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61.
Michelle L. Taylor Nina Wedell David J. Hosken 《Behavioral ecology and sociobiology》2008,62(5):721-728
There is a current debate over the net fitness consequences of sexual selection. Do preferred males increase female fitness or are these males manipulating females for their own benefit? The evidence is mixed. Some studies find that mating with attractive males increases female fitness components, while others show that preferred males decrease measures of female fitness. In this study, we examined some of the fitness consequences of pre-copulatory sexual selection in Drosophila simulans. Virgin females were either paired with one male and given an opportunity for one copulation or were exposed simultaneously to two males. This allowed us to compare female preference (copulation latency) and fitness (longevity, lifetime productivity and rate of offspring production) both with and without the influence of male–male competition. When females had access to a single male, neither female longevity, productivity, nor short-term rate of productivity were associated with female preference, and although females mated more quickly with larger males, male size was also not associated with any female fitness measure. Inclusion of male–male competition showed that female longevity was negatively affected by preference, while productivity and rate of productivity was unaffected. This latter experiment also indicated that females preferred larger males, but again, male size was not associated with female fitness. These results indicate that females may not benefit from mating with preferred males, but they may incur survival costs. 相似文献
62.
采用均匀设计的实验方法,研究了2种核桃果皮炭粉(提取水溶性混合物和未提取水溶性混合物的核桃皮炭粉)对Cr、Cu和Cd等重金属离子的吸附最优条件以及对3种离子吸附的影响因素。结果表明,核桃皮炭粉对Cr(Ⅵ)、Cd2+和Cu2+的吸附最优条件为:pH=4,温度为60℃,浓度为150μg/mL,吸附剂用量为2.4 g,时间为120 min;pH=4.5,温度为30℃,浓度为180μg/mL,吸附剂用量为5.4 g,时间为60 min;pH=5,温度为80℃,浓度为210μg/mL,吸附剂用量为0.4 g,时间为100 min;pH和Cr(Ⅵ)浓度增大,不利于2种吸附剂对Cr(Ⅵ)的吸附;pH和温度增大,不利于2种吸附剂对Cu2+的吸附;温度和吸附剂用量增加,有利于2种吸附剂对Cd2+的吸附。未提取水溶性混合物比提取水溶性混合物的核桃果皮炭粉对3种金属的吸附显著。2种吸附剂的吸附率均表现为Cr>Cd>Cu。 相似文献
63.
The aim of the work was to study the influence of the water taken from one of the most polluted parts of the Peter the Great
Bay (the Japan Sea), the Nakhodka Bay, on the growth and chlorophyll a concentration in the cells of microalga P. tricornutum Bohlin (Bacillariophyta). The estimation of the dynamics of cell number growth and chlorophyll a concentration in the cells
of microalga grown in the water from the Nakhodka Bay was made. At the same time, in 2007–2008, the main hydrochemical parameters,
such as water salinity, dissolved oxygen concentration, BOD5, organic and mineral phosphates concentration, anionic surfactants, and total petroleum hydrocarbons, were determined. It
is shown that in July 2007, when most hydrochemical parameters were lower than the maximum permissible level, the culture
growth and chlorophyll a contents in the cells did not differ from the control for certain. In other seasons these indices
differed greatly from the control. The positive correlation between the concentration of dissolved oxygen, phosphates, petroleum
hydrocarbons, and the number of microalga cells, grown in the water from the Nakhodka Bay, was shown. 相似文献
64.
65.
Katinka Weller Gabriëla G. Edel Eric A. P. Steegers Irwin K. M. Reiss Philip L. J. DeKoninck Robbert J. Rottier Alex J. Eggink Nina C. J. Peters 《黑龙江环境通报》2023,43(10):1296-1309
Pathophysiological studies have shown that pulmonary vascular development is impaired in fetuses with a congenital diaphragmatic hernia (CDH), leading to a simplified vascular tree and increased vascular resistance. Multiple studies have described prenatal ultrasound parameters for the assessment of the pulmonary vasculature, but none of these parameters are used in daily clinical practice. We provide a comprehensive review of the literature published between January 1990 and February 2022 describing these parameters, and aim to explain the clinical relevance of these parameters from what is known from pathophysiological studies. Prenatal detection of a smaller diameter of the contralateral (i.e. contralateral to the diaphragmatic defect) first branch of the pulmonary artery (PA), higher pulsatility indices (PI), higher peak early diastolic reverse flow values, and a lower vascularization index seem of added value for the prediction of survival and, to a lesser extent, morbidity. Integration within the routine evaluation is complicated by the lack of uniformity of the methods used. To address the main components of the pathophysiological changes, we recommend future prenatal studies in CDH with a focus on PI values, PA diameters and pulmonary vascular branching. 相似文献
66.
Maija Lintula Nina Nevala-Puranen Veikko Louhevaara 《International journal of occupational safety and ergonomics》2013,19(1):103-116
The effects of Ergorest® arm supports on wrist angles and musculoskeletal strain in the neck-shoulder-arm region and electrical activity in the shoulder and arm muscles were studied during typing or the use of the mouse in work with a visual display unit (VDU). Twenty-one women were randomized into 3 groups (1 arm support, 2 arm supports, and control). Measurements were carried out before and after the 6-week intervention. The wrist extension of the mouse hand, the muscle activity of the trapezius muscle, and the subjective discomfort ratings indicated that 2 arm supports were better than 1 in work with a mouse. The Ergorest® arm support alleviates muscle and joint strain in VDU work when used for both arms. 相似文献
67.
The risk of B phytotoxicity due to high levels of B in irrigation water can be avoided by removing B from the water, before its use, through adsorption on certain adsorbents, such as magnesia (industrial MgO), if the latter can be proven to be an effective and easy to handle means for B removal. In addition, if such a material is applied as a fertilizer after its use and the adsorbed B is easily released into the soil solution, B phytotoxicity could constitute a potential hazard. The objectives of this work were to: (a) establish the optimum working conditions (equilibration time, solution to adsorbent ratio, and particle size of the adsorbent) for B adsorption, (b) assess the magnitude of B adsorption by magnesia, both in capacity and intensity terms, as well as the influence of temperature, (c) study B desorbability from magnesia, spiked with B at two rates, 5 and 0.5 mg g(-1), and (d) compare the results from b and c to those obtained using reagent grade MgO. The results showed that the time to achieve equilibrium depended on the B concentration of the external solution and ranged from 6 h (for B = 10 mg L(-1)) to 48 h (for B >/= 50 mg L(-1)). The percentage of B adsorbed decreased as the volume of external solution to adsorbent increased and a working ratio of 50:1 was selected. For magnesia, B adsorption was particle size dependent with the smallest fraction (<0.1 mm) sorbing more B than the other three fractions studied (0.1-1.0, 1.1-2.0, 2.1-4.0 mm). Boron adsorption was conducted under strongly alkaline pH (10.3 +/- 0.2 and 10.4 +/- 0.1 for the reagent and magnesia, respectively) and increased with temperature. Both adsorbents exhibited a high B adsorption capacity (Langmuir maximum values were 5.85 +/- 0.39 and 4.45 +/- 1.31 mg B g(-1) for the reagent and magnesia, respectively) comparable to other metal oxides. However, the reagent grade MgO seemed to be superior to magnesia in terms of capacity and strength of B retention. This superiority of the reagent was attributed to its greater surface area (34.7 compared with 5.8 m(2) g(-1) for magnesia) and to its conversion to Mg(OH)(2) during the adsorption process, whereas magnesia remained unaltered, as was evident from X-ray diffractograms. Based on this data, magnesia seems to be an effective means for removing excess B from irrigation water, particularly if a material of fine particle size is used. Boron desorbability after 240 h of desorption time was more pronounced for magnesia reaching up to 55 and 60% of the amount of B added, at the spiked rates of 5 and 0.5 mg g(-1), respectively. Although these figures indicate that approximately half of the amount of B added remained adsorbed, they cannot be easily extrapolated to field conditions, and if B-laden magnesia is applied to soils, the possibility of B phytotoxicity cannot be excluded. 相似文献
68.
Sialic acid storage disorders, Salla disease (SD) and a severe infantile form of disease (ISSD), are recessively inherited allelic lysosomal storage disorders due to impaired egress of free sialic acid from lysosomes. Fourteen pregnancies at risk of adult-type free sialic acid storage disease, SD, were monitored by sialic acid assays, genetic linkage or mutation detection analyses using chorionic villus samples. Three affected and 12 unaffected fetuses were identified. The first studies were based on the sialic acid assays alone, but the location of the gene enabled the use of genetic linkage analysis and, more recently, the identification of the SLC17A5 gene and disease-causing mutations added yet another possibility for prenatal studies. A missense mutation 115C→T (R39C) is present in 95% of all Finnish SD alleles, providing an easy and reliable means of diagnostic studies. Both molecular and biochemical (sialic acid assay) studies can be used for prenatal diagnosis of free sialic acid storage diseases. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
69.
Vera A. Matrosova Ilya A. Volodin Elena V. Volodina Nina A. Vasilieva 《Die Naturwissenschaften》2010,97(8):707-715
The questions of individuality and stability of cues to identity in vocal signals are of considerable importance from theoretical
and conservation perspectives. While individuality in alarm calls has been reported for many sciurids, it is not well-documented
that the vocal identity encoded in the alarm calls is stable between different encounters with predators. Previous studies
of two obligate hibernating rodents, speckled ground squirrels Spermophilus suslicus, and yellow ground squirrels Spermophilus fulvus demonstrated that, after hibernation, most individuals could not be identified reliably by their alarm calls. Moreover, in
most speckled ground squirrels, individual patterns of alarm calls changed progressively over as little as 2 weeks. However,
these previous data have been obtained using the collection of alarm calls from trapped animals. Here, we examined ten free-ranging
dye-marked yellow ground squirrels to determine whether their alarm calls retain the cues to individuality between two encounters
of surrogate predators (humans), separated on average by 3 days. Discriminant function analysis showed that the alarm calls
of individual yellow ground squirrels were very similar within a recording session, providing very high individual distinctiveness.
However, in six of the ten animals, the alarm calls were unstable between recording sessions. Also, we examined ten dye-marked
individuals for consistency of acoustic characteristics of their alarm calls between the encounters of humans, differing in
techniques of call collection, from free-ranging vs trapped animals. We found differences only in two variables, both related
to sound degradation in the environment. Data are discussed in relation to hypotheses explaining the adaptive utility of acoustic
individuality in alarm calls. 相似文献
70.
Vesna Zupanc Martina ŠturmSonja Lojen Nina Marši?-KacjanJoseph Adu-Gyamfi Branka Bra?i?-?eleznikJanko Urbanc Marina Pintar 《Agriculture, ecosystems & environment》2011,144(1):167-174
In the search for new technologies that would ensure optimum yield and environmental sustainability, various irrigation, nitrogen and cropping system management strategies for the production of vegetables with a shorter growing period were assessed at a benchmark site in Slovenia for the years 2006 and 2007. In the studied years four irrigation and fertilization treatments were applied: (1) 50% drip irrigation of plants water requirements ETcrop and the farmer's practice of fertilisation (broadcasting), (2) fertilisation and 100% drip irrigation (fertigation), (3) the farmer's practice of irrigation (sprinkler irrigation using water stored in plastic tanks) and fertilisation, and (4) control (the farmer's practice of irrigation but no fertilisation). An equivalent of 80, 80 and 200 kg ha−1 of nitrogen (N), 50, 50 and 80 kg ha−1 of phosphorous (P) and 120, 120 and 300 kg ha−1 of potassium (K) was added for iceberg lettuce, endive and cabbage, respectively. Nitrogen (N) labelled fertilizer (15N) was applied to trace the movement of the applied N fertiliser. The tested irrigation and fertilisation techniques for the production of vegetables with a shorter growing period in the Slovenian climate showed that environmentally sustainable practices (split application of nutrients compared to broadcast incorporating fertilisation) should be a practice of choice in water protection zones. The results confirm that fertigation and improved irrigation scheduling can be an effective way of minimizing nitrate leaching, and should be considered for vegetable production in or close to groundwater protection zones. 相似文献