Favouritism in the motor system: social interaction modulates action simulation

The ability to anticipate others'' actions is crucial for social interaction. It has been shown that this ability relies on motor areas of the human brain that are not only active during action execution and action observation, but also during anticipation of another person''s action. Recording electroencephalograms during a triadic social interaction, we assessed whether activation of motor areas pertaining to the human mirror-neuron system prior to action observation depends on the social relationship between the actor and the observer. Anticipatory motor activation was stronger when participants expected an interaction partner to perform a particular action than when they anticipated that the same action would be performed by a third person they did not interact with. These results demonstrate that social interaction modulates action simulation.     

Interaction of polymorphonuclear leukocytes, bradykinin and carragenin. Transference reaction in the rat

1. Injected in the paw of the rat, polymorphonuclear leucocytes do not increase the oedematogen action of bradykinin, but increase the action of lambda carrageenan. 2. This potentiation of carrageenan action is not modified when PG biosynthesis in leucocytes is inhibited by indomethacin or aspirin. It does not appear in rats previously treated by indomethacin or aspirin. 3. Our results suggest that rat polymorphonuclear leucocytes increase the inflammatory reaction, when they are stimulated by carrageenan, by the release of a phospholipase A2 activity which induces PG biosynthesis in rat paw tissues.     

The influence of high hydrostatic pressure on cocaine and veratrine action in a vertebrate nerve

The application of high hydrostatic pressure to toad sciatic nerve causes a gain in sodium and a loss of potassium which are not affected by cocaine. However, cocaine action is enhanced by high pressure when counteracting veratrine depolarization and when blocking the action potential. Various effects of elevated pressure on the after-potentials are presented and the role of ions in these processes is discussed.     

Impaired motor facilitation during action observation in individuals with autism spectrum disorder

It has been suggested that social impairments observed in individuals with autism spectrum disorder (ASD) can be partly explained by an abnormal mirror neuron system (MNS) 1., 2.. Studies on monkeys have shown that mirror neurons are cells in premotor area F5 that discharge when a monkey executes or sees a specific action or when it hears the corresponding action-related sound 3., 4., 5.. Evidence for the presence of a MNS in humans comes in part from studies using transcranial magnetic stimulation (TMS), where a change in the amplitude of the TMS-induced motor-evoked potentials (MEPs) during action observation has been demonstrated 6., 7., 8., 9.. These data suggest that actions are understood when the representation of that action is mapped onto the observer's own motor structures [10]. To determine if the neural mechanism matching action observation and execution is anomalous in individuals with ASD, TMS was applied over the primary motor cortex (M1) during observation of intransitive, meaningless finger movements. We show that overall modulation of M1 excitability during action observation is significantly lower in individuals with ASD compared with matched controls. In addition, we find that basic motor cortex abnormalities do not underlie this impairment.     

Calcium dependent action potentials in skeletal muscle fibres of a beetle larva, Xylotrupes dichotomus

The ionic requirement for generating action potentials in ventral longitudinal muscle fibers dissected from beetle larvae was examined by conventional electrophysiological techniques. Muscle fibers that generated only graded responses in physiological saline were able to generate an all-or-none action potential when the potassium permeability of the membrane was inhibited by tetraethylammonium⁺ added to the saline. The peak of the action potential thus elicited was intimately related to the external Ca⁺⁺ concentration. The action potential was blocked by Co⁺⁺ which is known as a competitive inhibitor of Ca-spikes. Neither tetrodotoxin (3 μM) nor a Na-free condition effectively blocked the generation of the action potential. Mg⁺⁺ induced a shift in the peak of the action potential; this was, however, due to the stabilizing action of Mg⁺⁺ but not due to the penetration of Mg⁺⁺ through the muscle membrane. No action potential was elicited in the muscle fiber when immersed in a Ca-free, EGTA saline even when a high concentration of either Mg⁺⁺, Na⁺, or tetraethylammonium⁺ was present. The action potential of the larval muscle fiber was thus concluded to be a Ca-spike, through the channel of which Na⁺ or Mg⁺⁺ did not penetrate.     

Peptide YY reduces effects of sympathetic nerves and neuropeptide Y on cardiac vagal action.

In anesthetized dogs intravenous injection of neuropeptide Y (NPY) or stimulation of the cardiac sympathetic nerve is followed by a period of attenuation of vagal action at the heart lasting from many minutes to over an hour. Peptide YY (PYY), a related peptide (but one not reported to occur in the heart or its autonomic innervation), also inhibits cardiac vagal action but is more powerful and has a longer duration action. In 5 of 9 dogs, cardiac sympathetic nerve stimulation inhibited vagal action on the heart in control conditions, but relieved preexisting inhibition when repeated in the presence of PYY. In 3 dogs, exogenous NPY inhibited cardiac vagal action in control conditions, but failed to augment preexisting inhibition in the presence of PYY. An explanation offered for these results is that when PYY is occupying receptors on vagal nerve terminals, nerve-released NPY or exogenous NPY is either unable to produce an effect, because it cannot gain access to the receptors, or displaces PYY from at least some receptors and, being less powerful than PYY in its inhibitory action, lessens the preexisting vagal attenuation. The results reported are consistent with the proposal that the factor released from the sympathetic nerves following their stimulation and which is responsible for cardiac vagal inhibition is NPY.     

The mode of action of pyrethnxm on the cockroach, Periplaneta americana L

Pyrethrin, the active principle of pyrethrum powder, is insoluble in water but is soluble in, the body fluid of the cockroach. It has a selective action on nerve ganglia, and the destruction of their cells is responsible for the death of the insect. Whereas pyrethrum, when used -either in the powdered form or in a fluid state mixed with kerosene and introduced directly into the body cavity reaches the ganglion with the circulation, its mode of action when it acts through the spiracles is different. Kerosene-pyrethrum mixture when introduced into the tracheal trunks through the spiracles is quickly diffused into the haemocoele. When the dry powder is inserted into the trachea, its mode of action is analogous to a fluid preparation. As the conversion of pyrethrum from a dry into a fluid state is alone possible in the interior of the trachea, the natural conclusion is that a fluid analogous to the body fluid is present in the same situation. As soon as the pyrethrin is dissolved, it is quickly diffused into the haemocoele and thus reaches the nearest ganglion.     

土壤水分和氮磷营养对小麦根系生理特性的调节作用

研究结果表明：在土壤相对含水量(SRWC)为40％～70％范围内,随着水分亏缺加重,小麦根系生长受到限制,根系比表面积(RA)、根水势(RΨw)明显降低,根呼吸(RP)作用加强,根长(RL)变短,根系干物重(RDW)减少;随着土壤水分趋于良好,RΨw明显增加,Rp作用显著降低,SRWC在54％～57％时RA最高,RDW在SRWC为55％～62％之间时最大,而SRWC在55％上下时RL达最长,表明土壤水分趋于轻度干旱有利根系下扎和RA的提高,土壤水分趋于良好有利于根量增长。氮磷营养对根系生理特性具有明显作用。磷营养可显著提高RA,RΨw,RL,RDW,降低Rp,在较为严重干旱条件下,磷对RA,RP,RΨw,RL的调节效果更好。氮素营养对小麦根系生理特性的调节效果与磷相比具有明显的差别。土壤严重干旱,氮引起RΨw的明显下降,为负效应;轻度干旱氮对RΨw无明显作用;在水分良好条件下,氮对RΨw具有显著的正向调节效果。氮营养可使Rp作用明显加强。随着SRWC的提高,增施氮肥可导致RDW的显著增加。小麦RL对氮的反应不敏感。磷除作为一种营养物质促进作物根系生长发育外,在水分胁迫条件下,磷可明显改善植株体内的水分关系,增强对干旱缺水环境的适应能力,提高作物抗旱性。     

Uniform and Complementary Social Interaction: Distinct Pathways to Solidarity

We examine how different forms of co-action give rise to feelings of solidarity. We propose that (a) coordinated action elicits a sense of solidarity, and (b) the process through which such solidarity emerges differs for different forms of co-action. We suggest that whether solidarity within groups emerges from uniform action (e.g. synchronizing, as when people speak in unison) or from more complementary forms of action (e.g. alternating, when speaking in turns) has important consequences for the emergent position of individuals within the group. Uniform action relies on commonality, leaving little scope for individuality. In complementary action each individual makes a distinctive contribution to the group, thereby increasing a sense of personal value to the group, which should contribute to the emergence of solidarity. The predictions receive support from five studies, in which we study groups in laboratory and field settings. Results show that both complementary and uniform co-action increase a sense of solidarity compared to control conditions. However, in the complementary action condition, but not in the uniform action (or synchrony) condition, the effect on feelings of solidarity is mediated by a sense of personal value to the group.     

Control charts for improved decisions in environmental management: a case study of catchment water supply in south‐west Western Australia

Environmental monitoring is becoming increasingly sophisticated with the widespread adoption of data loggers, sensor arrays and remote sensing, leading to larger scale, higher resolution and superior quality data. However, interpreting monitoring data and deciding when and how to apply environmental management remains a subjective and underdeveloped area of research. Control charts, developed in industrial settings to identify when manufacturing processes were beyond the acceptable bounds of production quality, represent one solution. Despite their potential utility, control charts have rarely been adopted in environmental monitoring. In theory, they are able to identify undesirable trends early and provide transparent and broadly consensual criteria for defining when management action should take place, that is action is triggered when parameter values are observed beyond the agreed control limits of the process. Once triggered, a predetermined management action is implemented. Possible actions are many and varied, and range from investigation and increased monitoring to intervention in the system. Here, the utility of control charts in monitoring water supply in south‐western Australia from 1911 to 2010 is examined, and their ability to provide an early, transparent and easily understandable means of triggering management action is assessed. Two control chart types are applied: the X‐bar chart and the CUSUM chart. X‐bar charts varied widely in their ability to trigger action and were insensitive to many traditional threshold criteria (of which there are many to choose from). In contrast, standard CUSUM charts are specifically designed to detect subtler shifts away from a mean trend and hence provided a more consistent warning of the decline in water supply. While managers were aware of the decline in water supply from an early stage, we believe that control charts could have clearly communicated this earlier, enabling consensus among decision makers to be reached more rapidly.     

Osmotic dependence of the lysophosphatidylcholine lytic action on liposomes in the gel state

Multilamellar liposomes of dimyristoylphosphatidylcholine are susceptible to lytic action of lysophosphatidylcholine at the gel state, an effect which is not observed when liposomes are in the liquid crystalline state. The lytic action has been found to be enhanced when liposomes are dispersed in hypertonic solutions. On the contrary, hypotonic solutions decreased the effectiveness of the lysolipid. Shrunken liposomes present surface changes as detected by merocyanine 540 and 1-anilinonaphthalene-8-sulfonic acid which can be ascribed to the spontaneous curvature promoted by shrinkage.     

Environmental governance for urgent and uncertain problems

Environmental governance aims to support positive ecological outcomes by establishing effective joint decision-making processes. Yet, complex environmental problems, such as invasive species management, often require urgent action under conditions of uncertainty. Establishing clear and workable environmental governance arrangements in these circumstances can be challenging, or even overlooked completely, in the rush to take action. We undertook an exploratory study, involving semi-structured interviews with 15 policy-makers and scientists, to examine the proposition that some aspects of environmental governance can be more important than others when urgent action is required under conditions of uncertainty. We analysed qualitative data regarding the major decisions points of a case study of invasive species management in Tasmania, Australia. We identified specific elements of governance that, when used under conditions of urgency and uncertainty, can: (a) undermine the ability to establish effective governance arrangements over the longer-term; or alternatively (b) lay the foundation for inclusive and adaptable governance arrangements. Aspects of environmental governance that can be more important than others when responding to urgent and uncertain problems relate to: assessing context; establishing a temporary task-force and setting goals; co-producing knowledge with stakeholders; engaging early; and clarifying and communicating responsibilities and governance arrangements. From our findings, we pose questions for policy-makers and practitioners to ask when responding to urgent problems, creating an opportunity to establish basic governance arrangements even when immediate action is required. These basic arrangements can have the capacity to evolve and respond to increasing levels of certainty, complexity and inclusion.     

THE SYSTEMIC INSECTICIDAL ACTION OF SODIUM FLUOROACETATE AND OF THREE PHOSPHORUS COMPOUNDS ON THE EGGS AND LARVAE OF PIERIS BRASSICAE L.

Four compounds, bis dimethylaminophosphonous anhydride ( anhydride ), bis (dimethylamino)fluorophosphine oxide ( oxide ), diethyl paranitrophenyl phosphate ( E 600) and sodium fluoroacetate ( acetate ), previously shown to have systemic insecticidal activity against aphids, have now been tested against the eggs and larvae of Pieris brassicae L.
The anhydride proved to have very little toxic action on Pieris , but the other three compounds showed both contact toxicity and systemic insecticidal action when taken up by the roots of cabbage plants from solution and from soil. The acetate, but more especially the E600, also showed systemic action following application to the leaves.
In all cases the order of decreasing toxicity was E600 > acetate > oxide > anhydride. E600 is the only compound which is outstandingly toxic to Pieris eggs and larvae. It has the added interest that when watered on to the roots of cabbage plants it kills larvae in egg batches on the leaves. Death takes place at the stage when the larvae are biting through the shells. The oxide and acetate proved to be surprisingly innocuous.
Unless it is felt to be too poisonous E600 is worthy of consideration as an insecticide against Pieris eggs and larvae, since it is highly effective as a contact insecticide and also has some systemic action.     

Studies on the mechanism of action of peptides attacking smooth muscles. III. The effect of N-azylation on the activity of C-terminal partial sequences of eledoisin, physalaemin and substance P on the guinea pig ileum]

C-terminal pentapeptides of eledoisin, physalaemin, and the substance P, when N-substituted with acetyl, halogenacetyl and other acyl residues, are increased in their action more than 100fold, reaching the activity of acylated hexa- and heptapeptides. The effect found with a number of compounds is interpreted as the influence of predominantly hydrophobic substituents upon the peptide sequence essential for the action. Polar groups in the acylic residue seem to cause additional increase in action.     

Cyclic AMP-lowering mediator of insulin

What appears to be a mediator of insulin action has been successfully produced in rat adipocytes plasma membrane upon its treatment with insulin at concentrations of 50-200 microunits/ml. This apparent mediator, when isolated and presented to adipocyte cells, mimics insulin action in the lowering of hormonally stimulated cAMP levels as well as in stimulating lipogenesis and antilipolysis. The cAMP-lowering activity of such a mediator can be quantitated as insulin-activity equivalents. Insulin at 200 microunits/ml causes, in terms of insulin-activity equivalents, a generation of as much as 50 times more of insulin mediator. The magnitude of amplification is even greater when the amount of insulin bound to its receptor is taken into account in this calculation. The action of insulin in the generation of cAMP-lowering mediator is abolished by the insulin antibody. Inactive insulin analogs do not effectively generate such a mediator activity. On the other hand, while the cAMP-lowering action of insulin shown in the bioassay system is completely inhibited by the insulin antibody, the action of such a mediator is only slightly inhibited by the same antibody. The mediator has a low molecular weight and attributes that resemble a peptide. It can be separated from insulin in a Sephadex G-25 column and has a molecular size smaller than the insulin A-chain but larger than ATP. The molecular weight of this mediator is similar to the insulin mediators isolated by other investigators. In view of the fact that it is small in size and mimics several actions of insulin when used in extracellular situations, its theoretical, as well as practical, implications are substantial.     

The cytogenetic action of ifosfamide,mesna, and their combination on peripheral rabbit lymphocytes: an in vivo/in vitro cytogenetic study

Ifosfamide (IFO) is an alkylating nitrogen mustard, administrated as an antineoplasmic agent. It is characterized by its intense urotoxic action, leading to hemorrhagic cystitis. This side effect of IFO raises the requirement for the co-administration with sodium 2-sulfanylethanesulfonate (Mesna) aiming to avoid or minimize this effect. IFO and Mesna were administrated separately on rabbit’s lymphocytes in vivo, which were later developed in vitro. Cytogenetic markers for sister chromatid exchanges (SCEs), proliferation rate index (PRI) and Mitotic Index were recorded. Mesna’s action, in conjunction with IFO reduces the frequency of SCEs, in comparison with the SCEs recordings obtained when IFO is administered alone. In addition to this, when high concentrations of Mesna were administered alone significant reductions of the PRI were noted, than with IFO acting at the same concentration on the lymphocytes. Mesna significantly reduces IFO’s genotoxicity, while when administered in high concentrations it acts in an inhibitory fashion on the cytostatic action of the drug.     

Na channels that remain open throughout the cardiac action potential plateau.

In this paper we report the direct measurement of rare Na channel events that occur during the cardiac action potential, viz., channels that open at the upstroke and remain open throughout the plateau and early repolarization phase. The technique we use allows us to record channel activity and action potentials at the same time; thus, we are certain of when the Na channels open and when they finally close. The slow Na channels have the same voltage dependence, single-channel conductance, and TTX sensitivity as the fast Na channels, and they conduct Li. It therefore seems likely that the fast and the slow currents flow through the same channel. If this interpretation is correct, then the Na channel not only initiates the action potential but also helps to maintain its plateau. It is possible that the slow Na currents represent a separate collection of channels rather than a low-probability state of the fast Na channels. Regardless of which interpretation is correct, the present experiments allow us to assess the effect of the slow currents on action potential shape and on sustained Na entry.     

GA,ABA, phenol interaction in the control of growth: Phenolic compounds as effective modulators of GA-ABA interaction in radish seedlings

Abscisic acid, a potent growth inhibitor inhibits hypocotyl growth ofRaphanus sativus seedlings. Phenolic compounds,viz., trans-cinnamic acid, chlorogenic acid, ferulic acid, salicylic acid, tannic acid and quercetin when applied with ABA, antagonize ABA action and restore normal seedling growth. Gibberellic acid promotes hypocotyl growth and on combined application with ABA, the ratio of their concentrations determines the course of the resultant growth. This interaction can be modulated by phenolic compounds. Phenolic compounds in low concentrations when present together with GA and ABA, favour GA-induced growth by antagonizing the inhibitory influence of ABA. The inhibitory action of abscisic acid on a wide range of growth processes is so far known to be reversed only by growth promoting hormones,viz., IAA, GA and cytokinins. Antagonistic action of phenolic compounds towards ABA, and increasing the action of GA when present together with GA and ABA, establishes a dual role to this class of compounds; balancing the effect of both growth promoting and growth inhibiting hormones. Part I.