Molecular genetics of the immotile short tail sperm defect

Hedelmättömyyttä aiheuttavan siittiöiden puolihäntävian molekyyligenetiikka Suomalaisissa Yorkshire karjuissa yleistyi 1990-luvun lopulla autosomaalisesti ja resessiivisesti periytyvä hedelmättömyyttä aiheuttava siittiöiden puolihäntävika (ISTS, immotile short tail sperm). Sairaus aiheuttaa normaalia lyhyemmän ja täysin liikkumattoman siittiön hännän muodostuksen. Muita oireita sairailla karjuilla ei ole havaittu ja emakot ovat oireettomia. Tämän tutkimuksen tarkoituksena oli kartoittaa siittiöiden puolihäntävian aiheuttava geenivirhe ja kehittää DNA-testi markkeri- ja geeniavusteiseen valintaan. Koko genomin kartoituksessa vian aiheuttava alue paikannettiin sian kromosomiin 16. Paikannuksen perusteella kahden geenimerkin haplotyyppi kehitettiin käytettäväksi markkeri-avusteisessa valinnassa. Sairauteen kytkeytyneen alueen hienokartoitusta jatkettiin geenitestin kehittämiseksi kantajadiagnostiikkaan. Vertailevalla kartoituksella oireeseen kytkeytynyt alue paikannettiin 2 cM:n alueelle ihmisen kromosomiin viisi (5p13.2). Tällä alueella sijaitsevia geenejä vastaavista sian sekvensseistä löydetyn muuntelun perusteella voitiin tarkentaa sairauteen kytkeytyneitä haplotyyppejä. Haplotyyppien perusteella puolihäntäoireeseen kytkeytynyt alue rajattiin kahdeksan geenin alueelle ihmisen geenikartalla. Alueelle paikannetun kandidaattigeenin (KPL2) sekvensointi paljasti introniin liittyneen liikkuvan DNA-sekvenssin, Line-1 retroposonin. Tämä retroposoni muuttaa geenin silmikointia siten, että sitä edeltävä eksoni jätetään pois tai myös osa introni- ja inserttisekvenssiä liitetään geenin mRNA tuotteeseen. Molemmissa tapauksissa tuloksena on lyhentynyt KPL2 proteiini. Tähän retroposoni-inserttiin perustuva geenitesti on ollut sianjalostajien käytössä vuodesta 2006. KPL2 geenin ilmenemisen tarkastelu sialla ja hiirellä paljasti useita kudosspesifisiä silmikointimuotoja. KPL2 geenin pitkä muoto ilmenee pääasiassa vain kiveksessä, mikä selittää geenivirheen aiheuttamat erityisesti siittiön kehitykseen liittyvät oireet. KPL2 proteiinin ilmeneminen hiiren siittiön hännän kehityksen aikana ja mahdollinen yhteistoiminta IFT20 proteiinin kanssa viittaavat tehtävään proteiinien kuljetuksessa siittiön häntään. Mahdollisen kuljetustehtävän lisäksi KPL2 saattaa toimia myös siittiön hännän rakenneosana, koska se paikannettiin valmiin siittiön hännän keskiosaan. Lisäksi KPL2 proteiini saattaa myös toimia Golgin laitteessa sekä Sertolin solujen ja spermatidien liitoksissa, mutta nämä havainnot kuitenkin vaativat lisätutkimuksia. Tämän tutkimuksen tulokset osoittavat, että KPL2 geeni on tärkeä siittiön hännän kehitykselle ja sen rakennemuutos aiheuttaa siittiöiden puolihäntäoireen suomalaisilla Yorkshire karjuilla. KPL2 proteiinin ilmeneminen ja paikannus siittiön kehityksen aikana antaa viitteitä proteiinin toiminnasta. Koska KPL2 geenisekvenssi on erittäin konservoitunut, nämä tulokset tuovat uutta tietoa kaikkien nisäkkäiden siittiöiden kehitykseen ja urosten hedelmättömyyteen syihin.

Radio Frequency Measurement Method for Detecting Bearing Currents in Induction Motors

Induction motors are widely used in industry, and they are generally considered very reliable. They often have a critical role in industrial processes, and their failure can lead to significant losses as a result of shutdown times. Typical failures of induction motors can be classified into stator, rotor, and bearing failures. One of the reasons for a bearing damage and eventually a bearing failure is bearing currents. Bearing currents in induction motors can be divided into two main categories; classical bearing currents and inverter-induced bearing currents. A bearing damage caused by bearing currents results, for instance, from electrical discharges that take place through the lubricant film between the raceways of the inner and the outer ring and the rolling elements of a bearing. This phenomenon can be considered similar to the one of electrical discharge machining, where material is removed by a series of rapidly recurring electrical arcing discharges between an electrode and a workpiece. This thesis concentrates on bearing currents with a special reference to bearing current detection in induction motors. A bearing current detection method based on radio frequency impulse reception and detection is studied. The thesis describes how a motor can work as a “spark gap” transmitter and discusses a discharge in a bearing as a source of radio frequency impulse. It is shown that a discharge, occurring due to bearing currents, can be detected at a distance of several meters from the motor. The issues of interference, detection, and location techniques are discussed. The applicability of the method is shown with a series of measurements with a specially constructed test motor and an unmodified frequency-converter-driven motor. The radio frequency method studied provides a nonintrusive method to detect harmful bearing currents in the drive system. If bearing current mitigation techniques are applied, their effectiveness can be immediately verified with the proposed method. The method also gives a tool to estimate the harmfulness of the bearing currents by making it possible to detect and locate individual discharges inside the bearings of electric motors.

Shot-noise spectroscopy of energy resolved ballistic currents

We investigate the shot noise of nonequilibrium carriers injected into a ballistic conductor and interacting via long-range Coulomb forces. Coulomb interactions are shown to act as an energy analyzer of the profile of injected electrons by means of the fluctuations of the potential barrier at the emitter contact. We show that the details in the energy profile can be extracted from shot-noise measurements in the Coulomb interaction regime, but cannot be obtained from time-averaged quantities or shot-noise measurements in the absence of interactions.

Microcontroller-based interface circuit for inductive sensors

This work proposes a fully-digital interface circuit for the measurement of inductive sensors using a low-cost microcontroller (µC) and without any intermediate active circuit. Apart from the µC and the sensor, the circuit just requires an external resistor and a reference inductance so that two RL circuits with a high-pass filter (HPF) topology are formed. The µC appropriately excites such RL circuits in order to measure the discharging time of the voltage across each inductance (i.e. sensing and reference) and then it uses such discharging times to estimate the sensor inductance. Experimental tests using a commercial µC show a non-linearity error (NLE) lower than 0.5%FSS (Full-Scale Span) when measuring inductances from 1 mH to 10 mH, and from 10 mH to 100 mH.

Short story

Digitoitu 14. 1. 2009

Poisoning and regeneration of Pt-Pd/WO3-ZrO2 short paraffin isomerization catalysts

WO3-ZrO2 catalysts promoted with Pt and Pd were tested as paraffin isomerization catalysts using n-hexane as model compound. Sulfur and amine poisoning and regeneration tests were used to assess the impact of the addition of Pt and Pd on the deactivation resistance and regenerability. Pt and PtPd catalysts were the most active for n-hexane isomerization. The low activity of the Pd catalyst was attributed to poor Pd metal properties when supported over WO3-ZrO2 and to a decrease of the number of BrQnsted acid sites. PtPd was the only catalyst capable of full regeneration after S poisoning. Amine poisoning completely supressed the isomerization activity and the original activity could only be restored by calcination and reduction.

Laakerikipinöintilaskurin toteuttaminen FPGA- piirillä

FPGA- piirit ovat viime vuosina kehittyneet tehokkaammiksi, mutta samalla niiden hinta on laskenut tasolle, jolloin ne ovat vaihtoehto yhä useampiin sovelluksiin. Kandidaatintyöni aiheena oli suunnitella ja mahdollisesti toteuttaa sulautettu laite, joka laskisi signaalissa esiintyvien pulssien lukumäärää. Sitä käytettäisiin mitattaessa kipinöintiä sähkömoottorin laakeroinnissa. Kipinät havaitaan moottorin ulkopuolelta UHF- antennilla. Antennisignaalista poimittavat pulssit ovat hyvin nopeita, joten digitaaliselta logiikalta vaaditaan myös erityistä nopeutta. Tämän takia laitetta lähdettiin toteuttamaan esimerkiksi mikrokontrollerin sijasta FPGA- piirin avulla. Pulssilaskurin toteutus onnistui suhteellisen vaivattomasti FPGAlla, ja sen toimivuutta käytännössä päästiin testaamaan todellisissa olosuhteissa.

APARATO ELETROQUÍMICO PARA SISTEMA DE AQUISIÇÃO DE DADOS MULTICANAL COM RESOLUÇÃO ESPAÇO-TEMPORAL

Spatiotemporal pattern formation in reaction-transport systems takes place spontaneously when the system is kept far from thermodynamic equilibrium. Targets, reaction fronts, waves, spirals, spots and stripes are some typical examples of selforganized structuring. In electrochemical systems, monitoring spatiotemporal patterns of potential in the solid/liquid interface can be done by the use of equally distributed microprobes located close to the working electrode. However, the physical size of each probe can limit the spatial resolution and alter mass transport properties. In contrast, the direct measurement of discrete electrodes does not suffer from this limitation and allows the accurate manipulation of the spatial coupling through changes in resistors connected to the electric circuit. In this paper, the development of an electrochemical setup for multichannel data acquisition with spatiotemporal resolution is described, especially to monitor low levels of currents usually observed in the electro-oxidation of small organic molecules.

Compliance of crane electrics with electrical safety standards and codes

Master’s thesis focuses on the questions of crane electrics compliance with electrical safety standards. Overview and short comparison of the world’s effective standards in the field is made in order to understand their demands. Basic concepts of a proper electrical circuit design are presented. Characteristics, construction and operation principles of overcurrent protective devices are studied in details. Electrics of the basic crane is designed according to the assumed customer’s demands, compliance with the requirements of the standards is checked. Solutions to achieve better compliance in some issues are proposed. Accent is made on the National Electrical Code (NEC) and standards by Underwriters Laboratories (UL) latests demands. Requirements of the International Electrotechnical Commission (IEC) are also taken into account.

Parallella, dynamiska representationer i gymnasiefysiken : implementering av ett interaktivt datorverktyg i didaktiska situationer och uppfattning av effektivt lärande

The computer is a useful tool in the teaching of upper secondary school physics, and should not have a subordinate role in students' learning process. However, computers and computer-based tools are often not available when they could serve their purpose best in the ongoing teaching. Another problem is the fact that commercially available tools are not usable in the way the teacher wants. The aim of this thesis was to try out a novel teaching scenario in a complicated subject in physics, electrodynamics. The didactic engineering of the thesis consisted of developing a computer-based simulation and training material, implementing the tool in physics teaching and investigating its effectiveness in the learning process. The design-based research method, didactic engineering (Artigue, 1994), which is based on the theoryof didactical situations (Brousseau, 1997), was used as a frame of reference for the design of this type of teaching product. In designing the simulation tool a general spreadsheet program was used. The design was based on parallel, dynamic representations of the physics behind the function of an AC series circuit in both graphical and numerical form. The tool, which was furnished with possibilities to control the representations in an interactive way, was hypothesized to activate the students and promote the effectiveness of their learning. An effect variable was constructed in order to measure the students' and teachers' conceptions of learning effectiveness. The empirical study was twofold. Twelve physics students, who attended a course in electrodynamics in an upper secondary school, participated in a class experiment with the computer-based tool implemented in three modes of didactical situations: practice, concept introduction and assessment. The main goal of the didactical situations was to have students solve problems and study the function of AC series circuits, taking responsibility for theirown learning process. In the teacher study eighteen Swedish speaking physics teachers evaluated the didactic potential of the computer-based tool and the accompanying paper-based material without using them in their physics teaching. Quantitative and qualitative data were collected using questionnaires, observations and interviews. The result of the studies showed that both the group of students and the teachers had generally positive conceptions of learning effectiveness. The students' conceptions were more positive in the practice situation than in the concept introduction situation, a setting that was more explorative. However, it turned out that the students' conceptions were also positive in the more complex assessment situation. This had not been hypothesized. A deeper analysis of data from observations and interviews showed that one of the students in each pair was more active than the other, taking more initiative and more responsibilityfor the student-student and student-computer interaction. These active studentshad strong, positive conceptions of learning effectiveness in each of the threedidactical situations. The group of less active students had a weak but positive conception in the first iv two situations, but a negative conception in the assessment situation, thus corroborating the hypothesis ad hoc. The teacher study revealed that computers were seldom used in physics teaching and that computer programs were in short supply. The use of a computer was considered time-consuming. As long as physics teaching with computer-based tools has to take place in special computer rooms, the use of such tools will remain limited. The affordance is enhanced when the physical dimensions as well as the performance of the computer are optimised. As a consequence, the computer then becomes a real learning tool for each pair of students, smoothly integrated into the ongoing teaching in the same space where teaching normally takes place. With more interactive support from the teacher, the computer-based parallel, dynamic representations will be efficient in promoting the learning process of the students with focus on qualitative reasoning - an often neglected part of the learning process of the students in upper secondary school physics.

The effectiveness of short-term literacy skills intervention on children at risk of reading and writing difficulties in Tanzania : a study of grade one children with dynamic assessment approach

The aim of the study was to create and evaluate an intervention programme for Tanzanian children from a low-income area who are at risk of reading and writing difficulties. The learning difficulties, including reading and writing difficulties, are likely to be behind many of the common school problems in Tanzania, but they are not well understood, and research is needed. The design of the study included an identification and intervention phase with follow-up. A group based dynamic assessment approach was used in identifying children at risk of difficulties in reading and writing. The same approach was used in the intervention. The study was a randomized experiment with one experimental and two control groups. For the experimental and the control groups, a total of 96 (46 girls and 50 boys) children from grade one were screened out of 301 children from two schools in a low income urban area of Dar-es-Salaam. One third of the children, the experimental group, participated in an intensive training programme in literacy skills for five weeks, six hours per week, aimed at promoting reading and writing ability, while the children in the control groups had a mathematics and art programme. Follow-up was performed five months after the intervention. The intervention programme and the tests were based on the Zambian BASAT (Basic Skill Assessment Tool, Ketonen & Mulenga, 2003), but the content was drawn from the Kiswahili school curriculum in Tanzania. The main components of the training and testing programme were the same, only differing in content. The training process was different from traditional training in Tanzanian schools in that principles of teaching and training in dynamic assessment were followed. Feedback was the cornerstone of the training and the focus was on supporting the children in exploring knowledge and strategies in performing the tasks. The experimental group improved significantly more (p = .000) than the control groups during the intervention from pre-test to follow-up (repeated measures ANOVA). No differences between the control groups were noticed. The effect was significant on all the measures: phonological awareness, reading skills, writing skills and overall literacy skills. A transfer effect on school marks in Kiswahili and English was found. Following a discussion of the results, suggestions for further research and adaptation of the programme are presented.

Future prospects of short distance rail based passenger transport in Northern Europe

The worlds’ population is increasing and cities have become more crowded with people and vehicles. Communities in the fringe of metropolitans’ increase the traffic done with private cars, but also increase the need for public transportation. People have typically needs traveling to work located in city centers during the morning time, and return to suburbs in the afternoon or evening. Rail based passenger transport is environmentally friendly transport mode with high capacity to transport large volume of people. Railways have been regulated markets with national incumbent having monopoly position. Opening the market for competition is believed to have a positive effect by increasing the efficiency of the industry. National passenger railway market is opened for competition only in few countries, where as international traffic in EU countries was deregulated in 2010. The objective of this study is to examine the passenger railway market of three North European countries, Sweden, Denmark and Estonia. The interest was also to get an understanding of the current situation and how the deregulation has proceeded. Theory of deregulation is unfolded with literature analyses and empirical part of the study is constructed from two parts. Customer satisfaction survey was chosen as a method to collect real life experiences from the passengers and measure their knowledge of the market situation and possible changes appeared. Interviews of experts from the industry and labor unions give more insights and able better understanding for example of social consequences caused from opening the market for competition. Expert interviews were conducted by using semi-structured theme interview. Based on the results of this study, deregulation has proceeded quite differently in the three countries researched. Sweden is the most advanced country, where the passenger railway market is open for new entrants. Denmark and Estonia are lagging behind. Opening the market is considered positive among passengers and most of the experts interviewed. Common for the interviews were the labour unions negative perspective concerning deregulation. Despite the fact deregulation is considered positive among the respondents of the customer satisfaction survey, they could not name railway undertakings operating in their country. Generally respondents were satisfied with the commuter trains. Ticket price, punctuality of trains and itinerary affect the most to customer satisfaction.

”They Call it Christmas”. An Ethnological Analysis of Alienation in Tove Jansson’s Short Story The Fir Tree

Artikel i tidskrift med referee-praxis