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This manuscript assess the current and expected future global drivers of Southern Ocean (SO) ecosystems. Atmospheric ozone depletion over the Antarctic since the 1970s, has been a key driver, resulting in springtime cooling of the stratosphere and intensification of the polar vortex, increasing the frequency of positive phases of the Southern Annular Mode (SAM). This increases warm air-flow over the East Pacific sector (Western Antarctic Peninsula) and cold air flow over the West Pacific sector. SAM as well as El Niño Southern Oscillation events also affect the Amundsen Sea Low leading to either positive or negative sea ice anomalies in the west and east Pacific sectors, respectively. This strengthening of westerly winds is also linked to shoaling of deep warmer water onto the continental shelves, particularly in the East Pacific and Atlantic sectors. Air and ocean warming has led to changes in the cryosphere, with glacial and ice sheet melting in both sectors, opening up new ice free areas to biological productivity, but increasing seafloor disturbance by icebergs. The increased melting is correlated with a salinity decrease particularly in the surface 100 m. Such processes could increase the availability of iron, which is currently limiting primary production over much of the SO. Increasing CO2 is one of the most important SO anthropogenic drivers and is likely to affect marine ecosystems in the coming decades. While levels of many pollutants are lower than elsewhere, persistent organic pollutants (POPs) and plastics have all been detected in the SO, with concentrations likely enhanced by migratory species. With increased marine traffic and weakening of ocean barriers the risk of the establishment of non-indigenous species is increased. The continued recovery of the ozone hole creates uncertainty over the reversal in sea ice trends, especially in the light of the abrupt transition from record high to record low Antarctic sea ice extent since spring 2016. The curre

This manuscript assess the current and expected future global drivers of Southern Ocean (SO) ecosystems. Atmospheric ozone depletion over the Antarctic since the 1970s, has been a key driver, resulting in springtime cooling of the stratosphere and intensification of the polar vortex, increasing the frequency of positive phases of the Southern Annular Mode (SAM). This increases warm air-flow over the East Pacific sector (Western Antarctic Peninsula) and cold air flow over the West Pacific sector. SAM as well as El Niño Southern Oscillation events also affect the Amundsen Sea Low leading to either positive or negative sea ice anomalies in the west and east Pacific sectors, respectively. This strengthening of westerly winds is also linked to shoaling of deep warmer water onto the continental shelves, particularly in the East Pacific and Atlantic sectors. Air and ocean warming has led to changes in the cryosphere, with glacial and ice sheet melting in both sectors, opening up new ice free areas to biological productivity, but increasing seafloor disturbance by icebergs. The increased melting is correlated with a salinity decrease particularly in the surface 100 m. Such processes could increase the availability of iron, which is currently limiting primary production over much of the SO. Increasing CO2 is one of the most important SO anthropogenic drivers and is likely to affect marine ecosystems in the coming decades. While levels of many pollutants are lower than elsewhere, persistent organic pollutants (POPs) and plastics have all been detected in the SO, with concentrations likely enhanced by migratory species. With increased marine traffic and weakening of ocean barriers the risk of the establishment of non-indigenous species is increased. The continued recovery of the ozone hole creates uncertainty over the reversal in sea ice trends, especially in the light of the abrupt transition from record high to record low Antarctic sea ice extent since spring 2016. The curre

Computational analysis has become ubiquitous within the heliophysics community. However, community standards for peer-review of codes and analysis have lagged behind these developments. This absence has contributed to the reproducibility crisis, where inadequate analysis descriptions and loss of scientific data have made scientific studies difficult or impossible to replicate. The heliophysics community has responded to this challenge by expressing a desire for a more open, collaborative set of analysis tools. This article summarizes the current state of these efforts and presents an overview of many of the existing Python heliophysics tools. It also outlines the challenges facing community members who are working towards the goal of an open, collaborative, Python heliophysics toolkit and presents guidelines that can ease the transition from individualistic data analysis practices to an accountable, communalistic environment., Comment: Published in JGR

Computational analysis has become ubiquitous within the heliophysics community. However, community standards for peer-review of codes and analysis have lagged behind these developments. This absence has contributed to the reproducibility crisis, where inadequate analysis descriptions and loss of scientific data have made scientific studies difficult or impossible to replicate. The heliophysics community has responded to this challenge by expressing a desire for a more open, collaborative set of analysis tools. This article summarizes the current state of these efforts and presents an overview of many of the existing Python heliophysics tools. It also outlines the challenges facing community members who are working towards the goal of an open, collaborative, Python heliophysics toolkit and presents guidelines that can ease the transition from individualistic data analysis practices to an accountable, communalistic environment., Comment: Published in JGR

Data-model validation of ground magnetic perturbation forecasts, specifically of the time rate of change of surface magnetic field, dB/dt, is a critical task for model development and for mitigation of geomagnetically induced current effects. While a current, community-accepted standard for dB/dt validation exists (Pulkkinen et al., 2013), it has several limitations that prevent more complete understanding of model capability. This work presents recommendations from the International Forum for Space Weather Capabilities Assessment Ground Magnetic Perturbation Working Team for creating a next-generation validation suite. Four recommendations are made to address the existing suite: greatly expand the number of ground observatories used, expand the number of events included in the suite from six to eight, generate metrics as a function of magnetic local time, and generate metrics as a function of activity type. For each of these, implementation details are explored. Limitations and future considerations are also discussed.

Predicting variations in the near-Earth space environment that can lead to spacecraft damage and failure is one example of "space weather" and a big space physics challenge. A project recently funded through the Los Alamos National Laboratory (LANL) Directed Research and Development (LDRD) program aims at developing a new capability to understand, model, and predict Space Hazards Induced near Earth by Large Dynamic Storms, the SHIELDS framework. The project goals are to understand the dynamics of the surface charging environment (SCE), the hot (keV) electrons representing the source and seed populations for the radiation belts, on both macro and micro-scale. Important physics questions related to particle injection and acceleration associated with magnetospheric storms and substorms, as well as plasma waves, are investigated. These challenging problems are addressed using a team of world-class experts in the fields of space science and computational plasma physics, and state-of-the-art models and computational facilities. A full two-way coupling of physics-based models across multiple scales, including a global MHD (BATS-R-US) embedding a particle-in-cell (iPIC3D) and an inner magnetosphere (RAM-SCB) codes, is achieved. New data assimilation techniques employing in situ satellite data are developed; these provide an order of magnitude improvement in the accuracy in the simulation of the SCE. SHIELDS also includes a post-processing tool designed to calculate the surface charging for specific spacecraft geometry using the Curvilinear Particle-In-Cell (CPIC) code that can be used for reanalysis of satellite failures or for satellite design., QC 20181108

The effect of inherited basin structure and rheological stratification of a basin fill on the deformation created by inversion is a topic which has not received a lot of attention. Therefore we studied the Sarajevo-Zenica basin, a late Oligocene – Miocene endemic intramontane basin, situated in the Dinarides mountains of Bosnia and Herzegovina. To establish how inherited basin properties, structural and rheological, exerted control on the inversion deformation. We carried out structural and lithological mapping to examine the basins pre-inversion evolution and analyse its effect on the inversion. Two deformation events affected the basin before inversion. It was initiated as a foredeep basin during late Oligocene - Miocene during a phase of compression, and opened further during a phase of extension associated with the opening of the Pannonian basin in the Early – Middle Miocene. The basin was inverted obliquely to its NW-SE structural trend, in the Late Miocene by a N-S oriented compression, which is generated by the convergence of the Adriatic plate into the Dinarides. Inversion created a large E-W striking thrust through the centre of the basin which connects to a detachment in the Bosnian Flysch. Folds striking E-W to NW-SE were formed. Due to the oblique angle of inversion the thrust sheet moved over oblique ramps inherited from the NW-SE trending normal fault blocks created during extension. Tear faults were formed to accommodate for the hanging wall slipping over these oblique ramps. Lateral movement along these tear faults rotated some E-W striking structures in the hanging wall to a N-S orientation. The deposition of coarse competent lithologies along the SW basin margin which transition into finer incompetent lithologies towards the NE basin margin created a rheological stratification of the basin. Where the basin fill was more competent the inherited structure exerted a stronger control in the inversion deformation, while inversion deformation in areas wi

The effect of inherited basin structure and rheological stratification of a basin fill on the deformation created by inversion is a topic which has not received a lot of attention. Therefore we studied the Sarajevo-Zenica basin, a late Oligocene – Miocene endemic intramontane basin, situated in the Dinarides mountains of Bosnia and Herzegovina. To establish how inherited basin properties, structural and rheological, exerted control on the inversion deformation. We carried out structural and lithological mapping to examine the basins pre-inversion evolution and analyse its effect on the inversion. Two deformation events affected the basin before inversion. It was initiated as a foredeep basin during late Oligocene - Miocene during a phase of compression, and opened further during a phase of extension associated with the opening of the Pannonian basin in the Early – Middle Miocene. The basin was inverted obliquely to its NW-SE structural trend, in the Late Miocene by a N-S oriented compression, which is generated by the convergence of the Adriatic plate into the Dinarides. Inversion created a large E-W striking thrust through the centre of the basin which connects to a detachment in the Bosnian Flysch. Folds striking E-W to NW-SE were formed. Due to the oblique angle of inversion the thrust sheet moved over oblique ramps inherited from the NW-SE trending normal fault blocks created during extension. Tear faults were formed to accommodate for the hanging wall slipping over these oblique ramps. Lateral movement along these tear faults rotated some E-W striking structures in the hanging wall to a N-S orientation. The deposition of coarse competent lithologies along the SW basin margin which transition into finer incompetent lithologies towards the NE basin margin created a rheological stratification of the basin. Where the basin fill was more competent the inherited structure exerted a stronger control in the inversion deformation, while inversion deformation in areas wi

The radiation belts and plasma in the Earth’s magnetosphere pose hazards to satellite systems which restrict design and orbit options with a resultant impact on mission performance and cost. For decades the standard space environment specification used for spacecraft design has been provided by the NASA AE8 and AP8 trapped radiation belt models. There are well-known limitations on their performance, however, and the need for a new trapped radiation and plasma model has been recognized by the engineering community for some time. To address this challenge a new set of models, denoted AE9/AP9/SPM, for energetic electrons, energetic protons and space plasma has been developed. The new models offer significant improvements including more detailed spatial resolution and the quantification of uncertainty due to both space weather and instrument errors. Fundamental to the model design, construction and operation are a number of new data sets and a novel statistical approach which captures first order temporal and spatial correlations allowing for the Monte-Carlo estimation of flux thresholds for user-specified percentile levels (e.g., 50th and 95th) over the course of the mission. An overview of the model architecture, data reduction methods, statistics algorithms, user application and initial validation is presented in this paper., United States. Air Force (e contracts FA8718-05-C-0036, FA8718-10-C-001, FA8721-05-C-0002 and FA8802-09-C-0001), United States. National Aeronautics and Space Administration (grant NNG05GM22G)

The effect of inherited basin structure and rheological stratification of a basin fill on the deformation created by inversion is a topic which has not received a lot of attention. Therefore we studied the Sarajevo-Zenica basin, a late Oligocene – Miocene endemic intramontane basin, situated in the Dinarides mountains of Bosnia and Herzegovina. To establish how inherited basin properties, structural and rheological, exerted control on the inversion deformation. We carried out structural and lithological mapping to examine the basins pre-inversion evolution and analyse its effect on the inversion. Two deformation events affected the basin before inversion. It was initiated as a foredeep basin during late Oligocene - Miocene during a phase of compression, and opened further during a phase of extension associated with the opening of the Pannonian basin in the Early – Middle Miocene. The basin was inverted obliquely to its NW-SE structural trend, in the Late Miocene by a N-S oriented compression, which is generated by the convergence of the Adriatic plate into the Dinarides. Inversion created a large E-W striking thrust through the centre of the basin which connects to a detachment in the Bosnian Flysch. Folds striking E-W to NW-SE were formed. Due to the oblique angle of inversion the thrust sheet moved over oblique ramps inherited from the NW-SE trending normal fault blocks created during extension. Tear faults were formed to accommodate for the hanging wall slipping over these oblique ramps. Lateral movement along these tear faults rotated some E-W striking structures in the hanging wall to a N-S orientation. The deposition of coarse competent lithologies along the SW basin margin which transition into finer incompetent lithologies towards the NE basin margin created a rheological stratification of the basin. Where the basin fill was more competent the inherited structure exerted a stronger control in the inversion deformation, while inversion deformation in areas wi

In order to allocate quotas for sustainable harvests, that account for climate warming, it is important to incorporate species vulnerabilities that will underlie likely changes in population dynamics. Hotspots, regions with rapidly changing climate, are important locations for rapid advances in mechanistic understanding of the factors driving these changes, particularly if they coincide with regions with a high incidence of range limits, such as the sub-Antarctic Island of South Georgia. This archipelago is at the Northern limit of the Southern Ocean and therefore the northern distribution limit for many Southern Ocean shallow water marine species, which are amongst the most sensitive fauna to increasing temperature. At range limits species may either be living close to their physiological limits, or they may have more resistant phenotypes. In case studies, the northern range limit population of the gastropod limpet, Nacella concinna, has greater physiological plasticity at South Georgia than those from further south, allowing them to cope better with the warmer and more variable seasonal temperatures. Bivalve species, however, alter their depth distributions at South Georgia, to avoid the warmer water masses, indicating that they may not be able to cope with the warmer temperatures. Mackerel icefish, Champsocephalus gunnari, has a unique Antarctic trait, the loss of haemoglobin. A combination of temperature driven change in food web structure, and this extreme physiological cold adaptation, may explain why rapid warming at its northern range limit of South Georgia, has prevented stocks fully recovering from over fishing in the 1980s, despite highly conservative management strategies.

Antarctic marine species have evolved in one of the coldest and most temperature-stable marine environments on Earth. They have long been classified as being stenothermal, or having a poor capacity to resist warming. Here we show that their ability to acclimate their physiology to elevated temperatures is poor compared with species from temperate latitudes, and similar to those from the tropics. Those species that have been demonstrated to acclimate take a very long time to do so, with Antarctic fish requiring up to 21–36 days to acclimate, which is 2–4 times as long as temperate species, and invertebrates requiring between 2 and 5 months to complete whole-animal acclimation. Investigations of upper thermal tolerance (CTmax) in Antarctic marine species have shown that as the rate of warming is reduced in experiments, CTmax declines markedly, ranging from 8 to 17.5°C across 13 species at a rate of warming of 1°C day−1, and from 1 to 6°C at a rate of 1°C month−1. This effect of the rate of warming on CTmax also appears to be present at all latitudes. A macrophysiological analysis of long-term CTmax across latitudes for marine benthic groups showed that both Antarctic and tropical species were less resistant to elevated temperatures in experiments and thus had lower warming allowances (measured as the difference between long-term CTmax and experienced environmental temperature), or warming resistance, than temperate species. This makes them more at risk from warming than species from intermediate latitudes. This suggests that the variability of environmental temperature may be a major factor in dictating an organism's responses to environmental change.

In order to allocate quotas for sustainable harvests, that account for climate warming, it is important to incorporate species vulnerabilities that will underlie likely changes in population dynamics. Hotspots, regions with rapidly changing climate, are important locations for rapid advances in mechanistic understanding of the factors driving these changes, particularly if they coincide with regions with a high incidence of range limits, such as the sub-Antarctic Island of South Georgia. This archipelago is at the Northern limit of the Southern Ocean and therefore the northern distribution limit for many Southern Ocean shallow water marine species, which are amongst the most sensitive fauna to increasing temperature. At range limits species may either be living close to their physiological limits, or they may have more resistant phenotypes. In case studies, the northern range limit population of the gastropod limpet, Nacella concinna, has greater physiological plasticity at South Georgia than those from further south, allowing them to cope better with the warmer and more variable seasonal temperatures. Bivalve species, however, alter their depth distributions at South Georgia, to avoid the warmer water masses, indicating that they may not be able to cope with the warmer temperatures. Mackerel icefish, Champsocephalus gunnari, has a unique Antarctic trait, the loss of haemoglobin. A combination of temperature driven change in food web structure, and this extreme physiological cold adaptation, may explain why rapid warming at its northern range limit of South Georgia, has prevented stocks fully recovering from over fishing in the 1980s, despite highly conservative management strategies.

Antarctic marine species have evolved in one of the coldest and most temperature-stable marine environments on Earth. They have long been classified as being stenothermal, or having a poor capacity to resist warming. Here we show that their ability to acclimate their physiology to elevated temperatures is poor compared with species from temperate latitudes, and similar to those from the tropics. Those species that have been demonstrated to acclimate take a very long time to do so, with Antarctic fish requiring up to 21–36 days to acclimate, which is 2–4 times as long as temperate species, and invertebrates requiring between 2 and 5 months to complete whole-animal acclimation. Investigations of upper thermal tolerance (CTmax) in Antarctic marine species have shown that as the rate of warming is reduced in experiments, CTmax declines markedly, ranging from 8 to 17.5°C across 13 species at a rate of warming of 1°C day−1, and from 1 to 6°C at a rate of 1°C month−1. This effect of the rate of warming on CTmax also appears to be present at all latitudes. A macrophysiological analysis of long-term CTmax across latitudes for marine benthic groups showed that both Antarctic and tropical species were less resistant to elevated temperatures in experiments and thus had lower warming allowances (measured as the difference between long-term CTmax and experienced environmental temperature), or warming resistance, than temperate species. This makes them more at risk from warming than species from intermediate latitudes. This suggests that the variability of environmental temperature may be a major factor in dictating an organism's responses to environmental change.

Species with broader geographical ranges are expected to be ecological generalists, while species with higher heat tolerances may be relatively competitive at more extreme and increasing temperatures. Thus, both traits are expected to relate to increased survival during transport to new regions of the globe, and once there, establishment and spread. Here, we explore these expectations using datasets of latitudinal range breadth and heat tolerance in freshwater and marine invertebrates and fishes. After accounting for the latitude and hemisphere of each species’ native range, we find that species introduced to freshwater systems have broader geographical ranges in comparison to native species. Moreover, introduced species are more heat tolerant than related native species collected from the same habitats. We further test for differences in range breadth and heat tolerance in relation to invasion success by comparing species that have established geographically restricted versus extensive introduced distributions. We find that geographical range size is positively related to invasion success in freshwater species only. However, heat tolerance is implicated as a trait correlated to widespread occurrence of introduced populations in both freshwater and marine systems. Our results emphasize the importance of formal risk assessments before moving heat tolerant species to novel locations.

Species with broader geographical ranges are expected to be ecological generalists, while species with higher heat tolerances may be relatively competitive at more extreme and increasing temperatures. Thus, both traits are expected to relate to increased survival during transport to new regions of the globe, and once there, establishment and spread. Here, we explore these expectations using datasets of latitudinal range breadth and heat tolerance in freshwater and marine invertebrates and fishes. After accounting for the latitude and hemisphere of each species’ native range, we find that species introduced to freshwater systems have broader geographical ranges in comparison to native species. Moreover, introduced species are more heat tolerant than related native species collected from the same habitats. We further test for differences in range breadth and heat tolerance in relation to invasion success by comparing species that have established geographically restricted versus extensive introduced distributions. We find that geographical range size is positively related to invasion success in freshwater species only. However, heat tolerance is implicated as a trait correlated to widespread occurrence of introduced populations in both freshwater and marine systems. Our results emphasize the importance of formal risk assessments before moving heat tolerant species to novel locations.

Thoracic ventral dural defect, and resultant idiopathic spinal cord herniation, is a rare but increasingly recognized cause of a chronic progressive thoracic myelopathy, particularly in middle-aged women. A neurosurgically confirmed case is presented, together with a review of the pathogenesis, clinical presentation, imaging features, treatment options and progress of this entity post-treatment. © 2006 Royal Australian and New Zealand College of Radiologists.

Thoracic ventral dural defect, and resultant idiopathic spinal cord herniation, is a rare but increasingly recognized cause of a chronic progressive thoracic myelopathy, particularly in middle-aged women. A neurosurgically confirmed case is presented, together with a review of the pathogenesis, clinical presentation, imaging features, treatment options and progress of this entity post-treatment. © 2006 Royal Australian and New Zealand College of Radiologists.

Intracerebral abscesses are associated with significant morbidity and mortality. We report the case of a healthy 16 year-old male who presented with seizure and was found to have multifocal Streptococcus intermedius brain abscesses. Further studies determined the patient had necrotizing hilar lymphadenopathy and pneumonia by chest computed tomography (CT) and positive serologic testing for infection by Histoplasma capsulatum. The patient was treated with meropenem and recovered completely. The histoplasma infection resolved without anti-fungal therapy.

This study examines the changes in self-perception during resolution of an acutely painful neck injury sustained in a motor vehicle accident. We tested predictions from self-discrepancy theory and a model of self-pain enmeshment. Measures of discrepancy between the current (actual) self and both the ideal and feared-for self were predicted to remain stable over a 21-day recovery period whereas a measure of enmeshment was predicted to decrease as pain resolved. We also examined the relationship between daily ratings of achievement in several domains and participants perceived ideal performance. Sixty patients with possible acute neck injury recruited within 1 month after a motor vehicle accident gave consent and data were obtained from 42 participants. Standard questionnaire measures of pain, disability, fear of movement, pain catastrophizing and self-discrepancies, self-pain enmeshment and data from diaries (measures of pain, mood, self-discrepancies, pain catastrophizing and fear of movement) were obtained. In general the relationships between the measures of self-discrepancy and enmeshment and mood were in accord with both theoretical predictions and previous observations. Resolution of pain was associated with a reduction in enmeshment but not to change in self-discrepancy. Multilevel analyses of the diary data showed that concordance between actual and ideal performance increased over the 21 days of data collection. These data provide preliminary support for aspects of self-discrepancy theory and the self-pain enmeshment model. (PsycINFO Database Record (c) 2011 APA, all rights reserved) (journal abstract)

This study examines the changes in self-perception during resolution of an acutely painful neck injury sustained in a motor vehicle accident. We tested predictions from self-discrepancy theory and a model of self-pain enmeshment. Measures of discrepancy between the current (actual) self and both the ideal and feared-for self were predicted to remain stable over a 21-day recovery period whereas a measure of enmeshment was predicted to decrease as pain resolved. We also examined the relationship between daily ratings of achievement in several domains and participants perceived ideal performance. Sixty patients with possible acute neck injury recruited within 1 month after a motor vehicle accident gave consent and data were obtained from 42 participants. Standard questionnaire measures of pain, disability, fear of movement, pain catastrophizing and self-discrepancies, self-pain enmeshment and data from diaries (measures of pain, mood, self-discrepancies, pain catastrophizing and fear of movement) were obtained. In general the relationships between the measures of self-discrepancy and enmeshment and mood were in accord with both theoretical predictions and previous observations. Resolution of pain was associated with a reduction in enmeshment but not to change in self-discrepancy. Multilevel analyses of the diary data showed that concordance between actual and ideal performance increased over the 21 days of data collection. These data provide preliminary support for aspects of self-discrepancy theory and the self-pain enmeshment model. (PsycINFO Database Record (c) 2011 APA, all rights reserved) (journal abstract)

BACKGROUND: The present study was conducted to investigate the anatomy of the motor nerve to the gracilis muscle (MNG) to provide the anatomical basis for harvesting a one-stage gracilis transfer with a long nerve for re-animation of the paralysed face. METHODS: An anatomical study was performed on 24 lower-limb specimens (from the pelvis down to the knee) from 12 embalmed cadavers. The MNG was dissected from the surface of the muscle to the obturator foramen. Two anatomical regions were defined in the course of the nerve. The first region includes the part of the nerve that can easily be reached through a standard incision in the medial aspect of the thigh, that is, from the surface of the muscle to the posterior border of the adductor brevis muscle and the second region from there to the obturator foramen. Measurements of both anatomical regions and the maximum length of the nerve were taken with a calliper. The anatomical relations of the nerve were also noted and photo-documented. RESULTS: The median maximum length of the MNG from the surface of gracilis to the posterior border of adductor brevis ('first anatomical region') was 7.7 cm (Range 6.3-10.5 cm); from there to the obturator foramen ('second anatomical region') the length was 3.7 cm (Range 2-6 cm), giving a median length of dissection of the nerve as 11.5 cm (Range 9.9-13.6 cm). Intraneural dissection of the MNG has to be performed proximally in the course of the nerve (the part corresponding to the second anatomical region), just where it runs inside the fascia over the obturator externus muscle. CONCLUSIONS: Over 10-cm length of the MNG can be obtained when dissected along the course of the nerve up to the obturator foramen. To achieve the maximum length, intraneural dissection must normally be performed after the nerve passes the posterior border of the adductor brevis. An endoscopic approach or extended proximal incision is recommended to easily reach the proximal part of the nerve as far as the obtu

To fully understand how species distributions will respond to changing environments it is essential to understand the mechanisms underlying variation in animal performance and the relative importance of different ecological and environmental factors. A performance measure that has previously been used as an indicator of thermal capacity of the Antarctic limpet (Nacella concinna) to cope with regional warming is the ability to right if removed from the substratum and turned upside down. As part of an on-going study into limpet genetics and phenotypic plasticity, we tested the temperature limits for 50% righting of limpets from 6 and 30 m depth. The 50% threshold for limpets collected from 6 m (4.7 degrees C) was higher than for those collected from 30 m (0.7 degrees C). This compares with a previously published limit of 2.2 degrees C for limpets collected from 12-15 m at the same location. These thermal limits positively correlated with a depth gradient in shell height to length ratio; thickness and strength. Flatter limpets, had a reduced thermal limit for righting than taller limpets which we hypothesise is related to increased energy requirements of flat limpets, which have to turn through a greater angle to right than tall limpets. Of the factors that cause morphological plasticity of gastropod shells, iceberg disturbance is the most likely cause of the sub-tidal gradient in N. concinna shell shape, and therefore the thermal limit for righting of limpets from 6 to 30 m depth, rather than environmental temperature. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.

To fully understand how species distributions will respond to changing environments it is essential to understand the mechanisms underlying variation in animal performance and the relative importance of different ecological and environmental factors. A performance measure that has previously been used as an indicator of thermal capacity of the Antarctic limpet (Nacella concinna) to cope with regional warming is the ability to right if removed from the substratum and turned upside down. As part of an on-going study into limpet genetics and phenotypic plasticity, we tested the temperature limits for 50% righting of limpets from 6 and 30 m depth. The 50% threshold for limpets collected from 6 m (4.7 degrees C) was higher than for those collected from 30 m (0.7 degrees C). This compares with a previously published limit of 2.2 degrees C for limpets collected from 12-15 m at the same location. These thermal limits positively correlated with a depth gradient in shell height to length ratio; thickness and strength. Flatter limpets, had a reduced thermal limit for righting than taller limpets which we hypothesise is related to increased energy requirements of flat limpets, which have to turn through a greater angle to right than tall limpets. Of the factors that cause morphological plasticity of gastropod shells, iceberg disturbance is the most likely cause of the sub-tidal gradient in N. concinna shell shape, and therefore the thermal limit for righting of limpets from 6 to 30 m depth, rather than environmental temperature. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.

The images taken by the Heliospheric Imagers (HIs), part of the SECCHI imaging package onboard the pair of STEREO spacecraft, provide information on the radial and latitudinal evolution of the plasma compressed inside corotating interaction regions (CIRs). A plasma density wave imaged by the HI instrument onboard STEREO-B was found to propagate towards STEREO-A, enabling a comparison between simultaneous remote-sensing and in situ observations of its structure to be performed. In situ measurements made by STEREO-A show that the plasma density wave is associated with the passage of a CIR. The magnetic field compressed after the CIR stream interface (SI) is found to have a planar distribution. Minimum variance analysis of the magnetic field vectors shows that the SI is inclined at 54° to the orbital plane of the STEREO-A spacecraft. This inclination of the CIR SI is comparable to the inclination of the associated plasma density wave observed by HI. A small-scale magnetic cloud with a flux rope topology and radial extent of 0.08 AU is also embedded prior to the SI. The pitch-angle distribution of suprathermal electrons measured by the STEREO-A SWEA instrument shows that an open magnetic field topology in the cloud replaced the heliospheric current sheet locally. These observations confirm that HI observes CIRs in difference images when a small-scale transient is caught up in the compression region.

Superposed epoch analyses have shown that, on average, the interplanetary magnetic field (IMF) turns northward close to substorm onset. This has been commonly accepted as evidence for the substorm onset being triggered by a rapid northward turning of the IMF. Here we show that the tendency arises in any superposed epoch analysis of the IMF in which event onset is biased to occur for southward IMF, irrespective of a coincident rapid northward turning of the IMF. The overall IMF variation found in the largest superposed epoch analysis of this kind is also well reproduced using a Minimal Substorm Model in which substorm onsets are determined without the requirement of a northward IMF turning trigger. We discuss the explanation underlying these results and conclude that there is no conclusive evidence in favour of the hypothesis that substorm onsets are triggered by a rapid northward turning of the IMF. Citation: Freeman, M. P., and S. K. Morley (2009), No evidence for externally triggered substorms based on superposed epoch analysis of IMF B-z, Geophys. Res. Lett., 36, L21101, doi: 10.1029/2009GL040621.

The images taken by the Heliospheric Imagers (HIs), part of the SECCHI imaging package onboard the pair of STEREO spacecraft, provide information on the radial and latitudinal evolution of the plasma compressed inside corotating interaction regions (CIRs). A plasma density wave imaged by the HI instrument onboard STEREO-B was found to propagate towards STEREO-A, enabling a comparison between simultaneous remote-sensing and in situ observations of its structure to be performed. In situ measurements made by STEREO-A show that the plasma density wave is associated with the passage of a CIR. The magnetic field compressed after the CIR stream interface (SI) is found to have a planar distribution. Minimum variance analysis of the magnetic field vectors shows that the SI is inclined at 54° to the orbital plane of the STEREO-A spacecraft. This inclination of the CIR SI is comparable to the inclination of the associated plasma density wave observed by HI. A small-scale magnetic cloud with a flux rope topology and radial extent of 0.08 AU is also embedded prior to the SI. The pitch-angle distribution of suprathermal electrons measured by the STEREO-A SWEA instrument shows that an open magnetic field topology in the cloud replaced the heliospheric current sheet locally. These observations confirm that HI observes CIRs in difference images when a small-scale transient is caught up in the compression region.

Superposed epoch analyses have shown that, on average, the interplanetary magnetic field (IMF) turns northward close to substorm onset. This has been commonly accepted as evidence for the substorm onset being triggered by a rapid northward turning of the IMF. Here we show that the tendency arises in any superposed epoch analysis of the IMF in which event onset is biased to occur for southward IMF, irrespective of a coincident rapid northward turning of the IMF. The overall IMF variation found in the largest superposed epoch analysis of this kind is also well reproduced using a Minimal Substorm Model in which substorm onsets are determined without the requirement of a northward IMF turning trigger. We discuss the explanation underlying these results and conclude that there is no conclusive evidence in favour of the hypothesis that substorm onsets are triggered by a rapid northward turning of the IMF. Citation: Freeman, M. P., and S. K. Morley (2009), No evidence for externally triggered substorms based on superposed epoch analysis of IMF B-z, Geophys. Res. Lett., 36, L21101, doi: 10.1029/2009GL040621.