1,526 research outputs found
Inclusivity Through Documentation: Using Gestalt Principles and Plain Language to Create Effective Documents
Usable design makes documents easier to use and lends credibility to the document creators. A few simple tips, such as following Gestalt principles and using plain language, can improve document usability. Workshop attendees will apply knowledge learned through interactive document redesign activities
A Thermodynamic Analysis of an Intense North American Arctic Air Mass
Northwestern Canada is a genesis region of arctic air masses often considered to be formed primarily through radiative processes. However, the details of their life cycle are poorly understood. This paper examines the formation, maintenance, and dissipation of an intense and long-lived arctic air mass, using a thermodynamic budget analysis.
The airmass formation is characterized by a deep-layer, multistage process that begins with snow falling into a nascent air mass. Radiative cooling from cloud tops begins the process. After the snow abates and clear skies are observed, the surface temperature drops rapidly, aided by the high emissivity of fresh snow cover, falling 178C in two days, creating an intense but shallow temperature inversion. Once the surface temperature falls below the frost point, ice crystals form. Afterward, although the surface temperature remains constant, the height of the inversion rises, as radiative cooling at the top of the ice fog layer decreases temperatures.
During the maintenance phase, a cold-air damming structure is present with an anticyclone in the lee of the Canadian Rockies, low pressure in the Gulf of Alaska, and an intense baroclinic zone parallel to the mountains, separating warmer maritime air from colder continental air. The air mass persists for 12 days, undergoing several cycles of deep-layer weakening and intensification
Environmental and Ecological Benefits and Impacts of Oyster Aquaculture Chesapeake Bay, Virginia, USA
To better quantify the ecological benefits and impacts of oyster aquaculture, we sampled water quality, sediment quality, benthic macrofaunal communities and oysters at four oyster aquaculture sites located on the western shore of Chesapeake Bay in Virginia, USA. At each site, we collected samples from within the footprint of the aquaculture cages and from nearby areas with similar physical and environmental conditions but far enough away to be minimally influenced by aquaculture operations. Data collected from the water column included chlorophyll concentrations, turbidity, pH, dissolved oxygen concentrations, light attenuation, particle concentration, median particle size, total suspended solids and their organic content, and dissolved nutrient concentrations. Sediment and macrofauna community data collected included sediment grain size and organic content and macrofauna identity, abundance, biomass and species richness. In addition to assessing the potential impacts of oyster aquaculture on the water column and benthos, we also assessed differences in the oysters harvested Environmental and ecological benefits and impacts of oyster aquaculture at each site and estimated the total amount of nitrogen and phosphorus harvested at each site. Differences in water quality, sediment quality, and macrofauna community structure between areas within and outside the farm footprint were rare and of small magnitude and varying direction (i.e. negative versus positive impact) when they did occur. Aquaculture sites varied by an order of magnitude in size, annual harvest and harvest per unit area. They also varied by an order of magnitude in the total amount of nitrogen (N) and phosphorus (P) harvested per unit area. In contrast to the negative environmental impacts associated with other forms of animal protein production for human consumption, oyster harvest from aquaculture sites studied here resulted in the removal of 21-372 lbs. of N and 3-49lbs of P per farm per year
Minimal effects of oyster aquaculture on local water quality: Examples from southern Chesapeake Bay
As the oyster aquaculture industry grows and becomes incorporated into management practices, it is important to understand its effects on local environments. This study investigated how water quality and hydrodynamics varied among farms as well as inside versus outside the extent of caged grow-out areas located in southern Chesapeake Bay. Current speed and water quality variables (chlorophyll-a fluorescence, turbidity, and dissolved oxygen) were measured along multiple transects within and adjacent to four oyster farms during two seasons. At the scale of individual aquaculture sites, we were able to detect statistically significant differences in current speed and water quality variables between the areas inside and outside the farms. However, the magnitudes of the water quality differences were minor. Differences between sites and between seasons for water quality variables were typically an order of magnitude greater than those observed within each site (i.e. inside and outside the farm footprint). The relatively small effect of the presence of oysters on water quality is likely attributable to a combination of high background variability, relatively high flushing rates, relatively low oyster density, and small farm footprints. Minimal impacts overall suggest that low-density oyster farms located in adequately-flushed areas are unlikely to negatively impact local water quality.
Associated datafiles available at: https://doi.org/10.25773/wwva-tz1
A Data Repository for Minimal Effects of Oyster Aquaculture on Water Quality: Examples from Southern Chesapeake Bay
The objective of this study was to quantify the effects of oyster aquaculture on water quality, sediment quality, and hydrodynamics at select sites in southern Chesapeake Bay. To this end, information was gathered over the course of approximately one year from February 2017 to October 2017 at four operating commercial farms. Farms were sampled during spring, summer, and fall seasons during times of oyster filtration activity when temperatures were greater than 10oC. Aquaculture sites differed in environmental setting, in terms of their exposure to waves and resulting sediment characteristics. Sites had mesohaline salinities (ranging from 15-22 psu) and mean water depths of ~1 m (ranging from 0.5 to 2 m depending on distance from shore and tidal stage). Site characterization was conducted at each oyster farm using standard sedimentological measurements with a PONAR grab to map sediment characteristics throughout the extent of each oyster farm and surrounding area.
Following site characterization, hydrographic, water clarity, and water quality data were collected using high frequency spatial water quality mapping of transects on a moving vessel and an instrumented profiler at discrete point samples. On high frequency spatial water quality mapping (transect) cruises, the vessel was driven along 10-30 transects including approximately half inside and half outside the extent of cages while vessel-mounted instruments sampled continuously. On discrete point sample (instrumented profiler) cruises, data were collected at five designated stations along a central transect of the farms with three stations within the extent of cages and two stations outside. The two smallest oyster farms were sampled only during Summer 2017. Two of the larger oyster farms were sampled during Summer and Fall 2017. Additionally, during Summer 2017 at Windmill Point, a stationary upward facing acoustic Doppler profiler collected data over one month
Environmental and ecological benefits and impacts of oyster aquaculture: Addendum
The data described in this addendum are provided to enhance the resolution and/or expand the temporal scope of the information already provided in the final report (Kellogg et al. 2018). High-resolution water quality transect data were collected at all four sites in Summer 2017, at White Stone (Windmill Point site) and Lynnhaven River in Fall 2017, and at White Stone (North Point site) in Spring 2018. During each sampling period, data were collected from multiple transects through and outside of each farm. Resulting data were detrended as needed based on temporal and salinity-related patterns found in data collected outside the farm footprint. Comparison of the resulting data from inside and outside the farm identified significant differences between water quality inside the farm footprint and outside for the majority of site x season combinations for all parameters. However, differences were consistently small enough to have no biologically significant impact, positive or negative, on farm-scale water quality.
Benthic macrofaunal communities inside and outside the farms were assessed at White Stone’s Windmill Point site and at the Lynnhaven River site in Fall 2017 and White Stone’s North Point site in Spring 2018. Data on species richness, macrofauna abundance, and macrofauna biomass were compared between samples taken inside the farm footprint and outside the farm footprint for all site x season combinations. These data were compared to data previously reported from Summer 2017 collected at all four aquaculture sites. Overall, patterns in species richness and macrofauna abundance were not consistent across seasons within site, across sites within seasons or within gear type. With the exception of one of the farm sites studied, there was a trend towards increased macrofauna biomass inside the footprint of aquaculture farms. This pattern is consistent with the assumption that food for benthic macrofauna at these sites is enhanced by oyster biodeposition. Overall, we found no biologically significant negative impacts on macrofaunal communities inside aquaculture farms and some evidence that suggests a possible positive impact on benthic macrofauna production
Does characterising patterns of multimorbidity in stroke matter for developing collaborative care approaches in primary care?
Stroke and transient ischaemic attack (TIA) remain leading causes of mortality and morbidity globally. Although mortality rates have been in decline, the number of people affected by stroke has risen. These patients have a range of long-term needs and often present to primary care. Furthermore, many of these patients have multimorbidities which increase the complexity of their healthcare. Long-term impacts from stroke/TIA along with care needs for other morbidities can be challenging to address because care can involve different healthcare professionals, both specialist and generalist. In the ideal model of care, such professionals would work collaboratively to provide care. Despite the commonality of multimorbidity in stroke/TIA, gaps in the literature remain, particularly limited knowledge of pairings or clusters of comorbid conditions and the extent to which these are interrelated. Moreover, integrated care practices are less well understood and remain variable in practice. This article argues that it is important to understand (through research) patterns of multimorbidity, including number, common clusters and types of comorbidities, and current interprofessional practice to inform future directions to improve long-term care.This article received no specific grant from any funding agency, commercial or not-for-profit sectors. JM is an National Institute for Health Research (NIHR) Senior Investigator
Sharing Privacy-sensitive Access to Neuroimaging and Genetics Data: A Review and Preliminary Validation
The growth of data sharing initiatives for neuroimaging and genomics represents an exciting opportunity to confront the “small N” problem that plagues contemporary neuroimaging studies while further understanding the role genetic markers play in the function of the brain. When it is possible, open data sharing provides the most benefits. However, some data cannot be shared at all due to privacy concerns and/or risk of re-identification. Sharing other data sets is hampered by the proliferation of complex data use agreements (DUAs) which preclude truly automated data mining. These DUAs arise because of concerns about the privacy and confidentiality for subjects; though many do permit direct access to data, they often require a cumbersome approval process that can take months. An alternative approach is to only share data derivatives such as statistical summaries—the challenges here are to reformulate computational methods to quantify the privacy risks associated with sharing the results of those computations. For example, a derived map of gray matter is often as identifiable as a fingerprint. Thus alternative approaches to accessing data are needed. This paper reviews the relevant literature on differential privacy, a framework for measuring and tracking privacy loss in these settings, and demonstrates the feasibility of using this framework to calculate statistics on data distributed at many sites while still providing privacy
Bio-processing of macroalgae Palmaria palmata:Metabolite fractionation from pressed fresh material and ensiling considerations for long-term storage
Functional MRI Evaluation of Multiple Neural Networks Underlying Auditory Verbal Hallucinations in Schizophrenia Spectrum Disorders.
Functional MRI studies have identified a distributed set of brain activations to be asso ciated with auditory verbal hallucinations (AVH). However, very little is known about how activated brain regions may be linked together into AVH-generating networks. Fifteen volunteers with schizophrenia or schizoaffective disorder pressed buttons to indicate onset and offset of AVH during fMRI scanning. When a general linear model was used to compare blood oxygenation level dependence signals during periods in which subjects indicated that they were versus were not experiencing AVH ( AVH-on versus AVH-off ), it revealed AVH-related activity in bilateral inferior frontal and superior temporal regions; the right middle temporal gyrus; and the left insula, supramarginal gyrus, inferior parietal lobule, and extranuclear white matter. In an effort to identify AVH-related networks, the raw data were also processed using independent component analyses (ICAs). Four ICA components were spatially consistent with an a priori network framework based upon published meta-analyses of imaging correlates of AVH. Of these four components, only a network involving bilateral auditory cortices and posterior receptive language areas was significantly and positively correlated to the pattern of AVH-on versus AVH-off. The ICA also identified two additional networks (occipital-temporal and medial prefrontal), not fully matching the meta-analysis framework, but nevertheless containing nodes reported as active in some studies of AVH. Both networks showed significant AVH-related profiles, but both were most active during AVH-off periods. Overall, the data suggest that AVH generation requires specific and selective activation of auditory cortical and posterior language regions, perhaps coupled to a release of indirect influence by occipital and medial frontal structures
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