2,582 research outputs found
INDUSTRIAL DEVELOPMENT IN A DEPRESSED AREA: MALE-FEMALE DIFFERENCES IN ATTITUDES
Community/Rural/Urban Development,
HIPS DON’T LIE: ANALYZING FRONTAL PLANE KINEMATICS IN ADULTS OF VARYING AGES DURING STEP TASKS
M. Jain, K. Wiegand
Eastern Washington University, Cheney, WA
Aging is linked to reduced physical activity, which can lead to loss of strength and coordination. Previous research indicates older individuals display greater asymmetries and altered kinematic patterns in fundamental movements, which can contribute to injury risk. PURPOSE: Assess the relationships between age and frontal plane kinematics of the hip and knee during step-up and step-down tasks. METHODS: Five of 75 participants have completed the study thus far: 2 males and 3 females, age 42.8±15.4. Participants completed three single leg step-ups and step-downs on each limb from a 25 cm height while 2D frontal plane kinematics were recorded.
Following informed consent, markers were placed bilaterally on anterior and posterior landmarks of the lower extremity. Knee Valgus and hip drop angles were calculated from exported kinematic data. Average maximum and minimum values of the dominant limb were calculated across trials. Range of motion (ROM) for each angle was calculated as average minimum value minus average maximum value. The relationships between age and hip drop ROM, age and knee valgus ROM, and age and symmetry were assessed using bivariate correlations (α=0.05). RESULTS: Means and standard deviations are presented in Table 1. Initial findings indicate a strong positive correlation between age and contralateral hip drop (r=0.14, p\u3e0.05). No correlations between age and knee valgus (r=0.08, p\u3e0.05), age and hip drop symmetry (r=-0.21, p\u3e0.05) or age and knee valgus symmetry (r=-0.11, p\u3e0.05) were found.
CONCLUSION: Preliminary data observed increased age may be associated with risky frontal plane hip kinematics. Further testing on a broader age range and remaining participants is necessary.
Supported by the ACSM NW Student Research Award
THIGH MUSCLE INJURIES IN TRACK AND FIELD: PRELIMINARY HQR COMPARISON AND IMPLICATIONS FOR INJURY RISK ASSESSMENT
K. Wiegand, O. Buchholz
Eastern Washington University, Cheney, WA
Thigh muscle injuries are common in athletes, with the hamstrings to quadriceps strength ratio (HQR) considered a potential risk factor. While consensus is lacking on the predictive accuracy of HQR for injury occurrence, some studies suggest potential utility in monitoring injury and performance metrics. PURPOSE: To provide a preliminary comparison of HQR values among injured and uninjured track and field athletes. METHODS: Thirty male and female Division-I track and field athletes representing all events events participated in the study prior to the start of pre-season training. After a self-selected warm up, an isokinetic dynamometer was used to assess the peak concentric torque production of the hamstrings and quadriceps. The protocol included 5 repetitions at 60°/s to measure strength, 20 repetitions at 180°/s to measure endurance, and 15 repetitions at 300°/s to measure speed-strength. Injury incidence data were provided from the sports medicine team after 3 months and during the indoor season. Qualitative differences in HQR values at all speeds were compared between athletes who sustained thigh muscle injuries and uninjured peers matched by sex, height, mass, and event. RESULTS: Mean HQR data are presented in Table 1. Five athletes (2 females) sustained injuries involving the hamstrings or quadriceps. On average, the uninjured matched pairs had greater HQR, except at 300°/s of the left leg. CONCLUSION: During this initial phase of a continuing longitudinal study, it appears that HQR may be considered when assessing thigh muscle injury risk. Further research is needed to validate these findings and explore the potential integration of HQR assessments into comprehensive injury prevention strategies for athletes
Complementary Sensory and Associative Microcircuitry in Primary Olfactory Cortex
The three-layered primary olfactory (piriform) cortex is the largest component of the olfactory cortex. Sensory and intracortical inputs converge on principal cells in the anterior piriform cortex (aPC).Wecharacterize organization principles of the sensory and intracortical microcircuitry of layer II and III principal cells in acute slices of rat aPC using laser-scanning photostimulation and fast two-photon population Ca²⁺ imaging. Layer II and III principal cells are set up on a superficial-to-deep vertical axis. We found that the position on this axis correlates with input resistance and bursting behavior. These parameters scale with distinct patterns of incorporation into sensory and associative microcircuits, resulting in a converse gradient of sensory and intracortical inputs. In layer II, sensory circuits dominate superficial cells, whereas incorporation in intracortical circuits increases with depth. Layer III pyramidal cells receive more intracortical inputs than layer II pyramidal cells, but with an asymmetric dorsal offset. This microcircuit organization results in a diverse hybrid feedforward/recurrent network of neurons integrating varying ratios of intracortical and sensory input depending on a cell’s position on the superficial-to-deep vertical axis. Since burstiness of spiking correlates with both the cell’s location on this axis and its incorporation in intracortical microcircuitry, the neuronal output mode may encode a given cell’s involvement in sensory versus associative processing
Pacemaker implantation in small hospitals: complication rates comparable to larger centres
Some countries have a demography that makes it necessary to maintain relatively small pacemaker centres. We wanted to assess the quality of pacemaker surgery in two such hospitals. Through patient records we gathered information on ∼535 consecutive primary pacemaker implantations in two small pacemaker centres with 30 and 80 annual operations, respectively. All patients were followed for 3 years. All complications documented in the patient records were registered. Furthermore, we performed a non-systematic literature search comparing our data with reports from major centres published over the last 10 years.We found 72 complications in 64 (12.0%) of the patients, the most common being bleeding, lead failure, and pneumothorax. If minor bleedings without any consequences for the patients are excluded, the number of complications was 46 in 40 patients (7.5%). We had to reoperate on 5.2% of the patients. There was no statistically significant difference in complication rates between the two hospitals. Education candidates generated statistically significant more complications than experienced doctors (13.7 vs. 7.1%, P < 0.05). There are no generally accepted norms of complication rates in pacemaker surgery. However, we found no indications that our centres have a rate of complications that is unacceptably high
Measurement of heavy-hole spin dephasing in (InGa)As quantum dots
We measure the spin dephasing of holes localized in self-assembled (InGa)As
quantum dots by spin noise spectroscopy. The localized holes show a distinct
hyperfine interaction with the nuclear spin bath despite the p-type symmetry of
the valence band states. The experiments reveal a short spin relaxation time
{\tau}_{fast}^{hh} of 27 ns and a second, long spin relaxation time
{\tau}_{slow}^{hh} which exceeds the latter by more than one order of
magnitude. The two times are attributed to heavy hole spins aligned
perpendicular and parallel to the stochastic nuclear magnetic field. Intensity
dependent measurements and numerical simulations reveal that the long
relaxation time is still obscured by light absorption, despite low laser
intensity and large detuning. Off-resonant light absorption causes a
suppression of the spin noise signal due to the creation of a second hole
entailing a vanishing hole spin polarization.Comment: accepted to be published in AP
Monongalia area survey, 1981 : citizens\u27 views on industrial development and quality of life
Accumulation of formamide in hydrothermal pores to form prebiotic nucleobases
Formamide is one of the important compounds from which prebiotic molecules can be synthesized, provided that its concentration is sufficiently high. For nucleotides and short DNA strands, it has been shown that a high degree of accumulation in hydrothermal pores occurs, so that temperature gradients might play a role in the origin of life [Baaske P, et al. (2007) Proc Natl Acad Sci USA 104(22):9346−9351]. We show that the same combination of thermophoresis and convection in hydrothermal pores leads to accumulation of formamide up to concentrations where nucleobases are formed. The thermophoretic properties of aqueous formamide solutions are studied by means of Infrared Thermal Diffusion Forced Rayleigh Scattering. These data are used in numerical finite element calculations in hydrothermal pores for various initial concentrations, ambient temperatures, and pore sizes. The high degree of formamide accumulation is due to an unusual temperature and concentration dependence of the thermophoretic behavior of formamide. The accumulation fold in part of the pores increases strongly with increasing aspect ratio of the pores, and saturates to highly concentrated aqueous formamide solutions of ∼85 wt% at large aspect ratios. Time-dependent studies show that these high concentrations are reached after 45–90 d, starting with an initial formamide weight fraction of 10−3 wt % that is typical for concentrations in shallow lakes on early Earth
Impact of laminar flow velocity of different acids on enamel calcium loss
Objective: The aim of the study was to evaluate the impact of flow velocity under laminar flow conditions of different acidic solutions on enamel erosion. Material and methods: A total of 240 bovine enamel specimens were prepared and allocated to 30 groups (n = 8 each). Samples of 18 groups were superfused in a flow chamber system with laminar flow behavior using 1ml of citric acid or hydrochloric acid (HCl) of pH 2.0, 2.6 or 3.0. Flow rates in the sample chamber were adjusted to 10, 60 or 100μl/min. To simulate turbulent flow behavior, samples of six groups were immersed in 1ml of the respective solution, which was vortexed (15min, 600rpm). For simulating non-agitated conditions, specimens of the remaining six groups were immersed in 1ml of the respective solution without stirring. Calcium in the solutions, released from the enamel samples, was determined using Arsenazo III method. Results: For acidic solutions of pH 2.6 and 3.0, erosive potential of citric acid was equivalent to that of HCl at a flow of 100μl/min. The same observation was made for the samples subjected to turbulent conditions at pH 3. At all other conditions, citric acid induced a significantly higher calcium loss than HCl. Conclusion: It is concluded that under slow laminar flow conditions, flow rate variations lead to higher erosive impact of citric acid compared to hydrochloric acid at pH 2.0, but not at pH ≥ 2.6 and increasing laminar flow or turbulent conditions. Clinical relevance: Erosive enamel dissolution under laminar flow conditions is a complex issue influenced by flow rate and acidic substrat
Use of soil moisture information in yield models
There are no author-identified significant results in this report
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