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1.
Chromosome studies were performed on a series of 177 couples referred for genetic counseling following two or more spontaneous abortions to clarify the relationship between karyotype and fertility in males and females and to provide risk figures for genetic counseling. The results of these investigations, when combined with those in the literature, suggest that 2-3% of individuals in couples experiencing early fetal losses carry a balanced translocation and that this is not markedly influenced by the number of losses greater than two. Females are more likely than males to be the carrier, reflecting the fact that structural abnormalities of the chromosomes that are compatible with fertility in the female may be associated with sterility in the male. Karyotyping should be performed on both members of a couple following two spontaneous abortions and the products of conception should be studied whenever possible to begin to determine the biological basis of the association between parental rearrangement and fetal loss.  相似文献   

2.
McLester et al. (2003) proposed a practical protocol to determine optimal recovery times between resistance training workouts. For this protocol to be useful, it must be stable. The purpose of this study was to investigate the stability of that protocol. College-aged resistance trained men (n = 10) performed 3 sets to volitional failure using a 10-repetition maximum load for 6 exercises. Recovery was evaluated on 4 occasions by the number of repetitions performed for each individual exercise after recovery periods of 48, 72, 96, and 120 hours in counterbalanced order. To evaluate stability, this procedure was performed twice. The number of repetitions after each recovery interval were compared with initial baseline performances. A priori, adequate stability was defined as 70% of the participants achieving similar recovery duration on both trials. Pooled repetitions over all 6 exercises indicated that 80% of participants returned to baseline strength levels after the same recovery duration for both trials. However, when individual muscle group repetition performance was evaluated, stability varied from 20 to 70%. Variability in rest, nutrition, prior activity, and other factors probably induced instability in individual strength measures, but not sufficiently to influence the aggregate results. Some muscle groups may have greater sensitivity to variations in ecological factors such as these. We believe that the tested protocol may be useful in establishing recovery times for multimuscle group workouts, but not stable enough to be useful in establishing recovery times for individual muscle groups.  相似文献   

3.
Problems in the interpretation of 14C-primary production estimates have resulted from our belief that all carbon compounds are created equal and few attempts have been made to include nighttime 14C-losses. The energetic costs of protein synthesis are high and once formed protein is not simply used as another form of energy but is conserved along food chains. A portion of the carbohydrate fraction is used to drive night protein synthesis and some, the so called colloidal dissolved organic carbon which represents a portion of the extracellular production, simply aggregates and settles out.Areal productivity measured over 24 hours was monitored in Lake Ontario and compared with losses through sedimentation and zooplankton grazing. The balance was related to NET changes in particulate organic carbon (POC) concentration. Prior to stratification, sedimentation accounted for most of the carbon losses from the trophogenic zone but during stratification, zooplankton grazing was coupled with plankton growth (determined as protein synthesis per unit particulate protein). This observation, supported by very low phosphorus sedimentation rates suggests that phosphorus is effectively recycled within the epilimnion.  相似文献   

4.
This study concerns the identification and correction of deficiencies in methods used to measure inactivation rates of enteric viruses seeded into environmental waters. It was found that viable microorganisms in an environmental water sample increased greatly after addition of small amounts of nutrients normally present in the unpurified seed virus preparation. This burst of microbial growth was not observed after seeding the water with purified virus. The use of radioactively labeled poliovirus revealed that high percentages of virus particles, sometimes greater than 99%, were lost through adherence to containers, especially in less turbid waters. This effect was partially overcome by the use of polypropylene containers and by the absence of movement during incubation. Adherence to containers clearly demonstrated the need for labeled viruses to monitor losses in this type of study. Loss of viral infectivity in samples found to occur during freezing was avoided by addition of broth. Finally, microbial contamination of the cell cultures during infectivity assays was overcome by the use of gentamicin and increased concentrations of penicillin, streptomycin, and amphotericin B.  相似文献   

5.
This study concerns the identification and correction of deficiencies in methods used to measure inactivation rates of enteric viruses seeded into environmental waters. It was found that viable microorganisms in an environmental water sample increased greatly after addition of small amounts of nutrients normally present in the unpurified seed virus preparation. This burst of microbial growth was not observed after seeding the water with purified virus. The use of radioactively labeled poliovirus revealed that high percentages of virus particles, sometimes greater than 99%, were lost through adherence to containers, especially in less turbid waters. This effect was partially overcome by the use of polypropylene containers and by the absence of movement during incubation. Adherence to containers clearly demonstrated the need for labeled viruses to monitor losses in this type of study. Loss of viral infectivity in samples found to occur during freezing was avoided by addition of broth. Finally, microbial contamination of the cell cultures during infectivity assays was overcome by the use of gentamicin and increased concentrations of penicillin, streptomycin, and amphotericin B.  相似文献   

6.
A comparative evaluation of the determination of acid-detergent fibre (ADF) according to Van Soest and of a modified procedure for the determination of detergent fibre (DF) was performed on 54 forage samples. Losses of cellulose shown to occur during ADF preparation can be avoided by the DF procedure. Despite this finding, true cellulose-contents could be calculated from ADF and ADL, because of non-lignocellulosic contaminants compensating numerically for the cellulose losses.  相似文献   

7.
Cloud robotics has undergone rapid development. As an important candidate for direct-drive manipulator, switched reluctance machines (SRMs) face significant challenge in terms of control used in cloud robotics because of latency and package losses in network communication. In this paper, predictive current control of SRMs is extended to use in controller upon cloud in the face of latency and package losses. The starting point of predictive model is modified to eliminate errors caused by latency in sensor-controller communication, and the execution of control command sequence is dynamically regulated according to the arrival time of the following sequence to adapt for latency and package losses in controller-actuator communication. The proposed control method is evaluated in a 1.5 kW SRM test platform and comparison with a conventional control method is performed; the results show that the proposed control method has better tracking performance in face of time delay and package losses in transmission.  相似文献   

8.
Hiraizumi et al. (1973b) concluded that maternal-fetal ABO incompatibility effect upon the frequency of prenatal deaths was totally absent in two modern Japanese cities, Ohdate and Akita. However, they found a significant heterogeneity in the frequency of prenatal deaths among 16 mating types and suggested that the viability of A-bearing fetuses was higher than that of others, hence the frequency of prenatal deaths decreased with the increasing probability of producing A-bearing fetuses. Further analyses were performed in the present study and the above suggestion was confirmed. Then, the average numbers of prenatal deaths and pregnancies per couple were analyzed separately for their relationships with the probability of producing an A-bearing fetus. The results were found to be consistent with the model that the average numbers of prenatal losses per couple are approximately the same between two groups of matings, one producing and the other not producing A-bearing fetuses, but such losses occur more frequently for the A-bearing fetuses than others at the very early stage of pregnancy such that wives may not recognize such losses. Although the stages of losses are different between A-bearing and other fetuses, the net losses are nearly the same between them, so that such losses will not be reflected in the segregation frequencies among children, as shown by Hiraizumi et al. (1973a).  相似文献   

9.
In order to examine the effect of different lactation weight losses of sows of different parity on subsequent reproductive performance, the present trial was performed in German (n = 4) and Slowakian (n = 11) indoor pig breeding units (n = 1677 sows evaluated). Weaning-to-service-intervals, farrowing rates and total-born litter sizes in sows with different lactation weight losses were compared. Sows were categorized according to lactation weight losses of <5%, 5-10%, 11-15%, 16-20%, >20%. Lactation weight losses exerted a quadratic effect (P < 0.01) on weaning-to-service-intervals. When analyzed across parity categories, with parity category included as a fixed effect, the weaning-to-service-intervals appeared to be minimized at lactation weight losses of <5%. Weaning-to-service-intervals increased (P < 0.05) when lactation weight losses increased above 5% for parity 1 sows, but not until lactation weight losses exceeded 10% for animals of parity 2 and more. There was a parity effect observed at lactation weight losses of <10%, P < 0.05, but the difference was not significant any more at lactation weight losses of >10%. Lactation weight losses >10% had a negative (P < 0.05) effect on subsequent farrowing rates to first service. The difference was higher (P < 0.01) in sows with lactation weight losses >20%. Lactation weight losses exerted a negative (P < 0.001) effect on total-born litter sizes in parity 1 versus parity >5 and parity 1 versus parity 2-5 sows at lactation weight losses of >10%. CONCLUSION: As weight loss of sows during lactation increases subsequent reproduction performance decreases.  相似文献   

10.
Li Q  Qin S  Rao LL  Zhang W  Ying X  Guo X  Guo C  Ding J  Li S  Luo J 《PloS one》2011,6(3):e17544
The vast majority of decision-making research is performed under the assumption of the value maximizing principle. This principle implies that when making decisions, individuals try to optimize outcomes on the basis of cold mathematical equations. However, decisions are emotion-laden rather than cool and analytic when they tap into life-threatening considerations. Using functional magnetic resonance imaging (fMRI), this study investigated the neural mechanisms underlying vital loss decisions. Participants were asked to make a forced choice between two losses across three conditions: both losses are trivial (trivial-trivial), both losses are vital (vital-vital), or one loss is trivial and the other is vital (vital-trivial). Our results revealed that the amygdala was more active and correlated positively with self-reported negative emotion associated with choice during vital-vital loss decisions, when compared to trivial-trivial loss decisions. The rostral anterior cingulate cortex was also more active and correlated positively with self-reported difficulty of choice during vital-vital loss decisions. Compared to the activity observed during trivial-trivial loss decisions, the orbitofrontal cortex and ventral striatum were more active and correlated positively with self-reported positive emotion of choice during vital-trivial loss decisions. Our findings suggest that vital loss decisions involve emotions and cannot be adequately captured by cold computation of minimizing losses. This research will shed light on how people make vital loss decisions.  相似文献   

11.
Homogenization in methanol, two hours of refluxing in methanol, and direct saponification in alcoholic KOH were equally efficient at extracting ergosterol from fungally colonized leaf litter. A 25-cm Li-Chrosphere RP18 HPLC column gave excellent resolution of ergosterol in leaf extracts. Recovery of ergosterol added to leaf powder and methylcellulose ranged between 88 and 97%, but differences among leaf species were not significant. Conditions for liquid-liquid extraction from saponified extracts are critical in ergosterol analysis. Dark storage of samples does not lead to dramatic losses of ergosterol. Extensive sample clean up before HPLC injection is nonessential.  相似文献   

12.
Bombyx mori nucleopolyhedrovirus (BmNPV) disease is one of the most serious silkworm diseases, and it has caused great economic losses to the sericulture industry. So far, the disease has not been controlled effectively by therapeutic agents. Breeding resistant silkworm varieties breeding may be an effective way to improve resistance to BmNPV and reduce economic losses. A precise resistance-detection method will help to accelerate the breeding process. For this purpose, here we described the individual inoculation method (IIM). Details of the IIM include pathogen BmNPV preparation, mulberry leaf size, pathogen volume, rearing conditions, course of infection, and breeding conditions. Finally, a resistance comparison experiment was performed using the IIM and the traditional group inoculation method (GIM). The incidence of BmNPV infection and the within-group variance results showed that the IIM was more precise and reliable than the GIM.  相似文献   

13.

Background  

Infectious bronchitis virus (IBV) is the coronavirus of domestic chickens causing major economic losses to the poultry industry. Because of the complexity of the IBV life cycle and the small number of viral structural proteins, important virus-host relationships likely remain to be discovered. Toward this goal, we performed two-dimensional gel electrophoresis fractionation coupled to mass spectrometry identification approaches to perform a comprehensive proteomic analysis of purified IBV particles.  相似文献   

14.
This paper describes a simple method which uses screen-caged thermocouple psychrometers to measure the water potential components of the roots of cotton (Gossypium hirsutum L.) grown in pots of sand or nutrient solution. Water stress was imposed by withholding irrigation from the sand-grown plants. Sampling was conducted inside a humidified chamber to prevent evaporative losses. The results obtained were within the range expected and comparable to the few published values for other plants. The technique enabled the demonstration of osmotic adjustment in cotton leaves and roots. Published with the approval of the Director of the Arkansas Agricultural Experiment Station.  相似文献   

15.
A field study was conducted to investigate the impact of different patterns of raking and baling operations on the dry matter (DM) and quality losses of the produced alfalfa (Medicago sativa) hay. The experimental work was carried out on a 50?ha center pivot irrigated alfalfa field in a commercial farm located in the Eastern Region of Saudi Arabia. Raking operation was performed following two patterns corresponding to the direction of mowing operation, namely, Raking-I in the same direction of mowing (Mowing→ ?and Raking→) and Raking-II opposite to the direction of mowing (Mowing→ and Raking←). The baling operation; however, was performed following four patterns corresponding to the directions of both mowing and raking operations, namely, Baling-I (Mowing→, Raking→ and Baling→), Baling-II (Mowing→, Raking→ and Baling←), Baling-III (Mowing→, Raking← and Baling→) and Baling-IV (Mowing→, Raking← and Baling←). Results showed that cumulative DM losses in alfalfa hay yield of 30.93% occurred during the harvesting operations. Out of which, raking induced the most DM losses of 985.22?kg?ha?1 (59.66% of the total DM losses and 17.35% of the total hay yield). However, the least DM losses were observed during the baling operation and were estimated at 175.81?kg?ha?1 (10.22% of the total DM losses and 3.10% of the total hay yield). Raking opposite to the direction of mowing reduced the DM losses by 130.17?kg?ha?1 (7.88% of the total DM losses and 2.29% of the total hay yield) compared to that with the direction of mowing. Results also indicated that out of the 21.04% losses in the total crude protein (CP) content of the produced alfalfa hay, 10.91% occurred during the raking operation. However, the baling operation induced the least amount of CP losses (only 2.32% of the total CP). Overall, the best results in terms of alfalfa hay quality and quantity losses were achieved with Baling-III, where the lowest DM losses (2.01% of the total hay yield) and the lowest CP losses (1.44% of the total CP) were recorded.  相似文献   

16.
Using the new Energy-Transport-Reaction Model, the nitrogen-cycle is presented in relation to energy flow in a system. This model is applied exemplary to three degraded inland water bodies. The decrease in the density of energy flow in a spatially limited system provides the framework for this model. By this model the N-cycle can be observed in relation to other abiotic and metabolic processes. The N-cycle proves to be an important indicator, sensitive to disturbances in the hydrologic cycle. A poorly managed hydrologic cycle will increase resource losses from the watershed, and stimulate the formation of loss processes. The model allows an evaluation of a catchment's management according to its ion losses related to its nitrogen losses. Based on a longterm sustainable function of a catchment the integrity of the system is measured by its degree of closure of material cycles and lack of losses. Moreover, loss-minimizing management practices can be derived from the model. Planning and management can be directed towards this goal of minimizing losses and evaluated accordingly.  相似文献   

17.
The G-banding technique was performed on aneuploid karyotypes from gill tissue of the Pacific oyster, Crassostrea gigas, to assess whether chromosome losses could be explained by differential chromosomal susceptibility and to clarify the negative correlation between aneuploidy and growth rate previously reported in different populations of this oyster. The study of 95 G-banded aneuploid karyotypes showed that only 4 of the 10 chromosome pairs (viz. 1, 5, 9, and 10) of C. gigas were affected by the loss of one homologous chromosome. Pairs 1, 9, and 10, which were lost in 56, 33, and 44% of cases, respectively, may be considered to be differentially affected. Hypotheses on this differential chromosomal susceptibility are discussed.  相似文献   

18.
Li YM  Xiang Y  Sun ZQ 《Human heredity》2008,65(3):121-128
Quantitative trait locus (QTL) mapping can be accomplished through the method of selective genotyping, which is based on the differences of frequencies between an upper sample and a lower sample in population. However, amplifying the differences in marker allele frequencies in extreme samples may increase the probability for QTL mapping. Shannon entropy, which is a nonlinear function of allele frequencies, can be used to amplify the differences in marker allele frequencies. In this paper, we present a novel measure for linkage disequilibrium (LD) between a marker and single QTL, that is based on the comparison of the entropy and conditional entropy in a marker in extreme samples of population. This measure of LD between the marker and the trait locus can be used when the marker allele frequencies are known in the extreme samples of a population. We investigate the mapping performance in both analytic and simulation scenarios of a single QTL linked to a single marker. Our results show that the measure has very reasonable performance. In addition, a simulation study is performed on the basis of the haplotype frequencies of 10 SNPs of angiotensin-I converting enzyme (ACE) genes.  相似文献   

19.
Sensory evaluation data obtained from experts were analyzed by numerical methods. The aim of this study is to identify a model that can objectively estimate the sensory evaluation results based on the concentrations of components in sake. To this aim, a learning model in which Dempster-Shafer's measure was learned by genetic algorithm (GA) was constructed. The learning process was performed by discovery of the assignments of basic probabilities according to the decrease in error between the observed and estimated data. When the model was compared with back propagation and multiple regression analysis by cross validation, the predictive faculty of the present model was as good as that of back propagation. The experiential rule by experts for time series data of sensory evaluation could be more sufficiently explained by the present model than by back propagation. The main advantage of this model was that its predictive faculty was compensated by Bayesian probabilities.  相似文献   

20.
C S Weil 《Mutation research》1978,50(2):285-291
A statistical reanalysis was performed on the data fecently reported on a 6-laboratory, collaborative cytogenetic study to measure and minimize interlaboratory variation. Three of the laboratories had mean values significantly different from the others on most of the 6 indexes of chemically-induced aberration; one laboratory with values higher and two with values lower. Furthermore, relative variability of the values around the means was consistently lower in one of the 6 participating laborabories. The results of the reanalysis of this collaborative study demonstrates that significant interlaboratory differences exist and that these should be adjusted or diminished before rat cytogenetic analysis can be an effective test system for evaluation of a compound for mutagenic potential.  相似文献   

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