982 research outputs found
A Bayesian approach to the estimation of maps between riemannian manifolds
Let \Theta be a smooth compact oriented manifold without boundary, embedded
in a euclidean space and let \gamma be a smooth map \Theta into a riemannian
manifold \Lambda. An unknown state \theta \in \Theta is observed via
X=\theta+\epsilon \xi where \epsilon>0 is a small parameter and \xi is a white
Gaussian noise. For a given smooth prior on \Theta and smooth estimator g of
the map \gamma we derive a second-order asymptotic expansion for the related
Bayesian risk. The calculation involves the geometry of the underlying spaces
\Theta and \Lambda, in particular, the integration-by-parts formula. Using this
result, a second-order minimax estimator of \gamma is found based on the modern
theory of harmonic maps and hypo-elliptic differential operators.Comment: 20 pages, no figures published version includes correction to eq.s
31, 41, 4
A randomised control trial of corneal vs. scleral rigid gas permeable contact lenses for ectatic corneal disorders
Introduction. Keratoconus and related corneal ectatic disorders are conditions characterised by a misshapen cornea. Keratoconus is typically managed with corneal rigid gas permeable contact lenses (CRGPcl) and when these are unsuccessful patients may be fitted with the much larger scleral rigid gas permeable contact lenses (SRGPcl). It has been hypothesised that due to their superior performance, SRGPcl might be considered as the first option for management of keratoconus and the present research investigates this hypothesis.
Purpose. To assess the visual performance, vision related quality of life (Qol) and subjective perception of vision (SPV) and the subjective perception of comfort (SPC) in two contact lens types: CRGPcl and SRGPcl, in successful CRGPcl wearers with keratoconus (and related ectatic corneal disorders).
Methods. Thirty-four successful CRGPcl wearers, with keratoconus or related disorders, participated in a crossover randomised control trial (RCT). This research was approved by the National Research Ethics Service (NRES) of London-Camden and Kingâs Cross as well as the research ethics committees of London South Bank University (LSBU) and the Institute of Optometry. Participants were randomised into two groups, group 1 (sequence AB) were fitted with new CRGPcl and after a washout period, in which habitual CRGPcl were worn, were fitted with and crossed-over to SRGPcl. Group 2 were first fitted with SRGPcl and after a washout period were fitted with and crossed-over to new CRGPcl (sequence BA). Data for experimental outcome measures were collected three times: first on recruitment in habitual CRGPcl, and once after each period in experimental CRGPcl and SRGPcl. The outcome measures were: The Early Treatment Diabetic Retinopathy (ETDRS) log of minimum angle of resolution (logMAR) best corrected visual acuity (BCVA); the VectorVision 1000E contrast sensitivity function (CSF), expressed in both numeric and log contrast sensitivity (logCS); the National Eye Institute Visual Function Questioannaire-25 (NEI-VFQ) to assess the visual Qol; and the reported SPV and SPC, recorded on a Likert-like scale from 1â10. The final measure was at the end of the second period, each participant selected the preferred lens type, out of the two experimental lenses, for future habitual use.
Results. Thirty participants completed the trial, 13 in group 1 and 17 in group 2. Randomisation demographics revealed no significant differences between the two randomised groups except in corneal pachymetry (thickness): group 1[Mean 423.2 (±45.1)], group 2 [Mean 462.8 (±44.7)] (p= 0.002).
The SPC in the experimental lenses and the SPC in the experimental CRGPcl in participants who selected CRGPcl as the habitual lens for future use, were the only measures, which exhibited significant differences. The SPC was not-normally distributed in SRGPcl, [Median=9.0, IQR=2.0, Mean=8.85, (±1.10)] and normally distributed in CRGPcl [Mean=7.78, (±1.45), Median=8.0, IQR=2.0]. The intra-subject period differences in SPC between group 1 (Median=1.0) and group 2 (Median=-1.0), revealed significantly higher scores in SRGPcl (p=0.002), rejecting H0. The preferred habitual lens choice outcome was: 14 participants (47%) chose SRGPcl and 16 (52%) chose CRGPcl. Higher SPC scores in the experimental CRGPcl, were found in participants who chose CRGPcl, (p=0.006) and (p=0.009) by independent samples t-test and Mann-Whitney U test respectively, rejecting H0. The only significant carryover effect was found in the logCS scores (p=0.019), no other outcome was found to have significant carryover or period effects.
No other outcome was found to have significant differences between the two lens types, supporting H0, with respect to: the ETDRS logMAR BCVA, the CSF numeric and logCS, the specific logCS at 6 cycles per degree (CPD), the 12 domains of the NEI-VFQ, the specific ocular pain domain of the NEI-VFQ and the SPV.
Conclusion. The research population exhibited significantly better comfort in SRGPcl compared with CRGPcl, as measured by the Levit Subjective Comfort Scale (LSCS). Furthermore, participants who chose to remain in CRGPcl had significantly higher LSCS scores in CRGPcl than those who chose SRGPcl. Successful CRGPcl wearers whose LSCS in CRGPcl is < 7 are likely to achieve better comfort / tolerance with SRGPcl. No significant differences were found in this research population between the two experimental lens types, in the visual outcomes of logMAR, logCS and SPV and no significant difference was found in the visual Qol outcomes in the 12 domains of the NIE-VFQ. This research indicates that on average, successful CRGPcl wearers find SRGPcl more comfortable and there should be no visual and visual Qol advantage or disadvantage in refitting successful keratoconic CRGPcl wearers with SRGPcl and vice versa
A randomised control trial of corneal vs. scleral rigid gas permeable contact lenses for ectatic corneal disorders
Introduction. Keratoconus and related corneal ectatic disorders are conditions characterised by a misshapen cornea. Keratoconus is typically managed with corneal rigid gas permeable contact lenses (CRGPcl) and when these are unsuccessful patients may be fitted with the much larger scleral rigid gas permeable contact lenses (SRGPcl). It has been hypothesised that due to their superior performance, SRGPcl might be considered as the first option for management of keratoconus and the present research investigates this hypothesis.
Purpose. To assess the visual performance, vision related quality of life (Qol) and subjective perception of vision (SPV) and the subjective perception of comfort (SPC) in two contact lens types: CRGPcl and SRGPcl, in successful CRGPcl wearers with keratoconus (and related ectatic corneal disorders).
Methods. Thirty-four successful CRGPcl wearers, with keratoconus or related disorders, participated in a crossover randomised control trial (RCT). This research was approved by the National Research Ethics Service (NRES) of London-Camden and Kingâs Cross as well as the research ethics committees of London South Bank University (LSBU) and the Institute of Optometry. Participants were randomised into two groups, group 1 (sequence AB) were fitted with new CRGPcl and after a washout period, in which habitual CRGPcl were worn, were fitted with and crossed-over to SRGPcl. Group 2 were first fitted with SRGPcl and after a washout period were fitted with and crossed-over to new CRGPcl (sequence BA). Data for experimental outcome measures were collected three times: first on recruitment in habitual CRGPcl, and once after each period in experimental CRGPcl and SRGPcl. The outcome measures were: The Early Treatment Diabetic Retinopathy (ETDRS) log of minimum angle of resolution (logMAR) best corrected visual acuity (BCVA); the VectorVision 1000E contrast sensitivity function (CSF), expressed in both numeric and log contrast sensitivity (logCS); the National Eye Institute Visual Function Questioannaire-25 (NEI-VFQ) to assess the visual Qol; and the reported SPV and SPC, recorded on a Likert-like scale from 1â10. The final measure was at the end of the second period, each participant selected the preferred lens type, out of the two experimental lenses, for future habitual use.
Results. Thirty participants completed the trial, 13 in group 1 and 17 in group 2. Randomisation demographics revealed no significant differences between the two randomised groups except in corneal pachymetry (thickness): group 1[Mean 423.2 (±45.1)], group 2 [Mean 462.8 (±44.7)] (p= 0.002).
The SPC in the experimental lenses and the SPC in the experimental CRGPcl in participants who selected CRGPcl as the habitual lens for future use, were the only measures, which exhibited significant differences. The SPC was not-normally distributed in SRGPcl, [Median=9.0, IQR=2.0, Mean=8.85, (±1.10)] and normally distributed in CRGPcl [Mean=7.78, (±1.45), Median=8.0, IQR=2.0]. The intra-subject period differences in SPC between group 1 (Median=1.0) and group 2 (Median=-1.0), revealed significantly higher scores in SRGPcl (p=0.002), rejecting H0. The preferred habitual lens choice outcome was: 14 participants (47%) chose SRGPcl and 16 (52%) chose CRGPcl. Higher SPC scores in the experimental CRGPcl, were found in participants who chose CRGPcl, (p=0.006) and (p=0.009) by independent samples t-test and Mann-Whitney U test respectively, rejecting H0. The only significant carryover effect was found in the logCS scores (p=0.019), no other outcome was found to have significant carryover or period effects.
No other outcome was found to have significant differences between the two lens types, supporting H0, with respect to: the ETDRS logMAR BCVA, the CSF numeric and logCS, the specific logCS at 6 cycles per degree (CPD), the 12 domains of the NEI-VFQ, the specific ocular pain domain of the NEI-VFQ and the SPV.
Conclusion. The research population exhibited significantly better comfort in SRGPcl compared with CRGPcl, as measured by the Levit Subjective Comfort Scale (LSCS). Furthermore, participants who chose to remain in CRGPcl had significantly higher LSCS scores in CRGPcl than those who chose SRGPcl. Successful CRGPcl wearers whose LSCS in CRGPcl is < 7 are likely to achieve better comfort / tolerance with SRGPcl. No significant differences were found in this research population between the two experimental lens types, in the visual outcomes of logMAR, logCS and SPV and no significant difference was found in the visual Qol outcomes in the 12 domains of the NIE-VFQ. This research indicates that on average, successful CRGPcl wearers find SRGPcl more comfortable and there should be no visual and visual Qol advantage or disadvantage in refitting successful keratoconic CRGPcl wearers with SRGPcl and vice versa
Translation of Levchenko, N. G. 1962. Infection by sarcosporidia (genus \u3ci\u3eSarcocystis\u3c/i\u3e) in farm animals of southeast Kazakhstan [=Porazhenie sarkosporidiyami (roda \u3ci\u3eSarcocystis\u3c/i\u3e) sel\u27skokhozyaistvennykh zhivotnykh yugo-vostoka Kazakhstana]. In Boev, S. N. et al., editors. \u3ci\u3eParasites of farm animals in Kazakhstan\u3c/i\u3e, I. [= \u3ci\u3eParazity sel\u27skhokozyaistvennykh zhivotnykh Kazakhstana\u3c/i\u3e, I]. \u3ci\u3eIzdat. Akademie Nauk Kazakh SSR\u3c/i\u3e, Alma-Ata, Kazakh SSR, pp. 56-62
Conclusions
Farm animals in southeast Kazakhstan are widely infected with sarcosporidia: 96.9% of the sheep, 88% of the cattle, 70% of the camels, and 40% of the swine.
The muscles most often and most heavily infected are: in sheep, the heart, diaphragm, and median buttock muscle; in cattle, the heart and esophagus; in camels, the esophagus, diaphragm, and median buttock muscle; in swine, the heart, diaphragm, and median buttock.
The most objective data on infection of animals can be obtained by studying a minimum of 3 or 4 muscles of different muscular systems simultaneously.
Heavy infection of muscles by sarcosporidia, especially in the cardiac muscle, cannot but exercise a destructive effect on the body as a whole.
Translation 22, College of Veterinary Medicine, University of Illinois, Urbana, Illinois, United States, December 17, 1969 (10 pages)
Translation of Levchenko, N. G. 1962. Infection by sarcosporidia (genus Sarcocystis) in farm animals of southeast Kazakhstan [=Porazhenie sarkosporidiyami (roda Sarcocystis) sel\u27skokhozyaistvennykh zhivotnykh yugo-vostoka Kazakhstana]. In Boev, S. N. et al., editors. Parasites of farm animals in Kazakhstan, I. [= Parazity sel\u27skhokozyaistvennykh zhivotnykh Kazakhstana, I]. Izdat. Akademie Nauk Kazakh SSR, Alma-Ata, Kazakh SSR, pp. 56-62
Translated from Russian to English by Frederick K. Plous, Jr., and edited by Norman D. Levine (notated NDL:cml
Translation of Levit, A. V. 1962. Some results of a study of domestic animals for toxoplasmosis in the Alma-Ata Oblast [= Obsledovaniya no toksoplazmoz domashnikh zhivotnykh v Alma-Atinstoi Oblasti]. In Boev, S. N., et al., editors. \u3ci\u3eParasites of farm animals in Kazakhstan\u3c/i\u3e, I [= \u3ci\u3eParazity sel\u27skhozyaistvennykh zhivotnykh Kazakhstana\u3c/i\u3e, I]. \u3ci\u3eIzdat. Akademie Nauk Kazakh SSR\u3c/i\u3e, Alma-Ata, pp. 20-25
Conclusions
1. Group biological probes on white mice were used to examine 64 dogs and 224 domestic cats. Toxoplasma was isolated from dogs in one test and from cats in another. In one case Toxoplasma was observed in a cerebrospinal fluid precipitate from cats.
2. In a CFR examination of blood sera from 1,132 domestic animals for toxoplasmosis, positive results were obtained from 25 (37.5%) dog sera, 28 (57.1%) rabbit sera, and 260 (33.4%) cattle sera.
3. In a CFR investigation of sera. from white mice used in bioprobes on domestic cats, toxoplasmosis antibodies were observed in 8 out of 31 bioprobes.
Translation number 20, College of Veterinary Medicine, University of Illinois, Urbana, Illinois, United States, December 5, 1969 (9 pages)
Translation of Levit, A. V. 1962. Some results of a study of domestic animals for toxoplasmosis in the Alma-Ata Oblast [= Obsledovaniya no toksoplazmoz domashnikh zhivotnykh v Alma-Atinstoi Oblasti]. In Boev, S. N., et al., editors. Parasites of farm animals in Kazakhstan, I [= Parazity sel\u27skhozyaistvennykh zhivotnykh Kazakhstana, I]. Izdat. Akademie Nauk Kazakh SSR, Alma-Ata, pp. 20~25
Translated from Russian to English by Freerick K. Plous, Jr., and edited by Norman D. Levine (notated NDL:cml
Semiclassical treatment of fusion processes in collisions of weakly bound nuclei
We describe a semiclassical treatment of nuclear fusion reactions involving
weakly bound nuclei. In this treatment, the complete fusion probabilities are
approximated by products of two factors: a tunneling probability and the
probability that the system is in its ground state at the strong absorption
radius. We investigate the validity of the method in a schematic two-channel
application, where the channels in the continuum are represented by a single
resonant state. Comparisons with full coupled-channels calculations are
performed. The agreement between semiclassical and quantal calculations isquite
good, suggesting that the procedure may be extended to more sophisticated
discretizations of the continuum.Comment: 11 pages, 5 figure
Conceptual Categories Expressed by Terms of Astrophysics
The results of research in the field of terminology studies are presented. The content of synonymic terms conceptual category , type of concept , category of mental construct that are the key terms in this study is revealed. The typology of conceptual categories is discussed. The existing classifications of types of concepts, verbalized by the terms are given. The main objective of the study is a detailed examination of the typology of concepts introduced in the terminology of astrophysics. Attempt to divide the terms into categories distinguished to this area of scientific knowledge is made. The percentage of terminological lexical units that appear in each of the categories is given. The paper identifies the most and the least frequent conceptual categories, which are expressed in the terms belonging to a given field of scientific knowledge. It is argued that the difference in the percentage of verbalization of the types of concepts are determined primarily by specific sub-language for special purposes, by example of which the study is conducted. The importance of studying the typology of terminological units for the analysis of the system organization of specialized vocabulary is proved. The prospects for further research in this direction are revealed. Material for analysis were Russian terminological lexical units extracted from terminological dictionaries and encyclopedias, as well as articles on specialized Internet-resources
Low temperature dielectric relaxation in ordinary perovskite ferroelectrics: enlightenment from high-energy x-ray diffraction
Ordinary ferroelectrics exhibit a second order phase transition that is characterized by a sharp peak in the dielectric permittivity at a frequency-independent temperature. Furthermore, these materials show a low temperature dielectric relaxation that appears to be a common behavior of perovskite systems. Tetragonal lead zirconate titanate is used here as a model system in order to explore the origin of such an anomaly, since there is no consensus about the physical phenomenon involved in it. Crystallographic and domain structure studies are performed from temperature dependent synchrotron x-ray diffraction measurement. Results indicate that the dielectric relaxation cannot be associated with crystallographic or domain configuration changes. The relaxation process is then parameterized by using the VogelâFulcherâTammann phenomenological equation. Results allow us to hypothesize that the observed phenomenon is due to changes in the dynamic behavior of the ferroelectric domains related to the fluctuation of the local polarization.Postprint (author's final draft
On the active site of elastase: Partial mapping by means of specific peptide substrates
AbstractRNase-S peptide as well as some related octa- and hexapeptides were found to be highly, reactive substrates of porcine elastase (e.g. Ala4-Lys-Phe: Km = 4500 Mâ1, kcat = 32 secâ1, C = 1.4 Ă 105 Mâ1 secâ1). Comparison of the various peptides led to the conclusion that the active site of porcine elastase is composed of 6â7 subsites (c.f. [1]). Preliminary mapping shows that subsites S2, SâČ1 and SâČ2 have hydrophobic character. Occupation of subsite S4 by the substrate is important for efficient hydrolysis. Binding at this subsite was found to be stereospecific
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