首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 498 毫秒
1.
脆嫩–厚成期海带物质成分变化分析研究   总被引:1,自引:0,他引:1  
采用国家规定的标准方法,分别测定了脆嫩-厚成期(1~5月份)荣成地区养殖海带体内9种物质(蛋白、脂肪、粗纤维、粗灰分、碘、磷、钙、铁和锌)含量,系统分析了各物质成分含量变化规律,以及各成分与海水温度的关联性。分析表明,不同物质质量分数最高值出现时间不同,其中蛋白质和粗灰分质量分数最高值出现在1月份,脂肪、磷和锌出现在2月份,碘和铁出现在3月份,粗纤维和钙出现在5月份。同时,1~5月份各种物质质量分数变化规律也不相同,蛋白质、粗灰分、磷和锌的质量分数呈现下降趋势,粗纤维、钙的质量分数呈上升趋势,而碘和铁的质量分数变化不稳定。蛋白质、脂肪、粗纤维、粗灰分、磷和锌含量变化与温度有显著关联性。  相似文献   

2.
采用傅里叶变换近红外(FT-NIR)光谱技术,以94份具有代表性的长牡蛎鲜样组织样本的近红外(NIR)数据和其对应的化学真实值数据为基础,研究了NIR技术预测长牡蛎鲜样组织中水分、糖原、总蛋白质、总脂肪、锌、硒、牛磺酸和灰分8种成分含量的可行性,通过偏最小二乘回归法(PLS)建立了以上8种成分的NIR分析模型,并对模型进行了交互验证和外部验证。结果显示:该实验所建立的长牡蛎鲜样组织肉质性状8项主要指标中水分、糖原和总蛋白质3种成分的NIR模型具有良好的准确性和预测能力,建模集相关系数(RC)为0.9625—0.9902,交互验证相关系数(RCV)为0.9342—0.9863,外部验证的相关系数(REV)为0.9734—0.9915;但总脂肪、锌、硒、牛磺酸和灰分含量的建模效果不佳。实验结果表明,可以运用NIR技术快速、大批量地分析长牡蛎鲜样组织中的水分、糖原和总蛋白质3种成分含量;分析过程无需使用化学试剂,实验成本低,且对环境无污染。长牡蛎NIR多种成分含量模型的建立,对开展长牡蛎肉质分析、肉质性状选育、育种世代的鉴定及种质资源评价都有非常重要的意义。  相似文献   

3.
The method for determining the dynamic characteristics of the atmosphere using the data of sounding from geostationary meteorological satellites developed by the authors and based on using inhomogeneities of the conservative admixture concentration field as tracers and on applying the correlation extreme algorithms is described in detail. The accuracies in calculating the horizontal wind velocity vector (V) and coefficient of horizontal mesoscale turbulent diffusion (K d ) are estimated on the basis of processing the data of sounding the atmosphere with a SEVIRI (Spinning Enhanced Visible and Infrared Imager) radiometer on the Meteosat-8 and Meteosat-9 European geostationary meteorological satellites in the water vapor channels centered at 6.2 and 7.3 μm and on comparing the results with the data of independent observations and theoretical models. It is indicated that the accuracy in calculating V using the developed method almost coincides with the accuracy of the commonly used foreign methods. In contrast to the methods applied abroad, the developed method makes it possible to determine not only the wind velocity vector field but also the coefficient of mesoscale turbulent diffusion and vorticity on one scale of air mass motion.  相似文献   

4.
Abstract

Two mathematical models of different complexity were used to study transverse dispersion and surface heat transfer in the lower Waikato River. A simple analytical streamtube model (HPLUME) gave adequate temperature predictions in a reach where the channel was fairly regular but performed poorly where there were extensive shallows. In the latter reach, a two‐dimensional numerical model (SYSTEM21) gave good temperature and flow predictions once properly calibrated. Model calibration proved to be difficult in the Waikato River because the natural river temperature varied significantly along the channel. A search method was developed to estimate both the transverse dispersion and surface heat exchange coefficients from measured plume temperature profiles based on the observation that transverse variations in natural temperature were small. This method was used to calibrate SYSTEM21 in two separate reaches. Coefficient estimates were sensitive to measurement errors and slight departures in homogeneity of natural temperature and it would be desirable to corroborate the estimates of Ez using dye tests. In the upper reach, the average transverse dispersion coefficient was Ez/hu? = 1 which is high but within the range of published values. A sharp bend and buoyant spreading contributed to the high Ez value. Ez increased with river flow because both h and u? increase with flow. In the lower reach, Ez/hu? = 0.1 which is lower than expected but islands may have affected the model calibration. The surface heat exchange coefficient averaged K = 84–167 W m?2 s?1 °C?1 which falls within the range of published values. No significant relationship could be found between surface heat exchange coefficient and meteorological variables.  相似文献   

5.
The Aral Sea is an important water area both for monitoring and oceanological studies, because its salinity and salt composition strongly differ from the oceanic. We offer a semiempiric calculation method of electric conductivity and the coefficient of its temperature dependence k judging from the ionic composition of water. The properties of the solution are considered as the sum of properties of seven binary salts taken based on the ionic composition of the solution. The MgSO4 concentration is thought to be the highest possible, which makes the salt concentration nearly unambiguous. In a salinity range of 46–120‰ and temperature range of 5–25°C (2002–2009), the standard deviation of the calculated and measured electric conductivity was 2.9%. To refine the calculation of salinity from electric conductivity measurements using the “oceanic” formula, we suggest its preliminary reduction to a constant temperature (20°C) using the measured or calculated coefficient k.  相似文献   

6.
Oxygen consumption rates (V?o2) in the grass shrimp Palaemonetes pugio were determined after a 32 day exposure to fluctuating temperatures (FT) (18–22°C) and/or dimethylnaphthalene (DMN)-contaminated food (0·24 μg DMN g wet wt?1) and again after a 16 day recovery period of stable temperatures (20°C) and uncontaminated food. Ingestion of DMN-contaminated food for 32 days resulted in elevated V?>o2 in shrimp exposed to declining oxygen concentrations. After the 32 day exposure period, FT had no significant effect on V?o2 at 15, 20 and 25°C, tissue V?o2 and V?o2 in declining oxygen. Hemolymph copper concentrations were significantly depressed in shrimp exposed to DMN-contaminated food. After the 16 day recovery period, shrimp from the FT regime exhibited depressed V?o2 when exposed to 25°C but not to 15°C. These depressed respiratory rates were offset by the stimulatory effect of DMN-contaminated food.These respiration studies were generally unproductive in explaining the previously reported effects of FT and DMN-contaminated food on the survival of P. pugio under hypoxic conditions.  相似文献   

7.
Summary

Reids Rise is a remnant of a marine sand body that accumulated in the inner neritic zone of the continental shelf south‐west of Westport during the Last Interglacial. The sand body is notable for its spectacular sedimentary structures and consists of an upper unit that is characterised by trough cross‐lamination, locally forming mesoscopic ridges, and a lower unit that is characterised by horizontal lamination. The sand body is underlain by gravels of probable alluvial origin.

The trough cross‐laminated sets of the upper unit dip off near‐symmetrical ridges that probably formed as subaqueous bars. The dip azimuths of the cross‐laminae have a polymodal distribution with two bimodal maxima, one almost perpendicular to, and the second roughly parallel to the shoreline formed during the Last Interglacial. Magnitude of dip varies from horizontal to over 40°.

The sediment is clean, fine sand composed predominantly of angular grains. Sample to sample variation in grain size statistical parameters is small. The most notable feature is the extremely good sorting of the sand. Inclusive graphic standard deviation values range over 0.17–0.24? with 0.20? the modal value.

The mineralogy of the sand points to two main source areas, the Alpine metamorphic rocks to the south and south‐east, and the plutonic rocks of the Paparoa Range immediately east and south‐east of the study area.

The stratigraphic sequence is interpreted as being the product of deposition in a high energy, wave‐, tidal‐current‐, and longshore‐current‐dominated shallow neritic zone on an open coast during a transgressive cycle.  相似文献   

8.
ABSTRACT

In this paper, a series of mini-drum centrifuge experiments on motion of submarine debris flow, which are able to correctly reproduce the self-weight stresses and gravity-dependent processes, are presented. These tests were performed using artificial submarine clay with high water content, from 93 to 149%. The extremely low shear strength made the debris material behave as idealistic lubricating material when it was deposited, resulting in a linear relationship between water content and runout distance of strongly coherent debris flow. On the other hand, the dilation of the flow body and hydroplaning was observed for weakly coherent debris flow, which further increased the mobility of flow body. A densimetric Froude number Frd was used to indicate the threshold of hydroplaning, which occurs if the Frd is greater than 0.2. Finally, two simple analytical models based on prototype debris flow under 1?g condition was used to validate the experiment results, which further prove the effects of soft marine clay on the high mobility of submarine debris flow. On the other hand, when the water content exceeded 120%, the experiment results deviated from the analytical solution due to the effects of hydroplaning.  相似文献   

9.
Abstract

The age of pufferfish Uranostoma richei (Freminville) in Lyttelton Harbour, South Island, New Zealand is described from analyses of length‐frequency distributions and growth zones in otoliths. Length‐frequency analysis is adequate only for aging smaller fish. The validity of using growth zones in otoliths is checked by examining the pattern and time of zone formation. Length‐weight relationships are established and growth rates calculated. Compared with males, females grow faster (2.4cm·y?1; 2.1 for males), attain a larger size (to 18 cm and 120 g; 12 cm and 40 g for males) and live longer (to 7 y; 5 for males).  相似文献   

10.
Abstract

Sands and silty sands are the predominant surficial soils of continental shelves. Cohesive fine‐grained soils are typical off the mouths of large rivers, near bays and estuaries, and in basins located on the shelf. The stratigraphy of shelf soils is very poorly known for most engineering purposes, except in the vicinity of the Mississippi Delta.

Vibratory coring is the most common method of sampling shelf sands to depths of about 13 m; greater soil depths are sampled by borings often using drilling and wireline sampling tools. Employment of self‐contained or wireline static cone penetrometers to obtain in situ measurements of sands has not been as common in the United States as in Europe. Dynamic piston corers are the most common samplers in cohesive soils, but rotary and hydraulically activated incremental corers are becoming available for marine use. Self‐contained or wireline vane shear devices and static cone penetrometers are used for the in situ testing of cohesive soils, and the latter device is also used for cohesionless soils. Dynamic cone penetrometers have been developed and have had limited experimental use at sea. In situ electrical resistivity and nuclear‐transmission and backscatter probes have been used in cohesive soils to obtain bulk‐density and water‐content measurements and for stratigraphic correlation. Acoustical properties of cohesive and cohesionless soils have been measured by in situ probes and have been estimated from results of geophysical surveys made on ships that are under way.

Environmental hazards to the foundations of offshore structures include earthquakes, wave‐induced loading and scour, and burrowing animals. Reported bottom‐current velocities on the United States continental shelf appear to have maximums of about 0.5 m/s under fair‐weather conditions and greater than about 5 m/s under hurricane conditions. Cyclical loading of the seafloor induced by storm waves appears to be a major hazard to soil stability in some areas.

A representative sample of the widely scattered engineering and scientific literature of continental shelf marine geotechnics and geotechnically related subjects has been made to aid marine geologists, geotechnologists, and other specialists.  相似文献   

11.
Abstract

The Canadian program for obtaining hydrographic data by aerial methods consists of merging laser bathymeter data with photogrammetric depth data. The main deficiency of the photogrammetric approach for bathymetric measurements is that incomplete stereomodels can occur in areas where little or no land appears. This problem is overcome by using an inertial navigation system (INS) hardmounted to the aerial camera to provide the orientation parameters of position and attitude for each photograph. In order to meet the high accuracy requirement, the INS and other complementary navigation data are processed through a post‐mission track recovery software package. The photogrammetric depths are improved further by merging them with the waterline height information and the laser bathymeter depths using a least‐squares adjustment algorithm. The photogrammetric compilation, depth measurements, shoreline plots, and laser bathymeter integration is done in an analytical stereoplotter. This instrument provides an on‐line refraction correction necessary because of the two‐media mode of operation. Results of a recent pilot project indicate that the integrated system is capable of obtaining depth measurements that agree with echo sounder depth measurements to a precision of .65 m (RMS), and that it can position measured depths to a precision of .74 m (RMS) relative to local control.  相似文献   

12.
山东省荣成市近岸海域褐藻资源丰富,为系统了解鼠尾藻(Sargassum thunbergii)、海黍子(Saragassumkjellmaniamum)、铜藻(Sargassum horneri)和羊栖菜(Sargassum fusiforme)四种褐藻的营养价值,通过测定其一般营养成分(水分、粗蛋白、粗脂肪、灰分、碳水化合物),氨基酸组成、脂肪酸组成、重金属含量等,对其营养价值进行分析及评价。结果显示:四种海藻一般营养成分以碳水化合物为主,其次为灰分,蛋白质和脂肪。氨基酸种类齐全且人体必需氨基酸质量分数较高,鼠尾藻、海黍子、铜藻和羊栖菜的必需氨基酸占氨基酸总量的比例分别为32.83%、37.35%、30.82%和40.55%,接近FAO/WHO的理想模式;呈味氨基酸占氨基酸总量比例分别为56.38%、51.67%、49.78%和45.07%,使得具有较好的风味,可作为开发海藻调味料的原料;必需氨基酸指数(EAAI)分别为85、71.79、73.38和95.80;脂肪含量低,脂肪酸含量依次为饱和脂肪酸>多不饱和脂肪酸>单不饱和脂肪酸,四种褐藻n-3脂肪酸和n-6脂肪酸的总量...  相似文献   

13.
本文应用正交设计法试验了中国对虾(Penaeus oricntalis)配饵中蛋白质、糖、纤维素、脂肪的适宜含量及其日需量。体重为2.87—3.44g的幼虾,其配合饵料中各营养素的适宜含量为:粗蛋白44%、粗脂肪4%、糖26%、粗纤维4.5%。粗脂肪含量对蛋白质的利用有着明显的制约作用。在本试验条件下,每kg对虾日需蛋白质25.9强、糖15.34g、粗纤维2.66g、粗脂肪2.36g。日投饵率为虾体重的5.9%,配饵总能为13.23×10~6J/Kg,c/p为71.8。  相似文献   

14.
ABSTRACT

Recruiting King George whiting Sillaginodes punctatus were studied to assess the potential for food competition with permanent resident fish species in a nursery habitat. Marine migrant post larval S. punctatus (<60?mm TL) consumed primarily harpacticoid copepods and had high (>0.6) diet overlap with permanent resident fish species Favonigobius leteralis and Stigmatopora nigra. Food electivity index indicated that S. punctatus juveniles preferred harpacticoid copepods and amphipods, while juvenile Heteroclinus adelaide and Gymnapistes marmoratus migrating to the nursery habitat targeted larger prey such as amphipods. Preference for larger prey by H. adelaide and G. marmoratus species coupled with differences in prey composition in the stomach was due to mouth size and feeding habits, resulting in different food preferences to S. punctatus. The whiting showed an ontogenetic shift in diet with early settlers (>60?mm TL) consuming less copepods and more amphipods, while previous year recruits (>120?mm TL) consumed polychaete worms. This study indicates that competition for food resources between the new recruiting S. punctatus juveniles and permanent resident juveniles is reduced through differences in temporal and spatial feeding behaviours, mouth morphology, and ontogenetic shift in prey consumption.  相似文献   

15.
Edwardsiella tarda is one of the most important emerging pathogens in the global aquaculture industries. As such, an accurate diagnosis and quantitative analytical methods are urgently needed for this bacterium. In this study, primers and a TaqMan probe specific to the conservative sequences of the 16S rRNA gene of E. tarda were designed. The concentration of primers and TaqMan probe were optimized to 200 nmol/L and 120 nmol/L, respectively. The detection sensitivity of the FQ-PCR assay was determined to be as low as five copies of the target sequence per reaction using the pGEM-16S rDNA recombinant plasmid as a template, which was 100 times more sensitive than conventional PCR. A standard curve by plotting the threshold cycle values (y) against the common logarithmic copies (log10 nc as x; nc is copy number) of pGEM-16S rDNA was generated. The results of intra-and inter-assay variability tests demonstrate that the established FQ-PCR method was highly reproducible. The assay was specific for E. tarda as it showed that there was no cross-reactivity to eight additional bacterial pathogen strains in aquaculture. Thus, the FQ-PCR assay has the potential for diagnostic purposes and for other applications, especially for the rapid detection and quantification of low-grade E. tarda infections.  相似文献   

16.
Abstract

Intra and inter-annual variations in the sea ice thickness are highly sensitive indicators of climatic variations undergoing in the earth’s atmosphere and oceans. This paper describes the method of estimating sea ice thickness using radar waveforms data acquired by SARAL/Altika mission during its drifting orbit phase from July 2016 onwards yielding spatially dense data coverage. Based on statistical analysis of return echoes, classification of the surface has been carried out in three different types, viz. floe, lead and mixed. Time delay correction methods were suitably selected and implemented to make corrections in altimetric range measurements and thereby freeboard. By assuming hydrostatic equilibrium, freeboard data were converted into sea ice thickness. Results show that sea ice thickness varies from 4 to 5?m near ice shelves and 1 to 2.5?m in the marginal sea ice regions. Freeboard and sea ice thickness estimates were also validated using NASA’s Operation Ice Bridge (OIB) datasets. Freeboard measurements show very high correlation (0.97) having RMSE of 0.13. Overestimation of approximately 1–2?m observed in the sea ice thickness, which could be attributed to distance between AltiKa footprint and OIB locations. Moreover, sensitivity analysis shows that snow depth and snow density over sea ice play crucial role in the estimation of sea ice thickness.  相似文献   

17.
本文通过乘法散射校正(multiplicative scattering correction MSC)、一阶求导(1st Derivative,Db1)和Norris平滑等傅里叶变换近红外光谱定量分析数学模型,用交叉验证法确定了最优化建模参数,构建了牡蛎中氨基酸的快速定量测定方法。结果表明,牡蛎近红外光谱与氨基酸含量化学计量学拟合,线性相关系数为0.9860,交叉验证后线性相关系数为0.9794,对牡蛎样品进行检测,结果与传统的氨基酸分析仪的测试结果相比,相对误差小于2.5%,方法的精密度(RSD)小于1.0%,本文建立的傅里叶变换近红外光谱法定量分析牡蛎中氨基酸具有快速、准确、操作简便等特点,测定重复性优于氨基酸分析仪法。  相似文献   

18.
昒sually, the stepwise regression method is used to select the forecasting factors in the most forecasting problems and the double correlation coefficient is used as a standard for the judge ment of the forecasting function. In fact, it cannot be decided whether the forecasting function is to be adopted or not only according to whether the double correlation coefficient is large or small. Here, we used the freedom adjusting method of the double correlation coefficient to study the season forecasting and used the method to select the factors for the fishing season forecasting function of the Spanish Mackerel (Scomberomorus) at the estuary of the Changjiang River. The test result of reforecasting is satisfactory and the greatest error is only two days as compared with the real fishing season. The forecasting result of the fishing season is also satisfactory.  相似文献   

19.
The possibility of using the pyrene metabolite 1-hydroxypyrene as a biomarker of polycyclic aromatic hydrocarbons (PAHs) exposure was investigated by exposure of the marine polychaete Nereis diversicolor to several PAHs in the laboratory. Animals were exposed to pyrene alone and to five different PAHs – phenanthrene, anthracene, pyrene, benzo[a]pyrene and benzo[k]flouranthene. After five days of exposure the concentrations of parent PAHs and 1-hydroxypyrene were identified using three different analytical methods, high-performance liquid chromatography with fluorescence detection (HPLC/F), synchronous fluorescence spectroscopy (SFS) and gas chromatography with mass spectrometric detection (GC/MS). The SFS measurements of 1-hydroxypyrene were validated by the more sensitive method HPLC/F. The positive correlation between total PAHs and 1-hydroxypyrene concentrations in the polychaete tissues observed in experiments, suggests the feasibility of 1-hydroxypyrene as a suitable biomarker for total PAH exposure assessment. Furthermore, the possibility of employment of the simple and rapid SFS method instead of HPLC/F for biomarker analysis has been confirmed by the positive and significant correlation between results achieved by these two analytical methods.  相似文献   

20.
Reproductive aspects of the golden ling, Genypterus blacodes, from the southern Chilean fishery are presented. Gonad samples were obtained from commercially caught fish between September 1999 and October 2000. Stage of sexual maturity, gonadosomatic index (GSI), and size of females at 50% maturation determined by logistic methods and by plotting the mean GSI by total length, are presented for both years. Batch fecundity was calculated from subsampling mature ovaries containing oocytes in advanced stages of maturity. Changes in GSI and monthly diameters of oocytes showed that ling had a spawning season which extended between August and November. The sizes at first maturity in 1999 and 2000 were 86.6 and 84.8 cm total length (TL), respectively, using the logistic model, and 84 cm for both years using the mean GSI‐size plotting method. The mean batch fecundity was 333 330 oocytes per individual for fish sized 85–120 cm TL. Fecundity increased with increasing weight and total length.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号