1,146 research outputs found
Observations on the potato during seasons 1928-29
The basis of the writer's work is included in The Potato.
In several directions further investigations have been made,
those for 1927 being presented in the Supplement.Newer work done during 1928-29 is reported briefly in the
succeeding pages.Previous observations, recorded in Chapters IV., VI., VII.,
and VIII. of The Potato, have been systematically checked for
old varieties and extended to include the many new varieties
which are coming on to the market. Several new characters
which promised to be useful in the discrimination of varieties
were subjected to a critical study in the field; and records
were made of other characters which are significant, though, in
some instances, less useful for field work.The procedure adopted throughout 1928 was that outlined on
pages 4, 5 and 6 of the Supplement, but in order to secure
greater accuracy all observations were verified during the summer
months by the writer and also independently by his assistant.A detailed and comprehensive discussion of the observations
made is considered unnecessary as the majority of them
will most probably be published in due course by the Department
of Agriculture for Scotland in Miscellaneous Publications, No. 3.
special attention will be directed, however, to such
characters as have not yet been reported in published papers
and books
Two-fluid matter-quintessence FLRW models: energy transfer and the equation of state of the universe
Recent observations support the view that the universe is described by a FLRW
model with , , and at the present epoch. There are several theoretical suggestions for
the cosmological component and for the particular form of the energy
transfer between this dark energy and matter. This gives a strong motive for a
systematic study of general properties of two-fluid FLRW models. We consider a
combination of one perfect fluid, which is quintessence with negative pressure
(), and another perfect fluid, which is a mixture of
radiation and/or matter components with positive pressure (), which define the associated one-fluid model (). We introduce a useful classification which contains 4 classes of
models defined by the presence or absence of energy transfer and by the
stationarity ( and ) or/and non stationarity (
or time dependent) of the equations of state. It is shown that, for
given and , the energy transfer defines and, therefore, the
total gravitating mass and dynamics of the model. We study important examples
of two-fluid FLRW models within the new classification. The behaviour of the
energy content, gravitating mass, pressure, and the energy transfer are given
as functions of the scale factor. We point out three characteristic scales,
, and , which separate periods of time in which
quintessence energy, pressure and gravitating mass dominate. Each sequence of
the scales defines one of 6 evolution types
Other Challenges in the Development of the Orbiter Environmental Control Hardware
Development of the Space Shuttle orbiter environmental control and life support system (ECLSS) included the identification and resolution of several interesting problems in several systems. Some of these problems occurred late in the program, including the flight phase. Problems and solutions related to the ammonia boiler system (ABS), smoke detector, water/hydrogen separator, and waste collector system (WCS) are addressed
Stability enhancing N-Terminal PEGylation of oxytocin exploiting different polymer architectures and conjugation approaches
Oxytocin, a cyclic nine amino acid neurohypophyseal hormone therapeutic, is effectively used in the control of postpartum hemorrhaging (PPH) and is on the WHO List of Essential Medicines. However, oxytocin has limited shelf life stability in aqueous solutions, particularly at temperatures in excess of 25 °C and injectable aqueous oxytocin formulations require refrigeration (<8 °C). This is particularly problematic in the hot climates often found in many developing countries where daytime temperatures can exceed 40 °C and where reliable cold-chain storage is not always achievable. The purpose of this study was to develop N-terminal amine targeted PEGylation strategies utilizing both linear PEG and polyPEG “comb” polymers as an effective method for stabilizing solution formulations of this peptide for prolonged storage in the absence of efficient cold-chain storage. The conjugation chemistries investigated herein include irreversible amine targeted conjugation methods utilizing NHS ester and aldehyde reductive amination chemistry. Additionally, one reversible conjugation method using a Schiff base approach was explored to allow for the release of the native peptide, thus, ensuring that biological activity remains unaffected. The reversibility of this approach was investigated for the different polymer architectures, alongside a nonpolymer oxytocin analogue to monitor how pH can tune native peptide release. Elevated temperature degradation studies of the polymer conjugates were evaluated to assess the stability of the PEGylated analogues in comparison to the native peptide in aqueous formulations to mimic storage conditions in developing nations and regions where storage under appropriate conditions is challenging
Neutron diffraction reveals sequence-specific membrane insertion of pre-fibrillar islet amyloid polypeptide and inhibition by rifampicin
AbstractHuman islet amyloid polypeptide (hIAPP) forms amyloid deposits in non-insulin-dependent diabetes mellitus (NIDDM). Pre-fibrillar hIAPP oligomers (in contrast to monomeric IAPP or mature fibrils) increase membrane permeability, suggesting an important role in the disease. In the first structural study of membrane-associated hIAPP, lamellar neutron diffraction shows that oligomeric hIAPP inserts into phospholipid bilayers, and extends across the membrane. Rifampicin, which inhibits hIAPP-induced membrane permeabilisation in functional studies, prevents membrane insertion. In contrast, rat IAPP (84% identical to hIAPP, but non-amyloidogenic) does not insert into bilayers. Our findings are consistent with the hypothesis that membrane-active pre-fibrillar hIAPP oligomers insert into beta cell membranes in NIDDM
Consensus Head Acceleration Measurement Practices (CHAMP): Origins, methods, transparency and disclosure
The use of head kinematic measurement devices has recently proliferated owing to technology advances that make such measurement more feasible. In parallel, demand to understand the biomechanics of head impacts and injury in sports and the military has increased as the burden of such loading on the brain has received focused attention. As a result, the field has matured to the point of needing methodological guidelines to improve the rigor and consistency of research and reduce the risk of scientific bias. To this end, a diverse group of scientists undertook a comprehensive effort to define current best practices in head kinematic measurement, culminating in a series of manuscripts outlining consensus methodologies and companion summary statements. Summary statements were discussed, revised, and voted upon at the Consensus Head Acceleration Measurement Practices (CHAMP) Conference in March 2022. This manuscript summarizes the motivation and methods of the consensus process and introduces recommended reporting checklists to be used to increase transparency and rigor of future experimental design and publication of work in this field. The checklists provide an accessible means for researchers to apply the best practices summarized in the companion manuscripts when reporting studies utilizing head kinematic measurement in sport and military settings
Inclusive School Community: Why is it so Complex?
This paper addresses the question: why is it so hard for school communities to respond to diversity in learners, staff and parents in inclusive ways? The authors draw on theory and recent professional experience in Queensland, Australia, to offer four guiding principles that address traditional assumptions about learning that result in inequality of opportunity and outcomes for students. The authors suggest these principles to support the development of a more inclusive school community: (1) develop a learning community incorporating a critical friend; (2) value and collaborate with parents and the broader community; (3) engage students as citizens in school review and develop¬ment; and (4) support teachers’ critical engagement with inclusive ideals and practices. The authors describe how the principles can work in concert in a school community
Prefrontal cortex gyrification index in twins: an MRI study
Cortical development and folding seems to be under environmental as well as genetic control. The aim of our study was to estimate the genetic influence on gyrification and cortical volumes, comparing prefrontal gyrification index (GI) in monozygotic (MZ) and dizygotic (DZ) twin pairs, and unrelated pairs. Twenty-four subjects (6 pairs of MZ and 6 pairs of DZ twins) were included in this study. Prefrontal cortical folding (gyrification) was measured by an automated and manual version of the gyrification index (A-GI, M-GI) according to previously published protocols. MR-imaging was performed and 3 representative slices were selected from coronar MR-imaging scans. The volumes of the total brain, temporal lobes, prefrontal lobes, and cerebellum were analyzed, too. To evaluate similarity in GI, absolute differences in GI, and brain volumes as well as intraclass correlations of twin pairs were compared with regard to twin status. Finally, a control group of unrelated pairs was assembled from the first two study groups and analyzed. Compared to unrelated pairs, twin pairs exhibited more similarity concerning different brain volumes and a trend to more similarity concerning A-GI. MZ twins did not present more similarity concerning GI (automatically and manually measured) and volume measurements compared to DZ twins. Different factors, like intrauterine factors, postnatal development conditions, and especially environmental factors might account for the differences between related and unrelated pairs. The nonexistence of a pronounced similarity in MZ twins compared to DZ twins concerning prefrontal GI raises questions about the extent of genetic influence on GI
Contextualised approaches to widening participation: a comparative case study of two UK universities
This article reports on institutional research at two contrasting UK universities, each with different foci in relation to widening participation (WP). The researchers sought to explore senior staff perspectives on the WP agenda at a time of unprecedented uncertainty and turmoil in the UK higher education sector. The research consisted primarily of interview data from university leaders responsible strategically for WP activity. The findings offer a nuanced narrative of the policy and practice of widening participation at two contrasting universities. Researchers found that the WP discourse itself is perceived as confused and discredited. Viewing ‘widening participation students’ as a homogenised group risks both the benefits of differentiated responses through discipline or subject areas and the benefits of more student-centred measures of success
Evolution of the Color-Magnitude Relation in Galaxy Clusters at z ~1 from the ACS Intermediate Redshift Cluster Survey
We apply detailed observations of the Color-Magnitude Relation (CMR) with the
ACS/HST to study galaxy evolution in eight clusters at z~1. The early-type red
sequence is well defined and elliptical and lenticular galaxies lie on similar
CMRs. We analyze CMR parameters as a function of redshift, galaxy properties
and cluster mass. For bright galaxies (M_B < -21mag), the CMR scatter of the
elliptical population in cluster cores is smaller than that of the S0
population, although the two become similar at faint magnitudes. While the
bright S0 population consistently shows larger scatter than the ellipticals,
the scatter of the latter increases in the peripheral cluster regions. If we
interpret these results as due to age differences, bright elliptical galaxies
in cluster cores are on average older than S0 galaxies and peripheral
elliptical galaxies (by about 0.5Gyr). CMR zero point, slope, and scatter in
the (U-B)_z=0 rest-frame show no significant evolution out to redshift z~1.3
nor significant dependence on cluster mass. Two of our clusters display CMR
zero points that are redder (by ~2sigma) than the average (U-B)_z=0 of our
sample. We also analyze the fraction of morphological early-type and late-type
galaxies on the red sequence. We find that, while in the majority of the
clusters most (80% to 90%) of the CMR population is composed of early-type
galaxies, in the highest redshift, low mass cluster of our sample, the CMR
late-type/early-type fractions are similar (~50%), with most of the late-type
population composed of galaxies classified as S0/a. This trend is not
correlated with the cluster's X-ray luminosity, nor with its velocity
dispersion, and could be a real evolution with redshift.Comment: ApJ, in press, 27 pages, 22 figure
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