Positive solutions of the diophantine equation

Integral solutions of x3+λy+1−xyz=0 are observed for all integral λ. For λ=2 the 13 solutions of the equation in positive integers are determined. Solutions of the equation in positive integers were previously determined for the case λ=1

Dynamics of isolated magnetic bright points derived from Hinode/SOT G-band observations

Small-scale magnetic fields in the solar photosphere can be identified in high-resolution magnetograms or in the G-band as magnetic bright points (MBPs). Rapid motions of these fields can cause magneto-hydrodynamical waves and can also lead to nanoflares by magnetic field braiding and twisting. The MBP velocity distribution is a crucial parameter for estimating the amplitudes of those waves and the amount of energy they can contribute to coronal heating. The velocity and lifetime distributions of MBPs are derived from solar G-band images of a quiet sun region acquired by the Hinode/SOT instrument with different temporal and spatial sampling rates. We developed an automatic segmentation, identification and tracking algorithm to analyse G-Band image sequences to obtain the lifetime and velocity distributions of MBPs. The influence of temporal/spatial sampling rates on these distributions is studied and used to correct the obtained lifetimes and velocity distributions for these digitalisation effects. After the correction of algorithm effects, we obtained a mean MBP lifetime of (2.50 +- 0.05) min and mean MBP velocities, depending on smoothing processes, in the range of (1 - 2) km/s. Corrected for temporal sampling effects, we obtained for the effective velocity distribution a Rayleigh function with a coefficient of (1.62 +- 0.05) km/s. The x- and y- components of the velocity distributions are Gaussians. The lifetime distribution can be fitted by an exponential function.Comment: Astronomy and Astrophysics (in press

Conditionally Helpful? The influence of Person-, Situation-, and Device-Specific Factors on Maternal Smartphone Use for Stress Coping and on Coping Effectiveness

Smartphones are omnipresent in the daily lives of parents and provide access to multiple resources in stressful situations. Thus, smartphones might be valuable coping tools. Previous research has mostly focused on the negative effects of parental phone use. In the present study, we investigated how mothers use smartphones for coping with stress and whether their phone use for coping is effective. We also explored factors on different levels (situation, person, device) which could influence phone use and coping effectiveness. Building on a one-week experience sampling study with over 200 mothers and multilevel models, we found that in stressful situations while being with children, mothers used their smartphones mostly for emotion-focused coping such as self-distraction and taking a break. Problem-focused coping was less prevalent. Mothers reporting increased cognitive phone salience used it more for coping with stress. Phone use for coping compared to no use related to lower stress decrease. No person-, situation-, or device-specific factors moderated the effects of phone use on coping effectiveness. Using positive phone content, however, was associated with increased perceived coping efficacy. Our results suggest that phone use is not generally successful for coping, but that momentary device-specific factors such as content characteristics might determine whether phones can be used for coping in an effective way

The size distribution of magnetic bright points derived from Hinode/SOT observations

Context. Magnetic Bright Points (MBPs) are small-scale magnetic features in the solar photosphere. They may be a possible source of coronal heating by rapid footpoint motions that cause magnetohydrodynamical waves. The number and size distribution are of vital importance in estimating the small scale-magnetic-field energy. Aims. The size distribution of MBPs is derived for G-band images acquired by the Hinode/SOT instrument. Methods. For identification purposes, a new automated segmentation and identification algorithm was developed. Results. For a sampling of 0.108 arcsec/pixel, we derived a mean diameter of (218 +- 48) km for the MBPs. For the full resolved data set with a sampling of 0.054 arcsec/pixel, the size distribution shifted to a mean diameter of (166 +- 31) km. The determined diameters are consistent with earlier published values. The shift is most probably due to the different spatial sampling. Conclusions. We conclude that the smallest magnetic elements in the solar photosphere cannot yet be resolved by G-band observations. The influence of discretisation effects (sampling) has also not yet been investigated sufficiently.Comment: Astronomy and Astrophysics, Volume 498, Issue 1, 2009, pp.289-29

Results from a Prospective Study of Widowhood

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142735/1/Brown-Nesse-Religion-PSPB-2004.pd

The formation and disintegration of magnetic bright points observed by Sunrise/IMaX

The evolution of the physical parameters of magnetic bright points (MBPs) located in the quiet Sun (mainly in the interwork) during their lifetime is studied. First we concentrate on the detailed description of the magnetic field evolution of three MBPs. This reveals that individual features follow different, generally complex, and rather dynamic scenarios of evolution. Next we apply statistical methods on roughly 200 observed MBP evolutionary tracks. MBPs are found to be formed by the strengthening of an equipartition field patch, which initially exhibits a moderate downflow. During the evolution, strong downdrafts with an average velocity of 2.4 km/s set in. These flows, taken together with the concurrent strengthening of the field, suggest that we are witnessing the occurrence of convective collapses in these features, although only 30% of them reach kG field strengths. This fraction might turn out to be larger when the new 4 m class solar telescopes are operational as observations of MBPs with current state of the art instrumentation could still be suffering from resolution limitations. Finally, when the bright point disappears (although the magnetic field often continues to exist) the magnetic field strength has dropped to the equipartition level and is generally somewhat weaker than at the beginning of the MBP's evolution. Noteworthy is that in about 10% of the cases we observe in the vicinity of the downflows small-scale strong (exceeding 2 km/s) intergranular upflows related spatially and temporally to these downflows.Comment: 19 pages, 13 figures; final version published in "The Astrophysical Journal

Exclusion of fish and invertebrates from benthic patches of artificial aquatic environments across water conductivity levels using high-frequency (10 Hz) pulses and adjustable electrical settings

Citation: Utz, R. M., Cooper, S. D., Gido, K. B., & Stewart, J. R. (2017). Exclusion of fish and invertebrates from benthic patches of artificial aquatic environments across water conductivity levels using high-frequency (10 Hz) pulses and adjustable electrical settings. Freshwater Science, 36(1), 151-161. doi:10.1086/690599Livestock fence chargers are often used to generate pulsed electrical fields in freshwater environments to exclude fish and invertebrates from benthic patches so that their ecological function can be investigated. Such devices appear to be effective, but the precise characteristics of the electrical fields they generate and specific settings needed to exclude organisms across water conductivity levels have not been described. We present an electrical engineering and experimental framework to predict and evaluate the effectiveness of a modified device at different combinations of electrical settings and water conductivities. We avoided toxic materials and considered safety issues. We conducted laboratory experiments to identify the electrical fields with a 10-Hz pulse frequency needed to exclude adult Fathead Minnows (Pimephales promelas) and crayfish (Procambarus clarkii) from electrical exclosures across a range of water conductivities (13-800 S/cm). Fish and crayfish in waters of low conductivity (550 S/cm) were excluded from exclosures at >= 200 V of electric potential. In water of higher conductivity (>= 250 S/cm), similar settings caused consumer immobilization. Electrical pulse durations of 150 1.ts were more effective than 50-gs pulse durations at excluding organisms. Further refinement toward standardized methods requires analogous experimentation in the field, but our findings emphasize the importance of comprehensively considering electrical fields (voltage, pulse frequency and duration), water conductivity, and electrode configuration a priori when using these devices to optimize designs

The diophantine equation r

The Diophantine equation of the title is solved in integers