How generic language extensions enable ''open-world'' design in Java

By \emph{open--world design} we mean that collaborating classes are so loosely coupled that changes in one class do not propagate to the other classes, and single classes can be isolated and integrated in other contexts. Of course, this is what maintainability and reusability is all about. In the paper, we will demonstrate that in Java even an open--world design of mere attribute access can only be achieved if static safety is sacrificed, and that this conflict is unresolvable \emph{even if the attribute type is fixed}. With generic language extensions such as GJ, which is a generic extension of Java, it is possible to combine static type safety and open--world design. As a consequence, genericity should be viewed as a first--class design feature, because generic language features are preferably applied in many situations in which object--orientedness seems appropriate. We chose Java as the base of the discussion because Java is commonly known and several advanced features of Java aim at a loose coupling of classes. In particular, the paper is intended to make a strong point in favor of generic extensions of Java

Embracing Geographic Analysis Beyond Geography - Harvard's Center for Geographic Analysis Enters its 5th Year

Without a department of geography, Harvard University established the Center for Geographic Analysis (CGA) in 2006 to support research and teaching of all disciplines across the University with emerging geospatial technologies. In the past four and a half years, CGA built an institutional service infrastructure and unleashed an increasing demand on geographic analysis in many fields. CGA services range from helpdesk, project consultation, training, hardware/software administration, community building, to system development and methodology research. Services often start as an application of existing GIS technology, eventually contributing to the study of geographic information science in many ways. As a new generation of students and researchers growing up with Google Earth and the like, their demand for geospatial services will continue to push CGA into new territories.East Asian Languages and Civilization

Semen quality and reproductive hormones in Faroese men: a cross-sectional population-based study of 481 men

Objectives To determine semen quality and reproductive hormone levels in young Faroese men. Design Descriptive cross-sectional study of Faroese men compared with Danish men. Setting Faroese one-centre study. Participants 481 men born from 1981 to 1987 and investigated from 2007 to 2010. Outcome measures Sperm concentration, semen volume, total sperm count, sperm motility, sperm morphology and reproductive hormone levels. Results Sperm concentrations for the Faroese men were lower than for the Danish men (crude median 40 vs 48 mill/ml, p<0.0005). Semen volume was higher, and thus the total sperm counts did not differ (159 vs 151 mill, p=0.2). Motility and morphology did not differ between the Faroese and Danes. The inhibin B/follicle-stimulating hormone ratios for the Faroese men were lower than for the Danes (64 vs 76, p=0.001). Similarly, lower total testosterone/luteinising hormone (LH) ratio (4.6 vs 6.0, p<0.0005) and lower calculated free-testosterone/LH ratio (94 vs 134, p<0.0005) were detected for the Faroese men. Conclusions Semen quality among the Faroese men is at the same low level as reported for Danish men, and the reproductive hormone levels furthermore indicated a lower Leydig cell capacity for testosterone production. The influence of environmental exposure and genetic factors on semen quality has to be studied further

Allergy and Sensitization during Childhood Associated with Prenatal and Lactational Exposure to Marine Pollutants

Background: Breast-feeding may affect the risk of developing allergy during childhood and may also cause exposure to immunotoxicants, such as polychlorinated biphenyls (PCBs), which are of concern as marine pollutants in the Faroe Islands and the Arctic region. Objectives: The objective was to assess whether sensitization and development of allergic disease is associated with duration of breast-feeding and prenatal or postnatal exposures to PCBs and methylmercury. Methods: A cohort of 656 singleton births was formed in the Faroe Islands during 1999–2001. Duration of breast-feeding and history of asthma and atopic dermatitis were recorded at clinical examinations at 5 and 7 years of age. PCB and mercury concentrations were determined in blood samples obtained at parturition and at follow-up. Serum from 464 children (71%) at 7 years of age was analyzed for total immunoglobulin E (IgE) and grass-specific IgE. Results: The total IgE concentration in serum at 7 years of age was positively associated both with the concomitant serum PCB concentration and with the duration of breast-feeding. However, the effect only of the latter was substantially attenuated in a multivariate analysis. A raised grass-specific IgE concentration compatible with sensitization was positively associated with the duration of breast-feeding and inversely associated with prenatal methylmercury exposure. However, a history of asthma or atopic dermatitis was not associated with the duration of breast-feeding, although children with atopic dermatitis had lower prenatal PCB exposures than did nonallergic children. Conclusions: These findings suggest that developmental exposure to immunotoxicants may both increase and decrease the risk of allergic disease and that associations between breast-feeding and subsequent allergic disease in children may, at least in part, reflect lactational exposure to immunotoxic food contaminants

WorldMap – A Geospatial Framework for Collaborative Research

WorldMap is a web-based, map-centric data exploration system built on open-source geospatial technology at Harvard University. It is designed to serve collaborative research and teaching, but is also accessible to the general public. This article explains WorldMap's basic functions through several historical research projects, demonstrating its flexible scale (from neighborhood to continent) and diverse research themes (social, political, economic, cultural, infrastructural, etc.). Also shared in this article are our experiences in handling technical and institutional challenges during system development, such as synchronization of software components being developed by multiple organizations; juggling competing priorities for serving individual requests and developing a system that will enable users to support themselves; balancing promotion of the system usage with constraints on infrastructure investment; harnessing volunteered geographic information while managing data quality; as well as protecting copyrights, preserving permanent links and citations, and providing long-term archiving.East Asian Languages and Civilization

Phase Synchronization in Railway Timetables

Timetable construction belongs to the most important optimization problems in public transport. Finding optimal or near-optimal timetables under the subsidiary conditions of minimizing travel times and other criteria is a targeted contribution to the functioning of public transport. In addition to efficiency (given, e.g., by minimal average travel times), a significant feature of a timetable is its robustness against delay propagation. Here we study the balance of efficiency and robustness in long-distance railway timetables (in particular the current long-distance railway timetable in Germany) from the perspective of synchronization, exploiting the fact that a major part of the trains run nearly periodically. We find that synchronization is highest at intermediate-sized stations. We argue that this synchronization perspective opens a new avenue towards an understanding of railway timetables by representing them as spatio-temporal phase patterns. Robustness and efficiency can then be viewed as properties of this phase pattern

Children’s white blood cell counts in relation to developmental exposures to methylmercury and persistent organic pollutants

Background: To explore possible markers of developmental immunotoxicity, we prospectively examined 56 children to determine associations between exposures to mercury and persistent organic pollutants since birth and the comprehensive differential counts of white blood cells (WBC) at age 5 years. Materials and methods: Extended differential count included: neutrophils, eosinophils, basophils, lymphocytes (including T cells, NK cells, and B cells), and monocytes. Organochlorine compounds (OCs) including polychlorinated biphenyls (PCBs) and pesticides, five perfluoroalkyl substances (PFASs), and mercury (Hg) were measured in maternal (n=56) and children’s blood at 18 months (n=42) and 5 years (n=56). We constructed latent functions for exposures at three different ages using factor analyses and applied structural equations models adjusted for covariates. Results: Prenatal mercury exposure was associated with depleted total WBC, especially for lymphocytes, where a one standard deviation (SD) increase in the exposure was associated with a decrease by 23% SD (95% CI: -43, -4) in the cell count. Prenatal exposure to OCs was marginally associated with decreases in neutrophil counts. In contrast, the 5-year PFASs concentrations were associated with higher basophil counts (B= 46% SD, 95% CI: 13, 79). Significantly reduced subpopulations of lymphocytes such as B cells, CD4-positive T helper cells and CD4 positive recent thymic emigrants may suggest cellular immunity effects and dysregulation of T-cell mediated immunity. Conclusion: Thus prenatal exposure to mercury and PFASs appears to have differential impacts on WBC counts

On the possibility of magneto-structural correlations: detailed studies of di-nickel carboxylate complexes

A series of water-bridged dinickel complexes of the general formula [Ni&lt;sub&gt;2&lt;/sub&gt;(μ&lt;sub&gt;2&lt;/sub&gt;-OH&lt;sub&gt;2&lt;/sub&gt;)(μ2- O&lt;sub&gt;2&lt;/sub&gt;C&lt;sup&gt;t&lt;/sup&gt;Bu)&lt;sub&gt;2&lt;/sub&gt;(O&lt;sub&gt;2&lt;/sub&gt;C&lt;sup&gt;t&lt;/sup&gt;Bu)2(L)(L0)] (L = HO&lt;sub&gt;2&lt;/sub&gt;C&lt;sup&gt;t&lt;/sup&gt;Bu, L0 = HO&lt;sub&gt;2&lt;/sub&gt;C&lt;sup&gt;t&lt;/sup&gt;Bu (1), pyridine (2), 3-methylpyridine (4); L = L0 = pyridine (3), 3-methylpyridine (5)) has been synthesized and structurally characterized by X-ray crystallography. The magnetic properties have been probed by magnetometry and EPR spectroscopy, and detailed measurements show that the axial zero-field splitting, D, of the nickel(ii) ions is on the same order as the isotropic exchange interaction, J, between the nickel sites. The isotropic exchange interaction can be related to the angle between the nickel centers and the bridging water molecule, while the magnitude of D can be related to the coordination sphere at the nickel sites