215 research outputs found
Academic Performance and Behavioral Patterns
Identifying the factors that influence academic performance is an essential
part of educational research. Previous studies have documented the importance
of personality traits, class attendance, and social network structure. Because
most of these analyses were based on a single behavioral aspect and/or small
sample sizes, there is currently no quantification of the interplay of these
factors. Here, we study the academic performance among a cohort of 538
undergraduate students forming a single, densely connected social network. Our
work is based on data collected using smartphones, which the students used as
their primary phones for two years. The availability of multi-channel data from
a single population allows us to directly compare the explanatory power of
individual and social characteristics. We find that the most informative
indicators of performance are based on social ties and that network indicators
result in better model performance than individual characteristics (including
both personality and class attendance). We confirm earlier findings that class
attendance is the most important predictor among individual characteristics.
Finally, our results suggest the presence of strong homophily and/or peer
effects among university students
The sperm factor: paternal impact beyond genes
The fact that sperm carry more than the paternal DNA has only been discovered just over a decade ago. With this discovery, the idea that the paternal condition may have direct implications for the fitness of the offspring had to be revisited. While this idea is still highly debated, empirical evidence for paternal effects is accumulating. Male condition not only affects male fertility but also offspring early development and performance later in life. Several factors have been identified as possible carriers of non-genetic information, but we still know little about their origin and function and even less about their causation. I consider four possible non-mutually exclusive adaptive and non-adaptive explanations for the existence of paternal effects in an evolutionary context. In addition, I provide a brief overview of the main non-genetic components found in sperm including DNA methylation, chromatin modifications, RNAs and proteins. I discuss their putative functions and present currently available examples for their role in transferring non-genetic information from the father to the offspring. Finally, I identify some of the most important open questions and present possible future research avenues
Toward mature talent management: beyond shareholder value
Talent management has become one of the most prevalent topics in the field of people management and development for practitioners and academics alike. However, while managers do appear to appreciate the importance of talent management, they often fail to manage it effectively, and the linkages between talent management and organizational performance remain unclear. In this invited feature article, I argue that the failure to effectively manage and develop talent can be traced, in part, to a narrow conceptualization of performance in much thinking on talent management. At an organizational level, this means that performance is generally considered solely in terms of shareholder returns while ignoring other stakeholders. This translates into HR systems that fail to effectively align individuals and organizations in the generation of value. This article foregrounds employees as stakeholders and argues that organizations that are defined by a sense of purpose and that prioritize employees as stakeholders generally have higher levels of alignment between organizational and employee goals with more highly motivated employees and ultimately more sustainable performance. Some implications for research on talent management are developed
A multi-scale analysis of bull sperm methylome revealed both species peculiarities and conserved tissue-specific
peer-reviewedBackground: Spermatozoa have a remarkable epigenome in line with their degree of specialization, their unique
nature and different requirements for successful fertilization. Accordingly, perturbations in the establishment of DNA
methylation patterns during male germ cell differentiation have been associated with infertility in several species.Background: Spermatozoa have a remarkable epigenResults: The quantification of DNA methylation at CCGG sites using luminometric methylation assay (LUMA)
highlighted the undermethylation of bull sperm compared to the sperm of rams, stallions, mice, goats and men.
Total blood cells displayed a similarly high level of methylation in bulls and rams, suggesting that undermethylation
of the bovine genome was specific to sperm. Annotation of CCGG sites in different species revealed no striking bias
in the distribution of genome features targeted by LUMA that could explain undermethylation of bull sperm. To
map DNA methylation at a genome-wide scale, bull sperm was compared with bovine liver, fibroblasts and
monocytes using reduced representation bisulfite sequencing (RRBS) and immunoprecipitation of methylated DNA
followed by microarray hybridization (MeDIP-chip). These two methods exhibited differences in terms of genome
coverage, and consistently, two independent sets of sequences differentially methylated in sperm and somatic cells
were identified for RRBS and MeDIP-chip. Remarkably, in the two sets most of the differentially methylated
sequences were hypomethylated in sperm. In agreement with previous studies in other species, the sequences that
were specifically hypomethylated in bull sperm targeted processes relevant to the germline differentiation program
(piRNA metabolism, meiosis, spermatogenesis) and sperm functions (cell adhesion, fertilization), as well as satellites
and rDNA repeats.
Conclusions: These results highlight the undermethylation of bull spermatozoa when compared with both bovine
somatic cells and the sperm of other mammals, and raise questions regarding the dynamics of DNA methylation in
bovine male germline. Whether sperm undermethylation has potential interactions with structural variation in the
cattle genome may deserve further attention.
While bull semen is widely used in artificial insemination, the literature describing DNA methylation in bull
spermatozoa is still scarce. The purpose of this study was therefore to characterize the bull sperm methylome
relative to both bovine somatic cells and the sperm of other mammals through a multiscale analysis
The diagnosis of male infertility:an analysis of the evidence to support the developments of global WHO guidance. Challenges and future research opportunities
Background: Herein, we describe the consensus guideline methodology, summarize the evidence-based recommendations we provided to the World Health Organization (WHO) for their consideration in the development of global guidance and present a narrative review of the diagnosis of male infertility as related to the eight prioritized (problem or population (P), intervention (I), comparison (C) and outcome(s) (O) (PICO)) questions. Additionally, we discuss the challenges and research gaps identified during the synthesis of this evidence.Objective and Rationale: The aim of this paper is to present an evidence-based approach for the diagnosis of male infertility as related to the eight prioritized PICO questions.Search Methods: Collating the evidence to support providing recommendations involved a collaborative process as developed by WHO, namely: identification of priority questions and critical outcomes; retrieval of up-to-date evidence and existing guidelines; assessment and synthesis of the evidence; and the formulation of draft recommendations to be used for reaching consensus with a wide range of global stakeholders. For each draft recommendation the quality of the supporting evidence was then graded and assessed for consideration during a WHO consensus.Outcomes: Evidence was synthesized and recommendations were drafted to address the diagnosis of male infertility specifically encompassing the following: What is the prevalence of male infertility and what proportion of infertility is attributable to the male? Is it necessary for all infertile men to undergo a thorough evaluation? What is the clinical (ART/non ART) value of traditional semen parameters? What key male lifestyle factors impact on fertility (focusing on obesity, heat and tobacco smoking)? Do supplementary oral antioxidants or herbal therapies significantly influence fertility outcomes for infertile men? What are the evidence-based criteria for genetic screening of infertile men? How does a history of neoplasia and related treatments in the male impact on (his and his partner’s) reproductive health and fertility options? And lastly, what is the impact of varicocele on male fertility and does correction of varicocele improve semen parameters and/or fertility?Wider Implications: This evidence synthesis analysis has been conducted in a manner to be considered for global applicability for the diagnosis of male infertility
Recent developments in genetics and medically assisted reproduction : from research to clinical applications
Two leading European professional societies, the European Society of Human Genetics and the European Society for Human Reproduction and Embryology, have worked together since 2004 to evaluate the impact of fast research advances at the interface of assisted reproduction and genetics, including their application into clinical practice. In September 2016, the expert panel met for the third time. The topics discussed highlighted important issues covering the impacts of expanded carrier screening, direct-to-consumer genetic testing, voiding of the presumed anonymity of gamete donors by advanced genetic testing, advances in the research of genetic causes underlying male and female infertility, utilisation of massively parallel sequencing in preimplantation genetic testing and non-invasive prenatal screening, mitochondrial replacement in human oocytes, and additionally, issues related to cross-generational epigenetic inheritance following IVF and germline genome editing. The resulting paper represents a consensus of both professional societies involved.Peer reviewe
Clinical implications of gait analysis in the rehabilitation of adult patients with "Prader-Willi" Syndrome: a cross-sectional comparative study ("Prader-Willi" Syndrome vs matched obese patients and healthy subjects)
<p>Abstract</p> <p>Background</p> <p>Being severely overweight is a distinctive clinical feature of Prader-Willi Syndrome (PWS). PWS is a complex multisystem disorder, representing the most common form of genetic obesity. The aim of this study was the analysis of the gait pattern of adult subjects with PWS by using three-Dimensional Gait Analysis. The results were compared with those obtained in a group of obese patients and in a group of healthy subjects.</p> <p>Methods</p> <p>Cross-sectional, comparative study: 19 patients with PWS (11 males and 8 females, age: 18–40 years, BMI: 29.3–50.3 kg/m<sup>2</sup>); 14 obese matched patients (5 males and 9 females, age: 18–40 years, BMI: 34.3–45.2 kg/m<sup>2</sup>); 20 healthy subjects (10 males and 10 females, age: 21–41 years, BMI: 19.3–25.4 kg/m<sup>2</sup>). Kinematic and kinetic parameters during walking were assessed by an optoelectronic system and two force platforms.</p> <p>Results</p> <p>PWS adult patients walked slower, had a shorter stride length, a lower cadence and a longer stance phase compared with both matched obese, and healthy subjects. Obese matched patients showed spatio-temporal parameters significantly different from healthy subjects.</p> <p>Furthermore, Range Of Motion (ROM) at knee and ankle, and plantaflexor activity of PWS patients were significantly different between obese and healthy subjects. Obese subjects revealed kinematic and kinetic data similar to healthy subjects.</p> <p>Conclusion</p> <p>PWS subjects had a gait pattern significantly different from obese patients. Despite that, both groups had a similar BMI. We suggest that PWS gait abnormalities may be related to abnormalities in the development of motor skills in childhood, due to precocious obesity. A tailored rehabilitation program in early childhood of PWS patients could prevent gait pattern changes.</p
SP-A binds alpha(1)-antitrypsin in vitro and reduces the association rate constant for neutrophil elastase
BACKGROUND: α1-antitrypsin and surfactant protein-A (SP-A) are major lung defense proteins. With the hypothesis that SP-A could bind α1-antitrypsin, we designed a series of in vitro experiments aimed at investigating the nature and consequences of such an interaction. METHODS AND RESULTS: At an α1-antitrypsin:SP-A molar ratio of 1:1, the interaction resulted in a calcium-dependent decrease of 84.6% in the association rate constant of α1-antitrypsin for neutrophil elastase. The findings were similar when SP-A was coupled with the Z variant of α1-antitrypsin. The carbohydrate recognition domain of SP-A appeared to be a major determinant of the interaction, by recognizing α1-antitrypsin carbohydrate chains. However, binding of SP-A carbohydrate chains to the α1-antitrypsin amino acid backbone and interaction between carbohydrates of both proteins are also possible. Gel filtration chromatography and turnover per inactivation experiments indicated that one part of SP-A binds several molar parts of α1-antitrypsin. CONCLUSION: We conclude that the binding of SP-A to α1-antitrypsin results in a decrease of the inhibition of neutrophil elastase. This interaction could have potential implications in the physiologic regulation of α1-antitrypsin activity, in the pathogenesis of pulmonary emphysema, and in the defense against infectious agents
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