967 research outputs found
The effect of photoperiod on the regressive phase of the ovarian cycle of the lizard, Anolis carolinensis.
The effects of constant photoperiod (14 hours of light) and decreasing photoperiod (13-8 hours of light) on the regressive phase of the ovarian cycle of the lizard Anolis carolinensis were investigated. Changes in body, liver, ovary and oviduct weights were measured and microscopic examinations of several ovarian parameters were made. In both light regimens body and liver weights decreased over the first four weeks of the experiment but both increased at the sixth week. In addition, ovary weight was highly variable but exhibited a decreasing trend and oviduct weight decreased. There were decreases in the number of previtellogonic follicles and in the diameter of the largest previtelogenic follicles in anoles subjected to a decreasing photoperiod. There were no changes in these parameters in anoles kept at a constant photoperiod. On the basis of these data, decreasing photoperiod is proposed to be the environmental cue for regression in Anolis carolinesi
Central Command Rest and Recuperation Hub-to-Hub Airlift Network Analysis
The primary purpose of this research effort was to discover the efficiency and effectiveness of the historical hub-to-hub R&R airlift network. This study analyzed the hub-to-hub aircraft efficiency rates and introduced capacity changes in the airlift network with the use of Arena simulation to improve network performance. Furthermore, this study created simple heuristic options for the future airlift framework required to meet USCENTCOM\u27s forecasted R&R transportation demand under the premise of a CY11 country 1 drawdown and an upscale of combat and support forces within country 2. There were several important outcomes of this research effort. First, this study designed the future framework for R&R airlift passenger operations with a focus on leveraging simple heuristics to increase intertheater commercial aircraft utilization to 89.7 percent while also adding four additional weekly sorties in the strategic port to intratheater hub routes. As a result, this study demonstrated that passenger velocity at the strategic port could be increased by 20.6 hours on the average and 24.9 hours at the 90th percentile with a decrease in the transient passenger footprint at the strategic port by 215 passengers on the average. This transient passenger footprint reduction also opens up further opportunities for cost savings by contracting support personnel and facilities at the strategic port for future operations. Finally, this study found that the use of a simple heuristic could increase commercial aircraft seat utilization rates by approximately 10 percent yielding an estimated $26.5M in yearly savings in contract airlift
Qualitative investigation of the role of collaborative football and walking football groups in mental health recovery
Efforts to increase physical activity levels in people with serious mental health conditions are viewed as desirable but little is known about how best to support this group to engage in exercise over extended periods. From a personal recovery perspective, the dominant paradigm in current mental health service delivery, one promising route involves participation with, rather than administration to or supervision of, mental health service users in team sports, usually football, in order to foster sharing of common interests and experiences. We aimed to explore the factors underlying the success of four collaborative mental health football (soccer) projects and the role played by football in mental health care delivery and in personal recovery. We held semi-structured focus groups with service user (n = 18) and staff (n = 7) participants from four football groups (two 'walking' football and two regular football) in two geographical National Health Service Boards in Scotland. Thematic analysis revealed that, central to success, were perceived relational, and personal and physical recovery-related benefits; competition and collaboration-related aspects were important drivers of interest in and commitment to the groups. Further, participants identified barriers to and concerns for continued success; specifically, they expressed that they need more explicit support from senior management. The clear emerging message was that collaborative football groups were perceived by participants as a conduit for recovery and an important aspect of mental healthcare delivery. Playing football was associated with a sense of wellbeing, and enhanced relationships between service users and staff
Evaluation of a rehabilitation support service after acute stroke: Feasibility and patient/carer benefit
Background: Stroke survivors returning home after discharge from hospital and their carers require support to meet their rehabilitation needs (independence in Activities of Daily Living, exercise, psychosocial support). Voluntary or charitable care providers may be able to address some of these needs.
Objective: To explore the feasibility of delivering and evaluating enhanced support to stroke survivors and their carers, with a Rehabilitation Support Worker (RSW).
Methods: 16 consecutive stroke survivors and their carers were included. All participants received usual hospital care. Seven of these patients and their carers were also allocated an RSW from a charitable care provider. The RSW accompanied therapy training sessions with the patient, carer and therapist in hospital. On discharge, the RSW visited the patient and carer at home over the initial 6 week post-discharge period to support them in practising rehabilitation skills. Patient function (Barthel Index) and patient/carer confidence were independently assessed at discharge (Week 0). The above assessments and patient/carer mood (GHQ-12) and Carer Giver Strain were also assessed at Weeks 1, 6 and 12. RSWs were interviewed for their views about the service.
Results: Participants’ functional ability at Week 1 post-discharge was significantly higher in the RSW group. At 6 and 12 weeks post-discharge, functional ability was not significantly different between groups. Carers in the intervention group were less confident at all time points, however, this was not significant. There was no significant effect on carer strain or well-being. Interviews with RSWs highlighted areas of their training that could be enhanced and the need for greater clarity as to their role.
Conclusions: The results showed that a definitive trial of rehabilitation support is feasible. A number of obstacles however would need to be overcome including: difficulty in identifying suitable patients, clarity of the RSW role, and appropriate training content
Extracting fish abundance indices from recreational fishing competition data
Over-exploited fisheries result in global economic losses and can lead to the degradation of marine ecosystems. Commercial and recreational fisheries have grown substantially over the past decades placing fish stocks under increasing pressure. Fisheries management aims to conserve and restore stocks to economically and environmentally sustainable levels. Stock assessments are mostly based on analyses of fishery-dependent data, however, this practice often neglects uneconomically important species, making ecosystem approaches to fisheries management challenging. Competitive recreational angling has the potential to provide accurate and consistent records of catch and effort data for a variety of unassessed fish species as well as data for currently assessed commercial species, but without the market influence on targeting. The data from five boat based recreational competitions in the Western Cape were studied. Records for the competitions varied in length with the longest dataset from running from 1994 to 2014, and the shortest from 2003 to 2014. The competitions were divided into three inshore and two offshore groups with each targeting different assemblages of fish. In total 38 species of teleost were caught, but at least 90% of the total catch for each competition was comprised of seven species or less. Catch composition was determined for each competition and the standardised catch per unit effort (CPUE) of the ten most abundant species across the competitions were assessed. CPUE trends for red roman, snoek and geelbek were comparable to commercial fishery-dependent CPUE data. The targeting of specific species in the multi-species fishery noticeably influenced CPUE values. Catch limits resulted in lower estimations of the CPUE for snoek, and potentially for red stump nose. Boat based competition data is accurate and consistent enough for the extraction of abundance indices for certain species. Further work on these data may involve the standardisation of CPUE values to account for targeting in the multi-species fishery. With a large number of boat based competitive anglers in the country, there is a scope for using these data for stock assessments, either as stand-alone data sources, or as an adjunct to well-established commercial catch time-series
Assessing the Potential to Detect Oil Spills In and Under Snow Using Airborne Ground-Penetrating Radar
With recent increased interest in oil and gas exploration and development in the Arctic comes increased potential for an accidental hydrocarbon release into the cryosphere, including within and at the base of snow. There is a critical need to develop effective and reliable methods for detecting such spills. Numerical modeling shows that ground-penetrating radar (GPR) is sensitive to the presence of oil in the snow pack over a broad range of snow densities and oil types. Oil spills from the surface drain through the snow by the mechanisms of unsaturated flow and form geometrically complex distributions that are controlled by snow stratigraphy. These complex distributions generate an irregular pattern of radar reflections that can be differentiated from natural snow stratigraphy, but in many cases, interpretation will not be straightforward. Oil located at the base of the snow tends to reduce the impedance contrast with the underlying ice or soil substrate resulting in anomalously low-amplitude radar reflections. Results of a controlled field experiment using a helicopter- borne, 1000-MHz GPR system showed that a 2-cm-thick oil film trapped between snow and sea ice was detected based on a 51% decrease in reflection strength. This is the first reported test of GPR for the problem of oil detection in and under snow. Results indicate that GPR has the potential to become a robust tool that can substantially improve oil spill characterization and remediation
Locating Oil Spills Under Sea Ice Using Ground-Penetrating Radar
The accelerating level of interest in arctic oil and gas exploration was demonstrated in the overwhelming response to recent lease sales in the Alaskan OCS region. As development increases, the potential for accidental oil spills in the arctic marine environment increases. The need for reliable systems to detect oil trapped in a range of ice conditions remains at the forefront of continued efforts to improve response to ocean spills
Pedestrian detection for underground mine vehicles using thermal imaging
Vehicle accidents are one of the major causes of deaths in South African un-
derground mines. A computer vision-based pedestrian detection and track-
ing system is presented in this research that will assist locomotive drivers
in operating their vehicles safer. The detection and tracking system uses a
combination of thermal and three-dimensional (3D) imagery for the detec-
tion and tracking of people. The developed system uses a segment-classify-
track methodology which eliminates computationally expensive multi-scale
classi cation. A minimum error thresholding algorithm for segmentation is
shown to be e ective in a wide range of environments with temperature up to
26 C and in a 1000 m deep mine. The classi er uses a principle component
analysis and support vector classi er to achieve a 95% accuracy and 97%
speci city in classifying the segmented images. It is shown that each detec-
tion is not independent of the previous but the probability of missing two
detections in a row is 0.6%, which is considered acceptably low. The tracker
uses the Kinect's structured-light 3D sensor for tracking the identi ed peo-
ple. It is shown that the useful range of the Kinect is insu cient to provide
timeous warning of a collision. The error in the Kinect depth, measurements
increases quadratically with depth resulting in very noisy velocity estimates
at longer ranges. The use of the Kinect for the tracker demonstrates the
principle of the tracker but due to budgetary constraints the replacement of
the Kinect with a long range sensor remains future work
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Of Mysid and Menidia: Sublethal Effects of Micro and Nanoplastics on Estuarine Indicator Species
Microplastics are widely distributed in aquatic environments. The term ‘microplastics’ encompasses a wide array of particles with unique polymer constituents, morphologies, and sources, such as automobile tire tread. Tire wear particles (TWP) can end up in waterways near densely populated municipalities, where they can interact with aquatic biota. Studying the impact of commonly detected synthetic particles such as TWP, across micro and nanoscopic sizes, on estuarine indicator species may tell us how these anthropogenic contaminants affect the entire ecosystem. This study investigated ingestion, growth, and behavioral responses of inland silversides (Menidia beryllina) and mysid shrimp (Americamysis bahia) when exposed to three concentrations of TWP (60, 6000, and 60,000 particles/mL which is equivalent to 0.0038, 0.0378 and 3.778 mg/L in mass concentration for micro size particles) at micro and nano size fractions with TWP leachate across 5-25 practical salinity unit (PSU) salinity gradient. Following exposures, M. beryllina and A. bahia had significantly altered swimming behaviors, such as freezing, in zone duration and total distance moved, that could lead to an increased risk of predation and foraging challenges in the wild. Both A. bahia and M. beryllina growth was reduced in a concentration dependent manner when exposed to micro TWP, whereas M. beryllina demonstrated reduced growth only when exposed to nano TWP. TWP internalization was observed in both taxa at 15 PSU. A. bahia and M. beryllina had significantly higher particle ingestion at 15 PSU following micro TWP exposure. The presence of adverse effects in M. beryllina (growth at micro TWP and behavior) and A. bahia (behavior) indicate that even at current environmental levels, which are expected to continue to increase, aquatic ecosystems are likely experiencing negative impacts from TWP pollution
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