Abstract The transcription of genes that support memory processes are likely to be impacted by the normal aging process. Because Arc is necessary for memory consolidation and enduring synaptic ...plasticity, we examined Arc transcription within the aged hippocampus. Here, we report that Arc transcription is reduced within the aged hippocampus compared to the adult hippocampus during both “off line” periods of rest, and following spatial behavior. This reduction is observed within ensembles of CA1 “place cells”, which make less mRNA per cell, and in the dentate gyrus (DG) where fewer granule cells are activated by behavior. In addition, we present data suggesting that aberrant changes in methylation of the Arc gene may be responsible for age-related decreases in Arc transcription within CA1 and the DG. Given that Arc is necessary for normal memory function, these subregion-specific epigenetic and transcriptional changes may result in less efficient memory storage and retrieval during aging.
Pulsed-laser-induced quenching of ferromagnetic order has intrigued researchers since pioneering works in the 1990s. It was reported that demagnetization in gadolinium proceeds within 100 ps, but ...three orders of magnitude faster in ferromagnetic transition metals such as nickel. Here we show that a model based on electron-phonon-mediated spin-flip scattering explains both timescales on equal footing. Our interpretation is supported by ab initio estimates of the spin-flip scattering probability, and experimental fluence dependencies are shown to agree perfectly with predictions. A phase diagram is constructed in which two classes of laser-induced magnetization dynamics can be distinguished, where the ratio of the Curie temperature to the atomic magnetic moment turns out to have a crucial role. We conclude that the ultrafast magnetization dynamics can be well described disregarding highly excited electronic states, merely considering the thermalized electron system.
Air temperature (Tair) plays an important role in determining how a canopy intercepts snow and apart from event size is the single most important micrometeorological variable found to adequately ...influence interception rates and magnitude. We present results from a 6‐year study on snow‐forest interactions. This data set reveals the central role Tair plays in how a forest intercepts snow and the need to effectively incorporate this within snow process models. Warm temperature events show a higher canopy interception efficiency (CIE) for all sites across the study period, while colder Tair events demonstrated a lower corresponding CIE. Additionally, there is a structural component of the forest itself that plays a role in the ability of canopy to intercept snow. Recognizing the physical vertical structure of a forest as nontrivial, we present a simple canopy interception model that includes a novel three‐dimensional forest metric that captures canopy complexity, Gz, combined with event size and Tair to adequately predict event‐based interception. Low complexity forests decrease interception capacity from the outset, whereas a highly complex or diverse forest increases interception potential and leads to a nonlinear increase in temperature‐based canopy interception due to more surface area able to intercept falling snow. Essentially, forest structure sets the boundary condition of the potential to intercept, while event size and Tair determines the rate or amount of interception. We develop a simple canopy snow interception model from these data and compare modeled output against three commonly used interception models in both a maritime and continental snow climate. Partitioning the relative importance of snow‐forest interactions on canopy interception will help provide the information to accurately model snow‐forest interactions and also aid in our water resources predictive capabilities now and into the future.
Key Points
Snow interception in a maritime forest is driven by event size and air temperature within a boundary condition set by forest structure
We develop a simple canopy snow interception model from measured data across an elevation gradient and under various forest structure
Inclusion of air temperature in snow interception models is essential to adequately capture event‐based canopy interception variability
Early-life stress, such as maltreatment, institutionalization, and exposure to violence, is associated with accelerated telomere shortening. Telomere shortening may thus represent a biomarker of ...early adversity. Previous studies have suggested that responsive parenting may protect children from the negative biological and behavioral consequences of early adversity. This study examined the role of parental responsiveness in buffering children from telomere shortening following experiences of early-life stress. We found that high-risk children had significantly shorter telomeres than low-risk children, controlling for household income, birth weight, gender, and minority status. Further, parental responsiveness moderated the association between risk and telomere length, with more responsive parenting associated with longer telomeres only among high-risk children. These findings suggest that responsive parenting may have protective benefits on telomere shortening for young children exposed to early-life stress. Therefore, this study has important implications for early parenting interventions.
•Investigated the electroplasticity of an Al alloy under a pulsed electric current.•The same electric energy densities induced identical mechanical responses.•The formability of the Al alloy was ...significantly improved.•An expression for the contour of electroplastic stress–strain curve was suggested.
The electroplasticity of an aluminum 5052-H32 alloy under a pulsed electric current is investigated experimentally. A pulsed electric current is applied to a specimen simultaneously with a quasi-static uniaxial tensile load. The experimental result shows a ratchet shape stress–strain curve under a pulsed electric current. The formability of the selected aluminum alloy is significantly improved at near room temperature depending on the electric pulse parameters. An empirical expression to describe the upper boundary of the ratchet shape stress–strain curve of the aluminum alloy under a pulsed electric current is suggested. Two electroplastic coefficients are used in the suggested empirical expression: one is a material constant and the other accounts for the effects of the electric energy density and the electric pulse period. The result of the present study is expected to provide a basis to develop sheet metal forming processes using electroplasticity.
Cognitive apprenticeship theory emphasizes the process of making expert thinking “visible” to students and fostering the cognitive and meta-cognitive processes required for expertise. The purpose of ...this review was to evaluate the use of cognitive apprenticeship theory with the primary aim of understanding how and to what extent the theory has been applied to the design, implementation, and analysis of education in the health sciences. The initial search yielded 149 articles, with 45 excluded because they contained the term “cognitive apprenticeship” only in reference list. The remaining 104 articles were categorized using a theory talk coding scheme. An in depth qualitative synthesis and review was conducted for the 26 articles falling into the
major theory talk
category. Application of cognitive apprenticeship theory tended to focus on the methods dimension (e.g., coaching, mentoring, scaffolding), with some consideration for the content and sociology dimensions. Cognitive apprenticeship was applied in various disciplines (e.g., nursing, medicine, veterinary) and educational settings (e.g., clinical, simulations, online). Health sciences education researchers often used cognitive apprenticeship to inform instructional design and instrument development. Major recommendations from the literature included consideration for contextual influences, providing faculty development, and expanding application of the theory to improve instructional design and student outcomes. This body of research provides critical insight into cognitive apprenticeship theory and extends our understanding of how to develop expert thinking in health sciences students. New research directions should apply the theory into additional aspects of health sciences educational research, such as classroom learning and interprofessional education.
Simple Summary
Neoadjuvant chemotherapy is commonly used in several solid tumor malignancies, but remains understudied in the setting of locally advanced colon cancer. Advantages of this strategy ...extrapolated from other disease sites include early treatment of micro-metastatic disease, the ability to decrease local disease burden potentially leading to more effective resections and improved treatment tolerability. Approaches for accurate staging and safe administration of systemic treatment are being investigated in large, randomized clinical trials, but available data are either not mature enough or have not demonstrated a convincing argument for adoption into standard practice warranting further investigation.
Abstract
Early stage colon cancer is typically managed with surgical resection, although not all patients experience a durable remission. Adjuvant chemotherapy with a fluoropyrimidine, with or without oxaliplatin, is commonly utilized to increase the chance of cure, but its efficacy in the neoadjuvant setting is not well established. Preoperative chemotherapy has demonstrated safety and efficacy in other gastrointestinal malignancies, but there is a paucity of data from large, prospective randomized trials, although multiple are ongoing. In this review, we will discuss the theoretical risks and benefits, logistical difficulties, and available safety and efficacy data pertaining to the use of chemotherapy in locally advanced colon cancer.
ABSTRACT
We present the results of photometric and spectroscopic monitoring campaigns of the changing look AGN NGC 3516 carried out in 2018 to 2020 covering the wavelength range from the X-ray to the ...optical. The facilities included the telescopes of the CMO SAI MSU, the 2.3-m WIRO telescope, and the XRT and UVOT of Swift. We found that NGC 3516 brightened to a high state and could be classified as Sy1.5 during the late spring of 2020. We have measured time delays in the responses of the Balmer and He ii λ4686 lines to continuum variations. In the case of the best-characterized broad H β line, the delay to continuum variability is about 17 d in the blue wing and is clearly shorter, 9 d, in the red, which is suggestive of inflow. As the broad lines strengthened, the blue side came to dominate the Balmer lines, resulting in very asymmetric profiles with blueshifted peaks during this high state. During the outburst the X-ray flux reached its maximum on 2020 April 1 and it was the highest value ever observed for NGC 3516 by the Swift observatory. The X-ray hard photon index became softer, ∼1.8 in the maximum on 2020 April 21 compared to the mean ∼0.7 during earlier epochs before 2020. We have found that the UV and optical variations correlated well (with a small time delay of 1–2 d) with the X-ray until the beginning of 2020 April, but later, until the end of 2020 June, these variations were not correlated. We suggest that this fact may be a consequence of partial obscuration by Compton-thick clouds crossing the line of sight.
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