Input Restrictions Research Articles

Estimating the elasticity of substitution between restricted and unrestricted inputs in a regulated fishery: A probit approach

Catch, effort, vessel, and skipper characteristic data for a sample of boats involved in the Tasmanian rock lobster fishery in the 1983/1984 season are used to estimate a fishing effort production function nested in a Cobb-Douglas fishery production function. The initial effort function is translog but tests suggest that the CES form cannot be rejected. The vessel's choice of fishing ground is modeled by a probit equation, the output from which is included in the OLS estimation of the production function. The elasticity of substitution between the inputs which are restricted by regulation and the other inputs is of particular interest as it determines whether input restriction is an efficient form of regulation for the fishery. The results suggest a value significantly less than unity.

Feeling Free Despite LBZ

Abstract It is sometimes argued that the occurrence of local brittle zones (LBZs) is a new phenomenon relevant only to modern low-carbon steels, while others claim that such LBZs are also present in the heat-affected zones of the C-Mn steels of the late sixties/seventies. In order to elucidate on this matter, both an “old” normalized (N) steel (1970s) and two modern low-carbon types of steel, normalized (N) and controlled rolled-accelerated cooled (CONRAC) have been investigated and compared with each other. In addition, consideration has been given to the correlation between the level of heat input during welding and the occurrence of local brittle zones. This has led in practice to a restriction of the heat input to 3.5 kJ/mm maximum for the modern low-carbon normalized steel investigated, which was used in recent projects. Furthermore, the engineering significance of LBZs is considered in the light of design aspects. It is concluded that there is little reason for concern with respect to a detrimental effect of LBZs in tubular connections of offshore structures, which is supported by a satisfactory performance of the latter to date.

Normovolaemic induced hypertension therapy for cerebral vasospasm after subarachnoid haemorrhage

We showed that normovolaemic induced hypertension therapy was effective in reducing ischaemic symptoms attributed to cerebral vasospasm in 41 patients after subarachnoid haemorrhage. By inducing hypertension to 25% to 50% above normal systolic arterial blood pressure, we observed that in 17 of 24 cases (71%) neurological deficits improved. In four cases of haemorrhagic infarction, the blood pressure rose to over 50% of systolic arterial pressure, and a low density area was confirmed on computerized tomography (CT) scan prior to vasospasm. Induced hypertension was therefore not considered when a low density area was revealed on CT scan. Restriction of fluid input is usually a factor in producing hypovolaemia after a neurosurgical operation. Intravascular volume expansion has been reported effective in reversing ischaemic deficits. However, according to Poiseuille's equation, increasing blood volume to a state of hypervolaemia can not enhance flow. The cerebral blood flow (CBF) was raised by increasing perfusion pressure, reducing viscosity, or increasing blood vessel diameter. Intravascular volume expansion elevates not only systemic arterial pressure, but also pulmonary artery wedge pressure over 18 mmHg and cardiac index over 2.2. Since pulmonary oedema and congestive heart failure may develop, one should monitor haemodynamic parameters with the Swan-Ganz catheter as a preventive measure. We emphasize that normovolaemic induced hypertension, maintaining haemodynamics subset 1 of the comparable haemodynamic subsets, is effective in raising perfusion pressure of CBF.

Two new ternary line codes

Two new ternary line codes are presented. Although the two codes are similar, they differ with respect to error propagation properties and power spectral densities. The codes are relatively simple, yet they satisfy tight channel input restrictions, making them suitable for use in practical base-band communications systems

THE FUTURE OF EEC DAIRY EXPORTS TO THE LESS‐DEVELOPED COUNTRIES: AGRICULTURAL ECONOMICS OF LONG‐RANGE PROJECTIONS AND MODEL STUDIES

From recent projection studies it can be concluded that future dairy exports by the EEC to the Less Developed Countries (LDCs) will increase. The self‐sufficiency ratio for dairy products in the EEC will increase because of strong, technologically induced, growth of production potential. On the one hand, surplus production in the EEC will be difficult to curtail as the unfavourable conditions of the general economy will impede outmigration of inputs. Import demand, on the other hand, is projected to increase as many populations will be moving into stages of higher growth of income. Thus, input restrictions of agriculture in industrialised countries may be unnecessary. In this paper some agricultural economic aspects of the implied trade relationships are discussed. It is concluded that LDCs are not likely to benefit from gains of trade as predicted by theory of free trade and international specialisation. From projections by model studies, however, no consensus emerged. Projection and model studies seem hardly suited to provide insight in the effects of international trade under conditions of imperfect competition.

The Impact of Input Regulation: The Case of the U. S. Dental Industry

THE analysis of input restrictions has been in large part limited to the impact of union jurisdictional rules or occupational licensure.1 There are, however, a significant number of cases where states have chosen to regulate the use of inputs in the production of particular products. Some examples include oyster harvesting, lobstering, medical practice, and dental practice. In some cases, these restrictions are justified on grounds of output limitation-for example, oyster harvesting and lobstering, in order to prevent overproduction due to common-property resource problems. In others, the regulations seem to be put in place to improve the returns to the residual income claimants in the industry being regulated-for example, medical and dental practices. Our analysis considers both restrictions on employment and restrictions on the functions that may be performed by labor inputs. It is demonstrated that, for either case, if the restrictions are effective, the marginal

Some Observations on Equivalence Handling Methods

The online disjoint set union problem is solved essentially by implementing two operations which manipulate disjoint sets. FIND(x) computes the name of the unique set of which x is a member. UNION(A,B) merges the two sets A and B into one new set named either A or B. Given a set of n elements, we may perform f ≥ n FIND's and n−1 intermixed UNION's in time 0(fα(f,n)) and space 0(n), where α(f,n) is related to a functional inverse of Ackermann's function and grows slowly. We show that certain modifications to the UNION operation that are convenient in some applications do not affect the running time complexity. We also show that under appropriate input restrictions, UNION and FIND can be made to run in linear time. However, the space required is 0(n+e), where e is the number of equivalence pairs to be processed.

Measurement of Allocative Biases of Production Control Policies

Because of growing stocks of grain and the reinstitution of production controls, the question of what allocative impacts such controls imply is once again relevant. The prospect that restrictions on land use may initiate an intensification in the use of substitute inputs such as fertilizer, which are already high in price, is discouraging. Although the issue is an old one, empirical evidence on the extent of these effects is incomplete.1 The purpose of this article is to derive a convenient means of measuring the allocative effects of changes in input restrictions. As an example of empirical application, results are presented which indicate the impact of acreage restrictions during the marketing quota years in North and South Dakota.

Ontogenesis of the Visual Cortex of Rabbits and the Effects of Visual Deprivation

Publisher Summary This chapter discusses the ontogenesis of the visual cortex of rabbits and the effects of visual deprivation. In the visual cortex of large postnatal developers, such as rats, cats, mice and rabbits, neuronal maturation and maturation of the laminar organization start around birth and show their main growth spurts prior to natural eye opening. This means that the driving factor for this development cannot be the normal visual input and that it is, therefore, unlikely that visual input has an important molding effect on the microstructural organization of the central visual brain regions. The fact that no, or only very few, degenerating neurons are seen during postnatal development and that the normally occurring decrease in neuron density can be accounted for by the increased volume of the various brain structures strengthens this conclusion. However, there is no redundancy during the growth of the nervous system. It may well be that neuroblasts are in excess during the prenatal proliferation phase and that some of them degenerate. There is good evidence that, in the peripheral nervous system, cell degeneration really occurs and is guided by the lack of sufficient synaptic sites. It can be said that cell degeneration induced by functional verification is unlikely to be a general phenomenon in the nervous system and almost certainly not in central visual brain regions. Evidence supporting this point of view comes from the studies on sensory input restriction.

Three-element reaction coordinates. III. Barrier curvature effects on intramolecular kinetic isotope effects

A study was made of the influence of curvature of the potential barrier on heavy-atom kinetic isotope effects calculated for reaction coordinates comprising nonzero displacements in three internal coordinates. Increase in barrier curvature may increase or decrease the isotope effect. In addition to the expected dependence on transition state bond force constants and geometry, reaction coordinate composition, and barrier curvature, the results depend in most cases on the specific selection of minor transition state force constants (required to meet the input restrictions of the method). Although chemically and physically reasonable choices of certain transition state parameters result in drastic reduction in redundancy of the output, further reduction depends on the development of criteria for assigning the barrier curvature and of rationale for selection of off-diagonal force constants. (auth)

The Simplification of Sequential Machines with Input Restrictions

A procedure is presented for simplifying the flow table of a sequential machine M when, in addition to the given flow table, it is specified that certain input sequences cannot occur. It is assumed that M receives its input from the output of another machine M, and that the restricted sequences are therefore those sequences that M, cannot generate.

Quantitative differences in performance on abstract discriminations using one or both hemispheres

Cats were trained to a stringent criterion on abstract two-choice visual pattern discriminations and were then tested with task information relayed to both hemispheres, or to only one hemisphere. Essentially normal, high-level response was possible with cue inputs to one eye only (the other occluded by a mask), even following section of the optic chiasm or the corpus callosum. If both structures were cut, so that unilateral inputs were restricted to one hemisphere, however, there was a sizable permanent decrease in accuracy of performance (accuracy under the bilateral inputs condition remained high). Performance on simple discrimination tasks, employing patterns with the same or greater acuity demands, was not affected by such restriction of inputs to one hemisphere. This finding, and the fact that some subjects can perform at a normal preoperative level after chiasm section, rule out explanation of the loss in single-hemisphere abstract task performance solely in terms of destruction of visual fibers. A more plausible interpretation of the results is provided in terms of a principle of cortical mass action, which assumes that the asymptotic level for performance on complex tasks may depend on the amount of cortex participating in the processing of task information.

Convolutional Transformation and Recovery of Binary Sequences

Abstract—This paper analyzes invertible length-preserving convolutional transformations of binary sequences, when the perfect inverse feedback transducer is replaced by a finite feedforward (i. e., convolutional) transducer which represents an approximation of the former. This replacement eliminates the error propagation effect, but the finiteness of the "inverse" transducer (decoder) results in a restriction on the input sequences, for which exact replication is achieved in the two-way transduction (transformation and recovery). The entity of the input restriction can be taken as a measure of performance for sets of transformations, and can be described in terms of the upper bound of the entropies of the binary sources which are "matched" to the system (direct and inverse transducers). This bound is clearly the capacity of the system viewed as a noiseless channel. It is shown that, if r is the number of decoder stages, the channel capacity has an asymptotic expression C≃1-Ab <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sup> , where the parameters b < 1 and A depend solely upon the structure of the set of resynchronizing states (RS cluster) possessed by the given set of transformations.

Bibliography of sensory and perceptual deprivation, isolation, and related areas.

This 1199-item bibliography is concerned with the general topics of sensory and perceptual deprivation, isolation, relative restriction of sensory input, brain-washing, life in isolated outposts, submarines, etc.

State table analysis of programs in an ALGOL-like language

a. The source language—SFD-ALGOL SFD-ALGOL 1.2 is an ALGOL-like language intended to describe the functions of synchronous systems. The function of a system is the response of its output to any input sequence. This function can be described by an algorithm. The algorithm need not be the one actually used by the system; it need only be equivalent. ALGOL is suitable for such a purpose except that it cannot express timing, specify input restrictions, or indicate which variables are input/output variables. SFD-ALGOL is identical to ALGOL-60 except for a few added declarations and an extra type of statement grouping known as a time block. The time block consists of statements enclosed within a time begin and the corresponding end, and is interpreted to mean that all actions indicated within it occur in the span of one clock pulse. Further details of SFD-ALGOL can be found in 2, a complete specification is supplied in 1. b. The object language—state tables The problem to be discussed here can be framed as follows: Given an SFD-ALGOL description of a finite state system produce the state transition table and output table of the system described. The state transition table (tabular form of the state diagram) has a row for every internal state, a column for every input state, and the entry at every intersection gives the next internal state that will occur in the system. The output table is of the same form, but contains the state of the output lines for each combination of internal and input states. A more complete treatment of finite state machine can be found in Gill 4. Each SFD-ALGOL description of a finite state system is actually a description of an infinite class of systems with equivalent* state tables. These systems cannot be distinguished on the basis of the I/O characteristics and, since an SFD-ALGOL program only describes I/O characteristics, it describes the whole class. The program or description itself has a state table, and it is this table that the process to be described derives. There exist effective algorithms that will reduce this table to the minimal possible table 3.4.

Canonical Form and Synthesis of Cellular Cascades

Cascades of two-input, one-output general function cells have been studied previously with the restriction that no external variable may drive more than one cell. Upon relaxing this restriction, it is shown that a variable that drives more than one cell in a cascade need never drive more than one cell that is not an EXCLUSIVE-OR cell, and that cell must be the first cell driven by the variable in the cascade. From this it follows that there exists a canonical form for cellular cascades with repeated inputs. Furthermore, the length of a cascade required to produce an n-variable function is bounded by (n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> +n-4)/2, and there are functions that meet this bound for all n. Derived from knowledge of the canonical form, a realizability and synthesis algorithm is described that is an extension of previously described algorithms. The algorithm has been used to test the 402 Harvard functions, and a table of minimal-length cascades of realizable functions is included in the paper. Although the number of realizable functions is greatly increased when the input restriction is relaxed, it is shown that the fraction of n-variable functions that are realizable becomes vanishingly small as n grows large. In particular, for example, of the 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n+1</sup> symmetric functions of n-variables, precisely 12 are realizable for all n≥3.

Input restriction and immediate memory decay in normal and subnormal children.

Twelve imbeciles and 12 normals, matched for their digit memory span, were presented with three digit numbers successively and simultaneously. Seven speeds of presentation were used. Each simultaneous speed of presentation had a corresponding successive speed. Subjects were required to recall digits on the conclusion of presentation of each number. Each performance was scored as the number of errors for each digit. With simultaneous presentations the difference between the groups was significant only at fast presentation speed, where the normals were significantly better than the imbeciles. Imbeciles improved at slow speeds and became as good as normals. In the case of successive presentations differences between groups occur only in relation to the second digit, which the normals remember better than the subnormals. Both groups remember the first digit worst as rates of presentation become progressively slower. Results are explained in terms of input restriction and of memory trace decay.

Optimum block codes for noiseless input restricted channels

A method for determining maximum-size block codes, with the property that no concatenation of codewords violates the input restrictions of a given channel, is presented. The class of channels considered is essentially that of Shannon (1948) in which input restrictions are represented through use of a finite-state machine. The principal results apply to channels of finite memory and codes of length greater than the channel memory but shorter codes and non-finite memory channels are discussed briefly. A partial ordering is first defined over the set of states. On the basis of this ordering, complete terminal sets of states are determined. Use is then made of Mason's general gain formula to obtain a generating function for the size of the code which is associated with each complete terminal set. Comparison of coefficients for a particular block length establishes an optimum terminal set and codewords of the maximum-size code are then obtained directly. Two important classes of binary channels are then considered. In the first class, an upper bound is placed on the separation of 1's during transmission while, in the second class, a lower bound is placed on this separation. Universal solutions are obtained for both classes.

Effects of fallout shelter confinement on family adjustment.

Introduction Man constantly thrusts himself into new and strange environments, the unusual nature of which often makes special demands on his resources. For example, in recent years humans have been called upon to function for prolonged periods at a high level of proficiency in submerged nuclear submarines, or more recently, in a capsule in space. Such special environments have in common the imposition of a monotonous daily routine, restriction of physical movement, disruption of normal social interaction and stimulation, and introduction of unusual routines of sleep, feeding, etc. A series of experiments beginning with the work of Hebb and his associates, Bexton, Heron, and Scott, 1 and summarized recently by Solomon et al., 7 have demonstrated that sharp restriction of meaningful sensory input and imposition of a monotonous, patternless routine can be a disrupting experience for some individuals. These experiments, generally summarized under the term

Heat Transfer to Fully Developed Laminar Flow in a Circular Tube With Arbitrary Circumferential Heat Flux

A solution is presented for fully developed laminar heat transfer in a circular tube with arbitrary circumferential heat flux. Examples included indicate that the influence of circumferential heat-flux variation on wall temperatures can be quite significant and provide some insight into the nature of the effects. The analysis allows calculation of wall temperatures for any arbitrary peripheral heat-flux variation for fully developed laminar flow under the restriction of constant axial heat input.