bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of gefitinib (Iressa) on mammary cancers: preventive studies with varied dosages, combinations with vorozole or targretin, and biomarker changes
Authors: Lubet Ronald A. , Szabo Eva , Christov Konstantin , Bode Ann M. , Ericson Marna E. , Steele Vernon E. , Juliana M. Margaret , Grubbs Clinton J. 
Published: March 2008

Abstract
The ability of the epidermal growth factor receptor inhibitor gefitinib (Iressa) to prevent/treat methylnitrosourea (MNU)-induced mammary cancers and to modulate biomarkers in female Sprague-Dawley rats was examined. Rats were given a single dose of MNU (75 mg/kg body weight) at 50 days of age. In the prevention studies, continual treatment with Iressa at 10, 3, or 1 mg/kg body weight per day beginning 5 days after MNU reduced tumor multiplicity by 93%, 43%, and 20%, respectively. Treatment of rats bearing small palpable cancers with Iressa (10 mg/kg body weight per day) resulted in the complete regression of 70% of the tumors. Short-term treatment of tumor-bearing rats with Iressa caused decreases in cell proliferation and phosphorylated epidermal growth factor receptor and increases in apoptosis. To examine treatment regimens that might decrease the skin toxicity associated with Iressa, both intermittent treatments and combinations of lower doses of Iressa with other effective agents were evaluated. Treatment with Iressa (10 mg/kg body weight per day) continually or intermittently (either “3 weeks on/3 weeks off” or “4 days on/3 days off”) reduced cancer multiplicity by 91%, 24%, and 68%, respectively. However, all regimens reduced tumor weights &gt;85%. Finally, combining suboptimal doses of Iressa with suboptimal doses of vorozole (an aromatase inhibitor) or targretin (a retinoid X receptor agonist) yielded greater chemopreventive efficacy than any of these agents given alone. [Mol Cancer Ther 2008;7(4):972–9]
What Has Happened to the Laws? The Treatment of Legal Material in 4QReworked Pentateuch
Authors: Bernstein Moshe 
Published: March 2008

AbstractThe biblical or non-biblical nature of the manuscripts currently identified as 4QReworked Pentateuch (4Q158; 4Q364–67) has been the subject of much scholarly discussion. This paper addresses a facet of those texts which has unfortunately been ignored in most of those discussions, namely their treatment of the legal material in the Pentateuch. An examination of the surviving legal portions of 4QReworked Pentateuch, manuscript by manuscript, indicates that much greater freedom is shown in handling the laws than in any known pentateuchal textual tradition. We find that laws are omitted from their original locations in the Pentateuch, and, almost without exception, do not reappear in a new location. There also appears to be almost no exegetical reworking of the laws. We conclude that we should not presume that the 4QRP texts included the entire Pentateuch, and that their omission of legal material should probably lead us to characterize some, if not all, of them as non-biblical.
Decoration, Destruction and Debauchery: Reflections on 1 Enoch 8 in Light of 4QEnb
Authors: Coblentz Bautch Kelley 
Published: March 2008

AbstractThis article takes up the distinctive text of Synkellos for 1 En. 8:1 and asks whether it offers the preferred reading or at least may be defended as an early variant rather than as an interpolation of the Byzantine chronographer. To that end, the article examines the Greek translation featured in Synkellos's Chronography and compares the text to other manuscript traditions, especially to the Aramaic fragments of Enoch found in Cave 4 of Qumran. Close examination leaves the author reluctant to dismiss the reading of Synkellos. Further, the author argues that Genesis 4 and 6 might have provided a warrant for this sort of interpretative tradition inasmuch as culture bringers (i.e. the Cainites) precede the account of the angels' descent and mating with women as one finds in Synkellos's version of 1 En. 8:1.
The Community Hymns Classification: A Proposal for Further Differentiation
Authors: Kim Harkins Angela 
Published: March 2008

AbstractThe hodayot scroll from Cave 1 is often cited as one of the classic examples of sectarian literature found at Qumran, yet this conceptualization ignores the great variety of language and style found throughout these compositions. Perhaps a refined understanding of the different literary types within the hodayot scroll can help lead scholars to a better understanding of the relationship between it and other writings from Qumran. This paper proposes that the specific group of hodayot known as the Community Hymns may be further differentiated into two types: those that show strong alignment with the yahad and those that do not show strong alignment.
Simulation in the Service of Society
Authors: McLeod John , McLeod Suzette 
Published: March 2008

In my 1982 book, Computer Modeling and Simulation: Principles of Good Practice, I emphasized the importance of definitions of terms to be used in the book by placing them right after the introduction, in the hope that by so doing readers would have a clearer understanding of what the rest of the book was about. I was pleased to find that one of the terms defined in the book, "Simuland—The real or hypothesized system which is, or is to be, simulated," has been given legitimacy by appearing in The New Shorter Oxford English Dictionary as, "That which is simulated by a mathematical or computer model" shown as having been introduced in the mid-twentieth century. Now, some 18 years later, a group of "Glossarians" led by Scott Harmon of the Zetetex Company is taking ad vantage of progress in the art and science of M&S to pro duce a greatly enhanced glossary of terms and definitions. The following is an article by Scott on the subject.—JM
Examples of Analog Computer Applications in Nuclear Processes
Authors: Cameron W.D. , Taylor G.R. 
Published: March 2008

The purpose of this report is to outline and explain the various methods used in simulating atomic re actors and processes, particularly the types used at the Hanford plant. This report describes the newer as well as the standard techniques used in reactor simulation. Applications are described by examples. The techniques used in a complete atomic reactor plant simulator are described. Chemical processing simulations are discussed using specific examples.
Simulation of a Biological System On an Analog Computer
Authors: DeLand E.C. 
Published: March 2008

The purpose of this paper is to discuss a method for the construction of a mathematical model of a large biological system. This method, based on Gibbs' free energy hypothesis, uses the format of mathematical programming, while the actual computation is ac complished by the method of steepest descent. The biological system chosen to exemplify the mathe matical method was the respiratory function of the blood in the human lung. This method is based on the postulate that chemical mixtures tend toward a reaction equilibrium which minimizes the potential, or free energy, of the system. We may thus write down the classical Gibbs free energy function for each chemical species, and require that total free energy relative to some standard state be minimized under the conditions of the experiment. The solution of the equilibrium problem consists of a set of mole numbers which minimizes the free energy function, subject to equations for conservation of mass and nonnegativity. The analog computer solution of the respiration model was undertaken not only to give fast, sensitive tests of the mathematical model and its assumptions, but also to obtain a simulation of the time depend ent system. Examples of the mechanization of the equations are presented in this paper, and also results are computed for the static equilibrium of a canoni cal model.
A Method of Generating Functions of Several Variables Using Analog Diode Logic
Authors: Wilkinson R.H. 
Published: March 2008

A diode-resistor network technique for simulating functions of any number of variables is described. The function is approximated by a polyhedron, or its N-dimensional equivalent, and this polyhedral model is generated directly by the circuit. The circuit is formed of two cascaded sections: the first, using resistive networks, generates voltages representing each of the faces of the polyhedron; the second section, using analog diode logic, selects the appro priate voltage as the output. The analog diode logic uses basic circuits similar to those used in digital logic. It is shown that the analog logic can be described by a distributive lattice, closely related to Boolean algebra. Methods of logic synthesis are developed. Circuit design is discussed, and it is shown how the effect on the logic section of the finite source impedance of the resistive net works which feed it can be turned to practical ad vantage. The specific example of the multiplication of two variables is studied in some detail, providing a basis of comparison with the known techniques such as the quarter-square and log-antilog methods. Finally, test results on a simple three-variable function gen erator are given. The method is not incremental in nature, and differs from current techniques in this regard. Thus the setting up of a function on a generator is simpli fied, owing to the noninteraction between segments. Also, the area of the input space to be covered is adjustable to correspond with the input domain of the function.
A Simulation of a Generalized Thermal Radiating Fin
Authors: Janicke M.T. , Just L.C. 
Published: March 2008

The purpose of this paper is to provide a method for designing radiator fins with maximum heat removal capability per pound of construction material. This problem becomes important when radiators are designed for space applications, since all of the heat from the thermodynamic cycle must be removed by means of radiation. Moreover, space transportation vehicles are seriously limited as to payload, so that weight must be saved in all parts of a power plant. An increase in the output of a space power plant does not change the reactor, turbine, and generator as much as the radiator, with the result that, for megawatt electrical systems, the radiator is the dominant weight contributing component. A radiator could be built of coolant tubes alone, but this increases certain hazards. Meteor punctures can occur, so that the amount of area devoted to coolant tubes should be reduced as much as pos sible. Fins attached between the tubes can perform this function by extending the heat radiating surface. The extra weight of the fins is partly compensated for by a reduction in tubes and coolant. Extra savings can occur if the weight of the fin is minimized; optimum thickness, length, and cross section must be found. This paper studies the relationship between fin cross- section and radiating power.
A Wide-Band Computing Amplifier and A High-Speed Analogue Multiplier
Authors: Barber Derek L.A. 
Published: March 2008

The design of an operational amplifier is discussed and theoretical values of stage gains for maximum bandwidth are deduced. A practical circuit is de scribed in which these theoretically desirable stage gains are achieved. The result is an amplifier with a bandwidth about two orders greater than is commonly attained, which, furthermore, is the best performance that may reasonably be realized with the valves that are employed. The amplifier, together with a high-speed multi plier, forms the basis of the Fast Analogue Com puting Equipment (FACE) developed at the National Physical Laboratory.
Dynamic Programming and Hybrid Computation
Authors: Vichnevetsky R. , Waha J.P. 
Published: March 2008

Dynamic programming finds its use in operations research, chem ical engineering, control systems, and other fields of applied mathematics; and is primarily concerned with the optimisation of multistage decision processes. Dynamic programming will split up the problem into a succession of N one-dimensional optimisation problems. The optimising action takes place at each discrete stage of the process. The technique is based on the so-called principle, of opti mality, as expressed by Bellmann. The paper describes the various techniques involved. A hybrid analogue/digital computer will serve as an ideal tool, having the ability to integrate differential systems of equations, and also to perform the logical operations required in connec tion with the optimisation of the return function.
Experiments Using Pseudo-Random Noise
Authors: Hampton Robert L. 
Published: March 2008

This paper describes the results of experiments per formed with pseudo-random noise sequences. It is shown that Gaussian noise can be easily produced from such sequences. It is also demonstrated that the sequences themselves have a binomial proba bility distribution. The correlation technique investigated, using pseudo-random noise, makes possible a continuous recording of a system's impulse response without the use of any sophisticated hardware. The impulse re sponse obtained from the cross-correlation experi ment can be approached from either the positive or negative direction, i.e., τ can be made not only a time delay, but also a time advance. This enables one to observe the trailing end of a waveform before viewing its leading end. It also permits a quick ex perimental verification of the correlation property that Rxy(τ) = Ry,r(—τ). Examples for a first- and sec ond-order system are given.
Hybrid computing: a user's view
Authors: Clancy John J. , Fineberg Mark S. 
Published: March 2008

The analog computer section of the McDonnell Automation Center has been involved in hybrid com puting for some time now, leading us to think we can contribute to the dialogue now proceeding on the subject. In this article we first detail the only rational criteria for selecting a computing method, namely cost and capability, and then present the classes of problems that are prime candidates for hybrid solu tion. A brief description of our present facility is included, along with our views on selecting hybrid programmers. Looking ahead, we have outlined requirements for a future hybrid system, placing a good deal of em phasis on software needs, especially a simple, parallel language based on MIDAS, DYSAC, etc. An exam ination of hardware costs and the characteristics of the new breed of digital computers suggests that, although hybrid computation can be done more efficiently with the new generation, there is a pos sibility that neither hybrid nor analog computation in their present forms can survive the onslaught of low-cost digital computing. The outlook is not as bleak as first appears, since we believe analog con cepts can be retained in future systems, but only if SIMULATION readers and other interested parties are willing to make an issue of it.
Digitalization of continuous control systems
Authors: Breuer M.A. 
Published: March 2008

This paper deals with the development of methods for analysis, and derivation of computer programs, for digitalizing continuous control systems. More spe cifically, given a continuous control system, we wish to determine an "equivalent" computer program to take the place of some analog shaping network in the system. An equivalent program is one for which the response of the digital system approximates the response of the continuous system in the time do main. Time and frequency comparisons between the responses of continuous and digitalized systems to step inputs are given. Equivalent computer programs for various standard shaping networks are derived. Revised programs are determined, where use is made of prediction and extrapolation techniques to com pensate for digital computation delay time. Finally, the feedback network in a missile control system containing an unstable aerodynamic airframe is digitalized, and the simulated system is run on an analog-digital hybrid computer system. Results are given, indicating system performance as a function of sampling rate, computation delay, and system gains.
Digital realization of complex transfer functions
Authors: Fleischer Paul E. 
Published: March 2008

The need for realizing an arbitrary complex transfer func tion often arises in digital or hybrid simulation. A method for the optimal design of the digital implementation (equiv alent to a tapped delay line) of such transfer functions is presented. This procedure finds application in both purely digital and closed-loop hybrid simulations. In the latter case, the digital computer extends the capability and ca pacity of the analog computer and provides an efficient realization of complex transfer functions. Since the sampling frequencies for most simulations are run above the Nyquist rate, the procedure is designed to ignore the higher frequencies where signal energy is ab sent. In this fashion an optimum match to the desired characteristic can be achieved in the frequency band of interest. The procedure can fully compensate for degrada tions introduced by the hybrid sample-hold and recon struction method.
A hybrid computer technique for nonlinear function generation
Authors: Tutelman David M. 
Published: March 2008

The simulation of a physical system on an analog computer often requires the use of one or more nonlinear function generators. This paper describes a means by which a dig ital computer can be used to simulate the diode function generators of the analog computer in a closed-loop system. The digital computer program utilizes a table-lookup procedure to transform x into f(x). The table is previously prepared by the machine through linear interpolation be tween breakpoints. The breakpoints are the input data for the program. Many simulation problems need a nonlinear function generator as an element in a feedback loop. The digital computer introduces delay into the loop, rendering the simulation inaccurate and perhaps even unstable. A phase- advancing network must be included to compensate for the delay in the hybrid system. A simple and inexpensive technique for accomplishing the phase advance is analyzed and experimentally verified; the derivative of the incom ing waveform is used to predict the wave's value at some later instant of time. Advantages of the digital function generator include rapid setting, perfect reproducibility of functions, no limit on breakpoints, and an effective increase of the analog facility's nonlinear standby capability.
Toward a uniform simulation language
Authors: Augustin D.C. 
Published: March 2008

Real progress has been made by the SCi Committee on Simulation Software in their attempt to specify a "stand ard" language for the digital simulation of continuous systems. Their success, as indicated by the discussion dur ing the Hybrid Software Standardization Seminar at the SNSCi Meeting in Boston, surprised many who thought that the Committee was attempting to satisfy everybody- a proverbially impossible task. The SCi Committee on Simulation Software grew out of a general feeling that some sort of direction was needed in the area of "digital simulation languages". For many people, this feeling was crystallized by Brennan and Line barger's article "A survey of digital simulation ..." (Vol ume 3; Number 6, page 22, December 1964). The riot of invention duplicated effort and apparent neglect of good ideas indicated the need for some guidance and control! Most of the developers of important simulation lan guages joined in the committee work. They met at rather frequent intervals, maintained effective communication through correspondence, and at length reached a con sensus on principles and concepts. The detailed specifica tion of a continuous system simulation language was then delegated to a working subcommittee. They are now preparing a document, the subcommit tee's report, which will be modified and approved by the entire Committee on Simulation Software.
Hybrid simulation of the Apollo guidance and navigation system
Authors: Sullivan Madeline M. 
Published: March 2008

A hybrid simulation of the guidance and navigation system of the Apollo spacecraft is underway at the Massachusetts Institute of Technology Instrumentation Laboratory. The Apollo Guidance and Navigation equipment is digital, elec tronic, and electromechanical. The guidance and naviga tion analog and digital hardware is combined in simulation with analog and digital computers so that the hardware will be subjected to dynamic conditions approaching those found in a space environment. The instrumentation of the Apollo Guidance and Navi gation System is described as well as its adaptation to the hybrid simulation. Software models are discussed to indi cate some of the varied problems considered. Digital pro cedures which are designed to support the operator and enhance the reliability of the simulation are described. In conclusion, it becomes apparent that the judicious use of computers, together with guidance and navigation hardware and software, makes it possible to simulate in real time any part of the Apollo mission from lift-off to splash-down.
Simulating a jet gas turbine with an analog computer
Authors: Ahlbeck Donald R. 
Published: March 2008

In the past several years heavy emphasis has been placed on all-digital or hybrid simulation techniques in the analy sis of dynamic systems. To some the unmodified analog computer might seem as anachronistic as the narrow-gauge steam locomotive. Often, however, the demon Economics steps in; at this time the analog computer presents a most satisfactory compromise between accuracy, flexibility and cost. This article, Simulating a jet gas turbine with an analog computer, is a "case history" of such a dynamic system study. The prospect of an undetermined number of explo ratory runs, coupled with a limited foreknowledge of the system components, made the use of the analog computer (an EAI 31-R) attractive. With Battelle's current open-shop policy on analog computer use, the computer became, in effect, an extension of the engineer's slide rule. In spite of being Little Orphan Analog in a digital world, the machine performed admirably!
Methods of simulating structural dynamics
Authors: Ben Clymer A. 
Published: March 2008

This tutorial article is intended to convey the capability of simulating dynamically almost any structure by means of mathematical models of several types. It is intended also for reference. The article follows a building-block approach, starting with treatment of the basic structural elements: bars, straight beams, columns, curved beams, rods, plates, shells, and soil and foundations. Then methods of modeling an assembly of elements, as well as methods of assembling models of elements, are discussed. The methods covered include lumping, finite differenc ing, normal modes, and assumed modes. A road map is presented which shows many analytical routes from one type of model to another. It is shown that these methods may be regarded as special cases of the Lagrange assumed- mode method. Realization of this fact enhances under standing of each method and its relationships with other methods, thus affording a unified outlook upon the methods. Examples are given which point out both the impor tance of matching each assumed mode to every boundary condition and the remarkable accuracy of the resulting modal models.