10,252 research outputs found
Book Excerpt: \u3cem\u3eThe Guns of Normandy: A Soldier’s Eye View of France\u3c/em\u3e
Editor’s Note: Everyone who studies the land battles of the Second World War knows that artillery was the principle weapon employed by the Allied armies, but the gunners rarely receive the attention they deserve in narratives of the campaign. George Blackburn has written a book, The Guns of Normandy which restores the gunners to their rightful place. CMH is proud to publish two chapters from this book to announce that our Autumn issue will include an excerption from Mr. Blackburn’s forthcoming sequel. Chapter 15 takes up the story on 12 July 1944 as 4th Field Regiment is committed to support 4th Canadian Infantry Brigade west of Caen
Nonlinear Breit-Wheeler pair creation with bremsstrahlung rays
Electron-positron pairs are produced through the Breit-Wheeler process when
energetic photons traverse electromagnetic fields of sufficient strength. Here
we consider a possible experimental geometry for observation of pair creation
in the highly nonlinear regime, in which bremsstrahlung of an ultrarelativistic
electron beam in a high- target is used to produce rays that
collide with a counterpropagating laser pulse. We show how the target thickness
may be chosen to optimize the yield of Breit-Wheeler positrons, and verify our
analytical predictions with simulations of the cascade in the material and in
the laser pulse. The electron beam energy and laser intensity required are well
within the capability of today's high-intensity laser facilities.Comment: 12 pages, 5 figure
Arthur Cotton and Irrigation in Tasmania, 1839-43
Cotton, an officer of the East India Company with experience of irrigation, visited Tasmania for periods totalling three years. His influence was important in gaining acceptance of irrigation as an aid to cereal production and the livestock industry. Details are given of his Tasmanian work, which had particular significance there for its emphasis on water conservation
Low energy electron scattering from DNA and RNA bases: shape resonances and radiation damage
Calculations are carried out to determine elastic scattering cross sections
and resonance energies for low energy electron impact on uracil and on each of
the DNA bases (thymine, cytosine, adenine, guanine), for isolated molecules in
their equilibrium geometry. Our calculations are compared with available theory
and experiment. We also attempt to correlate this information with experimental
dissociation patterns through an analysis of the temporary anion structures
that are formed by electron capture in shape resonances.Comment: 20 pages, 12 figures, submitted to J. Chem. Phy
Chemoprevention with the metabolism modifying drugs dichloroacetate and metformin in the Li-Fraumeni Syndrome model, Trp53+/- mice
BACKGROUND:
While genetic testing for familial cancer has excelled, the
prevention options for those carrying high risk alleles have
not. Altered bioenergetics is now acknowledged as a hallmark
of cancer, and several very safe drugs are available
that can target this phentoype. Dichloroacetate (DCA)
inactivates pyruvate dehydrogenase kinase, resulting in
activation of pyruvate dehydrogenase, reduced lactic acid
production and increased mitochondrial activity. Metformin,
a type 2 diabetes treatment which activates AMPK,
thereby inhibiting mTOR, has unambiguously been
demonstrated to reduce the risk of many cancer types in
diabetics. We have tested these drugs as chemopreventive
agents against the mammary tumours that occur in the
BALB/c-Trp53+/- mouse spontaneous tumour model.
MATERIALS and METHODS
Breast cancer cell lines were examined for cell viability
after DCA and/or metformin treatment in vitro (neutral
red uptake assay). Four groups of female BALB/c-Trp53+/-
mice were given distilled water (n=75), DCA (1.5 g/L in
drinking water, ~180 mg/ kg/day, n=53), metformin (0.25
g/L in drinking water, ~30 mg/kg/day, n=61) or DCA
+metformin (n=51) from 8 weeks of age, and monitored
for tumour development over 78 weeks, and Kaplan-Meier
survival analysis was performed.
RESULTS
In vitro, DCA (1-5 mM) and metformin (30-300 uM),
alone or combined, significantly inhibited breast cancer
cell growth. In vivo, the overall tumour-free survival curves
for BALB/c-Trp53+/- mice were not significantly different between treatment groups, suggesting that metformin
does not reduce cancer risk in non-diabetics. However,
analysis of mammary tumours alone found that DCA
reduced the number and increased their latency (28.0% vs
20.8% of mice with mean latency of 55.0 vs 63.8 weeks,
untreated vs DCA respectively), whereas metformin had
no effect (26.2% of mice, mean latency 54.7 weeks). DCA
appeared to eliminate the early onset mammary tumours
(latency <52 weeks, p=0.02), while not affecting the occurrence
of longer latency tumours. In contrast, the two drug
combination had worse outcomes for tumour development,
(35.3% of mice, latency 48.8 weeks, p<0.02 compared
to DCA alone). Preliminary western blotting results
in MDA-MB-468 breast cancer cells found that DCA
could block the activation of AMPK by metformin, indicating
the potential for drug interactions.Supported by NHMRC Career Development Award, National Breast Cancer Foundation Novel Concept Award, and Cancer Australia
Content Based Retrieval and Navigation of Music
Contents 1 Introduction ................................................... 3 2 Literature Review .............................................. 4 2.1 Navigation ............................................... 4 2.2 Navigation of audio ........................................ 4 2.3 Contentrepresentations ..................................... 5 2.3.1 The musical score ................................... 6 2.3.2 Performance data .................................... 6 2.3.3 Musical pitch contours ................................ 6 2.3.4 Alternative representations ............................ 7 2.3.5 The Fourier transform ................................ 7 2.4 Content based retrieval ..................................... 8 2.4.1 Retrieval of digital audio samples ....................... 8 2.4.2 Query by humming .................................. 8 2.4.3 Lemstrm and Laine ................................. 9 2.4.4 Image matching techni
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