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Epidemiological studies enable us to analyze disease behavior, define risk factors and establish fundamental prognostic criteria, with the purpose of studying different types of diseases. The aim of this study was to determine the epidemiological characteristics of canine mammary tumors diagnosed during the period 2002-2012. The study was based on a retrospective study consisting of 1,917 biopsies of intact dogs that presented mammary gland lesions. Biopsies were sent to the Department of Pathology FMVZ-UNAM diagnostic service. The annual incidence of mammary tumors was 16.8%: 47.7% (benign) and 47.5% (malignant). The highest number of cases was epithelial, followed by mixed tumors. The most commonly diagnosed tumors were tubular adenoma, papillary adenoma, tubular carcinoma, papillary carcinoma, solid carcinoma, complex carcinoma and carcinosarcoma. Pure breeds accounted for 80% of submissions, and the Poodle, Cocker Spaniel and German Shepherd were consistently affected. Adult female dogs (9 to 12 years old) were most frequently involved, followed by 5- to 8-year-old females. Some association between breeds with histological types of malignant tumors was observed, but no association was found between breeds and BN. Mammary tumors in intact dogs had a high incidence. Benign and malignant tumors had similar frequencies, with an increase in malignant tumors in the past four years of the study. Epithelial tumors were more common, and the most affected were old adult females, purebreds and small-sized dogs. Mammary tumors in dogs are an important animal health problem that needs to be solved by improving veterinary oncology services in Mexico.  相似文献   

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River Atna is situated in south-eastern Norway and stretches from approx. 1400 m a.s.l. in the Rondane Mountains, through Lake Atnsjøen, at 701 m a.s.l.; to the confluence with River Glomma at 338 m a.s.l. The catchment area is 1323 km2, oligotrophic and very susceptible to acid precipitation. The river water is very poor in nutrients and ions, and pH varies from 5.0 to 7.2. Samples were taken each year from 1987 to 2002 at three to five localities from 1280 to 380 m a.s.l. Insect larvae were collected by Surber sampling and by kick sampling. Malaise traps were used to collect adults of Plecoptera, Trichoptera, Chironomidae and Limoniidae. A total of 16 taxa of Ephemeroptera, 24 taxa of Plecoptera, 39 taxa of Trichoptera, 125 taxa of Chironomidae and 52 taxa of Limoniidae, were identified. Our results from Atna provide some support for a zonation of the river based on zoobenthos. The occurrence and abundance of functional groups among the Plecoptera, Trichoptera, and Chironomidae are discussed in relation to the River Continuum Concept (RCC). Our conclusion is that grazers dominate in the zoobenthos in streams in the treeless alpine region in Norway. Natural lakes, which occur in most watercourses in Norway, appear to cause a disturbance in relation to the original RCC concept, as the zoobenthos community in and below the lake outlet is dominated by collectors (filter feeders). The pattern found in the Atna watercourse is probably a general pattern for a northern watercourse in the Holarctic, where the glacial periods created lakes in most watercourses. The results of the long term sampling in Atna are discussed in relation to the practicalities and the cost-benefit of zoobenthos in efficient bio-monitoring in rivers.  相似文献   

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Students learn best when they are focused and thinking about the subject at hand. To teach physiology, we must offer opportunities for students to actively participate in class. This approach aids in focusing their attention on the topic and thus generating genuine interest in the mechanisms involved. This study was conducted to determine if offering voluntary active learning exercises would improve student understanding and application of the material covered. To compare performance, an anonymous cardiorespiratory evaluation was distributed to two groups of students during the fall (control, n = 168) and spring (treatment, n = 176) semesters. Students in both groups were taught by traditional methods, and students in the treatment group had the option to voluntary participate in two additional active learning exercises: 1) a small group discussion, where students would discuss a physiology topic with their Teaching Assistant before running BIOPAC software for the laboratory exercise and 2) a free response question, where students anonymously responded to one short essay question after the laboratory exercise. In these formative assessments, students received feedback about their present state of learning from the discussion with their peers and also from the instructor comments regarding perceived misconceptions. As a result of the participation in these activities, students in the treatment group had a better overall performance [χ(2) (degree of freedom = 1) = 31.2, P < 0.001] on the evaluation (treatment group: 62% of responses correct and control group: 49%) with an observed difference of 13% (95% confidence interval: 8, 17). In conclusion, this study presents sufficient evidence that when the opportunity presents itself, students become active participants in the learning process, which translates into an improvement in their understanding and application of physiological concepts.  相似文献   

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Secular changes in the body dimensions of newborns from three different geographical localities are compared. Anthropometrical data of infants born in 1987 and in 2002 as a result of singleton full-term non-pathological postpartum were collected from medical records of children's out-patient clinics in three geographical localities: two big cities-Moscow and Saratov-and the town of Khvalynsk (Saratov region). The total number of newborns used in the analysis was 1,174. Body length and weight at birth from 1987 to 2002 increased in Moscow and Saratov, while in Khvalynsk there was a significant decrease of body length for boys. There is also a trend towards decrease of body weight in Khvalynsk boys and girls. It may be assumed that the changes in body sizes of newborns may be connected with socio-economic changes.  相似文献   

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We briefly summarize the history of the rise of comparative physiology in China, the research work focused on by domestic and international counterparts in the field of comparative physiology of China, and international academic exchange and collaboration during this period. We also introduce some of the interesting model systems used in past and current research. This paper is based on documents in historical materials such as the proceedings of the 1st (August 1988) to 6th (October, 2007) Comparative Physiology Academic Session of the Chinese Association for Physiological Sciences, collected physiological works in commemoration academic papers of the 70th (1926-1999) and 80th anniversary of the Chinese Association for Physiological Sciences (1926-2006), CBP and the Physiology History of China, and the authors' own research experience.  相似文献   

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OBJECTIVE--To investigate whether outdoor air pollution levels in London influence daily mortality. DESIGN--Poisson regression analysis of daily counts of deaths, with adjustment for effects of secular trend, seasonal and other cyclical factors, day of the week, holidays, influenza epidemic, temperature, humidity, and autocorrelation, from April 1987 to March 1992. Pollution variables were particles (black smoke), sulphur dioxide, ozone, and nitrogen dioxide, lagged 0-3 days. SETTING--Greater London. OUTCOME MEASURES--Relative risk of death from all causes (excluding accidents), respiratory disease, and cardiovascular disease. RESULTS--Ozone levels (same day) were associated with a significant increase in all cause, cardiovascular, and respiratory mortality; the effects were greater in the warm seasons (April to September) and were independent of the effects of other pollutants. In the warm season an increase of the eight hour ozone concentration from the 10th to the 90th centile of the seasonal change (7-36 ppb) was associated with an increase of 3.5% (95% confidence interval 1.7 to 5.3), 3.6% (1.04 to 6.1), and 5.4% (0.4 to 10.7) in all cause, cardiovascular, and respiratory mortality respectively. Black smoke concentrations on the previous day were significantly associated with all cause mortality, and this effect was also greater in the warm season and was independent of the effects of other pollutants. For black smoke an increase from the 10th to 90th centile in the warm season (7-19 microg/m3) was associated with an increase of 2.5% (0.9 to 4.1) in all cause mortality. Significant but smaller and less consistent effects were also observed for nitrogen dioxide and sulphur dioxide. CONCLUSION--Daily variations in air pollution within the range currently occurring in London may have an adverse effect on daily mortality.  相似文献   

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The subtyping of 350 isolates of HIV-1, isolated on the territories of 38 subjects of the Russian Federation, was carried out. The analysis was made by the method of the comparative heteroduplex mobility assay, as well as by the determination of the sequence of genes env [correction of ens] (gp 120) and gag (p17-p24). The study revealed that more than 50% of all cases of HIV-1 infection were caused by closely related variants of subtype A virus. The number of cases of HIV-1 infection caused by recombinant virus A/B was not less than 25%. The total number of cases caused by viruses of subtypes C, D, E, F and H was not more than 5%.  相似文献   

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The prevalence of Echinococcus granulosus in sheep was examined in Sardinia between June and September 1987-1988. Of the examined sheep 243 were being pastured in fenced fields while 1084 were being pastured in open fields. An infection rate of 1.6% was recorded in the first group of sheep, and 86.7% in the second. The prevalence rate differed in various parts of the region, ranging from 79.4% (Oristano province) to 95% (Nuoro province). Of the parasitized sheep 7.9% harboured only fertile cysts, and 74.1% only sterile cysts. The latest figure is surprising compared to data previously reported in the literature. Most of the sheep examined were infected in both organs (67.4%) but only 27.4% of these showed a massive infection with over 10 hydatid cysts. The variation in prevalence rate and epidemiological implications are discussed.  相似文献   

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To study the cytology profile of cervical smears and the respective prevalence and incidence of certain cervico-vaginal infections detectable by routine Pap smear cytology in Lebanese women from 2002 to 2006. Pap smear cytology results were compiled from the archives of the Institut National de Pathologie for the period extending from 2002 until 2006. This study covered 118,230 cervical specimens obtained from Lebanese women attending clinics and hospitals in all the five districts of Lebanon; prevalence and incidence rates for infections detectable by routine Pap smear examination were determined. A rise in prevalence of these infections by 2.1 percent (2,555) from 2002 to 2006 was revealed. A doubling of Pap smears showing HPV-associated changes was detected (1.4 percent in 2002 to 2.9 percent in 2006), and a simultaneous almost 7-fold increase of Atypical Squamous Cells of Undetermined Significance (ASCUS) cytology was detected during this period; the rise in ASCUS cytology was age-dependent. Moreover, a 60 percent increase in prevalence of bacterial vaginosis (2.3 percent in 2002 to 3.7 percent in 2006) and a more than 3-fold decline in Trichomonas vaginalis infection (1 percent in 2002 to 0.3 percent in 2006) were also noted in this population during this period. An increase in the prevalence and incidence of cervico-vaginal infections detectable by Pap smear cytology in Lebanese women was revealed from 2002 to 2006. Such changes could point to recent modifications of sexual and health behaviours in the Lebanese community.  相似文献   

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Past research has shown that the labor market behavior of wives is discontinuous and affected by family events. Specifically, both cross‐sectional and panel data indicate that fertility decreases the period that a married woman spends working. Each birth appears to decrease labor force participation by one year or more. The present study attempts to specify these effects more completely. The variation in work patterns for each parity progression is examined to determine whether the fertility‐work effect is due to a few women who leave the labor force for an extended period during childbearing or due to a large number of women who have intermittent work histories. The analysis uses a national sample of women who were high school sophomores in 1955 and followed up as adults in 1970 and for whom retrospective data for each of the intervening years were obtained. Only married women with uncomplicated marital histories are included in the present study. We find dramatic evidence for two distinct types of response to childbearing. Women tend either to work almost continuously throughout the period or to drop out of the labor force for a very extended period of time after first birth.  相似文献   

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