10,850 research outputs found
Résidus de pesticides organochlorés chez les bivalves et les poissons de la lagune de Moulay Bousselham (Maroc)
Oragnochlorine pesticide residues in bivalves and fishes fromthe Moulay Bousselham lagoon (Morocco) This work involves an assessment of the degree of contamination by Organochlorine pesticides (POC) of clams (Venerupis deccusatua), mussels (Mytilus edulis) and fish mullet (Mugil cephalus) from the Moulay Bousselham lagoon. 12 organochlorine pesticides are considered in this study: DDT and its metabolites (DDD, DDE), ƒÁHCH and ƒ¿HCH, aldrin, endrin, dieldrin, heptachlor, heptachlor epoxide, hexachlorobenzene (HCB) and ƒ¿ endosulfan. The study showed an important contamination by organochlorine pesticides, DDT and its metabolites present the high concentrations at all species, lindane and its isomers are also present but at low concentrations. At clams, concentrations of POC varied between 9.2 to 51.72 ng/g (dry weight) with a maximum detected in the station of oued Drader. Mussels were less contaminated that clams, concentrations varied between 4.53 to 16.81 ng/g. The contamination of mullet by POC is more marked with a concentrations varied between 12.52 ng/g recorded in November to 82.39 ng/g detected in May. The strong proportion of DDE in relation to DDT showed that the major ofcontamination is very old. The quantities of organochlorine pesticides revealed at clams, mussels and mulled of Moulay Bousselham lagoon don’t exceed the maximal limits in marines organisms. The consumption of these species don’t have actually any problem in public health
Assessing the Climate-Smartness of the West Africa Agricultural Productivity Programme (WAAPP): What can we learn from Benin, Guinea, Niger, Togo and Chad projects?
This info note summarizes the findings from participatory assessments of the climate-smartness of World Bank
funded West Africa Agricultural Productivity Programme (WAAPP)”. This activity was implemented by CCAFS West Africa regional programme in partnership with CORAF under the Capacitating Stakeholders in Using Climate Information for Enhanced Resilience in the Agricultural Sector in West Africa (CaSCIERA-WA) project to strengthen the capacity of country stakeholders of WAAPP to mainstream and implement CSA in their activities in West Africa
Two-photon double ionization of neon using an intense attosecond pulse train
We present the first demonstration of two-photon double ionization of neon
using an intense extreme ultraviolet (XUV) attosecond pulse train (APT) in a
photon energy regime where both direct and sequential mechanisms are allowed.
For an APT generated through high-order harmonic generation (HHG) in argon we
achieve a total pulse energy close to 1 J, a central energy of 35 eV and a
total bandwidth of eV. The APT is focused by broadband optics in a
neon gas target to an intensity of Wcm. By tuning
the photon energy across the threshold for the sequential process the double
ionization signal can be turned on and off, indicating that the two-photon
double ionization predominantly occurs through a sequential process. The
demonstrated performance opens up possibilities for future XUV-XUV pump-probe
experiments with attosecond temporal resolution in a photon energy range where
it is possible to unravel the dynamics behind direct vs. sequential double
ionization and the associated electron correlation effects
Time-resolved photoelectron and photoion fragmentation spectroscopy study of 9-methyladenine and its hydrates: a contribution to the understanding of the ultrafast radiationless decay of excited DNA bases.
The excited state dynamics of the purine base 9-methyladenine (9Me-Ade) has been investigated by time- and energy-resolved photoelectron imaging spectroscopy and mass-selected ion spectroscopy, in both vacuum and water-cluster environments. The specific probe processes used, namely a careful monitoring of time-resolved photoelectron energy distributions and of photoion fragmentation, together with the excellent temporal resolution achieved, enable us to derive additional information on the nature of the excited states (pp*, np*, ps*, triplet) involved in the electronic relaxation of adenine. The two-step pathway we propose to account for the double exponential decay observed agrees well with recent theoretical calculations. The near-UV photophysics of 9Me-Ade is dominated by the direct excitation of the pp* (1Lb) state (lifetime of 100 fs), followed by internal conversion to the np* state (lifetime in the ps range) via conical intersection. No evidence for the involvement of a ps* or a triplet state was found. 9Me- Ade–(H2O)n clusters have been studied, focusing on the fragmentation of these species after the probe process. A careful analysis of the fragments allowed us to provide evidence for a double exponential decay profile for the hydrates. The very weak second component observed, however, led us to conclude that the photophysics were very different compared with the isolated base, assigned to a competition between (i) a direct one-step decay of the initially excited state (pp* La and/or Lb, stabilised by hydration) to the ground state and (ii) a modified two-step decay scheme, qualitatively comparable to that occurring in the isolated molecule
Ascaris phylogeny based on multiple whole mtDNA genomes
Ascaris lumbricoides and A. suum are two parasitic nematodes infecting humans and pigs, respectively. There has been considerable debate as to whether Ascaris in the two hosts should be considered a single or two separate species. Previous studies identified at least three major clusters (A, B and C) of human and pig Ascaris based on partial cox1 sequences. In the present study, we selected major haplotypes from these different clusters to characterize their whole mitochondrial genomes for phylogenetic analysis. We also undertook coalescent simulations to investigate the evolutionary history of the different Ascaris haplotypes. The topology of the phylogenetic tree based on complete mitochondrial genomic sequences was found to be similar to partial cox1 sequencing, but the support at internal nodes was higher in the former. Coalescent simulations suggested the presence of at least two divergence events: the first one occurring early in the Neolithic period which resulted in a differentiated population of Ascaris in pigs (cluster C), the second occurring more recently (~ 900 generations ago), resulting in clusters A and B which might have been spread worldwide by human activities
Feasibility of diffusion and probabilistic white matter analysis in patients implanted with a deep brain stimulator.
Deep brain stimulation (DBS) for Parkinson\u27s disease (PD) is an established advanced therapy that produces therapeutic effects through high frequency stimulation. Although this therapeutic option leads to improved clinical outcomes, the mechanisms of the underlying efficacy of this treatment are not well understood. Therefore, investigation of DBS and its postoperative effects on brain architecture is of great interest. Diffusion weighted imaging (DWI) is an advanced imaging technique, which has the ability to estimate the structure of white matter fibers; however, clinical application of DWI after DBS implantation is challenging due to the strong susceptibility artifacts caused by implanted devices. This study aims to evaluate the feasibility of generating meaningful white matter reconstructions after DBS implantation; and to subsequently quantify the degree to which these tracts are affected by post-operative device-related artifacts. DWI was safely performed before and after implanting electrodes for DBS in 9 PD patients. Differences within each subject between pre- and post-implantation FA, MD, and RD values for 123 regions of interest (ROIs) were calculated. While differences were noted globally, they were larger in regions directly affected by the artifact. White matter tracts were generated from each ROI with probabilistic tractography, revealing significant differences in the reconstruction of several white matter structures after DBS. Tracts pertinent to PD, such as regions of the substantia nigra and nigrostriatal tracts, were largely unaffected. The aim of this study was to demonstrate the feasibility and clinical applicability of acquiring and processing DWI post-operatively in PD patients after DBS implantation. The presence of global differences provides an impetus for acquiring DWI shortly after implantation to establish a new baseline against which longitudinal changes in brain connectivity in DBS patients can be compared. Understanding that post-operative fiber tracking in patients is feasible on a clinically-relevant scale has significant implications for increasing our current understanding of the pathophysiology of movement disorders, and may provide insights into better defining the pathophysiology and therapeutic effects of DBS
Ovarian Cancer in the Sudan - Identifying the Social and Clinical Factors that Prevent an Early Diagnosis
Ovarian cancer, because it often presents with vague symptoms, is a difficult disease to diagnose at the early stages, especially in developing countries. In Sudan, diagnosis is further complicated by additional factors and challenges. First, as in any developing country, access to treatment, facilities and medical staff is generally lacking. Secondly, Sudan is the second largest country in Africa: its very size presents difficulties for the implementation of a centralized health system. The two tertiary hospitals in or near the capital have long patient waiting lists.The lack of female education in sub-Saharan Africa, together with social and economic issues affecting women, is a further obstacle to disease diagnosis and management. Misdiagnosis, leading to inappropriate treatment, may result from the presence of comorbid diseases such as Tuberculosis (TB), which can mimic ovarian cancer and obstruct early detection. Most patients are identified at the later stages when the complications associated with invasive procedures and conventional chemotherapy make treatment much less effective. The early detection of biomarkers may prove to be a vital tool to indicate targets for immunotherapy treatment.Financial aid may help improve the outcomes for patients with ovarian cancer in the Sudan, assisting with diagnosing and management procedures including training medical staff. Research and development, documentation and updating the statistical register for the whole country are also important requirements for future improvements.Finally, there is a need to promote interdisciplinary work between surgeons and clinical oncologists to optimize international guidelines and protocols in accordance with the facilities available
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