Competition between Lythrum salicaria and a rare species: combining evidence from experiments and long-term monitoring

The rare endemic plant Sidalcea hendersonii (Henderson's checker-mallow) occurs in tidal marshes of the Pacific Northwest and may be threatened by Lythrum salicaria (purple loosestrife), a European invader plant. We compared the abundances of Lythrum and Sidalcea in a wetland in British Columbia (Canada) in 1999 to those measured in 1979 to track changes in both species. Although the frequency of Sidalcea decreased by more than 50%, and that of Lythrum increased by almost 20%, there was no significant relationship between the changes of the two species. We assessed the potential effects of competition by Lythrum on Sidalcea in field and patio experiments. In the field, we measured the response of Sidalcea to the removal of Lythrum over a two-year period and compared this to the response of Sidalcea to the removal of native species and in unmanipulated control plots. Removal of Lythrum significantly improved the vegetative performance of Sidalcea compared to the removal of randomly selected native plants and the control treatment in the first year. In the second year, the performance of Sidealcea did not differ significantly with treatment. Removals did not influence the reproductive performance of Sidalcea in either year. A one-year additive experiment, carried out in pots, compared the competitive effect of Lythrum on Sidalcea with that of two native species. Lythrum's impact on Sidalcea was not consistently stronger than that of the native species. Collectively, these results do not indicate a strong impact of Lythrum on the reproduction or abundance of Sidalce

Power-cadence relationship in endurance cycling

In maximal sprint cycling, the power-cadence relationship to assess the maximal power output (P max) and the corresponding optimal cadence (C opt) has been widely investigated in experimental studies. These studies have generally reported a quadratic power-cadence relationship passing through the origin. The aim of the present study was to evaluate an equivalent method to assess P max and C opt for endurance cycling. The two main hypotheses were: (1) in the range of cadences normally used by cyclists, the power-cadence relationship can be well fitted with a quadratic regression constrained to pass through the origin; (2) P max and C opt can be well estimated using this quadratic fit. We tested our hypothesis using a theoretical and an experimental approach. The power-cadence relationship simulated with the theoretical model was well fitted with a quadratic regression and the bias of the estimated P max and C opt was negligible (1.0W and 0.6rpm). In the experimental part, eight cyclists performed an incremental cycling test at 70, 80, 90, 100, and 110rpm to yield power-cadence relationships at fixed blood lactate concentrations of 3, 3.5, and 4mmol L−1. The determined power outputs were well fitted with quadratic regressions (R 2=0.94-0.96, residual standard deviation=1.7%). The 95% confidence interval for assessing individual P max and C opt was ±4.4W and ±2.9rpm. These theoretical and experimental results suggest that P max, C opt, and the power-cadence relationship around C opt could be well estimated with the proposed metho

Sarcomere dynamics during muscular contraction and their implications to muscle function

This article attempts to identify the key aspects of sarcomere inhomogeneity and the dynamics of sarcomere length changes in muscle contraction experiments and focuses on understanding the mechanics of myofibrils or muscle fibres when viewed as independent units of biological motors (the half-sarcomeres) connected in series. Muscle force generation has been interpreted traditionally on the basis of the kinetics of crossbridge cycling, i.e. binding of myosin heads to actin and consecutive force generating conformational change of the head, under controlled conditions and assuming uniformity of sarcomere or half-sarcomere behaviour. However, several studies have shown that re-distribution of internal strain within myofibrils and muscle fibres may be a key player, particularly, during stretch or relaxation so that force kinetics parameters are strongly affected by sarcomere dynamics. Here, we aim to shed light on how force generation, crossbridge kinetics, and the complex sarcomere movements are to be linked and which mechanical concepts are necessary to develop a comprehensive contraction model of a myofibri

Therapeutisches Nachbehandlungsschema nach einer arthroskopischen FAI-Operation

Hintergrund: Das FAI (femoralacetabuläres Impingement) ist ein höchst aktuelles Thema in der Medizin. Es betrifft vor allem junge und sportliche Patienten/-innen. Die knöcherne Anschläge können durch eine Operation oft korrigiert werden. Die funktionellen Defizite müssen postoperativ im Rehabilitationsprozess wiederhergestellt werden. Ziel: Ziel dieses Literatur-Reviews ist es, für den Rehabilitationsprozess nach einer arthroskopischen FAI Operation eine Empfehlung für die physiotherapeutische Nachbehandlung herauszugeben. Methode: Es wurde in den Datenbanken CINAHL, Cochrane, Google Books, MedLine, PEDro und PubMed nach Studien für diese Arbeit gesucht. Drei der gefundenen Studien erfüllten die Einschlusskriterien: Zwei Single Case Reports und eine Case Series. Resultate: Die beurteilten Nachbehandlungsschemas der Studien teilen den Rehabilitationsprozess in Phasen ein. Das Outcome war bei den meisten behandelten Patienten/-innen gut bis sehr gut. Die Nachbehandlungsschemen der untersuchten Schweizer Kliniken sind mit den beurteilten Nachbehandlungsschemen vergleichbar. Schlussfolgerung: Es existiert noch keine Langzeitstudie oder RTC welche die Rehabilitation der Patienten untersuchen. Im Bereich der physiotherapeutischen Nachbehandlung bei einem FAI benötigt es deshalb weitere Forschung. Die vorhandenen Nachbehandlungsschemas sind als Empfehlung zu betrachten und die gewählten Interventionen müssen kritisch Überprüft werden

Influence of road incline and body position on power-cadence relationship in endurance cycling

In race cycling, the external power-cadence relationship at the performance level, that is sustainable for the given race distance, plays a key role. The two variables of interest from this relationship are the maximal external power output (P max) and the corresponding optimal cadence (C opt). Experimental studies and field observations of cyclists have revealed that when cycling uphill is compared to cycling on level ground, the freely chosen cadence is lower and a more upright body position seems to be advantageous. To date, no study has addressed whether P max or C opt is influenced by road incline or body position. Thus, the main aim of this study was to examine the effect of road incline (0 vs. 7%) and racing position (upright posture vs. dropped posture) on P max and C opt. Eighteen experienced cyclists participated in this study. Experiment I tested the hypothesis that road incline influenced P max and C opt at the second ventilatory threshold ( $$P_{ \max }^{{{\text{VT}}_{ 2} }}$$ and $$C_{\text{opt}}^{{{\text{VT}}_{ 2} }}$$ ). Experiment II tested the hypothesis that the racing position influenced $$P_{ \max }^{{{\text{VT}}_{ 2} }}$$ , but not $$C_{\text{opt}}^{{{\text{VT}}_{ 2} }}$$ . The results of experiment I showed that $$C_{\text{opt}}^{{{\text{VT}}_{ 2} }}$$ and $$P_{ \max }^{{{\text{VT}}_{ 2} }}$$ were significantly lower when cycling uphill compared to cycling on level ground (P<0.01). Experiment II revealed that $$P_{ \max }^{{{\text{VT}}_{ 2} }}$$ was significantly greater for the upright posture than for the dropped posture (P<0.01) and that the racing position did not affect $$C_{\text{opt}}^{{{\text{VT}}_{ 2} }}$$ . The main conclusions of this study were that when cycling uphill, it is reasonable to choose (1) a lower cadence and (2) a more upright body positio

Budding yeast as a model organism to study the effects of age

Although a budding yeast culture can be propagated eternally, individual yeast cells age and eventually die. The detailed knowledge of this unicellular eukaryotic species as well as the powerful tools developed to study its physiology makes budding yeast an ideal model organism to study the mechanisms involved in aging. Considering both detrimental and positive aspects of age, we review changes occurring during aging both at the whole-cell level and at the intracellular level. The possible mechanisms allowing old cells to produce rejuvenated progeny are described in terms of accumulation and inheritance of aging factors. Based on the dynamic changes associated with age, we distinguish different stages of age: early age, during which changes do not impair cell growth; intermediate age, during which aging factors start to accumulate; and late age, which corresponds to the last divisions before death. For each aging factor, we examine its asymmetric segregation and whether it plays a causal role in aging. Using the example of caloric restriction, we describe how the aging process can be modulated at different levels and how changes in different organelles might interplay with each other. Finally, we discuss the beneficial aspects that might be associated with ag

Annuario Registro Dati 2004

In italianL\u27Annuario dati del Registro, nata nel 2004, supplemento della testata registrata Focus. it, raccoglie dati statistici e commenti relativi ad un intero anno di registrazioni e a tutte le attivit? correlate, integrata con le stime sul fenomeno della contestazione dei nomi a dominio. L\u27Annuario ? pubblicato in italiano e in inglese

The association between overweight and illegal drug consumption in adolescents is there an underlying influence of the sociocultural environment?

Background: The aims of the study were to: a) Examine the distribution of gender-stratified body mass index (BMI), eating attitudes and use of addictive substances, under the hypothesis of a confluent prevalence of weight abnormalities, eating disorders and substance abuse. b) Demonstrate the extent to which family, peer-related and psychosocial factors are common elements in categories of compulsive behaviour. Methodology/Principal Findings: In the present cross-sectional study, data were collected through self reported questionnaires administered to a large sample of 33,185 15-19 years old adolescents (ESPADHItalia), divided into weight categories based on the BMI percentile distribution. Multinomial analyses were adopted to address the influence of social, family, leisure time factors, Eating Attitude Test (EAT26) on the association between weight categories and drug use. Recent drugs use was more frequent in overweight and underweight adolescents (p,0.05), especially in females. An EAT26 score $20 was more common in overweight adolescents. Multinomial analysis abolished the relationship between overweight and the use of most drugs, implicating self-esteem, parents\u27 educational level, and friendships as mediators of the association. Within the overweight category, adolescents reporting recent drug use, showed greater frequency of having drug-abusing friends (,80%), and severe problems with parents and school (,30%) compared to overweight adolescents without recent drug use. Conclusion: The frequent association of overweight and substance use and the presence of common underlying social factors, highlights the need for an interdisciplinary approach involving individual-focused treatment models as well as public health, social and environmental changes to reduce food- and substances-related problems.

Italian Report: EMCDDA Project (CC.09.EPI.002)

Although there are definitions and diagnostic criteria to identify cannabis abuse and dependence, there is no a shared concept of cannabis use related problems. In recent times a number of indicators have been discussed and implemented (use severity and consumption patterns, treatment demands etc) and there are different screening instruments used to measure negative consequences of cannabis use. Short screening scales to assess dependence and other problems related to the use of cannabis seem to be usefull instruments, easy to be administered, to estimate prevalence of cannabis related negative consequences and to identify at risk-persons. The need to standardize also in Italy a set of instruments which allow to monitor problematic cannabis use patterns or addiction development, has been highlighted. The three scales Cannabis Abuse Screening Test (CAST), Severity of Dependence Scale (SDS) and Munich Composite International Diagnostic Interview (M-CIDI) are included in the questionnaire used in ESPAD-Italia? 2009 survey. The present work considers the validation process of these instruments in high school population.not availabl

Instabilities and Oscillations in Isotropic Active Gels

We present a generic formulation of the continuum elasticity of an isotropic crosslinked active gel. The gel is described by a two-component model consisting of an elastic network coupled frictionally to a permeating fluid. Activity is induced by active crosslinkers that undergo an ATP-activated cycle and transmit forces to the network. The on/off dynamics of the active crosslinkers is described via rate equations for unbound and bound motors. For large activity motors yield a contractile instability of the network. At smaller values of activity, the on/off motor dynamics provides an effective inertial drag on the network that opposes elastic restoring forces, resulting in spontaneous oscillations. Our work provides a continuum formulation that unifies earlier microscopic models of oscillations in muscle sarcomeres and a generic framework for the description of the large scale properties of isotropic active solids.Comment: 13 pages, 5 figure