2,395 research outputs found
Supersymmetric exact sequence, heat kernel and super KdV hierarchy
We introduce the free N=1 supersymmetric derivation ring and prove the
existence of an exact sequence of supersymmetric rings and linear
transformations. We apply necessary and sufficient conditions arising from this
exact supersymmetric sequence to obtain the essential relations between
conserved quantities, gradients and the N=1 super KdV hierarchy. We combine
this algebraic approach with an analytic analysis of the super heat operator.We
obtain the explicit expression for the Green's function of the super heat
operator in terms of a series expansion and discuss its properties. The
expansion is convergent under the assumption of bounded bosonic and fermionic
potentials. We show that the asymptotic expansion when of the Green's
function for the super heat operator evaluated over its diagonal generates all
the members of the N=1 super KdV hierarchy.Comment: 20 pages, to be published in JM
Cascading the use of Web 2.0 technology in secondary schools in the United Kingdom: identifying the barriers beyond pre-service training
This paper reports on research that took place at Nottingham Trent University and Sheffield Hallam University, United Kingdom, over two years. The research focuses on the use of Web 2.0 technology, specifically web logs, with pre-service teachers, both during their university programme and the first year of teaching as full-time newly qualified teachers (NQTs). The purpose of this research was to add a developing body of knowledge by identifying whether technology used by pre-service teachers during their training course can be cascaded into their practice once qualified. Key findings identify a number of enablers and barriers to cascading technology in the classroom; these include curriculum time, pupil skills and support. The research concludes that early professional support and development should be on-going and assumptions about new teachers as champions of cascading innovative use of Web 2 technologies into their practice as NQTs may be over optimisti
Pharmacokinetics of Trazodone and Its Major Metabolite M-Chlorophenylpiperazine in Plasma and Brain of Rats
Sprague–Dawley rats were used as models for single trazodone administration (males), continuous administration and dose proportionality experiments (males, females, pregnant females). Plasma and brain tissue were analysed for trazodone and its active metabolite, m-chlorophenylpiperazine (m-CPP). Fetal exposure to trazodone and m-CPP was assessed and differences in their steady-state plasma concentration were sought between adult males and females. Both trazodone and m-CPP rapidly appeared in plasma and brain tissue following a single intraperitoneal trazodone dose with brain concentrations exceeding those in plasma. Plasma concentrations of m-CPP were lower than those of trazodone but exceeded them in brain tissue. Chronic administration using osmotic mini-pumps revealed a significant linear relationship between trazodone concentration in plasma and brain at steady-state (r=0.96, p\u3c0.0001). No simple relationship was found between plasma and brain tissue concentration for m-CPP. In contrast to observations following single trazodone administration, m-CPP concentrations at steady-state were lower than trazodone concentrations in brain tissue, suggesting a lack of stationarity in the disposition of trazodone over time. No significant differences in plasma or brain tissue drug concentrations relative to administered trazodone dose were observed between male and female rats, nor between pregnant and non-pregnant females. Trazodone and mCPP were both detected in fetal and placental tissues, with placenta having the highest concentrations. The data suggest that neuropharmacological studies of trazodone could yield different results depending upon the route and schedule of drug administration. Maternally administered trazodone, like many other antidepressants, is distributed to fetal tissues in rodents, reaffirming the need for caution in treating pregnant women with psychoactive drugs
Hygienic practices and diarrheal illness among persons living in at-risk settings in Kabul, Afghanistan: a cross-sectional study
Abstract
Background
Sustained civil and military conflict, resulting in large numbers of internally displaced persons (IDP), in combination with rapid urbanization has strained public health and sanitation within cities in Afghanistan. In order to examine the association between preventive sanitary behaviors and diarrhea within two high risk settings located within Kabul, Afghanistan, this study aimed to evaluate the prevalence of hygienic practices and diarrheal illness in an IDP camp and an urban slum.
Methods
In this cross sectional study, a convenience sample of residents of an IDP camp and an urban slum in Kabul, Afghanistan, was used. Participants were asked to describe their hygienic practices and interviewers independently documented household sanitation. The knowledge and attitudes about and practice of hygienic activities to prevent diarrhea were compared between the two settings.
Results
Two hundred participants, 100 from each setting, were enrolled. Knowledge, attitudes, and practices regarding hygienic activities to prevent diarrhea were greater among the slum dwellers than the IDP. Fewer than half of participants washed their hands with soap before eating or after eating: 31 % of slum dwellers washed before eating compared to 11 % of IDPs (P = 0.0050), and 25 % of slum dwellers washed after defecating compared to 4 % of IDPs (P = 0.0020). The IDPs were more likely to share a latrine (P = 0.0144) and less likely to disinfect their latrine than slum dwellers. Diarrhea in the household within the past 3 months was more common in the IDP camp (54 %) than the slum (20 %) (P = 0.0020).
Conclusions
Even though certain sanitary and hygienic practices were more common among slum dwellers than IDPs, the lack of hygienic activities in both setting indicates that interventions to change behavior, like increasing the availability of soap and encouraging hand washing, are needed. Any initiative will have to be developed in the context of pervasive illiteracy among persons in both of these settings.http://deepblue.lib.umich.edu/bitstream/2027.42/134634/1/12879_2016_Article_1789.pd
Development of Stresses in Cohesionless Poured Sand
The pressure distribution beneath a conical sandpile, created by pouring sand
from a point source onto a rough rigid support, shows a pronounced minimum
below the apex (`the dip'). Recent work of the authors has attempted to explain
this phenomenon by invoking local rules for stress propagation that depend on
the local geometry, and hence on the construction history, of the medium. We
discuss the fundamental difference between such approaches, which lead to
hyperbolic differential equations, and elastoplastic models, for which the
equations are elliptic within any elastic zones present .... This displacement
field appears to be either ill-defined, or defined relative to a reference
state whose physical existence is in doubt. Insofar as their predictions depend
on physical factors unknown and outside experimental control, such
elastoplastic models predict that the observations should be intrinsically
irreproducible .... Our hyperbolic models are based instead on a physical
picture of the material, in which (a) the load is supported by a skeletal
network of force chains ("stress paths") whose geometry depends on construction
history; (b) this network is `fragile' or marginally stable, in a sense that we
define. .... We point out that our hyperbolic models can nonetheless be
reconciled with elastoplastic ideas by taking the limit of an extremely
anisotropic yield condition.Comment: 25 pages, latex RS.tex with rspublic.sty, 7 figures in Rsfig.ps.
Philosophical Transactions A, Royal Society, submitted 02/9
Timely measles vaccination in Tianjin, China: a cross-sectional study of immunization records and mothers
Abstract
Background
Measles is a highly infectious disease, and timely administration of two doses of vaccine can ensure adequate protection against measles for all ages in a population. This study aims to estimate the proportion of children aged 8 months to 6 years vaccinated on time with measles-containing vaccines (MCV) and vaccinated during the 2008 and 2010 measles supplementary immunization activities. This study also characterizes differences in mean age at vaccination and vaccination timeliness by demographic characteristics, and describes maternal knowledge of measles vaccination.
Methods
Immunization records were selected from a convenience sample of immunization clinics in Tianjin, China. From the records, overall vaccination coverage and timely vaccination coverage were calculated for different demographic groups. Mothers were also interviewed at these clinics to ascertain their knowledge of measles vaccination.
Results
Within the 329 immunization clinic records, child’s birth year and district of residence were found to be significant predictors of different measures of vaccine timeliness. Children born in 2009 had a lower age at MCV dose 2 administration (17.96 months) than children born in 2005 (22.00 months). Children living in Hebei, a district in the urban center of Tianjin were less likely to be vaccinated late than children living in districts further from the urban core of Tianjin. From the 31 interviews with mothers, most women believed that timely vaccination was very important and more than one dose was very necessary; most did not know whether their child needed another dose.
Conclusions
When reviewing MCV coverage in China, most studies do not consider timeliness. However, this study shows that overall vaccination coverage can greatly overestimate vaccination coverage within certain segments of the population, such as young infants.http://deepblue.lib.umich.edu/bitstream/2027.42/109549/1/12889_2014_Article_6997.pd
pyveg: A Python package for analysing the time evolution of patterned vegetation using Google Earth Engine
Periodic vegetation patterns (PVP) arise from the interplay between forces that drive the
growth and mortality of plants. Inter-plant competition for resources, in particular water,
can lead to the formation of PVP. Arid and semi-arid ecosystems may be under threat due
to changing precipitation dynamics driven by macroscopic changes in climate. These regions
display some noteable examples of PVP, for example the “tiger bush” patterns found in West
Africa.
The morphology of the periodic pattern has been suggested to be linked to the resilience of
the ecosystem (Mander et al., 2017; Trichon et al., 2018). Using remote sensing techniques,
vegetation patterns in these regions can be studied, and an analysis of the resilience of the
ecosystem can be performed.
The pyveg package implements functionality to download and process data from Google Earth
Engine (GEE), and to subsequently perform a resilience analysis on the aquired data. PVP
images are quantified using network centrality metrics. The results of the analysis can be
used to search for typical early warning signals of an ecological collapse (Dakos et al., 2008).
Google Earth Engine Editor scripts are also provided to help researchers discover locations of
ecosystems which may be in decline.
pyveg is being developed as part of a research project looking for evidence of early warning
signals of ecosystem collapse using remote sensing data. pyveg allows such research to be
carried out at scale, and hence can be an important tool in understanding changing arid and
semi-arid ecosystem dynamics. An evolving list of PVP locations, obtained through both
literature and manual searches, is included in the package at pyveg/coordinates.py. The
structure of the package is outlined in Figure 1, and is discussed in more detail in the following
sections
Ten years of a multidisciplinary diabetic foot team approach in Sao Paulo, Brazil
Diabetes mellitus can cause devastating foot problems including loss of protective sensation with subsequent ulcerations and amputations. The natural history and pathophysiology of diabetic foot ulcers is best understood and managed by a multiprofessional team approach. The main factors for prevention and treatment of these devastating diabetic foot conditions are shown, with special attention to education of the patient. This approach decreases the morbidity of the disease, besides its economical and social feasibility
International Health Regulations—What Gets Measured Gets Done
Focus on goals and metrics for 4 core capacities illustrates 1 approach to implementing IHR
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