Substrate induction and glucose repression of maltose utilization by Streptomyces coelicolor A3(2) is controlled by malR, a member of the lacI-galR family of regulatory genes

malR of Strepomyces coelicolor A3(2) encodes a homologue of the Lacl/Galr family of repressor proteins, and is divergently transcribed from the malEFG gene cluster, which encodes components of an ATP-dependent transport system that is required for maltose utilization. Transcription of malE was induced by maltose and repressed by glucose. Disruption or deletion of malR resulted in constitutive, glucose-insensitive malE transcription at a level markedly above that observed in the parental malR+ strain, and overproduction of MalR prevented growth on maltose as carbon source. Consequently, MalR plays a crucial role in both substrate induction and glucose repression of maltose utilization. MalR is expressed from a single promoter with transcription initiating at the first G of the predicted GTG translataion start codon

Symmetry is its own reward: on the character and significance of Acheulean handaxe symmetry in the Middle Pleistocene

Bilateral symmetry in handaxes has significant implications for hominin cognitive and socio-behavioural evolution. Here the authors show that high levels of symmetry occur in the British Late Middle Pleistocene Acheulean, which they consider to be a deliberate, socially mediated act. Furthermore, they argue that lithic technology in general, and handaxes in particular, were part of a pleasure-reward system linked to dopamine-releasing neurons in the brain. Making handaxes made Acheulean hominins happy, and one particularly pleasing property was symmetry

Case Study: Reporting Incidence of Severe Acute Respiratory Syndrome (SARS)

The SARS case is an in-depth study of the 2002-2003 global outbreak of Severe Acute Respiratory Syndrome (SARS). It focuses specifically on how information about the disease was shared among countries

Case Study: The EU-US Dispute over Regulation of Genetically Modified Organisms, Plants, Feeds, and Foods

The EU-US Dispute over Regulation of Genetically Modified Organisms, Plants, Feeds, and Foods case is a study of the divergence of regulatory standards for genetically modified plants, feeds, and food in the US and in European countries. It focuses on the European Union’s moratorium of approval of new genetically modified organisms and the World Trade Organization’s consequent ruling

Migration and the epidemiological transition: insights from the Agincourt sub-district of northeast South Africa

KIMBACKGROUND: Migration and urbanization are central to sustainable development and health, but data on temporal trends in defined populations are scarce. Healthy men and women migrate because opportunities for employment and betterment are not equally distributed geographically. The disruption can result in unhealthy exposures and environments and income returns for the origin household. OBJECTIVES: The objectives of the paper are to describe the patterns, levels, and trends of temporary migration in rural northeast South Africa; the mortality trends by cause category over the period 2000-2011; and the associations between temporary migration and mortality by broad cause of death categories. METHOD: Longitudinal, Agincourt Health and Demographic Surveillance System data are used in a continuous, survival time, competing-risk model. FINDINGS: In rural, northeast South Africa, temporary migration, which involves migrants relocating mainly for work purposes and remaining linked to the rural household, is more important than age and sex in explaining variations in mortality, whatever the cause. In this setting, the changing relationship between temporary migration and communicable disease mortality is primarily affected by reduced exposure of the migrant to unhealthy conditions. The study suggests that the changing relationship between temporary migration and non-communicable disease mortality is mainly affected by increased livelihood benefits of longer duration migration. CONCLUSION: Since temporary migration is not associated with communicable diseases only, public health policies should account for population mobility whatever the targeted health risk. There is a need to strengthen the rural health care system, because migrants tend to return to the rural households when they need health care

The use of uplift modelling in the reconstruction of drainage development and landscape evolution in the repeatedly glaciated Trent catchment, English Midlands, UK

The Trent Valley Palaeolithic Project has recently investigated the Quaternary evolution of the River Trent, the northernmost river system in western Europe with a documented long-timescale terrace staircase. The uppermost and lowermost reaches of the Trent, which drains the English Midlands, were glaciated during Marine oxygen Isotope Stage (MIS) 2, but older fluvial terraces dating back to MIS 8 are preserved in the remainder of the catchment, delineating the former course through the Lincoln Gap and across the Fen Basin (the modern course to the Humber estuary dating only from the latest Pleistocene). Numerical modelling enables lateral variations in uplift across the catchment to be deduced from differences in height of these fluvial terraces above the modern valley floor. Uplift rates thus indicated over the last two climate cycles attain values of ∼0.08 mm a−1 around Nottingham and Derby in the middle reach of the Trent, but are significantly lower elsewhere in the catchment; these variations are shown to relate to lateral variations in crustal properties, primarily variations in radioactive heat production in the underlying continental crust. Glaciation during the late Middle Pleistocene (MIS 8) caused significant changes to the Trent catchment, including the integration of the modern Upper Trent with the rest of the system. Older sedimentary evidence is much more fragmentary, but is used along with the results of the uplift modelling to reconstruct the earlier drainage. It is thus inferred that between the Anglian (MIS 12) and Wragby (MIS 8) glaciations the Trent already flowed into the Fen Basin via the Lincoln Gap, but the smaller-than-present catchment, indicated by gravel lithology, resulted in a much steeper longitudinal gradient, such that during interglacials (MIS 11 and 9) an elongated estuary would have developed, extending inland almost to the present location of Newark. Prior to the Anglian, much of the modern Trent catchment, including the rivers Derwent and Dove, drained into the former Bytham River. The modern Middle Trent catchment downstream of Nottingham was drained by a relatively small ‘Ancaster Trent’ river, which flowed above the Ancaster Gap; analysis of gravel lithology suggests that it probably joined the Bytham in the area that now forms the Fen Basin

Plate Fin Heat Exchanger Model with Axial Conduction and Variable Properties

Future superconducting radio frequency (SRF) cavities, as part of Project X at Fermilab, will be cooled to superfluid helium temperatures by a cryogenic distribution system supplying cold supercritical helium. To reduce vapor fraction during the final Joule-Thomson (J-T) expansion into the superfluid helium cooling bath, counter-flow, plate-fin heat exchangers will be utilized. Due to their compact size and ease of fabrication, plate-fin heat exchangers are an effective option. However, the design of compact and high-effectiveness cryogenic heat exchangers operating at liquid helium temperatures requires consideration of axial heat conduction along the direction of flow, in addition to variable fluid properties. Here we present a numerical model that includes the effects of axial conduction and variable properties for a plate fin heat exchanger. The model is used to guide design decisions on heat exchanger material choice and geometry. In addition, the J-T expansion process is modeled with the heat exchanger to analyze the effect of heat load and cryogenic supply parameters.Comment: 8 pp. Cryogenic Engineering Conference and International Cryogenic Materials Conference CEC-ICMC, 13-17 June 2011, Spokane, Washingto

An inverse method for estimating thickness and volume with time of a thin CO2-filled layer at the Sleipner Field, North Sea

Migration of CO 2 through storage reservoirs can be monitored using time lapse seismic reflection surveys. At the Sleipner Field, injected CO 2 is distributed throughout nine layers within the reservoir. These layers are too thin to be seismically resolvable by direct measurement of the separation between reflections from the top and bottom of each layer. Here we develop and apply an inverse method for measuring thick ness changes of the shallowest layer. Our approach combines differences in traveltime down to a specific reflection together with amplitude measurements to determine layer thicknesses from time lapse surveys. A series of synthetic forward models were used to test the robustness of our inverse approach and to quantify uncertainties. In the absence of ambient noise, this approach can unambiguously resolve layer thickness. If a realistic ambient noise distribution is included, layer thicknesses of 1–6 m are accurately retrieved with an uncertainty of ±0.5 m. We used this approach to generate a thickness map of the shallowest layer. The fidelity of this result was tested using measurements of layer thickness determined from the 2010 broadband seismic survey. The calculated volume of CO 2 within the shallowest layer increases at a rate that is quadratic in time, despite an approximately constant injection rate into the base of the reser voir. This result is consistent with a diminished growth rate of the areal extent of underlying layers. Finally, the relationship between caprock topography and layer thickness is explored and potential migration pathways that charge this layer are identified