5,431 research outputs found

    Condensation risk: comparison of steady-state and transient methods

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    Accurate assessment of both surface and interstitial condensation risk is important not only to reduce the damaging effect of moisture within the structure of buildings, but also to provide a healthy environment free from mould growth. The current British Standard (BS EN ISO 13788: 2002) contains an assessment procedure based on the assumption of a steady-state heat flow through the building envelope, neglecting the transient nature of the problem. This paper compares and evaluates numerical results of the condensation risk calculation under both steady-state and transient conditions using the existing numerical codes. Significant differences are apparent between the predictions of the simple (steady-state) and complex (transient) methods for all construction details modelled

    The Perspective of School Personnel in a Georgia School District Concerning the Recruitment of Minority Teachers

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    Recruiting and attracting minorities into the teaching profession is difficult. Given the competitiveness of the current job market and the heavy emphasis on standardized testing for all teacher candidates, the difficulties of attracting quality minority teachers are becoming more challenging. The lack of a racially and culturally diverse teaching staff remains a major issue in education nationally and locally, especially since projections indicate that the representation of minority teachers is declining while the number of minority students is increasing. This need for more minority teachers is even more critical in urban public schools characterized by large percentages of minority students and rural hard-to-staff schools. The purpose of the study was to identify effective recruitment strategies used to recruit minority teachers. The researcher utilized qualitative methodology for this study. The study was a single case study. The research examined recruitment initiatives used by a school district utilizing interview questions administered to a select population of school and district level personnel. The participants of the study were individuals who had the authority to speak about the recruitment and selection of minority teachers in their district that included the human resource director, a school board member, and the principal of an elementary school, a middle school, and a high school from the same Georgia public school district. The results of the interviews were examined for the similarities and differences in the recruitment initiatives for minority teachers as perceived by the participants. The interviews were recorded and transcribed by the researcher and the data organized, classified, and developed by themes. Several themes emerged from these interviews. It is important to recruit minority teachers because they serve as positive role models. However, participants focused on hiring the most qualified candidate regardless of race/ethnicity. The second prevailing theme was that no specific policies are in place regarding the recruitment of ethnic and minority teachers. The third theme was that a computerized recruitment system seemed to be the most effective recruitment instrument. Other strategies used to recruit minority teachers in the district included word of mouth, job fairs, and participation in the TAPP program. Therefore, recommendations from this study included, the school district conduct a similar study to determine if all principals are aware of and are using the tools at their disposal for recruiting and retaining minority teachers, the school district solicit best practices each year from principals who have successfully recruited minority teachers, the human resource department publishes an annual report on the school district website that depicts hiring patterns of each school in the district, and the human resource department provide annual reports to members of the board of education with the number of teachers and students in each school by racial and ethnic backgrounds

    Increasing vertical mixing to reduce Southern Ocean deep convection in NEMO3.4

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    Most CMIP5 (Coupled Model Intercomparison Project Phase 5) models unrealistically form Antarctic Bottom Water by open ocean deep convection in the Weddell and Ross seas. To identify the mechanisms triggering Southern Ocean deep convection in models, we perform sensitivity experiments on the ocean model NEMO3.4 forced by prescribed atmospheric fluxes. We vary the vertical velocity scale of the Langmuir turbulence, the fraction of turbulent kinetic energy transferred below the mixed layer, and the background diffusivity and run short simulations from 1980. All experiments exhibit deep convection in the Riiser-Larsen Sea in 1987; the origin is a positive sea ice anomaly in 1985, causing a shallow anomaly in mixed layer depth, hence anomalously warm surface waters and subsequent polynya opening. Modifying the vertical mixing impacts both the climatological state and the associated surface anomalies. The experiments with enhanced mixing exhibit colder surface waters and reduced deep convection. The experiments with decreased mixing give warmer surface waters, open larger polynyas causing more saline surface waters and have deep convection across the Weddell Sea until the simulations end. Extended experiments reveal an increase in the Drake Passage transport of 4 Sv each year deep convection occurs, leading to an unrealistically large transport at the end of the simulation. North Atlantic deep convection is not significantly affected by the changes in mixing parameters. As new climate model overflow parameterisations are developed to form Antarctic Bottom Water more realistically, we argue that models would benefit from stopping Southern Ocean deep convection, for example by increasing their vertical mixing

    Seeing social enterprise through the theoretical conceptualisation of ethical capital

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    Objectives: Current conceptualisations of social enterprise fail to fully satisfy an understanding of the movement. A focus on the economic implies a business model where deep tensions lie. A focus on social capital offers a different frame of reference, yet both these conceptualisations fail to fully identify the phenomena that is social enterprise. The objective of this paper seeks to fill that gap. Ethical capital is offered here as the missing conceptualisation in the field of social enterprise. Prior work: Pearce (2003) describes social enterprises as part of the third system, closer to the first system (private business), than the second system (public provision), yet primarily social and secondly a business. Social Enterprises are described as trading organisations in a market (Pearce 2003). A focus and operationalisation for social enterprises to be ‘business-like’ and ‘entrepreneurial’ is well documented (Leadbeater 1997; Dees 1998; Nicholls 2006b). Approach: Yet, if as part of the third sector, social enterprises are as Dart (2004) suggests; ‘blurring the boundaries between non-profit and profit’, but what blurs? What is compromised? What exactly is lost (or gained)? What challenges are there for social enterprises? And is a managerialist ideology taking precedence over the social? This paper provides a conceptual paper that seeks to outline the arguments on the table and develop an ethical capital conceptualisation of social enterprise. Results: This paper very much aims at starting the process of intellectual debate about the notion of ethical capital in social enterprises. The conclusions of this paper outline further research questions that need to be addressed in order to fully develop this concept. Implications: The current ideology of the neo-classical economic paradigm it is argued in the paper pursues interests towards the self and towards the erosion of the moral basis of association. The outcome leaves society with a problem of low ethical virtue - the implications of this paper are that social enterprises maximise ethical virtue beyond any other form of organisation and as such hold great value beyond their missions and values. Value: This paper offers great value in the understanding of social enterprise through fresh insight into the conceptualisation. A critical perspective to the current literature is taken and discussed but though the introduction of ethical capital this paper takes our understanding of the value of the sector into another light, providing practitioners, business support agencies and academics alike with a different level of conceptualisation that has not been explored before.</p

    An evaluation of the hygrothermal performance of 'standard' and 'as built' construction details using steadystate and transient modelling

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    Accurate assessment of both surface and interstitial condensation risk at the design stage of buildings is of great importance - not just to minimise the damaging effects moisture can cause to building envelopes, but also to contribute to the provision of adequate indoor air quality. Guidance certainly does exist with regards to limiting thermal bridging in order to prevent condensation occurring on new constructions. However, a recent study has provided clear evidence that the reality, both in translating the available guidance into a specific design and in construction on site is often rather different from the 'ideal'. This paper reports on that study and compares and evaluates the hygrothermal performance of construction details for different phases during the building life cycle. The results of both the surface and interstitial condensation risk simulations under both steady-state and transient conditions are presented and discussed. Significant differences in the hygrothermal performance of 'standard' and 'as built' construction details are observed

    An initial evaluation of a biohygrothermal model for the purpose of assessing the risk mould growth in UK dwellings

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    Moulds are organisms that may be found in both the indoor and outdoor environment. Moulds play an important rolebreaking down and digesting organic material, but, if they are significantly present in the indoor environment they mayaffect the health of the occupants. A relative humidity of 80% at wall surfaces is frequently stated as the decisivecriterion for mould growth and methods used to assess the risk of mould growth are often based on steady stateconditions. However, considering the dynamic conditions typically found in the indoor environment, a betterunderstanding of the conditions required for mould to grow would seem desirable. This paper presents initialexploratory work to evaluate and assess ‘WUFI-bio’ - ‘biohygrothermal’ software that predicts the likelihood of mould growth under transient conditions. Model predictions are compared with large monitored data set from 1,388 UKdwellings before and after insulation and new heating systems are installed (‘Warm Front’), the suitability of thissoftware as a tool to predict mould growth will ultimately be assessed. This paper presents some initial, exploratorywork

    What moderates the attainment gap? The effects of social identity incompatibility and practical incompatibility on the performance of students who are or are not Black, Asian or Minority Ethnic

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    A successful journey through higher education is, for many, a once in a lifetime opportunity for social mobility. Unfortunately, one notable feature of higher education systems is that students from some backgrounds do not achieve the same academic attainments as do others. The current study tests the role of one particular set of processes: social identity (in)compatibility on academic performance. Participants were recruited at two time points from a pool of first year undergraduates at a modern London University (N=215) of which 40.1% were classed as Black, Asian or Minority Ethnic (BAME), 57.1% as non-BAME and 2.8% did not provide this information. A prospective design was employed: Alongside demographic data, measures at the start of the academic year consisted of measures of student and ethnic identity, and both practical and identity incompatibility. At the end of the academic year, average marks achieved were gained for each student from the university’s registry system. Results indicate that BAME students had equal levels of student identity to non-BAME students, but higher levels of ethnic identity. They also typically experienced higher levels of both practical and identity incompatibility. Finally, BAME students had lower attainment than did non-BAME students. Both practical and identity incompatibility appeared to moderate this effect. However, contrary to predictions, it was only under conditions of low and medium levels of incompatibility that BAME students attained lower marks than their non-BAME peers. The theoretical and practical implications of these findings are discussed

    Analysis of particulate emissions from tropical biomass burning using a global aerosol model and long-term surface observations

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    We use the GLOMAP global aerosol model evaluated against observations of surface particulate matter (PM₂⋅₅) and aerosol optical depth (AOD) to better understand the impacts of biomass burning on tropical aerosol over the period 2003 to 2011. Previous studies report a large underestimation of AOD over regions impacted by tropical biomass burning, scaling particulate emissions from fire by up to a factor of 6 to enable the models to simulate observed AOD. To explore the uncertainty in emissions we use three satellite-derived fire emission datasets (GFED3, GFAS1 and FINN1). In these datasets the tropics account for 66-84% of global particulate emissions from fire. With all emission datasets GLOMAP underestimates dry season PM₂⋅₅ concentrations in regions of high fire activity in South America and underestimates AOD over South America, Africa and Southeast Asia. When we assume an upper estimate of aerosol hygroscopicity, underestimation of AOD over tropical regions impacted by biomass burning is reduced relative to previous studies. Where coincident observations of surface PM₂⋅₅ and AOD are available we find a greater model underestimation of AOD than PM₂⋅₅, even when we assume an upper estimate of aerosol hygroscopicity. Increasing particulate emissions to improve simulation of AOD can therefore lead to overestimation of surface PM₂⋅₅ concentrations. We find that scaling FINN1 emissions by a factor of 1.5 prevents underestimation of AOD and surface PM₂⋅₅ in most tropical locations except Africa. GFAS1 requires emission scaling factor of 3.4 in most locations with the exception of equatorial Asia where a scaling factor of 1.5 is adequate. Scaling GFED3 emissions by a factor of 1.5 is sufficient in active deforestation regions of South America and equatorial Asia, but a larger scaling factor is required elsewhere. The model with GFED3 emissions poorly simulates observed seasonal variability in surface PM₂⋅₅ and AOD in regions where small fires dominate, providing independent evidence that GFED3 underestimates particulate emissions from small fires. Seasonal variability in both PM₂⋅₅ and AOD is better simulated by the model using FINN1 emissions. Detailed observations of aerosol properties over biomass burning regions are required to better constrain particulate emissions from fires

    Bursting emission from PSR B0611+22

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    Over the past decade it has become apparent that a class of `bursting pulsars\u27 exist with the discovery of PSR J1752+2359 and PSR J1938+2213. In these pulsars, a sharp increase in the emission is observed that then tends to systematically drop-off from pulse-to-pulse. In this paper we describe the discovery of such a relationship in high-sensitivity observations of the young (characteristic age of 90,000 yrs) 0.33 s pulsar B0611+22 at both 327 MHz and 1400 MHz with the Arecibo radio telescope. While Nowakowski previously showed that B0611+22 has mode-switching properties, the data presented here show, for the first time, that this pulsar emits bursts with characteristic time-scales of several hundred seconds. At 327 MHz, the pulsar shows steady behaviour in one emission mode which is enhanced by bursting emission slightly offset in pulse phase from this steady emission. Contrastingly at 1400 MHz, the two modes appear to behave in a competing operation while still offset in phase. Using a fluctuation spectrum analysis, we also investigate each mode independently for sub-pulse drifting. Neither emission mode (i.e. during bursts or persistent emission) shows the presence of the drifting sub-pulse phenomenon. The bursting phenomena seen here appears to be a hybrid between bursting seen in other pulsars and the bistable profile illumination behaviour reported in two other pulsars by Rankin et al. Further examples of this cross-frequency behaviour are required, as this phenomenon may be quite common among the pulsar population
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