On the Degree-Insensitive SI-GDH problem and assumption

Fujioka, Takashima, Terada and Yoneyama, in their 2018 work on an authenticated key exchange protocol using supersingular isogenies, use new assumptions in their security proof of the scheme. In particular, they define the degree-sensitive and degree-insensitive SI-GDH assumptions and problems. These assumptions include a decision oracle that is used in the security proofs. We give evidence that those assumptions are not well defined. Hence, the security proofs in their paper do not seem to be correct

Post-Quantum Signal Key Agreement with SIDH

In the effort to transition cryptographic primitives and protocols to quantum-resistant alternatives, an interesting and useful challenge is found in the Signal protocol. The initial key agreement component of this protocol, called X3DH, has so far proved more subtle to replace - in part due to the unclear security model and properties the original protocol is designed for. This paper defines a formal security model for the original signal protocol, in the context of the standard eCK and CK+ type models, which we call the Signal-adapted-CK model. We then propose a secure replacement for the Signal X3DH key exchange protocol based on SIDH, and provide a proof of security in the Signal-adapted-CK model, showing our protocol satisfies all security properties of the original Signal X3DH. We call this new protocol SI-X3DH. Our protocol refutes the claim of Brendel, Fischlin, Günther, Janson, and Stebila [Selected Areas in Cryptography (2020)] that SIDH cannot be used to construct a secure X3DH replacement due to adaptive attacks. Unlike the generic constructions proposed in the literature, our protocol achieves deniability without expensive machinery such as post-quantum ring signatures. It also benefits from the efficiency of SIDH as a key-exchange protocol, compared to other post-quantum key exchange protocols such as CSIDH

The association between individual counselling and health behaviour change: the See Kidney Disease (SeeKD) targeted screening programme for chronic kidney disease

Background: Health behaviour change is an important component of management for patients with chronic kidney disease (CKD); however, the optimal method to promote health behaviour change for self-management of CKD is unknown. The See Kidney Disease (SeeKD) targeted screening programme screened Canadians at risk for CKD and promoted health behaviour change through individual counselling and goal setting. Objectives: The objectives of this study are to determine the effectiveness of individual counselling sessions for eliciting behaviour change and to describe participant characteristics associated with behaviour change. Design: This is a cross-sectional, descriptive study. Setting: The study setting is the National SeeKD targeted screening programme. Patients: The participants are all ‘at risk’ patients who were screened for CKD and returned a follow-up health behaviour survey ( n = 1129). Measurements: Health behaviour change was defined as a self-reported change in lifestyle, including dietary changes or medication adherence. Methods: An individual counselling session was provided to participants by allied healthcare professionals to promote health behaviour change. A survey was mailed to all participants at risk of CKD within 2-4 weeks following the screening event to determine if behaviour changes had been initiated. Descriptive statistics were used to describe respondent characteristics and self-reported behaviour change following screening events. Results were stratified by estimated glomerular filtration rate (eGFR) (60 mL/min/1.73 m 2 ). Log binomial regression analysis was used to determine the predictors of behaviour change. Results: Of the 1129 respondents, the majority (89.8 %) reported making a health behaviour change after the screening event. Respondents who were overweight (body mass index [BMI] 25-29.9 kg/m 2 ) or obese (BMi ≥ 30.0 kg/m 2 ) were more likely to report a behaviour change (prevalence rate ratio (PRR) 0.66, 95 % confidence interval (CI) 0.44-0.99 and PRR 0.49, 95 % CI 0.30-0.80, respectively). Further, participants with a prior intent to change their behaviour were more likely to make a behaviour change (PRR 0.58, 95 % CI 0.35-0.96). Results did not vary by eGFR category. Limitations: We are unable to determine the effectiveness of the behaviour change intervention given the lack of a control group. Potential response bias and social desirability bias must also be considered when interpreting the study findings. Conclusions: Individual counselling and goal setting provided at screening events may stimulate behaviour change amongst individuals at risk for CKD. However, further research is required to determine if this behaviour change is sustained and the impact on CKD progression and outcomes

Carbon burial in deep-sea sediment and implications for oceanic inventories of carbon and alkalinity over the last glacial cycle

Although it has long been assumed that the glacial–interglacial cycles of atmospheric CO2 occurred due to increased storage of CO2 in the ocean, with no change in the size of the “active” carbon inventory, there are signs that the geological CO2 supply rate to the active pool varied significantly. The resulting changes of the carbon inventory cannot be assessed without constraining the rate of carbon re- moval from the system, which largely occurs in marine sed- iments. The oceanic supply of alkalinity is also removed by the burial of calcium carbonate in marine sediments, which plays a major role in air–sea partitioning of the active carbon inventory. Here, we present the first global reconstruction of carbon and alkalinity burial in deep-sea sediments over the last glacial cycle. Although subject to large uncertainties, the reconstruction provides a first-order constraint on the effects of changes in deep-sea burial fluxes on global carbon and alkalinity inventories over the last glacial cycle. The results suggest that reduced burial of carbonate in the Atlantic Ocean was not entirely compensated by the increased burial in the Pacific basin during the last glacial period, which would have caused a gradual buildup of alkalinity in the ocean. We also consider the magnitude of possible changes in the larger but poorly constrained rates of burial on continental shelves, and show that these could have been significantly larger than the deep-sea burial changes. The burial-driven inventory variations are sufficiently large to have significantly altered the δ13C of the ocean–atmosphere carbon and changed the aver- age dissolved inorganic carbon (DIC) and alkalinity concentrations of the ocean by more than 100 μM, confirming that carbon burial fluxes were a dynamic, interactive component of the glacial cycles that significantly modified the size of the active carbon pool. Our results also suggest that geolog- ical sources and sinks were significantly unbalanced during the late Holocene, leading to a slow net removal flux on the order of 0.1 PgC yr−1 prior to the rapid input of carbon dur- ing the industrial period

SIDH Proof of Knowledge

We show that the soundness proof for the De Feo-Jao-Plut identification scheme (the basis for supersingular isogeny Diffie--Hellman (SIDH) signatures) contains an invalid assumption, and we provide a counterexample for this assumption---thus showing the proof of soundness is invalid. As this proof was repeated in a number of works by various authors, multiple pieces of literature are affected by this result. Due to the importance of being able to prove knowledge of an SIDH key (for example, to prevent adaptive attacks), soundness is a vital property. Surprisingly, the problem of proving knowledge of a specific isogeny turns out to be considerably more difficult than was perhaps anticipated. The main results of this paper are a sigma protocol to prove knowledge of a walk of specified length in a supersingular isogeny graph, and a second one to additionally prove that the isogeny maps some torsion points to some other torsion points (as seen in SIDH public keys). Our scheme also avoids the SIDH identification scheme soundness issue raised by Ghantous, Pintore and Veroni. In particular, our protocol provides a non-interactive way of verifying correctness of SIDH public keys, and related statements, as protection against adaptive attacks. Post-scriptum: Some months after this work was completed and made public, the SIDH assumption was broken in a series of papers by several authors. Hence, in the standard SIDH setting, some of the statements studied here now have trivial polynomial time non-interactive proofs. Nevertheless our first sigma protocol is unaffected by the attacks, and our second protocol may still be useful in present and future variants of SIDH that escape the attacks

Self-trapping and excited state absorption in fluorene homo-polymer and copolymers with benzothiadiazole and tri-phenylamine

We thank the EPSRC [EP/J009318/1 and EP/J009016/1] for funding. MJP thanks the European Research Council (ERC) for funding under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant No. 258990.Excited state absorption (ESA) is studied using time-dependent density functional theory and compared with experiments performed in dilute solutions. The molecules investigated are a fluorene pentamer, polyfluorene F8, the alternating F8 copolymer with benzothiadiazole F8BT, and two blue-emitting random copolymers F8PFB and F8TFB. Calculated and measured spectra show qualitatively comparable results. The ESA cross-section of co-polymers at its maximum is about three times lower than that of F8. The ESA spectra are found to change little upon structural relaxation of the excited state, or change in the order of sub-units in a co-polymer, for all studied molecules. In all these molecules, the strongest ESA transition is found to arise from the same electronic process, exhibiting a reversal of the charge parity. In addition, F8PFB and F8TFB are found to possess almost identical electronic behaviour.Publisher PDFPeer reviewe

An Adaptive Attack on 2-SIDH

We present a polynomial-time adaptive attack on the 2-SIDH protocol. The 2-SIDH protocol is a special instance of the countermeasure proposed by Azarderakhsh, Jao and Leonardi to perform isogeny-based key exchange with static keys in the presence of an adaptive attack. This countermeasure has also been recently explicitly proposed by Kayacan. Our attack extends the adaptive attack by Galbraith, Petit, Shani and Ti (GPST) to recover a static secret key using malformed points. The extension of GPST is non-trivial and requires learning additional information. In particular, the attack needs to recover intermediate elliptic curves in the isogeny path, and points on them. We also discuss how to extend the attack to k-SIDH when k > 2 and explain that the attack complexity is exponential in k

Adenoidectomy for otitis media with effusion (OME) in children

BACKGROUND: Otitis media with effusion (OME) is an accumulation of fluid in the middle ear cavity, common amongst young children. The fluid may cause hearing loss. When persistent, it may lead to developmental delay, social difficulty and poor quality of life. Management of OME includes watchful waiting, autoinflation, medical and surgical treatment. Adenoidectomy has often been used as a potential treatment for this condition. OBJECTIVES: To assess the benefits and harms of adenoidectomy, either alone or in combination with ventilation tubes (grommets), for OME in children. SEARCH METHODS: The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 20 January 2023. SELECTION CRITERIA: Randomised controlled trials and quasi-randomised trials in children aged 6 months to 12 years with unilateral or bilateral OME. We included studies that compared adenoidectomy (alone, or in combination with ventilation tubes) with either no treatment or non-surgical treatment. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Primary outcomes (determined following a multi-stakeholder prioritisation exercise): 1) hearing, 2) otitis media-specific quality of life, 3) haemorrhage. SECONDARY OUTCOMES: 1) persistence of OME, 2) adverse effects, 3) receptive language skills, 4) speech development, 5) cognitive development, 6) psychosocial skills, 7) listening skills, 8) generic health-related quality of life, 9) parental stress, 10) vestibular function, 11) episodes of acute otitis media. We used GRADE to assess the certainty of evidence for each outcome. Although we included all measures of hearing assessment, the proportion of children who returned to normal hearing was our preferred method to assess hearing, due to challenges in interpreting the results of mean hearing thresholds. MAIN RESULTS: We included 10 studies (1785 children). Many of the studies used concomitant interventions for all participants, including insertion of ventilation tubes or myringotomy. All included studies had at least some concerns regarding the risk of bias. We report results for our main outcome measures at the longest available follow-up. We did not identify any data on disease-specific quality of life for any of the comparisons. Further details of additional outcomes and time points are reported in the review. 1) Adenoidectomy (with or without myringotomy) versus no treatment/watchful waiting (three studies) After 12 months there was little difference in the proportion of children whose hearing had returned to normal, but the evidence was very uncertain (adenoidectomy 68%, no treatment 70%; risk ratio (RR) 0.97, 95% confidence interval (CI) 0.65 to 1.46; number needed to treat to benefit (NNTB) 50; 1 study, 42 participants). There is a risk of haemorrhage from adenoidectomy, but the absolute risk appears small (1/251 receiving adenoidectomy compared to 0/229, Peto odds ratio (OR) 6.77, 95% CI 0.13 to 342.54; 1 study, 480 participants; moderate certainty evidence). The risk of persistent OME may be slightly lower after two years in those receiving adenoidectomy (65% versus 73%), but again the difference was small (RR 0.90, 95% CI 0.81 to 1.00; NNTB 13; 3 studies, 354 participants; very low-certainty evidence). 2) Adenoidectomy (with or without myringotomy) versus non-surgical treatment No studies were identified for this comparison. 3) Adenoidectomy and bilateral ventilation tubes versus bilateral ventilation tubes (four studies) There was a slight increase in the proportion of ears with a return to normal hearing after six to nine months (57% adenoidectomy versus 42% without, RR 1.36, 95% CI 0.98 to 1.89; NNTB 7; 1 study, 127 participants (213 ears); very low-certainty evidence). Adenoidectomy may give an increased risk of haemorrhage, but the absolute risk appears small, and the evidence was uncertain (2/416 with adenoidectomy compared to 0/375 in the control group, Peto OR 6.68, 95% CI 0.42 to 107.18; 2 studies, 791 participants). The risk of persistent OME was similar for both groups (82% adenoidectomy and ventilation tubes compared to 85% ventilation tubes alone, RR 0.96, 95% CI 0.86 to 1.07; very low-certainty evidence). 4) Adenoidectomy and unilateral ventilation tube versus unilateral ventilation tube (two studies) Slightly more children returned to normal hearing after adenoidectomy, but the confidence intervals were wide (57% versus 46%, RR 1.24, 95% CI 0.79 to 1.96; NNTB 9; 1 study, 72 participants; very low-certainty evidence). Fewer children may have persistent OME after 12 months, but again the confidence intervals were wide (27.2% compared to 40.5%, RR 0.67, 95% CI 0.35 to 1.29; NNTB 8; 1 study, 74 participants). We did not identify any data on haemorrhage. 5) Adenoidectomy and ventilation tubes versus no treatment/watchful waiting (two studies) We did not identify data on the proportion of children who returned to normal hearing. However, after two years, the mean difference in hearing threshold for those allocated to adenoidectomy was -3.40 dB (95% CI -5.54 to -1.26; 1 study, 211 participants; very low-certainty evidence). There may be a small reduction in the proportion of children with persistent OME after two years, but the evidence was very uncertain (82% compared to 90%, RR 0.91, 95% CI 0.82 to 1.01; NNTB 13; 1 study, 232 participants). We noted that many children in the watchful waiting group had also received surgery by this time point. 6) Adenoidectomy and ventilation tubes versus non-surgical treatment No studies were identified for this comparison. AUTHORS' CONCLUSIONS: When assessed with the GRADE approach, the evidence for adenoidectomy in children with OME is very uncertain. Adenoidectomy may reduce the persistence of OME, although evidence about the effect of this on hearing is unclear. For patients and carers, a return to normal hearing is likely to be important, but few studies measured this outcome. We did not identify any evidence on disease-specific quality of life. There were few data on adverse effects, in particular postoperative bleeding. The risk of haemorrhage appears to be small, but should be considered when choosing a treatment strategy for children with OME. Future studies should aim to determine which children are most likely to benefit from treatment, rather than offering interventions to all children

Subpicosecond exciton dynamics in polyfluorene films from experiment and microscopic theory

The authors acknowledge financial support from the UK EPSRC (Grants EP/E065066/1, EP/E062636/1, EP/J009318/1 and EP/J009019/1), from the EPSRC Scottish Centre for Doctoral training in Condensed Matter Physics and from the European Union Seventh Framework Programme under Grant Agreement 321305.Electronic energy transfer (EET) in organic materials is a key mechanism that controls the efficiency of many processes, including light harvesting antennas in natural and artificial photosynthesis, organic solar cells, and biological systems. In this paper we have examined EET in solid-state thin-films of polyfluorene, a prototypical conjugated polymer, with ultrafast photoluminescence experiments and theoretical modeling. We observe EET occurring on a 680 ± 300 fs time scale by looking at the depolarisation of photoluminescence. An independent, predictive microscopic theoretical model is built by defining 125 000 chromophores containing both spatial and energetic disorder appropriate for a spin-coated thin film. The model predicts time-dependent exciton dynamics, without any fitting parameters, using the incoherent Förster-type hopping model. Electronic coupling between the chromophores is calculated by an improved version of the usual line-dipole model for resonant energy transfer. Without the need for higher level interactions, we find that the model is in general agreement with the experimentally observed 680 ± 300 fs depolarisation caused by EET. This leads us to conclude that femtosecond EET in polyfluorene can be described well by conventional resonant energy transfer, as long as the relevant microscopic parameters are well captured. The implications of this finding are that dipole-dipole resonant energy transfer can in some circumstances be fully adequate to describe ultrafast EET without needing to invoke strong or intermediate coupling mechanisms.PostprintPeer reviewe

Blood-based microRNAs as biomarkers for the diagnosis of colorectal cancer: a systematic review and meta-analysis

Background: Colorectal cancer (CRC) is common and associated with significant mortality. Current screening methods for CRC lack patient compliance. microRNAs (miRNAs), identified in body fluids, are negative regulators of gene expression and are dysregulated in many cancers, including CRC. This paper summarises studies identifying blood-based miRNAs dysregulated in CRC compared with healthy controls in an attempt to evaluate their use as a screening tool for the diagnosis of CRC. Methods: A search of electronic databases (PubMed and EMBASE) and grey literature was performed between January 2002 and April 2016. Studies reporting plasma or serum miRNAs in the diagnosis of CRC compared with healthy controls were selected. Patient demographics, type of patient sample (serum or plasma), method of miRNA detection, type of normalisation, and the number of significantly dysregulated miRNAs identified were recorded. Statistical evaluation of dysregulated miRNAs using sensitivity, specificity, and area under the curve (AUC) was performed. Results: Thirty-four studies investigating plasma or serum miRNAs in the diagnosis of CRC were included. A total of 31 miRNAs were found to be either upregulated (n=17) or downregulated (n=14) in CRC cases as compared with controls. Fourteen studies identified panels of ⩾2 dysregulated miRNAs. The highest AUC, 0.943, was identified using a panel of 4 miRNAs with 83.3% sensitivity and 93.1% specificity. Meta-analysis of studies identifying a single dysregulated miRNA in CRC cases compared with controls was performed. Overall sensitivity and specificity of 28 individual miRNAs in the diagnosis of CRC were 76% (95% CI 72%–80%) and 76% (95% CI 72%–80%), respectively, indicating good discriminative ability of miRNAs as biomarkers for CRC. These data did not change with sensitivity analyses. Conclusions: Blood-based miRNAs distinguish patients with CRC from healthy controls with high sensitivity and specificity comparable to other common and invasive currently used screening methods for CRC. In future, miRNAs may be used as a relatively non-invasive blood-based marker for detection of CRC