Late-time growth rate, mixing and anisotropy in the multimode narrowband Richtmyer--Meshkov Instability: the θ\theta-Group Collaboration

Turbulent Richtmyer--Meshkov instability (RMI) is investigated through a series of high resolution three dimensional smulations of two initial conditions with eight independent codes. The simulations are initialised with a narrowband perturbation such that instability growth is due to non-linear coupling/backscatter from the energetic modes, thus generating the lowest expected growth rate from a pure RMI. By independently assessing the results from each algorithm, and computing ensemble averages of multiple algorithms, the results allow a quantification of key flow properties as well as the uncertainty due to differing numerical approaches. A new analytical model predicting the initial layer growth for a multimode narrowband perturbation is presented, along with two models for the linear and non-linear regime combined. Overall, the growth rate exponent is determined as $\theta=0.292 \pm 0.009$, in good agreement with prior studies; however, the exponent is decaying slowly in time. $\theta$ is shown to be relatively insensitive to the choice of mixing layer width measurement. The asymptotic integral molecular mixing measures $\Theta=0.792\pm 0.014$, $\Xi=0.800 \pm 0.014$ and $\Psi=0.782\pm 0.013$ which are lower than some experimental measurements but within the range of prior numerical studies. The flow field is shown to be persistently anisotropic for all algorithms, at the latest time having between 49\% and 66\% higher kinetic energy in the shock parallel direction compared to perpendicular and does not show any return to isotropy. The plane averaged volume fraction profiles at different time instants collapse reasonably well when scaled by the integral width, implying that the layer can be described by a single length scale and thus a single $\theta$. Quantitative data given for both ensemble averages and individual algorithms provide useful benchmark results for future research.Comment: 50 page

Make it on Her Own? The Portrayal of Single Women on Television from the 1970s to the 2010s

This longitudinal study examines the portrayal of single women on television series from the 1970s to the present demonstrating the changing perception of single women by American society through the history of television. The study first examines the demographic changes leading to the rise of singleness in three forms: never-married women divorced women and widowed women. The study then examines television as a cultural force which affects and reflects the way that Americans perceive themselves and others including single women. A qualitative and quantitative content analysis of six television series shows several trends which appeared throughout the series. In earlier series the episodes were focused on the workplace while in later shows more focused was placed on the personal life of the main character. The sexual relationships of main characters also increased chronologically. Television remains unrepresentative of the demographic of single women especially in regards to race and sexual orientation

Incorporating Wildlife Conservation within Local Land Use Planning and Zoning: Ability of Circuitscape to Model Conservation Corridors

Allocation of our world’s natural resources will become increasingly important as the human population continues to grow. Apportionment is especially imperative when considering the health of wildlife populations’ worldwide (Svoray, Bar, & Bannet, 2005; Theobald, Hobbs, Bearly, Zack, Shenk, & Riebsame, 2000). Efforts to provide basic infrastructure, housing, and food for a growing human population confounds the ability of wildlife to meet their own needs (Lagabrielle, Botta, Dare, David, Aubert, & Fabricius, 2010; Svoray et al., 2005). Previous research indicates that human conversion of native habitat is the leading threat to wildlife in the United States and throughout the world (Lagabrielle et al., 2010; Miller, Groom, Hess, Steelman, Stokes, Thompson, Bowman, Fricke, King, & Marquardt, 2009; Polasky, Nelson, Lonsdorf, Fackler, & Starfield, 2005; Stokes, Hanson, Oaks, Straub, & Ponio, 2009). Habitat conversion of the native landscape often results in the fragmentation of the landscape mosaic, severing the connection between habitat patches used by wildlife and populations of wildlife (Beir & Noss, 1998). Connectivity is crucial to wildlife for several reasons including dispersal, gene flow, and population persistence among other reasons (McRae, Dickson, Keitt, & Sirah, 2008). Conservation planning seldom occurs at local levels (i.e. municipal, county) rather it is often a product of national, state, or regional decision-making (Press, Doak, & Steinberg, 1996). The government levels at which the majority of wildlife management transpires is rarely the level at which habitat conversion takes place, the local level (Azzerad & Nilon, 2006). Increasingly scientists, ecologists, planners, and community members have been converging to incorporate wildlife and other ecological information into local land-use planning and decision-making (Theobald et al., 2000). Their ability to achieve this goal has evolved with the advancement of technology, specifically habitat models and geographic information system (GIS) (Roloff, Donovan, Linden, & Strong, 2009). This paper is a chapter within the context of a broader problem – loss of biodiversity worldwide, and its goal is to provide a summation of previous work centered on incorporating wildlife planning and subsequent ecological data within the framework of local land-use planning. In it, a review of current literature is summarized. In addition, ‘Circuitscape,’ a new and increasingly accepted corridor identification model is also examined. The primary objective of it is to provide techniques, tools, and processes by which planners and developers can attain wildlife conservation data in a format and scale deemed both meaningful and helpful

Identification des risques pluviométriques sur la culture du maïs dans l’arrondissement de Penka-Michel, dans les hautes terres de l’Ouest du Cameroun

Le maïs est la culture la plus développée à Penka-Michel, il se cultive aussi bien en hautes altitudes qu’en basses altitudes. Cette culture est cependant sensible aux aléas pluviométriques. L’objectif de l’étude est d’identifier les risques pluviométriques sur la culture du maïs. A partir des données météorologiques journalières de Penka-Michel, une analyse agroclimatique a été réalisée sur la période 1975-2011. A l’aide d’outils d’analyses statistiques, les occurrences des séquences sèches et pluvieuses ont été élaborées et la variabilité des précipitations en rapport avec la productivité du maïs établie. L’instabilité des dates de début et de fin des saisons des pluies a permis de prédire les périodes idéales des semis des cultures. D’une manière générale, les résultats obtenus montrent que le maïs pluvial de Penka Michel est confronté à deux risques pluviométriques majeurs, à savoir les déficits hydriques imputables à des séquences sèches et les excès pluviométriques liés aux phases excédentaires.Mots-clés: maïs pluvial, Penka-Michel, excès pluviométrique, déficit pluviométrique, dates instables de début et de fin des saisons des pluies. Identification of the rainfall risk on corn cultivation in the Penka-Michel Sub-division (in the highlands of western Cameroon) To Penka-Michel, the corn is the most significant culture in terms of surfaces and output. One finds it as well in high altitudes in low altitudes. However, the culture is sensitive to the pluviometric risks related to climatic variability. The aim of the study is to identify the pluviometric risks on the culture of corn. From the weather data day labourers of the pluviometric station of Penka-Michel, an agroclimatic analysis was carried out over the period 1975-2011. Using tools for statistical analyses, the variability of precipitations and key parameters of the agricultural season whose occurrences of dry and rainy sequences of great importance, the instability of the dates of beginning and end of the rains were analyzed in terms of risks of appearance. The results showed that the rain corn of the zone is confronted at the two major agro-pluviometric risks. It acts, on the one hand, of the ascribable hydrous deficits to dry sequences and on the other hand pluviometric excesses related to abundant rains. In addition, the number of days of rains necessary according to the average needs for corn for the two crop years in the medium constitutes another limit of the production. On the other hand, the pluviometric office plurality for any confused cycle does not seem to constitute of major agro-pluviometric risk for corn of the locality.Keywords: rain corn, Penka-Michel, pluviometric excess, pluviometric deficit, unstable dates of beginning and end of the rains

Genetic engineering of apple (Malus domestica Borkh.) for resistance to fungal diseases using g2ps1 gene from Gerbera hybrida (Asteraceae)

In the present study, g2ps1 gene from Gerbera hybrida coding for 2-pyrone synthase which contribute for fungal and insect resistance was used. The aim was to work out an efficient approach of genetic transformation for apple cvs. ‘Golden Delicious’, ‘Royal Gala’ and ‘MM111’, ‘M26’ rootstocks for improving their fungal resistance using genetic engineering techniques. Adventitious shoot formation from leaf pieces of apples studied was achieved using middle leaf segments taken from the youngest leaves from in vitro-grown plants.Optimum conditions for ‚direct’ shoot organogenesis resulted in high regeneration efficiency of  0%, 95%, 92%, 94% in the studied apples respectively. Putative transgenic shoots could be obtained on MS media with B5 Vitamins, 5.0 mg l-1 BAP, or 2.0 mg l-1 TDZ with 0.2 mg l-1 NAA in the presence of the selection agent “PPT” at 3.0-5.0 mgl-1. Shoot multiplication of transgenic shoots was achieved on: MS + B5 vitamins + 1.0 mg l-1 BAP + 0.3 mg l-1 IBA, 0.2 mg l-1 GA3+1.0 g/l MES+ 30 g/l sucrose + 7.0 g/l Agar, with the selection agent PPT at 5.0 mg l-1 and were subcultured every 4 weeks in order to get sufficient material to confirm transformation of the putative shoots obtained. Six, seven, one and six transgenic clones of the apples studied respectively have been obtained and confirmed by selection on the media containing the selection agent “PPT” and by PCR analysis using the suitable primers in all clones obtained for the presence of the selection” bar gene (447 bp) and the gene-of- interest “g2PS1” (1244 bp), with transformation efficiency of 0.4%, 0.6%, 0.1% and 0.3% respectively. These transgenic clones were multiplied further in vitro in the presence of the selection agent ‘PPT’ and rooted in vitro. Rooted transgenic plantlets were successfully acclimatized and are being kept under-containment conditions according to the biosafety by-law in Syria to evaluate their performance for fungal resistance

An implementation analysis of the Zibambele Road Maintenance Programme in the KwaZulu-Natal Department of Transport.

Thesis (M.Soc.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.The primary aim of the research study was to analyse the implementation of the Zibambele Road Maintenance Programme within the KwaZulu-Natal Department of Transport. The Zibambele Programme is one of South African government attempts to respond to social problems of poverty and unemployment. The Zibambele Programme identifies with the principles of Expanded Public Works Programme (EPWP). The research study identifies and discusses the obstacles to and challenges of the implementation of the Zibambele Road Maintenance Programme. Programme monitoring or process evaluation is used as an analytical framework of the study. The study employs Rossi and Freemans (1989) approach by examining the admission of the contractors into the programme, their progression and exit strategies. In order to best accomplish the objectives of the study and to provide an informed and critical analysis on the implementation of the Zibambele Programme, the study used both qualitative and quantitative research methodologies i.e. triangulation. For the quantitative method data was collected using in depth interview questions (i.e. face-to-face interviews) with the KwaZulu-Natal Department of Transport officials. The officials that were interviewed fall under the development directorate within the Department and they are directly responsible for the implementation of the Zibambele Programme. Four officials participated in the interviews and purposive sampling was used. For the quantitative method, the survey data collection method was employed to collect data from the Zibambele contractors. The contractors were randomly collected from the Pietermaritzburg and Empangeni regions. The results of the interviews were not generalised to all Zibambele contractors. However, the findings collected were useful as far as the implementation process of the Zibambele Programme is concerned. Content analysis was used to analyse qualitative data and descriptive statistics using the SPSS programme was used to analyse the quantitative data

The coupling of stimulated Raman and Brillouin scattering in a plasma

The observation of an anti-Stokes satellite in the spectrum of light backscattered from a CO2 laser plasma is reported. Its origin is found to be Thomson scattering of the incident light from a counterpropagating mode-coupled plasma wave. The parent electron and ion waves in the mode-coupling process were driven by stimulated Raman and Brillouin backscattering. The parent and daughter plasma waves were detected by ruby laser Thomson scattering. A computer simulation modeling the experiment shows further cascading of the Stokes backscattered light to lower frequencies, apparently a result of its rescattering from another, higher phase velocity, counterpropagating coupled mode. Comparisons with theoretical predictions are presented

Analyse des précipitations annuelles à la station de Yaoundé de 1895 à 2006

Dans le cadre des changements climatiques nous nous proposons pour la station météorologique de Yaoundé, située dans la région du climat équatorial classique, d’étudier le comportement des pluies interannuelles. A ce jour, cette station est confrontée à diverses perturbations pluviométriques : Sur le plan de la pluviométrie mensuelle, les mois de décembre, de janvier et de février certes appartenant à la grande saison sèche n’enregistrent parfois aucune pluie. Or cette situation n’est pas normale entre 1926 et 2006 avec des moyennes de 21,4 mm pour le mois de janvier, 51 mm pour le mois de février et 135.7 mm pour le mois de mars. Certains de ces mois enregistrent des précipitations largement supérieures à la normale. C’est le cas de janvier 1975 avec 98 mm ; de février 1969 avec 125,9 mm et de décembre 1964 avec 97,5 mm. Sur le plan saisonnier, les répits pluviométriques des grandes saisons sèches s’érigent dans la plupart des cas à de véritables sécheresses. C’est le cas de 1987 qui a enregistré que 24,6 mm de précipitations durant les mois de décembre, janvier et février au lieu de 94,1mm en moyenne au total. Dans le même ordre, nous notons une modification dans la distribution des précipitations saisonnières. En outre, la petite saison sèche semble enregistrer de plus en plus des précipitations que jadis. Quant aux précipitations interannuelles, il ressort qu’il y a non seulement une diminution, mais aussi un prolongement des années sèches et, un déphasage entre l’arrivée des premières et la fin des dernières pluies.Mots-clés: Yaoundé, précipitations, saisons, sécheresse, El Niño. Analysis of the annual rainfalls in the Yaounde station from 1895 to 2006In the context of climate change, we propose for the Yaounde weather station, in the area of the classic equatorial climate, to study the behavior of interannual rainfalls. It follows a variety rainfall interference. In terms of monthly rainfall, the months of December, January and February certainly belonging to the long dry season, sometimes recorded no rain. But this situation is not normal between 1926 and 2006 with averages of 21.4 mm for the month of January, 51 mm for the month of February and 135.7 mm for the month of March. Some of these months are above normal precipitations. This is the case of January 1975 with 98 mm; February 1969 with 125.9 mm and December 1964 with 97.5 mm. At the seasonal level, rainfall respites large dry seasons are erected in most cases to real drought. This was the case from 1987 which recorded 24.6 mm rainfall during the months of December, January and February instead of average total 94,1mm. Similarly, we note a change in the distribution of seasonal rainfall. In addition, the short dry season record seems more rainfall than before. As for interannual rainfall, it is apparent that there has not only reduced but also an extension between the arrival of the first and the end of the last rains.Keywords: Yaounde, rainfalls, seasons, drought, El Niño

A comparative study of the influence of climatic elements on cocoa production in two agrosystems of bimodal rainfall: Case of Ngomedzap forest zone and the contact area of forest-savanna of Bokito

Cocoa production in Cameroon, cultivated on a surface area estimated at 450,000 hectares stood at 200.000 tons in 2012 and represented 2.1% of GNP. This productivity remains low compared to that of other African countries like Ivory Coast, Ghana and Nigeria. This paper aims at determining and comparing the influence of climate on cocoa production in the forest zone of Ngomedzap and the Bokito savanna zone. Ngomedzap has an equatorial Guinean climate type with bimodal rainfall characterized by the alternation of two dry seasons and two rainy seasons of varying durations. The average annual temperature in Ngomedzap is 25.5°C and the average annual rainfall is between 1500mm and 1700 mm . The climate in Bokito is equatorial transition type with a bimodal rainfall, characterized by two rainy seasons and two dry seasons with variable durations. The average temperature is 26.8°C and the average annual rainfall is between 1200mm and 1450 mm. Generally, despite the precarious climate, the influence of climatic parameters on the production of cocoa is more significant in Bokito than in Ngomedzap. The Bokito zone with less precipitation is more favourable for flowering than in Ngomedzap, with 4% and 2.2% respectively while the formation of pods is equally 32.4% in Bokito compared to barely 2.8 % in Ngomedzap. The notion that cocoa production is exclusive to the forest area is accordingly not the rule anymore. These results are useful in situating suitable areas of cocoa production in Cameroon.Keywords: Climate, cocoa, production, rainfall, Cameroon, agrosystemJOURNAL OF THE CAMEROON ACADEMY OF SCIENCES VOL. 11 No. 1 (2013