Diode-pumped ultrafast Yb:KGW laser with 56 fs pulses and multi-100 kW peak power based on SESAM and Kerr-lens mode locking

A high-power sub-60 fs mode-locked diode-pumped Yb:KGW laser based on hybrid action of an InGaAs quantum-dot saturable absorber mirror and Kerr-lens mode locking was demonstrated. The laser delivered 56 fs pulses with 1.95 W of average power corresponding to 450 kW of peak power. The width of the generated laser spectrum was 20.5 nm, which was near the gain bandwidth limit of the Yb:KGW crystal. To the best of our knowledge, these are the shortest pulses generated from the monoclinic double tungstate crystals (and Yb:KGW laser crystal in particular) and the most powerful in the sub-60 fs regime. At the same time, they are also the shortest pulses produced to date with the help of a quantum-dot-based saturable absorber. High-power operation with a pulse duration of 90 fs and 2.85 W of average output power was also demonstrated

Analyses of an Expressed Sequence Tag Library from Taenia solium, Cysticerca

A method used to describe expressed genes at a specific stage in an organism is an EST library. In this method mRNA from a specific organism is isolated, transcribed into cDNA and sequenced. The sequence will derive from the 5′-end of the cDNA. The library will not have sequences from all genes, especially if they are expressed in low amounts or not at all in the studied stage. Also the library will mostly not contain full length sequences from genes, but expression patterns can be established. If EST libraries are made from different stages of the same organisms these libraries can be compared and differently expressed genes can be identified. Described here is an analysis of an EST library from the pig cysticerca which is thought to be similar to the stage giving the human neglected disease neurocysticercosis. Novel genes together with putative drug targets are examples of data presented

Biochar successfully replaces activated charcoal for in vitro culture of two white poplar clones reducing ethylene concentration

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Influence of environmental health services on students’ academic performance in Secondary Schools in Bayelsa State

The study investigated the effect of environmental health services on students’ academic performance in secondary schools in Brass Local Government Area of Bayelsa State. The study adopted the descriptive survey design. The sample for the study comprised a total of 245 students and 59 teachers, amounting to 304 respondents. The instrument used was a researchers’ developed questionnaire titled, “Environmental Health Services and Students’ Academic Performance Questionnaire (EHSSAPQ)” which was validated by two experts in measurement and evaluation. Reliability of the instrument was established using Pearson Product Moment Correlation technique and a reliability coefficient of 0.71 was obtained. Four research questions and four hypotheses tested at 0.05 Alpha levels guided the conduct of the study. Data analysis was done using frequent count, percentages and chi-square. The result show that higher percentages of the respondents were of the opinion that portable water, drainage system and waste disposal do not affect students’ academic performance, except for first aid where teachers affirmed that it affected academic performance. The test of hypotheses revealed significant effects of portable water and first aid treatment on students’ academic performance with chi-square values of 4.00 and 16.23 respectively. Based on the findings, recommendations were made that portable water and first aid treatment be made available in schools.Keywords: Environmental health services, academic performance, secondary school