12,955 research outputs found

    The Role of Local Policies on Resource Utilization: Timber Harvesting in St. Tammany Parish, Louisiana

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    Seemingly unrelated regression was used to investigate if the passage of forestry-related ordinances has had an effect upon timber harvesting activities in St. Tammany Parish, Louisiana. Results indicate that a significant negative relationship exists between a $10,000 road bond ordinance and the level of timber harvest in the Parish.Resource /Energy Economics and Policy,

    Ecological comparison of the risks of mother-to-child transmission and clinical manifestations of congenital toxoplasmosis according to prenatal treatment protocol

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    We compared the relative risks of mother-to-child transmission of Toxoplasma gondii and clinical manifestations due to congenital toxoplasmosis associated with intensive prenatal treatment in Lyon and Austria, short term treatment in 51% of Dutch women, and no treatment in Danish women. For each cohort, relative risks were standardized for gestation at seroconversion. In total, 856 mother–child pairs were studied: 549 in Lyon, 133 in Austria, 123 in Denmark and 51 in The Netherlands. The relative risk for mother-to-child transmission compared to Lyon was 1·24 (95% CI: 0·88, 1·59) in Austria; 0·59 (0·41, 0·81) in Denmark; and 0·65 (0·37, 1·01) in The Netherlands. Relative risks for clinical manifestations compared with Lyon (adjusted for follow-up to age 3 years) were: Austria 0·19 (0·04, 0·51); Denmark 0·60 (0·13, 1·08); and The Netherlands 1·46 (0·51, 2·72). There was no clear evidence that the risk of transmission or of clinical manifestations was lowest in centres with the most intensive prenatal treatment

    Modulation of tumour colony growth by irradiated accessory cells.

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    The ability of human tumour cells to form colonies in soft agar is enhanced by the presence of autologous phagocytic/adherent cells. We investigated the effect of irradiation on the ability of the adherent cells to support human tumour colony formation. Relatively low doses of irradiation significantly increased the growth enhancing ability of adherent cells in 17/19 cases. The possibility that the enhancement was mediated by inactivation of radiosensitive contaminating lymphocytes was explored. Depletion of T lymphocytes from unirradiated adherent cells by a monoclonal antibody and complement resulted in little overall change in tumour colony growth. However, elimination of only the suppressor subset (OKT8+) of T lymphocytes resulted in increased colony growth relative to control values obtained with unirradiated adherent cells. In contrast, depletion of T lymphocytes from irradiated adherent cells by a pan T monoclonal antibody and complement decreased colony formation. Thus, the ability of irradiated macrophages to enhance tumour colony growth appeared to be mediated by a T lymphocyte. The effect of irradiation on isolated populations of macrophages and T lymphocytes was also examined. The enhanced ability of irradiated adherent cells to support tumor colony growth appeared to have been due to treatment of T lymphocytes alone. The results indicate that both adherent macrophages and lymphocytes may influence the growth of clonogenic human tumour cells

    Increased expression of programmed death ligand 1 (PD-L1) in human pituitary tumors

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    PURPOSE: Subsets of pituitary tumors exhibit an aggressive clinical courses and recur despite surgery, radiation, and chemotherapy. Because modulation of the immune response through inhibition of T-cell checkpoints has led to durable clinical responses in multiple malignancies, we explored whether pituitary adenomas express immune-related biomarkers that could suggest suitability for immunotherapy. Specifically, programmed death ligand 1 (PD-L1) has emerged as a potential biomarker whose expression may portend more favorable responses to immune checkpoint blockade therapies. We thus investigated the expression of PD-L1 in pituitary adenomas. METHODS: PD-L1 RNA and protein expression were evaluated in 48 pituitary tumors, including functioning and non-functioning adenomas as well as atypical and recurrent tumors. Tumor infiltrating lymphocyte populations were also assessed by immunohistochemistry. RESULTS: Pituitary tumors express variable levels of PD-L1 transcript and protein. PD-L1 RNA and protein expression were significantly increased in functioning (growth hormone and prolactin-expressing) pituitary adenomas compared to non-functioning (null cell and silent gonadotroph) adenomas. Moreover, primary pituitary adenomas harbored higher levels of PD-L1 mRNA compared to recurrent tumors. Tumor infiltrating lymphocytes were observed in all pituitary tumors and were positively correlated with increased PD-L1 expression, particularly in the functional subtypes. CONCLUSIONS: Human pituitary adenomas harbor PD-L1 across subtypes, with significantly higher expression in functioning adenomas compared to non-functioning adenomas. This expression is accompanied by the presence of tumor infiltrating lymphocytes. These findings suggest the existence of an immune response to pituitary tumors and raise the possibility of considering checkpoint blockade immunotherapy in cases refractory to conventional management

    Vanishing Fe 3d orbital moments in single-crystalline magnetite

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    We show detailed magnetic absorption spectroscopy results of an in situ cleaved high quality single crystal of magnetite. In addition the experimental setup was carefully optimized to reduce drift, self absorption, and offset phenomena as far as possible. In strong contradiction to recently published data, our observed orbital moments are nearly vanishing and the spin moments are quite close to the integer values proposed by theory. This very important issue supports the half metallic full spin polarized picture of magnetite.Comment: 7 pages, 4 figure

    Noise in laser speckle correlation and imaging techniques

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    We study the noise of the intensity variance and of the intensity correlation and structure functions measured in light scattering from a random medium in the case when these quantities are obtained by averaging over a finite number N of pixels of a digital camera. We show that the noise scales as 1/N in all cases and that it is sensitive to correlations of signals corresponding to adjacent pixels as well as to the effective time averaging (due to the finite sampling time) and spatial averaging (due to the finite pixel size). Our results provide a guide to estimation of noise level in such applications as the multi-speckle dynamic light scattering, time-resolved correlation spectroscopy, speckle visibility spectroscopy, laser speckle imaging etc.Comment: submitted 14 May 201

    The invisible power of fairness. How machine learning shapes democracy

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    Many machine learning systems make extensive use of large amounts of data regarding human behaviors. Several researchers have found various discriminatory practices related to the use of human-related machine learning systems, for example in the field of criminal justice, credit scoring and advertising. Fair machine learning is therefore emerging as a new field of study to mitigate biases that are inadvertently incorporated into algorithms. Data scientists and computer engineers are making various efforts to provide definitions of fairness. In this paper, we provide an overview of the most widespread definitions of fairness in the field of machine learning, arguing that the ideas highlighting each formalization are closely related to different ideas of justice and to different interpretations of democracy embedded in our culture. This work intends to analyze the definitions of fairness that have been proposed to date to interpret the underlying criteria and to relate them to different ideas of democracy.Comment: 12 pages, 1 figure, preprint version, submitted to The 32nd Canadian Conference on Artificial Intelligence that will take place in Kingston, Ontario, May 28 to May 31, 201
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