Simulation of hurricane response to suppression of warm rain by sub-micron aerosols

The feasibility of hurricane modification was investigated for hurricane Katrina using the Weather Research and Forecasting Model (WRF). The possible impact of seeding of clouds with submicron cloud condensation nuclei (CCN) on hurricane structure and intensity as measured by nearly halving of the area covered by hurricane force winds was simulated by "turning–off" warm rain formation in the clouds at Katrina's periphery (where wind speeds were less than 22 m s<sup>−1</sup>). This simplification of the simulation of aerosol effects is aimed at evaluating the largest possible response. This resulted in the weakening of the hurricane surface winds compared to the "non-seeded" simulated storm during the first 24 h within the entire tropical cyclone (TC) area compared to a control simulation without warm rain suppression. Later, the seeding-induced evaporative cooling at the TC periphery led to a shrinking of the eye and hence to some increase in the wind within the small central area of the TC. Yet, the overall strength of the hurricane, as defined by the area covered by hurricane force winds, decreased in response to the suppressed warm rain at the periphery, as measured by a 25% reduction in the radius of hurricane force winds. In a simulation with warm rain suppression throughout the hurricane, the radius of the hurricane force winds was reduced by more than 42%, and although the diameter of the eye shrunk even further the maximum winds weakened. This shows that the main mechanism by which suppressing warm rain weakens the TC is the low level evaporative cooling of the un-precipitated cloud drops and the added cooling due to melting of precipitation that falls from above

Functional Heterogeneity of Immune Complexes in Epidermolysis Bullosa Acquisita

Epidermolysis bullosa acquisita is an inflammatory subepidermal bullous disease characterized by circulating and tissue-bound complement-binding anti-basement membrane zone autoantibodies to type VII procollagen. Lesions are characterized by neutrophil-predominant inflammation in some patients, but not in others. These features suggest complement activation and generation of complement-derived chemotactic factors for leukocytes by basement membrane zone immune complexes may contribute to inflammation, but that complexes may be heterogeneous in the ability to express that function. In this study, we measured the ability of basement membrane zone complexes from patients with (n = 4) and without (n = 6) neutrophil predominant inflammation to activate complement and generate complement-derived chemotactic activity using a complement-dependent neutrophil attachment assay. The results showed considerable heterogeneity in neutrophil attachment among EBA patients and that both the incidence (4/4 vs 2/6) and magnitude (81 +/- 34 vs 12 +/- 10 neutrophils/mm basement membrane zone) of attachment were greater in patients with neutrophil-predominant inflammation. Functional heterogeneity appeared to be due to differences in the amounts of complement-activating complexes formed at the basement membrane zone, which in turn appeared to be due to differences in the availability of circulating complement-binding anti-basement membrane zone antibodies. This was suggested by a positive correlation (r = 0.72, p less than 0.01) between neutrophil attachment and complement-binding anti-basement membrane zone antibody titers and the observation that high levels of neutrophil attachment could be generated in skin from patients with epidermolysis bullosa acquisita who did not have neutrophil-predominant inflammation by treating their skin in vitro with complement-binding anti-basement membrane zone antibodies. These results suggest tissue complexes in epidermolysis bullosa acquisita are heterogeneous in the ability to activate complement and generate complement-derived chemotactins (C5a, C5a des arg), and that functional heterogeneity contributes to histologic heterogeneity. The functional immunologic-pathologic correlations observed in this study suggest epidermolysis bullosa acquisita is an autoimmune "collagen" disease

Hindcasting of hurricane characteristics and observed storm damage on a fringing reef, Jamaica, West Indies

Hurricane Allen is one of the most severe hurricanes on record and caused extensive damage throughout the Caribbean in early August 1980. Coral reefs along the north coast of Jamaica were devastated by the hurricane-induced waves. As in the case of most hurricanes, no wave measurements were made. We have computed the wind field and hindcast the deep water wave characteristics as the storm impacted the fringing reef at Discovery Bay on the north central coast of Jamaica. The deep water waves propagated into shallow water on the forereef and transformed as a result of shoaling and refraction. We found that significant wave height at a given time varied by a factor of 2.6 and that incident wave power for the duration of the storm varied by a factor of 7 along a 3 km section of the Discovery Bay forereef due to variations in local bathymetry. Maximum hindcast breakers reached a height of 11.5 m with a significant wave period of 10.5 s. Observations of the most intense reef damage coincided with areas on the eastern forereef experiencing the highest breakers. We speculate that the degree of reef damage is a function of how much time has elapsed since the previous storm rather than frequency of hurricanes at a locality

<i>‘What retention’ means to me</i>: the position of the adult learner in student retention

Studies of student retention and progression overwhelmingly appear adopt definitions that place the institution, rather than the student, at the centre. Retention is most often conceived in terms of linear and continuous progress between institutionally identified start and end points. This paper reports on research that considered data from 38 in-depth interviews conducted with individuals who had characteristics often associated with non-traditional engagement in higher education who between 2006 and 2010 had studied an ‘Introduction to HE’ module at one distance higher education institution, some of whom had progressed to further study at that institution, some of whom had not. The research deployed a life histories approach to seek a finer grained understanding of how individuals conceptualise their own learning journey and experience, in order to reflect on institutional conceptions of student retention. The findings highlight potential anomalies hidden within institutional retention rates – large proportions of the interview participants who were not ‘retained’ by the institution reported successful progression to and in other learning institutions and environments, both formal and informal. Nearly all described positive perspectives on lifelong learning which were either engendered or improved by the learning undertaken. This attests to the complexity of individuals’ lives and provides clear evidence that institution-centric definitions of retention and progression are insufficient to create truly meaningful understanding of successful individual learning journeys and experiences. It is argued that only through careful consideration of the lived experience of students and a re-conception of measures of retention, will we be able to offer real insight into improving student retention

Not All Children with Cystic Fibrosis Have Abnormal Esophageal Neutralization during Chemical Clearance of Acid Reflux.

PurposeAcid neutralization during chemical clearance is significantly prolonged in children with cystic fibrosis, compared to symptomatic children without cystic fibrosis. The absence of available reference values impeded identification of abnormal findings within individual patients with and without cystic fibrosis. The present study aimed to test the hypothesis that significantly more children with cystic fibrosis have acid neutralization durations during chemical clearance that fall outside the physiological range.MethodsPublished reference value for acid neutralization duration during chemical clearance (determined using combined impedance/pH monitoring) was used to assess esophageal acid neutralization efficiency during chemical clearance in 16 children with cystic fibrosis (3 to &lt;18 years) and 16 age-matched children without cystic fibrosis.ResultsDuration of acid neutralization during chemical clearance exceeded the upper end of the physiological range in 9 of 16 (56.3%) children with and in 3 of 16 (18.8%) children without cystic fibrosis (p=0.0412). The likelihood ratio for duration indicated that children with cystic fibrosis are 2.1-times more likely to have abnormal acid neutralization during chemical clearance, and children with abnormal acid neutralization during chemical clearance are 1.5-times more likely to have cystic fibrosis.ConclusionSignificantly more (but not all) children with cystic fibrosis have abnormally prolonged esophageal clearance of acid. Children with cystic fibrosis are more likely to have abnormal acid neutralization during chemical clearance. Additional studies involving larger sample sizes are needed to address the importance of genotype, esophageal motility, composition and volume of saliva, and gastric acidity on acid neutralization efficiency in cystic fibrosis children

A Mouse Monoclonal Antibody Against a Newly Discovered Basement Membrane Component, the Epidermolysis Bullosa Acquisita Antigen

A mouse monoclonal antibody, H3a, directed against the newly described epidermolysis bullosa acquisita (EBA) antigen was obtained using hybridoma techniques. The distribution of the monoclonal antibody is identical to that of the polyclonal serum antibody of patients with EBA. By immunofluorescence, a linear band is seen at the dermal-epidermal junction and, by immunoelectron microscopy, immune reaction products are present in the lamina densa and sublamina densa regions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by Western immunoblot analysis shows that the monoclonal antibody recognizes 290 and 145 kilodalton proteins present in the immunizing junctional extract, identical with the newly discovered EBA antigen. This monoclonal antibody should be useful in the further isolation and characterization of the EBA antigen