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991.
There is a general impression in the scientific community in our country that the way science is taught, leant and the work culture of research and management of academic and research institutions is not conducive to cutting edge research, innovation and making world leaders. Mentoring continues to be poor with some exceptions. Very often, senior scientists with long innings in science teaching and research express anguish at the status quo in spite of a number of policy documents and recommendations for change. Indian science culture (teaching, research as well as administration) is a matter of prime concern and the issues cannot be pushed under the carpet if we desire a qualitative change. Most of the institutions of higher learning churn out graduates and post graduates who are largely unemployable. There are concerns on the number of Ph.Ds and not on the quality of Ph.D. One major consequence of the weak post graduates and Ph.Ds is the non-availability of competent faculty. Weakness and lack of interest in science learning starts from school. Learning continues to be by rote which is the prime reason for our low global rank in science and mathematics competence. Teaching and research apart there are umpteen other issues in over all culture of institutions and universities engaged in science teaching and research. Few oases of excellence are exceptions in the vast pool of mediocrity. Some points which need prime attention are: adoption of a tenure track system on the pattern of US institutions; feedback on and evaluation of teaching and mentoring; bottom up approach for candid feedback on issues which require long term solutions for efficiency and sound deliverables, cultivating the culture of working in front line areas, full transparency in working and an all out exit from culture of feudalism. This transformation needs commitment on the part of the politicians who man the respective departments of science education, research and human resource development. I am sure such a cultural change and paradigm shift from the status quo does not need extra funds and can be surely ushered in without money.  相似文献   
992.
During the studies on the Turkish Braconidae, a new species Bracon (Lucobracon) iskilipus sp. n. from the Turkish Central Black Sea region was recorded. Bracon (Lucobracon) iskilipus sp. n. was described, its morphological diagnostic characters were illustrated and it was compared with the related Bracon (Lucobracon) moczari Papp.  相似文献   
993.
吴伟生  罗运祥 《植物研究》1992,12(1):123-124
本文发表了冬青属一新变种, 即短柄香冬青Ilex.suaveolens(Levl.)Loes.var.drevipetiola W.S.Wu et Y.X.Luo, var.nov.。  相似文献   
994.
Apolipoproteins such as apolipoprotein (apo) A-I, apoA-IV, and apoE are lipid binding proteins synthesized mainly in the liver and the intestine and play an important role in the transfer of exogenous or endogenous lipids through the circulatory system. To investigate the mechanism of lipid transport in fish, we have isolated some novel genes of the apoA-I family, apoIA-I (apoA-I isoform) 1–11, from Japanese eel by PCR amplification. Some of the isolated genes of apoIA-I corresponded to 28kDa-1 cDNAs which had already been deposited into the database and encoded an apolipoprotein with molecular weight of 28 kDa in the LDL, whereas others seemed to be novel genes. The structural organization of all apoIA-Is consisted of four exons separated by three introns. ApoIA-I10 had a total length of 3232 bp, whereas other genes except for apoIA-I9 ranged from 1280 to 1441 bp. The sequences of apoIA-Is at the exon-intron junctions were mostly consistent with the consensus sequence (GT/AG) at exon-intron boundaries, whereas the sequences of 3′ splice acceptor in intron 1 of apoIA-I1-7 were (AC) but not (AG). The deduced amino acid sequences of all apoIA-Is contained a putative signal peptide and a propeptide of 17 and 5 amino acid residues, respectively. The mature proteins of apoIA-I1-3, 7, and 8 consisted of 237 amino acids, whereas those of apoIA-I4-6 consisted of 239 amino acids. The mature apoIA-I10 sequence showed 65% identity to amino acid sequence of apoIA-I11 which was associated with an apolipoprotein with molecular weight of 23 kDa in the VLDL. All these mature apoIA-I sequences satisfied the common structural features depicted for the exchangeable apolipoproteins such as apoA-I, apoA-IV, and apoE but apoIA-I11 lacked internal repeats 7, 8, and 9 when compared with other members of apoA-I family. Phylogenetic analysis showed that these novel apoIA-Is isolated from Japanese eel were much closer to apoA-I than apoA-IV and apoE, suggesting new members of the apoA-I family.  相似文献   
995.
The tick fauna of Brazil is currently composed by 72 species. The state of Amazonas is the largest of Brazil, with an area of ≈ 19% of the Brazilian land. Besides its vast geographic area, only 19 tick species have been reported for Amazonas. Herein, lots containing ticks from the state of Amazonas were examined in three major tick collections from Brazil. A total of 5933 tick specimens were examined and recorded, comprising 2693 males, 1247 females, 1509 nymphs, and 484 larvae. These ticks were identified into the following 22 species: Amblyomma cajennense sensu lato, Amblyomma calcaratum, Amblyomma coelebs, Amblyomma dissimile, Amblyomma dubitatum, Amblyomma geayi, Amblyomma goeldii, Amblyomma humerale, Amblyomma latepunctatun, Amblyomma longirostre, Amblyomma naponense, Amblyomma oblongoguttatum, Amblyomma ovale, Amblyomma rotundatum, Amblyomma scalpturatum, Amblyomma varium, Dermacentor nitens, Haemaphysalis juxtakochi, Ixodes cf. Ixodes fuscipes, Ixodes luciae, Rhipicephalus microplus, Rhipicephalus sanguineus sensu lato. Ticks were collected from 17 (27.4%) out of the 62 municipalities that currently compose the state of Amazonas. The following four species are reported for the first time in the state of Amazonas: A. coelebs, A. dubitatum, H. juxtakochi, and Ixodes cf. I. fuscipes. The only tick species previously reported for Amazonas and not found in the present study is Amblyomma parvum. This study provides a great expansion of geographical and host records of ticks for the state of Amazonas, which is now considered to have a tick fauna composed by 23 species. It is noteworthy that we report 1391 Amblyomma nymphs that were identified to 13 different species.  相似文献   
996.
Micropropagation was assessed as an ex situ conservation strategy for the endangered Australian plant Pimelea spicata (Thymelaeaceae). Although regeneration of this species was achieved, several physiological problems were observed and examined. Explants of P. spicata had a higher multiplication rate on MS medium, than on ½ MS, but there was a significantly higher percentage of necrotic shoot tips on the higher salt medium. Increasing calcium concentration and gas exchange exacerbated shoot-tip necrosis. A number of hyperhydrated shoots were produced in all treatments, the cause of which could not be determined, although less hyperhydicity was observed in the ½ MS treatment. Shoots, rooted in vitro on ½ MS in the absence of plant growth regulators, were successfully acclimatised to greenhouse conditions, while direct rooting of microshoots using IBA gel treatment proved unsuccessful. This is the first report of tissue culture propagation of this endangered species.  相似文献   
997.
Exponentially growing human erythroleukemia K562 cells were permeabilized and the dose dependent decrease of DNA synthesis rate was measured after ultraviolet (UV B, 290 nm) irradiation. Cells were able to overcome 2 and 5 J/m2 UV doses, partial recovery was observed at 15 J/m2, while at high (25 J/m2) UV dose replicative DNA synthesis remained suppressed. K562 cells were subjected to synchronization prior to and after UV irradiation (24 J/m2) and 18 fractions were collected by centrifugal elutriation. Cell cycle analysis by flow cytometry did not show early apoptotic cells after UV irradiation. The gradual increase in DNA content typical for non-irradiated cells was contrasted by an early S phase block between 2.2 and 2.4 C-values after UV irradiation. Cell cycle dependent chromatin changes after ultraviolet irradiation were seen as a fine fibrillary network covering the mainly fibrous chromatin structures and incompletely folded primitive chromosomes. Based on observations after UV irradiation and on earlier results with cadmium treatment and gamma irradiation, we confirm that typical chromatin changes characteristic to genotoxic agents can be recognized and classified.  相似文献   
998.
999.
1000.
Dual-peak responses of retinal ganglion cells (RGCs) are observed in various species, previous researches suggested that both response peaks were involved in retinal information coding. In the present study, we investigated the temporal properties of the dual-peak responses recorded in mouse RGCs elicited by spatially homogeneous light flashes and the effect of the inhibitory inputs mediated by GABAergic and/or glycinergic pathways. We found that the two peaks in the dual-peak responses exhibited distinct temporal dynamics, similar to that of short-latency and long-latency single-peak responses respectively. Pharmacological studies demonstrated that the application of exogenous GABA or glycine greatly suppressed or even eliminated the second peak of the cells’ firing activities, while little change was induced in the first peak. Co-application of glycine and GABA led to complete elimination of the second peak. Moreover, application of picrotoxin or strychnine induced dual-peak responses in some cells with transient responses by unmasking a second response phase. These results suggest that both GABAergic and glycinergic pathways are involved in the dual-peak responses of the mouse RGCs, and the two response peaks may arise from distinct pathways that would converge on the ganglion cells.  相似文献   
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