2,702 research outputs found
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Re-Designing Infrastructure as a Strategy for Crafting Coherence Across Three Networks Focused on the Implementation of the Next Generation Science Standards
This design-based research project reports on three multilevel networks that were focused on implementing the Next Generation Science Standards (NGSS). Given the recent attention to understanding infrastructure to craft coherence in NGSS implementation, this research investigated how these networks iteratively re-designed infrastructure as they engaged in implementing the NGSS. This focus is particularly important in the current context of NGSS implementation since needed infrastructure did not accompany the dissemination of the standards. The three networks were the following: mentor teachers, district specialists, and interim assessment specialists. Qualitative cases based on recordings of network working sessions, interviews with members, and artifacts of their work were generated for each network and then compared and contrasted. Findings show the work on infrastructure re-design across the networks not only involved identifying useful NGSS-designed resources and frameworks, but also translating these into meaningful supports or scaffolds that could ultimately lead to productive forms of engagement for either supporting teacher professional learning or student learning. Also, collegial workspaces were beneficial for institutionalizing networks\u27 foci by creating spaces for all actors to share their experiences, challenges, and needs. This meant focusing on curriculum and instructional routines for mentor teachers, focusing on NGSS instructional principles for district leaders, and focusing on the development of an interim assessment practice brief for interim assessment leaders—foci identified as central to and immediately applicable in the day-to-day work of the respective network members
SAF-A mutants disrupt chromatin structure through dominant negative effects on RNAs associated with chromatin
Here we provide a brief review of relevant background before presenting results of our investigation into the interplay between scaffold attachment factor A (SAF-A), chromatin-associated RNAs, and DNA condensation. SAF-A, also termed heterogenous nuclear protein U (hnRNP U), is a ubiquitous nuclear scaffold protein that was implicated in XIST RNA localization to the inactive X-chromosome (Xi) but also reported to maintain open DNA packaging in euchromatin. Here we use several means to perturb SAF-A and examine potential impacts on the broad association of RNAs on euchromatin, and on chromatin compaction. SAF-A has an N-terminal DNA binding domain and C-terminal RNA binding domain, and a prominent model has been that the protein provides a single-molecule bridge between XIST RNA and chromatin. Here analysis of the impact of SAF-A on broad RNA-chromatin interactions indicate greater biological complexity. We focus on SAF-A\u27s role with repeat-rich C0T-1 hnRNA (repeat-rich heterogeneous nuclear RNA), shown recently to comprise mostly intronic sequences of pre-mRNAs and diverse long non-coding RNAs (lncRNAs). Our results show that SAF-A mutants cause dramatic changes to cytological chromatin condensation through dominant negative effects on C0T-1 RNA\u27s association with euchromatin, and likely other nuclear scaffold factors. In contrast, depletion of SAF-A by RNA interference (RNAi) had no discernible impact on C0T-1 RNA, nor did it cause similarly marked chromatin changes as did three different SAF-A mutations. Overall results support the concept that repeat-rich, chromatin-associated RNAs interact with multiple RNA binding proteins (RBPs) in a complex dynamic meshwork that is integral to larger-scale chromatin architecture and collectively influences cytological-scale DNA condensation
New Barriers to Participation: Application of New Mexico's Voter Identification Law
In democratic societies there is a tension between maximizing ballot access and minimizing voter fraud. Since the 2000 presidential election, this tension has been central to discussions about election reform, at the national and local level. We examine this tension by focusing on the implementation of voter identification laws in one state that has experienced significant issues in recent elections, and that is now implementing significant attempts at election reform: New Mexico. We hypothesized that Hispanic voters were more likely to show some form of identification than other types of voters. Using a voter data set from New Mexico’s First Congressional District in the 2006 election, we find that Hispanic, male and Election Day voters were more likely to show some form of identification than non-Hispanic, female and early voters. In addition, using an overlapping study of Bernalillo County 2006 poll workers, we find no evidence that certain groups of poll workers were more likely to ask for voter identification. Our findings suggest that broad voter identification laws, which may be applied unequally, may be perceived as discriminatory
PCV23: VARIATION IN COSTS OF TREATING HYPERCHOLESTEROLEMIC PATIENTS IN FRANCE
The evolution of male ornamentation has long been the focus of sexual selection studies. However, evidence is accumulating that sexually selected traits can also be lost, although the process is ill-understood. In male fairy-wrens (Malurus spp.), early molt into the seasonal breeding plumage is critical for obtaining extra-pair paternity (EPP), which reaches very high levels in these socially monogamous songbirds. A notable exception is the purple-crowned fairy-wren, Malurus coronatus, which, like its congeners, breeds cooperatively, but where EPP is very rare. Nevertheless, males develop a conspicuous seasonal breeding plumage at highly variable times. Based on 6 years of molt data collected for 137 individuals, we investigated the adaptive significance of pre-breeding molt timing as a sexual signal under (near) genetic monogamy. Molt timing varied between and within individuals with age and climate: molt was completed earlier in older males and after wetter years. Despite its potential to act as a sexual signal of male quality, fitness benefits and costs of early molt appear limited: molt timing did not correlate with 1) the likelihood of gaining a breeding position; 2) female mate preference (EPP/cuckoldry, divorce); 3) female reproductive investment (breeding timing, clutch size, number of clutches); 4) breeding performance (hatching success, fledging success, fledgling survival, annual reproductive success); and 5) male survival. However, although molt timing did not predict which subordinates would become breeders, breeders molted earlier than subordinates. The lack of EPP in this species might imply relaxed sexual selection on early molt with potential to lead to trait disappearance
Cosmological Constraints on Dissipative Models of Inflation
(Abridged) We study dissipative inflation in the regime where the dissipative
term takes a specific form, \Gamma=\Gamma(\phi), analyzing two models in the
weak and strong dissipative regimes with a SUSY breaking potential. After
developing intuition about the predictions from these models through analytic
approximations, we compute the predicted cosmological observables through full
numerical evolution of the equations of motion, relating the mass scale and
scale of dissipation to the characteristic amplitude and shape of the
primordial power spectrum. We then use Markov Chain Monte Carlo techniques to
constrain a subset of the models with cosmological data from the cosmic
microwave background (WMAP three-year data) and large scale structure (SDSS
Luminous Red Galaxy power spectrum). We find that the posterior distributions
of the dissipative parameters are highly non-Gaussian and their allowed ranges
agree well with the expectations obtained using analytic approximations. In the
weak regime, only the mass scale is tightly constrained; conversely, in the
strong regime, only the dissipative coefficient is tightly constrained. A lower
limit is seen on the inflation scale: a sub-Planckian inflaton is disfavoured
by the data. In both weak and strong regimes, we reconstruct the limits on the
primordial power spectrum and show that these models prefer a {\it red}
spectrum, with no significant running of the index. We calculate the reheat
temperature and show that the gravitino problem can be overcome with large
dissipation, which in turn leads to large levels of non-Gaussianity: if
dissipative inflation is to evade the gravitino problem, the predicted level of
non-Gaussianity might be seen by the Planck satellite.Comment: 14 pages, 9 figures, Accepted by JCAP without text changes,
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Developing district-level infrastructure that honors local control while emphasizing collaboration
Strategic Planning for Local Tourism Destinations: An Analysis of Tourism
This paper reports on a study of the planning practices of local tourism destinations. The tourism plans of 30 local tourism destinations in Queensland, Australia were analyzed to determine the extent to which sustainability principles, namely strategic planning and stakeholder participation, were integrated into the planning process. Utilizing a tourism planning process evaluation instrument developed by Simpson (2001), it was found that local tourism destinations are not integrating sustainability principles in their planning processes
Loss of miRNA biogenesis induces p19Arf-p53 signaling and senescence in primary cells
Dicer, an enzyme involved in microRNA (miRNA) maturation, is required for proper cell differentiation and embryogenesis in mammals. Recent evidence indicates that Dicer and miRNA may also regulate tumorigenesis. To better characterize the role of miRNA in primary cell growth, we generated Dicer-conditional mice. Ablation of Dicer and loss of mature miRNAs in embryonic fibroblasts up-regulated p19Arf and p53 levels, inhibited cell proliferation, and induced a premature senescence phenotype that was also observed in vivo after Dicer ablation in the developing limb and in adult skin. Furthermore, deletion of the Ink4a/Arf or p53 locus could rescue fibroblasts from premature senescence induced by Dicer ablation. Although levels of Ras and Myc oncoproteins appeared unaltered, loss of Dicer resulted in increased DNA damage and p53 activity in these cells. These results reveal that loss of miRNA biogenesis activates a DNA damage checkpoint, up-regulates p19Arf-p53 signaling, and induces senescence in primary cells
The impact of storage conditions on human stool 16S rRNA microbiome composition and diversity
Background: Multiple factors can influence stool sample integrity upon sample
collection. Preservation of faecal samples for microbiome studies is therefore an
important step, particularly in tropical regions where resources are limited and
high temperatures may significantly influence microbiota profiles. Freezing is the
accepted standard to preserve faecal samples however, cold chain methods are often
unfeasible in fieldwork scenarios particularly in low and middle-income countries
and alternatives are required. This study therefore aimed to address the impact of
different preservative methods, time-to-freezing at ambient tropical temperatures,
and stool heterogeneity on stool microbiome diversity and composition under
real-life physical environments found in resource-limited fieldwork conditions.
Methods: Inner and outer stool samples collected from one specimen obtained from
three children were stored using different storage preservation methods (raw, ethanol
and RNAlater) in a Ugandan field setting. Mixed stool was also stored using these
techniques and frozen at different time-to-freezing intervals post-collection from
0–32 h. Metataxonomic profiling was used to profile samples, targeting the V1–V2
regions of 16S rRNA with samples run on a MiSeq platform. Reads were trimmed,
combined and aligned to the Greengenes database. Microbial diversity and
composition data were generated and analysed using Quantitative Insights Into
Microbial Ecology and R software.
Results: Child donor was the greatest predictor of microbiome variation between the
stool samples, with all samples remaining identifiable to their child of origin
despite the stool being stored under a variety of conditions. However, significant
differences were observed in composition and diversity between preservation
techniques, but intra-preservation technique variation was minimal for all
preservation methods, and across the time-to-freezing range (0–32 h) used. Stool
heterogeneity yielded no apparent microbiome differences.
Conclusions: Stool collected in a fieldwork setting for comparative microbiome
analyses should ideally be stored as consistently as possible using the same
preservation method throughout
Centriolar satellites expedite mother centriole remodeling to promote ciliogenesis
Centrosomes are orbited by centriolar satellites, dynamic multiprotein assemblies nucleated by Pericentriolar material 1 (PCM1). To study the requirement for centriolar satellites, we generated mice lacking PCM1, a crucial component of satellites. Pcm1−/− mice display partially penetrant perinatal lethality with survivors exhibiting hydrocephalus, oligospermia, and cerebellar hypoplasia, and variably expressive phenotypes such as hydronephrosis. As many of these phenotypes have been observed in human ciliopathies and satellites are implicated in cilia biology, we investigated whether cilia were affected. PCM1 was dispensable for ciliogenesis in many cell types, whereas Pcm1−/− multiciliated ependymal cells and human PCM1−/− retinal pigmented epithelial 1 (RPE1) cells showed reduced ciliogenesis. PCM1−/− RPE1 cells displayed reduced docking of the mother centriole to the ciliary vesicle and removal of CP110 and CEP97 from the distal mother centriole, indicating compromised early ciliogenesis. Similarly, Pcm1−/− ependymal cells exhibited reduced removal of CP110 from basal bodies in vivo. We propose that PCM1 and centriolar satellites facilitate efficient trafficking of proteins to and from centrioles, including the departure of CP110 and CEP97 to initiate ciliogenesis, and that the threshold to trigger ciliogenesis differs between cell types
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