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1.
Gender of the calf whose birth initiates lactation could influence whole lactation milk yield of the dam due to hormonal influences on mammary gland development, or through calf gender effects on gestation length. Fetal gender could influence late lactation yields because cows become pregnant at peak lactation. The effects of calf gender sequences in parities 1–3 were assessed by separately fitting animal models to datasets from New Zealand comprising 274 000 Holstein Friesian and 85 000 Jersey cows, decreasing to 12 000 and 4 000 cows by parity 3. The lactation initiated by the birth of a female rather than a male calf was associated with a 0.33–1.1% (p≤0.05) higher milk yield. Female calf gender had carryover effects associated with higher milk yield in second lactations for Holstein Friesians (0.24%; p = 0.01) and third lactations for Jerseys (1.1%; p = 0.01). Cows giving birth to bull calves have 2 day longer gestations, which reduces lactation length in seasonal calving herds. Adding a covariate for lactation length to the animal model eroded some of these calf gender effects, such that calving a female led to higher milk yield only for second lactation Holstein Friesians (1.6%; p = 0.002). The interval centering method generates lower estimates of whole lactation yield when Wood’s lactation curves are shifted to the right by 2 days for male calves and this explained the higher yield in female calves when differences in lactation length were considered. Correlations of estimated breeding values between models including or excluding calf gender sequence were 1.00 for bulls or cows. Calf gender primarily influences milk yield through increased gestation length of male calves, and bias associated with the interval centering method used to estimate whole lactation milk yields. Including information on calf gender is unlikely to have an effect on selection response in New Zealand dairy cattle. 相似文献
2.
Walter S. Svagelj María Magdalena Trivellini Flavio Quintana 《Ethology : formerly Zeitschrift fur Tierpsychologie》2012,118(3):251-259
Nest defence is a common form of parental care employed by birds to improve the survival of their offspring. Theory predicts that parents should adjust their nest defence according to the value of the brood at stake, defending more intensively broods with high survival and reproductive prospects. We evaluated the influence of offspring number, offspring age, laying date and parent sex on nest‐defence intensity (NDI) of the Imperial Shag Phalacrocorax atriceps, a sexually dimorphic seabird with seasonal decline in offspring survival and very limited renesting potential. We also evaluated whether NDI was correlated within pairs and whether NDI of both members of the pair was correlated with incubation and breeding success. To elicit defensive behaviour, we simulated predation attempts using a Kelp Gull Larus dominicanus model. As predicted by theory, NDI was positively correlated with the number of offspring in the nest and offspring age. NDI during chick rearing was higher than that at early and late incubation, while no differences were found between incubation stages. Contrary to our prediction, we did not find differences in NDI according to laying date. NDI for males was higher than females, while NDI was also positively correlated within pairs. NDI was not statistically related to incubation or breeding success. These results suggest that other factors, such as laying date or parental quality and age, play a much larger role in determining the outcome and productivity of a nesting attempt. Our results provide partial support for parental investment theory; while parental defence increased with brood value according to offspring number and age, parental defence was not related to laying date, a factor strongly affecting offspring survival and recruitment probabilities in this species. 相似文献
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4.
Xiao Zijun Shen Jie Li Yang Wang Zhuo Zhao Yanshuang Chen Yong Zhao Jing-yi 《Probiotics and antimicrobial proteins》2022,14(5):792-803
Probiotics and Antimicrobial Proteins - Nattokinase (NK) is a potent fibrinolytic enzyme with wide pharmaceutical and nutraceutical applications. Safe and high NK-yielding strains are urgently... 相似文献
5.
《Bioscience, biotechnology, and biochemistry》2013,77(5):750-752
A process was developed to produce a characteristic milk gel. Raw and market milk samples were freeze-concentrated using bacterial ice nuclei. The concentrates were kept at 5°C and compressed at 300–600 MPa for 5 min. The combination of the freeze concentration and the pressurization gave a milk gel without adding any gelling agents. The addition of sugar at 10% to the concentrated milk improved its gel strength and viscoelasticity. The gel was characterized by a phase transition at about 62–75°C. 相似文献
6.
Anita L. Michel Claire Geoghegan Tiny Hlokwe Keneilwe Raseleka Wayne M. Getz Tanguy Marcotty 《PloS one》2015,10(6)
Background
Unpasteurised fresh and souring dairy products form an essential component of household diets throughout many rural communities in southern Africa. The presence of milk-borne zoonotic pathogens such as Mycobacterium bovis (M. bovis), the causative agent of bovine tuberculosis and zoonotic tuberculosis in humans, constitute a public health threat, especially in remote areas with poor disease surveillance in livestock and highly compromised human health due to HIV/AIDS.Methods
In this study we used culture to determine the longevity of M. bovis in experimentally inoculated fresh and naturally souring milk obtained from communal cattle in the KwaZulu-Natal province of South Africa. The effect of bacterial load and storage temperature on the survival of M. bovis was evaluated by spiking mixtures of fresh milk and starter soured milk (aMasi) culture with three concentrations of bacteria (102, 104, 107 colony forming units/ml), followed by incubation under controlled laboratory conditions that mimicked ambient indoor (20°C) and outdoor (33°C) temperatures and periodic sampling and testing over time (0-56 days).Results
M. bovis cultured from samples of the fresh and souring milk was identified by PCR analysis. At the highest spiking concentration (107cfu/ml), M. bovis survived for at least 2 weeks at 20°C; but, at all concentrations in the 33°C treatment, M. bovis was absent by three days after inoculation. Logistic regression analysis was used to assess the effects of bacterial concentration and time since inoculation, as well as determine the potential half-life of M. bovis in raw souring milk. Given the most favourable tested conditions for bacterial survival (20°C), approximately 25% of mycobacteria were alive after one day of storage (95% CI: 9-53%), giving an estimated half-life of M. bovis in raw souring milk of approximately 12 hours (95% CI: 7-27 hours).Conclusions
This study demonstrates that M. bovis may survive in fresh and souring milk for periods of time that represent a risk of exposure to people consuming these products, as well as domestic or wild animal populations that have reported opportunities to consume homemade unpasteurised dairy products. The temperature at which the milk is soured and stored substantially affects the survival time of M. bovis. 相似文献7.
Alicia Barbero Susana Astiz Clemente J. Lopez-Bote Maria L. Perez-Solana Miriam Ayuso Isabel Garcia-Real Antonio Gonzalez-Bulnes 《PloS one》2013,8(10)
The present study aimed to determine, in a swine model of leptin resistance, the effects of type and timing of maternal malnutrition on growth patterns, adiposity and metabolic features of the progeny when exposed to an obesogenic diet during their juvenile development and possible concomitant effects of the offspring sex. Thus, four groups were considered. A CONTROL group involved pigs born from sows fed with a diet fulfilling their daily maintenance requirements for pregnancy. The treated groups involved the progeny of females fed with the same diet but fulfilling either 160% or 50% of pregnancy requirements during the entire gestation (OVERFED and UNDERFED, respectively) or 100% of requirements until Day 35 of pregnancy and 50% of such amount from Day 36 onwards (LATE-UNDERFED). OVERFED and UNDERFED offspring were more prone to higher corpulence and fat deposition from early postnatal stages, during breast-feeding; adiposity increased significantly when exposed to obesogenic diets, especially in females. The effects of sex were even more remarkable in LATE-UNDERFED offspring, which had similar corpulence to CONTROL piglets; however, females showed a clear predisposition to obesity. Furthermore, the three groups of pigs with maternal malnutrition showed evidences of metabolic syndrome and, in the case of individuals born from OVERFED sows, even of insulin resistance and the prodrome of type-2 diabetes. These findings support the main role of early nutritional programming in the current rise of obesity and associated diseases in ethnics with leptin resistance. 相似文献
8.
Ellis L 《Social biology》2004,51(3-4):144-160
This article offers a theoretical explanation for relationships between social status and involvement in serious and persistent criminal behavior from an evolutionary perspective. The theory's central premise is that natural selection has produced females who bias their mating choices toward males who strive for status. This bias has resulted in males devoting greater time and energy to status striving (relative to females). To account for why nearly all "victimizing" forms of criminality are more common among males than among females, the theory asserts that status striving exists along a continuum of competitive/victimizing behavior. One end of this continuum is epitomized by crude (criminal) forms of the behavior that societies generally discourage and even punish. The other end consists of sophisticated (commercial) forms that societies tolerate and even encourage. According to the theory, most males begin to exhibit non-playful forms of competitive/victimizing behavior around the onset of puberty as they start their reproductive careers. Adolescent males with the greatest abilities to learn will transition quickly from crude forms of competitive/victimizing behavior to more sophisticated forms, while males who have the greatest difficulties learning will transition more slowly. A major deduction from the theory is that genes on the Y-chromosome must be affecting the brain in ways that promote status-striving behavior. This deduction needs empirical scrutiny, although it is consistent with evidence (a) that the Y-chromosome transforms would-be ovaries into testes, the latter being specialized organs for the production of testosterone, and (b) that testosterone alters brain functioning in ways that contribute to both status striving and criminality. 相似文献
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Gregory D. Webster Angela Bryan Charles B. Crawford Lisa McCarthy Brandy H. Cohen 《Human nature (Hawthorne, N.Y.)》2008,19(2):189-210
Supporting Hamilton’s inclusive fitness theory, archival analyses of inheritance patterns in wills have revealed that people invest more of their estates in kin of closer genetic relatedness. Recent classroom experiments have shown that this genetic relatedness effect is stronger for relatives of direct lineage (children, grandchildren) than for relatives of collateral lineage (siblings, nieces, nephews). In the present research, multilevel modeling of more than 1,000 British Columbian wills revealed a positive effect of genetic relatedness on proportions of estates allocated to relatives. This effect was qualified by an interaction with lineage, such that it was stronger for direct than for collateral relatives. Exploratory analyses of the moderating role of benefactors’ sex and estate values showed the genetic relatedness effect was stronger among female and wealthier benefactors. The importance of these moderators to understanding kin investment in modern humans is discussed. 相似文献
11.
Dietrich Uhlmann 《International Review of Hydrobiology》1978,63(3):353-363
In laboratory models of sewage ponds operated on a semicontinuous-flow basis, the net primary production II of the phytoplankton was measured by harvesting the suspended matter both from the outflow and the bottom of the vessels at daily intervals. The maximum value of II was as high as 50 mg dry weight/l day (corresponding to 20 mg C/l day). With the nutrient load L kept ad a constant level, the steady state phytoplankton biomass x decreased with decreasing water residence time t in accordance with the dropping inflow concentration of the nutrients. On the other hand, at 20 °C no higher x was yielded at t =40 than at t =5 days. This result obviously has to be attributed to a substantial increase in grazing rate with progressing t at the temperature level of 20 and 30 °C. In this connection extremely low magnitudes of II may result despite optimum levels of nutrient supply, radiation and temperature. The highest estimates of II hitherto measured and recorded in the literature relate to the euphotic zone depth (zeu in m) as follows: 相似文献
12.
Page J de la Fuente R Gómez R Calvente A Viera A Parra MT Santos JL Berríos S Fernández-Donoso R Suja JA Rufas JS 《Chromosoma》2006,115(3):250-259
During first meiotic prophase, homologous chromosomes are held together by the synaptonemal complex, a tripartite proteinaceous structure that extends along the entire length of meiotic bivalents. While this feature is applicable for autosomes, sex chromosomes often escape from this rule. Many species present sex chromosomes that differ between them in their morphology, length, and gene content. Moreover, in some species, sex chromosomes appear in a single dose in one of the sexes. In all of these cases, the behavior of sex chromosomes during meiosis is conspicuously affected, and this includes the assembly and dynamics of the synaptonemal complex. We review in this study the structure of the synaptonemal complex in the sex chromosomes of three groups of organisms, namely: mammals, orthopterans, and hemipterans, which present different patterns of sex chromosome structure and behavior. Of special interest is the analysis of the organization of the axial/lateral elements of the synaptonemal complex in relation to other axial structures organized along meiotic chromosomes, mainly the cohesin axis. The differences found in the behavior of both axial structures reveal that while the organization of a cohesin axis along sex chromosomes is a conserved feature in most organisms and it shows very little morphological variations, the axial/lateral elements of the synaptonemal complex present a wide range of structural modifications on these chromosomes.Electronic Supplementary Material Supplementary material is available for this article at
The synaptonemal complex—50 years 相似文献
13.
Leidy Ricaurte Rosa Erlide Prieto Correa María de Jesus Perea-Flores María Ximena Quintanilla-Carvajal 《Food biophysics》2017,12(4):439-450
The milk whey is a by-product of the dairy industry with a relevant protein concentration which can be employed as a wall material in spray drying processes. In this work, milk whey was used to encapsulate high oleic palm oil (HOPO) nanoemulsions. The HOPO/whey ratio and the atomization system (two-fluid nozzle and rotary disc) had a significant influence in the capsule formation. In addition, the release of the oleic acid (AO) from HOPO was evaluated by dialysis bag method for powders obtained by both types of atomizers. Different powders were obtained with good physical properties (particle diameter: 6.1–18.8 μm, aw: 0.058–0.125, moisture: 0.86–2.39%, bulk density: 390–770 kg/m3, dissolution rate: 55–115s) from stable nanoemulsions with high encapsulation efficiencies (77 to 99%). On the other hand, the release percents of AO were 82.8 and 75.8% for the two-fluid nozzle and the rotary disc, respectively. The release was not completed in the tested time (7 h) due to stable HOPO-whey linkages, and the gradient that must be broken was higher. Aditionally, an inverse relation was found between diameter particle and AO release. 相似文献
14.
Anders Linde-Laursen 《American anthropologist》1997,99(4):849-850
Communities of Faith: Sectarianism, Identity, and Social Change on. Danish Island. Andrew Buckser. New Directions in Anthropology, 5. Providence, RI, and Oxford, England: Berghahn Books, 1996. 264 pp. 相似文献
15.
Solveig Myking Heather A. Boyd Ronny Myhre Bjarke Feenstra Astanand Jugessur Aase S. Devold Pay Ingrid H. G. ?stensen Nils-Halvdan Morken Tamara Busch Kelli K. Ryckman Frank Geller Per Magnus H?kon K. Gjessing Mads Melbye Bo Jacobsson Jeffrey C. Murray 《PloS one》2013,8(4)
Background
Recent epidemiological studies suggest that the maternal genome is an important contributor to spontaneous preterm delivery (PTD). There is also a significant excess of males among preterm born infants, which may imply an X-linked mode of inheritance for a subset of cases. To explore this, we examined the effect of maternal and fetal X-chromosomal single nucleotide polymorphisms (SNPs) on the risk of PTD in two independent genome-wide association studies and one replication study.Methods
Participants were recruited from the Danish National Birth Cohort and the Norwegian Mother and Child cohort studies. Data from these two populations were first analyzed independently, and then combined in a meta-analysis. Overall, we evaluated 12,211 SNPs in 1,535 case-mother dyads and 1,487 control-mother dyads. Analyses were done using a hybrid design that combines case-mother dyads and control-mother dyads, as implemented in the Haplin statistical software package. A sex-stratified analysis was performed for the fetal SNPs. In the replication study, 10 maternal and 16 fetal SNPs were analyzed using case-parent triads from independent studies of PTD in the United States, Argentina and Denmark.Results
In the meta-analysis, the G allele at the maternal SNP rs2747022 in the FERM domain containing 7 gene (FRMD7) increased the risk of spontaneous PTD by 1.2 (95% confidence interval (CI): 1.1, 1.4). Although an association with this SNP was confirmed in the replication study, it was no longer statistically significant after a Bonferroni correction for multiple testing.Conclusion
We did not find strong evidence in our data to implicate X-chromosomal SNPs in the etiology of spontaneous PTD. Although non-significant after correction for multiple testing, the mother’s G allele at rs2747022 in FRMD7 increased the risk of spontaneous PTD across all populations in this study, thus warranting further investigation in other populations. 相似文献16.
Toxin Production by Microcystis aeruginosa as a Function of Light in Continuous Cultures and Its Ecological Significance
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The effects of light intensity and light quality on toxin production by Microcystis aeruginosa were examined in continuous cultures. Light intensity had a pronounced effect on toxicity and the toxin production rate. Toxicity and the toxin production rate increased with light intensity up to an intensity of about 40 microeinsteins m-2 s-1 and decreased at higher light intensities, while the ratio of toxin to protein was constant at intensities of more than 40 microeinsteins m-2 s-1. Light quality had only slight effects on toxicity. The results of our laboratory experiments were supported by the results of field work in which we examined toxin production at different depths in a lake. Our observations explain the mixed pattern of high and low toxicity found in a surface bloom of M. aeruginosa. Our findings also indicate that production of the peptide toxin can be uncoupled from general protein synthesis. 相似文献
17.
《四川动物》2017,(2)
鸣声在鸣鸟的生活史中具有重要作用,是其与外界进行信息交流最有效的方式之一。鸟类的鸣唱与其个体因素(如体型、子代性别比等)有着十分重要的联系。为了揭示个体体型、子代性别比与鸣唱特征之间的相关性,于2014—2015年3—6月在辽宁省仙人洞国家级自然保护区对杂色山雀指名亚种Parus varius varius的鸣声进行录制,测量了各体型参数,并对每巢雏鸟进行性别鉴定。结果显示:(1)杂色山雀体型与其鸣唱的最高频率具有显著相关性,但单一体型参数(体质量、跗蹠长度)与其鸣声参数相关性均不显著;(2)鸣唱语句长度与子代性别比具有显著相关性,子代性别比与其他鸣声参数均不存在显著相关性。本研究结果有助于进一步了解小型鸟类体型与鸣唱的关系,以及鸣唱与子代性别比之间的关系。 相似文献
18.
OBJECTIVE--The almost twofold difference in lung cancer incidence between people living in Copenhagen and in rural area of Denmark in the 1980s led to public concern; this study was undertaken to assess the effects of air pollution and occupation on lung cancer in Denmark, with control for smoking habits. DESIGN--Cohort study of national population. SUBJECTS--People aged 30-64 and economically active in 1970 (927,470 men and 486,130 women). MAIN OUTCOME MEASURES--Relative risks for lung cancer estimated with multiplicative Poisson modelling of incidence rates. RESULTS--Differences in smoking habit explained about 60% of the excess lung cancer risk in Copenhagen for men and 90% for women. After control for smoking, workers had double the lung cancer risk of teachers and academics. There was only a small independent effect of region. CONCLUSION--Smoking is the main factor behind the regional differences in lung cancer incidence in Denmark, and occupational risk factors also seem to have an important role. The outdoor air in Copenhagen around 1970 contained on average 50-80 micrograms/m3 of sulphur dioxide, 80-100 micrograms/m3 total suspended particulate matter, and up to 10 ng/m3 benzo(a)pyrene and had peak values of daily smoke of 120 micrograms/m3. Region had only a small effect on incidence of lung cancer int eh present study, which suggests that an influence of outdoor air pollution on lung cancer is identifiable only above this pollution level. 相似文献
19.
Tittle CR 《Social biology》2004,51(3-4):166-70; discussion 171-3
20.
Fish manipulation as a lake restoration tool in shallow,eutrophic temperate lakes 1: cross-analysis of three Danish case-studies 总被引:9,自引:10,他引:9
Jeppesen E. Søndergaard M. Mortensen E. Kristensen P. Riemann B. Jensen H. J. Müller J. P. Sortkjær O. Jensen J. P. Christoffersen K. Bosselmann S. Dall E. 《Hydrobiologia》1990,200(1):205-218
The use of fish manipulation as a tool for lake restoration in eutrophic lakes has been investigated since 1986 in three shallow,
eutrophic Danish lakes. The lakes differ with respect to nutrient loading and nutrient levels (130–1000 μg P l−1, 1–6 mg N l−1). A 50% removal of planktivorous fish in the less eutrophic cyanobacteria-diatom dominated Lake V?ng caused marked changes
in lower trophic levels, phosphorus concentration and transparency. Only minor changes occurred after a 78% removal of planktivorous
fish in eutrophic cyanobacteria dominated Frederiksborg Castle Lake. In the hypertrophic, green algae dominated Lake S?byg?rd
a low recruitment of all fish species and a 16% removal of fish biomass created substantial changes in trophic structure,
but no decrease in phosphorus concentration. The different response pattern is interpreted as (1) a difference in density
and persistence of bloomforming cyanobacteria caused by between-lake variations in nutrient levels and probably also mixing-
and flushing rates, (2) a difference in specific loss rates through sedimentation of the algal community prevaling after the
fish manipulation, (3) a decreased impact of planktivorous fish with increasing mean depth and (4) a lake specific difference
in ability to create a self-increasing reduction in the phosphorus level in the lake water. This in turn seems related to
the phosphorus loading. 相似文献