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Disconnection
Terms modified by Disconnection Selected AbstractsNeuronal Disconnection for the Surgical Treatment of Pediatric EpilepsyEPILEPSIA, Issue 2000Hiroyuki Shimizu Summary: The surgical methods and results of disconnective surgery for pediatric epilepsy were retrospectively analyzed. The techniques of neuronal disconnection included multiple subpial resection (MST), corpus callosotomy, and functional hemisphercctomy by disconnection. Of 158 total pediatric operations, disconnective techniques were employed in more than 60% of the cases. MST was applied when the epileptic focus was located in unresectable cortices such as speech or motor areas. MST was also instrumental when the epileptogenic zone was extensive and was widely disseminated, as is often observed in cases of neocortical epilepsy. Of 25 patients who underwent MST, surgical outcomes after > 1 year follow-up showed Engel Class I or II in 10 cases, Class III in 12, and Class IV in 3. No mortality or morbidity was encountered during surgery or postoperatively. Corpus callosotomy was applied to cases of disabling generalized seizures and showed a marked effect in alleviating potentially injurious drop attacks. Of 34 patients with drop attacks, 29 became free from this type of seizure, 4 had infrequent attacks, and only 1 showed no beneficial effect. Postoperative improvement of cognition and speech was recognized in 77% of the cases. We developed a new method of functional hemispherectomy by fiber disconnection and applied this less invasive technique to 23 cases of hemispheric lesions. Of the 17 cases with > 1 year follow-up, 13 were in Class I or II, and 3 in Class III, and 2 in Class IV. Development partially normalized in infants with good seizure outcomes. [source] Synaptic and non-synaptic mechanisms of amygdala recruitment into temporolimbic epileptiform activitiesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2003Julia Klueva Abstract Lateral amygdala (LA) activity during synchronized-epileptiform discharges in temporolimbic circuits was investigated in rat horizontal slices containing the amygdala, hippocampus (Hip), perirhinal (Prh) and lateral entorhinal (LEnt) cortex, through multiple-site extra- and intracellular recording techniques and measurement of the extracellular K+ concentration. Application of 4-aminopyridine (50 µm) induced epileptiform discharges in all regions under study. Slow interictal-like burst discharges persisted in the Prh/LEnt/LA after disconnection of the Hip, seemed to originate in the Prh as shown from time delay analyses, and often preceded the onset of ictal-like activity. Disconnection of the amygdala resulted in de-synchronization of epileptiform discharges in the LA from those in the Prh/LEnt. Interictal-like activity was intracellularly reflected in LA projection neurons as ,-aminobutyric acid (GABA)A/B receptor-mediated synaptic responses, and depolarizing electrogenic events (spikelets) residing on the initial phase of the GABA response. Spikelets were considered antidromically conducted ectopic action potentials generated at axon terminals, as they were graded in amplitude, were not abolished through hyperpolarizing membrane responses (which effectively blocked evoked orthodromic action potentials), lacked a clear prepotential or synaptic potential, were not affected through blockers of gap junctions, and were blocked through remote application of tetrodotoxin at putative target areas of LA projection neurons. Remote application of a GABAB receptor antagonist facilitated spikelet generation. A transient elevation in the extracellular K+ level averaging 3 mm above baseline occurred in conjunction with interictal-like activity in all areas under study. We conclude that interictal-like discharges in the LA/LEnt/Prh spread in a predictable manner through the synaptic network with the Prh playing a leading role. The rise in extracellular K+ may provide a depolarizing mechanism for recruitment of interneurons and generation of ectopic action potentials at axon terminals of LA projection neurons. Antidromically conducted ectopic action potentials may provide a spreading mechanism of seizure activity mediated by diffuse axonal projections of LA neurons. [source] Electrical Disconnection of the Superior Vena Cava from the Right AtriumJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2004VINOD K. JAYAM M.D. [source] Pulmonary Vein Disconnection Using the LocaLisa Three-Dimensional Nonfluoroscopic Catheter Imaging SystemJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2003Laurent Macle M.D. Introduction: Catheter ablation for atrial fibrillation (AF) is associated with prolonged fluoroscopy times. We prospectively evaluated the use of the LocaLisa three-dimensional nonfluoroscopic catheter imaging system with the aim of reducing fluoroscopy times during pulmonary vein (PV) disconnection. Methods and Results: Fifty-two patients with AF (47 men and 5 women, mean age 53 ± 9 years) underwent disconnection of all four PVs guided by a circumferential mapping catheter. The LocaLisa navigation system was used for real-time three-dimensional nonfluoroscopic imaging of the circumferential mapping catheter and ablation catheter electrodes in 26 patients. Procedural parameters were compared with those of a control group consisting of 26 patients in whom only standard fluoroscopy was used. PV disconnection was performed similarly in both groups by circumferential ablation around the ostia, with the endpoint of disconnecting left atrium to PV breakthroughs. The cumulative duration of radiofrequency (RF) energy delivery, procedural time, and fluoroscopy time required for PV disconnection were compared. Successful disconnection was achieved in all PVs, without acute complications. There was no significant difference in cumulative RF energy delivery: 34.8 ± 11.4 minutes for the nonfluoroscopic imaging group versus 38.2 ± 10.5 minutes for the control group. The fluoroscopy time required for disconnection of all four PVs was significantly lower in the LocaLisa group than in the control group: 8.4 ± 4.3 minutes versus 23.7 ± 9.7 minutes (P < 0.0001). There also was a significant difference in the mean time taken for PV disconnection: 46.5 ± 12.0 minutes for the nonfluoroscopic imaging group versus 66.3 ± 18.9 minutes for the control group (P < 0.0001). Conclusion: By allowing continuous three-dimensional monitoring of ablation and mapping catheter position and orientation, the LocaLisa nonfluoroscopic imaging system significantly reduces fluoroscopy and PV disconnection times. (J Cardiovasc Electrophysiol, Vol. 14, pp. 693,697, July 2003) [source] Dissociated Activity and Pulmonary Vein Fibrillation Following Functional Disconnection:PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2003Impact for the Arrhythmogenesis of Focal Atrial Fibrillation The present study sought to investigate the electrophysiological properties of isolated pulmonary veins following successful radiofrequency (RF) catheter ablation in patients with paroxysmal atrial fibrillation (PAF). Overall, 71 pulmonary veins in 37 consecutive patients (age:56 ± 9 years) with recurrent PAF were targeted for RF ablation at the ostial region in order to achieve a complete functional block. Following disconnection, the incidence of dissociated pulmonary vein (PV) activity and its response to orciprenalin were studied. RF ablation abolished conduction in 67 (94%) of 71 potentially arrhythmogenic PVs after a mean of10.7 ± 6.4 RFapplications for each PV. After ablation, spontaneous dissociated automatic activity (9 to 52 beats/min, median 27) was found in 6 out of 67 isolated PVs (left superior:n = 1, left inferior:n = 1, right superior:n = 2, common left PV:n = 2). Slight acceleration (13 to 68 beats/min, median 29) of dissociated PV activity was observed during infusion of orciprenalin. Following isolation, initiation of sustained or nonsustained local fibrillation was recorded in only two cases of the common left sided PV with preceding automatic activity. In one patient PV fibrillation occurred during orciprenalin infusion following a repetitive response to a dissociated automatic rhythm with increasing duration as well as destabilization. In the other patient, PV fibrillation occurred immediately after the occurrence of PV automaticity. Slow dissociated automatic rhythms are detectable within 9% of disconnected PVs. The unique anatomic substrate of common left PVs seem to favor the occurrence of local fibrillation following isolation. The initiation pattern of fibrillation within the isolated PV has pathophysiological implications and underlines the contribution of multiple factors to the onset and sustenance of PAF. (PACE 2003; 26:1363,1370) [source] Participatory Budgeting in Midwestern States: Democratic Connection or Citizen Disconnection?PUBLIC BUDGETING AND FINANCE, Issue 3 2009AIMEE L. FRANKLIN What participation mechanisms connect citizens and city officials? Do they produce valued outcomes? Surveys of elected officials suggest that microlevel mechanisms such as direct citizen contact are more valuable in meeting participation goals than are mechanisms focusing on macrolevel concerns. However, there is a disconnect between perceptions about value and the use of mechanisms. State-level participation requirements and a city manager have little effect on the value of a mechanism. These findings raise some questions: why are microlevel participation mechanisms favored, why do some mechanisms have value even though respondents have little experience with them, and why is there a misalignment between participatory goals and the mechanisms used? [source] Different core beliefs predict paternal and maternal attachment representations in young womenCLINICAL PSYCHOLOGY AND PSYCHOTHERAPY (AN INTERNATIONAL JOURNAL OF THEORY & PRACTICE), Issue 3 2006J. Blissett Core beliefs about the self are hypothesized to be rooted in early interpersonal experiences, particularly with one's family (Young, 1999). This study aimed to assess the relationship between reports of core beliefs and current parental attachment in young women. Two hundred and six young women completed self-report questionnaires to ascertain their cognitive representations of their current attachment to parents (Parental Attachment Questionnaire: Kenny, 1987) and core beliefs (Young Schema Questionnaire: Young, 1998). Regression analyses revealed different predictors of maternal and paternal attachment functioning. Disconnection and rejection beliefs predicted young women's current attachment to their father, whereas the quality of current maternal attachment was predicted by a wider range of dysfunctional beliefs, including disconnection and rejection, impaired autonomy and performance, and impaired limits. The implications of these findings for understanding the relationship between core beliefs and attachment are discussed.,Copyright © 2006 John Wiley & Sons, Ltd. [source] Seeing the phantom: A functional magnetic resonance imaging study of a supernumerary phantom limb,ANNALS OF NEUROLOGY, Issue 6 2009Asaid Khateb PhD Objective Supernumerary phantom limb (SPL) is a rare neurological manifestation where patients with a severe stroke-induced sensorimotor deficit experience the illusory presence of an extra limb that duplicates a real one. The illusion is most often experienced as a somesthetic phantom, but rarer SPLs may be intentionally triggered or seen. Here, we report the case of a left visual, tactile, and intentional SPL caused by right subcortical damage in a nondeluded woman. Methods Using functional magnetic resonance imaging, we investigated the multimodal nature of this phantom, which the patient claimed to be able see, use, and move intentionally. The patient participated in a series of sensorimotor and motor imagery tasks involving the right, the left plegic, and the SPL's hand. Results Right premotor and motor regions were engaged when she imagined that she was scratching her left cheek with her left plegic hand, whereas when she performed the same task with the SPL, additional left middle occipital areas were recruited. Moreover, comparison of responses induced by left cheek (subjectively feasible) versus right cheek scratching (reportedly unfeasible movement) with the SPL demonstrated significant activation in right somesthetic areas. Interpretation These findings demonstrate that intentional movements of a seen and felt SPL activate premotor and motor areas together with visual and sensory cortex, confirming its multimodal dimension and the reliability of the patient's verbal reports. This observation, interpreted for cortical deafferentation/disconnection caused by subcortical brain damage, constitutes a new but theoretically predictable entity among disorders of bodily awareness. Ann Neurol 2009;65:698,705 [source] Cognitive subprocesses and schizophrenia.ACTA PSYCHIATRICA SCANDINAVICA, Issue 2001Objective:,The aim of the study is to demonstrate that deficits of information processing in schizophrenic patients can be isolated with reaction-time (RT) decomposition paradigms. Method:,Three types of visually presented tasks were applied: simple, disjunctive and choice RT-tasks. RT were split into movement latency and time necessary to execute movements. Comparisons of three samples of schizophrenic patients (295.3) with individually matched (age, sex, education and handedness) healthy controls are presented: Sample 1: 10 drug-naive first-onset patients, Sample 2: 10 neuroleptically treated first-onset patients, Sample 3: 10 neuroleptically treated chronically ill patients. Results:,Findings indicate that schizophrenia affects primarily subprocesses in which percepts are translated into appropriate actions (response-selection). Neuroleptic treatment improves processing at this stage but is accompanied by slowing of movement execution. Conclusion:,Response-selection is selectively impaired in first-onset patients. This disturbance, which might be specific for schizophrenia, can be regarded as indication of a disconnection between frontal and posterior areas. [source] Characteristics of creeping discharge along aerial insulated wire under impulse voltages with various wave front durationsELECTRICAL ENGINEERING IN JAPAN, Issue 3 2007Toshiyuki Nishi Abstract When lightning occurs in the neighborhood of outdoor high-voltage distribution lines, creeping discharges propagate along the wire surface from the binding wire tip just after insulator flashover. These discharges give rise to various faults on distribution lines, for instance, disconnection and melting of wire, punch-through breakdown, and so on. We must clarify the creeping discharge characteristics associated with various inductive lightning surges from the viewpoint of safety in high-voltage distribution systems. In our previous paper, it was reported that the lengths and aspects of the negative creeping discharges were influenced by the wave front durations of impulse voltages applied to the central line with a grounded binding wire. The present study was performed to obtain more information on such creeping discharges. This paper describes the distinctive characteristics of a creeping discharge along the insulated wire surface when impulse voltages with various wave front durations are applied to the binding wire. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(3): 29,37, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20430 [source] Service restoration method considering simultaneous disconnection of distributed generators by one-bank fault of distribution systemELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 8 2008Hirotaka Takano Abstract Distributed generators (DGs) such as fuel cells and solar cells are going to be installed in the demand side of distribution systems. The DGs can reduce distribution loss by appropriate allocation. However, there are several problems installing DGs such as service restoration of distribution system with DGs and so on. When one bank fault of distribution substation occurs in distribution system, since DGs are simultaneously disconnected from the system, it is not easy to restore isolated load by one bank switching in distribution substation. Therefore, a service restoration method to determine restoration configuration and restoration procedures (switching procedure from normal configuration to restoration configuration) taking into account simultaneous disconnection of DGs is needed. In this paper, the authors propose a computation method to determine the optimal restoration configuration and the restoration procedure considering simultaneous disconnection of DGs by one bank fault of distribution system. In the proposed algorithm, after all of the restoration configuration candidates are effectively enumerated under the operational constraints, the optimal configuration to restore the isolated load is selected among enumerated configuration candidates. After determining the optimal restoration configuration, the optimal restoration procedures are obtained by greedy algorithm. Numerical simulations are carried out for a real scale system model with 237 sectionalizing switches (configuration candidates are 2237) and 21 DGs (total output is 5250 kW which is 3% of total load) in order to examine the validity of the proposed algorithm. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(8): 44,55, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10133 [source] Posterior Quadrantic Epilepsy Surgery: Technical Variants, Surgical Anatomy, and Case SeriesEPILEPSIA, Issue 8 2007Roy Thomas Daniel Summary:,Objective: Patients with intractable epilepsy due to extensive lesions involving the posterior quadrant (temporal, parietal, and occipital lobes) form a small subset of epilepsy surgery. This study was done with a view to analyze our experience with this group of patients and to define the changes in the surgical technique over the last 15 years. We also describe the microsurgical technique of the different surgical variants used, along with their functional neuroanatomy. Methods: In this series there were 13 patients with a median age of 17 years. All patients had extensive presurgical evaluation that provided concordant evidence localizing the lesion and seizure focus to the posterior quadrant. The objective of the surgery was to eliminate the effect of the epileptogenic tissue and preserve motor and sensory functions. Results: During the course of this study period of 15 years, the surgical procedure performed evolved toward incorporating more techniques of disconnection and minimizing resection. Three technical variants were thus utilized in this series, namely, (i) anatomical posterior quadrantectomy (APQ), (ii) functional posterior quadrantectomy (FPQ), and (iii) periinsular posterior quadrantectomy (PIPQ). After a median follow-up period of 6 years, 12/13 patients had Engel's Class I seizure outcome. Conclusion: The results of surgery for posterior quadrantic epilepsy have yielded excellent seizure outcomes in 92% of the patients in the series with no mortality or major morbidity. The incorporation of disconnective techniques in multilobar surgery has maintained the excellent results obtained earlier with resective surgery. [source] Neuronal Disconnection for the Surgical Treatment of Pediatric EpilepsyEPILEPSIA, Issue 2000Hiroyuki Shimizu Summary: The surgical methods and results of disconnective surgery for pediatric epilepsy were retrospectively analyzed. The techniques of neuronal disconnection included multiple subpial resection (MST), corpus callosotomy, and functional hemisphercctomy by disconnection. Of 158 total pediatric operations, disconnective techniques were employed in more than 60% of the cases. MST was applied when the epileptic focus was located in unresectable cortices such as speech or motor areas. MST was also instrumental when the epileptogenic zone was extensive and was widely disseminated, as is often observed in cases of neocortical epilepsy. Of 25 patients who underwent MST, surgical outcomes after > 1 year follow-up showed Engel Class I or II in 10 cases, Class III in 12, and Class IV in 3. No mortality or morbidity was encountered during surgery or postoperatively. Corpus callosotomy was applied to cases of disabling generalized seizures and showed a marked effect in alleviating potentially injurious drop attacks. Of 34 patients with drop attacks, 29 became free from this type of seizure, 4 had infrequent attacks, and only 1 showed no beneficial effect. Postoperative improvement of cognition and speech was recognized in 77% of the cases. We developed a new method of functional hemispherectomy by fiber disconnection and applied this less invasive technique to 23 cases of hemispheric lesions. Of the 17 cases with > 1 year follow-up, 13 were in Class I or II, and 3 in Class III, and 2 in Class IV. Development partially normalized in infants with good seizure outcomes. [source] Contralateral EEG Slowing and Amobarbital Distribution in Wada Test: An Intracarotid SPECT StudyEPILEPSIA, Issue 2 2000Seung Bong Hong Summary: Purpose: To relate the occurrence of contralateral electroencephalogram slowing (CES) to amobarbital distribution, we performed electroencephalogram (EEG) monitoring and intracarotid single photon emission computed tomography (SPECT) during an intracarotid amobarbital procedure (IAP). Methods: IAP was performed on 22 patients with temporal lobe epilepsy. CES was defined as the occurrence of significant EEG slowing on the contralateral hemisphere (>50% of the ipsilateral hemisphere slowing) after amobarbital injection. To map the distribution of the amobarbital, we injected a mixture of amobarbital and 99m technetium-ethylcysteinate dimer (99m Tc-ECD) into the internal carotid artery and performed a brain SPECT 2 h later. In the SPECT images, regions of interest were determined by ipsilateral and contralateral anterior cerebral artery territories (iACA, cACA), ipsilateral and contralateral middle cerebral artery territories (iMCA, cMCA), and ipsilateral and contralateral posterior cerebral artery territories (iPCA, cPCA), as well as ipsilateral and contralateral anterior and posterior mesial temporal regions (iAMT, cAMT, iPMT, cPMT). The perfusion of amobarbital was interpreted visually in each region. Results: Amobarbital was distributed in the iMCA in all the patients; in the iACA in 20 (90.9%) patients; in the iAMT in 14 (63.5%); and in the iPCA and iPMT in only two (9.1%). CES was observed in 13 (59.1%) patients. Cross-perfusion of amobarbital in limited areas of the cACA were observed in only four of 13 patients. Wada retention memory scores (WRMS) showed no significant difference between the CES- (n = 9) and CES+ (n = 13) groups. Conclusions: Amobarbital rarely perfused the iPCA territory and the iPMT region and was rarely delivered to the contralat-eral hemisphere. The occurrence of CES was not related to the cross-perfusion of amobarbital. CES appears to be produced by a transient functional disconnection from the ipsilateral hemisphere. [source] Synaptic and non-synaptic mechanisms of amygdala recruitment into temporolimbic epileptiform activitiesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2003Julia Klueva Abstract Lateral amygdala (LA) activity during synchronized-epileptiform discharges in temporolimbic circuits was investigated in rat horizontal slices containing the amygdala, hippocampus (Hip), perirhinal (Prh) and lateral entorhinal (LEnt) cortex, through multiple-site extra- and intracellular recording techniques and measurement of the extracellular K+ concentration. Application of 4-aminopyridine (50 µm) induced epileptiform discharges in all regions under study. Slow interictal-like burst discharges persisted in the Prh/LEnt/LA after disconnection of the Hip, seemed to originate in the Prh as shown from time delay analyses, and often preceded the onset of ictal-like activity. Disconnection of the amygdala resulted in de-synchronization of epileptiform discharges in the LA from those in the Prh/LEnt. Interictal-like activity was intracellularly reflected in LA projection neurons as ,-aminobutyric acid (GABA)A/B receptor-mediated synaptic responses, and depolarizing electrogenic events (spikelets) residing on the initial phase of the GABA response. Spikelets were considered antidromically conducted ectopic action potentials generated at axon terminals, as they were graded in amplitude, were not abolished through hyperpolarizing membrane responses (which effectively blocked evoked orthodromic action potentials), lacked a clear prepotential or synaptic potential, were not affected through blockers of gap junctions, and were blocked through remote application of tetrodotoxin at putative target areas of LA projection neurons. Remote application of a GABAB receptor antagonist facilitated spikelet generation. A transient elevation in the extracellular K+ level averaging 3 mm above baseline occurred in conjunction with interictal-like activity in all areas under study. We conclude that interictal-like discharges in the LA/LEnt/Prh spread in a predictable manner through the synaptic network with the Prh playing a leading role. The rise in extracellular K+ may provide a depolarizing mechanism for recruitment of interneurons and generation of ectopic action potentials at axon terminals of LA projection neurons. Antidromically conducted ectopic action potentials may provide a spreading mechanism of seizure activity mediated by diffuse axonal projections of LA neurons. [source] Autonomous power system for island or grid-connected wind turbines in distributed generationEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 7 2008Grzegorz Iwanski Abstract Modern power generation systems for wind turbines are often based on the rotor fed slip-ring machines. Power electronics converter provides the slip power, and also the reactive power for excitation of the generator during standalone operation. This way the isolated load can be supplied even if the grid has failed. Stator voltage in an autonomous operation is controlled using vectorial phase locked loop (PLL) structure; therefore the information about mechanical speed or angular position of the rotor is eliminated from the control method. The second PLL is also used for synchronization of the generated voltage with the grid voltage. Voltages synchronization is necessary for soft connection and protection of the supplied load from the rapid change of the supply voltage phase. The grid-connected doubly fed induction generator (DFIG) can be useful after grid fault; however, the mains outage detection methods are necessary for fast disconnection after grid failures. Copyright © 2008 John Wiley & Sons, Ltd. [source] The Heart of the Matter: An Essay about the Effects of Managed Care on Family Therapy with Children,FAMILY PROCESS, Issue 4 2001Ellen Pulleyblank Coffey Ph.d. This essay is based on a pilot study that examined the effects of managed care on the treatment of children and families, with special attention to community mental health. We embarked on the pilot study to test the accuracy and generalizability of our impression that family therapy and other systemic practices have been marginalized in ordinary clinics and agencies, and to understand the reasons why. We interviewed managed care providers, researchers, family therapy trainers, and clinicians in the Northeast. Our findings led to seven themes that support our impression that, even though there is a consensus about the need for coordinated family-based services, there is a disconnection between state policies, contractual requirements and what is actually occurring at the implementation level. This study suggests that our knowledge of human systems may be in danger of being disqualified and lost, with damaging consequences for the care of children. Yet, as systemic thinkers and practitioners, it is our belief that ethical and effective treatment need not be at odds with care that is cost-efficient. The direction of our future research will be to study whether the involvement of all stakeholders at all levels of planning and training leads to systemic family-based practices that consistently save costs and provide high-quality care. [source] Priming the productivity pump: flood pulse driven trends in suspended algal biomass distribution across a restored floodplainFRESHWATER BIOLOGY, Issue 8 2006DYLAN S. AHEARN Summary 1. Chlorophyll a (Chl a) distribution across a 0.36 km2 restored floodplain (Cosumnes River, California) was analysed throughout the winter and spring flood season from January to June 2005. In addition, high temporal-resolution Chl a measurements were made in situ with field fluorometers in the floodplain and adjacent channel. 2. The primary objectives were to characterise suspended algal biomass distribution across the floodplain at various degrees of connection with the channel and to correlate Chl a concentration and distribution with physical and chemical gradients across the floodplain. 3. Our analysis indicates that periodic connection and disconnection of the floodplain with the channel is vital to the functioning of the floodplain as a source of concentrated suspended algal biomass for downstream aquatic ecosystems. 4. Peak Chl a levels on the floodplain occurred during disconnection, reaching levels as high as 25 ,g L,1. Chl a distribution across the floodplain was controlled by residence time and local physical/biological conditions, the latter of which were primarily a function of water depth. 5. During connection, the primary pond on the floodplain exhibited low Chl a (mean = 3.4 ,g L,1) and the shallow littoral zones had elevated concentrations (mean = 4.6 ,g L,1); during disconnection, shallow zone Chl a increased (mean = 12.4 ,g L,1), but the pond experienced the greatest algal growth (mean = 14.7 ,g L,1). 6. Storm-induced floodwaters entering the floodplain not only displaced antecedent floodplain waters, but also redistributed floodplain resources, creating complex mixing dynamics between parcels of water with distinct chemistries. Incomplete replacement of antecedent floodplain waters led to localised hypoxia in non-flushed areas. 7. The degree of complexity revealed in this analysis makes clear the need for high-resolution spatial and temporal studies such as this to begin to understand the functioning of dynamic and heterogeneous floodplain ecosystems. [source] Venous needle dislodgement during hemodialysis: An unresolved risk of catastrophic hemorrhageHEMODIALYSIS INTERNATIONAL, Issue 1 2005S. Sandroni Venous line disconnection or needle dislodgement during hemodialysis with resultant hemorrhage is a potentially lethal event. The risk is compounded by the frequent failure of standard dialysis machines to detect the event, as blood flow through the venous needle typically creates enough back pressure to prevent venous pressure alarms even if the needle is completely out of the patient's AV access. Manufacturers are well aware of the risk and device literature contains specific warnings about it. The FDA publishes reports on its website about these events; so far this year there have been seven reported events with five deaths. Informal sources indicate that the actual (unreported) occurrence is much more frequent; we are aware of four additional events within our region alone. Efforts to reduce the risk include protocols requiring the access needles to always be visible, and use of enuresis detection devices. Anecdotal experience with these efforts suggests they are not highly effective. Protocols requiring documentation of more frequent needle site checks or alternate methods of securing the needles have not been formally evaluated. However, such efforts do not address the primary problem: there is a need for an engineered solution to this problem. Requirements for such a solution include: reliable detection of needle position and blood flow discrepancies, a useful alarm, and feedback to stop the blood pump. Persistence of this problem raises issues of regulatory oversight. [source] Noninvasive dynamic imaging of seizures in epileptic patientsHUMAN BRAIN MAPPING, Issue 12 2009Louise Tyvaert Abstract Epileptic seizures are due to abnormal synchronized neuronal discharges. Techniques measuring electrical changes are commonly used to analyze seizures. Neuronal activity can be also defined by concomitant hemodynamic and metabolic changes. Simultaneous electroencephalogram (EEG)-functional MRI (fMRI) measures noninvasively with a high-spatial resolution BOLD changes during seizures in the whole brain. Until now, only a static image representing the whole seizure was provided. We report in 10 focal epilepsy patients a new approach to dynamic imaging of seizures including the BOLD time course of seizures and the identification of brain structures involved in seizure onset and discharge propagation. The first activation was observed in agreement with the expected location of the focus based on clinical and EEG data (three intracranial recordings), thus providing validity to this approach. The BOLD signal preceded ictal EEG changes in two cases. EEG-fMRI may detect changes in smaller and deeper structures than scalp EEG, which can only record activity form superficial cortical areas. This method allowed us to demonstrate that seizure onset zone was limited to one structure, thus supporting the concept of epileptic focus, but that a complex neuronal network was involved during propagation. Deactivations were also found during seizures, usually appearing after the first activation in areas close or distant to the activated regions. Deactivations may correspond to actively inhibited regions or to functional disconnection from normally active regions. This new noninvasive approach should open the study of seizure generation and propagation mechanisms in the whole brain to groups of patients with focal epilepsies. Hum Brain Mapp, 2009. © 2009 Wiley-Liss, Inc. [source] Fair Value Accounting and the Financial Crisis: Messenger or Contributor?,ACCOUNTING PERSPECTIVES, Issue 3 2009Michel L. Magnan ABSTRACT This commentary discusses how fair value accounting (FVA) affects the nature of financial reporting, especially for financial institutions that were deeply affected by the 2007-9 financial crisis. Toward that end, I address four questions. First, I review FVA's role in financial reporting, emphasizing its development over time. While the commentary's focus is on the interface between financial instruments and FVA, its reach extends well beyond financial instruments. Thereafter, I discuss the measurement and valuation challenges that arise from the use of FVA in financial reporting. Then, I analyze the evidence, analytical and empirical, on the role that FVA may have played in the financial crisis of 2007-9. Since, to some extent, the crisis is still unfolding, there is limited yet very insightful empirical evidence on this issue. The evidence does suggest that FVA, in combination with its use by regulators, may have severely undermined the financial condition of some institutions. The effect was amplified for institutions holding assets in markets that saw their liquidity dry up during the crisis. In other words, FVA may have amplified the crisis. Finally, I discuss some implications that we can draw from the crisis about the merits and risks underlying FVA. For instance, I conclude that, in a search for relevance, the use of FVA in financial reporting may accelerate its disconnection from a firm's business reality. [source] Dismantling the Built Drawing: Working with Mood in Architectural DesignINTERNATIONAL JOURNAL OF ART & DESIGN EDUCATION, Issue 1 2010Randall TealArticle first published online: 15 MAR 2010 From the late Middle Ages onward an emphasis on the rational and the technical aspects of design and design drawing gained hold of architectural practice. In this transformation, the phenomenon of mood has been frequently overlooked or seen as something to be added on to a design; yet the fundamental grounding of mood, as described in Martin Heidegger's philosophy, is anything but secondary to our experience of the world. In fact, other facilities such as embodied experience, tactile and spatial awareness, and temporal perception all spring from the basic encounter with mood. In this article I describe how a lack of attunement to, and limited ability with, the various manifestations of mood perpetuates a disconnection between the architectural drawing and real buildings. I argue that as long as educational frameworks relegate the emotional and experiential to the place of a supplement, then our design processes will continue to unconsciously promote environments of thinness and superficiality. [source] Understanding postorganic fresh fruit and vegetable consumers at participatory farmers' markets in Ireland: reflexivity, trust and social movementsINTERNATIONAL JOURNAL OF CONSUMER STUDIES, Issue 5 2006Oliver Moore Abstract This paper examines how trusting relations between consumers and vendors of organic fresh fruits and vegetables (FFVs) in a particular type of farmers' market (FM) in Ireland are established and maintained, and what the implications of this are. First, the food system is outlined, and then its attendant problems. These problems have led to various solutions, two of which are organic food and FMs. Then, the growth in these two areas is outlined, as is the accompanying growth in the academic literature on these two areas, some of which overlaps. Various pressures, including in particular the increasing distance food travels and disconnected stallholders and products at the FM, are suggested. In light of this, a need to apply an understanding of the reflexive consumer, trust and social movements is suggested. It is found that the consumers interviewed act reflexively by choosing to go to these FMs. They prioritize the trusting relationships built up through repeated personal contact at these FMs over and above organic certification. Along with and as part of this, they prioritize local, fresh, seasonal ,chemical-free' FFVs over and above imported certified organic produce. Various aspects of collective identity formation, including modes of behaviour, objects and stories, and language, are involved in this process. These elements, to some extent, act as a buffer against the pressures of distance and disconnection. Along with this, the essential meaning of the word organic is, in this particular context, reconstructed to include various socio-environmental values missing from some certified organic produce. The word postorganic is suggested. The main methodologies used are semistructured in-depth interviews and participant observation. [source] Correcting misconceptions about the development of social work in China: a response to Hutchings and TaylorINTERNATIONAL JOURNAL OF SOCIAL WELFARE, Issue 1 2008Cunfu Jia Hutchings and Taylor, in their article entitled ,Defining the profession? Exploring an international definition of social work in the China context'[International Journal of Social Welfare 16: 381,389], no doubt had good intentions in offering their account of the development of social work in China, as the opening and concluding sections of the article show. Within the text, however, their critique of contemporary social work in China is, in my opinion, unfair in relation to, among other things, (i) the undemocratic nature of the Chinese political system, which they say hinders the development of social work in China; (ii) the ideology of the Communist Party, the government, and traditional Chinese culture, which they say are at odds with Western social work's value system and methodology; thus concluding that (iii) it is doubtful whether social work development in China could integrate with that of the international community. In this response, I comment on (i) the information base of the authors; (ii) the disconnection between their conceptualisation and historical facts; and (iii) their use of the international definition of social work. [source] Reduced Fluoroscopy During Atrial Fibrillation Ablation: Benefits of Robotic Guided NavigationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2010DANIEL STEVEN M.D. Reduced Fluoroscopy in PVI Using RN.,Background: Recently, a nonmagnetic robotic navigation system (RN, Hansen-SenseiÔ) has been introduced for remote catheter manipulation. Objective: To investigate the influence of RN combined with intuitive 3-dimensional mapping on the fluoroscopy exposure to operator and patient during pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) in a prospective randomized trial. Methods: Sixty patients were randomly assigned to undergo PVI either using a RN guided (group 1; n = 30, 20 male, 62 ± 7.7 years) or conventional ablation approach (group 2; n = 30, 14 male, 61 ± 7.6 years). A 3-dimensional mapping system (NavXÔ) was used in both groups. Results: Electrical disconnection of the ipsilateral pulmonary veins (PVs) was achieved in all patients. Use of RN significantly lowered the overall fluoroscopy time (9 ± 3.4 vs 22 ± 6.5 minutes; P < 0.001) and reduced the operator's fluoroscopy exposure (7 ± 2.1 vs 22 ± 6.5 minutes; P < 0.001). The difference in fluoroscopy duration between both groups was most pronounced during the ablation part of the procedure (3 ± 2.4 vs 17 ± 6.3 minutes; P < 0.001). The overall procedure duration tended to be prolonged using RN without reaching statistical significance (156 ± 44.4 vs 134 ± 12 minutes, P = 0.099). No difference regarding outcome was found during a midterm follow-up of 6 months (AF freedom group 1 = 73% vs 77% in group 2 [P = 0.345]). Conclusion: The use of RN for PVI seems to be effective and significantly reduces overall fluoroscopy time and operator's fluoroscopy exposure without affecting mid-term outcome after 6-month follow-up. (J Cardiovasc Electrophysiol, Vol. 21, pp. 6,12, January 2010) [source] Fibrillating Areas Isolated within the Left Atrium after Radiofrequency Linear Catheter AblationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2006THOMAS ROSTOCK M.D. Introduction: Nonpulmonary vein sources have been implicated as potential drivers of atrial fibrillation (AF). This observational study describes regions of fibrillating atrial tissue isolated inadvertently from the left atrium (LA) following linear catheter ablation for AF. Methods and Results: We report four patients with persistent/permanent AF who underwent pulmonary vein isolation with additional linear lesions and who presented with recurrent AF (mean AF cycle length [AFCL] 175,270 ms). Further catheter ablation resulted in the inadvertent electrical isolation of significant areas of the LA in which AF persisted at the same AFCL as was measured prior to disconnection, despite the restoration of sinus rhythm (SR) in all other left and right atrial areas, strongly suggesting that these islands were driving the remaining atria into fibrillation. The disconnected areas were located in the lateral LA, including the left atrial appendage (LAA) in three patients (limited to the LAA in one) and in the posterior LA in one patient. These isolated fibrillating regions represented 15,24% of the global LA surface, as estimated by electroanatomic mapping. Conclusion: Fibrillation can be maintained within electrically isolated regions of the LA following catheter ablation of AF, demonstrating the importance of atrial drivers in the maintenance of AF. Further mapping of these drivers is needed to characterize their mechanism and thereby allow for a more specific ablation strategy. [source] Ablation of Focally Induced Atrial Fibrillation:JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2004Selective or Extensive? Introduction: Focally induced atrial fibrillation (AF) often is due to ectopic activity in the pulmonary veins (PV). Although initial approaches were aimed at ablating only the ectopic foci, more extensive ablation approaches have evolved that isolate all PVs empirically and/or create circumferential ablation lines in the left atrium (LA). These techniques last longer and may be associated with more risks. We retrospectively evaluated the outcome and risks of ablation for focally induced AF in a single-center patient population. Methods and Results: We report on 47 patients (32 men and 15 women; age 47 ± 10 years) in whom 52 ablations were performed. In 19 patients (22 sessions), ablation was directed at the site(s) of overt ectopic activity ("selective" group), whereas in 28 patients (30 sessions) without sufficient ectopy to determine the culprit PV a mean of 3.5 PVs were empirically targeted for bidirectional disconnection from the LA ("extensive" group). On a preprocedural Holter recording, the "selective" group had significantly more isolated atrial ectopy (3,276 ± 2,933 vs 620 ± 937 beats/24 hours) and runs of atrial tachycardia (330 ± 202 vs 53 ± 87 runs/24 hours) than the "extensive" group (P < 0.01 for both). Only 11% had persistent AF before ablation. Acute procedural success was 81% (elimination of all ectopy) and 83%, respectively (bidirectional and fully circumferential isolation of all targeted PVs). Procedure and fluoroscopy times were significantly shorter in the "selective" group. There were no major complications, but 7 minor complications and 2 acute PV stenoses > 50% in the 30 "extensive" procedures were observed. Mean follow-up was 8.4 ± 8.5 months (median 6.9). Kaplan-Meier analysis, excluding recurrences during only the first month ("delayed cure"), showed AF recurrence in 45% after 6 months and in 55% after 1 year. Outcome was not dependent on ablation approach ("selective" or "extensive") nor was time to first AF (22 ± 64 days and 30 ± 69 days). AF recurrence tended to be higher in patients with larger LA (P = 0.08), underlying heart disease or hypertension (P = 0.08), and those "extensive" patients in whom not all 4 PVs were targeted (P = 0.07). Conclusion: Trigger-directed ablation for focally induced AF is associated with a relatively high recurrence rate during follow-up. Apart from recurrence of the ectopic trigger, this may point to underlying structural changes in the atrial substrate not addressed by the ablation. Prospective evaluation of the risk-to-benefit profile of any technique (selective, extensive, including linear lines) is required. (J Cardiovasc Electrophysiol, Vol. 15, pp. 200-205, February 2004) [source] Pulmonary Vein Disconnection Using the LocaLisa Three-Dimensional Nonfluoroscopic Catheter Imaging SystemJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2003Laurent Macle M.D. Introduction: Catheter ablation for atrial fibrillation (AF) is associated with prolonged fluoroscopy times. We prospectively evaluated the use of the LocaLisa three-dimensional nonfluoroscopic catheter imaging system with the aim of reducing fluoroscopy times during pulmonary vein (PV) disconnection. Methods and Results: Fifty-two patients with AF (47 men and 5 women, mean age 53 ± 9 years) underwent disconnection of all four PVs guided by a circumferential mapping catheter. The LocaLisa navigation system was used for real-time three-dimensional nonfluoroscopic imaging of the circumferential mapping catheter and ablation catheter electrodes in 26 patients. Procedural parameters were compared with those of a control group consisting of 26 patients in whom only standard fluoroscopy was used. PV disconnection was performed similarly in both groups by circumferential ablation around the ostia, with the endpoint of disconnecting left atrium to PV breakthroughs. The cumulative duration of radiofrequency (RF) energy delivery, procedural time, and fluoroscopy time required for PV disconnection were compared. Successful disconnection was achieved in all PVs, without acute complications. There was no significant difference in cumulative RF energy delivery: 34.8 ± 11.4 minutes for the nonfluoroscopic imaging group versus 38.2 ± 10.5 minutes for the control group. The fluoroscopy time required for disconnection of all four PVs was significantly lower in the LocaLisa group than in the control group: 8.4 ± 4.3 minutes versus 23.7 ± 9.7 minutes (P < 0.0001). There also was a significant difference in the mean time taken for PV disconnection: 46.5 ± 12.0 minutes for the nonfluoroscopic imaging group versus 66.3 ± 18.9 minutes for the control group (P < 0.0001). Conclusion: By allowing continuous three-dimensional monitoring of ablation and mapping catheter position and orientation, the LocaLisa nonfluoroscopic imaging system significantly reduces fluoroscopy and PV disconnection times. (J Cardiovasc Electrophysiol, Vol. 14, pp. 693,697, July 2003) [source] Pacing in Right Ventricular Dysplasia after Disconnection SurgeryJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2000CHUEN TANG M.B.B.S. Pacing in Right Ventricular Dysplasia. This report describes a 33-year-old patient with arrhythmogenic right ventricular (RV) dysplasia who had a dual chamber pacemaker implanted at age 23 years for drug-induced bradycardia. Pacing was continued after right ventricular free-wall disconnection (RVFVVD) at age 24 years. Her pacemaker was not replaced after battery depletion 7 years later. She presented the following year in severe right-sided heart failure. Her old pacemaker generator was replaced. This was followed by rapid resolution of her clinical failure and return to a full, active, physical lifestyle. This observation suggests the potential benefit of dual chamber pacing in patients with RV dysplasia after RVFWD. [source] Altering women's relationships with food: A relational, developmental approachJOURNAL OF CLINICAL PSYCHOLOGY, Issue 11 2001Margo Maine Eating disorders, ranging from body-image distortions to full-blown anorexia nervosa and bulimia nervosa, reflect developmental issues and significant deficits in feelings of self-efficacy. The relational model, an outgrowth of theoretical work specific to the psychology of women, is an appropriate treatment approach. This model appreciates the social context and pressures that foster disconnection from the self and helps the woman to reconnect with self and others, decreasing the need for obsessive control over food and weight. Treatment emphasizes empathy, connection, mutuality, and authenticity and views disconnections and disruptions as the predisposing, precipitating, and perpetuating factors related to eating disorders. The client,therapist relationship is central to this model as demonstrated by a case illustration. © 2001 John Wiley & Sons, Inc. J Clin Psychol/In Session 57: 1301,1310, 2001. [source] | ||||||||||||||||||||||||||||||||||||||||||||||