A large age for the pulsar B1757-24 from an upper limit on its proper motion

The "characteristic age" of a pulsar usually is considered to approximate its true age, but this assumption has led to some puzzling results, including the fact that many pulsars with small characteristic ages have no associated supernova remnants. The pulsar B1757-24 is located just beyond the edge of a supernova remnant; the properties of the system indicate that the pulsar was born at the centre of the remnant, but that it has subsequently overtaken the expanding blast-wave. With a characteristic age of 16,000 yr, this implies an expected proper motion by the pulsar of 63-80 milliarcsec per year. Here we report observations of the nebula surrounding the pulsar which limit its proper motion to less than 25 mas/yr, implying a minimum age of 39,000 yr. A more detailed analysis argues for a true age as great as 170,000 yr, significantly larger than the characteristic age. From this result and other discrepancies associated with pulsars, we conclude that characteristic ages seriously underestimate the true ages of pulsars

Exploring earned value management in the Spanish construction industry as a pathway to competitive advantage

[EN] As a well established discipline and profession, project management has its distinctive tools and techniques. One of them that has been considered the embodiment of the core principles of project management is the Earned Value Management (EVM). In managing construction projects, the EVM has been considered as a suitable tool and hence, has been implemented in various construction industry but absent in some others. Taking into account the dynamic environment where construction companies have to operate, particularly in turbulence environments as the direct result of recent global economic downturn, this paper explores the potential implementation of EVM in one of the construction industry, the Spanish construction industry. The outcomes confirm the needs for and feasibility of implementing EVM as a structured approach in the industry to reposition the Spanish construction industry with the long term view to increase its project management maturity level as a pathway to gaining competitive advantage.Universitat Politecnica de Valencia [grant number 19701344]Sutrisna, M.; Pellicer, E.; Torres-Machí, C.; Picornell, M. (2018). Exploring earned value management in the Spanish construction industry as a pathway to competitive advantage. International Journal of Construction Management. 20(1):1-12. https://doi.org/10.1080/15623599.2018.1459155S112201Anbari, F. T. (2004). Earned value project management method and extensions. IEEE Engineering Management Review, 32(3), 97-97. doi:10.1109/emr.2004.25113Aram, J. D., & Walochik, K. (1996). Improvisation and the Spanish Manager. International Studies of Management & Organization, 26(4), 73-89. doi:10.1080/00208825.1996.11656695Brandon, D. M. (1998). 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Adaptive Thermogenesis Driving Catch-Up Fat Is Associated With Increased Muscle Type 3 and Decreased Hepatic Type 1 Iodothyronine Deiodinase Activities: A Functional and Proteomic Study

Refeeding after caloric restriction induces weight regain and a disproportionate recovering of fat mass rather than lean mass (catch-up fat) that, in humans, associates with higher risks to develop chronic dysmetabolism. Studies in a well-established rat model of semistarvation-refeeding have reported that catch-up fat associates with hyperinsulinemia, glucose redistribution from skeletal muscle to white adipose tissue and suppressed adaptive thermogenesis sustaining a high efficiency for fat deposition. The skeletal muscle of catch-up fat animals exhibits reduced insulin-stimulated glucose utilization, mitochondrial dysfunction, delayed in vivo contraction-relaxation kinetics, increased proportion of slow fibers and altered local thyroid hormone metabolism, with suggestions of a role for iodothyronine deiodinases. To obtain novel insights into the skeletal muscle response during catch-up fat in this rat model, the functional proteomes of tibialis anterior and soleus muscles, harvested after 2 weeks of caloric restriction and 1 week of refeeding, were studied. Furthermore, to assess the implication of thyroid hormone metabolism in catch-up fat, circulatory thyroid hormones as well as liver type 1 (D1) and liver and skeletal muscle type 3 (D3) iodothyronine deiodinase activities were evaluated. The proteomic profiling of both skeletal muscles indicated catch-up fat-induced alterations, reflecting metabolic and contractile adjustments in soleus muscle and changes in glucose utilization and oxidative stress in tibialis anterior muscle. In response to caloric restriction, D3 activity increased in both liver and skeletal muscle, and persisted only in skeletal muscle upon refeeding. In parallel, liver D1 activity decreased during caloric restriction, and persisted during catch-up fat at a time-point when circulating levels of T4, T3 and rT3 were all restored to those of controls. Thus, during catch-up fat, a local hypothyroidism may occur in liver and skeletal muscle despite systemic euthyroidism. The resulting reduced tissue thyroid hormone bioavailability, likely D1- and D3-dependent in liver and skeletal muscle, respectively, may be part of the adaptive thermogenesis sustaining catch-up fat. These results open new perspectives in understanding the metabolic processes associated with the high efficiency of body fat recovery after caloric restriction, revealing new implications for iodothyronine deiodinases as putative biological brakes contributing in suppressed thermogenesis driving catch-up fat during weight regain