Mechanically fastened joints in woven fabric composites

Strength analysis for composite bolted joints involves the mating of a stress analysis with an appropriate mode specific failure criterion for each of the primary failure modes. The stress analysis and failure criteria are independent of each other and can be manipulated separately in order to optimize the strength analysis package formed by their coupling. Material properties tests were conducted on rubber toughened graphite-epoxy material to measure the basic strength and stiffness in the warp and fill directions and in shear. Test matrices are summarized for investigations of laminate configuration, stacking sequence, fastener diameter, edge distance, fastener half spacing, laminate thickness, and fastener torque. A three dimensional finite element analysis computer program was written and failure criteria for net tension, shearout, and bearing were determined

Basic Measurements of Division 1 Collegiate Baseball Pitchers to Predict Grip Strength and Spin Rate

Basic measurements such as range of motion (ROM), grip strength (GS), height, and arm length have been associated with the rate that the ball spins. Increased spin rate along with the axis of rotation of a baseball is linked to the movement that a pitch experiences during its delivery. This spin rate gives a batter difficulty when trying to contact the ball. Plainly, the more spin the more likely the chance the batter will miss. PURPOSE: The purpose of this study was to use external range of motion (EROM), GS, height, weight, forearm length, and forearm circumference to predict spin rate. METHODS: Thirteen right-handed division 1 collegiate baseball pitchers (height 183.2cm± 6.9cm, weight 90kg ± 12kg, forearm length 27.5cm ± 1.3cm, forearm circumference 29.8cm ± 2.1cm, EROM 111.3° ± 9.0°, GS 57.3kg ± 8.4kg, spin rate 2057.2rpm ±160.5rpm) were recruited for this study. Height and weight measurements were recorded using a Doran physician\u27s scale. Measurements of the right forearm were taken from the medial epicondyle of the humerus to the styloid process of the ulna. Forearm circumference was taken from the thickest portion of the forearm. External rotation was measured using a goniometer from a lying position. Spin rate was calculated using a Yakkertech which uses visual imaging technology to calculate spin rate and eliminates the gyro spin of the ball. Ipsilateral hand grip strength was assessed using a Delsys handgrip dynamometer at 90-degree elbow flexion with the elbow unsupported and hand in a neutral grip. The participant was given three attempts to exert as much force as possible and the maximum force in kg was recorded. External rotation of the glenohumeral joint was measured using a goniometer from a lying position with the humerus abducted 90 degrees the subjects were instructed to start with their forearm in a vertical position then slowly drop the back of their hand toward the table. RESULTS: Data were assessed using a forward stepwise multiple regression to identify a statistically significant (p\u3c 0.05) prediction model of spin rate using basic measurements described above. Forearm length was the only variable that was a statistically significant predictor and accounted for 41.8% of the variance in predicting spin rate. The resulting prediction equation was as follows: Spin rate= -165.655rpm - (80.945x FL; R2.418; SEE=127.8). CONCLUSION: Increased forearm length allows for the moment arm to produce more torque on the ball thus increasing the spin rate allowing increased movement on the ball

Cortical Activity Measured with Low-Intensity Fatiguing Contractions of the Quadriceps Muscle Group

Modulation of force production required during exercise is regulated from various mechanisms in the central and peripheral nervous system. Fatigue is influenced by various mechanics that may hinder the ability to continuously sustain force production. The neural activation patterns of these systems can be recorded as electrical impulses using several non-invasive techniques. The ability to examine these during fatiguing exercise has provided further insight into activation patterns in the central nervous system (i.e., motor and pre-motor cortex) during sustained muscle contractions. Electroencephalography (EEG) has been recently utilized to examine changes associated with central fatigue, but limited advancements in technology for neuromuscular fatigue has inhibited progression in this area of research. PURPOSE:The purpose of this study is to discover the effects of low-intensity muscular fatigue on central mechanisms. METHODS:Following 3 Maximal Voluntary Contractions (MVCs), four lower-body resistance trained males (23yrs.±2, ht.176cm ±6., wt. 89kg ±16.) performed 60 second submaximal (30% MVC) isometric ramp contraction of the knee extension exercise. Knee extensions were performed on a custom-built seat using an S-beam load-cell to measure isometric force production of the quadriceps muscle group. During the fatiguing contractions, participants were encouraged to perform as many trapezoidal ramp contractions (i.e., 30%) as possible, until they could no longer sustain the required force production. Fatigue was established when the participant could no longer maintain the contraction force within 10% for no less than 3 seconds during the isometric hold.Cortical activity was recorded with a 24-electrode electroencephalogram (EEG) soft cap. Once EEG signals were referenced, bandpass filtered, and cleaned, gamma and beta frequency band data and topographic maps were computed for electrodes over the cerebral cortex (C3, Cz, and C4). Two separate repeated measures ANOVAs were used to compare the band’s during the first 3 seconds of the force plateau of the pre and post contractions.RESULTS:There were no significant differences over time in any of the electrodes/bands (p\u3e .05). DISCUSSION:These data indicate that low-intensity muscular fatigue is not mediated by central mechanisms in the C3, C4, Cz electrode spaces in the higher frequency bands (beta and gamma). Future research will examine other central mechanisms that underlie the neural circuit involved in muscular fatigue

Spatial Distribution of Earthworms in an East Texas Forest Ecosystem

Earthworms were collected and identified in different ecological habitats of the Stephen F. Austin Experimental Forest (SFAEF) in the Piney Woods Ecoregion (PWE) of Texas. Earthworm spatial distribution data were collected over four distinct ecological habitats with a range of soil conditions and vegetative cover. A total of 128 sampling plots were surveyed in two different, broadly defined locations (mesic slope = 68 plots, dry-mesic upland = 60 plots). Using multivariate classification/ordination (TWINSPAN) and detrended correspondence analysis (DCA) of overstory vegetation data, these two locations were further divided into four distinct habitats: dry-mesic mixed upland, transitional zone, mesic slope and wet forested seeps. By using TWINSPAN and principal component analysis (PCA), it was found that earthworm species assemblages and understory vegetation corresponded to these discrete ecological habitats. ArcGIS10 was then used to create spatial distribution maps of earthworm species throughout these delineated ecological habitats in the SFAEF. Six earthworm species from the native North American genus Diplocardia were collected at SFAEF: D. caroliniana Eisen (1899), D. eiseni Michaelsen (1894), D. komareki Gates (1977); D. macdowelli Murchie (1963), D. mississippiensis Smith (1924) and D. ornata Gates (1943). Two earthworm species from the native North American genus Bimastos were collected: B. heimburgeri Smith 1928 and B. longicinctus Smith and Gittins 1915. The collection of B. longicinctus is a new state record for Texas. Amynthas corticis Kinberg (1867) specimens were collected, which represent a non-native genus from Southeast Asia. Ocnerodrilidae, a megadrile family first described by Beddard in 1891, were also collected likely representing non-native species originating from intertropical America and Africa (Christoffersen, 2008)

Somatotyping of Division I Athletes

Somatotyping has previously examined athletes\u27 genetic morphology. Categorization of somatotyping can be utilized in athletes for specialized, adaptive sports performance. PURPOSE: The purpose of this study was to report somatotyping differences (ectomorph, mesomorph, and endomorph) in selected Division I athletes. METHOD: 39 male football athletes and seven female softball Division I athletes were recruited for this investigation. Height (m), weight (kg), waist-to-hip ratio (cm), and a 4-site skinfold measurement was collected. Skinfold locations were recorded from the triceps (mm), subscapular (mm), supraspinal (mm), and the medial calf (mm). Biepicondylar breadth measures of the humerus (cm), and the femur (cm) were recorded at a respective 90°. Additionally, the girth of the subject’s dominant upper arm (cm) and dominant calf (cm) were recorded. All measurement locations were taken from the Heath-Carter Anthropometric protocol, respectfully. The Heath Carter Somatotype Worksheet consists of a rating scale that is based on a 3-component categorization. All measures are considered when calculating a participant\u27s score. Scores between .5 and 2.5 are low, 3 to 5 are moderate, 5.5 to 7 are high and anything over a 7.5 is considered very high. The first component calculated scores of endomorphy, the second calculated mesomorphy scores, and the last component calculated ectomorph scores. Using these measurements, equations are used to determine a participant’s score to a specific somatotype. The athletes\u27 numbers were then processed and plotted on a 2-D graph plotting the somatotype (X= ectomorph-endomorph, Y=2 x mesomorphy- (endomorphy+ectomorph)). RESULTS: There was a clear indication that somatotyping had variety based on sports and position specialization in football athletes. Football athletes consisted of 6 endomorphs, 30 mesomorphs, and 3 ectomorphs, while softball athletes consisted of 7 meso-endomorphs. CONCLUSION: Due to the anthropometric position differences in male football athletes there was a considerable amount of variety and lack of specificity, while the female softball athletes consisted of a lesser variety in anthropometric measures

Conflict, Crisis, and Abuse in Dharavi, Mumbai: Experiences from Six Years at a Centre for Vulnerable Women and Children

Nayreen Daruwalla and colleagues describe the Centre for Vulnerable Women and Children, which serves clients coping with crisis and violence in the urban setting of Dharavi, Mumbai

Regional and scale-specific effects of land use on amphibian diversity [poster]

Background/Question/Methods Habitat loss and degradation influence amphibian distributions and are important drivers of population declines. Our previous research demonstrated that road disturbance, development and wetland area consistently influence amphibian richness across regions of the U.S. Here, we examined the relative importance of these factors in different regions and at multiple spatial scales. Understanding the scales at which habitat disturbance may be affecting amphibian distributions is important for conservation planning. Specifically, we asked: 1) Over what spatial scales do distinct landscape features affect amphibian richness? and 2) Do road types (non-rural and rural) have similar effects on amphibian richness? This is the second year of a collaborative, nationwide project involving 11 U.S. colleges integrated within undergraduate biology curricula. We summarized North American Amphibian Monitoring Program data in 13 Eastern and Central U.S states and used geographic information systems to extract landscape data for 471 survey locations. We developed models to quantify the influence of landscape variables on amphibian species richness and site occupancy across five concentric buffers ranging from 300m to 10,000m. Results/Conclusions Across spatial scales, development, road density and agriculture were the best predictors of amphibian richness and site occupancy by individual species. Across regions, we found that scale did not exert a large influence on how landscape features influenced amphibian richness as effects were largely comparable across buffers. However, development and percent impervious surface had stronger influence on richness at smaller spatial scales. Richness was lower at survey locations with higher densities of non-rural and rural roads, and non-rural road density had a larger negative effect at smaller scales. Within regions, landscape features driving patterns of species richness varied. The scales at which these factors were associated with richness were highly variable within regions, suggesting the scale effects may be region specific. Our project demonstrates that networks of undergraduate students can collaborate to compile and analyze large ecological data sets, while engaging students in authentic and inquiry-based learning in landscape-scale ecology

RNA-binding properties and membrane insertion of Melon necrotic spot virus (MNSV) double gene block movement proteins

Advances in structural and biochemical properties of carmovirus movement proteins (MPs) have only been obtained in p7 and p9 from Carnation mottle virus (CarMV). Alignment of carmovirus MPs revealed a low conservation of amino acid identity but interestingly, similarity was elevated in regions associated with the functional secondary structure elements reported for CarMV which were conserved in all studied proteins. Nevertheless, some differential features in relation with CarMV MPs were identified in those from Melon necrotic virus (MNSV) (p7A and p7B). p7A was a soluble non-sequence specific RNA-binding protein, but unlike CarMV p7, its central region alone could not account for the RNA-binding properties of the entire protein. In fact, a 22-amino acid synthetic peptide whose sequence corresponds to this central region rendered an apparent dissociation constant (K(d)) significantly higher than that of the corresponding entire protein (9 mM vs. 0.83-25.7 microM). This p7A-derived peptide could be induced to fold into an alpha-helical structure as demonstrated for other carmovirus p7-like proteins. Additionally, in vitro fractionation of p7B transcription/translation mixtures in the presence of ER-derived microsomal membranes strongly suggested that p7B is an integral membrane protein. Both characteristics of these two small MPs forming the double gene block (DGB) of MNSV are discussed in the context of the intra- and intercellular movement of carmovirus