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Planets with radii between that of the Earth and Neptune (hereafter referred to as ‘sub-Neptunes’) are found in close-in orbits around more than half of all Sun-like stars1,2. However, their composition, formation and evolution remain poorly understood3. The study of multiplanetary systems offers an opportunity to investigate the outcomes of planet formation and evolution while controlling for initial conditions and environment. Those in resonance (with their orbital periods related by a ratio of small integers) are particularly valuable because they imply a system architecture practically unchanged since its birth. Here we present the observations of six transiting planets around the bright nearby star HD 110067. We find that the planets follow a chain of resonant orbits. A dynamical study of the innermost planet triplet allowed the prediction and later confirmation of the orbits of the rest of the planets in the system. The six planets are found to be sub-Neptunes with radii ranging from 1.94R⊕to 2.85R⊕. Three of the planets have measured masses, yielding low bulk densities that suggest the presence of large hydrogen-dominated atmospheres.

HATSouth is the world's first network of automated and homogeneous telescopes that is capable of year-round 24 hr monitoring of positions over an entire hemisphere of the sky. The primary scientific goal of the network is to discover and characterize a large number of transiting extrasolar planets, reaching out to long periods and down to small planetary radii. HATSouth achieves this by monitoring extended areas on the sky, deriving high precision light curves for a large number of stars, searching for the signature of planetary transits, and confirming planetary candidates with larger telescopes. HATSouth employs six telescope units spread over three prime locations with large longitude separation in the southern hemisphere (Las Campanas Observatory, Chile; HESS site, Namibia; Siding Spring Observatory, Australia). Each of the HATSouth units holds four 0.18 m diameter f/2.8 focal ratio telescope tubes on a common mount producing an 8.2° × 8.2° field of view on the sky, imaged using four 4 K × 4 K CCD cameras and Sloan rfilters, to give a pixel scale of 3.7? pixel-1. The HATSouth network is capable of continuously monitoring 128 square arc degrees at celestial positions moderately close to the anti-solar direction. We present the technical details of the network, summarize operations, and present detailed weather statistics for the three sites. Robust operations have meant that on average each of the six HATSouth units has conducted observations on ?500 nights over a 2 years time period, yielding a total of more than 1 million science frames at a 4 minute integration time and observing ?10.65 hr day-1on average. We describe the scheme of our data transfer and reduction from raw pixel images to trend-filtered light curves and transiting planet candidates. Photometric precision reaches ?6 mmag at 4 minute cadence for the brightest non-saturated stars at r? 10.5. We present detailed transit recovery simulations to determine the expected yield of transiting planets from HATSouth. We highlight the advantages of networked operations, namely, a threefold increase in the expected number of detected planets, as compared to all telescopes operating from the same site.

In situ hybridization was used to determine whether genes for neuropeptides [substance P/neurokinin A (SP/NKA), calcitonin gene-related peptide (CGRP), somatostatin (SOM), neuropeptide tyrosine (NPY) and cholecystokinin (CCK)] are expressed in inferior ganglia of the vagus (nodose) and glossopharyngeal (petrosal) nerves. Synthetic oligodeoxyribonucleotides, complementary to the cognate, mRNAs were labeled with [32P] or [35S], and hybridized to 10 µm thick sections of unperfused tissue which were then processed for film and emulsion autoradiography. We found numerous, clustered neuronal perikarya throughout the nodose and petrosal ganglia that expressed preprotachykinin A (SP/NKA) and CGRP mRNAs to varying degrees. Neurons expressing preproSOM mRNA were less abundant and more scattered throughout both ganglia. Notably, we found mRNA for NPY in cells (usually 5–10 per section) in both ganglia. To our knowledge, this is first evidence for NPY in these sensory ganglia. In contrast to previous immunohistochemical findings, we found no evidence for expression of preproCCK in either the nodose or petrosal ganglia. The present findings demonstrate that cells of the nodose and petrosal ganglia express the genes for a number of neuropeptides that are presumably involved with transmission of visceral sensory afferent information to higher order neurons of the central nervous system.

1. We investigated the effects of serotonin (5‐hydroxytryptamine, 5‐HT) on whole‐cell barium currents through calcium channels in visualized neonatal rat hypoglossal motoneurones (HMs) in a thin brainstem slice preparation. 2. High voltage‐activated (HVA) currents were elicited by depolarizing voltage steps from ‐70 to 0 mV; low voltage‐activated (LVA) currents were evoked using steps to between ‐30 and ‐40 mV from hyperpolarized potentials (< ‐80 mV). 5‐HT (1.0 microM) inhibited HVA currents by at least 10% in 70% of HMs tested (n = 99); in those responsive neurones, 5‐HT decreased HVA current by 22 +/‐ 1.3% (mean +/‐ S.E.M.). In contrast, 5‐HT had no effect on LVA current amplitude in HMs (n = 7). 3. Calcium current inhibition was mimicked by 5‐carboxamidotryptamine maleate (5‐CT), a 5‐HT1 receptor agonist, and by R(+)‐8‐hydroxydipropylaminotetralin hydrobromide (8‐OH‐DPAT), a specific 5‐HT1A agonist; N‐(3‐trifluoromethylphenyl) piperazine hydrochloride (TFMPP), a 5‐HT1B agonist, was without effect. The effect of 5‐HT was blocked by the 5‐HT1A antagonist 1‐(2‐methoxyphenyl)‐4‐[4‐(2‐phthalimido)butyl]piperazine hydrobromide (NAN‐190) but not by ketanserin, a 5‐HT2A/2C antagonist. Although R(‐)‐1‐(2,5‐dimethoxy‐4‐iodophenyl)‐2‐aminopropane hydrochloride (DOI), a 5‐HT2A/2C agonist, mimicked the current inhibition by 5‐HT, it was ineffective in the presence of NAN‐190. These data indicate that 5‐HT1A receptors mediate calcium current inhibition by 5‐HT. 4. Following application of either omega‐conotoxin‐GVIA (omega‐CgTX) or omega‐agatoxin‐IVA (omega‐Aga‐IVA), to block N‐ and P‐type components of calcium current, the 5‐HT‐sensitive current was reduced; 5‐HT had no effect on the current remaining after application of both toxins. Thus, 5‐HT inhibits both N‐ and P‐type calcium currents in neonatal HMs. 5. Inhibition of HVA current by 5‐HT was irreversible, and subsequent applications of 5‐HT were occluded, when GTP gamma S was substituted for GTP in the pipette. In addition, inhibition of HVA current by 5‐HT was relieved following depolarizing prepulses. These data indicate that inhibition of calcium channels by 5‐HT is mediated by G proteins. 6. Under current clamp, both 5‐HT and 8‐OH‐DPAT decreased the amplitude of the after‐hyperpolarization (AHP) that followed action potentials, indicating involvement of a 5‐HT1A receptor.(ABSTRACT TRUNCATED AT 400 WORDS)

1. The repetitive firing properties of neonatal and adult rat hypoglossal motoneurones (HMs) were investigated in a brainstem slice preparation. Neonatal HMs could be classified into two main groups: (1) neurones with a decrementing or adapting firing pattern (type D); exhibiting an early and a late phase; and (2) neurones with an incrementing or accelerating firing pattern (type I). 2. The pattern of repetitive firing changed markedly during development. While most HMs recorded from young rats (< postnatal day (P) 4) were type D, the majority of HMs recorded during the second postnatal week were type I. In adults (> P21), nearly all HMs had a decrementing firing pattern, characterized by a brief period of adaptation and high steady‐state firing rates. 3. The calcium‐dependent after‐hyperpolarization (AHP) was shortest in type I neonatal HMs, and decreased in amplitude during trains of action potentials (APs). In type D neurones, these same trains caused a slight enhancement of AHP amplitude. In adult HMs, with a decrementing firing pattern, trains of APs also caused summation of the AHP. 4. Type D neonatal HMs showed a progressive prolongation of the AP during repetitive firing. In contrast, type I neonatal HMs had almost no change in AP duration. In adult HMs the AP was short and experienced only a modest increase in duration during fast repetitive firing. 5. The function relating steady‐state firing frequency to injected current (f‐I curve) was linear. The mean steady‐state f‐I slope was significantly higher in neonates than in adults (approximately 30 vs. approximately 20 Hz nA‐1), and was weakly correlated with input resistance. The f‐I slope was negatively correlated with AHP duration in neonatal HMs only. In addition, for a given AHP duration the slope was higher in neonatal HMs. 6. Two threshold behaviours were observed among neonatal HMs: (a) a progressive rhythmic firing threshold, and (b) a sudden transition from subthreshold to regular repetitive firing. Current threshold for repetitive firing was strongly correlated with cell input conductance. Type I neonatal HMs had higher minimal steady firing rates (fmin) than type D HMs. In neonates, fmin was strongly correlated with AHP duration. Adult HMs showed a weaker correlation between these two parameters, and fmin was higher than predicted by AHP duration. 7. In summary, HMs responded to depolarizing current pulses with different firing patterns during postnatal development.(ABSTRACT TRUNCATED AT 400 WORDS)

Bus privatization in Great Britain D. Bayliss, OBE, FEng, FICE grew and, following the 1968 Transport Act, the National Bus Company (NBC) and the Scottish Bus Group (SBG) were set up as holding companies for a myriad of local bus companies. 4. The NBC was the holding company for 42 operating subsidiaries running over 40% of bus ser vices in England and Wales. Its ser vices were to be found in almost all locales and were usually particularly heavily represented on the fringes of larger towns and cities, in smaller towns and in rural areas...

Sodium efflux in three populations of the freshwater amphipod Corophium curvispinum were measured seasonally over a 6-year period and compared to rates recorded in 1980. While continuing to show relatively high Na+ loss rates, compared to other freshwater amphipod species, sodium permeability (PNa) has decreased significantly in the medium term (post 1983). PNa also shows seasonal fluctuations in all populations. Changes in body sodium content (BNa) and blood [Na+] were found during this period and some alteration of the kinetic characteristics, Km and Vmax, of the sodium uptake system has occurred. Acclimation to different [Na+] media, and to low and high temperatures produced significant changes in Na+ efflux. The importance of acclimation (acclimatization) and selection in reducing passive Na+ loss and effecting changes in Na+ regulation of this colonizing species are assessed in relation to environmental changes.

1. Single-electrode voltage clamp recordings in a rat brain stem slice preparation were used to determine the characteristics and postnatal development of a hyperpolarization-activated inward current (Ih) in hypoglossal motoneurons (HMs). 2. In young adult HMs (> P21), a noninactivating, time- and voltage-dependent inward current was evident during hyperpolarizing voltage steps to membrane potentials negative to approximately -65 mV from depolarized holding potentials [Vh = -56.2 +/- 1.0 (SE) mV]. The averaged reversal potential (Erev) of the inward current, estimated using an extrapolation procedure, was -38.8 +/- 2.9 mV (n = 5), suggesting that a mixed cationic current underlies inward rectification in HMs. 3. The voltage dependence of Ih activation was determined from tail current relaxations that followed a family of voltage steps to different membrane potentials. Normalized tail current amplitudes were well-fitted with a single Boltzman function with a half-activation at -79.8 +/- 0.7 mV and slope factor = 5.3 +/- 0.3 (n = 8). 4. Time constants of Ih activation and deactivation were voltage-dependent. Activation proceeded more quickly with larger hyperpolarizing voltage steps; time constants averaged 389, 181, and 134 ms at -69, -82, and -95 mV, respectively (n = 6). Ih deactivated during depolarizing voltage steps from hyperpolarized holding potentials. Deactivation was faster with larger depolarizing steps; time constants averaged 321, 215, and 107 ms at -80, -71, and -62 mV, respectively (n = 4). 5. Ih was sensitive to extracellular cesium but relatively insensitive to extracellular barium. The current amplitude near half-activation (approximately -84 mV) was almost completely blocked (to 11% of control) by Cs+ (3 mM, n = 3) but was reduced to only 85 and 60% in 0.5 (n = 2) and 2 mM Ba2+ (n = 3), respectively. 6. There was a marked increase in the amplitude of Ih during postnatal development of HMs. Measured near half-activation, Ih was approximately 10-fold larger in adult (> or = P21; n = 20) than in neonatal HMs (< or = P8; n = 7). Input conductance (GN) was only threefold higher in the same sample of HMs. There were no apparent differences in the voltage dependence or Erev of Ih between neonatal and older HMs. These results suggest that the increased amplitude of Ih results from an increase in Ih current density.(ABSTRACT TRUNCATED AT 400 WORDS)

1. We used conventional intracellular recording techniques in 400-microns-thick slices from the brain stems of juvenile rats to investigate the action of norepinephrine (NE) on subthreshold and firing properties of hypoglossal motoneurons (HMs). 2. In recordings in current-clamp mode, 50 or 100 microM NE elicited a reversible depolarization accompanied by an increase in input resistance (RN) in all HMs tested (n = 74). In recordings in single-electrode voltage-clamp mode, NE induced a reversible inward current (INE) accompanied by a reduction in input conductance. The average reversal potential for INE was -104 mV. The NE responses could be elicited in a Ca(2+)-free solution containing tetrodotoxin, indicating that they were postsynaptic. 3. The NE response could be blocked by the alpha-adrenoceptor antagonist prazosin, but not by the beta-adrenoceptor antagonist propranolol, and could be mimicked by the alpha 1-adrenoceptor agonist phenylephrine but not by the alpha 2-adrenoceptor agonist UK 14,304 or by the beta-adrenoceptor agonist isoproterenol when alpha-adrenoceptors were blocked. 4. Substitution of barium for calcium in the perfusion solution blocked the increase in RN in response to NE without completely blocking the depolarization. Replacement of sodium chloride with choline chloride in the barium-substituted perfusion solution blocked the remaining depolarization. 5. The neuropeptide thyrotropin-releasing hormone (TRH), which also depolarizes and increases the RN of HMs, occluded the response of HMs to NE. 6. NE altered HM firing properties in three ways: it always lowered the minimum amount of injected current needed to elicit repetitive firing, it increased the slope of the firing frequency versus injected current relation in 8 of 14 cells tested, and it increased the delay from the onset of the depolarizing current pulse to the first evoked spike in all cells tested. 7. We conclude that NE acts directly on alpha 1-adrenoceptors to increase the excitability of HMs. It does this by reducing a barium-sensitive resting potassium current and activating a barium-insensitive inward current carried primarily by sodium ions. A portion of the intracellular pathway for these actions is shared by TRH. In addition, there is evidence that NE alters HM firing patterns by affecting currents that are activated following depolarization.

Sorting out the buses D.Bayliss, OBE, BSc W The paperreviews recent trends in the UK F'roc. Instn Ciu. Engrs Mun. Engr, 1992.93, Dec., 215-218 bus industry and highlights the reductions in costs and ridership and increases in fares since deregulation. It looks at the problems of buses today and identifies the ageing fleets and growing traffic congesfor tion as major problems. The main need improvements are argued to be an increased service stability, better passenger information, rejuvenationof the bus parc and more intensive and extensive bus priorities...

Critical Issues in Urban Economic Development, Vol. 1, V. A. HAUSNER (Ed.), Clarendon Press, Oxford/ESRC (1986). xviii + 235 pp. £22.50 (hbk). ISBN 0 19 823266 7.The Geography of De-Industrialization, R. MARTIN and R. ROWTHORN [Eds.], Macmillan Education, Basingstoke, Hants. (1986). xxiii + 365 pp. £30.00 [hbk]. £8.95 [pbk]. ISBN 0333 37124 [hbk]. ISBN 0 333 37125 0 [pbk].New Firms and Regional Development in Europe, D. KEEBLE and E. WEVER (Eds.), Croom Helm, Beckenham, Kent (1986). 322 pp. £19.95 (hbk). ISBN 0 7099 1577 2.Restructuring the Regions: Analysis, Policy Model and Prognosis, D. WADLEY, Organisation for Economic Cooperation and Development, Paris (1986), 172 pp. No price given. ISBN 92 64 12868 9.Philosophy and Human Geography: An Introduction to Contemporary Approaches, 2nd edition. R. J. JOHNSTON, Edward Arnold, London (1986), xi + 178 pp. No price given. ISBN 0 7131 6490 5.Medical Geography: Progress and Prospect, M. PACIONE (Ed.), Croom Helm, Beckenham, Kent (1986). 337 pp. £27.95 (hbk). ISBN 0 7099 4044 1.Geography, Planning and Policy Making, P. T. KIVELL and J. T. COPPOCK (Eds.), Geo Books, Norwich (1986). viii + 302 pp. £25.00 (hbk). ISBN 0 86094 211 2.Local Planning in Practice, M. BRUTON and D. NICHOLSON, Hutchinson Education, London (1986). 452 pp. £12.95 (pbk). ISBN 0 09 1653819.A Theory of Planning, J. SILLINCE, Gower, Aldershot, Hants (1986). viii + 218 pp. No price given. ISBN 0 566 05231 8.Public Transport: Its Planning, Management and Operation, 2nd edition, P. WHITE, Hutchinson Education, London (1986), 222 pp. £12.95 (pbk). ISBN 0 09 1674611.The Contemporary British City, P. LAWLESS and C. RABAN (Eds.), Harper and Row, London (1986), 76 pp. £7.50. ISBN 0 06 318340 4.Spatial Interaction Modelling and Residential Choice Analysis, W. VAN LIEROP, Gower, Aldershot, Hants. (1986). xii + 286 pp. £29.50 (hbk). ISBN 0 566 05036 6.Change and Development in Rural Ireland, P. BREATHNACH and M. E. CRAWLEY (Eds.), Special Publication No. 1, Geographical Society of Ireland, Cardinal Press, Maynooth (1986), iv + 91 pp. £3.00. ISBN 0 9510402 19.The Rice Economies: Technology and Development in Asian Societies, F. BRAY, Basil Blackwell, Oxford (1986), xvii + 254 pp. No price given. ISBN 0 631 14877 9.

1. The role of multiple potassium conductances in action potential repolarization and repetitive firing behavior of hypoglossal motoneurons was investigated using intracellular recording techniques in a brain stem slice preparation of the neonatal rat (0-15 days old). 2. The action potential was followed by two distinct afterhyperpolarizations (AHPs). The early one was of short duration and is termed the fAHP; the later AHP was of longer duration and is termed the mAHP. The amplitudes of both AHPs were enhanced by membrane potential depolarization (further from EK). In addition, their amplitudes were reduced by high extracellular K+ concentration, suggesting that activation of potassium conductances underlies both phases of the AHP. 3. Prolongation of the action potential and blockade of the fAHP were observed after application of 1) tetraethylammonium (TEA) (1-10 mM) and 2) 4-aminopyridine (4-AP) (0.1-0.5 mM). Calcium channel blockers had little or no effect on the fAHP or action potential duration. 4. The size of the mAHP was diminished by 1) manganese, 2) lowering external Ca2+, 3) apamin, and 4) intracellular injection of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) suggesting that influx of calcium activates the potassium conductance that underlies the mAHP. 5. The mAHP was unaffected by nifedipine (20 microM), but was strongly reduced by focal application of omega-conotoxin GVIA, suggesting that N-type calcium channels represent the major calcium influx pathway for activation of the calcium-dependent K+ conductance underlying the mAHP. 6. Repetitive firing properties were investigated by injecting long-duration depolarizing current pulses. Steady-state firing rose linearly with injected current amplitude. The slope of the firing frequency-current (f-I) relationship averaged approximately 30 Hz/nA in control conditions. Blockade of the conductance underlying the mAHP caused a marked increase in the minimal repetitive firing frequency and in the slope of the f-I plot, indicating a prominent role for the conductance underlying the mAHP in controlling repetitive firing behavior. 7. We conclude that action potential repolarization and AHPs are due to activation of pharmacologically distinct potassium conductances. Whereas repolarization of the action potential and the fAHP involves primarily a voltage-dependent, calcium-independent potassium conductance that is TEA- and 4-AP-sensitive, the mAHP requires the influx of extracellular calcium and is apamin sensitive. Activation of the calcium-activated potassium conductance greatly influences the normal repetitive firing of neonatal hypoglossal motoneurons.

1. The role of calcium conductances in action potential generation and repetitive firing behavior of hypoglossal motoneurons (HMs) was investigated using intracellular recording and patch-clamp techniques in a brain stem slice preparation of neonatal rats (0-15 days old). 2. The action potential was followed by an afterdepolarization (ADP). The ADP was voltage dependent, increasing with membrane hyperpolarization. Raising the extracellular Ca2+ concentration or replacing Ca2+ with Ba2+ increased the ADP amplitude, whereas replacement of Ca2+ with Mn2+ blocked it. The ADP was partially reduced by amiloride and low concentrations of Ni2+. 3. The firing behavior of individual neonatal HMs was influenced by membrane potential. From depolarized potentials, HMs fired tonically in response to a depolarizing current pulse, whereas from more hyperpolarized membrane potentials (more negative than -70 mV), a subset of HMs fired an initial burst of action potentials followed by a prolonged afterhyperpolarization and tonic firing. The incidence of burst-firing behavior was highest among young motoneurons and disappeared by the tenth postnatal day. In addition, prominent rebound depolarizations characterized the response of neonatal motoneurons to hyperpolarizing prepulses. 4. Pharmacological characterization of the rebound depolarization demonstrated that it was calcium dependent. Its amplitude was insensitive to tetrodotoxin and it was eliminated by replacement of Ca2+ with Mn2+ or addition of Ni2+. Amiloride (1-1.5 mM) had no effect on the rebound response or burst firing. 5. The presence of high-threshold calcium spikes was detected at all postnatal ages, but only after blockade of outward currents with intra- or extracellular tetraethylammonium. The high-threshold calcium spikes were greatly enhanced when Ba2+ replaced Ca2+. 6. Calcium currents of neonatal HMs were characterized in whole-cell patch-clamp recordings of thin medullary slices under conditions that minimized voltage-dependent Na+ and K+ currents. Low voltage-activated (LVA) and a high voltage-activated (HVA) calcium current components were identified on the basis of their voltage thresholds for activation, kinetics of inactivation, and pharmacological sensitivity. 7. The LVA calcium current began to activate at around -60 mV and inactivated nearly completely within 100 ms. Complete steady-state inactivation occurred at potentials more positive than -60 mV. The LVA current was selectively reduced by 1 mM amiloride (31%). 8. A larger-amplitude calcium current activated at potentials around -35 mV. Inactivation of this HVA current was slower than that of the LVA current and incomplete. About 1/3 of this current was sensitive to 1 microM omega-conotoxin GVIA, whereas a smaller fraction was blocked by 10 microM nifedipine.(ABSTRACT TRUNCATED AT 400 WORDS)

A Working Party considering ‘Competence to Practise’ circulated a questionnaire in March 1982 to all district occupational therapists and equivalent grades in social service departments in the UK to survey current practice in occupational therapy. The results indicate that a wide variety of skills are required by basic grade occupational therapists to deal with a relatively small range of clinical problems for a large number of patients/clients in the middle and older age groups. The information will act as a baseline for further work to proceed to determine what relevant knowledge, skills and attitudes are required of basic grade occupational therapists in order to practise competently.

1. The hypoglossal motor nucleus contains binding sites for the neuropeptide thyrotropin-releasing hormone (TRH) and is innervated by TRH-containing fibers. Although excitatory effects of TRH on hypoglossal motoneurons (HMs) have been described, the ionic mechanisms by which TRH exerts such effects have not been fully elucidated. Therefore, we investigated the effects of TRH on HMs in transverse slices of rat brainstem with intracellular recording techniques. 2. TRH was applied by perfusion (0.1-10 microM) or by pressure ejection (1.0 microM), while HMs were recorded in current or voltage clamp. In all cells tested, TRH caused a depolarization and/or the development of an inward current. These effects were fully reversible, dose dependent, and showed only modest desensitization with long applications. In addition, although TRH increased synaptic activity in many cells, the depolarizing response to TRH was maintained in tetrodotoxin (0.5-1.0 microM)-containing or in a nominally Ca(2+)-free perfusate containing 2 mM Mn2+. Thus TRH acts directly on HMs to cause the depolarization. 3. Hyperpolarizing current (or voltage) steps superimposed on the TRH-induced depolarization (or inward current) revealed a decreased input conductance. Extrapolated instantaneous current-voltage relationships obtained before and at the peak of the response to TRH intersected (i.e., reversed) at -101 mV, negative to the expected K+ equilibrium potential (EK). When extracellular [K+] was raised from 3 to 12 mM, the reversal potential was shifted in the depolarizing direction and the magnitude of the TRH-induced depolarization was diminished. Moreover, the TRH response was enhanced in size from depolarized potentials (i.e., further from EK). Taken together, these results indicate that TRH depolarizes HMs, in part, by decreasing a resting K+ conductance. 4. Similar to TRH, bath-application of 2 mM Ba2+ caused a depolarization associated with decreased conductance, suggesting that Ba2+ also blocks a resting K+ conductance. The Ba(2+)-sensitive and TRH-sensitive resting K+ conductances are apparently identical; in the presence of Ba2+, the customary TRH-induced decrease in conductance was occluded. 5. It is noteworthy that the TRH-induced inward current (ITRH), although diminished, was not entirely blocked by Ba2+. This second Ba(2+)-insensitive component of ITRH was not associated with a measurable change in input conductance. It was especially evident during current-clamp recordings, when the diminutive TRH-induced current was still capable of causing a substantial depolarization. The ionic basis of the residual TRH-induced inward current remains to be determined. 6. We investigated the functional consequences of these mechanisms of action of TRH on spike firing behavior of HMs.(ABSTRACT TRUNCATED AT 400 WORDS)

In South Australian mangroves Lepsiella vinosa feeds on two species of barnacles, Balanus amphitrite and Elminius modestus, and only attacks other types of prey if no barnacles are available. Laboratory experiments indicate that L. vinosa can be trained to either species and switches in terms of Murdoch's (1969) model.

1.Chloride influx and efflux rates were measured in three populations of the freshwater amphipodCorophium curvispinum, a recent invader of freshwaters in the English Midlands.2.Chloride permeability (PCl) was found to be greater than in other freshwater crustaceans. There were differences in PCl between populations (range 3.5–5.5·10-8 m sec-1). PCl was reduced by 50% after acclimation to low chloride media (0.5 mM [Cl-]).3.The kinetic characteristics of the saturable chloride uptake systems (60% SCN- sensitive, but not significantly inhibited by 10-4M external amiloride) of different populations were compared, and the effects of short-term acclimation (=7 days) to low and high [Cl-] media studied.4.Acclimation to different [Cl-] media had more marked effects on PCl than on the uptake parameters studied, although some changes in apparent affinity (Km) and uptake rate (Vmax) occurred.5.Comparison of Cl- balance points with recently measured Na+ values in populations ofCorophium curvispinum, with reference to environmental [Na+] and [Cl-], suggest that low chloride, not low sodium may, at present, limit its distribution in freshwaters.

We have examined the effect on respiration of the steroid hormone progesterone, administered either intravenously or directly into the medulla oblongata in anesthetized and paralyzed male and female cats. The carotid sinus and vagus nerves were cut, and end-tidal PCO2 and temperature were kept constant with servo-controllers. Phrenic nerve activity was used to quantitate central respiratory activity. Repeated doses of progesterone (from 0.1 to 2.0 micrograms/kg, cumulative) caused a sustained (greater than 45 min) facilitation of phrenic nerve activity in female and male cats; however, the response was much more variable in females. Progesterone injected into the region of nucleus tractus solitarii, a respiratory-related area in the medulla oblongata, also caused a prolonged stimulation of respiration. Progesterone administration at high concentration by both routes also caused a substantial hypotension. Identical i.v. doses of other classes of steroid hormones (17 beta-estradiol, testosterone, and cortisol) did not elicit the same respiratory effect. Pretreatment with RU 486, a progesterone-receptor antagonist, blocked the facilitatory effect of progesterone. We conclude that progesterone acts centrally through a steroid receptor-mediated mechanism to facilitate respiration.

Concurrent engineering is seen as a philosophy with the aim of simultaneously involving suppliers and customers at an early stage in the design process. The transfer of technology has been established as the key element in this process, together with the coordination of the product development process. An ESPRIT (7752) project at De Montfort University has benchmarked the levels of concurrent engineering (CE) of manufacturing companies in the United Kingdom. This has shown, in general, that two fundamental methods for the implementation of CE exist, these being specialized multi-functional teams and multi-functional teams using computer optimization, the latter being seen as the way forward. This paper examines the use of an expert system toolkit, particularly in the design for manufacture (DFM) process. Dealing with knowledge acquisition, the function as well as the structure of component elements is represented. The paper also describes work by De Montfort University in integrating an expert and computer aided design (CAD) system that meets the requirements for accomplishing the concept of design for manufacture. In the future intelligent manufacturing systems (IMS) aimed at systematizing the know-how will be used, which will be of particular value in showing how to use knowledge effectively.

MEETING REPORT Sustainability--a future for transport? Reporter C.G.B. Mitchell David Bayliss, Chairman of the ICE Transport Board, welcomed delegates. Civil engineers are responsible for changes in society and must respect the needs and wishes of society. There is increasing concern over the effects of transport infrastructure and operations for sustainability. The ICE has published documents on sustainability, particularly the SAID report (sustainable and acceptable infrastructure development). This seminar is to explore the issues. people and between types of need. It is complemented by several principles...

We report the discovery of HATS-15 b and HATS-16 b, two massive transiting extrasolar planets orbiting evolved (?10 Gyr) main-sequence stars. The planet HATS-15 b, which is hosted by a G9 V star (mag), is a hot Jupiter with mass of and radius of , and it completes its orbit in about 1.7 days. HATS-16 b is a very massive hot Jupiter with mass of and radius of it orbits around its G3 V parent star (mag) in ?2.7 days. HATS-16 is slightly active and shows a periodic photometric modulation, implying a rotational period of 12 days, which is unexpectedly short given its isochronal age. This fast rotation might be the result of the tidal interaction between the star and its planet.