Cardiopulmonary support and extracorporeal membrane oxygenation for cardiac assist.

BACKGROUND: Use of cardiopulmonary bypass for emergency resuscitation is not new. In fact, John Gibbon proposed this concept for the treatment of severe pulmonary embolism in 1937. Significant progress has been made since, and two main concepts for cardiac assist based on cardiopulmonary bypass have emerged: cardiopulmonary support (CPS) and extracorporeal membrane oxygenation (ECMO). The objective of this review is to summarize the state of the art in these two technologies. METHODS: Configuration of CPS is now fairly standard. A mobile cart with relatively large wheels allowing for easy transportation carries a centrifugal pump, a back-up battery with a charger, an oxygen cylinder, and a small heating system. Percutaneous cannulation, pump-driven venous return, rapid availability, and transportability are the main characteristics of a CPS system. Cardiocirculatory arrest is a major predictor of mortality despite the use of CPS. In contrast, CPS appears to be a powerful tool for patients in cardiogenic shock before cardiocirculatory arrest, requiring some type of therapeutic procedures, especially repair of anatomically correctable problems or bridging to other mechanical circulatory support systems such as ventricular assist devices. CPS is in general not suitable for long-term applications because of the small-bore cannulas, resulting in significant pressure gradients and eventually hemolysis. RESULTS: In contrast, ECMO can be designed for longer-term circulatory support. This requires large-bore cannulas and specifically designed oxygenators. The latter are either plasma leakage resistent (true membranes) or relatively thrombo-resistant (heparin coated). Both technologies require oxygenator changeovers although the main reason for this is different (clotting for the former, plasma leakage for the latter). Likewise, the tubing within a roller pump has to be displaced and centrifugal pump heads have to be replaced over time. ECMO is certainly the first choice for a circulatory support system in the neonatal and pediatric age groups, where the other assist systems are too bulky. ECMO is also indicated for patients improving on CPS. Septic conditions are, in general, considered as contraindications for ECMO. CONCLUSIONS: Ease of availability and moderate cost of cardiopulmonary bypass-based cardiac support technologies have to be balanced against the significant immobilization of human resources, which is required to make them successful.

Redox dysregulation in schizophrenia : implication for oligodendrocyte maturation and structural connectivity

Schizophrenia, which results from an interaction between gene and environmental factors, is a psychiatric disorder characterized by reality distortion. The clinical symptoms, which are generally diagnosed in late adolescence or early adulthood, partly derive from altered brain connectivity especially in prefrontal cortex. Disruption of neuronal networks implies oligodendrocyte and myelin abnormalities in schizophrenia pathophysiology. The mechanisms of these impairments are still unclear. Converging evidences indicate a role of redox dysregulation, generated by an imbalance between pro-oxidants and antioxidant defense mechanisms, in the development of schizophrenia pathophysiology. In particular, genetic and biochemical data indicate impaired synthesis of glutathione, the main cellular antioxidant and redox regulator. As oligodendrocyte maturation is dependent on redox state, we evaluated whether abnormal redox control could contribute to oligodendrocyte and myelin impairments in schizophrenia. We found that glutathione in prefrontal cortex of early psychosis patients and control subjects positively correlated with white matter integrity. We then further explored the interplay between glutathione and myelin using a translational approach. Our data showed that in mice with genetically impaired glutathione synthesis, oligodendrocyte late maturation as well as myelination was delayed in the anterior cingulate cortex. Specifically, oligodendrocyte number and myelin levels were lowered at peripubertal age, coincident in time with the peak of myelin- related gene expression during normal brain development. These data suggest that early adolescence is a vulnerable developmental period during which an adequate redox control is required for oligodendrocyte maturation and active myelination process. Consistently, oxidative stress mediated by psychosocial stress also delayed myelination in peripubertal mice. At cellular levels, impaired glutathione synthesis altered oligodendrocyte development at several levels. Using oligodendrocyte progenitor cells cultures, our data showed that glutathione deficiency was associated with (i) cell cycle arrest and a reduction in oligodendrocyte proliferation, and (ii) an impairment in oligodendrocyte maturation. Abnormal oligodendrocyte proliferation was mediated by upregulation of Fyn kinase activity. Consistently, under oxidative stress conditions, we observed abnormal regulation of Fyn kinase in fibroblasts of patients deficient in glutathione synthesis. Together, our data support that a redox dysregulation due to glutathione deficit could underlie myelination impairment in schizophrenia, possibly mediated by dysregulated Fyn pathway. Better characterization of Fyn mechanisms would pave the way towards new drug targets. -- La schizophrénie est une maladie psychiatrique qui se définit par une distorsion de la perception de la réalité. Les symptômes cliniques sont généralement diagnostiqués durant l'adolescence ou au début de l'âge adulte et proviennent de troubles de la connectivité, principalement au niveau du cortex préfrontal. Les dysfonctionnements des réseaux neuronaux impliquent des anomalies au niveau des oligodendrocytes et de la myéline dans la pathophysiologie de la schizophrénie. Les mécanismes responsables des ces altérations restent encore mal compris. Dans le développement de la schizophrénie, des évidences mettent en avant un rôle de la dérégulation rédox, traduit par un déséquilibre entre facteurs pro-oxydants et défenses antioxydantes. Des données génétiques et biochimiques indiquent notamment un défaut de la synthèse du glutathion, le principal antioxydant et rédox régulateur des cellules. Etant donné que la maturation des oligodendrocytes est dépendante de l'état rédox, nous avons regardé si une dérégulation rédox contribue aux anomalies de la myéline dans le cadre de la schizophrénie. Dans le cortex préfrontal des sujets contrôles et des patients en phase précoce de psychose, nous avons montré que le glutathion était positivement associé à l'intégrité de matière blanche. Afin d'explorer plus en détail la relation entre le glutathion et la myéline, nous avons mené une étude translationnelle. Nos résultats ont montré que des souris ayant un déficit de la synthèse du glutathion présentaient un retard dans les processus de maturation des oligodendrocytes et de la myélinisation dans le cortex cingulaire antérieure. Plus précisément, le nombre d'oligodendrocytes et le taux de myéline étaient uniquement diminués durant la période péripubertaire. Cette même période correspond au pic de l'expression des gènes en lien avec la myéline. Ces données soulignent le fait que l'adolescence est une période du développement particulièrement sensible durant laquelle un contrôle adéquat de l'état rédox est nécessaire aux processus de maturation des oligodendrocytes et de myélinisation. Ceci est en accord avec la diminution de myéline observée suite à un stress oxydatif généré par un stress psychosocial. Au niveau cellulaire, un déficit du glutathion affecte le développement des oligodendrocytes à différents stades. En effet, dans des cultures de progéniteurs d'oligodendrocytes, nos résultats montrent qu'une réduction du taux de glutathion était associée à (i) un arrêt du cycle cellulaire ainsi qu'une diminution de la prolifération des oligodendrocytes, et à (ii) des dysfonctionnements de la maturation des oligodendrocytes. Par ailleurs, au niveau moléculaire, les perturbations de la prolifération étaient générées par une augmentation de l'activité de la kinase Fyn. Ceci est en accord avec la dérégulation de Fyn observée dans les fibroblastes de patients ayant une déficience en synthèse du glutathion en condition de stress oxydatif. Les résultats de cette thèse soulignent qu'une dérégulation rédox induite par un déficit en glutathion peut contribuer aux anomalies des oligodendrocytes et de la myéline via le dysfonctionnement des voies de signalisation Fyn. Une recherche plus avancée de l'implication de Fyn dans la maladie pourrait ouvrir la voie à de nouvelles cibles thérapeutiques.

Perspectives of auto-correcting lens distortions in mosaic-based underwater navigation

When unmanned underwater vehicles (UUVs) perform missions near the ocean floor, optical sensors can be used to improve local navigation. Video mosaics allow to efficiently process the images acquired by the vehicle, and also to obtain position estimates. We discuss in this paper the role of lens distortions in this context, proving that degenerate mosaics have their origin not only in the selected motion model or in registration errors, but also in the cumulative effect of radial distortion residuals. Additionally, we present results on the accuracy of different feature-based approaches for self-correction of lens distortions that may guide the choice of appropriate techniques for correcting distortions

Pattern recognition of sleep in rodents using piezoelectric signals generated by gross body movements.

Current research on sleep using experimental animals is limited by the expense and time-consuming nature of traditional EEG/EMG recordings. We present here an alternative, noninvasive approach utilizing piezoelectric films configured as highly sensitive motion detectors. These film strips attached to the floor of the rodent cage produce an electrical output in direct proportion to the distortion of the material. During sleep, movement associated with breathing is the predominant gross body movement and, thus, output from the piezoelectric transducer provided an accurate respiratory trace during sleep. During wake, respiratory movements are masked by other motor activities. An automatic pattern recognition system was developed to identify periods of sleep and wake using the piezoelectric generated signal. Due to the complex and highly variable waveforms that result from subtle postural adjustments in the animals, traditional signal analysis techniques were not sufficient for accurate classification of sleep versus wake. Therefore, a novel pattern recognition algorithm was developed that successfully distinguished sleep from wake in approximately 95% of all epochs. This algorithm may have general utility for a variety of signals in biomedical and engineering applications. This automated system for monitoring sleep is noninvasive, inexpensive, and may be useful for large-scale sleep studies including genetic approaches towards understanding sleep and sleep disorders, and the rapid screening of the efficacy of sleep or wake promoting drugs.

3-d residual eddy current field characterisation: applied to diffusion weighted magnetic resonance imaging.

Clinical use of the Stejskal-Tanner diffusion weighted images is hampered by the geometric distortions that result from the large residual 3-D eddy current field induced. In this work, we aimed to predict, using linear response theory, the residual 3-D eddy current field required for geometric distortion correction based on phantom eddy current field measurements. The predicted 3-D eddy current field induced by the diffusion-weighting gradients was able to reduce the root mean square error of the residual eddy current field to ~1 Hz. The model's performance was tested on diffusion weighted images of four normal volunteers, following distortion correction, the quality of the Stejskal-Tanner diffusion-weighted images was found to have comparable quality to image registration based corrections (FSL) at low b-values. Unlike registration techniques the correction was not hindered by low SNR at high b-values, and results in improved image quality relative to FSL. Characterization of the 3-D eddy current field with linear response theory enables the prediction of the 3-D eddy current field required to correct eddy current induced geometric distortions for a wide range of clinical and high b-value protocols.

Genetic and environmental effects on early life-history traits in salmonids

Les changements environnementaux, tels la température ou les maladies infectieuses, peuvent influencer l'évolution en induisant de la sélection, mais ceci à la seule condition qu'il y ait assez de diversité génétique pour les traits en question ou pour l'expression plastique de ces traits. Au cours cette thèse, nous avons étudié l'effet de potentielles pressions environnementales sur différents phénotypes de trois représentants des sous familles des salmonidés: l'ombre commun (Thymallus thymallus; Thymallinae), la truite de rivière {Salmo trutta; Salmoninae) et le corégone Coregonus palaea (Coregoninae). Les salmonidés se prêtent particulièrement bien à ce type d'expériences car étant hautement sensibles aux conditions environnementales, ils montrent une large variabilité dans leurs traits morphologiques, comportementaux ainsi que d'histoire de vie, tout en bénéficiant d'un large intérêt général. Nous avons testé si le sexe de l'ombre commun pouvait être modifié par la température, ce qui pourrait ainsi expliquer un changement abrupte de sex ratio observé dans l'une des plus grandes populations de Suisse. Nous n'avons trouvé aucun indice permettant de conclure que la température puisse induire ce changement chez l'ombre commun ou chez la truite de rivière. De plus nous avons étudié la plasticité de développement ainsi que d'éclosion, et avons observé des différences entre familles ainsi qu'entre populations. Alors que ces différences comportementales entre populations suggéraient une adaptation aux conditions environnementales locales, cette prédiction n'a pas été confirmée par une expérience de transplantation réciproque d'embryons entre cinq rivières de la même région. Cette étude a montré que les embryons ne survivaient pas mieux dans leur rivière d'origine, indiquant donc une absence d'adaptation locale. Nous avons aussi montré que la mortalité embryonnaire était influencée autant par des "bons gènes" que par des "gènes compatibles", que la qualité des mâles pouvait être signalée par leur coloration, et que le fait d'élever des poissons dans une pisciculture pouvait aboutir a des relations contre-intuitives entre la coloration des mâles et la qualité de leur jeunes. Nos résultats contribuent ainsi à une meilleure compréhension de l'effet de diverses pressions environnementales sur la morphologie, le comportement ou les traits d'histoire de vie chez les salmonidés. - Environmental changes, such as changes in temperatures or infection levels, can induce selection and drive evolution if there is sufficient genetic variation for the traits or the plasticity in trait expression. In this thesis, we investigated the influence of potential environmental stressors on various phenotypes in representatives of the three salmonid subfamilies: the European grayling (Thymallus thymallus; Thymallinae), the brown trout (,Salmo trutta; Salmoninae), and the whitefish Coregonus palaea (Coregoninae). Salmonids are ideal study species, as they seem sensitive to changing environmental conditions, show considerable variability in morphological, behavioral, and life history traits, and are of broad public interest. We investigated whether temperature-induced sex reversal could explain the sex-ratio distortion found in one of Switzerland's largest grayling populations. We found no evidence of temperature-induced sex reversal in either graylings or brown trout. We also examined plasticity in embryo development and the timing of hatching. We found variation at the level of family and population. Although behavioral differences between populations suggested adaptation to local environmental conditions, no indications of local adaptation could be found in reciprocal transplant experiments carried out over five rivers in the same region. We also demonstrate that embryo development and viability is influenced by 'good genes' and 'compatible genes', that the genetic quality of sires can be signaled by their grey coloration, and that raising larvae in a hatchery environment can produce counter-intuitive relationships between male phenotypes and offspring viability. Our results contribute to the understanding of how changing environmental conditions affect the phenotypes and the heritability of early life-history traits in salmonids.

Early pattern recognition in severe perinatal asphyxia: a prospective MRI study.

On the basis of MRI examinations in 88 neonates and infants with perinatal asphyxia, we defined 6 different patterns on T2-weighted images: pattern A--scattered hyperintensity of both hemispheres of the telencephalon with blurred border zones between cortex and white matter, indicating diffuse brain injury; pattern B--parasagittal hyperintensity extending into the corona radiata, corresponding to the watershed zones; pattern C--hyper- and hypointense lesions in thalamus and basal ganglia, which relate to haemorrhagic necrosis or iron deposition in these areas; pattern D--periventricular hyperintensity, mainly along the lateral ventricles, i.e. periventricular leukomalacia (PVL), originating from the matrix zone; pattern E--small multifocal lesions varying from hyper--to hypointense, interpreted as necrosis and haemorrhage; pattern F--periventricular centrifugal hypointense stripes in the centrum semiovale and deep white matter of the frontal and occipital lobes. Contrast was effectively inverted on T1-weighted images. Patterns A, B and C were found in 17%, 25% and 37% of patients, and patterns D, E and F in 19%, 17% and 35%, respectively. In 49 patients a combination of patterns was observed, but 30% of the initial images were normal. At follow-up, persistent abnormalities were seen in all children with patterns A and D, but in only 52% of those with pattern C. Myelination was retarded most often in patients with diffuse brain injury and PVL (patterns A and D).

Adaptation to experimental alterations of the operational sex ratio in populations of Drosophila melanogaster.

Theory predicts that males adapt to sperm competition by increasing their investment in testis mass to transfer larger ejaculates. Experimental and comparative data support this prediction. Nevertheless, the relative importance of sperm competition in testis size evolution remains elusive, because experiments vary only sperm competition whereas comparative approaches confound it with other variables, in particular male mating rate. We addressed the relative importance of sperm competition and male mating rate by taking an experimental evolution approach. We subjected populations of Drosophila melanogaster to sex ratios of 1:1, 4:1, and 10:1 (female:male). Female bias decreased sperm competition but increased male mating rate and sperm depletion. After 28 generations of evolution, males from the 10:1 treatment had larger testes than males from other treatments. Thus, testis size evolved in response to mating rate and sperm depletion, not sperm competition. Furthermore, our experiment demonstrated that drift associated with sex ratio distortion limits adaptation; testis size only evolved in populations in which the effect of sex ratio bias on the effective population size had been compensated by increasing the numerical size. We discuss these results with respect to reproductive evolution, genetic drift in natural and experimental populations, and consequences of natural sex ratio distortion.

Spatial Hyperschematia without Spatial Neglect after Insulo-Thalamic Disconnection.

Different spatial representations are not stored as a single multipurpose map in the brain. Right brain-damaged patients can show a distortion, a compression of peripersonal and extrapersonal space. Here we report the case of a patient with a right insulo-thalamic disconnection without spatial neglect. The patient, compared with 10 healthy control subjects, showed a constant and reliable increase of her peripersonal and extrapersonal egocentric space representations - that we named spatial hyperschematia - yet left her allocentric space representations intact. This striking dissociation shows that our interactions with the surrounding world are represented and processed modularly in the human brain, depending on their frame of reference.

Caval collapse during cardiopulmonary bypass: a reproducible bench model.

OBJECTIVES: During open heart surgery, so-called atrial chatter, a phenomenon due to right atria and/or caval collapse, is frequently observed. Collapse of the cava axis during cardiopulmonary bypass (CPB) limits venous drainage and may result downstream in reduced pump flow on (lack of volume) and upstream in increased after-load (stagnation), which in turn may both result in reduced or even inadequate end-organ perfusion. The goal of this study was to reproduce venous collapse in the flow bench. METHODS: In accordance with literature for venous anatomy, a caval tree system is designed (polyethylene, thickness 0.061 mm), which receives venous inflow from nine afferent veins. With water as medium and a preload of 4.4 mmHg, the system has an outflow of 4500 ml/min (Scenario A). After the insertion of a percutaneous venous cannula (23-Fr), the venous model is continuously served by the afferent branches in a venous test bench and venous drainage is augmented with a centrifugal pump (Scenario B). RESULTS: With gravity drainage (siphon: A), spontaneously reversible atrial chatter can be generated in reproducible fashion. Slight reduction in the outflow diameter allows for generation of continuous flow. With augmentation (B), irreversible collapse of the artificial vena cava occurs in reproducible fashion at a given pump speed of 2300 ± 50 RPM and a pump inlet pressure of -112 mmHg. Furthermore, bubbles form at the cannula tip despite the fact that the entire system is immersed in water and air from the environment cannot enter the system. This phenomenon is also known as cavitation and should be avoided because of local damage of both formed blood elements and endothelium, as well embolization. CONCLUSIONS: This caval model provides a realistic picture for the limitations of flow due to spontaneously reversible atrial chatter vs irreversible venous collapse for a given negative pressure during CPB. Temporary interruption of negative pressure in the venous line can allow for recovery of venous drainage. This know-how can be used not only for testing different cannula designs, but also for further optimizing perfusion strategies.

Avaliação de Impacte de Apanha e Extracção de Inertes na Ribeira da Barca – Ilha de Santiago – Cabo Verde

O estudo realizou um diagnóstico ambiental na Ribeira da Barca, Concelho de Santa Catarina, Ilha de Santiago, no sentido de se identificar, avaliar, e caracterizar as alterações na paisagem, causadas pelas actividades extractivas nas crateras da Ribeira da Barca, estimar a quantidade de inertes extraídas ao longo do tempo. O trabalho de levantamento de campo foi realizado entre Novembro de 2010 e Maio de 2011. A paisagem estudada enquadra-se bem num processo de transformação por acções antropogénicas negativas, relativamente à extracção ao comércio de areia e brita. O leito da ribeira apresenta-se totalmente esburacado, com cavas de dimensões que variam desde de 2,6 m até 46,90 m de comprimento, largura de 2,90m até 28,10 m; altura/profundidade de 0,12 m até 2,70 m , provocando uma distorção no carácter visual de todo o leito. Das vinte e três (23) cavas monitorizadas durante seis meses de estudo 26,1% das cavas (cerca de 6), tiveram uma evolução considerável, em termos de comprimento, largura e altura/profundidade; 34,8% (cerca de 8) tiveram uma evolução menos considerável; 39,1% das cavas (cerca de 9 ) não evoluíram. Torna-se necessária adequar uma estratégia que possa agir de forma "positiva" baseada num processo de recuperação da paisagem.

Selling to consumers with endogenous types

For many goods (such as experience goods or addictive goods), consumers preferences may change over time. In this paper, we examine a monopolist s optimal pricing schedule when current consumption can affect a consumer s valuation in the future and valuations are unobservable. We assume that consumers are anonymous, i.e. the monopolist can t observe a consumer s past consumption history. For myopic consumers, the optimal consumption schedule is distorted upwards, involving substantial discounts for low valuation types. This pushes low types into higher valuations, from which rents can be extracted.For forward looking consumers, there may be a further upward distortion of consumption due to a reversal of the adverse selection effect; low valuation consumers now have a strong interest in consumption in order to increase their valuations. Firms will find it profitable to educate consumers and encourage forward looking behavior.

Implementação do abc (activity-based costing) numa empresa prestação de serviços de saúde

O presente trabalho cujo título é Implementação do ABC numa empresa prestadora de serviços de Saúde, tem como finalidade a obtenção do grau de licenciatura em Contabilidade e Administração e tem como principal objectivo a implementação do método ABC numa pequena e média empresa de prestação de serviços de saúde, como um instrumento de apoio á gestão. Para a introdução da Contabilidade de Gestão na empresa, há que se escolher um método/sistema de apuramento de gastos que espelha a realidade da empresa, e de uma certa forma o ABC é o método ideal para apuramento de resultados sem distorções. O ABC (Activity-Based Cost) apura os resultados através da relação de causa-efeito, considerando que as actividades é que geram gastos e os objectos de custeio é que consomem as actividades. É aplicável tanto nas empresas industriais como nas empresas prestadoras de serviços, apesar de inicialmente ter sido concebido para as empresas industrias, isto é, para as grandes empresas devido aos avultados recursos financeiros e humanos como também pelo tempo necessário para a sua implementação. Mas o modelo matricial apresentado por Roztcki et al (1999) permite a aplicação deste método nas PME com poucos recursos financeiros e de tempo, utilizando uma folha de cálculo no Excel. Será este modelo a ser proposto e poderá ser implementado na clínica. O modelo apresentado foi testado num estudo de caso realizado numa clínica. Com a realização dos testes foi detectado algumas dificuldades e limitações, as maiores dificuldades encontradas foram a identificação das actividades e dos cost drivers, devido à complexidade do sector. A implementação foi concluída com sucesso, proporcionando informações detalhadas dos gastos dos produtos/serviços prestados em toda a clínica. This work was done as a requisite for obtaining a degree in Accounting and Administration, and is titled “The Implementation of ABC – Activity Based Cost in a company that provides health services”. Its main purpose is to analyze the implementation of ABC method in a small and medium-sized enterprise which provides health services to support decision making by the Managers. To adopt management accounting in a company, it’s necessary to choose a cost qualifying system that reflects the reality of the company and in a certain way ABC is the method which can determine the results without any distortion. ABC (Activity-Based Cost) determines the results through cause-and-effect relationship, whereas the activities generate spending while costing objects consume the activities. It’s applicable both in industrial companies as in services providers, although it was initially designed for industrial companies, that is, to large companies, due to the huge financial and human resources existent as well as by the time required for its implementation. But the matrix model presented by Roztckiet al (1999) allows application of this method in small and medium-sized enterprises with limited financial resources and time, using a spreadsheet in Excel. This model will be proposed and could be implemented in any clinic. The model was tested in a case study, undertaken in a private clinic. With the realization of the tests, some problems and limitations were detected, and the major difficulties encountered were the identification of activities and cost drivers, due to the complexity of the sector. The implementation was completed successfully, providing detailed information of the products services spending throughout the clinic.

The gain-loss asymmetry and single-self preferences

Kahneman and Tversky asserted a fundamental asymmetry between gains and losses, namely a reflection effect which occurs when an individual prefers a sure gain of $ pz to anuncertain gain of $ z with probability p, while preferring an uncertain loss of $z with probability p to a certain loss of $ pz.We focus on this class of choices (actuarially fair), and explore the extent to which thereflection effect, understood as occurring at a range of wealth levels, is compatible with single-self preferences.We decompose the reflection effect into two components, a probability switch effect,which is compatible with single-self preferences, and a translation effect, which is not. To argue the first point, we analyze two classes of single-self, nonexpected utility preferences, which we label homothetic and weakly homothetic. In both cases, we characterize the switch effect as well as the dependence of risk attitudes on wealth.We also discuss two types of utility functions of a form reminiscent of expected utility but with distorted probabilities. Type I always distorts the probability of the worst outcome downwards, yielding attraction to small risks for all probabilities. Type II distorts low probabilities upwards, and high probabilities downwards, implying risk aversion when the probability of the worst outcome is low. By combining homothetic or weak homothetic preferences with Type I or Type II distortion functions, we present four explicit examples: All four display a switch effect and, hence, a form of reflection effect consistent a single self preferences.