Small mammal assemblages in fragmented shrublands of urban areas of Central Chile

Mediterranean-type ecosystems are one of the most affected environments by habitat loss and fragmentation due to urban development, however only few studies have evaluated the effects of urbanization on the biodiversity of remnant fragments in these ecosystems. This study aims to evaluate the effects of urban development over small mammal assemblages inhabiting isolated forest fragments of an urban area of Chilean Mediterranean zone. We compared abundance and richness of small mammal assemblages of six remnant fragments within an urban matrix, and six fragments similar in area and habitat characteristics with those of urban area, but surrounded by a rural matrix. We found that small mammal assemblages differ considerably among fragments types (urban vs rural), with lack of endemic species from urban fragments and with high proportion of introduced rodents in urban fragments. Furthermore abundance of small mammals was higher in rural than in urban fragments. In urban areas small mammal abundance and richness were not correlated with any of the explanatory variables assessed (woody cover, flora heterogeneity, fragment area, perimeter/area ratio). However in rural fragments small mammal richness was negatively correlated with flora heterogeneity and the abundance of small mammals was positively correlated with perimeter/area ratio. These results reveal important differences within the effects of fragmentation over small mammal assemblages among the two types of fragments assessed. Our findings suggest that in forest fragments isolated by urbanization, larger areas with good quality habitats are not sufficient to maintain native small mammal population.     

Improved population-based probability of developing cancer when direct estimates of the cancer-free population are available

Age-conditional probabilities of developing a first cancer represent the transition from being cancer-free to developing a first cancer. Natural inputs into their calculation are rates of first cancer per person-years alive and cancer-free. However these rates are not readily available because they require information on the cancer-free population. Instead rates of first cancer per person-years alive, calculated using as denominator the mid-year populations, available from census data, can be easily calculated from cancer registry data. Methods have been developed to estimate age-conditional probabilities of developing cancer based on these easily available rates per person-years alive that do not directly account for the cancer-free population. In the last few years models (Merrill et al., Int J Epidemiol 29(2):197-207, 2000; Mariotto et al., SEER Cancer Statistics Review, 2002; Clegg et al., Biometrics 58(3):684-688, 2002; Gigli et al., Stat Methods Med Res 15(3):235-253, 2006, and software (ComPrev:Complete Prevalence Software, Version 1.0, 2005) have been developed that allow estimation of cancer prevalence (DevCan: Probability of Developing or Dying of Cancer Software, Version 6.0, 2005). Estimates of population-based cancer prevalence allows for the estimation of the cancer-free population and consequently of rates per person-years alive and cancer-free. In this paper we present a method that directly estimates the age-conditional probabilities of developing a first cancer using rates per person-years alive and cancer-free obtained from prevalence estimates. We explore conditions when the previous and the new estimators give similar or different values using real data from the Surveillance, Epidemiology and End Results (SEER) program.     

Some new aspects of taxicab correspondence analysis

Correspondence analysis (CA) and nonsymmetric correspondence analysis are based on generalized singular value decomposition, and, in general, they are not equivalent. Taxicab correspondence analysis (TCA) is a \(\hbox {L}_{1}\) variant of CA, and it is based on the generalized taxicab singular value decomposition (GTSVD). Our aim is to study the taxicab variant of nonsymmetric correspondence analysis. We find that for diagonal metric matrices GTSVDs of a given data set are equivalent; from which we deduce the equivalence of TCA and taxicab nonsymmetric correspondence analysis. We also attempt to show that TCA stays as close as possible to the original correspondence matrix without calculating a dissimilarity (or similarity) measure between rows or columns. Further, we discuss some new geometric and distance aspects of TCA.     

Counting people in the data revolution era: challenges and opportunities for population censuses*

Changes in technology, society and individual behaviours are having impressive effects on data production and use. Social networks, sensors and data infrastructure are generating a massive amount of new data (big data, big corpora, linked data, open data, etc.) that are readily available for the analysis of societies. Official statistics too is starting to pay attention to these unofficial data sources, to the aim of using them within the production processes. Despite the potentials of new data for statistical production, so far we can depict two main effects on official statistics, and especially on population censuses. First of all, there is the digitalization of data construction through both new instruments (e.g. web questionnaires) and new means of collection (e.g. tablets). Furthermore, the integration and the scaling-up of data archives is ongoing. This transition from the traditional ‘door-to-door’ census to new census methods, which make an higher use of technology, is not only a technical result, but it reflects the extent to which digital data are changing the routines of production of statistics and their use to gain social knowledge.     

Correspondence Analysis of Cumulative Frequencies Using a Decomposition of Taguchi's Statistic

Taguchi's statistic has long been known to be a more appropriate measure of association for ordinal variables than the Pearson chi-squared statistic. Therefore, there is some advantage in using Taguchi's statistic for performing correspondence analysis when a two-way contingency table consists of one ordinal categorical variable. This article will explore the development of correspondence analysis using a decomposition of Taguchi's statistic.     

The Easterlin Paradox in Italy,or the Paradox in Measuring? Define Happiness Before Investigating It

Social Indicators Research - The Easterlin paradox (Easterlin, in: Paul, Reder (eds) Nations and household in economic growth: essay in honor of Moses Abramovitz, Academic Press, New York, 1974),...     

How Do Students Evaluate Instructors’ Performance? Implication of Teaching Abilities,Physical Attractiveness and Psychological Factors

One instrument regularly seen as a basic resource in assessing pedagogical knowledge and vivid learning in different circumstances is through the method of conducting student assessment appraisal of their instructors. Nevertheless, deciding the nature of instructional abilities requires as rationale and unbiased judgments. The concern is that there are no formal techniques or formulas that would prompt accurate responses from the students. In spite of the contention surrounding students’ rating on instructors, this study aims to investigate how university students in Malaysia would evaluate instructors based on non-instructional factors, such as physical attractiveness and psychological factors, which in turn may affect students’ perceptions towards instructors’ performance. PLS-SEM was appropriated to perform the path modeling analysis. Practical implication is discussed.

     

The analysis of dependence for three ways contingency tables with ordinal variables: A case study of patient satisfaction data

For many questionnaires and surveys in the marketing, business, and health disciplines, items often involve ordinal scales (such as the Likert scale and rating scale) that are associated in sometimes complex ways. Techniques such as classical correspondence analysis provide a simple graphical means of describing the nature of the association. However, the procedure does not allow the researcher to specify how one item may be associated with another, nor does the analysis allow for the ordinal structure of the scales to be reflected. This article presents a graphical approach that can help the researcher to study in depth the complex association of the items and reflect the structure of the items. We will demonstrate the applicability of this approach using data collected from a study that involves identifying major factors that influence the level of patient satisfaction in a Neapolitan hospital.