Labour market for teachers: Demographic characteristics and allocative mechanisms

The paper considers the teachers’ labour market in Italy. The quality and motivation of teachers are certainly among the determinants of pupils’ achievement, but they are difficult to measure, so we examine the composition of the pool of teachers and their behaviour to infer information about them. We look also at the institutional features that motivate the implicit contract that drives Italian teachers' behaviour, which essentially involves low salary and correspondingly low commitment and effort. In particular we examine the mechanism that allocates teachers to schools. For each school we construct three indicators; one indicating the level of turnover, which we interpret as a source of turmoil; one that refers to the mismatch between tenured teachers and their school; and a “revealed preferences indicator” that measures the schools’ quality as evaluated by the population of tenured teachers. We measure the association at the school level of our indicators with achievement as gauged by PISA 2003. Students scores are correlated negatively to the turnover and the mismatch indicators, positively to revealed preferences.Teachers labour market, Italian educational system

Reactive Oxygen Species in Skeletal Muscle Signaling

Generation of reactive oxygen species (ROS) is a ubiquitous phenomenon in eukaryotic cells' life. Up to the 1990s of the past century, ROS have been solely considered as toxic species resulting in oxidative stress, pathogenesis and aging. However, there is now clear evidence that ROS are not merely toxic species but also—within certain concentrations—useful signaling molecules regulating physiological processes. During intense skeletal muscle contractile activity myotubes' mitochondria generate high ROS flows: this renders skeletal muscle a tissue where ROS hold a particular relevance. According to their hormetic nature, in muscles ROS may trigger different signaling pathways leading to diverging responses, from adaptation to cell death. Whether a “positive” or “negative” response will prevail depends on many variables such as, among others, the site of ROS production, the persistence of ROS flow or target cells' antioxidant status. In this light, a specific threshold of physiological ROS concentrations above which ROS exert negative, toxic effects is hard to determine, and the concept of “physiologically compatible” levels of ROS would better fit with such a dynamic scenario. In this review these concepts will be discussed along with the most relevant signaling pathways triggered and/or affected by ROS in skeletal muscle

Spectral purity transfer with 5 × 10−17 instability at 1 s using a multibranch Er:fiber frequency comb

In this work we describe the spectral purity transfer between a 1156 nm ultrastable laser and a 1542 nm diode laser by means of an Er:fiber multibranch comb. By using both the master laser light at 1156 nm and its second-harmonic at 578 nm, together with the 1542 nm slave laser, we investigate the residual noise between the main comb output, the octave-spanning output, and a wavelength conversion module including non-linear fibers, second-harmonic generation crystal and amplifiers. With an ultimate stability of the system at the level of 5E−17 at 1 s and accuracy of 3E−19, this configuration can sustain spectral transfer at the level required by the contemporary optical clocks with a simple and robust setup

Absolute frequency measurement of the 1S0 – 3P0 transition of 171-Yb with a link to International Atomic Time

Dataset of the INRIM Yb clock measured respect to TAI collected between October 2018 to February 2019. YbvsSIm-viaEAL.dat: montly data with columns MJDstart: start date in MJD MJDstop: stop date in MJD MJDmed: mid point date in MJD MJDbaro: baricenter date in MJD Ybduty: Yb clock duty time y0=Yb/HM3: ratio between Yb clock and H Maser 03 u0: statistical uncertainty of y0 uB0: systematic uncertainty of y0 y1=extrap.: extrapolation over HM3 udead1: uncertainty of y1 from dead times udrift1: uncertainty of y1 from HM3 drift HM3drift/d: HM3 drift per day udrift/d: uncertainty of HM3 drift y2=HM3/UTCit: ratio between HM3 and UTC(IT) u2: uncertainty of y2 y3=UTCit/TAI: ratio between UTC(IT) and TAI u3: uncertainty of y3 y4=EALext.: extrapolation over EAL udead4: uncertainty of y4 from dead times udrift4: uncertainty of y4 from EAL drift y5=-d: ratio between TAI and the SI second from Circular T u5: uncertainty of y5 uA5: statistical uncertainty of y5 uB5: systematic uncertainty of y5 y=Yb/SI: final ratio beween the Yb clock and the Si second uA: not used uB: not used u: uncertainty of y YbvsTAId.dat: data every 5 days with columns: MJDstart: start date in MJD MJDstop: stop date in MJD MJDmed: mid point date in MJD MJDbaro: baricenter date in MJD Ybduty: Yb clock duty time y0=Yb/HM3: ratio between Yb clock and H Maser 03 u0: statistical uncertainty of y0 uB0: systematic uncertainty of y0 y1=extrap.: extrapolation over HM3 udead1: uncertainty of y1 from dead times udrift1: uncertainty of y1 from HM3 drift HM3drift/d: HM3 drift per day udrift/d: uncertainty of HM3 drift y2=HM3/UTCit: ratio between HM3 and UTC(IT) u2: uncertainty of y2 y3=UTCit/TAI: ratio between UTC(IT) and TAI u3: uncertainty of y3 y=Yb/TAI: final ratio beween the Yb clock and TAI uA: not used uB: not used u: uncertainty of yWe acknowledge funding from the European Metrology Program for Innovation and Research (EMPIR) project 15SIB03 OC18, from the Horizon 2020 Marie Skłodowska-Curie Research and Innovation Staff Exchange (MSCA-RISE) project Q-SENSE (Grant Agreement Number 691156), from the Italian Space Agency (ASI) funding DTF-Matera, from the EMPIR project 18SIB05 ROCIT. The EMPIR initiative is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR Participating States

Acute anterior myocardial infarction: Streptokinase prevents ventricular thrombosis independently of its effect on infarct size

Left ventricular thrombosis (LVT) is a frequent complication after acute anterior myocardial infarction (AMI). The purpose of this study is to evaluate whether streptokinase (SK) therapy prevents LVT, and whether this effect is due to the preservation of left ventricular function or to the fibrinolytic action of the drug. Sixty-five patients who underwent a left ventricular angiography within 2 months after a first AMI were studied. Twenty-eight patients (SK group) received SK 1,500,000 U i.v. administered over 60 min within 6 h from the onset of symptoms. A lower incidence of LVT was found in the SK group (p = 0.0003). We divided patients into two classes according to the value of akinetic-dyskinetic area (AD): the first group with a lower value of AD, the second group with a higher value of AD. In both groups, a reduced incidence of LVT was associated with SK therapy (p = 0.014, p = 0.015, respectively). Early infusion of SK during AMI seems to prevent the development of LVT, with an effect partly independent from its action on infarct size for small to large myocardial infarction

DESIGN OF A PROTOTYPE UNMANNED LIGHTER-THAN-AIR PLATFORM FOR REMOTE SENSING: STRUCTURAL DESIGN AND OPTIMIZATION

This work presents the structural design of a new Remotely Piloted Aircraft System (RPAS) concept for land survey applications. The RPAS Lighter-Than-Air (LTA) platform is equipped with a thrust vectoring control system made of six propellers attached to a single-rib exoskeletal load-bearing structure. The load-bearing structure is optimized to minimize structural mass, maximize payload capability, and meet the airship's operational requirements. A finite element model of the load-bearing structure was developed and analyzed under normal operating conditions of the airship, such as mid-air hovering and parking. Additionally, various failure cases, such as crash landing and control system failure, leading to haphazard operation of the propellers, were considered to simulate extreme load conditions on the airship exoskeletal structure. Airship slenderness was also considered an important design parameter and was optimized to maximize aerodynamic performance. A twin paper describes the other non-structural aspects of the airship design

Nutraceuticals and Physical Activity as Antidepressants: The Central Role of the Gut Microbiota

Major depressive disorder (MDD) is a common mental illness. Evidence suggests that the gut microbiota play an essential role in regulating brain functions and the pathogenesis of neuropsychiatric diseases, including MDD. There are numerous mechanisms through which the gut microbiota and brain can exchange information in a continuous, bidirectional communication. Current research emphasizes the interexchange of signals influenced by the gut microbiota that are detected and transduced in information from the gut to the nervous system involving neural, endocrine, and inflammatory mechanisms, suggesting a relationship between oxidative stress and the pathophysiology of MDD via the hyperactivation of inflammatory responses. Potential sources of inflammation in the plasma and hippocampus of depressed individuals could stem from increases in intestinal permeability. Some nutraceuticals, such as specific probiotics, namely psychobiotics, polyphenols, carotenoids, butyrate, and prebiotics, have been demonstrated to exert an antidepressant activity, but most of them need to be metabolized and activated by gut microorganisms. By inducing changes in the gut microbiota composition, physical exercise might also exert a role in alleviating depression-like symptoms. The mutual relationships among nutraceuticals, exercise, and depression will be discussed, and the potential role of the gut microbiota as a therapeutic target to treat depression will be explored

A complex species complex: The controversial role of ecology and biogeography in the evolutionary history of Syllis gracilis Grube, 1840 (Annelida, Syllidae)

The cryptic diversity in the polychaete Syllis gracilis Grube, 1840, in the Mediterranean Sea was examined with an integrative morpho-molecular approach. Individuals of S. gracilis were collected at eleven Mediterranean localities to provide an insight into the role of brackish environments in inducing cryptic speciation. The examination of morphological features combined with a molecular genetic analysis based on a partial sequence of the 16S rRNA gene highlighted discrepancies between morphological and molecular diversity. Morphological data allowed to identify a morphotype with short appendages occurring in coralline algae communities and another one with long appendages observed in brackish-water environments and Sabellaria reefs. Multivariate analyses showed that sampling localities were the greatest source of morphological divergence, suggesting that phenotypic plasticity may play a role in local adaptations of S. gracilis populations. Molecular data showed the occurrence of four divergent lineages not corresponding to morphological clusters. Different species delimitation tests gave conflicting results, retrieving, however, at least four separated entities. Some lineages occurred in sympatry and were equally distributed in marine and brackish-water environments, excluding a biogeographic or ecological explanation of the observed pattern and suggesting instead ancient separation between lineages and secondary contact. The co-occurrence of different lineages hindered the identification of the lineage corresponding to S. gracilis sensu stricto. The discrepancy between morphological and molecular diversity suggests that different environmental and biogeographic features may interact in a complex and unpredictable way in shaping diversity patterns. An integrative approach is needed to provide a satisfactory insight on evolutionary processes in marine invertebrates

Effects of a commercially available branched-chain amino acid-alanine-carbohydrate-based sports supplement on perceived exertion and performance in high intensity endurance cycling tests

Background:Sports nutritional supplements containing branched-chain amino acids (BCAA) have been widelyreported to improve psychological and biological aspects connected to central fatigue and performance inendurance exercise, although the topic is still open to debate. The aim of the present study was to determinewhether the intake of a commercially available BCAA-based supplement, taken according to the manufacturer’srecommendations, could affect the rating of perceived exertion (RPE) and performance indexes at the beginning(1d) and end of a 9-week (9w) scheduled high intensity interval training program, with an experimental approachintegrating the determination of psychometric, performance, metabolic and blood biochemical parameters.Methods:This was a randomized double-blind placebo-controlled study. Thirty-two untrained, healthy young adults(20 males and 12 female) were enrolled. A high-intensity endurance cycling (HIEC) test was used to induce fatigue inthe participants: HIEC consisted in ten 90 s sprints interspersed by ten 3 min recovery phases and followed by a finalstep time to exhaustion was used. In parallel with RPE, haematological values (creatine kinase, alanine, BCAA,tryptophan, ammonia and glucose levels), and performance indexes (maximal oxygen consumption - VO2max,powerassociated with lactate thresholds - WLT1,WLT2and time to exhaustion - TTE) were assessed. All subject took thesupplement (13.2 g of carbohydrates; 3.2 g of BCAA and 1.6 g of L-alanine per dose) or placebo before each test andtraining session. Dietary habits and training load were monitored during the entire training period.Results:The administration of the supplement (SU) at 1d reduced RPE by 9% during the recovery phase, as comparedto the placebo (PL); at 9w the RPE scores were reduced by 13 and 21% during the sprint and recovery phase,respectively; at 9w, prolonged supplement intake also improved TTE and TRIMP. SU intake invariably promoted a rapidincrease (within 1 h) of BCAA serum blood levels and prevented the post-HIEC tryptophan: BCAA ratio increase foundin the PL group, at both 1d and 9w. There was no difference in dietary habits between groups and those habits didnot change over time; no difference in glycemia was found between SU and PL. VO2max,WLT1and WLT2valuesimproved over time, but were unaffected by supplement intake. Conclusions:On the whole, these results suggest that i) the intake of the BCAA-based commercially availablesupplement used in this study reduces RPE as a likely consequence of an improvement in the serum tryptophan: BCAAratio; ii) over time, reduced RPE allows subjects to sustain higher workloads, leading to increased TRIMP and TTE