A field trial was conducted to examine the effect of extended calving interval (CI) on production and profitability of high yielding cows (n = 937). First insemination was performed at 154 and 93 d ...postpartum (pp), for treatment and control primiparous cows, respectively, and at 124 and 71 d pp for treatment and control multiparous cows, respectively. During the first experimental lactation, average daily value-corrected milk (VCM) yield was 28.5 and 27.7 kg/d of CI for treatment (n = 131) and control (n = 133) primiparous cows, respectively. No significant difference in average daily VCM yield (33.0 and 32.8 kg/d of CI) was found between treatment (n = 271) and control (n = 215) multiparous cows . In the first 150 d of the subsequent lactation, there were significant differences in milk and VCM production in favor of the treatment primiparous cows (41.4 vs. 39.7 kg of VCM/d) but no significant differences in the production of multiparous cows. Primiparous and multiparous cows with extended lactations were more profitable. During the first experimental lactation, there were advantages of $0.19 and $0.12/d of CI in the net returns for primiparous cows and multiparous cows with longer CI, respectively. When the economic analysis included the first experimental lactation plus the first 150 d of the subsequent one, the net return per day of CI was higher for cows with an extended voluntary waiting period: $0.21/d and $0.16/d for primiparous and multiparous cows, respectively. A delay of 60 d with respect to the usual voluntary waiting period in the beginning of inseminations of high yielding cows has economic advantages and allows the farmer an option for decisions regarding individual cows.
The 10Be/9Be ratios in marine sediments samples from the Southern Chile Trench have been measured using accelerator mass spectrometry (AMS). The samples were measured at the TANDAR accelerator, where ...the discrimination of the 10Be radionuclides was achieved by means of a passive absorber in front of an ionization chamber. This setup along with the high voltage available, provided a complete suppression of the 10B isobar interference. The obtained values for the 10Be concentrations, of the order of 109atoms/g, are the first 10Be measurements from the Southern Chile Trench and offer an excellent tracer to quantitatively study the recycling of sediments in Andean magmas.
The objectives of this study were to identify and evaluate production and environmental factors that influence milk urea (MU) in Israeli dairy herds, to analyze the relationships between MU ...concentration and nutritional variables, and to examine a possible association between MU and pregnancy rate (PR). Production and environmental data were obtained from the Israeli Dairy Herd Improvement (DHI) Center (n=1,279,600). Programmed total mixed rations (feeds and quantities) on milk-test day were collected from 42 dairy herds. Data on 36,073 cows that were inseminated close to milk-test day and pregnancy diagnosis results were obtained from the DHI data bank. Highly significant positive relationships were found between MU concentration and milk yield and fat percentage; relationships between MU and milk total protein percentage and somatic cell count were negative. Milk urea levels were higher during the summer months and were higher for adult cows. These levels increased as lactation progressed. Milk urea was positively associated with dietary levels of crude protein, ruminal digestible protein, and neutral detergent fiber contents; it was negatively associated with ration energy and nonstructural carbohydrate contents. Significant influences of specific feeds on MU were detected. A significant negative association was found between MU level and PR. Least squares means for PR for cows in the lowest and highest MU quartiles were 38.4 and 36.1%, respectively. Increasing levels of MU were negatively related to reproductive performance of dairy cows, but the risk of nonpregnancy caused by high levels of MU was lower than reported in previous studies.
Wine tourism: Chilean wine regions and routes Hojman, David E.; Hunter-Jones, Philippa
Journal of business research,
2012, 2012-1-00, 20120101, Letnik:
65, Številka:
1
Journal Article
Recenzirano
Wine tourism is an important activity in several wine-producing countries. Yet the roles wine tourism plays within winery strategies remain unclear. This exploratory study investigates and ...differentiates the roles wine tourism plays within winery strategies in Chile. A generic literature review suggests that many questions remain unanswered within the wine tourism debate, substantial differences exist from country to country, and little of what researchers have uncovered seems to apply to Chile. The paper uses empirical data to systematically examine the various wine regions and routes in Chile, highlighting heterogeneities in demand and supply. One can classify winery business models into two broad strategies. The first is wineries that see wine tourism as a link in a long-distance, possibly inter-continental relationship marketing (RM) chain. The second is wineries that see wine tourism as their best hope of survival. The paper considers the implications of each strategy, both to Chile and to other wine-producing countries.
► Wine exports and wine tourism are very different propositions. ► Successful wine exports do not guarantee success in wine tourism. ► In Chile, wine tourism makes sense only as long-distance relationship marketing. ► If I pay US$100 for a bottle, I expect good facilities when I visit the winery. ► If wine production and exports are failing, wine tourism is not the answer.
Systematic off-line fluorination studies on all the stable lanthanide isotopes have been performed. The results are presented as a function of various parameters such as the target temperature, the ...type of ion source used (hot plasma or surface ionization) and the quantity of CF4 introduced. The first on-line measurements allowed us to determine the optimal experimental conditions for producing radioactive lanthanide isotopes.
A new detection system for time-optimized heavy-ion angular distribution measurements has been designed and constructed. This device is composed by an ionization chamber with a segmented-grid anode ...and three position-sensitive silicon detectors. This particular arrangement allows identifying reaction products emitted within a 30° wide angular range with better than 1° angular resolution. As a demonstration of its capabilities, angular distributions of the elastic scattering cross-section and the production of alpha particles in the 7Li+27Al system, at an energy above the Coulomb barrier, are presented.
•We constructed a detection system for time-optimized heavy-ion angular distribution measurements.•We characterized this device and obtained an energy resolution of 3% and an angular resolution of 1°.•We measured elastic scattering cross-sections in 7Li+27Al finding good agreement with previous data.•The performed tests included the measurement of alpha particle production cross-sections in 7Li+27Al.
Core and periphery in networks Hojman, Daniel A.; Szeidl, Adam
Journal of economic theory,
03/2008, Letnik:
139, Številka:
1
Journal Article
Recenzirano
We study a model of network formation where the benefits from connections exhibit decreasing returns and decay with network distance. We show that the unique equilibrium network is a ...periphery-sponsored star, where one player, the center, maintains no links and earns a high payoff, while all other players maintain a single link to the center and earn lower payoffs. Both the star architecture and payoff inequality are preserved in an extension of the model where agents can make transfers and bargain over the formation of links, under the condition that the surplus of connections increases in the size of agents’ neighborhoods. Our model thus generates two common features of social and economic networks: (1) a core-periphery structure; (2) positive correlation between network centrality and payoffs.
Use of milk urea (MU) concentration as a parameter for detection of nutritional imbalances requires identification and quantification of nutritional and nonnutritional factors that influence it. The ...objective of this study was to assess the relationship between live body weight (BW) and MU concentration in Holstein cows. Results for the test-day measurements at 7 dairy farms were obtained from the Israeli Dairy Herd Improvement Center and concomitant cow weights were registered in local computerized weighing systems. A total of 1996 cows and 25,485 records were studied. The overall unadjusted per-cow mean MU nitrogen concentration and BW were 15.3mg/dL (SD=3.8) and 593kg (SD=84), respectively. The linear association between BW and MU was negative and highly significant and the quadratic component of BW had a highly significant positive association with MU. There was a significant interaction between the association of MU and BW with lactation number. Sampling month, milk yield, milk fat percentage, and somatic cell count accounted for significant variation in MU. Predicted MU concentrations at different BW values were calculated for each parity group, by setting equations that included the estimates of the variables associated with MU and constant values (lactation averages) for the independent variables, with the exception of BW. Plotting of results showed exponential characteristics for the relationship between BW and predicted MU concentrations. At any of the considered BW, predicted MU concentrations were lower for first-parity cows. The trends and interactions found in the present study may contribute to improving accuracy of models designed to calculate urinary nitrogen excretion rates and normative milk urea concentrations.
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