14 research outputs found

    U-Pb, Re-Os, and 40Ar/39Ar geochronology of the Nambija Au-skarn and Pangui porphyry Cu deposits, Ecuador: implications for the Jurassic metallogenic belt of the Northern Andes

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    New U-Pb, Re-Os, and 40Ar/39Ar dates are presented for magmatic and hydrothermal mineral phases in skarn- and porphyry-related ores from the Nambija and Pangui districts of the Subandean zone, southeastern Ecuador. Nambija has been one of the main gold-producing centers of Ecuador since the 1980s due to exceptionally high-grade ores (average 15g/t, but frequently up to 300g/t Au). Pangui is a recently discovered porphyry Cu-Mo district. The geology of the Subandean zone in southeastern Ecuador is dominated by the I-type, subduction-related, Jurassic Zamora batholith, which intrudes Triassic volcanosedimentary rocks. The Zamora batholith is in turn cut by porphyritic stocks, which are commonly associated with skarn formation and/or porphyry-style mineralization. High precision U-Pb and Re-Os ages for porphyritic stocks (U-Pb, zircon), associated prograde skarn (U-Pb, hydrothermal titanite), and retrograde stage skarn (Re-Os, molybdenite from veins postdating gold deposition) of the Nambija district are all indistinguishable from each other within error (145Ma) and indicate a Late Jurassic age for the gold mineralization. Previously, gold mineralization at Nambija was considered to be Early Tertiary based on K-Ar ages obtained on various hydrothermal minerals. The new Jurassic age for the Nambija district is slightly younger than the 40Ar/39Ar and Re-Os ages for magmatic-hydrothermal minerals from the Pangui district, which range between 157 and 152Ma. Mineralization at Nambija and Pangui is associated with porphyritic stocks that represent the last known episodes of a long-lived Jurassic arc magmatism (∼190 to 145Ma). A Jurassic age for mineralization at Nambija and Pangui suggests that the Northern Andean Jurassic metallogenic belt, which starts in Colombia at 3° N, extends down to 5° S in Ecuador. It also adds a new mineralization style (Au-skarn) to the metal endowment of this bel

    31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

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    Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

    Polymer Membranes to Quarter-Wave Match Gaussian Optics

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    Why are there so few women in information technology? Assessing the role of personality in career choices

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    Despite increases in female labor force participation, women remain substantially under represented in most scientific and technical fields. The small number of women in engineering, physics, chemistry, computer science and other similar fields has variously been attributed to discrimination, differences in ability or choice. This paper uses a unique data set containing information on vocational interests to examine the determinants of entry in to Information Technology occupations. We show that men and women differ systematically in their interests, and that these differences can account for an economically and statistically large fraction of the occupational gender gap.

    IT Workforce Composition and Characteristics

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    Women are under represented in the information technology (IT) workforce. In the United States, although women make up about 45% of the overall labor force they make up only about 35% of the IT workforce. (Information Technology Association of America, 2003, p. 11). Within IT, women’s representation declines as one moves up to higher-level occupations. While women are relatively more numerous among data entry keyers and computer operators, they are relatively less likely to be found in high-level occupations like systems analysts and computer programmers. The relatively low representation of women in IT fields parallels a broader pattern of gender differentials in other scientific and technical fields. In all science, technology, engineering, and mathematics fields combined, women held 25.9% of jobs in 2003. Women’s representation varies widely by sub-fields, however; 65.8% of psychologists and 54.6% of social scientists are women, but only 10.4% of engineers, and 37.4% of natural scientists (Commission on Professionals in Science and Technology, 2004, p. 2). Over the course of the past 100 years, there has been a dramatic change in women’s economic role. In 1900, only one in five adult women worked outside the home, and most of these were young and unmarried (Goldin, 1990). Since then, male and female labor force participation rates have tended to converge. Between 1900 and 1950 there was a gradual expansion of women’s labor force participation. After World War II the pace of change accelerated sharply as more married women entered the labor force. During the 1960s and early 1970s a series of legal changes significantly broadened protection of women’s rights ending essentially all forms of overt discrimination (Fuchs, 1988; Long, 2001, p. 9-10). The removal of these barriers in combination with the availability of cheap and reliable birth control technology greatly facilitated the entry of women into higher education, and technical and professional positions (Goldin &amp; Katz, 2002). Nevertheless, as the figures cited at the outset reveal, women’s participation in IT and other technical fields has not increased as rapidly as it has in less technical fields. And in striking contrast to the general trend toward increasing female participation in most areas of the workforce, women’s share of the IT workforce in the United States has actually declined over the past two decades. Any effort to explain gender differences in IT must begin with an understanding of how the number, characteristics, and pay of women in IT have evolved over time, and across different sub-fields within IT. This chapter provides a foundation for this analysis by documenting recent changes in the number of women employed in IT, their demographic characteristics, and relative pay. </jats:p

    Economic and business dimensionsIncreasing gender diversity in the IT work force

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    Want to increase participation of women in IT work? Change the work.</jats:p

    A Case Study of Medical Device Wireless Coexistence Evaluation

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    Measurement of shielding effectiveness of electrically-small enclosures

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    In the following we propose a technique for determining the shielding effectiveness of an electrically small enclosure with an electrically small aperture. In particular, we use this technique to explore the shielding characteristics of rectangular boxes used to shield devices. Measurement and simulation results are presented in order to validate the technique and to show that, when a source is placed inside the box, different aperture shapes on the face of the enclosure will produce different internal and external field patterns, and have different shielding characteristics

    U–Pb, Re–Os, and 40Ar/39Ar geochronology of the Nambija Au-skarn and Pangui porphyry Cu deposits, Ecuador: implications for the Jurassic metallogenic belt of the Northern Andes

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    New U–Pb, Re–Os, and 40Ar/39Ar dates are presented for magmatic and hydrothermal mineral phases in skarn- and porphyry-related ores from the Nambija and Pangui districts of the Subandean zone, southeastern Ecuador. Nambija has been one of the main gold-producing centers of Ecuador since the 1980s due to exceptionally high-grade ores (average 15 g/t, but frequently up to 300 g/t Au). Pangui is a recently discovered porphyry Cu–Mo district. The geology of the Subandean zone in southeastern Ecuador is dominated by the I-type, subduction-related, Jurassic Zamora batholith, which intrudes Triassic volcanosedimentary rocks. The Zamora batholith is in turn cut by porphyritic stocks, which are commonly associated with skarn formation and/or porphyry-style mineralization. High precision U–Pb and Re–Os ages for porphyritic stocks (U– Pb, zircon), associated prograde skarn (U–Pb, hydrothermal titanite), and retrograde stage skarn (Re–Os, molybdenite from veins postdating gold deposition) of the Nambija district are all indistinguishable from each other within error (145 Ma) and indicate a Late Jurassic age for the gold mineralization. Previously, gold mineralization at Nambija was considered to be Early Tertiary based on K–Ar ages obtained on various hydrothermal minerals. The new Jurassic age for the Nambija district is slightly younger than the 40Ar/39Ar and Re–Os ages for magmatic–hydrothermal minerals from the Pangui district, which range between 157 and 152 Ma. Mineralization at Nambija and Pangui is associated with porphyritic stocks that represent the last known episodes of a long-lived Jurassic arc magmatism (∼190 to 145 Ma). A Jurassic age for mineralization at Nambija and Pangui suggests that the Northern Andean Jurassic metallogenic belt, which starts in Colombia at 3° N, extends down to 5° S in Ecuador. It also adds a new mineralization style (Au-skarn) to the metal endowment of this belt
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