1,067 research outputs found

    Mechanisms of induced susceptibility to Diplodia tip blight in drought-stressed Austrian pine

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    Plants experiencing drought stress are frequently more susceptible to pathogens, likely via alterations in physiology that create favorable conditions for pathogens. Common plant responses to drought include the production of reactive oxygen species (ROS) and the accumulation of free amino acids (AAs), particularly proline. These same phenomena also frequently occur during patho-genic attack. Therefore, drought-induced perturbations in AA and ROS metabolism could potentially contribute to the observed enhanced susceptibility. Furthermore, nitrogen (N) availability can influence AA accumulation and affect plant resistance, but its contributions to drought-induced susceptibility are largely unexplored. Here we show that drought induces accumulation of hydrogen peroxide (H2O2) in Austrian pine (Pinus nigra Arnold) shoots, but that shoot infection by the blight and canker pathogen Diplodia sapinea (Fr.) Fuckel leads to large reductions in H2O2 levels in droughted plants. In in vitro assays, H2O2 was toxic to D. sapinea, and the fungus responded to this oxidative stress by increasing catalase and peroxidase activities, resulting in sub-stantial H2O2 degradation. Proline increased in response to drought and infection when examined independently, but unlike all other AAs, proline further increased in infected shoots of droughted trees. In the same tissues, the proline precursor, glutamate, decreased significantly. Proline was found to protect D. sapinea from H2O2 damage, while also serving as a preferred N source in vitro. Fertilization increased constitutive and drought-induced levels of some AAs, but did not affect plant resistance. A ne

    Hardness of Wood Baseball Bats

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    Finite Element Modeling of Wood Bat Profiles for Durability

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    AbstractThe bats used in Major League Baseball (MLB) are required to be turned from a single piece of wood. Northern white ash had been the wood of choice until the introduction of hard maple in the late 1990s. Since the introduction of maple to the game, there was a perceived increase in the rate of bats to exhibit multiple piece failures (MPF)—both ash and maple. These failures introduced a new aspect to the game that can be a significant factor during play, i.e. pieces of bats going into the field of play, thereby distracting fielders while reacting to the batted ball. Observations of bat breakage in the field and lab testing of bats in controlled conditions have shown the bat durability is a function of wood quality and bat profile. Wood quality is described by the density and the slope of grain of the wood used in the bat. The density and the slope of grain determine the effective strength of the wood. The bat profile is described by the variation in the diameter of the bat along its length. The wood densities and bat profiles which are preferred by players, are typically in direct contradiction with what makes for a durable bat. In this paper, the finite element method is used to develop calibrated models of the breaking of wood bats in controlled lab conditions. The modeling approach is then used to explore how bat profile influences bat durability and what potential changes can be made in bat profile to satisfy player desires while increasing bat durability

    Comparative organization of the claustrum: what does structure tell us about function?

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    The claustrum is a subcortical nucleus present in all placental mammals. Many anatomical studies have shown that its inputs are predominantly from the cerebral cortex and its outputs are back to the cortex. This connectivity thus suggests that the claustrum serves to amplify or facilitate information processing in the cerebral cortex. The size and the complexity of the cerebral cortex change dramatically over evolution. Rodents are lissencephalic, with few cortical areas, while many primates have a greatly expanded cortex and many cortical areas. This evolutionary diversity in the cerebral cortex raises several questions about the claustrum. Does its volume expand in coordination with the expansion of cortex and does it acquire new functions related to the new cortical functions? We have examined the organization of the claustrum in animals with large brains, including great apes and cetaceans. Our data suggest that the claustrum is not always a continuous structure. In monkeys and gorillas there are a few isolated islands of cells near the main body of the nucleus. In cetaceans, however, there are many isolated cell islands. These data suggest constraints on the possible function of the claustrum. Some authors propose that the claustrum has a more global role in perception or consciousness that requires intraclaustral integration of information. These theories postulate mechanisms like gap junctions between claustral cells or a syncytium to mediate intraclaustral processing. The presence of discontinuities in the structure of the claustrum, present but minimal in primates, but dramatically clear in cetaceans, argues against the proposed mechanisms of intraclaustral processing of information. The best interpretation of function, then, is that each functional subdivision of the claustrum simply contributes to the function of its cortical partner

    A Comparative Perspective on Minicolumns and Inhibitory GABAergic Interneurons in the Neocortex

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    Neocortical columns are functional and morphological units whose architecture may have been under selective evolutionary pressure in different mammalian lineages in response to encephalization and specializations of cognitive abilities. Inhibitory interneurons make a substantial contribution to the morphology and distribution of minicolumns within the cortex. In this context, we review differences in minicolumns and GABAergic interneurons among species and discuss possible implications for signaling among and within minicolumns. Furthermore, we discuss how abnormalities of both minicolumn disposition and inhibitory interneurons might be associated with neuropathological processes, such as Alzheimer's disease, autism, and schizophrenia. Specifically, we explore the possibility that phylogenetic variability in calcium-binding protein-expressing interneuron subtypes is directly related to differences in minicolumn morphology among species and might contribute to neuropathological susceptibility in humans

    Control of Heterobasidion in Norway Spruce Stands: The Impact of Stump Cover on Efficacy of Urea and Phlebiopsis gigantea and Implications for Forest Management

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    This study investigated the efficacy of Rotstop, a native Latvian Phlebiopsis gigantea strain and 35% urea solution in combination with a stump cover treatment to control against natural spore infection by Heterobasidion spp. upon precommercial thinning of Norway spruce in three stands growing on former agricultural lands. The major findings were that (i) infection rates of Heterobasidion spp. on stumps treated with the native P. gigantea strain, Rotstop or urea are similar when stumps are uncovered, and (ii) stump cover promotes stump colonization by the Latvian P. gigantea strain and Rotstop, leading to a significantly smaller relative area colonized by Heterobasidion spp., as well greater efficiency against Heterobasidion in comparison with urea. Covering of stumps appears beneficial for controlling Heterobasidion stump colonization and may be valuable to forest owners if used in small-scale operations, but it is impractical in automatized thinnings, where managers should consider using regular Rotstop without covering the stumps

    Differences in Rate of Perceived Exertion and Workload Intensity in Males and Females during Submaximal Arm and Leg Ergometry

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    International Journal of Exercise Science 15(4): 1222-1235, 2022. Purpose: Arm ergometry (AE) is necessitated for individuals unable to perform leg ergometry (LE) exercise. This study explored gender differences in RPE and workload (WL) during AE and LE at submaximal target heart rates (THR). Methods: 35 healthy college-aged individuals were randomly allocated to begin exercise on either AE or LE. Participants exercised on both modes with increasing WL to achieve submaximal THRs of 110, 120, 130, 140 and 150 beats per minute (bpm). Factorial ANOVAs tested for differences in RPE and WL. Results: No significant differences were found in RPE between genders, as well as between arm and leg exercise (p \u3e 0.001). For WL, a significant main effect was found for mode with LE greater than AE (p \u3c 0.001), and gender, with males greater than females (p \u3c 0.001). A significant interaction effect was also found for HR and mode, with a greater increase in WL during LE compared to AE in both genders (p = 0.001). Conclusions: Exercise specialists typically prescribe exercise based on a chosen THR. The results of this study provide meaningful data on mean RPE and WL responses that a given THR elicits for ergometry. The finding of no differences in RPE between AE and LE informs the clinician that at any given submaximal THR, similar RPE scores can be expected during AE and LE. Further research is warranted to investigate differences in wider populations

    Development of Constructed Wetlands for the Reuse of Wastewat r in Semi-Arid Regions

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    Hill Air Force Base (AFB), UT, is responsible for the operation and maintenance of the Utah Test and Training Range (UTTR). The range contains waste-water treatment and disposal facilities that consist of two infiltration ponds operated in parallel, followed by an emergency overflow basin that safeguards against unexpectedly high flow rates. A previous evaluation concluded that the existing facilities should be replaced, at a relatively high cost and with no possibility for beneficial water reuse. The U.S. Army Construction Engineering Research Laboratories (USACERL) was requested to further evaluate the system and to identify cost-effective, feasible alternatives. USACERL researchers identified a potential process train that included retention of the existing ponds, use of a constructed wetland for further treatment following the ponds, construction of a small basin following the wetland to improve wildlife habitat, and the possibility of pumping treated effluent back to the built-up portion of Hill AFB for reuse as landscape irrigation

    Neuroanatomy of the Killer Whale (Orcinus orca) From Magnetic Resonance Images

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    This article presents the first series of MRI-based anatomically labeled sectioned images of the brain of the killer whale (Orcinus orca). Magnetic resonance images of the brain of an adult killer whale were acquired in the coronal and axial planes. The gross morphology of the killer whale brain is comparable in some respects to that of other odontocete brains, including the unusual spatial arrangement of midbrain structures. There are also intriguing differences. Cerebral hemispheres appear extremely convoluted and, in contrast to smaller cetacean species, the killer whale brain possesses an exceptional degree of cortical elaboration in the insular cortex, temporal operculum, and the cortical limbic lobe. The functional and evolutionary implications of these features are discussed

    Effects of Exercise and Sertraline on Measures of Coronary Heart Disease Risk in Patients With Major Depression: Results From the SMILE-II Randomized Clinical Trial

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    To assess the effects of supervised and home-based aerobic exercise training, and antidepressant pharmacotherapy (sertraline) on coronary heart disease (CHD) risk factors in a sample of participants with major depressive disorder (MDD)
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