182 research outputs found
Periodicity in some light curves of the solar analogue V352 Canis Majoris
Aims. We applied the Continuous Period Search (CPS) method to 14 yr of V-band photometry of the active G6.5 solar analog V352 CMa. Our aim was to show that CPS can successfully model the presence or absence of periodicity in low-amplitude light curves.
Methods. CPS computes values for the mean brightness, photometric period, amplitude and minimum of selected datasets. We also applied the Power Spectrum Method (PSM) to these datasets and compared the performance of this frequently applied method to that of CPS.
Results. We found an apparent 11.7 ± 0.5 yr cycle in the mean brightness. The mean of the individual photometric rotation periods is 7.24 ± 0.22 days. The lower limit for the differential rotation coefficient is |k| \u3e 0.12, assuming that period changes in V352 CMa follow the solar pattern. The Kuiper method detected stable, active longitudes rotating with a period of 7.157 ± 0.002 days, from the epochs of light minimum, but these structures vanished after the year 2009. CPS performed better than the traditional PSM, because the latter assumes a sinusoidal model for the data even when this was not correct
Suicides and deaths linked to risky health behavior in childhood cancer patients : A Nordic population-based register study
Background Childhood cancer survivors have been reported to be vulnerable to psychiatric morbidities and risky health behavior. Suicides, substance abuse, accidents, and violence as causes of death can be regarded as an extreme manifestation of risky health behavior. In the current study, the authors studied the risk of suicide and other risky health behavior-related deaths among childhood cancer patients in Denmark, Finland, and Sweden. Methods Using linkage between national cancer, population, and cause-of-death registries, the authors investigated the causes of death in 29,285 patients diagnosed with cancer before age 20 years between 1971 and 2009 compared with a cohort of 146,282 age-matched, sex-matched, and country-matched population comparisons. Rate ratios (RRs) with 95% CIs were estimated using Poisson regression models, adjusting for demographic factors. Results The overall risk of dying of a risky health behavior was found to be increased among childhood cancer patients (RR, 1.25; 95% CI, 1.06-1.47) when compared with population comparisons. The elevated risk was statistically significant among patients with central nervous system tumors (RR, 1.49; 95% CI, 1.08-2.05) and patients diagnosed at ages 5 to 9 years and 15 to 19 years (RR, 1.50 [95% CI, 1.01-2.24] and RR, 1.31 [95% CI, 1.03-1.67], respectively). The overall risk of suicide was found to be increased (RR, 1.37; 95% CI, 1.02-1.83), and statistically significantly so when patients were diagnosed between ages 15 and 19 years (RR, 1.61; 95% CI, 1.09-2.39). Conclusions Childhood cancer patients appear to have an increased risk of risky health behavior-related causes of death compared with the general population. The results of the current study suggest the importance of integrating psychosocial support into the follow-up care of these individuals.Peer reviewe
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Multiple-instrument polyphonic music transcription using a temporally constrained shift-invariant model
A method for automatic transcription of polyphonic music is proposed in this work that models the temporal evolution of musical tones. The model extends the shift-invariant probabilistic latent component analysis method by supporting the use of spectral templates that correspond to sound states such as attack, sustain, and decay. The order of these templates is controlled using hidden Markov model-based temporal constraints. In addition, the model can exploit multiple templates per pitch and instrument source. The shift-invariant aspect of the model makes it suitable for music signals that exhibit frequency modulations or tuning changes. Pitch-wise hidden Markov models are also utilized in a postprocessing step for note tracking. For training, sound state templates were extracted for various orchestral instruments using isolated note samples. The proposed transcription system was tested on multiple-instrument recordings from various datasets. Experimental results show that the proposed model is superior to a non-temporally constrained model and also outperforms various state-of-the-art transcription systems for the same experiment
Microelectrode Array With Transparent ALD TiN Electrodes
Low noise platinum black or sputtered titanium nitride (TiN) microelectrodes are typically used for recording electrical activity of neuronal or cardiac cell cultures. Opaque electrodes and tracks, however, hinder the visibility of the cells when imaged with inverted microscope, which is the standard method of imaging cells plated on microelectrode array (MEA). Even though transparent indium tin oxide (ITO) electrodes exist, they cannot compete in impedance and noise performance with above-mentioned opaque counterparts. In this work, we propose atomic layer deposition (ALD) as the method to deposit TiN electrodes and tracks which are thin enough (25–65 nm) to be transparent (transmission ∼18–45%), but still benefit from the columnar structure of TiN, which is the key element to decrease noise and impedance of the electrodes. For ALD TiN electrodes (diameter 30 μm) impedances from 510 to 590 kΩ were measured at 1 kHz, which is less than the impedance of bare ITO electrodes. Human induced pluripotent stem cell (hiPSC)-derived cortical neurons were cultured on the ALD TiN MEAs for 14 days without observing any biocompatibility issues, and spontaneous electrical activity of the neurons was recorded successfully. The results show that transparent ALD TiN film is a suitable electrode material for producing functional MEAs
Search for intracranial aneurysm susceptibility gene(s) using Finnish families
BACKGROUND: Cerebrovascular disease is the third leading cause of death in the United States, and about one-fourth of cerebrovascular deaths are attributed to ruptured intracranial aneurysms (IA). Epidemiological evidence suggests that IAs cluster in families, and are therefore probably genetic. Identification of individuals at risk for developing IAs by genetic tests will allow concentration of diagnostic imaging on high-risk individuals. We used model-free linkage analysis based on allele sharing with a two-stage design for a genome-wide scan to identify chromosomal regions that may harbor IA loci. METHODS: We previously estimated sibling relative risk in the Finnish population at between 9 and 16, and proceeded with a genome-wide scan for loci predisposing to IA. In 85 Finnish families with two or more affected members, 48 affected sibling pairs (ASPs) were available for our genetic study. Power calculations indicated that 48 ASPs were adequate to identify chromosomal regions likely to harbor predisposing genes and that a liberal stage I lod score threshold of 0.8 provided a reasonable balance between detection of false positive regions and failure to detect real loci with moderate effect. RESULTS: Seven chromosomal regions exceeded the stage I lod score threshold of 0.8 and five exceeded 1.0. The most significant region, on chromosome 19q, had a maximum multipoint lod score (MLS) of 2.6. CONCLUSIONS: Our study provides evidence for the locations of genes predisposing to IA. Further studies are necessary to elucidate the genes and their role in the pathophysiology of IA, and to design genetic tests
Localism in Finland : The changing role and current crisis of the Finnish municipal system
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