Agriculture and gender roles in the semi-arid region of Ghana

In the Upper East Region (UER) of Ghana, women play an important role in economic growth and poverty reduction through their active engagement in agricultural activities. However, little is known about the extent of their productive roles in agriculture in the region. This study sought to investigate the gender-specific agricultural roles of men and women in the region where the major livelihood is subsistence rain-fed agriculture. A household survey was conducted from August to December 2014 using a pre-tested questionnaire where 150 males and 150 female headed households (HH) were randomly sampled from 14 communities within the Bolgatanga Municipality and Bongo district of UER. The simple Fisher’s exact test using STATA 13 statistical software was used to determine the correlation between gender and agreement or disagreement in productive roles. Results show that women are involved at all levels of farming activities particularly in physically demanding activities such as planting crops, weeding, fertilizer application, tree and crop harvesting among others. Women are not engaged in financial administration except for selling of crops. Men on the other hand, are responsible for land preparation, feeding of livestock, seedling production among others. Planting of crops and harvesting of fruit trees are performed jointly by men and women. About 86 % of men and 94 % of women perceived planting of crops to be a productive task that should be performed jointly, whereas 65 % men and 65 % women expressed the same view on harvesting of fruits. There is a need to empower women through policy formulation and enforcement to allow them equal access to productive resources such as land

Appearance of Negative Differential Conductivity in Graphene Nanoribbons at High-Harmonics

We theoretically study current dynamics of graphene nanoribbons subject to bias dc and ac driven fields. We showed that graphene nanoribbons exhibit negative high-harmonic differential conductivity. Negative differential conductivity appears when bias electric filed is in the neighborhood of applied ac filed amplitude. We also observe both even and odd high-harmonic negative differential conductivity at wave mixing of two commensurate frequencies. The even harmonics are more pronounced than the odd harmonics. A possible use of the present method for generating terahertz frequencies at even harmonics in graphene is suggested.Comment: 6 pages, 3 figure

General Scattering Mechanism and Transport in Graphene

Using quasi-time dependent semi-classical transport theory in RTA, we obtained coupled current equations in the presence of time varying field and based on general scattering mechanism $\tau \propto \mathcal{E}^{\beta}$. We find that close to the Dirac point, the characteristic exponent $\beta = +2$ corresponds to acoustic phonon scattering. $\beta = +1$ long-range Coulomb scattering mechanism. $\beta = -1$ is short-range delta potential scattering in which the conductivity is constant of temperature. The $\beta = 0$ case is ballistic limit. In the low energy dynamics of Dirac electrons in graphene, the effect of the time-dependent electric field is to alter just the electron charge by $e \to e(1 + (\Omega \tau)^2)$ making electronic conductivity non-linear. The effect of magnetic filed is also considered.Comment: 8 pages, 3 figure

External electric field effect on electron transport in carbon nanotubes

Electronic transport properties of carbon nanotubes are studied theoretically in the presence of external electric field E(t) by using the Boltzmann's transport with constant relaxation time. An analytical expression for the current densities of the nanotubes are obtained. It is observed that the current density-electric field characteristics of the CNs exhibit total self-induced transparency and absolute negative conductivityComment: 5 pages, 2 figure

Assessing Public Perception of Beach Quality for Ecotourism Development: A Case Study in Kokrobite Beach in the Greater Accra Region, Ghana

Tourism has become a major economic force in the world in recent times and seen as one of the fastest growing sectors of the 21st century. Over the years, tourism sector in Ghana has seen a drastic growth and ranked as the fourth foreign exchange earner for the country with a contribution of 6.2% to GDP in 2008 and 6.9% in 2011. However, tourism in Ghana still remains largely undeveloped and leaves much to be desired; with minimal support for tourism infrastructure. The objective of this paper is to assess the public preferences in selecting a beach and their perceptions of the quality of Kokrobite beach to recommend some management strategies and policies toward tourism development. A reconnaissance survey was conducted, followed by a survey of 150 beach users to collect relevant data. The study revealed that the preference for Kokrobite beach is influenced by specific characteristics such as less noise, security and landscape. Most of the tourists were satisfied with the availability of restaurants and bars, accommodation, noise level and access to the beach. They were, however, not satisfied with the level of sanitation and toilet facilities. It is recommended that the conservation of the natural environment, sanitation and an improvement in toilet facilities should be treated with utmost priority by managers of the beach to promote its patronage. Fencing of the beach was also recommended to prevent intrusion by humans as well as animals. Sea defense is also recommended to be built to check erosion, and lighting systems provided to promote the use of the beach at night. Key words: Environment, Greater Accra, landscape, Kokrobite beach, tourism and sanitation