Disa’ sinfonija ta’ Beethoven

Ġabra ta’ poeżiji u proża li tinkludi: It-trabokk ta’ W. Borg – Il-merħla tal-bnedmin ta’ Pawlu Aquilina – Versi ta’ Marċell Mizzi – Fuq ix-xmara Mersey, Manchester ta’ Wallace Ph. Gulia – Ħolma ta’ Peter A. Caruana – “Ma jiġix iżjed” ta’ A. Tabone – Id-dinja u l-bniedem ta’ Ġużè Chetcuti – Il-ġlied tal-ħbieb ta’ Marċell Mizzi – Lil ibni Danjel ta’ Manwel Cassar – Li kieku!!! ta’ C. Cassar – Id-disa’ sinfonija ta’ Beethoven ta’ Karmenu Mallia.peer-reviewe

Coupled free-carrier and exciton relaxation in optically excited semiconductors

The energy relaxation of coupled free-carrier and exciton populations in semiconductors after low-density ultrafast optical excitation is studied through a kinetic approach. The set of semiclassical Boltzmann equations, usually written for electron and hole populations only, is complemented by an additional equation for the exciton distribution. The equations are coupled by reaction terms describing phonon-mediated exciton binding and dissociation. All the other relevant scattering mechanisms, such as carrier-carrier, carrier-phonon, and exciton-phonon interactions, are also included. The resulting system of rate equations in reciprocal space is solved by an extended ensemble Monte Carlo method. As a first application, we show results for the dynamics of bulk GaAs in the range from 1 to ∼200 ps after photoexcitation. The build-up of an exciton population and its sensitivity to the excitation conditions are discussed in detail. As a consequence of the pronounced energy dependence of the LO-phonon-assisted transition probabilities between free-pair states and excitons, it is found that the efficiency of the exciton-formation process and the temporal evolution of the resulting population are sensitive to the excitation energy. We discuss the effects on luminescence experiments

The Neuropeptide Allatostatin A Regulates Metabolism and Feeding Decisions in Drosophila

Coordinating metabolism and feeding is important to avoid obesity and metabolic diseases, yet the underlying mechanisms, balancing nutrient intake and metabolic expenditure, are poorly understood. Several mechanisms controlling these processes are conserved in Drosophila, where homeostasis and energy mobilization are regulated by the glucagon-related adipokinetic hormone (AKH) and the Drosophila insulin-like peptides (DILPs). Here, we provide evidence that the Drosophila neuropeptide Allatostatin A (AstA) regulates AKH and DILP signaling. The AstA receptor gene, Dar-2, is expressed in both the insulin and AKH producing cells. Silencing of Dar-2 in these cells results in changes in gene expression and physiology associated with reduced DILP and AKH signaling and animals lacking AstA accumulate high lipid levels. This suggests that AstA is regulating the balance between DILP and AKH, believed to be important for the maintenance of nutrient homeostasis in response to changing ratios of dietary sugar and protein. Furthermore, AstA and Dar-2 are regulated differentially by dietary carbohydrates and protein and AstA-neuronal activity modulates feeding choices between these types of nutrients. Our results suggest that AstA is involved in assigning value to these nutrients to coordinate metabolic and feeding decisions, responses that are important to balance food intake according to metabolic needs

Adoption of children and young persons

In this paper it is intended to give a quick bird's eye view look at the trends relating to adoption. In such a quick survey most of the details will elude us, but the broad currents will obviously come to the fore.peer-reviewe

Egħluq is-sena mill-ingress ta’ l-Arċisqof

Ġabra ta’ poeżiji u proża li tinkludi: Il-Kotra u Jiena ta’ Rużar Briffa – Naħarbu ta’ W. Ph. Gulia – Tliet Imħabbiet ta’ Vic. Apap – Lhudija ta’ Louis Ellul – Imqarraq ta’ Ġ. M. Farrugia – Hekk Kien Miktub ta’ A. Cremona – Land of Hope and Glory ta’ Ivo Muscat Azzopardi – Villa Lija ta’ Marju Agius – Fuq Kemmuna ta’ Ġ. Cassar Pullicino – Ħolqien u Qirda ta’ E. Agius – Egħluq is-sena mill-ingress ta’ l-Arċisqof ta’ Amante Buontempo.N/