2,421 research outputs found
The geology and mineralogy of copper lead, Zinc sulphide veins from Bulancak, Turkey
The Bulancak Cu-Pb-Zn sulphide veins are the best representatives of their type among the varied deposits of the Eastern Pontus Ore Province. Kuroko, vein, stockvjork, prophyry-type copper, skarn-type iron and manganese deposits with subduction related volcanicity have been described from this province by various authors. Petrographic study of the Country rocks, despite their hydrothermal alteration, shows that they are mainly calc-alkaline. Volcanicity took place from Upper (possibly Lower) Cretaceous to Miocene as indicated by intrusives dated at 25 million years. Ore microscopy studies have proved the first occurrence (in Turkey) of Betekhtinite (Cu, Fe)(_21)Pb(_2)S(_15) and Aikinite (PbCuBiS(_3))-Bismithinitre(Bi(_2)S(_3) solid solution minerals. Idaite is reported for the first time from the study area. Field and Laboratory work have shown the structural control of Mn, Fe and Cd distribution in sphalerites. Mn follows a NW-SE trending zone from Kusdere to Kasyatak whereas Fc-Cd distribution follows a SW-NE trending zone between Kovalik Sr. and Kuloglu along Kűçűkgűre Dere (stream), reflecting the dependance on the two major fracture systems in the area. Data based on a study of more than 2500 primary and secondary fluid inclusions in transparent ore and ganque minerals is given, including measurements on the temperature, pressure, density and salinity. The inclusions were moderately saline, salinity varying within the range 13.2 equivalent wf.% NaCl to almost fresh water indicated by a 3 density change from 0.74gm/cm(^3) in the early vein stage to 0.98 at the end of the base metal sulphide stage. These variations way reflect the mixture of deeply circulating meteoric waters with rising, saline, hydrothermal fluids. Homogenization temperatures ranged from ca. 340 C to 80 C. Inclusions in neighbouring early formed quart2 and sphalerite minerals from the same vein show a temperature rise from ca. 230 to 330 C in the early vein stage, and eventually boiling conditions were reached. At a later stage the fluids cooled from 330 C to ca. 80 C. in the base metal stage. The highest temperatures were obtained from the Tekmezar Group Veins, in comparison to the DarikBy Group Veins, indicating a horizontal temperature zoning in which the Bi-content of the aikinitebismuthinite solid solution minerals increases from West (Saridiken Dere) to east (Kornali Dere). Data obtained from isotherms indicates that the ore-bearing fluids rose along NW-SE trending faults. This explains the concentration of veins around the Selmanoglu, Gonurca Dere, and Uzllinltik Dere Faults. Simple cooling of the solutions, pressure fluctuations, density and replacement processes played major roles in the formation of these veins. Fluid inclusion studies combined with geological data, are considered to be useful parameters in mineral exploration to pinpoint the richest part of an orebody. Metal transport and the thermal history of vein mineralisation are discussed in the light of fluid inclusion data
A Critical Review for the Possibility of Science without ‘Eppue Si Muove’: From Thomas Kuhn’s Theory of Science to Psychology of Science
The theory of science that Thomas Kuhn built in the Structure of Scientific Revolutions was considered as a hypothetical framework in this study. Since the publication of the work, many questions have arisen that call for a psychology of science. These questions are moved to another dimension through the knowledge of the decision made within Galileo Affair, which occupies an important place in modern science, fundamentally arising from an epistemic struggle and emerging out of an unscientific base rather than the charge of unholiness. Abandoning the perspective which evaluates these questions within a historical process as a weak side of the Kuhnian theory of science, this study challenges the current approaches with an alternative approach. The epistemic complexity in the Kuhnian theory of science is an imperative complexity caused by human factors. From this perspective, there are potential questions for psychology of science as a field of study based on Kuhnian epistemology and it can be assumed that new problems may appear when the other epistemological questions which assumed as “answered” are reviewed in the scope of this study. The main thesis of this study is that psychology of science is possible as a valid and operationalizable research program based on Kuhnian theory of science
Caffeine-Induced Global Reductions in Resting-State BOLD Connectivity Reflect Widespread Decreases in MEG Connectivity.
In resting-state functional magnetic resonance imaging (fMRI), the temporal correlation between spontaneous fluctuations of the blood oxygenation level dependent (BOLD) signal from different brain regions is used to assess functional connectivity. However, because the BOLD signal is an indirect measure of neuronal activity, its complex hemodynamic nature can complicate the interpretation of differences in connectivity that are observed across conditions or subjects. For example, prior studies have shown that caffeine leads to widespread reductions in BOLD connectivity but were not able to determine if neural or vascular factors were primarily responsible for the observed decrease. In this study, we used source-localized magnetoencephalography (MEG) in conjunction with fMRI to further examine the origins of the caffeine-induced changes in BOLD connectivity. We observed widespread and significant (p < 0.01) reductions in both MEG and fMRI connectivity measures, suggesting that decreases in the connectivity of resting-state neuro-electric power fluctuations were primarily responsible for the observed BOLD connectivity changes. The MEG connectivity decreases were most pronounced in the beta band. By demonstrating the similarity in MEG and fMRI based connectivity changes, these results provide evidence for the neural basis of resting-state fMRI networks and further support the potential of MEG as a tool to characterize resting-state connectivity
Improved feeding and forages at a crossroads: Farming systems approaches for sustainable livestock development in East Africa
Dairy development provides substantial potential economic opportunities for smallholder farmers in East Africa, but productivity is constrained by the scarcity of quantity and quality feed. Ruminant livestock production is also associated with negative environmental impacts, including greenhouse gas (GHG) emissions, air pollution, high water consumption, land-use change, and loss of biodiversity. Improved livestock feeding and forages have been highlighted as key entry point to sustainable intensification, increasing food security, and decreasing environmental trade-offs including GHG emission intensities. In this perspective article, we argue that farming systems approaches are essential to understand the multiple roles and impacts of forages in smallholder livelihoods. First, we outline the unique position of forages in crop-livestock systems and systemic obstacles to adoption that call for multidisciplinary thinking. Second, we discuss the importance of matching forage technologies with agroecological and socioeconomic contexts and niches, and systems agronomy that is required. Third, we demonstrate the usefulness of farming systems modeling to estimate multidimensional impacts of forages and for reducing agro-environmental trade-offs. We conclude that improved forages in East Africa are at a crossroads: if adopted by farmers at scale, they can be a cornerstone of pathways toward sustainable livestock systems in East Africa.</p
Continuous Processing and Efficient Reaction Monitoring of a Hypervalent Iodine(III) Mediated Cyclopropanation Using Benchtop NMR Spectroscopy
Real-time NMR spectroscopy has proven to be a rapid and an effective monitoring tool to study the hypervalent iodine(III) mediated cyclopropanation. With the ever increasing number of new synthetic methods for carbon−carbon bond formation, the NMR monitoring of reactions is becoming a highly desirable enabling method. In this study, we have demonstrated the versatility of benchtop NMR using inline and online real-time monitoring methods to access mutually complementary information for process understanding, and we developed new approaches for real-time monitoring addressing challenges associated with better integration into continuous processes.University of Cambridge (Daphne Jackson Fellowship), iCON through CMAC (Grant ID: RG74817), Engineering and Physical Sciences Research Council (Critical Mass grant (Grant ID: EP/K009494K/1), Core Capability grant (Grant ID: EP/K039520/1
Livestock development and climate change in Turkana District, Kenya
The main purpose of the study presented here is to shed some light using simple and aggregated methods on the following question: In view of the expected climate change, is there also a long-term perspective for livestock development in the area, i.e. will the Turkana ecosystem be able to sustain livestock production during the next few decades? In our search for an answer to this question, we looked at the current pressure on the environment, tried to interpolate the predicted climate change to the Turkana District scale and started exploring some of the possible impacts of climate change on the environment and the people depending on it. Due to the simplistic nature of the analyses performed, we consider these figures to be indicative only. This study goes hand in hand with another one focussing on market access and opportunities
Healthcare Barriers of Residents at a Subsidized Housing Community
Introduction: Despite expanded healthcare programs, the low income and elderly lack coverage of vision, hearing, and dental services. Community services are often asked to fill these gaps. To evaluate the situation in Burlington, VT, we surveyed staff and residents in Burlington Housing Authority (BHA) subsidized housing to (1) identify gaps in healthcare coverage and (2) assess barriers to accessing those services in this population.https://scholarworks.uvm.edu/comphp_gallery/1207/thumbnail.jp
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