Computer aided design and finite element modeling to predict bulk mechanical properties of bone scaffolds using triply periodic minimal surfaces (progettazione assistita al calcolatore ed analisi con il metodo degli elementi finiti per predire il comportamento meccanico di scaffolds ossei creati con l'uso di superfici minime periodiche in tre direzioni)

The aim of Tissue Engineering is to develop biological substitutes that will restore lost morphological and functional features of diseased or damaged portions of organs. Recently computer-aided technology has received considerable attention in the area of tissue engineering and the advance of additive manufacture (AM) techniques has significantly improved control over the pore network architecture of tissue engineering scaffolds. To regenerate tissues more efficiently, an ideal scaffold should have appropriate porosity and pore structure. More sophisticated porous configurations with higher architectures of the pore network and scaffolding structures that mimic the intricate architecture and complexity of native organs and tissues are then required. This study adopts a macro-structural shape design approach to the production of open porous materials (Titanium foams), which utilizes spatial periodicity as a simple way to generate the models. From among various pore architectures which have been studied, this work simulated pore structure by triply-periodic minimal surfaces (TPMS) for the construction of tissue engineering scaffolds. TPMS are shown to be a versatile source of biomorphic scaffold design. A set of tissue scaffolds using the TPMS-based unit cell libraries was designed. TPMS-based Titanium foams were meant to be printed three dimensional with the relative predicted geometry, microstructure and consequently mechanical properties. Trough a finite element analysis (FEA) the mechanical properties of the designed scaffolds were determined in compression and analyzed in terms of their porosity and assemblies of unit cells. The purpose of this work was to investigate the mechanical performance of TPMS models trying to understand the best compromise between mechanical and geometrical requirements of the scaffolds. The intention was to predict the structural modulus in open porous materials via structural design of interconnected three-dimensional lattices, hence optimising geometrical properties. With the aid of FEA results, it is expected that the effective mechanical properties for the TPMS-based scaffold units can be used to design optimized scaffolds for tissue engineering applications. Regardless of the influence of fabrication method, it is desirable to calculate scaffold properties so that the effect of these properties on tissue regeneration may be better understood.

Interacting bosons and fermions in three-dimensional optical lattice potentials

This thesis reports on the realization, characterization and analysis of ultracold bosonic and fermionic atoms in three-dimensional optical lattice potentials. Ultracold quantum gases in optical lattices can be regarded as ideal model systems to investigate quantum many-body physics. In this work interacting ensembles of bosonic 87Rb and fermionic 40K atoms are employed to study equilibrium phases and nonequilibrium dynamics. The investigations are enabled by a versatile experimental setup, whose core feature is a blue-detuned optical lattice that is combined with Feshbach resonances and a red-detuned dipole trap to allow for independent control of tunneling, interactions and external confinement. The Fermi-Hubbard model, which plays a central role in the theoretical description of strongly correlated electrons, is experimentally realized by loading interacting fermionic spin mixtures into the optical lattice. Using phase-contrast imaging the in-situ size of the atomic density distribution is measured, which allows to extract the global compressibility of the many-body state as a function of interaction and external confinement. Thereby, metallic and insulating phases are clearly identified. At strongly repulsive interaction, a vanishing compressibility and suppression of doubly occupied lattice sites signal the emergence of a fermionic Mott insulator. In a second series of experiments interaction effects in bosonic lattice quantum gases are analyzed. Typically, interactions between microscopic particles are described as two-body interactions. As such they are also contained in the single-band Bose-Hubbard model. However, our measurements demonstrate the presence of multi-body interactions that effectively emerge via virtual transitions of atoms to higher lattice bands. These findings are enabled by the development of a novel atom optical measurement technique: In quantum phase revival spectroscopy periodic collapse and revival dynamics of the bosonic matter wave field are induced. The frequencies of the dynamics are directly related to the on-site interaction energies of atomic Fock states and can be read out with high precision. The third part of this work deals with mixtures of bosons and fermions in optical lattices, in which the interspecies interactions are accurately controlled by means of a Feshbach resonance. Studies of the equilibrium phases show that the bosonic superfluid to Mott insulator transition is shifted towards lower lattice depths when bosons and fermions interact attractively. This observation is further analyzed by applying quantum phase revival spectroscopy to few-body systems consisting of a single fermion and a coherent bosonic field on individual lattice sites. In addition to the direct measurement of Bose-Fermi interaction energies, Bose-Bose interactions are proven to be modified by the presence of a fermion. This renormalization of bosonic interaction energies can explain the shift of the Mott insulator transition. The experiments of this thesis lay important foundations for future studies of quantum magnetism with fermionic spin mixtures as well as for the realization of complex quantum phases with Bose-Fermi mixtures. They furthermore point towards physics that reaches beyond the single-band Hubbard model.

Computer simulation studies of vector spin glasses

Die vorliegende Doktorarbeit befasst sich mit klassischen Vektor-Spingläsern eine Art von ungeordneten Magneten - auf verschiedenen Gittertypen. Da siernbedeutsam für eine experimentelle Realisierung sind, ist ein theoretisches Verständnis von Spinglas-Modellen mit wenigen Spinkomponenten und niedriger Gitterdimension von großer Bedeutung. Da sich dies jedoch als sehr schwierigrnerweist, sind neue, aussichtsreiche Ansätze nötig. Diese Arbeit betrachtet daher den Limesrnunendlich vieler Spindimensionen. Darin entstehen mehrere Vereinfachungen im Vergleichrnzu Modellen niedriger Spindimension, so dass für dieses bedeutsame Problem Eigenschaften sowohl bei Temperatur Null als auch bei endlichen Temperaturenrnüberwiegend mit numerischen Methoden ermittelt werden. Sowohl hyperkubische Gitter als auch ein vielseitiges 1d-Modell werden betrachtet. Letzteres erlaubt es, unterschiedliche Universalitätsklassen durch bloßes Abstimmen eines einzigen Parameters zu untersuchen. "Finite-size scaling''-Formen, kritische Exponenten, Quotienten kritischer Exponenten und andere kritische Größen werden nahegelegt und mit numerischen Ergebnissen verglichen. Eine detaillierte Beschreibung der Herleitungen aller numerisch ausgewerteter Gleichungen wird ebenso angegeben. Bei Temperatur Null wird eine gründliche Untersuchung der Grundzustände und Defektenergien gemacht. Eine Reihe interessanter Größen wird analysiert und insbesondere die untere kritische Dimension bestimmt. Bei endlicher Temperatur sind der Ordnungsparameter und die Spinglas-Suszeptibilität über die numerisch berechnete Korrelationsmatrix zugänglich. Das Spinglas-Modell im Limes unendlich vieler Spinkomponenten kann man als Ausgangspunkt zur Untersuchung der natürlicheren Modelle mit niedriger Spindimension betrachten. Wünschenswert wäre natürlich ein Modell, das die Vorteile des ersten mit den Eigenschaften des zweiten verbände. Daher wird in Modell mit Anisotropie vorgeschlagen und getestet, mit welchem versucht wird, dieses Ziel zu erreichen. Es wird auf reizvolle Wege hingewiesen, das Modell zu nutzen und eine tiefergehende Beschäftigung anzuregen. Zuletzt werden sogenannte "real-space" Renormierungsgruppenrechnungen sowohl analytisch als auch numerisch für endlich-dimensionale Vektor-Spingläser mit endlicher Anzahl von Spinkomponenten durchgeführt. Dies wird mit einer zuvor bestimmten neuen Migdal-Kadanoff Rekursionsrelation geschehen. Neben anderen Größen wird die untere kritische Dimension bestimmt.

La rappresentazione cinematografica del mondo agropastorale nel documentario corto italiano (1939 - 1969)

L’obiettivo primario di questo lavoro è quello di esplorare un insieme di documentari corti italiani di tipo etnografico e sociologico. Questi film hanno ricevuto pochissima attenzione critica, mentre sono essenziali alla comprensione del periodo di storia italiana compreso fra gli ultimi anni del Regime fascista e la fine del “Miracolo economico”. La prima parte della tesi è dedicata alla descrizione del contesto economico, sociologico, politico in cui questi lavori sono stati prodotti. La seconda parte si concentra su circa un centinaio di documentari corti analizzati sulla base di tre diversi criteri. Innanzitutto li abbiamo considerati a partire da un punto di vista autoriale, secondariamente a partire dalle loro caratteristiche produttive e distributive e infine sulla base di un criterio regionale. A partire dalla discussione antropologica coeva riguardante la scomparsa dei mondi contadini e su una precisa ricerca d’archivio focalizzata sullo stesso tema, abbiamo poi comparato il risultato dell’analisi del corpus con altre forme filmiche di rappresentazione dello stesso soggetto. Oltre a far riemergere un gruppo di autori e film quasi dimenticati, questo lavoro intende lanciare uno sguardo sul veloce, conflittuale e sbilanciato cambiamento compreso fra i mondi rurali tradizionali e la modernità, che ha caratterizzato la società italiana degli anni Cinquanta e Sessanta.

Groups Acting on Tensor Products

Groups preserving a distributive product are encountered often in algebra. Examples include automorphism groups of associative and nonassociative rings, classical groups, and automorphism groups of p-groups. While the great variety of such products precludes any realistic hope of describing the general structure of the groups that preserve them, it is reasonable to expect that insight may be gained from an examination of the universal distributive products: tensor products. We give a detailed description of the groups preserving tensor products over semisimple and semiprimary rings, and present effective algorithms to construct generators for these groups. We also discuss applications of our methods to algorithmic problems for which all currently known methods require an exponential amount of work. (C) 2013 Elsevier B.V. All rights reserved.

Health, Justice, and Fairness

In this study I will endeavor to show that the American system of health care violates any conception of distributive justice understood as equality of opportunity. This system fails to provide equal access through a lack of universal insurance, a consumer driven conception of quality, and a system wide focus on cost control, leaving millions of Americans exposed to the ravages of disease. However, if health is understood as an antecedent for one's ability to function across a number of categories that have been objectively deemed as vital to engage in a life that is fully human than the commitment our nation has to the protection of fair equality of opportunity, established by our adoption of a Rawlsian conception of justice, necessitates a revision of our nation's conception of quality to encapsulate health outcomes as well as the advent of a system of universal coverage. Quality care will come to be understood as care that returns to the patient the ability to function across those categories of functioning that illness has jeopardized, and this conception of quality will precipitate system wide reform geared at the creation of positive health outcomes. This paper will articulate this argument by reconstructing and synthesizing precepts from the contemporary philosophical sources and then applying these to the practical workings of our healthcare system, while concurrently demonstrating that a system of distributive justice is compatible with the creation of a universal system of healthcare.

A Study of the Diffusion of Electroplated Coatings in the Solid State.

The term diffusion means an equalization or homogenization of diverse materials. Specifically ap­plied to metals, diffusion is the interchange of atoms. It is, in effect, an invasion of one crystal lattice by the atoms of one or more other crystal lattices. Therefore, the study of diffusion must involve the geometry and physics of crystal lattices as well as their energies.

Amalgamation and interpolation in ordered algebras

The first part of this paper provides a comprehensive and self-contained account of the interrelationships between algebraic properties of varieties and properties of their free algebras and equational consequence relations. In particular, proofs are given of known equivalences between the amalgamation property and the Robinson property, the congruence extension property and the extension property, and the flat amalgamation property and the deductive interpolation property, as well as various dependencies between these properties. These relationships are then exploited in the second part of the paper in order to provide new proofs of amalgamation and deductive interpolation for the varieties of lattice-ordered abelian groups and MV-algebras, and to determine important subvarieties of residuated lattices where these properties hold or fail. In particular, a full description is given of all subvarieties of commutative GMV-algebras possessing the amalgamation property.

Atomic Quantum Simulation of U(N) and SU(N) Abelian Lattice Gauge Theories

Using ultracold alkaline-earth atoms in optical lattices, we construct a quantum simulator for U(N) and SU(N) lattice gauge theories with fermionic matter based on quantum link models. These systems share qualitative features with QCD, including chiral symmetry breaking and restoration at nonzero temperature or baryon density. Unlike classical simulations, a quantum simulator does not suffer from sign problems and can address the corresponding chiral dynamics in real time.

Ultracold Quantum Gases and Lattice Systems: Quantum Simulation of Lattice Gauge Theories

Abelian and non-Abelian gauge theories are of central importance in many areas of physics. In condensed matter physics, AbelianU(1) lattice gauge theories arise in the description of certain quantum spin liquids. In quantum information theory, Kitaev’s toric code is a Z(2) lattice gauge theory. In particle physics, Quantum Chromodynamics (QCD), the non-Abelian SU(3) gauge theory of the strong interactions between quarks and gluons, is nonperturbatively regularized on a lattice. Quantum link models extend the concept of lattice gauge theories beyond the Wilson formulation, and are well suited for both digital and analog quantum simulation using ultracold atomic gases in optical lattices. Since quantum simulators do not suffer from the notorious sign problem, they open the door to studies of the real-time evolution of strongly coupled quantum systems, which are impossible with classical simulation methods. A plethora of interesting lattice gauge theories suggests itself for quantum simulation, which should allow us to address very challenging problems, ranging from confinement and deconfinement, or chiral symmetry breaking and its restoration at finite baryon density, to color superconductivity and the real-time evolution of heavy-ion collisions, first in simpler model gauge theories and ultimately in QCD.

Synchrotron microbeam radiation therapy induces hypoxia in intracerebral gliosarcoma but not in the normal brain

PURPOSE Synchrotron microbeam radiation therapy (MRT) is an innovative irradiation modality based on spatial fractionation of a high-dose X-ray beam into lattices of microbeams. The increase in lifespan of brain tumor-bearing rats is associated with vascular damage but the physiological consequences of MRT on blood vessels have not been described. In this manuscript, we evaluate the oxygenation changes induced by MRT in an intracerebral 9L gliosarcoma model. METHODS Tissue responses to MRT (two orthogonal arrays (2 × 400Gy)) were studied using magnetic resonance-based measurements of local blood oxygen saturation (MR_SO2) and quantitative immunohistology of RECA-1, Type-IV collagen and GLUT-1, marker of hypoxia. RESULTS In tumors, MR_SO2 decreased by a factor of 2 in tumor between day 8 and day 45 after MRT. This correlated with tumor vascular remodeling, i.e. decrease in vessel density, increases in half-vessel distances (×5) and GLUT-1 immunoreactivity. Conversely, MRT did not change normal brain MR_SO2, although vessel inter-distances increased slightly. CONCLUSION We provide new evidence for the differential effect of MRT on tumor vasculature, an effect that leads to tumor hypoxia. As hypothesized formerly, the vasculature of the normal brain exposed to MRT remains sufficiently perfused to prevent any hypoxia.

One size fits all? Managing trust and privacy on social networking sites in Russia and Germany

When it comes to platform sustainability, mitigating user privacy concerns and enhancing trust represent two major tasks providers of Social Networking Sites (SNSs) are facing today. State-of-the-art research advocates reliance on the justice-based measures as possible means to address these challenges. However, as providers are increasingly expanding into foreign markets, the effectiveness of these measures in a cross-cultural setting is questioned. In an attempt to address this set of issues, in this study we build on the existing model to examine the impact of culture on the robustness of four justice-based means in mitigating privacy concerns and ensuring trust. Survey responses from German and Russian SNS members are used to evaluate the two structural equation models, which are then compared. We find that perceptions regarding Procedural and Informational Justice are universally important and hence should be addressed as part of the basic strategy by the SNS provider. When expanding to collectivistic countries like Russia, measures enhancing perceptions of Distributive and Interpersonal Justice can be additionally applied. Beyond practical implications, our study makes a significant contribution to the theoretical discourse on the role of culture in determining individual perceptions and behavior.

Illegitimate Tasks: Accumulating Evidence for a New Stressor Concept

INTRODUCTION: Task stressors typically refer to characteristics such as not having enough time or resources, ambiguous demands, or the like. We suggest the perceived lack of legitimacy as an additional feature of tasks as a source of stress. Tasks are “illegitimate” to the extent that it is perceived as improper to expect employees to execute them – not because of difficulties in executing them, but because of their content for a given person, time, and situation; they are illegitimate because a) they are not conforming to a specific occupational role, as in “non-nursing activities” (called unreasonable) or b) there is no legitimate need for them to exist (called unnecessary; Semmer et al., 2007). These features make illegitimate tasks a unique task-related stressor. The concept of illegitimate tasks grew from the “Stress-as-Offense-to-Self” theory (SOS; Semmer et al, 2007); it is conceptually related to role stress (Kahn et al., 1964; Beehr & Glazer, 2005) and the organizational justice tradition (Cropanzano et al., 2001; Greenberg, 2010). SOS argues that a threat to one’s self-image is at the core of many stressful experiences. Violating role expectations, illegitimate tasks can be regarded as a special case of role conflict. As roles shape identities, this violation is postulated to constitute a threat to one’s professional identity. Being assigned a task considered illegitimate is likely to be considered unfair. Lack of fairness, in turn, contains a message about one’s social standing, and thus, the self. However, the aspects discussed have not received much attention in the role stress or the justice/fairness tradition. OBJECTIVE: Illegitimate tasks are a rather recent concept that has to be established as a construct in its own right by showing that it is associated with well-being/strain while controlling for other stressors, most notably role conflict and lack of justice. The aim of the presentation is to present the evidence accumulated so far. METHODS AND RESULTS: We present several studies employing different designs, using different control variables, and testing associations with different criteria. Study 1 demonstrates associations of illegitimate tasks with self-esteem, feelings of resentment against one’s organization, and burnout, controlling for distributive justice, role conflict, and social stressors (i.e. tensions). Study 2 yielded comparable results, using the same outcome variables but controlling for distributive as well as procedural / interactional justice. Study 3 demonstrated associations between illegitimate tasks and feelings of stress, sleeping problems, and emotional exhaustion, controlling for demands, control, and social support among medical doctors. Study 4 showed that feeling appreciated by one’s superior acted as a mediator between illegitimate tasks and job satisfaction and resentments towards the military in Swiss military officers. Study 5 demonstrated an association of illegitimate tasks with counterproductive work behavior (Semmer et al. 2010). Studies 1 to 5 were cross-sectional. In Study 6, illegitimate demands predicted irritability and resentments towards one’s organization longitudinally. Study 7 also was longitudinal, focusing on intra-individual variation in multilevel modeling; occasion-specific illegitimate tasks predicted cortisol among those who judged their health as comparatively poor. Studies 1-3 and 6 used SEM, and measurement models that used unreasonable and unnecessary tasks as indicators (isolated parceling) yielded a good fit. IMPLICATIONS & CONCLUSIONS: These studies demonstrate that illegitimate tasks are a stressor in its own right that is worth studying. It illuminates the social meaning of job design, emphasizing the implications of tasks for the (professional) self, and thus combining aspects that are traditionally treated as separate, that is, social aspects and task characteristics. Practical implications are that supervisors and managers should be alerted to the social messages that may be contained in task assignments (cf. Semmer & Beehr, in press).

The evolution and assessment of pharmaceutical care: Structure, processes, and outcomes

The evolution of pharmaceutical care is identified through a complete review of the literature published in the American Journal of Health-System Pharmacy, the sole comprehensive publication of institutional pharmacy practice. The evolution is categorized according to characteristics of structure (organizational structure, the role of the pharmacist), process (drug delivery systems, formulary management, acquiring drug products, methods to impact drug therapy decisions), and outcomes (cost of drug delivery, cost of drug acquisition and use, improved safety, improved health outcomes) recorded from the 1950s through the 1990s. While significant progress has been made in implementing basic drug distribution systems, levels of pharmacy involvement with direct patient care is still limited.^ A new practice framework suggests enhanced direct patient care involvement through increase in the efficiency and effectiveness of traditional pharmacy services. Recommendations advance internal and external organizational structure relationships that position pharmacists to fully use their unique skills and knowledge to impact drug therapy decisions and outcomes. Specific strategies facilitate expansion of the breadth and scope of each process component in order to expand the depth of integration of pharmacy and pharmaceutical care within the broad healthcare environment. Economic evaluation methods formally evaluate the impact of both operational and clinical interventions.^ Outcome measurements include specific recommendations and methods to increase efficiency of drug acquisition, emphasizing pharmacists' roles that impact physician prescribing decisions. Effectiveness measures include those that improve safety of drug distribution systems, decrease the potential of adverse drug therapy events, and demonstrate that pharmaceutical care can significantly contribute to improvement in overall health status.^ The implementation of the new framework is modeled on a case study at the M.D. Anderson Cancer Center. The implementation of several new drug distribution methods facilitated the redeployment of personnel from distributive functions to direct patient care activities with significant personnel and drug cost reduction. A cost-benefit analysis illustrates that framework process enhancements produced a benefit-to-cost ratio of 7.9. In addition, measures of effectiveness demonstrated significant levels of safety and enhanced drug therapy outcomes. ^

Two-dimensional Lattice Gauge Theories with Superconducting Quantum Circuits

A quantum simulator of U(1) lattice gauge theories can be implemented with superconducting circuits. This allows the investigation of confined and deconfined phases in quantum link models, and of valence bond solid and spin liquid phases in quantum dimer models. Fractionalized confining strings and the real-time dynamics of quantum phase transitions are accessible as well. Here we show how state-of-the-art superconducting technology allows us to simulate these phenomena in relatively small circuit lattices. By exploiting the strong non-linear couplings between quantized excitations emerging when superconducting qubits are coupled, we show how to engineer gauge invariant Hamiltonians, including ring-exchange and four-body Ising interactions. We demonstrate that, despite decoherence and disorder effects, minimal circuit instances allow us to investigate properties such as the dynamics of electric flux strings, signaling confinement in gauge invariant field theories. The experimental realization of these models in larger superconducting circuits could address open questions beyond current computational capability.