Home About us Contact
|
Home About us Contact | ||
|
|
||
Faster Growth Rates (faster + growth_rate)
Selected AbstractsStructural biomass partitioning in regrowth and undisturbed mesquite (Prosopis glandulosa): implications for bioenergy usesGCB BIOENERGY, Issue 1 2010R. JAMES ANSLEY Abstract Honey mesquite (Prosopis glandulosa Torr.) which grows on grasslands and rangelands in southwestern USA may have potential as a bioenergy feedstock because of existing standing biomass and regrowth potential. However, regrowth mesquite physiognomy is highly different from undisturbed mesquite physiognomy and little is known regarding growth rates and structural biomass allocation in regrowth mesquite. We compared canopy architecture, aboveground biomass and relative allocation of biomass components in regrowth (RG) trees of different known ages with undisturbed (UD) trees of similar canopy height to each RG age class. RG trees in most age classes (2,12 years old) had greater canopy area, leaf area, basal stem number, twig (<0.5 cm diameter) mass and small stem (0.5,3 cm diameter) mass than UD trees of the same height. Large stem (>3 cm diameter) mass was similar between RG and UD trees in all height classes. Ages of UD trees were determined after harvest and further comparisons were made between age, canopy structure and biomass in RG and UD trees. Relationships between age and total mass, age and height, and age and canopy area indicated a faster growth rate in RG than in UD trees. Large stem mass as a percentage of total tree mass accumulated more rapidly with age in RG than UD trees. Leaf area index and leaf : twig mass ratio were maintained near 1 in all RG and UD trees. Regrowth potential may be one of the most important features of mesquite in consideration as a bioenergy feedstock. [source] EFFECT OF STORAGE TEMPERATURE ON THE GROWTH OF LISTERIA MONOCYTOGENES ON QUESO BLANCO SLICES,JOURNAL OF FOOD SAFETY, Issue 3 2006GAYLEN A. UHLICH ABSTRACT A five-strain cocktail of Listeria monocytogenes (104 cfu/mL) was inoculated onto individual vacuum-packaged slices (ca. 50 g each) of a commercial, Hispanic-style cheese, that being Queso Blanco. Growth was determined at appropriate intervals during storage at 5, 10, 15, 20 and 25C. In general, as the incubation temperature increased, a shorter lag phase duration (LPD) and a faster growth rate (GR) were observed. The LPD values at 5, 10, 15, 20 and 25C were 65.3, 19.9, 2.1, 8.4 and 11.4 h, respectively. The GR values were 0.011, 0.036, 0.061, 0.090 and 0.099 log cfu/h at 5, 10, 15, 20 and 25C, respectively. There were no statistical differences in LPD at 10, 15, 20 and 25C. However, the LPD during growth at 5C was statistically (P , 0.05) longer than at all other temperatures. The GR values at 20 and 25C were not significantly different from each other, whereas the GR values at 5, 10 and 15C were significantly different from each other as well as from the GR at 20 and 25C (P , 0.05). The maximum population density (MPD) showed relatively little variation over the range of storage temperatures tested, with an average of 8.38 log cfu/g (SD = 0.33). The results of this study indicate that not even the lowest trial temperature of 5C prevented growth over time of the inoculated L. monocytogenes on this sliced product, and that proper storage and handling procedures are required to prevent the bacterium from contaminating the product and/or to control its growth. [source] Development of garnet porphyroblasts by multiple nucleation, coalescence and boundary misorientation-driven rotationsJOURNAL OF METAMORPHIC GEOLOGY, Issue 3 2001R. Spiess Abstract Two types of garnet porphyroblast occur in the Schneeberg Complex of the Italian Alps. Type 1 porphyroblasts form ellipsoidal pods with a centre consisting of unstrained quartz, decussate mica and small garnet grains, and a margin containing large garnet grains. Orientation contrast imaging using the scanning electron microscope shows that the larger marginal garnet grains comprise a number of orientation subdomains. Individual garnet grains without subdomains are small (< 50 µm), faceted and idioblastic, and have simple zoning profiles with Ca-rich cores and Ca-poor rims. Subdomains of larger garnet grains are similar in size to the individual, small garnet grains. Type 2 porphyroblasts comprise only ellipsoidal garnet, with small subdomains in the centre and larger subdomains at the margin. Each subdomain has its own Ca high, Ca dropping towards subdomain boundaries. Garnet grains, with or without subdomains, all have the same Ca-poor composition at rims in contact with other minerals. The compositional zonation patterns are best explained by simultaneous, multiple nucleation, followed by growth and amalgamation of individual garnet grains. The range of individual garnet and garnet subdomain sizes can be explained by a faster growth rate at the porphyroblast margin than in the centre. The difference between Type 1 and Type 2 porphyroblasts is probably related to the growth rate differential across the porphyroblast. Electron backscatter diffraction shows that small, individual garnet grains are randomly oriented. Large marginal garnet grains and subdomain-bearing garnet grains have a strong preferred orientation, clustering around a single garnet orientation. Misorientations across subdomain boundaries are small and misorientation axes are randomly oriented with respect to crystallographic orientations. The only explanation that fits the observational data is that individual garnet grains rotated towards coincident orientations once they came into contact with each other. This process was driven by the reduction of subdomain boundary energy associated with misorientation loss. Rotation of garnet grains was accommodated by diffusion in the subdomain boundary and diffusional creep and rigid body rotation of other minerals (quartz and mica) around the garnet. An analytical model, in which the kinetics of garnet rotation are controlled by the rheology of surrounding quartz, suggests that, at the conditions of metamorphism, the rotation required to give a strong preferred orientation can occur on a similar time-scale to that of porphyroblast growth. [source] Aluminum Silicate Films Obtained by Low-Pressure Metal-Organic Chemical Vapor DepositionJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2003Dong-Hau Kuo Amorphous alumina-silica films with film thickness of 0.41,2.69 ,m were prepared on glass and silicon substrates by metal-organic chemical vapor deposition using a mixture of aluminum tri-sec-butoxide (ATSB), hexamethyldisilazane (HMDSN), and argon. By controlling the inputs of ATSB and HMDSN, alumina-silica thin films could contain varied compositions and adjustable properties. Basically, the codeposition of alumina and silica to form alumina-silica using ATSB and HMDSN had a faster growth rate than their individual components. The internal stress could be adjusted by deposition temperature and reactant inputs. Adhesion could be improved by having a silicon-rich thin film, whereas an aluminum-rich film could have slightly higher hardness. Optical properties, e.g., refractive index and optical transmittance, were also measured. [source] Growth and movement patterns of early juvenile European anchovy (Engraulis encrasicolus L.) in the Bay of Biscay based on otolith microstructure and chemistryFISHERIES OCEANOGRAPHY, Issue 3 2010NAROA ALDANONDO Abstract Various hypotheses have been put forward to explain the mechanisms in the Bay of Biscay that result in a good recruitment of European anchovy. Anchovy larvae from the spawning area in the Gironde River plume are advected towards off-shelf waters, where juveniles are commonly observed. Otolith microstructural and chemical analysis were combined to assess the importance of this off-shelf transport and to determine the relative contribution of these areas for anchovy survival. Chemical analysis of otoliths showed that anchovy juveniles in the Bay of Biscay can be divided into two groups: a group that drifts towards off-shelf waters early in their life and returns later, and a group that remains in the low salinity waters of the coastal area. The first group presents significantly faster growth rates (0.88 mm day,1) than those remaining in the coastal waters (0.32 mm day,1). This may be due to off-shelf waters being warmer in spring/summer, and to the fact that the lower food concentration is compensated for by higher prey visibility. Furthermore, the group of juveniles that drifted off the spawning area and had faster growth rates represents 99% of the juvenile population. These findings support the hypothesis that anchovy in the Bay of Biscay may use off-shelf waters as a spatio-temporal loophole, suggesting that transport off the shelf may be favourable for recruitment. [source] Calcite Growth in Hydrogels: Assessing the Mechanism of Polymer-Network Incorporation into Single CrystalsADVANCED MATERIALS, Issue 4 2009Hanying Li Calcite crystals grown in agarose hydrogels incorporate the gel network while retaining their single-crystal nature. The amount of gel network that is incorporated is determined by two competing factors: crystallization pressure promotes the exclusion of the gel network, while faster growth rates favor its incorporation. [source] Sex-biased juvenile survival in a bird with extreme size dimorphism, the great bustard Otis tardaJOURNAL OF AVIAN BIOLOGY, Issue 3 2007Carlos A. Martín We explored sex-biased mortality patterns in a species showing the most extreme sexual dimorphism among birds, the great bustard Otis tarda. Between 1991 and 2005 we studied juvenile and immature survival in a sample of 361 great bustards radio-tagged at two different populations in Spain, Villafáfila and Madrid. Mortality decreased with age, from high rates during the first year (0.70), to 0.10 in the second year. Using the known-fate model in program MARK we found that monthly survival increased throughout the first year. Offspring showing higher body mass at marking, i.e. those hatched earlier in the season and those with better body condition, survived in higher proportion. This was probably related to the earlier breeding dates of more experienced mothers, as well as to the observed decrease in food availability as the season progresses. Monthly survival estimates were higher in females than in males, which suggests that juvenile males are more vulnerable to reduced food availability and other factors due to their much faster growth rates. The proportion of non-natural deaths increased with age, and was higher in the Madrid population, where illegal hunting and collision with powerlines showed a high incidence. The male-biased mortality found in young birds in this study explains the female-biased population sex ratios observed in great bustard populations. The different degrees of incidence of human-induced causes of mortality found between both populations studied suggest that such differences may contribute to the variation observed in the adult sex ratio among populations. [source] Natural disturbance and life history: consequences of winterkill on fathead minnow in boreal lakesJOURNAL OF FISH BIOLOGY, Issue 3 2006A. J. Danylchuk Age, growth and reproductive characteristics of fathead minnow Pimephales promelas populations inhabiting four lakes that varied in the extent and frequency of winterkill were studied in the boreal region of western Canada. The lifespan of fathead minnows inhabiting lakes prone to winterkill was 1,2 years shorter than those in less disturbed lakes. In populations prone to winterkill, fish displayed faster growth rates and grew to a larger size-at-age, particularly during the first year of life. Although lower population densities in winterkill lakes probably contributed to this increased growth, adults in these populations tended to spawn earlier in the season than the smaller adults in more stable populations. Fathead minnows in lakes prone to winterkill also matured at an earlier age and allocated a greater proportion of their body mass to gonads than conspecifics in the more benign, stable lakes. These trends are consistent with predictions for organisms in variable, unpredictable environments and, because fathead minnows are tolerant to a wide range of environmental conditions, suggest that variation in life-history traits among populations is probably a product of both selection and phenotypic plasticity. [source] Economic Feasibility of Aquaculture of Spiny Lobsters Jasus edwardsii in Temperate WatersJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2000Andrew Jeffs Around the world there is strong interest in the aquaculture of spiny lobsters (family Palinuridae). However, there is little published information about the economic feasibility of spiny lobster aquaculture. For more than 20 yr there has been experimental grow out of the spiny lobster Jasus edwardsii in New Zealand in land-based systems using seed animals (puerulus) taken from the wild. These studies provide sufficient information on growth, mortality, food conversion, handling and capital costs to enable an assessment of the economic feasibility of the commercial culture of spiny lobsters in temperate waters. This assessment suggests that profitable spiny lobster aquaculture will rely on greatly reducing the infrastructure and operating costs of land-based farming operations, as well as lowering feed and labor costs. Financial simulations suggest that increasing productivity through faster growth rates and lowered culture mortalities will only have a minor effect on profitability unless infrastructure and operating costs can be reduced significantly. Seacage culture or sea ranching of spiny lobsters may offer a means of avoiding high infrastructure costs associated with land-based farming operations. The development of a cost-effective artificial feed would also appear to be a priority for improving the economic outlook for culturing spiny lobsters. The results of this study are relevant to the economics of spiny lobster culture developments in other temperate regions of the world. [source] Soft-tissue imprints in fossil and Recent cephalopod septa and septum formationLETHAIA, Issue 4 2008CHRISTIAN KLUG Several soft-tissue imprints and attachment sites have been discovered on the inside of the shell wall and on the apertural side of the septum of various fossil and Recent ectocochleate cephalopods. In addition to the scars of the cephalic retractors, steinkerns of the body chambers of bactritoids and some ammonoids from the Moroccan and the German Emsian (Early Devonian) display various kinds of striations; some of these striations are restricted to the mural part of the septum, some start at the suture and terminate at the anterior limit of the annular elevation. Several of these features were also discovered in specimens of Mesozoic and Recent nautilids. These structures are here interpreted as imprints of muscle fibre bundles of the posterior and especially the septal mantle, blood vessels as well as the septal furrow. Most of these structures were not found in ammonoids younger than Middle Devonian. We suggest that newly formed, not yet mineralized (or only slightly), septa were more tightly stayed between the more numerous lobes and saddles in more strongly folded septa of more derived ammonoids and that the higher tension in these septa did not permit soft-parts to leave imprints on the organic preseptum. It is conceivable that this permitted more derived ammonoids to replace the chamber liquid faster by gas and consequently, new chambers could be used earlier than in other ectocochleate cephalopods, perhaps this process began even prior to mineralization. This would have allowed faster growth rates in derived ammonoids. [source] Electron transport properties of low sheet-resistance two-dimensional electron gases in ultrathin AlN/GaN heterojunctions grown by MBEPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008Yu Cao Abstract A study of the transport properties of polarizationinduced 2DEGs at MBE-grown single AlN/GaN heterostructures with different growth rates is reported. It is observed that faster growth rates lead to high mobilities, approaching , 1600 cm2/Vs at 300 K and , 6000 cm2/Vs at low temperatures for ultrathin (2.3 nm AlN/GaN) heterojunctions. By using a theoretical model in conjunction with experimentally measured transport properties, it is concluded that the 300 K sheet resistances of very high density 2DEGs at AlN/GaN heterojunctions are currently limited (, 170 , /,) by interface roughness scattering, and can be further reduced by improving the growth conditions. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Investigating atmospheric predictability on Mars using breeding vectors in a general-circulation modelTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 603 2004C. E. Newman Abstract A breeding vectors approach is used to investigate the hypothesis that the Martian atmosphere is predictable at certain times of year, by identifying the fastest-growing modes of instability at different times in a Mars general-circulation model. Results indicate that the period from northern mid-spring until mid-autumn is remarkably predictable, with negative global growth rates for a range of conditions, in contrast to the situation on the earth. From northern late autumn to early spring growing modes do occur, peaking in northern high latitudes and near winter solstice. Reducing the size of the initial perturbations increases global growth rates in most cases, supporting the idea that instabilities which saturate nonlinearly at lower amplitudes have generally faster growth rates. In late autumn/early winter the fastest-growing modes (,bred vectors') are around the north pole, increase with dust loading, and probably grow via barotropic as well as baroclinic energy conversion. In northern late winter/early spring the bred vectors are around the north pole and are strongly baroclinic in nature. As dust loading (and with it the global circulation strength) is increased their growth rates first decrease, as the baroclinic mode is suppressed, then increase again as the fastest-growing instabilities switch to being those which dominated earlier in the year. If dust levels are very low during late northern autumn (late southern spring) then baroclinic modes are also found around the spring pole in the south, though for a slight increase in dust loading the dominant modes shift back to northern high latitudes. The bred vectors are also used as perturbations to the initial conditions for ensemble simulations. One possible application within the Mars model is as a means of identifying regions and times when dust-lifting activity (related to surface wind stress) might show significant interannual variability for a given model configuration, without the need to perform long, computationally expensive multi-year model runs with each new set-up. This is tested for a time of year when previous multi-year experiments showed significant variability in dust storm onset in the region north of Chryse. Despite the model having no feedbacks between dust lifting and atmospheric state (unlike the original multi-year run), the ensemble members still show maximum divergence in this region in terms of near-surface wind stress, suggesting both that this application deserves further testing, and that the intrinsic atmospheric variability alone may be important in producing interannual variability in this storm type. Copyright © 2004 Royal Meteorological Society [source] Nursery rearing of the Asian catfish, Clarias macrocephalus (Günther), at different stocking densities in cages suspended in tanks and pondsAQUACULTURE RESEARCH, Issue 13 2002Ruby F Bombeo Abstract Growth and survival of hatchery-bred Asian catfish, Clarias macrocephalus (Günther), fry reared at different stocking densities in net cages suspended in tanks and ponds were measured. The stocking densities used were 285, 571 and 1143 fry m,3 in tanks and 114, 228 and 457 fry m,3 in ponds. Fish were fed a formulated diet throughout the 28-day rearing period. Generally, fish reared in cages in ponds grew faster, with a specific growth rate (SGR) range of 10.3,14.6% day,1, than those in cages suspended in tanks (SGR range 9,11.3% day,1). This could be attributed to the presence of natural zooplankton (copepods and cladocerans) in the pond throughout the culture period, which served as additional food sources for catfish juveniles. In both scenarios, the fish reared at lower densities had significantly higher SGR than fish reared at higher densities. In the pond, the SGR of fish held at 228 and 457 m,3 were similar to each other but were significantly lower than those of fish held at 114 m,3. The zooplankton in ponds consisted mostly of copepods and cladocerans, in contrast to tanks, in which rotifers were more predominant. Per cent survival ranged from 85% to 89% in tanks and from 78% to 87% in ponds and did not differ significantly among stocking densities and between rearing systems. In conclusion, catfish nursery in cages suspended in tanks and ponds is density dependent. Catfish fry reared at 285 m,3 in tanks and at 114 m,3 in ponds had significantly faster growth rates than fish reared at higher densities. However, the desired fingerling size of 3,4 cm total length for stocking in grow-out culture can still be attained at stocking densities of 457 m,3 in nursery pond and 571 m,3 in tanks. [source] | ||||||||||||||||