Effects of recreational activity on Acorn Barnacle (Tetraclita squamosa rufotincta) in the Red Sea

Environmental recreation is a fast growing industry. However, in many cases the consequences for the environment are ignored. Eilat is just such a case wherein tourism is the mainstay of the city and the Red Sea is the main attraction. Most areas are developed specifically for enhancing tourism and one of the most benign of creatures, that sits permanently on rocks and seashores, is trodden upon regularly is the Acorn Barnacle (Tetraclita squamosa rufotincta). We surveyed 10 sites with the same area for the number of barnacles that were live, dead or deserted. We compared between areas frequented by recreationists, and from which, they were denied access. We found a significantly greater number of individuals, live barnacles, and fewer deserted barnacles in the restricted areas. We conclude that the Acorn Barnacles in the undisturbed areas had significantly greater probability of survival and longevity compared to those exposed to anthropogenic activity

Numerical Simulations of Dynamics Behaviour of the Action Potential of the Human Heart\u27s Conduction System

A proposed model consisting of two coupled van der Pol models is considered as a description of the heart action potential. A system of ordinary differential equations is used to recreate pathological behaviour in the conducting system of the heart such as Wolff-Parkinson-White (WPW) syndrome and the most common tachycardia: atrioventricular nodal reentrant tachycardia (AVNRT). Part of the population has abnormal accessory pathways: fast and slow. These pathways in the atrioventricular node (AV node) are anatomical and functional excipients of supraventricular tachycardia. However, the appearance of two pathways in the AV node may be an excipient of arrhythmia—the WPW syndrome. The difference in the conduction time between these pathways is the most important factor. This is the reason to introduce three types of couplings and delay to our system in order to reproduce different types of the AVNRT. In our research, the result of introducing the feedback loops and couplings entails the creation of waves which can correspond to the re-entry waves which occur in the AVNRT. Our main aim is to study solutions of the equations of the system and to take into consideration the influence of feedback and delays which occur in the pathological modes. The proposed models made it possible to reproduce the most important physiological properties of the discussed pathologies. Since the model is phenomenological, the results are accurate as far as a simple model can describe the potential found in one of the more complex oscillators found in biology

Weak antilocalization in a strained InGaAs/InP quantum well structure

Weak antilocalization (WAL) effect due to the interference corrections to the conductivity has been studied experimentally in a strained InGaAs/InP quantum well structure. From measurements in tilted magnetic filed, it was shown that both weak localization and WAL features depend only on the normal component of the magnetic field for tilt angles less than 84 degrees. Weak antilocalization effect showed non-monotonous dependence on the gate voltage which could not be explained by either Rashba or Dresselhouse mechanisms of the spin-orbit coupling. To describe magnetic field dependence of the conductivity, it was necessary to assume that spin-orbit scattering time depends on the external magnetic field which quenches the spin precession around effective, spin-orbit related, magnetic fields.Comment: Presented at EP2DS 2003 (Nara), to be published in Physica

Road-kills in New Zealand: long-term effects track population changes and reveal colour blindness

Road-kills were recorded at random throughout New Zealand, on 96359 km of roads, avoiding towns and busy motorways, from 1963-2018. Traffic increase from 1.04 m to 4.33 million vehicles during the study had little effect on mortality, even at the greater traffic density in the North Island. Seasonal changes measured on 8435 km (151 trips) between Lower Hutt and Otaki from 1985-2015 showed lowest mortality in winter. Major differences in species identification between two independent observers on the same route, from 2009-2014, resulted from one being red/green colourblind. Possum (Trichosurus vulpecula) numbers dipped briefly in the 1970s, peaked in the 1990s, and have declined since then where there has been widespread poisoning to protect trees, birds, and limit bovine TB. Rabbits (Oryctolagus cuniculus) increased steadily after control was lifted in the 1980s and now dominate the road-kills; the effect of RHD, introduced in 1997, does not register, probably because it causes short-term local oscillations. Hedgehog (Erinaceus europaeus) numbers show no clear trend and, unlike the other species, North and South Island patterns differ; the lower numbers in the South may reflect the cooler climate. Brown hares (Lepus europaeus) remain relatively stable, with a doubling in numbers since the 1980s in parallel with rabbits. The predators, cats (Felis catus) and mustelids (Mustela furo, M.erminea, M. nivalis), followed their prey increase until the 1990s when extensive predator control began; they then declined, although rabbit and rat (Rattus rattus, R. norvegicus) numbers continued to rise. In the 1950-60s, far more live mammals were being seen on and from roads, and adaptations to traffic have evolved. These historical records may be useful to assess future changes in road-kill following the adoption of silent electric cars, driverless vehicles, and public transport

Novitäten im Breslauer Stadttheater: Richard Strauss - Salome (1906), Claudio Monteverdi - L''Orfeo (1913), Ludomir Różycki Eros und Psyche (1917)

Am Anfang des 20. Jahrhunderts zählte das Breslauer Stadttheater, obwohl mit nur einer kleinen Orchester-Besetzung ausgestattet, zu den bemerkenswerten europäischen Opernbühnen. Es war aufgeschlossen für musikalische Novitäten. Als Beweis dafür sind u.a. die Breslauer Premieren Salome (1906) von Richard Strauss, L\''Orfeo (1913) von Claudio Monteverdi und die Uraufführung der Oper Eros und Psyche (1917) von Ludomir Różycki zu nennen

Numerical Analysis of the Coupled Modified van der Pol Equations in a Model of Heart Action

In this paper, a modified van der Pol equations are considered as a description of the heart action. Wide ranges of the model parameters yield interesting qualitative results, e.g. Hopf bifurcation, Bogdanov-Takens bifurcation, transcritical and pitchfork bifurcations but also some stable solutions can be found. The physiological model works in the narrowest range of parameters which allows to obtain a stable behaviour what is important in biological problem. When some kinds of pathologies appear in the heart, it is possible to obtain chaotic behaviour. My aim is to compare the influence of these two types of coupling (unidirectional and bidirectional) on the behaviour of the van der Pol system. The coupling takes place in a system with healthy conductivity, between two nodes: SA and AV, but in some circumstances, a pathological coupling may occur in the heart. The van der Pol oscillator is a type of relaxation oscillator which can be synchronized. In this paper, synchronization properties of such a system are studied as well. For the purpose of a numerical analysis of the system in question, a numerical model was created

Motywacje uczestnictwa w Światowych Dniach Młodzieży w Krakowie i jego wpływ na życie religijno-społeczne uczestników na przykładzie pielgrzymów z Archidiecezji Warmińskiej

W artykule przedstawiono wyniki badań empirycznych przeprowadzonych wśród uczestników Światowych Dni Młodzieży w Krakowie w 2016 r. pochodzących z terenu archidiecezji warmińskiej. Badania dotyczyły motywacji uczestnictwa w wydarzeniu, a także jego późniejszego oddziaływania na biografie uczestników. Spośród wyróżnionych w badaniu ankietowym grup motywacji (religijnych, wspólnotowych oraz ludycznych) największe znaczenie, w opinii respondentów, odgrywały motywacje o charakterze religijnym. Natomiast w wypowiedziach udzielonych w wywiadach akcentowano szczególną ważność doświadczeń o charakterze wspólnotowym. W badaniach – ilościowym oraz jakościowym – wymiar ludyczny odgrywa najmniej istotną rolę, co pozwala przypuszczać, że religijne eventy oddziałują na ludzi młodych nie tyle, jak się często przypuszcza, poprzez komponenty emocjonalno-rozrywkowe, lecz przede wszystkim dostarczając im okazji do autentycznego doświadczenia religijnego i wspólnotowego

Road-kills in New Zealand: long-term effects track population changes and reveal colour blindness

Road-kills were recorded at random throughout New Zealand, on 96359 km of roads, avoiding towns and busy motorways, from 1963-2018. Traffic increase from 1.04 m to 4.33 million vehicles during the study had little effect on mortality, even at the greater traffic density in the North Island. Seasonal changes measured on 8435 km (151 trips) between Lower Hutt and Otaki from 1985-2015 showed lowest mortality in winter. Major differences in species identification between two independent observers on the same route, from 2009-2014, resulted from one being red/green colourblind. Possum (Trichosurus vulpecula) numbers dipped briefly in the 1970s, peaked in the 1990s, and have declined since then where there has been widespread poisoning to protect trees, birds, and limit bovine TB. Rabbits (Oryctolagus cuniculus) increased steadily after control was lifted in the 1980s and now dominate the road-kills; the effect of RHD, introduced in 1997, does not register, probably because it causes short-term local oscillations. Hedgehog (Erinaceus europaeus) numbers show no clear trend and, unlike the other species, North and South Island patterns differ; the lower numbers in the South may reflect the cooler climate. Brown hares (Lepus europaeus) remain relatively stable, with a doubling in numbers since the 1980s in parallel with rabbits. The predators, cats (Felis catus) and mustelids (Mustela furo, M.erminea, M. nivalis), followed their prey increase until the 1990s when extensive predator control began; they then declined, although rabbit and rat (Rattus rattus, R. norvegicus) numbers continued to rise. In the 1950-60s, far more live mammals were being seen on and from roads, and adaptations to traffic have evolved. These historical records may be useful to assess future changes in road-kill following the adoption of silent electric cars, driverless vehicles, and public transport

Soil mites (Acari) of natural areas of a former military training field in Olsztyn (Poland)

Due to restricted public access to military training fields such areas are quite interesting places for conducting faunistic research that would be simply impossible in other terrains. The area examined in the present study was the former military training field in Olsztyn, with the adjacent Lasek Pieczewski and the valley of Skanda Lake. The major aim of the study was to evaluate the current state of the environment in the terrain of the former military training field and the adjacent areas. In this study mites from the suborder Uropodina and cohort Labidostommatina (Acari: Mesostigmata et Prostigmata) were used as a bioindicators. These mites are useful for this purpose because of their specific habitat preferences. The community of mites in the area under scrutiny contained 23 taxa, comparing to 34 species found in whole voivoideship, which is 68% of local species biodiversity. Oodinychus ovalis turned out to be the most numerous species (the specimens of this species constituted almost 38% of the whole community and the frequency per sample was 55%). The other quite numerous species found in the examined area were Janetiella pulchella and Oodinychus karawaiewi, which constituted over 30% of the whole community. Taking into account the number of species and their habitat preferences two most valuable areas were found: southern part of Lasek Pieczewski and Skanda Lake valley. DOI: http://dx.doi.org/10.5281/zenodo.353444