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1. The effects of changes in technical efficiency on the increase of broiler production are presented for the period 1994–2013 based on the panel data from seven farms located in southern and central Poland. A total of 766 cycles were analysed.

2. The Cobb–Douglas production function was used to assess the changes of output elasticities as well as technical changes in broiler production, for 5-year sub-periods separately.

3. Technical indices of broiler production significantly improved between years 1994–2013: feed conversion ratio decreased from 2.50 kg/kg to 1.78 kg/kg, mortality rate from 8.8% to 4.0% and daily weight gain increased from 37.1 g/d to 58.7 g/d, respectively.

4. Before accession to the EU, there was a substantial increase of fixed capital connected with modernisation of buildings and equipment. In the period 1994–2013, inputs of fixed capital per kilogram of livestock increased by 72% and at the same time the input of labour decreased by 56%.

5. Technical changes in years 1994–1998 contributed to a rapid production increase at a rate of 4.6% annually and only by up to 0.7% annually during 2009–2013. The slowdown of production rate increase after 2009 was partially caused by decreasing the stocking density.  相似文献   

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The aim of this article was to analyse the process of pikeperch, Sander lucioperca, egg swelling and to apply tannic acid to eliminate egg stickiness at different moments of the swelling process on artificially obtained eggs. The first experiment involved observation of egg swelling process and the second determined the effect of temperature (12, 14 and 16°C) on the egg swelling rate. The third experiment involved elimination of egg stickiness in a tannin solution (0.75 g L?1) where eggs were submerged in a solution for 0.5, 1, 2 and 5 min – 5, 10, 15, 20, 25 and 30 min following gamete activation. The results indicate that the pikeperch egg swelling process lasts 30 min. It was found that the temperature did not affect the process duration. The results of the third experiment showed that the effectiveness of tannic acid application in egg stickiness elimination increases with time. The best result was obtained in groups of eggs submerged for 1 and 2 min (86.5% and 80.5% of larvae were obtained respectively) 30 min following the gamete activation. The results presented in this study for the first time indicate the possibility of highly effective procedure of egg stickiness elimination with tannic acid in pikeperch aquaculture.  相似文献   
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Predictions of future climate change include shifts in patterns of precipitation, evapotranspiration and water run‐off, resulting in increased periods of drought as well as variability and intensity of rainfall events. In the United Kingdom, the non‐native North American sunfish, pumpkinseed Lepomis gibbosus (L.), is expected to benefit from these changes. We examine how hydrological variability induced by predicted changes in climate will affect the dispersal and spread of pumpkinseed in England by: (i) determining the relationship between discharge regime and pumpkinseed propagule pressure; (ii) examining a newly‐established pumpkinseed population following a flood event in 2007; and (iii) comparing the growth and life‐history traits of this new population with fish collected from the source population to demonstrate how the pumpkinseed's life‐history plasticity contributes to its success as a coloniser. Using Bayesian modelling, we determined that the number of pumpkinseed escapees is likely to increase with increasing discharge. The newly‐established pumpkinseed population showed fast juvenile growth, early age at maturity and small size at maturity. These traits differed significantly from the source population, specifically total length (TL) means at ages 1 and 2 were significantly greater in the new population, whereas TL at age 4 was significantly greater in the source population, and a significantly higher proportion of mature females were found at smaller size classes in the newly established pumpkinseed population. This study demonstrates the potential link between hydrological variability (current and future) and the dispersal of non‐native pumpkinseed, leading to the establishment of new populations.  相似文献   
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A previously unknown association of ants with birds breeding in tree holes is described. Ants Lasius brunneus Latreille (Hymenoptera: Formicidae) were found in c. 15% of nests of Parus major L. and Poecile palustris L. (Paridae) breeding in tree holes in the primeval deciduous forest located in the Bia?owie?a National Park (Poland). The ants preferably used holes located higher above the ground. As such holes are warmer than the unused holes or other nest sites, it is suggested that the ants cohabit holes utilized by the tits to gain thermal benefits.  相似文献   
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This study describes the distribution of galanin (Gal) and galanin receptor 2 (GalR2) in the pre‐optic area (POA) of the female guinea pig. Frozen sections were undergone for a routine immunofluorescence labelling. Gal and GalR2 display immunoreactivity in all parts of the pre‐optic area. Gal shows reactivity both in perikarya and fibres, whereas GalR2 was observed only in perikarya. Gal‐ and GalR2‐immunoreactive (‐ir) perikarya were the most numerous in the medial pre‐optic area (MPA) with the highest reactivity in its dorsal part. In the median pre‐optic nucleus (MPN) and periventricular pre‐optic nucleus (PPN), only single Gal‐ and GalR2‐ir neurons were observed. The highest density of Gal‐ir fibres was revealed in the PPN and the lowest in the lateral pre‐optic area (LPA). The results of this study indicate that the distribution pattern of Gal containing neurons overlaps well with the distribution pattern of GalR2‐positive neurons, especially in the MPA. This may suggest GalR2‐dependent activity in this brain region.  相似文献   
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New Forests - Forest tree seedling production technologies impact reforestation success determined with survival and quality of seedlings. Five Abies alba seedling production technologies were...  相似文献   
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Summary Fruit size is one of the most important characteristics of highly productive strawberry cultivars. The aim of the experiments was to establish the factors responsible for the expression of this trait. The total yield of large fruits correlates closely with the total yield of all fruits and depends mainly on the mean fruit weight of all fruits. The position of fruits on the inflorescence influences the decline of fruit size to a larger extent in small-fruited clones than in the large-fruited ones. The size of the fruit is controlled by the dimension of the receptacle and number of achenes. The stimulating effects of achenes are quite different in various genotypes and the fruit weight per achene declines with the inferior blossom position. The large-fruited clones have bigger leaves, a larger photosynthetic area, and thicker petioles and flower stalks. Their cells are larger, which is common for the giant genotypes. The results suggest that there exists a possibility for indirect selection of fruit size on the basis of some additional parameters, which can be useful particularily in the years of unsuitable weather conditions.  相似文献   
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The PPR‐B gene is responsible for male‐fertility restoration of the Ogura‐type male‐sterile radish plants, and it is located in the complex Rfo locus in the vicinity of similar PPR‐A gene and PPR‐C pseudogene. The aim of this study was to identify PPR‐B alleles and understand the structure of the Rfo locus in radish breeding lines. Five lines of radish with normal male‐fertile cytoplasm were tested. The entire PPR‐B gene was amplified, sequenced and allelic PPR‐B sequences were identified. The results indicated that the maintainer lines 7, 15 and 21 contained a non‐restoring form of PPR‐B protein. A unique PPR‐B was found in lines 24/15 and 31 that are restorer and maintainer lines, respectively. The substitutions might be responsible for the loss of a restoring function of the PPR‐B‐31 allele. Amplification of the PPR‐A/PPR‐B and PPR‐B/PPR‐C intergenic regions allowed to identify rearrangements within Rfo locus. Obtained results confirm the wide allelic variation within the Rfo locus, as well as high genetic complexity of the fertility restoration mechanism in radish.  相似文献   
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