6,359 research outputs found
The Integral Role of Borough of Manhattan Community College in the Mathematics Preparation of Prospective Teachers
Borough of Manhattan Community College (BMCC) of the City University of New York (CUNY) is the only two-year college on the island of Manhattan. This institution has a diverse population of approximately 17,000 students who attend day/evening/weekend classes. Over 1,000 students are enrolled in the Early Childhood Education (ECE) Program. Each year, approximately 300 new students select this area of concentration. The dropout rate is less than 14%. The ECE Program prepares students for elementary education programs at four-year institutions. The program also offers two career areas of study: Infant Toddler and Pre-School. This article will discuss how high quality teacher preparation at BMCC is promoted through mathematics coursework recommended by the NCTM and AMATYC for prospective elementary school teachers, the importance of technology in providing enriching pre-teaching experiences, collaboration with four-year institutions in teacher preparation efforts, and the importance of special teacher preparation of underrepresented populations for underrepresented populations of New York City
RCA SATCOM Battery in Orbit Performance Update and Accelerated Life Test Results
No significant degradation of nickel cadmium battery performance in SATCOM F1 and F2 after almost 8 and 7-3/4 years in orbit was shown. Battery minimum discharge voltage data are presented for these spacecraft. In addition, 2 groups of nickel cadmium cells which are representative of those in orbit are undergoing real time eclipse-reduced suntime cycling in the laboratory. These groups of cells, which are being cycled at a maximum of 53% and 62% depth of discharge (based on actual capacity), have completed 14 and 15 eclipse seasons, respectively. Data for these groups of cells are presented and are compared with the in-orbit battery data
Geographic range size and evolutionary age in birds
Together with patterns of speciation and extinction, post-speciation transformations in the range sizes of individual species determine the form of contemporary species-range-size distributions. However, the methodological problems associated with tracking the dynamics of a species' range size over evolutionary time have precluded direct study of such range-size transformations, although indirect evidence has led to several models being proposed describing the form that they might take. Here, we use independently derived molecular data to estimate ages of species in six monophyletic groups of birds, and examine the relationship between species age and global geographic range size. We present strong evidence that avian range sizes are not static over evolutionary time. In addition, it seems that, with the regular exception of certain taxa (for example island endemics and some threatened species), range-size transformations are non-random in birds. In general, range sizes appear to expand relatively rapidly post speciation; subsequently, and perhaps more gradually, they then decline as species age. We discuss these results with reference to the various models of range-size dynamics that have been proposed
Pink landscapes: 1/f spectra of spatial environmental variability and bird community composition
Temporal and spatial environmental variability are predicted to have reddened spectra that reveal increases in variance with the period or length sampled. However, spectral analyses have seldom been performed on ecological data to determine whether these predictions hold true in the case of spatial environmental variability. For a 50 km long continuous transect of 128 point samples across a heterogeneous cultural landscape in the Czech Republic, both habitat composition and bird species composition decomposed by standard ordination techniques did indeed exhibit reddened spectra.
The values of main ordination axes have relationships between log spectral density and log frequency with slopes close to -1, indicating 1/f, or 'pink' noise type of variability that is characterized by scale invariance. However, when habitat composition was controlled for and only residuals for bird species composition were analysed, the spectra revealed a peak at intermediate frequencies, indicating that population processes that structure bird communities but are not directly related to the structure of the environment might have some typical correlation length. Spatial variability of abundances of individual species was mostly reddened as well, but the degree was positively correlated to their total abundance and niche position (strength of species-habitat association). If 'pink' noise type of variability is as generally typical for spatial environmental variability as for temporal variability, the consequences may be profound for patterns of species diversity on different spatial scales, the form of species-area relationships and the distribution of abundances within species ranges
RCA Satcom: In-orbit experience
The system characteristics of the Satcom batteries and Satcom power system are briefly discussed. Performance of the nickel cadmium 22 cell batteries onboard in parallel with independent redundant charges providing the charge rates is reported. Performance onboard reconditioning with individual cell bypasses with 1 ohm resistors is discussed for the F-1 and F-2 spacecraft
The determinants of the quality of Sales-Marketing Interface in a Multinational Customer Brand Focused Company: The Latin American Branches
Customer evolution and changes in consumers, determine the fact that the quality of the interface between marketing and sales may represent a true competitive advantage for the firm. Building on multidimensional theoretical and empirical models developed in Europe and on social network analysis, the organizational interface between the marketing and sales departments of a multinational high-growth company with operations in Argentina, Uruguay and Paraguay is studied. Both, attitudinal and social network measures of information exchange are used to make operational the nature and quality of the interface and its impact on performance. Results show the existence of a positive relationship of formalization, joint planning, teamwork, trust and information transfer on interface quality, as well as a positive relationship between interface quality and business performance. We conclude that efficient design and organizational management of the exchange network are essential for the successful performance of consumer goods companies that seek to develop distinctive capabilities to adapt to markets that experience vertiginous change
Mapping biodiversity value worldwide: combining higher-taxon richness from different groups
Maps of large-scale biodiversity are urgently needed to guide conservation, and yet complete enumeration of organisms is impractical at present. One indirect approach is to measure richness at higher taxonomic ranks, such as families. The difficulty is how to combine information from different groups on numbers of higher taxa, when these taxa may in effect have been defined in different ways, particularly for more distantly related major groups. In this paper, the regional family richness of terrestrial and freshwater seed plants, amphibians, reptiles and mammals is mapped worldwide by combining: (i) absolute family richness; (ii) proportional family richness; and (iii) proportional family richness weighted for the total species richness in each major group. The assumptions of the three methods and their effects on the results are discussed, although for these data the broad pattern is surprisingly robust with respect to the method of combination. Scores from each of the methods of combining families are used to rank the top five richness hotspots and complementary areas, and hotspots of endemism are mapped by unweighted combination of range-size rarity scores
The Economic Effects of Unions in Latin America: Their Impact on Wages and the Economic Performance of Firms in Uruguay
This study examines the impact of unionization and the level of centralization in bargaining, at the level of the industry or the firm, on wages and on the economic performance of firms within the manufacturing sector in Uruguay, using a panel of establishments for the period 1988 to 1995. In doing so, we control for the degree of exposure to international and regional competition as well as for industry and firm characteristics. The main findings suggest that unionization increases wages and employment and promotes investment due to firms substituting labor by capital. Unions tend to organize in those plants with highest rates of profits, but promote increases in productivity and prevent profitability increases. The mechanism at work seems to be that firms moved to more capital-intensive technologies, hence increasing the rate of growth of labor productivity and reducing that of profitability. Given the negative effect of unionization at the industry level on the rate of growth of profitability of firms, results also suggest that unions tended to organize and to be stronger in those sectors in which extra rents were higher due to monopoly power. The evidence also suggests that firm-level negotiations take into account the interests of both parties, so that enhanced productivity and probably survival were achieved together with lower rates of substitution between labor and capital and/or lower profits.
Unions and Employment in Uruguay
This study examines the impact of unions on wages and employment using data from Uruguay in a period when unions were banned (1973-1984), then legalized with tripartite bargaining (1984-1991) followed by industry-wide or firm-specific bargaining (1992-1997). The relationship between wages and employment shifted significantly across these periods as evidenced by recursive residuals, which show structural shifts in five of six industries, with the shifts coming at the same time as the regime changes. Wages are exogenous to employment before 1985, but not afterwards. Wage elasticity and the employment-output elasticity fell sharply after 1984. Unions significantly raised wages in 1985-1992, but afterwards the change in bargaining structure and increased openness led to concessions. Starting in 1985, workers in unionized industries were less likely to be laid off than workers in nonunion industries.
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