2,661 research outputs found
Independence-friendly cylindric set algebras
Independence-friendly logic is a conservative extension of first-order logic
that has the same expressive power as existential second-order logic. In her
Ph.D. thesis, Dechesne introduces a variant of independence-friendly logic
called IFG logic. We attempt to algebraize IFG logic in the same way that
Boolean algebra is the algebra of propositional logic and cylindric algebra is
the algebra of first-order logic.
We define independence-friendly cylindric set algebras and prove two main
results. First, every independence-friendly cylindric set algebra over a
structure has an underlying Kleene algebra. Moreover, the class of such
underlying Kleene algebras generates the variety of all Kleene algebras. Hence
the equational theory of the class of Kleene algebras that underly an
independence-friendly cylindric set algebra is finitely axiomatizable. Second,
every one-dimensional independence-friendly cylindric set algebra over a
structure has an underlying monadic Kleene algebra. However, the class of such
underlying monadic Kleene algebras does not generate the variety of all monadic
Kleene algebras. Finally, we offer a conjecture about which subvariety of
monadic Kleene algebras the class of such monadic Kleene algebras does
generate.Comment: 42 pages. Submitted to the Logic Journal of the IGPL. See also
http://math.colgate.edu/~amann
Perfect IFG-formulas
IFG logic is a variant of the independence-friendly logic of Hintikka and
Sandu. We answer the question: ``Which IFG-formulas are equivalent to ordinary
first-order formulas?'' We use the answer to show that the ordinary cylindric
set algebra over a structure can be embedded into a reduct of the IFG-cylindric
set algebra over the structure.Comment: 7 pages. Submitted to Logica Universalis. See also
http://math.colgate.edu/~amann
The Success of Sinister Right-Handers in Baseball
Description to be added.Cannot be left empt
The Level of Vision Necessary for Competitive Performance in Rifle Shooting: Setting the Standards for Paralympic Shooting with Vision Impairment
The aim of this study was to investigate the level of vision impairment (VI) that would reduce performance in shooting; to guide development of entry criteria to visually impaired (VI) shooting. Nineteen international-level shooters without VI took part in the study. Participants shot an air rifle, while standing, toward a regulation target placed at the end of a 10 m shooting range. Cambridge simulation glasses were used to simulate six different levels of VI. Visual acuity (VA) and contrast sensitivity (CS) were assessed along with shooting performance in each of seven conditions of simulated impairment and compared to that with habitual vision. Shooting performance was evaluated by calculating each individual’s average score in every level of simulated VI and normalizing this score by expressing it as a percentage of the baseline performance achieved with habitual vision. Receiver Operating Characteristic curves were constructed to evaluate the ability of different VA and CS cut-off criteria to appropriately classify these athletes as achieving ‘expected’ or ‘below expected’ shooting results based on their performance with different levels of VA and CS. Shooting performance remained relatively unaffected by mild decreases in VA and CS, but quickly deteriorated with more moderate losses. The ability of visual function measurements to classify shooting performance was good, with 78% of performances appropriately classified using a cut-off of 0.53 logMAR and 74% appropriately classified using a cut-off of 0.83 logCS. The current inclusion criteria for VI shooting (1.0 logMAR) is conservative, maximizing the chance of including only those with an impairment that does impact performance, but potentially excluding some who do have a genuine impairment in the sport. A lower level of impairment would include more athletes who do have a genuine impairment but would potentially include those who do not actually have an impairment that impacts performance in the sport. An impairment to CS could impact performance in the sport and might be considered in determining eligibility to take part in VI competition
(3+2) Neutrino Scheme From A Singular Double See-Saw Mechanism
We obtain a 3+2 neutrino spectrum within a left-right symmetric framework by
invoking a singular double see-saw mechanism. Higgs doublets are employed to
break and three additional fermions, singlets under the left-right
symmetric gauge group, are included. The introduction of a singularity into the
singlet fermion Majorana mass matrix results in a light neutrino sector of
three neutrinos containing predominantly , ,
separated from two neutrinos containing a small component. The
resulting active-sterile mixing in the mixing matrix is specified
once the mass eigenvalues and the submatrix corresponding to the MNS
mixing matrix are known.Comment: 5 pages, matches published versio
Diminished Antioxidant Activity of High-Density Lipoprotein–Associated Proteins in Systolic Heart Failure
Background— Diminished serum arylesterase activity, catalyzed by the high-density lipoprotein–associated paraoxonase-1, is associated with heightened systemic oxidative stress and atherosclerosis risk. In the present study, we sought to determine the prognostic role of serum arylesterase activity in subjects with systolic heart failure, particularly in relation to established cardiac biomarkers. Methods and Results— We measured serum arylesterase activity in 760 subjects with impaired left ventricular systolic function (left ventricular ejection fraction \u3c50%), and prospectively followed major adverse cardiac events (including death, nonfatal myocardial infarction, and stroke) for 3 years. In our study cohort (mean age, 64±11 years; 74% men; median left ventricular ejection fraction, 35%; median creatinine clearance, 96 mg/dL), mean serum arylesterase activity (98±25 μmol/L/min/mL) was lower compared with that in healthy control subjects (mean, 115±26 μmol/L/min/mL, P\u3c0.01) but higher compared with advanced decompensated heart failure subjects (mean, 69±22 μmol/L/min/mL, P\u3c0.01). Within our cohort, there was modest correlation between serum arylesterase activity and high-density lipoprotein cholesterol (r=0.33, P\u3c0.01) as well as B-type natriuretic peptide (r=−0.23, P\u3c0.01). Lower serum arylesterase activity was a strong predictor of poorer outcomes (hazard ratio, 2.94; 95% confidence interval, 1.54, 5.62; P\u3c0.001). After adjusting for traditional risk factors, medication use, B-type natriuretic peptide, and creatinine clearance, lower serum arylesterase still conferred an increased risk of major adverse cardiac events at 3 years (hazard ratio, 2.69; 95% confidence interval, 1.37 to 5.28; P=0.004). Conclusions— In patients with systolic heart failure, decreased serum arylesterase activity, a measure of diminished antioxidant properties of high-density lipoprotein, predicts higher risk of incident long-term adverse cardiac event independent of established clinical and biochemical risk factors
Diminished Antioxidant Activity of High-Density Lipoprotein–Associated Proteins in Systolic Heart Failure
Background— Diminished serum arylesterase activity, catalyzed by the high-density lipoprotein–associated paraoxonase-1, is associated with heightened systemic oxidative stress and atherosclerosis risk. In the present study, we sought to determine the prognostic role of serum arylesterase activity in subjects with systolic heart failure, particularly in relation to established cardiac biomarkers. Methods and Results— We measured serum arylesterase activity in 760 subjects with impaired left ventricular systolic function (left ventricular ejection fraction \u3c50%), and prospectively followed major adverse cardiac events (including death, nonfatal myocardial infarction, and stroke) for 3 years. In our study cohort (mean age, 64±11 years; 74% men; median left ventricular ejection fraction, 35%; median creatinine clearance, 96 mg/dL), mean serum arylesterase activity (98±25 μmol/L/min/mL) was lower compared with that in healthy control subjects (mean, 115±26 μmol/L/min/mL, P\u3c0.01) but higher compared with advanced decompensated heart failure subjects (mean, 69±22 μmol/L/min/mL, P\u3c0.01). Within our cohort, there was modest correlation between serum arylesterase activity and high-density lipoprotein cholesterol (r=0.33, P\u3c0.01) as well as B-type natriuretic peptide (r=−0.23, P\u3c0.01). Lower serum arylesterase activity was a strong predictor of poorer outcomes (hazard ratio, 2.94; 95% confidence interval, 1.54, 5.62; P\u3c0.001). After adjusting for traditional risk factors, medication use, B-type natriuretic peptide, and creatinine clearance, lower serum arylesterase still conferred an increased risk of major adverse cardiac events at 3 years (hazard ratio, 2.69; 95% confidence interval, 1.37 to 5.28; P=0.004). Conclusions— In patients with systolic heart failure, decreased serum arylesterase activity, a measure of diminished antioxidant properties of high-density lipoprotein, predicts higher risk of incident long-term adverse cardiac event independent of established clinical and biochemical risk factors
Difficult at dusk? Illuminating the debate on cricket ball visibility
Objectives: Investigate the visibility of new and old red, white and pink cricket balls under lighting and background conditions experienced during a day–night cricket match. Design: We modelled the luminance contrast signals available for a typical observer for a ball against backgrounds in a professional cricket ground, at different times of day. Methods: Spectral reflectance (light reflected as a function of wavelength) was derived from laboratory measurements of new and old red, white and pink balls. We also gathered spectral measurements from backgrounds (pitch, grass, sightscreens, crowd, sky) and spectral illuminance during a day–night match (natural afternoon light, through dusk to night under floodlights) from Lord's Cricket Ground (London, UK). The luminance contrast of the ball relative to the background was calculated for each combination of ball, time of day, and background surface. Results: Old red and old pink balls may offer little or no contrast against the grass, pitch and crowd. New pink balls can also be of low contrast against the crowd at dusk, as can pink and white balls (of any age) against the sky at dusk. Conclusions: Reports of difficulties with visibility of the pink ball are supported by our data. However, our modelling also shows that difficulties with visibility may also be expected under certain circumstances for red and white balls. The variable conditions in a cricket ground and the changing colour of an ageing ball make maintaining good visibility of the ball a challenge when playing day–night matches
Quantitative Analysis of the DNA Methylation Sensitivity of Transcription Factor Complexes
Although DNA modifications play an important role in gene regulation, the underlying mechanisms remain elusive. We developed EpiSELEX-seq to probe the sensitivity of transcription factor binding to DNA modification in vitro using massively parallel sequencing. Feature-based modeling quantifies the effect of cytosine methylation (5mC) on binding free energy in a position-specific manner. Application to the human bZIP proteins ATF4 and C/EBPβ and three different Pbx-Hox complexes shows that 5mCpG can both increase and decrease affinity, depending on where the modification occurs within the protein-DNA interface. The TF paralogs tested vary in their methylation sensitivity, for which we provide a structural rationale. We show that 5mCpG can also enhance in vitro p53 binding and provide evidence for increased in vivo p53 occupancy at methylated binding sites, correlating with primed enhancer histone marks. Our results establish a powerful strategy for dissecting the epigenomic modulation of protein-DNA interactions and their role in gene regulation
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