Mapping functional traits: comparing abundance and presence-absence estimates at large spatial scales

Efforts to quantify the composition of biological communities increasingly focus on functional traits. The composition of communities in terms of traits can be summarized in several ways. Ecologists are beginning to map the geographic distribution of trait-based metrics from various sources of data, but the maps have not been tested against independent data. Using data for birds of the Western Hemisphere, we test for the first time the most commonly used method for mapping community trait composition – overlaying range maps, which assumes that the local abundance of a given species is unrelated to the traits in question – and three new methods that as well as the range maps include varying degrees of information about interspecific and geographic variation in abundance. For each method, and for four traits (body mass, generation length, migratory behaviour, diet) we calculated community-weighted mean of trait values, functional richness and functional divergence. The maps based on species ranges and limited abundance data were compared with independent data on community species composition from the American Christmas Bird Count (CBC) scheme coupled with data on traits. The correspondence with observed community composition at the CBC sites was mostly positive (62/73 correlations) but varied widely depending on the metric of community composition and method used (R2: 5.6×10−7 to 0.82, with a median of 0.12). Importantly, the commonly-used range-overlap method resulted in the best fit (21/22 correlations positive; R2: 0.004 to 0.8, with a median of 0.33). Given the paucity of data on the local abundance of species, overlaying range maps appears to be the best available method for estimating patterns of community composition, but the poor fit for some metrics suggests that local abundance data are urgently needed to allow more accurate estimates of the composition of communities

Home country effects of offshoring. A critical survey on empirical literature.

The International fragmentation of production processes is of rising importance. One part of this fragmentation involves the relocation of a production process from a home- to a new host country. This literature survey deals with the effects of such relocations on the home country. First of all, we try to conceptualize the terms and definitions most frequently used in this context which are "outsourcing", "offshore outsourcing" and "offshoring". Despite the fact that there is little textual documentation dealing directly with the phenomena of offshoring and offshore outsourcing we try to give an overview of possible empirical literature to which one can regard to. Including FDI literature we try to cover empirical literature which can provide helpful insight on the effects of a relocation to foreign countries on the home country in connection with wages, skill upgrading, prices, profits, taxes and unions. (author's abstract)Series: Discussion Papers SFB International Tax Coordinatio

Mapping and Identification of Suitable Dumping Sites for Solid Waste Management in Gwagwalada Area Council of the F.C.T. Nigeria

Urban solid waste is one of the major threats to global environment in the world today. As global civilization keeps improving, there is increase in commercial, residential and infrastructural development due to the population growth which has a negative impact on the environment if not properly planned, monitored and maintained. One of the negative impacts is the problem of waste disposal which if not properly managed could lead to environmental problems and to avoid the negative repercussion of improper waste disposal, an area has to be put in place for solid waste disposal and management also referred to as dump site. Geographical Information System and Remote sensing Techniques were used in the process of site selection which is accurate, less expensive and less time consuming compared to the conventional method. The aim of this study was to identify a suitable sites for solid waste disposal in Gwagwalada town of the Federal Capital Territory (F.C.T), Abuja. An image of the study area was digitized to identify the different features on the ground and also the Digital Terrain Model (DTM) to show differencse in surface elevation. The Digital terrain model shows that the lowest elevation point is 176m while the highest point is 226m above the sea level. Three Data analysis types were used and this includes Buffering, Overlay and Query. The analysis was carried to ascertain that the proposed dump sites pose no threat to agriculture, life and property. The result of all analysis carried out shows that the location of the proposed dump sites is 184m in elevation and 1km off the exit route of Gwagwalada along the Gwagwalada- katse road. It is highly recommended that urban settings should have an open space for dump site on remote areas of little or no economic importance far from the residents and should be monitored properly. Concerned Environmental Maintenance Authorities can now used the knowledge of GIS and Remote Sensing Application in monitoring the environment and improve management. Keywords: Solid Waste, Management, Dump Site, Mapping, Urba

ORDINARY LEAST SQUARES REGRESSION OF ORDERED CATEGORICAL DATA: INFERENTIAL IMPLICATIONS FOR PRACTICE

Ordered categorical responses (OCRs) are frequently encountered in many disciplines. Examples of interest in agriculture include quality assessments, such as for soil or food products, and evaluation of lesion severity, such as teat ends status in dairy cattle. OCRs are characterized by multiple categories recorded on a ranked scale that, while apprising relative order, is not informative of absolute magnitude of or proportionality between the categories. A number of statistically sound models for OCRs are available in the statistical literature, such as logistic regression and probit models, but these are commonly underutilized in practice. Instead, the ordinary least squares linear regression (OLSLR) model is often employed despite violation of basic model assumptions. In this study, the inferential implications of OLSLR-based inference on OCRs were investigated using a simulation study that evaluated realized Type I error rate and empirical statistical power. The design of the simulation study was motivated by applications reported in the subject-matter literature. A variety of plausible scenarios were considered for simulation, including various shapes of the frequency distribution and number of categories of the OCR. Using survey data on frequency of antimicrobial use in cattle feedlots, we illustrated the inferential performance of OLSLR on OCRs relative to a probit model

Basic skin surgery interactive simulation: system description and randomised educational trial

Background: Learning the skills required for open surgery is essential for trainee progression towards more advanced technical procedures. Simulation supports skill enhancement at a time when exposure to actual surgical procedures and traditional apprentice-based teaching has declined. The proliferation of smartphone and tablet devices with rich, touch sensitive displays and increasing processing power makes a compelling argument for expanding accessibility further by development of mobile virtual simulations for training on demand in any setting, at any time.We present a tablet-based mobile simulation App for educating surgical trainees in the planning and surgical procedures involved in facial lesion resection and local skin flap surgery. Methods: Novel algorithms were developed and modules included in a mobile simulation App to teach concepts required for three defect reconstruction techniques: elliptical closure, bilateral advancement (H flap) and the semi-circular rotation flap, with additional resources such as videos and formal guidelines made available at relevant points in the simulation. A randomised educational trial was conducted using the mobile simulation App with 18 medical students that were divided equally into two groups: the intervention group learning using the new mobile simulation App, and a control group, undergoing traditional text-based self-study. The students were then assessed on knowledge and skills' acquisition through an MCQ and a task analysis score. Results: There was a statistically significant difference between the scores of students in the intervention group and the students in the non-intervention group in both forms of assessment, with an average multiple-choice assessment score of 62.95% points versus 56.73%, respectively (p = 0.0285), and an average task analysis score of 3.53 versus 2.58, respectively (p = 0.0139). Conclusions: Touch-based simulation provided an efficient and superior method of learning three different local flap techniques for facial soft tissue reconstruction, and helped recalling steps involved in the surgery in a fluid manner that also improved task performance

ASSESSMENT OF HIV/AIDS PERCEPTION AND PREVENTIVE PRACTICES AMONG RURAL YOUTHS IN NASARAWA STATE, NIGERIA

The research was conducted in Nasarawa State of Nigeria. All rural youths in the state were the target population. A multi stage sampling procedure was adopted in selecting the sampled respondents. A total of 295 respondents were used for the study. Data were collected through the use of interview schedule and questionnaire and analyzed using the Statistical Package for Social Science (SPSS). Both descriptive and inferential statistics were used based on the stated objectives. The findings of the study showed that most (38.31%) of the respondents were within the age group of 21 -25 years. Majority (70.17%) of the respondents were males and single (60%) with secondary school education as the highest qualification. With regards to occupation, most (40.68%) of the respondents were farmers and students respectively. Results on the knowledge of HIV/AIDS by the respondents indicate that majority (50.85%) believed that the disease was a deadly, showing that they were knowledgeable about the deadly nature of the disease. Majority (90.45%) of the respondents ranked abstinence (not having sex before marriage) as the first among the preventive practices they have adopted. The effect of female-male differential in adoption of preventive practices among the sexes was examined by comparing the mean adoption index of the respondents. While the males had a mean adoption index of 0.5844, the females had 0.6203 showing that there was no significant difference in the adoption indices between males and females implying that no particular sex adopted more than the other in the study area. The results of the regression analysis show that sex, marital status, occupation and religion did not have significant effect on the adoption of preventive practices among the respondents. However, education and age were found to be significant. The study therefore, recommends that there is the need for more enlightenment campaigns at different levels including government and nongovernmental bodies’ especially religious groups to further sensitize the youth on HIV/AIDS preventive practices. Key words: HIV/AIDS, Perception, Preventive practices, Rural youths, Nasarawa state

Ground-plane screening of Coulomb interactions in two-dimensional systems: How effectively can one two-dimensional system screen interactions in another?

The use of a nearby metallic ground-plane to limit the range of the Coulomb interactions between carriers is a useful approach in studying the physics of two-dimensional (2D) systems. This approach has been used to study Wigner crystallization of electrons on the surface of liquid helium, and most recently, the insulating and metallic states of semiconductor-based two-dimensional systems. In this paper, we perform calculations of the screening effect of one 2D system on another and show that a 2D system is at least as effective as a metal in screening Coulomb interactions. We also show that the recent observation of the reduced effect of the ground-plane when the 2D system is in the metallic regime is due to intralayer screening.Comment: 14 pages, 7 figures Accepted in PR