Slight Differences In Magnitude Research Articles

Quantum Tunneling and Complex Dynamics in the Suris's Integrable Map.

Quantum tunneling in a two-dimensional integrable map is studied. The orbits of the map are all confined to the curves specified by the one-dimensional Hamiltonian. It is found that the behavior of tunneling splitting for the integrable map and the associated Hamiltonian system is qualitatively the same, with only a slight difference in magnitude. However, the tunneling tails of the wave functions, obtained by superposing the eigenfunctions that form the doublet, exhibit significant differences. To explore the origin of the difference, we observe the classical dynamics in the complex plane and find that the existence of branch points appearing in the potential function of the integrable map could play the role of yielding non-trivial behavior in the tunneling tail. The result highlights the subtlety of quantum tunneling, which cannot be captured in nature only by the dynamics in the real plane.

Climatology and interannual variability of type-dependent aerosol optical depth and vertical distribution over southwest China and northern India from multiple satellite and aerosol reanalysis datasets

Aerosol loading and properties have an important influence on the radiative effect of aerosols and regional climate change. Based on the long-term datasets of aerosol optical products retrieved from multiple satellite observations (MODIS/Terra, MODIS/Aqua, MISR, and CALIOP/CALIPSO) and a reanalysis product (CAMS) from 2007 to 2019, the climatology and interannual variability in total aerosol optical depth (AOD) and type-dependent AODs related to aerosol particle properties and components over southwest China (SWC) and northern India (NI) are investigated, and the vertical distribution of type-dependent aerosol extinctions are also examined. Overall, consistent spatial distribution characteristics of the AOD climatology are captured across the different datasets, albeit with slight differences in magnitude. Multi-year mean high AODs are mainly concentrated in areas such as the Sichuan Basin (SCB) (∼0.5) and NI (∼0.6), dominated by anthropogenic aerosols, and the Tarim Basin (∼0.5), dominated by mineral dust aerosols. In contrast, the central Tibetan Plateau (CTP) area, with a relatively clean background, has a lower AOD (∼0.1) on a multi-year average basis. When the total AOD is separated by chemical components, the CAMS reanalysis demonstrates that sulfate and carbonaceous aerosols (CAs) contribute nearly equally to AOD in SCB, while CAs is the largest contributor to the high aerosol loading in NI. An enhanced vertical aerosol extinction coefficient (AEC) is mainly located below 1 km in both SCB and NI, reaching 0.35 km−1 and 0.55 km−1. In CTP, the AEC has two peaks (∼0.02 km−1) at 2.5 km and 3.5 km. By partitioning the column AOD by different altitude ranges, we find that about 73.8% (80.6%) of the AOD in SCB (NI) is located in the lower troposphere (0–2 km). The resulting trend analyses show that a significant decreasing (increasing) trend (P < 0.05) in AOD in SCB (NI) is accurately captured by both the satellite products and the CAMS reanalysis. In contrast, a significant decline (P < 0.1) in the CTP region is observed in CAMS only, while a non-significant decline is detected in the satellite products. The results of this study have potential implications for understanding the vertical distribution and interannual variability of regional aerosol loading.

Strong Genetic Effects on Bone Mineral Density in Multiple Locations with Two Different Techniques: Results from a Cross-Sectional Twin Study.

Background and Objectives: Previous studies have demonstrated that risk of hip fracture is at least partly heritable. The aim of this study was to determine the magnitude of the genetic component of bone mineral density (BMD), using both X-ray and ultrasound assessment at multiple sites. Materials and Methods: 216 adult, healthy Hungarian twins (124 monozygotic, MZ, 92 dizygotic, DZ; mean age 54.2 ± 14.3 years), recruited from the Hungarian Twin Registry with no history of oncologic disease underwent cross-sectional BMD studies. We measured BMD, T- and Z-scores with dual energy X-ray absorptiometry (DEXA) at multiple sites (lumbar spine, femoral neck, total hip and radius). Quantitative bone ultrasound (QUS) was also performed, resulting in a calculated value of estimated bone mineral density (eBMD) in the heel bone. Heritability was calculated using the univariate ACE model. Results: Bone density had a strong genetic component at all sites with estimates of heritability ranging from 0.613 to 0.838 in the total sample. Lumbar BMD and calcaneus eBMD had major genetic components with estimates of 0.828 and 0.838 respectively, and least heritable (0.653) at the total hip. BMD of the radius had also a strong genetic component with an estimate of 0.806. No common environmental effect was found. The remaining variance was influenced by unique environment (0.162 to 0.387). In females only, slightly higher additive genetic estimates were found, especially in the case of the femoral neck and total hip. Conclusion: Bone mineral density is strongly heritable, especially in females at all locations using both DEXA and QUS, which may explain the importance of family history as a risk factor for bone fractures. Unshared environmental effects account for the rest of the variance with slight differences in magnitude across various bone regions, supporting the role of lifestyle in preventing osteoporotic fractures with various efficacy in different bone regions.

Health and economic impacts associated with smoke from summer bushfires in Australia, 2000-2020

Background: Summer bushfires are an integral feature of temperate forests in Australia, which are largely dominated by eucalypts. Global warming is changing the pattern of bushfire activity by increasing the frequency of weather conditions associated with extreme fires. Objective: To quantify health impacts and associated economic costs attributable to bushfire smoke-related PM2.5 produced during Australian fire seasons (1st October - 31st March) since 2000/2001. Methods: We included all regions in temperate climate zones in Australia with long term air monitoring networks, covering approximately 90% of the population. We applied standard methods for health impact assessments to estimate the number of premature deaths, cardiorespiratory hospitalizations and asthma emergency department (ED) attendances attributable to bushfire smoke-related particulate matter (PM2.5). Health costs were quantified using the value of a statistical life for mortality and average health care costs for morbidity outcomes. We did a sensitivity analysis on the PM2.5 cut-off points used to identify fire smoke affected days, and applied alternative economic valuation methods to estimate health costs. Results: We found large interannual variation. The 2019/2020 fire season was the worst in recent history with estimated health costs of $1.96 billion (AUD), more than 9 times the median estimated costs of the past 19 fire seasons ($204 million). The two next worst seasons were 2002/2003 and 2006/2007 with estimated costs of $552 million and $360 million respectively. For 2019/2020 we estimated smoke-related health impacts of 431 premature deaths, 3240 cardiorespiratory hospitalizations, and 1333 asthma ED attendances. Our sensitivity analysis shows slight differences in magnitude of impacts for each fire season, but the relative importance of these remains unaltered. Conclusions: Bushfire smoke is associated with substantial health economic costs. Our analysis illustrates the potential for major increases in the health burden from air pollution due to increased bushfire risk associated with the changing climate.

Long-term stability, reproducibility, and statistical sensitivity of a telemetry-instrumented dog model: A 27-month longitudinal assessment

IntroductionICH guidelines, as well as best-practice and ethical considerations, provide strong rationale for use of telemetry-instrumented dog colonies for cardiovascular safety assessment. However, few studies have investigated the long-term stability of cardiovascular function at baseline, reproducibility in response to pharmacologic challenge, and maintenance of statistical sensitivity to define the usable life of the colony. These questions were addressed in 3 identical studies spanning 27months and were performed in the same colony of dogs. MethodsTelemetry-instrumented dogs (n=4) received a single dose of dl-sotalol (10mg/kg, p.o.), a β1 adrenergic and IKr blocker, or vehicle, in 3 separate studies spanning 27months. Systemic hemodynamics, cardiovascular function, and ECG parameters were monitored for 18h post-dose; plasma drug concentrations (Cp) were measured at 1, 3, 5, and 24h post-dose. ResultsBaseline hemodynamic/ECG values were consistent across the 27-month study with the exception of modest age-dependent decreases in heart rate and the corresponding QT-interval. dl-Sotalol elicited highly reproducible effects in each study. Reductions in heart rate after dl-sotalol treatment ranged between −22 and −32 beats/min, and slight differences in magnitude could be ascribed to variability in dl-sotalol Cp (range=3230–5087ng/mL); dl-sotalol also reduced LV-dP/dtmax 13–22%. dl-Sotalol increased the slope of the PR–RR relationship suggesting inhibition of AV-conduction. Increases in the heart-rate corrected QT-interval were not significantly different across the 3 studies and results of a power analysis demonstrated that the detection limit for QTc values was not diminished throughout the 27month period and across a range of power assumptions despite modest, age-dependent changes in heart rate. DiscussionThese results demonstrate the long-term stability of a telemetry dog colony as evidenced by a stability of baseline values, consistently reproducible response to pharmacologic challenge and no diminished statistical sensitivity over time.

Effect of restoration type on the stress distribution of endodontically treated maxillary premolars; Three-dimensional finite element study

The purpose of this study was to investigate the effects of four restorative materials under various occlusal loading conditions on the stress distribution at the CEJ of buccal. palatal surface and central groove of occlusal surface of endodontically treated maxillary second premolar, using a 3D finte element analysis. A 3D finite element model of human maxillary second premolar was endodontically treated. After endodontic treatment, access cavity was filled with Amalgam, resin, ceramic or gold of different mechanical properties. A static 500N forces were applied at the buccal (Load-1) and palatal cusp (Load-2) and a static 170N forces were applied at the mesial marginal ridge and palatal cusp simultaneously as centric occlusion (Load-3). Under 3-type Loading condition, the value of tensile stress was analyzed after 4-type restoration at the CEJ of buccal and palatal surface and central groove of occlusal surface Excessive high tensile stresses were observed along the palatal CEJ in Load-1 case and buccal CEJ in Load-2 in all of the restorations. There was no difference in magnitude of stress in relation to the type of restorations. Heavy tensile stress concentrations were observed around the loading point and along the central groove of occlusal surface in all of the restorations. There was slight difference in magnitude of stress between different types of restorations. High tensile stress concentrations around the loading points were observed and there was no difference in magnitude of stress between different types of restorations in Load-3.

Physical consequences of a general excess of charge

The possibility of a general excess of charge in the universe is proposed. If such exists, even to the extent of only 2 parts in 10 18 , sufficiently powerful electric forces result to produce the observed expansion of the universe on the basis of Newtonian mechanics. If the excess occurs as a slight difference in magnitude of the proton and electron charges, the hypothesis may be on the verge of what could be established by experiment. If creation of matter, and also necessarily charge, is assumed, the Maxwell equations must be modified to avoid strict conservation. The appropriate modification is shown to involve additional terms in the current and charge-density equations proportional to the vector and scalar potentials. When applied to a spherically symmetrical smoothed-out universe, the revised equations establish almost rigorously that electrical requirements imply a strict velocitydistance law for the mass motion of expansion. For agreement with observation, the requisite charge on the proton would be (1 + y ) e where y = 2 x 10 -18 , or, if the charges are strictly equal in magnitude, it requires 1 + y protons for every electron, with the same value of y . The value of the Hubble constant and of the smoothed-out density of matter in the universe are shown to be simply related by the theory to the rate of creation. The same solution is shown to hold equally in de Sitter space-time, and the principle of complete equivalence of all observers at all times is thereby demonstrated to be a property of the solution. Construction of the corresponding stress-energy tensor enables the factor associated with the new terms in the Maxwell equations to be directly related to the observable radius of the universe. On the first form of the charge-excess hypothesis, galaxies and clusters of galaxies (with their haloes) arise as ionized condensation units within the general background distribution. Since the units are conducting, they remain electrically neutral, and therefore grow and are controlled by ordinary gravitational forces. Moreover, because they are conducting, the units will expel their excess charge in the form of free protons. It is shown that the electrostatic potential at the surface of a unit is maintained by creation at such a value that the protons are expelled with energies corresponding to the highest energy cosmic rays. These units will take part in the general expansion, not under the direct action of the electric repulsion, but because they form and grow from the expanding background material. Any small departure in velocity of a unit from the local value would be quickly removed through the gravitational braking action associated with accretion of further material. The gravitational potential at the surface of a unit is such that infalling hydrogen atoms will have energy of motion corresponding to temperature of the order of a million degrees, and the outer parts of the units at least will be at high temperature.

Notes on a possible photometric effect from Struve's theory of whirlpools around binary systems.

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Notes on a possible photometric effect from Struve's theory of whirlpools around binary systems. Yu, Ch'ing-Sung Abstract Struve's recent theory of revolving streams around binary stars, which has been amply supported by spectroscopic evidences, appears to receive an additional proof from a photometric effect observed in the light curve of an eclipsing binary. In his photometric study of CG Cygni, the writer noted in 19~22 that the total light of the binary at phase 0.25 lS greater than that at phase O~.75 by 0 045 mag. This was at first puzzling, since at these two positions, the components are symmetrically identical and therefore the brightness of the system should remain the same. However, it seems an explanation can be obtained now if we assume, following Struve, that the system is surrounded by a whirlpool ring of gas. The portion facing the observer at o~25 is hotter, according to the theory, than that at O~75, giving rise to the slight difference in magnitude. It is pointed out that for CG Cygni a difference of Ioo0K is sufficient to account for the discrepancy. Reasons are given to explain the lack of similar observations so far, but suggestions are made to look for this effect in the future with highly sensitive photoelectric equipment. High A ltitude Observatory, Climax, Colo. Publication: The Astronomical Journal Pub Date: April 1949 DOI: 10.1086/106232 Bibcode: 1949AJ.....54..141Y full text sources ADS |