First quasi-elastic polarized electron scattering measurement of polarization transfer to protons in a complex nucleus: Oxygen-16

The first polarization transfer measurement in the (e,e\u27 p) reaction on a complex nucleus, a study of the exclusive reaction O16e&ar; ,e\u27p&ar; 15N* , is discussed in this thesis. This experiment was performed at Jefferson Lab, using the Hall A Focal Plane Polarimeter. This was the first experiment to use polarized beam at Jefferson Lab. Simultaneous measurements were also made for the He&ar;, e\u27p&ar; reaction allowing a precise comparison between the form factor ratios for free and bound protons. Since the helicity-dependent, longitudinal P\u27l and transverse P\u27t components of the polarization of the recoil proton are sensitive to the electromagnetic form factors GE and GM of the proton inside the nuclear medium, these polarization transfer observables can be used to look for possible medium modification effects on the form factor ratio for the bound proton. The systematic uncertainties involved in performing a recoil polarimetry measurement are minimal, and the theoretical uncertainty (mainly corrections to the Impulse Approximation) are also small. Therefore this measurement provides a sensitive test of the predictions of medium-induced changes in the form factor ratio. Results were obtained for two recoil momentum points, 85 and 140 MeV/c, at a Q2 of 0.8 (GeV/c)2 in quasielastic, perpendicular kinematics. Within statistical uncertainties, the results are in good agreement with theoretical calculations for the polarization observables obtained assuming free values for the form factors, i.e., the results are consistent with the absence of medium modifications of the nucleon electromagnetic structure. This experiment provides a strong basis for the forthcoming high precision measurements of the ratio GE/GM in the nuclear medium

The pion parton distribution function in the valence region

The parton distribution function of the pion in the valence region is extracted in a next-to-leading order analysis from Fermilab E-615 pionic Drell-Yan data. The effects of the parameterization of the pion's valence distributions are examined. Modern nucleon parton distributions and nuclear corrections were used and possible effects from higher twist contributions were considered in the analysis. In the next-to-leading order analysis, the high-$x$ dependence of the pion structure function differs from that of the leading order analysis, but not enough to agree with the expectations of pQCD and Dyson-Schwinger calculations.Comment: 5 pages, 4 figures, submitted to Phys. Rev.

A Paradise with Waste: A Case Study of the Polluter Pays Principle into the Human-Made Environmental Pollution by Waste with Special Reference to Chunnakam Decision and Bulankulama Phosphate Decision

Chunnakam Decision is marking a milestone of the judicial engagement in protecting the natural environment from pollutants by delivering progressive interpretation for the international environmental law principles such as polluter pays principle. In the decision, the supreme court observed the pollution made by the thermal station to the groundwater of Chunnakam area and made groundwater unfit for human use. On the other hand, in the decision of Bulankulama phosphate case, the supreme court emphasised the importance of having Environmental Impact Assessment (EIA) to ensure environmentally sound and sustainable of prescribed projects by the developers. This research, therefore, intends to analyse these two major judiciary pronouncements, Bulankulama phosphate case and the Chunnakam themerl power station Case by focusing of the application of international environmental law principles of sustainable development and polluter pays principles. Further, to explore how could these international environmental law principles utilise to overcome the problems relating to waste management and the pollution in Sri Lanka. The methodology of the research is a qualitative research conducted concerning primary sources such as International conventions, declarations, national and international legislation, and case law; and secondary sources such as international standard-setting documents reports issued by international and national environmental agencies, texts of academic authority and existing research studies.Keywords: Waste management, pollution control, international environmental law, sustainable development, the polluter pays principl

Water barrier properties of carboxymethyl cellulose/halloysite nanotubes nanocomposite to be used in food packaging applications

In this research, novel carboxymethyl cellulose (CMC) based nanocomposite film containing 5%wt of halloysite nanotubes (HNT) was fabricated via solvent casting method as a potential biodegradable packaging material. The performances of the nanocomposite packaging material was investigated by assessing the moisture content, moisture uptake, water solubility, water vapor barrier properties and opacity. The incorporation of 5%wt HNT into the film remarkably reduced the moisture uptake by ∼ 28.01% at 97% RH and 31.08% at 40% RH. Water permeability value of CMC/HNT film showed as 7.08 ± 0.26 × 10−11 gm/m2Pas at freezing, 3.37 ± 0.33 × 10−11 gm/m2Pas at refrigeration and 1.14 ± 0.00 × 10−11 gm/m2Pas at ambient environmental conditions respectively. Subsequent to the thermal annealing process, the water vapor permeation ability was drastically declined in the HNT added nanocomposite films at all three different conditions (freezing, refrigeration and ambient) due to enhancing the crystalline structure. Furthermore, the addition of nanofillers into the polymer matrix significantly induced the UV blocking property of the film. These findings disclosed that prepared CMC/5%HNT nanocomposite films can be a potential food packaging material.Keywords: barrier properties, carboxy methyl cellulose, halloysite nanotube

Family-centered rounds and medical student performance on the NBME pediatrics subject (shelf) examination: a retrospective cohort study

Objective To determine the association between family-centered rounds (FCR) and medical student knowledge acquisition as assessed by the National Board of Medical Examiners (NBME) pediatric subject (shelf) exam. Methods A retrospective cohort study was conducted of third-year medical students who graduated from Virginia Commonwealth University School of Medicine between 2009 and 2014. This timeframe represented the transition from ‘traditional’ rounds to FCR on the pediatric inpatient unit. Data collected included demographics, United States Medical Licensing Examination (USMLE) Step 1 and 2 scores, and NBME subject examinations in pediatrics (PSE), medicine (MSE), and surgery (SSE). Results Eight hundred and sixteen participants were included in the analysis. Student performance on the PSE could not be statistically differentiated from performance on the MSE for any year except 2011 (z-score=−0.17, p=0.02). Average scores on PSE for years 2009, 2010, 2013, and 2014 were significantly higher than for SSE, but not significantly different for all other years. The PSE was highly correlated with USMLE Step 1 and Step 2 examinations (correlation range 0.56–0.77) for all years. Conclusions Our results showed no difference in PSE performance during a time in which our institution transitioned to FCR. These findings should be reassuring for students, attending physicians, and medical educators

Forms of Formative Assessment in Virtual Learning Environments

One of the challenges in the contemporary education is improving learner’s learning capability during the learning period through formative assessment in virtual learning environments. The formative assessment process requires learner to be active participants in the learning process by communicating and interacting with the instructor. The formative assessment process accommodates learner responses that give an opportunity to support the learner in learning through feedback. In a virtual learning environment, formative assessment can be significantly improved by the use of information systems. In this research we explore forms of formative assessment in virtual leaning environments with a specific focus on the design dimension. Our analysis improves the understanding of formative assessment and the design dimension specific to forms of formative assessment in virtual learning environments. Our work informs the design of online learning environments to improve the effectiveness of formative assessment

Multi-Dimensional Views for Sustainability: Ontological Approach

Sustainability has been assessed by measuring the environmental, social and economic performance. Such diverse measurements could include contrasting attributes in sustainability measures namely environmental, social, and economic attributes. Our research argues that it is necessary to use a multi-dimensional approach for sustainability knowledge improvements that consist of all sustainability dimensions. Ontology models the real world and is useful in understanding different dimensions of a phenomenon. The use of an appropriate ontology such as static, dynamic, social, and intentional ontologies help to better understand the sustainability dimensions - environmental, social, and economic. This research develops ontology-based multi-dimensional view to environmental management by focusing on sustainability. The research uses hypothetical situations to develop ontological views and maps the ontological knowledge onto the sustainability dimensions to develop knowledge. This approach integrates information systems and environmental research, while encouraging multi-dimensional approaches for improved knowledge

Polarization measurements in high-energy deuteron photodisintegration

We present measurements of the recoil proton polarization for the d(γ⃗,p⃗)n reaction at θ_(c.m.) = 90° for photon energies up to 2.4 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. The induced polarization p_y vanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transfer C_x does not vanish above 1 GeV, inconsistent with hadron helicity conservation. Thus, we show that the scaling behavior observed in the d(γ,p)n cross sections is not a result of perturbative QCD. These data should provide important tests of new nonperturbative calculations in the intermediate energy regime

Case study on community involvement in rural water supply Sri Lanka

Millennium Development goals create new vision to achieve current development issues in developing countries. In Sri Lanka there are various constraints to providing safe water and sanitation to the entire population. Sustainability of rural water supply systems is an acute problem mainly due to the adopted supply driven approach. To change this, the Ministry of Urban Development and Water Supply Sri Lanka, together with Asian Development Bank was given responsibility by the National Water Supply & Drainage Board to formulate a project focusing on sustainability. As a result a Project was designed based on a people centred and demand driven approach. Objectives of this approach are : to induce a sense of owner-ship; to reduce capital and O&M costs through community participation; and to achieve sustainability. ADB Assisted Third Water Supply and Sanitation (Sector) Project was implemented with a view of achieving the above objectives This paper describes the positive and negative impacts of community involvement in this Project