Forgetting Of Visual Discriminations By Pigeons

A series of three experiments examined the forgetting of visual discriminations in pigeons. The problems consisted of feature discriminations, with dot displays as the discriminative stimuli, and involved a successive go/no-go pecking-response. It was found in all three experiments that pigeons that had been trained to refrain from pecking an S- display, resumed pecking at these displays after retention intervals. It was argued that these data represent the first unequivocal demonstration of forgetting of discriminations in pigeons.;In addition to the simple demonstration of forgetting, it was found in Experiment 1 that the amount of forgetting progressively increased, in a negatively accelerated fashion, over intervals of 1, 10 and 20 days. Also, it was found that more forgetting occurred for a reverse discrimination than for a single discrimination. In Experiment 2 it was found that acquisition was retarded and more forgetting occurred for discriminations which involved highly similar stimuli. It was argued that these data represent the first reported instance of intraproblem similarity effects on retention in animals. In Experiment 3 the role of contextual cues on forgetting was examined. It was found that a change in contextual cues between acquisition and retention testing enhanced forgetting, when the contextual cues present during original acquisition were conspicuous; when these cues were relatively inconspicuous, a change in context had no effect on forgetting.;A retrieval failure model of memory processing was described and applied to the data from each of the three experiments. It was argued that forgetting of discriminations involves selective retrieval failure of specific target memories, as a result of changes in the retrievability of these memories over time. An explicit conceptual mechanism was postulated as a source of these changes in retrievability

A bacteriophage tubulin harnesses dynamic instability to center DNA in infected cells.

Dynamic instability, polarity, and spatiotemporal organization are hallmarks of the microtubule cytoskeleton that allow formation of complex structures such as the eukaryotic spindle. No similar structure has been identified in prokaryotes. The bacteriophage-encoded tubulin PhuZ is required to position DNA at mid-cell, without which infectivity is compromised. Here, we show that PhuZ filaments, like microtubules, stochastically switch from growing in a distinctly polar manner to catastrophic depolymerization (dynamic instability) both in vitro and in vivo. One end of each PhuZ filament is stably anchored near the cell pole to form a spindle-like array that orients the growing ends toward the phage nucleoid so as to position it near mid-cell. Our results demonstrate how a bacteriophage can harness the properties of a tubulin-like cytoskeleton for efficient propagation. This represents the first identification of a prokaryotic tubulin with the dynamic instability of microtubules and the ability to form a simplified bipolar spindle

Overload Injury of the Knees With Resistance-Exercise Overtraining: A Case Study

This is the publisher's version, also found at http://ehis.ebscohost.com/ehost/detail?vid=3&sid=cc60431c-6281-4940-bc2d-85f4c9ff2060%40sessionmgr11&hid=17&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=s3h&AN=SPHS-67196

THE IMPACT OF COVID-19 ON INFORMAL CAREGIVERS IN THE US

Background: Caregiver burden has negative effects on mental and physical health along with quality of life. Meanwhile, social and physical distancing protocols during the COVID-19 pandemic have created additional impacts on informal caregiving in a rapidly changing environment. Early research over the past year suggests that the pandemic has caused increased caregiver burden as well as caregiving intensity among these individuals. Purpose: Our primary purpose in this informational literature review is to describe the impacts of the pandemic on informal caregiver burden and the sudden shift in roles and responsibilities as a result of pandemic-related changes in caregiving. This review will describe emerging effects on various aspects of health among informal caregivers and explore the growing need to support unpaid caregiving during this time. Methods: A streamlined search was conducted to fit the scope of this review, with key terms determined to identify relevant publications. Common research databases and up-to-date mainstream resources were utilized. Notably, we focused on research published or released since March 2020, primarily rapidly reviewed studies, to align with the timing of the COVID-19 pandemic in the US. Results: Early research suggests that the pandemic has worsened caregiver burden and increased caregiving intensity and hours of care among unpaid, informal family caregivers. Reported health impacts include higher stress, pain, and depression, along with decreased social connectedness and quality of life. Notably, however, COVID-related research generally does not focus on the positive aspects of caregiving, such as its role as a source of purpose in life, creating an opportunity to explore ways to boost certain valuable personal resources among caregivers. Conclusions: Informal family caregivers face their own negative health outcomes and distress as a result of greater caregiver burden, intensity, and the changing landscape of caregiving during the ongoing COVID-19 pandemic. Immediate policy and support recommendations should be considered to alleviate informal caregiver burden and provide ongoing resources over the longer term. In addition, future work should explore the potential of boosting positive resources such as resilience and purpose to ease caregiver burden

Concentrating solar thermoelectric generators with a peak efficiency of 7.4%

Concentrating solar power normally employs mechanical heat engines and is thus only used in large-scale power plants; however, it is compatible with inexpensive thermal storage, enabling electricity dispatchability. Concentrating solar thermoelectric generators (STEGs) have the advantage of replacing the mechanical power block with a solid-state heat engine based on the Seebeck effect, simplifying the system. The highest reported efficiency of STEGs so far is 5.2%. Here, we report experimental measurements of STEGs with a peak efficiency of 9.6% at an optically concentrated normal solar irradiance of 211 kW m⁻², and a system efficiency of 7.4% after considering optical concentration losses. The performance improvement is achieved by the use of segmented thermoelectric legs, a high-temperature spectrally selective solar absorber enabling stable vacuum operation with absorber temperatures up to 600 °C, and combining optical and thermal concentration. Our work suggests that concentrating STEGs have the potential to become a promising alternative solar energy technology.United States. Department of Energy (DE-EE0005806)Solid-State Solar-Thermal Energy Conversion Center (DE-SC0001299)Solid-State Solar-Thermal Energy Conversion Center (DE-FG02-09ER46577

Charging-free electrochemical system for harvesting low-grade thermal energy

Efficient and low-cost systems are needed to harvest the tremendous amount of energy stored in low-grade heat sources (<100 °C). Thermally regenerative electrochemical cycle (TREC) is an attractive approach which uses the temperature dependence of electrochemical cell voltage to construct a thermodynamic cycle for direct heat-to-electricity conversion. By varying temperature, an electrochemical cell is charged at a lower voltage than discharge, converting thermal energy to electricity. Most TREC systems still require external electricity for charging, which complicates system designs and limits their applications. Here, we demonstrate a charging-free TREC consisting of an inexpensive soluble Fe(CN)[3−/4− over 6] redox pair and solid Prussian blue particles as active materials for the two electrodes. In this system, the spontaneous directions of the full-cell reaction are opposite at low and high temperatures. Therefore, the two electrochemical processes at both low and high temperatures in a cycle are discharge. Heat-to-electricity conversion efficiency of 2.0% can be reached for the TREC operating between 20 and 60 °C. This charging-free TREC system may have potential application for harvesting low-grade heat from the environment, especially in remote areas.United States. Dept. of Energy. Office of Science (Solid-State Solar-Thermal Energy Conversion Center Award DE-SC0001299/DE-FG02-09ER46577)United States. Air Force Office of Scientific ResearchUnited States. Dept. of Energy (EERE Award DE-EE0005806

Diagnostic Utility of the Impact of Event Scale-Revised in Two Samples of Survivors of War

The study aimed at examining the diagnostic utility of the Impact of Event Scale-Revised (IES-R) as a screening tool for post-traumatic stress disorder (PTSD) in survivors of war. The IES-R was completed by two independent samples that had survived the war in the Balkans: a sample of randomly selected people who had stayed in the area of former conflict (n = 3,313) and a sample of refugees to Western European countries (n = 854). PTSD was diagnosed using the MINI International Neuropsychiatric Interview. Prevalence of PTSD was 20.1% in the Balkan sample and 33.1% in the refugee sample. Results revealed that when considering a minimum value of specificity of 0.80, the optimally sensitive cut-off score for screening for PTSD in the Balkan sample was 34. In both the Balkan sample and the refugee sample, this cut-off score provided good values on sensitivity (0.86 and 0.89, respectively) and overall efficiency (0.81 and 0.79, respectively). Further, the kappa coefficients for sensitivity for the cut-off of 34 were 0.80 in both samples. Findings of this study support the clinical utility of the IES-R as a screening tool for PTSD in large-scale research studies and intervention studies if structured diagnostic interviews are regarded as too labor-intensive and too costly

Lycoris -- a large-area, high resolution beam telescope

A high-resolution beam telescope is one of the most important and demanding infrastructure components at any test beam facility. Its main purpose is to provide reference particle tracks from the incoming test beam particles to the test beam users, which allows measurement of the performance of the device-under-test (DUT). \LYCORIS, a six-plane compact beam telescope with an active area of $\sim$10$\times$\SI{10}{\square\centi\metre} (extensible to 10$\times$\SI{20}{\square\centi\metre}) was installed at the \DIITBF in 2019, to provide a precise momentum measurement in a \SI{1}{\tesla} solenoid magnet or to provide tracking over a large area. The overall design of \LYCORIS will be described as well as the performance of the chosen silicon sensor. The \SI{25}{\micro\metre} pitch micro-strip sensor used for \LYCORIS was originally designed for the \SID detector concept for the International Linear Collider. It adopts a second metallization layer to route signals from strips to the bump-bonded \KPIX ASIC and uses a wire-bonded flex cable for the connection to the DAQ and the power supply system. This arrangement eliminates the need for a dedicated hybrid PCB. Its performance was tested for the first time in this project. The system has been evaluated at the \DIITBF in several test-beam campaigns and has demonstrated an average single-point resolution of \SI{7.07}{\micro\meter}.Comment: 43 pages, 37 figure