1,430 research outputs found

    Wheat classification exercise, using 11 June 1973, ERTS MSS data for Fayette County, Illinois (for CITARS task)

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    The prime emphasis was on classification of pixels in field centers, away from boundary effects. Results were encouraging in both training and test field centers for wheat and other major types of vegetation present. However, the location of fields was found to be a serious problem and it was even more difficult to select field-center pixels for fields of sizes less than 20 acres (or even larger, depending upon field shape) for use in the field-center analysis. The majority of fields in the segment are less than 20 acres in size. ERTS-1 data were received on 12 September 1973. Ground truth information and aerial photography were received on 9 and 15 September. The data were analyzed and processed digitally using the ERIM multispectral software system

    5-Methyl-tetrahydrofolate in prevention of recurrent preeclampsia

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    Objective: To evaluate the efficacy of 5-methyl-tetrahydrofolate (5-MTHF) supplementation in prevention of recurrent preeclampsia.Methods: Retrospective cohort of women who received daily oral 5-MTHF 15 mg supplementation as prophylactic treatment since first trimester for recurrent preeclampsia were compared with women who did not. All asymptomatic singleton gestations with prior preeclampsia (in the previous pregnancy) were included. Women with chronic hypertension were excluded. The primary outcome was the incidence of preeclampsia.Results: Three hundred and three singleton gestation met the inclusion criteria: 157 received 5-MTHF, while 146 did not (control group). Women who received 5-MTHF had a significantly lower incidence of recurrent overall preeclampsia (21.7% versus 39.7%; odds ratio (OR) 0.57, 95% confidence interval (CI) 0.25, 0.69), severe preeclampsia (3.2% versus 8.9%; OR 0.44, 95% CI 0.12-0.97) and early-onset preeclampsia (1.9% versus 7.5%; OR 0.34, 95% CI 0.07-0.87) compared to control. The intervention group delivered about 10 d after the control and had higher birth weight.Conclusion: This retrospective study showed that women with prior preeclampsia who received daily oral 5-MTHF 15 mg supplementation had a significantly lower incidence of overall preeclampsia, severe preeclampsia and early-onset preeclampsia. Randomized controlled trials are needed to confirm our findings

    Field emission properties of as-grown multiwalled carbon nanotube films

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    Multiwalled carbon nanotubes have been produced by ethylene catalytic chemical vapor deposition and used to fabricate thick and dense freestanding films ("buckypapers") by membrane filtering. Field emission properties of buckypapers have been locally studied by means of high vacuum atomic force microscopy with a standard metallic cantilever used as anode to collect electrons emitted from the sample. Buckypapers showed an interesting linear dependence in the Fowler-Nordheim plots demonstrating their suitability as emitters. By precisely tuning the tip-sample distance in the submicron region we found out that the field enhancement factor is not affected by distance variations up to 2um. Finally, the study of current stability showed that the field emission current with intensity of about 3,3*10-5A remains remarkably stable (within 5% fluctuations) for several hours.Comment: 18 pages, 5 figure

    Therapeutic sequences in patients with grade 1−2 neuroendocrine tumors (NET): an observational multicenter study from the ELIOS group

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    Purpose: Many different treatments are suggested by guidelines to treat grade 1−2 (G1−G2) neuroendocrine tumors (NET). However, a precise therapeutic algorithm has not yet been established. This study aims at identifying and comparing the main therapeutic sequences in G1−G2 NET. Methods: A retrospective observational Italian multicenter study was designed to collect data on therapeutic sequences in NET. Median progression-free survival (PFS) was compared between therapeutic sequences, as well as the number and grade of side effects and the rate of dose reduction/treatment discontinuation. Results: Among 1182 patients with neuroendocrine neoplasia included in the ELIOS database, 131 G1–G2 gastroenteropancreatic, lung and unknown primary NET, unresectable or persistent/relapsing after surgery, treated with ≥2 systemic treatments, were included. Four main therapeutic sequences were identified in 99 patients: (A) somatostatin analogs (SSA) standard dose to SSA high dose (n = 36), (B) SSA to everolimus (n = 31), (C) SSA to chemotherapy (n = 17), (D) SSA to peptide receptor radionuclide therapy (PRRT) (n = 15). Median PFS of the second-line treatment was not reached in sequence A, 33 months in sequence B, 20 months in sequence C, 30 months in sequence D (p = 0.16). Both total number and severity of side effects were significantly higher in sequences B and C than A and D (p = 0.04), as well as the rate of dose reduction/discontinuation (p = 0.03). Conclusions: SSA followed by SSA high dose, everolimus, chemotherapy or PRRT represent the main therapeutic sequences in G1−G2 NET. Median PFS was not significantly different between sequences. However, the sequences with SSA high dose or PRRT seem to be better tolerated than sequences with everolimus or chemotherapy

    Imaging performance of phase-contrast breast computed tomography with synchrotron radiation and a CdTe photon-counting detector

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    Purpose: Within the SYRMA-CT collaboration based at the ELETTRA synchrotron radiation (SR) facility (Trieste, Italy) the authors investigated the imaging performance of the phase-contrast computed tomography (CT) system dedicated to monochromatic in vivo 3D imaging of the female breast, for breast cancer diagnosis. Methods: Test objects were imaged at 38 keV using monochromatic SR and a high-resolution CdTe photon-counting detector. Signal and noise performance were evaluated using modulation transfer function (MTF) and Noise Power Spectrum (NPS). Phase-contrast CT images as well as images obtained after the application of a phase-retrieval algorithm were evaluated. The contrast to noise ratio (CNR) and the capability of detecting test microcalcification clusters and soft masses were explored. Results: For a voxel size of (60 \u3bcm)3, phase-contrast images showed higher spatial resolution (6.7 mm-1 at 10% MTF) than corresponding phase retrieval images (2.5 mm-1). Phase retrieval produced a reduction of the noise level as well as an increase of the CNR by more than one order of magnitude, compared to raw phase-contrast images. CaCO3 microcalcifications with a diameter down to 130 \u3bcm were detected both in phase-contrast and in phase retrieval images of the test object. Conclusions: The investigation on test objects indicates that breast CT with a monochromatic SR source is technically feasible in terms of spatial resolution, image noise and contrast, for in vivo 3D imaging with a dose comparable to that of two-view mammography. Phase-retrieved images showed the best performance in the trade-off between spatial resolution and image noise

    Quenched BKB_K-parameter with the Wilson and Clover actions at β=6.0\beta = 6.0

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    We present results for the Kaon BB parameter from a sample of 200200 configurations using the Wilson action and 460460 configurations using the Clover action, on a 183×6418^3 \times 64 lattice at β=6.0\beta=6.0. A slight improvement of the chiral behaviour of BKB_K is observed due to the Clover action. We have also compared the results for BKB_K obtained from two different procedures for the boosting of the coupling constant gg. We observe a strong dependence of BKB_K on the prescription adopted for gg in the Wilson case, contrary to the results of the Clover case which are almost unaffected by the choice of gg. Combining some recently obtained non perturbative estimates for the renormalisation constants with our Clover matrix element, we observe a significant improvement in the chiral behaviour of BKB_K.Comment: 3 pages, Latex, Postscript file with figures available at ftp://hpteo.roma1.infn.it/pub/preprints/lat94/donini ; to appear in Lattice '94, Nucl. Phys. (Proc.Suppl.

    Histological chorioamnionitis and risk of pulmonary complications in preterm births: a systematic review and Meta-analysis

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    Histological chorioamnionitis is associated with significant adverse maternal, perinatal and long-term outcome. We performed a meta-analysis of 30 observational studies in order to clarify the association between Histological chorioamnionitis and pulmonary complications, like respiratory distress syndrome and Bronchopulmonary Dysplasia. Unadjusted data extracted from all studies showed that Histological chorioamnionitis has no effect on development of RDS (RR 0.93, 95% CI 1.08-1.67), while it increased the risk of Bronchopulmonary Dysplasia (RR 1.75, 95% CI 1.37-2.23). However, when we restricted the analysis to the studies that adjust for Gestational Age, in order to exclude the influence of prematurity, we found that HCA reduced the risk of respiratory distress syndrome (RR 0.57, CI 95% 0.35-0.93) and it did not affect the development of Bronchopulmonary Dysplasia (RR 0.99, CI 0.76-1.3). Our results confirmed a possible role of prenatal inflammation on lung maturation. However, further prospective studies with a selected population are needed, in order to clarify the role of Histological chorioamnionitis in neonatal pulmonary complications

    Superconducting properties of Nb thin films deposited on porous silicon templates

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    Porous silicon, obtained by electrochemical etching, has been used as a substrate for the growth of nanoperforated Nb thin films. The films, deposited by UHV magnetron sputtering on the porous Si substrates, inherited their structure made of holes of 5 or 10 nm diameter and of 10 to 40 nm spacing, which provide an artificial pinning structure. The superconducting properties were investigated by transport measurements performed in the presence of magnetic field for different film thickness and substrates with different interpore spacing. Perpendicular upper critical fields measurements present peculiar features such as a change in the H_c2(T) curvature and oscillations in the field dependence of the superconducting resistive transition width at H=1 Tesla. This field value is much higher than typical matching fields in perforated superconductors, as a consequence of the small interpore distance.Comment: accepted for publication on Journal of Applied Physic

    Decay Constants of Heavy-Light Mesons

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    The decay constants of the heavy-light pseudoscalar mesons are studied in a high statistics run using the Wilson action at β=6.0\beta=6.0 and β=6.2\beta=6.2, and the clover action at β=6.0\beta=6.0. The systematics of O(a)O(a) discretisation errors are discussed. Our best estimates of the decay constants are: fDf_D = 218(9) MeV, fD/fDsf_D/f_{Ds} = 1.11(1) and we obtain preliminary values for fBf_B.Comment: at the Dallas Lattice Conference, October 1993. 3 pages in a single postscript file, uuencoded form. Rome Preprint 93/98

    Between Andes and Amazon: The genetic profile of the Arawak-speaking Yanesha

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    The Yanesha are a Peruvian population who inhabit an environment transitional between the Andes and Amazonia. They present cultural traits characteristic of both regions, including in the language they speak: Yanesha belongs to the Arawak language family (which very likely originated in the Amazon/Orinoco lowlands), but has been strongly influenced by Quechua, the most widespread language family of the Andes. Given their location and cultural make-up, the Yanesha make for an ideal case study for investigating language and population dynamics across the Andes-Amazonia divide. In this study, we analyze data from high and mid-altitude Yanesha villages, both Y chromosome (17 STRs and 16 SNPs diagnostic for assigning haplogroups) and mtDNA data (control region sequences and 3 SNPs and one INDEL diagnostic for assigning haplogroups). We uncover sex-biased genetic trends that probably arose in different stages: first, a male-biased gene flow from Andean regions, genetically consistent with highland Quechua-speakers and probably dating back to Inca expansion; and second, traces of European contact consistent with Y chromosome lineages from Italy and Tyrol, in line with historically documented migrations. Most research in the history, archaeology and linguistics of South America has long been characterized by perceptions of a sharp divide between the Andes and Amazonia; our results serve as a clear case-study confirming demographic flows across that \u2018divide\u2019
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