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411.
This paper reports a field investigation of interactions between juveniles and their mothers in the Australian sleepy lizard,
Tiliqua rugosa. In their first spring season, juvenile lizards maintain home ranges largely within the home range of their mother. Juvenile
home ranges are significantly smaller than those of adult males and females, and juveniles move significantly less often and
significantly shorter distances than adults. While siblings were never found together in the spring, they showed a significant
tendency to be closer to each other than if they were randomly located in their home ranges. Juveniles and mothers were never
found together, nor was there any evidence for any positive (or negative) spatial association. Nevertheless, the extended
tolerance of home range overlap represents a greater degree of mother-offspring association than has been previously reported
for other lizards. Despite this, the level of parental care can only be described as minimal.
Received: 20 June 1997 / Accepted after revision: 29 December 1997 相似文献
412.
In this work the authors describe the main characteristics of the velocity field of hydraulic jumps in a very large channel
where lateral shockwaves occur. Experiments were carried out at the Coastal Engineering Laboratory of the Water Engineering
and Chemistry Department of the Technical University of Bari (Italy). Extensive flow velocity measurements were investigated
in order to have a clearer understanding of both hydraulic jump development and lateral shockwave formation in a very large
channel. Eight experiments were performed in a 4m wide rectangular channel; the experiments differed in the inlet Froude number
F
0 and the jump type. Seven tests were carried out with undular jumps and one with a roller jump. The flow velocity and the
flow free surface measurements were taken using a two-dimensional Acoustic Doppler Velocimeter (ADV) and an ultrasonic profiler,
respectively. The experimental results can be summarized as follow: (i) the formation of well developed lateral shockwaves
similar to those of oblique jumps were observed; (ii) the comparison of the experimental and theoretical data shows that the
classic shockwave theory is sufficiently confirmed in the analyzed range of Reynolds number, taking into account the experimental
errors and the difference between the theoretical and experimental assumptions; (iii) the transversal flow velocity profiles
in the recirculating zone show a good agreement with the numerical simulations presented in literature in the case of a separated
turbulent boundary layer over a flat plate. This conclusion enables us to confirm the hypothesis that the lateral shockwaves
in the channel are the result of a boundary layer which, as observed, forms on the channel sidewalls. 相似文献
413.
414.
Spinal deformities are seen in fishes. Deformities in the family Syngnathidae is rarely reported. Spine curvatures in natural population of pipefish, Syngnathus abaster are reported from the Tunis North Lake. The species is euryhaline and occurs along the Mediterranean coasts. Four hundred specimens of S. abaster were collected from January 2006 to December 2007 from the Tunis North Lake. Two specimens with skeletal abnormalities were described for the first time. X-rays radiographies revealed several vertebral deformities for each deformed specimen, especially at five curvation places of the caudal part. Several factors are believed to be the cause of spinal deformities of S. abaster in the Tunis North Lake, such as environmental disturbances, parasitism infection and nutritional factors. 相似文献
415.
Kefford BJ Marchant R Schäfer RB Metzeling L Dunlop JE Choy SC Goonan P 《Environmental pollution (Barking, Essex : 1987)》2011,159(1):302-310
The risk of chemicals for ecological communities is often forecast with species sensitivity distributions (SSDs) which are used to predict the concentration which will protect p% of species (PCp value). However, at the PCp value, species richness in nature would not necessary be p% less than at uncontaminated sites. The definition of species richness inherent to SSDs (contaminant category richness) contrasts with species richness typically measured in most field studies (point richness). We determine, for salinity in eastern Australia, whether these definitions of stream macroinvertebrate species richness are commensurable. There were strong relationships (r2 ≥ 0.87) between mean point species, family and Ephemeroptera, Trichoptera and Plecoptera species richness and their respective contamination category richness. Despite differences in the definition of richness used by SSDs and field biomonitoring, their results in terms of relative species loss from salinity in south-east Australia are similar. We conclude that in our system both definitions are commensurable. 相似文献
416.
Tkacz B Moody B Castillo JV Fenn ME 《Environmental pollution (Barking, Essex : 1987)》2008,155(3):409-425
Some of the greatest forest health impacts in North America are caused by invasive forest insects and pathogens (e.g., emerald ash borer and sudden oak death in the US), by severe outbreaks of native pests (e.g., mountain pine beetle in Canada), and fires exacerbated by changing climate. Ozone and N and S pollutants continue to impact the health of forests in several regions of North America. Long-term monitoring of forest health indicators has facilitated the assessment of forest health and sustainability in North America. By linking a nationwide network of forest health plots with the more extensive forest inventory, forest health experts in the US have evaluated current trends for major forest health indicators and developed assessments of future risks. Canada and Mexico currently lack nationwide networks of forest health plots. Development and expansion of these networks is critical to effective assessment of future forest health impacts. 相似文献
417.
Data concerning the concentration of dioxins (PCDD/PCDFs), polychlorinated biphenyls (PCBs), metals, metalloids, pesticides and antimicrobials residues are reported for the edible portion of Australian wild and farmed southern bluefin tuna (Thunnus maccoyii). In 2004 wild caught (n=5) and farmed (n=26) southern bluefin tuna (SBT) were collected. The mean concentration of total mercury on a fresh weight (fw) basis was 0.34 mg/kg in wild SBT and 0.31 mg/kg in farmed SBT. Concentrations of dioxins (PCDD/PCDFs) and polychlorinated biphenyls (PCBs) found in wild SBT were extremely low. The mean concentration (fw) of the sum of PCDD/PCDFs and the dioxin-like PCBs was 0.27 pg TEQ/g in wild SBT and 0.61 pg TEQ/g in farmed SBT. Mean PCB total concentration (fw basis) was 0.47 ng/g in wild SBT and 6.60 ng/g in farmed SBT. No detectable residues of any pesticide or antimicrobial compounds were found. All residues detected were within regulatory limits set by the Japanese Competent Authority, the Ministry of Health, Labour and Welfare (MHLW) and the Australian Competent Authority, Food Standards Australia New Zealand (FSANZ). The need for harmonisation of international product integrity procedures for bluefin tunas in international trade is highlighted. 相似文献
418.
围场县农田典型药物和个人护理品污染特征与生态风险预评价 总被引:1,自引:0,他引:1
利用超声萃取-固相萃取-高效液相色谱/串联质谱(LC-MS/MS)技术,对围场县全县农田中5个大类(磺胺类、四环素类、氟喹诺酮类、大环内酯类以及其他类)25种典型药物和个人护理品(PPCPs)的污染水平进行了调查,并采用风险熵法对其进行生态风险预评价。结果表明:有23种目标PPCPs被检出,不同目标物检出率差异显著,检出含量范围为0.38~6.50μg·kg-1,单种污染物最高检出浓度为101.9μg·kg-1(磺胺甲恶唑)。以目标物划分,分别有7种和5种被检出物质达到生态高风险和中等风险水平;以采样区域划分,41个土壤点位中分别有17个和12个达到生态高风险和中等风险水平。畜用PPCPs是围场农田中PPCPs污染物的主要来源,兽药滥用、粪便自然堆沤等传统农耕模式有造成农田土壤中PPCPs累积的趋势,因此需严控PPCPs污染源头,并推进畜禽粪便安全的资源化利用,以减缓农田土壤中由于PPCPs污染带来的潜在生态风险,保障围场地区生态环境功能、农田环境质量以及农产品安全品质。 相似文献
419.
Nasri Emna Machreki Monia Beltifa Asma Aroui Sonia Ghorbel Asma Saad Amina Feriani Anouar Borgi Mohamed Ali Ghazouani Lakhdar Sire Olivier Balcázar José Luis Mansour Hedi Ben 《Environmental science and pollution research international》2017,24(25):20422-20428
Environmental Science and Pollution Research - Hospital wastewaters contain large amounts of pharmaceutical residues, which may eventually be discharged into the aquatic environment through... 相似文献
420.