330 research outputs found

    Learning Best Response Strategies for Agents in Ad Exchanges

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    Ad exchanges are widely used in platforms for online display advertising. Autonomous agents operating in these exchanges must learn policies for interacting profitably with a diverse, continually changing, but unknown market. We consider this problem from the perspective of a publisher, strategically interacting with an advertiser through a posted price mechanism. The learning problem for this agent is made difficult by the fact that information is censored, i.e., the publisher knows if an impression is sold but no other quantitative information. We address this problem using the Harsanyi-Bellman Ad Hoc Coordination (HBA) algorithm, which conceptualises this interaction in terms of a Stochastic Bayesian Game and arrives at optimal actions by best responding with respect to probabilistic beliefs maintained over a candidate set of opponent behaviour profiles. We adapt and apply HBA to the censored information setting of ad exchanges. Also, addressing the case of stochastic opponents, we devise a strategy based on a Kaplan-Meier estimator for opponent modelling. We evaluate the proposed method using simulations wherein we show that HBA-KM achieves substantially better competitive ratio and lower variance of return than baselines, including a Q-learning agent and a UCB-based online learning agent, and comparable to the offline optimal algorithm

    The missionary role of mainstream Christianity: Towards a narrative paradigm for social integration of minorities in pluralistic post-apartheid South Africa

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    This article attempts to add to the existing approaches of practical theology and specifically to the missionary approaches of mainline churches towards immigrants. This is an attempt to enhance the mission amongst immigrants by critically engaging with the two approaches, namely: mainstream and margins and pillarization. Notwithstanding the important contributions that these two approaches make to tolerance, integration and cohesion of differences I seek to point out some serious limitations of the two approaches. These limitations include social coercion, co-option, relativism and loss of identity. Considering these limitations a third approach, the narrative approach, takes serious community, tradition and symbol for more effective mission amongst immigrants by mainline churches. Social cohesion, a more realistic reality and integrated communities are some of the consequences of this approach when doing missionary activities amongst immigrants.DHE

    Turning round the telescope. Centre-right parties and immigration and integration policy in Europe

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    This is an Author's Original Manuscript of 'Turning round the telescope. Centre-right parties and immigration and integration policy in Europe', whose final and definitive form, the Version of Record, has been published in the Journal of European Public Policy 15(3):315-330, 2008 [copyright Taylor & Francis], available online at: http://www.tandfonline.com/doi.org/10.1080/13501760701847341

    Serial optical coherence microscopy for label-free volumetric histopathology

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    The observation of histopathology using optical microscope is an essential procedure for examination of tissue biopsies or surgically excised specimens in biological and clinical laboratories. However, slide-based microscopic pathology is not suitable for visualizing the large-scale tissue and native 3D organ structure due to its sampling limitation and shallow imaging depth. Here, we demonstrate serial optical coherence microscopy (SOCM) technique that offers label-free, high-throughput, and large-volume imaging of ex vivo mouse organs. A 3D histopathology of whole mouse brain and kidney including blood vessel structure is reconstructed by deep tissue optical imaging in serial sectioning techniques. Our results demonstrate that SOCM has unique advantages as it can visualize both native 3D structures and quantitative regional volume without introduction of any contrast agents

    Mastectomy versus radiotherapy as treatment for stage I-II breast cancer: A prospective randomized trial at the National Cancer Institute

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    In 1979, the National Cancer Institute in Bethesda, Maryland initiated a randomized, prospective trial to compare surgery versus radiation therapy in the treatment of stages I and II breast cancer. Surgical treatment consists of total mastectomy with axillary lymph node dissection (modified radical mastectomy) and breast reconstruction; radiation treatment consists of gross tumor excision, axillary lymph node dissection, and comprehensive irradiation including a boost dose to the tumor bed. All patients with pathologically positive axillary nodes receive 11 cycles of adjuvant Adriamycin ® /Cytoxan ® chemotherapy. As of December 1984, there have been 175 patients entered in the study. Twenty-three patients have developed disease recurrence (12 mastectomy, 11 radiation), but it is too early to obtain definitive treatment-related results. En 1979 l'Institut National du Cancer de Bethesda a lancé une étude prospective randomisée permettant de comparer les résultats respectifs de la chirurgie et de la radiothérapie en ce qui concerne les stades I et II du cancer du sein. Le traitement chirurgical consiste en la mastectomie totale complétée par le curage ganglionnaire axillaire (mastectomie totale modifiée); le traitement dit radiothérapique consiste en l'exérèse large de la tumeur associée au curage ganglionnaire axillaire et à l'administration d'une dose élevée de rayons au niveau du lit tumoral. Toutes les opérées dont les ganglions sont envahis reçoivent en outre 11 cycles d'une combinaison d'Adriamycine et Cytoxan. De 1979 à Décembre 1984, 175 malades ont fait l'objet de cette étude. Vingt-trois ont accusé une récidive (12 après mastectomie et 11 après traitement dit radiothérapique) mais il est encore trop tôt pour tirer des conclusions définitives de ces résultats. El Instituto Nacional de Cáncer de Bethesda inició en 1979 un ensayo prospectivo y aleatorio orientado a comparar el tratamiento quirúrgico versus radioterapia en el manejo del cáncer mamario en estados I y II. El tratamiento quirúrgico consistió de mastectomía total con disección ganglionar axilar (mastectomía radical modificada) y reconstrucción mamaria; el manejo radioterapéutico consistió de resección del tumor, disección de los ganglios linfáticos axilares e irradiación comprensiva incluyendo una dosis de refuerzo al lecho tumoral. Todos los pacientes con ganglios axilares histológicamente positivos recibieron 11 ciclos de quimioterapia adyuvante con Adriamicina/Citoxán. Hasta diciembre de 1984, 175 pacientes habían entrado al estudio. Veintitrés pacientes han desarrollado recurrencia de la enfermedad (12 mastectomía, 11 irradiación), pero es todavía muy temprano para derivar resultados definitivos.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41319/1/268_2005_Article_BF01655179.pd

    Autism as a disorder of neural information processing: directions for research and targets for therapy

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    The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which theyfeed, is hampered bythe large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself

    Label-free, multi-scale imaging of ex-vivo mouse brain using spatial light interference microscopy

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    Brain connectivity spans over broad spatial scales, from nanometers to centimeters. In order to understand the brain at multi-scale, the neural network in wide-field has been visualized in detail by taking advantage of light microscopy. However, the process of staining or addition of fluorescent tags is commonly required, and the image contrast is insufficient for delineation of cytoarchitecture. To overcome this barrier, we use spatial light interference microscopy to investigate brain structure with high-resolution, sub-nanometer pathlength sensitivity without the use of exogenous contrast agents. Combining wide-field imaging and a mosaic algorithm developed in-house, we show the detailed architecture of cells and myelin, within coronal olfactory bulb and cortical sections, and from sagittal sections of the hippocampus and cerebellum. Our technique is well suited to identify laminar characteristics of fiber tract orientation within white matter, e.g. the corpus callosum. To further improve the macro-scale contrast of anatomical structures, and to better differentiate axons and dendrites from cell bodies, we mapped the tissue in terms of its scattering property. Based on our results, we anticipate that spatial light interference microscopy can potentially provide multiscale and multicontrast perspectives of gross and microscopic brain anatomy.ope

    Shared computational principles for language processing in humans and deep language models

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    Departing from traditional linguistic models, advances in deep learning have resulted in a new type of predictive (autoregressive) deep language models (DLMs). Using a self-supervised next-word prediction task, these models generate appropriate linguistic responses in a given context. In the current study, nine participants listened to a 30-min podcast while their brain responses were recorded using electrocorticography (ECoG). We provide empirical evidence that the human brain and autoregressive DLMs share three fundamental computational principles as they process the same natural narrative: (1) both are engaged in continuous next-word prediction before word onset; (2) both match their pre-onset predictions to the incoming word to calculate post-onset surprise; (3) both rely on contextual embeddings to represent words in natural contexts. Together, our findings suggest that autoregressive DLMs provide a new and biologically feasible computational framework for studying the neural basis of language

    The Potential Influence of Common Viral Infections Diagnosed during Hospitalization among Critically Ill Patients in the United States

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    Viruses are the most common source of infection among immunocompetent individuals, yet they are not considered a clinically meaningful risk factor among the critically ill. This work examines the association of viral infections diagnosed during the hospital stay or not documented as present on admission to the outcomes of ICU patients with no evidence of immunosuppression on admission. This is a population-based retrospective cohort study of University HealthSystem Consortium (UHC) academic centers in the U.S. from the years 2006 to 2009. The UHC is an alliance of over 90% of the non-profit academic medical centers in the U.S. A total of 209,695 critically ill patients were used in this analysis. Eight hospital complications were examined. Patients were grouped into four cohorts: absence of infection, bacterial infection only, viral infection only, and bacterial and viral infection during same hospital admission. Viral infections diagnosed during hospitalization significantly increased the risk of all complications. There was also a seasonal pattern for viral infections. Specific viruses associated with poor outcomes included influenza, RSV, CMV, and HSV. Patients who had both viral and bacterial infections during the same hospitalization had the greatest risk of mortality RR 6.58, 95% CI (5.47, 7.91); multi-organ failure RR 8.25, 95% CI (7.50, 9.07); and septic shock RR 271.2, 95% CI (188.0, 391.3). Viral infections may play a significant yet unrecognized role in the outcomes of ICU patients. They may serve as biological markers or play an active role in the development of certain adverse complications by interacting with coincident bacterial infection
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