4,000 research outputs found
Radioactive method enables determination of surface areas rapidly and accurately
Radioactive krypton adsorption technique is used to determine the surface area of more than one sample of material simultaneously
Soleus H-reflex Excitability Changes in Response to Sinusoidal Hip Stretches in the Injured Human Spinal Cord
Imposed static hip stretches substantially modulate the soleus H-reflex in people with an intact or injured spinal cord while stretch of the hip flexors affect the walking pattern in lower vertebrates and humans. The aim of this study was to assess the effects of dynamic hip stretches on the soleus H-reflex in supine spinal cord injured (SCI) subjects. Sinusoidal movements were imposed on the right hip joint at 0.2 Hz by a Biodex system. H-reflexes from the soleus muscle were recorded as the leg moved in flexion or extension. Stimuli were sent only once in every hip movement cycle that each lasted 5 s. Torque responses were recorded at the hip, knee, and ankle joints. A hip phase-dependent soleus H-reflex modulation was present in all subjects. The reflex was facilitated during hip extension and suppressed during hip flexion. There were no significant differences in pre- or post-stimulus soleus background activity between the two conditions. Oscillatory responses were present as the hip was maximally flexed. Sinusoidal hip stretches modulated the soleus H-reflex in a manner similar to that previously observed following static hip stretches. The amount of reflex facilitation depended on the angle of hip extension. Further research is needed on the afferent control of spinal reflex pathways in health and disease in order to better understand the neural control of movement in humans. This will aid in the development of rehabilitation strategies to restore motor function in these patients
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The effect of rearing system and cooking method on the carnosine and anserine content of poultry and game meat
Poultry meat has been shown to be a rich source of carnosine and anserine (CRC) but little is known of the effects of bird species and the system under which it is reared have on the concentrations of CRC. Retail samples of breast meat from conventional chicken, free range chicken and pheasant, and breast meat from wild caught pheasant were procured and subjected to five different cooking methods: frying, grilling, boiling, microwaving and roasting. CRC were greater in uncooked pheasant than chicken (P< 0.05) and greater in free range than conventionally reared chicken (P<0.05). There were no differences in CRC between retail and wild caught pheasant. Cooking method affected CRC content; boiling and microwaving resulted in lower CRC contents than grilling, roasting or frying (P < 0.05). Pheasant is a richer source of CRC than conventionally reared chicken, although free range chicken produces meat of similar CRC content to pheasant
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Comparison of different dietary sources of n-3 polyunsaturated fatty acids on immune response in broiler chickens
The study aims to research the effects of varied dietary sources of n-3 polyunsaturated fatty acids (PUFA) on the immune response in broiler chickens with stress on natural killer (NK) cell activity. Diets supplemented with one of the four sources of n-3 PUFA: linseed oil-, echium oil-, fish oil (FO) or algal biomass-enriched diets at levels of 18, 18, 50 and 15 g/kg fresh weight, were provided for one-d-old male Ross 308 broilers, totaling 340 in number, until they were slaughtered. The analyses included total lipid profile using gas chromatography (GC) for plasma, spleen, thymus, and blood. Additionally, NK cell activity and cell proliferation were investigated for thymocytes and splenocytes. The results indicated that the source of n-3 PUFA had a strong influence on fatty acid composition across all tissues. NK activity was highest in splenocytes and PBMCs from broilers fed linseed oil, followed by those fed algal biomass or echium oil, and lowest for those from broilers fed FO. The proliferative response of lymphocytes from algal biomass-fed chickens tended to be the highest, followed by those fed linseed oil in most cases. Lymphocytes from chickens fed fish oil showed the lowest proliferative response. These results could mean that a docosahexaenoic acid (DHA)-rich algal product might enrich chicken meat with n-3 PUFA without significant damaging effects on chicken immunity
Modulation of Stretch Reflexes of the Finger Flexors by Sensory Feedback from the Proximal Upper Limb Poststroke
Neural coupling of proximal and distal upper limb segments may have functional implications in the recovery of hemiparesis after stroke. The goal of the present study was to investigate whether the stretch reflex response magnitude of spastic finger flexor muscles poststroke is influenced by sensory input from the shoulder and the elbow and whether reflex coupling of muscles throughout the upper limb is altered in spastic stroke survivors. Through imposed extension of the metacarpophalangeal (MCP) joints, stretch of the relaxed finger flexors of the four fingers was imposed in 10 relaxed stroke subjects under different conditions of proximal sensory input, namely static arm posture (3 different shoulder/elbow postures) and electrical stimulation (surface stimulation of biceps brachii or triceps brachii, or none). Fast (300°/s) imposed stretch elicited stretch reflex flexion torque at the MCP joints and reflex electromyographic (EMG) activity in flexor digitorum superficialis. Both measures were greatest in an arm posture of 90° of elbow flexion and neutral shoulder position. Biceps stimulation resulted in greater MCP stretch reflex flexion torque. Fast imposed stretch also elicited reflex EMG activity in nonstretched heteronymous upper limb muscles, both proximal and distal. These results suggest that in the spastic hemiparetic upper limb poststroke, sensorimotor coupling of proximal and distal upper limb segments is involved in both the increased stretch reflex response of the finger flexors and an increased reflex coupling of heteronymous muscles. Both phenomena may be mediated through changes poststroke in the spinal reflex circuits and/or in the descending influence of supraspinal pathways
Scientifically Defensible and Measurable Anti-Phishing Training
Problem: How can the effectiveness of a phishing attack be quantified and/or measured?
Applications: This project will provide a resource for Idaho National Labs to quantitavely evaluate the effectiveness of their security awareness program in regards to phishing attacks. In turn, it will aid them in hardening the human element of security at the research facility.
Approach: Our approach is to construct a fully functional phishing system where we can craft phishing emails, send emails, and place links that point to our web application. We hope to use this system to conduct an anonymous and non-malicious experiment. This data will assist in the design and implementation of the algorithm that will evaluate the relative effectiveness of a phishing email.
Interim Results: At this point in time we have have started the experimental approval process and developed a functioning phishing system to use in our experiment. We have created the framework in which to construct our algorithm.
Anticipated Results: Next Semester we plan to have a fully functioning phishing email evaluation algorithm. In addition are trying to run a live phishing study at VCU and if it is approved, itwill provide valuable data on the accuracy of our algorithm.https://scholarscompass.vcu.edu/capstone/1027/thumbnail.jp
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A systematic review of policy approaches to dairy sector Greenhouse Gas (GHG) emission reduction
The dairy sector is a significant source of anthropogenic greenhouse gas (GHG) emissions. The increasingly robust emission inventories allow researchers to consider mitigation. However, there is a gap in knowledge regarding the extent to which mitigation research has been implemented as policy. The authors undertook a systematic a review of national-level dairy policy of 23 countries broadly following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocols. The aim of the study was to identify international trends in dairy sector GHG emission reduction policy. Sampled countries included the 12 countries with the highest quantity of dairy sector enteric methane emission and 11 Annex I countries with the largest number of dairy cattle per capita. A total of 34 documents were collated containing 62 policies across five themes. Themes included: nutrition, manure, health, breeding and management. Thirty-one policies were identified for both the high emission nations and Annex I nations with the largest number of dairy cattle per capita. Nutrition based interventions account for 36% (n=11) of all policies identified for high emitting nations. Manure based interventions account for 48% (n=15) of all policies identified for Annex I nations with the largest number of dairy cattle per capita. Across the sample, policymakers favoured manure management strategies (n=24), particularly anaerobic digestion which accounted for 21% (n=13) of all identified policies. Nutrition based mitigation strategies were also preferred (n=17). Policies aimed at reducing sector size were largely ignored (n=4). The results indicate that significant mitigation is unlikely as manure emissions are only a small portion of total dairy sector emissions. The study concludes that policymakers are selecting the less politically sensitive mitigation strategies at the cost of emission reduction
Plasma electrons above Saturn's main rings: CAPS observations
We present observations of thermal ( similar to 0.6 - 100eV) electrons observed near Saturn's main rings during Cassini's Saturn Orbit Insertion (SOI) on 1 July 2004. We find that the intensity of electrons is broadly anticorrelated with the ring optical depth at the magnetic footprint of the field line joining the spacecraft to the rings. We see enhancements corresponding to the Cassini division and Encke gap. We suggest that some of the electrons are generated by photoemission from ring particle surfaces on the illuminated side of the rings, the far side from the spacecraft. Structure in the energy spectrum over the Cassini division and A-ring may be related to photoelectron emission followed by acceleration, or, more likely, due to photoelectron production in the ring atmosphere or ionosphere
The Hector Mine, California, Earthquake of 16 October 1999: Introduction to the Special Issue
The Hector Mine, California, earthquake (M_w 7.1) struck the Mojave Desert at 09:46 UTC, 16 October 1999. The earthquake occurred approximately 55 km northwest of the town of Twentynine Palms, California, and about 200 km east-northeast of Los Angeles (Fig. 1). The shock was widely felt throughout southern California, southern Nevada, western Arizona, and northernmost Baja California, Mexico. The Hector Mine earthquake, like the M_w 7.3 Landers earthquake seven years earlier, was associated with fault rupture in the eastern California shear zone (ECSZ) (Fig. 1), which is an approximately 80-km-wide zone of deformation that accommodates about 24% of the relative Pacific–North American plate motion (Sauber et al., 1986, 1994; Dokka and Travis, 1990; Savage et al., 1990, 2001; Gan et al., 2000; Miller et al., 2001). A block diagram highlighting some of the basic aspects of the Hector Mine earthquake is presented in Figure 2. A preliminary summary of the Hector Mine earthquake, its effects, and the response of the geoscience community is presented by Scientists from the U.S. Geological Survey; Southern California Earthquake Center, and California Division of Mines and Geology (USGS, SCEC, and CDMG, 2000)
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A deterministic evaluation of heat stress mitigation and feed cost under climate change within the smallholder dairy sector
In the global South, dairying is often promoted as a means of poverty alleviation. Yet, under conditions of climate warming, little is known regarding the ability of small-scale dairy producers to maintain production and/or the robustness of possible adaptation options in meeting the challenges presented, particularly heat stress. The authors created a simple, deterministic model to explore the influence of breed and heat stress relief options on smallholder dairy farmers in Odisha, India. Breeds included indigenous Indian (non-descript), low-grade Jersey crossbreed and high-grade Jersey crossbreed. Relief strategies included providing shade, fanning and bathing. The impact of predicted critical global climate parameters, a 2°C and 4°C temperature rise were explored. A feed price scenario was modelled to illustrate the importance of feed in impact estimation. Feed costs were increased by 10% to 30%. Across the simulations, high-grade Jersey crossbreeds maintained higher milk yields, despite being the most sensitive to the negative effects of temperature. Low-capital relief strategies were the most effective at reducing heat stress impacts on household income. However, as feed costs increased the lower-grade Jersey crossbreed became the most profitable breed. The high-grade Jersey crossbreed was only marginally (4.64%) more profitable than the indigenous breed. The results demonstrate the importance of understanding the factors and practical trade-offs that underpin adaptation. The model also highlights the need for hot-climate dairying projects and programmes to consider animal genetic resources alongside environmentally sustainable adaptation measures for greatest poverty impact
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