Polychaetes of commercial interest from the Mediterranean East Coast of Algeria

Three species of polychaetous annelids are commercially collected, as baits, from natural populations along the coast of Algeria. They are collected by semi-professional bait harvesters supplying a variety of local outlets and are used as bait by local fishermen. Bait harvesters commonly use bleaching liquid (10% in sea water) or a KMnO4 (0.5 to 1% in sea water) solution to force Perinereis cultrifera (Nereididae) individuals out of their algal mat. Hediste diversicolor (Nereididae) and Scolelepis squamata(Spionidae) are dug from intertidal mudflats and sandy beaches. Commercial prices and ways of utilization are given for each species. The necessity for the legislative establishment of a regulatory management plan for worm angling is demonstrated

Efficient Algebraic Two-Level Schwarz Preconditioner for Sparse Matrices

Domain decomposition methods are among the most efficient for solving sparse linear systems of equations. Their effectiveness relies on a judiciously chosen coarse space. Originally introduced and theoretically proved to be efficient for self-adjoint operators, spectral coarse spaces have been proposed in the past few years for indefinite and non-self-adjoint operators. This paper presents a new spectral coarse space that can be constructed in a fully-algebraic way unlike most existing spectral coarse spaces. We present theoretical convergence result for Hermitian positive definite diagonally dominant matrices. Numerical experiments and comparisons against state-of-the-art preconditioners in the multigrid community show that the resulting two-level Schwarz preconditioner is efficient especially for non-self-adjoint operators. Furthermore, in this case, our proposed preconditioner outperforms state-of-the-art preconditioners

Doping Dependence of Thermal Oxidation on n-type 4H-SiC

The doping dependence of dry thermal oxidation rates in n-type 4H-SiC was investigated. The oxidation was performed in the temperature range 1000C to 1200C for samples with nitrogen doping in the range of 6.5e15/cm3 to 9.3e18/cm3, showing a clear doping dependence. Samples with higher doping concentrations displayed higher oxidation rates. The results were interpreted using a modified Deal-Grove model. Linear and parabolic rate constants and activation energies were extracted. Increasing nitrogen led to an increase in linear rate constant pre-exponential factor from 10-6m/s to 10-2m/s and the parabolic rate constant pre-exponential factor from 10e9m2/s to 10e6m2/s. The increase in linear rate constant was attributed to defects from doping-induced lattice mismatch, which tend to be more reactive than bulk crystal regions. The increase in the diffusion-limited parabolic rate constant was attributed to degradation in oxide quality originating from the doping-induced lattice mismatch. This degradation was confirmed by the observation of a decrease in optical density of the grown oxide films from 1.4 to 1.24. The linear activation energy varied from 1.6eV to 2.8eV, while the parabolic activation energy varied from 2.7eV to 3.3eV, increasing with doping concentration. These increased activation energies were attributed to higher nitrogen content, leading to an increase in effective bond energy stemming from the difference in C-Si (2.82eV) and Si-N (4.26eV) binding energies. This work provides crucial information in the engineering of SiO2 dielectrics for SiC MOS structures, which typically involve regions of very different doping concentrations, and suggests that thermal oxidation at high doping concentrations in SiC may be defect mediated.Comment: 13 pages. 9 figures, accepted as a transiction in IEEE electron device. TED MS#8035

Marine pollution effects on the reproduction process of Perinereis cultrifera (Annelida, Polychaeta) in Algeria

The Mediterranean Sea is one of the busiest areas worldwide in terms of maritime activity and faces considerable anthropogenic disturbances, such as pollution by hydrocarbons and heavy metals. This study evaluated the environmental status of three sites on the Algerian coast using the annelid polychaete Perinereis cultrifera as a biomonitoring sentinel species. It included different reproductive parameters such as oocyte diameter, frequency distributions, sexual maturity index, biochemical quantitative parameters represented by the vitellogenins and vitellins, and a histological study of the coelome during the reproductive period. The results showed that the females collected from El-Kala (healthy site) have the highest diameter 304.1 ± 24.3 μm during April but the values were increased in Annaba 290.0 ± 21.0 μm and Skikda 245.3 ± 26.7 μm. Significant differences were observed between worms from the three study sites during the three months of the study. Moreover, the size-frequency indicated that a relatively high proportion of females containing mature oocytes was found in April in females collected at El-Kala 52.4%, 46.4% in females collected at Annaba and 36.7% in females collected at Skikda. In addition, regarding the sexual maturity index, the highest values were recorded in April (3.8, 2.9, and 1.9) at the El-Kala, Annaba, and Skikda study sites. However, the biochemical analysis demontrated that the highest mean concentration of vitellogenin was in females of El-Kala (5.3 ± 0.3 µg/mg of coelomic fluid) in April, and the lowest mean concentration was measured in females of Skikda (1.5 ± 0.2 µg/mg of coelomic fluid). Therefore, the highest mean concentration of vitellin was measured in females of El-Kala (4.4 ± 0.2 µg/mg of oocytes) in April, while the lowest mean concentration of vitellin was measured in females of Skikda (1.02 ± 0.2 µg/mg of oocytes) in May. Significant differences were observed between worms from the three sites during the three months of the study. Furthermore, histological observations revealed that oogenesis was asynchronous, with oocytes at different stages of vitellogenesis simultaneously present. The structure of the oocytes of females collected at El-Kala showed intense vitellogenic activity due to the presence of very dense yolk cells. In contrast, the oocytes of the females collected from the two polluted sites (Annaba and Skikda) were small, vitellogenesis presented low intensity, and yolk cells were less frequent at the periphery and less uniform at the cytoplasmic mass; the nucleus was smaller, indicating a slower vitellogenic activity. These observations confirm the previously obtained results

How fast is fast enough? Academic behavioural science impacting public health policy and practice

Background: COVID-19 emphasised the crucial role behaviour change plays in protecting population health. However, the interchange between academic behavioural science and Public Health (PH) policy and practice could be strengthened. We aimed to establish a sustainable method of joint working between two groups in North Scotland to enable rapid impact of behavioural science on population health.Methods: An implementation-sciences based approach tested the initial 4 steps of an 8-step collaboration process model, designed to identify a health problem (step 1), develop and test messaging interventions (step 2-4), implement the intervention (steps 5-6), and evaluate impact (steps 7-8).Results: Since October 2022, fortnightly meetings were established, implementing the process model. This project will focus on the following outcomes: perceived collaboration usefulness, collaboration-process barriers, and facilitators.Conclusions: Unless a sustainable method of joint working can be established in times where there are no urgent PH priorities, it is unlikely that the fruits of behavioural science can be aligned with PH challenges when outbreaks are happening to rapidly impact population health.<br/

How fast is fast enough? Academic behavioural science impacting public health policy and practice

Background: COVID-19 emphasised the crucial role behaviour change plays in protecting population health. However, the interchange between academic behavioural science and Public Health (PH) policy and practice could be strengthened. We aimed to establish a sustainable method of joint working between two groups in North Scotland to enable rapid impact of behavioural science on population health.Methods: An implementation-sciences based approach tested the initial 4 steps of an 8-step collaboration process model, designed to identify a health problem (step 1), develop and test messaging interventions (step 2-4), implement the intervention (steps 5-6), and evaluate impact (steps 7-8).Results: Since October 2022, fortnightly meetings were established, implementing the process model. This project will focus on the following outcomes: perceived collaboration usefulness, collaboration-process barriers, and facilitators.Conclusions: Unless a sustainable method of joint working can be established in times where there are no urgent PH priorities, it is unlikely that the fruits of behavioural science can be aligned with PH challenges when outbreaks are happening to rapidly impact population health.<br/