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ABSTRACT Ankle injuries are the most common musculoskeletal injuries in emergency rooms and are associated with a great social and economic impact. The need to request additional tests for ankle sprains is based on suspicion of fracture. The Ottawa Ankle Rules (OAR) establish criteria for ordering radiographs to avoid performing unnecessary examinations. Objective: To evaluate the implementation of the Ottawa Rules as a protocol for treating ankle sprains in the emergency department of a university hospital. Methods: This is a retrospective observational study, conducted over a period of three months before and three months after implementation of the protocol. Results: In the first phase, all patients complaining of ankle sprain underwent radiographs. In the second phase, after the application of the OAR, out of 85 patients evaluated, only 58 underwent complementary exams, showing a reduction of 31.8% in the request for imaging exams. There was no significant difference in fracture detection between the two groups (p=0.476). Conclusion: The OAR can be used as a tool in diagnosing ankle sprains, and their implementation reduced the request for imaging exams. Level of Evidence III, Retrospective Comparative Study.

Background: Risk-factors for mortality in hip fractures encompass nutritional status, nominally body mass index, but not body composition. Given the difficulty of anthropometric assessment in bedridden patients a prospective study with bioimpedance analysis was designed. Methods: Elderly patients with hip fracture were consecutively recruited. Biochemical tests, primitive bioimpedance measurements (resistance, reactance and phase angle) and follow-up till one year were targeted. Results: Patients (N = 69, 81.2 ± 8.1 years old, 72.5% females) stayed in the hospital for 15.5 ± 17.1 days, and 18.8% (13/69) required further hospitalization during the ensuing months. Mortality was 11.6% within 30 days, coinciding with hospital mortality, and an additional 11.6% till one year, thus reaching 23.2%. Anemia, hypoalbuminemia and low transferrin, along with elevated glucose and urea were frequent, suggesting undernutrition with metabolic derangements. Reactance, urea and creatinine were different in patients suffering both early and late demise. Resistance, white blood cell count and osteoporosis were risk factors for early mortality only , and anemia exclusively for late mortality. Conclusions: Primitive bioimpedance measurements, which had not been hitherto investigated , were prognostically related to early and late mortality. These markers of disease-related malnutrition and especially reactance should be further studied in patients unfit for anthropometric evaluation due to fracture and immobility.Antecedentes: Los factores de riesgo para mortalidad en las fracturas de cadera involucran estado nutricional, nominalmente índice de masa corporal, pero no composición corporal. Considerándose la dificultad de evaluación antropométrica de pacientes acamados, un estudio prospectivo con bioimpedancia fue programado. Métodos: Pacientes de mayor edad con fractura de cadera fueron consecutivamente recrutados. Testes bioquímicos, medidas primitivas de bioimpedáncia (resisténcia, reactáncia, ángulo de fase) e seguimiento hasta un año fueron valorizados. Resultados: Los pacientes (N = 69, 81,2 ± 8,1 años, 72,5% mujeres) quedáronse en el hospital por 15,5 ± 17,1 días, y el 18,8% (13/69) necesitaron de hospitalización adicional en los meses siguientes. La mortalidad de 30 días fue 11,6%, coincidiendo con la mortalidad hospitalaria, con 11,6% adicionales hasta un año, alcanzando un total de 23,2%. Anemia, hipoalbuminemia e baja de transferrina, asimismo glucosa y urea elevadas, se observaron con frecuencia, compatibles con desnutrición e trastornos metabólicos. La reactáncia, urea y creatinina eran diferentes en pacientes con mortalidad precoz y tardía. La resistencia, recuento de leucocitos y presencia de osteoporosis indicaron mortalidad precoz solamente, y anemia solo la mortalidad de un año. Conclusiones: Las medidas primitivas de bioimpedáncia, que no habían sido hasta el momento investigadas en ese contexto, mostraronse pronosticamente relacionadas con mortalidad precoz y tardía. Estos marcadores y en especial la reactáncia merecen ser mas estudiados en pacientes donde la antropometria es difícil o imposible por razones de fractura y inmobilidad.

In this paper, we present a performance comparison of database replication techniques based on total order broadcast. While the performance of total order broadcast-based replication techniques has been studied in previous papers, this paper presents many new contributions. First, it compares with each other techniques that were presented and evaluated separately, usually by comparing them to a classical replication scheme like distributed locking. Second, the evaluation is done using a finer network model than previous studies. Third, the paper compares techniques that offer the same consistency criterion (one-copy serializability) in the same environment using the same settings. The paper shows that, while networking performance has little influence in a LAN setting, the cost of synchronizing replicas is quite high. Because of this, total order broadcast-based techniques are very promising as they minimize synchronization between replicas. Index Terms--Distributed databases, performance attributes, distributed programming.

Total order broadcast and multicast (also called atomic broadcast/multicast) present an important problem in distributed systems, especially with respect to fault-tolerance. In short, the primitive ensures that messages sent to a set of processes are, in turn, delivered by all those processes in the same total order. Categories and Subject Descriptors: C.2.4 [Computer-Communication Networks]: Distributed Systems; C.2.2 [Computer-Communication Networks]: Network Protocols--Applications; Protocol architecture; D.4.4 [Operating Systems]: Communications Management--Message sending; Network communication; D.4.5 [Operating Systems]: Reliability--Fault-tolerance; H.2.4 [Database Management]: Systems--Distributed databases; H.3.4 [Information Storage and Retrieval]: Systems and Software--Distributed systems General Terms: Algorithms, Reliability, Design Additional Key Words and Phrases: Distributed systems, distributed algorithms, group communication, fault-tolerance, agreement problems, message passing, total ordering, global ordering, atomic multicast, atomic broadcast, classification, taxonomy, survey The problem has inspired an abundance of literature, with a plethora of proposed algorithms. This article proposes a classification of total order broadcast and multicast algorithms based on their ordering mechanisms, and addresses a number of other important issues. The article surveys about sixty algorithms, thus providing by far the most extensive study of the problem so far. The article discusses algorithms for both the synchronous and the asynchronous system models, and studies the respective properties and behavior of the different algorithms.

Over the past years, mobile agent technology has attracted considerable attention, and a significant body of literature has been published. To further develop mobile agent technology, reliability mechanisms such as fault tolerance and transaction support are required. This article aims at structuring the field of fault-tolerant and transactional mobile agent execution and thus at guiding the reader to understand the basic strengths and weaknesses of existing approaches. It starts with a discussion on providing fault tolerance in a system in which processes simply fail. For this purpose, we first identify two basic requirements for fault-tolerant mobile agent execution: (1) non-blocking (i.e., a single failure does not prevent progress of the mobile agent execution) and (2) exactly-once (i.e., multiple executions of the agent are prevented). This leads us to introduce the notion of a local transaction as the basic building block for fault-tolerant mobile agent execution and to classify existing approaches according to when and by whom the local transactions are committed. In a second part, we show that transactional mobile agent execution additionally ensures execution atomicity and present a survey of existing approaches. In the last part of the survey, we extend the notion of fault tolerance to arbitrary Byzantine failures and security-related issues of the mobile agent execution. Categories and Subject Descriptors: A. 1 [General Literature]: Introductory and Survey; D. 1.3 [Programming Techniques]: Concurrent Programming--Distributed programming; D.2.11 [Software Engineering]: Software Architectures--Patterns (e.g., client/server, pipeline, blackboard); D.4.5 [Operating Systems]: Reliability-Checkpoint/restart; fault-tolerance; D.4.6 [Operating Systems]: Security and Protection--Cryptographic controls; invasive software General Terms: Reliability, Algorithms, Design, Theory Additional Key Words and Phrases: ACID, agreement problem, asynchronous system, Byzantine failures, commit, crash failures, fault tolerance, malicious places, mobile agents, replication, security, transaction

Atomic broadcast primitives are often proposed as a mechanism to allow fault-tolerant cooperation between sites in a distributed system. Unfortunately, the delay incurred before a message can be delivered makes it difficult to implement high performance, scalable applications on top of atomic broadcast primitives. Recently, a new approach has been proposed for atomic broadcast which, based on optimistic assumptions about the communication system, reduces the average delay for message delivery to the application. In this paper, we develop this idea further and show how applications can take even more advantage of the optimistic assumption by overlapping the coordination phase of the atomic broadcast algorithm with the processing of delivered messages. In particular, we present a replicated database architecture that employs the new atomic broadcast primitive in such a way that communication and transaction processing are fully overlapped, providing high performance without relaxing transaction correctness. Index Terms--Replicated databases, optimistic processing, atomic broadcast, transaction processing.

A pesquisa sobre a influência da representação social do idoso teve por objetivo analisar tal construto em grupos de idosos, institucionalizados ou não, de 60 a 90 anos, de vários níveis socioeconômicos. Três dimensões foram estudadas: a da sua influência nas modalidades de atendimento; nas atitudes dos profissionais que lidam com eles; e nos comportamentos interativos dos e com os idosos. Essa análise foi baseada nos elementos constitutivos do núcleo central desse construto que foram isolados, a fim de permitir o planejamento de uma intevenção de cunho preventivo e uma orientação mais adequada dos programas sócioeducativos.

A pesquisa sobre a influência da representação social do idoso teve por objetivo analisar tal construto em grupos de idosos, institucionalizados ou não, de 60 a 90 anos, de vários níveis socioeconômicos. Três dimensões foram estudadas: a da sua influência nas modalidades de atendimento; nas atitudes dos profissionais que lidam com eles; e nos comportamentos interativos dos e com os idosos. Essa análise foi baseada nos elementos constitutivos do núcleo central desse construto que foram isolados, a fim de permitir o planejamento de uma intevenção de cunho preventivo e uma orientação mais adequada dos programas sócioeducativos.

Background: Risk-factors for mortality in hip fractures encompass nutritional status, nominally body mass index, but not body composition. Given the difficulty of anthropometric assessment in bedridden patients a prospective study with bioimpedance analysis was designed. Methods: Elderly patients with hip fracture were consecutively recruited. Biochemical tests, primitive bioimpedance measurements (resistance, reactance and phase angle) and follow-up till one year were targeted. Results: Patients (N = 69, 81.2 ± 8.1 years old, 72.5% females) stayed in the hospital for 15.5 ± 17.1 days, and 18.8% (13/69) required further hospitalization during the ensuing months. Mortality was 11.6% within 30 days, coinciding with hospital mortality, and an additional 11.6% till one year, thus reaching 23.2%. Anemia, hypoalbuminemia and low transferrin, along with elevated glucose and urea were frequent, suggesting undernutrition with metabolic derangements. Reactance, urea and creatinine were different in patients suffering both early and late demise. Resistance, white blood cell count and osteoporosis were risk factors for early mortality only , and anemia exclusively for late mortality. Conclusions: Primitive bioimpedance measurements, which had not been hitherto investigated , were prognostically related to early and late mortality. These markers of disease-related malnutrition and especially reactance should be further studied in patients unfit for anthropometric evaluation due to fracture and immobility.

OBJECTIVES: Conventional imaging methods are excellent for the morphological characterization of the consequences of osteonecrosis; however, only specialized techniques have been considered useful for obtaining functional information. To explore the affinity of radiotracers for severely devascularized bone, a new mouse model of isolated femur implanted in a subcutaneous abdominal pocket was devised. To maintain animal mobility and longevity, the femur was harvested from syngeneic donors. Two technetium-99m-labeled tracers targeting angiogenesis and bone matrix were selected. METHODS: Medronic acid and a homodimer peptide conjugated with RGDfK were radiolabeled with technetium-99m, and biodistribution was evaluated in Swiss mice. The grafted and control femurs were evaluated after 15, 30 and 60 days, including computed tomography (CT) and histological analysis. RESULTS: Radiolabeling achieved high (>95%) radiochemical purity. The biodistribution confirmed good blood clearance 1 hour after administration. For 99mTc-hydrazinonicotinic acid (HYNIC)-E-[c(RGDfK)2, remarkable renal excretion was observed compared to 99mTc-methylene diphosphonate (MDP), but the latter, as expected, revealed higher bone uptake. The results obtained in the control femur were equal at all time points. In the implanted femur, 99mTc-HYNIC-E-[c(RGDfK)2 uptake was highest after 15 days, consistent with early angiogenesis. Regarding 99mTc-MDP in the implant, similar uptake was documented at all time points, consistent with sustained bone viability; however, the uptake was lower than that detected in the control femur, as confirmed by histology. CONCLUSIONS: 1) Graft viability was successfully diagnosed using radiotracers in severely ischemic bone at all time points. 2) Analogously, indirect information about angiogenesis could be gathered using 999mTc-HYNIC-E-[c(RGDfK)2. 3) These techniques appear promising and warrant further studies to determine their potential clinical applications.

Atomic broadcast is an important communication primitive often used to implement state machine replication. Despite the large number of atomic broadcast algorithms proposed in the literature, few papers have discussed how to turn these algorithms into efficient executable protocols. This paper focuses on a class of atomic broadcast algorithms based on Paxos, with its corresponding desirable properties: safety under asynchrony assumptions, liveness under weak synchrony assumptions and resiliency optimality. The paper presents two protocols, M-Ring Paxos and U-Ring Paxos, derived from Paxos. The protocols inherit the properties of Paxos and can be implemented very efficiently. We report a detailed performance analysis of M-Ring Paxos and U-Ring Paxos and compare them to other atomic broadcast protocols. [ABSTRACT FROM AUTHOR]

This paper investigates cache placement on a cooperative cache built from individual client caches in an online social network or web service. We use a service that maintains a mapping between content and the clients that cache it, and propose cache placement schemes that leverage relationships between clients (for example, social links) and workload statistics, proactively placing content on clients that are likely to access it. We evaluate efficacy through simulation, comparing our schemes against commonly used cache placement algorithms as well as optimal placement. We synthesize a workload to match characteristics of online social networks. Simulation results of our proposed caching schemes impose moderate network overhead and show considerable improvement to the client's cache hit ratio, even under churn. [ABSTRACT FROM PUBLISHER]