859 resultados para Leaf orientation
Resumo:
We describe simulations of an elastic filament immersed in a fluid and subjected to a body force. The coupling between the fluid flow and the friction that the filament experiences induces bending and alignment perpendicular to the force. With increasing force there are four shape regimes, ranging from slight distortion to an unsteady tumbling motion. We also find marginally stable structures. The instability of these shapes and the alignment are explained by induced bending and nonlocal hydrodynamic interactions. These effects are experimentally relevant for stiff microfilaments.
Resumo:
Le suicide et les tentatives de suicide des adolescents sont des enjeux de santé publique majeurs. En s'appuyant sur le modèle de soins développé à Genève, nous décrivons les différents temps nécessaires pour accueillir, évaluer et orienter un adolescent pris dans un mouvement suicidaire. Un temps d'accueil et d'évaluation pédiatrique, puis un temps d'évaluation psychiatrique et enfin un temps d'orientation à l'issue duquel est proposée une prise en charge spécifique. En fonction des caractéristiques cliniques du jeune (impulsivité, symptomatologie anxio-dépressive...), de sa capacité d'engagement dans les soins et de la qualité des liens du réseau, la prise en charge sera soit ambulatoire intensive, soit hospitalière. Suicide and suicide attempts of adolescents are major public health issues. Based on a model of care developed in Geneva, we describe the conditions necessary to evaluate and guide a teenager trapped in a suicidal behavior. First of all, there must be some time dedicated to pediatric assessement followed by a psychiatric evaluation and finally, the adolescent can be oriented toward specific treatment. Depending on the clinical characteristics of the young adolescent and according to his willingness to engage himself in intensive follow-up (impulsivity, anxious?--depressive symptomatology...), cares will be given either as outpatient with close monitoring or inpatient.
Resumo:
The use of leaf total nitrogen concentration as an indicator for nutritional diagnosis has some limitations. The objective of this study was to determine the reliability of total N concentration as an indicator of N status for eucalyptus clones, and to compare it with alternative indicators. A greenhouse experiment was carried out in a randomized complete block design in a 2 × 6 factorial arrangement with plantlets of two eucalyptus clones (140 days old) and six levels of N in the nutrient solution. In addition, a field experiment was carried out in a completely randomized design in a 2 × 2 × 2 × 3 factorial arrangement, consisting of two seasons, two regions, two young clones (approximately two years old), and three positions of crown leaf sampling. The field areas (regions) had contrasting soil physical and chemical properties, and their soil contents for total N, NH+4-N, and NO−3-N were determined in five soil layers, up to a depth of 1.0 m. We evaluated the following indicators of plant N status in roots and leaves: contents of total N, NH+4-N, NO−3-N, and chlorophyll; N/P ratio; and chlorophyll meter readings on the leaves. Ammonium (root) and NO−3-N (root and leaf) efficiently predicted N requirements for eucalyptus plantlets in the greenhouse. Similarly, leaf N/P, chlorophyll values, and chlorophyll meter readings provided good results in the greenhouse. However, leaf N/P did not reflect the soil N status, and the use of the chlorophyll meter could not be generalized for different genotypes. Leaf total N concentration is not an ideal indicator, but it and the chlorophyll levels best represent the soil N status for young eucalyptus clones under field conditions.
Resumo:
Taphrina deformans is a fungus responsible for peach leaf curl, an important plant disease. It is phylogenetically assigned to the Taphrinomycotina subphylum, which includes the fission yeast and the mammalian pathogens of the genus Pneumocystis. We describe here the genome of T. deformans in the light of its dual plant-saprophytic/plant-parasitic lifestyle. The 13.3-Mb genome contains few identifiable repeated elements (ca. 1.5%) and a relatively high GC content (49.5%). A total of 5,735 protein-coding genes were identified, among which 83% share similarities with other fungi. Adaptation to the plant host seems reflected in the genome, since the genome carries genes involved in plant cell wall degradation (e.g., cellulases and cutinases), secondary metabolism, the hallmark glyoxylate cycle, detoxification, and sterol biosynthesis, as well as genes involved in the biosynthesis of plant hormones. Genes involved in lipid metabolism may play a role in its virulence. Several locus candidates for putative MAT cassettes and sex-related genes akin to those of Schizosaccharomyces pombe were identified. A mating-type-switching mechanism similar to that found in ascomycetous yeasts could be in effect. Taken together, the findings are consistent with the alternate saprophytic and parasitic-pathogenic lifestyles of T. deformans. IMPORTANCE: Peach leaf curl is an important plant disease which causes significant losses of fruit production. We report here the genome sequence of the causative agent of the disease, the fungus Taphrina deformans. The genome carries characteristic genes that are important for the plant infection process. These include (i) proteases that allow degradation of the plant tissues; (ii) secondary metabolites which are products favoring interaction of the fungus with the environment, including the host; (iii) hormones that are responsible for the symptom of severely distorted leaves on the host; and (iv) drug detoxification enzymes that confer resistance to fungicides. The availability of the genome allows the design of new drug targets as well as the elaboration of specific management strategies to fight the disease.
Resumo:
The particle orientation in several Y-Fe2O3magnetic tapes has been quantitatively evaluated by using the data of both Mössbauer and hysteresis loop measurements performed in the three orthogonal directions. A texture function has been obtained as a development of real harmonics. The profile of the texture function gives the quality of the different magnetic tapes. A different degree of particle orientation at the surface of the tape is evidenced by means of conversion electron Mössbauer spectra.
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Another recently enacted law is the Iowa Safe Schools Law. Effective September 1, 2007, Iowa Code Chapter 280 requires both public and private schools to establish policies prohibiting harassment and bullying against students by employees, school volunteers, or other students. Sexual Orientation and Gender identity are covered under the Safe Schools Law. Students may now seek remedies under both Chapter 216 and Chapter 280.
Resumo:
Effective July 1, 2007, the Iowa Civil Rights Act (Iowa Code Chapter 216) was expanded to add sexual orientation and gender identity to the list of protected characteristics. It is now illegal in Iowa to discriminate against a person because of his/her actual or perceived sexual orientation or gender identity.
Resumo:
Effective July 1, 2007, the Iowa Civil Rights Act (Iowa Code Chapter 216) was expanded to add sexual orientation and gender identity to the list of protected classes. It is now ILLEGAL in Iowa to discriminate against a person because of his/her sexual orientation or gender identity.
Resumo:
Effective July 1, 2007, the Iowa Civil Rights Act (Iowa Code Chapter 216) was expanded to add sexual orientation and gender identity to the list of protected classes. It is now ILLEGAL in Iowa to discriminate against a person because of his/her sexual orientation or gender identity.
Resumo:
To study the stress-induced effects caused by wounding under a new perspective, a metabolomic strategy based on HPLC-MS has been devised for the model plant Arabidopsis thaliana. To detect induced metabolites and precisely localise these compounds among the numerous constitutive metabolites, HPLC-MS analyses were performed in a two-step strategy. In a first step, rapid direct TOF-MS measurements of the crude leaf extract were performed with a ballistic gradient on a short LC-column. The HPLC-MS data were investigated by multivariate analysis as total mass spectra (TMS). Principal components analysis (PCA) and hierarchical cluster analysis (HCA) on principal coordinates were combined for data treatment. PCA and HCA demonstrated a clear clustering of plant specimens selecting the highest discriminating ions given by the complete data analysis, leading to the specific detection of discrete-induced ions (m/z values). Furthermore, pool constitution with plants of homogeneous behaviour was achieved for confirmatory analysis. In this second step, long high-resolution LC profilings on an UPLC-TOF-MS system were used on pooled samples. This allowed to precisely localise the putative biological marker induced by wounding and by specific extraction of accurate m/z values detected in the screening procedure with the TMS spectra.
Resumo:
L'introduction au numéro thématique de L'OSP sur la Suisse décrit quelques particularités institutionnelles, politiques et socioéconomiques de ce pays, afin de situer les différentes contributions. Elle expose également les logiques retenues pour le choix des contributions.