Vegetative propagation studies of gum arabic trees : 2. The vegetative propagation of adult Acacia senegal

Le bouturage d'Acacia senegal est possible à partir de fragments de rameaux prélevés dans le houppier d'arbres adultes (13 ans). Le matériel végétal le plus réactif est constitué par des boutures de 15 cm de long (12 à 15 nouds) et de 10 +/- 6 mm de diamètre. L'ablation des feuilles avant mise en culture est un facteur favorable à l'enracinement des boutures. Celui-ci est aussi très influencé par la date de prélèvement des boutures et il varie de 10% en saison sèche à plus de 70% en saison des pluies. La collecte de boutures peut se faire sous forme de fragments de rameaux de 50 cm de long. Il est alors possible de conserver ce matériel pendant huit jours dans une toile maintenue humide et d'y découper les boutures au moment de la mise en place en pépinière. Les boutures présentent des caractères de maturité (croissance lente, plagiotropie, fructification). Il est cependant possible de conserver les génotypes ainsi mobilisés au champ, ou dans des pots en pépinière, afin d'amplifier le processus de rajeunissement physiologique en vue de leur clonage in vitr

Антисиметричнi хвилi в системi двох паралельних стержнiв, перiодично пiдкрiплених жорсткими поперечними перегородками i зв'язаних з акустичним середовищем

Розглянуто можливiсть поширення антисиметричних гармонiчних хвиль у системi двох перiодично пiдкрiплених жорсткими поперечними перегородками паралельних пружних стержнiв. При цьому вважалося, що обмеженi стержнями й сусiднiми перегородками об'єми заповненi акустичним середовищем (газом), а самi стержнi коливаються протифазно. Iз застосуванням методу Флоке одержано вiдповiдне дисперсiйне рiвняння i проаналiзовано його коренi. Збуджена таким способом хвиля - еквiволюмiальна, тому внутрiшнє акустичне середовище вiдiграє тут роль приєднаної маси. Як наслiдок, у цьому випадку ефективна пружнiсть системи i вiдповiдна швидкiсть поширення хвилi виявилися значно нижчими, нiж при синфазних коливаннях стержнiв, якi супроводжуються об'ємними деформацiями газонаповнених камер. Одержаний результат дозволяє на якiсному рiвнi пояснити деякi експериментальнi данi стосовно хвильових властивостей пористих газонаповнених середовищ, зокрема, легеневої паренхiми.Рассмотрена возможность распространения антисимметричных гармонических волн в системе двух периодически подкрепленных жесткими поперечными перегородками параллельных упругих стержней. При этом считалось, что ограниченные стержнями и соседними перегородками объемы заполнены акустической средой, а сами стержни колеблются противофазно. С применением метода Флоке получено соответствующее дисперсионное уравнение и проанализированы его корни. Возбужденная таким способом волна - эквиволюмиальная, поэтому внутренняя акустическая среда играет здесь роль присоединенной массы. Как следствие, в этом случае эффективная упругость системы и соответствующая скорость распространения волны оказались значительно ниже, чем при синфазных колебаниях стержней, которые сопровождаются объемными деформациями газонаполненных камер. Полученный результат позволяет на качественном уровне объяснить некоторые экспериментальные данные, касающиеся волновых свойств пористых газонаполненных сред, в частности, легочной паренхимы.The paper deals with considering the possibility of antisymmetric harmonic wave propagation in the system of two elastic rods periodically supported by rigid transverse barriers. The volumes bounded by the rods and adjacent barriers were considered to be filled with an acoustic medium (gas), with rods performing an antiphase motion. With use of the Floquet method, the corresponding dispersion equation has been obtained and its roots have been analyzed. The wave, excited in such way, is an equivoluminal one, therefore, the internal acoustic medium plays the role of an equivalent mass. Hence, in this case the effective system elasticity parameter and corresponding wave propagation velocity are considerably lower than that occurring at the in-phase rod vibration, accompanying by volume deformations of the gas-filled cells. The obtained result allows the qualitative explanation of some experimental data concerning wave properties of gas-filled porous media, in particular, the parenchyma of the lung

STABILITY AND EXTENT OF RESISTANCE OF COWPEA LINES TO FLOWER BUD THRIPS IN UGANDA

Cowpea ( Vigna unguiculata (L.) Walp.) is a legume attacked by several field insect pests, with flower thrips ( Megalurothrips sjostedti Trybom) being the most damaging. It causes 20 to 100% yield losses. Cowpea constitutes an important source of protein for resource poor households in Africa. The objective of this study was to identify cowpea lines that are resistant to flower thrips as a step in developing sustainable thrips management strategies. Seventy two cowpea cultivars were screened in three locations and two rainy seasons in Uganda, for thrips damage and yield components. Up to 11 cultivars (IT2841*Brown (1.50), MU20B (1.58), EBELAT*NE39 (1.61), WC17 (1.63), WC29 (1.65), MU24C (1.65), WC5 (1.66), NE46 (1.67), WC30 (1.68), NE67 (1.69), and NE51 (1.71)) were the most resistant and stable across locations. However, thrips damage was negatively correlated with the number of days to flowering (r = -0.32), indicating that the resistance in the cultivars was explained by the flower thrips infestation escape due to later flowering. Cultivar MU9 was high yielding (813.87 kg ha-1) and the most adapted genotype to all the locations; while cultivars WC26, NE48, and NE5 were the most adapted to Arua and Serere, and WC48A was the most adapted to Makerere University Agricultural Research Institute, Kabanyolo (MUARIK). There is potential of finding resistance sources in the cultivars tested.Le ni\ue9b\ue9 ( Vigna unguiculata (L.) Walp.) est une l\ue9gumineuse attaqu\ue9e par plusieurs insectes au champ avec thrips ( Megalurothrips sjostedti Trybom) le plus nuisible causant 20-100% de perte de rendement. Le ni\ue9b\ue9 constitue une source de prot\ue9ine bon-march\ue9 pour beaucoup de pauvres m\ue9nages en Afrique. L\u2019objectif de cette \ue9tude \ue9tait d\u2019identifier des vari\ue9t\ue9s plus r\ue9sistantes au thrips pour le d\ue9veloppement des strat\ue9gies de lutte durable. Soixante-douze vari\ue9t\ue9s du ni\ue9b\ue9 ont \ue9t\ue9 \ue9valu\ue9es dans trois environnements pendant deux saisons en Uganda pour les dommages, le rendement et ses composantes. Les donn\ue9es ont \ue9t\ue9 soumises aux analyses de variance et biplot de l\u2019effet de g\ue9notype et l\u2019interaction entre g\ue9notype et environnement (GGE). Les r\ue9sultats ont montr\ue9 un effet significatif (P<0.001) de l\u2019interaction entre g\ue9notype, environnement pour les scores de dommages caus\ue9s par thrips. Les vari\ue9t\ue9s les plus r\ue9sistantes et stables \ue9taient IT2841*Brown (1.50), MU20B (1.58), EBELAT*NE39 (1.61), WC17 (1.63), WC29 (1.65), MU24C (1.65), WC5 (1.66), NE46 (1.67), WC30 (1.68), NE67 (1.69), and NE51 (1.71). Toutefois, une corr\ue9lation n\ue9gative (r = -0.32) a \ue9t\ue9 observ\ue9e entre les scores de dommage et le nombre de jours de floraison indiquant que la r\ue9sistance observ\ue9e, \ue9tait due \ue0 un \ue9chappement par une floraison tardive. Le cultivar MU9 avait le rendement le plus \ue9lev\ue9 (813, 87 kg ha-1) et constituait le plus adapt\ue9 aux diff\ue9rents environnements alors que les cultivars WC26, NE48, and NE5 \ue9taient les plus adapt\ue9s \ue0 Arua et Serere, et WC48A \ue9tait le plus adapt\ue9 \ue0 l\u2019Institut de Recherches Agricoles de l\u2019Universit\ue9 de Makerere, Kabanyolo (MUARIK). Il y a potentiel de trouver de source de r\ue9sistance parmi les vari\ue9t\ue9s \ue9valu\ue9es

BIOCHEMICAL FACTORS ASSOCIATED WITH CASSAVA RESISTANCE TO WHITEFLY INFESTATION

Cassava ( Manihot esculenta Crantz) an important food security crop, is inflicted by whitefly ( Bemisia tabaci ) worldwide, causing direct damage of up to 80% of yield loss. Although resistance to the pest has been associated with antibiosis, changes that occur in metabolite activity, and their effect on the pest have not been fully elucidated. A study was carried out to evaluate changes in peroxidase, tannin and flavonoid activity in cassava genotypes attacked by B. tabaci in order to contribute to knowledge on whitefly resistance in cassava. Five genotypes showing resistance, and three susceptible, were selected based on whitefly count and leaf damage scores, and assayed for peroxidase, tannin and flavonoid activity. There were significant differences among genotypes for leaf damage (P < 0.01) of three to six months plants. Genotypes CS1-144, UG 120133 and NAM 130 showed low damage scores (< 2.00); but a high damage score (> 2.5) was incurred by UG 130068. All genotypes showed significant (P < 0.05) differences for peroxidase activity, with CS1-144 having a high activity rate three months after planting. The lowest activity was observed in UG 120170, a susceptible genotype. A significant (P < 0.01) negative correlation (r = -0.84) was observed between peroxidase activity and cassava leaf damage scores, as well as between tannin and damage (r = -0.57), indicating that peroxidase and tannin play a part in cassava resistance to B. tabaci.Le manioc ( Manihot esculenta Crantz) qui est une importante culture de s\ue9curit\ue9 alimentaire, est influenc\ue9e par la mouche blanche ( Bemisia tabaci ) sur le plan mondial, \ue0 travers des dommages directs allant jusqu\u2019\ue0 80% de perte du rendement. Par ailleurs, la r\ue9sistance \ue0 la peste a \ue9t\ue9 associ\ue9e \ue0 l\u2019antibiose, des changements qui apparaissent dans l\u2019activit\ue9 m\ue9tabolique, et leur effet sur la peste n\u2019ont pas encore \ue9t\ue9 compl\ue8tement \ue9lucid\ue9s. Une \ue9tude a \ue9t\ue9 entreprise pour \ue9valuer les changements d\u2019activit\ue9 en peroxydase, tannin et flavono\uefde dans les g\ue9notypes du manioc attaqu\ue9s par B. tabaci dans le but de contribuer au savoir sur la r\ue9sistance du\ua0manioc. Cinq g\ue9notypes, montrant r\ue9sistance, et trois susceptibles, \ue9taient s\ue9lectionn\ue9s sur la base du nombre de la mouche blanche et les sores de dommages et analys\ue9s pour l\u2019activit\ue9 en peroxydase, tannin and flavono\uefdes. Il y avait de diff\ue9rences significatives entre les g\ue9notypes pour les dommages caus\ue9s sur les feuilles (P< 0,01) des plantes de trois \ue0 six mois. Les g\ue9notypes CS1-144, UG 120133 et NAM 130 ont montr\ue9 de faibles scores de dommage (< 2,00); mais un score \ue9lev\ue9 de dommage (> 2,5) \ue9tait re\ue7u par UG 130068. Tous les g\ue9notypes ont montr\ue9 de diff\ue9rences significatives (P < 0,05) pour l\u2019activit\ue9 de peroxydase, avec CS1-144 ayant un taux d\u2019activit\ue9 \ue9lev\ue9 trois mois apr\ue8s la plantation. La faible activit\ue9 \ue9tait observ\ue9e sur UG 120170, un g\ue9notype susceptible. Une corr\ue9lation significative (P < 0,01) et n\ue9gative (r = -0,84) \ue9tait observ\ue9e entre l\u2019activit\ue9 de peroxydase et les scores de dommages sur les feuilles de manioc, ainsi que entre tannin et dommage (r = -0,57), indiquant que peroxydase et tannin jouent une part de r\uf4le dans la r\ue9sistance du manioc au B. tabaci

Caracterização fenológica de viníferas em região não tradicional do Agreste de Pernambuco.

O estudo teve como objetivo avaliar o desenvolvimento vegetativo, fenologia e exigência térmica de cultivares de videira para elaboração de vinhos finos introduzidas em microrregião de altitude no Nordeste

Caracterização fenológica de viníferas em região não tradicional do Agreste de Pernambuco.

O estudo teve como objetivo avaliar o desenvolvimento vegetativo, fenologia e exigência térmica de cultivares de videira para elaboração de vinhos finos introduzidas em microrregião de altitude no Nordeste.XV Congresso Latino-Americano de Viticultura e Enologia E XIII Congresso Brasileiro de Viticultura e Enologia. Bento Gonçalves-RS, 3 a 7 de Novembro de 2015

A double-blind placebo-controlled trial of azithromycin to reduce mortality and improve growth in high-risk young children with non-bloody diarrhoea in low resource settings: the Antibiotics for Children with Diarrhoea (ABCD) trial protocol

Background Acute diarrhoea is a common cause of illness and death among children in low- to middle-income settings. World Health Organization guidelines for the clinical management of acute watery diarrhoea in children focus on oral rehydration, supplemental zinc and feeding advice. Routine use of antibiotics is not recommended except when diarrhoea is bloody or cholera is suspected. Young children who are undernourished or have a dehydrating diarrhoea are more susceptible to death at 90 days after onset of diarrhoea. Given the mortality risk associated with diarrhoea in children with malnutrition or dehydrating diarrhoea, expanding the use of antibiotics for this subset of children could be an important intervention to reduce diarrhoea-associated mortality and morbidity. We designed the Antibiotics for Childhood Diarrhoea (ABCD) trial to test this intervention. Methods ABCD is a double-blind, randomised trial recruiting 11,500 children aged 2–23 months presenting with acute non-bloody diarrhoea who are dehydrated and/or undernourished (i.e. have a high risk for mortality). Enrolled children in Bangladesh, India, Kenya, Malawi, Mali, Pakistan and Tanzania are randomised (1:1) to oral azithromycin 10 mg/kg or placebo once daily for 3 days and followed-up for 180 days. Primary efficacy endpoints are all-cause mortality during the 180 days post-enrolment and change in linear growth 90 days post-enrolment. Discussion Expanding the treatment of acute watery diarrhoea in high-risk children to include an antibiotic may offer an opportunity to reduce deaths. These benefits may result from direct antimicrobial effects on pathogens or other incompletely understood mechanisms including improved nutrition, alterations in immune responsiveness or improved enteric function. The expansion of indications for antibiotic use raises concerns about the emergence of antimicrobial resistance both within treated children and the communities in which they live. ABCD will monitor antimicrobial resistance. The ABCD trial has important policy implications. If the trial shows significant benefits of azithromycin use, this may provide evidence to support reconsideration of antibiotic indications in the present World Health Organization diarrhoea management guidelines. Conversely, if there is no evidence of benefit, these results will support the current avoidance of antibiotics except in dysentery or cholera, thereby avoiding inappropriate use of antibiotics and reaffirming the current guidelines. Trial registration Clinicaltrials.gov, NCT03130114. Registered on April 26 2017

Impact of the introduction of pneumococcal conjugate vaccination on pneumonia in The Gambia: population-based surveillance and case-control studies.

BACKGROUND: Pneumococcal conjugate vaccines (PCVs) are used in many low-income countries but their impact on the incidence of pneumonia is unclear. The Gambia introduced PCV7 in August, 2009, and PCV13 in May, 2011. We aimed to measure the impact of the introduction of these vaccines on pneumonia incidence. METHODS: We did population-based surveillance and case-control studies. The primary endpoint was WHO-defined radiological pneumonia with pulmonary consolidation. Population-based surveillance was for suspected pneumonia in children aged 2-59 months (minimum age 3 months in the case-control study) between May 12, 2008, and Dec 31, 2015. Surveillance for the impact study was limited to the Basse Health and Demographic Surveillance System (BHDSS), whereas surveillance for the case-control study included both the BHDSS and Fuladu West Health and Demographic Surveillance System. Nurses screened all outpatients and inpatients at all health facilities in the surveillance area using standardised criteria for referral to clinicians in Basse and Bansang. These clinicians recorded clinical findings and applied standardised criteria to identify patients with suspected pneumonia. We compared the incidence of pneumonia during the baseline period (May 12, 2008, to May 11, 2010) and the PCV13 period (Jan 1, 2014, to Dec 31, 2015). We also investigated the effectiveness of PCV13 using case-control methods between Sept 12, 2011, and Sept 31, 2014. Controls were aged 90 days or older, and were eligible to have received at least one dose of PCV13; cases had the same eligibility criteria with the addition of having WHO-defined radiological pneumonia. FINDINGS: We investigated 18 833 children with clinical pneumonia and identified 2156 cases of radiological pneumonia. Among children aged 2-11 months, the incidence of radiological pneumonia fell from 21·0 cases per 1000 person-years in the baseline period to 16·2 cases per 1000 person-years (23% decline, 95% CI 7-36) in 2014-15. In the 12-23 month age group, radiological pneumonia decreased from 15·3 to 10·9 cases per 1000 person-years (29% decline, 12-42). In children aged 2-4 years, incidence fell from 5·2 to 4·1 cases per 1000 person-years (22% decline, 1-39). Incidence of all clinical pneumonia increased by 4% (-1 to 8), but hospitalised cases declined by 8% (3-13). Pneumococcal pneumonia declined from 2·9 to 1·2 cases per 1000 person-years (58% decline, 22-77) in children aged 2-11 months and from 2·6 to 0·7 cases per 1000 person-years (75% decline, 47-88) in children aged 12-23 months. Hypoxic pneumonia fell from 13·1 to 5·7 cases per 1000 person-years (57% decline, 42-67) in children aged 2-11 months and from 6·8 to 1·9 cases per 1000 person-years (72% decline, 58-82) in children aged 12-23 months. In the case-control study, the best estimate of the effectiveness of three doses of PCV13 against radiological pneumonia was an adjusted odds ratio of 0·57 (0·30-1·08) in children aged 3-11 months and vaccine effectiveness increased with greater numbers of doses (p=0·026). The analysis in children aged 12 months and older was underpowered because there were few unvaccinated cases and controls. INTERPRETATION: The introduction of PCV in The Gambia was associated with a moderate impact on the incidence of radiological pneumonia, a small reduction in cases of hospitalised pneumonia, and substantial reductions of pneumococcal and hypoxic pneumonia in young children. Low-income countries that introduce PCV13 with reasonable coverage can expect modest reductions in hospitalised cases of pneumonia and a marked impact on the incidence of severe childhood pneumonia. FUNDING: GAVI's Pneumococcal vaccines Accelerated Development and Introduction Plan, Bill & Melinda Gates Foundation, and UK Medical Research Council