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1.
1 Correspondence address. E-mail: willem.ombelet{at}telenet.be
Although the consequences of the problem of childlessness aremore pronounced in developing countries when compared with Westernsocieties, local health care providers and international organizationspay little attention on this issue. The limited budgets forreproductive health care are mostly restricted to family planningand mother care. The most common misunderstanding is the overpopulation-issue.It is generally believed that the expected growth of the worldpopulation puts a real burden on the issue of infertility treatmentin resource-poor countries, although recent UN reports clearlyshow that in most developing countries the fertility rate isdropping significantly and will fall below the threshold of2.0 by 2050. It seems that the expected population growth indeveloping countries in the next decades is rather due to populationageing and not to high fertility rates. Another important issuesurrounding infertility in developing countries is the so-calledlimited resources argument. Because the problemof childlessness is a major health problem in most developingcountries, a re-arrangement of the global reproductive healthcare budget should be requested from local governments and internationalorganizations taking into account the urgent need for a go-togetherof more successful family-planning policies and affordable simplifiedART methods. 相似文献
2.
Gladki A Siedlecki P Kaczanowski S Zielenkiewicz P 《Bioinformatics (Oxford, England)》2008,24(8):1115-1117
Summary: Using literature databases one can find not only knownand true relations between processes but also less studied,non-obvious associations. The main problem with discoveringsuch type of relevant biological information is selection.The ability to distinguish between a true correlation (e.g.between different types of biological processes) and randomchance that this correlation is statistically significant iscrucial for any bio-medical research, literature mining beingno exception. This problem is especially visible when searchingfor information which has not been studied and described inmany publications. Therefore, a novel bio-linguistic statisticalmethod is required, capable of selecting truecorrelations, even when they are low-frequency associations.In this article, we present such statistical approach basedon Z-score and implemented in a web-based application e-LiSe. Availability: The software is available at http://miron.ibb.waw.pl/elise/ Contact: piotr{at}ibb.waw.pl Supplementary information: Supplementary materials are availableat http://miron.ibb.waw.pl/elise/supplementary/
Associate Editor: Alfonso Valencia 相似文献
3.
Hama Takeo; Matsunaga Katsuji; Handa Nobuhiko; Takahashi Mikio 《Journal of plankton research》1990,12(1):125-131
The production rate of participate nitrogen (PN) in Lake Biwafrom March to June 1986 was calculated by monthly measurementsof the proteinaceous nitrogen production rates. The newproduction rate was estimated from the decrease in nitrate inthe euphotic zone; during this period (91 days) it was estimatedas 93 mg atoms m2, and accounted for 20% of the totalPN production (460 mg atoms m2). This implies that {smalltilde}80% of the PN produced might be recycled in the euphoticzone. The increase in PN in the euphotic zone during this period(27 mg atoms m2) accounted for 5.9% of the totalPN production. This indicates that the remaining 14% of PN producedin the euphotic zone was vertically transported. Sediment trapexperiments at 30 m depth indicate that 8.1% of the PN producedin the euphotic zone was measured as downward flux at 30 m depthduring the stagnation period. Decompositional loss of PN between12.5 (bottom of the euphotic zone) and 30 m depth was estimatedas 17 mg atoms m2. This was calculated on the basis ofaccumulation of ammonium, which accounted for 3.7% of the totalPN production. The flux from the euphotic zone thus accountedfor 12% of the total PN production, suggestingthe validity of the production model. 相似文献
4.
Loh AM Wiltshire S Emery J Carter KW Palmer LJ 《Bioinformatics (Oxford, England)》2008,24(9):1210-1211
Summary: Traditional two-dimensional (2D) software programsfor drawing pedigrees are limited when dealing with extendedpedigrees. In successive generations, the number of individualsgrows exponentially, leading to an unworkable amount of spacerequired in the horizontal direction for 2D displays. In addition,it is not always possible to place closely related individualsnear each other due to the lack of space in 2Ds. To addressthese issues we have developed three-dimensional (3D) pedigreedrawing techniques to enable clearer visualization of extendedpedigrees. Currently no other methods are available for displayingextended pedigrees in 3Ds. We have made freely available a softwaretool—Celestial3D—that implements thesenovel techniques. Availability: Freely available to non-commercial users Contact: celestial3d{at}genepi.org.au Supplementary information: www.genepi.org.au/celestial3d
Associate Editor: Martin Bishop
1A more extensive list of software tools appears in the SupplementaryMaterial. 相似文献
5.
6.
MAGIC Tool: integrated microarray data analysis 总被引:5,自引:1,他引:4
Heyer LJ Moskowitz DZ Abele JA Karnik P Choi D Campbell AM Oldham EE Akin BK 《Bioinformatics (Oxford, England)》2005,21(9):2114-2115
Summary: Several programs are now available for analyzing thelarge datasets arising from cDNA microarray experiments. Mostprograms are expensive commercial packages or require expensivethird party software. Some are freely available to academicresearchers, but are limited to one operating system. MicroArrayGenome Imaging and Clustering Tool (MAGIC Tool) is an open sourceprogram that works on all major platforms, and takes users fromtiff to gif. Several unique features of MAGIC Tool areparticularly useful for research and teaching. Availability: http://www.bio.davidson.edu/MAGIC Contact: laheyer{at}davidson.edu 相似文献
7.
1 Correspondence address. E-mail: petra.desutter{at}ugent.be In 2% of assisted reproductive techniques (ART) cycles complicationsoccur. Some are preventable, some are not. In this paper, wewill discuss risks and complications of the standard Westernapproach in ART today and point to some measures to be takenwhen implementing ART in developing countries, where resourcesand access to medical care may be limited. Ovarian hyperstimulationsyndrome (OHSS, and its thrombo-embolic complications) is responsiblefor the majority of cycle-related complications, followed bybleeding and infection at oocyte retrieval. ART pregnanciesare complicated by first-trimester bleeding more often thanspontaneous pregnancies, they are more often ectopic, but themajor complication is the very high incidence of multiple pregnancies,when more than one embryo is transferred. OHSS can be preventedby screening patients at risk and by using mild or no stimulation.Simple measures can minimize the risks of bleeding or infection.Obviously single embryo transfer is the only way to avoid multiplepregnancies, which have a highly increased risk for severe maternaland neonatal morbidity and mortality (mainly due to prematurity).Special attention should be given to pre-existing pathologies.Risk minimization of ART in developing countries is not onlymandatory from an economical but also an ethical point of view. 相似文献
8.
《Journal of experimental botany》1977,28(6):1247
Effects of coupled solute and water flow in plant roots withspecial reference to Brouwer's experiment. Edwin L. Fiscus. p. 71 Abstract: Line 3 delete interval insertinternal. p. 73 Materials and Methods: line 6: delete diversion insert division line 9 equation should read Jv=Lp PRT(C0C1). 74 Last line of figure legend: 101 should read 1011. 75 Line 11: delete seems insert seem. le 1 column heading106 should read 1011. 77 delete ...membrane in series of... insert membranein series or... Delete final paragraph. 相似文献
9.
Pattern of Respiration of a Perennial Ryegrass Crop in the Field 总被引:3,自引:0,他引:3
Dark respiratory losses of CO2 were measured ona one year old sward of S24 perennial ryegrass (Lolium perenneL.) at intervals during a 74 day reproductive growth period,between April and June, and a 21 day vegetative growth period,in July and August. Part of the sward was shaded for one weekbefore measure ments commenced. Measurements of darkrespiration continued for 46 hand it was possible to distinguishtwo components which are designated maintenanceand synthetic Maintenance respiration was taken to be the meanrate of CO2 efflux after 4046 h darkness. When calculatedon a plant d. wt basis at 15°C it ranged between 6 to 32mgCO2 g-1 day-1 during reproductive growth and 1014 mgCO2 g-1 day-1 during vegetative growth. During reproductivegrowth, sward protein content ranged between 723 percent and when maintenance respiration was recalculated on thebasis of protein content it changed relatively little throughoutthe growth period (90140 mg CO2 g pro tein-1 day-1);the value for vegetative growth ranged between 70100mgCO2 g protein-day-1. Total synthetic CO2 flux was determined duringreproductive growth and a rate of synthetic CO2flux was determined during both reproductive and vegetativegrowth. Between 15 and 35 per cent of the CO2 fixed in the previousphotoperiod was lost in synthetic respirationof above-ground material in reproductive swards. Previous shadingincreased the proportion of synthetic CO2 lossfrom above ground. The rate of synthetic CO2 outputduring the first hours of darkness increased with amount ofCO2 fixed in the previous photoperiod, although it was not proportionalto it. There is some evidence that assimilate is carried-overfrom one photoperiod to the next. 相似文献
10.
KANAMORI-FUKUDA IKUKO; ASHIHARA HIROSHI; KOMAMINE ATSUSHI 《Journal of experimental botany》1981,32(1):69-78
Marked changes in the activity of the de novoand salvage pathways of pyrimidine biosynthesisduring growth of Vinca rosea cells in a batch suspension culturewere observed. The activity of these pathways was investigated by determiningthe contribution of 14C of [2-14Cluracil, 12-14Cluridine. and[6-14Clorotate to the cell constituents and by measuring theactivity of the several enzymes of these pathways. During the lag phase of the culture, uracil- anduridine-salvage pathways made the predominantcontribution to nucleotide biosynthesis, but, following theinitiation of cell division, the de novo pathwayfor nucleotide biosynthesis operated appreciably. These results suggest that nucleotide synthesis during cellgrowth in a suspension culture can be divided into two stages:a turnover stage, during the lag phase of cellgrowth, and a true biosynthetic stage, which isinitiated in the cell division phase. 相似文献
11.
Predator-prey interactions: is 'ecological stoichiometry' sufficient when good food goes bad? 总被引:4,自引:1,他引:3
The dietary value of a prey type varies with its nutritionalstatus and hence with its C:N:P content. However, while stoichiometricdifferences between a heterotroph and its food must affect growthefficiency (GE), and thence trophic dynamics, other factorsrelated to food quality may act as powerful modulators of predatorpreyinteractions. Thus, minor changes in prey stoichiometry canbe associated with more significant changes in prey quality(production of toxins, mucus, thicker walls etc.) that may havea disproportionate effect on predation rates and GE. We termthe predator response to such events, stoichiometricmodulations. Often these modulations are negative, decreasingpredation and assimilation rates. We suggest that due considerationshould be given in the construction of multinutrient-based modelsof predators to the processes of prey selectivity, ingestionand digestion as functions of food quality with quantity.
Written responses to this article should be submitted to RogerHarris at rph{at}pml.ac.uk within two months of publication. Forfurther information, please see the Editorial Horizonsin Journal of Plankton Research, Volume 26, Number 3, Page 257 相似文献
12.
Effect of Inorganic Phosphate on the Biosynthesis of Purine and Pyrimidine Nucleotides in Suspension-Cultured Cells of Catharanthus roseus 总被引:1,自引:0,他引:1
The levels of purine and pyrimidine nucleotides in suspensioncultures of Catharanthus roseus were determined 24 h after stationary-phasecells were transferred to fresh complete (+Pi)or phosphate-deficient (Pi) Murashige-Skoogmedium. The levels of ATP, GTP, UTP and CTP were from approx.3 to 5-fold greater in the cells grown in +Pimedium than in the cells grown in Pi medium.The levels of almost all other nucleotides were slightly higherin the cells in +Pi medium. The rates of de novoand salvage biosynthesis of purine and pyrimidine nucleotideswere estimated from the rates of incorporation of radioactivityfrom [14C]formate, [214C]glycine, NaH14CO3, [614C]orotate,[814C]adenine, [814C]adenosine, [214C]uraciland [214C]uridine. The results indicated that the activityof both the de novo and the salvage pathway was higher in thecells in +Pi medium than in the cells in Pimedium. The rate of degradation estimated from the rate of releaseof 14CO2 from labelled purines and pyrimidines indicated thatdegradation of uridine was significantly reduced in the cellsin +Pi medium, but no significant difference wasfound in the degradation of adenine, adenosine and uracil. Thepossible role of Pi in the control of the biosynthesis of nucleotidesand in the degradation of uridine is discussed. Catharanthus roseus, Madagascar periwinkle, suspension culture, inorganic phosphate, nucleotides, purines, pyrimidines, biosynthesis, degradation 相似文献
13.
Feeding behavior of the brittle star Ophiura ophiura includesorienting posture, orienting movements, arm walking,changing the direction of walking arm coilingand ingestion. All sequential behavior patterns were releasedor enhanced by single low-molecular-weight compounds. Stimuliwhich released walking behavior at high concentrations(104 M) in all the test animals are listed in decreasingorder of sensitivity: sarcosine, glycine, urea, L-valine, L-leucine,L-methionine, L-homocysteine, L-norvaline, L-norleucine, L-threonine,L-serine, S-methyl-L-cysteine, L-proline. Threshold values forsingle amino acids were as much as 100 times different in differentindividuals and ranged from 3 x 109 to 3 x 107M for the most effective stimulus, sarcosine, and from 106to 104 M for proline. Above 105 M, only L-prolineregularly released a second behavior pattern, the arm coilingresponse, which temporarily inhibited the walkingbehavior. Behavioral thresholds for the walkingbehavior for L(+)-lactate and L-alanine were higher than thosefor the orienting movements. Thyoglycolic acid and ß-alaninereleased tube feet walking, which is not part of the feedingbehavior. Structureactivity comparisons were studied at estimated105 M concentrations. Gycline, sarcosine, L-valine, L-norvaline,L-leucine, L-isoleucine, DL-norleucine and DL-homocysteine releasedarm walking behavior in more than 75% of all thetests. With the exceptions of S-methyl-and S-ethyl-cysteine,and glycine methylester, derivatives of amino acids were noteffective behavioral stimuli in Ophiura ophiura. L-Isomers ofvaline and leucine regularly stimulated the walkingbehavior while their D-isomers were effective in some testsand ineffective in others. Acetylcholine iodide, acetyl-ß-methylcholine chloride and choline phosphate chloride regularly releasedwalking behavior at concentrations above 105M. 相似文献
14.
The effect of the leafless mutation (in whichtendrils replace leaflets and the stipules are reduced to avestigial form) upon foliage area, photosynthetic net CO2 uptakepotential, dry matter production and seed yield in Pisum sativumwas studied by comparing two near-isogenic lines of genotypeafafstst and ++++. The mutation is of potential agronomic valuein that it offers improved lodging resistance, crop drying andharvester throughput. In the conventional phenotype the total foliage area of themain axis attained a plateau (456 cm2) at day 56 from seedlingemergence, whereas corresponding values for the leaflessmutant showed a total area of 208 cm2 at day 68 with no indicationof a plateau. The agronomic consequence of this is discussed.During the vegetative phase of the plant the maximum CO2 uptakepotential in the fully expanded conventional leaf was 8·5mg CO2 leaf1 h1 and in the leaflessmutant this value was 7·0 mg CO2 leaf1 h1.For most leaves of the latter phenotype this valuewas between 30 and 60 per cent less than for their conventionalcounterpart. There was a consistently higher photosyntheticpotential per unit area in tendrils of the leaflessmutant than in leaflets of the conventional phenotype. The respectivemean specific values for the two phenotypes were 53 and 37 mgCO2 dm2 h1. The problem of obtaining a meaningfulsurface area value for tendrils is discussed and the cylindricalnature of tendrils is taken into account. The leafless mutant consistently accumulated 50per cent less dry matter than did conventional plants in theperiod from seedling emergence to anthesis and yield of maturedry seed per plant showed a reduction of 50 per cent both inseed number and total seed weight. The implications for future breeding and selection programmesaimed at haulm reduction are discussed in relation to evaluatingthe ability of the background genotype to produce adequate tendrilsin the presence of afafstst. Triticum aestivum, wheat, callus culture, organogenesis 相似文献
15.
Data consisting of high resolution profiles of in situ chlorophyll,copepods and primary production have been measured with a towedBatfish and profiling pumping system at two sites named BIOSTAT(9°45'N, 93°45'W) and DOME (7°19'N,83°25'W) sites during March 1981. Primary production profileswere generated from Batfish profiles using a chlorophyll/lightmodel and incubated pump samples, the latter with high verticalresolution of 35 m. The BIOSTAT site had a subsurfacechlorophyll maximum situated at {small tilde}50 m, and a productionmaximum at a depth of 40 m Copepods had a mean depth centroidcorresponding to the production maximum although their distributionwas more uniformly dispersed from 0 to 40 m. The latter observationindicated that copepods occurred at depths of high productionpotential and low biomass rather than high total productionand high biomass as found at 40 m depth. The DOME site had amixed surface layer of chlorophyll (020 m) while copepodswere located at the base of the chlorophyll layer and primaryproduction maximum located at the surface (010 m). Theareal daily production measured at the BIOSTAT and DOME siteswere 0.27 and 0.80 mg C m2day1 respectively. 相似文献
16.
The Sensitivity of Net Photosynthesis in Several Plant Species to Short-term Fumigation with Sulphur Dioxide 总被引:4,自引:0,他引:4
The effects of exposure of up to 2 h with sulphur dioxide ona range of plant species was observed by measuring changes inthe rate of net photosynthesis under closely controlled environmentalconditions. Ryegrass, Lolium perenne S23 was thespecies most sensitive to SO2; significant inhibition was detectedat 200 nl l1. Fumigations at 300 nl l1 also inhibitedphotosynthesis in field bean (Vicia faba cv. Three FoldWhite and Blaze) and in barley (Hordeumvulgare cv. Sonja). No effect was detected inwheat (Triticum aestivum cv. Virtue) at concentrationsup to 600 nl l1 SO2, or in oil-seed rape (Brassica napuscv. Rafal) except at 800 nl l1 SO2). Recoverycommenced immediately after the fumigation was terminated andwas complete within 2 h when inhibition had not exceeded 20%during the SO2 treatment. Key words: Sulphur dioxide, short-term fumigation, photosynthesis 相似文献
17.
Abstract line 12: for below 2.03, 0.53 and 0.28 mequiv.K+l1 respectively read below 0.28, 0.53and 2.03 mequiv. K+l1 respectively. 相似文献
18.
Algal 14C and total carbon metabolisms. 1. Models to account for the physiological processes of respiration and recycling 总被引:1,自引:0,他引:1
A consistent set of equations has been written to describe thenet rate of algal 14CO2 uptake (and where appropriate respirationand photosynthesis) which take into account separately complicationsdue to respiration of the labelled photosynthetic products andthe recycling of respiratory CO2. Written specifically intothe equations is the concept of new and oldcarbon, the coefficient q is used in the respiration model toallow for the differential respiration of organic material fromthe new and old carbon pools. Analyticalintegrals have been found for respiration and recycling models,and the behaviour of the models studied over periods of 12 h(i.e. up to 70% of the intrinsic generation time). The rateconstant for respiration has a greater effect on the behaviourof the recycling than the respiration model. Over short timecourses (up to 30% of the intrinsic generation time), the effectsof respiration and recycling on net 14CO2 uptake are quite distinct,especially at high P/R ratios, and not complicated by assumptionsover the value of q. Although the value of q will have a time-dependentsecondary effect on the modelled total carbon-specific respirationrate, this was found not to give rise to major problems of interpretation.Beyond 50% of the intrinsic generation time, the separate treatmentof respiration and recycling in the models becomes less satisfactory.It was concluded that the present equations, which are not constrainedby mass balance considerations, would not be appropriate fora model that combines the two processes. The pattern of recyclingat low P/R values is identified as one of the major uncertaintiesin producing models of 14C uptake. The effect of the releaseof dissolved organic material can be anticipated in a generalway. The models have been used to define an experimental strategyto establish the separate effects of respiration and recyclingon the time course of net 14C uptake. The initial rates givethe clearest resolution of the two processes and it would appearthat with photosynthetic rates in the region of 1 day1,incubation periods up to 36 h would be suitable to determinethe importance of recycling in controlling net 14C uptake. Withthe present models, only in the absence of recycling could theeffect of respiration be studied and the value of q established. 相似文献
19.
Floral buds of the False Horn plantain clonesMusa (AAB) Harton Verde, Harton Negra,and Currare terminate in a large single floralstructure. The apices of these floral buds are here designatedas determinate since they have lost the ability to produce additionalfloral initials or buds. Terminal peduncle segments can be culturedin a modified Murashige and Skoog (1962) medium supplementedwith N6-benzyl-aminopurine (5 mg I1). Under these conditions,this apparent inability to yield buds can be overcome as vegetativeshoot clusters form in the axils of the bracts. Rooted plantletsare obtainable by treating shoots with naphthaleneacetic acid(1 mg I1) and activated charcoal (0.025%). The adventitiousorigin of the shoots has been established. Musa cultivars, plantains, floral bud, adventitious buds, tissue culture 相似文献
20.
Nitrate provision has been found to regulate the capacity forChara corallina cells to take up nitrate. When nitrate was suppliedto N sufficient cells maximum nitrate uptake was reached after8 h. Prolonged treatment of the cells in the absence of N alsoresulted in the apparent ability of these cells to take up nitrate.Chlorate was found to substitute partially for nitrate in theinduction step. The effects on nitrate reductionwere separated from those on nitrate uptake by experiments usingtungstate. Tungstate pretreatment had no effect on NO3uptake induced by N starvation, but inhibitedNO3 uptake associated with NO3 pretreatment. Chloridepretreatment similarly had no effect on NO3 uptake inducedby N deprivation, but inhibited NO3 uptake followingNO3 pretreatment. The data suggest that there are atleast two mechanisms responsible for the inductionof nitrate uptake by Chara cells, one associated with NO3reduction and induced by CIO3 or NO3and one associated with N deprivation. Key words: Nitrate, Chlorate, Chara corallina, Induction 相似文献