Determinants of participation in rural non-farm economy in Zvimba District, Zimbabwe

The capacity of agriculture to provide sustainable livelihood opportunities is exceeded by the rural populations of developing countries, and with limited opportunities available in urban centres, the rural non-farm economy (RNFE) becomes pivotal in improving rural livelihoods. Within an empowerment agenda, it is important for policy makers to understand why households enter into the RNFE. We investigated participation in the RNFE of farm worker livelihoods along with the motivation for participation in RNF employment. Moreover, we sought to determine the key barriers and enablers to the adoption of high return strategies in RNFE activities by rural farm workers in Zimbabwe. Quantitative household surveys and qualitative focus group discussions were used to investigate levels of household dependency, education and skills, income accumulation and enterprising, expenditure and household assets. Our results showed that the primary motivation for entry into the RNFE was distress-pushed diversification. Our study found that market dynamics, limited skills, education level, and lack of capital are the paralysing factors towards significant income returns from RNFE for households. This information is critical for policy development for sustainable rural livelihoods, especially for rural farm workers who constitute the most vulnerable of the entire African rural population

Bond yield modelling and its application in the European Union

Forecasting crises has always been an interesting and important topic for econometricians or statisticians. Literature suggests that government bond yields can be a valid leading indicator for this purpose. This thesis uses government bond yields and applies various models to forecast the crisis which happened recently. Chapter 2 investigates a model utilising the term structure of interest rates to predict output growth and recession in the UK. In contrast to previous literature, information retrieved from the whole yield curve is used rather than just the yield spread. Using di�erent methods, our models are found to outperform the yield spread models both in in-sample and out-of-sample forecasting. Notably, the B-spline fitting model is able to forecast the 2009-2010 recession. Moreover, the model with lag of growth shows great forecasting ability in out-of-sample output growth forecasting. In most cases, models based on B-spline perform better than the ones based on the Diebold-Li framework. Chapter 3 examines the existence of time series non-linearities in the real output growth / recession-term spread relationship. Vector Autoregression (VAR), Threshold VAR (TVAR), Structural break VAR (SBVAR), Structural break threshold VAR (SBTVAR) are applied in the analysis. The in-sample results indicate there are non-linear components in this relationship. And this non-linearity tends to be caused by structural breaks. The best in-sample model also shows its robustness on arrival of new information in the out-of-sample tests. Evidence shows the model with only structural break non-linearity outperforms linear models in 1-quarter, 3-quarter and 4-quarter ahead forecasting. The European sovereign debt crisis has become a very popular topic since late 2009. In Chapter 4, the sovereign debt crisis is investigated by calculating the probabilities of the potential future crisis of 11 countries in the European Union. We use sovereign 2 3 spreads of the European countries against Germany as targets and apply the GARCH based vine copula simulation technique. The methodology solves the di�culties of calculating the probabilities of rarely happening events and takes sovereign debt movement dependence, especially tail dependence, into consideration. Results indicate that Italy and Spain are the most likely next victims of the sovereign debt crisis, followed by Ireland, France and Belgium. The UK, Sweden and Denmark, which are outside EMU, are the most financially stable countries in the sample

Un sistema di tipi per il linguaggio SPARQL

Il web semantico è nato dall’idea di favorire lo scambio di informazioni disponibili in rete non solo tra esseri umani ma anche tra applicazioni. A questo scopo sono stati sviluppati linguaggi in grado di esprimere tali informazioni in una forma comprensibile e processabile dalla macchina. Questi linguaggi formano quindi una struttura che permette la codifica, lo scambio e il riutilizzo di informazioni tra applicazioni distribuite, aziende e comunità. Uno di questi linguaggi è il Resource Description Framework (RDF), uno standard del W3C. È un linguaggio si asserzioni per descrivere in modo semplice le risorse (reperibili o no dal web), le proprietà e le relazioni tra esse. Il W3C ha anche standardizzato un linguaggio di interrogazione su grafi RDF chiamato SPARQL. Questa tesi si concentra sullo studio di questo linguaggio. Inizialmente propone una semantica formale per esso e in particolare definisce un sistema di tipi con l’obiettivo di descrivere il tipo del risultato della query e delle sue componenti. The semantic web arose from the idea to support exchange information between persons and applications. For this purpose are been developed many languages abled to express this informations in a understandable way by computer. These languages provides a structure that allows encoding, exchange and reuse information between distributed applications, companies and communities. One of these languages is Resourse Description Framework (RDF), a W3C standard. It’s a language of assertions, describe in a simple way resourses (from web or not), properties and relation about them. A W3C standard is also SPARQL, a query language of RDF graphs. This study is based on SPARQL. At the beginning proposes a formal semantics and in particular define a types system with the purpose of describe the type of query result and the type of query component

Spatio-temporal variation in the phytobenthos and phytoplankton community structure and composition of particulate matter along a river-estuary continuum assessed using microscopic and stable isotope analyses

Phytoplankton and phytobenthos communities play an important role in lotic systems as primary producers providing essential biomolecules to higher trophic oganisms and are important indicators for environmental or ecological change. In this thesis, field studies (observational and experimental) along a river–estuary continuum were conducted to assess the spatio-temporal variation and development of phytobenthos and phytoplankton communities using a combination of stable isotope and community analyses in a temperate southern African system across four study periods: September (early spring) and November/December (late spring) 2012, and February (summer) and May/June (winter) 2013. Additionally, the sources and composition of the particulate organic matter were also analysed using stable isotope (δ15N and δ13C) analysis. The effects of substrate type and flood occurrence were assessed through experimental studies at an up- and downstream site of the river after a major flood event that occurred between October and November 2012. Common household tiles were used as artificial substrates to study the development/succession of phytobenthos communities after the flood disturbance. Distinct diatom communities were observed between upstream and downstream sites and at each site, community structure changed with time indicating succession. In addition to recording diatom characteristics on three natural substrates, namely; macrophytes, rocks and sediment, artificial substrates observations were also made on three different types of artificial substrates, namely; brick, brown clay and grey clay tiles. The natural (species richness 78) and artificial substrates (sp. richness 93) had different communities with the latter having greater species richness. Common phytobenthos taxa were not restricted to a single substrate but preference was generally high for the artificial substrates, especially brown tiles (mean sp. richness 47). Results of the redundancy analysis (RDA) analysis indicated that ammonium, conductivity, total dissolved solids, salinity, pH, oxygen reduction potential, phosphate and water depth were the major determinants of the phytobenthos composition at the two sites. The spatio–temporal variation of phytoplankton and phytobenthos communities and allochthonous organic matter along the river–estuary continuum was assessed at 8 sites using a combination of community and stable isotope analyses. A total of 178 species belonging to 78 genera were recorded with diatoms being predominant, accounting for 81.9 % of the total abundance. The total chl-a concentration along the river-estuary continuum increased from spring to a high in summer before decreasing to a low in winter. Periphyton communities were observed to be significantly different across sites (p 50 %) in the upper to middle reaches (river), but low (< 20 %) in the lower reaches (estuary). The current investigation represents the first attempt to assess the validity of the River Continuum Concept (RCC) in a southern African temperate river. The phytoplankton and phytobenthos communities, and chl-a concentration followed a trend similar to that proposed for the river continuum concept (RCC). The middle reaches based on the phytobenthos or phytoplankton communities and chl-a concentrations which were employed as proxies for primary production, were the most productive, while the upper reaches were the least primary productive. The evaluation of organic matter contributions to the SPM and detritus along the river–estuary continuum provided a baseline assessment of the nature and sources of potential food for consumers inhabiting different locations during different times of the year. Incorporating such spatio-temporal variations in SPM and detritus into food web studies will improve our understanding of the flow of carbon through aquatic systems

Convective and stratiform rain: Multichannel microwave sensing over oceans

Measurements made by the Special Sensor Microwave/Imager (SSM/I) radiometer over the oceans, at 19, 37, and 85 GHz in dual polarization, are used to develop a model to classify rain into light-stratiform, moderately convective, and heavy convective types in the mesoscale convective systems (MCS). It is observed that the bulk of the 19- and 37-GHz data are linearly correlated with respect to one another, and generally increase together in brightness as the mean rain rate in the field of view (FOV) of the radiometer increases. However, a significant fraction of the data from these channels departs from this linear relationship, reflecting the nonuniform rain that is convective vs. the relatively light stratiform rain. It is inferred from the SSM/I data, in a MCS, when the slope dT sub 3/dT sub 19 is greater than unity there are optically thin clouds which produce light uniform rain. On the other hand, when dT sub 3/dT sub 19 is close to unity, the rain cells have an open structure and correspond to the convective type of rain. The openings between the cells are apparently a result of the downdrafts and/or entrainment. Relatively low values of 85-GHz brightness temperatures that are present when dT sub 37/dT sub 19 is close to unity support these views and, in addition, leads us to conclude that when the convection is heavy this brightness temperature decreases due to scattering by hydrometeors. On the basis of this explanation of the SSM/I data, an empirical rain retrieval algorithm is developed. Radar backscatter observations over the Atlantic Ocean next to Florida are used to demonstrate the applicability of this method. Three monthly mean maps of rainfall over the oceans from 50 degrees N to 50 degrees S, are presented to illustrate the ability of this method to sense seasonal and interannual variations of rain

Estimation of sea surface temperature from remote sensing in the 11-13 micron window region

The Nimbus 3 and 4 IRIS spectral data in the 11-13 micron water vapor window region are analyzed to determine the sea surface temperature (SST). The high spectral resolution data of IRIS are averaged over approximately 1 micron wide intervals to simulate channels of a radiometer to measure the SST. Three channels are utilized to measure SST over cloud-free oceans. However, two of these channels are sufficient in routine SST determination. The differential absorption properties of water vapor in the two channels enable one to determine the water vapor absorption correction without detailed knowledge of the vertical profiles of temperature and water vapor. The feasibility of determining the SST is demonstrated globally with Nimbus 3 data where cloud-free areas can be selected with the help of albedo data from the MRIR experiment on board the same satellite

Sea-land breeze as local wind, the numerical and analytical approach to its modeling, The

Includes bibliographical references.Lecture by Giovanni A. Dalu held at the International Center for Theoretical Physics-Trieste on 16-20 May 1988 during the workshop on Modeling of the Atmospheric Flow Field

Enhanced Self Interference Model Of Single Channel Full Duplex For Multi User-SIMO

Future telecommunications needs will increase, especially for multimedia based services and high speed data communications. Wide bandwidth and large capacity becomes very important. However, there are limitations on the available frequency spectrum, it necessary to have a new system that can give more efficient frequency spectrum. Full Duplex wireless communications system is a radio communication which transmit and receive signals can be carried out simultaneously at the same time and frequency. Toward the next generation of communication technology is experiencing a transition period. Where user equipment does not support the technology but BS have been using Full Duplex with multiple antennas in order to provide a good performance for uplink and the possibility to increase the capacity downlink in order to serve the needs of better capacity. In the previous research the Full Duplex MIMO system uses low frequencies for wireless point to point communications. For next generation technology we need higher frequencies. The 60 GHz frequency band is a good candidate for short and high speed data communications. The proposed system uses data transmission on Full Duplex system with multi user SIMO (MU-SIMO). In this research will make MU-SIMO Full Duplex communication model with K user single antenna that communicate towards uplink (Base Station) with multiple antenna. The effect of self-interference on the transceiver is simulated from 10% to 100% and takes into account the mutual coupling value of the antenna. Increasing the number of users on a full-duplex (FD) multiuser multiple-input multiple-output (MU-SIMO) technique increases the resulting BER, which means lower system performance. The higher the self-interference value due to signal leakage, the smaller BER will be obtained because of signal leakage is interfere the performance of the system, while the mutual coupling value on the antenna has little effect on the performance of the BER system because its value is relatively small close to zero. Therefore this calculation can be neglected because in designing antenna should have taken into account small value of mutual coupling. Multi user SIMO have better BER performance 13 times better than multi user SISO performance on Full Duplex Single Channel communication. Keyword : MU-SIMO, Self Interferenc, Mutual Coupling, Full Duplex Single Channe