A note on multivariate linear regression

In this note, a hypothesis test based on relevant statistical differences is proposed for multivariate linear regression models whose design matrix rank does not equal the number of regression variables. A statistical example is also provided to illustrate the proposed hypothesis test.     

Hunger Reduction in China: An Analysis of Contextual Factors

In recent times, China has significantly reduced hunger in its populace. The main objective of this paper was to analyze some of the contextual socioeconomic factors contributing to the reduction of hunger in China, using Qualitative Interpretative Meta‐Synthesis (QIMS). The results revealed that China has followed a broad‐based and multispectral approach to reduce hunger. Factors, such as poverty alleviation; social safety nets for disadvantaged villagers; agricultural development and land reforms; regional development and equity in development activities; infrastructural development; and political‐economic reform and sustainable growth were influential in reducing hunger in China. Poverty is attributed as one of the principal contributors and is interlinked with many other dimensions. The findings of this paper are a useful guide to the Chinese government, policy‐makers, international organizations, and development practitioners.     

Lower bounds and a tabu search algorithm for the minimum deficiency problem

An edge coloring of a graph G=(V,E) is a function c:E→ℕ that assigns a color c(e) to each edge e∈E such that c(e)≠c(e′) whenever e and e′ have a common endpoint. Denoting S _v (G,c) the set of colors assigned to the edges incident to a vertex v∈V, and D _v (G,c) the minimum number of integers which must be added to S _v (G,c) to form an interval, the deficiency D(G,c) of an edge coloring c is defined as the sum ∑ _v∈V D _v (G,c), and the span of c is the number of colors used in c. The problem of finding, for a given graph, an edge coloring with a minimum deficiency is NP-hard. We give new lower bounds on the minimum deficiency of an edge coloring and on the span of edge colorings with minimum deficiency. We also propose a tabu search algorithm to solve the minimum deficiency problem and report experiments on various graph instances, some of them having a known optimal deficiency.     

Staffing-Related Deficiency Citations in Nursing Homes

There is evidence that staffing characteristics influence quality of care in nursing homes. Federal and state surveyors conduct inspections of homes to assess their compliance with regulatory standards, including requirements related to staffing. Deficiency citations are issued when these standards are not met. This article examines the relationship between operational, facility, and market characteristics and organizational performance measured as staffing-related deficiency citations. Online Survey Certification of Automated Records (OSCAR) data from 2000 through 2007 were used with multinomial logistic regression analyses to identify factors associated with deficiency citations for staffing. Chain members and facilities with poor quality of care were more likely to receive deficiency citations for staffing. Greater bed count and competition between nursing homes were associated with a decreased likelihood of deficiency citations for staffing. Staffing-related deficiencies within nursing homes vary according to various operational, facility, and market characteristics.     

Weapons of penile smooth muscle destruction: Androgen deficiency promotes accumulation of adipocytes in the corpus cavernosum

In men with erectile dysfunction, venous leakage is a common condition among non-responders to medical management and is attributed to penile smooth muscle atrophy. Androgens play a role in regulating trabecular smooth muscle growth and function. Further, androgens stimulate differentiation of progenitor cells into smooth muscle cells and inhibit their differentiation into adipocytes. We postulate that androgens exert a direct effect on penile tissue to maintain erectile function, and that androgen deficiency produces metabolic and structural imbalances in the corpus cavernosum, resulting in venous leakage and erectile dysfunction. To date, research efforts on the mechanisms by which androgens regulate penile erectile physiology have mainly focused on investigating the role of the NO/cGMP pathway. However, androgen-dependent mechanisms that regulate tissue remodeling have been poorly defined. Characterization of the molecular and cellular mechanisms by which androgens regulate corpus cavernosum structural and functional integrity would provide significant gains in knowledge and understanding of an important pathogenic process. In this review, we discuss the potential role of androgen in maintaining differentiation of progenitor cells into smooth muscle lineage and inhibition of differentiation into adipocytes. Androgen deficiency promotes differentiation into adipogenic lineage, and accumulation of adipocytes in the corpus cavernosum may contribute to erectile dysfunction.     

Testosterone therapy - what,when and to whom?

Testosterone therapy has been used for more than 60 years in the treatment of male hypogonadism. The classical forms of hypogonadism are comprised of primary testicular failure or insufficient testicular stimulation due to the lack of pituitary gonadotropins. Typical causes of primary hypogonadism are Klinefelter's syndrome, anorchia or acquired disturbances of testicular function. Secondary hypogonadism is characterized by insufficient production of pituitary gonadotropins, due either to pituitary failure or defects at the hypothalamic level. It is unequivocally accepted in clinical practice that any male with inadequately low testosterone production for his age will require androgen therapy. In addition to the classical forms of hypogonadism, the past decade of research has clearly demonstrated that, with increasing age, many men will suffer from decreasing testosterone production. About 15-25% of men over the age of 50 years will experience serum testosterone levels well below the threshold considered normal for men between 20 and 40 years of age. Studies substituting testosterone in elderly men with low serum testosterone have shown that men with clinical symptoms identical to the symptomatology of classical hypogonadism will benefit most from such therapy. Therefore, it is the general consensus to treat men with age-related hypogonadism only when clinical symptoms are present that can be potentially corrected by testosterone administration. Until recently, intramuscular injections of esters, such as testosterone enanthate, have been the mainstay of testosterone therapy. The introduction of testosterone patches has not challenged this approach, since many users of patches suffer from moderate to severe skin reactions. Some oral testosterone formulations have proven to be problematic, as absorption can be variable, bioavailability is frequently poor, due to the first-pass effect of the liver, and frequent administration is often required<citeref rid="b1"><emph>¹</emph></citeref>. Oral testosterone undecanoate avoids, at least partially, the first-pass effect of the liver. However, plasma testosterone levels generally undergo large fluctuations<citeref rid="b2"><emph>²</emph></citeref>. The large fluctuations in serum testosterone levels caused by conventional intramuscular injections result in unsatisfactory shifts in mood and sexual function in some men, which, combined with the frequency of injections, make the intramuscular mode of delivery far from ideal. Recently, a hydroalcoholic gel containing 1% testosterone has proven to be as efficient as a testosterone patch, but with fewer side-effects and a higher grade of patient satisfaction<citeref rid="b3"><emph>³</emph></citeref>^-<citeref rid="b4"></citeref><citeref rid="b5"><emph>⁵</emph></citeref>. Doses of 50-100 mg gel applied once daily on the skin deliver sufficient amounts of testosterone to restore normal hormonal values and correct the signs and symptoms of hypogonadism. The gel has been shown to be effective and successful in patients in the United States, who have benefited from its availability for almost 3 years. In the near future, intramuscular injections of testosterone undecanoate will become commercially available. Such injections have a very favorable pharmacokinetic profile, with one injection every 3 months maintaining serum testosterone well within the normal range. In phase III studies, intramuscular testosterone undecanoate proved to be as efficient as testosterone enanthate, with only one-quarter of the number of injections required and more stable serum testosterone levels. Thus, the new application modes - hydroalcoholic gel (for example, Testogel®, Schering AG, Germany) and intramuscular testosterone undecanoate (Nebido®, Schering AG, Germany) - appear to be the methods of choice in the near future, one being very suitable for hormone therapy in elderly men, the other for long-term substitution in classical forms of hypogonadism.     

Clinical experiences with testosterone therapy: prostate safety

Due to a decrease in Leydig cell function, a considerable proportion of men over 50 years of age will develop hypogonadism. Consequently, loss of libido and several other testosterone-dependent symptoms may become evident. When decreased levels of biologically available testosterone are found, and corresponding symptoms are present, these men could be eligible for testosterone substitution therapy. Testosterone treatment in testosterone-deprived men has been shown to improve general well-being, osteoporosis, muscle atrophy, libido and - if present - anemia. Despite these positive effects, testosterone treatment has to be performed with caution. Although it has not been proven that elevation of the serum testosterone level to the normal range results in a greater risk of developing prostate cancer, the effects of testosterone on a prostate cancer already present are well established. Several studies have demonstrated that testosterone treatment does not result in a significant increase in serum levels of prostate-specific antigen (PSA) or prostate volume. The long-term effects, however, are currently unknown. For these reasons, testosterone treatment should be performed only when the presence of prostate cancer is unlikely; i.e. when PSA levels are within normal limits and digital rectal examination does not reveal any suspicious findings. These examinations may still miss some small prostate cancers that could be promoted by testosterone treatment. The determination of PSA levels under testosterone treatment is necessary every 3 months, at least for the first year. Steadily rising PSA levels require immediate cessation of testosterone administration and the initiation of further diagnostic procedures (prostate biopsy), to rule out prostate cancer.     

日本内阁制变迁进程中的制度性贫困探析

进入20世纪以后,尤其是第二次世界大战以来,日本为恢复在战争中被摧毁的经济和政治制度,掀起了改革政府行政制度的热潮,以期通过行政制度指导经济的发展来寻求经济的腾飞。内阁制是行政制度的核心,因此从诞生之日起就不断地进行改革和完善以促进经济的发展。日本新宪法明确了内阁制的方向并赋予了内阁极大的权限,但最终却造成了内阁制的冗余,因此我们要取日本内阁制之精华,去日本内阁制之糟粕,健全国务院制并制定和完善相关的配套制度。     

完善西部地区生物多样性法律保护的思考

生物多样性是人类赖以生存和发展的基础和根本。广袤的西部地区是我国生态环境整体稳定和平衡不可分割的区域,其生物多样性保护也是我国生物多样性保护的重要组成部分。在经济不断发展的今天,西部地区丰富的生物及森林资源面临着生物多样性减少、外来物种入侵等多重危机。尽管我国保护生物多样性的法律制度体系已经初步形成,但无论是国家立法还是地方立法都有诸多不足之处,缺乏针对性和系统性。在西部大开发不断深入进行地过程中,亟需建立健全保护生物多样性的法律,同时不断提高地方环保立法和执法水平,从各个层面完善对西部地区生物多样性的法律保护,实现西部地区的可持续发展。     

大学生法制教育的缺失与革新

大学生是祖国的未来、民族的希望,培养德才兼备的优秀大学生是高等教育的主要任务。随着我国改革开放事业的不断推进和社会的深刻变化,大学生的思想和行为也发生了一些变化。一些大学生的罪错案例不仅在社会上引起了极大反响,也促使人们对高等院校的法制教育进行反思和重构。通过反思发现现存法制教育的缺失,通过重构提出法制教育的革新措施,以期为大学生法制教育提供思路并最终服务于高校人才培养目标。