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61.
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The cooling power of aqueous solutions of ethylene oxide-propylene oxide copolymers are studied with a silver standard sample by using two apparatuses quench with injection and quench with agitation. For temperature T>400°C, the viscosity plays the predominant role; for T<400°C, the cooling is controlled by the polymer precipitation and the cooling rate decreases by lowering the cloud point of the polymer solution. This work demonstrates the possibility of adjusting the cooling curves by taking into account the thermodynamical properties of the polymer. 相似文献
63.
Previous studies have revealed that if mallard ducklings are given social experience with broodmates after their initial exposure to a stuffed mallard (Anas platyrhynchos) hen, they later show a visual preference for the familiar mallard over an unfamiliar redhead (Aythya americana) model. Birds kept in isolation do not make this difficult discrimination. We examined when the social experience with siblings must occur in order to contribute to maternal imprinting. We allowed 24-hr-old domestic mallard ducklings to follow a stuffed mallard hen for 30 min (training). This experience resulted in a preference for the familiar mallard over the unfamiliar redhead hen in a simultaneous choice test 48 hrs after hatching only if the birds were allowed social experience with broodmates after the training trial (i.e., from 24 to 48 hrs). Thus the visual features of the mallard hen that are necessary in order to distinguish it from the redhead hen become consolidated only after more than 1 hr into the posttraining social rearing; we term this process retroactive excitation. These results provide evidence of a nonobvious experiential contribution that conspecifics make to the development of species-typical social behavior. They also suggest that some learning and memorial processes may operate rather differently in adults and immature animals. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
64.
A George J Gui NA Jenkins DJ Gilbert NG Copeland A Veis 《Canadian Metallurgical Quarterly》1994,42(12):1527-1531
Dentinogenesis is being used as a model for understanding the biomineralization process. The odontoblasts synthesize a structural matrix comprised of Type I collagen fibrils which define the basic architecture of the tissue. The odontoblasts also synthesize and deliver a number of dentin-specific acidic macromolecules into the extracellular compartment. These acidic macromolecules may be involved in regulating the ordered deposition of hydroxyapatite crystals within the matrix. AG1 is the first tooth-specific acidic macromolecule to have been cloned and sequenced. To identify which cells of the rat incisor pulp/odontoblast complex were responsible for synthesis of AG1, in situ hybridization was used. Digoxigenin labeled sense and anti-sense AG1 riboprobes were prepared. The AG1 mRNA was found to be expressed in the mature secretory odontoblasts. Neither pulp cells nor pre-odontoblasts showed any staining with the anti-sense probes. Chromosomal localization studies placed the AG1 gene on mouse chromosome 5q21, in tight linkage with Fgf5. AG1 has been renamed Dmp1 (dentin matrix protein 1) in accordance with present chromosomal nomenclature. Mouse 5q21 corresponds to the 4q21 locus in humans. This is the locus for the human tooth mineralization disorder dentinogenesis imperfecta Type II (DI-II). These data suggest that the Dmp1 gene is involved in mineralization and is a candidate gene for DI-II. 相似文献
65.
Gilbert Baumslag Benjamin Fine Xiaowei Xu 《Applicable Algebra in Engineering, Communication and Computing》2006,17(3-4):205-217
Several suggestions are presented for developing cryptosystems, both classical and public key, using a combination of combinatorial group theory and linear groups. In particular, the Reidemeister-Schreier rewriting process is used as a one way function. These suggestions raise further questions concerning both implementation and security that are being explored in the thesis of Xu [16]. 相似文献
66.
NA Paterson JK Peat CM Mellis W Xuan AJ Woolcock 《Canadian Metallurgical Quarterly》1997,10(3):658-664
Insufficient use of anti-inflammatory drugs, such as inhaled corticosteroids and cromoglycate, may contribute to the disease burden associated with asthma. Conversely, aggressive treatment of mild disease may result in avoidable costs and/or adverse drug effects. The aim of this study was to determine the relationship between asthma severity and inhaled corticosteroid/cromoglycate use in a large (n=4,909) random sample of children, aged 8-11 yrs, in NSW, Australia. Asthma and its treatment were assessed by questionnaire responses. Asthma, defined as diagnosis plus current wheeze, was present in 901 children (18% of the sample), of whom 225 (5%) had moderate asthma, defined as asthma plus additional symptoms (sleep disturbance), utilization (hospital, casualty), or disability (reduced activity, school absence). Use of inhaled corticosteroid/cromoglycate was reported by 636 children (13% of the sample). Determinants of use included: asthma diagnosis, current wheeze, and troublesome dry nocturnal cough. There was also a strong relationship between anti-inflammatory treatment and a multicomponent asthma severity score constructed for each child. Inhaled corticosteroids and/or cromoglycate were used by 56% of the children with asthma (24% daily) and by 76% of children with moderate asthma (42% daily). Undertreatment, defined as less than daily inhaled corticosteroids/cromoglycate in moderate asthma, was identified in 130 children (14% of those with asthma or 3% of the sample). Conversely, apparently aggressive treatment, defined as inhaled corticosteroid/cromoglycate use in children with persistent minimal symptoms (asthma severity score of less than 3) was identified in 101 children (2% of the sample). Although there were significant differences between regions in the choice of anti-inflammatory drugs and in the prevalence both of undertreatment and apparently aggressive treatment, there was no clear relationship to regional utilization of emergency and hospital services for asthma. Nevertheless, the frequency of undertreatment suggests an opportunity to reduce asthma morbidity by more consistent application of current therapeutic guidelines. 相似文献
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Women and men both struggle to achieve a healthy integration of passive dependent and active autonomous strivings. However, how dependent strivings are labeled and become manifest differ for women and men. I first describe the different conceptions of male and female dependency and how such conceptions are related to sex role socialization and to societal norms and practices. I then relate these concepts to the problem of eroticism in psychotherapeutic settings and make specific recommendations for the education and training of psychologists. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
70.
JK Tong CA Hassig GR Schnitzler RE Kingston SL Schreiber 《Canadian Metallurgical Quarterly》1998,395(6705):917-921