Sex Differences in Power Output at Maximal Load during the Barbell Squat

When maximal muscular power outputs are examined relatively, sex differences appear to be non-existent. In terms of absolute power, however, significant differences persist between sexes. In both cases, the majority of metrics are obtained at optimal loads for power outputs. However, little is known in regards to differences in power outputs at maximal strength capacity of men and women. PURPOSE: The current investigation aimed to identify sex differences of concentric (C) and eccentric (E) power measures at maximal load during the barbell back squat (SQ). METHODS: A total of 8 participants (4 men and 4 women) completed one experimental exercise session testing SQ 1-Repetition maximum (1RM) following the National Strength and Conditioning Association 1RM protocol. A Bar Sensei (accelerometer) was attached to the barbell during the 1RM test, and used to collect C and E Average Power (AP), Peak Power (PP), Average Force (AF), Peak Force (PF), Average Speed (AS), Peak Speed (PS), as well as C POP-100, Distance of Movement (DM), and Mass Lifted (ML). RESULTS: An independent-sample t test identified statistically different C PF (p=0.04), C AF (p=0.03), ML (p=0.03), E PF (p=0.03), E AF (p=0.03), E PP (p=0.03) and E AP (p=0.047) between men (C PF 2054.1±825.7 N; C AF 1685.4±630.4 N; ML 367.5±133 lbs.; E PF 1821.7±633 N; E AF 1646.3±597.9 N; E PP 762.4±248.4 W; and E AP 428.5±130.4 W) and women (C PF 940.2±178.3 N; C AF 792.7±143.1 N; ML 178.8±33.5 lbs.; E PF 896.5±138.9 N; E AF 803.5±146.7 N; E PP 361.15±137 W; and E AP 230.6±90.7 W). Contrariwise, no significant differences were indicated for C POP-100 (p=0.39), C PS (p=0.95), C AS (p=0.70), C PP (p=0.13), C AP (p=0.19), DM (p=0.46), E PS (p=0.66), and E AS (p=0.93) of men (C POP-100 .21±.15 m/s; C PS .80±.15 m/s; C AS .44±.29 m/s; C PP 1471.7±727.8 W; C AP 824.9±698.3 W; DM .42±.23 m; E PS .52±.24 m/s; and E AS .29±.11 m/s) and women (C POP-100 .14±.04 m/s; C PS .82±.44 m/s; C AS .36±.23 m/s; C PP 727.8±446 W; C AP 292.6±196.7 W; DM .31±.15 m; E PS .45±.15 m/s; and E AS .30±.10 m/s). CONCLUSION: These results provide further explanation of sex-differences in power production. The difference in C PF, C AF, ML, E PF, E AF, and E PP complement results of pervious sex-differentiating reports. However, men and women produce C POP-100, C PS, C AS, C PP, C AP, DM, E PS, and E AS at equivalent load percentage provides novelty to the current literature. Further research is needed to explain reasoning of male and female power differences and similarities, and to determine sex-specific training implication for improvement in power performance

The Late Cenozoic tectonic evolution of Gurla Mandhata, Southwest Tibet

How strain within the Tibetan plateau is geodynamically linked to that within the Himalayan thrust belt is a topic receiving considerable attention. The right-lateral Karakoram fault plays key roles in models describing the structural relationship between southern Tibet and the Himalaya. Considerable debate exists at the southeastern end of the Karakoram fault, where the role of the Karakoram fault is interpreted in two very different ways. One interpretation states that slip along the Karakoram fault extends eastward along the Indus-Yalu suture zone, thereby bypassing the Himalayan thrust belt to its north. The other, interprets that a significant component of the slip is fed southward into the Himalayan thrust belt along the Gurla Mandhata detachment. To evaluate this debate, the late Miocene fault slip rate history of the Gurla Mandhata detachment system is reconstructed from thermokinematic modeling with Pecube of zircon (U-Th)/He and biotite and muscovite 40Ar/39Ar thermochronometric ages. This slip rate history is then compared to that of the Karakoram fault. Zircon (U-Th)/He thermochronometric data from 3 east-west footwall transects reveal cooling of the Gurla Mandhata footwall through the zircon partial retention zone, from 8.01±1.31 Ma to 2.56±0.7 Ma. Results from ~21,100 Pecube models show a southward progression of decreasing fault slip magnitude and rate along the Gurla Mandhata detachment system. The northern transect modeling results show an initiation age from 14-11 Ma with a mean fault slip rate of 5.0±0.9 mm/yr. The central transect modeling results show an initiation age from 14-11 Ma with a mean fault slip rate of 3.3±0.6 mm/yr. The southern transect modeling results show an initiation age from 15-8 Ma with a mean fault slip rate of 3.2±1.6 Ma. These fault initiation ages and fault slip rate results match estimates obtained for the Karakoram fault across several timescales, supporting the idea that the two are kinematically linked. Specifically, the data are consistent with the Gurla Mandhata detachment acting as a right-step extensional stepover along which the Karakoram fault slip is transferred into the Himalayan thrust belt of western Nepal

Site-specific management of pH-induced iron chlorosis of maize

A study was conducted over nine site/years in Nebraska, USA between 2004 and 2005 to evaluate the potential to predict chlorosis-prone areas within fields which are relatively stable in space and time. The study also investigated the potential benefits of site-specific cultivar management according to chlorosis pressure. Sites were mapped for soil apparent electrical conductivity (ECa) at two depths (0-30 cm and 0-90 cm), and soil pH at a depth of 10 cm. Sites were also sampled by hand on a regular grid to a depth of 20 cm and analyzed for a range of soil properties. Sites were evaluated in-season with natural color and near-infrared imagery, and at the end of the season by yield mapping. In all or a portion of each field, replicated paired strips of two maize cultivars were planted, one considered susceptible to iron chlorosis (P34N42), another with similar characteristics but tolerant to iron chlorosis (P34B99). Detailed evaluation of the ability to predict iron chlorosisprone areas was conducted over 3 site/years. Management zones were delineated using combinations of yield data, biCa and vegetation indices derived from aerial imagery. Across all locations, grid sampled pH ranged from 6.1 to 9.1; on-the-go pH ranged from 4.9 to 9.2; shallow ECa ranged from 0.1 to 39 InSini: deep ECa ranged From 0.2 to 152 mS/rn. For one field, planted to maize one year and soybean the next, two chlorosis management zones were consistently delineated both years, with similar spatial relationships. For another field, soil water holding capacity was a larger yield limiting factor than iron chlorosis and management zones for iron chlorosis could riot be delineated. For 8 site/years where paired strips of chlorosis-prone or tolerant cultivars were planted, no distinct advantage of site-specific maize cultivar management was found based on yield response of the two cultivars evaluated. Generally P34B99 yields were superior to P34N42 regardless of the level of chlorosis pressure. This study found spatial information on factors conducive to iron chlorosis can be useful in delineating chlorosis-prone areas within fields_ However, other yield limiting [-actors may confound delineation of zones strictly for chlorosis management. Successful spatial cultivar selection for iron chlorosis management will require the use of cultivars with response characteristics which differ more than those used in this study

Miocene initiation and acceleration of extension in the South Lunggar rift, western Tibet: Evolution of an active detachment system from structural mapping and (U-Th)/He thermochronology

This is the publisher's version, also available electronically from http://onlinelibrary.wiley.com/doi/10.1002/tect.20053/abstractOngoing extension in Tibet may have begun in the middle to late Miocene, but there are few robust estimates of the rates, timing, or magnitude of Neogene deformation within the Tibetan plateau. We present a comprehensive study of the seismically active South Lunggar rift in southwestern Tibet incorporating mapping, U-Pb geochronology and zircon (U-Th)/He thermochronology. The South Lunggar rift is the southern continuation of the North Lunggar rift and comprises a ~50 km N-S central horst bound by two major normal faults, the west-dipping South Lunggar detachment and the east-dipping Palung Co fault. The SLD dips at the rangefront ~20°W and exhumes a well-developed mylonite zone in its footwall displaying fabrics indicative of normal-sense shear. The range is composed of felsic orthogneiss, mafic amphibolite, and leucogranite intrusions dated at ~16 and 63 Ma. Zircon (U-Th)/He cooling ages are Oligocene through late Pliocene, with the youngest ages observed in the footwall of the SLD. We tested ~25,000 unique thermokinematic forward models in Pecube against the structural and (U-Th)/He data to fully bracket the allowable ranges in fault initiations, accelerations, and slip rates. We find that normal faulting in the SLR began in the middle Miocene with horizontal extension rates of ~1 mm a−1, and in the north accelerated at 8 Ma to 2.5–3.0 mm a−1 as faulting commenced on the SLD. Cumulative horizontal extension across the SLR ranges from <10 km in the south to 19–21 km in the north

Phi-values in protein folding kinetics have energetic and structural components

Phi-values are experimental measures of how the kinetics of protein folding is changed by single-site mutations. Phi-values measure energetic quantities, but are often interpreted in terms of the structures of the transition state ensemble. Here we describe a simple analytical model of the folding kinetics in terms of the formation of protein substructures. The model shows that Phi-values have both structural and energetic components. In addition, it provides a natural and general interpretation of "nonclassical" Phi-values (i.e., less than zero, or greater than one). The model reproduces the Phi-values for 20 single-residue mutations in the alpha-helix of the protein CI2, including several nonclassical Phi-values, in good agreement with experiments.Comment: 15 pages, 3 figures, 1 tabl

Delinearing site-specific management zones for pH-induced iron chlorosis

Iron chlorosis can limit crop yield, especially on calcareous soil. Typical management for iron chlorosis includes the use of iron fertilizers or chlorosis tolerant cultivars. Calcareous and non-calcareous soil can be interspersed within fields. If chlorosis-prone areas within fields can be predicted accurately, site-specific use of iron fertilizers and chlorosis-tolerant cultivars might be more profitable than uniform management. In this study, the use of vegetation indices (VI) derived from aerial imagery, on-the-go measurement of soil pH and apparent soil electrical conductivity (ECa) were evaluated for their potential to delineate chlorosis management zones. The study was conducted at six sites in 2004 and 2005. There was a significant statistical relationship between grain yield and selected properties at two sites (sites 1 (2005) and 3), moderate relationships at sites 2 and 4, and weak relationships at site 5. For sites 1 (2005) and 3, and generally across all sites, yield was predicted best with the combination of NDVI and deep ECa. These two properties were used to delineate chlorosis management zones for all sites. Sites 1 and 3 showed a good relationship between delineated zones and the selected properties, and would be good candidates for site-specific chlorosis management. For site 5, differences in the properties between mapped zones were small, and the zones had weak relationships to yield. This site would be a poor candidate for site-specific chlorosis management. Based on this study, the delineation of chlorosis management zones from aerial imagery combined with soil ECa appears to be a useful tool for the site-specific management of iron chlorosis

The future of social is personal: the potential of the personal data store

This chapter argues that technical architectures that facilitate the longitudinal, decentralised and individual-centric personal collection and curation of data will be an important, but partial, response to the pressing problem of the autonomy of the data subject, and the asymmetry of power between the subject and large scale service providers/data consumers. Towards framing the scope and role of such Personal Data Stores (PDSes), the legalistic notion of personal data is examined, and it is argued that a more inclusive, intuitive notion expresses more accurately what individuals require in order to preserve their autonomy in a data-driven world of large aggregators. Six challenges towards realising the PDS vision are set out: the requirement to store data for long periods; the difficulties of managing data for individuals; the need to reconsider the regulatory basis for third-party access to data; the need to comply with international data handling standards; the need to integrate privacy-enhancing technologies; and the need to future-proof data gathering against the evolution of social norms. The open experimental PDS platform INDX is introduced and described, as a means of beginning to address at least some of these six challenges

Soil genesis and development, lesson 4: Soil profile development

The processes occurring over time in a soil are reflected in vertical and lateral physical and chemical characteristics of that soil. The four soil forming processes, in conjunction with the five factors of soil formation, organize parent material into a soil profile that consists of soil horizons. These processes can occur over millennia; however, they can also be influenced by short-term variables such as human use. Understanding the processes enables interpretation of the natural history of a soil and provides a starting point to evaluate how future changes will affect the soil resource. Combining landscape history with knowledge of principles of soil profile development allows for more precise and effective land use planning, from residential development to precision agricultural practices. At the completion of this lesson, students will be able to do the following: 1. Describe the four major soil forming processes. 2. Describe how these four processes redistribute soil materials in vertical and horizontal dimensions. 3. Explain which soil processes are dominant in each soil horizon. 4. Develop a profile horizon sequence based on given soil properties and a set of soil forming factors 5. Describe the general soil forming processes based on the soil forming factors that led to the development of a given soil profile. The lesson is written to target educational needs of lower-level undergraduate students and is open for use by the public and educational institutions

Soil genesis and development, lesson 3: Soil forming factors

This lesson explores the five major factors of soil formation—(1) climate, (2) organisms, (3) time, (4) topography, and (5) parent material—and their influence in forming soil. The distinction between active and passive factors, moisture and temperature regimes, organism and topographic influences, and parent material sources are described. At the completion of this lesson, students will be able to do the following: 1. Identify the five factors of soil formation. 2. Explain the effects of each of the factors on soil formation. 3. Explain how types of parent material differ in terms of mode of deposition and degree of sorting. The lesson is written to target educational needs of lower-level undergraduate students and is available for use by the public and educational institutions

Soil genesis and development, lesson 2: Weathering processes of rocks and minerals

Weathering of rocks and minerals, which include physical, chemical, and biological processes, contributes to the development of soil. The degree of weathering depends not only on the rock and mineral composition but also on climate and biological activities. Experiential learning activities for different global regions support the learning objectives. At the completion of this lesson, students will be able to do the following: 1. Describe how climatic factors influence the weathering of rocks and minerals. 2. Define and distinguish physical, chemical, and biological weathering processes. The lesson is written to target educational needs of lower-level undergraduate students in earth and environmental sciences and is available for use by the public and educational institutions