On the Marxian law of the falling rate of profit and Marx-biased technical change

Karl Marx was one of the first analysts of capitalism’s trends and problems. Here I offer a formal exposition of his thesis that the rate of profit tends to fall as a consequence of capital accumulation and analyze the most well-known counter-arguments. I then use the framework developed in the text to suggest a particular standpoint from which to look at development policy.

Novel Photocatalytic Approaches for Ecosustainable Synthesis

Over the past decades, photochemical synthesis, i.e. organic synthesis that uses light as source of energy to break and forge bonds, has vehemently re-emerged as an important theme of research in ecosustainable organic chemistry. Thanks to the possibility to excite a precise functional group in a complex reaction mixture and the peculiar reactivity of the so-formed excited states, photochemistry is very attractive for both synthetic researchers and industrial practitioners. An added value to this activation manifold is represented by photocatalysis: in these reactions, the substrate does not absorb light directly, instead low-energy light is absorbed by a purposely added molecule (photocatalyst, PC) that converts this energy into chemical energy for substrate activation, thus limiting undesired processes. This activation step can occur via Single-Electron Transfer (SET), Hydrogen-Atom Transfer (HAT) or Energy Transfer (ET) and in the present thesis I decided to study their application to develop novel ecosustainable synthetic protocols

Targeting Transcription-Coupled DNA Supercoiling for Discovery of Bacterial DNA Gyrase Inhibitors

Antibiotic production has been stagnant in the recent decade in comparison to the 30-years before that. The emergence of multidrug resistant bacteria is of mounting importance and a universal problem. The stagnation of antibiotic production, in part, is due to the lack of innovation in creating highly specific screening tools. Bacterial DNA gyrase is a type II topoisomerase that introduces negative supercoils into DNA, an essential mechanism for bacteria but absent from eukaryotes, making it an ideal target for identifying antibacterial compounds. In this study, we have constructed an E. coli strain FL#1181 that contains a pair of divergently coupled PgyrA and PT7A1/O4 promoters controlling the luc and lacZ genes at the attTn7 site of the E. coli chromosome. Since transcription-coupled DNA supercoiling (TCDS) provided by a strong IPTG-inducible promoter, such as the T7A1/O4 promoter (PT7A1/O4), is capable of potently inhibiting the divergently coupled, supercoiling-sensitive gyrA promoter (PgyrA), our results showed that DNA gyrase inhibitors greatly “enhanced” the expression of the firefly luciferase under the control of the divergently coupled, supercoiling-sensitive PgyrA. As a result, the luminescence generated from the firefly luciferase was significantly increased. This unique property of FL#1181 was used to screen a library containing ~30 different DNA-binding compounds

High resolution radargrammetry with COSMO-SkyMed, TerraSAR-X and RADARSAT-2 imagery: development and implementation of an image orientation model for Digital Surface Model generation

Digital Surface and Terrain Models (DSM/DTM) have large relevance in several territorial applications, such as topographic mapping, monitoring engineering, geology, security, land planning and management of Earth's resources. The satellite remote sensing data offer the opportunity to have continuous observation of Earth's surface for territorial application, with short acquisition and revisit times. Meeting these requirements, the SAR (Synthetic Aperture Radar) high resolution satellite imagery could offer night-and-day and all-weather functionality (clouds, haze and rain penetration). Two different methods may be used in order to generate DSMs from SAR data: the interferometric and the radargrammetric approaches. The radargrammetry uses only the intensity information of the SAR images and reconstructs the 3D information starting from a couple of images similarly to photogrammetry. Radargrammetric DSM extraction procedure consists of two basic steps: the stereo pair orientation and the image matching for the automatic detection of homologous points. The goal of this work is the definition and the implementation of a geometric model in order to orientate SAR imagery in zero Doppler geometry. The radargrammetric model implemented in SISAR (Software per Immagini Satellitari ad Alta Risoluzione - developed at the Geodesy and Geomatic Division - University of Rome "La Sapienza") is based on the equation of radar target acquisition and zero Doppler focalization Moreover a tool for the SAR Rational Polynomial Coefficients (RPCs) generation has been implemented in SISAR software, similarly to the one already developed for the optical sensors. The possibility to generate SAR RPCs starting from a radargrammetric model sounds of particular interest since, at present, the most part of SAR imagery is not supplied with RPCs, although the RPFs model is available in several commercial software. Only RADARSAT-2 data are supplied with vendors RPCs. To test the effectiveness of the implemented RPCs generation tool and the SISAR radargrammetric orientation model the reference results were computed: the stereo pairs were orientated with the two model. The tests were carried out on several test site using COSMO-SkyMed, TerraSAR-X and RADARSAT-2 data. Moreover, to evaluate the advantages and the different accuracy between the orientation models computed without GCPs and the orientation model with GCPs a Monte Carlo test was computed. At last, to define the real effectiveness of radargrammetric technique for DSM extraction and to compare the radrgrammetric tool implemented in a commercial software PCI-Geomatica v. 2012 and SISAR software, the images acquired on Beauport test site were used for DSM extraction. It is important underline that several test were computed. Part of this tests were carried out under the supervision of Prof. Thierry Toutin at CCRS (Canada Centre of Remote Sensing) where the PCI-Geomatica orientation model was developed, in order to check the better parameters solution to extract radargrammetric DSMs. In conclusion, the results obtained are representative of the geometric potentialities of SAR stereo pairs as regards 3D surface reconstruction

Grating-Coupled Surface Plasmon Resonance (GC-SPR) Optimization for Phase-Interrogation Biosensing in a Microfluidic Chamber.

Surface Plasmon Resonance (SPR)-based sensors have the advantage of being label-free, enzyme-free and real-time. However, their spreading in multidisciplinary research is still mostly limited to prism-coupled devices. Plasmonic gratings, combined with a simple and cost-effective instrumentation, have been poorly developed compared to prism-coupled system mainly due to their lower sensitivity. Here we describe the optimization and signal enhancement of a sensing platform based on phase-interrogation method, which entails the exploitation of a nanostructured sensor. This technique is particularly suitable for integration of the plasmonic sensor in a lab-on-a-chip platform and can be used in a microfluidic chamber to ease the sensing procedures and limit the injected volume. The careful optimization of most suitable experimental parameters by numerical simulations leads to a 30–50% enhancement of SPR response, opening new possibilities for applications in the biomedical research field while maintaining the ease and versatility of the configuration

Total angular momentum sorting in the telecom infrared with silicon Pancharatnam-Berry transformation optics

Parallel sorting of orbital angular momentum (OAM) and polarization has recently acquired paramount importance and interest in a wide range of fields ranging from telecommunications to high-dimensional quantum cryptography. Due to their inherently polarization-sensitive optical response, optical elements acting on the geometric phase prove to be useful for processing structured light beams with orthogonal polarization states by means of a single optical platform. In this work, we present the design, fabrication and test of a Pancharatnam-Berry optical element in silicon implementing a log-pol optical transformation at 1310 nm for the realization of an OAM sorter based on the conformal mapping between angular and linear momentum states. The metasurface is realized in the form of continuously-variant subwavelength gratings, providing high-resolution in the definition of the phase pattern. A hybrid device is fabricated assembling the metasurface for the geometric phase control with multi-level diffractive optics for the polarization-independent manipulation of the dynamic phase. The optical characterization confirms the capability to sort orbital angular momentum and circular polarization at the same time.Comment: 15 pages, 10 figure

Assessing the benefits of supply chain trust: NK simulation-based methodology and application

Previous literature has emphasized that developing trust among supply chain (SC) firms is a critical element in achieving SC effectiveness. Since developing trust is an expensive task, however, making an informed decision whether to invest or not in trust requires careful assessment of trust benefits. Therefore, we advance a simulation-based methodology to quantify performance improvements associated with trust in SCs. We develop an NK simulation model of a generic SC that captures the SC dynamics under two alternative scenarios, characterized by the presence and absence of trust respectively. A procedure is then illustrated to quantify the benefits of trust in the SC. We also apply our proposed methodology to a real-world SC. Results show that, when trust is pervasive across the SC, performance increases at both the levels of the overall SC and its leading firm