Small-scale star formation at low metallicity

Massive star formation in a low metallicity environment is investigated by studying the morphology of small HII regions in the Small Magellanic Cloud. A classification scheme based upon the symmetry of form in the light of H-alpha is proposed to make possible an examination of the properties of blister candidates with respect to nebulas embedded in a more uniform medium. A new diagnostic of size is developed to derive quantitative information about the ionized gas and ionizing stars. The asymmetrical surface-brightness distribution of many HII regions demonstrates that massive stars often form at the edge of dense neutral clouds. However, the existence of many symmetrical nebulas with similar sizes, luminosities, and surface brightnesses shows that massive star formation often occurs within these clouds. Nevertheless, the statistics of the two different forms indicate that the rate of massive star formation declines less steeply with radius across host clouds than in the Milky Way, suggesting that external triggering may play a larger role in initiating star formation

Relationship of Main Pulmonary Artery Diameter to Pulmonary Arterial Pressure in Scleroderma Patients with and without Mild to Moderate Interstitial Fibrosis

Purpose: To determine the validity of main pulmonary artery diameter (MPAD) as a marker of pulmonary hypertension in scleroderma patients with and without interstitial lung disease (lLD). Materials and Methods: We cross-referenced the radiologic database with medical records to identify patients with both computed tomography (CT) scans of the chest and right-heart catheterization separated by no more than six months. Computed tomography scans were reviewed to determine MPAD and extent of ILD for each patient. Ground glass opacity and fibrosis were individually scored by a single thoracic radiologist on a five-point scale. The same radiologist also determined the quality of delineation for the great vessels. MPAD was calculated based on the average of measurements taken from two separate observers. Mean pulmonary arterial pressures (mPAP) were determined by RHC. Patients were divided into either group A (n = 20) or group B (n = 27) based on the absence or presence of interstitial fibrosis respectively. Patients with available data from pulmonary function tests (PFTs) were divided into those with FVC \u3e 70% predicted (Group C) and those with FVC \u3c 70% predicted (Group D). Groups were compared using either the Student t test or Mann-Whitney U test depending on the distribution of each variable under consideration. Either the Pearson correlation coefficient or the Spearman rank-correlation coefficient was calculated for each group to evaluate the relationship between MPAD and mPAP. Results: Groups A and B were similar with regard to MPAD (p = 0.28) and mPAP (p = 0.34) upon Mann-Whitney U testing. MPAD was strongly correlated with mPAP in both Group A (r = 0.68, P = 0.001) and Group B (r = 0.70, P \u3c 0.0001). The correlation between MPAD and mPAP in Group C (r = 0.69, P = 0.002) was substantially higher than that in Group 0 (r = 0.42, P = 0.11). Conclusion: In our patient sample with scleroderma, MPAD is strongly correlated with mPAP and may indicate the development of pulmonary hypertension regardless of the presence of mild to moderate interstitial fibrosis. An increase in the severity of restrictive lung disease as measured by FVC appears to attenuate the correlation between MPAO and mPAP

Some Components of Sediment Oxygen Demand in Lake Erie Sediments

Research on which this report is based was financed in part by the U. S, Department of Interior as authorized by the Water Resources and Development Act of 1978, (P. L. 95-467).(print) 40 leaves : ill. ; 28 cm.Item lacks publicaton date. Date supplied from WorldCat bibliographic recordWe have examined SOD of Lake Erie sediments with and without macrobenthic infauna, and with high and low macrobial activity, and have modeled the penetration of oxygen into sediments, since the depth of oxygen penetration is not easily measured. SOD of western and central basin sediments (95% silt clay, 3% organic carbon, 70-80% water content) ranges from 1.25-2.5 um 02/hr in laboratory microcosms. When tubificid oligochaetes are added to laboratory microcosms (30,000 m^-2 ), SOD rises to 1.5-3.5 um 02/hr. SOD is greater than the simple sum of organism respiration plus sediment SOD. The extra enhanced demand is due to enhanced microbial activity, the transport of 02 to greater depths in the sediment, and to the transport by feeding of FeS to the sediment-water interface. Enhanced demand over sediment plus respiration values appear to be proportional to the number of oligochaetes present, which would implicate FeS transport as a major factor in enhanced demand. Thus, tubificids enhance the rate of organic decay not only through aiding the transport of dissolved oxygen, but also by transporting reduced sulphur to be oxidized to SO4^2- at the sediment-water interface. Sediment sterilization techniques were not successful; these techniques probably result in the release of additional oxygen demanding substances as a result of sterilization. There is a pattern of decreasing SOD for a period of about 10-14 days after the start of an experiment until an equilibrium SOD is reached. This is due to the liberation of bacterial nutrients when sediments are added to microcosms and mixed. Thus experiments done soon after introduction of sediments into an SOD apparatus are likely to be in error by as much as a factor of two.Disclaimer -- Contents -- Abstract -- Figures -- Tables -- Background -- Conclusions and Recommendations -- Introduction -- Review of Related Research -- Geochemical Considerations -- Methods -- Results -- Bibliograph

Integrating Developmental Scholarship and Society: From Dissemination and Accountability to Evidence-Based Programming and Policies

Increasingly, practitioners and policy makers are demanding research evidence as a basis for funding programs and policies. The application of research to society has undergone several transitions, from a scholarly emphasis on the experimental method to an attempt to disseminate research and contribute to social policy. Policy makers have emphasized accountability and now evidence-based practices. Although developmental scholars should be pleased that policy makers want evidence, scholars need to examine the assumptions of evidence-based programming and continue to refine how evidence should be used to decide which services to fund. In addition, we propose a more collaborative strategy to promote evidence-based policies in general

Dispersion in space-time transformation optics

The use of spacetime cloaking to hide events is an intriguing trick, but the unavoidable presence of dispersion limits the performance of any implementation, and needs to be accounted for. We show how the dispersion changes under transformation

Process-based modelling of storm impacts on gravel coasts

Full version unavailable due to 3rd party copyright restrictions.Gravel beaches and barriers occur on many high-latitude, wave-dominated coasts across the world. Due to their natural ability to dissipate large amounts of wave energy, gravel coasts are widely regarded as an effective and sustainable form of coastal defence. However, during extreme events waves may overtop, overwash, and even lower, the crest of the gravel beach, flooding the hinterland. In the evaluation of the safety of gravel coasts against flooding, coastal managers currently rely on models that have been shown in previous studies to be inaccurate. The research in this thesis attempts to improve the current predictive capacity of gravel beach storm response by developing a new process-based model to simulate storm impacts on gravel coasts. The numerical model developed in this thesis, called XBeach-G, is a morphodynamic, depth-averaged, cross-shore profile model, based on the XBeach model for sandy coasts (Roelvink et al., 2009). The model simulates the morphological response of gravel beaches and barriers to storms by solving: (1) intra-wave flow and surface elevation variations using a non-hydrostatic extension of the non-linear shallow water equations; (2) groundwater processes, including infiltration and exfiltration, using a Darcy-Forchheimer-type model; and (3) bed load transport of gravel using a modification of the Van Rijn (2007a) bed load transport equation to include flow acceleration effects, which are shown to be significant on coarse-grained beaches. The model is extensively validated for hydrodynamics, groundwater dynamics and morphodynamics using detailed data collected in physical model experiments, as well as data collected in the field on four natural gravel beaches in the UK and one in France. Validation results show that the model has high quantitative skill in simulating observed hydrodynamics on gravel beaches across a wide range of forcing conditions, in particular with regard to wave transformation, wave run-up and wave overtopping. Spatial and temporal variations in groundwater head are shown to be well represented in the model through comparison to data recorded in a physical model experiment. Validation of the morphodynamic component of XBeach-G shows that the model has high model skill (median BSS 0.75) in simulating storm impacts on five gravel beaches during ten storm events, with observed morphodynamic response ranging from berm-building to barrier rollover. The model is used to investigate hydrodynamic processes on gravel beaches during storms, where it is found that incident-band variance is elemental in the generation of wave run-up on gravel beaches. Furthermore, simulations of wave run-up during high-energy wave events show a distinct disparity between run-up predicted by empirical relations based on the Iribarren parameter and wave steepness, and run-up predicted by XBeach-G, where predictions by the empirical relations substantially underestimate observed wave run-up. Groundwater processes are shown, by means of sensitivity simulations, to strongly affect the morphodynamic response of gravel beaches and barriers to storms. The research in this thesis supports the hypothesis that infiltration in the swash is a key driver for the berm-building response of gravel beaches and helps to reduce erosion of the upper beach during storms. Through model simulations on a schematic gravel barrier it is shown that groundwater processes effectively increases the capacity of gravel barriers to withstand storms with 1-3 m higher surge levels than if groundwater processes did not occur. Reducing the width of a barrier leads to a lowering of this capacity, thereby reducing the resilience of the barrier to extreme storm events. Despite its strong influence on gravel beach morphodynamics, it is found that infiltration plays a relatively small role on wave run-up levels on most natural gravel beaches (median R 2% run-up level reduction of 8%). Application of the model in validation simulations and sensitivity simulations in this thesis, as well as in storm hindcast simulations discussed by McCall et al. (2013) shows the value of using the process-based XBeach-G model in coastal flooding analysis over the use of empirical tools. While no model can be considered entirely accurate, application of XBeach-G in all hindcast overwash simulations has lead to reasonable estimates of overtopping discharge and of morphological change, which is a significant improvement over the frequently substantial errors of the empirical tool designed for this purpose.EPSR

Application of quality by design concepts and automation to improve manufacturing process consistency of development and clinical-stage cell therapies

Designing manufacturing processes to reproducibly generate process-sensitive human cells of sufficient quantity and quality for clinical application is challenging and complex. Manufacture of cell therapies in manual flask based processes is controlled primarily through adherence to detailed SOPs which may contain subjective user interventions and relatively poorly defined operating controls. This situation can lead to clinical production processes with limited control of critical quality attributes, significant reliance on endpoint quality testing and consequent product wastage. Applying systematic and data driven approaches to process development, many of which form part of the Quality by Design (QbD) toolset, reduces manufacturing process risk. We have applied these approaches with a series of partners and cell types to demonstrate application of QbD tools to cell therapies. This includes statistical capability analysis to define process confidence limits for expansion processes, to identify sources of process variability, and to quantify process performance in relation to the process specification and necessary scale. This further enables risk assessment and gap analysis to identify and prioritise key manufacture process risks with common recurrent elements including input materials, cryo-strategy, and operational parameters pertaining to culture and medium supply strategy. Key variable screening via statistically designed experiments has enabled improvement in process consistency across multiple operations and an improved understanding of process tolerance to parameter levels. It also highlights where automation could be applied to enhance process reproducibility and increase process scale whilst retaining process format with comparability to prior manufacturing development. CompacT SelecT automated manufacturing processes have demonstrated consistently greater cell yields than manual processes with statistical analysis showing significantly improved confidence intervals between multiple production batches and facilitating identification of remaining sources of variation for further targeted process improvement. Example case studies include a partnership with ReNeuron, a UK-based stem cell therapy business currently undergoing a phase II clinical trial with its CTX cell therapy candidate to enhance motor recovery in disabled stroke patients, to develop scalable robust production processes for the CTX cell line

THE TIMBER INDUSTRY IN JACKSON COUNTY, NORTH CAROLINA

The purpose of this thesis is to examine the timber industry in Jackson County, North Carolina. It is hoped that the study may also shed light on lumbering in the Appalachian region. By adapting Ronald D Eller's chronology for the economic development of the Appalachian South, the growth of local timber activities will be considered against the backdrop of the regional experience.This study surveys the early history of logging and sawmillinging the county, with special emphasis on the methods and equipment used. The first commercial firm to attempt serious utilization of Jackson County's resources was the Blue Ridge Lumber Company. An account of this company is offered as is one concerning the activities of the Blackwood Lumber Company. The Blackwood Lumber Company was representative of highly mechanized, large-scale commercial operations which developed within western North Carolina in the 1900s.The section dealing with the more recent period centers around Woody Clifton Hennessee and the Mead Corporation. Hennessee is representative of an independent Appalachian lumber entrepreneur,while the Mead Corporation is a major firm operating in the region,but with its headquarters elsewhere. Also, passing attention is given to the independent circular sawmill operators such as Quince Heddon.The thesis shows how the timber industry in Jackson County served as a vehicle for change from a subsistence agricultural society to a wage-oriented one. The timber industry in this county was not as exploitative as in other areas of Appalachia. It has exerted a positive influence here and will undoubtedly do so in the foreseeable future

On spacetime transformation optics:temporal and spatial dispersion

The electromagnetic implementation of cloaking, the hiding of objects from sight by diverting and reassembling illuminating electromagnetic fields has now been with us ten years, while the notion of hiding events is now five. Both schemes as initially presented neglected the inevitable dispersion that arises when a designed medium replaces vacuum under transformation. Here we define a transformation design protocol that incorporates both spacetime transformations and dispersive material responses in a natural and rigorous way. We show how this methodology is applied to an event cloak designed to appear as a homogeneous and isotropic but dispersive medium. The consequences for spacetime transformation design in dispersive materials are discussed, and some parameter and bandwidth constraints identified