In many regions, climatic drying is shortening hydroperiods and freshwater biodiversity is declining. Aquatic species that lack a desiccation‐resistant life stage are predicted to have the least ...ability to persist in drying climates, yet such species may occur in intermittent waterbodies. We examined the distribution of two crustacean species that lack desiccation‐resistant life stages: the isopod Paramphisopus palustris and amphipod Chiltoniidae sp.nov., before and after the commencement of severe climatic drying in Swan Coastal Plain wetlands, south‐western Australia. Historical distribution data for these species were obtained from studies of the same set of wetlands in 1989–1990.
We determined whether population or body size differed between hydrological regimes (perennial, semi‐perennial, seasonal) between 1989–1990 and 2018–2019 for both species. Amphipods, isopods and environmental variables were sampled from 42 wetlands in 2018–2019. Thirty‐three wetlands (22 perennial, 11 seasonal) persisted with the same hydrological regime in both time periods and eight wetlands that were perennial in 1989–1990 had shifted to a drier hydrological regime (four became semi‐perennial, four became seasonal) by 2018–2019.
Drying wetland hydrological regimes did not correspond to more limited spatial distributions for either species. Hydrological regime had no effect on amphipod counts, although abundances were lower in 2018–2019 than 1989–1990. In 2018–2019, male amphipods were larger than females in seasonal wetlands, but sexes were the same size in perennial wetlands and females were larger than males in semi‐perennial wetlands. Furthermore, amphipods of both sexes were considerably smaller in semi‐perennial than seasonal or perennial wetlands.
Isopod distributions differed between the two sampling periods, with populations primarily lost from wetlands that remained perennial. This unexpected result was likely caused by prolonged periods of high summer–autumn water temperatures and stratification in shallow perennial wetlands that caused anoxia in bottom waters and made surface waters excessively hot for isopods. By contrast, drying seasonal wetlands seemingly offered suitable habitat in summer–autumn. Mean isopod head and body length did not differ between hydrological regimes or sexes, but became smaller between 1989–1990 and 2018–2019 (15 mm average body length in 1989 vs. 8.3 mm in 2018–2019; 17 mm maximum size in 1989–1990 vs. 13.2 mm in 2018–2019).
The absence of population losses associated with drying hydrological regimes indicates that the current level of drying is within the tolerance range of both species. However, increased temperatures may be causing body size (and possibly fecundity) to decline for isopods.
As global warming continues to shorten wetland hydroperiods in many regions, numerous species will struggle to complete their life cycles, leading to extirpation. Our findings suggest that climate change may also cause conditions in perennial wetlands to exceed the tolerances of species that lack desiccation resistance traits. This emphasises the need to better understand both environmental and habitat changes along the drying trajectory in wetlands and the fundamental life‐history and physiological traits that enable the survival of aquatic invertebrates that lack desiccation resistance. This includes not only species responses to drying, but also responses to other stressors (e.g., prolonged stratification) caused by global warming.
Abstract
Isopods play many important roles within freshwater ecosystems (including as shredders, prey, and detritivores), yet we know little about their responses to disturbance or whether they vary ...among populations. In a region undergoing severe climatic drying that is changing hydrological regimes in wetlands, we compared responses to drying (including survival) among populations of an endemic isopod
Paramphisopus palustris
(Amphisopidae).
The survival of individuals from four isopod populations (two each from seasonal and semi‐perennial wetlands) were tested in a drying experiment with three treatments: control (permanently inundated), saturated sediment (water level maintained equal with the sediment surface), and dry (microcosms gradually raised out of the water causing sediments to dry out). Microrefuge use (three levels: no response, sought shelter or sought shelter/burrowed) was also compared among populations.
As expected, isopod mortality was highest in the dry treatment for all populations. Unexpectedly, isopods from the two semi‐perennial wetlands showed higher survival in response to drying than those from seasonal wetlands. All isopods showed dormancy in response to the dry treatment and curled their bodies to limit water loss from their ventral gills. Microrefuge use differed among populations but not between the two hydroregimes. However, there was some similarity in population responses according to genetic clade.
Isopods displayed some resistance to drying through dormancy behaviour and seeking microrefuges, which will increase population persistence under a drying climate. However, the reduced survival of individuals from seasonal wetland populations suggests that surviving in these wetlands is more challenging than in semi‐perennial or perennial regimes. These challenges are likely to be exacerbated as climate change further decreases hydroperiods and limits the availability of damp microrefuges. Consequently, longer‐term population persistence may be challenged as more wetlands become seasonal.
The responses of endemic species are not always correctly predicted from knowledge of more widespread and commonly studied species and our results suggest that there may be variation among populations. Although
P. palustris
showed some innate responses to drying, their long‐term persistence (and that of other endemic species) may be threatened as environmental conditions become more extreme.
In this article we explore the relationships amongst anti-doping sciences, 'abjection,' and the protection of 'women's' sport. We introduce three novel concepts: 'abjection bias,' 'abjection ...potential,' and 'intersectional abjection,' as tools with the potential to provide greater nuance to understanding the context for these contentious issues in contemporary sport. The debate concerning participation in women's sport-especially elite sport-of people who do not fit within traditional definition of 'women' is increasingly fraught with acrimony with anti-doping sciences often recruited as arbitrator. With access to opportunities such as participation at the Olympic Games at stake, emotions run high in arguments that typically centre on inclusion of transgender and gender diverse (TGD) athletes on the one hand and protection of the women's category on the other. While sport theorists have begun the important work of identifying the roots of these problems deep within the structure of modern sport and society itself, they have hitherto paid little attention to the philosophical underpinnings of that structure. Through the lens of feminist critical analysis, we seek, in this paper, to understand the complex role of 'abjection' in framing the current debate in sport and in related anti-doping sciences. From a clear definition of abjection as a perceived existential threat due to violation of the status quo, we introduce the new concepts of 'abjection bias,' 'abjection potential,' and 'intersectional abjection' in order to understand and explain what in common parlance we might call 'gut reaction.' By looking at the few notable previous treatments of sport abjection and highlighting the historical connections between anti-doping sciences and efforts to protect the women's category, we demonstrate that this co-development is, in part, more easily understood in the context of 'abjection.' We conclude that the clarity gained can also help to shed light on current policy decision-making in relation to the question of protecting the women's sport category.
The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >1020 eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within ∼50 Mpc through interactions ...with the cosmic microwave background. As there are no sufficiently powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or γ-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing.
Five cases of STEC O157 phage type (PT) 21/28 reported consumption of raw cows' drinking milk (RDM) produced at a dairy farm in the South West of England. STEC O157 PT21/28 was isolated from faecal ...specimens from milking cows on the implicated farm. Whole genome sequencing (WGS) showed that human and cattle isolates were the same strain. Further analysis of WGS data confirmed that sequences of isolates from an additional four cases (who did not report consumption of RDM when first questioned) fell within the same five single nucleotide polymorphism cluster as the initial five cases epidemiologically linked to the consumption of RDM. These four additional cases identified by WGS were investigated further and were, ultimately, associated with the implicated farm. The RDM outbreak strain encoded stx2a, which is associated with increased pathogenicity and severity of symptoms. Further epidemiological analysis showed that 70% of isolates within a wider cluster containing the outbreak strain were from cases residing in, or linked to, the same geographical region of England. During this RDM outbreak, use of WGS improved case ascertainment and provided insights into the evolution of a highly pathogenic clade of STEC O157 PT21/28 stx2a associated with the South West of England.
The LOFAR radio environment Offringa, A. R.; de Bruyn, A. G.; Zaroubi, S. ...
Astronomy & astrophysics,
01/2013, Letnik:
549
Journal Article
Recenzirano
Odprti dostop
Aims. This paper discusses the spectral occupancy for performing radio astronomy with the Low-Frequency Array (LOFAR), with a focus on imaging observations. Methods. We have analysed the ...radio-frequency interference (RFI) situation in two 24-h surveys with Dutch LOFAR stations, covering 30−78 MHz with low-band antennas and 115–163 MHz with high-band antennas. This is a subset of the full frequency range of LOFAR. The surveys have been observed with a 0.76 kHz/1 s resolution. Results. We measured the RFI occupancy in the low and high frequency sets to be 1.8% and 3.2% respectively. These values are found to be representative values for the LOFAR radio environment. Between day and night, there is no significant difference in the radio environment. We find that lowering the current observational time and frequency resolutions of LOFAR results in a slight loss of flagging accuracy. At LOFAR’s nominal resolution of 0.76 kHz and 1 s, the false-positives rate is about 0.5%. This rate increases approximately linearly when decreasing the data frequency resolution. Conclusions. Currently, by using an automated RFI detection strategy, the LOFAR radio environment poses no perceivable problems for sensitive observing. It remains to be seen if this is still true for very deep observations that integrate over tens of nights, but the situation looks promising. Reasons for the low impact of RFI are the high spectral and time resolution of LOFAR; accurate detection methods; strong filters and high receiver linearity; and the proximity of the antennas to the ground. We discuss some strategies that can be used once low-level RFI starts to become apparent. It is important that the frequency range of LOFAR remains free of broadband interference, such as DAB stations and windmills.
Anxiety and depression are highly prevalent in patients with COPD and their informal carers, and associated with numerous risk factors. However, few studies have investigated these in primary care or ...the link between patient and carer anxiety and depression. We aimed to determine this association and factors associated with anxiety and depression in patients, carers, and both (dyads), in a population-based sample.
This was a prospective, cross-sectional study of 119 advanced COPD patients and their carers. Patient and carer scores ≥8 on the Hospital Anxiety and Depression Scale defined symptoms of anxiety and depression,
tests determined associations between patient and carer symptoms of anxiety/depression, and
and independent
-tests for normally distributed variables (otherwise Mann-Whitney
tests) were used to identify other variables significantly associated with these symptoms in the patient or carer. Patient-carer dyads were categorized into four groups relating to the presence of anxious/depressive symptoms in: both patient and carer, patient only, carer only, and neither. Factors associated with dyad symptoms of anxiety/depression were determined with
tests and one-way analysis of variance for normally distributed variables (otherwise Kruskal-Wallis tests).
Prevalence of symptoms of anxiety and depression was 46.4% (n=52) and 42.9% (n=48) in patients, and 46% (n=52) and 23% (n=26) in carers, respectively. Patient and carer symptoms of anxiety/depression were significantly associated. Anxious and depressive symptoms in the patient were also significantly associated with more physical comorbidities, more exacerbations, greater dyspnea, greater fatigue, poor mastery, and depressive symptoms with younger age. Symptoms of carer anxiety were significantly associated with being female and separated/divorced/widowed, and depressive symptoms with younger age, higher educational level, and more physical comorbidities, and symptoms of carer anxiety and depression with more unmet support needs, greater subjective caring burden, and poor patient mastery. Dyad symptoms of anxiety/depression were significantly associated with greater patient fatigue.
Symptoms of anxiety and depression in COPD patients and carers are significantly associated. Given their high prevalence, considerable impact on mortality, impact on quality of life and health care use, and associations with each other, screening for and addressing patient and carer anxiety and depression in advanced COPD is recommended.
Abstract Objective. This study aimed to (1) assess the day-to-day variability of children's weekday physical activity for the whole-day, and when segmented into discrete periods of the day; and (2) ...compare boys' and girls' physical activity variability. Method. Fifty-eight children (aged 7–11 years; 31 boys) from a northwest England city wore accelerometers for 4 consecutive weekdays during November and December 2005. Intra-class correlations (ICCs) were calculated for 1 and 4 monitored days and segments of days to determine reliable estimates of moderate-to-vigorous physical activity (MVPA). The Spearman–Brown prophecy formula established the number of monitoring days required for 80% reliability. Results. Higher ICC coefficients were typically observed among boys. Eight days of boys' whole-day monitoring were needed to achieve a reliability of 0.8, while 10 days were required for girls. The pre-school segment was the most stable (boys' ICC = 0.862; girls' ICC = 0.770). Compared to girls, fewer days of boys' monitoring would be required during all segments other than the school day. Conclusion. Day-to-day physical activity variability was sex-specific, with boys' MVPA generally more stable than girls'. The greatest reliability occurred between 7 am and 3 pm, suggesting that physical activity behaviors are more consistent in the school environment.
Proteins provide essential functional regulation of many bioprocesses across all scales of life; however, new techniques to specifically modulate protein activity within living systems and in ...engineered biomaterials are needed to better interrogate fundamental cell signalling and guide advanced decisions of biological fate. Here we establish a generalizable strategy to rapidly and irreversibly activate protein function with full spatiotemporal control. Through the development of a genetically encoded and light-activated SpyLigation (LASL), bioactive proteins can be stably reassembled from non-functional split fragment pairs following brief exposure (typically minutes) to cytocompatible light. Employing readily accessible photolithographic processing techniques to specify when, where and how much photoligation occurs, we demonstrate precise protein activation of UnaG, NanoLuc and Cre recombinase using LASL in solution, biomaterials and living mammalian cells, as well as optical control over protein subcellular localization. Looking forward, we expect that these photoclick-based optogenetic approaches will find tremendous utility in probing and directing complex cellular fates in both time and three-dimensional space.
As a means of integrating bottom-up and top-down theories of subjective well-being (SWB), a framework was proposed that, in part, posits that both objective life circumstances and global personality ...dimensions indirectly affect SWB through their effects on the interpretation of life circumstances. This proposition was tested both cross-sectionally and longitudinally among a sample of approximately 375 men and women. Personality was operationalized in terms of the dispositional trait negative affectivity (NA), and the life circumstance investigated was health. Strong support was obtained for the hypothesized indirect effects of NA and objective health on SWB. Implications of the integrative framework for the study of SWB are discussed.
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