Control of Eggplant Yellows.

17 p

Size dependence of volume and surface nucleation rates for homogeneous freezing of supercooled water droplets

The relative roles of volume and surface nucleation were investigated for the homogeneous freezing of pure water droplets. Experiments were carried out in a cryogenic laminar aerosol flow tube using supercooled water aerosols with maximum volume densities at radii between 1 and 3 μm. Temperature- and size-dependent values of volume- and surface-based homogeneous nucleation rates between 234.8 and 236.2 K were derived using a microphysical model and aerosol phase compositions and size distributions determined from infrared extinction measurements in the flow tube. The results show that the contribution from nucleation at the droplet surface increases with decreasing droplet radius and dominates over nucleation in the bulk droplet volume for droplets with radii smaller than approximately 5 μm. This is interpreted in terms of a lowered free energy of ice germ formation in the surface-based process. The implications of surface nucleation for the parameterization of homogeneous ice nucleation in numerical models are considered

A preliminary report on the clays of South Carolina

This book discusses clays of South Carolina including the general characteristics of clays, general geological conditions, classes of clay deposits, varieties of clay, mining of clays, geological occurrence and areal distribution of South Carolina coastal plain clays and physical and chemical properties of South Carolina clays

Development and characterization of a laminar aerosol flow tube

The following article appeared in Review of Scientific Instruments and may be found at https://doi.org/10.1063/1.2175958. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.We have developed a new laminar aerosol flow tube (AFT) to study transformations such as ice nucleation, deliquescence, and efflorescence in model atmospheric aerosols. The apparatus consists of four sections which can be independently cooled to reproduce temperature profiles relevant to the troposphere and stratosphere. An automatic control system maintains the average axial temperature along each section between 100 and 300 K, within ±0.1 K. Changes in aerosol composition, phase, and size distribution are monitored at the tube exit using infrared spectroscopy AFT-IR. We used computational fluid dynamics simulations to investigate flow velocity and temperature distributions within the flow tube. Based on these computations, the final design was formulated to eliminate turbulent mixing zones and buoyancy-driven convection cells. The latter can occur even under conditions where the Reynolds number indicates laminar flow. In either case, recirculation causes aerosol residence times and temperature histories to be poorly defined, leading to erroneous interpretation of experimental measurements. The resulting AFT design used copper fins to reduce temperature gradients and axial mixing of aerosol and carrier gas flows in the inlet section to reduce turbulence. The performance of the new AFT is significantly better than for previous designs.The authors are grateful for the financial support of the Natural Sciences and Engineering Research Council of Canada and the Canadian Foundation for Climate and Atmospheric Studies

Expectant parents' views of factors influencing infant feeding decisions in the antenatal period: A systematic review

Objective: To explore the factors that influence expectant parents’ infant feeding decisions in the antenatal period. Design: Mixed method systematic review focussing on participant views data. Data sources: CINAHL, Medline, Embase and PsychInfo databases were interrogated using initial keywords and then refined terms to elicit relevant studies. Reference lists were checked and hand-searching was undertaken for 2 journals (‘Midwifery’ and ‘Social Science and Medicine’) covering a 3 year time period (January 2011–March 2014). Key inclusion criteria: studies reflecting expectant parents’ views of the factors influencing their infant feeding decisions in the antenatal period; Studies in the English language published after 1990, from developed countries and of qualitative, quantitative or mixed method design. Review methods: A narrative interpretive synthesis of the views data from studies of qualitative, quantitative and mixed method design. Data were extracted on study characteristics and parents’ views, using the Social Ecological Model to support data extraction and thematic synthesis. Synthesis was influenced by the Evidence for Policy and Practice Information and Co-Ordinating Centre approach to mixed method reviews. Results: Of the 409 studies identified through search methods, 17 studies met the inclusion criteria for the review. Thematic synthesis identified 9 themes: Bonding/Attachment; Body Image; Self Esteem/Confidence; Female Role Models; Family and Support Network; Lifestyle; Formal Information Sources; Knowledge; and Feeding in front of others/Public. The review identified a significant bias in the data towards negative factors relating to the breastfeeding decision, suggesting that infant feeding was not a choice between two feeding options, but rather a process of weighing reasons for and against breastfeeding. Findings reflected the perception of the maternal role as intrinsic to the expectant mothers’ infant feeding decisions. Cultural perceptions permeated personal, familial and social influences on the decision-making process. Expectant mothers were sensitive to the way professionals attempted to support and inform them about infant feeding choices. Conclusions: By taking a Social Ecological perspective, we were able to explore and demonstrate the multiple influences impacting on expectant parents in the decision-making process. A better understanding of expectant parents’ views and experiences in making infant feeding decisions in the prenatal and antenatal periods will inform public health policy and the coordination of service provision to support infant feeding activities

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2–4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease