989 resultados para Patricio, Santo, ca. 390-ca. 461


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Arctic Ocean freshening can exert a controlling influence on global climate, triggering strong feedbacks on ocean-atmospheric processes and affecting the global cycling of the world's oceans. Glacier-fed ocean currents such as the Alaska Coastal Current are important sources of freshwater for the Bering Sea shelf, and may also influence the Arctic Ocean freshwater budget. Instrumental data indicate a multiyear freshening episode of the Alaska Coastal Current in the early 21st century. It is uncertain whether this freshening is part of natural multidecadal climate variability or a unique feature of anthropogenically induced warming. In order to answer this, a better understanding of past variations in the Alaska Coastal Current is needed. However, continuous long-term high-resolution observations of the Alaska Coastal Current have only been available for the last 2 decades. In this study, specimens of the long-lived crustose coralline alga Clathromorphum nereostratum were collected within the pathway of the Alaska Coastal Current and utilized as archives of past temperature and salinity. Results indicate that coralline algal Mg/Ca ratios provide a 60 year record of sea surface temperatures and track changes of the Pacific Decadal Oscillation, a pattern of decadal-to-multidecadal ocean-atmosphere climate variability centered over the North Pacific. Algal Ba/Ca ratios (used as indicators of coastal freshwater runoff) are inversely correlated to instrumentally measured Alaska Coastal Current salinity and record the period of freshening from 2001 to 2006. Similar multiyear freshening events are not evident in the earlier portion of the 60 year Ba/Ca record. This suggests that the 21st century freshening of the Alaska Coastal Current is a unique feature related to increasing glacial melt and precipitation on mainland Alaska.

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Signatur des Originals: S 36/F04850

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Signatur des Originals: S 36/F10577

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Signatur des Originals: S 36/F10578

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Signatur des Originals: S 36/F10551

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Signatur des Originals: S 36/F11977

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Signatur des Originals: S 36/F11978

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Purpose. To evaluate the presence of Community Associated–Methicillin Resistant Staphylococcus Aureus, CA-MRSA, in abscesses and skin and soft tissue infections presenting at 9 urgent care clinics in San Antonio, TX. ^ Methods. During the 40-month retrospective study (April 2006 to August 2009), wound cultures collected in 9 urgent care centers were evaluated for MRSA growth, antibiotics prescribed, follow up wound care, and antibiotic prescribing habits by physicians for all patients presenting with abscesses and skin/soft tissue infections. ^ Results. Across 9 urgent care centers in San Antonio, TX, 36,797 abscesses and cases of skin and soft tissue infections were treated during 40 months. Of the 36,797 cases, 9290 patients had wound cultures sent with 5,630 cultures sent to Texas MedClinic’s primary lab. Of the 5630 cultures sent to their primary lab, this reflected a prevalence of 4727 (84 %) cultures were positive for MRSA. Of the 9290 patients who had a wound culture sent (April 10th, 2006 to August 31st, 2009), a total of 4,307 antibiotics were prescribed. The top five antibiotics prescribed for CA-MRSA were Bactrim (55.5%), Clindamycin (18.4%), Bactroban (5%), Amoxicillin (3.5%), and Doxycycline (3%) representing 85.4% of the antibiotics prescribed. 8809/9290 (94.8%) of patients required no more than 3 follow up visits. Of the 33 physicians working full time during the entire study period, 29/33 (87.8%) of the physicians were family medicine physicians and represented varied prescribing rates of antibiotics between 11-76% with 26/33 (78.8%) of physicians prescribing antibiotics greater than 40% of the time.^ Conclusions. Abscesses and soft tissue infections are a common presenting complaint to urgent care centers. This study reveals that antibiotic-prescribing practices can be improved with physician education since this high prevalence was not known previously. Also, treating abscesses with limited packing has been shown to be a viable option in this particular circumstance and would be open field for additional clinical research. Due to the high prevalence of CA-MRSA skin and soft tissue infections among patients presenting to urgent care centers presumptive treatment for MRSA is indicated. Increasing levels of resistance to penicillin antibiotics is concerning and warrants alternative antibiotic management strategies.^

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Tropical south-western Pacific temperatures are of vital importance to the Great Barrier Reef (GBR), but the role of sea surface temperatures (SSTs) in the growth of the GBR since the Last Glacial Maximum remains largely unknown. Here we present records of Sr/Ca and d18O for Last Glacial Maximum and deglacial corals that show a considerably steeper meridional SST gradient than the present day in the central GBR. We find a 1-2 °C larger temperature decrease between 17° and 20°S about 20,000 to 13,000 years ago. The result is best explained by the northward expansion of cooler subtropical waters due to a weakening of the South Pacific gyre and East Australian Current. Our findings indicate that the GBR experienced substantial meridional temperature change during the last deglaciation, and serve to explain anomalous deglacial drying of northeastern Australia. Overall, the GBR developed through significant SST change and may be more resilient than previously thought.

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The early Late Pliocene (3.6 to ~3.0 million years ago) is the last extended interval in Earth's history when atmospheric CO2 concentrations were comparable to today's and global climate was warmer. Yet a severe global glaciation during marine isotope stage (MIS) M2 interrupted this phase of global warmth ~3.30 million years ago, and is seen as a premature attempt of the climate system to establish an ice-age world. Our geochemical and palynological records from five marine sediment cores along a Caribbean to eastern North Atlantic transect show that increased Pacific-to-Atlantic flow via the Central American Seaway weakened the North Atlantic Current (NAC) and attendant northward heat transport prior to MIS M2. The consequent cooling of the northern high latitude oceans permitted expansion of the Greenland ice sheet during MIS M2, despite near-modern atmospheric CO2 concentrations. Before and after MIS M2, heat transport via the NAC was crucial in maintaining warm climates comparable to those predicted for the end of this century.