Newcomb-Benford law and the detection of frauds in international trade.

The contrast of fraud in international trade is a crucial task of modern economic regulations. We develop statistical tools for the detection of frauds in customs declarations that rely on the Newcomb-Benford law for significant digits. Our first contribution is to show the features, in the context of a European Union market, of the traders for which the law should hold in the absence of fraudulent data manipulation. Our results shed light on a relevant and debated question, since no general known theory can exactly predict validity of the law for genuine empirical data. We also provide approximations to the distribution of test statistics when the Newcomb-Benford law does not hold. These approximations open the door to the development of modified goodness-of-fit procedures with wide applicability and good inferential properties.

Cytological analysis of bronchoalveolar lavage fluid in asbestos-exposed workers.

BACKGROUND: Asbestos-related lung diseases are a group of heterogeneous disorders with different pathogenesis and prognosis. Very few studies investigated the BALF cell profile of asbestos exposed workers. The existence of a relationship between bronchoalveolar lavage fluid (BALF) cellular pattern and specific diagnosis and/or asbestos exposure biomarkers would allow the identification of effect biomarkers useful in the follow up of asbestos-exposed workers and in the diagnosis of asbestos-related diseases. OBJECTIVES: To assess BALF cell profile in formerly asbestos-exposed workers and its relationship with asbestos fibre (amphibole and chrysotile) and asbestos body (AB) concentrations. METHODS: 113 male workers formerly exposed to asbestos underwent bronchoscopy with bronchoalveolar lavage and were retrospectively enrolled. 35 of them were affected by pleural plaques and 10 were affected by asbestosis. Pulmonary functional tests (PFT), BALF cellular pattern, BALF mineralogical analysis with asbestos fibres and AB counting were performed in each patient. A statistical analysis with a multivariate linear regression model was adopted. RESULTS: From the statistical analysis of data a direct correlation between pack-years and BALF macrophages was found. Inversely correlation between pack-years and BALF lymphocytes was detected. There was not relationship among BALF cellular pattern, PFT values, specific diagnosis, BALF AB count or BALF asbestos fibre concentration. DISCUSSION: BALF cellular pattern does not seem to be related to asbestos exposure biomarkers like AB and asbestos fibre concentration in BALF. Instead, smoke habit can induce an increase in BALF macrophages and a decrease of BALF lymphocytes count.

Erythropoiesis, erythropoietin and blood lead levels.

In a previous study EPO values were significantly lower in exposed subjects (PbB > or =30 mcg/dl) than in controls (PbB" 20 mcg/dl). The aim of the study was to verify if high PbB cause the reduction of EPO in connection with the serum concentration of this hormone expected considering the Hct and hemoglobin (Hb) levels. Both in Pb exposed workers and controls blood levels of EPO, PbB, Hb, Hct were measured. It was not observed any line relation between Hct e log EPO (p = 0.01) and any multiple regression relation between log EPO, Hct and PbB into the total studied population. In our subjects PbB does not change physiologic relation between EPO and Hct and between EPO and Hb. Maybe because normal levels of Hct and Hb reduce EPO production in the healthy population. In physiologic condition of erythropoiesis, EPO does not seem influenced by PbB.

Arch replacement with collared elephant trunks: The Siena approach.

OBJECTIVE: To illustrate our experience and results in patients with diffuse aneurysmal disease treated with arch replacement using the Siena collared graft, a device designed in 2002 to improve the elephant trunk technique. Results of the first step surgical implant and the subsequent treatment strategies, with extensive use of endovascular techniques, are reported. METHODS: All aortic arch-replacement procedures using the Siena graft between February 2002 and January 2020 were retrospectively analyzed for early and late clinical outcomes. RESULTS: Of 146 patients (54 women, 36.9%) with a median age of 69.1 years (interquartile range 58.4-75.0 years), 55 (37.6%) had acute/chronic dissection with false lumen aneurysmal dilatation, 91 (62.3%) had degenerative aneurysms, 45 (30.8%) were redo operations, and 14 (9.5%) had connective tissue disease. First-stage outcomes: 10.9% 30-day mortality (n = 16); 5.4% stroke (n = 8, 6 disabling, 2 nondisabling; 3 fatal); and 0.6% paraplegia. Outcomes for 113 second-stage procedures (77.3%, n = 97 endovascular [66.4%], n = 16 surgical [10.9%]) were 5.3% and 8.8% 30-day and 180-day mortality; no stroke; 10.6% paraplegia. Median follow-up was 5.7 years (range: 0-18.02 years) median survival was 16.65 years (95% lower confidence limit, 10.06 years) with no significant difference between aneurysm and dissection patients. Freedom from further treatment was 87.0% (95% confidence interval, 79.9%-94.7%) at 5 years and 71.4% (95% confidence interval, 71.4%-84.7%) at 10 years; median time to reintervention was 2.59 years (interquartile range, 0.52-5.20 years) with no difference (P = .22) between dissection and aneurysm groups. CONCLUSIONS: Siena collared graft represents a reliable platform for the treatment of diffuse aneurysmal disease. This device offers the flexibility required in the treatment of extended aortic lesions and guarantees the choice of the most appropriate approach for treatment completion. In this context, the availability of hybrid grafts has not modified the role of this device in arch surgery.

On the agreement between bibliometrics and peer review: Evidence from the Italian research assessment exercises.

This paper analyzes the concordance between bibliometrics and peer review. It draws evidence from the data of two experiments of the Italian governmental agency for research evaluation. The experiments were performed by the agency for validating the adoption in the Italian research assessment exercises of a dual system of evaluation, where some outputs were evaluated by bibliometrics and others by peer review. The two experiments were based on stratified random samples of journal articles. Each article was scored by bibliometrics and by peer review. The degree of concordance between the two evaluations is then computed. The correct setting of the experiments is defined by developing the design-based estimation of the Cohen's kappa coefficient and some testing procedures for assessing the homogeneity of missing proportions between strata. The results of both experiments show that for each research areas of science, technology, engineering and mathematics the degree of agreement between bibliometrics and peer review is-at most-weak at an individual article level. Thus, the outcome of the experiments does not validate the use of the dual system of evaluation in the Italian research assessments. More in general, the very weak concordance indicates that metrics should not replace peer review at the level of individual article. Hence, the use of the dual system in a research assessment might worsen the quality of information compared to the adoption of peer review only or bibliometrics only.

Asbestos exposure biomarkers in the follow-up of asbestos-exposed workers.

Health surveillance of asbestos exposed workers should be stratified according to the exposure level. Unfortunately there is a lack of information regarding asbestos exposure in many working places and markers of asbestos exposure are often needed. The aim of the study was to assess the reliability of different dose and effect biomarkers in the follow up of asbestos-exposed workers. Mineralogical analysis of bronchoalveolar lavage fluid (BALF) as a biomarker of asbestos fibre burden was performed in a population of 307 male subjects occupationally exposed to asbestos. Using nonparametric statistical methods 8 variables were analyzed with respect to asbestos-related diseases and working sectors. The existence of a relationship between serum soluble mesothelin-related peptides (SMRP) and asbestos exposure levels was also investigated. Concentrations of amphiboles, chrysotile and asbestos bodies in BALF were higher in patients with asbestosis as well as in railway industry workers. A correlation between the onset of non malignant asbestos-related diseases and the levels of SMRP concentration was not found. This study confirms that fibre concentration in BALF may be considered as a reliable biomarker of previous asbestos exposure, whereas SMRP does not appear to be influenced by asbestos exposure levels.

Limited role of aortic size in the genesis of acute type A aortic dissection.

OBJECTIVE: Increased dimension of the aortic root and proximal aorta is considered a significant risk factor for catastrophic events that involve the ascending aorta. The objective of this study was to determine the possible correlation between pre-dissection aortic diameter and the occurrence of Stanford type A aortic dissection. METHODS: Samples of dissected ascending aortas were obtained from 220 patients at the time of their operation. Two groups were identified: patients with connective tissue disorders (Group 1, n=94) and those without (Group 2, n=126). Measurements of the true (intimal) lumen were conducted and extrapolated as reliable approximation of pre-dissection aortic diameter. The possible association of intimal diameter with anthropometric and demographic data was analyzed. RESULTS: Median aortic diameter was, respectively, 41.8 and 41.3mm for patients with and without connective tissue disorders (41.4mm for the entire cohort). Data analysis indicated that 57% of patients had aortic diameter above 40 mm, while patients with frank aneurysm accounted only for 10%; this proportion was higher in Group 1 compared to Group 2 (17.2% vs 4.7%). Poor or no correlation was demonstrated between aortic size and any of the anthropometric or demographic variables assayed. Significant subgroup differences were found among patients with a history of cigarette smoking, hypertension, diabetes, chronic renal insufficiency, and bicuspid aortic valve. CONCLUSION: Although aortic diameter remains a strong indication for preventive surgery in patients with inherited connective tissue disorders, acute aortic dissection occurs rarely in the setting of true ascending aortic aneurysms, and despite normal or near-normal aortic size in more than one-third of subjects. Dissection superimposing on small aortic diameters can be regarded as an expression of substantial functional tissue susceptibility to aortic catastrophic events.

Extrathoracic cannulation of the left common carotid artery in thoracic aorta operations through a left thoracotomy: preliminary experience in 26 patients.

BACKGROUND: In aortic operations performed through a left thoracotomy, which require total bypass and deep hypothermic circulatory arrest, femoral artery cannulation is commonly used for arterial perfusion. This route limits the time of safe circulatory arrest and is associated with the risks of retrograde embolization or, in the case of aortic dissection, malperfusion of the vital organs. To overcome these problems, we have used cannulation of the extrathoracic left common carotid artery to ensure a central a route of arterial perfusion in these operations. The preliminary results are presented. METHODS: Between December 1999 and April 2001, we used left common carotid artery cannulation in 26 operations on the thoracic aorta performed through a posterolateral thoracotomy with an open technique during deep hypothermic circulatory arrest. Institutional review board approval and informed consent were obtained. The indications included perforating atherosclerotic ulcer (n = 5), chronic aortic aneurysm (n = 9), acute type B aortic dissection (n = 3), and chronic dissection of the thoracic aorta (n = 9). Transcranial Doppler ultrasonographic monitoring of both the right and left middle cerebral arteries was used to assess the adequacy of cerebral bihemispheric perfusion and to determine the differences in blood flow velocities throughout the procedure. RESULTS: Left common carotid artery cannulation was successful in all patients. All patients awoke from the operation, and none had cerebrovascular accidents. None died in the hospital, and complications related to carotid artery cannulation were not observed. None of the patients experienced postoperative paraplegia. In all patients transcranial Doppler monitoring indicated the absence of cerebral embolic phenomena throughout the entire procedure. Significant differences in middle cerebral artery flow velocities were observed at different phases of the procedures and between the right and left middle cerebral arteries during carotid cannulation and during selective cerebral perfusion. Nevertheless, the maximal drop of right middle cerebral artery blood velocity during selective perfusion through the left common carotid artery was within 50% of the left middle cerebral artery velocity, indicating adequate bihemispheric perfusion. CONCLUSIONS: In patients undergoing aortic operations through a left thoracotomy, extrathoracic left common carotid artery cannulation was a safe and effective means of providing proximal arterial inflow during cardiopulmonary bypass, which can be used to selectively perfuse the brain, as well as to prevent embolic phenomena in the arch vessels.

Cerebral autoregulation after hypothermic circulatory arrest in operations on the aortic arch.

BACKGROUND: The purpose of this study was to determine whether patients who undergo thoracic aorta repairs with the aid of hypothermic circulatory arrest experience impairments in cerebral autoregulation, and to ascertain the influence of three different techniques of cerebral protection on autoregulatory function. METHODS: Sixty-seven patients undergoing elective aortic arch procedures with hypothermic circulatory arrest were tested for cerebral dynamic autoregulation using continuous transcranial Doppler velocity and blood pressure recordings. Twenty-three patients were treated using hypothermic circulatory arrest without adjuncts (group 1), 25 using antegrade cerebral perfusion (group 2), and 19 using retrograde cerebral perfusion (group 3). RESULTS: There were no hospital deaths. Two major strokes occurred in this series; 9 patients experienced temporary neurologic dysfunction: in all these patients severe impairment of cerebral autoregulation was observed. Cerebral autoregulation in the immediate postoperative period was preserved only in patients treated with antegrade cerebral perfusion. Severe impairments were observed in the other two groups in which the degree of autoregulatory response was inversely correlated to the duration of the cerebral protection time during hypothermic circulatory arrest. Postoperative improvement of autoregulatory function was observed in the majority of patients. Our data suggest the exposure to brain damage in the presence of autoregulation impairment, thus indicating that postoperative hypotensive phases may further contribute to neurologic impairment. CONCLUSIONS: The status of cerebral autoregulation in the postoperative period after hypothermic circulatory arrest procedures is profoundly altered. The degree of impairment is influenced by the cerebral protection technique. This study indicates the beneficial role of antegrade perfusion during hypothermic circulatory arrest for the preservation of this function and suggests that postoperative cerebral autoregulation impairment can be regarded as an expression of central nervous system injury.

Repeatability and agreement of 2 Scheimpflug analyzers in measuring the central corneal thickness and anterior chamber angle, volume, and depth.

PURPOSE: To evaluate the repeatability and agreement of 2 Scheimpflug tomographies (Pentacam HR, Oculus GmbH; Sirius, CSO Inc.) in measuring the central corneal thickness (CCT) and depth (ACD), volume (ACV), and angle (ACA) of the anterior chamber. METHODS: Three consecutive measurements were performed in one eye of each subject, with both instruments. The following were evaluated: CCT, ACD, ACV, and ACA. Repeatability was assessed by the Friedman test and agreement was assessed by 4 different Wilcoxon tests for paired data. RESULTS: The study enrolled 30 patients. With Sirius tomography the Friedman test p values for testing homogeneity across measurements was with respect to CCT 0.320, ACD 0.315, ACV 0.171, and ACA 0.020; and with Pentacam CCT 0.191, ACD 0.010, ACV 0.704, and ACA 0.150. The Wilcoxon test p values for testing the measurement homogeneity between the corneal tomography Sirius and Pentacam showed the following: ACD 0.000, ACD 0.000, ACV 0.853, and ACA 0.000. CONCLUSIONS: The measurements may be considered substantially stable for each corneal tomography and each variable, but the 2 corneal tomographies do not produce statistically equivalent measurements.

Ranked set sampling for replicated sampling designs.

In practical ecological sampling studies, a certain design (such as plot sampling or line-intercept sampling) is usually replicated more than once. For each replication, the Horvitz-Thompson estimation of the objective parameter is considered. Finally, an overall estimator is achieved by averaging the single Horvitz-Thompson estimators. Because the design replications are drawn independently and under the same conditions, the overall estimator is simply the sample mean of the Horvitz-Thompson estimators under simple random sampling. This procedure may be wisely improved by using ranked set sampling. Hence, we propose the replicated protocol under ranked set sampling, which gives rise to a more accurate estimation than the replicated protocol under simple random sampling.

Pulmonary embolism in very old patients.

BACKGROUND AND AIMS: Diagnosis of pulmonary embolism (PE) in the elderly remains difficult and is often late, although its incidence increases steadily with age. Since few studies have reported the clinical picture of this disease in very old patients, the aim of our study was to focus on clinical, instrumental and laboratory aspects in patients 75 years of age and over with suspected PE. METHODS: Symptoms, signs, risk factors for venous thromboembolic diseases, 12-lead electrocardiograms, B-mode echocardiograms, chest X-rays, leg compression venous ultrasonography, latex-assay quantitative D-dimer, and arterial blood gas analyses were collected for 96 elderly patients of 75 years and over (mean age 81.22 +/- 4.81) with suspected PE, admitted to our acute geriatric ward from 1997 to 2000. Patients were divided into two groups: 59 patients with PE (PE+) confirmed by pulmonary angiography, scintigraphic lung scan or necropsy, and 37 patients with normal lung scan or without PE at necropsy (PE-). RESULTS: Dyspnea and chest pain were the most common symptoms in both groups, but significantly more frequent in the PE+ group. Tachycardia, fever, cyanosis, and tachypnea were the most common objective signs in both groups; tachycardia and tachypnea were not significantly different between the two groups. Bed rest, venous insufficiency and leg deep vein thrombosis were the most common venous risk factors in PE+ and significantly different with respect to PE-. Sinus tachycardia, ST-T abnormalities and right bundle branch block were the most common electrocardiographic aspects in PE+; echocardiograms showed significantly more frequent acute involvement of right heart in PE+, whereas chest X-rays were rarely compatible with PE and did not reveal differences between the two groups. D-Dimer was significantly higher in PE+ but was below 500 ng/mL only in 25% of cases in PE-. More severe hypoxemla, oxy-hemoglobin hyposaturation and increased alveolar-arterial oxygen gradients were found at arterial blood gas analysis in PE+. CONCLUSIONS: Although many analyzed clinical, instrumental and laboratory aspects were significantly more frequent in the PE+ group, they were all non-specific and not conclusive for diagnosis of PE. Our retrospective study focus may add information about the picture and diagnostic difficulties of PE in very old patients.