4,226 research outputs found
The Economic Archaeology of Roman Economic Performance
Recent years have witnessed a paradigm shift in the study of the Roman economy. Methodologically modern economic analysis is now far more acceptable than it once was, and archaeology has become the major source of empirical data for many questions. On the substantive side there is now a far clearer appreciation of the major changes that the Roman economy underwent, with substantial growth of population and aggregate production and even some improvements in standard of living, but followed by equally dramatic decline. This economic success was not limited to the imperial core, but also extended to the provinces
Patient safety in developing countries: retrospective estimation of scale and nature of harm to patients in hospital
OBJECTIVE: To assess the frequency and nature of adverse events to patients in selected hospitals in developing or transitional economies. DESIGN: Retrospective medical record review of hospital admissions during 2005 in eight countries. SETTING: Ministries of Health of Egypt, Jordan, Kenya, Morocco, Tunisia, Sudan, South Africa and Yemen; the World Health Organisation (WHO) Eastern Mediterranean and African Regions (EMRO and AFRO), and WHO Patient Safety. PARTICIPANTS: Convenience sample of 26 hospitals from which 15,548 patient records were randomly sampled. MAIN OUTCOME MEASURES: Two stage screening. Initial screening based on 18 explicit criteria. Records that screened positive were then reviewed by a senior physician for determination of adverse event, its preventability, and the resulting disability. RESULTS: Of the 15,548 records reviewed, 8.2% showed at least one adverse event, with a range of 2.5% to 18.4% per country. Of these events, 83% were judged to be preventable, while about 30% were associated with death of the patient. About 34% adverse events were from therapeutic errors in relatively non-complex clinical situations. Inadequate training and supervision of clinical staff or the failure to follow policies or protocols contributed to most events. CONCLUSIONS: Unsafe patient care represents a serious and considerable danger to patients in the hospitals that were studied, and hence should be a high priority public health problem. Many other developing and transitional economies will probably share similar rates of harm and similar contributory factors. The convenience sampling of hospitals might limit the interpretation of results, but the identified adverse event rates show an estimate that should stimulate and facilitate the urgent institution of appropriate remedial action and also to trigger more research. Prevention of these adverse events will be complex and involves improving basic clinical processes and does not simply depend on the provision of more resources
Relationship of Enhanced Liver Fibrosis Score with Pediatric Nonalcoholic Fatty Liver Disease Histology and Response to Vitamin E or Metformin
OBJECTIVES:
To study the diagnostic performance of the enhanced liver fibrosis score (ELF) for detecting different stages of fibrosis and its usefulness in detecting histologic response to vitamin E or metformin in children with nonalcoholic fatty liver disease who participated in the Vitamin E or Metformin for the Treatment Of NAFLD In Children (TONIC) trial.
STUDY DESIGN:
ELF was measured at baseline and weeks 24, 48, and 96 on sera from 166 TONIC participants. Associations between ELF with baseline and end of trial (EOT) fibrosis stages and other histologic features were assessed using χ2 tests and logistic regression models.
RESULTS:
ELF was significantly associated with severity of fibrosis at baseline and EOT. ELF areas under the curve for discriminating patients with clinically significant and advanced fibrosis were 0.70 (95% CI, 0.60-0.80) and 0.79 (95% CI, 0.69-0.89), respectively. A 1-unit decrease in ELF at EOT was associated with overall histologic improvement (OR, 1.86; 95% CI, 1.11-3.14; P = .02), resolution of steatohepatitis (OR, 1.88; 95% CI, 1.09-3.25; P = .02), improvement in steatosis grade (OR, 1.76; 95% CI, 1.06-2.82; P = .03), and hepatocellular ballooning (OR, 1.79; 95% CI, 1.06-3.00; P = .03), but not with improvement in fibrosis stage (OR, 1.26; 95% CI, 0.78-2.03; P = .34).
CONCLUSIONS:
ELF was associated with fibrosis stage in children who participated in TONIC. Although not associated with improvement in fibrosis, a decrease in ELF at EOT was associated with Nonalcoholic Steatohepatitis resolution and improvement in nonalcoholic fatty liver disease histology. ELF may be a useful noninvasive test to monitor treatment response in children with nonalcoholic fatty liver disease
Tackling Exascale Software Challenges in Molecular Dynamics Simulations with GROMACS
GROMACS is a widely used package for biomolecular simulation, and over the
last two decades it has evolved from small-scale efficiency to advanced
heterogeneous acceleration and multi-level parallelism targeting some of the
largest supercomputers in the world. Here, we describe some of the ways we have
been able to realize this through the use of parallelization on all levels,
combined with a constant focus on absolute performance. Release 4.6 of GROMACS
uses SIMD acceleration on a wide range of architectures, GPU offloading
acceleration, and both OpenMP and MPI parallelism within and between nodes,
respectively. The recent work on acceleration made it necessary to revisit the
fundamental algorithms of molecular simulation, including the concept of
neighborsearching, and we discuss the present and future challenges we see for
exascale simulation - in particular a very fine-grained task parallelism. We
also discuss the software management, code peer review and continuous
integration testing required for a project of this complexity.Comment: EASC 2014 conference proceedin
Genetic context determines susceptibility to intraocular pressure elevation in a mouse pigmentary glaucoma
BACKGROUND: DBA/2J (D2) mice develop an age-related form of glaucoma. Their eyes progressively develop iris pigment dispersion and iris atrophy followed by increased intraocular pressure (IOP) and glaucomatous optic nerve damage. Mutant alleles of the Gpnmb and Tyrp1 genes are necessary for the iris disease, but it is unknown whether alleles of other D2 gene(s) are necessary for the distinct later stages of disease. We initiated a study of congenic strains to further define the genetic requirements and disease mechanisms of the D2 glaucoma. RESULTS: To further understand D2 glaucoma, we created congenic strains of mice on the C57BL/6J (B6) genetic background. B6 double-congenic mice carrying D2-derived Gpnmb and Tyrp1 mutations develop a D2-like iris disease. B6 single-congenics with only the Gpnmb and Tyrp1 mutations develop milder forms of iris disease. Genetic epistasis experiments introducing a B6 tyrosinase mutation into the congenic strains demonstrated that both the single and double-congenic iris diseases are rescued by interruption of melanin synthesis. Importantly, our experiments analyzing mice at ages up to 27 months indicate that the B6 double-congenic mice are much less prone to IOP elevation and glaucoma than are D2 mice. CONCLUSION: As demonstrated here, the Gpnmb and Tyrp1 iris phenotypes are both individually dependent on tyrosinase function. These results support involvement of abnormal melanosomal events in the diseases caused by each gene. In the context of the inbred D2 mouse strain, the glaucoma phenotype is clearly influenced by more genes than just Gpnmb and Tyrp1. Despite the outward similarity of pigment-dispersing iris disease between D2 and the B6 double-congenic mice, the congenic mice are much less susceptible to developing high IOP and glaucoma. These new congenic strains provide a valuable new resource for further studying the genetic and mechanistic complexity of this form of glaucoma
A Web-Based Flexible Communication System in Radiology
A web-based system for rapid multidirectional communication has been created in the Radiology department at San Francisco General Hospital. The system allows messaging among radiology attendings, residents, and technologists, as well as other members of the hospital community, such as Emergency Department physicians and nurses. Instead of being tied to a particular workflow, this system provides a flexible communication infrastructure which can be easily adapted for different functions and user roles. The system has so far been configured to successfully support the standard “wet reading” workflow, to support marking and tracking of critical results, as well as multiple educational and quality improvement workflows. In the 19 months of operation, the system has gained over 1,800 users (virtually all providers at our institution), it has been accessed by radiologists over 39,000 times and by non-radiologists over 34,000 times. It has become an integral part of the radiology department operations and non-radiology clinical workflows. Unlike most existing softwares, our system is not a task-specific application, but a multipurpose communication system. It is able to effectively accommodate multiple workflows and user roles through configuration (without additional programming). This flexibility has helped this system to be rapidly and widely adopted within our enterprise. The extended reach of the system enables improved monitoring and documentation of workflows, helping with management decision making, and quality assurance. We report a successful radiology communication system based on the principles of flexibility and inclusiveness of users inside and outside the radiology department
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Biotic carbon feedbacks in a materially-closed soil-vegetation-atmosphere system
The magnitude and direction of the coupled feedbacks between the biotic and abiotic components of the terrestrial carbon cycle is a major source of uncertainty in coupled climate–carbon-cycle models1, 2, 3. Materially closed, energetically open biological systems continuously and simultaneously allow the two-way feedback loop between the biotic and abiotic components to take place4, 5, 6, 7, but so far have not been used to their full potential in ecological research, owing to the challenge of achieving sustainable model systems6, 7. We show that using materially closed soil–vegetation–atmosphere systems with pro rata carbon amounts for the main terrestrial carbon pools enables the establishment of conditions that balance plant carbon assimilation, and autotrophic and heterotrophic respiration fluxes over periods suitable to investigate short-term biotic carbon feedbacks. Using this approach, we tested an alternative way of assessing the impact of increased CO2 and temperature on biotic carbon feedbacks. The results show that without nutrient and water limitations, the short-term biotic responses could potentially buffer a temperature increase of 2.3 °C without significant positive feedbacks to atmospheric CO2. We argue that such closed-system research represents an important test-bed platform for model validation and parameterization of plant and soil biotic responses to environmental changes
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