Gas tungsten arc welding in a microgravity environment: Work done on GAS payload G-169

GAS payload G-169 is discussed. G-169 contains a computer-controlled Gas Tungsten Arc Welder. The equipment design, problem analysis, and problem solutions are presented. Analysis of data gathered from other microgravity arc welding and terrestrial Gas Tungsten Arc Welding (GTAW) experiments are discussed in relation to the predicted results for the GTAW to be performed in microgravity with payload G-169

Nuclear spectroscopy of Ta181

The nuclear levels of Ta181 were investigated by a study of the β decay of Hf181 and the electron capture decay of W181. Evidence for weak M-shell conversion lines of an ∼6-kev transition in the Hf181 was found with a β spectrometer. An investigation of the W181 decay with this instrument revealed strong M-shell conversion lines corresponding to a 6.25±0.3-kev transition. With the aid of additional evidence, the conclusion is made that the 476-kev transition in the Hf181 decay occurs between the 482-kev level and a new level at 6 kev. On using an argon proportional counter, a 6-kev γ ray was also found in the W181 decay. The conversion coefficient of this transition was determined to be αT=44±7. This conversion coefficient and the M-subshell conversion ratios indicate that the 6-kev transition is of E1 multipolarity. The 6-kev level is assigned as the 9/2- [514] Nilsson intrinsic state. It is also concluded that the previously reported 152-kev transition in the W181 decay occurs between a new 11/2- (K=9/2-) rotational level at 158 kev and the 6-kev level. From a measurement of the tantalum L/K x-ray intensity ratio, the W181 decay energy is found to be 176-22+44 kev. The branchings of this decay to the various Ta181 levels are as follows: 158 kev (0.11%), 136 kev (0.067%), 6.25 kev (∼35%), and ground state (∼65%). All findings and proposals are consistent with predictions of the unified model of the nucleus

TRY plant trait database – enhanced coverage and open access

Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Lessons from the Past: Sponges and the Geological Record

Sponges have been a major part of marine ecosystems, in both shallow and deep water, from the time of the earliest animal communities. The great shifts in climate that have occurred over the past 541 million years have affected all organisms, including sponges. Although patchy knowledge of the sponge fossil record hinders recognition of trends, some general patterns are apparent. Shallow-water siliceous sponges were severely affected by glacial intervals, whereas deeper-water siliceous sponges appear to have flourished during these times. Some groups of hypercalcified sponges (such as stromatoporoids) were abundant during times of global warming and high sea level, but other groups (archaeocyathans and sphinctozoans) had their acme during times of low sea level and relatively cool climate. Overall, sponge diversity appears to have been controlled more by sea level than by climate: large-scale sponge biotas occurred at times of high sea level, when there were large areas of shallow sea.Fil: Muir, Lucy. National Museum Wales; Reino UnidoFil: Botting, Joseph P.. National Museum Wales; Reino Unido. Nanjing Institute Of Geology And Palaeontology; ChinaFil: Beresi, Matilde Sylvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin

Modulation of hippocampus-dependent learning and synaptic plasticity by nicotine

A long-standing relationship between nicotinic acetylcholine receptors (nAChRs) and cognition exists. Drugs that act at nAChRs can have cognitive-enhancing effects and diseases that disrupt cognition such as Alzheimer's disease and schizophrenia are associated with altered nAChR function. Specifically, hippocampus-dependent learning is particularly sensitive to the effects of nicotine. However, the effects of nicotine on hippocampus-dependent learning vary not only with the doses of nicotine used and whether nicotine is administered acutely, chronically, or withdrawn after chronic nicotine treatment but also vary across different hippocampus-dependent tasks such as the Morris water maze, the radial arm maze, and contextual fear conditioning. In addition, nicotine has variable effects across different types of hippocampal long-term potentiation (LTP). Because different types of hippocampus-dependent learning and LTP involve different neural and molecular substrates, comparing the effects of nicotine across these paradigms can yield insights into the mechanisms that may underlie the effects of nicotine on learning and memory and aid in understanding the variable effects of nicotine on cognitive processes. This review compares and contrasts the effects of nicotine on hippocampus-dependent learning and LTP and briefly discusses how the effects of nicotine on learning could contribute to nicotine addictio

Genomic epidemiology of SARS-CoV-2 in a university outbreak setting and implications for public health planning

AbstractWhole genome sequencing of SARS-CoV-2 has occurred at an unprecedented scale, and can be exploited for characterising outbreak risks at the fine-scale needed to inform control strategies. One setting at continued risk of COVID-19 outbreaks are higher education institutions, associated with student movements at the start of term, close living conditions within residential halls, and high social contact rates. Here we analysed SARS-CoV-2 whole genome sequences in combination with epidemiological data to investigate a large cluster of student cases associated with University of Glasgow accommodation in autumn 2020, Scotland. We identified 519 student cases of SARS-CoV-2 infection associated with this large cluster through contact tracing data, with 30% sequencing coverage for further analysis. We estimated at least 11 independent introductions of SARS-CoV-2 into the student population, with four comprising the majority of detected cases and consistent with separate outbreaks. These four outbreaks were curtailed within a week following implementation of control measures. The impact of student infections on the local community was short-term despite an underlying increase in community infections. Our study highlights the need for context-specific information in the formation of public health policy for higher educational settings.</jats:p