Non-Interactive Zero-Knowledge from Non-Interactive Batch Arguments

Zero-knowledge and succinctness are two important properties that arise in the study of non-interactive arguments. Previously, Kitagawa et al. (TCC 2020) showed how to obtain a non-interactive zero-knowledge (NIZK) argument for NP from a succinct non-interactive argument (SNARG) for NP. In particular, their work demonstrates how to leverage the succinctness property from an argument system and transform it into a zero-knowledge property. In this work, we study a similar question of leveraging succinctness for zero-knowledge. Our starting point is a batch argument for NP, a primitive that allows a prover to convince a verifier of $T$ NP statements $x_1, \ldots, x_T$ with a proof whose size scales sublinearly with $T$. Unlike SNARGs for NP, batch arguments for NP can be built from group-based assumptions in both pairing and pairing-free groups and from lattice-based assumptions. The challenge with batch arguments is that the proof size is only amortized over the number of instances, but can still encode full information about the witness to a small number of instances. We show how to combine a batch argument for NP with a local pseudorandom generator (i.e., a pseudorandom generator where each output bit only depends on a small number of input bits) and a dual-mode commitment scheme to obtain a NIZK for NP. Our work provides a new generic approach of realizing zero-knowledge from succinctness and highlights a new connection between succinctness and zero-knowledge

Securely Sampling Biased Coins with Applications to Differential Privacy

We design an efficient method for sampling a large batch of $d$ independent coins with a given bias $p \in [0,1]$. The folklore secure computation method for doing so requires $O(\lambda + \log d)$ communication and computation per coin to achieve total statistical difference $2^{-\lambda}$. We present an exponential improvement over the folklore method that uses just $O(\log(\lambda+\log d))$ gates per coin when sampling $d$ coins with total statistical difference $2^{-\lambda}$. We present a variant of our work that also concretely beats the folklore method for $\lambda \geq 60$ which are parameters that are often used in practice. Our new technique relies on using specially designed oblivious data structures to achieve biased coin samples that takean expected $2$ random bits to sample. Using our new sampling technique, we present an implementation of the differentially private report-noisy-max mechanism (a more practical implementation of the celebrated exponential mechanism) as a secure multi-party computation. Our benchmarks show that one can run this mechanism on a domain of size $d=2^{12}$ in 6 seconds and up to $d=2^{19}$ in 14 minutes. As far as we know, this is the first complete distributed implementation of either of these mechanisms

Estimating Development Cost of an Interactive Website Based Cancer Screening Promotion Program

Author's manuscript made available in accordance with the publisher's policy.Objectives The aim of this study was to estimate the initial development costs for an innovative talk show format tailored intervention delivered via the interactive web, for increasing cancer screening in women 50–75 who were non-adherent to screening guidelines for colorectal cancer and/or breast cancer. Methods The cost of the intervention development was estimated from a societal perspective. Micro costing methods plus vendor contract costs were used to estimate cost. Staff logs were used to track personnel time. Non-personnel costs include all additional resources used to produce the intervention. Results Development cost of the interactive web based intervention was $.39 million, of which 77% was direct cost. About 98% of the cost was incurred in personnel time cost, contract cost and overhead cost. Conclusions The new web-based disease prevention medium required substantial investment in health promotion and media specialist time. The development cost was primarily driven by the high level of human capital required. The cost of intervention development is important information for assessing and planning future public and private investments in web-based health promotion interventions

Process outcomes from a randomized controlled trial comparing tailored mammography interventions delivered via telephone versus DVD

Objective Tailored, interactive mammography-promotion interventions can increase adherence if women are exposed to and find them usable. We compare exposure to and usability of interventions delivered via telephone vs. DVD. Methods Process evaluation measures from 926 women randomly assigned to telephone or DVD intervention and completing post-intervention surveys. Results ∼83% of each group reported exposure to all content. Partial exposure was higher for DVD (9% vs. 0.4%; p < .01); no exposure was higher for phone (15% vs. 8%; p < .01). There were no differences in exposure by age or race. Full phone exposure was less likely for women who already made mammography appointments. Usability rating was higher for DVD (p < .05), driven by ratings of understandability and length. Usability of both interventions was correlated with lower baseline barriers, and higher fear, benefits, and self efficacy. Higher ratings for phone were associated with lower knowledge and contemplating mammography. Non-whites rated DVD better than whites. Conclusion Both tailored interactive interventions had wide reach and favorable ratings, but DVD recipients had greatest exposure to at least partial content and more favorable ratings, especially among non-white women. Practice implications This first evaluation of a tailored, interactive DVD provides promise for its use in mammography promotion

Promoting Colorectal Cancer Screening Discussion: A Randomized Controlled Trial

Background Provider recommendation is a predictor of colorectal cancer (CRC) screening. Purpose To compare the effects of two clinic-based interventions on patient–provider discussions about CRC screening. Design Two-group RCT with data collected at baseline and 1 week post-intervention. Setting/participants African-American patients that were non-adherent to CRC screening recommendations (n=693) with a primary care visit between 2008 and 2010 in one of 11 urban primary care clinics. Intervention Participants received either a computer-delivered tailored CRC screening intervention or a nontailored informational brochure about CRC screening immediately prior to their primary care visit. Main outcome measures Between-group differences in odds of having had a CRC screening discussion about a colon test, with and without adjusting for demographic, clinic, health literacy, health belief, and social support variables, were examined as predictors of a CRC screening discussion using logistic regression. Intervention effects on CRC screening test order by PCPs were examined using logistic regression. Analyses were conducted in 2011 and 2012. Results Compared to the brochure group, greater proportions of those in the computer-delivered tailored intervention group reported having had a discussion with their provider about CRC screening (63% vs 48%, OR=1.81, p<0.001). Predictors of a discussion about CRC screening included computer group participation, younger age, reason for visit, being unmarried, colonoscopy self-efficacy, and family member/friend recommendation (all p-values <0.05). Conclusions The computer-delivered tailored intervention was more effective than a nontailored brochure at stimulating patient–provider discussions about CRC screening. Those who received the computer-delivered intervention also were more likely to have a CRC screening test (fecal occult blood test or colonoscopy) ordered by their PCP

Distinctive Responsiveness to Stromal Signaling Accompanies Histologic Grade Programming of Cancer Cells

Whether stromal components facilitate growth, invasion, and dissemination of cancer cells or suppress neoplastic lesions from further malignant progression is a continuing conundrum in tumor biology. Conceptualizing a dynamic picture of tumorigenesis is complicated by inter-individual heterogeneity. In the post genomic era, unraveling such complexity remains a challenge for the cancer biologist. Towards establishing a functional association between cellular crosstalk and differential cancer aggressiveness, we identified a signature of malignant breast epithelial response to stromal signaling. Proximity to fibroblasts resulted in gene transcript alterations of >2-fold for 107 probes, collectively designated as Fibroblast Triggered Gene Expression in Tumor (FTExT). The hazard ratio predicted by the FTExT classifier for distant relapse in patients with intermediate and high grade breast tumors was significant compared to routine clinical variables (dataset 1, n = 258, HR – 2.11, 95% CI 1.17–3.80, p-value 0.01; dataset 2, n = 171, HR - 3.07, 95% CI 1.21–7.83, p-value 0.01). Biofunctions represented by FTExT included inflammatory signaling, free radical scavenging, cell death, and cell proliferation. Unlike genes of the ‘proliferation cluster’, which are overexpressed in aggressive primary tumors, FTExT genes were uniquely repressed in such cases. As proof of concept for our correlative findings, which link stromal-epithelial crosstalk and tumor behavior, we show a distinctive differential in stromal impact on prognosis-defining functional endpoints of cell cycle progression, and resistance to therapy-induced growth arrest and apoptosis in low vs. high grade cancer cells. Our experimental data thus reveal aspects of ‘paracrine cooperativity’ that are exclusively contingent upon the histopathologically defined grade of interacting tumor epithelium, and demonstrate that epithelial responsiveness to the tumor microenvironment is a deterministic factor underlying clinical outcome. In this light, early attenuation of epithelial-stromal crosstalk could improve the management of cases prone to be clinically challenging

Predictors of stage of adoption for colorectal cancer screening among African American primary care patients

BACKGROUND: Compared with other racial groups, African Americans have the highest colorectal cancer (CRC) incidence and mortality rates coupled with lower screening rates. OBJECTIVE: Our study examined the predictors of stage of adoption for fecal occult blood testing (FOBT) and colonoscopy among African American primary care patients who were nonadherent to published screening guidelines. METHODS: Baseline data (N = 815) in a randomized clinical trial were analyzed. Participants were categorized into precontemplation, contemplation, and preparation stages for FOBT and colonoscopy. Predictor variables were demographics, clinical variables, CRC health beliefs and knowledge, and social support. Hierarchical modeling was to identify significant predictors of stage of adoption. RESULTS: Older, male, Veterans Affairs participants and those with higher perceived self-efficacy, family/friend encouragement, and a provider recommendation had higher odds of being at a more advanced stage of adoption for FOBT. Patients with a history of cancer and higher perceived barriers had higher odds of being at an earlier stage of adoption for FOBT. Predictors of more advanced stage of adoption for colonoscopy included higher perceived benefits, higher perceived self-efficacy, family/friend encouragement, and a provider recommendation for colonoscopy. Higher income (>30 000 vs <15 000) was predictive of earlier stage of adoption for colonoscopy. CONCLUSIONS: Enhancing self-efficacy, encouragement from family and friends, and provider recommendations are important components of interventions to promote CRC screening. IMPLICATIONS FOR PRACTICE: Nurses can use knowledge of the characteristics associated with stage of adoption to educate and motivate their African American primary care patients to complete CRC screening tests

Phylogeography of Francisella tularensis subspecies holarctica from the country of Georgia

<p>Abstract</p> <p>Background</p> <p><it>Francisella tularensis</it>, the causative agent of tularemia, displays subspecies-specific differences in virulence, geographic distribution, and genetic diversity. <it>F. tularensis </it>subsp. <it>holarctica </it>is widely distributed throughout the Northern Hemisphere. In Europe, <it>F. tularensis </it>subsp. <it>holarctica </it>isolates have largely been assigned to two phylogenetic groups that have specific geographic distributions. Most isolates from Western Europe are assigned to the B.Br.FTNF002-00 group, whereas most isolates from Eastern Europe are assigned to numerous lineages within the B.Br.013 group. The eastern geographic extent of the B.Br.013 group is currently unknown due to a lack of phylogenetic knowledge about populations at the European/Asian juncture and in Asia. In this study, we address this knowledge gap by describing the phylogenetic structure of <it>F. tularensis </it>subsp. <it>holarctica </it>isolates from the country of Georgia, and by placing these isolates into a global phylogeographic context.</p> <p>Results</p> <p>We identified a new genetic lineage of <it>F. tularensis </it>subsp. <it>holarctica </it>from Georgia that belongs to the B.Br.013 group. This new lineage is genetically and geographically distinct from lineages previously described from the B.Br.013 group from Central-Eastern Europe. Importantly, this new lineage is basal within the B.Br.013 group, indicating the Georgian lineage diverged before the diversification of the other known B.Br.013 lineages. Although two isolates from the Georgian lineage were collected nearby in the Ukrainian region of Crimea, all other global isolates assigned to this lineage were collected in Georgia. This restricted geographic distribution, as well as the high levels of genetic diversity within the lineage, is consistent with a relatively older origin and localized differentiation.</p> <p>Conclusions</p> <p>We identified a new lineage of <it>F. tularensis </it>subsp. <it>holarctica </it>from Georgia that appears to have an older origin than any other diversified lineages previously described from the B.Br.013 group. This finding suggests that additional phylogenetic studies of <it>F. tularensis </it>subsp. <it>holarctica </it>populations in Eastern Europe and Asia have the potential to yield important new insights into the evolutionary history and phylogeography of this broadly dispersed <it>F. tularensis </it>subspecies.</p

Interventions to Promote Colorectal Cancer Screening in Primary Care: Results of a Randomized Trial

poster abstractAims: The purpose of this randomized trial was to compare rates of self-reported colorectal cancer (CRC) screening and forward movement in stage of adoption at 6 months post-intervention. African American primary care patients (n=595) who were eligible for CRC screening were randomly assigned to receive a computer-delivered tailored CRC screening intervention (n=286) or a non-tailored screening brochure (n=309) prior to their scheduled visit with their primary care provider. Hypotheses were that differences between groups would be observed in proportions of patients who: 1) completed fecal occult blood tests (FOBT) or colonoscopy; and 2) had moved forward in stages of adoption for these tests. Methods: Participants completed baseline and 6-month telephone interviews; interventions were delivered prior to primary care provider visits. Differences between groups were examined using chi-square tests, predictors of screening were determined using logistic regression models. Results: In the computer-tailored group, the FOBT completion rate was 12.6% compared to 7.8% in the brochure group (p=0.05). The colonoscopy completion rate was 17.5% in the computer group vs. 15.2% in the brochure group (p=0.45). Forward stage movement for FOBT was observed in 28.4% of the computer groups vs. 20.8% in the brochure group (p=0.03). Forward stage movement for colonoscopy was 38.5% in the computer group and 36.8% (p=0.68) in each group, respectively. Conclusions: The computer-tailored intervention was more effective than the brochure at increasing FOBT completion and movement toward action. More research is needed to explain why the tailored intervention was not more effective at increasing colonoscopy completion and to identify moderators of intervention efficacy