36 research outputs found

    Positive Interactions between Desert Granivores: Localized Facilitation of Harvester Ants by Kangaroo Rats

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    Facilitation, when one species enhances the environment or performance of another species, can be highly localized in space. While facilitation in plant communities has been intensely studied, the role of facilitation in shaping animal communities is less well understood. In the Chihuahuan Desert, both kangaroo rats and harvester ants depend on the abundant seeds of annual plants. Kangaroo rats, however, are hypothesized to facilitate harvester ants through soil disturbance and selective seed predation rather than competing with them. I used a spatially explicit approach to examine whether a positive or negative interaction exists between banner-tailed kangaroo rat (Dipodomys spectabilis) mounds and rough harvester ant (Pogonomyrmex rugosus) colonies. The presence of a scale-dependent interaction between mounds and colonies was tested by comparing fitted spatial point process models with and without interspecific effects. Also, the effect of proximity to a mound on colony mortality and spatial patterns of surviving colonies was examined. The spatial pattern of kangaroo rat mounds and harvester ant colonies was consistent with a positive interspecific interaction at small scales (<10 m). Mortality risk of vulnerable, recently founded harvester ant colonies was lower when located close to a kangaroo rat mound and proximity to a mound partly predicted the spatial pattern of surviving colonies. My findings support localized facilitation of harvester ants by kangaroo rats, likely mediated through ecosystem engineering and foraging effects on plant cover and composition. The scale-dependent effect of kangaroo rats on abiotic and biotic factors appears to result in greater founding and survivorship of young colonies near mounds. These results suggest that soil disturbance and foraging by rodents can have subtle impacts on the distribution and demography of other species

    Wine and other alcohol consumption and risk of ovarian cancer in the California Teachers Study cohort

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    OBJECTIVE: Whether alcohol consumption influences ovarian cancer risk is unclear. Therefore, we investigated the association between alcohol intake at various ages and risk of ovarian cancer. METHODS: Among 90,371 eligible members of the California Teachers Study cohort who completed a baseline alcohol assessment in 1995–1996, 253 women were diagnosed with epithelial ovarian cancer by the end of 2003. Multivariate Cox proportional hazards regression analysis was performed to estimate relative risks (RRs) and 95% confidence intervals (CIs). RESULTS: Consumption of total alcohol, beer, or liquor in the year prior to baseline, at ages 30–35 years, or at ages 18–22 years was not associated with risk of ovarian cancer. Consumption of at least one glass per day of wine, compared to no wine, in the year before baseline was associated with increased risk of developing ovarian cancer: RR = 1.57 (95% CI 1.11–2.22), P(trend) = 0.01. The association with wine intake at baseline was particularly strong among peri-/post-menopausal women who used estrogen-only hormone therapy and women of high socioeconomic status. CONCLUSIONS: Alcohol intake does not appear to affect ovarian cancer risk. Constituents of wine other than alcohol or, more likely, unmeasured determinants of wine drinking were associated with increased risk of ovarian cancer

    Crk and CrkL adaptor proteins: networks for physiological and pathological signaling

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    The Crk adaptor proteins (Crk and CrkL) constitute an integral part of a network of essential signal transduction pathways in humans and other organisms that act as major convergence points in tyrosine kinase signaling. Crk proteins integrate signals from a wide variety of sources, including growth factors, extracellular matrix molecules, bacterial pathogens, and apoptotic cells. Mounting evidence indicates that dysregulation of Crk proteins is associated with human diseases, including cancer and susceptibility to pathogen infections. Recent structural work has identified new and unusual insights into the regulation of Crk proteins, providing a rationale for how Crk can sense diverse signals and produce a myriad of biological responses

    Candidiasis, Bacterial Vaginosis, Trichomoniasis and Other Vaginal Conditions Affecting the Vulva

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    A Systematic Review of the Literature on Parenting of Young Children with Visual Impairments and the Adaptions for Video-Feedback Intervention to Promote Positive Parenting (VIPP)

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    Secure parent-child attachment may help children to overcome the challenges of growing up with a visual or visual-and-intellectual impairment. A large literature exists that provides a blueprint for interventions that promote parental sensitivity and secure attachment. The Video-feedback Intervention to promote Positive Parenting (VIPP) is based on that blueprint. While it has been adapted to several specific at risk populations, children with visual impairment may require additional adjustments. This study aimed to identify the themes that should be addressed in adapting VIPP and similar interventions. A Delphi-consultation was conducted with 13 professionals in the field of visual impairment to select the themes for relationship-focused intervention. These themes informed a systematic literature search. Interaction, intersubjectivity, joint attention, exploration, play and specific behavior were the themes mentioned in the Delphi-group. Paired with visual impairment or vision disorders, infants or young children (and their parents) the search yielded 74 articles, making the six themes for intervention adaptation more specific and concrete. The rich literature on six visual impairment specific themes was dominated by the themes interaction, intersubjectivity, and joint attention. These themes need to be addressed in adapting intervention programs developed for other populations, such as VIPP which currently focuses on higher order constructs of sensitivity and attachment

    Plant growth promoting rhizobia: challenges and opportunities

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    Mapping Chicken Genes Using Preferential Amplification of Specific Alleles

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    The product of the cellular crk gene consists primarily of SH2 and SH3 regions.

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    We have cloned and sequenced a complementary DNA encoding the cellular homologue of the transforming oncogene v-crk of avian sarcoma virus CT10. This complementary DNA contains an open reading frame of 915 base pairs that encodes a polypeptide of 305 amino acids. The first 205 amino acids of this c-Crk protein were identical to those of the CT10 encoded v-Crk protein, with the exception of 5 amino acids. Like v-Crk, this portion of c-Crk contained one each of the Src homology domains SH2, SH2', and SH3. The 100 carboxy-terminal amino acids of c-Crk protein, which are not coded for in the CT10 viral genome, contain another SH3 region. We found limited sequence homology between c-crk and the avian retrovirus genome, which explains recombination events in the transduction of this protooncogene. Using a polyclonal antiserum made against bacterially expressed v-crk, we identified a 35-kilodalton protein in normal chicken embryo fibroblasts and in all embryonic chicken tissues examined. This 35-kilodalton protein was indistinguishable from a polypeptide made by in vitro translation of c-crk complementary DNA
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