Regarding the fact that gay men leave less offspring than straight men, it is appropriate to raise a question by which means is male homosexuality maintained in a population and what could eventually be its evolutionary role. The aim of this paper is to summarize theories that try to explain male homosexuality within the framework of evolution. Furthermore, it aims to critically evaluate the results of empirical research that support particular theories or give evidence against them. In the first part, the paper provides a review of knowledge about the genetic and immunological origins of male homosexuality which consequently serves as a theoretical base for the main part of the paper that pursues the five most influential evolutionary theories of male homosexuality. and Homosexuální orientace se vyznačuje trvalou citovou a sexuální náklonností k jedincům stej-ného pohlaví. Vzhledem k tomu, že homosexu-álně orientovaní muži zanechávají méně potom-stva než heterosexuálně orientovaní muži, je na místě si položit otázku, jakými mechanismy je mužská homosexualita v populaci udržována a jaký by případně mohl být její evoluční vý-znam – tedy zda a případně komu (když ne ho-mosexuálnímu jedinci) přináší výhodu ve smy-slu vyššího reprodukčního úspěchu. Cílem této přehledové studie je shrnout teorie, jež se snaží mužskou homosexualitu vysvětlit v evolučním rámci, a kriticky zhodnotit výsledky empiric-kých výzkumů, které podporují jednotlivé teo-rie, či svědčí proti nim. Úvodní část článku po-skytuje přehled poznatků o genetickém a imu-nologickém původu homosexuality u mužů, rovněž však slouží jako teoretický základ pro hlavní část, která se věnuje pěti nejvlivnějším evolučním teoriím mužské homosexuality.
Hlavním cílem článku Hedonismus a eutanazie je ilustrovat komplexní vztahy mezi hédonismem jako teorií welfare a problémem racionality sebeusmrcení, asistovaného sebeusmrcení a eutanazie. Článek je rozdělený na tři části. První část přináší stručný popis hédonismu a vrcholí definicí standardního hédonismu. Druhá část se věnuje problému, zda smrt může v některých (výjimečných) situacích představovat racionálně ospravedlnitelnou volbu. Třetí a konečná část spojuje konsekvencialismus s tradičním hédonismem do standardního utilitarismu a předkládá přímý argument ve prospěch závěru, že asistovaná smrt může být eticky přijatelnou (dokonce povinnou) volbou. Ukazuje však, že hédonismus není adekvátní teorií dobrého života, a proto nakonec etický argument ve prospěch asistované smrti odmítá., The overall aim of the article “Hedonism and Euthanasia” is to illustrate the complex interplay between hedonism as a theory of welfare and the problem of the rationality of suicide, assisted suicide and euthanasia. The article is divided into three parts. In the first part, it provides a succinct description of hedonism culminating in the definition of standard hedonism. The second part deals with the problem of whether death can in some (exceptional) circumstances represent a rationally justifiable choice. The third and final part combines consequentialism with standard hedonism, obtaining standard utilitarianism, and sets forth a straightforward argument for the conclusion that assisted death might be an ethically acceptable (even obligatory) choice. However, hedonism is shown to be an inadequate theory of good life and, consequently, the ethical argument for assisted death is rejected., and David Černý.
An information-theoretic approach was used to evaluate non-native freshwater fish species introduced to insular habitats of Hawaii and Guam comparing successful establishments vs. failures. Since the late 1800s, as many as 81 non-native freshwater fish species have been recorded as introduced to Hawaii and Guam (combined) and 50 (62%) of these are documented as having one or more established populations. We examined eleven independent variables to investigate establishment success by creating 21 a priori logistic regression models ranked using Akaike's Information Criterion adjusted for small sample size. An additional eight post-hoc models were included that comprised the best a priori model and various combinations of individual variables. The best overall model of establishment probability included effects of taxonomic affinity (family membership), prior establishment success on other tropical islands, and hypoxia tolerance. Establishment success in Hawaii and Guam was highest for those species established on many other islands, and according to our best model air-breathing fishes were more likely to become established. Six fish families, each with from three to 18 species introduced to Pacific islands, were highly successful at establishment: Cichlidae (16 established of 18 species introduced), Poeciliidae (seven of eight), Cyprinidae (four of seven), Centrarchidae (four of four), Clariidae (three of three), and Loricariidae (three of four). Those that successfully established include both small and moderately large-bodied taxa, while representing a diverse array of other morphological and life-history traits. Pathways and motives associated with fish introductions in the Pacific have been linked to desires to develop aquaculture, enhance wild stocks of food, sport, and bait fishes, for use as biological control agents, or are linked to the ornamental fish trade. We found that many established species were introduced via multiple pathways (up to eight) and our analyses suggest that the combination of prior establishment success on other tropical islands and presence of non-native fishes in multiple pathways was indicative of high propagule pressure. Our study results and conclusions on Pacific tropical island introductions are in general agreement with previous studies on non-native freshwater fishes in other regions of the world and similar to observations in continental ecosystems and temperate zones.
Many soils and other porous media exhibit dual- or multi-porosity type features. In a previous study (Seki et al., 2022) we presented multimodal water retention and closed-form hydraulic conductivity equations for such media. The objective of this study is to show that the proposed equations are practically useful. Specifically, dual-BC (Brooks and Corey)-CH (common head) (DBC), dual-VG (van Genuchten)-CH (DVC), and KO (Kosugi)1BC2-CH (KBC) models were evaluated for a broad range of soil types. The three models showed good agreement with measured water retention and hydraulic conductivity data over a wide range of pressure heads. Results were obtained by first optimizing water retention parameters and then optimizing the saturated hydraulic conductivity (Ks) and two parameters (p, q) or (p, r) in the general hydraulic conductivity equation. Although conventionally the tortuosity factor p is optimized and (q, r) fixed, sensitivity analyses showed that optimization of two parameters (p + r, qr) is required for the multimodal models. For 20 soils from the UNSODA database, the average R2 for log (hydraulic conductivity) was highest (0.985) for the KBC model with r = 1 and optimization of (Ks, p, q). This result was almost equivalent (0.973) to the DVC model with q = 1 and optimization of (Ks, p, r); both were higher than R2 for the widely used Peters model (0.956) when optimizing (Ks, p, a, ω). The proposed equations are useful for practical applications while mathematically being simple and consistent.
Disruption of the blood-brain barrier (BBB) is a key feature of various brain disorders. To assess its integrity a parametrization of dynamic magnetic resonance imaging (DCE MRI) with a contrast agent (CA) is broadly used. Parametrization can be done quantitatively or semi-quantitatively. Quantitative methods directly describe BBB permeability but exhibit several drawbacks such as high computation demands, reproducibility issues, or low robustness. Semi-quantitative methods are fast to compute, simply mathematically described, and robust, however, they do not describe the status of BBB directly but only as a variation of CA concentration in measured tissue. Our goal was to elucidate differences between five semi-quantitative parameters: maximal intensity (Imax), normalized permeability index (NPI), and difference in DCE values between three timepoints: baseline, 5 min, and 15 min (Δ5-0, Δ15-0, Δ15-5) and two quantitative parameters: transfer constant (Ktrans ) and an extravascular fraction (Ve). For the purpose of comparison, we analyzed DCE data of four patients 12-15 days after the stroke with visible CA enhancement. Calculated parameters showed abnormalities spatially corresponding with the ischemic lesion, however, findings in individual parameters morphometrically differed. Ktrans and Ve were highly correlated. Δ5-0 and Δ15-0 were prominent in regions with rapid CA enhancement and highly correlated with Ktrans . Abnormalities in Δ15-5 and NPI were more homogenous with less variable values, smoother borders, and less detail than Ktrans . Moreover, only Δ15-5 and NPI were able to distinguish vessels from extravascular space. Our comparison provides important knowledge for understanding and interpreting parameters derived from DCE MRI by both quantitative and semi-quantitative methods.
Handy Plant Efficiency Analyser (Handy PEA) provides a method for the high-throughput screening of photosynthetic germplasm. However, the large number of chlorophyll a fluorescence parameters (CFPs) from PEA and the inconsistency of CFP applications among studies greatly limit the accuracy of photosynthesis analyses. In this study, all 53 CFPs of 186 upland cotton cultivars (strains) were measured at 12:00 and 17:00 h. Thirty-two CFPs were selected according to biological importance, and the CFP relationships were determined. Differences in the response ability of cotton cultivars (strains) to high light intensity stress were demonstrated by the distribution of CFPs. Furthermore, the classification and evaluation of photosynthetic characteristics of cotton cultivars (strains) were carried out by Principal Component Analysis and Cluster Analysis. Finally, ten cotton cultivars (strains) with good photosynthetic performance were selected. This study provides a high-throughput method how to identify cotton germplasm resources with high photosynthetic efficiency.
We recently developed a chlorophyll a fluorescence method (activated F0 rise) for estimating if a light wavelength preferably excites PSI or PSII in plants. Here, the method was tested in green microalgae: Scenedesmus quadricauda, Scenedesmus ecornis, Scenedesmus fuscus, Chlamydomonas reinhardtii, Chlorella sorokiniana, and Ettlia oleoabundans. The Scenedesmus species displayed a plant-like action spectra of F0 rise, suggesting that PSII/PSI absorption ratio is conserved from higher plants to green algae. F0 rise was weak in a strain of C. reinhardtii, C. sorokiniana, and E. oleoabundans. Interestingly, another C. reinhardtii strain exhibited a strong F0 rise. The result indicates that the same illumination can lead to different redox states of the plastoquinone pool in different algae. Flavodiiron activity enhanced the F0 rise, presumably by oxidizing the plastoquinone pool during pre-illumination. The activity of plastid terminal oxidase, in turn, diminished the F0 rise, but to a small degree.
Increasing the efficiency of photosynthesis in sugarcane canopies is the key for improving crop yield. Herein, we evaluated the photosynthetic performance along the canopy of ten sugarcane cultivars and three Saccharum species. Canopy morphological traits were evaluated, and leaf gas exchange was measured in the first (sun-exposed, +1) and the fourth (shaded, +4) fully expanded leaves and under low- and high-light conditions. Similar photosynthetic capacity was found in leaves +1 and +4 under high light in genotypes with a high leaf area index and a high fraction of the sky blocked by the foliage (> 85%). Interestingly, such canopy characteristics cause low light availability to leaves +4, suggesting the photosynthetic acclimation of these leaves to self-shading in some genotypes. We highlight IACCTC06-8126 and CTC4 as those genotypes with higher canopy photosynthetic capacity, presenting high leaf area, high photosynthetic rates in sun-exposed leaves, and high responsiveness of shaded leaves to increasing light availability.
A large-scale piano key weir laboratory study was conducted to investigate the evolution of the scour process occurring in the downstream basin for two non-cohesive granular bed materials, including the analysis of scour-hole geometry and patterns at equilibrium. It was observed that hydraulic conditions, particularly tailwater level, significantly affect the scour mechanisms and equilibrium morphology, eventually resulting in scour depths that exceeded the weir height. Unprecedented insights on the scour dynamics are also provided, along with tools to estimate the time evolution and maximum scour depth, its location in the streamwise direction, and the maximum scour length.
Attention Deficit Hyperactivity Disorder (ADHD) is a unique disorder. It usually devel-ops in early childhood and, in 50% of cases, continues to be a lifelong disorder, which poses significant challenges for researchers and clini-cians. The new criteria set by the World Health Organization merged the category of Hyperki-netic Disorders and the ADHD category.This narrative review aims to explore and ease the adoption of the ADHD concept for clinicians and researchers who were used to working with Hyperkinetic Disorders by (1) analyzing the evolution of the ADHD concept from its estab-lishment in the Diagnostic and Statistical Man-ual of Mental Disorders, 3rd edition (DSM-III) until DSM-5; (2) comparing the contemporary concepts of ADHD in DSM-5 and Hyperkinetic Disorders in International Statistical Classifica-tion of Diseases and Related Health Problems (ICD-10); and (3) describing some new chal-lenges the ADHD concept will face in the future.The structure and the dimensions of the concept are explored, including some possible new core symptoms such as emotional dysregulation and mind wandering. Adult presentations of symp-toms of hyperactivity, impulsivity, and inatten-tion are presented. The recent challenges of the global pandemic of covid-19 are also addressed.In conclusion, the concept of ADHD has been dramatically improved since its establishment. However, the bio-psycho-social perspective needs to be better balanced in ADHD-related science. and Porucha pozornosti s hyperaktivitou (ADHD) je unikátní poruchou. Většinou se rozvine v raném dětství a v 50 % případů přerůstá v celoživotní poruchu, což přináší významné výzvy pro vý-zkumníky i odborníky v praxi. Nová kritéria vytvořená Světovou zdravotnickou organiza-cí spojila kategorie hyperkinetických poruch a ADHD. Cílem této narativní přehledové studie bylo prozkoumat a usnadnit osvojení koncep-tu ADHD odborníky a výzkumníky, kteří byli zvyklí pracovat s hyperkinetickými poruchami. 1) Byla analyzována evoluce konceptu ADHD od jeho ustanovení ve 3. edici Diagnostické-ho a statistického manuálu duševních poruch (DSM-III) až po DSM-5; 2) byly porovnány současné koncepty ADHD v DSM-5 a hyper-kinetické poruchy v Mezinárodní statistické klasifikaci nemocí a přidružených zdravotních problémů (MKN-10); a 3) byly popsány některé nové výzvy, kterým může koncept ADHD čelit v budoucnosti. Prozkoumány byly dimenze a struktura konceptu včetně potenciálních no-vých symptomů, jako jsou například emocio-nální dysregulace a tzv. mind wandering. Před-staveny byly také dospělé prezentace symptomů hyperaktivity, impulzivity a nepozornosti. Au-toři se dotkli také nedávných výzev spojených s globální pandemií covid-19. Závěrem lze kon-statovat, že koncept ADHD se od svého vzniku významně zlepšil. Ve vědeckém výzkumu zabý-vajícím se ADHD by však měla být více zohled-něna psycho-bio-sociální perspektiva.