Impingement of Water Droplets on a Sphere

Droplet trajectories about a sphere in ideal fluid flow were calculated. From the calculated droplet trajectories the droplet impingement characteristics of the sphere were determined. Impingement data and equations for determining the collection efficiency, the area, and the distribution of impingement are presented in terms of dimensionless parameters. The range of flight and atmospheric conditions covered in the calculations was extended considerably beyond the range covered by previously reported calculations for the sphere

Maximally Localized States in Quantum Mechanics with a Modified Commutation Relation to All Orders

We construct the states of maximal localization taking into account a modification of the commutation relation between position and momentum operators to all orders of the minimum length parameter. To first order, the algebra we use reproduces the one proposed by Kempft, Mangano and Mann. It is emphasized that a minimal length acts as a natural regulator for the theory, thus eliminating the otherwise ever appearing infinities. So, we use our results to calculate the first correction to the Casimir Effect due to the minimal length. We also discuss some of the physical consequences of the existence of a minimal length, culminating in a proposal to reformulate the very concept of "position measurement"

The Nature of Aesthetic Experiences

This dissertation provides a theory of the nature of aesthetic experiences on the basis of a theory of aesthetic values. It results in the formulation of the following necessary conditions for an experience to be aesthetic: (i) it must consist of a (complex) representation of an object and an accompanying feeling; (ii) the representation must instantiate an intrinsic value; and (iii) the feeling must be the recognition of that value and bestow it on the object. Since representations are of intrinsic value for different reasons, there are different kinds of aesthetic experiences (such as sensual or meta-cognitive ones). By means of certain conceptual links, it is possible to extend this account to other aesthetic entities thus enabling the formulation of a general theory of the aesthetic in non-aesthetic terms. In particular, aesthetic values are identical with subjective dispositions to elicit aesthetic experiences under normal conditions. Accordingly, I endorse anti-realism about aesthetic values: their existence, nature and exemplification are mind-dependent, while their ascriptions to objects have genuine truth-values. I back up this account by arguing against the alternative positions that either take aesthetic values to be objective or deny the truth-aptness of their attributions. Furthermore, I put forward a relativist variant of anti-realism according to which ascriptions of different (and seemingly incompatible) aesthetic values to a particular object are all correct, given that the aesthetic experiences involved are made under normal conditions and concern the same aesthetically non-evaluative features of that object. For there is no specifically aesthetic norm (e.g., a specification of “ideal critics”) by means of which one of the faultless aesthetic experiences can be picked out as the only appropriate one. That aesthetic values nevertheless show a normative dimension is ensured by their conformity to a general account of values as capacities to satisfy, or dissatisfy, rational desires

Imagination and the Will

The principal aim of my thesis is to provide a unified theory of imagining, that is, a theory which aspires to capture the common nature of all central forms of imagining and to distinguish them from all paradigm instances of non-imaginative phenomena. The theory which I intend to put forward is a version of what I call the Agency Account of imagining and, accordingly, treats imaginings as mental actions of a certain kind. More precisely, it maintains that imaginings are mental actions that aim at the formation of episodic representations, the content of which is directly determined by what we want them to represent. My defence of this version of the Agency Account happens in two stages. On the one hand, I try to show that it is both extensionally adequate and explanatorily illuminating with respect to those mental states or projects which are clear instances of either imaginative or nonimaginative phenomena. And on the other hand, I seek to demonstrate that the most plausible alternative to the Agency Account - namely the Cognitive Account according to which it is distinctive of imaginings that they are non-cognitive phenomena and thus to be contrasted with perceptions, judgements, and so on - is bound to fail as a unified theory of imagining. The dissertation contains five main parts. In the first, I specify in more detail what a unified account of imagining has to achieve and, in particular, which phenomena it is supposed to capture. The second part presents the Cognitive Account, thereby focussing on Brian O'Shaughnessy's sophisticated version of it; while the third part is reserved for the evaluation and rejection of the Cognitive Account. In the fourth part, I develop my version of the Agency Account of imagining. And the fifth and last part is concerned with the accommodation of potential counterexamples to it

Deformed Heisenberg algebra and minimal length

A one-dimensional deformed Heisenberg algebra $[X,P]=if(P)$ is studied. We answer the question: For what function of deformation $f(P)$ there exists a nonzero minimal uncertainty in position (minimal length). We also find an explicit expression for the minimal length in the case of arbitrary function of deformation.Comment: to be published in JP

A survey study of evidence-based medicine training in US and Canadian medical schools

PURPOSE: The authors conducted a survey examining (1) the current state of evidence-based medicine (EBM) curricula in US and Canadian medical schools and corresponding learning objectives, (2) medical educators\u27 and librarians\u27 participation in EBM training, and (3) barriers to EBM training. METHODS: A survey instrument with thirty-four closed and open-ended questions was sent to curricular deans at US and Canadian medical schools. The survey sought information on enrollment and class size; EBM learning objectives, curricular activities, and assessment approaches by year of training; EBM faculty; EBM tools; barriers to implementing EBM curricula and possible ways to overcome them; and innovative approaches to EBM education. Both qualitative and quantitative methods were used for data analysis. Measurable learning objectives were categorized using Bloom\u27s taxonomy. RESULTS: One hundred fifteen medical schools (77.2%) responded. Over half (53%) of the 900 reported learning objectives were measurable. Knowledge application was the predominant category from Bloom\u27s categories. Most schools integrated EBM into other curricular activities; activities and formal assessment decreased significantly with advanced training. EBM faculty consisted primarily of clinicians, followed by basic scientists and librarians. Various EBM tools were used, with PubMed and the Cochrane database most frequently cited. Lack of time in curricula was rated the most significant barrier. National agreement on required EBM competencies was an extremely helpful factor. Few schools shared innovative approaches. CONCLUSIONS: Schools need help in overcoming barriers related to EBM curriculum development, implementation, and assessment. IMPLICATIONS: Findings can provide a starting point for discussion to develop a standardized competency framework

An RNA replication-center assay for high content image-based quantifications of human rhinovirus and coxsackievirus infections

Background: Picornaviruses are common human and animal pathogens, including polio and rhinoviruses of the enterovirus family, and hepatits A or food-and-mouth disease viruses. There are no effective countermeasures against the vast majority of picornaviruses, with the exception of polio and hepatitis A vaccines. Human rhinoviruses (HRV) are the most prevalent picornaviruses comprising more than one hundred serotypes. The existing and also emerging HRVs pose severe health risks for patients with asthma or chronic obstructive pulmonary disease. Here, we developed a serotype-independent infection assay using a commercially available mouse monoclonal antibody (mabJ2) detecting double-strand RNA. Results: Immunocytochemical staining for RNA replication centers using mabJ2 identified cells that were infected with either HRV1A, 2, 14, 16, 37 or coxsackievirus (CV) B3, B4 or A21. MabJ2 labeled-cells were immunocytochemically positive for newly synthesized viral capsid proteins from HRV1A, 14, 16, 37 or CVB3, 4. We optimized the procedure for detection of virus replication in settings for high content screening with automated fluorescence microscopy and single cell analysis. Our data show that the infection signal was dependent on multiplicity, time and temperature of infection, and the mabJ2-positive cell numbers correlated with viral titres determined in single step growth curves. The mabJ2 infection assay was adapted to determine the efficacy of anti-viral compounds and small interfering RNAs (siRNAs) blocking enterovirus infections. Conclusions: We report a broadly applicable, rapid protocol to measure infection of cultured cells with enteroviruses at single cell resolution. This assay can be applied to a wide range of plus-sense RNA viruses, and hence allows comparative studies of viral infection biology without dedicated reagents or procedures. This protocol also allows to directly compare results from small compound or siRNA infection screens for different serotypes without the risk of assay specific artifacts

Estudio comparativo de las comunidades vegetales de los arrozales y de los ambientes acuáticos y palustres de Entre Ríos (Argentina)

El cultivo de arroz, por su necesidad de estar inundado la mayor parte de su ciclo, es un hábitat apropiado para el establecimiento de malezas acuáticas y palustres. En los ríos y arroyos que sirven como fuente de agua de riego se desarrollan vegetales que se diseminan por semillas o segmentos y brotan posteriormente en las arroceras, constituyéndose en malezas. El objetivo es comparar la composición de las comunidades vegetales de ambientes acuáticos y palustres, y las de áreas del cultivo de arroz inundado, con el fin de evaluar su similitud florística. Entre diciembre de 1993 y febrero de 1995 se relevaron 154 estaciones, censándose la vegetación de 11 ambientes acuáticos y palustres. Se estimó la abundancia y cobertura de las especies y se clasificaron los ambientes según la técnica del vecino más lejano para estimar su similitud entre sí. Se registraron 105 especies vegetales, prevaleciendo por su cobertura las familias Poaceae, Asteraceae, Cyperaceae, Polygonaceae y Apiaceae. El análisis de clasificación mostró que los ambientes florísticamente más similares a las arroceras fueron las contrabanquinas y los arroyos, siendo éstos los que presentaron mayor cobertura total de especies palustres y acuáticas. En los arrozales existe un claro predominio de cobertura de especies helófitas (palustres) respecto de las otras formas biológicas.Flooded rice fields are an appropriate habitat for aquatic and marshy weeds. In rivers and streams are used as water source for flooding of irrigation water, some plants develop and disseminate by seeds or segments, and sprout later on rice fields becoming weeds. The objective was to study the composition of plant communities of aquatic and marshy environments and the fllooding rice crops of Entre Ríos. The study was carried out between December 1993 and February 1995. One hundred and fifty four stations were sampled by censing vegetation of 11 types of aquatic and marshy environments. Species abundance and cover were estimated, and similarity of environments was obtained with euclidean distance and classified according to the most distant neighbor's technique. One hundred and five species were registered, and the prevailing families were Poaceae, Asteraceae, Cyperaceae, Polygonaceae and Apiaceae. Small streams would be the environment with higher contribution of marshy and aquatic weeds, and so they have higher probability of being the source of weed invasions. In the rice fields prevails the covering of marshy species with regard to other biological forms.Facultad de Ciencias Agrarias y Forestale

Estudio comparativo de las comunidades vegetales de los arrozales y de los ambientes acuáticos y palustres de Entre Ríos (Argentina)

El cultivo de arroz, por su necesidad de estar inundado la mayor parte de su ciclo, es un hábitat apropiado para el establecimiento de malezas acuáticas y palustres. En los ríos y arroyos que sirven como fuente de agua de riego se desarrollan vegetales que se diseminan por semillas o segmentos y brotan posteriormente en las arroceras, constituyéndose en malezas. El objetivo es comparar la composición de las comunidades vegetales de ambientes acuáticos y palustres, y las de áreas del cultivo de arroz inundado, con el fin de evaluar su similitud florística. Entre diciembre de 1993 y febrero de 1995 se relevaron 154 estaciones, censándose la vegetación de 11 ambientes acuáticos y palustres. Se estimó la abundancia y cobertura de las especies y se clasificaron los ambientes según la técnica del vecino más lejano para estimar su similitud entre sí. Se registraron 105 especies vegetales, prevaleciendo por su cobertura las familias Poaceae, Asteraceae, Cyperaceae, Polygonaceae y Apiaceae. El análisis de clasificación mostró que los ambientes florísticamente más similares a las arroceras fueron las contrabanquinas y los arroyos, siendo éstos los que presentaron mayor cobertura total de especies palustres y acuáticas. En los arrozales existe un claro predominio de cobertura de especies helófitas (palustres) respecto de las otras formas biológicas.Flooded rice fields are an appropriate habitat for aquatic and marshy weeds. In rivers and streams are used as water source for flooding of irrigation water, some plants develop and disseminate by seeds or segments, and sprout later on rice fields becoming weeds. The objective was to study the composition of plant communities of aquatic and marshy environments and the fllooding rice crops of Entre Ríos. The study was carried out between December 1993 and February 1995. One hundred and fifty four stations were sampled by censing vegetation of 11 types of aquatic and marshy environments. Species abundance and cover were estimated, and similarity of environments was obtained with euclidean distance and classified according to the most distant neighbor's technique. One hundred and five species were registered, and the prevailing families were Poaceae, Asteraceae, Cyperaceae, Polygonaceae and Apiaceae. Small streams would be the environment with higher contribution of marshy and aquatic weeds, and so they have higher probability of being the source of weed invasions. In the rice fields prevails the covering of marshy species with regard to other biological forms.Facultad de Ciencias Agrarias y Forestale

Estudio comparativo de las comunidades vegetales de los arrozales y de los ambientes acuáticos y palustres de Entre Ríos (Argentina)

El cultivo de arroz, por su necesidad de estar inundado la mayor parte de su ciclo, es un hábitat apropiado para el establecimiento de malezas acuáticas y palustres. En los ríos y arroyos que sirven como fuente de agua de riego se desarrollan vegetales que se diseminan por semillas o segmentos y brotan posteriormente en las arroceras, constituyéndose en malezas. El objetivo es comparar la composición de las comunidades vegetales de ambientes acuáticos y palustres, y las de áreas del cultivo de arroz inundado, con el fin de evaluar su similitud florística. Entre diciembre de 1993 y febrero de 1995 se relevaron 154 estaciones, censándose la vegetación de 11 ambientes acuáticos y palustres. Se estimó la abundancia y cobertura de las especies y se clasificaron los ambientes según la técnica del vecino más lejano para estimar su similitud entre sí. Se registraron 105 especies vegetales, prevaleciendo por su cobertura las familias Poaceae, Asteraceae, Cyperaceae, Polygonaceae y Apiaceae. El análisis de clasificación mostró que los ambientes florísticamente más similares a las arroceras fueron las contrabanquinas y los arroyos, siendo éstos los que presentaron mayor cobertura total de especies palustres y acuáticas. En los arrozales existe un claro predominio de cobertura de especies helófitas (palustres) respecto de las otras formas biológicas.Flooded rice fields are an appropriate habitat for aquatic and marshy weeds. In rivers and streams are used as water source for flooding of irrigation water, some plants develop and disseminate by seeds or segments, and sprout later on rice fields becoming weeds. The objective was to study the composition of plant communities of aquatic and marshy environments and the fllooding rice crops of Entre Ríos. The study was carried out between December 1993 and February 1995. One hundred and fifty four stations were sampled by censing vegetation of 11 types of aquatic and marshy environments. Species abundance and cover were estimated, and similarity of environments was obtained with euclidean distance and classified according to the most distant neighbor's technique. One hundred and five species were registered, and the prevailing families were Poaceae, Asteraceae, Cyperaceae, Polygonaceae and Apiaceae. Small streams would be the environment with higher contribution of marshy and aquatic weeds, and so they have higher probability of being the source of weed invasions. In the rice fields prevails the covering of marshy species with regard to other biological forms.Facultad de Ciencias Agrarias y Forestale