Seasonal patterns of polycyclic aromatic hydrocarbons in digestive gland and arm of octopus (Octopus vulgaris) from the Northwest Atlantic

Among organic pollutants existing in coastal areas, polycyclic aromatic hydrocarbons (PAHs) are of great concern due to their ubiquity and carcinogenic potential. The aim of this study was to evaluate the seasonal patterns of PAHs in the digestive gland and arm of the common octopus (Octopus vulgaris) from the Northwest Atlantic Portuguese coast. In the different seasons, 18 PAHs were determined and the detoxification capacity of the species was evaluated. Ethoxyresorufin O-deethylase (EROD) and ethoxycoumarin O-deethylase (ECOD) activities were measured to assess phase I biotransformation capacity. Individual PAH ratios were used for major source (pyrolytic/petrogenic) analysis. Risks for human consumption were determined by the total toxicity equivalence approach. Generally, low levels of PAHs were detected in the digestive gland and in the arm of octopus, with a predominance of low molecular over high molecular weight compounds. PAHs exhibited seasonality in the concentrations detected and in their main emission sources. In the digestive gland, the highest total PAH levels were observed in autumn possibly related to fat availability in the ecosystem and food intake. The lack of PAH elimination observed in the digestive gland after captivity could be possibly associated to a low biotransformation capacity, consistent with the negligible/undetected levels of EROD and ECOD activity in the different seasons. The emission sources of PAHs found in the digestive gland varied from a petrogenic profile observed in winter to a pyrolytic pattern in spring. In the arm, the highest PAH contents were observed in June; nevertheless, levels were always below the regulatory limits established for food consumption. The carcinogenic potential calculated for all the sampling periods in the arm were markedly lower than the ones found in various aquatic species from different marine environments. The results presented in this study give relevant baseline data for environmental monitoring of organic pollution in coastal areas.

How Effective are Unemployment Benefit Sanctions? Looking Beyond Unemployment Exit

This paper provides a comprehensive evaluation of the effects of benefit sanctions on post-unemployment outcomes such as post-unemployment employment stability and earnings. We use rich register data which allow us to distinguish between a warning that a benefit reduction may take place in the near future and the actual withdrawal of unemployment benefits. Adopting a multivariate mixed proportional hazard approach to address selectivity, we find that warnings do not affect subsequent employment stability but do reduce post-unemployment earnings. Actual benefit reductions lower the quality of post-unemployment jobs both in terms of job duration as well as in terms of earnings. Copyright © 2012 John Wiley & Sons, Ltd.

"Public on the outside, private on the inside": the organizational hybridization, sense of belonging and identity strategies of the employees of a public unemployment insurance fund in Switzerland

A number of studies show that New Public Management reforms have altered the current identity benchmarks of public officials, particularly by hybridizing values or management practices. However, existing studies have largely glossed over the sense of belonging of officials when their organization straddles the concerns of public service and private enterprise, so that the boundary between public and private sector is blurred. The purpose of this article is precisely to explore this sense of belonging in the context of organizational hybridization. It does so by drawing on the results of research conducted among the employees of a public unemployment insurance fund in Switzerland. On the one hand, the analysis shows how much their markers of belonging are hybrid, multiple and constructed in negative terms (with regard to the State), while indicating that the working practices of the employees point to an identity that is nevertheless closely bound with the public sector. On the other hand, the analysis shows that the organization plays strategically with its State status, by exploiting either its private or public identity in line with the needs related to its external image. The article concludes with a discussion of the results highlighting the strategic functionality of the hybrid identity of the actors.

Seasonal changes in behavioural and thermoregulatory responses to hypoxia in the Eastern Chipmunk (Tamias striatus) /

Mammalian heterotherms, such as hibemators, are known to be more tolerant of low oxygen tensions than their homeothermic counterparts. It has been suggested that this relative hypoxia tolerance is related to their ability to deal with dramatic changes in body temperature during entry to and arousal from torpor. However, hibemators demonstrate dramatic seasonality in both daily heterothermy and overall torpor expression. It was of interest to test if seasonal comparisons of normothermic individuals within a single species with the capacity to hibernate produce changes in the response to hypoxia that would reflect a seasonal change in tolerance to low oxygen. In particular, the species studied, the Eastern chipmunk {Tamias striatus), is known to enter into torpor exclusively in the winter. To test for seasonal differences in the metabolic and thermoregulatory responses to hypoxia, flow-through respirometry was used to compare metabolic rate, minimum thermal conductance, body temperature, and a thermal gradient used to assess selected ambient temperature in response to hypoxia in both summer and winter acclimated animals. Although the animals periodically expressed torpor throughout the winter, no differences between season in resting metabolic rate, body temperature or minimum thermal conductance were observed in normoxia. The metabolic trials indicated that chipmunks are less responsive to hypoxia in the winter than they are in the summer. Although body temperature dropped in response to hypoxia in both seasons, the decrease was less in the winter, and there was no corresponding decrease in metabolic rate. Providing the animals with a choice of ambient temperatures in hypoxia resulted in a blunting of the drop in body temperature in both seasons, suggesting that the reported fall in body temperature set point in hypoxia is not fully manifested in the behavioural pathways responsible for thermoregulation in chipmunks. Instead, body temperature in hypoxia appears to be highly dependent on ambient temperature and oxygen concentration. The results of this study suggest that the season in which the responses to hypoxia are measured is important, especially in a heterotherm where seasonality can affect the degree to 1 which the animal is tolerant of hypoxia. Winter-acclimated chipmunks appear more capable of defending metabolic heat production in hypoxia, a response consistent with the increased thermogenic capacity observed in animals that must periodically enter and arouse from torpor during hibernation.

Mermithid (nematoa: mermithidae) infections of black flies (Diptera: Simuliidae) : seasonal variation and developmental characteristics /

Mermithid nematodes (Nematoda: Mermithidae) parasitize larval, pupal and adult black flies (Diptera: Simuliidae), oftentimes resulting in partial or complete host feminization. This study was designed to characterize parasite-host seasonal variation and to estabUsh the developmental life stage at which feminization is initiated. Data indicate that the total adult population of black flies collected from Algonquin Provincial Park throughout the spring of 2004 was comprised of 31.8% female, 67.8% male and 0.4% intersex individuals. Of the total population, 0.6% was infected by mermithid nematodes (69.0% female, 3.5% male and 27.6% intersex). Seasonal infection trends established over a 12-month period revealed that black flies with different life histories host the same mermithid subfamilies, while black flies with similar life histories host mermithids from different subfamilies. If a simuliid species simultaneously hosts two mermithid species, these parasites are from different subfamilies. Molecular mermithid identification revealed two mermithid subfamilies, Me.somermithinae and Gastromermithinae, present in the simuliid hosts. Mermithid colour variation was not found to be a reliable species indicator. The developmental stage at which feminization is initiated was determined by examining gonad morphology and meiotic chromosomal condition. Results indicate that mermithid-infected black flies exhibit feminization prior to larval histoblast formation. Larvae can be morphologically male (testes present) or female (ovaries present), with morphological males exhibiting either male (achiasmate) or female (chiasmate) meiotic chromosomes; morphological females were only genetically female. Additionally, mermithid infection inhibits simuliid gonad development.

Factors influencing the seasonal changes in primary productivity of the photosynthetic bacteria of Crawford Lake, Ontario

A naturally occurring population of photosynthetic bacteria, located in the meromictic Crawford Lake, was examined during two field seasons (1979-1981). Primary production, biomass, light intensity, lake transparency, pH and bicarbonate concentration were all monitored during this period at selected time intervals. Analysis of the data indicated that (l4C) bacterial photosynthesis was potentially limited by the ambient bicarbonate concentration. Once a threshold value (of 270 mg/l) was reached a dramatic (2 to 10 fold) increase in the primary productivity of the bacteria was observed. Light intensity appeared to have very little effect on the primary productivity of the bacteria, even at times when analyses by Parkin and Brock (1980a) suggested that light intensity could be limiting (i.e., 3.0-5.0 ft. candles). Shifts in the absorption maxima at 430 nrn of the .bacteriochlorophyll spectrum suggested that changes in the species or strain composition of the photosynthetic bacteria had occurred during the summer months. It was speculated that these changes might reflect seasonal variation in the wavelength of light reaching the bacteria. Chemocline erosion did not have the same effect on the population size (biomass) of the photosynthetic bacteria in Crawford Lake (this thesis) as it did in Pink Lake (Dickman, 1979). In Crawford Lake the depth of the chemocline was lowered with no apparent loss in biomass (according to bacteriochlorophyll data). A reverse current was. proposed to explain the observation. The photosynthetic bacteria contributed a significant proportion (10-60%) of the lake1s primary productivitya Direct evidence was obtained with (14C) labelling of the photosynthetic bacteria, indica.ting that the zooplankton were grazing the photosynthetic bacteria. This indicated that some of the photosynthetic bacterial productivity was assimilated into the food chain of the lake. Therefore, it was concluded that the photosynthetic bacteria made a significant contribution to the total productivity of Crawford Lake.

Seasonal variation in the reproductive biology of the ring -billed gull (Larus delawarensis)

The reproductive biology of the Ring-billed Gull (Larus delawarensis) was studied on Gull Island, Presqu'ile Provincial Park, Ontario, in 1976 and 1977. Early started clutches (comprising the majority of clutches on Gull Island) in 1977 produced more chicks per nest (2.20 ± 0.09) than late started clutches (0.86 ± 0.13) as a result of reductions in mean clutch size, hatching success and fledging success with date of clutch initiation. Seasonal changes in mean clutch size, hatching success and fledging success also resulted in early clutches, initiated at the peak of clutch starts, producing more chicks per nest (2.34 ± 0.11) than either pre-peak (2.13 ± 0.20) or post-peak (1.82 ± 0.29) clutches. Possible reasons for these trends, including the observed predominance of immature plumaged, breeding gulls in late started areas, are discussed. Clutches were deserted at night for varying lengths of time from at least 15 April until 10 May, 1977. It is suggested that this nocturnal desertion behaviour resulted in the enhancement of inter- and intra-clutch hatching synchrony in early started areas and further, that this may in part explain the existence of the behaviour in terms of its adaptive significance.

Seasonal variation in hatching pattern and chick survival in the ring-billed gull Larus delawarensis

The general objective of my study was to monitor proximate causes and seasonal patterns of hatching asynchrony and chick survival in the Ring-billed Gull (Larus delawarensis). Two different plots were set up at a Ring-billed Gull colony near Port Colborne, Ontario in the summer of 1992. One group was from 'peak' nesting pairs (clutches initiated between 15 April and 1 May); a second group was from 'late' nesting pairs (clutches initiated between 9 .. 22 May). Despite equal intra-clutch egg laying intervals between the peak and late periods, intra-clutch hatching intervals lengthened as the season progressed (ie. hatching became more asynchronous). Clutches from both periods were monitored for nocturnal attendance and brood patch development of parents was monitored during the egg laying period. Late nesters were characterized by an absence of nocturnal desertion, substantial brood patch defeatheration at clutch initiation and a reduction in the number of chicks fledged per pair. Chick survival to 25 days (taken as fledging) reflected patterns of chick mass at brood completion and five days post-brood completion, in peak clutches. In late clutches, survival was poor for all chicks and, was partially independent of hatching order, due in part to stochastic events such as Herring Gull predation and adverse weather. In both the peak and late periods, last-hatched C-chicks realized the poorest survival to fledging among brood mates. An artificial hatching pattern (manipulated synchrony) and an artificial hatching order were created, in three-chick broods, through a series of egg exchanges. In peak and late clutches manipulated to hatch synchronously (s; 24 h): C-chick survival to fledging did not differ from the survival of A- and B-chicks, in the peak period. In the late period, the survival of C-chicks was significantly lower than that of A-chicks. In peak clutches manipulated such that chicks from last-laid eggs (C-chicks) hatched 24 h - 48 h ahead of the A- and B- chicks, C-chick survival was greater than in controls. Within those broods, C-chicks survived better on average than both A- and B- chicks.

Seasonal reproductive endothermy in tegu lizards

With some notable exceptions, small ectothermic vertebrates are incapable of endogenously sustaining a body temperature substantially above ambient temperature. This view was challenged by our observations of nighttime body temperatures sustained well above ambient (up to 10°C) during the reproductive season in tegu lizards (~2 kg). This led us to hypothesize that tegus have an enhanced capacity to augment heat production and heat conservation. Increased metabolic rates and decreased thermal conductance are the same mechanisms involved in body temperature regulation in those vertebrates traditionally acknowledged as “true endotherms” : the birds and mammals. The appreciation that a modern ectotherm the size of the earliest mammals can sustain an elevated body temperature through metabolic rates approaching that of endotherms enlightens the debate over endothermy origins, providing support for the parental care model of endothermy, but not for the assimilation capacity model of endothermy. It also indicates that, contrary to prevailing notions, ectotherms can engage in facultative endothermy, providing a physiological analog in the evolutionary transition to true endothermy.

The Inflation Bias When the Central Bank Targets, the Natural Rate of Unemployment

This paper studies the proposition that an inflation bias can arise in a setup where a central banker with asymmetric preferences targets the natural unemployment rate. Preferences are asymmetric in the sense that positive unemployment deviations from the natural rate are weighted more (or less) severely than negative deviations in the central banker's loss function. The bias is proportional to the conditional variance of unemployment. The time-series predictions of the model are evaluated using data from G7 countries. Econometric estimates support the prediction that the conditional variance of unemployment and the rate of inflation are positively related.