190 research outputs found

    Genetic variation and covariation of aphid life-history traits across unrelated host plants

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    A central paradigm of life-history theory is the existence of resource mediated trade-offs among different traits that contribute to fitness, yet observations inconsistent with this tenet are not uncommon. We previously found a clonal population of the aphid Myzus persicae to exhibit positive genetic correlations among major components of fitness, resulting in strong heritable fitness differences on a common host. This raises the question of how this genetic variation is maintained. One hypothesis states that variation for resource acquisition on different hosts may override variation for allocation, predicting strong fitness differences within hosts as a rule, but changes in fitness hierarchies across hosts due to trade-offs. Therefore, we carried out a life-table experiment with 17 clones of M. persicae, reared on three unrelated host plants: radish, common lambsquarters and black nightshade. We estimated the broad-sense heritabilities of six lifehistory traits on each host, the genetic correlations among traits within hosts, and the genetic correlations among traits on different hosts (cross-environment genetic correlations). The three plants represented radically different environments with strong effects on performance of M. persicae, yet we detected little evidence for trade-offs. Fitness components were positively correlated within hosts but also between the two more benign hosts (radish and lambsquarters), as well as between those and another host tested earlier. The comparison with the most stressful host, nightshade, was hampered by low survival. Survival on nightshade also exhibited genetic variation but was unrelated to fitness on other hosts. Acknowledging that the number of environments was necessarily limited in a quantitative genetic experiment, we suggest that the rather consistent fitness hierarchies across very different plants provided little evidence to support the idea that the clonal variation for life-history traits and their covariance structure are maintained by strong genotyperenvironment interactions with respect to hosts. Alternative explanations are discusse

    Felines Sarcoid bei einer 1-jährigen europäischen Hauskatze ausgelöst durch bovines Papillomavirus Typ 14 in der Schweiz

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    Eine einjährige Bauernhofkatze zeigte einen 5 cm grossen Knoten an der linken Nasenöffnung, der aufgrund seiner Lokalisation nur unvollständig entfernt werden konnte. Hinsichtlich der infiltrativ wachsenden, spindelförmigen Proliferation wurde histologisch ein felines Sarkoid diagnostiziert. Die aus dem Gewebe isolierte DNA konnte durch zwei PCRs als solche von bovinem Papillomavirus 14 (BPV-14) identifiziert werden. Die 194 und 549 Basenpaare (bp) langen, amplifizierten Sequenzen waren 99 bzw. 100% identisch mit einer von einem in den USA isolierten Virus, welches mit felinem Sarkoid in Zusammenhang gebracht wurde. Trotz unvollständiger Exzision, ist bis 10 Monate nach der Operation kein Rezidiv aufgetreten

    Applicability of Modified Effective-Range Theory to positron-atom and positron-molecule scattering

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    We analyze low-energy scattering of positrons on Ar atoms and N2 molecules using Modified Effective-Range Theory (MERT) developped by O'Malley, Spruch and Rosenberg [Journal of Math. Phys. 2, 491 (1961)]. We use formulation of MERT based on exact solutions of Schroedinger equation with polarization potential rather than low-energy expansions of phase shifts into momentum series. We show that MERT describes well experimental data, provided that effective-range expansion is performed both for s- and p-wave scattering, which dominate in the considered regime of positron energies (0.4 - 2 eV). We estimate the values of the s-wave scattering lenght and the effective range for e+ - Ar and e+ - N2 collisions.Comment: RevTeX, 4 pages, 2 figure

    Effects of S-wave thresholds

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    The opening of a new S-wave threshold is frequently accompanied by an abrupt dip in the magnitude of an amplitude for an already-open channel. One familiar example is the behavior of the I=0 S-wave ππ\pi \pi scattering amplitude at KKˉK \bar K threshold. Numerous other examples of this phenomenon in recent data are noted, and a unified description of the underlying dynamics is sought.Comment: 17 pages, 2 figures. Two additional references; typographic correction. To be published in Phys. Rev.

    A randomized controlled trial comparing Circle of Security Intervention and treatment as usual as interventions to increase attachment security in infants of mentally ill mothers: Study Protocol

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    Psychopathology in women after childbirth represents a significant risk factor for parenting and infant mental health. Regarding child development, these infants are at increased risk for developing unfavorable attachment strategies to their mothers and for subsequent behavioral, emotional and cognitive impairments throughout childhood. To date, the specific efficacy of an early attachment-based parenting group intervention under standard clinical outpatient conditions, and the moderators and mediators that promote attachment security in infants of mentally ill mothers, have been poorly evaluated

    Parental Reflective Functioning Affects Sensitivity to Distress in Mothers with Postpartum Depression

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    Parental reflective functioning (PRF) refers to the capacity of caregivers to reflect upon their children’s internal mental states and intentions, which is seen as crucial for parental sensitivity, defined as the adequate behavioral response to an infant’s signals. In this study, the effect of maternal PRF on sensitivity during the mother–infant interaction was examined in a clinical sample of 50 mothers who were experiencing postpartum depression and their infants aged three to 10 months. Mother and infant were exposed to emotional distress using the still-face procedure. It was hypothesized that low levels of PRF are associated with a decrease in maternal sensitivity in response to distress. Maternal PRF was assessed using the parental reflective functioning questionnaire (PRF). The subscales measured interest and curiosity in mental states, certainty about mental states (i.e., the recognition of the opacity of mental states), and pre-mentalizing modes (i.e., non-mentalizing modes), whereas sensitivity was evaluated using the maternal behavior Q-sort (Mini-MBQS-V). The results revealed a significant overall decrease in maternal sensitivity. As expected, the higher the scores on the pre-mentalizing modes, which indicated low levels of mentalizing through the mothers’ repudiation or defense against it, the greater the decreases in sensitivity. No effects with respect to the interest and curiosity in mental states or the certainty about mental states were found. Our findings determined that the pre-mentalizing modes are predictive of sensitivity to distress in mothers with postpartum depression

    The diagnosis of rupture of fetal membranes (ROM): a meta-analysis

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    Aim: The aim of this study was to compare the performance of tests based on the detection of insulin-like growth factor binding protein 1 (IGFBP-1) and placental α-microglobulin-1 (PAMG-1) in diagnosing rupture of fetal membranes (ROM) across different patient populations. Methods: A meta-analysis was conducted on prospective observational or cohort studies investigating ROM tests based on the detection of IGFBP-1 and PAMG-1 meeting the following criteria: (1) performance metrics calculated by comparing results to an adequate reference method; (2) sensitivity thresholds of the investigated tests matching those of the currently available tests; (3) study population, as a minimum, included patients between 25 and 37 weeks of gestation. Sensitivities, specificities, and diagnostic odds ratios were calculated. Results: Across all patient populations, the analyzed performance measures of the PAMG-1 test were significantly superior compared with those of the IGFBP-1 test. Of particular clinical relevance, PAMG-1 outperformed IGFBP-1 in the equivocal group, which comprised patients with uncertain rupture of membranes (sensitivity, 96.0% vs. 73.9%; specificity, 98.9% vs. 77.8%; PAMG-1 vs. IGFBP-1 tests, respectively). Conclusions: Compared with its performance in women with known membrane status, the accuracy of the IGFBP-1 test decreases significantly when used on patients whose membrane status is unknown. In this latter clinically relevant population, the PAMG-1 test has higher accuracy than the IGFBP-1 tes

    Anti-Neoplastic Activity of Two Flavone Isomers Derived from Gnaphalium elegans and Achyrocline bogotensis

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    Over 4000 flavonoids have been identified so far and among these, many are known to have antitumor activities. The basis of the relationships between chemical structures, type and position of substituent groups and the effects these compounds exert specifically on cancer cells are not completely elucidated. Here we report the differential cytotoxic effects of two flavone isomers on human cancer cells from breast (MCF7, SK-BR-3), colon (Caco-2, HCT116), pancreas (MIA PaCa, Panc 28), and prostate (PC3, LNCaP) that vary in differentiation status and tumorigenic potential. These flavones are derived from plants of the family Asteraceae, genera Gnaphalium and Achyrocline reputed to have anti-cancer properties. Our studies indicate that 5,7-dihydroxy-3,6,8-trimethoxy-2-phenyl-4H-chromen-4-one (5,7-dihydroxy-3,6,8-trimethoxy flavone) displays potent activity against more differentiated carcinomas of the colon (Caco-2), and pancreas (Panc28), whereas 3,5-dihydroxy-6,7,8-trimethoxy-2-phenyl-4H-chromen-4-one (3,5-dihydroxy-6,7,8-trimethoxy flavone) cytototoxic action is observed on poorly differentiated carcinomas of the colon (HCT116), pancreas (Mia PaCa), and breast (SK-BR3). Both flavones induced cell death (\u3e50%) as proven by MTT cell viability assay in these cancer cell lines, all of which are regarded as highly tumorigenic. At the concentrations studied (5–80 µM), neither flavone demonstrated activity against the less tumorigenic cell lines, breast cancer MCF-7 cells, androgen-responsive LNCaP human prostate cancer line, and androgen-unresponsive PC3 prostate cancer cells. 5,7-dihydroxy-3,6,8-trimethoxy-2-phenyl-4H-chromen-4-one (5,7-dihydroxy-3,6,8-trimethoxy flavone) displays activity against more differentiated carcinomas of the colon and pancreas, but minimal cytotoxicity on poorly differentiated carcinomas of these organs. On the contrary, 3,5-dihydroxy-6,7,8-trimethoxy-2-phenyl-4H-chromen-4-one (3,5-dihydroxy-6,7,8-trimethoxy flavone) is highly cytotoxic to poorly differentiated carcinomas of the colon, pancreas, and breast with minimal activity against more differentiated carcinomas of the same organs. These differential effects suggest activation of distinct apoptotic pathways. In conclusion, the specific chemical properties of these two flavone isomers dictate mechanistic properties which may be relevant when evaluating biological responses to flavones
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