90 research outputs found
Decidability Results for the Boundedness Problem
We prove decidability of the boundedness problem for monadic least
fixed-point recursion based on positive monadic second-order (MSO) formulae
over trees. Given an MSO-formula phi(X,x) that is positive in X, it is
decidable whether the fixed-point recursion based on phi is spurious over the
class of all trees in the sense that there is some uniform finite bound for the
number of iterations phi takes to reach its least fixed point, uniformly across
all trees. We also identify the exact complexity of this problem. The proof
uses automata-theoretic techniques. This key result extends, by means of
model-theoretic interpretations, to show decidability of the boundedness
problem for MSO and guarded second-order logic (GSO) over the classes of
structures of fixed finite tree-width. Further model-theoretic transfer
arguments allow us to derive major known decidability results for boundedness
for fragments of first-order logic as well as new ones
Tree-width for first order formulae
We introduce tree-width for first order formulae \phi, fotw(\phi). We show
that computing fotw is fixed-parameter tractable with parameter fotw. Moreover,
we show that on classes of formulae of bounded fotw, model checking is fixed
parameter tractable, with parameter the length of the formula. This is done by
translating a formula \phi\ with fotw(\phi)<k into a formula of the k-variable
fragment L^k of first order logic. For fixed k, the question whether a given
first order formula is equivalent to an L^k formula is undecidable. In
contrast, the classes of first order formulae with bounded fotw are fragments
of first order logic for which the equivalence is decidable.
Our notion of tree-width generalises tree-width of conjunctive queries to
arbitrary formulae of first order logic by taking into account the quantifier
interaction in a formula. Moreover, it is more powerful than the notion of
elimination-width of quantified constraint formulae, defined by Chen and Dalmau
(CSL 2005): for quantified constraint formulae, both bounded elimination-width
and bounded fotw allow for model checking in polynomial time. We prove that
fotw of a quantified constraint formula \phi\ is bounded by the
elimination-width of \phi, and we exhibit a class of quantified constraint
formulae with bounded fotw, that has unbounded elimination-width. A similar
comparison holds for strict tree-width of non-recursive stratified datalog as
defined by Flum, Frick, and Grohe (JACM 49, 2002).
Finally, we show that fotw has a characterization in terms of a cops and
robbers game without monotonicity cost
Validierung und ReliabilitĂ€tsprĂŒfung des Nijmegen Cochlear Implant Questionnaire in deutscher Sprache
Hintergrund: Der Nijmegen Cochlear Implant Questionnaire (NCIQ) ist ein krankheitsspezifischer Fragebogen zur Erhebung der gesundheitsbezogenen LebensqualitĂ€t von Patienten vor und nach Cochleaimplantation. Ziel der Arbeit: Validierung und ReliabilitĂ€tsprĂŒfung der deutschen Ăbersetzung des NCIQ. Material und Methoden: Es wurde eine prospektive Studie an 100 postlingual ertaubten oder hochgradig schwerhörigen Patienten durchgefĂŒhrt, welche prĂ€operativ sowie 3 und 6 Monate nach einer Cochleaimplantation mittels NCIQ, Abbreviated Profile of Hearing Aid Benefit (APHAB) und Hearing Participation Scale (HPS) untersucht wurden. Als Kontrolle fungierte ein postlingual ertaubtes oder hochgradig schwerhöriges, unbehandeltes Patientenkollektiv (nâŻ=â54). Cronbachâα und Test-Retest-ReliabilitĂ€t dienten der ReliabilitĂ€tsĂŒberprĂŒfung. Es wurde auf Inhaltsâ, Ăbereinstimmungs- und auf diskriminative ValiditĂ€t getestet. Die KonstruktvaliditĂ€tsprĂŒfung basiert auf kĂŒrzlich veröffentlichen Daten. Als GĂŒtekriterien wurden die SensitivitĂ€t und eine ROC("Receiver Operating Characteristic")-Analyse, inklusive AUC("Area Under the ROC Curve")-Betrachtung, eingesetzt. Ergebnisse: Das Test-Retesting ergab nach 3 und 6 Monaten postoperativ stabile NCIQ-Werte. Die Cronbach-α-Werte wiesen auf eine gute interne Konsistenz hin. Der NCIQ diskriminierte valide zwischen behandelten und unbehandelten Patientengruppen. Es ergaben sich statistisch signifikante, wenn auch schwache, Korrelationen zwischen dem NCIQ und dem APHAB (râŻ=â-0,22; pâŻ=â0,04) und dem HPS (râŻ=â0,30; pâŻ=â0,01). SensitivitĂ€ts- und ROC-Analysen zeigten eine gute MessqualitĂ€t des deutschsprachigen NCIQ. Schlussfolgerung: Die deutsche Ăbersetzung des NCIQ misst zuverlĂ€ssig und valide die LebensqualitĂ€t vor und nach Cochleaimplantation und kann zur klinischen Erfolgskontrolle nach Cochleaimplantationen verwendet werden.Background: The Nijmegen Cochlear Implant Questionnaire (NCIQ) is a disease-speciïŹc
questionnaire to determine the health-related quality of life (HRQoL) of patients before
and after cochlear implantation. Objective: This study aimed to assess the validity and reliability of the German translation of the NCIQ. Materials and methods: A prospective study was performed in 100 postlingually deaf or severely hearing-impaired patients. HRQoL was assessed using the NCIQ, the Abbreviated ProïŹle of Hearing Aid BeneïŹt (APHAB), and the Hearing Participation Scale (HPS) before as well as 3 and 6 months after cochlear implantation. An untreated group of postlingually deaf or severely hearing-impaired patients (n = 54) served as a control. Cronbach's α and testâretest reliability were measured. The content, discrimination, and agreement validity were tested. The evaluation of construct validity was based on recently published data. Sensitivity and receiver operating curve (ROC) analysis,
including consideration of the area under the curve (AUC), were used as quality criteria. Results: The test-retest analysis showed stable NCIQ values 3 and 6 months postoperatively. The Cronbachâs α values indicated good internal consistency. The NCIQ validly discriminated between treated and untreated patient groups. There were statistically signiïŹcant albeit weak correlations between the NCIQ and the APHAB (r = -0.22; p = 0.04) and the HPS (r = 0.30; p = 0.01). Sensitivity and ROC analyses showed good measurement quality of the German-speaking NCIQ. Conclusion: The German translation of the NCIQ reliably and validly measures HRQoL before and after cochlear implantation and can be used for clinical monitoring after treatment with cochlear implants
Distinct Patterns of IFITM-Mediated Restriction of Filoviruses, SARS Coronavirus, and Influenza A Virus
Interferon-inducible transmembrane proteins 1, 2, and 3 (IFITM1, 2, and 3) are recently identified viral restriction factors that inhibit infection mediated by the influenza A virus (IAV) hemagglutinin (HA) protein. Here we show that IFITM proteins restricted infection mediated by the entry glycoproteins (GP1,2) of Marburg and Ebola filoviruses (MARV, EBOV). Consistent with these observations, interferon-ÎČ specifically restricted filovirus and IAV entry processes. IFITM proteins also inhibited replication of infectious MARV and EBOV. We observed distinct patterns of IFITM-mediated restriction: compared with IAV, the entry processes of MARV and EBOV were less restricted by IFITM3, but more restricted by IFITM1. Moreover, murine Ifitm5 and 6 did not restrict IAV, but efficiently inhibited filovirus entry. We further demonstrate that replication of infectious SARS coronavirus (SARS-CoV) and entry mediated by the SARS-CoV spike (S) protein are restricted by IFITM proteins. The profile of IFITM-mediated restriction of SARS-CoV was more similar to that of filoviruses than to IAV. Trypsin treatment of receptor-associated SARS-CoV pseudovirions, which bypasses their dependence on lysosomal cathepsin L, also bypassed IFITM-mediated restriction. However, IFITM proteins did not reduce cellular cathepsin activity or limit access of virions to acidic intracellular compartments. Our data indicate that IFITM-mediated restriction is localized to a late stage in the endocytic pathway. They further show that IFITM proteins differentially restrict the entry of a broad range of enveloped viruses, and modulate cellular tropism independently of viral receptor expression
Maternal dietary intake of nitrates, nitrites and nitrosamines and selected birth defects in offspring: a case-control study
BACKGROUND: Dietary intake of nitrates, nitrites, and nitrosamines can increase the endogenous formation of N-nitroso compounds in the stomach. Results from animal studies suggest that these compounds might be teratogenic. We examined the relationship between maternal dietary intake of nitrates, nitrites (including plant and animal sources as separate groups), and nitrosamines and several types of birth defects in offspring. METHODS: For this population-based caseâcontrol study, data from a 58-question food frequency questionnaire, adapted from the short Willett Food Frequency Questionnaire and administered as part of the National Birth Defects Prevention Study (NBDPS), were used to estimate daily intake of dietary nitrates, nitrites, and nitrosamines in a sample of 6544 mothers of infants with neural tube defects (NTD)s, oral clefts (OC)s, or limb deficiencies (LD)s and 6807 mothers of unaffected control infants. Total daily intake of these compounds was divided into quartiles based on the control mother distributions. Odds ratios (OR)s and 95% confidence intervals (CI)s were estimated using logistic regression; estimates were adjusted for maternal daily caloric intake, maternal race-ethnicity, education, dietary folate intake, high fat diet (> 30% of calories from fat), and state of residence. RESULTS: While some unadjusted ORs for NTDS had 95% (CI)s that excluded the null value, none remained significant after adjustment for covariates, and the effect sizes were small (adjusted odds ratios [aOR] <1.12). Similar results were found for OCs and LDs with the exception of animal nitrites and cleft lip with/without cleft palate (aORs and CIs for quartile 4 compared to quartile 1 =1.24; CI=1.05-1.48), animal nitrites and cleft lip (4th quartile aOR=1.32; CI=1.01-1.72), and total nitrite and intercalary LD (4th quartile aOR=4.70; CI=1.23-17.93). CONCLUSIONS: Overall, odds of NTDs, OCs or LDs did not appear to be significantly associated with estimated dietary intake of nitrate, nitrite, and nitrosamines
Wolves in the Wolds: Late Capitalism, the English Eerie, and the Wyrd Case of âOld Stinkerâ the Hull Werewolf
In this article, I depart from the earlier opinions of Emily Gerard, Sabine Baring-Gould, and others, who explained the disappearance of the werewolf in folklore as following the extinction of the wolf. I argue instead that British literature is distinctive in representing a history of werewolf sightings in places in Britain where there were once wolves. I draw on the idea of absence, manifestations of the English eerie, and the turbulence of England in the era of late capitalism to illuminate my analysis of the representation of contemporary werewolf sightingsPeer reviewe
Emergency department documentation templates: variability in template selection and association with physical examination and test ordering in dizziness presentations
Abstract
Background
Clinical documentation systems, such as templates, have been associated with process utilization. The T-System emergency department (ED) templates are widely used but lacking are analyses of the templates association with processes. This system is also unique because of the many different template options available, and thus the selection of the template may also be important. We aimed to describe the selection of templates in ED dizziness presentations and to investigate the association between items on templates and process utilization.
Methods
Dizziness visits were captured from a population-based study of EDs that use documentation templates. Two relevant process outcomes were assessed: head computerized tomography (CT) scan and nystagmus examination. Multivariable logistic regression was used to estimate the probability of each outcome for patients who did or did not receive a relevant-item template. Propensity scores were also used to adjust for selection effects.
Results
The final cohort was 1,485 visits. Thirty-one different templates were used. Use of a template with a head CT item was associated with an increase in the adjusted probability of head CT utilization from 12.2% (95% CI, 8.9%-16.6%) to 29.3% (95% CI, 26.0%-32.9%). The adjusted probability of documentation of a nystagmus assessment increased from 12.0% (95%CI, 8.8%-16.2%) when a nystagmus-item template was not used to 95.0% (95% CI, 92.8%-96.6%) when a nystagmus-item template was used. The associations remained significant after propensity score adjustments.
Conclusions
Providers use many different templates in dizziness presentations. Important differences exist in the various templates and the template that is used likely impacts process utilization, even though selection may be arbitrary. The optimal design and selection of templates may offer a feasible and effective opportunity to improve care delivery.http://deepblue.lib.umich.edu/bitstream/2027.42/112490/1/12913_2010_Article_1586.pd
Impacts of 1.5°C Global Warming on Natural and Human Systems
An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate povert
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