625 research outputs found

    Is environmental efficiency trade inducing or trade hindering?

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    Cataloged from PDF version of article.Global efforts to identify strategies for sustainable economic growth and development underline the need for understanding important links between environmental policies and international trade. In this paper, by constructing an environmental efficiency index for 111 countries from 1980 to 2009, we are able to empirically test for one such link. An improvement in the environmental efficiency index in terms of carbon dioxide emissions reflects a decrease in the cost of efforts to mitigate the environmental costs associated with growth. Countries that improve their environmental efficiency are found to experience strong international trade effects, both through increased exports and increased imports. While the positive link between efficiency improvements and exports is supportive of the Porter hypothesis, the positive link between efficiency improvements and imports is supportive of strong positive income effects on account of environmental efforts. These results, which are robust to alternative estimation strategies, lend strong support to global efforts to improve countries' environmental efficiencies. © 2014 Elsevier B.V

    FMR Study of Co/Ti Bilayer Thin Films

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    . We focused on the interaction between two ferromagnetic cobalt layers through a non-magnetic titanium layer. The magnetic properties of the structure were characterized by ferromagnetic resonance technique (FMR). The data were collected as a function of non-magnetic titanium layer thickness. Co/Ti multilayer (Ti (50 {\AA})/Co(45 {\AA})/Ti(2-40 {\AA})/Co(40 {\AA})/Ti(100 {\AA}))films were grown onto naturally oxidized p-type single crystal Si (100) substrate at UHV condition with magnetron sputtering system at room temperature. The thickness of Ti spacer layer ranges from 2 to 40 {\AA} with 2 {\AA} steps. We did not observe usual optic and acoustic modes; instead we had two broad overlapped peaks for the films ranged from 6 {\AA} to 40 {\AA}. One interesting result was the high anisotropic resonance field values for these films. Exchange coupling between ferromagnetic layers causes shift on resonance field values but these shifts in our samples were much larger than expected. This large anisotropic behavior is not clear at the moment. Our theoretical model was not able to determine a value for the exchange coupling parameter. One reason can be the close thickness values for Co sublayers. The other reason can be the Ti non-magnetic layer. If titanium did not grow layer by layer on cobalt, the cobalt ferromagnetic layers may behave as a single layer. As a result one cannot observe exchange interaction between ferromagnetic layers through non-magnetic spacer.Comment: 6 pages, 5 figure

    Topological surface transport in epitaxial SnTe thin films grown on Bi₂Te₃

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    The topological crystalline insulator SnTe has been grown epitaxially on a Bi₂Te₃ buffer layer by molecular beam epitaxy. In a 30-nm-thick SnTe film, p- and n-type carriers are found to coexist, and Shubnikov–de Haas oscillation data suggest that the n-type carriers are Dirac fermions residing on the SnTe (111) surface. This transport observation of the topological surface state in a p-type topological crystalline insulator became possible due to a downward band bending on the free SnTe surface, which appears to be of intrinsic origin

    Room-temperature ferromagnetism in Sr_(1-x)Y_xCoO_(3-delta) (0.2 < x < 0.25)

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    We have measured magnetic susceptibility and resistivity of Sr1−x_{1-x}Yx_xCoO3−δ_{3-\delta} (x=x= 0.1, 0.15, 0.2, 0.215, 0.225, 0.25, 0.3, and 0.4), and have found that Sr1−x_{1-x}Yx_xCoO3−δ_{3-\delta} is a room temperature ferromagnet with a Curie temperature of 335 K in a narrow compositional range of 0.2 ≤x≤\leq x\leq 0.25. This is the highest transition temperature among perovskite Co oxides. The saturation magnetization for x=x= 0.225 is 0.25 μB\mu_B/Co at 10 K, which implies that the observed ferromagnetism is a bulk effect. We attribute this ferromagnetism to a peculiar Sr/Y ordering.Comment: 5 pages, 4 figure

    Electrode Fixation with Bone Cement or Stimloc (R) in Deep Brain Stimulation Surgery: A Comparative Study

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    AIM: To examine the postoperative outcomes of electrode fixation using bone cement and Stimloc?? in patients with Parkinson???s MATERIAL and METHODS: Between 2016 and 2018, permanent electrode fixation was performed in 30 patients with PD, of which 15 received bone cement and the remaining 15 received Stimloc??. Data regarding preoperative Unified Parkinson???s Disease Rating Scale (UPDRS) III scores, levodopa equivalent daily dose (LEDD) values, surgery duration, and the fixation technique used were recorded. Brain computed tomography was performed for early postoperative evaluation of pneumocephalus and possible hematoma as well as for the determination of migration 1 year postoperatively. UPDRS III scores and LEDD values were re-evaluated 1 year postoperatively; surgery duration, clinical effectiveness, and complication rates were compared between the two fixation techniques. RESULTS: A statistically significant difference in application time was observed between the two techniques (bone cement: 21 min, Stimloc??: 6 min). After 1 year from surgery, 0.92- and 0.88-mm migrations were observed in the bone cement and Stimloc?? groups, respectively. A significant correlation between migration and the pneumocephalus volume was observed in both groups. No differences were observed between the groups regarding infection, migration, pneumocephalus volume, wound erosion, and CONCLUSION: Stimloc?? is preferred over bone cement for electrode fixation in DBS surgeries as it is associated with shorter application duration; this increases patient comfort and tolerance during awake surgery. Clinical efficacy and complication rates associated with both techniques are similar
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