504 research outputs found

    The chaining lemma and its application

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    We present a new information-theoretic result which we call the Chaining Lemma. It considers a so-called “chain” of random variables, defined by a source distribution X(0)with high min-entropy and a number (say, t in total) of arbitrary functions (T1,…, Tt) which are applied in succession to that source to generate the chain (Formula presented). Intuitively, the Chaining Lemma guarantees that, if the chain is not too long, then either (i) the entire chain is “highly random”, in that every variable has high min-entropy; or (ii) it is possible to find a point j (1 ≤ j ≤ t) in the chain such that, conditioned on the end of the chain i.e. (Formula presented), the preceding part (Formula presented) remains highly random. We think this is an interesting information-theoretic result which is intuitive but nevertheless requires rigorous case-analysis to prove. We believe that the above lemma will find applications in cryptography. We give an example of this, namely we show an application of the lemma to protect essentially any cryptographic scheme against memory tampering attacks. We allow several tampering requests, the tampering functions can be arbitrary, however, they must be chosen from a bounded size set of functions that is fixed a prior

    Network analysis of PTSD and depressive symptoms in 158,139 treatment-seeking veterans with PTSD

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    Background In recent years, a new framework for analyzing and understanding posttraumatic stress disorder (PTSD) was introduced; the network approach. Up until now, network analysis studies of PTSD were largely conducted on small to medium sample sizes (N < 1,000), which might be a possible cause of variability in main findings. Moreover, only a limited number of network studies investigated comorbidity.Methods In this study, we utilized a large sample to conduct a network analysis of 17 symptoms of PTSD (DSM-IV), and compared it to the result of a second network consisting of symptoms of PTSD and depression (based on Patient Health Questionnaire-9 [PHQ-9]). Our sample consisted of 502,036 treatment-seeking veterans, out of which 158,139 had fully completed the assessment of symptoms of PTSD and a subsample of 32,841 with valid PCL and PHQ-9 that was administered within 14 days or less.Results Analyses found that in the PTSD network, the most central symptoms were feeling distant or cut off from others, followed by feeling very upset when reminded of the event, and repeated disturbing memories or thoughts of the event. In the combined network, we found that concentration difficulties and anhedonia are two of the five most central symptoms.Conclusion Our findings replicate the centrality of intrusion symptoms in PTSD symptoms' network. Taking into account the large sample and high stability of the network structure, we believe our study can answer some of the criticism regarding stability of cross-sectional network structures.Stress and Psychopatholog

    Predictable arguments of knowledge

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    We initiate a formal investigation on the power of predictability for argument of knowledge systems for NP. Specifically, we consider private-coin argument systems where the answer of the prover can be predicted, given the private randomness of the verifier; we call such protocols Predictable Arguments of Knowledge (PAoK). Our study encompasses a full characterization of PAoK, showing that such arguments can be made extremely laconic, with the prover sending a single bit, and assumed to have only one round (i.e., two messages) of communication without loss of generality. We additionally explore PAoK satisfying additional properties (including zero-knowledge and the possibility of re-using the same challenge across multiple executions with the prover), present several constructions of PAoK relying on different cryptographic tools, and discuss applications to cryptography

    Prevalence of monogenic diabetes amongst Polish children after a nationwide genetic screening campaign

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    Aims/hypothesis The aim of this study was to study dynamic changes in the prevalence of different types of diabetes in paediatric populations in Poland, with a specific focus on monogenic diabetes (MD). Methods Using epidemiologic data (PolPeDiab Collaboration) and nationwide genetic test results (TEAM Programme), we compared the prevalence of type 1, type 2 and cystic fibrosis-related diabetes (CFRD) and MD. Genetically confirmed MD included MODY, neonatal diabetes and Wolfram and Alström syndromes. The study covered all children aged 0-18 years treated for diabetes between 2005 and 2011 in three regions, inhabited by 23.7% (1,989,988) of Polish children, with a low prevalence of childhood obesity (<5%). Results The prevalence of type 1 diabetes showed a continuous increase, from 96 to 138/100,000 children. The prevalence of type 2 diabetes and CFRD also increased, from 0.3 to 1.01/100,000 children and from 0.1 to 0.95/100,000 children, respectively. The prevalence of MD was stable at between 4.2 and 4.6/100,000 children, accounting for 3.1-4.2% of children with diabetes, with glucokinase (GCK)-MODY being the most frequent type, amounting to 83% of patients with MD. The percentage of positive test results decreased with the number of referrals, suggesting that children with the highest probability of MD were referred initially, followed by those with a less clear-cut phenotype. The prevalence of neonatal diabetes equalled 1 in 300,000 children. Conclusions/interpretation The prevalence of MD in a paediatric population with a low prevalence of obesity remains stable and is nearly fivefold higher than that of type 2 diabetes and CFRD, justifying a need for increased access to genetic diagnostic procedures in diabetic children

    Ultrasound and clinical preoperative characteristics for discrimination between ovarian metastatic colorectal cancer and primary ovarian cancer: A case-control study

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    The aim of this study was to describe the clinical and sonographic features of ovarian metastases originating from colorectal cancer (mCRC), and to discriminate mCRC from primary ovarian cancer (OC). We conducted a multi-institutional, retrospective study of consecutive patients with ovarian mCRC who had undergone ultrasound examination using the International Ovarian Tumor Analysis (IOTA) terminology, with the addition of evaluating signs of necrosis and abdominal staging. A control group included patients with primary OC. Clinical and ultrasound data, subjective assessment (SA), and an assessment of different neoplasias in the adnexa (ADNEX) model were evaluated. Fisher's exact and Student's t-tests, the area under the receiver-operating characteristic curve (AUC), and classification and regression trees (CART) were used to conduct statistical analyses. In total, 162 patients (81 with OC and 81 with ovarian mCRC) were included. None of the patients with OC had undergone chemotherapy for CRC in the past, compared with 40% of patients with ovarian mCRC (p &lt; 0.001). The ovarian mCRC tumors were significantly larger, a necrosis sign was more frequently present, and tumors had an irregular wall or were fixed less frequently; ascites, omental cake, and carcinomatosis were less common in mCRC than in primary OC. In a subgroup of patients with ovarian mCRC who had not undergone treatment for CRC in anamnesis, tumors were larger, and had fewer papillations and more locules compared with primary OC. The highest AUC for the discrimination of ovarian mCRC from primary OC was for CART (0.768), followed by SA (0.735) and ADNEX calculated with CA-125 (0.680). Ovarian mCRC and primary OC can be distinguished based on patient anamnesis, ultrasound pattern recognition, a proposed decision tree model, and an ADNEX model with CA-125 levels

    Exploring the Potential of Sulfonamide-Dihydropyridine Hybrids as Multitargeted Ligands for Alzheimer’s Disease Treatment

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    Alzheimer’s disease (AD) is a multifactorial neurodegenerative disease that has a heavy social and economic impact on all societies and for which there is still no cure. Multitarget-directed ligands (MTDLs) seem to be a promising therapeutic strategy for finding an effective treatment for this disease. For this purpose, new MTDLs were designed and synthesized in three steps by simple and cost-efficient procedures targeting calcium channel blockade, cholinesterase inhibition, and antioxidant activity. The biological and physicochemical results collected in this study allowed us the identification two sulfonamide-dihydropyridine hybrids showing simultaneous cholinesterase inhibition, calcium channel blockade, antioxidant capacity and Nrf2-ARE activating effect, that deserve to be further investigated for AD therapy.This work was supported by the Regional Council of Franche-Comté (2022Y-13659 and 13660 Accurate Project).Peer reviewe

    On the Query Complexity of Constructing PRFs from Non-adaptive PRFs

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    This paper studies constructions of pseudorandom functions (PRFs) from non-adaptive PRFs (naPRFs), i.e., PRFs which are secure only against distinguishers issuing all of their queries at once. Berman and Haitner (Journal of Cryptology, \u2715) gave a one-call construction which, however, is not hardness preserving -- to obtain a secure PRF (against polynomial-time distinguishers), they need to rely on a naPRF secure against superpolynomial-time distinguishers; in contrast, all known hardness-preserving constructions require ω(1)\omega(1) calls. This leaves open the question of whether a stronger superpolynomial-time assumption is necessary for one-call (or constant-call) approaches. Here, we show that a large class of one-call constructions (which in particular includes the one of Berman and Haitner) cannot be proved to be a secure PRF under a black-box reduction to the (polynomial-time) naPRF security of the underlying function. Our result complements existing impossibility results (Myers, EUROCRYPT \u2704; Pietrzak, CRYPTO \u2705) ruling out natural specific approaches, such as parallel and sequential composition. Furthermore, we show that our techniques extend to rule out a natural class of constructions making parallel but arbitrary number of calls which in particular includes parallel composition and the two-call, cuckoo-hashing based construction of Berman et al.\ (Journal of Cryptology, \u2719)

    Transferrin changes in haemodialysed patients

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    Transferrin (Tf) is a glycoprotein responsible for iron transport in the human body. Physiologically in reaction with Concanavalin A, Tf occurs in four distinct variants Tf1, Tf2, Tf3 (apo-Tf) and Tf4. It was reported recently that Tf is changing, particularly during acute phase response, taking place among others in end-stage renal disease. In this study, we wanted to find the answer to three main questions: firstly, how Tf is changing in patients treated with maintenance haemodialysis (mHD), secondly, whether there are any Tf changes in the course of mHD treatment, and thirdly, what factors can affect Tf microheterogeneity in these patients. Studies were performed on 80 haemodialysed patients and 21 healthy volunteers. The Tf concentration was determined by the rocket immunoelectrophoresis, and its microheterogeneity was assessed by the ConA crossed immunoaffinity electrophoresis. During the annual observation of the distribution of the Tf variants, we have found both changes of the percentage contents of all Tf variants in the whole Tf concentration and a significant decrease in Tf2, Tf3 and Tf4 serum concentrations. Moreover, we found that decrease in the renal function, duration of mHD, and inflammation may contribute to these above-mentioned changes, which are probably the factors that should be taken into account when explaining the mechanisms of persistence of anaemia in haemodialysed patients

    Effect of BDNF Val66Met on memory decline and hippocampal atrophy in prodromal alzheimer\u27s disease: A preliminary study

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    Objective: Cross-sectional genetic association studies have reported equivocal results on the relationship between the brain-derived neurotrophic factor (BDNF) Val66Met and risk of Alzheimer\u27s disease (AD). As AD is a neurodegenerative disease, genetic influences may become clearer from prospective study. We aimed to determine whether BDNF Val66Met polymorphism influences changes in memory performance, hippocampal volume, and Aβ accumulation in adults with amnestic mild cognitive impairment (aMCI) and high Aβ. Methods: Thirty-four adults with aMCI were recruited from the Australian, Imaging, Biomarkers and Lifestyle (AIBL) Study. Participants underwent PiB-PET and structural MRI neuroimaging, neuropsychological assessments and BDNF genotyping at baseline, 18 month, and 36 month assessments. Results: In individuals with aMCI and high Aβ, Met carriers showed significant and large decline in episodic memory (d = 0.90, p = .020) and hippocampal volume (d = 0.98, p = .035). BDNF Val66Met was unrelated to the rate of Aβ accumulation (d = -0.35, p = .401). Conclusions: Although preliminary due to the small sample size, results of this study suggest that high Aβ levels and Met carriage may be useful prognostic markers of accelerated decline in episodic memory, and reductions in hippocampal volume in individuals in the prodromal or MCI stage of AD

    Recent Change—North Sea

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    This chapter discusses past and ongoing change in the following physical variables within the North Sea: temperature, salinity and stratification; currents and circulation; mean sea level; and extreme sea levels. Also considered are carbon dioxide; pH and nutrients; oxygen; suspended particulate matter and turbidity; coastal erosion, sedimentation and morphology; and sea ice. The distinctive character of the Wadden Sea is addressed, with a particular focus on nutrients and sediments. This chapter covers the past 200 years and focuses on the historical development of evidence (measurements, process understanding and models), the form, duration and accuracy of the evidence available, and what the evidence shows in terms of the state and trends in the respective variables. Much work has focused on detecting long-term change in the North Sea region, either from measurements or with models. Attempts to attribute such changes to, for example, anthropogenic forcing are still missing for the North Sea. Studies are urgently needed to assess consistency between observed changes and current expectations, in order to increase the level of confidence in projections of expected future conditions
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