fossil preservation in Cretaceous insects and fish, and finally the experimental study on the decay of fish to test the effect of distinct types of sediment on soft-tissue preservation, as well as the effects of early diagenesis on fish bone preservation.
This paper presents a fully-integrated direct-conversion fundamentally-operated mixer-first quadrature receiver module with a tunable LO in the 219–266 GHz band. It has been implemented in a 0.13-μm SiGe heterojunction bipolar transistor technology. It includes an on-chip LO path driven externally from the printed circuit board (PCB) connector level at 13.6–16.7 GHz. A hybrid coupler generates the quadrature LO signal, which drives a pair of double-balanced fundamentally-operated down-conversion mixers, whose RF ports are connected to a wideband lens-integrated on-chip ring antenna. The chip-on-lens assembly is placed in the recess of a high-speed PCB and wire-bonded. To compensate the inductive behavior of the wire-bond interconnection between the chip and the PCB at the high-speed IF outputs, an on-board 8-section step-impedance low-pass filter has been implemented. The module shows a 47 GHz 3-dB radio frequency/local oscillator operation bandwidth (BW), a peak conversion gain of 7.8 dB, a single-side-band noise figure of 11.3 dB, and a 3-dB IF BW of 13 GHz. The in-phase and quadrature amplitude imbalance stays below 1.58 dB for the 210–280 GHz band. The down-conversion and the baseband stages consume together 75.5 mW, while the LO path 378 mW. The maximum data-rate achieved with this receiver in combination with the transmitter presented in [1–3] is 60 Gbps for quadrature phase shift keying modulation.
Major depression and anxiety disorders are known to negatively influence cognitive performance. Moreover, there is evidence for greater cognitive decline in older adults with generalized anxiety disorder. Except for clinical studies, complex executive planning functions and subclinical levels of anxiety have not been examined in a population-based sample with a broad age range.
Methods
Planning performance was assessed using the Tower of London task in a population-based sample of 4240 participants aged 40–80 years from the Gutenberg Health Study (GHS) and related to self-reported anxiety and depression by means of multiple linear regression analysis.
Results
Higher anxiety ratings were associated with lower planning performance (β = −0.20; p < 0.0001) independent of age (β = 0.03; p = 0.47). When directly comparing the predictive value of depression and anxiety on cognition, only anxiety attained significance (β = −0.19; p = 0.0047), whereas depression did not (β = −0.01; p = 0.71).
Conclusions
Subclinical levels of anxiety but not of depression showed negative associations with cognitive functioning independent of age. Our results demonstrate that associations observed in clinical groups might differ from those in population-based samples, also with regard to the trajectory across the life span. Further studies are needed to uncover causal interrelations of anxiety and cognition, which have been proposed in the literature, in order to develop interventions aimed at reducing this negative affective state and to improve executive functioning.
Animal health surveillance enables the detection and control of animal diseases including zoonoses. Under the EU-FP7 project RISKSUR, a survey was conducted in 11 EU Member States and Switzerland to describe active surveillance components in 2011 managed by the public or private sector and identify gaps and opportunities. Information was collected about hazard, target population, geographical focus, legal obligation, management, surveillance design, risk-based sampling, and multi-hazard surveillance. Two countries were excluded due to incompleteness of data. Most of the 664 components targeted cattle (26·7%), pigs (17·5%) or poultry (16·0%). The most common surveillance objectives were demonstrating freedom from disease (43·8%) and case detection (26·8%). Over half of components applied risk-based sampling (57·1%), but mainly focused on a single population stratum (targeted risk-based) rather than differentiating between risk levels of different strata (stratified risk-based). About a third of components were multi-hazard (37·3%). Both risk-based sampling and multi-hazard surveillance were used more frequently in privately funded components. The study identified several gaps (e.g. lack of systematic documentation, inconsistent application of terminology) and opportunities (e.g. stratified risk-based sampling). The greater flexibility provided by the new EU Animal Health Law means that systematic evaluation of surveillance alternatives will be required to optimize cost-effectiveness.
Cover crop-based reduced tillage (CCBRT) has achieved positive impacts in organic row crop systems, contributing to the conservation of soil resources and the facilitation of weed management. This technique, which uses cover crop residues as mulches to suppress weeds, has shown more variable success in organic vegetable production systems. This experiment examined CCBRT for small-scale organic vegetable production in the upper Midwestern USA, specifically evaluating weed suppression, labor inputs and crop yields. Cereal rye (Secale cereale L.) and winter wheat (Triticum aestivum L.) were fall-sown in 2012 and 2013 in a strip-plot design, including control treatments with no cover crop and spring-applied oat straw mulch. Cover crop plots were strip-tilled in mid-April to establish a planting zone, with cover crops terminated in late May at anthesis with a hand-tractor mounted sickle-bar mower. Bell peppers (Capsicum annuum L. var. ‘Revolution’), snap beans (Phaseolus vulgaris L. var. ‘Tavera’), and potatoes (Solanum tuberosum L. var. ‘Red La Soda’) were hand-planted either as transplants or seed in each treatment immediately following cover crop termination. During each summer growing season, weeds were completely eliminated from each plot by hand approximately every 10–14 days, with time for manual weeding recorded for each treatment. Vegetable crop yields and quality were measured at harvest during 2013 and 2014. Cereal rye and winter wheat produced similar biomass at the time of termination. Greater weed biomass was collected in the wheat treatment as compared with the cereal rye, increasing the in-season labor required for manual weeding. Bean yields were decreased in the all CCBRT treatments compared with control treatments in both years of the study. Pepper yields did not differ in CCBRT treatments as compared with the control in both 2012 and 2013, although the CCBRT treatments did yield lower marketable peppers compared with the straw mulch plots. Potato tuber yields were not different in the CCBRT treatments as compared with the control in 2012, but were lower in 2013. These data indicate that, if CCBRT is to be more widely adopted in small-scale vegetable production, further optimization of the system must be achieved to ensure consistent and adequate weed suppression while maintaining crop yield and quality.
A 240-GHz monostatic circular polarized SiGe frequency-modulated continuous wave radar system based on a transceiver chip with a single on-chip antenna is presented. The radar transceiver front-end is implemented in a low-cost 0.13 µm SiGe HBT technology version with cut-off frequencies fT/fmax of 300/450 GHz. The transmit block comprises a wideband ×16 frequency multiplier chain, a three-stage PA, while the receive block consists of a low-noise amplifier, a fundamental quadrature down-conversion mixer, and a three-stage PA to drive the mixer. A differential branch-line coupler and a differential dual-polarized on-chip antenna are added on-chip to realize a fully integrated radar transceiver. All building blocks are implemented fully differential. The use of a single antenna in the circular polarized radar transceiver leads to compact size and high sensitivity. The measured peak-radiated power from the Si-lens equipped radar module is +11 dBm (equivalent isotropically radiated power) at 246 GHz and noise figure is 21 dB. The characterization bandwidth of the radar transceiver is 60 GHz around the center frequency of 240 GHz, and the simulated Tx-to-Rx leakage is below −20 dB from 230 to 260 GHz. After system calibration the resolution of the system to distinguish between two targets at different distance of 3.65 mm is achieved, which is only 21% above the theoretical limit.
In this globalized world, the spread of new, exotic and re-emerging diseases has become one of the most important threats to animal production and public health. This systematic review analyses conventional and novel early detection methods applied to surveillance. In all, 125 scientific documents were considered for this study. Exotic (n = 49) and re-emerging (n = 27) diseases constituted the most frequently represented health threats. In addition, the majority of studies were related to zoonoses (n = 66). The approaches found in the review could be divided in surveillance modalities, both active (n = 23) and passive (n = 5); and tools and methodologies that support surveillance activities (n = 57). Combinations of surveillance modalities and tools (n = 40) were also found. Risk-based approaches were very common (n = 60), especially in the papers describing tools and methodologies (n = 50). The main applications, benefits and limitations of each approach were extracted from the papers. This information will be very useful for informing the development of tools to facilitate the design of cost-effective surveillance strategies. Thus, the current literature review provides key information about the advantages, disadvantages, limitations and potential application of methodologies for the early detection of new, exotic and re-emerging diseases.
Declines in Old World vulture populations have been linked to anthropogenic pressures. To assess these threats, the social dimensions of vulture conservation must be explored. Prior research in Africa focused on commercial farmers’ perceptions of vultures and identified that small stock farmers used poison more than large stock farmers to deter livestock predators. However, the vulnerable Cape Vulture Gyps coprotheres breeds throughout communal farmland in the Eastern Cape Province, South Africa. Consequently, community interviews were conducted within the foraging range of the Msikaba Cape Vulture colony, separating regions according to the amount of transformed land. Residents in the least transformed land region perceived the smallest reductions in livestock ownership over the past ten years, while residents of the moderately transformed region perceived the greatest reductions in livestock ownership. Livestock carcasses were reported to be available for vultures at ‘informal vulture restaurants’. Arrangement of livestock carcasses was found to be independent of land use; however type of carcass consumed varied. None of the respondents stated they used poison to eliminate livestock predators. More respondents cited illegal poaching of vultures for traditional medicine as a threat, although the majority stated that vultures benefited the community.
Laser processing of thin-film silicon is a promising approach for the realization of polycrystalline silicon for large area electronics and solar cell applications. In this study we investigate the material modification of amorphous hydrogenated silicon (a-Si:H) with different hydrogen content (30%, 13% and <1%) by means of femtosecond (fs) laser pulses. Depending on the peak fluence applied, hydrogen diffusion/effusion, layer crystallization or material ablation can be achieved. Despite the low absorption coefficient of a-Si:H at the center wavelength of an amplified Titanium Sapphire laser at 790 nm a high local energy deposition close to the surface of the a-Si:H layer is observed, which can be attributed to a nonlinear absorption process.
We have performed large-scale nucleosynthesis calculations within the high-entropy-wind (HEW) scenario of Type II supernovae. The primary aim was to constrain the conditions for the production of the classical ‘p-only’ isotopes of the light trans-Fe elements. We find, however, that for electron fractions in the range 0.458 ≤ Ye ≤ 0.478, sizeable abundances of p-, s- and r-process nuclei between 64Zn and 98Ru are coproduced in the HEW at low entropies (S ≤ 100) by a primary charged-particle process after an α-rich freezeout. With the above Ye–S correlation, most of the predicted isotopic abundance ratios within a given element, e.g. 64Zn(p)/70Zn(r) or 92Mo(p)/94Mo(p), as well as of neighboring elements, e.g. 70Ge(s + p)/74Se(p) or 74Se(p)/78Kr(p) agree with the observed Solar-System ratios. Taking the Mo isotopic chain as a particularly challenging example, we show that our HEW model can account for the production of all 7 stable isotopes, from ‘p-only’ 92Mo, via ‘s-only’ 96Mo up to ‘r-only’ 100Mo. Furthermore, our model is able to reproduce the isotopic composition of Mo in presolar SiC X-grains.
Traumatized individuals and particularly post-traumatic stress disorder (PTSD) patients are characterized by memory disturbances that suggest altered memory control. The present study investigated the issue using an item method, directed forgetting (DF) paradigm in 51 civil war victims in Uganda. All participants had been exposed to severe traumatic stress and 26 additionally suffered from PTSD.
Method
In an item cued, DF paradigm photographs were presented, each followed by an instruction to either remember or forget it. A recognition test for all initially presented photographs and thematically similar distracters followed. DF patterns were compared between the non-PTSD and the PTSD groups. Post-experimental ratings of picture valence and arousal were collected and correlated with DF.
Results
Results revealed DF, that is, reduced recognition for ‘to-be-forgotten’ items in the non-PTSD but not in the PTSD group. Moreover, in the non-PTSD, but not in the PTSD group, false alarms were reduced for ‘to-be-remembered’ items. Finally, DF was reduced in those participants who rated the pictures as more arousing, the PTSD group giving, on average, higher arousal ratings.
Conclusions
Data indicate that DF is reduced in PTSD and that the reduction is related to stimulus arousal. Furthermore, individuals with PTSD are characterized by a more global encoding style than individuals without PTSD, reflected in a higher false alarm rate. In sum, traumatized individuals with (but not without) PTSD are impaired in their ability to selectively control episodic memory encoding. This impairment may contribute to clinical features of the disorder such as intrusions and flashbacks.
Fruit and seed consumers can both positively and negatively affect plant recruitment through seed dispersion and seed predation, respectively. In turn, fruits influence the abundance and distribution of consumers sustained by local plant assemblages. These interactions are key processes in plant recruitment and the dynamics of tropical forests, where most plants depend on dispersal by frugivorous animals (Corlett 1998). An understanding of these interactions and the functional role of particular seed-dispersing animals is increasingly important nowadays, given that human impact on tropical forest ecosystems may negatively impact seed dispersal and forest regeneration in both natural and human-altered forests (Wright et al. 2000).
We report on a dedicated effort to identify and study metal-poor stars that are strongly enhanced in r-process elements ($\mbox{[r/Fe]}>+1.0$dex; hereafter r-II stars), the Hamburg/ESO R-process Enhanced Star survey (HERES). In a sample of 253 confirmed metal-poor stars for which “snapshot” spectra ($R\sim 20,000$; $S/N \sim 50/1$ per pixel) were obtained with VLT/UVES, and abundances were determined in an automated fashion using the methods of Barklem et al. (2005), we identified eight new r-II stars. They are now being studied in detail by means of higher resolution and S/N spectroscopy. The new r-II stars have metallicities in the range $-3.2<\mbox{[Fe/H]}<-2.6$. Future searches for r-II stars should therefore focus on stars in this [Fe/H] range. Moderately r-process enhanced stars (i.e., $+0.3\,\mbox{dex}<\mbox{[r/Fe]}<+1.0\,\mbox{dex}$; r-I stars) were found at metallicities as high as $\mbox{[Fe/H]} = -1.5$. The [Fe/H] ranges in which r-I and r-II stars can be found may provide an important constraint for the identification of the site(s) of the r-process(es).
The smoothing mechanism, that is due to the thermal
conductivity in the laser plasma generated by a double
pulse, is examined. Plasma preformed by a second harmonics
prepulse serves as a low density gradient plasma for impacting
the main pulse, the frequency of which was tripled for
improving the laser-target coupling. The effect of the
preformed plasma on the thermal smoothing of the heating
pulse, which was split to create two foci on the target
surface, was explored by varying the time delay between
the prepulse and the main pulse. The smoothing effect was
monitored by a pair of pinhole cameras: one viewing side-on
and the other one placed at the rear side of the target.
Spatially resolved X-ray emission spectra were recorded
to determine the density and temperature distributions
in the plasma. The maximum smoothing effect was observed
for the time delay t = 0.4–0.7 ns.
The Schistosoma mansoni protein, SPRM1lc, is a light chain member of a new family of heterodimeric amino acid
permeases. These proteins require covalent association with a type II glycoprotein (like h4F2hc) for functional surface
localization when expressed in Xenopus oocytes. We previously reported that, when co-expressed with h4F2hc, the
transport properties of SPRM1lc resemble system y and y+ while its human homologue, E16, functions as an L-type
permease. Here we extend the functional characterization of SPRM1lc in oocytes and show by competitor studies that its
amino acid transport capacity is similar to that of whole adult schistosomes. We demonstrate by Northern and Western
analysis that SPRM1lc is expressed within both larval and adult schistosomes. In all stages, SPRM1lc is associated into
a high molecular weight complex that can be disrupted by reducing agents, consistent with the hypothesis that a significant
fraction of the endogenous SPRM1lc is linked by a disulphide bond to an uncharacterized schistosome amino acid
transporter heavy chain. Immunofluorescence localization detects SPRM1lc in miracidia, daughter sporocysts and adult
worms. Confocal microscopy demonstrates that SPRM1lc is found in the apical membrane of the syncytial, double-lipid
bilayer tegument which surrounds adult worms. Aqueous biotinylation studies on living worms show that SPRM1lc is
exposed on the host-interactive surface of this tegumental membrane. Host exposed, functionally important surface
proteins such as SPRM1lc could form the basis of an effective schistosomiasis vaccine. These studies are the first to
describe a helminth amino acid transporter, and the first to characterize an invertebrate heterodimeric amino acid
transporter.
By
F.-K. Thielemann, Departement für Physik und Astronomie, Universität Basel, CH–4056 Basel, Switzerland, institute for Theoretical Physics, University of California, Santa Barbara, CA 93106–4030,
T. Rauscher, Departement für Physik und Astronomie, Universität Basel, CH–4056 Basel, Switzerland,
C. Freiburghaus, Departement für Physik und Astronomie, Universität Basel, CH–4056 Basel, Switzerland, institute for Theoretical Physics, University of California, Santa Barbara, CA 93106–4030,
K. Nomoto, Department of Astronomy and Research Center for the Early Universe, University of Tokyo, Tokyo 113, Japan, institute for Theoretical Physics, University of California, Santa Barbara, CA 93106–4030,
M. Hashimoto, Department of Physics, Faculty of Science, Kyushu University, Pukuoka 810, Japan,
B. Pfeiffer, Institut für Kernchemie, Universität Mainz, D–55128 Mainz, Germany,
K.-L. Kratz, Institut für Kernchemie, Universität Mainz, D–55128 Mainz, Germany
Edited by
Jorge G. Hirsch, Center of Research and Advanced Studies, National Polytechnic Institute, Mexico City,Danny Page, Universidad Nacional Autónoma de México
This review concentrates on nucleosynthesis processes in general and their applications to massive stars and supernovae. A brief initial introduction is given to the physics in astrophysical plasmas which governs composition changes. We present the basic equations for thermonuclear reaction rates and nuclear reaction networks. The required nuclear physics input for reaction rates is discussed, i.e. cross sections for nuclear reactions, photodisintegrations, electron and positron captures, neutrino captures, inelastic neutrino scattering, and beta–decay half–lives. We examine especially the present state of uncertainties in predicting thermonuclear reaction rates, while the status of experiments is discussed by others in this volume (see M. Wiescher). It follows a brief review of hydrostatic burning stages in stellar evolution before discussing the fate of massive stars, i.e. the nucleosynthesis in type II supernova explosions (SNe II). Except for SNe la, which are explained by exploding white dwarfs in binary stellar systems (which will not be discussed here), all other supernova types seem to be linked to the gravitational collapse of massive stars (M>8M⊙) at the end of their hydrostatic evolution. SN1987A, the first type II supernova for which the progenitor star was known, is used as an example for nucleosynthesis calculations. Finally, we discuss the production of heavy elements in the r–process up to Th and U and its possible connection to supernovae.
The ZZ Ceti stars form a class of variable white dwarfs: the hydrogen dominated atmosphere ones, which do pulsate in an instability strip in the effective temperature range 13000K-11500K. We know 22 such ZZ Ceti white dwarfs. Their variations are caused by nonradial g-mode pulsations with periods are in the range 100-1000 seconds.
A subsample of the ZZ Ceti stars shows amplitude variations on time scales of the order of one month. These variations could be driven by nonlinear phenomena.