Radiative corrections of heavy scalar decays to gauge bosons in the singlet extension of the Standard Model

Assuming the existence of a new real scalar singlet $s^0$ coupled to the Standard Model via a scalar quartic portal interaction, we compute the radiative corrections to the decay rates of the heavy scalar mass eigenstate to a couple of gauge bosons $ZZ$ and $W^+W^-(\gamma)$, showing that they can give a contribution as large as ${\cal{O}}$(5\%) and ${\cal{O}}$(7\%), respectively. We also explicitly analyze in detail their dependence on the heavy mass $m_S$ and on the scalar mixing angle $\alpha$, finding that, especially in the large-mass region, these depend on the sign of $\sin\alpha$.Comment: 23 pages, 7 figure

La (Escéptica) Excepción. Platón y el caso de la religión (a través de la poesía)

El propósito de este artículo es doble. Por un lado, trata de responder a la pregunta de por qué Platón es el único filósofo de la antigüedad que promueve que la comunidad al completo debe sostener las mismas creencias sobre lo divino. Tal postura, como sostengo en el presente artículo, se asienta entre el escepticismo y el secularismo. Por otro, este trabajo trata de mostrar que no hay justificación alguna para atribuir a Platón dudas escépticas al valor artístico de la poesía. De hecho, tal y como defiendo mediante un análisis textual detallado, la actitud de Platón hacia las creencias religiosas coincide plenamente con los argumentos de Platón contra la poesía en la República libros II y III.The aim of this paper is twofold. First, it answers the question of why Plato is the only philosopher in antiquity that urges that the entire community must hold the same, right beliefs about the divine. Such a position, as I argue in the present work, stands between skepticism and secularism. Second, the present work shows that there is no justification for attributing skeptical doubts on artistic value in poetry to Plato. Indeed, as I emphasize by means of a detailed textual analysis, Plato’s attitude toward religious beliefs concurs with Plato’s arguments against poetry in Republic II and III

Chemistry and biology of mammalian metallothioneins

Metallothioneins (MTs) are a class of ubiquitously occurring low molecular mass, cysteine- and metal-rich proteins containing sulfur-based metal clusters formed with Zn(II), Cd(II), and Cu(I) ions. In mammals, four distinct MT isoforms designated MT-1 through MT-4 exist. The first discovered MT-1/MT-2 are widely expressed isoforms, whose biosynthesis is inducible by a wide range of stimuli, including metals, drugs, and inflammatory mediators. In contrast, MT-3 and MT-4 are noninducible proteins, with their expression primarily confined to the central nervous system and certain squamous epithelia, respectively. MT-1 through MT-3 have been reported to be secreted, suggesting that they may play different biological roles in the intracellular and extracellular space. Recent reports established that these isoforms play an important protective role in brain injury and metal-linked neurodegenerative diseases. In the postgenomic era, it is becoming increasingly clear that MTs fulfill multiple functions, including the involvement in zinc and copper homeostasis, protection against heavy metal toxicity, and oxidative damage. All mammalian MTs are monomeric proteins, containing two metal-thiolate clusters. In this review, after a brief summary of the historical milestones of the MT-1/MT-2 research, the recent advances in the structure, chemistry, and biological function of MT-3 and MT-4 are discusse

Control of Abnormal Metal-Protein Interactions in Neurodegenerative Disorders by Metallothionein-3

In the brain, zinc and copper homeostasis is regulated by a small metalloprotein, metallothionein-3 (Zn7MT-3), which is down-regulated in neurodegenerative diseases such as Alzheimer (AD), Creutzfeldt-Jacob and Parkinson. These disorders share common pathological hallmarks including misfolding of amyloid-? (A?), prion protein and ?-synuclein, the formation of protein aggregates, abnormal metal-protein interactions and oxidative stress. In AD, Cu(II) and Zn(II) areinvolved in the disease progression by modulating the formation and toxicity of soluble and insoluble oligomers and aggregates of the A? peptide. Whereas the copper-induced A? aggregation is related to the ROS production and neurotoxicity, the zinc-induced A? aggregation is considered neuroprotective. The protective effect of extracellular Zn7MT-3 from A? toxicity in neuronal cell cultures is not understood. We show that Zn7MT-3 not only scavenges freeCu(II) ions, but also removes Cu(II) bound to A?. A metal swap between Zn7MT-3 and soluble and aggregated A?-Cu(II) is the underlying molecular mechanism by which the ROS production and related cellular toxicity is abolished. In this process, copper is reduced by the protein thiolates forming Cu(I)4Zn4MT-3, in which an air stable Cu(I)4-thiolate cluster and two disulfide bonds are present. To examine whether the discovered effect represents ageneral protective role of this protein in other metal-linked neurodegenerative pathologies, similar studies using prion peptides in complex with Cu(II) were conducted. Zn7MT-3 by a similar metal swap reaction removes abnormally bound Cu(II) from the prion protein, impeding the ROS production. This finding signifies a so far unrecognized protective role of this protein in the brain

Plato on establishing poetry as art

Plato’s attitude on Art has always been hardly debated among scholars, and in recent times the interest on ancient Aesthetics in general and Plato’s attitude in particular has been even increased in the philosophical debate. The problem with Plato’s position is twofold. On the one hand he expresses hard criticism against poetry and he even banishes the poets from the ideal state he envisages in the Republic. That has been usually regarded as an illiberal, totalitarian position. On the other hand, the criticisms he makes of poetry seem to present inconsistencies among the Platonic corpus and they could prima facie appear to the modern reader odd, paternalistic or moralistic. Throughout my work I suggest to adopt a new approach, based both on historical and theoretical grounds, according to which it will be possible to resolve the problems that Plato’s objections to poetry give rise to. The historical and cultural context will be the focus of the first chapter. It consists of the following points. On the one hand I will first focus on different features that characterize Greek poetry, and on the other I will emphasize the pre-literacy of Plato’s contemporaries. I will also highlight how the ethical and political role, along with the educational function, made poetry the privileged source of information and education, and the ultimate reference for everyone in the Athens of the fifth B.C. In the second section of the first chapter I will analyze Plato’s teleologism, which I regard to be a fundamental entity in his stance on art. Such a notion, although not as much emphasized by scholars, plays a pivotal role in Plato’s arguments on poetry, I contend. This is especially evident in the Republic, where Plato’s criticism regards the flaws of poetry in teaching (Resp. II and III) first, and secondly as the main source of knowledge (X). In the third and last section of chapter one, I will face the complex issue of the alleged existence of the concept of beauty in antiquity. In this occasion I argue in favour of the existence of such an entity, both among average Greeks and for Plato, even though in different ways and degrees of awareness. After having provided the historical and theoretical frame of my approach, I will then move to textual examination of the Platonis Opera. In the second and third chapter I will analyse the so-called ‘early dialogues’, in order to single out the recurrent features of Plato’s stance on poetry. In fact, one of the main goals of my study is to retrace an overall, consistent view on art in general and poetry in particular among the Platonic corpus. While the second chapter is mainly focused on the Apology and the Protagoras, a special emphasis deserves the Ion, which is the object of the third chapter. I argue indeed that for the first time in this early dialogue we find a clear theoretical expression of a key-concept of Plato’s stance on art. In fact, Plato bases his criticism toward the eponymous rhapsode pointing out that the rhapsode on the one hand lacks the knowledge of the things he (demands to be able to) talk(s) about. On the other hand, the rhapsode lacks the knowledge of what poetry, as well as his trade, is. Such a ‘twofold ignorance’, as we will see, it is a recurring pattern in Socrates’ pupil. While the fourth chapter is mainly devoted to the analysis and comment of the Symposium, the fifth, sixth and seventh chapter present the detailed examination of the Book II, III and X of the Republic. They are respectively devoted to the analysis and criticism of the ‘middle dialogues’, the Republic and the ‘late dialogues’. Because of its capital importance for the purpose of my argument, I will analyze Plato’s criticism in the Republic in details and I will face different approaches to the subject. Afterwards I will confront them with my own theory in order to show that adopting my approach the apparent discrepancies regarding Plato’s aesthetics within the Republic itself as well as in others Platonic dialogues disappear. (And, on the contrary, this does not happen if the reader accepts the mainstream interpretation on the subject at issue). In essence: I propose to take Plato’s criticism of poetry not as an aesthetic attitude, but rather as a justified concern about the pursuit of truth through poetry, as if it were the main source of teaching, moral value, knowledge and information in the ancient Greek society. That is the core of my argument. The eighth chapter analyses the ‘late dialogues’, in particular The Laws, given the abundant of relevant passages on the matter. Finally, the ninth and last chapter faces Popper’s notorious judgement of Plato as totalitarian scholar. In this section of the study I will contend that Popper’s notorious reading of Plato’s political system is fallacious. Further, I will reveal that Plato and Popper’s stance on mass media essentially correspond. It is my understanding that such a fundamental passage will give the ultimate proof of the rightness of my revolutionary reading of the vexata quaestio of the ancient quarrel between philosophy and poetry in Plato. Finally, the outcome of my investigations will show that Plato does not banish poetry because he is attacking it as a dangerous, free, “fine” Art. On the contrary, I propose to take his attack as the only way to release poetry from its educational and political context and to baptize it into the realm of Fine Art

On the complexity of the boundary layer structure and aerosol vertical distribution in the coastal Mediterranean regions: A case study

The planetary boundary layer structure in the coastal areas, and particularly in complex orography regions such as the Mediterranean, is extremely intricate. In this study, we show the evolution of the planetary boundary layer based on in situ airborne measurements and ground-based remote sensing observations carried out during the MORE (Marine Ozone and Radiation Experiment) campaign in June 2010. The campaign was held in a rural coastal Mediterranean region in Southern Italy. The study focuses on the observations made on 17 June. Vertical profiles of meteorological parameters and aerosol size distribution were measured during two flights: in the morning and in the afternoon. Airborne observations were combined with ground-based LIDAR, SODAR, microwave and visible radiometer measurements, allowing a detailed description of the atmospheric vertical structure. The analysis was complemented with data from a regional atmospheric model run with horizontal resolutions of 12, 4 and 1 km, respectively; back-trajectories were calculated at these spatial resolutions. The observations show the simultaneous occurrence of dust transport, descent of mid-tropospheric air and sea breeze circulation on 17 June. Local pollution effects on the aerosol distribution, and a possible event of new particles formation were also observed. A large variability in the thermodynamical structure and aerosol distribution in the flight region, extending by approximately 30km along the coast, was found. Within this complex, environment-relevant differences in the back-trajectories calculated at different spatial resolutions are found, suggesting that the description of several dynamical processes, and in particular the sea breeze circulation, requires high-resolution meteorological analyses. The study also shows that the integration of different observational techniques is needed to describe these complex conditions; in particular, the availability of flights and their timing with respect to the occurring phenomena are crucial

Transmembrane Type-2-like Cu^(2+) Site in the P_(1B-3)-type ATPase CopB: Implications for Metal Selectivity

Metal selectivity in P_(1B)-type ATPase transporters is determined by conserved amino acid residues in their transmembrane helices responsible for metal binding and transport across the cellular membrane. The Cu^(2+)-selective CopB from Archaeoglobus fulgidus has been investigated to explore the coordination chemistry of the transition metal binding sites in P_(1B-3)-type ATPases. Electronic absorption, electron paramagnetic resonance, and X-ray absorption spectroscopic studies indicate the presence of a high-affinity transmembrane Type-2-like Cu^(2+) center in which a single cupric ion is coordinated in a distorted square pyramidal geometry by mixed nitrogen/oxygen and sulfur ligands

Response of the Cardiac Autonomic Control to Exposure to Nanoparticles and Noise: A Cross-Sectional Study of Airport Ground Staff

Airport activity causes the emission of particulate matter and noise, two environmental contaminants and potential health hazards, particularly for the personnel operating nearby taxiways. We explored the association between exposure to fine/ultrafine particles (UFPs) and noise with heart rate variability (HRV), an early indicator of cardiovascular autonomic response, among a sample of airport ground staff. Between May and June 2018, thirty-four male operators (mean age = 43 years and SD = 6.7) underwent personal monitoring of exposure to nanoparticles and noise, and HRV during their work activity. We conducted univariate and multivariate analysis to test the effect of UFP and noise exposure HRV. Total Lung Deposition Surface Area (LDSA) was significantly associated with a decrease in HRV Total Power and Triangular index (beta = -0.038 p = 0.016 and beta = -7.8 x 10(-5), p = 0.042, respectively). Noise peak level showed an opposite effect, which was significant for Total Power (beta = 153.03, p = 0.027), and for Triangular index (beta = 0.362, p = 0.035). Further investigation is warranted to clarify the effect of the concurrent exposure to UFPs and noise on early changes of cardiac autonomic regulation

A sulfur-based transport pathway in Cu^+-ATPases

Cells regulate copper levels tightly to balance the biogenesis and integrity of copper centers in vital enzymes against toxic levels of copper. P_(IB)‐type Cu^+‐ATPases play a central role in copper homeostasis by catalyzing the selective translocation of Cu^+ across cellular membranes. Crystal structures of a copper‐free Cu^+‐ATPase are available, but the mechanism of Cu^+ recognition, binding, and translocation remains elusive. Through X‐ray absorption spectroscopy, ATPase activity assays, and charge transfer measurements on solid‐supported membranes using wild‐type and mutant forms of the Legionella pneumophila Cu^+‐ATPase (LpCopA), we identify a sulfur‐lined metal transport pathway. Structural analysis indicates that Cu^+ is bound at a high‐affinity transmembrane‐binding site in a trigonal‐planar coordination with the Cys residues of the conserved CPC motif of transmembrane segment 4 (C382 and C384) and the conserved Met residue of transmembrane segment 6 (M717 of the MXXXS motif). These residues are also essential for transport. Additionally, the studies indicate essential roles of other conserved intramembranous polar residues in facilitating copper binding to the high‐affinity site and subsequent release through the exit pathway

The Sixteenth Iron in the Nitrogenase MoFe Protein

Another iron in the fire: X-ray anomalous diffraction studies on the nitrogenase MoFe protein show the presence of a mononuclear iron site, designated as Fe16, which was previously identified as either Ca^(2+) or Mg^(2+). The position of the absorption edge indicates that this site is in the oxidation state +2. The high sequence conservation of the residues coordinated to Fe16 emphasizes the potential importance of the site in nitrogenase