Non-radial Oscillation Modes of Compact Stars with a Crust

Oscillation modes of isolated compact stars can, in principle, be a fingerprint of the equation of state (EoS) of dense matter. We study the non-radial high-frequency l=2 spheroidal modes of neutron stars and strange quark stars, adopting a two-component model (core and crust) for these two types of stars. Using perturbed fluid equations in the relativistic Cowling approximation, we explore the effect of a strangelet or hadronic crust on the oscillation modes of strange stars. The results differ from the case of neutron stars with a crust. In comparison to fluid-only configurations, we find that a solid crust on top of a neutron star increases the p-mode frequency slightly with little effect on the f-mode frequency, whereas for strange stars, a strangelet crust on top of a quark core significantly increases the f-mode frequency with little effect on the p-mode frequency.Comment: 10 pages, 6 figure

Analysis of the Effectiveness of the F-15E Risk Management During Peacetime Operations

Human factors are causal or contributory in 80% of Class A mishaps in the Air Force. Risk management tools are used throughout the service in every aircraft to help mitigate the risk of those human factors occurring. The F-15E Strike Eagle community was selected for analysis on the effectiveness of its risk management program but the data was comprised on Class A mishaps from Accident Investigation Boards since 2000 between the F-15 (all models), F-16 (all models), and F-22. Cases were selected if there were human factors root causes or contributory. A fault tree analysis coupled with the Department of Defense\u27s Human Factors Analysis and Classification System guidelines were used to determine the underlying factors which lead to a degradation in the aircrew\u27s ability to avoid catastrophes resulting in the loss of aircraft or life. These results were compared with existing risk management programs in the form of unit worksheet assessments. This study found all risk management programs within the F-15E community to be effective but inadequate for addressing the risk factors and a new assessment tool was developed to properly manage risk to aircrew. Finally, the F-15E training program was found to be contributory to managing risk to aircrew through its proficiency and currency annual program and requirements

Dissipative Dynamics of Collisionless Nonlinear Alfven Wave Trains

The nonlinear dynamics of collisionless Alfven trains, including resonant particle effects is studied using the kinetic nonlinear Schroedinger (KNLS) equation model. Numerical solutions of the KNLS reveal the dynamics of Alfven waves to be sensitive to the sense of polarization as well as the angle of propagation with respect to the ambient magnetic field. The combined effects of both wave nonlinearity and Landau damping result in the evolutionary formation of stationaryOA S- and arc-polarized directional and rotational discontinuities. These waveforms are freqently observed in the interplanetary plasma.Comment: REVTeX, 6 pages (including 5 figures). This and other papers may be found at http://sdphpd.ucsd.edu/~medvedev/papers.htm

Solitary lift : redesigning the base and tilter modules to meet customer needs

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 21).A theoretical investigation towards the redesign of the base and the tilting module of the Solitary Lift prototype improved the machine with a weight reduction of 5.731bs. Besides lighter weight, the other criteria used to measure improvement were speed, ease of use, and durability. In these areas this iteration of the prototype increased the speed to raise the tilter by 25 seconds, replaced a complicated locking mechanism with a familiar sleeve lock found on folding tables, and considered the substitution of plastic materials for aluminum in the structure.by Elliot B. Vasquez.S.B

Las Arterias Circunflejas Femorales en el Triángulo Femoral

Galdames, IS (Suazo Galdames, Ivan). Univ Talca, Fac Ciencias Salud, Talca, ChileIt is important to identify the origin and distribution of the circumflex femoral arteries (CFA) at the time of vascular reconstructive surgery. The femoral triangle contents in 92 lower extremities of formolized adult male cadavers of different ethnic groups, were dissected uncovering the femoral artery (FA) and its branches originating at the level of the femoral triangle. The origin of each CFA was identified determining the origin type and location. The medial circumflex femoral artery (MCFA) originated from the FA in 43 cases (46.7%); from the profunda femoris artery (PFA) in 41 cases (44.6%); from a common trunk formed by the PFA and CFA in 7 cases (7.6%), and in one case (1.1%) from the lateral circumflex femoral artery (LCFA). In 75 cases (81.5%) the MCFA was most proximal than the LCFA, and in 9 cases (9.8%) it originated at the same level. The LCFA originated at the PFA in 68 cases (73.9%); from the FA in 17 cases (18.5%); from a common trunk formed by the PFA and CFA in 7 cases (7.6%). The origin of the LCFA was considered regardless, whether the descending branch originated therein or from the FA. Considering the presence of a number of important elements it is essential to identify the precise origin of the arteries and its eventual variations in procedures carried out in that area

Características Estereológicas del Hígado de Rata (Rattus norvergicus) sometidas a Menopausia Inducida por Ovariectomía

Trujillo, E (reprint author), Univ Talca, Univ La Frontera, Lircay S-N, Talca, Chile.During menopause, hormonal changes such as decreased estradiol and increased follicle stimulating and luteinizing hormones occur. In premenopausal women fibrosis and hepatic steatosis is less than in postmenopausal women and improves when hormone replacement therapy is administered. The aim of this study was to determine quantitative aspects of the liver of rats undergoing an experimental model of ovariectomy-induced menopause. We used 10 Sprague-Dawley (Rattus norvergicus) healthy adults. The rats were weighed and divided into two groups (bilateral oophorectomy = Group Ovx and control = Group Sham). The animals were sacrificed at 60 days and the liver removed, obtaining a piece of each liver. Five cuts were made of 4 microns and stained with HE. We analyzed five fields per slide. M42 test was used. Stereo logical parameters considered were as follows: Nv, Vv, Sv and total number (Tn) of hepatocytes and sinusoids. The average weight of Ovx and Sham group was 300.8 g and 285.8 g, respectively. The Nv of hepatocytes of rats subjected to sham surgery (CS) and Ovx (CO) was 6.89 and 7.70 x 10(5)/mm(3) x 10(5)/mm(3), respectively. The Vv of CS and CO hepatocytes was 71.92% and 80.48%, respectively. SV and CO, CS hepatocytes was 260.61mm(2)/mm(3) and 273.64 mm(2)/mm(3), respectively. The average volume of CS livers was 8.40 mm(3) and hepatocyte Tn averaged 5.79 x 10(6). The average volume was 9.28 mm(3) CO livers and Tn of 7.15 x 10(6). Regarding the sinusoids, the Nv in the liver CS and CO was 2.81 x 10(5)/mm(3) and 2.64 x 10(5)/mm(3), respectively. The Vv of sinusoids in CS and CO was 16.74% and 16.46%, respectively. The sinusoids in rats Sv CS and CO was 49.40 mm(2)/mm(3) and 45.21 mm(2)/mm(3), respectively. The sinusoids Tn CS and CO averaged 2.37 x 10(6) and 2.45 x 10(6), respectively. The lack of estrogen can cause fibrosis and hepatic steatosis as noted by other authors, but also changes in the organization and the proportion of the components of the liver, factors to consider during diagnosis and prognosis of liver disorders

Insectos de la "una de gato" (Uncaria guianenesis y U. tomentosa : Rubiaceae), planta medical de la Amazonia peruana

Two species of #Rubiaceae$ known as "una de gato", vernaculate name, are medicinal plants very used in the Peruvian Amazonia. Its excessive exploitation in the natural environment has made its cultivation necessary. Different species of phytophagous insects have been observed on "una de gato" in an experimental plantation in Iquitos, Peru. (Résumé d'auteur

L'impact des prélèvements d'eau pour l'irrigation sur les régimes hydrologiques des sous-bassins du Tescou et de la Séoune (bassin Adour-Garonne, France)

Les besoins en eau pour l'irrigation des cultures des sous-bassins du Tescou et de la Séoune (Bassin Adour-Garonne) se sont considérablement accrus ces trente dernières années. Cela s'est manifesté, entre autres, par la création de très nombreuses retenues collinaires. Pour le sous-bassin du Tescou, aux crues rapides et peu volumineuses, on totalise 184 retenues individuelles dont le volume théorique cumulé s'élève à 4,3 Mm3 et qui interceptent environ un tiers (92 km2) de sa superficie (287 km2). Pour la Séoune, la pression due à l'usage de l'eau pour l'irrigation est un peu moins forte, compte tenu de sa taille (463 km2) et d'une ressource relativement abondante en hautes eaux. Près de 160 retenues collinaires sont dénombrées, elle représentent un volume de stockage théorique de 6,5 Mm3 pour une superficie interceptée d'environ un quart du sous-bassin (122 km2). Le suivi hydrométrique des sous-bassins permet de disposer pour chacun d'eux d'une chronique de débit influencée Q(t) sur une période d'observation d'environ 30 ans. A partir des débits observés, notre objectif a été d'identifier et de quantifier l'impact anthropique pour trois composantes du régime hydrologique : crue, module et étiage. L'approche saisonnière des crues et modules a permis une différenciation de l'impact anthropique selon les saisons "hiver" (mois 12 à 6) et "été" (mois 7 à 11). Cette saisonnalisation hydrologique reflète bien le mode de gestion actuel de la ressource en eau de ces sous-bassins agricoles : stockage l'hiver et irrigation à partir des retenues collinaires durant les premiers mois d'été. Pour identifier l'impact, nous avons fait usage de tests de détection de rupture de stationnarité des chroniques hydrologiques : de LANG (2004) pour les crues et d'une adaptation du test de BOIS (1986) pour les modules et étiages des sous-bassins. Pour ce qui concerne les crues d'été et les modules d'été les tests montrent que les chroniques sont stationnaires sur l'ensemble de la période d'observation. Pour les crues et les modules d'hiver par contre, les tests relèvent des ruptures de stationnarité des chroniques qui vont nous permettre de définir des sous-périodes stationnaires. Ces sous-périodes sont sensiblement cohérentes avec l'évolution des prélèvements théoriques cumulés de ces trente dernières années. L'analyse des ruptures de stationnarité menée sur les débits a été de même effectuée sur les pluies pour consolider nos résultats. La stationnarité des chroniques de pluie observées montre qu'il n'y a pas de composante climatique, autrement dit que la tendance détectée sur les débits est essentiellement d'origine anthropique. Il ne semble pas y avoir d'impact des éventuels pompages sur les débits d'étiage et tout particulièrement pour ce qui concerne la norme VCN30 "débit moyen minimum annuel sur 30 jours consécutifs" des deux sous-bassins. Finalement, l'usage de l'eau pour l'irrigation affecte essentiellement les crues et les modules de la saison hiver. Un essai de quantification de cette tendance a été menée à partir d'une analyse statistique associant les observations des sous-périodes stationnaires et les débits simulés pour une même référence pluviométrique. A partir des modélisations statistiques réalisées et des courbes de pression des besoins théoriques de l'irrigation, nous en avons déduit une tendance vraisemblable sur les quantiles de crue et les modules d'hiver. De manière générale, les crues de la saison hiver des deux sous-bassins sont fortement réduites en pointe et volume par l'ensemble des petites retenues. L'impact observé sur les quantiles de crue reste cohérent par rapport aux volumes théoriques prélevés dernièrement référencés. Les retenues collinaires sont sans action significative sur le temps de transfert (19j environ) du sous-bassin de la Séoune dont les crues sont volumineuses. Pour le Tescou par contre, aux crues rapides et peu volumineuses, le temps de transfert augmente sensiblement de 8h entre l'état de prélèvement zéro ("naturel" : 1,73j) et l'état actuel proche de 6 Mm3 (2,07j). Pour ce qui concerne les modules d'hiver des sous-bassins de la Séoune et du Tescou le coefficient d'écoulement moyen d'hiver diminue respectivement de 31% en moyenne et de 42% en moyenne entre l'état "naturel" et l'état anthropisé actuel. Cette diminution des coefficients d'écoulement est sans commune mesure avec les volumes théoriques stockés à partir des retenues collinaires. Autrement dit, les volumes théoriques des retenues collinaires ne peuvent expliquer à eux seuls la forte diminution des coefficients d'écoulement observés. Cependant, la cohérence des divers contrôles effectués, tant sur les chroniques observées que sur les modélisations effectuées, nous incitent à valider ces résultats. Ceux-ci devraient être retenus pour des objectifs de gestion immédiats ou ultérieurs de la ressource, si les conditions climatiques et d'occupation du sol n'évoluent guère.The water needs for farming irrigation in the Tescou and Séoune sub-basins (Basin Adour-Garonne) have increased considerably over the past thirty years. The needs were met, in part, by the creation of numerous reservoirs. For the Tescou catchment, with rapid but small-volume floods, we have 184 individual reservoirs with an accumulated theoretical volume of 4.3 Mm3, which intercept about a third (92 km2) of its surface (287 km2). For the Séoune catchment, the need for irrigation is a little less strong, considering its size (463 km2) and the presence of a relatively more abundant water resource. Close to 160 reservoirs can be counted, with a theoretical storage volume of 6.5 Mm3 for an intercepted surface of about a quarter of the sub-basin (122 km2). Hydrological monitoring data are available in the form of an influenced time series Q(t) with a period of observation of about 30 years for each sub-basin. From the observed discharges, our objective was to identify and to quantify anthropogenic impacts on three components of the hydrological regime: floods, annual mean discharge and low-flows. The seasonal approach of floods and annual mean discharges permitted a differentiation of the anthropogenic impact according to the "winter" (months 12 to 6) and "summer" (months 7 to 11) seasons. This approach reflects the present management of water in these agricultural sub-basins: storage in winter and irrigation during the first months of summer. To identify the impact, we used tests to detect stationnarity breaks in the time series: LANG (2004) for floods and an adaptation of BOIS (1986) for annual mean discharges and low-flows. For summer floods and summer annual mean discharges, the tests showed that the time series were stationary during the period of observation. For winter floods and winter annual mean discharges the tests showed stationnarity breaks in the time series, which allowed us to define the stationary sub-periods. These sub-periods were consistent with the evolution of the accumulated theoretical withdrawals during the last thirty years. The same analysis of stationnarity breaks made on flows was also done on rainfall to strengthen our results. The stationnarity of the rainfall observed over the time series shows that there is not a climatic component; in other words, the trends detected in the streamflow record are essentially of anthropogenic origin. For both sub-basins, the BOIS statistical test did not reveal any impact of possible pumping on the low-flows, and especially for the VCN30 norm (minimum annual mean flow over a period of 30 consecutive days).Finally, the use of water for irrigation essentially affects winter floods and annual mean discharges. A test to quantify this trend was carried out with a statistical analysis associating the observations of each stationary sub-period and the discharges simulated for a similar rainfall. From the resulting statistical models and the curves of pressure of theoretical irrigation requirements, we deduced a probable trend for the quantiles of winter floods and mean annual winter discharges. In a general way, winter floods in both sub-basins were strongly reduced in peak and volume by the set of the small reservoirs. The impact observed on the flood quantiles remains coherent in relation to the theoretical withdrawal volumes referenced above. The reservoirs are without significant action on the transfer time (approximately 19 days) in the Séoune sub-basin, where the floods are voluminous. On the other hand, for the Tescou sub-basin, with rapid and small-volume floods, the time of transfer increases considerably (8 h) between the state of zero withdrawal (natural: 1.73 days) and the present state close to 6 Mm3 (2.07 days). Concerning winter annual mean discharge in both sub-basins, the winter mean runoff coefficient decreased 31% and 42%, for the Séoune and Tescou sub-basins respectively, between the natural state and the present state. This reduction of the runoff coefficients does not correspond to the theoretical volumes stocked in the reservoirs. In other words, the theoretical volumes of the reservoirs cannot completely explain the observed strong reduction of the runoff coefficients. However, the consistency of the various controls, both on the observed time series and the modelled results, lend credibility to the overall results. These results should be taken into consideration in water management, if the climatic conditions and soil occupation don't change