Survey of man-made electrical noise affecting radio broadcasting

Survey, consisting of limited noise measurements, was made to augment and verify existing data at HF and VHF and to obtain basic data at UHF. Exact frequencies were determined by the absence of intentionally generated signals around three selected frequencies

Superior sperm competitors sire higher-quality young

The evolution of polyandry remains controversial. This is because, unlike males, in many cases multiple mating by females does not increase fecundity and inevitably involves some costs. As a result, a large number of indirect benefit models have been proposed to explain polyandry. One of these, the good sperm hypothesis, posits that high-quality males are better sperm competitors and sire higher-quality offspring. Hence, by mating multiply, females produce offspring of superior quality. Despite being potentially widely applicable across species, this idea has received little attention. In a laboratory experiment with yellow dung flies ( Scathophaga stercoraria ) we found that males that were more successful in sperm competition also had offspring that developed faster. There was no relationship between paternal success in sperm competition and the ability of offspring to survive post-emergence starvation. Since faster development times are likely to be advantageous in this species, our data provide some support for polyandry evolving as a means of producing higher-quality offspring via sperm competition

Lactate Threshold: Land versus Water Treadmill Running

Aquatic treadmill running has become increasingly popular for rehabilitation and training purposes due to decreased joint impact on the lower extremities, which is beneficial for special populations such as the injured, elderly, arthritic, and obese (Greene et al., 2009; Hall, Grant, Blake, Taylor, & Garbutt, 2004). Accordingly, researchers have compared key differences such as heart rate (HR), oxygen consumption (VO2), respiratory exchange ratio (RER), stride frequency, and rating of perceived exertion (RPE) between land and water running at maximal and submaximal efforts (Brubaker, Ozemek, Gonzalez, Wiley, & Collins, 2011; Rife, Myrer, Feland, Hunter, & Fellingham, 2010; Rutledge, Silvers, Browder, & Dolny, 2007; Silvers, Rutledge, & Dolny, 2007). As the benefits of aquatic treadmill running continue to be unveiled, there is an interest for healthy individuals to use the system to supplement training while limiting joint stress. Rutledge et al. (2007) revealed VO2 values at 6.5, 7.5 and 8.5 mph on an aquatic treadmill with no jet resistance to be 33.97 ± 4.0, 37.96 ± 4.0, and 43.6 ± 4.0 mL•kg-1•min-1, respectively. Watson et al. (2012) also revealed VO2 values on an aquatic treadmill at 4.5, 6.0, and 7.5 mph with no jet resistance to be 20.58 ± 3.36, 29.27 ± 3.89, and 35.77 ± 4.02 mL•kg-1•min-1, respectively. These articles demonstrate the linear relationship that exists with increasing workloads with concomitant increases in VO2 with aquatic treadmill running. As metabolic demands increase, a reliance on anaerobic metabolism ensues and the work rate at which lactate begins to accumulate in the blood is called the lactate threshold (LT) (Stainsby & Brooks, 1990). The importance of determining LT is supported by a large body of evidence to predict aerobic endurance capacity (Faude, Kindermann, & Meyer, 2009). As such, researchers have employed great efforts to predict LT via field tests to determine the correct training intensity for endurance athletes (McGehee, Tanner, & Houmard, 2005). An early study of LT revealed a strong relationship (r ≥ .91) between treadmill velocity at the onset of plasma lactate accumulation and running performance at distances ranging from 3.2 km to 42 km (Farrell, Wilmore, Coyle, Billing, and Costill, 1979). In other words, a faster sustainable work rate prior to a lactate accumulation or threshold will increase performance. Comparisons for lactate concentrations during deep water and land treadmill running have been examined previously. Frangolias and Rhodes (1996) reviewed that during submaximal intensities of deep water versus land running, at the same relative VO2 water exercise resulted in a lower HR with higher blood lactate, RER, and RPE. These same authors previously reported that at maximal efforts on land versus deep water running, there was no statistical difference between lactate concentrations 30 s and 5 min post-exercise (Frangolias & Rhodes, 1995). However, not all water immersion running studies support similar peak lactate values (Frangolias & Rhodes, 1996; Svedenhag & Seger, 1992). In a shallow water pool, a study by Town and Bradley (1991) revealed no statistical differences between land and water running for peak lactate values. However, lactate concentration in the water was 80% of that from land exercise. The authors stated that the “push-off” phase, which enabled ground contact, elicited similar running technique to land treadmills and could be partially responsible for similar physiological responses to land. In recent years the availability of aquatic treadmills allows for a more favorable comparison of land and water running due to the implication of the “push-off” phase as discussed by Town and Bradley. Silvers et al. (2007) revealed no statistical difference between peak lactate concentrations in VO2peak tests run on land versus aquatic treadmills. Zobell (2009) examined a comparison of LT between land and aquatic treadmill running which showed higher lactate levels in the water compared to land. However, no clear answers have developed as to a comparison of the LT on land vs. aquatic treadmill running. Therefore, the purpose of this study was to determine the LT while running on a land and an aquatic treadmill and compare to see if the intensities are equivalent

Virtual Social Movements

http://deepblue.lib.umich.edu/bitstream/2027.42/51343/1/579.pd

Acute Effects of Contractile Activity on Skeletal Muscle Exosomes

Introduction: Skeletal muscle functions as an endocrine organ, and a key way to accomplish that is through exosomes. The internal budding of a multivesicular body (MVB) forms exosomes and contains mRNA, miRNA, and proteins. Through a multifaceted approach, the following three experiments were designed to better understand the effect of contractile activity on skeletal muscle MVB/exosome biogenesis and release. Study 1: Exosome-related pathway response to acute exercise. Sedentary, lean, healthy male subjects (n=12) performed 45 min cycling (AEx), followed by single leg knee extensor exercise (A+REx). A biopsy was obtained prior to exercise and 1 hr post-exercise from each leg. Stimulation of MVB biogenesis occurred in the A+REx group, with miRNA biogenesis activated by both AEx and A+REx. Overall, there appeared to be no additive effect of REx for angiogenesis or mitochondrial improvements following acute exercise. Our data displays no total protein changes for known exosome surface markers. Increased MVB biogenesis and release indicate exciting possibilities for exercise stimulated exosome release. Study 2: Effects of obesity and acute resistance exercise on skeletal muscle intercellular communication pathways. To more fully determine the effect of resistance exercise (REx) alone on MVB/exosome signaling and obesity on skeletal muscle angiogenesis, the following study was performed: Lean (LN) and obese (OB) (n=8 each group) sedentary human subjects performed single leg knee extension exercise at 80% 1RM, 3 sets, 8-12 reps. Muscle biopsies were obtained at rest, 15 min, and 3 hr post-exercise. With OB, baseline anti-angiogenic miRNA and diminished MVB biogenesis were displayed, along with an increased anti-angiogenic factor thrombospondin-1 in response to acute REx, indicating plausible pathways to explain diminished capillary density of Type II muscle fibers. No total changes were observed in VEGF between LN and OB, though a trend for reduced VEGF existed in the OB group compared to LN. Study 3: Role of CaMKII in skeletal muscle exosome release. To determine a candidate pathway linked with calcium signaling, muscle contraction, and exosome release, specific attention was given to the role of calcium-calmodulin kinase II (CaMKII). Skeletal muscle biopsies were obtained from lean, healthy, male college-aged subjects (n=8) and satellite cells isolated for use in cell culture (SkMCC). To ensure proper differentiation, SkMCC had markers Pax7, Myogenin (MyoG), and myosin heavy chain (MHC) measured via Western blot on days 0, 2, 4, 6, and 8. SkMCC were stimulated for 30 min with electrical pulse stimulation (EPS), an exercise mimetic, to validate activation of in vivo exercise pathways adenosine monophosphate kinase (AMPK), mitogen activated protein kinase (MAPK) and CaMKII. SkMCC underwent 24 h of EPS with and without the addition of KN-93, a chemical inhibitor of CaMKII. Quantification of isolated exosomes following EPS was accomplished by use of a NanoSight, RT-PCR, and Western blot analysis. The main finding, despite an identifiable change in MHC and formation of myotubes, minimized contractile activity in vitro leading to inadequate activation of metabolic pathways and MVB release. Strong trends for the phosphorylation of AMPK, interaction of CaMKII with clathrin gene expression, reduced gene expression of PDK4, and reduced total nanoparticles in response to EPS indicate that changes occurred, though not to the anticipated levels based on preliminary data

Mapping the Surgical Landscape: Resonances and Divergences Between Theories of Cosmetic and Transsexual Body Modification

This paper explores the limitations of the disciplinary divide between feminist studies of cosmetic surgery and trans studies of sex reassignment surgery, in order to unpack assumptions that may otherwise go unchallenged within each field. We focus on themes of conformity and transgression, and borders and identity. Résumé Cet article explore les limites de la division entre les études des femmes sur la chirurgie cosmétique et les études sur les trans sur les chirurgie de réassignation de sexe, afin de déballer les assomption qui ne serait autrement pas mises au défi chacune dans leur domaine. Nous nous concentrons sur les thèmes de conformité et de transgression, et des frontières et de l'identité