5,924 research outputs found

    Hybrid receiver study

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    The results are presented of a 4 month study to design a hybrid analog/digital receiver for outer planet mission probe communication links. The scope of this study includes functional design of the receiver; comparisons between analog and digital processing; hardware tradeoffs for key components including frequency generators, A/D converters, and digital processors; development and simulation of the processing algorithms for acquisition, tracking, and demodulation; and detailed design of the receiver in order to determine its size, weight, power, reliability, and radiation hardness. In addition, an evaluation was made of the receiver's capabilities to perform accurate measurement of signal strength and frequency for radio science missions

    TGF beta 1 attenuates expression of prolactin and IGFBP-1 in decidualized endometrial stromal cells by both SMAD-dependent and SMAD-independent pathways

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    Background: Decidualization (differentiation) of the endometrial stromal cells during the secretory phase of the menstrual cycle is essential for successful implantation. Transforming Growth Factor beta 1 (TGF beta 1) canonically propagates its actions via SMAD signalling. A role for TGF beta 1 in decidualization remains to be established and published data concerning effects of TGF beta 1 on markers of endometrial decidualization are inconsistent. Methodology/Principal Findings: Non-pregnant endometrial stromal cells (ESC) and first trimester decidual stromal cells (DSC) were cultured in the presence or absence of a decidualizing stimulus. Incubation of ESCs with TGF beta 1 (10 ng/ml) down-regulated the expression of transcripts encoding the decidual marker proteins prolactin (PRL), insulin-like growth factor binding protein-1 (IGFBP-1) and tissue factor (TF). TGF beta 1 also inhibited secretion of PRL and IGFBP-1 proteins by ESCs and surprisingly this response preceded down-regulation of their mRNAs. In contrast, DSCs were more refractory to the actions of TGF beta 1, characterized by blunted and delayed down-regulation of PRL, IGFBP-1, and TF transcripts, which was not associated with a significant reduction in secretion of PRL or IGFBP-1 proteins. Addition of an antibody directed against TGF beta 1 increased expression of IGFBP-1 mRNA in decidualised cells. Knockdown of SMAD 4 using siRNAs abrogated the effect of TGF beta 1 on expression of PRL in ESCs but did not fully restore expression of IGFBP-1 mRNA and protein. Conclusions/Significance: TGF beta 1 inhibits the expression and secretion of decidual marker proteins. The impact of TGF beta 1 on PRL is SMAD-dependent but the impact on IGFBP1 is via an alternative mechanism. In early pregnancy, resistance of DSC to the impact of TGF beta 1 may be important to ensure tissue homeostasis

    The Power Spectrum of the PSC Redshift Survey

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    We measure the redshift-space power spectrum P(k) for the recently completed IRAS Point Source Catalogue (PSC) redshift survey, which contains 14500 galaxies over 84% of the sky with 60 micron flux >= 0.6 Jansky. Comparison with simulations shows that our estimated errors on P(k) are realistic, and that systematic errors due to the finite survey volume are small for wavenumbers k >~ 0.03 h Mpc^-1. At large scales our power spectrum is intermediate between those of the earlier QDOT and 1.2 Jansky surveys, but with considerably smaller error bars; it falls slightly more steeply to smaller scales. We have fitted families of CDM-like models using the Peacock-Dodds formula for non-linear evolution; the results are somewhat sensitive to the assumed small-scale velocity dispersion \sigma_V. Assuming a realistic \sigma_V \approx 300 km/s yields a shape parameter \Gamma ~ 0.25 and normalisation b \sigma_8 ~ 0.75; if \sigma_V is as high as 600 km/s then \Gamma = 0.5 is only marginally excluded. There is little evidence for any `preferred scale' in the power spectrum or non-Gaussian behaviour in the distribution of large-scale power.Comment: Latex, uses mn.sty, 14 pages including 11 Postscript figures. Accepted by MNRA

    Taxonomic investigation of Ralfsia-like (Ralfsiales, Phaeophyceae) taxa in the North Atlantic Ocean based on molecular and morphological data, with descriptions of Pseudoralfsiaceae fam. nov., Pseudoralfsia azorica gen. et sp. nov. and Nuchella vesicularis gen. et sp. nov.

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    In this study we investigatedRalfsia-like crusts (i.e. excludingRalfsiasensu stricto,Stragulariaspp. and/or Scytosiphonaceae crustose phases) with an emphasis on the North Atlantic Ocean using molecular data (COI-5P, ITS andrbcL-3P) combined with morpho-anatomical comparisons of type material and contemporary specimens. Of the four species ofRalfsiapreviously reported in Europe, onlyR. fungiformisis presently recognized as belonging toRalfsiasensu stricto, Ralfsiaceae, with the remaining species,R. lucida, R. ovataandR. verrucosa, of uncertain taxonomic status. Our study revealed 11 independent genetic lineages ofRalfsia-like taxa, which were not assignable to any of the recognized families of the Ralfsiales. To accommodate this diversity, we propose Pseudoralfsiaceae Parente, Fletcher & G.W.Saunders fam. nov., including two new generaPseudoralfsiaParente, Fletcher & G.W.Saunders gen. nov. andNuchellaParente, Fletcher & G.W.Saunders gen. nov. The first genus includesPseudoralfsia verrucosa(Areschoug) Parente, Fletcher & G.W.Saunders comb. nov. as the generitype (the only species of the three remaining European species of uncertain taxonomic status assigned toRalfsiathat was reassessed here),P. azoricaParente, Fletcher & G.W.Saunders sp. nov. and seven undescribed genetic groups, which require additional vouchers for description. The second genus has as generitypeNuchella vesicularisParente, Fletcher & G.W.Saunders sp. nov., and also includesN. sp._1MP, which was represented by a single sterile specimen from Swanage, UK and consequently not characterized. Three characteristics differentiateNuchellafromPseudoralfsia- the former typically with numerous vesicles, non-synchronous development of the plurangia and hair pits arising from both middle and lower cells of the erect filaments. Species of Pseudoralfsiaceae can be distinguished fromRalfsiasensu stricto (Ralfsiaceae) mainly by DNA sequences and by consistently having frequent hair pits, and typically unsymmetrical thalli.This research was funded by FEDER funds through the Programa Operacional Factores de Competitividade - COMPETE and by national funds through FCT - Foundation for Science and Technology in the scope of the MACROBIOMOL project (ref. PTDC/MAR/114613/2009) and under the UID/BIA/50027/2013 and POCI-010145-FEDER-006821 programmes. Work completed in the Saunders Laboratory was supported by the Canadian Barcode of Life Network from Genome Canada in association with the Ontario Genomics Institute, the Natural Sciences and Engineering Research Council of Canada, as well as other sponsors listed at www.boldsystems.org, with infrastructure support from the Canada Foundation for Innovation and New Brunswick Innovation Foundation

    High prevalence of scrapie in a dairy goat herd: tissue distribution of disease-associated PrP and effect of PRNP genotype and age

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    Following a severe outbreak of clinical scrapie in 2006–2007, a large dairy goat herd was culled and 200 animals were selected for post-mortem examinations in order to ascertain the prevalence of infection, the effect of age, breed and PRNP genotype on the susceptibility to scrapie, the tissue distribution of diseaseassociated PrP (PrPd^{\rm d}), and the comparative efficiency of different diagnostic methods. As determined by immunohistochemical (IHC) examinations with Bar224 PrP antibody, the prevalence of preclinical infection was very high (72/200; 36.0%), with most infected animals being positive for PrPd^{\rm d} in lymphoreticular system (LRS) tissues (68/72; 94.4%) compared to those that were positive in brain samples (38/72; 52.8%). The retropharyngeal lymph node and the palatine tonsil showed the highest frequency of PrPd^{\rm d} accumulation (87.3% and 84.5%, respectively), while the recto-anal mucosa-associated lymphoid tissue (RAMALT) was positive in only 30 (41.7%) of the infected goats. However, the efficiency of rectal and palatine tonsil biopsies taken shortly before necropsy was similar. The probability of brain and RAMALT being positive directly correlated with the spread of PrPd^{\rm d} within the LRS. The prevalence of infection was influenced by PRNP genetics at codon 142 and by the age of the goats: methionine carriers older than 60 months showed a much lower prevalence of infection (12/78; 15.4%) than those younger than 60 months (20/42; 47.6%); these last showed prevalence values similar to isoleucine homozygotes of any age (40/80; 50.0%). Two of seven goats with definite signs of scrapie were negative for PrPd^{\rm d} in brain but positive in LRS tissues, and one goat showed biochemical and IHC features of PrPd^{\rm d} different from all other infected goats. The results of this study have implications for surveillance and control policies for scrapie in goats

    Endometriosis among African women

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    Endometriosis has long been wrongly perceived to be rare among women of African descent. The misconception about the prevalence of endometriosis among African women has significantly contributed to long diagnostic delays, limited access to diagnosis and care, and a scarcity of research on the condition among African women. In this commentary, we highlight the prevalence of endometriosis among African women, the state of endometriosis care in Africa, and the gaps in knowledge that need to be addressed. Based on the available data, the prevalence of endometriosis in Africa is likely higher than previously thought, with varying subtypes. There is a long diagnostic delay of endometriosis among African women. Additionally, endometriosis care in Africa from the general population and health practitioners is poor; this can be attributed to the high diagnostic cost, scarcity of trained specialists, as well as patients’ inability to express their symptoms due to societal taboos surrounding menstrual health. Public sensitization on endometriosis may help improve endometriosis diagnosis and care in Africa. LAY SUMMARY: Endometriosis is a condition in which tissue like the uterine lining is found outside the uterus, causing women to experience pain especially before, during, or after menstruation. Although endometriosis affects an estimated 176 million women worldwide, it has been wrongly reported that endometriosis is a rare condition among African women, mainly due to lack of awareness among healthcare providers and historical bias. In the current commentary, we discuss the prevalence of endometriosis, the diagnostic delays, and the care of endometriosis among black African women living in the African continent. Much of the literature has demonstrated (falsely) that endometriosis is rare in Black women compared to White ethnicity. African women experience a long diagnostic delay and do not receive appropriate care. Public awareness of endometriosis may help improve diagnosis delay and endometriosis care in Africa

    The Dipole Anisotropy of the 2mass Redshift Survey

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    We estimate the flux weighted acceleration on the Local Group (LG) from the near-infrared Two Micron All Sky Redshift Survey (2MRS). The near-infrared flux weighted dipoles are very robust because they closely approximate a mass weighted dipole, bypassing the effects of redshift distortions and require no preferred reference frame. We use this method with the redshift information to determine the change in dipole with distance. The LG dipole seemingly converges by 60 Mpc/h. Assuming convergence, the comparison of the 2MRS flux dipole and the CMB dipole provides a value for the combination of the mass density and luminosity bias parameters Omega_m^0.6/b_L= 0.40+/-0.09.Comment: 4 pages, 2 figures, Contribution to Rencontres de Moriond: Contents and Structures of the Universe, March 18-25, 2006, La Thuil

    Concurrent irinotecan, oxaliplatin and UFT in first-line treatment of metastatic colorectal cancer: a Phase I study

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    The feasibility of combining UFT plus leucovorin (LV) with alternating irinotecan and oxaliplatin was investigated in the first-line treatment of patients with advanced colorectal cancer. Twenty-five patients, median age 63 (range 24–79) years, World Health Organisation performance status 0–2 and median four marker lesions, received irinotecan 180 mg m−2 on day 1, oxaliplatin 85–100 mg m−2 on day 15 and UFT 200–300 mg m−2 day−1 with LV 90 mg day−1, days 1–21 of a 28-day cycle. Patients were treated in cohorts of three. At the highest dose (irinotecan 180 mg m−2, oxaliplatin 100 mg m−2 and UFT 300 mg m−2 day−1), three of four patients experienced grade 3 toxicity. Diarrhoea, lethargy and vomiting were dose-limiting. Three of nine patients had grade 2 toxicities at the maximum tolerated dose (irinotecan 180 mg m−2, oxaliplatin 100 mg m−2 and UFT 250 mg m−2 day−1). There were no grade 3 toxicities in the first month of therapy. The overall response rate was 71% in 21 evaluable patients; progression-free survival was 8.8 months. Alternating irinotecan and oxaliplatin plus UFT is an effective and well-tolerated first-line treatment for patients with advanced colorectal cancer. We recommend a dose of irinotecan 180 mg m−2 on day 1, oxaliplatin 100 mg m−2 on day 15 and UFT 250 mg m−2 day−1 with LV 90 mg day−1 on days 1–21 of a 28-day cycle for future studies

    High resolution mid-infrared spectroscopy of ultraluminous infrared galaxies

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    (Abridged) We present R~600, 10-37um spectra of 53 ULIRGs at z<0.32, taken using the IRS on board Spitzer. All of the spectra show fine structure emission lines of Ne, O, S, Si and Ar, as well as molecular Hydrogen lines. Some ULIRGs also show emission lines of Cl, Fe, P, and atomic Hydrogen, and/or absorption features from C_2H_2, HCN, and OH. We employ diagnostics based on the fine-structure lines, as well as the EWs and luminosities of PAH features and the strength of the 9.7um silicate absorption feature (S_sil), to explore the power source behind the infrared emission in ULIRGs. We show that the IR emission from the majority of ULIRGs is powered mostly by star formation, with only ~20% of ULIRGs hosting an AGN with a comparable or greater IR luminosity than the starburst. The detection of the 14.32um [NeV] line in just under half the sample however implies that an AGN contributes significantly to the mid-IR flux in ~42% of ULIRGs. The emission line ratios, luminosities and PAH EWs are consistent with the starbursts and AGN in ULIRGs being more extincted, and for the starbursts more compact, versions of those in lower luminosity systems. The excitations and electron densities in the NLRs of ULIRGs appear comparable to those of lower luminosity starbursts, though there is evidence that the NLR gas in ULIRGs is more dense. We show that the combined luminosity of the 12.81um [NeII] and 15.56um [NeIII] lines correlates with both IR luminosity and the luminosity of the 6.2 micron and 11.2 micron PAH features in ULIRGs, and use this to derive a calibration between PAH luminosity and star formation rate. Finally, we show that ULIRGs with 0.8 < S_sil < 2.4 are likely to be powered mainly by star formation, but that ULIRGs with S_sil < 0.8, and possibly those with S_sil > 2.4, contain an IR-luminous AGN.Comment: 62 pages in preprint format, 4 tables, 23 figures. ApJ accepte
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