1,839 research outputs found
Stochastic optimization of a cold atom experiment using a genetic algorithm
We employ an evolutionary algorithm to automatically optimize different
stages of a cold atom experiment without human intervention. This approach
closes the loop between computer based experimental control systems and
automatic real time analysis and can be applied to a wide range of experimental
situations. The genetic algorithm quickly and reliably converges to the most
performing parameter set independent of the starting population. Especially in
many-dimensional or connected parameter spaces the automatic optimization
outperforms a manual search.Comment: 4 pages, 3 figure
The Actinomyosin Motor Drives Malaria Parasite Red Blood Cell Invasion but Not Egress.
Apicomplexa are obligate intracellular parasites that actively invade, replicate within, and egress from host cells. The parasite actinomyosin-based molecular motor complex (often referred to as the glideosome) is considered an important mediator of parasite motility and virulence. Mature intracellular parasites often become motile just prior to egress from their host cells, and in some genera, this motility is important for successful egress as well as for subsequent invasion of new host cells. To determine whether actinomyosin-based motility is important in the red blood cell egress and invasion activities of the malaria parasite, we have used a conditional genetic approach to delete GAP45, a primary component of the glideosome, in asexual blood stages of Plasmodium falciparum Our results confirm the essential nature of GAP45 for invasion but show that P. falciparum does not require a functional motor complex to undergo egress from the red blood cell. Malarial egress therefore differs fundamentally from induced egress in the related apicomplexan Toxoplasma gondiiIMPORTANCE Clinical malaria results from cycles of replication of single-celled parasites of the genus Plasmodium in red blood cells. Intracellular parasite replication is followed by a highly regulated, protease-dependent process called egress, in which rupture of the bounding membranes allows explosive release of daughter merozoites which rapidly invade fresh red cells. A parasite actinomyosin-based molecular motor (the glideosome) has been proposed to provide the mechanical force to drive invasion. Studies of the related parasite Toxoplasma gondii have shown that induced egress requires parasite motility, mediated by a functional glideosome. However, whether the glideosome has a similar essential role in egress of malaria merozoites from red blood cells is unknown. Here, we show that although a functional glideosome is required for red blood cell invasion by Plasmodium falciparum merozoites, it is not required for egress. These findings place further emphasis on the key role of the protease cascade in malarial egress
A study of older adults’ mental health across 33 countries during the covid-19 pandemic
Despite older adults’ extremely high vulnerability to COVID-19 complications and death, few studies have examined how personal characteristics and the COVID-19 pandemic have impacted the mental health of older adults at the global level. The purpose of this study was to examine the relationships among demographics, COVID-19 life impacts, and depression and anxiety in adults aged 60 and older from 33 countries. A sample of 823 older adults aged 60–94 and residing in 33 countries completed a 10-minute online survey following recruitment from mailing lists and social media. Being separated from and having conflicts with loved ones predicted both anxiety and depression, as did residing in a country with higher income. Getting medical treatment for severe symptoms of COVID-19 and having decreased work responsibilities predicted depression, but adjustment to working from home and younger age predicted both depression and anxiety. Participants from Europe and Central Asia reported higher depression than those from all other regions and higher anxiety than those from Latin America and the Caribbean. The COVID-19 pandemic has had serious deleterious effects on the mental health of older adults worldwide. The current findings have direct implications for mental health services that may be delivered to older adults to help facilitate healthy psychological adjustment
Interaction of chromaffin granules with plasma membranes mediated by Ca2+ and Mg2+-ATP using self-generating gradients of percoll(R)
Grafenstein H von, Neumann E. Interaction of chromaffin granules with plasma membranes mediated by Ca2+ and Mg2+-ATP using self-generating gradients of percoll(R). FEBS Letters. 1981;123(2):238-240
The Role of Education for Intergenerational Income Mobility: A comparison of the United States, Great Britain, and Sweden
Previous studies have found that intergenerational income persistence is relatively high in the United States and Britain, especially as compared to Nordic countries. We compare the association between family income and sons’ earnings in the United States (National Longitudinal Study of Youth 1979), Britain (British Cohort Study 1970), and Sweden (Population Register Data, 1965 cohort), and find that both income elasticities and rank-order correlations are highest in the United States, followed by Britain, with Sweden being clearly more equal. We ask whether differences in educational inequality and in return to qualifications can explain these cross-country differences. Surprisingly, we find that this is not the case, even though returns to education are higher in the United States. Instead, the low income mobility in the United States and Britain is almost entirely due to the part of the parent-son association that is not mediated by educational attainment. In the United States and especially Britain, parental income is far more important for earnings at a given level of education than in Sweden, a result that holds also when controlling for cognitive ability. This goes against widespread ideas of the United States as a country where the role of ascription is limited and meritocratic stratification prevails
Quality of life of patients with epilepsy (Hungarian survey)
We assessed the quality of life (QOL) of patients with epilepsy using the Quality of Life in Epilepsy Inventory (QOLIE-31). As the first step we compared our results with the data from an American survey in order to validate the test in Hungary. The results show that the Hungarian values were lower but that they followed the same trends as the American data. There was only one controversial result in the question-group of the 'the effects of treatment', which could be explained by the differences in habits and conventions, opportunities and expectations between Hungarian and American epileptic patients. We found significant differences in many aspects of quality of life with respect to (a) gender (general quality of life, seizure worry), (b) pharmacological treatment form (cognitive functions, medication effects, total score and social and role functioning) and (c) economic activity of patients (cognitive functions, emotional well-being, energy/fatigue, medication effects, overall quality of life, overall scores, seizure worry, social and role functioning). We have tried to explain the differences found by taking either the characteristics of epilepsy or the social background of the epileptic patient into consideration. Based on previous knowledge we have tried to define the situations where the assessment of quality of life for people with epilepsy, may be beneficial to their core. (C) 2001 BEA Trading Ltd
Trauma-Related Distress During the COVID-19 Pandemic In 59 Countries
First published online March 11, 2022The COVID-19 pandemic has upended life like few other events in modern history, with differential impacts on varying population groups. This study examined trauma-related distress among 6,882 adults ages 18 to 94 years old in 59 countries during April to May 2020. More than two-thirds of participants reported clinically significant trauma-related distress. Increased distress was associated with unemployment; identifying as transgender, nonbinary, or a cisgender woman; being from a higher income country; current symptoms and positive diagnosis of COVID-19; death of a loved one; restrictive government-imposed isolation; financial difficulties; and food insecurity. Other factors associated with distress included working with potentially infected individuals, care needs at home, a difficult transition to working from home, conflict in the home, separation from loved ones, and event restrictions. Latin American and Caribbean participants reported more trauma-related distress than participants from Europe and Central Asia. Findings inform treatment efforts and highlight the need to address trauma-related distress to avoid long-term mental health consequences.The author(s) disclosed receipt of the following financial support for the research, authorship,
and/or publication of this article: This work was supported by the European Commission
(H2020-MSCA-IF-2018-837228-ENGRAVING). Daniela Ramos-Usuga was supported by
a predoctoral fellowship from the Basque Government (PRE_2019_1_0164)
Moderate, little, or no improvements in neurobehavioral symptoms among individuals with long COVID: A 34-country retrospective study
(1) Background: Some people with COVID-19 develop a series of symptoms that last for several months after infection, known as Long COVID. Although these symptoms interfere with people’s daily functioning and quality of life, few studies have focused on neurobehavioral symptoms and the risk factors associated with their development; (2) Methods: 1001 adults from 34 countries who had previously tested positive for COVID-19 completed the Neurobehavioral Symptom Inventory reporting the symptoms before their COVID-19 diagnosis, during the COVID-19 infection, and currently; (3) Results: Participants reported large-sized increases before vs. during COVID-19 in all domains. Participants reported a medium-sized improvement (during COVID-19 vs. now) in somatic symptoms, a small-sized improvement in affective symptoms, and very minor/no improvement in cognitive symptoms. The risk factors for increased neurobehavioral symptoms were: being female/trans, unemployed, younger age, low education, having another chronic health condition, greater COVID-19 severity, greater number of days since the COVID-19 diagnosis, not having received oxygen therapy, and having been hospitalized. Additionally, participants from North America, Europe, and Central Asia reported higher levels of symptoms across all domains relative to Latin America and Sub-Saharan Africa; (4) Conclusions: The results highlight the importance of evaluating and treating neurobehavioral symptoms after COVID-19, especially targeting the higher-risk groups identified. General rehabilitation strategies and evidence-based cognitive rehabilitation are needed in both the acute and Long COVID phases.Daniela Ramos Usuga was supported by a predoctoral fellowship from the Basque Government (PRE_2019_1_0164)
Modification and preservation of environmental signals in speleothems
Speleothems are primarily studied in order to generate archives of climatic change and results have led to significant advances in identifying and dating major shifts in the climate system. However, the climatological meaning of many speleothem records cannot be interpreted unequivocally; this is particularly so for more subtle shifts and shorter time periods, but the use of multiple proxies and improving understanding of formation mechanisms offers a clear way forward. An explicit description of speleothem records as time series draws attention to the nature and importance of the signal filtering processes by which the weather, the seasons and longer-term climatic and other environmental fluctuations become encoded in speleothems. We distinguish five sources of variation that influence speleothem geochemistry: atmospheric, vegetation/soil, karstic aquifer, primary speleothem crystal growth and secondary alteration and give specific examples of their influence. The direct role of climate diminishes progressively through these five factors. \ud
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We identify and review a number of processes identified in recent and current work that bear significantly on the conventional interpretation of speleothem records, for example: \ud
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1) speleothem geochemistry can vary seasonally and hence a research need is to establish the proportion of growth attributable to different seasons and whether this varies over time. \ud
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2) whereas there has traditionally been a focus on monthly mean �´18O data of atmospheric moisture, current work emphasizes the importance of understanding the synoptic processes that lead to characteristic isotope signals, since changing relative abundance of different weather types might 1Corresponding author, fax +44(0)1214145528, E-mail: [email protected] control their variation on the longer-term. \ud
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3) the ecosystem and soil zone overlying the cave fundamentally imprint the carbon and trace element signals and can show characteristic variations with time. \ud
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4) new modelling on aquifer plumbing allows quantification of the effects of aquifer mixing. \ud
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5) recent work has emphasized the importance and seasonal variability of CO2-degassing leading to calcite precipitation upflow of a depositional site on carbon isotope and trace element composition of speleothems. \ud
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6) Although much is known about the chemical partitioning between water and stalagmites, variability in relation to crystal growth mechanisms and kinetics is a research frontier. \ud
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7) Aragonite is susceptible to conversion to calcite with major loss of chemical information, but the controls on the rate of this process are obscure. \ud
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Analytical factors are critical to generate high-resolution speleothem records. A variety of methods of trace element analysis are available, but standardization is a common problem with the most rapid methods. New stable isotope data on Irish stalagmite CC3 compares rapid laser-ablation techniques with the conventional analysis of micromilled powders and ion microprobe methods. A high degree of comparability between techniques for �´18O is found on the mm-cm scale, but a previously described high-amplitude oxygen isotope excursion around 8.3 ka is identified as an analytical artefact related to fractionation of the laser-analysis associated with sample cracking. High-frequency variability of not less than 0.5o/oo may be an inherent feature of speleothem �´18O records
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