Le stagioni degli amori e delle nascite di Propithecus verreauxi: comportamenti a confronto

Propithecus verreauxi, appartenente alla famiglia Indriidae, è una specie di proscimmia diurna endemica del Sud e del Sud-Ovest del Madagascar, caratterizzata da un sistema sociale di tipo multi-male/multi-female a dominanza femminile (Jolly, 1966). Il ciclo riproduttivo strettamente stagionale di Propithecus verreauxi prevede che gli accoppiamenti si concentrino all’interno della stagione umida, durante la quale le risorse alimentari sono abbondanti, mentre le nascite si verificano all’interno della stagione secca, nel periodo di scarsità di cibo (Jolly, 1966; Richard et al., 2000). Lo scopo del mio studio è quello di analizzare le dinamiche sociali in una specie altamente stagionale come Propithecus verreauxi, misurando quantitativamente i comportamenti sociali, olfattivi e agonistici che la caratterizzano e osservando come questi varino in relazione alla stagione considerata. Tra i comportamenti sociali, il grooming è stato analizzato come possibile indicatore dei rapporti che intercorrono tra maschi e femmine nel periodo riproduttivo, in cui il conflitto di interessi tra i due sessi è elevato. La distribuzione di questo comportamento tra le due stagioni ha indicato anche una sua possibile funzione, ovvero quella di “merce di scambio” per l’accesso alle femmine in estro (mating market) (Barrett e Henzi, 2001; Noë e Hammerstein, 1994, 1995; Hemelrijk et al., 1992; Colmenares et al., 2002). Tenendo conto del “bimorfismo sessuale” che caratterizza i maschi di Propithecus verreauxi, abbiamo esaminato come l’attività di grooming, effettuata dai maschi verso le femmine, potesse variare in rapporto allo status sociale del maschio. I maschi subordinati mostrano una maggiore attività di grooming nella stagione riproduttiva. Dato che il comportamento olfattivo riveste un ruolo fondamentale per la comunicazione in questa specie abbiamo esaminato come l’attività di sniffing e di overmarking dei maschi variassero in base al tipo di marcatura deposta dalle femmine, ottenendo risultati che indicano che l’urina femminile potrebbe essere altamente informativa a proposito del loro stato riproduttivo. Le interazioni aggressive sono numerose solo nella stagione riproduttiva, in cui l’ottenimento dell’accoppiamento diventa lo scopo principale di ogni individuo e inasprisce le relazioni inter-individuali. La società di tipo non despotico e le relazioni sociali tipicamente tolleranti di questa specie si manifestano nel basso livello di conflitti nella stagione nascite e nel venir meno della gerarchia lineare che contraddistingue il periodo riproduttivo

Implementazione, creazione e ottimizzazione di una pipeline per l'analisi biofisica su cluster a basso consumo energetico.

In questa tesi si è studiata l'efficienza computazionale di nodi di calcolo a basso consumo energetico per l'analisi biofisica, confrontati con nodi tradizionali. Questo lavoro è parte di un progetto per valutare la fattibilità dell'utilizzo di macchine a basso consumo energetico per calcolo ad alta performance. Lo scopo della ricerca è provare che l'utilizzo di cluster low power possa fornire una potenza di calcolo confrontabile con quelli tradizionali. Il sistema su cui si è concentrato il lavoro di tesi è uno dei metodi più recenti nella ricerca sulle mutazioni genetiche che sono cause di vari tipi di tumori: il sistema GATK-LODn. Nel corso della tesi è stata reimplementata una componente di questo metodo in una pipeline nel programma Snakemake, che ha permesso una gestione più accurata delle operazioni previste per ottimizzare l'esecuzione complessiva. Questa tesi prende in esame questo algoritmo di bioinformatica per valutare se è realmente possibile confrontare le capacità dei nodi low power con quelli tradizionali, in quanto questo richiede alte prestazioni computazionali, di memoria e capacità di storage. Nel primo capitolo saranno spiegati gli elementi del progetto. Sarà esposto il metodo GATK-LODn. Sarà poi descritta la parte del metodo che è stata reimplementata tramite Snakemake e saranno approfondite le capacità di questo strumento. Infine, sarà spiegato il significato di "nodo low power" e saranno descritte le caratteristiche dei nodi adoperati nelle analisi. Nel secondo capitolo sarà spiegato il funzionamento del programma, approfondendo i parametri utilizzati, e verranno evidenziati i passaggi necessari per un corretto uso del metodo. In più, saranno descritte le fasi dello studio statistico e sarà spiegata la tipologia di simulazioni effettuate. Infine verrano discussi i risultati finali più rilevanti per ciascuna regola della pipeline in termini di tempi di esecuzioni e memoria occupata

«In King Cambyses’ Vein»: Reconsidering the Relationship between Thomas Preston’s Cambises and Herodotus

The relationship between Thomas Preston’s early Elizabethan tragedy Cambises (printed 1569) and the Book III of Herodotus’ Histories has often been downplayed, owing to the lack of printed editions or translations of Herodotus in England at the time and the much more evident connection between the tragedy and the second book of Richard Taverner’s Garden of Wysedome (1547). However, a closer look at the play’s sources reveals how a connection may exist, and how the version of the story Preston staged may be influenced by the tale of Cambyses as presented by the ancient historian. The insistence on the relationship between the king and his subjects (a central issue in both Preston’s tragedy and its sources) may derive from Herodotus, especially if viewed in contrast with the previous versions of the story in medieval literature, the focus of which was mainly on the ethical exempla they provided. Through a comparison of those texts, and a consideration of the availability of Herodotus’ work at the time, either in print or in manuscript form, this paper will then suggest that the version Preston staged in his tragedy is closer to Herodotus than the previous literary tradition

Estimation of biological vascular ageing via photoplethysmography: a comparison between statistical learning and deep learning

This work aims to exploit the biological ageing phenomena which affects human blood vessels. The analysis is performed starting from a database of photoplethysmographic signals acquired through smartphones. The further step involves a preprocessing phase, where the signals are detrended using a central moving average filter, demoduled using the envelope of the analytic signal obtained from the Hilbert transform, denoised using the central moving average filter over the envelope. After the preprocessing we compared two different approaches. The first one regards Statistical Learning, which involves feature extraction and selection through the usage of statistics and machine learning algorithms. This in order to perform a classification supervised task over the chronological age of the individual, which is used as a proxy for healthy/non healthy vascular ageing. The second one regards Deep Learning, which involves the realisation of a convolutional neural network to perform the same task, but avoiding the feature extraction/selection step and so possible bias introduced by such phases. Doing so we obtained comparable outcomes in terms of area under the curve metrics from a 12 layers ResNet convolutional network and a support vector machine using just covariates together with a couple of extracted features, acquiring clues regarding the possible usage of such features as biomarkers for the vascular ageing process. The two mentioned features can be related with increasing arterial stiffness and increasing signal randomness due to ageing

A fresh look at the (non-)Abelian Landau-Khalatnikov-Fradkin transformations

The Landau-Khalatnikov-Fradkin transformations (LKFTs) allow to interpolate $n$-point functions between different gauges. We first offer an alternative derivation of these LKFTs for the gauge and fermions field in the Abelian (QED) case when working in the class of linear covariant gauges. Our derivation is based on the introduction of a gauge invariant transversal gauge field, which allows a natural generalization to the non-Abelian (QCD) case of the LKFTs. To our knowledge, within this rigorous formalism, this is the first construction of the LKFTs beyond QED. The renormalizability of our setup is guaranteed to all orders. We also offer a direct path integral derivation in the non-Abelian case, finding full consistency.Comment: 16 page

Homotopy data as part of the lattice field: A first study

Fields exhibit a variety of topological properties, like different topological charges, when field space in the continuum is composed by more than one topological sector. Lattice treatments usually encounter difficulties describing those properties. In this work, we show that by augmenting the usual lattice fields to include extra variables describing local topological information (more precisely, regarding homotopy), the topology of the space of fields in the continuum is faithfully reproduced in the lattice. We apply this extended lattice formulation to some simple models with non-trivial topological charges, and we study their properties both analytically and via Monte Carlo simulations.Comment: We added some references and a section where we make contact between the extended lattice formalism and the usual lattice variables augmented with an integer lattice field in the dual lattice. We made some corrections, including changing the title and the abstract, after referee's corrections and critique

Affinity chromatography of ovine casein

Abstract Sheep milk casein was separated into two fractions: one containing α s1 -plus β- and the other α s2 plus κ-caseins by affinity chromatography on activated thiol-Sepharose 4B. Milk samples were from the Leccese breed with the most common electrophoretic pattern. Electrophoresis of the chromatographic fractions on SDS-PAGE and on starch urea gel at pH 8.6 and 1.7 clarified the electrophoretic pattern of whole casein. Acidic pH electrophoresis of the two fractions obtained by affinity chromatography may be useful for investigations on the polymorphism of the casein fractions

Sialosignaling: Sialyltransferases as engines of self-fueling loops in cancer progression

Background Glycosylation is increasingly recognized as one of the most relevant postranslational modifications. Sialic acids are negatively charged sugars which frequently terminate the carbohydrate chains of glycoproteins and glycolipids. The addition of sialic acids is mediated by sialyltransferases, a family of glycosyltransferases with a crucial role in cancer progression. Scope of the review To describe the phenotypic and clinical implications of altered expression of sialyltransferases and of their cognate sialylated structures in cancer. To propose a unifying model of the role of sialyltransferases and sialylated structures on cancer progression. Major conclusions We first discuss the biosynthesis and the role played by the major cancer-associated sialylated structures, including Thomsen-Friedenreich-associated antigens, sialyl Lewis antigens, \u3b12,6-sialylated lactosamine, polysialic acid and gangliosides. Then, we show that altered sialyltransferase expression in cancer, consequence of genetic and epigenetic alterations, generates a flow of information toward the membrane through the biosynthesis of aberrantly sialylated molecules (inside-out signaling). In turn, the presence of aberrantly sialylated structures on cell membrane receptors generates a flow of information toward the nucleus, which can exacerbate the neoplastic phenotype (outside-in signaling). We provide examples of self-fueling loops generated by these flows of information. General significance Sialyltransferases have a wide impact on the biology of cancer and can be the target of innovative therapies. Our unified view provides a conceptual framework to understand the impact of altered glycosylation in cancer

Polarization properties of methanol masers

(Abridged) Astronomical masers have been effective tools to study magnetic fields for many years. In particular, methanol can be used to probe different parts of protostars such as accretion discs and outflows, since it produces one of the strongest and the most commonly observed masers in massive star-forming regions. We investigate the polarization properties of selected methanol maser transitions in light of newly calculated methanol Land\'e g-factors and considering hyperfine components. We compare our results with previous observations and we evaluate the effect of preferred hyperfine pumping and non-Zeeman effects. We run simulations using the radiative transfer code CHAMP. We find a dependence of linear and circular polarization fractions on the hyperfine transitions. Preferred hyperfine pumping can explain some high levels of linear and circular polarization and some of the peculiar features seen in the S-shape of observed V-profiles. Methanol masers are not significantly affected by non-Zeeman effects. Our models show that for methanol maser emission, both the linear and circular polarization percentages depend on which hyperfine transition is masing and the degree to which it is being pumped. Since non-Zeeman effects become more relevant at high values of brightness temperatures, it is important to obtain good estimates of these quantities and on maser beaming angles. Better constraints on the brightness temperature will help in understand about the extent to which non-Zeeman effects contribute to the observed polarization percentages. In order to detect separate hyperfine components, an intrinsic thermal line width significantly smaller than the hyperfine separation is required.Comment: Accepted for publication in Astronomy & Astrophysic