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21.
Dmitry Kondrik Dmitry Pozdnyakov Lasse Pettersson 《International journal of remote sensing》2017,38(22):6179-6205
Making use of the OC CCI (Ocean Colour Climate Change Initiative) satellite data, and based on the developed both Emiliania huxleyi bloom contouring methodologies and binary masks, areas of coccolithophore growth were distinguished without supervision from locations of mass developments of other algae. On these grounds, and employing special processing algorithms, multi-year time series of variations in occurrence, surficial extent, and content of particulate inorganic carbon (PIC) within E. huxleyi blooming areas in the North, Norwegian, Greenland, Barents, and Bering Seas were obtained for the time period 1998–2013. Analysis of algorithmic processing of the OC CCI data permitted to reveal the spatio-temporal sequence of E. huxleyi blooming events in the above seas of the North Atlantic and Arctic Oceans. During the intra-annual cycle, E. huxleyi blooms advance from temperate to higher latitudes along the pathways of the Gulf Stream propagation to the north. Annually, the blooms arise in the vicinity of the Great Britain southern extremity, and further on move northward along the western coast of this Island Country, round it to eventually appear first in the North and Norwegian Seas (in early June), then in the Greenland Sea (in late June), and finally in the Barents Sea (in late July–early September). The regularities in dates of bloom outbreak and their duration are revealed. The bloom areas in the North Atlantic–Arctic water are the lowest in the Greenland Sea (10,000–30,000 km2) and by an order of magnitude higher in the Barents Sea. The same pattern holds for the total PIC content within E. huxleyi blooms: 400 t–14 kt in the Greenland Sea and about 0.35 Mt in the Barents Sea. In the Bering Sea, the temporal and spatial dynamics of E. huxleyi development proved to be highly irregular: before and after the 1997–2001 period of high intensity of this phenomenon, the blooms are sporadic, their extent and PIC production are either very low or insignificant. Regarding the range of E. huxleyi bloom areas in the Bering Sea during 1997–2001, it is rather similar to that of the Barents Sea. However, the PIC content in the Bering Sea, as compared to that in the Barents Sea, is higher by a factor of about two with maximum values reaching 0.4 Mt and, on one occasion (in 2001), even about 0.7 Mt. 相似文献
22.
Mette D. E. Jepsen Lasse L. Hildebrandt Victoria Birkedal Jørgen Kjems 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(15):1811-1817
Logic gates are devices that can perform logical operations by transforming a set of inputs into a predictable single detectable output. The hybridization properties, structure, and function of nucleic acids can be used to make DNA‐based logic gates. These devices are important modules in molecular computing and biosensing. The ideal logic gate system should provide a wide selection of logical operations, and be integrable in multiple copies into more complex structures. Here we show the successful construction of a small DNA‐based logic gate complex that produces fluorescent outputs corresponding to the operation of the six Boolean logic gates AND, NAND, OR, NOR, XOR, and XNOR. The logic gate complex is shown to work also when implemented in a three‐dimensional DNA origami box structure, where it controlled the position of the lid in a closed or open position. Implementation of multiple microRNA sensitive DNA locks on one DNA origami box structure enabled fuzzy logical operation that allows biosensing of complex molecular signals. Integrating logic gates with DNA origami systems opens a vast avenue to applications in the fields of nanomedicine for diagnostics and therapeutics. 相似文献
23.
24.
Rachel E. Pepper Emily E. Riley Matthieu Baron Thomas Hurot Lasse Tor Nielsen M. A. R. Koehl Thomas Kirboe Anders Andersen 《Journal of the Royal Society Interface》2021,18(175)
Microscopic sessile suspension feeders live attached to surfaces and, by consuming bacteria-sized prey and by being consumed, they form an important part of aquatic ecosystems. Their environmental impact is mediated by their feeding rate, which depends on a self-generated feeding current. The feeding rate has been hypothesized to be limited by recirculating eddies that cause the organisms to feed from water that is depleted of food particles. However, those results considered organisms in still water, while ambient flow is often present in their natural habitats. We show, using a point-force model, that even very slow ambient flow, with speed several orders of magnitude less than that of the self-generated feeding current, is sufficient to disrupt the eddies around perpendicular suspension feeders, providing a constant supply of food-rich water. However, the feeding rate decreases in external flow at a range of non-perpendicular orientations due to the formation of recirculation structures not seen in still water. We quantify the feeding flow and observe such recirculation experimentally for the suspension feeder Vorticella convallaria in external flows typical of streams and rivers. 相似文献
25.
P Vestergaard RW Licht A Brodersen NA Rasmussen H Christensen T Arngrim B Gr?nvall E Kristensen I Poulstrup R Wentzer Licht 《Canadian Metallurgical Quarterly》1998,98(4):310-315
Recently, the availability of 5-hydroxytryptamine-3 antagonists has provided better protection from chemotherapy-induced emesis. These drugs, in combination with dexamethasone, are more expensive but more cost-effective than the alternative antiemetic regimens in the prevention of acute emesis induced by high single dose and low and repeated doses of cisplatin and, probably, of acute emesis induced by moderately emetogenic chemotherapy. In the prevention of emesis induced by oral cyclophosphamide-methotrexate-fluorouracil and in the prevention of delayed emesis induced by cisplatin and moderately emetogenic chemotherapy, the most cost-effective choices are represented, respectively, by a combination of intravenous dexamethasone on day 1 and 8 plus 14-day oral metoclopramide (a combination of oral dexamethasone plus metoclopramide and oral dexamethasone alone). In all cases, the 5-hydroxytryptamine-3 antagonists should be used only in patients in whom the most cost-effective antiemetic regimens either fail or are not tolerated. 相似文献
26.
Further study of the gas temperature deviation in large-scale tangentially coal-fired boilers 总被引:1,自引:0,他引:1
Gas temperature deviation in upper furnace is an important but a less reported issue in large-scale tangentially fired boilers, since they endanger largely boilers operation. Simulations are conducted in this paper to study the deviation. Perfect agreement between the simulation results and key boiler design values and available site operation records indicates that the calculations are reliable. Based on the simulations, effect of some factors, including residual airflow swirling at furnace exit, super-heaters panels, coal particle trajectories and their combustion histories, on temperature deviations are studied in details. The most important cause and how it affects the temperature deviation are located. Two new methods, a nose on front-wall and re-arranged super-heater panels, are put forward unprecedentedly to alleviate the deviations. 相似文献
27.
Lasse M. Heikkinen Robert M. West Marko Vauhkonen 《International journal for numerical methods in engineering》2005,63(12):1719-1740
For many industrial processes the bulk volume fraction of one phase such as gas or solid can be of considerable importance. For this reason it is often controlled within certain limits and therefore is known at least vaguely. Tomographic imaging of volume fraction can provide very valuable information not only on the bulk volume fraction but also on the spatial distribution of the phase of interest. Prior information on the bulk volume fraction can assist in tomographic inversion, even if this information is not precise. In this paper we propose an electrical impedance tomography approach for imaging volume fraction distribution. A vague bulk volume fraction prior is utilized in the estimation. Two‐dimensional numerical examples are used to demonstrate the proposed method. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
28.
Johansson Lasse Koivo Heikki N. Peltomaa Arto S. 《Industrial Electronics, IEEE Transactions on》1984,(3):263-268
A design of an industrial microcomputer control system for a 1.6-MW boiler using solid fuel is presented. Instrumentation and control philosophies for the boiler are discussed. The microcomputer system is based on standard iSBC microcomputer boards. The software consists of a real-time operating system RXM/80 and application tasks. The designed control system saves fuel and gives a more reliable over-all operation. 相似文献
29.
C.P. Ferris P.J. Purcell A.W. Gordon T. Larsen M. Vestergaard 《Journal of dairy science》2018,101(8):7258-7273
This 2 × 2 factorial design experiment was conducted to compare the performance of spring-calving Holstein dairy cows (HOL, n = 34) with Swedish Red × Jersey/Holstein crossbred (SR × J/HOL, n = 34) dairy cows within low and medium concentrate input grassland-based dairy systems. The experiment commenced when cows calved and encompassed 1 full lactation. Cows were offered diets containing grass silage and concentrates [70:30 dry matter (DM) ratio, and 40:60 DM ratio, for low and medium, respectively] until turnout, grazed grass plus either 1.0 or 4.0 kg of concentrate/d during the grazing period (low and medium, respectively), and grass silage and concentrates (85:15 DM ratio, and 70:30 DM ratio, for low and medium, respectively) from rehousing and until drying off. No significant genotype × system interactions were present for any of the feed intake or full-lactation milk production data examined. Full-lactation concentrate DM intakes were 769 and 1,902 kg/cow for the low and medium systems, respectively, whereas HOL cows had a higher total DM intake than SR × J/HOL cows in early lactation, but not in late lactation. Although HOL cows had a higher lactation milk yield than SR × J/HOL cows, the latter produced milk with a higher fat and protein content, and thus fat plus protein yield was unaffected by genotype. Milk produced by the SR × J/HOL cows had a higher degree of saturation of fatty acids than milk produced by the HOL cows, and the somatic cell score of milk produced by the former was also higher. Throughout the lactation, HOL cows were on average 30 kg heavier than SR × J/HOL cows, whereas the SR × J/HOL cows had a higher body condition score than the HOL cows. Holstein cows had a higher incidence of mastitis and ovarian dysfunction that SR × J/HOL cows. 相似文献
30.
Effect of milk allowance on concentrate intake, ruminal environment, and ruminal development in milk-fed Holstein calves 总被引:1,自引:0,他引:1
The aim of the present experiment was to test the hypothesis that a barley-based concentrate would induce an acidic ruminal environment in young calves and that increased milk allowance would alleviate this condition. Eight Holstein calves ruminally cannulated at d 7 ± 1 of age were used to study the effect of variation in barley-based starter concentrate intake induced by 4 different milk allowances (3.10, 4.84, 6.60, and 8.34 kg of milk replacer/d; 123 g of dry matter/kg of milk) on the ruminal environment, blood variables, and fore-stomach development from wk 2 to 5 of age. Twelve ruminal fluid samples were collected during a weekly 24-h sampling in 4 consecutive weeks. Blood samples were collected by venipuncture between 1200 and 1300 h on ruminal sampling days. Rumen papillae development and visceral organ mass were recorded at slaughter. A linear treatment × week effect was observed for concentrate intake, with the calves fed the lowest milk allowance having the fastest increase in concentrate intake whereby these calves reached the same ME intake in wk 5 compared with calves with the highest milk allowance. Effects on ruminal variables were dominated by week of sampling, with minor differences among treatments. Ruminal pH was below 5.5 for 5 to 13 h/d and all calves with concentrate intake above 20 g of dry matter/d were observed to have a daily ruminal pH minimum at pH 5.5 or lower. The ruminal concentration of total volatile fatty acids (VFA) increased from 71 to 133 ± 9 mmol/L in wk 2 to 5 and was characterized by a relatively high molar proportion of propionate, increasing from 34 to 40 mol/100 mol of VFA in wk 2 to 5. In addition, the presence of ethanol and propanol as well as numerous VFA esters points to a ruminal environment with a relatively high hydrogen pressure. Plasma glucose and insulin responded to the highest milk allowance in wk 2 to 4. Plasma VFA and ketone bodies increased with the lowest milk allowance in wk 4 to 5. At slaughter, empty wet weights of the rumen + reticulum and omasum as well as mass of digesta in these compartments were found to decrease linearly and perirenal fat was found to increase linearly with milk allowance, indicating that the milk allowance changed the body composition of the calves. Lengths of ruminal papillae in the atrium and ventral ruminal sac were not affected by treatment. We concluded that the ruminal environment of young calves fed a barley-based starter concentrate was characterized by a low ruminal pH and high VFA concentration regardless of the milk allowance. 相似文献