Polycyclic Aromatic Hydrocarbons (PAHs) and Their Influence to Some Aquatic Species

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants generated primarily during the incomplete combustion of organic materials (e.g., coal, oil, petrol, and wood). Many PAHs have toxic, mutagenic, and/or carcinogenic functions. PAHs are highly lipid soluble which lead to a fast absorption by the gastrointestinal tract of marine mammals. They are immediately distributed in a vast variety of tissues with a notable tendency for localization in body fat. Metabolism of PAHs is obtained via the cytochrome P450-mediated mixed function oxidase system with oxidation or hydroxylation as the first step. PAHs are environmental contaminants that pose significant risk to health of fish. The effect of PAHs on fish is a topic of rising attention in a lot of countries. Different studies using the bile metabolites separated by high-performance liquid chromatography with fluorescence detection were presented. The aim is to compare the levels of PAH metabolites in fish from different areas and fish species. The major metabolite present in all fish was 1-hydroxypyrene. The data confirm the importance of 1-hydroxypyrene as the key PAH metabolite in fish bile and suggest that the European eel is an ideal species for monitoring PAHs

High Genetic Diversity and Clonal Growth in Relict Populations of Olea europaea subsp. laperrinei (Oleaceae) from Hoggar, Algeria

• Background and Aims The Laperrine's olive (Olea europaea subsp. laperrinei) is an endemic tree from Saharan massifs. Its populations have substantially regressed since the Pleistocene and are presently distributed in a fragmented habitat. Long-term persistence of this taxon is uncertain and programmes of preservation have to be urgently implemented. To define a conservation strategy, the genetic diversity and breeding system of this tree have to be investigated. • Methods One hundred and eleven ramets were prospected in the laperrinei populations from the Tamanrasset region, southern Algeria. Genetic polymorphism was revealed at nuclear and chloroplast DNA (cpDNA) microsatellite loci allowing a comparative assessment of the genetic diversity of laperrinei and Mediterranean populations based on bi-parental and maternal markers. Additionally, nuclear microsatellite markers enabled the genotypes to be identified unambiguously. • Key Results Based on nuclear microsatellite data, the total diversity was high (Ht = 0·61) in laperrinei populations and similar to that observed in western Mediterranean populations. A substantial cpDNA diversity (Ht = 0·19) was also observed. Genetically identical ramets originated from the same stump (which can cover >80 m2) were identified in each population. Sixteen per cent of genets exhibited more than one ramet. In addition, several cases of somatic mutations were unambiguously revealed in distinct ramets stemming from the same stump. • Conclusions These data show that highly isolated and small laperrinei populations are able to maintain a high genetic diversity. This supports the existence of relict trees persisting for a very long time (probably since the last humid transition, 3000 years ago). It is proposed that the very long persistence associated with an asexual multiplication of highly adapted trees could be a strategy of survival in extreme conditions avoiding a mutational meltdown due to reproduction in reduced population

High genetic diversity and clonal growth in relict populations of Olea europaea subsp. laperrinei (Oleaceae) from Hoggar, Algeria.

The Laperrine's olive (Olea europaea subsp. laperrinei) is an endemic tree from Saharan massifs. Its populations have substantially regressed since the Pleistocene and are presently distributed in a fragmented habitat. Long-term persistence of this taxon is uncertain and programmes of preservation have to be urgently implemented. To define a conservation strategy, the genetic diversity and breeding system of this tree have to be investigated. One hundred and eleven ramets were prospected in the laperrinei populations from the Tamanrasset region, southern Algeria. Genetic polymorphism was revealed at nuclear and chloroplast DNA (cpDNA) microsatellite loci allowing a comparative assessment of the genetic diversity of laperrinei and Mediterranean populations based on bi-parental and maternal markers. Additionally, nuclear microsatellite markers enabled the genotypes to be identified unambiguously. Based on nuclear microsatellite data, the total diversity was high (Ht=0.61) in laperrinei populations and similar to that observed in western Mediterranean populations. A substantial cpDNA diversity (Ht=0.19) was also observed. Genetically identical ramets originated from the same stump (which can cover >80 m2) were identified in each population. Sixteen per cent of genets exhibited more than one ramet. In addition, several cases of somatic mutations were unambiguously revealed in distinct ramets stemming from the same stump. These data show that highly isolated and small laperrinei populations are able to maintain a high genetic diversity. This supports the existence of relict trees persisting for a very long time (probably since the last humid transition, 3000 years ago). It is proposed that the very long persistence associated with an asexual multiplication of highly adapted trees could be a strategy of survival in extreme conditions avoiding a mutational meltdown due to reproduction in reduced populations

Effect of Insertion Viscoelastic Damping Layer with Different Thicknesses on the Dynamic Response of Multi-layered Beam in Forced Vibration

In this work, we study the effect of the thickness variation of viscoelastic layer inserted in a laminated multi-layer beam in forced vibration on the vertical displacements and on the natural frequencies. The new structure is a sandwich structure composed by two external layers (top and bottom facesheets) of aluminum and viscoelastic core of 3M ISD112 polymers. The viscoelastic model used to describe the behavior of the core is a four-parameter fractional derivative model. The finite element method including the viscoelastic model of fractional derivatives for modeling the sandwich structure is used. The system resolution of the nonlinear equations of motion of the sandwich structure is required to use a numerical integration method as the explicit method of Newmark to obtain the transient response. Also, ANSYS finite element modeling is applied to the sandwich structure to calculate the frequency response in harmonic vibration. The increase in the thickness of the viscoelastic layer leads to a decrease in the amplitudes of vibration. The natural frequencies found by the two methods are very close to the frequencies found experimentally in the literature

Mise En Evidence D’une Alternance D’episodes Climatiques Pendant La Fin Du Pleistocene Superieur : Enregistrements Dans Les Depots Lacustres De Dayet Iffere (Moyen Atlas, Maroc)

In northern Middle Atlas, the Dayet Iffère is located in an area affected by karst and tectonic. After its watershed genesis of middle altitude during the upper Pleistocene, two lacustrine formation were deposed. The detailed sedmentological study as well as the correlations between the different lacustrine formations defined in Dayet Afourgagh and Dayet Agoulmam, and the 14C dating allowed to reconstitute the major stages of the filling evolution of the lake basin and its sedimentary dynamic. The variations of sedimentation are interpreted as climatic fluctuations and evolution of vegetation since upper Soltanien. These results show a complex interaction between sedimentary processes and climatic phenomena that tend to a stability marked by heat, permanent humidity and a fairly dense vegetation cover at the end of the Soltanian, after probably a hot arid to semi-arid episode

La pratique contraceptive dans la Wilaya de Marrakech (Maroc): niveau, but, évolution et relation avec la fécondité

consultable sur http://bmsap.revues.org/document1843.htmlLe comportement de planification familiale a été analysé dans deux communautés de la Wilaya de Marrakech (Maroc), l'une urbaine représentée par la ville de Marrakech et l'autre rurale représentée par quelques communes d'Amizmiz (cercle d'Amizmiz, province du Haouz, Wilaya de Marrakech). D'une manière générale, le recours à la contraception est assez important mais il est nettement plus élevé en milieu urbain. L'analyse des biographies contraceptives et particulièrement de la période d'entrée en vie contraceptive et de la régularité dans l'utilisation des méthodes de contraception, fait ressortir les intentions des femmes à l'usage de la contraception. La contraception adoptée en milieu urbain est une attitude quasi exclusivement d'espacement entre les naissances et où la régularité est de rigueur. Tandis qu'en milieu rural coexistent deux attitudes liées à l'usage de la contraception : l'espacement et la limitation de la procréation. La diffusion de la contraception a débuté en 1965 pour la ville et en 1975 pour le milieu rural. Le rythme de transition de la contraception a ensuite été très progressif en milieu urbain et très accéléré en milieu rural. D'autres différences sont mises en évidence entre les deux milieux, concernant l'évolution de la pratique contraceptive au cours de la vie génésique des femmes. L'efficacité de la contraception sur les niveaux de fécondité est prouvée

DriveWays: a method for identifying possibly overlapping driver pathways in cancer

The majority of the previous methods for identifying cancer driver modules output nonoverlapping modules. This assumption is biologically inaccurate as genes can participate in multiple molecular pathways. This is particularly true for cancer-associated genes as many of them are network hubs connecting functionally distinct set of genes. It is important to provide combinatorial optimization problem definitions modeling this biological phenomenon and to suggest efficient algorithms for its solution. We provide a formal definition of the Overlapping Driver Module Identification in Cancer (ODMIC) problem. We show that the problem is NP-hard. We propose a seed-and-extend based heuristic named DriveWays that identifies overlapping cancer driver modules from the graph built from the IntAct PPI network. DriveWays incorporates mutual exclusivity, coverage, and the network connectivity information of the genes. We show that DriveWays outperforms the state-of-the-art methods in recovering well-known cancer driver genes performed on TCGA pan-cancer data. Additionally, DriveWay's output modules show a stronger enrichment for the reference pathways in almost all cases. Overall, we show that enabling modules to overlap improves the recovery of functional pathways filtered with known cancer drivers, which essentially constitute the reference set of cancer-related pathways.No sponso

La pratique contraceptive dans la Wilaya de Marrakech (Maroc): niveau, but, évolution et relation avec la fécondité

consultable sur http://bmsap.revues.org/document1843.htmlLe comportement de planification familiale a été analysé dans deux communautés de la Wilaya de Marrakech (Maroc), l'une urbaine représentée par la ville de Marrakech et l'autre rurale représentée par quelques communes d'Amizmiz (cercle d'Amizmiz, province du Haouz, Wilaya de Marrakech). D'une manière générale, le recours à la contraception est assez important mais il est nettement plus élevé en milieu urbain. L'analyse des biographies contraceptives et particulièrement de la période d'entrée en vie contraceptive et de la régularité dans l'utilisation des méthodes de contraception, fait ressortir les intentions des femmes à l'usage de la contraception. La contraception adoptée en milieu urbain est une attitude quasi exclusivement d'espacement entre les naissances et où la régularité est de rigueur. Tandis qu'en milieu rural coexistent deux attitudes liées à l'usage de la contraception : l'espacement et la limitation de la procréation. La diffusion de la contraception a débuté en 1965 pour la ville et en 1975 pour le milieu rural. Le rythme de transition de la contraception a ensuite été très progressif en milieu urbain et très accéléré en milieu rural. D'autres différences sont mises en évidence entre les deux milieux, concernant l'évolution de la pratique contraceptive au cours de la vie génésique des femmes. L'efficacité de la contraception sur les niveaux de fécondité est prouvée

Étude fonctionnelle des domaines structuraux des sous-unités catalytiques de l'ARN polymérase II humaine

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal