Identification of positrons and electrons in the cosmic radiation with the electromagnetic calorimeter ECAL for the AMS-02 experiment

In May 2011 AMS-02 detector has been successfully installed on the International Space Station (ISS), where it will take data on cosmic radiation from 1 to 1000 GeV for at least 10 years. Among all scientific objectives of the experiment, one of the most important is the search for Dark Matter (DM), which constitutes ∼ 80% of the Universe mass, but its nature is still unknown. A DM signal can be identified by studying the combined fluxes of positrons, photons, antiprotons and antideuterium. Thanks to its high acceptance and its performances, AMS-02 detector can extend and expand primary cosmic ray physics search to a new energy range with high accuracy. A key role for these measurements, in particular for electromagnetic channels, is played by ECAL calorimeter. This subdetector has been developed to measure γ, e− and e+ energy with an accuracy of few %. Thanks to its 3D shower reconstruction imaging capabilities, it also has a high separation power between electromagnetic and hadronic showers (e/p rejection), essential to eliminate proton background (∼ 10^4 ) in positron channel. Finally, it provides the trigger on photons which do not interact in the upper part of the detector (about 72% of the ones in ECAL geometrical acceptance). In Chapter 1 of this thesis, cosmic ray physics is introduced with details on Big Bang cosmology and the DM problem. Then, a summary of direct and in particular indirect searches for DM signature is presented. In Chapter 2 and 3 AMS-02 detector is presented with an overview of each subdetector features and performances. ECAL electromagnetic calorimeter is described in detail. Chapter 4 describes an in-flight calibration method, which has been developed and tested on August 2010 Test Beam data, with its application performances on ground and on in-flight data. In Chapter 5, the calorimeter capabilities have been used to develop e± identification algorithms, using both ECAL standalone and also tracker momentum measurements. The definition of algorithms, training and testing processes, data-MC comparisons and proton rejection spectrum are described

An epistemology of noise

Malaspina’s An Epistemology of Noise is a philosophical discussion of the concept of noise, illuminating both its preconditions and its far-reaching im- plications. In a literal sense, “noise” describes possible forms of human percep- tion related to aesthetics, acoustics, and audiometry. Figuratively, noise con- notes a range of negative qualities associated with disturbance, disruption, or perturbation. After we recognize that noise, especially in its aesthetic or com- monsense usage, is defined relationally, and occupies the negative position in a dichotomy with sound, we might ask: is there anything more to know to about noise? An Epistemology of Noise proves that there is. Considering noise an epis- temological problem as Malaspina does, its structural relevance for the theory of knowledge becomes clear. Indeed, Malaspina shows that noise allows us to address the epistemological question “how does knowledge constitute itself in the face of contingency”? and its flip-side “what role does uncertainty play in the constitution of knowledge”? (39) In this respect, the potential of the notion of noise has been largely neglected and is therefore still unexplored

Progettazione ed esecuzione di prova di collaudo su compressore centrifugo

Questo lavoro affronta il tema della progettazione e della realizzazione di un test meccanico ed un test termodinamico in condizioni di similitudine su un particolare compressore centrifugo, eseguito in accordo alle normative internazionali di settore (ASME PTC 10 e API 617). Lo scopo è quello di valutare le prestazioni del compressore in oggetto, quindi verificare la loro conformità alle suddette norme di riferimento e ai dati concordati in sede di contrattazione con il cliente. Inoltre è affrontata l’analisi di un fenomeno manifestatosi durante alcune prove termodinamiche di diversi compressori, che può avere un’influenza negativa sulla qualità dei risultati acquisiti; si tratta dell’oscillazione della portata del gas di processo in un punto stabile di lavoro. Tramite l’elaborazione di dati sperimentali acquisiti nel corso degli ultimi anni, si è individuata la causa di tale fenomeno nel dimensionamento della tubazione di aspirazione. A tal proposito è stata studiata un’ottimizzazione della progettazione del circuito di prova, ovviamente nel fedele rispetto delle normative di riferimento

Georges Canguilhem on sex determination and the normativity of life

Our goal in this paper is to reassess the relationship between norms and life by drawing on the philosophy of Georges Canguilhem, particularly some of his unpublished lectures about teratology and sexual determination. First, we discuss the difficulties Canguilhem identified in the introduction of life and sexuality as objects of philosophical reflection. Second, we reassess Canguilhem’s understanding of normativity as rooted in life and the axiological activity of the living. Third, we analyze how Canguilhem drew from past and contemporary teratology to conceive of the notions of anomaly and abnormality. Finally, we reconstruct Canguilhem’s analysis of a case of hermaphroditism, highlighting how he presented it as evidence that sexual determination is the result of a normative choice. One of the key contributions of the paper to scholarly literature on Canguilhem is a better understanding of his notion of choice, which was considered not the conscious and intentional act of a subject but rather an axiological activity of the living. We conclude by positioning Canguilhem’s concept of normativity and his belief that norms are produced by the living in relation to the naturalist/normativist divide in medicine

Results from AMS-02 on the ISS after 6 years in space

AMS-02 is a cosmic-ray detector which has been operating on the International Space Station since May 2011 to conduct a unique mission of fundamental research in space. More than 100 billion cosmic rays have been collected by AMS-02 after 6 years of operations, providing a detailed insight into the features of different species of cosmic rays. This contribution reviews the recent AMS-02 results based on 6 years of operations in space and their contribution to the advances in the understanding of cosmic-ray origin, acceleration and propagation physics

Measurement of the cosmic (e+ + e-) flux from 0.5 GeV to 1 TeV with the Alpha Magnetic Spectrometer (AMS-02) on the International Space Station

The measurement of cosmic ray positrons and electrons (e+/-) provides fundamental information about the origin of cosmic rays, and may disclose evidence for Dark Matter activity in the Galaxy. In this thesis, the 10.6 million e+/- events collected by the AMS-02 detector on the International Space Station in the first 30 months of data taking have been used to measure the (e+ + e-) flux from 0.5 GeV to 1 TeV with unprecedented precision. No structures have been observed in the resulting flux

Measurement of the cosmic ray (e + +e ) flux with AMS

The cosmic ray (e + + e ) flux has been measured by the Alpha Magnetic Spectrometer (AMS-02) in the energy range 0.5 GeV to 1 TeV, based on the analysis of 10.6 million e events collected during the first 30 months of data taking. The statistics and the resolution of the AMS-02 detector provide an accurate measurement in the whole energy range. No features have been observed in the flux, and the (e + + e ) spectrum can be accurately described by a single power law above 30 GeV. The procedures and the data analysis techniques for the (e + + e ) flux measurement are reviewed in this report

Sintesi di nuovi glicoconiugati inibitori del metabolismo glucidico

L’enzima LDH ricopre un ruolo chiave nelle patologie tumorali più invasive dove la condizione di ipossia determina un cambiamento metabolico della cellula che predilige la via glicolitica sfruttando la fermentazione lattica. Tra tutte le isoforme, l’enzima hLDH-5 possiede la maggior velocità di conversione del piruvato in lattato in condizioni di ipossia grazie alla presenza di quattro subunità di tipo M sovraespresse nelle cellule tumorali ipossiche. Tale enzima può essere dunque un valido target per il trattamento di alcuni tipi di tumore poiché la sua inibizione porta al mancato rifornimento di energia necessario per la sopravvivenza della cellula. In questo ambito, strutture contenenti il nucleo N-idrossiindolico si sono rivelate fra i più recenti ed interessanti inibitori dell’enzima LDH, in grado di fornire una buona inibizione enzimatica ed ottima attività antiproliferativa, soprattutto in condizioni di ipossia. Inoltre la sintesi di semplici glicoconiugati, contenenti come aglicone il nucleo N-idrossiindolico, ha fornito il primo esempio di doppio bersagliamento dell’effetto Warburg andando contemporaneamente ad esaltare, mediante l’impiego del trasportatore GLUT-1, il processo di uptake cellulare nelle cellule cancerose e ad interferire con il processo di glicolisi anaerobica che caratterizza le forme tumorali più invasive. L’obiettivo del presente lavoro di tesi è stato quello di sintetizzare nuovi glicoconiugati in considerazione del fatto che il trasportatore GLUT-1 non è specifico per il glucosio e che derivati N-idrossiindolici coniugati con altri tipi di saccaridi (mono- e disaccaridi) potessero presentare un miglior comportamento metabolico ed una migliore attività. In particolare la ricerca è stata volta alla: 1)sintesi di glicoconiugati anomerici attraverso reazioni di glicosilazione tra efficaci e classici glicosil donatori quali i tricloroacetimmidati del galattosio e del lattosio ed il nucleo N-idrossiindolico quale glicosil accettore ad elevata attività antitumorale; 2)sintesi di glicoconiugati portanti il nucleo attivo N-idrossiindolico in posizione C-6 al fine di valutare i rapporti struttura-attività di tali potenziali inibitori. I nuovi target sintetizzati sono stati infine sottoposti a saggi enzimatici e cellulari al fine di valutarne l’attività inibitoria

Neurological Assessment of Infants with Cerebral Arterial Ischaemic Stroke

ABSTRACT Arterial Ischaemic Stroke (AIS) occurs in approximately 0.25% of full term infants and around 1% of preterm infants. Up to 60% of perinatal strokes results in neurological deficits, with hemiplegic cerebral palsy (HCP) being a frequent adverse motor outcome. This is a lifelong condition that affects the daily living and the quality of life of these children and their families and often it is diagnosed only after the first year of life or even later, when significant asymmetries in upper extremity function and motor skill development are obvious. This is in contrast to adults who have a stroke who are identified with hemiparesis days not years after the brain injury. Motor outcomes in neonates with stroke are largely dependent on the location of the injury. The most common presenting feature of neonatal term infants with AIS is seizure and other common presentations include encephalopathy, apnea, tone abnormalities as well as persistent respiratory and feeding difficulties. Physical disability can range from minimal (e.g. weakness in one hand without discernible effects on activities of daily living) to profound (e.g. permanently restricted to a wheelchair and unable to eat or speak independently requiring 24h care). Today’s neuroimaging techniques such as ultrasound, computed tomography and magnetic resonance imaging, provide the possibility to identify brain lesions that may cause hemiplegia. Together with the classical neurological examination, these tools give us the possibility to perform prospective studies of the neurological development of these infants. What is still missing is a method that could help us for an early diagnosis of future neurological disabilities. There is actually no proof that early intervention could prevent the development of cerebral palsy in these infants, but it could help prevent secondary defects such as contractures and other forms of immobility, improving their future life. Many studies have confirmed that Prechtl’s Method of Qualitative Assessment of General Movements of infants is one of the most powerful predictive tools that we have. The General Movements Assessment (GMA) is a non-intrusive, reliable, quick and cost-effective method of functional assessment of the young nervous system developed by Heinz Prechtl and his colleagues of the Department of Developmental Neurology in Groningen (The Netherlands). This assessment is based on the observation of video-recordings showing the child during his spontaneous motility, with nobody neither touching nor stimulating him. By observation we could be able to distinguish between normal and abnormal general movements. Normal General Movements are gross movements involving the whole body; they may last from a few second to several minutes or longer. What is particular about them is the variable sequence of arm, leg, neck and trunk movements. They wax and wane in intensity, force and speed and they also have a gradual beginning and end. The majority of sequences of extension and flection movements of arms and legs is complex, with superimposed rotations and frequent slight changes in the direction of the movement. These additional components make the movement fluent and elegant and create the impression of complexity and variability. Abnormal General Movements are movements lacking complexity, variability and fluency. They could be poor in their quality, or cramped synchronised or even chaotic. These features can be related to some neurological deficits, which can range from cerebral palsy to mild neurological disabilities. Previous studies highlighted the important predictive power of Fidgety movements, which emerge around 6-9 weeks of post-term age. Fidgety movements are small movements of moderate speed and variable acceleration of neck, trunk and limbs, in all directions, continual in the awake infant, except during focused attention, fussing and crying. They may be seen as early as 6 weeks but usually occur around 9 weeks and are present until 20 weeks or even a few weeks longer, at which time intentional, goal directed, and antigravity movements occur and start to dominate. The absence of fidgety movements is highly predictive for later neurological impairments, particularly for cerebral palsy, both the spastic and dyskinetic forms. General movements can be observed also in fetuses as young as nine weeks postmenstrual age (age of the fetus or infant calculated from the date of the mother’s last period), that is why this method can be of a real support for an early diagnosis. In our study we tried to use this method on a population of 22 full-term infants, 6 were healthy infants, while 16 have been diagnosed with perinatal arterial ischaemic stroke. The aim of this study was to confirm the predictive value of the qualitative assessment of spontaneous motor activity, together with the evaluation of the Motor Repertoire and the assessment of asymmetries in various body parts. We wanted to analyse to what extent the long-term neurological outcome of infants diagnosed with neonatal stroke is related to their motor performance at age 3 to 5 months; to confirm the predictive power of the quality of fidgety movements and the significant correlation between asymmetry of segmental movements and the presence of later hemiplegia in infants with neonatal stroke; to find a correlation between severe neurological outcome and asymmetry in hand movements, kicking, trunk bending and foot-foot contact and to confirm or reject the theory of the silent period that would prevent an early diagnosis of unilateral CP