582 research outputs found
Adaptive sliding-mode observer for second order discrete-time MIMO nonlinear systems based on recurrent neural-networks
Beyond traditional understanding of gender measurement: the gender (re)presentation approach
This paper considers different approaches to measuring gender. It critically reviews gender role theorising and describes how this has informed two approaches to measuring gender as an individual phenomenon: gender orientation (the assessment of individual traits) and gender ideology (assessing individual endorsement, and
internalisation, of social norms). It is argued here that social constructionist perspectives offer a viable alternative to gender role theory and that these inform an alternative approach to measuring gender as a social phenomenon: gender (re)presentation. This approach assesses group level endorsement of dominant gender representations. Endorsement is not seen to reflect individual traits or internalised social norms. Rather, it is understood as a social practice, made meaningful through shared understanding of dominant gender representation. This approach is introduced through a critique of the traditional concept of attitudes and a reformulation thereof. The practical measurement implications and benefit of this reformulation are outlined
A Note on the Regularity of Inviscid Shell Model of Turbulence
In this paper we continue the analytical study of the sabra shell model of
energy turbulent cascade initiated in \cite{CLT05}. We prove the global
existence of weak solutions of the inviscid sabra shell model, and show that
these solutions are unique for some short interval of time. In addition, we
prove that the solutions conserve the energy, provided that the components of
the solution satisfy , for
some positive absolute constant , which is the analogue of the Onsager's
conjecture for the Euler's equations. Moreover, we give a Beal-Kato-Majda type
criterion for the blow-up of solutions of the inviscid sabra shell model and
show the global regularity of the solutions in the ``two-dimensional''
parameters regime
Dopamine receptor alterations in female rats with diet-induced decreased brain docosahexaenoic acid (DHA): interactions with reproductive status
Decreased tissue levels of n-3 (omega-3) fatty acids, particularly docosahexaenoic acid (DHA), are implicated in the etiologies of non-puerperal and postpartum depression. This study examined the effects of a diet-induced loss of brain DHA content and concurrent reproductive status on dopaminergic parameters in adult female Long–Evans rats. An α-linolenic acid-deficient diet and breeding protocols were used to produce virgin and parous female rats with cortical phospholipid DHA levels 20–22% lower than those fed a control diet containing adequate α-linolenic acid. Decreased brain DHA produced a significant main effect of decreased density of ventral striatal D2-like receptors. Virgin females with decreased DHA also exhibited higher density of D1-like receptors in the caudate nucleus than virgin females with normal DHA. These receptor alterations are similar to those found in several rodent models of depression, and are consistent with the proposed hypodopaminergic basis for anhedonia and motivational deficits in depression
Dopamine D2 receptor function is compromised in the brain of the methionine sulfoxide reductase A knockout mouse
Previous research suggests that brain oxidative stress and altered rodent locomotor behavior are linked. We observed bio-behavioral changes in methionine sulfoxide reductase A knockout mice associated with abnormal dopamine signaling. Compromised ability of these knockout mice to reduce methionine sulfoxide enhances accumulation of sulfoxides in proteins. We examined the dopamine D2-receptor function and expression, which has an atypical arrangement and quantity of methionine residues. Indeed, protein expression levels of dopamine D2-receptor were higher in knockout mice compared with wild-type. However, the binding of dopamine D2-receptor agonist was compromised in the same fractions of knockout mice. Coupling efficiency of dopamine D2-receptors to G-proteins was also significantly reduced in knockout mice, supporting the compromised agonist binding. Furthermore, pre-synaptic dopamine release in knockout striatal sections was less responsive than control sections to dopamine D2-receptor ligands. Behaviorally, the locomotor activity of knockout mice was less responsive to the inhibitory effect of quinpirole than wild-type mice. Involvement of specific methionine residue oxidation in the dopamine D2-receptor third intracellular loop is suggested by in vitro studies. We conclude that ablation of methionine sulfoxide reductase can affect dopamine signaling through altering dopamine D2-receptor physiology and may be related to symptoms associated with neurological disorders and diseases
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Alexithymia in Men: How and When Do Emotional Processing Deficiencies Occur?
The present study extended existing research on alexithymia in men, investigating whether the deficit in processing emotions occurs early in the process, as a result of dissociation or repression, or later, as a result of suppression. We also examined the assumption in Levant’s (2011) normative male alexithymia hypothesis that men with alexithymia would show the greatest deficits in identifying words for emotions discouraged by masculine norms that expressed vulnerability and attachment. Study 1, with 258 college men, showed that scores on measures of alexithymia and normative male alexithymia were more strongly and uniquely predicted by suppression than repression and dissociation, while controlling for positive and negative affect and depression. Study 2 used semantic priming with 85 college men, and revealed that men with alexithymia showed more errors in lexical decision performance using target emotion words discouraged by masculine norms as compared to men without alexithymia. In addition, men with and without alexithymia did not differ in their accuracy using target emotion words that are encouraged by masculine norms. We also found that the disruption in emotional processing among men with alexithymia occurred at 500 ms stimulus onset asynchrony, which is slow enough for conscious processing, supporting an explanation of suppression as the mechanism for the inhibition.Keywords: Repression, Inhibition, Suppression, Semantic Priming, Normative Male Alexithymi
Reaction rate reconstruction from biomass concentration measurement in bioreactors using modified second-order sliding mode algorithms
This paper deals with the estimation of unknown
signals in bioreactors using sliding observers. Particular
attention is drawn to estimate the specific growth rate of
microorganisms from measurement of biomass concentration.
In a recent article, notions of high-order sliding modes have
been used to derive a growth rate observer for batch processes.
In this paper we generalize and refine these preliminary results.
We develop a new observer with a different error structure to
cope with other types of processes. Furthermore, we show that
these observers are equivalent, under coordinate transformations
and time scaling, to the classical super-twisting differentiator
algorithm, thus inheriting all its distinctive features.
The new observers’ family achieves convergence to timevarying
unknown signals in finite time, and presents the best
attainable estimation error order in the presence of noise. In
addition, the observers are robust to modeling and parameter
uncertainties since they are based on minimal assumptions
on bioprocess dynamics. In addition, they have interesting
applications in fault detection and monitoring. The observers
performance in batch, fed-batch and continuous bioreactors is
assessed by experimental data obtained from the fermentation
of Saccharomyces Cerevisiae on glucose.This work was supported by the National University of La Plata (Project 2012-2015), the Agency for the Promotion of Science and Technology ANPCyT (PICT2007-00535) and the National Research Council CONICET (PIP112-200801-01052) of Argentina; the Technical University of Valencia (PAID-02-09), the CICYT (DPI2005-01180) and AECID (A/024186/09) of Spain; and by the project FEDER of the European Union.De Battista, H.; Picó Marco, JA.; Garelli, F.; Navarro Herrero, JL. (2012). Reaction rate reconstruction from biomass concentration measurement in bioreactors using modified second-order sliding mode algorithms. Bioprocess and Biosystems Engineering. 35(9):1-11. https://doi.org/10.1007/s00449-012-0752-yS111359Aborhey S, Williamson D (1978) State amd parameter estimation of microbial growth process. Automatica 14:493–498Bastin G, Dochain D (1986) On-line estimation of microbial specific growth rates. 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IEEE Transact Automatic Control 50(11):1785–1789De Battista H, Picó J, Garelli F, Vignoni A (2011) Specific growth rate estimation in (fed-)batch bioreactors using second-order sliding observers. J Process Control 21:1049–1055Dochain D (2001) Bioprocess control. Wiley, HobokenDochain D (2003) State and parameter estimation in chemical and biochemical processes: a tutorial. J Process Control 13(8):801–818Edwards C, Spurgeon S, Patton R (2000) Sliding mode observers for fault detection and isolation. Automatica 36(2):541–553Evangelista C, Puleston P, Valenciaga F, Fridman L (2012) Lyapunov designed super-twisting sliding mode control for wind energy conversion optimization. Indus Electron IEEE Transact. doi: 10.1109/TIE.2012.2188256Farza M, Busawon K, Hammouri H (1998) Simple nonlinear observers for on-line estimation of kinetic rates in bioreactors. Automatica 34(3):301–318Fridman L, Davila J, Levant A (2008) High-order sliding modes observation. In: International workshop on variable structure systems, pp 203–208Fridman L, Levant A (2002) Sliding mode control in engineering, higher-order sliding modes. Marcel Dekker, Inc., New York, pp 53–101Fridman L, Shtessel Y, Edwards C, Yan X (2008) Higher-order sliding-mode observer for state estimation and input reconstruction in nonlinear systems. Int J Robust Nonlinear Control 18(3–4):399–412Gauthier J, Hammouri H, Othman S (1992) A simple observer for nonlinear systems: applications to bioreactors. IEEE Transact Automatic Control 37(6):875–880Gnoth S, Jenzsch M, Simutis R, Lubbert A (2008) Control of cultivation processes for recombinant protein production: a review. Bioprocess Biosyst Eng 31(1):21–39Hitzmann B, Broxtermann O, Cha Y, Sobieh O, Stärk E, Scheper T (2000) The control of glucose concentration during yeast fed-batch cultivation using a fast measurement complemented by an extended kalman filter. Bioprocess Eng 23(4):337–341Kiviharju K, Salonen K, Moilanen U, Eerikainen T (2008) Biomass measurement online: the performance of in situ measurements and software sensors. J Indus Microbiol Biotechnol 35(7):657–665Levant A (1998) Robust exact differentiation via sliding mode technique. Automatica 34(3):379–384Levant A (2003) Higher-order sliding modes, differentiation and output-feedback control. Int J Control 76(9/10):924–941Lubenova V, Rocha I, Ferreira E (2003) Estimation of multiple biomass growth rates and biomass concentration in a class of bioprocesses. Bioprocess Biosyst Eng 25:395–406Moreno J, Alvarez J, Rocha-Cozatl E, Diaz-Salgado J (2010) Super-twisting observer-based output feedback control of a class of continuous exothermic chemical reactors. In: Proceedings of the 9th IFAC international symposium on dynamics and control of process systems, pp 719–724. Leuven, BelgiumMoreno J, Osorio M (2008) A Lyapunov approach to second-order sliding mode controllers and observers. In: Proceedings of the 47th IEEE conference on decision and control. Cancún, México, pp 2856–2861Moreno J, Osorio M (2012) Strict Lyapunov functions for the super-twisting algorithm. IEEE Transact Automatic Control 57:1035–1040Navarro J, Picó J, Bruno J, Picó-Marco E, Vallés S (2001) On-line method and equipment for detecting, determining the evolution and quantifying a microbial biomass and other substances that absorb light along the spectrum during the development of biotechnological processes. Patent ES20010001757, EP20020751179Neeleman Boxtel (2001) Estimation of specific growth rate from cell density measurements. Bioprocess Biosyst Eng 24(3):179–185November E, van Impe J (2002) The tuning of a model-based estimator for the specific growth rate of Candidautilis. Bioprocess Biosyst Eng 25:1–12Park Y, Stein J (1988) Closed-loop, state and input observer for systems with unknown inputs. Int J Control 48(3):1121–1136Perrier M, de Azevedo SF, Ferreira E, Dochain D (2000) Tuning of observer-based estimators: theory and application to the on-line estimation of kinetic parameters. Control Eng Pract 8:377–388Picó J, De Battista H, Garelli F (2009) Smooth sliding-mode observers for specific growth rate and substrate from biomass measurement. J Process Control 19(8):1314–1323. Special section on hybrid systems: modeling, simulation and optimizationSchenk J, Balaszs K, Jungo C, Urfer J, Wegmann C, Zocchi A, Marison I, von Stockar U (2008) Influence of specific growth rate on specific productivity and glycosylation of a recombinant avidin produced by a Pichia pastoris Mut + strain. Biotecnol Bioeng 99(2):368–377Shtessel Y, Taleb M, Plestan F (2012) A novel adaptive-gain supertwisting sliding mode controller: Methodol Appl Automatica (in press)Soons Z, van Straten G, van der Pol L, van Boxtel A (2008) On line automatic tuning and control for fed-batch cultivation. 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Global and regional brain metabolic scaling and its functional consequences
Background: Information processing in the brain requires large amounts of
metabolic energy, the spatial distribution of which is highly heterogeneous
reflecting complex activity patterns in the mammalian brain.
Results: Here, it is found based on empirical data that, despite this
heterogeneity, the volume-specific cerebral glucose metabolic rate of many
different brain structures scales with brain volume with almost the same
exponent around -0.15. The exception is white matter, the metabolism of which
seems to scale with a standard specific exponent -1/4. The scaling exponents
for the total oxygen and glucose consumptions in the brain in relation to its
volume are identical and equal to , which is significantly larger
than the exponents 3/4 and 2/3 suggested for whole body basal metabolism on
body mass.
Conclusions: These findings show explicitly that in mammals (i)
volume-specific scaling exponents of the cerebral energy expenditure in
different brain parts are approximately constant (except brain stem
structures), and (ii) the total cerebral metabolic exponent against brain
volume is greater than the much-cited Kleiber's 3/4 exponent. The
neurophysiological factors that might account for the regional uniformity of
the exponents and for the excessive scaling of the total brain metabolism are
discussed, along with the relationship between brain metabolic scaling and
computation.Comment: Brain metabolism scales with its mass well above 3/4 exponen
Military deployment, masculinity and trauma : reviewing the connections
This article reviews the literature on deployment trauma and examines the limitations
of conventional understandings of trauma as they relate to veterans’ experiences.
It suggests that the failure to take into account social influences and social
relationships limits the usefulness of conventional approaches to trauma. The article
considers the role that masculinity plays in male veterans’ experience of and
sense making about trauma. It is suggested that while formal recognition of posttraumatic
stress disorder in the DSM has provided a helpful language for veterans,
it is an incomplete response. A new model of masculinity that better enables the male
veteran to speak about trauma and to reconnect with others has implications for
counselling practice with veterans
A framework for mixing methods in quantitative measurement development, validation, and revision: A case study
A framework for quantitative measurement development, validation, and revision that incorporates both qualitative and quantitative methods is introduced. It extends and adapts Adcock and Collier’s work, and thus, facilitates understanding of quantitative measurement development, validation, and revision as an integrated and cyclical set of procedures best achieved through mixed methods research. It also offers a systematic guide concerning how these procedures may be undertaken through detailing key “stages,” “levels,” and practical “tasks.” A case study illustrates how qualitative and quantitative methods may be mixed through the use of the proposed framework in the cross-cultural content- and construct-related validation and subsequent revision of a quantitative measure.The contribution of this article to mixed methods research literature is briefly discussed
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