Factors contributing to myasthenic crisis after thymectomy-a multivariate analysis study

Objective To evaluate the risk factors of myasthenic crisis (MC) after thymectomy for myasthenia gravis (MG) . Methods A retrospective study was conducted in 84 patients with MG from July 1995 to December 2009. The following factors were evaluated: sex,age,history of preoperative myasthenic crisis,Ossermen classification, steroid hormones use and anticholinesterase drugs before operation,operation methods,operation time,thymoma,

Multivariate Analysis of Femoral Adductor Muscle Contracture after Total Hip Arthroplasty in Patients with Avascular Necrosis of Femoral Head

Objective:This study is to investigate the nisk factors of femoral head contracture after total hip arthroplasty(THA)in patients with avascular necrosis of femoral head.Methods:Retrospective analysis was perfomed in 361 cases of femoral head necrosis patients taking THA fom September 2016 to December 2017.A total of 179 patents with no significant preoperative adductor muscle contraction were finally enrolled in this study.These 179 patients were further divided into two groups:contracture group(64 cases)and noncompaction group(115 cases).The chi-square test was used to compare the differences between the two groups.Risk factors were identifed by logistic regession analysis.Results:of the patients included,64 patients (35.75%)developed into end adductor muscle contracture.There were signuificant differences in limb shortening.surgical history,whether taction,surgical approach,surgical methods,and fumctional training between the two goups(P<0.05).Logistic regression analysis showed that shortness of extremity,sugical approach,effective taction,surgical history,and etiology were the factors affecting femoral head contracture after THA in patients with avascular necrosis of femoral head.Conclusions:Preoperative traction therapy,surgical methods,and postoperative functional training are the factors that affect the adductor muscle contraction after THA.

Diversity, composition and host-species relationships of epiphytic orchids and ferns in two forests in Nepal

Epiphytic plant species are an important part of biological diversity. It is therefore essential to understand the distribution pattern and the factors influencing such patterns. The present study is aimed at observing the patterns of species richness, abundances and species composition of epiphytic orchids and ferns in two subtropical forests in Nepal. We also studied the relationship of host plants(Schima wallichii and Quercus lanata) and epiphyte species. Data were collected in Naudhara community forest(CF) and the national forest(NF) in Shivapuri Nagarjun National Park. The data were analyzed using univariate and multivariate tests. In total, we recorded 41 species of epiphytes(33 orchid and 8 fern species). Orchid species abundance is significantlyhigher in CF compared to NF. Orchid species richness and abundance increased with increasing southern aspect whereas it decreased with increasing canopy cover, and fern species richness increased with host bark roughness. Orchid abundance was positively correlated with increasing bark p H, stem size, tree age and tree height and negatively correlated with increasing steepness of the area. Likewise, fern abundances were high in places with high canopy cover, trees that were tall and big, but decreased with increasing altitude and southern aspect. The composition of the orchid and fern species was affected by altitude, aspect, canopy cover, DBH, number of forks and forest management types. We showed that the diversity of orchid and fern epiphytes is influenced by host characteristics as well as host types. The most important pre-requisite for a high epiphyte biodiversity is the presence of oldrespectively tall trees, independent of the recent protection status. This means:(i) for protection, e.g.in the frame of the national park declaration, such areas should be used which host such old tall trees;and(ii) also in managed forests and even in intensively used landscapes epiphytes can be protected by letting a certain number of trees be and by giving them space to grow old and tall.

Exact Bivariate Polynomial Factorization over Q by Approximation of Roots

Factorization of polynomials is one of the foundations of symbolic computation.Its applications arise in numerous branches of mathematics and other sciences.However,the present advanced programming languages such as C++ and J++,do not support symbolic computation directly.Hence,it leads to difficulties in applying factorization in engineering fields.In this paper,the authors present an algorithm which use numerical method to obtain exact factors of a bivariate polynomial with rational coefficients.The proposed method can be directly implemented in efficient programming language such C++ together with the GNU Multiple-Precision Library.In addition,the numerical computation part often only requires double precision and is easily parallelizable.