Giardia lamblia, a protozoan parasite that causes widespread diarrheal disease, expresses a surface membrane associated lectin, taglin, which is specifically activated by limited proteolysis with trypsin, a protease that is present in abundance at the site of infection. When activated, taglin agglutinates enterocytes which are the cells to which the parasite adheres in vivo, and in addition, binds to isolated brush border membranes of these cells. These findings suggest that this lectin may be involved in the host‐parasite interaction. Taglin is (...) most specific for terminal phosphomannosyl residues and its binding to red cells is mediated by cell surface phosphate residues. Hemagglutinating activity induced by taglin is most active at pH6.5 and is dependent on divalent cations. A monoclonal antibody to taglin reacts with the surface membrane of live trophozoites and recognizes a protein of 28/30 kDa in lysates of Giardia trophozoites, by immunoblotting. This finding is confirmed by direct demonstration of lectin activity by erythrocyte binding to proteins electroblotted to nitrocellulose, which revealed specific red cell binding to giardial protein bands in the same molecular weight range as those recognized by the monoclonal antibody. (shrink)

Features of gait are determined at multiple levels, from the selection of the gait itself (e.g. walk or run) through the specific parameters utilized (stride length, frequency, etc.) to the pattern of muscular excitation. The ultimate choices are neurally determined, but what is involved with that decision process? Human locomotion appears stereotyped not so much because the pattern is predetermined, but because these movement patterns are good solutions for providing movement utilizing the machinery available to the individual (the legs and (...) their requisite components). Under different circumstances the appropriate solution may differ broadly (different gait) or subtly (different parameters). Interpretation of the neural decision making process would benefit from understanding the influences that determine the selection of the appropriate solution in any set of circumstances, including that of normal conditions. In this review we survey an array of studies that point to energetic cost as a key input to the gait coordination system, and not just an outcome of the gait pattern implemented. We then use that information to rigorously define the construct proposed by Sparrow and Newell (1998) where the effects of environment, organism and task act as constraints determining the solution set available, and the coordination pattern is then implemented under a pressure for energetic economy. Environment is defined in terms of affordances based on the ecological psychology definition of the concept and organism is defined as classic morphology and physiology based capabilities. We rely on a novel conceptualization of task that recognizes that the task goal needs to be separated from the mechanisms that achieve the goal if the motivation behind the selection of the mechanism strategy is to be exposed and understood. This reformulation of the Sparrow and Newell construct is then linked to the proposed pressure for economy by considering it as an optimization problem, where the most readily selected gait strategy will be that which achieves the task goal at (or near) the energetic minimum. (shrink)

Книга адресована специалистам в области теории познания, обществоведам, преподавателям философских дисциплин, аспирантам и студентам философских факультетов вузов, всем тем, кто интересуется данной проблемой.

В настоящей монографии проведено исследование современного техногенного развития социум и природы и их трансформации под воздействием достижений научно-технического прогресса и разрастания искусственной среды обитания человечества.

Using payment to recruit research subjects is a common practice, but it raises ethical concerns that coercion or undue inducement could potentially compromise participants’ informed consent. This is the first national study to explore the attitudes of IRB members and other human subjects protection professionals concerning whether payment of research participants constitutes coercion or undue influence, and if so, why. The majority of respondents expressed concern that payment of any amount might influence a participant’s decisions or behaviors regarding research participation. (...) Respondents expressed greater acceptance of payment as reimbursement or compensation than as an incentive to participate in research, and most agreed that subjects are coerced if the offer of payment makes them participate when they otherwise would not or when the offer of payment causes them to feel that they have no reasonable alternative but to participate . Views about undue influence were similar. We conclude that human subjects protection professionals hold expansive and inconsistent views about coercion and undue influence that may interfere with the recruitment of research participants and impede valuable research. (shrink)

A formalism is developed which admits particles faster than light and reference frames faster than light and as fast as light. It is fully consistent with the physical principles of special relativity. The necessity of introducing imaginary quantities does not arise. It does not encounter any difficulties with the principle of causality if it is reasonably interpreted.