Optimal Lower Bounds for Universal and Differentially Private Steiner Tree and TSP

Given a metric space on n points, an {\alpha}-approximate universal algorithm for the Steiner tree problem outputs a distribution over rooted spanning trees such that for any subset X of vertices containing the root, the expected cost of the induced subtree is within an {\alpha} factor of the optimal Steiner tree cost for X. An {\alpha}-approximate differentially private algorithm for the Steiner tree problem takes as input a subset X of vertices, and outputs a tree distribution that induces a solution within an {\alpha} factor of the optimal as before, and satisfies the additional property that for any set X' that differs in a single vertex from X, the tree distributions for X and X' are "close" to each other. Universal and differentially private algorithms for TSP are defined similarly. An {\alpha}-approximate universal algorithm for the Steiner tree problem or TSP is also an {\alpha}-approximate differentially private algorithm. It is known that both problems admit O(logn)-approximate universal algorithms, and hence O(log n)-approximate differentially private algorithms as well. We prove an {\Omega}(logn) lower bound on the approximation ratio achievable for the universal Steiner tree problem and the universal TSP, matching the known upper bounds. Our lower bound for the Steiner tree problem holds even when the algorithm is allowed to output a more general solution of a distribution on paths to the root.Comment: 14 page

ROLE OF MITOCHONDRIA DURING BOVINE ADENOVIRUS 3 INFECTION

Bovine adenovirus (BAdV) -3 is a non-enveloped, icosahedral virus with a double-stranded DNA genome, and is being developed as a vector for vaccination of animals and humans. Mitochondria are multifunctional organelles, which are involved in various functions of the cell including but not limited to energy production, aging, regulation of cell cycle, anti viral responses. Thus, this makes them strategic targets for many pathogens. Although a number of viruses affect the structure and function of mitochondria, the effect of BAdV-3 infection on these organelles has not been well characterized. The aim of the present study was to ascertain the pathological effects of BAdV-3 infection on host mitochondria and the role of BAdV-3 encoded proteins in modulating mitochondrial functions. Electron microscopy analysis revealed extensive damage to the inner mitochondrial membrane characterized by dissolution of cristae and amorphous appearance of mitochondrial matrix with little or no damage to the outer mitochondrial membrane. There were fewer cristae with altered morphology. Patches of protein synthesis machinary around mitochondria were observed at 12 hrs post infection. At 24 hrs post-infection, extensive damage to mitochondria was evident throughout the infected cell. ATP production, mitochondrial Ca2+ and mitochondrial membrane potential (MMP) peaked at 18 hrs post-infection but decreased significantly at 24 hrs post-infection. This decrease coincided with increased production of superoxide (SO) and reactive oxygen species (ROS), at 24 hrs post-infection indicating acute oxidative stress in the cells and suggesting a complete failure of the cellular homeostatic machinary. Sequence analysis of BAdV-3 proteins revealed the presence of potential mitochodria localization signals (MLS) in 52K, VII, 33/22K and IVa2. Western blot analysis of isolated mitochondrial fractions suggested that all these proteins are localized in the mitochondria. However, a more stringent proteinase K assay confirmed the presence of 52K and pVII in the mitochondria suggesting that the other observed proteins were loosely attached to the surface of the mitochondria or may simple co-purify with the mitochondrial fraction. The presence of potential MLS in 52K and pVII was confirmed by localization of EYFP (Enhanced Yellow Fluorescent Protein; a predominantly cytoplasmic protein), when fused to MLS of pVII or 52K, to mitochondria of transfected cells. Expression of pVII in transfected cells showed an increase in MMP and ATP production, and increased sequestration / retention of mitochondrial Ca2+ in the cells. However, there was no increase in reactive oxygen species (ROS) / superoxide (SO) production in pVII transfected cells indicating that pVII acts as an antiapototic protein. In contrast, expression of 52K in transfected cells significantly increased ROS/SO production with no significant change in ATP production, mitochondrial Ca2+ or MMP indicating that 52K alone causes an oxidative stress in cells following infection and causes apoptosis. In conclusion, these results reveal an intricate relationship between Ca2+ homeostasis, the ATP generation ability of cells, SO and ROS production and regulation of MMP following infection by BAdV-3 or transfection of the cells with plasmid DNAs expressing pVII & 52K. While pVII appears to contribute to the survival of the cells during virus replication, 52K is involved in the death of the infected cells and thus may help in release of progeny virus

Canadian Graduate Legal Education: Past, Present and Future

Canadian graduate legal education has seldom been the subject of scholarly inquiry This article seeks to fill the vacuum by describing and evaluating various features associated with master s and doctoral programs offered by the nation s /ao schools. A number of criteria are used in this analysis, some of which have been garnered from the broader literature on higher education The article concludes with a series of specific programmatic and policy reform proposals aimed at strengthening the state of graduate legal education in this countr

Extended hierarchical search (EHS) algorithm for detection of gravitational waves from inspiraling compact binaries

Pattern matching techniques like matched filtering will be used for online extraction of gravitational wave signals buried inside detector noise. This involves cross correlating the detector output with hundreds of thousands of templates spanning a multi-dimensional parameter space, which is very expensive computationally. A faster implementation algorithm was devised by Mohanty and Dhurandhar [1996] using a hierarchy of templates over the mass parameters, which speeded up the procedure by about 25 to 30 times. We show that a further reduction in computational cost is possible if we extend the hierarchy paradigm to an extra parameter, namely, the time of arrival of the signal. In the first stage, the chirp waveform is cut-off at a relatively low frequency allowing the data to be coarsely sampled leading to cost saving in performing the FFTs. This is possible because most of the signal power is at low frequencies, and therefore the advantage due to hierarchy over masses is not compromised. Results are obtained for spin-less templates up to the second post-Newtonian (2PN) order for a single detector with LIGO I noise power spectral density. We estimate that the gain in computational cost over a flat search is about 100.Comment: 6 pages, 6 EPS figures, uses CQG style iopart.cl

Dynamic Channel Allocation in Mobile Multimedia Networks Using Error Back Propagation and Hopfield Neural Network (EBP-HOP)

AbstractIn mobile multimedia communication systems, the limited bandwidth is an issue of serious concern. However for the better utilization of available resources in a network, channel allocation scheme plays a very important role to manage the available resources in each cell. Hence this issue should be managed to reduce the call blocking or dropping probabilities. This paper gives the new dynamic channel allocation scheme which is based on handoff calls and traffic mobility using hopfield neural network. It will improve the capacity of existing system. Hopfield method develops the new energy function that allocates channel not only for new call but also for handoff calls on the basis of traffic mobility information. Moreover, we have also examined the performance of traffic mobility with the help of error back propagation neural network model to enhance the overall Quality of Services (QoS) in terms of continuous service availability and intercell handoff calls. Our scheme decreases the call handoff dropping and blocking probability up to a better extent as compared to the other existing systems of static and dynamic channel allocation schemes

Waste Algae for Bioenergy Generation to Mitigate Eutrophication and Greenhouse Emissions in Water Bodies

Eutrophication has a significant negative impact on the ecosystem since it depletes the planet's biological resources and is further responsible for climate change. It is caused by both endogenous and exogenous nutrient enrichment. This phenomenon degrades the water quality and simultaneously increases the greenhouse gases emission from waterbodies resulting in climate change Inland waterbodies contain enormous amounts of nutrients such as phosphorous, nitrogen, and carbon. Thus, it becomes essential to restore these nutrients using proper sustainable approaches. Algae-based technologies have received a lot of attention these days because of environmentally friendly and inexpensive treatment. About 70% of the nutrient load from wastewater can be removed using such technology. The recovered algal biomass after wastewater treatment contains various biomolecules which can be used for the producing of value-added products such as bioenergy in the form of biomethane and biodiesel, cosmetics and pharmaceuticals along with the synthesis of nanoparticles. Therefore, the primary goal of this review is to inform readers about the possibilities of a low-cost integrated biorefinery based on microalgae for resource recovery and to mitigate eutrophication and greenhouse gas emission from water bodies

The RSSearch™ Registry: patterns of care and outcomes research on patients treated with stereotactic radiosurgery and stereotactic body radiotherapy

Background: The RSSearch™ Registry is a multi-institutional, observational, ongoing registry established to standardize data collection from patients treated with stereotactic radiosurgery (SRS) and/or stereotactic body radiotherapy (SBRT). This report describes the design, patient demographics, lesion characteristics, and SRS/SBRT treatment patterns in RSSearch™. Illustrative patient-related outcomes are also presented for two common treatment sites – brain metastases and liver metastases. Materials and methods Thirty-nine US centers participated in RSSearch™. Patients screened for SRS/SBRT were eligible to be enrolled. Descriptive analyses were performed to assess patient characteristics, physician treatment practices, and clinical outcomes. Kaplan-Meier analysis was used to determine overall survival (OS), local progression-free (LPFS), and distant disease-free survival (DDFS). Results: From January, 2008 – January, 2013, 11,457 patients were enrolled. The median age was 67 years (range 7–100 years); 51% male and 49% female. Forty-six percent had no prior treatment, 22% had received chemotherapy, 19% radiation therapy and 17% surgery. There were 11,820 lesions from 65 treatment locations; 54% extracranial and 46% intracranial. The most common treatment locations were brain/cranial nerve/spinal cord, lung, prostate and liver. Metastatic lesions accounted for the majority of cases (41.6%), followed by primary malignant (32.9%), benign (10.9%), recurrent (9.4%), and functional diseases (4.3%). SRS/SBRT was used with a curative intent in 39.8% and palliative care in 44.8% of cases. The median dose for all lesions was 30 Gy (range 70, OS was 11 months vs. 4 months for KPS ≤ 70. Six-month and 12-month local control was 79% and 61%, respectively for patients with KPS ≤ 70, and 85% and 74%, respectively for patients with KPS > 70. In a second subset analysis including 174 patients with 204 liver metastases, median OS was 22 months. At 1-year, LPFS and DDFS rates were 74% and 53%, respectively. LPFS. Conclusion: This study demonstrates that collective patterns of care and outcomes research for SRS/SBRT can be performed and reported from data entered by users in a common database. The RSSearch™ dataset represents SRS/SBRT practices in a real world setting, providing a useful resource for expanding knowledge of SRS/SBRT treatment patterns and outcomes and generating robust hypotheses for randomzed clinical studies

Control of sulphur and minimisation of centre line segregation for Rail Steel

Rail is the most important constituent of the track structure and plays a very vital role in the reliability of railway system as a whole. Quality of rail steel with reference to its chemical composition has been a matter of prime importance for the manufacturers as well as Railways. Sulphur is a detrimental element in rails since it causes hot shortness during rolling, centerline segregation during casting, poor weldability for the rails etc. To improve quality of rails, a substantially low range of sulphur < 0.015% (Railway's specified norms <0.03%) has been targeted in Bhilai Steel Plant by adequate sulphur control measures in steelmaking process. A two stage desulphurisation treatment is now employed in which the blast furnace hot metal is first treated by co-injection of Mg and CaC reagents, and subsequent treatment with a 2 synthetic slag former (CaO-Al O ) added to the ladle during tapping from the Basic 2 3 Oxygen furnace. Improvement in the internal quality of the cast bloom has been established by introduction of Electro Magnetic Stirring. The centerline segregation is minimized vis-a-vis the properties of the cast product and rails improved by the successful implementation of step by step control measures