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1.
Vegetation History and Archaeobotany - Archaeobotanical research in the southern Levant has focused on the development of agriculture and urban societies, but less so on how agriculture sustained...  相似文献   

2.
The presence of phytoplasmas in declining trees of European hackberry was demonstrated for the first time using polymerase chain reaction assays with primers amplifying phytoplasma 16S rDNA regions. Restriction fragment length polymorphism analysis of these DNA fragments together with PCR, employing primers specific for particular phylogenetic groups of phytoplasmas, made it possible to detect the presence of aster yellows group (16SrI) related phytoplasmas. These were classified into two different subgroups (I-B and I-C) and were present in both symptomatic and asymptomatic hackberry plants. Aster yellows-related phytoplasmas were found in all the root samples collected during the winter. In addition, phytoplasmas from the peach X disease group (16SrIH) were found in four out of 10 root samples; in five root samples phytoplasmas of the elm yellows group (16SrV) were also present.  相似文献   

3.
P. B. Best    H. Rüther 《Journal of Zoology》1992,228(4):595-614
Between July or August and November 1988 and 1989, 72 cow-calf pairs of right whales ( Eubalaena australis ) were measured photogrammetrically from the air off De Hoop, South Africa. Median coefficients of variation ranged from 1.29 to 4.56%, being lowest in cows and calves for measurements of total length. Fifty-seven adult cows measured from 12.37 to 15.54 m in length, with females photographed for the first time with a calf (= primiparous) being smaller than females that had been seen for the first time with a calf at least five years previously. The lengths of 72 calves ranged from 4.53 to 9.24 m, with those from primiparous females being significantly smaller than calves of multiparous females in every month except July. For 37 calves photographed on more than one occasion the growth rate averaged 2.8±0.7 cm per day, with no significant difference between growth rates of calves from primiparous and from other females, and no significant decrease in growth rate between July/September and September/November. Calves grew from an average of 40% of their mother's length in late July to 51% by mid-October. The size distribution of the adult females was no different from that of 25 adult females landed at South African whaling stations between 1911 and 1963 (after adjustment for possible differences in measurement techniques). Five near-term foetuses recovered in June-August in the same whaling operations also agree closely with the size of calves predicted for 1 August. In a comparison with 17 calves stranded or dying accidentally on the South African coast, most of the accidentally caught animals agreed closely in size with the sample of photogrammetrically measured animals, while most of the stranded animals were equal to or smaller in size than the smallest length interval in the photogrammetrically measured animals. The calves of primiparous females may therefore suffer a higher natural mortality rate than those of multiparous females.  相似文献   

4.
The morphology, cell types, and innervation of the several small papillae (x? = 17) and two larger papillae, which together form a ring just outside the fimbriae surrounding the suctorial disc of adult Geotria australis, have been studied using various histological stains, including silver impregnation, and scanning and transmission electron microscopy. The epithelium of all papillae consists almost entirely of mucigenic cells. The multivillous and oligovillous cells, which are found elsewhere in the lamprey epidermis, were not observed, and Merkel and polyvillous cells are rare. Free nerve endings are common, however, in the basal layers of the epidermis. Unlike the small papillae, the two large papillae contain a core of skeletal muscle and a prominent layer of dermal collagen. In the submucosa of these large papillae, the nerves form a dense, compact layer that contains many large and probably sensory axons. It is suggested that the oral disc papillae of adult G. australis are encapsulated mechanosensory structures that play a role in enabling the animal to locate and attach to a suitable point on host fishes or other surfaces.  相似文献   

5.
Peter B.  Best 《Journal of Zoology》1994,232(2):175-189
From the seasonal occurrence of 11 stranded nconates, the earliest and latest observations of possible calving behaviour, and the seasonal incidence of calves in shore-based counts, the extent of the calving season for southern right whales off South Africa can be characterized as from late June to late October, with a peak in August. The occurrence of 89 'new' calves located during monthly photogrammetric flights between July or August and November indicated that 50% were born by 1 September in 1988 and by 15 August in 1989, and that the effective calving season (in which 95.5% of calves are estimated to have been born) lasted 118 days in each year. From regression analysis of the lengths of 221 foetuses and their dates of death, and assuming a mean date of birth of 24 August, the duration of the linear phase of foetal growth is estimated to be 325 days, and the mean size at birth 6-1 m. Uncertainty over the duration of the initial, non-linear phase of foetal growth results in alternative estimates of 357 or 396 days for the total length of gestation. Foetuses of smaller females seem to be conceived later (or experience a longer initial, non-linear phase of foetal growth) than those of larger females. The apparent rarity of adult females in coastal waters in the year in which they are presumed to conceive is attributed to either a brief residence time or the possibility that conceptions may occur well outside coastal waters.  相似文献   

6.
This paper reviews the archaeobotanical record of the transition from foraging to farming in the southern Levant. The concise presentation of the published botanical evidence follows a critical assessment of: (a) the nature of Epipalaeolithic plant management strategies, (b) the place of the southern Levant in the polycentric development of Near Eastern plant cultivation and domestication, and (c) region-specific pathways for the emergence of domesticated crop “packages”. Some inferences are drawn and suggestions are made concerning the potential contribution of archaeobotanical research to questions of broader archaeological significance about socio-economic change in the southern Levant during the Pre-pottery Neolithic.  相似文献   

7.
Electrophoretic data for 15 enzymes encoded by 18 loci were analysed in samples of larval lampreys from two southern hemisphere species (Geotria australis and Mordacia mordax). Low values for Nei genetic distance coefficients for all loci in populations of G. australis from Western Australia, Tasmania and New Zealand (0.0013 to 0.0058) suggest that adults may intermix over distances greater than 4000 km. The average heterozygosity for four populations of G. australis (0.086) was much greater than for two populations of the far less widely distributed M. mordax (0.021).  相似文献   

8.
Abstract This study investigates the importance of climate as a factor influencing the southern distributional limit of the common blossom bat (Syconycteris australis). Using the climatic predictive model BIOCLIM and 73 locality records, 5. australis was predicted to have a coastal distribution in eastern Australia, where winter temperatures are relatively warm and moist conditions prevail throughout the year. The actual southern limit of S. australis, determined by mist-netting suitable habitats, was found to be at Booti-Booti (32°19'S 152°3l'E) on the mid-north coast of New South Wales. BIOCLIM predicted the southerly limit of 5. australis to be 150–200km further south of their actual limit. Booti-Booti was occupied at relatively low levels of abundance year round, while the abundance of S. australis at a site 50 km to the north was much greater, fluctuating with changes in Banksia flower numbers. Seasonal range extensions beyond Booti-Booti were not detected, despite the availability of apparently suitable habitat at Myall Lakes only 20–35 km further south. Metabolic costs of S. australis at Booti-Booti were estimated to exceed basal metabolic rate (BMR) by 4.5 times, well above the physiologically predicted limit of 2.5 times BMR. These results, together with the lack of range extensions and the close correspondence of BIOCLIM'S predicted southern limit of S. australis with their actual limit, suggest that the bat's southern distribution is limited by cold, wet winters and dry summers.  相似文献   

9.
This study demonstrates that the silver technique of Grimelius (Acta Soc. Med. Ups. 73:243–270, 68) is ideally suited for the study of cardiovascular chromaffin cells in lampreys. This method showed that in the Southern Hemisphere lamprey, Geotria australis, the distribution of chromaffin cells differs from that described for holarctic species. In G. australis, the chromaffin cells are found mainly in the sinus venosus, atrium, and nearby regions of the cardinal and jugular veins, and they are absent from the ventricle and conus arteriosus. The location and discreteness of the large accumulation of chromaffin cells in the lateral wall of the right posterior cardinal vein of adults resemble those of the precardiac axillary bodies of elasmobranchs. Chromaffin cells become more abundant during metamorphosis. The possible phylogenetic and functional significance of lamprey chromaffin cells is briefly discussed.  相似文献   

10.
Abstract

During the 19th century, sail whalers hunted right whales throughout the southern oceans north of 50 degrees. This review seeks to document the recovery of southern right whales by comparing the northernmost recent sightings with older sightings that survive “fossilised” in historical records of the sail whaling era. Despite a steady expansion northwards in recent years, the present distribution of right whales is still far short of that recorded by sail whalers over a century ago.  相似文献   

11.
The duration and timing of coastal residence of individually identified southern right whales at a principal aggregation area on the southern Australian coast differed markedly between females with calves and unaccompanied whales. The mean residence period of females that calved within the aggregation area was 70.9 days, with mean residence mid-points of 20 August in 1993 and 22 August in 1994. In contrast, unaccompanied adults remained resident for an average of only 20.4 days with mean residence mid-points of 27 July and 11 August in 1993 and 1994, respectively. Whales have been sighted at this aggregation area from mid May to late October (approx. 160 days), although the effective calving season (95-100% of calves born) lasted only 88 days in 1993 and 96 days in 1994. The mean birth date based on first sighting with neonatal calf, and corrected for sightability bias, was 15 July in 1993 and 17 July in 1994, with 100% of calves born before 31 August 1993 and 23 September 1994.
The time between birth and dispersal from the aggregation area, at or just prior to the commencement of the southward migration, was highly variable. Calves bom before the mean calving date averaged 80 days within the aggregation area, twice as long as those born after the mean (40 days). The large number of calves estimated to be less than 14 days old at first sighting, combined with the sighting of 26 pregnant females prior to parturition, suggests the majority of births occurred within, or very near to, the aggregation area.  相似文献   

12.
Cytotoxic triterpenes from the twigs of Celtis philippinensis   总被引:2,自引:0,他引:2  
Two triterpene esters, 3beta-trans-sinapoyloxylup-20(29)-en-28-ol (1) and 3beta-trans-feruloyloxy-16 beta-hydroxylup-20(29)-ene (2), were isolated as cytotoxic constituents from the chloroform-soluble extract of the twigs of Celtis philippinensis, along with five known triterpenes, 3beta-O-(E)-feruloylbetulin (3), 3beta-O-(E)-coumaroylbetulin (4), betulin (5), 20-epibryonolic acid (6), and ursolic acid (7). The structures of 1 and 2 were assigned from their 1D and 2D NMR spectroscopic data. All isolates were evaluated for cytotoxicity against several human cancer cell lines.  相似文献   

13.
Five microsatellite loci were isolated and characterized for the southern pygmy perch, Nannoperca australis, a regionally vulnerable Australian freshwater fish. Screening of 22 individuals from southeastern Australia revealed four to 15 alleles per locus, and observed levels of heterozygosity ranged from 0.09 to 0.45. All loci conformed to Hardy–Weinberg proportions and were in linkage equilibrium.  相似文献   

14.
Sea surface temperature (SST) time-series from the southwest Atlantic and the El Ni?o 4 region in the western Pacific were compared to an index of annual calving success of the southern right whale (Eubalaena australis) breeding in Argentina. There was a strong relationship between right whale calving output and SST anomalies at South Georgia in the autumn of the previous year and also with mean El Ni?o 4 SST anomalies delayed by 6 years. These results extend similar observations from other krill predators and show clear linkages between global climate signals and the biological processes affecting whale population dynamics.  相似文献   

15.
In the deepest section of a large complex cave in the northern Negev desert, Israel, a bi-conical lead object was found logged onto a wooden shaft. Associated material remains and radiocarbon dating of the shaft place the object within the Late Chalcolithic period, at the late 5th millennium BCE. Based on chemical and lead isotope analysis, we show that this unique object was made of almost pure metallic lead, likely smelted from lead ores originating in the Taurus range in Anatolia. Either the finished object, or the raw material, was brought to the southern Levant, adding another major component to the already-rich Late Chalcolithic metallurgical corpus known to-date. The paper also discusses possible uses of the object, suggesting that it may have been used as a spindle whorl, at least towards its deposition.  相似文献   

16.
This study explored population dynamics of Sepioteuthis australis on a fine temporal scale before, during, and after a 3-month commercial fishing closure on the summer inshore spawning grounds of Great Oyster Bay, Tasmania, Australia. An abrupt change in male size (mantle length) and population sex ratio after the re-opening of the commercial fishery suggests that fishing alters the population structure on the spawning beds from a ‘natural’ structure which is highly biased towards males, to a more even ratio of males to females. Although jigs are taking a representative sample of the squid population using the spawning beds at any one time, the fishery is apparently still effectively selective for males, potentially as a function of differential spawning movements of the two sexes. Increased fishing pressure over the past 5 years had been correlated with a change towards a highly male-biased sex ratio on the spawning beds; however the current study suggests that increased fishing pressure in recent years may not have reduced the proportion of females. Instead, the inter-annual change in sex ratio may reflect changes in the degree of protection from fishing, with progressively longer closures allowing time for more males to accumulate on the beds and therefore, for the proportion of males to increase (as opposed to a decrease of females). As fishing is selective for males, fishing throughout the spawning season could potentially modify the process of sexual selection and the mating behaviors of the individuals within the spawning population, highlighting the need for closures over this crucial period. Additionally, examinations and comparisons of squid population structure need to be interpreted in light of fishing pressure and broader movement patterns.  相似文献   

17.
The location and arrangement of the pancreatic endocrine tissue in larval and adult Geotria australis (Geotriidae) differ markedly from those exhibited by the comparable stages of Northern Hemisphere lampreys (Petromyzontidae). In larval Geotria australis, the main zones of islet proliferation are located laterally between the oesophagus and the inner edge of the two large intestinal diverticula unique to this species rather than dorsal and ventral to the oesophagus. In adult Geotria australis, the islet follicles are closely packed into a single discrete capsule which could be easily removed surgically, rather than into cranial, intermediate, and caudal cords. The differences in the adult can be related to a lack of involvement of the bile duct in islet formation during metamorphosis. While B cells were found in both larval and adult islet follicles, the PI acidophilic cells and argyrophilic cells, which appeared respectively at stages 3 and 4 in metamorphosis, were present in all adult stages.  相似文献   

18.
We investigated leaf and shoot architecture in relation to growth irradiance (Qint) in young and mature trees of a New Zealand native gymnosperm Agathis australis (D. Don) Lindl. to determine tree size-dependent and age-dependent controls on light interception efficiency. A binomial 3-D turbid medium model was constructed to distinguish between differences in shoot light interception efficiency due to variations in leaf area density, angular distribution and leaf aggregation. Because of the positive effect of light on leaf dry mass per area (MA), nitrogen content per area (NA) increased with increasing irradiance in both young and mature trees. At a common irradiance, NA, MA and the components of MA, density and thickness, were larger in mature trees, indicating a greater accumulation of photosynthetic biomass per unit area, but also a larger fraction of support biomass in older trees. In both young and mature trees, shoot inclination angle relative to horizontal, and leaf number per unit stem length decreased, and silhouette to total leaf area ratio (SS) increased with decreasing irradiance, demonstrating more efficient light harvesting in low light. The shoots of young trees were more horizontal and less densely leafed with a larger SS than those of mature trees, signifying greater light interception efficiency in young plants. Superior light harvesting in young trees resulted from more planar leaf arrangement and less clumped foliage. These results suggest that the age-dependent and/or size-dependent decreases in stand productivity may partly result from reduced light interception efficiency in larger mature relative to smaller and younger plants.  相似文献   

19.
Microremains of various sharks, actinopterygians and crocodiles have been recovered from two sites in the Douiret Formation and three sites in the Aïn el Guettar Formation in southern Tunisia. The presence of an actinistian is also suggested based on histological study of hemisegments of lepidotrichia. Convergence in dental enameloid microstructure between neoselachian sharks and actinopterygians sharing a tearing dentition is also documented. The vertebrate assemblage of the Douiret Formation suggests a pre-Aptian age for this formation and the presence of Bernissartia in the Aïn el Guettar Formation confirms faunal exchange between Africa and Europa during the Early Cretaceous.  相似文献   

20.
In recent years, the study of percussive, pounding and grinding tools has provided new insights into human evolution, more particularly regarding the development of technology enabling the processing and exploitation of plant resources. Some of these studies focus on early evidence for flour production, an activity frequently perceived as an important step in the evolution of plant exploitation. The present paper investigates plant food preparation in mobile hunter-gatherer societies from the Southern Levant. The analysis consists of a use-wear study of 18 tools recovered from Ohalo II, a 23 000-year-old site in Israel showing an exceptional level of preservation. Our sample includes a slab previously interpreted as a lower implement used for producing flour, based on the presence of cereal starch residues. The use-wear data we have obtained provide crucial information about the function of this and other percussive tools at Ohalo II, as well as on investment in tool manufacture, discard strategies and evidence for plant processing in the Late Pleistocene. The use-wear analysis indicates that the production of flour was a sporadic activity at Ohalo II, predating by thousands of years the onset of routine processing of plant foods.  相似文献   

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