3,295 research outputs found
Balloon logging with the inverted skyline
There is a gap in aerial logging techniques that has to be filled. The need for a simple, safe, sizeable system has to be developed before aerial logging will become effective and accepted in the logging industry. This paper presents such a system designed on simple principles with realistic cost and ecological benefits
Where there is a wind, there is a way
A shift in USA energy policy from oil or natural gases to thermonuclear fission and solar energy is predicted. A massive diversified energy research and development effort to productively harness the energy in the winds is outlined to develop commercially feasible wind energy conversion systems - considered a form of solar energy - in the near future
An investigation of surface albedo variations during the recent sahel drought
Applications Technology Satellite 3 green sensor data were used to measure surface reflectance variations in the Sahara/Sahel during the recent drought period; 1967 to 1974. The magnitude of the seasonal reflectance change is shown to be as much as 80% for years of normal precipitation and less than 50% for drought years. Year to year comparisons during both wet and dry seasons reveal the existence of a surface reflectance cycle coincident with the drought intensity. The relationship between the green reflectance and solar albedo is examined and estimated to be about 0.6 times the reflectance change observed by the green channel
International Year of Planet Earth 7. Oceans: Submarine Landslides and Consequent Tsunamis in Canada
Canada has the longest coastline and largest continental margin of any nation in the World. As a result, it is more likely than other nations to experience marine geohazards such as submarine landslides and consequent tsunamis. Coastal landslides represent a specific threat because of their possible proximity to societal infrastructure and high tsunami potential; they occur without warning and with little time lag between failure and tsunami impact. Continental margin landslides are common in the geologic record but rare on human timescales. Some ancient submarine landslides are massive but more recent events indicate that even relatively small slides on continental margins can generate devastating tsunamis. Tsunami impact can occur hundreds of km away from the source event, and with less than 2 hours warning. Identification of high-potential submarine landslide regions, combined with an understanding of landslide and tsunami processes and sophisticated tsunami propagation models, are required to identify areas at high risk of impact.
SOMMAIRE
Le Canada possède les plus longues zones côtières et marges continentales du monde. Donc, il est significativement exposé aux géorisques marins, comme les glissements de terrain sousmarins (GTSM) comportent également des risques de tsunamis. Les glissements côtiers représentent un risque significatif vu la proximité d’infrastructures et leur capacité de produire des tsunamis. Ils se produisent sans aver-tissement et peu de délai existe entre leur déclenchement et l’impact possible d’un tsunami. Les GTSM en marge continentale sont communs dans l’histoire géologique mais rare à l’échelle de l’histoire humaine. Quelques anciens dépôts glissés sont de dimensions importantes, mais les nouvelles évidences suggèrent que même les petits glissements sur les marges continentales peuvent générer des tsunamis. L’impact des tsunamis peut être ressenti à des centaines de km de la source et l’impact est possible avec moins de 2 heures d’avertissement. L’identification des régions à potentiel élevé pour l’instabilité des pentes combinées à la compréhension des processus de formation de GTSM et de tsunami, et à des modèles sophistiqués de propagation, sont nécessaires pour identifier les secteurs hautement à risque d’impact
AN INVESTIGATIVE STUDY INTO THE RELATIONSHIP OF BONE MORPHOGENETIC PROTEIN ANTAGONIST EXPRESSION AND OSTEOCYTE DENSITY BY REGION AND QUADRANT
The role of cytokines and cell behavior and viability with respect to bone remodeling and bone behavior is an exciting area of orthopedic research. The purpose of this study was to investigate the relationships between BMP antagonist expression and osteocyte density, lacunar densities and osteocyte viability in cortical bone. Samples of unloaded tibial bone obtained from six C57Bl/6 mice were immunohistochemically stained for gremlin and noggin expression and also underwent methyl green staining to determine osteocyte presence. Bone sections were divided into four quadrants (cranial, caudal, medial and lateral) and three regions (proximal, mid shaft and distal), followed by analysis across these quadrants and regions. The results showed matching regional differences in gremlin expression with regional variations in osteocyte density, lacunar density, and osteocyte viability. These variations were supported by positive correlations found via regression analysis. Regression analysis also showed marginal negative correlations between noggin expression and osteocyte density and osteocyte viability, supported by regional ANOVA results. Further research on loaded bone samples is needed if the relationship between these BMP antagonists and osteocyte densities are to be fully explained with respect to the bone remodeling process
A theoretical approach to the determination of magnetic torques by near field measurement
Theoretical approach to determination of magnetic torques on orbiting spacecraft by near-field measuremen
Representative bureaucracy: does female police leadership affect gender-based violence arrests?
Representative bureaucracy theory postulates that passive representation leads to active representation of minority groups. This article investigates the passive representation of female police officers at leadership levels and the active representation of women vis-a-vis gender-based violence arrest rates in the UK. Much of the extant research on representative bureaucracy is located at street level, with evidence showing that discretionary power of minority bureaucrats can lead to active representation. This article is focused on leadership levels of a public bureaucracy. The empirical research is based upon a panel dataset of female police officers as an independent variable and gender-based violence arrest rates as a dependent variable. The analysis reveals that there is little evidence of active representation of women by female police leadership
Bacterial pathogens encode suppressors of RNA-mediated silencing
Bacterial suppressors of silencing that inhibit multiple steps of plant microRNA biogenesis and function have recently been identified
Laboratory and Well-Log Velocity and Density Measurements from the Ontong Java Plateau: New in-situ corrections to laboratory data for pelagic carbonates
During Ocean Drilling Program Leg 130, sonic velocity and bulk density/porosity well logs were measured in five separate holes drilled through the sequence of pelagic carbonate oozes, chalks, and limestones that comprise the thick, continuous sedimentary cover on the Ontong Java Plateau. An internally consistent and continuous suite of shipboard laboratory velocity and sediment physical properties measurements were made from the top of each hole down through the entire logged interval. Because of the high quality of the data, extensive overlap of 500 m or more between the log and laboratory measurements at each hole, and the homogeneous nature of the sediments, we have been able to compare laboratory and in-situ log measurements in detail and to evaluate factors that alter laboratory data from their in-situ values. For measurements of bulk density and porosity, differences between laboratory and in-situ log measurements are very small and remain constant over the entire range of depths studied. We have applied a simple hydraulic rebound correction to the laboratory data that compensates for pore fluid expansion after removal of a sediment sample from in-situ conditions. The small, correctable differences between the laboratory and log data imply that mechanical rebound is significantly less than previous estimates (maximum near 5%) of rebound in pelagic carbonates. Furthermore, porosity rebound cannot be used to correct laboratory sonic velocity measurements to in-situ values. Such a rebound correction implicitly requires that laboratory and in-situ data must occupy identical fields on velocity-porosity crossplots. This condition is not met for the Ontong Java Plateau results because laboratory and in-situ logging data occupy distinct trends with little overlap between the two types of measurement. Mechanical rebound in pelagic carbonates cannot be used to correct either laboratory porosity or velocity measurements to in-situ values. The complex porosity systematics of these carbonates resulting from varying abundances of hollow foraminifer grains precluded use of an empirical correction derived from the log porosity and velocity data. Laboratory sonic velocity measurements can be corrected to in-situ values at all of the Ontong Java Plateau sites using a depth-based function derived from downhole differences between log and laboratory velocities in Hole 807A. The applicability of the depth correction implies that the effect of overburden pressure reduction on sediment elastic moduli is the most significant factor affecting laboratory velocity measurements. The depth correction to laboratory velocity measurements appears to be generally applicable to pelagic carbonate oozes and chalks of the Ontong Java Plateau, regardless of depositional depth or sediment age
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