On the locus formed by the maximum heights of projectile motion with air resistance

We present an analysis on the geometrical place formed by the set of maxima of the trajectories of a projectile launched in a media with linear drag. Such a place, the locus of apexes, is written in term of the Lambert $W$ function in polar coordinates, confirming the special role played by this function in the problem. In order to characterize the locus, a study of its curvature is presented in two parameterizations, in terms of the launch angle and in the polar one. The angles of maximum curvature are compared with other important angles in the projectile problem. As an addendum, we find that the synchronous curve in this problem is a circle as in the drag-free case.Comment: 7 pages, 6 color eps figures. Synchronous curve added. Typos and style corrected

Coordination Implications of Software Coupling in Open Source Projects

The effect of software coupling on the quality of software has been studied quite widely since the seminal paper on software modularity by Parnas [1]. However, the effect of the increase in software coupling on the coordination of the developers has not been researched as much. In commercial software development environments there normally are coordination mechanisms in place to manage the coordination requirements due to software dependencies. But, in the case of Open Source software such coordination mechanisms are harder to implement, as the developers tend to rely solely on electronic means of communication. Hence, an understanding of the changing coordination requirements is essential to the management of an Open Source project. In this paper we study the effect of changes in software coupling on the coordination requirements in a case study of a popular Open Source project called JBoss

TRANSCRIPTIONAL ANALYSIS OF RETINAL AND FOREBRAIN PROGENITOR CELLS DERIVED FROM HUMAN INDUCED PLURIPOTENT STEM CELLS

poster abstractEye development has been extensively studied in traditional model sys-tems but studies related to humans have been limited. The recent develop-ment of induced pluripotent stem cells (iPSCs) enabled the study of human development in culture at stages that would otherwise be inaccessible to in-vestigation. By definition, Pluripotent stem cells are cells that have the ca-pacity to generate any adult cell type, such as the muscle cell or the blood cell. A defined set of genes, known as eye field transcription factors (EFTFs) have proven to play an important role in eye development. Utilizing iPSCs as our model system, we sought to identify EFTFs that might play an essential role in the specification of the retina of the human eye. iPSCs were directed to develop into retinal cells as previously estab-lished. Since these events occur early in the developmental process, sam-ples were collected every two days over the first twenty days of differentia-tion. The development of retinal cells was determined by the characteriza-tion of gene expression patterns of six EFTFs over this timecourse in order to highlight important trends in retinal development. Retinal populations were identified by the expression of numerous EFTFs which were absent from other non-retinal cell types. Our preliminary data utilizing iPSCs highlights similar trends in the expression of these EFTFs as anticipated. However, the expression patterns of two key EFTFs varied from the others in a manner which implicated them to be critical for retinal devel-opment from an unspecified stem cell source. Thus, these candidate EFTFs were investigated further to establish their specific roles in retinal develop-ment using a combination of genetic and molecular biology approaches. The work presented in this study helps to elucidate the mechanisms by which retinal cells are specified and help establish iPSCs as a unique model system for studies of human development. 1also Indiana University Center for Regenerative Biology and Medicine, Indiana University Department of Medical and Molecular Genetics, and Stark Neurosciences Research Institute, Indianapolis IN 46202 This work was supported by a grant from the Indiana University Collaborative Research Grant fund of the Office of the Vice president for Research as well as startup funds from the School of Science at IUPUI

Rapid redistribution of agricultural land alters avian richness, abundance, and functional diversity

The conversion of natural, or seminatural, habitats to agricultural land and changes in agricultural land use are significant drivers of biodiversity loss. Within the context of land‐sharing versus land‐sparing debates, large‐scale commercial agriculture is known to be detrimental to biodiversity, but the effects of small‐scale subsistence farming on biodiversity are disputed. This poses a problem for sustainable land‐use management in the Global South, where approximately 30% of farmland is small‐scale. Following a rapid land redistribution program in Zimbabwe, we evaluated changes in avian biodiversity by examining richness, abundance, and functional diversity. Rapid land redistribution has, in the near term, resulted in increased avian abundance in newly farmed areas containing miombo woodland and open habitat. Conversion of seminatural ranched land to small‐scale farms had a negative impact on larger‐bodied birds, but species richness increased, and birds in some feeding guilds maintained or increased abundance. We found evidence that land‐use change caused a shift in the functional traits of the communities present. However, functional analyses may not have adequately reflected the trait filtering effect of land redistribution on large species. Whether newly farmed landscapes in Zimbabwe can deliver multiple benefits in terms of food production and habitat for biodiversity in the longer term is an open question. When managing agricultural land transitions, relying on taxonomic measures of diversity, or abundance‐weighted measures of function diversity, may obscure important information. If the value of smallholder‐farmed land for birds is to be maintained or improved, it will be essential to ensure that a wide array of habitat types is retained alongside efforts to reduce hunting and persecution of large bird species

Sekolah Luar Biasa Bagian B Di Manado ”Arsitektur Bagi Penyandang Cacat Tunarungu, Mata Yang Mendengar”

Karakteristik yang dimiliki oleh seorang penyandang cacat tunarungu berbeda dengan orang normal. Kekurangan mereka dalam indera pendengaran menyebabkan mereka kesulitan dalam bersekolah dan kesulitan dalam mencari pekerjaan. Di Kota Manado, para penyandang cacat tunarungu hanya bersekolah dengan menumpang di sekolah-sekolah luar biasa yang lain. Hal ini dapat menyebabkan kurang efektifnya sistem pembelajaran bagi anak-anak penyandang cacat tunarungu. Untuk itulah sangat dibutuhkan sarana dan prasarana yang memadai guna untuk mencerdaskan anak-anak penyandang cacat tunarungu. Perancangan Sekolah Luar Biasa bagian B di Manado sangat dibutuhkan oleh anak-anak tunarungu dengan memakai tema ”arsitektur bagi penyandang cacat tunarungu, mata yang mendengar” bertujuan untuk merancang Sekolah Luar Biasa bagian B yang didalamnya mereka tidak saja menuntut ilmu, tapi juga dapat melatih diri mereka sendiri agar ketika berada di dunia luar, mereka tidak dianggap rendah oleh orang-orang normal

A distributed data component for the Open Modeling Interface

As the volume of collected data continues to increase in the environmental sciences, so too does the need for effective means for accessing those data. We have developed an Open Modeling Interface (OpenMI) data component that retrieves input data for model components from environmental information systems and delivers output data to those systems. The adoption of standards for both model component input–output interfaces and web services make it possible for the component to be reconfigured for use with different linked models and various online systems. The data component employs three techniques tailored to the unique design of the OpenMI that enable efficient operation: caching, prefetching, and buffering, making it capable of scaling to large numbers of simultaneous simulations executing on a computational grid. We present the design of the component, an evaluation of its performance, and a case study demonstrating how it can be incorporated into modeling studies

Catalytic Nucleophilic Glyoxylation of Aldehydes

β-Silyloxy-α-ketoesters are prepared through a cyanide-catalyzed benzoin-type reaction with silyl glyoxylates and aldehydes. The products undergo a dynamic kinetic resolution to provide enantioenriched orthogonally protected alcohols and can be converted to the corresponding β-silyloxy-α-aminoesters

Asymmetric Synthesis of α-Keto Esters via Cu(II)-Catalyzed Aerobic Deacylation of Acetoacetate Alkylation Products: An Unusually Simple Synthetic Equivalent to the Glyoxylate Anion Synthon

A simple and efficient method for the preparation of β-stereogenic α-keto esters is described using a copper(II)-catalyzed aerobic deacylation of substituted acetoacetate esters. The substrates for the title process arise from catalytic, enantioselective conjugate additions and alkylation reactions of acetoacetate esters. The mild conditions do not induce racemization of the incipient enolizable α-keto ester. The reaction is tolerant of esters, certain ketones, ketals, and nitro groups and utilizes inexpensive, readily available materials

(G)hosting television: Ghostwatch and its medium

This article’s subject is Ghostwatch (BBC, 1992), a drama broadcast on Halloween night of 1992 which adopted the rhetoric of live non-fiction programming, and attracted controversy and ultimately censure from the Broadcasting Standards Council. In what follows, we argue that Ghostwatch must be understood as a televisually-specific artwork and artefact. We discuss the programme’s ludic relationship with some key features of television during what Ellis (2000) has termed its era of ‘availability’, principally liveness, mass simultaneous viewing, and the flow of the television super-text. We trace the programme’s television-specific historicity whilst acknowledging its allusions and debts to other media (most notably film and radio). We explore the sophisticated ways in which Ghostwatch’s visual grammar and vocabulary and deployment of ‘broadcast talk’ (Scannell 1991) variously ape, comment upon and subvert the rhetoric of factual programming, and the ends to which these strategies are put. We hope that these arguments collectively demonstrate the aesthetic and historical significance of Ghostwatch and identify its relationship to its medium and that medium’s history. We offer the programme as an historically-reflexive artefact, and as an exemplary instance of the work of art in television’s age of broadcasting, liveness and co-presence