On commodity trading strategies: momentum, term structure, maturity, indexation

The thesis investigates the presence of idiosyncratic characteristics in commodity futures markets that lead to profitable trading strategies, effectively testing the efficiency of commodity markets. First, short-term continuation and long-term reversal in commodity futures prices are examined. While contrarian strategies do not work, 13 profitable momentum strategies have been identified that generate 9.38% average return a year. On average the momentum strategies buy backwardated contracts and sell contangoed contracts. Testing the direct implication of this behavior, the strategy of buying the most backwardated and selling the most contangoed commodities is examined. With significant annualized alphas of 10.14% and 12.66% respectively the momentum and term structure strategies appear profitable when implemented individually. The thesis continues by investigating the combined role of momentum and term structure signals. With an abnormal return of 21.02%, our double-sort strategy that exploits both momentum and term structure signals clearly outperforms the single-sort strategies. The thesis continues by examining the role of momentum, term structure and time to maturity/expiry factors in the design of enhanced commodity indices. In a long-only framework the momentum parameterized Standard & Poor's Goldman Sachs Commodity Index (S&P- GSCI former GSCI) and Dow-Jones UBS Commodity Index (DJ-UBSCI former DJ-AIGCI) yield 0.46 and 0.9 times higher returns than the traditional S&P-GSCI and DJ-UBSCI respectively. The term structure parameterized S&P-GSCI and DJ-UBSCI exhibit 0.63 and 0.68 times higher returns respectively. The combined parameterized indices increase the outperformance by 0.65 and 1.02 times and the longer maturity indices yield on average 1.37 and 1.97 times higher returns than the traditional indices respectively. These findings can be exploited for diversification purposes in a long-only commodity world or deployed as a framework to facilitate choosing among commodity indices. Keywords: Commodity futures, Momentum, Term Structure, Backwardation, Contango, Diversification, Commodity indice

Electronic properties of graphene nanoribbons with defects

© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Graphene nanoribbons (GNRs) are the most important emerging Graphene structures for nanoelectronic and sensor applications. GNRs with perfect lattices have been extensively studied, but fabricated GNRs contain lattice defects the effect of which on their electronic properties has not been studied extensively enough. In this paper, we apply the Non-Equilibrium Green's function (NEGF) method combined with tight-binding Hamiltonians to investigate the effect of lattice defects on the conductance of GNRs. We specifically study, butterfly shaped GNRs, which operate effectively as switches, and have been used in CMOS-like architectures. The cases of the most usual defects, namely the single and double vacancy have been analytically examined. The effect of these vacancies was computed by placing them in different regions and with various numbers on GNR nano-devices, namely edges, main body, contacts and narrow regions. The computation results are presented in the form of energy dispersion diagrams as well as diagrams of maximum conductance as a function of the number of lattice defects. We also present results on the defect tolerance of the butterfly shaped GNR devices.Peer ReviewedPostprint (author's final draft

Current characteristics of defective GNR nanoelectronic devices

The most promising Graphene structures for the development of nanoelectronics and sensor applications are Graphene nanoribbons (GNRs). GNRs with perfect lattices have been extensively investigated in the research literature; however, fabricated GNRs may still suffering from lattice flaws, the possible effect of which, on the operation of the circuitry comprised by GNR based devices, has not attracted significant interest. In this paper, we investigate the effect of lattice defects on the operational behavior of GNRs using the Non-Equilibrium Green's function (NEGF) method combined with tight-binding Hamiltonians targeting to the resulting nanoelectronic devices and circuits functionalities. We focus on butterfly-shaped GNRs, which have been proven to successfully function as switches that can be used as building blocks for simple Boolean gates and logic circuits. Analyses of the most common defects, namely the single and double vacancies, have been adequately performed. The effect of these vacancies was investigated by inserting them in various places and concentrations on the corresponding GNR based nano-devices. The computation results indicate the effect on lattice defects on the important operational device parameters including the leakage current, ION/IOFF and, finally, current density, which will determine the viability of GNR computing circuits.Postprint (published version

Novel circuit design methodology with graphene nanoribbon based devices

© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Graphene has attracted a high amount of interest in recent years in many research fields, including the field of electronics. Due to its spectacular properties, it is investigated as a candidate material for the realization of nanodevices that will constitute conventional or even unconventional computing circuits. In this work, we explore the ability of Graphene Nanoribbon based topologies to create a universal computing set. We propose the design of an AND, OR and NOT gate, as well as the design of a Buffer, for the first time in a configuration similar to the Pass Transistor Logic (PTL) configuration. The valid operation of the proposed topologies is verified through accurate SPICE simulations, providing the ability to design combinational logic using Graphene, based on PTL methodology.This research was supported in part by the Spanish MCIN/AEI/10.13039/501100011033, Project PID2019-103869RB-C33 and grant 391 (with the support of the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya)Peer ReviewedPostprint (published version

A reprogrammable graphene nanoribbon-based logic gate

© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In this article, taking into consideration the exceptional technological properties of a unique 2-D material, namely Graphene, we are envisioning its usage as the structure material of a non-back-gated re-programmable switching device. The proposed topology is analyzed in depth, not only by verifying its operation and re-programmability as a 2-input XOR , 3-input XOR and 3-input Majority gate, but also by examining its computing performance in terms of area, delay and power dissipation. More specifically, we are utilizing L-shaped Graphene Nanoribbons (GNRs) to develop comb-shaped Graphene based switching devices. These devices are in position with effective programming through biasing to design any combinatorial circuit as resulting from the aforementioned universal set of Boolean gates. The resulting figures of merit regarding the area with a universal footprint of 2.53 nm2 for every gate independently of the number of inputs, the propagation delay with 2.05×10-2ps and, last but not least, the power dissipation with only 10.204 nW for the gates with greater number of inputs, are quite encouraging and promising. Moreover, the ability of the proposed topology to pave the way towards the implementation of basic circuits has been further investigated, by demonstrating an example of a 1-bit full adder cell and its sufficient operation arriving from the corresponding successful SPICE simulation results.Peer ReviewedPostprint (author's final draft

Angiomyofibroblastoma of the spermatic cord: a case report

<p>Abstract</p> <p>Introduction</p> <p>Angiomyofibroblastoma is a benign soft tissue tumor with tendency to arise in the vulva.</p> <p>Case presentation</p> <p>We report a 36-year-old Greek Caucasian man presenting with a left inguinal painless mass. This is the second case of angiomyofibroblastoma of the spermatic cord. At operation, a 4.5 cm well-circumscribed solid tumor was found adherent to the spermatic cord. The tumor consisted of spindle-shaped cells proliferating in short fascicles between numerous medium-sized blood vessels with thin and hyalinized walls. Neoplastic cells had eosinophilic cytoplasm with neither mitotic figures nor nuclear atypia. The stroma included abundant mast cells and few mature lypocytes. Immunostaining showed positivity for vimentin, CD34, desmin and smooth muscle actin. Our patient was treated by simple excision and was followed up for five years with clinical examination and ultrasonography, revealing no evidence of local recurrence or metastasis.</p> <p>Conclusion</p> <p>This unusual neoplasm should be distinguished from aggressive angiomyxoma and other myxoid malignant tumors with widespread metastatic potential.</p

On commodity trading strategies : momentum, term structure, maturity, indexation

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Εφαρμογή της ετιδοκαΐνης στην οδοντιατρική: κλινική έρευνα

The purpose of this clinical research, was to investigate the anaesthetic value of a new local anaesthetic agent, etidocaine and its comparison with lignocaine which today, is regarded as the anaesthetic of first selection.Με την κλινική αυτή έρευνα, επιδιώχθηκε ο έλεγχος της αναισθητικής ικανότητας ενός νέου τοπικού αναισθητικού, της ετιδοκαΐνης και η ταυτόχρονη σύγκριση της με τη λιγνοκαΐνη, που σήμερα θεωρείται το αναισθητικό πρώτης επιλογή

The effect of incisional biopsy on metastases of oral carcinoma: An animal study

Aim: This animal study researches the effect of biopsy on metastasis of oral squamous cell carcinoma. Materials and Methods: Sixty male Syrian golden hamsters developed oral tumors after treatment with 9,10-dimethyl-1,2-benzanthracene for a period of 14 weeks and were then divided into six equal groups. Animals of control groups 1 and 2 did not receive any further treatment, while groups 3-6 were biopsied at the end of the 14th week and groups 5 and 6 also received a prebiopsy intratumoral injection of bleomycin. Animals of groups 1, 3, 5 and 2, 4, 6 were sacrificed at the 17th and 19th week respectively. Specimens of tumors, ipsilateral cervical lymph nodes, lungs and livers were obtained from all animals and histologically examined. Results: All animals developed oral squamous cell carcinomas. In group 4, four out of ten animals showed metastases to the cervical lymph nodes, and one out of four showed a distant metastasis to the lung. Conclusions: Delay of treatment up to 5 weeks following biopsy, can increase the risk of cervical lymph node metastasis, which can be reduced by an intratumoral administration of bleomycin.Σκοπός: Η μελέτη της επίδρασης της μερικής βιοψίας στη διασπορά των καρκινικών κυττάρων ακανθοκυτταρικού καρκινώματος του στόματος σε πειραματόζωα. Υλικά και μέθοδος: Εξήντα αρσενικά Syrian golden hamsters ανέπτυξαν όγκους του στόματος μετά τη χρήση 9,10-διμεθυλ-1,2-βενζανθρακένιου για 14 εβδομάδες και ακολούθως χωρίστηκαν σε έξι ίσες ομάδες. Τα πειραματόζωα των ομάδων ελέγχου 1 και 2 δεν δέχτηκαν καμία περαιτέρω θεραπεία, ενώ τα πειραματόζωα των ομάδων 3-6 υπέστησαν βιοψία των όγκων στο τέλος της 14ης εβδομάδος και επιπρόσθετα στα πειραματόζωα των ομάδων 5 και 6 έγινε έγχυση διαλύματος υδροχλωρικής μπλεομυκίνης στη βάση του δημιουργηθέντος όγκου λίγο πριν τη βιοψία. Τα πειραματόζωα των ομάδων 1, 3, 5 and 2, 4, 6 θυσιάστηκαν την 17η και την 19η εβδομάδα αντίστοιχα. Δείγματα από τους όγκους, τους σύστοιχους τραχηλικούς λεμφαδένες, τους πνεύμονες και το ήπαρ ελήφθησαν από όλα τα πειραματόζωα και εξετάστηκαν ιστοπαθολογικά.Αποτελέσματα: Όλα τα πειραματόζωα ανέπτυξαν ακανθοκυτταρικό καρκίνωμα του στόματος. Στην ομάδα 4, τέσσερα από τα δέκα πειραματόζωα εμφάνισαν μεταστάσεις στους σύστοιχους τραχηλικούς λεμφαδένες και επιπροσθέτως ένα από τα τέσσερα εμφάνισε απομεμακρυσμένη μετάσταση στον πνεύμονα. Συμπεράσματα: Η κατά 5 εβδομάδες καθυστέρηση στην εφαρμογή χειρουργικής θεραπείας, αυξάνει σημαντικά τον κίνδυνο μετάστασης στους επιχώριους τραχηλικούς λεμφαδένες, γεγονός που μπορεί να μειωθεί σημαντικά μετά την έγχυση εντός του όγκου μπλεομυκίνης