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PubMed2001

Non-gaussianity versus nonlinearity of cosmological perturbations.

Following the discovery of the cosmic microwave background, the hot big-bang model has become the standard cosmological model. In this theory, small primordial fluctuations are subsequently amplified by gravity to form the large-scale structure seen today. Different theories for unified models of particle physics, lead to different predictions for the statistical properties of the primordial fluctuations, that can be divided in two classes: gaussian and non-gaussian. Convincing evidence against or for gaussian initial conditions would rule out many scenarios and point us toward a physical theory for the origin of structures. The statistical distribution of cosmological perturbations, as we observe them, can deviate from the gaussian distribution in several different ways. Even if perturbations start off gaussian, nonlinear gravitational evolution can introduce non-gaussian features. Additionally, our knowledge of the Universe comes principally from the study of luminous material such as galaxies, but galaxies might not be faithful tracers of the underlying mass distribution. The relationship between fluctuations in the mass and in the galaxies distribution (bias), is often assumed to be local, but could well be nonlinear. Moreover, galaxy catalogues use the redshift as third spatial coordinate: the resulting redshift-space map of the galaxy distribution is nonlinearly distorted by peculiar velocities. Nonlinear gravitational evolution, biasing, and redshift-space distortion introduce non-gaussianity, even in an initially gaussian fluctuation field. I investigate the statistical tools that allow us, in principle, to disentangle the above different effects, and the observational datasets we require to do so in practice.

Journal Article↗
PubMed1991

[Effects of respiratory physical therapy and nasopharyngeal suction on gastroesophageal reflux in infants less than a year of age, with or without abnormal reflux].

The purpose of this study was to analyse the effects on gastro-oesophageal reflux (GOR) of the different manipulations used during pulmonary physical therapy (nasal suctions, oropharyngeal suctions, acceleration of expiratory flow). 115 children less than 1 year old, were divided into two groups according to the results of oesophageal pH monitoring: 44 with and 61 without pathological GOR. Nasal suctions did not significantly increase GOR in children without pathological GOR. Oropharyngeal suctions increased GOR significantly more than nasal suctions (*p = 0.031). The technique of acceleration of expiratory flow, used in 35 degrees verticalized position and supine position, increased the index of reflux and the time with oesophageal pH below 4 in children with pathological GOR. However it did not increase reflux in normal children. The index of induced reflux in the whole population was increased in the horizontal position (4.81 +/- 0.88 reflux/hour) as compared with 35 degrees verticalized (2.92 +/- 0.79 reflux/hour). These oesophageal pH measurements confirm the clinical observations often made during physical therapy (vomiting, regurgitations, reflex cough). This statistical study suggests that one should take into account the adverse factor of GOR secondary to pulmonary physical therapy. It seems better to use nasal rather than oropharyngeal suctions and also to use the acceleration of expiratory flow technique in the 35 degrees verticalized rather than in the supine position, even more so if a pathological reflux does exist.

Gastroesophageal Reflux↗
PubMed2004

Clinical predictors for differential diagnosis of acute scrotum.

Accurate and early diagnosis of acute scrotum is of the utmost importance to avoid testicular loss and/or needless surgery. The aim of this study is to analyze the clinical presentation and physical examination parameters together with the results of imaging studies in order to find out predictors for the differential diagnosis of acute scrotum with special emphasize on testicular torsion (TT). Patients who were treated for acute scrotum in our unit from 1970 up to and including 2000 were reviewed retrospectively. The study group was subdivided into three groups: "testicular torsion (TT)", "torsion of testicular appendage (TTA)", and "epididymoorchitis (EO)" group according to the diagnosis confirmed by radiologic and surgical findings. Presence and/or absence of various parameters related to clinical presentation, physical examination, and results of imaging studies were analyzed by statistical means in each group. One hundred and sixty children with a mean age of 12.2 years formed the study group. The mean duration of symptoms was 15 hours. No significant difference was noted between the three groups with regard to mean age and duration of symptoms. Nuclear scintigraphy and Doppler ultrasound were used as diagnostic aids in 50 and 66 children, respectively. Clinical presentation parameters including the presence of a) previous trauma, b) pain attacks, and c) nausea and vomiting, had the highest sensitivity, specificity, positive and negative predictive values in the TT group and the lowest values in the EO group. In contrast, the EO group had the highest statistical values with regard to presence of dysuria and micturition disorders. Physical examination parameters consisting of a) elevation, b) transverse location of testis, c) anterior rotation of epididymis, and d) absence of cremasteric reflex had the highest statistical values in the TT group. Contrary to this, imaging studies had the highest specificity and positive predictive values in the TTA group and the lowest values in the TT group. Previous history of trauma and pain attacks, presence of nausea and vomiting, and absence of urinary complaints are the main predictors of TT. Elevation and transverse location of testis with an anteriorly rotated epididymis associated with loss of ipsilateral cremasteric reflex strongly indicate TT. Although accuracy of imaging studies is higher for the differential diagnosis of TTA and EO, there is a considerable risk of misdiagnosis. Therefore, differential diagnosis of acute scrotum, particularly TT, still remains a clinical diagnosis, and clinical parameters deserve more importance in surgical decision making.

Adolescent↗
PubMedDate not supplied

Bronchopulmonary hygiene physical therapy in bronchiectasis and chronic obstructive pulmonary disease: a systematic review.

OBJECTIVES: This study had two objectives: (1) to examine the effects of bronchopulmonary hygiene physical therapy on patients with chronic obstructive pulmonary disease and bronchiectasis; (2) to determine any differences between manual and mechanical techniques for bronchopulmonary hygiene physical therapy. DESIGN: The study design was a systematic review of the literature that used an exhaustive search for trials and review methods prescribed by the Cochrane Collaboration. INCLUSION CRITERIA: Randomized controlled trials examined patient groups, interventions, and dependent variables. PATIENTS: Patients included those with chronic obstructive pulmonary diseases (emphysema or chronic bronchitis) or bronchiectasis. INTERVENTIONS: Any of the following interventions or combinations thereof were included: manual interventions, such as postural drainage, chest percussion, vibration, chest shaking, directed coughing, or forced exhalation technique. CONTROLS: Controls of the study were as follows: no intervention; placebo; coughing; and mechanical interventions, such as mechanical vibration. RESULTS: The search identified 99 potential trials; inclusion or exclusion analysis left 7, which examined a total of 126 patients. Mean score on trial quality was 1.4 (5 = greatest). Three separate trials (N = 51) found statistically significant effects for bronchopulmonary hygiene physical therapy on sputum production and radioaerosol clearance. No trials (N = 126) found statistically significant effects on pulmonary function variables or differences between manual and mechanical techniques. CONCLUSIONS: Considering the small sizes, low quality, and mixed results from the trials, the research on bronchopulmonary hygiene physical therapy is inconclusive. There is a need for adequately sized, high-quality, randomized controlled trials with uniform patient populations to examine the effects of bronchopulmonary hygiene physical therapy.

Breathing Exercises↗
PubMed1999

Reduced health-related quality of life among Hodgkin's disease survivors: a comparative study with general population norms.

BACKGROUND: Late complications after curative treatment of Hodgkin's disease are of special relevance because most of the cured are young adults. The aims of the present study were: (1) to compare health-related quality of life (HRQOL) in Hodgkin's disease (HD) survivors with normative data from the general Norwegian population and (2) to examine the relations between disease/treatment characteristics and HRQOL in the HD survivors. PATIENTS AND METHODS: 459 HD survivors aged 19-74 years (mean 44.0, SD 11.8) treated at the Norwegian Radium Hospital 1971-1991 were approached in 1994 and compared to norms from 2214 subjects approached in 1996. The norms are representative of the general Norwegian population. HRQOL was assessed by the Short Form 36 (SF-36), which measures HRQOL in eight separate scales (0 = worst health state, 100 = best health state). RESULTS: The HD survivors had lower scores than the normal controls on all scales after adjustment for age, gender and educational levels. Statistically significant differences (P < 0.01) were found in general health (10.4), physical functioning (6.1), role limitations (physical, 9.3), physical functioning (3.6) and in vitality (4.7). Patients with disease stage IB-IIB had the lowest scores on all scales. The differences in relation to stage/substage reached statistical significance (P < 0.01) in physical functioning and in role limitations (physical). Time since diagnosis, types of primary treatment or having relapsed were not associated with statistically significant differences in HRQOL. CONCLUSION: Long-term HD survivors have poorer HRQOL, primarily in physical health, than the general Norwegian population.

Adult↗
PubMed1991

Preoperative and postoperative voice analysis of uvulopalatopharyngoplasty patients.

While clinical studies almost universally report few speech and voice complications from uvulopalatopharyngoplasty, there is a paucity of prospective studies concerned with formal acoustic and perceptual evaluation of these patients. This study compares preoperative and postoperative recordings of 32 uvulopalatopharyngoplasty patients. Fast Fourier Transform analyses were made of both long-term spectra of a reading passage and the resonant characteristics of three vowels. Fundamental frequency and reading time were quantified. Polysomnographic studies of these patients were also compared. Finally, listener judgments of "better voice" were made on preoperative and postoperative pairs of the same patients performing a reading task. While the polysomnographic data demonstrated statistically significant improvement in the physical condition of the patients, no perceptual or acoustic measure of voice or speech was significant when preoperative and postoperative scores were compared.

Adolescent↗
PubMed2001

The motor dysfunction of patients with knee osteoarthritis in a Chinese population.

OBJECTIVE: To determine the extent of motor dysfunction in people with knee osteoarthritis (OA), as compared with similarly aged subjects without knee OA, in a Chinese population. METHODS: Seventy-six subjects participated in this study. Isometric peak torque of the knee muscles, range of knee motion at rest and during walking, gait velocity, cadence, and stride length were compared. RESULTS: The isometric peak torque of both the quadriceps and the hamstrings of the affected leg of patients with knee OA were weaker than those of the controls (most P < 0.05). The gait velocity was 23.4% slower (P = 0.001), the cadence 33.3% less (P < 0.001), and the stride length 13.4% shorter (P = 0.010) in the patients with OA. The range of knee motion in the patients was reduced by 11.2% at rest (P = 0.003) and by 14.7% during walking (P = 0.001). CONCLUSION: Patients with knee OA exhibited statistically significant deficiencies in the physical performance tested, as compared with similarly aged subjects without knee OA (by 9.6% to 33.3%), in a Chinese population. The indication that this study group seems less severely limited than those reported in Western literature warrants further investigation.

Aged↗
PubMed1995

The relationship between visual acuity and functioning and well-being among diabetics.

Given the enormous recent interest in functional capabilities related to vision, the goal of this study was to examine the relationship of standard clinical measures of vision (e.g. Snellen acuity) to functioning and well-being. The association between Snellen visual acuity, Amsler grid distortion and presence of diabetic retinopathy with self-reported functioning and well-being (SF-36) were examined in a sample of 327 diabetics from the Medical Outcomes Study (MOS). There was little or no correlation between Snellen visual acuity, Amsler grid distortion or diabetic retinopathy and functioning and well-being (i.e. SF-36 scales). Maximum product-moment correlation was 0.15 with worst eye visual acuity, 0.13 with best eye visual acuity, 0.08 with presence of retinopathy, and 0.10 with Amsler grid distortion. Analysis of variance revealed that visual acuity (both best and worst eye) was statistically related only to the physical function scale; no other exam measure was related to any other SF-36 scale score. Snellen visual acuity, Amsler distortion and diabetic retinopathy correlate weakly with patient self-reported functioning and well-being. Thus, the information provided by functioning and well-being measures is complementary to that of standard clinical measures of visual ability.

Activities of Daily Living↗
PubMed2002

Measuring recovery after a hip fracture using the SF-36 and Cummings scales.

The objective of this study was to assess outcomes of traditional treatment of fractures using the SF-36 and the Cummings Hip Scale. In designing randomized clinical trials, it is necessary to determine the timing of assessment either for progress or for the main outcome. We set out to document the recovery of patients after surgery for hip fracture using current standard methods of medical care. This was a prospective study of a cohort of patients. Patients who were receiving standard medical care completed the SF-36 and the Cummings Hip Scale at previously determined times postoperatively. The SF-36 has eight subscales, including assessments of physical function, physical role behaviors, bodily pain, mental health, social role, emotional role, vitality and general health. Thirty-eight patients completed the questionnaires at 1 year postoperatively as well as previous time points. On the Cummings Hip Scale and the physical function, bodily pain, mental health, social function, emotional role, vitality and general health subscales of the SF-36, recovery is near complete at 6 months. Only the physical role subscale differs, with a statistically significant difference between the values at 6 months and 1 year, (p = 0.02). Patients attained over 90% of the 1 year value by 6 months for all except the physical role subscale. The physical role subscale reached 85%. For a hip fracture patient who is on the road to recovery, the majority of the recovery has therefore taken place by 6 months.

Aged↗
PubMed1996

Relative friction minimization in fixed orthodontic bracket appliances.

The biomechanical and mathematical analysis of friction on an arch wire/bracket combination and the wire supports has demonstrated that there is an optimal relationship, i.e. minimal friction forces, between the bracket width and the distance between the adjacent brackets on the neighboring teeth. With this optimal situation, less force will develop for a given deflection of the arch wire. This, in turn, will lead to fewer frictional effects when the friction forces are assumed to be proportional to the concentrated perpendicular forces on the arch wire. As long as the contacting surface can be regarded as a point, Coulomb's law of friction can be applied in its simplest form. Relative friction minimization can thereby be qualitatively and quantitatively obtained by linear theory for any specified angulation, wire properties and coefficients of friction. Literature stating that narrow brackets will lead to less friction for specified angulation cannot be confirmed according to the presented analysis. The other extreme statement 'Use the widest bracket possible' also cannot be used in principle. Since the analysis shows a mathematical relationship between most of the relevant design variables of an arch wire/bracket combination and the magnitude of friction forces, empirical results can be sorted and ranked by their physical figures instead of by statistical distribution. In addition, it is possible to make recommendations about the appropriate bracket sizes for various cases. The dependences of the coefficients of friction themselves on material, surface roughness, lubrication, etc. are not investigated here. These factors are also very relevant, especially in reduction of the absolute magnitude of frictional forces, but this problem is left to tribologists.

Biomechanical Phenomena↗
PubMed1989

Preliminary implications of B-mode ultrasonography of the testicles of beef bulls with normal breeding soundness examinations.

Four polled Hereford bulls were found to have satisfactory breeding soundness examinations. They were examined by B-mode ultrasonography, at which time the testicular diameter was measured by ultrasound. The testicles were removed, measured physically and this data was compared with the ultrasound measurements and correlated with other parameters of the breeding soundness examination. The testicles from bulls with normal breeding soundness examinations appeared ultrasonographically identical with the normal testicles from other species such as the pig and dog. Results indicated that the bull testicle diameter could be accurately measured by ultrasonography. Neither ultrasonographic nor physical testicular diameter measurements correlated statistically with scrotal circumference, but they did correlated well with testicular circumference, weight and volume.

Journal Article↗
PubMed1989

Investigation of multiple simultaneously active brain sources in the electroencephalogram.

We present a method of investigating multiple simultaneously active brain sources that overlap both in space and time in the scalp electroencephalogram (EEG). In order to identify the contributions of the individual brain sources to measured potentials, we applied principal component analysis and various methods of rotating the principal components including a newly developed rotation procedure using frequency criteria. We related the results of these multivariate statistical techniques to a new physical model using multiple current dipoles with fixed anatomical locations and time-varying activities. We thus are able to study 3-dimensional location, time activity and interaction of multiple simultaneously active brain sources in the scalp EEG.

Brain↗
PubMed2006

Bone stress injuries of the talus in military recruits.

The purpose of the present study was to assess the incidence, anatomic distribution, and nature of fatigue bone stress injuries of the talus in military recruits based on magnetic resonance imaging (MRI). Military recruits referred to MRI examination due to exercise-induced ankle and/or foot pain were identified from the MRI archives. MR images of cases with bone stress injury findings in the talus were retrospectively re-evaluated concerning the anatomic location and type of the bone stress injury. During 96 months, fifty-one consecutive recruits displayed bone stress injuries of the talus in the population base of 117,149 person-years, yielding an incidence of 4.4 (3.2-5.5)/10,000 person-years. Bilateral injuries were seen in five of the patients. Of the 56 bone stress injuries, 40 occurred in the head, 15 in the body, and 5 in the posterior part of the talus. In four cases, both the head and the body were affected. Solitary, the talus was affected in 12 cases. In 44 cases, a stress injury was also present in other tarsal bones. Assessing the severity of the bone stress injury, a grade I-III injury was found in 46 and a grade IV injury with a fracture line in 10 of the cases. Injuries of the upper part of the body were associated with calcaneal stress injuries in 78% of the cases (P=0.03), and injuries of the head of the talus were associated with stress injuries in the naviculare in 60% of the cases (P=0.04). Age, sex, height, weight, body mass index, or physical fitness failed to reach statistical significance as risk factors for fatigue bone stress injuries of the talus. On MRI, the majority of the bone stress injuries of the talus were revealed in the head. A grade IV injury was discovered in 18% of the cases; in the remaining 82%, only grade I-III injuries were ascertained. In all locations, the lower grade bone stress injuries dominated. This study established the incidence of fatigue bone stress injury of the talus and indicated that these injuries are rare but not unseen in military recruits.

Adolescent↗
PubMed2005

Statistical modelling of fatigue-related electromyographic median frequency characteristics of back and hip muscles during a standardized isometric back extension test.

The purpose of the present study was to evaluate which statistical model - linear, logarithmic, quadratic or exponential - best described the fatigue-related electromyographic (EMG) changes of back and hip muscles. Twenty healthy volunteers performed a modified Biering-Sorensen test. The EMG activity of the latissimus dorsi (LD), longissimus thoracis pars thoracis (LTT) and lumborum (LTL), iliocostalis lumborum pars thoracis (ILT) and lumborum (ILL), multifidus (MF), gluteus maximus (GM) and biceps femoris (BF) was measured bilaterally using surface electrodes. Higher R(2) values were found for the quadratic models (p<0.05 for all muscles), and lower R(2) values for the logarithmic models (p<0.05 for LTT, LTL, ILL, MF and GM). The exponential models generated higher R(2) values compared to the linear ones for the LTT, LTL and MF (all p<0.05). Further analyses revealed, however, that these models did not add useful additional information, and therefore would only increase the complexity. The findings of the current study validate the use of simple linear regression techniques when studying fatigue-related EMG median frequency characteristics of back and hip muscles during isometric contractions.

Adult↗
PubMed2006

A comparison of cohesive strength and stiffness of Resilon and gutta-percha.

The purpose of this study was to compare the cohesive strength and stiffness of Resilon and gutta-percha under dry conditions and after 1 month of water storage to determine if they are stiff enough to reinforce roots. Dog-bone shaped specimens were created and pulled to failure at 3 mm/min in a Vitrodyne universal tester. The apparent modulus of elasticity, percent elongation, and yield stress were measured. Cohesive strength was defined as the yield stress. The data were analyzed using a two-way ANOVA for each outcome (alpha = 0.05). The results of this study show that the cohesive strength (that is the tensile stress when they begin to flow or break) and modulus of elasticity (or stiffness) of gutta-percha and Resilon are relatively low. Although the results showed statistically significant differences between the physical properties of gutta-percha and Resilon under varied conditions, these differences were not clinically significant. In conclusion, the stiffness of Resilon and gutta-percha is too low to reinforce roots after root canal therapy.

Analysis of Variance↗
PubMed2007

Quality of life for men receiving a second treatment for prostate cancer.

PURPOSE: We assessed the impact of second treatment on health related quality of life for men with prostate cancer. This issue is important because second treatment resulting from prostate specific antigen recurrence has the potential to further negatively impact health related quality of life and affect the overall value of treatment. We compared differences in health related quality of life before and after second treatment for men who had asymptomatic prostate specific antigen recurrence with those who did not have biochemical failure. MATERIALS AND METHODS: Men in this analysis (897) had localized disease, initially underwent radical prostatectomy monotherapy, and completed at least 1 health related quality of life questionnaire before and after radical prostatectomy. In this cohort 175 men underwent second treatment (nonadjuvant). The Medical Outcomes Survey Short Form-36 and UCLA Prostate Cancer Index were used to measure health related quality of life. Associations between patient groups and time on health related quality of life were analyzed using repeated measures. RESULTS: Men who received a second treatment presented with more severe disease before radical prostatectomy and had worse general health related quality of life. Although health related quality of life differed significantly with time for the 2 groups, most domains for the second treatment group improved or remained stable until 15 months before second treatment, at which point they declined. Scores in the sexual functioning and role-physical domains showed clinically and statistically significant patterns of decreasing with time. CONCLUSIONS: Health related quality of life is affected following second treatment but starts to decline approximately 1 year before second treatment. Not all aspects of health related quality of life decreased at the same rate, so patients should be counseled that certain domains may be affected more by additional treatment.

Aged↗