2,653 research outputs found
Vascular Origins of BOLD and CBV fMRI Signals: Statistical Mapping and Histological Sections Compared
Comparison of 3T blood oxygenation level dependent (BOLD) and cerebral blood volume (CBV) activation maps to histological sections enables the spatial discrimination of functional magnetic resonance imaging (fMRI) signal changes into different vascular compartments. We use a standard gradient echo–echo planar imaging technique to measure BOLD signal changes in the somatosensory cortex in response to whisker stimulation. Corresponding changes in CBV were estimated following the infusion of a super-paramagnetic contrast agent. We imaged in a tangential imaging plane that covered the cortical surface. Images were associated with post mortem histological sections showing both the surface vasculature and cytochrome oxidase stained whisker barrel cortex. We found a significant BOLD signal change in the large draining veins which occurred in the absence of a corresponding CBV change. Results suggest that in the venous drainage system, ~3mm distant from the area of activity, there is a robust change in blood oxygen saturation with little or no volume change. CBV changes are localised over the somatosensory barrel cortex and overlying arterial supply, supporting the theory that CBV changes are greater in the arterial than in the venous vasculature. This work investigating BOLD signal and underlying hemodynamics provides more information on the vascular origins of these important neuroimaging signals
Blast injuries in children: a mixed-methods narrative review.
Background and significance. Blast injuries arising from high explosive weaponry is common in conflict areas. While blast injury characteristics are well recognised in the adults, there is a lack of consensus as to whether these characteristics translate to the paediatric population. Understanding blast injury patterns in this cohort is essential for providing appropriate provision of services and care for this vulnerable cohort. Methods. In this mixed-method review, original papers were screened for data pertaining to paediatric injuries following blasts. Information on demographics, morbidity and mortality and service requirements were evaluated. The papers were written and published in English from a range of international specialists in the field. Patient and public involvement statement: No patients or members of the public were involved in this review. Results. Children affected by blast injuries are predominantly male and their injuries arise from explosive remnants of war, particularly unexploded ordinance. Blasts show increased morbidity and mortality in younger children, while older children have injury patterns similar to adults. Head and burn injuries represent a significant cause of mortality in young children, while lower limb morbidity is reduced compared to adults. Children have a disproportionate requirement for both operative and non-operative service resources, and provisions for this burden are essential. Conclusions. Certain characteristics of paediatric injuries arising from blasts are distinct from that of the adult cohort, while the intensive demands on services highlights the importance of understanding the diverse injury patterns in order to optimise future service provisions in caring for this the child blast survivor
An Analysis of an Alternate-Year Walleye Fry Stocking Program in the Cedar River in Iowa
Year-class analysis of walleye, Stizostedion v. vitreum (Mitchill), taken by anglers in a portion of the Cedar River in Iowa indicated that alternate-year stocking of 3,500 fry per mile of river did not influence year-class abundance. Despite the short duration of the project, 1951-1958, a reasonably direct relationship between spring floods and spring air temperatures and year-class abundance was evident. Disparity in year-class abundance between samples taken 5 miles apart and within 3 months of each other, but by different methods (angling and chemical kill), indicates either a sampling selectivity or a relative discreteness or stability of portions of an assumed homogeneous population of river walleyes, or both
Language and geographical location influence the incidence of chronic cough in the Canadian Longitudinal Study on Aging
French speakers have a 4% lower incidence of chronic cough than English speakers in the CLSA, but English speakers from Quebec, Newfoundland and Labrador, and Nova Scotia also have a lower risk of developing chronic cough https://bit.ly/3qAd3M
Recommended from our members
Evaluation of dredged material proposed for ocean disposal from MOTBY
The National Park Service, US Department of the Interior requested U.S. Army Corps of Engineers/New York District (USACE-NYD) to evaluate sediments around the Military Ocean Terminal (MOTBY) in Bayonne, New Jersey for unconfined ocean disposal at the Mud Dump Site. Sediment samples were collected from MOTBY. Tests and analyses were conducted on MOTBY sediment core samples. The evaluation of proposed dredged material from MOTBY included grain size and total organic carbon (TOC) analyses and one acute toxicity test with the amphipod Ampelisca abdita. In addition to this benthic toxicity test, a bioaccumulation test (28-day exposure) was conducted
Breaking the Silence: Achieving a Positive Campus Climate for Diversity from the Staff Perspective
The purpose of this paper is to identify factors that create a positive climate for diversity and to demonstrate how these factors predict outcomes related to achieving a positive campus climate for diversity. Based on survey data collected from 437 staff members employed at a large, public, predominantly White university in the Midwest, results suggest that the institution’s ability to achieve a positive climate for diversity reflects not only the personal characteristics of the staff member (race, gender, education level, and age) but also their perceptions of their immediate work environment. Implications are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43633/1/11162_2004_Article_8152.pd
Evaluation of Dredged Material Proposed for Ocean Disposal from Port Chester, New York
Port Chester was one of seven waterways that the US Army Corps of Engineers-New York District requested the Battelle Marine Sciences Laboratory to sample and evaluate for dredging and disposal in March 1994. Tests and analyses were conducted on Port Chester sediment core samples. Because the Port Chester area is located on the border between New York and southeast Connecticut, its dredged material may also be considered for disposal at the Central Long Island Sound Disposal Site. The sediment evaluation consisted of bulk sediment chemical analyses, chemical analyses of site water and dredged material elutriate preparations, water-column and benthic acute toxicity tests, and bioaccumulation studies. Individual sediment core samples collected from Port Chester were analyzed for grain size, moisture content, and total organic carbon. In addition, sediment was analyzed for bulk density, specific gravity, metals, chlorinated pesticides, polychlorinated biphenyl congers, polynuclear aromatic hydrocarbons and 1,4-dichlorobenzene
Threats from the air: damselfly predation on diverse prey taxa
To understand the diversity and strength of predation in natural communities, researchers must quantify the total amount of prey species in the diet of predators. Metabarcoding approaches have allowed widespread characterization of predator diets with high taxonomic resolution. To determine the wider impacts of predators, researchers should combine DNA techniques with estimates of population size of predators using mark–release–recapture (MRR) methods, and with accurate metrics of food consumption by individuals. Herein, we estimate the scale of predation exerted by four damselfly species on diverse prey taxa within a well‐defined 12‐ha study area, resolving the prey species of individual damselflies, to what extent the diets of predatory species overlap, and which fraction of the main prey populations are consumed. We identify the taxonomic composition of diets using DNA metabarcoding and quantify damselfly population sizes by MRR. We also use predator‐specific estimates of consumption rates, and independent data on prey emergence rates to estimate the collective predation pressure summed over all prey taxa and specific to their main prey (non‐biting midges or chironomids) of the four damselfly species. The four damselfly species collectively consumed a prey mass equivalent to roughly 870 (95% CL 410–1,800) g, over 2 months. Each individual consumed 29%–66% (95% CL 9.4–123) of its body weight during its relatively short life span (2.1–4.7 days; 95% CL 0.74–7.9) in the focal population. This predation pressure was widely distributed across the local invertebrate prey community, including 4 classes, 19 orders and c. 140 genera. Different predator species showed extensive overlap in diets, with an average of 30% of prey shared by at least two predator species. Of the available prey individuals in the widely consumed family Chironomidae, only a relatively small proportion (0.76%; 95% CL 0.35%–1.61%) were consumed. Our synthesis of population sizes, per‐capita consumption rates and taxonomic distribution of diets identifies damselflies as a comparatively minor predator group of aerial insects. As the next step, we should add estimates of predation by larger odonate species, and experimental removal of odonates, thereby establishing the full impact of odonate predation on prey communities.Peer reviewe
- …