Hermitian Young Operators

Starting from conventional Young operators we construct Hermitian operators which project orthogonally onto irreducible representations of the (special) unitary group.Comment: 15 page

Two Examples of Circular Motion for Introductory Courses in Relativity

The circular twin paradox and Thomas Precession are presented in a way that makes both accessible to students in introductory relativity courses. Both are discussed by examining what happens during travel around a polygon and then in the limit as the polygon tends to a circle. Since relativistic predictions based on these examples can be verified in experiments with macroscopic objects such as atomic clocks and the gyroscopes on Gravity Probe B, they are particularly convincing to introductory students.Comment: Accepted by the American Journal of Physics This version includes revision

Rheological Properties of Mudflows Associated with the May 1980 Eruptions of Mount St. Helens Volcano, Washington

Rheological properties of three recent mudflows at Mount St. Helens were estimated using techniques developed for determining the properties of debris flows based on the geometry of their deposits. Calculated yield strengths of 1100, 1000, and 400 Pa, maximum flow velocities of 10 to 31 m/s, volumetric flow rates of 300 to 3400 m3/s, and plastic viscosities of 20 to 320 Pa-s all compare favorably with measured and estimated values cited in the literature. A method for determining likely sites of future mudflow initiation based on these data is outlined

HIPASS Detection of an Intergalactic Gas Cloud in the NGC 2442 Group

We report the discovery, from the HI Parkes All-Sky Survey (HIPASS), of a gas cloud associated with the asymmetric spiral galaxy NGC 2442. This object, designated HIPASS J0731-69, contains ~10^9 M_sun of HI, or nearly one-third as much atomic gas as NGC 2442 itself. No optical counterpart to any part of HIPASS J0731-69 has yet been identified, consistent with the gas being diffuse, and with its stream-like kinematics. If the gas in HIPASS J0731-69 was once part of NGC 2442, then it was most likely a fairly recent tidal encounter with a moderately massive companion which tore it loose, although the possibility of ram-pressure stripping cannot be ruled out. This discovery highlights the potential of the HIPASS data for yielding new clues to the nature of some of the best-known galaxies in the local universe.Comment: 8 pages, 4 figures, uses "emulateapj5.sty". Accepted for publication in ApJ, Vol. 555, 1 July 2001. Figs 1 and 2 included as JPE

More evidence for hidden spiral and bar features in bright early-type dwarf galaxies

Following the discovery of spiral structure in IC3328 (Jerjen et al.~2000), we present further evidence that a sizable fraction of bright early-type dwarfs in the Virgo cluster are genuine disk galaxies, or are hosting a disk component. Among a sample of 23 nucleated dwarf ellipticals and dS0s observed with the Very Large Telescope in $B$ and $R$, we found another four systems exhibiting non-axisymmetric structures, such as a bar and/or spiral arms, indicative of a disk (IC0783, IC3349, NGC4431, IC3468). Particularly remarkable are the two-armed spiral pattern in IC0783 and the bar and trailing arms in NGC4431. For both galaxies the disk nature has recently been confirmed by a rotation velocity measurement (Simien & Prugniel 2002). Our photometric search is based on a Fourier decomposition method and a specific version of unsharp masking. Some ``early-type'' dwarfs in the Virgo cluster seem to be former late-type galaxies which were transformed to early-type morphology, e.g. by ``harassment'', during their infall to the cluster, while maintaining part of their disk structure.Comment: A&A accepte

The stellar dynamics and mass of NGC 1316 using the radial velocities of planetary nebulae

We present a study of the kinematics of the outer regions of the early-type galaxy NGC 1316, based on radial velocity measurements of 43 planetary nebulae as well as deep integrated-light absorption line spectra. The smoothed velocity field of NGC 1316 indicates fast rotation at a distance of 16 kpc, possibly associated with an elongated feature orthogonal to the inner dust lanes. The mean square stellar velocity is approximately independent of radius, and the estimated total mass of the system is 2.6 x 10^11 M_sun within a radius of 16 kpc, implying an integrated mass-to-light ratio of M/L_B = 8.Comment: 39 pages, 14 figures, in press on The Astrophysical Journal n. 50

Cost-Effectiveness of Primary versus Secondary Prophylaxis with Pegfilgrastim in Women with Early-Stage Breast Cancer Receiving Chemotherapy

AbstractObjectiveProphylaxis with granulocyte colony-stimulating factor (G-CSF) reduces the risk of febrile neutropenia (FN) in patients receiving myelosuppressive chemotherapy. We estimated the incremental cost-effectiveness of G-CSF pegfilgrastim primary (starting in cycle 1 and continuing in subsequent cycles of chemotherapy) versus secondary (only after an FN event) prophylaxis in women with early-stage breast cancer receiving myelosuppressive chemotherapy with a ≥20% FN risk.MethodsA decision-analytic model was constructed from a health insurer's perspective with a lifetime study horizon. The model considers direct medical costs and outcomes related to reduced FN and potential survival benefits because of reduced FN-related mortality. Inputs for the model were obtained from the medical literature. Sensitivity analyses were conducted across plausible ranges in parameter values.ResultsThe incremental cost-effectiveness ratio (ICER) of pegfilgrastim as primary versus secondary prophylaxis was $48,000/FN episode avoided. Adding survival benefit from avoiding FN mortality yielded an ICER of$110,000/life-year gained (LYG) or $116,000/quality-adjusted life-year (QALY) gained. The most influential factors included FN case-fatality, FN relative risk reduction from primary prophylaxis, and age at diagnosis.ConclusionsCompared with secondary prophylaxis, the cost-effectiveness of pegfilgrastim as primary prophylaxis may be equivalent or superior to other commonly used supportive care interventions for women with breast cancer. Further assessment of the direct impact of G-CSF on short- and long-term survival is needed to substantiate these findings

Psychoative herbs commercialized in streets of Diadema (SP, Brazil): risk in its consumption

O comércio popular de drogas vegetais sem a garantia da qualidade implica em risco sanitário. O presente estudo fez uma análise interdisciplinar da rede de comércio de drogas vegetais (DVs) com foco nas drogas vegetais psicoativas (DVPs), disponíveis no comércio popular da Cidade de Diadema, e os riscos associados ao seu consumo. Métodos da etnofarmacologia, tais como: entrevistas informais, semi-estruturadas e observação participante foram utilizados para a realização do trabalho de campo; durante o qual, selecionaram-se quatro comerciantes, a fim de registrar a obtenção, manipulação, acondicionamento e tipos de DVs comercializadas. Foram registradas 63 DVs que remetiam a atividade psicoativa (DVPs) e, categorizadas em estimulantes (67%), depressoras (27%), depressoras e estimulantes (1%) e finalmente algumas não puderam ser definidas (5%). Essas DVPs tiveram seus nomes populares, forma de preparo e uso, partes utilizadas, contraindicações e doses registradas. Dezoito das 63 DVPs foram selecionadas segundo critérios do estudo, e seus lotes foram adquiridos dos entrevistados, a fim de serem analisados pela microbiologia (61 lotes) e farmacognosia (somente 22 daqueles, referentes a apenas 8 DVPs). Os resultados obtidos por essas áreas, somados a consultas em literaturas científicas, acerca de descrições de reações adversas, serviram de subsídio para a análise final dessas DVPs no contexto da farmacovigilância. Observaram-se deficiências principalmente na manipulação e acondicionamento das DVs por parte dos comerciantes, favorecendo sua contaminação e degradação. Os resultados das análises microbiológicas detectaram que 16% das DVPs analisadas apresentaram populações de bactérias (aeróbias e enterobactérias) superiores a 105 UFC/g e 31%, populações de fungos (bolores e leveduras) superiores a 103 UFC/g e a presença de espécies microbianas indicadoras de risco em 17 DVPs, especificamente em 74% dos 61 lotes, além de fungos produtores de aflatoxinas B1 e/ou B2 em quatro deles. Os resultados da farmacognosia demonstraram que 73% dos lotes foram reprovados ao menos em um dos demais parâmetros analisados (presença de contaminantes, caracterização e perfil cromatográfico). Sendo que, 50% dos 22 lotes analisados não coincidem com as especificações da farmacopéia e 36% apresentaram contaminação por outros órgãos vegetais, superior ao permitido nas monografias e um lote apresentou contaminação por insetos. Todos os 22 lotes foram reprovados na avaliação do rótulo (nomenclatura e validade) e praticamente todas as embalagens foram consideradas inadequadas. Além dos dados obtidos nessas análises, descrições de contra-indicações, efeitos adversos e interações medicamentosas foram encontradas na literatura científica para as 3 DVPs que tiveram sua identidade confirmada pela farmacognosia (camomila, ginkgo biloba e guaraná). Os resultados obtidos nesse estudo possibilitam observar as prioridades de adequação sanitária do comércio popular de DVs, bem como, traçar um perfil da qualidade das DVPs comercializadas segundo os parâmetros analisados. Conclui-se que essas DVPs reúnem importantes fatores capazes de causar danos à saúde dos consumidores, especialmente para alguns grupos como gestantes e indivíduos imunossuprimidos.The popular trade of herbal drugs without quality assurance implies a health risk. This study was an interdisciplinary analysis of the herbal drugs (DVs) trade network with focus on psychoactive drug plant (DVPs) available on the Brazilian city of Diadema, and risks associated with its consumption. Methods of ethnopharmacology, such as informal interviews, semi-structured interviews and participant observation were used for the completion of the fieldwork, during which four tradesmen were selected to register the collection, handling, packaging and types of DVs marketed. We registered 63 DVs that referred to psychoactive activity (DVPs) and categorized as stimulants (67%), depressants (27%), depressants and stimulants (1%) and finally some could not be set (5%). These DVPs had their popular names, preparations and uses, used parts, contraindications, and doses recorded. Eighteen of the 63 DVPs were selected according to the study criteria, and their lots were purchased by the selected tradesmen to be examined by microbiology (61 lots) and Pharmacognosy (only 22 of those lots, related to only 8 DVPs). The results for these areas, together with query in the scientific literature concerning descriptions of adverse reactions, provided the grant for the final analysis of these DVPs in the context of pharmacovigilance. Deficiencies were observed mainly in the handling and packaging of DVs by the traders, favoring its contamination and degradation. The microbiological analysis found that 16% of DVPs analyzed showed populations of bacteria (aerobic and Enterobacteriaceae) exceeding 105 CFU/g and 31%, populations of fungi (molds and yeasts) exceeding 103 CFU/g and the presence of risk indicator microbial species in 17 DVPs, specifically in 74% of the 61 lots, in addition to aflatoxin B1 or B2 producing fungi in four of them. The results of pharmacognosy showed that 73% had failed at least one of the parameters (contaminants, characterization and chromatographic profile), 50% of the 22 lots analyzed did not match the specifications of the pharmacopoeia, 36% were contaminated by other plant organs than those permitted in the monographs and a lot contamination by insects was found. All 22 lots have been disapproved in the evaluation of the label (classification and validity) and virtually all packages were considered inadequate. In addition to data obtained from such analysis, descriptions of contraindications, adverse effects and drug interactions were found in the literature for 3 DVPs who had their identity confirmed by the Pharmacognosy (chamomile, ginkgo biloba and guarana). The results obtained here allow us to observe the priorities of sanitary adequacy of the DVs popular trade, as well as establishing a profile of quality of DVPs marketed according to the analyzed parameters. We conclude that these DVPs gather important factors that could cause damage to the consumers health, especially for some groups such as pregnant women and immunosuppressed individuals.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)TEDEBV UNIFESP: Teses e dissertaçõe

The disruption of nearby galaxies by the Milky Way

Interactions between galaxies are common and are an important factor in determining their physical properties such as position along the Hubble sequence and star-formation rate. There are many possible galaxy interaction mechanisms, including merging, ram-pressure stripping, gas compression, gravitational interaction and cluster tides. The relative importance of these mechanisms is often not clear, as their strength depends on poorly known parameters such as the density, extent and nature of the massive dark halos that surround galaxies. A nearby example of a galaxy interaction where the mechanism is controversial is that between our own Galaxy and two of its neighbours -- the Large and Small Magellanic Clouds. Here we present the first results of a new HI survey which provides a spectacular view of this interaction. In addition to the previously known Magellanic Stream, which trails 100 degrees behind the Clouds, the new data reveal a counter-stream which lies in the opposite direction and leads the motion of the Clouds. This result supports the gravitational model in which leading and trailing streams are tidally torn from the body of the Magellanic Clouds.Comment: 17 pages with 5 figures in gif format, scheduled for publication in the August 20th, 1998 issue of Natur

Integrated Results from Analysis of the Rocknest Aeolian Deposit by the Curiosity Rover

The Mars Science Laboratory Curiosity rover spent 45 sols (from sol 56-101) at an area called Rocknest (Fig. 1), characterizing local geology and ingesting its aeolian fines into the analytical instruments CheMin and SAM for mineralogical and chemical analysis. Many abstracts at this meeting present the contextual information and detailed data on these first solid samples analyzed in detail by Curiosity at Rocknest. Here, we present an integrated view of the results from Rocknest - the general agreement from discussions among the entire MSL Science Team