Kyiv — On a bitterly cold Wednesday in Kyiv's Heroiv Dnipra neighborhood, Mariana Kiriluk, a foot doctor in her late-thirties, didn't know what to do with her ten-year-old son Zahar. Schools in the Ukrainian capital are closed until February, as Russian strikes have knocked out power to half of the city. As for thousands of other families, the power outages also mean it's bitterly cold for Zahar and his mother, with temperatures dipping below five degrees Fahrenheit.  "Sometimes I take him to