David Samuel - Academia.edu (original) (raw)
Papers by David Samuel
Journal of the Chemical Society (Resumed), 1954
Psychopharmacologia, 1976
Rats implanted with bipolar electrodes aimed at the medial forebrain bundle (MFB) were trained to... more Rats implanted with bipolar electrodes aimed at the medial forebrain bundle (MFB) were trained to self-stimulate. Six daily injections of 2 mEq/kg of the chloride salts of Li+, Rb+ or Cs+ were administered and the rate of intracranial self-stimulation (ICSS) was recorded. Lithium caused a reversible decrease in ICSS rate, beginning on the second day and returning to pretreatment rate on the fourth day of injections. The decrease was more pronounced in animals with high baseline rate (over 500 responses/10 min) than in low responders. Rubidium enhanced ICSS rate whereas cesium had no effect. These results agree with other accumulating data showing the opposite effects of Li+ and Rb+, but their relevance to effective disorders is not clear.
Journal of the Chemical Society (Resumed), 1964
The rate of isotopic exchange of oxygen between phosphorous acid and water was measured over the ... more The rate of isotopic exchange of oxygen between phosphorous acid and water was measured over the range from pH 10 to 9.4N-HClO/sub 4/. The observed rate of exchange increases continuously with increasing acidity. The rate constants for the exchange between water and the various ionic species present at different pH's were calculated and the mechanisms of the exchange discussed. (auth)
Studies in Educational Evaluation, 1976
ABSTRACT
Science Education, 1974
Low enrollments in the physical sciences have been a professional concern for some time, primaril... more Low enrollments in the physical sciences have been a professional concern for some time, primarily because of their adverse effect on the general education of high school students, but also because of their possible impact on vocational choice, notably that of potential teachers [ 1 ]. Several studies attempted to identify the reasons for this phenomenon. Cooley has found that the greatest loss from the "potential scientist pool" (students planning careers in science and engineering) occurs in the eleventh and twelfth grades [ 2 ]. This has been rightly interpreted to mean that "secondary chemistry and physics courses are screening out potential science majors" [Ref. 1, p. 3241. The following explanations have been offered for this "screening out" process: The scarcity of qualified teachers [3,4, 51. The nature of the physical science course content [6]. The "difficulty" of courses in the physical sciences [7, 81. The severity of grading by physics teachers [9, 101. Characteristics and attitudes of physics teachers [ 1 1, 121. Dissatisfaction developed while taking high school physics courses [ 13, 141. The tendency to look at school variables in order to find a possible explanation for the decrease in physics enrollment is quite understandable. Even when the findings of a carefully designed study "do not appear to support the idea that grading practices of the high school physics teacher is discouraging students away from enrolling in a high school physics course" [Ref. 15, p. 281, the authors of that study, looking for a more fruitful area, suggest another school variable, namely, "what the physics teachers are doing in the classroom" (on. cit.). The purpose of the present study is to identify a wider range of factors which may be associated with the attitudes of high school students towards physics. While Israeli students are undoubtedly different from either American or Australian students, the same trend towards declining enrollments in high school as well as in college physics noted in these two countries prevail in Israel too. In Israel, all the students study the same topics in the 9th and the 10th grade. At the end of the 10th grade they elect to study one of the several specialized curricula in the 11th and 12th grades. Each such specialized curriculum (called "Megama") concentrates on a major field of study such as Social Sciences, Biology, Humanities, Physics-Mathematics, and Arabic Studies. This structure of the educational system has two advantages for our study: 75
Science Education, 1977
Science Education 61 (3): 41 5-422 (I 977) 0 I977 by John Wiley & Sons, Inc.
Psychopharmacology, 1979
In a study of the mechanisms controlling the learned helplessness phenomenon, rats were exposed t... more In a study of the mechanisms controlling the learned helplessness phenomenon, rats were exposed to either inescapable preshocks or control procedures, treated with one of three dosages of desmethylimipramine, and tested for later adaptive responding. This catecholamine modulator attenuated the deficits in escape responding that ordinarily follow prior exposure to inescapable preshocks, and it did so in a dose-dependent fashion. These findings support the position that the learned helplessness phenomenon is mediated by catecholamine changes.
Pharmacology Biochemistry and Behavior, 1975
![Research paper thumbnail of Novel ring chemistry of vitamin B6 with singlet oxygen and an activated ene: isolated products and identified intermediates suggesting an operable [3 + 2] cycloaddition](https://attachments.academia-assets.com/115785822/thumbnails/1.jpg)
](Organic & Biomolecular Chemistry, 2012
Pyridoxine hydrochloride (2.10 g, 10.2 mmol) and Rose Bengal (17 mg) were dissolved in phosphate ... more Pyridoxine hydrochloride (2.10 g, 10.2 mmol) and Rose Bengal (17 mg) were dissolved in phosphate buffer (280 mL, 0.25 M, pH 7.5). The resulting solution was sparged with oxygen and irradiated with light (see General Methods) for 4 hours at room temperature. The mixture of products was lyophilized and purified via column chromatography on silica gel (15% MeOH in CH 2 Cl 2). The fractions containing the major product yielded a white solid (0.89 g, 43%). The
Animal Learning & Behavior, 1981
Journal of Research in Science Teaching, 1980
Journal of Research in Science Teaching, 1977
It is fairly well established that the objectives of science curricula can be divided into three ... more It is fairly well established that the objectives of science curricula can be divided into three major areas, namely, cognitive, affective, and psychomotor domains (Bloom, 1956). In science curricula, practical work (which is mainly in the psychomotor domain) assumes an important role (Shulman & Tamir, 1973). However, while laboratory-centered activities are perhaps the most significaut aspects of these curricula, "The development of psychomotor skills has been alnrost eomplately ignored by researchers in science education" (Ramsey & Howe, 1969). Although in the last few years several attempts have been made to incorporate practical examinations into evaluation projects (Kelly & Lister, 1969; Tamir, 1974), "The research on the relations between laboratory and other learning modes m a i n s scarce" (Shulman & Tamir, 1973).
Journal of Neuroscience Research, 1975
Journal of Chemical Education, 1978
Journal of Chemical Education, 1982
ABSTRACT
IEEE Transactions on Nuclear Science, 1970
ABSTRACT The use of small solid state detectors for behavioral studies is described. These detect... more ABSTRACT The use of small solid state detectors for behavioral studies is described. These detectors can be inserted in holders cemented to the skull of freely moving animals thus enabling the determination of uptake of radioactive matermal in an area of the brain. By injecting P32 labelled Na3PO4, the rate of incorporation of phosphate in the brain under different behavioral conditions such as sleep anesthesia, learning, etc. can be followed. The advantages of this method are the repeated measurements on the same animal, the use of live animals for both psychological and physiological studies, the possibility of kinetic and turnover studies in the brain, blood, and in principle, other organs. Using the uptake of P32 together with studies involving other isotopes such as the stable isotope O18, an estimate of the energyrequirements of the brain can be made. The detector is a lithium drifted silicon device mounted in an electroform nickel tube of 2mm O.D. and a wall thickness of ¿ 25 microns. The detector is coated with 3 microns of parylene and secured in the nickel tube with an RTV potting compound. The major components of the preamplifier are: an FET, a transistor, three resistors and three capacitors mounted behind the detector in the probe. Performance characteristics and results will be described.
Hormones and Behavior, 1978
Abstract Young frogs, Xenopus laevis, raised on a white background showed a slight preference for... more Abstract Young frogs, Xenopus laevis, raised on a white background showed a slight preference for the black background of a black-white preference testing apparatus. Keeping frogs for either 24 hr or 20 days on a black background resulted in a further increase in their preference for black. Injecting 1 μg of synthetic α-MSH into white-adapted frogs had no effect on their black-white preference. On the other hand, Xenopus laevis tadpoles, at an early stage of metamorphosis, raised on a white background showed a significant preference for white. Keeping these tadpoles for 24 hr on a black background resulted in a shift from white to black preference. Injecting synthetic α-MSH into white-adapted tadpoles resulted in an increase in their preference for black. A behavioral feedback mechanism appears to exist between the release of endogenous MSH when a tadpole is exposed to a black background and its subsequent preference for background color.
European Journal of Pharmacology, 1978
Brain Research, 1976
Antisynaptosomal plasma membrane antibodies were introduced through an infusion cannula into rat ... more Antisynaptosomal plasma membrane antibodies were introduced through an infusion cannula into rat brain and their effects on behaviour were tested. Fourdifferent learning paradigms were used, two appetitively and two aversively motivated, to show impairment in memory retrieval. No effects were found on aquisition, motor activity, or motivation.
Biochimica et Biophysica Acta, 1962
Journal of the Chemical Society (Resumed), 1954
Psychopharmacologia, 1976
Rats implanted with bipolar electrodes aimed at the medial forebrain bundle (MFB) were trained to... more Rats implanted with bipolar electrodes aimed at the medial forebrain bundle (MFB) were trained to self-stimulate. Six daily injections of 2 mEq/kg of the chloride salts of Li+, Rb+ or Cs+ were administered and the rate of intracranial self-stimulation (ICSS) was recorded. Lithium caused a reversible decrease in ICSS rate, beginning on the second day and returning to pretreatment rate on the fourth day of injections. The decrease was more pronounced in animals with high baseline rate (over 500 responses/10 min) than in low responders. Rubidium enhanced ICSS rate whereas cesium had no effect. These results agree with other accumulating data showing the opposite effects of Li+ and Rb+, but their relevance to effective disorders is not clear.
Journal of the Chemical Society (Resumed), 1964
The rate of isotopic exchange of oxygen between phosphorous acid and water was measured over the ... more The rate of isotopic exchange of oxygen between phosphorous acid and water was measured over the range from pH 10 to 9.4N-HClO/sub 4/. The observed rate of exchange increases continuously with increasing acidity. The rate constants for the exchange between water and the various ionic species present at different pH's were calculated and the mechanisms of the exchange discussed. (auth)
Studies in Educational Evaluation, 1976
ABSTRACT
Science Education, 1974
Low enrollments in the physical sciences have been a professional concern for some time, primaril... more Low enrollments in the physical sciences have been a professional concern for some time, primarily because of their adverse effect on the general education of high school students, but also because of their possible impact on vocational choice, notably that of potential teachers [ 1 ]. Several studies attempted to identify the reasons for this phenomenon. Cooley has found that the greatest loss from the "potential scientist pool" (students planning careers in science and engineering) occurs in the eleventh and twelfth grades [ 2 ]. This has been rightly interpreted to mean that "secondary chemistry and physics courses are screening out potential science majors" [Ref. 1, p. 3241. The following explanations have been offered for this "screening out" process: The scarcity of qualified teachers [3,4, 51. The nature of the physical science course content [6]. The "difficulty" of courses in the physical sciences [7, 81. The severity of grading by physics teachers [9, 101. Characteristics and attitudes of physics teachers [ 1 1, 121. Dissatisfaction developed while taking high school physics courses [ 13, 141. The tendency to look at school variables in order to find a possible explanation for the decrease in physics enrollment is quite understandable. Even when the findings of a carefully designed study "do not appear to support the idea that grading practices of the high school physics teacher is discouraging students away from enrolling in a high school physics course" [Ref. 15, p. 281, the authors of that study, looking for a more fruitful area, suggest another school variable, namely, "what the physics teachers are doing in the classroom" (on. cit.). The purpose of the present study is to identify a wider range of factors which may be associated with the attitudes of high school students towards physics. While Israeli students are undoubtedly different from either American or Australian students, the same trend towards declining enrollments in high school as well as in college physics noted in these two countries prevail in Israel too. In Israel, all the students study the same topics in the 9th and the 10th grade. At the end of the 10th grade they elect to study one of the several specialized curricula in the 11th and 12th grades. Each such specialized curriculum (called "Megama") concentrates on a major field of study such as Social Sciences, Biology, Humanities, Physics-Mathematics, and Arabic Studies. This structure of the educational system has two advantages for our study: 75
Science Education, 1977
Science Education 61 (3): 41 5-422 (I 977) 0 I977 by John Wiley & Sons, Inc.
Psychopharmacology, 1979
In a study of the mechanisms controlling the learned helplessness phenomenon, rats were exposed t... more In a study of the mechanisms controlling the learned helplessness phenomenon, rats were exposed to either inescapable preshocks or control procedures, treated with one of three dosages of desmethylimipramine, and tested for later adaptive responding. This catecholamine modulator attenuated the deficits in escape responding that ordinarily follow prior exposure to inescapable preshocks, and it did so in a dose-dependent fashion. These findings support the position that the learned helplessness phenomenon is mediated by catecholamine changes.
Pharmacology Biochemistry and Behavior, 1975
Organic & Biomolecular Chemistry, 2012
Pyridoxine hydrochloride (2.10 g, 10.2 mmol) and Rose Bengal (17 mg) were dissolved in phosphate ... more Pyridoxine hydrochloride (2.10 g, 10.2 mmol) and Rose Bengal (17 mg) were dissolved in phosphate buffer (280 mL, 0.25 M, pH 7.5). The resulting solution was sparged with oxygen and irradiated with light (see General Methods) for 4 hours at room temperature. The mixture of products was lyophilized and purified via column chromatography on silica gel (15% MeOH in CH 2 Cl 2). The fractions containing the major product yielded a white solid (0.89 g, 43%). The
Animal Learning & Behavior, 1981
Journal of Research in Science Teaching, 1980
Journal of Research in Science Teaching, 1977
It is fairly well established that the objectives of science curricula can be divided into three ... more It is fairly well established that the objectives of science curricula can be divided into three major areas, namely, cognitive, affective, and psychomotor domains (Bloom, 1956). In science curricula, practical work (which is mainly in the psychomotor domain) assumes an important role (Shulman & Tamir, 1973). However, while laboratory-centered activities are perhaps the most significaut aspects of these curricula, "The development of psychomotor skills has been alnrost eomplately ignored by researchers in science education" (Ramsey & Howe, 1969). Although in the last few years several attempts have been made to incorporate practical examinations into evaluation projects (Kelly & Lister, 1969; Tamir, 1974), "The research on the relations between laboratory and other learning modes m a i n s scarce" (Shulman & Tamir, 1973).
Journal of Neuroscience Research, 1975
Journal of Chemical Education, 1978
Journal of Chemical Education, 1982
ABSTRACT
IEEE Transactions on Nuclear Science, 1970
ABSTRACT The use of small solid state detectors for behavioral studies is described. These detect... more ABSTRACT The use of small solid state detectors for behavioral studies is described. These detectors can be inserted in holders cemented to the skull of freely moving animals thus enabling the determination of uptake of radioactive matermal in an area of the brain. By injecting P32 labelled Na3PO4, the rate of incorporation of phosphate in the brain under different behavioral conditions such as sleep anesthesia, learning, etc. can be followed. The advantages of this method are the repeated measurements on the same animal, the use of live animals for both psychological and physiological studies, the possibility of kinetic and turnover studies in the brain, blood, and in principle, other organs. Using the uptake of P32 together with studies involving other isotopes such as the stable isotope O18, an estimate of the energyrequirements of the brain can be made. The detector is a lithium drifted silicon device mounted in an electroform nickel tube of 2mm O.D. and a wall thickness of ¿ 25 microns. The detector is coated with 3 microns of parylene and secured in the nickel tube with an RTV potting compound. The major components of the preamplifier are: an FET, a transistor, three resistors and three capacitors mounted behind the detector in the probe. Performance characteristics and results will be described.
Hormones and Behavior, 1978
Abstract Young frogs, Xenopus laevis, raised on a white background showed a slight preference for... more Abstract Young frogs, Xenopus laevis, raised on a white background showed a slight preference for the black background of a black-white preference testing apparatus. Keeping frogs for either 24 hr or 20 days on a black background resulted in a further increase in their preference for black. Injecting 1 μg of synthetic α-MSH into white-adapted frogs had no effect on their black-white preference. On the other hand, Xenopus laevis tadpoles, at an early stage of metamorphosis, raised on a white background showed a significant preference for white. Keeping these tadpoles for 24 hr on a black background resulted in a shift from white to black preference. Injecting synthetic α-MSH into white-adapted tadpoles resulted in an increase in their preference for black. A behavioral feedback mechanism appears to exist between the release of endogenous MSH when a tadpole is exposed to a black background and its subsequent preference for background color.
European Journal of Pharmacology, 1978
Brain Research, 1976
Antisynaptosomal plasma membrane antibodies were introduced through an infusion cannula into rat ... more Antisynaptosomal plasma membrane antibodies were introduced through an infusion cannula into rat brain and their effects on behaviour were tested. Fourdifferent learning paradigms were used, two appetitively and two aversively motivated, to show impairment in memory retrieval. No effects were found on aquisition, motor activity, or motivation.
Biochimica et Biophysica Acta, 1962