Charge-noise tolerant exchange gates of singlet-triplet qubits in asymmetric double quantum dots

In the semi-conductor double quantum dot singlet-triplet qubit architecture, the decoherence caused by the qubit's charge environment poses a serious obstacle in the way towards large scale quantum computing. The effects of the charge decoherence can be mitigated by operating the qubit in the so called sweet spot regions where it is insensitive to electrical noise. In this paper, we propose singlet-triplet qubits based on two quantum dots of different sizes. Such asymmetric double dot systems allow the implementation of exchange gates with controllable exchange splitting $J$ operated in the doubly occupied charge region of the larger dot, where the qubit has high resilience to charge noise. In the larger dot, $J$ can be quenched to a value smaller than the intra-dot tunneling using magnetic fields, while the smaller dot and its larger splitting can be used in the projective readout of the qubit

ALASELKÄPOTILAIDEN FYSIOTERAPIA LAPIN SAIRAANHOITOPIIRIN TERVEYSKESKUKSISSA

Opinnäytetyön tarkoituksena oli selvittää alaselkäpotilaan fysioterapian toteutuminen Lapin sairaanhoitopiirin terveyskeskuksissa ennen ja jälkeen Lapin keskussairaalan fysiatrian poliklinikalla käynnin. Tarkoituksena oli myös selvittää, minkälaisia fysioterapiamenetelmiä terveyskeskuksissa käytetään. Työn tavoitteena oli tuottaa tietoa alaselkäpotilaiden fysioterapian toteutumisesta ennen ja jälkeen fysiatrian poliklinikalla käynnin. Lisäksi tavoitteena oli tehdä kehittämisehdotukset alaselkäpotilaan hoitoketjun toiminnan parantamiseksi. Tutkimus oli muodoltaan määrällinen tutkimus, jossa oli lisäksi tarkentavia avoimia kysymyksiä. Tutkimus toteutettiin kyselytutkimuksena ja se lähetettiin terveyskeskusten alaselkäpotilaita hoitaville fysioterapeuteille sähköpostitse huhtikuussa 2016. Kyselyyn saatiin 31 hyväksyttyä vastausta ja vastauspro-sentiksi muodostui 81,5. Tutkimuksen määrällisten vastausten analysointi toteutettiin Webropol-työkalun ja IBM SPSS Statistic -ohjelman avulla. Tutkimuksen avointen kysymyksien analysoinnissa käytettiin laadullista sisällönanalyysin menetelmää. Alaselkäpotilaiden fysioterapia terveyskeskuksissa toteutui fysiatrian poliklinikalla käynnin jälkeen pääosin hoitoketjun mukaisesti, ennen fysiatrian poliklinikalla käyntiä fysioterapia ei aina toteutunut hoitoketjun mukaisesti. Pääosa vastaajista koki alaselkäpotilaan hoitoketjun toimivaksi ja hoitopalautteiden olevan fysioterapeuttien käytettävissä. Hierontaa ja passiivisia liikehoitoja käytettiin pääasiallisina hoitomenetelminä alaselkäpotilaan hoitosuosituksista poiketen yllättävän usein, muilta osin fysioterapiassa käytettiin hoitosuositusten mukaisia menetelmiä. Tutkimuksen tuloksia voidaan hyödyntää hoitoketjun toiminnan kehittämiseen ja potilaiden parempaan hoitoon.The purpose of this thesis was to find out how the physiotherapy of lower back pain patients was executed in the healthcare centres of Lapland Hospital District before and after patient visits to the physiatric polyclinic of the Central Hospital of Lapland. Another purpose of the thesis was to map out what kind of physiotherapy methods are used in healthcare centres. Finally, this thesis aimed to produce development suggestions for the care chain of lower back pain patients. This thesis is an example of quantitative research, but openended questions were also used. Thus, survey research was chosen as the research strategy and a questionnaire as the research method. The questionnaire was sent by email to the physiotherapists of healthcare centres treating lower back pain patients in April 2016. It received 31 approved responses, making the response rate 81.5 percent. Next, the quantitative data was analysed with the help of Webropol survey tool and IBM SPSS Statistics programme. In contrast, the qualitative data was analysed with the help of content analysis. The data revealed that the physiotherapy of lower back pain patients in healthcare centres after a patient has visited the physiatric polyclinic was executed just as the care chain recommends. On the other hand, before a visit to the physiatry polyclinic, physiotherapy was not always executed as the care chain recommends. However, most of the physiotherapists felt that the care chain of low back pain patients is functional and that feedback from the physiatry polyclinic was readily available to the healthcare centres. The data also revealed that, contrary to recommendations, massage and passive movement are used quite often in the physiotherapy of lower back pain patients, while other recommendations are followed. Finally, the results of this thesis can be used to develop the care chain and to offer better treatment to the patients

Validity of the single-particle description and charge noise resilience for multielectron quantum dots

We construct an optimal set of single-particle states for few-electron quantum dots (QDs) using the method of natural orbitals (NOs). The NOs include also the effects of the Coulomb repulsion between electrons. We find that they agree well with the noniteracting orbitals for GaAs QDs of realistic parameters, while the Coulomb interactions only rescale the radius of the NOs compared to the noninteracting case. We use NOs to show that four-electron QDs are less susceptible to charge noise than their two-electron counterparts.Comment: 11+ pages, 5 figure

Non-adiabatic charge state transitions in singlet-triplet qubits

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Soluble activin type IIB receptor improves fracture healing in a closed tibial fracture mouse model

Fractures still present a significant burden to patients due to pain and periods of unproductivity. Numerous growth factors have been identified to regulate bone remodeling. However, to date, only the bone morphogenetic proteins (BMPs) are used to enhance fracture healing in clinical settings. Activins are pleiotropic growth factors belonging to the TGF-beta superfamily. We and others have recently shown that treatment with recombinant fusion proteins of activin receptors greatly increases bone mass in different animal models by trapping activins and other ligands thus inhibiting their signaling pathways. However, their effects on fracture healing are less known. Twelve-week old male C57Bl mice were subjected to a standardized, closed tibial fracture model. Animals were divided into control and treatment groups and were administered either PBS control or a soluble activin type IIB receptor (ActRIIB-Fc) intraperitoneally once a week for a duration of two or four weeks. There were no significant differences between the groups at two weeks but we observed a significant increase in callus mineralization in ActRIIB-Fc-treated animals by microcomputed tomography imaging at four weeks. Bone volume per tissue volume was 60%, trabecular number 55% and bone mineral density 60% higher in the 4-week calluses of the ActRIIB-Fc-treated mice (p<0.05 in all). Biomechanical strength of 4-week calluses was also significantly improved by ActRIIBFc treatment as stiffness increased by 64% and maximum force by 45% (p<0.05) compared to the PBS-injected controls. These results demonstrate that ActRIIB-Fc treatment significantly improves healing of closed long bone fractures. Our findings support the previous reports of activin receptors increasing bone mass but also demonstrate a novel approach for using ActRIIB-Fc to enhance fracture healing.Peer reviewe

Genetic risk factors in Finnish patients with Parkinson's disease

Introduction Variation contributing to the risk of Parkinson's disease (PD) has been identified in several genes and at several loci including GBA, SMPD1, LRRK2, POLG1, CHCHD10 and MAPT, but the frequencies of risk variants seem to vary according to ethnic background. Our aim was to analyze how variation in these genes contributes to PD in the Finnish population. Methods The subjects consisted of 527 Finnish patients with early-onset PD, 325 patients with late-onset PD and 403 population controls. We screened for known genetic risk variants in GBA, SMPD1, LRRK2, POLG1, CHCHD10 and MAPT. In addition, DNA from 225 patients with early-onset Parkinson's disease was subjected to whole exome sequencing (WES). Results We detected a significant difference in the length variation of the CAG repeat in POLG1 between patients with early-onset PD compared to controls. The p.N370S and p.L444P variants in GBA contributed to a relative risk of 3.8 in early-onset PD and 2.5 in late-onset PD. WES revealed five variants in LRRK2 and SMPD1 that were found in the patients but not in the Finnish ExAC sequences. These are possible risk variants that require further confirmation. The p.G2019S variant in LRRK2, common in North African Arabs and Ashkenazi Jews, was not detected in any of the 849 PD patients. Conclusions The POLG1 CAG repeat length variation and the GBA p.L444P variant are associated with PD in the Finnish population.Peer reviewe