Mass distribution of neutron stars and black holes in X-ray binaries

Abstract. The aim of this thesis is to make a literature review of the mass distribution of neutron stars and black holes in X-ray binaries. X-ray binaries are binary systems which contain a stellar remnant and a main sequence star. The stellar remnant accretes matter from the donor, a main sequence star. This matter forms an accretion disk around the remnant and as the matter spirals in toward the surface of the remnant it becomes so energetic that it radiates its gravitational potential energy away as X-rays. There are next to no objects between the lightest known black holes and heaviest neutron stars making their distribution uneven. The so-called lower mass gap is between 2.5 M⊙ and 5.0 M⊙. This was not expected since the stellar masses have a smooth distribution, thus there must be something afecting the formation of neutron stars and black holes. The causes for this mass gap are not yet well known but as more data is gathered from X-ray binary systems we have come up with few explanations for this gap. In general, we either do not understand the situation completely or then there is some bias introduced from the observations as stellar remnants are hard to detect if they are not located inside a binary system. Recent data about the masses of neutron stars and black holes are explored and one can clearly see the mass gap

PEAK VELOCITY OF NORDIC SKI DOUBLE POLE TECHNIQUE

One of the event styles in cross-country skiing is the classic technique in which the skis move in groomed tracks. Double poling is a technique used under the classic skiing style, and is defined as when the upper body provides most of the propulsion via bilateral pole pushes. Double poling during classic cross-country skiing has become more popular in the past twenty years. It has also been shown to have strong correlations with increased race speed (Smith, Fewster, & Braudt, 1996). Maximal velocity considers an overall velocity of the movements, but does not specify at which point during the poling phase that peak velocity occurs. By breaking a movement down into its components one may be able to critique technique more specifically. This study examined the point at which peak linear velocity occurred during the double poling cycle time in Nordic stand-up and sit-down skiing

Virtual teamwork:features of effective teamwork

Abstract. Nowadays organizations rely more and more on distance working and virtual teams. The aim of this study is to identify the characteristics of effective virtual teamwork and to provide a wide view on what a team is, how it is defined, which are the enabling factors for successful distance teamwork and what are the benefits of virtual distance teamwork. This thesis is a qualitative study and was conducted as a systematic literature review. Data is collected both from University of Oulu Nelli portal and The University of Melbourne Discovery Database and studies up to 15 years old are approved. Based on the results, teams are open and complex systems where the personalities, level of expertise and current cognition of the team members modify the team building, learning and working. High team resilience in virtual teams allows teams to cope through multiple tasks and is also directly connected to the outcome and effectiveness of team working. Literature describes team learning as essential for team working, and it can be enhanced via shared understanding and communication. A good team consists of members who are willing to cope with others: all other team building blocks are unnecessary if members are not able to collaborate. The most important role of the leader is to motivate and divide clear tasks and roles to virtual team members. There are multiple benefits in virtual distance teamworking, e.g. we will show that job satisfaction and productivity may increase when work can be done regardless of time and space. These results suggest that among other things, basic team learning, resilience and effective communication help to build trusting and effective virtual working teams. This data supports the view that it is possible for teams to work even cross-culturally without seeing each other by using only electric technology. Digitalisation enables effective communication and sharing, which in turn helps to build trust among members — even if they will never see each other face-to-face

ELECTROMYOGRAPHICAL ANALYSIS OF DOUBLE POLE ERGOMETRY: STANDING VS. SITTING

This study assessed the difference in stand-up athlete’s muscle activity of the rectus femoris in standing and sitting using a double pole ergometer. Five subjects participated in two technique specific peak VO2 tests, and a percentage of the maximum scores were used to determine stages for analysis of the electromyography data that was collected. An ANOVA revealed a significant difference in electromyographical activity between ski position and stage using a pre-determined alpha level of

ELECTROMYOGRAPHICAL ANALYSIS OF DOUBLE POLE ERGOMETRY: STANDING VS. SITTING.

This study assessed the difference in stand-up athlete’s muscle activity of the rectus femoris in standing and sitting using a double pole ergometer. Five subjects participated in two technique specific peak VO2 tests, and a percentage of the maximum scores were used to determine stages for analysis of the electromyography data that was collected. An ANOVA revealed a significant difference in electromyographical activity between ski position and stage using a pre-determined alpha level of

An analysis of the acoustic cavitation noise spectrum: The role of periodic shock waves

Research on applications of acoustic cavitation is often reported in terms of the features within the spectrum of the emissions gathered during cavitation occurrence. There is, however, limited understanding as to the contribution of specific bubble activity to spectral features, beyond a binary interpretation of stable versus inertial cavitation. In this work, laser-nucleation is used to initiate cavitation within a few millimeters of the tip of a needle hydrophone, calibrated for magnitude and phase from 125 kHz to 20 MHz. The bubble activity, acoustically driven at f0 = 692 kHz, is resolved with high-speed shadowgraphic imaging at 5 × 106 frames per second. A synthetic spectrum is constructed from component signals based on the hydrophone data, deconvolved within the calibration bandwidth, in the time domain. Cross correlation coefficients between the experimental and synthetic spectra of 0.97 for the f 0/2 and f 0/3 regimes indicate that periodic shock waves and scattered driving field predominantly account for all spectral features, including the sub-harmonics and their over-harmonics, and harmonics of f 0

”Oletko sä viikinki vai oletko sä ämmä!”:sankarimyytin ja maskuliinisuuden ongelmallisuus suomalaisten kamppailu-urheilijoiden omaelämäkerroissa

Tiivistelmä. Tässä pro gradu -tutkielmassa tarkastelen suomalaisten kamppailu-urheilijoiden omaelämäkertoja narratiivisen eli kerronnallisen tutkimuksen ja kriittisen maskuliinisuuden tutkimuksen näkökulmasta. Kohdeteokseni ovat Tony Halmeen Jumala armahtaa, minä en (1998) ja Jarkko Steniuksen Nyrkkisankari (2015). Tutkielman tarkoituksena on näyttää, millaisia kertomuksia teokset tuottavat sankaruudesta ja maskuliinisuudesta. Lähtökohtanani omaelämäkerrallisuutta tarkastellessa on oletus, että elämästä kertominen ja identiteetin rakentuminen noudattavat ympäröivästä kulttuurista nousevia kertomuksen malleja, erityisesti sankaritarinaa. Teosten sankarinarratiiveja tarkastellessani nojaan Joseph Campbellin käsitykseen sankarin matkasta monomyyttinä sekä Vladimir Proppin teorioihin ihmesatujen funktioista ja aktanttirooleista. Kertomuksia maskuliinisuudesta tutkin Judith Butlerin sukupuoliteorian mukaisina performatiiveina ja performansseina. Maskuliinisuuden muodoista nostan esiin marginaalisen, hegemonisen ja hypermaskuliinisuuden käsitteet. Analyysini osoittaa, että kohdeteokseni ovat sankarihahmon seikkailuita kuvaavaa viihdekirjallisuutta, jossa on nähtävissä myös terapeuttista tunnustuksellisuutta ja elämäntaito-oppaiden piirteitä. Intersektionaalisesti tarkasteltuna kertojat ovat altavastaaja-asemassa lähtökohtiensa osalta. Huono-osaisuus ja etenkin isättömyys ajaa heidät etsimään identiteettinsä rakennuspalasia hypermaskuliinisista konteksteista: militarismista, kamppailu-urheilusta ja toimintaelokuvien narratiiveista. Sankarin matkaan liittyvät initiaatiot ovat keskeinen osa teosten narratiiveja. Sekä maskuliinisuutta että sankaruutta toteutetaan selviytymällä erilaisista haasteista ja ponnisteluista. Narratiiveissa kertojahahmot toteuttavat hegemonisen maskuliinisuuden vaatimuksia: heteronormatiivisuutta, homofobiaa, seksismiä, tunnekylmyyttä, fyysistä voimaa ja väkivaltaa korostavaa mieheyttä. Keskeinen löydökseni on, että teosten kertojahahmot performoivat valikoidusti hegemonisen maskuliinisuuden ylivietyjä, hypermaskuliinisia piirteitä populaarikulttuurin sankareita idolisoiden. Näin tehdessään he kuitenkin marginalisoivat itsensä edustamaan väkivaltaista ja itsetuhoista toksista maskuliinisuutta. Kohdeteosten kertomukset myös eroavat toisistaan. Steniuksella sankarin matka on symbolinen matka kertojan psyykeen konflikteihin ja narratiivi muistuttaa kääntymyskertomusta. Keskeinen ero teosten narratiivien välillä on niiden suhde hypermaskuliiniseen sankaruuteen, jonka Halme näkee performatiivin kautta tavoiteltavana ideaalina ja Stenius taas lopulta haitallisena miehuuden mallina. Sankarinarratiivien alaluokkina teoksissa esiintyy kertomustyypit ryysyistä rikkauksiin, oman onnensa seppä, työläissankari, kehityskertomus ja sankari altavastaajana. Tutkimukseni avaa yhteiskunnassa ja urheilussa vallitsevia maskuliinisuuden ja sankaruuden performatiiveja sekä esittää sankarin myyttisen matkan olevan keskeinen narratiivi kulttuurissamme