233 research outputs found
The Acanthocephalan Parasites of Eider Ducks
Because of their wide geographical distribution through arctic and subarctic regions of the northern hemisphere, the eider ducks offer some unusual opportunities for the study .of distribution and hostrelations of their parasites. When the Acanthocephala from eider ducks were first studied, the fauna of each continent was regarded as distinct, because it had been reasonably well established that the majority of species of these parasites encounter~d in the United States were distinct from those found in central Europe. This belief failed to take into account the fact that in the arctic the usual distributional bartl:ers to both the definitive and the intermediate hosts are lacking. Recent studies -in northern Europe, especially by Lundstrom (1941, 1942), and Dew collections. on the American continent have added significantly to an understanding, of .:this fauna. The new evidencesmake it seem apparent that for water\u27 birds of the arctic region the acanthocephalan parasites are very widely distrilmted -geographically. This statement does not contradict the generalization that migratory birds have little influence on inter-continental distribution of acanthocephalan parasites. It seems more probable that suitable intermediate hosts for Acanthocephala are widely dispersed in the arctic and subarctic regions and that local bird populations, even though they may have undergone subspecific or specific differentiation, are by food habits and habitat exposed to infection by identical species of parasites on the two continents. This condition of birds under ecologically similar conditions is a direct parallel to that described for fishes of the same regions where numerous species on the two continents serve as definitive hosts for Neoechinorhynchus rutili (Mueller) as demonstrated by Van Cleave and Lynch (1950)
The Acanthocephalan Parasites of Eider Ducks
Because of their wide geographical distribution through arctic and subarctic regions of the northern hemisphere, the eider ducks offer some unusual opportunities for the study .of distribution and hostrelations of their parasites. When the Acanthocephala from eider ducks were first studied, the fauna of each continent was regarded as distinct, because it had been reasonably well established that the majority of species of these parasites encounter~d in the United States were distinct from those found in central Europe. This belief failed to take into account the fact that in the arctic the usual distributional bartl:ers to both the definitive and the intermediate hosts are lacking. Recent studies -in northern Europe, especially by Lundstrom (1941, 1942), and Dew collections. on the American continent have added significantly to an understanding, of .:this fauna. The new evidencesmake it seem apparent that for water\u27 birds of the arctic region the acanthocephalan parasites are very widely distrilmted -geographically. This statement does not contradict the generalization that migratory birds have little influence on inter-continental distribution of acanthocephalan parasites. It seems more probable that suitable intermediate hosts for Acanthocephala are widely dispersed in the arctic and subarctic regions and that local bird populations, even though they may have undergone subspecific or specific differentiation, are by food habits and habitat exposed to infection by identical species of parasites on the two continents. This condition of birds under ecologically similar conditions is a direct parallel to that described for fishes of the same regions where numerous species on the two continents serve as definitive hosts for Neoechinorhynchus rutili (Mueller) as demonstrated by Van Cleave and Lynch (1950)
Why the Soviets Violate Arms Control Treaties, and Nuclear Weapons, Policies and the Test Ban Issue
Planet Hunters: Assessing the Kepler Inventory of Short Period Planets
We present the results from a search of data from the first 33.5 days of the
Kepler science mission (Quarter 1) for exoplanet transits by the Planet Hunters
citizen science project. Planet Hunters enlists members of the general public
to visually identify transits in the publicly released Kepler light curves via
the World Wide Web. Over 24,000 volunteers reviewed the Kepler Quarter 1 data
set. We examine the abundance of \geq 2 R\oplus planets on short period (< 15
days) orbits based on Planet Hunters detections. We present these results along
with an analysis of the detection efficiency of human classifiers to identify
planetary transits including a comparison to the Kepler inventory of planet
candidates. Although performance drops rapidly for smaller radii, \geq 4
R\oplus Planet Hunters \geq 85% efficient at identifying transit signals for
planets with periods less than 15 days for the Kepler sample of target stars.
Our high efficiency rate for simulated transits along with recovery of the
majority of Kepler \geq 4 R\oplus planets suggest suggests the Kepler inventory
of \geq 4 R\oplus short period planets is nearly complete.Comment: 41 pages,13 figures, 8 tables, accepted to Ap
The development, usability, and reliability of the Electronic Patient Visit Assessment (ePVA) for head and neck cancer
Background: Annually, over 65,000 persons are diagnosed with head and neck cancer in the United States. During treatment, up to 50% of patients become severely symptomatic with pain, fatigue, mouth sores, and inability to eat. Long term complications are lymphedema, fibrosis, dysphagia, and musculoskeletal impairment. Patients’ ability to perform daily activities and to interact socially may be impaired, resulting in poor quality of life. A pragmatic, clinically useful assessment is needed to ensure early detection and intervention for patients to report symptoms and functional limitations over time. We developed the Electronic Patient Visit Assessment (ePVA) that enables patients to report 42 symptoms related to head and neck cancer and 17 limitations of functional status. This manuscript reports (I) the development of the ePVA, (II) the content validity of the ePVA, and (III) the usability and reliability of the ePVA. Methods: Usability was evaluated using the “Think Aloud” technique to guide the iterative process to refine the ePVA based on participants’ evaluations. After signing the informed consent, 30 participants with head and neck cancer completed the ePVA using digital tablet devices while thinking aloud about ease of use. All patient conversations were recorded and professionally transcribed. Reliability of the ePVA symptom and functional limitation measures was estimated using the Kuder-Richardson test. Convergent validity of the ePVA was evaluated using the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 global QoL/health scale. Transcribed qualitative data were analyzed using directed content analysis approach. Quantitative analyses consisted of descriptive statistics and correlation analyses. Results: Among participants, 90% strongly agreed or agreed that the ePVA system was easy to use and 80% were very satisfied. Only minor usability problems were reported due to formatting and software “bugs”. Reporting of usability problems decreased in frequency over the study period and no usability problems were reported by the last 3 participants who completed the ePVA. Based on participants’ suggestions during the iterative process, refinement of the ePVA included increased touch sensitivity of the touch screen technology and customized error messages to improve ease of use. The ePVA also recorded patient reported symptoms (mouth symptoms: 93%, fibrosis: 60%, fatigue: 60%). The ePVA demonstrated acceptable reliability (alpha =0.82–0.85) and convergent validity (ePVA total number of reported symptoms and function limitations was negatively correlated with EORTC QLQ-C30 global QOL/health scale: r=−0.55038, P<0.01). Conclusions: The ePVA was rigorously developed, accepted by patients with satisfaction, and demonstrated acceptable reliability and convergent validity. Future research will use data generated by the ePVA to determine the impact of symptom trajectories on functional status, treatment interruptions and terminations, and health resource use in head and neck cancer
The usefulness of the electronic patient visit assessment (ePVA) as a clinical support tool for real-time interventions in head and neck cancer
Background: Patients with head and neck cancer (HNC) experience painful, debilitating symptoms and functional limitations that can interrupt cancer treatment, and decrease their health-related quality of life (HRQoL). The Electronic Patient Visit Assessment (ePVA) for head and neck is a web-based mHealth patient-reported measure that asks questions about 21 categories of symptoms and functional limitations common to HNC. This article presents the development and usefulness of the ePVA as a clinical support tool for real-time interventions for patient-reported symptoms and functional limitations in HNC. Methods: Between January 2018 and August 2019, 75 participants were enrolled in a clinical usefulness study of the ePVA. Upon signing informed consent, participants completed the ePVA and the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ) general (C30) questionnaire v3.0 (scores range from 0 to 100 with 100 representing best HRQoL). Clinical usefulness of the ePVA was defined as demonstration of reliability, convergent validity with HRQoL, and acceptability of the ePVA (i.e., >70% of eligible participants complete the ePVA at two or more visits and >70% of ePVA reports are read by providers). Formal focus group discussions with the interdisciplinary teamthat cared for patients with HNC guided the development of the ePVA as a clinical support tool. Qualitative and quantitative methods were used throughout the study. Descriptive statistics consisting of means and frequencies, Pearson correlation coefficient, and Student’s t-tests were calculated using SAS 9.4 and STATA. Results: The participants were primarily male (71%), White (76%), diagnosed with oropharyngeal or oralcavity cancers (53%), and undergoing treatment for HNC (69%). Data analyses supported the reliability (alpha =0.85), convergent validity with HRQoL scores, and acceptability of the ePVA. Participants with the highest number of symptoms and functional limitations reported significantly worse HRQoL (sumof symptoms: r=–0.50, P<0.0001; sum of function limitations: r=–0.56, P<0.0001). Ninety-two percent of participants (59 of 64) who had follow-up visits within the 6-month study period completed the ePVA at twoor more visits and providers read 89% (169 of 189) of automated ePVA reports. The use of the ePVA as aclinical support tool for real-time interventions for symptoms and functional limitations reported by patients is described in a clinical exemplar. Conclusions: This research indicates that the ePVA may be a useful mHealth tool as a clinical support tool for real-time interventions for patient-reported symptoms and functional limitations in HNC. The study findings support future translational research to enhance the usefulness of the ePVA in real world settings for early interventions that decrease symptom burden and improve the QoL of patients with HNC
Impacts of extreme 2013–2014 winter conditions on Lake Michigan's fall heat content, surface temperature, and evaporation
Since the late 1990s, the Laurentian Great Lakes have experienced persistent low water levels and above average over‐lake evaporation rates. During the winter of 2013–2014, the lakes endured the most persistent, lowest temperatures and highest ice cover in recent history, fostering speculation that over‐lake evaporation rates might decrease and that water levels might rise. To address this speculation, we examined interseasonal relationships in Lake Michigan's thermal regime. We find pronounced relationships between winter conditions and subsequent fall heat content, modest relationships with fall surface temperature, but essentially no correlation with fall evaporation rates. Our findings suggest that the extreme winter conditions of 2013–2014 may have induced a shift in Lake Michigan's thermal regime and that this shift coincides with a recent (and ongoing) rise in Great Lakes water levels. If the shift persists, it could (assuming precipitation rates remain relatively constant) represent a return to thermal and hydrologic conditions not observed on Lake Michigan in over 15 years.Key PointsLake Michigan has been in an altered thermal regime since the late 1990sThe 2013–2014 winter may return Lake Michigan to pre‐1998 thermal conditionsHydrological impacts of the 2013–2014 cold winter remain unclearPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112001/1/grl52850.pd
Ultra-fast yttrium hydride chemistry at high pressures via non-equilibrium states induced by x-ray free electron laser
Controlling the formation and stoichiometric content of desired phases of
materials has become a central interest for the study of a variety of fields,
notably high temperature superconductivity under extreme pressures. The further
possibility of accessing metastable states by initiating reactions by x-ray
triggered mechanisms over ultra-short timescales is enabled with the
development of x-ray free electron lasers (XFEL). Utilizing the exceptionally
high brilliance x-ray pulses from the EuXFEL, we report the synthesis of a
previously unobserved yttrium hydride under high pressure, along with
non-stoichiometric changes in hydrogen content as probed at a repetition rate
of 4.5\,MHz using time-resolved x-ray diffraction. Exploiting non-equilibrium
pathways we synthesize and characterize a hydride with yttrium cations in an
\textit{A}15 structure type at 125\,GPa, predicted using crystal structure
searches, with a hydrogen content between 4.0--5.75 hydrogens per cation, that
is enthalpically metastable on the convex hull. We demonstrate a tailored
approach to changing hydrogen content using changes in x-ray fluence that is
not accessible using conventional synthesis methods, and reveals a new paradigm
in metastable chemical physics
Is the onset of disabling chronic conditions in later childhood associated with exposure to social disadvantage in earlier childhood? a prospective cohort study using the ONS Longitudinal Study for England and Wales
Background:
The aetiology of disabling chronic conditions in childhood in high income countries is not fully understood, particularly the association with socio-economic status (SES). Very few studies have used longitudinal datasets to examine whether exposure to social disadvantage in early childhood increases the risk of developing chronic conditions in later childhood. Here we examine this association, and its temporal ordering, with onset of all-cause disabling chronic later childhood in children reported as free from disability in early childhood.
Methods:
The study comprised a prospective cohort study, using data from the Office for National Statistics Longitudinal Study (ONSLS) for England and Wales. The study sample included 52,839 children with complete data born between 1981–1991 with no disabling chronic condition/s in 1991. Index cases were children with disability recorded in 2001. Comparison cases were children with no recorded disability in 1991. A socio-economic disadvantage index (SDI) was constructed from data on social class, housing tenure and car/van access. Associations were explored with logistic regression modelling controlling sequentially for potentially confounding factors; age, gender, ethnicity and lone parenthood.
Results:
By 2001, 2049 (4%) had at least one disability. Socio-economic disadvantage, age, gender and lone parenthood but not ethnicity were significantly associated with onset of disabling chronic conditions. The SDI showed a finely graded association with onset of disabling chronic conditions in the index group (most disadvantaged OR 2·11 [CI 1·76 to 2·53]; disadvantaged in two domains OR 1·45 [CI 1·20 to 1·75]; disadvantaged in one domain OR 1·14 [CI 0·93 to 1·39] that was unaffected by age, gender and ethnicity and slightly attenuated by lone parenthood.
Conclusion:
To our knowledge, this is the first study to identify socio-economic disadvantage in earlier childhood as a predisposing factor for onset of all-cause disabling chronic conditions in later childhood. Temporal ordering and gradation of the response indicate socio-economic disadvantage may play a causal role. This suggests that targeting preventative efforts to reduce socio-economic disadvantage in early childhood is likely to be an important public health strategy to decease health inequalities in later childhood and early adulthood
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