Aphidius ervi Haliday is a parasitoid of natural populations of both Acyrthosiphon pisum (Harris) on alfalfa and Sitobion avenae (Fabricius) on wheat in Chile. In this study the performance of the aphid parasitoid on both host species was evaluated. Regardless of origin, both females and males of A. ervi were significantly smaller when reared on S. avenae than on A. pisum. Males and females of A. ervi reared on S. avenae on wheat also took significantly longer to develop than when reared on A. pisum. There was no significant difference in the sex ratio of the parasitoid when reared on these two host aphids. Survival of parasitoids from the A. pisum - alfalfa system was significantly lower when reared on S. avenae relative to those reared on A. pisum, but no significant difference in survival on both hosts was detected in parasitoids from the S. avenae - wheat system. Behaviour of parasitoid females during oviposition, such as frequency of encounters, number of attacks and stabbings of host aphids, were significantly higher in the A. pisum - A. ervi interaction than in the S. avenae - A. ervi interaction, regardless of the origin of the parasitoid. Aphid defensive reactions such as kicking or production of cornicle secretion, were significantly higher in the A. pisum - A. ervi than the S. avenae - A. ervi interaction. The results are discussed in relation to the effect of host quality and host aphid body size on parasitoid development.
In this study we have evaluated the effect of maximal incremental cycling exercise (IE) on the systemic release of prostacyclin (PGI2), assessed as plasma 6-keto-PGF1α concentration in young healthy men. Eleven physically active - untrained men (mean ± S.D.) aged 22.7 ± 2.1 years; body mass 76.3 ± 9.1 kg; BMI 23.30 ± 2.18 kg · m-2; maximal oxygen uptake (VO2max) 46.5 ± 3.9 ml · kg-1 · min-1, performed an IE test until exhaustion. Plasma concentrations of 6-keto-PGF1α, lactate, and cytokines were measured in venous blood samples taken prior to the exercise and at the exhaustion. The net exercise-induced increase in 6-keto-PGF1α concentration, expressed as the difference between the end-exercise minus pre-exercise concentration positively correlated with VO2max (r=0.78, p=0.004) as well as with the net VO2 increase at exhaustion (r=0.81, p=0.003), but not with other respiratory, cardiac, metabolic or inflammatory parameters of the exercise (minute ventilation, heart rate, plasma lactate, IL-6 or TNF-α concentrations). The exercise-induced increase in 6-keto-PGF1α concentration was significantly higher (p=0.008) in a group of subjects (n=5) with the highest VO2max when compared to the group of subjects with the lowest VO2max, in which no increase in 6-keto-PGF1α concentration was found. In conclusion, we demonstrated, to our knowledge for the first time, that exercise-induced release of PGI2 in young healthy men correlates with VO2max, suggesting that vascular capacity to release PGI2 in response to physical exercise represents an important factor characterizing exercise tolerance. Moreover, we postulate that the impairment of exercise-induced release of PGI2 leads to the increased cardiovascular hazard of vigorous exercise., J. A. Zoladz ... [et al.]., and Obsahuje seznam literatury
The interval model training has been more recommended to promote aerobic adaptations due to recovery period that enables the execution of elevated intensity and as consequence, higher workload in relation to continuous training. However, the physiological and aerobic capacity adaptations in interval training with identical workload to continuous are still uncertain. The purpose was to characterize the effects of chronic and acute biomarkers adaptations and aerobic capacity in interval and continuous protocols with equivalent load. Fifty Wistar rats were divided in three groups: Continuous training (GTC), interval training (GTI) and control (CG). The running training lasted 8 weeks (wk) and was based at Anaerobic Threshold (AT) velocity. GTI showed glycogen super-compensation (mg/100 mg) 48 h after training session in relation to CG and GTC (GTI red gastrocnemius (RG)=1.41±0.16; GTI white gastrocnemius (WG)=1.78±0.20; GTI soleus (S)=0.26±0.01; GTI liver (L)=2.72±0.36; GTC RG=0.42±0.17; GTC WG=0.54±0.22; GTC S=0.100±0.01; GTC L=1.12±0.24; CG RG=0.32±0.05; CG WG=0.65±0.17; CG S=0.14±0.01; CG L=2.28±0.33). The volume performed by GTI was higher than GTC. The aerobic capacity reduced 11 % after experimental period in GTC when compared to GTI, but this change was insignificant (19.6±5.4 m/min; 17.7±2.5 m/min, effect size = 0.59). Free fatty acids and glucose concentration did not show statistical differences among the groups. Corticosterone concentration increased in acute condition for GTI and GTC. Testosterone concentration reduced 71 % in GTC immediately after the exercise in comparison to CG. The GTI allowed positive adaptations when compared to GTC in relation to: glycogen super-compensation, training volume performed and anabolic condition. However, the GTI not improved the aerobic performance., G. G. de Araujo, C. A: Gobatto, M. Marcos-Pereira, I. G. M. Dos Reis, R: Verlengia., and Obsahuje bibliografii
The study deals with tomboyism from the perspective of past and current psychological and sociological research, and proposes a new approach to this liminal phenomenon operating in -between binary opposites of traditional femininity and masculinity. This approach makes use of intersectional analysis developed by feminists of colour to address interlocking systems of oppression based on both race and gender, and combines it with the issue of performance and the notion of identity as fluid. It also challenges usual interpretations of tomboy narratives, as is shown on the analysis of two films with tomboyish characters – Robert Mulligan’s To Kill a Mockingbird (1962) and Céline Sciamma’s Tomboy (2011)., Veronika Klusáková., and Obsahuje bibliografii
The article deals with the Victor Turner’s anthropology of pilgrimage in the light of the journey to Compostela. First, an introduction to the concept of rites de passage and communitas is given. The following is a description of the Way of Saint James, its medieval and postmodern forms. The core of the study lies in the comparison of the ethnohistoric as well as ethnographic data and corresponding pilgrims’ competing discourses with the theory. It is argued that communitas may be conceived as a structuralist, sociological or psychological phenomenon, and that all of these levels may be included in the pilgrimage. Nevertheless, it is sustained that it depends on various circumstances and multiple discourses that operate and interact in the pilgrimage process. Finally, three Turner’s topics are stressed to be useful in the present anthropology of pilgrimage: the experience as subjective feeling, bodily practice, and sensual enjoyment. Using the arguments of Halbwachs, Bruner, Connerton or Stoller, a shift from general ideas, norms, values, systems and structures to specific images, feelings, experiences and goals is recognized. Thereby the Turner’s anthropology of performance and experience is situated within the particular direction of the postmodern turn and recent social theory.
Performance of any machine tool is, under certain technological conditions, limited by chatter, which occurs during machining. The limit between machining without and with chatter is called limit of stability. It is expressed by so called stable depth of cut, which is defíned under certain conditions. The article deals with the investigation of optimal modal parameters for machine tool models. The criterion for this optimum is the highest limit of stability.