2,459 research outputs found

    Cloaking by coating: How effectively does a thin, stiff coating hide a soft substrate?

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    From human tissue to fruits, many soft materials are coated by a thin layer of a stiffer material. While the primary role of such a coating is often to protect the softer material, the thin, stiff coating also has an important effect on the mechanical behaviour of the composite material, making it appear significantly stiffer than the underlying material. We study this cloaking effect of a coating for the particular case of indentation tests, which measure the `firmness' of the composite solid: we use a combination of theory and experiment to characterize the firmness quantitatively. We find that the indenter size plays a key role in determining the effectiveness of cloaking: small indenters feel a mixture of the material properties of the coating and of the substrate, while large indenters sense largely the unadulterated substrate

    THE PRE-CUSP PHASE OF TORMAC IV AND V

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    An heuristic analysis of the pre-cusp phase of the present Tormac experiments has been carried out. The immediate goal has been to identify the requirements for producing a stabilized pinch in Tormac V qualitatively similar to that in Tormac IV. Concurrently, V has been modified to increase the pinch current and experimental investigation is underway. The experimental procedure is to introduce a toroidal magnetic field into the gas filled chamber. A toroidal electric field is then induced which ionizes the gas; the associated toroidal current simultaneously pinches the discharge. Uncertainty about the details of this process, in particular, about the amount of toroidal flux trapped within the pinch, has led to a one parameter theory. Speculation about the plasma heating mechanism and the subsequent interaction of pinch and cusp is left aside at this time. The chambers are basically rectangular in cross section; but, for simplicity, an equivalent radius is used. Although the experimental discharge probably evolves into a diffuse pinch, a cylindrical sheet pinch model is studied as a first step in understanding the qualitative features of the experiment. A simple Alfven scaling for instability time scales, appropriate for the previous weak pinch and considered in the design of the ringing frequency of the induction circuit is now supplemented by the sheet pinch model. If merited, a more quantitative numerical diffuse pinch model can be developed later. It should be pointed out that cusp confinement, the central problem of the Tormac program, is not addressed here. The goal is simply to identify the requirements for reproducing this particular phase of the Tormac IV experiment

    Ghajn Klieb, (Rabat, Malta)

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    Between October and December 1999 a team of local and foreign undergraduates from the University of Malta carried out a survey of the site at Ghajn Klieb outside Rabat. The exercise constituted the practical part of a unit on the Principles of Archaeological Surveying directed by Dr Nicholas Vella of the Department of Classics & Archaeology. For the survey the team was joined by Hanna Stager, a graduate of the same department, who also researched some of the references used in this article. Initial reconnaissance of the site was carried out on 15 October 1999 with Nathaniel Cutajar and Michelle B uhagiar, Curator and Assistant Curator respectively at the National Museum of Archaeology. The scatter of surface ceramics and the existence of previously known and unknown features revealed the extent and potential of the site. It was decided that the locality of Ghajn Klieb warranted systematic study that could be carried out in various stages, with the longterm aim being an assessment of human activity and cultural behaviour at the site. The Museums Department gave the go-ahead for this project, and permission to collect the surface ceramics was granted. This short report is intended to give an outline of the work undertaken to date. Emphasis is placed on the field methods adopted and on the presentation of what we believe to be worth talking about at this stage. An effort is here made by the senior author to unravel the collaborative nature of the exercise by lending weight to individual thoughts and interpretations that arose while work progressed in the field.peer-reviewe

    Non-spatial skills differ in the front and rear peri-personal space

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    In measuring behavioural and pupillary responses to auditory oddball stimuli delivered in the front and rear peri-personal space, we find that pupils dilate in response to rare stimuli, both target and distracters. Dilation in response to targets is stronger than the response to distracters, implying a task relevance effect on pupil responses. Crucially, pupil dilation in response to targets is also selectively modulated by the location of sound sources: stronger in the front than in the rear peri-personal space, in spite of matching behavioural performance. This supports the concept that even non-spatial skills, such as the ability to alert in response to behaviourally relevant events, are differentially engaged across subregions of the peri-personal space

    What is the impact of intraoperative microscope-integrated oct in ophthalmic surgery? Relevant applications and outcomes. a systematic review

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    Background: Optical coherence tomography (OCT) has recently been introduced in the operating theatre. The aim of this review is to present the actual role of microscope-integrated optical coherence tomography (MI-OCT) in ophthalmology. Method: A total of 314 studies were identified, following a literature search adhering to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. After full-text evaluation, 81 studies discussing MI-OCT applications in ophthalmology were included. Results: At present, three microscope-integrated optical coherence tomography systems are commercially available. MI-OCT can help anterior and posterior segment surgeons in the decision-making process, providing direct visualization of anatomic planes before and after surgical manoeuvres, assisting in complex cases, and detecting or confirming intraoperative complications. Applications range from corneal transplant to macular surgery, including cataract surgery, glaucoma surgery, paediatric examination, proliferative diabetic retinopathy surgery, and retinal detachment surgery. Conclusion: The use of MI-OCT in ophthalmic surgery is becoming increasingly prevalent and has been applied in almost all procedures. However, there are still limitations to be overcome and the technology involved remains difficult to access and use

    Socio-Demographic Characteristics and Sexual Behavioral Factors of Patients with Sexually Transmitted Infections Attending a Hospital in Southern Italy

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    Sexually transmitted infections (STIs) are a serious global health problem. In Italy, data describing the vulnerability to STIs of specific sexual minorities and the influence of sociodemographic and behavioral determinants are limited, as most infections are not subject to mandatory notification. This retrospective study describes the sociodemographic profile and main sexual behaviors of patients attending a hospital in Palermo (Sicily, Italy) from January 2018 to March 2019 as predictors of STI risk. Patients were divided in subgroups: men-who-have-sex-with-men (MSM), men-who-have-sex-with-women (MSW), bisexual men and females. Data were obtained through an anonymous questionnaire. Patients were tested for chlamydia, syphilis, Mycoplasma genitalium infection, genital herpes and HPV infection. A total of 294 subjects with STIs (male/female ratio about 2:1) were screened. Of the total sample, 79.6% of patients were Italian. MSM accounted for 34.3%, MSW for 29.6%, bisexual men for 5.8% and females for 30.3%. A total of 44.5% of patients had a high education level, 42.5% reported irregular use of condoms, 20.7% reported having had 5-10 partners in the six months prior to the visit and 32.9% were HIV-positive. HPV infection and syphilis were the most prevalent STIs. Conclusions: The most common profile of patients attending our clinic was that of an adult, Italian man with a high level of education, poor use of condoms and a high number of partners. MSM had the highest sex-behavior-related risk for STIs. In addition, our results suggest that all STD teams need to implement counselling topics and recommendations to share with patients, as well as tips on how to approach sexual health education/counselling, thereby promoting patient-centered approaches and educational programs

    Self-referent versus other-referent information processing in dysphoric, clinically depressed and remitted depressed subjects

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    Examined the processing of responses directed toward the self versus others by dysphoric, clinically depressed and remitted depressed Ss. In Exp 1, 30 dysphoric Ss found positive and negative responses toward the self equally informative. 30 nondysphoric Ss found positive responses toward the self more informative. When responses were directed toward others, dysphorics found positive responses more informative than negative responses, while nondysphorics found positive and negative responses directed toward others equally informative. Exp 2 replicated these results with 27 clinically depressed and 27 nondysphoric Ss, showing that remitted depressed Ss found positive responses more informative, regardless of direction to self or others. Results suggest that positive and negative constructs are differentially accessible for these groups

    Common Genetic Variation in GLP1R and Insulin Secretion in Response to Exogenous GLP-1 in Nondiabetic Subjects: A pilot study

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    OBJECTIVE: Glucagon-like peptide (GLP)-1 receptor is encoded by GLP1R. The effect of genetic variation at this locus on the response to GLP-1 is unknown. This study assessed the effect of GLP1R polymorphisms on insulin secretion in response to hyperglycemia and to infused GLP-1 in nondiabetic subjects. RESEARCH DESIGN AND METHODS: Eighty-eight healthy individuals (aged 26.3 +/- 0.6 years, fasting glucose 4.83 +/- 0.04 mmol/l) were studied using a hyperglycemic clamp. GLP-1 was infused for the last 2 h of the study (0.75 pmol/kg/min over 121-180 min, 1.5 pmol/kg/min over 181-240 min). beta-Cell responsivity (Phi(Total)) was measured using a C-peptide minimal model. The effect of 21 tag single nucleotide polymorphisms (SNPs) in GLP1R on Phi(Total) was examined. RESULTS: Two SNPs (rs6923761 and rs3765467) were nominally associated with altered beta-cell responsivity in response to GLP-1 infusion. CONCLUSIONS: Variation in GLP1R may alter insulin secretion in response to exogenous GLP-1. Future studies will determine whether such variation accounts for interindividual differences in response to GLP-1-based therapy
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