24 research outputs found
Experimental Study and Numerical Simulation of Sediment Transport in a Shallow Reservoir
The prediction of sedimentation is an important aspect of reservoir planning and design. Such prediction can be
supported by detailed analyses of flow patterns and sediment transport inside reservoirs, usually conducted through
numerical simulation. This research compares laboratorial sedimentation experiments in a shallow reservoir and
predictions using a 2D numerical model with depth-average Navier-Stokes equations and a sediment transport code.
A number of sediment transport equations were tested, among which the Engelund and FredsĂže formulation better
represented the measured data. Flows without sediment transport or without bed dunes could be simulated using
Smagorinskiâs turbulence model, while flows with sediment occurring over dunes needed the use of a constant
turbulent viscosity. The similarity obtained between experimental data and numerical results, for both flow pattern
and sediment deposition, confirms that the models and numerical codes used in this work are useful for the analysis
and prediction of reservoir sedimentation
Towards global consensus on core outcomes for hidradenitis suppurativa research: an update from the HISTORIC consensus meetings I and II
Background
A core outcomes set (COS) is an agreed minimum set of outcomes that should be measured and reported in all clinical trials for a specific condition. Hidradenitis suppurativa (HS) has no agreedâupon COS. A central aspect in the COS development process is to identify a set of candidate outcome domains from a long list of items. Our long list had been developed from patient interviews, a systematic review of the literature and a healthcare professional survey, and initial votes had been cast in two eâDelphi surveys. In this manuscript, we describe two inâperson consensus meetings of Delphi participants designed to ensure an inclusive approach to generation of domains from related items.
Objectives
To consider which items from a long list of candidate items to exclude and which to cluster into outcome domains.
Methods
The study used an international and multistakeholder approach, involving patients, dermatologists, surgeons, the pharmaceutical industry and medical regulators. The study format was a combination of formal presentations, small group work based on nominal group theory and a subsequent online confirmation survey.
Results
Fortyâone individuals from 13 countries and four continents participated. Nine items were excluded and there was consensus to propose seven domains: disease course, physical signs, HSâspecific quality of life, satisfaction, symptoms, pain and global assessments.
Conclusions
The HISTORIC consensus meetings I and II will be followed by further eâDelphi rounds to finalize the core domain set, building on the work of the inâperson consensus meetings
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
What causes hidradenitis suppurativa ?â15 years after
The 14 authors of the first review article on hidradenitis suppurativa (HS) pathogenesis published 2008 in EXPERIMENTAL DERMATOLOGY cumulating from the 1st International Hidradenitis Suppurativa Research Symposium held March 30âApril 2, 2006 in Dessau, Germany with 33 participants were prophetic when they wrote âHopefully, this heralds a welcome new tradition: to get to the molecular heart of HS pathogenesis, which can only be achieved by a renaissance of solid basic HS research, as the key to developing more effective HS therapy.â (Kurzen et al. What causes hidradenitis suppurativa? Exp Dermatol 2008;17:455). Fifteen years later, th
Effects of monovalent cations on the competitive adsorption of perfluoroalkyl acids by kaolinite: Experimental studies and modeling
Our hypothesis that longer-chained perfluoroalkyl acids (PFAAs) outcompete shorter-chained PFAAs during adsorption was tested in this study, wherein the adsorption interactions of six frequently detected PFAAs with kaolinite clay were modeled and examined experimentally using various suspension compositions. Competitive adsorption of PFAAs on the kaolinite surface was observed for the first time, and longer-chained PFAAs outcompeted those with a shorter chain. The electrostatic repulsion between adsorbed PFAA molecules is a primary inhibitory factor in PFAA adsorption. An increase in aqueous sodium or hydrogen ion concentration weakened electrostatic repulsions and changed the adsorption free energy. Therefore, the adsorption of a shorter-chained PFAA with weaker hydrophobicity could occur at high sodium or hydrogen ion concentrations. The experimental and modeling data suggest that the adsorption of shorter-chained PFAAs (â„4 perfluorinated carbons) in freshwater with a typical ionic strength of 10-2.5 is not thermodynamically favorable. Furthermore, by measuring the electrokinetic potential of kaolinite suspension in the presence of PFAAs, we found that the kaolinite surface became more negatively charged because of the adsorption of PFAAs. This observation indicates that the adsorbed PFAA molecules were within the electrical double layer of the kaolinite surface and that they contributed to the potential at the slipping plane. The possible alignments of adsorbed PFAA molecules on the kaolinite surface were then proposed. © 2011 American Chemical Society
Review of Highway Runoff Characteristics: Comparative Analysis and Universal Implications
This review interprets highway runoff characterization studies performed on different
continents. The results are synthesized to discuss the historical trends, first flush effects
of pollutants, pollutant form as dissolved vs. particulate, and to identify surrogate water
quality parameters. The information presented in this review showed that: (1) variability
has been observed in all quality parameters from each continent and among continents;
(2) with a few exceptions the variability seems to be within the expected range; (3)
inconsistent monitoring data as well as inconsistent quality assurance and quality control
measures were reported among studies, which may be partially responsible for variability
of water quality results; (4) compared with historic data, the concentration of total Pb
decreased exponentially, which can mostly be credited to leaded gasoline phase-out
regulation; (5) first flush effects of pollutants based on concentration have been reported
consistently (however, mass first flush effects for pollutants have been reported
inconsistently compared with concentration first flush effect); (6) most metal pollutants
and phosphorus are present in both the particulate and dissolved forms; and (7) strong
correlations were observed between TSS, TDS, TOC and iron (Fe) and 13 other constituents
and water quality parameters (turbidity, O&G, TPH, DOC, TKN, EC, Cl, Cd, Cr, Cu, Ni,
Pb, Zn)
Experimental studies on air entrainment and oxygen content downstream of sharp-crested weirs
Learning from New Product Development Projects : An Exploratory Study
Knowledge generation is a cornerstone of new product development and post-
projectreviews (PPRs) are widely recognized as a facilitator of project-to-
project learning.Empirical research on PPRs is sparse and so this paper
describes four in-depthexploratory case studies which look at how PPRs are
conducted and the learning thatcan result. The results indicate appropriately
managed PPRs can make a significantcontribution to knowledge generation and
exchange. In addition, the study indicates theurgent need for more research into
this important area
Learning from Post-project Reviews : A Cross-Case Analysis
Every new product development (NPD) project should not only deliver a successful
new product but also should generate learning for the organization. Postproject
reviews (PPRs) are recognized by both practitioners and academics as an
appropriate mechanism to stimulate and capture learning in NPD teams. However,
relatively few companies use PPRs, and those that do use them often fail to do
so effectively. Although they are widely perceived to be a useful tool,
empirical research on how PPRs are typically organized and the learning that
results is limited. The present article addresses this gap in the extant
knowledge and describes five in-depth case studies, which were conducted at
leading companies in Germany. A detailed investigation was made of how PPRs are
conducted and of the type of learning that can result. Three main sources of
data were used for each case: company documentation, in-depth interviews with
managers responsible for NPD, and observation of an actual PPR. The different
data sources enabled extensive triangulation of data to be conducted and a high
degree of reliability and validity to be achieved. The analysis enabled a number
of key characteristics of the way PPRs are managed to be identified. Various
characteristics of PPRs influence their utility, such as the time at which they
take place and the way discussions are moderated. In addition, the data show
that participants in the discussions at PPRs often use metaphors and stories,
which indicates that PPRs have the potential to generate tacit knowledge.
Interestingly, the data also show that there are various different ways in which
metaphors and stories appear to stimulate discussions on NPD projects. Based on
the cross-case analysis, a wide range of implications are identified.
Researchers need to investigate PPRs further to identify how they can generate
tacit and explicit knowledge and support project-to-project learning. The
generation of tacit knowledge in NPD is a topic that particularly needs further
investigation. The research also led to a range of recommendations for
practitioners. Companies need to strongly communicate the purpose and value of
PPRs, to run them effectively to stimulate the maximum possible learning, and to
disseminate the findings widely. PPRs have the potential to create and transfer
knowledge amongst NPD professionals, but, as they are seldom currently used,
many companies are missing an important opportunity