685 research outputs found
Singular solutions of fully nonlinear elliptic equations and applications
We study the properties of solutions of fully nonlinear, positively
homogeneous elliptic equations near boundary points of Lipschitz domains at
which the solution may be singular. We show that these equations have two
positive solutions in each cone of , and the solutions are unique
in an appropriate sense. We introduce a new method for analyzing the behavior
of solutions near certain Lipschitz boundary points, which permits us to
classify isolated boundary singularities of solutions which are bounded from
either above or below. We also obtain a sharp Phragm\'en-Lindel\"of result as
well as a principle of positive singularities in certain Lipschitz domains.Comment: 41 pages, 2 figure
The Hyperfine Spin Splittings In Heavy Quarkonia
The hyperfine spin splittings in heavy quarkonia are studied using the
recently developed renormalization group improved spin-spin potential which is
independent of the scale parameter . The calculated energy difference
between the and the fits the experimental data well, while
the predicted energy difference between the center of the gravity
of states and the state of charmonium has the correct
sign but is somewhat larger than the experimental data. This is not surprising
since there are several other contributions to , which we discuss,
that are of comparable size ( MeV) that should be included, before
precise agreement with the data can be expected. The mass differences of the
, , , and
are also predicted.Comment: 17 page
Lichenometric dating (lichenometry) and the biology of the lichen genus rhizocarpon:challenges and future directions
Lichenometric dating (lichenometry) involves the use of lichen measurements to estimate the age of exposure of various substrata. Because of low radial growth rates and considerable longevity, species of the crustose lichen genus Rhizocarpon have been the most useful in lichenometry. The primary assumption of lichenometry is that colonization, growth and mortality of Rhizocarpon are similar on surfaces of known and unknown age so that the largest thalli present on the respective faces are of comparable age. This review describes the current state of knowledge regarding the biology of Rhizocarpon and considers two main questions: (1) to what extent does existing knowledge support this assumption; and (2) what further biological observations would be useful both to test its validity and to improve the accuracy of lichenometric dates? A review of the Rhizocarpon literature identified gaps in knowledge regarding early development, the growth rate/size curve, mortality, regeneration, competitive effects, colonization, and succession on rock surfaces. The data suggest that these processes may not be comparable on different rock surfaces, especially in regions where growth rates and thallus turnover are high. In addition, several variables could differ between rock surfaces and influence maximum thallus size, including rate and timing of colonization, radial growth rates, environmental differences, thallus fusion, allelopathy, thallus mortality, colonization and competition. Comparative measurements of these variables on surfaces of known and unknown age may help to determine whether the basic assumptions of lichenometry are valid. Ultimately, it may be possible to take these differences into account when interpreting estimated dates
Birthing practices of traditional birth attendants in South Asia in the context of training programmes
Traditional Birth Attendants (TBA) training has been an important component of public health policy interventions to improve maternal and child health in developing countries since the 1970s. More recently, since the 1990s, the TBA training strategy has been increasingly seen as irrelevant, ineffective or, on the whole, a failure due to evidence that the maternal mortality rate (MMR) in developing countries had not reduced. Although, worldwide data show that, by choice or out of necessity, 47 percent of births in the developing world are assisted by TBAs and/or family members, funding for TBA training has been reduced and moved to providing skilled birth attendants for all births. Any shift in policy needs to be supported by appropriate evidence on TBA roles in providing maternal and infant health care service and effectiveness of the training programmes. This article reviews literature on the characteristics and role of TBAs in South Asia with an emphasis on India. The aim was to assess the contribution of TBAs in providing maternal and infant health care service at different stages of pregnancy and after-delivery and birthing practices adopted in home births. The review of role revealed that apart from TBAs, there are various other people in the community also involved in making decisions about the welfare and health of the birthing mother and new born baby. However, TBAs have changing, localised but nonetheless significant roles in delivery, postnatal and infant care in India. Certain traditional birthing practices such as bathing babies immediately after birth, not weighing babies after birth and not feeding with colostrum are adopted in home births as well as health institutions in India. There is therefore a thin precarious balance between the application of biomedical and traditional knowledge. Customary rituals and perceptions essentially affect practices in home and institutional births and hence training of TBAs need to be implemented in conjunction with community awareness programmes
Long-Range Forces of QCD
We consider the scattering of two color dipoles (e.g., heavy quarkonium
states) at low energy - a QCD analog of Van der Waals interaction. Even though
the couplings of the dipoles to the gluon field can be described in
perturbation theory, which leads to the potential proportional to
(N_c^2-1)/R^{7}, at large distances R the interaction becomes totally
non-perturbative. Low-energy QCD theorems are used to evaluate the leading
long-distance contribution \sim (N_f^2-1)/(11N_c - 2N_f)^2 R^{-5/2} exp(-2 \mu
R) (\mu is the Goldstone boson mass), which is shown to arise from the
correlated two-boson exchange. The sum rule which relates the overall strength
of the interaction to the energy density of QCD vacuum is derived.
Surprisingly, we find that when the size of the dipoles shrinks to zero (the
heavy quark limit in the case of quarkonia), the non-perturbative part of the
interaction vanishes more slowly than the perturbative part as a consequence of
scale anomaly. As an application, we evaluate elastic \pi J/\psi and \pi J/\psi
\to \pi \psi' cross sections.Comment: 16pages, 9 eps figures; discussion extended, 2 new references added,
to appear in Phys.Rev.
ERS statement on standardisation of cardiopulmonary exercise testing in chronic lung diseases
The objective of this document was to standardise published cardiopulmonary exercise testing (CPET) protocols for improved interpretation in clinical settings and multicentre research projects. This document: 1) summarises the protocols and procedures used in published studies focusing on incremental CPET in chronic lung conditions; 2) presents standard incremental protocols for CPET on a stationary cycle ergometer and a treadmill; and 3) provides patientsâ perspectives on CPET obtained through an online survey supported by the European Lung Foundation. We systematically reviewed published studies obtained from EMBASE, Medline, Scopus, Web of Science and the Cochrane Library from inception to January 2017. Of 7914 identified studies, 595 studies with 26 523 subjects were included. The literature supports a test protocol with a resting phase lasting at least 3 min, a 3-min unloaded phase, and an 8- to 12-min incremental phase with work rate increased linearly at least every minute, followed by a recovery phase of at least 2â3 min. Patients responding to the survey (n=295) perceived CPET as highly beneficial for their diagnostic assessment and informed the Task Force consensus. Future research should focus on the individualised estimation of optimal work rate increments across different lung diseases, and the collection of robust normative data.The document facilitates standardisation of conducting, reporting and interpreting cardiopulmonary exercise tests in chronic lung diseases for comparison of reference data, multi-centre studies and assessment of interventional efficacy. http://bit.ly/31SXeB
Increased survival with enzalutamide in prostate cancer after chemotherapy
Contains fulltext :
108324.pdf (publisher's version ) (Open Access)BACKGROUND: Enzalutamide (formerly called MDV3100) targets multiple steps in the androgen-receptor-signaling pathway, the major driver of prostate-cancer growth. We aimed to evaluate whether enzalutamide prolongs survival in men with castration-resistant prostate cancer after chemotherapy. METHODS: In our phase 3, double-blind, placebo-controlled trial, we stratified 1199 men with castration-resistant prostate cancer after chemotherapy according to the Eastern Cooperative Oncology Group performance-status score and pain intensity. We randomly assigned them, in a 2:1 ratio, to receive oral enzalutamide at a dose of 160 mg per day (800 patients) or placebo (399 patients). The primary end point was overall survival. RESULTS: The study was stopped after a planned interim analysis at the time of 520 deaths. The median overall survival was 18.4 months (95% confidence interval [CI], 17.3 to not yet reached) in the enzalutamide group versus 13.6 months (95% CI, 11.3 to 15.8) in the placebo group (hazard ratio for death in the enzalutamide group, 0.63; 95% CI, 0.53 to 0.75; P<0.001). The superiority of enzalutamide over placebo was shown with respect to all secondary end points: the proportion of patients with a reduction in the prostate-specific antigen (PSA) level by 50% or more (54% vs. 2%, P<0.001), the soft-tissue response rate (29% vs. 4%, P<0.001), the quality-of-life response rate (43% vs. 18%, P<0.001), the time to PSA progression (8.3 vs. 3.0 months; hazard ratio, 0.25; P<0.001), radiographic progression-free survival (8.3 vs. 2.9 months; hazard ratio, 0.40; P<0.001), and the time to the first skeletal-related event (16.7 vs. 13.3 months; hazard ratio, 0.69; P<0.001). Rates of fatigue, diarrhea, and hot flashes were higher in the enzalutamide group. Seizures were reported in five patients (0.6%) receiving enzalutamide. CONCLUSIONS: Enzalutamide significantly prolonged the survival of men with metastatic castration-resistant prostate cancer after chemotherapy. (Funded by Medivation and Astellas Pharma Global Development; AFFIRM ClinicalTrials.gov number, NCT00974311.)
Hadron Polarizabilities and Form Factors
This is the summary of the working group on Hadron Polarizabilities and Form
Factors of the Chiral Dynamics Workshop in Mainz, September 1-5, 1997.Comment: 21 pages LaTeX2e, uses epsf, 9 fig
Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II. Determination of, and results for, the pion form factor
The charged pion form factor, Fpi(Q^2), is an important quantity which can be
used to advance our knowledge of hadronic structure. However, the extraction of
Fpi from data requires a model of the 1H(e,e'pi+)n reaction, and thus is
inherently model dependent. Therefore, a detailed description of the extraction
of the charged pion form factor from electroproduction data obtained recently
at Jefferson Lab is presented, with particular focus given to the dominant
uncertainties in this procedure. Results for Fpi are presented for
Q^2=0.60-2.45 GeV^2. Above Q^2=1.5 GeV^2, the Fpi values are systematically
below the monopole parameterization that describes the low Q^2 data used to
determine the pion charge radius. The pion form factor can be calculated in a
wide variety of theoretical approaches, and the experimental results are
compared to a number of calculations. This comparison is helpful in
understanding the role of soft versus hard contributions to hadronic structure
in the intermediate Q^2 regime.Comment: 18 pages, 11 figure
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