Cross-entropy optimizer: a new tool to study precession in astrophysical jets

Evidence of jet precession in many galactic and extragalactic sources has been reported in the literature. Much of this evidence is based on studies of the kinematics of the jet knots, which depends on the correct identification of the components to determine their respective proper motions and position angles on the plane of the sky. Identification problems related to fitting procedures, as well as observations poorly sampled in time, may influence the follow-up of the components in time, which consequently might contribute to a misinterpretation of the data. In order to deal with these limitations, we introduce a very powerful statistical tool to analyse jet precession: the cross-entropy method for continuous multi-extremal optimization. Only based on the raw data of the jet components (right ascension and declination offsets from the core), the cross-entropy method searches for the precession model parameters that better represent the data. In this work we present a large number of tests to validate this technique, using synthetic precessing jets built from a given set of precession parameters. With the aim of recovering these parameters, we applied the cross-entropy method to our precession model, varying exhaustively the quantities associated with the method. Our results have shown that even in the most challenging tests, the cross-entropy method was able to find the correct parameters within a 1 per cent level. Even for a non-precessing jet, our optimization method could point out successfully the lack of precession.

Sexually Dimorphic Tegumental Gland Openings in Laniatores (Arachnida, Opiliones), With New Data on 23 Species

Sexually dimorphic glands often release sexual pheromones both in vertebrates and invertebrates. Species of Laniatores (Arachnida, Opiliones) seem to depend on chemical communication but few studies have addressed this topic. In this study, we review the literature for the Phalangida and present new data for 23 species of Laniatores. In 16 taxa, we found previously undescribed sexually dimorphic glandular openings on the femur, patella, metatarsus, and tarsus of legs I and metatarsus of legs III and IV For the other species, we provide scanning electron micrographs of previously undescribed sexually dimorphic setae and pegs located on swollen regions of the legs. We also list additional species in which males have swollen regions on the legs, including the tibia, metatarsus, and tarsus of legs I, trochanter and tibia of legs II, femur, metatarsus, and tarsus of legs III, and metatarsus and tarsus of legs IV. The function and biological role of the secretions released by these glands are discussed. J. Morphol. 271:641-653, 2010. (C) 2009 Wiley-Liss, Inc.

Hydrocoryne iemanja (Cnidaria), a new species of Hydrozoa with unusual mode of asexual reproduction

Hydrocoryne iemanja sp. nov. was found in an aquarium, growing on rhodoliths of coralline algae collected on the southeastern coast of Brazil (20 degrees 40`S 40 degrees 2`W). The colonies were reared through maturity in the laboratory. Each colony had up to 7 sessile, long and thin monomorphic zooids, very extensible and flexible, arising from a chitinous, hard dark-brown plate with minute spines. Medusae budded from near the basal part of hydrocaulus, and were released in immature condition, acquiring fully developed interradial gonads 5-7 days after release. Asexual reproduction by longitudinal fission was observed on the hydrocaulus of the polyps, both for those in normal condition and those with injuries. Fission started at the oral region, extending aborally, with a new hard plate formed in the basal part of hydrocaulus. When fission reached the new hard plate, the new polyp detached, becoming free and sinking to the bottom, starting a new colony. Detached polyps were morphologically indistinguishable from other polyps, being able to produce medusae. Mother and daughter polyps undertook subsequent fissions. This mode of longitudinal fission is distinct from other modes of longitudinal fission, a process known for a few species Of cnidarians. Further studies of this process may shed light on the understanding of the evolutionary pathways in Cnidaria and animals. Hydrocoryne iemanja sp. nov. is distinguishable from its two congeners by the distinct marginal tentacles of the medusae-short and with a median nematocyst knob-an unambiguous character useful even for the identification Of newly liberated medusae.

The spider genus Chrysometa (Araneae, Tetragnathidae) from the Pico da Neblina and Serra do Tapirapeco mountains (Amazonas, Brazil): new species, new records, diversity and distribution along two altitudinal gradients

Eight new species of the spider genus Chrysometa Simon, 1894 (Araneae, Tetragnathidae) are described and illustrated. Chrysometa nubigena n. sp., C. waikoxi n. sp., C. petrasierwaldae n. sp., C. santosi n. sp., C. yanomami n. sp., C. candianii n. sp., C. lomanhungae n. sp., and C. saci n. sp. Those species were collected in a study on the diversity of spider communities along altitudinal gradients in Brazilian Amazonia. C. saci was captured at the Serra do Tapirapeco (Barcelos), while all the other species are from the Pico da Neblina (Sao Gabriel da Cachoeira), the highest mountain in Brazil. We provide new records for C. boraceia, C. flava, C. guttata, C. minuta and C. opulenta, and we describe the male of C. minuta for the first time. We also present the first results on the diversity and altitudinal distribution of the species of Chrysometa at the Pico da Neblina and Serra do Tapirapeco. We sampled the first locality at six different elevations, and obtained 336 specimens distributed in 12 species. Richness and abundance, as well as relative importance peaked at the highest sites sampled (2,000 and 2,400 m). The three most abundant species showed a segregated distribution, being dominant or exclusively distributed in different altitudes. At the Serra do Tapirapeco, sampling at four different elevations up to 1200 m, we only obtained 40 individuals divided in four species, and there was no clear relation to altitude. Most of the new species were found at mid and high altitude sites, while species from lower altitude sites represented widespread species. The comparison with other neotropical spiders inventories highlights the high diversity recorded at Pico da Neblina, which could be assigned to the large environmental variation covered in this work and to the sampling of high-altitude environments. Inventories in the Andean region and other information in the literature also seem to support the association of Chrysometa with high altitude environments.

Investigation of a new GRASP-based clustering algorithm applied to biological data

A large amount of biological data has been produced in the last years. Important knowledge can be extracted from these data by the use of data analysis techniques. Clustering plays an important role in data analysis, by organizing similar objects from a dataset into meaningful groups. Several clustering algorithms have been proposed in the literature. However, each algorithm has its bias, being more adequate for particular datasets. This paper presents a mathematical formulation to support the creation of consistent clusters for biological data. Moreover. it shows a clustering algorithm to solve this formulation that uses GRASP (Greedy Randomized Adaptive Search Procedure). We compared the proposed algorithm with three known other algorithms. The proposed algorithm presented the best clustering results confirmed statistically. (C) 2009 Elsevier Ltd. All rights reserved.

TEM, XRD and AFM study of poly(o-ethoxyaniline) films: new evidence for the formation of conducting islands

The existence of conducting islands in polyaniline films has long been proposed in the literature, which would be consistent with conducting mechanisms based on hopping. Obtaining direct evidence of conducting islands, however, is not straightforward. In this paper, conducting islands were visualized in poly(o-ethoxyaniline) (POEA) films prepared at low pH, using Transmission Electron Microscopy (TEM) and atomic force spectroscopy (AFS). The size of the islands varied between 67 and 470 angstrom for a pH=3.0, with a larger average being obtained with AFS, probably due to the finite size effect of the atomic force microscopy tip. In AFS, the conducting islands were denoted by regions with repulsive forces due to the double-layer forces. On the basis of X-ray diffraction (XRD) patterns for POEA in the powder form, we infer that the conducting islands are crystalline, and therefore a POEA film is believed to consist of conducting islands dispersed in an insulating, amorphous matrix. From conductivity measurements we inferred the charge transport to be governed by a typical quasi-one dimensional variable range hopping (VRH) mechanism.

Evaluating Projects in a Dynamic Economy: Some New Envelope Results

This paper is concerned with the modern theory of social cost-benefit analysis in a dynamic economy. The theory emphasizes the role of a comprehensive, forward-looking, dynamic welfare index within the period of the project rather than that of a project's long-term consequences. However, what constitutes such a welfare index remains controversial in the recent literature. In this paper, we attempt to shed light on the issue by deriving three equivalent cost-benefit rules for evaluating a small project. In particular, we show that the direct change in net national product (NNP) qualifies as a convenient welfare index without involving any other induced side effects. The project evaluation criterion thus becomes the present discounted value of the direct changes in NNP over the project period. We also illustrate the application of this theory in a few stylized examples.

ICT as a tool in English teaching : A literature review on the use of ICT for Swedish students with learning difficulties and their literacy learning in grades 7-9

Information and communication technology (ICT) is a subject that is being discussed as a tool that is used within education around the world. Furthermore it can be seen as a tool for teachers to individualize students´ education. Students with literacy difficulties, such as dyslexia, are in constant need of new ways to learn, and new ways to be motivated to learn. The aim of this study is to see what research says in regard to how ICT can be used as a tool to help students with literacy difficulties. Literacy difficulties can be due to a number of things, such as the student has not been taught how to read, trouble within the family which can cause distress, or a neurological disorder such as dyslexia. Furthermore, the main research questions will focus on how ICT can be compared to traditional education forms, such as books and a more teacher centered education within the classroom, and whether ICT can be preferred. The results of this literature review indicates that ICT can be seen as a way for teachers to help students with literacy difficulties gain more self-esteem – something the literature tells us students with learning difficulties lack. The results also show how ICT can lead to a more individualized education. This is due to tools that increase reading comprehension and tools that give direct response when working with ICT, which helps students work more independently.

Students’ Perspectives on Extensive Literature : Using Literature to Enhance Communicative Competence and Cultural Understanding in the EFL-Classroom

The aim of this thesis is to investigate the use of literature within the Swedish Upper Secondary EFL-classroom from the students’ perspective. How do the students in the study relate to literature and its use to enhance and enable their communicative competence and cultural understanding? Also, how do their answers compare with their teacher’s and the adult perspectives and findings from previous international research? The empirical data obtained from the study has been analysed from the perspectives of sociocultural and motivational theory, and the findings show that the participating students believe literature to be a good didactic tool to apply in the EFL-classroom, both in order to enhance their communicative competence and their cultural understanding. The students prefer to have a sociocultural approach to their literature-learning, with group-discussions of various sizes. The key for the students in this respect is interesting, relevant and engaging subject-matter, as well as a positive and motivational teacher. The responses given by the students correlate with those given by their teacher as well as previous international research. The students regard literature as a way of gaining new perspectives, as well as experiencing language in use. Where they diverge somewhat from the international research is in regard to literature’s use for enhancing their competence to speak in class, and that some students seem to think that communication and cultural understanding are separable. Future studies within this field might include the conducting of a larger and more in-depth survey regarding the students’ ideas about literature, culture and communication. Why do so many of the student respondents neither agree nor disagree with the statement concerning communication and cultural understanding being inseparable? This can be an important issue to investigate in today’s global climate of cross-cultural and intercultural experiences, especially in view of the political climate of diverse attitudes towards refugees, immigrants and emigration

Children’s Literature and English Teaching – Swedish Teachers’ Methods and Attitudes

This study investigates how primary school teachers of grades F-3 pupils in a number of sample schools in Sweden use children’s literature and other methods to enhance their teaching of English. The study explores the attitudes of these teachers’ to using English children’s literature as a teaching tool to promote language development in their pupils, focusing on vocabulary. An empirical questionnaire study was carried out including a total of twenty-three respondents from seven schools in a Stockholm suburb. The respondents are all working teachers with experience of teaching English to young learners, particularly in grades F-3. This study contributes with new knowledge about the often-recommended use of children’s literature as a method for teaching English to young learners, connecting international research with empirical data from the Swedish context. While the results suggest that the majority of the respondents are positive to using children’s literature in their teaching and regularly do so, many of them feel that it is somewhat difficult to find relevant materials to plan, implement and evaluate lessons within the allocated time-frame. Based on these results, further research about how to create more effective ways of using children’s literature as a method for English vocabulary teaching in Swedish schools is recommended.

Shared-decision making in designing new healthcare environments : ready to take off for improved quality

Background Successful implementation of new methods and models of healthcare to achieve better patient outcomes and safe, person-centered care is dependent on the physical environment of the healthcare architecture in which the healthcare is provided. Thus, decisions concerning healthcare architecture are critical because it affects people and work processes for many years and requires a long-term financial commitment from society. In this paper, we describe and suggest several strategies (critical factors) to promote shared-decision making when planning and designing new healthcare environments. Discussion This paper discusses challenges and hindrances observed in the literature and from the authors extensive experiences in the field of planning and designing healthcare environments. An overview is presented of the challenges and new approaches for a process that involves the mutual exchange of knowledge among various stakeholders. Additionally, design approaches that balance the influence of specific and local requirements with general knowledge and evidence that should be encouraged are discussed. Summary We suggest a shared-decision making and collaborative planning and design process between representatives from healthcare, construction sector and architecture based on evidence and end-users’ perspectives. If carefully and systematically applied, this approach will support and develop a framework for creating high quality healthcare environments.

Scriptural Archeology: Excavating the Presence of Women in the Torah

Women's roles in religious history have been traditionally described in terms of their relation and value to men. The normative religious texts provide an androcentric perspective on the gender relationships within the early community, the growth of Judaism in "Jacob's House" and the monotheistic worship of God. Yet these literary representations omit an entire half of the experience of the Jewish community: the perspective and participation of women. As Judith Plaskow argues extensively in Standing Again at Sinai, women are defined not in her own terms or in her own voice, but by her relationship and value to men through the androcentric vocabulary of the Torah. This statement is textually illustrated by the authorial and editorial presentation of women and their place in ancient Israelite society in the Torah. As Judaism grew increasingly androcentric in its leadership, women were increasingly reduced to marginal figures in the community by authorial and editorial revisions. Yet the participation of women of ancient Israel is not lost. Instead, the presence of women is buried beneath the androcentric presentation of the early Judaic community, waiting to be excavated by historical and scriptural examination. The retelling of the past is influenced by the present; memory is not static but takes on different shapes depending on the focus of concentration. However, tradition greatly influences the interpretation of religious history as well. In the book of Genesis, the literature emphasizes the divine appointment of male figures such as Abraham the father of the covenant and Jacob who is renamed and claimed by God as "Israel," placing them at the center of Jewish history. As a result, the other figures in these biblical narratives are described in relation to the patriarchs, those male bearers of the covenant, by their service or their value to him. Women are at the bottom of this hierarchy. Although female figures of exceptional quality are noted in later chronicles, such as Ruth, Deborah and Miriam, it is the very nature of their exception that highlights the androcentric editorial focus of the Torah. I agree with Peggy Day, whose own scriptural examination in Gender and Difference in Ancient Israel, makes the important distinction between the literary representation and the reality of ancient Israelite culture: they are not coextensive nor equivalent. Although the text represents the culture of ancient Israel as male dominated from the time of Abraham, this presentation omits the perspective of half of the population-the women. By beginning at the point of realization that women did exist and were active in their culture, and placing aside the androcentric perspective of the text and its editors, the reality of women's place in ancient Israel may be determined. Through this new perspective, the women of the Torah will emerge as the archetypes of strength, leadership and spiritual insight to provide Jewish women of the present with female, ancestral role models and a foundation for their gender's heritage, a more complete understanding of the partial record of Jewish history recorded in the Torah. Those stories that appear as the exception of women's presence will unveil an exceptional presence. As Tamar Frankiel eloquently states in The Voice of Sarah, "the women we call our 'Mothers'-Sarah, Rivkah (Rebekah), Rachel, and Leah-are not merely mothers, any more than the 'Fathers'-Abraham, Isaac and Jacob-are merely fathers "(Frankiel 5).

Estimating Stormwater Runoff for Community Gardens in New York City

While much of the literature cites community gardens as providing urban ecosystem services, there is very little research quantifying these benefits. This thesis compares the stormwater runoff rates of urban vacant lots, community gardens, and residential developments in New York City and evaluates community gardens as green infrastructure.

Gestão do conhecimento e criação de valor: um estudo exploratório em empresas brasileiras

Nos últimos dez anos a gestão do conhecimento tem crescido em importância tanto no meio acadêmico como empresarial. Ainda que alguns permaneçam céticos, sua relevância para a competitividade das organizações tem se tornado cada vez mais um ponto de concordância nos dois ambientes, como uma resposta aos desafios sociais e econômicos impostos. Estes desafios impulsionam a gestão do conhecimento vista como uma disciplina interdisciplinar focada nos agentes e no seu ambiente, e no processo de criação, mapeamento e transferência do conhecimento, com o objetivo final de gerar vantagens competitivas sustentáveis. Apesar de muitos estudos específicos, ainda são poucos os trabalhos que buscam avaliar a adoção da gestão do conhecimento como abordagem ampla, quase como um novo paradigma gerencial adaptado à nova realidade econômica vigente, assim como são poucos os estudos que buscam avaliar o impacto na criação de valor de estratégias focadas no conhecimento. Este trabalho visa preencher essa lacuna, avaliando a adoção de práticas, conceitos e atitudes vinculadas à gestão do conhecimento em empresas de grande e pequeno porte criadoras de valor, através de estudos de caso. Para isso, o trabalho partiu de uma ampla revisão da literatura em torno do tema para definir um conjunto de práticas associadas ao conceito de gestão do conhecimento, dividido em seis dimensões: estratégia, estrutura, tecnologia da informação, cultura e pessoas, sistemas de suporte e processos. A partir deste levantamento, instrumentos distintos – questionário e roteiro de entrevista - foram elaborados para estudar as grandes e pequenas empresas. A pesquisa de campo só foi realizada após a validação do instrumento por especialistas na área, que avaliaram cada item com relação a sua total, parcial ou marginal associação ao conceito de gestão do conhecimento. Os resultados mostram que, independente do tamanho, as empresas criadoras de valor adotam muitas das práticas associadas a gestão do conhecimento em cinco das seis dimensões estudadas. Além destes indícios, o trabalho também contribui ao deixar um rol de mais de duzentos e trinta itens validados com relação ao conceito de gestão do conhecimento, que podem ser testados e aperfeiçoados.