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Search Results: 1 - 10 of 6099 matches for " Samuel; "
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Investigating the Distribution of Selected Major and Trace Metals in Lithogenic Environment near Cement Factory, Mekelle, Ethiopia  [PDF]
Samuel Estifanos
Journal of Environmental Protection (JEP) , 2014, DOI: 10.4236/jep.2014.52018
Abstract:

Sixteen physicochemical parameters including four major and ten trace metals were analyzed for seven top soil and six top stream sediment samples collected around the vicinity of cement factory in Mekelle, Ethiopia. Water and aqua regia extraction techniques were deployed to determine the water soluble and near total concentration of the metals in the samples. Water extraction results verified the magnitude of loading of the metals from anthropogenic sources. The mean values of the water soluble metals are found to exceed the reference values except for Ca and Zn in both lithogenic media indicating the severity of pollution. Spatial distribution of the metals suggested that cement factory dust and traffic emissions represent the most important pollutant sources for the investigated area.  The mean proportion of the major and trace metals in the water soluble phase of soil can be put on a descending order as: Mg (57.76%) > Fe > Ca > K > Na > Mn (3.77%) and Mo (53.17%) > Cu > Co > As > Ni > Zn > Pb

Assessing the Relative Efficiency of Health Systems in Sub-Saharan Africa Using Data Envelopment Analysis  [PDF]
Samuel Ambapour
American Journal of Operations Research (AJOR) , 2015, DOI: 10.4236/ajor.2015.51003
Abstract: We assess the relative efficiency of health systems of 35 countries in sub-Saharan Africa using Data Envelopment Analysis. This method allows us to evaluate the ability of each country to transform its sanitary “inputs” into health “outputs”. Our results show that, on average, the health systems of these countries have an efficiency score between 72% and 84% of their maximum level. We also note that education and density of population are factors that affect the efficiency of the health system in these countries.
Block Unification Scheme for Elliptic, Telegraph, and Sine-Gordon Partial Differential Equations  [PDF]
Samuel Jator
American Journal of Computational Mathematics (AJCM) , 2015, DOI: 10.4236/ajcm.2015.52014
Abstract: In this paper, we use the method of lines to convert elliptic and hyperbolic partial differential equations (PDEs) into systems of boundary value problems and initial value problems in ordinary differential equations (ODEs) by replacing the appropriate derivatives with central difference methods. The resulting system of ODEs is then solved using an extended block Numerov-type method (EBNUM) via a block unification technique. The accuracy and speed advantages of the EBNUM over the finite difference method (FDM) are established numerically.
The Todaro Paradox: An Econometric Test Using Data from Congo  [PDF]
Samuel Ambapour
Modern Economy (ME) , 2015, DOI: 10.4236/me.2015.68083
Abstract: In this paper we test on data from Congo, what is come to know as Todaro Paradox. That is, on the one hand, the idea is put forward by Lewis that, industrial expansion will allow developing countries to reduce unemployment caused by an oversized rural workforce. However, on the other hand, Harris and Todaro argue that expanding urban employment will attract the rural population into the cities thus increasing unemployment. Our result seems to confirm Lewis’ theory that urban job creation leads to lower unemployment.
A Note Regarding Prioritization on Congestible Networks  [PDF]
Samuel Raisanen
Theoretical Economics Letters (TEL) , 2015, DOI: 10.4236/tel.2015.55071
Abstract: This paper examines the effect of allowing prioritization of traffic on a congestible network under three demand scenarios. First, it is shown that when prioritization does not affect usage, average congestion on the network increases. Second, this result is shown to hold when there is demand shifting toward the prioritized network service but no impact on total network traffic. Finally, it is proven that for prioritization to reduce average congestion on a network it must reduce the total traffic on the network.
Measuring Employment Inertia in a Period of Crisis: An Interpretation of Brechling Short-Run Model  [PDF]
Samuel Ambapour
Theoretical Economics Letters (TEL) , 2017, DOI: 10.4236/tel.2017.74064
Abstract: In this paper, the Brechling model is used to measure employment inertia in five sectors of the Congolese economy between 1983 and 1993. During that period, the Congolese economy found itself at a crossroad. On the one hand, the implementation of the 1982-1986 five-year economic development plans involved considerable infrastructure investment. On the other hand, given the market reversal observed since 1985, the infrastructure funding and the tempo became less. A structural adjustment program had to be undertaken with the World Bank in 1987-1989 with its measures entirely designed to restore the country’s macroeconomic balance and to enable it to resume regular and sustainable growth over time. Thus, the result from the short-run employment model taken over the period in question demonstrates that there is strong employment inertia in the sectors investigated.
The Need for Structural Adjustment: Was It Essential for African Countries over the Decade of the 80’s? An Econometric Analysis Using Count Data Models  [PDF]
Samuel Ambapour
Open Journal of Statistics (OJS) , 2017, DOI: 10.4236/ojs.2017.74041
Abstract:
Several economists agree to say that the need for adjustment was essential for African countries over the decade of the 80’s. The econometric analysis of a sample of 28 sub-Saharan African countries, from variables regarded as “representatives” for the adjustment objectives, proves that this assertion cannot be completely rejected.
Intestinal Obstruction Due to an Internal Hernia through a Defect of the Broad Ligament in an Adult Female Patient: Case Report and Literature Review  [PDF]
Samuel A. Essoun, Samuel Debrah
International Journal of Clinical Medicine (IJCM) , 2014, DOI: 10.4236/ijcm.2014.513109
Abstract:

Internal hernia is a rare cause of intestinal obstruction. We present a case of 43-year-old woman without any prior surgical history who was referred as a case of obstructed para-umbilical hernia from a satellite clinic. The objective is to highlight the occurrence of such a rare clinical problem and to provide an insight into decision making especially when there is discordance between an obvious pathology and clinical features.

Ionization and transfection activity of n-methyl-substituted carbamoyl-cholesterol derivatives  [PDF]
Samuel Acheampong, Michalakis Savva
Journal of Biophysical Chemistry (JBPC) , 2011, DOI: 10.4236/jbpc.2011.22008
Abstract: Five novel cationic lipids, the polar head group of which was attached to the cholesterol backbone via a tertiary carbamate linker, were synthesized and their physicochemical properties were compared to their transfection efficiencies. Transfection activity of the primary amine analog was highest among the series, while the quaternary ammonium iodide salt was essentially transfection incompetent. Contrary to DC-Chol, methyl and ethyl carbamoyl derivatives of DC-Chol mediated high levels of transfection in the absence of DOPE. Ionization of the cationic assemblies in 40 mM Tris buffer pH 7.2 exactly correlated with the competitive nature of the inductive and steric effects of the methyl groups on the aliphatic nitrogen of the lipids’ polar moiety. Interestingly, the pH interaction zone of all lipid dispersions at 25°C was extended by ± 2 pH units from the pKa, while the pKa of the cationic lipids determined in mixed vesicles composed of 90 % DOPC and cholesterol was approximately 1.3 to 1.5 times higher than that of pure cationic assemblies. The interaction of cationic lipids with plasmid DNA was correlated with pKa, but not the transfection activity.
Economic and Social Impact of Tourism on a Small Town: Peterborough New Hampshire  [PDF]
Tomoko Tsundoda, Samuel Mendlinger
Journal of Service Science and Management (JSSM) , 2009, DOI: 10.4236/jssm.2009.22009
Abstract: This study examined the perceived impacts of tourism on the lives of people from a small New England town. Twenty seven in-depth unstructured interviews were conducted. The study found that most people perceive both positive and negative impacts of tourism and do not want to change their town for increased tourism development even if it results in increased revenue. People recognized tourism’s benefit to the town’s economy but less so to their economic situation. Working locals expressed worry regarding the town’s gradually polarized economy and divided social classes and regard tourism as one of the causes. Wealthier members generally view tourism at its present level as beneficial. For further tourism development Peterborough’ population will need to solve this dilemma.
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