Near-critical fluctuations and cytoskeleton-assisted phase separation lead to subdiffusion in cell membranes

We address the relationship between membrane microheterogeneity and anomalous subdiffusion in cell membranes by carrying out Monte Carlo simulations of two-component lipid membranes. We find that near-critical fluctuations in the membrane lead to transient subdiffusion, while membrane-cytoskeleton interaction strongly affects phase separation, enhances subdiffusion, and eventually leads to hop diffusion of lipids. Thus, we present a minimum realistic model for membrane rafts showing the features of both microscopic phase separation and subdiffusion.Comment: 21 pages, 5 figures; Supporting Material 5 pages, 1 figure, 1 tabl

Phase separation and near-critical fluctuations in two-component lipid membranes: Monte Carlo simulations on experimentally relevant scales

By means of lattice-based Monte Carlo simulations, we address properties of two-component lipid membranes on the experimentally relevant spatial scales of order of a micrometer and time intervals of order of a second, using DMPC/DSPC lipid mixtures as a model system. Our large-scale simulations allowed us to obtain important results previously not reported in simulation studies of lipid membranes. We find that, within a certain range of lipid compositions, the phase transition from the fluid phase to the fluid-gel phase coexistence proceeds via near-critical fluctuations, while for other lipid compositions this phase transition has a quasi-abrupt character. In the presence of near-critical fluctuations, transient subdiffusion of lipid molecules is observed. These features of the system are stable with respect to perturbations in lipid interaction parameters used in our simulations. The line tension characterizing lipid domains in the fluid-gel coexistence region is found to be in the pN range. When approaching the critical point, the line tension, the inverse correlation length of fluid-gel spatial fluctuations, and the corresponding inverse order parameter susceptibility of the membrane vanish. All these results are in agreement with recent experimental findings for model lipid membranes. Our analysis of the domain coarsening dynamics after an abrupt quench of the membrane to the fluid-gel coexistence region reveals that lateral diffusion of lipids plays an important role in the fluid-gel phase separation process.Comment: 45 pages, 15 figure

Nonlinear symmetry breaking of Aharonov-Bohm cages

We study the influence of mean field cubic nonlinearity on Aharonov-Bohm caging in a diamond lattice with synthetic magnetic flux. For sufficiently weak nonlinearities the Aharonov-Bohm caging persists as periodic nonlinear breathing dynamics. Above a critical nonlinearity, symmetry breaking induces a sharp transition in the dynamics and enables stronger wavepacket spreading. This transition is distinct from other flatband networks, where continuous spreading is induced by effective nonlinear hopping or resonances with delocalized modes, and is in contrast to the quantum limit, where two-particle hopping enables arbitrarily large spreading. This nonlinear symmetry breaking transition is readily observable in femtosecond laser-written waveguide arrays.Comment: 6 pages, 5 figure

Parallel Load Balancing on Constrained Client-Server Topologies

We study parallel \emph{Load Balancing} protocols for a client-server distributed model defined as follows. There is a set \sC of $n$ clients and a set \sS of $n$ servers where each client has (at most) a constant number $d \geq 1$ of requests that must be assigned to some server. The client set and the server one are connected to each other via a fixed bipartite graph: the requests of client $v$ can only be sent to the servers in its neighborhood $N(v)$. The goal is to assign every client request so as to minimize the maximum load of the servers. In this setting, efficient parallel protocols are available only for dense topolgies. In particular, a simple symmetric, non-adaptive protocol achieving constant maximum load has been recently introduced by Becchetti et al \cite{BCNPT18} for regular dense bipartite graphs. The parallel completion time is \bigO(\log n) and the overall work is \bigO(n), w.h.p. Motivated by proximity constraints arising in some client-server systems, we devise a simple variant of Becchetti et al's protocol \cite{BCNPT18} and we analyse it over almost-regular bipartite graphs where nodes may have neighborhoods of small size. In detail, we prove that, w.h.p., this new version has a cost equivalent to that of Becchetti et al's protocol (in terms of maximum load, completion time, and work complexity, respectively) on every almost-regular bipartite graph with degree $\Omega(\log^2n)$. Our analysis significantly departs from that in \cite{BCNPT18} for the original protocol and requires to cope with non-trivial stochastic-dependence issues on the random choices of the algorithmic process which are due to the worst-case, sparse topology of the underlying graph

Ubiquitination in the UV-induced DNA Damage Response: from proteomics to patient

__Abstract__ The integrity of DNA is continuously challenged by genotoxic agents from both internal and external origin that severely hamper vital DNA-dependent processes as genome duplication by replication and reading of the genetic code by transcription. The adverse effects of DNA damage are counteracted by a complex network of genome defence processes, referred to as the DNA damage response (DDR), which consists of different dedicated DNA repair systems and signalling pathways. Nucleotide excision repair (NER) is the main DNA repair process in mammalian cells that removes UV-induced DNA lesions. Protein ubiquitination has emerged as a key regulatory mechanism for this pathway. However, how the entire UV-light induced DDR (UV-DDR) is controlled via ubiquitination remains largely unknown. The aim of the research described in this thesis is to better understand the ubiquitin-mediated regulation of the UV-DDR. To identify new ubiquitin modifications and proteins not previously known to be involved within the UV-DDR on a proteome-wide scale mass spectrometry (MS) was used. To provide the necessary background Chapter 1 summarizes the current knowledge on DDR, ubiquitination and MS-based methods

Impact of Congenital Heart Disease at Adulthood

Since the first surgical techniques for patients with congenital heart disease (ConHD) became available some 55 years ago, virtually every area of patient care has evolved substantially. These improvements lead to an increased survival for patients with ConHD, with over 90% of infants reaching adulthood. This increased survival lead to a shift of focus in that congenital heart disease at adult age nowadays is considered a chronic disease. Therefore, current research does not only focus on survival, but also on the quality of life of these patients. The term quality of life is broad and encompasses many dimensions of life, including – but not limited to – living conditions, wealth and employment, physical and mental health, education, leisure time, psychosocial functioning, lifestyle and social adaptation. In order to investigate the impact of living with a congenital heart defect at adulthood, the aims of this thesis were threefold; 1) To investigate the impact on biographical characteristics 2) To investigate the impact on psychological aspects 3) To investigate the impact on medical aspect

Influence of the lattice topography on a three-dimensional, controllable Brownian motor

We study the influence of the lattice topography and the coupling between motion in different directions, for a three-dimensional Brownian motor based on cold atoms in a double optical lattice. Due to controllable relative spatial phases between the lattices, our Brownian motor can induce drifts in arbitrary directions. Since the lattices couple the different directions, the relation between the phase shifts and the directionality of the induced drift is non trivial. Here is therefore this relation investigated experimentally by systematically varying the relative spatial phase in two dimensions, while monitoring the vertically induced drift and the temperature. A relative spatial phase range of 2pi x 2pi is covered. We show that a drift, controllable both in speed and direction, can be achieved, by varying the phase both parallel and perpendicular to the direction of the measured induced drift. The experimental results are qualitatively reproduced by numerical simulations of a simplified, classical model of the system

“So, it’s quite a big part that goes missing if it, like, wouldn’t exist”:English teachers’ thoughts and experiences on technology in language teaching

Abstract. Technology has become a crucial part of many aspects of our daily life, and a similar effect is seen with technology in teaching. The aim of this study is to find out what English teachers’ thoughts and experiences are on technology in teaching English to middle schoolers. This is achieved with a qualitative method: interviewing two recently graduated English teachers and conducting an inductive thematic analysis on the obtained data. The findings are then discussed in the view of the theoretical background and previous research, which include the socio-cultural learning theory, action-based teaching, the Finnish national core curriculum, and various studies related to technology in teaching. The different ways to use technology in teaching, the benefits and challenges of it, and how and why technology should be used are covered in the review of previous research. The findings indicate that technology is a crucial part of language teaching in Finnish middle schools. Technological tools (e.g., the Internet and laptops) are used by teachers whilst planning the lessons and during them. Much of the teaching material is nowadays in electronic format (e.g., electronic books, videos, and interactive activities), and technology is used in ways that brings authenticity, meaningfulness, and joy to learning English. Especially the activation and motivation of learners is highlighted in the use of technology (e.g., in games and information retrieval exercises). However, the teachers recognise challenges too (e.g., practical aspects and the effects of technology on learners). Even though the learners’ exposure to English can have some benefits (e.g., to their vocabulary), the generous use of technology in free time has negative effects too (e.g., challenges related to learning and behaviour). Collegiality is a key part of searching, sharing, and storing ideas and materials, and the teachers have found technology and its different platforms (e.g., Instagram accounts, Facebook groups, and OneDrive) to be helpful in doing so. The teachers have a will to improve their technology use in their teaching and be responsible of that learning. The findings demonstrate the importance of technology in English teaching today. Technology is viewed as something that adds to the teaching and is a crucial tool in the teacher’s job. Teachers understand the benefits and challenges related to the use of technology. In conclusion, the implications of technology are diverse and affect greatly the language teaching and learning experience from the point of view of both the teacher and the learner.”Että se niinku on aika iso pala siitä pois, jos sitä ei niinku olis” : englanninopettajien ajatukset ja kokemukset liittyen teknologiaan kielen opetuksessa. Tiivistelmä. Teknologiasta on tullut keskeinen osa meidän päivittäistä elämäämme ja samanlainen vaikutus näkyy teknologian opetuskäytössä. Tämän tutkielman tarkoitus on selvittää, millaisia ajatuksia ja kokemuksia englanninopettajilla on liittyen teknologiaan englannin opetuksessa yläkoulussa. Tähän kysymykseen vastataan laadullisen tutkimuksen keinoin: haastattelemalla kahta hiljattain valmistunutta englanninopettajaa ja suorittamalla induktiivinen temaattinen analyysi kerätylle aineistolle. Tuloksia käsitellään peilaten teoreettiseen taustaan ja aiempiin tutkimuksiin, jotka sisältävät sosiokulttuurisen oppimisteorian, toiminnallisen opettamisen, perusopetuksen opetussuunnitelman sekä useita tutkimuksia liittyen teknologian hyödyntämiseen opetuksessa. Aiempien tutkimusten katsauksessa käydään läpi erilaisia tapoja käyttää teknologiaa opetuksessa, sen hyötyjä ja haasteita sekä miten ja miksi teknologiaa tulisi hyödyntää. Tulokset osoittavat, että teknologia on keskeinen osa kielenopettamista suomalaisessa yläkoulussa. Opettajat käyttävät teknologisia välineitä (esim. internetiä ja kannettavia) niin oppituntien aikana kuin niitä suunnitellessaan. Suuri osa opetusmateriaalista on nykyään elektronisessa muodossa (esim. sähköiset kirjat, videot ja interaktiiviset aktiviteetit), ja teknologiaa käytetään siten, että se tuo autenttisuutta, merkityksellisyyttä ja iloa englannin oppimiseen. Erityisesti oppijoiden aktivointia ja motivointia korostetaan teknologian hyödyntämisessä (esim. pelit ja tiedonhakutehtävät). Opettajat kuitenkin tunnistavat myös haasteita (esim. käytännön tekijöitä ja teknologian vaikutukset oppijoihin). Vaikka oppijoiden altistuksessa englannille on joitakin hyötyjä (esim. sanavarastoon), teknologian runsas käyttö vapaa-ajalla vaikuttaa myös negatiivisesti (esim. haasteita oppimisessa ja käytöksessä). Yhteisöllisyys on avainasemassa ideoiden ja materiaalien etsimisessä, jakamisessa ja säilömisessä, ja opettajat ovatkin todenneet teknologian ja sen eri alustojen (esim. Instagram-tilit, Facebook-ryhmät ja OneDrive) olevan siinä hyödyksi. Opettajilla löytyy tahtoa ja kiinnostusta kehittyä teknologian hyödyntämisessä opetuksessaan ja olla vastuussa tästä oppimisesta. Nämä tulokset osoittavat teknologian tärkeyden englannin opetuksessa tänä päivänä. Teknologia koetaan asiana, joka tuo lisää opetukseen ja on välttämätön työkalu opettajan työssä. Opettajat ymmärtävät teknologian käytön hyödyt ja haitat. Tutkimuksen johtopäätöksenä on, että teknologian vaikutukset ovat moninaiset ja ne vaikuttavat suuresti kielen opettamisen ja oppimisen kokemukseen sekä opettajan että oppijan näkökulmasta

Future English teachers’ perspectives on the impact of motivation on learning a foreign language

Abstract. This thesis examines the impact of motivation to the learning process and what the teacher can do to affect the motivation levels of their students. The research is done with qualitative methods using semi-structured interviews. English teacher students were interviewed on how they view the impact of motivation in language learning and what they think the teacher can do to motivate their students. The interviews were recorded and then transcribed. The data was analysed using an inductive thematic analysis. The analysis indicates that the participants recognised the importance of motivation in language learning. The teacher can have a positive or negative effect to the motivation levels of the students. The different aspects that can influence motivation that came up in the interviews and are discussed in this research paper are the teacher’s personality and attitude, the activities during the lessons and the role of the students.Tiivistelmä. Tämä opinnäytetyö tarkastelee motivaation vaikutusta oppimisprosessiin ja sitä, miten opettaja voi vaikuttaa oppilaidensa motivaatiotasoon. Tutkimuksessa käytettiin laadullista tutkimusmenetelmää teemahaastattelujen muodossa. Englannin opettajaopiskelijoita haastateltiin siitä, miten he kokevat motivaation vaikuttavan kielen oppimiseen ja, miten he ajattelevat opettajan voivan parantaa oppilaiden motivaatiota. Haastattelut nauhoitettiin ja sittemmin litteroitiin. Data analysoitiin käyttämällä induktiivista temaattista analyysiä. Analyysi osoittaa, että osallistujat tunnistavat motivaation tärkeyden kielen oppimisessa. Opettajalla voi olla joko positiivinen tai negatiivinen vaikutus oppilaiden motivaatiotasoihin. Opettajan persoonallisuus ja suhtautuminen, oppituntien aktiviteetit sekä oppilaan rooli ovat eri asioita, jotka voivat vaikuttaa motivaatioon ja tulivat ilmi haastatteluissa. Nämä ovat asioita, joita tarkastellaan tässä tutkimuksessa