199 research outputs found
Effect of a mixture of caffeine and nicotinamide on the solubility of vitamin (B2) in aqueous solution
The effect of caffeine (CAF) and nicotinamide (NMD) on the solubility of a vitamin B2 derivative (FMN) has been evaluated for mixtures containing either a single hydrotrope (CAF or NMD) or the two hydrotropes simultaneously. A model for analysis of ternary systems, which takes into account all possible complexes between the molecules, has been developed and tested with experimental NMR data on the three-component mixture FMN–CAF–NMD. The results indicate that special attention should be given to the concentration of a hydrotropic agent used to enhance the solubility of a particular drug. A decrease in the efficacy of solubility of the vitamin on addition of large amounts of hydrotropic agent is expected in the two-component systems due to the increased proportion of self-association of the hydrotrope. It is found that a mixture of two hydrotropic agents leads to an increase in the solubility of the vitamin in three-component compared to the two-component system. Rather than using just one hydrotropic agent, it is proposed that a strategy for optimising the solubility of aromatic drugs is to use a mixture of hydrotropic agents
Climate Services for Resilient Development in South Asia and Bangladesh: Semi-Annual and Inception Period Report April 2017
Developing countries are at considerable risk from climate variability and climate change, both of which threaten poverty reduction and development efforts. The Climate Services for Resilient Development (CSRD) partnership is led by the United States Government has developed a consortium of global leaders in science, technology and development finance to assist at-risk nations to adapt to these problems. CSRD is aligned with the the Global Framework for Climate Services and works in Bangladesh, Ethiopia, and Colombia to creating and provide timely and useful climate data, information, tools, and services.
Within South Asia, efforts to develop agricultural climate services under CSRD are led by the International Maize and Wheat Improvement Center (CIMMYT). CSRD in turn works to support Investment Options Paper (IOP) for Climate Services for Resilient Development in Bangladesh, compiled by the Asian Development Bank (ADB) in 2016. CSRD’s core objectives are to prepare farmers, extension services, and agricultural policy makers with actionable climate information and crop management advisories to reduce agricultural production risks and to increase the resilience of smallholder farming communities. This report summarizes CSRD activities, achievements, and challenges during the project’s inception phase (from the end of November 2017 through April of 2017)
Survey of the impact of COVID-19 on oncologists’ decision making in cancer
PURPOSE
To understand readiness measures taken by oncologists to protect patients and health care workers from the novel coronavirus (COVID-19) and how their clinical decision making was influenced by the pandemic.
METHODS
An online survey was conducted between March 24 and April 29, 2020.
RESULTS
A total of 343 oncologists from 28 countries participated. The median age was 43 years (range, 29-68 years), and the majority were male (62%). At the time of the survey, nearly all participants self-reported an outbreak in their country (99.7%). Personal protective equipment was available to all participants, of which surgical mask was the most common (n = 308; 90%). Telemedicine, in the form of phone or video encounters, was common and implemented by 80% (n = 273). Testing patients with cancer for COVID-19 via reverse transcriptase polymerase chain reaction before systemic treatment was not routinely implemented: 58% reported no routine testing, 39% performed testing in selected patients, and 3% performed systematic testing in all patients. The most significant factors influencing an oncologist’s decision making regarding choice of systemic therapy included patient age and comorbidities (81% and 92%, respectively). Although hormonal treatments and tyrosine kinase inhibitors were considered to be relatively safe, cytotoxic chemotherapy and immune therapies were perceived as being less safe or unsafe by participants. The vast majority of participants stated that during the pandemic they would use less chemotherapy, immune checkpoint inhibitors, and steroids. Although treatment in neoadjuvant, adjuvant, and first-line metastatic disease was less affected, most of the participants stated that they would be more hesitant to recommend second- or third-line therapies in metastatic disease.
CONCLUSION
Decision making by oncologists has been significantly influenced by the ongoing COVID-19 pandemic
Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter
Data collected by the Pierre Auger Observatory through 31 August 2007 showed
evidence for anisotropy in the arrival directions of cosmic rays above the
Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{eV}. The
anisotropy was measured by the fraction of arrival directions that are less
than from the position of an active galactic nucleus within 75 Mpc
(using the V\'eron-Cetty and V\'eron catalog). An updated
measurement of this fraction is reported here using the arrival directions of
cosmic rays recorded above the same energy threshold through 31 December 2009.
The number of arrival directions has increased from 27 to 69, allowing a more
precise measurement. The correlating fraction is , compared
with expected for isotropic cosmic rays. This is down from the early
estimate of . The enlarged set of arrival directions is
examined also in relation to other populations of nearby extragalactic objects:
galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in
hard X-rays by the Swift Burst Alert Telescope. A celestial region around the
position of the radiogalaxy Cen A has the largest excess of arrival directions
relative to isotropic expectations. The 2-point autocorrelation function is
shown for the enlarged set of arrival directions and compared to the isotropic
expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201
Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory
Atmospheric parameters, such as pressure (P), temperature (T) and density,
affect the development of extensive air showers initiated by energetic cosmic
rays. We have studied the impact of atmospheric variations on extensive air
showers by means of the surface detector of the Pierre Auger Observatory. The
rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find
that the observed behaviour is explained by a model including the effects
associated with the variations of pressure and density. The former affects the
longitudinal development of air showers while the latter influences the Moliere
radius and hence the lateral distribution of the shower particles. The model is
validated with full simulations of extensive air showers using atmospheric
profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle
Physic
The Fluorescence Detector of the Pierre Auger Observatory
The Pierre Auger Observatory is a hybrid detector for ultra-high energy
cosmic rays. It combines a surface array to measure secondary particles at
ground level together with a fluorescence detector to measure the development
of air showers in the atmosphere above the array. The fluorescence detector
comprises 24 large telescopes specialized for measuring the nitrogen
fluorescence caused by charged particles of cosmic ray air showers. In this
paper we describe the components of the fluorescence detector including its
optical system, the design of the camera, the electronics, and the systems for
relative and absolute calibration. We also discuss the operation and the
monitoring of the detector. Finally, we evaluate the detector performance and
precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics
Research Section
Advanced functionality for radio analysis in the Offline software framework of the Pierre Auger Observatory
The advent of the Auger Engineering Radio Array (AERA) necessitates the
development of a powerful framework for the analysis of radio measurements of
cosmic ray air showers. As AERA performs "radio-hybrid" measurements of air
shower radio emission in coincidence with the surface particle detectors and
fluorescence telescopes of the Pierre Auger Observatory, the radio analysis
functionality had to be incorporated in the existing hybrid analysis solutions
for fluoresence and surface detector data. This goal has been achieved in a
natural way by extending the existing Auger Offline software framework with
radio functionality. In this article, we lay out the design, highlights and
features of the radio extension implemented in the Auger Offline framework. Its
functionality has achieved a high degree of sophistication and offers advanced
features such as vectorial reconstruction of the electric field, advanced
signal processing algorithms, a transparent and efficient handling of FFTs, a
very detailed simulation of detector effects, and the read-in of multiple data
formats including data from various radio simulation codes. The source code of
this radio functionality can be made available to interested parties on
request.Comment: accepted for publication in NIM A, 13 pages, minor corrections to
author list and references in v
Search for First Harmonic Modulation in the Right Ascension Distribution of Cosmic Rays Detected at the Pierre Auger Observatory
We present the results of searches for dipolar-type anisotropies in different
energy ranges above eV with the surface detector array of
the Pierre Auger Observatory, reporting on both the phase and the amplitude
measurements of the first harmonic modulation in the right-ascension
distribution. Upper limits on the amplitudes are obtained, which provide the
most stringent bounds at present, being below 2% at 99% for EeV
energies. We also compare our results to those of previous experiments as well
as with some theoretical expectations.Comment: 28 pages, 11 figure
Upper limit on the cosmic-ray photon fraction at EeV energies from the Pierre Auger Observatory
From direct observations of the longitudinal development of ultra-high energy
air showers performed with the Pierre Auger Observatory, upper limits of 3.8%,
2.4%, 3.5% and 11.7% (at 95% c.l.) are obtained on the fraction of cosmic-ray
photons above 2, 3, 5 and 10 EeV (1 EeV = 10^18 eV) respectively. These are the
first experimental limits on ultra-high energy photons at energies below 10
EeV. The results complement previous constraints on top-down models from array
data and they reduce systematic uncertainties in the interpretation of shower
data in terms of primary flux, nuclear composition and proton-air
cross-section.Comment: 20 pages, 7 figures, 2 tables. Minor changes. Accepted by
Astroparticle Physic
- …