Illite K–Ar dating and crystal growth processes in diagenetic environments: a critical review

K–Ar dating of illitic minerals is commonly used in studies of diagenetic series applied to oil prospecting. In spite of a great number of specialized papers, some problems remain unresolved. These are mostly due to a misunderstanding of the argon accumulation process during illitization. Criteria for identifying detrital–authigenic mineral mixtures, crystal ripening, fast precipitation or continuous nucleation-growth processes are discussed using K–Ar data available in the literature. Using different parameters, such as Dage (age K–Ar ) age strati), D cryst (diagenetic ageK–Ar ) age strati) or D frac (age K–Arfraction ) age K–Ar finest), it is shown that the K–Ar age significance depends on the illite nucleation–growth processes. A ‘diagenetic age’ is obtained when these processes are rapid (the K2O accumulation period is shorter than 2r). If lower than this value, the K–Ar ratio depends on the proportions of new and old particles, respectively, which are controlled by the relative rates of nucleation, crystal growth and ripening

Quantitative cognition in carpenter ants

P.dE. is funded by ‘Institut Universitaire de France (IUF)’.Processing information about quantities allows animals to make optimal decisions during many natural contexts, such as foraging, territorial defense, offspring care, mate choice, and intra-sexual competition. Compared to the wealth of information available in vertebrates, much less is known in invertebrates, even though the processing of quantities is equally relevant for both taxa. Here, we used two separate ecologically relevant tasks (brood pile preference and landmark-guided foraging) to investigate two dimensions of quantitative cognition in carpenter ants: spontaneous quantitative judgments and trained use of sequential landmarks. Individual ants spontaneously discriminated between two piles of dummy cocoons both when the choice involved smaller (1 vs. 2, 3, 4) and larger numerical contrasts (2 vs. 4, 6, 8). Ants used both chemical and visual/tactile cues and their performance was dependent on the numerical ratio. In the second task, ants preferentially searched near the trained landmark (out of five identical ones) despite alterations in its position, suggesting that they used ordinal information about its location when searching for food. In this experiment, ants showed a limit at four since their performance drastically decreased when they were trained to the 5th landmark. We showed that carpenter ants use both relative quantity and relative position to make efficient decisions. Our study contributes to the scant body of knowledge available on quantitative cognition in invertebrate species.PostprintPeer reviewe

vanA in Enterococcus faecium, Enterococcus faecalis, and Enterococcus casseliflavus detected in French cattle.

The goal of this study was to assess the presence of enterococci species presenting van-mediated glycopeptide resistance in French cattle. Fecal samples were collected from healthy and sick animals, and enterococci were screened for vancomycin resistance. Vancomycin resistance was principally encountered in Enterococcus gallinarum and Enterococcus casseliflavus strains. However, glycopeptide resistance was detected in three different species of enterococci (E. faecalis, E. faecium, and E. casseliflavus). Molecular characterization of the genetic support proved that they all presented the prototypic VanA element. Interestingly, the E. casseliflavus strain displayed a remarkable VanB phenotype/vanA-vanC genotype. Transferability, associated resistances, and factors of vanA cotransfer were sought. This study proved that acquired vanA genes can still be detected in food-producing animals more than a decade after the avoparcin ban. Indeed, calves, which are recurrently exposed to antibiotics in France, may allow the re-emergence of glycopeptide resistance through coselection factors, and this might potentially be concerning for human health

Middle Permian Telodiagenetic Processes in Neoproterozoic Sequences, Tandilia System, Argentina

In the Tandilia Basin, Buenos Aires Province, Argentina, we study the genesis of mud beds and pipes in the Loma Negra Formation (limestones), Sierras Bayas area, together with the emplacement of alunite and aluminum phosphate sulfate (APS) minerals in the Las Aguilas Formation, Barker area. All these features are related to basin inversion, uplift, erosion, and injection or expulsion, or infiltration of fluids and oxidation reactions in the exhumed rocks during a telodiagenetic stage. On the basis of K--Ar dating of alunite in the Las Aguilas Formation (claystones) giving an age of 254 ± 7 Ma (middle Permian), these processes are considered to be linked to a major geological event which affected these Neoproterozoic lithostratigraphic units: the folding of the Ventania System, located 150 km to the SW of the study area.Centro de Tecnología de Recursos Minerales y Cerámic

BMP-2 signaling in ovarian cancer and its association with poor prognosis

BACKGROUND: We previously observed the over-expression of BMP-2 in primary cultures of epithelial ovarian cancer (EOC) cells as compared to normal epithelial cells based on Affymetrix microarray profiling [1]. Here we investigate the effect of BMP-2 on several parameters of ovarian cancer tumorigenesis using the TOV-2223, TOV-1946 and TOV-112D EOC cell lines. METHODS: We treated each EOC cell line with recombinant BMP-2 and assayed various parameters associated with tumorigenesis. More specifically, cell signaling events induced by BMP-2 treatment were investigated by western-blot using anti-phosphospecific antibodies. Induction of Id1, Snail and Smad6 mRNA expression was investigated by real time RT-PCR. The ability of cells to migrate was tested using the scratch assay. Cell-cell adhesion was analyzed by the ability of cells to form spheroids. We also investigated BMP-2 expression in tissue samples from a series of EOC patients. RESULTS: Treatment of these cell lines with recombinant BMP-2 induced a rapid phosphorylation of Smad1/5/8 and Erk MAPKs. Increased expression of Id1, Smad6 and Snail mRNAs was also observed. Only in the TOV-2223 cell line were these signaling events accompanied by an alteration in cell proliferation. We also observed that BMP-2 efficiently increased the motility of all three cell lines. In contrast, BMP-2 treatment decreased the ability of TOV-1946 and TOV-112D cell lines to form spheroids indicating an inhibition of cell-cell adhesion. The expression of BMP-2 in tumor tissues from patients was inversely correlated with survival. CONCLUSION: These results suggest that EOC cell secretion of BMP-2 in the tumor environment contributes to a modification of tumor cell behavior through a change in motility and adherence. We also show that BMP-2 expression in tumor tissues is associated with a poorer prognosis for ovarian cancer patients

Risk Factors for Marburg Hemorrhagic Fever, Democratic Republic of the Congo

We conducted two antibody surveys to assess risk factors for Marburg hemorrhagic fever in an area of confirmed Marburg virus transmission in the Democratic Republic of the Congo. Questionnaires were administered and serum samples tested for Marburg-specific antibodies by enzyme-linked immunosorbent assay. Fifteen (2%) of 912 participants in a general village cross-sectional antibody survey were positive for Marburg immunoglobulin G antibody. Thirteen (87%) of these 15 were men who worked in the local gold mines. Working as a miner (odds ratio [OR] 13.9, 95% confidence interval [CI] 3.1 to 62.1) and receiving injections (OR 7.4, 95% CI 1.6 to 33.2) were associated with a positive antibody result. All 103 participants in a targeted antibody survey of healthcare workers were antibody negative. Primary transmission of Marburg virus to humans likely occurred via exposure to a still unidentified reservoir in the local mines. Secondary transmission appears to be less common with Marburg virus than with Ebola virus, the other known filovirus

Aging is associated with a prefrontal lateral-medial shift during picture-induced negative affect

The capacity to adaptively respond to negative emotion is in part dependent upon lateral areas of the prefrontal cortex (PFC). Lateral PFC areas are particularly susceptible to age-related atrophy, which affects executive function (EF). We used structural and functional magnetic resonance imaging (MRI) to test the hypothesis that older age is associated with greater medial PFC engagement during processing of negative information, and that this engagement is dependent upon the integrity of grey matter structure in lateral PFC as well as EF. Participants (n = 64, 38–79 years) viewed negative and neutral scenes while in the scanner, and completed cognitive tests as part of a larger study. Grey matter probability (GMP) was computed to index grey matter integrity. FMRI data demonstrated less activity in the left ventrolateral PFC (VLPFC) and greater ventromedial PFC (VMPFC) activity with increasing age during negative-picture viewing. Age did not correlate with amygdala responding. GMP in VLPFC and EF were negatively associated with VMPFC activity. We conclude that this change from lateral to medial PFC engagement in response to picture-induced negative affect reflects decreased reliance on executive function-related processes, possibly associated with reduced grey matter in lateral PFC, with advancing age to maintain emotional functioning

Simultaneous eradications of Black Rat (Rattus rattus) and Ice plants (Carpobrotus spp.) on Bagaud Island (Port-Cros National Park, Provence, France): preliminary results on their impacts on Athropods communities

Les invasions biologiques sont reconnues comme l’une des principales menaces pour la conservation de la biodiversité, et de nombreux travaux ont été conduits à travers la planète pour restaurer la biodiversité insulaire par des programmes d’éradication d’espèces invasives. Cependant, peu d’études scientifiques post-éradication ont été conduites notamment pour l’évaluation de la biodiversité des communautés d’Arthropodes. L’île de Bagaud, située dans l’archipel des îles d’Hyères (Var, France), est une réserve intégrale du Parc national de Port-Cros (PNPC) qui a notamment été soumise à deux perturbations majeures d’origine anthropique au cours des derniers siècles : l’invasion du Rat noir (Rattus rattus) et celle des Griffes de sorcière (Carpobrotus spp.). Ces espèces allochtones engendrent des effets particulièrement néfastes sur la flore et la faune des écosystèmes insulaires méditerranéens, notamment sur les Arthropodes. Le PNPC a ainsi lancé un programme décennal de restauration écologique qui implique l’éradication de ces deux taxons invasifs. La communauté des Arthropodes de l’île a fait l’objet d’un état initial au printemps 2011, les éradications ont été effectuées entre septembre 2011 et janvier 2013, et la première campagne d’échantillonnage post-éradication a été réalisée au printemps 2013. L’échantillonnage de la faune épigée a été réalisé au moyen de quatre transects fixes de pièges Barber répartis dans différents milieux écologiques de l’île. Cette première étude post-éradication révèle une augmentation de l’abondance des Arthropodes piégés entre 2011 (4868 individus dans 74 pièges) et 2013 (6892, n = 60). Les effectifs moyens par piège augmentent significativement dans les zones où les Carpobrotus spp. ont été arrachés, mais chutent dans la zone de maquis qui abritait une forte densité de R. rattus. La richesse spécifique reste globalement stable (220 morpho-espèces en 2011, 216 en 2013), cependant les communautés de décomposeurs explosent a contrario des populations de prédateurs. Les suivis doivent être poursuivis afin de mieux déterminer les impacts directs et indirects à long terme de ces éradications s’exerçant sur la biodiversité des communautés d’Arthropodes de l’île.Biological invasions are recognized as one of the major threats to island biodiversity conservation, and numerous studies have been conducted around the world to restore the biodiversity of islands submitted to invasive species impacts. However, few scientific post-eradication studies were piloted notably for the biodiversity assessment of Arthropod communities. Bagaud Island is an integral reserve of the Port-Cros National Park (PNPC), located in the îles d’Hyères Archipelago (Var, France). In the last centuries, it has undergone two major anthropogenic disturbances: the invasion of the Black Rat (Rattus rattus) and the Ice plants (Carpobrotus spp.), two alien taxa known for their particularly negative effects on the flora and fauna of the Mediterranean island ecosystems, including Arthropods. PNPC has launched a ten-year program of ecological restoration that involves the eradication of these two invasive taxa. The Arthropod communities of the island have been analysed in their initial state in spring 2011, eradications were conducted between September 2011 and January 2013, and the first post-eradication campaign began in spring 2013. The ground fauna was sampled using four transects of Barber traps distributed in different ecological contexts of the island. This first post-eradication study reveals an increase in the abundance of arthropods trapped between 2011 (4868 individuals in 74 traps) and 2013 (6892, n = 60). The average number of trapped Arthropods was significantly higher in areas where Carpobrotus spp. have been eradicated, but declined in the bush area that housed a high density of R. rattus. The communities of decomposers explode, in contrast to predator populations. However, the global specific richness remains stable (220 morphospecies in 2011, 216 in 2013). Scientific monitoring by the PNC must be continued to better determine the direct and indirect long-term impacts of these eradications upon the structure and the functioning of the Arthropods communities of the Bagaud Island