566 research outputs found

    Kernel Weighted Smoothed Maximum Score Estimation for Applied Work

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    The endogenous binary response model frequently arises in economic applications when a covariate is correlated with the error term in the latent equation due to data limitations. Applied workers generally address endogeneity using the principle of Maximum Likelihood (ML) which imposes stringent paramet- ric assumptions. These ML estimators are inconsistent if the posited parametrization is incorrect which can translate in practice into aberrant results contradicting economic theory. Semiparametric estima- tors have been developed imposing weaker distributional assumptions. Some semiparametric techniques permit inferences from data but restrict heteroscedasticity which may furnish deceptive results. Other semiparametric techniques can accommodate almost any heteroscedasticity but forbid inferences. This article summarizes two new estimation techniques which allow for inferences under general heteroscedas- ticity conditions. Some Monte Carlo experiments are conducted highlighting the robust advantage of these estimators. Finally, these estimation techniques are applied to assess the eect of education on maternal pregnancy smoking using the 1988 National Health Interview Survey.

    Two Stage Semi Parametric Quantile Regression

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    We propose a root n consistent estimator for B0 when the qth conditional quantile of Y given X=x and Z=z takes the semi linear form g(x)+z'B0 where g(.) is an un- known real valued function,B0 a finite dimensional parameter and (X,Z) a couple of explanatory variables. Importantly, our estimator attains,under homoscedasticity,the semi parametric efficiency bound. This estimation is conducted in two steps. First, a Robinson's like demeaning of the original model is employed which provides a new quantile regression whose nuisance terms are estimated via a non parametric proce- dure.In the second stage, a quantile regression is conducted by smoothing the check function. We show that the previous estimator belongs to a class of estimators we propose to name "two stage semi parametric quantile".

    Метафора в публицистике: репрезентация вариантов языковой картины мира

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    Метафора как универсальное средство концептуализации действительности в том или ином виде свойственна всем языковым картинам мира независимо от национально-культурной принадлежности. В статье рассматриваются особенности политических метафор, включённых в публицистическую картину мира, которая является разновидностью языковой картины мира и представляет часть концептуальной картины мир

    The role of the Swiss list of occupational diseases in the protection of workers' health.

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    Occupational disease lists (ODLs) are essential legal mechanisms for recognising pathologies related to exposure to occupational hazards. In 2017, Switzerland revised its ODL and solicited stakeholders to review the ODL proposal. This revision represented an important and rare event, and was an opportunity to assess the legal status and role of Swiss ODL. In this research, we examined the structure and content of this revised Swiss list, by comparing it to other official recommendations and ODLs, including those of the International Labour Organization (ILO) and the European Commission (EC). In addition, we assessed the effectiveness of the Swiss ODL from the occupational and public health perspectives, in considering the process of reporting and recognition of occupational diseases as a measure for protecting the health of workers. Although the Swiss ODL appears to be in accordance with the ILO and EC recommendations, its role as a legal mechanism of workers’ protection is not optimal. Its effectiveness is limited by the conditions for recognising a disease as occupational, which are determined by Swiss federal law and are stricter than in other countries. The overall burden of occupational diseases has a significant economic, social and moral impact on working populations, their families and society as a whole. As such, more transparency with respect to the ODL revision and conditions for recognising occupational disease and to the data on recognised and reported cases, along with continuous education of physicians are required to enhance the effectiveness of the Swiss system of recognition and reporting of occupational diseases and protection of Swiss workers

    Delirium in older patients undergoing aortic valve replacement: incidence, predictors, and cognitive prognosis.

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    Transcatheter aortic valve replacement is increasingly performed in frail older patients who were previously ineligible for a standard surgical procedure. The objectives of this study are to determine delirium incidence, predictors, and relationship with cognitive performance at 3-month follow-up in older patients undergoing aortic valve replacement (AVR). Patients (N = 93) aged 70 years and older, undergoing transcatheter (TAVR, N = 66) or surgical (SAVR, N = 27) aortic valve replacement in an academic medical center were enrolled in this prospective cohort study. Delirium was assessed using the Confusion Assessment Method (CAM) on postoperative days 1, 2, 3, and 7. Data on patients' socio-demographics, functional status (including instrumental activities of daily living (IADL), and surgical risk scores (including Society of Thoracic Surgeons (STS) risk score), were collected at baseline. Cognitive status was assessed with the Mini-Mental Status Exam (MMSE) and the Clock Drawing Test (CDT) at baseline and 3 months after AVR. Delirium occurred in 21 (23%) patients, within the first three postoperative days in 95% (20/21) of the cases. Delirium incidence was lower in TAVR (13/66 = 20%) than SAVR (8/27 = 30%) patients, but this difference was not statistically significant (p = .298). Patients with delirium had lower baseline cognitive performance (median MMSE score 27.0 ± 3.0 vs 28.0 ± 3.0, p = .029), lower performance in IADL (7.0 vs 8.0, p = .038), and higher STS risk scores (4.7 ± 2.7 vs 2.9 ± 2.3, p = .020). In multivariate analyses, patients with intermediate (score > 3 to ≤8) and high (score > 8) STS risk scores had 4.3 (95%CI 1.2-15.1, p = .025) and 16.5 (95%CI 2.0-138.2, p = .010), respectively, higher odds of incident delirium compared to patients with low (score ≤ 3) STS risk scores. At 3-month follow-up (N = 77), patients with delirium still had lower MMSE score (27.0 ± 8.0 vs 28.0 ± 2.0, p = .007) but this difference did not remain significant once adjusting for baseline MMSE (β-coefficient 1.11, 95%CI [- 3.03-0.80], p = .248). Delirium occurred in about one in five older patients undergoing AVR, almost essentially within the first three postoperative days. Beside cognitive performance, STS risk score could enhance the identification of high-risk older patients to better target preventative interventions

    Mid-term outcomes after distally locked-to-standard primary stem exchange in 29 hip-prosthesis patients

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    AbstractBackgroundCementless locked femoral stems are used for revision surgery in patients with bone loss to induce spontaneous bone reconstruction, allowing subsequent replacement by a standard primary stem. The small number of patients and short follow-ups available to date preclude a valid assessment of this strategy.HypothesisAfter distally locked stem revision, replacement by a standard primary stem does not induce complications, and the quality of the bone reconstruction allows strong fixation of a regular primary stem.Materials and methodsWe retrospectively evaluated 29 patients in whom a distally locked femoral stem was replaced by a standard primary stem between 1998 and 2010 (cemented in 27, cementless in 2 cases). The reason for the procedure was stem breakage, stem migration, or thigh pain. Mean patient age was 63years (range, 39–78years). Outcomes were evaluated based on the Postel-Merle d’Aubigné [PMA] score and Harris Hip Score [HHS]. In addition, radiographs were obtained to assess prosthesis fixation and the Hofmann cortical index measured the bone reconstruction.ResultsThe distally locked stem was removed via a postero-lateral approach without femoral osteotomy in all the 29 cases. In one patient, an intra-operative fracture occurred during femoral preparation. Mean follow-up after the exchange procedure was 75months (range, 3–188months). Postoperative ccomplications occurred in 9 (32%) patients and consisted of chronic infection in 2 patients (after 3 and 76months), post-traumatic peri-prosthetic fractures treated with internal fixation in 3 patients (after 100, 138, and 182months), aseptic loosening in 3 patients (after 13, 39, and 122months), and recurrent instability in one patient (after 63months). All cause revision stem survival after 75months was 72% (95% confidence interval, 47%–87%). In the 19 patients who still had their revision stem at last follow-up, the mean PMA score was 16.7 (range, 13–18) and the mean HHS was 88.2 (range, 59–99). The Hofmann index remained unchanged [36.5% (range, 28%–58%) before the exchange and 32.9% (range, 20%–57%) after the exchange; P=0.129].DiscussionThis study confirms the feasibility of substituting a distally locked stem with a standard primary stem. No specific complications occurred and no technical difficulties arose when extracting the long stems. However, the 32% complication rate and, more specifically, the occurrence of loosening in 10% (3/29) of patients mandates caution in the use of this technique, which should not be proposed routinely, and suggests a need for considering cementless fixation of the standard primary stem.Level of evidenceLevel IV, retrospective study

    Role of Histamine H4 Receptor ligands in Bleomycin-induced pulmonary fibrosis

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    Fibrosis of lung tissue is a disease where a chronic inflammatory process determines a pathological remodelling of lung parenchyma. The animal model obtained by intra-tracheal administration of bleomycin in C57BL/6 mice is one of the most validated murine model. Bleomycin stimulates oxidative stress and the production of pro-inflammatory mediators. Histamine H4R have recently been implicated in inflammation and immune diseases. This study was focused to investigate the effects of H4R ligands in the modulation of inflammation and in the reduction of lung fibrosis in C57BL/6 mice treated with bleomycin. C57BL/6 mice were treated with vehicle, JNJ7777120 (JNJ, selective H4R antagonist) or ST-1006 (partial H4R agonist), ST-994 (H4R neutral antagonist) and ST-1012 (inverse H4R agonist) at equimolar doses, released by micro-osmotic pumps for 21 days. Airway resistance to inflation was assayed and lung samples were processed to measure malondialdehyde (TBARS); 8-hydroxy-2'-deoxyguanosine (8OHdG); myeloperoxidase (MPO); COX-2 expression and activity as markers of oxidative stress and inflammation. Fibrosis and airway remodelling were evaluated throughout transforming growth factor-β (TGF-β), percentage of positive Goblet cells, smooth muscle layer thickness determination. Our results indicated that JNJ, ST-994 and ST-1012 decreased inflammation and oxidative stress markers, i.e. the number of infiltrating leukocytes evaluated as lung tissue MPO, COX-2 expression and activity, TBARS and 8OHdG production. They also reduced the level of TGF-β, a pro-fibrotic cytokine, collagen deposition, thickness of smooth muscle layer, Goblet cells hyperplasia; resulting in a decrease of airway functional impairment. The results here reported clearly demonstrated that H4R ligands have a beneficial effect in a model of lung fibrosis in the mouse, thus indicating that H4R antagonists or inverse agonists could be a novel therapeutic strategy for lung inflammatory diseases
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