330 research outputs found
Depositional system and palaeoclimatic interpretations of Middle to Late Pleistocene travertines: Kocabas, Denizli, south-west Turkey
Identification of multiple generation oil inclusions trapped in quartz single crystals using stepwise heating chemical ionisation mass spectroscopy
The Face of the Firm : The Impact of Employer Branding on Diversity
Drawing upon an employer branding lens to help explore and inform our understanding of the marketing of workforce diversity, here we argue that diversity is understood and used in an aesthetic and commercialized way, rather than with a focus upon the inclusion of disadvantaged groups. Our analysis of the marketing and diversity practices of four small and medium-sized law firms demonstrates a continued access-and-legitimacy approach to diversity: that a desire for successful employer branding still supersedes organizational commitment to equal opportunities and diversity management in practice. We argue that this commercialized approach leads to several contradictions, which in turn reproduce the market-based perspective of diversity, relegating employees primarily to the aesthetics of race and gender and the affiliated skills and resources. In theorizing the processes by which diversity is undermined and functions solely to enhance business image and increase organizational performance, we highlight how an employer branding lens enables us to identify and understand contradictions between diversity policy and practice in a different way, by linking aesthetics with the marketing of the brand
CAM LiF KATKISININ BETON DAYANIMINA ETKiSİ
Bu 9ahjmada, %0.2, 0.4 ve 0.6 aglfhk oranlannda earn liflerle katkllandmlmlj beton matrisli kompozit
malzemenin mekanik davranJ~lafl aramm
belirlenmesi, 09 nokta ve dart nokta egilme deneyleri ile geryekle~tirilmi~tjr. Cam litlerle katkllandlfllanbetonun
gekme ve egilme dayammlarmm arttlgl, basm9 mukavemetinin ise azaldlgl yapilan deneylerde tespit edilmijtir.
09 nokta egilme deneyleri ile elde edilen mukavemet sonu9larmm, d6rt nokta egilmeye g6re daha yUksek oldugu
g6zlenmijtir. Beton matrisi katkllandlfan earn litler, matris igerisinde homojen olarak yayilmlj bir donatl gibi
9ahjarak, U9boyutlu bir mikro takviye vazifesi g6rmUjlerdir. Basmy deneyi slrasmda bOjluk gibi davranan bu
lifler basll1ydayammmJ di.i$tirmU~lerdir
Depositional architecture, facies character and geochemical signature of the Tivoli travertines (pleistocene, acque albule basin, central Italy)
Facies character, diagenesis, geochemical signature, porosity, permeability, and geometry of the
upper Pleistocene Tivoli travertines were investigated integrating information from six borehole cores, drilled along
a 3 km N-S transect, and quarry faces, in order to propose a revised depositional model. Travertines overlie lacustrine
and alluvial plain marls, siltstones, sandstones and pyroclastic deposits from the Roman volcanic districts. In the
northern proximal area, with respect to the inferred hydrothermal vents, travertines accumulated in gently-dipping,
decametre-scale shallow pools of low-angle terraced slopes. The intermediate depositional zone, 2 km southward,
consisted of smooth and terraced slopes dipping S and E. In the southernmost distal zone, travertine marshes
dominated by coated vegetation and Charophytes interfingered with lacustrine siltstones and fluvial sandstones and
conglomerates. Travertine carbon and oxygen stable isotope data confirm the geothermal origin of the precipitating
spring water. The travertine succession is marked by numerous intraclastic/extraclastic wackestone to rudstone
beds indicative of non-deposition and erosion during subaerial exposure, due to temporary interruption of the
vent activity or deviation of the thermal water flow. These unconformities identify nine superimposed travertine
units characterized by aggradation in the proximal zone and southward progradation in the intermediate to distal
zones. The wedge geometry of the travertine system reflects the vertical and lateral superimposition of individual
fan-shaped units in response to changes in the vent location, shifting through time to lower elevations southward.
The complexity of the travertine architecture results from the intermittent activity of the vents, their locations, the
topographic gradient, thermal water flow paths and the rates and modes of carbonate precipitation
Acoustic properties in travertines and their relation to porosity and pore types
Sonic velocities of Pleistocene travertines were measured under variable confining pressures. Combined with petrographical characteristics and petrophysical data, i.e. porosity, permeability and density, it was determined that travertine porosity, pore types and cementation control compressional-wave (Vp) and shear-wave velocity (Vs). At 40 MPa confining pressures, Vp ranges between 3695 and 6097 m/s and Vs between 2037 and 3140 m/s. Velocity variations in travertines are, as with all carbonates, primarily linked to sample heterogeneity, i.e. differences in fabric, texture and porosity. They thus not necessarily emanate from changes in mineralogy or composition. Body wave velocities have a positive correlation with sample density and an inverse correlation with porosity. The travertines, sampled in extensional settings with normal faulting activity, define a specific compressional-wave velocity (y-axis) versus porosity (x-axis) equation, i.e. (log(y) = −0.0048x + 3.7844) that differs from the Vp-porosity paths defined by marine carbonates. Acoustic wave velocities are higher for travertines than for marine carbonates. Travertine precipitates form rigid rock frames, often called framestone, with large primary pores. Marine carbonates on the other hand often consist of (cemented) transported sediments, resulting in a rock frame that permits slower wave propagation when compared to the continental limestones.Acoustic velocity variations are linked to variations in pore types. Mouldic pores (macropores) show faster wave propagation than expected from their total porosities. Microporosity, interlaminar and interpeloidal porosity result in slower acoustic velocities. Framework pores and micro-moulds are associated with lowered acoustic velocities, while vug porosity is found above, on and below the general velocity-porosity trend. Not only the pore type, but also pore shapes exert control on body wave velocities. Cuboid-and rod-like pore shapes increase the velocity, while plate-and blade-like pore shapes have a negative effect on the velocity. The study demonstrates how seismic sections in travertine systems can contain seismic reflections that are not caused by non-carbonate intercalations, but relate to geobody boundaries, in which the seismic expression is function of porosity, pore types and shapes. This study provides and relates petrophysical data, i.e. porosity, permeability and acoustic velocities of travertines and is of importance for the interpretation of seismic reflection data in subsurface continental carbonate reservoirs
A Unified Clumped Isotope Thermometer Calibration (0.5–1100°C) Using Carbonate‐Based Standardization
Defining quantitative stream disturbance gradients and the additive role of habitat variation to explain macroinvertebrate taxa richness
Most studies dealing with the use of ecological indicators and other applied ecological research rely on some definition or concept of what constitutes least-, intermediate- and most-disturbed condition. Currently, most rigorous methodologies designed to define those conditions are suited to large spatial extents (nations, ecoregions) and many sites (hundreds to thousands). The objective of this study was to describe a methodology to quantitatively define a disturbance gradient for 40 sites in each of two small southeastern Brazil river basins. The assessment of anthropogenic disturbance experienced by each site was based solely on measurements strictly related to the intensity and extent of anthropogenic pressures. We calculated two indices: one concerned site-scale pressures and the other catchment-scale pressures. We combined those two indices into a single integrated disturbance index (IDI) because disturbances operating at both scales affect stream biota. The local- and catchment-scale disturbance indices were weakly correlated in the two basins (r = 0.21 and 0.35) and both significantly (p \u3c 0.05) reduced site EPT (insect orders Ephemeroptera, Plecoptera, Trichoptera) richness. The IDI also performed well in explaining EPT richness in the basin that presented the stronger disturbance gradient (R2 = 0.39, p \u3c 0.001). Natural habitat variability was assessed as a second source of variation in EPT richness. Stream size and microhabitats were the key habitat characteristics not related to disturbances that enhanced the explanation of EPT richness over that attributed to the IDI. In both basins the IDI plus habitat metrics together explained around 50% of EPT richness variation. In the basin with the weaker disturbance gradient, natural habitat explained more variation in EPT richness than did the IDI, a result that has implications for biomonitoring studies. We conclude that quantitatively defined disturbance gradients offer a reliable and comprehensive characterization of anthropogenic pressure that integrates data from different spatial scales
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