Accelerating Lattice Quantum Field Theory Calculations via Interpolator Optimization Using Noisy Intermediate-Scale Quantum Computing.

The only known way to study quantum field theories in nonperturbative regimes is using numerical calculations regulated on discrete space-time lattices. Such computations, however, are often faced with exponential signal-to-noise challenges that render key physics studies untenable even with next generation classical computing. Here, a method is presented by which the output of small-scale quantum computations on noisy intermediate-scale quantum era hardware can be used to accelerate larger-scale classical field theory calculations through the construction of optimized interpolating operators. The method is implemented and studied in the context of the 1+1-dimensional Schwinger model, a simple field theory which shares key features with the standard model of nuclear and particle physics.

Nucleon Structure Functions from Operator Product Expansion on the Lattice.

Deep-inelastic scattering, in the laboratory and on the lattice, is most instructive for understanding how the nucleon is built from quarks and gluons. The long-term goal is to compute the associated structure functions from first principles. So far this has been limited to model calculations. In this Letter we propose a new method to compute the structure functions directly from the virtual, all-encompassing Compton amplitude, utilizing the operator product expansion. This overcomes issues of renormalization and operator mixing, which so far have hindered lattice calculations of power corrections and higher moments.

Determination of the strange nucleon form factors.

The strange contribution to the electric and magnetic form factors of the nucleon is determined at a range of discrete values of Q^{2} up to 1.4 GeV^{2}. This is done by combining a recent analysis of lattice QCD results for the electromagnetic form factors of the octet baryons with experimental determinations of those quantities. The most precise result is a small negative value for the strange magnetic moment: G_{M}^{s}(Q^{2}=0)=-0.07±0.03µ_{N}. At larger values of Q^{2} both the electric and magnetic form factors are consistent with zero to within 2 standard deviations.

Octet spin fractions and the proton spin problem.

The relatively small fraction of the spin of the proton carried by its quarks presents a major challenge to our understanding of the strong interaction. Traditional efforts to explore this problem have involved new and imaginative experiments and QCD based studies of the nucleon. We propose a new approach to the problem that exploits recent advances in lattice QCD. In particular, we extract values for the spin carried by the quarks in other members of the baryon octet in order to see whether the suppression observed for the proton is a general property or depends significantly on the baryon structure. We compare these results with the values for the spin fractions calculated within a model that includes the effects of confinement, relativity, gluon exchange currents, and the meson cloud required by chiral symmetry, finding a very satisfactory level of agreement given the precision currently attainable.

Coupling of protein and environment fluctuations.

We review the concepts of protein dynamics developed over the last 35years and extend applications of the unified model of protein dynamics to heat flow and spatial fluctuations in hydrated myoglobin (Mb) powders. Differential scanning calorimetry (DSC) and incoherent neutron scattering (INS) data on hydration Mb powders are explained by the temperature-dependence of the hydration-shell ß(h) process measured by dielectric relaxation spectroscopy (DRS). The unified model explains the temperature dependence of DSC and INS data as a kinetic effect due to a fixed experimental time window and a broad distribution of hydration-shell ß(h) fluctuation rates. We review the slaving of large scale protein motions to the bulk solvent α process, and the metastability of Mb molecules in glass forming bulk solvent at low temperatures. This article is part of a Special Issue entitled: "Protein Dynamics: Experimental and Computational Approaches".

Mass of the H dibaryon.

Recent lattice QCD calculations have reported evidence for the existence of a bound state with strangeness -2 and baryon number 2 at quark masses somewhat higher than the physical values. By developing a description of the dependence of this binding energy on the up, down and strange quark masses that allows a controlled chiral extrapolation, we explore the hypothesis that this state is to be identified with the H dibaryon. Taking as input the recent results of the HAL and NPLQCD Collaborations, we show that the H dibaryon is likely to be unbound by 13±14 MeV at the physical point.

The effect of bacteriochlorophyll derivative WST-D and near infrared light on the molecular and fibrillar architecture of the corneal stroma.

A cross-linking technique involving application of Bacteriochlorophyll Derivative WST-11 mixed with dextran (WST-D) to the epithelium-debrided cornea and illumination with Near Infrared (NIR), has been identified as a promising therapy for stiffening pathologically weakened corneas. To investigate its effect on corneal collagen architecture, x-ray scattering and electron microscopy data were collected from paired WST-D/NIR treated and untreated rabbit corneas. The treated eye received 2.5 mg/mL WST-D and was illuminated by a NIR diode laser (755 nm, 10 mW/cm2). An increase in corneal thickness (caused by corneal oedema) occurred at 1-day post-treatment but resolved in the majority of cases within 4 days. The epithelium was fully healed after 6-8 days. X-ray scattering revealed no difference in average collagen interfibrillar spacing, fibril diameter, D-periodicity or intermolecular spacing between treated and untreated specimens. Similarly, electron microscopy images of the anterior and posterior stroma in healed WST-D/NIR corneas and untreated controls revealed no obvious differences in collagen organisation or fibril diameter. As the size and organisation of stromal collagen is closely associated with the optical properties of the cornea, the absence of any large-scale changes following treatment confirms the potential of WST-D/NIR therapy as a means of safely stiffening the cornea.

Immunolocalization of type III collagen in human articular cartilage prepared by high-pressure cryofixation, freeze-substitution, and low-temperature embedding.

We localized Type III collagen by immunogold electron microscopy in resin sections of intact normal and osteoarthritic human articular cartilage. Comparisons of antibody staining between tissue prepared by high-pressure cryofixation and freeze-substitution without fixatives and that exposed to conventional mild chemical fixation with paraformaldehyde showed that dedicated cryotechniques yielded superior preservation of epitopes that are modified by chemical fixation, and simultaneously provided good ultrastructural preservation. Type III collagen was detected with two polyclonal antibodies, one against the triple-helical domain of the molecule and a second against the more antigenic, globular amino pro-peptide domain, which in this collagen is retained in the extracellular matrix after secretion. Positive labeling was seen in association with the major interstitial fibrils, suggesting co-polymerization of Types III and II collagen in cartilage. Type III collagen could not be detected in aldehyde-fixed normal cartilage. In fixed osteoarthritic cartilage, Type III was detectable only when the antibody to the amino pro-peptide was employed. In contrast, high-pressure cryofixation and freeze-substitution preserved epitopes for both antibodies, permitting immunodetection of Type III collagen in normal and osteoarthritic cartilage. Cryotechniques offer exciting possibilities for significantly improving the immunolocalization of collagens and other fixative-sensitive antigens in situ.

Immunolocalization of collagen types II and III in single fibrils of human articular cartilage.

Type II and III fibrillar collagens were localized by immunogold electron microscopy in resin sections of human femoral articular cartilage taken from the upper radial zone in specimens from patients with osteoarthritis. Tissue samples stabilized by high-pressure cryofixation were processed by freeze-substitution, either in acetone containing osmium or in methanol without chemical fixatives, before embedding in epoxy or Lowicryl resin, respectively. Ultrastructural preservation was superior with osmium-acetone, although it was not possible to localize collagens by this method. In contrast, in tissue prepared by low-temperature methods without chemical fixation, collagens were successfully localized with mono- or polyclonal antibodies to the helical (Types II and III) and amino-propeptide (Type III procollagen) domains of the molecule. Dual localization using secondary antibodies labeled with 5- or 10-nm gold particles demonstrated the presence of Types II and III collagen associated within single periodic banded fibrils. Collagen fibrils in articular cartilage are understood to be heteropolymers mainly of Types II, IX, and XI collagen. Our observations provide further evidence for the complexity of these assemblies, with the potential for interactions between at least 11 distinct collagen types as well as several noncollagenous components of the extracellular matrix.

The mechanical properties of the human lens capsule following capsulorhexis or radiofrequency diathermy capsulotomy.

OBJECTIVE: To quantify the biomechanical properties of the capsulotomy edge following continuous-tear circular capsulorhexis (CTCC) or radiofrequency (RF) diathermy capsulotomy. METHODS: A test apparatus was constructed that allowed controlled stretching of capsulotomy edges following CTCC or RF diathermy capsulotomy. The lens contents were removed by phacoemulsification to permit the implantation of probes that exerted a test force on the capsulotomy edge and were moved in diametrically opposite directions using computer-controlled stepping motors. The magnitude of the force was measured during the capsule stretch, which allowed precise determination of the degree of capsular distention at the time of capsular rupture. Selected capsular edges were subsequently examined by scanning electron microscopy. RESULTS: The capsulotomy edge produced by CTCC was significantly stronger (P < .001) than that following RF. The mean (+/-SD) force to achieve capsule rupture was 0.15 +/- 0.06 N with CTCC compared with 0.02 +/- 0.01 N with RF. The mean (+/-SD) increase in the capsulotomy circumference was significantly greater with CTCC at 53% +/- 14.5% compared with RF at 18% +/- 8.5% (P < .001). Scanning electron microscopy disclosed a smooth edge for the CTCC capsulotomy. In contrast, multiple irregularities were seen in the edge following RF. CONCLUSIONS: Continuous-tear circular capsulorhexis provides a stronger capsulotomy and is the preferred method in routine cataract surgery. However, RF diathermy capsulotomy may have a useful role in conditions unfavorable to the safe completion of CTCC.

Microscopical studies of necrotising scleritis. I. Cellular aspects.

Light and electron microscopy were used to examine tissue excised during surgery from eight patients with advanced destructive scleral disease. These comprised two cases of scleromalacia perforans, three cases of anterior necrotising scleritis alone or in conjunction with other systemic diseases, and three cases in which scleritis developed following ocular surgery. It was not possible to distinguish between these three categories by histological or cytopathological criteria. All showed extensive granulomatous infiltration of the conjunctiva, episclera, and sclera by plasma cells and lymphocytes. Mast cells were abundant throughout these inflamed tissues. Examination of scleral stroma from sites in advance of the granuloma revealed active fibroblastic cells in the absence of other inflammatory cells. Fibroblastic transformation of scleral cells may be one of the earliest events in scleral degradation during necrotising disease.

Microscopical studies of necrotising scleritis. II. Collagen degradation in the scleral stroma.

Electron microscopy of tissue excised during surgery in eight cases of advanced anterior necrotising scleritis showed degradation of collagen in the scleral stroma by both intracellular and extracellular mechanisms. In the first of these mechanisms cells resembling active fibroblasts and macrophages were observed in the process of phagocytosis of collagen fibrils into vacuoles associated with dense cytoplasmic granules. In the second mechanism collagen fibrils in large areas of the scleral stroma appeared swollen and unravelled, or completely solubilised, without close association with stromal cells. Both activation and degeneration of stromal fibrocytes were evident in zones of extracellular fibril degradation. These changes appeared to take place prior to invasion of the stroma by cells of the granuloma.

Changes at the periphery of a lesion in necrotising scleritis: anterior segment fluorescein angiography correlated with electron microscopy.

Anterior segment fluorescein angiography in scleral disease reveals highly characteristic changes in the vasculature of the anterior segment associated with necrotising scleritis. The vaso-obliterative changes discovered in this investigation have been correlated with the histopathology in a patient who had to have tissue replaced. Light and electron microscopy of scleral tissue excised from sites of vascular closure detected by fluorescein angiography peripheral to the scleral defect revealed pathological changes in the absence of inflammatory cell infiltration. These changes included vascular stasis, partial vaso-obliteration, and fibroblastic transformation of scleral fibrocytes in association with intra- and extracellular degradation of the collagenous component of the matrix.

Light and electron microscopy of corneal melting syndrome (Mooren's ulcer).

Three patients with corneal melting syndrome of Mooren are described all of whom required lamellar grafting for perforation of the cornea. All these grafts subsequently failed. Tissue excised during grafting was studied by light and electron microscopy. In all cases the conjunctiva contained large numbers of lymphocytes and plasma cells. The limbal cornea showed 3 distinct zones: the deep stroma was intact but contained a prominent macrophage infiltrate; in the mid stroma marked hyperactivity of fibroblastic cells was associated with disorganisation of the corneal lamellae; the outer stroma was heavily vascularised and infiltrated by lymphocytes and plasma cells, with destruction of the collagen matrix. At the advancing, undermined edge of the corneal ulcer the deep stroma was undisturbed, but in the superficial layers accumulation of fibroblastic cells and destruction of collagen was observed. No other cell types were found. All the failed grafts contained fibroblasts which appeared highly active, surrounded by disorganised collagen fibrils. In these patients destruction of both host and graft corneal stroma apparently resulted from the activity of fibroblastic cells.

Improved preservation of human corneal basement membrane following freezing of donor tissue for epikeratophakia.

Current methods for the production of lenticules for epikeratophakia involve rapid freezing, cryolathing, and slow warming of the donor cornea. We have found that this procedure causes structural damage to the epithelial basement membrane in the donor cornea which may subsequently contribute to poor postoperative re-epithelialisation of the implant, leading to graft failure. Endeavouring to overcome these problems, the effects of cryoprotection of donor cornea were investigated, using dimethyl sulphoxide, in conjunction with different cooling and warming rates as part of the protocol for cryolathing. The structural integrity of the epithelial basement membrane zone (BMZ) was then assessed by electron microscopy and by immunofluorescence microscopy using antibodies to types IV and VII collagen, components of the basal lamina and anchoring fibrils respectively, and an antibody to a component of the anchoring filaments. No differences in the pattern of immunostaining for these components were detected, indicating that the composition of the BMZ was unaltered by the different treatment regimens applied. However, electron microscopy showed that preservation of basement membrane ultrastructure was markedly improved when cornea was warmed rapidly rather than slowly, both in cryoprotected and non-cryoprotected tissue. Epithelial cell retention and preservation of stromal architecture appeared superior in cryoprotected samples, while keratocyte structure was heterogeneous throughout the experimental groups. Further work is in progress to assess the efficacy of these protocols in the preservation of keratocyte viability in association with improved basement membrane structure in donor tissue for epikeratophakia.

Self-consciousness, self-esteem, and success-failure as determinants of alcohol consumption in male social drinkers.

An experiment was conducted to test the proposition that alcohol is consumed as a function of the quality of past performances and the individual's level of private self-consciousness. One hundred and twenty male subjects were randomly given success or failure feedback on an intellectual task. They then participated in a separate "wine-tasting" experiment in which they were allowed to regulate alcohol consumption. As predicted, high self-conscious subjects who had received failure feedback drank significantly more wine than did high self-conscious subjects who received success feedback. Consumption by low self-conscious subjects fell between these extremes and did not vary as a function of success and failure. Additional data indicated that these results were mediated by differential sensitivity to the positive or negative implications of success/failure by high and low self-conscious subjects. The results are discussed in terms of their implications for theoretical accounts of the psychological antecedents of alcohol consumption.

Applications of the self-awareness model of alcohol consumption: predicting patterns of use and abuse.

We conducted two studies to test the applicability of a recently proposed self-awareness model of alcohol consumption to patterns of alcohol use outside of the laboratory. In both studies, we predicted that alcohol use would be a joint function of private self-consciousness and personal success or failure. High self-conscious individuals were predicted to drink following personal failure and avoid drinking following personal success in an attempt to control their sensitivity to the self-relevant implications of such events. Consumption by low self-conscious individuals was predicted to be relatively independent of self-relevant events. These predictions were supported in a longitudinal study of relapse following alcoholic detoxification. They were then replicated in a study of adolescent alcohol use and shown to be relatively independent of other significant environmental and behavioral predictors of consumption. Results are discussed in terms of their implications for theories of self-awareness and alcohol use.

The effects of private self-consciousness and perspective taking on satisfaction in close relationships.

We extended the scope of recent studies in which self-awareness and perspective taking have been used as predictors of social competence or adjustment: We analyzed their influence on the satisfaction experienced in monogamous, heterosexual relationships. Members of 131 couples answered questions concerning themselves and their relationships. We predicted that individual differences in private self-consciousness would be positively related to relationship satisfaction because of the greater self-disclosure resulting from that heightened self-attention. Second, we predicted that individual differences in perspective taking would foster relationship satisfaction, independent of any influence of self-disclosure. Both expectations were confirmed. Scores on the private self-consciousness scale were predictive of reported self-disclosure, and self-disclosure was predictive of satisfaction in the relationship. Furthermore, once the influence of self-disclosure was removed, no effect of self-consciousness on satisfaction remained. In contrast, after disclosure was controlled, perspective-taking scores were significantly related to satisfaction and were in fact unrelated to disclosure at all. These findings indicate that two personality characteristics having to do with habitual attention to behavioral tendencies, to emotions, and to motivations significantly enhance the quality of close heterosexual relationships in different ways. Results are discussed in terms of current theory in the related fields.

Emotional reactions to dramatic film stimuli: the influence of cognitive and emotional empathy.

The idea that empathy may best be considered a multidimensional construct, consisting of both cognitive and emotional facets, has recently been gaining in popularity. To date, however, little research explicitly based on such a view has been carried out. We conducted the present experiment to explore the different influences of cognitive and emotional empathy on two types of responses to dramatic stimuli: positive and negative emotional reactions. Consistent with a multidimensional view of empathy, the two types of empathy exhibited different effects; positive emotional reactions were affected primarily by cognitive empathy, and negative emotional reactions were most heavily influenced by emotional empathy. The results are discussed in terms of their relevance to a multidimensional approach to the study of empathic responding.

Factors affecting the ultrasonic properties of equine digital flexor tendons.

The velocity, attenuation and apparent backscattering coefficient of 6-11-MHz ultrasound were measured in three orthogonal directions in equine deep digital flexor (DDF) and superficial digital flexor (SDF) tendons at 0 degree C. Ultrasonic measurements were examined for correlation with tendon water, collagen, DNA and glycosaminoglycans contents, determined by chemical analyses and with structure observed by scanning electron microscopy. The SDF tendon contained more water, more DNA (i.e., more cells), less collagen and less glycosaminoglycans and exhibited lower velocities and attenuations than the DDF tendon. Velocities were governed primarily by the adiabatic bulk modulus and density, perturbed by a highly direction-dependent rigidity. Ultrasound propagating across tendon generated frequency-independent backscattering which appeared to derive from the large interfaces between the fascicles, while along the fibres backscattering varied as f3.62 +/- 0.88 and appeared to derive from small structures such as collagen fibres. The mechanisms by which ultrasound is attenuated by tendon remain unknown.