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Background Where the critical view of safety cannot be established during cholecystectomy, certain salvage techniques are indicated to reduce the likelihood of bile duct injury. The present study describes a salvage technique termed the “laparoscopic lumen-guided cholecystectomy” (LLC) and reports its peri-operative outcomes. Method A summary of the technique is as follows: (1) Hartmann’s pouch is incised and stones are evacuated; (2) the cystic anatomy is inspected from the inside of the gallbladder; (3) the lumen is used to guide retrograde dissection towards the cystic pedicle; (4) cystic duct control is achieved if deemed safe. LLC cases performed between June 2020 and January 2022 in a single health board were included. The operative details and peri-operative outcomes of the technique are reported and compared to cases of similar difficulty where the LLC was not attempted. Results LLC was performed in 4.6% (27/587) of cases. In all 27 cases, LLC was performed for a “frozen” cholecystohepatic triangle. Hartmann’s pouch was completely excised in all cases (27/27) and cystic duct control was achieved in 85.2% of cases (23/27). No cases of bile leak or ductal injury were reported. Rates of bile leak, post-operative complications and ERCP were lower following LLC compared to the group where LLC was not attempted (p Conclusion LLC is a safe salvage technique and should be considered in cases where the critical view of safety cannot be established. The technique achieves cystic duct control in the majority of cases and favourable outcomes in the face of a difficult cholecystectomy.

The Roman High- (RHA) and Low-(RLA) avoidance rat lines/strains were generated through bidirectional selective breeding for rapid (RHA) vs. extremely poor (RLA) two-way active avoidance acquisition. Compared with RLAs and other rat strains/stocks, RHAs are characterized by increased impulsivity, deficits in social behavior, novelty-induced hyper-locomotion, impaired attentional/cognitive abilities, vulnerability to psychostimulant sensitization and drug addiction. RHA rats also exhibit decreased function of the prefrontal cortex (PFC) and hippocampus, increased functional activity of the mesolimbic dopamine system and a dramatic deficit of central metabotropic glutamate-2 (mGlu2) receptors (due to a stop codon mutation at cysteine 407 in Grm2 -cys407*-), along with increased density of 5-HT2A receptors in the PFC, alterations of several synaptic markers and increased density of pyramidal "thin" (immature) dendrític spines in the PFC. These characteristics suggest an immature brain of RHA rats, and are reminiscent of schizophrenia features like hypofrontality and disruption of the excitation/inhibition cortical balance. RHA rats represent a promising heuristic model of neurodevelopmental schizophrenia-relevant features and comorbidity with drug addiction vulnerability.

Background Where the critical view of safety cannot be established during cholecystectomy, certain salvage techniques are indicated to reduce the likelihood of bile duct injury. The present study describes a salvage technique termed the “laparoscopic lumen-guided cholecystectomy” (LLC) and reports its peri-operative outcomes. Methods A summary of the technique is as follows: (1) Hartmann's pouch is incised and stones are evacuated; (2) the cystic anatomy is inspected from the inside of the gallbladder; (3) the lumen is used to guide retrograde dissection towards the cystic pedicle; (4) cystic duct control is achieved if deemed safe. LLC cases performed between June 2020 and January 2022 in a single health board were included. The operative details and peri-operative outcomes of the technique are reported and compared to cases of similar difficulty (Nassar ≥4) where the LLC was not attempted. Results LLC was performed in 4.6% (27/587) of cases. In all 27 cases, LLC was performed for a “frozen” cholecystohepatic triangle. Hartmann's pouch was completely excised in all cases (27/27) and cystic duct control was achieved in 85.2% of cases (23/27). No cases of bile leak or ductal injury were reported. Rates of bile leak, post-operative complications and ERCP were lower following LLC compared to the group where LLC was not attempted (p Conclusions LLC is a safe salvage technique and should be considered in cases where the critical view of safety cannot be established. The technique achieves cystic duct control in the majority of cases and favourable outcomes in the face of a difficult cholecystectomy.

Background Medical educational courses can be successful from an immediate feedback perspective but not lead to new behaviour or organizational changes in the workplace. The aim of this study was to assess the self-perceived impact of the Reanima European Trauma Course (R-ETC) on trainees’ behaviour and organizational change. Methods A 40-item questionnaire based on Holton's Evaluation Model was used to evaluate the candidate's perceptions. Results were analysed with descriptive and inferential statistical analysis using non-parametric tests with α = 0.05. Results Out of 295 participants, 126 responded to the survey. Of these, 94% affirmed that the R-ETC modified their approach to trauma patients and 71.4% described a change in their behaviour. Post-course responders changed their behaviour in their initial approach to trauma care in the non-technical skills of communication, prioritisation and teamwork. Being an R-ETC instructor strongly influenced the acquisition of new material and this group were able to implement changes in attitudes. Individuals with no previous trauma course experience identified lack of self-efficacy as a significant obstacle to introducing new work-based learning. In contrast, responders with ATLS training noted a lack of R-ETC colleagues as the main impediment for moving from conceptualisation to experimentation in the workplace. Conclusions Participation in the R-ETC led to behavioural changes in the workplace. However, the ability to influence others and bring about wider organizational changes was more difficult to achieve. Major factors were the status of the person, their experience and self-efficacy. National organizational impact was obtained which went far beyond our aspirations in acknowledging change in individual daily practice.

Although Mars does not possess a magnetic field today, parts of its crust are strongly magnetized, suggesting a limited early dynamo, likely powered by rapid heat flow from the core. If the core is...

The essential data for interior and thermal evolution models of the Earth and super-Earths are the density and melting of mantle silicate under extreme conditions. Here, we report an unprecedently high melting temperature of MgSiO3 at 500 GPa by direct shockwave loading of pre-synthesized dense MgSiO3 (bridgmanite) using the Z Pulsed Power Facility. We also present the first high-precision density data of crystalline MgSiO3 to 422 GPa and 7200 K and of silicate melt to 1254 GPa. The experimental density measurements support our density functional theory based molecular dynamics calculations, providing benchmarks for theoretical calculations under extreme conditions. The excellent agreement between experiment and theory provides a reliable reference density profile for super-Earth mantles. Furthermore, the observed upper bound of melting temperature, 9430 K at 500 GPa, provides a critical constraint on the accretion energy required to melt the mantle and the prospect of driving a dynamo in massive rocky planets. The authors here report high melting temperatures of MgSiO3 at 500 GPa by direct shockwave loading of pre-synthesized dense bridgemanite. This is essential data to understand the thermal evolution of the interiors of terrestrial (exo-)planets.

The essential data for interior and thermal evolution models of the Earth and super-Earths are the density and melting of mantle silicate under extreme conditions. Here, we report an unprecedently high melting temperature of MgSiO3 at 500 GPa by direct shockwave loading of pre-synthesized dense MgSiO3 (bridgmanite) using the Z Pulsed Power Facility. We also present the first high-precision density data of crystalline MgSiO3 to 422 GPa and 7200 K and of silicate melt to 1254 GPa. The experimental density measurements support our density functional theory based molecular dynamics calculations, providing benchmarks for theoretical calculations under extreme conditions. The excellent agreement between experiment and theory provides a reliable reference density profile for super-Earth mantles. Furthermore, the observed upper bound of melting temperature, 9430 K at 500 GPa, provides a critical constraint on the accretion energy required to melt the mantle and the prospect of driving a dynamo in massive rocky planets., The authors here report high melting temperatures of MgSiO3 at 500 GPa by direct shockwave loading of pre-synthesized dense bridgemanite. This is essential data to understand the thermal evolution of the interiors of terrestrial (exo-)planets.

Efforts to identify habitable planets must look beyond atmospheres to planetary interiors

We describe a software package called VPLanet that simulates fundamental aspects of planetary system evolution over Gyr timescales, with a focus on investigating habitable worlds. In this initial release, eleven physics modules are included that model internal, atmospheric, rotational, orbital, stellar, and galactic processes. Many of these modules can be coupled simultaneously to simulate the evolution of terrestrial planets, gaseous planets, and stars. The code is validated by reproducing a selection of observations and past results. VPLanet is written in C and designed so that the user can choose the physics modules to apply to an individual object at runtime without recompiling, i.e., a single executable can simulate the diverse phenomena that are relevant to a wide range of planetary and stellar systems. This feature is enabled by matrices and vectors of function pointers that are dynamically allocated and populated based on user input. The speed and modularity of VPLanet enables large parameter sweeps and the versatility to add/remove physical phenomena to assess their importance. VPLanet is publicly available from a repository that contains extensive documentation, numerous examples, Python scripts for plotting and data management, and infrastructure for community input and future development., Comment: 75 pages, 34 figures, 10 tables, accepted to the Proceedings of the Astronomical Society of the Pacific. Source code, documentation, and examples available at https://github.com/VirtualPlanetaryLaboratory/vplanet

Thermal and compositional convection in Earth's core are thought to be the main power sources driving geodynamo. The viability and strength of thermally and compositionally-driven convection over Earth's history depend on the adiabatic heat flow across the core-mantle boundary (CMB) which is governed by the thermal conductivity of a constituent Fe-Ni-light element alloy at the pressure-temperature (P-T) conditions relevant to the core. Silicon is often proposed to be an abundant light element alloyed with Fe along with ∼5 wt% Ni, but the thermal transport properties of Fe-Ni-Si alloys at high P-T remain largely uncertain. Here we measured the electrical resistivities of Fe-10wt%Ni and Fe-1.8wt%Si alloys up to ∼142 GPa and ∼3400 K using four-probe van der Pauw method in laser-heated diamond anvil cell experiments. Our results show that the resistivities of hcp-Fe-1.8Si and Fe-10Ni display quasi-linear temperature dependence from ∼1500 to 3400 K at each given high pressure. Addition of ∼2 wt% Si in hcp-Fe significantly increases its resistivity by ∼25% at ∼138 GPa and 4000 K, but Fe-10wt%Ni has similar resistivity to pure hcp-Fe at near CMB P-T conditions. Using our measured values of electrical resistivities, we model thermal conductivities via the Wiedemann-Franz law, giving a nominal thermal conductivity of ∼50 W m−1 K−1 for liquid Fe-5Ni-8Si alloy at the topmost outer core, implying an adiabatic (conductive) core heat flow of ∼8.0 TW. The outer core has a much lower thermal conductivity than the inner core due to light-element differentiation across the solidifying inner-core boundary. Our studies imply that the adiabatic core heat flow is low enough to enable thermal convection to drive the geodynamo over most and possibly all of Earth's history, while the strength of compositional convection increases with the inner-core growth and accounts for ∼83% of the buoyancy flux to the present-day geodynamo.

In the past three decades, mass casualty incidents have occurred worldwide at multiple sporting events and other mass gatherings. Organisational safety and healthcare provision can consequently be scrutinised post-event. Within the UK, such incidents in the 1980s provided incentives to improve medical services and subsequent high profile UK-based international sporting events (London Olympics and Paralympics 2012, Glasgow Commonwealth Games 2014, Rugby World Cup 2015) added a further catalyst for developing services. Furthermore in the aftermath of the abandoned France versus Germany association football match at the Stade de France (Paris Terrorist Attacks, November 2015) and the 2016 UK report from HM Coroner on the Hillsborough Inquest, medical cover at sporting events is being further reviewed. Doctors providing spectator cover therefore need to have an awareness of their likely roles at sporting venues. Formal guidance exists in many countries for the provision of such cover but remains generic even though Events Medicine is increasingly recognised as a necessary service. The current evidence base is limited with best practice examples often anecdotally cited by acute care specialists (eg, emergency medicine) who provide cover. This article is therefore intended to present an overview for doctors of the knowledge and skills required to treat ill and injured spectators and enable them to adequately risk-assess venues in cooperation with other health and safety providers, including preparation for a major incident. It also gives guidance on how activity can be adequately assessed and how doctors can have management roles in Events Medicine.

The paleomagnetic record indicates the geodynamo has been active over much of Earth history with surprisingly little trend in paleointensity. Variability, however, is expected from models that predict a sharp increase in intensity following inner core nucleation (ICN) and implied by Neoproterozoic anomalies that hint at a highly variable field over several hundred million years. Here we demonstrate with a suite of numerical dynamos driven by a new thermal evolution model that the geodynamo could have transitioned from a multipolar to dipolar regime around 1.7 Ga, then to a weak-field dynamo around 1.0 Ga, and finally to a strong-field dipole following ICN around 650 Ma that is maintained to the present day. The occurrence of a weak-field geodynamo in the Neoproterozoic may be consistent with the observed anomalous apparent polar wander paths and reversal behavior. Recovery to a dipolar geodynamo in the Phanerozoic could be a signature of inner core nucleation. Index terms: 1507, 1560, and 1521.

Long-term geodynamo evolution is expected to respond to inner core growth and changing patterns of mantle convection. Three geomagnetic superchrons, during which Earth's magnetic field maintained a near-constant polarity state through tens of Myr, are known from the bio/magnetostratigraphic record of Phanerozoic time, perhaps timed according to supercontinental episodicity. Some geodynamo simulations incorporating a much smaller inner core, as would have characterized Proterozoic time, produce field reversals at a much lower rate. Here we compile polarity ratios of site means within a quality-filtered global Proterozoic paleomagnetic database, according to recent plate kinematic models. Various smoothing parameters, optimized to successfully identify the known Phanerozoic superchrons, indicate 3–10 possible Proterozoic superchrons during the 1300 Myr interval studied. Proterozoic geodynamo evolution thus appears to indicate a relatively narrow range of reversal behavior through the last two billion years, implying either remarkable stability of core dynamics over this time or insensitivity of reversal rate to core evolution.

The proposal that the seismically observed hemispherical asymmetry of Earth's inner core is controlled by the heat flux structure imposed on the outer core by the lower mantle is tested with numerical dynamo models driven by mixed thermochemical convection. We find that models driven by a single core-mantle boundary (CMB) spherical harmonic of degree and mode 2, the dominant mode in lower mantle seismic shear velocity tomography, produce a similar structure at the inner core boundary (ICB) shifted 30∘ westward. The sensitivity of the ICB to the CMB is further tested by increasing the CMB heterogeneity amplitude. In addition, two seismic tomographic models are tested: first with CMB resolution up to degree and order 4, and second with resolution up to degree and order 8. We find time-averaged ICB heat flux in these cases to be similar at large scale, with small-scale differences due to higher CMB harmonics (above degree 4). The tomographic models produce “Earth-like” magnetic fields, while similar models with twice the CMB heat flow amplitudes produce less Earth-like fields, implying that increasing CMB heterogeneity forces the model out of an Earth-like regime. The dynamic ICB heat fluxes are compared to the proposed translation mode of the inner core to test whether the CMB controls inner core growth and structure. This test indicates that, although CMB tomography is unlikely to be driving inner core translation, the ICB heat flux response is weak enough to not interfere with the most unstable translation mode, if it is occurring.

The origin of Earth's ancient magnetic field is an outstanding problem. It has recently been proposed that exsolution of MgO from the core may provide sufficient energy to drive an early geodynamo. Here we present new experiments on Mg partitioning between iron-rich liquids and silicate/oxide melts. Our results indicate that Mg partitioning depends strongly on the oxygen content in the iron-rich liquid, in contrast to previous findings that it depends only on temperature. Consequently, MgO exsolution during core cooling is drastically reduced and insufficient to drive an early geodynamo alone. Using the new experimental data, our thermal model predicts inner core nucleation at ~850 Ma and a nearly constant paleointensity.

The study of the thermal evolution of Earth’s interior is uncertain and controversial in many respects, from the interpretation of petrologic observations used to infer the temperature and dynamics of the interior, to the physics and material properties governing heat transport. The thermal history of Venus is even more uncertain, but the lack of a dynamo at present in an otherwise similar planet may provide additional constraints on terrestrial planet evolution. In this paper a one dimensional thermal history model is derived that includes heat loss due to mantle melt eruption at the surface to explore its influence on the thermal and magnetic history of Earth and Venus. We show that the thermal catastrophe of Earth’s mantle, which occurs for a present day Urey ratio of 1/3 and convective heat loss exponent of β = 1 / 3 , can be avoided by assuming a rather high core heat flow of ∼15 TW. This core heat flow also avoids the new core paradox by allowing for the geodynamo to be thermally powered prior to inner core growth for core thermal conductivities as high as 130 Wm - 1 K - 1 . Dynamo regime diagrams demonstrate that the mantle melt eruption rate has a minor effect on the history of mobile lid planets due to the efficiency of plate tectonic convective heat loss. However, if Earth were in a stagnant lid regime prior to 2.5 Ga, as has been proposed, then at least ∼5% of mantle melt is required to erupt in order to thermally power the paleodynamo at that time. Dynamo regime diagrams for stagnant lid Venus models indicate that more than half of the melt generated in the mantle is required to erupt in order to overcome the insulation imposed by the stagnant lid and drive a dynamo. This implies that with an Earth-like mantle radioactivity the Venusian dynamo shut down ∼0.3 Ga for an eruption efficiency of 50 % , and ∼3 Ga for an eruption efficiency of zero. Consequently, a stagnant lid alone does not prevent a core dynamo if melting of the upper mantle provides a substantial mantle heat sink.

Shermanʼs ω -test applied to the Geomagnetic Polarity Time Scale (GPTS) reveals that geomagnetic reversals in the Phanerozoic deviate substantially from random times. For 954 Phanerozoic reversals, ω exceeds the value expected for uniformly distributed random times by many standard deviations, due to three constant polarity superchrons and clustering of reversals in the Cenozoic C-sequence. Reversals are nearly periodic in several portions of the Mesozoic M-sequence, and during these times ω falls below random by several standard deviations, according to some chronologies. Polarity reversals in a convection-driven numerical dynamo with fixed control parameters have an overall ω -value that is slightly lower than uniformly random due to weak periodicity, whereas in a numerical dynamo with time-variable control parameters the combination of superchrons and reversal clusters dominates, yielding a large ω -value that is comparable to the GPTS. Shermanʼs test applied to shorter Phanerozoic reversal sequences reveals two geodynamo time scales: hundreds of millions of years represented by superchrons and reversal clusters that we attribute to time-dependent core–mantle thermal interaction, plus unexplained variations lasting tens of millions of years characterized by alternation between random and nearly periodic reversals.

Knowledge of the earliest evolution of Earth and Venus is extremely limited, but it is obvious from their dramatic contrasts today that at some point in their evolution conditions on the two planets diverged. In this paper we develop a geophysical systems box model that simulates the flux of carbon through the mantle, atmosphere, ocean, and seafloor, and the degassing of water from the mantle. Volatile fluxes, including loss to space, are functions of local volatile concentration, degassing efficiency, tectonic plate speed, and magnetic field intensity. Numerical results are presented that demonstrate the equilibration to a steady state carbon cycle, where carbon and water are distributed among mantle, atmosphere, ocean, and crustal reservoirs, similar to present-day Earth. These stable models reach steady state after several hundred million years by maintaining a negative feedback between atmospheric temperature, carbon dioxide weathering, and surface tectonics. At the orbit of Venus, an otherwise similar model evolves to a runaway greenhouse with all volatiles in the atmosphere. The influence of magnetic field intensity on atmospheric escape is demonstrated in Venus models where either a strong magnetic field helps the atmosphere to retain about 60 bars of water vapor after 4.5 Gyr, or the lack of a magnetic field allows for the loss of all atmospheric water to space in about 1 Gyr. The relative influences of plate speed and degassing rate on the weathering rate and greenhouse stability are demonstrated, and a stable to runaway regime diagram is presented. In conclusion, we propose that a stable climate-tectonic-carbon cycle is part of a larger coupled geophysical system where a moderate surface climate provides a stabilizing feedback for maintaining surface tectonics, the thermal cooling of the deep interior, magnetic field generation, and the shielding of the atmosphere over billion year time scales.

We build a broadband frequency spectrum for geomagnetic dipole intensity variations originating in the core using results from numerical dynamos. Scaling dipole intensity spectra from numerical dynamos with diverse input parameters (Ekman, Rayleigh, and magnetic Prandtl numbers) and magnetic Reynolds numbers from 170 to 1985 yields a composite spectrum ranging from ultra-low frequencies (∼ 100 Myr period) to very high frequencies (∼ 1 yr period). The amplitude and shape of our composite spectrum compare favorably with estimates of the geomagnetic and paleomagnetic dipole moment spectra. Significant power is found in an ultra-low frequency band f 2 kyr− 1, representing archaeomagnetic and historical geomagnetic secular variation, we find n ≃ 4 on average, with spectral slope increasing at very high frequencies to near n ≃ 6 at f = 1 yr− 1. The secular variation and the secular acceleration spectra for the dipole field reach their peak values in the high frequency band, close to frequencies where spectra for the dynamo fluid velocity decrease sharply.

A potentially promising way to gain knowledge about the internal dynamics of extrasolar planets is by remote measurement of an intrinsic magnetic field. Strong planetary magnetic fields, maintained by internal dynamo action in an electrically conducting fluid layer, are helpful for shielding the upper atmosphere from stellar wind induced mass loss and retaining water over long (Gyr) time scales. Here we present a whole planet dynamo model that consists of three main components: an internal structure model with composition and layers similar to the Earth, an optimal mantle convection model that is designed to maximize the heat flow available to drive convective dynamo action in the core, and a scaling law to estimate the magnetic field intensity at the surface of a terrestrial exoplanet. We find that the magnetic field intensity at the core surface can be up to twice the present-day geomagnetic field intensity, while the magnetic moment varies by a factor of 20 over the models considered. Assuming electron cyclotron emission is produced from the interaction between the stellar wind and the exoplanet magnetic field we estimate the cyclotron frequencies around the ionospheric cutoff at 10 MHz with emission fluxes in the range 10 −4 –10 −7 Jy, below the current detection threshold of radio telescopes. However, we propose that anomalous boosts and modulations to the magnetic field intensity and cyclotron emission may allow for their detection in the future.

We analyze more than two hundred and forty magnetic polarity reversals and excursions over forty million years of time from numerical dynamos with heterogeneous boundary heat flux. Comparisons between a dynamo with uniform boundary heat flux, dynamos with boundary heat flux patterns consisting of a single spherical harmonic, and dynamos with tomographic heat flux patterns proportional to the large-scale lateral variation of seismic shear wave velocity in the lower mantle reveal that boundary heat flux heterogeneity tends to increase the average frequency of polarity reversals relative to uniform boundary conditions, particularly if the heterogeneity increases the average equatorial heat flux. Non-axisymmetric spherical harmonic degree l = 1 and 2 boundary heterogeneity and the seismically derived tomographic heterogeneity produce comparable reversal and excursion frequencies in our models, suggesting that geomagnetic polarity reversal rates may be relatively insensitive to the non-axisymmetric planform of core–mantle boundary heat flux. In contrast, the average polarity reversal frequency in our models is quite sensitive to the total boundary heat flow and to the total heat flow at the equator, with non-reversing behavior at low heat flow and frequent reversals at high heat flow conditions. Reversal frequency also increases with the amplitude of the boundary heterogeneity, although it is less sensitive to this parameter. Our results suggest that geomagnetic superchrons may correspond to times with reduced core–mantle boundary heat flow, either globally or equatorially, and conversely, periods with high paleomagnetic reversal frequency may correspond to times with increased heat flow at the core–mantle boundary.

SUMMARY We present the results of 50 simulations of the geodynamo using a gravitational dynamo model driven by compositional convection in an electrically conducting 3-D fluid shell. By varying the relative strengths of buoyancy and rotation these simulations span a range of dynamo behaviour from strongly dipolar, non-reversing to multipolar and frequently reversing. The polarity reversal frequency is increased with increasing Rayleigh number and Ekman number. Model behaviour also varies in terms of dipolarity, variability of the dipole, and core–mantle boundary field spectra. A transition region is found where the models have dipolar fields and moderate (Earth-like) reversal frequencies of approximately 4 per Myr. Dynamo scaling laws are used to compare model dipole intensities to the geodynamo. If the geodynamo lies in a similar transition region then secular evolution of the buoyancy flux in the outer core due to the growth of the inner core and the decrease in the Earth’s rotation rate due to tidal dissipation can account for some of the secular changes in the reversal frequency and other geomagnetic field properties over the past 100 Myr.

Numerical dynamos with time-variable control parameters that simulate the secular evolution of the core are used to interpret long-term trends in geomagnetic field behavior, including polarity reversal frequency. Dynamos with incremental changes in convective forcing and rotation rate show continuous trends in dipole field intensity and fluid velocity, with systematic variations in polarity chrons in some cases. Otherwise similar dynamos with constant forcing and rotation rate have statistically stationary dipole field intensity and fluid velocity, with random polarity chrons. A reversing dynamo with steady rotational deceleration constrained by tidal friction and a decreasing (regular) inner core growth rate constrained by core thermal history evolves over 10 Myr with minor trends in average dipole intensity, fluid velocity, and polarity chron length. In contrast, a dynamo started in a non-reversing state and subject to an increasing (anomalous) inner core growth rate and constant rotation evolves over 20 Myr to a reversing state with substantial trends in dipole intensity and polarity chron length. The dispersion of polarity chron lengths in the dynamo model with anomalous evolution is qualitatively similar to the observed dispersion of geomagnetic polarity chrons since the end of the Cretaceous Normal Superchron, and the model dipole field frequency spectra are qualitatively similar to estimates of the geomagnetic spectrum at very low frequencies.

We report the detection of five Jovian mass planets orbiting high metallicity stars. Four of these stars were first observed as part of the N2K program and exhibited low RMS velocity scatter after three consecutive observations. However, follow-up observations over the last three years now reveal the presence of longer period planets with orbital periods ranging from 21 days to a few years. HD 11506 is a G0V star with a planet of \msini = 4.74 \mjup in a 3.85 year orbit. HD 17156 is a G0V star with a 3.12 \mjup planet in a 21.2 day orbit. The eccentricity of this orbit is 0.67, one of the highest known for a planet with a relatively short period. The orbital period for this planet places it in a region of parameter space where relatively few planets have been detected. HD 125612 is a G3V star with a planet of \msini = 3.5 \mjup in a 1.4 year orbit. HD 170469 is a G5IV star with a planet of \msini = 0.67 \mjup in a 3.13 year orbit. HD 231701 is an F8V star with planet of 1.08 \mjup in a 142 day orbit. All of these stars have supersolar metallicity. Three of the five stars were observed photometrically but showed no evidence of brightness variability. A transit search conducted for HD 17156 was negative but covered only 25% of the search space and so is not conclusive., Comment: 13 pages, 9 figures, accepted ApJ Resubmitted here with some additional data, modified Keplerian orbits

We report precision Doppler measurements of three intermediate-mass subgiants from Lick and Keck Observatories. All three stars show variability in their radial velocities consistent with planet-mass companions in Keplerian orbits. We find a planet with a minimum mass of 2.5 Mjup in a 351.5 day orbit around HD 192699, a planet with a minimum mass of 2.0 Mjup in a 341.1 day orbit around HD 210702, and a planet with a minimum mass of 0.61 Mjup in a 297.3 day orbit around HD 175541. Stellar mass estimates from evolutionary models indicate that all of these stars were formerly A-type dwarfs with masses ranging from 1.65 to 1.85 Msun. These three long-period planets would not have been detectable during their stars' main-sequence phases due to the large rotational velocities and stellar jitter exhibited by early-type dwarfs. There are now 9 "retired" (evolved) A-type stars (Mstar > 1.6 Msun) with known planets. All 9 planets orbit at distances a \geq 0.78 AU, which is significantly different than the semimajor axis distribution of planets around lower-mass stars. We examine the possibility that the observed lack of close-in planets is due to engulfment by their expanding host stars, but we find that this explanation is inadequate given the relatively small stellar radii of K giants (Rstar < 32 Rsun = 0.15 AU) and subgiants (Rstar < 7 Rsun = 0.03 AU). Instead, we conclude that planets around intermediate-mass stars reside preferentially beyond ~0.8 AU, which may be a reflection of different formation and migration histories of planets around A-type stars., 31 pages, 9 figures, 6 tables, ApJ accepted, corrected minor typos

The internal thermal and magnetic evolution of rocky exoplanets is critical to their habitability. We focus on the thermal-orbital evolution of Earth-mass planets around low mass M stars whose radiative habitable zone overlaps with the "tidal zone". We develop a thermal-orbital evolution model calibrated to Earth that couples tidal dissipation, with a temperature-dependent Maxwell rheology, to orbital circularization and migration. We illustrate thermal-orbital steady states where surface heat flow is balanced by tidal dissipation and cooling can be stalled for billions of years until circularization occurs. Orbital energy dissipated as tidal heat in the interior drives both inward migration and circularization, with a circularization time that is inversely proportional to the dissipation rate. We identify a peak in the internal dissipation rate as the mantle passes through a visco-elastic state at mantle temperatures near 1800 K. Planets orbiting a 0.1 solar-mass star within $0.07$ AU circularize before 10 Gyr, independent of initial eccentricity. Once circular, these planets cool monotonically and maintain dynamos similar to Earth. Planets forced into eccentric orbits can experience a super-cooling of the core and rapid core solidification, inhibiting dynamo action for planets in the habitable zone. We find that tidal heating is insignificant in the habitable zone around $0.45$ (or larger) solar mass stars because tidal dissipation is a stronger function of orbital distance than stellar mass, and the habitable zone is further from larger stars. Suppression of the planetary magnetic field exposes the atmosphere to stellar wind erosion and the surface to harmful radiation. In addition to weak magnetic fields, massive melt eruption rates and prolonged magma oceans may render eccentric planets in the habitable zone of low mass stars inhospitable for life., Comment: 16 figures, 1 table, appendix with 2 figures

The N2K ("next 2000") consortium is carrying out a distributed observing campaign with the Keck, Magellan, and Subaru telescopes, as well as the automatic photometric telescopes of Fairborn Observatory, in order to search for short-period gas giant planets around metal-rich stars. We have established a reservoir of more than 14,000 main-sequence and subgiant stars closer than 110 pc, brighter than V = 10.5, and with 0.4 < B - V < 1.2. Because the fraction of stars with planets is a sensitive function of stellar metallicity, a broadband photometric calibration has been developed to identify a subset of 2000 stars with [Fe/H] > 0.1 dex for this survey. We outline the strategy and report the detection of a planet orbiting the metal-rich G5 IV star HD 88133 with a period of 3.41 days, semivelocity amplitude K = 35.7 m s^(-1), and M sin i = 0.29M_J. Photometric observations reveal that HD 88133 is constant on the 3.415 day radial velocity period to a limit of 0.0005 mag. Despite a transit probability of 19.5%, our photometry rules out the shallow transits predicted by the large stellar radius.

Inter-individual differences in neuroendocrine and behavioural responses to environmental challenges will be considered within the context of psychogenetic selection, using the Roman High-(RHA) and Low-(RLA) Avoidance rat lines as an example. We assume that the selected genotypes, by interacting with environmental factors, determine specific 'biobehavioural profiles'. Practical and theoretical problems regarding the measurement of inter-individual vs line/strain differences, the definition of 'traits' vs experimental variables, and possible correlations between physiological and behavioural parameters will be discussed. We will argue that environmental influences are the main cause of inter-individual variability, and that the genotype only constitutes a 'blueprint' from which typical biobehavioural profiles are established, notably under the influence of early environmental factors. These biobehavioural profiles may correspond in part to human categories known as 'types', 'temperaments' or 'personality traits'. Within each category (including those which can be obtained by psychogenetic selection), more individual personality traits can evolve, notably as a result of social interactions and particular life events.

The mesolimbic dopamine system is considered to play a pivotal role in the locomotor activation produced by psychostimulants and in the augmentation of this effect observed upon repeated drug administration, a process denominated behavioral sensitization. The selective breeding of Roman high- (RHA) and low-avoidance (RLA) rats, respectively, for rapid versus poor active avoidance acquisition has resulted in two phenotypes that differ in the functional properties of the mesolimbic dopamine system and in their behavioral and neurochemical responses to addictive drugs, including psychostimulants and opiates. Hence, the present study was designed to compare the ability of these lines to develop behavioral sensitization to psychostimulants. To this aim, the acute effects of amphetamine (0.125 or 0.25 mg/kg, s.c.) on locomotion were assessed in RHA and RLA rats prior to and subsequent to 10 daily doses of either amphetamine (1 mg/kg, s.c.) or saline (1 ml/kg, s.c.). In the RHA line, the locomotor activation produced by either challenge dose of amphetamine was more pronounced in rats that had been repeatedly treated with amphetamine versus the respective saline treated controls. In contrast, no significant change in locomotor activity was observed in RLA rats. Likewise, repeated amphetamine caused an increased frequency of sniffing, rearing, licking/gnawing, and grooming versus the control, repeated saline, group only in the RHA line. The results show that the repeated treatment regimen used in this study induced behavioral sensitization to amphetamine in RHA rats, but not in their RLA counterparts, and underscore the utility of these lines for studying the influence of neural substrates and genetic make up on the individual vulnerability to addiction.

Editor's Note: To encourage attention to medical errors in psychiatry, Psychiatric Services introduced the Patient Safety Forum in December 2003. Expert discussants are invited to address important questions in this area. Benjamin Grasso, M.D., is guest editor of the forum. Contributing to this month's forum are Virginia Green, a mental health care consumer; Carol Carothers, executive director of NAMI Maine, and Peter Driscoll, M.S.W., director of Amistad, Maine's largest peer support and recovery center; Dollie Hunt-Wilson, another consumer; and Christine Siegfried, M.S.S.W., and Jenifer Wood, Ph.D., of the National Center for Child Traumatic Stress.

Addictive substances like morphine and psychostimulants induce a preferential increase in dopamine (DA) output in the nucleus accumbens (NAC), a major terminal field of the mesolimbic dopaminergic projection. Two subregions of the NAC, the dorsolateral core and the ventromedial shell, are thought to subserve different functions related to the reinforcing properties of natural and drug rewards. The selective breeding of Roman high- (RHA) and low-avoidance (RLA) rats, respectively, for rapid vs. extremely poor active avoidance acquisition in a shuttle-box has resulted in two phenotypes that differ in their behavioural and neurochemical responses to addictive drugs. We used brain dialysis to assess whether such differences in the responsiveness to drugs of abuse are related to differences in mesolimbic DA neuron function. In RHA rats, morphine, cocaine, and amphetamine caused a larger increase in DA efflux in the NAC shell vs. the NAC core, whereas the profile for the drug-induced increases in DA output was almost completely superimposable in the NAC shell and NAC core of RLA rats. Moreover, morphine, cocaine, and amphetamine caused a larger increment in basal DA output in the NAC shell of RHA rats vs. the NAC shell of RLA rats. These drugs also elicited a more robust increase in locomotion, rearing, sniffing, and grooming in RHA than in RLA rats. These results demonstrate that genetically determined differences in the functional properties of DA neurons projecting to the NAC shell may critically influence the behavioural response patterns to addictive drugs that distinguish the Roman lines.

The selective breeding of Roman high- (RHA/Verh) and low-avoidance (RLA/Verh) rats for rapid versus poor acquisition of active avoidant behaviour has produced two behavioural phenotypes with different performances in a variety of animal models of anxiety, in which RLA/Verh rats are consistently more fearful than RHA/Verh rats. In addition, these two lines display different functional properties of brain neurotransmitters like serotonin (5-HT), known to be involved in the expression of anxiety- and depression-related behaviours. Therefore, we used brain microdialysis and [3H]-citalopram binding autoradiography to characterize further the neurochemical properties of 5-HTergic transmission in the two lines. No significant line-related differences were detected in the basal 5-HT output in the frontoparietal cortex (FPCx). In contrast, the increase in the cortical 5-HT output elicited by the systemic administration or the local application, via reverse dialysis, of chlorimipramine and fluoxetine was more robust in RHA/Verh than in RLA/Verh rats. Moreover, the binding signal of [3H]-citalopram to 5-HT re-uptake sites was more intense in the FPCx of RHA/Verh rats than in their RLA/Verh counterparts. These findings suggest that the functional tone of the 5-HTergic projection to the FPCx is stronger in the RHA/Verh line relative to the RLA/Verh line. It is proposed that RLA/Verh rats may be used as a model with heuristic value for studying the role of 5-HTergic transmission in anxiety and in the anxiolytic effects of monoamine re-uptake inhibitors.

This experiment studied the effect of phone conversations and other potential interference on reaction time (RT) in a braking response. Using a laboratory station which simulated the foot activity in driving, 22 research participants were requested to release the accelerator pedal and depress the brake pedal as quickly as possible following the activation of a red brake lamp. Mean reaction time was determined for five conditions: (a) control, (b) listening to a radio, (c) conversing with a passenger, (d) conversing using a hand-held phone, and (e) conversing using a hands-free phone. Results indicated that conversation, whether conducted in-person or via a cellular phone caused RT to slow, whereas listening to music on the radio did not.

The mesocortical and mesolimbic dopaminergic (DAergic) pathways are activated by either aversive or rewarding stimuli. The functional tone of these DAergic neurons also increases during the execution of cognitive tasks. The present study was designed to examine the relationship between mesocortical and mesolimbic DAergic function and the expression of fear-related behaviours as compared with attention- and cognition-related mechanisms (e.g. coping strategies), in response to aversive conditions. To this aim, we used two psychogenetically selected rat lines, Roman high-avoidance (RHA/Verh) and Roman low-avoidance (RLA/Verh), which display drastically different emotion- and coping-related behaviours in response to stressors: RLA/Verh rats are 'reactive copers' and more fearful than RHA/Verh rats, which are 'proactive copers'. Brain dialysis experiments demonstrated that tail-pinch (TP) and the anxiogenic compounds pentylenetetrazol (PTZ) and ZK 93426 increased DA output in the medial prefrontal cortex (PFCX) of RHA/Verh but not RLA/Verh, rats. In contrast, in the shell compartment of the nucleus accumbens (NAC shell), TP caused a small increase in DA output only in RLA/Verh rats, whereas PTZ and ZK 93426 had no significant effect on either line. RHA/Verh rats displayed more robust and longer lasting coping activity and less frequent freezing and self-grooming episodes than did RLA/Verh rats after TP, PTZ or ZK 93426. This dissociation between fear-related behaviour and cortical DAergic activation argues against the view that the latter may be involved in the control of fear-like responses. We therefore propose that the activation of mesocortical DAergic projections by aversive stimuli underlies the cognitive mechanisms that are triggered in an attempt to gain control over the stressor.

Rationale: One of the major pathways for neurotransmitter signaling involves phosphoinositide-specific and G-protein-dependent phospholipase C-β (PLC-β), which stimulates the formation of inositol 1,4,5-trisphosphate and diacylglycerol. Serotonergic and muscarinic-cholinergic signals in the brain are largely mediated through the hydrolysis of phosphoinositides by PLC. Objectives: The aim of the experiments reported here was to explore the potential differences in neurotransmitter receptor coupling to PLC in Roman high-avoidance (RHA)/Verh and Roman low-avoidance (RLA)/Verh rats, by examining the changes in agonist (carbachol, 5-methyltryptamine)-stimulated phosphoinositide hydrolysis in hippocampal and cortical membranes derived from the two rat lines. Methods: To investigate changes in receptor and G-protein coupling to PLC in the brains of these two psychogenetically selected rat lines, which differ in their emotional profiles/learning abilities, we examined GTPγS-, agonist (carbachol, 5-methyltryptamine)-, and calcium-stimulated phosphoinositide hydrolysis in cortical and hippocampal membranes of RHA/Verh and RLA/Verh rats. Results: The results indicated that calcium-induced increase in PLC activity was larger in the cortex and hippocampus of RHA/Ver rats, as compared to their RLA/Verh counterparts. Conversely, GTPγS- and agonist-induced PLC activity was less pronounced in the hippocampus of RHA/Verh with respect to RLA/Verh rats. Western blot analysis showed no significant differences in the relative values of the G-proteins αq/11 and βγ subunits between both groups of rats in any brain region. However, the levels of PLC-β1, PLC-β3, and PLC-β4 were significantly lower in the hippocampus of RHA/Verh than in RLA/Verh rats. Conclusions: It is concluded that the hippocampus of RHA/Verh rats has severe deficiencies in PLC activity stimulated by guanine nucleotides and agonists, which are specifically related to a lower level of expression of the PLC-β type isozymes, a fact that may account for the differential behavioral phenotype observed in these psychogenetically selected rat lines.

Trauma is a diverse disease in which time critical decisions and skills affect patient outcome. This review article examines the methods and assessment of education for the management of the trauma patient.Literature review.Education is a planned experience that leads to a change in behaviour. Adult education methods can be used to improve the knowledge, skills, attitudes and relationships of health care workers. Adult learners need careful consideration of lecture style, small group work, role play and skills stations in order to achieve these aims. These techniques are typically used in short intensive courses such as Advanced Trauma Life Support (ATLS) aimed at the initial care of the trauma patient. There is a relative lack of education directed at definitive care. It is important to assess the impact of trauma education in terms of clinical process, retention of skills/knowledge and the outcome of patients. A generic approach (the ABC approach) is applicable to the care of all critically ill or injured patients. This approach should be taught at junior level.The care of trauma patients can be improved by educating health care workers using adult educational strategies.

In the present study, male inbred animals (from the 10th generation of an inbreeding program that has been carried out in parallel to that of the outbred Roman high- and low-avoidance rat lines), were compared for emotionality in different testing situations, exploratory behavior in the holeboard and two-way, active-avoidance acquisition. Compared to the inbred Roman high-avoidance (RHA-I/Verh) rats, inbred Roman low-avoidance (RLA-I-Verh) rats showed higher emotionality in the open field (reduced distance travelled and number of rearings, and increased self-grooming behavior), in the elevated plus-maze test (increased number of total and open-arm entries, reduced distance travelled in the open arms, and increased self-grooming behavior), and during the habituation period in the shuttle box (decreased number of crossings, increased self-grooming behavior and defecations). Results from the hyponeophagia test were not conclusive, probably due to the test-dependent hyperactivity shown by RHA-I/Verh rats. In the holeboard apparatus, RHA-I/Verh rats explored more than RLA-I/Verh rats, especially when novel objects were located beneath the holes. Finally, RHA-I/Verh animals rapidly acquired active, two-way (shuttlebox) avoidance, whereas RLA-I/Verh animals required four 50-trial sessions to achieve an assymptotic level of 30-40% avoidance. Thus, the behavioral patterns of the Roman inbred strains were very similar to those previously reported for the RHA/Verh outbred lines. Differences in locomotor activity, exploratory, and self-grooming behavior were actually greater between the inbred strains than between the outbred lines. Differences in defecation, however, although still significant, were not so pronounced as those noted previously at this laboratory with the outbred lines.

The pharmacological properties of benzodiazepine binding sites of the gamma-aminobutyric acid (GABA)A receptor complex from cortical, hippocampal and cerebellar membranes of Roman high-avoidance (RHA/Verh) and Roman low-avoidance (RLH/Verh) rats were investigated. No major differences between the two lines were found in the binding parameters of [3H]flunitrazepam (a non-selective agonist). [3 H]zolpidem (a Type I selective agonist) or [3 H]ethyl 8-azido-6-dihydro-5-methyl-6-oxo-4H-imidazol[1,5-a]-[1,4]benzodiazepine- 3-carboxylate (Ro15-4513) (a partial inverse agonist). Neither the Kd values nor the Bmax for these ligands differed between RHA/Verh and RLA/Verh rats in any of the brain regions studied. As a result, the proportion of Type I binding sites in cortical and hippocampal membranes of RHA/Verh and RLA/Verh rats or the 'diazepam-sensitive' and the 'diazepam-insensitive' binding sites in cerebellar membranes, calculated from the [3H]flunitrazepam and [3H]zolpidem maximal binding sites or from [3H]Ro15-4513 binding (in the absence or in presence of diazepam), respectively, was also similar. Furthermore, there were no differences between the two rat lines in the allosteric interactions between GABA and the benzodiazepine binding sites (labeled with [3H]flunitrazepam) in all three areas tested or the Type I binding sites (labeled with [3H]zolpidem) in the hippocampus. In contrast, RLA/Verh rats showed a significant reduction in the allosteric interactions between GABA and [3H]zolpidem binding sites in the cortex. As a whole, these results indicate the absence of generalized between-line differences in the GABA(A) receptor complex showing, at the same time, the existence of some specific differences in allosterism within the GABA(A) complex. These differences may contribute to the divergent emotional responses which characterize the RHA/Verh and RLA/Verh rat lines.

Roman high-(RHA/Verh) and low-(RLA/Verh) avoidance rats, originally selected and bred for rapid vs poor acquisition of a two-way active avoidance response, differ in emotional reactivity and coping style. These differences are associated with particular neuroendocrine and neurochemical characteristics. New data are presented here to show that the behavioural changes specifically induced by neonatal handling, i.e. decreased emotional reactivity, are associated with marked changes in the neuroendocrine responses of (hyperemotional) RLA/Verh rats to a novel environment. Eight months after neonatal handling, self-grooming behaviour, a reliable marker of emotional reactivity in this line of rats, was significantly decreased in RLA/Verh rats. Defecation scores were also significantly reduced in both lines. Moreover, there was a significant reduction in prolactin and corticosterone release following exposure to a novel environment in neonatally-handled RLA/Verh rats as compared to control, non-handled rats. No effects on prolactin and corticosterone release were observed in RHA/Verh rats. There was also no apparent effect of neonatal handling on coping style i.e. RLA/Verh rats did not increase their spontaneous exploration of novel environments. Thus, the phenotypic expression of basic traits of (high) neuroendocrine/emotional reactivity was specifically modulated by neonatal handling in RLA/Verh rats, whereas both the (hypoemotional) RHA/Verh rats as well as coping style in both lines remained unaffected. Changes in emotional reactivity were still apparent at 12 months of age when rats from the same groups were tested for hyponeophagia. These results suggest that psychogenetically selected lines such as RHA/RLA rats are suitable animal models to investigate interactions between genes and the environment in determining individual sensitivity to stress and coping styles, as well as potential vulnerability (or resistance) to the development of maladaptive syndromes similar to anxiety and mood disorders in humans.

The effect of closely spaced stimulus pairs (S1–S2), one at or above threshold for eliciting the second electromyographic burst of the cutaneous blink reflex (R2) and one below threshold intensity, on the latency, duration, and area of R2 was examined in four experiments. The size of the R2 elicited by a threshold S1 (but not by an S1 at three times threshold intensity) was augmented by threshold or near-threshold S2s that appeared after stimulus onset asynchronies of 4, 8, and 16 msec. More intense S2s had a greater effect on R2 size and led also to a slight shortening of R2 latency. Although R2 augmentation was accompanied by a modest increase in response duration, this increase in duration was by itself insufficient to account for the augmentation of response amplitude. Subreflexogenic S1s (at 0.1, 0.2, 0.4, and 0.8 times R2 threshold intensity) did not affect the R2 elicited by an S2 at threshold intensity or two times threshold intensity. Unlike the simple brainstem pathway which mediates R1, the more complex brainstem pathway which mediates R2 is capable of summing stimulus energy over time.

Spontaneous eating patterns in male, inbred Roman high- and low-avoidance rats (RHA/Verh, RLA/Verh) were continuously recorded while animals were successively offered three isocaloric (≍16.5-kJ/g) diets: a low-fat, high-carbohydrate diet (LF; 3.3% fat), a medium-fat diet (MF; 18% fat), and a high-fat diet (HF; 40% fat), the latter being followed once again by the LF diet. Under the conditions of this experiment, overall 24h food intake did not differ significantly between RHA/Verh and RLA/Verh rats, but was significantly higher for both rat strains on the MF and HF diets than on the LF diet. Despite the similar 24h-food intake, RHA/Verh rats ate transiently less than RLA/Verh rats during the third quarter of the dark phase under all dietary conditions. These differences were due to the RHA/Verh rats' longer intermeal intervals (with all diets) and smaller meals (with the MF and HF diets) and were compensated for during the last 3 h of the dark phase. On the LF diet, dark-phase meal frequency was higher and both nocturnal meal size and mean eating rate within meals were lower in RLA/Verh rats than in RHA/Verh rats. With the MF and HF diets, mean nocturnal meal size and meal duration were higher and mean eating rate was lower in RLA/Verh rats than in RHA/Verh rats. For both strains, nocturnal meal size was significantly higher with the MF and HF diets than with the LF diet, and nocturnal meal frequency was lower with the HF diet than with the other two diets. Although body weights were similar at the start of the study, RLA/Verh rats gained significantly more weight than did RHA/Verh rats by the end. As has often been the case with other aspects of behavior studied, differences in neuromodulatory systems (e.g., serotoninergic and dopaminergic) between RHA/Verh and RLA/Verh rats may directly or indirectly contribute to the subtle differences in eating patterns observed here.