We present a statistical analysis of a complete sample (255) of northern planetary nebulae (PNe). Our analysis is based on morphology as a main parameter. The major morphological classes are: round (26% of the sample), elliptical (61 %), and bipolar (13 %) PNe. About a half of the round and 30 % of the elliptical PNe present multiple shells. Round PNe have higher galactic latitude (|b| =12) and...

We use digitized Schmidt direct and prism plates taken for the northern hemisphere Hamburg Quasar Survey (HQS) to obtain optical identifications for all high galactic latitude X-ray sources in the ROSAT Bright Source Catalogue (RASS-BSC) at |b| ≥ 30 • and δ ≥ 0 •. In this part of the sky the RASS-BSC contains about 5300 X-ray sources. Presently, identifications exist for ∼ 4100 RASS-BSC sources...

BACKGROUND Age at menarche is considered a reliable prognostic factor for idiopathic scoliosis and varies in different geographic latitudes. Adolescent idiopathic scoliosis prevalence has also been reported to be different in various latitudes and demonstrates higher values in northern countries. A study on epidemiological reports from the literature was conducted to investigate a possible asso...

6 Many climate models are unable to capture the magnitude of observed warming and sea ice 7 decline in high northern latitudes. To understand the factors affecting the simulated warming 8 we compare the response to increasing CO2 in two pairs of climate models by decomposing 9 the 40–90◦N region heat budget. Each pair includes a member with enhanced global and 10 northern high latitude surface ...

The impact of latitude on sleep duration remains virtually unexplored, even though latitude exerts profound influences on daylight duration. Using Chile as a one-country model, we explored on the potential associations between sleep duration and latitude. Based on the 2nd Chilean Health Survey, we identified reported sleep data during spring of people living from north to south in Chilean citie...