Relative Abundance, Seasonal Distribution and Taxonomy of Sphingidae of Northeast Arkansas

A total of 38 species of sphingids, with keys and descriptions, are reported from Northeast Arkansas. Graphs and tables are presented to show relative abundance and seasonal distribution. Drawings of genitalia, fore tibiae, and forewings, as well as photographs of species in the key are included

From one solution of a 3-satisfiability formula to a solution cluster: Frozen variables and entropy

A solution to a 3-satisfiability (3-SAT) formula can be expanded into a cluster, all other solutions of which are reachable from this one through a sequence of single-spin flips. Some variables in the solution cluster are frozen to the same spin values by one of two different mechanisms: frozen-core formation and long-range frustrations. While frozen cores are identified by a local whitening algorithm, long-range frustrations are very difficult to trace, and they make an entropic belief-propagation (BP) algorithm fail to converge. For BP to reach a fixed point the spin values of a tiny fraction of variables (chosen according to the whitening algorithm) are externally fixed during the iteration. From the calculated entropy values, we infer that, for a large random 3-SAT formula with constraint density close to the satisfiability threshold, the solutions obtained by the survey-propagation or the walksat algorithm belong neither to the most dominating clusters of the formula nor to the most abundant clusters. This work indicates that a single solution cluster of a random 3-SAT formula may have further community structures.Comment: 13 pages, 6 figures. Final version as published in PR

A Random Matrix Model of Adiabatic Quantum Computing

We present an analysis of the quantum adiabatic algorithm for solving hard instances of 3-SAT (an NP-complete problem) in terms of Random Matrix Theory (RMT). We determine the global regularity of the spectral fluctuations of the instantaneous Hamiltonians encountered during the interpolation between the starting Hamiltonians and the ones whose ground states encode the solutions to the computational problems of interest. At each interpolation point, we quantify the degree of regularity of the average spectral distribution via its Brody parameter, a measure that distinguishes regular (i.e., Poissonian) from chaotic (i.e., Wigner-type) distributions of normalized nearest-neighbor spacings. We find that for hard problem instances, i.e., those having a critical ratio of clauses to variables, the spectral fluctuations typically become irregular across a contiguous region of the interpolation parameter, while the spectrum is regular for easy instances. Within the hard region, RMT may be applied to obtain a mathematical model of the probability of avoided level crossings and concomitant failure rate of the adiabatic algorithm due to non-adiabatic Landau-Zener type transitions. Our model predicts that if the interpolation is performed at a uniform rate, the average failure rate of the quantum adiabatic algorithm, when averaged over hard problem instances, scales exponentially with increasing problem size.Comment: 9 pages, 7 figure

Dietary restriction in ILSXISS mice is associated with widespread changes in splicing regulatory factor expression levels.

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record Dietary restriction (DR) represents one of the most reproducible interventions to extend lifespan and improve health outcomes in a wide range of species, but substantial variability in DR response has been observed, both between and within species. The mechanisms underlying this variation in effect are still not well characterised. Splicing regulatory factors have been implicated in the pathways linked with DR-induced longevity in C. elegans and are associated with lifespan itself in mice and humans. We used qRT-PCR to measure the expression levels of a panel of 20 age- and lifespan-associated splicing regulatory factors in brain, heart and kidney derived from three recombinant inbred strains of mice with variable lifespan responses to short-term (2 months) or long-term (10 months) 40% DR to determine their relationship to DR-induced longevity. We identified 3 patterns of association; i) splicing factors associated with DR alone, ii) splicing factors associated with strain alone or iii) splicing factors associated with both DR and strain. Tissue specific variation was noted in response to short term or long-term DR, with the majority of effects noted in brain following long term DR in the positive responder strain TejJ89. Association in heart and kidney were less evident, and occurred following short term DR. Splicing factors associated with both DR and strain may be mechanistically involved in strain-specific differences in response to DR. We provide here evidence concordant with a role for some splicing factors in the lifespan modulatory effects of DR across different mouse strains and in different tissues

An Optical and X-ray Examination of Two Radio Supernova Remnant Candidates in 30 Doradus

The giant HII region 30 Doradus is known for its violent internal motions and bright diffuse X-ray emission, suggesting the existence of supernova remnants (SNRs), but no nonthermal radio emission has been detected. Recently, Lazendic et al. compared the H-alpha/H-beta and radio/H-alpha ratios and suggested two small radio sources to be nonthermal and thus SNR candidates; however, no optical or X-ray counterparts were detected. We have used high-resolution optical images and high-dispersion spectra to examine the morphological, spectral, and kinematic properties of these two SNR candidates, and still find no optical evidence supporting their identification as SNRs. We have also determined the X-ray luminosities of these SNR candidates, and find them 1-3 orders of magnitude lower than those commonly seen in young SNRs. High extinction can obscure optical and X-ray signatures of an SNR, but would prohibit the use of a high radio/H-alpha ratio to identify nonthermal radio emission. We suggest that the SNR candidate MCRX J053831.8-690620 is associated with a young star forming region; while the radio emission originates from the obscured star forming region, the observed optical emission is dominated by the foreground. We suggest that the SNR candidate MCRX J053838.8-690730 is associated with a dust/molecular cloud, which obscures some optical emission but not the radio emission.Comment: 13 pages, 2 figures, accepted for publication in the ApJ, Nov 10, 200

Hubble Space Telescope Photometry of Hodge 301: An "Old" Star Cluster in 30 Doradus

We present Hubble Space Telescope Planetary Camera UVI data for the little-studied cluster Hodge 301 3' northwest of 30 Doradus' central ionizing cluster R136. The average reddening of Hodge 301 is found to be = (0.28+-0.05) mag from published infrared and ultraviolet photometry. Using two different sets of evolutionary models, we derive an age of ~ 20-25 Myr for Hodge 301, which makes it roughly 10 times as old as R136. Hodge 301 is the most prominent representative of the oldest population in the 30 Dor starburst region; a region that has undergone multiple star formation events. This range of ages is an important consideration for the modelling of starburst regions. Hodge 301 shows a widened upper main sequence largely caused by Be stars. We present a list of Be star candidates. The slope of the initial mass function for intermediate-mass main sequence stars ranging from 10 to 1.3 solar masses is found to be -1.4+-0.1 in good agreement with a Salpeter law. There is no indication for a truncation or change of slope of the IMF within this mass range. In accordance with the age of Hodge 301 no obvious pre-main-sequence stars are seen down to 1 solar mass. We estimate that up to 41+-7 stars with more than 12 solar masses may have turned into supernovae since the formation of the cluster. Multiple supernova explosions are the most likely origin of the extremely violent gas motions and the diffuse X-ray emission observed in the cluster surroundings.Comment: To appear in the Astronomical Journal (Feb 2000 issue). 16 pages in two-column style. 9 separate figures, in part in significantly reduced resolution for space reasons (bitmapped postscript or jpg

Model Checking CTL is Almost Always Inherently Sequential

The model checking problem for CTL is known to be P-complete (Clarke, Emerson, and Sistla (1986), see Schnoebelen (2002)). We consider fragments of CTL obtained by restricting the use of temporal modalities or the use of negations---restrictions already studied for LTL by Sistla and Clarke (1985) and Markey (2004). For all these fragments, except for the trivial case without any temporal operator, we systematically prove model checking to be either inherently sequential (P-complete) or very efficiently parallelizable (LOGCFL-complete). For most fragments, however, model checking for CTL is already P-complete. Hence our results indicate that, in cases where the combined complexity is of relevance, approaching CTL model checking by parallelism cannot be expected to result in any significant speedup. We also completely determine the complexity of the model checking problem for all fragments of the extensions ECTL, CTL+, and ECTL+

Treatment decision-making among men with lower urinary tract symptoms:A qualitative study of men’s experiences with recommendations for patient-centred practice

Aims: To inform and guide patient-centred care for men with lower urinary tract symptoms (LUTS), by providing in-depth qualitative evidence regarding men’s perspectives on treatment decision-making for LUTS.Methods: Interview study of men recruited from 26 English urology departments. Purposive sampling captured, surgical/non-surgical treatment decisions, and diversity in demographics and symptom burden, in men who had urodynamics and those who did not. After diagnostic assessments, men were interviewed either pre-treatment, or after LUTS surgery. Thematic analysis was conducted. Participants’ descriptions of how LUTS treatment decisions were made were categorised as patient-led, doctor-led, or shared.Results: 41 men participated (25 pre-treatment, 16 post-surgery), ages 52-89. 20/41 described the treatment decision as shared with their consultant, 14 as doctor-led, and 7 as patient-led. There was no obvious association between treatment decision-making style and patients’ satisfaction with either clinicians’ role in their decision or their treatment decision. Incomplete or rushed discussions and misperceptions of LUTS and its treatment were reported, indicating a risk of suboptimal decision-making support by clinicians. As well as clinician opinion, men’s treatment decision-making was influenced by the results of urological assessments, comparing current symptoms with possible side-effects of surgery, and others’ experiences and opinions. Conclusions: Men with LUTS report and prefer different kinds of decision-making support from their clinicians, who must tailor their input to patients’ preferences and needs. Patients’ treatment decision-making involves multiple factors and can be challenging, and areas of inadequate clinician support were identified. Recommendations for patient-centred consultations about LUTS treatment are presented. <br/

Confronting the Superbubble Model with X-ray Observations of 30 Dor C

We present an analysis of XMM-Newton observations of the superbubble 30 Dor C and compare the results with the predictions from the standard wind-blown bubble model. We find that the observed X-ray spectra cannot be fitted satisfactorily with the model alone and that there is evidence for nonthermal X-ray emission, which is particularly important at > 4 keV. The total unabsorbed 0.1-10 keV luminosities of the eastern and western parts of the bubble are ~3 10^36 erg/s and ~5 10^36 erg/s, respectively. The unabsorbed 0.1-10 keV luminosity of the bubble model is 4 10^36 erg/s and so the power-law component contributes between 1/3 and 1/2 to the total unabsorbed luminosity in this energy band. The nature of the hard nonthermal emission is not clear, although recent supernovae in the bubble may be responsible. We expect that about one or two core-collapse supernovae could have occured and are required to explain the enrichment of the hot gas, as evidenced by the overabundance of alpha-elements by a factor of 3, compared to the mean value of 0.5 solar for the interstellar medium in the Large Magellanic Cloud. As in previous studies of various superbubbles, the amount of energy currently present in 30 Dor C is significantly less than the expected energy input from the enclosed massive stars over their lifetime. We speculate that a substantial fraction of the input energy may be radiated in far-infrared by dust grains, which are mixed with the hot gas because of the thermal conduction and/or dynamic mixing.Comment: 25 pages, 4 figures. To appear in The Astrophysical Journal, August 20, 2004 issu

Statistical mechanics of the vertex-cover problem

We review recent progress in the study of the vertex-cover problem (VC). VC belongs to the class of NP-complete graph theoretical problems, which plays a central role in theoretical computer science. On ensembles of random graphs, VC exhibits an coverable-uncoverable phase transition. Very close to this transition, depending on the solution algorithm, easy-hard transitions in the typical running time of the algorithms occur. We explain a statistical mechanics approach, which works by mapping VC to a hard-core lattice gas, and then applying techniques like the replica trick or the cavity approach. Using these methods, the phase diagram of VC could be obtained exactly for connectivities $c<e$, where VC is replica symmetric. Recently, this result could be confirmed using traditional mathematical techniques. For $c>e$, the solution of VC exhibits full replica symmetry breaking. The statistical mechanics approach can also be used to study analytically the typical running time of simple complete and incomplete algorithms for VC. Finally, we describe recent results for VC when studied on other ensembles of finite- and infinite-dimensional graphs.Comment: review article, 26 pages, 9 figures, to appear in J. Phys. A: Math. Ge