668 research outputs found
Test of the purchasing power parity hypothesis by using panel structural break test for transition economies
This paper is aim to test the validity of the purchasing power parity hypothesis by analyzing the transition economies such as Bulgaria, Czech Republic, Hungary, Poland, Romania. For this purpose, the minimum LM unit root test with one structural break is applied to real exchange rate data.PPP, MADF, LM test.
The Reliability and Reproducibility of Conventional, Digital and CT Created Cephalograms: A Comparative Study
poster abstractObjective: The purpose of this retrospective radiographic study was to determine the reliability and reproducibility of skeletal and dental measurements of lateral cephalograms created from computed tomography (CT) scan compared to the conventional and digital lateral cephalograms.
Method: Following reliability studies, CT records of 30 patients were obtained from the archives. The lateral cephalometric radiographs of these patients were initially manually traced. Then the same radiographs were scanned and traced using Dolphin Imaging software Version 11 (Dolphin Imaging, Chatsworth, CA, USA). Totally 16 (10 angular and 6 linear) measurements were performed. Cephalometric measurements performed on conventional, digital and CT created cephalograms were compared statistically using repeated measures analysis of variance. Statistical significance was set at p<0.05 level.
Result: The intrarater reliability test for each method showed high values r >.090 except for the mandibular length which had a correlation of 0.82 for the CT created cephalogram. Five measurements (N-A- Pog, N-S, ANS-PNS, Co-ANS and Co-Gn) were found to be significantly different between the CT created and conventional cephalograms and three measurements (SNB, ANB, and /1-MP) were found to be significantly different between the CT created and digital cephalograms.
Conclusion: The measurement differences between the conventional, digital and CT created cephalograms are statistically significant, but clinically acceptable
Orthodontic Soft Tissue Parameters: A Comparison of CBCT and 3dMD
poster abstractObjectives: Orthodontists rely heavily on soft tissue analysis to determine esthetics and treatment stability. Although the reliability of three dimensional photography (3dMD) and cone beam computed tomography (CBCT) is established, little data exists comparing the soft tissue measurements between these two imaging modalities. The aim of this retrospective study is to compare the equivalence of soft tissue measurements between the 3dMD imaging system and the segmented skin surface derived from i-CAT CBCT. Methods: Seventy preexisting 3dMD extraoral photographs and CBCT scans taken within minutes of each other for the same subjects were superimposed using 3dMD Vultus software on soft tissue. Images were registered according to hard tissue planes in three dimensions. Following reliability studies, 28 soft tissue measurements were selected and recorded on both imaging modalities. The measures were then compared between the two images to analyze their equivalence. Intraclass correlation coefficients (all ICCs >.8) and Bland-Altman plots were used to assess the inter- / intra-examiner repeatability and agreement. Summary statistics were calculated for all measurements. To demonstrate equivalence of the two methods, the difference needed a 95% confidence interval contained entirely within the equivalence limits defined by repeatability results (twice the within-subject standard deviation of CBCT). Results: Statistically significant differences were reported for the following measurements: vermilion height (Ls-Li), mouth width (CH[R]–CH[L]), total facial width (Tr[R] – Tr[L]), mouth symmetry (Ch[R] to Sup. Facial Plane), ST Lip Thickness (LI to mand CI), and eye symmetry (Exoc R & L to Sup. Facial Plane). Conclusions: There are areas of non-equivalence between the two imaging methods. Differences are clinically acceptable from the orthodontic point of view
Nasal Airway and Septal Variation in Unilateral and Bilateral Cleft Lip and Palate
Cleft lip and palate (CLP) affects the dentoalveolar and nasolabial facial regions. Internal and external nasal dysmorphology may persist in individuals born with CLP despite surgical interventions. 7–18 year old individuals born with unilateral and bilateral CLP (n = 50) were retrospectively assessed using cone beam computed tomography. Anterior, middle, and posterior nasal airway volumes were measured on each facial side. Septal deviation was measured at the anterior and posterior nasal spine, and the midpoint between these two locations. Data were evaluated using principal components analysis (PCA), multivariate analysis of variance (MANOVA), and post-hoc ANOVA tests. PCA results show partial separation in high dimensional space along PC1 (48.5% variance) based on age groups and partial separation along PC2 (29.8% variance) based on CLP type and septal deviation patterns. MANOVA results indicate that age (P = 0.007) and CLP type (P ≤ 0.001) significantly affect nasal airway volume and septal deviation. ANOVA results indicate that anterior nasal volume is significantly affected by age (P ≤ 0.001), whereas septal deviation patterns are significantly affected by CLP type (P ≤ 0.001). Age and CLP type affect nasal airway volume and septal deviation patterns. Nasal airway volumes tend to be reduced on the clefted sides of the face relative to non-clefted sides of the face. Nasal airway volumes tend to strongly increase with age, whereas septal deviation values tend to increase only slightly with age. These results suggest that functional nasal breathing may be impaired in individuals born with the unilateral and bilateral CLP deformity
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The Eukaryotic Proteome Is Shaped by E3Â Ubiquitin Ligases Targeting C-Terminal Degrons
Degrons are minimal elements that mediate the interaction of proteins with degradation machineries to promote proteolysis. Despite their central role in proteostasis, the number of known degrons remains small and a facile technology to characterize them is lacking. Using a strategy combining Global Protein Stability (GPS) profiling with a synthetic human peptidome, we identify thousands of peptides containing degron activity. Using CRISPR screening, we established that the stability of many proteins is regulated through degrons located at their C-terminus. We characterize eight Cullin-RING E3 ubiquitin ligase (CRL) complexes adaptors that regulate C-terminal degrons including six CRL2 and two CRL4 complexes and computationally implicate multiple non-CRLs in end recognition. Human proteome analysis revealed that the C-termini of eukaryotic proteins are depleted for C-terminal degrons, suggesting an E3 ligase-dependent modulation of proteome composition. Thus, we propose that a series of ‘C-end rules’ operate to govern protein stability and shape the eukaryotic proteome
Three and four current reversals versus temperature in correlation ratchets with a simple sawtooh potential
Transport of Brownian particles on a simple sawtooth potential subjected to
both unbiased thermal and nonequilibrium symmetric three-level Markovian noise
is considered. The new effects of three and four current reversals as a
function of temperature are established in such correlation ratchets. The
parameter space coordinates of the fixed points associated with these current
reversals and the necessary and sufficient conditions for the existence of the
novel current reversals are found.Comment: 4 pages, 5 figures; some changes introduced; accepted for publication
in Physical Review
Irreversible and reversible modes of operation of deterministic ratchets
We discuss a problem of optimization of the energetic efficiency of a simple
rocked ratchet. We concentrate on a low-temperature case in which the
particle's motion in a ratchet potential is deterministic. We show that the
energetic efficiency of a ratchet working adiabatically is bounded from above
by a value depending on the form of ratchet potential. The ratchets with
strongly asymmetric potentials can achieve ideal efficiency of unity without
approaching reversibility. On the other hand we show that for any form of the
ratchet potential a set of time-protocols of the outer force exist under which
the operation is reversible and the ideal value of efficiency is also achieved.
The mode of operation of the ratchet is still quasistatic but not adiabatic.
The high values of efficiency can be preserved even under elevated
temperatures
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