Ohio's Contribution to Meteorology, a Brief Historical Resume

Author Institution: Department of Physics and Astronomy, The Ohio State University, Columbus 1

Acid droplet generation in SRM exhaust clouds

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76858/1/AIAA-1983-2615-428.pd

Ammonium sulfate crystallization in Andersen cascade impactor samples

Meteorologists are accustomed to the atmospheric phase changes of water. It is observed that phase changes ending with crystallization and crystal growth of (NH4)2SO4 take place in Andersen Samplers used to collect size-stratified samples of airborne particles. It is not at this point clear whether preformed (NH4)2SO4 crystals of small size are involved, although this is likely, but the cascade impaction processes evidently play a role in generating large (NH4)2SO4 crystals on the last few stages of these samplers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22246/1/0000682.pd

The relationship between the macro- and microclimate

A search of the literature has yielded a very small number of papers dealing with quantitative relationships between the macro- and microclimate. Such relationships would be of great value in view of the difficulty in obtaining microclimatological measurements and of their limited application. It is suggested that useful relationships are possible.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32030/1/0000073.pd

Topological Defects, Orientational Order, and Depinning of the Electron Solid in a Random Potential

We report on the results of molecular dynamics simulation (MD) studies of the classical two-dimensional electron crystal in the presence disorder. Our study is motivated by recent experiments on this system in modulation doped semiconductor systems in very strong magnetic fields, where the magnetic length is much smaller than the average interelectron spacing $a_0$, as well as by recent studies of electrons on the surface of helium. We investigate the low temperature state of this system using a simulated annealing method. We find that the low temperature state of the system always has isolated dislocations, even at the weakest disorder levels investigated. We also find evidence for a transition from a hexatic glass to an isotropic glass as the disorder is increased. The former is characterized by quasi-long range orientational order, and the absence of disclination defects in the low temperature state, and the latter by short range orientational order and the presence of these defects. The threshold electric field is also studied as a function of the disorder strength, and is shown to have a characteristic signature of the transition. Finally, the qualitative behavior of the electron flow in the depinned state is shown to change continuously from an elastic flow to a channel-like, plastic flow as the disorder strength is increased.Comment: 31 pages, RevTex 3.0, 15 figures upon request, accepted for publication in Phys. Rev. B., HAF94MD

A Longitudinal 6-Year Study of the Molecular Epidemiology of Clinical Campylobacter Isolates in Oxfordshire, United Kingdom

Temporal and seasonal trends in Campylobacter genotypes causing human gastroenteritis were investigated in a 6-year study of 3,300 recent isolates from Oxfordshire, United Kingdom. Genotypes (sequence types [ST]) were defined using multilocus sequence typing and assigned to a clonal complex (a cluster of related strains that share four or more identical alleles with a previously defined central genotype). A previously undescribed clonal complex (ST-464) was identified which, together with ST-42, ST-45, and ST-52 complexes, showed increasing incidence. Concurrently, the incidence of ST-574, ST-607, and ST-658 complexes declined. The relative frequencies of three clonal complexes (ST-45, ST-283, and ST-42) peaked during summer and those of two (ST-353 and ST-403) peaked during winter. Nine clonal complexes (ST-22, ST-45, ST-48, ST-61, ST-257, ST-283, ST-403, ST-658, and ST-677) were significantly associated with ciprofloxacin sensitivity (P < 0.05). Seven clonal complexes (ST-49, ST-206, ST-354, ST-446, ST-460, ST-464, and ST-607) were associated with ciprofloxacin resistance (P < 0.05). Clonal complexes exhibited changing incidence and differences in seasonality and antibiotic resistance phenotype. These data also demonstrated that detailed surveillance at a single site captures information which reflects that observed nationally

Identification of a novel zinc metalloprotease through a global analysis of clostridium difficile extracellular proteins

Clostridium difficile is a major cause of infectious diarrhea worldwide. Although the cell surface proteins are recognized to be important in clostridial pathogenesis, biological functions of only a few are known. Also, apart from the toxins, proteins exported by C. difficile into the extracellular milieu have been poorly studied. In order to identify novel extracellular factors of C. difficile, we analyzed bacterial culture supernatants prepared from clinical isolates, 630 and R20291, using liquid chromatography-tandem mass spectrometry. The majority of the proteins identified were non-canonical extracellular proteins. These could be largely classified into proteins associated to the cell wall (including CWPs and extracellular hydrolases), transporters and flagellar proteins. Seven unknown hypothetical proteins were also identified. One of these proteins, CD630_28300, shared sequence similarity with the anthrax lethal factor, a known zinc metallopeptidase. We demonstrated that CD630_28300 (named Zmp1) binds zinc and is able to cleave fibronectin and fibrinogen in vitro in a zinc-dependent manner. Using site-directed mutagenesis, we identified residues important in zinc binding and enzymatic activity. Furthermore, we demonstrated that Zmp1 destabilizes the fibronectin network produced by human fibroblasts. Thus, by analyzing the exoproteome of C. difficile, we identified a novel extracellular metalloprotease that may be important in key steps of clostridial pathogenesis

Group Singing as a Resource for the Development of a Healthy Public

A growing body of evidence points to a wide range of benefits arising from participation in group singing. Group singing requires participants to engage with each other in a simultaneous musical dialogue in a pluralistic and emergent context, creating a coherent cultural expression through the reflexive negotiation of (musical) meaning manifest in the collective power of the human voice. As such, group singing might be taken – both literally and figuratively – as a potent form of ‘healthy public’, creating an ‘ideal’ community which participants can subsequently mobilise as a positive resource for everyday life. The experiences of a group of singers (n=78) who had participated in an outdoor singing project were collected and analysed using a three-layer research design consisting of: distributed data generation and interpretation, considered against comparative data from other singing groups (n=88); a focus group workshop (n=11); an unstructured interview (n=2). The study confirmed an expected perception of the social bonding effect of group singing, highlighting affordances for interpersonal attunement and attachment alongside a powerful individual sense of feeling ‘uplifted’. This study presents a novel perspective on group singing, highlighting the importance of participant experience as a means of understanding music as a holistic and complex adaptive system. It validates findings about group singing from previous studies - in particular the stability of the social bonding effect as a less variant characteristic in the face of environmental and other situational influences, alongside its capacity for mental health recovery. It establishes a subjective sociocultural and musical understanding of group singing, by expanding on these findings to centralise the importance of individual experience, and the consciousness of that experience as descriptive self-awareness. The ways in which participants describe and discuss their experiences of group singing and its benefits points to a complex interdependence between a number of musical, neurobiological and psychosocial mechanisms which might be independently and objectively analysed. An emerging theory is that at least some of the potency of group singing is as a resource where people can rehearse and perform ‘healthy’ relationships, further emphasising its potential as a resource for healthy publics

Habitat-related birdsong divergence: a multi-level study on the influence of territory density and ambient noise in European blackbirds

Song plays an important role in avian communication and acoustic variation is important at both the individual and population level. Habitat-related variation between populations in particular can reflect adaptations to the environment accumulated over generations, but this may not always be the case. In this study, we test whether variation between individuals matches local conditions with respect to noise level and territory density to examine whether short-term flexibility could contribute to song divergence at the population level. We conducted a case study on an urban and forest population of the European blackbird and show divergence at the population level (i.e. across habitats) in blackbird song, anthropogenic noise level and territory density. Unlike in several other species, we found a lack of any correlation at the individual level (i.e. across individuals) between song features and ambient noise. This suggests species-specific causal explanations for noise-dependent song differentiation which are likely associated with variation in song-copying behaviour or feedback constraints related to variable singing styles. On the other hand, we found that at the level of individual territories, temporal features, but not spectral ones, are correlated to territory density and seasonality. This suggests that short-term individual variation can indeed contribute to habitat-dependent divergence at the population level. As this may undermine the potential role for song as a population marker, we conclude that more investigations on individual song flexibility are required for a better understanding of the impact of population-level song divergence on hybridisation and speciation

Seasonal and Ontogenetic Changes in Movement Patterns of Sixgill Sharks

Understanding movement patterns is fundamental to population and conservation biology. The way an animal moves through its environment influences the dynamics of local populations and will determine how susceptible it is to natural or anthropogenic perturbations. It is of particular interest to understand the patterns of movement for species which are susceptible to human activities (e.g. fishing), or that exert a large influence on community structure, such as sharks.We monitored the patterns of movement of 34 sixgill sharks Hexanchus griseus using two large-scale acoustic arrays inside and outside Puget Sound, Washington, USA. Sixgill sharks were residents in Puget Sound for up to at least four years before making large movements out of the estuary. Within Puget Sound, sixgills inhabited sites for several weeks at a time and returned to the same sites annually. Across four years, sixgills had consistent seasonal movements in which they moved to the north from winter to spring and moved to the south from summer to fall. Just prior to leaving Puget Sound, sixgills altered their behavior and moved twice as fast among sites. Nineteen of the thirty-four sixgills were detected leaving Puget Sound for the outer coast. Three of these sharks returned to Puget Sound.For most large marine predators, we have a limited understanding of how they move through their environment, and this clouds our ability to successfully manage their populations and their communities. With detailed movement information, such as that being uncovered with acoustic monitoring, we can begin to quantify the spatial and temporal impacts of large predators within the framework of their ecosystems