Objective: The aim of this study was to investigate the effects of dietary supplementation with a multi-strain probiotic (MSP) product containing of Bifidobacterium animalis, Lactobacillus casei, Streptococcus faecalis, and Bacillus cerevisiae on growth, health, and fecal bacterial composition of dairy calves during the first month of life.Methods: Forty Holstein calves (24 female and 16 male) at 2 d of age were grouped by sex and date of birth then randomly assigned to 1 of 4 treatments: milk replacer supplementation with 0 g (0MSP), 2 g (2MSP), 4 g (4MSP), and 6 g (6MSP) MSP per calf per day.Results: Supplementation of MSP did not result in any significant differences in parameters of body measurements of calves during the 30 d period. As the dosage of MSP increased, the average daily gain (p = 0.025) and total dry matter intake (p = 0.020) of calves showed a linear increase. The fecal consistency index of the 2MSP, 4MSP, and 6MSP group calves were lower than that of the 0MSP group calves (p = 0.003). As the dosage of MSP increased, the concentrations of lactate dehydrogenase (p = 0.068) and aspartate aminotransferase (p = 0.081) in serum tended to decrease, whereas the concentration of total cholesterol increased quadratically (p = 0.021). The relative abundance of Dorea in feces was lower (p = 0.011) in the 2MSP, 4MSP, and 6MSP group calves than that in the 0MSP group calves. The relative abundance of Dorea (p = 0.001), Faecalibacterium (p = 0.050), and Mitsuokella (p = 0.030) decreased linearly, whereas the relative abundance of Prevotella tended to increase linearly as the dosage of MSP increased (p = 0.058).Conclusion: The MSP product can be used to reduce the diarrhea, improve the performance, and alter the composition of the fecal bacteria in neonatal dairy calves under the commercial conditions.
11 December 2015 in Journal of the Atmospheric Sciences
Based on the hydrostatic, incompressible Boussinesq equations in the planetary boundary layer (PBL), the three-dimensional sea–land breeze (SLB) circulation has been elegantly expressed as functions of the surface temperature distribution. The horizontal distribution of the horizontal or vertical motion is determined by the first or second derivative of the surface temperature distribution. For symmetric land–sea and temperature distribution, the full strength of the sea breeze occurs inland but not at the coastline, and the maximum updraft associates with the heating center. Setting the temperature difference between land and sea (TDLS), which varies with the island size, there would exist an optimal island size corresponding to the strongest SLB circulation that weakens with both a larger and smaller island size. Each velocity component approaches a peak at a certain vertical level. Both the peak value and the corresponding vertical level link with the vertical scale of the surface temperature: the more significant the influence of the surface temperature vertically, the stronger the SLB circulation at a higher vertical level it induces. The Weather Research and Forecasting (WRF) Model's ideal simulation for the two-dimensional sea breeze is applied to verify the theory. Two cases, land breeze and sea breeze, further support the theory's results despite a certain slight discrepancy due to the highly simplified theoretical equations.
6 January 2022 in Advances in Atmospheric Sciences
This paper investigates the impact of equatorial wind stress on the equatorial Ekman transport during the Indian Ocean Dipole (IOD) mature phase. The results show that the equatorial zonal wind stress directly drives the meridional motion of seawater at the upper levels. In normal years, the zonal wind stress south of the equator is easterly and that north of the equator is westerly, which contributes to southward Ekman transport at the upper levels to form the climatological Indian Ocean shallow meridional overturning circulation. During the years of positive IOD events, abnormal easterly winds near the equator bring southward Ekman transport south of the equator while they bring northward Ekman transport north of the equator. This causes the seawater to move away from the equator and hence induces upwelling near the equator, which forms a pair of small circulation cells that are symmetric about the equator at the upper levels (approximately 100 m deep). The abnormal circulation cell south (north) of the equator strengthens (weakens) the southward (southward) motion south (north) of the equator. During years with negative IOD events, the opposite occurs. In addition, during the mature period of IOD, the remote sea surface temperature anomaly (SSTA) such as El Niño–Southern Oscillation (ENSO) may exert some influence on Ekman transport anomaly near the equator during the mature period of IOD.
The characteristics of urban heat island (UHI) circulation are analytically expressed as functions of the surface temperature in both temperature inversion and non-temperature inversion (NTI) profiles, in which the temperature declines with increasing altitudes. To identify how the inversion layer affects UHI circulation, two temperature profiles are specified to be nearly similar except within the temperature inversion layer. Theoretical calculations suggest that the UHI circulation in the temperature inversion case is weaker and lower than in the NTI case and that there is no significant difference between the two cases. When the inversion layer thickness is fixed, the relative size difference between the weakening inversion intensity and the strengthening temperature influence above the inversion lid controls the decrease or increase in UHI circulation.