bluuebunny/crossref_metadata_2025 huggingface dataset:
Mean-square and almost-sure convergence of supercritical age-dependent branching processes
Authors: Ganuza Edgar Z. , Durham S. D.
Published: July 2016

Letting Z(t) be the number of objects alive at time t in a general supercritical age-dependent branching process generated by a single ancestor born at time 0, one achieves (Theorem 1) mean-square convergence of Z(t)/E[Z(t)] provided and , where N(t) is the number of offspring of the initial ancestor born by time t and α is the (positive) Malthusian parameter defined by . If the stronger conditions that (Theorem 2) and hold also, then the convergence is almost-sure. It is of interest that the embedded Galton-Watson process of successive generations need not have a finite mean for the conditions of the above theorems to hold. Similar results are obtained for the age-distribution as well.
Estimation of the mean and the initial probabilities of a branching process
Authors: Dion Jean-Pierre
Published: July 2016

In this article, we consider maximum likelihood estimators of the initial probabilities and the mean of a supercritical Galton-Watson process; we find for these estimators, as well as for the Lotka-Nagaev estimator of the mean, the asymptotic distributions and deduce confidence intervals. As these results hold even if the independence between individuals of the same generation is not satisfied, application to living populations may be considered.
Quasi-stationary distributions for Markov chains on a general state space
Authors: Tweedie Richard. L.
Published: July 2016

The quasi-stationary behaviour of a Markov chain which is φ-irreducible when restricted to a subspace of a general state space is investigated. It is shown that previous work on the case where the subspace is finite or countably infinite can be extended to general chains, and the existence of certain quasi-stationary limits as honest distributions is equivalent to the restricted chain being R-positive with the unique R-invariant measure satisfying a certain finiteness condition.
Queues with random service output: the case of Poisson arrivals
Authors: Grinstein Jacob , Rubinovitch Michael
Published: July 2016

A general class of single server queueing models is formulated. They distinguish between two factors that may influence the duration of service times: variability in the service requirements of customers, and variability (over time) in the service output of the server. Accordingly, we assume that the demands for service of successive customers form a sequence of independent, identically distributed random variables and that the amount of service produced by a busy server in a time interval is determined by the increment of a process with stationary independent increments over that interval. The results include the distribution of the busy period and the limiting distribution of the queue length. We also investigate the potential waiting process which is an extension of virtual waiting time process in existing queueing models.
Limiting distributions for the general branching process with immigration
Authors: Durham S. D.
Published: July 2016

For the general age-dependent branching process subject to an arbitrary pattern of immigration asymptotic distributions are studied in the supercritical and critical cases. In the supercritical case a new functional form is given for the limiting cumulant-generating function and in the critical case moment conditions are given under which a randomized gamma limit law prevails. The age-structure is also considered.
Queues in transportation systems, I: a Markovian system
Authors: Crane Michael A.
Published: July 2016

We study a transportation system consisting of S vehicles of unit capacity and N passenger terminals. Customers arrive stochastically at terminal i, 1 ≦ i ≦ N, seeking transportation to a terminal j, 1 ≦ j ≦ N, with probability Pij
. Customers at each terminal are served as vehicles become available. Each vehicle is dispatched from a terminal when loaded, whereupon it travels to the destination of its passenger, according to a stochastic travel time. It is shown under mild conditions that the system is unstable, due to random fluctuations of independent customer arrival processes. We obtain limit theorems, in certain special cases, for the customer queue size processes. Where a steady-state limit exists, this limit is expressed in terms of the corresponding limit in a related GI/G/S queue. In other cases, functional central limit theorems are obtained for appropriately normalized random functions.
DEWORMING DELUSIONS? MASS DRUG ADMINISTRATION IN EAST AFRICAN SCHOOLS
Authors: Allen Tim , Parker Melissa
Published: July 2016

Recent debates about deworming school-aged children in East Africa have been described as the ‘Worm Wars’. The stakes are high. Deworming has become one of the top priorities in the fight against infectious diseases. Staff at the World Health Organization, the Gates Foundation and the World Bank (among other institutions) have endorsed the approach, and school-based treatments are a key component of large-scale mass drug administration programmes. Drawing on field research in Uganda and Tanzania, and engaging with both biological and social evidence, this article shows that assertions about the effects of school-based deworming are over-optimistic. The results of a much-cited study on deworming Kenyan school children, which has been used to promote the intervention, are flawed, and a systematic review of randomized controlled trials demonstrates that deworming is unlikely to improve overall public health. Also, confusions arise by applying the term deworming to a variety of very different helminth infections and to different treatment regimes, while local-level research in schools reveals that drug coverage usually falls below target levels. In most places where data exist, infection levels remain disappointingly high. Without indefinite free deworming, any declines in endemicity are likely to be reversed. Moreover, there are social problems arising from mass drug administration that have generally been ignored. Notably, there are serious ethical and practical issues arising from the widespread practice of giving tablets to children without actively consulting parents. There is no doubt that curative therapy for children infected with debilitating parasitic infections is appropriate, but overly positive evaluations of indiscriminate deworming are counter-productive.
Bank Skin in the Game and Loan Contract Design: Evidence from Covenant-Lite Loans
Authors: Billett Matthew T. , Elkamhi Redouane , Popov Latchezar , Pungaliya Raunaq S.
Published: July 2016

In a model of dual-agency problems where borrower–lender and bank–nonbank incentives may conflict, we predict a hockey stick relation between bank skin in the game and covenant tightness. As bank participation declines, covenant tightness increases until reaching a low threshold, at which point the relation sharply reverses and covenant protection is removed with a commensurate increase in spread. We find support for the hockey stick relation with bank’s stake in covenant-lite loans averaging 8% (0% median). We also find that covenant-lite loans are more likely when borrower moral hazard is less severe and when bank relationship rents are high.
The perceptions of non music staff and senior management of the impact of the implementation of the Musical Futures approach on the whole school
Authors: Hallam Susan , Creech Andrea , McQueen Hilary
Published: July 2016

This research aimed to provide an account of the impact of the Musical Futures approach on the wider school community in Musical Futures ‘Champion Schools’. Questionnaires were completed by 344 non-music teachers. Interviews were undertaken with members of senior management teams. The majority of staff indicated that Musical Futures had had a positive impact on student motivation, well-being, self-esteem and confidence and had encouraged students to work together. There was less agreement that it had improved student concentration, organisation and students’ attitudes towards learning and academic progression. The interviews provided deeper insights into the issues relating to implementation.
Airworthiness
Authors: Jameson D. M.
Published: July 2016

I would like to preface my remarks by gratefully acknowledging the inspiration I have received from my colleagues and others with whom the problems I shall talk about have been discussed, and by making it clear that, although my views are naturally coloured by the work on which I am engaged, they must not necessarily be taken as the official views of the Air Registration Board.

The supersonic aeroplane, due to its novelty, presents the three main types of airworthiness problem in a more pressing form. These are: knowledge of the environment; knowledge of what the aeroplane must be able to do in that environment (which includes a clear idea of acceptable risk); and obtaining, before passenger service, the necessary confidence that the intended safety level will be achieved. I can only touch on a few of the individual problems.
The First 25 Years of the Bristol Engine Department
Authors: Fedden Roy
Published: July 2016

Few things have given me greater satisfaction than the invitation to give the Seventh Barnwell Memorial Lecture, and tell the story of the early history of the Bristol Engine Department.

The Bristol Aeroplane Company which was founded by that great merchant venturer and pioneer of transport, Sir George White, has just passed its 50th Anniversary. I always look upon the 20 odd years spent with the Bristol Company as among some of the happiest and most stimulating in my engineering career.
The Royal Aeronautical Society The First Fifty Years
Authors: Laurence pritchard J.
Published: July 2016

The year 1868 was destined to be memorable and significant in the history of the Society. It was the year in which the first Aeronautical Exhibition in the world was held.

The Mechanics Magazine for 7th February 1868 said:

“ The objects for exhibition,” quoting from a circular issued by the Society, “ and for which prizes will be offered out of the funds now raising, are light engines and machinery, complete working apparatus, models (working and stationary), plans and drawings, articles of interest commemorating previous experiments, kites or other similar apparatus proposed to be used in cases of shipwreck, traction, or in the attainment of other useful ends; paintings of landscapes and cloud scenery observed from a balloon.”
The Training of Guided Missiles Engineers
Authors: Nayler J. L.
Published: July 2016

An All-Day Discussion on the Training of Guided Missiles Engineers was held by the Astronautics and Guided Flight Section of the Society in the Lecture Theatre on 16th March 1961. The Chair was taken by Mr. A. D. Baxter, M.Eng., F.R.Ae.S., M.I.Mech.E., F.Inst.P., Executive Director (Engineering), de Havilland Engine Co. Ltd.

Introductory papers were given by L. H. Bedford, C.B.E., M.A., B.Sc, A.F.R.AcS., Director of Engineering, Guided Weapons Division, English Electric Aviation Ltd.; Ian Dean, M.A., Education Officer, de Havilland Aircraft Co. Ltd.; F. G. Tarrant, Assistant Director, Guided Weapons (Engineering), Ministry of Aviation; Professor G. A. Whitfield, B.Sc, F.R.Ae.S., Professor and Head of Department of Aircraft Electrical Engineering, College of Aeronautics; Commander E. G. lege, Greenwich; Professor C. Holt Smith, C.B.E., M.Sc., M.I.E.E., Head of Department of Electrical and Instrument Technology, Royal Military College of Science, Shrivenham; and Wing Cdr. G. C. Wainwright, B.Sc, A.F.R.Ae.S., A.F.I.A.S., Chief Instructor, Weapon Systems Engineering Wing, R.A.F. Technical College, Henlow. The Discussion was opened by M. Armstrong, Chief Training Engineer, Bristol Aircraft Ltd.; Professor E. J. Richards, O.B.E., M.A., D.Sc, F.R.Ae.S., Professor of Aeronautical Engineering, University of Southampton; Colonel J. P. G. Lewis, War Office (Directorate of Equipment Production), and Colonel W. J. Mellors, M.B.E., School of Electronic Engineering, R.E.M.E. Twenty-three other speakers took part in the General Discussion.
Skylark
Authors: Hazell J. F.
Published: July 2016

Skylark is an upper atmosphere rocket designed to carry a payload of 150 lb. to a height of 100 miles. The project was the outcome of discussions between the Royal Society and the Ministry of Supply which started in 1953 and were completed in 1955 when Treasury approval was given for a joint Royal Society-Ministry of Supply programme of upper atmosphere research using a vehicle to be designed by the Royal Aircraft Establishment. The programme was the responsibility of the Gassiot Committee of the Royal Society, matters of detail being agreed at a working party and endorsed by the Gassiot Rocket Sub-committee.
Effect of Wall Divergence on Sonic Flows in Solid Wall Tunnels
Authors: Tirumalesa D. , Satyanarayana B.
Published: July 2016

The effect of wall divergence (in excess of the normal value given for compensating the Boundary Layer growth on the tunnel walls), on the simulation of Sonic flows in solid wall wind tunnels is presented in this note which is a condensed version of Ref. 1.

Recently Spreiter showed that flows with free stream Mach number one can be simulated reasonably well in choked solid tunnels. Berndt and Petersohn showed that the thickening of the boundary layer on the walls of solid wall tunnels reduced the interference considerably. Wall divergence θg in excess of the normal one of about one degree (used for Boundary Layer compensation) may lead to favourable conditions for the thickening of the Boundary Layer and this appeared to be an interesting way of reducing the interference.
On The Correlation and Presentation of Information on Turbulent Variable Property Heat Transfer in Tubes
Authors: Ward Smith A. J.
Published: July 2016

This note is concerned with the correlation and presentation of information on heat transfer under conditions of turbulent forced convection for the flow of gases in tubes. Discussion will be confined to the region where thermal entrance effects are absent and, furthermore, it will be assumed that the flow velocity is sufficiently low for compressibility effects to be neglected.

The subject matter will be discussed in general terms only and it is not intended to produce quantitative conclusions, which may, however, be found in reference 11.
Interference Effects in an Infinite Cascade of Wings of Finite Span
Authors: Lakshmi Narayana B.
Published: July 2016

Using Glauert's three-dimensional aerofoil theory, an expression for the induced velocity due to the trailing vortices of an infinite cascade of wings of finite span has been derived. The reduction in the average lift coefficient due to these induced velocities has been evaluated for some cases. It is shown that for a cascade of low space-chord ratio, the reduction in lift due to the interference from the trailing vortices is quite considerable.
R.101 and Other Airships—The Process of Development
Authors: Cave-Browne-Cave T. R.
Published: July 2016

In addressing the Historical Group it is desirable to let technical detail fall into the background so that the more general consideration of personal problems, policy and organisation can be clearly examined.

Technical detail changes so much more with time than do the human and administrative considerations, that the greatest value for history comes perhaps from the study of the latter.
The Relative Roles of Man and Instruments in Space
Authors: Francis R. H. , Hilton W. F.
Published: July 2016

This Discussion, held by the Astronautics and Guided Flight Section on 11th December 1962 in the Lecture Theatre, 4 Hamilton Place, London W.1, was introduced by R. H. Francis, B.Sc, M.Sc, F.R.Ae.S., F.B.I.S., and W. F. Hilton, D.Sc, Ph.D., A.R.C.S., D.I.C., F.R.Ae.S. The following report was prepared by J. L. Nayler, M.A., F.R.Ae.S., F.A.I.A.A.

This interesting discussion ranged over the whole known field from that of near space with meteorological, communications, navigation and astronomical satellites, from prestige flights and satellites with military applications to interplanetary space with all the added difficulties arising from radiation and other engineering problems; landings and bases were mentioned as regards the planets. The desirability of this country having its own space problem, in addition to co-operation with other countries in Europe, was touched upon. The discussion was opened by Mr. R. H. Francis and Dr. W. F. Hilton, the former concentrating mainly on the instrumental rôles and the latter on the irreplaceability of man in certain aspects of space development.
Legal Liabilities Arising out of Aircraft Design and Manufacture
Authors: Beaumont K. M. , White C. B.
Published: July 2016

The second lecture to be given before the Air Law Group of the Society "Legal Liabilities Arising out of Aircraft Design and Manufacture" was given on 19th December in the Lecture Theatre, 4 Hamilton Place, London, W.l. The Lecture was in two parts, Major K. M. Beaumont, C.B.E., D.S.O., M.A., A.F.R.Ae.S., F.R.S.A., F.R.P.S.L., speaking from the legal point of view and Mr. C. B. White, M.A., Hawker Siddeley Aviation Ltd., sneaking from the manufacturer's point of view. The Chair was taken by Mr. Walter Tye, O.B.E., B.Sc., F.R.Ae.S., Chief Technical Officer, Air Registration Board. The report of the Discussion was prepared by Mr. B. J. Davenport, B.A.
The Elastic Critical Loads of Coupled Struts
Authors: Waters H.
Published: July 2016

In previous notes approximate values of the elastic critical loads of continuous and composite struts were obtained. In the case of continuous struts a semi-graphical technique was employed, while for composite struts values were derived from approximate solutions of the transcendental equations governing the behaviour of the struts. In the present note, the approximate elastic critical loads of coupled struts are investigated by a third method, using approximate expressions for the stiffness and carry-over factors entering into the equations expressing the critical conditions of the struts.
VTOL Aircraft: A Survey of Some of Their Characteristics with Special Reference to Civil Use
Authors: Cheeseman I. C.
Published: July 2016

A review of the various means of producing vertical take-off is made and the salient advantages and disadvantages of each type discussed. The place of the vertical take-off aircraft in the air transport picture is considered and the optimum type of aircraft for each role suggested.
Blue Streak Static Firings
Authors: Hume C. R.
Published: July 2016

Blue Streak is to be the first stage booster of a three stage satellite and space probe launcher being developed in Europe. The main contractor for the Blue Streak rocket vehicle is Hawker Siddeley Dynamics Ltd. with the propulsion system the responsibility of Rolls-Royce Ltd. The work reported in this paper was carried out under Ministry of Aviation contract and forms part of the United Kingdom participation in the initial programme of the European Launcher Development Organisation (E.L.D.O.).

The static or “tethered” firing of liquid-propelled rocket vehicles is an essential process in the establishment of operational reliability before attempting launchings.
Modern Methods of Investigating Flutter and Vibration
Authors: Hitch H. P. Y.
Published: July 2016

The past several years have seen a steady advance in the techniques employed in flutter and vibration analysis. At the same time aircraft performance has been improved on every front and margins have had to be reduced: it is only by making full use of these modern methods that the accepted margins of safety have been preserved.

The paper reviews the processes which are currently used in the prediction and prevention of aircraft flutter in contrast to those of a few years back. The more recent types of flutter which have had to be considered are discussed briefly in relation to the methods which have been developed to deal with them. Ground and Flight testing methods are reviewed together with the use to which the results are put.

Finally there is a discussion of the increasing need to predict sub-critical response. The methods employed are discussed in relation to the more important problems.
A Driving Mechanism for High Frequency Combustion Instability in Liquid Fuel Rocket Engines
Authors: McCormack P. D.
Published: July 2016

The problem of combustion pressure oscillation in liquid-fuel rocket motor operation has long been the subject of theoretical and experimental investigations.

The low frequency (less than 200 cps) type of oscillation, known as “chugging”, has been thoroughly analysed and the problem solved (see Crocco, 5th Combustion Symposium, p. 164).

This Note is concerned with the more complex (and more destructive) high frequency oscillations, covering a range from about 1000 to 6000 cps. Such oscillations can resonate with the acoustical modes of the combustion chamber. Longitudinal, tangential and radial oscillating modes have been observed.
Elastic Stability of Cylindrical Shells under Axial and Lateral Loads
Authors: Lakshmikantham C. , Gerard George
Published: July 2016

In the stability analysis of cylinders under external loading, the axial compression and lateral pressure cases are relatively well established: see, for example, ref. 1. However, from a design point of view, a biaxial system of forces due to a combination of axial compression and external pressure is often encountered in launch vehicle structures. While many other combined loading cases have appeared in the literature, the case under present consideration has not; therefore, this note is devoted to a general treatment of this problem. It is to be noted that Radhakrishnan presented some specific results for this loading combination for elastic and plastic buckling.

Using the Donnell equation for small deformations, the present report considers the effect of various compressive loading combinations on the stability problem of an un-stiffened circular cylinder.
A Finite-Difference Approximation to a Non-Self-Adjoint Eigensystem
Authors: Saravanos B.
Published: July 2016

The solution of some non-self-adjoint eigensystems describing the elastic instability of structural elements requires essentially the determination of the minimum value of a parameter associated with the eigenvalues. Usually, a substantial programme of computation is implicit in this type of system.

During a preliminary consideration of possible methods of practical computation for a certain problem of this kind, which is currently being investigated by the author, the question arose concerning the suitability of a finite-difference approximation for the purpose. The object of such an approximation was to provide a relatively rapid, if crude, means for a first estimate of the solution by desk-calculation methods.
Instrument Displays for Blind Flying
Authors: Holden K. J.
Published: July 2016

In the early part of this century aircraft were flown only when the pilot could control them by reference to outside sources—the ground, the sky and the horizon. Soon, however, instruments were developed which enabled him to fly in cloud or darkness. The Second World War with its blackout enforced this need for total blind flying and, as a consequence instruments and techniques were perfected, ending with what was known as the standard blind flying panel. This has remained substantially unchanged in the majority of aircraft up to the present day. This paper reviews the presentation and the principles which led to its development and then discusses some recent developments in this interesting field. First it is necessary to look at the problem in more detail.
The Measurement of the Drag of Bluff Bodies by the Wake Traverse Method
Authors: Maull D. J. , Bearman P. W.
Published: July 2016

The drag of an aerofoil is often conveniently measured with reasonable accuracy by traversing pitot and static tubes across the wake of the aerofoil and calculating the drag from either the analysis of Betz or that of Jones.
Microbiological Attack in Aircraft Fuel Systems
Authors: Lansdown A. R.
Published: July 2016

— A great deal of publicity has been given in recent years to the problems caused by microbiological attack on aviation fuels, although there had been considerable experience of the subject before the first serious problems arose in aviation. Intensive studies of the nature of the attack have shown that although limited use of biocides has been successful, the best control is by the elimination of stagnant water from the fuel supply system and the aircraft fuel system.
Agricultural Pilots’ Training
Authors: Maan W. J.
Published: July 2016

It must be obvious to anyone who has anything to do with agricultural aviation, that the training of agricultural pilots has, lately, received more attention than ever before. There are several good reasons for this and before speaking of the training itself, as it is carried out in the different countries, I feel that it might serve a useful purpose to go into these reasons more deeply.

The first part of the subject, that is, the reason why we are forced to pay more attention to the training of agricultural pilots than we have in the past, I have often mentioned both by word of mouth and in writing. This will not prevent me, however, from doing so again. This whole question is, in my opinion, of prime importance.
Training
Authors: Eadon Alan
Published: July 2016

Having been asked to recount a brief history of the origin and conception of the Aeronautical Technical School Movement, I wish to pay the highest tribute to the philosophy, example, logical methods and encouragement of those men from whom I had the good fortune to receive my own training and under whom I was privileged to serve. Their sterling qualities were co-ordinated and embodied in the establishment of the first Civil Aeronautical Technical School and have led to the achievements of countless of its pupils.

The basic principles of the School have remained unaltered but they have been adapted and amplified, with success, to meet the requirements of subject, numbers, nationality, language, character, creed and environment, for a variety of projects for Governments and Industry, involving the training of individuals and small classes up to many thousands of trainees—maximum results in the minimum of time being the objective.
The Good Old Days
Authors: Tinson Clifford W.
Published: July 2016

The title chosen identifies the period when flying was an adventure; when the design and construction of aeroplanes and attempts to become airborne on them, whether successful or not, created the pleasure and satisfaction that is felt by the “do it yourself” enthusiast who, with little previous experience to guide him, ventures more or less into the unknown; when every failure and disappointment is a spur, a stimulus and a positive urge to try again and do a little better next time. This period began seriously not much more than sixty years ago.

In this age when people are being whisked to the ends of the earth at speeds approaching Mach one and when tremendous efforts are going forward to propel them there two or three times faster than that, it is almost incredible that the progress which we have seen take place could have been possible in such a comparatively brief period.
A Young Man's View of the Aerospace Profession
Authors: Fincher H. M.
Published: July 2016

When one talks of the difficulties of the aerospace industry in this country, it is all too easy to point a finger westwards to the United States. It then seems right to talk of long production runs and large home markets. One can then turn to our own industry and to its output since the last War, and perhaps forgive.

But should we?

In this short paper, a young author intends to examine professional education and manpower in aeronautics, because herein must be the reason for any future success or failure of the products of the industry, and the pointer to the future level of expertise in the art.
Some Formulae for Deflection and Volumetric Displacement of a Flat Circular Plate
Authors: Skorecki J.
Published: July 2016

Exact expressions for deflection, swept volume and the ratio of the balancing force to the total thrust due to pressure are given for the case of a flat circular plate subjected to a uniform normal pressure and held fixed both in displacement and slope on the periphery and at an inner radius.
Aircraft with Stressed Skin Metal Construction
Authors: Short H. O.
Published: July 2016

I exhibited the “Silver Streak” before a patent was granted to me because my Patent Agent, the late Mr. Griffith Brewer, had asked me to allow him to make a search, and this took a considerable time. What he found as being the “state of the art” is described in my first patent, 185,992, in clauses 70 to 85 on the first page. (Application date, 10 November 1921; Complete Left 15 February 1922; Complete Accepted 21 September 1922). None of those projects described as being the “state of the art” were ever carried into practice successfully, and a study of statements in 70 to 85 will show that the Inventors had failed to realise that such structures as they visualised could not safely be made, as indeed they were never made, and carried into practice in an actual aeroplane or flying-boat.
The Warsaw Convention and the Washington Compromise
Authors: Lowenfeld Andreas F.
Published: July 2016

Half a year has passed since the major airlines of the world, in a burst of energy, rallied round to “save” the Warsaw Convention. The Convention had as its principal effect a limitation of $8300 (not quite £3000) on liability of air carriers to international passengers for death or injury, and the United States had given formal notice that it could no longer accept this. The effort to update the Warsaw Convention of 1929 had, essentially, failed so far as the United States was concerned, in that the revision proposed at the Hague Conference in 1955 was only double, the Warsaw limit—$16 600 or £6000— still far below an acceptable ceiling on recoveries for accidental death caused by common carriers. The United States Senate had not ratified the Hague Protocol, it clearly was not going to, and all attempts by the United States Executive Branch to supplement the Warsaw/Hague limits—such as by compulsory trip insurance or voluntary waiver of limits by the carrier—had come to naught.
The Aerial Photography of Potato Blight Epidemics
Authors: Brenchley G. H.
Published: July 2016

In spite of more active fungicides and improved methods of application, including the use of aircraft, the control of potato blight is not very much better than it was thirty years ago. The basic weakness appears to be the impossibility of achieving and maintaining anything like a complete fungicide cover on the foliage of a growing crop of potatoes. In every season in which the weather favours the parasite a time comes when the number of blight spores is so great that many of the gaps in the fungicide defence cover are bound to be penetrated. Once a number of infections have thus been established in a crop, the progress of the disease is only a matter of time and weather, for each of the new infections normally becomes an ineradicable centre for further spread. If this diagnosis is essentially correct, the chances of major improvements in blight control with our present methods are small. It is therefore desirable to examine the history of blight epidemics in detail, to see if there is any possibility of delaying the build-up of the spore inoculum. This would give the protective fungicides a better chance of holding off the attack until the crop had produced its full potential yield.
The TRIAX 6 Element for Axisymmetric Analysis by the Matrix Displacement Method
Authors: Argyris J. H.
Published: July 2016

The investigation of axisymmetric states of stress by the matrix displacement method may, in principle, be carried out as an ordinary exercise of three-dimensional analysis, using TETRA 4, TETRA 10 or other suitable elements. However, this approach is clearly not the most efficient by not taking advantage ab initio of the inherent simplifications arising in an axisymmetric state; this leads to an unnecessary inflation of the number of unknowns and complexity of the mesh. A number of techniques to deal with this limiting condition of a three-dimensional state have been developed at the ISD. The theory for one specific element, TRIAX 6 which evolves most naturally from the tapered TRIM 6 element analysed in the preceding note 8 is presented.
Identifying Fallers among Home Care Clients with Dementia and Parkinson’s Disease
Authors: Bansal Symron , Hirdes John P. , Maxwell Colleen J. , Papaioannou Alexandra , Giangregorio Lora M.
Published: July 2016

Il y a eu peu d’études qui se concentrent sur les chutes chez les clients qui reçoivent des soins à domicile (SD) avec des conditions neurologiques. Cette étude a identifié les facteurs qui accroissent le risque de chutes chez les clients SD sans histoire récente de telles chutes, et a exploré si les profils de risque variaient parmi les personnes atteintes de démence ou le parkinsonisme, par rapport à celles sans conditions neurologiques sélectionnés. Une étude de cohorte rétrospective a été utilisée, et l’analyse des données provenant de clients SD communautaires de l’Ontario a été menée sur un échantillon de clients ambulatoires atteints de démence, de parkinsonisme, ou d’aucune des conditions neurologiques sélectionnées. Les données ont été obtenues à partir de l’instrument d’évaluation des résidents en soins à domicile (IERSD-SD). Dans l’analyse multivariée, le résultat utilisé était de savoir si les clients ont tombé au cours du suivi. Une démarche instable était un fort prédicteur des chutes dans les trois groupes. Le parkinsonisme co-morbide a prédit plus fortement les chutes dans le groupe de démence. Les clients qui ont montré la limite intacte à la déficience cognitive légère étaient plus susceptibles de se sont trouvés dans les groupes de parkinsonisme et de comparaison. Les chances de tomber étaient plus élevées pour les clients avec la limite intacte à la déficience cognitive légère qui également faisaient partie des groupes de la maladie de Parkinson et de comparaison.
Predicting substance use in emerging adulthood: A genetically informed study of developmental transactions between impulsivity and family conflict
Authors: Elam Kit K. , Wang Frances L. , Bountress Kaitlin , Chassin Laurie , Pandika Danielle , Lemery-Chalfant Kathryn
Published: July 2016

Deviance proneness models propose a multilevel interplay in which transactions among genetic, individual, and family risk factors place children at increased risk for substance use. We examined bidirectional transactions between impulsivity and family conflict from middle childhood to adolescence and their contributions to substance use in adolescence and emerging adulthood (n= 380). Moreover, we examined children's, mothers’, and fathers’ polygenic risk scores for behavioral undercontrol, and mothers’ and fathers’ interparental conflict and substance disorder diagnoses as predictors of these transactions. The results support a developmental cascade model in which children's polygenic risk scores predicted greater impulsivity in middle childhood. Impulsivity in middle childhood predicted greater family conflict in late childhood, which in turn predicted greater impulsivity in late adolescence. Adolescent impulsivity subsequently predicted greater substance use in emerging adulthood. Results are discussed with respect to evocative genotype–environment correlations within developmental cascades and applications to prevention efforts.
Principles of Management Lessons 9: Group Dynamics in Disasters
Authors: Cuny Fred C.
Published: July 2016

A disaster is the most acute example of an unusual situation and the disaster manager must operate in an environment in which pressures and events forge unusual combinations of people. The working environment is influenced by: 1) pressure; 2) inexperience of the workers; 3) perceptions; 4) working conditions; and 5) reactions of the worker to the disaster. Disaster workers are motivated by: 1) humanitarian concern; 2) happenstance; 3) excitement; 4) grief; 5) guilt; or/and 6) opportunism. Group dynamics include the formation and function of the “disaster community” and inter-organizational relationships. The disaster community evolves around the spontaneous appearance of natural leaders, but eventually, these leaders and the disaster community are replaced by more formal organizations that are part of the relief operations and that rarely include the disaster community. In the longer term, as reconstruction begins, the organizational structure becomes more professional. Each of these phases provokes different group dynamics that must be considered by the disaster managers. Such implications are outlined in the discussion.
A Virtual Reality Patient Simulation System for Teaching Emergency Response Skills to U.S. Navy Medical Providers
Authors: Freeman Karen M. , Thompson Scott F. , Allely Eric B. , Sobel Annette L. , Stansfield Sharon A. , Pugh William M.
Published: July 2016

Rapid and effective medical intervention in response to civil and military-related disasters is crucial for saving lives and limiting long-term disability. Inexperienced providers may suffer in performance when faced with limited supplies and the demands of stabilizing casualties not generally encountered in the comparatively resource-rich hospital setting. Head trauma and multiple injury cases are particularly complex to diagnose and treat, requiring the integration and processing of complex multimodal data. In this project, collaborators adapted and merged existing technologies to produce a flexible, modular patient simulation system with both three-dimensional virtual reality and two-dimensional flat screen user interfaces for teaching cognitive assessment and treatment skills. This experiential, problem-based training approach engages the user in a stress-filled, high fidelity world, providing multiple learning opportunities within a compressed period of time and without risk. The system simulates both the dynamic state of the patient and the results of user intervention, enabling trainees to watch the virtual patient deteriorate or stabilize as a result of their decision-making speed and accuracy. Systems can be deployed to the field enabling trainees to practice repeatedly until their skills are mastered and to maintain those skills once acquired. This paper describes the technologies and the process used to develop the trainers, the clinical algorithms, and the incorporation of teaching points. We also characterize aspects of the actual simulation exercise through the lens of the trainee.
A Comparison of Rural and Urban Emergency Medical System (EMS) Personnel: A Texas Study
Authors: Chng Chwee Lye , Collins John , Eaddy Starr
Published: July 2016

Introduction:

In treating accident victims, actions by the Emergency Medical Personnel (EMP) at the scene may be the difference between life or death, full recovery or permanent disability. Development of selected profiles based on locale of services, tenure, and paramedic certification will provide valuable insight into the diversity within the Emergency Medical Services (EMS) profession. Not only will these profiles enable administrators to improve their recruitment, training, and retention of the emergency medical workforce, it potentially could enhance the quality of health care in the community.

Population:

Emergency medical personnel attending a statewide conference in Texas in late 1996 (n = 425).

Hypotheses:

1) There is no difference between the profiles of urban and rural emergency medical personnel; 2) There is no difference between the profiles of urban EMP with <9 years of experience and those with ≥9 years of experience; 3) There is no difference between the profiles of rural EMP with <9 years of experience and those with ≥9 years of experience. 4) There is no difference between the profiles of urban EMP with paramedic certification and those without certification; and 5) There is no difference between the profiles of rural EMP with paramedic certification and those without certification.

Methods:

EMP attending the conference completed 425 survey instruments measuring five demographic features, five work-related features, and two psychological features. Survey instruments were included in each registrant's conference package. Completed surveys were deposited anonymously in labeled receptacles throughout the statewide conference site. Data collection ceased at the end of the conference. Discriminant analysis identified distinct profiles for the urban and rural EMP.

Results:

The urban EMP, more than rural subjects, was younger (mean = 36 years), more likely to be compensated 100% for their services, had a higher level of education (mean = 13.8 years), and reported a lower level of burnout. Urban EMP with <9 years of experience tended to be younger, male, married, and reported less burnout. Urban paramedics were more likely to be compensated 100% for their services, and had achieved a higher level of education. The rural EMP with <9 years of experience were less likely to be paramedic, reported lower burnout scores, and was younger. The rural EMP without paramedic certification was more likely to be a volunteer, and have had fewer years of service.

Conclusions:

In Texas, locale of service (urban or rural), length of tenure as an EMP (>9 years), and paramedic certification appear to be significant factors that define the EMP population in Texas.
Saliva Alcohol Reagent Strips in Altered Response Protocols
Authors: Harpe Keith G. , Yealy Donald M. , Heller Michael B. , Kaplan Richard M. , Fochtman Fred W.
Published: July 2016

The prehospital care provider has been limited in his or her initial assessment of patients due to having available only a limited number of simple diagnostic tests. There has not been an accurate field test available to rule out significant ethanol intoxication. We designed a prospective trial for the prehospital setting to test the utility of a rapid, semi-quantitative, saliva alcohol reagent strip for patients with an altered level of consciousness. We found that these strips were useful in ruling out significant ethanol intoxication as a cause of an altered level of consciousness with a sensitivity of 85.7% and a specificity of 94.4%, but were not useful in accurately predicting the blood alcohol level. We conclude that these reagent strips are useful in the prehospital setting to provide information about patients with an altered level of consciousness.
The Need for a Prehospital DNR System
Authors: Crimmins T. J.
Published: July 2016

Initiation of cardiopulmonary resuscitation when the death is the result of an end-stage, irreversible, and imminently terminal illness against the patient's prior request is immoral and indefensible. Medical providers should withhold treatments that are futile, and individuals have the right to refuse this invasive therapy.

The use of Do-Not-Resuscitate (DNR) orders has become a standard of medical care in health care institutions and should be incorporated into the prehospital medical care system. The American College of Emergency Physicians (ACEP) supports their use, and the National Association of Emergency Medical Services Physicians (NAEMSP) has developed a consensus paper endorsing the use of prehospital DNR orders. The Joint Commision on the Accreditation of Hospitals (JCAH) recommends the use of DNR orders and the American Heart Association (AHA), in Standards and Guidelines for Advanced Cardiac Life Support, recognizes their validity. It is time for EMS systems to develop and implement policies and procedures, with adequate safeguards, to allow the withholding of CPR in specific circumstances. The claim that DNR orders cannot be honored in the prehospital setting is a self-fulfilling prophecy. If an emergency medical services (EMS) system lacks strong medical leadership or believes that a prehospital DNR system cannot work–a communitywide DNR program never will come into existence. Dying patients will continue to suffer the indignity and burden of unnecessary and futile treatments that serve no benefit to the patient and only serve to alienate and anger the family members.
Evaluation of Preparedness and Response to Hurricanes Georges and Mitch: Conclusions and Recommendations
Authors:   16-19 February 1999, Santo Domingo, Dominican Republic Pan American Health Organization/World Health Organization
Published: July 2016

Mr. Chairman, Ladies and Gentlemen, first let me thank you for coming to this meeting that has been organized by us in close collaboration with UYDP, OCHA, UNIGEF and IDNOR with generous support from the Canadian, UK, and USA development agencies. It always is a pleasure to recognize our partners.

We have with us here today representatives of a large number of agencies, institutions, NGOs, and private individuals. This cross section of interests is a manifestation of a growing and irreversible trend. The important issues of our time cannot be dealt with solely by nations, agencies, or individuals, even the most powerful ones. The phenomenon of globalization no longer is restricted to economic or financial matters: it is now evoking the wide participation of ranges and numbers of actors that would have been unthinkable a few decades ago. In almost all aspects of our work, we are looking to find the partners and interests that can bring value to the management of the issue or the search for solutions, if definitive solutions ever can be found to the really important human challenges.
Current Extent of Disasters in Africa
Authors: Nur Idris M.
Published: July 2016

The people oFf Africa are exposed to a wide range of disasters that seriously have aggravated the Continent's economic situation. Economic losses and human sufferings from drought, desertification, locust infestation, infectious diseases, epidemics, and armed conflicts are the dominant disasters that the people in the African countries face, and they have rendered the population utterly vulnerable. Disasters have aggravated Africa's economic situation. The cumulative effect of disasters include loss of property, injury, death, mounting food import bills, health hazards, environmental degradation, backward economic development, displaced people, refugees, and nutritional deficiency.

Today, 175 million Africans out of a total population of 744 million people (23.5%) are suffering from chronic hunger; this is an increase of 50% from 25years ago. In many African countries, up to half of the population suffers from absolute poverty. It is projected that Africa will be the only Continent to continue with the current level of poverty for another decade.