980 research outputs found
Maternal Intuition of Fetal Gender
Purpose: Fetal gender speculation is a preoccupation of many expecting parents, and pregnant women commonly profess to intuitively know the gender of their unborn babies. This study objectively compared pregnant mothers’ perceptions of fetal gender to sonographically proven gender determinations. Also, success rates from previously published studies, noninvasive prenatal testing and a myriad of gender determination methods were observed and reported for context. Methods: All pregnant women presenting for second-trimester screening ultrasound (at 17–23 weeks gestation) in the obstetrics department of a single health center were asked to participate. A medical sonographer described the ultrasound examination, obtained appropriate consent and medical history. Each mother was asked if she had any perception as to the fetal gender and her answer documented. Mothers who had foreknowledge of fetal gender were excluded. Frequencies of actual gender were compared with observed frequencies of the maternal prediction using chi-squared test. Results: Approximately 40% (n = 411) of our study population (N = 1,026) indicated having an intuition or perception of fetal gender. These women correctly predicted the gender of their babies 51% of the time (P = 0.6571). Women who expressed a “strong” degree of intuition (n = 53) fared better, accurately predicting fetal gender at a rate of 62%, though the difference in this smaller subcohort also failed to demonstrate statistical significance (P = 0.0741). Conclusions: Intuition of fetal gender is professed by almost half of mothers though, when present, is no better at accurately predicting fetal gender than flipping a coin
The progress of early phase bone healing using porous granules produced from calcium phosphate cement
<p>Abstract</p> <p>Objective</p> <p>Bone grafting is a vital component in many surgical procedures to facilitate the repair of bone defects or fusions. Autologous bone has been the gold standard to date in spite of associated donor-site morbidity and the limited amount of available donor bone. The aim of this study was to investigate the progress of bone regeneration and material degradation of calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder compared to the use of autologous bone grafting in the treatment of "critical size defects" on load-bearing long bones of minipigs.</p> <p>Methods</p> <p>A critical size defect in the tibial metaphysis of 16 mini-pigs was filled either with autologous cancellous graft or with micro- and macroporous carbonated, apatic calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder. After 6 weeks, the specimens were assessed by X-ray and histological evaluation. The amount of new bone formation was analysed histomorphometrically.</p> <p>Results</p> <p>The semi-quantitative analysis of the radiological results showed a complete osseous bridging of the defect in three cases for the autograft group. In the same group five animals showed a beginning, but still incomplete bridging of the defect, whereas in the CPG group just two animals developed this. All other animals of the CPG group showed only a still discontinuous new bone formation. Altogether, radiologically a better osseous bridging was observed in the autograft group compared to the CPG group.</p> <p>Histomorphometrical analysis after six weeks of healing revealed that the area of new bone was significantly greater in the autograft group concerning the central area of the defect zone (p < 0.001) as well as the cortical defect zone (p < 0.002). All defects showed new bone formation, but only in the autograft group defects regenerated entirely</p> <p>Conclusions</p> <p>Within the limits of the present study it could be demonstrated that autologous cancellous grafts lead to a significantly better bone regeneration compared to the application of calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder after 6 weeks. In the early phase of bone-healing, the sole application of CPG appears to be inferior to the autologous cancellous grafts in an <it>in vivo </it>critical size defect on load-bearing long bones of mini-pigs.</p
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Application of the thorium fuel cycle
An economic analysis of the application of the thorium fuel cycle to thermal reactors is presented. (JWR
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Comparative evaluation of pebble-bed and prismatic fueled high-temperature gas-cooled reactors
A comparative evaluation has been performed of the HTGR and the Federal Republic of Germany's Pebble Bed Reactor (PBR) for potential commercial applications in the US. The evaluation considered two reactor sizes (1000 and 3000 MW(t)) and three process applications (steam cycle, direct cycle, and process heat, with outlet coolant temperatures of 750, 850, and 950/sup 0/C, respectively). The primary criterion for the comparison was the levelized (15-year) cost of producing electricity or process heat. Emphasis was placed on the cost impact of differences between the prismatic-type HTGR core, which requires periodic refuelings during reactor shutdowns, and the pebble bed PBR core, which is refueled continuously during reactor operations. Detailed studies of key technical issues using reference HTGR and PBR designs revealed that two cost components contributing to the levelized power costs are higher for the PBR: capital costs and operation and maintenance costs. A third cost component, associated with nonavailability penalties, tended to be higher for the PBR except for the process heat application, for which there is a large uncertainty in the HTGR nonavailability penalty at the 950/sup 0/C outlet coolant temperature. A fourth cost component, fuel cycle costs, is lower for the PBR, but not sufficiently lower to offset the capital cost component. Thus the HTGR appears to be slightly superior to the PBR in economic performance. Because of the advanced development of the HTGR concept, large HTGRs could also be commercialized in the US with lower R and D costs and shorter lead times than could large PBRs. It is recommended that the US gas-cooled thermal reactor program continue giving primary support to the HTGR, while also maintaining its cooperative PBR program with FRG
Bioecologia de Alabama argillacea I. Biologia em diferentes temperaturas, na cultivar de algodoeiro IAC-17
This research was carried out in order to study the biology of Alabama argillacea Hübner (1818) (Lepidoptera, Noctuidae) at constant temperatures of 20, 25, 30 and 35°C. This study was conducted in climatic chambers under relative humidity of 60 ± 10% and 14 hour photoperiod. Cotton-leaves of the cultivar IAC-17 were used as natural diet. A shortening of the larval period was observed as temperature increased from the 20 to 30°C. There was a variation between the number of instars of the cotton leafworm, and the temperature. There was no correlation between the number of instars and the size of the larvae. The pupal period decreased as temperature increased in the 20 - 30°C range. The optimum for oviposition ranged from 25 to 30°C and there was no oviposition at 20°C and 35°C. A complete life cycle was 26.88 and 17.83 days respectively at 25 - 30°C (optimum range for development). Regression equations for the different phases of the life cycle of the cotton leafworm in relation to temperature were determined.Estudou-se a biologia de Alabama argillacea Hübner (1818) (Lepidoptera, Noctuidae) em folhas de algodoeiro da cultivar IAC-17, utilizando-se câmaras climatizadas mantidas a 20, 25, 30 e 35°C, com umidade relativa de 60 ± 10% e fotófase de 14 horas. Observou-se que há um encurtamento do período larval com a elevação térmica, dentro da faixa de 20 a 30°C. O número de instares foi variável com a temperatura, mas não houve correlação entre ele e o comprimento das lagartas. Também a duração do período pupal decresceu com o aumento de temperatura, dentro da faixa de 20 - 30°C. A 20 e 35°C não ocorreram posturas, sendo que o ciclo total (ovo a adulto) foi de 26,88 e 17,83 dias respectivamente, quando o inseto foi mantido a 25 e 30°C (faixa favorável de desenvolvimento). Observou-se que, em função da elevação de temperatura, ocorreu um encurtamento do ciclo, dentro da faixa de 20 - 30°C. Foram determinadas equações de regressão simples para as diferentes fases do ciclo biológico do inseto, com relação à temperatura
Too little, too late: reduced visual span and speed characterize pure alexia
Whether normal word reading includes a stage of visual processing selectively dedicated to word or letter recognition is highly debated. Characterizing pure alexia, a seemingly selective disorder of reading, has been central to this debate. Two main theories claim either that 1) Pure alexia is caused by damage to a reading specific brain region in the left fusiform gyrus or 2) Pure alexia results from a general visual impairment that may particularly affect simultaneous processing of multiple items. We tested these competing theories in 4 patients with pure alexia using sensitive psychophysical measures and mathematical modeling. Recognition of single letters and digits in the central visual field was impaired in all patients. Visual apprehension span was also reduced for both letters and digits in all patients. The only cortical region lesioned across all 4 patients was the left fusiform gyrus, indicating that this region subserves a function broader than letter or word identification. We suggest that a seemingly pure disorder of reading can arise due to a general reduction of visual speed and span, and explain why this has a disproportionate impact on word reading while recognition of other visual stimuli are less obviously affected
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