On the Klein-Gordon equation and hyperbolic pseudoanalytic function theory

Elliptic pseudoanalytic function theory was considered independently by Bers and Vekua decades ago. In this paper we develop a hyperbolic analogue of pseudoanalytic function theory using the algebra of hyperbolic numbers. We consider the Klein-Gordon equation with a potential. With the aid of one particular solution we factorize the Klein-Gordon operator in terms of two Vekua-type operators. We show that real parts of the solutions of one of these Vekua-type operators are solutions of the considered Klein-Gordon equation. Using hyperbolic pseudoanalytic function theory, we then obtain explicit construction of infinite systems of solutions of the Klein-Gordon equation with potential. Finally, we give some examples of application of the proposed procedure

The Marmara Sea Gateway since ~16 ky BP: non-catastrophic causes of paleoceanographic events in the Black Sea at 8.4 and 7.15 ky BP

The Late Quaternary history of connection of the Black Sea to the Eastern Mediterranean has been intensely debated. Ryan, Pitman and coworkers advocate two pulses of outflow from the Black Sea to the world ocean at ~16–14.7 ky BP and ~11–10 ky BP. From ~14.7–11 ky BP and from ~10–8.4 ky BP, they suggest that the level of the Black Sea fell to ~ -100 m. At 8.4 ky BP, they further claim that a catastrophic flood occurred in a geological instant, refilling the Black Sea with saline waters from the Mediterranean. In contrast, we continue to gather evidence from seismic profiles and dated cores in the Marmara Sea which demonstrate conclusively that the proposed flood did not occur. Instead, the Black Sea has been at or above the Bosphorus sill depth and flowing into the world ocean unabated since ~10.5 ky BP. This conclusion is based on continuous Holocene water-column stratification (leading to sapropel deposition in the Marmara Sea and the Aegean Sea), proxy indicators of sea-surface salinity, and migration of endemic species across the Bosphorus in both directions whenever appropriate hydrographic conditions existed in the strait. The two pulses of outflow documented by Ryan, Pitman and coworkers find support in our data, and we have modified our earlier interpretations so that these pulses now coincide with the development of mid-shelf deltas: \Delta 2 (16–14.7 ky BP) and \Delta 1 (10.5–9 ky BP) at the southern end of the Bosphorus Strait. However, continued Black Sea outflow after 9 ky BP prevented the northward advection of Mediterranean water and the entry of open-marine species into the Black Sea for more than 1000 years. Sufficient Mediterranean water to change the Sr-isotopic composition of slope and shelf water masses was not available until ~8.4 ky BP (along with the first arrival of many varieties of marine fauna and flora), whereas euryhaline molluscs did not successfully populate the Black Sea shelves until ~7.15 ky BP. Instead of relying on catastrophic events, we recognize a slow, progressive reconnection of the Black Sea to the world ocean, accompanied by significant time lags

Comparison of prescribing practices for older adults treated by female versus male physicians: A retrospective cohort study

IMPORTANCE: Subtle but important differences have been described in the way that male and female physicians care for their patients, with some evidence suggesting women are more likely to adhere to best practice recommendations. OBJECTIVE: To determine if male and female physicians differ in their prescribing practices as measured by the initiation of lower-than-recommended dose cholinesterase inhibitor (ChEI) drug therapy for dementia management. DESIGN, SETTING, AND PARTICIPANTS: All community-dwelling Ontario residents aged 66 years and older with dementia and newly dispensed an oral ChEI drug (donepezil, galantamine, or rivastigmine) between April 1, 2010 and June 30, 2016 were included. MAIN OUTCOME AND MEASURES: The association between physician sex and the initiation of a lower than recommended-dose ChEI was examined using generalized linear mixed regression models, adjusting for patient and physician characteristics. Data were stratified by specialty. Secondary analyses explored the association between physician sex and cardiac screening as well as shorter duration of the initial prescription. RESULTS: The analysis included 3,443 female and 5,811 male physicians and the majority (83%) were family physicians, Female physicians were more likely to initiate ChEI therapy at a lower-than-recommended dose (Adjusted odds ratio = 1.43,95% confidence interval = 1.17 to 1.74). Compared to their male counterparts, female physicians were also more likely to follow other conservative prescribing practices including cardiac screening (55.1% vs. 49.2%, P-value \u3c 0.001) around the time of ChEI initiation, and dispensing a shorter duration of initial prescription (41.8% vs 35.5% P-value \u3c 0.001). CONCLUSIONS: There is a statistically significant and important difference in ChEI prescribing patterns between female and male physicians, suggesting that female physicians may be more careful and conservative in their approaches. This will inform future research to determine if patients receiving lower-than-recommended initial doses also have better outcomes

Compilation of a Database of Research Information on Legume Based Grazing Systems; a Part of the Leggraze Research Project

The establishment of a publicly accessible web-resident database of published and current European research on agronomy, animal production and environmental impact of legume based grazing systems is reported. This database facilitates the sharing of information among the partners of the Low input animal production based on forage legumes for grazing systems (Leggraze), a research project funded by the UE (QL K5 CT-2001-02328). It also forms an important tool for transferring the results of the project to the wider research community and to end users in the agricultural sector and to policy makers at national and community level

Doppler temperatures from O(¹D) airglow in the daytime thermosphere as observed by the Wind Imaging Interferometer (WINDII) on the UARS satellite

International audienceFrom 1992 to 1997, the WINDII interferometer on board the UARS satellite acquired a large set of thermospheric data from the O(1D) and O(1S) airglows. We report here for the first time on daytime O(1D) Doppler temperatures obtained with version 5.11 of the WINDII data processing software. Using a statistical analysis of the temperatures independently measured by the two WINDII fields of view, we estimate that the temperature variations larger than 40 K can be considered as geophysical. Comparisons of WINDII temperatures measured during magnetically quiet days with temperatures obtained by the MSIS-90 and DTM-94 thermospheric models show a 100 K bias. We demonstrate, however, that the modeled temperature variations represent very well the mean temperature variation observed by WINDII over 4 years. We also show that the observed latitudinal/local time variation is in very good agreement with the two empirical models. Finally, the temperature variations during a magnetically disturbed day are found to be qualitatively well represented in form by the models, but largely underestimated. The presence of non-thermal atoms and instrument related issues are discussed as possible explanations for the 100 K bias between the WINDII Doppler temperatures and the empirical models

Lower thermospheric nitric oxide concentrations derived from WINDII observations of the green nightglow continuum at 553.1 nm

International audienceVertical profiles of nitric oxide in the altitude range 90 to 105 km are derived from 553 nm nightglow continuum measurements made with the Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite (UARS). The profiles are derived under the assumption that the continuum emission is due entirely to the NO+O air afterglow reaction. Vertical profiles of the atomic oxygen density, which are required to determine the nitric oxide concentrations, are derived from coordinated WINDII measurements of the atomic oxygen OI 557.7 nm nightglow emission. Data coverage for local solar times ranging from 20 h to 04 h, and latitudes ranging from 42°S to 42°N, is achieved by zonally averaging and binning data obtained on 18 nights during a two-month period extending from mid-November 1992 until mid-January 1993. The derived nitric oxide concentrations are significantly smaller than those obtained from rocket measurements of the airglow continuum but they do compare well with model expectations and nitric oxide densities measured using the resonance fluorescence technique on the Solar Mesosphere Explorer satellite. The near-global coverage of the WINDII observations and the similarities to the nitric oxide global morphology established from other satellite measurements strongly suggests that the NO+O reaction is the major source of the continuum near 553 nm and that there is no compelling reason to invoke additional sources of continuum emission in this immediate spectral region