Improved Analysis of Highest-Degree Branching for Feedback Vertex Set

Recent empirical evaluations of exact algorithms for Feedback Vertex Set have demonstrated the efficiency of a highest-degree branching algorithm with a degree-based pruning heuristic. In this paper, we prove that this empirically fast algorithm runs in O(3.460^k n) time, where k is the solution size. This improves the previous best O(3.619^k n)-time deterministic algorithm obtained by Kociumaka and Pilipczuk (Inf. Process. Lett., 2014)

Refining Coarse-grained Spatial Data using Auxiliary Spatial Data Sets with Various Granularities

We propose a probabilistic model for refining coarse-grained spatial data by utilizing auxiliary spatial data sets. Existing methods require that the spatial granularities of the auxiliary data sets are the same as the desired granularity of target data. The proposed model can effectively make use of auxiliary data sets with various granularities by hierarchically incorporating Gaussian processes. With the proposed model, a distribution for each auxiliary data set on the continuous space is modeled using a Gaussian process, where the representation of uncertainty considers the levels of granularity. The fine-grained target data are modeled by another Gaussian process that considers both the spatial correlation and the auxiliary data sets with their uncertainty. We integrate the Gaussian process with a spatial aggregation process that transforms the fine-grained target data into the coarse-grained target data, by which we can infer the fine-grained target Gaussian process from the coarse-grained data. Our model is designed such that the inference of model parameters based on the exact marginal likelihood is possible, in which the variables of fine-grained target and auxiliary data are analytically integrated out. Our experiments on real-world spatial data sets demonstrate the effectiveness of the proposed model.Comment: Appears in Proceedings of the Thirty-Third AAAI Conference on Artificial Intelligence (AAAI 2019

Surgical intervention for anomalous origin of the left coronary artery from the pulmonary artery: The Tokyo experience

AbstractBackground: Few studies after surgical repair of the anomalous origin of the left coronary artery have reported the importance of the mitral annuloplasty or the long-term results. Methods: Between January 1982 and March 2000, 29 patients with anomalous origin underwent surgical intervention at our institution (direct aortic reimplantation in 19 and Takeuchi procedure in 10). Age at the time of operation ranged from 2 months to 24 years (median, 29.3 months), and 9 patients were infants. Twenty-four patients had varying degrees of mitral incompetence. Simultaneous mitral annuloplasty at the anterolateral commissure was performed in all 24 patients with incompetence. Results: There were 2 hospital deaths among the infants, and no late deaths. Mean follow-up was 100 ± 57 months, and the actuarial survival was 93.1% at 10 years (70% confidence limits, 87-99). Cardiothoracic ratio at discharge was not decreasing significantly (P =.35); however, this value 5 years after the operation showed the significant decrease (P =.003) versus preoperative value. Preoperative mitral incompetence decreased in all but one of the operative survivors with mitral annuloplasty at the last follow-up. The left ventricular fractional shortening z-score was not normalized at discharge but was normalized in the late period. Conclusion: These data demonstrate that impaired left ventricular function normalized in the long term (even if it was below normal immediately after operation) after 2-coronary repair. We recommend that the simultaneous mitral annuloplasty should be performed at the time of operation for patients who have mitral incompetence with anomalous origin of the left coronary artery. (J Thorac Cardiovasc Surg 2001;121:792-7

Ibuprofen for neuroprotection after cerebral ischemia

ObjectiveIbuprofen has been shown to reduce cerebral ischemic injury, such as may occur after deep hypothermic circulatory arrest. We investigated whether ibuprofen has direct protective effects against excitotoxic neuronal injury, as may be seen after cerebral ischemia, by using a cell culture model.MethodsMixed cortical cultures containing neuronal and glial cells were prepared from fetal mice at 13 to 15 days gestation, plated on a layer of confluent astrocytes from 1- to 3-day-old postnatal pups. Near-pure neuronal cultures containing less than 5% astrocytes were obtained from mice of the same gestational stage. Slowly triggered excitotoxic injury was induced at 37°C by 24-hour exposure to 12.5 μmol/L N-methyl-D-aspartate or 50 μmol/L kainate. Neuronal death was quantified by release of lactate dehydrogenase from damaged cells. Data were analyzed using 1-way analysis of variance with Tukey post hoc multiple comparisons.ResultsIn mixed cultures, ibuprofen concentrations of 25 μg/mL, 50 μg/mL, and 100 μg/mL all significantly reduced N-methyl-D-aspartate–induced neuronal cell death from 74.5% to 56.1%, 38.7%, and 12.3%, respectively, revealing a strong dose response (P < .001). In near-pure cultures, ibuprofen at a concentration of 25 μg/mL failed to protect neurons, indicating that the neuroprotective effects of ibuprofen require interaction with glial cells. Furthermore, ibuprofen at 100 μg/mL was not protective against neuronal cell death induced by kainate exitotoxicity in near-pure culture but was effective in mixed cultures.ConclusionIbuprofen provides neuroprotection through glial cells against excitotoxic neuronal injury caused by glutamatergic excitotoxicity after cerebral ischemia as demonstrated by reduced neuronal cell death in mixed cell cultures. Further studies are needed to evaluate the potential of ibuprofen to reduce neurologic injury in patients experiencing an hypoxic/ischemic insult

Evaluating temperature effects on leaching behavior of geogenic arsenic and boron from crushed excavated rocks using shaking and nonshaking batch tests

The leaching behavior of arsenic and boron is evaluated in this work through two types of excavated rocks with geogenic contaminants under different temperatures. Excavated rocks with geogenic contaminants are expected to be used in embankments with appropriate countermeasures being taken against the risks brought about by geogenic contamination. The leaching behavior might change because of changes in the ground temperature. However, the effects of temperature on the leaching behavior of such rocks have not been well examined. Herein, batch leaching tests at temperatures between 5 and 60 °C were performed under shaking and nonshaking conditions. Mudstone and shale rock were crushed into particles smaller than 2 mm, which were required for the tests. The tests were carried out for durations ranging from 6 h to 15 days because changes in leaching kinetics also require careful evaluation. After conducting the nonshaking tests for 15 days at 40 °C, the mudstone sample leached arsenic and boron at concentrations of approximately 0.7 and 1.0 mg/L, respectively. The arsenic and boron concentrations were about 20 and 40% higher than those of the sample leached at a temperature of 20 °C. Elevated temperatures were seen to increase the leaching kinetics of the toxic elements. For the shale rock sample, the leaching rate for arsenic was 7.7 × 10⁻²/h at 40 °C, which was about 2.5 times greater than the value at 30 °C. The nonshaking tests showed higher leaching amounts of arsenic and boron than the shaking tests, especially at elevated temperatures. As unrealistic estimations should be avoided, nonshaking tests are suggested. Moreover, nonshaking tests lasting longer than 6 h are necessary due to the relatively slow dissolution of minerals

Time-delayed collective flow diffusion models for inferring latent people flow from aggregated data at limited locations

The rapid adoption of wireless sensor devices has made it easier to record location information of people in a variety of spaces (e.g., exhibition halls). Location information is often aggregated due to privacy and/or cost concerns. The aggregated data we use as input consist of the numbers of incoming and outgoing people at each location and at each time step. Since the aggregated data lack tracking information of individuals, determining the flow of people between locations is not straightforward. In this article, we address the problem of inferring latent people flows, that is, transition populations between locations, from just aggregated population data gathered from observed locations. Existing models assume that everyone is always in one of the observed locations at every time step; this, however, is an unrealistic assumption, because we do not always have a large enough number of sensor devices to cover the large-scale spaces targeted. To overcome this drawback, we propose a probabilistic model with flow conservation constraints that incorporate travel duration distributions between observed locations. To handle noisy settings, we adopt noisy observation models for the numbers of incoming and outgoing people, where the noise is regarded as a factor that may disturb flow conservation, e.g., people may appear in or disappear from the predefined space of interest. We develop an approximate expectation-maximization (EM) algorithm that simultaneously estimates transition populations and model parameters. Our experiments demonstrate the effectiveness of the proposed model on real-world datasets of pedestrian data in exhibition halls, bike trip data and taxi trip data in New York City

Safety and Efficacy of the Surgical Management of Hemodialysis Patients with Gastric Cancer

This retrospective study evaluated the short- and long-term outcomes after surgical management for gastric cancer in hemodialysis patients compared to non-dialysis patients. Twelve hemodialysis patients were compared with a propensity score-matched cohort of 39 gastric cancer patients who had not undergone hemodialysis. Short- and long-term outcomes along with scores estimating physiological ability and surgical stress were evaluated in both groups. The incidence of postoperative morbidity according to the Clavien-Dindo classification was higher in the hemodialysis gastric cancer group than in the non-dialysis gastric cancer group. The 5-year overall survival rate in the non-dialysis group was 69.2% after surgical resection for gastric cancer and 22.2% in the hemodialysis group. Patients with preoperative risk scores≥0.48 had significantly poorer survival outcomes compared to those with preoperative risk scores<0.48 (5-year survival rate, 83.3% vs. 39.4%, respectively). Our analyses suggest that hemodialysis patients undergoing surgery for gastric cancer have a significantly poorer postoperative prognosis and an elevated risk of postoperative complications

Multicascade-linked synthetic wavelength digital holography using an optical-comb-referenced frequency synthesizer

Digital holography (DH) is a promising method for non-contact surface topography because the reconstructed phase image can visualize the nanometer unevenness in a sample. However, the axial range of this method is limited to the range of the optical wavelength due to the phase wrapping ambiguity. Although the use of two different wavelengths of light and the resulting synthetic wavelength, i.e., synthetic wavelength DH, can expand the axial range up to a few tens of microns, this method is still insufficient for practical applications. In this article, a tunable external cavity laser diode phase-locked to an optical frequency comb, namely, an optical-comb-referenced frequency synthesizer, is effectively used for multiple synthetic wavelengths within the range of 32 um to 1.20 m. A multiple cascade link of the phase images among an optical wavelength (= 1.520 um) and 5 different synthetic wavelengths (= 32.39 um, 99.98 um, 400.0 um, 1003 um, and 4021 um) enables the shape measurement of a reflective millimeter-sized stepped surface with the axial resolution of 34 nm. The axial dynamic range, defined as the ratio of the maximum axial range (= 0.60 m) to the axial resolution (= 34 nm), achieves 1.7*10^8, which is much larger than that of previous synthetic wavelength DH. Such a wide axial dynamic range capability will further expand the application field of DH for large objects with meter dimensions.Comment: 19 pages, 7 figure