157 research outputs found

    Moments of Autocorrelation Demerit Factors of Binary Sequences

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    Sequences with low aperiodic autocorrelation are used in communications and remote sensing for synchronization and ranging. The autocorrelation demerit factor of a sequence is the sum of the squared magnitudes of its autocorrelation values at every nonzero shift when we normalize the sequence to have unit Euclidean length. The merit factor, introduced by Golay, is the reciprocal of the demerit factor. We consider the uniform probability measure on the 22^\ell binary sequences of length \ell and investigate the distribution of the demerit factors of these sequences. Previous researchers have calculated the mean and variance of this distribution. We develop new combinatorial techniques to calculate the ppth central moment of the demerit factor for binary sequences of length \ell. These techniques prove that for p2p\geq 2 and 4\ell \geq 4, all the central moments are strictly positive. For any given pp, one may use the technique to obtain an exact formula for the ppth central moment of the demerit factor as a function of the length \ell. The previously obtained formula for variance is confirmed by our technique with a short calculation, and we demonstrate that our techniques go beyond this by also deriving an exact formula for the skewness.Comment: 40 page

    The Norian "chaotic carbon interval": New clues from the δ13Corg record of the Lagonegro Basin (southern Italy)

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    A global carbon-isotope curve for the Late Triassic has the potential for global correlations and new insights on the complex and extreme environmental changes that took place in this time interval. We reconstruct the global δ 13 C org profile for the late Norian, improving on sparse published data from North American successions that depict a "chaotic carbon-isotope interval" with rapid oscillations. In this context, we studied three sections outcropping in the Lagonegro Basin (southern Italy), originally located in the western Tethys. The carbon-isotope profiles show four negative excursions correlatable within the Lagonegro Basin. In particular, a negative shift close to the Norian/Rhaetian boundary (NRB) appears to correlate with that observed in the North American δ 13 C org record, documenting the widespread occurrence of this carbon cycle perturbation. The 87 Sr/ 86 Sr and 187 Os/ 188 Os profiles suggest that this negative shift was possibly caused by emplacement of a large igneous province (LIP). The release of greenhouse gases (CO 2 ) to the atmosphere-ocean system is supported by the 12 C enrichment observed, as well as by the increase of atmospheric p CO 2 inferred by different models for the Norian/Rhaetian interval. The trigger of this strongly perturbed interval could thus be enhanced magmatic activity that could be ascribed to the Angayucham province (Alaska, North America), a large oceanic plateau active ca. 214 ± 7 Ma, which has an estimated volume comparable to the Wrangellia and the Central Atlantic Magmatic Province (CAMP) LIPs. In fact, these three Late Triassic igneous provinces may have caused extreme environmental and climate changes during the Late Triassic

    Cenozoic Global Sea Level, Sequences, and the New Jersey Transect: Results from Coastal Plain and Continental Slope Drilling

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    The New Jersey Sea Level Transect was designed to evaluate the relationships among global sea level (eustatic) change, unconformity-bounded sequences, and variations in subsidence, sediment supply, and climate on a passive continental margin. By sampling and dating Cenozoic strata from coastal plain and continental slope locations, we show that sequence boundaries correlate (within ±0.5 myr) regionally (onshore-offshore) and interregionally (New Jersey-Alabama-Bahamas), implicating a global cause. Sequence boundaries correlate with δ18O increases for at least the past 42 myr, consistent with an ice volume (glacioeustatic) control, although a causal relationship is not required because of uncertainties in ages and correlations. Evidence for a causal connection is provided by preliminary Miocene data from slope Site 904 that directly link δ18O increases with sequence boundaries. We conclude that variation in the size of ice sheets has been a primary control on the formation of sequence boundaries since ∼42 Ma. We speculate that prior to this, the growth and decay of small ice sheets caused small-amplitude sea level changes (less than 20 m) in this supposedly ice-free world because Eocene sequence boundaries also appear to correlate with minor δ18O increases. Subsidence estimates (backstripping) indicate amplitudes of short-term (million-year scale) lowerings that are consistent with estimates derived from δ18O studies (25–50 m in the Oligocene-middle Miocene and 10–20 m in the Eocene) and a long-term lowering of 150–200 m over the past 65 myr, consistent with estimates derived from volume changes on mid-ocean ridges. Although our results are consistent with the general number and timing of Paleocene to middle Miocene sequences published by workers at Exxon Production Research Company, our estimates of sea level amplitudes are substantially lower than theirs. Lithofacies patterns within sequences follow repetitive, predictable patterns: (1) coastal plain sequences consist of basal transgressive sands overlain by regressive highstand silts and quartz sands; and (2) although slope lithofacies variations are subdued, reworked sediments constitute lowstand deposits, causing the strongest, most extensive seismic reflections. Despite a primary eustatic control on sequence boundaries, New Jersey sequences were also influenced by changes in tectonics, sediment supply, and climate. During the early to middle Eocene, low siliciclastic and high pelagic input associated with warm climates resulted in widespread carbonate deposition and thin sequences. Late middle Eocene and earliest Oligocene cooling events curtailed carbonate deposition in the coastal plain and slope, respectively, resulting in a switch to siliciclastic sedimentation. In onshore areas, Oligocene sequences are thin owing to low siliciclastic and pelagic input, and their distribution is patchy, reflecting migration or progradation of depocenters; in contrast, Miocene onshore sequences are thicker, reflecting increased sediment supply, and they are more complete downdip owing to simple tectonics. We conclude that the New Jersey margin provides a natural laboratory for unraveling complex interactions of eustasy, tectonics, changes in sediment supply, and climate change

    Stable isotopic response to late Eocene extraterrestrial impacts

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    We evaluated the age of two Upper Eocene impact ejecta layers (North American microtektites linked to the Chesapeake Bay impact structure and clinopyroxene [cpx] spherules from the Popigai crater) and the global effects of the associated impact events. The reported occurrence of cpx spherules from the Popigai impact structure at South Atlantic ODP Site 1090 within the middle of magnetochron C16n.1n yields a magnetochronologic age of 35.4 Ma. We generated high-resolution stable isotope records at Sites 1090, 612 (New Jersey slope), and Caribbean core RC9-58 that show: (1) a 0.5‰ δ^13C decrease in bulk-carbonate at Site 1090 coincident with the Popigai cpx spherule layer, and (2) a 0.4‰-0.5‰ decrease in deep-water benthic foraminiferal δ^13C values across the Popigai impact ejecta layer at Site 612 and core RC9-58. We conclude that the δ^13C excursion associated with Popigai was a global event throughout the marine realm that can be correlated to magnetochron C16n.1n. The amplitude of this excursion (~0.5‰) is within the limits of natural variability, suggesting it was caused by a decrease in carbon export productivity, potentially triggered by the impact event(s). North American microtektites associated with the Chesapeake Bay impact occur stratigraphically above the Popigai cpx spherules at Site 612 and core RC9-58. We found no definite evidence of a δ^13C anomaly associated with the North American microtektite layer, though further studies are warranted. High-resolution bulk-carbonate and benthic foraminiferal δ^18O records show no global temperature change associated with the cpx spherule or North American microtektite layers

    The Phanerozoic Record of Global Sea-Level Change

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    We review Phanerozoic sea-level changes [543 million years ago (Ma) to the present] on various time scales and present a new sea-level record for the past 100 million years (My). Long-term sea level peaked at 100 ± 50 meters during the Cretaceous, implying that ocean-crust production rates were much lower than previously inferred. Sea level mirrors oxygen isotope variations, reflecting ice-volume change on the 104- to 106-year scale, but a link between oxygen isotope and sea level on the 107-year scale must be due to temperature changes that we attribute to tectonically controlled carbon dioxide variations. Sea-level change has influenced phytoplankton evolution, ocean chemistry, and the loci of carbonate, organic carbon, and siliciclastic sediment burial. Over the past 100 My, sea-level changes reflect global climate evolution from a time of ephemeral Antarctic ice sheets (100 to 33 Ma), through a time of large ice sheets primarily in Antarctica (33 to 2.5 Ma), to a world with large Antarctic and large, variable Northern Hemisphere ice sheets (2.5 Ma to the present)

    Temperature calibration of Mg/Ca ratios in the intermediate water benthic foraminifer Hyalinea balthica

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    Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 12 (2011): Q04003, doi:10.1029/2010GC003333.Core top samples from Indonesian and northeast Atlantic depth transects were used to calibrate Mg/Ca and δ18O in tests of the calcitic benthic foraminifer Hyalinea balthica to bottom water temperature between 4°C and 13°C. This shallow infaunal species is primarily abundant in neritic to upper bathyal sediments (<600 m). Both linear and exponential calibrations suggest a temperature sensitivity of ~12% per °C that is ~4 times higher than observed in other species of deep-sea benthic foraminifera. Culture experiments support the core top calibration. We find no discernible effect of salinity and saturation on Mg/Ca. Comparison between the measured benthic foraminiferal δ18O and predicted equilibrium values suggests that on average H. balthica δ18O is 0.64‰ ± 0.13‰ lower than predicted from the equilibrium composition. To test the reliability of using paired H. balthica Mg/Ca and δ18O measurements for reconstructing seawater δ18Osw and salinity, we apply this calibration to another depth transect from Cape Ghir off NW Africa, which was not included in the calibration. Based on error analysis of the calibration data and this validation test, we show that the uncertainty of reconstructing bottom water temperature and salinity from paired Mg/Ca and δ18O measurements of H. balthica is better than ±0.7°C and ±0.69 practical salinity scale, respectively. The small uncertainties allow for the reconstruction of seawater density to better than 0.3σθ units, which is precise enough for the identification of specific water masses and reconstruction of changes in their properties. We propose that the relatively high Mg content and temperature sensitivity of H. balthica might be due to minor, biologically mediated contribution of high-Mg calcite to the primarily low Mg calcite test, which is influenced by the ambient temperature. This hypothesis, if correct, suggests that benthic species with relatively high Mg/Ca may be better suited for deepwater temperature reconstructions than species that have thus far been more commonly used.This project was funded by NSF Awards OCE 02‐20922 and 09‐02977 to YR, OCE 09‐28607 to MK, OCE02‐20776 to DWO, and DFG priority program INTERDYNAMIK to AM

    The TREAT-NMD DMD Global Database: analysis of more than 7,000 Duchenne muscular dystrophy mutations.

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    Analyzing the type and frequency of patient-specific mutations that give rise to Duchenne muscular dystrophy (DMD) is an invaluable tool for diagnostics, basic scientific research, trial planning, and improved clinical care. Locus-specific databases allow for the collection, organization, storage, and analysis of genetic variants of disease. Here, we describe the development and analysis of the TREAT-NMD DMD Global database (http://umd.be/TREAT_DMD/). We analyzed genetic data for 7,149 DMD mutations held within the database. A total of 5,682 large mutations were observed (80% of total mutations), of which 4,894 (86%) were deletions (1 exon or larger) and 784 (14%) were duplications (1 exon or larger). There were 1,445 small mutations (smaller than 1 exon, 20% of all mutations), of which 358 (25%) were small deletions and 132 (9%) small insertions and 199 (14%) affected the splice sites. Point mutations totalled 756 (52% of small mutations) with 726 (50%) nonsense mutations and 30 (2%) missense mutations. Finally, 22 (0.3%) mid-intronic mutations were observed. In addition, mutations were identified within the database that would potentially benefit from novel genetic therapies for DMD including stop codon read-through therapies (10% of total mutations) and exon skipping therapy (80% of deletions and 55% of total mutations)

    Uptake of hysterectomy and bilateral salpingooophorectomy in carriers of pathogenic mismatch repair variants:a Prospective Lynch Syndrome Database report

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    Purpose: This study aimed to report the uptake of hysterectomy and/or bilateral salpingo-oophorectomy (BSO) to prevent gynaecological cancers (risk-reducing surgery [RRS]) in carriers of pathogenic MMR (path_MMR) variants. Methods: The Prospective Lynch Syndrome Database (PLSD) was used to investigate RRS by a cross-sectional study in 2292 female path_MMR carriers aged 30-69 years. Results: Overall, 144, 79, and 517 carriers underwent risk-reducing hysterectomy, BSO, or both combined, respectively. Two-thirds of procedures before 50 years of age were combined hysterectomy and BSO, and 81% of all procedures included BSO. Risk-reducing hysterectomy was performed before age 50 years in 28%, 25%, 15%, and 9%, and BSO in 26%, 25%, 14% and 13% of path_MLH1, path_MSH2, path_MSH6, and path_PMS2 carriers, respectively. Before 50 years of age, 107 of 188 (57%) BSO and 126 of 204 (62%) hysterectomies were performed in women without any prior cancer, and only 5% (20/392) were performed simultaneously with colorectal cancer (CRC) surgery. Conclusion: Uptake of RRS before 50 years of age was low, and RRS was rarely undertaken in association with surgical treatment of CRC. Uptake of RRS aligned poorly with gene-and age-associated risk estimates for endometrial or ovarian cancer that were published recently from PLSD and did not correspond well with current clinical guidelines. The reasons should be clarified. Decision-making on opting for or against RRS and its timing should be better aligned with predicted risk and mortality for endometrial and ovarian cancer in Lynch syn-drome to improve outcomes. (C) 2021 The Author(s). Published by Elsevier Ltd

    Intersocietal consensus on the treatment of obesity in adolescents in Argentina

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    En un contexto socioeconómico mundial de profundas desigualdades, mientras que poblaciones enteras están siendo arrasadas por la desnutrición, es notorio el aumento de la obesidad en niños, adolescentes y adultos. La prevalencia de obesidad ha aumentado a un ritmo alarmante y está afectando progresivamente a muchos países de bajos y medianos ingresos, sobre todo en el medio urbano. Preocupa, especialmente de bido a las severas complicaciones clínicas que ocasiona1,2. De manera coincidente con las tendencias internacionales, en la Argentina la 2º Encuesta Nacional de Nutrición y Salud ( ENNYS) del año 2019 revela cifras del 20,7% y 20,4% de sobrepeso y obesidad en niños de 5 a 17 años, y en la tercera Encuesta Mundial de Salud Escolar del 2018 ( EMSE) , las cifras de la población de 13 a 17 años fueron de 30,7 % de sobrepeso y 7,4 % de obesidad3,4. La obesidad es una enfermedad crónica. Recientemente, la Asociación Europea para el Estudio de la Obesidad (EASO), la resume como una enfermedad por exceso de tejido adiposo. Las severas consecuencias en la salud que provoca dependen de la cantidad, la distribución y la localización del tejido adiposo. La enfermedad se produce, tanto a partir de la alteración en la función endócrina e inmulogógica del organismo, como causando alteraciones anatómicas en el organismo a partir del espacio físico que ocupa...Fil: Kovalskys, Irina. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; ArgentinaFil: Mayer, Marcos Alejandro. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Confluencia. Instituto de Ciencias de la Tierra y Ambientales de la Pampa. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas | Universidad Nacional de la Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de la Pampa. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas.; ArgentinaFil: Armeno, Marisa. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Matto, Liliana. Asociación Psiquiátrica de América Latina; Argentina. Asociación de Psiquiatras Argentinos; ArgentinaFil: Roussos, Adriana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Schuldberg, Jacqueline. Asociación Argentina de Dietistas- Nutricionistas Dietistas; ArgentinaFil: Tozzi, Karina. Sociedad Argentina de Endocrinología Ginecológica y Reproductiva; ArgentinaFil: Valenti, Claudia. Gobierno de la Ciudad Autonoma de Buenos Aires. Ministerio de Salud. Subsecretaria de Atencion Primaria Ambulatoria y Comunitaria.; ArgentinaFil: Anger, Vanesa E.. Universidad Maimónides; ArgentinaFil: Araujo, María Beatriz. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Bakalarz, Beatriz. Asociación Psiquiatras Argentinos; ArgentinaFil: Bazan, Nelio Eduardo. Universidad Nacional de Rosario; ArgentinaFil: Ganduglia Cazaban, Mercedes. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); Argentina. Asociación Argentina de Nutricionistas y Nutricionistas Dietistas; ArgentinaFil: Ozuna, Blanca Acela. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Rampi, Gabriela. Universidad Austral. Hospital Universitario Austral; ArgentinaFil: Ruiz, Laura. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Sarubbi, Susana. Sociedad Argentina de Nutrición; ArgentinaFil: Tonietti, Miriam. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Zonis, Luciana. Sociedad Argentina de Nutrición; ArgentinaFil: Salinas, Victoria. Sociedad Argentina de Nutrición; ArgentinaFil: Aguirre Ackermann, Marianela. Sociedad Argentina de Nutrición; Argentina. Universidad Nacional del Nordeste; Argentina. Universidad Favaloro; ArgentinaFil: Sguassero, Yanina. Sociedad Argentina de Nutrición; ArgentinaFil: Katz, Mónica. Sociedad Argentina de Nutrición; Argentina. Universidad Favaloro; Argentin
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