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11.
Synopsis The early development of the southern mouthbrooder,Pseudocrenilabrus philander, is documented from activation until the early stages of the juvenile period. The duration of the embryonic period is about 14 days at 25°C. Development is direct and there is accelerated exogenous feeding into the embryonic period. The pattern of development and the timing of ontogenetic events and structure formation are a reflection of both internal and external environmental conditions. During mouthbrooding, oxygen uptake is facilitated by embryonic respiratory plexuses and flapping of the pectoral fins. At the time of first release from the buccal cavity, the embryos are in an advanced state of development. The switch-over from the temporary embryonic respiratory system to the adult branchial system has occurred. The yolksac serves as a supplemental source of nutrition as the embryos develop their external food-gathering abilities. The skeletal and sensory systems are sufficiently developed to allow the young to return to the safety of the female's buccal cavity. Pigmentation may provide disruptive colouration. The rate and pattern of development of another mouthbrooding cichlid,Oreochromis mossambicus, is similar to that ofP. philander despite their phylogenetic differences, and may be a consequence of similar life-history styles. 相似文献
12.
Marina I. Stanilova Valentina P. Ilcheva Nedjalka A. Zagorska 《Plant cell reports》1994,13(8):451-453
Summary The present work deals with the in vitro methods for rapid propagation, and morphogenetic potential of the rare and endangered bulb species Leucojum aestivum L., Amaryllidaceae, and Lilium rhodopaeum Delip., Liliaceae. The morphogenetic potential of different plant organs (bulb, stem, leaves and ovaries) was studied. Leaves of Leucojum aestivum L. and basal parts of the bulb in Lilium rhodopaeum Delip. possess the highest regeneration activity. Murashige and Skoog (MS) medium + 1 mg/l 6-benzylaminopurine (BAP) + 1 mg/l kinetin and Linsmaier and Skoog (LS) medium + 0.5 mg/l 1-naphthaleneacetic acid (NAA) + 0.1 mg/l kinetin were favourable for direct organogenisis from these explants. A stimulating effect of alow gamma-irradiation dose (5 Gy) upon the quantity and growth intensity of the bulbs formed by the explants in in vitro conditions is observed. 相似文献
13.
外源DNA直接导入小麦及其在育种上的应用 总被引:24,自引:0,他引:24
本研究选用两个白粒小麦品种作供体,提取其总DNA,采用花粉管直接携带法导入75(198)红粒品种受体植株。DNA导入的第一代(D1),目的性状的转化频率为1.75%和2.94%。D2代变异率显著低于D1代。对D1,D2代所得目的性状变异后代,按照常规育种程序进行D3代观察与鉴定,得到已稳定遗传的后代,从中选取保持原品种其它优良性状而籽粒为的白色的变异类型混合脱粒,获得75(198)改良新品系。 相似文献
14.
锌指基因是一种造血调节基因,编码锌指结构蛋白,主要在髓细胞中表达,促进髓细胞分化,在急性早幼粒白血病维甲酸治疗中,促使病情缓解。本文报道了我们从基因分子上研究锌指基因作用中,探索并建立了单向聚合酶链反应(PCR)扩增特定单链DNA,直接测序的新方法。它能产生质和量均佳的单链DNA,无需纯化即可直接用于测序,使复杂的测序研究简便易行,可在2,3天内完成。这种单向PCR扩增特定单链DNA直接测序的方法,经对锌指基因的cDNA测序,得到验证。此法不仅适用于疾病研究中的DNA测序,还可制各单链DNA探针,更利于基因结构组成的研究。 相似文献
15.
《Revista espa?ola de geriatría y gerontología》2023,58(6):101388
Background and objectiveMore than half of institutionalized older people need a emergency department visit annually, with high resources consumption and higher risk of adverse events, due to high complexity. Direct admission to Acute Geriatric Unit (AGU), after geriatric consultant and nursing home medical team assessment, could be a safety and effective alternative to emergency department (ED) admission.MethodsRetrospective observational study of AGU patients admitted by Nursing Home Geriatric Team between January, 1st and December, 31st, 2021. Planned admissions and SARS-CoV-2 positive patients were excluded. Medical (sociodemographic, clinical, functional and cognitive) records and outcomes data (inpatient mortality, hospital and ED lenght of stay, transfer to ED and delirium within 48 h after admission, hospital discharge location) were collected.ResultsTwo hundred and six patients directly admitted, 101 through ED (N 307). 62.5% with Barthel index <40, 65% with dementia, 56.4% with Charlson index ≥3. Inpatient mortality was 14.6% in direct admission, 20.8% in ED referral group, p = 0.14. Hospital lenght of stay was 9.61 ± 6.01 days in direct admission, 11.22 ± 5.36 days in ED group, p = 0.02. 27.7% of patients with delirium in direct admission and 36.6% in ED group; only one patient was transferred to ED, within 48 h after admission.ConclusionsDirect admission is a safety and effective alternative to ED referral in institutionalized older people after geriatric assessment, due to no increased mortality, shorter length of stay and hospital cost reduction. 相似文献
16.
摘要 目的:比较直接前方入路与后外侧入路全髋关节置换治疗股骨颈骨折的疗效及术后髋关节功能的影响因素分析。方法:选取2019年5月至2021年12月徐州医科大学附属医院收治并行全髋关节置换治疗股骨颈骨折患者96例,按照手术方法的不同分为直接前方入路组(n=48)和后外侧入路组(n=48)。观察两组围术期指标、并发症发生情况,比较两组治疗前后Harris评分、视觉模拟评分法(VAS)。并应用单因素、多因素Logistic回归分析患者术后髋关节功能的影响因素。结果:直接前方入路组下床时间、切口长度、住院时间显著短于后外侧入路组,术中失血量、术后引流量显著低于后外侧入路组,而手术时间显著长于后外侧入路组(P<0.05)。直接前方入路组术后1、3个月Harris评分显著高于后外侧入路组,VAS评分显著低于后外侧入路组(P<0.05)。两组术后并发症发生率比较,无统计学差异(P>0.05)。两组治疗6个月后髋关节功能优良率比较,差异无统计学意义(P>0.05)。多因素Logistic回归分析结果显示:体质量指数≥24 kg/m2、术后锻炼时间<3 h/d、合并骨质疏松是接受全髋关节置换治疗的股骨颈骨折患者术后髋关节功能不良的危险因素(P<0.05)。结论:直接前方入路全髋关节置换术较后外侧入路全髋关节置换术短期内优势明显,表现为对患者的创伤更小,术后疼痛程度较轻,有利于患者的髋关节功能恢复。体质量指数≥24 kg/m2、术后锻炼时间<3 h/d、合并骨质疏松是接受全髋关节置换治疗的股骨颈骨折患者术后髋关节功能不良的危险因素。 相似文献
17.
Dog-DAT: a direct agglutination test using stabilized, freeze-dried antigen for the serodiagnosis of canine visceral leishmaniasis 总被引:2,自引:0,他引:2
Linda Oskam Rob J. Slappendel Eef G.M. Beijer Nel C.M. Kroon Cor W. van Ingen Seray Özensoy Yusuf Özbel Wiepko J. Terpstra 《FEMS immunology and medical microbiology》1996,16(3-4):235-239
Abstract We have evaluated the use of an improved direct agglutination test (DAT) based on stable, freeze-dried antigen for the detection of anti- Leishmania antibodies in canine serum samples. With a cut-off value of 1:640, the sensitivity of the DAT was shown to be 100% and the specificity of the test was 98.8%. 相似文献
18.
E. Forsgren 《Proceedings. Biological sciences / The Royal Society》1997,264(1386):1283
Female preference for males successful in male-male competition is generally assumed to result in mating with high quality males. Here I report results from an experiment disentangling the effects of intra- and intersexual selection in the sand goby, Pomatoschistus minutus, a marine fish that exhibits paternal care. I show that large males are successful in male–male competition, but contrary to what one would expect, dominants are not preferred by females and are not better at taking care of the eggs. Female preference, however, correlated with the subsequent hatching success of the eggs. Thus, female choice selects for good parenting. Hence, direct benefits in the form of superior paternal care can explain female choice in this species, supporting a good parent process of sexual selection. However, choosing on the outcome of male–male competition does not enable females to mate with the ''best'' males. 相似文献
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