A 14C age calibration curve for the last 60 ka: the Greenland-Hulu U/Th timescale and its impact on understanding the Middle to Upper Paleolithic transition in Western Eurasia.
This paper combines the data sets available today for 14C-age calibration of the last 60 ka. By stepwise synchronization of paleoclimate signatures, each of these sets of 14C-ages is compared with the U/Th-dated Chinese Hulu Cave speleothem records, which shows global paleoclimate change in high temporal resolution. By this synchronization we have established an absolute-dated Greenland-Hulu chronological framework, against which global paleoclimate data can be referenced, extending the 14C-age calibration curve back to the limits of the radiocarbon method. Based on this new, U/Th-based Greenland(Hulu) chronology, we confirm that the radiocarbon timescale underestimates calendar ages by several thousand years during most of Oxygen Isotope Stage 3. Major atmospheric 14C variations are observed for the period of the Middle to Upper Paleolithic transition, which has significant implications for dating the demise of the last Neandertals. The early part of "the transition" (with 14C ages > 35.0 ka 14C BP) coincides with the Laschamp geomagnetic excursion. This period is characterized by highly-elevated atmospheric 14C levels. The following period ca. 35.0-32.5 ka 14C BP shows a series of distinct large-scale 14C age inversions and extended plateaus. In consequence, individual archaeological 14C dates older than 35.0 ka 14C BP can be age-calibrated with relatively high precision, while individual dates in the interval 35.0-32.5 ka 14C BP are subject to large systematic age-'distortions,' and chronologies based on large data sets will show apparent age-overlaps of up to ca. 5,000 cal years. Nevertheless, the observed variations in past 14C levels are not as extreme as previously proposed ("Middle to Upper Paleolithic dating anomaly"), and the new chronological framework leaves ample room for application of radiocarbon dating in the age-range 45.0-25.0 ka 14C BP at high temporal resolution.
The purpose of this annotated chronology is to help provide a framework for research into the history of the first five years of the AIDS epidemic in Canada but especially as it unfolded in Toronto, Canada. The chronological entries can be used to identify the order and relationship of particular themes, while the sources listed in the chronology can be used as points of reference for further investigations. This chronology is primarily derived from reports in key newspapers based in the Toronto region. Each chronological entry lists the sources which reported on the particular event.
Filicide is the tragic crime of murdering one's own child. Previous research has found that the offending parents are commonly depressed and that suicide is often associated as an actual act or an intention. Yet, filicide is an underreported crime and previous studies have been strained with methodological problems. No comprehensive international studies on filicide have been presented in the literature until now.
This was a descriptive, comprehensive, register-based study of all filicides in Austria and Finland during 1995-2005. Filicide-suicide cases were also included.
Most of the perpetrators were the biological mothers; in Austria 72%, in Finland 52%. Suicide followed filicide either as an attempt or a fulfilled act in 32% and 54% of the cases in Austria and Finland, respectively. Psychotic mood disorders were diagnosed for 10% of the living perpetrators in Austria, and 12% in Finland. Non-psychotic depression was diagnosed in 9% of surviving perpetrators in Austria, 35% in Finland.
The data from the two countries demonstrated that filicide is such a multifaceted and rare phenomenon that national data from individual countries seldom offer sufficient scope for its thorough study. Further analyses are needed to produce a complete picture of filicide.
Severe acute respiratory syndrome (SARS) is a condition of unknown cause that has recently been recognized in patients in Asia, North America, and Europe. This report summarizes the initial epidemiologic findings, clinical description, and diagnostic findings that followed the identification of SARS in Canada.
SARS was first identified in Canada in early March 2003. We collected epidemiologic, clinical, and diagnostic data from each of the first 10 cases prospectively as they were identified. Specimens from all cases were sent to local, provincial, national, and international laboratories for studies to identify an etiologic agent.
The patients ranged from 24 to 78 years old; 60 percent were men. Transmission occurred only after close contact. The most common presenting symptoms were fever (in 100 percent of cases) and malaise (in 70 percent), followed by nonproductive cough (in 100 percent) and dyspnea (in 80 percent) associated with infiltrates on chest radiography (in 100 percent). Lymphopenia (in 89 percent of those for whom data were available), elevated lactate dehydrogenase levels (in 80 percent), elevated aspartate aminotransferase levels (in 78 percent), and elevated creatinine kinase levels (in 56 percent) were common. Empirical therapy most commonly included antibiotics, oseltamivir, and intravenous ribavirin. Mechanical ventilation was required in five patients. Three patients died, and five have had clinical improvement. The results of laboratory investigations were negative or not clinically significant except for the amplification of human metapneumovirus from respiratory specimens from five of nine patients and the isolation and amplification of a novel coronavirus from five of nine patients. In four cases both pathogens were isolated.
SARS is a condition associated with substantial morbidity and mortality. It appears to be of viral origin, with patterns suggesting droplet or contact transmission. The role of human metapneumovirus, a novel coronavirus, or both requires further investigation.
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Comment In: N Engl J Med. 2003 Aug 14;349(7):709-11; author reply 709-1112917312
Comment In: N Engl J Med. 2003 May 15;348(20):1948-5112748314
Center of Bio-Archaeology and Ecology (UMR5059 CNRS/USTL/EPHE), Institut de Botanique, 163 rue Broussonet, F-34090 Montpellier, France. carcaillet@univ-montp2.fr
Knowledge of past fire regimes is crucial for understanding the changes in fire frequency that are likely to occur during the coming decades as a result of global warming and land-use change. This is a key issue for the sustainable management of forest biodiversity because fire regimes may be controlled by vegetation, human activities, and/or climate. The present paper aims to reconstruct the pattern of fire frequency over the Holocene at three sites located in the same region in the northern Swedish boreal forest. The fire regime is reconstructed from sedimentary charcoal analysis of small lakes or ponds. This method allows fire events to be characterized, after detrending the charcoal influx series, and allows estimation of the time elapsed between fires. The long-term fire regime, in terms of fire-free intervals, can thus be elucidated. At the three sites, the mean fire-free intervals through the Holocene were long and of similar magnitude (approximately 320 years). This similarity suggests that the ecological processes controlling fire ignition and spread were the same. At the three sites, the intervals were shorter before 8600 cal yr BP (calibrated years before present), between 7500 and 4500 cal yr BP, and after 2500 cal yr BP. Geomorphological and vegetation factors cannot explain the observed change, because the three sites are located in the same large ecological region characterized by Pinus sylvestris-Ericaceae mesic forests, established on morainic deposits at the same elevation. Archaeological chronologies also do not match the fire chronologies. A climatic interpretation is therefore the most likely explanation of the long-term regional pattern of fire. Although recent human activities between the 18th and the 20th centuries have clearly affected the fire regime, the dominant factor controlling it for 10000 years in northern Sweden has probably been climatic.
One of the complications associated with insertion of central venous catheters (CVCs) is pneumothorax (PTX). Because of housestaff inexperience, it was hypothesised that rates of PTX after insertion of CVCs in teaching hospitals would be highest in July and August and in the first week of the month (beginning of intensive care unit (ICU) rotation).
In a retrospective analysis of data from patients admitted to the ICU in two tertiary care teaching hospitals in British Columbia from 1999 to 2005, rates of PTX occurring after insertion of CVCs were calculated, and it was evaluated whether rates were increased during certain times of the year/month.
During this period, 3548 patients were admitted to these ICUs and had at least one CVC placed. 5816 CVCs were inserted; 113 PTX occurred within 2 days after insertions (1.9% per CVC). The rate during the last week of the month was greater (2.7%) than during the first, second or third weeks (1.7%, 1.8% and 1.4%, respectively). This effect persisted after controlling for the Acute Physiology and Chronic Health Evaluation II score, the number of catheters placed per patient, gender, age and hospital. Rates of PTX after catheter placement did not vary by the month of the year.
The rate of PTX after insertion of CVCs is greatest in the last week of the month. If this effect can be verified in other centres, increased supervision of residents at the end of ICU rotations when placing CVCs should be considered. Whether this effect applies to other patient safety outcomes in the ICU also needs further study.
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