3,247 research outputs found
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Learning from AI : new trends in database technology
Recently some researchers in the areas of database data modelling and knowledge representations in artificial intelligence have recognized that they share many common goals. In this survey paper we show the relationship between database and artificial intelligence research. We show that there has been a tendency for data models to incorporate more modelling techniques developed for knowledge representations in artificial intelligence as the desire to incorporate more application oriented semantics, user friendliness, and flexibility has increased. Increasing the semantics of the representation is the key to capturing the "reality" of the database environment, increasing user friendliness, and facilitating the support of multiple, possibly conflicting, user views of the information contained in a database
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Asynchronous data retrieval from an object-oriented database
We present an object-oriented semantic database model which, similar to other object-oriented systems, combines the virtues of four concepts: the functional data model, a property inheritance hierarchy, abstract data types and message-driven computation. The main emphasis is on the last of these four concepts. We describe generic procedures that permit queries to be processed in a purely message-driven manner. A database is represented as a network of nodes and directed arcs, in which each node is a logical processing element, capable of communicating with other nodes by exchanging messages. This eliminates the need for shared memory and for centralized control during query processing. Hence, the model is suitable for implementation on a multiprocessor computer architecture, consisting of large numbers of loosely coupled processing elements
Trumping Tropes with Joke(r)s: The Daily Show âPlays the Race Cardâ
The race card is at once a trope and a topic that reductively prefigures racial meaning and performance. As a trope, it frames most racial discourse as a cheat or violation and thus prevents deliberation over material realities of race. As a topic, it exists as a resource for diminishing the social and political significance of persistent racial problems. We argue that The Daily Show with Jon Stewart (TDS) deploys political humor as a troping device that disrupts the contradictory logics of race card rhetoric and disorders a range of reductive commonplaces and figures of racial discourses. Specifically, we maintain that TDS pushes the boundaries of everyday negotiations of race, performs alternative conventions, and models manners of thinking, speaking, and acting useful for contemporary understandings of race. This essay therefore enhances the contemporary body of scholarship on politics and humor while expanding upon analyses of the rhetoricity of race and race relations
Towards photostatistics from photon-number discriminating detectors
We study the properties of a photodetector that has a number-resolving
capability. In the absence of dark counts, due to its finite quantum
efficiency, photodetection with such a detector can only eliminate the
possibility that the incident field corresponds to a number of photons less
than the detected photon number. We show that such a {\em non-photon}
number-discriminating detector, however, provides a useful tool in the
reconstruction of the photon number distribution of the incident field even in
the presence of dark counts.Comment: 7 pages, 4 figure
Non-Gaussian Scatter in Cluster Scaling Relations
We investigate the impact of non-Gaussian scatter in the cluster
mass-observable scaling relation on the mass and redshift distribution of
clusters detected by wide area surveys. We parameterize non-Gaussian scatter by
incorporating the third and forth moments (skewness and kurtosis) into the
distribution P(Mobs|M). We demonstrate that for low scatter mass proxies the
higher order moments do not significantly affect the observed cluster mass and
redshift distributions. However, for high scatter mass indicators it is
necessary for the survey limiting mass threshold to be less than 10^14 h^-1
Msol to prevent the skewness from having a significant impact on the observed
number counts, particularly at high redshift. We also show that an unknown
level of non-Gaussianity in the scatter is equivalent to an additional
uncertainty on the variance in P(Mobs|M) and thus may limit the constraints
that can be placed on the dark energy equation of state parameter w.
Furthermore, positive skewness flattens the mass function at the high mass end,
and so one must also account for skewness in P(Mobs|M) when using the shape of
the mass function to constrain cluster scaling-relations.Comment: 6 Pages, 3 Figures, to be submitted to ApJ Letter
Simultaneous aortic and renal artery reconstruction: Evolution of an eighteen-year experience
AbstractPurpose: We reviewed an 18-year experience with combined abdominal aortic and renal artery reconstruction (AOR) with a particular focus on patients' clinical risk profile and surgical results in contemporary practice as compared with earlier experience.Methods: One hundred seventy patients underwent AOR during the interval January 1, 1976 to June 30, 1994. To examine parameters representative of current practice, the cohort was divided into group I patients (n = 110) treated before 1990 and group II (n = 60) treated between 1990 and 1994. Median follow-up duration for the entire cohort was 8.4 ± 0.6 years. Renal artery reconstruction patency and patient survival rates were calculated by life-table methods. Logistic and Cox regression analysis were used to determine predictors of perioperative and long-term morbidity/mortality rates.Results: Although demographic features changed little over the review period, the detection (56% vs 73%, p = 0.03) and treatment with percutaneous transluminal coronary angioplasty/coronary artery bypass grafting (11% vs 40%, p = 0.0001) of associated coronary artery disease were more frequent in group II versus group I patients. Alternatively, renal insufficiency was more frequent in group I patients. The operative mortality rate for the entire cohort was 6.5% (group I = 9% vs group II = 2%, p = 0.06). Changing trends of surgical techniques over the review period included (group I vs II, respectively) increased use of bilateral simultaneous renal artery repair (12% vs 25%, p < 0.005) and transaortic endarterectomy as the renal artery reconstruction technique (3% vs 25%, p < 0.0001). Favorable response in blood pressure control was noted in 68% of group II patients. The cumulative 5-year survival rate for all patients was 75% with an initial serum creatinine of 2.0 mg/dl or greater being the only negative predictor of late survival after regression analysis.Conclusion: The current operative mortality rate for AOR is in the range anticipated for aortic surgery alone, and this appears to be related to improved detection and treatment of associated coronary artery disease and intervention before major deterioration in renal function. These findings coupled with currently available natural history data relative to renovascular disease justify an aggressive approach with AOR when significant renal artery stenosis is detected during evaluation of aortic disease. (J VASC SURG 1995;21:916-25.
A One Health Framework for the Evaluation of Rabies Control Programmes: A Case Study from Colombo City, Sri Lanka
<div><p>Background</p><p>One Health addresses complex challenges to promote the health of all species and the environment by integrating relevant sciences at systems level. Its application to zoonotic diseases is recommended, but few coherent frameworks exist that combine approaches from multiple disciplines. Rabies requires an interdisciplinary approach for effective and efficient management.</p><p>Methodology/Principal Findings</p><p>A framework is proposed to assess the value of rabies interventions holistically. The economic assessment compares additional monetary and non-monetary costs and benefits of an intervention taking into account epidemiological, animal welfare, societal impact and cost data. It is complemented by an ethical assessment. The framework is applied to Colombo City, Sri Lanka, where modified dog rabies intervention measures were implemented in 2007. The two options included for analysis were the control measures in place until 2006 (âbaseline scenarioâ) and the new comprehensive intervention measures (âinterventionâ) for a four-year duration. Differences in control cost; monetary human health costs after exposure; Disability-Adjusted Life Years (DALYs) lost due to human rabies deaths and the psychological burden following a bite; negative impact on animal welfare; epidemiological indicators; social acceptance of dogs; and ethical considerations were estimated using a mixed method approach including primary and secondary data. Over the four years analysed, the intervention cost US $1.03 million more than the baseline scenario in 2011 prices (adjusted for inflation) and caused a reduction in dog rabies cases; 738 DALYs averted; an increase in acceptability among non-dog owners; a perception of positive changes in society including a decrease in the number of roaming dogs; and a net reduction in the impact on animal welfare from intermediate-high to low-intermediate.</p><p>Conclusions</p><p>The findings illustrate the multiple outcomes relevant to stakeholders and allow greater understanding of the value of the implemented rabies control measures, thereby providing a solid foundation for informed decision-making and sustainable control.</p></div
Assessment of the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire for use in patients after neck dissection for head and neck cancer
BackgroundIn this crossâsectional study, the sensibility, testâretest reliability, and validity of the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire were assessed in patients who underwent neck dissection.MethodsSensibility was assessed with a questionnaire. Testâretest reliability was performed with completion of the DASH questionnaire 2 weeks after initial completion; validity, by evaluating differences in scores between patients undergoing different types of neck dissections and correlating DASH scores with Neck Dissection Impairment Index (NDII) scores.ResultsThe DASH questionnaire met sensibility criteria. For testâretest reliability analysis, the intraclass coefficient was 0.91. The DASH questionnaire showed differences between patients who underwent accessory nerveâsacrifice and nerveâsparing neck dissection. DASH questionnaire scores strongly correlated with NDII scores (râ=ââ0.86).ConclusionAlthough this study provides preliminary data on some psychometric properties of the DASH questionnaire in patients who have undergone a neck dissection, further assessment of responsiveness and other properties are required. © 2014 Wiley Periodicals, Inc. Head Neck 37: 234â242, 2015Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110617/1/hed23593.pd
Renal artery reconstruction for the preservation of renal function
AbstractPurpose: We reviewed a 13-year experience with an emphasis on long-term survival and renal function response when renal artery reconstruction (RAR) was performed primarily for the preservation or restoration of renal function in patients who had atherosclerotic renovascular disease.Methods: From January 1, 1980, to June 30, 1993, 139 patients underwent RAR for renal function salvage and were retrospectively reviewed. Inclusion criteria were either preoperative serum creatinine level >2.0 mg/dl (67% of patients) or RAR to the entire functioning renal mass irrespective of baseline renal function. Patient survival was calculated by life-table methods. Cox regression analysis was used to determine relative risk (RR) estimates for the late outcomes of continued deterioration of renal function and late survival after RAR. A logistic regression model was used to evaluate variables associated with perioperative complications.Results: Clinical characteristics of the cohort were notable for advanced cardiac (history of congestive heart failure, 27%; angina, 22%; previous myocardial infarction, 19%) and renal disease (serum creatinine level <2.0 mg/dl, 33%; 2.0 mg/dl to 3.0 mg/dl, 40%, >3.0 mg/dl, 27%). Cardiac disease was the principle cause of early (6 of 11 operative deaths) and late death. Operative management consisted of aortorenal bypass in 47%, extraanatomic bypass in 45%, and endarterectomy in 8%; 45% of patients required combined aortic and RAR. The operative mortality rate was 8%; significant perioperative renal dysfunction occurred in 10%. Major operative morbidity was associated with increasing azotemia (RR = 2.1; p = 0.001; 95% confidence interval [CI], 1.3 to 4.7 for each 1.0 mg/dl increase in baseline creatinine level). Of those patients who had a baseline creatinine level â„2.0 mg/dl, 54% had â„20% reduction in creatinine level after RAR. Late follow-up data were available for 87% of operative survivors at a mean duration of 4 years (range, 6 weeks to 12.6 years). Actuarial survival at 5 years was 52% ± 5%. Continued deterioration in renal function occurred in 24% of patients who survived operation, and eventual dialysis was required in 15%. Deterioration of renal function after RAR was associated with increasing levels of preoperative creatinine (RR = 1.6; 95% CI, 1.2 to 1.8; p = 0.001 for each 1.0 mg/dl increment in baseline creatinine level), and inversely related to early postoperative improvement in creatinine level (RR = 0.41; 95% CI, 0.2 to 0.9; p = 0.04).Conclusions: Intervention before major deterioration in renal function and an aggressive posture toward the frequently associated coronary artery disease are necessary to improve long-term results when RAR is performed for renal function salvage. (J Vasc Surg 1996;24:371-82.
Use of sonic tomography to detect and quantify wood decay in living trees.
Premise of the studyField methodology and image analysis protocols using acoustic tomography were developed and evaluated as a tool to estimate the amount of internal decay and damage of living trees, with special attention to tropical rainforest trees with irregular trunk shapes.Methods and resultsLiving trunks of a diversity of tree species in tropical rainforests in the Republic of Panama were scanned using an Argus Electronic PiCUS 3 Sonic Tomograph and evaluated for the amount and patterns of internal decay. A protocol using ImageJ analysis software was used to quantify the proportions of intact and compromised wood. The protocols provide replicable estimates of internal decay and cavities for trees of varying shapes, wood density, and bark thickness.ConclusionsSonic tomography, coupled with image analysis, provides an efficient, noninvasive approach to evaluate decay patterns and structural integrity of even irregularly shaped living trees
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