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Predictive validity of intelligence tests on school performance
No full textI diversi studi che hanno indagato la relazione che c’è tra intelligenza e prestazioni scolastiche hanno condotto a risultati contrastanti. In letteratura scientifica troviamo poche revisioni che includono studi recenti sul tema. L’obiettivo di questa rassegna sistematica è quello di rispondere alla domanda: l’intelligenza predice le prestazioni scolastiche?
Per questa rassegna sistematica sono state consultate due banche dati: Pubmed e Scopus. La ricerca degli studi è aggiornata a settembre 2024. I criteri di eleggibilità scelti sono relativi alla: lingua: Inglese; data di pubblicazione: dal 2014 al 2024; misure variabile indipendente: test di intelligenza standardizzati; misure variabile dipendente: test standardizzati o media dei voti; popolazione: non clinica; tipologia di studio: studi quantitativi.
Nella rassegna sono stati inclusi undici studi finali. I risultati di questa rassegna sistematica suggeriscono che l’intelligenza ha una sostanziale influenza sulle prestazioni scolastiche. Il fattore g predice in maniera significativa le performance scolastiche ugualmente in entrambi i sessi. Inoltre, l’intelligenza, con l’avanzare degli anni di scuola, tende a spiegare sempre meno varianza delle prestazioni scolastiche.Studies investigating the relation between intelligence and school performance led us to conflicting results. In scientific literature, there are few reviews of recent studies on this topic. The aim of this systematic review is to answer the question: does intelligence predict school performance?
Two databases were consulted for this systematic review: Pubmed and Scopus. The study search is updated to September 2024. The eligibility criteria chosen are related to: language: English; pub lication date: 2014 to 2024; independent variable measures: standardized intelligence tests; dependent variable measures: standardized tests or grade point average; population: non-clinical; study type: quantitative studies.
Eleven studies are included in the systematic review. The results of this systematic review suggest that intelligence has a substantial influence on school performance. The g factor significantly predicts school performance equally in both sexes. Intelligence, as school years progress, tends to explain less and less variance in school performance
Observational study of adrenal neoplasia in dogs
No full textLe neoplasie surrenaliche sono un reperto comune nei cani anziani. In base al tasso di malignità e alla scelta terapeutica per ciascun cane, i tempi di sopravvivenza sono diversi. L’obiettivo dello studio era valutare la sopravvivenza nei cani trattati medicalmente o chirurgicamente. È stato condotto uno studio osservazionale longitudinale retrospettivamente e prospetticamente, raccogliendo i dati dall’Ospedale Veterinario di due istituzioni. La ricerca ha portato all’inclusione di 34 pazienti che rispondevano ai criteri di inclusione stabiliti. I dati raccolti riguardano le visite cliniche, la diagnostica per immagini, la chirurgia, la citologia, l’istologia, i test ormonali e i vari outcome. L’intervento chirurgico è stato eseguito in 22 cani (65%), tutti con diagnosi istologica di 14 carcinoma corticale, 5 adenoma corticale e 3 feocromocitoma. Questi cani presentano una diagnosi finale di Cushing (63%), feocromocitoma (13%) e tumore adrenale non funzionale (23%).
Il trattamento medico è stato eseguito in 12 cani (35%), tra questi, 5 sono stati sottoposti a citologia e la diagnosi finale è stata di Cushing (33%), tumore adrenale non funzionale (25%), feocromocitoma (16%) e diagnosi non definita (25%). I risultati mostrano un tempo di sopravvivenza dei cani trattati chirurgicamente di 1273 giorni; invece, quello dei cani trattati farmacologicamente è indefinito. Tuttavia, mediante una regressione di cox è stato possibile stabilire che non c’è differenza tra i tempi di sopravvivenza dei due gruppi. Inoltre, 11 cani hanno mostrato un valore di ACTH endogeno vicino al limite inferiore (5pg/mL) e riportavano una diagnosi finale di tumore surrenalico funzionale. La citologia e l’istologia erano entrambe disponibili nel 41% dei cani e nel 93% dei casi la citologia si è dimostrata accurata nel classificare l’origine del tumore. In conclusione, non c’è una differenza significativa nella sopravvivenza tra i cani trattati chirurgicamente o farmacologicamente, quindi la scelta del trattamento medico può essere un’ottima alternativa per i cani che non possono essere sottoposti a intervento chirurgico o che sono molto anziani.Adrenal neoplasia is a common finding in older dogs. Based on the rate of malignancy and on the treatment choice for each dog, there are different survival time. The objective of the study was to evaluate the survival in dogs treated medically or surgically. A longitudinal observational study was conducted both retrospectively and prospectively, collecting data from Veterinary Teaching Hospital of two institutions. Data regarding clinical findings, results of imaging diagnostic, cytology, histology, hormonal tests, and outcome were collected.
The search resulted in the inclusion of 34 patients, meeting the established inclusion criteria. Surgery was performed in 22 dogs (65%) and histology was performed in all of them, diagnosing 15 cortical carcinoma, 4 cortical adenoma, and 3 pheochromocytoma. These dogs presented a final diagnosis of Cushing’s syndrome (63%), pheochromocytoma (13%), and non-functional AT (23%). Medical treatment was performed in 12 dogs (35%) and the final diagnosis was Cushing’ s Syndrome (33%), non-functional AT (25%), pheochromocytoma (16%), and not defined diagnosis (25%). Also, 11 dogs presented a value of endogenous ACTH below the lower limit of detection of the assay (<5 pg/mL) and all had a final diagnosis of functional adrenal tumor. Cytology and histology were concomitantly available in 41% of dogs, and in 93% of them the cytology proved accurate in classifying the origin of the tumor.
Median survival time of dogs treated surgically was 1273 days; the survival time of dogs treated medically was not reached but most dogs showed prolonged survival before being censored. There was no difference between the survival of the two groups. In conclusion, despite these results must be interpreted with caution due the possibility of a type II error, the medical treatment may be a good alternative for dogs that cannot undergo surgery or for geriatric dogs
Molecular functional materials: molecules and aggregates towards the thermodynamic limit
No full textMolecular functional materials are in the spotlight of scientific research as the most promising path towards innovative applications in sustainable and recyclable optoelectronic devices, in bioimaging, sensing, photonics, teleommunications etc. The virtually infinite possibilities offered by organic synthesis allow for an extremely fine tuning of the molecular properties for improved performances. In this context, theoretical modeling is an essential tool to guide the synthesis, providing clear design strategies for optimized systems. Quantum chemical calculations, available to the scientific community in a large number of software packages, represent one of the most successful and widely exploited approaches to address molecular systems. However, the collective properties of a material are not simply the sum of molecular properties and therefore are often beyond the scope of standard computational tools.
Two issues in this respect must be faced. The first and most generally recognized issue falls under the broad definition of environmental effects. As aforementioned, the properties of a molecular system are determined
not just by the properties of the molecules themselves, as calculated, e.g., via gas phase ab initio calculations, but are crucially affected by intermolecular interactions. Wildly different environments define the most rich and diverse array of phenomena. The variability is substantial, ranging, for example, from liquid solution to a molecular dispersion in a solid matrix, from a completely disordered amorphous phase to ordered aggregates and crystals. Polar solvation dynamics, static and dynamical disorder, excitonic effects are just some examples of the many possible phenomena that determine the photophysics of the material and its properties like, e. g., charge transport and mobility and energy transfer.
A second, more subtle issue arises from the fact that materials are macroscopic systems, so that a reliable and complete description of their behavior and properties cannot be obtained focusing on the microscopic domain of molecular quantum mechanics, but requires entering the fascinating world of open quantum systems, as to effectively connect the microscopic quantum realm of a single (or a few) molecule and the macroscopic world. Energy dissipation is crucial to bridge the gap between quantum mechanics and thermodynamics. An explicit quantum mechanical treatment of a system large enough to ensure a realistic evolution of energy fluxes is clearly unfeasible. Open quantum system approaches offer an elegant strategy to overcame this limit. In few words, out of the macroscopic object a system is identified, corresponding to the portion of the object or to the subset of degrees of freedom of interest. This system interacts with the rest of the world, the bath, that acts as a
thermal reservoir.
In this thesis, both issues are faced with reference to a specific family of molecular systems, the so-called charge transfer (CT) dyes. CT dyes are a wide class of chromophores whose low energy physics is successfully
modeled by essential state models (ESMs), where few electronic states are coupled to few effective vibrational coordinates in a non-adiabatic picture. Specifically, environmental effects on the photophysics of CT dyes in different environments are addressed in the next chapters. The journey is divided in two main parts. In the first part the world of open quantum systems is entered to describe the relaxation of a single photoexcited chromophore in gas phase, in solution or in solid matrices. The second part is then dedicated to molecular aggregates and crystals.
In chapter 1, the well known and widely applied ESM for a polar (donor-acceptor) dye is extended to describe the relaxation dynamics following coherent photoexcitation. To this aim the Redfield approach to open quantum systems is adopted. Subtleties and technicalities of the coupling with the bath are carefully analyzed setting a solid basis for subsequent work. The approach is validated via simulations of time-resolved emission spectra.
In chapter 2 the model is extended to account for polar solvation. The polar environment is treated classically as an overdamped coordinate whose dynamics is governed by the Smoluchowski equation. The model is applied to investigate the static and dynamical dielectric properties of organic amorphous matrices commonly used as dispersion media for the emitters in organic light emitting diods (OLEDs). The simulation of time-resolved emission spectra of a solvatochromic polar dye (a microscopic polarity sensor) in solvents and solid amorphous matrices of different polarity validates the model and allows to extract for the first time significant information about the relaxation times of these materials, opening a novel perspective on solid state solvation.
Chapter 3 initiates the second part of the thesis, introducing the world of molecular aggregates and presenting the celebrated Frenkel-Holstein (FH) Hamiltonian for aggregates of molecules interacting via electrostatic forces. Special focus is put on the interplay between nearest neighbor and next-nearest neighbor interactions in defining the vibronic bandshapes in absorption spectra. The FH Hamiltonian is then used to simulate polarized absorbance spectra of crystalline thin films of SQIB, a squaraine dye suited for photovoltaic applications.
In chapter 4 molecular aggregates are addressed in the framework of essential state models, making a clear connection with the standard exciton model discussed in chapter 3. The Redfield relaxation model set up in chapter 1 is applied to dimers of dipolar chromophores in a unified and comprehensive picture able to describe both exciton delocalization in homodimers and resonance energy transfer in heterodimers.
In chapter 5, bigger and chiral aggregates are addressed, tackling the problem of chiral proline-derived squaraine aggregates. Squaraines represent a remarkable family of quadrupolar dyes whose aggregates show diverse and interesting properties, including the panchromatic absorption spectrum of nanoparticles and thin films. The general picture is far from clear, with the origin of these peculiar features being alternatively attributed to either disorder or to intermolecular charge transfer (ICT) interactions. A new set of experimental data comprising absorption and circular dichroism spectra of a series of chiral proline-derived squaraine aggregates adds a further piece to the puzzle. In the attempt to elucidate the role of disorder and intermolecular charge transfer, an essential state model extended to account for ICT is used to address chiroptical properties of the aggregates at hand. While a firm conclusion is not yet reached, significant insights are obtained about the physics of these intriguing and fascinating systems
Infant and maternal attachment : an ethological analysis in the Strange Situation
No full textIl rapporto precoce che va a instaurarsi tra la madre e il suo bambino può essere definito come
uno dei legami più intensi, viscerali, quindi determinanti presenti nella vita umana. Esso porta
con sé implicazioni che condizionano il bambino dalla sua infanzia, fino alla vita adulta. In
questo elaborato, l’obiettivo principale è stato quello di indagare la trasmissione
dell'attaccamento tra madre e figlio e comprendere come questa si sviluppi in un contesto di
interazione continua e reciproca, e come il modello di attaccamento materno influenzi
profondamente lo stile di attaccamento del bambino. Ma questa trasmissione è lineare? Quali
altri fattori intervengono nel modellare questo legame unico?
La teoria dell'attaccamento, sviluppata da Bowlby e arricchita dalle ricerche empiriche di
Ainsworth, fornisce una base solida per comprendere i meccanismi attraverso cui il legame
di attaccamento si forma e si evolve. Questo elaborato descrive innanzitutto le principali
teorie sull’attaccamento, analizzando la Strange Situation Procedure (SSP) come strumento
di valutazione e classificazione dei diversi stili di attaccamento: sicuro, evitante, ambivalente
(o resistente) e disorganizzato. L'analisi si è poi concentrata sulla trasmissione
intergenerazionale dello stile di attaccamento, cercando di capire come il modello di
attaccamento sviluppato dalla madre influenzi quello del bambino e in che misura tale
influenza possa essere mediata da altri fattori, come il temperamento del bambino e il contesto
socio-relazionale.
Lo studio presentato si basa su un campione di diadi madre-bambino che hanno partecipato
al progetto Life-MILCH, adottando un approccio etologico quantitativo per misurare i
comportamenti di attaccamento durante la SSP. Attraverso un'analisi dettagliata della
frequenza e della durata dei comportamenti osservati, si è cercato di superare la rigida
categorizzazione tradizionale, abbracciando invece l’idea di un continuum di attaccamento,
in cui i comportamenti dei bambini si distribuiscono in maniera più fluida tra le diverse
categorie. Le ipotesi di ricerca includevano la possibilità che il temperamento infantile, pur
essendo un fattore rilevante, non fosse l’unico determinante dell'attaccamento, e che
l’attaccamento materno potesse interagire dinamicamente con le caratteristiche del bambino
nel determinare il suo stile di attaccamento. I risultati hanno mostrato che, pur confermando
in parte l'influenza del modello di attaccamento materno, la trasmissione dell'attaccamento
non è lineare ed è soggetta a molteplici influenze che devono essere ulteriormente indagate.
Questo studio è una dimostrazione di quanto l’attaccamento di una madre rappresenti una
base importante e lasci un’impronta capace di guidare il comportamento della stessa verso il
figlio, però allo stesso tempo vuole mettere in luce la complessità e la variabilità che c’è dietro
questo tipo di legame. Altri fattori quali il temperamento del bambino, la sensibilità materna
e quella paterna e più in generale il contesto socio-relazionale, giocano un ruolo cruciale, per
cui si rivela difficile comprendere la loro interazione e si rende necessaria un’analisi più
approfondita e di tipo multidisciplinare.The early relationship that develops between a mother and her child can be defined as one of the most intense, visceral, and therefore, determinant bonds in human life. It carries implications that affect the child from infancy to adulthood. In this work, the main objective was to investigate the transmission of attachment between mother and child and to understand how it develops in a context of continuous and reciprocal interaction, and how the maternal attachment model profoundly influences the child's attachment style. But is this transmission linear? What other factors contribute to shaping this unique bond?
Attachment theory, developed by Bowlby and enriched by the empirical research of Ainsworth, provides a solid foundation for understanding the mechanisms through which the attachment bond forms and evolves. This work first describes the main attachment theories, analyzing the Strange Situation Procedure (SSP) as a tool for assessing and classifying different attachment styles: secure, avoidant, ambivalent (or resistant), and disorganized. The analysis then focused on the intergenerational transmission of attachment style, seeking to understand how the attachment model developed by the mother influences that of the child and to what extent this influence can be mediated by other factors, such as the child's temperament and the socio-relational context.
The presented study is based on a sample of mother-child dyads who participated in the Life-MILCH project, adopting a quantitative ethological approach to measure attachment behaviors during the SSP. Through a detailed analysis of the frequency and duration of observed behaviors, this study sought to go beyond the rigid traditional categorization, instead embracing the idea of an attachment continuum, in which children's behaviors are more fluidly distributed across the different categories. The research hypotheses included the possibility that while infant temperament is a relevant factor, it is not the sole determinant of attachment, and that maternal attachment could dynamically interact with the child's characteristics in determining their attachment style. The results showed that while confirming, in part, the influence of the maternal attachment model, the transmission of attachment is not linear and is subject to multiple influences that need further investigation.
This study demonstrates how a mother's attachment represents an important foundation, leaving an imprint capable of guiding her behavior towards her child, but at the same time aims to highlight the complexity and variability behind this type of bond. Other factors such as the child's temperament, maternal and paternal sensitivity, and more generally the socio-relational context, play a crucial role, making it difficult to understand their interaction and necessitating a more in-depth and multidisciplinary analysis
Seasonal variations of milk quality in cattle heards
No full textThe following thesis aims to assess the variation of milk quality throughout the seasons and
over the years in a dairy farm producing milk for Grana Padano cheese.
To this objective, 101 herd milk samples collected during 3 years (2020, 2021, 2022; 2 samples
per month) were analyzed for their variations according to season and year.
In terms of processing properties, over the years, the milk produced shows a gradual
deterioration in quality due to significant declines in fat and protein contents. As expected, the
protein content decrease in the summer period and, surprisingly, it does not change in the
following fall season.
In terms of animal health and hygiene quality of milk, the study shows that total bacterial count
and somatic cell count values show significant variations over the years. However the average
values were below legal limits.
L’obiettivo di questa tesi è valutare l’effetto della stagione e dell’anno sulla qualità del latte prodotto in una stalla che conferisce latte per la produzione di formaggio Grana Padano.
A tal fine, sono stati raccolti 101 campioni di latte di allevamento al 2020 al 2022n (2 campioni
al mese) ed è stato indagato l’effetto della stagione e dell’anno.
Sotto il profilo tecnologico-caseario, nel corso degli ultimi anni, il latte prodotto mostra un
graduale peggioramento a causa dei cali significativi del contenuto di grasso e proteine. Come
atteo, il contenuto di proteina è calato significativamente in estate. Sorprendentemente, non si
è osservata una ripresa dei tenori proteici in autunno, in cui si sono registrati valori analoghi a
quelli estivi.
Sotto il profilo igienico-sanitario, seppur sono stati evidenziati variazioni annuali del contenuto
delle cellule somatiche e della carica batterica totale, i valori osservati sono risultati comunque
al di sotto dei limiti di legge
Spatial Neglect and Mirror Rehabilitation : an experimental study on a single patient
No full textIl neglect spaziale è una patologia sfaccettata ancora da comprendere dal punto di vista fenomenologico e neurofisiologico. Si può suddividere la sintomatologia in base alla distanza dall’osservatore (personale, peripersonale, extrapersonale), al punto di vista adottato (allocentrico, egocentrico) e ai sensi coinvolti (visivo, uditivo, tattile). La diagnosi risulta complessa, infatti la variabilità del tasso d’occorrenza in letteratura è elevata (20%~80%). La riabilitazione non risulta semplice e non è possibile stabilire un “gold standard” dalle evidenze in letteratura. In questa tesi è affrontato il caso clinico di una paziente (A.B.) che ha sviluppato neglect spaziale a seguito di un evento ischemico. È stato progettato un protocollo di mirror therapy fondato sull’evidenza in letteratura per il trattamento della sintomatologia cronica di A.B. Le valutazioni, quantitativa e qualitativa, al post-training e al follow-up (3 mesi) sembrano rilevare l’efficacia dell’intervento riabilitativo, ma è necessaria l’implementazione di studi sistematici, con controlli adeguati, per generalizzare il protocollo ai pazienti con neglect spaziale.Spatial neglect is a multifaceted disorder that has yet to be fully understood both phenomenologically and neurophysiologically. The symptomatology can be subdivided based on the distance from the observer (personal, peripersonal, extrapersonal), the perspective adopted (allocentric, egocentric), and the senses involved (visual, auditory, tactile). Diagnosing it is complex, and the reported occurrence rates in the literature vary significantly (20%–80%). Rehabilitation is also challenging, and it is not possible to establish a “gold standard” based on the current evidence. This thesis presents the clinical case of a patient (A.B.) who developed spatial neglect following an ischemic event. An evidence-based mirror therapy protocol was designed to address A.B.’s chronic symptoms. Quantitative and qualitative assessments at post-training and follow-up (3 months) suggest the effectiveness of the rehabilitation intervention. However, systematic studies with proper controls are needed to generalize the protocol to patients with spatial neglect.
Behavioural comorbidities in canine idiopathic epilepsy
No full textCi sono diversi tipi di epilessia, tra i quali il più comune nei cani e l'epilessia idiopatica, la cui origine e comprovata o sospetta genetica e molte razze presentano una predisposizione ereditaria a svilupparla. Tra queste sono riportate Border Collie, Labrador Retriever, San Bernardo, Pastore tedesco, Boxer, Lagotto Romagnolo e Golden Retriever.
La diagnosi di epilessia idiopatica si fa per esclusione e ci sono tre livelli di confidenza (Tier I, II, III) che permettono l'esclusione di alterazioni strutturali.
Al di la dei sintomi legati all'epilessia, sono state riportate nel cane come in medicina umana delle comorbidità comportamentali, causate totalmente dalla malattia o parzialmente dalle terapie antiepilettiche.
Le informazioni riguardo alle alterazioni comportamentali nei cani affetti da epilessia idiopatica sono state raccolte prevalentemente tramite questionari proposti ai proprietari (o test pratici negli studi sulla disfunzione cognitiva). Sono stati riportati in letteratura: paura e ansia, aggressività , disturbo dell'attaccamento, reazioni anomale, diminuzione dell'addestrabilità (valutata considerando deficit dell'attenzione, eccitabilità /impulsività e perdita di interesse nei confronti di attività proposte), alterazione della percezione, disfunzione cognitiva e apatia.
Queste comorbidità hanno spesso ripercussioni negative sulla qualità di vita del cane e del suo proprietario e sarebbe quindi importante approfondirne la conoscenza in modo che possano essere meglio caratterizzate e riconosciute nel paziente. La diagnosi di questi problemi comportamentali permette al neurologo di intervenire terapeuticamente, eventualmente con l'aiuto di comportamentalisti, con interventi farmacologici e non. In particolare, trattamenti non farmacologici comprendono in primis un approccio comportamentale e di addestramento, oltre che una terapia dietetica, dal momento che alcuni studi hanno riportato effetti benefici di alcune diete non solo sul comportamento ma anche sull'epilessia primaria.There are different types of epilepsy and idiopathic epilepsy is the most common type in dogs. It generally has a proven or suspected genetic cause, and many breeds have a hereditary predisposition to develop it (e.g. Border Collie, Labrador Retriever, Saint Bernard, German Sheperd, Boxer, Lagotto Romagnolo, and Golden Retriever). It is a diagnosis of exclusion based on three levels of confidence (Tier I, II and III), which exclude any structural anomalies.
Other than the pure epileptic symptoms, both human and canine epilepsy implicates behavioural comorbidities, ascribable to the neurological disease itself or partially to the antiepileptic drugs used to treat it.
The alterations registered in dogs with idiopathic epilepsy, mainly assessed through questionnaires to the owners (and tests for the studies on cognitive dysfunction) were fear and anxiety, aggressivity, attachment disorder, abnormal reactivity, decreased trainability (with attention deficits, excitability/impulsivity and loss of excitement for activities), abnormal perception, cognitive impairment and apathetic behaviour.
These comorbidities can have a negative effect on the quality of life of the dog and its carer, and for this reason they should be further studied in order to better characterize them and recognize them. The diagnosis of behavioural problems allows the neurologist to treat them, eventually with the help of behaviourists, either with medical or non-medical therapies, such as training and behavioural approaches, and diets (which have been reported as beneficial for seizure treatment as well)
Uno studio sull'insorgenza di grandi fluttuazioni in Teoria delle Perturbazioni Numerico Stocastica
No full textPerturbation theory is universally recognized as a fundamental tool in modern theoretical physics. In the functional integral formalism, perturbation theory provides a method for studying field theories, offering both mathematical rigor and substantial physical insights. It is challenging to name an area of theoretical physics where perturbation theory does not play a fundamental role: even in theories specifically designed for a non-perturbative approach like lattice gauge theories, perturbation theory remains relevant and interesting. Lattice gauge theories offer a powerful framework for understanding non-perturbative aspects of quantum field theories. By discretizing space-time on a lattice, these theories enable detailed Monte Carlo simulations that are crucial for probing phenomena beyond the reach of perturbation theory, shedding light on subtle features such as quark confinement in QCD and many others. In the mid-1990s, a new method was developed that in a sense integrates traditional perturbation theory with Monte Carlo simulations of lattice field theories (in particular lattice gauge theories, for which traditional diagrammatic perturbation theory is cumbersome). This approach is known as Numerical Stochastic Perturbation Theory (NSPT). NSPT offers a fully automated stochastic method for calculating loop corrections in lattice field theories, using the power of Monte Carlo simulations. Its numerical implementation requires minimal changes with respect to traditional Monte Carlo simulations; (also due to this) NSPT enables the calculation of loop corrections at very high perturbative orders. The ease of implementation and advanced capability explain why NSPT has captured the attention of lattice practitioners. A not-well explored feature of NSPT is the freedom to choose any vacuum for calculating perturbation theory, in principle without encountering the complexities of the diagrammatic perturbation theory. If one had to make a natural choice, low-dimensional models are the best candidates for exploratory analysis of the feasibility of perturbative expansions on top of non-trivial vacua. This way, one immediately encounters problems: it is known that NSPT simulations exhibit large fluctuations in low-dimensional models. As the perturbative order increases, huge fluctuations show up, completely obscuring the signal at even not-so-high perturbative orders.
In this thesis, we discuss NSPT simulations for a class of highly interesting low-dimensional models, the two-dimensional O(N) Non-Linear Sigma Models (NLSMs). O(N) non-linear sigma models can be regarded as a valuable theoretical laboratory in quantum field theory, as they display in a relatively simple framework interesting features like asymptotic freedom. From a more phenomenology oriented point of view, NLSM proved to be effective in modeling different features in different contexts. As we will see, in this work our interest for O(N) models is motivated by the possibility to tune N. On general grounds we expect that huge
fluctuations in simulations of low-dimensional models are somehow connected to the limited number of degrees of freedom. From this perspective, O(N) NLSMs are an ideal laboratory: in fact we can modify the number of degrees of freedom by tuning the parameter N. Our numerical results show that in the large N limit NSPT simulations are not affected by the large fluctuations issue at high orders, in contrast to what occurs in the small N regime. Our conclusions are supported by extensive numerical studies of the properties of NSPT distributions as function of the perturbative order n and the parameter N. While a fundamental comprehension is admittedly lacking, we will consider different indicators for assessing if (and to what extent) large enough N computations are to be regarded as safe at a given perturbative order n. In particular, the study of relative errors has been particularly fruitful: in this context, the onset of fluctuations has been probed through violations of very generally expected scaling behaviors. Our numerical simulations strongly suggest that indeed for each perturbative order n, an NSPT computation in O(N) can always be found safe with respect to fluctuations if we take a large enough N. As a result, the larger the value of N, the more perturbative corrections we could compute, significantly extending the previously known results from lattice diagrammatic perturbation theory.
Once for large enough N high perturbative orders can be safely computed, we expect we can explore the asymptotic behavior of perturbative expansions. In the context of lattice gauge theories, NSPT has proven to be effective in probing infrared renormalons. In the final part of the thesis, we discuss O(N) renormalon effects in the large N limit. We will perform computations on a pretty small lattice size, but we will provide new insights on the role of finite-volume effects. In particular, by explicitly taking into account the infrared cutoff, we obtained an analytic (first-principles) estimate of finite-volume effects, assessing how they modify the factorial scaling of coefficients. Once we have such a modeling, we can compare analytical predictions and numerical results, finding agreement in the asymptotic perturbative region. We stress that this will be a parameter-free comparison (there is no space for any parameter to adjsut). Large N NSPT simulations for O(N) models can also be regarded as a preliminary step towards going back to perturbative expansions around non-trivial vacua. Quite interestingly, such computations in the (quite close) CP(N-1) models are connected to resurgence scenarios
Ozone as antimicrobial: applications in the treatment of infectious diseases in farm animals
No full textNegli ultimi vent'anni, si è registrato un crescente interesse da parte dei veterinari per la terapia con ozono, spinto dalla necessità di esplorare alternative terapeutiche a causa dell'aumento della resistenza agli antibiotici. Questo lavoro analizza la letteratura sull'applicazione dell'ozono nel trattamento delle malattie infettive negli animali da reddito, concentrandosi su patologie come la mastite, l'endometrite e il marciume del piede, considerando gli articoli pubblicati dal 2000 al 2023. Lo studio esamina i diversi metodi di somministrazione, le concentrazioni utilizzate e i protocolli terapeutici adottati. I risultati ottenuti evidenziano le promettenti proprietà antimicrobiche dell'ozono, suggerendo la sua potenziale efficacia come alternativa alla terapia antibiotica. Inoltre, studi recenti hanno dimostrato che l'uso combinato di ozono e antibiotici può migliorare gli esiti clinici. Considerando l'ampia gamma di applicazioni dell'ozono, l'obiettivo di questa revisione è esaminare i suoi meccanismi d'azione e il suo utilizzo nelle diverse specie animali, come bovini e piccoli ruminanti. Saranno necessarie ulteriori ricerche e studi clinici, controllati e standardizzati, in grado di superare le differenze tra i protocolli per validare l'efficacia e la sicurezza della terapia con ozono.In the last twenty years, there has been a growing interest among veterinarians in ozone
therapy, driven by the need to explore therapeutic alternatives due to the increase in
antibiotic-resistance. This work analyzes the literature on the application of ozone in the
treatment of infectious diseases in farm animals, focusing on conditions such as mastitis,
endometritis, and foot rot, considering articles published from 2000 to 2023. The study
examines the different administration methods, the concentrations used, and the
therapeutic protocols adopted. The results obtained highlight the promising antimicrobial
properties of ozone, suggesting its potential effectiveness as an alternative to antibiotic
therapy. Furthermore, recent studies have shown that the combined use of ozone and
antibiotics can improve clinical outcomes. Considering the wide range of applications of
ozone, the aim of this review is to examine its mechanisms of action and its use in the
different animal species, such as cattle and small ruminants. Further research and clinical
studies will be necessary, controlled and standardized, capable of overcoming the
differences between protocols to validate the efficacy and safety of ozone therapy
Congenital intra and extra cardiac shunts in cats
No full textGli shunt cardiaci congeniti, intra ed extra cardiaci, rappresentano una patologia rara ma significativa nel gatto con implicazioni rilevanti per la funzionalità cardiovascolare. Dopo una breve introduzione sulla fisiologia della funzionalità cardiaca, si presta particolare attenzione all’embriologia in quanto rappresenta la base concettuale per comprendere le alterazioni anatomiche che si riscontrano nelle varie patologie cardiache con shunt. Questo lavoro si propone quindi di prendere in esame caratteristiche, diagnosi e approccio terapeutico medico e chirurgico degli shunt cardiaci congeniti del gatto con l’obiettivo di fornire una sintesi chiara delle manifestazioni cliniche, delle metodologie diagnostiche in ecocardiografia e delle opzioni terapeutiche disponibili. Lo studio si basa sulla letteratura scientifica più recente, facendo riferimento anche ai fondamenti della cardiologia veterinaria degli anni ’90, e su evidenze ottenute da studi retrospettivi riportate da fonti terze.
Le conclusioni che si possono evincere da questo elaborato evidenziano la necessità di sviluppare protocolli diagnostici che permettano di individuare in modo precoce queste patologie, per poterle gestire in modo tempestivo ed efficace.Congenital cardiac shunts, both intra and extra cardiac, represent a rare but significant condition in cats with relevant implications for cardiovascular functionality. Following a brief introduction of the physiology of cardiac function, particolar attention is given to embriology, as it provides the conceptual foundation for the undestanding of the anatomical alterations observed in various cardiac shunt-related pathologies. The aim of this paper is to examine the caracteristics, diagnosis, and medical and surgical therapeutic approaches to congenital cardiac shunts in cats, with the goal of providing a clear synthesis of clinical manifestations, diagnostic methods in ecocardiography and therapeutic options. The study is based on the most recent scientific literature, also referencing to the foundamentals of veterinary cardiology from the 1990s, as well as evidence obtained from retrospective studies reported by third-party sources.
The conclusions drawn from this work highlight the need to develop diagnostic protocols that allow for the early identification of these conditions, so they can be managed promptly and effectively