Hot spot identification method based on Andrews curves: an application on the COVID-19 crisis effects on caregiver distress in neurocognitive disorder.

Identifying and locating areas - hot spots - that present high concentration of observations in a high-dimensional data set is crucial in many data processing and analysis methods and techniques, since observations that belong to the same hot spot share information and behave in a similar way. A useful tool towards that aim is the reduction of the data dimensionality and the graphical representation of them. In the present paper, a new method to identify and locate hot spots is proposed, based on the Andrews curves. Simulations results demonstrate the performance of the proposed method, which is also applied to a high-dimensional data set, regarding caregiver distress related to symptoms of people with neurocognitive disorder and to the mental effects of the recent outbreak of the COVID-19 pandemic.

Robust inference under r-size-biased sampling without replacement from finite population.

The case of size-biased sampling of known order from a finite population without replacement is considered. The behavior of such a sampling scheme is studied with respect to the sampling fraction. Based on a simulation study, it is concluded that such a sample cannot be treated either as a random sample from the parent distribution or as a random sample from the corresponding r-size weighted distribution and as the sampling fraction increases, the biasness in the sample decreases resulting in a transition from an r-size-biased sample to a random sample. A modified version of a likelihood-free method is adopted for making statistical inference for the unknown population parameters, as well as for the size of the population when it is unknown. A simulation study, which takes under consideration the sampling fraction, demonstrates that the proposed method presents better and more robust behavior compared to the approaches, which treat the r-size-biased sample either as a random sample from the parent distribution or as a random sample from the corresponding r-size weighted distribution. Finally, a numerical example which motivates this study illustrates our results.

Methodology for improving reliability of river discharge measurements.

Programs to monitor water characteristics are undertaken to identify any possible water pollution of a river. To compute reliable water pollution loads, accurate river discharge and pollutant/tracer concentrations are required. When pollutants/tracers are measured with sufficient precision, the accuracy of river discharge measurements becomes the most critical parameter of the pollutant load computation, as well as the largest error source. The absence of permanent measuring equipment in many rivers is a common difficulty for the implementation of monitoring programs. Alternatively, quick measurement methods which are low in cost and reliability (e.g. floats) are often employed to get an estimate of river discharges, when there are budgetary and time restrictions. In this paper, an original technique, mainly for use in ungauged rivers, is proposed for correcting river discharge measurements which have low levels of accuracy; this in turn would correct pollutant concentrations. A nonlinear optimization problem is developed based on water volume and pollutant mass conservation principles for river balance nodes, taking into consideration non-measurable latent quantities. Parallel measurements of discharge and tracers for representative cross-sections of a river and its tributaries are required. The measurement conditions should refer to the steady-state hydraulic conditions usually prevailing in the flow under consideration. In order to test the reliability of the method, a virtual river example is built, defining the real values of water characteristics and generating measurement sets via Monte-Carlo simulations combining random and systematic errors. For more than 92% of the generated measurement sets, the proposed technique results in a successful and acceptable correction for the total of the measured cross-sections. Finally, the method is applied to a real river and the measurements are corrected successfully.

Graphical tests for the assumption of gamma and inverse Gaussian frailty distributions.

The common choices of frailty distribution in lifetime data models include the Gamma and Inverse Gaussian distributions. We present diagnostic plots for these distributions when frailty operates in a proportional hazards framework. Firstly, we present plots based on the form of the unconditional survival function when the baseline hazard is assumed to be Weibull. Secondly, we base a plot on a closure property that applies for any baseline hazard, namely, that the frailty distribution among survivors at time t has the same form as the original distribution, with the same shape parameter but different scale parameter. We estimate the shape parameter at different values of t and examine whether it is constant, that is, whether plotted values form a straight line parallel to the time axis. We provide simulation results assuming Weibull baseline hazard and an example to illustrate the methods.

Traumatic pseudoaneurysm of the lateral plantar artery in a child.

This is a report of a pseudoaneurysm of the lateral plantar artery presenting in a child 3 weeks after injury to the foot. To the best of our knowledge a similar case has not previously been reported.

Application of ternary complexes in pharmaceutical analysis. IV--Spectrophotometric determination of iron (II) in anti-anaemic formulations, using as chelating ligands in micellar medium three newly developed hydrazones.

The preparation, structural and physicochemical characterisation of three new hydrazones of isoniazid with 2,3-dihydroxy-,3,4-dihydroxy- and 2,3,4-tri-hydroxybenzaldehyde are described. The formation of binary chelates of iron(III) with these hydrazones and ternary complexes with the hydrazones and various surfactants were studied including the optimization of the experimental conditions. The new reagents were successfully used for the spectrophotometric determination of iron(II) in anti-anaemic formulations after its oxidation with hydrogen peroxide to iron(III). The statistical comparison of the results obtained with the new reagents and with the classical o-phenanthroline method is presented.

Spectrophotometric method for the determination of carbidopa using neotetrazolium chloride.

A new high-sensitive spectrophotometric method for the determination of microquantities of carbidopa is described. The method is based on the reduction of neotetrazolium chloride by carbidopa in an alkaline ethanolic medium. The formazan formed exhibits an absorption maximum at lambda = 507 nm, with an apparent molar absorptivity of epsilon = 6.63 x 10(4) M-1 cm-1 and a corresponding Sandell's sensitivity of 3.68 ng cm-2. Beer's law is obeyed over the range of 0.10-6.0 micrograms mL-1 while the optimum concentration range is 0.125-5.0 micrograms mL-1. The regression line equation was calculated as: A = 0.271C + 0.0023 with a correlation coefficient of 1.0000 (n = 28). The accuracy and the precision of the method were considered as very satisfactory. The results obtained from the determination of carbidopa using both the described procedure and the corresponding USP. XXII and BP 1988 clinical methods were statistically compared by means of Student's t-test as well as by the variance ratio F-test, and no significant difference was observed.

[Single mandibular complete dentures]. / Olike odontostoichia mono gia kato gnatho.

Single mandibular complete dentures suffer greater pressures as the basal seat area available is limited and the opposing arch consists more or less of natural teeth. The practical approach of such a case is described. Study casts mounted on a Hanau-H or Dentatus articulator help the dentist form a clear picture of the existing relationships and avoid underestimation of problems and preposterous restorative procedures. Reducing and reshaping upper natural teeth by grinding in order to equilibrate the occlusal scheme becomes unavoidable in such cases. So, the patient should be informed about it from the very beginning. Jaw relation records should be verified and be absolutely correct before setting the lower posterior teeth and performing any major reshaping of the remaining upper teeth. The existence of natural teeth does not usually permit succeeding a bilaterally equilibrated occlusion. So, the posterior teeth are usually set into a cusp-to-cusp relationship and a balancing ramp is properly formed behind the last molars bilaterally, so that a three-point contact is provided in all eccentric movements, if possible. The need of remounting the casts through new interocclusal records and before delivering the denture to the patients is explained in detail. As the acrylic base exhibits dimensional changes long after the insertion of the denture, this occlusal adjustment has to be repeated more than once frequently. If, in spite of these adjustments, the lower denture continues to give symptoms, then the use of some kind of resilient liner is recommended.

Hepatocellular carcinoma in a patient with precirrhotic primary biliary cirrhosis.

Hepatocellular carcinoma is generally associated with long-standing chronic liver disease of diverse etiology, most commonly HBsAg-positive chronic active hepatitis, hemochromatosis, or alcoholic liver disease. Patients with primary biliary cirrhosis have only rarely developed a subsequent hepatocellular carcinoma. We report such a patient, a 77-year-old woman with an early, precirrhotic stage of primary biliary cirrhosis who developed a hepatoma.

A cytohistological analysis of roots whose growth is affected by a 60-Hz electric field.

Roots of Pisum sativum were exposed for 48 h to 60-Hz electric fields of 430 V/m in an aqueous inorganic growth medium. The growth in length of the exposed roots was 44% of that for control roots. Root tips were analyzed for mitotic index and cell cycle duration. Mature, differentiated root sections from tissue produced after electrode energization were analyzed for cell lengths and number of files. The major reason for the observation that exposed roots are shorter than control roots is that cell elongation in the former is greatly diminished relative to controls.

Bond strength of bimaterial acrylic resin combinations.

While further research is necessary on the subject of the strength and nature of the bond between different types of acrylic resins, our study shows that specimens fabricated from heat-accelerated BPM showed considerably higher transverse strength values when compared with the various bimaterial combinations. From this, and from the fact that all bimaterial combinations broke at the joining interface, it can be inferred that none of the acrylic resin bimaterial combinations developed a true "chemical bond."