A Higher-Order Analysis of Basic Linkages for Harmonic Motion Generation

1987 ◽  
Vol 109 (3) ◽  
pp. 301-307 ◽  
Author(s):  
K. Farhang ◽  
A. Midha ◽  
A. Bajaj
Keyword(s):  
Perturbation Technique ◽  
Motion Generation ◽  
Link Length ◽  
Small Motion ◽  
Harmonic Motion ◽  
Order Analysis ◽  
Modified Equations ◽  
Crank Angle ◽  
The Mean ◽  
Definition Of

In an earlier work, a perturbation technique was first presented to obtain approximate simple harmonic equations for describing the output motions of rudimentary linkages, i.e., a crank-rocker and a slider-crank, with relativley small input cranks. The technique involved consideration of a small motion excursion about a so-called “mean linkage configuration.” These equations were facilitated through truncation of the binomial series expansion of the output motions, expressed in terms of the input crank angle. Assuming a small crank to ground link length ratio, terms containing second or higher powers of this ratio were neglected. This paper retains terms containing higher powers in an effort to improve upon (i) the definition of the mean linkage configuration, and (ii) the harmonic motion content representation of the output motions. The improvements made due to the “modified” equations, relative to the “original” ones, are pictorially presented as being significant.

Analysis and Design of Basic Linkages for Harmonic Motion Generation

1985 ◽  
Vol 107 (4) ◽  
pp. 499-506 ◽  
Author(s):  
A. Midha ◽  
R. J. Cipra ◽  
K. Farhang
Keyword(s):  
Order Of Approximation ◽  
Motion Generation ◽  
Small Motion ◽  
Analysis And Design ◽  
Harmonic Motion ◽  
Simple Harmonic Motion ◽  
Transmission Angle ◽  
Unique Approach ◽  
Planar Linkages

This paper deals with basic planar linkages driven by relatively small cranks, and as a consequence generating approximate simple harmonic motion at the output members. A unique approach is presented to yield the kinematic equations, as exemplified by planar crank-rocker and offset slider-crank linkages. The method involves the presumption of a mean linkage configuration and a small motion excursion therefrom. Its validity is demonstrated by means of several error plots, generated for varying, nondimensional linkage parameters and a constant mean transmission angle. These plots also serve to illustrate the order of approximation involved for a particular combination of parameters. Finally, the synthesis of a crank-rocker linkage for a representative set of requirements is exemplified using the equations developed herein.

Comparison of Fluorine(18)-fluorodeoxyglucose and Gallium(68)-citrate PET/CT in patients with tuberculosis

2019 ◽  
Vol 58 (05) ◽  
pp. 371-378
Author(s):  
Alfred O. Ankrah ◽  
Ismaheel O. Lawal ◽  
Tebatso M.G. Boshomane ◽  
Hans C. Klein ◽  
Thomas Ebenhan ◽  
...  
Keyword(s):  
Tracer Uptake ◽  
Pet Ct ◽  
The Mean ◽  
18F Fdg ◽  
Definition Of ◽  
Gallium 68 ◽  
Attending Physician ◽  
Pet Scans ◽  
The Brain

Abstract 18F-FDG and 68Ga-citrate PET/CT have both been shown to be useful in the management of tuberculosis (TB). We compared the abnormal PET findings of 18F-FDG- and 68Ga-citrate-PET/CT in patients with TB. Methods Patients with TB on anti-TB therapy were included. Patients had a set of PET scans consisting of both 18F-FDG and 68Ga-citrate. Abnormal lesions were identified, and the two sets of scans were compared. The scan findings were correlated to the clinical data as provided by the attending physician. Results 46 PET/CT scans were performed in 18 patients, 11 (61 %) were female, and the mean age was 35.7 ± 13.5 years. Five patients also had both studies for follow-up reasons during the use of anti-TB therapy. Thirteen patients were co-infected with HIV. 18F-FDG detected more lesions than 68Ga-citrate (261 vs. 166, p < 0.0001). 68Ga-citrate showed a better definition of intracerebral lesions due to the absence of tracer uptake in the brain. The mean SUVmax was higher for 18F-FDG compared to 68Ga-citrate (5.73 vs. 3.01, p < 0.0001). We found a significant correlation between the SUVmax of lesions that were determined by both tracers (r = 0.4968, p < 0.0001). Conclusion Preliminary data shows 18F-FDG-PET detects more abnormal lesions in TB compared to 68Ga-citrate. However, 68Ga-citrate has better lesion definition in the brain and is therefore especially useful when intracranial TB is suspected.

scholarly journals The Sankara Nethralaya Tamil Nadu Essilor Myopia (STEM) Study—Defining a Threshold for Non-Cycloplegic Myopia Prevalence in Children

2021 ◽  
Vol 10 (6) ◽  
pp. 1215
Author(s):  
Aparna Gopalakrishnan ◽  
Jameel Rizwana Hussaindeen ◽  
Viswanathan Sivaraman ◽  
Meenakshi Swaminathan ◽  
Yee Ling Wong ◽  
...  
Keyword(s):  
Open Field ◽  
Tamil Nadu ◽  
Mean Difference ◽  
School Vision ◽  
Elite School ◽  
Prevalence Estimates ◽  
The Mean ◽  
Clinically Significant ◽  
Set Up ◽  
Definition Of

The aim of this study was to investigate the agreement between cycloplegic and non-cycloplegic autorefraction with an open-field auto refractor in a school vision screening set up, and to define a threshold for myopia that agrees with the standard cycloplegic refraction threshold. The study was conducted as part of the Sankara Nethralaya Tamil Nadu Essilor Myopia (STEM) study, which investigated the prevalence, incidence, and risk factors for myopia among children in South India. Children from two schools aged 5 to 15 years, with no ocular abnormalities and whose parents gave informed consent for cycloplegic refraction were included in the study. All the children underwent visual acuity assessment (Pocket Vision Screener, Elite school of Optometry, India), followed by non-cycloplegic and cycloplegic (1% tropicamide) open-field autorefraction (Grand Seiko, WAM-5500). A total of 387 children were included in the study, of whom 201 were boys. The mean (SD) age of the children was 12.2 (±2.1) years. Overall, the mean difference between cycloplegic and non-cycloplegic spherical equivalent (SE) open-field autorefraction measures was 0.34 D (limits of agreement (LOA), 1.06 D to −0.38 D). For myopes, the mean difference between cycloplegic and non-cycloplegic SE was 0.13 D (LOA, 0.63D to −0.36D). The prevalence of myopia was 12% (95% CI, 8% to 15%) using the threshold of cycloplegic SE ≤ −0.50 D, and was 14% (95% CI, 11% to 17%) with SE ≤ −0.50 D using non-cycloplegic refraction. When myopia was defined as SE of ≤−0.75 D under non-cycloplegic conditions, there was no difference between cycloplegic and non-cycloplegic open-field autorefraction prevalence estimates (12%; 95% CI, 8% to 15%; p = 1.00). Overall, non-cycloplegic refraction underestimates hyperopia and overestimates myopia; but for subjects with myopia, this difference is minimal and not clinically significant. A threshold of SE ≤ −0.75 D agrees well for the estimation of myopia prevalence among children when using non-cycloplegic refraction and is comparable with the standard definition of cycloplegic myopic refraction of SE ≤ −0.50 D.

Changes in the legal environment and enforcement of firearm transfer laws in Pennsylvania and Maryland

2018 ◽  
Vol 25 (Suppl 1) ◽  
pp. i2-i4 ◽  
Author(s):  
Cassandra K Crifasi ◽  
Molly Merrill-Francis ◽  
Daniel W Webster ◽  
Garen J Wintemute ◽  
Jon S Vernick
Keyword(s):  
Court Decision ◽  
Annual Number ◽  
Legal Environment ◽  
Background Check ◽  
The Mean ◽  
Definition Of

The effectiveness of laws depends on circumstances affecting their enforcement. To assess such circumstances for comprehensive background check (CBC) and straw purchase laws for firearm sales, we examined prosecutions for CBC and straw purchase violations in Pennsylvania and CBC violations in Maryland. We generated pre-post variables and conducted t-tests to assess differences in the mean number of prosecutions filed following changes to the legal environments. The annual number of prosecutions for straw purchase violations increased significantly in Pennsylvania following the passage of a law that strengthened penalties for these violations (difference in means = +1310.86, P=0.003). The annual number of prosecutions for CBC violations decreased significantly in Maryland following a court decision that narrowed the definition of a firearm transfer making enforcement more difficult (difference in means = −20.52, P=0.026). Our findings suggest enforcement is likely influenced by the penalties associated with violating these laws and the interpretation of the language of the laws.

Mean Diameters in Parallel-Flow and Counter-Flow Aerosol Systems

1976 ◽  
Vol 98 (2) ◽  
pp. 297-302 ◽  
Author(s):  
K. G. T. Hollands ◽  
K. C. Goel
Keyword(s):  
Mass Transfer ◽  
Continuous Phase ◽  
General Concept ◽  
Parallel Flow ◽  
General Definition ◽  
Single Pair ◽  
Counter Flow ◽  
Mean Diameter ◽  
The Mean ◽  
Definition Of

The general concept of the mean diameter of the disperse phase of an aerosol system, first introduced by Mugele and Evans in 1951, has proven to be a very useful one. In this concept, the proper mean diameter, xp,q, is characterized by a single pair of indices, p and q, which are dependent on the actual type of aerosol system under consideration. This paper re-examines the validity of this concept of mean diameter in heat and mass transfer aerosol systems. The concept is found to be applicable only under a very narrow range of conditions. Attention is then given to a more general definition of a mean diameter, applicable to aerosol heat or mass exchangers. Analyses of these devices shows that the more general mean diameter is a function of the capacity rate ratio, R, and effectiveness of the heat exchanger, ε. Solutions to the governing equations have permitted the mean diameter to be presented graphically as a function of these variables. These solutions are given for two types of particle size distributions, the Rosin-Rammler and the log-probability, and for both parallel-flow and counter-flow heat exchangers. The solutions are, however, restricted to cases where the resistance to heat or mass transfer lies exclusively in the continuous phase.

Synthesis of Planar, Compliant Four-Bar Mechanisms for Compliant-Segment Motion Generation

1999 ◽  
Vol 123 (4) ◽  
pp. 535-541 ◽  
Author(s):  
L. Saggere ◽  
S. Kota
Keyword(s):  
Compliant Mechanisms ◽  
Shape Change ◽  
Synthesis Method ◽  
Elastic Equilibrium ◽  
Body Motion ◽  
Motion Generation ◽  
Generation Task ◽  
Potential Applications ◽  
Flexible Segment ◽  
Definition Of

Compliant four-bar mechanisms treated in previous works consisted of at least one rigid moving link, and such mechanisms synthesized for motion generation tasks have always comprised a rigid coupler link, bearing with the conventional definition of motion generation for rigid-link mechanisms. This paper introduces a new task called compliant-segment motion generation where the coupler is a flexible segment and requires a prescribed shape change along with a rigid-body motion. The paper presents a systematic procedure for synthesis of single-loop compliant mechanisms with no moving rigid-links for compliant-segment motion generation task. Such compliant mechanisms have potential applications in adaptive structures. The synthesis method presented involves an atypical inverse elastica problem that is not reported in the literature. This inverse problem is solved by extending the loop-closure equation used in the synthesis of rigid-links to the flexible segments, and then combining it with elastic equilibrium equation in an optimization scheme. The method is illustrated by a numerical example.

scholarly journals Preceptors in Medical Residency Programs: Epidemiological Profile and Pedagogic Training

2020 ◽  
Vol 44 (4) ◽  
Author(s):  
Aderval de Melo Carvalho Filho ◽  
Almira Alves dos Santos ◽  
Rozangela Maria de Almeida Fernandes Wyszomirska ◽  
Isabella Costa Figueiredo Medeiros
Keyword(s):  
Health Care Professionals ◽  
The State ◽  
Public Institution ◽  
Medical Residency ◽  
Residency Programs ◽  
Service Training ◽  
The Mean ◽  
Definition Of ◽  
Epidemiological Profile ◽  
Mean Time

Abstract: Introduction: Medical Residency is a specialization course characterized as in-service training, considered in Brazil as the gold standard in the development of specialist physicians’ training. The medical residency preceptorship is an activity carried out by a specialist physician, responsible for monitoring resident physicians. However, there is neither a definition of the main requirements for such a preceptor, nor of his/her academic background to carry out the due teaching training, and it was possible to notice a relative lack of preparation regarding the pedagogical aspects. Methods: Descriptive study based on a quantitative approach, comprising 200 preceptors, of both genders, from medical residency programs in Maceió, state of Alagoas, Brazil. Results: The mean age was 43.31 ± 10.31 years, with a slight majority of female participants (52.5%). The mean time since graduation was 19.5 ± 10.58 years, and 83% of the participants had graduated in the state of Alagoas. Moreover, 78.5% said they had their Medical Residency certification, with an increased trend of public institution preceptors getting their degree at the stricto sensu level. The mean time of their completed postgraduate course was 12.63 ± 10.87 years and 7.07 ± 6.99 years being a preceptor. Only 19% mentioned they had some qualification for exercising the preceptorship, and 29.5% work as the teachers at the undergraduate level. The state of Alagoas has followed the expansion of the Residency programs, justifying the mean age found, similar to other studies. The majority of female participants can be associated with the feminization of health care professionals. The high percentage of preceptors with medical residency qualification is in accordance with Resolution n. 4/1978. We found experienced preceptors, but some authors differed. The low percentage of preceptors with qualification for exercising preceptorship indicates low interest and lack of available training. Conclusion: This study population is characterized as being young, and most are females. They have had long professional experience, and most have graduated in the state of Alagoas. There is a predominance of medical residency as their main qualification, and few of them have had training in the field. Finally, preceptors from public institutions have mostly got their degrees at the stricto sensu level.

scholarly journals The permanent tide and the International Height Reference Frame IHRF

2021 ◽  
Vol 95 (9) ◽  
Author(s):  
Jaakko Mäkinen
Keyword(s):  
Reference Frame ◽  
International Association ◽  
Reference Value ◽  
Equipotential Surface ◽  
Terrestrial Reference Frame ◽  
Reference Level ◽  
Consistent Estimate ◽  
The Mean ◽  
Global Mean Sea Level ◽  
Definition Of

AbstractThe International Height Reference System (IHRS), adopted by International Association of Geodesy (IAG) in its Resolution No. 1 at the XXVI General Assembly of the International Union of Geodesy and Geophysics (IUGG) in Prague in 2015, contains two novelties. Firstly, the mean-tide concept is adopted for handling the permanent tide. While many national height systems continue to apply the mean-tide concept, this was the first time that the IAG officially introduced it for a potential field quantity. Secondly, the reference level of the height system is defined by the equipotential surface where the geopotential has a conventional value W0 = 62,636,853.4 m2 s–2. This value was first determined empirically to provide a good approximation to the global mean sea level and then adopted as a reference value by convention. I analyse the tidal aspects of the reference level based on W0. By definition, W0 is independent of the tidal concept that was adopted for the equipotential surface, but for different concepts, different functions are involved in the W of the equation W = W0. I find that, in the empirical determination of the adopted estimate W0, the permanent tide is treated inconsistently. However, the consistent estimate from the same data rounds off to the same value. I discuss the tidal conventions and formulas for the International Height Reference Frame (IHRF) and the realisation of the IHRS. I propose a simplified definition of IHRF geopotential numbers that would make it possible to transform between the IHRF and zero-tide geopotential numbers using a simple datum-difference surface. Such a transformation would not be adequate if rigorous mean-tide formulas were imposed. The IHRF should adopt a conventional (best) estimate of the permanent tide-generating potential, such as that which is contained in the International Earth Rotation and Reference Systems Service Conventions, and use it as a basis for other conventional formulas. The tide-free coordinates of the International Terrestrial Reference Frame and tide-free Global Geopotential Models are central in the modelling of geopotential for the purposes of the IHRF. I present a set of correction formulas that can be used to move to the zero-tide model before, during, or after the processing, and finally to the mean-tide IHRF. To reduce the confusion around the multitude of tidal concepts, I propose that modelling should primarily be done using the zero-tide concept, with the mean-tide potential as an add-on. The widespread use of the expression “systems of permanent tide” may also have contributed to the confusion, as such “systems” do not have the properties that are generally associated with other “systems” in geodesy. Hence, this paper mostly uses “concept” instead of “system” when referring to the permanent tide.

Evaluation and validation of a patient completed psoriatic arthritis flare questionnaire

2021 ◽  
pp. jrheum.201317
Author(s):  
Philip S. Helliwell ◽  
William Tillett ◽  
Robin Waxman ◽  
Laura C. Coates ◽  
Mel Brooke ◽  
...  
Keyword(s):  
Psoriatic Arthritis ◽  
Disease Activity ◽  
Loss Of Function ◽  
Intra Class Correlation ◽  
The Mean ◽  
Definition Of ◽  
Multiple Domains ◽  
Intra Class Correlation Coefficient ◽  
Symptoms And Signs ◽  
Patient Opinion

Objective Evaluation of a psoriatic arthritis (PsA), multidimensional, patient completed disease flare questionnaire (FLARE). Methods The FLARE questionnaire was administered to 139 patients in a prospective observational study. The ‘gold standard’ of flare was based on patient opinion. Test-retest was evaluated by intra-class correlation coefficient (ICC). Disease activity was measured by the PASDAS, GRACE, CPDAI and DAPSA. Results The most common symptoms of a PsA flare were musculoskeletal, followed by fatigue, frustration, loss of function and an increase in cutaneous symptoms. The test-retest ICC for the FLARE questionnaire was 0.87 (95% CI 0.72 – 0.94). The optimum cut-off to identify a flare of disease was 4/10 (sensitivity 0.82, specificity 0.76; area under curve 0.85). For those patients scoring 4 or above, the mean score for the composite measures was as follows (score for those not reporting a flare in brackets): PASDAS, 5.3 ± 1.3 (3.1 ± 1.6); GRACE, 4.5 ± 1.2 (2.2 ± 1.4); CPDAI, 8.9 ± 2.5 (4.7 ± 3.1); DAPSA, 38.2 ± 20.3 (16.8 ± 14.9). In a new flare the increase in composite measure score was calculated as follows; 1 for PASDAS and GRACE, 2 for CPDAI, 7 for DAPSA. Moderate agreement was found between the definition of flare using the cut-off of 4, indicated by subjects in a separate question. Conclusion A PsA flare displays escalation of symptoms and signs across multiple domains; the FLARE questionnaire has external validity both in terms of composite disease activity and overall patient opinion of the state of their condition.

Abstract P254: Dementia and Use of Cardiac Catheterization and Angioplasty in Elderly ST-Elevation Myocardial Infarction Patients

2011 ◽  
Vol 4 (suppl_1) ◽  
Author(s):  
Marianne Ketterl ◽  
James A Mortimer ◽  
Elizabeth B Pathak
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Catheterization ◽  
Coronary Intervention ◽  
Admission Diagnosis ◽  
Percutaneous Coronary ◽  
Treatment Disparities ◽  
St Elevation ◽  
The Mean ◽  
Definition Of ◽  
To Receive

Introduction_ Percutaneous coronary intervention (PCI) is the first line of treatment for ST-elevated myocardial infarction (STEMI). Few studies addressed dementia as a barrier to receiving PCI. We evaluated disparities in the use of cardiac catheterization and PCI in STEMI patients with dementia. Methods_ A retrospective analysis was performed of Florida's comprehensive inpatient surveillance system for the years 2006-2007 with admission diagnosis of STEMI (ICD-9-CM codes 410.0 - 410.6, 410.8). Data were limited to patients ≥65 years admitted to hospitals with a high annual volume of PCIs (≥400), and transfer patients were excluded. We used a broad definition of dementia (ICD-9-CM codes 294.0, 294.1, 294.8, 294.9, 331.0-331.2, 331.7, 331.81, 331.82, 331.89, 331.9, 780.93, 780.97, 797). Logistic regression analysis was used to identify disparities in the use of cardiac catheterization and PCI among all STEMI patients, and in the use of PCI only among STEMI patients who received cardiac catheterization. Results_ A total of 8,310 STEMI patients who met our inclusion criteria were identified. Of these, 77.2% were catheterized and 67.1% received PCI. The mean age of the cohort was 76.3 years (SD 7.8 yrs); with 43.3% female; 83.4% white, 4.6% black, and 12% Hispanic/other. A total of 605 (7.3%) were demented. After adjustment for age, gender, and race/ethnicity, patients with dementia were less likely to be catheterized (RR 0.4, 95% CI 0.3-0.5), and less likely to receive PCI (RR 0.4, 95% CI 0.4-0.5) than non-demented patients. However, among patients who were catheterized, there was no difference in the use of PCI for demented vs. non-demented patients (p=0.32).Women were less likely to be catheterized than males (RR 0.7, 95% CI 0.7-0.8), but if catheterized, were more likely to receive PCI then men (RR 1.3, 95% CI 1.1-1.6). After adjustment for age, gender, and dementia, blacks were less likely to be catheterized (RR 0.5, 95% CI 0.4-0.6) and less likely to receive PCI (RR 0.6, 95% CI 0.5-0.7) than whites. Conclusions_ STEMI patients with dementia were much less likely to receive cardiac catheterization and consequently PCI. Our study confirms that treatment disparities exist for elderly demented patients after controlling for age, gender and ethnicity.

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