Sound Static Deadlock Analysis for C/Pthreads (Extended Version)

We present a static deadlock analysis approach for C/pthreads. The design of our method has been guided by the requirement to analyse real-world code. Our approach is sound (i.e., misses no deadlocks) for programs that have defined behaviour according to the C standard, and precise enough to prove deadlock-freedom for a large number of programs. The method consists of a pipeline of several analyses that build on a new context- and thread-sensitive abstract interpretation framework. We further present a lightweight dependency analysis to identify statements relevant to deadlock analysis and thus speed up the overall analysis. In our experimental evaluation, we succeeded to prove deadlock-freedom for 262 programs from the Debian GNU/Linux distribution with in total 2.6 MLOC in less than 11 hours

Endodontic therapy in one session versus two sessions

El objetivo principal de la endodoncia el a eliminación de tejido pulpar y microorganismos dentro del sistema de conductos radiculares por medio de una preparación químico- mecánica y su posterior obturación que consiste en el sellado hermético del mismo para evitar su reinfección. Actualmente, se discute ampliamente si los objetivos de la terapia endodóntica son alcanzables en una o en dos sesiones con medicación intraconducto donde el hidróxido de calcio es uno de los medicamentos intraconductos que más se utiliza y esto se debe a las excelentes propiedades que posee. Hoy en día, se postula que la verdadera causa de fracaso de muchos tratamientos de conductos aparentemente correctos es la entidad infecciosa conocida como biofilm. El objetivo de este trabajo fue comparar la evidencia radiográfica de la curación periapical después de un tratamiento de conducto realizado en una sola visita frente a dos visitas con una medicación intracanal con hidróxido de calcio.The main objective of endodontics is removing pulp tissue and microorganisms within the root canal system through a chemical mechanical preparation and subsequent sealing consisting hermetic sealing thereof to avoid reinfection. Currently, it is discussed whether the objectives of endodontic therapy are attainable in one or two sessions with intracanal medication where calcium hydroxide intraconductos is one of the most widely used drugs and this is due to the excellent properties it owns. Today, it is postulated that the true cause of failure of many treatments apparently correct conduit is infectious entity known as biofilm. The aim of this study was to compare the periapical radiographic evidence of healing after a root canal done in one visit versus two visits with intracanal medication with calcium hydroxide.Fil: Poetzl, María Paola. Universidad Nacional de Cuyo. Facultad de Odontologí

The North Platte River Valley: The Intersectionality between Water Quality and People

The North Platte River (NPR) Valley of western Nebraska is a semi-arid watershed with row crop production, livestock production, and urban land use activity and has a population of diverse stakeholders. These land use activities contribute to the enrichment of surface waters, such as streams, which can affect human and ecosystem health, as well as economic development and recreational activities. The project objectives are to: (1) quantify the movement of dissolved inorganic nutrients from the land within the NPR Valley to the NPR via tributaries and canals, (2) identify spatiotemporal variability of nutrient limitation of periphyton growth within the NPR, and (3) explore the factors that are associated with the adoption of a web-based water quality monitoring tool. To address the first two objectives, I collected water samples and discharge measurements from canals, tributaries (streams leading back into the NPR), and the NPR from the Wyoming–Nebraska border every three weeks from June–September 2021; and I performed repeated nutrient limitation bioassays every three weeks at nine sites. I found that land use within the NPR Valley contributes to nutrient enrichment of the NPR and the subsequent export of nutrients downstream. Based on the lack of response of periphyton to the nutrient bioassays, it is likely that the nutrients coming from the watershed meet periphyton growth demands, except, perhaps, during the end of the growing season when some nutrient limitation of growth was detected. To meet the third objective, I created a survey tool to understand how attitudes, norms, and beliefs (latent variables) affect the use of a web-based water quality monitoring tool. Performance expectancy was the only significant predictor of behavioral intention for water users to use a web-based water quality monitoring tool. From a management perspective, these studies emphasize the need for better management of nutrient exports from the NPR Valley, but the incorporation of functional goals into the deployment of potential water quality tools to ensure high behavioral intention to use the tool. Advisor: Jessica Corma

Internationalizing U.S. Master’s Universities: Emerging Opportunities for Marketing Faculty

One of the faster growing sectors of higher education in the US over the past three decades has been the master’s university. Another fundamental trend over this period has been the consistent increase in expectations of students, parents and business employers that international experiences and competencies become part of the curriculum at the undergraduate level. Opportunities for marketing faculty from master’s universities to add international perspectives to marketing courses have expanded over the past decade. The growth and re-shaping of faculty grant programs such as the Rockefeller, Rotary and Fulbright grants reflect this opportunity. In particular, the U.S. Fulbright Commission and the bi-national Fulbright commissions have enhanced international opportunities for master’s university faculty, making them flexible and, thereby more accessible to faculty at institutions with significant teaching loads. In the last decade, traditional student scholarship programs as well as newer programs like the Gilman Scholarship, have focused on increasing international study among minority students, both on the part of traditional student international scholarship funders as well as the Gilman Scholarship program. Regional master’s institutions typically serve more diverse student bodies. Taken together, these trends argue for a review of the opportunities for internationalization in regional master’s campuses across the US. The increasing global mobility required of business graduates, the critical role of faculty in guiding students toward greater intercultural competence, and the development of more flexible grants, offers marketing faculty seeking to deepen the international focus of their courses a more powerful way forward. This paper reviews data supporting these trends—and examines the types of grants now offered by the German Fulbright Commission as an example of this expanding interest in flexibility, master’s level universities, and minority students

Sound static deadlock analysis for C/Pthreads

We present a static deadlock analysis for C/Pthreads. The design of our method has been guided by the requirement to analyse real-world code. Our approach is sound (i.e., misses no deadlocks) for programs that have defined behaviour according to the C standard and the Pthreads specification, and is precise enough to prove deadlock-freedom for a large number of such programs. The method consists of a pipeline of several analyses that build on a new contextand thread-sensitive abstract interpretation framework. We further present a lightweight dependency analysis to identify statements relevant to deadlock analysis and thus speed up the overall analysis. In our experimental evaluation, we succeeded to prove deadlock-freedom for 292 programs from the Debian GNU/Linux distribution with in total 2.3 MLOC in 4 hours

BAMBI -A transient 2D-MESFET model with general boundary conditions including Schottky and current controlled contacts

Boundary conditions using a current-dependent carrier recombination velocity distribution are developed for modelling Schottky contacts by computer-aided physical simulation. In addition, a boundary condition in the form of an abitrary linear combination of voltage and current at the contact is presented. Thus MESFET devices with simple circuits connected to device terminals can be simulated by solving additional equations. As an example the switching behaviour of a MESFET with a drain resistor is investigated

Compositional Verification of Compiler Optimisations on Relaxed Memory

This paper is about verifying program transformations on an axiomatic relaxed memory model of the kind used in C/C++ and Java. Relaxed models present particular challenges for verifying program transformations, because they generate many additional modes of interaction between code and context. For a block of code being transformed, we define a denotation from its behaviour in a set of representative contexts. Our denotation summarises interactions of the code block with the rest of the program both through local and global variables, and through subtle synchronisation effects due to relaxed memory. We can then prove that a transformation does not introduce new program behaviours by comparing the denotations of the code block before and after. Our approach is compositional: by examining only representative contexts, transformations are verified for any context. It is also fully abstract, meaning any valid transformation can be verified. We cover several tricky aspects of C/C++-style memory models, including release-acquire operations, sequentially consistent fences, and non-atomics. We also define a variant of our denotation that is finite at the cost of losing full abstraction. Based on this variant, we have implemented a prototype verification tool and ap

Constraints on black-hole charges with the 2017 EHT observations of M87*

Our understanding of strong gravity near supermassive compact objects has recently improved thanks to the measurements made by the Event Horizon Telescope (EHT). We use here the M87* shadow size to infer constraints on the physical charges of a large variety of nonrotating or rotating black holes. For example, we show that the quality of the measurements is already sufficient to rule out that M87* is a highly charged dilaton black hole. Similarly, when considering black holes with two physical and independent charges, we are able to exclude considerable regions of the space of parameters for the doubly-charged dilaton and the Sen black holes

First M87 Event Horizon Telescope Results. VII. Polarization of the Ring

In 2017 April, the Event Horizon Telescope (EHT) observed the near-horizon region around the supermassive black hole at the core of the M87 galaxy. These 1.3 mm wavelength observations revealed a compact asymmetric ring-like source morphology. This structure originates from synchrotron emission produced by relativistic plasma located in the immediate vicinity of the black hole. Here we present the corresponding linear-polarimetric EHT images of the center of M87. We find that only a part of the ring is significantly polarized. The resolved fractional linear polarization has a maximum located in the southwest part of the ring, where it rises to the level of ~15%. The polarization position angles are arranged in a nearly azimuthal pattern. We perform quantitative measurements of relevant polarimetric properties of the compact emission and find evidence for the temporal evolution of the polarized source structure over one week of EHT observations. The details of the polarimetric data reduction and calibration methodology are provided. We carry out the data analysis using multiple independent imaging and modeling techniques, each of which is validated against a suite of synthetic data sets. The gross polarimetric structure and its apparent evolution with time are insensitive to the method used to reconstruct the image. These polarimetric images carry information about the structure of the magnetic fields responsible for the synchrotron emission. Their physical interpretation is discussed in an accompanying publication