Search

This laboratory experiment describes the preparation of a N-protected phenylalanine ethyl ester by a zinc-mediated Mannich-like multicomponent reaction between benzyl bromide, "p"-anisidine, and ethyl glyoxylate. The one-step reaction involves the in situ metallation of benzyl bromide into a benzylzinc reagent and its addition onto imine (Barbier conditions). The multicomponent procedure is suitable for a 4-to-5 h undergraduate organic laboratory. (Contains 1 figure and 2 schemes.)

We present the first large-scale, high-resolution spatial and temporal pattern of disease mortality caused by Ostreid herpesvirus 1 (OsHV-1) that has affected Pacific oyster Crassostrea gigas in France every year since 2008, in relation to local farm use. Mortality was monitored in healthy oyster spat deployed at 106 locations in the Thau Mediterranean lagoon during the epizootic that occurred in spring 2011. We conducted a field survey of farming practices in the areas where the sentinel oysters were placed before the epizootic. We found that the risk of disease mortality in sentinel oysters was higher within the bivalve farming area than outside it, suggesting that the infection pressure is much higher in areas with intensive farming activity. The risk of mortality was higher in farms rearing spat, a developmental stage particularly susceptible to OsHV-1, than in farms rearing adult oysters, which are generally more resistant. Additionally, the mortality risk in farms rearing adult animals was similar to that in empty farms, which suggests that, during the study period, adult oysters did not vector the disease. Interestingly, the mortality risk for sentinel oysters deployed in mussel Mytilus galloprovincialis farms was lower than for those held in oyster farms or empty farms, suggesting that mussels reduced the infection pressure on susceptible oysters.

One of the most exciting issues in psychology is, What are the psychological mechanisms underlying human tool use? The computational approach assumes that the use of a tool (e.g., a hammer) requires the extraction of sensory information about object properties (heavy, rigid), which can then be translated into appropriate motor outputs (grasping, hammering). The ecological approach suggests that humans perceive not the properties of tools per se but what they afford (a heavy, rigid object affords pounding). This is the theory of affordances. In this article, we examine the potential of the computational view and the ecological view to account for human tool use. To anticipate our conclusions, neither of these approaches is likely to be satisfactory, notably because of their incapacity to resolve the issue of why humans spontaneously use tools. In response, we offer an original theoretical framework based on the idea that affordance perception and technical reasoning work together in a dialectical way. The thesis we defend here is that humans have the ability to view body action as a problem to be solved. It is precisely at this point that technical reasoning occurs. However, even if the ability to do technical reasoning gives humans the illusion of constantly doing less (e.g., TV remote control), they are still forced to use body action--and to perceive affordances--to operate the product of the reasoning (pushing buttons with the fingers). This is the principle of dialectic. (Contains 10 footnotes, 1 table, and 4 figures.)

Seventy-two first-, third-, and fifth-grade Black children heard stories about Black and White students engaged in computer, physical education, social studies, and spelling tasks at school. Children were asked to evaluate the ability, effort, experience of task difficulty, and likelihood of task success for the story characters. Findings indicated that the effect of character's race and sex on the children's evaluations varied across task domains and type of judgment being made. Children judged that females would need more effort than males would need to learn the social studies material. For the computer task, racial in-group favoritism was suggested by findings that Blacks would need less effort to learn the task than Whites. In-group favoritism based on the learner's sex was suggested by girls' attribution of more ability to females than to males for the computer task. Implications of these findings for the continued study of academic achievement stereotypes of Black students are discussed. (Contains 3 figures and 2 tables.)

Peer relations, academic competence, and help-seeking behaviors of Black elementary school children were examined. Results indicated that, in comparison to boys, girls were preferred more as helpers, were perceived to be more academically competent, and sought help from peers more often. The distribution of boys and girls across different peer sociometric status groups (i.e., popular, rejected, average) in the classrooms did not differ nor was status in the classroom peer group related to the frequency of children's help seeking. The use of help seeking is suggested to be highly compatible with traditional culturally-based achievement styles of Blacks. Implications of the findings for promoting school adjustment and achievement in Black elementary students are discussed. (Contains 2 tables.)

Fifty-three fourth- and fifth-grade Black American students completed questionnaire measures of their preferences for working cooperatively, competitively, and individualistically in their homes and classrooms. Students' perceptions of family members' and teachers' approval of each type of behavior were also measured. Students perceived that adults approved of cooperative behaviors regardless of gender and context. However, there were gender differences in perceived adult approval of competitive or individualistic behaviors. Boys reported more approval for competitive and individualistic behaviors in both contexts than girls did. Additionally, girls and boys had similar desires to work competitively at school. Results were interpreted as demonstrating that both contexts fostered competition and independence in boys more than in girls. (Contains 2 tables.) [This article is based on a thesis by the first author that was completed under the supervision of the second author and submitted to the University of Pittsburgh in partial fulfillment of the requirements of the Masters of Science degree.]

Pruritus (or itch) is an unpleasant sensation leading to a desire to scratch. In the epidermis, there are selective C or Aδ epidermal nerve endings that are pruriceptors. At their other ends, peripheral neurons form synapses with spinal neurons and interneurons. Many areas in the central nervous system are involved in itch processing. Although itch does not occur solely because of parasitic, allergic, or immunologic diseases, it is usually the consequence of neuroimmune interactions. Histamine is involved in a minority of itchy conditions, and many other mediators play a role: cytokines (eg, IL-4, IL-13, IL-31, IL-33, and thymic stromal lymphopoietin), neurotransmitters (eg, substance P, calcitonin gene-related peptide, vasoactive intestinal peptide, neuropeptide Y, NBNP, endothelin 1, and gastrin-releasing peptide), and neurotrophins (eg, nerve growth factor and brain-derived neurotrophic factor). Moreover, ion channels such as voltage-gated sodium channels, transient receptor potential vanilloid 1, transient receptor ankyrin, and transient receptor potential cation channel subfamily M (melastatin) member 8 play a crucial role. The main markers of nonhistaminergic pruriceptors are PAR-2 and MrgprX2. A notable phenomenon is the sensitization to pruritus, in which regardless of the initial cause of pruritus, there is an increased responsiveness of peripheral and central pruriceptive neurons to their normal or subthreshold afferent input in the context of chronic itch. [ABSTRACT FROM AUTHOR]

Copyright of Ethnologie Française is the property of Presses Universitaires de France and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Display omitted] • 3D stereo-reconstruction from Pleiades satellite imagery. • Structural analysis and measurements from high-resolution Pleiades DEM and orthoimage. • Large-scale geological exploration of the organization of the Afar-Yemen volcanic sequences. • Volcanic passive margin development and related geodynamics. We have mapped Oligocene to Quaternary volcanic sequences, emplaced across the Afar magmatic province (AMP: Ethiopia, Eritrea, Djibouti, Yemen), by using 50 cm resolution Pleiades satellite images. Systematic and precise measurements of flow sequences between Djibouti and SW Yemen focus on variations in lava dips and dip directions. From these results, we are able to infer the volcano-tectonic architecture of the upper crust across the southern part of the Afar magmatic province and the evolution of crustal deformation over time. Our results provide evidence that post-trap volcanism within the Afar area was emplaced during the stretching of continental crust, mostly as seaward dipping reflector (SDR) -type volcanic wedges, commonly observed along volcanic passive margins. Compilation of our results with published ages and structures of volcanic sequences in western Afar and Djibouti allows us to map these SDR wedges along a 700 km-long crustal cross-section between the Ethiopia and SW Yemen escarpments. During the Late Oligocene to Lower Miocene, Inner SDR-type wedges developed during the formation of two crustal necking zones on either sides of an uplifted and weakly deformed crustal Danakil C-Block. Following this early extensional event, the C-Block was further stretched and thinned during the development of two transient continental rift axes, the Bab al Mandab to the East and the Afar axis to the West, thought to have been concomitantly active until ∼5 Ma. From Pliocene onwards, rifting focalized W of the Danakil Block. NE-ward diverging wedges of Inner SDRs developed during the Stratoïd volcanic event throughout the whole Afar Depression, along with an onset of continental extension at the tip of a westward propagating Aden rift. A late radical change in tectonics occurred when the Aden Rift propagated into the Afar, immediately before the onset of a slow-spreading oceanic system. [ABSTRACT FROM AUTHOR]