Measurement of Electron-Neutrino Charged-Current Cross Sections on

Using an 185-kg NaI[Tl] array, COHERENT has measured the inclusive electron-neutrino charged-current cross section on ^{127}I with pion decay-at-rest neutrinos produced by the Spallation Neutron Source at Oak Ridge National Laboratory. Iodine is one the heaviest targets for which low-energy (≤50 MeV) inelastic neutrino-nucleus processes have been measured, and this is the first measurement of its inclusive cross section. After a five-year detector exposure, COHERENT reports a flux-averaged cross section for electron neutrinos of 9.2_{-1.8}^{+2.1}×10^{-40} cm^{2}. This corresponds to a value that is ∼41% lower than predicted using the MARLEY event generator with a measured Gamow-Teller strength distribution. In addition, the observed visible spectrum from charged-current scattering on ^{127}I has been measured between 10 and 55 MeV, and the exclusive zero-neutron and one-or-more-neutron emission cross sections are measured to be 5.2_{-3.1}^{+3.4}×10^{-40} and 2.2_{-0.5}^{+0.4}×10^{-40} cm^{2}, respectively.

First Probe of Sub-GeV Dark Matter beyond the Cosmological Expectation with the COHERENT CsI Detector at the SNS.

The COHERENT Collaboration searched for scalar dark matter particles produced at the Spallation Neutron Source with masses between 1 and 220 MeV/c^{2} using a CsI[Na] scintillation detector sensitive to nuclear recoils above 9 keV_{nr}. No evidence for dark matter is found and we thus place limits on allowed parameter space. With this low-threshold detector, we are sensitive to coherent elastic scattering between dark matter and nuclei. The cross section for this process is orders of magnitude higher than for other processes historically used for accelerator-based direct-detection searches so that our small, 14.6 kg detector significantly improves on past constraints. At peak sensitivity, we reject the flux consistent with the cosmologically observed dark-matter concentration for all coupling constants α_{D}<0.64, assuming a scalar dark-matter particle. We also calculate the sensitivity of future COHERENT detectors to dark-matter signals which will ambitiously test multiple dark-matter spin scenarios.

Measurement of the Coherent Elastic Neutrino-Nucleus Scattering Cross Section on CsI by COHERENT.

We measured the cross section of coherent elastic neutrino-nucleus scattering (CEvNS) using a CsI[Na] scintillating crystal in a high flux of neutrinos produced at the Spallation Neutron Source at Oak Ridge National Laboratory. New data collected before detector decommissioning have more than doubled the dataset since the first observation of CEvNS, achieved with this detector. Systematic uncertainties have also been reduced with an updated quenching model, allowing for improved precision. With these analysis improvements, the COHERENT Collaboration determined the cross section to be (165_{-25}^{+30})×10^{-40} cm^{2}, consistent with the standard model, giving the most precise measurement of CEvNS yet. The timing structure of the neutrino beam has been exploited to compare the CEvNS cross section from scattering of different neutrino flavors. This result places leading constraints on neutrino nonstandard interactions while testing lepton flavor universality and measures the weak mixing angle as sin^{2}θ_{W}=0.220_{-0.026}^{+0.028} at Q^{2}≈(50 MeV)^{2}.

First Measurement of Coherent Elastic Neutrino-Nucleus Scattering on Argon.

We report the first measurement of coherent elastic neutrino-nucleus scattering (CEvNS) on argon using a liquid argon detector at the Oak Ridge National Laboratory Spallation Neutron Source. Two independent analyses prefer CEvNS over the background-only null hypothesis with greater than 3σ significance. The measured cross section, averaged over the incident neutrino flux, is (2.2±0.7)×10^{-39} cm^{2}-consistent with the standard model prediction. The neutron-number dependence of this result, together with that from our previous measurement on CsI, confirms the existence of the CEvNS process and provides improved constraints on nonstandard neutrino interactions.

Observation of coherent elastic neutrino-nucleus scattering.

The coherent elastic scattering of neutrinos off nuclei has eluded detection for four decades, even though its predicted cross section is by far the largest of all low-energy neutrino couplings. This mode of interaction offers new opportunities to study neutrino properties and leads to a miniaturization of detector size, with potential technological applications. We observed this process at a 6.7σ confidence level, using a low-background, 14.6-kilogram CsI[Na] scintillator exposed to the neutrino emissions from the Spallation Neutron Source at Oak Ridge National Laboratory. Characteristic signatures in energy and time, predicted by the standard model for this process, were observed in high signal-to-background conditions. Improved constraints on nonstandard neutrino interactions with quarks are derived from this initial data set.

An assessment of juvenile Atlantic cod Gadus morhua distribution and growth using diver operated stereo-video surveys.

Stereo-video scuba transects were conducted during daylight hours from June to September 2013 within a proposed marine protected area (MPA) in the Firth of Clyde, west of Scotland. More juvenile Atlantic cod Gadus morhua of fork length (LF ) range 6-11 cm were observed in substrata containing mixed gravel, including maerl, than in boulder-cobble substrata with high algal cover, or sand with low density seagrass. Community composition was significantly different between substratum types. A decrease in G. morhua abundance was observed over the period of data collection. Over time, mean and variance in G. morhua LF increased, indicating multiple recruitment events. Protecting mixed gravel substrata could be a beneficial management measure to support the survival and recruitment of juvenile G. morhua; other substrata might be important at night given their diel migratory behaviour. Stereo-video cameras provide a useful non-destructive fisheries-independent method to monitor species abundance and length measurements.

Changes in species diversity and size composition in the Firth of Clyde demersal fish community (1927-2009).

Following the repeal in 1962 of a long-standing ban on trawling, yields of demersal fish from the Firth of Clyde, southwest Scotland, increased to a maximum in 1973 and then declined until the directed fishery effectively ceased in the early 2000s. Since then, the only landings of demersal fish from the Firth have been by-catch in the Norway lobster fishery. We analysed changes in biomass density, species diversity and length structure of the demersal fish community between 1927 and 2009 from scientific trawl surveys, and related these to the fishery harvesting rate. As yields collapsed, the community transformed from a state in which biomass was distributed across numerous species (high species evenness) and large maximum length taxa were common, to one in which 90 per cent of the biomass was vested in one species (whiting), and both large individuals and large maximum length species were rare. Species evenness recovered quickly once the directed fishery ceased, but 10 years later, the community was still deficient in large individuals. The changes partly reflected events at a larger regional scale but were more extreme. The lag in response with respect to fishing has implications for attempts at managing a restoration of the ecosystem.

Contribution of the cheeks to the intraoral manipulation of food.

The role of the teeth in chewing has been studied extensively; however, less attention has been paid to soft tissue function. In this study the process of mixing within the bolus and the contribution of the cheeks to this process were investigated using a test food constructed from two differently colored chewing gums. A cheek guard was placed into either the left the or right buccal sulcus. Eighteen dentate subjects were instructed to chew four samples of gum for 30 strokes, two samples with the cheek guard in place and two without. Upon completion, the gum was removed from the mouth and its length was measured. The bolus was then placed into a plastic bag and flattened. Pairs of flattened samples chewed with and without the cheek guard in place were then assessed by five judges who were asked to identify which of each pair was most mixed. Inhibition of the cheek during chewing resulted in significantly longer samples, which were also less mixed.

Validation of communication between elderly denture wearers and dentists: a questionnaire on satisfaction with complete dentures using semi-structured interviews.

OBJECTIVES: To validate a semi-structured interview (SSI) for communication between complete denture wearers and dentists. DESIGN: A SSI using a questionnaire with eight questions on satisfaction with complete dentures (CD): covering function, aesthetics and comfort. The first seven questions used a five-point Likert scale and the last was dichotomous. Two dentists, carefully trained in the use of the structured questionnaire, administered the SSI. SETTING: A Greek Department of Prosthetic Dentistry. SUBJECTS: A consecutive sample of 78 CD wearers took part in the study. All subjects presented with complaints from their dentures. INTERVENTION: All participants and their dentures underwent clinical examination. RESULTS: The method showed good reliability, verified by the Cronbach alpha (0.86). Both dentists used the questionnaire produced very similar results. (Wilcoxon test 61-99%). Further, the association of the answers with respect to the five-point Likert scale was very high; all gamma coefficients were statistically significant except for pain and discomfort from the upper CD (CDU). CONCLUSIONS: This method of communication between patients and dentists is reliable and can be used to give good repeatability for qualitatively assessing satisfaction with CD. It can be valuable for clinical use and for extending the study of denture quality to establish outcome measures based on the subjective criteria of satisfaction.

The development of a method for functional assessment of dentures.

AIMS: To design and validate a method of assessing complete dentures from a functional standpoint. SUBJECTS: A random sample of 40 complete denture wearers took part in the study. SETTING: A university clinical department of prosthetic dentistry. INTERVENTION: We undertook a pilot study to refine the protocol and criteria. All participants and their dentures were examined by two authors independently, with no prior knowledge of the patients' complaints. DESIGN: We defined nine clinical factors of functional quality and applied criteria with binary scoring. We analysed the scores for these factors for inter-rater reliability. RESULTS: The method proved simple to apply and took less than 5 minutes to complete. The inter-examiner agreement for all factors was 86% to 100% giving Kappa scores of 0.64 to 1.00 (all Good or Very Good). CONCLUSIONS: This study successfully demonstrates that the technique, which we call the Functional Assessment of Dentures (FAD), can give good inter-examiner reliability. It can therefore be used separately as a routine diagnostic tool and to investigate the relationship between denture qualities and functional 'outcome' such as difficulty eating or dietary selection.

Validation of indices for functional assessment of dentures.

AIMS: To validate an assessment of qualities of complete dentures that may relate to functional success. SUBJECTS: A consecutive sample of 131 complete denture wearers took part in the study. SETTING: a Greek department of prosthetic dentistry. INTERVENTION: All participants and their dentures underwent clinical examination. DESIGN: The Functional Assessment of Dentures (FAD) 10-item criteria' describing clinical factors of denture quality was used. The rationale for selecting these particular criteria was to include a range of clinical factors to produce an overall assessment of complete dentures. The 10-item scale was examined for Internal Consistency and Construct Validity providing a summated rating scale whose total score could be used as an index for the quality of dentures. RESULTS: Both intra- and inter-examiner agreement for all 10 dichotomous scale criteria were all good or very good; the intra-examiner Kappa values were 0.72 to 0.91 and the inter- examiner values were 0.72 to 0.99. Statistical analysis revealed that a 7-item summated rating scale could be constructed which has marginally better internal consistency (reliability) and Construct Validity with fewer questions. CONCLUSIONS: The FAD criteria' can be used to give good repeatability. The adjustments made to the original summation scale, if confirmed by new studies, would further increase the practical utility of a FAD index for general dentists. In due course with data from future studies, discrimination on weighting of items will be appropriate to relate the impact of denture quality on quality of life.

Maximum bite force after the replacement of complete dentures.

OBJECTIVE: The aim of the present study was to investigate whether the maximum bite force (MBF) can be improved by the replacement of complete dentures for elderly people. DESIGN: Nine edentulous volunteers, mean age 74.2 (+/- 5.5) years and average denture experience 19.4 +/- 19.5 years (1 to 50 years) had replacement dentures made. After a rehearsal session, MBF was recorded with the old dentures, and with the new dentures immediately at insertion, at 3, 8 days, 2-3 weeks, 1, 2, 3 and 6-10 months post insertion (p-i.). MBF was recorded with the central bearing point method using a full-bridge strain gauge load cell. Data were analysed off-line using the mean of two peak readings per patient per session. RESULTS: The results indicate that MBF tended to be impaired when replacement dentures were first fitted (n.s.). However, this trend reversed during the first month p-i. for patients with a "moderate" lower ridge resorption of Atwood grade 3 or 4 (n = 5). Patients with more severe lower ridge resorption Atwood grade 5 or 6 (n = 4) showed a significantly lower MBF over the entire observation period (p < or = 0.05) and took longer to regain bite strength. Only patients with moderate bone resorption exceeded their pre-insertion level of MBF within the observation period of 6-10 months p-i. CONCLUSION: The present pilot study suggests that, at least for elderly patients with severe bone resorption, delayed improvement of MBF should be expected with replacement complete dentures.

The development of a simple objective test of mastication suitable for older people, using chewing gums.

AIMS: To develop and assess a simple test for evaluating the mastication of visco-elastic foods and prosthodontic success subsequent to treatment of older people. METHOD: The weight lost from chewing gum during mastication tests and the saliva secreted is weighed. The percentage of the original gum weight that is chewed out in a defined number of strokes is termed the Masticatory Effectiveness (ME) MATERIAL: Five edentate and three dentate volunteers were selected to provide a range of dental states and age. Four commercially available chewing gums of different origins and perceived hardness were tested, one without sweetener acted as a control for salivary stimulation. INTERVENTION: Pre-weighed samples of each gum were chewed, each for defined numbers of strokes. The saliva secreted was collected and weighed. The chewed gum was desiccated and the total weight loss of sweeteners chewed out provided an objective measure of chewing performance. RESULTS: Weight loss showed large differences between gums, between subjects and the number of strokes. ME was significantly correlated with salivary secretion rates for two subjects. The interaction between subject and gum was statistically significant, established by an ANOVA model, the value of which is shown for multivariate studies. Differential success between gums of different thickness may provide evaluation of denture stability. CONCLUSIONS: Measuring the weight lost from gums during chewing provides a simple test of masticatory effectiveness of visco-elastic foods. This has particular value both in functional assessment of older people and in physiological research.

Bolus dimensions in normal chewing.

Samples of 17 different types of chewing gum weighing between 0.3 and 22 g were presented to eight subjects. After chewing the samples for between 20 and 100 strokes the boluses of gum were removed from the mouth and their length was measured. Bolus length increased with weight from 0.3 to 4 g, but remained constant between 4 and 18 g at which point it began to increase once more. The range of sizes associated with this plateau is similar to the range of sizes of natural bites with other foods.

Food choice by older people: the use of semi-structured interviews with open and closed questions.

OBJECTIVE: To evaluate difficulty chewing, consequent food choice and impacts using both open and closed questions within a semi-structured interview format. DESIGN: A cross-sectional study using a semi-structured interview (SSI) with open and closed questions. SETTING: Independently living people in South-West London interviewed in their own homes. SUBJECTS: A group of 54, edentate people (mean age 82, R = 60-93 years) were studied. RESULTS: Most subjects (69%) expressed difficulty eating at least one type of food, half were unwilling to eat the foods they found difficult, others were conscious of cooking longer or cutting smaller in order to manage these foods, although no one accepted that they overcooked food. There were dramatic differences in the number of subjects expressing difficulty to chew various foods when responding to open and closed questions. Roast beef proved a good discriminator in this group of predominantly English subjects. The importance of the questioning process was also shown by the discrepancy of responses between variously prepared apples and the inability of any subjects to bite an unpeeled apple. CONCLUSIONS: For sensitive appraisal of food choice it is obviously essential to assess relevant foods, for the culture of the group being studied. Open questions provide a way of exploring which are the appropriate foods and food preparation as criteria to assess perceived chewing ability and treatment benefit. The semi-structured interview method is particularly valuable for the study of older people. Closed questions provide different information which is also necessary to secure recall by older people.

Simplified method of estimating masticatory performance.

Methods which measure masticatory performance include gravimetric, volumetric and direct observation which depend on the weight, volume and size, respectively, of a test food once chewing is completed. Almonds, one of the most common test foods used, have a convenient size and texture. However, due to their oily content and mixing with saliva, washing and drying is required to overcome the clumping of chewed particles. A method has been developed using bagged almonds to exclude saliva and preventing loss of almond particles in the mouth. In addition, microwaving the whole almond reduces the oil content of the almond, reducing clumping, and potentially eliminating the need for washing and drying the particles. A dentate volunteer was asked to chew seven blanched almonds and seven microwaved almonds. The chewed particles were separated using two sieves, weighed and optically scanned to measure the number and area of the particles. Results were obtained both before and after washing and drying of the chewed particles. The overall results for the test of masticatory performance is very similar whether or not a washing stage is used for microwaved almonds. For untreated almonds washing has a more noticeable effect and may still be considered necessary.

The effect of variation of the lingual shape of mandibular complete dentures on lingual resistance to lifting forces.

UNLABELLED: Increasing life expectancy, age related reduction in adaptability and progressive severe mandibular resorption all add to the importance of any factor improving the prosthetic success. OBJECTIVE: To investigate the effect of two different lingual shapes of lower dentures on patients' ability to resist lifting forces. DESIGN: Tongue pressures on the lingual surface of complete mandibular experimental dentures were recorded from mid-line, premolar and molar transducers. Two experimental prostheses were fabricated for each subject: one conventionally contoured, the other formed by piezography. SETTING: A clinical research laboratory. SUBJECTS: Five experienced complete denture wearers between age 64 and 82 years. INTERVENTION: Lifting forces were applied at the midline, left and right premolar sites in random order. MAIN OUTCOME MEASURES: Peak resistance to lifting forces and lingual pressures used during these tests. RESULTS: Lingual pressures exerted anteriorly were dramatically higher than those on premolar and molar surfaces. Significantly higher pressures were used to resist lifting forces applied to piezographically than conventionally formed contours; correspondingly, significantly higher lifting peak forces were, on average, resisted. CONCLUSIONS: Providing a lower denture with a piezographically produced lingual surface was shown, in this preliminary study, to enhance tongue retentive ability over a conventional design. It seems reasonable to maximise retentive potential with oblique sublingual polished surfaces and minimise the adaptive demand, particularly for older patients, by using a piezographic technique which "customises" the contour and precludes over-extension.

Chewing performance and occlusal contact area with the shortened dental arch.

The aim of this study was to investigate the effect of the loss of posterior teeth on the effectiveness of mastication. To evaluate this, chewing performance and occlusal contact area were investigated in 10 edentate subjects having implants stabilising a mandibular overdenture. A copy of the original lower denture was made for each subject, with removable teeth, which could be separated to convert a complete dental arch to a shortened dental arch, an extremely shortened dental arch, or a broken dental arch. Both post canine occlusal contact area and chewing performance demonstrated significant differences between the different arches. It was concluded that chewing performance is reduced by removing posterior teeth from implant stabilised mandibular complete dentures.

Prosthodontic treatment, patient response, and the need for maintenance of complete implant-supported overdentures: an appraisal of 5 years of prospective study.

The prosthodontic methods and outcomes of treating 127 patients in nine centres over a period of 5 years is described. The benefits perceived by patients and the changes induced in the denture-bearing tissues and temporomandibular joints are reported. To sustain effective treatment outcomes, the levels of maintenance needed by the overdentures are contrasted for restoration of the edentulous mandibles and maxillae.

Clinical and microbiological effects of topical minocycline in the treatment of elderly patients with periodontitis.

OBJECTIVE: To evaluate a 2% w/w minocycline gel (Dentomycin) in the treatment of older adults with chronic periodontitis. DESIGN: Vehicle-controlled, split-mouth SETTING: Dental Institute, St Bartholomew's and the Royal London School of Medicine and Dentistry. SUBJECTS: 22 adults (mean age 60 years). INTERVENTIONS: At baseline, patients received scaling and root planing. Test and placebo were applied at contralateral disease sites surrounding 22 test and 22 control teeth at baseline, and at weeks 2 and 4. MAIN OUTCOME MEASURE: Probing pocket depth, bleeding on probing and supragingival plaque measurements, and microbiological sampling, at one pocket site per tooth were undertaken at baseline, and at weeks 2, 4, 6 and 16. RESULTS: Microbial counts of Porphyromonas gingivalis, Prevotella intermedia and Eikenella corrodens did not change significantly over 16 weeks. No significant reductions in bleeding on probing and supragingival plaque score occurred with either gel. A larger reduction in mean pocket depth, from baseline to week 16, was found at test (6.50 to 4.95 mm; 24% reduction; P < 0.01) than at control sites (6.41 to 5.53 mm; 14% reduction; P < 0.05). CONCLUSIONS: Minocycline gel administration is a useful adjunct to scaling and root planing in the treatment of older adults with periodontitis.