Ramsey numbers for sets of small graphs

AbstractThe Ramsey number r=r(G1-G2-⋯-Gm,H1-H2-⋯-Hn) denotes the smallest r such that every 2-coloring of the edges of the complete graph Kr contains a subgraph Gi with all edges of one color, of a subgraph Hi with all edges of a second color. These Ramsey numbers are determined for all sets of graphs with at most four vertices, and in the diagonal case (m=n,Gi=Hi) for all pairs of graphs, one with at most four and the other with five vertices, so as for all sets of graphs with five vertices

Investigating the loess–palaeosol sequence of Bahlingen-Schönenberg (Kaiserstuhl), southwestern Germany, using a multi-methodological approach

Loess–palaeosol sequences (LPSs) are key archives for the reconstruction of Quaternary environmental conditions, but there is a lack of investigated records from the southern Upper Rhine Graben (southwestern Germany). To close this gap, a LPS at Bahlingen-Schönenberg was investigated at high resolution using a multi-method approach. Infrared stimulated luminescence screening reveals a major hiatus in the lower part of the LPS that according to luminescence dating is older than marine isotope stage (MIS) 4. The section above the hiatus formed by quasi-continuous loess sedimentation between ca. 34 and 27 ka, interrupted by phases of weak reductive pedogenesis. The fact that this pedogenesis is much weaker compared to corresponding horizons in the more northerly part of the Upper Rhine Graben could be due to regionally drier conditions caused by a different atmospheric circulation pattern at the time of deposition. Our results reinforce earlier notions that the major environmental shifts leading into the Last Glacial Maximum (LGM) of southern Central Europe significantly predate the transition of MIS 3 to 2 (ca. 29 ka). In particular, the last massive phase of loess accumulation started several thousand years prior to the arrival of glaciers in the foreland of the Alps, which raises questions regarding the source and transport paths of the dust. It is also noted that no loess dating to the LGM or the time thereafter was observed due to either a lack of deposition or later erosion.Löss-Paläoboden Sequenzen (LPS) sind Schlüsselarchive für die Rekonstruktion von quartären Umweltbedingungen, aber es mangelt an der Untersuchung solcher Abfolgen aus dem südlichen Oberrheingraben. Um diese Lücke zu schließen, wurde eine LPS bei Bahlingen-Schönenberg mit einem multimethodischen Ansatz hochauflösend untersucht. Die Untersuchung mit Infrarot Stimulierter Lumineszenz Screening zeigt einen Hiatus im unteren Teil der LPS, der laut Lumineszenzdatierungen älter ist als das Marine Isotopenstadium (MIS) 4. Der Abschnitt oberhalb des Hiatus bildete sich durch quasi-kontinuierliche Lössablagerung zwischen ca. 34 und 27 ka, unterbrochen von Phasen schwacher reduktiver Pedogenese. Da die Pedogenese im Vergleich zu entsprechenden Horizonten im nördlicheren Teil des Oberrheingrabens viel schwächer ausgeprägt ist, könnte dies auf regional trockenere Bedingungen zurückzuführen sein, verursacht durch ein anderes atmosphärisches Zirkulationsmuster zur Zeit der Ablagerung. Unsere Ergebnisse bestätigen frühere Annahmen, dass die großen Umweltveränderungen, die zum letzten glazialen Maximum (LGM) im südlichen Mitteleuropa führten, deutlich vor dem Übergang von MIS 3 zu 2 (ca. 29 ka) lagen. Insbesondere begann die letzte massive Phase der Lössakkumulation mehrere tausend Jahre vor der Ankunft der Gletscher im Alpenvorland, was Fragen zu den Quellen und Transportwegen des Staubs aufwirft. Es ist auch festzustellen, dass kein Löss aus dem LGM oder der Zeit danach gefunden wurde, entweder aufgrund fehlender Ablagerung oder späterer Erosion

Dental practitioner recruitment for a randomized clinical trial in the field to evaluate the performance of a new glass ionomer restoration material

Background: In 2009, we began recruiting dental practitioners across Germany to participate in a clinical trial to evaluate the clinical performance of EQUIA, a new glass ionomer restoration material. The aim of this paper is to discuss the outcomes of the dental practitioner recruitment and outline the process of establishing a practice-based research network. Methods: Study proposals were sent to randomly selected dental offices in 29 cities in Germany. The proposals were sent until a minimum of 10 clinics in each city declared participation. Later on, briefing lectures informed the participating practitioners about the design, methods, and material application procedure. Participants were familiarized with the guidelines of Good Manufacturing Practice (GMP) and Good Epidemiological Practice (GEP). A questionnaire describing the characteristics of each dental office was filled out by the participating practitioner. Additionally, participation levels were characterized according to the socioeconomic status and geographic districts of residence in Germany (Regions 0 to 9). The associations between the characteristics were tested by the Kruskal-Wallis Test and Chi-squared test (P < 0.05). Results: A total of 3194 private dental clinics were invited, 1712 clinics refused to participate, 1195 did not respond to the invitation, and 323 agreed to participate. Only 144 clinics participated in the lectures held in their cities and signed the participation agreement. Based on their geographic location, the highest participation was in Region 2 with a participation rate of 14.3 %, and the lowest participation was in Region 6 with a participation rate of 1.7 %. Regions with the lowest rate of unemployment and relatively higher rates of income (Regions 7 and 8) had the highest rate of refusals (86 %). Conclusion: The initial results of the dental practitioner recruitment in this study suggest that the recruitment and pre-randomization design were successful, and by reaching out to a considerable number of private dental clinics to participate, we were able to recruit a smaller number of highly motivated dentists in this clinical study. Regional differences in socioeconomic status, practitioner specialization, and differences in patient health care insurance have to be considered when recruiting dental practitioners for clinical trials

Adenine-induced hyperphosphatemia in a murine model of renal insufficiency

Hyperphosphatemia in chronic kidney disease (CKD) patients is a risk factor for cardiovascular events, progressive kidney failure, and mortality. Improved therapeutic interventions to control hyperphosphatemia depend greatly on robust animal models that recapitulate the CKD disease process. Murine-based models of CKD as compared to rat models present significant advantages due to available genetic knockout lines that permit mechanistic dissection of CKD etiologies. The rat adenine model of renal failure has been extensively studied, and studies are now emerging describing adenine-induced renal failure in murine models. However, these newly developed murine models have not fully described the responses to calcitriol and phosphate binders, and the reported effects of adenine on serum phosphate is often lacking in murine models. Therefore, the objectives of this study were: 1) To induce hyperphosphatemia in mice using adenine with minimal mortality, and 2) Report the influence of calcitriol and phosphate binders on the disease process through measurement of serum phosphate and histology. In one approach, C57BL/6 male mice gavaged with 4 or 6 mg adenine/day, as compared to 0 mg adenine/day developed hyperphosphatemia, with low mortality. In a second approach, calcitriol exacerbated adenine-induced increases in serum phosphate at day 7 of adenine administration (p\u3c0.05). Notably, adenine treated mice had 4-fold increased stomach weights vs. non-adenine treated mice (p\u3c0.0001). The addition of a phosphate binder (experiment 3, sevelamer hydrochloride) was ineffective at preventing an adenine-induced increase in blood phosphate, a finding that likely resulted from adenine’s inhibition of gastric emptying. We report the successful use of adenine to induce hyperphosphatemia, that the hyperphosphatemic status is exacerbated by calcitriol, and a limitation of the model for studying oral therapies for hyperphosphatemia

Collaborative meta-analysis finds no evidence of a strong interaction between stress and 5-HTTLPR genotype contributing to the development of depression

The hypothesis that the S allele of the 5-HTTLPR serotonin transporter promoter region is associated with increased risk of depression, but only in individuals exposed to stressful situations, has generated much interest, research, and controversy since first proposed in 2003. Multiple meta-analyses combining results from heterogeneous analyses have not settled the issue. To determine the magnitude of the interaction and the conditions under which it might be observed, we performed new analyses on 31 datasets containing 38 802 European-ancestry subjects genotyped for 5-HTTLPR and assessed for depression and childhood maltreatment or other stressful life events, and meta-analyzed the results. Analyses targeted two stressors (narrow, broad) and two depression outcomes (current, lifetime). All groups that published on this topic prior to the initiation of our study and met the assessment and sample size criteria were invited to participate. Additional groups, identified by consortium members or self-identified in response to our protocol (published prior to the start of analysis1) with qualifying unpublished data were also invited to participate. A uniform data analysis script implementing the protocol was executed by each of the consortium members. Our findings do not support the interaction hypothesis. We found no subgroups or variable definitions for which an interaction between stress and 5-HTTLPR genotype was statistically significant. In contrast, our findings for the main effects of life stressors (strong risk factor) and 5-HTTLPR genotype (no impact on risk) are strikingly consistent across our contributing studies, the original study reporting the interaction, and subsequent meta-analyses. Our conclusion is that if an interaction exists in which the S allele of 5-HTTLPR increases risk of depression only in stressed individuals, then it is not broadly generalizable, but must be of modest effect size and only observable in limited situations

Cephalometric analyses for cleft patients: a statistical approach to compare the variables of Delaire’s craniofacial analysis to Bergen analysis

Objectives!#!Cephalometric analyses using lateral craniofacial radiographs are common diagnostic procedures for evaluating skeletal patterns. However, in patients with pronounced abnormalities like cleft lip and palate, standard cephalometric analyses and landmarks may not be suitable. This study aims to clarify whether the inclusion of landmarks less compromised by the cleft defect or located outside the cleft area results in a different cephalometric assessment of the viscerocranium. Delaire's whole-skull analysis and Bergen analysis were examined for similarities and underlying common observations.!##!Materials/methods!#!Based on the cephalometric evaluation of 217 patients with different types of non-syndromal cleft formation, Delaire and Bergen analysis were compared using three statistical methods: correlation analysis, factor analysis, and cluster analysis. Reproducibility was assessed by Bland-Altman plots, intraclass correlation coefficients, mean absolute differences, and coefficients of variability.!##!Results!#!Although Delaire analysis and Bergen analysis are based on different concepts and landmarks, a majority of corresponding variables was found. Certain aspects of craniofacial base relation and craniospinal articulation are only assessed by Delaire analysis. All but one variable showed very good reproducibility.!##!Conclusions!#!The inclusion of landmarks less compromised by or located outside the cleft area does not result in variables that provide a different assessment of the viscerocranial area.!##!Clinical relevance!#!The findings contradict the concept of invalidity of landmarks compromised by the cleft defect or located within the affected cleft area. Within the scope of its viscerocranial field of view, Bergen analysis appears to be on a par with Delaire analysis in the diagnosis of cleft patients

Stabilizing Removable Partial Dentures by Immediate or Delayed Loading of Mini-implants: Chewing Efficiency in a Randomized Controlled Clinical Trial.

PURPOSE The aim of this investigation was to compare the chewing efficiency after immediate and delayed loading of mini-implants that served as supplementary support for removable partial dentures (RPDs). MATERIALS AND METHODS In this four-center randomized trial, patients who had RPDs in arches with unfavorable tooth distributions, ie, no canine and at most two posterior teeth in one or both quadrants, received strategic mini-implants with ball abutments. The mini-implants in group A were loaded immediately either by housings with O-rings (insertion torque ≥ 35 Ncm) or by soft relining material (insertion torque < 35 Ncm). In group B, the RPDs were only hollowed over the balls. After 4 months, the soft relined RPDs and all RPDs of group B received the housings. Masticatory efficiency was evaluated with a validated mixing ability test of two-colored chewing gum before surgery and 14 days, 4 months (before housing pickup), 4.5 months, and 12 months after surgery. The circular variance of hue was the measure of mixing. RESULTS From 76 participants with 79 RPDs, 38 each were randomly allocated to group A or B. In group A, the housings in six participants were picked up immediately, and the remaining RPDs were primarily soft relined. There was a significant group difference only after 4 months. The mixing ability was better after immediate loading than after delayed loading (P < .0001). In group B, the chewing efficiency was notably deteriorated after the RPDs were hollowed over the ball abutments. However, immediately after all housings were picked up, the chewing efficiency in both groups was substantially improved, and the variance of hue values after 1 year were very similar in the groups. CONCLUSION The chewing performance can be improved by inserting supplementary mini-implants under existing RPDs with unfavorable tooth support. This improvement occurred faster by immediate loading than by delayed loading

New insights in the reproducibility of visual and electronic tooth color assessment for dental practice

Background The aim of the study was to compare a 2D and 3D color system concerning a variety of statistical and graphical methods to assess validity and reliability of color measurements, and provide guidance on when to use which system and how to interpret color distance measures, including Delta E and d(0M1). Methods The color of teeth 14 to 24 of 35 patients undergoing regular bleaching treatment was visually assessed and electronically measured with the spectrophotometer Shade Inspector (TM). Tooth color was recorded before bleaching treatment, after 14 days, and again after 6 months. VITAPAN (R) Classical (2D) and VITA-3D-Master (R) (3D) served as reference systems. Results Concerning repeated measurements, the 2D system was superior to the 3D system, both visually and electronically in terms of Delta E and d(OM1), for statistics of agreement and reliability. All four methods showed strong patterns in Bland-Altman plots. In the 3D system, hue was less reliable than lightness and chroma, which was more pronounced visually than electronically. The smallest detectable color difference varied among the four methods used, and was most favorable in the electronic 2D system. Comparing the methods, the agreement between the 2D and 3D system in terms of Delta E was not good. The reliability of the visual and electronic method was essentially the same in the 2D and 3D systems; this comparability is fair to good