Modelling of wave climate and sediment transport patterns at a tideless embayed beach, Pirita Beach, Estonia

Nearshore sand transport patterns along the tideless, embayed Pirita beach, Tallinn, Estonia, have been investigated utilizing high-resolution modelling of wave processes combined with bathymetric surveys and sediment textural analyses of the nearshore sea floor. Textural analysis showed the mean grain size is about 0.12 mm. Fine sand (0.063–0.125 mm) accounts for about 77% of the sediments. Coarser-grained sand (0.28 mm) dominates along the waterline. Based upon the spatial distribution of the mean grain size and basic features of the local wave activity, properties of the Dean Equilibrium Beach Profile were determined. Alongshore sediment transport was calculated based upon a long-term time series of wave properties along the beach, and the CERC formula applied to about 500 m long beach sectors. The time series of wave fields and the properties of the local wave climate were modelled using a triple nested WAM wave model with an extended spectral range for short waves. The model is forced by open sea wind data from Kalbådagrund for the years 1981–2002. Results indicate that typical closure depth at Pirita is 2.5 m. The width and mean slope of the equilibrium profile are 250 m and 1:100, respectively. Southward transport dominates in the northern sections of the beach whereas no prevailing transport direction exists in the southern sections. This pattern has several nontrivial implications for the planning of beach protection activities

Perception of negotiation partner: cultural differences from perspective of estonians

Negotiations are a means for entrepreneurial communication and the manner how participants in negotiations treat each other is very much influenced by their cultural background. Cultural background pro¬vides individuals an understanding of their partner’s role from various perspectives. Several cultural orientations have been proposed by different authors to measure cultures. Cultural orientation is considered a relative phenomenon and thus the way other cultures are perceived depends largely on the perceiver. Estonia is a small country which was ruled by various powers but Russian and German impact is mentioned the most often. Both of these countries also play an important role in Estonia’s economy and hence it is interesting and valuable to gain better understanding of how Estonians perceive them in the framework of entrepreneurial communication. The aim of the study is to draw some implications for entrepreneurs by way of studying Estonians’ views on Germans’ and Russians’ negotiation behavior. The study was based on the framework of Hofstede’s cultural dimensions using qualitative research method. The findings, along with other issues, bring up three aspects for entrepreneurs to consider when dealing with international negotiations. Limited experience and the perception of differences may lead to generation of stereotypes among entrepreneurs. Therefore, education and thorough investigation would be beneficial for acquiring efficient negotiation behavior.negotiations; entrepreneurship; national culture; Hofstede’s dimensions; perception of partner.

RIC8A roll hiire närvisüsteemis ja selle arengus

Väitekirja elektrooniline versioon ei sisalda publikatsiooneKesknärvisüsteemi ja perifeerse närvisüsteemi korrektne toimimine on ülioluline organismi täisväärtusliku elu tagamiseks. Seetõttu on närvisüsteemi arengus rangelt kontrollitud ja reguleeritud nii neuraalsete eellasrakkude ja neuronite teke, kui ka korrektne paigutumine ja võrgustike loomine. Neid protsesse koordineerivad mitmed signaalirajad, millest G-valkude (guaniin-nukleotiidi siduvad valgud) poolt vahendatud signaaliülekanne rakuvälise ja rakusisese keskkonna vahel on üks levinumaid mehhanisme närvisüsteemis. G-valkude aktiveerimisel osalevad nii G-valguga seonduvad retseptorid kui ka mitmed rakusisesed valgud, mis mõjutavad G-valkude aktiivsust retseptorist sõltumatult. Näiteks RIC8A, mis toimib G-valkude nukleotiidivahetusfaktorina ja tšaperonina. Imetajates on RIC8A avaldunud nii arenevas kui täiskasvanud närvisüsteemis osaledes tunnetuslike, õppimis- ning tajufunktsioonide kujunemisel. Käesoleva doktoritöö eesmärgiks oli uurida RIC8A rolli hiire närvisüsteemis ja selle arengus. RIC8A puudumine hiire kesk- ja perifeerse närvisüsteemi rakkudest põhjustab neuro-muskulaarset fenotüüpi, mida iseloomustavad lihaste atrofeerumine, motoorika-, tasakaalu- ja koordinatsiooni häired, tõmblused ning sünnijärgne suremus. Ric8A puudulikel hiirtel esinevad kõrvalekalded suurajukoore arengus (nt rakujagunemiste ja neuraalse migratsiooni häired, ajuvatsakeste laienemine, defektne kortikaalne basaalmembraan) ning südame ja silma arengus. Lisaks katsed RIC8A defitsiitsete rakkudega näitasid, et RIC8A on oluline β1-integriini vahendatud tsütoskeleti organiseerimisel ja rakkude migratsioonil. Kirjeldatud defektid on iseloomulikud kaasasündinud lihasdüstroofiatele (Fukuyama lihasdüstroofia, Walker-Warburgi sündroom ja lihase-silma-aju haigus). Seega, häired RIC8A funktsioonis koostöös G-valkude ja β1-integriinide vahendatud signalisatsiooniga võib olla seotud nende haiguste kujunemiselCorrect functioning of central- and peripheral nervous system is essential for normal functioning of the body. Therefore, it is fundamental to control the spatio-temporal development of neural precursor cell division into neurons and their final positioning where they can form functional network between each other. These processes are coordinated by different signalling pathways, where the G-protein mediated signal transduction is one of the prominent mechanism in cell signalling cascade. The activation of G proteins are accomplished via transmembrane G protein coupled receptors or via accessory proteins that influence G proteins receptor-independently. For example, RIC8A affects G protein activity as a guanine nucleotide exchange factor or as a chaperone. In mammals, RIC8A is expressed in the development of the nervous system and plays a role in the regulation of behavior, memory and learning in adults. Current thesis is focused on the role of RIC8A in the nervous system and its development. Ablation of RIC8A in central- and peripheral nervous system causes defects in neuromuscular signalling which is manifested by muscle atrophy and impairment of movements, occasional tremors and lethality after birth. Ric8A deficient mice also display malformations in the development of the cerebral cortex (e.g defects in cell division and cell migration, which affect cortical size and lamination, enlargement of the ventricles and defects in the integrity of cortical basement membrane) and in heart and eye development. In addition, studies on the RIC8A deficient cells showed that RIC8A is crucial for the β1-integrin mediated organisation of cytoskeleton and cell migration. These defects are characteristic to the congenital muscular dystrophies (Fukuyama congenital muscular dystropy, Walker Warbur g syndrome and Muscle-Eye-Brain disease) and that defects in RIC8A functioning in concert with G-protein and β1-integrin mediated signalling may be the cause of these diseases

Mustlaik-apollo [Parnassius mnemosyne (L.)] levik ja elupaiga eelistused Eestis

According to the European Red List of Butterflies, 31% of the European butterflies have declining populations. One of the specialist butterfly species that has declining population in whole Europe and that has been interest of many scientists is the Clouded Apollo [(Parnassius mnemosyne (L.)]. The results of the theses show that the abundance and distribution area of Clouded Apollo have increased in recent years in Estonia that is the opposite process than in the rest of Europe. Since 1984, there is new population of Clouded Apollo in South Estonia that has increased its abundance and distribution area. The reason for this seems to be the appearance of high quality habitats with ideal landscape structure for the butterfly. The most preferred habitat of Clouded Apollo is the semi-natural meadow with the strip of alders on the banks of rivers. The riparian meadows with strip of alders have good conditions for the main requirements of the Clouded Apollo: nectar sources for the imago, places for mating and breeding, shelter for the imago, food plant for the larvae. The places of appearance of Clouded Apollo are in correspondence with the distribution area of the larvaeal food plant – Corydalis solida. The landscape structure plays important role in the distribution of the butterfly. Rivers create natural ecological network, providing suitable habitats, migration corridors, stepping stones through the biotopes that are barriers for the butterfly. The Clouded Apollo is the species that clearly benefits from corridors in the landscape that can increase their movement ability. The political and socio-economic changes have led to the large changes of agricultural practises and land use during last century. The semi-natural meadows are one of the most vulnerable biotopes in Estonia. As the main habitat for Clouded Apollo the attention must be paid to avoid decrease of these valuable habitats. The management of the Clouded Apollo should consider the preservation of the high quality habitats and their proper density and connectivity in the landscape to ensure preservation and enduring distribution of this protected butterfly.Euroopa liblikate punase nimestiku andmetel on 31% Euroopa liblikaliikide arvukus kahanemas. Rohumaa spetsialisti mustlaik-apollo (Parnassius mnemosyne) levik ja arvukus on vähenenud kogu Euroopas. Antud doktoritöö tulemused näitavad, et Eestis on mustlaik-apollo arvukus ja levik viimaste kümnendite jooksul suurenenud, mis on vastupidine suundumus kogu ülejäänud Euroopas toimuvale. Alates 1984. aastast on Lõuna-Eestis uus mustlaik-apollo populatsioon, mis suurendab jõudsalt oma arvukust ja levikuala. Selle põhjuseks on kõrge väärtusega elupaikade ja liblika jaoks sobiva maastiku struktuuri olemasolu. Mustlaik-apollo eelistatumad elupaigad on pool-looduslikud niidud, mis asuvad jõgede kallastel ja mille ääres on puuderiba, enamasti lepariba. Jõgedeäärsed leparibaga niidud vastavad kõikidele peamistele mustlaik-apollo elupaiganõudlustele: on olemas nektarivarud, avatud paaritumis- ja sigimispaigad, rööviku toidutaim ja tuulevari. Eestis mängib mustlaik-apollo levikus olulist rolli ka maastiku struktuur. Jõed moodustavad loodusliku rohevõrgustiku, tagades liblikale eluks sobilikud elupaigad, levikukoridorid ja astmelauad läbi nende biotoopide, mis on talle levikubarjääriks. Mustlaik-apollo levikualad on vastavuses monofaagist rööviku toidutaime hariliku lõokannuse (Corydalis solida) kasvukohtadega. Mustlaik-apollole elupaigaks sobivad pool-looduslikud niidud on väga tundlikud hooldamata jätmise suhtes. Viimase sajandi jooksul toimunud poliitilised ja sotsiaal-majanduslikud muutused on viinud suurte muutusteni ka Eesti põllumajanduses ja maakasutuses, vähenenud on traditsioonilise põllumajanduse osakaal ja paljud pool-looduslikud niidud on maha jäetud. Olles mustlaik-apollo peamisteks elupaikadeks, tuleks vältida nende väärtuslike elupaigatüüpide kinnikasvamist ja kadumist, et tagada haruldase kaitsealuse liblikaliigi säilimine ja edasine levik Eestis

Contact tracing apps in Europe: When one is better than many. Bertelsmman Stiftung Policy Position June 2020.

One of the issues brought forth by the COVID-19 crisis is the need to track the infection chains in order to stop the disease from spreading. One of the simplest ways this can be done is via a smartphone app. However, this can bring about several privacy issues. Furthermore, unless a common protocol is taken up all over Europe allowing apps from different member states to be able to seamlessly communicate with each other, the discrepancies would render the national apps ineffective. The member states need to de- cide on a single app protocol throughout Europe and the European Com- mission should strongly back its uptake

Keelespetsiifiliste stiimulite töötlus erinevatel keelegruppidel: EEG uuring

Two almost identical EEG experiments were conducted with about one month between them to examine how the brain processes language specific stimuli among Estonian (n =15, aged 19-27 years) and Russian (n = 15, aged 18-27 years) native speakers. The used stimuli were based on Estonian quantity changes, which are not structurally common for Russian speakers. Two different linguistic stimulus sets (SADA, SAGI) and one physically similar tone stimulus set were used, stimuli differed from each other by duration and tonal change. During the EEG recording, participants had to watch a silent movie while auditory language stimuli were presented in an MMN experimental paradigm to their headphones. An additional speech intelligibility test was conducted on both times and self-reported questionnaire had to be filled before the testing. The tone stimulus elicited a more persistent MMN wave with larger amplitude in both language group, linguistic stimuli elicited a more pronounced MMN response among Estonian native speakers. The study provided a slight support to previous findings, as the Estonians used both durational and pitch cue to discriminate quantities. Only few used conditions elicited MMN among Russian native speakers with no complete clarity if the activity was caused by durational or pitch cue (or both). No consistent lateralization effect was found nor relationships with possible background factors (language abilities, musicality, language experience and time spent in Estonian language environment for Russian native speakers)