Search

Polymer mixing is often challenging under offshore conditions due to space constraints. A theoretical approach is required to better understand the drivers for polymer hydration and design optimal field mixing systems. We share a novel theoretical approach to gain insights into the energy required for optimum mixing of novel liquid polymers. We present a new parameter, "Specific Mixing Energy" that is measured under both lab and field mixing conditions and can be used to scale-up laboratory mixing. We developed a simplified laboratory mixing process for novel liquid polymer that provided acceptable viscosity yield, filtration ratio (FR), and non-plugging behavior during injectivity tests in a surrogate core. A FR less than 1.5 using a 1.2 μm filter at 1 bar was considered acceptable for inverted polymer quality. We developed estimates for specific mixing energy required for lab polymer inversion to achieve these stringent FR standards and comparable viscosity yield. We then conducted yard trials with both single-stage and dual-stage mixing of the novel liquid polymer and developed correlations for specific mixing energy under dynamic conditions. Based upon the results of lab and yard trials, we tested the approach in a field injectivity test. The FR and viscosity were also correlated to a specific mixing energy to establish the desired operating window range from laboratory to field-scale applications. Such information can be used to enhance EOR applications using liquid polymers in offshore environments.

Field deployment of Chemical EOR floods requires monitoring of wellhead injection fluids to ensure field performance is commensurate with laboratory design. Real-time surveillance allows for optimizing chemical use, detecting potential issues, and ensures correct chemical handling. In an offshore setting traditional surveillance methods can present unique challenges due to space constraints, field conditions, and location. We present a novel approach to field surveillance using a portable measurement unit (PMU) that can dynamically characterize polymer rheology, filterability and long-term core-injectivity.We developed a PMU and placed it inside a suitcase sized box (42x26x20″) with appropriate devices to measure polymer rheology, filterability and long-term core injectivity. Polymer rheology was measured using a series of capillary tubes with pressure measurements. Filterability was measured through a 1.2 um filter at 15 psi with coarse filtration to remove large oil droplets and suspended solids. This was compared against filterability without filtration to observe water quality impact. Finally, long-term injectivity was measured using an epoxy-coated Bentheimer core with a pressure tap to quantify whether there was any face and/or core-plugging. By constructing this apparatus, wellhead injection fluids under anaerobic conditions can be monitored and analyzed to improve fluid quality assurance and contribute to a project's success even in challenging and remote locations.The use of the PMU is critical for dynamic fluid surveillance. The injection solutions consistently met or exceeded target viscosity of 20 cP. Furthermore, the coarse-filtered solutions also met a filtration ratio (FR) requirements of less than 1.5 at 15 psi through 1.2 micron filters. The unfiltered solutions achieved a FR of 1.75, which was considered acceptable. Finally, no plugging was observed with coarse-filtered solutions after 25 PV across the whole core and > 75 PV across the core face. Further testing was completed with wellhead injectate samples at variable operating conditions to establish a baseline for chemical flooding operations and provided insight for future facilities design.The information these experiments produced helped identify and diagnose facility and operational issues that would have caused negative consequences with the chemical injection had the configuration been used without the PMU surveillance. By testing the wellhead fluid, we determined that there was improper dosing of the chemical. This was determined by comparing the field fluid properties to expected results from the lab. The data also influenced facilities design and in turn improved the chemical and project efficiency. By testing the injectate at different operating conditions we could determine the operating envelope for the current injection facilities and base future work on the results. All of this was done in real time on an offshore platform, as opposed to sending samples onshore to test which yields unrepresentative results from the time delay and fluid quality changes during transport.

Guidelines strongly recommend patients with ST-elevation myocardial infarction (STEMI) receive timely mechanical reperfusion, defined as door-to-balloon time (DTBT) ≤90 minutes. The impact of timely reperfusion on clinical outcomes in patients aged 75-84 and ≥85 years is uncertain. We analysed 2,972 consecutive STEMI patients who underwent primary percutaneous coronary intervention from the Melbourne Interventional Group Registry (2005-2014). Patients aged

Background: Guidelines for patients with ST-elevation myocardial infarction include a door-to-balloon time (DTBT) of ≤90 min for primary percutaneous coronary intervention. Aim: The aim of this study was to assess temporal trends (2006–2010) in DTBT and determine if a reduction in DTBT was associated with improved clinical outcomes. Methods: We compared annual median DTBT in 1926 STEMI patients undergoing primary percutaneous coronary intervention from the Melbourne Interventional Group registry. ST-elevation myocardial infarction presenting >12 h and rescue percutaneous coronary intervention was excluded. Major adverse cardiac events were analysed according to DTBT (dichotomised as ≤90 min vs >90 min). A multivariable analysis for predictors of mortality (including DTBT) was performed. Results: Baseline demographics, clinical and procedural characteristics were similar in the STEMI cohort across the 5 years, apart from an increase in out-of-hospital cardiac arrest (3.6% in 2006 vs 9.4% in 2010, P < 0.0001) and cardiogenic shock (7.7–9.6%, P = 0.07). The median DTBT (interquartile range) was reduced from 95 (74–130) min in 2006 to 75 (51–100) min in 2010 (P < 0.01). In this period, the proportion of patients achieving a DTBT of ≤90 min increased from 45% to 67% (P < 0.01). Lower mortality and major adverse cardiac event rates were observed with DTBT ≤90 min (allP < 0.01). Multivariable analysis showed that a DTBT of ≤90 min was associated with improved clinical outcomes at 12 months (odds ratio 0.48; 95% confidence interval 0.33–0.73, P < 0.01). Conclusion: There has been a decline in median DTBT in the Melbourne Interventional Group registry over 5 years. DTBT of ≤90 min is associated with improved clinical outcomes at 12 months.

BACKGROUND: Stroke neurologists, vascular surgeons, interventional neuroradiologists and interventional cardiologists have embraced carotid angioplasty and stenting (CAS) because of potential advantages over carotid endarterectomy (CEA). At Austin Health, a multidisciplinary neuro-interventional group was formed to standardise indications and facilitate training. The aims of this study were to describe our organisational model and to determine whether 30-day complications and early outcomes were similar to those of major trials. METHODS: A clinical protocol was developed to ensure optimal management. CAS was performed on patients with high medical risk for CEA, with technically difficult anatomy for CEA, or who were randomised to CAS in a trial. RESULTS: From October 2003 to May 2008, 47 patients (34 male, mean age 71.5) underwent CAS of 50 carotid arteries. Forty-three cases had ipsilateral carotid territory symptoms within the previous 12 months. The main indications for CAS were high risk for CEA (n= 17) and randomised to CAS (n= 21). Interventionists were proctored in 27 cases. The procedural success rate was 94% with two cases abandoned because of anatomical problems and one because of on-table angina. Hypotension requiring vasopressor therapy occurred in 12 cases (24%). The duration of follow up was one to 44 months (mean 6.8 months). The 30-day rate of peri-procedural stroke or death was 6% and the one-year rate of peri-procedural stroke or death or subsequent ipsilateral stroke was 10.6%. Restenosis occurred in 13% (all asymptomatic). CONCLUSION: A multidisciplinary approach is a useful strategy for initiating and sustaining a CAS programme.

BACKGROUND The endovascular treatment of carotid atherosclerosis with carotid artery stenting (CAS) remains controversial. Carotid endarterectomy remains the benchmark in terms of procedural mortality and morbidity. At present, there are no consensus Australasian guidelines for the safe performance of CAS. METHODS We applied a modified Delphi consensus method of iterative consultation between the College representatives on the Carotid Stenting Guidelines Committee (CSGC). RESULTS Selection of patients suitable for CAS needs careful consideration of clinical and patho-anatomical criteria and cannot be directly extrapolated from clinical indicators for carotid endarterectomy (CEA). Randomized controlled trials (including pooled analyses of results) comparing CAS with CEA for treatment of symptomatic stenosis have demonstrated that CAS is more hazardous than CEA. On current evidence, the CGSC therefore recommends that CAS should not be performed in the majority of patients requiring carotid revascularisation. The evidence for CAS in patients with symptomatic severe carotid stenosis who are considered medically high risk is weak, and there is currently no evidence to support CAS as a treatment for asymptomatic carotid stenosis. The use of distal protection devices during CAS remains controversial with increased risk of clinically silent stroke. The knowledge requirements for the safe performance of CAS include an understanding of the evidence base from randomized controlled trials, carotid and aortic arch anatomy and pathology, clinical stroke syndromes, the differing treatment options for stroke and carotid atherosclerosis, and recognition and management of periprocedural complications. It is critical that all patients being considered for a carotid intervention have adequate pre-procedural neuro-imaging and an independent, standardized neurological assessment before and after the procedure. Maintenance of proficiency in CAS requires active involvement in surgical/endovascular audit and continuing medical education programs. These standards should apply in the public and private health care settings. CONCLUSION These guidelines represent the consensus of an inter-collegiate committee in order to direct appropriate patient selection and the range of cognitive and technical requirements to perform CAS. Advances in endovascular technologies and the results of randomized controlled trials will guide future revisions of these guidelines.

Dambos are shallow, seasonally inundated wetlands and are a widespread landform in Central and Southern Africa. Owing to their importance in local agriculture and as a water resource, the hydrology of dambos is of considerable interest: varied, and sometimes contradictory, hydrological characteristics have been described in the literature. The issues in contention focus on the role of the dambo in (i) the catchment evapotranspiration (ET) budget, (ii) flood flow retardation and attenuation, and (iii) sustaining dry season flow to the river down-stream. In addition, both rainfall and groundwater have been identified as the dominant source of water to the dambo and various hydrogeological models have been proposed to describe the hydrological functions of the landform. In this paper, hydrological and geochemical data collected over a full hydrological year are used to investigate and describe the hydrological functions of a dambo in north-western Zambia. The Penman estimate of wetland ET was less than the ET from the miombo-wooded interfluve and the wetland has been shown to have little effect on flood flow retardation or attenuation. Discharge of water stored within the wetland contributed little to the dry season flow from the dambo, which was sustained primarily by groundwater discharge. Flow in a perched aquifer within the catchment soils contributed a large portion of baseflow during the rains and early dry season. This source ceased by the mid dry season, implying that the sustained middle to late dry season streamflow from the wetland is through discharge of a deeper aquifer within the underlying regolith or bedrock. This hypothesis is tested through an analysis of groundwater and wetland geochemistry. Various physical parameters, PHREEQC model results and end member mixing analysis (EMMA) suggest strongly that the deep Upper Roan dolomite aquifer is the source of sustained discharge from the wetland. Keywords: dambo, hydrology, hydrogeology, stormflow, evapotranspiration, baseflow, sponge effect, Zambia

The search for useful model systems to study sensory processing in vertebrate nervous systems has resulted in many neuroethological studies investigating the roles played by a single sensory modality in a given behavior. However, animals behaving in a complex, three-dimensional environment receive a large amount of information from external and internal receptor arrays. Clearly, the integration of sensory afference arising from different modalities into a coherent ‘gestalt’ of the world is essential to the behaviors of most animals. Over the past several years researchers in my laboratory have examined the roles played by the visual and lateral line sensory systems in organizing the feeding behavior of two species of predatory teleost fishes, the largemouth bass, Micropterus salmoides and the muskellunge, Esox masquinongy. The free-field feeding behaviors of these fishes was studied quantitatively in intact animals and compared to animals in which the lateral line and visual systems had been selectively suppressed. The data show that both bass and muskie employ similar approach and strike behaviors. Vision is crucial to the initial detection of, and orientation to, prey. Lateral line and vision together determine the optimum distance and angular deviation for the initiation of a rapid strike toward the prey. Blinded animals are able to strike accurately at prey at very close ranges and small angular deviations, indicating that this modality presents sufficient information to direct the behavior during the final phases of the strike. The results demonstrate that there is a hierarchy of senses involved in feeding behavior, with different modalities playing critical roles in succeeding phases.

The organization of the vertebrate cerebellum has been thoroughly studied over the past century, but the function of this structure remains poorly understood. In elasmobranch fishes, the cerebellum displays tremendous variation in size and development although the basic and conservative nature of cerebellar circuitry as seen in other vertebrate taxa is largely retained. Large and morphologically complex cerebelli have evolved independently in both sharks and batoids, and the relative development of this structure in both taxa parallels those of birds and mammals. There are relatively few studies of the physiological role of the cerebellum in generating or shaping behaviors, however, and a convincing explanation of cerebellar hypertrophy in elasmobranchs is lacking. The purpose of this article is to review the current understanding of the structure of the cerebellum in elasmobranch fishes, the physiological responses of cerebellar neurons and the possible role of the cerebellum in behavior. I will also provide a number of hypotheses for future research directions, based upon models that have been suggested by different investigators. These hypotheses include models of cerebellar function as a sensory coincidence detector, a dynamic state estimator and/or a direct modulator of motor programs. Hypotheses concerning the possible organization of cerebellar microcomplexes, the evolution of afferent and efferent cerebellar connections paralleling those observed in mammals and the role of the cerebellum in learning are also suggested.

The search for useful model systems for the study of sensory processing in vertebrate nervous systems has resulted in many neuroethological studies investigating the roles played by a single sensory modality in a given behaviour. However, behaviours relying solely upon information from one sensory modality are relatively rare. Animals behaving in a complex, three–dimensional environment receive a large amount of information from external and internal receptor arrays. Clearly, the integration of sensory afference arising from different modalities into a coherent ‘gestalt’ of the world is essential to the behaviours of most animals. In the last several years our laboratory team has examined the roles played by the visual and lateral line sensory systems in organizing the feeding behaviour of two species of predatory teleost fishes, the largemouth bass,Micropterus salmoides, and the muskellunge,Esox masquinongy. The free–field feeding behaviours of these fishes were studied quantitatively in intact animals and compared to animals in which the lateral line and visual systems had been selectively suppressed. All groups of animals continued to feed successfully, but significant differences were observed between each experimental group, providing strong clues as to the relative role played by each sensory system in the organization of the behaviour. Furthermore, significant differences exist between the two species. The differences in behaviour resulting when an animal is deprived of a given sensory modality reflect the nature of central integrative sensory processes, and these behavioural studies provide a foundation for further neuroanatomical and physiological studies of sensory integration in the vertebrate central nervous system.

Retrograde transport of horseradish peroxidase was used to determine the descending projections to the spinal cord in an otophysan fish, the channel catfish, Ictalurus punctatus. The majority of cells projecting to the spinal cord are located in the reticular formation, which is organized into rhombomeric segments. Vestibulospinal neurons are located in the descending, magnocellular, and tangential octaval nuclei, as well as in the medial octavolateralis nucleus of the lateral line system. Cells in the facial lobe project to the spinal cord. Additionally, axons of cells of the trigeminal system and the nucleus of the lateral lemniscus project caudally into the spinal cord. In the midbrain, descending spinal projections arise from cells of the medial longitudinal fasciculus and the red nucleus. More rostrally, cells of the ventrolateral thalamus, dorsal periventricular hypothalamus, central pretectal and magnocellular preoptic nuclei also project to the cord. The results of this study indicate that there are a number of homologies in the descending systems of bony fishes and other vertebrate taxa, including tetrapods. We also provide further evidence that a red nucleus is present in the brains of bony fishes and is therefore a primitive vertebrate character antedating the evolution of tetrapods. Anat. Rec. 252:235–253, 1998. © 1998 Wiley-Liss, Inc.

Since the 1940s, perceived companion animal overpopulation in the United States has been an important issue to the animal welfare community (Moulton, Wright, & Rinky, 1991). This surplus of animals has resulted in millions of dogs and cats being euthanized annually in animal shelters across the country. The nature and scope of this problem have been notoriously difficult to characterize. The number of animal shelters in the United Stares, the demographics of the population of animals passing through them, and the characteristics of per owners relinquishing animals are poorly understood. What portion of these animals are adopted or euthanized, why they are relinquished, and their source of acquisition are all questions for which there have been little data. Consequently, we are no closer to answering the fundamental question of how and why many animals are destroyed each year in shelters (Arkow, 1994).

Nucleus praeeminentialis (nPr) is an isthmic nucleus that has been described in the brains of electrosensory teleost fishes and a single non-electrosensory species. The nucleus receives axon collaterals of ascending medullary sensory lemniscal neurons. Axons of nPr neurons project in turn back down onto those same populations of medullary projection neurons via a descending parallel fiber system (the molecular layer or cerebellar crest). Thus nPr forms a link in a sensory feedback loop that modulates the activity of neurons that relay information from medulla to midbrain. The purpose of this study is to investigate the nature of the afferent and efferent connections of the nPr with the specific aim of investigating other sources of input into this modulatory circuit. Transport of neuronal tracers (horseradish peroxidase, DiI and dextran amines) revealed that nPr has extensive interconnections with nuclei in the basal metencephalon, cerebellum, octavolateralis column and basal medulla. A previously described source of afference, the torus semicircularis in the mesencephalon, was not indicated by our studies. Our studies suggest that in addition to regulating the sensitivity and resolution of electrosensory and mechanosensory lateral line systems, the nPr may play a role in the resolution of signal ambiguities posed by auditory or vestibular stimulation of the saccular endorgan of the inner ear.

Elasmobranch fishes localize weak electric sources at field intensities of5 eta V cm-1, but the response dynamics of electrosensory primary afferent neurons to near threshold stimuli in situ are not well characterized. Electrosensory primary afferents in the round stingray, Urolophus halleri, have a relatively high discharge rate, a regular discharge pattern and entrain to 1-Hz sinusoidal peak electric field gradients ofor = 20 eta V cm-1. Peak neural discharge for units increases as a non-linear function of stimulus intensity, and unit sensitivity (gain) decreases as stimulus intensity increases. Average peak rate-intensity encoding is commonly lost when peak spike rate approximately doubles that of resting, and for many units occurs at intensities1 microV cm-1. Best neural sensitivity for nearly all units is at 1-2 Hz with a low-frequency slope of 8 dB/decade and a high-frequency slope of -23 dB/decade. The response characteristics of stingray electrosensory primary afferents indicate sensory adaptations for detection of extremely weak phasic fields near 1-2 Hz. We argue that these properties reflect evolutionary adaptations in elasmobranch fishes to enhance detection of prey, communication and social interactions, and possibly electric-mediated geomagnetic orientation.

The medial octavolateralis nucleus (MON) is the principal first-order medullary lateral line sensory nucleus found in the majority of anamniotic vertebrates. Although its presence has been confirmed in numerous taxa, the cytoarchitecture of this region has not been extensively studied in any species. The purpose of this study was to examine in detail the cytoarchitecture of the MON in the goldfish using Golgi staining and HRP histochemical techniques. The results of this study demonstrated the presence of a number of cell types with distinct cellular morphologies, several of which strongly resemble those described in octavolateralis nuclei dedicated to audition and electroreception. The most prominent of these MON neurons included crest cells of two varieties, either possessing or lacking basilar dendrites. Additionally, we described stellate and cristal interneurons and granule-like cells in the molecular layer, and lateral interneurons and granule-like neurons in deeper MON layers. These morphological similarities together with similarities in functional organization, and the probable close phyletic relationships of this "family" of hair cell sensory systems, argue for parallels in mechanisms of sensory processing and analysis in strongly divergent sensory modalities.

The utility of intramolecular anodic olefin coupling reactions involving electron-rich aromatic rings for constructing fused, bicyclic ring skeletons has been examined. Reactions involving alkoxy-substituted phenyl rings were found to benefit strongly from a 3-methoxy substituent on the phenyl ring. Although overoxidation of the bicyclic product was observed in these reactions, this problem could be minimized with the use of controlled potential electrolysis conditions when a monomethoxy phenyl ring was used and avoided entirely with the use of a vinyl sulfide moiety as the initiator when a more electron-rich phenyl ring was used. Reactions involving 4-alkoxy-substituted phenyl rings as substrates did not lead to good yields of fused products. Furan rings were found to be excellent coupling partners for the reactions and afforded products having fused, bicyclic furan ring skeletons. Cyclizations involving furans were shown to be compatible with the formation of both six- and seven-membered rings, the generation of a quaternary carbon, and the use of a variety of electron-rich olefins as the other coupling partner. It appears that the furan can serve as either the initiating group or the terminating group for the cyclizations. Finally, the reactions were shown to be compatible with the use of a pyrrole ring as one of the participants.

The pK values of the conjugate acids of N-phenylhydroxylamines change drastically when the pK values are determined in dimethyl sulfoxide (DMSO) rather than methanol. The Hammett ρ values change from −5·69 to −1·20 on going from methanol to DMSO for protonated N-phenylhydroxylamines, in contrast to a shift of −4·70 to −4·83 for protonated N-methylanilines in the same two solvents. This large change in susceptibility indicates that the species from which the proton departs is not the same for protonated N-phenylhydroxylamines in the two solvents. Experimental and computational evidence supports ionization of the H+ from the O atom for the protonated N-phenylhydroxylamines in DMSO.

Skates possess bilateral electric organs that produce intermittent, weak discharges of relatively long duration compared to the discharges of other weakly electric fish. They, like all elasmobranchs, also have an electrosensory system capable of detecting weak, low-frequency electric fields. Several studies have suggested that the discharge is used in some type of social communication. This study measured the strength and nature of the response of the skate electrosensory system to electric organ discharge. Electric organ discharge (EOD) was elicited via electrical stimulation of the medullary command nucleus in two species of skates. The temporal structure and power spectra of the EODs demonstrated that they should be effective stimuli for the skate electrosensory system. The responses of electrosensory afferent fibers in the anterior lateral line nerve (ALLN) to EODs were variable depending upon the location and orientation of the receptor. The responses of most ALLN fibers were very weak compared to the strong reafference produced by the skate's ventilatory activity. Unlike the common-mode ventilatory reafference, EOD reafference was variable in terms of excitation or inhibition, depending upon receptor orientation. Despite the low signal-to-noise ratio observed in ALLN responses to EODs, it is likely that EODs serve as a communicative signal over moderate distances.

Intramolecular anodic olefin coupling reactions involving electron-rich aryl rings were examined and shown to afford fused bicyclic products. When alkoxysubstituted phenyl rings were used, the reactions benefited from the use of either controlled potential electrolysis conditions or a vinyl sulfide initiating group. Coupling reactions involving heteroatomic aryl rings also led to good yields of cyclized product.

Electroreception evolved in the catfishes probably as a specialization of the mechanosensory lateral line system. Fibers of the anterior lateral line nerve in catfishes innervate electrosensory ampullary organs and mechanosensory neuromasts of the head lateral line system. The purpose of this study is to determine the projection patterns of the major principal branches of the ALLN and to investigate the topography within the various nuclei of the terminal fields of these different branches. Fibers of the superficial ophthalmic, buccal and hyomandibular branches of the anterior lateral line nerve terminate in a somatotopic fashion within medullary and cerebellar nuclei. These fibers project to, and terminate within, several discrete nuclei in the medulla and cerebellum, notably the electrosensory lateral line lobe, the medial and caudal octavolateralis nuclei, and portions of a nuclear complex in the cerebellum called the eminentia granularis. Furthermore, the dorsoventral somatotopy in the medullary electrosensory nucleus is a reversed or 'mirror' image of that in the mechanosensory nucleus. This reversed map is similar to that observed in other electrosensory systems and suggests that there may be a common mechanism for the copying and preservation of spatial information as new systems are evolved from primitive sensory pathways.

Intramolecular anodic olefin coupling reactions involving electron-rich aryl rings were examined and shown to afford fused bicyclic products. When alkoxysubstituted phenyl rings were used, the reactions benefited from the use of either controlled potential electrolysis conditions or a vinyl sulfide initiating group. Coupling reactions involving heteroatomic aryl rings also led to good yields of cyclized product.

Stroke neurologists, vascular surgeons, interventional neuroradiologists and interventional cardiologists have embraced carotid angioplasty and stenting (CAS) because of potential advantages over carotid endarterectomy (CEA). At Austin Health, a multidisciplinary neuro-interventional group was formed to standardise indications and facilitate training. The aims of this study were to describe our organisational model and to determine whether 30-day complications and early outcomes were similar to those of major trials.A clinical protocol was developed to ensure optimal management. CAS was performed on patients with high medical risk for CEA, with technically difficult anatomy for CEA, or who were randomised to CAS in a trial.From October 2003 to May 2008, 47 patients (34 male, mean age 71.5) underwent CAS of 50 carotid arteries. Forty-three cases had ipsilateral carotid territory symptoms within the previous 12 months. The main indications for CAS were high risk for CEA (n= 17) and randomised to CAS (n= 21). Interventionists were proctored in 27 cases. The procedural success rate was 94% with two cases abandoned because of anatomical problems and one because of on-table angina. Hypotension requiring vasopressor therapy occurred in 12 cases (24%). The duration of follow up was one to 44 months (mean 6.8 months). The 30-day rate of peri-procedural stroke or death was 6% and the one-year rate of peri-procedural stroke or death or subsequent ipsilateral stroke was 10.6%. Restenosis occurred in 13% (all asymptomatic).A multidisciplinary approach is a useful strategy for initiating and sustaining a CAS programme.

The endovascular treatment of carotid atherosclerosis with carotid artery stenting (CAS) remains controversial. Carotid endarterectomy (CEA) remains the benchmark in terms of procedural mortality and morbidity. Consensus Australasian guidelines for the safe performance of CAS were developed using the modified Delphi consensus method of iterative consultation. Selection of patients suitable for CAS needs careful consideration of clinical and patho-anatomical criteria. Randomised controlled trials and pooled analyses have demonstrated that CAS is more hazardous than CEA. The CGSC therefore recommends that CAS should not be performed in the majority of patients requiring carotid revascularisation. There is currently no evidence to support CAS as a treatment for asymptomatic carotid stenosis. The use of distal protection devices during CAS remains controversial with increased risk of clinically silent stroke. The knowledge requirements for the safe performance of CAS include an understanding of the evidence base from randomised controlled trials, carotid and aortic arch anatomy and pathology, and recognition and management of periprocedural complications. It is critical that all patients being considered for a carotid intervention have adequate pre-procedural neuroimaging and peri-procedural, independent, neurological assessment. Maintenance of proficiency in CAS requires active involvement in surgical/endovascular audit and continuing medical education programmes. These standards should apply in the public and private health-care settings. These guidelines represent the consensus of an intercollegiate committee in order to direct appropriate patient selection to perform CAS. Advances in endovascular technologies and the results of randomised controlled trials will guide future revisions of this document.

1. Previous studies have demonstrated that the resting activity of electrosensory ALLN fibers is modulated by the animal's own respiratory activity and that all fibers innervating a single ampullary cluster are modulated with the same amplitude and phase relationship to ventilation. We demonstrate that ALLN fibers in the skate are modulated in this common-mode manner bilaterally, regardless of receptor group, orientation, or position of the receptor pore on the body surface (Fig. 2). 2. Ascending efferent neurons (AENs), which project to the electrosensory midbrain from the DON, are modulated through a much smaller portion of their dynamic range. AENs give larger responses to an extrinsic local electric field than to the respiratory driving, indicating that a mechanism exists for suppressing ventilatory electrosensory reafference. 3. In paralyzed animals no modulation of resting activity or of responses of extrinsic electric fields could be observed with respect to the animal's respiratory motor commands in the absence of electrosensory reafference. 4. Cells of the dorsal granular ridge (DGR) project to medullary AENs via the DON molecular layer. A majority of proprioceptive DGR neurons are modulated by ventilatory activity, however, in a given fish the modulation is not in the same phase relationship to ventilation among DGR units. 5. The modulation of AENs during respiration was increased following transection of the contralateral ALLN (Fig. 9). Resting activity and responses to excitatory stimuli were inhibited by simultaneous stimulation of the transected contralateral ALLN indicating that a common-mode rejection mechanism is mediated via the commissural interconnections of the DONs.

In personal interviews, people surrendering their dogs and cats to 12 animal shelters in 4 regions of the country discussed their reasons for relinquishing their companion animals and answered questions about their own characteristics and those of their pet. The interviews identified 71 reasons for relinquishment. Personal issues lead the class of reasons for relinquishment of cats and ranked 3rd among those given for relinquishment of dogs. The top 3 health and personal issues cited for giving up cats were allergies of a family member to cats, owner's personal problems, and anew baby. For dogs, the top 3 reasons cited were lack of time for the dog, owner's personal problems, and allergies. Analysis of these health and personal issues suggests that education and counseling before and after acquisition of a pet, as well as the availability of temporary accommodations for pets during times of personal crisis, may reduce relinquishments.

The methylation of N-phenylhydroxylamine (NPHA) with methylarenesulfonates in DMSO gives alkylation of the O atom in contrast to methylation in methanol where N alkylation occurs. The Hammett ρ values indicate that alkylations with N-methylanilines and NPHAs both involve the N atom. The NPHAs show “nominal α-effects” but involve comparison of N atoms with O atoms. The reactivity of the principle component, the zwitterion I, is examined with leaving group studies and comparison with benzyl alkoxide reactivity.

The electrosensory and mechanosensory lateral line systems of fish exhibit many common features in their structural and functional organization, both at the sensory periphery as well as in central processing pathways. These two sensory systems also appear to play similar roles in many behavioral tasks such as prey capture, orientation with respect to external environmental cues, navigation in low-light conditions, and mediation of interactions with nearby animals. In this paper, we briefly review key morphological, physiological, and behavioral aspects of these two closely related sensory systems. We present arguments that the information processing demands associated with spatial processing are likely to be quite similar, due largely to the spatial organization of both systems and the predominantly dipolar nature of many electrosensory and mechanosensory stimulus fields. Demands associated with temporal processing may be quite different, however, due primarily to differences in the physical bases of electrosensory and mechanosensory stimuli (e.g. speed of transmission). With a better sense of the information processing requirements, we turn our attention to an analysis of the functional organization of the associated first-order sensory nuclei in the hindbrain, including the medial octavolateral nucleus (MON), dorsal octavolateral nucleus (DON), and electrosensory lateral line lobe (ELL). One common feature of these systems is a set of neural mechanisms for improving signal-to-noise ratios, including mechanisms for adaptive suppression of reafferent signals. This comparative analysis provides new insights into how the nervous system extracts biologically significant information from dipolar stimulus fields in order to solve a variety of behaviorally relevant problems faced by aquatic animals.