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High Growth Rates (high + growth_rate)
Selected AbstractsNITROGEN ENRICHMENT OF PORPHYRA PERFORATA THROUGH HIGH DOSE PULSE FERTILIZATIONJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Zertuche-González, J. A1., Chanes-Miranda L2., Carmona, R3., Kraemer G4., Chopin T.5 & Yarish, C3 1Universidad Autonoma de Baja California, Instituto de Investigaciones Oceanologicas, PO Box #453, C.P. 22830, Ensenada, Baja California, Mexico. 2CBTIS-41, Km 115 Carretera Transpeninsular, Ensenada, BC Mexico. 3University of Connecticut, Department of Ecology and Evolutionary Biology, 1 University Place, Stamford, CT, 06901-2315, USA. 4State University of New York, Purchase College, Div. of Nat. Sciences, Purchase, NY, 10577, USA. 5University of New Brunswick, Centre for Coastal Studies and Aquaculture and Centre for Environmental and Molecular Algal Research, P.O. Box 5050, Saint John, New Brunswick, E2L 4L5, Canada Porphyra perforata is a highly preferred seaweed used as fodder in abalone culturing due to its relatively high nutritional value. High growth rates of abalone, particularly in the early stages, are suspected to be due the high protein-aminoacid and low water content of the Porphyra. Also, high NO3 content may be important to improve the bacterial flora in the animals, which in turn may favor more efficient digestion. Changes in the composition of Porphyra, however, can occur rapidly due to environmental conditions decreasing the nutritional value of the plant. Short term N pulse fertilization were performed on P. perforata in order to evaluate the feasibility to increase its nutritional value. Enrichment was performed under low light conditions (<5 ,E m -2 s -1) to inhibit growth and promote higher N enrichment per unit of biomass. Tissue N in the form of NO3, NH4 and total organic N were measured, after 3,6,12 and 24 hrs, in tissue exposed to 500 ,M of N. Results indicated a rapid N tissue enrichment particularly in the form of NO3. Nitrate accumulation occurs continuously, up to 24 hrs. Total organic N is maximum after 12 hrs and tends to decrease after that. Fertilization with NH4 promotes NO3 accumulation. These results suggest the feasibility to improve the nutritional value of P. perforata by short-term pulse fertilization. The capacity of this species to uptake NH4 under low light conditions (similar to those use in abalone culturing) makes it also ideal for integrated aquaculture. [source] Flux growth of straw-like rutile monocrystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2008A. Bloise Abstract Millimetric straw-like rutile monocrystals were grown by the flux growth technique. A suitable mixture of flux (MoO3, V2O5, Li2CO3) and amorphous TiO2 gel was slowly cooled down to 750°C from 1250°C or 1350°C. The best yields of straw-like rutile were obtained with a nutrient/flux ratio and a cooling rate in the range 0.015-0.006 and 1.8-1.9 K h -1, respectively. The hollowed crystals were characterized by powder and single-crystal X-ray diffraction, scanning electron microscopy, microthermometry, and µ-Raman spectroscopy. As for skeletal crystal, the formation of axial canals in rutile is attributed to a lack of nutrient due to the viscosity of the melt and the high growth rate along [001]. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] In Vitro Characteristics of Surface-Modified Biphasic Calcium Phosphate/Poly(L -Lactide) BiocompositeADVANCED ENGINEERING MATERIALS, Issue 4 2010Weizhong Yang Abstract Surface-modified biphasic calcium phosphate (BCP)/poly(L -lactide) (PLLA) biocomposite is shown to have improved microstructure and mechanical properties compared to the unmodified system. In vitro biodegradation and bioactivity of the composite are investigated in simulate body fluid for up to four weeks. Weight changes of the samples and the pH changes of the SBF are recorded. Surface properties of the composite after immersion are characterized by XRD, SEM and EDX analyses. Cyto-compatibility was determined by MTT assay with L929 mouse fibroblasts. The difference of the degradation behavior between modified BCP/PLLA and the reference unmodified composite are investigated, and mBCP/PLLA composite is proved to be a better as a scaffold material. The surface formed bio-apatite layer after immersion shows the excellent bioactivity of the mBCP/PLLA composite. L929 cells show a high growth rate and proliferation, demonstrating the good cytocompatibility of mBCP/PLLA composite. [source] Carrying capacity and survival strategy for the Pacific bluefin tuna, Thunnus orientalis, in the Western PacificFISHERIES OCEANOGRAPHY, Issue 2 2006YASUO MATSUKAWA Abstract The carrying capacity for the Pacific bluefin tuna at each life stage is estimated and its survival strategy is examined numerically, using a new method to define the hypothetical capacity, the standard population, and the search volumes that are necessary and are feasible for the tuna. The carrying capacity for the adult is estimated at 1,2 × 106 individuals, which corresponds with 5,10% of the hypothetical capacity and is comparable with the maximum levels of the southern and the Atlantic bluefin tuna populations. It is hypothesized semiquantitatively that the migration at each life stage and the remarkable decrement of growth at 120 days and about 40 cm occur as an evolutionary response to population excess over the carrying capacity. It is also hypothesized semiquantitatively that the early larvae have minimal food available in the Subtropical Water and develop the predatory morphology, high growth rate, and high mobility, however, at the expense of a high mortality as an evolutionary response to the tuna spawning in the Subtropical Water. This method may be an available tool to not only investigate the carrying capacity and survival strategy of a specific fish species, but also predict when and in how much abundance the fish species occurs in a specific area of its habitat. [source] Responses of shoot growth and survival to water stress gradient in diploid and tetraploid populations of Lolium multiflorum and L. perenneGRASSLAND SCIENCE, Issue 4 2006Shu-ichi Sugiyama Abstract Drought stress is one of the critical environmental factors in determining growth and survival of herbage grasses. In this study, by using a hydroponic culture system including different amounts of polyethylene glycol (PEG), responses of plant shoots to water stress in four different intensities (0 Mpa, ,0.6 Mpa, ,1.2 Mpa and ,1.8 Mpa) were examined in diploid and tetraploid cultivars of Italian ryegrass (Lolium multiflorum) and perennial ryegrass (L. perenne). Since freezing injury is caused by cell dehydration, freezing tolerance was also examined for six subzero temperatures (,11, ,12, ,14, ,16, ,18 and ,20°C) in both species. L. multiflorum had a larger shoot biomass at all stress intensities and a lower survival rate under severe water stress and freezing stress conditions than L. perenne. Thus, there was a trade-off (negative correlation) between potential growth under a stress-free condition and survival under a severe stress condition in diploid and tetraploid cultivars of both species. This trade-off was mediated by tissue water content. High water content led to a high growth rate through increasing specific leaf area, while low water content resulted in a high tissue osmotic potential that could confer high cell dehydration tolerance. [source] Hairy Root and Its Application in Plant Genetic EngineeringJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 2 2006Zhi-Bi Hu Abstract Agrobacterium rhizogenes Conn. causes hairy root disease in plants. Hairy root-infected A. rhizogenes is characterized by a high growth rate and genetic stability. Hairy root cultures have been proven to be an efficient means of producing secondary metabolites that are normally biosynthesized in roots of differentiated plants. Furthermore, a transgenic root system offers tremendous potential for introducing additional genes along with the Ri plasmid, especially with modified genes, into medicinal plant cells with A. rhizogenes vector systems. The cultures have turned out to be a valuable tool with which to study the biochemical properties and the gene expression profile of metabolic pathways. Moreover, the cultures can be used to elucidate the intermediates and key enzymes involved in the biosynthesis of secondary metabolites. The present article discusses various applications of hairy root cultures in plant genetic engineering and potential problems associated with them. (Managing editor: Wei Wang) [source] A UNIQUE LIFE CYCLE AND PERENNATION IN A COLORLESS CHRYSOPHYTE SPUMELLA SP.,JOURNAL OF PHYCOLOGY, Issue 1 2008Naoji Yubuki Life cycle and perennation of a colorless chrysophyte, Spumella sp., isolated from an ephemeral ditch were investigated. From a single resting cyst (statospore), only one nonmotile cell germinated. Shortly after germination, the cell generated flagella, started to swim, and formed a gelatinous sphere. The cell itself retained the ability to swim within the sphere. Cells fed on bacteria inhabiting the sphere and grew by longitudinal binary cell division very rapidly. The gelatinous sphere gradually enlarged as the number of cells increased. When it reached maximum size (,500 ,m in diameter), the gelatinous substance of the sphere weakened, and the sphere gradually broke into several pieces, forming cleavages between them. Cells swam away through the cleavages. Five to ,40 swimming cells soon gathered and formed a swarm. In the swarm, some cells cannibalized other sibling cells and enlarged, resulting in giant cells that were two to three times larger in diameter than ordinary cells. The giant cells soon started statospore formation. Statospore formation was independent of any changes of environmental factors, such as increase or decrease in temperature or changes in nutrient or light levels, which are known to induce resting-cyst formation in other groups of algae and protists. Statospore formation started when cells divided 15 to 16 times after germination. This is congruent with the idea that statospore formation in planktonic chrysophytes directly depends on cell density. An extraordinarily high growth rate and cannibalism involved in the initiation of statospore formation are interpreted as adaptations to achieve the perennation in ephemeral aquatic environments. [source] Form and environment of Gryphaea arcuataLETHAIA, Issue 2 2003LAETITIA NORI Gryphaea arcuata is one of the most studied fossils, but its detailed palaeoecology has been largely neglected. Specimens were collected within a short stratigraphic range (three ammonite zones) in the ,Calcaire à gryphées' of Xeuilley (Lorraine, France) dated Hettangian to Lower Sinemurian. As far as possible, they were sampled from each marly bed of the section. A biometric study and an isotopic analysis are compared in regard to organic matter measurements and palynological data, the results demonstrating a clear relationship between the shape of G. arcuata and environmental parameters. Factors responsible for the various shapes are temperature, oxygen levels on the sea floor and nutrient levels. Two main morphotypes can be related to two kinds of environment. In the first, controlled by a relatively hot and humid climate and tending towards eutrophication, the growth rate of Gryphaea was low, and the shells small, wide and thin. In the second environment, cooler than the first one and closer to the optimal living conditions of G. arcuata, the shell was large, thick and narrow, and exhibited a high growth rate. [source] Competitive exclusion as a mode of action of a novel Bacillus cereus aquaculture biological agentLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2010R. Lalloo Abstract Aims:, To determine the contribution of potential modes of action of a Bacillus cereus aquaculture biological control agent in inhibition of the fish pathogen, Aeromonas hydrophila. Methods and Results:, When B. cereus was tested in plate well inhibition studies, no production of antimicrobial compounds was detected. Bacillus cereus had a high growth rate (0·96 h,1), whereas Aer. hydrophila concentration decreased by c. 70% in co-culture experiments. In nutrient limitation studies, B. cereus had a significantly higher growth rate when cultured under glucose (P < 0·05) and iron (P < 0·01) limitation in comparison with Aer. hydrophila. Bacillus cereus glucose (0·30 g l,1 h,1) and iron (0·60 mg l,1 h,1) uptake rates were also significantly higher (P < 0·01) than the Aer. hydrophila glucose (0·14 g l,1 h,1) and iron (0·43 mg l,1 h,1) uptake rates. Iron uptake was facilitated by siderophore production shown in time profile studies where relative siderophore production was c. 60% through the late exponential and sporulation phases. Conclusions:, Competitive exclusion by higher growth rate, competition for organic carbon and iron, facilitated by siderophore production, could be identified as mechanisms of pathogen growth inhibition by B. cereus. Significance and Impact of the Study:, This study is the first elucidation of the mechanism of action of our novel B. cereus biological agent in growth attenuation of pathogenic Aer. hydrophila. This study enhances the application knowledge and attractiveness for adoption of B. cereus NRRL 100132 for exploitation in aquaculture. [source] Electrical and structural properties of p -type nanocrystalline silicon grown by LEPECVD for photovoltaic applicationsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010Gabriel Micard Abstract p-doped hydrogenated nanocrystalline silicon (p-nc-Si:H) is one of the most critical layers in thin film silicon solar cells. LEPECVD is a new technique for the growth of nc-Si at high growth rate without compromising the layer quality, using a dense but low energy plasma. Thin p-nc-Si:H layers are grown on glass and ZnO:Al coated glass and their structural and electrical properties are investigated as a function of the silane dilution (d) and of the doping ratio (DR). The influence of the substrate on the structural properties is investigated and discussed. The incubation layer is clearly observed on both substrate types and its thickness is estimated. LEPECVD distinguishes itself from other high growth rate methods by a very low impurity distribution coefficient to obtain a comparable conductivity and boron density. The conduction path is shown to be dependent on the density of boron in the layer while a significant decrease of conductivity at high DR is not observed in the studied range (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] High temperature growth of AlN film by LP-HVPEPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2007K. Tsujisawa Abstract AlN films were grown on AlN/sapphire templates at 1400,1500 °C using low-pressure hydride vapor phase epitaxy (LP-HVPE). Compared to the step-flow growth of AlN film at 1200 °C with growth rate of 2.1 ,m/h, AlN films with atomic steps were obtained at 1400,1500 °C even with high growth rate. For the AlN film grown at 1450 °C with growth rate of 14.3 ,m/h, the RMS value is 0.75 nm and the FWHM values of (0002) and (10-12) X-ray rocking curve (XRC) are 351 and 781 arcsec, respectively. Since the FWHM value of (10-12) XRC for the AlN/sapphire template is 1492 arcsec, the crystal quality of HVPE-grown AlN is greatly improved compared with the AlN/sapphire template, which is also confirmed by TEM observation. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A balanced amino acid diet improves Diplodus sargus larval quality and reduces nitrogen excretionAQUACULTURE NUTRITION, Issue 5 2009M. SAAVEDRA Abstract Fish larvae present high amino acid requirements due to their high growth rate. Maximizing this growth rate depends on providing a balanced amino acid diet which can fulfil larval amino acid nutritional needs. In this study, two experimental microencapsulated casein diets were tested: one presenting a balanced amino acid profile and another presenting an unbalanced amino acid profile. A control diet, live feed based, was also tested. Trials were performed with larvae from 1 to 25 days after hatching (DAH). Microencapsulated diets were introduced at 8 DAH in co-feeding with live feed and at 15 DAH larvae were fed the microencapsulated diets alone. Results showed a higher survival for the control group (8.6 ± 1.3% versus 4.2 ± 0.6% and 3.2 ± 1.8%) although dry weight and growth were similar in all treatments. The proportion of deformed larvae as well as the ammonia excretion was lower in the group fed a balanced diet than in the unbalanced or control groups (38.3% deformed larvae in control, 30% in larvae fed unbalanced diet and 20% on balanced diet group). Furthermore, larvae fed the microencapsulated diets presented higher docosahexaenoic acid and arachidonic acid levels. This study demonstrates that dietary amino acid profile may play an important role in larval quality. It also shows that balanced microencapsulated diets may improve some of the performance criteria, such as skeletal deformities, compared to live feeds. [source] Seasonal changes in selected muscle quality parameters in Atlantic salmon (Salmo salar L.) reared under natural and continuous lightAQUACULTURE NUTRITION, Issue 3 2003U. Nordgarden Abstract In order to investigate how seasonal variation in growth affects selected fillet quality parameters, immature Atlantic salmon (Salmo salar L.) were reared under simulated natural photoperiod (SNP) for 12 months or continuous light (LL) from January to June followed by SNP until December. Photoperiod treatments advanced the growth rate pattern of the LL group compared with the SNP group and influenced macronutrient metabolism, evaluated both as trends in protein and lipid retention and in fillet lipid and protein levels. Good growth was associated with low fillet lipid and protein level, in addition to reduced levels of fillet tocopherol and astaxanthin, indicating increased oxidative stress. Elevated levels of thiobarbituric reactive substances (TBARs) further supported this. Slaughtering during periods of high growth may therefore reduce postmortem quality, both because of increased susceptibility to fillet lipid peroxidation and reduced astaxanthin levels, which were lowered in vivo and might consequently be depleted further after slaughter. Specialized use of antioxidant-rich feed prior to slaughter is suggested if slaughtering is expected to occur during periods of high growth rate. [source] RAMPING UP AFRICAN GROWTH: LESSONS FROM FIVE DECADES OF GROWTH EXPERIENCEECONOMIC AFFAIRS, Issue 4 2006Benno J. Ndulu Since the 1960s economic growth rates have been far lower in sub-Saharan Africa than in other developing regions. This poor performance has resulted primarily from endemic rent-seeking and the over-regulation of markets. To achieve high growth rates, African countries must improve the investment climate by reforming institutions, enhancing infrastructure and protecting property rights. [source] The Influence of IMF Programs on the Re-election of Debtor GovernmentsECONOMICS & POLITICS, Issue 1 2004Axel Dreher The paper develops a model explaining why IMF programs are less likely to be concluded before national election dates. Since conclusion of an IMF arrangement may signal the incumbent's incompetence, rational voters use this signal when deciding upon his re-election. In order to demonstrate competence, politicians may therefore decide not to conclude IMF programs prior to elections. The model also shows that re-election probabilities of politicians who nevertheless conclude arrangements at election times depend on the state of the economy. Using panel data for 96 countries between 1976 and 1997, the model is tested empirically. The results show that conclusion of an IMF arrangement within six months prior to an election increases re-election probabilities when GDP growth is low, but reduces the chance to win an election with high growth rates. [source] Bacterial immobilization and remineralization of N at different growth rates and N concentrationsFEMS MICROBIOLOGY ECOLOGY, Issue 1 2005Per Bengtson Abstract An experiment was designed to resolve two largely unaddressed questions about the turnover of N in soils. One is the influence of microbial growth rate on mobilization and remineralization of cellular N. The other is to what extent heterotrophic immobilization of is controlled by the soil concentration of . Bacteria were extracted from a deciduous forest soil and inoculated into an aqueous medium. Various N pool dilution/enrichment experiments were carried out to: (1) calculate the gross N immobilization and remineralization rates; (2) investigate their dependence on concentrations; (3) establish the microbial preference for depending on the concentration ratio. Remineralization of microbial N occurred mainly at high growth rates and concentrations. There was a positive correlation between immobilization and remineralization rates, and intracellular recycling of N seemed to be an efficient way for bacteria to withstand low inorganic N concentrations. Thus, extensive remineralization of microbial N is likely to occur only when environmental conditions promote high growth rates. The results support previous observations of high immobilization rates, especially at low concentrations, but was also immobilized at high NH4 concentrations. The latter can be understood if part of the microbial community has a preference for . [source] Trophic interactions in the methanogenic microbial community of low-temperature terrestrial ecosystemsFEMS MICROBIOLOGY ECOLOGY, Issue 1 2005O.R. Kotsyurbenko Abstract The formation of methane in various ecosystems is due to the functioning of an anaerobic community, which combines trophically different groups of microorganisms. The methanogenic microbial community is a complex biological system, which responds to low temperatures by changes in its trophic structure resulting in redistributing matter flows. The enhanced activity of homoacetogenic bacteria at low temperature plays a significant role in this redistribution. Due to their relatively high growth rates and metabolic versatility, homoacetogens can successfully compete with fermenting bacteria and hydrogenotrophic methanogenic archaea for common substrates. The concentration of hydrogen is an important regulatory factor in the psychroactive methanogenic community. At low temperature methanogenic archaea possessing a higher affinity for hydrogen than homoacetogens provide for interspecies H2 transport in syntrophic reactions of fatty acid decomposition. The formation of a balanced community at low temperature is a longtime process. Cold terrestrial ecosystems are dominated by psychroactive (psychrotolerant) microorganisms, which can grow over a wide range of ambient temperatures. [source] Broadbill swordfish: status of established fisheries and lessons for developing fisheriesFISH AND FISHERIES, Issue 4 2000P. Ward Guidelines for the assessment and management of developing swordfish fisheries are derived through an examination of five swordfish fisheries. As they develop, swordfish fisheries may be inclined to local depletion around underwater features, such as seamounts and banks. Few nations have applied the precautionary approach in managing their developing swordfish fisheries. Without controls, swordfish fisheries expand geographically and fishing effort increases, often overshooting optimum levels. However, it is difficult to distinguish clear evidence of fishery collapse; modern longliners harvest widely distributed tuna and swordfish and they are able to relocate to distant areas or switch between target species in response to fluctuations in species abundance and price. Furthermore, the wide distribution of swordfish combined with year-round spawning and high growth rates amongst juveniles probably contribute to the apparent resilience of swordfish stocks to intensive harvesting. Over half the world's swordfish catch is taken as an incidental catch of longliners fishing for tuna. In several areas, such as the North Atlantic, catch quotas have sometimes caused tuna longline fishers to discard swordfish. Minimum size limits have also resulted in discarding of swordfish in tuna fisheries and in dedicated swordfish fisheries. In addition to weakening the effectiveness of those management measures, bycatch and discarding add to the complexities of managing swordfish fisheries and to uncertainties in assessing the stocks. Longliners that target swordfish often fish at high latitudes where interactions with marine wildlife, such as seabird, are generally more frequent than at low latitudes. Concern over incidental catches of marine wildlife and other species is becoming a driving force in the management of several swordfish fisheries. Fishery management organisations will need to implement management measures to protect non-target species and gather reliable data and information on the situation by placing observers on boats fishing for swordfish. [source] Variation in Serripes groenlandicus (Bivalvia) growth in a Norwegian high-Arctic fjord: evidence for local- and large-scale climatic forcingGLOBAL CHANGE BIOLOGY, Issue 9 2006WILLIAM G. AMBROSE Jr. Abstract We examined the growth rate of the circumpolar Greenland Cockle (Serripes groenlandicus) over a period of 20 years (1983,2002) from Rijpfjord, a high-Arctic fjord in northeast Svalbard (80°10,N, 22°15,E). This period encompassed different phases of large-scale climatic oscillations with accompanying variations in local physical variables (temperature, atmospheric pressure, precipitation, sea ice cover), allowing us to analyze the linkage between growth rate, climatic oscillations, and their local physical and biological manifestations. Standard growth index (SGI), an ontogenetically adjusted measure of annual growth, ranged from a low of 0.27 in 2002 up to 2.46 in 1996. Interannual variation in growth corresponded to the Arctic climate regime index (ACRI), with high growth rates during the positive ACRI phase characterized by cyclonic ocean circulation and a warmer and wetter climate. Growth rates were influenced by local manifestations of the ACRI: positively correlated with precipitation and to a lesser extent negatively correlated with atmospheric pressure. A multiple regression model explains 65% of the variability in growth rate by the ACRI and precipitation at the nearest meteorological station. There were, however, complexities in the relationship between growth and physical variables, including an apparent 1 year lag between physical forcing changes and biological response. Also, when the last 4 years of poor growth are excluded, there is a very strong negative correlation with ice cover on a pan-arctic scale. Our results suggest that bivalves, as sentinels of climate change on multi-decadal scales, are sensitive to environmental variations associated with large-scale changes in climate, but that the effects will be determined by changes in environmental parameters regulating marine production and food availability on a local scale. [source] Vegetative growth and development of irrigated forage turnip (Brassica rapa var. rapa)GRASS & FORAGE SCIENCE, Issue 4 2008J. E. Neilsen Abstract Field and greenhouse experiments were conducted to identify visual markers and predictors of changes in the vegetative growth rate of forage turnip (Brassica rapa var. rapa) as a potential tool to improve the timing of inputs of N and irrigation to periods of maximum demand. The onset of root expansion, which was associated with a colour change and the death of cotyledons, was identified as a critical marker for the beginning of the rapid growth of the crop and the accumulation of starch in the storage root but indicators of subsequent changes in vegetative growth rate were not identifiable. The results suggested that management inputs can be more readily targeted to the beginning of the exponential growth phase but targeting of later vegetative growth stages will remain arbitrary. The vegetative growth and development of the crop was also studied to elucidate the process of leaf emergence and senescence (turnover) as they affected both leaf and root yield. The sequential senescence of leaves, which began immediately after cotyledon death, and translocation of carbohydrate to the storage root, coupled with high leaf area index (LAI), probably account for the high growth rates of 220 kg ha,1 day,1 maintained for periods of 10 weeks after the onset of root expansion. High yields can be expected if high LAI is maintained by ensuring that leaf emergence rates are not limited by nutrient or water deficiencies and leaves are protected from insect pests. Forage turnip is particularly robust because new leaf continues to emerge as older and damaged leaves senesce and carbohydrate is stored as starch in the storage root. [source] Property Rights and Public Interests: A Wyoming Agricultural Lands StudyGROWTH AND CHANGE, Issue 1 2002Katherine Inman Rocky Mountain states have experienced unprecedented growth as agricultural land is converted to residences. Preservation efforts meet with protest from private landholders claiming public efforts undermine private property rights. This paper explores the degree to which respondents think management of agricultural lands is a public versus a private matter. Data are from a Sublette County, Wyoming, mail survey. Results are relevant to many western counties having public lands and high growth rates. They suggest that landowners, wage earners, college graduates, and those who value the county's rural community lifestyle support public management strategies. Well-established residents and those with economic reasons for living in the county support private management strategies. [source] Growth of Thick MgB2 Films by Impinging-Jet Hybrid Physical-Chemical Vapor Deposition,ADVANCED MATERIALS, Issue 2 2008R. Lamborn Thick MgB2 films are grown using a novel impinging-jet hybrid physical-chemical vapor deposition process. An increased amount of the boron source gas generates high growth rates. Superconducting properties of the thick films are comparable to previous results from other processes, which indicate that this is a promising new process for MgB2 deposition for coated conductor applications, such as wires and tapes for MRI magnets. [source] To sample or eradicate?JOURNAL OF APPLIED ECOLOGY, Issue 4 2008A cost minimization model for monitoring, managing an invasive species Summary 1Considerable effort is expended by national and local governments to exclude alien species via detection and eradication of invading populations, but these efforts are not necessarily designed in the most economically or biologically efficient manner. 2Using the invasion of the European strain of the gypsy moth Lymantria dispar into the USA as a case study, we develop an analytical model to determine the optimal trap density for detecting isolated infestations. Most models focus on monitoring or eradication costs only; our model considers the costs of both detection and eradication when determining the best monitoring strategy. 3The model assumes that all isolated populations must be located and eradicated by the conclusion of a programme. For programmes lasting longer than 1 year, it is more worthwhile to proactively monitor and manage rather than to wait until the programme is over. 4For a management programme of a given length, optimal trap density is most influenced by the growth rate of the infestation. Optimal trap densities are lowest for infestations with very low growth rates (because they remain small and therefore are less expensive to eradicate) or very high growth rates (because they are easier to detect), and highest for infestations with moderate growth rates (because they are neither inexpensive to eradicate nor easy to detect). 5Our model is useful in setting a baseline level of monitoring for isolated incidents of gypsy moth invasion. Analysis of data in two US states show that actual trap densities are far higher than the optimal densities from the model. The difference suggests risk aversion may play a role in real systems. 6Synthesis and applications. Our model suggests that we can improve the efficiency of detection and eradication programmes for isolated infestations by optimizing detection effort relative to infestation growth rates and management programme duration. It also clearly demonstrates the importance of balancing the costs and benefits of both detection and eradication when developing invasive species monitoring programmes. [source] Dimorphic growth patterns and sex-specific reaction norms in the butterfly Lycaena hippothoe sumadiensisJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 2 2001K. Fischer Directly developing larvae of the butterfly Lycaena hippothoe sumadiensis exhibited two growth strategies with one cohort passing four larval instars at high growth rates, and the other five instars at lower growth rates. The 4-instar-cohort displayed decreased development times, in combination with slightly reduced pupal and adult weights. In addition to adjustment of growth rate, omitting a larval instar may comprise a further mechanism to decrease development time when needed. Using the 4-instar-cohort, sex-related differences in reaction norms were investigated over a temperature gradient. At high temperatures, protandrous males showed early emergence at a reduced size, whereas weight of females remained similar throughout. These differences suggest that large size is more important for female than for male fitness. The pattern is similar to that previously reported for alpine L. tityrus, indicating that sex-specific reaction norms might be widespread in species living under severe time constraints. [source] Hypoxia tolerance of the mummichog: the role of access to the water surfaceJOURNAL OF FISH BIOLOGY, Issue 3 2003K. L. Stierhoff Low dissolved oxygen (DO) had a significant effect on specific growth rate (GS), length increment (IL) and haematocrit (Hct) of the mummichog Fundulus heteroclitus. Regardless of access to the water surface, F. heteroclitus maintained high growth rates (GS and IL) at DO concentrations as low as 3 mg O2 l,1. With access to the water surface, both GS and IL of F. heteroclitus decreased by c. 60% at 1·0 mg O2 l,1 compared to all higher DO treatments. When denied access to the water surface, a further decrease in GS (c. 90%) and IL (c. 75%) was observed at 1 mg O2 l,1. There was no effect of diel-cycling DO (1,11 mg O2 l,1) with or without surface access on GS, IL or Hct of F. heteroclitus. Similar trends between GS and faecal production across DO treatments suggest that decreased feeding contributed significantly to the observed decrease in growth rate. Haematocrit was significantly elevated at 1 mg O2 l,1 for fish with and without access to the water surface. Increased Hct, however, was not sufficient to maintain high GS or IL at severely low DO. When permitted to respire in the surface layer, however, F. heteroclitus was capable of maintaining moderate growth rates at DO concentrations of 1 mg O2 l,1 (c. 15% saturation). Although aquatic surface respiration (ASR) was not quantified in this study, F. heteroclitus routinely swam in contact with the water surface and performed ASR at DO concentrations ,3 mg O2 l,1. No hypoxia-related mortality was observed in any DO or surface access treatment for as long as 9 days. This study demonstrates that surface access, and thus potential for ASR, plays an important role in providing F. heteroclitus substantial independence of growth rate over a wide range of low DO conditions commonly encountered in shallow estuarine environments. [source] Born Global Firms and Informal Investors: Examining Investor CharacteristicsJOURNAL OF SMALL BUSINESS MANAGEMENT, Issue 4 2008Øystein Moen A "Born Global" is a new venture with a global niche market focus from day one. Many of these firms experience high growth rates, but also, a considerable need for funding. This study contrasts informal investors involved in born global firms ("Born Global Investors") with other informal investors. The underlying thesis is that the behavior of these investors reflects their investment philosophy, at least on a differential basis. The results suggest that born global investors differ from other informal investors in terms of deal origin, investment size, and exit preferences. Their experience as managers of large firms seems to be a particularly important factor, increasing investment capacity (income and fortune), while personal and professional networks influence the access to information about investment opportunities. The importance of these results for the development of born global firms is discussed. [source] Pilot Production of Hatchery-Reared Summer Flounder Paralichthys dentatus in a Marine Recirculating Aquaculture System: The Effects of Ration Level on Growth, Feed Conversion, and SurvivalJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2005Patrick M. Carroll Pilot-scale trials were conducted to evaluate growout performance of hatchery-reared summer flounder fingerlings in a state-of-the-art recirculating aquaculture system (RAS). The outdoor RAS consisted of four 4.57-m dia × 0.69-m deep (vol. =11.3 m3) covered, insulated tanks and associated water treatment components. Fingerlings (85.1 g mean initial weight) supplied by a commercial hatchery were stocked into two tanks at a density of 1,014 fish/tank (7.63 kg/m3). Fish were fed an extruded dry floating diet consisting of 50% protein and 12% lipid. The temperature was maintained between 20 C and 23 C and the salinity was 34 ppt. Under these conditions, growth, growth variation (CVwt), feed utilization, and survival of fish fed to 100% and 82% of a satiation rate were compared. Due to clear changes in growth patterns during the study, data was analyzed in three phases. During phase 1 (d 1,d 196), fish showed rapid growth, reaching a mean weight of 288 g ± 105 and 316 g ± 102, with a CVwt of 0.36 and 0.32 and FCR's of 1.38 and 1.36 in the subsatiation and satiation groups, respectively. During phase 2 (d 196,d 454), fish displayed slower growth reaching mean weights of 392 g ± 144 and 436 g ± 121, with a CVwt of 0.37 and 0.28, and increasing FCR's of 3.45 and 3.12 in the subsatiation and satiation groups, respectively. During phase 3 (d 454,d 614), fish showed little growth reaching mean weights of 399 g ± 153 and 440 g ± 129, with a CVwt of 0.38 and 0.29 in the subsatiation and satiation groups, respectively. Over the entire growout period (d 1,d 614), feed conversion ratios were 2.39 and 2.37 and survival was 75% and 81 % in the subsatiation and satiation treatments, respectively. The maximum biomass density reached during the study was 32.3 kg/m3. The satiation feed rate was superior to the 82% satiation rate, since it maximized growth rates, with no effect on FCR. The higher CVwt in the subsatiation group suggests increased competition for a restricted ration led to a slower growth with more growth variation. The decrease in growth in phases 2 and 3 was probably related to a high percentage of slower growing male fish in the population and the onset of sexual maturity. This study demonstrated that under commercial scale conditions, summer flounder can be successfully grown to a marketable size in a recirculating aquaculture system. Based on these results, it is recommended that a farmer feed at a satiation rate to minimize growout time. More research is needed to maintain high growth rates through marketable sizes through all-female production and/or inhibition of sexual maturity. [source] An analysis of the factory model for chromosome replication and segregation in bacteriaMOLECULAR MICROBIOLOGY, Issue 4 2001James Sawitzke Recent advances in microscopy have given us important clues as to the nature of chromosome segregation in bacteria. Most current observations favour the view that the process is co-replicational: DNA replication forks are anchored at the cell centre, and the newly replicated DNA is moved towards the cell poles. This scheme can account for orderly segregation even at high growth rates where multiple replication cycles overlap. We argue that there are five distinct activities directly involved in co-replicational segregation dynamics. These we refer to as Push, Direct, Condense, Hold and Clear. We attempt to assign one of these roles to each protein implicated in chromosome segregation. The proposed process is very different from mitosis in eukaryotic cells and perhaps more closely resembles the formation of separate sister chromatids during DNA replication. [source] Differences between chloro-carbon and hydro-carbon precursors in low-temperature epitaxial growth of 4H-SiCPHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 7 2010Siva Kotamraju Abstract The advantages of using the chlorinated carbon precursor chloromethane instead of the hydrocarbon precursor propane in low-temperature (1300 °C) epitaxial growth of 4H-SiC were investigated. Chloromethane was found to provide a much wider process window for variation of the C/Si ratio between the lower boundary corresponding to the formation of condensed silicon face and the upper boundary corresponding to polytype inclusions and polycrystalline degradation, which is critical for achieving high growth rates without epilayer quality degradation. Use of a high Cl/Si ratio provided by HCl addition in the propane-based epitaxial growth did not eliminate the critical differences between chloro-carbon and hydro-carbon precursors. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Nanosized Diamond Deposition via Plasma MediumPLASMA PROCESSES AND POLYMERS, Issue S1 2007Babak Shokri Abstract An arc jet plasma technique is used to produce nanosized diamond particle deposition and for the deposition of diamond-like carbon at high growth rates. In this case, atomic hydrogen produced in the arc plasma participates in the methane decomposition. In addition, a thermodynamic modeling will be presented for the nucleation of stable diamond as nanoparticles and thin films and the computation was made in the range of the applied plasma reactor. [source] | ||||||||||||||||||||||