855 resultados para Bessaga-Pelczynski`s and Milutin`s theorems on separable C(K) spaces
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A program of A (90 day moist room), B (14 day moist room) and C (7 day moist room and 7 day 50%_humidity) type curing for the R-11-Z program of durability of concrete using the automatic freeze and thaw machine (ASTM C-291) has been used in the Materials Department of the Iowa State Highway Commission since December 6, 1966. A summary of the results obtained from then until March 25, 1968, indicates that the B and C type curing are yielding very little valuable information. However, the A cure exhibits a wide range of durability factors and also groups the aggregates in an order which is related to the service record (there are definite exceptions. The biggest disadvantage to the A cure is the length of time that it takes to complete the test (90 day cure and 38 day test). The Kansas Highway Department has experimented with different cements and aggregates in order to determine which combination offers a concrete with the best durability factor possible. In an experimental test section of highway, concrete made with a Type II cement appeared to have better durability than others made with Type I cements. Because of this, a question has been raised at the Iowa State Highway Commission - Can concrete made with Type II cements, because of a lesser amount of tricalcium aluminate, yield better durability than concrete made with Type I cements?
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Understanding the influence of pore space characteristics on the hydraulic conductivity and spectral induced polarization (SIP) response is critical for establishing relationships between the electrical and hydrological properties of surficial unconsolidated sedimentary deposits, which host the bulk of the world's readily accessible groundwater resources. Here, we present the results of laboratory SIP measurements on industrial-grade, saturated quartz samples with granulometric characteristics ranging from fine sand to fine gravel, which can be regarded as proxies for widespread alluvial deposits. We altered the pore space characteristics by changing (i) the grain size spectra, (ii) the degree of compaction, and (iii) the level of sorting. We then examined how these changes affect the SIP response, the hydraulic conductivity, and the specific surface area of the considered samples. In general, the results indicate a clear connection between the SIP response and the granulometric as well as pore space characteristics. In particular, we observe a systematic correlation between the hydraulic conductivity and the relaxation time of the Cole-Cole model describing the observed SIP effect for the entire range of considered grain sizes. The results do, however, also indicate that the detailed nature of these relations depends strongly on variations in the pore space characteristics, such as, for example, the degree of compaction. The results of this study underline the complexity of the origin of the SIP signal as well as the difficulty to relate it to a single structural factor of a studied sample, and hence raise some fundamental questions with regard to the practical use of SIP measurements as site- and/or sample-independent predictors of the hydraulic conductivity.
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Although various foot models were proposed for kinematics assessment using skin makers, no objective justification exists for the foot segmentations. This study proposed objective kinematic criteria to define which foot joints are relevant (dominant) in skin markers assessments. Among the studied joints, shank-hindfoot, hindfoot-midfoot and medial-lateral forefoot joints were found to have larger mobility than flexibility of their neighbour bonesets. The amplitude and pattern consistency of these joint angles confirmed their dominancy. Nevertheless, the consistency of the medial-lateral forefoot joint amplitude was lower. These three joints also showed acceptable sensibility to experimental errors which supported their dominancy. This study concluded that to be reliable for assessments using skin markers, the foot and ankle complex could be divided into shank, hindfoot, medial forefoot, lateral forefoot and toes. Kinematics of foot models with more segments must be more cautiously used.
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This chapter covers initial placement, adjustment, and maintenance of utility facilities in, on, above or below the right-of-way of primary highways, including attachments to primary highway structures. It embodies the basic specifications and standards needed to ensure the safety of the highway user and the integrity of the highway. (2012 revision to 2005 policy.)
Resumo:
This chapter covers initial placement, adjustment, and maintenance of utility facilities in, on, above or below the right-of-way of primary highways, including attachments to primary highway structures. It embodies the basic specifications and standards needed, to ensure the safety of the highway user and the integrity of the highway. (2005 revision to 1992 policy.)
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The best indirect evidence that increased bone turnover contributes to fracture risk is the fact that most of the proven therapies for osteoporosis are inhibitors of bone turnover. The evidence base that we can use biochemical markers of bone turnover in the assessment of fracture risk is somewhat less convincing. This relates to natural variability in the markers, problems with the assays, disparity in the statistical analyses of relevant studies and the independence of their contribution to fracture risk. More research is clearly required to address these deficiencies before biochemical markers might contribute a useful independent risk factor for inclusion in FRAX(®).
Bemisia tabaci, Brevicoryne brassicae and Thrips tabaci abundance on Brassica oleracea var. acephala
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Kale Brassica oleracea var. acephala is attacked by whitefly Bemisia tabaci, aphid Brevicoryne brassicae and Thrips tabaci. One of the main reasons for extensive insecticide application is the lack of information about factors that control insect population. The objectives of this study were to investigate the relationships between predators and parasitoids, organic compound leaves, levels of leaf nitrogen and potassium, total rainfall, relative humidity, sunlight and median temperature on the abundance of whitefly, aphid, and thrips in kale genotype "Talo Roxo". The beating tray method, direct counting and magnifying lens were used to estimate the number of these pests, predators and parasitoids. Median temperature, sunlight and relative humidity correlated to the amount of leaf nonacosane, which in turn was associated with aphids population increase. A tendency in the reduction of aphids and thrips populations with increase in total rainfall was observed. The whitefly can be a harmful pest in kale producing regions of higher temperature and smaller rainfall. In regions which present moderate temperature, where there is a high incidence of aphids, genotype with low leaf wax content should be chosen. Natural enemies, especially the parasitoid Adialytus spp., can control agents of the aphids population in kale.
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Candidate gene and genome-wide association studies have not identified common variants, which are reliably associated with depression. The recent identification of obesity predisposing genes that are highly expressed in the brain raises the possibility of their genetic contribution to depression. As variation in the intron 1 of the fat mass- and obesity-associated (FTO) gene contributes to polygenic obesity, we assessed the possibility that FTO gene may contribute to depression in a cross-sectional multi-ethnic sample of 6561 depression cases and 21 932 controls selected from the EpiDREAM, INTERHEART, DeCC (depression case-control study) and Cohorte Lausannoise (CoLaus) studies. Major depression was defined according to DSM IV diagnostic criteria. Association analyses were performed under the additive genetic model. A meta-analysis of the four studies showed a significant inverse association between the obesity risk FTO rs9939609 A variant and depression (odds ratio=0.92 (0.89, 0.97), P=3 × 10(-4)) adjusted for age, sex, ethnicity/population structure and body-mass index (BMI) with no significant between-study heterogeneity (I(2)=0%, P=0.63). The FTO rs9939609 A variant was also associated with increased BMI in the four studies (β 0.30 (0.08, 0.51), P=0.0064) adjusted for age, sex and ethnicity/population structure. In conclusion, we provide the first evidence that the FTO rs9939609 A variant may be associated with a lower risk of depression independently of its effect on BMI. This study highlights the potential importance of obesity predisposing genes on depression.
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Risk factors for fracture can be purely skeletal, e.g., bone mass, microarchitecture or geometry, or a combination of bone and falls risk related factors such as age and functional status. The remit of this Task Force was to review the evidence and consider if falls should be incorporated into the FRAX® model or, alternatively, to provide guidance to assist clinicians in clinical decision-making for patients with a falls history. It is clear that falls are a risk factor for fracture. Fracture probability may be underestimated by FRAX® in individuals with a history of frequent falls. The substantial evidence that various interventions are effective in reducing falls risk was reviewed. Targeting falls risk reduction strategies towards frail older people at high risk for indoor falls is appropriate. This Task Force believes that further fracture reduction requires measures to reduce falls risk in addition to bone directed therapy. Clinicians should recognize that patients with frequent falls are at higher fracture risk than currently estimated by FRAX® and include this in decision-making. However, quantitative adjustment of the FRAX® estimated risk based on falls history is not currently possible. In the long term, incorporation of falls as a risk factor in the FRAX® model would be ideal.
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BACKGROUND & AIMS: Recent studies have described a major impact of genetic variations near the IL28B gene on the natural course and outcome of antiviral therapy in chronic hepatitis C. We therefore, aimed to explore the impact of donor and recipient genotypes of these polymorphisms on hepatitis C virus (HCV) liver graft reinfection. METHODS: Donor and recipient genotypes of IL28B rs12979860C>T single nucleotide polymorphism were determined in 91 patients with HCV liver graft reinfection, 47 of whom were treated with pegylated interferon-α (PEG-IFN-α) and ribavirin. IL28B genetic polymorphisms were correlated with the natural course and treatment outcome of recurrent hepatitis C. RESULTS: Patients requiring liver transplantation due to end-stage chronic hepatitis C appeared to be selected toward the adverse genotypes rs12979860 CT/TT compared to non-transplanted HCV-infected patients (p=0.046). Patients with the donor genotype rs12979860 CC had higher peak ALT and HCV RNA serum concentrations than those with CT/TT (p=0.04 and 0.06, respectively). No association was observed between ALT/HCV RNA serum concentrations and recipient genotypes (p>0.3). More important, donor IL28B rs12979860 CC vs. CT/TT genotypes were associated with rapid, complete early, and sustained virologic response (RVR, cEVR, SVR) to treatment with PEG-IFN-α and ribavirin (p=0.003, 0.0012, 0.008, respectively), but weaker associations of recipient genotypes with RVR, cEVR, and SVR were observed as well (p=0.0046, 0.115, 0.118, respectively). CONCLUSIONS: We provide evidence for a dominant, but not exclusive impact of the donor rather than the recipient IL28B genetic background on the natural course and treatment outcome of HCV liver graft reinfection.
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A one mile section each of thermoplastic and epoxy pavement marking materials were placed on new ACC pavement near Carroll, IA on Highway 30. The markings were evaluated for four years to see if they were suitable materials for durable pavement markings. The epoxy markings were inadvertently repainted after two years. They were performing well up to that time with little plow damage and good retroreflectivity. The thermoplastic dash lines suffered heavy snow plow damage after the first year and were repainted after the third winter. The thermoplastic edge lines performed fairly well for four years.
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The issue of corrosion of winter maintenance equipment is becoming of greater concern because of the increased use of liquid solutions of ice control chemicals, as opposed to their application in solid form. Being in liquid form, the ice control chemicals can more easily penetrate into the nooks and crannies on equipment and avoid being cleansed from the vehicle. Given this enhanced corrosive ability, methods must be found to minimize corrosion. The methods may include coatings, additives, cleansing techniques, other methods, and may also include doing nothing, and accepting a reduced equipment lifetime as a valid (perhaps) trade off with the enhanced benefits of using liquid ice control chemicals. In reality, some combination of these methods may prove to be optimal. Whatever solutions are selected, they must be relatively cheap and durable. The latter point is critical because of the environment in which maintenance trucks operate, in which scrapes, scratches and dents are facts of life. Protection methods that are not robust simply will not work. The purpose of this study is to determine how corrosion occurs on maintenance trucks, to find methods that would minimize the major corrosion mechanisms, and to
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OBJECTIVE: To evaluate the effects of nutrient intake and vitamin D status on markers of type I collagen formation and degradation in adolescent boys and girls. DESIGN: Cross-sectional study. SETTING: Canton of Vaud, West Switzerland. SUBJECTS: A total of 92 boys and 104 girls, aged 11-16 y. Data were collected on height, weight, pubertal status (self-assessment of Tanner stage), nutrient intake (3-day dietary record) and fasting serum concentration of 25-hydroxyvitamin D (25OHD), and markers of collagen formation (P1NP) and degradation (serum C-terminal telopeptides: S-CTX). RESULTS: Tanner stage was a significant determinant of P1NP in boys and girls and S-CTX in girls. Of the nutrients examined, only the ratio of calcium to phosphorus (Ca/P) was positively associated with P1NP in boys, after adjustment for pubertal status. 25OHD decreased significantly at each Tanner stage in boys. Overall, 15% of boys and 17% of girls were identified as being vitamin D insufficient (serum 25OHD <30 nmol/l), with the highest proportion of insufficiency at Tanner stage 4-5 (29%) in boys and at Tanner stage 3 (24%) in girls. A significant association was not found between 25OHD and either bone turnover marker, nor was 25OHD insufficiency associated with higher concentrations of the bone turnover markers. CONCLUSIONS: The marked effects of puberty on bone metabolism may have obscured any possible effects of diet and vitamin D status on markers of bone metabolism. The mechanistic basis for the positive association between dietary Ca/P ratio and P1NP in boys is not clear and may be attributable to a higher Ca intake per se, a critical balance between Ca and P intake or higher dairy product consumption. A higher incidence of vitamin D insufficiency in older adolescents may reflect a more sedentary lifestyle or increased utilisation of 25OHD, and suggests that further research is needed to define their requirements. SPONSORSHIP: Nestec Ltd and The Swiss Foundation for Research in Osteoporosis.