Nuchal Cord and Perinatal Outcome at the Yaounde General Hospital, Cameroon

The aim of this study was to determine the incidence of nuchal cord at delivery and perinatal outcome. We conducted a retrospective descriptive study from 1992–2008 at the Yaounde General Hospital. Obstetrical and neonatal variables were compared in the loose and tight nuchal cord groups and a control group (no nuchal cord). Of 9275 deliveries recorded, 16.2% had a nuchal cord. Of these nuchal cords, 75.81% were loose and 24.18% were tight. Cesarean delivery rate was lower in the loose and tight nuchal cord groups when compared with control group (P <.001;P < .05). Low Apgar scores < 7 at the 1st and 5th minutes were less in the loose nuchal cord group when compared with control group (P = .06, P = .7). In tight nuchal cord group, low Apgar score < 7 at the 1st minute was significantly higher, when low Apgar score < 7 at the 5th minute was non significantly higher when compared with control group (P < .001, P = .14). Transfer rate to neonatology unit was lower in the loose and tight nuchal cord than in the control group. Loose nuchal cord may not be associated with adverse perinatal outcome. However, tight nuchal cord may be associated with increased risk of low Apgar score < 7 at the 1st minute. Consequently, the ultrasound diagnosis of a nuchal cord at the end of pregnancy should not be the indication of elective cesarean delivery.Keywords nuchal cord; perinatal outcome; Apgar scor

Polaron in a quasi 1D cylindrical quantum wire

Polaron states in a quasi 1D cylindrical quantum wire with a parabolic confinement potential are investigated applying the Feynman variational principle. The effect of the wire radius on the polaron ground state energy level, the mass and the Frohlich electron-phonon-coupling constant are obtained for the case of a quasi 1D cylindrical quantum wire. The effect of anisotropy of the structure on the polaron ground state energy level and the mass are also investigated. It is observed that as the wire radius tends to zero, the polaron mass and energy diverge logarithmically. The polaron mass and energy differ from the canonical strong-coupling behavior by the Frohlich electron-phonon coupling constant and the radius of the quasi 1D cylindrical quantum wire that are expressed through a logarithmic function. Moreover, it is observed that the polaron energy and mass for strong coupling for the case of the quasi 1D cylindrical quantum wire are greater than those for bulk crystals. It is also observed that the anisotropy of the structure considerably affects both the polaron ground state energy level and the mass. It is found that as the radius of the cylindrical wire reduces, the regimes of the weak and intermediate coupling polaron shorten while the region of the strong coupling polaron broadens and extends into those of the weak and intermediate ones.За допомогою варіаційного принципу Фейнмана вивчаються стани полярона в квазіодновимірному циліндричному квантовому дроті з параболічним обмеженим потенціалом. Досліджується вплив радіуса дроту на енергетичний рівень основного стану полярона, масу і електрон-фонон постійну зв’язку Фрьоліха. Також вивчається ефект анізотропії структури на енергетичний рівень основного стану полярона і його масу. Виявлено, що якщо радіус дроту прямує до нуля, маса і енергія полярона розбігаються логарифмічно. Маса і енергія полярона відрізняються від канонічної поведінки сильного зв’язку на електрон-фонон постійну зв’язку Фрьоліха і на радіус квазіодновимірного циліндричного квантового дроту, які виражаються через логарифмічну функцію. Більше того, спостережено, що енергія та маса полярона для випадку квазіодновимірного циліндричного квантового дроту є більшими, ніж для випадку об’ємних кристалів. Також виявлено, що анізотропія структури сильно впливає на енергетичний рівень основного стану полярона та його масу. Знайдено, що якщо радіус циліндричного дроту зменшується, режими слабкого та середнього зв’язку полярона скорочуються, тоді як область сильного зв’язку полярона розширюється. Отримано аналітичні вирази для енергетичного рівня основного стану полярона і для його маси для випадку сильного зв’язку поляронів

Polaron in a quasi 1D cylindrical quantum wire

Polaron states in a quasi 1D cylindrical quantum wire with a parabolic con-finement potential are investigated applying the Feynman variational prin-ciple. The effect of the wire radius on the polaron ground state energy level, the mass and the Fröhlich electron-phonon-coupling constant are obtained for the case of a quasi 1D cylindrical quantum wire. The effect of anisotropy of the structure on the polaron ground state energy level and the mass are also investigated. It is observed that as the wire radius tends to zero, the polaron mass and energy diverge logarithmically. The polaron mass and energy differ from the canonical strong-coupling behavior by the Fröhlich electron-phonon cou-pling constant and the radius of the quasi 1D cylindrical quantum wire that are expressed through a logarithmic function. Moreover, it is observed that the polaron energy and mass for strong coupling for the case of the quasi 1D cylindrical quantum wire are greater than those for bulk crystals. It is also observed that the anisotropy of the structure considerably affects both the polaron ground state energy level and the mass. It is found that as the radius of the cylindrical wire reduces, the regimes of the weak and inter-mediate coupling polaron shorten while the region of the strong coupling polaron broadens and extends into those of the weak and intermediate ones. Analytic expressions for the polaron ground state energy level and mass are derived for the case of strong coupling polarons. Key words: polaron, polaron energy, polaron mass, parabolic confinement, Fröhlich electron-phonon coupling constant, quantum wir

Gestion participative du sanctuaire de gorilles de plaine de l'ouest (Gorilla gorilla gorilla) de Lossi en République du Congo- Brazzaville: première analyse de résultats et des contraintes

Participative Management of the Sanctuary of Western Lowland Gorillas (Gorilla gorilla gorilla) of Lossi in Republic of Congo-Brazzaville: Preliminary Results and Constraints Analysis. The gorilla sanctuary of Lossi experiments the synergy between scientific research and nature conservation. Three partners are involved in a management participative process. These partners include the Republic of Congo, the local community of Lossi and the European programme on the forest ecosystems in Central Africa. An investigation was carried out on the sanctuary of Lossi in 2003, in order to study in situ the effects generated by the participative management and to identify the constraints linked to the participative approach. The work of primatologists allowed the habituation of the gorillas to the human presence and opened eyesight tourism of western lowland gorillas. A camp for tourists and the access road to the sanctuary have been constructed. The tourism generated jobs in favour of the local population which is also a take-partner of contracts on road repairing. The income from the tourism allowed the construction of a health centre. However, the works of researchers and tourism activities failed during the outbreaks of the Ebola hemorrhagic fever and during the three civil war episodes. The consolidation and the long term of this process of co-management of natural resources of Lossi remains the establishment of a management that should include conservation, rural development and scientific research, with equitably in the distribution of gain between the partnerses

Les &#946-thalassemies de lfenfant camerounais : Etude de la symptomatologie en fonction des differentes formes biologiques

L'association ƒÀ-thalassemie et trait drepanocytaire donne lieu a des phenotypes varies. Elle peut engendrer des crises douloureuses vaso-occlusives. Nous avons observe dans notre pratique quotidienne des phenotypes S-ƒÀ-thalassemiques ou des sujets souffraient des crisesdouloureuses, tandis que dfautres en etaient indemnes. Notre objectif a ete de contribuer a une meilleure comprehension de lfexpression clinique de lfassociation des traits S et ƒÀ-thalassemique. Sur les 65 sujets inclus dans notre etude nous avions identifie neuf phenotypes de  ƒÀ-thalassemie, dont 29 (44,62%) HbSF, 20 (30,77%) HbA2SF, 2 (3,08%) HbA2S, 1 (1,54%) HbA1A2SF, 3 (4,62%) HbA1A2S et 2 (3,08%) HbA1SF, 1 (1,54%) HbA1A2, 6 (9,23%) HbA1A2F, 1 (1,54%) HbA2. Six de ces phenotypes regroupant 57 (87,69%) sujets etaient associes au trait drepanocytaire : les phenotypes HbSF, HbA2SF, HbA2S,HbA1A2SF ont ete constamment symptomatiques, tandis que la symptomatologie etait variable dfun sujet a lfautre au sein des phenotypes HbA1A2S et HbA1SF