Discover the most talked about and latest scientific content & concepts.

Concept: Centuries


We assess the relationship between temperature and global sea-level (GSL) variability over the Common Era through a statistical metaanalysis of proxy relative sea-level reconstructions and tide-gauge data. GSL rose at 0.1 ± 0.1 mm/y (2σ) over 0-700 CE. A GSL fall of 0.2 ± 0.2 mm/y over 1000-1400 CE is associated with ∼0.2 °C global mean cooling. A significant GSL acceleration began in the 19th century and yielded a 20th century rise that is extremely likely (probability [Formula: see text]) faster than during any of the previous 27 centuries. A semiempirical model calibrated against the GSL reconstruction indicates that, in the absence of anthropogenic climate change, it is extremely likely ([Formula: see text]) that 20th century GSL would have risen by less than 51% of the observed [Formula: see text] cm. The new semiempirical model largely reconciles previous differences between semiempirical 21st century GSL projections and the process model-based projections summarized in the Intergovernmental Panel on Climate Change’s Fifth Assessment Report.

Concepts: Statistics, Climate change, 20th century, 21st century, Centuries, Intergovernmental Panel on Climate Change, Global warming, 19th century


Although research on human-mediated exchanges of species has substantially intensified during the last centuries, we know surprisingly little about temporal dynamics of alien species accumulations across regions and taxa. Using a novel database of 45,813 first records of 16,926 established alien species, we show that the annual rate of first records worldwide has increased during the last 200 years, with 37% of all first records reported most recently (1970-2014). Inter-continental and inter-taxonomic variation can be largely attributed to the diaspora of European settlers in the nineteenth century and to the acceleration in trade in the twentieth century. For all taxonomic groups, the increase in numbers of alien species does not show any sign of saturation and most taxa even show increases in the rate of first records over time. This highlights that past efforts to mitigate invasions have not been effective enough to keep up with increasing globalization.

Concepts: Time, Human migration, Taxonomic rank, Centuries, Alpha taxonomy


Medical confidentiality has come under attack in the public sphere. In recent disasters both journalists and politicians have questioned medical confidentiality and claimed that in specific contexts physicians should be compelled to communicate data on their patients' health. The murders of innocent individuals by a suicidal pilot and a Swiss convicted criminal have generated polemical debates on the topic. In this article, historical data on medical confidentiality is used to show that medical practices of secrecy were regularly attacked in the past, and that the nature of medical confidentiality evolved through time depending on physicians' values and judgements. Our demonstration is based on three moments in history. First, at the end of the 16th century, lay authorities put pressure on physicians to disclose the names of patients suffering from syphilis. Second, in the 18th century, physicians faced constant demands for information about patients' health from relatives and friends. Third, employers and insurance companies in the 20th century requested medical data on sick employees. In these three different situations, history reveals that the concept of medical confidentiality was plastic, modelled in the first instance to defend well-to-do patients, in the second instance it was adapted to accommodate the physician’s social role and, finally, to defend universal values and public health. Medical secrecy was, and is today, a medical and societal norm that is shaped collectively. Any change in its definition and enforcement was and should be the result of negotiations with all social actors concerned.

Concepts: Medicine, Sociology, Physician, Centuries, 18th century, Confidentiality, 2nd millennium, 16th century


The review article attempts to focus on the practice of human cadaveric dissection during its inception in ancient Greece in 3rd century BC, revival in medieval Italy at the beginning of 14th century and subsequent evolution in Europe and the United States of America over the centuries. The article highlights on the gradual change in attitude of religious authorities towards human dissection, the shift in the practice of human dissection being performed by barber surgeons to the anatomist himself dissecting the human body and the enactment of prominent legislations which proved to be crucial milestones during the course of the history of human cadaveric dissection. It particularly emphasizes on the different means of procuring human bodies which changed over the centuries in accordance with the increasing demand due to the rise in popularity of human dissection as a tool for teaching anatomy. Finally, it documents the rise of body donation programs as the source of human cadavers for anatomical dissection from the second half of the 20th century. Presently innovative measures are being introduced within the body donation programs by medical schools across the world to sensitize medical students such that they maintain a respectful, compassionate and empathetic attitude towards the human cadaver while dissecting the same. Human dissection is indispensable for a sound knowledge in anatomy which can ensure safe as well as efficient clinical practice and the human dissection lab could possibly be the ideal place to cultivate humanistic qualities among future physicians in the 21st century.

Concepts: Biology, United States, Human body, Anatomy, Human anatomy, Centuries, Cadaver, Dissection


An annually resolved and absolutely dated ring-width chronology spanning 4,500 y has been constructed using subfossil, archaeological, and living-tree juniper samples from the northeastern Tibetan Plateau. The chronology represents changing mean annual precipitation and is most reliable after 1500 B.C. Reconstructed precipitation for this period displays a trend toward more moist conditions: the last 10-, 25-, and 50-y periods all appear to be the wettest in at least three and a half millennia. Notable historical dry periods occurred in the 4th century BCE and in the second half of the 15th century CE. The driest individual year reconstructed (since 1500 B.C.) is 1048 B.C., whereas the wettest is 2010. Precipitation variability in this region appears not to be associated with inferred changes in Asian monsoon intensity during recent millennia. The chronology displays a statistical association with the multidecadal and longer-term variability of reconstructed mean Northern Hemisphere temperatures over the last two millennia. This suggests that any further large-scale warming might be associated with even greater moisture supply in this region.

Concepts: Chronology, Precipitation, Climate, Tropical cyclone, Centuries, Monsoon, Global warming, Anno Domini


Although endogenous retroviruses are common across vertebrate genomes, the koala retrovirus (KoRV) is the only retrovirus known to be currently invading the germ line of its host. KoRV is believed to have first infected koalas in northern Australia less than two centuries ago. We examined KoRV in 28 koala museum skins collected in the late 19th and 20th centuries and deep sequenced the complete proviral envelope region from five northern Australian specimens. Strikingly, KoRV env sequences were conserved among koalas collected over the span of a century, and two functional motifs that affect viral infectivity were fixed across the museum koala specimens. We detected only 20 env polymorphisms among the koalas, likely representing derived mutations subject to purifying selection. Among northern Australian koalas, KoRV was already ubiquitous by the late 19th century, suggesting that KoRV evolved and spread among koala populations more slowly than previously believed. Given that museum and modern koalas share nearly identical KoRV sequences, it is likely that koala populations, for more than a century, have experienced increased susceptibility to diseases caused by viral pathogenesis.

Concepts: DNA, Natural selection, Molecular biology, Australia, Retrovirus, Centuries, 19th century, Koala


From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain’s gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries.

Concepts: Europe, Western Europe, Centuries, Neolithic, Bronze Age, Beaker culture, Megalith, Wessex culture


Episodes of population loss and cultural change, including the famous Classic Collapse, punctuated the long course of Maya civilization. In many cases, these downturns in the fortunes of individual sites and entire regions included significant environmental components such as droughts or anthropogenic environmental degradation. Some afflicted areas remained depopulated for long periods, whereas others recovered more quickly. We examine the dynamics of growth and decline in several areas in the Maya Lowlands in terms of both environmental and cultural resilience and with a focus on downturns that occurred in the Terminal Preclassic (second century Common Era) and Terminal Classic (9th and 10th centuries CE) periods. This examination of available data indicates that the elevated interior areas of the Yucatán Peninsula were more susceptible to system collapse and less suitable for resilient recovery than adjacent lower-lying areas.

Concepts: Maya civilization, Maya peoples, Culture, The Terminal, Centuries, Civilization, Societal collapse, The Fortunes


A total of nine tin-contained ancient glass beads were characterized by a combination of scanning electron microscopy coupled with energy-dispersive X-ray spectrometry and Raman spectroscopy. These glass beads dated from 1st century BC to 10th century AD were excavated from the Xinjiang and Guangxi provinces of China. Two kinds of tin-based opacifiers/colorants included crystalline cassiterite (SnO(2) ) and lead-tin yellow types II were first found in these soda lime glass beads. The tentative chronology of the tin-based opacifiers/colorants used in ancient glasses from China and the West was compared. In addition, several transition metal ions colorants were also found in these beads. The detailed study of the glassy matrices, crystalline inclusions, and the microstructural heterogeneities for these glass beads has revealed some valuable information to trace the possible making technology and provenances. Microsc. Res. Tech., 2013. © 2012 Wiley Periodicals, Inc.

Concepts: Electron, Spectroscopy, Iron, Solid, Glass, Transition metal, Centuries, Soda-lime glass


The Bene Israel Jewish community from West India is a unique population whose history before the 18th century remains largely unknown. Bene Israel members consider themselves as descendants of Jews, yet the identity of Jewish ancestors and their arrival time to India are unknown, with speculations on arrival time varying between the 8th century BCE and the 6th century CE. Here, we characterize the genetic history of Bene Israel by collecting and genotyping 18 Bene Israel individuals. Combining with 486 individuals from 41 other Jewish, Indian and Pakistani populations, and additional individuals from worldwide populations, we conducted comprehensive genome-wide analyses based on FST, principal component analysis, ADMIXTURE, identity-by-descent sharing, admixture linkage disequilibrium decay, haplotype sharing and allele sharing autocorrelation decay, as well as contrasted patterns between the X chromosome and the autosomes. The genetics of Bene Israel individuals resemble local Indian populations, while at the same time constituting a clearly separated and unique population in India. They are unique among Indian and Pakistani populations we analyzed in sharing considerable genetic ancestry with other Jewish populations. Putting together the results from all analyses point to Bene Israel being an admixed population with both Jewish and Indian ancestry, with the genetic contribution of each of these ancestral populations being substantial. The admixture took place in the last millennium, about 19-33 generations ago. It involved Middle-Eastern Jews and was sex-biased, with more male Jewish and local female contribution. It was followed by a population bottleneck and high endogamy, which can lead to increased prevalence of recessive diseases in this population. This study provides an example of how genetic analysis advances our knowledge of human history in cases where other disciplines lack the relevant data to do so.

Concepts: Gene, Population genetics, Israel, Jews, Judaism, Centuries, Hungary, Ashkenazi Jews