The Bottom Rung of the Ladder: Battlefield Nuclear Weapons in Europe

A war in Europe would pit the heavily armored forces of the Warsaw Pact (WP) against the far more lightly equipped North Atlantic Treaty Organization (Nato) defenses. The Nato forces can expect to find themselves outnumbered and outgunned by those of the Pact

Geology and Stratigraphy of the Western Kentucky Coal Field

The Pennsylvanian rocks of the Western Kentucky Coal Field produce between 40 and 55 million tons of coal a year from as many as 45 coal seams; however, three seams produce more than 75 percent of the total. In addition, Pennsylvanian strata contain numerous oil and natural gas reservoirs, tar-sand reservoirs, and industrial minerals. Pennsylvanian sandstones are also some of the most important bedrock aquifers in the coal field. Because of the economic importance of the Pennsylvanian strata to the region and the Commonwealth as a whole, a better understanding of these rocks is needed. This description of the nomenclature of Pennsylvanian strata in the Western Kentucky Coal Field also provides information on their mineral resources and geology. New stratigraphic names, based on regional agreements among the state geological surveys of Kentucky, Illinois, and Indiana, are also presented

Integrated Remote Sensing, Structural and Petroleum Systems Modeling of the Iraqi‐Kurdish Fold Belt

An integrated two‐dimensional remote sensing, structural and petroleum systems modeling study was carried out for the Iraqi‐Kurdish Fold Belt to analyze potential trap structures as well as the driving mechanisms of petroleum generation, migration and accumulation in the structural complex thrust belt area. Processing of Landsat‐7 ETM data has been used to create false color images, highlighting lithological differences, from which geological maps can be generated. Analysis of lineaments in these images is used to generate fault and fracture maps, producing a suite of geological surface maps. In addition, analysis of drainage patterns and erosional features is used to understand the relative age of the structures. Key regions were selected for ground‐truthing. Lastly, these maps were combined with published and proprietary subsurface data to create a structural cross‐section of the Qara Chauq to Bina Bawi transect of the Kurdish Folded Belt. The cross‐section indicates that a minimum of 20% shortening has occurred across this region. Twelve paleo‐sections, including pre‐ and post erosion geometries, were used for the model building process. The model features both, basement faults and surface folds as well as thrust geometries that accommodate the structural framework and its development. The strata were modeled as an alternating limestone and shale sequence. The Sargelu and the Kurra Chine Fm were considered as source rock intervals. The reservoir rocks include the Shiranish, Aqra‐Bekhme and the Sargelu Fm. The Gercus Fm acts as a regional seal horizon. Special focus was laid on the N‐S trending basement faults and their evolution through time since these faults appear to divide the petroleum system into areas of differing maturity. The influence of fault permeability evolution upon petroleum migration has been evaluated to unfold the charge history of the region. Temperature and vitrinite reflectance data derived from key wells and literature have been used for thermal calibration. The model results and a detailed petroleum systems analysis show the differential maturation and generation behavior of the source rock compartments and reveal the major influence of timing and fault migration for the oil & gas charge over time

Differential Forms on Log Canonical Spaces

The present paper is concerned with differential forms on log canonical varieties. It is shown that any p-form defined on the smooth locus of a variety with canonical or klt singularities extends regularly to any resolution of singularities. In fact, a much more general theorem for log canonical pairs is established. The proof relies on vanishing theorems for log canonical varieties and on methods of the minimal model program. In addition, a theory of differential forms on dlt pairs is developed. It is shown that many of the fundamental theorems and techniques known for sheaves of logarithmic differentials on smooth varieties also hold in the dlt setting. Immediate applications include the existence of a pull-back map for reflexive differentials, generalisations of Bogomolov-Sommese type vanishing results, and a positive answer to the Lipman-Zariski conjecture for klt spaces.Comment: 72 pages, 6 figures. A shortened version of this paper has appeared in Publications math\'ematiques de l'IH\'ES. The final publication is available at http://www.springerlink.co

Motor Qualification for Long-Duration Mars Missions

Qualification of motors for deep space under extreme thermal environments to be encountered during the Mars Science Laboratory (MSL) mission is required to verify the reliability and validate mission assurance requirements. The motor assembly must survive all ground operations, plus the nominal 670 Martian-day (or sol) mission that includes summer and winter seasons of the Mars environment. The motor assembly was tested and characterized under extreme temperature conditions with reference to hardware requirements. The motor assembly has been proved to be remarkably robust and displayed no sign of degradation due to the 3 X (three times per JPL design principles) thermal environmental exposure to the punishing Mars surface operations cycles. The motor characteristics obtained before, during, and post-test comparisons for the surface operations cycles are within measurement error of one another. The motors withstood/survived 2,010 extreme temperature cycles with a Delta T of 190 C deep temperature cycles, representing three times the expected thermal cycling exposure during the MSL surface operations. The qualification test hardware elements (A200 motor assembly, encoders, and resolver) have not shown any signs of degradation due to the PQV (Package Qualification and Verification) testing. The test hardware has demonstrated sufficient life to survive the deep thermal cycles associated with MSL mission surface operations for three lives

Slope and amplitude asymmetry effects on low frequency capacitively coupled carbon tetrafluoride plasmas

We report investigations of capacitively coupled carbon tetrafluoride (CF4) plasmas excited with tailored voltage waveforms containing up to five harmonics of a base frequency of 5.5 MHz. The impact of both the slope asymmetry, and the amplitude asymmetry, of these waveforms on the discharge is examined by combining experiments with particle-in-cell simulations. For all conditions studied herein, the discharge is shown to operate in the drift-ambipolar mode, where a comparatively large electric field in the plasma bulk (outside the sheaths) is the main mechanism for electron power absorption leading to ionization. We show that both types of waveform asymmetries strongly influence the ion energy at the electrodes, with the particularity of having the highest ion flux on the electrode where the lowest ion energy is observed. Even at the comparatively high pressure (600 mTorr) and low fundamental frequency of 5.5 MHz used here, tailoring the voltage waveforms is shown to efficiently create an asymmetry of both the ion energy and the ion flux in geometrically symmetric reactors

Absolute ozone densities in a radio-frequency driven atmospheric pressure plasma using two-beam UV-LED absorption spectroscopy and numerical simulations

International audienceThe efficient generation of reactive oxygen species (ROS) in cold atmospheric pressure plasma jets (APPJs) is an increasingly important topic, e.g. for the treatment of temperature sensitive biological samples in the field of plasma medicine. A 13.56 MHz radio-frequency (rf) driven APPJ device operated with helium feed gas and small admixtures of oxygen (up to 1%), generating a homogeneous glow-mode plasma at low gas temperatures, was investigated. Absolute densities of ozone, one of the most prominent ROS, were measured across the 11 mm wide discharge channel by means of broadband absorption spectroscopy using the Hartley band centred at lambda = 255 nm. A two-beam setup with a reference beam in Mach--Zehnder configuration is employed for improved signal-to-noise ratio allowing high-sensitivity measurements in the investigated single-pass weak-absorbance regime. The results are correlated to gas temperature measurements, deduced from the rotational temperature of the N2 (C 3 {{{\Pi }}}u \to B 3 {{{\Pi }}}g , upsilo = 0 \to 2) optical emission from introduced air impurities. The observed opposing trends of both quantities as a function of rf power input and oxygen admixture are analysed and explained in terms of a zero-dimensional plasma-chemical kinetics simulation. It is found that the gas temperature as well as the densities of O and O2(b{}1{{{Sigma }}}g ) influence the absolute O3 densities when the rf power is varied

Control of cambium initiation and activity in Arabidopsis by the transcriptional regulator AHL15

Plant secondary growth, which is the basis of wood formation, includes the production of secondary xylem, which is derived from meristematic cambium cells embedded in vascular tissue. Here, we identified an important role for the Arabidopsis thaliana (Arabidopsis) AT-HOOK MOTIF CONTAINING NUCLEAR LOCALIZED 15 (AHL15) transcriptional regulator in controlling vascular cambium activity. The limited secondary xylem development in inflorescence stems of herbaceous Arabidopsis plants was significantly reduced in ahl15 loss-of-function mutants, whereas constitutive or vascular meristem-specific AHL15 overexpression produced woody inflorescence stems. AHL15 was required for enhanced secondary xylem formation in the woody suppressor of overexpression of constans 1 (soc1) fruitfull (ful) double loss-of-function mutant. Moreover, we found that AHL15 induces vascular cambium activity downstream of the repressing SOC1 and FUL transcription factors, most likely similar to how it enhances lateral branching by promoting biosynthesis of the hormone cytokinin. Our results uncover a novel pathway driving cambium development, in which AHL15 expression levels act in parallel to and are dependent on the well-established TDIF-PXY-WOX pathway to differentiate between herbaceous and woody stem growth.Plant science

Vascular endothelial growth factor A (VEGF-A) mRNA expression levels decrease after menopause in normal breast tissue but not in breast cancer lesions

We hypothesized that the regulation of microvascular functions and angiogenesis in breast tissue, a well known target of ovarian steroid action, is dependent on the hormonal exposure of the breast. Relative expression levels of VEGF-A (vascular endothelial growth factor A), a putative key regulator of angiogenesis in breast cancer, were analysed in the tumour and the adjacent non-neoplastic breast tissue of 19 breast cancer patients by quantitative reverse transcriptase polymerase chain reaction. In non-neoplastic breast specimens the expression levels of all detected VEGF-A-isoforms (189, 165, 121) were significantly higher in premenopausal compared to post-menopausal women (P = 0.02) and were inversely correlated with the patient's age (P = 0.006). In contrast, in cancerous tissues menopausal status had no influence on VEGF-A-expression levels. Benign and malignant tissues exhibited a similar expression pattern of VEGF-A-isoforms relative to each other. Thus, the regulation of the vasculature in normal breast tissue, as opposed to breast cancer tissue, appears to be hormonally dependent. Endogenous and therapeutically used hormonal steroids might, therefore, cause clinically relevant changes of the angiogenic phenotype of the human breast. © 1999 Cancer Research Campaig