904 resultados para Drill and minor tactics


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More than 50 discrete volcanic ash layers were recovered at the five drill sites of the Blake Nose depth transect (Leg 171B, western central Atlantic). The majority of these ash layers are intercalated with Eocene hemipelagic sediments with a pronounced frequency maximum in the upper Eocene. Several ash layers appear to be deposited from volcanic fallout with little or no indication of secondary remobilization. They provide excellent stratigraphic markers for a correlation of the Leg 171B drill sites. Other ash layers were probably redeposited from volcaniclastic-rich turbidity currents, but they still represent geologically instantaneous events that can be used in stratigraphic correlation between adjacent drill holes. Additional nonvolcanic marker beds, like the suspect late Eocene impact event layer, were included in our hole-to-hole correlations. Stratigraphic and downcore positions of marker beds were compiled and plotted against existing composite depth records that were constructed to guide high-resolution sampling. Comparison of our correlation with the spliced composite sections of each drill site reveals several minor and some major discrepancies. These may result from drilling distortion or missing sections, from the lack of unambiguous criteria for the synchronism of ash layers, or from the systematic exclusion of marker-bed data in the construction of the spliced record. Integration of both correlation approaches will help eliminate most of the observed discrepancies.

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Concentrations of minor and trace elements (Li, Rb, Sr, Ba, Fe, and Mn) in interstitial water (IW) were found in samples collected during Ocean Drilling Program (ODP) Leg 166 from Sites 1005, 1006, and 1007 on the western flank of the Great Bahama Bank (GBB). Concentrations of Li range from near-seawater values immediately below the sediment/water interface to a maximum of 250 µM deep in Site 1007. Concentrations determined during shore-based studies are substantially lower than the shipboard data presented in the Leg 166 Initial Reports volume (range of 28-439 µM) because of broad-band interferences from high dissolved Sr concentrations in the shipboard analyses. Rubidium concentrations of 1.3-1.7 µM were measured in IW from Site 1006 when salinity was less than 40 psu. A maximum of 2.5 µM is reached downhole at a salinity of 50 psu. Shipboard and shore-based concentrations of Sr2+ are in excellent agreement and vary from 0.15 mM near the sediment water interface to 6.8 mM at depth. The latter represent the highest dissolved Sr2+ concentrations observed to date in sediments cored during the Deep Sea Drilling Project (DSDP) or ODP. Concentrations of Ba2+ span three orders of magnitude (0.1-227µM). Concentrations of Fe (<0.1-14 µM) and Mn (0.1-2 µM) exhibit substantially greater fluctuations than other constituents. The concentrations of minor and trace metals in pore fluids from the GBB transect sites are mediated principally by changes in pore-water properties resulting from early diagenesis of carbonates associated with microbial degradation of organic matter, and by the abundance of detrital materials that serve as a source of these elements. Downcore variations in the abundance of detrital matter reflect differences in carbonate production during various sea-level stands and are more evident at the more proximal Site 1005 than at the more pelagic Site 1006. The more continuous delivery of detrital matter deep in Site 1007 and throughout all of Site 1006 is reflected in a greater propensity to provide trace elements to solution. Concentrations of dissolved Li+ derive principally from (1) release during dissolution of biogenic carbonates and subsequent exclusion during recrystallization and (2) release from partial dissolution of Li-bearing detrital phases, especially ion-exchange reactions with clay minerals. A third but potentially less important source of Li+ is a high-salinity brine hypothesized to exist in Jurassic age (unsampled) sediments underlying those sampled during Leg 166. The source of dissolved Sr2+ is almost exclusively biogenic carbonate, particularly aragonite. Concentrations of dissolved Sr2+ and Ba2+ are mediated by the solubility of their sulfates. Barite and detrital minerals appear to be the more important source of dissolved Ba2+. Concentrations of Fe and Mn2+ in anoxic pore fluids are mediated by the relative insolubility of pyrite and incorporation into diagenetic carbonates. The principal sources of these elements are easily reduced Fe-Mn-rich phases including Fe-rich clays found in lateritic soils and aoelian dust.

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During the Mid-Pleistocene Transition (MPT), the dominant glacial-interglacial cyclicity as inferred from the marine d18O records of benthic foraminifera (d18Obenthic) changed from 41 kyr to 100 kyr years in the absence of a comparable change in orbital forcing. Currently, only two Mg/Ca-derived, high-resolution bottom water temperature (BWT) records exist that can be used with d18Obenthic records to separate temperature and ice volume signals over the Pleistocene. However, these two BWT records suggest a different pattern of climate change occurred over the MPT-a record from North Atlantic DSDP Site 607 suggests BWT decreased with no long-term trend in ice volume over the MPT, while South Pacific ODP Site 1123 suggests that BWT has been relatively stable over the last 1.5 Myr but that there was an abrupt increase in ice volume at ~900 kyr. In this paper we attempt to reconcile these two views of climate change across the MPT. Specifically, we investigated the suggestion that the secular BWT trend obtained from Mg/Ca measurements on Cibicidoides wuellerstorfi and Oridorsalis umbonatus species from N. Atlantic Site 607 is biased by the possible influence of D[CO3]2- on Mg/Ca values in these species by generating a low-resolution BWT record using Uvigerina spp., a genus whose Mg/Ca values are not thought to be influenced by D[CO3]2-. We find a long-term BWT cooling of ~2-3°C occurred from 1500 to ~500 kyr in the N. Atlantic, consistent with the previously generated C. wuellerstorfi and O. umbonatus BWT record. We also find that changes in ocean circulation likely influenced d18Obenthic, BWT, and d18Oseawater records across the MPT. N. Atlantic BWT cooling starting at ~1.2 Ma, presumably driven by high-latitude cooling, may have been a necessary precursor to a threshold response in climate-ice sheet behavior at ~900 ka. At that point, a modest increase in ice volume and thermohaline reorganization may have caused enhanced sensitivity to the 100 kyr orbital cycle.

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Drillhole-determined sea-ice thickness was compared with values derived remotely using a portable small-offset loop-loop steady state electromagnetic (EM) induction device during expeditions to Fram Strait and the Siberian Arctic, under typical winter and summer conditions. Simple empirical transformation equations are derived to convert measured apparent conductivity into ice thickness. Despite the extreme seasonal differences in sea-ice properties as revealed by ice core analysis, the transformation equations vary little for winter and summer. Thus, the EM induction technique operated on the ice surface in the horizontal dipole mode yields accurate results within 5 to 10% of the drillhole determined thickness over level ice in both seasons. The robustness of the induction method with respect to seasonal extremes is attributed to the low salinity of brine or meltwater filling the extensive pore space in summer. Thus, the average bulk ice conductivity for summer multiyear sea ice derived according to Archie's law amounts to 23 mS/m compared to 3 mS/m for winter conditions. These mean conductivities cause only minor differences in the EM response, as is shown by means of 1-D modeling. However, under summer conditions the range of ice conductivities is wider. Along with the widespread occurrence of surface melt ponds and freshwater lenses underneath the ice, this causes greater scatter in the apparent conductivity/ice thickness relation. This can result in higher deviations between EM-derived and drillhole determined thicknesses in summer than in winter.

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Defining the difference between successful and mediocre leaders is a quest that has attracted many renowned scholars, drawing vast amounts of research effort. Yet while there are excellent theoretical explanations of what leaders should do: exhibit transformational behaviours, demonstrate authenticity, build productive relationships with followers and so on; there is still a scarcity of empirically-based research advising practicing leaders how to do these things. This study seeks to provide guidance about the fine-grained processes that effective leaders use on a daily basis to undertake the core process of all leadership activity; influencing followers. Using a grounded research approach, this study employs qualitative methods to capture the detail of effective leader behaviour and the micro-level influence processes that leaders use to create effective follower outcomes. Conducted in the health services industry with medical and allied health leaders, the study sought to answer the question: What influence methods might effective, contemporary leaders be using? The study builds on existing influence research, seeking to extend and update the typology of 11 influence tactics originally developed by Yukl and others, and which has been static since the late 1990s. Eight new influence tactics were identified, offering practicing leaders a powerful suite of potential strategies and representing a significant contribution to the field. Further research is recommended to confirm the identified influence constructs and test the generalisability of these findings to broader leader populations in health organisations and other knowledge-based organisations.

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Material for this paper comes from as report commissioned by the Department of Family Services, Aboriginal and Islander Affairs. The report is the result of a multi strategy research project designed to assess the impact of gaming machines on the fundraising capacity of charitable and community organisations in Queensland. The study was conducted during the 1993 calendar year. The first Queensland gaming machine was commissioned on the 11 February, 1992 at 11.30 am in Brisbane at the Kedron Wavell Services Club. Eighteen more clubs followed that week. Six months later there were gaming machines in 335 clubs, and 250 hotels and taverns, representing a state wide total of 7,974 machines in operation. The 10,000 gaming machine was commissioned on the 18 March, 1993 and the 1,000 operational gaming machine site was opened on 18th February, 1994.

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Human papillomaviruses (HPV) are responsible for the most common human sexually transmitted viral infections, and high-risk types are responsible for causing cervical and other cancers. The minor capsid protein L2 of HPV plays important roles in virus entry into cells, localisation of viral components to the nucleus, in DNA binding, capsid formation and stability. It also elicits antibodies that are more cross-reactive between HPV types than does the major capsid protein L1, making it an attractive potential target for new-generation, more broadly protective subunit vaccines against HPV infections. However, its low abundance in natural capsids-12-72 molecules per 360 copies of L1-limits its immunogenicity. This review will explore the biological roles of the protein, and prospects for its use in new vaccines. © 2009 Springer-Verlag.

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This paper explores what we are calling “Guerrilla Research Tactics” (GRT): research methods that exploit emerging mobile and cloud based digital technologies. We examine some case studies in the use of this technology to generate research data directly from the physical fabric and the people of the city. We argue that GRT is a new and novel way of engaging public participation in urban, place based research because it facilitates the co- creation of knowledge, with city inhabitants, ‘on the fly’. This paper discusses the potential of these new research techniques and what they have to offer researchers operating in the creative disciplines and beyond. This work builds on and extends Gauntlett’s “new creative methods” (2007) and contributes to the existing body of literature addressing creative and interactive approaches to data collection.

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Financial literacy may not be as effective as previously thought in protecting against fraud victimisation. It does not inoculate investors from persuasion or social engineering tactics used by offenders to secure investment in fraudulent schemes. In fact, recent research indicates that overconfidence in investment knowledge may make individuals more susceptible to fraud. Using boiler room fraud as a case study, this article introduces the PREY (Profiled, Relational, Exploitable and Yielding) model to capture the psychological tactics used by fraud perpetrators to influence the thoughts and decision-making processes of individuals. The PREY model operationalizes the tenets of social engineering and demonstrates how such tactics could be re-engineered to increase the effectiveness of fraud prevention within the financial literacy context.

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Safety of repair, maintenance, alteration, and addition (RMAA) works have long been neglected because RMAAworks are often minute and only last for a short period of time. With rising importance of the RMAA sector in many developed societies, safety of RMAA works has begun to draw attention. Many RMAA contracting companies are small- and medium-sized enterprises (SMEs) that do not have comprehensive safety management systems. Existing safety legislation and regulations for new construction sites are not fully applicable to RMAAworks. Instead of relying on explicit and well-established safety systems, tacit safety knowledge plays an extremely important role in RMAA projects. To improve safety of RMAAworks, safety knowledge should be better managed. However, safety knowledge is difficult to capture in RMAA works. This study aims to examine safety management practices of RMAA contracting companies to see how safety knowledge of RMAA projects is managed. Findings show that RMAA contracting companies undertaking large-scale RMAA projects have more initiatives of safety management. Safety management of small-scale RMAA works relies heavily on the motivation of site supervisors and self-regulation of workers. Better tacit knowledge management improves safety performance. To enhance safety capability of RMAA contracting companies, a knowledge sharing culture should be cultivated. The government should provide assistance to SMEs to implement proper safety management practices in small-sized projects. Potentials of applying computer software technology in RMAA projects to capture, store, and retrieve safety information should be explored. Employees should be motivated to share safety knowledge by giving proper recognition to those who are willing to share.