582 research outputs found
Viral pneumonia in adults and older children in sub-Saharan Africa — epidemiology, aetiology, diagnosis and management
Community-acquired pneumonia causes substantial morbidity and mortality in sub-Saharan Africa with an estimated 131 million new cases each year. Viruses — such as influenza virus, respiratory syncytial virus and parainfluenza virus — are now recognised as important causes of respiratory disease in older children and adults in the developed world following the emergence of sensitive molecular diagnostic tests, recent severe viral epidemics, and the discovery of novel viruses. Few studies have comprehensively evaluated the viral aetiology of adult pneumonia in Africa, but it is likely to differ from Western settings due to varying seasonality and the high proportion of patients with immunosuppression and co-morbidities. Emerging data suggest a high prevalence of viral pathogens, as well as multiple viral and viral/bacterial infections in African adults with pneumonia. However, the interpretation of positive results from highly sensitive polymerase chain reaction tests can be challenging. Therapeutic and preventative options against viral respiratory infections are currently limited in the African setting. This review summarises the current state of the epidemiology, aetiology, diagnosis and management of viral pneumonia in sub-Saharan Africa
Use of Aluminum-Foil and Oat-Straw Mulches for Controlling Aster Leafhopper, \u3ci\u3eMacrosteles Fascifrons\u3c/i\u3e (Homoptera: Cicadellidae), and Aster Yellows in Carrots.
Aluminum-foil and oat-straw mulches significantly (P \u3c 0.05) reduced aster leafhopper numbers on carrots compared to an untreated control and a malathion spray treatment during the first half of the growing season. The amount of reflected light was significantly higher in both aluminum-foil and oat-straw mulched plots compared to unmulched treatments. Mulch effectiveness decreased when the closing carrot canopy reduced surface area of reflective mulches and amount of reflected light The percentage of aster yellows-infected plants was significantly lower (P \u3c 0.05) in aluminum-foil and straw mulches and in the malathion spray plots compared to the untreated control. Results demonstrated that aluminum-foil and straw mulches gave control of aster leafhoppers and aster yellows in carrots equal to that of a conventional insecticide spray program
Self-dual non-Abelian N = 1 tensor multiplet in D = 2+ 2 dimensions
We present a self-dual non-Abelian N=1 supersymmetric tensor multiplet in
D=2+2 space-time dimensions. Our system has three on-shell multiplets: (i) The
usual non-Abelian Yang-Mills multiplet (A_\mu{}^I, \lambda{}^I) (ii) A
non-Abelian tensor multiplet (B_{\mu\nu}{}^I, \chi^I, \varphi^I), and (iii) An
extra compensator vector multiplet (C_\mu{}^I, \rho^I). Here the index I is for
the adjoint representation of a non-Abelian gauge group. The duality symmetry
relations are G_{\mu\nu\rho}{}^I = - \epsilon_{\mu\nu\rho}{}^\sigma
\nabla_\sigma \varphi^I, F_{\mu\nu}{}^I = + (1/2)
\epsilon_{\mu\nu}{}^{\rho\sigma} F_{\rho\sigma}{}^I, and H_{\mu\nu}{}^I =
+(1/2) \epsilon_{\mu\nu}{\rho\sigma} H_{\rho\sigma}{}^I, where G and H are
respectively the field strengths of B and C. The usual problem with the
coupling of the non-Abelian tensor is avoided by non-trivial Chern-Simons terms
in the field strengths G_{\mu\nu\rho}{}^I and H_{\mu\nu}{}^I. For an
independent confirmation, we re-formulate the component results in superspace.
As applications of embedding integrable systems, we show how the {\cal N} = 2,
r = 3 and {\cal N} = 3, r = 4 flows of generalized Korteweg-de Vries equations
are embedded into our system.Comment: 21 pages, 0 figure
A contour matching approach for accurate NOAA-AVHRR image navigation
Although different methods for NOAA AVHRR image navigation have already been established, the multitemporal and multi-satellite character of most studies requires automatic and accurate methods for navigation of satellite images. In the proposed method, a simple Kepplerian orbital model for the NOAA satellites is considered as reference model, and mean orbital elements are given as input to the model from ephemeris data. In order to correct the errors caused by these simplifications, errors resulting from inaccuracies in the positioning of the satellite and failures in the satellite internal clock, an automatic global contour matching approach has been adopted. First, the sensed image is preprocessed to obtain a gradient energy map of the reliable areas (sea-land contours) using a cloud detection algorithm and a morphological gradient operator. An initial estimation of the reliable contour positions is automatically obtained. The final positions of the contours are obtained by means of an iterative local minimization procedure that allows a contour to converge on an area of high image energy (edge). Global transformation parameters are estimated based on the initial and final positions of all reliable contour points. Finally, the performance of this approach is assessed using NOAA 14 AVHRR images from different geographic areas.Postprint (published version
Anchoring symbols to sensorimotor control
This paper investigates how robots may emerge a lexicon to communicate complex meanings about actions such as `I am going to the red target' using simple (one-word) utterances. The main issue of the paper concerns the way these complex meanings represent the actions that are performed. It is argued that the meaning of these utterances may be represented without the need for categorising a complex flow of sensorimotor data. To illustrate the point, a simulation is presented in which robots develop such a communication system. The paper concludes by confirming that it is well possible to construct such a lexicon once robots have a number of basic sensorimotor skills available
Dutch Word Stress as Pronounced by Indonesian Students
This study focuses on the way in which the Dutch monophthongal vowels are pronounced by Indonesian students. To investigate whether Indonesian students realize the Dutch vowels correctly, especially when they are stressed, I analysed duration and quality of stressed and unstressed Dutch vowels. Measurements were done on the duration and the formant frequencies of the vowels spoken by Indonesian students and by native speakers of Dutch as well. Statistical analysis showed that in general the differences in duration between vowels spoken by the Indonesian students and by the native speakers were not significant. However, the effect of stress on the lengthening of the vowels was stronger for the Indonesian students than for the native speakers. In addition, statistical analysis of the formant frequencies confirmed that the non-native speakers realized the Dutch vowels slightly differently from the Dutch native speakers. The Indonesian students pronounced the stressed vowels more clearly than their unstressed counterparts; yet their vowel diagram is smaller than the vowel diagram of the native speakers
A Note on Equivalences in Measuring Returns to Scale in Multi-output-multi-input Technologies
In this article we show equivalence between the input oriented and output oriented scale elasticity measures for multi-output, multi-input technologies. We show the necessary and sufficient condition for this equivalence. We also provide a Lagrange multiplier (or shadow price) interpretation of the scale elasticity measure.
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