Urban impacts on tropical island streams: Some key aspects influencing ecosystem response

Improving our understanding of the impacts of urbanization on tropical island streams is critical as urbanization becomes a dominant feature in tropical areas. Although the ??urban stream syndrome?? has been successful in summarizing urban impacts on streams, the response of some island streams is different to that expected. Here we review available information on urban impacts to tropical island streams and describe unique responses to urbanization. We identified three key aspects that play particularly important or unique roles in determining tropical-island stream integrity: biotic response to water pollution, movement barriers along the stream network, and altered geomorphology that results in habitat loss. As expected, water pollution negatively impacts stream ecosystems in tropical islands and in some regions impacts can be severe, as untreated wastewaters are directly discharged into streams. While aquatic insects show the expected responses to pollution, other native fauna (e.g., shrimps and fishes) appear to be less impacted by moderate levels of pollution. Movement barriers along the stream network are especially important as much of the tropical island fauna have diadromous (either amphidromous or catadromous) life histories. Most native freshwater mollusks, shrimps, and fishes inhabiting tropical islands are diadromous and depend on unimpeded connections between freshwater and marine environments to complete their life cycles. The presence of these species in urban streams is best explained by longitudinal connectivity rather than by the degree of urban impact. Finally, in streams that remain connected to marine environments, the presence of native shrimps and fishes is strongly related to the physical habitat. Fish assemblages in channelized and severely altered stream reaches are almost completely devoid of native fauna and tend to be dominated by non-native species. In contrast, relatively diverse shrimp and fish assemblages can be found in reaches that retain their physical habitat complexity, even when they are impacted by urbanization. Our understanding of urban impacts on tropical island streams remains limited. However, the identification of key aspects can help us better understand urban impacts on streams in tropical islands, and best focus our management and research efforts to protect these unique ecosystems.     

Improving the detection of unusual observations in high‐dimensional settings

Multivariate control charts are used to monitor stochastic processes for changes and unusual observations. Hotelling's T² statistic is calculated for each new observation and an out‐of‐control signal is issued if it goes beyond the control limits. However, this classical approach becomes unreliable as the number of variables p approaches the number of observations n, and impossible when p exceeds n. In this paper, we devise an improvement to the monitoring procedure in high‐dimensional settings. We regularise the covariance matrix to estimate the baseline parameter and incorporate a leave‐one‐out re‐sampling approach to estimate the empirical distribution of future observations. An extensive simulation study demonstrates that the new method outperforms the classical Hotelling T² approach in power, and maintains appropriate false positive rates. We demonstrate the utility of the method using a set of quality control samples collected to monitor a gas chromatography–mass spectrometry apparatus over a period of 67 days.     

An Integrative View of the Institutional Repositories in Hong Kong: Strategies and Challenges

This paper reports on the developmental strategies, challenges and directions of the institutional repositories of the higher educational institutions in Hong Kong. The study integrates the size, content, full text and public accessibility of these repositories. The paper also compares archived output with research output as registered by the Hong Kong University Grants Committee. Percentages of archived work are low for journal and conference papers, but moderate for graduate theses. These deposit rates reflect the differing institutional policies. In recognizing these challenges, the Hong Kong Open Access Committee has been formed to address regional issues in knowledge sharing.     

Estimating a sensitive proportion through randomized response procedures based on auxiliary information

Randomized response techniques are widely employed in surveys dealing with sensitive questions to ensure interviewee anonymity and reduce nonrespondents rates and biased responses. Since Warner’s (J Am Stat Assoc 60:63–69, 1965) pioneering work, many ingenious devices have been suggested to increase respondent’s privacy protection and to better estimate the proportion of people, π _A , bearing a sensitive attribute. In spite of the massive use of auxiliary information in the estimation of non-sensitive parameters, very few attempts have been made to improve randomization strategy performance when auxiliary variables are available. Moving from Zaizai’s (Model Assist Stat Appl 1:125–130, 2006) recent work, in this paper we provide a class of estimators for π _A , for a generic randomization scheme, when the mean of a supplementary non-sensitive variable is known. The minimum attainable variance bound of the class is obtained and the best estimator is also identified. We prove that the best estimator acts as a regression-type estimator which is at least as efficient as the corresponding estimator evaluated without allowing for the auxiliary variable. The general results are then applied to Warner and Simmons’ model.     

Fugitive slaves and Christian evangelism in French West Africa: a protestant mission in late nineteenth-century Senegal

This article examines a Protestant mission in late nineteenth-century Senegal that served as a refuge for runaway slaves in French West Africa. While slavery in Africa has been understood as benign and the end of slavery as a process of ‘renegotiation’ rather than a struggle for freedom, evidence from the mission shows the complicated and personal nature of emancipation for escaped slaves who joined religious communities. By analyzing the mission’s annual report, this essay sheds light on the lives of individual men and women who fled to the colonial capital and adopted strategies to secure their status as freepersons.     

Competing Priorities: Partner-Specific Relationship Characteristics and Motives for Condom Use Among At-Risk Young Adults

Condoms protect against human immunodeficiency virus (HIV)/sexually transmitted infections (STIs) and unintended pregnancy and are essential to sexual health efforts targeting young adults, who are disproportionately affected by both outcomes. Understanding condom use motives is critical to increasing condom use. Research in this area is limited, particularly regarding the roles of partners and relationship factors. Using a longitudinal sample of 441 young adults and 684 reported partnerships we examined associations between relationship factors and condom use motives (pregnancy prevention, disease prevention, or dual protection). Simultaneous multilevel models identified variables associated with motives; level-specific models identified the levels (individual, partnership, time) variables impacted motives. Participants reported choosing condoms for pregnancy prevention, disease prevention, and dual protection in 51%, 17%, and 33% of partnerships, respectively. Partner-specific factors varied, to a differing degree, across the three levels. Seven variables (duration, condom self-efficacy, commitment, sexual decision-making, power, and vulnerability to harm [HIV/STIs] and pregnancy) distinguished condom use motives. The level of this association varied but was most pronounced at the partner and individual levels. Researchers and practitioners should consider the impact of both individual- and partner-level factors on condom use motives, in both research and sexual health programs.     

An empirical assessment of writing and research proficiency in HBCU social work students

ABSTRACT

Lack of proficiency in writing and research among social work students has increasingly concerned social work educators and practitioners. Given the significance of written communication with clients and emphasis on evidence-based practice in the field of social work, it is critical to assess students’ competence in both writing and research. However, deficit-based approaches to assessing writing and research competence have disadvantaged students at historically black colleges and universities (HBCUs). This pilot study aims to assess writing and research proficiency of HBCU master’s of social work (MSW) students through empirical analysis of their capstone papers and surveys from educators to provide implications for developing a writing and research manual for social work programs at HBCUs. Ten capstone papers were randomly selected and qualitatively analyzed; nine faculty and one field supervisor completed the survey, and their respondents were analyzed using cross-case analysis. Analyses of the capstone papers identified two themes for writing and research domains, respectively: (1) weakness in developing statements and lack of knowledge of writing style and (2) plagiarism and lack of understanding of research structure. Moreover, analyses of the surveys revealed four themes regarding assessment of writing and research skills among students struggling with basic writing mechanics, indicating that HBCU MSW students may have potential and capacity for learning, as evidenced by their ideas and critical thinking skills. These findings suggest both teaching- and research-oriented programs could employ the proposed writing and research assessment manual, as well as a writing and research lab/center for improving writing and research skills among their students.