2,458 research outputs found
Tumour Incidence and Tumour-Free Sublines in BR6 Mice
IN 1945 Foulds mated some C57/BL female mice with RIII males. Some of the progeny of these matings developed mammary tumours and the sixth female to do so and a male of the same litter constituted the parents of the BR6 strain which has been maintained by brother-sister mating ever since. Foulds supposed that the BR6 strain harbours the mammary tumour virus derived from its RIII male progenitor since the virus was demonstrable in a similar C57 x RIII hybrid bearing mammary tumours (Foulds, 1949a). The tumour incidence in the strain was high from the start (Foulds, 1949a). The tumours are influenced greatly by hormonal conditions; many of them in the original hybrids were readily transplantable into female recipients of the same genetic constitution or into males treated with oestrogen but grew slowly after a long latent period, or not at all, in males (Foulds, 1947), though this sex factor in transplantation tended to be lost in subsequent generations (Foulds, 1949b). The most striking characteristic of the tumours in the BRG line was their pregnancy dependence. The tumours almost invariably first appeared during pregnancy
Bulgac-Kusnezov-Nos\'e-Hoover thermostats
In this paper we formulate Bulgac-Kusnezov constant temperature dynamics in
phase space by means of non-Hamiltonian brackets. Two generalized versions of
the dynamics are similarly defined: one where the Bulgac-Kusnezov demons are
globally controlled by means of a single additional Nos\'e variable, and
another where each demon is coupled to an independent Nos\'e-Hoover thermostat.
Numerically stable and efficient measure-preserving time-reversible algorithms
are derived in a systematic way for each case. The chaotic properties of the
different phase space flows are numerically illustrated through the
paradigmatic example of the one-dimensional harmonic oscillator. It is found
that, while the simple Bulgac-Kusnezov thermostat is apparently not ergodic,
both of the Nos\'e-Hoover controlled dynamics sample the canonical distribution
correctly
An analysis of the Research Fellowship Scheme of the Royal College of Surgeons of England.
BACKGROUND: The Research Fellowship Scheme of the Royal College of Surgeons of England commenced in 1993 with the aim of exposing selected surgical trainees to research techniques and methodology, with the hope of having an impact on surgical research and increasing the cadre of young surgeons who might decide to pursue an academic career in surgery. Over 11 million pounds sterling (approximately US 20 million dollars) has been invested in 264 fellowships. The College wished to evaluate the impact of the Scheme on the careers of research fellows, surgical research, and patient care. As the 10th anniversary of the Scheme approached. STUDY DESIGN: Two-hundred and sixty research fellows whose current addresses were available were sent a questionnaire. Two-hundred and thirty-eight (91.5%) responded. RESULTS: Three-quarters of the research fellows conducted laboratory-based research, with most of the remainder conducting patient-based clinical research. One-third of the fellows who have reached consultant status have an academic component to their post. The total number of publications based on fellowship projects was 531, with a median impact factor of 3.5. Almost all fellows had been awarded a higher degree or were working toward this. Half of the fellows received subsequent funding for research, mostly awarded by national or international funding bodies. CONCLUSIONS: The Research Fellowship Scheme of the Royal College of Surgeons of England has successfully supported many trainee surgeons in the initial phase of their research career. It has helped surgical research by increasing the pool of surgeons willing to embark on an academic career. Indirectly, patient care has benefited by promoting an evidence-based culture among young surgeons. Such schemes are relevant to surgical training programs elsewhere if more young surgeons are to be attracted into academic surgery
The myth of agency and the misattribution of blame in collective imaginaries of the future
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149565/1/bjos12662_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149565/2/bjos12662.pd
Recommended from our members
Heterogeneous processes at the intersection of chemistry and biology: A computational approach
Heterogeneous processes hold the key to understanding many problems in biology and atmospheric science. In particular, recent experiments have shown that heterogeneous chemistry at the surface of sea-salt aerosols plays a large role in important atmospheric processes with far reaching implications towards understanding of the fate and transport of aerosolized chemical weapons (i.e. organophosphates such as sarin and VX). Unfortunately, the precise mechanistic details of the simplest surface enhanced chemical reactions remain unknown. Understanding heterogeneous processes also has implications in the biological sciences. Traditionally, it is accepted that enzymes catalyze reactions by stabilizing the transition state, thereby lowering the free energy barrier. However, recent findings have shown that a multitude of phenomena likely contribute to the efficiency of enzymes, such as coupled protein motion, quantum mechanical tunneling, or strong electrostatic binding. The objective of this project was to develop and validate a single computational framework based on first principles simulations using tera-scale computational resources to answer fundamental scientific questions about heterogeneous chemical processes relevant to atmospheric chemistry and biological sciences
Educating law students for rural and regional legal practice: embedding place consciousness in law curricula
As with other professions, the declining rates of recruitment and retention of lawyers in rural and regional Australia is of significant concern. Whilst the causes of this vary between communities, common depictions of the rural and regional lawyer’s role indicate that employment as a lawyer in such areas is characterised by unique personal and professional challenges. Nonetheless, employment as a rural and regional lawyer also offers practitioners rewarding opportunities and lifestyle benefits. Research from other disciplines indicates that the challenges inherent in rural and regional professional practice may be alleviated, and benefits more easily harnessed, via place conscious discipline-specific curriculum that sensitises tertiary students to, and prepares them for, the rural and regional career context.Largely oriented towards substantive content to satisfy external accrediting bodies, undergraduate legal education does not typically acknowledge the ‘places’in which graduates will practice as professionals. This article argues however that there is scope to incorporate place within legal education, and documents an innovative curriculum development project which embeds place consciousness to better prepare law students for employment in rural and regional legal practice.Drawing upon methods from other disciplines, the project team designed a curriculum package which aims to sensitise students to the rural and regional legal practice context, and equip them with the skills to overcome challenges and take advantage of the opportunities available in a rural or regional professional career
Tracing the Mass during Low-Mass Star Formation. II. Modelling the Submillimeter Emission from Pre-Protostellar Cores
We have modeled the emission from dust in pre-protostellar cores, including a
self-consistent calculation of the temperature distribution for each input
density distribution. Model density distributions include Bonnor-Ebert spheres
and power laws. The Bonnor-Ebert spheres fit the data well for all three cores
we have modeled. The dust temperatures decline to very low values (\Td \sim 7
K) in the centers of these cores, strongly affecting the dust emission.
Compared to earlier models that assume constant dust temperatures, our models
indicate higher central densities and smaller regions of relatively constant
density. Indeed, for L1544, a power-law density distribution, similar to that
of a singular, isothermal sphere, cannot be ruled out. For the three sources
modeled herein, there seems to be a sequence of increasing central
condensation, from L1512 to L1689B to L1544. The two denser cores, L1689B and
L1544, have spectroscopic evidence for contraction, suggesting an evolutionary
sequence for pre-protostellar cores.Comment: 22 pages, 9 figures, Ap. J. accepted, uses emulateapj5.st
Content in fatty acids and carotenoids in phytoplankton blooms during the seasonal sea ice retreat in Hudson Bay complex, Canada.
The Hudson Bay complex (HBC) is home to numerous indigenous communities that traditionally have relied
heavily on its marine resources. The nutritional quality and stocks of the entire HBC food web depend in
large part on the phytoplankton production of bioactive molecules (long chain polyunsaturated fatty acids
and carotenoids) and their transfer through trophic levels. The purpose of this study was thus to
determine which molecules were produced during spring phytoplankton blooms, as well as the
environmental factors driving this production. We investigated 21 stations in 5 sub-regions of the HBC.
At the time of sampling, the sub-regions studied had different environmental settings (e.g., ice cover,
nutrients, seawater salinity and temperature) conditioning their bloom stages. Pre- and post-bloom stages
were associated with relatively low concentrations of bioactive molecules (either fatty acids or
carotenoids). In contrast, the highest concentrations of bioactive molecules (dominated by
eicosapentaenoic acid and fucoxanthin) were associated with the diatom bloom that typically occurs at
the ice edge when silicates remain available. Interestingly, the large riverine inputs in eastern Hudson Bay
led to a change in protist composition (larger contribution of Dinophyceae), resulting in lower while more
diverse content of bioactive molecules, whether fatty acids (e.g., aa-linolenic acid) or carotenoids
(e.g., peridinin). As greater stratification of the HBC is expected in the future, we suggest that
a mixotrophic/heterotrophic flagellate-based food web would become more prevalent, resulting in
a smaller supply of bioactive molecules for the food web
- …