2,439 research outputs found
Hypercube technology
The JPL designed MARKIII hypercube supercomputer has been in application service since June 1988 and has had successful application to a broad problem set including electromagnetic scattering, discrete event simulation, plasma transport, matrix algorithms, neural network simulation, image processing, and graphics. Currently, problems that are not homogeneous are being attempted, and, through this involvement with real world applications, the software is evolving to handle the heterogeneous class problems efficiently
Foraminiferal Evidence of Younger Dryas Age Cooling on the British Columbia Shelf
Cluster analysis of foraminifera from a ~12,000-9000 radiocarbon year old piston core from Goose Island Trough, Queen Charlotte Sound, indicates that a cold interval correlative with the Younger Dryas stadial occurred during a shallow water phase. The reduction in depth was caused by the passage across the area, between 11,500 and 10,000 years BP, of a glacial forebulge associated with the retreat of the Late Wisconsinian ice sheets. Published sedimentological evidence indicate that water depths decreased to ~75-90 m, placing the site above the permanent North Pacific pycnocline (100 m). Low salinity-near glacial conditions, at these depths, between -11,100 and 10,000 years BP were recognized by abundant populations of Cassidulina reniforme and lslandiella helenae. This cold interval has also been recognized in cores from elsewhere in Queen Charlotte Sound. The depressed salinity and temperature may have resulted from a modification of regional weather patterns. Decreased mean continental summer temperatures could have reduced the seasonal influence of the North Pacific High and lengthened that of the Aleutian Low. This would have resulted in a near continuous onshore surface Ekman transport and enhanced coastal runoff, effectively blocking the movement onto the shelf of deep, saline, warm water of the California Undercurrent. The resultant isolated inshore basin comprised of present-day Hecate Strait and Queen Charlotte Sound is tentatively named the "Hecate Sea". By ~10,000 years BP, weather and ocean circulation had returned to near modern patterns as indicated by the disappearance of lslandiella helenae and by the development of an Epistominella vitrea - dominated biofacies.L'analyse des groupements effectuée sur des populations de foraminifères d'une carotte à piston couvrant la période de 12 000 à 9000 ans BP, provenant du Goose Island Trough, dans le bassin de la Reine-Charlotte, démontre l'existence d'un intervalle froid contemporain du Dryas récent. Il coïncide avec une phase à bathymétrie réduite qui résulte du déplacement vers l'est, entre 11 500 et 10 000 ans BP, du bombement isostatique associé à l'Inlandsis de la Cordillière à la suite de son retrait. Des données sédimentologiques publiées montrent que la profondeur a diminué jusqu'à ~75-90 m, amenant le site étudié au-dessus de la pycnocline permanente du Pacifique Nord (100 m). L'existence de conditions hyposalines de type glaciaire, à ces profondeurs, entre 11 100 et 10 000 ans BP ont été reconnues grâce à la présence d'assemblages à Cassidulina reniforme et lslandiella helenae. Cet intervalle froid a également été reconnu ailleurs dans le bassin de la Reine-Charlotte. Les salinités et les températures réduites sont peut-être le résultat d'un changement dans les configurations météorologiques régionales. Des températures estivales plus basses sur le continent auraient réduit l'influence saisonnière de l'anticyclone du Pacifique Nord et rallongé celle de la dépression des Aloutiennes. Ceci aurait engendré un transport d'Ekman de surface quasi permanent vers la côte et provoqué une augmentation des précipitations, ayant eu pour effet de bloquer la remontée des eaux salées et tièdes du sous-courant de Californie. Nous proposons d'appeler « Mer d'Hécate » le bassin côtier ainsi créé comprenant l'actuel détroit d'Hécate et le bassin de la Reine-Charlotte. Dès avant ~10 000 ans BP, les circulations atmosphérique et océanique étaient revenues à une configuration presque moderne.Die Analyse der Foraminiferen-Anhàufungen von einem -12,000-9000 Radiokarbonjahre alten Bohrkern von Goose Island Trough im Queen Charlotte Sund zeigt, daB ein kaltes Intervall gleichzeitig mit dem jùngeren Dryas-Stadium wàhrend einer Phase seichten Wassers eintrat. Die Verringerung der Tiefe wurde durch die Passage einer glazialen Emporwôlbung zwischen 11,500 und 10,000 Jahren v.u.Z. quer durch das Gebiet bewirkt, zusammen mit dem Rùckzug der Eisdecken vom spàten Wisconsinium. Die verôfent-lichten sedimentologischen Belege zeigen, daf3 die Wassertiefen auf -75-90 m abnahmen, und so den Platz ùber die stàndige Dichte-Gradient des Nordpazifik (100 m) stellten. Fast glaziale Bedingungen mit niedrigem Salzgehalt wurden in diesen Tiefen zwischen -11,100 und 10,000 Jahren v.u.Z. auf Grund von reichlichen Populationen von Cassidulina reniforme und lslandiella helenae erkannt. Der verringerte Salzgehalt und die niedrigere Temperatur kônnten auch durch eine Ànderung der regionalen Wetterkonstellationen bewirkt worden sein. Gesunkene durchschnittliche kontinentale Sommertemperaturen kônnten den jahreszeitlichen EinfluB des nordpazifischen Hochs verringert und den des atlantischen Tiefs verlàngert haben. Das kônnte einen fast kontinuierlichen Ekman-Transport an der Oberflâche zur Kùste hin bewirkt und die Kùsten-Niederschlàge verstàrkt haben, und so ware die Bewegung von tiefem, salzhaltigem warmem Wasser der kalifornischen Unterstromung zur Terrasse hin blockiert worden. Das daraus resultierende isolierte Binnen-Becken, bestehend aus der heutigen Hecate-Meerenge und dem Queen Charlotte Sund, wird probeweise "Hecate Sea" genannt. Um -10,000 Jahre v.u.Z. sind Wetter und Ozeanstromung zu nahezu modernen Mustern zuruckgekehrt
Hypercube matrix computation task
A major objective of the Hypercube Matrix Computation effort at the Jet Propulsion Laboratory (JPL) is to investigate the applicability of a parallel computing architecture to the solution of large-scale electromagnetic scattering problems. Three scattering analysis codes are being implemented and assessed on a JPL/California Institute of Technology (Caltech) Mark 3 Hypercube. The codes, which utilize different underlying algorithms, give a means of evaluating the general applicability of this parallel architecture. The three analysis codes being implemented are a frequency domain method of moments code, a time domain finite difference code, and a frequency domain finite elements code. These analysis capabilities are being integrated into an electromagnetics interactive analysis workstation which can serve as a design tool for the construction of antennas and other radiating or scattering structures. The first two years of work on the Hypercube Matrix Computation effort is summarized. It includes both new developments and results as well as work previously reported in the Hypercube Matrix Computation Task: Final Report for 1986 to 1987 (JPL Publication 87-18)
Paleosalinity History of Middle Holocene Lagoonal and Lacustrine Deposits in the Enriquillo Valley, Dominican Republic Based on Pore Morphometrics and Isotope Geochemistry of Ostracoda
The southwestern region of the Dominican Republic (Enriquillo Valley) contains exceptionally well-preserved, relict marine and saline lake deposits of mid-Holocne age. Abundant euryhaline ostracodes found in this deposit include Cyprideis salebrosa, C. mexicana, C. similis, and C. edentata. Morphometric and geochemical analyses performed on Cyprideis spp. provide high δ18O and δ13C values that are coincident with relative abundances of irregularly shaped pores that permeate the ostracode carapace. We recognize three stratigraphic intervals with distinct ostracode pore shape and stable isotope trends: (I) a 4.5-5.0m interval that contains ostracodes with highly irregular shaped pores (multiradiate) and high amplitude variability in δ18O and δ13C values; (II) a 5.0-5.6m interval comprised of ostracodes with circular pores and an overall trend towards low δ18O and δ13C values; and (III) a 5.6-6.5m interval containing ostracodes with an upward increasing abundance of circular pore shapes coincident with decreasing δ18O and δ13C values. When the Enriquillo lagoon was first separated from the Caribbean Sea approximately 4.3 ka, an arid and evaporative climate led to hypersaline water in a restricted lagoon environment. By the middle to late-Holocene, increased precipitation in the valley resulted in a coastal lake system that became progressively oligohaline. Moderate to small amplitude variability in the salinity proxy data (δ18O) suggest short-term oscillations in the precipitation-evaporation budgets at that time. At least two marine incursions likely contributed to the ob- served variability in ostracode δ18O and δ13C values. Evidence for abrupt changes in base level indicate that climatic factors or also tectonic activity may have contributed to the observed paleoenvironmental trends recorded in these deposits
The Lantern Vol. 10, No. 1, December 1941
• Misty • The Evils of Initiations • Ursinus, Fifty Years Ago • My Conversion • Our Gang • From Rabble to Royalty • So You Want to be an Editor! • Tempo • A Musician\u27s Allegory • Flotsam • The Years • Common Things • Sea Moods • Aunt Agatha\u27s Pillow • Peace at Autumn Twilighthttps://digitalcommons.ursinus.edu/lantern/1025/thumbnail.jp
Ecology Drives the Worldwide Distribution of Human Diseases
Identifying the factors underlying the origin and maintenance of the latitudinal diversity gradient is a central problem in ecology, but no consensus has emerged on which processes might generate this broad pattern. Interestingly, the vast majority of studies exploring the gradient have focused on free-living organisms, ignoring parasitic and infectious disease (PID) species. Here, we address the influence of environmental factors on the biological diversity of human pathogens and their global spatial organization. Using generalized linear multivariate models and Monte Carlo simulations, we conducted a series of comparative analyses to test the hypothesis that human PIDs exhibit the same global patterns of distribution as other taxonomic groups. We found a significant negative relationship between latitude and PID species richness, and a nested spatial organization, i.e., the accumulation of PID species with latitude, over large spatial scales. Additionally, our results show that climatic factors are of primary importance in explaining the link between latitude and the spatial pattern of human pathogens. Based on our findings, we propose that the global latitudinal species diversity gradient might be generated in large part by biotic interactions, providing strong support for the idea that current estimates of species diversity are substantially underestimated. When parasites and pathogens are included, estimates of total species diversity may increase by more than an order of magnitude
The impact of iron supplementation efficiency in female blood donors with a decreased ferritin level and no anaemia. Rationale and design of a randomised controlled trial: a study protocol
ABSTRACT: BACKGROUND: There is no recommendation to screen ferritin level in blood donors, even though several studies have noted the high prevalence of iron deficiency after blood donation, particularly among menstruating females. Furthermore, some clinical trials have shown that non-anaemic women with unexplained fatigue may benefit from iron supplementation. Our objective is to determine the clinical effect of iron supplementation on fatigue in female blood donors without anaemia, but with a mean serum ferritin </= 30 ng/ml. METHODS/DESIGN: In a double blind randomised controlled trial, we will measure blood count and ferritin level of women under age 50 yr, who donate blood to the University Hospital of Lausanne Blood Transfusion Department, at the time of the donation and after 1 week. One hundred and forty donors with a ferritin level </= 30 ng/ml and haemoglobin level >/= 120 g/l (non-anaemic) a week after the donation will be included in the study and randomised. A one-month course of oral ferrous sulphate (80 mg/day of elemental iron) will be introduced vs. placebo. Self-reported fatigue will be measured using a visual analogue scale. Secondary outcomes are: score of fatigue (Fatigue Severity Scale), maximal aerobic power (Chester Step Test), quality of life (SF-12), and mood disorders (Prime-MD). Haemoglobin and ferritin concentration will be monitored before and after the intervention. DISCUSSION: Iron deficiency is a potential problem for all blood donors, especially menstruating women. To our knowledge, no other intervention study has yet evaluated the impact of iron supplementation on subjective symptoms after a blood donation. TRIAL REGISTRATION: NCT00689793
Framework for Leadership and Training of Biosafety Level 4 Laboratory Workers
One-sentence summary for table of contents: Training should include theoretical consideration of biocontainment principles, practical hands-on training, and mentored on-the-job experience
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Miscarriage and stillbirth following maternal Zika virus infection in nonhuman primates.
Zika virus (ZIKV) infection is associated with congenital defects and pregnancy loss. Here, we found that 26% of nonhuman primates infected with Asian/American ZIKV in early gestation experienced fetal demise later in pregnancy despite showing few clinical signs of infection. Pregnancy loss due to asymptomatic ZIKV infection may therefore be a common but under-recognized adverse outcome related to maternal ZIKV infection
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Hyperpolarized 13C-MRI of Tumor Metabolism Demonstrates Early Metabolic Response to Neoadjuvant Chemotherapy in Breast Cancer
Purpose: To compare hyperpolarized carbon-13 (13C)-MRI with dynamic contrast-enhanced MRI (DCE-MRI) for detecting early treatment response in breast cancer.
Materials and Methods: In this institutional review board-approved prospective study, one woman with triple-negative breast cancer (age 49) underwent 13C-MRI following injection of hyperpolarized [1-13C]pyruvate and DCE-MRI at 3 T at baseline and after a single cycle of neoadjuvant therapy. The 13C-lactate/13C-pyruvate ratio derived from hyperpolarized 13C-MRI and the pharmacokinetic parameters Ktrans and kep derived from DCE-MRI were compared, before and after treatment.
Results: Exchange of the 13C-label between injected hyperpolarized [1-13C]pyruvate and the endogenous lactate pool was demonstrated, catalyzed by the enzyme lactate dehydrogenase. After one cycle of neoadjuvant chemotherapy, a 34% reduction in the 13C-lactate/13C-pyruvate ratio was shown to correctly identify the patient as a responder to therapy, which was subsequently confirmed by a complete pathologic response. However, DCE-MRI showed an increase in the pharmacokinetic parameters Ktrans (132%) and kep (31%), which could be incorrectly interpreted as a poor response to treatment.
Conclusion: Hyperpolarized 13C-MRI successfully identified response in breast cancer after a single cycle of neoadjuvant chemotherapy and may improve response prediction when used in conjunction with multiparametric proton MRI.This work was supported by a Wellcome Trust Strategic Award, Cancer Research UK (CRUK; Grants C8742/A18097, C19212/ A16628, C19212/A911376, and C197/A16465), the Austrian Science Fund (Grant J4025-B26), the CRUK Cambridge Centre, the CRUK & Engineering and Physical Sciences Research Council Cancer Imaging Centre in Cambridge and Manchester, the Mark Foundation for Cancer Research and Cancer Research UK Cambridge Centre (Grant C9685/A25177), CRUK National Cancer Imaging Translational Accelerator Award, Addenbrooke’s Charitable Trust, the National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge Experimental Cancer Medicine Centre, and Cambridge University Hospitals National Health Service Foundation Trust
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