716 research outputs found
A Game of Simulation: Modeling and Analyzing the Dragons of Game of Thrones
This paper outlines two approaches for mathematical, simulation, modeling,
and analysis of hypothetical creatures, in particular, the dragons of HBO's
television series Game of Thrones (GOT). Our first approach, the forward model,
utilizes quasi-empirical observations of various features of GOT dragons. We
then mathematically derive the growth rate, other dimensions, energy
consumption, etc. In the backward model, we use projected energy consumption by
given ecological impact to model an expected dragon in terms of physical
features. We compare and contrast both models to examine the plausibility of a
real-world existence for our titular dragons and provide brief analyses of
potential impacts on ecology.Comment: 16 page
Analgesic prescribing trends in a national sample of older veterans with osteoarthritis: 2012-2017
Few investigations examine patterns of opioid and nonopioid analgesic prescribing and concurrent pain intensity ratings before and after institution of safer prescribing programs such as the October 2013 Veterans Health Administration system-wide Opioid Safety Initiative (OSI) implementation. We conducted a quasi-experimental pre–post observational study of all older U.S. veterans (≥50 years old) with osteoarthritis of the knee or hip. All associated outpatient analgesic prescriptions and outpatient pain intensity ratings from January 1, 2012 to December 31, 2016, were analyzed with segmented regression of interrupted time series. Standardized monthly rates for each analgesic class (total, opioid, nonsteroidal anti-inflammatory drug, acetaminophen, and other study analgesics) were analyzed with segmented negative binomial regression models with overall slope, step, and slope change. Similarly, segmented linear regression was used to analyze pain intensity ratings and percentage of those reporting pain. All models were additionally adjusted for age, sex, and race. Before OSI implementation, total analgesic prescriptions showed a steady rise, abruptly decreasing to a flat trajectory after OSI implementation. This trend was primarily due to a decrease in opioid prescribing after OSI. Total prescribing after OSI implementation was partially compensated by continuing increased prescribing of other study analgesics as well as a significant rise in acetaminophen prescriptions (post-OSI). No changes in nonsteroidal anti-inflammatory drug prescribing were seen. A small rise in the percentage of those reporting pain but not mean pain intensity ratings continued over the study period with no changes associated with OSI. Changes in analgesic prescribing trends were not paralleled by changes in reported pain intensity for older veterans with osteoarthritis
Biodemographic perspectives for epidemiologists
A new scientific discipline arose in the late 20(th )century known as biodemography. When applied to aging, biodemography is the scientific study of common age patterns and causes of death observed among humans and other sexually reproducing species and the biological forces that contribute to them. Biodemography is interdisciplinary, involving a combination of the population sciences and such fields as molecular and evolutionary biology. Researchers in this emerging field have discovered attributes of aging and death in humans that may very well change the way epidemiologists view and study the causes and expression of disease. In this paper, the biodemography of aging is introduced in light of traditional epidemiologic models of disease causation and death
Southern Foresters\u27 Perceptions of Climate Change: Implications for Educational Program Development
An understanding of foresters\u27 perceptions of climate change is important for developing effective educational programs on adaptive forest management. We surveyed 1,398 foresters in the southern United States regarding their perceptions of climate change, observations and concerns about climatic and forest conditions, and knowledge of and interest in resilient forest management techniques and climate science. A majority (61%) agreed that climate change is occurring, and 14% agreed that it is caused by humans. Most respondents were interested in learning more about forest resilience and related concepts. Development of programming focused on managing for forest resilience in a changing climate is a prudent educational approach that builds on familiar risk-management strategies
Quantification of image texture in X-ray phase-contrast-enhanced projection images of in vivo mouse lungs observed at varied inflation pressures
To date, there are very limited noninvasive, regional assays of in vivo lung microstructure near the alveolar level. It has been suggested that x-ray phase-contrast enhanced imaging reveals information about the air volume of the lung; however, the image texture information in these images remains underutilized. Projection images of in vivo mouse lungs were acquired via a tabletop, propagation-based, X-ray phase-contrast imaging system. Anesthetized mice were mechanically ventilated in an upright position. Consistent with previously published studies, a distinct image texture was observed uniquely within lung regions. Lung regions were automatically identified using supervised machine learning applied to summary measures of the image texture data. It was found that an unsupervised clustering within predefined lung regions colocates with expected differences in anatomy along the cranial-caudal axis in upright mice. It was also found that specifically selected inflation pressures-here, a purposeful surrogate of distinct states of mechanical expansion-can be predicted from the lung image texture alone, that the prediction model itself varies from apex to base and that prediction is accurate regardless of overlap with nonpulmonary structures such as the ribs, mediastinum, and heart. Cross-validation analysis indicated low inter-animal variation in the image texture classifications. Together, these results suggest that the image texture observed in a single X-ray phase-contrast-enhanced projection image could be used across a range of pressure states to study regional variations in regional lung function
Spectral statistics of the k-body random-interaction model
We reconsider the question of the spectral statistics of the k-body
random-interaction model, investigated recently by Benet, Rupp, and
Weidenmueller, who concluded that the spectral statistics are Poissonian. The
binary-correlation method that these authors used involves formal manipulations
of divergent series. We argue that Borel summation does not suffice to define
these divergent series without further (arbitrary) regularization, and that
this constitutes a significant gap in the demonstration of Poissonian
statistics. Our conclusion is that the spectral statistics of the k-body
random-interaction model remains an open question.Comment: 17 pages, no figure
Development that works, March 31, 2011
This repository item contains a single issue of the Pardee Conference Series, On March 31, 2011, more than 100 people participated in a conference titled
“Development That Works,” sponsored by Boston University’s Frederick S.
Pardee Center for the Study of the Longer-Range Future in collaboration with the
BU Global Development program. In the pages that follow, four essays written
by Boston University graduate students capture the salient points and overarching
themes from the four sessions, each of which featured presentations by
outstanding scholars and practitioners working in the field of development. The
conference agenda and speakers’ biographies are included following the essays.The theme and the title of the conference—”Development That Works”—stemmed from the conference organizers’ desire to explore, from a groundlevel perspective, what programs, policies, and practices have been shown—or appear to have the potential—to achieve sustained, long-term advances in
development in various parts of the world. The intent was not to simply showcase
“success stories,” but rather to explore the larger concepts and opportunities
that have resulted in development that is meaningful and sustainable
over time. The presentations and discussions focused on critical assessments
of why and how some programs take hold, and what can be learned from
them. From the influence of global economic structures to innovative private sector
programs and the need to evaluate development programs at the
“granular” level, the expert panelists provided well-informed and often provocative
perspectives on what is and isn’t working in development programs
today, and what could work better in the future
The depression in visual impairment trial (DEPVIT): trial design and protocol
<b>Background</b>
The prevalence of depression in people with a visual disability is high but screening for depression and referral for treatment is not yet an integral part of visual rehabilitation service provision. One reason for this may be that there is no good evidence about the effectiveness of treatments in this patient group. This study is the first to evaluate the effect of depression treatments on people with a visual impairment and co morbid depression.<p></p>
<b>Methods/design</b>
The study is an exploratory, multicentre, individually randomised waiting list controlled trial. Participants will be randomised to receive Problem Solving Therapy (PST), a ‘referral to the GP’ requesting treatment according to the NICE’s ‘stepped care’ recommendations or the waiting list arm of the trial. The primary outcome measure is change (from randomisation) in depressive symptoms as measured by the Beck’s Depression Inventory (BDI-II) at 6 months. Secondary outcomes include change in depressive symptoms at 3 months, change in visual function as measured with the near vision subscale of the VFQ-48 and 7 item NEI-VFQ at 3 and 6 months, change in generic health related quality of life (EQ5D), the costs associated with PST, estimates of incremental cost effectiveness, and recruitment rate estimation.<p></p>
<b>Discussion</b>
Depression is prevalent in people with disabling visual impairment. This exploratory study will establish depression screening and referral for treatment in visual rehabilitation clinics in the UK. It will be the first to explore the efficacy of PST and the effectiveness of NICE’s ‘stepped care’ approach to the treatment of depression in people with a visual impairment.<p></p>
Community and Ecosystem-level Changes in a Species-rich Tallgrass Prairie Restoration
Changes in the plant community and ecosystem properties that follow the conversion of agriculture to restored tallgrass prairies are poorly understood. Beginning in 1995, we established a species-rich, restored prairie chronosequence where -3 ha of agricultural land have been converted to tallgrass prairie each year. Our goals were to examine differences in ecosystem properties between these restored prairies and adjacent agricultural fields and to determine changes in, and potential interactions between, the plant community and ecosystem properties that occur over time in the restored prairies. During the summers of 2000-2002, we examined species cover, soil C and N, potential net C and N mineralization, litter mass, soil texture, and bulk density across the 6- to 8-year-old prairie chronosequence and adjacent agricultural fields in southern Minnesota. We also established experimentally fertilized, watered, and control plots in the prairie chronosequence to examine the degree of nitrogen limitation on aboveground and belowground net primary production (ANPP and BNPP). Large shifts in functional diversity occurred within three growing seasons. First-year prairies were dominated by annuals and biennials. By the second growing season, perennial native composites had become dominant, followed by a significant shift to warm-season C4 grasses in prairies ?3 yr old. Ecosystem properties that changed with the rise of C4 grasses included increased BNPP, litter mass, and C mineralization rates and decreased N mineralization rates. ANPP increased significantly with N fertilization but did not vary between young and old prairies with dramatically different plant community composition. Total soil C and N were not significantly different between prairie and agricultural soils in the depths examined (0-10, 10-20, 20-35, 35-50, 50-65 cm). We compared the results from our species-rich prairie restoration to published data on ecosystem function in other restored grasslands, such as Conservation Reserve Program (CRP) and old-field successional sites. Results suggest that rapid changes in functional diversity can have large impacts on ecosystem-level properties, causing community- and system-level dynamics in species-rich prairie restorations to converge with those from low-diversity managed grasslands
Searching for evidence in public health emergencies: a white paper of best practices
Objectives: Information professionals have supported medical providers, administrators and decision-makers, and guideline creators in the COVID-19 response. Searching COVID-19 literature presented new challenges, including the volume and heterogeneity of literature and the proliferation of new information sources, and exposed existing issues in metadata and publishing. An expert panel developed best practices, including recommendations, elaborations, and examples, for searching during public health emergencies.
Methods: Project directors and advisors developed core elements from experience and literature. Experts, identified by affiliation with evidence synthesis groups, COVID-19 search experience, and nomination, responded to an online survey to reach consensus on core elements. Expert participants provided written responses to guiding questions. A synthesis of responses provided the foundation for focus group discussions. A writing group then drafted the best practices into a statement. Experts reviewed the statement prior to dissemination.
Results: Twelve information professionals contributed to best practice recommendations on six elements: core resources, search strategies, publication types, transparency and reproducibility, collaboration, and conducting research. Underlying principles across recommendations include timeliness, openness, balance, preparedness, and responsiveness.
Conclusions: The authors and experts anticipate the recommendations for searching for evidence during public health emergencies will help information specialists, librarians, evidence synthesis groups, researchers, and decision-makers respond to future public health emergencies, including but not limited to disease outbreaks. The recommendations complement existing guidance by addressing concerns specific to emergency response. The statement is intended as a living document. Future revisions should solicit input from a broader community and reflect conclusions of meta-research on COVID-19 and health emergencies
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