Strategy for discovering a low-mass Higgs boson at the Fermilab Tevatron

We have studied the potential of the CDF and DZero experiments to discover a low-mass Standard Model Higgs boson, during Run II, via the processes $p\bar{p}$ -> WH -> $\ell\nu b\bar{b}$, $p\bar{p}$ -> ZH -> $\ell^{+}\ell^{-}b\bar{b}$ and $p\bar{p}$ -> ZH ->$\nu \bar{\nu} b\bar{b}$. We show that a multivariate analysis using neural networks, that exploits all the information contained within a set of event variables, leads to a significant reduction, with respect to {\em any} equivalent conventional analysis, in the integrated luminosity required to find a Standard Model Higgs boson in the mass range 90 GeV/c**2 < M_H < 130 GeV/c**2. The luminosity reduction is sufficient to bring the discovery of the Higgs boson within reach of the Tevatron experiments, given the anticipated integrated luminosities of Run II, whose scope has recently been expanded.Comment: 26 pages, 8 figures, 7 tables, to appear in Physical Review D, Minor fixes and revision

Shape of the posterior vitreous chamber in human emmetropia and myopia

PURPOSE: To compare posterior vitreous chamber shape in myopia to that in emmetropia. METHODS: Both eyes of 55 adult subjects were studied, 27 with emmetropia (mean spherical error [MSE] ≥ -0.55; <+0.75 D; mean +0.09 ± 0.36 D) and 28 with myopia (MSE -5.87 ± 2.31 D). Cycloplegic refraction was measured with a Shin Nippon autorefractor and anterior chamber depth and axial length with a Zeiss IOLMaster. Posterior vitreous chamber shapes were determined from T2-weighted magnetic resonance imaging (3.0-T) using procedures previously reported by our laboratory. Three-dimensional surface model coordinates were assigned to nasal, temporal, superior, and inferior quadrants and plotted in two dimensions to illustrate the composite shape of respective quadrants posterior to the second nodal point. Spherical analogues of chamber shape were constructed to compare relative sphericity between refractive groups and quadrants. RESULTS: Differences in shape occurred in the region posterior to points of maximum globe width and were thus in general accord with an equatorial model of myopic expansion. Shape in emmetropia is categorized distinctly as that of an oblate ellipse and in myopia as an oblate ellipse of significantly less degree such that it approximates to a sphere. There was concordance between shape and retinotopic projection of respective quadrants into right, left, superior, and inferior visual fields. CONCLUSIONS: Prolate ellipse posterior chamber shapes were rarely found in myopia, and we propose that spherical shape in myopia may constitute a biomechanical limitation on further axial elongation. Synchronization of quadrant shapes with retinotopic projection suggests that binocular growth is coordinated by processes that operate beyond the optic chiasm

Measurement of Scleral Thickness in Humans Using Anterior Segment Optical Coherent Tomography

Anterior segment optical coherent tomography (AS-OCT, Visante; Zeiss) is used to examine meridional variation in anterior scleral thickness (AST) and its association with refractive error, ethnicity and gender. Scleral cross-sections of 74 individuals (28 males; 46 females; aged between 18-40 years (27.7±5.3)) were sampled twice in random order in 8 meridians: [superior (S), inferior (I), nasal (N), temporal (T), superior-temporal (ST), superior-nasal (SN), inferior-temporal (IT) and inferior-nasal (IN)]. AST was measured in 1mm anterior-toposterior increments (designated the A-P distance) from the scleral spur (SS) over a 6mm distance. Axial length and refractive error were measured with a Zeiss IOLMaster biometer and an open-view binocular Shin-Nippon autorefractor. Intra- And inter-observer variability of AST was assessed for each of the 8 meridians. Mixed repeated measures ANOVAs tested meridional and A-P distance differences in AST with refractive error, gender and ethnicity. Only right eye data were analysed. AST (mean±SD) across all meridians and A-P distances was 725±46μm. Meridian SN was the thinnest (662±57μm) and I the thickest (806 ±60μm). Significant differences were found between all meridians (p<0.001), except S:ST, IT:IN, IT:N and IN:N. Significant differences between A-P distances were found except between SS and 6 mm and between 2 and 4mm. AST measurements at 1mm (682±48 μm) were the thinnest and at 6mm (818±49 μm) the thickest (p<0.001); a significant interaction occurred between meridians and A-P distances (p<0.001). AST was significantly greater (p<0.001) in male subjects but no significant differences were found between refractive error or ethnicity. Significant variations in AST occur with regard to meridian and distance from the SS and may have utility in selecting optimum sites for pharmaceutical or surgical intervention

Conformation of the anterior segment in human myopia.

PURPOSE: Topography of the in vivo anterior segment is of relevance in understanding its role in myopia and in the development of ocular surgical procedures. Using 3D magnetic resonance (MR) images of the human eye, regional variations in surface area (SA) and bulbosity of four anterior segment regions were investigated in association with refractive status (Rx), axial length (AL) and total ocular volume (OV). METHODS: T2-weighted ocular MR images from 43 adults aged 18-40 years (mean ± SD; 28.65 ± 6.20) comprising 20 non-myopes (≥-0.50) 0.57 ± 1.38 and 23 myopes (<-0.50) -6.37 ± 4.23 MSE (D) were collected. 2D representations of each quadrant (superior-temporal [ST], superior-nasal [SN], inferior-temporal [IT] and inferior-nasal [IN]) of the anterior section (3.5-9 mm) were fitted with second-order polynomials. Polynomials were integrated and rotated about the x-axis to generate SA; dividing the SA by 4 provided relative quadrantial SA. The x2 coefficient provides indices of bulbosity. OV was derived from the 3D MRI scans. Rx and AL were measured using cycloplegic autorefraction and the Zeiss IOLMaster, respectively. One- and two-way repeated-measures ANCOVAs tested differences in SA and bulbosity for Rx, gender, ethnicity and age. Pearson's correlation coefficient tested the relationship between MRI-derived metrics and biometry. RESULTS: Significant differences in SA were observed between quadrants (p < 0.001) with differences between ST versus IN, IN versus IT and SN versus IT. An interaction effect (p = 0.01) for Rx suggested smaller temporal (ST and IT) and larger nasal (SN and IN) SA in myopes. AL and myopic Rx were negative correlated (p < 0.05) with SA at IN, SN and IT. OV was significantly associated with SA at ST. Bulbosity showed no regional differences nor an effect of AL or Rx. CONCLUSION: Significant regional variation in SA exists across the anterior segment that is modulated by Rx and AL. It is unclear whether these structural characteristics are a precursor or consequence of myopia and may warrant investigation when developing biomechanical interventions

The Effects of Severe Myopia on the Properties of Sampling Units in Peripheral Retina

SIGNIFICANCE: Poor peripheral visual acuity in myopia may reflect, in part, photoreceptor misalignment with the exit pupil of the eye. We speculate that if such misalignment causes sufficient visual deprivation and/or disrupts retinal feedback processes, it may influence eye growth itself. PURPOSE: It is known that myopic eyes have a reduced peripheral resolution acuity relative to emmetropic eyes, though it remains unclear how mechanical stretching of the retina in myopia impacts on peripheral visual performance. Our aim was to determine how retinal stretching affects the properties of sampling units in peripheral vision. METHODS: Three-dimensional magnetic resonance imaging provided a depiction in vivo of ocular shape, allowing the inter-eye ratio of retinal image surface areas and the relative alignment of surfaces to be determined in our observer, who was unique in having severe myopia in the right eye (~21 D) but only modest myopia in the left (~3 D). Visual performance was assessed for the detection and direction discrimination of drifting sinusoids positioned 40° in the temporal retina. Applying the sampling theorem to our measures, we estimated the density and cut-off frequency of the underlying sampling units. RESULTS: The retinal image surface area of the right eye was 40% larger than that of the left and was rotated 8.9° anticlockwise relative to the left eye's image surface. In agreement with a linear stretch model of myopia, the sampling density of the right eye was reduced by approximately the same ratio as that predicted from the inter-eye MRI data, namely, 1.18. However, the cut-off frequency (cycles/mm) of the right eye was approximately half that of the left, a reduction that cannot be explained solely by a linear areal expansion of retinal sampling units. CONCLUSIONS: Poor peripheral acuity in severe myopia may be caused, at least in part, by receptoral misalignment with the exit pupil

Using public engagement and consultation to inform the development of ageing-and dementia-friendly pharmacies – Innovative practice

This study explored public perceptions about the importance of, and how to create, ageing- and dementia-friendly pharmacists and pharmacies. In September 2016, four focus groups (45 minutes each) were conducted with 16 participants who represented organisations, groups or forums working with and/or for older people and people with dementia in Greater London. Discussions were recorded via handwritten notes and thematically analysed. Participants confirmed the importance of pharmacists and pharmacies being ageing- and dementia-friendly and described variability in whether this is currently the case. Suggested strategies for improvement included targeting communication, pharmacist leadership and shop layout

‘What’s the point in extending your life if this is your life’: A qualitative exploration of pre-surgery, short-term and long-term responses to bariatric surgery

This study examined experiences of weight, physical activity, diet, and quality of life of individuals prior to and following bariatric surgery. Twenty-seven people participated who represented three periods related to bariatric surgery: pre-surgery; short-term post-surgery (i.e., 1–2 years) and long-term post-surgery (i.e., 3–7 years). A qualitative descriptive design was adopted, with data collected through interviews and analysed using thematic analysis. Themes in the pre-surgery period were identified as follows: a) Growing up: Variation by family and ability, b) Weight gain: Transitions, traumas, and triggers; c) Perceptions of self: Hate, loathing, and worthlessness; d) Spiralling weight: Lack of control over vicious cycles of dieting and weight gain, and; e) Surgery: A final and essential lifeline. Short-term post-surgery themes were: a) Physical changes: Rapid weight loss and enhanced health versus hesitation and disappointment; b) Physical activity: Changes in engagement and perceptions despite ongoing barriers; c) Finding oneself: Increased emotional wellbeing, self-concept and confidence, and; d) Quality of life: Renewed physical capabilities and capacity but some continuing challenges. In the long-term following surgery, themes of: a) Weight plateau/regain: Disappointment and feelings of failure, and; b) Excess fat: Frustration and feelings of vulnerability emerged from the data. It is evident that participants go on an extended journey in the years before and after bariatric surgery and experience a range of both positive and negative outcomes. Overall, the findings highlight the importance of practitioners understanding individual’s overall journeys when seeking to help them lose weight and improve psychological health

Accommodation microfluctuations and pupil size during sustained viewing of visual display terminals

Summary Accommodation microfluctuations comprise two dominant frequencies; a low frequency component (LFCi 0.6 Hz) and a high frequency component (1.0 Hz &lt; HFC &lt; 2.1 Hz). In the present experiment we examine accommodation microfluctuations and steady-state pupil responses during sustained viewing of visual display terminals (VDTs). Steady-state accommodation and pupil responses were measured continuously and simultaneously using a modified Canon Autoref R-1 infra-red objective optometer and an Hamamatsu C3160 Perceptscope Video Area Analyser. Measurements were obtained at three time intervals (0, 10 and 20 min) during a 20 min reading task presented on five different displays. With the displays placed at 50 cm, the task was to locate and identify typographical errors in one of five sets of standard text. Five young visually-normal emmetropic subjects with a mean age of 22.5 2 3.0 years participated in the study. Two-way ANOVA revealed no significant variation in the magnitude of the accommodation microfluctuations with either display or task duration, nor was there any significant interaction between these two factors. There was no significant variation in mean pupil diameter with either display or task duration. These measures may have the potential to provide objective information about visual display quality.

Sampling and measurement methods for a study of childhood refractive error in a UK population

International audienceBackground There is a paucity of data describing the prevalence of childhood refractive error in the United Kingdom. The Northern Ireland Childhood Errors of Refraction study, along with its sister study the Aston Eye Study, are the first population-based surveys of children using both random cluster sampling and cycloplegic autorefraction to quantify levels of refractive error in the United Kingdom. Methods Children aged 6-7 years and 12-13 years were recruited from a stratified random sample of primary and post-primary schools, representative of the population of Northern Ireland as a whole. Measurements included assessment of visual acuity, oculomotor balance, ocular biometry and cycloplegic binocular open-field autorefraction. Questionnaires were used to identify putative risk factors for refractive error. Results 399 (57%) of 6-7 years and 669 (60%) of 12-13 years participated. School participation rates did not vary statistically significantly with the size of the school, whether the school is urban or rural, or whether it is in a deprived/non-deprived area. The gender balance, ethnicity and type of schooling of participants are reflective of the Northern Ireland population. Conclusions The study design, sample size and methodology will ensure accurate measures of the prevalence of refractive errors in the target population and will facilitate comparisons with other population-based refractive data

Quantitation of drug sensitivity by human metastatic melanoma colony-forming units.

We measured the effect of 6 standard (Adriamycin, BCNU, DTIC, melphalan, vinblastine, actinomycin D) and 3 Phase II agents (cis-platinum, vindesine, AMSA) on melanoma colony-forming units (CFU) in soft agar from biopsies of 50 patients with metastatic melanoma. Melanoma CFU demonstrated marked heterogeneity in chemosensitivity to these 9 drugs. Reduction in survival of CFU below 38% at one-tenth the pharmacologically achievable 1h concentration (our operational definition of chemosensitivity) was obtained in only 19% of 200 in vitro trials, and was usually the same whether or not patients had been exposed to prior chemotherapy, suggesting that melanoma CFU are inherently resistant to presently available chemotherapeutic drugs. The soft-agar assay was 86% accurate (25/29 cases) in identifying drugs to which the tumour was resistant in vivo, and 63% accurate (12/19 trials) in identifying drugs to which the tumour was clinically sensitive, counting mixed responses as responses. In contrast, if mixed responses were classified as progressive disease, the accuracy of identification of sensitivity fell to 42% (8/19 trials). These investigations furnish a quantitative description of the chemosensitivity of human metastatic melanoma CFU. Additionally, these studies serve as a useful step towards the development of an in vitro chemosensitivity test for human melanoma, and provide an operational quantitative basis for further exploration of in vitro-directed therapy in metastatic neoplasms