Spectral analysis of the Forbush decrease of 13 July 1982

The maximum entropy method has been applied in the spectral analysis of high-energy cosmic-ray intensity during the large Forbush event of July 13, 1982. An oscillation with period of about 2 hours and amplitude of 1 to 3% was found to be present during the decrease phase. This oscillation can be related to a similar periodicity in the magnetospheric field. However, the variation was not observed at all neutron monitor stations. In the beginning of the recovery phase, the intensity oscillated with a period of about 10 hours and amplitude of 3%

A facility for investigation of multiple hadrons at cosmic-ray energies

An experimental arrangement for studying multiple hadrons produced in high-energy hadron-nucleus interactions is under construction at the university of Turku. The method of investigation is based on the detection of hadrons arriving simultaneously at sea level over an area of a few square meters. The apparatus consists of a hadron spectrometer with position-sensitive detectors in connection with a small air shower array. The position resolution using streamer tube detectors will be about 10 mm. Energy spectra of hadrons or groups of simultaneous hadrons produced at primary energies below 10 to the 16th power eV can be measured in the energy range 1 to 2000 GeV

Observations of cosmic-ray modulations in the fall, 1984

Modulation of cosmic-ray energy spectrum was studied by using the Turku double neutron monitor. The multiplicity region of detected neutrons produced by cosmic ray hadrons in the monitor was divided into seven categories corresponding to mean energies 0.1, 0.3, 1.0, 3.2, 8.6, 21, and 94 GeV of hadrons at sea level. Based on 24-hour frequencies, a statistical analysis showed that modulation of the intensity in all categories occurred during several periods in the fall 1984. The magnitude of the variation was a few per cent

Investigation of cosmic rays in very short time scales

A fast databuffer system, where cosmic ray events in the Turku hadron spectrometer, including particle arrival times are recorded with time resolution of 100 ns was constructed. The databuffer can be read continuously by a microprocessor, which preanalyzes the data and transfers it to the main computer. The time span, that can be analyzed in every detail, is a few seconds. The high time resolution enables a study of time correlated groups of high energy particles. In addition the operational characteristics of the spectrometer can be monitored in detail

Tunnel Spectroscopy of a Proximity Josephson Junction

We present tunnel spectroscopy experiments on the proximity effect in lateral superconductor-normal metal-superconductor (SNS) Josephson junctions. Our weak link is embedded into a superconducting (S) ring allowing phase biasing of the Josephson junction by an external magnetic field. We explore the temperature and phase dependence of both the induced mini-gap and the modification of the density of states in the normal (N) metal. Our results agree with a model based on the quasiclassical theory in the diffusive limit. The device presents an advanced version of the superconducting quantum interference proximity transistor (SQUIPT), now reaching flux sensitivities of 3 nA$/\Phi_0$ where $\Phi_0$ is the flux quantum.Comment: 5 pages, 4 figure

The 1.88 Ga Kotalahti and Vammala nickel belts, Finland: geochemistry of the mafic and ultramafic metavolcanic rocks

The mafic and ultramafic volcanic rocks within the Svecofennian (1.88 Ga) Kotalahti and Vammala Nickel Belts, Finland, are spatially associated and coeval with a suite of mineralized mafic–ultramafic intrusions. They have been divided into five suites based on major element geochemistry and spatial distribution: the Rantasalmi high- and low-Mg suites, the Vammala high-Mg suite, and the Rantasalmi, Kestilä and Pielavesi low-Mg suites. The Rantasalmi and Vammala high-Mg suites are very similar and probably comagmatic, and the Kestilä and Rantasalmi low-Mg suites are derived from them by a combination of fractionation and crustal assimilation. The Pielavesi suite is interpreted as an unrelated suite of island-arc affinity.On the basis of their trace element contents, the Kotalahti Belt intrusions are comagmatic with part of the analyzed volcanic rocks. In the Vammala Belt it is likely that the parent magmas to the intrusions and picrite magmas have a common mantle source but have evolved along distinct paths, and the picrites probably do not represent parent magmas tapped directly from the intrusions. Platinum-group element data show localised evidence for depletionby sulfide extraction. Vammala picrites are predominantly S-undersaturated, with the exception of lavas in the Stormi area. In the Kotalahti Belt the volcanic rocks are predominantlyS-undersaturated, while the volcanic rocks in the more northern part of the Belt are predominantly S-saturated. These spatial differences imply that the PGE contents of the metavolcanic rocks can be used as regional area selection criteria for intrusive nickel-copper-(PGE) deposits within the Finnish Svecofennian

Diversity of actin architecture in human osteoclasts: Network of curved and branched actin supporting cell shape and intercellular micrometer level tubes

Osteoclasts are multinucleated bone-resorbing cells with a dynamic actin cytoskeleton. Osteoclasts are derived from circulating mononuclear precursors. Confocal and stimulated emission depletion (STED) super-resolution microscopy was used to investigate peripheral blood-derived human osteoclasts cultured on glass surfaces. STED and confocal microscopy demonstrated that the actin was curved and branched, for instance, in the vicinity of membrane ruffles. The overall architecture of the curved actin network extended from the podosomes to the top of the cell. The other novel finding was that a micrometer-level tube containing actin bridged the osteoclasts well above the level of the culture glass. The actin filaments of the tubes originated from the network of curved actin often surrounding a group of nuclei. Furthermore, nuclei were occasionally located inside the tubes. Our findings demonstrated the accumulation of c-Src, cortactin, cofilin, and actin around nuclei suggesting their role in nuclear processes such as the locomotion of nuclei. ARP2/3 labeling was abundant at the substratum level of osteoclasts and in the branched actin network, where it localized to the branching points. We speculate that the actin-containing tubes of osteoclasts may provide a means of transportation of nuclei, e.g., during the fusion of osteoclasts. These novel findings can pave the way for future studies aiming at the elucidation of the differentiation of multinucleated osteoclasts.</p

Pediatric malignancies in neurofibromatosis type 1: A population‐based cohort study

Neurofibromatosis type 1 (NF1) is a cancer predisposition syndrome with an incidence of 1:2,000. Patients with NF1 have an increased cancer risk and mortality, but there are no population‐based cohort studies specifically investigating the risk of childhood malignancies. We used the Finnish NF1 cohort to analyze the incidence, risk and prognosis of malignancies in NF1 patients </p