340 research outputs found
A study of maternal attitudes and how they effect treatment with children in the cases known to West End Child Guidance Clinic, Boston, Massachusetts from June 1947 through July 1948
Thesis (M.S.)--Boston University, 1949. This item was digitized by the Internet Archive
Role of atmospheric indices in describing shoreline variability along the Atlantic coast of Europe
The data set consists of time series atmospheric indicates, wave conditions and beach morphology for three sites on the Atlantic coast of EuropeThe project investigate the connections between atmospheric indicates, wave conditions and beach change over a 15-20 year period for three beach on the Atlantic coast of Europ
Time series aggregation, disaggregation and long memory
We study the aggregation/disaggregation problem of random parameter AR(1)
processes and its relation to the long memory phenomenon. We give a
characterization of a subclass of aggregated processes which can be obtained
from simpler, "elementary", cases. In particular cases of the mixture
densities, the structure (moving average representation) of the aggregated
process is investigated
Role of Atmospheric Indices in Describing Shoreline Variability Along the Atlantic Coast of Europe
Beaches are highly variable environments and respond to changes in wave forcing, themselves modulated by climate variability. Here, we analyze three highâquality beach profile data sets to robustly investigate, for the first time, the link between shoreline change, wave forcing and climate variability along the Atlantic coast of Europe. Winter wave conditions are strongly associated with North Atlantic Oscillation (NAO) and Western Europe Pressure Anomaly (WEPA), with WEPA explaining 50%â80% of the winter wave power variability. Shoreline variability during winter is also strongly linked to NAO and WEPA, with WEPA explaining 25% of the winter shoreline variability. Winter wave conditions and associated shoreline variability are both unrelated to El Nino Southern Oscillation. In addition to the atmosphericallyâforced beach morphological response, shoreline change also depends strongly on the antecedent morphology as evidenced by significant correlations between summer/winter shoreline response and the shoreline position at the start of each season
On the influence of reflection over a rhythmic swash zone on surf zone dynamics
The reflection of incident gravity waves over an irregular swash zone morphology and the resulting influence on surf zone dynamics remains mostly unexplored. The wave-phase resolving SWASH model is applied to investigate this feedback using realistic low-tide terraced beach morphology with well-developed beach cusps. The rhythmic reflection generates a standing wave that mimics a subharmonic edge wave, from the superimposition of incident and two-dimensional reflected waves. This mechanism is enhanced by shore-normal, narrow-banded waves in both direction and frequency. Our study suggests that wave reflection over steep beaches could be a mechanism for the development of rhythmic morphological features such as beach cusps and rip currents
Understanding coastal morphodynamic patterns from depth-averaged sediment concentration
This review highlights the important role of the depth-averaged sediment concentration (DASC) to understand the formation of a number of coastal morphodynamic features that have an alongshore rhythmic pattern: beach cusps, surf zone transverse and crescentic bars, and shoreface-connected sand ridges. We present a formulation and methodology, based on the knowledge of the DASC (which equals the sediment load divided by the water depth), that has been successfully used to understand the characteristics of these features. These sand bodies, relevant for coastal engineering and other disciplines, are located in different parts of the coastal zone and are characterized by different spatial and temporal scales, but the same technique can be used to understand them. Since the sand bodies occur in the presence of depth-averaged currents, the sediment transport approximately equals a sediment load times the current. Moreover, it is assumed that waves essentially mobilize the sediment, and the current increases this mobilization and advects the sediment. In such conditions, knowing the spatial distribution of the DASC and the depth-averaged currents induced by the forcing (waves, wind, and pressure gradients) over the patterns allows inferring the convergence/divergence of sediment transport. Deposition (erosion) occurs where the current flows from areas of high to low (low to high) values of DASC. The formulation and methodology are especially useful to understand the positive feedback mechanisms between flow and morphology leading to the formation of those morphological features, but the physical mechanisms for their migration, their finite-amplitude behavior and their decay can also be explored
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Genomic resolution of a cold subsurface aquifer community provides metabolic insights for novel microbes adapted to high CO2 concentrations.
As in many deep underground environments, the microbial communities in subsurface high-CO2 ecosystems remain relatively unexplored. Recent investigations based on single-gene assays revealed a remarkable variety of organisms from little studied phyla in Crystal Geyser (Utah, USA), a site where deeply sourced CO2 -saturated fluids are erupted at the surface. To provide genomic resolution of the metabolisms of these organisms, we used a novel metagenomic approach to recover 227 high-quality genomes from 150 microbial species affiliated with 46 different phylum-level lineages. Bacteria from two novel phylum-level lineages have the capacity for CO2 fixation. Analyses of carbon fixation pathways in all studied organisms revealed that the Wood-Ljungdahl pathway and the Calvin-Benson-Bassham Cycle occurred with the highest frequency, whereas the reverse TCA cycle was little used. We infer that this, and selection for form II RuBisCOs, are adaptions to high CO2 -concentrations. However, many autotrophs can also grow mixotrophically, a strategy that confers metabolic versatility. The assignment of 156 hydrogenases to 90 different organisms suggests that H2 is an important inter-species energy currency even under gaseous CO2 -saturation. Overall, metabolic analyses at the organism level provided insight into the biochemical cycles that support subsurface life under the extreme condition of CO2 saturation
Collaborative and consultative patient and public involvement in sexual health research:lessons learnt from four case studies
Objectives: Patient and Public Involvement (PPI) is increasingly mandated in health research. However, there is little guidance on conducting PPI for research on episodic infections, risk factors, hard-to-reach populations, or stigmatised behaviours. The aim of this paper is to address the gap in PPI guidance by illustrating different approaches to challenging PPI scenarios. Methods: Four case studies of sexual health research PPI, each of which discusses three stages of PPI (defining, accessing and engaging with lay advisors). Results: Researchers may need to use broadly define lay advisors; involving those with insight into population of interest can be beneficial. Alternative and multiple routes to access patients/public should be considered. Flexible means of engagement can enable lay advisors to contribute anonymously, remotely and/or opportunistically. Conclusions: Case studies may help researchers in sexual health (and other fields) to better meet the challenges of PPI for studies which concern hard-to-reach populations, episodic infections, risk factors, and stigmatised behaviours
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Clades of huge phages from across Earth's ecosystems.
Bacteriophages typically have small genomes1 and depend on their bacterial hosts for replication2. Here we sequenced DNA from diverse ecosystems and found hundreds of phage genomes with lengths of more than 200 kilobases (kb), including a genome of 735 kb, which is-to our knowledge-the largest phage genome to be described to date. Thirty-five genomes were manually curated to completion (circular and no gaps). Expanded genetic repertoires include diverse and previously undescribed CRISPR-Cas systems, transfer RNAs (tRNAs), tRNA synthetases, tRNA-modification enzymes, translation-initiation and elongation factors, and ribosomal proteins. The CRISPR-Cas systems of phages have the capacity to silence host transcription factors and translational genes, potentially as part of a larger interaction network that intercepts translation to redirect biosynthesis to phage-encoded functions. In addition, some phages may repurpose bacterial CRISPR-Cas systems to eliminate competing phages. We phylogenetically define the major clades of huge phages from human and other animal microbiomes, as well as from oceans, lakes, sediments, soils and the built environment. We conclude that the large gene inventories of huge phages reflect a conserved biological strategy, and that the phages are distributed across a broad bacterial host range and across Earth's ecosystems
Role of Atmospheric Indices in Describing Inshore Directional Wave Climate in the United Kingdom and Ireland
Improved understanding of how our coasts will evolve over a range of time scales (yearsâdecades) is critical for effective and sustainable management of coastal infrastructure. A robust knowledge of the spatial, directional and temporal variability of the inshore wave climate is required to predict future coastal evolution and hence vulnerability. However, the variability of the inshore directional wave climate has received little attention, and an improved understanding could drive development of skillful seasonal or decadal forecasts of coastal response. We examine inshore wave climate at 63 locations throughout the United Kingdom and Ireland (1980â2017) and show that 73% are directionally bimodal. We find that winterâaveraged expressions of six leading atmospheric indices are strongly correlated (r = 0.60â0.87) with both total and directional winter wave power (peak spectral wave direction) at all studied sites. Regional inshore wave climate classification through hierarchical cluster analysis and stepwise multiâlinear regression of directional wave correlations with atmospheric indices defined four spatially coherent regions. We show that combinations of indices have significant skill in predicting directional wave climates (R2 = 0.45â0.8; p<0.05). We demonstrate for the first time the significant explanatory power of leading winterâaveraged atmospheric indices for directional wave climates, and show that leading seasonal forecasts of the NAO skillfully predict wave climate in some regions.
Plain Language Summary
Understanding the seasonal variability in wave climate around our coasts is fundamental for improving our understanding of how coasts will respond to climate change and seaâlevel rise. Recent research has highlighted the importance of wave direction on coastal response. In this study we specifically explore the seasonal variability in wave direction throughout the inshore regions of the United Kingdom and Ireland at 63 locations between 1980 and 2017. We find that 73% of sites examined are directionally bimodal. We also find that combinations of six of the regions leading climate indices (NAO, AO, WEPA, EA, SCAND, EA/WR) are strongly correlated with both total and directional winter wave power at all the studied sites. We show that regression models using combinations of these climate indices have significant skill in predicting directional wave climates over the period 1980â2017. For the first time we show that 'seasonal ahead' forecasts of the NAO can skilfully predict wave climate in some regions of the United Kingdom and Ireland, which could be used as tool to support coastal hazard mitigation
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