219 research outputs found

    Lawful Hacking: Using Existing Vulnerabilities for Wiretapping on the Internet

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    For years, legal wiretapping was straightforward: the officer doing the intercept connected a tape recorder or the like to a single pair of wires. By the 1990s, however, the changing structure of telecommunications—there was no longer just “Ma Bell” to talk to—and new technologies such as ISDN and cellular telephony made executing a wiretap more complicated for law enforcement. Simple technologies would no longer suffice. In response, Congress passed the Communications Assistance for Law Enforcement Act (CALEA) which mandated a standardized lawful intercept interface on all local phone switches. Since its passage, technology has continued to progress, and in the face of new forms of communication—Skype, voice chat during multiplayer online games, instant messaging, etc.—law enforcement is again experiencing problems. The FBI has called this “Going Dark”: their loss of access to suspects’ communication. According to news reports, law enforcement wants changes to the wiretap laws to require a CALEA-like interface in Internet software. CALEA, though, has its own issues: it is complex software specifically intended to create a security hole—eavesdropping capability—in the already-complex environment of a phone switch. It has unfortunately made wiretapping easier for everyone, not just law enforcement. Congress failed to heed experts’ warnings of the danger posed by this mandated vulnerability, and time has proven the experts right. The so-called “Athens Affair,” where someone used the built-in lawful intercept mechanism to listen to the cell phone calls of high Greek officials, including the Prime Minister, is but one example. In an earlier work, we showed why extending CALEA to the Internet would create very serious problems, including the security problems it has visited on the phone system. In this paper, we explore the viability and implications of an alternative method for addressing law enforcements need to access communications: legalized hacking of target devices through existing vulnerabilities in end-user software and platforms. The FBI already uses this approach on a small scale; we expect that its use will increase, especially as centralized wiretapping capabilities become less viable. Relying on vulnerabilities and hacking poses a large set of legal and policy questions, some practical and some normative. Among these are: (1) Will it create disincentives to patching? (2) Will there be a negative effect on innovation? (Lessons from the so-called “Crypto Wars” of the 1990s, and in particular the debate over export controls on cryptography, are instructive here.) (3) Will law enforcement’s participation in vulnerabilities purchasing skew the market? (4) Do local and even state law enforcement agencies have the technical sophistication to develop and use exploits? If not, how should this be handled? A larger FBI role? (5) Should law enforcement even be participating in a market where many of the sellers and other buyers are themselves criminals? (6) What happens if these tools are captured and repurposed by miscreants? (7) Should we sanction otherwise illegal network activity to aid law enforcement? (8) Is the probability of success from such an approach too low for it to be useful? As we will show, these issues are indeed challenging. We regard the issues raised by using vulnerabilities as, on balance, preferable to adding more complexity and insecurity to online systems

    Regional brain hypometabolism is unrelated to regional amyloid plaque burden

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    In its original form, the amyloid cascade hypothesis of Alzheimer's disease holds that fibrillar deposits of amyloid are an early, driving force in pathological events leading ultimately to neuronal death. Early clinicopathological investigations highlighted a number of inconsistencies leading to an updated hypothesis in which amyloid plaques give way to amyloid oligomers as the driving force in pathogenesis. Rather than focusing on the inconsistencies, amyloid imaging studies have tended to highlight the overlap between regions that show early amyloid plaque signal on positron emission tomography and that also happen to be affected early in Alzheimer's disease. Recent imaging studies investigating the regional dependency between metabolism and amyloid plaque deposition have arrived at conflicting results, with some showing regional associations and other not. We extracted multimodal neuroimaging data from the Alzheimer's disease neuroimaging database for 227 healthy controls and 434 subjects with mild cognitive impairment. We analysed regional patterns of amyloid deposition, regional glucose metabolism and regional atrophy using florbetapir ((18)F) positron emission tomography, (18)F-fluordeoxyglucose positron emission tomography and T1-weighted magnetic resonance imaging, respectively. Specifically, we derived grey matter density and standardized uptake value ratios for both positron emission tomography tracers in 404 functionally defined regions of interest. We examined the relation between regional glucose metabolism and amyloid plaques using linear models. For each region of interest, correcting for regional grey matter density, age, education and disease status, we tested the association of regional glucose metabolism with (i) cortex-wide florbetapir uptake; (ii) regional (i.e. in the same region of interest) florbetapir uptake; and (iii) regional florbetapir uptake while correcting in addition for cortex-wide florbetapir uptake. P-values for each setting were Bonferroni corrected for 404 tests. Regions showing significant hypometabolism with increasing cortex-wide amyloid burden were classic Alzheimer's disease-related regions: the medial and lateral parietal cortices. The associations between regional amyloid burden and regional metabolism were more heterogeneous: there were significant hypometabolic effects in posterior cingulate, precuneus, and parietal regions but also significant positive associations in bilateral hippocampus and entorhinal cortex. However, after correcting for global amyloid burden, few of the negative associations remained and the number of positive associations increased. Given the wide-spread distribution of amyloid plaques, if the canonical cascade hypothesis were true, we would expect wide-spread, cortical hypometabolism. Instead, cortical hypometabolism appears to be linked to global amyloid burden. Thus we conclude that regional fibrillar amyloid deposition has little to no association with regional hypometabolism

    Seeking the Source: Criminal Defendants' Constitutional Right to Source Code

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    Who Underreports Smoking on Birth Records: A Monte Carlo Predictive Model with Validation

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    Research has shown that self-reports of smoking during pregnancy may underestimate true prevalence. However, little is known about which populations have higher rates of underreporting. Availability of more accurate measures of smoking during pregnancy could greatly enhance the usefulness of existing studies on the effects of maternal smoking offspring, especially in those populations where underreporting may lead to underestimation of the impact of smoking during pregnancy.In this paper, we develop a statistical Monte Carlo model to estimate patterns of underreporting of smoking during pregnancy, and apply it to analyze the smoking self-report data from birth certificates in the state of Massachusetts. Our results illustrate non-uniform patterns of underreporting of smoking during pregnancy among different populations. Estimates of likely underreporting of smoking during pregnancy were highest among mothers who were college-educated, married, aged 30 years or older, employed full-time, and planning to breastfeed. The model's findings are validated and compared to an existing underreporting adjustment approach in the Maternal and Infant Smoking Study of East Boston (MISSEB).The validation results show that when biological assays are not available, the Monte Carlo method proposed can provide a more accurate estimate of the smoking status during pregnancy than self-reports alone. Such methods hold promise for providing a better assessment of the impact of smoking during pregnancy

    Numerical Portrait of a Relativistic Thin Film BCS Superfluid

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    We present results of numerical simulations of the 2+1d Nambu - Jona-Lasinio model with a non-zero baryon chemical potential mu including the effects of a diquark source term. Diquark condensates, susceptibilities and masses are measured as functions of source strength j. The results suggest that diquark condensation does not take place in the high density phase mu>mu_c, but rather that the condensate scales non-analytically with j implying a line of critical points and long range phase coherence. Analogies are drawn with the low temperature phase of the 2d XY model. The spectrum of the spin-1/2 sector is also studied yielding the quasiparticle dispersion relation. There is no evidence for a non-zero gap; rather the results are characteristic of a normal Fermi liquid with Fermi velocity less than that of light. We conclude that the high density phase of the model describes a relativistic gapless thin film BCS superfluid.Comment: 37 pages, 16 figure

    Effects of traumatic brain injury and posttraumatic stress disorder on development of Alzheimer's disease in Vietnam Veterans using the Alzheimer's Disease Neuroimaging Initiative: Preliminary report

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    Introduction Traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD) have previously been reported to be associated with increased risk of Alzheimer's disease (AD). We are using biomarkers to study Vietnam Veterans with/without mild cognitive impairment with a history of at least one TBI and/or ongoing PTSD to determine whether these contribute to the development of AD. Methods Potential subjects identified by Veterans Administration records underwent an initial telephone screen. Consented subjects underwent clinical evaluation, lumbar puncture, structural magnetic resonance imaging, and amyloid positron emission tomography (PET) scans. Results We observed worse cognitive functioning in PTSD and TBI + PTSD groups, worse global cognitive functioning in the PTSD group, lower superior parietal volume in the TBI + PTSD group, and lower amyloid positivity in the PTSD group, but not the TBI group compared to controls without TBI/PTSD. Medial temporal lobe atrophy was not increased in the PTSD and/or TBI groups. Discussion Preliminary results do not indicate that TBI or PTSD increase the risk for AD measured by amyloid PET. Additional recruitment, longitudinal follow-up, and tau-PET scans will provide more information in the future

    Mutations in the UBIAD1 Gene, Encoding a Potential Prenyltransferase, Are Causal for Schnyder Crystalline Corneal Dystrophy

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    Schnyder crystalline corneal dystrophy (SCCD, MIM 121800) is a rare autosomal dominant disease characterized by progressive opacification of the cornea resulting from the local accumulation of lipids, and associated in some cases with systemic dyslipidemia. Although previous studies of the genetics of SCCD have localized the defective gene to a 1.58 Mbp interval on chromosome 1p, exhaustive sequencing of positional candidate genes has thus far failed to reveal causal mutations. We have ascertained a large multigenerational family in Nova Scotia affected with SCCD in which we have confirmed linkage to the same general area of chromosome 1. Intensive fine mapping in our family revealed a 1.3 Mbp candidate interval overlapping that previously reported. Sequencing of genes in our interval led to the identification of five putative causal mutations in gene UBIAD1, in our family as well as in four other small families of various geographic origins. UBIAD1 encodes a potential prenyltransferase, and is reported to interact physically with apolipoprotein E. UBIAD1 may play a direct role in intracellular cholesterol biochemistry, or may prenylate other proteins regulating cholesterol transport and storage

    Head injury is associated with tau deposition on PET in MCI and AD patients

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    Introduction: Head injuries (HI) are a risk factor for dementia, but the underlying etiology is not fully known. Understanding whether tau might mediate this relationship is important. Methods: Cognition and tau deposition were compared between 752 individuals with (impaired, n = 302) or without cognitive impairment (CN, n = 450) with amyloid and [18F]flortaucipir positron emission tomography, HI history information, and cognitive testing from the Alzheimer's Disease Neuroimaging Initiative and the Indiana Memory and Aging Study. Results: Sixty-three (38 CN, 25 impaired) reported a history of HI. Higher neuropsychiatric scores and poorer memory were observed in those with a history of HI. Tau was higher in individuals with a history of HI, especially those who experienced a loss of consciousness (LOC). Results were driven by impaired individuals, especially amyloid beta-positive individuals with history of HI with LOC. Discussion: These findings suggest biological changes, such as greater tau, are associated with HI in individuals with cognitive impairment. Small effect sizes were observed; thus, further studies should replicate and extend these results

    Prevalence of amyloid PET positivity in dementia syndromes: a meta-analysis

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    IMPORTANCE: Amyloid-β positron emission tomography (PET) imaging allows in vivo detection of fibrillar plaques, a core neuropathological feature of Alzheimer disease (AD). Its diagnostic utility is still unclear because amyloid plaques also occur in patients with non-AD dementia. OBJECTIVE: To use individual participant data meta-analysis to estimate the prevalence of amyloid positivity on PET in a wide variety of dementia syndromes. DATA SOURCES: The MEDLINE and Web of Science databases were searched from January 2004 to April 2015 for amyloid PET studies. STUDY SELECTION: Case reports and studies on neurological or psychiatric diseases other than dementia were excluded. Corresponding authors of eligible cohorts were invited to provide individual participant data. DATA EXTRACTION AND SYNTHESIS: Data were provided for 1359 participants with clinically diagnosed AD and 538 participants with non-AD dementia. The reference groups were 1849 healthy control participants (based on amyloid PET) and an independent sample of 1369 AD participants (based on autopsy). MAIN OUTCOMES AND MEASURES: Estimated prevalence of positive amyloid PET scans according to diagnosis, age, and apolipoprotein E (APOE) ε4 status, using the generalized estimating equations method. RESULTS: The likelihood of amyloid positivity was associated with age and APOE ε4 status. In AD dementia, the prevalence of amyloid positivity decreased from age 50 to 90 years in APOE ε4 noncarriers (86% [95% CI, 73%-94%] at 50 years to 68% [95% CI, 57%-77%] at 90 years; n = 377) and to a lesser degree in APOE ε4 carriers (97% [95% CI, 92%-99%] at 50 years to 90% [95% CI, 83%-94%] at 90 years; n = 593; P < .01). Similar associations of age and APOE ε4 with amyloid positivity were observed in participants with AD dementia at autopsy. In most non-AD dementias, amyloid positivity increased with both age (from 60 to 80 years) and APOE ε4 carriership (dementia with Lewy bodies: carriers [n = 16], 63% [95% CI, 48%-80%] at 60 years to 83% [95% CI, 67%-92%] at 80 years; noncarriers [n = 18], 29% [95% CI, 15%-50%] at 60 years to 54% [95% CI, 30%-77%] at 80 years; frontotemporal dementia: carriers [n = 48], 19% [95% CI, 12%-28%] at 60 years to 43% [95% CI, 35%-50%] at 80 years; noncarriers [n = 160], 5% [95% CI, 3%-8%] at 60 years to 14% [95% CI, 11%-18%] at 80 years; vascular dementia: carriers [n = 30], 25% [95% CI, 9%-52%] at 60 years to 64% [95% CI, 49%-77%] at 80 years; noncarriers [n = 77], 7% [95% CI, 3%-18%] at 60 years to 29% [95% CI, 17%-43%] at 80 years. CONCLUSIONS AND RELEVANCE: Among participants with dementia, the prevalence of amyloid positivity was associated with clinical diagnosis, age, and APOE genotype. These findings indicate the potential clinical utility of amyloid imaging for differential diagnosis in early-onset dementia and to support the clinical diagnosis of participants with AD dementia and noncarrier APOE ε4 status who are older than 70 years
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