Age related changes in skeletal muscle activation following short-term resistance training.

Current research suggests that older adults do not possess the same ability to fully activate skeletal muscle of the lower limb as do young adults. However, it is not known at what age these changes may negatively affect the improvement in neuromuscular activation associated with resistance training. Purpose. To determine the effects of short-term resistance training on measures of muscular strength and skeletal muscle activation of the triceps surae in adult males ranging from 20-79 years of age. Methods. Forty-six normal healthy males volunteered to participate in this research study. Subjects were designated into one of five groups, classified as individuals aged between 20-29 years (n=10), 30-39 years (n=10), 40-49 years (n=7), 50-59 years (n=9), and 60-79 years (n=10). Subjects participated in three supervised resistance training sessions over the course of seven days, performing four lower body exercises during each training session. Subjects were assessed for muscle cross-sectional area, muscular strength, and muscle activation via twitch interpolation and surface electromyography (SEMG) before and after the experimental training. Three-way and two-way repeated measures ANOVA, as well as a one-way ANOVA, was used to determine group differences and changes with training. Results. Analysis of baseline muscular strength data revealed only a significant difference (p=0.02) in muscle strength between Group 2, 30-39 years (132.4 +/- 5.4) and Group 5, 60-79 years (99.8 +/- 7.5) for plantarflexion maximal strength. No significant differences (p>0.05) were observed for muscle cross-sectional area, dorsiflexion muscular strength, muscle activation assessed via twitch interpolation, or antagonist co-activation between age groups. Statistical analysis revealed no significant differences (p>0.05) in SEMG RMS amplitude or median frequency between age groups. However, comparison of muscle groups revealed a significant difference (p=0.003) in RMS amplitude between the soleus (SOL; 145.8 +/- 10.2 muV) and medial gastrocnemius (MG; 254.2 +/- 17.7 muV) muscles. Following training, there was no significant change (p>0.05) in muscle cross-sectional area, muscular strength, muscle activation assessed via twitch interpolation, or antagonist co-activation for any age group. Examination of SEMG data determined significant main effects for muscle group (p=0.001) and time (p=0.013) between SOL and MG for RMS amplitude. A significant decrease for the time main effect (p=0.001) in SEMG median frequency was also observed post-training. Conclusions. A similar pattern of response in all groups was observed in most variables assessed during the present study. The results from the present study indicated that there were no significant pre-test to post-test changes in muscle size, muscular strength, muscle activation, or antagonist co-activation following the experimental training period. These findings were unlike those from previous investigations of the leg extensors t hat have reported increases in performance after only two or three training sessions. This information may be useful for those involved in rehabilitative programs. Specifically, the muscles of the lower limb (i.e. calf) could require more than three training sessions to elicit the strength improvements and neuromuscular adaptations that typically occur during the early stages of a resistance training program

Assessing the construct validity of the situational test of emotional management.

The current study examined the construct validity of the Situational Test of Emotional Management (STEM), a newly developed measure of emotional intelligence. A logistic regression approach was utilized to assess the STEM, at the item-level, on two factors, gender and Extraversion. It was hypothesized a logistic model including gender and Extraversion would significantly predict classification of participants into two groups (correct response on STEM items and incorrect response on STEM items) beyond a simple intercept-only logistic regression. Data analysis revealed that the gender and Extraversion did not significantly enhance the classification rates of participants into the two groups, but gender was a significant univariate influence on four items. Explanations as to why the hypothesis was not fully supported are discussed, as well as avenues for future research

Planning in Small vs. Large Businesses: Do Managers Prefer Different Tools?

 Evidence that large and small businesses approach problems differently has raised ques- tions concerning the validity of applying large business prescriptions to small businesses. This issue was addressed bypresenting both large and small business planners with planning prob- lems differing in environmental volatility, system adaptation and nature of planning re- quirements. Different combinations of these factors were used togenerate twelve distinct plan- ning situations. Eight information processing aids were identified that have been described in the literature as planning tools. Each aid has been prescribed to be more appropriate for use in some planning situations than in others. The research tested hypotheses that planners in specific situations would use planning aids prescr ibed for those situations and that large and small business planners would approach the problems differently. Results are interpreted as indicating that use of planning aids does not correspond closely to the theoretical prescrip- tions but that other implicittheories may be operating and the implicit theories used in small businesses may be different than those used inlarge organizations

Selection and Certification of TPS: Constraints and Considerations of Venus Missions

This presentation was part of the session : Probe Missions to the Giant Planets, Titan and VenusSixth International Planetary Probe WorkshopThe science community currently has interest in planetary entry probe missions to improve our understanding of the atmosphere of Saturn [1], missions to Venus and also sample return missions from comets and asteroids. In addition, the In-Space Propulsion Program has completed aerocapture mission design studies that have defined the requirements for the Thermal protection System (TPS) to Venus, Mars, Titan and Neptune. There have been investments in new TPS materials and to revive flight qualified materials such as PICA (used on Stardust and currently baselined for MSL and Orion) and Carbon-Phenolic, the TPS material of choice for Venus and Outer Planet missions. Mission studies have shown the heating rates for the "shallow" Saturn probes are in the range of (2 - 5) KW/cm2 in its H(2)/He atmosphere. Venus entry probes will experience heat fluxes in the similar range of (3 - 7) kW/cm(2) in CO2. High-speed Earth reentry missions from comets and asteroids will experience heating of the range of (1 - 5) kW/cm(2) and at pressures equal to or higher than Stardust. Aerocapture during Venus missions will experience heat fluxes in the range of (2 - 4) kW/cm(2) in CO2. Titan aero-capture missions will experience far smaller heating fluxes in the N2/methane atmosphere. Since the flight times are longer during aerocapture missions, TPS design requirements involve much larger heatloads at relatively lower heat-fluxes compared to those for direct entry probe missions. It is clear that qualification and certification of the heritage ablative materials or the development of new, ablative Thermal Protection System (TPS) materials for entry or aerocapture probe missions is needed [2] and the challenges are in testing, especially in the appropriate atmospheric gases. NASA Ames has nearly completed the construction of a small, low cost, 5 MW arc jet facility, called the Development Arcjet Facility (DAF) that will permit testing of small models at high heat fluxes and in different gases. This paper will review the entry conditions from a collection of mission studies to various solar system destinations, the testing needs of both newer as well as heritage TPS for each destination and provide the approach, we at NASA Ames plan to adopt, in testing and analysis by making use of both existing arc jet facilities as well as an affordable, small 5 MW arc jet that can be used for TPS development in test gases appropriate for the Neptune, Titan, Saturn, Venus or Earth applications. [1] Atreya, S. K., et. al. "Formation of Giant Planets and Their Atmospheres: Entry Probes for Saturn and Beyond; 5 th International Planetary Probe Workshop, June 25-29, Bordeaux, France. [2] Venkatapathy, E. and Laub, B. "Requirements for Development of Thermal Protection Systems for Multiple Missions: 5th International Planetary Probe Workshop, June 25-29, Bordeaux, France.NASA In-Space Propulsion Progra

A regularisation approach to causality theory for C^{1,1}Lorentzian metrics

We show that many standard results of Lorentzian causality theory remain valid if the regularity of the metric is reduced to C^{1,1}. Our approach is based on regularisations of the metric adapted to the causal structure

Neutron Vibrational Spectroscopy and First-Principles Calculations of the Ternary Hydrides Li\u3csub\u3e4\u3c/sub\u3eSi\u3csub\u3e2\u3c/sub\u3eH(D) and Li\u3csub\u3e4\u3c/sub\u3eGe\u3csub\u3e2\u3c/sub\u3eH(D): Electronic Structure and Lattice Dynamics

Using combined neutron spectroscopy and first-principles calculations, we investigated the electronic structure and vibrational dynamics of the recently discovered class of ternary hydrides Li4Tt2H (Tt=Si and Ge). In these compounds, all hydrogen atoms are located in a single type of Li6-defined octahedral site. The Tt atoms form long-range Tt-Tt chains sandwiched between each Li6-octahedra layer. The Li-H interactions are strongly ionic, with bond lengths comparable to those in LiH. Our density functional theory calculations indicate that Li atoms transfer their electrons to both H and Tt atoms. Tt atoms within the Tt-Tt chain are bonded covalently. The electronic density of states reveals that both hydrides exhibit metallic behavior. The observed vibrational spectra of these hydrides are in good overall agreement with the calculated phonon modes. There is evidence of dispersion induced splitting in the optical phonon peaks that can be ascribed to the coupling of H vibrations within the Li6-octahedra layers

Ethylene-mediated nitric oxide depletion pre-adapts plants to hypoxia stress

Timely perception of adverse environmental changes is critical for survival. Dynamic changes in gases are important cues for plants to sense environmental perturbations, such as submergence. In Arabidopsis thaliana, changes in oxygen and nitric oxide (NO) control the stability of ERFVII transcription factors. ERFVII proteolysis is regulated by the N-degron pathway and mediates adaptation to flooding-induced hypoxia. However, how plants detect and transduce early submergence signals remains elusive. Here we show that plants can rapidly detect submergence through passive ethylene entrapment and use this signal to pre-adapt to impending hypoxia. Ethylene can enhance ERFVII stability prior to hypoxia by increasing the NO-scavenger PHYTOGLOBIN1. This ethylene-mediated NO depletion and consequent ERFVII accumulation pre-adapts plants to survive subsequent hypoxia. Our results reveal the biological link between three gaseous signals for the regulation of flooding survival and identifies key regulatory targets for early stress perception that could be pivotal for developing flood-tolerant crops

Alpine ice and the annual political economy of the Angevin Empire, from the death of Thomas Becket to Magna Carta, c. AD 1170–1216

High-resolution analysis of the ice core from Colle Gnifetti, Switzerland, allows yearly and sub-annual measurement of pollution for the period of highest lead production in the European Middle Ages, c. AD 1170–1220. Here, the authors use atmospheric circulation analysis and other geoarchaeological records to establish that Britain was the principal source of that lead pollution. The comparison of annual lead deposition at Colle Gnifetti displays a strong similarity to trends in lead production documented in the English historical accounts. This research provides unique new insight into the yearly political economy and environmental impact of the Angevin Empire of Kings Henry II, Richard the Lionheart and John

Surveillance indicators for potential reduced exposure products (PREPs): developing survey items to measure awareness

<p>Abstract</p> <p>Background</p> <p>Over the past decade, tobacco companies have introduced cigarettes and smokeless tobacco products (known as Potential Reduced Exposure Products, PREPs) with purportedly lower levels of some toxins than conventional cigarettes and smokeless products. It is essential that public health agencies monitor awareness, interest, use, and perceptions of these products so that their impact on population health can be detected at the earliest stages.</p> <p>Methods</p> <p>This paper reviews and critiques existing strategies for measuring <it>awareness </it>of PREPs from 16 published and unpublished studies. From these measures, we developed new surveillance items and subjected them to two rounds of cognitive testing, a common and accepted method for evaluating questionnaire wording.</p> <p>Results</p> <p>Our review suggests that high levels of awareness of PREPs reported in some studies are likely to be inaccurate. Two likely sources of inaccuracy in awareness measures were identified: 1) the tendency of respondents to misclassify "no additive" and "natural" cigarettes as PREPs and 2) the tendency of respondents to mistakenly report awareness as a result of confusion between PREPs brands and similarly named familiar products, for example, Eclipse chewing gum and Accord automobiles.</p> <p>Conclusion</p> <p>After evaluating new measures with cognitive interviews, we conclude that as of winter 2006, awareness of reduced exposure products among U.S. smokers was likely to be between 1% and 8%, with the higher estimates for some products occurring in test markets. Recommended measurement strategies for future surveys are presented.</p