1,113 research outputs found
"Meidän oma Yrjö" : Eemil Nestor Setälä ja Yrjö Wichmann yhteistyökumppaneina
E. N.
Setälä ja Yrjö Wichmann työskentelivät kollegoina sekä Helsingin
Yliopistossa että useissa tieteellisissä seuroissa suomen ja sen
sukukielten tutkimuksen arvostettuina edustajina. Varsinkin uransa
alkutaipaleella he olivat perheystäviä ja yhteistyökumppaneita,
kuitenkin niin, että Setälällä oli aina selvä johtoasema. Sen suomin
valtuuksin hän ohjasi ja määräsi Wichmannia ja muitakin nuorempia
kollegoitaan omasta näkökulmastaan tarkoituksenmukaisiin työtehtäviin ja
luottamustoimiin, jotka saattoivat olla hyvinkin työläitä ja
pitkäkestoisia. Artikkelissa ei kuvata Setälän ja Wichmannin
tieteellisen tutkimustyön sisältöjä eikä sen tuloksia. Sen sijaan
käsitellään heidän tieteenalansa yleistä tilannetta ja kuvataan heidän
työskentelyään tieteellisinä kollegoina 1800-luvun lopun ja 1900-luvun
ensimmäisten vuosikymmenten aikana. Artikkeli perustuu esitelmään, joka
pidettiin Suomalais-Ugrilaisen Seuran järjestämässä Yrjö Wichmann
-seminaarissa Helsingissä 19.10.2018.</p
Matias Aleksanteri Castrén ja Kalevalan ruotsinnos
Kun Elias Lönnrotin kokoama runoeepos, ns. Vanha Kalevala, ilmestyi vuonna 1835, se käänsi suomen kielen ja suomalaisen kulttuurin arvostuksen huimaan nousuun. Kalevala innosti myös maisteriopintojaan viimeistelevää, alkuaan pappisuralle aikonutta Matias Aleksanteri Castrénia suuntaamaan huomionsa suomen ja sen sukukielten tutkimukseen. Koska alkuperäistä Kalevalaa pystyivät lukemaan vain muutamat harvat oppineiston edustajat, Suomalaisen Kirjallisuuden Seura julisti kilpailun runomuotoisen ruotsin- tai saksankielisen käännöksen aikaansaamiseksi. Tällaisia ei kuitenkaan ilmaantunut. Helsingin yliopiston suomen kielen lehtori Carl Niclas Keckman luennoi Kalevalasta ja laati siitä sanatarkan ruotsinnoksen, mutta ei runomittaista versiota. Muutaman vuoden odotuksen jälkeen Kalevalasta jo aiemmin kiinnostunut Castrén ryhtyi kääntämään eeposta. Suomalaisen Kirjallisuuden Seuran stipendiaattina hän keräsi kesällä 1839 taustatietoa ja uutta kansanperinneaineistoa Vienan Karjalassa. Aktiivinen kääntäminen kesti noin kaksi vuotta. Käännöstyön ohella Castrén julkaisi dosentinväitöskirjan ja joitakin pienempiä tieteellisiä tutkimuksia. Kevätlukukaudella 1841 Castrén luennoi Helsingin yliopistossa Kalevalasta ja viimeisteli käännöstään. Se ilmestyi kesäkuussa 1841 ja sai hyvän vastaanoton. Esimerkiksi historiallis-vertailevan kielentutkimuksen kärkiedustajiin kuulunut Jacob Grimm perehtyi Kalevalaan ja luennoi siitä Berliinin tiedeakatemiassa Castrénin ruotsinnoksen perusteella. Castrénin ruotsinnos avasi uusia mahdollisuuksia Kalevalaa koskevalle tieteelliselle keskustelulle, koska eepos oli nyt aiempaa merkittävästi laajempien piirien luettavissa. Tärkeä rooli tässä keskustelussa oli itse Castrénilla ja hänen Kalevala-tulkinnoillaan. Kalevalan käännöksen myötä Castrén sai pysyvän kansainvälisen maineen arvostettuna kansanperinteen ja mytologian asiantuntijana. Kirjoitus perustuu Suomalais-Ugrilaisessa Seurassa 15.2.2019 pidettyyn esitelmään.] </li
Electronic-structure-induced deformations of liquid metal clusters
Ab initio molecular dynamics is used to study deformations of sodium clusters
at temperatures K. Open-shell Na cluster has two shape
isomers, prolate and oblate, in the liquid state. The deformation is stabilized
by opening a gap at the Fermi level. The closed-shell Na remains magic also
at the liquid state.Comment: REVTex, 11 pages, no figures, figures (2) available upon request
(e-mail to hakkinen at jyfl.jyu.fi), submitted to Phys. Rev.
Energy relaxation in graphene and its measurement with supercurrent
We study inelastic energy relaxation in graphene for low energies to find out
how electrons scatter with acoustic phonons and other electrons. By coupling
the graphene to superconductors, we create a strong dependence of the measured
signal, i.e.,\ critical Josephson current, on the electron population on
different energy states. Since the relative population of high- and low-energy
states is determined by the inelastic scattering processes, the critical
current becomes an effective probe for their strength. We argue that the
electron-electron interaction is the dominant relaxation method and, in our
model of two-dimensional electron-electron scattering, we find a scattering
time ps at T=500 mK, 1-2 orders of magnitude smaller than
predicted by theory.Comment: 10 pages, 13 figures submitted to Physical Review
Stability of conductance oscillations in monatomic sodium wires
We study the stability of conductance oscillations in monatomic sodium wires
with respect to structural variations. The geometry, the electronic structure
and the electronic potential of sodium wires suspended between two sodium
electrodes are obtained from self-consistent density functional theory
calculations. The conductance is calculated within the framework of the
Landauer-B\"utttiker formalism, using the mode-matching technique as formulated
recently in a real-space finite-difference scheme [Phys. Rev. B \textbf{70},
195402 (2004)]. We find a regular even-odd conductance oscillation as a
function of the wire length, where wires comprising an odd number of atoms have
a conductance close to the quantum unit , and even-numbered
wires have a lower conductance. The conductance of odd-numbered wires is stable
with respect to geometry changes in the wire or in the contacts between the
wire and the electrodes; the conductance of even-numbered wires is more
sensitive. Geometry changes affect the spacing and widths of the wire
resonances. In the case of odd-numbered wires the transmission is on-resonance,
and hardly affected by the resonance shapes, whereas for even-numbered wires
the transmission is off-resonance and sensitive to the resonance shapes.
Predicting the amplitude of the conductance oscillation requires a
first-principles calculation based upon a realistic structure of the wire and
the leads. A simple tight-binding model is introduced to clarify these results.Comment: 16 pages, 20 figure
Effect of neck strength training on health-related quality of life in females with chronic neck pain: a randomized controlled 1-year follow-up study
Abstract
Background
Chronic neck pain is a common condition associated not only with a decrease in neck muscle strength, but also with decrease in health-related quality of life (HRQoL). While neck strength training has been shown to be effective in improving neck muscle strength and reducing neck pain, HRQoL among patients with neck pain has been reported as an outcome in only two short-term exercise intervention studies. Thus, reports on the influence of a long-term neck strength training intervention on HRQoL among patients with chronic neck pain have been lacking. This study reports the effect of one-year neck strength training on HRQoL in females with chronic neck pain.
Methods
One hundred eighty female office workers, 25 to 53 years of age, with chronic neck pain were randomized to a strength training group (STG, n = 60), endurance training group (ETG, n = 60) or control group (CG, n = 60). The STG performed high-intensity isometric neck strengthening exercises with an elastic band while the ETG performed lighter dynamic neck muscle training. The CG received a single session of guidance on stretching exercises. HRQoL was assessed using the generic 15D questionnaire at baseline and after 12 months. Statistical comparisons among the groups were performed using bootstrap-type analysis of covariance (ANCOVA) with baseline values as covariates. Effect sizes were calculated using the Cohen method for paired samples.
Results
Training led to statistically significant improvement in the 15D total scores for both training groups, whereas no changes occurred for the control group (P = 0.012, between groups). The STG improved significantly in five of 15 dimensions, while the ETG improved significantly in two dimensions. Effect size (and 95% confidence intervals) for the 15D total score was 0.39 (0.13 to 0.72) for the STG, 0.37 (0.08 to 0.67) for the ETG, and -0.06 (-0.25 to 0.15) for the CG.
Conclusions
One year of either strength or endurance training seemed to moderately enhance the HRQoL. Neck and upper body training can be recommended to improve HRQoL of females with neck pain if they are motivated for long-term regular exercise.
Trial Registration
ClinicalTrials.gov NCT01057836peerReviewe
Broken Symmetry in Density-Functional Theory: Analysis and Cure
We present a detailed analysis of the broken-symmetry mean-field solutions
using a four-electron rectangular quantum dot as a model system. Comparisons of
the density-functional theory predictions with the exact ones show that the
symmetry breaking results from the single-configuration wave function used in
the mean-field approach. As a general cure we present a scheme that
systematically incorporates several configurations into the density-functional
theory and restores the symmetry. This cure is easily applicable to any
density-functional approach.Comment: 4 pages, 4 figures, submitted to PR
Structure and Magnetism of Neutral and Anionic Palladium Clusters
The properties of neutral and anionic Pd_N clusters were investigated with
spin-density-functional calculations. The ground state structures are
three-dimensional for N>3 and they are magnetic with a spin-triplet for 2<=N<=7
and a spin nonet for N=13 neutral clusters. Structural- and spin-isomers were
determined and an anomalous increase of the magnetic moment with temperature is
predicted for a Pd_7 ensemble. Vertical electron detachment and ionization
energies were calculated and the former agree well with measured values for
anionic Pd_N clusters.Comment: 5 pages, 3 figures, fig. 2 in color, accepted to Phys. Rev. Lett.
(2001
Close-Packing of Clusters: Application to Al_100
The lowest energy configurations of close-packed clusters up to N=110 atoms
with stacking faults are studied using the Monte Carlo method with Metropolis
algorithm. Two types of contact interactions, a pair-potential and a many-atom
interaction, are used. Enhanced stability is shown for N=12, 26, 38, 50, 59,
61, 68, 75, 79, 86, 100 and 102, of which only the sizes 38, 75, 79, 86, and
102 are pure FCC clusters, the others having stacking faults. A connection
between the model potential and density functional calculations is studied in
the case of Al_100. The density functional calculations are consistent with the
experimental fact that there exist epitaxially grown FCC clusters starting from
relatively small cluster sizes. Calculations also show that several other
close-packed motifs existwith comparable total energies.Comment: 9 pages, 7 figure
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