546 research outputs found

    Local and distributed PiB accumulation associated with development of preclinical Alzheimer\u27s disease

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    Amyloid-beta plaques are a hallmark of Alzheimer\u27s disease (AD) that can be assessed by amyloid imaging (e.g., Pittsburgh B compound [PiB]) and summarized as a scalar value. Summary values may have clinical utility but are an average over many regions of interest, potentially obscuring important topography. This study investigates the longitudinal evolution of amyloid topographies in cognitively normal older adults who had normal (N = 131) or abnormal (N = 26) PiB scans at baseline. At 3 years follow-up, 16 participants with a previously normal PiB scan had conversion to PiB scans consistent with preclinical AD. We investigated the multivariate relationship (canonical correlation) between baseline and follow-up PiB topographies. Furthermore, we used penalized regression to investigate the added information derived from PiB topography compared to summary measures. PiB accumulation can be local, that is, a topography predicting the same topography in the future, and/or distributed, that is, one topography predicting another. Both local and distributed PiB accumulation was associated with conversion of PiB status. Additionally, elements of the multivariate topography, and not the commonly used summary scalar, correlated with future PiB changes. Consideration of the entire multivariate PiB topography provides additional information regarding the development of amyloid-beta pathology in very early preclinical AD

    The usefulness of case reports in managing emerging infectious disease

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    Emerging infectious diseases are an important problem in medicine. Case reports usually document episodes in the early emerging phase or in a small outbreak. Although the case report is considered weak evidence in medical literature, it is usually the first report when there is a new emerging infectious disease. There is no doubt that case reports can provide useful information for further case series, reviews and studies. This editorial focuses on the usefulness of the case report on emerging infectious disease to the medical society. Publication in this area is highly welcomed by the journal and can serve as a future point of reference

    Analysis and Improvement of the Random Delay Countermeasure of CHES 2009

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    Random delays are often inserted in embedded software to protect against side-channel and fault attacks. At CHES 2009 a new method for generation of random delays was described that increases the attacker's uncertainty about the position of sensitive operations. In this paper we show that the CHES 2009 method is less secure than claimed. We describe an improved method for random delay generation which does not suffer from the same security weakness. We also show that the paper's criterion to measure the security of random delays can be misleading, so we introduce a new criterion for random delays which is directly connected to the number of acquisitions required to break an implementation. We mount a power analysis attack against an 8-bit implementation of the improved method verifying its higher security in practice

    Finding home: Black queer historical scholarship in the United States Part II

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    This essay surveys the extant historical and historically minded scholarship about the political, social, and cultural life of African American/black LGBT/queer. Characterizing this area of inquiry as “black queer historical studies,” this essay addresses scholars’ diverse approaches to the challenge of archival research, current scholarship about the intersecting histories of blackness and queerness in the United States, and four key topical concerns: black “lesbian” histories, gender transgression, class, and community formation/politics.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149251/1/hic312533.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149251/2/hic312533_am.pd

    Chronic pancreatitis in dogs : a retrospective study of clinical, clinicopathological, and histopathological findings in 61 cases

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    The objective of the present study was to characterize the clinical, clinicopathologic, and histopathologic findings of dogs with chronic pancreatitis. The necropsy database at Texas A&M University was searched for reports of dogs with histologic evidence of chronic pancreatitis defined as irreversible histologic changes of the pancreas, i.e. fibrosis and atrophy. Medical records and necropsy reports were retrieved and reviewed. A reference necropsy population of 100 randomly selected dogs was used for signalment and concurrent disease comparisons. Cases were categorized as clinical or incidental chronic pancreatitis based on the presence of vomiting, decreased appetite, or both versus neither of these signs. All archived pancreata samples were evaluated histologically and scored using a published pancreatic scoring system. A total of 61 dogs with chronic pancreatitis were included in the study. The most frequent clinical signs were lethargy, decreased appetite, vomiting, and diarrhea. Compared to the reference necropsy population, chronic pancreatitis cases were more likely to be older, neutered, and of the non-sporting/toy breed group and to have concurrent endocrine, hepatobiliary, or neurologic diseases. Clinical chronic pancreatitis cases had significantly higher histological scores for pancreatic necrosis and peripancreatic fat necrosis. Clinical chronic pancreatitis cases were significantly more likely to have hepatobiliary or endocrine disease as well as increased liver enzyme activities, and cholesterol and bilirubin concentrations. In conclusion, clinical disease resulting from chronic pancreatitis might be related to the presence of pancreatic necrosis and pancreatic fat necrosis. The signalment, presentation, and concurrent diseases of dogs with chronic pancreatitis are similar to those previously reported for dogs with acute pancreatitis.http://www.elsevier.com/locate/tvjlam2013ab201

    Chronic pancreatitis in dogs: A retrospective study of clinical, clinicopathological, and histopathological findings in 61 cases

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    The objective of the present study was to characterize the clinical, clinicopathologic, and histopathologic findings of dogs with chronic pancreatitis. The necropsy database at Texas A&M University was searched for reports of dogs with histologic evidence of chronic pancreatitis defined as irreversible histologic changes of the pancreas, i.e. fibrosis and atrophy. Medical records and necropsy reports were retrieved and reviewed. A reference necropsy population of 100 randomly selected dogs was used for signalment and concurrent disease comparisons. Cases were categorized as clinical or incidental chronic pancreatitis based on the presence of vomiting, decreased appetite, or both versus neither of these signs. All archived pancreata samples were evaluated histologically and scored using a published pancreatic scoring system. A total of 61 dogs with chronic pancreatitis were included in the study. The most frequent clinical signs were lethargy, decreased appetite, vomiting, and diarrhea. Compared to the reference necropsy population, chronic pancreatitis cases were more likely to be older, neutered, and of the non-sporting/toy breed group and to have concurrent endocrine, hepatobiliary, or neurologic diseases. Clinical chronic pancreatitis cases had significantly higher histological scores for pancreatic necrosis and peripancreatic fat necrosis. Clinical chronic pancreatitis cases were significantly more likely to have hepatobiliary or endocrine disease as well as increased liver enzyme activities, and cholesterol and bilirubin concentrations. In conclusion, clinical disease resulting from chronic pancreatitis might be related to the presence of pancreatic necrosis and pancreatic fat necrosis. The signalment, presentation, and concurrent diseases of dogs with chronic pancreatitis are similar to those previously reported for dogs with acute pancreatitis.http://www.elsevier.com/locate/tvjlam2013ab201

    On the automatic construction of indistinguishable operations

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    An increasingly important design constraint for software running on ubiquitous computing devices is security, particularly against physical methods such as side-channel attack. One well studied methodology for defending against such attacks is the concept of indistinguishable functions which leak no information about program control flow since all execution paths are computationally identical. However, constructing such functions by hand becomes laborious and error prone as their complexity increases. We investigate techniques for automating this process and find that effective solutions can be constructed with only minor amounts of computational effort.Fundação para a Ciência e Tecnologia - SFRH/BPD/20528/2004

    Observation of BϕKB\to \phi K and BϕKB\to \phi K^{*}

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    We have studied two-body charmless hadronic decays of BB mesons into the final states phi K and phi K^*. Using 9.7 million BBˉB\bar{B} pairs collected with the CLEO II detector, we observe the decays B- -> phi K- and B0 -> phi K*0 with the following branching fractions: BR(B- -> phi K-)=(5.5 +2.1-1.8 +- 0.6) x 10^{-6} and BR(B0 -> phi K*0)=(11.5 +4.5-3.7 +1.8-1.7) x 10^{-6}. We also see evidence for the decays B0 -> phi K0 and B- -> phi K*-. However, since the statistical significance is not overwhelming for these modes we determine upper limits of <12.3 x 10^{-6} and <22.5 x 10^{-6} (90% C.L.) respectively.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN
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