30,213 research outputs found
Thermodielectric radiometer
Radiometer measures microsecond pulses of radiant flux in the presence of electromagnetic noise. It consists of a charged capacitor that delivers a voltage pulse proportional to the thermally induced depolarization of its polymeric dielectric
Comparison of data on Mutation Frequencies of Mice Caused by Radiation - Low Dose Model -
We propose LD(Low Dose) model, the extension of LDM model which was proposed
in the previous paper [Y. Manabe et al.: J. Phys. Soc. Jpn. 81 (2012) 104004]
to estimate biological damage caused by irradiation. LD model takes account of
all the considerable effects including cell death effect as well as
proliferation, apoptosis, repair. As a typical example of estimation, we apply
LD model to the experiment of mutation frequency on the responses induced by
the exposure to low levels of ionizing radiation. The most famous and extensive
experiments are those summarized by Russell and Kelly [Russell, W. L. & Kelly,
E. M: Proc. Natl Acad. Sci. USA 79 (1982) 539-541], which are known as
'Mega-mouse project'. This provides us with important information of the
frequencies of transmitted specific-locus mutations induced in mouse
spermatogonia stem-cells. It is found that the numerical results of the
mutation frequency of mice are in reasonable agreement with the experimental
data: the LD model reproduces the total dose and dose rate dependence of data
reasonably. In order to see such dose-rate dependence more explicitly, we
introduce the dose-rate effectiveness factor (DREF). This represents a sort of
preventable effects such as repair, apoptosis and death of broken cells, which
are to be competitive with proliferation effect of broken cells induced by
irradiation.Comment: subimitting to J. Phys. Soc. Jpn, 32 pages, 8 figure
Experience with a vectorized general circulation weather model on Star-100
A version of an atmospheric general circulation model was vectorized to run on a CDC STAR 100. The numerical model was coded and run in two different vector languages, CDC and LRLTRAN. A factor of 10 speed improvement over an IBM 360/95 was realized. Efficient use of the STAR machine required some redesigning of algorithms and logic. This precludes the application of vectorizing compilers on the original scalar code to achieve the same results. Vector languages permit a more natural and efficient formulation for such numerical codes
Spectroscopic binaries with elliptical orbits
The radial velocity curves of many spectroscopic binaries (SBs) are perturbed
by gas streams or proximity effects. For SBs with circular orbits, these
perturbations can give rise to spurious orbital eccentricities of high
statistical significance. But tests to identify such anomalous orbits can be
constructed since perturbed velocity curves are in general no longer Keplerian.
The derived tests are applied both to synthetic and to observed velocity
curves.Comment: 9pages,3figures,accepted by A&
An Ethical Framework for Visitation of Inpatients Receiving Palliative Care in the COVID-19 Context.
Human connection is universally important, particularly in the context of serious illness and at the end of life. The presence of close family and friends has many benefits when death is close. Hospital visitation restrictions during the Coronavirus (COVID-19) pandemic therefore warrant careful consideration to ensure equity, proportionality, and the minimization of harm. The Australian and New Zealand Society for Palliative Medicine COVID-19 Special Interest Group utilized the relevant ethical and public health principles, together with the existing disease outbreak literature and evolving COVID-19 knowledge, to generate a practical framework of visiting restrictions for inpatients receiving palliative and end-of-life care. Expert advice from an Infectious Diseases physician ensured relevance to community transmission dynamics. Three graded levels of visitor restrictions for inpatient settings are proposed, defining an appropriate level of minimum access. These depend upon the level of community transmission of COVID-19, the demand on health services, the potential COVID-19 status of the patient and visitors, and the imminence of the patient's death. This framework represents a cohesive, considered, proportionate, and ethically robust approach to improve equity and consistency for inpatients receiving palliative care during the COVID-19 pandemic and may serve as a template for future disease outbreaks
Heat of Wetting of Soils
Many important soil processes such as base exchange capacity, plant food availability and moisture holding capacity, are influenced by the amount of surface per unit mass of soil. For this reason, measurements related to this soil characteristic may be used in connection with many soil problems. This article is concerned with the description of a method of measuring the relative surface area of soils with apparatus suited for student use. It consists in measuring the heat energy liberated by a dry soil which is wetted by water at the same temperature
Recovering a lost baseline: missing kelp forests from a metropolitan coast
© 2008 AuthorThere is concern about historical and continuing loss of canopy-forming algae across the world’s temperate coastline. In South Australia, the sparse cover of canopy-forming algae on the Adelaide metropolitan coast has been of public concern with continuous years of anecdotal evidence culminating in 2 competing views. One view considers that current patterns existed before the onset of urbanisation, whereas the alternate view is that they developed after urbanisation. We tested hypotheses to distinguish between these 2 models, each centred on the reconstruction of historical covers of canopies on the metropolitan coast. Historically, the metropolitan sites were indistinguishable from contemporary populations of reference sites across 70 km (i.e. Gulf St. Vincent), and could also represent a random subset of exposed coastal sites across 2100 km of the greater biogeographic province. Thus there was nothing ‘special’ about the metropolitan sites historically, but today they stand out because they have sparser covers of canopies compared to equivalent locations and times in the gulf and the greater province. This is evidence of wholesale loss of canopy-forming algae (up to 70%) on parts of the Adelaide metropolitan coast since major urbanisation. These findings not only set a research agenda based on the magnitude of loss, but they also bring into question the logic that smaller metropolitan populations of humans create impacts that are trivial relative to that of larger metropolitan centres. Instead, we highlight a need to recognise the ecological context that makes some coastal systems more vulnerable or resistant to increasing human-domination of the world’s coastlines. We discuss challenges to this kind of research that receive little ecological discussion, particularly better leadership and administration, recognising that the systems we study out-live the life spans of individual research groups and operate on spatial scales that exceed the capacity of single research providers.Sean D. Connell, Bayden D. Russell, David J. Turner, Scoresby A. Shepherd, Timothy Kildea, David Miller, Laura Airoldi, Anthony Cheshir
- …