A comparison of plots for monothetic clustering, with applications to microbial communities and educational test development

Monothetic clustering for multivariate binary data provides a method of identifying variables whose levels identify the different patterns of responses. The default graphical summary of the standard version of this method provides information on the variables used to split the observations into groups and the proportions of the responses in the groups but not the levels of the responses in each cluster. A modified graph is proposed to provide fuller interpretations of the clustering results. The methods are applied to two examples and contrasted with other approaches to clustering multivariate binary responses. One application involves the clustering different bacterial clones presence/absence throughout distinct strata (or sections) in ice cores from Pony Lake, Antarctica, where the interest is in the full patterns of responses in the different clusters. The second is from a test developed to measure elementary education mathematics coaches knowledge of different aspects of mathematics coaching. In this second application, the interest lies more with questions that define distinct groups of individuals than with the entire pattern of responses

Basal conditions and glacier motion during the winter/spring transition, Worthington Glacier, Alaska, U.S.A.

Observations of the motion and basal conditions of Worthington Glacier, Alaska, U.S.A., during late-winter and spring melt seasons revealed no evidence of a relationship between water pressure and sliding velocity. Measurements included borehole water levels (used as a proxy for basal water pressure), surface velocity, englacial deformation, sliding velocity, and time-lapse videography of subglacial water flow and bed characteristics. The boreholes were spaced 10-15 m apart; six were instrumented in 1997, and five in 1998. In late winter, the water-pressure field showed spatially synchronous fluctuations with a diurnal cycle. The glacier\u27s motion was relatively slow and non-cyclic. In spring, the motion was characterized by rapid, diurnally varying sliding. The basal water pressure displayed no diurnal signal, but showed high-magnitude fluctuations and often strong gradients between holes. This transition in character of the basal water-pressure field may represent a seasonal evolution of the drainage system from linked cavities to a network of isolated patches and conduits. These changes occurred as the glacier was undergoing a season-velocity peak. The apparent lack of correlation between sliding velocity and water pressure suggests that local-scale water pressure does not directly control sliding during late winter or early in the melt season

Significance of trends toward earlier snowmelt runoff, Columbia and Missouri Basin headwaters, western United States

We assess changes in runoff timing over the last 55 years at 21 gages unaffected by human influences, in the headwaters of the Columbia-Missouri Rivers. Linear regression models and tests for significance that control for ‘‘false discoveries’’ of many tests, combined with a conceptual runoff response model, were used to examine the detailed structure of spring runoff timing. We conclude that only about one third of the gages exhibit significant trends with time but over half of the gages tested show significant relationships with discharge. Therefore, runoff timing is more significantly correlated with annual discharge than with time. This result differs from previous studies of runoff in the western USA that equate linear time trends to a response to global warming. Our results imply that predicting future snowmelt runoff in the northern Rockies will require linking climate mechanisms controlling precipitation, rather than projecting response to simple linear increases in temperature

Temperature effect on tert-butyl alcohol (TBA) biodegradation kinetics in hyporheic zone soils

<p>Abstract</p> <p>Background</p> <p>Remediation of tert-butyl alcohol (TBA) in subsurface waters should be taken into consideration at reformulated gasoline contaminated sites since it is a biodegradation intermediate of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-butyl formate (TBF). The effect of temperature on TBA biodegradation has not been not been published in the literature.</p> <p>Methods</p> <p>Biodegradation of [U ¹⁴C] TBA was determined using hyporheic zone soil microcosms.</p> <p>Results</p> <p>First order mineralization rate constants of TBA at 5°C, 15°C and 25°C were 7.84 ± 0.14 × 10^-3, 9.07 ± 0.09 × 10^-3, and 15.3 ± 0.3 × 10^-3days-1, respectively (or 2.86 ± 0.05, 3.31 ± 0.03, 5.60 ± 0.14 years^-1, respectively). Temperature had a statistically significant effect on the mineralization rates and was modelled using the Arrhenius equation with frequency factor (A) and activation energy (Ea) of 154 day^-1and 23,006 mol/J, respectively.</p> <p>Conclusion</p> <p>Results of this study are the first to determine mineralization rates of TBA for different temperatures. The kinetic rates determined in this study can be used in groundwater fate and transport modelling of TBA at the Ronan, MT site and provide an estimate for TBA removal at other similar shallow aquifer sites and hyporheic zones as a function of seasonal change in temperature.</p

Rationale and design of the Clinical Evaluation of Magnetic Resonance Imaging in Coronary heart disease 2 trial (CE-MARC 2): a prospective, multicenter, randomized trial of diagnostic strategies in suspected coronary heart disease

Background: A number of investigative strategies exist for the diagnosis of coronary heart disease (CHD). Despite the widespread availability of noninvasive imaging, invasive angiography is commonly used early in the diagnostic pathway. Consequently, approximately 60% of angiograms reveal no evidence of obstructive coronary disease. Reducing unnecessary angiography has potential financial savings and avoids exposing the patient to unnecessary risk. There are no large-scale comparative effectiveness trials of the different diagnostic strategies recommended in international guidelines and none that have evaluated the safety and efficacy of cardiovascular magnetic resonance.&lt;p&gt;&lt;/p&gt; Trial Design: CE-MARC 2 is a prospective, multicenter, 3-arm parallel group, randomized controlled trial of patients with suspected CHD (pretest likelihood 10%-90%) requiring further investigation. A total of 1,200 patients will be randomized on a 2:2:1 basis to receive 3.0-T cardiovascular magnetic resonance–guided care, single-photon emission computed tomography–guided care (according to American College of Cardiology/American Heart Association appropriate-use criteria), or National Institute for Health and Care Excellence guidelines–based management. The primary (efficacy) end point is the occurrence of unnecessary angiography as defined by a normal (&#62;0.8) invasive fractional flow reserve. Safety of each strategy will be assessed by 3-year major adverse cardiovascular event rates. Cost-effectiveness and health-related quality-of-life measures will be performed.&lt;p&gt;&lt;/p&gt; Conclusions: The CE-MARC 2 trial will provide comparative efficacy and safety evidence for 3 different strategies of investigating patients with suspected CHD, with the intension of reducing unnecessary invasive angiography rates. Evaluation of these management strategies has the potential to improve patient care, health-related quality of life, and the cost-effectiveness of CHD investigation

Shoot yield drives phosphorus use efficiency in Brassica oleracea and correlates with root architecture traits

The environmental and financial costs of using inorganic phosphate fertilizers to maintain crop yield and quality are high. Breeding crops that acquire and use phosphorus (P) more efficiently could reduce these costs. The variation in shoot P concentration (shoot-P) and various measures of P use efficiency (PUE) were quantified among 355 Brassica oleracea L. accessions, 74 current commercial cultivars, and 90 doubled haploid (DH) mapping lines from a reference genetic mapping population. Accessions were grown at two or more external P concentrations in glasshouse experiments; commercial and DH accessions were also grown in replicated field experiments. Within the substantial species-wide diversity observed for shoot-P and various measures of PUE in B. oleracea, current commercial cultivars have greater PUE than would be expected by chance. This may be a consequence of breeding for increased yield, which is a significant component of most measures of PUE, or early establishment. Root development and architecture correlate with PUE; in particular, lateral root number, length, and growth rate. Significant quantitative trait loci associated with shoot-P and PUE occur on chromosomes C3 and C7. These data provide information to initiate breeding programmes to improve PUE in B. oleracea

Experimental evidence of non-Amontons behaviour at a multicontact interface

We report on normal stress field measurements at the multicontact interface between a rough elastomeric film and a smooth glass sphere under normal load, using an original MEMS-based stress sensing device. These measurements are compared to Finite Elements Method calculations with boundary conditions obeying locally Amontons' rigid-plastic-like friction law with a uniform friction coefficient. In dry contact conditions, significant deviations are observed which decrease with increasing load. In lubricated conditions, the measured profile recovers almost perfectly the predicted profile. These results are interpreted as a consequence of the finite compliance of the multicontact interface, a mechanism which is not taken into account in Amontons' law

Impact of Lumacaftor/Ivacaftor on Pulmonary Exacerbation Rates in Members with Cystic Fibrosis in a Medicaid Population

This poster gives an overview of pulmonary exacerbation rates pre- and post-initiation of Lumacaftor/Ivacaftor (LUM/IVA) in Massachusetts\u27 Medicaid program. Pulmonary disease is one of the leading causes of morbidity and mortality among patients with cystic fibrosis. LUM/IVA has been effective in improving pulmonary outcomes in two observational studies, but before this study, there had been no published data evaluating real-world outcomes for Medicaid patients receiving this therapy. This poster on the impact of a drug for patients with cystic fibrosis was shared during the 2018 Academy of Managed Care Pharmacy Managed Care & Specialty Pharmacy Annual Meeting and awarded a gold ribbon. The poster abstracts were evaluated on relevance, originality, quality, bias and clarity. Only 20 percent of submitted abstracts were honored with awards

Elastic contact between self-affine surfaces: Comparison of numerical stress and contact correlation functions with analytic predictions

Contact between an elastic manifold and a rigid substrate with a self-affine fractal surface is reinvestigated with Green's function molecular dynamics. Stress and contact autocorrelation functions (ACFs) are found to decrease algebraically. A rationale is provided for the observed similarity in the exponents for stress and contact ACFs. Both exponents differ substantially from analytic predictions over the range of Hurst roughness exponents studied. The effect of increasing the range of interactions from a hard sphere repulsion to exponential decay is analyzed. Results for exponential interactions are accurately described by recent systematic corrections to Persson's contact mechanics theory. The relation between the area of simply connected contact patches and the normal force is also studied. Below a threshold size the contact area and force are consistent with Hertzian contact mechanics, while area and force are linearly related in larger contact patches.Comment: 12 pages, 9 figure

Validation of a vascular access specific quality of life measure (VASQoL)

Background: A self-administered 11 item vascular access specific quality of life measure (VASQoL) was previously derived from detailed qualitative interviews with adult patients with kidney failure who have experienced vascular access using the Capabilities Approach as a theoretical base. This study reports the psychometric validation of the VASQoL measure including its reliability, content validity and responsiveness to change. Methods: Cognitive interviews were conducted with 23 adult patients with kidney failure after completion of the VASQoL measure. Focus group discussion with a vascular access professional multidisciplinary team was undertaken (n = 8) and subsequently a further 101 adult kidney failure patients with vascular access (TCVC, AVF or AVG) completed the digital VASQoL measure, EQ-5D and SF-36 questionnaires in a longitudinal study with prospectively recorded vascular access events. Results: Transcript analysis of cognitive interviews after VASQoL completion indicated that the content was comprehensive and well understood by participants. Assessment of Internal reliability for the VASQoL measure was high (Cronbach’s alpha 0.858). Test-retest reliability of the overall VASQoL measure was high (intra class correlation coefficient 0.916). In those patients who experienced a vascular access event, significant differences were observed in paired analysis of the VASQoL physical domain questions and vascular access function domain questions and in the EQ-5D usual activities, pain and anxiety domains. In those with no vascular access event, variation was observed in longitudinal analysis in VASQoL questions relating to worry about VA function and capability domains, whilst no variation was observed in the EQ5D measure. Conclusion: The VASQoL measure has good internal consistency, test-retest reliability, convergent validity and responsiveness to change for clinically relevant vascular access outcomes. This provides a validated, vascular access specific quality of life measure that can be used in future trials of vascular access, evaluation of new technologies and routine use as a patient reported outcome measure (PROM)