Further investigation of lead exposure as a potential threatening process for a scavenging marsupial species     

DJ Hutchinson  EM Jones  JM Pay  JR Clarke  MT Lohr  JO Hampton 《Australian veterinary journal》2023,101(8):313-319

There is a growing recognition of the harmful effects of lead exposure on avian and mammalian scavengers. This can lead to both lethal and non-lethal effects which may negatively impact wildlife populations. Our objective was to assess medium-term lead exposure in wild Tasmanian devils (Sarcophilus harrisii). Frozen liver samples (n = 41), opportunistically collected in 2017–2022, were analysed using inductively coupled plasma mass spectrometry (ICP-MS) to determine liver lead concentrations. These results were then used to calculate the proportion of animals with elevated lead levels (>5 mg/kg dry weight) and examine the role of explanatory variables that may have influenced the results. The majority of samples analysed were from the south-east corner of Tasmania, within 50 km of Hobart. No Tasmanian devil samples were found to have elevated lead levels. The median liver lead concentration was 0.17 mg/kg (range 0.05–1.32 mg/kg). Female devils were found to have significantly higher liver lead concentrations than males (P = 0.013), which was likely related to lactation, but other variables (age, location, body mass) were not significant. These results suggest that wild Tasmanian devil populations currently show minimal medium-term evidence of exposure to lead pollution, although samples were concentrated in peri-urban areas. The results provide a baseline level which can be used to assess the impact of any future changes in lead use in Tasmania. Furthermore, these data can be used as a comparison for lead exposure studies in other mammalian scavengers, including other carnivorous marsupial species.  相似文献   

National participation levels in the 2017–2018 Australian thoroughbred racing season     

ML Flash  K Shrestha  MA Stevenson  JR Gilkerson 《Australian veterinary journal》2023,101(7):265-274

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Distribution Pattern(s) of Sperm Protein at 22 kDa (SP22) on Fresh,Cooled and Frozen/Thawed Equine Spermatozoa and Expression of SP22 in Tissues from the Testes and Epididymides of Normal Stallions          下载免费PDF全文

LMJ Miller  EM Woodward  JR Campos  EL Squires  MHT Troedsson 《Reproduction in domestic animals》2015,50(2):275-282

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Extreme ultraviolet satellites open new view of the sky     

Goldsmith D 《Science (New York, N.Y.)》1995,268(5208):202-203

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Early events in vision     

Goldsmith TH 《Science (New York, N.Y.)》1979,203(4381):641-642

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The Seismic Structure of the Sun     

DO Gough  AG Kosovichev  J Toomre  E Anderson  HM Antia  S Basu  B Chaboyer  SM Chitre  J Christensen-Dalsgaard  WA Dziembowski  A Eff-Darwich  JR Elliott  PM Giles  PR Goode  JA Guzik  JW Harvey  F Hill  JW Leibacher  MJPFG Monteiro  O Richard  T Sekii  H Shibahashi  M Takata  MJ Thompson  S Vauclair  SV Vorontsov 《Science (New York, N.Y.)》1996,272(5266):1296-1300

Global Oscillation Network Group data reveal that the internal structure of the sun can be well represented by a calibrated standard model. However, immediately beneath the convection zone and at the edge of the energy-generating core, the sound-speed variation is somewhat smoother in the sun than it is in the model. This could be a consequence of chemical inhomogeneity that is too severe in the model, perhaps owing to inaccurate modeling of gravitational settling or to neglected macroscopic motion that may be present in the sun. Accurate knowledge of the sun's structure enables inferences to be made about the physics that controls the sun; for example, through the opacity, the equation of state, or wave motion. Those inferences can then be used elsewhere in astrophysics.  相似文献   

Use of Sieved Compost Plus Hydrogel for Solid Matrix Priming of Carrot Seeds     

M.W. Olszewski  R.S. Goldsmith  E.K. Guthrie  C.A. Young 《Compost science & utilization》2013,21(1):5-10

In this study we report the water release curve of a compost-based carrier for solid matrix priming and its effects on carrot seed germination. ‘Danvers Half Long’ and ‘Nantes Scarlet’ carrot (Daucus carota) seeds were primed for 7 d at 15°C in a carrier consisting of 5:1:5.7 sieved compost: hydrogel:distilled water (based on weight) equaling a water potential of ?1.0 MPa. Seeds were blended with carrier at 1:10, 1:20, 1:30, or 1:40 (based on weight) and compost priming was compared with a polyethylene glycol (PEG) priming procedure. Germination testing at 20-30°C (16-8 h) in darkness indicated that all compost priming treatments hastened seed germination more than PEG priming. Compost priming at 1:30 increased final germination percentage (FGP) for ‘Nantes Scarlet’ (FGP = 85%) compared to PEG primed (FGP = 72%) seeds but ‘Danvers Half Long’ FGP was similar for all treatments. For both cultivars, seeds that were compost primed had reduced G (days to 10% FGP) and G (days to 50% FGP) compared to PEG primed or nonprimed seed. For ‘Danvers Half Long’ carrot seeds, priming ratios of 1:30 reduced G values more effectively than all other treatments. For ‘Nantes Scarlet’ carrot seeds, G₁₀ and G₅₀ values were reduced similarly at all seed-to-carrier ratios. Compost primed seeds could be dried and stored for 35 d at 3 or 20-30°C (16-8 h) for ‘Danvers Half Long’ and for 35 d at 3°C for ‘Nantes Scarlet’ with no loss in priming benefit. We conclude that solid matrix priming with a compost based carrier is a satisfactory alternative to PEG priming to improve germination of carrot seed.  相似文献   

Responses in growth rate of larval northern anchovy (Engraulis mordax) to anomalous upwelling in the northern California Current     

DAVID M. CHECKLEY JR  MARISA N.C. LITZ  RICHARD D. BRODEUR  WILLIAM T. PETERSON 《Fisheries Oceanography》2012,21(6):393-404

We examined variability in growth rate during the larval stage of northern anchovy (Engraulis mordax) in response to physical and biological environmental factors in 2005 and 2006. The onset of spring upwelling was anomalously delayed by 2–3 months until mid‐July in 2005; in contrast, spring upwelling in 2006 began as a normal year in the northern California Current. Larval and early juvenile E. mordax were collected in August, September, and October off the coast of Oregon and Washington. Hatch dates ranged from May to September, with peaks in June and August in 2005 and a peak in July in 2006, based on the number of otolith daily increments. Back‐calculated body length‐at‐age in the June 2005 hatch cohort was significantly smaller than in the August 2005 cohort, which had comparable growth to the July 2006 cohort. Standardized otolith daily increment widths as a proxy for seasonal variability in somatic growth rates in 2005 were negative until late July and then changed to positive with intensification of upwelling. The standardized increment width was a positive function of biomass of chlorophyll a concentration, and neritic cold‐water and oceanic subarctic copepod species sampled biweekly off Newport, Oregon. Our results suggest that delayed upwelling in 2005 resulted in low food availability and, consequently, reduced E. mordax larval growth rate in early summer, but once upwelling began in July, high food availability enhanced larval growth rate to that typical of a normal upwelling year (e.g., 2006) in the northern California Current.  相似文献   

Estimating the outcrossing rate of Cyperus difformis using resistance to ALS-inhibiting herbicides and molecular markers     

A MEROTTO JR  M JASIENIUK†  & A J FISCHER† 《Weed Research》2009,49(1):29-36

Cyperus difformis (smallflower umbrella sedge) is an economically important weed of rice in California where its control has recently been complicated by the evolution of herbicide resistance. Knowledge of the mating system of this weed is needed to elucidate the dynamics of resistance evolution and to design mitigation strategies that delay its occurrence. The aim of this study was to estimate the outcrossing rate of C. difformis using molecular and phenotypic markers. Outcrossing rates were estimated in natural field populations using sequence-related amplified polymorphism (SRAP) molecular markers and in glasshouse and field experiments using resistance to the acetolactate synthase-inhibiting herbicide bensulfuron-methyl as a phenotypic marker. Using SRAP markers, the multilocus ( t _m) and average single-locus ( t _s) outcrossing rates varied from 0.014 to 0.025 and from 0.008 to 0.012, respectively, among natural weed populations in rice fields. Using resistance to bensulfuron-methyl as a genetic marker, the average C. difformis outcrossing rate estimated was 0.009 in the glasshouse and 0.0084 in the field. These results indicate that C. difformis is a highly self-fertilising species. Therefore, the primary mechanism by which genes for herbicide resistance can be transferred among C. difformis populations in different rice fields is probably seed dispersal. Weed management should emphasise prevention of seed production and dispersal to preclude the further spread and evolution of resistance in C. difformis .  相似文献   

Transplacental Transfer of Iron in the Water Buffalo (Bubalus bubalis): Uteroferrin and Erythrophagocytosis     

FTV Pereira  FC Braga  KC Burioli  JR Kfoury Jr  LJ Oliveira  PC Papa  AF Carvalho  CE Ambrósio  FW Bazer  MA Miglino 《Reproduction in domestic animals》2010,45(5):907-914

The objectives of this investigation were to understand transplacental transport of iron by secreted uteroferrin (UF) and haemophagous areas of water buffalo placenta and clarify the role(s) of blood extravasation at the placental‐maternal interface. Placentomes and interplacentomal region of 51 placentae at various stages of gestation were fixed, processed for light and transmission electron microscopy, histochemistry and immunohistochemistry. Haemophagous areas were present in placentomes collected between 4 and 10 months of pregnancy. Perl’s reaction for ferric iron was negative in placentomes, but positive in endometrial glands. Positive staining for UF indicated areas in which it was being taken up by phagocytosis and/or fluid phase pinocytosis in areolae of the interplacentomal mesenchyme, with little staining in endometrial stroma. Imunohistochemistry detected UF in trophectoderm of haemophagous regions of placentomes and in other parts of the foetal villous tree, but the strongest immunostaining was in the epithelial cells and lumen of uterine glands. Ultrastructural analyses indicated that erythrophagocytosis was occurring and that erythrocytes were present inside cells of the chorion that also contained endocytic vesicles and caveolae. Results of this study indicate that both the haemophagous areas of placentomes and the areolae at the interface between chorion and endometrial glands are important sites for iron transfer from mother to foetal‐placental tissues in buffalo throughout pregnancy.  相似文献