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Number of results: 15
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Abstract

Horns, teeth, claws, beaks… Given this mighty arsenal it’s a wonder there isn’t more physical conflict in the animal world, such as among birds.
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Abstract

Antarctic krill carbohydrate content was followed during 1983—84 Eighth Polish Antarctic Expedition. The Admiralty Bay (King George Island) was th area of study. The following average values of three estimated fractions were obtained: 3.77 +- 1.51%, 0.47 +- 0.34% and 3.30 +- 1.33% for total, TCA-soluble and TCA-insoluble carbohydrates, respectively. Percentage contribution of the estimated fractions to dry weight varied seasonally (1.48—7.41%, 0.15—1.83%, and 1.28—6.28%, respectively). The carbohydrate content showed a clearcut cycle of changes over the calender year, with a minimum in autumn-winter and a maximum in spring-summer.
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Abstract

Seasonal changes in the Antarctic krill (Euphausia superba Dana) autoproteolytic activity were followed throughout the year. Using the kinetic formula for the first order reaction, the initial reaction rate (y0), the rate after 5 minutes (y5) and the average reaction rate (yx) after 0, 5, 10, 15 and 20 min of incubation of mixed homogenate at 40° + 0.2°C were determined in each sample. Changes in the krill autoproteolytic activity over the year were found to follow a sinusoid with a maximum during the austral summer (January) and a minimum during the austral winter (July-August). The maximum initial reaction rate was about ten times the minimum initial rate, which is an evidence of a considerable seasonal variation in the krill autoproteolytic activity associated presumably with the krill feeding intensity.
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Abstract

Notothenia coriiceps, N.rossii and Lepidonotothen nudifrons were sampled from Admiralty Bay from March to November 1997 and from January to February 1999. The ratio of N.coriiceps to N.rossii individuals in catches regularly increased during 22 years from 0.4 in 1977 to 9.5 in 1999. Oving to its reproductive strategy and avoidance of shallow waters N.rossii may be more vulnerable to overfishing. The condition factor was the most stable (CV 6 -10%), variations in the of hepatosomatic index and index of stomach fullness were intermediate (21 -38%and 40 -43%,respectively), and the gonadosomatic index was the most variable (65 -100%). Lack of seasonality in two somatic indices (condition factor and index of stomach fullness) in N.coriiceps adults is a direct effect of high food availability and unlimited food detection all year round. In contrast, the seasonality of a reproductive index (gonadosomatic index) of these fish is a response to the highly seasonal trophic conditions for pelagic larvae.
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Abstract

The aim of the research conducted in a 2-year pot experiment in an unheated plastic tunnel was to determine suitability of Miscanthus × giganteus for phytoextraction of nickel from soil as well as to assess tolerance of this species on increasing concentrations of this metal in soil. Pots were filled with mineral soil (sand) and a mixture of soil with high-moor peat and three levels of nickel were introduced, i.e. 75 mg dm-3, 150 mg dm-3 and 600 mg dm-3 and the control combinations used substrates without the addition of nickel. Nickel was introduced only in the first year of the experiment in the form of nickel sulfate (NiSO4 · 6H2O). Miscanthus × giganteus accumulated a considerable amount of nickel in biomass. Miscanthus × giganteus growing in contaminated mineral soil turned out to be a species tolerant to high nickel concentrations
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Abstract

It is meaningful to study the issues of CO migration and its concentration distribution in a blind gallery to provide a basis for CO monitoring and calculation of fume-drainage time, which is of a great significance to prevent fume-poisoning accidents and improve efficiency of an excavation cycle. Based on a theoretical analysis of a differential change of CO mass concentration and the CO dispersion model in a fixed site, this paper presents several blasting fume monitoring test experiments, carried out with the test location to the head LP in arrange of 40-140 m. Studies have been done by arranging multiple sensors in the arch cross-section of the blind gallery, located at the Guilaizhuang Gold Mine, Shandong Province, China. The findings indicate that CO concentrations in the axial directions are quadratic functions with the Y and Z coordinate values of the cross-section of the blind gallery in an ascending stage of CO time- -concentration curve, with the maximum CO concentrations in Y = 150 cm and Z = 150 cm. Also, the gradients of CO concentration in the gallery are symmetrical with the Y = 150 cm and Z = 150 cm. In the descending stage of CO time-concentration curve, gradients of CO concentration decrease in lateral sides and increase in the middle, then gradually decrease at last. The rules of CO concentration distribution in the cross-section are that airflow triggers the turbulent change of the CO distribution volume concentration and make the CO volume concentration even gradually in the fixed position of the gallery. Moreover, the CO volume concentrations decrease gradually, as well as volume concentration gradients in the cross-section. The uniformity coefficients of CO concentration with duct airflow velocities of 12.5 m/s, 17.7 m/s and 23.2 m/s reach near 0.9 at 100-140 m from the heading to the monitoring spot. The theoretical model of a one-dimensional migration law of CO basically coincides with the negative exponential decay, which is verified via fitting. The average effective turbulent diffusion coefficient of CO in the blind gallery is approximate to 0.108 m2/s. There are strong linear relationships between CO initial concentration, CO peak concentrations and mass of explosive agent, which indicates that the CO initial concentration and the CO peak concentration can be predicted, based on the given range of the charging mass. The above findings can provide reliable references to the selection, installation of CO sensors and prediction of the fume-drainage time after blasting.
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Abstract

The aim of this study was to compare the efficacy of estrus induction and fertility by using subcutaneous melatonin (MEL, T1) and short-term intravaginal medroxyprogesteronacetate plus pregnant mare serum gonadotropin treatments (sMAP+eCG, T2) in ewes on seasonaly anestrus. In this study, 105 mature clinically healthy Kivircik ewes in anestrus season and 4 rams were used. After synchronization applications, ewes exhibiting estrus signs were hand-mated with rams known to be fertile. Blood samples were collected at different times in order to determine progesterone (P4) concentrations. Results showed that estrus manipulation protocols induced significant improvement in pregnancy rate. All the fertility results obtained with the sMAP+eCG or MEL groups were similar, in seasonal anestrus. The efficacy duration of P4 in the MEL group was longer than that in short-term progestagen group. Plasma P4 concentrations was significantly different between the first (I) and last (III) measurement days (p<0.01). Increase in P4 concentration in T2 group was faster than that in T1 group, and blood P4 concentrations at higher levels could successfully be achieved by using any of the protocols in this study during the seasonal anestrus. In conclusion, according to the results obtained, the hormone application groups received very high estrus response. In addition, the twin ratio was found to be higher in T1 group compared to those determined in the other groups (T2 and Control group). Furthermore, plasma P4 concentrations and high birth rates were obtained in ewes in T1 and T2 groups. These procedures can be considered a good alternative to traditional procedures due to its flexibility under field conditions.
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Abstract

Measurements were made of organic fluxes at a coastal sediment at Signy Island , South Orkney Islands, Antarctica , between December 1990 and March 1992. The deposition rate of organic matter to the sediment was measured at the same time with a maximum sedimentation rate of 306 mg C m–2 d–1. The rates of sedimentary organic input were small during winter ice cover, and the organic content of the sediment declined during this period as available organic matter was depleted. Fresh organic input occurred as soon as the sea-ice melted and ice algal biomass was deposited to the sediment; and was sustained during the spring after ice break-up by continued primary production in the water column. The proportion of available carbon in surface sediments was measured during a seasonal cycle using Pseudomonas aeruginosa as an indicator organism over the 0–1 cm depth horizon. Variations in the amount of organic matter deposited to the sediments and the proportion of available carbon were observed during the seasonal cycle. Seasonal variations of benthic activity in this coastal sediment was regulated by the input and availability of organic matter, and not by seasonal water temperature, which was relatively constant between –1.8 and 0.5°C .
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Abstract

Ground temperature variations have been analysed to the depth of 160 cm, with respect to meteorological elements and short-wave radiation balance. The database of the ground temperature covers a thirteen month-long period (May 1992 – June 1993), which included both the seasons of complete freezing of the ground and thaw. Special attention has been given to the development of perennial permafrost and its spatial distribution. In summer, the depth of thawing ground varied in different types of ground — at the Polish Polar Station, this was ca. 130 cm. The ground froze completely in the first week of October. Its thawing started in June. The snow cover restrained heat penetration in the ground, which hindered the ground thawing process. Cross-correlation shows a significant influence of the radiation balance (K*) on the values of near-surface ground temperatures (r2 = 0.62 for summer).
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Abstract

Bayesian VAR (BVAR) models offer a practical solution to the parameter proliferation concerns as they allow to introduce a priori information on seasonality and persistence of inflation in a multivariate framework. We investigate alternative prior specifications in the case of time series with a clear seasonal pattern. In the empirical part we forecast the monthly headline inflation in the Polish economy over the period 2011‒2014 employing two popular BVAR frameworks: a steady-state reduced-form BVAR and just-identified structural BVAR model. To evaluate the forecast performance we use the pseudo real-time vintages of timely information from consumer and financial markets. We compare different models in terms of both point and density forecasts. Using formal testing procedure for density-based scores we provide the empirical evidence of superiority of the steady-state BVAR specifications with tight seasonal priors.
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Abstract

This article aims at constructing a new method for testing the statistical significance of seasonal fluctuations for non-stationary processes. The constructed test is based on a method of subsampling and on the spectral theory of Almost Periodically Correlated (APC) time series. In the article we consider an equation of a nonstationary process, containing a component which includes seasonal fluctuations and business cycle fluctuations, both described by an almost periodic function. We build subsampling test justifying the significance of frequencies obtained from the Fourier representation of the unconditional expectation of the process. The empirical usefulness of the constructed test is examined for selected macroeconomic data. The article studies survey indicators of economic climate in industry, retail trade and consumption for European countries.
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