首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Informal Exchange Networks in Formal Systems: A Theoretical Model   总被引:1,自引:0,他引:1  
Studies of the informal economy in the Third World have evolved toward defining the informal sector in relationship to the state. This article analyzes some activities that escape the control of the state, with special attention to centrally planned economies. Informal exchanges include bureaucratic favors ("connections"), clientelism, different forms of corruption, and the "parallel" system of production and marketing. I show that economic laws are not sufficient to understand the logic of these economies.  相似文献   

2.

Background

Despite policies that recommend parasitological testing before treatment for malaria, presumptive treatment remains widespread in Nigeria. The majority of Nigerians obtain antimalarial drugs from two types of for-profit drug vendors—formal and informal medicine shops—but little is known about the quality of malaria care services provided at these shops.

Aims

This study seeks to (1) describe the profile of patients who seek treatment at different types of drug outlets, (2) document the types of drugs purchased for treating malaria, (3) assess which patients are purchasing recommended drugs, and (4) estimate the extent of malaria over-treatment.

Methods

In urban, peri-urban, and rural areas in Oyo State, customers exiting proprietary and patent medicine vendor (PPMV) shops or pharmacies having purchased anti-malarial drugs were surveyed and tested with malaria rapid diagnostic test. A follow-up phone survey was conducted four days after to assess self-reported drug administration. Bivariate and multivariate regression analysis was conducted to determine the correlates of patronizing a PPMV versus pharmacy, and the likelihood of purchasing an artemisinin-combination therapy (ACT) drug.

Results

Of the 457participants who sought malaria treatment in 49 enrolled outlets, nearly 92% had diagnosed their condition by themselves, a family member, or a friend. Nearly 60% pharmacy customers purchased an ACT compared to only 29% of PPMV customers, and pharmacy customers paid significantly more on average. Multivariate regression results show that patrons of PPMVs were younger, less wealthy, waited fewer days before seeking care, and were less likely to be diagnosed at a hospital, clinic, or laboratory. Only 3.9% of participants tested positive with a malaria rapid diagnostic test.

Conclusions

Poorer individuals seeking care at PPMVs are more likely to receive inappropriate malaria treatment when compared to those who go to pharmacies. Increasing accessibility to reliable diagnosis should be explored to reduce malaria over-treatment.  相似文献   

3.
ABSTRACT Estimating abundance of carnivore populations is problematic because individuals typically are elusive, nocturnal, and dispersed across the landscape. Rare or endangered carnivore populations are even more difficult to estimate because of small sample sizes. Considering behavioral ecology of the target species can drastically improve survey efficiency and effectiveness. Previously, abundance of the black-footed ferret (Mustela nigripes) was monitored by spotlighting and generating indices of relative abundance because reintroduced populations were slow to establish. Indices, however, lack variance estimates and are costly to generate for the black-footed ferret. We therefore used spotlight surveys and live-trapping in conjunction with a robust mark-recapture estimator to improve abundance monitoring for the black-footed ferret, one of North America's most endangered carnivores. We estimated abundance of the black-footed ferret at Shirley Basin, Wyoming, USA, using correlated density estimates and Program MARK. We compared our results to 2 indices of relative abundance, minimum number alive and predicted number of ferrets from litter counts. The correlated density estimate for the black-footed ferret (R = 229; 95% CI = 161–298) was similar to minimum number alive (R = 192) and predicted number of ferrets from litter counts (R= 235). The efficiency and effectiveness of survey methods we used for the black-footed ferret were high by carnivoran standards. Our results suggest that the sampling approach we utilized can be implemented for a fraction of the cost and effort required to generate 2 indices of relative abundance for the black-footed ferret. Although we recommend managers implement a similar survey approach to monitor abundance of reintroduced populations of the black-footed ferret, analysis with sparse data sets will be problematic. Until the black-footed ferret becomes widespread and abundant at a reintroduction site, spotlighting will remain preferable as a means to generate indices of distribution and relative abundance for the black-footed ferret.  相似文献   

4.
Estimates of stability parameters for various traits in Dioscoreadeltoidea revealed that some characters, such as, per cent diosgenincontent in tubers, stem thickness and leaf breadth were fairlystable traits. Other characters, i.e. tuber length, tuber branchingand petiole length were not stable and were greatly influencedby the environment. The stability of fifteen genotypes variesfrom character to character and six genotypes were found tobe most stable for the majority of the characters. The significantgenotypic regression on the environment indicated that it shouldnot be difficult to breed D. deltoidea strains which shouldperform fairly well under diverse environmental conditions andto recognize the most desirable properties of a genotype tobe released as a variety for wide cultivation. Diosgenin, stable traits, heritable characters, environmental effect, adaptive genotypes  相似文献   

5.
6.
Although assigned mentoring relationships have typically involved same-gender matches, a growing number of programs, particularly those in schools, have begun pairing female mentors with male mentees. This practice stems, in large part, from the relative dearth of male mentors and programs’ efforts to increase the availability of youth mentoring to young males on waiting lists. We drew on secondary data from the two largest random assignment evaluations of school-based mentoring programs, the Department of Education's Student Mentoring Program and Big Brothers Big Sisters of America's School-based Mentoring, to explore the characteristics and effects of same- versus cross-gender mentoring relationships for male mentees. Our sample included 1,513 male youth from the respective programs. With only a few exceptions, male youth in same- versus cross-gender mentoring relationships experienced similar relationship processes and outcomes. Implications for research and practice are discussed along with limitations including the nonexperimental design of the study and unmeasured effects of selection bias.  相似文献   

7.
Production of official statistics frequently requires expert judgement to evaluate and reconcile data of unknown and varying quality from multiple and potentially conflicting sources. Moreover, exceptional events may be difficult to incorporate in modelled estimates. Computational logic provides a methodology and tools for incorporating analyst''s judgement, integrating multiple data sources and modelling methods, ensuring transparency and replicability, and making documentation computationally accessible. Representations using computational logic can be implemented in a variety of computer-based languages for automated production. Computational logic complements standard mathematical and statistical techniques and extends the flexibility of mathematical and statistical modelling. A basic overview of computational logic is presented and its application to official statistics is illustrated with the WHO & UNICEF estimates of national immunization coverage.  相似文献   

8.
Researchers have hypothesized that the degree to which an individual’s actual behavior approximates the culturally valued lifestyle encoded in the dominant cultural model has consequences for physical and mental health. We contribute to this line of research by analyzing data from a longitudinal study composed of five annual surveys (2002–2006 inclusive) of 791 adults in one society of foragers-farmers in the Bolivian Amazon, the Tsimane’. We estimate the association between a standard measure of individual achievement of the cultural model and (a) four indicators of psychological well-being (sadness, anger, fear and happiness) and (b) consumption of four potentially addictive substances (alcohol, cigarette, coca leaves and home-brewed beer) as indicators of stress behavior. After controlling for individual fixed effects, we found a negative association between individual achievement of the cultural model and psychological distress and a positive association between individual achievement of the cultural model and psychological well-being. Only the consumption of commercial alcohol bears the expected negative association with cultural consonance in material lifestyle, probably because the other substances analyzed have cultural values attached. Our work contributes to research on psychological health disparities by showing that a locally defined and culturally specific measure of lifestyle success is associated with psychological health.  相似文献   

9.
牙髓拟杆菌是产黑色素拟杆菌群中的一个新菌种。本试验通过对牙髓腔感染标本中分离、培养、鉴定各种细菌,发现牙髓拟杆菌主要分布在牙髓腔内,其存在与根尖周炎有无症状密切相关,此菌对氧敏感,用常规鉴定及气相色谱法与其它菌无法区别,而间接免疫荧光法是确定牙髓拟杆菌菌种和直接检测牙髓腔标本中有无此菌的一个快速、可靠的方法。  相似文献   

10.
本研究探讨了一组具有分解纤维素和农药林丹双重功能的复合菌系NSC-7的培养特性和稳定性. NSC-7在14d的培养过程中, 使稻秆分解73. 6%;用GC. MS测定结果发酵液中检测到10种化合物成分, 其中峰值较大的依次为乙酸、甘油、丁酸、丙酸:NSC. 7在. 80"C冷冻和冻干条件下保存4年后仍具有稳定的秸秆分解能力和纤维素内切酶活性;经90C高温处理30 min后, 仍能够保持分解能力,105℃处理30 min后转接2次就能恢复分解能力,显示出很高的保存稳定性和热稳定性.利用DGGE分析多次继代接种过程的培养物结果条带基本没有变化,表明NSC.7的菌种组成稳定.  相似文献   

11.
本研究探讨了一组具有分解纤维素和农药林丹双重功能的复合菌系NSC-7的培养特性和稳定性。NSC-7在14 d的培养过程中, 使稻秆分解73.6%; 用GC-MS测定结果发酵液中检测到10种化合物成分, 其中峰值较大的依次为乙酸、甘油、丁酸、丙酸; NSC-7在-80℃冷冻和冻干条件下保存4年后仍具有稳定的秸秆分解能力和纤维素内切酶活性; 经90℃高温处理30 min后, 仍能够保持分解能力, 105℃处理30 min后转接2次就能恢复分解能力, 显示出很高的保存稳定性和热稳定性。利用DGGE分析多次继代接种过程的培养物结果条带基本没有变化, 表明NSC-7的菌种组成稳定。  相似文献   

12.
13.
SYNOPSIS. Our knowledge of ascidian genetics is reviewed. Thepaper is primarily concerned with the author's past and currentwork on the colonial species Bolryllus schlosseri. Five Mendelianloci account for most of its impressive polychromatism. Breedingexperiments have substantiated the hypothesis of a single multialleliclocus for each of three enzymes (MDH, SOD, PGI) suggested byelectrophoretic patterns. The nuclei of three linkage groupshave been revealed. Self—fertilization entails a severeinbreeding depression. A specific self, nonself recognition,expressed by fusion or repulsion of contacting colonies, occursin this species also. At variance with Botryllus primigenus,fusible colonies of B. schlosseri are completely interfertile.This has allowed a more direct genetic analysis of the phenomenon,confirming the alleged control by a single multiallelic locus.In order to fuse, the confronted colonies must share at leastone allele. Young buds grafted in the tunic after removal ofall the zooids develop a new colony at the host's expense onlyif donor and host are fusible. This means that fusibility andhistocompatibility are strictly correlated. Chimerical colonies,obtained either in this way or following the resorption of oneof two fused colonies, are now being investigated for theirrecognition specificity and electrophoretic pattern. Preliminarydata indicate that both can be durably altered, suggesting thatthe allogeneic cell populations are persistent and renewing.  相似文献   

14.
15.
16.
Formal Genetics of Muscular Dystrophy   总被引:20,自引:14,他引:6       下载免费PDF全文
  相似文献   

17.
18.
19.
Perturbation methods are applied to a differential equation predator-prey model to find the approximate amplitudes and period of limit cycle solutions. In the model the feeding rate per unit predator per unit prey decreases as the prey become scare. The rigorous applicability of the perturbation technique depends on the assumptions that the limit cycle amplitude is relatively small and that near the equilibrium point the growth rate of each species is most sensitive to changes in the density of the other species. The second assumption is usually roughly satisfied in practice and examples are considered which suggest that the first assumption can be greatly relaxed.  相似文献   

20.

The effects of thermal treatment (TT) and high hydrostatic pressure treatment (HHPT) on calcium-added soybean protein 1% (w/w) aqueous dispersions at pH 7.0 were compared. High hydrostatic pressure, but not thermal treatment, improved protein solubility and colloidal stability. Despite the fact that the glycinin solubility is more affected by calcium than that of β-conglycinin, glycinin could remain in dispersion in the presence of calcium when denatured by HHPT (calcium added before or after treatment), but not when denatured by TT or without denaturing treatment. Thus, polypeptide composition of soluble aggregates depended on type of treatment. Colloidal stability and molecular weight of soluble aggregates depended on the order of application of calcium and denaturing treatment: when calcium was present during either HHPT or TT, the dispersions had higher stability and higher proportion of soluble aggregates with high molecular weight than when calcium was added after treatments. After freeze drying and re-dispersing at higher protein content (10% w/w) calcium-added dispersions subjected to HHPT formed cold-set gels that were transparent and exhibited excellent water holding capacity. Our results provide the basis for the development of ready-to-use functional ingredients.

  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号