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171.
CRISM indicates the presence of water ice patches in Richardson crater, located on Mars’ southern polar region at the area of the seasonal ice cap. Numerical simulations suggest that the maximum daytime temperature of the ice at these locations is between 195 and 220 K during local spring. Previous studies suggest that at these temperatures liquid interfacial water could be present. Here, for the first time, we provide an example where the environmental conditions allow for the formation of such liquid films on present day Mars at the southern hemisphere. The upper bound estimated H2O loss during the presence of these water ice patches is approximately 30 μm between Ls = 200 and 220, though it may be as low as 0.1 μm depending on the ambient water vapor. The upper bound value is larger than the expected condensation thickness in autumn; however, it may still be realistic due to CO2 gas jet generated deposition and possible subsequent accumulation on mineral grains. The presence of this interfacial water may have impact on local chemical processes along with astrobiological importance. 相似文献
172.
Wiesław Wiśniewolski Janusz Górczyński Wiesław Madry 《Aquatic Sciences - Research Across Boundaries》1989,51(3):249-259
Width of the first ray of the pectoral fin has been measured in two places for 154 young and 89 adult wels. Statistical relationships between the above characters and fish length as well as its maturity and sex have been proved. Three models of discriminant function for identification of adult fish sex have been derived and verified. The accuracy of sex separation has been 89,5% in a standard sample of wels, and 90,6% in a routine sample, after an adjustment in the procedure. 相似文献
173.
Artificial light at night: implications for early life stages development in four temperate freshwater fish species 总被引:1,自引:0,他引:1
Anika Brüning Franz Hölker Christian Wolter 《Aquatic Sciences - Research Across Boundaries》2011,73(1):143-152
Flora and fauna have both evolved under a natural cycle of light and dark. But especially in urban areas, the night is now
increasingly disturbed by artificial light. Many traits and behaviours in fish are triggered by a circadian clock, for example
hatching and swim bladder inflation, which predominantly take place at dusk or night. As lighting becomes brighter and extends
farther into rural areas, the distinction between day and night becomes increasingly blurred. Therefore, the loss of diurnal
trigger by artificial light at night was hypothesized having deleterious effects on these traits and impact fish reproduction.
To assess these effects, eggs of four native freshwater fishes, Eurasian perch Perca fluviatilis, roach Rutilus rutilus, bleak Alburnus alburnus and chub Leuciscus cephalus, were incubated under two different light conditions: a photoperiod of 14 h light:10 h darkness (LD) and continuous illumination
(LL). The time to hatch and swim bladder inflation was recorded. The species showed inconsistent reactions to the light treatments.
In roach and bleak, the time to 50% hatch was longer in LL, whereas continuous lighting had an accelerating effect in chub.
Incubation in LL elongated the hatching period in perch and roach and, in perch, the onset of darkness seemed to trigger hatching.
The swim bladder inflation was significantly promoted by continuous light in chub and bleak but was not affected in roach.
In conclusion, nocturnal artificial illumination could have an effect on hatching and initial swim bladder filling by masking
the day–night-change and thereby diminish the trigger effect. However, the reactions were species specific and the increase
in variation indicated a lack of diurnal triggering, whilst a general deleterious effect of artificial light at night has
not been identified on early life stages. 相似文献
174.
175.
176.
G. R. Huguenin A. E. Lilley W. H. McDonough M. D. Papagiannis 《Planetary and Space Science》1964,12(12):1157-1167
Radio noise observations at frequencies of 0·700 Mc and 2·200 Mc were made at altitudes between 3000 and 11,000 km from a Blue Scout Jr. high-altitude rocket probe on 30 July 1963. A steady background flux of (7·5−3+6) × 10−19 W m−2)(c/s)−1 at 0·700 Mc and (1·8+1.0−0.5 × 10−19 W m−2 (c/s)−1 at 2·200 Mc was observed. Assuming a galactic origin of the observed fluxes at both frequencies, the averaged sky brightnesses are b(0·700 Mc) = (6−3+5) × 10−20 W m−2 (c/s)−1 sr−1b(2·200 Mc) = (1.4+1.0−0.5 × 10−20 W m−2 (c/s)−1 sr−1 The observed brightness at 2·200 Mc is in reasonable agreement with the results of other observers. The apparent brightness at 0·700 Mc is, however, greater than was expected from previous observations. An alternative source of the 0·700 Mc flux in the terrestrial exosphere, as well as characteristics of several noise bursts observed during the flight, is briefly discussed. 相似文献
177.
Comprehensive distribution patterns of physical and chemical characteristics have been obtained from a series of cruises in Liverpool Bay. The marked feature of these distributions was their temporal variability, suggesting that the surface residual circulation is also temporally variable. The influence of wind stress upon the circulation pattern and hence water quality of this sea area is illustrated. 相似文献
178.
河南既是农业大省又是中国重要的粮食主产区,农用地流转顺畅及适度规模经营对区域经济发展和国家粮食安全产生重要影响。借助于土地使用权评估的基本方法,并使用土地承包经营权的权属特性进行修正,构建了土地承包经营权流转价格模型,并对典型区域沁阳市西万村进行了实证分析。结果表明,土地承包经营权流转价格应该包括经济价格、社会价格和修正价格。价格模型的应用,应甄别理论价格和实际流转费用的区分,农用地流转后经营项目没有转变,流转价格为经济价格和社会保障价格是总和。农用地流转后经营项目发生转变,比如耕地改种经济作物,流转价格则是经济价格、社会价格与修正价格三者的总和。收益分配格局存在复杂性,流转收益应在流出方、流入方、管理者和所有者之间合理、公平分配。政府应建立合理有序的农用地承包经营权流转市场,并以农用地流转市场为载体,构建农用地流转价格体系。 相似文献
179.
Karaevskaya E. S. Demidov N. E. Kazantsev V. S. Elizarov I. M. Kaloshin A. G. Petrov A. L. Karlov D. S. Schirrmeister L. Belov A. A. Wetterich S. 《Izvestiya Atmospheric and Oceanic Physics》2021,57(10):1254-1270
Izvestiya, Atmospheric and Oceanic Physics - The archaeal composition of permafrost samples taken during the drilling of frozen marine sediments in the area of the Barentsburg coal mine on the east... 相似文献
180.
M.G. Audley-Charles 《Tectonophysics》1985,119(1-4)
The anomalous updomed morphological expression of Sumba island, its enigmatic lack of strong Neogene deformation and the northward morphological indentation of southern Sumbawa and Flores require explanation.The stratigraphy of Sumba may be correlated with the Cretaceous to Miocene part of the Timor allochthon. The sedimentary and eruptive rock succession in Sumba shows remarkable similarities with the allochthonous Palelo, Wiluba and Cablac deposits of Timor. In both islands the Cretaceous parts of these sequences are regarded as characteristic of fore-arc deposits built on thin continental crust.The Timor nappe is interpreted as a 5 km thick tectonic flake of the Banda fore-arc thrust onto the Australian continental margin in the mid-Pliocene collision. The postulated Sumba nappe has not yet been thrust onto the Australian margin which, in the Sumba region, has not yet converged as close to the arc as in the Timor area. The postulated Sumba nappe is interpreted as a diapiric elongated dome of the Sunda fore-arc that is being squeezed by the converging margin of Australia against the volcanic islands of Sumbawa and Flores.The absence of indications on the seismic reflection profiles for the presence of the thrust fault of the Sumba nappe may perhaps be explained by the thrusts being nearly horizontal within flat-lying strata.The Savu thrust is correlated with the probably older (pre-Late Pliocene) Wetar Suture as a major southward dipping lithospheric rupture. East of 124°E, this suture does not seem to have moved much since the mid-Pliocene collision that emplaced the nappes on Timor. However, microearthquake data suggest some activity is continuing. 相似文献