Yedidyah Langsam

Pediatric nerve agent poisoning: medical and operational considerations for emergency medical services in a large American city.

Abstract: Most published recommendations for treatment of pediatric nerve agent poisoning are based on standard resuscitation doses for these agents. However, certain medical and operational concerns suggest that an alternative approach may be warranted for treatment of children by emergency medical personnel after mass chemical events. (1) There is evidence both that suprapharmacological doses may be warranted and that side effects from antidote overdosage can be tolerated. (2) There is concern that many emergency medical personnel will have difficulty determining both the age of the child and the severity of the symptoms. Therefore, the Regional Emergency Medical Advisory Committee of New York City and the Fire Department, City of New York, Bureau of Emergency Medical Services, in collaboration with the Center for Pediatric Emergency Medicine of the New York University School of Medicine and the Bellevue Hospital Center, have developed a pediatric nerve agent antidote dosing schedule that addresses these considerations. These doses are comparable to those being administered to adults with severe symptoms and within limits deemed tolerable after inadvertent nerve agent overdose in children. We conclude that the above approach is likely a safe and effective alternative to weight-based dosing of children, which will be nearly impossible to attain under field conditions.

THE REPRESENTATION OF CONSTITUENT STRUCTURES FOR FINITE-STATE PARSING

A mixed prefix-postfix notation for representations of the constituent structures of the expressions of natural languages is proposed, which are of limited degree of center embedding if the original expressions are noncenter-embedding. The method of constructing these representations is applicable to expressions with center embedding, and results in representations which seem to reflect the ways in which people actually parse those expressions. Both the representations and their interpretations can be computed from the expressions from left to right by finite-state devices.The class of acceptable expressions of a natural language L all manifest no more than a small, fixed, finite degree n of center embedding. From this observation, it follows that the ability of human beings to parse the expressions of L can be modeled by a finite transducer that associates with the acceptable expressions of L representations of the structural descriptions of those expressions. This paper considers some initial steps in the construction of such a model. The first step is to determine a method of representating the class of constituent structures of the expressions of L without center embedding in such a way that the members of that class themselves have no more than a small fixed finite degree of center embedding. Given a grammar that directly generates that class of constituent structures, it is not difficult to construct a deterministic finite-state transducer (parser) that assigns the appropriate members of that class to the noncenter-embedded expressions of L from left to right. The second step is to extend the method so that it is capable of representing the class of constituent structures of expressions of L with no more than degree n of center embedding in a manner which appears to accord with the way in which human beings actually parse those sentences. Given certain reasonable assumptions about the character of the rules of grammar of natural languages, we show how this step can also be taken.

Automatic generation of graphic displays of data structures through a preprocessor

Recent attention has been given to graphic display routines that allow the programmer to observe the effects of applications programs on various data structures. Much of the work reported in the literature has involved the animation of specific algorithms and has necessitated manual effort by programmers on an application by application basis. Results of initial work in developing a general purpose tool for the display of data structures have already been published. In order to make the tool more widely used and more flexible it is necessary that some type of automatic processing be provided to allow for the generation of the graphic display routines themselves. Initial work in this area and further avenues of research are discussed.

Preposition-phrase attachment in noun phrases

This paper examines the ambiguity of noun phrases (NPs) with postmodifying preposition phrases (PPs), such as “the triangle next to the circle below the square.” This ambiguity is attributable in part to the difference in attachment sites for the second PP. If it attaches low, it modifies just the NP that is the object of the first preposition, and the resulting structure is right branching. If it attaches high, it modifies the entire preceding NP, and the resulting structure is left branching. However, each of these structures itself has two distinct interpretations. In the case of the high-attachment structure, these different interpretations have been previously noted; we call them stacking and coordinating. In the stacking interpretation, each PP modifies the entire NP to its left, whereas in the coordinating interpretation, it modifies just the head noun to its left (the first noun in the construction). In the case of the low-attachment structure, only the interpretation corresponding to the coordinating one has been noted; we call it alternating. However, a fourth distinct interpretation is possible, which corresponds to the stacking interpretation of the highattachment structure; we call it stuffing. In the alternating interpretation, each preposition has scope only over the head of the NP that is its complement. In the stuffing interpretation, each preposition has scope over its entire complement. In a pilot study, we found that the interpretations based on low attachment are preferred to those based on high attachment by a 2∶1 ratio. Of the two low-attachment interpretations, alternating is preferred to stuffing by a 20∶1 ratio. However, of the two high-attachment interpretations, coordinating is preferred to stacking by only a 2∶1 ratio. In a second pilot study, we examined the pattern of interpretations of phrases with four PP postmodifiers of an NP, which in principle have 112 distinct interpretation types. Eleven of these types were noted in the experimental materials. We provide a detailed analysis of these types and note that the relative preference of the various interpretations found in the first study is preserved.

Laser induced vibrational energy transfer in iron pentacarbonyl

The internal kinetics of Fe(CO)5 as well as the kinetics between Fe(CO)5 and other nonreactive species were studied using the technique of laser induced fluorescence. The energy transfer behavior of this large polyatomic is discussed in terms of existing V–V and V‐T/R theories and collisional energy transfer. Iron pentacarbonyl’s vibrational energy structure is treated by means of a simple three and four level energy transfer scheme. Subsequent to excitation of the 10 μ region by a CO2 laser, infrared fluorescence has been detected from the ∼16, ∼5, and ∼4 μ regions of Fe(CO)5. A single exponential decay rate of 13.6 ms−1 Torr−1 is observed from the ∼5 μ region, in good agreement with other decay rates established for smaller polyatomics possessing similar vibrational level structure. Under conditions of low fluence (∼30 mJ/cm2), this region is activated at a rate of 474 ms−1 Torr−1 suggesting a rapid near resonant collisional energy transfer. Under conditions of high fluence (∼5 J/cm2), the activation of...

A New Method of Representing Constituent Structuresa

The class of acceptable expressions (with no restrictions on length) of a natural language appears to form a regular set. The class of grammatical structures that corresponds to that class of expressions, however, does not, if those structures are represented in tree or bracketing form. We propose a parenthesis-free method of representing grammatical structures which permits the class that corresponds to the acceptable expressions of a natural language to constitute a regular set. The results of this method can be considered the basis of a viable model of human representation of grammatical structure for two reasons. First, the grammatical structures of acceptable expressions may be computed in tandem with the processing of those expressions from left to right; and, second, this computation can itself be carried out by a finite automaton. We apply this method to a fragment of English and show how it works for that fragment. A portion of this application has been implemented in PL/I.

Teching PL/I using a microcomputer

Until the Fall 1983 semester, the introductory programming course at Brooklyn College had been taught (in the PL/C dialect of PL/I) using keypunch equipment in a batch environment. However, that term two experimental sections used IBM Personal Computer (PCs) instead of keypunches. The experiment was expanded in the Spring 1984 semester to include almost one third of all sections of the introductory course, and then expanded again in the Fall 1984 semester to all sections of the first PL/I course, plus three sections of second-level courses. Although the PCs were quite easy to use, the PL/I-86 PC-DOS compiler produced by Digital Research caused many problems. A number of advantages and disadvantages of the experiment are discussed. Other implications of the use of PCs are also noted, including the possible change of language and the extension to more advanced courses in the curriculum.