The Comparative Effects of Simulation Games and Brainstorming Instructional Strategies on Junior Secondary School Students’ Achievement in Social Studies in Nigeria

The study investigated the comparative effects of simulation games andbrainstorming instructional strategies on Junior Secondary School Students’achievement in Social Studies in Nigeria. The study adopted a quasiexperimental design (3 x 2 non-randomized pre-test, post-test control group) comprising three groups made up of two experimental groups and one control. Simple random sampling was employed in selecting 240 students from six selected schools comprising two arms of JSS 2. Four instruments namely: “Social Studies Achievement Test” (SSAT), “Operational Guide for Simulation Games” (OGSG), “Operational Guide on Brainstorming” (OGB) and “Operational Guide for Teacher Exposition” (OGTE) were used with reliability coefficients of 0.84, 0.76, 0.81 and 0.78 respectively. Three research hypotheses were generated and tested. Data analysis was done using mean, standard deviation, and Analysis of Covariance (ANCOVA). Results revealed that there was a significant main effect of the treatment on students’ achievement in Social Studies (F(2,233) = 159.321; P < 0.05). Findings also indicated that there was a significant main effect of gender on students’ achievement in Social Studies. (F(1.233) = 20.687; P < 0.05) and finally, results showed that there was significant interaction effect of treatment and gender on students’ achievement in Social Studies (F(2.233) = 17.644; P < 0.05). Based on the findings of the study, recommendations were made.Key words: Simulation games, brainstorming, instructional strategies,students’ achievement, Social Studie

Criblage phytochimique et potentiel érectile de Turraea heterophylla de Côte d’Ivoire

Objectif : l’étude a pour objet de rechercher de nouvelles sources végétales médicamenteuses dans le traitement de l’impuissance sexuelle.Méthodologie et résultats: Ainsi, le criblage phytochimique réalisé sur l’extrait de Turraea heterophylla (Eth) communément appelé "cure-dent gouro", a révélé la présence de phytocomposés tels que les stérols, terpènes, alcaloïdes, coumarines, sucres réducteurs, polyphénols, saponines stéroïdes et les protéines. L’évaluation de l’effet de Eth sur l’artère aorte isolé de cobaye a montré une vasorelaxation favorable à une meilleure circulation sanguine, laquelle est à l’origine du potentiel érectile. Ce potentiel érectile serait lié à l’action de certains métabolites secondaires tels que les terpènes et les alcaloïdes détectés dans Eth. Par ailleurs, Eth induit des effets secondaires négligeables sur la pression artérielle (hypotension dosedépendante) et sur l’électrocardiogramme (inhibition modérée de l’activité cardiaque).Conclusion et application : Le criblage phytochimique réalisé sur l’extrait méthanolique de Turraea heterophylla (Eth) a permis d’identifier des stérols, terpènes, alcaloïdes, coumarines, sucres réducteurs, polyphénols, saponosides stéroïdes et des protéines. A cette plante couramment employée par les guérisseurs pour traiter les troubles érectiles en Côte d’Ivoire, nous avons rattaché la vasorelaxation à l’érection pénienne. Eth induit une vasorelaxation favorable à une meilleure circulation sanguine, laquelle est à la base du potentiel érectile qui serait lié à l’action de certains métabolites secondaires suspectés tels que les terpènes et les alcaloïdes décelés dans Eth. Par ailleurs, Eth induit une hypotension dosedépendante et une inhibition modérées de l’activité cardiaque. Ces tests biologiques indiquent bien que Turraea heterophylla a non seulement des propriétés érectiles mais également manifeste des effets secondaires négligeables sur la pression artérielle et sur l’électrocardiogramme. C’est donc une approche rationnelle qui justifierait l’emploi récurrent de cette plante dans le traitement traditionnel de l’impuissance sexuelle en Côte d’Ivoire.Mots clés: Turraea heterophylla, criblage phytochimique, potentiel érectile, Côte d’Ivoir

Comparative biochemical and molecular evaluation of swarming of Proteus and effects of anti-swarm agents

In addition to inadequate understanding of swarming motility and virulence of Proteus, there is paucity of information on the relative effectiveness of the various anti-swarm agents. The anti-swarming effects of urea, sodium dodecylsulphate (SDS) and trihydroxymethylglycine (Tris) on 40 clinical isolates of Proteus Spp. were comparatively investigated and plasmids associated with swarming were characterized. The three substances elicited a comparable concentration-dependent anti-swarming property at 0.25 – 1.25% on nutrient agar. Anti-swarm agents displayed heterogeneity in their ability to cause significant decreases in the expression of virulence factors. Swarm motility was further found to be strongly associated with the expression of virulence factors in these strains. Of the Proteus strains tested, 32 were found to harbour 1 – 4 plasmids of size ranging from 6.0 – 33.5 kb. Plasmid curing resulted in loss of swarming in 65.6% of these strains. In order to reduce the risk of infection with virulent Proteus strains, the laboratory use of urea and SDS is suggested. Key Words: Proteus, swarming, urea, SDS, Tris. African Journal of Biotechnology Vol.3(1) 2004: 99-10

Lymphomas of the female genital tract in Ibadan

Context: Female genital tract cancers are second only to breast malignancies. Cervical cancer is the commonest while epithelial cancers constitute the major histologic type. Lymphoid neoplasms are extremely rare, with the Burkitt's variety accounting for majority of cases seen in the African female.Objective: This is a review of the obstetric/gynaecological patients seen at the University College Hospital, Ibadan between 1976 and 2005, predating the commencement of a nationwide research into non – Hodgkin's lymphoma funded by the Aboderin Foundation.Study Design: Records of subjects were analysed for their  sociodemographic and clinicopathological characteristics, recruiting only those who satisfy the criteria for diagnosing genital tract lymphomas according to Kosari et al1. Retrievable archival paraffin blocks of subjects were also analysed using immunophenotyping.Results: Fifteen cases were identified within the study period; the highest yearly incidence rate being 3 in 1977. In eighteen of the years studied no cases were seen. Most cases (80.0%) occurred in the ovaries. Eighty percent (12) of patients were 25 years or below and nulliparas and grandmultiparas formed 46.7 and 13.4% respectively. Unilateral orbilateral oophorectomy was the commonest surgical procedure (53.3%) while 20.0% had total abdominal hysterectomy with or without bilateral salpingoophorectomy. Data were unavailable concerning use of adjuvanttherapy and outcome of treatment. Four archival paraffin blocks were available for immunophenotyping using the affordable panel of CD20, CD10 and Bcl – 2 antibodies; all were Burkitt's lymphoma.Conclusion: Female genital lymphomas are very rare, affecting the young and nulliparous. The Burkitt's type is commonest

Free Wave Propagation in Plates of General Anisotropic Media

The propagation of Lamb waves in plates has been the subject of numerous investigations since their postulation by Lamb in 1916 [1,2]. Most of the work in existence deals with various aspects of these guided waves in plates of isotropic materials. Comparatively speaking a limited number of results has appeared in which Lamb or horizontaly polarized SH wave propagation in anisotropic plates has been considered in any detail. For Lamb waves, theoretical analyses have been reported in plates of cubic [3,4], transversely isotropic [5,6], and orthotropic [7,9] media

Neutron Scattering and Its Application to Strongly Correlated Systems

Neutron scattering is a powerful probe of strongly correlated systems. It can directly detect common phenomena such as magnetic order, and can be used to determine the coupling between magnetic moments through measurements of the spin-wave dispersions. In the absence of magnetic order, one can detect diffuse scattering and dynamic correlations. Neutrons are also sensitive to the arrangement of atoms in a solid (crystal structure) and lattice dynamics (phonons). In this chapter, we provide an introduction to neutrons and neutron sources. The neutron scattering cross section is described and formulas are given for nuclear diffraction, phonon scattering, magnetic diffraction, and magnon scattering. As an experimental example, we describe measurements of antiferromagnetic order, spin dynamics, and their evolution in the La(2-x)Ba(x)CuO(4) family of high-temperature superconductors.Comment: 31 pages, chapter for "Strongly Correlated Systems: Experimental Techniques", edited by A. Avella and F. Mancin

Terminal Pleistocene Alaskan genome reveals first founding population of Native Americans

Despite broad agreement that the Americas were initially populated via Beringia, the land bridge that connected far northeast Asia with northwestern North America during the Pleistocene epoch, when and how the peopling of the Americas occurred remains unresolved. Analyses of human remains from Late Pleistocene Alaska are important to resolving the timing and dispersal of these populations. The remains of two infants were recovered at Upward Sun River (USR), and have been dated to around 11.5 thousand years ago (ka). Here, by sequencing the USR1 genome to an average coverage of approximately 17 times, we show that USR1 is most closely related to Native Americans, but falls basal to all previously sequenced contemporary and ancient Native Americans. As such, USR1 represents a distinct Ancient Beringian population. Using demographic modelling, we infer that the Ancient Beringian population and ancestors of other Native Americans descended from a single founding population that initially split from East Asians around 36 ± 1.5 ka, with gene flow persisting until around 25 ± 1.1 ka. Gene flow from ancient north Eurasians into all Native Americans took place 25–20 ka, with Ancient Beringians branching off around 22–18.1 ka. Our findings support a long-term genetic structure in ancestral Native Americans, consistent with the Beringian ‘standstill model’. We show that the basal northern and southern Native American branches, to which all other Native Americans belong, diverged around 17.5–14.6 ka, and that this probably occurred south of the North American ice sheets. We also show that after 11.5 ka, some of the northern Native American populations received gene flow from a Siberian population most closely related to Koryaks, but not Palaeo-Eskimos, Inuits or Kets, and that Native American gene flow into Inuits was through northern and not southern Native American groups. Our findings further suggest that the far-northern North American presence of northern Native Americans is from a back migration that replaced or absorbed the initial founding population of Ancient Beringians

Femtosecond control of electric currents at the interfaces of metallic ferromagnetic heterostructures

The idea to utilize not only the charge but also the spin of electrons in the operation of electronic devices has led to the development of spintronics, causing a revolution in how information is stored and processed. A novel advancement would be to develop ultrafast spintronics using femtosecond laser pulses. Employing terahertz (10$^{12}$ Hz) emission spectroscopy, we demonstrate optical generation of spin-polarized electric currents at the interfaces of metallic ferromagnetic heterostructures at the femtosecond timescale. The direction of the photocurrent is controlled by the helicity of the circularly polarized light. These results open up new opportunities for realizing spintronics in the unprecedented terahertz regime and provide new insights in all-optical control of magnetism.Comment: 3 figures and 2 tables in the main tex

Photonic Analogue of Two-dimensional Topological Insulators and Helical One-Way Edge Transport in Bi-Anisotropic Metamaterials

Recent progress in understanding the topological properties of condensed matter has led to the discovery of time-reversal invariant topological insulators. Because of limitations imposed by nature, topologically non-trivial electronic order seems to be uncommon except in small-band-gap semiconductors with strong spin-orbit interactions. In this Article we show that artificial electromagnetic structures, known as metamaterials, provide an attractive platform for designing photonic analogues of topological insulators. We demonstrate that a judicious choice of the metamaterial parameters can create photonic phases that support a pair of helical edge states, and that these edge states enable one-way photonic transport that is robust against disorder.Comment: 13 pages, 3 figure

Declining Burden of Malaria Over two Decades in a Rural Community of Muheza District, North-Eastern Tanzania.

The recently reported declining burden of malaria in some African countries has been attributed to scaling-up of different interventions although in some areas, these changes started before implementation of major interventions. This study assessed the long-term trends of malaria burden for 20 years (1992--2012) in Magoda and for 15 years in Mpapayu village of Muheza district, north-eastern Tanzania, in relation to different interventions as well as changing national malaria control policies.\ud Repeated cross-sectional surveys recruited individuals aged 0 -- 19 years from the two villages whereby blood smears were collected for detection of malaria parasites by microscopy. Prevalence of Plasmodium falciparum infections and other indices of malaria burden (prevalence of anaemia, splenomegaly and gametocytes) were compared across the years and between the study villages. Major interventions deployed including mobile clinic, bed nets and other research activities, and changes in national malaria control policies were also marked. In Magoda, the prevalence of P. falciparum infections initially decreased between 1992 and 1996 (from 83.5 to 62.0%), stabilized between 1996 and 1997, and further declined to 34.4% in 2004. A temporary increase between 2004 and 2008 was followed by a progressive decline to 7.2% in 2012, which is more than 10-fold decrease since 1992. In Mpapayu (from 1998), the highest prevalence was 81.5% in 1999 and it decreased to 25% in 2004. After a slight increase in 2008, a steady decline followed, reaching <5% from 2011 onwards. Bed net usage was high in both villages from 1999 to 2004 (>=88%) but it decreased between 2008 and 2012 (range, 28% - 68%). After adjusting for the effects of bed nets, age, fever and year of study, the risk of P. falciparum infections decreased significantly by >=97% in both villages between 1999 and 2012 (p < 0.001). The prevalence of splenomegaly (>40% to <1%) and gametocytes (23% to <1%) also decreased in both villages.Discussion and conclusionsA remarkable decline in the burden of malaria occurred between 1992 and 2012 and the initial decline (1992 -- 2004) was most likely due to deployment of interventions, such as bed nets, and better services through research activities. Apart from changes of drug policies, the steady decline observed from 2008 occurred when bed net coverage was low suggesting that other factors contributed to the most recent pattern. These results suggest that continued monitoring is required to determine causes of the changing malaria epidemiology and also to monitor the progress towards maintaining low malaria transmission and reaching related millennium development goals