703 research outputs found
Nonthermal Emission from Star-Forming Galaxies
The detections of high-energy gamma-ray emission from the nearby starburst
galaxies M82 & NGC253, and other local group galaxies, broaden our knowledge of
star-driven nonthermal processes and phenomena in non-AGN star-forming
galaxies. We review basic aspects of the related processes and their modeling
in starburst galaxies. Since these processes involve both energetic electrons
and protons accelerated by SN shocks, their respective radiative yields can be
used to explore the SN-particle-radiation connection. Specifically, the
relation between SN activity, energetic particles, and their radiative yields,
is assessed through respective measures of the particle energy density in
several star-forming galaxies. The deduced energy densities range from O(0.1)
eV/cm^3 in very quiet environments to O(100) eV/cm^3 in regions with very high
star-formation rates.Comment: 17 pages, 5 figures, to be published in Astrophysics and Space
Science Proceeding
Using a virtual environment to assess cognition in the elderly
YesEarly diagnosis of Alzheimer’s disease (AD) is essential if treatments are to be administered at an earlier point in time before neurons degenerate to a stage beyond repair. In order for early detection to occur tools used to detect the disorder must be sensitive to the earliest of cognitive impairments. Virtual reality (VR) technology offers opportunities to provide products which attempt to mimic daily life situations, as much as is possible, within the computational environment. This may be useful for the detection of cognitive difficulties. We develop a virtual simulation designed to assess visuospatial memory in order to investigate cognitive function in a group of healthy elderly participants and those with a mild cognitive impairment. Participants were required to guide themselves along a virtual path to reach a virtual destination which they were required to remember. The preliminary results indicate that this virtual simulation has the potential to be used for detection of early AD since significant correlations of scores on the virtual environment with existing neuropsychological tests were found. Furthermore, the test discriminated between healthy elderly participants and those with a mild cognitive impairment (MCI)
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F.J. Turner’s ‘frontier thesis’: the ruse of American ‘character'
American society was transformed by the expansion of capital Westward and the explosion in opportunities that ensued for land grabbing and agricultural and industrial investment. In Turner’s (1961) frontier thesis this was portrayed as resulting in the emergence of ‘the new man’ i.e. the fulfilment of American character. The frontier thesis is a neo-Darwinian contribution. It posits exceptionalism and transcendence as the keys to American character. The gene pool of the Americans, thriving in a new geographical and social environment, is depicted as achieving a higher level of development than the stratified societies of Old Europe. What the thesis ignores is the importance of orthodox Eurocentric strategies of colonization and land appropriation. Turner portrays pioneer/settler society as a heroic departure, but in many ways, it is a continuation of European precedents. Analogously, the proposition that the push West crystallized American character obscures the role of personality, especially in urban-industrial settings, in establishing the parameters of American life. Turner conceived of character as emerging from a struggle with the spatial frontier. But the struggles of personality with the social frontier of repression and establishment values is no less significant. The paper examines the tensions between character and personality by using some ideas developed by Carl Schmitt on the significance of ‘the opportunity’ in competitive advantage. The importance of the opportunity and personality in developing the American way of life are examined by the vaudeville and celebrity traditions. The exploitation of contingency for personal advantage, the use of melodrama to engineer social impact, the social validation of forthright behaviour are examined in the context of the careers of the film actress Mae West and the comedian Bob Hope
Dopamine neurons modulate neural encoding and expression of depression-related behaviour
Major depression is characterized by diverse debilitating symptoms that include hopelessness and anhedonia1. Dopamine neurons involved in reward and motivation are among many neural populations that have been hypothesized to be relevant, and certain antidepressant treatments, including medications and brain stimulation therapies, can influence the complex dopamine system. Until now it has not been possible to test this hypothesis directly, even in animal models, as existing therapeutic interventions are unable to specifically target dopamine neurons. Here we investigated directly the causal contributions of defined dopamine neurons to multidimensional depression-like phenotypes induced by chronic mild stress, by integrating behavioural, pharmacological, optogenetic and electrophysiological methods in freely moving rodents. We found that bidirectional control (inhibition or excitation) of specified midbrain dopamine neurons immediately and bidirectionally modulates (induces or relieves) multiple independent depression symptoms caused by chronic stress. By probing the circuit implementation of these effects, we observed that optogenetic recruitment of these dopamine neurons potently alters the neural encoding of depression-related behaviours in the downstream nucleus accumbens of freely moving rodents, suggesting that processes affecting depression symptoms may involve alterations in the neural encoding of action in limbic circuitry
Vegan diets : practical advice for athletes and exercisers.
With the growth of social media as a platform to share information, veganism is becoming more visible, and could be becoming more accepted in sports and in the health and fitness industry. However, to date, there appears to be a lack of literature that discusses how to manage vegan diets for athletic purposes. This article attempted to review literature in order to provide recommendations for how to construct a vegan diet for athletes and exercisers. While little data could be found in the sports nutrition literature specifically, it was revealed elsewhere that veganism creates challenges that need to be accounted for when designing a nutritious diet. This included the sufficiency of energy and protein; the adequacy of vitamin B12, iron, zinc, calcium, iodine and vitamin D; and the lack of the long-chain n-3 fatty acids EPA and DHA in most plant-based sources. However, via the strategic management of food and appropriate supplementation, it is the contention of this article that a nutritive vegan diet can be designed to achieve the dietary needs of most athletes satisfactorily. Further, it was suggested here that creatine and β-alanine supplementation might be of particular use to vegan athletes, owing to vegetarian diets promoting lower muscle creatine and lower muscle carnosine levels in consumers. Empirical research is needed to examine the effects of vegan diets in athletic populations however, especially if this movement grows in popularity, to ensure that the health and performance of athletic vegans is optimised in accordance with developments in sports nutrition knowledge
The relationship between processing speed and regional white matter volume in healthy young people
Processing speed is considered a key cognitive resource and it has a crucial role in all types of cognitive performance. Some researchers have hypothesised the importance of white matter integrity in the brain for processing speed; however, the relationship at the whole-brain level between white matter volume (WMV) and processing speed relevant to the modality or problem used in the task has never been clearly evaluated in healthy people. In this study, we used various tests of processing speed and Voxel-Based Morphometry (VBM) analyses, it is involves a voxel-wise comparison of the local volume of gray and white, to assess the relationship between processing speed and regional WMV (rWMV). We examined the association between processing speed and WMV in 887 healthy young adults (504 men and 383 women; mean age, 20.7 years, SD, 1.85). We performed three different multiple regression analyses: we evaluated rWMV associated with individual differences in the simple processing speed task, word–colour and colour–word tasks (processing speed tasks with words) and the simple arithmetic task, after adjusting for age and sex. The results showed a positive relationship at the whole-brain level between rWMV and processing speed performance. In contrast, the processing speed performance did not correlate with rWMV in any of the regions examined. Our results support the idea that WMV is associated globally with processing speed performance regardless of the type of processing speed task
Sustainable drainage system site assessment method using urban ecosystem services
The United Kingdom's recently updated approach to sustainable drainage enhanced biodiversity and amenity objectives by incorporating the ecosystem approach and the
ecosystem services concept. However, cost-effective and reliable methods to appraise the biodiversity and amenity values of potential sustainable drainage system (SuDS)sites and their surrounding areas are still lacking, as is a method to enable designers to distinguish and link the amenity and biodiversity benefits that SuDS schemes can offer. In this paper, therefore, the authors propose two ecosystem services- and disservices-based methods (i.e. vegetation structure cover-abundance examination and cultural ecosystem services and disservices variables appraisal) to aid SuDS designers to distinguish and link amenity and biodiversity benefits, and allow initial site
assessments to be performed in a cost-effective and reliable fashion. Forty-nine representative sites within Greater Manchester were selected to test the two methods.
Amenity and biodiversity were successfully assessed and habitat for species, carbon sequestration, recreation and education ecosystem services scores were produced,which will support SuDS retrofit design decision-making. Large vegetated SuDS sites with permanent aquatic features were found to be most capable of enhancing biodiversity- and amenity-related ecosystem services. Habitat for species and
recreation ecosystem services were also found to be positively linked to each other. Finally, waste bins on site were found to help reduce dog faeces and litter coverage. Overall, the findings presented here enable future SuDS retrofit designs to be more wildlife friendly and socially inclusive
Cytoreductive Debulking Surgery Among Patients with Neuroendocrine Liver Metastasis: a Multi-Institutional Analysis
BACKGROUND:
Management of neuroendocrine liver metastasis (NELM) in the setting of unresectable disease is poorly defined and the role of debulking remains controversial. The objective of the current study was to define outcomes following non-curative intent liver-directed therapy (debulking) among patients with NELM.
METHODS:
612 patients were identified who underwent liver-directed therapy of NELM from a multi-institutional database. Outcomes were stratified according to curative (R0/R1) versus non-curative ≥ 80% debulking (R2).
RESULTS:
179 (29.2%) patients had an R2/debulking procedure. Patients undergoing debulking more commonly had more aggressive high-grade tumors (R0/R1: 12.8% vs. R2: 35.0%; P < 0.001) or liver disease burden that was bilateral (R0/R1: 52.8% vs. R2: 75.6%; P < 0.001). After a median follow-up of 51 months, median (R0/R1: not reached vs. R2: 87 months; P < 0.001) and 5-year survival (R0/R1: 85.2% vs. R2: 60.7%; P < 0.001) was higher among patients who underwent an R0/R1 resection compared with patients who underwent a debulking operation. Among patients with ≥50% NELM liver involvement, median and 5-year survival following debulking was 55.4 months and 40.6%, respectively.
CONCLUSION:
Debulking operations for NELM provided reasonable long-term survival. Hepatic debulking for patients with NELM is a reasonable therapeutic option for patients with grossly unresectable disease that may provide a survival benefit.info:eu-repo/semantics/publishedVersio
Hepatic Resection for Non-Functional Neuroendocrine Liver Metastasis: Does the Presence of Unresected Primary Tumor or Extrahepatic Metastatic Disease Matter?
OBJECTIVES:
The objective of this study was to assess the impact of unresected primary tumor, as well as extrahepatic metastasis, on the long-term prognosis of patients undergoing hepatic resection for non-functional neuroendocrine liver metastasis (NF-NELM).
METHODS:
Patients who underwent hepatic resection for NF-NELM were identified from a multi-institutional database. Data on clinical and pathological details, as well as the long-term overall survival (OS) were obtained and compared. Propensity score matching was performed to generate matched pairs of patients.
RESULTS:
Among the 332 patients with NF-NELM, 281 (84.6%) underwent primary tumor resection, while 51 (15.4%) did not. Patients who underwent primary resection were more likely to have a pancreatic primary and metachronous NELM. The long-term OS of patients who did and did not have the primary neuroendocrine tumor (NET) resected was comparable on both unmatched (10-year survival rate 66.8% vs. 54.0%, p = 0.192) and matched (10-year survival rate 75.7% vs. 60.4%, p = 0.271) analyses. In contrast, patients with NF-NELM and extrahepatic metastasis had a worse OS following resection compared with patients who had intrahepatic-only metastasis on unmatched (10-year survival rate 37.5% vs. 69.3%, p = 0.002) and matched (10-year survival rate 37.5% vs. 86.3%, p = 0.011) analyses. On multivariable analysis, while resection of the primary NET was not associated with OS (hazard ratio [HR] 0.7, 95% confidence interval [CI] 0.4-1.2, p = 0.195), the presence of extrahepatic metastasis was independently associated with long-term risk of death (HR 3.9, 95% CI 1.7-9.2, p = 0.002).
CONCLUSIONS:
While surgery should be considered for patients with NF-NELM who have an unresectable primary tumor, operative resection of NF-NELM may not be as beneficial in patients with extrahepatic disease.info:eu-repo/semantics/publishedVersio
Successful recanalization for internal carotid artery occlusion with persistent primitive trigeminal artery manifesting only as ischemia of the posterior circulation
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