The British Lower Palaeolithic of the early Middle Pleistocene

The archaeology of Britain during the early Middle Pleistocene (MIS 19–12) is represented by a number of key sites across eastern and southern England. These sites include Pakefield, Happisburgh 1, High Lodge, Warren Hill, Waverley Wood, Boxgrove, Kent's Cavern, and Westbury-sub-Mendip, alongside a ‘background scatter’ lithic record associated with the principal river systems (Bytham, pre-diversion Thames, and Solent) and raised beaches (Westbourne–Arundel). Hominin behaviour can be characterised in terms of: preferences for temperate or cool temperate climates and open/woodland mosaic habitats (indicated by mammalian fauna, mollusca, insects, and sediments); a biface-dominated material culture characterised by technological diversity, although with accompanying evidence for distinctive core and flake (Pakefield) and flake tool (High Lodge) assemblages; probable direct hunting-based subsistence strategies (with a focus upon large mammal fauna); and generally locally-focused spatial and landscape behaviours (principally indicated by raw material sources data), although with some evidence of dynamic, mobile and structured technological systems. The British data continues to support a ‘modified short chronology’ to the north of the Alps and the Pyrenees, with highly sporadic evidence for a hominin presence prior to 500–600 ka, although the ages of key assemblages are subject to ongoing debates regarding the chronology of the Bytham river terraces and the early Middle Pleistocene glaciations of East Anglia.

Turning points: the personal and professional circumstances that lead academics to become middle managers

In the current higher education climate, there is a growing perception that the pressures associated with being an academic middle manager outweigh the perceived rewards of the position. This article investigates the personal and professional circumstances that lead academics to become middle managers by drawing on data from life history interviews undertaken with 17 male and female department heads from a range of disciplines, in a post-1992 UK university. The data suggests that experiencing conflict between personal and professional identities, manifested through different socialization experiences over time, can lead to a ‘turning point’ and a decision that affects a person’s career trajectory. Although the results of this study cannot be generalized, the findings may help other individuals and institutions move towards a firmer understanding of the academic who becomes head of department—in relation to theory, practice and research.

Early–Middle Holocene vegetation history, climate change and human activities at Lago Riane (Ligurian Apennines, NW Italy)

The radiocarbon-dated palaeoecological study of Lago Riane (Ligurian Apennines, NW Italy) presented here forms part of a wider investigation into the relationships between Holocene vegetation succession, climate change and human activities in the northern Apennines. The record of vegetation history from Lago Riane indicates that, since the end of the last glaciation, climate change and prehistoric human activities, combined with several local factors, have strongly influenced the pattern and timing of natural vegetation succession. The pollen record indicates an important change in vegetation cover at Lago Riane at ~8500–8200 cal. years b.p., coincident with a well-known period of rapid climate change. At ~6100 cal. years b.p., Fagus woodland colonised Lago Riane during a period of climate change and expansion of Late Neolithic human activities in the upland zone of Liguria. A marked decline in Abies woodland, and the expansion of Fagus woodland, at ~4700 cal. years b.p., coincided with further archaeological evidence for pastoralism in the mountains of Liguria during the Copper Age. At ~3900–3600 cal. years b.p. (Early to Middle Bronze Age transition), a temporary expansion of woodland at Lago Riane has been provisionally attributed to a decline in human pressure on the environment during a period of short-term climate change

The history of entrepreneurship: Medieval origins of a modern phenomenon

The origins of enterprise are often associated with the Industrial Revolution, but this article presents evidence of entrepreneurial activities from a much earlier date – the medieval period. Between 1250 and 1500 the church, merchants and members of the royal court all engaged in activities that demonstrated the entrepreneurial characteristics of innovation, risk-taking and judgement. The activities of the prior of Tynemouth and the career of the wool merchant William de la Pole illustrate these developments. By focusing on individuals rather than firms, it is possible to push back the study of entrepreneurship beyond the Industrial Revolution and early-modern trade to a period that witnessed the origins of the modern state.

Forests of the tropical eastern Andean flank during the middle pleistocene

Inter-bedded volcanic and organic sediments from Erazo (Ecuador) indicate the presence of four different forest assemblages on the eastern Andean flank during the middle Pleistocene. Radiometric dates (40Ar–39Ar) obtained fromthe volcanic ash indicate that deposition occurred between 620,000 and 192,000 years ago. Examination of the organic sediment composition and the fossil pollen, wood and charcoal it contains provides insight into depositional environment, vegetation assemblage and fire history. The high organic content and abundance of macro fossils found throughout the sediment suggest that during the period of deposition the local environment was either a swamp or a shallow water body. The correlation of fire activity (peaks in charcoal abundance) with volcanic ash deposits through most of the record suggests that volcanoes were the main source of ignition. The low abundance of grass (typically b10%) throughout the sedimentary sequence along with the low abundance of other taxa indicative of open vegetation suggests the persistence of forest at Erazo. Four types of forest assemblage were identified (with the first taxa as the most dominant): i) Alnus-Arecaceae, ii) Miconia- Melastomataceae/Combretaceae-Moraceae/Urticaceae, iii) Arecaceae-Alnus, and iv) Podocarpus with Oreopanax sp. and Melastomataceae/Combretaceae. Changes in the forest floristic composition indicate high vegetation turnover and reassortment of taxa between upper and lower montane forests during the middle Pleistocene as well as the persistence of forest cover.

Late Würm and Early-Middle Holocene environmental change and human activities in the Northern Apennines, Italy

An enhanced radiocarbon-dated pollen-stratigraphical record from Rovegno (Liguria, 812m asl), northern Apennines (Italy), has provided a history of vegetation succession from before 17,056-16,621 cal yrs BP to the present day. The record indicates the transition from open Pinus woodland to Artemisia dominated grassland, and finally Juniperus shrubland during the late Würm. This is succeeded by Betula and Pinus woodland, and the expansion of thermophilous taxa, namely Abies, Corylus and Quercus during the Late Würm Lateglacial Interstadial. The ‘Younger Dryas’ is possibly represented by an increase in Betula and Artemisia. During the early Holocene, mixed coniferous-deciduous woodland is dominant with Quercus, as well as Abies, Fagus and Corylus. Fagus woodland becomes established sometime before 6488-6318 cal yrs BP, but never becomes a major component of the woodland cover. Throughout the middle Holocene, Abies woodland fl uctuates, with marked declines between 6488-6318 cal yrs BP and 5287-4835 cal yrs BP, although the cause remains uncertain. Finally, the paper evaluates the application of non-pollen palynomorphs, especially coprophilous fungal spores, at Prato Spilla ‘A’ (Emilia Romagna) and concludes that greater caution must be used when interpreting middle Holocene human activity based upon pollen data alone

Variability in life-history and ecological traits is a buffer against extinction in mammals

Anthropogenic degradation of the world's ecosystems is leading to a widespread and accelerating loss of biodiversity. However, not all species respond equally to existing threats, raising the question: what makes a species more vulnerable to extinction? We propose that higher intraspecific variability may reduce the risk of extinction, as different individuals and populations within a species may respond differently to occurring threats. Supporting this prediction, our results show that mammalian species with more variable adult body masses, litter sizes, sexual maturity ages and population densities are less vulnerable to extinction. Our findings reveal the role of local variation among populations, particularly of large mammals, as a buffering mechanism against extinction, and emphasise the importance of considering trait variation in comparative analyses and conservation management.

Climate variability and socio-environmental changes in the northern Aegean (NE Mediterranean) during the last 1500 years

We provide new evidence on sea surface temperature (SST) variations and paleoceanographic/paleoenvironmental changes over the past 1500 years for the north Aegean Sea (NE Mediterranean). The reconstructions are based on multiproxy analyses, obtained from the high resolution (decadal to multidecadal) marine record M2 retrieved from the Athos basin. Reconstructed SSTs show an increase from ca. 850 to 950 AD and from ca. 1100 to 1300 AD. A cooling phase of almost 1.5 �C is observed from ca. 1600 AD to 1700 AD. This seems to have been the starting point of a continuous SST warming trend until the end of the reconstructed period, interrupted by two prominent cooling events at 1832 ± 15 AD and 1995 ± 1 AD. Application of an adaptive Kernel smoothing suggests that the current warming in the reconstructed SSTs of the north Aegean might be unprecedented in the context of the past 1500 years. Internal variability in atmospheric/oceanic circulations systems as well as external forcing as solar radiation and volcanic activity could have affected temperature variations in the north Aegean Sea over the past 1500 years. The marked temperature drop of approximately ~2 �C at 1832 ± 15 yr AD could be related to the 1809 АD ‘unknown’ and the 1815 AD Tambora volcanic eruptions. Paleoenvironmental proxy-indices of the M2 record show enhanced riverine/continental inputs in the northern Aegean after ca. 1450 AD. The paleoclimatic evidence derived from the M2 record is combined with a socio-environmental study of the history of the north Aegean region. We show that the cultivation of temperature-sensitive crops, i.e. walnut, vine and olive, co-occurred with stable and warmer temperatures, while its end coincided with a significant episode of cooler temperatures. Periods of agricultural growth in Macedonia coincide with periods of warmer and more stable SSTs, but further exploration is required in order to identify the causal links behind the observed phenomena. The Black Death likely caused major changes in agricultural activity in the north Aegean region, as reflected in the pollen data from land sites of Macedonia and the M2 proxy-reconstructions. Finally, we conclude that the early modern peaks in mountain vegetation in the Rhodope and Macedonia highlands, visible also in the M2 record, were very likely climate-driven.

Araucaria forest dynamics in relation to fire frequency in southern Brazil based on fossil and modern pollen dataf

To elucidate the relationship between forest dynamics and fire frequency pollen percentages and charcoal amounts from a 120 cm long peat core and from samples of modern pollen rain were collected along a transect. The study site in southern Brazil is characterized by a species-rich mosaic of grassland-Araucaria forest. It is of crucial importance for management strategies for conservation to understand the development and maintenance of these vegetation mosaics including their sharp forest-grassland boundaries. During the late Holocene, considerable changes occurred in the area. From Anno Domini (AD) 1360 to 1410, the area was dominated by Campos (grassland) vegetation and fire was very common. From AD 1410 to 1500, Araucaria forest expanded and fire was less frequent. From AD 1500 to 1580, Campos grassland spread and the Araucaria forest ceased its development, apparently due to the increase of fire. From AD 1580 to 1935, after a decrease in fire frequency, Araucaria forest expanded again. From AD 1935 to the present, the Araucaria forest expanded while the Campos area decreased. Fire was very rare in this period. The results indicate a strong interaction of forest expansion, forming a mosaic of Campos and Araucaria forest, and the frequency of fire during the past 600 years. A possible collapse of the indigenous population following the post-Colombian colonization in southern Brazil after about AD 1550 may have caused a great reduction of fire frequency. The introduction of cattle (probably after AD 1780) and the resulting decrease of fire frequency might be the reason for forest expansion. Fire is probably the most important factor controlling the dynamics of the forest-grassland mosaics and the formation of sharp borders between these two vegetation types. (C) 2010 Elsevier B.V. All rights reserved.

Evolutionary history of Ramphastos toucans: Molecular phylogenetics, temporal diversification, and biogeography

The toucan genus Ramphastos (Piciformes: Ramphastidae) has been a model in the formulation of Neotropical paleobiogeographic hypotheses. Weckstein (2005) reported on the phylogenetic history of this genus based on three mitochondrial genes, but some relationships were weakly supported and one of the subspecies of R. vitellinus (citreolaemus) was unsampled. This study expands on Weckstein (2005) by adding more DNA sequence data (including a nuclear marker) and more samples, including R v. citreolaemus. Maximum parsimony, maximum likelihood, and Bayesian methods recovered similar trees, with nodes showing high support. A monophyletic R. vitellinus complex was strongly supported as the sister-group to R. brevis. The results also confirmed that the southeastern and northern populations of R. vitellinus ariel are paraphyletic. X v. citreolaemus is sister to the Amazonian subspecies of the vitellinus complex. Using three protein-coding genes (COI, cytochrome-b and ND2) and interval-calibrated nodes under a Bayesian relaxed-clock framework, we infer that ramphastid genera originated in the middle Miocene to early Pliocene, Ramphastos species originated between late Miocene and early Pleistocene, and intra-specific divergences took place throughout the Pleistocene. Parsimony-based reconstruction of ancestral areas indicated that evolution of the four trans-Andean Ramphastos taxa (R. v. citreolaemus, R. a. swainsonii, R. brevis and R. sulfuratus) was associated with four independent dispersals from the cis-Andean region. The last pulse of Andean uplift may have been important for the evolution of R. sulfuratus, whereas the origin of the other trans-Andean Ramphastos taxa is consistent with vicariance due to drying events in the lowland forests north of the Andes. Estimated rates of molecular evolution were higher than the ""standard"" bird rate of 2% substitutions/site/million years for two of the three genes analyzed (cytochrome-b and ND2). (C) 2009 Elsevier Inc. All rights reserved.

Phylogeography and evolutionary history of dengue virus type 3

In this study, we revisited the phylogeography of the three of major DENV-3 genotypes and estimated its rate of evolution, based on the analysis of the envelope (E) gene of 200 strains isolated from 31 different countries around the world over a time period of 50 years (1956-2006). Our phylogenetic analysis revealed a geographical subdivision of DENV-3 population in several country-specific clades. Migration patterns of the main DENV-3 genotypes showed that genotype I was mainly circumspect to the maritime portion of Southeast-Asia and South Pacific, genotype 11 stayed within continental areas in South-East Asia, while genotype III spread across Asia, East Africa and into the Americas. No evidence for rampant co-circulation of distinct genotypes in a single locality was found, suggesting that some factors, other than geographic proximity, may limit the continual dispersion and reintroduction of new DENV-3 variants. Estimates of the evolutionary rate revealed no significant differences among major DENV-3 genotypes. The mean evolutionary rate of DENV-3 in areas with long-term endemic transmissions (i.e., Indonesia and Thailand) was similar to that observed in the Americas, which have been experiencing a more recent dengue spread. We estimated the origin of DENV-3 virus around 1890, and the emergence of current diversity of main DENV-3 genotypes between the middle 1960s and the middle 1970s, coinciding with human population growth, urbanization, and massive human movement, and with the description of the first cases of DENV-3 hemorrhagic fever in Asia. (C) 2008 Elsevier B.V. All rights reserved.

Precambrian history of the Zona Transversal of the Borborema Province, NE Brazil: Insights from Sm-Nd and U-Pb geochronology

The Borborema Province has three major subprovinces. The northern subprovince lies north of the Patos shear zone and is comprised of Paleoproterozoic cratonic basement with Archean nuclei, plus overlying Neoproterozoic supracrustal rocks and Brasiliano plutonic rocks. The central subprovince occurs between the Patos and Pernambuco shear zones and is mainly comprised of the Zona Transversal. The southern subprovince occurs between the Pernamabuco shear zone and the Sao Francisco craton and is comprised of a tectonic collage of various blocks, terranes, or domains ranging in age from Archean to Neoproterozoic. This report focuses on the Zona Transversal, especially on Brasiliano rocks for which we have the most new information. Paleoproterozoic gneisses with ages of 2.0-2.2 Ga occur discontinuously throughout the Zona Transversal. The Cariris Velhos suite consists of metavolcanic, metasedimentary, and metaplutonic rocks yielding U-Pb zircon ages of 995-960 Ma. This suite is mainly confined to a 100 km wide belt that extends for more than 700 km within the Alto Pajeu terrane. Sm-Nd model ages in metaigneous rocks cluster about 1.3-1.6 Ga, indicating that older crust was involved in genesis of their magmas. Brasiliano supracrustal rocks dominate the Pianco-Alto Brigida terrane, and they probably also constitute significant parts of the Alto Pajeu and Rio Capibaribe terranes. They are only slightly older than early stages of Brasiliano plutonism, with detrital zircon ages at least as young as 620 Ma; most T(DM) ages range from 1.2 to 1.6 Ga. Brasiliano plutons range from ca. 640 to 540 Ma, and their T(DM) ages range from 1.2 to 2.5 Ga. Previous workers have shown significant correlations among U-Pb ages, Sm-Nd model ages, petrology, and geochemistry, and we are able to reinforce and extend these correlations. Stage I plutons formed 640 -610 Ma and have T(DM) ages less than 1.5 Ga. Stage 11 (610-590 Ma) contains few plutons, but coincides with the peak of compressional deformation, metamorphism, and formation of migmatites. Stage III plutons (590 to ca. 575 Ma) have older T(DM) ages (ca. 1.8-2.0 Ga), as do Stage IV plutons (575 to ca. 550 Ma; T(DM) from 1.9 to 2.4 Ga). Stage III plutons formed during the transition from compressional to transcurrent deformation, while Stage IV plutons are mainly post-tectonic. Stage V plutons (550-530 Ma) are commonly undeformed (except along younger shear zones) and have A-type geochemistry. The five stages have distinct geochemical properties, which suggest that the tectonic settings evolved from early, arc-related magma-genesis (Stage I) to within-plate magma-genesis (Stage V), with perhaps some intermediate phases of extensional environments. (C) 2011 Elsevier Ltd. All rights reserved.

High T/P evolution and metamorphic ages of the migmatitic basement of northern Sierras Pampeanas, Argentina: Characterization of a mid-crustal segment of the Famatinian belt

New petrologic, thermobarometric and U-Pb monazite geochronologic information allowed to resolve the metamorphic evolution of a high temperature mid-crustal segment of an ancient subduction-related orogen. The EI Portezuelo Metamorphic-Igneous Complex, in the northern Sierras Pampeanas, is mainly composed of migmatites that evolved from amphibolite to granulite metamorphic facies, reaching thermal peak conditions of 670-820 degrees C and 4.5-5.3 kbar. The petrographic study combined with conventional and pseudosection thermobarometry led to deducing a short prograde metamorphic evolution within migmatite blocks. The garnet-absent migmatites represent amphibolite-facies rocks, whereas the cordierite-garnet-K-feldspar-sillimanite migmatites represent higher metamorphic grade rocks. U-Pb geochronology on monazite grains within leucosome record the time of migmatization between approximate to 477 and 470 Ma. Thus, the El Portezuelo Metamorphic-Igneous Complex is an example of exhumed Early Ordovician anatectic middle crust of the Famatinian mobile belt. Homogeneous exposure of similar paleo-depths throughout the Famatinian back-arc and isobaric cooling paths suggest slow exhumation and consequent longstanding crustal residence at high temperatures. High thermal gradients uniformly distributed in the Famatinian back-arc can be explained by shallow convection of a low-viscosity asthenosphere promoted by subducting-slab dehydration. (C) 2011 Elsevier Ltd. All rights reserved.