Fast Growers Research Articles

English

A study was conducted to evaluate the production performance of koekoek chickens at Adami Tulu Research Center. Feed consumption, age at point of laying, annual egg production, mortality, and egg quality parameters were used as evaluation parameters. Mean feed consumption of starter, grower and layer of koekoek chickens at Adami Tulu Research Center was 56.4±4.6, 84.3±6.3 and 124±8.6 g/day, respectively. Koekoek chickens attain sexual maturity at 5 months and produce 213± 12.4 eggs per year. Their hatchability was 60% and mortality rate was 4% at Adami Tulu Research center.  Their egg weight in gram (g) was 51.17±3.2.  The egg yolk color, yolk weight in gram (g), albumin weight in gram (g) were 5.08±0.91, 14.96±1.6 and 31.2±2.7, respectively. The current study revealed that koekoek chickens adapt well to semi-arid agro-ecology of Ethiopia. Koekoek chickens are fast growers and good layers. So day-old chicken producers and distributors in semi-arid area can consider them as candidate breeds in their production. These dual purpose breeds need good managements like quality feed provision, good sanitation and vaccine administration. Therefore livestock extensions and farmers who have interest in introducing these breeds into their farm should have to provide necessary management practices to fully utilize their production potential. Key words: Poultry breed, farming system, egg performance, mortality rate. &nbsp

Mining and Predicting Temporal Patterns in the Quality Evolution of Wikipedia Articles

In online open production communities like Wikipedia, quality is often an important criterion to assess the success of peer collaboration activities. Over the years we have accumulated a nice body of knowledge on what factors may affect work quality in online open collaboration, whether it was open source projects or Wikipedia articles. Most studies, however, were cross sectional or correlational in nature and fail to capture the dynamic process through which quality of an open collaboration project evolves over time along different trajectories. Online open collaboration systems like Wikipedia are complex adaptive systems within which large numbers of editors, artifacts, and factors interact, influence, and co-evolve with one another. These systems often exhibit history dependence in the sense that what happens in the early days of an article affect its subsequent development. In this paper, we aim to uncover common patterns in the dynamic evolution of article quality by applying a powerful time-series clustering tool to cluster quality changes of 1,073 road infrastructure articles from Wikipedia. Our clustering reveals three distinctive trajectories of article quality growth toward good article (GA) status: fast riser, incremental grower, and late bloomer. Moreover, multinomial analysis shows that: 1) fast-risers and incremental-growers both had greater topical importance, but the former were more likely to attract an initial crowd with greater domain experiences and 2) late-bloomers were similar to incremental-growers in early activities and characteristics of initial crowd, but had significantly lower topical importance.

Insights into the carbonic anhydrases and autotrophic carbon dioxide fixation pathways of high CO2 tolerant Rhodovulum viride JA756

Biofixation of CO2 is being extensively investigated to solve the global warming problem. Purple non-sulfur bacteria are fast growers that consume CO2 and produce beneficial biomass. Better the growth at higher CO2 levels, more efficient are the strains for biofixation. Nine among fifty strains that were analyzed at elevated CO2 levels responded with better growth. Considering its enhanced growth at high CO2 and metabolic versatility, Rhodovulum viride strain JA756 was chosen to make further studies. Strain JA756 tolerates up to 50% (v/v) CO2 with its optimum between 20–40% (v/v), yielding a biomass of 3.4 g. L−1. The pattern of specific enzyme activity of carbonic anhydrase corresponded well with that of its growth. To gain insights into the genomic composition and genes related to carbonic anhydrases and CO2 fixation, draft genome sequencing of JA756 was carried out which revealed the presence of two non-homologous genes encoding for β and γ carbonic anhydrases, both of which are assumed to be implicated in maintaining intracellular inorganic carbon concentration at equilibrium. Most of the genes involved in the Calvin pathway, reductive tricarboxylic acid pathway, 3-hydroxypropionate bicycle and C4 pathways were found in the draft genome. While the experimental determinations of active roles of two of these pathways are still underway, the expression of key genes of Calvin and C4 pathway suggest their functional role in the organism. Owing to its metabolic versatility, JA756 can be advantageous for biological CO2 assimilation facilities located by the coastline, inland and also at wide ranges of CO2 concentrations.

Symbiotic Efficiency of Slow and Fast-Growing Soybean Rhizobia of Central India

Soybean rhizobia are pre-dominantly slow growing but fast growing strains that evolved from natural populations have been reported globally including from several locations in India but have not been evaluated. The symbiotic effectivity of three slow and three fast-growing rhizobial strains isolated from Vertisols of Central India was evaluated on soybean var. 9752 in sterilized sand microcosms in a green-house. At 40 days growth, there was variation in nodulation parameters and growth of soybean with both types of rhizobia but overall, the slow growers were superior to fast growers with respect to nodule number (56%), nodule dry matter (25%), shoot dry matter (11%) and total nitrogen uptake (22%). The slow-growers (genetic homology to Bradyrhizobium japonicum) fixed ~ 25% more nitrogen than fast-growers with homology to Rhizobium (Agrobacterium) radiobacter. The results have very important implications for strain selection during biofertilizer production to maximize biological nitrogen fixation.

Mytilus galloprovincialis fast growing phenotypes under different restrictive feeding conditions: Fast feeders and energy savers

The present study aims to test if the environmental conditions prevailing during the growing period can determine the physiological profiles of specimens differentiated as fast (F) or slow (S) growers in the mussel Mytilus galloprovincialis. We reared mussel spats in the laboratory under two different conditions. In Treatment I (continuous feeding during discontinuous immersion), two mussel groups were submitted to a daily air exposure of 8 h and fed continuously during immersion-time, with either high-quality food dosed below the pseudofaeces threshold (BP group) or low organic content food dosed above the pseudofaeces threshold (AP group). In Treatment II (discontinuous feeding during continuous immersion), mussels were continuously immersed but fed only 1 day per week (RC group). Mussels were reared for 7 and 11 months (time required for size-differentiation) in Treatments I and II, respectively, and the smallest and largest individuals from each group were selected as S and F specimens.A series of feeding experiments (with different food quality, food ration and under continuous food supply) were performed to analyse the physiological performance of selected F and S mussels. In Treatment I, no significant differences were found in the metabolic rates between F and S mussels, and the faster growth rate of F-mussels resulted from their capacity to display higher clearance-ingestion rates and pre-ingestive selections. The physiological basis of growth rate differences between F and S mussels were found to be the same in mussels reared with diets below or above a pseudofaeces threshold (FBP, FAP, SBP and SAP). In contrast, the mussels from Treatment II had no significant differences in the feeding rates between FRC and SRC mussels. However, F individuals were found to have a 33% lower standard metabolic rate, indicating that fast growth under severe feeding restriction stemmed from a higher capacity of F-mussels to save energy during long periods of starvation. Despite the differences in the physiological basis explaining fast growth between the two treatments, F-mussels were found to possess significantly higher gill-surface area in both cases. It is thus concluded that endogenous factors affecting the gill-surface area play a major role in determining inter-individual growth rate differences in the mussel, Mytilus galloprovincialis.

English

A total of eighty one (81) rhizobial isolates were recovered from root nodules of cowpea (Vigna unguiculata L. Walp.) and groundnut (Arachis hypogaea L.) grown in soils collected from eight different sites (Hawassa, Wondogenet, Chofa, Badawacho, Bodity, Gofa, Ziway, and Alemtena) in Ethiopia with no known history of inoculation. The test isolates together with seven reference strains belonging to five genera including Rhizobium, Ensifer, Mesorhizobium, Bradyrhizobium and Azorhizobium were characterized using ninety phenotypic traits. Thirty one isolates (38%) were found to be fast growers while fifty isolates (62%) were slow growers. The majority of the isolates showed an intrinsic resistance to antibiotics (µg/ml), Chloramphenicol (5 and 15), Lincomycin (100), Novobiocin (0.5 and 1.5), and Erythromycin (10 and 20) and to heavy metals manganese sulphate (500) and copper chloride (100). Most isolates did not tolerate NaCl concentration >3% (w/v) and high temperature (45°C). Dendrogram was constructed by applying the unweighted pair group method with arithmetic means (UPGMA) using NTSYSpc Version 2.1. They were grouped into seven clusters and eight unclustered positions, when 82% relative similarity was used as a cut point. Fifty eight percent of the test isolates were grouped with Bradyrhizobium japonicum and Bradyrhizobium elkanii superclades, thus indicating that rhizobia nodulating cowpea and groundnut are delineated within a branch that defines Bradyrhizobium genus. To elucidate the precise taxonomic positions of the isolates, further genetic studies are required using modern molecular biological methods. Key words: Groundnut, cowpea, isolates, phenotypic traits, Bradyrhizobium, Rhizobium.

Behavioral indicators of slow growth in nursery pigs

ABSTRACTThe objective of this study was to determine how feeder-space allowance affects behaviors of slow- and fast-growing pigs during the nursery period. Nursery pigs (n = 192; initial weight = 7.4 ± 1.6 kg) were housed in 24 pens of 8 pigs, with 12 pens provided with either a two-space feeder or a five-space feeder. Pigs were categorized as slow growers (SG) and fast growers (FG) based on adjusted market weight (SG < 105 kg; FG ≥ 105 kg). Behaviors of pigs were video-recorded during the first four days after entering the nursery and on Day 21. Eating speed was measured on 96 focal pigs when they were nine weeks old. SG spent more time at the drinker than did FG (p < .05). SG spent less time in the standing/walking posture (p < .05) in pens with five-space feeders compared with SG in pens with two-space feeders. These results suggest that providing more feeder space may benefit SG in terms of improving the welfare of these pigs.

Selection of Yeast Strains for Tequila Fermentation Based on Growth Dynamics in Combined Fructose and Ethanol Media.

A method to select yeast strains for fermentation taking into account the natural differences of yeast isolates. This methodology is based on the cell exposition to combinations of sugar and ethanol, which are the most important stress factors in fermentation. This strategy will help to identify the most tolerant strain that could improve ethanol yield and reduce fermentation time.

PknG supports mycobacterial adaptation in acidic environment.

Mycobacterium tuberculosis (Mtb), causative agent of human tuberculosis (TB), has the remarkable ability to adapt to the hostile environment inside host cells. Eleven eukaryotic like serine-threonine protein kinases (STPKs) are present in Mtb. Protein kinase G (PknG) has been shown to promote mycobacterial survival inside host cells. A homolog of PknG is also present in Mycobacterium smegmatis (MS), a fast grower, non-pathogenic mycobacterium. In the present study, we have analyzed the role of PknG in mycobacteria during exposure to acidic environment. Expression of pknG in MS was decreased in acidic medium. Recombinant MS ectopically expressing pknG (MS-G) showed higher growth in acidic medium compared to wild type counterpart. MS-G also showed higher resistance upon exposure to 3.0 pH and better adaptability to acidic pH. Western blot analysis showed differential threonine but not serine phosphorylation of cellular proteins in MS at acidic pH which was restored by ectopic expression of pknG in MS. In Mtb H37Ra (Mtb-Ra), expression of pknG was increased at acidic pH. We also observed decreased expression of pknG in MS during infection in macrophages while the expression of pknG in Mtb-Ra was increased in similar conditions. Taken together, our data strongly suggests that pknG regulates growth of mycobacteria in acidic environment and is differentially transcribed in MS and Mtb under these conditions.

Screening of Fungi Capable of Degrading Lignin from Decaying Woods in Dry and Intermediate Zone Forests of Sri Lanka

Lignin is the third main constituent in wood and is a complex macromolecule formed by the polymerization of three phenylpropane monomers. It is resistant to degradation due to its phenyl propane monomers in the structure and the recalcitrant linkages between them. Therefore, finding microorganisms capable of breaking down lignin is of great interest in biotechnological research specially in biofuel technology. This research was initiated with the aim of isolating strong lignin degraders from the decaying wood pieces obtained from the dry and intermediate zone forests. It was hypothesized that the fungal species found in dry and intermediate zone forests are strong lignin degraders since these forests are rich in hard wood bearing plant species. White rot fungi were isolated into pure cultures from decaying wood pieces showing white rot symptoms on hard wood pieces. In addition, fungal fruiting bodies were also selected whenever possible. Total of 35 pure fungal cultures were isolated and used for further analysis. Each isolate was grown on minimal agar amended with wood powder (mango+burutha powder in 1:1 ratio) and colony diameter was measured after 3 days. Three class of growths, fast growers (6-9 cm), intermediate growers (3-6 cm) and slow growers (0-3 cm), were tentatively identified based on their colony diameter on wood agar media after three days. Twelve were fast growers, 5 were intermediate growers and the rest were slow growers. Since laccase is one of the important enzymes required for the lignin degradation, the ability to produce laccases by these fungi was estimated by observing the ability to change the color on guaiacol amended PDA. Only three out of 12 fast growers and 4 out of 5 intermediate growers were able to change the color on guaiacol containing media indicating that these isolates were potential wood decaying fungal species with the ability of laccase production. Most of the strong guaiacol producers were basidiomycetes and isolate characterization is being carried out using molecular and morphological methods. Keywords: Lignin degrading, Dry zone forest, Wood decay, White root fungi

Mycobacterial DNA-binding protein 1 is critical for long term survival of Mycobacterium smegmatis and simultaneously coordinates cellular functions

Bacteria can proliferate perpetually without ageing, but they also face conditions where they must persist. Mycobacteria can survive for a long period. This state appears during mycobacterial diseases such as tuberculosis and leprosy, which are chronic and develop after long-term persistent infections. However, the fundamental mechanisms of the long-term living of mycobacteria are unknown. Every Mycobacterium species expresses Mycobacterial DNA-binding protein 1 (MDP1), a histone-like nucleoid associated protein. Mycobacterium smegmatis is a saprophytic fast grower and used as a model of mycobacterial persistence, since it shares the characteristics of the long-term survival observed in pathogenic mycobacteria. Here we show that MDP1-deficient M. smegmatis dies more rapidly than the parental strain after entering stationary phase. Proteomic analyses revealed 21 upregulated proteins with more than 3-fold in MDP1-deficient strain, including DnaA, a replication initiator, NDH, a NADH dehydrogenase that catalyzes downhill electron transfer, Fas1, a critical fatty acid synthase, and antioxidants such as AhpC and KatG. Biochemical analyses showed elevated levels of DNA and ATP syntheses, a decreased NADH/NAD+ ratio, and a loss of resistance to oxidative stress in the MDP1-knockout strain. This study suggests the importance of MDP1-dependent simultaneous control of the cellular functions in the long-term survival of mycobacteria.

A Protocol to Map Vine Size in Commercial Single High-Wire Trellis Vineyards Using “Off-the-Shelf” Proximal Canopy-Sensing Systems

Summary Goals: This report aims to present a clear protocol for (a) deploying proximal canopy sensors into single high-wire trellis Concord ( Vitis labruscana cv. Bailey) vineyards and (b) converting the canopy sensor response into an indication of vine size (pruning weight). The protocol is designed to be robust and practical for easy adoption in commercial systems. Evidence will be presented of the efficacy of vine size prediction using the protocol in multiple research and commercial vineyards. Key Findings: Using different vineyards and pruning crews, the protocol performed well in >80% of vineyards and permitted growers to generate maps of actual vine size within vineyards. These maps provide a valuable indication of current site-specific production potential and a baseline to assess changes in vine size over time. In a few vineyards, the proposed simplified calibration process did not generate a clear relationship between canopy response and vine size, which may be due to changes in vine shape in highly mechanized systems. Impact and Significance: Managing vine size is critical to the long-term sustainability of cool climate viticulture and to managing quality in all viticulture systems. However, convincing growers to routinely measure vine size for more effective management has been difficult historically because of the time involved and the difficulty of translating the data into a decision process. The proposed protocol uses technology and targeted sampling to minimize the effort required, and presents more coherent information that allows fast grower responses. Grower adoption of this protocol should promote continual vine size measurement, with the goal of decreasing vine size variation within vineyards.

Tolerance to herbivory and the resource availability hypothesis.

The resource availability hypothesis (RAH), the most successful theory explaining plant defence patterns, predicts that defence investment is related to the relative growth rate (RGR) of plant species, which is associated with habitat quality. Thus, fast-growing species should show lower resistance than slow-growing species, which would lead fast growers to sustain higher herbivory rates, but the fitness consequences of herbivory would be greater for slow growers. The latter is often assumed but rarely tested. In a temperate rainforest, we tested the expected pattern of tolerance to herbivory derived from the RAH: that fast-growing species should be more tolerant than slow-growing species. We also evaluated whether other plant features covary with RGR (leaf lifespan, shade tolerance and leaf toughness) and thus could also contribute to the patterns of tolerance to herbivory. As expected, seedlings from tree species with higher RGR showed greater tolerance to herbivory. Among the three plant features included, only leaf lifespan showed a significant association with RGR, but RGR was the best predictor of tolerance. We argue that plant tolerance to herbivory must be evaluated to properly verify the assumptions of the RAH.

Phenotyping Groundnut Rhizobia Native to Phosphorus Deficient Soils in Western Kenya

Most soils in western Kenya are characterized by high acidity level and phosphorus (P) deficiency, which affect nodulation and nitrogen fixation of groundnut (Arachis hypogaea L.). This study aimed at characterising rhizobia capable of nodulating groundnut in P deficient soils in Western Kenya. Sixty four isolates out of the 68 were confirmed to be rhizobia due to their ability to nodulate groundnut. Ninety six percent of the isolates exhibited semi-globose to globose colony shape on yeast extract mannitol agar (YEMA). Groundnut was nodulated by both fast and slow growing rhizobia isolates with 81% being fast growers. Fifty one isolates representing 75% produced acid on YEMA medium supplemented with bromothymol blue (BTB). The isolates varied in their response to pH with 39 and 61 growing at pH 4.0 and 5.5, respectively. All the isolates grew at pH 7.0 and 8.5. YEMA medium containing glucose, sucrose, starch and citrate had 64, 61, 56 and 5 isolates growing, respectively. Sixty four isolates exhibited clear zone of solubilization on medium containing dicalcium phosphate as source of inorganic phosphate. Solubilization index (SI) varied from 1.1 to 6.8. Fast-growing rhizobia isolates N01, B02, I06, Q01, F05, C02, E01, Q03, I01 and B01 recorded the highest solubilization index of 3.8, 4.5, 4.6, 4.6, 4.7, 5.0, 5.1, 6.1, 6.1 and 6.8, respectively. Groundnut rhizobia showed variation in their potential to solubilize inorganic phosphate and effectively nodulate the host. The most promising isolates from this study would be used as bio-fertilizer upon further validation in the greenhouse and field.

Population ecology of soybean-rhizobia in diverse crop rotations in Central India

Ensuring adequate populations of effective rhizobia in soil is essential to guarantee optimum nodulation and nitrogen fixation in legumes. The population of soybean-rhizobia and the proportion of slow and fast growers were enumerated in Vertisols of central India in different crop rotations for three years during 2013-15. Soils were from soybean-based (soybean-wheat and soybean-chickpea) and cereal-based rotations (maize-wheat, rice-wheat and maize-chickpea) rotations. Soybean-based rotations stimulated the rhizobial population by 22-fold compared to cereal rotations. Lowest populations were in the summer but increased in soybean rotations by 13.3-fold after the rainy season to 2743cellsg−1 soil at maximum vegetative growth. In the cereal rotations, the increase was by 1.7-fold to 61cellsg−1 soil. Long-term integrated nutrient management, by annual application of farmyard manure in soybean along with chemical fertilizers, improved the rhizobial numbers by 1.5-fold over chemical fertilization alone and by 2.9-fold over unfertilized treatments. Increased crop growth by chemical fertilizers also stimulated rhizobial populations by 1.9-fold over unfertilized soybean. The proportion of slow-growing soybean rhizobia was lower in soybean-based rotations (38%) compared to cereal-based rotations (62%), showing that continued soybean growth led to a greater proliferation of fast-growing rhizobia. Application of farmyard manure did not change the proportion of slow growers. The proportion of slow growers was ∼15% more in winter compared with the summer populations. The slow growers were symbiotically superior, producing greater dry matter and nodule mass (+12%), with more biologically fixed nitrogen (+18%) than the fast growers. Results highlight the importance of crop rotation with cereals, application of organic amendments along with chemical fertilizers and selection of slow-growing rhizobia as inoculants.

The Proximity of Ribosomal Protein Genes to oriC Enhances Vibrio cholerae Fitness in the Absence of Multifork Replication.

ABSTRACTRecent works suggest that bacterial gene order links chromosome structure to cell homeostasis. Comparative genomics showed that, in fast-growing bacteria, ribosomal protein genes (RP) locate near the replication origin (oriC). We recently showed that Vibrio cholerae employs this positional bias as a growth optimization strategy: under fast-growth conditions, multifork replication increases RP dosage and expression. However, RP location may provide advantages in a dosage-independent manner: for example, the physical proximity of the many ribosomal components, in the context of a crowded cytoplasm, may favor ribosome biogenesis. To uncover putative dosage-independent effects, we studied isogenic V. cholerae derivatives in which the major RP locus, S10-spc-α (S10), was relocated to alternative genomic positions. When bacteria grew fast, bacterial fitness was reduced according to the S10 relative distance to oriC. The growth of wild-type V. cholerae could not be improved by additional copies of the locus, suggesting a physiologically optimized genomic location. Slow growth is expected to uncouple RP position from dosage, since multifork replication does not occur. Under these conditions, we detected a fitness impairment when S10 was far from oriC. Deep sequencing followed by marker frequency analysis in the absence of multifork replication revealed an up to 30% S10 dosage reduction associated with its relocation that closely correlated with fitness alterations. Hence, the impact of S10 location goes beyond a growth optimization strategy during feast periods. RP location may be important during the whole life cycle of this pathogen.

Rapid growth causes abnormal vaterite formation in farmed fish otoliths.

Sagittal otoliths are essential components of the sensory organs that enable all teleost fish to hear and maintain balance, and are primarily composed of calcium carbonate. A deformity, where aragonite (the normal crystal form) is replaced with vaterite, was first noted over 50 years ago but its underlying cause is unresolved. We evaluated the prevalence of vateritic otoliths from two captive rearing studies which suggested that fast growth, due to environmental rather than genetic control, led to vaterite development. We then tested this by varying light and temperature to create phenotypes with different growth rates, which resulted in fast growers (5times larger) having 3times more vaterite than slow growers. A decrease in either the ratio of otolith matrix proteins (otolin-1/OMM-64) or [Ca2+]/[CO32-] may explain why fast growth causes vaterite deposition. As vaterite decreases hearing sensitivity, reducing growth rates in hatcheries may improve the welfare of farmed fish and increase the success of conservation efforts.

Shoot and root responses of woody species to silvicultural management for afforestation of degraded croplands in the Sudano-Sahelian zone of Benin

In the Sudano-Sahelian zone of West Africa, where deforestation and cropland soil degradation occur at alarming rates, the (re-)introduction of trees on degraded lands can improve and sustain farming systems and landscapes. The shoot and root morphological traits of five woody species introduced to degraded cropland were assessed with a particular focus on the survival, early establishment and growth of saplings subjected to manuring (1kg per plant) and drip irrigation (0.5L of water per plant per day). Functional traits of the woody above- and belowground organs of field-grown plants were monitored for the first 15months after planting, covering two growing (rainy) seasons and one dry season. The high survival rate (>60%), combined with a very low incidence rate (<1%), for all species was evidence of successful establishment overall. The highest survival rates (94–100%) were observed in Jatropha curcas L., Leucaena leucocephala Lam. and Moringa oleifera Lam. The mortality rate of the most drought-sensitive species Parkia biglobosa Jacq. could be reduced ten-fold through supplemental irrigation during the dry season. The fast-growing L. leucocephala, M. oleifera and J. curcas had higher values for shoot-level traits than did the slow-growing Anacardium occidentale L. and P. biglobosa. Fertilization and irrigation enhanced the shoot growth of both the fast and slow growers during the dry and growing seasons. In contrast, belowground development was either increased or reduced by fertilization and irrigation during the growing and dry seasons, but the slow growers demonstrated a more plastic response to these treatments than did the fast growers. Among the studied traits, the relative growth rate of plant as a whole (i.e. shoots and roots combined) exhibited the greatest plastic response to resource availability, thus suggesting its application in screening candidate species for afforestation efforts. Overall, the five studied species were considered suitable for the afforestation of degraded croplands, while the early growth and establishment of saplings could be boosted by irrigation and a supply of manure.

Location of leisure: the New Economic Geography of leisure services

Understanding more about the geographic location of leisure services is an important quest for research. For a long time now in developed economies, almost all employment growth is occurring within the service sector. In this sector, leisure services are fast growers. This means that the location of these services is important for economic growth and for employment opportunities of local market areas. Regional policy-makers time and again highlight these sectors as future engines of growth. This paper investigates the role of local demand in determining the availability and the scale of various types of leisure services. The analysis is motivated by observed regularities that indicate large and persistent interregional differences in the location and growth of leisure services. Based on a New Economic Geography framework, we investigate the role of local and regional demand for the size of leisure services in geographically separate markets in Sweden. We use data for 290 Swedish municipalities for the period 2002–2013 and run year-municipality fixed-effects regressions. Our main findings suggest a strong dependency on local demand, and less on the demand originating from other regions.

Physiological basis of metabolic trade-offs between growth and performance among different strains of rainbow trout

Adaptive trade-offs define the trait combinations that differentiate taxa and allow coexistence along environmental gradients. To understand the physiological trade-offs associated with growth, we examined relationships among metabolic rate, digestive capacity, tissue energy content, and growth in juveniles of three strains of rainbow trout (Oncorhynchus mykiss) that differ in growth. Fish were reared under satiation, 1% of body mass per day, and complete food deprivation treatments to assess differences in performance and adaptive trade-offs along a gradient of resource availability. The fast-growing hatchery strain had higher standard metabolic rate (SMR), lower aerobic scope, and potentially lower maximum metabolic rates, suggesting that high growth trades off against a reduced capacity to do metabolic work. Trout with high growth rates also generally had larger gastrointestinal tracts, maximum food consumption, and growth efficiency. Results demonstrate (i) higher SMR of fast growers appears to be related to a greater investment in high-maintenance digestive tissue that supports rapid growth; (ii) growth appears to trade off against active metabolism; and (iii) selection on growth involves a suite of integrated physiological and anatomical traits that are affected by both genotype and environment (ration).