The use of location and location-intensity patterns in electrocutaneous communication Annual report, 1 May 1965 - 30 Apr. 1966

Language communication by electrical stimulation of ski

Electronic structure of spinel-type LiV_2O_4

The band structure of the cubic spinel compound LiV_2O_4, which has been reported recently to show heavy Fermion behavior, has been calculated within the local-density approximation using a full-potential version of the linear augmented-plane-wave method. The results show that partially-filled V 3d bands are located about 1.9 eV above the O 2p bands and the V 3d bands are split into a lower partially-filled t_{2g} complex and an upper unoccupied e_{g} manifold. The fact that the conduction electrons originate solely from the t_{2g} bands suggests that the mechanism for the mass enhancement in this system is different from that in the 4f heavy Fermion systems, where these effects are attributed to the hybridization between the localized 4f levels and itinerant spd bands.Comment: 5 pages, revte

Spin currents and spin dynamics in time-dependent density-functional theory

We derive and analyse the equation of motion for the spin degrees of freedom within time-dependent spin-density-functional theory (TD-SDFT). Results are (i) a prescription for obtaining many-body corrections to the single-particle spin currents from the Kohn-Sham equation of TD-SDFT, (ii) the existence of an exchange-correlation (xc) torque within TD-SDFT, (iii) a prescription for calculating, from TD-SDFT, the torque exerted by spin currents on the spin magnetization, (iv) a novel exact constraint on approximate xc functionals, and (v) the discovery of serious deficiencies of popular approximations to TD-SDFT when applied to spin dynamics.Comment: now includes discussion of OEP and GGA; to appear in Phys. Rev. Let

De Novo Missense Variants in SLC32A1 Cause a Developmental and Epileptic Encephalopathy Due to Impaired GABAergic Neurotransmission

Objective:Rare inherited missense variants inSLC32A1, the gene that encodes the vesicular gamma-aminobutyric acid(GABA) transporter, have recently been shown to cause genetic epilepsy with febrile seizures plus. We aimed to clarifyif de novo missense variants inSLC32A1can also cause epilepsy with impaired neurodevelopment.Methods:Using exome sequencing, we identified four individuals with a developmental and epileptic encephalopathyand de novo missense variants inSLC32A1. To assess causality, we performed functional evaluation of the identifiedvariants in a murine neuronal cell culture model.Results:The main phenotype comprises moderate-to-severe intellectual disability, infantile-onset epilepsy within thefirst 18 months of life, and a choreiform, dystonic, or dyskinetic movement disorder. In silico modeling and functionalanalyses reveal that three of these variants, which are located in helices that line the putative GABA transport pathway,result in reduced quantal size, consistent with impairedfilling of synaptic vesicles with GABA. The fourth variant,located in the vesicular gamma-aminobutyric acid N-terminus, does not affect quantal size, but increases presynapticrelease probability, leading to more severe synaptic depression during high-frequency stimulation. Thus, variants invesicular gamma-aminobutyric acid can impair GABAergic neurotransmission through at least two mechanisms, byaffecting synaptic vesiclefilling and by altering synaptic short-term plasticity.Interpretation:This work establishes de novo missense variants inSLC32A1as a novel cause of a developmental andepileptic encephalopathy

Electron correlation effects and magnetic ordering at the Gd(0001) surface

Effects of electron correlation on the electronic structure and magnetic properties of the Gd(0001) surface are investigated using of the full-potential linearized augmented plane wave implementation of correlated band theory ("LDA+U"). The use of LDA+U instead of LDA (local density approximation) total energy calculations produces the correct ferromagnetic ground state for both bulk Gd and the Gd surface. Surface strain relaxation leads to an 90 % enhancement of the interlayer surface-to-bulk effective exchange coupling. Application of a Landau-Ginzburg type theory yields a 30 % enhancement of the Curie temperature at the surface, in very good agreement with the experiment.Comment: revised version: minor typos correcte

Repeated exposure to transient obstructive sleep apnea-related conditions causes an atrial fibrillation substrate in a chronic rat model

Background High night-to-night variability in obstructive sleep apnea (OSA) is associated with atrial fibrillation (AF). Obstructive apneas are characterized by intermittent deoxygenation-reoxygenation and intrathoracic pressure swings during ineffective inspiration against occluded upper airways. Objective We elucidated the effect of repeated exposure to transient OSA conditions simulated by intermittent negative upper airway pressure (INAP) on the development of an AF substrate. Methods INAP (48 events/4 h; apnea-hypopnea index 12 events/h) was applied in sedated spontaneously breathing rats (2% isoflurane) to simulate mild-to-moderate OSA. Rats without INAP served as a control group (CTR). In an acute test series (ATS), rats were either killed immediately (n = 9 per group) or after 24 hours of recovery (ATS-REC: n = 5 per group). To simulate high night-to-night variability in OSA, INAP applications (n = 10; 24 events/4 h; apnea-hypopnea index 6/h) were repeated every second day for 3 weeks in a chronic test series (CTS). Results INAP increased atrial oxidative stress acutely, represented in decreases of reduced to oxidized glutathione ratio (ATS: INAP: 0.33 ± 0.05 vs CTR: 1 ± 0.26; P = .016), which was reversible after 24 hours (ATS-REC: INAP vs CTR; P = .274). Although atrial oxidative stress did not accumulate in the CTS, atrial histological analysis revealed increased cardiomyocyte diameters, reduced connexin 43 expression, and increased interstitial fibrosis formation (CTS: INAP 7.0% ± 0.5% vs CTR 5.1% ± 0.3%; P = .013), which were associated with longer inducible AF episodes (CTS: INAP: 11.65 ± 4.43 seconds vs CTR: 0.7 ± 0.33 seconds; P = .033). Conclusion Acute simulation of OSA was associated with reversible atrial oxidative stress. Cumulative exposure to these transient OSA-related conditions resulted in AF substrates and was associated with increased AF susceptibility. Mild-to-moderate OSA with high night-to-night variability may deserve intensive management to prevent atrial substrate development

Intersubband spin-density excitations in quantum wells with Rashba spin splitting

In inversion-asymmetric semiconductors, spin-orbit coupling induces a k-dependent spin splitting of valence and conduction bands, which is a well-known cause for spin decoherence in bulk and heterostructures. Manipulating nonequilibrium spin coherence in device applications thus requires understanding how valence and conduction band spin splitting affects carrier spin dynamics. This paper studies the relevance of this decoherence mechanism for collective intersubband spin-density excitations (SDEs) in quantum wells. A density-functional formalism for the linear spin-density matrix response is presented that describes SDEs in the conduction band of quantum wells with subbands that may be non-parabolic and spin-split due to bulk or structural inversion asymmetry (Rashba effect). As an example, we consider a 40 nm GaAs/AlGaAs quantum well, including Rashba spin splitting of the conduction subbands. We find a coupling and wavevector-dependent splitting of the longitudinal and transverse SDEs. However, decoherence of the SDEs is not determined by subband spin splitting, due to collective effects arising from dynamical exchange and correlation.Comment: 10 pages, 4 figure

Facilitating Student Learning Through Contextualization

This Brief, based on a longer review that considers the hypothesis that low-skilled students can learn more effectively and advance to college-level programs more readily through contextualization of basic skills instruction, presents two forms of contextualization that have been studied: “contextualized“ and “integrated“ instruction. There is more descriptive work on the contextualization of basic skills than studies with student outcome data. In addition, many studies with quantitative evidence on the effectiveness of contextualization have methodological flaws that limit conclusions. Further, only a small number of studies are with college students. However, despite these problems, contextualization seems to be a promising direction for accelerating the progress of academically underprepared college students. The method of contextualization is grounded in a conceptual framework relating to the transfer of skill and student motivation; practitioners who use it observe positive results, and the available quantitative evidence indicates that it has the potential to increase achievement

Profiling of WDR36 Missense Variants in German Patients with Glaucoma

PURPOSE. Mutations in WDR36 were recently reported in patients with adult-onset primary open-angle glaucoma (POAG). In this study, the prevalence of WDR36 variants was investigated in patients with glaucoma who were of German descent with diverse age of onset and intraocular pressure levels. METHODS. Recruited were 399 unrelated patients with glaucoma and 376 healthy subjects of comparable age and origin, who had had repeated normal findings in ophthalmic examinations. The frequency of observed variants was obtained by direct sequencing of the entire WDR36 coding region. RESULTS. A total of 44 WDR36 allelic variants were detected, including 14 nonsynonymous amino acid alterations, of which 7 are novel (P31T, Y97C, D126N, T403A, H411Y, H411L, and P487R) and 7 have been reported (L25P, D33E, A163V, H212P, A449T, D658G and I264V). Of these 14 variants, 6 were classified as polymorphisms as they were detected in patients and control individuals at similar frequencies. Eight variants present in 15 patients (3.7%) but only 1 control individual (0.2%) were defined as putative disease-causing variants (P 0.0005). Within this patient group, 12 (80%) presented with high and 3 (20%) with low intraocular pressure. Disease severity and age of onset showed a broad range. CONCLUSIONS. The occurrence of several rare putative diseasecausing variants in patients with glaucoma suggests that WDR36 may be a minor disease-causing gene in glaucoma, at least in the German population. The large variability in WDR36, though, requires functional validation of these variants, once its function is characterized.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí