270 research outputs found
The ResQu Index: A new instrument to appraise the quality of research on birth place
© 2017 Vedam et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Objective: Place of birth is a known determinant of health care outcomes, interventions and costs. Many studies have examined the maternal and perinatal outcomes when women plan to give birth in hospitals compared with births in birth centres or at home. However, these studies vary substantially in rigour; assessing their quality is challenging. Existing research appraisal tools do not always capture important elements of study design that are critical when comparing outcomes by planned place of birth. To address this deficiency, we aimed to develop a reliable instrument to rate the quality of primary research on maternal and newborn outcomes by place of birth. Study design: The instrument development process involved five phases: 1) generation of items and a weighted scoring system; 2) content validation via a quantitative survey and a modified Delphi process with an international, multi-disciplinary panel of experts; 3) inter-rater consistency; 4) alignment with established research appraisal tools; and 5) pilot-testing of instrument usability. Results: A Birth Place Research Quality Index (ResQu Index) was developed comprising 27 scored items that are summed to generate a weighted composite score out of 100 for studies comparing planned place of birth. Scale content validation indices were .89 for clarity, .94 for relevance and .90 for importance. The Index demonstrated substantial inter-rater consistency; pilot-testing confirmed feasibility and user-friendliness. Conclusion: The ResQu Index is a reliable instrument to evaluate the quality of design, methods and interpretation of reported outcomes from research about place of birth. Higher-scoring studies have greater potential to inform evidence-based selection of birth place by clinicians, policy makers, and women and their families. The Index can also guide the design of future research on place of birth
Measuring respect and autonomy in Dutch maternity care:Applicability of two measures
Problem: In the Netherlands there are no valid measurement tools available to measure respectful maternity care and women's autonomy. Background: Respectful maternity care including women's autonomy during childbirth are key components of high quality care. Aim: This study aims to evaluate the applicability of the Canadian measures; the Mothers Autonomy in Decision Making (MADM) scale and the Mothers on Respect index (MORi) measures among pregnant women in the Netherlands. Methods: We translated the measures MORi and MADM according to the WHO guidelines, adapted them to the Dutch health care system, evaluated their psychometric properties, and pilot tested before administration through an online cross-sectional survey. We assessed feasibility by calculating descriptive statistics on scores, and reliability by calculating Cronbach's alpha. The construct validity was measured by hypotheses on differences between subgroups based on maternal characteristics, pregnancy characteristics and healthcare provision. Findings: Of 557 women included in the study, 83% experienced high respect and 62% experienced high autonomy. Both the MORi and MADM showed feasibility, internal consistency, and with respect to construct validity, both measures discriminated between type of care provision. Compared to women with pregnancy complications, those with a healthy pregnancy reported statistically higher MORi-scores. No differences were observed on MADM-scores. Discussion: Both instruments can be used as quality of care measures aiming to improve care and thus experiences of women. Conclusion: The results of this study support the feasibility, reliability, and to a certain extent known group validity of the Dutch MORi and MADM measures in pregnant women
Photoelasticity of crystalline and amorphous silica from first principles
Based on density-functional perturbation theory we have computed from first
principles the photoelastic tensor of few crystalline phases of silica at
normal conditions and high pressure (quartz, -cristobalite,
-cristobalite) and of models of amorphous silica (containig up to 162
atoms), obtained by quenching from the melt in combined classical and
Car-Parrinello molecular dynamics simulations. The computational framework has
also been checked on the photoelastic tensor of crystalline silicon and MgO as
prototypes of covalent and ionic systems. The agreement with available
experimental data is good.
A phenomenological model suitable to describe the photoelastic properties of
different silica polymorphs is devised by fitting on the ab-initio data.Comment: ten figure
The Canadian birth place study: examining maternity care provider attitudes and interprofessional conflict around planned home birth
Maternal and perinatal outcomes by planned place of birth among women with low-risk pregnancies in high-income countries: A systematic review and meta-analysis
© 2018 The Author(s) Background: The comparative safety of different birth settings is widely debated. Comparing research across high-income countries is complex, given differences in maternity service provision, data discrepancies, and varying research techniques and quality. Studies of births planned at home or in birth centres have reported both better and poorer outcomes than planned hospital births. Previous systematic reviews have focused on outcomes from either birth centres or home births, with inconsistent attention to quality appraisal. Few have attempted to synthesise findings. Objective: To compare maternal and perinatal outcomes from different places of birth via a systematic review of high-quality research, and meta-analysis of appropriate data (Prospero registration CRD42016042291). Design: Reviewers searched CINAHL, Embase, Maternity and Infant Care, Medline and PsycINFO databases to identify studies comparing selected outcomes by place of birth among women with low-risk pregnancies in high-income countries. They critically appraised identified studies using an instrument specific to birth place research and then combined outcome data via meta-analysis, using RevMan software. Findings: Twenty-eight articles met inclusion criteria, yielding comparative data on perinatal mortality, mode of birth, maternal morbidity and/or NICU admissions. Meta-analysis indicated that women planning hospital births had statistically significantly lower odds of normal vaginal birth than in other planned settings. Women experienced severe perineal trauma or haemorrhage at a lower rate in planned home births than in obstetric units. There were no statistically significant differences in infant mortality by planned place of birth, although most studies had limited statistical power to detect differences for rare outcomes. Differences in location, context, quality and design of identified studies render results subject to variation. Conclusions and implications for practice: High-quality evidence about low-risk pregnancies indicates that place of birth had no statistically significant impact on infant mortality. The lower odds of maternal morbidity and obstetric intervention support the expansion of birth centre and home birth options for women with low-risk pregnancies
PCA-based lung motion model
Organ motion induced by respiration may cause clinically significant
targeting errors and greatly degrade the effectiveness of conformal
radiotherapy. It is therefore crucial to be able to model respiratory motion
accurately. A recently proposed lung motion model based on principal component
analysis (PCA) has been shown to be promising on a few patients. However, there
is still a need to understand the underlying reason why it works. In this
paper, we present a much deeper and detailed analysis of the PCA-based lung
motion model. We provide the theoretical justification of the effectiveness of
PCA in modeling lung motion. We also prove that under certain conditions, the
PCA motion model is equivalent to 5D motion model, which is based on physiology
and anatomy of the lung. The modeling power of PCA model was tested on clinical
data and the average 3D error was found to be below 1 mm.Comment: 4 pages, 1 figure. submitted to International Conference on the use
of Computers in Radiation Therapy 201
A proposed framework for consensus-based lung tumour volume auto-segmentation in 4D computed tomography imaging.
This work aims to propose and validate a framework for tumour volume auto-segmentation based on ground-truth estimates derived from multi-physician input contours to expedite 4D-CT based lung tumour volume delineation. 4D-CT datasets of ten non-small cell lung cancer (NSCLC) patients were manually segmented by 6 physicians. Multi-expert ground truth (GT) estimates were constructed using the STAPLE algorithm for the gross tumour volume (GTV) on all respiratory phases. Next, using a deformable model-based method, multi-expert GT on each individual phase of the 4D-CT dataset was propagated to all other phases providing auto-segmented GTVs and motion encompassing internal gross target volumes (IGTVs) based on GT estimates (STAPLE) from each respiratory phase of the 4D-CT dataset. Accuracy assessment of auto-segmentation employed graph cuts for 3D-shape reconstruction and point-set registration-based analysis yielding volumetric and distance-based measures. STAPLE-based auto-segmented GTV accuracy ranged from (81.51  ±  1.92) to (97.27  ±  0.28)% volumetric overlap of the estimated ground truth. IGTV auto-segmentation showed significantly improved accuracies with reduced variance for all patients ranging from 90.87 to 98.57% volumetric overlap of the ground truth volume. Additional metrics supported these observations with statistical significance. Accuracy of auto-segmentation was shown to be largely independent of selection of the initial propagation phase. IGTV construction based on auto-segmented GTVs within the 4D-CT dataset provided accurate and reliable target volumes compared to manual segmentation-based GT estimates. While inter-/intra-observer effects were largely mitigated, the proposed segmentation workflow is more complex than that of current clinical practice and requires further development
Ameloblastic Fibroodontoma: Uncommon Case Presentation in a 6-Year-Old Child with Review of the Literature
Ameloblastic fibroodontoma is a benign mixed odontogenic neoplasm considered in patients with asymptomatic swelling and unerupted teeth that exhibit histologic features between ameloblastic fibroma and complex odontoma. Radiographically, this lesion appears as radiolucency admixed with focal radio opaque masses of irregular shapes and sizes. This lesion is confirmed by the presence of proliferating odontogenic epithelium, ectomesenchyme, and dental hard tissue formation on pathological analysis supplementing clinical and radiographic findings. As this tumour is less commonly seen in routine clinical practice, ameloblastic fibroodontoma with detailed orofacial features and periodic approach to its diagnosis is discussed. This paper reports a case of ameloblastic fibroodontoma of the mandible in a 6-year-old male patient with an uncommon case presentation and review of the literature
A systematic review to examine the evidence regarding discussions by midwives, with women, around their options for where to give birth
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