38 research outputs found
A Step Forward: A Study of the Practical Application of the No Child Left Behind Act
This thesis analyzes teachers’ perceptions of the impact NCLB has on classrooms every day. It begins with a brief literature review analyzing and synthesizing editorial articles that discuss perceptions of the successes and shortcomings of NCLB. It then describes and discusses a survey study conducted amongst teachers in Southern Virginia. Thirty teachers from three counties were surveyed, and, as expected, when given space to respond freely, they responded with negative comments toward NCLB. However, when asked to rank the impact of the No Child Left Behind Act on student success and teacher effectiveness the surveyed teachers expressed a neutral impact. These mixed results indicate a need for further studies
Beluga Whale and Spotted Seal Use of a Coastal Lagoon System in the Northeastern Chukchi Sea
Aerial surveys were conducted in the northeastern Chukchi Sea during 1989-91 to investigate the distribution and abundance of beluga whales and spotted seals. Emphasis was on the 170 km long Kasegaluk Lagoon, which was known to be regularly used by both species during the open-water season. Belugas were seen on every survey during 3-14 July 1990 and 4-16 July 1991, with numbers ranging from 7 to 1212. Data from other years indicate that whales sometimes arrive as early as 22 June and leave the area by late July. The presence of nearshore gravel beds and warm, low-salinity water probably combine to make this region important as a place for belugas to molt. Spotted seals occur in the area from mid-July through early November. They haul out on particular spits and shoals near Utukok Pass, Akoliakatat Pass, and Avak Inlet. Numbers counted were variable but exceeded 1000 on many days in July, August, and September. Telemetry data suggest that the maximum count of about 2200 represents only a small portion of the total number of seals frequenting Kasegaluk Lagoon. Comparisons with data from previous years suggest that the numbers of belugas and spotted seals using the area have been relatively stable since the late 1970s. Activities associated with oil, gas, coal, and mineral resource development should be regulated to minimize their potential impacts on important beluga and spotted seal habitats.Key words: beluga whale, Delphinapterus leucas, spotted seal, Phoca largha, Chukchi Sea, Kasegaluk Lagoon, distribution, abundanceOn a effectué des relevés aériens dans la partie nord-est de la mer des Tchouktches au cours de la période allant de 1989 à 1991 dans le but d'enquêter sur la distribution et le nombre de bélougas et de veaux marins en se concentrant sur la lagune Kasegaluk longue de 170 km, qui avait la réputation d'accueillir régulièrement les deux espèces durant la saison d'eau libre. On a aperçu des bélougas lors de chacun des relevés effectués du 3 au 14 juillet 1990 et du 4 au 16 juillet 1991, en nombres allant de 7 à 1212. Les données provenant d'autres années révèlent que les baleines arrivent parfois dans la région dès le 22 juin et la quittent fin juillet. La présence de bancs de galets à proximité du rivage combinée à une eau tempérée et une faible salinité explique l'importance de cette zone comme site pour la mue des bélougas. Les veaux marins sont dans la région de la mi-juillet jusqu'au début novembre. Ils vont à terre sur des flèches littorales et des bancs de sable à proximité d'Utukok Pass, d'Akoliakatat Pass et de l'inlet Avak. Leur nombre variait mais était très souvent supérieur à 1000 en juillet, août et septembre. Les données de télémesure suggèrent que le nombre maximal d'environ 2200 ne représente qu'une petite partie du total des veaux marins fréquentant la lagune Kasegaluk. Des comparaisons avec des données provenant d'années antérieures suggèrent que le nombre des bélougas et des veaux marins qui utilisent la région est resté assez stable depuis la fin des années 1970. Les activités reliées à l'exploitation du pétrole, du gaz, du charbon et des ressources minérales devraient faire l'objet d'une réglementation afin que soient minimisées les retombées potentielles sur l'habitat du bélouga et celui du veau marin.Mots clés: bélouga, Delphinapterus leucas, veau marin, Phoca largha, mer des Tchouktches, lagune Kasegaluk, distribution, abondanc
Feeding of Bearded Seals in the Bering and Chukchi Seas and Trophic Interaction with Pacific Walruses
Current and historical information about food habits of bearded seals, Erignathus barbatus, are presented. Shrimps, crabs, and clams are overall the most important prey. Proportions of different prey in the diet vary with age of seals, location, and time of year. Foods of male and female seals are similar. Young seals eat proportionally more shrimps than do older animals. Recently, clams were important in the diet only in Norton Sound and near Wainwright, and only during late spring and summer. Greatest quantities of food were found in stomachs of seals which had eaten mostly clams. In Bering Strait, seals taken in spring 1958 and 1967 had consumed large quantities of clams, but this item was only a minor fraction of foods in 1975-79. Walruses, Odobenus rosmarus, have increased steadily in numbers since 1960. Whereas Bering Strait was mainly a route through which walruses migrated in spring and autumn, this region is now an area in which large numbers (up to 80,000) spend portions of the summer and autumn. The walruses feed mainly on clams. Increased foraging activity of walruses may have reduced availability of this food item for bearded seals. The walrus population currently appears to be exhibiting indications of stress. These indications may be a reflection of walrus numbers at or in excess of the ability of the clam resource to withstand current predation by walruses. Indices of population condition in bearded seals have remained stable, perhaps due to their more euryphagous habits
Factors Affecting the Observed Densities of Ringed Seals, Phoca hispida, in the Alaskan Beaufort Sea, 1996-99
Aerial surveys were conducted during late May and early June 1996-99 in the central Beaufort Sea of Alaska, using strip-transect methods. The purpose of these surveys was to quantify and model the effects of environmental covariates on ringed seal counts and to provide density estimates that would be useful for evaluating trends in seal abundance. Total survey effort included 40-88 transect lines per year covering 1198-2701 km². Observed densities ranged from 0.81 seals/km² in 1996 to 1.17 seals/km² in 1999. We examined the effects of habitat, weather, and time of day on observed seal densities, using univariate chi-square goodness-of-fit tests. We also used a multivariate generalized linear model to estimate the relationship between seal counts and covariates. Three habitat-related variables - water depth, location relative to the fast ice edge, and ice deformation - had substantial and consistent effects. The highest densities occurred at depths between 5 and 35 m. Densities were also highest in relatively flat ice and near the fast ice edge, declining both shoreward and seaward of that edge. Univariate analysis suggested that observed densities were generally highest at about 1200 h Alaska daylight time, but time was not a significant variable in the generalized linear models. Analyses of the effects of weather factors on seal counts were inconclusive. This was likely at least partially because temperature and wind speed were measured at survey altitude, rather than on the ice surface, and surveys were conducted only in weather considered suitable for hauling out. The final multivariate model did not account for a substantial proportion of the variation in seal counts. We think this result was largely due to date-related variation in the proportion of seals hauling out, an issue our surveys were not suited to address.De 1996 à 1999, à la fin de mai et au début de juin, on a effectué des relevés aériens dans la partie centrale de la mer de Beaufort alaskienne, en utilisant des méthodes d'échantillonnage en bande. Ces relevés avaient pour but de quantifier et de modéliser les effets de covariables environnementales sur le comptage des phoques annelés, et de fournir des estimations de densité qui pourraient servir à évaluer les tendances dans l'abondance des phoques. Le travail de relevé a porté chaque année sur un total allant de 40 à 88 lignes-transects, couvrant une superficie de 1198 à 2701 km². Les densités observées allaient de 0,81 phoque par km² en 1996 à 1,17 phoque par km² en 1999. On a étudié les effets de l'habitat, du climat et du moment de la journée sur les densités de phoques observées, à l'aide de tests d'adéquation chi carré à une variable. On a également eu recours à un modèle linéaire généralisé à plusieurs variables pour évaluer le rapport entre les comptages de phoques et les covariables. Trois variables reliées à l'habitat - profondeur de l'eau, position par rapport à la lisière de la banquise côtière et déformation de la glace - avaient des effets importants et constants. Les plus fortes densités se produisaient à des profondeurs de 5 à 35 m. Elles se retrouvaient également sur la glace relativement plane et près de la lisière de la banquise côtière, diminuant à la fois en direction du rivage et en direction de la mer depuis la lisière. L'analyse à une variable suggère que les densités observées étaient généralement plus fortes à environ 12 h (heure avancée de l'Alaska), mais le moment de la journée ne constituait pas une variable d'importance dans les modèles linéaires généralisés. Les analyses de l'impact des facteurs météorologiques sur les comptages de phoques n'ont pas donné de résultats concluants. Ceci était probablement dû au moins en partie au fait que la température et la vitesse du vent étaient mesurées à l'altitude où se faisaient les relevés plutôt qu'à la surface de la glace, et les relevés n'étaient effectués que par temps jugé approprié pour que les phoques montent sur la glace. Le modèle final à plusieurs variables ne représentait pas une proportion substantielle de la variation dans les comptages de phoques. Ce résultat, selon nous, était dû en grande partie à une fluctuation reliée à la date dans la proportion de phoques qui montaient sur la glace, question que nos relevés n'étaient pas conçus pour aborder
Breast cancer risk, worry, and anxiety: Effect on patient perceptions of false-positive screening results
OBJECTIVE: The impact of mammography screening recall on quality-of-life (QOL) has been studied in women at average risk for breast cancer, but it is unknown whether these effects differ by breast cancer risk level. We used a vignette-based survey to evaluate how women across the spectrum of breast cancer risk perceive the experience of screening recall.
METHODS: Women participating in mammography or breast MRI screening were recruited to complete a vignette-based survey. Using a numerical rating scale (0-100), women rated QOL for hypothetical scenarios of screening recall, both before and after benign results were known. Lifetime breast cancer risk was calculated using Gail and BRCAPRO risk models. Risk perception, trait anxiety, and breast cancer worry were assessed using validated instruments.
RESULTS: The final study cohort included 162 women at low (n = 43, 26%), intermediate (n = 66, 41%), and high-risk (n = 53, 33%). Actual breast cancer risk was not a predictor of QOL for any of the presented scenarios. Across all risk levels, QOL ratings were significantly lower for the period during diagnostic uncertainty compared to after benign results were known (p \u3c 0.05). In multivariable regression analyses, breast cancer worry was a significant predictor of decreased QoL for all screening scenarios while awaiting results, including scenarios with non-invasive imaging alone or with biopsy. High trait anxiety and family history predicted lower QOL scores after receipt of benign test results (p \u3c 0.05).
CONCLUSIONS: Women with high trait anxiety and family history may particularly benefit from discussions about the risk of recall when choosing a screening regimen
DNA methylation signatures of aggression and closely related constructs : A meta-analysis of epigenome-wide studies across the lifespan
DNA methylation profiles of aggressive behavior may capture lifetime cumulative effects of genetic, stochastic, and environmental influences associated with aggression. Here, we report the first large meta-analysis of epigenome-wide association studies (EWAS) of aggressive behavior (N = 15,324 participants). In peripheral blood samples of 14,434 participants from 18 cohorts with mean ages ranging from 7 to 68 years, 13 methylation sites were significantly associated with aggression (alpha = 1.2 x 10(-7); Bonferroni correction). In cord blood samples of 2425 children from five cohorts with aggression assessed at mean ages ranging from 4 to 7 years, 83% of these sites showed the same direction of association with childhood aggression (r = 0.74, p = 0.006) but no epigenome-wide significant sites were found. Top-sites (48 at a false discovery rate of 5% in the peripheral blood meta-analysis or in a combined meta-analysis of peripheral blood and cord blood) have been associated with chemical exposures, smoking, cognition, metabolic traits, and genetic variation (mQTLs). Three genes whose expression levels were associated with top-sites were previously linked to schizophrenia and general risk tolerance. At six CpGs, DNA methylation variation in blood mirrors variation in the brain. On average 44% (range = 3-82%) of the aggression-methylation association was explained by current and former smoking and BMI. These findings point at loci that are sensitive to chemical exposures with potential implications for neuronal functions. We hope these results to be a starting point for studies leading to applications as peripheral biomarkers and to reveal causal relationships with aggression and related traits.Peer reviewe
Minimal information for studies of extracellular vesicles 2018 (MISEV2018):a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines
The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
DNA methylation signatures of aggression and closely related constructs: A meta-analysis of epigenome-wide studies across the lifespan
DNA methylation profiles of aggressive behavior may capture lifetime cumulative effects of genetic, stochastic, and environmental influences associated with aggression. Here, we report the first large meta-analysis of epigenome-wide association studies (EWAS) of aggressive behavior (N = 15,324 participants). In peripheral blood samples of 14,434 participants from 18 cohorts with mean ages ranging from 7 to 68 years, 13 methylation sites were significantly associated with aggression (alpha = 1.2 × 10-7; Bonferroni correction). In cord blood samples of 2425 children from five cohorts with aggression assessed at mean ages ranging from 4 to 7 years, 83% of these sites showed the same direction of association with childhood aggression (r = 0.74, p = 0.006) but no epigenome-wide significant sites were found. Top-sites (48 at a false discovery rate of 5% in the peripheral blood meta-analysis or in a combined meta-analysis of peripheral blood and cord blood) have been associated with chemical exposures, smoking, cognition, metabolic traits, and genetic variation (mQTLs). Three genes whose expression levels were associated with top-sites were previously linked to schizophrenia and general risk tolerance. At six CpGs, DNA methylation variation in blood mirrors variation in the brain. On average 44% (range = 3-82%) of the aggression-methylation association was explained by current and former smoking and BMI. These findings point at loci that are sensitive to chemical exposures with potential implications for neuronal functions. We hope these results to be a starting point for studies leading to applications as peripheral biomarkers and to reveal causal relationships with aggression and related traits.</p
Comparative genome structure, secondary metabolite, and effector coding capacity across Cochliobolus pathogens.
The genomes of five Cochliobolus heterostrophus strains, two Cochliobolus sativus strains, three additional Cochliobolus species (Cochliobolus victoriae, Cochliobolus carbonum, Cochliobolus miyabeanus), and closely related Setosphaeria turcica were sequenced at the Joint Genome Institute (JGI). The datasets were used to identify SNPs between strains and species, unique genomic regions, core secondary metabolism genes, and small secreted protein (SSP) candidate effector encoding genes with a view towards pinpointing structural elements and gene content associated with specificity of these closely related fungi to different cereal hosts. Whole-genome alignment shows that three to five percent of each genome differs between strains of the same species, while a quarter of each genome differs between species. On average, SNP counts among field isolates of the same C. heterostrophus species are more than 25× higher than those between inbred lines and 50× lower than SNPs between Cochliobolus species. The suites of nonribosomal peptide synthetase (NRPS), polyketide synthase (PKS), and SSP-encoding genes are astoundingly diverse among species but remarkably conserved among isolates of the same species, whether inbred or field strains, except for defining examples that map to unique genomic regions. Functional analysis of several strain-unique PKSs and NRPSs reveal a strong correlation with a role in virulence