An Investigation of Same- Versus Cross-Gender Matching for Boys in Formal School-Based Mentoring Programs

Although assigned mentoring relationships have typically involved same-gender matches, a growing number of programs, particularly those in schools, have begun pairing female mentors with male mentees. This practice stems, in large part, from the relative dearth of male mentors and programs’ efforts to increase the availability of youth mentoring to young males on waiting lists. We drew on secondary data from the two largest random assignment evaluations of school-based mentoring programs, the Department of Education's Student Mentoring Program and Big Brothers Big Sisters of America's School-based Mentoring, to explore the characteristics and effects of same- versus cross-gender mentoring relationships for male mentees. Our sample included 1,513 male youth from the respective programs. With only a few exceptions, male youth in same- versus cross-gender mentoring relationships experienced similar relationship processes and outcomes. Implications for research and practice are discussed along with limitations including the nonexperimental design of the study and unmeasured effects of selection bias.     

Pygmalion in the Program: The Role of Teenage Peer Mentors' Attitudes in Shaping Their Mentees' Outcomes

Cross-age peer mentoring programs, in which teenagers mentor younger children, have proliferated in recent years, yet there is disagreement about the effectiveness of such programs. This study tested whether teen mentors' attitudes about children interact with their mentees' characteristics to moderate outcomes of cross-age peer mentoring. The sample included 221 high school volunteers, 205 mentees, and 182 control group youth. Latent profile analyses yielded two profiles of students who were labeled “academically connected” or “disconnected.” Analyses revealed that the academically disconnected mentees who were paired with mentors holding relatively positive attitudes toward youth were more emotionally engaged in the mentoring relationship (than disconnected mentees with more negative mentors) and, subsequently, reported stronger relationships with their teachers at year's end (than did the similarly disconnected children in the control group). Conversely, there was evidence of iatrogenic effects of matching negative mentors with academically connected mentees. Implications for mentor selection and training are discussed.     

Anthropometric Characteristics,Physical Fitness and Motor Coordination of 9 to 11 Year Old Children Participating in a Wide Range of Sports

ObjectivesThe aim of this study was to investigate to what extent 9 to 11 year old children participating in a specific sport already exhibit a specific anthropometric, physical fitness and motor coordination profile, in line with the requirements of that particular sport. In addition, the profiles in children with a different training volume were compared and possible differences in training hours per week between children from a low, moderate, and high level of physical fitness and motor coordination were investigated.DiscussionThe study showed that in general, children at a young age do not exhibit sport-specific characteristics, except in children with a high training volume. It is possible that on the one hand, children have not spent enough time yet in their sport to develop sport-specific qualities. On the other hand, it could be possible that they do not take individual qualities into account when choosing a sport.     

Model selection in ecology and evolution

Recently, researchers in several areas of ecology and evolution have begun to change the way in which they analyze data and make biological inferences. Rather than the traditional null hypothesis testing approach, they have adopted an approach called model selection, in which several competing hypotheses are simultaneously confronted with data. Model selection can be used to identify a single best model, thus lending support to one particular hypothesis, or it can be used to make inferences based on weighted support from a complete set of competing models. Model selection is widely accepted and well developed in certain fields, most notably in molecular systematics and mark-recapture analysis. However, it is now gaining support in several other areas, from molecular evolution to landscape ecology. Here, we outline the steps of model selection and highlight several ways that it is now being implemented. By adopting this approach, researchers in ecology and evolution will find a valuable alternative to traditional null hypothesis testing, especially when more than one hypothesis is plausible.     

Consistency of hand preference across low-level and high-level tasks in capuchin monkeys (Cebus apella)

Numerous studies investigating behavioral lateralization in capuchins have been published. Although some research groups have reported a population-level hand preference, other researchers have argued that capuchins do not show hand preference at the population level. As task complexity influences the expression of handedness in other primate species, the purpose of this study was to collect hand preference data across a variety of high- and low-level tasks to evaluate how task complexity influences the expression of hand preference in capuchins. We tested eleven captive brown capuchin monkeys (Cebus apella) to determine if they show consistent hand preferences across multiple high- and low-level tasks. Capuchins were expected to display high intertask consistency across the high-level tasks but not the low-level tasks. Although most individuals showed significant hand preferences for each task, only two of the high-level tasks that involved similar hand motions were significantly positively correlated, indicating consistency of hand preference across these tasks only. None of the tasks elicited a group-level hand preference. High-level tasks elicited a greater strength of hand preference than did low-level tasks. No sex differences were found for the direction or strength of hand preference for any task. These results contribute to the growing database of primate laterality and provide additional evidence that capuchins do not display group-level hand preferences.     

Ongoing DNA synthesis continues in young human diploid cells (HDC) fused to senescent HDC, but entry into S phase is inhibited

Previous experiments have shown that when young human diploid cells (HDC) were fused to senescent HDC, neither nucleus synthesized DNA. This paper demonstrates that when young HDC are in S phase at the time of fusion to senescent HDC, they do make DNA in heterodikaryons; therefore, ongoing DNA synthesis is not inhibited by senescent cells. On the other hand, entry into S phase is inhibited: young HDC nuclei in G1 phase do not make DNA in heterodikaryons with senescent HDC.     

Measuring Software Timing Errors in the Presentation of Visual Stimuli in Cognitive Neuroscience Experiments

Because of the features provided by an abundance of specialized experimental software packages, personal computers have become prominent and powerful tools in cognitive research. Most of these programs have mechanisms to control the precision and accuracy with which visual stimuli are presented as well as the response times. However, external factors, often related to the technology used to display the visual information, can have a noticeable impact on the actual performance and may be easily overlooked by researchers. The aim of this study is to measure the precision and accuracy of the timing mechanisms of some of the most popular software packages used in a typical laboratory scenario in order to assess whether presentation times configured by researchers do not differ from measured times more than what is expected due to the hardware limitations. Despite the apparent precision and accuracy of the results, important issues related to timing setups in the presentation of visual stimuli were found, and they should be taken into account by researchers in their experiments.     

BraX-Ray: An X-Ray of the Brazilian Computer Science Graduate Programs

Research productivity assessment is increasingly relevant for allocation of research funds. On one hand, this assessment is challenging because it involves both qualitative and quantitative analysis of several characteristics, most of them subjective in nature. On the other hand, current tools and academic social networks make bibliometric data web-available to everyone for free. Those tools, especially when combined with other data, are able to create a rich environment from which information on research productivity can be extracted. In this context, our work aims at characterizing the Brazilian Computer Science graduate programs and the relationship among themselves. We (i) present views of the programs from different perspectives, (ii) rank the programs according to each perspective and a combination of them, (iii) show correlation between assessment metrics, (iv) discuss how programs relate to another, and (v) infer aspects that boost programs'' research productivity. The results indicate that programs with a higher insertion in the coauthorship network topology also possess a higher research productivity between 2004 and 2009.     

Translation of Questionnaires Measuring Health Related Quality of Life Is Not Standardized: A Literature Based Research Study

IntroductionThere is growing awareness of the need to explore patient reported outcomes in clinical trials. In the Scandinavian Surgical Outcomes Research Group we are conducting several clinical trials in cooperation between Danish and Swedish surgical researchers, and we use questionnaires aimed at patients from both countries. In relation to this and similar international cooperation, the validity and reliability of translated questionnaires are central aspects.ResultsWe retrieved 187 studies and out of theses we included 52 studies. The psychometric properties of the translated versions were validated using different tests. The focus was on internal validity (96%), reliability (67%) criterion validity (81%), and construct validity (62%). For internal validity Cronbach''s alpha was used in 94% of the studies.ConclusionsThis study shows that there seems to be a consensus regarding the translation process (especially for internal validity) although most researchers did not use a translation guide. Moreover, we recommended that clinical researchers should consider three steps covering the process of translation, the qualitative validation as well as the quantitative validation.     

Selective molecular recognition in amyloid growth and transmission and cross-species barriers

Mutual conformational selection and population shift followed by minor induced-fit optimization is the key mechanism in biomolecular recognition, and monomers and small oligomers binding to amyloid seeds in fibril growth is a molecular recognition event. Here, we describe amyloid aggregation, preferred species, cross-species barriers and transmission within the broad framework of molecular recognition. Cross-seeding of amyloid species is governed by conformational selection of compatible (complementary) states. If the dominant conformations of two species are similar, they can cross-seed each other; on the other hand, if they are sufficiently different, they will grow into different fibrils, reflecting species barriers. Such a scenario has recently been observed for the tau protein, which has four repeats. While a construct consisting of repeats 1, 3 and 4 can serve as a seed for the entire four-repeat tau segment, the inverse does not hold. On the other hand, the tau protein repeats with the characteristic U-turn shape can cross-seed Alzheimer's amyloid β and, similarly, the islet amyloid polypeptide. Within this framework, we suggest that the so-called "central dogma" of amyloid formation, where aggregation takes place through nonspecific backbone hydrogen bonding interactions, which are common to all peptides and proteins, is a simple reflection of the heterogeneous, polymorphic free-energy landscape of amyloid species. Here, we review available data and make some propositions addressing this key problem. In particular, we argue that recent theoretical and experimental observations support the key role of selective molecular recognition in amyloidosis and in determining cross-species barriers and transmission.     

ADDICTION AND AUTONOMY: CAN ADDICTED PEOPLE CONSENT TO THE PRESCRIPTION OF THEIR DRUG OF ADDICTION?

It is often claimed that the autonomy of heroin addicts is compromised when they are choosing between taking their drug of addiction and abstaining. This is the basis of claims that they are incompetent to give consent to be prescribed heroin. We reject these claims on a number of empirical and theoretical grounds. First we argue that addicts are likely to be sober, and thus capable of rational thought, when approaching researchers to participate in research. We reject behavioural evidence purported to establish that addicts lack autonomy. We present an argument that extrinsic forces must be irresistible in order to make a choice non-autonomous. We argue that heroin does not present such an irresistible force. We make a case that drug-oriented desires are strong regular appetitive desires, which do not compromise consent. Finally we argue that an addict's apparent desire to engage in a harmful act cannot be construed as evidence of irrational or compulsive thought. On these arguments, a sober heroin addict must be considered competent, autonomous and capable of giving consent. More generally, any argument against legalisation of drugs or supporting infringement of the liberty of those desiring to take drugs of addiction must be based on considerations of harm and paternalism, and not on false claims that addicts lack freedom of the will.     

The Unusual X-Form DNA in Oligodeoxynucleotides: Dependence of Stability on the Base Sequence and Length

Abstract

X-form is an unusual double helix of DNA adopted by poly(dA-dT) or (dT-dA)₄ at high concentrations of CsF. On the other hand, poly(dA).poly(dT), (dA-dT)₄ and most other DNAs do not adopt this conformer. Here we demonstrate that the X-form is strongly destabilized by GC pairs or even minute perturbations of the alternating pyrimidine- purine sequence. For example, the 30-mer d(TATAAT)₅, containing five tandem repeats of the Pribnow box, fails to isomerize into the X-form. After (dT-dA)₄, the 16-mer (dT- dA)_g is shown to be the second most predisposed oligodeoxynucleotide in the (dT-dA)., series to isomerize into the X-form while the duplex lengths corresponding to n=3,5,6,7,9,12 and 20 make the X-form unstable even in the strictly alternating (dT-dA)., sequence. Consequently, the (dT-dA)., duplex length is also a crucial factor of the X-form stability on the oligodeoxynucleotide level. We discuss a possibility that the X-form is a solution counterpart of the D-form adopted in dehydrated poly(dA-dT) fibers because properties of these two conformers are remarkably similar in many respects.     

Integrating research and education at research-extensive universities with research-intensive communities

Although the Boyer Commission (1998) lamented the lack of research opportunities for all undergraduates at research-extensive universities, it did not provide a feasible solution consistent with the mandate for faculty to maintain sustainable physiology research programs. The costs associated with one-on-one mentoring, and the lack of a sufficient number of faculty members to give intensive attention to undergraduate researchers, make one-on-one mentoring impractical. We therefore developed and implemented the "research-intensive community" model with the aim of aligning diverse goals of participants while simultaneously optimizing research productivity. The fundamental organizational unit is a team consisting of one graduate student and three undergraduates from different majors, supervised by a faculty member. Undergraduate workshops, Graduate Leadership Forums, and computer-mediated communication provide an infrastructure to optimize programmatic efficiency and sustain a multilevel, interdisciplinary community of scholars dedicated to research. While the model radically increases the number of undergraduates that can be supported by a single faculty member, the inherent resilience and scalability of the resulting complex adaptive system enables a research-intensive community program to evolve and grow.     

Palaeoecology of cave bears as evidenced by dental wear analysis: a review of methods and recent findings

Abstract

The study of dental wear was first used years ago to infer the palaeoecology of fossil mammals and in particular their diet. Results depend predominantly on the scale of the analysis used. Analyses of dental macrowear, mesowear or microwear do not provide the same type of dietary information, be it about the seasonal, annual or lifetime diet. This contribution focuses on emblematic species, cave bears (Ursidae), in particular Ursus spelaeus spelaeus. Methods used by previous researchers to infer their dietary preferences and thus their palaeoecology are reviewed and compared. This review is complemented by an analysis of several specimens of cave bears from the Goyet cave in Belgium, using dental microwear texture analysis (DMTA), a methodology widely applied for reconstructing palaeodiets. Three main conclusions are drawn here: (1) DMTA is the method that provides the most precise palaeobiological inferences; (2) during the pre-dormancy period, cave bears show dietary flexibility; (3) dental wear alone might be not sufficient to provide a complete reconstruction of the cave bear palaeodiet.     

Ethical and epistemological insights: a case study of participatory action research with young people

Debates over how to determine age of consent for youth to participate in research feature prominently in the practice of researchers, research ethics boards (REBs), and community decision makers working with youth. In particular, tensions can arise over how the ethical principles of beneficence, autonomy, and justice are interpreted and applied in research involving young people. We discuss our experiences obtaining ethical approval to conduct a participatory action research project involving youth and the differences of opinion we encountered regarding underage youth's capability to make informed consent. We suggest that researchers, REBs, and community decision makers all share a responsibility to conduct proactive outreach to youth participants, so that they are adequately informed of their rights related to research.     

Making inferences about speciation using sophisticated statistical genetics methods: look before you leap

Understanding speciation is a fundamental aim of evolutionary biology and a very challenging one. Speciation can be viewed as the dynamics of genetic differentiation between populations resulting in substantial reproductive isolation (Gavrilets 2003). It was generally accepted that very small levels of migration prevent genetic differentiation among populations and, therefore, speciation. However, recent theoretical work showed that sympatric speciation is possible (Gavrilets 2003). Nevertheless, providing empirical evidence that gene flow occurred during speciation is challenging because several gene flow scenarios can explain observed patterns of genetic differentiation. Positive migration rate estimates alone do not prove ongoing gene flow during divergence. We also need to know whether migration took place before, during or after speciation. There is no statistical method specifically aimed at estimating gene flow timing, but several studies used the isolation with migration model (Hey & Nielsen 2004, 2007; Hey 2010b) to estimate this parameter and make inferences about speciation scenarios. It is tempting to use statistical methods to estimate important evolutionary parameters even if they do not appear explicitly in the inference model. Nevertheless, before doing so, we need to determine whether they can provide reliable results. In this issue of Molecular Ecology, Strasburg and Rieseberg (2011) present a simulation study that examines the degree to which gene flow timing estimates obtained from IMa2 (Hey 2010b) can be used to make inferences about speciation mode. Their results are sobering; gene flow timing estimates obtained in this way are not reliable and cannot be used to unequivocally establish if gene flow was ongoing during speciation.     

The Manipulation of Micro-organisms for the Production of Secondary Metabolites

Abstract

Toxicity testing with animals is expensive, ethically controversial, and not always predictive of the human response. Cell-based assays are regarded as an alternative. However, conventional two-dimensional cell cultures do not reproduce the tissue architecture in vivo, and do not forecast organ-specific toxicity. On the other hand, three-dimensional cultures emulate the biochemistry and mechanics of the microenvironment in tissues more closely. Therefore, they address the limitations of both animals and two-dimensional cultures, and provide more accurate data on the effects of short- and long-term exposure to toxicants. We provide an up-to-date overview on the use of three-dimensional cell cultures in toxicology. We anticipate that three-dimensional cultures will become invaluable to accomplish the 3R agenda (refinement, reduction, and replacement) for animal-based toxicity testing and will play a major role for the Registration, Evaluation and Authorisation of Chemicals in the European Union (REACH legislation).     

"They See Us as Resource": The Role of a Community-Based Youth Center in Supporting the Academic Lives of Low-Income Chinese American Youth

Based on a 15-week ethnographic-based research, this article examines the role of a community-based youth center in supporting the academic lives of Chinese American youth from low-income families in an east coast city I call "Harborview." This study demonstrates the significant role that community-based organizations play for low-income immigrant youth in providing them with social capital. This study also challenges the portrayal of Asian Americans as model minorities who do not face any barriers.  [Asian American education, community-based organizations, out-of-school-time programs, social capital]     

Contemporary gene flow between “paired” silver (<Emphasis Type="Italic">Ichthyomyzon unicuspis</Emphasis>) and northern brook (<Emphasis Type="Italic">I. fossor</Emphasis>) lampreys: implications for conservation

In most lamprey genera, “paired” species exist in which the larvae are morphologically similar or indistinguishable but, following metamorphosis, one species becomes parasitic while the other bypasses the adult feeding phase and rapidly becomes sexually mature. Since DNA barcoding and similar studies using short segments of the mitochondrial genome do not provide sufficient resolution to distinguish between recent divergence and a lack thereof, the current study examined the relationship between the parasitic silver lamprey (Ichthyomyzon unicuspis) and nonparasitic northern brook lamprey (I. fossor) using up to 10,230 bp from the mitochondrial genome to make phylogenetic inferences and mitochondrial restriction fragment length polymorphism (RFLP) and microsatellite markers to test for significant differences in allele frequencies. We found that silver and northern brook lampreys are not reciprocally monophyletic; two lineages were observed but each occurred within both species. There also were no significant range-wide differences in RFLP haplotype or microsatellite allele frequencies between the species, nor were there significant differences where they occurred sympatrically within the Lake Huron basin. Significant genetic differentiation was found only within the Lake Michigan basin where the results were potentially confounded by geographic separation. Our results thus support suggestions that silver and northern brook lampreys represent ecotypes of a single species since, where they are sympatric, they appear to be experiencing ongoing gene flow. However, alternative life history strategies can be important for a species’ long-term persistence, and critical data are needed to decide whether these two feeding types should be managed as a single unit.     

Morbidity Rate Prediction of Dengue Hemorrhagic Fever (DHF) Using the Support Vector Machine and the Aedes aegypti Infection Rate in Similar Climates and Geographical Areas

BackgroundIn the past few decades, several researchers have proposed highly accurate prediction models that have typically relied on climate parameters. However, climate factors can be unreliable and can lower the effectiveness of prediction when they are applied in locations where climate factors do not differ significantly. The purpose of this study was to improve a dengue surveillance system in areas with similar climate by exploiting the infection rate in the Aedes aegypti mosquito and using the support vector machine (SVM) technique for forecasting the dengue morbidity rate.ConclusionsThe infection rates of the Ae. aegypti female mosquitoes and larvae improved the morbidity rate forecasting efficiency better than the climate parameters used in classical frameworks. We demonstrated that the SVM-R-based model has high generalization performance and obtained the highest prediction performance compared to classical models as measured by the accuracy, sensitivity, specificity, and mean absolute error (MAE).