First Principles Calculation of Field Emission from Nanostructures using Time-Dependent Density Functional Theory: a Simplified Approach

We introduce a new simplified method for computing the electron field emission current in short carbon nanotubes using ab-initio computation in periodic simulation cells. We computed the evolution of the wave functions using Time-Dependent Density Functional Theory, where we have utilized the Crank-Nicholson propagator. We found that in pristine carbon nanotubes, the emitted charge tends to emerge mostly from electrons that are concentrated at the nanotube tip region. The charge beam concentrates into specific channel structures, showing the utility of carbon nanotubes in precision emission applications.Comment: Submitted to Physica

Conflict and social vulnerability to climate change: Lessons from Gaza

In societies marred by conflict, the propensity of populations to be harmed by climate hazards is likely to be increased by their exposure to violence and other coercive practices. Stakeholder assessments of climate vulnerability, as reported here for the Gaza Strip, can capture the qualitative experience of harm caused by conflict-related practices as these relate to, and interact with, forecasted climatic risks. The key pathways of climate vulnerability identified by stakeholders in Gaza relate above all to expected impacts on food security and water security. Exploration of these vulnerability pathways reveals conflict-structured non-climatic risks overwhelming forecasted climate risks. The prevalence in Gaza of short-term 'enforced coping' prevents the development of long-term adaptive capacity. Climate vulnerability assessments in (post)conflict environments should acknowledge the methodological and political-policy challenges caused by chronic, non-climatic sources of harm. © 2011 Taylor & Francis

Neonatal immunity: how well has it grown up?

Egypt J Pediatr Allergy Immunol 2003; 1(2): 76-

Weed vegetation ecology of arable land in Salalah, Southern Oman

AbstractThis paper applies multivariate statistical methods to a data set of weed relevés from arable fields in two different habitat types of coastal and mountainous escarpments in Southern Oman. The objectives were to test the effect of environmental gradients, crop plants and time on weed species composition, to rank the importance of these particular factors, and to describe the patterns of species composition and diversity associated with these factors. Through the application of TWINSPAN, DCA and CCA programs on data relating to 102 species recorded in 28 plots and farms distributed in the study area, six plant communities were identified: I- Dichanthium micranthum, II- Cynodon dactylon–D. micranthum, III- Convolvulus arvensis, IV- C. dactylon–Sonchus oleraceus, V- Amaranthus viridis and VI- Suaeda aegyptiaca–Achyranthes aspera. The ordination process (CCA) provided a sequence of plant communities and species diversity that correlated with some anthropogenic factors, physiographic variables and crop types. Therefore, length of time since farm construction, disturbance levels and altitude are the most important factors related to the occurrence of the species. The perennial species correlated with the more degraded mountain areas of new farm stands, whereas most of the annuals correlated with old lowland and less disturbed farms

Population structure of woody plants in the arid cloud forests of Dhofar, southern Oman

This study evaluates the size frequency distribution of 11 trees and shrubs in the cloud forest in Wadi Garziz, southern Oman, in order to assess their current situation, which is affected by cutting, overgrazing and other constraints. A size class distribution and a vegetation structure analysis were applied in order to analyze the dynamics of this forest using census data from 51 plots selected across 5 transects covering the hill-slope andwadi-bed habitats. Some of the trees inhabiting the hill-slopes (e.g. Acacia senegal and Commiphora spp.) were found to exhibit an inverse J-shaped distribution with constant regeneration, whilst in the wadi bed these same trees exhibited a J-shaped distribution (i.e. of declining populations). On the other hand, Acacia etbaica inhabiting the hill- slopes exhibited a tendency towards a J-shaped distribution and an inverse J-shaped distribution in the wadi-bed. All the populations (i.e. inhabiting the hill-slopes and the beds) of Anogeissus dhofarica had a J-shaped distribution whereas all the populations of Blepharispermum hirtum had a more or less inverse J-shaped distribution. The Ziziphus spina-christi and Acacia tortilis populations, meanwhile, exhibited the bi-modal shape of size distribution. The shrubs inhabiting the hill-slopes (e.g. Coroton confertus and Ormocarpum dhofarense) exhibited a tendency towards a J-shaped distribution; such distribution characterizes a declining population with a limited regenerational capacity. Overall, most of the examined populations, except those of Acacia etbaica in wadi-bed and Blepharispermum hirtum, seemed to be under stress from both environmental and human factors, particularly in the wadi bed. This type of study can provide a basis for the development of a management plan to support the conservation and sustainable use of forest vegetation in an arid region

Disarming With Humor

Attending an academic advising meeting can be a challenge for students who either do not know what to expect during the advising process or fear that it will be a difficult exchange with the advisor. This article highlights a scenario of a reluctant student and explores how academic advisors can make their students comfortable and begin to foster connection with their students through humor. The article examines how humor can be intentionally infused into the Appreciative Advising framework specifically in the initial Disarm phase which is focused on helping academic advisors build rapport and trust with their students

Efficiency of using Arabic Gum and Plantago Seeds Mucilage as Edible Coating for Chicken Boneless Breast

Edible coatings are an environmentally friendly technology that is applied on many food products to provide and protect food quality.  The objective of this work is to use Arabic Gum and Plantago seeds mucilage at concentration (15, 20 and 25% w/v) as edible coating for chicken breast to prolong its shelf life at 4 ?C. Coated samples produced the optimum deceases in pH, TBA, total bacterial count and enhanced the sensory attributes compered to untreated chicken breast. Samples treated with 25% Plantago showed the lowest value of TBA of 0.141mg malondialdehyde.kg-1 compared to 0.38mg malondialdehyde.kg-1 in control after 21 days of storage. Whereas, 25% Arabic gum was the most effective in reducing total bacterial count from 25×106 cfu.g-1 in control to 0.8×102 cfu.g-1. This study suggests that Arabic gum and plantago seeds mucilage showed a potential role in delaying chicken boneless breast spoilage. Keywords: Edible coating, Arabic Gum, Plantago seeds, Boneless chicken breast

Calibration Estimation for Ratio Estimators in Stratified Sampling for Proportion Allocation

Calibration has established itself as an important methodological instrument in large scale production of statistics. In this paper, we propose calibration estimation for ratio estimator in stratified sampling and derive the estimator of the variance of the calibration estimation ratio estimator in stratified sampling in case proportion allocation