An external focus of attention enhances manual tracking performance

The present study investigated the enhancement effects of an external focus of attention (FOA) in the context of a manual tracking task, in which participants tracked both visible and occluded targets. Three conditions were compared, which manipulated the distance of the FOA from the participant as well as the external/internal dimension. As expected, an external FOA resulted in lower tracking errors than an internal FOA. In addition, analyses of participants’ movement patterns revealed a systematic shift toward higher-frequency movements in the external FOA condition, consistent with the idea that an external FOA exploits the natural movement dynamics available during skilled action. Finally, target visibility did not influence the effect of focused attention on tracking performance, which provides evidence for the proposal that the mechanisms that underlie FOA do not depend directly on vision

Rising CO2, Climate Change, and Public Health: Exploring the Links to Plant Biology

Background: Although the issue of anthropogenic climate forcing and public health is widely recognized, one fundamental aspect has remained underappreciated: the impact of climatic change on plant biology and the well-being of human systems. Objectives: We aimed to critically evaluate the extant and probable links between plant function and human health, drawing on the pertinent literature. Discussion: Here we provide a number of critical examples that range over various health concerns related to plant biology and climate change, including aerobiology, contact dermatitis, pharmacology, toxicology, and pesticide use. Conclusions: There are a number of clear links among climate change, plant biology, and public health that remain underappreciated by both plant scientists and health care providers. We demonstrate the importance of such links in our understanding of climate change impacts and provide a list of key questions that will help to integrate plant biology into the current paradigm regarding climate change and human health

Effects of elevated atmospheric carbon dioxide on amino acid and NH 4 + -N cycling in a temperate pine ecosystem

Rising atmospheric carbon dioxide (CO 2 ) is expected to increase forest productivity, resulting in greater carbon (C) storage in forest ecosystems. Because elevated atmospheric CO 2 does not increase nitrogen (N) use efficiency in many forest tree species, additional N inputs will be required to sustain increased net primary productivity (NPP) under elevated atmospheric CO 2 . We investigated the importance of free amino acids (AAs) as a source for forest N uptake at the Duke Forest Free Air CO 2 Enrichment (FACE) site, comparing its importance with that of better-studied inorganic N sources. Potential proteolytic enzyme activity was monitored seasonally, and individual AA concentrations were measured in organic horizon extracts. Potential free AA production in soils ranged from 190 to 690 nmol N g −1  h −1 and was greater than potential rates of soil NH 4 + production. Because of this high potential rate of organic N production, we determined (1) whether intact AA uptake occurs by Pinus taeda L., the dominant tree species at the FACE site, (2) if the rate of cycling of AAs is comparable with that of ammonium (NH 4 + ), and (3) if atmospheric CO 2 concentration alters the aforementioned N cycling processes. A field experiment using universally labeled ammonium ( 15 NH 4 + ) and alanine ( 13 C 3 H 7 15 NO 2 ) demonstrated that 15 N is more readily taken up by plants and heterotrophic microorganisms as NH 4 + . Pine roots and microbes take up on average 2.4 and two times as much NH 4 + 15 N compared with alanine 15 N 1 week after tracer application. N cycling through soil pools was similar for alanine and NH 4 + , with the greatest 15 N tracer recovery in soil organic matter, followed by microbial biomass, dissolved organic N, extractable NH 4 + , and fine roots. Stoichiometric analyses of 13 C and 15 N uptake demonstrated that both plants and soil microorganisms take up alanine directly, with a 13 C :  15 N ratio of 3.3 : 1 in fine roots and 1.5 : 1 in microbial biomass. Our results suggest that intact AA (alanine) uptake contributes substantially to plant N uptake in loblolly pine forests. However, we found no evidence supporting increased recovery of free AAs in fine roots under elevated CO 2 , suggesting plants will need to acquire additional N via other mechanisms, such as increased root exploration or increased N use efficiency.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73167/1/j.1365-2486.2007.01411.x.pd

A Novel Role for Stat1 in Phagosome Acidification and Natural Host Resistance to Intracellular Infection by Leishmania major

Intracellular parasites of the genus Leishmania generate severe diseases in humans, which are associated with a failure of the infected host to induce a protective interferon γ (IFNγ)-mediated immune response. We tested the role of the JAK/STAT1 signaling pathway in Leishmania pathogenesis by utilizing knockout mice lacking the signal transducer and activator of transcription 1 (Stat1) and derived macrophages. Unexpectedly, infection of Stat1-deficient macrophages in vitro with promastigotes from Leishmania major and attenuated LPG1 knockout mutants (lpg−) specifically lacking lipophosphoglycan (LPG) resulted in a twofold increased intracellular growth, which was independent of IFNγ and associated with a substantial increase in phagosomal pH. Phagosomes in Stat1−/− macrophages showed normal maturation as judged by the accumulation of the lysosomal marker protein rab7, and provided normal vATPase activity, but were defective in the anion conductive pathway required for full vesicular acidification. Our results suggest a role of acidic pH in the control of intracellular Leishmania growth early during infection and identify for the first time an unexpected role of Stat1 in natural anti-microbial resistance independent from its function as IFNγ-induced signal transducer. This novel Stat1 function may have important implications to studies of other pathogens, as the acidic phagolysosomal pH plays an important role in antigen processing and the uncoating process of many viruses

New contiguity relation of the sixth Painlev\'e equation from a truncation

For the master Painlev\'e equation P6(u), we define a consistent method, adapted from the Weiss truncation for partial differential equations, which allows us to obtain the first degree birational transformation of Okamoto. Two new features are implemented to achieve this result. The first one is the homography between the derivative of the solution $u$ and a Riccati pseudopotential. The second one is an improvement of a conjecture by Fokas and Ablowitz on the structure of this birational transformation. We then build the contiguity relation of P6, which yields one new second order nonautonomous discrete equation.Comment: LaTex 2e. To appear, Physica

On the Schlesinger transformations of the sixth Painlev\'e equation

Following the recent discovery of two new Schlesinger transformations (ST) for the sixth Painlev\'e equation, we give the interrelations between all the known STs. We thus isolate the unique one which at the same time conserves the independent variable and is not a product of other STs.Comment: in French, LaTeX, 5 pages, to appear, Comptes rendus Acad. Sci. Pari

Disseminated Mycobacterium genavense Infection in Two Patients with AIDS

Mycobacterium genavense is a recently defined fastidious organism that has been identified as a cause of disseminated infection in patients with AIDS. We report the cases of two patients who had advanced AIDS and a clinical syndrome of fever, anorexia, abdominal pain, diarrhea, and weight loss. In addition, splenomegaly and lymphadenopathy were prominent in both cases, and in one patient's case radiographic findings were suggestive of splenic abscesses. Mycobacteria isolated from specimens of blood and bone marrow grew in liquid media but not on solid media. The results of DNA probe tests for Mycobacterium tuberculosis and Mycobacterium avium complex were false-positive for both patients. After treatment of the broth cultures to lyse red blood cells, the results of DNA probe tests were negative for these pathogens. Amplification and sequencing of 16S rRNA with use of the polymerase chain reaction indicated that the mycobacterial isolates from both patients had sequences identical to those previously reported for M. genavense. One patient survived 5 months after diagnosis, the other 2 months after diagnosis; only one patient responded (transiently) to antimycobacterial chemotherap

Surfaces de Bonnet et \'equations de Painlev\'e

Nous montrons que les \'equations du rep\`ere mobile des surfaces de Bonnet conduisent \`a une paire de Lax matricielle isomonodromique d'ordre deux pour la sixi\`eme \'equation de Painlev\'e. We show that the moving frame equations of Bonnet surfaces can be extrapolated to a second order, isomonodromic matrix Lax pair of the sixth Painlev\'e equation.Comment: in French. Formula (14) added. Two paragraphs added p 5-6. Old ref 1 removed, ref 7 added. To appear, Comptes rendus Acad. sciences Pari