Monopsony in the U.S. Labor Market

This paper quantifies the extent to which the U.S. manufacturing labor market is characterized by employer market power and how such market power has changed over time. We find that the vast majority of U.S. manufacturing plants operate in a monopsonistic environment and, at least since the early 2000s, the labor market in U.S. manufacturing has become more monopsonistic. To reach this conclusion, we exploit rich administrative data for U.S. manufacturers and estimate plant-level markdowns—the ratio between a plant’s marginal revenue product of labor and its wage. In a competitive labor market, markdowns would be equal to unity. Instead, we find substantial deviations from perfect competition, as markdowns average 1.53. This result implies that a worker employed at the average manufacturing plant earns 65 cents on each dollar generated on the margin. To investigate long-term trends in employer market power, we propose a novel measure for the aggregate markdown that is consistent with aggregate wedges and also incorporates the local nature of labor markets. We find that the aggregate markdown decreased between the late 1970s and the early 2000s, but has been sharply increasing since

Development of microsatellites for genetic analyses and population assignment of the cat flea (Siphonaptera: Pulicidae)

Cat fleas, Ctenocephalides felis (Bouch) (Siphonaptera: Pulicidae), are common ectoparasites of companion animals that negatively impact their hosts directly by causing dermatitis and blood loss during feeding and indirectly through the potential transmission of disease causing agents. We isolated and characterized seven novel microsatellite loci from a partial genomic library of the cat flea enriched for di-, tri-, and tetranucleotide repeats. We screened these loci in cat fleas from two laboratory colonies and one wild-caught population collected at a temporary animal shelter (Parker coliseum) in Baton Rouge, LA. Six loci were polymorphic, with two to 15 alleles per locus and an average observed heterozygosity of 0.21 across populations. Although the two laboratory cat flea colonies were isolated from each other for many years, they did not significantly differ in their genotypic composition. The cat flea population from Parker coliseum was genetically different from the laboratory colonies, but also showed high degrees of inbreeding. Multilocus genotypes of the polymorphic loci were sufficient to assign over 85% of cat fleas to their population of origin. Genetic markers for flea population identity will allow further studies to examine the origins and movement of cat fleas with important genetic traits such as insecticide resistance or pathogen susceptibility. The use of microsatellites also could determine if there are host-specific strains of cat fleas and add insight into the development of the different subspecies of C. felis. © 2010 Entomological Society of America

High blood levels of IL-6 nicely correlate with animal survival in trained C26 bearing mice

Exercise is a beneficial adjunct therapy to maintain or enhance quality of life in cancer patients. Recently, few studies demonstrated a correlation between high concentrations of IL-6 and a poor survival. This depends on the equilibrium between the concentrations of IL-6 and sIL-6R. Exercise induces a beneficial increase in circulating IL-6 (1). Fresh fragments of solid C26 tumor were inoculated in healthy 3 months-old mice (n=230, M=115 and F=115). The experimental procedure were 12 weeks long. During the first 6 weeks, mice were randomly assigned to one of the experimental conditions: sedentary (SED) or progressive training (TRP). After the first 6 weeks, all mice were inoculated with a fresh fragment of tumor. All trained adult mice after the tumor inoculation were randomly assigned to a different training program: low intensity training (TRL), moderate intensity training (TRM) and high intensity training (TRH). Mice run 5 days per week on a Rota-Rod following one of the specific training program (TRP ,TRL, TRM and TRH) (2). After tumor inoculation the mice were daily weighted and tumor size monitored until death. Moreover, 8 mice for each group were sacrificed when cachexia occurred (>9% body weight loss), and blood samples were stored for CBA Enhanced flex set flow-cytometric assays (IL-6 and TNF-alpha). The TRM and TRH training protocol performed by trained adult male mice extend the median survival compared to the sedentary adult mice and trained female mice. Interesting the beneficial effect of exercise seemed to be mediated extending the survival days. Significant high blood levels of IL-6 were recorded among the male trained mice (TRM and TRH) groups in comparison with sedentary adult mice and trained female mice (TRM and TRH). The results suggest that endurance exercise as adjuvant therapy is gender and physical training level specific. This effect seems to be mediated by IL-6 blood levels

Comparative microbiota of Rickettsia felis-uninfected and -infected colonized cat fleas, Ctenocephalides felis

Fleas serve as arthropod vectors for several emerging and re-emerging infectious disease causing agents including, Rickettsia felis. Although the prevalence of R. felis infection in colonies of fleas has been examined, the influence of the R. felis infection on flea microbiota has not been investigated. We identified three colonies of cat fleas, Ctenocephalides felis, with varying prevalence of R. felis infection (Louisiana State University (LSU), 93.8; Professional Laboratory and Research Services Inc. (PLRS), 16.4; Elward II (EL), 0) and subsequently utilized polymerase chain reaction amplification, restriction fragment length polymorphism analysis and sequencing of the 1.4-kb portions of 16S rRNA genes to examine the diversity of bacteria in the flea populations. A total of 17 different bacterial 16S rRNA gene sequences were identified among the C. felis colonies. The prevalence of two Wolbachia species that were identified in each flea colony differed between colonies and R. felis-uninfected and -infected fleas. Species richness was unchanged among the R. felis-uninfected (LSU, PLRS and EL colonies) and -infected (LSU and PLRS colonies) fleas; however, between R. felis-uninfected and -infected fleas within both the LSU and PLRS colonies, R. felis-uninfected fleas have greater species richness. Diversity indices did not identify a difference in diversity between any of the flea samples. The interaction of endosymbionts within arthropods can widely impact the dissemination of vertically transmitted pathogenic bacteria; and the reciprocal may be true. These results suggest that carriage of R. felis has an impact on the richness of flea microbiota. © 2007 International Society for Microbial Ecology All rights reserved

Cardiac filariosis in migratory Mute swans (Cygnus olor) in Sicily

Sarconema eurycerca is a common parasitic disease of North America swans and geese. The infection has been correlated with severe heart lesions, often resulting in cardiac failure and death of the animals. Heartworms infections have been previously reported in European swans, and specifically in the United Kingdom and Nederland. Both the countries are characterized by a cold temperate weather, similar to the one that can be found in swan wintering areas of U.S.A. and Canada. The first record of cardiac filariasis associated with Sarconema eurycerca infection in four swans in Italy. Twelve mute swans were examined during avian influenza surveillance activities on migratory birds. Birds were collected in the year 2006, in wintering areas of Eastern Sicily (Italy). Four of the twelve swans showed necrotic-haemorrhagic myocarditis with intra-lesional nematodes. Morphological characteristics identified the parasite as a filarial nematode. Birds lungs samples were used for parasites DNA extraction. The latter was used as template for polymerase chain reaction (PCR) amplification and sequencing of part of the 12S rDNA gene. Comparison of genomic DNA extracted from a reference S. eurycerca isolate confirmed parasite identity and provided the first sequence resources for this species of value to future diagnostic and epidemiological studies

An extreme negative sea level in the Mediterranean Basin: San Giorgio case study compared with Adriatic Sea

The aim of this paper is to discuss the case of an extreme negative sea level phenomenon that occurred along Sicily Island’s coasts (Italy). Sea level time series associated to six stations that are part of the Italian tide gauge network have been analysed. By deriving the tidal residual and by evaluating meteorological parameters’ trends, it was possible to give an explanation to this phenomenon

Hsp60 and interleukins expression in the skeletal muscle and its implications in exercise and cachexia

Heat shock protein 60 (Hsp60) is a chaperon localizing in skeletal muscle mitochondria, whose role is poorly understood. This chaperone has been found also in other cellular localizations. In the three years we studied the levels of Hsp60 in fibres of the entire posterior group of hindlimb muscles (gastrocnemius, soleus, and plantaris) in mice after completing a 6-week endurance training program. In this evaluation we correlated Hsp60 levels with the expression of four isoforms of the peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α). Moreover, the short-term overexpression of hsp60, achieved by in vitro plasmid transfection was performed to determine whether this chaperon could have a role in the activation of the expression levels of PGC-1α isoforms. The levels of Hsp60 protein were fibre-type specific in the posterior muscles and endurance training increased its content in type I muscle fibers. Concomitantly with the increased levels of Hsp60 released in the blood stream of trained mice, mitochondrial copy number and the expression of three isoforms of PGC-1α increased. Overexpressing hsp60 in cultured myoblasts induced only the expression of PGC-1 α1, suggesting a correlation between Hsp60 overexpression and PGC-1 α1 activation. We are now studying the expression of Hsp60 in the muscles of trained and untrained C26-bearing mice, to understand if Hsp60 over expression may improve muscle performance and reduce cachexia. Four different interleukins have been also studied in cachectic mice, to understand which can be the effect of them on Hsp60 expression both in the tumor mass and the trained muscle.This work was funded by PRIN2009 - Prof. G. Zummo and PRIN2012 - Prof. Farina F