Recherche et caractérisation de sols résistants aux Pythium spp. en Amazonie brésilienne

Aux environs de la ville de Manaus (Amazonie brésilienne), les sols sont localisés dans deux écosystèmes: ‘terra firme’ recouverte de foret vierge ou cultivée et ‘varzea’, zones submergées chaque année et cultivées. 160 échantillons de sol ont été prélevés dans ccs deux zones, puis analysés afin de déterminer leur capacité de fonte des semis, causée par les Pythium spp.; 76 de ces sols semblaient non infestés, ou ne l'étaient que faiblement. Afin de déterminer leur réceptivité vis‐à‐vis des Pythium spp., les 76 sols ont été inoculés avec 10% d'un sol infesté naturellement, et la capacité d'infection a étéévaluée aprés des incubations de 4, 8, 12 et 16 semaines par tests biologiques sur jeunes plants de concombre. L'aptitude à supprimer les Pythium spp. n'est apparue que dans les écosystèmes ‘terra firme'et non dans les ‘varzeas’ submergés. La fréquence des sols pouvant supprimer la maladie semblait décroitre en fonction de la mise en culture: 82% dans les sols de foret vierge; 67% dans les sols de pépinières forestiéres; 53% dans les forets gérées; 31% dans les sols forestiers mis en culture avec des cultures variées; 7% dans les sols forestiers mis en culture et portant des cultures maraichères. On a constaté trois types d'aptitude à supprimer les Pythium spp. aprés inoculation des sols: (1) résistance apparaissant rapidement et se maintenant à un niveau élevé et constant (jusqu'à 16 semaines); (2) résistance initiate élevée, mais non durable; (3) résistance initialement faible, mais croissante avec le temps. Une partie de cette dynamique semble etre sous controle microbien. Le développement agricole autour de Manaus ainsi que les systèmes de culture intensifs peuvent rapidement modifier les écosystèmes microbiens des sols et nuire à leur capacité naturelle à supprimer les Pythium spp. Copyright © 1987, Wiley Blackwell. All rights reserve

Morphology of the megalopa of the mud crab, Rhithropanopeus harrisii (Gould, 1841) (Decapoda, Brachyura, Panopeidae), identified by DNA barcode.

The morphology of the megalopa stage of the panopeid Rhithropanopeus harrisii is redescribed and illustrated in detail from plankton specimens identified by DNA barcode (16S mtDNA) as previous descriptions do not meet the current standard of brachyuran larval description. Several morphological characters vary widely from those of other panopeid species which could cast some doubt on the species’ placement in the same family. Besides, some anomalous megalopae of R. harrisii were found among specimens reared at the laboratory from zoeae collected in the plankton. These anomalous morphological features are discussed in terms of problems associated with laboratory rearing conditions

Classical Coulomb three-body problem in collinear eZe configuration

Classical dynamics of two-electron atom and ions H$^{-}$, He, Li$^{+}$, Be$^{2+}$,... in collinear eZe configuration is investigated. It is revealed that the mass ratio $\xi$ between necleus and electron plays an important role for dynamical behaviour of these systems. With the aid of analytical tool and numeircal computation, it is shown that thanks to large mass ratio $\xi$, classical dynamics of these systems is fully chaotic, probably hyperbolic. Experimental manifestation of this finding is also proposed.Comment: Largely rewritten. 21 pages. All figures are available in http://ace.phys.h.kyoto-u.ac.jp/~sano/3-body/index.htm

Existence and Stability of Symmetric Periodic Simultaneous Binary Collision Orbits in the Planar Pairwise Symmetric Four-Body Problem

We extend our previous analytic existence of a symmetric periodic simultaneous binary collision orbit in a regularized fully symmetric equal mass four-body problem to the analytic existence of a symmetric periodic simultaneous binary collision orbit in a regularized planar pairwise symmetric equal mass four-body problem. We then use a continuation method to numerically find symmetric periodic simultaneous binary collision orbits in a regularized planar pairwise symmetric 1, m, 1, m four-body problem for $m$ between 0 and 1. Numerical estimates of the the characteristic multipliers show that these periodic orbits are linearly stability when $0.54\leq m\leq 1$, and are linearly unstable when $0<m\leq0.53$.Comment: 6 figure

Developing a Cancer Survivorship Curriculum for Family Medicine Residents: A Needs Assessment

With the increasing survival of cancer patients, primary care residents must be familiar with the late effects of cancer treatment and be able to offer appropriate survivorship care in partnership with cancer care specialists. To address these paired public health and educational needs, an interdisciplinary group at our institution is developing, implementing, and evaluating an online cancer survivorship curriculum for primary care residents. In the development phase of our survivorship curriculum we administered an online needs assessment survey questionnaire and conducted a focus group interview with the family medicine residents at our institution. Residents indicated that they rarely utilized survivorship care plans or explicitly negotiated a program of shared patient care with the patient’s cancer specialists. Less than satisfactory elements of cancer survivorship education were identified. Cancer survivorship care is common in family medicine residency care and opportunities exist to improve education, care, and collaboration

Resistance to local anesthesia in people with the Ehlers-Danlos Syndromes presenting for dental surgery

Background: People with the Ehlers-Danlos Syndromes (EDS), a group of heritable disorders of connective tissue, often report experiencing dental procedure pain despite local anesthetic (LA) use. Clinicians have been uncertain how to interpret this apparent LA resistance, as comparison of EDS and non-EDS patient experience is limited to anecdotal evidence and small case series. The primary goal of this hypothesis-generating study was to investigate the recalled adequacy of pain prevention with LA administered during dental procedures in a large cohort of people with and without EDS. A secondary exploratory aim asked people with EDS to recall comparative LA experiences. Methods: We administered an online survey through various social media platforms to people with EDS and their friends without EDS, asking about past dental procedures, LA exposures, and the adequacy of procedure pain prevention. Among EDS respondents who both received LA and recalled the specific LA used, we compared agent-specific pain prevention for lidocaine, procaine, bupivacaine, mepivacaine, and articaine. Results: Among the 980 EDS respondents who had undergone a dental procedure LA, 88% (n = 860) recalled inadequate pain prevention. Among 249 non EDS respondents only 33% (n = 83) recalled inadequate pain prevention (P < 0.001 compared to EDS respondents). The agent with the highest EDS-respondent reported success rate was articaine (30%), followed by bupivacaine (25%), and mepivacaine (22%). Conclusions: EDS survey respondents reported nearly three times the rate of LA non-response compared to non-EDS respondents, suggesting that LAs were less effective in preventing their pain associated with routine office dental procedures

Enforced Expression of the Transcriptional Coactivator OBF1 Impairs B Cell Differentiation at the Earliest Stage of Development

OBF1, also known as Bob.1 or OCA-B, is a B lymphocyte-specific transcription factor which coactivates Oct1 and Oct2 on B cell specific promoters. So far, the function of OBF1 has been mainly identified in late stage B cell populations. The central defect of OBF1 deficient mice is a severely reduced immune response to T cell-dependent antigens and a lack of germinal center formation in the spleen. Relatively little is known about a potential function of OBF1 in developing B cells. Here we have generated transgenic mice overexpressing OBF1 in B cells under the control of the immunoglobulin heavy chain promoter and enhancer. Surprisingly, these mice have greatly reduced numbers of follicular B cells in the periphery and have a compromised immune response. Furthermore, B cell differentiation is impaired at an early stage in the bone marrow: a first block is observed during B cell commitment and a second differentiation block is seen at the large preB2 cell stage. The cells that succeed to escape the block and to differentiate into mature B cells have post-translationally downregulated the expression of transgene, indicating that expression of OBF1 beyond the normal level early in B cell development is deleterious. Transcriptome analysis identified genes deregulated in these mice and Id2 and Id3, two known negative regulators of B cell differentiation, were found to be upregulated in the EPLM and preB cells of the transgenic mice. Furthermore, the Id2 and Id3 promoters contain octamer-like sites, to which OBF1 can bind. These results provide evidence that tight regulation of OBF1 expression in early B cells is essential to allow efficient B lymphocyte differentiation

Arterial Elasticity in Ehlers-Danlos Syndromes

Ehlers-Danlos Syndromes (EDS) are a group of heritable disorders of connective tissue (HDCT) characterized by joint hypermobility, skin hyperextensibility, and tissue fragility. Orthostatic intolerance (OI) is highly prevalent in EDS however mechanisms linking OI to EDS remain poorly understood. We hypothesize that impaired blood pressure (BP) and heart rate control is associated with lower arterial stiffness in people with EDS. Orthostatic vital signs and arterial stiffness were assessed in a cohort of 60 people with EDS (49 female, 36 ± 16 years). Arterial elasticity was assessed by central and peripheral pulse wave velocity (PWV). Central PWV was lower in people with EDS compared to reference values in healthy subjects. In participants with EDS, central PWV was correlated to supine systolic BP (r = 0.387, p = 0.002), supine diastolic BP (r = 0.400, p = 0.002), and seated systolic BP (r = 0.399, p = 0.002). There were no significant correlations between PWV and changes in BP or heart rate with standing (p > 0.05). Between EDS types, there were no differences in supine hemodynamics or PWV measures (p > 0.05). These data demonstrate that increased arterial elasticity is associated with lower BP in people with EDS which may contribute to orthostatic symptoms and potentially provides a quantitative clinical measure for future genotype-phenotype investigations