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81.
A water and dye-free heat treatment method was used to color wool fibers. The heat effect changed wool fibers to different colors from white in a nitrogen atmosphere. The influences of heating temperature and time on the colors of wool were investigated and the mechanical property of colored wool fibers was evaluated. The color strength of wool fibers increased as heat treatment temperature and time increased. The tensile strength retention rate of wool fiber was relatively high (≥90 %) when the heat temperature was below 200 °C. The surface morphologies of wool fibers scarcely changed during the heat treatment. The carbon content of fibers was found to reduce by heat treatment, indicating oxidization of components in the wool fibers in the process of coloration. Heat treatment may provide a water and dye-free approach to color wool and other textile fibers, albeit within a limited color range. 相似文献
82.
Simulating the cumulative effects of multiple forest management strategies on landscape measures of forest sustainability 总被引:1,自引:2,他引:1
While the cumulative effects of the actions of multiple owners have long been recognized as critically relevant to efforts
to maintain sustainable forests at the landscape scale, few studies have addressed these effects. We used the HARVEST timber
harvest simulator to predict the cumulative effects of four owner groups (two paper companies, a state forest and non-industrial
private owners) with different management objectives on landscape pattern in an upper Michigan landscape managed primarily
for timber production. We quantified trends in landscape pattern metrics that were linked to Montreal Process indicators of
forest sustainability, and used a simple wildlife habitat model to project habitat trends. Our results showed that most trends
were considered favorable for forest sustainability, but that some were not. The proportion of all age classes and some forest
types moved closer to presettlement conditions. The trend for the size of uneven-aged patches was essentially flat while the
average size of patches of the oldest and youngest age classes increased and the size of patches of the remaining age classes
decreased. Forest fragmentation generally declined, but edge density of age classes increased. Late seral forest habitat increased
while early successional habitat declined. The owners use different management systems that cumulatively produce a diversity
of habitats. Our approach provides a tool to evaluate such cumulative effects on other landscapes owned by multiple owners.
The approach holds promise for helping landowner groups develop and evaluate cooperative strategies to improve landscape patterns
for forest sustainability. 相似文献
83.
Twelve male buffalo calves of 10 to 12 months of age were divided into 3 groups of four each. They were fed wheat straw+concentrate
mixture +3 Kg greens. The chemical composition of the diet was same in all the three groups except fluoride which was added
(as NaF) in concentrate mixture of group B and C to make the final fluoride concentration 30 ppm and 60 ppm respectively.
The animals were kept on scheduled diet for a period of 90 days. Body weights were recorded at the start of the experiment
and at fortnightly interval thereafter. Analysis of data revealed that the dry matter intake decreased non significantly in
group B and C as compared to control group. A significant decrease in serum calcium and a significant increase in phosphorus
concentration were observed in group C animals. A significant increase was observed in alkaline phosphatase activity in group
C animals. A non significant decrease was observed in T4 values in group C animals. On the basis of these results it could be concluded that fluoride in the diet of buffalo calves
@ 30 ppm is a safe level whereas 60 ppm has affected the blood metabolites. 相似文献
84.
Robert A. Mccleery 《Landscape Ecology》2009,24(4):483-493
Predator stimuli created by humans in the urban environment may alter animals’ anti-predator behaviors. I hypothesized that
habituation would cause anti-predator behaviors to decrease in urban settings in response to humans. Additionally, I hypothesized
that populations habituated to humans would show reduced responses to other predator stimuli. I observed three populations
of squirrels (urban, suburban and rural) responses to human approaches, red-tailed hawk vocalizations (Buteo jamaicensis) and coyote (Canis latrans) vocalizations. Mahalanobis distances of anti-predator behaviors in response to human approaches were consistent with the
urban–rural gradient. Flight initiation distances (X
2 = 26.33, df = 2, P < 0.001) and amount of time dedicated to anti-predator behavior (X
2 = 10.94, df = 2, P = 0.004) in response to human approaches were also consistent with the urban–rural gradient. Supporting the habituation hypothesis,
naive juvenile squirrels increased flight initiation distances (X
2 = 35.89, df = 1, P < 0.001) and time dedicated to anti-predator behaviors (X
2 = 9.46, df = 1, P = 0.002) relative to adult squirrels in the same urban environment. Time dedicated to anti-predator behaviors differed among
all three sites in response to both coyote (X
2 = 9.83, df = 2, P = 0.007) and hawk (X
2 = 6.50, df = 2, P = 0.035) vocalizations. Responses to both vocalizations on rural sites (coyote = 45%, hawk = 55%) greater than twice that
found on the urban sites (coyote = 11%, hawk = 20%). This is possibly the first case of a transfer of habituation demonstrated
under field conditions. 相似文献
85.
Effects of melatonin on maturation,histone acetylation,autophagy of porcine oocytes and subsequent embryonic development 下载免费PDF全文
Hui Li Renyun Hong Biao Ding Chengxue Liu Di Gao Hui Shang Zubing Cao Weiping Huang Xiaorong Zhang Yunhai Zhang 《Animal Science Journal》2017,88(9):1298-1310
Melatonin (MLT) is an endogenous hormone with roles in animal germ cell development. However, the effect of MLT on porcine oocyte maturation and its underlying mechanisms remain largely unknown. Here, we investigated the effects of exogenous MLT on oocyte maturation, histone acetylation, autophagy and subsequent embryonic development. We found that 1 nmol/L MLT supplemented in maturation medium was the optimal concentration to promote porcine oocyte maturation and subsequent developmental competence and quality of parthenogenetic embryos. Interestingly, the beneficial effects of 1 nmol/L MLT treatment on porcine oocyte maturation and embryo development were mainly attributed to the first half period of in vitro maturation. Simultaneously, MLT treatment could also improve maturation of small follicle‐derived oocytes, morphologically poor (cumulus cell layer ≤1) and even artificially denuded oocytes and their subsequent embryo development. Furthermore, MLT treatment not only could decrease the levels of H3K27ac and H4K16ac in metaphase II (MII) oocytes, but also could increase the expression abundances of genes associated with cumulus cell expansion, meiotic maturation, histone acetylation and autophagy in cumulus cells or MII oocytes. These results indicate that MLT treatment can facilitate porcine oocyte maturation and subsequent embryonic development probably, through improvements in histone acetylation and autophagy in oocytes. 相似文献
86.
Sara Mello Pinho Giovanni Lemos de Mello Kevin M. Fitzsimmons Maurício Gustavo Coelho Emerenciano 《Aquaculture International》2018,26(1):99-112
Aquaponics is emerging as an alternative for high-health food production. Being able to identify the technical viability of non-conventional plants and fish species would help to increase the interest and possibilities in aquaponic systems. The goal of the present study was to evaluate the aquaponics production of two garnish species: scallion (S) and parsley (P), using effluents of pacu and red tilapia culture. Two aquaponics devices were used, differing according to the fish species, generating two different effluents. Thus, for plant performance, four treatments were evaluated in a factorial design (plant species and fish effluent as main factors), as followed: Pacu-S, Tilapia-S, Pacu-P, and Tilapia-P, with three replicates each, for 35 days. Fish performance was evaluated using Student’s t test. Each experimental device included a fish tank, filters, and six experimental units for the plants (floating rafts). Results indicated that feed conversion ratio (FCR) was higher in tilapia as compared to pacu (p < 0.05); however, fish productivity and survival were similar between species. Plant performance parameters were similar with no significant differences regardless of the fish effluent (p > 0.05), except for higher number of leaves per plant in scallion cultured using pacu effluent. Plant performance comparing both plant species indicated that scallion performed better as compared to parsley in all parameters. In addition, scallion also performed better related to the plant quality index. The results indicate that pacu presented a viable alternative for the aquaponics production, and regarding to the garnish, scallion performed better results as compared to parsley. 相似文献
87.
Within the framework of a larger project aimed to assess the potential of second generation hybrid striped bass for German
aquaculture the genotypic segregation of five microsatellite loci was analysed in two progeny lots (n = 74 and 76, respectively). There was no consistent correlation between microsatellite genotypes and phenotypic category
(white bass, hybrid, or striped bass). None of the individuals expressed neither only white bass nor only striped bass genotypes
at all five loci. On the other hand, only hybrid genotypes at all five loci were detected in three individuals of lot 1 and
four individuals of lot 2. Single loci tests for conformity of microsatellite genotypic segregation with Mendelian rules revealed
significant deviations (P < 0.05) in four cases for lot 1 and in three cases for lot 2. If pooled over all five loci, both lots displayed highly significant
deviations (P < 0.01) with an excess of hybrid genotypes and a deficiency of white bass genotypes. It is concluded that stabilizing selection
performed on hybrid genotypes might be a suitable approach for practical aquaculture in Europe if the goal is to become independent
of first generation hybrid fry supply and/or if establishing domesticated brood stocks of both parental species is impossible.
However, more detailed studies on the characteristics and performance of multiple hybrid generations are needed. 相似文献
88.
Kahori Arita Kiyoshi Isowa Takashi Ishikawa Hideo Aoki Hiromi Ohta 《Fisheries Science》2012,78(3):625-630
The post-thaw motility and fertility of Japanese pearl oyster sperm show large variances, even among sperm samples obtained
from the same individuals. This study aimed to clarify the factors that cause such differences. Spermatozoa were diluted 50
times with diluent comprising 10 % methanol, 18 % fetal bovine serum, and 72 % seawater, and dispensed into 0.25 ml straws.
A total of 59 straws were cooled, one by one, at 11 different heights from the surface of liquid nitrogen (LN) to −50 °C,
and then immediately immersed in LN. After thawing the straws, the relationships between the cooling rate and the post-thaw
motility and post-thaw fertility of the spermatozoa were examined. Both the post-thaw motility and the post-thaw fertility
showed a sharp peak when the straws were cooled at around −20 °C/min. There was a strong correlation between post-thaw motility
and fertility (P < 0.001). There was a large difference in the cooling rates and the post-thaw motilities and fertilities of the spermatozoa,
even between straws cooled at the same height. These results indicate that the optimum range for the cooling rate of oyster
spermatozoa is quite narrow, and the method of cooling straws at a fixed distance from the LN surface is unsuitable for the
cryopreservation of Japanese pearl oyster spermatozoa. 相似文献
89.
90.
应用酶消化法(胶原酶消化:0.1%胶原酶Ⅰ型+0.1%BSA;胰蛋白酶消化:0.25%胰蛋白酶+1mM EDTA)和植块法从华南虎皮肤组织中分离成纤维细胞。研究结果表明,植块法较适合分离华南虎皮肤成纤维细胞,胶原酶消化法次之,而胰蛋白酶消化法不宜用于分离华南虎皮肤成纤维细胞。DMEM/F12(1:1)培养基+10%FCS+10 ng/ml EGF+5μg/ml胰岛素+100 IU/ml青霉素+100μg/ml链霉素组成的培养体系适用于华南虎皮肤成纤维细胞的体外培养。 相似文献