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Simulation models and games are being used more and more as a teaching strategy in the instructional process. A wide variety of simulations are currently available for use at all grade levels from pre-school to post-graduate work. They have been used to teach both content and skills, and have proven to be an effective aid in learning for all ability levels. The term “simulation” has been defined by many people in a variety of fields. Some of those relevant to education include

Clonidine, an alpha-2-adrenergic agonist, suppresses signs of opiate withdrawal in animals and in man. Electrical or chemical stimulation of the nucleus locus coeruleus (LC) increases noradrenergic activity and brain concentration of the noradrenergic metabolite MHPG, and produces many signs of opiate withdrawal. Thus, clonidine's ability to attenuate withdrawal might be due to the reduction of noradrenergic neuronal activity originating in the LC, but additional alpha-2-adrenergic receptors throughout the body and other mechanisms may also play a role. The present study explored the neuroanatomical and pharmacological selectivity of alpha-2-adrenergic receptors of the LC in the anti-withdrawal action of clonidine. Experiment 1 tested the hypothesis that behavioral and biochemical measures of naloxone-precipitated withdrawal from morphine would be blocked by infusions of clonidine (0.6 or 2.4 micrograms/microliters) into the LC. Significant reductions were observed in the occurrence of diarrhea, ptosis, weight loss and wet-dog shakes. Clonidine also reversed the naloxone-precipitated increase in hippocampus MHPG concentration. In experiment 2 subjects received an LC infusion or IP injection of a non-lipophilic alpha-2-agonist (ST-91), which does not penetrate the blood-brain barrier, or of clonidine into the dorsal parabrachial nucleus (DPB) to test the selectivity of the effects of clonidine infusions into the LC. ST-91 infusions into the LC reduced several of the observed withdrawal signs and increased others (e.g., jumping). Although peripheral injections of ST-91 attenuated some of the checked signs associated with naloxone-precipitated withdrawal, the frequency of wet-dog shakes was not reduced. ST-91 infusions into the LC, but not systemic ST-91 administration, prevented the withdrawal-induced increase in hippocampus MHPG concentration. Clonidine infused lateral to the LC into the DPB did not significantly attenuate withdrawal or reduce hippocampus MHPG levels. These results provide behavioral and biochemical evidence to support the suggestion that clonidine significantly attenuates naloxone-precipitated withdrawal through an interaction with noradrenergic neurons located in the vicinity of the LC.

Stimulant drugs have been shown to enhance the control over behaviour exerted by stimuli previously correlated with primary reinforcers, termed conditioned reinforcers (CR). Experiment 1 examined the possible neuroanatomical specificity of the enhancement of conditioned reinforcement following intracerebral injections of d-amphetamine. Thirsty rats were trained to associate a light with water. In the test phase, water was no longer presented but the light (CR) was intermittently produced by responding on one of two novel levers. Rats with bilateral guide cannulae aimed at the nucleus accumbens, posterior caudate nucleus, or medio-dorsal nucleus of the thalamus received four counterbalanced microinfusions of d-amphetamine (10, 20, 30 micrograms/2 microliters) or vehicle (control) over 4 test days. There was a dose-dependent selective increase in responding on the lever that produced the light (CR) with intra-accumbens d-amphetamine infusions. Quantitatively similar, but much more variable effects were found with intra-caudate infusions and no effects following intra-thalamic d-amphetamine. Experiment 2 provided evidence that the enhanced control over responding by a CR with intra-accumbens d-amphetamine is behaviourally specific. Three groups of rats received a compound tone--plus--light stimulus that was positively, negatively or randomly correlated with water during training. Intra-accumbens d-amphetamine produced selective increases in responding only if the contingent stimulus had been positively correlated. The results suggest that the nucleus accumbens may play an important role in d-amphetamine's enhanced control over behaviour exerted by conditioned reinforcers.

Dry weight and N, P, K, Ca, and Mg concentrations were monitored in the litter fall and forest floor of a loblolly pine (Pinustaeda) plantation in north Louisiana for 2 years. Dry weights of both litter fall and forest floor were statistically stable during the sampling period, possibly indicating steady-state conditions. A comparison of litter fall with forest floor weights indicated rapid decomposition (floor turnover = 1.5 years) relative to that of other loblolly pine systems.

OBJECTIVE--To assess whether an organised programme of prevention including the use of a health promotion nurse noticeably improved recording and follow up of cardiovascular risk factors and cervical smears in a general practice that had access to computerised cell and recall. DESIGN--Randomised controlled trial. SETTING--General practice in inner London. PATIENTS--All 3206 men and women aged 30-64 registered with the practice. INTERVENTION--The intervention group had their risk factors ascertained and followed up by the health promotion nurse and the general practitioner, whereas those in the control group were managed by the general practitioner alone. END POINT--Recording and follow up of blood pressure and cervical smears after three years. Recording of smoking, family history of ischaemic heart disease, and serum cholesterol concentrations were also examined. MEASUREMENTS and MAIN RESULTS--When the trial was stopped after two years the measurements of blood pressure in the preceding five years were 93% (1511/1620) v 73% (1160/1586) (95% confidence interval for difference 17.5 to 22.7%) for intervention and control groups respectively. For patients with hypertension the figures were 97% (104/107) v 69% (80/116) (18.2 to 38.2%). For women the proportion who had had a cervical smear in the preceding three years were 76% (606/799) v 49% (392/806) (22.5 to 31.9%). Recording of smoking, family history of ischaemic heart disease, and serum cholesterol concentrations was also higher in the intervention group compared with the control group. CONCLUSION--An organised programme, which includes a nurse with specific responsibility for adult prevention, is likely to make an important contribution to recording of risk factors and follow up of those patients with known risks.

Frozen foods do not have an indefinite storage life, and hence it is necessary to monitor their quality over time and at different storage temperatures. A number of previous studies have investigated this, but recent changes in processing and packaging techniques have rendered these out-dated. The objective of this study was to investigate the sensory quality of frozen Brussels sprouts at different temperature-time combinations. Descriptive profiling in combination with principal component analysis provided an informative picture of the main sensory attributes, which changed with time and storage temperature. This information could be used by the industry to evaluate the shelf life and acceptability of its products.

The Myers-Briggs Type Indicator scores of 170 certified psychodramatists were collected. As anticipated, self-selection was readily apparent in the group as 87% were intuitive rather than sensing types. Psychodramatists are most likely to be intuitive feelers, and extraverted intuitive feeling perceivers represent 29% of all certified professionals. In general there were no major differences in psychological types between psychodramatists and samples from their original academic training (psychology, social work, etc.). In comparing psychodramatists with other psychotherapeutic orientations, psychodramatists were most like experiential psychotherapists and most different from psychoanalytic therapists. As compared to Jacoby's scale of innovative versus conservative types, 87% of the psychodramatists are innovative. That spontaneity and creativity are regarded as essential to psychodrama is suggested by both the preponderance of innovative types among professionally certified psychodramatists and the systematic exclusion of most conservative types. Studies of other certified therapists would provide a base for further comparison of psychological types between psychotherapeutic orientations.

The kinetic parameters of in vivo ethylene metabolism by seedlings of Pisum sativum L. cv. Alaska have been determined. The oxidation of ethylene to CO2, (Ox) and the incorporation of ethylene into the tissue (TI) were both shown to display Michaelis-Menten kinetics (Km Ox = 0.9 × 10−6 M liquid phase, Vmax Ox = 2.4 × 10−10 moles g− dry mass h−1 Km TI = 1.6 × 10−6 M liquid phase, Vmax TI = 4.5 × 10−10 moles g−1 dry mass h−1). Propylene competitively inhibited both Ox (Ki = 7.0 × 10−6 M) and TI (Ki = 3.7 × 10−7 M). A system comparable to Ox was absent from imbibed cotyledons of Vicia faba L. cv. Aquadulce even at saturating concentrations of ethylene similar to those used in kinetic analysis on Pisum. Silver ions were shown to inhibit TI but promoted Ox, while carbon dioxide inhibited Ox but promoted TI. Kinetic data on both these effects are presented. Data on the effect of a range of concentrations of CO2 on TI and Ox are also presented.

Thermal regulation is a key ecosystem service provided by urban plants. In addition to summer cooling, plants can insulate buildings against heat loss in winter. Research was conducted over two winters using replicated small-scale physical models to simulate heat loss from a built structure and to investigate the insulation properties of plants during cold weather. Brick cuboids were constructed around a water tank maintained at 16 °C and energy use monitored. Covering cuboids with ivy (Hedera helix) reduced mean energy consumption by 21% compared to bare cuboids during the first winter (means of 4.3 and 5.4 kWh per week, respectively). During the second winter, when foliage was more extensive a 37% mean saving was achieved (3.7 compared to 5.9 kWh per week). The presence of Hedera enhanced brick temperatures significantly compared to bare walls. Temperature differences were affected by weather parameters, aspect, diurnal time and canopy density. Largest savings in energy due to vegetation were associated with more extreme weather, such as cold temperatures, strong wind or rain. Under such scenarios green facades could increase energy efficiency by 40–50% and enhance wall surface temperatures by 3 °C. These empirical studies with replicated treatments augment previous research based on urban modelling and data from non-replicated individual buildings in situ. They indicate that planting design requires more attention to ensure the heat saving aspects associated with green facades and shelter belts are optimised. These aspects are discussed within the context of wider urban ecosystem services provided by vegetation, and implications for climate change mitigation.

The biosynthetic basis for the high rates of ethylene production by the apical region of etiolated pea (Pisum sativum L.) seedlings was investigated. The ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) was quantified in extracts of various regions of seedlings by measuring isotopic dilution of a (2)H-labelled internal standard using selected-ion-monitoring gas chromatography/mass spectrometry. The ACC levels in the apical hook and leaves were much higher than in the expanded internodes of the epicotyl. The capacity of excised tissue sections to convert exogenous ACC to ethylene was also much greater in the apical region, reflecting the distribution of soluble protein in the epicotyl.

The occurrence of endogenous indole-3-acetic acid and ethylene in bryophyte tissue was tentatively demonstrated using gas chromatography, high performance liquid chromatography, and double-standard isotope dilution techniques. Rapidly elongating stalks (or setae) of Pellia epiphylla (L.) Corda sporophytes contain approximately 2.5 to 2.9 micrograms per gram fresh weight of putative free IAA. Ethylene released by setae increases during growth from 0.027 to 0.035 nanoliter per seta per hour. Application of 5 microliters per liter ethylene inhibits auxin-stimulated elongation growth of this tissue, a result which suggests that both endogenously produced compounds act in tandem as natural growth modulators.

SUMMARY 1. Inactive renin has been studied extensively in human plasma, but in animal plasma its accurate quantification has proved more difficult, due partly to higher activity of plasma protease inhibitors. Such activity in human plasma can be conveniently destroyed by a metalloprotease in Bitis arietans venom, with concommitant release of endogenous enzyme activities, such as plasma kallikrein, that then activate inactive renin. It was therefore of interest to look for inactive renin in rat and rabbit plasma using this approach, so providing, in addition, a comparison for the disparate data of other groups who have used trypsin or acid for activation. 2. In both rat and rabbit plasma the proportion of inactive renin was 62% of total renin, whereas human plasma contained more inactive renin and a higher proportion, 82%. A higher concentration of venom was required for rat (33 ug venom/ml plasma) and rabbit (4 μg/ml) than needed for activation, at a similar rate, in human plasma (1 μg/ml). 3. When applied to studies of rats made hypertensive and hyper-reninaemic by aortic ligation for 5 days, higher total (active + inactive) renin was observed. The proportion of inactive renin, as a percentage of total renin in plasma collected at this time, was, however, found to diminish significantly. 4. In conclusion, puff adder venom activates inactive renin in rat and rabbit plasma and can be used to study physiological changes in inactive renin in such animal plasma.

Summary This study compares the regulation of IGF-II receptors in three rat hepatoma lines, HTC, H-35 and 5123tc, and primary rat hepatocytes. In all cell types [ 125 I]IGF-II bound solely to a species of approximately 250 kDa. Cell surface IGF-II receptors in hepatoma cells had slightly lower affinities (1–2 liter/nmol) than in hepatocytes (4 liter/nmol), but slightly higher IGF-I cross-reactivity (2–4% compared to 1% in hepatocytes). In confluent cultures, the three hepatoma lines expressed 5- to 15-fold more cell-surface receptors per cell than hepatocytes. However, while hepatocyte receptors showed marked inverse density-dependence, increasing over 6-fold between dense (3×10 5 cells/3.8 cm 2 ) and sparse (0.16×10 5 cells/3.8 cm 2 ) cultures, receptors in all hepatoma lines remained at a constant high level regardless of culture density. These distinct regulatory patterns resemble those described for growth-related functions in hepatocytes and hepatoma cells, and are thus consistent with a role for IGF-II receptors in liver cell proliferation.

Intra-accumbens d-amphetamine enhances responding for reward-related stimuli (conditioned reinforcers, CRs), whereas intra-caudate d-amphetamine has only weak and variable effects (Taylor and Robbins 1984). The present experiment further examined the involvement of the nucleus accumbens and the role of dopamine (DA) in this effect. Thirsty rats were trained to associate a flash of a light and movement of a dipper (CR) with water. After implantation of permanent guide cannulae aimed at the nucleus accumbens, they were assigned to one of four groups, receiving either bilateral 6-OHDA (4 mg/ml free base in 2 μ1 0.1% ascorbic acid/0.9% saline) or sham (vehicle) infusions into the nucleus accumbens or the caudate nucleus. In the test phase, two novel levers were available. Responding on one lever (CR lever) produced the light and dipper stimuli without water presentation, whereas responding on the other (NCR lever) had no effect. All four groups received four counterbalanced intra-accumbens infusions of d-amphetamine (3, 10, 20 μg/2 μl) or vehicle. On the 5th test day, subjects were pretreated subcutaneously with apomorphine (0.1 mg/kg). Intra-accumbens d-amphetamine in both sham-lesioned groups produced a dose-dependent increase in responding on the CR lever, but no significant change on the NCR lever. No selective increases in responding on either lever were found in animals with 6-OHDA-induced depletion of DA (>80%) in the nucleus accumbens following intra-accumbens d-amphetamine; however, in subjects with DA depletion of the posterior caudate nucleus (>80%), increases in responding on the CR lever were observed to be similar in magnitude to those of both the sham-lesioned groups. Following systemic administration of apomorphine, only rats in the nucleus-accumbens-lesioned group continued to respond, preferring the CR lever, thus suggesting the involvement of DA receptors in these effects. These results indicate that enhanced responding for CR following administration of psychomotor stimulant drugs is critically dependent on dopaminergic activation of the nucleus accumbens, rather than the caudate nucleus.

Stimuli with formerly motivationally neutral properties gain incentive properties from their predictive association with primary reinforcement, and are termed conditioned reinforcers. Infusions of the indirect dopamine (DA) agonist d-amphetamine into the ventral striatum selectively enhanced responding for a light that was positively correlated with water. These selective stimulatory effects were blocked by 6-OHDA lesions of the ventral, but not dorsal striatum, and resembled those produced by DA itself when infused into the ventral striatum. However, the choice of the lever producing the conditioned reinforcer was not affected by ventral striatal DA depletion. This choice was, however, attenuated by excitotoxic lesions of the basolateral nucleus of the amygdala, suggesting an interaction between this structure and DA-dependent processes of the ventral striatum in the processes by which reward-related stimuli come to affect action. Parallel findings were obtained using a second order schedule of sexual reinforcement. Other observations indicated that the amygdala lesion did not impair the discriminative property of the reward-related stimuli, or affect primary motivation. Experiments using explicit conditional visuo-spatial discrimination tasks suggest that similar discriminative properties are preserved following DA depletion from the ventral, but not the dorsal, striatum. These results possibly represent a dissociation between stimulus-response (or habit) and stimulus-reward associative mechanisms, modulated respectively by the dorsal and ventral striatum.

The natural shedding of leaves takes place at predictable locations on a plant. It is the culmination of a spectrum of physiological and biochemical events which are restricted to precise cellular locations known as abscission zones (Sexton and Roberts, 1982). It is possible to induce leaf abscission prematurely by exposure of the tissue to the plant growth regulator ethylene (Abeles, 1973). Ethylene-induced shedding shares many features in common with the natural process, and there is good reason to believe that this gaseous regulator may influence the timing of leaf fall in vivo (Morgan, 1986).

THE prediction of immunologic tolerance by Burnett and Fenner1 suggested that tolerance to the Rh antigen might be induced in Rh-negative girls born of Rh-positive mothers.2 Immunologic tolerance was considered possible because maternal red cells cross the placenta to the fetus in at least some pregnancies.3 4 5 6 A contrary opinion held that the few authenticated cases of hemolytic disease, in first-born infants of mothers who had received no known stimulus, might be due to sensitization acquired by the mother in utero.7 , 8 This study was undertaken to determine whether Rh-positive mothers induce immunologic tolerance or primary sensitization in their Rh-negative daughters . . .

In two deep wells in Wyoming three types of pore-space reduction occur. These are simple pore filling, solid flow, and solution and redeposition or removal of the dissolved material. Five sands, ranging in depth from 2,885 to 8,343 feet, and sections of randomly packed sand grains were studied. Sand-grain contacts, as they appear in the plane of a random thin section, are classified. The number of contacts per grain and types of contacts due to pressure increase with depth, and each type of contact has its individual trend with increasing depth. Development of tension cracks and crushing of fragile grains are other features due to pressure. Some cementation and replacement occur, but no depth relationship can be established.

CDeT6-19 is an ABA-regulated gene which has been isolated from Craterostigma plantagineum. The CDeT6-19 gene promoter has been fused to the beta-glucuronidase reporter gene (GUS) and used to stably transform Arabidopsis thaliana and Nicotiana tabacum. This construct has been shown to be expressed in stomatal guard cells and often in the adjacent epidermal cells of both species in response to both exogenous ABA and drought stress. These results indicate that the stomatal guard cell is competent to relay an ABA signal to the nucleus. In contrast GUS expression directed by the promoter from a predominantly seed-specific, ABA-regulated gene, Em, or the promoter from the ABA-regulated CDeT27-45 gene is not detectable in the epidermal or guard cells of tobacco or Arabidopsis in response to ABA. The fact that not all ABA-regulated gene promoters are active in stomatal guard cells suggests that effective transduction of the signal is dependent upon particular regions within the gene promoter or that guard cells lack all or part of the specific transduction apparatus required to couple the ABA signal to these promoters. This suggests that there are multiple ABA stimulus response coupling pathways. The identification of a regulatory sequence from an ABA-induced gene which is expressed in stomatal guard cells creates the possibility of examining the role of Ca2+ and other second messengers in ABA-induced gene expression.

During the course of development a spectrum of organs are shed from a plant [1]. Although the cellular and molecular mechanisms by which the abscission process is brought about have yet to be ascertained, the final event is the dissolution of the cell wall at the site where shedding takes place. A major difficulty encountered when studying abscission is that only a few rows of cells may undergo separation. In bean, there is convincing evidence that only one or two rows of cells may contribute to the loss of the primary leaf [2] while in tomato flowers there may be 5-10 rows of cells involved in the process [3]. In an attempt to examine the molecular changes which lead to abscission we have chosen to study the shedding of leaflets in Sambucus nigra [4,5,6]. This is a well characterised system and as the leaflet abscission zone is a composite of three sites where cell separation takes place, as many as 50 rows of cells may be involved in the process [7]. Moreover, leaflet abscission can be induced in approximately 24 hours by exposure to ethylene (10 μ1 1-1) and the use of explants leads to a close degree of synchronisation of the process [5].

In this paper, we evaluate the use of an electronic nose (EN) containing 13 conducting polymer gas sensors to discriminate between patterns of volatile organic compounds (VOCs) emitted by plants. The VOC patterns examined were produced by tomato, cucumber and pepper plants under both healthy and infected or infested conditions. Leaves from the plants were subjected to mechanical damage or pest and disease attacks (i.e. spider mites infested or mildew infected) and others were judged against undamaged healthy leaves. Support vector machines (SVMs) with linear, polynomial and Gaussian radial basis function (RBF) kernels were used to process and classify the raw data collected. The SVM illustrated an ability to discriminate between different VOC patterns and hence was able to classify correctly the infected leaves using the EN data. The results indicate that the array of 13 EN gas sensors can discriminate among VOC patterns from undamaged and artificially damaged leaves of the three plant species. This study demonstrates the potential application of such an EN technology coupled with suitable pattern recognition and signal processing methods to be used as a real time pest and disease detection system in the greenhouse environment.

Asynchronous Chinese hamster ovary cells were microinjected with glutathione disulfide (GSSG). Successfully injected cells were scored by coinjecting FITC-dextran with GSSG, followed by fluorescent microscopy. After microinjection, cells were incubated for 2.5 h at 37°C to permit thermotolerance development and then heated at 45°C for 40 min. Cellular heat sensitivity was quantitated by counting the number of grains per cell after labeling heated cells with tritiated amino acids and processing for autoradiography. The data show that microinjection of GSSG induced thermotolerance which increased the number of grains per cell up to 500% of controls. Cells that were exposed to similar concentrations of GSSG in culture medium without microinjection or microinjected without GSSG did not develop thermotolerance.

International audience; The 15 original essays in this volume represent only a few of the paths that Glyn Burgess’s research career has taken: lays, by Marie de France and unknown authors; manuscript collections of lays and fabliaux; episodic narratives, from ancestral/​outlaw romance and Norman vernacular historiography; transformations of the Brendan legend; and authorial voice in religious texts, including Wace’s. The diversity of content and approaches has created a volume which will serve both as a fitting tribute to Burgess’s continuing influence and expertise, as well as a contribution to the growing theoretical and applied work in the area of the short narrative, which the authors extend to a very broad range of works, from fabliau to hagiography, from history to myth. This breadth of interest, within a close and analytical focus on short narrative, make this an important, indeed unique, collection.