TIROS-N Cosmic Ray study

An experimental and analytical study was performed on the impact of galactic cosmic rays on the TIROS-N satellite memory in orbit. Comparisons were made of systems equipped with the Harris HMI-6508 1 x 1024 CMOS/bulk RAM and the RCA CDP-1821 1 x 1024 bit CMOS/SOS RAM. Based upon the experimental results, estimated bit error rates were determined. These were at least 8.0 bit errors/day for a 300 kilobit memory with the HMI-6508 and .014 bit errors/day with the CDF-1821. It was also estimated that the HMI-6508 latchup rate in orbit is at least two orders of magnitude less than the bit error rates; the CDP-1821 will not latchup

Organic Cation Transporter 3 (OCT3) Is Localized to Intracellular and Surface Membranes in Select Glial and Neuronal Cells Within the Basolateral Amygdaloid Complex of Both Rats and Mice

Organic cation transporter 3 (OCT3) is a high-capacity, low-affinity transporter that mediates corticosterone-sensitive uptake of monoamines including norepinephrine, epinephrine, dopamine, histamine and serotonin. OCT3 is expressed widely throughout the amygdaloid complex and other brain regions where monoamines are key regulators of emotional behaviors affected by stress. However, assessing the contribution of OCT3 to the regulation of monoaminergic neurotransmission and monoamine-dependent regulation of behavior requires fundamental information about the subcellular distribution of OCT3 expression. We used immunofluorescence and immuno-electron microscopy to examine the cellular and subcellular distribution of the transporter in the basolateral amygdaloid complex of the rat and mouse brain. OCT3-immunoreactivity was observed in both glial and neuronal perikarya in both rat and mouse amygdala. Electron microscopic immunolabeling revealed plasma membrane-associated OCT3 immunoreactivity on axonal, dendritic, and astrocytic processes adjacent to a variety of synapses, as well as on neuronal somata. In addition to plasma membrane sites, OCT3 immunolabeling was also observed associated with neuronal and glial endomembranes, including Golgi, mitochondrial and nuclear membranes. Particularly prominent labeling of the outer nuclear membrane was observed in neuronal, astrocytic, microglial and endothelial perikarya. The localization of OCT3 to neuronal and glial plasma membranes adjacent to synaptic sites is consistent with an important role for this transporter in regulating the amplitude, duration, and physical spread of released monoamines, while its localization to mitochondrial and outer nuclear membranes suggests previously undescribed roles for the transporter in the intracellular disposition of monoamines

Hypopituitarism and brain injury: recent advances in screening and management

This review gives an overview of the research on hypothalamopituitary dysfunction as a potential consequence of traumatic brain injury, including the natural history of this complication and its clinical and public health implications

Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection

Multiplicity is one of the most fundamental observable properties of massive O-type stars and offers a promising way to discriminate between massive star formation theories. Nevertheless, companions at separations between 1 and 100 mas remain mostly unknown due to intrinsic observational limitations. [...] The Southern MAssive Stars at High angular resolution survey (SMASH+) was designed to fill this gap by providing the first systematic interferometric survey of Galactic massive stars. We observed 117 O-type stars with VLTI/PIONIER and 162 O-type stars with NACO/SAM, respectively probing the separation ranges 1-45 and 30-250mas and brightness contrasts of Delta H < 4 and Delta H < 5. Taking advantage of NACO's field-of-view, we further uniformly searched for visual companions in an 8''-radius down to Delta H = 8. This paper describes the observations and data analysis, reports the discovery of almost 200 new companions in the separation range from 1mas to 8'' and presents the catalog of detections, including the first resolved measurements of over a dozen known long-period spectroscopic binaries. Excluding known runaway stars for which no companions are detected, 96 objects in our main sample (DEC < 0 deg; H<7.5) were observed both with PIONIER and NACO/SAM. The fraction of these stars with at least one resolved companion within 200mas is 0.53. Accounting for known but unresolved spectroscopic or eclipsing companions, the multiplicity fraction at separation < 8'' increases to f_m = 0.91 +/- 0.03. The fraction of luminosity class V stars that have a bound companion reaches 100% at 30mas while their average number of physically connected companions within 8'' is f_c = 2.2 +/- 0.3. This demonstrates that massive stars form nearly exclusively in multiple systems. Additionally, the nine non-thermal (NT) radio emitters observed by SMASH+ are all resolved [...]Comment: 57 pages, 20 figures, 7 tables; accepted for publication in ApJ

Medial prefrontal cortex neuronal activation and synaptic alterations after stress-induced reinstatement of palatable food seeking: a study using c-fos-GFP transgenic female rats

Relapse to maladaptive eating habits during dieting is often provoked by stress and there is evidence for a role of ovarian hormones in stress responses and feeding. We studied the role of these hormones in stress-induced reinstatement of food seeking and medial prefrontal cortex (mPFC) neuronal activation in c-fos-GFP transgenic female rats, which express GFP in strongly activated neurons. Food-restricted ovariectomized or sham-operated c-fos-GFP rats were trained to lever-press for palatable food pellets. Subsequently, lever-pressing was extinguished and reinstatement of food seeking and mPFC neuronal activation was assessed after injections of the pharmacological stressor yohimbine (0.5-2 mg/kg) or pellet priming (1-4 noncontingent pellets). Estrous cycle effects on reinstatement were also assessed in wild-type rats. Yohimbine- and pellet-priming-induced reinstatement was associated with Fos and GFP induction in mPFC; both reinstatement and neuronal activation were minimally affected by ovarian hormones in both c-fos-GFP and wild-type rats. c-fos-GFP transgenic rats were then used to assess glutamatergic synaptic alterations within activated GFP-positive and nonactivated GFP-negative mPFC neurons following yohimbine-induced reinstatement of food seeking. This reinstatement was associated with reduced AMPA receptor/NMDA receptor current ratios and increased paired-pulse facilitation in activated GFP-positive but not GFP-negative neurons. While ovarian hormones do not appear to play a role in stress-induced relapse of food seeking in our rat model, this reinstatement was associated with unique synaptic alterations in strongly activated mPFC neurons. Our paper introduces the c-fos-GFP transgenic rat as a new tool to study unique synaptic changes in activated neurons during behavio

Nonlinear Proportional Plus Integral Control of Optical Traps for Exogenous Force Estimation

This article explores nonlinear proportional plus integral (PI) feedback for controlling the position of an object held in an optical trap. In general, nonlinearities in the spatial dependence of the optical force complicate feedback control for optical traps. Nonlinear PI control has been shown to provide all of the benefits of integral control: disturbance rejection, servo tracking, and force estimation. The controller also linearizes the closed-loop system. More importantly, the nonlinear controller is shown to be equivalent to an estimator of the exogenous force. The ability of nonlinear PI control to lower the measurement SNR is evaluated and compared to the variational open-loop case. A simulation demonstrating the performance of the nonlinear PI control is presented

Gamma motor neurons express distinct genetic markers at birth and require muscle spindle-derived GDNF for postnatal survival

<p>Abstract</p> <p>Background</p> <p>Gamma motor neurons (γ-MNs) selectively innervate muscle spindle intrafusal fibers and regulate their sensitivity to stretch. They constitute a distinct subpopulation that differs in morphology, physiology and connectivity from α-MNs, which innervate extrafusal muscle fibers and exert force. The mechanisms that control the differentiation of functionally distinct fusimotor neurons are unknown. Progress on this question has been limited by the absence of molecular markers to specifically distinguish and manipulate γ-MNs. Recently, it was reported that early embryonic γ-MN precursors are dependent on GDNF. Using this knowledge we characterized genetic strategies to label developing γ-MNs based on GDNF receptor expression, showed their strict dependence for survival on muscle spindle-derived GDNF and generated an animal model in which γ-MNs are selectively lost.</p> <p>Results</p> <p>In mice heterozygous for both the <it>Hb9::GFP </it>transgene and a tau-lacZ-labeled (<it>TLZ</it>) allele of the GDNF receptor Gfrα1, we demonstrated that small motor neurons with high Gfrα1-TLZ expression and lacking Hb9::GFP display structural and synaptic features of γ-MNs and are selectively lost in mutants lacking target muscle spindles. Loss of muscle spindles also results in the downregulation of Gfrα1 expression in some large diameter MNs, suggesting that spindle-derived factors may also influence populations of α-MNs with β-skeletofusimotor collaterals. These molecular markers can be used to identify γ-MNs from birth to the adult and to distinguish γ- from β-motor axons in the periphery. We also found that postnatal γ-MNs are also distinguished by low expression of the neuronal nuclear protein (NeuN). With these markers of γ-MN identity, we show after conditional elimination of GDNF from muscle spindles that the survival of γ-MNs is selectively dependent on spindle-derived GDNF during the first 2 weeks of postnatal development.</p> <p>Conclusion</p> <p>Neonatal γ-MNs display a unique molecular profile characterized by the differential expression of a series of markers - Gfrα1, Hb9::GFP and NeuN - and the selective dependence on muscle spindle-derived GDNF. Deletion of GDNF expression from muscle spindles results in the selective elimination of γ-MNs with preservation of the spindle and its sensory innervation. This provides a mouse model with which to explore the specific role of γ-fusimotor activity in motor behaviors.</p

Lieux remplis, lieux vidés : temporalités touristiques

Le projet de ce chapitre est de proposer une méthode d\u27observation des variations temporelles d\u27occupation des lieux. L\u27hypothèse est que les changements quantitatifs de la fréquentation et/ou de ses rythmes peuvent exprimer aussi des changements qualitatifs de leurs usages, un changement d’habiter, donc, plus particulièrement liées au tourisme. Notre étude s\u27est portée sur deux lieux urbains ayant des fonctionnalités touristiques : Châtelaillon et Les Minimes en Charente-Maritime

Frege on the Tolerability of Sense Variation: A Reply to Michaelson and Textor

In several passages, Frege suggests that successful communication requires that speaker and audience understand the uttered words and sentences to have the same sense. On the other hand, Frege concedes that, in many ordinary cases, variation in sense is tolerable. In a recent article in this journal, Michaelson and Textor (2023) offer a new interpretation of Frege on the tolerability of sense variation according to which variation in sense is tolerable when the conversation aims at joint action, but not when the conversation aims at joint thought. We maintain, contra Michaelson and Textor, that whether sense variation is tolerable does not depend on the conversational purpose, whether it be theoretical or practical. Rather, whether sense variation is tolerable depends instead on the conversational background. This picture offers what we take to be a more plausible reconstruction of Frege’s own view

All the Brain\u27s a Stage for Serotonin: The Forgotten Story of Serotonin Diffusion across Cell Membranes

In the conventional model of serotonin neurotransmission, serotonin released by neurons in the midbrain raphe nuclei exerts its actions on forebrain neurons by interacting with a large family of post-synaptic receptors. The actions of serotonin are terminated by active transport of serotonin back into the releasing neuron, which is mediated by the serotonin reuptake transporter (SERT). Because SERT is expressed pre-synaptically and is widely thought to be the only serotonin transporter in the forebrain, the conventional model does not include serotonin transport into post-synaptic neurons. However, a large body of evidence accumulating since the 1970s has shown that serotonin, despite having a positive charge, can cross cell membranes through a diffusion-like process. Multiple low-affinity, high-capacity, sodium-independent transporters, widely expressed in the brain, allow the carrier-mediated diffusion of serotonin into forebrain neurons. The amount of serotonin crossing cell membranes through this mechanism under physiological conditions is considerable. Most prominent textbooks fail to include this alternative method of serotonin uptake in the brain, and even most neuroscientists are unaware of it. This failure has limited our understanding of a key regulator of serotonergic neurotransmission, impeded research on the potential intracellular actions of serotonin in post-synaptic neurons and glial cells, and may have impeded our understanding of the mechanism by which antidepressant medications reduce depressive symptoms