Time derivative of the horizontal geomagnetic field as an activity indicator

Time derivative of the horizontal geomagnetic field as an activity indicator

Geomagnetically induced currents (GICs) in technological conductor systems are a manifestation of the ground effects of space weather. Large GICs are always associated with large values of the time derivative of the geomagnetic field, and especially with its horizontal component (dH/dt). By using the IMAGE magnetometer data from northern Europe from 1982 to 2001, we show that large dH/dt’s (exc...

Horizontal-Branch Morphology as an Age Indicator

We present our recent revision of model constructions for the horizontal-branch (HB) morphology of globular clusters, which suggests the HB morphology is more sensitive to age compared to our earlier models. We also present our high precision CCD photometry for the classic second parameter pair M3 and M13. The relative age dating based on this photometry indicates that M13 is indeed older than ...

Nonlinear time series analysis of the fluctuations of the geomagnetic horizontal field

A detailed nonlinear time series analysis of the hourly data of the geomagnetic horizontal intensity H measured at Kodaikanal (10.2 N; 77.5 E; mag: dip 3.5 N) has been carried out to investigate the dynamical behaviour of the fluctuations of H . The recurrence plots, spatiotemporal entropy and the result of the surrogate data test show the deterministic nature of the fluctuations, rejecting the...

The geomagnetic field variations and earthquake activity

Horizontal sacrum as an indicator of a tethered spinal cord.

The horizontal sacrum has never been described as an indicator of a tethered spinal cord following myelomeningocele closure. We retrospectively analyzed 30 children with a myelomeningocele for this progressive change and its correlation with symptoms. At least two lateral radiographs over time were examined and the lumbosacral angle (LSA) was measured. We found that the majority of these childr...