Recolonization by wolves (Canis lupus) of areas of extensive sheep breeding in the French Alps in the early 1990s led to intense conflicts over losses of domestic livestock. We used data on depredations and sheep herd management from 45 pastures of the Mercantour Mountains of the French Alps to build models of attack and kill rates and to quantify the efficiency of using livestock‐guarding dogs and of gathering or confining herds at night to prevent damage. Efficiency of livestock‐guarding dogs was lowest when sheep were ranging freely and highest when sheep were confined at night. The effect of livestockguarding dogs on depredations was heterogeneous across pastures. When sheep were confined at night, presence of 3 to 4 dogs was predicted to prevent a large majority (>95%) of kills that would have occurred in the absence of dogs for 81% of pastures. No effect of dogs was found for the other 19% of pastures. Confining or simply gathering sheep at night in the presence of 5 livestock‐guarding dogs was predicted to prevent most kills (94% and 79%, respectively) that would have occurred in similar conditions but with free‐ranging sheep. Efficiency of each of these 2 techniques was drastically reduced when they were not used jointly. This study suggested that confining sheep in the presence of several livestock‐guarding dogs can prevent a large majority of livestock losses to wolves in the southern French Alps.

The presence of stratum corneum carbonyls may serve as an intrinsic dosimeter for environmental oxidative damage to skin. To investigate the accumulation of carbonyls in human stratum corneum, skin was tape-stripped, then tapes were sequentially incubated with 2,4-dinitrophenyl hydrazine (DNPH), rat anti-DNP, mouse anti-rat IgG conjugated with alkaline phosphatase, p-nitrophenyl phosphate and absorbance (405 nm) measured and carbonyls estimated. Stratum corneum exposed in vitro to oxidants: hypochlorous acid (1, 10, 100 mM), ozone (0, 1, 5, 10 ppm for 2 h) or UV light (280^400 nm; 0, 4, 88, or 24 J/cm P ) contained increased carbonyls. Furthermore, stratum corneum carbonyls were elevated in tanned compared with untanned sites: dorsal hand (0.43 þ 0.06 nmol/cm P ) vs. lower arm (0.32 þ 0.04, mean þ S.E.M., n = 11; P 6 0.003) and lower back (0.26 þ 0.02) vs. buttock (0.21 þ 0.02; n = 6, P 6 0.01) indicating in vivo oxidative damage.z 1998 Federation of European Biochemical Societies.