4,736 research outputs found
From natural hazard to environmental catastrophe: Past and present
No full textThe number of environmental catastrophes is rising, mostly owing to an increase in hydrometeorological hazards. The number of disasters is escalating as the world population grows and people settle in marginal areas. In order to improve preparedness, the geological and archaeological records must be investigated as they hold a wider range of possible events than the much shorter instrumental record. Catastrophes will gain amplitude with rapid onset, long duration, larger affected area, inflexible society and, of cause, convergence of threats. Too often, it seems that today’s societies resist learning from the past and therefore tend to repeat errors. A new field of science is emerging: the science of environmental catastrophes, which requires not only robust chronologies to firmly link cause and effect, but also bridges the crossing between the geosciences and social sciences
River inflow and salinity changes in the Caspian Sea during the last 5500 years
No full textPollen, spores and dinoflagellate cysts have been analysed on three sediment cores (1.8–1.4 m-long) taken from the south and middle basins of the Caspian Sea. A chronology available for one of the cores is based on calibrated radiocarbon dates (ca 5.5–0.8 cal. ka BP). The pollen and spores assemblages indicate fluctuations between steppe and desert. In addition there are some outstanding zones with a bias introduced by strong river inflow. The dinocyst assemblages change between slightly brackish (abundance of Pyxidinopsis psilata and Spiniferites cruciformis) and more brackish (dominance of Impagidinium caspienense) conditions. During the second part of the Holocene, important flow modifications of the Uzboy River and the Volga River as well as salinity changes of the Caspian Sea, causing sea-level fluctuations, have been reconstructed. A major change is suggested at ca 4 cal. ka BP with the end of a high level phase in the south basin. Amongst other hypotheses, this could be caused by the end of a late and abundant flow of the Uzboy River (now defunct), carrying to the Caspian Sea either meltwater from higher latitudes or water from the Amu-Daria. A similar, later clear phase of water inflow has also been observed from 2.1 to 1.7 cal. ka BP in the south basin and probably also in the north of the middle basin
Ocular involvement in systemic sclerosis: A systematic literature review, it's not all scleroderma that meets the eye
No full textObjectives: Systemic sclerosis (SSc) is a rare and complex autoimmune disorder characterized by microvascular damage and progressive fibrosis which affects the skin and multiple other organs. Much of the published data concerning SSc and the eye consists of single case reports or small case studies. This systematic review aims to provide an overview of the current level of evidence for SSc-related ocular changes.
Materials and methods: A systematic literature review was conducted using 3 electronic databases, according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. A combination of following keywords was used: “Systemic Sclerosis” and ophthalmology-related search terms, including the keywords “Eye”, “Ocular” and “Ophthalmic”. All articles were screened by 2 independent reviewers at title, abstract and full text level. We solely included case-control studies that investigated specific ocular findings in SSc patients compared to healthy controls.
Results: Nine of 270 articles were retained. Dry eye symptoms are associated with SSc, whereas objective signs (Schirmer I testing) show conflicting results. There is insufficient evidence of SSc-related changes to the central corneal thickness. In terms of posterior segment involvement, choroidal vasculature appears to be affected to greater extent than the retinal microcirculation. However, the limited number of patients included in the studies renders it hazardous to draw overall conclusions.
Conclusions: There is a paucity of well-designed case-control studies investigating possible ocular involvement in SSc. Our systematic review demonstrates limited proven associations between SSc and ocular abnormalities, mainly in terms of dry eye symptoms and choroidal thickness. Future standardized prospective studies are needed to clarify the impact of the disease on the eye
Data for: Dinocyst records from deep cores reveal a reversed salinity gradient in the Caspian Sea at 8.5 – 4.0 cal. ka BP
No full textfor core Sh7, I provide grain size, pollen and dinocysts.For core GS18, I provide the dinocyst data for the whole cor
Autoantibody profile differentiates BP phenotypes
No full textBullous pemphigoid (BP) is a major autoimmune blistering skin disorder, in which a majority of the autoantibodies (autoAbs) target the juxtamembranous extracellular noncollagenous 16A domain (NC16A) domain of hemidesmosomal collagen XVII. BP-autoAbs may target regions of collagen XVII other than the NC16A domain; however, correlations between epitopes of BP-autoAbs and clinical features have not been fully elucidated. To address correlations between the clinical features and specific epitopes of BP-autoAbs, we evaluated the epitope profiles of BP-autoAbs in 121 patients. A total of 87 patients showed a typical inflammatory phenotype with erythema and autoAbs targeting the anti-NC16A domain, whereas 14 patients showed a distinct noninflammatory phenotype, in which autoAbs specifically targeted the midportion of collagen XVII, but not NC16A. Interestingly, this group clinically showed significantly reduced erythema associated with scant lesional infiltration of eosinophils. Surprisingly, 7 of the 14 cases (50.0%) received dipeptidyl peptidase-IV inhibitors for the treatment of diabetes. Dipeptidyl peptidase-IV inhibitors were used in 3 of 76 (3.9%) typical cases of BP with autoAbs targeting NC16A; thus, dipeptidyl peptidase-IV inhibitors are thought to be involved in the development of atypical noninflammatory BP. This study shows that the autoAb profile differentiates between inflammatory and noninflammatory BP, and that noninflammatory BP may be associated with dipeptidyl peptidase-IV inhibitors
Link prediction in author collaboration network based on BP neural network
No full textRecently, more and more authors have been encouraged for collaboration because it often produces good results. However, the author collaboration network contains experts in various research directions within various fields, and it is difficult for individual authors to decide which authors are best suited to their expertise. This paper uses the relationships among authors to predict new relationships that may arise, recommending each author with the collaborators they may be interested in. The data source comes from 4-year data in DBLP from 2001 to 2004. After data cleaning, the training set and test set are constructed and then used BP neural network to build model. At the same time, this article compares the performance with Logistic Regression, SVM and Random Forest. The experiment shows that the BP neural network can get better result, and it is feasible to predict links in the author collaboration network
Link prediction in author collaboration network based on BP neural network
No full textRecently, more and more authors have been encouraged for collaboration because it often produces good results. However, the author collaboration network contains experts in various research directions within various fields, and it is difficult for individual authors to decide which authors are best suited to their expertise. This paper uses the relationships among authors to predict new relationships that may arise, recommending each author with the collaborators they may be interested in. The data source comes from 4-year data in DBLP from 2001 to 2004. After data cleaning, the training set and test set are constructed and then used BP neural network to build model. At the same time, this article compares the performance with Logistic Regression, SVM and Random Forest. The experiment shows that the BP neural network can get better result, and it is feasible to predict links in the author collaboration network
From the Allerød to the mid-Holocene: Palynological evidence from the south basin of the Caspian Sea
No full textThis article has been made available through the Brunel Open Access Publishing Fund. Copyright @ The Authors. This is an open-access article distributed under the terms of the Creative
Commons Attribution-NonCommercial-No Derivative Works License, which permits
non-commercial use, distribution, and reproduction in any medium, provided
the original author and source are credited.Pollen and dinoflagellate cysts have been analysed in a core from the south basin of the Caspian Sea, providing a picture of respectively past vegetation and water salinity for the Late Pleistocene to middle Holocene. A relatively sharp lithological change at 0.86 m depth reflects a shift from detrital silts to carbonates-rich fine silts. From this depth upwards, a Holocene chronology is built based on ten radiocarbon dates on ostracod shells and bulk carbonates. From the vegetation point of view, the Late Pleistocene deserts and steppes were partially replaced in the most sheltered areas by an open woodland with Pinus, Juniperus-Hippophae-Elaeagnus and even Alnus-Quercus-Pterocarya and Fraxinus, related to the Allerød palynozone. This was interrupted by the Younger Dryas palynozone when Artemisia reaches a maximum in a first instance followed by a very dry phase with only a slight return of Pinus and Quercus and the rare presence of Ulmus-Zelkova. From 11.5 to 8.4 cal. ka BP, an open landscape dominated by shrubs such as Ephedra and progressively increasing Quercus appeared. The final spread of diverse evergreen and deciduous trees is delayed and occurs after 8.4 cal. ka BP. It is suggested that this delay is caused by an arid climate in the Early Holocene linked to high insolation and perhaps to a lake effect. The dinocyst assemblages fluctuate between slightly brackish (Pyxidinopsis psilata and Spiniferites cruciformis, 7 psu and lower) and more brackish (Impagidinium caspienense, ∼13 psu). In the Lateglacial (Khvalynian highstand), the assemblages remained dominated by relative low salinity taxa. A late and brief increase of salinity occurred prior to 11.2 cal. ka BP associated with the Mangyshlak lowstand. It is suggested that it was caused by a brief drop in meltwater flow from both the north and the southeast (Uzboy) and a likely evaporation increase. This lowstand occurs quasi at the same time as the end of a longer lowstand in the Black Sea. The freshest waters are then inferred as having occurred between 8.4 and ≤4.4 cal. ka BP, linked to a connection with the Amu Darya and the melting glaciers on the Pamir Mountains. The Caspian Sea is a sensitive environment, easily perturbed by global climatic changes, such as the Allerød and Holocene warming, and the Lateglacial and Younger Dryas cooling, as well as by regional changes in its hydrography, such as shifts in the Eurasian meltwater and the Volga and Amu Darya inflows.Centre National de la Recherche Scientifique, Franc
Uniqueness of BP⟨n⟩
No full textFix a prime number p and an integer n≥ 0. We prove that if a p-complete spectrum X satisfying a mild finiteness condition has the same mod p cohomology as BP⟨ n⟩ as a module over the Steenrod algebra, then X is weak homotopy equivalent to the p-completion of BP⟨ n⟩.The first author was supported by an ARC Discovery grant. The
second author was partially supported by the DFG through SFB-1085, and thanks the Australian National
University for hosting him while this research was conducted
IntCal09 and Marine09 radiocarbon age calibration curves, 0–50,000 years cal BP
No full textAuthor Posting. © Arizona Board of Regents on behalf of the University of Arizona, 2009. This article is posted here by permission of Dept. of Geosciences, University of Arizona for personal use, not for redistribution. The definitive version was published in Radiocarbon 51 (2009): 1111-1150.The IntCal04 and Marine04 radiocarbon calibration curves have been updated from 12 cal kBP (cal kBP is
here defined as thousands of calibrated years before AD 1950), and extended to 50 cal kBP, utilizing newly available data sets
that meet the IntCal Working Group criteria for pristine corals and other carbonates and for quantification of uncertainty in
both the 14C and calendar timescales as established in 2002. No change was made to the curves from 0–12 cal kBP. The curves
were constructed using a Markov chain Monte Carlo (MCMC) implementation of the random walk model used for IntCal04
and Marine04. The new curves were ratified at the 20th International Radiocarbon Conference in June 2009 and are available
in the Supplemental Material at www.radiocarbon.org.We would like to acknowledge support for this project from the UK Natural Environment Research
Council NE/E018807/1 and IGBP PAGES (Past Global Changes)
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