منابع مشابه
Birds do not work harder to breathe.
An efficient one-way airflow system is essential for bird flight. Extracting more oxygen per breath than mammals, birds can meet the costly fuel demands of flight. However, despite the gains achieved by maximising the amount of oxygen passing through their lungs, the metabolic cost of breathing for birds could be high. Birds were thought to have to work against the weight of their flight muscle...
متن کاملDetecting communities is Hard (And Counting Them is Even Harder)
We consider the algorithmic problem of community detection in networks. Given an undirected friendship graph G = (V, E), a subset S ⊆ V is an (α, β)-community if: • Every member of the community is friends with an α-fraction of the community; • Every non-member is friends with at most a β-fraction of the community. Arora et al [AGSS12] gave a quasi-polynomial time algorithm for enumerating all ...
متن کاملHard Times Made Harder: Struggling Caregivers and Child Neglect
• Neglected children from households with caregivers who struggle with drug use were three times as likely to be placed in out-ofhome care than those without drug problems. • Neglected children who lived with caregivers with mental health problems, alcohol problems, or who had trouble paying for basic necessities were about twice as likely to be placed in out-ofhome care. • Neglected children i...
متن کاملWork Hard, Party Harder: Drug Use and Sexual Behaviour in Young British Casual Workers in Ibiza, Spain
BACKGROUND Every summer, young people flock to nightlife-focused holiday resorts around the world to find casual work. Despite being exposed to hedonistic environments, often for several months, little is known about their substance use, sexual activity and health service needs over this extended amount of time abroad. METHODS A short anonymous questionnaire examining alcohol and drug use, se...
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ژورنال
عنوان ژورنال: Canadian Medical Association Journal
سال: 2008
ISSN: 0820-3946,1488-2329
DOI: 10.1503/cmaj.081414