Training with power measurement: a new era in cycling training

Journal ArticlePROVIDING CYCLISTS WITH A reliable measure of exercise intensity presents unique challenges. Environmental factors such as wind speed, road grade and surface texture, and air density interactively influence the resistance encountered during cycling and thus alter the speed a cyclist can maintain while riding at any specific intensity. For example, a cyclist might be capable of averaging 40 km/h in a tailwind with very little effort, but might be unable to maintain 20 km/h when climbing a hill at maximal effort

Understanding sprint-cycling performance: the integration of muscle power, resistance, and modeling

pre-printSprint-cycling performance is paramount to competitive success in over half the world-championship and Olympic races in the sport of cycling. This review examines the current knowledge behind the interaction of propulsive and resistive forces that determine sprint performance. Because of recent innovation in field power-measuring devices, actual data from both elite track- and road-cycling sprint performances provide additional insight into key performance determinants and allow for the construction of complex models of sprint-cycling performance suitable for forward integration. Modeling of various strategic scenarios using a variety of field and laboratory data can highlight the relative value for certain tactically driven choices during competition

Using Electronic Drug Monitor Feedback to Improve Adherence to Antiretroviral Therapy Among HIV-Positive Patients in China

Effective antiretroviral therapy (ART) requires excellent adherence. Little is known about how to improve ART adherence in many HIV/AIDS-affected countries, including China. We therefore assessed an adherence intervention among HIV-positive patients in southwestern China. Eighty subjects were enrolled and monitored for 6 months. Sixty-eight remaining subjects were randomized to intervention/control arms. In months 7–12, intervention subjects were counseled using EDM feedback; controls continued with standard of care. Among randomized subjects, mean adherence and CD4 count were 86.8 vs. 83.8% and 297 vs. 357 cells/μl in intervention vs. control subjects, respectively. At month 12, among 64 subjects who completed the trial, mean adherence had risen significantly among intervention subjects to 96.5% but remained unchanged in controls. Mean CD4 count rose by 90 cells/μl and declined by 9 cells/μl among intervention and control subjects, respectively. EDM feedback as a counseling tool appears promising for management of HIV and other chronic diseases.Boston University and the Office of Health and Nutrition of the United States Agency for International Development (GHS-A-00-03-00030-00); World Health Organization; United States Centers for Disease Control; National Institutes of Health, National Institute of Allergy and Infectious Diseases (K23 AI 62208); Mid-Career Mentoring Award (K24 RR020300

Depressive Symptoms and Health-Related Quality of Life Among Participants in the Pasos Adelante Chronic Disease Prevention and Control Program, Arizona, 2005-2008

Introduction Chronic diseases are the leading causes of death in the United States and have been associated with depressive symptoms and poor health-related quality of life (HRQOL). This study examined whether depressive symptoms and HRQOL indicators changed among participants in Pasos Adelante, a chronic disease prevention and control program implemented in a US–Mexico border community. Methods Pasos Adelante was a 12-week promotora-led program that included educational sessions and walking groups. We used the Centers for Epidemiologic Studies Depression Scale (CES-D) and the Center for Disease Control’s “Healthy Days” measures to measure depressive symptoms and HRQOL. We used linear mixed-effects models and general estimating equations to analyze changes in CES-D scores and HRQOL indicators from baseline to postprogram and from postprogram to 3-month follow-up. Results At baseline, participants had a mean of 7.1 physically unhealthy days, 7.4 mentally unhealthy days, and 3.9 days of activity limitation. The mean number of physically and mentally unhealthy days declined significantly from baseline to postprogram, but the mean number of activity limitation days did not. At baseline, 42.6% of participants reported their health as fair/poor; 20.8% of participants reported frequent mental distress, and 31.8% had a CES-D score of 16 or more. All 3 proportions declined from baseline to postprogram. No significant changes occurred between postprogram and follow-up. Conclusion Participants in Pasos Adelante showed improvement in depressive symptoms and several HRQOL indicators. Future studies should use an experimental design with a comparison group to determine whether these findings can be replicated and to examine potential mediators and moderators of program effects

The XMM Cluster Survey: a massive galaxy cluster at z = 1.45

We report the discovery of XMMXCS J2215.9-1738, a massive galaxy cluster at z=1.45, which was found in the XMM Cluster Survey. The cluster candidate was initially identified as an extended X-ray source in archival XMM data. Optical spectroscopy shows that six galaxies within a ~60" diameter region lie at z=1.45+/-0.01. Model fits to the X-ray spectra of the extended emission yield kT=7.4+2.7-1.8 keV (90% confidence); if there is an undetected central X-ray point source, then kT=6.5+2.6-1.8 keV. The bolometric X-ray luminosity is LX=4.4+0.8-0.6C 1044 ergs s-1 over a 2 Mpc radial region. The measured TX, which is the highest for any known cluster at z>1, suggests that this cluster is relatively massive for such a high redshift. The redshift of XMMXCS J2215.9-1738 is the highest currently known for a spectroscopically confirmed cluster of galaxies

Effectiveness of the Pasos Adelante Chronic Disease Prevention and Control Program in a US-Mexico Border Community, 2005-2008

Introducción "Pasos Adelante" es un programa de intervención sobre hábitos saludables facilitado por trabajadores de salud comunitaria o"promotores de salud" destinado a prevenir y controlar enfermedades crónicas en mexicoamericanos. Los estudios iniciales de"Pasos Adelante" mostraron mejoras significativas en la alimentación y la actividad física autorreportadas por los participantes.Este estudio evaluó si los habitantes de una comunidad en la frontera estadounidense que participaron en el programa mostraronmejorías en determinados valores fisiológicos y si los cambios se mantuvieron en el seguimiento a los 3 meses. Métodos El programa se llevó a cabo en sesiones de 12 semanas de enero del 2005 a mayo del 2008 e incluyó grupos de caminata y clases denutrición y actividad física. Se realizaron cuestionarios, mediciones antropométricas y pruebas de laboratorio al inicio delprograma (n = 305), al final (n = 254) y en el seguimiento a los 3 meses (n = 221). Resultados Al compararse los datos iniciales de referencia con los del final del programa, los participantes mostraron reducciones en su índicede masa corporal (P= .04), circunferencia de cintura y cadera (P< .001), presión arterial diastólica y sistólica (P< .001) y colesterol total (P= .008). Ningún valor empeoró significativamente entre la conclusión del programa y el seguimiento, aexcepción de la presión arterial sistólica. Los niveles de glucosa mejoraron entre la finalización y el seguimiento del programa (P=.01). Conclusión Estos resultados sustentan los hallazgos iniciales referidos a la mejoría autorreportada por los participantes en relación conpatrones de alimentación y actividad física al mostrar cambios en medidas objetivas. Este programa basado en la evidenciademuestra el potencial de los programas de control y prevención de enfermedades crónicas llevados a cabo por promotores desalud para mejorar la salud física abordando la prevención primaria y secundaria en organizaciones y comunidades hispanas

Depressive Symptoms and Health-Related Quality of Life Among Participants in the Pasos Adelante Chronic Disease Prevention and Control Program, Arizona, 2005-2008

Introduction Chronic diseases are the leading causes of death in the United States and have been associated with depressive symptoms and poor health-related quality of life (HRQOL). This study examined whether depressive symptoms and HRQOL indicators changed among participants in Pasos Adelante, a chronic disease prevention and control program implemented in a US–Mexico border community. Methods Pasos Adelante was a 12-week promotora-led program that included educational sessions and walking groups. We used the Centers for Epidemiologic Studies Depression Scale (CES-D) and the Center for Disease Control’s “Healthy Days” measures to measure depressive symptoms and HRQOL. We used linear mixed-effects models and general estimating equations to analyze changes in CES-D scores and HRQOL indicators from baseline to postprogram and from postprogram to 3-month follow-up. Results At baseline, participants had a mean of 7.1 physically unhealthy days, 7.4 mentally unhealthy days, and 3.9 days of activity limitation. The mean number of physically and mentally unhealthy days declined significantly from baseline to postprogram, but the mean number of activity limitation days did not. At baseline, 42.6% of participants reported their health as fair/poor; 20.8% of participants reported frequent mental distress, and 31.8% had a CES-D score of 16 or more. All 3 proportions declined from baseline to postprogram. No significant changes occurred between postprogram and follow-up. Conclusion Participants in Pasos Adelante showed improvement in depressive symptoms and several HRQOL indicators. Future studies should use an experimental design with a comparison group to determine whether these findings can be replicated and to examine potential mediators and moderators of program effects

Operator-Based Truncation Scheme Based on the Many-Body Fermion Density Matrix

In [S. A. Cheong and C. L. Henley, cond-mat/0206196 (2002)], we found that the many-particle eigenvalues and eigenstates of the many-body density matrix $\rho_B$ of a block of $B$ sites cut out from an infinite chain of noninteracting spinless fermions can all be constructed out of the one-particle eigenvalues and one-particle eigenstates respectively. In this paper we developed a statistical-mechanical analogy between the density matrix eigenstates and the many-body states of a system of noninteracting fermions. Each density matrix eigenstate corresponds to a particular set of occupation of single-particle pseudo-energy levels, and the density matrix eigenstate with the largest weight, having the structure of a Fermi sea ground state, unambiguously defines a pseudo-Fermi level. We then outlined the main ideas behind an operator-based truncation of the density matrix eigenstates, where single-particle pseudo-energy levels far away from the pseudo-Fermi level are removed as degrees of freedom. We report numerical evidence for scaling behaviours in the single-particle pseudo-energy spectrum for different block sizes $B$ and different filling fractions \nbar. With the aid of these scaling relations, which tells us that the block size $B$ plays the role of an inverse temperature in the statistical-mechanical description of the density matrix eigenstates and eigenvalues, we looked into the performance of our operator-based truncation scheme in minimizing the discarded density matrix weight and the error in calculating the dispersion relation for elementary excitations. This performance was compared against that of the traditional density matrix-based truncation scheme, as well as against a operator-based plane wave truncation scheme, and found to be very satisfactory.Comment: 22 pages in RevTeX4 format, 22 figures. Uses amsmath, amssymb, graphicx and mathrsfs package

Dual-specificity phosphatase 5 controls the localized inhibition, propagation, and transforming potential of ERK signaling

Deregulated extracellular signal-regulated kinase (ERK) signaling drives cancer growth. Normally, ERK activity is self-limiting by the rapid inactivation of upstream kinases and delayed induction of dual-specificity MAP kinase phosphatases (MKPs/DUSPs). However, interactions between these feedback mechanisms are unclear. Here we show that, although the MKP DUSP5 both inactivates and anchors ERK in the nucleus, it paradoxically increases and prolongs cytoplasmic ERK activity. The latter effect is caused, at least in part, by the relief of ERK-mediated RAF inhibition. The importance of this spatiotemporal interaction between these distinct feedback mechanisms is illustrated by the fact that expression of oncogenic BRAF(V600E), a feedback-insensitive mutant RAF kinase, reprograms DUSP5 into a cell-wide ERK inhibitor that facilitates cell proliferation and transformation. In contrast, DUSP5 deletion causes BRAF(V600E)-induced ERK hyperactivation and cellular senescence. Thus, feedback interactions within the ERK pathway can regulate cell proliferation and transformation, and suggest oncogene-specific roles for DUSP5 in controlling ERK signaling and cell fate