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Showing papers by "University of New Hampshire published in 1983"


Journal ArticleDOI
TL;DR: Learned behavior varies in its resistance to change, depending on the rate of reinforcement, which may be characterized as behavioral momentum, which in turn may be analyzed into terms corresponding to mass and velocity in classical physics.
Abstract: Learned behavior varies in its resistance to change, depending on the rate of reinforcement. Resistance to change may be characterized as behavioral momentum, which in turn may be analyzed into terms corresponding to mass and velocity in classical physics. Behavioral mass may be inferred from changes in response rate when experimental conditions are altered. Relevant data were obtained by training pigeons to peck a key on two-component multiple variable-interval, variable-interval schedules. Six pigeons were studied on three pairs of variable-interval schedules in all possible orders. When performance stabilized, resistance to change was assessed by arranging response-independent food during periods between components and by extinction. For each operation, the data for all schedule performances converged onto a single function, permitting estimation of the ratio of behavioral masses for each pair of schedules. The response-independent food data suggested that the ratio of behavioral masses is a power function of the ratio of reinforcement rates and that behavioral mass may be measured on a ratio scale.

425 citations


Book ChapterDOI
01 Jan 1983
TL;DR: There is ample evidence that vanadium in the body exists primarily as the vanadyl(IV) ion, VO2+, complexed to proteins and other cellular components; several biological reducing agents can convert vanadium(V) to this form.
Abstract: Vanadium is an essential element. It is found widely distributed in minor and trace amounts throughout the lithosphere and biosphere. Vanadium is present in all mammalian tissues at concentrations of about 10 µM or less. Numerous physiological effects of this element are known at both the organismic and cellular levels, and in some instances these effects can be explained in terms of its biochemistry. Vanadate(V) and/or vanadyl(IV) ions are very potent inhibitors (K1 ≲ 10−6 M) of certain phosphatases, ATPases, phosphotransferases, nucleases, and kinases, among others. Vanadate(V) activates adenylate kinase. These ions have been quite useful as kinetic and spectroscopic (EPR) probes of complex cellular processes. Vanadium is an insulin mimetic agent. The ability of vanadium at low concentrations to influence enzymes is probably important to its function in vivo. Much of the biochemistry of vanadium is intricately related to the redox and coordination chemistry of this element. In particular, the parallel between the chemistries of vanadates and phosphates can account for the observed inhibition of various phosphohydrolases. However, there is ample evidence that vanadium in the body exists primarily as the vanadyl(IV) ion, VO2+, complexed to proteins and other cellular components; several biological reducing agents can convert vanadium(V) to this form. Serum transferrin appears to be involved in the metabolism of vanadium, perhaps as the transport protein for VO2+. Despite recent major advances in our understanding of the biochemistry of vanadium, the delineation of the physiological function(s) of this important element has remained an elusive goal.

278 citations


Journal ArticleDOI
TL;DR: This paper developed Weick's notion of complicated understanding by linking it with concepts of complementarity, cognitive complexity, and adult development and described a rationale for, and design elements of, management education programs aimed at increasing complicated understanding in administrators, primarily by fostering differentiation and integration of perspectives on organizational problems.
Abstract: This paper develops Weick's (1979) notion of “complicated” understanding by linking it with concepts of complementarity, cognitive complexity, and adult development The paper describes a rationale for, and design elements of, management education programs aimed at increasing complicated understanding in administrators, primarily by fostering differentiation and integration of perspectives on organizational problems It suggests several outcomes of complicated understanding and indicates ways in which these outcomes, as well as programs aimed at producing them, can be assessed

277 citations


Journal ArticleDOI
09 Dec 1983-Science
TL;DR: Deforestation appears to be the dominant biotic effect on atmospheric carbon dioxide; the possibilities for limiting the accumulation of carbon dioxide in the atmosphere through reduction in use of fossil fuels and through management of forests may be greater than is commonly assumed.
Abstract: A study of effects of terrestrial biota on the amount of carbon dioxide in the atmosphere suggests that the global net release of carbon due to forest clearing between 1860 and 1980 was between 135 x 10(15) and 228 x 10(15) grams. Between 1.8 x 10(15) and 4.7 x 10(15) grams of carbon were released in 1980, of which nearly 80 percent was due to deforestation, principally in the tropics. The annual release of carbon from the biota and soils exceeded the release from fossil fuels until about 1960. Because the biotic release has been and remains much larger than is commonly assumed, the airborne fraction, usually considered to be about 50 percent of the release from fossil fuels, was probably between 22 and 43 percent of the total carbon released in 1980. The increase in carbon dioxide in the atmosphere is thought by some to be increasing the storage of carbon in the earth's remaining forests sufficiently to offset the release from deforestation. The interpretation of the evidence presented here suggests no such effect; deforestation appears to be the dominant biotic effect on atmospheric carbon dioxide. If deforestation increases in proportion to population, the biotic release of carbon will reach 9 x 10(15) grams per year before forests are exhausted early in the next century. The possibilities for limiting the accumulation of carbon dioxide in the atmosphere through reduction in use of fossil fuels and through management of forests may be greater than is commonly assumed.

258 citations


Journal ArticleDOI
TL;DR: It is shown that if the heart can be considered to be bounded by a closed surface, then the value of φm on this surface is uniquely related to the surface electrocardiogram to within a constant, provided there are no internal discontinuities.
Abstract: Cardiac muscle is considered to consist of an intracellular domain and an exracellular or interstitial domain. Current passes from one domain to the other through the cell membrane. Electric potentials in interstitial space are shown to be associated with current sources proportional to the spatial gradient of the cellular transmembrane action potential, φ m . Hence, given the distribution of φ m throughout the myocardium, one can calculate the surface electrocardiogram and extracorporeal magnetocardiogram. The problem is considerably complicated when anisotropy is considered. If interstitial space is approximately isotropic, however, the sources are still proportional to ∇φ m . It is shown that the effects of intracellular anisotropy on the surface electrocardiogram may be relatively small. The inverse problem is discussed briefly, with consideration of the relationship of the magnetocardiogram to the electrocardiogram. Finally, it is shown that if the heart can be considered to be bounded by a closed surface, then the value of φ m on this surface is uniquely related to the surface electrocardiogram to within a constant, provided there are no internal discontinuities. Such discontinuities, however, would be expected to occur in cases of ischemia and necrosis.

253 citations


Journal ArticleDOI
01 Feb 1983-Ecology
TL;DR: In this article, a synthesis based on data generated by the International Biological Pro- gram (IBPG) deals with the relationships among biotic and abiotic factors at the ecosystem level.
Abstract: This paper, a synthesis based on data generated by the International Biological Pro- gram, deals with the relationships among biotic and abiotic factors at the ecosystem level. Emphasis is placed on aboveground net primary production (ANPP), a major component of energy that drives ecosystem processes, and on potential evapotranspiration (PET), the abiotic variable most often used to explain variation in ANPP. The question addressed is: can ANPP be related to combinations of biotic and abiotic factors such that the relationships are independent of ecosystem type, whether it be forest, grassland, or desert'? ANPP as a function of peak foliar standing crop (FSC) was best explained by models which showed a reduction in ANPP/FSC as FSC increased. Thus, deserts had a higher ANPP per unit of FSC than did other systems. As expected, photosynthetic efficiency (PE) was highest for forests, -ZOO times greater than for deserts. However, when PE was evaluated per unit of foliage, the differences in PE of ecosystems were much less. In fact, a hot-desert site had the highest PE/FSC. In terms of a theoretical maximum, the PE of forests was only 6-25% of the maximum value. Systems with nearly steady-state aboveground standing crop (ASC) showed an exponential decrease with decreased water availability (potential evapotranspiration minus precipitation). For these same systems, the ratio of ANPP to ASC increased with decreased water availability, suggesting that water-stressed systems need more energy from ANPP to drive internal processes. A model predicting ANPP of desert-shortgrass steppes was structured in terms of FSC, water availability, and temperature. The predictive power was found to be very highs and the model was successfully validated in two of three cases with an independent data set. A model predicting ANPP of forests was structured in terms of FSC, radiation, ASC, and temperature. The deviation of the observed ANPP relative to that calculated was 17%. Deviations from predicted values were highest for deciduous stands with high ANPP and low FSC. Most relationships exhibited good correlations between ANPP and the various independent vari- ables including both biotic, abiotic, and combinations of the two. However, in many instances the data tended to be grouped by ecosystem type, suggesting that variation in ANPP can be reduced if ecosystem type is an added independent variable. It was surprising to find that, with the limits of our data, differences in ANPP at the ecosystem level are not glaring, especially considering that soil factors were not included in our analyses. When considering the broad range of genotypes in each ecosystem, and the much broader genotypic range representing all ecosystems, the control that native ecosystems have over abiotic factors in producing ANPP is evident but not large.

212 citations


Journal ArticleDOI
TL;DR: Using Mossbauer resonance spectroscopy of 57Fe, this article determined the nature and distribution of major iron compounds in the magnetotactic bacterium Aquaspirillum magnetotoracticum.

193 citations


Journal ArticleDOI
TL;DR: Analysis of data on 6,096 cases of child sexual abuse which were "officially reported" in 1978 shows that foster placement occurred in more cases of sexual abuse than physical abuse, and was concentrated among cases of older children who reported their own victimization.

161 citations


Journal ArticleDOI
22 Sep 1983-Nature
TL;DR: In this article, the relative starting times of the energetic ion and electron interactions were examined for two gamma ray and electron bremsstrahlung X-ray emitting solar flares, on June 7 and 21, 1980.
Abstract: Data from the observations of two gamma ray and electron bremsstrahlung X-ray emitting solar flares, on June 7 and 21, 1980, were used to examine the relative starting times of the energetic ion and electron interactions The data were gathered by the SMM, which was viewing the 2223 MeV line from H-1(n, gamma)H-2, the 0511 MeV line from electron-positron annihilation, the prompt nuclear lines at 444 and 613 MeV from excited C-12 and excited O-16, and the energetic solar neutrons at 1 AMU Excess gamma ray and X-ray emissions were detected at relatively the same times during both flares in all energy bands, and were attributed to ion-induced emissions The timing of the peaks of electron and ion activity indicate that both electrons and ions are accelerated to their peak activity in under 5 sec

154 citations


Journal ArticleDOI
TL;DR: Results indicate that A. magnetotacticum is a microaerophilic denitrifier that is versatile in its nitrogen metabolism, concomitantly reducing NO(3) by assimilatory and dissimilatory means.
Abstract: Aquaspirillum magnetotacticum MS-1 grew microaerobically but not anaerobically with NO(3) or NH(4) as the sole nitrogen source. Nevertheless, cell yields varied directly with NO(3) concentration under microaerobic conditions. Products of NO(3) reduction included NH(4), N(2)O, NO, and N(2). NO(2) and NH(2)OH, each toxic to cells at 0.2 mM, were not detected as products of cells growing on NO(3). NO(3) reduction to NH(4) was completely repressed by the addition of 2 mM NH(4) to the growth medium, whereas NO(3) reduction to N(2)O or to N(2) was not. C(2)H(2) completely inhibited N(2)O reduction to N(2) by growing cells. These results indicate that A. magnetotacticum is a microaerophilic denitrifier that is versatile in its nitrogen metabolism, concomitantly reducing NO(3) by assimilatory and dissimilatory means. This bacterium appears to be the first described denitrifier with an absolute requirement for O(2). The process of NO(3) reduction appears well adapted for avoiding accumulation of several nitrogenous intermediates that are toxic to cells.

121 citations


Journal ArticleDOI
13 Jan 1983-Nature
TL;DR: Computational studies which examine the role of electrostatics in the formation of a putative reaction complex between flavodoxin and cytochrome c suggest that electrostatic interactions preorient the molecules before they make physical contact, facilitating theformation of an optimal reaction complex.
Abstract: Various studies have shown that reaction rates between revers-ibly binding electron transfer proteins depend strongly on solution ionic strength1–7. These observations suggest that inter-molecular electrostatic interactions are important in facilitating the formation of a productive reaction complex. A recently examined system involves the reduction of vertebrate cytochrome c by bacterial flavodoxin8,9. Although this is a non-physiological reaction, it proceeds with rates typical for natural partners and is similarly inhibited at high ionic strengths. Here we describe computational studies which examine the role of electrostatics in the formation of a putative reaction complex between flavodoxin and cytochrome c. The results suggest that electrostatic interactions preorient the molecules before they make physical contact, facilitating the formation of an optimal reaction complex.

Journal Article
TL;DR: Etude de l'anatomie interne et des structures ciliaires permettant l'identification des especes du sous ordre Urostylina permettants l'sidentification of the espece assignees precedemment a Keronopsis.
Abstract: Etude de l'anatomie interne et des structures ciliaires permettant l'identification des especes du sous ordre Urostylina. Description de Bakuella variabilis n.sp. Holosticha estuarii n.sp. et H. polystylata n.sp. On erige Pseudokeronopsis n.g. renfermant des especes assignees precedemment a Keronopsis

Journal ArticleDOI
TL;DR: This paper found that the tendency of acts of terrorism to incite further violence is more easily reversed in less democratic, poorer, and less well-educated societies, and that reversal of a terrorism epidemic is more likely under conditions facilitating repression rather than reform.
Abstract: There are important controversies over the dynamics of terrorism which have not yet been formally addressed in quantitative social research. We suggest a class of stochastic models for social contagion which may help to shed light on these controversies. Empirical estimates of model parameters were obtained from data on international terrorism in 16 countries over 1968–78. We find some evidence suggesting that the tendency of acts of terrorism to incite further violence is more easily reversed in less democratic, poorer, and less well-educated societies. This suggests that reversal of a terrorism ‘epidemic’ is more likely under conditions facilitating repression rather than reform, and that more open societies face particular difficulties in responding to terrorism effectively.

Journal ArticleDOI
01 Jul 1983-Tellus B
TL;DR: In this paper, a method for the simultaneous use of tracers for oceanic circulation studies is developed, based on a simple model for photosynthesis, bacterial decomposition and chemical dissolution.
Abstract: A method for the simultaneous use of tracers for oceanic circulation studies is developed. To permit the inclusion of tracers that are subject to biochemical transformation a simple model for photosynthesis, bacterial decomposition and chemical dissolution is formulated based on the use of Redfield ratios for the chemical compounds interaction. The finite difference analogue to the steady state tracer continuity equation, applied to the tracers chosen, leads to a set of simultaneous algebraic equations that in principle can be solved by matrix inversion methods. Two cases are considered: (1) The problem is indeterminate, which may be the case when too few tracers are available and/or some tracer equations are redundant. A solution is obtained by minimizing the transport vector; (2) The problem is incompatible, which may result from making use of many tracers. A solution is obtained by minimizing the errors in satisfying the tracer continuity equations. The method is applied to a 12-box model of the world oceans by considering the surface water, intermediate water, deep water and bottom water of the Arctic, Atlantic, Antarctic and Pacifichndian Oceans (with some simplification for the polar seas). Total dissolved inorganic carbon, alkalinity, phosphorus, oxygen and radiocarbon are used as tracers. A series of steady state solutions are presented and the uncertainties as dependant on box configuration and erroneous or nonrepresentative data are analysed. In the reference solution, circulation cells emerge where Antarctic surface water penetrates into intermediate levels of the two major oceans, from where it undergoes lifting and, at the surface, advection back towards the south. In the Atlantic, much of the penetrating water reaches as far north as to involve the Arctic deep water, which sinks and moves towards the deep Antarctic Ocean through the deep Atlantic. The total upwelling in the Antarctic Ocean is about 30 Sv. Turbulent exchange prevails between surface and intermediate waters in both major oceans with an average K, of about 1 cm 2 s -1 . Particular consideration is given to the transfer of carbon by computing the changes in total carbon and radiocarbon that are induced by fossil fuel combustion and nuclear bomb testing by using the steady state circulation and turbulent transfer deduced. It is concluded that better spatial resolution is required to determine the role of the ocean as a sink for injections of carbon and radiocarbon. DOI: 10.1111/j.1600-0889.1983.tb00025.x


Journal ArticleDOI
TL;DR: Equipment and techniques for sampling, preserving, packaging, shipping, and rearing forensically important insects should aid medicolegal professionals in data collection, allowing accurate determinations by entomological means.
Abstract: The insects and other invertebrates colonizing corpses as decomposition progresses can provide valuable information concerning the time and manner of death. Accurate determinations are possible, however, only when representative specimens are properly collected and preserved. The protocol developed by the authors describes equipment and techniques for sampling, preserving, packaging, shipping, and rearing forensically important insects. This information should aid medicolegal professionals in data collection, allowing accurate determinations by entomological means.

Journal ArticleDOI
TL;DR: RMR was independent of O2 max, or body fatness, but women had a significantly higher average RMR than men, and DIT was increased in proportion to the increase in aerobic capacity, and body fat decreased in males but not females.
Abstract: Resting metabolic rate (RMR), dietary thermogenesis (DIT), aerobic capacity ( $$\dot V$$ O2 max), and percent body fat were measured in a group of sixteen women and ten men. DIT was significantly positively correlated with aerobic capacity (r=0.658). Percent body fat was significantly negatively correlated with $$\dot V$$ O2 max (r=−0.727). RMR was independent of $$\dot V$$ O2 max, or body fatness, but women had a significantly higher average RMR than men. Three men and three women participated in an endurance training program which significantly increased $$\dot V$$ O2 max. DIT was increased in proportion to the increase in aerobic capacity (r s=0.924), RMR was unchanged, and body fat decreased in males but not females. The controversy surrounding “luxuskonsumption” may stem in part from not taking into account individual differences in aerobic capacity when measuring DIT.

Journal ArticleDOI
TL;DR: The Conflict Resolution Tactics between spouses, namely Reasoning, Verbal Aggression, and Violence, in Japan, India, and America were studied in this article, and information concerning family structures reported by 6...
Abstract: The Conflict Resolution Tactics between spouses, namely Reasoning, Verbal Aggression, and Violence, in Japan, India, and America were studied. Information concerning family structures reported by 6...

Journal ArticleDOI
TL;DR: The results are consistent with the hypothesis that predation contributed to the decline in the abundance and diversity of articulate brachiopods since the Mesozoic, and suggest that the restriction of recent populations to semi-cryptic rock wall and crevice habitats is, in part, controlled by disturbance.

Journal ArticleDOI
TL;DR: In this article, the authors describe several types of family mediation that have not been emphasized in the literature: contextual mediation, informal verbal mediation that occurs outside of the viewing situation, and mediation by families' organization in time and space.
Abstract: The potential of family members to serve as mediators of learning from television has received increasing amounts of attention in the literature. At the same time, the involvement of parents in their children's viewing has been found to be low. Using sample episodes from an ethnographic research study, this article describes several types of family mediation that have not been emphasized in the literature: contextual mediation, informal verbal mediation that occurs outside of the viewing situation, and mediation by families' organization in time and space. The authors suggest that ethnography can contribute to our understanding of the mediation of television by the family by documenting mediational influences that are unintentional, nonverbal, or occur at times other than during viewing.

Book ChapterDOI
01 Jan 1983
TL;DR: In this paper, the electron spectrum of cosmic ray electrons and positrons was analyzed with respect to its implications for the various energy loss processes occurring in interstellar space and also for its implications regarding the production of gamma-rays below ~ 100 MeV.
Abstract: We review recent measurements of cosmic ray electrons and positrons. In contrast to the earlier situation there now appears to be good agreement between different measurements of the electron spectrum at 10 GeV. These measurements are consistent with the previous so called “high” intensities. This new level of agreement permits the interstellar electron spectrum to be derived in a more precise way directly from the radio background measurements. This new electron spectrum is interpreted with regard to its implications for the various energy loss processes occurring in interstellar space and also for its implications regarding the production of gamma-rays below ~ 100 MeV. A primary electron spectrum after accleleration with an index of -2.3 ± 0.1 between a few MeV and several hundred GeV is consistent with the data.

Journal ArticleDOI
TL;DR: In this article, the causes of household water conservation were studied using combined survey and billing-record data on 431 households in a community that recently experienced a severe water shortage, and the largest...
Abstract: The causes of household water conservation are studied using combined survey and billing-record data on 431 households in a community that recently experienced a severe water shortage. The largest ...

Journal ArticleDOI
TL;DR: In this article, an area-averaged tidal bottom stress is made for four channel segments of the Great Bay Estuary, N.H. The analysis shows that while throughout the estuary the principal force balance is between the frictional stress and the pressure gradient forcing, RMS values of total bottom stress range from 2·67 to 10·38 Nm−2 and friction coefficients vary from 0·015 to 0·054.
Abstract: Estimates of area-averaged tidal bottom stress are made for four channel segments of the Great Bay Estuary, N.H. Current and sealevel measurements are used to estimate acceleration and pressure gradient terms in the equation of motion, while the equation of motion itself is used to infer the remaining stress term. Dynamic terms, bottom stress values, friction coefficients and energy dissipation rates are estimated for each site. The analysis shows that while throughout the estuary the principal force balance is between the frictional stress and the pressure gradient forcing, RMS values of total bottom stress range from 2·67 to 10·38 Nm−2 and friction coefficients vary from 0·015 to 0·054. Both stress and energy dissipation are largest in the seaward portion of the estuary with an order of magnitude decrease in dissipation at the most inland site. These distributions of stress and energy dissipation are consistent with cotidal charts of the principal semi-diurnal tidal constituent (M2) which indicate that the estuary is composed of a highly dissipative more progressive tidal wave regime seaward and a less dissipative standing wave regime landward.

Journal ArticleDOI
09 Sep 1983-Science
TL;DR: In the last 30 years the subject of asymmetric synthesis has grown from a little studied academic niche in organic chemistry to an intensely investigated field of commercial importance and heightened general interest.
Abstract: In the last 30 years the subject of asymmetric synthesis has grown from a little studied academic niche in organic chemistry to an intensely investigated field of commercial importance and heightened general interest. Impressive advances have been made in several areas, notably catalytic asymmetric homogeneous hydrogenation, catalytic asymmetric epoxidation of allyl alcohols and stereochemical control of carbon-carbon bond-forming reactions. Asymmetric synthesis must now be deliberately considered along with other available methods as a practical strategy for the synthesis of any chiral compound.

Journal ArticleDOI
TL;DR: Differences in stature and reproduction between the dwarf form and F. distichus ssp.

Journal ArticleDOI
TL;DR: Populations of both subspecies showed a distinct bimodal reproductive periodicity, with maxima in the spring and fall, and individuals were either reproductive in theSpring or fall but never in both seasons.

Journal ArticleDOI
TL;DR: Twenty-nine isolates (strains) were obtained from the Great Bay Estuary, New Hampshire, using a synthetic seawater medium with NaCl concentrations between 0.30 and 2.65 M and showed the following homogeneous characteristics: utilization of substrates, antibiotic response, acid production from sugars, colony morphology, catalase and oxidase production, lack of pigmentation and flourescence.
Abstract: Twenty-nine (29) isolates (strains) were obtained from the Great Bay Estuary, New Hampshire, using a synthetic seawater medium with NaCl concentrations between 0.30 and 2.65 M. All the strains were gram-negative; did not accumulate or hydrolyze poly-β-hydroxybutyrate; demonstrated ortho ring cleavage on aromatic compounds and showed the following homogeneous characteristics: utilization of substrates, antibiotic response, acid production from sugars, colony morphology, catalase and oxidase production, lack of pigmentation and flourescence; and had a mean guanine-plus-cytosine content of deoxyribonucleic acid composition of 63.2 ± 1.1 mol %. The strains demonstrated flagellated dimorphism; being motile by a singular polar flagellum at NaCl concentrations up to 0.8 M, and nonmotile and aflagellated at higher NaCl concentrations. A total of 150 biochemical, cultural, morphological, nutritional, and physiological traits were tested for the 29 strains and the type strain of six pseudomonad reference species. The 29 strains and reference strains were then compared with other reference and nonreference strains of the following genera: Aeromonas, Alcaligenes, Alteromonas, Arthrobacter, Flavobacterium, Pseudomonas, and Vibrio using 125 unit characters and employing numerical taxonomy by the Jaccard (SJ) coefficient and single linkage clustering method. The 29 strains were similar at the 95% level and clustered with several known Pseudomonas strains between the 70–75% similarity level (S) but clustered separately at S greater than 75% level. A type strain has been deposited with the American Type Culture Collection (ATCC 29686) and has been named Pseudomonas halodurans sp. nov.

Journal ArticleDOI
TL;DR: The biofilms growing in the first compartments of two rotating biological contactors used to treat municipal wastewater were examined by light and electron microscopy and found to contain a complex and varied microbial community that included filamentous and unicellular bacteria, protozoa, metazoa, and (possibly) bacteriophage.
Abstract: The biofilms growing in the first compartments of two rotating biological contactors used to treat municipal wastewater were examined by light and electron microscopy. The biofilms were found to contain a complex and varied microbial community that included filamentous and unicellular bacteria, protozoa, metazoa, and (possibly) bacteriophage. The predominant microorganism among these appeared to be a filamentous bacterium that was identical to Sphaerotilus in both morphological and ultrastructural characteristics. It was possible to isolate a Sphaerotilus -like bacterium from each contactor. Both the Sphaerotilus filaments and the wide variety of unicellular bacteria present tended to contain poly-β-hydroxybutyrate inclusions, a probable indication that these organisms were removing carbon from the wastewater and storing it. The microbial population of the biofilms appeared to be metabolically active, as evidenced by the presence of microcolonies and dividing cells. Images

Journal ArticleDOI
TL;DR: It is concluded that an endogenous, proctolin-like peptide is an inotropic modulator of the Limulus heart, acting directly on the muscle fibres and not affecting cardiac ganglion activity.
Abstract: 1. 1. Synthetic proctolin increases the force but not the rate of heart contractions of Limulus in a time- and dose-dependent manner. The threshold of this effect is 3 × 10−10M and the ED50 is approximately 10−8M. 2. 2. At concentrations up to 10−7 M, proctolin has no effect on the rhythmic electrical activity of the isolated cardiac ganglion, and it does not change the simple and compound postsynaptic potentials recorded at the cardiac neuromuscular junction. 3. 3. Proctolin acts directly on the cardiac muscle fibres. Electrically stimulated myocardia show a proctolin-induced increase in contraction amplitude with the same concentration dependence as the intact heart. 4. 4. A compound with an apparent molecular weight of 700–800 occurs in the Limulus nervous system, particularly in the cardiac ganglion. This compound resembles proctolin in being heat-stable, resistant to trypsin and chymotrypsin cleavage, and losing activity in a time-dependent manner in response to treatment with leucine aminopeptidase or pronase. This peptide induces spontaneous contractions and a contracture of the cockroach hindgut in a manner similar to proctolin. Moreover, the Limulus inotropic peptide, like proctolin, increases the force of contraction of the Limulus heart without affecting beat frequency. 5. 5. It is concluded that an endogenous, proctolin-like peptide is an inotropic modulator of the Limulus heart, acting directly on the muscle fibres and not affecting cardiac ganglion activity.

Journal ArticleDOI
TL;DR: These experiments demonstrate that classical conditioning procedures are sufficient to establish conditioned reflexes in which stimuli (which were previously neutral with respect to the immune system) enhance antibody production.
Abstract: In Experiments 1 and 2, rats were exposed to a classical conditioning procedure in which saccharin and lithium chloride (LiCl) were paired with an injection of antigen. Relative to control groups, the conditioned animals that received additional saccharin and LiC1 presentations showed significantly higher antibody levels. These experiments demonstrate that classical conditioning procedures are sufficient to establish conditioned reflexes in which stimuli (which were previously neutral with respect to the immune system) enhance antibody production.