Safety I–II,resilience and antifragility engineering: a debate explained through an accident occurring on a mobile elevating work platform

Occupational health and safety (OHS) represents an important field of exploration for the research community: in spite of the growth of technological innovations, the increasing complexity of systems involves critical issues in terms of degradation of the safety levels. In such a situation, new safety management approaches are now mandatory in order to face the safety implications of the current technological evolutions. Along these lines, performing risk-based analysis alone seems not to be enough anymore. The evaluation of robustness, antifragility and resilience of a socio-technical system is now indispensable in order to face unforeseen events. This article will briefly introduce the topics of Safety I and Safety II, resilience engineering and antifragility engineering, explaining correlations, overlapping aspects and synergies. Secondly, the article will discuss the applications of those paradigms to a real accident, highlighting how they can challenge, stimulate and inspire research for improving OHS conditions.     

GC-EAG-analysis of volatiles from Brussels sprouts plants damaged by two species of Pieris caterpillars: olfactory receptive range of a specialist and a generalist parasitoid wasp species

Summary. Feeding by Pieris brassicae or P. rapae caterpillars on Brussels sprouts plants induces the emission of synomones that attract natural enemies of the caterpillars, Cotesia glomerata, a generalist parasitoid, and C. rubecula, a specialist on P. rapae. Previous research on this tritrophic system has identified a large number of volatiles in the headspace of herbivore-damaged Brussels sprouts plants, and this paper addresses the question which of these volatiles are perceived by the two parasitoid species. Headspace odors from both P. brassicae- and P. rapae-damaged Brussels sprouts plants were analyzed by coupled gas chromatography electro- antennogram (GC-EAG) detection. Twenty volatiles evoked consistent EAG reactions in the antennae of both species and nineteen of these volatiles could be identified with GC-MS. One component that could not be identified due to its low concentration, evoked EAG responses in antennae of C. rubecula only. Possible consequences for searching behavior of the two parasitoid species are discussed.     

Population ecology of the green/black turtle (<Emphasis Type="Italic">Chelonia mydas</Emphasis>) in Bahía Magdalena,Mexico

The mangrove channels of Bahía Magdalena, Mexico, are important developmental areas for juvenile green, or black turtles (Chelonia mydas), but incidental bycatch and illegal hunting threaten population persistence. We studied size distribution, condition index (CI), growth rates, and mortality of black turtles in Estero Banderitas, the largest mangrove channel in Bahía Magdalena, to supply information for the development of effective conservation strategies. A total of 213 black turtles (including 88 recaptures) were caught in entanglement nets between July 2000 and July 2003. Average yearly catch per unit of effort (CPUE, 1 unit: 100 m of net fishing for 12 h) dropped during the study from 2.19 to 0.76. About 97% of all turtles were considered juveniles, average size was 54.6 ± 9.5 cm. Turtles were significantly smaller at the head of Estero Banderitas than in the central part of the Estero and in the open bay, indicating size-based habitat segregation. Average growth rate was 1.62 cm/year and declined with increasing size. Growth was seasonal and three times higher in summer (0.28 cm/month) than in winter (0.09 cm/month), body CI was also significantly higher during the summer months. A seasonalized von Bertalanffy growth function (VBGF) was used to model growth for the size range studied (43–73 cm SCL), with the parameters: L _∞ = 101 cm SCL; K = 0.04 year⁻¹; t ₀ = 0; C = 0.4 and t _s = 0.75. Growth data indicate that black turtles may spend up to 20 years in Bahía Magdalena before they reach maturity at about 77 cm SCL. The total mortality estimate (Z) from the length converted catch curve was 0.16, corresponding to a yearly survival probability of 0.85.     

Density,size structure and aspergillosis prevalence in <Emphasis Type="Italic">Gorgonia ventalina</Emphasis> at six localities in Puerto Rico

Gorgonia ventalina’s density, size structure and lesion prevalence was measured at six sites in Puerto Rico that exhibited variation in horizontal water transparency, sedimentation rates, suspended particle matter, scleractinian and macroalgal cover. G. ventalina density varied significantly among sites (between 0.84 and 0.007 colonies/m²), and was positively correlated with water transparency. Size structure did not vary much among sites, and reflects high mortality among the smaller size classes and high survivorship in large colonies. Prevalence of active fungi-induced lesions (type I) did not vary significantly among sites and was density-independent. However, prevalence of old lesions of unknown origin (type II) did vary among reefs and was negatively correlated with water transparency. Prevalence of types I or II lesions was independent of colony size. Our results suggest that (1) turbidity and sedimentation are important abiotic factors controlling the abundance of sea fans, (2) variation in settlement success and early survivorship of recruits has more impact on the sea fan populations than variation in the survivorship of large colonies and (3) prevalence of aspergillosis (type I) at the studied sites is similar to that reported for other Caribbean reefs and supports the epizootic nature of the disease and (4) lesions with exposed skeleton are more likely to be colonized by fouling organisms at impacted reefs. The combined effects of anthropogenic impacts and aspergillosis may cause local extinctions of sea fans, as is becoming evident in many reefs in Puerto Rico.     

Foraging responses of wild house mice to accumulations of conspecific odor as a predation risk

Many predators hunt using the social and waste odors of their prey. It is unknown, however, whether potential prey modify their behavior in response to the risks of predation associated with accumulations of conspecific odor. We examined this question by measuring foraging trade-offs of wild house mice (Mus domesticus) in the field where we increased both predation risk and conspecific odor at artificial food patches in a two-factor design. Mouse giving-up densities (GUDs) were significantly higher in open habitats than in closed habitats but did not differ with the addition of mouse odors. Fine-scale behavioral observations of captive mice confirmed their attraction to the conspecific odor in an enclosure experiment, without any change to the GUD. These results indicate that house mice continue to visit and forage at food patches despite accumulations of predator-attracting odors. This most likely occurs for the social benefits obtained from conspecific odor exploration; however, such behavior may cause mice to become vulnerable to considerable olfactory exploitation by their predators. Future work must therefore focus on how mice trade off the social benefits of investigating odors that also attract their enemies.     

Physiological capacity and environmental tolerance in two sandhopper species with contrasting geographical ranges: Talitrus saltator and Talorchestia ugolinii

We investigated the physiological plasticity and environmental tolerance of two phylogenetically closely related, ecologically similar and co-occurring species of supralittoral amphipods differing drastically in the size of their geographical ranges. A series of physiological traits were characterised for the Corsican-endemic Talorchestia ugolinii Bella-Santini and Ruffo and the widespread Talitrus saltator Montagu. The effect of body mass, temperature and salinity on heart rate (used as proxy for metabolic activity and stress), the effect of temperature on oxygen consumption and the tolerance to salinity exposure were investigated in both species, together with the characterisation of haemolymph osmoregulation in T. ugolinii. Our results showed that there is a clear difference in the resting metabolic rates and physiological capacity, as well as environmental tolerance, between T. saltator and T. ugolinii, with T. saltator overall showing a broader physiological niche. Although T. ugolinii showed a relatively good ability to regulate its haemolymph osmotic concentration (similar to that previously described for T. saltator), it demonstrated a lower tolerance to exposure to hypo-osmotic stress. In addition, a consistent picture emerged between the ability to control the cardiac function and the capacity to actively respond to osmotic stress. The physiological findings are discussed in relation to the known ecology and geographical distribution of T. ugolinii.     

Comparative feeding ecology of felids in a neotropical rainforest

Summary Diet and habitat use of jaguar, puma, and ocelot, and populations of their mammalian prey, were studied in an undisturbed rainforest in southeastern Peru. Analysis of scats (feces) showed terrestrial mammals to be the chief prey of all three felids, but reptiles and birds were also numerically important in the diets of ocelot and jaguar. Prey diversity is high and the cats evidently take any readily captured vertebrate. For major terrestrial mammal prey of felids, density, biomass, prey/predator ratios, and annual offtake from the study area are estimated. All three cat species seem to hunt by opportunistic encounter of prey. Most mammalian prey species were taken in about the ratios of occurrence, but peccaries were taken by jaguar more often than expected. Most prey of jaguar have a body weight of >1 kg, those of ocelot, 1 kg. Jaguar often used waterside habitats, where they captured caiman and river turtles. Puma did not use these habitats or resources, although the puma prey sample was too small for much inference. The possible effects of felids on study area prey populations are discussed. Large and small cats partition prey at the body weight region where prey switches from low to high reproductive rates.     

Chemistry of the postpharyngeal gland secretion and its implication for the phylogeny of IberianCataglyphis species (Hymenoptera: Formicidae)

Summary A comparative morphological and chemical study of six endemic species ofCataglyphis from the Iberian Peninsula:C. ibericus, C. rosenhaueri, C. hispanicus, C. humeya, C. velox andC. floricola and the Moroccan speciesC. bombycinus is described. The morphological study relied primarily on genitalia characteristics, whereas the chemical study concentrated on the postpharyngeal gland constituents. Cladograms based on the morphological and chemical data were performed using Ward's method. The dendrogram based on morphological features revealed that the IberianCataglyphis can be classified into three species groupsalbicans, altisquamis andemmae. The same pattern occurred when the dimethylalkanes constituents of the postpharyngeal gland were utilised as character states, with a slight displacement of species within thealtisquamis group. However, when the complete hydrocarbon blend was utilised major discrepancies in the dendrograms occurred.Cataglyphis velox proved to be very similar toC. bombycinus, whereasC. floricola clustered with the other two species of thealtisquamis group. Based on the geographical distribution and paleontological data (Tinaut 1993) it is assumed thatC. floricola recently invaded the Iberian Peninsula. Based on the chemical findings we postulate that chemical character displacement occurred inC. floricola as a result of its sympatry withC. velox after the former colonized the Iberian Peninsula. We further discuss the possible reason for the different dendrograms obtained when only the dimethylalkanes are considered and its implication for the communicative role of the postpharyngeal gland secretion in these ants.