A small sample estimator for a polynomial regression with errors in the variables

An adjusted least squares estimator, introduced by Cheng and Schneeweiss for consistently estimating a polynomial regression of any degree with errors in the variables, is modified such that it shows good results in small samples without losing its asymptotic properties for large samples. Simulation studies corroborate the theoretical findings.     

Optimality of the quasi-score estimator in a mean–variance model with applications to measurement error models

We consider a regression of y$y$ on x$x$ given by a pair of mean and variance functions with a parameter vector θ$\theta$ to be estimated that also appears in the distribution of the regressor variable x$x$. The estimation of θ$\theta$ is based on an extended quasi-score (QS) function. We show that the QS estimator is optimal within a wide class of estimators based on linear-in-y$y$ unbiased estimating functions. Of special interest is the case where the distribution of x$x$ depends only on a subvector α$\alpha$ of θ$\theta$, which may be considered a nuisance parameter. In general, α$\alpha$ must be estimated simultaneously together with the rest of θ$\theta$, but there are cases where α$\alpha$ can be pre-estimated. A major application of this model is the classical measurement error model, where the corrected score (CS) estimator is an alternative to the QS estimator. We derive conditions under which the QS estimator is strictly more efficient than the CS estimator.     

The influence of small urban parks characteristics on bird diversity: A case study of Petaling Jaya,Malaysia

The capacity of small urban park to serve as urban habitats are rarely explored. This study analyses the characteristics of small urban parks and their potential to support urban biodiversity and ecological functions. Nine small urban parks were studied in Malaysia in August and September 2014 using the combined field survey method of structured observation and field measurements. The measured variables were divided into three broad categories of physical characteristics, species richness and human factors. Bird species richness and abundance were used as the indicators for assessing biodiversity. Pearson correlations and multiple regressions were conducted to analyse the relationships between variables and to identify which variables had a significant effect on bird species richness and abundance. The results demonstrated that park area and vegetation variables ( e.g. the percentage of tree canopy cover, open grass/ground, native-exotic plants) are the important predictors of bird species richness and abundance. The percentage of canopy covers (negative relation) and park area (positive relation) are the best predictors of bird species richness in small urban parks. Meanwhile, the best predictors for bird abundance are the percentage of canopy covers (negative relation) and native vegetation species (positive relation). Human activities and park surroundings have a marginal effect on the presence of bird species in small parks. Based on the findings, we provide two general recommendations that could probably increase bird diversity in small urban parks: (1) the park development and management plan should incorporate a social-ecological approach that can benefit both city-dwellers and bird species, and (2) findings from the study should be used to rethink the planting design and composition of especially newly established small urban parks.     

Vernetzte Zusammenarbeit erfolgreich gestalten – eine Analyse der Relevanz sozialer Fertigkeiten der Mitglieder in Gesundheitsnetzwerken

Due to recent strategic network building among health care partners a more differentiated discussion about the crucial structural and the personal success factors for network building and cooperation is needed. On that note, research has repeatedly emphasized the importance of the network agents’ individual soft skills. At the same time the empirical insights into this research topic are still scarce and the assumed interrelation between an agent’s individual repertoire of skills and his influence on the collaboration remain hypothetical so far. In the present paper we use the construct of so-called “political skills” to empirically test the impact of these skills on how they will contribute to the network members’ success within the cooperation. Using social network analysis the interaction structures between members in a doctors’ network (N = 37) are mapped and related to the individual level of political skills. It can be shown that primarily the dimension “networking ability” contributes to a beneficial role within the cooperation in terms of high prestige and high engagement as perceived by the other network members. In addition, members who scored high on that dimension are more likely to obtain benefits on an individual level (gaining new patients) as well as on a group level (identification with the network). One core implication that derives from the study’s results is the necessity to focus not only on strategic aspects with regard to building and designing health care networks, but also to develop and to foster personal soft-skills.     

On the manipulability of approval voting and related scoring rules

We characterize all preference profiles at which the approval (voting) rule is manipulable, under three extensions of preferences to sets of candidates: by comparison of worst candidates, best candidates, or by comparison based on stochastic dominance. We perform a similar exercise for k-approval rules, where voters approve of a fixed number k of candidates. These results can be used to compare (k-)approval rules with respect to their manipulability. Analytical results are obtained for the case of two voters, specifically, the values of k for which the k-approval rule is minimally manipulable—has the smallest number of manipulable preference profiles—under the various preference extensions are determined. For the number of voters going to infinity, an asymptotic result is that the k-approval rule with k around half the number of candidates is minimally manipulable among all scoring rules. Further results are obtained by simulation and indicate that k-approval rules may improve on the approval rule as far as manipulability is concerned.     

Temporal aspects of increases in eye-neck activation levels during visually deficient near work

In an experimental study two levels of oculomotor load were induced via optical trial lenses. Trapezius muscle activity was measured with bipolar surface electromyography and normalized to a submaximal contraction. Sixty-six subjects with a median age of 36 (range 19-47, std 8) viewed a black and white Gabor grating (5 c/deg) for two 7-min periods monocularly through a 0 D lens or binocularly through -3.5 D lenses. The effect of time was separately regressed to EMG in two different subgroups of responders: a High-Oculomotor-Load (HOL) and a Low-Oculomotor-Load (LOL) group. A linear regression model was fitted on group level with exposure time on the x-axis and normalized trapezius muscle EMG (%RVE) on the y-axis. The slope coefficient was significantly positive in the -D blur condition for only the HOL subgroup of responders: 0.926 + Time(min 1-7) × 0.088 (p = 0.002, r(2)=0.865). There was no obvious sign of this activity to level off or to stabilize. These results suggest that professional information technology users that are exposed to a high level of oculomotor load, during extended times, are at an increased risk of exhibiting an increased trap.m. activity.     

Modeling human-bed interaction: the predictive value of anthropometric models in choosing the correct bed support

The sleep system (i.e. the combination of mattress and bed base) is an important factor of the sleep environment since it allows physical recuperation during sleep by providing proper body support. However, various factors influence the interaction between the human body and the sleep system. Contributing factors include body dimensions, distribution of body weight and stiffness of the sleep system across the mattress surface. During the past decade, the rise of several new bedding technologies has made it increasingly difficult for the consumer to select a proper sleep system. Therefore, this study presents a method to model human-bed interaction in order to objectively predict the ideal sleep system for a particular individual. The proposed method combines a personalized anthropometric model with standardized load-deflection characteristics of mattress and bed base. Results for lateral sleep positions show a root mean square deviation of 11.9 ± 6.1 mm between modeled spine shapes and validation shapes, derived from 3D surface scans of the back surface. The method showed to be a reliable tool to individually identify the sleep system providing superior support from a variety of possible mattress-bed base combinations.     

Daily Dynamics of Adolescent Mood and Identity

Important linkages between daily mood and identity formation have been theorized, but have not been empirically tested as of yet. This study provided a first examination of these linkages within individuals (N = 392; 55.1% boys; M_age at T1 = 13.24, SD = 0.44) across 15 series of 5 days distributed over 5 years. Results revealed negative within‐time associations of educational and relational commitment with negative mood. Negative mood was positively associated with educational in‐depth exploration and educational and interpersonal reconsideration. Additionally, there were some cross‐lagged effects suggesting that identity and mood mutually affect one another across days. These results contribute to the growing knowledge on how identity unfolds in everyday life by revealing important associations with daily mood.     

Working with social complexity in a neoliberal society: challenges for social work in Estonia

This article deals with Estonian social workers' perspectives on the fundamentals of the social work profession in a society where radical social, political, and economic changes have occurred within a very short period of time. Estonia typically figures as a model country, sometimes as a positive model, sometimes as a negative one, but according to most commentators, Estonia has pursued social and economic transformations in a particularly dramatic way. Social workers have recognized that radical changes have created new types of problems and social work should deal with vulnerable people and families under uncertain and unforeseeable conditions. Estonia is a challenging example to understand social work in the context of a neoliberal market society. It is therefore necessary to find out what the new challenges for the development of social work as a profession are. This article explores a ‘direction’ toward which social work in Estonia is developing, focusing mainly on the influence of the Estonian political context. The results of the research are relevant to the entire social work profession, insomuch as they address questions about the essence of social work and the ethical principles of the social work profession in society and how they can be strongly influenced by neoliberal thinking and increasing complexity.     

Live audience responses to live televised election debates: time series analysis of issue salience and party salience on audience behavior

Televised political debates are the platforms for party leaders to outline their party's political programs and to attack those of their political opponents. At the same time journalists who moderate the debates are testing the party leaders’ ability to clearly outline and defend their programs. Television audiences of election debates evaluate these party leaders and political parties based on their television performances. Prior to the social media era, viewers’ evaluations were collected through phone surveys or web questionnaires. Nowadays viewers share their opinions in real-time on social media. Particularly Twitter is used in the Netherlands as the platform to share these opinions. In this study tweets produced by the audiences of five different televised debates that took place during the campaign for the Dutch 2012 parliamentary elections are analyzed in terms of tweeting about politicians and parties as well as political issues, as well as the content of the debates. This allowed us, using time series analysis, to test the relation between issue salience in debates and issue salience of the audience on Twitter. The issues of ‘Employment and income’ and ‘Europe’ were the most tweeted about, roughly aligning with the attention these issues received in televised debates. Findings further show there are consistent audience reactions to issues discussed in the debates: issues of ‘Housing’, ‘Care for the needy', and ‘Europe’ showing the strongest effects. However, candidates and parties are not explicitly associated by people active on Twitter when certain political issues are being debated on TV.