Local Interactions and Protein Folding: A Model Study on the Square and Triangular Lattices

We study a simple heteropolymer model containing sequence-independent local interactions on both square and triangular lattices. Sticking to a two-letter code, we investigate the model for varying strength $\kappa$ of the local interactions; $\kappa=0$ corresponds to the well-known HP model [K.F. Lau and K.A. Dill, Macromolecules 22, 3986 (1989)]. By exhaustive enumerations for short chains, we obtain all structures which act as a unique and pronounced energy minimum for at least one sequence. We find that the number of such designable structures depends strongly on $\kappa$. Also, we find that the number of designable structures can differ widely for the two lattices at a given $\kappa$. This is the case, for example, at $\kappa=0$, which implies that the HP model exhibits different behavior on the two lattices. Our findings clearly show that sequence-independent local properties of the chains can play an important role in the formation of unique minimum energy structures.Comment: 10 pages LaTeX, 3 Postscript figures. Figure and references adde

Monte Carlo Study of the Phase Structure of Compact Polymer Chains

We study the phase behavior of single homopolymers in a simple hydrophobic/hydrophilic off-lattice model with sequence independent local interactions. The specific heat is, not unexpectedly, found to exhibit a pronounced peak well below the collapse temperature, signalling a possible low-temperature phase transition. The system size dependence at this maximum is investigated both with and without the local interactions, using chains with up to 50 monomers. The size dependence is found to be weak. The specific heat itself seems not to diverge. The homopolymer results are compared with those for two non-uniform sequences. Our calculations are performed using the methods of simulated and parallel tempering. The performances of these algorithms are discussed, based on careful tests for a small system.Comment: 13 pages LaTeX, 6 Postscript figures, References adde

Identification of myocardial infarction by high-frequency serial ECG measurement

The purpose of this study is to attempt to identify acute myocardial infarction with high frequency serial electrocardiogram. High-frequency ECG and serial ECG are both unique ECG analysing techniques. The idea in this study is to combine these two and see if changes between different ECGs from the same person can provide us some information, whether it being in the high-frequency or normal frequency range of the ECG. To answer the questions, an existing database which contained multiple ECGs for each person with high sampling frequency was used. 5 different machine learning models were trained and tested with this database. The results of the machine learning methods were good, producing the mean accuracy of 91.9%, while the best model was the Extra Trees machine learning model. It produced the accuracy of 97.9% when applying cross-validation to the database. After these results, high-frequency serial ECG could be stated to be relevant. However, having ECG measured regularly can be expensive and time consuming. Therefore, the possibility of using a wearable ECG device was also studied. With a device called SAFE, developed by the University of Turku, a new high-frequency serial ECG database was gathered. The already existing machine learning model trained with the previous data was applied to this database and produced a mean accuracy of 90%. The quality of the ECGs gathered with the device were also deemed to be viable. Both high-frequency ECG and serial ECG were found to be relevant methods. A wearable device could be used for AMI detection if the ECG is sufficient enough. Future studies could include increasing the dataset size of the wearable device, investigate other myocardial diseases and exploring the possibilities of high-frequency ECG further

De l’alemany a l’anglès en les ciències econòmiques a Suècia

Els pioners de les ciències econòmiques a Suècia de fa cent anys estaven molt influenciats per idees provinents d’Alemanya. En els seus viatges d’estudis habitualment visitaven universitats alemanyes i escrivien els seus treballs d’investigació en alemany o suec. Aquesta situació va canviar posteriorment en favor de l’anglès.Un nivell semblant de transició de l’alemany a l’anglès durant el segle xx es pot trobar en la llengua dels llibres d’economia adquirits per les biblioteques, la llengua de les tesis doctorals d’economia i la llengua de les obres citades en aquestes tesis. Al mateix temps, l’ús del suec s’ha encongit. Com a possibles causes de l’abandó de l’alemany es discuteix la I Guerra Mundial, l’escola històrica, el període nazi i la II Guerra Mundial, la reducció de la importància de les distànciesgeogràfiques i la influència creixent en àmbits diferentsdels Estats Units.La pioniroj de la sveda ekonomiko antaŭ cento da jaroj estis multe influitaj de germanaj ideoj. Iliaj studvojaĝoj iris plejofte al germanaj universitatoj, kaj iliaj sciencaj verkoj estis kutime en la lingvoj germana aŭ sveda. Tio poste ŝanĝiĝis favore al la angla. Similan transiron de la germana al la angla dum la 20-a jarcento oni trovaskoncerne la lingvon de ekonomikaj libroj, akiritaj de bibliotekoj, la lingvon de doktoraj ekonomikaj disertacioj kaj la lingvon de cititaj verkoj en tiuj disertacioj. Samtempe la uzado de la sveda ŝrumpis. Kiel eblajn kaŭzojn de la forlaso de la germana ni pridiskutas la Unuan Mondmiliton, la historian skolon, la naziepokon kaj la Duan Mondmiliton, la malgrandigitan signifon de geografia distanco kaj la kreskantan plurflankan usonan influon

Utvärdering av fallviktskomprimeringsmetoden och snabbslagskomprimeringsmetoden för markförbättring

A soil improvement method with capacity to densify a larger amount of mass within a shorter period of time is highly appreciated as it could help to reduce the working time. Deposits of up to several meters thick soil can be complicated to compact homogeneously and accurately. For a vibratory roller or similar, it would be required that deposits are compacted in several phases by filling and compacting alternately. This may, on the other hand, be very time consuming. Therefore, compaction methods that can offer a performance ability to the desired level within only one phase are highly coveted. Among such methods are, for instance, the conventional falling weight compaction method, also known as dynamic compaction (DC), and the relatively recently developed rapid impact compaction (RIC) method. The thesis subject is a result of industrial interest in rapid impact compaction method. Industry is keen to try this innovative method, yet there is uncertainty whether the significant cost of the machines would lead to improvements in the work routines and efficiency justifying the cost. Hence, the thesis investigates how the dynamic compaction and rapid impact compaction compares, how the compaction energy in both methods affects the soil improvement results and, finally, how economical the rapid compaction is, when compared to the dynamic compaction. Prescribed guidelines along with previous performed compaction projects around the world connect the thesis to a complete analysis of the methods. Parallels have been drawn between the proposed directives and case studies, as well as the projects have been interpreted between each other. This has made it possible to demonstrate when the present methods are favourable to apply and, on the other hand, more unfavourable. The reader can also receive a basic knowledge of the associated soil mechanics as well as common geotechnical insights in the behaviour of soil at exposed state. This will give the reader a considerably better perception in the description of the methods.En markförbättringsmetod med kapacitet att packa en större mängd massa inom en kortare tidsperiod är högt värderat, eftersom det kan hjälpa att reducera arbetstiden. Markskikt med upp till flera meter tjocka jordmassor kan vara komplicerade att få enhetligt och noggrant packade. För en vibrationsvält eller dylikt skulle det krävas att markskikten packas i flertalet omgångar genom att fylla och packa om vartannat. Detta kan å andra sidan vara väldigt tidskrävande. Därför är komprimeringsmetoder, som kan erbjuda en prestationsförmåga till den begärda nivån inom endast en omgång, mycket eftertraktade. Till sådana metoder hör bland annat den traditionella fallviktskomprimeringsmetoden, även kallad dynamisk komprimering, samt den relativt nyligen utvecklade snabbslagskomprimeringsmetoden. Avhandlingsämnet är ett resultat av ett arbetsmarknadsintresse i snabbslagskomprimeringsmetoden. Branschen är angelägen om att prova denna innovativa metod. I nuläget finns en ovisshet kring huruvida den betydelsefulla kostnaden av maskinerna skulle leda till förbättringar i arbetsrutinerna och effektiviteten, som rättfärdigar kostnaden. Därmed undersöker examensarbetet hur fallviktskomprimeringen och snabbslagskomprimeringen jämförs, hur komprimeringsenergin i båda metoderna påverkar markförbättringsresultatet och, slutligen, hur ekonomisk snabbslagskomprimeringen är, när den jämförs med fallviktskomprimeringen. Föreskrivna riktlinjer tillsammans med tidigare utförda komprimeringsprojekt världen över knyter samman examensarbetet till en komplett analysering av metoderna. Paralleller har dragits mellan de anförda direktiven och fallstudierna, tillika som projekten sinsemellan har tolkats. Detta har gjort det möjligt att kunna påvisa när de föreliggande metoderna är gynnsamma att tillämpa och, å andra sidan, mindre ändamålsenliga. Läsaren tillhandahålles även en grundläggande vetskap kring den tillhörande jordmekaniken samt gängse förekommande geotekniska insikter i markens beteende vid utsatt tillstånd. Detta skall ge läsaren en avsevärt bättre uppfattning i samband med beskrivningen av metoderna

Analysis of chromosomal involvement in Yersinia pestis virulence plasmid expression

Virulence plasmid expression in the Yersinia has been shown to vary depending upon which species harbors the virulence plasmid suggesting that chromosomal regulation may in some way be involved. In this study, fertility plasmid expression in Y. pestis was investigated as a means of evaluating mechanisms of virulence plasmid regulation in this bacterium. The F plasmid was found to be minimally expressed in Y. pestis transferring at a rate of 8.8 $\times$ 10\sp{-5\%}. In addition, Y. pestis failed to express F pili as determined by infection with the male specific phage MS2. When F plasmids containing at least 2 E. coli F regulatory genes were transferred to Y. pestis and monitored for MS2 sensitivity, they were found to confer MS2 sensitivity to Y. pestis. In an attempt to determine if these known plasmid regulatory genes could influence virulence plasmid expression, three clones arcA, rfaH, and cpxA were observed in Y. pestis. All of these genes were found to increase the frequency of F transfer from Y. pestis, but none were able to alter virulence plasmid expression. The effects of anaerobic growth on plasmid expression were investigated. While anaerobicity was observed to have no effect on F plasmid expression, surprisingly virulence plasmid expression was found to be repressed in strains with and without the arcA gene. Further analysis of two $\beta$-galactosidase insertion mutants of Y. pestis revealed that both yopJ and yopE genes failed to be induced by the normal stimuli when the mutants were grown anaerobically. However, it was noted that when these strains were returned to an aerobic environment plasmid expression returned to normal. Varying gas mixtures were studied for their ability to repress plasmid expression, but only the original mix of 85%N\sb2, 5%CO\sb2, and 10%H\sb2 was able to repress plasmid expression. NaHCO\sb3 at a final concentration of 10mM was found to relieve growth restriction aerobically suggesting that the anaerobic repression was due to the formation of HCO\sb{3\sp-} in the presence of CO\sb2 and H\sb2.. These results represent a new means of relieving Yersinia plasmid-mediated growth restriction in vitro which may be related to the physiological environment encountered in vivo by this bacterium

Alien Registration- Sandelin, Hugo F. (Brunswick, Cumberland County)

https://digitalmaine.com/alien_docs/31717/thumbnail.jp

Alien Registration- Sandelin, Ida F. (Brunswick, Cumberland County)

https://digitalmaine.com/alien_docs/31718/thumbnail.jp