This study was aimed to evaluate the degree of thermal stress exhibited by Holsteins under a continental temperate climate. Milk, fat, protein, and somatic cell count test-day records collected ...between 2000 and 2011 from 23,963 cows in 604 herds were combined with meteorological data from 14 public weather stations in Luxembourg. Daily values of 6 different thermal indices (TI) weighted in term of temperature, relative humidity, solar radiation, and wind speed were calculated by averaging hourly TI over 24h. Heat stress thresholds were first identified by a broken-line regression model. Regression models were thereafter applied to quantify milk production losses due to heat stress. The tipping points at which milk and protein yields declined were effectively identified. For fat yield, no valid threshold was identified for any of the studied TI. Daily fat yields tended to decrease steadily with increasing values of TI. Daily somatic cell score patterns were marked by increased values at both lowest and highest TI ranges, with a more pronounced reaction to cold stress for apparent temperature indices. Thresholds differed between TI and traits. For production traits, they ranged from 62 (TI1) to 80 (TI3) for temperature-humidity indices (THI) and from 16 (TI5) to 20 (TI6) for apparent temperature indices. Corresponding somatic cell score thresholds were higher and ranged from 66 (TI1) to 82 (TI3) and from 20 (TI5) to 23 (TI6), respectively. The largest milk decline per unit of mild, moderate, and extreme heat stress levels of 0.164, 0.356, and 0.955kg, respectively, was observed when using the conventional THI (TI1). The highest yearly milk, fat, and protein losses of 54, 5.7, and 4.2kg, respectively, were detected by TI2, the THI index that is adjusted for wind speed and solar radiation. The latter index could be considered as the best indicator of heat stress to be used for forecast and herd management in a first step in temperate regions under anticipated climate changes.
Genetic parameters that considered tolerance for heat stress were estimated for production, udder health, and milk composition traits. Data included 202,733 test-day records for milk, fat, and ...protein yields, fat and protein percentages, somatic cell score (SCS), 10 individual milk fatty acids (FA) predicted by mid-infrared spectrometry, and 7 FA groups. Data were from 34,468 first-lactation Holstein cows in 862 herds in the Walloon region of Belgium and were collected between 2007 and 2010. Test-day records were merged with daily temperature-humidity index (THI) values based on meteorological records from public weather stations. The maximum distance between each farm and its corresponding weather station was 21km. Linear reaction norm models were used to estimate the intercept and slope responses of 23 traits to increasing THI values. Most yield and FA traits had phenotypic and genetic declines as THI increased, whereas SCS, C18:0, C18:1 cis-9, and 4 FA groups (unsaturated FA, monounsaturated FA, polyunsaturated FA, and long-chain FA) increased with THI. Moreover, the latter traits had the largest slope-to-intercept genetic variance ratios, which indicate that they are more affected by heat stress at high THI levels. Estimates of genetic correlations within trait between cold and hot environments were generally high (>0.80). However, lower estimates (<=0.67) were found for SCS, fat yield, and C18:1 cis-9, indicating that animals with the highest genetic merit for those traits in cold environments do not necessarily have the highest genetic merit for the same traits in hot environments. Among all traits, C18:1 cis-9 was the most sensitive to heat stress. As this trait is known to reflect body reserve mobilization, using its variations under hot conditions could be a very affordable milk biomarker of heat stress for dairy cattle expressing the equilibrium between intake and mobilization under warm conditions.
The aim of this study was the evaluation of climate sensitivity via genomic reaction norm models i.e., to infer cow milk production and milk fatty acid (FA) responses on temperature-humidity index ...(THI) alterations. Test-day milk traits were recorded between 2010 and 2016 from 5,257 first-lactation genotyped Holstein dairy cows. The cows were kept in 16 large-scale cooperator herds, being daughters of 344 genotyped sires. The longitudinal data consisted of 47,789 test-day records for the production traits milk yield (MY), fat yield (FY), and protein yield (PY), and of 20,742 test-day records for 6 FA including C16:0, C18:0, saturated fatty acids (SFA), unsaturated fatty acids (UFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA). After quality control of the genotypic data, 41,057 SNP markers remained for genomic analyses. Meteorological data from the weather station in closest herd distance were used for the calculation of maximum hourly daily THI. Genomic reaction norm models were applied to estimate genetic parameters in a single-step approach for production traits and FA in dependency of THI at different lactation stages, and to evaluate the model stability. In a first evaluation strategy (New_sire), all phenotypic records from daughters of genotyped sires born after 2010 were masked, to mimic a validation population. In the second strategy (New_env), only daughter records of the new sires recorded in the most extreme THI classes were masked, aiming at predicting sire genomic estimated breeding values (GEBV) under heat stress conditions. Model stability was the correlation between GEBV of the new sires in the reduced data set with respective GEBV estimated from all phenotypic data. Among all test-day production traits, PY responded as the most sensitive to heat stress. As observed for the remaining production traits, genetic variances were quite stable across THI, but genetic correlations between PY from temperate climates with PY from extreme THI classes dropped to 0.68. Genetic variances in dependency of THI were very similar for C16:0 and SFA, indicating marginal climatic sensitivity. In the early lactation stage, genetic variances for C18:0, MUFA, PUFA, and UFA were significantly larger in the extreme THI classes compared with the estimates under thermoneutral conditions. For C18:0 and MUFA, PUFA, and UFA in the middle THI classes, genetic correlations in same traits from the early and the later lactation stages were lower than 0.50, indicating strong days in milk influence. Interestingly, within lactation stages, genetic correlations for C18:0 and UFA recorded at low and high THI were quite large, indicating similar genetic mechanisms under stress conditions. The model stability was improved when applying the New_env instead of New_sire strategy, especially for FA in the first stage of lactation. Results indicate moderately accurate genomic predictions for milk traits in extreme THI classes when considering phenotypic data from a broad range of remaining THI. Phenotypically, thermal stress conditions contributed to an increase of UFA, suggesting value as a heat stress biomarker. Furthermore, the quite large genetic variances for UFA at high THI suggest the consideration of UFA in selection strategies for improved heat stress resistance.
Renewed interest in heat stress effects on livestock productivity derives from climate change, which is expected to increase temperatures and the frequency of extreme weather events. This study aimed ...at evaluating the effect of temperature and humidity on milk production in highly selected dairy cattle populations across 3 European regions differing in climate and production systems to detect differences and similarities that can be used to optimize heat stress (HS) effect modeling. Milk, fat, and protein test day data from official milk recording for 1999 to 2010 in 4 Holstein populations located in the Walloon Region of Belgium (BEL), Luxembourg (LUX), Slovenia (SLO), and southern Spain (SPA) were merged with temperature and humidity data provided by the state meteorological agencies. After merging, the number of test day records/cows per trait ranged from 686,726/49,655 in SLO to 1,982,047/136,746 in BEL. Values for the daily average and maximum temperature-humidity index (THIavg and THImax) ranges for THIavg/THImax were largest in SLO (22–74/28–84) and shortest in SPA (39–76/46–83). Change point techniques were used to determine comfort thresholds, which differed across traits and climatic regions. Milk yield showed an inverted U-shaped pattern of response across the THI scale with a HS threshold around 73 THImax units. For fat and protein, thresholds were lower than for milk yield and were shifted around 6 THI units toward larger values in SPA compared with the other countries. Fat showed lower HS thresholds than protein traits in all countries. The traditional broken line model was compared with quadratic and cubic fits of the pattern of response in production to increasing heat loads. A cubic polynomial model allowing for individual variation in patterns of response and THIavg as heat load measure showed the best statistical features. Higher/lower producing animals showed less/more persistent production (quantity and quality) across the THI scale. The estimated correlations between comfort and THIavg values of 70 (which represents the upper end of the THIavg scale in BEL-LUX) were lower for BEL-LUX (0.70–0.80) than for SPA (0.83–0.85). Overall, animals producing in the more temperate climates and semi-extensive grazing systems of BEL and LUX showed HS at lower heat loads and more re-ranking across the THI scale than animals producing in the warmer climate and intensive indoor system of SPA.
This work deals with the dielectric properties of silane treated pineapple leaf fiber and kenaf fiber reinforced phenolic hybrid composites. The aim of the present paper is to investigate the effect ...of silane treatment on the pineapple leaf fiber–kenaf fiber/matrix interfacial adhesion using the dielectric relaxation spectroscopy in the frequency range from 0.1 Hz to 1 MHz and temperature range from 50 to 180℃. Our hybrid composites were fabricated by hand lay-up method at 50% total fiber loading. All the results obtained were discussed in terms of dynamic molecular and interfacial process. Two interfacial polarizations identified as the Maxwell–Wagner–Sillars effect are observed. We note that silane treatment improved the interfacial adhesion between pineapple leaf fiber/kenaf fiber and phenolic resin and it will help to develop high performance kenaf fiber/pineapple leaf fiber reinforced polymer composites for industrial applications. In fact, as known, the silane treatment developed hydrophobic nature in pineapple leaf fiber and kenaf fiber which is very positive for fiber/matrix compatibility.
In this work, the dielectric properties and the electrical conductivity of polyvinyl acetate (PVAc) polymer doped with cellulose nanocrystals (CNC), extracted from the date palm rachis, are reported. ...We investigate the filler effect on the molecular mobility of the PVAc polymer chains and the charge transport properties of this material. PVAc/CNC films structure was characterized by powder X-Ray diffraction (XRD), showing the crystalline behavior of the cellulose filler. The dielectric properties were investigated using impedance spectroscopy, in the frequency range of 102–106 Hz and temperatures from 200 to 350 K. A β relaxation, assigned to the motions of the -OCOCH3 side groups, and α relaxation, associated with the glass transition of the PVAc matrix, can be detected.
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•Polyvinyl-acetate/cellulose nanocrystals nanocomposites are investigated.•The fragility parameters and activated energy for different process are evaluated.•Electrical conductivity are investigated using DC measurements .•High activation energy values prove that the conductivity is of an ionic nature.
Alexandrite laser is more adapted for lighter hair but not for darker skin, while the Nd:YAG laser is more suitable for darker skin but not for lighter hair.BACKGROUNDAlexandrite laser is more ...adapted for lighter hair but not for darker skin, while the Nd:YAG laser is more suitable for darker skin but not for lighter hair.To evaluate both laser used as single treatment and in simultaneous emission for axillary hair removal.OBJECTIVETo evaluate both laser used as single treatment and in simultaneous emission for axillary hair removal.Ten patients (18-40 years old) were selected for this study. The spot size and pulse time were kept constant for all patients, 14 mm and 5 ms, respectively. The fluences were 20 to 28 J/cm2, 16 to 25 J/cm2, and 14-8 J/cm2 to 25-13 J/cm2 for Nd:YAG, alexandrite and the combined alex/YAG, respectively. Three treatment sessions were performed at 6-week interval, and patients were reviewed 4 months after the last session.METHODTen patients (18-40 years old) were selected for this study. The spot size and pulse time were kept constant for all patients, 14 mm and 5 ms, respectively. The fluences were 20 to 28 J/cm2, 16 to 25 J/cm2, and 14-8 J/cm2 to 25-13 J/cm2 for Nd:YAG, alexandrite and the combined alex/YAG, respectively. Three treatment sessions were performed at 6-week interval, and patients were reviewed 4 months after the last session.The median number of hairs reduced from 46.00 to 33.00 (p = .022) for alexandrite, from 44.50 to 30.00 (p = .02) for Nd:YAG and from 56.00 to 19.50 (p = .005) for alexandrite-Nd:YAG, equivalent to 46.70%, 27.74% and 70.12% median hair reduction, respectively.RESULTSThe median number of hairs reduced from 46.00 to 33.00 (p = .022) for alexandrite, from 44.50 to 30.00 (p = .02) for Nd:YAG and from 56.00 to 19.50 (p = .005) for alexandrite-Nd:YAG, equivalent to 46.70%, 27.74% and 70.12% median hair reduction, respectively.The simultaneous emission of both 755 nm and 1064 nm Nd:YAG laser is significantly more effective than a single laser treatment. Future studies are needed to confirm the good results of this innovative technique.CONCLUSIONSThe simultaneous emission of both 755 nm and 1064 nm Nd:YAG laser is significantly more effective than a single laser treatment. Future studies are needed to confirm the good results of this innovative technique.
Attributing to the chemical sensor application based on charge transfer phenomena between the host and the guest for new derivative of calix 4quinone, 1,3-alternate-calix 4quinone (C4Q), have been ...investigated via DFT-D3 calculation and compared to the experimental data. The structural design of the title molecule has been characterized, and the organic quinone has been clearly identified. The selected sites for the Cu2+, Ag2+ and Hg2+ cations by the calix 4quinone molecule have been discussed. The molecular electrostatic potential (MEP) map has been performed in order to identify the highly attractive site for the selected cations. The 1H NMR chemical shifts of the stable complexes have been calculated. Moreover, the calculated stretching vibrational modes in the most stable conformations have been assigned and compared with the experimental ones. The UV–Vis spectroscopy revealed that the interaction of the Cu2+, Ag2+ (d9 electron configuration) and Hg2+(d10 electron configuration) cations with the C4Q is reinforced with the red shifting to high absorption bands of the free molecule. The HOMO and LUMO orbital iso-surfaces exhibit that the C4Q-Cu2+ complex has the highest charge transfer terms (CTT) which increased the overall energetic stabilization of the system. The Hirshfeld surface (HS) showed the highly attractive energetic binds that favor the efficient charge transfer phenomena between the two systems. The interactions between the host (C4Q) and guest (metal cation) are discussed deeply using the topological AIM and non-covalent RDG index analyses. The computed values from electron density and the binding energies for all active bonds have been interpreted. Finally, the ELF/LOL at bond critical points and ELF maps are computed to confirm and visualize the donor-acceptor couple formed between the selected host-guest systems.
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•Higher metal cations adsorption with C4Q through the electron released exchange process.•Electronic properties identified the charge transfer phenomena between the host and the guest.•The Hirshfeld surface (HS) is used to determine the high attractive energetic binds.•The host-guest interactions are discussed through AIM-RDG and ELF analyses.•C4Q is suitable to have a good performance sensor.
The challenge of managing and breeding dairy cows is permanently adapting to changing production circumstances under socio-economic constraints. If managing and breeding address different timeframes ...of action, both need relevant phenotypes that allow for precise monitoring of the status of the cows, and their health, behavior, and well-being as well as their environmental impact and the quality of their products (i.e., milk and subsequently dairy products). Milk composition has been identified as an important source of information because it could reflect, at least partially, all these elements. Major conventional milk components such as fat, protein, urea, and lactose contents are routinely predicted by mid-infrared (MIR) spectrometry and have been widely used for these purposes. But, milk composition is much more complex and other nonconventional milk components, potentially predicted by MIR, might be informative. Such new milk-based phenotypes should be considered given that they are cheap, rapidly obtained, usable on a large scale, robust, and reliable. In a first approach, new phenotypes can be predicted from MIR spectra using techniques based on classical prediction equations. This method was used successfully for many novel traits (e.g., fatty acids, lactoferrin, minerals, milk technological properties, citrate) that can be then useful for management and breeding purposes. An innovation was to consider the longitudinal nature of the relationship between the trait of interest and the MIR spectra (e.g., to predict methane from MIR). By avoiding intermediate steps, prediction errors can be minimized when traits of interest (e.g., methane, energy balance, ketosis) are predicted directly from MIR spectra. In a second approach, research is ongoing to detect and exploit patterns in an innovative manner, by comparing observed with expected MIR spectra directly (e.g., pregnancy). All of these traits can then be used to define best practices, adjust feeding and health management, improve animal welfare, improve milk quality, and mitigate environmental impact. Under the condition that MIR data are available on a large scale, phenotypes for these traits will allow genetic and genomic evaluations. Introduction of novel traits into the breeding objectives will need additional research to clarify socio-economic weights and genetic correlations with other traits of interest.
A survey of relaxation processes in glasses exhibiting ionic and electronic–ionic conductivity mechanisms is presented. Electrical conductivity and dielectric properties are investigated using ...complex impedance spectroscopy in a frequency range from 0.1 to 10
6
Hz and a temperature range from 253 to 423 K. The results reveal that ionic conduction depends on the alkali concentration and ion mobility while electrical conduction is only slightly influenced by alkali ions and a mixed electronic–ionic conduction can occur. The Jonscher’s expression of ac electric conductivity is modified by adding a new term taking into account the displacement current density associated with the dielectric relaxation. The change in the activation energy depends upon the chemical composition indicating a changeover of the predominant conduction mechanism from ionic to polaronic. Quantum mechanical tunneling (QMT) model was suggested to describe the conduction mechanism of alkali-silicate glass G1 where frequency exponent s < 1. However, small polaron tunneling (SPT) model was applied to describe conductivity of semiconductor glass G2 (alkali-silicate glass with iron ions) with s > 1, whose conduction mechanism may be considered in terms of the optical phonon assisted hopping of small polarons between overlapping states. The electrical modulus exhibited relaxation character.
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