130 research outputs found
Recommended from our members
Managing Uncertainty in Rule-based Reasoning
There are two major problems associated with propagation of uncertainty in the rule-based modeling of human reasoning. O n e concerns how the possibly uncertain evidence in a rule's antecedents affects the rule's conclusion. The other concerns the issue of combining evidence across rules having the same conclusion. Two experiments were conducted in which psychological data were compared with a variety of mathematical models for managing uncertainty. Results of an experiment on the fu-st problem suggested that the certainty of the antecedents in a production rule can be summarized by the maximum of disjunctively connected antecedents and the minimum of conjunctively connected antecedents {maximin summarizing), and that the m a x i m u m certainty of the rule's conclusion can be scaled down by multiplication with the results of that summary{multiplication scaling). A second experiment suggested that the second problem can be solved with Heckerman's modified certainty factor model which sums the certainties contributed by each of two rules and divides by 1 plus their product
Healthcare-use for Major Infectious Disease Syndromes in an Informal Settlement in Nairobi, Kenya
A healthcare-use survey was conducted in the Kibera informal settlement in Nairobi, Kenya, in July 2005 to inform subsequent surveillance in the site for infectious diseases. Sets of standardized questionnaires were administered to 1,542 caretakers and heads of households with one or more child(ren) aged less than five years. The average household-size was 5.1 (range 1-15) persons. Most (90%) resided in a single room with monthly rents of US$ 4.50-7.00. Within the previous two weeks, 49% of children (n=1,378) aged less than five years (under-five children) and 18% of persons (n=1,139) aged ≥5 years experienced febrile, diarrhoeal or respiratory illnesses. The large majority (>75%) of illnesses were associated with healthcare-seeking. While licensed clinics were the most-frequently visited settings, kiosks, unlicensed care providers, and traditional healers were also frequently visited. Expense was cited most often (50%) as the reason for not seeking healthcare. Of those who sought healthcare, 34-44% of the first and/or the only visits were made with non-licensed care providers, potentially delaying opportunities for early optimal intervention. The proportions of patients accessing healthcare facilities were higher with diarrhoeal disease and fever (but not for respiratory diseases in under-five children) than those reported from a contemporaneous study conducted in a rural area in Kenya. The findings support community-based rather than facility-based surveillance in this setting to achieve objectives for comprehensive assessment of the burden of disease
Healthcare-use for Major Infectious Disease Syndromes in an Informal Settlement in Nairobi, Kenya
A healthcare-use survey was conducted in the Kibera informal settlement
in Nairobi, Kenya, in July 2005 to inform subsequent surveillance in
the site for infectious diseases. Sets of standardized questionnaires
were administered to 1,542 caretakers and heads of households with one
or more child(ren) aged less than five years. The average
household-size was 5.1 (range 1-15) persons. Most (90%) resided in a
single room with monthly rents of US$ 4.50-7.00. Within the previous
two weeks, 49% of children (n=1,378) aged less than five years
(under-five children) and 18% of persons (n=1,139) aged 655 years
experienced febrile, diarrhoeal or respiratory illnesses. The large
majority (>75%) of illnesses were associated with healthcareseeking.
While licensed clinics were the most-frequently visited settings,
kiosks, unlicensed care providers, and traditional healers were also
frequently visited. Expense was cited most often (50%) as the reason
for not seeking healthcare. Of those who sought healthcare, 34-44% of
the first and/or the only visits were made with non-licensed care
providers, potentially delaying opportunities for early optimal
intervention. The proportions of patients accessing healthcare
facilities were higher with diarrhoeal disease and fever (but not for
respiratory diseases in under-five children) than those reported from a
contemporaneous study conducted in a rural area in Kenya. The findings
support community-based rather than facility-based surveillance in this
setting to achieve objectives for comprehensive assessment of the
burden of disease
Towards controlling the solid state valence tautomeric interconversion character by solvation
Crystals of [Co<i>(diox)</i><sub>2</sub>(4-NO<sub>2</sub>-py)<sub>2</sub>] (<b>1</b>) and [Co<i>(diox)</i><sub>2</sub>(4-CN-py)<sub>2</sub>] (<b>2</b>) where <i>diox</i> are the <i>o</i>-dioxolene 3,5-di-<i>t</i>-butylsemiquinonate (SQ<sup>•–</sup>) and/or
3,5-di-<i>t</i>-butylcatecholate (Cat<sup>2–</sup>) ions, 4-NO<sub>2</sub>-py is 4-nitro-pyridine, 4-CN-py is 4-cyano-pyridine,
are among the few known crystals presenting both thermally induced
and photoinduced <i>ls</i>-[M<sup>+3</sup>(SQ<sup>•–</sup>)(Cat<sup>2–</sup>)] ↔ <i>hs</i>-[M<sup>2+</sup>(SQ<sup>•–</sup>)<sub>2</sub>] valence tautomeric
interconversion (VTI). In <b>2</b>, the thermal-induced VTI
is cooperative, characterizing an abrupt conversion, and in <b>1</b> it is noncooperative. In this work, crystals of [Co<i>(diox)</i><sub>2</sub>(4-NO<sub>2</sub>-py)<sub>2</sub>]·benzene (<b>1BZ</b>), [Co<i>(diox)</i><sub>2</sub>(4-NO<sub>2</sub>-py)<sub>2</sub>]·toluene
(<b>1TL</b>), [Co<i>(diox)</i><sub>2</sub>(4-CN-py)<sub>2</sub>]·benzene (<b>2BZ</b>), and [Co<i>(diox)</i><sub>2</sub>(4-CN-py)<sub>2</sub>]·toluene (<b>2TL</b>) have been prepared and analyzed by single crystal X-ray
diffraction in order to investigate how solvation modulates thermally
induced VTI. Crystallographic data were also successfully used together
with the two-state equilibrium equation to estimate Δ<i>H</i>° and Δ<i>S</i>° VTI thermodynamic
parameters. The solvate crystals, like the nonsolvated ones, present
essentially reversible thermally induced VTI. The <b>1TL</b> crystal presents the same monoclinic symmetry and the same intermolecular
hydrogen-bonded network of <b>1</b>, and both present a noncooperative
thermal-induced VTI. The <b>1BZ</b> crystal has triclinic symmetry
and presents a cooperative VTI with a thermal hysteresis of ∼30
K. In contrast to <b>2</b>, thermally induced VTI in <b>2BZ</b> and <b>2TL</b> is noncooperative despite the fact that <b>2</b>, <b>2BZ</b>, and <b>2TL</b> crystals exhibit
the same monoclinic symmetry and the same intermolecular hydrogen-bonded
network. In <b>2BZ</b> and <b>2TL</b> benzene and toluene
molecules as well as the <i>t</i>-butyl groups of the <i>o</i>-dioxolene molecules convert gradually from being dynamically
disordered at about 300 K to a static disorder state below 150 K.
The layer separation distance of interacting [Co<i>(diox)</i><sub>2</sub>(4-X-py)<sub>2</sub>], X = CN and NO<sub>2</sub>, molecules in all solvate crystals is ∼15 Å, whereas
in <b>2</b>, which presents cooperative VTI, it is ∼12
Å. An order–disorder component might account for the stabilization
of the metastable <i>hs</i>-Co<sup>2+</sup> state in <b>2BZ</b> and in <b>2TL</b>, but no disorder was found in
the <b>1TL</b> crystals. Therefore, the lack of cooperativity
in the thermally induced VTI in these crystals seems to be due to
the large distance between the layers of interacting molecules. Cooperativity
in the VTI of <b>1BZ</b> crystal is likely to be related with
the unique molecular bond scheme network that connects neighboring
active [Co<i>(diox)</i><sub>2</sub>(4-NO<sub>2</sub>-py)<sub>2</sub>] molecules through the <i>o</i>-dioxolene
oxygen atoms bonded directly to the Co ion
Putting surveillance data into context: The role of health care utilization surveys in understanding population burden of pneumonia in developing countries
AbstractBackgroundSurveillance is essential to estimating the global burden of pneumonia, yet differences in surveillance methodology and health care-seeking behaviors limit inter-country comparisons.MethodsResults were compared from community surveys measuring health care-seeking for pneumonia defined as: (1) cough and difficulty breathing for ⩾2days; or, (2) provider-diagnosed pneumonia. Surveys were conducted in six sites in Guatemala, Kenya and Thailand; these sites also conduct, active, hospital- and population-based disease surveillance for pneumonia.ResultsFrequency of self-reported pneumonia during the preceding year ranged from 1.1% (Thailand) to 6.3% (Guatemala) and was highest in children aged <5years and in urban sites. The proportion of persons with pneumonia who sought hospital-based medical services ranged from 12% (Guatemala, Kenya) to 80% (Thailand) and was highest in children <5years of age. Hospitals and private provider offices were the most common places where persons with pneumonia sought health care. The most commonly cited reasons for not seeking health care were: (a) mild illness; (b) already recovering; and (3) cost of treatment.ConclusionsHealth care-seeking patterns varied widely across countries. Using results from standardized health care utilization surveys to adjust facility-based surveillance estimates of pneumonia allows for more accurate and comparable estimates
Decrease in plasma miR-27a and miR-221 after concussion in Australian football players
Introduction: Sports-related concussion (SRC) is a common form of brain injury that lacks reliable methods to guide clinical decisions. MicroRNAs (miRNAs) can influence biological processes involved in SRC, and measurement of miRNAs in biological fluids may provide objective diagnostic and return to play/recovery biomarkers. Therefore, this prospective study investigated the temporal profile of circulating miRNA levels in concussed male and female athletes. Methods: Pre-season baseline blood samples were collected from amateur Australian rules football players (82 males, 45 females). Of these, 20 males and 8 females sustained an SRC during the subsequent season and underwent blood sampling at 2-, 6- and 13-days post-injury. A miRNA discovery Open Array was conducted on plasma to assess the expression of 754 known/validated miRNAs. miRNA target identified were further investigated with quantitative real-time PCR (qRT-PCR) in a validation study. Data pertaining to SRC symptoms, demographics, sporting history, education history and concussion history were also collected. Results: Discovery analysis identified 18 candidate miRNA. The consequent validation study found that plasma miR-221-3p levels were decreased at 6d and 13d, and that miR-27a-3p levels were decreased at 6d, when compared to baseline. Moreover, miR-27a and miR-221-3p levels were inversely correlated with SRC symptom severity. Conclusion: Circulating levels of miR-27a-3p and miR-221-3p were decreased in the sub-acute stages after SRC, and were inversely correlated with SRC symptom severity. Although further studies are required, these analyses have identified miRNA biomarker candidates of SRC severity and recovery that may one day assist in its clinical management
Identification of a humanized mouse model for functional testing of immune-mediated biomaterial foreign body response.
Biomedical devices comprise a major component of modern medicine, however immune-mediated fibrosis and rejection can limit their function over time. Here, we describe a humanized mouse model that recapitulates fibrosis following biomaterial implantation. Cellular and cytokine responses to multiple biomaterials were evaluated across different implant sites. Human innate immune macrophages were verified as essential to biomaterial rejection in this model and were capable of cross-talk with mouse fibroblasts for collagen matrix deposition. Cytokine and cytokine receptor array analysis confirmed core signaling in the fibrotic cascade. Foreign body giant cell formation, often unobserved in mice, was also prominent. Last, high-resolution microscopy coupled with multiplexed antibody capture digital profiling analysis supplied spatial resolution of rejection responses. This model enables the study of human immune cell-mediated fibrosis and interactions with implanted biomaterials and devices
Early Pastoral Economies and Herding Transitions in Eastern Eurasia
While classic models for the emergence of pastoral groups in Inner Asia describe mounted, horse-borne herders sweeping across the Eurasian Steppes during the Early or Middle Bronze Age (ca. 3000-1500 BCE), the actual economic basis of many early pastoral societies in the region is poorly characterized. In this paper, we use collagen mass fingerprinting and ancient DNA analysis of some of the first stratified and directly dated archaeofaunal assemblages from Mongolia's early pastoral cultures to undertake species identifications of this rare and highly fragmented material. Our results provide evidence for livestock-based, herding subsistence in Mongolia during the late 3rd and early 2nd millennia BCE. We observe no evidence for dietary exploitation of horses prior to the late Bronze Age, ca. 1200 BCE - at which point horses come to dominate ritual assemblages, play a key role in pastoral diets, and greatly influence pastoral mobility. In combination with the broader archaeofaunal record of Inner Asia, our analysis supports models for widespread changes in herding ecology linked to the innovation of horseback riding in Central Asia in the final 2nd millennium BCE. Such a framework can explain key broad-scale patterns in the movement of people, ideas, and material culture in Eurasian prehistory
Local Orientation and the Evolution of Foraging: Changes in Decision Making Can Eliminate Evolutionary Trade-offs
Information processing is a major aspect of the evolution of animal behavior. In foraging, responsiveness to local feeding opportunities can generate patterns of behavior which reflect or “recognize patterns” in the environment beyond the perception of individuals. Theory on the evolution of behavior generally neglects such opportunity-based adaptation. Using a spatial individual-based model we study the role of opportunity-based adaptation in the evolution of foraging, and how it depends on local decision making. We compare two model variants which differ in the individual decision making that can evolve (restricted and extended model), and study the evolution of simple foraging behavior in environments where food is distributed either uniformly or in patches. We find that opportunity-based adaptation and the pattern recognition it generates, plays an important role in foraging success, particularly in patchy environments where one of the main challenges is “staying in patches”. In the restricted model this is achieved by genetic adaptation of move and search behavior, in light of a trade-off on within- and between-patch behavior. In the extended model this trade-off does not arise because decision making capabilities allow for differentiated behavioral patterns. As a consequence, it becomes possible for properties of movement to be specialized for detection of patches with more food, a larger scale information processing not present in the restricted model. Our results show that changes in decision making abilities can alter what kinds of pattern recognition are possible, eliminate an evolutionary trade-off and change the adaptive landscape
- …