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41.
42.
Pei-Yi Lin Yi-Ya Fang Su-Ping Wang Mei-Yun Tai Yuan-Feen Tsai 《Die Naturwissenschaften》2012,99(3):185-189
After extinction, the reappearance of a conditioned response induced by an unconditioned stimulus which is weaker than that
used during the conditioning training indicates that the extinction procedure does not eliminate the original conditioned
memory. Recent studies on fear conditioning have shown that rats exhibited little or no recovery of conditioned responding
if the time interval between fear acquisition and extinction was short, suggesting that the extinction process may erase the
original conditioning trace in this situation. In the present study, a saving experiment was conducted in rats to investigate
whether an aversive response could be recovered following extinction training with different time intervals after acquisition
of conditioned taste aversion (CTA). Male Long–Evans rats developed CTA by associating a 0.2% sucrose solution with malaise
induced by intraperitoneal injection of 4 ml/kg 0.15 M LiCl and were subjected to extinction training with an interval of
5 h (5H group) or 24 h (24H group) after acquisition of CTA. Rats in the 5H group, but not in the 24H group, exhibited no
aversive responding to the sucrose solution followed by the injection of a lower dose of LiCl (1 ml/kg). These findings indicate
that the extinction procedure administered at different time points following the acquisition of CTA affects recovery of extinguished
aversive memory and suggest that an unlearning process may be involved in the mechanisms of CTA extinction with short intervals
between acquisition and extinction. 相似文献
43.
Gyu-Cheol Lee Weon-Hwa Jheong Gyoo Seung Jung Sung-Ae Oh Min-jeong Kim Ok-Jae Rhee Sujeong Park Chan Hee Lee 《Food and environmental virology》2012,4(3):115-123
RT-PCR, nucleotide sequencing, and phylogenetic analysis were performed for genotyping and molecular characterization of noroviruses isolated from Korean groundwater. Among 160 samples collected from 80 sites between 2008 and 2010, 14 samples (8.7?%) from 12 sites were positive for noroviruses (NoVs). The percentages of NoV-positive samples in 2008, 2009, and 2010 were 22.2, 3.2, and 0?%, respectively, representing a yearly decrease. GII-positive samples (n?=?9, 5.6?%) outnumbered GI-positive samples (n?=?5, 3.1?%). The genotypes of the GI NoVs were GI.2, GI.5, and GI.6, and the genotypes of the GII NoVs were all GII.4. One sample, HM623465, was very similar to CUK-3 and CBNU2 and two GII.4 sequences isolated from the stool of Korean gastroenteritis patients. A BLASTN search revealed several nucleotide sequences highly similar to those of NoVs isolated in this study. The original isolation sources for these similar NoVs were mostly stool (n?=?731, 80.0?%) and groundwater (n?=?135, 14.8?%), and all the countries from which they were isolated were almost in Asia (96.0?%); specifically, China (n?=?192, 21.0?%), Japan (n?=?383, 41.9?%), Korea (n?=?296, 32.4?%), and other Asian countries (n?=?6, 0.7?%). These results suggest that Korean groundwater might be contaminated with NoVs from the stool of infected patients and that these NoVs in turn cause new cases of gastroenteritis through a typical fecal-oral route with region-specific circulation. Therefore, it is important to properly treat sewage, which may include waterborne viruses and manage point sources in groundwater for national health and sanitation. In addition, continuous molecular surveillance remains important for understanding circulating NoVs. 相似文献
44.
Rumi Chan Eiko Obuchi Katsumi Katoh Hom Nath Luitel Katsuyuki Nakano 《环境科学学报(英文版)》2013,25(7):1419-1423
TiO2 immobilized on SiO2 (TiO2/SiO2) have been prepared by sol-gel method and various ions of transition metals (Cr3+, Co2+, Ni2+, Cu2+, and Zn2+) were doped on the photocatalyst using wet impregnation method under reducing calcination atmosphere. The photocatalytic activity of metal doped TiO2/SiO2 towards phenol degradation under black light irradiation were investigated and compared with undoped TiO2/SiO2. The results showed that the photoresponse of Cu2+ and Zn2+ doped TiO2/SiO2 were larger than undoped TiO2/SiO2, indicating that the photogenerated carriers were separated more efficiently in Cu2+ and Zn2+ doped TiO2/SiO2. The reactivity was in the order of Cu2+ > Zn2+ > Ni2+ > Cr3+ > Co2+. The different photoreactivity was ascribed to combine effect of the different ionic radii and photocorrison tendency of the dopants. The sample was also characterized by surface analytical methods such as X-ray diffraction, scanning electron micrograph/electron dispersive X-ray analyzer and UV-Vis absorption spectrum. 相似文献
45.
江西西华山钨矿床流体包裹体特征及成矿流体来源 总被引:1,自引:0,他引:1
本文对江西西华山钨矿床的石英流体包裹体进行了岩相学和显微测温分析,研究了石英流体包裹体的气、液相组分及碳、氢、氧同位素特征。结果表明,石英中流体包裹体十分发育,包裹体类型有NaCl-H2O(盐水)包裹体(Ⅰ)和CO2-H2O包裹体(Ⅱ),且以前者为主。包裹体均一温度在200℃~280℃,平均249.5℃;盐度为7.89%~13.95%,平均10.73%;成矿流体密度为0.628g/cm3~0.895g/cm3,平均0.795g/cm3,属低盐度低密度范畴;压力平均值为64.01MPa,对应的成矿深度平均值为6.45km。成矿热液气相成分以H2O为主,CO2含量低;液相成分阴阳离子浓度都很低,相对富钠和氯,流体离子类型大致呈Na+-K+-Cl--SO42-型。成矿流体基本来自岩浆水,部分可能有变质水的加入;流体中碳主要由岩浆水提供,少数由地幔源提供。 相似文献
46.
Can Labor Out-Migration Reduce Firewood Consumption by Rural Households in Western Mountainous China
Abstract The relationship between out-migration of labor in the Qinling mountain area and households’ firewood consumption is explored. Migration and remittances reduce households’ firewood consumption due to increases in both income and opportunity cost of firewood collection. Previous studies have been equivocal because they ignored uncertainty in household economy, which is widespread in forest areas of less developed countries. This study provides additional insight by considering vulnerability and subjective assessment of poverty generated by unstable income and an uncertain future. We provide evidence that the amount of firewood consumed depends on income and opportunity cost of firewood collection, but also on a prudent consumption strategy, due to farmers’ subjective assessment of their future possible poverty. We also find out-migration of labor can reduce per capita firewood consumption but subjective poverty also acts against reduction of firewood consumption. 相似文献
47.
48.
Phylogeographic structure of false clownfish, Amphiprion ocellaris, explained by sea level changes on the Sunda shelf 总被引:3,自引:0,他引:3
The phylogenetic structure of the anemonefish Amphiprion ocellaris was established based on sequence data generated for the 5′ end of the cytochrome b (cytb) gene at 11 sites throughout Southeast Asia. Considerable genetic structuring was observed throughout the range of
A. ocellaris. The region has a complex geography, with the Sunda shelf having been exposed during the lower sea levels associated with
periods of glaciation. The direction of subsequent flooding of the Sunda shelf, as a direct consequence of the retreating
glacial sheets, can be predicted based on the major river drainage systems in the region. Much of the phylogeographic structure,
including levels of intra-site genetic variation, can be explained in terms of the “seeding” of sites on the Sunda shelf,
by those on the shelf rim, as sea levels rose. We often found surface ocean currents in the region, which should influence
larval dispersal, to be poorly correlated with phylogeographic structure. Several geographically close sites, which appear
to be connected by surface currents, showed significant genetic stratification. We hypothesise that the phylogeographic structure
of A. ocellaris is more reminiscent of the Pleistocene sea level changes than surface currents. The high contribution of sea level changes
to the phylogeographic structure was also supported by several missing haplotypes in the generated spanning network. Cytb
DNA sequences generated for recently recruited A. ocellaris individuals sampled from Singapore indicate that, on a local scale, there is a directional inflow of recruits, which is dependent
on the monsoon seasons. The nature of dispersal and genetic structure of reef fish species found on the Sunda shelf is clearly
complex, and should take into consideration past phylogeographic events.
Received: 13 November 1999 / Accepted: 12 July 2000 相似文献
49.
50.