Косова, А. Л. Chronotype, sleep length, and school achievement of 11- to 23-year-old students in northern European Russia / Borisenkov M. F., Perminova E. V., Kosova A. L. // Chronobiol. Int. - 2010. - Vol. 27. - P. 1259-1270.

Chronobiol Int Downloaded from informahealthcare.com by 217.66.146.98 on 07/23/10 For personal use only. 1262 M. F. Borisenkov et al. FIGURE 1 Geographical coordinates of the surveyed population groups of northern European Russia. Numbers indicate settlements: 1 = villages in the south of KR; 2 = Syktyvkar; 3 = Inta; 4 = Apatity. The blank map is taken from http://atlas.edu.ru. Subjects and Data Collection The sample of students interviewed (N = 1101 in total) involved 655 girls and 446 boys age 11 to 23 yrs (mean ± SD: 16.1 ± 3.1). The survey was conducted anonymously and voluntarily among school children and TABLE 1 Characteristics of settlements Parameter Settlements 1 2 3 4 Dates of investigation 05-06.05.09 10-26.03.09 18-23.03.09 18-21.03.09 School schedule, days/wk 6 6 6 6 School start time, h 8.5 8-8.25 8.33-8.5 8.5-9 Population 1,000 250,000 40,000 60,000 Settlement status Villages City City City Latitude, degrees North 59.28 61.42 66.02 6V.34 Longitude, degrees East 49.36 50.51 60.08 33.23 Time of sunrise,0 h 4.5-1.53 5.32-6. IV 4.82-5.13 4.93-5.13 Day length, h 16.24-16.3 11.25-12.8 12.02-12.6 12.02-12.39 Ave. annual temperature, °C + 1 + 0.5 -4.5 -4.5 Longest days,6 h (day/mo) 18.68 (22/06) 19.6 (22/06) 24 (12-29/06) 24 (30/05-15/07) Shortest days, h (day/mo) 6.03 (22/12) 5.2V (22/12) 2.V3 (22/12) 0 (16-28/12) Note. Settlements: 1 = villages in the south of KR; 2 = Syktyvkar, KR; 3 = Inta, KR; 4 = Apatity, MR. aAt days of investigation. Day length (day/mo). Geographical coordinates of regions of investigation are determined by means of www.satsig.net/ maps/lat-long-finder.htm. Time of sunrise calculated by means of http://aa.usno.navy.m il/data/ docs/ RS_OneDay.php n i Q H T f l L i 14 H*> H I'll г Iiti I 'рі-г гі і 1 - г ■r ■