The Max-Min Principle of Product Differentiation: An Experimental Analysis

Theoretical models of multidimensional product differentiation predict that in duopoly firms differentiate maximally along one dimension and minimally along the other dimensions. We experimentally reproduce a market in which firms can differentiate their products along two horizontal dimensions. The main result is that subjects do not differentiate their products and locate near the center consumers' distribution.-

The Predictive Power of Zero Intelligence in Financial Markets

Standard models in economics stress the role of intelligent agents who maximize utility. However, there may be situations where, for some purposes, constraints imposed by market institutions dominate intelligent agent behavior. We use data from the London Stock Exchange to test a simple model in which zero intelligence agents place orders to trade at random. The model treats the statistical mechanics of order placement, price formation, and the accumulation of revealed supply and demand within the context of the continuous double auction, and yields simple laws relating order arrival rates to statistical properties of the market. We test the validity of these laws in explaining the cross-sectional variation for eleven stocks. The model explains 96% of the variance of the bid-ask spread, and 76% of the variance of the price diffusion rate, with only one free parameter. We also study the market impact function, describing the response of quoted prices to the arrival of new orders. The non-dimensional coordinates dictated by the model approximately collapse data from different stocks onto a single curve. This work is important from a practical point of view because it demonstrates the existence of simple laws relating prices to order flows, and in a broader context, because it suggests that there are circumstances where institutions are more important than strategic considerations

M10: Friction Atlas: A Choreographed Debate About Public Space, Law and Legibility

Projekt moderniteta nastoji učiniti svijet – a naposljetku i njegovo stanovništvo – „čitljivim“. Prema mišljenju Jamesa C. Scotta, institucije i organizacije filtriraju one podatke koje trebaju znati kako bi ih apstrahirale, ujednačile i podastrle na način koji će ih učiniti čitljivima; a zatim će se svijet preoblikovati po uzoru na tu apstrakciju.1 Navikavamo se na to da se ponašanje građana – korisnika, klijenata, potrošača – predstavlja mapiranjem u stvarnom vremenu i vizualizacijom podataka, što pak sve više oblikuje ono što ljudi vide i mogu učiniti. S druge strane, Kevin Lynch koristi pojam „čitljivost“ kako bi označio percepcijsku jasnoću urbanog okoliša ili „lakoću s kojom njegovi stanovnici mogu prepoznati njegove dijelove“.2 Iskustvo urbanog okoliša, kao i mentalna karta koja iz njega proizlazi, čine sustave čitljivijima razotkrivajući njihovu strukturu i aktivnost. Mentalne karte dopuštaju građanima određeni stupanj djelotvornosti tako što utječu na opseg mogućih interakcija: kada ih se operacionalizira, one omogućuju reprogramiranje, hakiranje i dekonstrukciju. U našem urbanom iskustvu zakon je nevidljiv, no uvijek implicitno prisutan. Regulacije o uporabi javnog prostora – simboli, konvencije – imaju moć da uvjere ljude u nužnost djelovanja. To su skupovi uputa koji utjelovljuju moć kao nevidljivu strukturalnu silu koja se očituje u svakodnevnom životu kao sinkronizirana rutina razrađenih kretanja javnim površinama, neka vrsta koreografije. U tom kontekstu „Atlas trenja“ je kritička intervencija koja koristi grafička sredstva i izvedbene prakse kako bi preoblikovala lokalne zakone u sasvim vidljive aktere, nudeći moguće modele za otvaranje prema novim oblicima građanskog i estetskog bavljenja skrivenim ili apstraktnim slojevima grada.The modern project aims at making the world – and ultimately its population – “legible”. According to James C. Scott, institutions and organisations filter the type of data they need to know, in order to abstract, flatten and spread it out in a way that makes it readable; then, it is the world that is reformed in the image of that abstraction.1 We are getting accustomed to seeing the behaviour of citizens – users, customers, consumers – represented through real-time maps and data visualisations, which in turn increasingly inform what people see and can do. On the other hand, the term “legibility” is used by Kevin Lynch to signify the perceptual clarity of an urban environment, or “the ease with which its parts can be recognised by its inhabitants”.2 The experience of the urban environment, and the resulting mental map, make systems more legible, by exposing their structure and activity. Mental maps grant citizens a degree of agency, affecting the range of possible interactions: when operationalised they enable reprogramming, hacking, and deconstructing. In our urban experience, law is invisible, but always implicitly present. Regulations on the use of public space – symbols, conventions – have the power of persuading human beings to act. They are sets of instructions that incorporate power, an invisible structural force that plays through into everyday life, in a synchronised routine of elaborate moves on public surfaces, a choreography. In this context, Friction Atlas is a critical intervention that through graphical devices and performative practices reshape local laws into fully visible agents, providing possible models for opening up to new forms of civic and aesthetic engagement with hidden or abstract layers of the city

Nanoroughness, Surface Chemistry and Drug Delivery Control by Atmospheric Plasma Jet on Implantable Devices

Implantable devices need specific tailored surface morphologies and chemistries to interact with the living systems or to actively induce a biological response also by the release of drugs or proteins. These customised requirements foster technologies that can be implemented in additive manufacturing systems. Here we present a novel approach based on spraying processes that allows to control separately topographic features in the submicron range ( 3d 60 nm - 2 \ub5m), ammine or carboxylic chemistry and fluorophore release even on temperature sensitive biodegradable polymers such as polycaprolactone (PCL). We developed a two-steps process with a first deposition of 220 nm silica and poly(lactic-co-glycolide) (PLGA) fluorescent nanoparticles by aerosol followed by the deposition of a fixing layer by atmospheric pressure plasma jet (APPJ). The nanoparticles can be used to create the nano-roughness and to include active molecule release, while the capping layer ensures stability and the chemical functionalities. The process is enabled by a novel APPJ which allows deposition rates of 10 - 20 nm\ub7s-1 at temperatures lower than 50 \ub0C using argon as process gas. This approach was assessed on titanium alloys for dental implants and on PCL films. The surfaces were characterized by FT-IR, AFM and SEM. Titanium alloys were tested with pre-osteoblasts murine cells line, while PCL film with fibroblasts. Cell behaviour was evaluated by viability and adhesion assays, protein adsorption, cell proliferation, focal adhesion formation and SEM. The release of a fluorophore molecule was assessed in the cell growing media, simulating a drug release. Osteoblast adhesion on the plasma treated materials increased by 20% with respect to commercial titanium alloys implants. Fibroblast adhesion increased by a 100% compared to smooth PCL substrate. The release of the fluorophore by the dissolution of the PLGA nanoparticles was verified and the integrity of the encapsulated drug model confirmed

Influence of the substrate temperature on the layer properties made by an atmospheric plasma jet using different precursors

In this work the surface temperature of porous polymer scaffolds treated with an atmospheric plasma jet was determined by theoretical estimations and infrared was measurements. Based on these results the scaffolds were coated with functional plasma polymer layers using this plasma jet and different precursors. The influence of the substrate temperature on the plasma polymer layer properties like thickness and chemical reactivity was investigated

A novel plasma jet with RF and HF coupled electrodes

In order to achieve low processing temperature and efficient coatings deposition for manufacturing applications, a novel torch has been developed that couples in a double DBD design high frequency (HF ~17 kHz) and radio frequency (RF ~27 MHz) excitations. The design allows to obtain a stable RF plasma also in reactive processes and with the possibility to control on the treated substrates ions flux and surface charging, avoiding the micro-discharges. The plasma has been electrically and optically characterized by emission spectroscopy

Damage assessment of bridge piers subjected to multiple earthquakes : Markov model vs regression models

Recently developed methodologies based on a probabilistic seismic demand model (PSDM) and based on a Markovian model for the prediction of damage accumulation in structures subjected to multiple earthquakes within their lifetime are compared. A stochastic earthquake hazard model is used for generating sample sequences of ground motion records providing the reference solution and then used to estimate the probabilistic distribution of the damage accumulated during the time interval of interest. Besides evaluating the effectiveness of each approach, possible improvements of the cumulative demand model are tested. A reinforced concrete bridge model with a single pier is examined as case study and Park-Ang damage index is considered to describe the damage accumulation. The results demonstrate the importance of considering the occurrence of multiple shocks.Recently developed methodologies based on a probabilistic seismic demand model (PSDM) and based on a Markovian model for the prediction of damage accumulation in structures subjected to multiple earthquakes within their lifetime are compared. A stochastic earthquake hazard model is used for generating sample sequences of ground motion records providing the reference solution and then used to estimate the probabilistic distribution of the damage accumulated during the time interval of interest. Besides evaluating the effectiveness of each approach, possible improvements of the cumulative demand model are tested. A reinforced concrete bridge model with a single pier is examined as case study and Park-Ang damage index is considered to describe the damage accumulation. The results demonstrate the importance of considering the occurrence of multiple shocks

The “polonium in vivo” study. Polonium-210 in bronchial lavages of patients with suspected lung cancer

Few studies have reported on polonium-210, a decay breakdown product of radon-222 and lead-210, in human lungs and there has been no study in patients with suspected lung cancer. The main aim of this "Polonium in vivo" study was to evaluate polonium-210 radioactivity in bronchopulmonary systems of smoker, ex-smoker and never smoker patients with suspected lung cancer. Alpha-spectrometric analyses were performed on bronchial lavage (BL) fluids from two Italian hospitals in 2013-2016. Socio-demographic, smoking, occupational and spirometric characteristics, lung cancer confirmation and histologic type and radon-222 concentration in patients' homes were collected. Seventy BL samples from never (n = 13), former (n = 35) and current smokers (n = 22) were analyzed; polonium-210 was detected in all samples from current and former smokers and in 54% of samples from never smokers (p < 0.001; median values: 1.20, 1.43 and 0.40 mBq, respectively). Polonium-210 levels were significantly higher in COPD versus no COPD patients (median value: 3.60 vs. 0.97 mBq; p = 0.007); former and current smokers, without and with COPD, had significantly increased polonium-210 levels (p = 0.012); 96% of confirmed versus 69% of non-confirmed lung cancer patients recorded detectable polonium-210 levels (p = 0.018). A polonium-210 detectable activity was measured in BL samples from all current and former smokers. Polonium-210 in the lungs could be the result of lead-210 entrapment, which, with its half-life of 22 years, could provide a continuous emission of alpha radioactivity, even many years after quitting, thus proposing a possible explanation for the onset of lung cancer, particularly in former smokers

3D additive manufactured composite scaffolds with antibiotic-loaded lamellar fillers for bone infection prevention and tissue regeneration

Bone infections following open bone fracture or implant surgery remain a challenge in the orthopedics field. In order to avoid high doses of systemic drug administration, optimized local antibiotic release from scaffolds is required. 3D additive manufactured (AM) scaffolds made with biodegradable polymers are ideal to support bone healing in non-union scenarios and can be given antimicrobial properties by the incorporation of antibiotics. In this study, ciprofloxacin and gentamicin intercalated in the interlamellar spaces of magnesium aluminum layered double hydroxides (MgAl) and α-zirconium phosphates (ZrP), respectively, are dispersed within a thermoplastic polymer by melt compounding and subsequently processed via high temperature melt extrusion AM (~190 °C) into 3D scaffolds. The inorganic fillers enable a sustained antibiotics release through the polymer matrix, controlled by antibiotics counterions exchange or pH conditions. Importantly, both antibiotics retain their functionality after the manufacturing process at high temperatures, as verified by their activity against both Gram + and Gram - bacterial strains. Moreover, scaffolds loaded with filler-antibiotic do not impair human mesenchymal stromal cells osteogenic differentiation, allowing matrix mineralization and the expression of relevant osteogenic markers. Overall, these results suggest the possibility of fabricating dual functionality 3D scaffolds via high temperature melt extrusion for bone regeneration and infection prevention.We are grateful to the FAST project funded under the H2020-NMP- PILOTS-2015 scheme (GA n. 685825) for financial support. Some of the materials used in this work were provided by the Texas A&M Health Science Center College of Medicine Institute for Regenerative Medicine at Scott & White through a grant from NCRR of the NIH (Grant #P40RR017447)

Comparison of 5-year progression of retinitis pigmentosa involving the posterior pole among siblings by means of SD-OCT: a retrospective study

The blockchain technology promises to transform finance, money and evengovernments. However, analyses of blockchain applicability and robustness typicallyfocus on isolated systems whose actors contribute mainly by running the consensusalgorithm. Here, we highlight the importance of considering trustless platformswithin the broader ecosystem that includes social and communication networks. Asan example, we analyse the flash-crash observed on 21st June 2017 in the Ethereumplatform and show that a major phenomenon of social coordination led to acatastrophic cascade of events across several interconnected systems. We proposethe concept of “emergent centralisation” to describe situations where a single systembecomes critically important for the functioning of the whole ecosystem, and arguethat such situations are likely to become more and more frequent in interconnectedsocio-technical systems. We anticipate that the systemic approach we propose willhave implications for future assessments of trustless systems and call for the attentionof policy-makers on the fragility of our interconnected and rapidly changing world