Different stellar rotation in the two main sequences of the young globular cluster NGC1818: first direct spectroscopic evidence

We present a spectroscopic analysis of main sequence (MS) stars in the young globular cluster NGC1818 (age~40 Myrs) in the Large Magellanic Cloud. Our photometric survey on Magellanic Clouds clusters has revealed that NGC1818, similarly to the other young objects with age 600 Myrs, displays not only an extended MS Turn-Off (eMSTO), as observed in intermediate-age clusters (age~1-2 Gyrs), but also a split MS. The most straightforward interpretation of the double MS is the presence of two stellar populations: a sequence of slowly-rotating stars lying on the blue-MS and a sequence of fast rotators, with rotation close to the breaking speed, defining a red-MS. We report the first direct spectroscopic measurements of projected rotational velocities vsini for the double MS, eMSTO and Be stars of a young cluster. The analysis of line profiles includes non-LTE effects, required for correctly deriving v sini values. Our results suggest that: (i) the mean rotation for blue- and red-MS stars is vsini=71\pm10 km/s (sigma=37 km/s) and vsini=202\pm23 km/s (sigma=91 km/s), respectively; (ii) eMSTO stars have different vsini, which are generally lower than those inferred for red-MS stars, and (iii) as expected, Be stars display the highest vsini values. This analyis supports the idea that distinct rotational velocities play an important role in the appearence of multiple stellar populations in the color-magnitude diagrams of young clusters, and poses new constraints to the current scenarios.Comment: 16 pages, 1 table, 9 figures. Accepted for publication in AJ (11/07/2018

Global city: the occupational layer

Nowadays discussion on global cities concept is being addressed on European level. The concept is a consequence of multiplicities of globalization processes adding different layers according to social, economic and environmental requirements. Cities must also be seen as working systems, with the same needs and requirements in terms of safety and well-being that are considered for other systems. In this paper Authors address the evidences that support the importance of this additional layer. Different sources were used in order to obtain the data related to working systems and their relation to the global cities concept. The conducted systematic review indicate that the search words: sustainability, occupational and global city were not crossed for research. Furthermore, challenges that cities are facing must be understood as additional source of motivation and innovation towards a global city. Cities must also be seen as working systems, with the same needs and requirements in terms of safety and well-being that are considered for other systems

Gitelman syndrome

Hypokalaemia is a common clinical disorder, the cause of which can usually be determined by the patient's clinical history. Gitelman syndrome is an inherited tubulopathy that must be considered in some settings of hypokalaemia. We present the case of a 60-year-old male patient referred to our nephrology department for persistent hypokalaemia. Clinical history was positive for symptoms of orthostatic hypotension and polyuria. There was no history of drugs consumption other than potassium supplements. Complementary evaluation revealed hypokalaemia (2.15 mmol/l), hypomagnesaemia (0.29 mmol/l), metabolic alkalosis (pH 7.535, bicarbonate 34.1 mmol/l), hypereninaemia (281.7 U/ml), increased chloride (160 mmol/l) and sodium (126 mmol/l) urinary excretion and reduced urinary calcium excretion (0.73 mmol/l). Renal function, remainder serum and urinary ionogram, and renal ultrasound were normal. A diagnosis of Gitelman syndrome was established. We reinforced oral supplementation with potassium chloride and magnesium sulfate. Serum potassium stabilised around 3 mmol/l. The aim of our article is to remind Gitelman syndrome in the differential diagnosis of persistent hypokalaemi

PD-L1/PD-1 axis in multiple myeloma microenvironment and a possible link with CD38-mediated immune-suppression

The emerging role of the PD-1/PD-L1 axis in MM immune-microenvironment has been highlighted by several studies. However, discordant data have been reported on PD-1/PD-L1 distribution within the bone marrow (BM) microenvironment of patients with monoclonal gammopathies. In addition, the efficacy of PD-1/PD-L1 blockade as a therapeutic strategy to reverse myeloma immune suppression and inhibit myeloma cell survival still remains unknown. Recent data suggest that, among the potential mechanisms behind the lack of responsiveness or resistance to anti-PD-L1/PD-1 antibodies, the CD38 metabolic pathways involving the immune-suppressive factor, adenosine, could play an important role. This review summarizes the available data on PD-1/PD-L1 expression in patients with MM, reporting the main mechanisms of regulation of PD-1/PD-L1 axis. The possible link between the CD38 and PD-1/PD-L1 pathways is also reported, highlighting the rationale for the potential use of a combined therapeutic approach with CD38 blocking agents and anti-PD-1/PD-L1 antibodies in order to improve their anti-tumoral effect in MM patients

Accelerating networks

Evolving out-of-equilibrium networks have been under intense scrutiny recently. In many real-world settings the number of links added per new node is not constant but depends on the time at which the node is introduced in the system. This simple idea gives rise to the concept of accelerating networks, for which we review an existing definition and -- after finding it somewhat constrictive -- offer a new definition. The new definition provided here views network acceleration as a time dependent property of a given system, as opposed to being a property of the specific algorithm applied to grow the network. The defnition also covers both unweighted and weighted networks. As time-stamped network data becomes increasingly available, the proposed measures may be easily carried out on empirical datasets. As a simple case study we apply the concepts to study the evolution of three different instances of Wikipedia, namely, those in English, German, and Japanese, and find that the networks undergo different acceleration regimes in their evolution.Comment: 12 pages, 8 figure

Prominent effect of soil network heterogeneity on microbial invasion

Using a network representation for real soil samples and mathematical models for microbial spread, we show that the structural heterogeneity of the soil habitat may have a very significant influence on the size of microbial invasions of the soil pore space. In particular, neglecting the soil structural heterogeneity may lead to a substantial underestimation of microbial invasion. Such effects are explained in terms of a crucial interplay between heterogeneity in microbial spread and heterogeneity in the topology of soil networks. The main influence of network topology on invasion is linked to the existence of long channels in soil networks that may act as bridges for transmission of microorganisms between distant parts of soil