A Temperature-Dependent Growth Equation for Larval Chub Mackerel (Scomber japonicus)     

Go  Seonggil  Lee  Kyunghwan  Jung  Sukgeun 《Ocean Science Journal》2020,55(1):157-164

Ocean Science Journal - Chub mackerel are commercially one of the most important species in the western North Pacific. Variations in water temperature and growth during the early life stages are...  相似文献   

Estimation of global lightning activity and observations of atmospheric electric field     

Marek Gołkowski  Marek Kubicki  Morris Cohen  Andrzej Kułak  Umran S. Inan 《Acta Geophysica》2011,59(1):183-204

Variations in the global atmospheric electric circuit are investigated using a wide range of globally spaced instruments observing VLF (∼10 kHz) waves, ELF (∼300 Hz) waves, Schumann resonances (4–60 Hz), and the atmospheric fair weather electric field. For the ELF/VLF observations, propagation effects are accounted for in a novel approach using established monthly averages of lightning location provided by the Lightning Image Sensor (LIS) and applying known frequency specific attenuation parameters for daytime/nighttime ELF/VLF propagation. Schumann resonances are analyzed using decomposition into propagating and standing waves in the Earth-ionosphere waveguide. Derived lightning activity is compared to existing global lightning detection networks and fair weather field observations. The results suggest that characteristics of lightning discharges vary by region and may have diverse effects upon the ionospheric potential.  相似文献   

Lake‐level changes in central Patagonia (Argentina): crossing environmental thresholds for Lateglacial and Holocene human occupation     

Daniel Ariztegui  Adrian Gilli  Flavio S. Anselmetti  Rafael A. Goñi  Juan B. Belardi  Silvana Espinosa 《第四纪科学杂志》2010,25(7):1092-1099

The role and extent of climate as a cause of the expansion and decline of human cultures is still debatable. It is clear, however, that human–environment interactions are enhanced and interplay more closely in climatically sensitive areas such as around hydrologically closed basins. Lago Cardiel is located at 49° S in the very arid rain shadow east of the Andes, providing an exceptionally receptive system to changes in hydrological balance. Results of a geophysical survey combined with sedimentological and geochemical studies provide a continuous Lateglacial–Holocene record of substantial water‐level changes. These variations, combined with archaeological results from the catchment area, offer a unique possibility to explore the pattern of peopling within this remote area of the globe and its possible relation to climate change. Human occupation in Patagonia is well documented towards the Andes throughout the entire Holocene. Archaeological data from the Lago Cardiel basin, however, show an apparent lack of human activity during the first part of this period, which coincides with well‐constrained high lake levels. Our results show an intriguing coincidence between low lake level and increasing human occupation, suggesting that the Lago Cardiel basin has focused human use during intervals with relatively lower effective moisture such as during the Late Pleistocene, but its evidence may have been submerged. This interpretation is confirmed by archaeological remains from Lago Strobel, another perennial lake with a comparable catchment located in the same climatic region and thus sharing the same climatic history as Lago Cardiel. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Observation of Mercury's sodium exosphere during the transit on November 9, 2006     

Ichiro Yoshikawa  Junya Ono  Go Murakami  Shingo Kameda 《Planetary and Space Science》2008,56(13):1676-1680

A rare, but normal, astronomical event occurred on November 9th 2006 (JST) as Mercury passed in front of the Sun from the perspective of the Earth. The abundance of the sodium vapor above the planet limb was observed by detecting an excess absorption in the solar sodium line D₁ during this event. The observation was performed with a 10-m spectrograph of Czerny-Turnar system at Domeless Solar Tower Telescope at the Hida Observatory in Japan. The excess absorption was red-shifted by 10 pm relative to the solar line, and was measured at the dawnside (eastside) and duskside (westside) of Mercury. Between the dawn and dusksides, an asymmetry of total sodium abundance was clearly identified. At the dawnside, the total sodium column density was 6.1×10¹⁰ Na atoms/cm², while it was 4.1×10¹⁰ Na atoms/cm² at the duskside. The investigation of dawn-dusk asymmetry of the sodium exosphere of Mercury is a clue to understand the release mechanism of sodium from the surface rock. Our result suggests that a thermal desorption is a main source process for sodium vapor in the vicinity of Mercury.  相似文献   

3D GPR measurements for archaeological application with interpretation aided by numerical modelling     

Tomisław Gołębiowski 《Acta Geophysica》2006,54(4):413-429

The paper presents the results of georadar investigations carried out in the area of the monastery at Tyniec near Cracow for archaeological purposes. The georadar profiles were designed on the abbey courtyard in a regular grid, which covered the area of the buildings that currently do not exist. The aim of the measurements was to produce a 3D visualization of former buildings’ foundation. The results of the geophysical measurements were correlated with the information obtained from archaeological investigations. The georadar surveys confirmed the location of foundations documented by archeologists and new underground structures were discovered. To aid the interpretation, numerical modelling of the electromagnetic wave field was performed. Computer modelling allowed to determine the kind and condition of underground structures.  相似文献   

据地貌声图判读研究海底地貌和底质类型   总被引：1，自引：0，他引：1       下载免费PDF全文

郭旭东  冯文科 《地质科学》1978,13(4):373-382

侧向扫描声呐这项新技术方法及其在海洋地质调查中的应用问题,最近作者已作过介绍。1975年,我们应用侧向扫描声呐(侧扫声呐)、精密回声探测、海底采样等方法,对中国南海某浅海区进行了海底地质调查,了解海底地貌和底质类型及其包括砂矿等的分布。  相似文献   

Seasonal patterns of nitrification and denitrification in a natural and a restored salt marsh     

Suzanne P. Thompson  Hans W. Paerl  Malia C. Go 《Estuaries and Coasts》1995,18(2):399-408

Seasonal patterns of microbially-mediated nitrogen cycling via the nitrification-denitrification pathway were compared between a natural and a restored salt marsh. Sedimentary denitrification rates, measured with a modification of the acetylene block technique, were approximately 44 times greater in the natural marsh relative to an adjacent transplanted marsh. Nitrification rates were similar at both sites. The difference in denitrification rates was attributed to oxygen inhibition at low tide and tidal flushing of porewater nutrients at high tide in the coarse sediments of the restored marsh. Denitrification was positively correlated with nitrification throughout the year in the natural marsh with a seasonal fall peak in denitrification corresponding to a maximum in porewater ammonia concentration. A weak correlation existed between the two processes in the restored marsh, where nitrification rates exceeded denitrification rates by a factor of 20. Transplanted marsh denitrification rates exhibited a spring peak, corresponding to elevated porewater ammonia concentrations. Our findings demonstrate functional differences in microbial nitrogen dynamics of a young (0–3 yr) restored marsh relative to a mature (>50 yr) salt-marsh system. *** DIRECT SUPPORT *** A01BY070 00008  相似文献   

Normalization algorithms of Hamiltonian near an equilibrium point     

Andrzej J. Maciejewski  Krzysztof Goździewski 《Astrophysics and Space Science》1991,179(1):1-11

Algorithms of linear and nonlinear normalization of a Hamiltonian system near an equilibrium point are described. They were applied to determination of stability libration point in photogravitational restricted problem and to refinement of periodic orbits in the restricted three body problem.  相似文献   

浅地层剖面仪在海岸工程上的应用   总被引：11，自引：0，他引：11  

张金城  蔡爱智  郭一飞  石谦 《海洋工程》1995,(2)

现代海湾的迅速沉积其物源来自河流入海泥量的猛增。浅地层剖面仪以灵敏度和分辨率高，连续性好且能快速地探测不同沉积层的特征及其分布。在海湾工程中，无论是航道整治还是码头选址和施工勘探都可以应用浅地层剖面仪作为先头“侦察兵”而获得良好的结果。其优越性是节省投资、加快建设进度，又提高勘探质量，帮助设计和施工部门快捷地解决那些需要解决的而常规方法又难以完成的问题。  相似文献   

Water lily (<Emphasis Type="Italic">Nymphaea</Emphasis> sp.): an alternative organic amendment for treatment of hydrocarbon-contaminated soil by chemical–biological stabilization     

V. I. Domínguez-Rodríguez  R. H. Adams-Schroeder  J. A. Goñi-Arévalo  I. López-Vidal 《International Journal of Environmental Science and Technology》2018,15(9):1851-1858

The chemical–biological stabilization technology has been employed in several successful studies using sugarcane cachasse as the organic amendment. However, in some petroleum-producing areas, there are no sugar mills nearby (which is the source of this material), and the cost of transport to the contaminated site is prohibitive. Therefore, water lily, which is considered a weedy plant in many tropical and subtropical areas, was evaluated as an alternative. In 3-month experiment, water lily was compared (with and without addition of molasses) with cachasse for the treatment of clayey sediment contaminated with > 6% extra-heavy crude oil. All treatments resulted in a reduction in the hydrocarbon concentration of 15–23%, without significant differences (P > 0.05). During this process, the pH was reduced to the 7–7.5 range and water repellency (molarity ethanol drop) to 3.5–3.6 M. Also, field capacity increased to 36.3–38.5% humidity, establishing adequate conditions for the development of vegetation at this site. Likewise, toxicity was reduced to practically null (Vibrio fischeri bioassay), and hydrocarbons in leachates were reduced to 3.4–4.3 mg/l, conditions adequate for the protection of groundwater and human health in rural areas. This study confirms that water lily is an adequate substitute for the application of this treatment method for hydrocarbon-contaminated sites that are far from sugar production areas.  相似文献