2,812 research outputs found
Teacher Leader Administrators: Part 3 Of A Symposium On Teachers As Leaders
In this latest continuation of our multipart symposium on teacher leadership, we examine what happens when self-defined teacher leaders become school administrators. Do teacher leaders who become administrators maintain a teacher identity? Can they remain committed to their vision of teacher leadership when they take on the normative requirements and responsibilities of school administration? Through a conversation with three teachers leaders, we explore the rewards and trials of teaching, the choice to become teacher leaders and then administrators, and the unique challenges that face administrators who deeply value the professional, political, and collaborative work of teachers
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Syntactic Variation
This chapter considers the syntax of dialects of English from a view that incorporates issues in dialectal variation and syntactic theory. Variation in dialects of languages such as Italian, German, Dutch, and Flemish has been analyzed in a model of microparametric variation, which takes into consideration the distribution of syntactic variables in geographical areas and formal analyses of syntactic properties (Barbiers, Cornips, and van der Kleij 2002). On the other hand, research on dialects of American English has focused mainly on morphosyntactic, phonological, and, to some extent, syntactic variables in the context of social factors, linguistic constraints, and variation and change. The focus on questions about origins has led to comparative analysis of dialects and English in early periods. By and large, the topic of variation and change in American English dialects has been the domain of sociolinguistics. Because one of the goals of sociolinguistics is to understand the correlation between social factors and linguistic variation and ordering of linguistic constraints with respect to variability of rules, variation theory is an integral part of the research paradigm. On the other hand, syntactic theory is not always incorporated in variation analyses, although it is clear that sociolinguists are concerned with theoretical notions of the scientific study of language. Along these same lines, there has not been a tradition of incorporating approaches to variation into syntactic theory (Wilson and Henry 1998). There have been at least three types of approaches to syntactic variation. The variable rule approach accounts for variability by allowing variable rules to apply in different contexts at different probability levels
Adipose-derived stem cells promote survival, growth, and maturation of early-stage murine follicles
Abstract
Background
Premature ovarian insufficiency is a common complication of anticancer treatments in young women and girls. The ovary is a complex, highly regulated reproductive organ, whose proper function is contingent upon the bidirectional endocrine, paracrine, and autocrine signaling. These factors facilitate the development of the follicles, the functional units of the ovary, to progress from the gonadotropin-independent, paracrine-controlled early stage to the gonadotropin-dependent, endocrine-controlled later stage. We hypothesized that the low survival rate of individually cultured early-stage follicles could be improved with co-culture of adipose-derived stem cells (ADSCs) that secrete survival- and growth-promoting factors.
Materials and methods
Ovarian follicles ranging from 85 to 115 μm in diameter, from 10- to 12-day-old B6CBAF1 mice were mechanically isolated and co-encapsulated with ADSCs within alginate-based 3D culture system. The follicles were cultured for 14 days, imaged using light microscopy every 2 days, and matured at the end. Follicle media were changed every 2 days and collected for hormone measurements. Follicle diameter, morphology, number of transzonal projections, and survival and maturation rates were recorded. Statistical analyses using one- and two-way ANOVA were performed to compare hormone levels, survival of the follicles and ADSCs, oocyte maturation rates, and follicle growth.
Results
The co-encapsulation of the follicles with ADSCs increased follicle survival, ranging from 42.4% for the 86–95 μm to 86.2% for the 106–115-μm follicle size group. Co-culture also improved the follicle growth, the rate of antrum formation and oocyte maturation compared to the follicles cultured alone. The levels of androstenedione, estradiol, and progesterone of co-encapsulated follicles increased progressively with time in culture.
Conclusions
To our knowledge, this is the first report of an in vitro system utilizing mouse adipose-derived stem cells to support the development of the mouse follicles. Our findings suggest that co-encapsulation of ADSCs with early-stage follicles supports follicular development, through secretion of cytokines that promote follicular survival, antrum formation, and meiotic competence. The unique 3D culture system that supports the survival of both cell types has translational implications, as ADSCs could be used as an autologous source for in vitro maturation of early-stage human follicles.https://deepblue.lib.umich.edu/bitstream/2027.42/148317/1/13287_2019_Article_1199.pd
PATHOS: A Brief Screening Application for Assessing Sexual Addiction
Sexual addiction is estimated to afflict up to 3% to 6% of the population. However, many clinicians lack clear criteria for detecting potential cases.
Objectives: The present studies were conducted to assess the effectiveness of a brief sexual addiction screening instrument (ie, PATHOS Questionnaire) to correctly classify patients being treated for sex addiction and healthy volunteers.
Methods: In study 1, a 6-item questionnaire, which utilizes the mnemonic PATHOS, was examined in regard to sensitivity and specificity using a sample combining patients being treated for sex addiction and healthy volunteers (970 men/80.2% patients; 938 women/63.8% patients). In study 2, a cross-validation sample of 672 men (93% patients) and 241 women (35.3% patients) completed the PATHOS screener.
Results: Results of receiver operating characteristics analyses in study 1 demonstrated that the PATHOS captured 92.6% of the area under the curve and achieved 88.3% sensitivity and 81.6% specificity for classifying the male sample (n = 963) as patients and healthy subjects using a cutoff score of 3. Similarly, the PATHOS captured 90.2% of the area under the curve and, with a cutoff of 3, achieved 80.9% sensitivity and 87.2% specificity for the female sample (n = 808). In study 2, results of receiver operating characteristics analyses indicated that the PATHOS captured 85.1% of the area under the curve, with sensitivity of 70.7% and specificity of 86.9% for men (cutoff of 3). For women, the PATHOS captured 80.9% of the area under the curve and achieved 69.7% sensitivity and 85.1% specificity with the cutoff of 3.
Conclusions: These studies provide support for the use of the PATHOS as a screening instrument to detect potential sexual addiction cases in clinical settings
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Investigating Morphosyntactic Variation in African American English on Twitter
Early work on African American English (AAE) perpetuated myths that the language variety was uniform across regions and that it was spoken primarily by working class men, due to being conducted in inner city areas and examining a specific set of linguistic features. These sociolinguistic myths negatively impacted not only the field of linguistics but also how the public viewed AAE. Since then studies have looked at a broader range of geographical areas and demonstrated distinct local differences. Here we build on this line of research by analyzing relative incidences of 18 morphosyntactic features in relationship to geographic and social factors, at scale. Our data is a corpus of 224M geotagged tweets, which is five orders of magnitude larger than previous social media studies of AAE. We use machine learning methods to automatically detect linguistic features and to identify common patterns of variation across the features. Our results show that, contrary to sociolinguistic myths of uniformity, there is clear variation in AAE across both geographic and social dimensions. Regionally, we see a distinct spatially contiguous southern core which aligns with national-level phonological and lexical variation in AAE, although it is less variable. Across social groups, there is higher AAE usage in the rural south and in Black-Hispanic contact communities – both of which are groups currently underrepresented in the literature. This work provides a significant advance in descriptive work on AAE morphosyntax, presenting the first national-level description and analysis of overall grammatical variation in AAE in order to answer key questions about variation in AAE. More broadly, our methods demonstrate how machine learning tools can be applied to large-scale real-world data to help us gain a more representative understanding of language in marginalized communities
Differential pathways to adult metabolic dysfunction following poor nutrition at two critical developmental periods in sheep
Epidemiological and experimental studies suggest early nutrition has long-term effects on susceptibility to obesity, cardiovascular and metabolic diseases. Small and large animal models confirm the influence of different windows of sensitivity, from fetal to early postnatal life, on offspring phenotype. We showed previously that undernutrition in sheep either during the first month of gestation or immediately after weaning induces differential, sex-specific changes in adult metabolic and cardiovascular systems. The current study aims to determine metabolic and molecular changes that underlie differences in lipid and glucose metabolism induced by undernutrition during specific developmental periods in male and female sheep. Ewes received 100% (C) or 50% nutritional requirements (U) from 1–31 days gestation, and 100% thereafter. From weaning (12 weeks) to 25 weeks, offspring were then fed either ad libitum (CC, UC) or were undernourished (CU, UU) to reduce body weight to 85% of their individual target. From 25 weeks, all offspring were fed ad libitum. A cohort of late gestation fetuses were studied after receiving either 40% nutritional requirements (1–31 days gestation) or 50% nutritional requirements (104–127 days gestation). Post-weaning undernutrition increased in vivo insulin sensitivity, insulin receptor and glucose transporter 4 expression in muscle, and lowered hepatic methylation at the delta-like homolog 1/maternally expressed gene 3 imprinted cluster in adult females, but not males. Early gestational undernutrition induced lower hepatic expression of gluconeogenic factors in fetuses and reduced in vivo adipose tissue insulin sensitivity in adulthood. In males, undernutrition in early gestation increased adipose tissue lipid handling mechanisms (lipoprotein lipase, glucocorticoid receptor expression) and hepatic methylation within the imprinted control region of insulin-like growth factor 2 receptor in adulthood. Therefore, undernutrition during development induces changes in mechanisms of lipid and glucose metabolism which differ between tissues and sexes dependent on the period of nutritional restriction. Such changes may increase later life obesity and dyslipidaemia risk
Intermediate filament–membrane attachments function synergistically with actin-dependent contacts to regulate intercellular adhesive strength
By tethering intermediate filaments (IFs) to sites of intercellular adhesion, desmosomes facilitate formation of a supercellular scaffold that imparts mechanical strength to a tissue. However, the role IF–membrane attachments play in strengthening adhesion has not been directly examined. To address this question, we generated Tet-On A431 cells inducibly expressing a desmoplakin (DP) mutant lacking the rod and IF-binding domains (DPNTP). DPNTP localized to the plasma membrane and led to dissociation of IFs from the junctional plaque, without altering total or cell surface distribution of adherens junction or desmosomal proteins. However, a specific decrease in the detergent-insoluble pool of desmoglein suggested a reduced association with the IF cytoskeleton. DPNTP-expressing cell aggregates in suspension or substrate-released cell sheets readily dissociated when subjected to mechanical stress whereas controls remained largely intact. Dissociation occurred without lactate dehydrogenase release, suggesting that loss of tissue integrity was due to reduced adhesion rather than increased cytolysis. JD-1 cells from a patient with a DP COOH-terminal truncation were also more weakly adherent compared with normal keratinocytes. When used in combination with DPNTP, latrunculin A, which disassembles actin filaments and disrupts adherens junctions, led to dissociation up to an order of magnitude greater than either treatment alone. These data provide direct in vitro evidence that IF–membrane attachments regulate adhesive strength and suggest furthermore that actin- and IF-based junctions act synergistically to strengthen adhesion
Re-positioning SoTL toward the T-shaped Community
Amongst a range of changes that have taken place within tertiary education, perhaps the most revolutionary has been a shift to student-centred approaches focused on life-long learning. Accompanying this approach to holistic higher education (HE) has been a growing interest in, and understanding of, the Scholarship of Teaching and Learning (SoTL). SoTL has, at its core, a deep concern with student learning and is therefore well-aligned with higher education’s renewed focus on its students. In this conceptual paper, we examine the impact of the T-shaped person which many tertiary institutions are operationalizing to inform and connect the development of students’ deep disciplinary knowledge with non-academic and employment readiness skills (such as communication, problem-solving, teamwork, and critical thinking). Importantly, we argue for a re-positioning of SoTL to complement and support this model, with SoTL as both the fulcrum and the fluid, multiple threads of discourse that are intricately entwined around the structure of the T-shaped model. We encourage our colleagues to strive to be T-shaped practitioners and we cast a vision of a T-shaped community. Here, all stakeholders within HE connect both their academic knowledge and holistic skills in collaborative ways to produce learners who flourish in modern society. The SoTL community plays a pivotal role in achieving this vision and is well-positioned to expand the current notion of SoTL toward a more holistic, interconnected, central role in HE
Whole-genome sequencing for national surveillance of Shiga toxin–producing Escherichia coli O157
Background. National surveillance of gastrointestinal pathogens, such as Shiga toxin–producing Escherichia coli O157 (STEC O157), is key to rapidly identifying linked cases in the distributed food network to facilitate public health interventions. In this study, we used whole-genome sequencing (WGS) as a tool to inform national surveillance of STEC O157 in terms of identifying linked cases and clusters and guiding epidemiological investigation. Methods. We retrospectively analyzed 334 isolates randomly sampled from 1002 strains of STEC O157 received by the Gastrointestinal Bacteria Reference Unit at Public Health England, Colindale, in 2012. The genetic distance between each isolate, as estimated by WGS, was calculated and phylogenetic methods were used to place strains in an evolutionary context. Results. Estimates of linked clusters representing STEC O157 outbreaks in England and Wales increased by 2-fold when WGS was used instead of traditional typing techniques. The previously unidentified clusters were often widely geographically distributed and small in size. Phylogenetic analysis facilitated identification of temporally distinct cases sharing common exposures and delineating those that shared epidemiological and temporal links. Comparison with multi locus variable number tandem repeat analysis (MLVA) showed that although MLVA is as sensitive as WGS, WGS provides a more timely resolution to outbreak clustering. Conclusions. WGS has come of age as a molecular typing tool to inform national surveillance of STEC O157; it can be used in real time to provide the highest strain-level resolution for outbreak investigation. WGS allows linked cases to be identified with unprecedented specificity and sensitivity that will facilitate targeted and appropriate public health investigations
Lexical Resource Integration across the Syntax-Semantics Interface
This paper examines extending a database of English verbs,
grouped into syntactico-semantic classes, with WordNet senses.
Probabilistic associations between theta-grids and WordNet verb
frames, SEMCOR frequency data, and disambiguation based on
an information-theoretic notion of semantic similarity are used.
Mapping successes and failures are illustrated with 'drop'.
(Cross-referenced as UMIACS-TR-2001-18)
(Cross-refereneced as LAMP-TR-068
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