3,305 research outputs found
A pictorial record of the program of waterfront activities at Agassiz Village, an organizational type boys' camp in West Poland, Maine.
Thesis (M.Ed.)--Boston University
78 Kadachrome slides accompany thesis and may be found in the Audio-visual Library.
N.B. Table of contents says summary is on page 18 but it is found on page 14
Financial Performance of Organic Cattle Farming
FFI/ha on organic cattle rearing farms was 56% higher than on conventional farms due entirely to lower costs of production (€240/ha v €640/ha). However the organic farms were selected as monitor farms and therefore represent the better producers whilst the conventional farms were selected at random. Output and direct payments per ha were higher on conventional farms but not sufficient to cover the additional costs. Organic farms were 24% larger than conventional farms. Organic drystock cattle producers had a more viable socio-economic profile, whilst technical performance was higher on the conventional farms. Organic dairy farms had 7% higher farm income over conventional dairy farmers in 2007. However, these data are based on a small sample and should therefore be interpreted with caution
III-V Solar Cells
III-V materials show a wide range of gaps making them ideal for the design of
high efficiency solar cells. This chapter reviews relevant growth methods and
material properties of these materials and discusses methods of combining
heterogeneous materials, demonstrating the flexibility of design possible with
these materials. The fundamental loss mechanisms of solar cells are analysed
and quantified as a prelude to analysing high efficiency cell designs in
single, tandem, and triple junction solar cells. The detailed analysis of loss
mechanisms is used to obtain understanding of the limiting behaviour of these
designs, and show that bulk cells remain dominated by non-radiative losses
despite unity ideality factors. To conclude, this is contrasted with the
operating regime of nanostructured solar cells which can be shown to operate in
a radiatively dominated mode, and which therefore approach ideal solar cell
efficiency limits.Comment: Draft of chapter in Materials Challenges: Inorganic Photovoltaic
Solar Energy - RSC Energy and Environment Series v. 1
When and where? Pathogenic Escherichia coli differentially sense host D-serine using a universal transporter system to monitor their environment
Sensing environmental stimuli is critically important for bacteria when faced with the multitude of adversities presented within the host. Responding appropriately to these signals and in turn integrating these responses into the regulatory network of the cell allows bacteria to control precisely when and where they should establish colonization. D-serine is an abundant metabolite of the human urinary tract but is a toxic metabolite for Escherichia coli that lack a D-serine tolerance locus. Enterohaemorrhagic E. coli (EHEC) cannot catabolize D-serine for this reason and colonize the large intestine specifically, an environment low in D-serine. EHEC can however use D-serine sensing to repress colonization thus signaling the presence of an unfavorable environment. In our recent work (Connolly, et al. PLoS Pathogens (2016) 12(1): e1005359), we describe the discovery of a functional and previously uncharacterized D-serine uptake system in E. coli. The genes identified are highly conserved in all E. coli lineages but are regulated differentially in unique pathogenic backgrounds. The study identified that EHEC, counter-intuitively, increase D-serine uptake in its presence but that this is a tolerated process and is used to increase the transcriptional response to this signal. It was also found that the system has been integrated into the transcriptional network of EHEC-specific virulence genes, demonstrating an important pathotype-specific adaptation of core genome components
The surgery obstruction groups of the infinite dihedral group
This paper computes the quadratic Witt groups (the Wall L-groups) of the
polynomial ring Z[t] and the integral group ring of the infinite dihedral
group, with various involutions. We show that some of these groups are infinite
direct sums of cyclic groups of order 2 and 4. The techniques used are
quadratic linking forms over Z[t] and Arf invariants.Comment: Published by Geometry and Topology at
http://www.maths.warwick.ac.uk/gt/GTVol8/paper29.abs.htm
The highly conserved Escherichia coli transcription factor YhaJ regulates aromatic compound degradation
The aromatic compound 2,4-dinitrotoluene (DNT), a common impurity in 2,4,6-trinitrotoluene (TNT) production, has been suggested as a tracer for the presence of TNT-based landmines due to its stability and high volatility. We have previously described an Escherichia coli bioreporter capable of detecting the presence of DNT vapors, harboring a fusion of the yqjF gene promoter to a reporter element. However, the DNT metabolite which is the direct inducer of yqjF, has not yet been identified, nor has the regulatory mechanism of the induction been clarified. We demonstrate here that the YhaJ protein, a member of the LysR type family, acts as a transcriptional regulator of yqjF activation, as well as of a panel of additional E. coli genes. This group of genes share a common sequence motif in their promoters, which is suggested here as a putative YhaJ-box. In addition, we have linked YhaJ to the regulation of quinol-like compound degradation in the cell, and identified yhaK as playing a role in the degradation of DNT
Tracking elusive cargo: Illuminating spatio-temporal type 3 effector protein dynamics using reporters
Type 3 secretion systems (T3SS) form an integral part of the arsenal of many pathogenic bacteria. These injection machines, together with their cargo of subversive effector proteins are capable of manipulating the cellular environment of the host in order to ensure persistence of the pathogen. In order to fully appreciate the functions of Type 3 effectors it is necessary to gain spatio-temporal knowledge of each effector during the process of infection. A number of genetic modifications have been exploited in order to reveal effector protein secretion, translocation and subsequent activity and localisation within host cells. In this review, we will discuss the many available approaches for tracking effector protein dynamics and discuss the challenges faced to improve the current technologies and gain a clearer picture of effector protein function
Doctors and Drinkers: An Exploratory Study of the Therapeutic Commitment of General Practioners in Longford/Westmeath towards working with Problem Drinkers
Alcohol and alcohol related problems are the major public health issues in
Ireland and in many other countries in the Western World. In Ireland, and
internationally health policy makers have promoted the public health
perspective on alcohol problems, incorporating a community response, an
emphasis on primary care, and an active role for general practitioners in
working with problem drinkers. The rationale for the involvement of general
practitioners in this work is underpinned by a range of factors. The most
important of these, are the reconceptualization of alcohol problems as a broad
spectrum disorder, the evidence that patients with alcohol problems visit thengeneral
practitioner more often than other patients, and the evidence for the
relative effectiveness of brief interventions, by general practitioners in
comparison to intensive specialist services.
A number of barriers, both attitudinal and organizational have been identified,
that affect the involvement of general practitioners with problem drinkers.
Research evidence suggests that general practitioners have what is called low
therapeutic commitment towards working with drinkers, because of lack of
counselling skills, knowledge, experience and support. The purpose of this
exploratory study, was to establish the level of therapeutic commitment of 35
general practitioners, members of the Irish College of General Practitioners in
Longford/Westmeath towards working with problem drinkers using the AAPPQ
questionnaire (Cartwright 1978). The general practitioners were found to have
low therapeutic commitment towards working with problem drinkers.
Paradoxically the respondents felt they had the right to engage drinkers (role
legitimacy) and that they had the knowledge and skills (role adequacy) to carry
out this work. Despite expressed feelings of role adequacy, respondents were
found to have limited experience, training, education, and support in relation
to alcohol problems. It is suggested that general practitioners need education
training and support, in order to increase their therapeutic commitment towards
working with problem drinkers. However the structural and situational
constraints under which they work, represent major barriers to general
practitioners receiving this education and trainin
Affectivity and job satisfaction: a meta-analysis
The goal of this investigation was to examine the affective determinants of job satisfaction. Correlations between affectivity and job satisfaction measures were examined by cumulating research findings across studies. Measurement of affectivity in this study focused on five constructs, (1) negative affectivity, (2) positive affectivity, (3) affective disposition, (4) positive & negative affectivity, (5) all affectivity measures combined. The correlations between these five constructs and job satisfaction were meta-analyzed. The mean correlation corrected for coefficient alpha in both the affectivity and job satisfaction measures were: .49 for positive affectivity (N= 3,326, k= 15), -. 33 for negative affectivity (N= 6,028, k= 25), .36 for affective disposition (N= 1,415, k= 7), .39 for positive & negative affectivity (N= 9,354, k= 40), and .38 for all measures of affectivity combined (N= 10,769, k= 47). Results indicated that 10% - 25% of variance in job satisfaction could be due to individual differences in affectivity. No strong moderator variables were found. Implications for a Dispositional and situational source of job satisfaction are discussed
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Curriculum planning in community colleges and the emerging technological economy.
This study examined curriculum planning strategies at four Massachusetts community colleges: Massachusetts Bay Community College, Bunker Hill Community College, Roxbury Community College and Middlesex Community College. This examination was done through an interview process conducted throughout 1990. The interviewees were three knowledgeable officials at each of the four community colleges. The interviews were conducted in person and lasted approximately two hours each. It was the goal of the interview process to have interviewers respond to a number of questions related to the planning strategies used currently in the context of curriculum development, labor force preparation, and the emerging technological economy and questions related to planning strategies being contemplated for the future in the context of curriculum development, labor force preparation and the emerging technological economy. The data from these qualitative interviews were summarized, analyzed, and compared. Additionally, this study gathered data from five-year plans of each community college. Points stressed by those interviewed were compiled in the section on Findings . From the Findings, conclusions were drawn relative to the subject of this dissertation. It is interesting to note that while many might not fully have appreciated the reality, community colleges are now and will likely continue to be significantly involved in remediation as a component of their respective missions
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