55 research outputs found

    Observations of a Protistan Disease Similar to QPX in Mercenaria mercenaria (Hard Clams) from the Coast of Massachusetts

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    During the summer and fall of 1995, in clam aquaculture leases at two locations on the coast of Massachusetts, significant mortalities were observed to occur primarily in 112 role= presentation style= font-size: 0.9px; display: inline-block; position: relative; \u3e- to 2-year old hard clams (Mercenaria mercenaria,quahog) planted in the leases. Examination of hard clams from those leases suggested a parasite similar to QPX (Quahog Parasite Unknown), as described by Whyte, S. K., Cawthorn, R. J., and McGladdery, S. E. (1994,Can. Dis. Ag. Org.19, 129–136), was responsible for the poor condition of affected clams and the resulting high mortality. In clam tissues, the QPX-like parasite formed thalli surrounded by a mucofilamentous net. Larger thalli underwent endosporulation producing sporangia that contained approximately 40 endospores. Rupture of the sporangium released the endospores into the surrounding tissue. Inflammatory response by the clam to infection was chronic, active, and granulomatous. The occurrence both of phagocytic multinucleated giant inflammatory cells and inflammatory encapsulation of parasites were commonly identified as part of the response. Moderately to severely infected clams showed significantly reduced growth and a poorer condition index as compared to uninfected or mildly infected clams

    A closer look at the uncertainty relation of position and momentum

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    We consider particles prepared by the von Neumann-L\"uders projection. For those particles the standard deviation of the momentum is discussed. We show that infinite standard deviations are not exceptions but rather typical. A necessary and sufficient condition for finite standard deviations is given. Finally, a new uncertainty relation is derived and it is shown that the latter cannot be improved.Comment: 3 pages, introduction shortened, content unchange

    In vivo evaluation of Aloysia triphylla britton (lemon verbena) essential oil toxicity and citral anti-Trypanosma cruzi activity.

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    Introducción: Existe escasa investigación en enfermedades olvidadas. Las plantas medicinales son una potencial fuente de compuestos antimicrobianos. Objetivos: Determinar la toxicidad del aceite esencial de Aloysia triphylla y la actividad del citral contra Trypanosoma cruzi en ratones. Diseño: Estudio experimental preclínico in vivo. Institución: Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Perú. Material: Ratones albinos. Intervenciones: La toxicidad aguda oral a dosis única fue evaluada en ratas albinas. Para la actividad tripanocida se utilizaron ratones asignados a los siguientes grupos: infectados y no tratados (G1), infectados y tratados con citral en dosis de 50, 150 y 300 mg/kg/día (G2, G3 y G4, respectivamente), infectados y tratados con benznidazol 100 mg/kg (G5) y no infectados y no tratados (G6). La parasitemia fue determinada individualmente cada 2 días por microscopia directa. En los días 14, 21 y 28 post infección, cinco ratones de cada grupo fueron sacrificados y los corazones procesados para análisis histopatológico. Principales medidas de resultados: Signos de toxicidad y mortalidad, y parasitemia. Resultados: La dosis límite de 2 000 mg/kg no provocó signos ni síntomas de toxicidad y los estudios anatomopatológicos macroscópicos y microscópicos no mostraron alteración de los órganos estudiados. La parasitemia fue reducida significativamente con la dosis de 300 mg/kg en los días 16° 18° y 20° post infección (p < 0,05). El número de nidos de amastigotes y de infiltrados inflamatorios en corazón fueron reducidos en 67,7% y 51,7%, respectivamente, con 300 mg/kg en el día 28°. Conclusiones: El aceite esencial de Aloysia triphylla es calificado como no tóxico y el citral en dosis de 300 mg/kg tuvo actividad contra Trypanosoma cruzi en ratones.Introduction: There is limited research on neglected diseases. Medicinal plants are potential sources of antimicrobial compounds. Objectives: To determine the toxicity of Aloysia triphylla essential oil and citral activity against Trypanosoma cruzi in mice. Design: Experimental study in vivo, preclinical. Setting: Faculty of Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru. Biological material: Albino mice. Main outcome measures: Signs of toxicity and mortality and parasitemia. Interventions: Acute oral toxicity at single dose was evaluated in albino rats. For trypanocidal activity mice were assigned to the following groups: untreated infected (G1), infected and treated with citral at doses 50, 150 and 300 mg/kg/day (G2, G3 and G4 respectively), infected and treated with benznidazole 100 mg/kg (G5), and uninfected and untreated (G6). Parasitemia was determined individually every 2 days by direct microscopy. In days 14, 21 and 28 post infection five mice from each group were sacrificed and their hearts processed for histopathology. Results: The limit dose of 2 000 mg/kg did not cause signs or symptoms of toxicity and macro and microscopic anatomopathology did not show alterations in the organs studied. Parasitemia was significantly reduced at dose of 300 mg/kg at days 16, 18, and 20 post infection (p <0.05); the number of amastigote nests and inflammatory infiltrates in heart were reduced on day 28 by 67.7% and 51.7% respectively with 300 mg/kg. Conclusions: Aloysia triphylla essential oil is qualified as nontoxic and citral at 300 mg/kg dose had activity against Trypanosoma cruzi in mice

    Metales pesados en tres variedades de Solanum tuberosum L. (papa) expendidos en el mercado mayorista de Santa Anita (Lima-Perú)

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    Vegetables foods are contaminated with heavy metals by different routes, being a risk to the health of the consumer. In this study was performed the quantification of heavy metals cadmium (Cd), lead (Pb), mercury (Hg) and arsenic (As) in fresh tubers of three potato varieties of Solanum tuberosum L. (potato): canchan, huayro and yellow. The samples were randomly collected from 15 stalls in the wholesale market of Santa Anita, province of Lima (Lima - Peru) all from the province of Ambo, department of Huánuco (Peru); 15 samples were collected from each variety with a total of 45 samples. The quantification of Cd and Pb was performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), meanwhile, for the quantification of Hg and As, was used Atomic Fluorescence Spectrometry (AFS).. The Hg concentration ranged from 0,0983 to 0,2594 mg / Kg; Cd from 0,0073 to 0,0287 mg / Kg; Pb from 0,0600 to 0,1018 mg / Kg and As from 0,0003 to 0,0004 mg / Kg. The concentration of Hg in the three varieties far exceeded the maximum limit allowed (MLA) by the European Union (0,02 mg / Kg), therefore, it constitutes a high risk for the consumer. Cd and As concentrations in the three varieties were found below the MLA by Codex Alimentarius and Mercosur; likewise, the Pb in the canchán and huayro varieties were found below the MLA (0,1 mg / Kg); however, in the yellow variety was found a value slightly higher than the MLA.Los alimentos vegetales son contaminados con metales pesados por diferentes vías, constituyendo un riesgo para la salud del consumidor. En este estudio se realizó la cuantificación de los metales pesados: cadmio (Cd), plomo (Pb), mercurio (Hg) y arsénico (As) en tubérculos frescos de tres variedades de Solanum tuberosum L. (papa): canchán, huayro y amarilla. Las muestras se recolectaron al azar de 15 puestos del mercado mayorista de Santa Anita, provincia de Lima (Lima – Perú), todos provenientes de la provincia de Ambo, departamento de Huánuco (Perú); de cada variedad se recolectó 15 muestras teniendo un total de 45 muestras. Para la cuantificación de Cd y Pb se utilizó el método de Espectrometría de Masas de Plasma Acoplado Inductivamente (ICP-MS) y para Hg y As se utilizó la Espectrometría de Fluorescencia Atómica (AFS). La concentración de Hg varió de 0,0983 a 0,2594 mg/Kg; Cd de 0,0073 a 0,0287 mg/Kg; Pb de 0,0600 a 0,1018 mg/Kg y As de 0,0003 a 0,0004 mg/Kg. La concentración de Hg en las tres variedades superó ampliamente el límite máximo permitido (LMP) por la Unión Europea (0,02 mg/Kg), por lo que, constituye un alto riesgo para el consumidor. Las concentraciones de Cd y As en las tres variedades se encontraron por debajo del LMP por Codex Alimentarius y Mercosur; asimismo, el Pb en las variedades canchán y huayro se encontraron por debajo del LMP (0,1 mg/Kg); sin embargo, en la variedad amarilla se encontró un valor ligeramente superior al LMP

    Empirical validation of a usability inspection method for model-driven Web development

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    Web applications should be usable in order to be accepted by users and to improve their success probability. Despite the fact that this requirement has promoted the emergence of several usability evaluation methods, there is a need for empirically validated methods that provide evidence about their effectiveness and that can be properly integrated into early stages of Web development processes. Model-driven Web development processes have grown in popularity over the last few years, and offer a suitable context in which to perform early usability evaluations due to their intrinsic traceability mechanisms. These issues have motivated us to propose a Web Usability Evaluation Process (WUEP) which can be integrated into model-driven Web development processes. This paper presents a family of experiments that we have carried out to empirically validate WUEP. The family of experiments was carried out by 64 participants, including PhD and Master¿s computer science students. The objective of the experiments was to evaluate the participants¿ effectiveness, efficiency, perceived ease of use and perceived satisfaction when using WUEP in comparison to an industrial widely used inspection method: Heuristic Evaluation (HE). The statistical analysis and meta-analysis of the data obtained separately from each experiment indicated that WUEP is more effective and efficient than HE in the detection of usability problems. The evaluators were also more satisfied when applying WUEP, and found it easier to use than HE. Although further experiments must be carried out to strengthen these results, WUEP has proved to be a promising usability inspection method for Web applications which have been developed by using model-driven development processes.The authors would like to thank all the participants in the experiments, along with the usability experts that supported certain tasks of the evaluation design stage, and of which the control group was composed. This research work is funded by the MULTIPLE project (TIN2009-13838) and the FPU program (AP2007-03731) from the Spanish Ministry of Science and Education.Fernández Martínez, A.; Abrahao Gonzales, SM.; Insfrán Pelozo, CE. (2013). Empirical validation of a usability inspection method for model-driven Web development. Journal of Systems and Software. 86(1):161-186. https://doi.org/10.1016/j.jss.2012.07.043S16118686

    The quality of options in strategic decision making: a study about creativity and completeness in business decision making

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    A qualidade das decisões estratégicas dos empresários está diretamente relacionada à capacidade que eles demonstram para encontrar alternativas criativas quando enfrentam os problemas de suas empresas. Essas alternativas podem ser geradas intuitivamente, utilizando heurísticas. As pesquisas sobre geração de alternativas têm indicado consistentemente que as pessoas não são eficientes nessa atividade. As explicações para esse fato, contidas na literatura sobre decisão, não são conclusivas e permitem especulações a respeito. Para explorar essa questão e relacioná-la ao administrador brasileiro, foi idealizado um experimento com 174 alunos de quatro cursos de MBA para avaliar a originalidade e a completude das alternativas. O experimento e a respectiva análise basearam-se na confluência da pesquisa experimental, oriunda da psicologia cognitiva da decisão, com as visões da ciência da decisão organizacional tradicional e o novo campo de estudo das decisões intuitivas ou naturalísticas. Para mensurar a criatividade das alternativas apresentadas durante o experimento, empregou-se o conceito de árvore hierárquica, que demonstrou ser uma poderosa ferramenta para a tipologia de alternativas. O resultado desse experimento confirmou o baixo desempenho em geração de alternativas dos gerentes e, ao mesmo tempo, indicou que, provavelmente, a etapa de geração de alternativas isolada da etapa de escolha pode melhorar a qualidade das alternativas. A heurística, por sua vez, não demonstrou influenciar o conjunto de alternativas geradas. _________________________________________________________________________________________ ABSTRACT: The quality of strategic decisions of executives is directly related to the ability they have to find creative alternatives when facing business problems. These alternatives could be generated intuitively, using heuristics. On the other hand, the researches on alternatives generation have consistently indicated that people are not efficient on this duty. The argument for that, contained in the decision’s literature, is not conclusive and it allows speculation about it. To explore this issue and relate it to the Brazilian Administration, an experiment was designed for 174 students of four courses of MBA. The experiment and the analysis were resulted from the confluence between the experimental research from decision cognitive psychology with science’s vision of the traditional organizational decision and the new field of study on naturalistic or intuitive decisions. To measure the creativity of the alternatives presented during the experiment, the concept of hierarchical tree was utilized and it has proved a powerful tool to the typology of alternatives. The result of this experiment confirmed the poor performance in alternatives generation by managers and at the same time, indicated that probably, the generation of options isolated of analysis can produce better quality of alternatives. The heuristic, do not demonstrated any influence on options generated

    Untitled [Hand and group portrait; He deserted hope]

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    Evan_Leavitt__Milledgeville__GA_February_22__2014_at_1043PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe

    Untitled [Ballet dancer and feather]

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    Evan_Leavitt__Milledgeville__GA_February_22__2014_at_1028PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe

    Untitled [Hand, bottle, prescriptions]

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    Evan_Leavitt__Milledgeville__GA_February_22__2014_at_0958PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe

    Untitled [Hand and group portrait of children; What is your ending]

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    Evan_Leavitt__Milledgeville__GA_February_22__2014_at_1059PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe
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