1,792 research outputs found

    The electrification of raindrops

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    The charges and masses of individual raindrops were measured in different conditions of rainfall at two different sites. An apparatus was developed to measure raindrop parameters and display their values in the form of a spot whose vertical and horizontal positions on an oscilloscope screen represent the mass and charge respectively. Photographic records, each of a number of successive spots, were made for periods of between half-a-minute and twenty-five minutes during twenty-four separate periods of rainfall which covered many meteorological conditions between thunderstorms and fine drizzle. The photographic results are analysed in terms of the weather conditions applying at the times of measurement. It is shown that stratus and cumulus clouds produce distinct charge/mass patterns on the exposures, and that these patterns can be related to known factors about the nature of the different clouds. The methods of charge measurement by electrostatic induction, and of mass measurement by registering the impacts of drops- on to a detector plate are described. Suggestions are made for future work and improvements to the equipment

    Man of the House : A Turning Point That Leads to Criminal Behavior?

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    This research study seeks to formally test a relationship between household structure, birth order and juvenile delinquency that was suggested as an onset to criminal behavior by men incarcerated in a maximum security facility. The focus of this study is on first born males due to the retrospective narratives given by the incarcerated men that being a first born male who has either lost a father-or father figure due to death, divorce and/or prison have felt a sense of responsibility as the man of house to be able to provide family stability which can include care of other siblings, maintaining the home through housework and in some cases maintaining the family financially. This study tests whether (1) delinquent acts for monetary gain increases if the adolescent is a first born male and (2) delinquency increases if the juvenile first born male is living in a female headed household. I use Sampson and Laub\u27s (1993) life course theory and the NLSY79 to test the hypothesis. Tobit regression models suggests there is no relationship in increased delinquency for monetary gain for first born males and first born males living in a single female headed household

    Fire and Vegetation Dynamics in the Southern Appalachian Mountains

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    Prescribed burn regimes in the forests of the southern Appalachian Mountains have been a topic of research since the revival of fire management in the United states. The presented two studies address two important topics: the viability of long term dormant season burn regimes to reaching management goals, and how the seasonality of prescribed burning may influence sprouting dynamics of target species. The Fire and Fire Surrogate Site at Green River Game Land, Polk County, NC, provided forest structure and compositional data both before and after a 15-year, periodic dormant season burn regime. We found a significant decrease in smaller size class trees after the regime. Secondly, basal area of non-desirable mesophytic hardwoods, such as red maple (Acer rubrum), mountain laurel (Kalmia latifolia), rhododendron (Rhododendron spp.), and blackgums (Nyssa sylvatica), showed a significant decrease as a result of the burn regime. These results imply that if the current regime is to continue, it may result in less mesic, more fire-conducive forests. However, overstory oak abundance also declined significantly during the study period. The abundance of oaks in the midstory did increase in the burn treatment, but the difference was not statistically different from the control. Although periodic dormant season burning may help eliminate mesophytic tree species, future overstory composition may not be comparable to historical conditions. With American chestnut trees absent from the overstory, and hemlocks in decline, it may be unreasonable to think that restoration to historical composition is possible

    A TALE OF TWO CITIES: DIET, HEALTH AND MIGRATION IN POST-MEDIEVAL COVENTRY AND CHELSEA THROUGH BIOGRAPHICAL RECONSTRUCTION, OSTEOARCHAEOLOGY AND ISOTOPE BIOGEOCHEMISTRY

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    Biogeochemical research has over the past four-and-a-half decades improved our understanding of human interaction with past environments. The application of different isotope systems has allowed archaeologists to interpret ancient diet, migration and pollution. Although well established in archaeology, biogeochemical interpretations are burdened with questions not only as to the methodology employed but also whether the data presents a consistent picture of past human activity. The use of biographically identifiable individuals offers a means by which the isotope systems may be tested against extent documentary evidence. A sample of forty-five individuals, almost half of which were named individuals, were obtained from the sites of Holy Trinity (Coventry) and St. Luke's (Old Street, Chelsea) and the stable isotopes of carbon, nitrogen, oxygen, strontium and lead analysed. The biographies ofthe named individuals were reconstructed through analysis ofextant historical documentation and' used to provide a framework of interpretation for the biogeochemical teclmiques applied. Comparisons are made between the two sites in relation to the biogeochemical techniques employed, biographical reconstruction and osteoarchaeological evidence for disease, migration and diet to address methodological issues and broader questions on 'i,ndustrialisation' during the eighteenth and nineteenth centuries. The osteoarchaeological evidence suggests separation of the two groups into discrete' populations, one that is characterised by occupationally-derived osteoarthropathies (Coventry), and the second, Chelsea, which has an absence of these pathologies. This supports the historical character of the t\VO cities: Coventry as an industrial city in contrast to Chelsea, a 'village of palaces' or pleasure resort. Biogeochemically, carbon and nitrogen isotopes revealed a picture of status-based access to protein resources in a diet that is particularly dominated by freshwater fish, terrestrial omnivores such as pig, or a combination of the two. There is, however, little evidence for a difference in access to such resources between the sexes. Likewise, strontium and oxygen isotopes are capable of differentiating between the two populations and therefore in identifying local and migrant individuals, though limitations in the sample prevent the full utilisation of this data. In one case (Milborough Maxwell) the isotopic techniques \vere able to reveal trans-Atlantic migration between England and the Caribbean. Analysis of lead isotopes of the two populations indicates that while there is little to differentiate the two sites, heavy metal exposure is greater for the eighteenth and nineteenth centuries than for previous periods.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Investigation of Environmental Microorganisms Associated with the Intrinsic Microbial Contamination of an Alcohol-Free Mouthwash

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    The United States Pharmacopoeia (USP) Microbial Limits Test and Preservative Effectiveness Test were validated and completed on an alcohol-free mouthwash using standard USP recommended microorganisms and selected organisms isolated from the manufacturing environment. The microbial limits test using environmental isolates was found equivalent to the USP Microbial Limits Test currently used for release of the product. The preservative effectiveness test was performed to determine the efficacy of the parabens system against environmental isolates compared to those recommended in the USP test. In both tests Pseudomonas aeruginosa isolates exhibited resistance to the preservative system. All other isolates failed to grow after week one. Temperature studies conducted with environmental isolates to evaluate sanitation procedures for manufacturing indicated organisms exposed to 70˚C for ten minutes resulted in at least a seven log reduction in number. Environmental isolates exposed to 60˚C and 65˚C were found to survive at these elevated temperatures after a ten minute exposure period

    The development of understanding of selected aspects of pressure, heat and evolution in pupils aged between 12 and 16 years

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    The study is founded on the belief that knowledge based on an individual's prior experience contributes to scientific learning. This is contrasted with a perspective in which it is assumed that concepts have a reality completely independent of the learner. The research is a description of pupils' personal scientific knowledge about several aspects of pressure, heat and evolution. Eighty-four children (aged between 12 and 16 years) were interviewed and asked to give their explanations of scientific problems set in everyday contexts. Categories of response were identified from pupils' words; some of these recurred across different question contexts testing the same scientific concept. They represent frameworks of thought which pupils employ, though they may completely contradict the currently-acceptable scientific notion. Pupil frameworks were identified for the nature of pressure (including a molecular explanation), aspects of fluid pressure, the distinction between heat and temperature, the idea of conduction of heat, aspects of inheritance (including the notion of non-inheritance of acquired characteristics) and for biological adaptation. Their frequencies across three age groups are reported. There was some stability of the frameworks of individual pupils across questions testing the same scientific idea, though the pattern varied from idea to idea. Fifty-eight pupils were re-interviewed after a 20-month interval and the change or stability in thinking of individual pupils was monitored over this period. These results were equivocal. Pupil frameworks relating to some scientific ideas appeared to remain fairly stable overtime, whereas for others pupils drew on different frameworks on the two occasions, frequently on different alternative frameworks. The implications for pedagogy are discussed and it is tentatively suggested that more effective learning might occur if teachers took serious account of pupils' alternative frameworks in their classrooms and laboratories

    Earthworm Abundance Increased by Mob-Grazing Zero-Tilled Arable Land in South-East England

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    © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creative commons.org/licenses/by/4.0/).Regenerative agriculture is a potential alternative to conventional agricultural systems. It integrates the components of zero-tillage, permanent soil cover, diverse crop rotations and rotational or mob-grazing by ruminant livestock. Earthworms are beneficial soil macrofauna and function as indicators of soil health. A need exists to identify how earthworm populations are affected when all four regenerative agriculture components are implemented simultaneously. This study investigates earthworm abundance in three split-plot treatments located on adjacent land within the same farm: (1) ungrazed permanent grassland, (2) a three-year grass-clover ley within an arable zero tillage system without grazing and (3) identical to treatment 2 but with mob-grazing. Earthworms were sampled using soil pits and classified into four functional groups: epigeic (surface dwellers), endogeic (sub-surface), anecic (deep soil) and juveniles. The total earthworm count, epigeic and juvenile functional groups were significantly (p 0.05) higher in treatment (3), the arable zero tillage system with mob-grazing. Mob-grazing increases the diversity of carbon sources available to earthworms and has a positive impact on earthworm abundance and functional group diversity within the arable rotation under evaluation.Peer reviewe
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