Muskrats on tidal marshes of Dorchester County

This bulletin reports, in a non-technical manner, investigations on the Virginia muskrat, prevalent in Maryland, from July, 1949 to June, 1951

Report on the Bombing of Our Own Troops during Operation “Tractable”: 14 August 1944

Editor’s Note: Operation “Tractable“ was the second major Canadian operation in Normandy designed to break through the German defensive perimeter to reach Falaise. Like its predecessor, Operation “Totalize,“ “Tractable“ was to employ heavy bombers to augment the firepower available to the troops. The use of heavy bombers in a tactical role was a relatively new tasking for the strategic force and required precise targetting to destroy and disrupt enemy positions. The strategic bomber force, British and American, had made significant contributions to the land battle in Normandy, but there had been mistakes, most notably during Operation “Cobra” when the American 8th Air Force had twice bombed their own troops on 24–25 July causing 136 deaths and an additional 621 casualties. For Operation “Tractable,” the medium bombers of 2 Group, 2nd Tactical Air Force were to bomb German gun, mortar and tank positions along the startline immediately prior to H-Hour. This was to be followed by a large attack by Bomber Command hours after the start of the advance. This bombing was intended “to destroy or neutralize enemy guns, harbours, and defended lacalities on the right flank and to prevent any enemy movement from this area to the area of attack.” (First Canadian Army Op Instruction No. 14, August 1944). Though the air support was largely a success, a number of aircraft mistakenly bombed short hitting units of First Canadian Army. In total, over 150 Allied soldiers were killed and 241 wounded by the short bombing. Though it had little impact on the outcome of “Tractable,” there were a number of investigations launched to understand why the short bombing occurred. The report which follows, dated 25 August 1944 and written by Air Chief Marshal Arthur Harris, Air Officer Commanding-in-Chief of Bomber Command, contains the official RAF post–mortem on the reasons for the accidental bombing of First Canadian Army

Computer used to program numerically controlled milling machine

Computer program automatically directs a numerically controlled milling machine through a series of cutting and trimming actions. It accepts engineering data points, passes smooth curve segments through the points, breaks the resulting curves into a series of closely spaced points, and transforms these points into the form required by the mechanism

”I Speak Hip Hop”: An Informative Interview about Generation Hip Hop and the Universal Hip Hop Museum

”I Speak Hip Hop” is an interview of members of Generation Hip Hop and the Universal Hip Hop Museum. This primary source highlights two Hip Hop organizations with chapters around the world. Tasha Iglesias and Travis Harris posits that Hip Hop scholars have not fully uncovered Hip Hop\u27s history around the world. As such, in addition to being a primary source, I Speak Hip Hop reveals the need for more scholarly attention on the dynamic expansion of Hip Hop cultures

Demographic fluctuations in a population of anomalously diffusing individuals

The phenomenon of spatial clustering induced by death and reproduction in a population of anomalously diffusing individuals is studied analytically. The possibility of social behaviors affecting the migration strategies has been taken into exam, in the case anomalous diffusion is produced by means of a continuous time random walk (CTRW). In the case of independently diffusing individuals, the dynamics appears to coincide with that of (dying and reproducing) Brownian walkers. In the strongly social case, the dynamics coincides with that of non-migrating individuals. In both limits, the growth rate of the fluctuations becomes independent of the Hurst exponent of the CTRW. The social behaviors that arise when transport in a population is induced by a spatial distribution of random traps, have been analyzed.Comment: 10 pages, 6 figure

Look right! A retrospective study of pedestrian accidents involving overseas visitors to London

Introduction: Research within the European Union has shown international visitors to have a higher injury mortality than residents. Traffic accidents are the leading cause of injury-related death among overseas visitors and evidence suggests overseas visitors are at a greater risk of being involved in road traffic accidents than the resident population. Little information looks specifically at pedestrian injuries to overseas visitors. Pedestrian deaths account for 21% of all UK road deaths. Methods: A retrospective database review of London helicopter emergency medical service (HEMS) missions was undertaken to examine the number and type of missions to overseas visitors, specifically examining pedestrian incidents. Results: Of 121 missions to overseas visitors, 74 (61%) involved the visitor as a pedestrian struck by a vehicle. Thirty-five pedestrians (47%) were struck by a bus and 20 by a car (27%). Fourteen patients (19%) had an initial Glasgow coma scale score of 3–8, suggesting severe head injury and half of all patients required prehospital intubation (38/74, 51%). Mortality was 16% (12/74%) and 62 patients (84%) survived to hospital discharge. Of 39 patients admitted to the Royal London Hospital, the average injury severity score (ISS%) was 23.0 (ISS >15 denotes severe trauma) with a mean inpatient stay of 17.9 days. Conclusion: During the 7-year period studied, 61% of HEMS missions to overseas visitors involved a pedestrian being struck by a vehicle, compared with 16% of missions to UK residents. For HEMS missions, serious trauma to pedestrians is disproportionally more common among the visitor population to London

Introduction: Ain’t It Evil to Live Backwards? : A Hip Hop Perspective of Religion

Historically, Black religion has been the cornerstone of the African experience in America. Due to the peculiar institution” of slavery and the ways this institutional residue still affect the lives of slave descendants, Hip Hop provides a forum to simultaneously acknowledge similarities and highlight differences. What scholars of religion and Hip Hop studies have revealed are the ways in which the effectiveness and our very understanding of “religion” changes when we bring Hip Hop in to the mix

Ab initio quantum dynamics using coupled-cluster

The curse of dimensionality (COD) limits the current state-of-the-art {\it ab initio} propagation methods for non-relativistic quantum mechanics to relatively few particles. For stationary structure calculations, the coupled-cluster (CC) method overcomes the COD in the sense that the method scales polynomially with the number of particles while still being size-consistent and extensive. We generalize the CC method to the time domain while allowing the single-particle functions to vary in an adaptive fashion as well, thereby creating a highly flexible, polynomially scaling approximation to the time-dependent Schr\"odinger equation. The method inherits size-consistency and extensivity from the CC method. The method is dubbed orbital-adaptive time-dependent coupled-cluster (OATDCC), and is a hierarchy of approximations to the now standard multi-configurational time-dependent Hartree method for fermions. A numerical experiment is also given.Comment: 5 figure

Fourier's law on a one-dimensional optical random lattice

We study the transport properties of a one-dimensional hard-core bosonic lattice gas coupled to two particle reservoirs at different chemical potentials which generate a current flow through the system. In particular, the influence of random fluctuations of the underlying lattice on the stationary-state properties is investigated. We show analytically that the steady-state density presents a linear profile. The local steady-state current obeys the Fourier law $j=-\kappa(\tau)\nabla n$ where $\tau$ is a typical timescale of the lattice fluctuations and $\nabla n$ the density gradient imposed by the reservoirs.Comment: 9 pages, 2 figure

Study of sample drilling techniques for Mars sample return missions

To demonstrate the feasibility of acquiring various surface samples for a Mars sample return mission the following tasks were performed: (1) design of a Mars rover-mounted drill system capable of acquiring crystalline rock cores; prediction of performance, mass, and power requirements for various size systems, and the generation of engineering drawings; (2) performance of simulated permafrost coring tests using a residual Apollo lunar surface drill, (3) design of a rock breaker system which can be used to produce small samples of rock chips from rocks which are too large to return to Earth, but too small to be cored with the Rover-mounted drill; (4)design of sample containers for the selected regolith cores, rock cores, and small particulate or rock samples; and (5) design of sample handling and transfer techniques which will be required through all phase of sample acquisition, processing, and stowage on-board the Earth return vehicle. A preliminary design of a light-weight Rover-mounted sampling scoop was also developed