selection effects
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We explored the transition of 13 X-linked markers across two separate portions of the house mouse hybrid zone, asking whether such a comparison can distinguish the effects of selection from random factors. A heuristic search in the likelihood landscape revealed more complex likelihood profiles for data sampled in two-dimensional (2D) space relative to data sampled along a linear transect. Randomized resampling of localities analyzed for individual loci showed that deletion of sites away from the zone center can decrease cline width estimates whereas deletion of sites close to the center can significantly increase the width estimates. Deleting localities for all loci resulted in wider clines if the number of samples from the center was limited. The results suggest that, given the great variation in width estimates resulting from inclusion/exclusion of sampling sites, the geographic sampling design is important in hybrid zone studies and that our inferences should take into account measures of uncertainty such as support intervals. The comparison of the two transects indicates cline widths are narrower for loci in the central part of the X chromosome, suggesting selection is stronger in this region and genetic incompatibilities may have at least partly common architecture in the house mouse hybrid zone.
- MeSH
- druhová specificita MeSH
- genetické markery genetika MeSH
- genotyp MeSH
- hybridizace genetická MeSH
- myši genetika MeSH
- pravděpodobnostní funkce MeSH
- rozmnožování genetika MeSH
- selekce (genetika) MeSH
- stochastické procesy MeSH
- vznik druhů (genetika) MeSH
- zeměpis MeSH
- zvířata MeSH
- Check Tag
- myši genetika MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Geografické názvy
- Česká republika MeSH
- Německo MeSH
Sexually reproducing organisms require males and females to find each other. Increased difficulty of females finding mates as male density declines is the most frequently reported mechanism of Allee effects in animals. Evolving more effective mate search may alleviate Allee effects, but may depend on density regimes a population experiences. In particular, high-density populations may evolve mechanisms that induce Allee effects which become detrimental when populations are reduced and maintained at a low density. We develop an individual-based, eco-genetic model to study how mating systems and fitness trade-offs interact with changes in population density to drive evolution of the rate at which males or females search for mates. Finite mate search rate triggers Allee effects in our model and we explore how these Allee effects respond to such evolution. We allow a population to adapt to several population density regimes and examine whether high-density populations are likely to reverse adaptations attained at low densities. We find density-dependent selection in most of scenarios, leading to search rates that result in lower Allee thresholds in populations kept at lower densities. This mainly occurs when fecundity costs are imposed on mate search, and provides an explanation for why Allee effects are often observed in anthropogenically rare species. Optimizing selection, where the attained trait value minimizes the Allee threshold independent of population density, depended on the trade-off between search and survival, combined with monogamy when females were searching. Other scenarios led to runaway selection on the mate search rate, including evolutionary suicide. Trade-offs involved in mate search may thus be crucial to determining how density influences the evolution of Allee effects. Previous studies did not examine evolution of a trait related to the strength of Allee effects under density variation. We emphasize the crucial role that mating systems, fitness trade-offs and the evolving sex have in determining the density threshold for population persistence, in particular since evolution need not always take the Allee threshold to its minimum value.
- MeSH
- biologická evoluce * MeSH
- genetická zdatnost * MeSH
- hustota populace MeSH
- modely genetické MeSH
- sexuální výběr u zvířat * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
... SUPPLEMENT 1 | JANUARY 2021 | www.laryngoscope.com -- PEDIATRICS -- EFFICIENT POSTOPERATIVE DISPOSITION SELECTION ...
The laryngoscope, ISSN 0023-852X Volume 131, supplementum 1, 2021
10 stran : ilustrace ; 28 cm
- MeSH
- dítě MeSH
- efektivita organizační MeSH
- kvalita zdravotní péče MeSH
- laryngoskopie MeSH
- péče o pacienty v kritickém stavu MeSH
- pooperační péče MeSH
- výsledek terapie MeSH
- Check Tag
- dítě MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- dětská chirurgie
- otorinolaryngologie
- NLK Publikační typ
- brožury
Uvedením antipsychotik druhé generace do klinické praxe se značně zkvalitnila léčba schizofrenie. Při výběru konkrétního léku je však nutné zvažovat kromě ovlivnění cílových příznaků zejména profil nežádoucích účinků daného léku. Hlavním vedlejším účinkem antipsychotik první generace jsou zejména extrapyramidové nežádoucí účinky či hyperprolaktinémie, která je společně s obezitou, hyperglykemií, hyperlipidemií či kardiálními komplikacemi považována za hlavní rizika spojená s léčbou antipsychotiky druhé generace. Lékaři musí totiž zodpovědně posoudit užitek i případná rizika spojená s nežádoucími účinky zvoleného antipsychotika. Výběr vhodného antipsychotika musí být proto přísně individuální s ohledem profitu na straně jedné a případných rizik na straně druhé.
- MeSH
- antipsychotika farmakologie škodlivé účinky MeSH
- benzodiazepiny farmakologie škodlivé účinky MeSH
- diabetes mellitus MeSH
- diferenciální diagnóza MeSH
- financování organizované MeSH
- fyziologické účinky léků MeSH
- hyperprolaktinemie MeSH
- klozapin farmakologie škodlivé účinky MeSH
- krevní glukóza účinky léků MeSH
- lidé MeSH
- obezita MeSH
- prolaktin účinky léků MeSH
- schizofrenie farmakoterapie MeSH
- syndrom dlouhého QT MeSH
- tělesná hmotnost účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
V pokusech na samcích potkana byl sledován vliv vybraných anticholinergik (atropin, benaktyzin, biperiden) na účinek nového asymetrického biskvarterního oximu BI-6 vůči cholinergním a stresogenním účinkům vysoce toxického organofosfátu somanu. Somanem indukovaná inhibice acetylcholinesterázy v krvi, bránici či v CNS, stejně jako somanem vyvolaná hyperkortikosteronemie a zvýšení aktivity tyrozin aminotransferázy v játrech, byly daleko výrazněji ovlivněny oximem BI-6 v kombinaci s benaktyzinem nebo biperidenem než v kombinaci s atropinem. Získané výsledky svědčí o tom, že benaktyzin či biperiden jsou pro terapii akutní intoxikace somanem výhodnějšími anticholiner- giky, než dosud používaný atropin, je-li tato intoxikace léčena oximem BI-6.
The experiments in male rats investigated the influence of selected anticholinergic drugs (atropin, benactyzin, biperiden) on the effect of a new asymmetric bisquarternary oxime BI-6 against cholinergic and stressogenic effects of the highly toxic organophos- phate soman. The soman-induced inhibition of acetylcholinesterase in blood, diaphragm or CNS, as well as the soman-induced hypercorticosteronemia and increased activity of tyrosine aminotransferase in liver, were markedly more influenced by oxime BI-6 in combination with benactyzin or biperidine than in combination with atropin. The results obtained appear to indicate that benactyzin or biperiden are anticholinergic drugs which represent therapeutic advantage over the so far used atropin, if the poisoning is treated with oxime BI-6.
- MeSH
- acetylcholin antagonisté a inhibitory metabolismus MeSH
- atropin farmakologie MeSH
- benaktyzin farmakologie MeSH
- biperiden farmakologie MeSH
- fyziologický stres farmakoterapie chemicky indukované MeSH
- krysa rodu rattus MeSH
- oximy farmakologie chemie MeSH
- soman toxicita MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- srovnávací studie MeSH
Destination therapy with a left ventricular assist device (LVAD) has the potential to effectively treat a large number of patients with advanced heart failure who are not eligible for heart transplantation. With the advent of continuous-flow LVADs, safe and effective long-term circulatory support is available for properly identified candidates. RECENT FINDINGS: The highest mortality following LVAD implant is observed in the sickest patients (INTERMACS profile 1); therefore, there is an increasing trend toward selecting patients with INTERMACS profiles 2-5. The less-ill patients will be studied in the planned REVIVE-IT trial. The Heart Failure Survival Score, Seattle Heart Failure Model, and Destination Therapy Risk Score may provide guidance for patient selection and preoperative optimization therapy, but these tools need to be updated for current LVAD technology. The current 1-year survival rate for patients supported for destination therapy with a continuous-flow LVAD is 74%, which represents an increase of 6% since the clinical trial was completed 2 years ago. SUMMARY: Substantial progress has been made concerning survival and quality of life since destination therapy was first introduced 10 years ago. Advances in patient selection, improved LVAD technology, and optimized treatment strategies provide much optimism for the treatment of more heart failure patients in the future.
- MeSH
- analýza přežití MeSH
- hodnocení rizik MeSH
- lidé MeSH
- podpůrné srdeční systémy MeSH
- progrese nemoci MeSH
- srdeční komory MeSH
- srdeční selhání mortalita terapie MeSH
- výběr pacientů MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
- Geografické názvy
- Spojené státy americké MeSH
Selective hunting can affect demographic characteristics and phenotypic traits of the targeted species. Hunting systems often involve harvesting quotas based on sex, age and/or size categories to avoid selective pressure. However, it is difficult to assess whether such regulations deter hunters from targeting larger "trophy" animals with longer horns that may have evolutionary consequences. Here, we compile 44,088 annually resolved and absolutely dated measurements of Alpine ibex (Capra ibex) horn growth increments from 8,355 males, harvested between 1978 and 2013, in the eastern Swiss Canton of Grisons. We aim to determine whether male ibex with longer horns were preferentially targeted, causing animals with early rapid horn growth to have shorter lives, and whether such hunting selection translated into long-term trends in horn size over the past four decades. Results show that medium- to longer-horned adult males had a higher probability of being harvested than shorter-horned individuals of the same age and that regulations do affect the hunters' behaviour. Nevertheless, phenotypic traits such as horn length, as well as body size and weight, remained stable over the study period. Although selective trophy hunting still occurs, it did not cause a measurable evolutionary response in Grisons' Alpine ibex populations; managed and surveyed since 1978. Nevertheless, further research is needed to understand whether phenotypic trait development is coinfluenced by other, potentially compensatory factors that may possibly mask the effects of selective, long-term hunting pressure.
- MeSH
- fenotyp MeSH
- kozy genetika růst a vývoj MeSH
- lidské činnosti * MeSH
- rohy růst a vývoj MeSH
- selekce (genetika) * MeSH
- sporty MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Švýcarsko MeSH
1. Changes in embryonic development and growth were analysed in relation to direct changes in postnatal growth and correlated responses in egg parameters using Japanese quail lines selected for more than 30 generations for high (HG) and low (LG) relative gain of body weight (BW) between 11 and 28 d of age, and constant BW at 49 d of age. 2. During the first 42 h as well as at the end of incubation, LG embryos were developmentally accelerated in comparison with their HG counterparts. An expected increase of line divergence across generations was observed only in traits analysed at the end of incubation. 3. In contrast to early generations, LG embryos continuously exhibited a higher BW than HG embryos and this difference temporarily disappeared only around incubation d 8. Analogous to early generations, the HG compared with LG embryos showed two periods of transient growth retardation compensated subsequently by a higher growth rate (incubation d 3-8 and 8-16). 4. More pronounced growth retardation of HG versus LG embryos in late versus early generations corresponded to more distinct decrease of HG versus LG growth rate during the first post-hatch days. Likewise, a disappearance of line BW differences on incubation d 8 characterising the late generations corresponded to the elimination of line differences in adult BW. 5. Alterations of growth pattern were associated with changes of egg size. While HG quail maintained a relatively constant adult BW and egg size across generations, the gradually increasing incidence of large eggs in the LG line allowed selection of birds with higher growth potential, which in turn amplified the line differences in the embryonic BW and eliminated the line differences in adult BW. Line differences in egg composition (larger albumen with lower density in LG compared with HG eggs) apparently contributed to the strengthening of line developmental divergence during incubation. 6. Transient lack of nutrient supply to HG embryos due to their developmental delay is probably responsible for a higher HG versus LG embryo mortality.
- MeSH
- časové faktory MeSH
- Coturnix embryologie genetika růst a vývoj MeSH
- embryonální vývoj genetika MeSH
- selekce (genetika) * MeSH
- tělesná hmotnost genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH