15,984 research outputs found

    Solvent Deactivation of Mimosa Webworm Larval Webbing (Lepidoptera: Plutellidae)

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    Untreated larval webbing of the mimosa webworm, Homadaula anisocentra stimulated oviposition. Six-week-old webbing was as active as two-day-old webbing. Stimulatory activity of webbing was lost after rinsing with highly polar solvents, but not after rinsing with nonpolar solvents. Addition of the polar solvent rinses did not induce activity in other substrates nor restore activity to rinsed webbing. No differences in structure were found in a scanning electron microscope examination of unrinsed webbing and webbing rinsed with solvents of varying polarity

    KPD1930+2752 - a candidate Type Ia supernova progenitor

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    We present spectra of the pulsating sdB star KPD1930+2752 which confirm that this star is a binary. The radial velocities measured from the H-alpha and HeI6678 spectral lines vary sinusoidally with the same period (2h 17m) as the ellipsoidal variability seen by Billeres et al. (2000). The amplitude of the orbital motion (349.3+-2.7 km/s) combined with the canonical mass for sdB stars (0.5 solar masses) implies a total mass for the binary of 1.47+-0.01 solar masses The unseen companion star is almost certainly a white dwarf star. The binary will merge within about 200 million years due to gravitational wave radiation. The accretion of helium and other elements heavier than hydrogen onto the white dwarf which then exceeds the Chandrasekhar mass (1.4 solar masses) is a viable model for the cause of Type Ia supernovae. KPD1930+2752 is the first star to be discovered which is a good candidate for the progenitor of a Type Ia supernova of this type which will merge on an astrophysically interesting timescale.Comment: Accepted for publication in MNRAS. 4 pages, 2 figures. Added Institutio

    La evoluciĂłn de las economĂ­as en el transcurso del tiempo

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    Nuevos enfoques en la historia económica de España y de América Latina. Homenaje a Robert W. Fogel y Douglas C. North, Premios Nobel de Economía 1993Editada en la Universidad Carlos IIIPublicad

    Investigation of Noise Field and Velocity Profiles of an Afterburning Engine

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    Sound pressure levels, frequency spectrum, and jet velocity profiles are presented for an engine-afterburner combination at various values of afterburner fuel - air ratio. At the high fuel-air ratios, severe low-frequency resonance was encountered which represented more than half the total energy in the sound spectrum. At similar thrust conditions, lower sound pressure levels were obtained from a current fighter air craft with a different afterburner configuration. The lower sound pressure levels are attributed to resonance-free afterburner operation and thereby indicate the importance of acoustic considerations in afterburner design

    CNONa and 12C/13C in giants of 10 open clusters

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    Evolved low-mass stars of a wide range of metallicity bear signatures of a non-standard mixing event in their surface abundances of Li, C, and N, and in their 12C/13C ratio. A Na overabundance has also been reported in some giants of open clusters but remains controversial. The cause of the extra-mixing has been attributed to thermohaline convection that should take place after the RGB bump for low-mass stars and on the early-AGB for more massive objects. To track the occurrence of this process over a wide mass range, we derive in a homogeneous way the abundances of C, N, O, and Na, as well as the 12C/13C ratio in a sample of 31 giants of 10 open clusters with turn-off masses from 1.7 to 3.1 Msun. A group of first ascent red giants with M/Msun \leq 2.5 exhibits lower [N/C] ratios than those measured in clump giants of the same mass range, suggesting an additional increase in the [N/C] ratio after the first dredge-up. The sodium abundances corrected from NLTE are found to be about solar. [Na/Fe] shows a slight increase of 0.10 dex as a function of stellar mass in the 1.8 to 3.2 Msun range covered by our sample, in agreement with standard first dredge-up predictions. Our results do not support previous claims of sodium overabundances as high as +0.60 dex. An anti-correlation between 12C/13C and turn-off mass is identified and interpreted as being caused by a post-bump thermohaline mixing. Moreover, we find low 12C/13C ratios in a few intermediate-mass early-AGB stars, confirming that an extra-mixing process also operates in stars that do not experienced the RGB bump. In this case, the extra-mixing possibly acts on the early-AGB, in agreement with theoretical expectations for thermohaline mixing. [abridged]Comment: A&A accepted, revised versio

    A Conceptual Framework for Interpreting Recorded Human History

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    Neither economics nor political science can explain the process of modern social development. The fact that developed societies always have developed economies and developed polities suggests that the connection between economics and politics must be a fundamental part of the development process. This paper develops an integrated theory of economics and politics. We show how, beginning 10,000 years ago, limited access social orders developed that were able to control violence, provide order, and allow greater production through specialization and exchange. Limited access orders provide order by using the political system to limit economic entry to create rents, and then using the rents to stabilize the political system and limit violence. We call this type of political economy arrangement a natural state. It appears to be the natural way that human societies are organized, even in most of the contemporary world. In contrast, a handful of developed societies have developed open access social orders. In these societies, open access and entry into economic and political organizations sustains economic and political competition. Social order is sustained by competition rather than rent-creation. The key to understanding modern social development is understanding the transition from limited to open access social orders, which only a handful of countries have managed since WWII.

    Assessing somatization in urologic chronic pelvic pain syndrome

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    BACKGROUND: This study examined the prevalence of somatization disorder in Urological Chronic Pelvic Pain Syndrome (UCPPS) and the utility of two self-report symptom screening tools for assessment of somatization in patients with UCPPS. METHODS: The study sample included 65 patients with UCPPS who enrolled in the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Study at Washington University. Patients completed the PolySymptomatic PolySyndromic Questionnaire (PSPS-Q) (n = 64) and the Patient Health Questionnaire-15 Somatic Symptom Severity Scale (PHQ-15) (n = 50). Review of patient medical records found that only 47% (n = 30) contained sufficient documentation to assess Perley-Guze criteria for somatization disorder. RESULTS: Few (only 6.5%) of the UCPPS sample met Perley-Guze criteria for definite somatization disorder. Perley-Guze somatization disorder was predicted by definite PSPS-Q somatization with at least 75% sensitivity and specificity. Perley-Guze somatization disorder was predicted by severe (\u3e 15) PHQ-15 threshold that had \u3e 90% sensitivity and specificity but was met by only 16% of patients. The moderate (\u3e 10) PHQ-15 threshold had higher sensitivity (100%) but lower specificity (52%) and was met by 52% of the sample. CONCLUSIONS: The PHQ-15 is brief, but it measures symptoms constituting only one dimension of somatization. The PSPS-Q uniquely captures two conceptual dimensions inherent in the definition of somatization disorder, both number of symptoms and symptom distribution across multiple organ systems, with relevance for UCPPS as a syndrome that is not just a collection of urological symptoms but a broader syndrome with symptoms extending beyond the urological system
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