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

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

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

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

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

Development and Control of Biofilms: Novel Strategies Using Natural Antimicrobials

Separation membranes have a wide application in the food industry, for instance, in the clarification/fractionation of milk, the concentration/separation of selected components, and wastewater treatment. They provide a large area for bacteria to attach and colonize. When a product comes into contact with a membrane, it initiates bacterial attachment/colonization and eventually forms biofilms. Several cleaning and sanitation protocols are currently utilized in the industry; however, the heavy fouling of the membrane over a prolonged duration affects the overall cleaning efficiency. In view of this, alternative approaches are being developed. Therefore, the objective of this review is to describe the novel strategies for controlling membrane biofilms such as enzyme-based cleaner, naturally produced antimicrobials of microbial origin, and preventing biofilm development using quorum interruption. Additionally, it aims to report the constitutive microflora of the membrane and the development of the predominance of resistant strains over prolonged usage. The emergence of predominance could be associated with several factors, of which, the release of antimicrobial peptides by selective strains is a prominent factor. Therefore, naturally produced antimicrobials of microbial origin could thus provide a promising approach to control biofilms. Such an intervention strategy could be implemented by developing a bio-sanitizer exhibiting antimicrobial activity against resistant biofilms

Incorporation of Probiotics and Other Functional Ingredients in Dairy Fat-Rich Products: Benefits, Challenges, and Opportunities

This review focuses on the potential opportunities to incorporate functional ingredients like probiotics in the dairy fat-rich matrix to develop functional foods. Many dietary guidelines and the relevant literature have in general indicated many benefits of consuming milk-fat-rich products for the human body. Milk fat contains essential nutrients, including fat-soluble vitamins; short-, medium-, and long-chain with odd and branched chain fatty acids; essential amino acids; and calcium, which are all known for their bioactive properties. In addition, the incorporation of probiotics, which are known for their bioactive properties, could further enhance the products’ attributes. However, direct probiotic addition is known to encounter viability challenges during manufacturing and storage. There is thus an opportunity to introduce a value-added range of dairy fat-rich products imparting bioactive and functional benefits. The current review is an attempt to consolidate information in this area and explore further avenues for the value addition of dairy fat-rich products

Ultrasound-Assisted Cavitation Effect on the Biofilm-Forming Ability of Common Dairy Sporeformers

Thermoduric sporeformers survive heat treatment and can form biofilm on contact food surfaces that is difficult to clean and may cause cross contamination to milk products. It was hypothesized that cavitation would influence sporeformers’ ability to attach to contact surfaces and form biofilm. Common dairy sporeformers of Geobacillus stearothermophilus, Bacillus licheniformis, and Bacillus sporothermodurans were individually inoculated in sterile skim milk at the levels of 6.0 log CFU/mL. Inoculated samples were treated by cavitation at 80% amplitudes for 10 min each. Pre and post samples were used to develop biofilms on stainless steel coupons under static conditions. Scanning electron micrograph was used to observe the developed biofilms. All the experiments were conducted in triplicate and were statistically analyzed using a t test. The average counts of spiked milk samples were 7.2, 8.0, and 7.7 logs CFU/mL, respectively, for the three sporeformers. Post-cavitation counts were reduced significantly to 3.4, 4.2, and 3.7 logs CFU/mL, respectively. Pre-cavitation biofilm counts of the three sporeformers were 5.35, 6.42, and 6.5 logs CFU/ cm2, respectively in 72 h. The three sporeformers’ biofilm showed significantly (p \u3c 0.05) lower counts after cavitation of 4.39, 5.44, and lower counts of 4.39 logs CFU/cm2, respectively, for the three organisms. The result showed that G. stearothermophilus formed the least biofilms among others after cavitation. Although the ultrasonication treatment reduced the number of sporeformer bacteria, the survivors still retained the ability to attach to the stainless-steel food contact surfaces

Incorporation of Probiotics and Other Functional Ingredients in Dairy Fat-Rich Products: Benefits, Challenges, and Opportunities

This review focuses on the potential opportunities to incorporate functional ingredients like probiotics in the dairy fat-rich matrix to develop functional foods. Many dietary guidelines and the relevant literature have in general indicated many benefits of consuming milk-fat-rich products for the human body. Milk fat contains essential nutrients, including fat-soluble vitamins; short-, medium-, and long-chain with odd and branched chain fatty acids; essential amino acids; and calcium, which are all known for their bioactive properties. In addition, the incorporation of probiotics, which are known for their bioactive properties, could further enhance the products’ attributes. However, direct probiotic addition is known to encounter viability challenges during manufacturing and storage. There is thus an opportunity to introduce a value-added range of dairy fat-rich products imparting bioactive and functional benefits. The current review is an attempt to consolidate information in this area and explore further avenues for the value addition of dairy fat-rich products