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1.
The objective of the study was to establish an effective ovarian superstimulatory protocol and subsequently obtain oocytes from bison by transvaginal ultrasound-guided follicular aspiration. Two experiments involving 22 wood bison were done during the breeding season (September to December). In experiment 1, the bison were given a luteolytic dose of prostaglandin (Day 0) and underwent follicular ablation (Day 8) to induce ovarian synchrony. Synchronized bison were then assigned randomly to two groups (n = 11 per group) and given either 200 mg FSH diluted in saline sc, or 200 mg FSH diluted in a proprietary slow-release formulation (SRF) im on Days 9 and 11. Prostaglandin was given to both groups on Day 11 followed by 25 mg LH on Day 13. Oocytes were collected by transvaginal ultrasound-guided aspiration of follicles ≥5 mm on Day 14. In experiment 2, bison were synchronized as in experiment 1 and assigned randomly to one of two groups (n = 11 per group) and given either a single dose of 2500 IU eCG im on Day 9, or 200 mg FSH sc on Days 9 and 11. Prostaglandin was given to both groups on Day 11, and LH (25 mg) was given on Day 13. Oocyte collection was done as described in experiment 1. Cumulus-oocyte-complexes (COC) were classified according to morphologic characteristics. In experiment 1, more follicles ≥5 mm were detected on Day 14 in bison treated with FSH versus eCG (12.2 ± 1.73 vs. 5.8 ± 0.52; P < 0.05), and more COC were collected from FSH-treated animals (7.2 ± 1.41 vs. 3.4 ± 0.62; P < 0.05). In experiment 2, the FSH-saline and FSH-SRF groups had a similar number (mean value ± standard error of the mean) of follicles ≥5 mm on Day 14 (12.4 ± 1.49 vs. 13.8 ± 1.24, respectively) and a similar number of COC were collected (6.5 ± 1.13 vs. 6.3 ± 0.96, respectively). The proportion of COC collected per follicle aspirated and the percentage of compact, expanded, and denuded oocytes did not differ between groups in either experiment 1 or 2. In summary, a two-dose regimen of FSH diluted in saline and given sc or in a SRF and given im induced a similar ovarian response in wood bison, whereas a single dose of eCG resulted in a significantly lower ovarian response. Overall, COC were collected from 55% of follicles after transvaginal, ultrasound-guided needle aspiration in wood bison.  相似文献   

2.
The paper presents results of the charcoal analysis from the lakeshore settlement of Chalain 4 in the French Jura (Dép. Franche-Comté), dated by dendrochronology from 3040 to 3000 bc. The investigated material comes from waterlogged organic layers (excluding fire events) where charcoals are assumed to be the residues of domestic fires only. The anthracological (charcoal) analysis reveals a complex domestic firewood management in balance with the social organisation and the technical and economic systems of the settlement. This firewood economy is characterised by the avoidance of wood species intended for other activities, such as building or foddering, and by the preferential use of wood less than 10 cm in diameter. The areas from which firewood was obtained are also connected to woodland clearance for cultivated land, which suggests that firewood was gathered along the paths, which were travelled daily.  相似文献   

3.
Two experiments were done to develop an effective superovulatory treatment protocol in wood bison for the purpose of embryo collection and transfer. In experiment 1, donor bison were assigned randomly to four treatment groups (N = 5 per group) to examine the effects of method of synchronization (follicular ablation vs. estradiol-progesterone treatment) and ovarian follicular superstimulation (single slow-release vs. split dose of FSH). Recipient bison were synchronized with donor bison by either follicular ablation (N = 8) or estradiol-progesterone treatment (N = 9). In experiment 2, bison were assigned randomly to four treatment groups (N = 5 per group) to examine the ovarian response to two versus four doses of FSH, and the effect of progesterone (ovarian superstimulation with or without an intravaginal progesterone-releasing device). Donor bison were inseminated with fresh chilled wood bison semen 12 and 24 hours after treatment with GnRH (experiment 1) or LH (experiment 2). The ovarian response was assessed using ultrasonography. In experiment 1, the number of large follicles (≥7 mm) increased in response to both FSH treatments, but the diameter of the largest follicle detected 4 and 5 days after the start of ovarian superstimulation was greater in bison treated with a single dose of FSH than in those treated with two doses (P < 0.05). A total of 10 ova and/or embryos were collected. One blastocyst was transferred to each of five recipient bison resulting in the birth of two live wood bison calves. In experiment 2, two doses of FSH resulted in a greater number of large follicles (≥9 mm) on Days 4, 5, and 6 (P < 0.05) after beginning of superstimulation (Day 0), and more ovulations than four doses of FSH (11.2 ± 2.4 vs. 6.4 ± 0.8; P < 0.05). Embryo collection was performed on only five donors, and a total of 19 ova and/or embryos were recovered. In summary, fewer FSH treatments were as good or better than multiple treatments, consistent with the notion that minimizing handling stress improves the superovulatory response in bison. Follicular ablation and estradiol plus progesterone treatment were effective for inducing ovarian synchronization in embryo donor and recipient bison, and an intravaginal progesterone-releasing device during superstimulatory treatment did not influence the superovulatory response or embryo collection. Delaying ovulation-inducing treatment (GnRH or LH) to 5 days after superstimulatory treatment resulted in a greater number of ovulations and improved embryo collection efficiency (experiment 2). Embryo collection and transfer resulted in live offspring from wild wood bison.  相似文献   

4.
A simple and accurate model of high-temperature treatment of wood can assist in the process design and the evaluation of performance of equipment. The high-temperature treatment of wood is essentially a drying process under linearly-increased gas temperature up to final temperature of 220-230 °C which is a challenging process to model. This study is aimed to assess the applicability and accuracy of the reaction engineering approach (REA) to model the heat treatment of wood. In order to describe the process using the REA, the maximum activation energy (ΔEv,b) is evaluated according to the corresponding external conditions during the heat treatment. Results indicate that the REA coupled with the heat balance describes both moisture content and temperature profiles during the heat treatment very well. A good agreement towards the experimental data is indicated. It has also been shown that the current model is highly comparable in accuracy with the complex models.  相似文献   

5.
栖息地状况对小型兽类种群动态具有明显影响。在质量好,食物资源丰富,隐蔽条件优良的栖息地中小型兽类具有较高的存活率,种群繁殖时间更长,体重比较高。有关栖息地和种群动态方面国内外已有研究报道(Brown,1988;Corp et al.,1997;Quinn et al.,2003;Schnurr et al.,2004)。  相似文献   

6.
《Dendrochronologia》2014,32(4):295-302
In this study, wood anatomy, tree-ring width and wood density of Pinus sylvestris at the northern timberline in Fennoscandia were used to identify relationships among the parameters and to screen them for their climatic signals. Furthermore we investigated the influence of the juvenile wood section for all parameters developed. The measurements of wood anatomy were conducted with confocal laser scanning microscopy (CLSM) while the density profiles were produced using an Itrax MultiScanner. We developed chronologies of ring width, wood density and anatomy for a period between 1940 and 2010. Correlations between wood density and wood anatomy were strong in the latewood part. For some wood anatomy and density chronologies youth trends were found in the juvenile part. Wood density decreased from the pith up to the 9th ring and stabilized afterwards, while cell lumen diameter and lumen area increased simultaneously up to the 15th ring. All chronologies contained strong summer temperature signals. The wood anatomical variables provided additional information about seasonal precipitation which could not be found in wood density and tree-ring widths. Our study confirmed previous results stating that the parameter maximum density contains the strongest climate signal, that is, summer temperatures at the northern timberline. Nevertheless, the intra-annual data on tracheid dimensions showed good potential to supply seasonal climatic information and improve our understanding of climatic effects on tree growth and wood formation.  相似文献   

7.
This study examines the effect of methodological choices to determine the carbon payback time and the offset parity point for wood pellet production from softwood plantations in the South‐eastern United States. Using the carbon accounting model GORCAM we model low‐, medium‐ and high‐intensity plantation management scenarios for a single stand level, an increasing stand level and a landscape level. Other variables are the fossil‐fuel reference system and the electrical conversion efficiency. Due to the large amount of possible methodological choices and reference systems, there is a wide range of payback times (≤1 year at landscape to 27 years at stand level) and offset parity points (2–106 years). Important aspects impacting on the carbon balances are yield, carbon replacement factor, system boundaries and the choice of reference scenario used to determine the parity point. We consider the landscape‐level carbon debt approach more appropriate for the situation in the South‐eastern United States, where softwood plantation is already in existence, and under this precondition, we conclude that the issue of carbon payback is basically nonexistent. If comparison against a protection scenario is deemed realistic and policy relevant, and assuming that wood pellets directly replace coal in an average coal power plant, the carbon offset parity point is in the range 12–46 years; i.e. one or two rotations. Switching to intensively managed plantations yields most drastic reduction in the time to parity points (≤17 years in 9 of 12 cases).  相似文献   

8.
Ecological wood anatomy ofAlnus nepalensis (Betulaceae) in East Nepal   总被引:1,自引:0,他引:1  
Wood anatomical characters ofAlnus nepalensis growing in East Nepal are evaluated against three non-anatomical factors: tree height, diameter at breast height (DBH), and altitude. Samples were taken from the outermost part of the trunk of five canopy trees at 11 localities between 790 and 2,740 m above sea level. Tree height ranged from 10 to 28 m, and DBH ranged from 15 to 80 cm. Altitude and tree height are correlated with all the vessel characters studied. Among wood anatomical characters, vessel characters measured from cross sections are strongly correlated with one another, and are also correlated with vessel element and fiber-tracheid length. Multiple regression analysis using non-anatomical factors as independent variables resulted in significant correlation at 1% level in all pore characters, vessel element length, perforation plate bar number, and fibertracheid length. Regression coefficients of significant regressions are usually largest for altitude. For wood structure ofAlnus nepalensis in East Nepal, 23 to 42% of the variation is affected by non-anatomical factors. The large contribution of altitude is considered to be an indirect measure of the effect of temperature.  相似文献   

9.
To investigate the potential of Norway spruce (Picea abies L. Karst) as a palaeoclimate archive in the southeastern European Alps, tree ring chronologies were developed from trees growing at two sites in Slovenia which differed in their ecological and climatological characteristics. Ring width, maximum latewood density, annual height increment and latewood cellulose carbon isotope composition were determined at both sites and the resulting time-series compared with and verified against instrumental climate data for their common period (AD 1960–AD 2002). Results indicate that ring width sensitivity to summer temperature is very site-dependent, with opposing responses at alpine and lowland sites. Maximum density responds to September temperatures, indicating lignification after cell division has ceased. Stable carbon isotopes have most potential, responding strongly to summer temperature in both alpine and lowland stands. Height increment appears relatively insensitive to climate, and is likely to be dominated by local stand dynamics.  相似文献   

10.
Wang X  Li H  Cao Y  Tang Q 《Bioresource technology》2011,102(17):7959-7965
In the present study, 1-allyl-3-methylimidazolium chloride (AmimCl), an ionic liquid (IL), was used to extract cellulose from pine, poplar, Chinese parasol, and catalpa wood chips. Results show that pine is the most suitable wood species for cellulose extraction with ILs. Its cellulose extraction rate can reach as high as 62% under optimized conditions and its cellulose content is as high as 85% when DMSO/water is used as the precipitant. The dissolution process can be clearly observed by hot stage optical microscopy, and the reaction time can be significantly reduced by microwave irradiation. 13C CP/MAS NMR, FTIR, XRD, and SEM were used to analyze the cellulose-rich extracts of pine. Results show that IL dissolves pine wood by destroying inter and intramolecular hydrogen bonds between lignocelluloses. The major component of pine extract is cellulose with a homogeneous and dense structure. After extraction, AmimCl can be easily recycled and reused.  相似文献   

11.
Charcoal analysis was carried out as part of an interdisciplinary project focusing on the copper mining history of the former mining area of Schwaz and Brixlegg, a region pivotal as a copper source in prehistoric Europe. The goal was to use remains of carbonised wood to investigate environmental implications of prehistoric mining, as well as to gain new insight about the ancient mining technique of fire-setting. Charcoal samples from seven copper mining sites (Late Bronze Age to Early Iron Age) were analysed. The results reveal a strong preference for coniferous wood as fuel in fire-setting, but not in ore smelting/roasting processes. Species composition at the ore-processing sites indicates moderate forest degradation processes caused by human intervention.  相似文献   

12.
The type of samples most commonly used in dendro sciences are increment cores of conifers. These cores allow for an easy determination and measurement of ring-width variations over long time periods. For wood anatomical analyses, the cores have to be split into pieces to enable the preparation of high quality micro sections for detailed measurements of cell properties. A major drawback of this procedure is the fact that it is labor intensive and time consuming. We present a new technique enabling the preparation of micro sections of entire increment cores up to a length of 40 cm. For that purpose we combined standard wood-anatomical techniques with the application of Mowiol glue and common Tesa tape. We tested the introduced method on increment cores of Larix decidua Mill. sampled years ago for ring-width analyses to reanalyze them on a microscopic level. The ability to cut these long sections will tremendously reduce the time needed to prepare micro sections. This is of special interest for wood anatomical image analyses of cores used before to create long ring-width chronologies for any kind of environmental reconstructions.  相似文献   

13.
14.
Hot water extraction of wood at elevated temperatures may be a suitable method to produce hemicellulose-lean pulps and to recover xylan-derived products from the water extract. In this study, water extractions of birch wood were conducted at temperatures between 180 and 240 °C in a batch reactor. Xylan was extensively removed, whereas cellulose was partly degraded only at temperatures above 180 °C. Under severe extraction conditions, acetic acid content in the water extract was higher than the corresponding amount of acetyl groups in wood. In addition to oligo- and monosaccharides, considerable amounts of furfural and 5-hydroxymethylfurfural (HMF) were recovered from the extracts. After reaching a maximum, the furfural yield remained constant with increasing extraction time. This maximum slightly decreased with increasing extraction temperature, suggesting the preferential formation of secondary degradation products from xylose. Kinetic models fitting experimental data are proposed to explain degradation and conversion reactions of xylan and glucan.  相似文献   

15.
Piloderma sp., a wood ash-colonizing ectomycorrhizal (EM) fungus, was grown symbiotically with Norway spruce in microcosms which contained granules of hardened wood ash. Mycelium close to the granules was sampled 3 times over a period of 11 weeks and the elemental content was investigated with particle induced X-ray emission. Mycelium from microcosms without wood ash was used as controls. The contents of P and K were similar in mycelium growing close to wood ash granules to those in control mycelium, while the Ca content increased from 23±21 mg g–1 in controls to 63±8 mg g–1 in mycelium growing close to wood ash granules. The Ca content was also increased in other parts of the mycelium more distant from the wood ash. Piloderma sp. may have a role in the short-term storage of Ca released from wood ash, rather than in releasing and storing P.  相似文献   

16.
The dinoflagellate genus Bysmatrum encompasses five epibenthic or tide-pool species and has been characterized by separated anterior intercalary plates. In the present study, we obtained six strains of Bysmatrum from the South China Sea and French Atlantic coast by isolating single cells/cysts from plankton and sediment samples. All strains were examined with light microscopy and scanning electron microscopy. Based on morphological observations, three strains were identified as Bysmatrum subsalsum, characterized by the elongated and rectangular first and a hexagonal second anterior intercalary plate. They differ from each other in the number of sulcal lists and the configuration of the first anterior intercalary plate. One strain was identified as Bysmatrum gregarium and the other two as Bysmatrum granulosum. The cyst-theca relationship of B. subsalsum from the French Atlantic was established by incubation of the cyst, and the geochemical composition of the cyst wall was measured through micro-Fourier transform infrared spectroscopy. Bysmatrum subsalsum from Malaysia shows a bright red stigma in the sulcal area under light microscopy, which was confirmed with transmission electron microscopy: it was identified as a type B eyespot. Small subunit ribosomal DNA (SSU rDNA), partial large subunit ribosomal DNA (LSU rDNA) and internal transcribed spacer (ITS) sequences were obtained from all six strains. The maximum likelihood and Bayesian inference analysis based on concatenated SSU, ITS and LSU sequences revealed that Bysmatrum is monophyletic and nested within Peridiniales. Our strains of B. subsalsum form a new ribotype in the molecular phylogeny (designated as ribotype B). The genetic distance based on ITS sequences among Bysmatrum species ranged from 0.34 to 0.47 and those genetic distances at the intraspecific level of B. subsalsum could reach 0.41, supporting the possibility of hidden crypticity within B. subsalsum.  相似文献   

17.
The most economically important wood boring Crustacea belong to the isopod families Sphaeromatidae and Limnoriidae, both of which have been recently revised and a number of new species have been recognised. Other wood boring crustaceans have now been recognised from tropical mangrove sites. Limnoriids are found from temperate to tropical waters, but appear to be restricted to waters with salinities close to that of seawater. Wood-boring species of Sphaeroma on the other hand can tolerate extremely low salinities, but are restricted to sub-tropical and tropical waters. Approaches to borer control that have proved effective against teredinids (use of naturally durable timber, copper-chrome-arsenic or creosote treatment, surface coatings) have been found under certain circumstances to be ineffective against Limnoria and Sphaeroma. A number of additives to conventional preservatives have been tested, with some insecticides showing evidence of enhancing Limnoria control. The question of crustacean borer nutrition may hold the key to problems of their control. Sphaeromatid borers are capable of filter-feeding and thus may never ingest the treatments applied to wood. Limnoriids do ingest wood, but the role of wood degrading tunneling bacteria, and soft-rotting ascomycete and deuteromycete fungi occurring in the wood they digest remains to be fully elucidated. The source or sources of wood-degrading enzymes that permit digestion of wood particles requires further investigation. The microecology of borer burrows has an important bearing on the availability of nitrogen for borers. Further insights into the problems posed by these borers may be obtained with a better understanding of their ecology. A better testing protocol for preservatives has been developed as a result of knowledge of the natural vertical distribution of Sphaeroma. Behavioural studies indicate that settlement on wood by Limnoria is enhanced by factors derived from conspecifics and from wood-inhabiting microorganisms.  相似文献   

18.
Summary We investigated kin recognition by larval wood frogs (Rana sylvatica) in blind laboratory experiments using spatial affinity as a recognition assay. Tadpoles reared with full-sibs displayed a significant preference for familiar full-sibs over unfamiliar non-kin, but failed to discriminate between unfamiliar full-sibs and unfamiliar paternal half-sibs. Tadpoles reared in social isolation (with or without maternal egg jelly) from the two-celled embryonic stage displayed a significant preference for unfamiliar full-sibs over unfamiliar non-kin. Tadpoles reared on a meat diet with their full-sibs: 1) exhibited a significant preference for unfamiliar full-sibs fed meat over unfamiliar non-kin fed meat, 2) failed to discriminate between unfamiliar full-sibs fed lettuce and unfamiliar non-kin fed meat, 3) exhibited a significant preference for unfamiliar non-kin fed meat over unfamiliar non-lin fed lettuce, 4) failed to discriminate between unfamiliar full-sibs fed meat and unfamiliar full-sibs fed lettuce, and 5) displayed a significant spatial preference for odors associated with meat (a familiar food) over odors associated with lettuce (an unfamiliar food). Our results, together with those of Cornell et al. (1989), indicate that the recognition cue of larval R. sylvatica has both genetic and environmental (dietary) components. Our findings establish that previous exposure to maternal egg jelly, kin, or conspecifics is not necessary for the development of kin recognition ability in larval R. sylvatica. Our results are more consistent with the self-learning of recognition cues (a form of phenotype matching) than with a recognition mechanism that involves a genetically fixed recognition template. Finally, our results indicate that increasing similarity between the recognition template and perceived cue does not necessarily result in increasing spatial affinity for kin.  相似文献   

19.
A comparative study on the decomposition of Japanese red pine wood under subcritical water conditions in the presence and absence of phosphate buffer was investigated in a batch-type reaction vessel. Since cellulose makes up more than 40-45% of the components found in most wood species, a series of experiments were also carried out using pure cellulose as a model for woody biomass. Several parameters such as temperature and residence time, as well as pH effects, were investigated in detail. The best temperature for decomposition and hydrolysis of pure cellulose was found around 270 °C. The effects of the initial pH of the solution which ranged from 1.5 to 6.5 were studied. It was found that the pH has a considerable effect on the hydrolysis and decomposition of the cellulose. Several products in the aqueous phase were identified and quantified. The conditions obtained from the subcritical water treatment of pure cellulose were applied for the Japanese red pine wood chips. As a result, even in the absence of acid catalyst, a large amount of wood sample was hydrolyzed in water; however, by using phosphate buffer at pH 2, there was an increase in the hydrolysis and dissolution of the wood chips. In addition to the water-soluble phase, acetone-soluble and water-acetone-insoluble phases were also isolated after subcritical water treatment (which can be attributed mainly to the degraded lignin, tar, and unreacted wood chips, respectively). The initial wood:acid ratio in the case of reactions catalyzed by phosphate buffer was also investigated. The results showed that this weight ratio can be as high as 3:1 without changing the catalytic activity. The size of the wood chips as one of the most important experimental parameters was also investigated.  相似文献   

20.
In this paper, formation of unique carbon nanostructures via carbonization of wood in a step-wise process is reviewed. The mechanism described for the production of carbon nanotubes improves our understanding of a historic mystery related to the production of Damascus steel.  相似文献   

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