National Repository of Grey Literature 25 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Diversity of iris coloration during evolution of geckos (Gekkota)
Ozerskyi, Serhii ; Brejcha, Jindřich (advisor) ; Šmíd, Jiří (referee)
Iris is an anatomical structure that performs the function of a diaphragm in the visual system of the eye. It usually occupies most of the visible part of the eye. In addition to the main function - not to let light pass by the pupil, iris can play many different roles due to the great variability of its coloration. Iris can be part of a camouflage or aposematic color, play a different role in intra- or interspecific communication. In some species, its color changes depending on age, season, biological cycles, or even quickly become marked in response to stimuli. Geckos (Gekkota) are distinguished by a particularly large variety of iris color. And in many of them, the iris pattern resembles branching veins. What significance and evolution history this pattern has is of interest. I used various models of evolutionary reconstruction in the R program to study the evolution of veined pattern of coloration of the iris, as well as phylogenetic comparative methods and binary character evolution model to identify its connections with the fusion of life and the contrast in brightness between the eye and the eye ring. It was revealed that the veined pattern is an ancestral condition for geckos and is present in most modern species. Most precisely, the evolution of the vein pattern is described by all rates different...
Diversity and phylogeny of the lacertid lizards (Lacertidae) with emphasis on the tribe Eremiadini
Hlaváč, Denis ; Šmíd, Jiří (advisor) ; Chmelař, Jan (referee)
The family Lacertidae (lizards) belongs to the class Reptilia (reptiles) and the order Squamata (scaly reptiles). This family consists of two subfamilies, Lacertinae and Gallotinae, which are diversified into 45 genera and approximately 368 species. The subfamily Lacertinae is divided into two tribes, namely the tribus Eremiadini and Lacertini. The tribe Lacertini can be further divided into two clades: the Ethiopian and the Saharan-Eurasian clade. The subfamily Lacertinae, with approximately 354 species, is much larger than the subfamily Gallotinae, which consists of only 14 species. From the subfamily Lacertinae, the larger tribus Eremiadini is formed by 215 species classified in 22 genera. Representatives of this family can be found in Europe, Africa and Asia, but the center of origin is Europe. They belong to the dominant species of herpetofauna in Europe. The Eremiadini tribe separated from the rest of the Lacertidae family in the past and migrated to Africa, where it diversified into its present form. Currently, the diversity of the Eremiadini tribe is concentrated in Africa, but a large number of species also occur in Asia. The body is small to medium in size, which usually does not exceed 90 mm without the tail. The body shape is slender and the tail is relatively long compared to the body...
Prevalence of Atrial Fibrillation as a Risk Factor in Patients after Circulatory Arrest for Ventricular Fibrillation
Šmíd, Jiří ; Vančura, Vlastimil (advisor) ; Mayer, Otto (referee) ; Skalická, Hana (referee)
Atrial fibrillation is the most common arrhythmia occurring in the adult population. Sudden cardiac death is one of the most common causes of cardiovascular death, accounting for up to 50% of all cardiovascular deaths. A number of trials have investigated the association between atrial fibrillation and other heart diseases, including sudden cardiac death. Atrial fibrillation is increasing in prevalence and incidence in the population and is associated with higher morbidity and mortality in patients. The pathophysiological mechanisms in atrial fibrillation are very complex and are linked to a number of other diseases. With these diseases they may share a common background and may interact together. A higher incidence of atrial fibrillation is described especially in patients with coronary artery disease, heart failure, and arterial hypertension. Increased mortality or higher incidence of ventricular arrhythmias, including ventricular fibrillation, has been described in studies in ICD carriers, but also in the general population, where atrial fibrillation has been shown to be an independent risk factor associated with up to a 3-fold increased risk of AF. This paper want to provide a comprehensive picture of the relationship between atrial fibrillation and sudden cardiac death. It provides information...
Evolutionary dynamics of the genus Hemidactylusekkonidae) in space and time
Janák, Vojtěch ; Šmíd, Jiří (advisor) ; Rehák, Ivan (referee)
Hemidactylus is one of the most succesful groups within the infraorder Gekkota of squamate reptiles. With more than 180 species it represents the second most species-rich gekkotan genus. In last decades it has been the subject of a rather intensive research, which provided great insight into it's phylogeny, inner structure, range, biogeography and taxonomy. The number of described species has more than doubled in the same timespan. Despite this increase of knowledge as well as it's evolutionary success, which make the Hemidactylus genus a good model for study of diversification and evolution, there has been no in depth study conducted regarding these topics. This thesis constitutes an attempt at such a study of the phylogeny and evolution of the genus, it's history, dispersal and diversification dynamics, based on more complete species sampling than has been used in any study so far.
Evolution of vipers and the role of key innovations in their diversification
Waldhauser, Vojtěch ; Šmíd, Jiří (advisor) ; Gvoždík, Václav (referee)
The family Viperidae consists of 36 genera, containing more than 350 species in total. The family is distributed throughout Africa and most of Eurasia, however the greatest diversity is located in North and South America, where more than 40 % of the viper species can be found. The family is thus missing only in Australia, New Guinea, Madagascar, New Zealand and a number of other islands and archipelagos. As with most reptiles, they are also almost completely absent from polar regions, with the exception of Vipera berus, the only snake that has ventured north of the Arctic Circle. Their relative evolutionary success is attributed to many so called "key innovations", which include solenoglyphous dentition, viviparity of many genera or heat- sensing pits in the subfamily Crotalinae. Vipers are not only interesting because of their evolutionary history, but they are also subject of important medical studies regarding their venom and toxicity. WHO estimates that around 100,000 people worldwide may die from snake bites each year. This thesis presents a summary of our current knowledge of the evolutionary history of this family, including phylogeny and biogeography, and contemplates the mechanisms behind its amazing diversity.
Systematics, Phylogeny and Biogeography of the gecko genus Hemidactylus (Reptilia, Gekkonidae) in Arabia and the Near East.
Šmíd, Jiří ; Moravec, Jiří (advisor) ; Kotlík, Petr (referee) ; Rehák, Ivan (referee)
(in English) Until relatively recently, the gecko genus Hemidactylus was considered to contain only several hard-to-distinguish species in the eastern Mediterranean and the Arabian Peninsula. This was mostly given by the apparent morphological uniformity of the geckos in combination with their often synanthropic lifestyle, which facilitated the dispersal of some of the species over large ranges. However, our understanding of the diversity of the genus was about to change with the onset of molecular phylogenetic methods that became extensively available and routinely applied to tackle the questions of systematics and phylogeny of all kinds of organisms. This thesis focuses on resolving the phylogeny, systematics, and biogeography of the Arabian Hemidactylus. Using an unprecedented sampling of over 500 samples of more than 40 Hemidactylus species from the eastern Mediterranean, Arabian Peninsula, Socotra, North and East Africa and Iran and sequencing up to six genes (two mitochondrial - 12S rRNA, cyt b; four nuclear - cmos, mc1r, rag1, rag2) I reconstructed the time-calibrated phylogeny of the arid clade of Hemidactylus, inferred its complex biogeographical history in the region, and detected seven potentially new species. The results of the biogeographic analyses indicate that the current...
Climatic determinates of elevation ranges in tropical vertebrates
Vobořilová, Kateřina ; Hořák, David (advisor) ; Šmíd, Jiří (referee)
Tropical regions are amongst the most diverse ecosystems on Earth. The significant species richness of these ecosystems is evident in the number of vertebrate species due to their distribution along altitudinal gradients. The distribution of vertebrates throughout altitudinal gradients is a natural phenomenon by which vertebrates respond to diverse abiotic conditions. Together with the geographic distribution of mountains, biotic influences, thermal physiology of individual vertebrate groups or climatic changes, these abiotic conditions create specific conditions for vertebrates. All of these factors may contribute to the spread of vertebrates to lower or higher altitudes. They may also influence altitudinal migration, depending on the adaptation of individual vertebrate species. In this thesis I focused on how individual abiotic determinants such as temperature, precipitation and air humidity, as well as climatic changes, can positively or negatively influence the distribution ranges of four vertebrate groups along elevational gradients of tropical mountains. Keywords: temperature, precipitation, cloudiness, tropics, elevation, geographical distribution, species richness
Systermatics and biogeography of the genus Platyceps with special emphasis on the Middle Eastern species
Velenská, Doubravka ; Šmíd, Jiří (advisor) ; Rehák, Ivan (referee)
The colubrids genus Platyceps has been included in several phylogenetic studies of the family Colubridae, however the phylogenetic relationships between its species still remain unresolved. The major problem is an insufficient coverage of species in genetic analyses. In this study, I analyse 90 specimens of fourteen Platyceps species to shed more light on the evolutionary history of the genus. Some of the species have never been included in such a genetic analysis before. The phylogeny is based on a combination of four mitochondrial (12S rRNA, cytb, COI, ND4) and two nuclear (cmos, NT3) markers. My results confirm the genus as monophyletic and divide it in to three major clades - the Indian clade (P. bholanathi, P. gracilis, P. ladacensis, P. ventromaculatus a P. sp_central_asia), the West Asian clade (P. karelini, P. rogersi, P. saharicus a P. rhodorachis) and the Dispersive clade (P. plinii, P. josephi, P. florulentus, P. taylori, P. najadum, P. collaris, P. elegantissimus, P. manseri, P. sinai, P. variabilis). According to the results, the phylogenetic positions of several species differ considerably compared to previously published studies. The species Platyceps thomasi appears to be just a colour morph variation of Platyceps variabilis. Platyceps variabilis manseri, on the other hand, emerges...
Phylogeography of the Bunopus geckos (Squamata, Gekkonidae) in the Arabian Peninsula
Pola, Lukáš ; Šmíd, Jiří (advisor) ; Rehák, Ivan (referee)
The Arabian Peninsula represents a bridge between three continents and two major zoogeographic regions, the Palearctic and Afrotropical (Ethiopian). It is well known for its richness and endemicity not only among geckos, but among squamate reptiles in general. Besides impressive endemic species located in the mountains, there are some, widely distributed across the entire Arabian Peninsula (pan-arabian distribution) and in terms of research they remain neglected. Among Arabian geckos, the genus Bunopus are an excellent example, whose systematics and taxonomy are quite problematic, albeit they are distributed across the entire peninsula. In order to answer the question of possible cryptic diversity of these geckos in the Arabian Peninsula, phylogenetic position of more than 80 samples covering the vast part of their distribution range has been reconstructed based on two mitochondrial (12S rRNA and COI) and two nuclear markers (RAG2 and c-mos). Haplotype networks were reconstructed from nuclear markers in order to show genealogical relationships. Results of the phylogenetic analyses presented herein show that cryptic diversity in the Arabian Peninsula is smaller in comparison to the one that was uncovered in the Iranian Plateau. Almost entire Arabian Peninsula is inhabited by two lineages only, which...

National Repository of Grey Literature : 25 records found   1 - 10nextend  jump to record:
See also: similar author names
2 Smid, J.
18 ŠMÍD, Jan
3 ŠMÍD, Jindřich
18 Šmid, Jan
14 Šmíd, Jakub
18 Šmíd, Jan
1 Šmíd, Jaromír
2 Šmíd, Jaroslav
3 Šmíd, Jindřich
4 Šmíd, Josef
Interested in being notified about new results for this query?
Subscribe to the RSS feed.