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191.
A new genus and species of phreatoicidean isopod, Crenisopus acinifer, has been collected from a freshwater spring in the northern Kimberley region of Western Australia. Empirical cladistic analysis of 10 exemplars of phreatoicidean genera found a single cladogram. The new genus and species assumed a basal position in the Phreatoicidea, placing it within the family Amphisopodidae sensu lata. This family, however, was not monophyletic in the preliminary cladogram, suggesting that the taxonomic structure of the suborder must be revised. The cladogram provided evidence for the monophyly of the Phreatoicidae and its New Zealand clade. The analysis suggested that clades of modern phreatoicideans diverged from one another during the Mesozoic Era after they entered fresh water, but prior to the fragmentation of East Gondwana.  相似文献   
192.
Larval therapy, the therapeutic use of blowfly larvae to treat chronic wounds, is primarily used in debridement. There are, however, gaps in current knowledge of the optimal clinical application of the therapy and mechanisms of action in the debridement process. Using an artificial assay, two studies were undertaken to investigate these aspects of larval debridement by Lucilia sericata Meigen (Diptera: Calliphoridae); the first studied the effects of the density of larvae on tissue digestion and larval mass, and the second considered the effects on the same parameters of incorporating protease inhibitors into the feeding substrate. The total mass of tissue digested increased with larval density until saturation was observed at 5.0–7.5 larvae/cm2. This range was considered optimal as lower doses resulted in the removal of less tissue and higher doses offered no additional tissue removal and appeared to exacerbate competition for feeding. In the second study, increased protease inhibitor concentration led to significant decreases in tissue digestion and larval mass, suggesting that serine proteases, particularly trypsin, may play major roles in larval digestion. Such information is important in elucidating the main constituents that make up larval digestive products and may be significant in the development of new therapies.  相似文献   
193.
Ricinus communis L. var. Gibsonii was grown in Long Ashton nutrientmedium with either 12mol m–3 NO3 or 8.0 mol m–3NH+4 as N source. Two plants from each N treatment were harvestedtwice a week and analysed for C, N, P, S, NO3, SO2–4ClK+Na+, Ca2+ Mg2+ and ash alkalinity. Statistical analysis of thedata showed that the effect of age and N source was differentfor the chemical variables analysed. Thus [Na+] was unaffectedby age or N source, and for both N sources [Mg2+] started atthe same level and decreased at the same rate as the plantsmatured. With NH+4 as N source, [SO2–4] was higher thanwith NO3, but did not alter with age. The concentrations,in mmol g–1 dry wt, of C, organic N, K+ and Ca2+ weredifferent for the two N sources, but the levels of these variablesaltered with age in the same way for both N sources; i.e. therewas no age x N interaction. In the case of P, NO3, Cl and COO, however,age-related variations were different for the two N sources.It is concluded, inter alia, that [Na+] is determined by external[Na+] alone, and that K+, Ca2+ and Cl are the inorganicions actively involved in charge balance during ion uptake bythe roots. Key words: Ontogeny, Chemical composition, Plant nutrition  相似文献   
194.
The Energetic Costs of Fighting   总被引:1,自引:0,他引:1  
SYNOPSIS. Current evolutionary theory predicts that energy expenditurewill be adjusted in contest situations to the value of the disputedresource and the relative probability of winningit. Estimatesof energy expended in contest situations support this prediction.I report on theenergetic costs of display relative to othercontest costs to individual fitness (e.g., risk ofpredation,losses in feeding time, injury and mortality) in territorialdisputes of the spider Agelenopsis aperta. Cost estimates obtainedin terms of decrements to milligrams wet-weight of future eggproduction resulting from single contests indicatethat actualenergy expenditure inthese territorial disputes represent insignificantcosts. Thesecosts are, in fact, 5–6 orders of magnitudesmaller than the costs associated with injury, potential predationand even loss infood as a result of time spent in the interactions.Review of the literature indicates that in most instances, energyexpenditure may be correlated with some other factor upon whichselection is acting (e.g., short contests wherepredation riskis high, variation in levels of escalation exhibited). Two exceptionsinclude the tremendous losses of workers to reproductives inant, termite, and bee colony territorial disputes and the productionof specializedagonistic organsexhibited by some corals, seaanemones and corallimopharians when encountering neighbors within"territorial"boundaries.  相似文献   
195.
ABSTRACT A new species of coccidium, Tyzzeria chalcides, is described from the ocellated skink, Chalcides ocellatus, from Egypt. Meronts occur in the epithelial cells of the bile ducts and gamonts within the epithelial cells of the gall bladder. Fully sporulated oocysts are cylindrical (L/W ratio 1.88) without a micropyle, oocyst residuum, or polar granule and contain eight spindle-shaped sporozoites and no sporocysts. Sporulation is completed within the gall bladder lumen. Comparison with other species of the genus found in reptiles indicates that it is a new species.  相似文献   
196.
ABSTRACT. Four isosporan species are described from the small tree finch, Camarhynchus parvulus from Isabela Island on the Galapagos Archipelago. Isospora exigua n. sp. oocysts subspheroidal, one-layered, smooth, yellow-brown color, 20.4 × 20.1 (20-23 × 18-23) μm, with no micropyle, residuum, or polar body. Sporocysts ovoidal, 14 × 9.5 (13-15 × 8-10) μm, with small Stieda and substieda bodies and irregular-shaped residuum. Isospora rotunda n. sp. oocysts subspheroidal, single-layered, smooth, yellow-brown wall with large polar body and no micropyle or residuum, 20.9 × 20.8 (20-24 × 19-23) μm. Sporocysts ovoidal, 15 × 9.7 (13-16 × 9-10) μm with knob-like Stieda bodies, prominent substieda bodies and round residuum. Isospora fragmenta n. sp. oocysts subspheroidal with no micropyle or residuum but with many splinter-like polar granules and a smooth, colorless, single-layered wall, 25.3 × 24.2 (24-27 × 23-25) μm. Sporocysts piriform 15.4 × 11.5 (14-17 × 11-12) μm with knob-like Stieda bodies, prominent substieda bodies, and irregular-shaped residuum. Isospora temeraria n. sp. oocysts ellipsoidal with one polar body, no micropyle or residuum, and wall of a single layer, smooth, yellow-brown color, 25.4 × 21.1 (21-30 × 17-23) μm. Sporocysts piriform, 15 × 10 (14-15 × 9-11) μm with knob-like Stieda bodies, prominent substieda bodies, and a round residuum. One woodpecker finch, Cactospiza pallida, was found to be infected with I. exigua, and a warbler finch, Certhidea olivacea was infected with I. fragmenta.  相似文献   
197.
An Audit of Cervical Cancer Deaths In Nottingham   总被引:1,自引:0,他引:1  
Death certificates were reviewed and 57 women were identified whose primary cause of death was cervical cancer. Their cervical smear records were reviewed from laboratory files. Only nine had participated in the cervical cancer screening programme before the diagnosis of cervical cancer was made. One woman had an abnormal smear as a result of cervical screening but failed to attend for follow-up.
The problem of false negative smears is also addressed and the value of review of negative smears for the purposes of cytology audit is emphasized.  相似文献   
198.
Measuring the Canopy Net Photosynthesis of Glasshouse Crops   总被引:3,自引:0,他引:3  
A null balance method is described for measuring net photosynthesisof mature canopies of cucumber and other protected crops overperiods of 10 min in a single-span glasshouse (c. 9m x 18m inarea). Accuracy of control of the CO2 concentration in the greenhouseatmosphere is within ±10 vpm of the normal ambient level(c. 350 vpm). The amounts of CO2 used in canopy net photosynthesisare measured with linear mass flowmeters accurate to within±0.80g. The total errors incurred in measuring canopynet photosynthesis at an ambient CO2 level are estimated tobe of the order of ± 1·2% in bright light (350W m–2, PAR)and ±3·6% in dull light (100W m–2, PAR). Measurements of the rates of net photosynthesis of a maturecanopy of a cucumber crop were made at near-ambient CO2 concentrationsover a range (0–350 W m–2) of natural light fluxdensities. A model of light absorption and photosynthesis applicableto row crops was used to obtain a net photosynthesis versuslight response curve for the cucumber crop. At a light fluxdensity of 350 W m–2 the fitted value of canopy net photosynthesiswas 2.65 mg CO2 m–2s–1 (equivalent to over 95 kgCO2 ha–1h–1). The results are discussed in relationto the need for CO2 supplements to avoid depletion in both ventilatedand unventilated glasshouses during late spring and summer. Key words: Glasshouse crops, cucumber, measurement, canopy photosynthesis, light, CO2  相似文献   
199.
The Ontogeny of Mammalian Mastication   总被引:2,自引:1,他引:1  
Movements of the oral apparatus begin during the fetal periodand develop in a consistent order. Jaw openingappears first,followed by active jaw closure and tongue movements, lip movements,sucking, and finally masticatory movements. The later developingmovements appear prenatally in precocious mammals such as guineapigs and sheep, but are postnatal in altricial mammals suchas rats, hamsters and rabbits. The orderly development of oralbehavior is probably related to the progressive maturation ofthe nervous system and neuromuscular connections. Most newbornmammals feed exclusively bysuckling, a combination of the tongueworking against the nipple and negative pressure at the backof the oral cavity. Thetransition from suckling to masticationis gradual and involves considerable learning. In at least onespecies, the domestic pig, infant animals chew using a somewhatdifferent muscular contraction pattern from that of adults.Age changes in muscle action lines are the most likely explanationfor this difference. After being established in infancy, theprocess of mastication undergoes only minor changes in rateand relative muscle activity during the juvenile period. Throughoutontogeny there is a reciprocal relation between morphology andbehavior. While masticatory performance depends on structureat any given stage, it also has profound effects on furthermusculoskeletal growth and differentiation.  相似文献   
200.
Human remains from two cemeteries at Kulubnarti in Sudanese Nubia present an ideal opportunity to assess the biological impact of political and economic change. Remains from the early cemetery come from Nubia's medieval period, characterized by political unification and important achievements in art and architecture. Remains from the second cemetery come from the later emergent feudal age, characterized by regional isolation and return to a subsistence economy. Patterns of mortality, growth, development, nutrition, and disease revealed by the remains converge on one conclusion: the transformation from the medieval to the feudal age at Kulubnarti witnessed an improvement in human health and survival.  相似文献   
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