Multilevel Comparison Research Articles

The Role of “Opportunity to Learn” in the Geometry Curriculum: A Multilevel Comparison of Six Countries

In international comparisons for mathematics in PISA and TIMSS, Asia outperforms England considerably at secondary level. For geometry this difference is even greater. With a new maths curriculum having come into play in England in 2014, and hence the need to explore the impact of the curriculum on student achievement, this article focuses on how differences in achievement might be attributed to differences in ‘opportunity to learn’ within a country’s curriculum. The aims of this paper are two-fold. Firstly we want to provide an integrated conceptual framework that combines elements from educational effectiveness, a curriculum model and ‘opportunity to learn’ for analysing curriculum effects, which we call the Dynamic Opportunities in the Curriculum (DOC) framework. Secondly, using multilevel models, we empirically investigate with TIMSS 2011 data whether the ‘opportunity to learn’ in the curriculum is associated with achievement in geometry education in six countries, thus validating that model. The results show that our conceptualisation of ‘opportunity to learn’ can be useful in analysing curriculum effects.

ПРО ВПЛИВ ШЕВЧЕНКОВОЇ АВТОБІОГРАФІЇ НА КУЛІШЕВУ

In honor of the 200th anniversary of P. Kulish's birth, the article offers a multi-level comparison of autobiographies of two prominent Ukrainian writers of the 19th century. In the categories and concepts of modern literary criticism, the hypothesis of literary influence of T. Shevchenko on P. Kulish's perception of artistic autobiography genre is checked and confirmed. For this purpose, three texts are compared: an autograph of "Autobiography" by T. Shevchenko, deeply edited by P. Kulish for printing in "People's Reading" journal, a version of T. Shevchenko's "Autobiography" and an autobiography "My Life" by P. Kulish. The comparison is carried out at narratological, compositional, genre and intertextual levels. The historical background of the creation of each of the texts is analyzed. It is proved that the autograph of T. Shevchenko's "Autobiography" and P. Kulish's "My Life" both belong to the genre of artistic autobiography and have a compressed narrative structure. It is confirmed that T. Shevchenko didn't have extra-literary reasons for creating a third-person autobiography, unlike P. Kulish, who, moreover, was very likely to come under the literary influence of the text of T. Shevchenko and developed T. Shevchenko's narrative structure in his artistic autobiography. At the same time, it is assumed that literary influence might not be the main argument in choosing a third-person narration, since there were extra-literary reasons for keeping P. Kulish's incognito. It is noted that the text "My Life" of P. Kulish is more functional in the aspects of orientation to objectivity, emotional pressure and moderation of the author's image in literary life. Its narrative structure is compressed precisely for the sake of objectivity, addressees and consignees are implicit and difficult to isolate on each of the layers of the narrative structure precisely to mimic the non-fiction. The text of a letter to the author integrated into "My Life" is the only exception. It is concluded that hypothesis about literary influence of T. Shevchenko on P. Kulish within the genre of artistic autobiography is reliable and well-reasoned. To the author's mind, further studies should focus on finding evidence of unconscious literary influence of T. Shevchenko on P. Kulish in other genres, chances of discovering which in future are rather high.

Multilevel comparison between magnetite and quartzite as thermocline energy storage materials

This paper presents a multilevel comparison between two thermal energy storage materials: quartzite as the most known thermocline energy storage material and magnetite as a new potential candidate. This comparison involves: thermal and thermophysical properties, cycling effect and thermocline thermal energy storage performances. In first, an experimental characterization of magnetite under cycling has been performed, and then magnetite was compared to quartzite from this viewpoint. It has been demonstrated that for the medium temperature range (i.e. from 100 °C to 500 °C), thermal cycling has a positive impact on magnetite characteristics and performances. Thereafter, a numerical model for thermocline storage has been presented and validated. Then, the thermocline behavior and the thermal energy storage performances of both materials during charging and discharging processes have been investigated and tested for various heat transfer fluidscommonly used, including natural oil, synthetic oils and molten salts. This study shows that, for the different HTF tested, no significant difference between the thermocline zone thicknesses can be noted between the two TESM. It has been concluded that for the same storage tank size and the same discharge time, magnetite can store and restore more energy and requires less storage volume although quartzite presents higher efficiencies. For magnetite, this can represent an advantage from an economic and technical standpoint. While for the same storage tank size and the same HTF speed, the magnetite charges and discharges more slowly. On the other hand, the different combinations HTF/TESM tested show that thermocline performances are driven by not only the filler material but also the nature of the heat transfer fluid. In that sense, the molten salt fluids arelargely more efficient for both TESMs than other fluids.

Multilevel analysis of dendroclimatic series with the R-package BIOdry.

The R-package BIOdry allows to model and compare fluctuations of Tree-ring Width (TRW) and climate, or dendroclimatic fluctuations, while accounting for source variability. The package eases multilevel modeling and multivariate comparison in dendroclimatic analysis using the nlme and ecodist packages, respectively. For implementing such libraries, the in-package algorithms transform the dendroclimatic fluctuations into Multilevel Dendroclimatic Data Series and maintain categorical variables and time units in the outputs. The dendroclimatic modeling is developed with two functions: modelFrame and muleMan. The first function binds core-level cumulative TRWs to the processed data sets and subtracts trends in TRWs by fitting multilevel log-linear growth formulas or multilevel linear formulas. modelFrame can also model within-group fluctuations in dendroclimatic variables other than tree-radial increments such as aridity indices or allometric components of tree growth: e.g. diameters at breast height over bark, tree basal areas, total tree biomass, among other. The second function compares fluctuations in modelFrame objects that share outermost categorical variable and annual records. Here, we use BIOdry to model dendroclimatic relationships in northern and east-central Spain to illustrate future users in the implementation of the package for modeling ecological relationships in space and time.

Risk choice and emotional experience: a multi-level comparison between active and passive decision-making

Previous studies have consistently indicated the important role of emotional experience in decision-making. While both active and passive decision-making coexist in our daily lives, whether and how active and passive decision-making induce different emotional experience remains unclear. In the present research we conduct three studies to examine differences in emotional experience associated with active and passive decisions at multiple levels. First, at the individual level, using both active and passive modes of the Balloon Analog Risk Task in a laboratory behavior study, we demonstrate that active decision-making is associated with more positive emotional experience compared to passive decision-making, including more happiness, less distress, a greater sense of control, and a stronger sense of achievement. Second, at the neural level, we use functional magnetic resonance imaging and find greater activation in the brain’s emotional circuits during active decisions compared to passive decisions, regardless of the decision outcomes. Finally, at the population level, we conduct a large-scale survey to capture the perception of emotional experience during real-world active and passive decisions, and our results confirm that active decisions engender a greater sense of achievement and sense of control and people prefer active decisions to passive decisions. These findings provide valuable insights into the role of emotion experience in decision-making research and practices.

Mathematical model comparing of the multi-level economics systems

The mathematical model (scheme) of a multi-level comparison of the economic system, characterized by the system of indices, is worked out. In the mathematical model of the multi-level comparison of the economic systems, the indicators of peer review and forecasting of the economic system under consideration can be used. The model can take into account the uncertainty in the estimated values of the parameters or expert estimations. The model uses the multi-criteria approach based on the Pareto solutions.

Farm Gate Prices for Non-Varietal Wine in Argentina: A Multilevel Comparison of the Prices Paid by Cooperatives and Investor-Oriented Firms

Abstract In this paper, we use a unique data set of the prices paid to farmers in Argentina for grapes to examine the prices paid by non-varietal wine processing cooperatives and investor-oriented firms (IOFs). Motivated by contrasting theoretical predictions of cooperative price effects generated by the yardstick of competition and property rights theories, we apply a multilevel regression model to identify price differences at the transaction level and the departmental level. On average, farmers selling to cooperatives receive a 3.4 % lower price than farmers selling to IOFs. However, we find cooperatives pay approximately 2.4 % more in departments where cooperatives have larger market shares. We suggest that the inability of cooperatives to pay a price equal to or greater than the one paid by IOFs can be explained by the market structure for non-varietal wine in Argentina. Specifically, there is evidence that cooperative members differ from other farmers in terms of size, assets and the cost of accessing the market. We conclude that the analysis of cooperative pricing cannot solely focus on the price differential between cooperatives and IOFs, but instead must consider other factors that are important to the members.

Financing entrepreneurship by risk capital - evidence revisited

This paper summarises the large body of literature dedicated to risk capital within entrepreneurship. This work attempts to advance this field of research and identifies crucial research prospects by examining and evaluating the current body of literature by means of a literature review using a qualitative and quantitative approach. Multi-level comparisons of previous discussions and studies on the perspectives of different market participants reveal gaps that warrant further critical debate. Having synthesised the existing body of literature, the paper concludes by proposing three essential directions for the future while calling for stronger (theoretical) ties between the finance and entrepreneurship literature.

A multi-level comparative analysis of human femoral cortical bone quality in healthy cadavers and surgical safe margin of osteosarcoma patients

Osteosarcoma is the most common primary malignancy of bone. However, the potential variation it brings to the adjacent undamaged bone tissue is seldom investigated. In this study, we conducted a multi-level comparison of human femoral cortical bone quality in healthy cadavers (aged 42±11 years) and in resected safe margin of osteosarcoma patients (aged 49±15 years). The objective of this study was to document the changes with exposure to osteosarcoma condition in bone mechanical strength, structural morphology and elementary composition, evaluated by static and dynamic mechanical analysis (DMA), scanning electron microscopy (SEM) imaging, X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The resected clinical samples from healthy and osteosarcoma conditioned bones were grouped into the Tumor and Healthy groups, and shaped into regular beam specimens or pulverized according to testing protocols. The results of mechanical tests confirmed osteolytic deteriorations in mineral phase of the Tumor group, in terms of significant reductions in storage modulus (−53.6%, at 1Hz), bending strength (−53.0%) and stiffness (−64.8%) as compared to the Healthy group. However, the energy dissipation/absorption ability of the collagen phase in the Tumor group did not differ from the Healthy group statistically. Although specimens showed no visible morphological difference, a decline in osteocyte lacunar density in bone specimens from the Tumor group was discovered (−54.4%, p<0.001). Higher magnification observation showed that the cell-free lacunae in the Tumor group were occluded by randomized overgrown collagen fibers. XRD and FTIR analysis further demonstrated a lower hydroxyapatite crystallinity and decreased mineral:matrix ratio in pulverized samples from the Tumor group, mainly due to the prominent Amide peaks. Taken together, these data revealed a previously unrecognized effect of osteosarcoma on the adjacent “normal” bone quality. The current study may provide insights on bone tumor pathology and an advanced understanding of surgical safe margin.

Abstract 688: Identifying TMEM106B as a novel metastasis driver in non-small cell lung cancers through an in vivo gain-of-function screen

Abstract Metastatic lung cancer is the leading cause of cancer related death in the world and novel approaches are necessary to elucidate specific genes that drive lung cancer progression and metastasis. Lung cancers commonly demonstrate genetic alteration of potent drivers like Kras, p53 or EGFR accompanied with hundreds of low frequency gene aberrations which are a mix of key driver events and nascent passenger mutations. We established a robust screening platform to selectively identify these functionally critical “driver” genes in lung cancers from a prioritized list of candidates selected by a multi-level cross-species comparison of our published high confidence transcriptome data from genetically-engineered mouse models and genomic data of human lung cancers from TCGA, focusing on elevated gene expression and/or gene amplification. We identified 225 putative candidate driver genes which were used to construct a lentiviral based cDNA expression library with unique molecular barcoding of individual cDNAs. Using a non-metastatic syngeneic mouse lung cancer model we generated individually transduced stable over-expressing lines for each gene. These candidate lines were used for a unique in vivo positive selection screen to identify functional metastasis drivers. We transplanted pools of 20 cDNA expressing lines into syngeneic mice and observed for primary tumor growth and occurrence of metastases in lungs and other organs. Metastatic drivers were identified by the relative enrichment of the unique barcode sequences in the genomic DNA from metastatic lesions over primary tumors. We have identified both known (e.g. MYC) and several novel (e.g. THRA, TMEM106B, GNAS) potential oncogenic and metastatic drivers. We validated our top hits for their individual in vivo metastatic potencies by gain-of-function/loss-of-function studies and identified TMEM106B as one of the primary drivers of metastasis. TMEM106B is a transmembrane protein localizing to the lysosomes and has been shown to drive expression of lysosomal genes. We hypothesize that elevated levels of TMEM106B is able to drive the expression and secretion of lysosomal enzymes thus making cancer cells hyper invasive and metastatic. We found strong correlation for expression of TMEM106B with several lysosomal genes in a panel of 1016 human lung cancers and are currently performing in depth studies to understand these mechanisms of TMEM106B driven metastasis. We are also analyzing the clinical relevance of TMEM106B based upon their expression pattern and prognostic utility across TCGA and other public datasets, along with in-house patient samples and tissue microarrays of resected and biopsy specimens. Identification of such novel players will significantly advance the field of cancer target discovery by identifying new drug targets and biomarkers, essential for effective treatment options for lung cancer patients. Citation Format: Samrat Kundu, Caitlin Grzeskowiak, Chad J. Creighton, Kenneth L. Scott, Don L. Gibbons. Identifying TMEM106B as a novel metastasis driver in non-small cell lung cancers through an in vivo gain-of-function screen. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 688.

Abstract B25: A novel in vivo gain-of-function screen for metastasis drivers in non-small cell lung cancers

Abstract Metastatic lung cancer is the leading cause of cancer related mortality in the world. Insights on specific genetic causes are limited and novel approaches are necessary to elucidate specific genes that drive lung cancer progression and metastasis. Extensive genomic and transcriptomic profiling of human lung cancers by consortia like ‘The Cancer Genome Atlas’ (TCGA) and the ‘International Cancer Genome Consortium’ (ICGC) has revealed a complex genetic landscape marked by abundant aberrations. In addition to acquiring mutations or amplification of well documented drivers like Kras, p53 or EGFR, lung cancers also demonstrate an enrichment of hundreds of low frequency gene aberrations which are a mix of key driver mutations and nascent passenger alterations caused by progressive genomic instability that could have definite role in cancer progression and metastasis. Our goal was to establish a robust screening platform to selectively identify these functionally critical “driver” genes in lung cancers. To identify a prioritized list of potential candidates we performed a multi-level cross-species comparison of our published high confidence transcriptome data from genetically-engineered mouse models of lung cancers and human lung cancer genomic data from TCGA, focusing on elevated gene expression and/or gene amplification. We identified an enriched list of 225 putative driver genes in lung cancers which were used to construct a lentiviral based cDNA expression library with unique molecular barcoding of individual cDNAs. Using a non-metastatic syngeneic mouse lung cancer model we generated individually transduced stable over-expressing lines for each of the 225 genes. These candidate lines were then entered into parallel in vitro and in vivo screens. In vitro testing includes cell invasion assays in a 96-well format, with positive hits defined as those scoring above 3x standard deviations relative to the control cells expressing mCherry. Positive hits were revalidated using standard 24-well invasion assays and also studied for growth phenotypes in 3D cultures. To selectively identify genes with functional role in metastasis, we performed a unique in vivo positive selection screen to test individual and combinatorial effects of lung cancer driver aberrations. For this we used pools of 20 cDNA expressing lines transplanted into syngeneic mice and observed for primary tumor growth and occurrence of metastases in lungs and other organs. Metastatic lesions and primary tumors were collected and genomic DNA from these was used to identify the unique individual barcodes by NGS barcode enrichment analysis. Metastatic drivers were identified by the relative enrichment of the unique barcode sequences for all the respective pool cDNAs in the metastatic tissue. We have identified both known (e.g. MYC) and several novel (e.g. THRA, TMEM106B, GNAS) potential oncogenic and metastatic drivers from the pooled screen which are currently being revalidated for their individual in vivo metastatic potencies. We are performing gain-of-function/loss-of-function studies for the identified driver genes to determine the pathways which they regulate. We are also analyzing the clinical relevance of these genes based upon their expression pattern and prognostic utility across TCGA and other public datasets, along with in-house patient samples and tissue microarrays of resected and biopsy specimens. Our unique high through-put approach will significantly advance the field of cancer target discovery by identifying new drug targets and biomarkers, essential for novel effective treatment options for lung cancer patients. Citation Format: Samrat T. Kundu, Caitlin Grzeskowiak, Chad J. Creighton, Kenneth L. Scott, Don L. Gibbons. A novel in vivo gain-of-function screen for metastasis drivers in non-small cell lung cancers. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Metastasis; 2015 Nov 30-Dec 3; Austin, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(7 Suppl):Abstract nr B25.

Did the notochord evolve from an ancient axial muscle? The axochord hypothesis.

The origin of the notochord is one of the key remaining mysteries of our evolutionary ancestry. Here, we present a multi‐level comparison of the chordate notochord to the axochord, a paired axial muscle spanning the ventral midline of annelid worms and other invertebrates. At the cellular level, comparative molecular profiling in the marine annelids P. dumerilii and C. teleta reveals expression of similar, specific gene sets in presumptive axochordal and notochordal cells. These cells also occupy corresponding positions in a conserved anatomical topology and undergo similar morphogenetic movements. At the organ level, a detailed comparison of bilaterian musculatures reveals that most phyla form axochord‐like muscles, suggesting that such a muscle was already present in urbilaterian ancestors. Integrating comparative evidence at the cell and organ level, we propose that the notochord evolved by modification of a ventromedian muscle followed by the assembly of an axial complex supporting swimming in vertebrate ancestors.

Multilevel comparison of large urban systems

For the first time the systems of cities in seven countries or regions among the largest in the world (China, India, Brazil, Europe, the Former Soviet Union (FSU), the United States and South Africa) are made comparable through the building of spatio-temporal standardised statistical databases. We first explain the concept of a generic evolutionary urban unit ("city") and its necessary adaptations to the information provided by each national statistical system. Second, the hierarchical structure and the urban growth process are compared at macro-scale for the seven countries with reference to Zipf's and Gibrat's model: in agreement with an evolutionary theory of urban systems, large similarities shape the hierarchical structure and growth processes in BRICS countries as well as in Europe and United States, despite their positions at different stages in the urban transition that explain some structural peculiarities. Third, the individual trajectories of some 10,000 cities are mapped at micro-scale following a cluster analysis of their evolution over the last fifty years. A few common principles extracted from the evolutionary theory of urban systems can explain the diversity of these trajectories, including a specific pattern in their geographical repartition in the Chinese case. We conclude that the observations at macro-level when summarized as stylised facts can help in designing simulation models of urban systems whereas the urban trajectories identified at micro-level are consistent enough for constituting the basis of plausible future population projections.

Assessment of work intensification by managers and psychological distressed and non-distressed employees: a multilevel comparison.

Work intensification is a popular management strategy to increase productivity, but at the possible expense of employee mental stress. This study examines associations between ratings of work intensification and psychological distress, and the level of agreement between compared employee-rated and manager-rated work intensification. Multi-source survey data were collected from 3,064 employees and 573 company managers from the private sector in 2010. Multilevel regression models were used to compare different work intensification ratings across psychological distress strata. Distressed employees rated higher degree of total work intensification compared to non-distressed employees, and on three out of five sub ratings there were an increased prevalence of work intensification in the case group. In general, there was poor agreement between employee and company work intensification rating. Neither manager-rated work intensification nor employee/manager discrepancy in work intensification ratings was associated with psychological distress. Distressed employees had a higher total score of employee/manager agreed work intensification, and a higher prevalence of increased demands of labour productivity. This study demonstrates higher ratings of employee/manager agreed work intensification in distressed employees compared to non-distressed employees, challenging previous findings of reporting bias in distressed employees’ assessment of work environment.

Both Sides of the Story

While digital networked media contribute to a substantial shift in the relationship between journalists and their audiences, current research still largely focuses on one side or the other. This paper aims to overcome this conceptual and empirical deficit by presenting findings from two case studies on German news journalism (a daily TV newscast and a weekly political talk show). They operationalize the concept of inclusion distance, which aims at the (in-)congruence of mutual expectations between journalists and audience members, in a series of standardized surveys among newsroom staff as well as their online users. The paper introduces three different comparative dimensions which this study design affords and illustrates them with findings (1) on journalistic role conceptions and (2) the (assumed) motivations for participation. Besides demonstrating the value of such a multi-level comparison, our findings also provide substantial and nuanced evidence concerning the relation between journalists and their audiences: in both cases we find high congruence regarding the importance of traditional journalistic tasks such as objective reporting on complex issues, while the inclusion distance is larger for tasks connected to new participatory practices such as opportunities for user-generated content. Regarding motivations for participation, we find a somewhat larger inclusion distance as journalists of both newsrooms overestimate emotional or self-directed goals, but underestimate the wish for expanding knowledge as reasons why users participate.

Diverse Workplaces and Interethnic Friendship Formation—A Multilevel Comparison across 21 OECD Countries

We study how workplace diversity affects how native-born populations form interethnic friendship relations. Drawing on network elasticity research, the relationship between functional and cognitive interdependencies, and intergroup contact theory, we argue that diverse workplaces—because they restrict individuals' opportunities to act on tendencies towards homophily more than other social units—have a particularly strong potential for integration. We test our argument by analysing data from the first round of the European Social Survey with multilevel modelling. In line with expectations, we find that individuals who work at diverse workplaces are more likely than individuals who work at homogenous workplaces to have immigrant friends; that workplace diversity is more efficacious than neighbourhood diversity in generating interethnic friendship relations; and that the association between workplace diversity and the likelihood of having immigrant friends is stronger among individuals who have a low level of education, feel economically vulnerable, and who live in countries characterized by relative resource scarcity.

Inter-organizational design fit in inter-organizational knowledge management

The purpose of this paper is to analyze existing knowledge on how organizations learn using multilevel comparison perspective of intra- and inter-organizational learning and to offer deeper understanding of the role that organizational design properties have in inter-organizational learning. Using Argote and Ophir (2005) findings on similarity vs complementarity fit developed for intra-organizational learning as an anchor, we analyze the role similarity vs complementarity fit of organizational configuration and coordination properties in inter-organizational settings. Our intention is to explicitly express the role of interorganizational design fit in inter-organizational knowledge management. Framework developed here systematizes and explains how strategic objectives of network creation (exploration or exploitation) should be aligned with learning mechanisms (learning by doing or learning by listening/observing) and organizational design properties. From the point of organization theory, this paper advances knowledge about the influence organizational design as intra-organizational property has on knowledge transfer between organizations and inter-organizational learning. Our framework helps managers understand how inter-organizational design fit can influence inter-organizational learning within the network. With regard to policy making, knowledge networks are becoming increasingly important as a mechanism of industrial development support, economic growth, increase of employment and poverty reduction and this paper points to mechanisms of inter-organizational design that can be used in managing these networks.

Global Impact of Heparin on Gene Expression Profiles in Neural Cells Infected by Enterovirus 71

Objectives: Heparan sulphate mimetics, particularly heparin (Hep), have previously been shown to considerably inhibit infection of enterovirus 71 (EV71) in Vero cells. Therefore, in this study, a genome-wide DNA microarray was performed to gain insight into the mechanism(s) of action of Hep against infection of a human neural cell line, SK-N-SH, with a clinical strain of EV71. Methods: This study focused on a selection of EV71-induced genes whose expression profiling was exclusively affected by the antiviral activity of Hep. The selection procedure was performed through a statistical multi-level comparison with the following controls: negative control cells, compound control (cells treated with Hep only), virus control (cells treated with virus only) and treatment control (EV71-infected cells treated with Hep). Results: Overall, of more than 30,000 genes studied, 14 well-known annotated genes were selected that may be targets for the antiviral activity of Hep against EV71 infection in neural cells. For most of these genes, Hep appeared to modulate the impact of EV71 infection on the expression pattern of the genes. Conclusions: The findings of this research may provide initial assistance in new directions for studies to design molecular drug targets against EV71 infection.

Facial alveolar bone wall width – a cone‐beam computed tomography study inAsians

The width of the facial alveolar bone wall is crucial for long-term successful esthetic outcomes of implants immediately placed into extraction sockets. A threshold of 2 mm is recommended to minimize buccal vertical bone resorption. To assess the width of the facial alveolar bone wall using cone-beam computed tomography images (CBCT). Retrospective CBCT images were acquired from a representative sample of Asians using the i-CAT classic system with a 0.4-mm voxel size. At random, 200 CBCT images were selected according to predefined criteria. The DICOM file was imported into the i-CAT Vision software. In the panoramic screen, the middle of each tooth was selected, and in the sagittal window, the middle cross section was selected for performing the measurements using a computer. The vertical distance from the alveolar crest (BC) - cemento-enamel junction (CEJ) was measured. The width of the facial alveolar bone wall was measured at three locations: 1, 3, and 5 mm apical to BC. Descriptive statistics, frequency analyses, and multi-level comparisons were performed. The sample consisted of 74 men and 126 women (mean age of 37.2 years; range 17-82 years). A total of 3618 teeth were assessed. There was no significant difference between the values of right and left sides, or between genders. However, statistically significant differences were observed between age groups at all levels. The distance from CEJ to BC varied from 0.4 to 4 mm, with an overall tendency to increase with age. The mean width of the facial alveolar bone wall at anterior teeth was 0.9 mm and increased toward posterior regions. Rarely, a width of 2 mm was yielded (0.6-1.8% for anterior teeth, 0.7-30.8% for posterior teeth). At a 5-mm distance from BC, minimal widths of facial alveolar bone were identified for the anterior teeth. The frequency of dehiscence ranged from 9.9% to 51.6% for anterior and 3.1% to 53.6% for posterior teeth, respectively. A thin facial alveolar bone wall was usually present in both jaws. Hence, for most patients, adjunctive bone augmentation may be needed when installing implants in areas of esthetic concern.

Abstract: An International Comparison of Private and Public Schools Using Multilevel Propensity Score Methods and Graphics

As can be seen from the recent Special Issue of MBR on propensity score analysis (PSA) methods, the use of PSA has gained increasing popularity for estimating causal effects in observational studies. However, PSA use with multilevel or clustered data has been limited, and to date there seems to have been no development of specialized graphics for such data. This paper introduces the multilevelPSA (http://multilevelPSA.r-forge.r-project.org) package for R that provides cluster-based functions for estimating propensity scores as well as graphics to exhibit results for multilevel data. This work extends to the multilevel case the framework for visualizing propensity score analysis introduced by Helmreich and Pruzek (2009). International data from the Programme for International Student Assessment (Organization for Economic Co-operation and Development, 2009) are comprehensively examined to compare private with public schools on reading, mathematics, and science outcomes after adjusting for covariate differences in the multilevel context. Particularly for analyses of large data sets, focusing on statistical significance is limiting. As can readily be seen, overall results favor “private” over “public” schools, at least for end of secondary school math achievement. But the graphics provide a more nuanced understanding of the nature and magnitude of adjusted differences for countries. Furthermore, the graphics are readily interpreted by a nontechnical audience. Broadly speaking, it is seen that modern graphics can enhance and extend conventional numerical summaries by focusing on details of what data have to say for multilevel comparisons of many countries based on propensity score methods.