7,228 research outputs found

    FIELD TESTS FOR MEDICAGO RESISTANCE AGAINST THE POTATO LEAFHOPPER (HOMOPTERA: CICADELLIDAE)

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    A collection of 70 Medicago introductions were field tested for resistance against potato leafhopper, Empoasca fabae (Harris), damage. All M. sativa L. ssp. sativa and most ssp. mixtures were susceptible. All ssp. falcata (L.) Arcangeli, one ssp. mixture sativa and caerulea (Lessing ex Ledebour) Schmalhausen, ssp. × varia (Martyn) Arcangeli and M. pironae Vis were resistant receiving one-half or less damage than the standard cultivars during four seasons of testing. Resistant introductions were slower in regrowth, attained less height, had smaller leaflets, thinner, tougher stems, and more prostrate growth than standard cultivars. Results suggest most observed resistance is due to avoidance of tough stems for ovipositio

    Carrier density dependence of 1/f noise in graphene explained as a result of the interplay between band-structure and inhomogeneities

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    http://www.gianlucafiori.org/articles/jstat_noise.pdf We present a model for 1/f noise in graphene based on an analysis of the effect of charge trapping and detrapping events on the fluctuations of the number of charge carriers. Inclusion of a Gaussian distribution of fluctuations of the electrostatic potential enables us to reproduce all the various experimentally observed behaviors of the flicker noise power spectral density as a function of carrier density, both for monolayer and bilayer graphene. The key feature of a flicker noise minimum at the Dirac point that appears in bilayer graphene and sometimes also in monolayer graphene is explained in terms of the disappearance, when the number of electrons equals that of holes, of the carrier number fluctuations induced by trapping events. Such a disappearance is analyzed with two different approaches, in order to gain a better understanding of the physical origin of the effect, and to make some considerations about possible analogous phenomena in other semiconductors

    High count rate {\gamma}-ray spectroscopy with LaBr3:Ce scintillation detectors

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    The applicability of LaBr3:Ce detectors for high count rate {\gamma}-ray spectroscopy is investigated. A 3"x3" LaBr3:Ce detector is used in a test setup with radioactive sources to study the dependence of energy resolution and photo peak efficiency on the overall count rate in the detector. Digitized traces were recorded using a 500 MHz FADC and analysed with digital signal processing methods. In addition to standard techniques a pile-up correction method is applied to the data in order to further improve the high-rate capabilities and to reduce the losses in efficiency due to signal pile-up. It is shown, that {\gamma}-ray spectroscopy can be performed with high resolution at count rates even above 1 MHz and that the performance can be enhanced in the region between 500 kHz and 10 MHz by using pile-up correction techniques

    Pharmacokinetics of orally administered tetrahydrobiopterin in patients with phenylalanine hydroxylase deficiency

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    Summary: The oral loading test with tetrahydrobiopterin (BH4) is used to discriminate between variants of hyperphenylalaninaemia and to detect BH4-responsive patients. The outcome of the loading test depends on the genotype, dosage of BH4, and BH4 pharmacokinetics. A total of 71 patients with hyperphenylalaninaemia (mild to classic) were challenged with BH4 (20 mg/kg) according to different protocols (1 × 20 mg or 2 × 20 mg) and blood BH4 concentrations were measured in dried blood spots at different time points (T0, T2, T4, T8, T12, T24, T32 and T48 h). Maximal BH4 concentrations (median 22.69 nmol/g Hb) were measured 4 h after BH4 administration in 63 out of 71 patients. Eight patients presented with maximal BH4 concentrations ∼44% higher at 8 h than at 4 h. After 24 h, BH4 blood concentrations dropped to 11% of maximal values. This profile was similar using different protocols. The following pharmacokinetic parameters were calculated for BH4 in blood: t max = 4 h, AUC (T0−32) = 370 nmol × h/g Hb, and t 1/2 for absorption (1.1 h), distribution (2.5 h), and elimination (46.0 h) phases. Maximal BH4 blood concentrations were not significantly lower in non-responders and there was no correlation between blood concentrations and responsiveness. Of mild PKU patients, 97% responded to BH4 administration, while one was found to be a non-responder. Only 10/19 patients (53%) with Phe concentrations of 600-1200 μmol/L responded to BH4 administration, and of the patients with the severe classical phenotype (blood Phe > 1200 μmol/L) only 4 out of 17 patient responded. An additional 36 patients with mild hyperphenylalaninaemia (HPA) who underwent the combined loading test with Phe+BH4 were all responders. Slow responders and non-responders were found in all groups of HP

    Relationship Talk With Partners and Friends During Emerging Adulthood: The Role of Relationship Satisfaction

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    Research indicates that discussing one’s romantic relationship with one’s partner benefits individual well-being and reduces uncertainty about the future of the relationship. Implications of relationship talk with friends remain less clear, though talking with friends may actually increase uncertainty about the relationship (e.g., by making one’s partner jealous of these friends), particularly for emerging adults. Relationship talk with friends may be especially likely to promote relational uncertainty for couples who are already unsatisfied in their relationships. In this study, we explored whether relationship talk with one’s partner and one’s friends would each be uniquely associated with depressive symptoms and uncertainty about the relationship, specifically in the form of perceived partner jealousy of one’s friends and whether these associations would be moderated by relationship satisfaction. Results from a series of path models using data from 202 romantically involved emerging adults in the United States revealed that associations between relationship talk and outcomes were indeed moderated by relationship satisfaction. For example, only in unsatisfied relationships was relationship talk with friends positively associated with a partner\u27s jealousy and negatively associated with depressive symptoms. This research expands our understanding of relationship talk by differentiating between talk with partners versus friends, while considering the contextual role of relationship satisfaction
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