830 research outputs found

    Germination and storage of apple seeds

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    Apple seeds will not germinate immediately after the fruit has become mature enough for picking. It is necessary for the seed to pass thru a stage of after-ripening. The freshly extracted apple seed contains about 85 percent moisture. At room temperature approximately one-half of the moisture is lost during the first five days. Soaking the seed prior to planting does not increase germination. Ninety-one percent of apple seeds prevented from drying out when they were extracted from the fruit germinated. The best temperature for storage was found to be a temperature between 10 and 30 C. Seeds which had air dried germinated poorly in all cases. Apple seeds which had been air dried and kept for a year did not germinate. Apple seeds may be planted any time after Nov. 1. Where seeds are to be shipped long distances, special precaution must be made to keep the seeds from deteriorating. The seed coat is not a factor in causing delayed germination

    A baseline assessment of migratory and resident bird use of a prairie restoration site in eastern Washington

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    Prairies, and other types of grassland ecosystems, have suffered some of the most profound losses worldwide, due to anthropogenic factors such as fossil fuel extraction, agriculture, and climate change. Likewise, organisms inhabiting grassland ecosystems have become extirpated across much of their historical range, not the least of which has been a 50% decline in grassland birds since the 1960s. In response to losses of intact prairie in eastern Washington, a 120-ac site has been established on the EWU campus to regenerate native prairie and monitor changes in the ecosystem as native plants recolonize and replace non-natives. Because birds are an important indicator species of ecosystem health, the goal of our research was to estimate baseline abundance and diversity of birds at the prairie restoration site before restoration takes place. We also assessed bird abundance and diversity at a small, intact prairie remnant 20 mi north of the EWU campus to compare current bird use of the restoration site with that of an intact prairie system. We assessed bird abundance and bird diversity using the line-transect method. We established one transect at each site, and counted all birds seen or heard within 50 meters of the transects. Our findings will provide a baseline of knowledge about how and when birds will begin to reinhabit the EWU restoration site and inform future restoration efforts on the benefits and outcomes of restoring native grasslands locally, and worldwide

    Chondroitin Sulfate Proteoglycans Are a Common Component of Neuronal Inclusions and Astrocytic Reaction in Neurodegenerative Diseases

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    Previously, we showed three differentially sulfated forms of chondroitin sulfate proteoglycans (CSPG) associated with senile plaques, astrocytes and neurofibrillary tangles in Alzheimer\u27s disease. Here, monoclonal antibodies were used to demonstrate CSPGs in other neurodegenerative diseases. CSPGs were found associated with inclusions of Parkinson\u27s, diffuse Lewy body, Pick\u27s diseases, and progressive supranuclear palsy. Reacting astrocytes in each of these neurodegenrative diseases and Huntington\u27s disease showed immunoreactivity for CSPG. CSPG distribution in a variety of neurodegenerative diseases suggests that similar mechanisms may be involved in the accumulation of proteoglycans in a number of filamentous inclusions

    Manipulation of drugs to achieve the required dose is intrinsic to paediatric practice but is not supported by guidelines or evidence

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    Background: A lack of age-appropriate formulations can make it difficult to administer medicines to children. A manipulation of the dosage form may be required to achieve the required dose. This study aimed to describe medicines that are manipulated to achieve the required dose in paediatric practice.Method: A structured, undisguised observational study and postal survey. The observational study investigated drug manipulations occurring in clinical practice across three sites. The questionnaire, administered to a sample of paediatric nurses throughout the UK, surveyed manipulations conducted and nurses' experiences and views.Results: The observational study identified 310 manipulations, of which 62% involved tablets, 21% were intravenous drugs and 10% were sachets. Of the 54 observed manipulations 40 involved tablets with 65% of the tablets being cut and 30% dispersed to obtain a smaller dose. 188 manipulations were reported by questionnaire respondents, of these 46% involved tablets, 12% were intravenous drugs, and 12% were nebuliser solutions. Manipulations were predominantly, but not exclusively, identified in specialist clinical areas with more highly dependent patients. Questionnaire respondents were concerned about the accuracy of the dose achieved following manipulations and the lack of practice guidance.Conclusion: Manipulations to achieve the required dose occur throughout paediatric in-patient settings. The impact of manipulations on the efficacy of the drugs, the accuracy of the dose and any adverse effects on patients is not known. There is a need to develop evidence-based guidance for manipulations of medicines in children

    R-matrix Quantization of the Elliptic Ruijsenaars--Schneider model

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    It is shown that the classical L-operator algebra of the elliptic Ruijsenaars-Schneider model can be realized as a subalgebra of the algebra of functions on the cotangent bundle over the centrally extended current group in two dimensions. It is governed by two dynamical r and rˉ\bar{r}-matrices satisfying a closed system of equations. The corresponding quantum R and R\overline{R}-matrices are found as solutions to quantum analogs of these equations. We present the quantum L-operator algebra and show that the system of equations on R and R\overline{R} arises as the compatibility condition for this algebra. It turns out that the R-matrix is twist-equivalent to the Felder elliptic R^F-matrix with R\overline{R} playing the role of the twist. The simplest representation of the quantum L-operator algebra corresponding to the elliptic Ruijsenaars-Schneider model is obtained. The connection of the quantum L-operator algebra to the fundamental relation RLL=LLR with Belavin's elliptic R matrix is established. As a byproduct of our construction, we find a new N-parameter elliptic solution to the classical Yang-Baxter equation.Comment: latex, 29 pages, some misprints are corrected and the meromorphic version of the quantum L-operator algebra is discusse

    Mapping social reward and punishment processing in the human brain:A voxel-based meta-analysis of neuroimaging findings using the social incentive delay task

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    Social rewards or punishments motivate human learning and behaviour, and alterations in the brain circuits involved in the processing of these stimuli have been linked with several neuropsychiatric disorders. However, questions still remain about the exact neural substrates implicated in social reward and punishment processing. Here, we conducted four Anisotropic Effect Size Signed Differential Mapping voxel-based meta-analyses of fMRI studies investigating the neural correlates of the anticipation and receipt of social rewards and punishments using the Social Incentive Delay task. We found that the anticipation of both social rewards and social punishment avoidance recruits a wide network of areas including the basal ganglia, the midbrain, the dorsal anterior cingulate cortex, the supplementary motor area, the anterior insula, the occipital gyrus and other frontal, temporal, parietal and cerebellar regions not captured in previous coordinate-based meta-analysis. We identified decreases in the BOLD signal during the anticipation of both social reward and punishment avoidance in regions of the default-mode network that were missed in individual studies likely due to a lack of power. Receipt of social rewards engaged a robust network of brain regions including the ventromedial frontal and orbitofrontal cortices, the anterior cingulate cortex, the amygdala, the hippocampus, the occipital cortex and the brainstem, but not the basal ganglia. Receipt of social punishments increased the BOLD signal in the orbitofrontal cortex, superior and inferior frontal gyri, lateral occipital cortex and the insula. In contrast to the receipt of social rewards, we also observed a decrease in the BOLD signal in the basal ganglia in response to the receipt of social punishments. Our results provide a better understanding of the brain circuitry involved in the processing of social rewards and punishment. Furthermore, they can inform hypotheses regarding brain areas where disruption in activity may be associated with dysfunctional social incentive processing during diseas

    Classes of fast and specific search mechanisms for proteins on DNA

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    Problems of search and recognition appear over different scales in biological systems. In this review we focus on the challenges posed by interactions between proteins, in particular transcription factors, and DNA and possible mechanisms which allow for a fast and selective target location. Initially we argue that DNA-binding proteins can be classified, broadly, into three distinct classes which we illustrate using experimental data. Each class calls for a different search process and we discuss the possible application of different search mechanisms proposed over the years to each class. The main thrust of this review is a new mechanism which is based on barrier discrimination. We introduce the model and analyze in detail its consequences. It is shown that this mechanism applies to all classes of transcription factors and can lead to a fast and specific search. Moreover, it is shown that the mechanism has interesting transient features which allow for stability at the target despite rapid binding and unbinding of the transcription factor from the target.Comment: 65 pages, 23 figure

    Effect of Acute Heat Exposure on the Pressor Response to a Voluntary Hypoxic Apnea: A Cross-tolerance Study

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    The pressor response induced by a voluntary hypoxic apnea is exaggerated in individuals with obstructive sleep apnea and is strongly correlated to sympathetic overactivity. Acute heat exposure alters neural control of blood pressure, but its effect on the pressor response to a voluntary hypoxic apnea has never been explored. PURPOSE: To test the hypothesis that acute heat exposure attenuates the pressor response to a voluntary hypoxic apnea, and thereby manifest as a form of physiological cross-tolerance. METHODS: Eight adults (3 females, 26 ± 2 yrs) were exposed to passive heat stress (water perfused suit) sufficient to increase body core temperature by 1.2 °C. Voluntary hypoxic apneas were performed in duplicate before acute heat exposure (pre-heat) and in recovery when body core temperature returned to ≤ 0.3 °C of baseline. Participants breathed gas mixtures of varying FiO2 (21%, 16%, and 12%; randomized) for 1 min followed immediately by a 15 s end-expiratory apnea. Beat-by-beat arterial blood pressure (Finometer) and arterial oxygen saturation (finger pulse oximetry) were measured throughout. The pressor response was calculated as the difference between baseline mean arterial pressure and the peak response following each apnea. RESULTS: The change in arterial oxygen saturation during each apnea did not differ from pre-heat to recovery (FiO2 21%, pre-heat 0 ± 1 % vs. recovery 0 ± 2 %; FiO2 16%, pre-heat -4 ± 1 % vs. recovery -4 ± 2 %; FiO2 12%, pre-heat -8 ± 3 % vs. recovery -10 ± 4 %; P = 0.3 for interaction). The pressor response to a voluntary apnea was attenuated in recovery from acute heat exposure across all concentrations of FiO2 (FiO2 21%, pre-heat 19 ± 8 mmHg vs. recovery 16 ± 8 mmHg; FiO2 16%, pre-heat 27 ± 8 mmHg vs. recovery 20 ± 8 mmHg; FiO2 12%, pre-heat 33 ± 11 mmHg vs. recovery 27 ± 13 mmHg; P = 0.02 for main effect of time). CONCLUSION: These data suggest that acute heat exposure induces a cross-tolerance effect such that the pressor response to a voluntary hypoxic apnea is reduced. Acute heat exposure could improve hypertension in adults with obstructive sleep apnea, secondary to altered chemoreflex function and sympathetic neural control, and provide additional therapeutic options for this population to improve cardiovascular health
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