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1.
红腹锦鸡的胚胎发育及饲养管理与疾病防治 总被引：2，自引：0，他引：2
1998～ 2 0 0 0年对红腹锦鸡的饲养繁殖与生长发育进行了研究 4～ 5月为产卵期 ,家鸡代孵孵化期为2 1d ,观察记述了家鸡代孵孵化过程中红腹锦鸡胚胎发育的主要特征 ,总结归纳了红腹锦鸡雏鸟饲养管理的主要措施及育雏期间常见的几种疾病的症状与防治措施 相似文献
2.
社会个体资源（本）是导致个体社会分化的基础，社会标准选择倾向是导致个体社会分化的依据，社会匹配是导致个体社会分化的关键。在我国社会转型时期，应建立合理的社会匹配机制， 确定推动社会发展的社会标准选择倾向，制定满足社会个体追求占有资本和社会匹配的社会措施。 相似文献
3.
Philip Johnson 《International Journal of Science Education》2013,35(7):719-737
Arising from a study which explored the development children's concept of a substance (ages 11-14), this two-part paper focuses on the idea of chemical change. Part one considers substance identity and pupils' interaction with the scientific idea of melting and boiling behaviour as a means for identification and the assessment of purity. Evidence is presented which suggests that children do not 'naturally' have a concept of substance identity which allows them to recognize chemical change as a possibility. Instead, their thinking is in terms of the history of samples. The scientific idea of identity led to a confrontation with the idea of chemical change but the pupils were unwilling to accept this phenomenon. The preference was to view the product of a chemical change as a 'mix' of the original substances rather than as a substance in its own right. Implications for teaching are discussed. Part two (in press) goes on to examine the issue of explaining chemical change. 相似文献
4.
Anna Kouppanou 《Educational Philosophy and Theory》2013,45(14):1423-1433
In this article, I set up a Heideggerian framework of research in order to investigate the phenomenon of looking at the smartphone screen, focusing especially on the desire to look, which I see as intricately connected with the desire to know and the desire to be. With a clear phenomenological disposition, supplemented by a deconstructive look via Giorgio Agamben and Bernard Stiegler, I turn to Ovid’s Metamorphoses, and especially to his myth of Narcissus, and to Lacan’s theory of the formation of the I, concluding that desire necessitates the split of the self, the self’s misrecognition in an image or in a medium or in a screen, and the subsequent reorganisation of the body, which ultimately allows for the self’s metamorphosis. After this, I discuss specifically the phenomenon of looking at the smartphone screen, emphasising that in an age that the presence of screens and of technologically produced images increases exponentially, we cannot ignore this phenomenon’s implications for educational theories and practices. Rather, we need to orient our investigations towards the interconnectedness of looking, knowing, and desiring, underlining therefore the need for an educational focus on the ways we learn to see and on the ways we learn to desire. 相似文献
5.
The development of ovarian follicular cells is controlled by multiple circulating and local hormones and factors, including
follicle-stimulating hormone (FSH) and epidermal growth factor (EGF). In this study, the stage-specific effect of EGF on FSH-induced
proliferation of granulosa cells was evaluated in the ovarian follicles of egg-laying chickens. Results showed that EGF and its receptor (EGFR) mRNAs displayed a high expression in granulosa cells from the prehierarchical follicles, including the large white follicle
(LWF) and small yellow follicle (SYF), and thereafter the expression decreased markedly to the stage of the largest preovulatory
follicle. SYF represents a turning point of EGF/EGFR mRNA expression during follicle selection. Subsequently the granulosa cells from SYF were cultured to reveal the mediation
of EGF in FSH action. Cell proliferation was remarkably increased by treatment with either EGF or FSH (0.1–100 ng/ml). This
result was confirmed by elevated proliferating cell nuclear antigen (PCNA) expression and decreased cell apoptosis. Furthermore,
EGF-induced cell proliferation was accompanied by increased mRNA expressions of EGFR, FSH receptor, and the cell cycle-regulating
genes (cyclins D1 and E1, cyclin-dependent kinases 2 and 6) as well as decreased expression of luteinizing hormone receptor
mRNA. However, the EGF or FSH-elicited effect was reversed by simultaneous treatment with an EGFR inhibitor AG1478. In conclusion,
EGF and EGFR expressions manifested stage-specific changes during follicular development and EGF mediated FSH-induced cell
proliferation and retarded cell differentiation in the prehierarchical follicles. These expressions thus stimulated follicular
growth before selection in the egg-laying chicken. 相似文献
6.
The current study examined the effectiveness of self-explanation prompts, visual signaling cues, and a combination of the two features on middle school students’ (N = 202) algebra learning. Also explored were the differential effects of features for students with faulty conceptual knowledge (evidenced by a higher prevalence of making errors during problem solving) on learning. That is, we assessed whether students who make prevalent conceptual errors predictive of algebra performance differentially benefit from design features. Participants were randomly assigned to complete 1 of 4 sets of worked example assignments supplemented with self-explanation prompts (n = 51), visual signaling cues (n = 49), both features (n = 51), or neither feature (n = 51). Worked examples supplemented with either self-explanation prompts or signaling cues led to greater learning from pre- to posttest in comparison to the worked example control, with practically meaningful effects. The effect of assignments supplemented with signaling cues was moderated by error prevalence. Those who made errors more frequently demonstrating misunderstanding of algebraic concepts (e.g., the meaning of a coefficient) benefited significantly more from visual signaling cues alone than self-explanation prompts alone or control assignments. These findings highlight the importance of considering differential effects of design features when used in combination or in isolation, particularly for struggling students. 相似文献
7.
This study examined the gender differences in outcomes related to school performance, suicidal involvement, disordered eating behaviors, sexual risk taking, substance use, and delinquent behaviors of male (n = 370) and female teenagers (n = 2,681) who self-reported a history of sexual abuse. It was found that female adolescents, by and large, engaged in internalizing behaviors and males in externalizing behaviors. Male adolescents were found to be at higher risk than females in poor school performance, delinquent activities, and sexual risk taking. Female adolescents, on the other hand, showed higher risk for suicidal ideation and behavior as well as disordered eating. Females showed more frequent use of alcohol. However, male adolescents exhibited more extreme use of alcohol and more frequent and extreme use of marijuana. Among index female adolescents, protective factors against adverse correlates included a higher emotional attachment to family, being religious or spiritual, presence of both parents at home, and a perception of overall health. Factors that augmented adverse correlates for them included a stressful school environment due to perceived high levels of substance use in and around school, worry of sexual abuse, maternal alcohol consumption, and physical abuse. For male adolescents, maternal education and parental concern appeared to be protective factors. 相似文献
8.
Susie S. Cox Laura E. Marler Marcia J. Simmering Jeff W. Totten 《Performance Improvement Quarterly》2011,23(4):49-69
Research in organizational behavior and human resources promotes the view that it is critical for managers to provide accurate feedback to employees, yet little research addresses rater tendencies (i.e., the mum effect) and attitudes that influence how performance feedback is given. Because technology has changed the nature of communication in organizations (e.g., feedback given by e‐mail), there is a need to determine how a feedback giver's preference for the delivery medium might influence the message. In this article, we develop three scales measuring the mum effect, discomfort with giving feedback, and feedback medium preference to determine feedback givers' tendencies, which may be used to improve feedback delivery. We then used these scales in a feedback situation. Findings are reported and practical implications discussed. 相似文献
9.
This study investigates the relationship between concentrations of on- and off-premises alcohol outlets and rates of child abuse and neglect. Additionally, the study seeks to locate protective features of a neighborhood's built environment by investigating the potentially moderating role that access to substance abuse treatment and prevention services plays in the relationship between alcohol outlet density and child maltreatment. Using a cross-sectional design, this ecological study utilized data from 163 census tracts in Bergen County, New Jersey, on reports of child abuse and neglect, alcohol outlets, substance abuse treatment and prevention facilities, and the United States Census to investigate the linkages between socioeconomic structure, alcohol availability, and access to substance abuse service facilities on rates of child abuse and neglect. Findings indicate areas with a greater concentration of on-premises alcohol outlets (i.e., bars) had higher rates of child neglect, and those with easier access to substance abuse services had lower rates of neglect, controlling for neighborhood demographic and socioeconomic structure. Additionally, the relationship between on-premises alcohol outlet density and rates of child neglect was moderated by the presence of substance abuse service facilities. A greater concentration of off-premises outlets (i.e., liquor stores) was associated with lower rates of physical abuse. Findings suggest that the built environment and socioeconomic structure of neighborhoods have important consequences for child well-being. The implications for future research on the structural features of neighborhoods that are associated with child well-being are discussed. 相似文献
10.
Two models of vulnerability to socioenvironmental risk were examined in 337 African American children (M = 7.8 years) recruited to overrepresent prenatal alcohol or cocaine exposure: The cumulative risk model predicted synergistic effects from exposure to multiple risk factors, and the fetal patterning of disease model predicted that prenatal insult will increase vulnerability to environmental risk. Four or more risks emerged as a threshold for poorer cognitive and behavioral outcome among the non‐substance‐exposed children, whereas substance‐exposed children showed greater vulnerability to lower levels of environmental risk. Cumulative risk was associated with increased delinquent and internalizing behaviors only for the substance‐exposed group. Results support the cumulative risk model for non‐substance‐exposed children and increased vulnerability to environmental risk among the substance‐exposed group. 相似文献
11.
Rats confronted with the onset of a light gradient display a transient increase in locomotion called theactivity response (AR) and a dark preference (Godsil & Fanselow, 2004). These experiments demonstrate that the magnitude of the AR can be blunted
with Pavlovian fear-conditioning procedures via associative and nonassociative fear. Although manifested in decreased locomotion,
the blunted AR effect was not due to increased freezing or immobility behaviors. Instead, rats displayed reduced rearing and
an increase in a class of behaviors calledstationary activity. These results suggest that the lighting differential supplied by the cue influences the topography of defensive behavior
and reduces the expression of freezing. This procedure provides a means by which to examine learned and unlearned defensive
responses to the same stimulus. 相似文献
12.
Derek R. Ford 《Educational Philosophy and Theory》2013,45(13-14):1405-1418
Air is an immersive substance that envelopes us and binds us together, yet it has dominantly been taken for granted and left out of educational and other theorizations. This article develops a conceptualization of the pneumatic common in order to address this gap. The specific intervention staged is within recent educational literature on the common by Noah De Lissovoy, Tyson E. Lewis, and Alexander Means. This literature is surveyed and analyzed in relation to educational theory, curriculum, pedagogy, and policy. Claiming that the air is a central feature of and paradigm for the common, I then concentrate on making the air conditions of the educational common explicit. I do this through a theoretical, historical, and sociological reading of air conditioning. While this explicitation is itself educational, I return to the educational common at the end of the article to ask how and what we can learn in, with, and from the air. 相似文献
13.
INTRODUCTION In recent years theory of extending modules and rings has come to play an important role in the theory of rings and modules. A module is called an extending module (or CS-module) if every submodule is essen- tial in a direct summand, or equivalently, every closed submodule is a direct summand. Although this gen- eralization of injectivity is extremely useful, it does not satisfy some important properties. For example, direct sums of extending modules need not be ex- tending;… 相似文献
14.
对药用植物云南萝芙木进行内生放线菌的分离.使用酒精和次氯酸钠对样品的根、茎、叶和果实进行表面消毒.采用两种分离培养基和三种分离方法并且分别添加重铬酸钾进行分离.共分离到17株内生放线菌. 相似文献
15.
OBJECTIVE: This study examined the relationship between reported exposure to child abuse and a history of parental substance abuse (alcohol and drugs) in a community sample in Ontario, Canada. METHOD: The sample consisted of 8472 respondents to the Ontario Mental Health Supplement (OHSUP), a comprehensive population survey of mental health. The association of self-reported retrospective childhood physical and sexual abuse and parental histories of drug or alcohol abuse was examined. RESULTS: Rates of physical and sexual abuse were significantly higher, with a more than twofold increased risk among those reporting parental substance abuse histories. The rates were not significantly different between type or severity of abuse. Successively increasing rates of abuse were found for those respondents who reported that their fathers, mothers or both parents had substance abuse problems; this risk was significantly elevated for both parents compared to father only with substance abuse problem. CONCLUSIONS: Parental substance abuse is associated with a more than twofold increase in the risk of exposure to both childhood physical and sexual abuse. While the mechanism for this association remains unclear, agencies involved in child protection or in treatment of parents with substance abuse problems must be cognizant of this relationship and focus on the development of interventions to serve these families. 相似文献
16.
Gaiter snakes (Thomnophis sirtalis) accustomed to a fish diet were injected with either saline or lithium chloride 30 min following the ingestion of earthworms. On subsequent tests at 4-day intervals, the LiCl-injected snakes showed significantly increased attack latencies to worms, which were often refused, but not to fish. Behavioral observation of feeding and concurrent tests with surface substance extracts of worm and fish indicate that chemosensory mediation is involved. 相似文献
17.
Previous place conditioning studies in mice have shown that injection of ethanol immediately before a conditioned stimulus (CS+) produces conditioned preference, whereas injection of ethanol immediately after CS+ produces conditioned aversion. In the present experiments, we examined the learning that occurs when ethanol is injected in “ambiguous“ procedures that provide the opportunity for both types of conditioning. When ethanol was given midway through the CS (Experiments 1 and 2) or both before and after the CS (Experiment 3), the direction of place conditioning was the same as when mice were exposed only to whichever contingency occurred first (a primacy effect). That is, injection of ethanol in the middle of the CS conditioned aversion, whereas injection both before and after the CS conditioned preference. Because these results support the idea that ethanol elicits both aversive and rewarding effects, they are most consistent with conditioning theories that conceptualize unconditioned stimuli (USs) as events that can activate multiple representational components. 相似文献
18.
按照开产日龄将120只缙云麻鸭（母鸭）分为10个组（组距3d）,比较各组鸭的300d总蛋数、300d总蛋重及平均蛋重。结果表明,第3组（94～96d）的300d总产蛋重显著高于第1组（88-90d）（P〈0．05）,但其他组别之间均无显著差异（P≥0．05）;10个组别的300d总产蛋数和平均蛋重也均无显著差异（P≥0．05）。 相似文献
19.
Across three pre-registered studies (n = 221 4–9-year olds, 51% female; 218 parents, 80% female; working- and middle-class backgrounds; data collected during 2019–2021) conducted in the United States (Studies 1–2; 74% White) and China (Study 3; 100% Asian), we document the emergence of a preference for “strivers.” Beginning at age 7, strivers (who work really hard) were favored over naturals (who are really smart) in both cultures (R2 ranging .03–.11). We explored several lay beliefs surrounding this preference. Beliefs about outcomes and the controllability of effort predicted the striver preference: Children who expected strivers to be more successful than naturals and believed effort was more controllable than talent preferred strivers more. Implications of the striver preference in education and beyond are discussed. 相似文献
20.
When a caloric substance is followed by a flavored substance, preference for the flavor that followed the calories can increase because of a flavor-nutrient association. We showed here that this effect is opposed by a fullness effect: consuming the caloric substance itselfreduces-consuniption of the flavor that follows. Because consumption of this flavor was less than consumption of a flavor that was given alone, there was a reduced preference for the flavor that followed the calories—an effect opposing flavor-nutrient learning. The preference for the flavor that was given alone and consumed in greater amounts seems to be due to exposure per se and is not a result of contrast. When the amount of the flavor given alone was directly controlled so that it was one half the amount of the flavor that followed the calories, preference for the flavor following the calories was no higher than when consumption of the two flavors was equal. Thus, exposure can interfere with flavor-nutrient learning, but does not enhance it. 相似文献