The Effectiveness of School Heads Towards Enhancing Students’ Academic Performance in Secondary Schools in Urban District - Unguja.

Poor student’s academic performance is a serious problem facing public secondary schools both in the Mainland Tanzania and Zanzibar. This study the effectiveness of school heads towards enhancing student’s academic performance in Urban District in Unguja-Zanzibar has been assessed using five secondary schools. Target population comprised of five school heads and eighty-five informants, namely one District Education Officer, five head prefects, twenty-five teachers, forty-five students and nine school committee members. The study used descriptive survey design with questionnaires and interviews as data collection instruments. School heads in poorly performing schools were found with skill deficiencies in carrying some management and leadership duties for effective enhancement of student’s academic performance such as (i) development of appealing school visions and their effective communication to stakeholders to rally support and assistance, (ii) effective supervision/monitoring of teaching and learning processes, and (iii) development of motivation systems for promoting teaching and learning processes. School heads of better performing schools (a) had more regular tendency of supervising teachers’ and students’ academic works, (b) were clearer in motivation system used to promote teaching and learning, (c) attended their classes more regularly than those in low performing schools. In view of the findings, it was concluded that the more the school heads were equipped with skills relevant for promoting effective teaching and learning, the greater were the impacts of such school heads. It is recommended that school heads recruitment processes should consider assessing management and leadership skills and in-service training sessions to update such skills. Key words: Academic, Effectiveness, Performance, Secondary School

Charge Localization and Ordering in A2_2Mn8_8O16_{16} Hollandite Group Oxides: Impact of Density Functional Theory Approaches

The phases of A$_2$Mn$_8$O$_{16}$ hollandite group oxides emerge from the competition between ionic interactions, Jahn-Teller effects, charge ordering, and magnetic interactions. Their balanced treatment with feasible computational approaches can be challenging for commonly used approximations in Density Functional Theory. Three examples (A = Ag, Li and K) are studied with a sequence of different approximate exchange-correlation functionals. Starting from a generalized gradient approximation (GGA), an extension to include van der Waals interactions and a recently proposed meta-GGA are considered. Then local Coulomb interactions for the Mn $3d$ electrons are more explicitly considered with the DFT+$U$ approach. Finally selected results from a hybrid functional approach provide a reference. Results for the binding energy of the A species in the parent oxide highlight the role of van der Waals interactions. Relatively accurate results for insertion energies can be achieved with a low $U$ and a high $U$ approach. In the low $U$ case, the materials are described as band metals with a high symmetry, tetragonal crystal structure. In the high $U$ case, the electrons donated by A result in formation of local Mn$^{3+}$ centers and corresponding Jahn-Teller distortions characterized by a local order parameter. The resulting degree of monoclinic distortion depends on charge ordering and magnetic interactions in the phase formed. The reference hybrid functional results show charge localization and ordering. Comparison to low temperature experiments of related compounds suggests that charge localization is the physically correct result for the hollandite group oxides studied here. . . .Comment: 16 pages, 8 figure

The Need of a Structured Tilapia Breeding Program in Tanzania to Enhance Aquaculture Production: A Review

Breeding programs are crucial for boosting productivity and increase sustainability of aquaculture. Over years, Tanzania has witnessed fluctuation in its capture fisheries production from 320,900 to 375, 535 and back to 362,595 metric tonnes in the years 2000, 2005 and 2016, respectively (URT 2016). The declining trend in fish production has made fish supply in the country unstable and conversely, increased the demand for fishes to about 730,000 metric tonnes in 2017. However, the local aquaculture production has not increased accordingly. Tanzania is importing fish mainly from Asia to meet its increased demand. In 2017, a total of 2,055,721 kg of frozen tilapia were imported from China and Mozambique (URT 2017). The introduction of exotic fish species in Tanzania should be carefully managed because introduced species have many negative impacts to the indigenous species. Tanzania should have a moderate scale tilapia breeding program that will produce good quality fingerlings at affordable price for smallholder fish farmers. The availability of reliable good quality fingerlings is key to improve aquaculture production in the country. Among 17 existing hatcheries, only 12 hatcheries are active, however these hatcheries are not performing well due to low investment and technology leading to the production of low quantity and quality fingerlings. The need for a structured sustainable Tilapia breeding program with bio secured and reliable hatcheries to enhance aquaculture production in Tanzania is given in this review.Keywords: Aquaculture, Breeding programs, Nile tilapia, Local strains

Replacing expensive synthetic media with banana stem compost extract medium for production of Chlorella vulgaris

ABSTRACTMicroalgal cultivation by small scale aquaculture farmers is limited by the high cost of synthetic culture media. The current study was conducted to investigate use of banana stem compost extract (BSCE) as an alternative medium for cultivation of the microalga Chlorella vulgaris. C. vulgaris was batch cultured for 24 days in the laboratory using synthetic Bold Basal Medium (BBM) as a control and BSCE at concentrations of 2%, 5% and 10% (by volume) as the treatments. Algal growth was evaluated by measuring dry cell weight and specific growth rate (SGR) during the experimental period. Chemical composition was analysed following standard analytical methods. Variations in growth trends among culture media were attributed to variations in nutrient concentration and lack of acclimatization period. Some macro- and micronutrients in BSCE-cultivated C. vulgaris were higher than or similar to those observed in BBM-cultivated algae. The macronutrients differed among BSCE treatments. It was concluded that BSCE can be used as the culture medium, providing similar nutritional value and supporting similar growth performance to synthetic media. However, selection of BSCE concentration should be based on macronutrients and take into account the intended use of cultivated microalgae

Growth performance of five different strains of Nile tilapia (Oreochromis niloticus) introduced to Tanzania reared in fresh and brackish waters

Five introduced strains of Nile tilapia (Oreochromis niloticus) were tested for growth performance both in fresh- and brackish-water (2 salinity units) environments for 56 days. The BIG NIN, GIFT, Chitralada, "Ruvu Farm" and Silver YY strains with initial mean average weight (+/- standard error) of 96.4 +/- 6.90 g, 104.1 +/- 7.19 g, 137.2 +/- 7.21 g, 53.2 +/- 6.98 g and 95.3 +/- 7.11 g, respectively were used. Individuals were tagged and pooled in hapas (12 mx8.5 mx2 m each), aligned into different ponds (20 mx20 m each). Stocking density of 5 fish/m(2) and 350 g/kg crude protein diet were used. Overall, the average weight gain for GIFT strain was 7.5%, 32%, 45% and 86.5% higher than BIG NIN, Chitralada, "Ruvu Farm" and Silver YY strains, respectively, across both environments. All strains performed significantly better (p<0.05) when reared in brackish-water than their respective counterparts in freshwater, except for the BIG NIN strain. The morphometric correlations for all strains in both environments ranged from moderate (0.50) to strong positive (0.92). The GIFT strain demonstrated superior growth and genotype by environment interaction was weak and not important to be prioritized in breeding programs

Spirulina (Arthrospira fusiformis) as a potential protein source in practical diets for fry mariculture of Rufiji tilapia (Oreochromis urolepis urolepis)

The effects on growth performance, feed utilization, survival and whole fish body proximate composition of replacing fishmeal (Rastrineobola argentea) with a locally available spirulina species (Arthrospira fusiformis) as a protein ingredient in the feed of Rufiji tilapia (Oreochromis urolepis urolepis) fry was examined. Fishmeal replacement with A. fusiformis was carried out at 5%, 15%, 25%, 35% and 100% (S5, S15, S25, S35 and S100), and the effect of the replacement was compared with the control diet (S0, 0% spirulina). Fish fry were stocked at an average initial weight of 0.57 g at 10 fish per 0.1 m3 and cultured for 60 days using full strength salt water (30-35 ppt). A. fusiformis was isolated from Momela Lake in Arusha National Park, Tanzania and propagated using selected culture media. It was observed that fish fry fed spirulina at a 5% fishmeal substitution level diet had better (p&lt;0.05) final weight (8.48), average daily weight gain (0.132), specific growth rate (4.47), feed conversion rate (2.08) and protein efficiency ratio (1.37) compared to the control fish group. Growth performance in fish fed diet S15 was comparable with the control group (p&gt;0.05). Spirulina supplementation had no effect on fish survival rates and meat quality. It appears that the Momella Lake spirulina may be an appropriate growth-stimulating plant protein when used as a feed additive in Rufiji tilapia mariculture.

Effects of different types of manure on the culture of marine plankton as a potential source of food for mariculture hatcheries

The study examined different types of organic manure on the culture of marine plankton as a potential source of food for rabbitfish, Siganus stellatus, larvae. Cow dung showed significantly higher species abundance and diversity of cultured marine plankton followed by chicken and finally mixed media manure (p&lt;0.05). A total of 36 genera of phytoplankton (21) and zooplankton (15) were identified in all culture media. Class Bacillariophyta was the most abundant and diverse group which accounted for 41.3 % of the total phytoplankton. Calanoida was the dominant group of the identified zooplankton, accounting for 51.7 %. It was observed that the organic manure used favoured the growth of commercially important species of phytoplankton such as Chaetoceros sp., Skeletonema sp., Chlorella sp., Isochrysis sp., Nannochloropsis sp. and Spirulina sp., and zooplankton such as Eurytemora sp., Calanus sp., Oithona sp., Branchionus sp., Moina sp. and ostracods. The growth performance and survival rate of early stage rabbitfish larvae fed with live marine zooplankton performed better compared to those fed with Artemia spp. and commercial dry feed. This indicates that zooplankton have the potential to enhance growth performance and survival rate, hence increasing productivity and the development of mariculture

Digestibility of local feed ingredients in tilapia Oreochromis niloticus Juveniles, determined on faeces collected by siphoning or stripping

Eight locally available protein source ingredients in Tanzania were selected for assessment of apparent digestibility (AD) in tilapia Oreochromis niloticus, using faeces samples collected by siphoning or stripping. The selected protein source ingredients were Lake Victoria sardines (FM), brewers spent yeast (BSY), moringa leaves (ML), freshwater shrimp (FSH), marine shrimp (MSH), cattle blood (CB), duckweed (DW) and fish frames (FF). The AD (%) of dry matter (DM), organic matter (OM) and crude protein (CP) was unaffected (p > 0.782–0.901) by the faeces collection method (i.e., siphoning or stripping), with correlation coefficient (r) of 0.98, 0.99 and 0.93 between AD values for DM, OM and CP, respectively, following siphoning and stripping. The AD (%) of DM, OM, CP and gross energy (GE) in the test ingredients differed (p &lt; 0.0001). The AD (%) of DM and OM was lowest in BSY and DW, followed in increasing order by ML, MSH, FF, FSH and CB. In general, the AD (%) of CP was high (>76%), but with a low value (46%) for DW. The AD (%) of GE was closely correlated (r = 0.96) with the AD of OM. In conclusion, FSH, MSH, CB, FF, BSY and ML have acceptable protein digestibility to be used in tilapia diet formulation

Gene expression profiling in Pinus sylvestris after methyl jasmonate treatment

Šajā pētījumā noskaidrojām metiljasmonāta ietekmi uz parastās priedes gēnu ekspresijas profilu ar mērķi pārbaudīt tā potenciālu inducētas rezistences veidošanā. Divgadīgus viena klona parastās priedes stādus apstrādājām ar 10 mM metiljasmonāta un pēc divām nedēļām ievācām skuju paraugus. No iegūtajiem paraugiem izdalījām RNS un veicām nāk paaudzes sekvencēšanu ar Ion Torrent PGM platformu, kā arī RT-PCR ekspresijas pārbaudi atsevišķiem gēniem. Sekvencēšanā iegūtos datus analizējām ar RNA-Seq iegūstot paraugos ekspresēto gēnu profilu. Šos rezultātus apkopojām, veidojot gēnu tīklu un iegūstot funkcionalitātes anotācijas. Noskaidrojām, ka apstrāde novirza metabolisma orientāciju no augšanas un attīstības uz aizsardzību. Organisms atrodas inducētā stāvoklī divas nedēļas pēc apstrādes, kas aptiprina metiljasmonāta potenciālu inducētās rezistences veidošanā.In this research the effect of methyl jasmonate on the gene expression profile of Scots pine was determined in order to assess its potential to induce resistance. Two year old Scots pine ramets were treated with 10 mM methyl jasmonate and needle samples were collected two weeks after treatment. RNA was isolated from samples and transcription profiling was performed using the Ion Torrent PGM platform, as well as RT-PCR expression measurment for selected genes. Sequencing data were analyzed with RNA-Seq and gene expression profiles acquired. These results were summarized in a gene network and using gene functionality annotations. Results revealed that treatment with methyl jasmonate diverts metabolic functions from growth and development to defense. The organism is in an induced state two weeks after treatment, which confirms the potential of methyl jasmonate to cause induced resistance