127 research outputs found

    Form factor expansion of the row and diagonal correlation functions of the two dimensional Ising model

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    We derive and prove exponential and form factor expansions of the row correlation function and the diagonal correlation function of the two dimensional Ising model

    The diagonal Ising susceptibility

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    We use the recently derived form factor expansions of the diagonal two-point correlation function of the square Ising model to study the susceptibility for a magnetic field applied only to one diagonal of the lattice, for the isotropic Ising model. We exactly evaluate the one and two particle contributions χd(1)\chi_{d}^{(1)} and χd(2)\chi_{d}^{(2)} of the corresponding susceptibility, and obtain linear differential equations for the three and four particle contributions, as well as the five particle contribution χd(5)(t){\chi}^{(5)}_d(t), but only modulo a given prime. We use these exact linear differential equations to show that, not only the russian-doll structure, but also the direct sum structure on the linear differential operators for the n n-particle contributions χd(n)\chi_{d}^{(n)} are quite directly inherited from the direct sum structure on the form factors f(n) f^{(n)}. We show that the nth n^{th} particle contributions χd(n)\chi_{d}^{(n)} have their singularities at roots of unity. These singularities become dense on the unit circle ∣sinh⁥2Ev/kTsinh⁥2Eh/kT∣=1|\sinh2E_v/kT \sinh 2E_h/kT|=1 as n→∞ n\to \infty.Comment: 18 page

    Throat related symptoms and voice: development of an instrument for self assessment of throat-problems

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    <p>Abstract</p> <p>Background</p> <p>Symptoms from throat (sensation of globus; frequent throat clearing; irritated throat) are common in patients referred to voice clinics and to ENT specialists. The relation to symptoms of voice discomfort is unclear and in some cases patients do not have voice problems at all. Instruments for patients' self-reporting of symptoms, and assessment of handicap, such as the Voice Handicap Index (VHI), are in common use in voice clinics. Symptoms from throat are however only marginally covered. Purpose: To develop and evaluate an instrument that could make the patients' estimation of symptoms from the throat possible. Further to facilitate the consideration of the relation between throat- and voice problems with the Throat subscale together with a Swedish translation of the Voice Handicap Index. Finally to try the VHI with the Throat subscale: the VHI-T, for test-retest reliability and validity.</p> <p>Methods</p> <p>A subscale with 10 throat related items was developed for appliance with the VHI. The VHI was translated to Swedish and retranslated to English. The questionnaire was tried in two phases on a total of 23+144 patients and 12+58 voice healthy controls. The reliability was calculated with Cronbach's alpha, ICC and Pearson's correlation coefficient. The validity was estimated by independent T-test.</p> <p>Results</p> <p>The difference in VHI-T scores between the patients and the voice-healthy controls was significant (<it>p </it>= < 0,01) and there was a good correlation of the test- retest occasions. The reliability testing of the entire questionnaire showed an alpha value of <it>r </it>= 0,90 and that for the Throat subscale separately a value of <it>r </it>= 0,87 which shows a high degree of reliability.</p> <p>Conclusions</p> <p>For the estimation of self-perceived throat and voice problems the scale on throat related problems together with the present Swedish translation of the Voice Handicap Index, (VHI) the VHI-Throat, proves to be a valid and reliable instrument. The throat subscale seems to help revealing a category of symptoms that are common in our patients. These are symptoms that have not earlier been possible to cover with the questionnaires designed for use in the voice clinic.</p

    Singularities of nn-fold integrals of the Ising class and the theory of elliptic curves

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    We introduce some multiple integrals that are expected to have the same singularities as the singularities of the n n-particle contributions χ(n)\chi^{(n)} to the susceptibility of the square lattice Ising model. We find the Fuchsian linear differential equation satisfied by these multiple integrals for n=1,2,3,4 n=1, 2, 3, 4 and only modulo some primes for n=5 n=5 and 6 6, thus providing a large set of (possible) new singularities of the χ(n)\chi^{(n)}. We discuss the singularity structure for these multiple integrals by solving the Landau conditions. We find that the singularities of the associated ODEs identify (up to n=6n= 6) with the leading pinch Landau singularities. The second remarkable obtained feature is that the singularities of the ODEs associated with the multiple integrals reduce to the singularities of the ODEs associated with a {\em finite number of one dimensional integrals}. Among the singularities found, we underline the fact that the quadratic polynomial condition 1+3w+4w2=0 1+3 w +4 w^2 = 0, that occurs in the linear differential equation of χ(3) \chi^{(3)}, actually corresponds to a remarkable property of selected elliptic curves, namely the occurrence of complex multiplication. The interpretation of complex multiplication for elliptic curves as complex fixed points of the selected generators of the renormalization group, namely isogenies of elliptic curves, is sketched. Most of the other singularities occurring in our multiple integrals are not related to complex multiplication situations, suggesting an interpretation in terms of (motivic) mathematical structures beyond the theory of elliptic curves.Comment: 39 pages, 7 figure

    Ninth and Tenth Order Virial Coefficients for Hard Spheres in D Dimensions

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    We evaluate the virial coefficients B_k for k<=10 for hard spheres in dimensions D=2,...,8. Virial coefficients with k even are found to be negative when D>=5. This provides strong evidence that the leading singularity for the virial series lies away from the positive real axis when D>=5. Further analysis provides evidence that negative virial coefficients will be seen for some k>10 for D=4, and there is a distinct possibility that negative virial coefficients will also eventually occur for D=3.Comment: 33 pages, 12 figure

    Effect of Storage Temperature on Structure and Function of Cultured Human Oral Keratinocytes

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    Purpose/Aims To assess the effect of storage temperature on the viability, phenotype, metabolism, and morphology of cultured human oral keratinocytes (HOK). Materials and Methods Cultured HOK cells were stored in HEPES- and sodium bicarbonate-buffered Minimum Essential Medium (MEM) at nine temperatures in approximately 4°C increments from 4°C to 37°C for seven days. Cells were characterized for viability by calcein fluorescence, phenotype retention by immunocytochemistry, metabolic parameters (pH, glucose, lactate, and O2) within the storage medium by blood gas analysis, and morphology by scanning electron microscopy and light microscopy. Results: Relative to the cultured, but non-stored control cells, a high percentage of viable cells were retained only in the 12°C and 16°C storage groups (85%±13% and 68%±10%, respectively). Expression of ABCG2, Bmi1, C/EBPΎ, PCNA, cytokeratin 18, and caspase-3 were preserved after storage in the 5 groups between 4°C and 20°C, compared to the non-stored control. Glucose, pH and pO2 in the storage medium declined, whereas lactate increased with increasing storage temperature. Morphology was best preserved following storage of the three groups between 12°C, 16°C, and 20°C. Conclusion: We conclude that storage temperatures of 12°C and 16°C were optimal for maintenance of cell viability, phenotype, and morphology of cultured HOK. The storage method described in the present study may be applicable for other cell types and tissues; thus its significance may extend beyond HOK and the field of ophthalmology

    Determining the interviewer effect on CQ Index outcomes: a multilevel approach

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    <p>Abstract</p> <p>Background</p> <p>The CQ Index for the elderly, a quality-of-care questionnaire administered by conducting interviews, is used to assess clients' experiences in Dutch nursing homes and homes for the elderly. This article describes whether inter-interviewer differences influence the perceived quality of healthcare services reported by residents, the size of this interviewer effect and the influence of the interviewer characteristics on CQ Index dimensions for public reporting.</p> <p>Methods</p> <p>Data from 4345 questionnaires was used. Correlations were calculated, reliability analyses were performed, and a multilevel analysis was used to calculate the degree of correlation between two interviewers within one health care institution. Five models were constructed and the Intra Class Correlation (ICC) was calculated. Healthcare institutions were given 1-5 stars on every quality dimensions (1 = worst and 5 = best), adjusted for resident and interviewer characteristics. The effect of these characteristics on the assignment of the stars was investigated.</p> <p>Results</p> <p>In a multilevel approach, the ICC showed a significant amount of variance on five quality dimensions. Of the interviewer characteristics, only previous interviewing experience, the reason of interviewing and general knowledge of health care had a significant effect on the quality dimensions. Adjusting for interviewer characteristics did not affect the overall star assignment to the institutions regarding 7 of 12 quality dimensions. For the other five dimensions (Shared decision-making, Meals, Professional competency, Autonomy, and Availability of personnel) a minor effect was found.</p> <p>Conclusions</p> <p>We have shown that training, the use of experienced interviewers, written instructions, supervision and educational meetings do not automatically prevent interviewer effects. While the results of this study can be used to improve the quality of services provided by these institutions, several CQ index dimensions should be interpreted with caution for external purposes (accountability and transparency).</p

    Development of an international survey attitude scale: measurement equivalence, reliability, and predictive validity

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    Declining response rates worldwide have stimulated interest in understanding what may be influencing this decline and how it varies across countries and survey populations. In this paper, we describe the development and validation of a short 9-item survey attitude scale that measures three important constructs, thought by many scholars to be related to decisions to participate in surveys, that is, survey enjoyment, survey value, and survey burden. The survey attitude scale is based on a literature review of earlier work by multiple authors. Our overarching goal with this study is to develop and validate a concise and effective measure of how individuals feel about responding to surveys that can be implemented in surveys and panels to understand the willingness to participate in surveys and improve survey effectiveness. The research questions relate to factor structure, measurement equivalence, reliability, and predictive validity of the survey attitude scale. The data came from three probability-based panels: the German GESIS and PPSM panels and the Dutch LISS panel. The survey attitude scale proved to have a replicable three-dimensional factor structure (survey enjoyment, survey value, and survey burden). Partial scalar measurement equivalence was established across three panels that employed two languages (German and Dutch) and three measurement modes (web, telephone, and paper mail). For all three dimensions of the survey attitude scale, the reliability of the corresponding subscales (enjoyment, value, and burden) was satisfactory. Furthermore, the scales correlated with survey response in the expected directions, indicating predictive validity

    Targeted analysis of four breeds narrows equine Multiple Congenital Ocular Anomalies locus to 208 kilobases

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    The syndrome Multiple Congenital Ocular Anomalies (MCOA) is the collective name ascribed to heritable congenital eye defects in horses. Individuals homozygous for the disease allele (MCOA phenotype) have a wide range of eye anomalies, while heterozygous horses (Cyst phenotype) predominantly have cysts that originate from the temporal ciliary body, iris, and/or peripheral retina. MCOA syndrome is highly prevalent in the Rocky Mountain Horse but the disease is not limited to this breed. Affected horses most often have a Silver coat color; however, a pleiotropic link between these phenotypes is yet to be proven. Locating and possibly isolating these traits would provide invaluable knowledge to scientists and breeders. This would favor maintenance of a desirable coat color while addressing the health concerns of the affected breeds, and would also provide insight into the genetic basis of the disease. Identical-by-descent mapping was used to narrow the previous 4.6-Mb region to a 264-kb interval for the MCOA locus. One haplotype common to four breeds showed complete association to the disease (Cyst phenotype, n = 246; MCOA phenotype, n = 83). Candidate genes from the interval, SMARCC2 and IKZF4, were screened for polymorphisms and genotyped, and segregation analysis allowed the MCOA syndrome region to be shortened to 208 kb. This interval also harbors PMEL17, the gene causative for Silver coat color. However, by shortening the MCOA locus by a factor of 20, 176 other genes have been unlinked from the disease and only 15 genes remain
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