Low Scale Non-universal, Non-anomalous U(1)'_F in a Minimal Supersymmetric Standard Model

We propose a non-universal U(1)'_F symmetry combined with the Minimal Supersymmetric Standard Model. All anomaly cancellation conditions are satisfied without exotic fields other than three right-handed neutrinos. Because our model allows all three generations of chiral superfields to have different U(1)'_F charges, upon the breaking of the U(1)'_F symmetry at a low scale, realistic masses and mixing angles in both the quark and lepton sectors are obtained. In our model, neutrinos are predicted to be Dirac fermions and their mass ordering is of the inverted hierarchy type. The U(1)'_F charges of the chiral super-fields also naturally suppress the mu term and automatically forbid baryon number and lepton number violating operators. While all flavor-changing neutral current constraints in the down quark and charged lepton sectors can be satisfied, we find that constraint from D0-D0bar turns out to be much more stringent than the constraints from the precision electroweak data.Comment: 21 pages, 2 figures; v2: discussion on sparticle mass spectrum included, 27 pages, 2 figure

Quintessential Kination and Leptogenesis

Thermal leptogenesis induced by the CP-violating decay of a right-handed neutrino (RHN) is discussed in the background of quintessential kination, i.e., in a cosmological model where the energy density of the early Universe is assumed to be dominated by the kinetic term of a quintessence field during some epoch of its evolution. This assumption may lead to very different observational consequences compared to the case of a standard cosmology where the energy density of the Universe is dominated by radiation. We show that, depending on the choice of the temperature T_r above which kination dominates over radiation, any situation between the strong and the super--weak wash--out regime are equally viable for leptogenesis, even with the RHN Yukawa coupling fixed to provide the observed atmospheric neutrino mass scale ~ 0.05 eV. For M< T_r < M/100, i.e., when kination stops to dominate at a time which is not much later than when leptogenesis takes place, the efficiency of the process, defined as the ratio between the produced lepton asymmetry and the amount of CP violation in the RHN decay, can be larger than in the standard scenario of radiation domination. This possibility is limited to the case when the neutrino mass scale is larger than about 0.01 eV. The super--weak wash--out regime is obtained for T_r << M/100, and includes the case when T_r is close to the nucleosynthesis temperature ~ 1 MeV. Irrespective of T_r, we always find a sufficient window above the electroweak temperature T ~ 100 GeV for the sphaleron transition to thermalize, so that the lepton asymmetry can always be converted to the observed baryon asymmetry.Comment: 13 pages, 8 figure

Alaraajojen lihasten spastisuus ennen ja jälkeen avustetun polkuharjoittelun

Opinnäytetyön tavoitteena oli kerätä tietoa aivoverenkiertohäiriötä, selkäydinvauriota sekä CP-vammaa sairastavien neurologisten asiakkaiden spastisten alaraajojen lihasten spastisuuden aiheuttaman lihasaktivaation mahdollisesta muutoksesta ennen ja jälkeen avustetulla polkulaitteella suoritetun polkuharjoituksen. Tarkoituksena oli tuottaa tutkittua tietoa kyseisen terapiamuodon vaikutuksesta edellä mainittuja oireyhtymiä sairastavien kuntoutuksessa. Toimeksiantaja voi hyödyntää tuloksia suunnitellessaan ja arvioidessaan neurologisten asiakkaiden kuntoutuksessa käytettäviä terapiamuotoja. Lisäksi tarkoituksena oli tuottaa fysioterapia-alalle tietoa terapiamuodon vaikutuksesta alaraajojen spastisuuteen. Työn tekijät syvensivät työn kautta omaa ammattitaitoaan tulevaa ammattia varten. Opinnäytetyömme tutkimusongelmana oli miten polkulaitteella suoritettu 20 minuutin avustettu polkuliike vaikuttaa aivoverenkiertohäiriötä, selkäydinvauriota sekä CP-vammaa sairastavien neurologisten asiakkaiden spastisuuden aiheuttamaan alaraajojen lihasaktivaatioon. Opinnäytetyö toteutettiin tapaustutkimuksena, johon osallistui viisi tutkimushenkilöä. Tutkimuksen aineisto kerättiin määrällisin menetelmin, joita olivat elektromyografia (EMG), Modified Modified Ashworth Scale (MMAS) sekä kysymyslomake. EMG ja MMAS mittaukset suoritettiin yhtäaikaisesta ennen polkuharjoitusta ja sen jälkeen. Mittareilla saadut tulokset analysoitiin MegaWin-ohjelmalla ja Microsoft Excel-taulukkolaskentaohjelmalla. Tulokset on esitetty numeerisessa ja graafisessa muodossa. Tutkimuksesta saatujen tulosten mukaan spastisuuden aiheuttama lihasaktivaatio väheni polkuharjoittelun jälkeen jokaisessa mitatussa lihaksessa EMG- ja MMAS -mittareilla mitattuna. Myös kysymyslomakkeella saatujen tulosten mukaan polkuharjoittelun vaikutukset spastisuuteen ovat positiivisia. Näin ollen tutkimustulosten perusteella avustetulla polkuharjoittelulla oli lihasten spastisuutta alentava vaikutus. Pienen tutkimusjoukon johdosta tuloksia ei voi kuitenkaan yleistää, mutta ne ovat suuntaa-antavia.The aim of this thesis is to gather information on possible changes in the spasticity of the lower limb muscles before and after assisted cycling exercise in clients with stroke, spinal cord injury and cerebral palsy. The purpose of this thesis is to produce information about the effects of the assisted cycling exercise in rehabilitation with clients suffering from the above mentioned injuries. The commissioner, Kemijärven Fysikaalinen Hoitolaitos Ky, can benefit from the achieved results while planning the rehabilitation of neurological clients. The authors’ purpose is to generate knowledge on the effects of assisted cycling exercise in spasticity of the lower limb muscles for physiotherapy field to use. The authors benefit from the thesis by obtaining their own expertise for the upcoming profession. The research problem of this thesis was to discover how the 20-minute assisted cycling exercise affects the spasticity of the lower limbs muscles in clients with stroke, spinal cord injury and cerebral palsy. This thesis is a case study in which participated five study subjects. The research data was gathered with the following quantitative methods: Electromyography (EMG), Modified Modified Ashworth Scale (MMAS) and questionnaire. EMG and MMAS were administrated simultaneously before and after assisted cycling exercise. The results were analysed with MegaWin-program and Microsoft Excel Spreadsheet. The results are displayed in numerical and graphical form. The results of this thesis show that after the assisted cycling exercise the muscle activation caused by spasticity, previously measured by EMG and MMAS, was reduced in every tested muscle. According to results from the questionnaire the effects of assisted cycling exercise was also positive. Therefore, it could be said that assisted cycling exercise reduces the spasticity in lower limb muscles. Due to the limited amount of participant in the study group, the results cannot be generalised, nevertheless, they can be used as directional information

Gauge mediated supersymmetry breaking and the cosmology of Left-Right symmetric model

Left-Right symmetry including supersymmetry presents an important class of gauge models which may possess natural solutions to many issues of phenomenology. Cosmology of such models indicates a phase transition accompanied by domain walls. Such walls must be unstable in order to not conflict with standard cosmology, and can further be shown to assist with open issues of cosmology such as dilution of unwanted relic densities and leptogenesis. In this paper we construct a model of gauge mediated supersymmetry breaking in which parity breaking is also signalled along with supersymmetry breaking and so as to be consistent with cosmological requirements. It is shown that addressing all the stated cosmological issues requires an extent of fine tuning, while in the absence of fine tuning, leptogenesis accompanying successful completion of the phase transition is still viable

Electrical Transport in High Quality Graphene pnp Junctions

We fabricate and investigate high quality graphene devices with contactless, suspended top gates, and demonstrate formation of graphene pnp junctions with tunable polarity and doping levels. The device resistance displays distinct oscillations in the npn regime, arising from the Fabry-Perot interference of holes between the two pn interfaces. At high magnetic fields, we observe well-defined quantum Hall plateaus, which can be satisfactorily fit to theoretical calculations based on the aspect ratio of the device.Comment: to appear in a special focus issue in New Journal of Physic

Zone Diagrams in Euclidean Spaces and in Other Normed Spaces

Zone diagram is a variation on the classical concept of a Voronoi diagram. Given n sites in a metric space that compete for territory, the zone diagram is an equilibrium state in the competition. Formally it is defined as a fixed point of a certain "dominance" map. Asano, Matousek, and Tokuyama proved the existence and uniqueness of a zone diagram for point sites in Euclidean plane, and Reem and Reich showed existence for two arbitrary sites in an arbitrary metric space. We establish existence and uniqueness for n disjoint compact sites in a Euclidean space of arbitrary (finite) dimension, and more generally, in a finite-dimensional normed space with a smooth and rotund norm. The proof is considerably simpler than that of Asano et al. We also provide an example of non-uniqueness for a norm that is rotund but not smooth. Finally, we prove existence and uniqueness for two point sites in the plane with a smooth (but not necessarily rotund) norm.Comment: Title page + 16 pages, 20 figure

The μ\mu problem, and B and L Conservation with a Discrete Gauge R Symmetry

We examine in a generic context how the $\mu$ problem can be resolved by means of a spontaneously broken gauge symmetry. We then focus on the new scheme based on a discrete gauge R symmetry which is spontaneously broken by nonperturbative hidden sector dynamics triggering supersymmetry breaking also. The possibility to suppress the dangerous baryon and/or lepton number violating interactions by means of this discrete R symmetry is examined also together with some phenomenological consequences.Comment: 13 pages, RevTex, no figure

U(2) and Maximal Mixing of nu_{mu}

A U(2) flavor symmetry can successfully describe the charged fermion masses and mixings, and supress SUSY FCNC processes, making it a viable candidate for a theory of flavor. We show that a direct application of this U(2) flavor symmetry automatically predicts a mixing of 45 degrees for nu_mu to nu_s, where nu_s is a light, right-handed state. The introduction of an additional flavor symmetry acting on the right-handed neutrinos makes the model phenomenologically viable, explaining the solar neutrino deficit as well as the atmospheric neutrino anomaly, while giving a potential hot dark matter candidate and retaining the theory's predictivity in the quark sector.Comment: 20 pages, 1 figur

Systematics of parton-medium interaction from RHIC to LHC

Despite a wealth of experimental data for high-P_T processes in heavy-ion collisions, discriminating between different models of hard parton-medium interactions has been difficult. A key reason is that the pQCD parton spectrum at RHIC is falling so steeply that distinguishing even a moderate shift in parton energy from complete parton absorption is essentially impossible. In essence, energy loss models are effectively only probed in the vicinity of zero energy loss and, as a result, at RHIC energies only the pathlength dependence of energy loss offers some discriminating power. At LHC however, this is no longer the case: Due to the much flatter shape of the parton p_T spectra originating from 2.76 AGeV collisions, the available data probe much deeper into the model dynamics. A simultaneous fit of the nuclear suppression at both RHIC and LHC energies thus has great potential for discriminating between various models that yield equally good descriptions of RHIC data alone.Comment: Talk given at Quark Matter 2011, 22-28 May 2011, Annecy, Franc