Training induced adaptations in characteristics of postural reflexes in elderly men.

Science.gov (United States)

Granacher, U; Gollhofer, A; Strass, D

2006-12-01

The aging neuromuscular system is affected by structural and functional changes which lead to a general slowing down of neuromuscular performance and an increased risk of falling. The impact of heavy resistance (HR) training in the elderly on maximum voluntary contraction (MVC) and rate of force development (RFD) has been investigated in the past. However, the influence of sensorimotor (SENSO) training and HR training on the ability to compensate for gait perturbations has not yet been investigated in the elderly. Therefore, the purpose of the study was to examine the impact of HR and SENSO training in elderly men on unexpected treadmill perturbations. Functional reflex activity was recorded by means of surface EMG in 40 male subjects (>60 years) before and after 13 weeks of HR and SENSO training and in another 20 male subjects (>60 years), which served as a CONTROL-group. SENSO training resulted in a decrease in onset latency, an enhanced reflex activity in the prime mover as well as a decrease in maximal angular velocity of the ankle joint complex during the perturbation impulses. No significant changes were observed in the HR- and in the CONTROL-group. The results clearly indicate that SENSO training has an impact on spinal motor control mechanisms in the elderly. Training induced improvements in perception and procession of afferent information could be a possible reason for the increase in reflex contraction. Due to these adaptive processes, SENSO training could be a well-suited method for fall preventive programs in elderly people.

Trigeminal cardiac reflex and cerebral blood flow regulation

Directory of Open Access Journals (Sweden)

Dominga Lapi

2016-10-01

Full Text Available The stimulation of some facial regions is known to trigger the trigemino-cardiac reflex: the main stimulus is represented by the contact of the face with water. This phenomenon called diving reflex induces a set of reactions in the cardiovascular and respiratory systems occurring in all mammals, especially marine (whales, seals. During the immersion of the face in the water, the main responses are aimed at reducing the oxygen consumption of the organism. Accordingly reduction in heart rate, peripheral vasoconstriction, blood pooling in certain organs, especially the heart and brain, and an increase in blood pressure have been reported. Moreover, the speed and intensity of the reflex is inversely proportional to the temperature of the water: more cold the water, more reactions as described are strong. In the case of deep diving an additional effect, such as blood deviation, has been reported: the blood is requested within the lungs, to compensate for the increase in the external pressure, preventing them from collapsing.The trigeminal-cardiac reflex is not just confined to the diving reflex; recently it has been shown that a brief proprioceptive stimulation (10 min by jaw extension in rats produces interesting effects both at systemic and cerebral level, reducing the arterial blood pressure and vasodilating the pial arterioles. The arteriolar dilation is associated with rhythmic diameter changes characterized by an increase in the endothelial activity. Fascinating the stimulation of trigeminal nerve is able to activated the nitric oxide release by vascular endothelial. Therefore the aim of this review was to highlight the effects due to trigeminal cardiac reflex induced by a simple mandibular extension, because produced opposite effects compared to those elicited by the diving reflex as it induces hypotension and modulation of cerebral arteriolar tone.

Indian red scorpion venom-induced augmentation of cardio-respiratory reflexes and pulmonary edema involve the release of histamine.

Science.gov (United States)

Dutta, Abhaya; Deshpande, Shripad B

2011-02-01

Pulmonary edema is a consistent feature of Mesobuthus tamulus (MBT) envenomation. Kinins, prostaglandins and other inflammatory mediators are implicated in it. Since, histamine also increases capillary permeability, this study was undertaken to evaluate whether MBT venom utilizes histamine to produce pulmonary edema and augmentation of cardio-respiratory reflexes evoked by phenylbiguanide (PBG). Blood pressure, respiratory excursions and ECG were recorded in urethane anaesthetized adult rats. Injection of PBG (10 μg/kg) produced apnoea, hypotension and bradycardia and the responses were augmented after exposure to venom (100 μg/kg). There was increased pulmonary water content in these animals. Pretreatment with pheniramine maleate (H₁ antagonist, 3 mg/kg) blocked both venom-induced augmentation of PBG response and pulmonary edema. In another series, compound 48/80 (mast cell depletor) was treated for 4 days then the PBG responses were elicited as before. At the end of the experiments, mast cells were counted from the peritoneal fluid. The venom-induced pulmonary edema and the augmentation of PBG reflex were not observed in compound 48/80 treated animals. Further, mast cells in the peritoneal fluid were absent in this group as compared to vehicle treated group (29 ± 7.9 cells/mm³). These observations indicate that venom-induced pulmonary edema and augmentation of PBG reflexe are mediated through mast cells by involving H₁ receptors. Copyright © 2010 Elsevier Ltd. All rights reserved.

Adaptation to sensory-motor reflex perturbations is blind to the source of errors.

Science.gov (United States)

Hudson, Todd E; Landy, Michael S

2012-01-06

In the study of visual-motor control, perhaps the most familiar findings involve adaptation to externally imposed movement errors. Theories of visual-motor adaptation based on optimal information processing suppose that the nervous system identifies the sources of errors to effect the most efficient adaptive response. We report two experiments using a novel perturbation based on stimulating a visually induced reflex in the reaching arm. Unlike adaptation to an external force, our method induces a perturbing reflex within the motor system itself, i.e., perturbing forces are self-generated. This novel method allows a test of the theory that error source information is used to generate an optimal adaptive response. If the self-generated source of the visually induced reflex perturbation is identified, the optimal response will be via reflex gain control. If the source is not identified, a compensatory force should be generated to counteract the reflex. Gain control is the optimal response to reflex perturbation, both because energy cost and movement errors are minimized. Energy is conserved because neither reflex-induced nor compensatory forces are generated. Precision is maximized because endpoint variance is proportional to force production. We find evidence against source-identified adaptation in both experiments, suggesting that sensory-motor information processing is not always optimal.

Associative stimulation of the supraorbital nerve fails to induce timing-specific plasticity in the human blink reflex

DEFF Research Database (Denmark)

Zeuner, Kirsten E; Knutzen, Arne; Al-Ali, Asmaa

2010-01-01

Associative high-frequency electrical stimulation (HFS) of the supraorbital nerve in five healthy individuals induced long-term potentiation (LTP)-like or depression (LTD)-like changes in the human blink reflex circuit according to the rules of spike timing-dependent plasticity (Mao and Evinger...

The visual rooting reflex in individuals with autism spectrum disorders and co-occurring intellectual disability

NARCIS (Netherlands)

de Bildt, Annelies; Mulder, Erik J.; Van Lang, Natasja D. J.; de With, S. A. Jytte; Minderaa, Ruud B.; Stahl, Sherin S.; Anderson, George M.

The rooting reflex has long been studied by neurologists and developmentalists and is defined as an orientation toward tactile stimulation in the perioral region or visual stimulation near the face. Nearly, all previous reports of the visual rooting reflex (VRR) concern its presence in adults with

Physiological bases and treatment to the radiation-induced emetic reflex

International Nuclear Information System (INIS)

Mulen Napoles, Barbara M.; Torres Babie, Priscilla; Ropero Toirac, Ramon de J.

2002-01-01

In the course of the specific oncologic treatment, there are frequent complications such as nausea and vomiting. The radiation-induced emetic reflex depends on various factors: primary site of radiation, administered dose, fractioning, irradiated volume, the sensory and psychic characteristics of the patient as well as the chemotherapy association. It is known that the afferent path to the so-called center of vomiting is determined by chemical mediators, protuberance receptors of the intracranial pressure and the unleashing chemoreceptor zone. In radiation-induced emesis, the exact mechanism is yet to be determined but it is known that radiation stimulates the production of chemical mediators and serotonin released by enterochromaffin cells that act upon the center of vomiting and vagal nucleus. Most of patients who are exposed to irradiation of their upper and middle hemibody as well as all the patients exposed to whole-body irradiation present with nausea and vomiting. The therapeutical anti-emetic recommendations are based on the neurochemical control of vomiting and the emetogenic effect of radiotherapy. 5HT3 receptor-antagonists are evaluated as effective agents in the control of radiation-induced emesis

Human investigations into the exercise pressor reflex

DEFF Research Database (Denmark)

Secher, Niels H; Amann, Markus

2012-01-01

During exercise, neural input from skeletal muscles reflexly maintains or elevates blood pressure (BP) despite a maybe fivefold increase in vascular conductance. This exercise pressor reflex is illustrated by similar heart rate (HR) and BP responses to electrically induced and voluntary exercise....... The importance of the exercise pressor reflex for tight cardiovascular regulation during dynamic exercise is supported by studies using pharmacological blockade of lower limb muscle afferent nerves. These experiments show attenuation of the increase in BP and cardiac output when exercise is performed...... with attenuated neural feedback. Additionally, there is no BP response to electrically induced exercise with paralysing epidural anaesthesia or when similar exercise is evoked in paraplegic patients. Furthermore, BP decreases when electrically induced exercise is carried out in tetraplegic patients. The lack...

Reflex epilepsy: a review

Directory of Open Access Journals (Sweden)

Karim Nikkhah

2017-01-01

Full Text Available Interesting phenomena of reflex epileptic syndromes are characterized by epileptic seizures each one induced by specific stimulus with a variety of types. Simple triggers, which lead to seizures within seconds, are of sensory type (most commonly visual, most rarely tactile or proprioceptive stimuli. Complex triggers, which are mostly of cognitive type such as praxis, reading, talking, and music, usually induce the epileptic event within minutes. It should differ from what most epileptic patients report as provocative precipitants for seizures (such as emotional stress, fatigue, fever, sleep deprivation, alcohol, and menstrual cycle. The identification of a specific trigger is not only important for patients or their parents to avoid seizures, but also it might help neurologists to choose the most effective antiepileptic drug for each case. In addition, research in this area may possibly reveal some underlying pathophysiology of epileptic phenomena in the brain.In this review, we briefly introduce reported reflex epileptic seizures, their clinical features and management.

The role of capsaicin-sensitive muscle afferents in fatigue-induced modulation of the monosynaptic reflex in the rat.

Science.gov (United States)

Pettorossi, V E; Della Torre, G; Bortolami, R; Brunetti, O

1999-03-01

1. The role of group III and IV afferent fibres of the lateral gastrocnemious muscle (LG) in modulating the homonymous monosynaptic reflex was investigated during muscle fatigue in spinalized rats. 2. Muscle fatigue was induced by a series of increasing tetanic electrical stimuli (85 Hz, 600 ms) delivered to the LG muscle nerve. Series consisted of increasing train numbers from 1 to 60. 3. Potentials from the spinal cord LG motor pool and from the ventral root were recorded in response to proprioceptive afferent stimulation and analysed before and during tetanic muscle activations. Both the pre- and postsynaptic waves showed an initial enhancement and, after a '12-train' series, an increasing inhibition. 4. The enhancement of the responses to muscle fatiguing stimulation disappeared after L3-L6 dorsal root section, while a partial reflex inhibition was still present. Conversely, after section of the corresponding ventral root, there was only a reduction in the inhibitory effect. 5. The monosynaptic reflex was also studied in animals in which a large number of group III and IV muscle afferents were eliminated by injecting capsaicin (10 mM) into the LG muscle. As a result of capsaicin treatment, the fatigue-induced inhibition of the pre- and postsynaptic waves disappeared, while the response enhancement remained. 6. We concluded that the monosynaptic reflex inhibition, but not the enhancement, was mediated by those group III and IV muscle afferents that are sensitive to the toxic action of capsaicin. The afferents that are responsible for the response enhancement enter the spinal cord through the dorsal root, while those responsible for the inhibition enter the spinal cord through both the ventral and dorsal roots.

Sympathetic β-adrenergic mechanism in pudendal inhibition of nociceptive and non-nociceptive reflex bladder activity.

Science.gov (United States)

Kadow, Brian T; Lyon, Timothy D; Zhang, Zhaocun; Lamm, Vladimir; Shen, Bing; Wang, Jicheng; Roppolo, James R; de Groat, William C; Tai, Changfeng

2016-07-01

This study investigated the role of the hypogastric nerve and β-adrenergic mechanisms in the inhibition of nociceptive and non-nociceptive reflex bladder activity induced by pudendal nerve stimulation (PNS). In α-chloralose-anesthetized cats, non-nociceptive reflex bladder activity was induced by slowly infusing saline into the bladder, whereas nociceptive reflex bladder activity was induced by replacing saline with 0.25% acetic acid (AA) to irritate the bladder. PNS was applied at multiple threshold (T) intensities for inducing anal sphincter twitching. During saline infusion, PNS at 2T and 4T significantly (P reflex bladder activity. In addition to this peripheral mechanism, a central nervous system mechanism involving metabotropic glutamate 5 receptors also has a role in PNS inhibition. Copyright © 2016 the American Physiological Society.

Linear vestibuloocular reflex during motion along axes between nasooccipital and interaural

Science.gov (United States)

Tomko, David L.; Paige, Gary D.

1992-01-01

Linear vestibuloocular reflexes (LVORs), which stabilize retinal images by producing eye movements to compensate for linear head motion, are of two types: (1) responses to head tilt, which work primarily at low frequencies; and (2) responses to head translation, which act at higher frequencies. This work tested the hypothesis that reflexive eye movements would follow the same kinematics relative to the motion axis regardless of head orientation relative to linear motion. The experiments consisted of recording horizontal and vertical eye movements in squirrel monkeys during linear oscillations at 5 Hz along the head's nasooccipital (NO) axis and along axes lying within +/- 30 deg of the NO axis. It was found that LVORs followed the same kinematics regardless of the eye position in the head or the head orientation relative to motion.

Attentional modulation of reflex cough.

Science.gov (United States)

Janssens, Thomas; Silva, Mitchell; Davenport, Paul W; Van Diest, Ilse; Dupont, Lieven J; Van den Bergh, Omer

2014-07-01

Reflex cough is a defensive response generated in the brainstem in response to chemical and mechanical stimulation of the airways. However, converging evidence shows that reflex cough is also influenced by central neural control processes. In this study, we investigate whether reflex cough can be modulated by attentional focus on either external stimuli or internal cough-related stimuli. Healthy volunteers (N = 24; seven men; age range, 18-25 years) completed four blocks of citric acid-induced cough challenges while, simultaneously, auditory stimuli were presented. Within each block, four concentrations were administered (30, 100, 300 and 1,000 mM, randomized). During two subsequent blocks, participants focused their attention externally (counting tones). During the other two blocks, participants focused their attention internally (counting coughs). The order of attentional focus was counterbalanced across participants. Ratings of the urge to cough were collected after each challenge. Cough frequency was determined by audio recording. Cough frequency was higher when participants focused their attention internally vs externally (P Reflex cough can be modulated by attentional focus. Internally focused attention may be a mechanism involved in excessive (idiopathic) cough, while an external focus may be introduced as part of treatments targeting excessive cough.

Role of the brain stem in tibial inhibition of the micturition reflex in cats.

Science.gov (United States)

Ferroni, Matthew C; Slater, Rick C; Shen, Bing; Xiao, Zhiying; Wang, Jicheng; Lee, Andy; Roppolo, James R; de Groat, William C; Tai, Changfeng

2015-08-01

This study examined the role of the brain stem in inhibition of bladder reflexes induced by tibial nerve stimulation (TNS) in α-chloralose-anesthetized decerebrate cats. Repeated cystometrograms (CMGs) were performed by infusing saline or 0.25% acetic acid (AA) to elicit normal or overactive bladder reflexes, respectively. TNS (5 or 30 Hz) at three times the threshold (3T) intensity for inducing toe movement was applied for 30 min between CMGs to induce post-TNS inhibition or applied during the CMGs to induce acute TNS inhibition. Inhibition was evident as an increase in bladder capacity without a change in amplitude of bladder contractions. TNS applied for 30 min between saline CMGs elicited prolonged (>2 h) poststimulation inhibition that significantly (P reflexes but are not involved in inhibition of normal bladder reflexes. Copyright © 2015 the American Physiological Society.

Propranolol, but not naloxone, enhances spinal reflex bladder activity and reduces pudendal inhibition in cats.

Science.gov (United States)

Rogers, Marc J; Xiao, Zhiying; Shen, Bing; Wang, Jicheng; Schwen, Zeyad; Roppolo, James R; de Groat, William C; Tai, Changfeng

2015-01-01

This study examined the role of β-adrenergic and opioid receptors in spinal reflex bladder activity and in the inhibition induced by pudendal nerve stimulation (PNS) or tibial nerve stimulation (TNS). Spinal reflex bladder contractions were induced by intravesical infusion of 0.25% acetic acid in α-chloralose-anesthetized cats after an acute spinal cord transection (SCT) at the thoracic T9/T10 level. PNS or TNS at 5 Hz was applied to inhibit these spinal reflex contractions at 2 and 4 times the threshold intensity (T) for inducing anal or toe twitch, respectively. During a cystrometrogram (CMG), PNS at 2T and 4T significantly (P reflex bladder contractions. After administering propranolol (3 mg/kg iv, a β₁/β₂-adrenergic receptor antagonist), the effects of 2T and 4T PNS on bladder capacity were significantly (P reflex bladder contractions or PNS inhibition. At the end of experiments, hexamethonium (10 mg/kg iv, a ganglionic blocker) significantly (P reflex bladder contractions. This study indicates an important role of β₁/β₂-adrenergic receptors in pudendal inhibition and spinal reflex bladder activity. Copyright © 2015 the American Physiological Society.

A novel reflex cough testing device.

Science.gov (United States)

Fujiwara, Kazunori; Kawamoto, Katsuyuki; Shimizu, Yoko; Fukuhara, Takahiro; Koyama, Satoshi; Kataoka, Hideyuki; Kitano, Hiroya; Takeuchi, Hiromi

2017-01-18

The reflex cough test is useful for detecting silent aspiration, a risk factor for aspiration pneumonia. However, assessing the risk of aspiration pneumonia requires measuring not only the cough reflex but also cough strength. Currently, no reflex cough testing device is available that can directly measure reflex cough strength. We therefore developed a new testing device that can easily and simultaneously measure cough strength and the time until the cough reflex, and verified whether screening with this new instrument is feasible for evaluating the risk of aspiration pneumonia. This device consists of a special pipe with a double lumen, a nebulizer, and an electronic spirometer. We used a solution of prescription-grade L-tartaric acid to initiate the cough reflex. The solution was inhaled through a mouthpiece as a microaerosol produced by an ultrasonic nebulizer. The peak cough flow (PCF) of the induced cough was measured with the spirometer. The 70 patients who participated in this study comprised 49 patients without a history of pneumonia (group A), 21 patients with a history of pneumonia (group B), and 10 healthy volunteers (control group). With the novel device, PCF and time until cough reflex could be measured without adverse effects. The PCF values were 118.3 ± 64.0 L/min, 47.7 ± 38.5 L/min, and 254.9 ± 83.8 L/min in group A, group B, and the control group, respectively. The PCF of group B was significantly lower than that of group A and the control group (p reflex was 4.2 ± 5.9 s, 7.0 ± 7.0 s, and 1 s in group A, group B, and the control group, respectively. This duration was significantly longer for groups A and B than for the control group (A: p reflex and the strength of involuntary coughs for assessment of patients at risk of aspiration pneumonia.

Diversity in goal orientation, team reflexivity, and team performance

NARCIS (Netherlands)

Pieterse, Anne Nederveen; van Knippenberg, Daan; van Ginkel, Wendy P.

Although recent research highlights the role of team member goal orientation in team functioning, research has neglected the effects of diversity in goal orientation. In a laboratory study with groups working on a problem-solving task, we show that diversity in learning and performance orientation

Shear induced orientation of edible fat and chocolate crystals

Science.gov (United States)

Mazzanti, Gianfranco; Welch, Sarah E.; Marangoni, Alejandro G.; Sirota, Eric B.; Idziak, Stefan H. J.

2003-03-01

Shear-induced orientation of fat crystallites was observed during crystallization of cocoa butter, milk fat, stripped milk fat and palm oil. This universal effect was observed in systems crystallized under high shear. The minor polar components naturally present in milk fat were found to decrease the shear-induced orientation effect in this system. The competition between Brownian and shear forces, described by the Peclet number, determines the crystallite orientation. The critical radius size, from the Gibbs-Thomson equation, provides a tool to understand the effect of shear at the onset stages of crystallization.

Soleus and lateral gastrocnemius H-reflexes during standing with unstable footwear.

Science.gov (United States)

Friesenbichler, Bernd; Lepers, Romuald; Maffiuletti, Nicola A

2015-05-01

Unstable footwear has been shown to increase lower extremity muscle activity, but the reflex response to perturbations induced by this intervention is unknown. Twenty healthy subjects stood in stable and unstable footwear conditions (presented randomly) while H-reflex amplitude and background muscle activity were measured in the soleus and lateral gastrocnemius (LG) muscles. Wearing unstable footwear resulted in larger H-reflexes (normalized to the maximal M-wave) for the LG (+12%; P = 0.025), but not for the soleus (+4%; P > 0.05). Background activity of both muscles was significantly higher in the unstable condition. The H-reflex facilitation observed with unstable footwear was unexpected, as challenging postural conditions usually result in reflex depression. Increased muscle activity, decreased presynaptic inhibition, and/or more forward postural position may have (over-)compensated the expected reflex depression. Differences between LG and soleus H-reflex modulation may be due to diverging motor unit recruitment thresholds. © 2015 Wiley Periodicals, Inc.

Mechanisms of two-color laser-induced field-free molecular orientation.

Science.gov (United States)

Spanner, Michael; Patchkovskii, Serguei; Frumker, Eugene; Corkum, Paul

2012-09-14

Two mechanisms of two-color (ω+2ω) laser-induced field-free molecular orientation, based on the hyperpolarizability and ionization depletion, are explored and compared. The CO molecule is used as a computational example. While the hyperpolarizability mechanism generates small amounts of orientation at intensities below the ionization threshold, ionization depletion quickly becomes the dominant mechanism as soon as ionizing intensities are reached. Only the ionization mechanism leads to substantial orientation (e.g., on the order of ≳0.1). For intensities typical of laser-induced molecular alignment and orientation experiments, the two mechanisms lead to robust, characteristic timings of the field-free orientation wave-packet revivals relative to the alignment revivals and the revival time. The revival timings can be used to detect the active orientation mechanism experimentally.

The Disappearing Audience and Reflexive Visibility

OpenAIRE

Katerina Girginova

2016-01-01

Contrary to popular opinion and some academic writing that celebrates the renewed visibility of new media audiences, this essay argues that they are increasingly going into retreat. To understand how new media audiences “disappear” from view of one another, I borrow from Brighenti’s typology of visibility and develop the idea of “reflexive visibility.” The latter describes the ability to socially orient ourselves in a digital environment through the textual and contextual cues of others—an ac...

No evidence hip joint angle modulates intrinsically produced stretch reflex in human hopping.

Science.gov (United States)

Gibson, W; Campbell, A; Allison, G

2013-09-01

Motor output in activities such as walking and hopping is suggested to be mediated neurally by purported stretch reflex augmentation of muscle output. Reflex EMG activity during these tasks has been frequently investigated in the soleus muscle; with alterations in reflex amplitude being associated with changes in hip joint angle/phase of the gait cycle. Previous work has focussed on reflex activity induced by an artificial perturbation or by induction of H-reflexes. As such, it is currently unknown if stretch reflex activity induced intrinsically (as part of the task) is modulated by changes in hip joint angle. This study investigated whether hip joint angle modulated reflex EMG 'burst' activity during a hopping task performed on a custom-built partially reclined sleigh. Ten subjects participated; EMG and kinematic data (VICON motor capture system) was collected for each hop cycle. Participants completed 5 sets of 30s of self-paced hopping in (1) hip neutral and (2) hip 60° flexion conditions. There was no difference in EMG 'burst' activity or in sagittal plane kinematics (knee/ankle) in the hopping task between the two conditions. The results indicate that during a functional task such as hopping, changes in hip angle do not alter the stretch reflex-like activity associated with landing. Copyright © 2013 Elsevier B.V. All rights reserved.

Pure nuclear reflexes and combined hyperfine interactions in YIG

Energy Technology Data Exchange (ETDEWEB)

Winkler, H; Eisberg, R; Alp, E; Rueffer, R; Gerdau, E; Lauer, S; Trautwein, A X; Grodzicki, M; Vera, A

1983-01-01

Moessbauer spectra of oriented YIG single crystals were taken and the numerical analysis using the transmission integral yielded a consistent set of hyperfine interaction parameters. They are in good agreement with theoretical values obtained by MO-calculations which included clusters up to 62 ions. Finally pure nuclear reflexes are predicted for single crystals and two theoretical spectra are given.

Effect of e-Cigarette Use on Cough Reflex Sensitivity.

Science.gov (United States)

Dicpinigaitis, Peter V; Lee Chang, Alfredo; Dicpinigaitis, Alis J; Negassa, Abdissa

2016-01-01

E-cigarettes (e-cigs) have attained widespread popularity, yet knowledge of their physiologic effects remains minimal. The aim of this study was to evaluate the effect of a single exposure to e-cig vapor on cough reflex sensitivity. Thirty healthy nonsmokers underwent cough reflex sensitivity measurement using capsaicin cough challenge at baseline, 15 min, and 24 h after e-cig exposure (30 puffs 30 s apart). The end point of cough challenge is the concentration of capsaicin inducing five or more coughs (C5). The number of coughs induced by each e-cig inhalation was counted. A subgroup of subjects (n = 8) subsequently underwent an identical protocol with a non-nicotine-containing e-cig. Cough reflex sensitivity was significantly inhibited (C5 increased) 15 min after e-cig use (?0.29; 95% CI, ?0.43 to ?0.15; P < .0001); 24 h later, C5 returned to baseline (0.24; 95% CI, 0.10-0.38; P = .0002 vs post-15-min value). A subgroup of eight subjects demonstrating the largest degree of cough reflex inhibition had no suppression after exposure to a non-nicotine-containing e-cig (P = .0078 for comparison of ?C5 after nicotine vs non-nicotine device). Furthermore, more coughing was induced by the nicotine-containing vs non-nicotine-containing device (P = .0156). A single session of e-cig use, approximating nicotine exposure of one tobacco cigarette, induces significant inhibition of cough reflex sensitivity. Exploratory analysis of a subgroup of subjects suggests that nicotine is responsible for this observation. Our data, consistent with previous studies of nicotine effect, suggest a dual action of nicotine: an immediate, peripheral protussive effect and a delayed central antitussive effect. ClinicalTrials.gov; No.: NCT02203162; URL: www.clinicaltrials.gov. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Inhibition of micturition reflex by activation of somatic afferents in posterior femoral cutaneous nerve.

Science.gov (United States)

Tai, Changfeng; Shen, Bing; Mally, Abhijith D; Zhang, Fan; Zhao, Shouguo; Wang, Jicheng; Roppolo, James R; de Groat, William C

2012-10-01

This study determined if activation of somatic afferents in posterior femoral cutaneous nerve (PFCN) could modulate the micturition reflex recorded under isovolumetric conditions in α-chloralose anaesthetized cats. PFCN stimulation inhibited reflex bladder activity and significantly (P acid (AA). The optimal frequency for PFCN stimulation-induced bladder inhibition was between 3 and 10 Hz, and a minimal stimulation intensity of half of the threshold for inducing anal twitching was required. Bilateral pudendal nerve transection eliminated PFCN stimulation-induced anal twitching but did not change the stimulation-induced bladder inhibition, excluding the involvement of pudendal afferent or efferent axons in PFCN afferent inhibition.Mechanical or electrical stimulation on the skin surface in the PFCN dermatome also inhibited bladder activity. Prolonged (2 × 30 min) PFCN stimulation induced a post-stimulation inhibition that persists for at least 2 h. This study revealed a new cutaneous-bladder reflex activated by PFCN afferents. Although the mechanisms and physiological functions of this cutaneous-bladder reflex need to be further studied, our data raise the possibility that stimulation of PFCN afferents might be useful clinically for the treatment of overactive bladder symptoms.

From globalist to cosmopolitan learning: on the reflexive modernization of teacher education

Directory of Open Access Journals (Sweden)

Niclas Rönnström

2013-01-01

Full Text Available In this article, I discuss teacher education reform and the work of teachers in light of globalization and reflexive modernization. Increasing globalization has meant changed conditions for national education traditionally geared toward nation building and to the nationalizing of lifeworlds. It is assumed that the global economy has made knowledge and lifelong learning essential to economic growth, and governments have considered their citizens, teachers, and schools to be poorly trained for the demands of knowledge economies. Consequently, nation-states have invested massively in teacher education because of the vital role effective high-quality teachers are expected to play in preparation for working on global markets and for the competitive edge of nations. However, recent teacher education reform can be criticized for a one-sided orientation toward principles of economic growth, effectiveness, and competitiveness at the expense of other important educational aims, such as the development of reflective and communicative capacities and education for cosmopolitan citizenship. Moreover, recent teacher education reform in various nation-states seems to neglect how processes of reflexive modernization profoundly change schools, society, and the teaching situation, and undermine the principles that marked earlier phases of nation-centered modernization. I discuss teacher education and the work of teachers as reflexive modern practices and phenomena within the framework of critical social theory, and I mainly use Ulrich Beck's theory of reflexive modernization. I argue that increased reflexivity, institutionalized individualization, and cosmopolitization constitute reasons for the re-contextualization of teacher education away from the uncritical influence of the primacy of the economy, instrumental rationalization, and other principles of modernization that are now running dry. In the final part, I discuss the importance of moving from a mainly

Involvement of ERK phosphorylation in brainstem neurons in modulation of swallowing reflex in rats

Science.gov (United States)

Tsujimura, Takanori; Kondo, Masahiro; Kitagawa, Junichi; Tsuboi, Yoshiyuki; Saito, Kimiko; Tohara, Haruka; Ueda, Koichiro; Sessle, Barry J; Iwata, Koichi

2009-01-01

In order to evaluate the neuronal mechanisms underlying functional abnormalities of swallowing in orofacial pain patients, this study investigated the effects of noxious orofacial stimulation on the swallowing reflex, phosphorylated extracellular signal-regulated kinase (pERK) and γ-aminobutyric acid (GABA) immunohistochemical features in brainstem neurons, and also analysed the effects of brainstem lesioning and of microinjection of GABA receptor agonist or antagonist into the nucleus tractus solitarii (NTS) on the swallowing reflex in anaesthetized rats. The swallowing reflex elicited by topical administration of distilled water to the pharyngolaryngeal region was inhibited after capsaicin injection into the facial (whisker pad) skin or lingual muscle. The capsaicin-induced inhibitory effect on the swallowing reflex was itself depressed after the intrathecal administration of MAPK kinase (MEK) inhibitor. No change in the capsaicin-induced inhibitory effect was observed after trigeminal spinal subnucleus caudalis lesioning, but the inhibitory effect was diminished by paratrigeminal nucleus (Pa5) lesioning. Many pERK-like immunoreactive neurons in the NTS showed GABA immunoreactivity. The local microinjection of the GABAA receptor agonist muscimol into the NTS produced a significant reduction in swallowing reflex, and the capsaicin-induced depression of the swallowing reflex was abolished by microinjection of the GABAA receptor antagonist bicuculline into the NTS. The present findings suggest that facial skin–NTS, lingual muscle–NTS and lingual muscle–Pa5–NTS pathways are involved in the modulation of swallowing reflex by facial and lingual pain, respectively, and that the activation of GABAergic NTS neurons is involved in the inhibition of the swallowing reflex following noxious stimulation of facial and intraoral structures. PMID:19124539

Involvement of ERK phosphorylation in brainstem neurons in modulation of swallowing reflex in rats.

Science.gov (United States)

Tsujimura, Takanori; Kondo, Masahiro; Kitagawa, Junichi; Tsuboi, Yoshiyuki; Saito, Kimiko; Tohara, Haruka; Ueda, Koichiro; Sessle, Barry J; Iwata, Koichi

2009-02-15

In order to evaluate the neuronal mechanisms underlying functional abnormalities of swallowing in orofacial pain patients, this study investigated the effects of noxious orofacial stimulation on the swallowing reflex, phosphorylated extracellular signal-regulated kinase (pERK) and gamma-aminobutyric acid (GABA) immunohistochemical features in brainstem neurons, and also analysed the effects of brainstem lesioning and of microinjection of GABA receptor agonist or antagonist into the nucleus tractus solitarii (NTS) on the swallowing reflex in anaesthetized rats. The swallowing reflex elicited by topical administration of distilled water to the pharyngolaryngeal region was inhibited after capsaicin injection into the facial (whisker pad) skin or lingual muscle. The capsaicin-induced inhibitory effect on the swallowing reflex was itself depressed after the intrathecal administration of MAPK kinase (MEK) inhibitor. No change in the capsaicin-induced inhibitory effect was observed after trigeminal spinal subnucleus caudalis lesioning, but the inhibitory effect was diminished by paratrigeminal nucleus (Pa5) lesioning. Many pERK-like immunoreactive neurons in the NTS showed GABA immunoreactivity. The local microinjection of the GABA(A) receptor agonist muscimol into the NTS produced a significant reduction in swallowing reflex, and the capsaicin-induced depression of the swallowing reflex was abolished by microinjection of the GABA(A) receptor antagonist bicuculline into the NTS. The present findings suggest that facial skin-NTS, lingual muscle-NTS and lingual muscle-Pa5-NTS pathways are involved in the modulation of swallowing reflex by facial and lingual pain, respectively, and that the activation of GABAergic NTS neurons is involved in the inhibition of the swallowing reflex following noxious stimulation of facial and intraoral structures.

Reflex epilepsy: triggers and management strategies

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Okudan ZV

2018-01-01

Full Text Available Zeynep Vildan Okudan,1 Çiğdem Özkara2 1Department of Neurology, Bakirkoy Dr Sadi Konuk Education and Research Hospital, 2Department of Neurology and Clinical Neurophysiology, Cerrahpasa Faculty of Medicine, University of Istanbul, Istanbul, Turkey Abstract: Reflex epilepsies (REs are identified as epileptic seizures that are consistently induced by identifiable and objective-specific triggers, which may be an afferent stimulus or by the patient’s own activity. RE may have different subtypes depending on the stimulus characteristic. There are significant clinical and electrophysiologic differences between different RE types. Visual stimuli-sensitive or photosensitive epilepsies constitute a large proportion of the RE and are mainly related to genetic causes. Reflex epilepsies may present with focal or generalized seizures due to specific triggers, and sometimes seizures may occur spontaneously. The stimuli can be external (light flashes, hot water, internal (emotion, thinking, or both and should be distinguished from triggering precipitants, which most epileptic patients could report such as emotional stress, sleep deprivation, alcohol, and menstrual cycle. Different genetic and acquired factors may play a role in etiology of RE. This review will provide a current overview of the triggering factors and management of reflex seizures. Keywords: seizure, reflex epilepsy, photosensitivity, hot water, reading, thinking

Being reflexive in qualitative grounded theory: discussion and application of a model of reflexivity.

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Engward, Hilary; Davis, Geraldine

2015-07-01

A discussion of the meaning of reflexivity in research with the presentation of examples of how a model of reflexivity was used in a grounded theory research project. Reflexivity requires the researcher to make transparent the decisions they make in the research process and is therefore important in developing quality in nursing research. The importance of being reflexive is highlighted in the literature in relation to nursing research, however, practical guidance as to how to go about doing research reflexively is not always clearly articulated. This is a discussion paper. The concept of reflexivity in research is explored using the Alvesson and Skoldberg model of reflexivity and practical examples of how a researcher developed reflexivity in a grounded theory project are presented. Nurse researchers are encouraged to explore and apply the concept of reflexivity in their research practices to develop transparency in the research process and to increase robustness in their research. The Alvesson and Skoldberg model is of value in applying reflexivity in qualitative nursing research, particularly in grounded theory research. Being reflexive requires the researcher to be completely open about decisions that are made in the research process. The Alvesson and Skolberg model of reflexivity is a useful model that can enhance reflexivity in the research process. It can be a useful practical tool to develop reflexivity in grounded theory research. © 2015 John Wiley & Sons Ltd.

Plasticity of the human otolith-ocular reflex

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Wall, C. 3rd; Smith, T. R.; Furman, J. M.

1992-01-01

The eye movement response to earth vertical axis rotation in the dark, a semicircular canal stimulus, can be altered by prior exposure to combined visual-vestibular stimuli. Such plasticity of the vestibulo-ocular reflex has not been described for earth horizontal axis rotation, a dynamic otolith stimulus. Twenty normal human subjects underwent one of two types of adaptation paradigms designed either to attenuate or enhance the gain of the semicircular canal-ocular reflex prior to undergoing otolith-ocular reflex testing with horizontal axis rotation. The adaptation paradigm paired a 0.2 Hz sinusoidal rotation about a vertical axis with a 0.2 Hz optokinetic stripe pattern that was deliberately mismatched in peak velocity. Pre- and post-adaptation horizontal axis rotations were at 60 degrees/s in the dark and produced a modulation in the slow component velocity of nystagmus having a frequency of 0.17 Hz due to putative stimulation of the otolith organs. Results showed that the magnitude of this modulation component response was altered in a manner similar to the alteration in semicircular canal-ocular responses. These results suggest that physiologic alteration of the vestibulo-ocular reflex using deliberately mismatched visual and semicircular canal stimuli induces changes in both canal-ocular and otolith-ocular responses. We postulate, therefore, that central nervous system pathways responsible for controlling the gains of canal-ocular and otolith-ocular reflexes are shared.

Role of duodenal mucosal nerve endings in the acid-induced duodenogastric sensorimotor reflex: effect of benzocaine in healthy humans.

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Vanuytsel, T; Karamanolis, G; Vos, R; Van Oudenhove, L; Farré, R; Tack, J

2013-05-01

Duodenal acid exposure induces a duodenogastric reflex resulting in gastric relaxation, inhibition of antral motility, and sensitization of the proximal stomach to distension. Duodenal hypersensitivity to acid has been identified as a potential pathogenic mechanism in functional dyspepsia. The nature and localization of the duodenal acid-sensitive receptors are still elusive. We hypothesize that acid directly activates superficial afferent nerve endings in the duodenal mucosa, triggering the duodenogastric reflex. In a double-blind, randomized, crossover study in 13 healthy volunteers, benzocaine, a local anesthetic, vs saline was perfused in the duodenum 15 min before duodenal acid perfusion. Gastric responses were monitored by a barostat. Stepwise isobaric gastric distensions were performed before and during acid perfusion. Symptoms were evaluated by visual analogue scales for six dyspeptic symptoms and an overall perception score. Benzocaine perfusion caused a relaxation of the stomach prior to duodenal acidification, indicating the existence of an excitatory duodenogastric tone. Pretreatment of the duodenum with benzocaine reduced the acid-induced gastric relaxation by 50% and abolished the inhibition of phasic motility of the proximal stomach. Finally, sensitization to distension was more pronounced in the benzocaine condition because of higher proximal gastric volumes. These findings support a model in which different neuronal subpopulations are responsible for the motor and sensory limb of the acid-sensitive duodenogastric reflex, making benzocaine an unsuitable drug to treat duodenal hypersensitivity to acid. These data provide more insight in the contribution of duodenal neuronal input to gastric physiology in the fasting state. © 2013 Blackwell Publishing Ltd.

Nociceptive flexion reflexes during analgesic neurostimulation in man.

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García-Larrea, L; Sindou, M; Mauguière, F

1989-11-01

Nociceptive flexion reflexes of the lower limbs (RIII responses) have been studied in 21 patients undergoing either epidural (DCS, n = 16) or transcutaneous (TENS, n = 5) analgesic neurostimulation (AN) for chronic intractable pain. Flexion reflex RIII was depressed or suppressed by AN in 11 patients (52.4%), while no modification was observed in 9 cases and a paradoxical increase during AN was evidenced in 1 case. In all but 2 patients, RIII changes were rapidly reversible after AN interruption. RIII depression was significantly associated with subjective pain relief, as assessed by conventional self-rating; moreover, in 2 patients it was possible to ameliorate the pain-suppressing effects of AN by selecting those stimulation parameters (intensity and frequency) that maximally depressed nociceptive reflex RIII. We recorded 2 cases of RIII attenuation after contralateral neurostimulation. AN appeared to affect nociceptive reflexes rather selectively, with no or very little effect on other cutaneous, non-nociceptive responses. Recording of RIII reflexes is relatively simple to implement as a routine paraclinical procedure. It facilitates the objective assessment of AN efficacy and may help to choose the most appropriate parameters of neurostimulation. In addition, RIII behavior in patients could be relevant to the understanding of some of the mechanisms involved in AN-induced pain relief.

From Incidental, Mechanically-Induced Arrhythmias to Reflex-Defined Arrhythmogenicity: On The Track of The Ternary Reflex System Resemblance to The "Infancy" of New Era or Rediscovery.

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Stirbys, Petras

2016-01-01

The underlying pathophysiology of supraventricular and ventricular arrhythmias remains a matter of intense investigation. Though evolving, the contemporary explanations do not encompass all aspects of arrhythmogenicity. An improved understanding of arrhythmia substrate is needed to augment therapeutic capabilities. Our observation and literature sources demonstrate relatively high incidence of transitory arrhythmias which are non-intentionally generated by the endocardial lead/catheter manipulation. These findings are interesting and potentially may crystallize the reflex-dependent proarrhythmic cardiac activity. Herein we suggest the "reflexogenic arrhythmogenicity" concept extending an overall spectrum of known hypotheses. Cardiovascular reflex action can be categorized into three-tiered levels - intra-cellular, inter-cellular and inter-organic. The first two levels of the triplicate system reside within the cardiac anatomical landmarks (in fact intramurally, intra-organically), however the third one implicates central (cerebral) activity which boomerangs back via centripetal and centrifugal connections. These levels likely compose synoptic ternary reflex set system which may be validated in future studies. To hypothesize, coordinated mutual reciprocity of reflex activity results in stabilization of heart rhythm in robust heart. Any stressful cardiac event may lead to the shift of the rhythm toward unfavorable clinical entity probably via the loss of the influence of dominant reflex. Overall, an interaction and likely intrinsic inter-tiered competition along with possible interplay between physiological and pathological reflexes may be treated as contributing factors for the inception and maintaining of arrhythmias and cardiac performance as well. These assumptions await further documentation. If such a tenet were recognized, the changes in the clinical approach to arrhythmia management might be anticipated, preferably by selective reflex suppression or

Etnography and Reflexivity

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Mario Cardano

2014-01-01

Full Text Available This essay deals with a relevant and controversial topic – objectivity in ethnographic research. More specifically, I would like to examine how reflexive procedures, more precisely “reflexive account”, can increase the robustness of results gained through an ethnographic research. The essay is organized in five parts. I will start by giving a preliminary definition of the two key concepts which are at the center of the analysis – objectivity and reflexivity. I will then give a brief description of the epistemological framework in which the proposed conceptions of objectivity and reflexivity are located. Thirdly, I move on to consider the epistemic status of ethnographic research, and will emphasize that ethnographies are not just “theory-laden”, as many writers have stated, but also “praxis” or “procedure laden”. In other words, I will stress that it is not only theories which are inevitably embedded in research, influencing how observations can be made; much the same can also be said of the concrete research practices which contribute to determine the experience of the ethnographer and its representation in a text. Fourthly, I will discuss why it is useful to employ reflexive practices, and then immediately afterwards will illustrate the ways in which reflexive descriptions can contribute to greater objectivity of ethnographic accounts. In conclusion, I will discuss a number of objections which have been raised against this use of reflexivity.

Reflexive reasoning for distributed real-time systems

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Goldstein, David

1994-01-01

This paper discusses the implementation and use of reflexive reasoning in real-time, distributed knowledge-based applications. Recently there has been a great deal of interest in agent-oriented systems. Implementing such systems implies a mechanism for sharing knowledge, goals and other state information among the agents. Our techniques facilitate an agent examining both state information about other agents and the parameters of the knowledge-based system shell implementing its reasoning algorithms. The shell implementing the reasoning is the Distributed Artificial Intelligence Toolkit, which is a derivative of CLIPS.

Competition Between Endogenous and Exogenous Orienting of Visual Attention

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Berger, Andrea; Henik, Avishai; Rafal, Robert

2005-01-01

The relation between reflexive and voluntary orienting of visual attention was investigated with 4 experiments: a simple detection task, a localization task, a saccade toward the target task, and a target identification task in which discrimination difficulty was manipulated. Endogenous and exogenous orienting cues were presented in each trial and…

The Gateway Reflex, a Novel Neuro-Immune Interaction for the Regulation of Regional Vessels

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Yuki Tanaka

2017-10-01

Full Text Available The gateway reflex is a new phenomenon that explains how immune cells bypass the blood–brain barrier to infiltrate the central nervous system (CNS and trigger neuroinflammation. To date, four examples of gateway reflexes have been discovered, each described by the stimulus that evokes the reflex. Gravity, electricity, pain, and stress have all been found to create gateways at specific regions of the CNS. The gateway reflex, the most recently discovered of the four, has also been shown to upset the homeostasis of organs in the periphery through its action on the CNS. These reflexes provide novel therapeutic targets for the control of local neuroinflammation and organ function. Each gateway reflex is activated by different neural activations and induces inflmammation at different regions in the CNS. Therefore, it is theoretically possible to manipulate each independently, providing a novel therapeutic strategy to control local neuroinflammation and peripheral organ homeostasis.

Muscle and reflex changes with varying joint angle in hemiparetic stroke

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Alibiglou Laila

2008-02-01

Full Text Available Abstract Background Despite intensive investigation, the origins of the neuromuscular abnormalities associated with spasticity are not well understood. In particular, the mechanical properties induced by stretch reflex activity have been especially difficult to study because of a lack of accurate tools separating reflex torque from torque generated by musculo-tendinous structures. The present study addresses this deficit by characterizing the contribution of neural and muscular components to the abnormally high stiffness of the spastic joint. Methods Using system identification techniques, we characterized the neuromuscular abnormalities associated with spasticity of ankle muscles in chronic hemiparetic stroke survivors. In particular, we systematically tracked changes in muscle mechanical properties and in stretch reflex activity during changes in ankle joint angle. Modulation of mechanical properties was assessed by applying perturbations at different initial angles, over the entire range of motion (ROM. Experiments were performed on both paretic and non-paretic sides of stroke survivors, and in healthy controls. Results Both reflex and intrinsic muscle stiffnesses were significantly greater in the spastic/paretic ankle than on the non-paretic side, and these changes were strongly position dependent. The major reflex contributions were observed over the central portion of the angular range, while the intrinsic contributions were most pronounced with the ankle in the dorsiflexed position. Conclusion In spastic ankle muscles, the abnormalities in intrinsic and reflex components of joint torque varied systematically with changing position over the full angular range of motion, indicating that clinical perceptions of increased tone may have quite different origins depending upon the angle where the tests are initiated. Furthermore, reflex stiffness was considerably larger in the non-paretic limb of stroke patients than in healthy control subjects

The Disappearing Audience and Reflexive Visibility

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Katerina Girginova

2016-08-01

Full Text Available Contrary to popular opinion and some academic writing that celebrates the renewed visibility of new media audiences, this essay argues that they are increasingly going into retreat. To understand how new media audiences “disappear” from view of one another, I borrow from Brighenti’s typology of visibility and develop the idea of “reflexive visibility.” The latter describes the ability to socially orient ourselves in a digital environment through the textual and contextual cues of others—an activity that is of utmost importance not only to researchers wishing to “see” various audiences but also for audiences writ large, wishing to know themselves.

The Use of Restoring Resources of the Survival Roles and Reflex Patterns in MNRI® (Reflex Integration Interactive Training of Personality Growth and Interpersonal Relations

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Masgutova S.K.

2017-12-01

Full Text Available Personality growth as a socio-psychological problem is a multi-complex phenomenon that targets Self-identity, Self-actualization, and other areas. During the last decade scientists started studying other factors limiting the personality growth, such as stress and post-trauma. However, the Survival Roles, the socio-individual patterns based on neurophysiological and psychological defense mechanisms blocking the personality Self-actualization, social interaction and professional business qualities, are rarely discussed. Thus this study based on Survival Roles may extend the personality growth oriented concepts and therapy modality tools. This study showed a correlation between Survival Role patterns, stress resilience, and survival reflexes (integrative units of the nervous system functions. Comparative data on 464 business professionals from high management jobs (Study Group — n=340, and Control Group — n=124 participated in this research which found 70.9 % (n=329 of the total group was in stress. This stress activated socio-individual Survival Roles and protective reflex patterns which responded with reactivity, over-protection, non-constructive interactions with others and limited business strategies. The MNRI® reflex integrative training used in this study demonstrated improvement of functions of the protective reflex patterns effected positively the survival mechanisms including increased stress resilience, and decreased negative effect of Survival Roles. MNRI® proposes a new paradigm in the realm of personality growth and socio-interpersonal activity, and supports the neurophysiological aspects to optimize the overall quality of life of business professionals from a variety of high management business areas.

Oral sapropterin augments reflex vasoconstriction in aged human skin through noradrenergic mechanisms.

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Stanhewicz, Anna E; Alexander, Lacy M; Kenney, W Larry

2013-10-01

Reflex vasoconstriction is attenuated in aged skin due to a functional loss of adrenergic vasoconstriction. Bioavailability of tetrahydrobiopterin (BH4), an essential cofactor for catecholamine synthesis, is reduced with aging. Locally administered BH4 increases vasoconstriction through adrenergic mechanisms in aged human skin. We hypothesized that oral sapropterin (Kuvan, a pharmaceutical BH4) would augment vasoconstriction elicited by whole-body cooling and tyramine perfusion in aged skin. Ten healthy subjects (age 75 ± 2 yr) ingested sapropterin (10 mg/kg) or placebo in a randomized, double-blind crossover design. Venous blood samples were collected prior to, and 3 h following ingestion. Three intradermal microdialysis fibers were placed in the forearm skin for local delivery of 1) lactated Ringer, 2) 5 mM BH4, and 3) 5 mM yohimbine + 1 mM propranolol (Y+P; to inhibit adrenergic vasoconstriction). Red cell flux was measured at each site by laser-Doppler flowmetry (LDF) as reflex vasoconstriction was induced by lowering and then clamping whole-body skin temperature (Tsk) using a water-perfused suit. Following whole-body cooling, subjects were rewarmed and 1 mM tyramine was perfused at each site to elicit endogenous norepinephrine release from the perivascular nerve terminal. Cutaneous vascular conductance was calculated as CVC = LDF/mean arterial pressure and expressed as change from baseline (ΔCVC). Plasma BH4 was elevated 3 h after ingestion of sapropterin (43.8 ± 3 vs. 19.1 ± 2 pmol/ml; P effect on reflex vasoconstriction at the BH4-perfused or Y+P-perfused sites. Sapropterin increased pharmacologically induced vasoconstriction at the Ringer site (-0.19 ± 0.03 vs. -0.08 ± 0.02 ΔCVC; P = 0.01). There was no difference in pharmacologically induced vasoconstriction between treatments at the BH4-perfused site (-0.16 ± 0.04 vs. -0.14 ± 0.03 ΔCVC; P = 0.60) or the Y+P-perfused site (-0.05 ± 0.02 vs.-0.06 ± 0.02 ΔCVC; P = 0.79). Sapropterin increases

Reflex epileptic mechanisms in humans: Lessons about natural ictogenesis.

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Wolf, Peter

2017-06-01

The definition of reflex epileptic seizures is that specific seizure types can be triggered by certain sensory or cognitive stimuli. Simple triggers are sensory (most often visual, more rarely tactile or proprioceptive; simple audiogenic triggers in humans are practically nonexistent) and act within seconds, whereas complex triggers like praxis, reading and talking, and music are mostly cognitive and work within minutes. The constant relation between a qualitatively, often even quantitatively, well-defined stimulus and a specific epileptic response provides unique possibilities to investigate seizure generation in natural human epilepsies. For several reflex epileptic mechanisms (REMs), this has been done. Reflex epileptic mechanisms have been reported less often in focal lesional epilepsies than in idiopathic "generalized" epilepsies (IGEs) which are primarily genetically determined. The key syndrome of IGE is juvenile myoclonic epilepsy (JME), where more than half of the patients present reflex epileptic traits (photosensitivity, eye closure sensitivity, praxis induction, and language-induced orofacial reflex myocloni). Findings with multimodal investigations of cerebral function concur to indicate that ictogenic mechanisms in IGEs largely (ab)use preexisting functional anatomic networks (CNS subsystems) normally serving highly complex physiological functions (e.g., deliberate complex actions and linguistic communication) which supports the concept of system epilepsy. Whereas REMs in IGEs, thus, are primarily function-related, in focal epilepsies, they are primarily localization-related. This article is part of a Special Issue entitled "Genetic and Reflex Epilepsies, Audiogenic Seizures and Strains: From Experimental Models to the Clinic". Copyright © 2015 Elsevier Inc. All rights reserved.

Reflexivity in qualitative research

DEFF Research Database (Denmark)

Evans, Adam Brian; Nistrup, Anne; Henderson, Hannah

2018-01-01

There has been something of a “reflexive shift” in sociological research. Sociological researchers are increasingly encouraged to be “present” within their work, and to recognize their own role in structuring the entire research process. One way to achieve this is through engagement in reflexive...... practice, that is, to reflect on our own values, beliefs, and biographies. It can be difficult to know exactly how a researcher should engage in these practices, however. Here, we discuss our reflexive practice in two case studies, both which utilized the same figurational theoretical framework...... Kingdom. Reflexive practice in both studies was affected by researcher biographies and by study design. In Study 1, both researchers were reasonably detached from the study context, the theoretical framework was in place from the very beginning, and reflexive practice was embedded in the study design...

Cardiac effects of electrically induced intrathoracic autonomic reflexes.

Science.gov (United States)

Armour, J A

1988-06-01

Electrical stimulation of the afferent components in one cardiopulmonary nerve (the left vagosympathetic complex at a level immediately caudal to the origin of the left recurrent laryngeal nerve) in acutely decentralized thoracic autonomic ganglionic preparations altered cardiac chronotropism and inotropism in 17 of 44 dogs. Since these neural preparations were acutely decentralized, the effects were mediated presumably via intrathoracic autonomic reflexes. The lack of consistency of these reflexly generated cardiac responses presumably were due in part to anatomical variation of afferent axons in the afferent nerve stimulated. As stimulation of the afferent components in the same neural structure caudal to the heart (where cardiopulmonary afferent axons are not present) failed to elicit cardiac responses in any dog, it is presumed that when cardiac responses were elicited by the more cranially located stimulations, these were due to activation of afferent axons arising from the heart and (or) lungs. When cardiac responses were elicited, intramyocardial pressures in the right ventricular conus as well as the ventral and lateral walls of the left ventricle were augmented. Either bradycardia or tachycardia was elicited. Following hexamethonium administration no responses were produced, demonstrating that nicotonic cholinergic synaptic mechanisms were involved in these intrathoracic cardiopulmonary-cardiac reflexes. In six of the animals, when atropine was administered before hexamethonium, reflexly generated responses were attenuated. The same thing occurred when morphine was administered in four animals. In contrast, in four animals following administration of phentolamine, the reflexly generated changes were enhanced.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of spinal metabotropic glutamate receptor 5 in pudendal inhibition of the nociceptive bladder reflex in cats.

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Reese, Jeremy N; Rogers, Marc J; Xiao, Zhiying; Shen, Bing; Wang, Jicheng; Schwen, Zeyad; Roppolo, James R; de Groat, William C; Tai, Changfeng

2015-04-15

This study examined the role of spinal metabotropic glutamate receptor 5 (mGluR5) in the nociceptive C-fiber afferent-mediated spinal bladder reflex and in the inhibtion of this reflex by pudendal nerve stimulation (PNS). In α-chloralose-anesthetized cats after spinal cord transection at the T9/T10 level, intravesical infusion of 0.25% acetic acid irritated the bladder, activated nociceptive C-fiber afferents, and induced spinal reflex bladder contractions of low amplitude (reflexes were responsible for a major component of the contractions. This study shows that spinal mGluR5 plays an important role in the nociceptive C-fiber afferent-mediated spinal bladder reflex and in pudendal inhibition of this spinal reflex. Copyright © 2015 the American Physiological Society.

ZAG-Otolith: Modification of Otolith-Ocular Reflexes, Motion Perception and Manual Control during Variable Radius Centrifugation Following Space Flight

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Wood, S. J.; Clarke, A. H.; Rupert, A. H.; Harm, D. L.; Clement, G. R.

2009-01-01

Two joint ESA-NASA studies are examining changes in otolith-ocular reflexes and motion perception following short duration space flights, and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. METHODS. Data is currently being collected on astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation is utilized to elicit otolith reflexes in the lateral plane without concordant roll canal cues. Unilateral centrifugation (400 deg/s, 3.5 cm radius) stimulates one otolith positioned off-axis while the opposite side is centered over the axis of rotation. During this paradigm, roll-tilt perception is measured using a subjective visual vertical task and ocular counter-rolling is obtained using binocular video-oculography. During a second paradigm (216 deg/s, otolith-mediated reflexes correspond to one's ability to perform closed-loop nulling tasks following G-transitions, and whether manual control performance can be improved with vibrotactile feedback of orientation.

Emotional Dissonance and Burnout: The Moderating Role of Team Reflexivity and Re-Evaluation.

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Andela, Marie; Truchot, Didier

2017-08-01

The aim of the present study was to better understand the relationship between emotional dissonance and burnout by exploring the buffering effects of re-evaluation and team reflexivity. The study was conducted with a sample of 445 nurses and healthcare assistants from a general hospital. Team reflexivity was evaluated with the validation of the French version of the team reflexivity scale (Facchin, Tschan, Gurtner, Cohen, & Dupuis, 2006). Burnout was measured with the MBI General Survey (Schaufeli, Leiter, Maslach, & Jackson, 1996). Emotional dissonance and re-evaluation were measured with the scale developed by Andela, Truchot, & Borteyrou (2015). With reference to Rimé's theoretical model (2009), we suggested that both dimensions of team reflexivity (task and social reflexivity) respond to both psychological necessities induced by dissonance (cognitive clarification and socio-affective necessities). Firstly, results indicated that emotional dissonance was related to burnout. Secondly, regression analysis confirmed the buffering role of re-evaluation and social reflexivity on the emotional exhaustion of emotional dissonance. Overall, results contribute to the literature by highlighting the moderating effect of re-evaluation and team reflexivity in analysing the relationship between emotional dissonance and burnout. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Are the unken reflex and the aposematic colouration of Red-Bellied Toads efficient against bird predation?

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Caorsi, Valentina Zaffaroni; Colombo, Patrick; Abadie, Michelle; Brack, Ismael Verrastro; Dasoler, Bibiana Terra; Borges-Martins, Márcio

2018-01-01

Aposematic signals as well as body behaviours may be important anti-predator defences. Species of the genus Melanophryniscus are characterised by having toxic lipophilic alkaloids in the skin and for presenting a red ventral colouration, which can be observed when they perform the behaviour called the unken reflex. Both the reflex behaviour and the colouration pattern are described as defence mechanisms. However, there are currently no studies testing their effectiveness against predators. This study aimed to test experimentally if both ventral conspicuous colouration and the unken reflex in Melanophryniscus cambaraensis function as aposematic signals against visually oriented predators (birds). We simulated the species studied using three different clay toad models as follows: (a) in a normal position with green coloured bodies, (b) in the unken reflex position with green coloured body and extremities and (c) in the unken reflex position with a green body and red extremities. Models were distributed on a known M. cambaraensis breeding site and in the adjacent forest. More than half of the attacks on the models were from birds; however, there was no preference for any model type. Thus, just the presence of the red colour associated with the motionless unken reflex position does not seem to prevent attacks from potential predators. It is possible that the effective aposematic signal in Melanophryniscus is achieved through the unken reflex movement together with the subsequent exhibition of the warning colouration and the secretion of toxins. PMID:29596437

The mechanism of sputter-induced orientation change in YBCO films on MgO (001)

International Nuclear Information System (INIS)

Huang, Y.; Vuchic, B.V.; Baldo, P.; Merkle, K.L.; Buchholz, D.B.; Mahajan, S.; Lei, J.S.; Markworth, P.R.; Chang, R.P.H.

1996-12-01

The mechanisms of the sputter-induced orientation change in YBa 2 Cu 3 O 7-x (YBCO) films grown on MgO (001) substrates by pulsed organometallic beam epitaxy (POMBE) are investigated by x-ray diffraction. Rutherford backscatter spectroscopy (RBS), cross-section TEM (XTEM) and microanalysis. It is found that the W atom implantation concurring with the ion sputtering plays an important role in effecting the orientation change. This implantation changes the surface structure of the substrate and induces an intermediate layer in the initial growth of the YBCO film, which in turn acts as a template that induces the orientation change. It seems that the surface morphology change caused by ion sputtering has only a minor effect on the orientation change

Modulation of defensive reflex conditioning in snails by serotonin

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Andrianov, Vyatcheslav V.; Bogodvid, Tatiana K.; Deryabina, Irina B.; Golovchenko, Aleksandra N.; Muranova, Lyudmila N.; Tagirova, Roza R.; Vinarskaya, Aliya K.; Gainutdinov, Khalil L.

2015-01-01

Highlights Daily injection of serotonin before a training session accelerated defensive reflex conditioning in snails.Daily injection of 5-hydroxytryptophan before a training session in snails with a deficiency of serotonin induced by the “neurotoxic” analog of serotonin 5,7-dihydroxytryptamine, restored the ability of snails to learn.After injection of the “neurotoxic” analogs of serotonin 5,6- and 5,7-dihydroxytryptamine as well as serotonin, depolarization of the membrane and decrease of the threshold potential of premotor interneurons was observed. We studied the role of serotonin in the mechanisms of learning in terrestrial snails. To produce a serotonin deficit, the “neurotoxic” analogs of serotonin, 5,6- or 5,7-dihydroxytryptamine (5,6/5,7-DHT) were used. Injection of 5,6/5,7-DHT was found to disrupt defensive reflex conditioning. Within 2 weeks of neurotoxin application, the ability to learn had recovered. Daily injection of serotonin before a training session accelerated defensive reflex conditioning and daily injections of 5-HTP in snails with a deficiency of serotonin induced by 5,7-DHT restored the snail's ability to learn. We discovered that injections of the neurotoxins 5,6/5,7-DHT as well as serotonin, caused a decrease in the resting and threshold potentials of the premotor interneurons LPa3 and RPa3. PMID:26557063

Reflex responses in the lower leg following landing impact on an inverting and non-inverting platform.

NARCIS (Netherlands)

Grüneberg, C.; Nieuwenhuijzen, P.H.J.A.; Duysens, J.E.J.

2003-01-01

In the lower leg, landing after a jump induces reflexes, the role of which is not well understood. This is even more so for reflexes following landing on inverting surfaces. The latter condition is of special interest since ankle inversion traumata are one of the most common injuries during sport.

[Reflex seizures, cinema and television].

Science.gov (United States)

Olivares-Romero, Jesús

2015-12-16

In movies and television series are few references to seizures or reflex epilepsy even though in real life are an important subgroup of total epileptic syndromes. It has performed a search on the topic, identified 25 films in which they appear reflex seizures. Most seizures observed are tonic-clonic and visual stimuli are the most numerous, corresponding all with flashing lights. The emotions are the main stimuli in higher level processes. In most cases it is not possible to know if a character suffers a reflex epilepsy or suffer reflex seizures in the context of another epileptic syndrome. The main conclusion is that, in the movies, the reflex seizures are merely a visual reinforcing and anecdotal element without significant influence on the plot.

Arakeri’s Reflex: an Alternative Pathway for Dento-Cardiac Reflex Mediated Syncope

Directory of Open Access Journals (Sweden)

Veena Arali

2010-03-01

Full Text Available Introduction: Dentocardiac reflex, a variant of trigeminocardiac reflex elicited specifically during tooth extraction procedures in den-tal/maxillofacial surgery and is believed to cause syncope with an afferent link mediated by posterior superior alveolar nerve. Another variant of trigeminocardiac reflex which is also of interest to the oral and maxillofacial surgeon is oculocardiac reflex which can be triggered by direct or indirect manipulation of eye globe or muscles around it.The hypothesis: Excessive or injudicious pressure or manipulations around the maxillary first molars during extraction procedure are as-sociated with maximum incidence of bradycardia and hypotension than around incisor/ canine/ third molars. This is because; the pressure on eye globe and ophthalmic rectus muscle is maximum during extraction of first molar than incisor/canine and third molars. This observation led us to postulate an alternative pathway for dentocardiac reflex mediated syncope which may possibly justify the maxillary first molar region as a prone factor for the trigger. Evaluation of the hypothesis: Present hypothesis may not confer the specific factor responsible for switch in autonomic response in syncope origin during the tooth extraction procedure, but may provide a clue to where we should be looking.

Towards Eco-reflexive Science Education. A Critical Reflection About Educational Implications of Green Chemistry

Science.gov (United States)

Sjöström, Jesper; Eilks, Ingo; Zuin, Vânia G.

2016-05-01

The modern world can be described as a globalized risk society. It is characterized by increasing complexity, unpredictable consequences of techno-scientific innovations and production, and its environmental consequences. Therefore, chemistry, just like many other knowledge areas, is in an ongoing process of environmentalization. For example, green chemistry has emerged as a new chemical metadiscipline and movement. The philosophy of green chemistry was originally based on a suggestion of twelve principles for environment-friendly chemistry research and production. The present article problematizes limitations in green chemistry when it comes to education. It argues that the philosophy of green chemistry in the context of education needs to be extended with socio-critical perspectives to form educated professionals and citizens who are able to understand the complexity of the world, to make value-based decisions, and to become able to engage more thoroughly in democratic decision-making on sustainability issues. Different versions of sustainability-oriented science/chemistry education are discussed to sharpen a focus on the most complex type, which is Bildung-oriented, focusing emancipation and leading to eco-reflexive education. The term eco- reflexive is used for a problematizing stance towards the modern risk society, an understanding of the complexity of life and society and their interactions, and a responsibility for individual and collective actions towards socio-ecojustice and global sustainability. The philosophical foundation and characteristics of eco-reflexive science education are sketched on in the article.

Oral 2-hydroxyoleic acid inhibits reflex hypersensitivity and open-field-induced anxiety after spared nerve injury.

Science.gov (United States)

Avila-Martin, G; Galan-Arriero, I; Ferrer-Donato, A; Busquets, X; Gomez-Soriano, J; Escribá, P V; Taylor, J

2015-01-01

Recently, fatty acids have been shown to modulate sensory function in animal models of neuropathic pain. In this study, the antinociceptive effect of 2-hydroxyoleic acid (2-OHOA) was assessed following spared nerve injury (SNI) with reflex and cerebrally mediated behavioural responses. Initial antinociceptive behavioural screening of daily administration of 2-OHOA (400 mg/kg, p.o.) was assessed in Wistar rats by measuring hindlimb reflex hypersensitivity to von Frey and thermal plate stimulation up to 7 days after SNI, while its modulatory effect on lumbar spinal dorsal horn microglia reactivity was assessed with OX-42 immunohistochemistry. In vitro the effect of 2-OHOA (120 μM) on cyclooxygenase protein expression (COX-2/COX-1 ratio) in lipopolysaccharide-activated macrophage cells was tested with Western blot analysis. Finally, the effects of 2-OHOA treatment on the place escape aversion paradigm (PEAP) and the open-field-induced anxiety test were tested at 21 days following nerve injury compared with vehicle-treated sham and pregabalin-SNI (30 mg/kg, p.o.) control groups. Oral 2-OHOA significantly reduced ipsilateral mechanical and thermal hypersensitivity up to 7 days after SNI. Additionally 2-OHOA decreased the COX-2/COX-1 ratio in lipopolysaccharide-activated macrophage cells and OX-42 expression within the ipsilateral lumbar spinal dorsal horn 7 days after SNI. 2-OHOA significantly restored inner-zone exploration in the open-field test compared with the vehicle-treated sham group at 21 days after SNI. Oral administration of the modified omega 9 fatty acid, 2-OHOA, mediates antinociception and prevents open-field-induced anxiety in the SNI model in Wistar rats, which is mediated by an inhibition of spinal dorsal horn microglia activation. © 2014 European Pain Federation - EFIC®

[H reflex in patients with spastic quadriplegia].

Science.gov (United States)

Miyama, Sahoko; Arimoto, Kiyoshi; Kimiya, Satoshi

2009-01-01

Hoffmann reflex (H reflex) is an electrically elicited spinal monosynaptic reflex. H reflex was examined in 18 patients with spastic quadriplegia who had perinatal or postnatal problems. H reflex was elicitable in 11 patients for the abductor pollicis brevis (61.1%), 10 for the abductor digiti minimi (55.6%) and 16 for the abductor hallucis (88.9%). Because the abductor pollicis brevis and the abductor digiti minimi do not exhibit H reflex in normal subjects, it was suggested that the excitability of alpha motor neurons innervating these muscles was increased. H reflex was not detected for the extensor digitorum brevis in any patients, indicating the difference in the excitability among alpha motor neurons. In some patients, H reflex did not disappear under supramaximal stimuli. We conclude that the mechanism of evolution of H reflex in patients with spastic quadriplegia is different from that in normal subjects.

Artificial-reflex stimulation for FES-induced standing with minimum quadriceps force

NARCIS (Netherlands)

Mulder, A.J.; Mulder, A.J.; Boom, H.B.K.; Hermens, Hermanus J.; Zilvold, G.; Zilvold, G.

1990-01-01

A control strategy is proposed to decrease quadriceps activity during standing. Modified on/off (or artificial reflex) control is used: a non-numerical or finite-state control scheme based on feedback of knee angle and angular velocity. The control strategy is evaluated in paraplegic patients in an

Time Course of the Soleus M Response and H Reflex after Lidocaine Tibial Nerve Block in the Rat

Directory of Open Access Journals (Sweden)

Kévin Buffenoir

2013-01-01

Full Text Available Aims. In spastic subjects, lidocaine is often used to induce a block predictive of the result provided by subsequent surgery. Lidocaine has been demonstrated to inhibit the Hoffmann (H reflex to a greater extent than the direct motor (M response induced by electrical stimulation, but the timecourse of these responses has not been investigated. Methods. An animal (rat model of the effects of lidocaine on M and H responses was therefore developed to assess this time course. M and H responses were recorded in 18 adult rats before and after application of lidocaine to the sciatic nerve. Results. Two to five minutes after lidocaine injection, M responses were markedly reduced (mean reduction of 44% and H reflexes were completely abolished. Changes were observed more rapidly for the H reflex. The effects of lidocaine then persisted for 100 minutes. The effect of lidocaine was therefore more prolonged on the H reflex than on the M response. Conclusion. This study confirms that lidocaine blocks not only alpha motoneurons but also Ia afferent fibres responsible for the H reflex. The authors describe, for the first time, the detailed time course of the effect of lidocaine on direct or reflex activation of motoneurons in the rat.

Fibril orientation redistribution induced by stretching of cellulose nanofibril hydrogels

International Nuclear Information System (INIS)

Josefsson, Gabriella; Gamstedt, E. Kristofer; Ahvenainen, Patrik; Mushi, Ngesa Ezekiel

2015-01-01

The mechanical performance of materials reinforced by cellulose nanofibrils is highly affected by the orientation of these fibrils. This paper investigates the nanofibril orientation distribution of films of partly oriented cellulose nanofibrils. Stripes of hydrogel films were subjected to different amount of strain and, after drying, examined with X-ray diffraction to obtain the orientation of the nanofibrils in the films, caused by the stretching. The cellulose nanofibrils had initially a random in-plane orientation in the hydrogel films and the strain was applied to the films before the nanofibrils bond tightly together, which occurs during drying. The stretching resulted in a reorientation of the nanofibrils in the films, with monotonically increasing orientation towards the load direction with increasing strain. Estimation of nanofibril reorientation by X-ray diffraction enables quantitative comparison of the stretch-induced orientation ability of different cellulose nanofibril systems. The reorientation of nanofibrils as a consequence of an applied strain is also predicted by a geometrical model of deformation of nanofibril hydrogels. Conversely, in high-strain cold-drawing of wet cellulose nanofibril materials, the enhanced orientation is promoted by slipping of the effectively stiff fibrils

Orientation Preferences and Motion Sickness Induced in a Virtual Reality Environment.

Science.gov (United States)

Chen, Wei; Chao, Jian-Gang; Zhang, Yan; Wang, Jin-Kun; Chen, Xue-Wen; Tan, Cheng

2017-10-01

Astronauts' orientation preferences tend to correlate with their susceptibility to space motion sickness (SMS). Orientation preferences appear universally, since variable sensory cue priorities are used between individuals. However, SMS susceptibility changes after proper training, while orientation preferences seem to be intrinsic proclivities. The present study was conducted to investigate whether orientation preferences change if susceptibility is reduced after repeated exposure to a virtual reality (VR) stimulus environment that induces SMS. A horizontal supine posture was chosen to create a sensory context similar to weightlessness, and two VR devices were used to produce a highly immersive virtual scene. Subjects were randomly allocated to an experimental group (trained through exposure to a provocative rotating virtual scene) and a control group (untrained). All subjects' orientation preferences were measured twice with the same interval, but the experimental group was trained three times during the interval, while the control group was not. Trained subjects were less susceptible to SMS, with symptom scores reduced by 40%. Compared with untrained subjects, trained subjects' orientation preferences were significantly different between pre- and posttraining assessments. Trained subjects depended less on visual cues, whereas few subjects demonstrated the opposite tendency. Results suggest that visual information may be inefficient and unreliable for body orientation and stabilization in a rotating visual scene, while reprioritizing preferences for different sensory cues was dynamic and asymmetric between individuals. The present findings should facilitate customization of efficient and proper training for astronauts with different sensory prioritization preferences and dynamic characteristics.Chen W, Chao J-G, Zhang Y, Wang J-K, Chen X-W, Tan C. Orientation preferences and motion sickness induced in a virtual reality environment. Aerosp Med Hum Perform. 2017

On Reflexive Data Models

Energy Technology Data Exchange (ETDEWEB)

Petrov, S.

2000-08-20

An information system is reflexive if it stores a description of its current structure in the body of stored information and is acting on the base of this information. A data model is reflexive, if its language is meta-closed and can be used to build such a system. The need for reflexive data models in new areas of information technology applications is argued. An attempt to express basic notions related to information systems is made in the case when the system supports and uses meta-closed representation of the data.

GABAergic mechanism mediated via D receptors in the rat periaqueductal gray participates in the micturition reflex: an in vivo microdialysis study.

Science.gov (United States)

Kitta, Takeya; Matsumoto, Machiko; Tanaka, Hiroshi; Mitsui, Takahiko; Yoshioka, Mitsuhiro; Nonomura, Katsuya

2008-06-01

The periaqueductal gray (PAG) is critically involved in the micturition reflex, but little is known about the neuronal mechanisms involved. The present study elucidated dynamic changes in dopamine (DA), glutamate and gamma-aminobutyric acid (GABA) in the rat PAG during the micturition reflex, with a focus on dopaminergic modulation using in vivo microdialysis combined with cystometrography. Extracellular levels of DA and glutamate increased, whereas levels of GABA decreased, in parallel with the micturition reflex. Application of a D(1) receptor antagonist into the PAG produced increases in maximal voiding pressure (MVP) and decreases in intercontraction interval (ICI), suggesting that the micturition reflex was facilitated by D(1) receptor blockade. The D(1) receptor antagonist prevented micturition-induced decreases in GABA efflux but had no effect on DA or glutamate. Neither a D(2) receptor antagonist nor a D(1)/D(2) receptor agonist affected these neurochemical and physiological parameters. Micturition-induced inhibition of GABA was not observed in 6-hydroxydopamine (6-OHDA)-lesioned rats, an animal model of Parkinson's disease. 6-OHDA-lesioned rats exhibited bladder hyperactivity evaluated by increases in MVP and decreases in ICI, mimicking facilitation of the micturition reflex induced by D(1) receptor blockade. These findings suggest that the micturition reflex is under tonic dopaminergic regulation through D(1) receptors, in which a GABAergic mechanism is involved. Bladder hyperactivity observed in 6-OHDA-lesioned rats may be caused by dysfunction of GABAergic regulation underlying the micturition reflex. The present findings contribute to our understanding not only of the neurophysiology of the micturition reflex but also of the pathophysiology of lower urinary tract dysfunction in patients with Parkinson's disease.

Effect of head pitch and roll orientations on magnetically induced vertigo.

Science.gov (United States)

Mian, Omar S; Li, Yan; Antunes, Andre; Glover, Paul M; Day, Brian L

2016-02-15

Lying supine in a strong magnetic field, such as in magnetic resonance imaging scanners, can induce a perception of whole-body rotation. The leading hypothesis to explain this invokes a Lorentz force mechanism acting on vestibular endolymph that acts to stimulate semicircular canals. The hypothesis predicts that the perception of whole-body rotation will depend on head orientation in the field. Results showed that the direction and magnitude of apparent whole-body rotation while stationary in a 7 T magnetic field is influenced by head orientation. The data are compatible with the Lorentz force hypothesis of magnetic vestibular stimulation and furthermore demonstrate the operation of a spatial transformation process from head-referenced vestibular signals to Earth-referenced body motion. High strength static magnetic fields are known to induce vertigo, believed to be via stimulation of the vestibular system. The leading hypothesis (Lorentz forces) predicts that the induced vertigo should depend on the orientation of the magnetic field relative to the head. In this study we examined the effect of static head pitch (-80 to +40 deg; 12 participants) and roll (-40 to +40 deg; 11 participants) on qualitative and quantitative aspects of vertigo experienced in the dark by healthy humans when exposed to the static uniform magnetic field inside a 7 T MRI scanner. Three participants were additionally examined at 180 deg pitch and roll orientations. The effect of roll orientation on horizontal and vertical nystagmus was also measured and was found to affect only the vertical component. Vertigo was most discomforting when head pitch was around 60 deg extension and was mildest when it was around 20 deg flexion. Quantitative analysis of vertigo focused on the induced perception of horizontal-plane rotation reported online with the aid of hand-held switches. Head orientation had effects on both the magnitude and the direction of this perceived rotation. The data suggest

The capsaicin cough reflex in patients with symptoms elicited by odorous chemicals

DEFF Research Database (Denmark)

Holst, H.; Arendt-Nielsen, Lars; Mosbech, H.

2010-01-01

between groups in age, body mass index or pulmonary function. The median C5 were 129 micromol/L (control group), 48 micromol/L (multiple chemical sensitivity patients), 32 micromol/L (eczema patients). The reporting of lower airway symptoms from odorous chemicals was significantly (p......Patients with multiple chemical sensitivity and eczema patients with airway symptoms elicited by odorous chemicals have enhanced cough reflex to capsaicin when applying the tidal breathing method. The aims of the present study were to test whether the capsaicin induced cough reflex was enhanced...... when applying the single breath inhalation method in similar groups of patients with symptoms related to odorous chemicals e.g. other persons wearing of perfume; and to investigate to what extent the reporting of lower airway symptoms influenced the cough reflex. Sixteen patients fulfilling Cullen...

Cough reflex sensitivity is increased in the guinea pig model of allergic rhinitis.

Science.gov (United States)

Brozmanova, M; Plevkova, J; Tatar, M; Kollarik, M

2008-12-01

Increased cough reflex sensitivity is found in patients with allergic rhinitis and may contribute to cough caused by rhinitis. We have reported that cough to citric acid is enhanced in the guinea pig model of allergic rhinitis. Here we address the hypothesis that the cough reflex sensitivity is increased in this model. The data from our previous studies were analyzed for the cough reflex sensitivity. The allergic inflammation in the nose was induced by repeated intranasal instillations of ovalbumin in the ovalbumin-sensitized guinea pigs. Cough was induced by inhalation of doubling concentrations of citric acid (0.05-1.6 M). Cough threshold was defined as the lowest concentration of citric acid causing two coughs (C2, expressed as geometric mean [95% confidence interval]). We found that the cough threshold was reduced in animals with allergic rhinitis. C2 was 0.5 M [0.36-0.71 M] and 0.15 M [0.1-0.23 M] prior and after repeated intranasal instillations of ovalbumin, respectively, Preflex sensitivity. C2 was reduced in animals with allergic rhinitis treated orally with vehicle (0.57 M [0.28-1.1] vs. 0.09 M [0.04-0.2 M], Preflex sensitivity is increased in the guinea pig model of allergic rhinitis. Our results suggest that guinea pig is a suitable model for mechanistic studies of increased cough reflex sensitivity in rhinitis.

Neurodevelopmental Reflex Testing in Neonatal Rat Pups.

Science.gov (United States)

Nguyen, Antoinette T; Armstrong, Edward A; Yager, Jerome Y

2017-04-24

Neurodevelopmental reflex testing is commonly used in clinical practice to assess the maturation of the nervous system. Neurodevelopmental reflexes are also referred to as primitive reflexes. They are sensitive and consistent with later outcomes. Abnormal reflexes are described as an absence, persistence, reappearance, or latency of reflexes, which are predictive indices of infants that are at high risk for neurodevelopmental disorders. Animal models of neurodevelopmental disabilities, such as cerebral palsy, often display aberrant developmental reflexes, as would be observed in human infants. The techniques described assess a variety of neurodevelopmental reflexes in neonatal rats. Neurodevelopmental reflex testing offers the investigator a testing method that is not otherwise available in such young animals. The methodology presented here aims to assist investigators in examining developmental milestones in neonatal rats as a method of detecting early-onset brain injury and/or determining the effectiveness of therapeutic interventions. The methodology presented here aims to provide a general guideline for investigators.

Reflex and Non-Reflex Torque Responses to Stretch of the Human Knee Extensors

National Research Council Canada - National Science Library

Mrachacz-Kersting, N

2001-01-01

.... The quadriceps muscles were stretched at various background torques, produced either voluntarily or electrically and thus the purely reflex-mediated torque could be calculated. The contribution of the reflex mediated stiffness initially low, increased with increasing background torques for the range of torques investigated.

Effect of spaceflight on the spatial orientation of the vestibulo-ocular reflex during eccentric roll rotation: A case report.

Science.gov (United States)

Reschke, Millard F; Wood, Scott J; Clément, Gilles

2018-01-01

Ground-based studies have reported shifts of the vestibulo-ocular reflex (VOR) slow phase velocity (SPV) axis toward the resultant gravito-inertial force vector. The VOR was examined during eccentric roll rotation before, during and after an 8-day orbital mission. On orbit this vector is aligned with the head z-axis. Our hypothesis was that eccentric roll rotation on orbit would generate horizontal eye movements. Two subjects were rotated in a semi-supine position with the head nasal-occipital axis parallel to the axis of rotation and 0.5 m off-center. The chair accelerated at 120 deg/s2 to 120 deg/s, rotated at constant velocity for one minute, and then decelerated to a stop in similar fashion. On Earth, the stimulation primarily generated torsional VOR. During spaceflight, in one subject torsional VOR became horizontal VOR, and then decayed very slowly. In the other subject, torsional VOR was reduced on orbit relative to pre- and post-flight, but the SPV axis did not rotate. We attribute the shift from torsional to horizontal VOR on orbit to a spatial orientation of velocity storage toward alignment with the gravito-inertial force vector, and the inter-individual difference to cognitive factors related to the subjective straight-ahead.

The capsaicin cough reflex in patients with symptoms elicited by odorous chemicals

DEFF Research Database (Denmark)

Holst, H; Arendt-Nielsen, L; Mosbech, H

2010-01-01

Patients with multiple chemical sensitivity and eczema patients with airway symptoms elicited by odorous chemicals have enhanced cough reflex to capsaicin when applying the tidal breathing method. The aims of the present study were to test whether the capsaicin induced cough reflex was enhanced...... when applying the single breath inhalation method in similar groups of patients with symptoms related to odorous chemicals e.g. other persons wearing of perfume; and to investigate to what extent the reporting of lower airway symptoms influenced the cough reflex. Sixteen patients fulfilling Cullen......'s criteria for multiple chemical sensitivity and 15 eczema patients with airway symptoms elicited by odorous chemicals were compared with 29 age-matched, healthy controls. We measured C5--the capsaicin concentration causing five coughs or more--using the single breath inhalation test. No difference was found...

Electroacupuncture modulation of reflex hypertension in rats: role of cholecystokinin octapeptide

Science.gov (United States)

Tjen-A-Looi, Stephanie C.; Guo, Zhi-Ling; Longhurst, John C.

2013-01-01

Acupuncture or electroacupuncture (EA) potentially offers a nonpharmacological approach to reduce high blood pressure (BP). However, ∼70% of the patients and animal subjects respond to EA, while 30% do not. EA acts, in part, through an opioid mechanism in the rostral ventrolateral medulla (rVLM) to inhibit sympathoexcitatory reflexes induced by gastric distention. CCK-8 opposes the action of opioids during analgesia. Therefore, we hypothesized that CCK-8 in the rVLM antagonizes EA modulation of sympathoexcitatory cardiovascular reflex responses. Male rats anesthetized with ketamine and α-chloralose subjected to repeated gastric distension every 10 min were examined for their responsiveness to EA (2 Hz, 0.5 ms, 1–4 mA) at P5-P6 acupoints overlying median nerve. Repeated gastric distension every 10 min evoked consistent sympathoexcitatory responses. EA at P5-P6 modulated gastric distension-induced responses. Microinjection of CCK-8 in the rVLM reversed the EA effect in seven responders. The CCK1 receptor antagonist devazepide microinjected into the rVLM converted six nonresponders to responders by lowering the reflex response from 21 ± 2.2 to 10 ± 2.9 mmHg (first vs. second application of EA). The EA modulatory action in rats converted to responders with devazepide was reversed with rVLM microinjection of naloxone (n = 6). Microinjection of devazepide in the absence of a second application of EA did not influence the primary pressor reflexes of nonresponders. These data suggest that CCK-8 antagonizes EA modulation of sympathoexcitatory cardiovascular responses through an opioid mechanism and that inhibition of CCK-8 can convert animals that initially are unresponsive to EA to become responsive. PMID:23785073

Repeated elicitation of the acoustic startle reflex leads to sensitisation in subsequent avoidance behaviour and induces fear conditioning

Directory of Open Access Journals (Sweden)

Janik Vincent M

2011-04-01

Full Text Available Abstract Background Autonomous reflexes enable animals to respond quickly to potential threats, prevent injury and mediate fight or flight responses. Intense acoustic stimuli with sudden onsets elicit a startle reflex while stimuli of similar intensity but with longer rise times only cause a cardiac defence response. In laboratory settings, habituation appears to affect all of these reflexes so that the response amplitude generally decreases with repeated exposure to the stimulus. The startle reflex has become a model system for the study of the neural basis of simple learning processes and emotional processing and is often used as a diagnostic tool in medical applications. However, previous studies did not allow animals to avoid the stimulus and the evolutionary function and long-term behavioural consequences of repeated startling remain speculative. In this study we investigate the follow-up behaviour associated with the startle reflex in wild-captured animals using an experimental setup that allows individuals to exhibit avoidance behaviour. Results We present evidence that repeated elicitation of the acoustic startle reflex leads to rapid and pronounced sensitisation of sustained spatial avoidance behaviour in grey seals (Halichoerus grypus. Animals developed rapid flight responses, left the exposure pool and showed clear signs of fear conditioning. Once sensitised, seals even avoided a known food source that was close to the sound source. In contrast, animals exposed to non-startling (long rise time stimuli of the same maximum sound pressure habituated and flight responses waned or were absent from the beginning. The startle threshold of grey seals expressed in units of sensation levels was comparable to thresholds reported for other mammals (93 dB. Conclusions Our results demonstrate that the acoustic startle reflex plays a crucial role in mediating flight responses and strongly influences the motivational state of an animal beyond a short

Acute Whole-Body Vibration does not Facilitate Peak Torque and Stretch Reflex in Healthy Adults

Directory of Open Access Journals (Sweden)

Ella W. Yeung

2013-03-01

Full Text Available The acute effect of whole-body vibration (WBV training may enhance muscular performance via neural potentiation of the stretch reflex. The purpose of this study was to investigate if acute WBV exposure affects the stretch induced knee jerk reflex [onset latency and electromechanical delay (EMD] and the isokinetic knee extensor peak torque performance. Twenty-two subjects were randomly assigned to the intervention or control group. The intervention group received WBV in a semi-squat position at 30° knee flexion with an amplitude of 0.69 mm, frequency of 45 Hz, and peak acceleration of 27.6 m/s2 for 3 minutes. The control group underwent the same semii-squatting position statically without exposure of WBV. Two-way mixed repeated measures analysis of variance revealed no significant group effects differences on reflex latency of rectus femoris (RF and vastus lateralis (VL; p = 0.934 and 0.935, respectively EMD of RF and VL (p = 0.474 and 0.551, respectively and peak torque production (p = 0.483 measured before and after the WBV. The results of this study indicate that a single session of WBV exposure has no potentiation effect on the stretch induced reflex and peak torque performance in healthy young adults.

The articulo-cardiac sympathetic reflex in spinalized, anesthetized rats.

Science.gov (United States)

Nakayama, Tomohiro; Suzuki, Atsuko; Ito, Ryuzo

2006-04-01

Somatic afferent regulation of heart rate by noxious knee joint stimulation has been proven in anesthetized cats to be a reflex response whose reflex center is in the brain and whose efferent arc is a cardiac sympathetic nerve. In the present study we examined whether articular stimulation could influence heart rate by this efferent sympathetic pathway in spinalized rats. In central nervous system (CNS)-intact rats, noxious articular movement of either the knee or elbow joint resulted in an increase in cardiac sympathetic nerve activity and heart rate. However, although in acutely spinalized rats a noxious movement of the elbow joint resulted in a significant increase in cardiac sympathetic nerve activity and heart rate, a noxious movement of the knee joint had no such effect and resulted in only a marginal increase in heart rate. Because this marginal increase was abolished by adrenalectomy suggests that it was due to the release of adrenal catecholamines. In conclusion, the spinal cord appears to be capable of mediating, by way of cardiac sympathetic nerves, the propriospinally induced reflex increase in heart rate that follows noxious stimulation of the elbow joint, but not the knee joint.

Charitable giving and reflexive individuals: How personal reflexivity mediates between structure and agency.

Science.gov (United States)

Sanghera, Balihar

2017-03-01

This article examines how individuals are reflexive beings who interpret the world in relation to things that matter to them, and how charitable acts are evaluated and embedded in their lives with different degrees of meaning and importance. Rather than framing the discussion of charitable practices in terms of an altruism/egoism binary or imputing motivations and values to social structures, the article explains how reflexivity is an important and neglected dimension of social practices, and how it interacts with sympathy, sentiments and discourses to shape giving. The study also shows that there are different modes of reflexivity, which have varied effects on charity and volunteering.

Central and peripheral mechanisms underlying gastric distention inhibitory reflex responses in hypercapnic-acidotic rats.

Science.gov (United States)

Tjen-A-Looi, Stephanie C; Hsiao, An-Fu; Longhurst, John C

2011-03-01

We have observed that in chloralose-anesthetized animals, gastric distension (GD) typically increases blood pressure (BP) under normoxic normocapnic conditions. However, we recently noted repeatable decreases in BP and heart rate (HR) in hypercapnic-acidotic rats in response to GD. The neural pathways, central processing, and autonomic effector mechanisms involved in this cardiovascular reflex response are unknown. We hypothesized that GD-induced decrease in BP and HR reflex responses are mediated during both withdrawal of sympathetic tone and increased parasympathetic activity, involving the rostral (rVLM) and caudal ventrolateral medulla (cVLM) and the nucleus ambiguus (NA). Rats anesthetized with ketamine and xylazine or α-chloralose were ventilated and monitored for HR and BP changes. The extent of cardiovascular inhibition was related to the extent of hypercapnia and acidosis. Repeated GD with both anesthetics induced consistent falls in BP and HR. The hemodynamic inhibitory response was reduced after blockade of the celiac ganglia or the intraabdominal vagal nerves with lidocaine, suggesting that the decreased BP and HR responses were mediated by both sympathetic and parasympathetic afferents. Blockade of the NA decreased the bradycardia response. Microinjection of kainic acid into the cVLM reduced the inhibitory BP response, whereas depolarization blockade of the rVLM decreased both BP and HR inhibitory responses. Blockade of GABA(A) receptors in the rVLM also reduced the BP and HR reflex responses. Atropine methyl bromide completely blocked the reflex bradycardia, and atenolol blocked the negative chronotropic response. Finally, α(1)-adrenergic blockade with prazosin reversed the depressor. Thus, in the setting of hypercapnic-acidosis, a sympathoinhibitory cardiovascular response is mediated, in part, by splanchnic nerves and is processed through the rVLM and cVLM. Additionally, a vagal excitatory reflex, which involves the NA, facilitates the GD-induced

[Laryngeal adduction reflex].

Science.gov (United States)

Ptok, M; Bonenberger, S; Miller, S; Kühn, D; Jungheim, M

2014-07-01

Laryngeal Adductor Reflex Background: A rapid closure of the vocal folds is necessary, whenever foreign materials or food particles penetrate into the larynx. Otherwise a passage of these particles into the trachea or the lower respiratory tract would be imminent. An aspiration could mechanically block the respiratory tract and cause severe dyspnoea or cause aspiration pneumonia. For this systematic review a selective literature research in PubMed and Scopus using the keywords "laryngeal adductor reflex" and "vocal fold closure" has been carried out. Apart from the oesophago-glottal and pharyngo-glottal closure reflexes, the laryngeal adductor reflex (LAR) has been investigated in particular. The LAR qualifies as a reflectory laryngeal adductor mechanism and involves early, presumably di- or oligosynaptic ipsilateral LAR1 as well as late polysynaptic ipsi- and contralateral LAR2 components. In clinical routine diagnostic settings of dysphagia, LAR is only assessed qualitatively and usually triggered by air pulses or tactile stimulation. Dysphagiologists often find that not only the laryngeal sensibility in general is impaired, but especially the protective laryngeal adduction mechanism, which results in a higher risk of aspiration. Thus, it appears mandatory to test the LAR not only qualitatively but also quantitatively. Unfortunately a valid and reliable method that can be employed in clinical practice has not yet been put forward. © Georg Thieme Verlag KG Stuttgart · New York.

Reflexive contraction of the levator palpebrae superioris muscle to involuntarily sustain the effective eyelid retraction through the transverse trigeminal proprioceptive nerve on the proximal Mueller's muscle: verification with evoked electromyography.

Science.gov (United States)

Ban, Ryokuya; Matsuo, Kiyoshi; Osada, Yoshiro; Ban, Midori; Yuzuriha, Shunsuke

2010-01-01

We have proposed a hypothetical mechanism to involuntarily sustain the effective eyelid retraction, which consists of not only voluntary but also reflexive contractions of the levator palpebrae superior muscle (LPSM). Voluntary contraction of fast-twitch fibres of the LPSM stretches the mechanoreceptors in Mueller's muscle to evoke trigeminal proprioception, which induces continuous reflexive contraction of slow-twitch fibres of the LPSM through the trigeminal proprioceptive nerve fibres innervating the mechanoreceptors in Mueller's muscle via the oculomotor neurons, as a tonic trigemino-oculomotor reflex. In the common skeletal mixed muscles, electrical stimulation of the proprioceptive nerve, which apparently connects the mechanoreceptors in muscle spindles to the motoneurons, induces the electromyographic response as the Hoffmann reflex. To verify the presence of the trigemino-oculomotor reflex, we confirmed whether intra-operative electrical simulation of the transverse trigeminal proprioceptive nerve on the proximal Mueller's muscle evokes an electromyographic response in the LPSM under general anaesthesia in 12 patients. An ipsilateral, phasic, short-latency response (latency: 2.8+/-0.3 ms) was induced in the ipsilateral LPSM in 10 of 12 subjects. As successful induction of the short-latency response in the ipsilateral LPSM corresponds to the Hoffmann reflex in the common skeletal mixed muscles, the present study is the first electromyographic verification of the presence of the monosynaptic trigemino-oculomotor reflex to induce reflexive contraction of the LPSM. The presence of the trigemino-oculomotor reflex may elucidate the unexplainable blepharoptosis due to surgery, trauma and tumour, all of which may damage the trigeminal proprioceptive nerve fibres to impair the trigemino-oculomotor reflex. Copyright (c) 2008. Published by Elsevier Ltd.

Differences in neurotransmitter systems of ventrolateral periaqueductal gray between the micturition reflex and nociceptive regulation: An in vivo microdialysis study.

Science.gov (United States)

Kitta, Takeya; Mitsui, Takahiko; Kanno, Yukiko; Chiba, Hiroki; Moriya, Kimihiko; Yoshioka, Mitsuhiro; Shinohara, Nobuo

2016-07-01

To elucidate the possible involvement of glutamate and serotonin (5-hydroxytryptamine) neurons in the ventrolateral midbrain periaqueductal gray during noxious stimulation. The study was carried out by evoking a noxious stimulation by acetic acid in an animal model of cystitis. Changes in glutamate and 5-hydroxytryptamine in the periaqueductal gray during the micturition reflex and acetic acid-induced cystitis were determined using in vivo microdialysis combined with cystometry in rats. Extracellular glutamate levels slightly, but significantly, increased during the micturition reflex induced by saline infusion into the bladder. Intravesical infusion of acetic acid facilitated the micturition reflex characterized by increases in voiding pressure and decreases in the intercontraction interval. Glutamate levels were markedly increased by acetic acid, and this enhancement was sustained for at least 3 h. 5-Hydroxytryptamine levels, which were not altered during the micturition reflex, were increased after intravesical infusion of acetic acid. The results suggest that periaqueductal gray glutamate and 5-hydroxytryptamine neurons differentially participate in the modulation of both nociception and the micturition reflex. Furthermore, periaqueductal gray 5-hydroxytryptamine levels appear to reflect the nociceptive stimuli. © 2016 The Japanese Urological Association.

Effect of chronic and acute cigarette smoking on the pharyngo-upper oesophageal sphincter contractile reflex and reflexive pharyngeal swallow

OpenAIRE

Dua, K; Bardan, E; Ren, J; Sui, Z; Shaker, R

1998-01-01

Background—Cigarette smoking is known to affect adversely the defence mechanisms against gastro-oesophageal reflux. The effect of smoking on the supraoesophageal reflexes that prevent aspiration of gastric contents has not been previously studied. 
Aims—To elucidate the effect of cigarette smoking on two of the supraoesophageal reflexes: the pharyngo-upper oesophageal sphincter (UOS) contractile reflex; and the reflexive pharyngeal swallow. 
Methods—Ten chronic smokers and 10 non-...

Leaders Learning Orientation and the HCM-turn in call centres

DEFF Research Database (Denmark)

Gnaur, Dorina

2013-01-01

as a significant leadership quality that promotes reflexivity in the ongoing processes of interpretation and meaning creation enhancing the human dimension in the production of service. Learning orientation will be related to high-commitment management (HCM) as a way to reconcile the logics of efficiency...

Electrical stimulation to the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle induces involuntary reflex contraction of the frontalis muscles.

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Matsuo, Kiyoshi; Osada, Yoshiro; Ban, Ryokuya

2013-02-01

The levator and frontalis muscles lack interior muscle spindles, despite consisting of slow-twitch fibres that involuntarily sustain eyelid-opening and eyebrow-raising against gravity. To compensate for this anatomical defect, this study hypothetically proposes that initial voluntary contraction of the levator fast-twitch muscle fibres stretches the mechanoreceptors in Müller's muscle and evokes proprioception, which continuously induces reflex contraction of slow-twitch fibres of the levator and frontalis muscles. This study sought to determine whether unilateral transcutaneous electrical stimulation to the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle could induce electromyographic responses in the frontalis muscles, with monitoring responses in the orbicularis oculi muscles. The study population included 27 normal subjects and 23 subjects with aponeurotic blepharoptosis, who displayed persistently raised eyebrows on primary gaze and light eyelid closure. The stimulation induced a short-latency response in the ipsilateral frontalis muscle of all subjects and long-latency responses in the bilateral frontalis muscles of normal subjects. However, it did not induce long-latency responses in the bilateral frontalis muscles of subjects with aponeurotic blepharoptosis. The orbicularis oculi muscles showed R1 and/or R2 responses. The stimulation might reach not only the proprioceptive fibres, but also other sensory fibres related to the blink or corneal reflex. The experimental system can provoke a monosynaptic short-latency response in the ipsilateral frontalis muscle, probably through the mesencephalic trigeminal proprioceptive neuron and the frontalis motor neuron, and polysynaptic long-latency responses in the bilateral frontalis muscles through an unknown pathway. The latter neural circuit appeared to be engaged by the circumstances of aponeurotic blepharoptosis.

Behavioral analysis of signals that guide learned changes in the amplitude and dynamics of the vestibulo-ocular reflex

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Raymond, J. L.; Lisberger, S. G.

1996-01-01

We characterized the dependence of motor learning in the monkey vestibulo-ocular reflex (VOR) on the duration, frequency, and relative timing of the visual and vestibular stimuli used to induce learning. The amplitude of the VOR was decreased or increased through training with paired head and visual stimulus motion in the same or opposite directions, respectively. For training stimuli that consisted of simultaneous pulses of head and target velocity 80-1000 msec in duration, brief stimuli caused small changes in the amplitude of the VOR, whereas long stimuli caused larger changes in amplitude as well as changes in the dynamics of the reflex. When the relative timing of the visual and vestibular stimuli was varied, brief image motion paired with the beginning of a longer vestibular stimulus caused changes in the amplitude of the reflex alone, but the same image motion paired with a later time in the vestibular stimulus caused changes in the dynamics as well as the amplitude of the VOR. For training stimuli that consisted of sinusoidal head and visual stimulus motion, low-frequency training stimuli induced frequency-selective changes in the VOR, as reported previously, whereas high-frequency training stimuli induced changes in the amplitude of the VOR that were more similar across test frequency. The results suggest that there are at least two distinguishable components of motor learning in the VOR. One component is induced by short-duration or high-frequency stimuli and involves changes in only the amplitude of the reflex. A second component is induced by long-duration or low-frequency stimuli and involves changes in the amplitude and dynamics of the VOR.

Magnetic anisotropy induced by crystallographic orientation and morphological alignment in directionally-solidified eutectic Mn-Sb alloy

Energy Technology Data Exchange (ETDEWEB)

Lou, Chang-Sheng [School of Materials Science and Engineering, Shenyang Ligong University, Shenyang 110159 (China); Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Liu, Tie, E-mail: liutie@epm.neu.edu.cn [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Dong, Meng; Wu, Chun; Shao, Jian-Guo; Wang, Qiang [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China)

2017-02-15

The influences of the crystallographic orientation and morphological alignment upon the magnetic anisotropic behavior of polycrystalline materials were investigated. Microstructures obtained in eutectic Mn-Sb alloys via directional solidification simultaneously displayed crystallographic orientation and morphological alignment. Both the crystallographic orientation and the morphological alignment were able to induce magnetic anisotropy in the alloys, wherein the influence of the crystallographic orientation and the morphological alignment upon the magnetic anisotropic behavior of the alloys strongly depended upon their directions and exhibited either mutual promotion or competition. These findings may provide useful guidance for the fabrication design of functional magnetic materials. - Highlights: • We study effects of orientation in crystal and morphology on magnetic anisotropy. • Both orientation in crystal and morphology can induce magnetic anisotropy. • Their effects depend on direction and exhibit either mutual promotion or competition.

"On Becoming a Critically Reflexive Practitioner" Redux: What Does It Mean to "Be" Reflexive?

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Cunliffe, Ann L.

2016-01-01

In this commentary, Cunliffe states that is convinced that reflexivity offers a way of foregrounding our moral and ethical responsibility for people and for the world around us. To "BE" reflexive was defined as embracing "subjective understandings of reality as a basis for thinking more critically about the impact of our…

Influence of impulsivity-reflexivity when testing dynamic spatial ability: sex and g differences.

Science.gov (United States)

Quiroga, M Angeles; Hernández, José Manuel; Rubio, Victor; Shih, Pei Chun; Santacreu, José

2007-11-01

This work analyzes the possibility that the differences in the performance of men and women in dynamic spatial tasks such as the Spatial Orientation Dynamic Test-Revised (SODT-R; Santacreu & Rubio, 1998), obtained in previous works, are due to cognitive style (Reflexivity-Impulsivity) or to the speed-accuracy tradeoff (SATO) that the participants implement. If these differences are due to cognitive style, they would be independent of intelligence, whereas if they are due to SATO, they may be associated with intelligence. In this work, 1652 participants, 984 men and 668 women, ages between 18 and 55 years, were assessed. In addition to the SODT-R, the "Test de Razonamiento Analitico, Secuencial e Inductivo" (TRASI [Analytical, Sequential, and Inductive Reasoning Test]; Rubio & Santacreu, 2003) was administered as a measure of general intelligence. Impulsivity scores (Zi) of Salkind and Wright (1977) were used to analyze reflexivity-impulsivity and SATO. The results obtained indicate that (a) four performance groups can be identified: Fast-accurate, Slow-inaccurate, Impulsive, and Reflexive. The first two groups solve the task as a function of a competence variable and the last two as a function of a personality variable; (b) performance differences should be attributed to SATO; (c) SATO differs depending on sex and intelligence level.

AMPUTATION AND REFLEX SYMPATHETIC DYSTROPHY

NARCIS (Netherlands)

GEERTZEN, JHB; EISMA, WH

Reflex sympathetic dystrophy is a chronic pain syndrome characterized by chronic burning pain, restricted range of motion, oedema and vasolability. Patients are difficult to treat and the prognosis is very often poor. This report emphasizes that an amputation in case of a reflex sympathetic

Portraying Reflexivity in Health Services Research.

Science.gov (United States)

Rae, John; Green, Bill

2016-09-01

A model is proposed for supporting reflexivity in qualitative health research, informed by arguments from Bourdieu and Finlay. Bourdieu refers to mastering the subjective relation to the object at three levels-the overall social space, the field of specialists, and the scholastic universe. The model overlays Bourdieu's levels of objectivation with Finlay's three stages of research (pre-research, data collection, and data analysis). The intersections of these two ways of considering reflexivity, displayed as cells of a matrix, pose questions and offer prompts to productively challenge health researchers' reflexivity. Portraiture is used to show how these challenges and prompts can facilitate such reflexivity, as illustrated in a research project. © The Author(s) 2016.

[Action-oriented versus state-oriented reactions to experimenter-induced failures].

Science.gov (United States)

Brunstein, J C

1989-01-01

The present study assessed different effects of action-oriented versus state-oriented styles of coping with failure on achievement-related performance and cognition. In a learned helplessness experiment, students were exposed to an academic failure situation and were then tested on a series of problem-solving tasks, either immediately after the pretreatment or after a delay of 24 hours. Performance and cognitive concomitants were measured during both experimental periods. Results demonstrated that action orientation was associated with self-immunizing cognitions during helplessness training. Action-oriented participants improved their performance level even after repeated failure feedbacks. Moreover, action-oriented students assigned to the delayed test condition responded with increased striving for success and showed performance increments, even in comparison with control subjects. In contrast, state-oriented participants developed symptoms of helplessness and showed impaired performance during failure inductions. In later tests on problem-solving tasks, state-oriented groups responded with increased fear of failure. Independent of immediate or delayed test conditions, they soon lapsed into new performance decrements.

Too Busy for Reflexivity?

DEFF Research Database (Denmark)

Ratner, Helene

What Danish school managers can teach STS researchers about epistemological ideals and pragmatic morals. Reflexivity has an ambivalent status in both anthropology and Science and Technology Studies. On the one hand, the critique of representation at the heart of the reflexivity debates of the 1980s...... highlighted non-symmetric relationships between observer and observed and accused the academic text of enacting a realist genre, concealing the relativism entailed in textual production (Clifford and Marcus 1986, Woolgar 1988, Ashmore 1989). On the other hand, the reflexivity program produced fears...... of a “corrosive relativism in which everything is but a more or less clever expression of opinion” (Geertz 1988:2, 3) and it has suffered the little flattering accusations of piling "layer upon layer of self-consciousness to no avail" (Latour 1988:170) with little “interest [for] … theoretically ambitious...

The passive of reflexive verbs in Icelandic

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Hlíf Árnadóttir

2011-10-01

Full Text Available The Reflexive Passive in Icelandic is reminiscent of the so-called New Passive (or New Impersonal in that the oblique case of a passivized object NP is preserved. As is shown by recent surveys, however, speakers who accept the Reflexive Passive do not necessarily accept the New Passive, whereas conversely, speakers who accept the New Passive do also accept the Reflexive Passive. Based on these results we suggest that there is a hierarchy in the acceptance of passive sentences in Icelandic, termed the Passive Acceptability Hierarchy. The validity of this hierarchy is confirmed by our diachronic corpus study of open access digital library texts from Icelandic journals and newspapers dating from the 19th and 20th centuries (tímarit.is. Finally, we sketch an analysis of the Reflexive Passive, proposing that the different acceptability rates of the Reflexive and New Passives lie in the argument status of the object. Simplex reflexive pronouns are semantically dependent on the verbs which select them, and should therefore be analyzed as syntactic arguments only, and not as semantic arguments of these verbs.

A reevaluation of the vestibulo-ocular reflex: new ideas of its purpose, properties, neural substrate, and disorders

Science.gov (United States)

Leigh, R. J.; Brandt, T.

1993-01-01

Conventional views of the vestibulo-ocular reflex (VOR) have emphasized testing with caloric stimuli and by passively rotating patients at low frequencies in a chair. The properties of the VOR tested under these conditions differ from the performance of this reflex during the natural function for which it evolved--locomotion. Only the VOR (and not visually mediated eye movements) can cope with the high-frequency angular and linear perturbations of the head that occur during locomotion; this is achieved by generating eye movements at short latency (disorders that disrupt the VOR cause not just only nystagmus, but also instability of posture (eg, increased fore-aft sway in patients with downbeat nystagmus) and disturbance of spatial orientation (eg, tilt of the subjective visual vertical in Wallenberg's syndrome).

The stretch reflex and the contributions of C David Marsden

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Kalyan B Bhattacharyya

2017-01-01

Full Text Available The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching by increasing its contractility as long as the stretch is within physiological limits. For ages, it was thought that the stretch reflex was of short latency and it was synonymous with the tendon reflex, subserving the same spinal reflex arc. However, disparities in the status of the two reflexes in certain clinical situations led Marsden and his collaborators to carry out a series of experiments that helped to establish that the two reflexes had different pathways. That the two reflexes are dissociated has been proved by the fact that the stretch reflex and the tendon reflex, elicited by stimulation of the same muscle, have different latencies, that of the stretch reflex being considerably longer. They hypothesized that the stretch reflex had a transcortical course before it reached the spinal motor neurons for final firing. Additionally, the phenomenon of stimulus-sensitive cortical myoclonus lent further evidence to the presence of the transcortical loop where the EEG correlate preceded the EMG discharge. This concept has been worked out by later neurologists in great detail , and the general consensus is that indeed, the stretch reflex is endowed with a conspicuous transcortical component.

Reno-Cerebral Reflex Activates the Renin-Angiotensin System, Promoting Oxidative Stress and Renal Damage After Ischemia-Reperfusion Injury.

Science.gov (United States)

Cao, Wei; Li, Aiqing; Li, Jiawen; Wu, Chunyi; Cui, Shuang; Zhou, Zhanmei; Liu, Youhua; Wilcox, Christopher S; Hou, Fan Fan

2017-09-01

A kidney-brain interaction has been described in acute kidney injury, but the mechanisms are uncertain. Since we recently described a reno-cerebral reflex, we tested the hypothesis that renal ischemia-reperfusion injury (IRI) activates a sympathetic reflex that interlinks the renal and cerebral renin-angiotensin axis to promote oxidative stress and progression of the injury. Bilateral ischemia-reperfusion activated the intrarenal and cerebral, but not the circulating, renin-angiotensin system (RAS), increased sympathetic activity in the kidney and the cerebral sympathetic regulatory regions, and induced brain inflammation and kidney injury. Selective renal afferent denervation with capsaicin or renal denervation significantly attenuated IRI-induced activation of central RAS and brain inflammation. Central blockade of RAS or oxidative stress by intracerebroventricular (ICV) losartan or tempol reduced the renal ischemic injury score by 65% or 58%, respectively, and selective renal afferent denervation or reduction of sympathetic tone by ICV clonidine decreased the score by 42% or 52%, respectively (all p renal damage and dysfunction persisted after controlling blood pressure with hydralazine. This study uncovered a novel reflex pathway between ischemic kidney and the brain that sustains renal oxidative stress and local RAS activation to promote ongoing renal damage. These data suggest that the renal and cerebral renin-angiotensin axes are interlinked by a reno-cerebral sympathetic reflex that is activated by ischemia-reperfusion, which contributes to ischemia-reperfusion-induced brain inflammation and worsening of the acute renal injury. Antioxid. Redox Signal. 27, 415-432.

Vasovagal oscillations and vasovagal responses produced by the Vestibulo-Sympathetic Reflex in the rat

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Sergei B. Yakushin

2014-04-01

Full Text Available Sinusoidal galvanic vestibular stimulation (sGVS induces oscillations in blood pressure (BP and heart rate (HR i.e., vasovagal oscillations, and decreases in BP and HR i.e., vasovagal responses, in isoflurane-anesthetized rats. We determined the characteristics of the vasovagal oscillations, assessed their role in the generation of vasovagal responses and determined whether they could be induced by monaural as well as by binaural sGVS and by oscillation in pitch. Wavelet analyses were used to determine the power distributions of the waveforms. Monaural and binaural sGVS and pitch generated vasovagal oscillations at the frequency and at twice the frequency of stimulation. Vasovagal oscillations and vasovagal responses were maximally induced at low stimulus frequencies (0.025-0.05 Hz. The oscillations were attenuated and the responses were rarely induced at higher stimulus frequencies. Vasovagal oscillations could occur without induction of vasovagal responses, but vasovagal responses were always associated with a vasovagal oscillation. We posit that the vasovagal oscillations originate in a low frequency band that, when appropriately activated by strong sympathetic stimulation, can generate vasovagal oscillations as a precursor for vasovagal responses and syncope. We further suggest that the activity responsible for the vasovagal oscillations arises in low frequency, otolith neurons with orientation vectors close to the vertical axis of the head. These neurons are likely to provide critical input to the Vestibulo-Sympathetic Reflex to increase BP and HR upon changes in head position relative to gravity, and to contribute to the production of vasovagal oscillations and vasovagal responses and syncope when the baroreflex is inactivated.

O conceito de reflexão de Hegel como crítica aos conceitos de essência e de reflexão tradicionais

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Christian Iber

2017-02-01

Full Text Available O presente artigo ilumina o específico do conceito de reflexão de Hegel em cinco momentos. Em um primeiro momento, delineia-se um esboço do conceito de reflexão na lógica da essência de Hegel. Em um segundo momento, o conceito de reflexão de Hegel é apresentado como estrutura lógica objetiva em contraste com a reflexão subjetiva da consciência e do entendimento, com a qual, ao mesmo tempo, o conceito de essência ontológica independente da reflexão é submetido a uma crítica. Do novo conceito de reflexão de Hegel resulta, em terceiro lugar, uma adaptação radical do círculo vicioso na teoria tradicional da reflexão da autoconsciência. Num quarto momento, lança-se um olhar sobre o conceito de reflexão anterior de Hegel como pensar do entendimento que separa, do qual o conceito de reflexão posterior se distingue. Por fim, apresenta-se, em quinto lugar, a lógica da reflexão de Hegel como crítica à fundação ontológica da reflexão em Schelling. O conceito de reflexão de Hegel se mostra, com isto, como crítica da metafísica ontológica tradicional e como fundação de uma metafísica da relacionalidade absoluta que supera a relatividade do pensar moderno do entendimento.

Relationship between vomiting reflex during esophagogastroduodenoscopy and dyspepsia symptoms.

Science.gov (United States)

Enomoto, Shotaro; Watanabe, Mika; Yoshida, Takeichi; Mukoubayashi, Chizu; Moribata, Kosaku; Muraki, Yosuke; Shingaki, Naoki; Deguchi, Hisanobu; Ueda, Kazuki; Inoue, Izumi; Maekita, Takao; Iguchi, Mikitaka; Tamai, Hideyuki; Kato, Jun; Fujishiro, Mitsuhiro; Oka, Masashi; Mohara, Osamu; Ichinose, Masao

2012-09-01

Although frequent vomiting reflexes during esophagogastroduodenoscopy (EGD) causes suffering in patients, very few studies have investigated the characteristics of subjects who frequently develop vomiting reflexes. This study examined the incidence of the vomiting reflex and related factors, especially upper gastrointestinal symptoms, among individuals undergoing transoral EGD. Subjects included 488 consecutive adults (mean age, 56.1 ± 8.9 years) who underwent transoral EGD for gastric cancer screening between February 2010 and March 2011. All procedures were performed by an endoscopist with 15 years of experience. Based on a questionnaire survey using the frequency scale for the symptoms of gastroesophageal reflux disease (FSSG), symptoms (dyspepsia and acid reflux symptoms) and the number of vomiting reflexes during EGD were recorded. Of the 488 subjects, 271 (56%) developed vomiting reflexes (mean, 4.2 times). This reflex-positive group was younger (54.3 ± 9.5 years) than the reflex-negative group (58.3 ± 7.7 years, P reflex-positive group with a high FSSG dyspepsia score (2.27 ± 2.57 vs 1.23 ± 1.84; P acid reflux symptom score (1.96 ± 2.22 vs 1.34 ± 2.14; P reflex-negative group. Multivariate analysis also showed a significant correlation between these four factors and the occurrence of vomiting reflexes. Using an FSSG dyspepsia score of 1 as the cut-off offered 68% sensitivity and 57% specificity for predicting the occurrence of vomiting reflexes. Based on FSSG questionnaire responses on upper gastrointestinal symptoms, dyspepsia symptoms, in particular, are related to presence of vomiting reflexes during EGD. © 2012 The Authors. Digestive Endoscopy © 2012 Japan Gastroenterological Endoscopy Society.

Dynamic clinical measurements of voluntary vaginal contractions and autonomic vaginal reflexes.

Science.gov (United States)

Broens, Paul M A; Spoelstra, Symen K; Weijmar Schultz, Willibrord C M

2014-12-01

The vaginal canal is an active and responsive canal. It has pressure variations along its length and shows reflex activity. At present, the prevailing idea is that the vaginal canal does not have a sphincter mechanism. It is hypothesized that an active vaginal muscular mechanism exists and might be involved in the pathophysiology of genito-pelvic pain/penetration disorder. The aim of this study was to detect the presence of a canalicular vaginal "sphincter mechanism" by measuring intravaginal pressure at different levels of the vaginal canal during voluntary pelvic floor contractions and during induced reflexive contractions. Sixteen nulliparous women, without sexual dysfunction and pelvic floor trauma, were included in the study. High-resolution solid-state circumferential catheters were used to measure intravaginal pressures and vaginal contractions at different levels in the vaginal canal. Voluntary intravaginal pressure measurements were performed in the left lateral recumbent position only, while reflexive intravaginal pressure measurements during slow inflation of a vaginal balloon were performed in the left lateral recumbent position and in the sitting position. Intravaginal pressures and vaginal contractions were the main outcome measures. In addition, a general demographic and medical history questionnaire was administered to gain insight into the characteristics of the study population. Fifteen out of the sixteen women had deep and superficial vaginal high-pressure zones. In one woman, no superficial high-pressure zone was found. The basal and maximum pressures, as well as the duration of the autonomic reflexive contractions significantly exceeded the pressures and the duration of the voluntary contractions. There were no significant differences between the reflexive measurements obtained in the left lateral recumbent and the sitting position. The two high-pressure zones found in this study, as a result of voluntary contractions and, even more pronounced

A near catastrophe from trigeminocardiac reflex

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Parmod K Bithal

2017-01-01

Full Text Available Trigeminocardiac reflex is a brainstem reflex that results from stimulation of any branch of the trigeminal nerve along its course. It produces a constellation of signs and symptoms decrease in blood pressure (BP and heart rate, dysrhythmias, apnoea and increased gastric motility. We present a case of 80-year-old female patient who developed alarming hypotension and bradycardia during craniotomy for meningioma excision resulting from this reflex. In the face of refractory hypotension despite administering ephedrine and phenylephrine, we had to resort to adrenaline to restore her normal BP.

Acute effects of high-frequency microfocal vibratory stimulation on the H reflex of the soleus muscle. A double-blind study in healthy subjects.

Science.gov (United States)

Alfonsi, Enrico; Paone, Paolo; Tassorelli, Cristina; De Icco, Roberto; Moglia, Arrigo; Alvisi, Elena; Marchetta, Lucky; Fresia, Mauro; Montini, Alessandra; Calabrese, Marzia; Versiglia, Vittorio; Sandrini, Giorgio

2015-01-01

This study in healthy subjects examined the effects of a system delivering focal microvibrations at high frequency (Equistasi®) on tonic vibration stimulus (TVS)-induced inhibition of the soleus muscle H reflex. Highfrequency microvibrations significantly increased the inhibitory effect of TVS on the H reflex for up to three minutes. Moreover, Equistasi® also significantly reduced alpha-motoneuron excitability, as indicated by the changes in the ratio between the maximumamplitude H reflex (Hmax reflex) and the maximumamplitude muscle response (Mmax response); this effect was due to reduction of the amplitude of the H reflex because the amplitude of muscle response remained unchanged. The present findings indicate that Equistasi® has a modulatory effect on proprioceptive reflex circuits. Therefore, Equistasi® might interfere with some mechanisms involved in both physiological and pathophysiological control of movement and of posture.

Consumers' purchase of organic food products. A matter of convenience and reflexive practices.

Science.gov (United States)

Hjelmar, Ulf

2011-04-01

The aim of this study was to gain insight into the purchase of organic food products by consumers and to explore the main factors driving this process. This paper uses evidence from 16 in-depth interviews with consumers in Denmark carried out in 2008-2009. On the basis of the analysis two broad concepts are suggested: convenience behaviours and reflexive practices. Convenience behaviours are characteristic of pragmatic organic consumers. This type of shopping behaviour requires organic foods to be available in the local supermarket, they have to be clearly visible (preferably with an eco-label), and the price differential vis-à-vis conventional products have to be minimal. The analysis also showed that politically/ethically minded consumers have reflexive practices when purchasing organic food products: health considerations, ethical considerations (animal welfare), political considerations (environmentalism) and quality considerations (taste) play an important part for these consumers. Reflexive shopping practices can be sparked by life events (e.g. having children), "shocking" news about conventional food products and similar events, and news capable of creating a "cognitive dissonance" among consumers. The Danish case illustrates that the government needs to actively implement reforms and promote activities which make organic products a convenient choice for the pragmatic oriented consumer if their market share is to increase substantially. Copyright © 2011 Elsevier Ltd. All rights reserved.

Problem-oriented project studies

DEFF Research Database (Denmark)

Nielsen, Jørgen Lerche; Danielsen, Oluf

2010-01-01

and marking papers / essays is complemented and in some way overruled by a new role as supervisor and facilitator for the group of students working with a research problem, they themselves have picked. However different dimensions of this new teacher role can be seen – from expert in an academic field (result......-oriented focusing on how the final product demonstrates the students’ ‘correct’ way to handle the academic aspects of the subject in mind) to a role more focusing on processes, methodological dimensions and stressing the importance of a reflexive approach. Some teachers may even tend to take on a role...

Wh-filler-gap dependency formation guides reflexive antecedent search

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Michael eFrazier

2015-10-01

Full Text Available Prior studies on online sentence processing have shown that the parser can resolve non-local dependencies rapidly and accurately. This study investigates the interaction between the processing of two such non-local dependencies: wh-filler-gap dependencies (WhFGD and reflexive-antecedent dependencies. We show that reflexive-antecedent dependency resolution is sensitive to the presence of a WhFGD, and argue that the filler-gap dependency established by WhFGD resolution is selected online as the antecedent of a reflexive dependency. We investigate the processing of constructions like (1, where two NPs might be possible antecedents for the reflexive, namely which cowgirl and Mary. Even though Mary is linearly closer to the reflexive, the only grammatically licit antecedent for the reflexive is the more distant wh-NP, which cowgirl. 1. Which cowgirl did Mary expect to have injured herself due to negligence?Four eye-tracking text-reading experiments were conducted on examples like (1, differing in whether the embedded clause was non-finite (1 and 3 or finite (2 and 4, and in whether the tail of the wh-dependency intervened between the reflexive and its closest overt antecedent (1 and 2 or the wh-dependency was associated with a position earlier in the sentence (3 and 4.The results of Experiments 1 and 2 indicate the parser accesses the result of WhFGD formation during reflexive antecedent search. The resolution of a wh-dependency alters the representation that reflexive antecedent search operates over, allowing the grammatical but linearly distant antecedent to be accessed rapidly. In the absence of a long-distance WhFGD (Exp. 3 and 4, wh-NPs were not found to impact reading times of the reflexive, indicating that the parser's ability to select distant wh-NPs as reflexive antecedents crucially involves syntactic structure.

Reflexivity and social justice

DEFF Research Database (Denmark)

Maksimovic, Tijana; Jakobsen, Helle Nordentoft

2017-01-01

Career practitioners’ reflexive understanding of their professional role as change agents in career guidance and counselling practices has a major impact on how social justice can be achieved. This entitles an awareness of the way in which guidance and counselling practices are embedded in the co......Career practitioners’ reflexive understanding of their professional role as change agents in career guidance and counselling practices has a major impact on how social justice can be achieved. This entitles an awareness of the way in which guidance and counselling practices are embedded...

Long-term depression-like plasticity of the blink reflex for the treatment of blepharospasm.

Science.gov (United States)

Kranz, Gottfried; Shamim, Ejaz A; Lin, Peter T; Kranz, George S; Hallett, Mark

2013-04-01

Our previous work showed a beneficial therapeutic effect on blepharospasm using slow repetitive transcranial magnetic stimulation, which produces a long-term depression (LTD)-like effect. High-frequency supraorbital electrical stimulation, asynchronous with the R2 component of the blink reflex, can also induce LTD-like effects on the blink reflex circuit in healthy subjects. Patients with blepharospasm have reduced inhibition of their blink recovery curves; therefore, a LTD-like intervention might normalize the blink reflex recovery (BRR) and have a favorable therapeutic effect. This is a randomized, sham-controlled, observer-blinded prospective study. In 14 blepharospasm patients, we evaluated the effects of high-frequency supraorbital stimulation on three separate treatment days. We applied 28 trains of nine stimuli, 400 Hz, either before or after the R2 or used sham stimulation. The primary outcome was the blink rate, number of spasms rated by a blinded physician and patient rating before, immediately after and 1 hour after stimulation while resting, reading, and talking; secondary outcome was the BRR. Stimulation "before" and "after" the R2 both showed a similar improvement as sham stimulation in physician rating, but patients felt significantly better with the before condition. Improvement in recovery of the blink reflex was noted only in the before condition. Clinical symptoms differed in the three baseline conditions (resting, reading, and talking). Stimulation before R2 increased inhibition in trigeminal blink reflex circuits in blepharospasm toward normal values and produced subjective, but not objective, improvement. Inhibition of the blink reflex pathway by itself appeared to be insufficient for a useful therapeutic effect. Copyright © 2013 Movement Disorder Society.

Virtues in participatory design: cooperation, curiosity, creativity, empowerment and reflexivity.

Science.gov (United States)

Steen, Marc

2013-09-01

In this essay several virtues are discussed that are needed in people who work in participatory design (PD). The term PD is used here to refer specifically to an approach in designing information systems with its roots in Scandinavia in the 1970s and 1980s. Through the lens of virtue ethics and based on key texts in PD, the virtues of cooperation, curiosity, creativity, empowerment and reflexivity are discussed. Cooperation helps people in PD projects to engage in cooperative curiosity and cooperative creativity. Curiosity helps them to empathize with others and their experiences, and to engage in joint learning. Creativity helps them to envision, try out and materialize ideas, and to jointly create new products and services. Empowerment helps them to share power and to enable other people to flourish. Moreover, reflexivity helps them to perceive and to modify their own thoughts, feelings and actions. In the spirit of virtue ethics-which focuses on specific people in concrete situations-several examples from one PD project are provided. Virtue ethics is likely to appeal to people in PD projects because it is practice-oriented, provides room for exploration and experimentation, and promotes professional and personal development. In closing, some ideas for practical application, for education and for further research are discussed.

Suppression of the cough reflex by α2-adrenergic receptor agonists in the rabbit

Science.gov (United States)

Cinelli, Elenia; Bongianni, Fulvia; Pantaleo, Tito; Mutolo, Donatella

2013-01-01

The α2-adrenergic receptor agonist clonidine has been shown to inhibit citric acid-induced cough responses in guinea pigs when administered by aerosol, but not orally. In contrast, oral or inhaled clonidine had no effect on capsaicin-induced cough and reflex bronchoconstriction in humans. In addition, intravenous administration of clonidine has been shown to depress fentanyl-induced cough in humans. We investigated the effects of the α2-adrenergic receptor agonists, clonidine and tizanidine, on cough responses induced by mechanical and chemical (citric acid) stimulation of the tracheobronchial tree. Drugs were microinjected (30–50 nL) into the caudal nucleus tractus solitarii (cNTS) and the caudal ventral respiratory group (cVRG) as well as administered intravenously in pentobarbital sodium-anesthetized, spontaneously breathing rabbits. Bilateral microinjections of clonidine into the cNTS or the cVRG reduced cough responses at 0.5 mmol/L and abolished the cough reflex at 5 mmol/L. Bilateral microinjections of 0.5 mmol/L tizanidine into the cNTS completely suppressed cough responses, whereas bilateral microinjections of 5 mmol/L into the cVRG only caused mild reductions in them. Depressant effects on the cough reflex of clonidine and tizanidine were completely reverted by microinjections of 10 mmol/L yohimbine. Intravenous administration of clonidine (80–120 μg/kg) or tizanidine (150–300 μg/kg) strongly reduced or completely suppressed cough responses. These effects were reverted by intravenous administration of yohimbine (300 μg/kg). The results demonstrate that activation of α2-adrenergic receptors in the rabbit exerts potent inhibitory effects on the central mechanism generating the cough motor pattern with a clear action at the level of the cNTS and the cVRG. PMID:24400133

Rapid motor learning in the translational vestibulo-ocular reflex

Science.gov (United States)

Zhou, Wu; Weldon, Patrick; Tang, Bingfeng; King, W. M.; Shelhamer, M. J. (Principal Investigator)

2003-01-01

Motor learning was induced in the translational vestibulo-ocular reflex (TVOR) when monkeys were repeatedly subjected to a brief (0.5 sec) head translation while they tried to maintain binocular fixation on a visual target for juice rewards. If the target was world-fixed, the initial eye speed of the TVOR gradually increased; if the target was head-fixed, the initial eye speed of the TVOR gradually decreased. The rate of learning acquisition was very rapid, with a time constant of approximately 100 trials, which was equivalent to or=1 d without any reinforcement, indicating induction of long-term synaptic plasticity. Although the learning generalized to targets with different viewing distances and to head translations with different accelerations, it was highly specific for the particular combination of head motion and evoked eye movement associated with the training. For example, it was specific to the modality of the stimulus (translation vs rotation) and the direction of the evoked eye movement in the training. Furthermore, when one eye was aligned with the heading direction so that it remained motionless during training, learning was not expressed in this eye, but only in the other nonaligned eye. These specificities show that the learning sites are neither in the sensory nor the motor limb of the reflex but in the sensory-motor transformation stage of the reflex. The dependence of the learning on both head motion and evoked eye movement suggests that Hebbian learning may be one of the underlying cellular mechanisms.

O conceito de reflexão de Hegel como crítica aos conceitos de essência e de reflexão tradicionais

OpenAIRE

Christian Iber

2017-01-01

O presente artigo ilumina o específico do conceito de reflexão de Hegel em cinco momentos. Em um primeiro momento, delineia-se um esboço do conceito de reflexão na lógica da essência de Hegel. Em um segundo momento, o conceito de reflexão de Hegel é apresentado como estrutura lógica objetiva em contraste com a reflexão subjetiva da consciência e do entendimento, com a qual, ao mesmo tempo, o conceito de essência ontológica independente da reflexão é submetido a uma crítica. Do novo conceito d...

Highly -oriented growth of polycrystalline silicon films on glass by pulsed magnetron sputtering

International Nuclear Information System (INIS)

Reinig, P.; Selle, B.; Fenske, F.; Fuhs, W.; Alex, V.; Birkholz, M.

2002-01-01

Nominally undoped polycrystalline silicon (poly-Si) thin films were deposited on glass at 450 deg. C at high deposition rate (>100 nm/min) by pulsed dc magnetron sputtering. The pulse frequency was found to have a significant influence on the preferred grain orientation. The x-ray diffraction pattern exhibits a strong enhancement of the (400) reflex with increasing pulse frequency. The quantitative evaluation reveals that over 90% of the grains are oriented. The observed change in preferred grain orientation in poly-Si films at low temperatures is associated with concurrent ion bombardment of the growing film

Effect of betel nut chewing on the otolithic reflex system.

Science.gov (United States)

Lin, Chuan-Yi; Young, Yi-Ho

2017-01-01

This study investigated the effect of betel nut chewing on the otolithic reflex system. Seventeen healthy volunteers without any experience of chewing betel nut (fresh chewers) and 17 habitual chewers underwent vital sign measurements, ocular vestibular-evoked myogenic potential (oVEMP), and cervical VEMP (cVEMP) tests prior to the study. Each subject then chewed two pieces of betel nut for 2min (dosing). The same paradigm was repeated immediately, 10min, and 20min after chewing. On a different day, 10 fresh chewers masticated chewing gum as control. Fresh chewers exhibited significantly decreased response rates of oVEMP (53%) and cVEMP (71%) after dosing compared with those from the predosing period. These abnormal VEMPs returned to normal 20min after dosing. In contrast, 100% response rates of oVEMP and cVEMP were observed before and after masticating chewing gum. In habitual chewers, the response rates of oVEMP and cVEMP were 32% and 29%, respectively, 20min after dosing. Chewing betel nuts induced a transient loss of the otolithic reflexes in fresh chewers but may cause permanent loss in habitual chewers. Chewing betel nuts can cause a loss of otholitic reflex function. This creates a risk for disturbed balance and malfunction, for instance, during driving. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Backward-walking biological motion orients attention to moving away instead of moving toward.

Science.gov (United States)

Ding, Xiaowei; Yin, Jun; Shui, Rende; Zhou, Jifan; Shen, Mowei

2017-04-01

Walking direction is an important attribute of biological motion because it carries key information, such as the specific intention of the walker. Although it is known that spatial attention is guided by walking direction, it remains unclear whether this attentional shift is reflexive (i.e., constantly shifts to the walking direction) or not. A richer interpretation of this effect is that attention is guided to seek the information that is necessary to understand the motion. To investigate this issue, we examined how backward-walking biological motion orients attention because the intention of walking backward is usually to avoid something that walking forward would encounter. The results showed that attention was oriented to the walking-away direction of biological motion instead of the walking-toward direction (Experiment 1), and this effect was not due to the gaze direction of biological motion (Experiment 2). Our findings suggest that the attentional shift triggered by walking direction is not reflexive, thus providing support for the rich interpretation of these attentional effects.

[Effects of morphine on pupillary light reflex in monkeys].

Science.gov (United States)

Meng, Zhi-Qiang; Zhang, Yu-Hua; Chen, Nan-Hui; Miao, Ying-Da; Hu, Xin-Tian; Ma, Yuan-Ye

2010-06-01

The pupil size of both human and other animals can be affected by light. Many kinds of psychiatrical and psychological disorders, such as drug abuse, associate with abnormal properties of pupillary light reflex. Thus, the properties of pupillary light reflex could serve as an indicator for drug abuse detection. However, the effect of drug abuse on pupillary light reflex is till unclear. To assess the effects of addictive drugs on pupillary light reflex quantificationally, in the present study, we examined the effects of morphine on pupil diameter and pupillary light reflex in rhesus monkeys. By measuring the pupil diameter at different timing points before and after the administration of morphine, we found that morphine administration reduced the diameter of pupil and decreased the constriction rate. Our present results provide an experimental support for applying the properties of pupillary light reflex as a reference in addicts' detection.

Comparison of Two Methods for Inducing Reflex Cough in Patients With Parkinson's Disease, With and Without Dysphagia.

Science.gov (United States)

Hegland, Karen W; Troche, Michelle S; Brandimore, Alexandra; Okun, Michael S; Davenport, Paul W

2016-02-01

Aspiration pneumonia is a common cause of death in people with Parkinson's disease (PD). Dysfunctional swallowing occurs in the majority of people with PD, and research has shown that cough function is also impaired. Previous studies suggest that testing reflex cough by having participants inhale a cough-inducing stimulus through a nebulizer may be a reliable indicator of swallowing dysfunction, or dysphagia. The primary goal of this study was to determine the cough response to two different cough-inducing stimuli in people with and without PD. The second goal of this study was to compare the cough response to the two different stimuli in people with PD, with and without swallowing dysfunction. Seventy adults (49 healthy and 21 with PD) participated in the study. Aerosolized water (fog) and 200 μM capsaicin were used to induce cough. Each substance was placed in a small, hand-held nebulizer, and presented to the participant. Each cough stimulus was presented three times. The total number of coughs produced to each stimulus trial was recorded. All participants coughed more to capsaicin versus fog (p dysphagia. The data show a differential response of the PD participants to the capsaicin versus fog stimuli. Clinically, this finding may allow for earlier identification of people with PD who are in need of a swallowing evaluation. As well, there are implications for the neural control of cough in this patient population.

Acoustic startle reflex and pre-pulse inhibition in tinnitus patients

Institute of Scientific and Technical Information of China (English)

Kelly Shadwick; Wei Sun

2014-01-01

Gap induced pre-pulse inhibition (Gap-PPI) of acoustic startle reflex has been used as a measurement of tinnitus in animal models. However, whether this test is sensitive to detect tinnitus in humans is still unclear. Based on the testing procedure used in animal studies, a human subject testing method was formulated and conducted to investigate if a similar result could be found in tinnitus patients. Audiologic and tinnitus assessments and acoustic startle reflex measurements were performed on seven tinnitus subjects and nine age matched subjects without tinnitus. There was no significant difference found between the control and tinnitus group on the Gap-PPI across the frequencies evaluated. The amplitude of the startle response in the tinnitus group with normal hearing thresholds was significantly higher than the control group and those with tinnitus and hearing loss. This preliminary result suggests that hyperexcitability in the central auditory system may be involved in tinnitus. There was no correlation between hearing thresholds and the increased amplitude of startle response.

Cough reflex sensitization from esophagus and nose.

Science.gov (United States)

Hennel, Michal; Brozmanova, Mariana; Kollarik, Marian

2015-12-01

The diseases of the esophagus and nose are among the major factors contributing to chronic cough although their role in different patient populations is debated. Studies in animal models and in humans show that afferent C-fiber activators applied on esophageal or nasal mucosa do not initiate cough, but enhance cough induced by inhaled irritants. These results are consistent with the hypothesis that activation of esophageal and nasal C-fibers contribute to cough reflex hypersensitivity observed in chronic cough patients with gastroesophageal reflux disease (GERD) and chronic rhinitis, respectively. The afferent nerves mediating cough sensitization from the esophagus are probably the neural crest-derived vagal jugular C-fibers. In addition to their responsiveness to high concentration of acid typical for gastroesophageal reflux (pH acidic reflux such as receptors highly sensitive to acid and receptors for bile acids. The nature of sensory pathways from the nose and their activators relevant for cough sensitization are less understood. Increased cough reflex sensitivity was also reported in many patients with GERD or rhinitis who do not complain of cough indicating that additional endogenous or exogenous factors may be required to develop chronic coughing in these diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Altered Neuromodulatory Drive May Contribute to Exaggerated Tonic Vibration Reflexes in Chronic Hemiparetic Stroke

Directory of Open Access Journals (Sweden)

Jacob G. McPherson

2018-04-01

Full Text Available Exaggerated stretch-sensitive reflexes are a common finding in elbow flexors of the contralesional arm in chronic hemiparetic stroke, particularly when muscles are not voluntarily activated prior to stretch. Previous investigations have suggested that this exaggeration could arise either from an abnormal tonic ionotropic drive to motoneuron pools innervating the paretic limbs, which could bring additional motor units near firing threshold, or from an increased influence of descending monoaminergic neuromodulatory pathways, which could depolarize motoneurons and amplify their responses to synaptic inputs. However, previous investigations have been unable to differentiate between these explanations, leaving the source(s of this excitability increase unclear. Here, we used tonic vibration reflexes (TVRs during voluntary muscle contractions of increasing magnitude to infer the sources of spinal motor excitability in individuals with chronic hemiparetic stroke. We show that when the paretic and non-paretic elbow flexors are preactivated to the same percentage of maximum prior to vibration, TVRs remain significantly elevated in the paretic arm. We also show that the rate of vibration-induced torque development increases as a function of increasing preactivation in the paretic limb, even though the amplitude of vibration-induced torque remains conspicuously unchanged as preactivation increases. It is highly unlikely that these findings could be explained by a source that is either purely ionotropic or purely neuromodulatory, because matching preactivation should control for the effects of a potential ionotropic drive (and lead to comparable tonic vibration reflex responses between limbs, while a purely monoaminergic mechanism would increase reflex magnitude as a function of preactivation. Thus, our results suggest that increased excitability of motor pools innervating the paretic limb post-stroke is likely to arise from both ionotropic and

Role of TRPV1 in acupuncture modulation of reflex excitatory cardiovascular responses.

Science.gov (United States)

Guo, Zhi-Ling; Fu, Liang-Wu; Su, Hou-Fen; Tjen-A-Looi, Stephanie C; Longhurst, John C

2018-05-01

We have shown that acupuncture, including manual and electroacupuncture (MA and EA), at the P5-6 acupoints stimulates afferent fibers in the median nerve (MN) to modulate sympathoexcitatory cardiovascular reflexes through central regulation of autonomic function. However, the mechanisms underlying acupuncture activation of these sensory afferent nerves and their cell bodies in the dorsal root ganglia (DRG) are unclear. Transient receptor potential vanilloid type 1 (TRPV1) is present in sensory nerve fibers distributed in the general region of acupoints like ST36 and BL 40 located in the hindlimb. However, the contribution of TRPV1 to activation of sensory nerves by acupuncture, leading to modulation of pressor responses, has not been studied. We hypothesized that TRPV1 participates in acupuncture's activation of sensory afferents and their associated cell bodies in the DRG to modulate pressor reflexes. Local injection of iodoresiniferatoxin (Iodo-RTX; a selective TRPV1 antagonist), but not 5% DMSO (vehicle), into the P6 acupoint on the forelimb reversed the MA's inhibition of pressor reflexes induced by gastric distension (GD). Conversely, inhibition of GD-induced sympathoexcitatory responses by EA at P5-6 was unchanged after administration of Iodo-RTX into P5-6. Single-unit activity of Group III or IV bimodal afferents sensitive to both mechanical and capsaicin stimuli responded to MA stimulation at P6. MA-evoked activity was attenuated significantly ( P < 0.05) by local administration of Iodo-RTX ( n = 12) but not by 5% DMSO ( n = 12) into the region of the P6 acupoint in rats. Administration of Iodo-RTX into P5-6 did not reduce bimodal afferent activity evoked by EA stimulation ( n = 8). Finally, MA at P6 and EA at P5-6 induced phosphorylation of extracellular signal-regulated kinases (ERK; an intracellular signaling messenger involved in cellular excitation) in DRG neurons located at C 7-8 spinal levels receiving MN inputs. After TRPV1 was knocked down in the

Orientation dependence in collision induced electronic relaxation studied through van der Waals complexes with isomeric structures. Invited feature article

International Nuclear Information System (INIS)

Cheng, P.Y.; Lapierre, L.; Ju, S.S.; DeRose, P.; Dai, H.L.

1994-01-01

Weakly bound molecular complexes with more than one well-defined structures provide us with an unique opportunity to investigate dynamic processes induced by intermolecular interactions with specific orientations. The relative orientation of the two interacting molecules or atoms is defined by the complex structure. The effect of the orientation in the spin changing collisions glyoxal (S 1 ) + Ar → glyoxal (T 1 ) + Ar and acetylene (S 1 ) + Ar → acetylene (T) + Ar have been studied by measuring the intersystem crossing (ISC) rates of the glyoxal(S 1 ).Ar and acetylene(S 1 ).Ar complexes with different isomeric structures. Results show that there is a strong orientation dependence in the ISC of glyoxal(S 1 ) induced by interaction with the Ar atom: the Ar atom positioned in the molecular plane is much more effective than in the out-of-plane position in inducing the S 1 → T 1 transition of glyoxal. On the other hand, studies of acetylene(S 1 ).Ar complexes indicate that the Ar-induced ISC rates are nearly identical for the in-plane and out-of-plane positions. Orientation dependence in the collision induced vibrational relaxation process C 2 H 2 (S 1 , v i ) + Ar → C 2 H 2 (S 1 , v f i ) + Ar is also studied by measuring the vibrational predissociation rates of the acetylene(S 1 ).Ar complex isomers. The results indicate that collisions of C 2 H 2 (S 1 , v 3 = 3, 4) with Ar at two orthogonal orientations are equally effective in causing vibrational relaxation of C 2 H 2 . (orig.)

Using ESO Reflex with Web Services

Science.gov (United States)

Järveläinen, P.; Savolainen, V.; Oittinen, T.; Maisala, S.; Ullgrén, M. Hook, R.

2008-08-01

ESO Reflex is a prototype graphical workflow system, based on Taverna, and primarily intended to be a flexible way of running ESO data reduction recipes along with other legacy applications and user-written tools. ESO Reflex can also readily use the Taverna Web Services features that are based on the Apache Axis SOAP implementation. Taverna is a general purpose Web Service client, and requires no programming to use such services. However, Taverna also has some restrictions: for example, no numerical types such integers. In addition the preferred binding style is document/literal wrapped, but most astronomical services publish the Axis default WSDL using RPC/encoded style. Despite these minor limitations we have created simple but very promising test VO workflow using the Sesame name resolver service at CDS Strasbourg, the Hubble SIAP server at the Multi-Mission Archive at Space Telescope (MAST) and the WESIX image cataloging and catalogue cross-referencing service at the University of Pittsburgh. ESO Reflex can also pass files and URIs via the PLASTIC protocol to visualisation tools and has its own viewer for VOTables. We picked these three Web Services to try to set up a realistic and useful ESO Reflex workflow. They also demonstrate ESO Reflex abilities to use many kind of Web Services because each of them requires a different interface. We describe each of these services in turn and comment on how it was used

Prevalence of family history in patients with reflex syncope

DEFF Research Database (Denmark)

Holmegard, Haya N; Benn, Marianne; Kaijer, Michelle Nymann

2013-01-01

Reflex syncope is defined by a rapid transient loss of consciousness caused by global cerebral hypoperfusion resulting from vasodilatation and/or bradycardia attributable to inappropriate cardiovascular reflexes. A hereditary component has been suggested, but prevalence of family history may differ...... among subtypes of reflex syncope, as these have different autonomic responses and pathogeneses may be diverse. The present study aimed to assess the prevalence of a positive family history of syncope and cardiovascular characteristics in patients with cardioinhibitory and vasodepressor reflex syncope....... Patients (n=74) were classified into subtypes of reflex syncope - cardioinhibition/asystole (Vasovagal Syncope International Study subtypes II-B [VASIS II-B], n=38) or vasodepressor (VASIS III, n=36) - using the head-up tilt test. Family history was obtained by questionnaires supplemented by interview...

Increase in H-reflex gain following 1 week of immobilization

DEFF Research Database (Denmark)

Jensen, Jesper Lundbye; Sørensen, Mie; Nielsen, Jens Bo

It is well established that motor experience induces structural and functional plasticity within the central nervous system. It is less well investigated whether reduced motor activity in relation to immobilization is also associated with plastic neuronal changes. The present experiment examined ...... removal all measurements had returned to preimmobilization levels. These results show that immobilization of only one week duration is associated with reversible adaptive changes in the gain of the central part of the monosynaptic stretch reflex....

Modification of Otolith-Ocular Reflexes, Motion Perception and Manual Control During Variable Radius Centrifugation Following Space Flight

Science.gov (United States)

Wood, Scott J.; Clarke, A. H.; Rupert, A. H.; Harm, D. L.; Clement, G. R.

2009-01-01

Two joint ESA-NASA studies are examining changes in otolith-ocular reflexes and motion perception following short duration space flights, and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. Data is currently being collected on astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation is utilized to elicit otolith reflexes in the lateral plane without concordant roll canal cues. Unilateral centrifugation (400 deg/s, 3.5 cm radius) stimulates one otolith positioned off-axis while the opposite side is centered over the axis of rotation. During this paradigm, roll-tilt perception is measured using a subjective visual vertical task and ocular counter-rolling is obtained using binocular video-oculography. During a second paradigm (216 deg/s, less than 20 cm radius), the effects of stimulus frequency (0.15 - 0.6 Hz) are examined on eye movements and motion perception. A closed-loop nulling task is also performed with and without vibrotactile display feedback of chair radial position. Data collection is currently ongoing. Results to date suggest there is a trend for perceived tilt and translation amplitudes to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. One result of this study will be to characterize the variability (gain, asymmetry) in both otolith-ocular responses and motion perception during variable radius centrifugation, and measure the time course of post-flight recovery. This study will also address how adaptive changes in otolith-mediated reflexes correspond to one's ability to perform closed-loop nulling tasks following G-transitions, and whether manual control performance can be improved

Ultimate concerns in late modernity: Archer, Bourdieu and reflexivity.

Science.gov (United States)

Farrugia, David; Woodman, Dan

2015-12-01

Through a critique of Margaret Archer's theory of reflexivity, this paper explores the theoretical contribution of a Bourdieusian sociology of the subject for understanding social change. Archer's theory of reflexivity holds that conscious 'internal conversations' are the motor of society, central both to human subjectivity and to the 'reflexive imperative' of late modernity. This is established through critiques of Bourdieu, who is held to erase creativity and meaningful personal investments from subjectivity, and late modernity is depicted as a time when a 'situational logic of opportunity' renders embodied dispositions and the reproduction of symbolic advantages obsolete. Maintaining Archer's focus on 'ultimate concerns' in a context of social change, this paper argues that her theory of reflexivity is established through a narrow misreading and rejection of Bourdieu's work, which ultimately creates problems for her own approach. Archer's rejection of any pre-reflexive dimensions to subjectivity and social action leaves her unable to sociologically explain the genesis of 'ultimate concerns', and creates an empirically dubious narrative of the consequences of social change. Through a focus on Archer's concept of 'fractured reflexivity', the paper explores the theoretical necessity of habitus and illusio for understanding the social changes that Archer is grappling with. In late modernity, reflexivity is valorized just as the conditions for its successful operation are increasingly foreclosed, creating 'fractured reflexivity' emblematic of the complex contemporary interaction between habitus, illusio, and accelerating social change. © London School of Economics and Political Science 2015.

Reflexive Aero Structures for Enhanced Survivability, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Cornerstone Research Group Inc. (CRG) proposes to develop an advanced reflexive structure system to increase the survivability of aerostructures. This reflexive...

Anticausatives are weak scalar expressions, not reflexive expressions

Directory of Open Access Journals (Sweden)

Florian Schäfer

2016-07-01

Full Text Available We discuss conceptual and empirical arguments from Germanic, Romance and Slavic languages against an analysis treating anticausative verbs as derived from their lexical causative counterparts under reflexivization. Instead, we defend the standard account to the semantics of the causative alternation according to which anticausatives in general, and anticausatives marked with reflexive morphology in particular, denote simple one-place inchoative events that are logically entailed by their lexical causative counterparts. Under such an account, anticausative verbs are weak scalar expressions that stand in a semantico-pragmatic opposition to their strong lexical causative counterparts. Due to this scalar relation, the use of an anticausative can trigger the implicature that the use of its lexical causative counterpart is too strong. As usual with implicatures, they can be ‘metalinguistically’ denied, cancelled, or reinforced and we argue that these mechanisms explain all central empirical facts brought up in the literature in favor of a treatment of anticausatives as semantically reflexive predicates. Our results reinforce the view that the reflexive morphemes used in many (Indo-European languages to mark anticausatives do not necessarily trigger reflexive semantics. However, we also show that a string involving a reflexively marked (anti-causative verb can be forced into a semantically reflexive construal under particular conceptual or grammatical circumstances.

Reflexive Planning as Design and Work

DEFF Research Database (Denmark)

Lissandrello, Enza; Grin, John

2011-01-01

in planning emerges as a new tool for generating critical knowledge and dialogue that can synthesise the perspectives of multiple actors in a common understanding, existing structural constraints and a collective imagination of alternative future possibilities. Such research highlights the potential......In recent years, planning theorists have advanced various interpretations of the notion of reflexivity, inspired by American pragmatism, complexity theory, hermeneutics, discursive and collaborative planning. Scholars agree that “reflexivity” has a strong temporal dimension: it not only aims...... to solve present planning problems, but to imagine and understand alternative trajectories for future action. This article explores the practical utility of reflexivity for planners, through a case study that focuses on a project to promote sustainable development in the Port of Amsterdam. Reflexivity...

The effects of prepulse-blink reflex trial repetition and prepulse change on blink reflex modification at short and long lead intervals.

Science.gov (United States)

Lipp, O V; Siddle, D A

1998-01-01

Prepulse inhibition and facilitation of the blink reflex are said to reflect different responses elicited by the lead stimulus, transient detection and orienting response respectively. Two experiments investigated the effects of trial repetition and lead stimulus change on blink modification. It was hypothesized that these manipulations will affect orienting and thus blink facilitation to a greater extent than they will affect transient detection and thus blink inhibition. In Experiment 1 (N = 64), subjects were trained with a sequence of 12 lead stimulus and 12 blink stimulus alone presentations, and 24 lead stimulus-blink stimulus pairings. Lead interval was 120 ms for 12 of the trials and 2000 ms for the other 12. For half the subjects this sequence was followed by a change in pitch of the lead stimulus. In Experiment 2 (N = 64), subjects were trained with a sequence of 36 blink alone stimuli and 36 lead stimulus-blink stimulus pairings. The lead interval was 120 ms for half the subjects and 2000 ms for the other half. The pitch of the lead stimulus on prestimulus trials 31-33 was changed for half the subjects in each group. In both experiments, the amount of blink inhibition decreased during training whereas the amount of blink facilitation remained unchanged. Lead stimulus change had no effect on blink modification in either experiment although it resulted in enhanced skin conductance responses and greater heart rate deceleration in Experiment 2. The present results are not consistent with the notion that blink facilitation is linked to orienting whereas blink inhibition reflects a transient detection mechanism.

Voluntary Control of the Near Reflex: A Case Report

Directory of Open Access Journals (Sweden)

Serpil Akar

2014-03-01

Full Text Available Spasm of the near reflex is a rare disorder that involves intermittent and variable episodes of esotropia, pseudomyopia, and pupillary myosis. It is usually functional in origin and is seen mainly in young patients. Treatment options for spasm of the near reflex have had variable success. In instances where the etiology of spasm of the near reflex was suspected to be hysteria, psychotherapy has proven beneficial. We report the case of an 11-year-old girl who had functional spasm of the near reflex. The symptoms persisted for two years. Symptomatic relief was achieved by cycloplegia and spectacle correction (added plus lenses at near. The patient also underwent psychological counseling. In our case, the functional spasm of the near reflex spontaneously resolved after 2 years. (Turk J Ophthalmol 2014; 44: 161-3

Rock stress orientation measurements using induced thermal spalling in slim boreholes

International Nuclear Information System (INIS)

Hakami, Eva

2011-05-01

In the planning and design of a future underground storage for nuclear waste based on the KBS-3 method, one of the aims is to optimize the layout of deposition tunnels such that the rock stresses on the boundaries of deposition holes are minimized. Previous experiences from heating of larger scale boreholes at the Aespoe Hard Rock Laboratory (AHRL) gave rise to the idea that induced borehole breakouts using thermal loading in smaller diameter boreholes, could be a possible way of determining the stress orientation. Two pilot experiments were performed, one at the Aespoe Hard Rock Laboratory and one at ONKALO research site in Finland. An acoustic televiewer logger was used to measure the detailed geometrical condition of the borehole before and after heating periods. The acoustic televiewer gives a value for each 0.7 mm large pixel size around the borehole periphery. The results from the loggers are presented as images of the borehole wall, and as curves for the maximum, mean and minimum values at each depth. Any changes in the borehole wall geometry may thus be easily detected by comparisons of the logging result images. In addition, using an optical borehole televiewer a good and detailed realistic colour picture of the borehole wall is obtained. From these images the character of the spalls identified may be evaluated further. The heating was performed in a 4 m long section, using a heating cable centred in an 8 m deep vertical borehole, drilled from the floor of the tunnels. For the borehole in the Q-tunnel of AHRL the results from the loggings of the borehole before the heating revealed that breakouts existed even before this pilot test due to previous heating experiments at the site (CAPS). Quite consistent orientation and the typical shape of small breakouts were observed. After the heating the spalling increased slightly at the same locations and a new spalling location also developed at a deeper location in the borehole. At ONKALO three very small changes

Rock stress orientation measurements using induced thermal spalling in slim boreholes

Energy Technology Data Exchange (ETDEWEB)

Hakami, Eva [Geosigma AB, Uppsala (Sweden)

2011-05-15

In the planning and design of a future underground storage for nuclear waste based on the KBS-3 method, one of the aims is to optimize the layout of deposition tunnels such that the rock stresses on the boundaries of deposition holes are minimized. Previous experiences from heating of larger scale boreholes at the Aespoe Hard Rock Laboratory (AHRL) gave rise to the idea that induced borehole breakouts using thermal loading in smaller diameter boreholes, could be a possible way of determining the stress orientation. Two pilot experiments were performed, one at the Aespoe Hard Rock Laboratory and one at ONKALO research site in Finland. An acoustic televiewer logger was used to measure the detailed geometrical condition of the borehole before and after heating periods. The acoustic televiewer gives a value for each 0.7 mm large pixel size around the borehole periphery. The results from the loggers are presented as images of the borehole wall, and as curves for the maximum, mean and minimum values at each depth. Any changes in the borehole wall geometry may thus be easily detected by comparisons of the logging result images. In addition, using an optical borehole televiewer a good and detailed realistic colour picture of the borehole wall is obtained. From these images the character of the spalls identified may be evaluated further. The heating was performed in a 4 m long section, using a heating cable centred in an 8 m deep vertical borehole, drilled from the floor of the tunnels. For the borehole in the Q-tunnel of AHRL the results from the loggings of the borehole before the heating revealed that breakouts existed even before this pilot test due to previous heating experiments at the site (CAPS). Quite consistent orientation and the typical shape of small breakouts were observed. After the heating the spalling increased slightly at the same locations and a new spalling location also developed at a deeper location in the borehole. At ONKALO three very small changes

Nanoscale characterization of the evolution of the twin–matrix orientation in Fe–Mn–C twinning-induced plasticity steel by means of transmission electron microscopy orientation mapping

International Nuclear Information System (INIS)

Albou, A.; Galceran, M.; Renard, K.; Godet, S.; Jacques, P.J.

2013-01-01

The evolution of the orientation relationship between mechanical twins and the surrounding matrix with the degree of plastic deformation has been characterized at the nanoscale in twinning-induced plasticity steel. The recently developed automated crystal orientation mapping in transmission electron microscopy revealed that the ideal twin relationship is retained up to large levels of strain, while large orientation gradients are built up within the matrix. This particular evolution undoubtedly plays a role in the large work hardening rate of these steels.

Suppressive effect of pectic polysaccharides from Cucurbita pepo L. var. Styriaca on citric acid-induced cough reflex in guinea pigs.

Science.gov (United States)

Nosáľová, Gabriela; Prisenžňáková, Lubica; Košťálová, Zuzana; Ebringerová, Anna; Hromádková, Zdenka

2011-04-01

Several water-soluble pectic polysaccharides were isolated from the pumpkin fruit biomass and characterized by composition, structural features and molecular properties. The pectic polysaccharides were tested for antitussive activity by studying the effects of citric acid-induced cough reflex in guinea pigs and reactivity of the airway smooth muscle in vivo conditions in comparison to the narcotic drug codeine. Oral administration of all pectic polysaccharides from pumpkin inhibited the number of coughs induced by citric acid in guinea pigs, but to various extents. The results indicated that the antitussive activity of the pectic polysaccharides is affected by their molecular and structural properties, whereby a synergistic action between the polysaccharide and non-carbohydrate components on the biological response has been suggested as well. The cough depressive efficacy of most of the tested polysaccharides was comparable and even higher than that of codeine. Moreover, the application of these polysaccharides provoked any side effects what is their advantage towards the conventional opioid-derived antitussive agents. Copyright © 2010 Elsevier B.V. All rights reserved.

Laser-induced nuclear orientation and gamma anisotropy in sodium

International Nuclear Information System (INIS)

Pappas, P.G.

1980-12-01

The use of laser optical pumping to induce nuclear orientation in several isotopes and one isomer of atomic sodium vapor is described. Essentially complete nuclear polarization, P > 90%, has been achieved in stable 23 Na when pumping with modest laser intensities (I approx. = 10 mW/cm 2 ). The volume of the sample cell was approximately 10 cc, and was filled with a sodium density of about 10'' atoms/cc. Complete coverage of the Doppler distribution was accomplished with the use of trace amounts (less than or equal to 1 torr) of argon buffer gas to induce velocity changing collisions. A theoretical model which accurately predicts the amount of polarization is developed. The orientation of nuclei which are unstable to gamma decay can manifest itself in anisotropic gamma ray emission. This anisotropy can be used to measure isotope and isomer shifts, from which nuclear properties can be derived. Gamma anisotropy was observed in two systems, 22 Na and /sup 24m/Na. From the observed anisotropy in /sup 24m/Na, a negative sign for the g factor is determined. Values are derived for the magnetic moment, μ = 2.56 +- 0.64 nm, and the isomer shift, deltaν/sub 24m/ = 288 +- 191 MHz (D1 line). A model is described which relates various laser and fubber gas parameters to the observed gamma anisotropy lineshape. This model facilitates the extraction of physical parameters from knowledge of the laser frequency at which the anisotropy is a maximum

Post-activation depression of soleus stretch reflexes in healthy and spastic humans

DEFF Research Database (Denmark)

Grey, Michael James; Klinge, Klaus; Crone, Clarissa

2007-01-01

Reduced depression of transmitter release from Ia afferents following previous activation (post-activation depression) has been suggested to be involved in the pathophysiology of spasticity. However, the effect of this mechanism on the myotatic reflex and its possible contribution to increased...... reflex excitability in spastic participants has not been tested. To investigate these effects, we examined post-activation depression in Soleus H-reflex responses and in mechanically evoked Soleus stretch reflex responses. Stretch reflex responses were evoked with consecutive dorsiflexion perturbations...... of the soleus stretch reflex and H-reflex decreased as the interval between the stimulus/perturbation was decreased. Similarly, the stretch-evoked torque decreased. In the spastic participants, the post-activation depression of both reflexes and the stretch-evoked torque was significantly smaller than...

Electroacupuncture improves gait locomotion, H-reflex and ventral root potentials of spinal compression injured rats.

Science.gov (United States)

Escobar-Corona, Carlos; Torres-Castillo, Sergio; Rodríguez-Torres, Erika Elizabeth; Segura-Alegría, Bertha; Jiménez-Estrada, Ismael; Quiroz-González, Salvador

2017-05-01

This study explored the effect of electroacupuncture stimulation (EA) on alterations in the Hoffman reflex (H-reflex) response and gait locomotion provoked by spinal cord injury (SCI) in the rat. A compression lesion of the spinal cord was evoked by insufflating a Fogarty balloon located in the epidural space at the T8-9 spinal level of adult Wistar male rats (200-250 gr; n=60). In different groups of SCI rats, EA (frequencies: 2, 50 and 100Hz) was applied simultaneously to Huantiao (GB30), Yinmen (BL37), Jizhong (GV6) and Zhiyang (GV9) acupoints from the third post-injury day until the experimental session. At 1, 2, 3 and 4 post-injury weeks, the BBB scores of the SCI group of rats treated with EA at 50Hz showed a gradual but greater enhancement of locomotor activity than the other groups of rats. Unrestrained gait kinematic analysis of SCI rats treated with EA-50Hz stimulation showed a significant improvement in stride duration, length and speed (p<0.05), whereas a discrete recovery of gait locomotion was observed in the other groups of animals. After four post-injury weeks, the H-reflex amplitude and H-reflex/M wave amplitude ratio obtained in SCI rats had a noticeable enhancement (217%) compared to sham rats (n=10). Meanwhile, SCI rats treated with EA at 50Hz manifested a decreased facilitation of the H-reflex amplitude and H/M amplitude ratio (154%) and a reduced frequency-dependent amplitude depression of the H-reflex (66%). In addition, 50 Hz-EA treatment induced a recovery of the presynaptic depression of the Gs-VRP evoked by PBSt conditioning stimulation in the SCI rat (63.2±8.1%; n=9). In concordance with the latter, it could be suggested that 50 Hz-EA stimulation reduced the hyper-excitability of motoneurons and provokes a partial improvement of the locomotive performance and H reflex responses by a possible recovery of presynaptic mechanisms in the spinal cord of experimentally injured rats. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of fatigue on hamstring reflex responses and posterior-anterior tibial translation in men and women.

Directory of Open Access Journals (Sweden)

Martin Behrens

Full Text Available Anterior cruciate ligament (ACL rupture ranks among the most common injuries in sports. The incidence of ACL injuries is considerably higher in females than in males and the underlying mechanisms are still under debate. Furthermore, it has been suggested that muscle fatigue can be a risk factor for ACL injuries. We investigated gender differences in hamstring reflex responses and posterior-anterior tibial translation (TT before and after fatiguing exercise. We assessed the isolated movement of the tibia relative to the femur in the sagittal plane as a consequence of mechanically induced TT in standing subjects. The muscle activity of the hamstrings was evaluated. Furthermore, isometric maximum voluntary torque (iMVT and rate of torque development (RTD of the hamstrings (H and quadriceps (Q were measured and the MVT H/Q as well as the RTD H/Q ratios were calculated. After fatigue, reflex onset latencies were enhanced in women. A reduction of reflex responses associated with an increased TT was observed in females. Men showed no differences in these parameters. Correlation analysis revealed no significant associations between parameters for TT and MVT H/Q as well as RTD H/Q. The results of the present study revealed that the fatigue protocol used in this study altered the latency and magnitude of reflex responses of the hamstrings as well as TT in women. These changes were not found in men. Based on our results, it is conceivable that the fatigue-induced decrease in neuromuscular function with a corresponding increase in TT probably contributes to the higher incidence of ACL injuries in women.

Tutoring and Mentoring: An A.R.C. Model for Future Teachers: Affective, Reflexive and Cognitive Orientation to Self-Regulated Learning

Science.gov (United States)

Remy, Philippe

2015-01-01

With a specific focus on tutoring among future teachers this article proposes a model of self-regulated learning. The focus on different mechanisms inherent to the tutoring relationship will consider Affective impacts or motivation, Reflexive or metacognitive and Cognitive resolutions. The ARC combination proposes that personal skills will be…

21 CFR 890.1450 - Powered reflex hammer.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Powered reflex hammer. 890.1450 Section 890.1450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... hammer. (a) Identification. A powered reflex hammer is a motorized device intended for medical purposes...

Effects of postural changes of the upper limb on reflex transmission in the lower limb. Cervicolumbar reflex interactions in man.

Science.gov (United States)

Delwaide, P J; Figiel, C; Richelle, C

1977-06-01

The influence of passive changes in upper limb position on the excitability of three myotatic arc reflexes (soleus, quadriceps, and biceps femoris) of the lower limb has been explored on 42 volunteers. The results indicate that the excitability of the three myotatic arcs can be influenced at a distance by postural modifications of the upper limb. When the ipsilateral upper limb is forwards or the contralateral backwards, a facilitation of both soleus and quadriceps tendon reflexes is observed while the biceps femoris reflexes are reduced. This pattern of facilitation and inhibition is reversed when the ipsilateral upper limb is backwards or the contralateral forwards. The facilitations as well as inhibitions of proximal myotatic arc reflexes are quantitatively more marked than that of the soleus reflex. Facilitation and inhibition are not linearly related to the angle of the arm with the trunk. Effects begin at a considerable angle, become maximal at 45 degrees, and progressively disappear for greater values. It is suggested that the distinct pattern of facilitation and inhibition which is exerted in reciprocal fashion on extensor and flexor motor nuclei might depend on the long propriospinal neurones connecting cervical and lumbar enlargements.

Effect of sildenafil (Viagra® on the genital reflexes of paradoxical sleep-deprived male rats

Directory of Open Access Journals (Sweden)

M.L. Andersen

2007-11-01

Full Text Available Since there is evidence that paradoxical sleep deprivation (PSD elicits penile erection (PE and ejaculation (EJ, and that the erectile response of rats is mediated by nitric oxide, the present study sought to extend the latter finding by assessing the effects of sildenafil on the genital reflexes of male Wistar rats subjected to PSD. We also determined the influence of sildenafil on hormone concentrations. In the first experiment, sildenafil at doses ranging from 0.08 to 0.32 mg/kg was administered intraperitoneally to rats that had been deprived of sleep for 4 days and to home cage controls (N = 8-10/group. The frequency of PE and EJ was measured for 60 min. PSD alone induced PE in 50% of the animals; however, a single injection of sildenafil did not significantly increase the percentage of rats displaying PE compared to PSD-saline or to home cage groups. PSD alone also induced spontaneous EJ, but this response was not potentiated by sildenafil in the dose range tested. Testosterone concentrations were significantly lower in PSD rats (137 ± 22 ng/dL than in controls (365 ± 38 ng/dL, whereas progesterone (0.9 ± 0.1 vs 5.4 ± 1 ng/mL and plasma dopamine (103.4 ± 30 vs 262.6 ± 77 pg/mL increased. These changes did not occur after sildenafil treatment. The data show that although sildenafil did not alter the frequency of genital reflexes, it antagonized hormonal (testosterone and progesterone and plasma dopamine changes induced by PSD. The stimulation of the genital reflexes by sildenafil did not result in potentiating effects in PSD rats.

Outside home. Notes on reflexivity

Directory of Open Access Journals (Sweden)

Mara Clemente

2017-01-01

The paper proffers the idea in which a “reflexive process” on subjectivity can involve and/or hopefully involve the entire experience of the researcher, going beyond the borders of a single research. In the process, unexpected elements of subjectivity can come into play; in other cases the meaning attributed to them can change in time or can have a role different from what had been expected. Some elements, objects of epistemological analyses, as imposed by a reflexive approach, can become objects of attention also on the phenomenological level.

The Multiple Faces of Reflexive Research Designs

Directory of Open Access Journals (Sweden)

Karl H. Müller

2015-10-01

Full Text Available Reflexive research can be grouped into five clusters with circular relations between two elements x ↔ x, namely circular relations between observers, between scientific building blocks like concepts, theories or models, between systemic levels, between rules and rule systems or as circular relations or x ↔ y between these four components. By far the most important cluster is the second cluster which becomes reflexive through a re-entry operation RE into a scientific element x and which establishes its circular formation as x(x. Many of the research problems in these five clusters in reflexivity research are still unexplored and pose grand challenges for future research.

A Prototype Analysis of Spanish Indeterminate Reflexive Constructions.

Science.gov (United States)

Turley, Jeffrey S.

1998-01-01

Discussion of the Spanish indeterminate reflexive construction, the impersonal reflexive, finds that prototype theory allows this subjectless Spanish construction to be included within the category of generally subject-bearing indeterminates in Romance languages. (MSE)

Inhibition of swallowing reflex following phosphorylation of extracellular signal-regulated kinase in nucleus tractus solitarii neurons in rats with masseter muscle nociception.

Science.gov (United States)

Tsujimura, Takanori; Kitagawa, Junichi; Ueda, Koichiro; Iwata, Koichi

2009-02-06

Pain is associated with swallowing abnormalities in dysphagic patients. Understanding neuronal mechanisms underlying the swallowing abnormalities associated with orofacial abnormal pain is crucial for developing new methods to treat dysphagic patients. However, how the orofacial abnormal pain is involved in the swallowing abnormalities is not known. In order to evaluate neuronal mechanisms of modulation of the swallows by masticatory muscle pain, here we first induced swallows by topical administration of distilled water to the pharyngolaryngeal region. The swallowing reflex was significantly inhibited after capsaicin (10, 30mM) injection into the masseter muscle compared to vehicle injection. Moreover the number of phosphorylated extracellular signal-regulated kinase-like immunoreactive (pERK-LI) neurons in the nucleus tractus solitarii (NTS) was significantly increased in the rats with capsaicin injection into the masseter muscle compared to that with vehicle injection. Rostro-caudal distribution of pERK-LI neurons in the NTS was peaked at the obex level. The capsaicin-induced inhibitory effect on swallowing reflex was reversed after intrathecal administration of mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitor, PD98059. The present findings suggest that phosphorylation of ERK in NTS neurons may be involved in capsaicin-induced inhibition of swallowing reflex.

Report on a membership audit of the Association of Chartered Physiotherapists in Reflex Therapy (ACPIRT).

Science.gov (United States)

Berry, Gunnel; Svarovska, Beth

2014-08-01

Reflex Therapy (RT), akin to reflexology, is a non-invasive physiotherapy modality approved by the UK Chartered Society of Physiotherapists. One hundred members of the Association of Chartered Physiotherapists in Reflex Therapy (ACPIRT) participated in an audit to establish a baseline of practice. Findings indicate that experienced therapists use RT in conjunction with their professional skills to induce relaxation (95%) and reduce pain (86%) for patients with conditions including whiplash injury and chronic pain. According to 68% of respondents, RT is "very good," "good" or "as good as" orthodox physiotherapy practices. Requiring minimal equipment, RT may be as cost effective as orthodox physiotherapy with regards to duration and frequency of treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Changes in soleus H-reflex during walking in middle-aged, healthy subjects

DEFF Research Database (Denmark)

Raffalt, Peter C; Alkjær, Tine; Simonsen, Erik B

2015-01-01

INTRODUCTION: To assess the effect of aging on stretch reflex modulation during walking, soleus H-reflexes obtained in 15 middle-aged (mean age 56.4±6.9 years) and 15 young (mean age 23.7±3.9 years) subjects were compared. METHODS: The H-reflex amplitude, muscle activity (EMG) of the soleus...... and tibialis anterior muscles, and EMG/H-reflex gain were measured during 4-km/h treadmill walking. RESULTS: The normalized H-reflex amplitude was lower in the swing phase for the middle-aged group, and there was no difference in muscle activity. EMG/H-reflex gain did not differ between groups. CONCLUSIONS: H......-reflex amplitude during walking was affected by aging, and changes during the swing phase could be seen in the middle-aged subjects. Subdividing the 2 age groups into groups of facilitated or suppressed swing-phase H-reflex revealed that the H-reflex amplitude modulation pattern in the group with facilitated swing...

Late onset startle induced tics

NARCIS (Netherlands)

Tijssen, MAJ; Brown, P; Morris, HR; Lees, A

1999-01-01

Three cases of late onset Gilles de la Tourette's syndrome are presented. The motor ties were mainly induced by an unexpected startling stimulus, but the startle reflex was not exaggerated. The ties developed after physical trauma or a period of undue emotional stress. Reflex ties may occur in

Late onset startle induced tics

NARCIS (Netherlands)

Tijssen, M. A.; Brown, P.; Morris, H. R.; Lees, A.

1999-01-01

Three cases of late onset Gilles de la Tourette's syndrome are presented. The motor tics were mainly induced by an unexpected startling stimulus, but the startle reflex was not exaggerated. The tics developed after physical trauma or a period of undue emotional stress. Reflex tics may occur in

Orientation dependence of shock-induced twinning and substructures in a copper bicrystal

International Nuclear Information System (INIS)

Cao Fang; Beyerlein, Irene J.; Addessio, Francis L.; Sencer, Bulent H.; Trujillo, Carl P.; Cerreta, Ellen K.; Gray, George T. III

2010-01-01

Shock recovery experiments have been conducted to assess the role of shock stress and orientation dependence on substructure evolution and deformation twinning of a [1 0 0]/[011-bar] copper bicrystal. Transmission electron microscopy of the post-shock specimens revealed that well-defined dislocation cell structures developed in both grains and the average cell size decreased with increasing shock pressure from 5 to 10 GPa. Twinning occurred in the [1 0 0] grain, but not the [011-bar] grain, at the 10 GPa shock pressure. The stress and orientation dependence of incipient twinning can be predicted by the stress and orientation conditions required to dissociate slip dislocations into glissile twinning dislocations. The dynamic widths between the two partials are calculated considering the three-dimensional deviatoric stress state induced by the shock as calculated using plane-strain plate impact simulations and the relativistic and drag effects on dislocations moving at high speeds.

The cough reflex is upregulated by lisinopril microinjected into the caudal nucleus tractus solitarii of the rabbit.

Science.gov (United States)

Cinelli, Elenia; Bongianni, Fulvia; Pantaleo, Tito; Mutolo, Donatella

2015-12-01

We have previously shown that cough potentiation induced by intravenous administration of the AT1 receptor antagonist losartan is lower than that induced by the ACE inhibitor lisinopril in anesthetized and awake rabbits. Since losartan and lisinopril cross the blood-brain barrier, their central action on the cough reflex can be hypothesized. Mechanical stimulation of the tracheobronchial tree and citric acid inhalation were used to induce cough reflex responses in pentobarbital sodium-anesthetized, spontaneously breathing rabbits. Bilateral microinjections (30-50 nl) of losartan (5mM), lisinopril (1mM), bradykinin (0.05 mM), HOE-140 (0.2mM, a bradykinin B2 receptor antagonist) and CP-99,994 (1mM, an NK1 receptor antagonist) were performed into the caudal nucleus tractus solitarii, the predominant site of termination of cough-related afferents. Lisinopril, but not losartan increased the cough number. This effect was reverted by HOE-140 or CP-99,994. Cough potentiation was also induced by bradykinin. The results support for the first time a central protussive action of lisinopril mediated by an accumulation of bradykinin and substance P. Copyright © 2015 Elsevier B.V. All rights reserved.

Thermally-induced amphibole reaction rim development: EBSD insights into microlite orientation

Science.gov (United States)

De Angelis, Sarah; Lavallée, Yan; Larsen, Jessica; Mariani, Elisabetta

2014-05-01

Amphibole is an important mineral present in many calc-alkaline volcanic deposits. A hydrous phase, volcanic amphibole is only stable at pressures greater than 100 MPa (approx. 4 km), temperature less than ~860-870 oC, and in melts containing at least 4 wt % H2O. When removed from their thermal and barometric stability field, amphiboles decompose to form aggregate rims of anhydrous minerals. The thickness, texture, and mineralogy of these rims are thought to be reflective of the process driving amphibole disequilibrium (e.g. heating, decompression, etc). However, significant overlap in rim thicknesses and microlite textures means that distinguishing between processes it not simple. This study employed backscatter diffraction (EBSD) to examine both experimental heating-indced amphibole reaction rims and natural amphibole reaction rim from Augustine Volcano. We collected crystal orientation maps of amphibole reaction rims to investigate if different types of disequilibrium produce different patterns of microlite orientation. We identified two types of reaction rim: Type 1- reaction rim microlites are generally oriented at random and share little or no systematic relationship with the crystallographic orientation of the host amphibole, and; Type 2- reaction rim microlites exhibit a topotactic relationship with the host amphibole (they share the same crystallographic orientation). Experimentally produced heating reaction rims are without exception Type 2. However the natural reaction rims are evenly distributed between Types 1 and 2. Further experimental data on decompression induced reaction rim formation is needed to investigate if Type 1 reaction rims resemble the breakdown of amphibole due to decompression. If so, reaction rim microlite orientation could provide a clear method for distinguishing between heating and decompression processes in amphibole bearing magmas.

Acoustic Reflex Screening of Conductive Hearing Loss for Third Window Disorders.

Science.gov (United States)

Hong, Robert S; Metz, Christopher M; Bojrab, Dennis I; Babu, Seilesh C; Zappia, John; Sargent, Eric W; Chan, Eleanor Y; Naumann, Ilka C; LaRouere, Michael J

2016-02-01

This study examines the effectiveness of acoustic reflexes in screening for third window disorders (eg, superior semicircular canal dehiscence) prior to middle ear exploration for conductive hearing loss. Case series with chart review. Outpatient tertiary otology center. A review was performed of 212 ears with acoustic reflexes, performed as part of the evaluation of conductive hearing loss in patients without evidence of chronic otitis media. The etiology of hearing loss was determined from intraoperative findings and computed tomography imaging. The relationship between acoustic reflexes and conductive hearing loss etiology was assessed. Eighty-eight percent of ears (166 of 189) demonstrating absence of all acoustic reflexes had an ossicular etiology of conductive hearing loss. Fifty-two percent of ears (12 of 23) with at least 1 detectable acoustic reflex had a nonossicular etiology. The positive and negative predictive values for an ossicular etiology were 89% and 57% when acoustic reflexes were used alone for screening, 89% and 39% when third window symptoms were used alone, and 94% and 71% when reflexes and symptoms were used together, respectively. Acoustic reflex testing is an effective means of screening for third window disorders in patients with a conductive hearing loss. Questioning for third window symptoms should complement screening. The detection of even 1 acoustic reflex or third window symptom (regardless of reflex status) should prompt further workup prior to middle ear exploration. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

Evidence for glutamatergic mechanisms in the vagal sensory pathway initiating cardiorespiratory reflexes in the shorthorn sculpin Myoxocephalus scorpius.

Science.gov (United States)

Sundin, L; Turesson, J; Taylor, E W

2003-03-01

Glutamate is a major neurotransmitter of chemoreceptor and baroreceptor afferent pathways in mammals and therefore plays a central role in the development of cardiorespiratory reflexes. In fish, the gills are the major sites of these receptors, and, consequently, the terminal field (sensory area) of their afferents (glossopharyngus and vagus) in the medulla must be an important site for the integration of chemoreceptor and baroreceptor signals. This investigation explored whether fish have glutamatergic mechanisms in the vagal sensory area (Xs) that could be involved in the generation of cardiorespiratory reflexes. The locations of the vagal sensory and motor (Xm) areas in the medulla were established by the orthograde and retrograde axonal transport of the neural tract tracer Fast Blue following its injection into the ganglion nodosum. Glutamate was then microinjected into identified sites within the Xs in an attempt to mimic chemoreceptor- and baroreceptor-induced reflexes commonly observed in fish. By necessity, the brain injections were performed on anaesthetised animals that were fixed by 'eye bars' in a recirculating water system. Blood pressure and heart rate were measured using an arterial cannula positioned in the afferent branchial artery of the 3rd gill arch, and ventilation was measured by impedance probes sutured onto the operculum. Unilateral injection of glutamate (40-100 nl, 10 mmol l(-1)) into the Xs caused marked cardiorespiratory changes. Injection (0.1-0.3 mm deep) in different rostrocaudal, medial-lateral positions induced a bradycardia, either increased or decreased blood pressure, ventilation frequency and amplitude and, sometimes, an initial apnea. Often these responses occurred simultaneously in various different combinations but, occasionally, they appeared singly, suggesting specific projections into the Xs for each cardiorespiratory variable and local determination of the modality of the response. Response patterns related to

Reflex responses of lip muscles in young and older women.

Science.gov (United States)

Wohlert, A B

1996-06-01

The perioral reflex in response to innocuous mechanical stimulation of the lip vermilion was studied in 20 young and 20 older women. Responses to stimuli at the right and left sides of both the upper and lower lips were recorded. Results show significant specificity of response, especially for upper lip sites. Reflex response at the site of stimulation was greatest in amplitude and shortest in latency, followed by response at sites ipsilateral to the site of stimulation. Younger subjects showed greater localizing tendency than older subjects. Stimulation was significantly less likely to produce a reflex response in the older group. When reflex responses did occur, they were significantly lower in amplitude and longer in latency than the responses of the younger group. Nonetheless, reflex responses were common in both groups, with responses at the site of stimulation occurring 78% of the time in older women and 90% of the time in younger women. Every participant showed at least one reflex response to lip stimulation. Results suggest decreasing complexity of synaptic drive to the perioral system in old age but also show that reflexive response does not deteriorate completely, remaining an available element for motor control in normal older women.

Cerebellar interaction with the acoustic reflex.

Science.gov (United States)

Jastreboff, P J

1981-01-01

The involvement of the cerebellar vermis in the acoustic reflex was analyzed in 12 cats, decerebrated or in pentobarbital anesthesia. Anatomical data suggested the existence of a connection of lobules VIII with the ventral cochlear nucleus. Single cell recording and evoked potential techniques demonstrated the existence of the acoustic projection to lobulus VIII. Electrical stimulation of this area changed the tension of the middle ear muscle and caused evoked potential responses in the caudal part of the ventral cochlear nucleus. Electrical stimulation of the motor nucleus of the facial nerve evoked a slow wave in the recording taken from the surrounding of the cochlear round window. A hypothesis is proposed which postulates the involvement of the acoustic reflex in space localization of acoustic stimuli and the action of cerebellar vermis in order to assure the stability and plasticity of the acoustic reflex arc.

Reflex syncope: Diagnosis and treatment

Directory of Open Access Journals (Sweden)

Richard Sutton

2017-12-01

Full Text Available For the diagnosis of reflex syncope, diligent history-building with the patient and a witness is required. In the Emergency Department (ED, the assessment of syncope is a challenge which may be addressed by an ED Observation Unit or by a referral to a Syncope Unit. Hospital admission is necessary for those with life-threatening cardiac conditions although risk stratification remains an unsolved problem. Other patients may be investigated with less urgency by carotid sinus massage (>40 years, tilt testing, and electrocardiogram loop recorder insertion resulting in a clear cause for syncope. Management includes, in general terms, patient education, avoidance of circumstances in which syncope is likely, increase in fluid and salt consumption, and physical counter-pressure maneuvers. In older patients, those that will benefit from cardiac pacing are now well defined. In all patients, the benefit of drug therapy is often disappointing and there remains no ideal drug. A role for catheter ablation may emerge for the highly symptomatic reflex syncope patient. Keywords: Cardiac pacing, Catheter ablation, Diagnosis, Drugs, Management, Reflex syncope

Xe ion beam induced rippled structures on differently oriented single-crystalline Si surfaces

Energy Technology Data Exchange (ETDEWEB)

Hanisch, Antje; Grenzer, Joerg; Facsko, Stefan [Forschungszentrum Dresden-Rossendorf, Institut fuer Ionenstrahlphysik und Materialforschung, PO Box 510119, 01314 Dresden (Germany); Biermanns, Andreas; Pietsch, Ullrich, E-mail: A.Hanisch@fzd.d [Universitaet Siegen, Festkoerperphysik, 57068 Siegen (Germany)

2010-03-24

We report on Xe{sup +} induced ripple formation at medium energy on single-crystalline silicon surfaces of different orientations using substrates with an intentional miscut from the [0 0 1] direction and a [1 1 1] oriented wafer. The ion beam incidence angle with respect to the surface normal was kept fixed at 65{sup 0} and the ion beam projection was parallel or perpendicular to the [1 1 0] direction. By a combination of atomic force microscopy, x-ray diffraction and high-resolution transmission electron microscopy we found that the features of the surface and subsurface rippled structures such as ripple wavelength and amplitude and the degree of order do not depend on the surface orientation as assumed in recent models of pattern formation for semiconductor surfaces. (fast track communication)

The acoustic reflex threshold in aging ears.

Science.gov (United States)

Silverman, C A; Silman, S; Miller, M H

1983-01-01

This study investigates the controversy regarding the influence of age on the acoustic reflex threshold for broadband noise, 500-, 1000-, 2000-, and 4000-Hz activators between Jerger et al. [Mono. Contemp. Audiol. 1 (1978)] and Jerger [J. Acoust. Soc. Am. 66 (1979)] on the one hand and Silman [J. Acoust. Soc. Am. 66 (1979)] and others on the other. The acoustic reflex thresholds for broadband noise, 500-, 1000-, 2000-, and 4000-Hz activators were evaluated under two measurement conditions. Seventy-two normal-hearing ears were drawn from 72 subjects ranging in age from 20-69 years. The results revealed that age was correlated with the acoustic reflex threshold for BBN activator but not for any of the tonal activators; the correlation was stronger under the 1-dB than under the 5-dB measurement condition. Also, the mean acoustic reflex thresholds for broadband noise activator were essentially similar to those reported by Jerger et al. (1978) but differed from those obtained in this study under the 1-dB measurement condition.

Sympathetic reflex control of blood flow in human peripheral tissues

DEFF Research Database (Denmark)

Henriksen, O

1991-01-01

Sympathetic vasoconstrictor reflexes are essential for the maintenance of arterial blood pressure in upright position. It has been generally believed that supraspinal sympathetic vasoconstrictor reflexes elicited by changes in baroreceptor activity play an important role. Recent studies on human...... sympathetic vasoconstrictor reflexes are blocked. Blood flow has been measure by the local 133Xe-technique. The results indicate the presence of spinal as well as supraspinal sympathetic vasoconstrictor reflexes to human peripheral tissues. Especially is emphasized the presence of a local sympathetic veno...... skeletal muscle, cutaneous and subcutaneous tissues of the limbs indicate that the situation is more complex. Measurements have been carried out during acute as well as chronic sympathetic denervation. Spinal sympathetic reflex mechanisms have been evaluated in tetraplegic patients, where supraspinal...

A simple measurement hammer for quantitative reflex studies

NARCIS (Netherlands)

Stam, J.; van Leeuwen, J. R.

1984-01-01

A reflex hammer for measurement of the mechanical stimulus strength was designed. Combined with standard EMG equipment this instrument permits the study of both stimulus-response relations and latencies of myotatic reflexes. Some results in normal subjects are discussed

Subjectivity and Reflexivity in the Social Sciences: Epistemic Windows and Methodical Consequences

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Franz Breuer

2003-05-01

Full Text Available We sketch four basic epistemological assumptions that imply a constructionist orientation to knowledge including (a perspectivity, positionality; (b horizonality, dynamic observer position; (c the structuring of knowledge through instruments of knowledge production; and (d interactivity and interventionist nature of research. Although social scientists often adopt a constructionist epistemology to frame their research object, the methodological consequences of such an epistemology for the production of social scientific knowledge are not normally drawn. Instead of dealing with the four assumptions as a productive epistemic window, many researchers exhibit a defensive tendency and continue the quest for objectivity in their own writing. We propose a different methodological position conceptualized in the dialectic of the always embodied, individual, and social researcher-in-interaction. Beginning with the concept of a decentered (self- observation we develop the idea of the reflexive nature that relates the epistemic subject and object. We propose a way systematizing methodological considerations and procedures that follows the research process, beginning with the identification of a research topic to the final presentation of the results. The contributions to the two present FQS volumes on "Subjectivity and Reflexivity in Qualitative Research" provide answers and possible solutions to the questions and problems raised in this introduction. URN: urn:nbn:de:0114-fqs0302258

Comparison between the effects of lisinopril and losartan on the cougn reflex in anesthetized and awake rabbits.

Science.gov (United States)

Mutolo, D; Cinelli, E; Bongianni, F; Evangelista, S; Pantaleo, T

2013-04-01

The aim of the present study was to analyze differences in cough induction between losartan and lisinopril in both anaesthetized and awake rabbits, i.e., under conditions in which the influences of higher brain areas on the cough reflex are strongly reduced or abolished. Losartan (500 μg/kg), lisinopril (100 μg/kg) and NaCl 0.9% saline solution (vehicle) were administered by intravenous injections. Animals were randomly assigned to the different experimental treatments. The cough reflex was induced by chemical (citric acid) and/or mechanical stimulation of the tracheobronchial tree. In anaesthetized rabbits, losartan and lisinopril caused similar hypotensive effects. Lisinopril, but not losartan, increased the cough response induced by both mechanical and chemical stimulation due to increases in the cough number, i.e. the number of coughs induced by each stimulation challenge. In awake animals, only lisinopril significantly increased the cough number. The results support the notion that cough potentiation induced by losartan, and possibly other sartans, is lower than that induced by most angiotensin-converting enzyme inhibitors despite the reduction or complete absence of higher brain functions. In this connection, the comparison between present results and our previous findings on ramipril and zofenopril shows that losartan and zofenopril display similar cough-inducing potency, much lower than that of lisinopril and ramipril.

Transient receptor potential A1 channel contributes to activation of the muscle reflex.

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Koba, Satoshi; Hayes, Shawn G; Sinoway, Lawrence I

2011-01-01

This study was undertaken to elucidate the role played by transient receptor potential A1 channels (TRPA1) in activating the muscle reflex, a sympathoexcitatory drive originating in contracting muscle. First, we tested the hypothesis that stimulation of the TRPA1 located on muscle afferents reflexly increases sympathetic nerve activity. In decerebrate rats, allyl isothiocyanate, a TRPA1 agonist, was injected intra-arterially into the hindlimb muscle circulation. This led to a 33% increase in renal sympathetic nerve activity (RSNA). The effect of allyl isothiocyanate was a reflex because the response was prevented by sectioning the sciatic nerve. Second, we tested the hypothesis that blockade of TRPA1 reduces RSNA response to contraction. Thirty-second continuous static contraction of the hindlimb muscles, induced by electrical stimulation of the peripheral cut ends of L(4) and L(5) ventral roots, increased RSNA and blood pressure. The integrated RSNA during contraction was reduced by HC-030031, a TRPA1 antagonist, injected intra-arterially (163 ± 24 vs. 95 ± 21 arbitrary units, before vs. after HC-030031, P reflex. Increases in RSNA in response to injection into the muscle circulation of arachidonic acid, bradykinin, and diprotonated phosphate, which are metabolic by-products of contraction and stimulants of muscle afferents during contraction, were reduced by HC-030031. These observations suggest that the TRPA1 located on muscle afferents is part of the muscle reflex and further support the notion that arachidonic acid metabolites, bradykinin, and diprotonated phosphate are candidates for endogenous agonists of TRPA1.

Reflexive intergroup bias in third-party punishment.

Science.gov (United States)

Yudkin, Daniel A; Rothmund, Tobias; Twardawski, Mathias; Thalla, Natasha; Van Bavel, Jay J

2016-11-01

Humans show a rare tendency to punish norm-violators who have not harmed them directly-a behavior known as third-party punishment. Research has found that third-party punishment is subject to intergroup bias, whereby people punish members of the out-group more severely than the in-group. Although the prevalence of this behavior is well-documented, the psychological processes underlying it remain largely unexplored. Some work suggests that it stems from people's inherent predisposition to form alliances with in-group members and aggress against out-group members. This implies that people will show reflexive intergroup bias in third-party punishment, favoring in-group over out-group members especially when their capacity for deliberation is impaired. Here we test this hypothesis directly, examining whether intergroup bias in third-party punishment emerges from reflexive, as opposed to deliberative, components of moral cognition. In 3 experiments, utilizing a simulated economic game, we varied participants' group relationship to a transgressor, measured or manipulated the extent to which they relied on reflexive or deliberative judgment, and observed people's punishment decisions. Across group-membership manipulations (American football teams, nationalities, and baseball teams) and 2 assessments of reflexive judgment (response time and cognitive load), reflexive judgment heightened intergroup bias, suggesting that such bias in punishment is inherent to human moral cognition. We discuss the implications of these studies for theories of punishment, cooperation, social behavior, and legal practice. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Acute anal stretch inhibits NMDA-dependent pelvic-urethra reflex potentiation via spinal GABAergic inhibition in anesthetized rats.

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Chen, Sung-Lang; Huang, Yu-Hui; Kao, Yu-Lin; Chen, Gin-Den; Cheng, Chen-Li; Peng, Hsien-Yu; Liao, Jiuan-Miaw; Huang, Pei-Chen; Tsai, Shih-Jei; Lin, Tzer-Bin

2008-10-01

The impact of acute anal stretch on the pelvic-urethra reflex potentiation was examined in urethane-anesthetized rats by recording the external urethra sphincter electromyogram activity evoked by the pelvic afferent stimulation. Test stimulation (1 stimulation/30 s) evoked a baseline reflex activity with a single action potential that was abolished by gallamine (5 mg/kg iv). On the other hand, the repetitive stimulation (1 stimulation/1 s) induced spinal reflex potentiation (SRP) that was attenuated by intrathecal 6-cyano-7-nitroquinoxaline-2,4-dione (a glutamatergic alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionat receptor antagonist, 100 microM, 10 microl) and d-2-amino-5-phosphonovalerate [a glutamatergic N-methyl-D-aspartate (NMDA) antagonist, 100 microM, 10 microl]. Acute anal stretch using a mosquito clamp with a distance of 4 mm exhibited no effect, whereas distances of 8 mm attenuated and 12 mm abolished the repetitive stimulation-induced SRP. Intrathecal NMDA (100 microM, 10 microl) reversed the abolition on SRP caused by anal stretch. On the other hand, pretreated bicuculline [gamma-aminobutyric acid (GABA) A receptor antagonist, 100 microM, 10 microl] but not hydroxysaclofen (GABAB receptor antagonist) counteracted the abolition on the repetitive stimulation-induced SRP caused by the anal stretch. All of the results suggested that anal stretch may be used as an adjunct to assist voiding dysfunction in patients with overactive urethra sphincter and that GABAergic neurotransmission is important in the neural mechanisms underlying external urethra sphincter activity inhibited by anal stretch.

Local Injections of Superoxide Dismutase Attenuate the Exercise Pressor Reflex in Rats with Femoral Artery Occlusion

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Jihong Xing

2018-02-01

Full Text Available The exercise pressor reflex is amplified in patients with peripheral artery disease (PAD and in an experimental PAD model of rats induced by femoral artery occlusion. Heightened blood pressure worsens the restricted blood flow directed to the limbs in this disease. The purpose of this study was to determine the role played by muscle oxidative stress in regulating the augmented pressor response to static exercise in PAD. We hypothesized that limb ischemia impairs muscle superoxide dismutase (SOD thereby leading to abnormal autonomic responsiveness observed in PAD animals, and a chronic compensation of SOD for anti-oxidation improves the exaggerated exercise pressor reflex. Our data show that femoral occlusion decreased the protein levels of SOD in ischemic muscle as compared with control muscle. Downregulation of SOD appeared to a greater degree in the oxidative (red muscle than in the glycolytic (white muscle under the condition of muscle ischemia. In addition, the exercise pressor response was assessed during electrically induced static contraction. The data demonstrates that the enhancement of the exercise pressor reflex was significantly attenuated after tempol (a mimetic of SOD, 30 mg over a period of 72 h was administered into the occluded hindlimb. In the occluded rats, mean arterial pressure (MAP response was 26 ± 3 mmHg with no tempol and 12 ± 2 mmHg with tempol application (P < 0.05 vs. group with no tempol; n = 6 in each group. There were no differences in muscle tension development (time-tension index: 12.1 ± 1.2 kgs with no tempol and 13.5 ± 1.1 kgs with tempol; P > 0.05 between groups. In conclusion, SOD is lessened in the ischemic muscles and supplement of SOD improves the amplified exercise pressor reflex, which is likely beneficial to the restricted blood flow to the limbs in PAD.

Snout and Visual Rooting Reflexes in Infantile Autism. Brief Report.

Science.gov (United States)

Minderaa, Ruud B.; And Others

1985-01-01

The authors conducted extensive neurological evaluations of 42 autistic individuals and were surprised to discover a consistently positive snout reflex in most of them. Difficulties with assessing the reflex are noted. The authors then reassessed the Ss for a series of primitive reflexes which are interpreted as signs of diffuse cortical brain…

The influence of reflexive educational environment on students ...

African Journals Online (AJOL)

The influence of reflexive educational environment on students' reflection development in ... based on them) from which, as they integrate, a reflexive personality style is developed. ... (narrative, dialogical, cognitive and axiological) are the factors influencing the outcome of social adaptation. ... AJOL African Journals Online.

Somatic modulation of spinal reflex bladder activity mediated by nociceptive bladder afferent nerve fibers in cats.

Science.gov (United States)

Xiao, Zhiying; Rogers, Marc J; Shen, Bing; Wang, Jicheng; Schwen, Zeyad; Roppolo, James R; de Groat, William C; Tai, Changfeng

2014-09-15

The goal of the present study was to determine if supraspinal pathways are necessary for inhibition of bladder reflex activity induced by activation of somatic afferents in the pudendal or tibial nerve. Cats anesthetized with α-chloralose were studied after acute spinal cord transection at the thoracic T9/T10 level. Dilute (0.25%) acetic acid was used to irritate the bladder, activate nociceptive afferent C-fibers, and trigger spinal reflex bladder contractions (amplitude: 19.3 ± 2.9 cmH2O). Hexamethonium (a ganglionic blocker, intravenously) significantly (P reflex bladder contractions to 8.5 ± 1.9 cmH2O. Injection of lidocaine (2%, 1-2 ml) into the sacral spinal cord or transection of the sacral spinal roots and spinal cord further reduced the contraction amplitude to 4.2 ± 1.3 cmH2O. Pudendal nerve stimulation (PNS) at frequencies of 0.5-5 Hz and 40 Hz but not at 10-20 Hz inhibited reflex bladder contractions, whereas tibial nerve stimulation (TNS) failed to inhibit bladder contractions at all tested frequencies (0.5-40 Hz). These results indicate that PNS inhibition of nociceptive afferent C-fiber-mediated spinal reflex bladder contractions can occur at the spinal level in the absence of supraspinal pathways, but TNS inhibition requires supraspinal pathways. In addition, this study shows, for the first time, that after acute spinal cord transection reflex bladder contractions can be triggered by activating nociceptive bladder afferent C-fibers using acetic acid irritation. Understanding the sites of action for PNS or TNS inhibition is important for the clinical application of pudendal or tibial neuromodulation to treat bladder dysfunctions. Copyright © 2014 the American Physiological Society.

Orientation dependence of stress-induced martensite formation during nanoindentation in NiTi shape memory alloys

International Nuclear Information System (INIS)

Laplanche, G.; Pfetzing-Micklich, J.; Eggeler, G.

2014-01-01

In the present work we used nanoindentation with a spherical indenter tip to study the formation of stress-induced martensite in NiTi shape memory alloys. Prior to nanoindentation, orientation imaging was performed to select austenite grains with specific crystallographic orientations, including the principal crystallographic directions [0 0 1], [1 0 1] and [1 1 1]. We studied a material where stress-induced martensite is stable at room temperature and found surface patterns with four-, two- and threefold symmetries for the [0 0 1], [1 0 1] and [1 1 1] crystallographic indentation directions, respectively. Atomic force microscopy investigations of the topography showed that the surface patterns were associated with sink-ins. The crystallographic sink-in patterns disappeared during heating, which proved their martensitic origin. Our results provide clear experimental evidence which shows that the crystallographic anisotropy of nanoindentation is governed by the crystallographic anisotropy of the stress-induced formation of martensite

[Human physiology: images and practices of the reflex].

Science.gov (United States)

Wübben, Yvonne

2010-01-01

The essay examines the function of visualizations and practices in the formation of the reflex concept from Thomas Willis to Marshall Hall. It focuses on the specific form of reflex knowledge that images and practices can contain. In addition, the essay argues that it is through visual representations and experimental practices that technical knowledge is transferred to the field of human reflex physiology. When using technical metaphors in human physiology authors often seem to feel obliged to draw distinctions between humans, machines and animals. On closer scrutiny, these distinctions sometimes fail to establish firm borders between the human and the technical.

Effects of coil orientation on the electric field induced by TMS over the hand motor area

International Nuclear Information System (INIS)

Laakso, Ilkka; Hirata, Akimasa; Ugawa, Yoshikazu

2014-01-01

Responses elicited by transcranial magnetic stimulation (TMS) over the hand motor area depend on the position and orientation of the stimulating coil. In this work, we computationally investigate the induced electric field for multiple coil orientations and locations in order to determine which parts of the brain are affected and how the sensitivity of motor cortical activation depends on the direction of the electric field. The finite element method is used for calculating the electric field induced by TMS in two individual anatomical models of the head and brain. The orientation of the coil affects both the strength and depth of penetration of the electric field, and the field strongly depends on the direction of the sulcus, where the target neurons are located. The coil position that gives the strongest electric field in the target cortical region may deviate from the closest scalp location by a distance on the order of 1 cm. Together with previous experimental data, the results support the hypothesis that the cortex is most sensitive to fields oriented perpendicular to the cortical layers, while it is relatively insensitive to fields parallel to them. This has important implications for targeting of TMS. To determine the most effective coil position and orientation, it is essential to consider both biological (the direction of the targeted axons) and physical factors (the strength and direction of the electric field). (paper)

Simultaneous characterizations of reflex and nonreflex dynamic and static changes in spastic hemiparesis

Science.gov (United States)

Chung, Sun G.; Ren, Yupeng; Liu, Lin; Roth, Elliot J.; Rymer, W. Zev

2013-01-01

This study characterizes tonic and phasic stretch reflex and stiffness and viscosity changes associated with spastic hemiparesis. Perturbations were applied to the ankle of 27 hemiparetic and 36 healthy subjects under relaxed or active contracting conditions. A nonlinear delay differential equation model characterized phasic and tonic stretch reflex gains, elastic stiffness, and viscous damping. Tendon reflex was characterized with reflex gain and threshold. Reflexively, tonic reflex gain was increased in spastic ankles at rest (P hemiparesis may help to evaluate and treat them more effectively. PMID:23636726

Correlation of augmented startle reflex with brainstem electrophysiological responses in Tay-Sachs disease.

Science.gov (United States)

Nakamura, Sadao; Saito, Yoshiaki; Ishiyama, Akihiko; Sugai, Kenji; Iso, Takashi; Inagaki, Masumi; Sasaki, Masayuki

2015-01-01

To clarify the evolution of an augmented startle reflex in Tay-Sachs disease and compare the temporal relationship between this reflex and brainstem evoked potentials. Clinical and electrophysiological data from 3 patients with Tay-Sachs disease were retrospectively collected. The augmented startle reflex appeared between the age of 3 and 17 months and disappeared between the age of 4 and 6 years. Analysis of brainstem auditory evoked potentials revealed that poor segregation of peak I, but not peak III, coincided with the disappearance of the augmented startle reflex. A blink reflex with markedly high amplitude was observed in a patient with an augmented startle reflex. The correlation between the augmented startle reflex and the preservation of peak I but not peak III supports the theory that the superior olivary nucleus is dispensable for this reflex. The blink reflex with high amplitudes may represent augmented excitability of reticular formation at the pontine tegmentum in Tay-Sachs disease, where the pattern generators for the augmented startle and blink reflexes may functionally overlap. Copyright © 2014 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Student Mobility and Transnational Social Ties as Factors of Reflexivity

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Tea Golob

2018-03-01

Full Text Available The article seeks to develop and apply new quantitative measurement instruments capable of significantly improving understanding of the relationship between the transnational mobility and transnational social ties of students, along with their reflexive capacities. With a focus on students building their personal networks, educational and professional activities that extend beyond the nation’s borders and organising their day-to-day routines in transnational social spaces, we analyse the role of mobility in their reflexive capacities. Applying a tool that is line with Archer’s theory and indicators to measure reflexivity, and transnational social ties as proposed by Molina et al., we analyse data collected via an on-line survey questionnaire administered to Slovenian students. In addition, students from the Middle East (Lebanon and the USA (Hawai’i are added for comparative purposes. The results of path analysis show the Slovenian students’ mobility as such implies higher scores for meta reflexivity, combined with lower scores for communicative and fractured reflexivity. Further, social transactions reaching beyond one’s physical localities in terms of transnational social ties implies they have higher levels of reflexivity in general.

Desensitization of the cough reflex by exercise and voluntary isocapnic hyperpnea.

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Lavorini, Federico; Fontana, Giovanni A; Chellini, Elisa; Magni, Chiara; Duranti, Roberto; Widdicombe, John

2010-05-01

Little is known about the effects of exercise on the sensory and cognitive aspects of coughing evoked by inhalation of tussigenic agents. The threshold for the cough reflex induced by inhalation of increasing nebulizer outputs of ultrasonically nebulized distilled water (fog), an index of cough reflex sensitivity, was assessed in twelve healthy humans in control conditions, during exercise and during voluntary isocapnic hyperpnea (VIH) at the same ventilatory level as the exercise. The intensity of the urge to cough (UTC), a cognitive component of coughing, was recorded throughout the trials on a linear scale. The relationships between inhaled fog nebulizer outputs and the correspondingly evoked UTC values, an index of the perceptual magnitude of the UTC sensitivity, were also calculated. Cough appearance was always assessed audiovisually. At an exercise level of 80% of anaerobic threshold, the median cough threshold was increased from a control value of 0.73 to 2.22 ml/min (PVIH, the threshold increased from 0.73 to 2.22 ml/min (PVIH compared with control, mean UTC values at cough threshold were unchanged, i.e., control, 3.83 cm; exercise, 3.12 cm; VIH, 4.08 cm. The relationship of the fog nebulizer output/UTC value was linear in control conditions and logarithmic during both exercise and VIH. The perception of the magnitude of the UTC seems to be influenced by signals or sensations arising from exercising limb and thoracic muscles and/or by higher nervous (cortical) mechanisms. The results indicate that the adjustments brought into action by exercise-induced or voluntary hyperpnea exert inhibitory influences on the sensory and cognitive components of fog-induced cough.

Adaptive behavior of neighboring neurons during adaptation-induced plasticity of orientation tuning in V1

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Shumikhina Svetlana

2009-12-01

Full Text Available Abstract Background Sensory neurons display transient changes of their response properties following prolonged exposure to an appropriate stimulus (adaptation. In adult cat primary visual cortex, orientation-selective neurons shift their preferred orientation after being adapted to a non-preferred orientation. The direction of those shifts, towards (attractive or away (repulsive from the adapter depends mostly on adaptation duration. How the adaptive behavior of a neuron is related to that of its neighbors remains unclear. Results Here we show that in most cases (75%, cells shift their preferred orientation in the same direction as their neighbors. We also found that cells shifting preferred orientation differently from their neighbors (25% display three interesting properties: (i larger variance of absolute shift amplitude, (ii wider tuning bandwidth and (iii larger range of preferred orientations among the cluster of cells. Several response properties of V1 neurons depend on their location within the cortical orientation map. Our results suggest that recording sites with both attractive and repulsive shifts following adaptation may be located in close proximity to iso-orientation domain boundaries or pinwheel centers. Indeed, those regions have a more diverse orientation distribution of local inputs that could account for the three properties above. On the other hand, sites with all cells shifting their preferred orientation in the same direction could be located within iso-orientation domains. Conclusions Our results suggest that the direction and amplitude of orientation preference shifts in V1 depend on location within the orientation map. This anisotropy of adaptation-induced plasticity, comparable to that of the visual cortex itself, could have important implications for our understanding of visual adaptation at the psychophysical level.

GABA in nucleus tractus solitarius participates in electroacupuncture modulation of cardiopulmonary bradycardia reflex.

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Tjen-A-Looi, Stephanie C; Guo, Zhi-Ling; Longhurst, John C

2014-12-01

Phenylbiguanide (PBG) stimulates cardiopulmonary receptors and cardiovascular reflex responses, including decreases in blood pressure and heart rate mediated by the brain stem parasympathetic cardiac neurons in the nucleus ambiguus and nucleus tractus solitarius (NTS). Electroacupuncture (EA) at P5-6 stimulates sensory fibers in the median nerve and modulates these reflex responses. Stimulation of median nerves reverses bradycardia through action of γ-aminobutyric acid (GABA) in the nucleus ambiguus, important in the regulation of heart rate. We do not know whether the NTS or the neurotransmitter mechanisms in this nucleus participate in these modulatory actions by acupuncture. We hypothesized that somatic nerve stimulation during EA (P5-6) modulates cardiopulmonary inhibitory responses through a GABAergic mechanism in the NTS. Anesthetized and ventilated cats were examined during either PBG or direct vagal afferent stimulation while 30 min of EA was applied at P5-6. Reflex heart rate and blood pressure responses and NTS-evoked discharge were recorded. EA reduced the PBG-induced depressor and bradycardia reflexes by 67% and 60%, respectively. Blockade of GABAA receptors in the NTS reversed EA modulation of bradycardia but not the depressor response. During EA, gabazine reversed the vagally evoked discharge activity of cardiovascular NTS neurons. EA modulated the vagal-evoked cardiovascular NTS cellular activity for 60 min. Immunohistochemistry using triple labeling showed GABA immunoreactive fibers juxtaposed to glutamatergic nucleus ambiguus-projecting NTS neurons in rats. These glutamatergic neurons expressed GABAA receptors. These findings suggest that EA inhibits PBG-evoked bradycardia and vagally evoked NTS activity through a GABAergic mechanism, likely involving glutamatergic nucleus ambiguus-projecting NTS neurons. Copyright © 2014 the American Physiological Society.

Primitive reflexes and cognitive function Reflexos primitivos e função cognitiva

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Alfredo Damasceno

2005-09-01

Full Text Available BACKGROUND: Data on the prevalence of primitive reflexes (PR in adulthood, their pathological significance and relationship to age and cognition are controversial. OBJECTIVE: To study the relationship between PR and cognition in 30 patients with probable Alzheimer's disease (AD and 154 control subjects. METHOD: Diagnosis of probable AD was based on DSM-IV, NINCDS-ADRDA, and CAMDEX criteria. Primitive reflexes were quantified from zero (absent to 1 (mild or 2 (markedly present. The Cognitive Abilities Screening Instrument - Short Form (CASI-S was used to evaluate registration, temporal orientation, verbal fluency and recall. A drawing test was added. RESULTS: Most frequent PR among demented and controls were suck (77% and 62%, respectively and snout (60% and 27%, followed by glabellar (30% and 19%, paratonia (37% and 5%, and palmomental (23% and 5%. None of controls had more than three PR. Frequency of PR tended to increase with age and cognitive deterioration. Grasp and Babinski responses were found only in dementia patients. Primitive reflexes were not correlated with each other, except snout with suck, and snout with glabellar reflex. CONCLUSION: The finding of grasp and Babinski sign, or the presence of more than three primitive signs, particularly the combination of paratonia, snout, suck, and palmomental reflexes strongly suggests brain dysfunction, especially when these signs are marked and accompanied by deficits in orientation, recall, verbal fluency, and constructional praxis.CONTEXTO: A prevalência e significado patológico dos reflexos primitivos (RP no adulto, bem como sua relação com a idade e a cognição, são questões controversas. OBJETIVO: Estudar a relação entre RP e cognição em 30 pacientes com doença de Alzheimer (DA e 154 sujeitos controles normais. MÉTODO: O diagnóstico de DA baseou-se nos critérios DSM-IV, NINCDS-ADRDA e CAMDEX. Os RP foram quantificados de 0 (ausente a 1 (leve ou 2 (acentuado. CASI

Reflexivity: The Creation of Liminal Spaces--Researchers, Participants, and Research Encounters.

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Enosh, Guy; Ben-Ari, Adital

2016-03-01

Reflexivity is defined as the constant movement between being in the phenomenon and stepping outside of it. In this article, we specify three foci of reflexivity--the researcher, the participant, and the encounter--for exploring the interview process as a dialogic liminal space of mutual reflection between researcher and participant. Whereas researchers' reflexivity has been discussed extensively in the professional discourse, participants' reflexivity has not received adequate scholarly attention, nor has the promise inherent in reflective processes occurring within the encounter. © The Author(s) 2015.

Probabilities on Streams and Reflexive Games

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Andrew Schumann

2014-01-01

Full Text Available Probability measures on streams (e.g. on hypernumbers and p-adic numbers have been defined. It was shown that these probabilities can be used for simulations of reflexive games. In particular, it can be proved that Aumann's agreement theorem does not hold for these probabilities. Instead of this theorem, there is a statement that is called the reflexion disagreement theorem. Based on this theorem, probabilistic and knowledge conditions can be defined for reflexive games at various reflexion levels up to the infinite level. (original abstract

Researching Reflexively With Patients and Families: Two Studies Using Video-Reflexive Ethnography to Collaborate With Patients and Families in Patient Safety Research.

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Collier, Aileen; Wyer, Mary

2016-06-01

Patient safety research has to date offered few opportunities for patients and families to be actively involved in the research process. This article describes our collaboration with patients and families in two separate studies, involving end-of-life care and infection control in acute care. We used the collaborative methodology of video-reflexive ethnography, which has been primarily used with clinicians, to involve patients and families as active participants and collaborators in our research. The purpose of this article is to share our experiences and findings that iterative researcher reflexivity in the field was critical to the progress and success of each study. We present and analyze the complexities of reflexivity-in-the-field through a framework of multilayered reflexivity. We share our lessons here for other researchers seeking to actively involve patients and families in patient safety research using collaborative visual methods. © The Author(s) 2015.

Learning reflexively from a health promotion professional development program in Canada.

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Tremblay, Marie-Claude; Richard, Lucie; Brousselle, Astrid; Beaudet, Nicole

2014-09-01

In recent decades, reflexivity has received much attention in the professional education and training literature, especially in the public health and health promotion fields. Despite general agreement on the importance of reflexivity, there appears to be no consensus on how to assess reflexivity or to conceptualize the different forms developed among professionals and participants of training programs. This paper presents an analysis of the reflexivity outcomes of the Health Promotion Laboratory, an innovative professional development program aimed at supporting practice changes among health professionals by fostering competency development and reflexivity. More specifically, this paper explores the difference between two levels of reflexivity (formative and critical) and highlights some implications of each for practice. Data were collected through qualitative interviews with participants from two intervention sites. Results showed that involvement in the Health Promotion Laboratory prompted many participants to modify their vision of their practice and professional role, indicating an impact on reflexivity. In many cases, new understandings seem to have played a formative function in enabling participants to improve their practice and their role as health promoters. The reflective process also served a critical function culminating in a social and moral understanding of the impacts on society of the professionals' practices and roles. This type of outcome is greatly desired in health promotion, given the social justice and equity concerns of this field of practice. By redefining the theoretical concept of reflexivity on two levels and discussing their impacts on practice, this study supports the usefulness of both levels of reflexivity. © The Author (2013). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Study of Achilles Tendon Reflex in Normal Korean and Various Thyroid Diseases

International Nuclear Information System (INIS)

Kang, Jin Yung; Kim, Kwang Won; Yae, Sung Bo; Lee, Hong Kyu; Koh, Chang Soon

1975-01-01

In an attempt to establish the diagnostic value of Achilles tendon reflex and to determine the normal value of Achilles tendon reflex time in normal Korean, the author measured the Achilles tendon reflex time by photomotograph. This study was carried out in 272 cases with various thyroid diseases and 340 normal Korean. 1) The Achilles tendon reflex time in normal Korean was like this, between 11 years old and 20 years old; male (62 cases); 250±27 msec, female (36 cases); 266±27 msec, between 21 years old and 30 years old; male (38 cases); 271±27 msec, female (21 cases); 284±27 msec, between 31 years old and 40 years old; male (26 cases); 275±25 msec, female (29 cases); 291±27 msec, between 41 years old and 50 years old; male (20 cases); 286±35 msec, female (24 cases); 307±42 msec, between 51 years old and 60 years old, male (20 cases); 296±33 msec, female (20 cases); 318±46 msec, over 61 years; male (24 cases) 301±33 msec, female (20 cases); 325±35 msec. The Achilles tendon reflex time was delayed with increasing age and delayed in the female. 2) The Achilles tendon reflex time was markedly shortened to 221±20 msec in untreated hyperthyroidism. 3) The Achilles tendon reflex time was markedly delayed to 435±59 msec in hypothyroidism. 4) The Achilles tendon reflex time was not changed significantly in other thyroid diseases with norms thyroid function. 5) The Achilles tendon reflex time showed good correlationship with ETR, T 3 RU, 131 I thyroid uptake and serum TSH. 6) Reproducibility of Achilles tendon reflex time was good, and no significant difference between left and right was noted. 7) Diagnostic accuracy of Achilles tendon reflex time was 71% in hyperthyroidism and 90% in hypothyroidism. 8) The Achilles tendon reflex time showed useful test to evaluate the clinical course of the hyperthyroidism.

Maternal low-protein diet-induced delayed reflex ontogeny is attenuated by moderate physical training during gestation in rats.

Science.gov (United States)

Falcão-Tebas, Filippe; Bento-Santos, Adriano; Fidalgo, Marco Antônio; de Almeida, Marcelus Brito; dos Santos, José Antônio; Lopes de Souza, Sandra; Manhães-de-Castro, Raul; Leandro, Carol Góis

2012-02-01

We evaluated the effects of moderate- to low-intensity physical training during gestation on reflex ontogeny in neonate rats whose mothers were undernourished. Virgin female Wistar rats were divided into four groups as follows: untrained (NT, n 7); trained (T, n 7); untrained with a low-protein diet (NT+LP, n 7); trained with a low-protein diet (T+LP, n 4). Trained rats were subjected to a protocol of moderate physical training on a treadmill over a period of 4 weeks (5 d/week and 60 min/d, at 65 % of VO₂max). After confirming the pregnancy, the intensity and duration of the exercise were reduced. Low-protein groups were provided with an 8 % casein diet, and controls were provided with a 17 % casein diet. Their respective offspring were evaluated (during the 10th-17th days of postnatal life) in terms of physical feature maturation, somatic growth and reflex ontogeny. Pups born to mothers provided with the low-protein diet during gestation and lactation showed delayed physical feature and reflex maturation and a deficit in somatic growth when compared with controls. However, most of these deficiencies were attenuated in pups of undernourished mothers undergoing training. In conclusion, physical training during gestation attenuates the effects of perinatal undernutrition on some patterns of maturation in the central nervous system during development.

The inhibiting effect of dislocation helices on the stress-induced orientation of S' precipitates in Al–Cu–Mg alloy

Energy Technology Data Exchange (ETDEWEB)

Guo, Xiaobin [School of Materials Science and Engineering, Central South University, Changsha (China); Deng, Yunlai, E-mail: luckdeng@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha (China); State Key Laboratory of High Performance and Complex Manufacturing, Central South University, Changsha (China); Zhang, Jin [State Key Laboratory of High Performance and Complex Manufacturing, Central South University, Changsha (China); Light Alloy Research Institute, Central South University, Changsha (China); Zhang, Xinming [School of Materials Science and Engineering, Central South University, Changsha (China); State Key Laboratory of High Performance and Complex Manufacturing, Central South University, Changsha (China)

2015-09-15

The phenomenon of restrained stress-induced preferential orientation of S′ precipitates is investigated using a single-crystal of Al–1.23Cu–0.43 Mg alloy. Al–1.23Cu–0.43 Mg single-crystal specimens are subjected to stress aging, and the microstructure is analyzed by transmission electron microscopy (TEM). It is found that the stress-induced preferential orientation of S′ precipitates is restrained owing to the dislocations produced by a higher stress. The effect of dislocations on the oriented precipitates depends on the total length of the intersection lines for precipitate habit planes and dislocation glide planes. This investigation not only provides important insight into solving the anisotropy problem attributed to precipitation strengthening, but also offers a benchmark for choosing the appropriate stress range in manufacturing of Al–Cu–Mg alloys. - Highlights: • Single crystals of an Al–Cu–Mg alloy were prepared for the investigations. • A phenomenon of restrained stress-induced preferential orientation of S′ precipitates was found. • The influence of dislocation helices on precipitation during stress-aging was studied. • Difference of orientation degree of S′ precipitates and θ′ precipitates was explained. • A basis for choosing the appropriate stress range in manufacturing of Al–Cu–Mg alloys is provided.

Avian reflex and electroencephalogram responses in different states of consciousness.

Science.gov (United States)

Sandercock, Dale A; Auckburally, Adam; Flaherty, Derek; Sandilands, Victoria; McKeegan, Dorothy E F

2014-06-22

Defining states of clinical consciousness in animals is important in veterinary anaesthesia and in studies of euthanasia and welfare assessment at slaughter. The aim of this study was to validate readily observable reflex responses in relation to different conscious states, as confirmed by EEG analysis, in two species of birds under laboratory conditions (35-week-old layer hens (n=12) and 11-week-old turkeys (n=10)). We evaluated clinical reflexes and characterised electroencephalograph (EEG) activity (as a measure of brain function) using spectral analyses in four different clinical states of consciousness: conscious (fully awake), semi-conscious (sedated), unconscious-optimal (general anaesthesia), unconscious-sub optimal (deep hypnotic state), as well as assessment immediately following euthanasia. Jaw or neck muscle tone was the most reliable reflex measure distinguishing between conscious and unconscious states. Pupillary reflex was consistently observed until respiratory arrest. Nictitating membrane reflex persisted for a short time (power (PTOT) significantly increased, whereas median (F50) and spectral edge (F95) frequencies significantly decreased. This study demonstrates that EEG analysis can differentiate between clinical states (and loss of brain function at death) in birds and provides a unique integration of reflex responses and EEG activity. Copyright © 2014 Elsevier Inc. All rights reserved.

Intrapartum synthetic oxytocin reduce the expression of primitive reflexes associated with breastfeeding.

Science.gov (United States)

Marín Gabriel, Miguel A; Olza Fernández, Ibone; Malalana Martínez, Ana M; González Armengod, Carmen; Costarelli, Valeria; Millán Santos, Isabel; Fernández-Cañadas Morillo, Aurora; Pérez Riveiro, Pilar; López Sánchez, Francisco; García Murillo, Lourdes

2015-05-01

Several synthetic peptide manipulations during the time surrounding birth can alter the specific neurohormonal status in the newborn brain. This study is aimed at assessing whether intrapartum oxytocin administration has any effect on primitive neonatal reflexes and determining whether such an effect is dose-dependent. A cohort prospective study was conducted at a tertiary hospital. Mother-infant dyads who received intrapartum oxytocin (n=53) were compared with mother-infant dyads who did not receive intrapartum oxytocin (n=45). Primitive neonatal reflexes (endogenous, antigravity, motor, and rhythmic reflexes) were quantified by analyzing videotaped breastfeeding sessions in a biological nurturing position. Two observers blind to the group assignment and the oxytocin dose analyzed the videotapes and assesed the newborn's state of consciousness according to the Brazelton scale. The release of all rhythmic reflexes (p=0.01), the antigravity reflex (p=0.04), and total primitive neonatal reflexes (p=0.02) in the group exposed to oxytocin was lower than in the group not exposed to oxytocin. No correlations were observed between the dose of oxytocin administered and the percentage of primitive neonatal reflexes released (r=0.03; p=0.82). Intrapartum oxytocin administration might inhibit the expression of several primitive neonatal reflexes associated with breastfeeding. This correlation does not seem to be dose-dependent.

Effect of methysergide on pudendal inhibition of micturition reflex in cats.

Science.gov (United States)

Matsuta, Yosuke; Schwen, Zeyad; Mally, Abhijith D; Shen, Bing; Wang, Jicheng; Roppolo, James R; de Groat, William C; Tai, Changfeng

2013-09-01

The role of 5-HT2 and opioid receptors in pudendal inhibition of bladder activity induced by intravesical infusion of saline or 0.25% acetic acid (AA) was investigated in anesthetized cats using methysergide (a 5-HT2 receptor antagonist) and naloxone (an opioid receptor antagonist). AA irritated the bladder and significantly (Preflex bladder activity and interact with opioid mechanisms in micturition reflex pathway. Understanding neurotransmitter mechanisms underlying pudendal neuromodulation is important for the development of new treatments for bladder disorders. Copyright © 2013 Elsevier Inc. All rights reserved.

FEFsem neuronal response during combined volitional and reflexive pursuit.

Science.gov (United States)

Bakst, Leah; Fleuriet, Jérome; Mustari, Michael J

2017-05-01

Although much is known about volitional and reflexive smooth eye movements individually, much less is known about how they are coordinated. It is hypothesized that separate cortico-ponto-cerebellar loops subserve these different types of smooth eye movements. Specifically, the MT-MST-DLPN pathway is thought to be critical for ocular following eye movements, whereas the FEF-NRTP pathway is understood to be vital for volitional smooth pursuit. However, the role that these loops play in combined volitional and reflexive behavior is unknown. We used a large, textured background moving in conjunction with a small target spot to investigate the eye movements evoked by a combined volitional and reflexive pursuit task. We also assessed the activity of neurons in the smooth eye movement subregion of the frontal eye field (FEFsem). We hypothesized that the pursuit system would show less contribution from the volitional pathway in this task, owing to the increased involvement of the reflexive pathway. In accordance with this hypothesis, a majority of FEFsem neurons (63%) were less active during pursuit maintenance in a combined volitional and reflexive pursuit task than during purely volitional pursuit. Interestingly and surprisingly, the neuronal response to the addition of the large-field motion was highly correlated with the neuronal response to a target blink. This suggests that FEFsem neuronal responses to these different perturbations-whether the addition or subtraction of retinal input-may be related. We conjecture that these findings are due to changing weights of both the volitional and reflexive pathways, as well as retinal and extraretinal signals.

Reflexivity as a control factor of personal coping behavior

OpenAIRE

BEKHTER A.A.

2014-01-01

The article deals with the issue of coping behavior control. The author defines the criteria, levels and aspects of reflexivity within the framework of personal coping behavior. In conclusion the author describes the key facets of coping behavior control and how reflexivity affects them.

Isometric and Dynamic Control of Neck Muscles : Reflexive contributions and muscle synergies

NARCIS (Netherlands)

De Bruijn, E.

2014-01-01

It is well established that the central nervous system (CNS) stabilizes the head using reflexive feedback and cocontraction. The major reflexive pathways in the neck are through muscle spindles generating the cervicocollic reflex (CCR) and through the vestibular organ generating the vestibulocollic

Comparison of Stretch Reflex Torques in Ankle Dorsiflexors and Plantarflexors

National Research Council Canada - National Science Library

Tung, J

2001-01-01

...) ankle muscles, Pulse, step, and a combination of random perturbation and step inputs were used to identify the reflex and intrinsic contributions to the measured torque, TA reflex torques were very...

Changes in the anisotropy of oriented membrane dynamics induced by myelin basic protein

Energy Technology Data Exchange (ETDEWEB)

Natali, F. [OGG-INFM, Grenoble (France); Gliozzi, A.; Rolandi, R.; Relini, A. [Dipartimento di Fisica and Istituto Nazionale per la Fisica della Materia, Universita di Genova (Italy); Cavatorta, P.; Deriu, A. [Dipartimento di Fisica and Istituto Nazionale per la Fisica della Materia, Universita di Parma (Italy); Fasano, A. [Dipartimento di Biochimica e Biologia Molecolare, Universita di Bari (Italy); Riccio, P. [Dipartimento di Biologia D.B.A.F., Universita della Basilicata, Potenza (Italy)

2002-07-01

We report recent results showing the evidence of the effect induced by physiological amounts of myelin basic protein (MBP) on the dynamics of dimyristoyl L-a-phosphatidic acid (DMPA) membranes. Incoherent elastic neutron scattering scans, performed over a wide temperature range, have shown that the anisotropy of motions in oriented membranes is significantly enhanced by the presence of MBP. (orig.)

ESO Reflex: a graphical workflow engine for data reduction

Science.gov (United States)

Hook, Richard; Ullgrén, Marko; Romaniello, Martino; Maisala, Sami; Oittinen, Tero; Solin, Otto; Savolainen, Ville; Järveläinen, Pekka; Tyynelä, Jani; Péron, Michèle; Ballester, Pascal; Gabasch, Armin; Izzo, Carlo

ESO Reflex is a prototype software tool that provides a novel approach to astronomical data reduction by integrating a modern graphical workflow system (Taverna) with existing legacy data reduction algorithms. Most of the raw data produced by instruments at the ESO Very Large Telescope (VLT) in Chile are reduced using recipes. These are compiled C applications following an ESO standard and utilising routines provided by the Common Pipeline Library (CPL). Currently these are run in batch mode as part of the data flow system to generate the input to the ESO/VLT quality control process and are also exported for use offline. ESO Reflex can invoke CPL-based recipes in a flexible way through a general purpose graphical interface. ESO Reflex is based on the Taverna system that was originally developed within the UK life-sciences community. Workflows have been created so far for three VLT/VLTI instruments, and the GUI allows the user to make changes to these or create workflows of their own. Python scripts or IDL procedures can be easily brought into workflows and a variety of visualisation and display options, including custom product inspection and validation steps, are available. Taverna is intended for use with web services and experiments using ESO Reflex to access Virtual Observatory web services have been successfully performed. ESO Reflex is the main product developed by Sampo, a project led by ESO and conducted by a software development team from Finland as an in-kind contribution to joining ESO. The goal was to look into the needs of the ESO community in the area of data reduction environments and to create pilot software products that illustrate critical steps along the road to a new system. Sampo concluded early in 2008. This contribution will describe ESO Reflex and show several examples of its use both locally and using Virtual Observatory remote web services. ESO Reflex is expected to be released to the community in early 2009.

Influence of crystal orientation on the formation of femtosecond laser-induced periodic surface structures and lattice defects accumulation

Energy Technology Data Exchange (ETDEWEB)

Sedao, Xxx; Garrelie, Florence, E-mail: florence.garrelie@univ-st-etienne.fr; Colombier, Jean-Philippe; Reynaud, Stéphanie; Pigeon, Florent [Université de Lyon, CNRS, UMR5516, Laboratoire Hubert Curien, Université de Saint Etienne, Jean Monnet, F-42023 Saint-Etienne (France); Maurice, Claire; Quey, Romain [Ecole Nationale Supérieure des Mines de Saint-Etienne, CNRS, UMR5307, Laboratoire Georges Friedel, F-42023 Saint-Etienne (France)

2014-04-28

The influence of crystal orientation on the formation of femtosecond laser-induced periodic surface structures (LIPSS) has been investigated on a polycrystalline nickel sample. Electron Backscatter Diffraction characterization has been exploited to provide structural information within the laser spot on irradiated samples to determine the dependence of LIPSS formation and lattice defects (stacking faults, twins, dislocations) upon the crystal orientation. Significant differences are observed at low-to-medium number of laser pulses, outstandingly for (111)-oriented surface which favors lattice defects formation rather than LIPSS formation.

Reflexive Dressing: Rethinking Retro

Directory of Open Access Journals (Sweden)

Stella North

2016-03-01

Full Text Available This article undertakes a philosophical exploration of the act we know, or think we know, as ‘dressing’. Inhabiting, in thought, the moment in which we dress, I examine some of its constituent mechanisms, attending to the impulses by which dressing is generated out of subjective experience.  When those impulses are temporally marked, as they are in the case of retro dress, this generation is a two-pronged process, in which the holding of the body in time, and the holding of time in the body, recalibrate one another. The process of ‘dressing,’ in this understanding, has a reflexivity which is double; it entails the turning of the body, with dress as medium, towards itself, and the turning of present experience towards some felt notion of the past. Reflexively dressing, we are always becoming ourselves, and becoming other than ourselves, at once; a movement of circuitous internalisation and externalisation by which the ambiguation inherent in material experience is realised.

Reflexive anaphor resolution in spoken language comprehension: Structural constraints and beyond

Directory of Open Access Journals (Sweden)

Kaili eClackson

2014-08-01

Full Text Available We report results from an eye-tracking during listening study examining English-speaking adults’ online processing of reflexive pronouns, and specifically whether the search for an antecedent is restricted to syntactically appropriate positions. Participants listened to a short story where the recipient of an object was introduced with a reflexive, and were asked to identify the object recipient as quickly as possible. This allowed for the recording of participants’ offline interpretation of the reflexive, response times, and eye movements on hearing the reflexive. Whilst our offline results show that the ultimate interpretation for reflexives was constrained by binding principles, the response time and eye-movement data revealed that during processing participants were temporarily distracted by a structurally inappropriate competitor antecedent when this was prominent in the discourse. These results indicate that in addition to binding principles, online referential decisions are also affected by discourse-level information.

Reflexive anaphor resolution in spoken language comprehension: structural constraints and beyond

Science.gov (United States)

Clackson, Kaili; Heyer, Vera

2014-01-01

We report results from an eye-tracking during listening study examining English-speaking adults’ online processing of reflexive pronouns, and specifically whether the search for an antecedent is restricted to syntactically appropriate positions. Participants listened to a short story where the recipient of an object was introduced with a reflexive, and were asked to identify the object recipient as quickly as possible. This allowed for the recording of participants’ offline interpretation of the reflexive, response times, and eye movements on hearing the reflexive. Whilst our offline results show that the ultimate interpretation for reflexives was constrained by binding principles, the response time, and eye-movement data revealed that during processing participants were temporarily distracted by a structurally inappropriate competitor antecedent when this was prominent in the discourse. These results indicate that in addition to binding principles, online referential decisions are also affected by discourse-level information. PMID:25191290

Management of Reflex Anoxic Seizures

Directory of Open Access Journals (Sweden)

J Gordon Millichap

2013-10-01

Full Text Available Investigators at the Roald Dahl EEG Unit, Alder Hey Children’s NHS Foundation, Liverpool, UK, review the definition, pathophysiology, clinical presentation, and management of reflex anoxic seizures (RAS in children.

Linear time delay methods and stability analyses of the human spine. Effects of neuromuscular reflex response.

Science.gov (United States)

Franklin, Timothy C; Granata, Kevin P; Madigan, Michael L; Hendricks, Scott L

2008-08-01

Linear stability methods were applied to a biomechanical model of the human musculoskeletal spine to investigate effects of reflex gain and reflex delay on stability. Equations of motion represented a dynamic 18 degrees-of-freedom rigid-body model with time-delayed reflexes. Optimal muscle activation levels were identified by minimizing metabolic power with the constraints of equilibrium and stability with zero reflex time delay. Muscle activation levels and associated muscle forces were used to find the delay margin, i.e., the maximum reflex delay for which the system was stable. Results demonstrated that stiffness due to antagonistic co-contraction necessary for stability declined with increased proportional reflex gain. Reflex delay limited the maximum acceptable proportional reflex gain, i.e., long reflex delay required smaller maximum reflex gain to avoid instability. As differential reflex gain increased, there was a small increase in acceptable reflex delay. However, differential reflex gain with values near intrinsic damping caused the delay margin to approach zero. Forward-dynamic simulations of the fully nonlinear time-delayed system verified the linear results. The linear methods accurately found the delay margin below which the nonlinear system was asymptotically stable. These methods may aid future investigations in the role of reflexes in musculoskeletal stability.

A new hypothesis of cause of syncope: trigeminocardiac reflex during extraction of teeth.

Science.gov (United States)

Arakeri, Gururaj; Arali, Veena

2010-02-01

Transient Loss Of Consciousness (TLOC) or vasovagal syncope is well known phenomenon in dental/maxillofacial surgery. Despite considerable study of vasovagal syncope, its pathophysiology remains to be fully elucidated. After having encountered a case of trigeminocardiac reflex after extraction of maxillary first molar we observed and studied 400 extractions under local anesthesia to know the relation between trigeminocardiac reflex and syncope. We make hypothesis that trigeminocardiac reflex which is usually seen under general anesthesia when all sympathetic reflexes are blunted can also occur under local anesthesia during extractions of maxillary molars (dento-cardiac reflex) and mediate syncope.

High-power ion beam generation with an inverse reflex tetrode

International Nuclear Information System (INIS)

Pasour, J.A.; Mahaffey, R.A.; Golden, J.; Kapetanakos, C.A.

1980-01-01

A new reflexing-electron ion source is described. The device produces a unidirectional ion beam with relatively high efficiency even when the applied magnetic field exceeds the self-field. This new source operates at a low, constant impedance during much of the applied voltage pulse and is better matched to available high-power, low-impedance generators than previous reflexing-electron devices. Proton pulses with peak current approx.500 kA have been produced with the inverse reflex tetrode coupled to the Gamble II generator

The Role of Transformational Leadership in Enhancing Team Reflexivity

NARCIS (Netherlands)

M.C. Schippers (Michaéla); D.N. den Hartog (Deanne); P.L. Koopman (Paul); D.L. van Knippenberg (Daan)

2007-01-01

textabstractTeam reflexivity, or the extent to which teams reflect upon and modify their functioning, has been identified as a key factor in the effectiveness of work teams. As yet, however, little is known about the factors that play a role in enhancing team reflexivity, and it is thus important to

The role of transformational leadership in enhancing team reflexivity

NARCIS (Netherlands)

Schippers, M.C.; den Hartog, D.N.; Koopman, P.L.; van Knippenberg, D.

2008-01-01

Team reflexivity, or the extent to which teams reflect upon and modify their functioning, has been identified as a key factor in the effectiveness of work teams. As yet, however, little is known about the factors that play a role in enhancing team reflexivity, and it is thus important to develop

Proximally evoked soleus H-reflex to S1 nerve root stimulation in sensory neuronopathies (ganglionopathies).

Science.gov (United States)

Zhu, Dong-Qing; Zhu, Yu; Qiao, Kai; Zheng, Chao-Jun; Bradley, Scott; Weber, Robert; Chen, Xiang-Jun

2013-11-01

Sensory neuronopathy (SNN) mimics distal sensory axonopathy. The conventional H-reflex elicited by tibial nerve stimulation (tibial H-reflex) is usually abnormal in both conditions. We evaluated the proximally evoked soleus H-reflex in response to S1 nerve root stimulation (S1 foramen H-reflex) in SNN. Eleven patients with SNN and 6 with distal sensory axonopathy were studied. Tibial and S1 foramen H-reflexes were performed bilaterally in each patient. Tibial and S1 foramen H-reflexes were absent bilaterally in all patients with SNN. In the patients with distal sensory axonopathy, tibial H-reflexes were absent in 4 and demonstrated prolonged latencies in 2, but S1 foramen H-reflexes were normal. Characteristic absence of the H-reflex after both proximal and distal stimulation reflects primary loss of dorsal root ganglion (DRG) neurons and the distinct non-length-dependent impairment of sensory nerve fibers in SNN. Copyright © 2013 Wiley Periodicals, Inc.

Deprivation and Recovery of Sleep in Succession Enhances Reflexive Motor Behavior

OpenAIRE

Sprenger, Andreas; Weber, Frederik D.; Machner, Bjoern; Talamo, Silke; Scheffelmeier, Sabine; Bethke, Judith; Helmchen, Christoph; Gais, Steffen; Kimmig, Hubert; Born, Jan

2015-01-01

Sleep deprivation impairs inhibitory control over reflexive behavior, and this impairment is commonly assumed to dissipate after recovery sleep. Contrary to this belief, here we show that fast reflexive behaviors, when practiced during sleep deprivation, is consolidated across recovery sleep and, thereby, becomes preserved. As a model for the study of sleep effects on prefrontal cortex-mediated inhibitory control in humans, we examined reflexive saccadic eye movements (express saccades), as w...

Trigeminocardiac reflex during endoscopic juvenile nasopharyngeal angiofibroma surgery: an appraisal.

Science.gov (United States)

Sharma, Shilpee Bhatia; Janakiram, Trichy Narayanan; Baxi, Hina; Chinnasamy, Balamurugan

2017-07-01

Juvenile nasopharyngeal angiofibroma is a locally aggressive benign tumour which has propensity to erode the skull base. The tumour spreads along the pathways of least resistance and is in close proximity to the extracranial part of trigeminal nerve. Advancements in expanded approaches for endoscopic excision of tumours in infratemporal fossa and pterygopalatine fossa increase the vulnerability for the trigeminocardiac reflex. The manipulation of nerve and its branches during tumour dissection can lead to sensory stimulation and thus inciting the reflex. The aim of our study is to report the occurrence of trigeminocardiac reflex in endoscopic excision of juvenile nasopharyngeal angiofibroma. To describe the occurence of trigeminocardiac reflex during endoscopic endonasal excision of juvenile nasopharyngeal angiofibroma. We studied the occurrence of TCR in 15 patients (out of 242 primary cases and 52 revision cases) operated for endoscopic endonasal excision of JNA. The drop in mean arterial blood pressure and heart rate were observed and measured. To the best of our knowledge of English literature, this is the first case series reporting TCR as complication in endoscopic excision of JNA. occurence of this reflex has been mentioned in various occular, maxillofacial surgeries but its occurence during endoscopic excision of JNA has never been reported before. Manifestation of trigeminocardiac reflex during surgery can alter the course of the surgery and is a potential threat to life. It is essential for the anesthetist and surgeons to be familiar with the presentations, preventive measures and management protocols.

The role of TRPM8 in the Guinea-pig bladder-cooling reflex investigated using a novel TRPM8 antagonist.

Science.gov (United States)

Gardiner, Jennifer C; Kirkup, Anthony J; Curry, John; Humphreys, Sian; O'Regan, Paul; Postlethwaite, Michael; Young, Kimberley C; Kitching, Linda; Ethell, Brian T; Winpenny, David; McMurray, Gordon

2014-10-05

Patients with overactive bladder often exhibit abnormal bladder contractions in response to intravesical cold saline (positive ice-water test). The molecular entity involved in cold sensation within the urinary bladder is unknown, but a potential candidate is the ion channel, transient receptor potential (melastatin)-8 (TRPM8). The objective of the present study was to investigate the role of TRPM8 in a bladder-cooling reflex evoked in anaesthetised guinea-pigs that is comparable to the positive ice-water test seen in patients. Guinea-pig TRPM8 was cloned from L6 dorsal root ganglia (DRG) and expressed in HEK293 cells. Functional agonist- and cold-induced Ca2+ influx and electrophysiology assays were performed in these cells, and for comparison in HEK293 cells expressing human TRPM8, using a novel TRPM8 antagonist, the S-enantiomer of 1-phenylethyl 4-(benzyloxy)-3-methoxybenzyl (2-aminoethyl) carbamate hydrochloride (PBMC). Potency data from these assays was used to calculate intravenous infusion protocols for targeted plasma concentrations of PBMC in studies on micturition reflexes evoked by intravesical infusion of menthol or cold saline in anaesthetised guinea-pigs. Tissue expression of TRPM8 in guinea-pig bladder, urethra and in dorsal root ganglia neurones traced from the bladder was also investigated. TRPM8 mRNA and protein were detected in L6 dorsal root ganglia, bladder urothelium and smooth muscle. PBMC antagonised in vitro activation of human and guinea-pig TRPM8 and reversed menthol and cold-induced facilitation of the micturition reflex at plasma concentrations consistent with in vitro potencies. The present data suggest that the bladder-cooling reflex in the guinea-pig involves TRPM8. The potential significance of TRPM8 in bladder disease states deserves future investigation. Copyright © 2014 Elsevier B.V. All rights reserved.

Prenatal exposure to a low fipronil dose disturbs maternal behavior and reflex development in rats.

Science.gov (United States)

Udo, Mariana S B; Sandini, Thaísa M; Reis, Thiago M; Bernardi, Maria Martha; Spinosa, Helenice S

2014-01-01

Fipronil (FPN) is a phenylpyrazole insecticide used in veterinary services and agriculture, and it is of considerable concern to public health. It inhibits the chloride channels associated with gamma-amino butyric acid (GABA) receptors in mammals and also inhibits the chloride channels associated with GABA and glutamate (Glu) receptors in insects. In this study, a commercial product containing fipronil was orally administered to pregnant Wistar rats at dose levels of 0.1, 1.0, or 10.0mg/kg/day from the sixth to twentieth day of gestation (n=10 pregnant rats/group). Its toxicity was evaluated based on maternal toxicity, reproductive quality, maternal behavior, and offspring physical as well as reflex development. All parameters observed in the observed offspring were assigned to one ink-marked couple in each litter (n=20 animals/group - 10 males and 10 females). The offspring couple represented the litter. Slight maternal toxicity presented during the second week of gestation for each fipronil dose and during the third gestational week at the highest dose due to lower chow intake. However, no effects were observed for gestational weight gain or gestation time, and the reproductive quality was not impaired, which suggests no adverse maternal effects from the doses during pregnancy. Moreover, the lowest fipronil dose compromised the active and reflexive maternal responses, but the highest dose induced a stereotyped active response without interfering in the reflexive reaction. For offspring development, no differences in physical growth parameters were observed between the groups. However, considering reflex development, our results showed that negative geotaxis reflex development was delayed in the offspring at the lowest fipronil dose, and palmar grasp was lost earlier at the lowest and intermediate fipronil doses. These results suggest that the alterations observed herein may be due to either the GABAergic system or endocrine disruption, considering that fipronil

Emotion, reflexivity and social change in the era of extreme fossil fuels.

Science.gov (United States)

Davidson, Debra J

2018-05-09

Reflexivity is an important sociological lens through which to examine the means by which people engage in actions that contribute to social reproduction or social elaboration. Reflexivity theorists have largely overlooked the central place of emotions in reflexive processing, however, thus missing opportunities to enhance our understanding of reflexivity by capitalizing on recent scholarship on emotions emanating from other fields of inquiry. This paper explores the role of emotion in reflexivity, with a qualitative analysis of social responses to hydraulic fracturing in Alberta, Canada, utilizing narrative analysis of long-form interviews with rural landowners who have experienced direct impacts from hydraulic fracturing, and have attempted to voice their concerns in the public sphere. Based on interviews with a selection of two interview participants, the paper highlights the means by which emotions shape reflexivity in consequential ways, beginning with personal and highly individualized emotional responses to contingent situations, which then factor into the social interactions engaged in the pursuit of personal projects. The shared emotional context that emerges then plays a substantial role in shaping outcomes and their implications for social stasis or change. This study exemplifies the extent to which reflexive processing in response to breaches in the social order can be emotionally tumultuous affairs, constituting a significant personal toll that many may be unwilling to pay. © London School of Economics and Political Science 2018.

Central estrogenic pathways protect against the depressant action of acute nicotine on reflex tachycardia in female rats

International Nuclear Information System (INIS)

El-Mas, Mahmoud M.; Fouda, Mohamed A.; El-gowilly, Sahar M.; Saad, Evan I.

2012-01-01

We have previously shown that acute exposure of male rats to nicotine preferentially attenuates baroreceptor-mediated control of reflex tachycardia in contrast to no effect on reflex bradycardia. Here, we investigated whether female rats are as sensitive as their male counterparts to the baroreflex depressant effect of nicotine and whether this interaction is modulated by estrogen. Baroreflex curves relating reflex chronotropic responses evoked by i.v. doses (1–16 μg/kg) of phenylephrine (PE) or sodium nitroprusside (SNP), were constructed in conscious freely moving proestrus, ovariectomized (OVX), and estrogen (50 μg/kg/day s.c., 5 days)-replaced OVX (OVXE 2 ) rats. Slopes of the curves were taken as a measure of baroreflex sensitivity (BRS PE and BRS SNP ). Nicotine (100 μg/kg i.v.) reduced BRS SNP in OVX rats but not in proestrus or OVXE 2 rats. The attenuation of reflex tachycardia by nicotine was also evident in diestrus rats, which exhibited plasma estrogen levels similar to those of OVX rats. BRS PE was not affected by nicotine in all rat preparations. Experiments were then extended to determine whether central estrogenic receptors modulate the nicotine–BRS SNP interaction. Intracisteral (i.c.) treatment of OVX rats with estrogen sulfate (0.2 μg/rat) abolished the BRS SNP attenuating effect of i.v. nicotine. This protective effect of estrogen disappeared when OVX rats were pretreated with i.c. ICI 182,780 (50 μg/rat, selective estrogen receptor antagonist). Together, these findings suggest that central neural pools of estrogen receptors underlie the protection offered by E 2 against nicotine-induced baroreceptor dysfunction in female rats. -- Highlights: ► Estrogen protects against the depressant effect of nicotine on reflex tachycardia. ► The baroreflex response and estrogen status affect the nicotine–BRS interaction. ► The protection offered by estrogen is mediated via central estrogen receptors.

Laser induced nuclear orientation effects

International Nuclear Information System (INIS)

Burns, M.; Pappas, P.; Feld, M.S.; Murnick, D.E.

1977-01-01

Resonant laser radiation can orient metastable nuclei, resulting in spatially anisotropic emission of β or γ radiation. This technique can be used to obtain isomer shifts and nuclear moments and can lead to isomer separation. (Auth.)

Affective Modulation of the Startle Eyeblink and Postauricular Reflexes in Autism Spectrum Disorder

Science.gov (United States)

Dichter, Gabriel S.; Benning, Stephen D.; Holtzclaw, Tia N.; Bodfish, James W.

2010-01-01

Eyeblink and postauricular reflexes to standardized affective images were examined in individuals without (n = 37) and with (n = 20) autism spectrum disorders (ASDs). Affective reflex modulation in control participants replicated previous findings. The ASD group, however, showed anomalous reflex modulation patterns, despite similar self-report…

Changes in H-Reflex Recruitment After Trans-Spinal Direct Current Stimulation With Multiple Electrode Configurations

Directory of Open Access Journals (Sweden)

Alexander Kuck

2018-03-01

Full Text Available Trans-spinal direct current stimulation (tsDCS is an electro-modulatory tool with possible application in the rehabilitation of spinal cord injury. TsDCS generates a small electric field, aiming to induce lasting, functional neuromodulation in the targeted neuronal networks. Earlier studies have shown significant modulatory effects after application of lumbar tsDCS. However, for clinical application, a better understanding of application specific factors is required. Our goal was to investigate the effect of different electrode configurations using lumbar spinal tsDCS on spinal excitability. We applied tsDCS (2.5 mA, 15 min in 10 healthy subjects with three different electrode configurations: (1 Anode and cathode placed over vertebra T11, and the posterior left shoulder respectively (LSC-S (one polarity, and (2 Both electrodes placed in equal distance (ED (7 cm above and below vertebra T11, investigated for two polarities (ED-Anodal/Cathodal. The soleus H-Reflex is measured before, during and after tsDCS in either electrode configuration or a sham condition. To account for genetic predispositions in response to direct current stimulation, subject BDNF genotype was assessed. Stimulation in configuration ED-Cathodal induced an amplitude reduction of the H-reflex, 30 min after tsDCS with respect to baseline, whereas none of the other configurations led to significant post intervention effects. BDNF genotype did not correlate with post intervention effects. Furthermore, we failed to replicate effects shown by a previous study, which highlights the need for a better understanding of methodological and subject specific influences on tsDCS outcome. The H-reflex depression after tsDCS (Config. ED-Cathodal provides new insights and may foster our understanding of the working mechanism of tsDCS.

THE CONCEPT OF REFLEXIVE MANAGEMENT OF CONSUMER DEMAND

Directory of Open Access Journals (Sweden)

Maryna Mavrina

2017-11-01

Full Text Available Development of theoretical approaches of demand management is conducted from the moment of awareness of the importance of this concept. Many models of individual consumers were developed. However, to predict the reaction of consumers to the commercial policy of the enterprise, exact methods do not exist yet because the available ones are mostly empirical in nature. Models of behaviour often do not provide the expected result because they use an erroneous approach to the analysis of the mechanism of demand formation. The subject of the research is the theoretical and methodological basis, methods of assessment, and reflexive management of consumer demand of commercial enterprises. The purpose of the paper is developing a concept of reflexive management of consumer demand. To achieve the research goal, the following tasks are set and solved: to substantiate the theoretical and methodological foundations of reflexive consumer management, to analyse existing approaches to the modelling of consumer behaviour; to improve the model of consumer behaviour; to develop a concept of reflexive management of consumer behaviour. Methodology. In the paper, we use such methods and approaches to research as: reflexive approach (phenomenological method, behavioural economic theory, marketing approach, abstract-logical analysis, analysis of theoretical approaches to the modelling of consumer behaviour. Results. Modern approaches to modelling of consumer behaviour are mostly empirical in nature and have shortcomings of general models. In them, there is no description of specific situations of the purchase of goods. They cannot be quantified. Therefore, they cannot be practical models. But they have a weighty advantage in a comprehensive look at motivated purchases, what makes it possible to evaluate the relevance of individual variables and to understand the fundamental processes of consumer behaviour. It makes possible to identify the variables necessary for the

Suppression of the cough reflex by inhibition of ERK1/2 activation in the caudal nucleus tractus solitarii of the rabbit.

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Mutolo, Donatella; Bongianni, Fulvia; Cinelli, Elenia; Giovannini, Maria Grazia; Pantaleo, Tito

2012-04-15

The caudal nucleus tractus solitarii (cNTS), the predominant site of termination of cough-related afferents, has been shown to be a site of action of some centrally acting antitussive agents. A role of ERK1/2 has been suggested in acute central processing of nociceptive inputs. Because pain and cough share similar features, we investigated whether ERK1/2 activation could also be involved in the central transduction of tussive inputs. For this purpose, we undertook the present research on pentobarbital sodium-anesthetized, spontaneously breathing rabbits by using microinjections (30-50 nl) of an inhibitor of ERK1/2 activation (U0126) into the cNTS. Bilateral microinjections of 25 mM U0126 caused rapid and reversible reductions in the cough responses induced by both mechanical and chemical (citric acid) stimulation of the tracheobronchial tree. In particular, the cough number and peak abdominal activity decreased. Bilateral microinjections of 50 mM U0126 completely suppressed the cough reflex without affecting the Breuer-Hering inflation reflex, the pulmonary chemoreflex, and the sneeze reflex. These U0126-induced effects were, to a large extent, reversible. Bilateral microinjections of 50 mM U0124, the inactive analog of U0126, at the same cNTS sites had no effect. This is the first study that provides evidence that ERK1/2 activation within the cNTS is required for the mediation of cough reflex responses in the anesthetized rabbit. These results suggest a role for ERK1/2 in the observed effects via nontranscriptional mechanisms, given the short time involved. They also may provide hints for the development of novel antitussive strategies.

The ubiquitous reflex and its critics in post-revolutionary Russia.

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Sirotkina, Irina

2009-03-01

In the last century, the reflex was more than a scientific concept: it was a cultural idiom that could be used to various aims--political, scholarly, and artistic. In Russia in the 1920s, the reflex became a ubiquitous notion and a current word, part of the revolutionary discourse and, finally, a password to modernity. Two major factors contributed to it: physiological theories of the reflex, widespread in Russia at the early twentieth-century, and the materialist philosophy backed after the Revolution by the Communist party. Everybody who wished to be modern and materialist, in conformity with the official communist views, had to refer to reflexes. Yet, even in this period, the concept was not unproblematic and was criticized by some scientists, philosophers, artists and even Party members. In the paper, I describe both the array of uses of the term and the criticism it received in political, scientific and artistic discourses. It is not uncommon that, taking their origins in culture and common language, scientific concepts later return there in the form of metaphors. Similarly, the reflex was made into a rigorous scientific concept in the nineteenth century but, in the next century, it circulated as a cultural idiom penetrating various areas of political, artistic and academic life.

Effects of cold-pressor and mental arithmetic on pupillary light reflex

International Nuclear Information System (INIS)

Davis, B C; Daluwatte, C; Colona, N C; Yao, D G

2013-01-01

Dynamic pupillary light reflex (PLR) is a simple neurological test that can be useful for assessment of autonomic disorders. In this study, we investigated the changes in PLR induced by mental arithmetic task and cold pressor trials which are often applied in research as model systems to elicit autonomic responses. PLR was recorded before, during and after mental arithmetic and cold pressor tasks in 20 healthy adults (ten males and ten females). Stress-induced sympathetic activation was evident as shown in the increased blood pressure during both tasks. Although the pupillary constriction amplitude did not show significant changes, both constriction time and redilation time changed during the tasks. A significant gender effect was observed in cold pressor that suggested more sympathetic activation in males and faster parasympathetic activation in females in response to light stimulation under cold pressor. (paper)

Evaluation of cranial tibial and extensor carpi radialis reflexes before and after anesthetic block in cats.

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Tudury, Eduardo Alberto; de Figueiredo, Marcella Luiz; Fernandes, Thaiza Helena Tavares; Araújo, Bruno Martins; Bonelli, Marília de Albuquerque; Diogo, Camila Cardoso; Silva, Amanda Camilo; Santos, Cássia Regina Oliveira; Rocha, Nadyne Lorrayne Farias Cardoso

2017-02-01

Objectives This study aimed to test the extensor carpi radialis and cranial tibial reflexes in cats before and after anesthetic block of the brachial and lumbosacral plexus, respectively, to determine whether they depend on a myotatic reflex arc. Methods Fifty-five cats with a normal neurologic examination that were referred for elective gonadectomy were divided into group 1 (29 cats) for testing the extensor carpi radialis reflex, and group 2 (26 cats) for testing the cranial tibial reflex. In group 1, the extensor carpi radialis reflex was tested after anesthetic induction and 15 mins after brachial plexus block with lidocaine. In group 2, the cranial tibial, withdrawal and patellar reflexes were elicited in 52 hindlimbs and retested 15 mins after epidural anesthesia. Results In group 1, before the anesthetic block, 55.17% of the cats had a decreased and 44.83% had a normal extensor carpi radialis reflex. After the block, 68.96% showed a decreased and 27.59% a normal reflex. No cat had an increased or absent reflex before anesthetic block. In group 2, prior to the anesthetic block, 15.38% of the cats had a decreased cranial tibial reflex and 84.62% had a normal response, whereas after the block it was decreased in 26.92% and normal in 73.08% of the cats. None of the cats had an increased or absent reflex. Regarding the presence of both reflexes before and after anesthetic block, there was no significant difference at 1% ( P = 0.013). Conclusions and relevance The extensor carpi radialis and cranial tibial reflexes in cats are not strictly myotatic reflexes, as they are independent of the reflex arc, and may be idiomuscular responses. Therefore, they are not reliable for neurologic examination in this species.

Otolith and canal reflexes in human standing

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Cathers, Ian; Day, Brian L; Fitzpatrick, Richard C

2005-01-01

We used galvanic vestibular stimulation (GVS) to identify human balance reflexes of the semicircular canals and otolith organs. The experiment used a model of vestibular signals arising from GVS modulation of the net signal from vestibular afferents. With the head upright, the model predicts that the GVS-evoked canal signal indicates lateral head rotation while the otolith signal indicates lateral tilt or acceleration. Both signify body sway transverse to the head. With the head bent forward, the model predicts that the canal signal indicates body spin about a vertical axis but the otolith signal still signifies lateral body motion. Thus, we compared electromyograms (EMG) in the leg muscles and body sway evoked by GVS when subjects stood with the head upright or bent forward. With the head upright, GVS evoked a large sway in the direction of the anodal electrode. This response was abolished with the head bent forward leaving only small, oppositely directed, transient responses at the start and end of the stimulus. With the head upright, GVS evoked short-latency (60–70 ms), followed by medium-latency (120 ms) EMG responses, of opposite polarity. Bending the head forward abolished the medium-latency but preserved the short-latency response. This is compatible with GVS evoking separate otolithic and canal reflexes, indicating that balance is controlled by independent canal and otolith reflexes, probably through different pathways. We propose that the short-latency reflex and small transient sway are driven by the otolith organs and the medium-latency response and the large sway are driven by the semicircular canals. PMID:15618274

Interindividual differences in H reflex modulation during normal walking

DEFF Research Database (Denmark)

Simonsen, Erik B; Dyhre-Poulsen, Poul; Alkjaer, T

2002-01-01

was greater for the S group. The hip joint moment was similar for the groups. The EMG activity in the vastus lateralis and anterior tibial muscles was greater prior to heel strike for the S group. These data indicate that human walking exhibits at least two different motor patterns as evaluated by gating...... of afferent input to the spinal cord, by EMG activity and by walking mechanics. Increasing H reflex excitability during the swing phase appears to protect the subject against unexpected perturbations around heel strike by a facilitated stretch reflex in the triceps surae muscle. Alternatively, in subjects...... with a suppressed H reflex in the swing phase the knee joint extensors seem to form the primary protection around heel strike....

Shoulder reflexes

DEFF Research Database (Denmark)

Diederichsen, L.; Krogsgaard, M.; Voigt, Michael

2002-01-01

long latency (300 ms) excitatory reflex has been found when nerves in the capsule were stimulated electrically during shoulder surgery. In addition, when the anterior-inferior capsule was excited in conscious humans with modest amplitude electrical stimuli during muscle activity, a strong inhibition...... activity around the shoulder. This has implications for rehabilitation and shoulder surgery.......Dynamic shoulder stability is dependent on muscular coordination and sensory inputs. In the shoulder, mechanoreceptors are found in the coracoacromial ligament, the rotator cuff tendons, the musculotendinous junctions of the rotator cuff and in the capsule. The number of receptors in the capsule...

An Intelligent Computerized Stretch Reflex Measurement System For Clinical And Investigative Neurology

Science.gov (United States)

Flanagan, P. M.; Chutkow, J. G.; Riggs, M. T.; Cristiano, V. D.

1987-05-01

We describe the design of a reliable, user-friendly preprototype system for quantifying the tendon stretch reflexes in humans and large mammals. A hand-held, instrumented reflex gun, the impactor of which contains a single force sensor, interfaces with a computer. The resulting test system can deliver sequences of reproducible stimuli at graded intensities and adjustable durations to a muscle's tendon ("tendon taps"), measure the impacting force of each tap, and record the subsequent reflex muscle contraction from the same tendon -- all automatically. The parameters of the reflex muscle contraction include latency; mechanical threshold; and peak time, peak magnitude, and settling time. The results of clinical tests presented in this paper illustrate the system's potential usefulness in detecting neurologic dysfunction affecting the tendon stretch reflexes, in documenting the course of neurologic illnesses and their response to therapy, and in clinical and laboratory neurologic research.

Orthodoxy and reflexivity in international comparative analysis

DEFF Research Database (Denmark)

Lind, Jens; Valkenburg, Ben

2002-01-01

This contribution aims at four points.First we want to argue why we think a reflexive social science is more adequate than the orthodox consensus. In current practice much of the criticism on the orthodox consensus is shared on a theoretical level, without considering the implications and acting...... upon the consequences on the level of empirical research. We want to avoid that, so our second and third subject will be the practical implications of reflexivity for empirical research as well as for social policy. Our discussion on these subjects is based on the practical experiences in the INPART...

Behavior of the potential-induced degradation of photovoltaic modules fabricated using flat mono-crystalline silicon cells with different surface orientations

Science.gov (United States)

Yamaguchi, Seira; Masuda, Atsushi; Ohdaira, Keisuke

2016-04-01

This paper deals with the dependence of the potential-induced degradation (PID) of flat, p-type mono-crystalline silicon solar cell modules on the surface orientation of solar cells. The investigated modules were fabricated from p-type mono-crystalline silicon cells with a (100) or (111) surface orientation using a module laminator. PID tests were performed by applying a voltage of -1000 V to shorted module interconnector ribbons with respect to an Al plate placed on the cover glass of the modules at 85 °C. A decrease in the parallel resistance of the (100)-oriented cell modules is more significant than that of the (111)-oriented cell modules. Hence, the performance of the (100)-oriented-cell modules drastically deteriorates, compared with that of the (111)-oriented-cell modules. This implies that (111)-oriented cells offer a higher PID resistance.

The reflexive case study method

DEFF Research Database (Denmark)

Rittenhofer, Iris

2015-01-01

This paper extends the international business research on small to medium-sized enterprises (SME) at the nexus of globalization. Based on a conceptual synthesis across disciplines and theoretical perspectives, it offers management research a reflexive method for case study research of postnational...

Reconceptualizing reflexivity and dissonance in professional and personal domains.

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Brooks, Ann

2008-09-01

Debates around 'reflexivity' and the construction of the gendered self within late modernity have occupied the attention of both 'reflexive modernization' theorists (Beck, Giddens and Lash 1994; Beck and Beck-Gernsheim 1996; Giddens 1991, 1992) as well as gender and feminist theorists. While theorists such as Beck and Giddens have been preoccupied with establishing the connection between reflexivity and the construction of the 'non-gendered' self, gender and feminist theorists have sought to amplify the debate by exploring the intersecting nexus of contemporary theorizing, more fully within this context. This paper explores the theoretical underpinnings of these debates and their application to specific professional and personal domains. I consider three case studies to assess these issues as outlined in my own work, Brooks 2006, and in the work of Wajcman and Martin 2002, and McDowell 1997, which draw on empirical research and explore changes to gender identity within professional and personal domains. I conclude that there is little evidence in the research presented here of any systematic reconfiguring of gender identities leading to a detraditionalization of gender as suggested by the 'reflexive modernization' theorists.

Modulation of the masseteric reflex by gastric vagal afferents.

Science.gov (United States)

Pettorossi, V E

1983-04-01

Several investigations have shown that the vagal nerve can affect the reflex responses of the masticatory muscles acting at level either of trigeminal motoneurons or of the mesencephalic trigeminal nucleus (MTN). The present experiments have been devoted to establish the origin of the vagal afferent fibres involved in modulating the masseteric reflex. In particular, the gastric vagal afferents were taken into consideration and selective stimulations of such fibres were performed in rabbit. Conditioning electrical stimulation of truncus vagalis ventralis (TVV) reduced the excitability of the MTN cells as shown by a decrease of the antidromic response recorded from the semilunar ganglion and elicited by MTN single-shock electrical stimulation. Sympathetic and cardiovascular influences were not involved in these responses. Mechanical stimulation of gastric receptors, by means of gastric distension, clearly diminished the amplitude of twitch tension of masseteric reflex and inhibited the discharge frequency of proprioceptive MTN units. The effect was phasic and depended upon the velocity of distension. Thus the sensory volleys originating from rapid adapting receptors reach the brain stem through vagal afferents and by means of a polysynaptic connection inhibits the masseteric reflex at level of MTN cells.

Laughter-induced syncope.

Science.gov (United States)

Kim, Alexander J; Frishman, William H

2012-01-01

Reported cases of syncope caused directly by laughter are rare. The common scenario described in a few reports involved episodes of fortuitous laughter, sometimes followed by a short prodrome of lightheadedness, facial flushing, and dizziness, followed by an episode of definite syncope. There were no seizure-like movements, automatisms, or bladder or bowel incontinence. After the syncopal episodes that were seconds in length, the patients regained consciousness, and at that point were fully oriented. These episodes could recur in a similar situation with such laughter. Many of these patients subsequently underwent full syncope workups, without elucidating a primary cardiac or neurologic cause. In this review of laughter-induced syncope, we describe a patient of ours who fit these descriptions. This phenomenon is likely a subtype of benign Valsalva-related syncope, with autonomic reflex arcs coming into play that ultimately result in global cerebral hypoperfusion. Besides the Valsalva produced by a great fit of laughter, laughter itself has its own neuroendocrine and vasculature effects that may play a role.

Reflex reading epilepsy: effect of linguistic characteristics on spike frequency.

Science.gov (United States)

Safi, Dima; Lassonde, Maryse; Nguyen, Dang Khoa; Denault, Carole; Macoir, Joël; Rouleau, Isabelle; Béland, Renée

2011-04-01

Reading epilepsy is a rare reflex epilepsy in which seizures are provoked by reading. Several cases have been described in the literature, but the pathophysiological processes vary widely and remain unclear. We describe a 42-year-old male patient with reading epilepsy evaluated using clinical assessments and continuous video/EEG recordings. We administered verbal, nonverbal, and reading tasks to determine factors precipitating seizures. Linguistic characteristics of the words were manipulated. Results indicated that reading-induced seizures were significantly more numerous than those observed during verbal and nonverbal tasks. In reading tasks, spike frequency significantly increased with involvement of the phonological reading route. Spikes were recorded predominantly in left parasagittal regions. Future cerebral imaging studies will enable us to visualize the spatial localization and temporal course of reading-induced seizures and brain activity involved in reading. A better understanding of reading epilepsy is crucial for reading rehabilitation in these patients. Copyright © 2011 Elsevier Inc. All rights reserved.

Surgical desensitisation of the mechanoreceptors in Müller's muscle relieves chronic tension-type headache caused by tonic reflexive contraction of the occipitofrontalis muscle in patients with aponeurotic blepharoptosis.

Science.gov (United States)

Matsuo, Kiyoshi; Ban, Ryokuya

2013-02-01

Proprioceptively innervated intramuscular connective tissues in Müller's muscle function as exterior mechanoreceptors to induce reflex contraction of the levator and occipitofrontalis muscles. In aponeurotic blepharoptosis, since the levator aponeurosis is disinserted from the tarsus, stretching of the mechanoreceptors in Müller's muscle is increased even on primary gaze to induce phasic and tonic reflexive contraction of the occipitofrontalis muscle. It was hypothesised that in certain patients with aponeurotic blepharoptosis, the presence of tonic reflexive contraction of the occipitofrontalis muscle due to the sensitised mechanoreceptors in Müller's muscle, can cause chronic tension-type headache (CTTH) associated with occipitofrontalis tenderness. To verify this hypothesis, this study evaluated (1) what differentiates patients with CTTH from patients without CTTH, (2) how pharmacological contraction of Müller's smooth muscle fibres as a method for desensitising the mechanoreceptors in Müller's muscle affects electromyographic activity of the frontalis muscle, and (3) how surgical aponeurotic reinsertion to desensitise the mechanoreceptors in Müller's muscle electromyographically or subjectively affects activities of the occipitofrontalis muscle or CTTH. It was found that patients had sustained CTTH when light eyelid closure did not markedly reduce eyebrow elevation. However, pharmacological contraction of Müller's smooth muscle fibres or surgery to desensitise the mechanoreceptor electromyographically reduced the tonic contraction of the occipitofrontalis muscle on primary gaze and subjectively relieved aponeurotic blepharoptosis-associated CTTH. Over-stretching of the mechanoreceptors in Müller's muscle on primary gaze may induce CTTH due to tonic reflexive contraction of the occipitofrontalis muscle. Therefore, surgical desensitisation of the mechanoreceptors in Müller's muscle appears to relieve CTTH.

Soleus muscle H-reflex monitoring in endoscopic surgery under general anesthesia percutaneous interlaminar approach.

Science.gov (United States)

Wang, Huixue; Gao, Yingji; Ji, Lixin; Bai, Wanshan

2018-05-01

The clinical value of soleus muscle H-reflex monitoring in general anesthesia percutaneous interlaminar approach was investigated. A total of 80 cases with unilateral L5-S1 disc herniation between January 2015 and October 2016 were randomly divided into control group (without soleus muscle H-reflex monitoring, n=40) and observation group (with soleus muscle H-reflex monitoring, n=40). Results showed that the operation time of the observation group was shorter than that of the control group (Ph after operation, the amplitude of H-reflex in diseased side soleus muscle was significantly lower than that in healthy side (Ph postoperatively, the latency of H-reflex in diseased side soleus muscle was shorter than that of healthy side (PH-reflex latency in soleus muscle were significantly lower (PH-reflex monitoring can effectively reduce the damage to the nerve roots under percutaneous endoscopic intervertebral endoscopic surgery under general anesthesia, improve the accuracy of surgery, reduce the complications, shorten the operation time and reduce the surgical bleeding, which is more beneficial to patients smooth recovery.

Inhibition of reflex vagal bradycardia by a central action of 5-hydroxytryptophan.

OpenAIRE

Tadepalli, A. S.

1980-01-01

1 Vagally mediated reflex bradycardia was elicited in spinal cats with intravenous pressor doses of noradrenaline. Administration of 5-hydroxytryptophan (1.5 and 3 mg total dose) into the fourth cerebral ventricle reduced the reflex bradycardia. 2 Inhibition of central amino acid decarboxylase with R044602 prevented the effects of 5-hydroxytryptophan. After intravenous administration of 5-hydroxytryptophan, vagal reflex bradycardia was not affected. 3 Results suggest that 5-hydroxytryptophan ...

Fundamental Principles underlying Motor Reflexes

NARCIS (Netherlands)

K. Zhou (Kuikui)

2017-01-01

markdownabstractThe cerebellum has been suggested to be involved in motor control ever since the early 19th century. The motor control ranges from timing and strength of simple reflexes to multiple joint/limb coordination and complex motor sequence acquisition. The current thesis discusses the

Acid-sensing ion channels contribute to the metaboreceptor component of the exercise pressor reflex

OpenAIRE

McCord, Jennifer L.; Tsuchimochi, Hirotsugu; Kaufman, Marc P.

2009-01-01

The exercise pressor reflex is evoked by both mechanical and metabolic stimuli arising in contracting skeletal muscle. Recently, the blockade of acid-sensing ion channels (ASICs) with amiloride and A-316567 attenuated the reflex. Moreover, amiloride had no effect on the mechanoreceptor component of the reflex, prompting us to determine whether ASICs contributed to the metaboreceptor component of the exercise pressor reflex. The metaboreceptor component can be assessed by measuring mean arteri...

Effects of brainstem lesions on the masseter inhibitory reflex. Functional mechanisms of reflex pathways

NARCIS (Netherlands)

Ongerboer de Visser, B. W.; Cruccu, G.; Manfredi, M.; Koelman, J. H.

1990-01-01

The masseter inhibitory reflex (MIR) was investigated in 16 patients with localized brainstem lesions involving the trigeminal system. The MIR consists of two phases of EMG silence (S1 and S2) evoked by stimulation of the mental nerve during maximal clenching of the teeth. The extent of the lesions

Hip proprioceptors preferentially modulate reflexes of the leg in human spinal cord injury

Science.gov (United States)

Onushko, Tanya; Hyngstrom, Allison

2013-01-01

Stretch-sensitive afferent feedback from hip muscles has been shown to trigger long-lasting, multijoint reflex responses in people with chronic spinal cord injury (SCI). These reflexes could have important implications for control of leg movements during functional activities, such as walking. Because the control of leg movement relies on reflex regulation at all joints of the limb, we sought to determine whether stretch of hip muscles modulates reflex activity at the knee and ankle and, conversely, whether knee and ankle stretch afferents affect hip-triggered reflexes. A custom-built servomotor apparatus was used to stretch the hip muscles in nine chronic SCI subjects by oscillating the legs about the hip joint bilaterally from 10° of extension to 40° flexion. To test whether stretch-related feedback from the knee or ankle would be affected by hip movement, patellar tendon percussions and Achilles tendon vibration were delivered when the hip was either extending or flexing. Surface electromyograms (EMGs) and joint torques were recorded from both legs. Patellar tendon percussions and Achilles tendon vibration both elicited reflex responses local to the knee or ankle, respectively, and did not influence reflex responses observed at the hip. Rather, the movement direction of the hip modulated the reflex responses local to the joint. The patellar tendon reflex amplitude was larger when the perturbation was delivered during hip extension compared with hip flexion. The response to Achilles vibration was modulated by hip movement, with an increased tonic component during hip flexion compared with extension. These results demonstrate that hip-mediated sensory signals modulate activity in distal muscles of the leg and appear to play a unique role in modulation of spastic muscle activity throughout the leg in SCI. PMID:23615544

Spasm of the near reflex: a spectrum of anomalies.

Science.gov (United States)

Goldstein, J H; Schneekloth, B B

1996-01-01

Spasm of the near reflex has been characterized as the variable appearance of pseudomyopia, convergent strabismus and miosis. These characteristics may appear together or separately. In addition, abnormalities of accommodation may appear not only as pseudomyopia, but may also be manifest in cases with significant hypermetropia in which the patient is unable to relax accommodation even when plus lenses are used. The intent of this review is to identify the various clinical presentations of anomalies of the entire near reflex as well as the component parts. The relationship to functional and organic disorders are discussed as well as the related neuroanatomy. We suggest that one may more readily understand the clinical manifestations as a spectrum of anomalies of the near reflex rather than a multitude of disconnected entities.

Rigorous theory of molecular orientational nonlinear optics

International Nuclear Information System (INIS)

Kwak, Chong Hoon; Kim, Gun Yeup

2015-01-01

Classical statistical mechanics of the molecular optics theory proposed by Buckingham [A. D. Buckingham and J. A. Pople, Proc. Phys. Soc. A 68, 905 (1955)] has been extended to describe the field induced molecular orientational polarization effects on nonlinear optics. In this paper, we present the generalized molecular orientational nonlinear optical processes (MONLO) through the calculation of the classical orientational averaging using the Boltzmann type time-averaged orientational interaction energy in the randomly oriented molecular system under the influence of applied electric fields. The focal points of the calculation are (1) the derivation of rigorous tensorial components of the effective molecular hyperpolarizabilities, (2) the molecular orientational polarizations and the electronic polarizations including the well-known third-order dc polarization, dc electric field induced Kerr effect (dc Kerr effect), optical Kerr effect (OKE), dc electric field induced second harmonic generation (EFISH), degenerate four wave mixing (DFWM) and third harmonic generation (THG). We also present some of the new predictive MONLO processes. For second-order MONLO, second-order optical rectification (SOR), Pockels effect and difference frequency generation (DFG) are described in terms of the anisotropic coefficients of first hyperpolarizability. And, for third-order MONLO, third-order optical rectification (TOR), dc electric field induced difference frequency generation (EFIDFG) and pump-probe transmission are presented

Concerted orientation induced unidirectional water transport through nanochannels.

Science.gov (United States)

Wan, Rongzheng; Lu, Hangjun; Li, Jinyuan; Bao, Jingdong; Hu, Jun; Fang, Haiping

2009-11-14

The dynamics of water inside nanochannels is of great importance for biological activities as well as for the design of molecular sensors, devices, and machines, particularly for sea water desalination. When confined in specially sized nanochannels, water molecules form a single-file structure with concerted dipole orientations, which collectively flip between the directions along and against the nanotube axis. In this paper, by using molecular dynamics simulations, we observed a net flux along the dipole-orientation without any application of an external electric field or external pressure difference during the time period of the particular concerted dipole orientations of the molecules along or against the nanotube axis. We found that this unique special-directional water transportation resulted from the asymmetric potential of water-water interaction along the nanochannel, which originated from the concerted dipole orientation of the water molecules that breaks the symmetry of water orientation distribution along the channel within a finite time period. This finding suggests a new mechanism for achieving high-flux water transportation, which may be useful for nanotechnology and biological applications.

[Developing team reflexivity as a learning and working tool for medical teams].

Science.gov (United States)

Riskin, Arieh; Bamberger, Peter

2014-01-01

Team reflexivity is a collective activity in which team members review their previous work, and develop ideas on how to modify their work behavior in order to achieve better future results. It is an important learning tool and a key factor in explaining the varying effectiveness of teams. Team reflexivity encompasses both self-awareness and agency, and includes three main activities: reflection, planning, and adaptation. The model of briefing-debriefing cycles promotes team reflexivity. Its key elements include: Pre-action briefing--setting objectives, roles, and strategies the mission, as well as proposing adaptations based on what was previously learnt from similar procedures; Post-action debriefing--reflecting on the procedure performed and reviewing the extent to which objectives were met, and what can be learnt for future tasks. Given the widespread attention to team-based work systems and organizational learning, efforts should be made toward ntroducing team reflexivity in health administration systems. Implementation could be difficult because most teams in hospitals are short-lived action teams formed for a particular event, with limited time and opportunity to consciously reflect upon their actions. But it is precisely in these contexts that reflexive processes have the most to offer instead of the natural impulsive collective logics. Team reflexivity suggests a potential solution to the major problems of iatorgenesis--avoidable medical errors, as it forces all team members to participate in a reflexive process together. Briefing-debriefing technology was studied mainly in surgical teams and was shown to enhance team-based learning and to improve quality-related outcomes and safety.

A tapetal-like fundus reflex in a healthy male

DEFF Research Database (Denmark)

Schatz, Patrik; Bregnhøj, Jesper; Arvidsson, Henrik

2012-01-01

To report on the retinal function and structure in a 37-year-old male who presented with a tapetal-like reflex (TLR) indistinguishable from that seen in female carriers of X-linked retinitis pigmentosa (XLRP).......To report on the retinal function and structure in a 37-year-old male who presented with a tapetal-like reflex (TLR) indistinguishable from that seen in female carriers of X-linked retinitis pigmentosa (XLRP)....

Automated data reduction workflows for astronomy. The ESO Reflex environment

Science.gov (United States)

Freudling, W.; Romaniello, M.; Bramich, D. M.; Ballester, P.; Forchi, V.; García-Dabló, C. E.; Moehler, S.; Neeser, M. J.

2013-11-01

Context. Data from complex modern astronomical instruments often consist of a large number of different science and calibration files, and their reduction requires a variety of software tools. The execution chain of the tools represents a complex workflow that needs to be tuned and supervised, often by individual researchers that are not necessarily experts for any specific instrument. Aims: The efficiency of data reduction can be improved by using automatic workflows to organise data and execute a sequence of data reduction steps. To realize such efficiency gains, we designed a system that allows intuitive representation, execution and modification of the data reduction workflow, and has facilities for inspection and interaction with the data. Methods: The European Southern Observatory (ESO) has developed Reflex, an environment to automate data reduction workflows. Reflex is implemented as a package of customized components for the Kepler workflow engine. Kepler provides the graphical user interface to create an executable flowchart-like representation of the data reduction process. Key features of Reflex are a rule-based data organiser, infrastructure to re-use results, thorough book-keeping, data progeny tracking, interactive user interfaces, and a novel concept to exploit information created during data organisation for the workflow execution. Results: Automated workflows can greatly increase the efficiency of astronomical data reduction. In Reflex, workflows can be run non-interactively as a first step. Subsequent optimization can then be carried out while transparently re-using all unchanged intermediate products. We found that such workflows enable the reduction of complex data by non-expert users and minimizes mistakes due to book-keeping errors. Conclusions: Reflex includes novel concepts to increase the efficiency of astronomical data processing. While Reflex is a specific implementation of astronomical scientific workflows within the Kepler workflow

Monosynaptic Stretch Reflex Fails to Explain the Initial Postural Response to Sudden Lateral Perturbations

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Andreas Mühlbeier

2017-06-01

Full Text Available Postural reflexes are essential for locomotion and postural stability, and may play an important role in the etiology of chronic back pain. It has recently been theoretically predicted, and with the help of unilateral perturbations of the trunk experimentally confirmed that the sensorimotor control must lower the reflex amplitude for increasing reflex delays to maintain spinal stability. The underlying neuromuscular mechanism for the compensation of postural perturbations, however, is not yet fully understood. In this study, we applied unilateral and bilateral sudden external perturbations to the trunk of healthy subjects and measured the muscular activity and the movement onset of the trunk. We found that the onset of the trunk muscle activity is prior to, or coincident with, the onset of the trunk movement. Additionally, the results of our experiments imply that the muscular response mechanism integrates distant sensory information from both sides of the body. These findings rule out a simple monosynaptic stretch reflex in favor of a more complex polysynaptic postural reflex mechanism to compensate postural perturbations. Moreover, the previously predicted negative correlation between reflex delay and reflex gain was also confirmed for bilateral perturbations.

Soleus stretch reflex during cycling

DEFF Research Database (Denmark)

Grey, Michael James; Pierce, C. W.; Milner, T. E.

2001-01-01

The modulation and strength of the human soleus short latency stretch reflex was investigated by mechanically perturbing the ankle during an unconstrained pedaling task. Eight subjects pedaled at 60 rpm against a preload of 10 Nm. A torque pulse was applied to the crank at various positions durin...

Low Incidence Of Extensor Plantar Reflex In Newborns In An ...

African Journals Online (AJOL)

Healthy term newborns with Apgar score of 8 and above at one minute were recruited into the study consecutively in a maternity hospital in Ibadan, Nigeria. The plantar reflex was elicited by stroking the lateral side of the sole with firm pressure, between 24 - 48 hours after delivery. Results Of 461 newborns, the plantar reflex ...

Functionality of the contralateral biceps femoris reflex response during human walking

DEFF Research Database (Denmark)

Stevenson, Andrew James Thomas; Geertsen, Svend Sparre; Sinkjaer, Thomas

2014-01-01

of the body in order to maintain dynamic equilibrium during walking. Therefore, we hypothesized that if we suddenly slowed the treadmill participants were walking on, the cBF reflex would be inhibited because the necessity to break the forward progression of the body would be decreased. Conversely, if we...... the treadmill velocity was altered concurrently or 50 ms after knee perturbation onset. These results, together with the finding that the cBF reflex response is under some cortical control [1], strongly suggest a functional role for the cBF reflex during walking that is adaptable to the environmental situation....

VizieR Online Data Catalog: RefleX : X-ray-tracing code (Paltani+, 2017)

Science.gov (United States)

Paltani, S.; Ricci, C.

2017-11-01

We provide here the RefleX executable, for both Linux and MacOSX, together with the User Manual and example script file and output file Running (for instance): reflex_linux will produce the file reflex.out Note that the results may differ slightly depending on the OS, because of slight differences in some implementations numerical computations. The difference are scientifically meaningless. (5 data files).

Motricidade reflexa na morte cerebral The reflex activity in the brain death

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Wilson L. Sanvito

1972-03-01

Full Text Available O diagnóstico de morte cerebral está baseado em critérios clínicos, eletrencefalográficos e angiográficos. Do ponto de vista clínico deve ser evidenciado o seguinte quadro: coma profundo, midríase paralítica bilateral, ausência de reação a qualquer estímulo externo, apnéia, arreflexia superficial e profunda. Do ponto de vista eletrencefalográfico são necessários dois registros, separados por um intervalo de 24 horas, evidenciando traçados iselétricos. No presente trabalho são estudados 15 pacientes com morte cerebral comprovada do ponto de vista clínico e eletrencefalográfico. Em 8 pacientes havia persistência de atividade reflexa durante a fase de morte cerebral (reflexos profundos e/ou superficiais. Fenômenos de automatismos medulares também foram verificados em 3 pacientes.The diagnosis of brain death is based in clinical, electroencephalographic and angiographic data. The criteria for diagnosis of brain death are: deep coma with unreceptivity and unresponsiveness, no movements or breathing (the patient's respiration must be maintained artificially, bilateral dilated and fixed pupils, absence of corneal reflexes, no response to caloric test, absence of deep tendon reflexes and of the superficial abdominal and plantar reflexes, isoelectric EEG maintained for twenty-four hours. The purpose of this study was to observe the natural clinical courses of 15 patients with brain death, specially the data concerning the deep and superficial reflexes. From 15 patients fulfilling the criteria of brain death, 8 maintained spinal reflexes up to the time of cardiac arrest; in five of these patients the superficial abdominal reflexes were present and the reflexes of spinal automatism could be elicited. These results show that the absence of deep and superficial reflexes can't be considered as essencial for the diagnosis of brain death.

A task dependent change in the medium latency component of the soleus stretch reflex

DEFF Research Database (Denmark)

Grey, Michael James; Larsen, Birgit; Sinkjær, Thomas

2002-01-01

In comparison to the H-reflex, the task dependency of the human stretch reflex during locomotive and postural tasks has not received a great deal of attention in the literature. The few studies on reflex task dependency that have been performed to date have concentrated on either the group Ia...

Erecting Closets and Outing Ourselves: Uncomfortable Reflexivity and Community-Based Research

Science.gov (United States)

Reed, Sarah J.; Miller, Robin Lin; Nnawulezi, Nkiru; Valenti, Maria T.

2012-01-01

Feminist scholars and community psychologists have argued that reflexivity is a necessary component to conducting socially conscious research. Reflexivity, however, is rarely evident in community psychology. In this article, we share the uncomfortable realities that surfaced during a community-based research project in which we adapted and…

A critical reflexive Perspective on othering in collaborative knowledge production

DEFF Research Database (Denmark)

Jakobsen, Helle Nordentoft; Olesen, Birgitte Ravn

2018-01-01

Purpose The purpose of the article is to show power mechanisms of in- and exclusion in moments where certain participants appeared to be othered in two collaborative research and development projects in a health care setting. Design/methodology/approach The article contributes to critical......-reflexive analyses of reflexive processes within collaborative knowledge production We use an analytical framework combining Bakhtin and Foucault to investigate processes of inclusion and exclusion in the interplay between dominant and subordinated voices in a moment-by-moment analysis of two incidents from...... interdisciplinary workshops. Findings The analysis illuminates how differences between voices challenge participants’ reflexive awareness and lead to the reproduction of contextual power and knowledge hierarchies and the concomitant silencing of particular participants. Thus, the findings draw attention...

The Reflexive Principle of Sociological Theorization

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R T Ubaidullayeva

2013-12-01

Full Text Available The article attempts to describe the reflexive principle in theory-making, which integrates the basic modern methodological paradigms and lays the foundation for the development of sociology. On the basis of the theoretical ideas of P. Bourdieu, A. Giddens and P. Ricoeur the author defines the concept of social reflexion and reveals its peculiarities in sociology as compared to reflexion in philosophy. According to the author, the fulfillment of reflexive functions in sociology is connected with the task of analyzing the complex structure of the polysemantic object, considering the specific quality of the subjects and their various trends of development. The presence of the poles — objectivity-subjectivity, rationality-irrationality, consciousness-unconsciousness etc, requires a reproduction of the dichotomies engendering them in social life and development of cognitive methods for their study in sociology.

Central estrogenic pathways protect against the depressant action of acute nicotine on reflex tachycardia in female rats

Energy Technology Data Exchange (ETDEWEB)

El-Mas, Mahmoud M., E-mail: mahelm@hotmail.com; Fouda, Mohamed A.; El-gowilly, Sahar M.; Saad, Evan I.

2012-02-01

We have previously shown that acute exposure of male rats to nicotine preferentially attenuates baroreceptor-mediated control of reflex tachycardia in contrast to no effect on reflex bradycardia. Here, we investigated whether female rats are as sensitive as their male counterparts to the baroreflex depressant effect of nicotine and whether this interaction is modulated by estrogen. Baroreflex curves relating reflex chronotropic responses evoked by i.v. doses (1–16 μg/kg) of phenylephrine (PE) or sodium nitroprusside (SNP), were constructed in conscious freely moving proestrus, ovariectomized (OVX), and estrogen (50 μg/kg/day s.c., 5 days)-replaced OVX (OVXE{sub 2}) rats. Slopes of the curves were taken as a measure of baroreflex sensitivity (BRS{sub PE} and BRS{sub SNP}). Nicotine (100 μg/kg i.v.) reduced BRS{sub SNP} in OVX rats but not in proestrus or OVXE{sub 2} rats. The attenuation of reflex tachycardia by nicotine was also evident in diestrus rats, which exhibited plasma estrogen levels similar to those of OVX rats. BRS{sub PE} was not affected by nicotine in all rat preparations. Experiments were then extended to determine whether central estrogenic receptors modulate the nicotine–BRS{sub SNP} interaction. Intracisteral (i.c.) treatment of OVX rats with estrogen sulfate (0.2 μg/rat) abolished the BRS{sub SNP} attenuating effect of i.v. nicotine. This protective effect of estrogen disappeared when OVX rats were pretreated with i.c. ICI 182,780 (50 μg/rat, selective estrogen receptor antagonist). Together, these findings suggest that central neural pools of estrogen receptors underlie the protection offered by E{sub 2} against nicotine-induced baroreceptor dysfunction in female rats. -- Highlights: ► Estrogen protects against the depressant effect of nicotine on reflex tachycardia. ► The baroreflex response and estrogen status affect the nicotine–BRS interaction. ► The protection offered by estrogen is mediated via central estrogen receptors.

Realization of highly crystallographic three-dimensional nanosheets by a stress-induced oriented-diffusion method

Energy Technology Data Exchange (ETDEWEB)

Gharooni, M.; Hosseini, M.; Mohajerzadeh, S., E-mail: mohajer@ut.ac.ir; Taghinejad, M.; Taghinejad, H. [Thin Film and Nanoelectronics Lab, Nanoelectronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran, Tehran 143957131 (Iran, Islamic Republic of); Abdi, Y. [Nano-Physics Research Lab, Department of Physics, University of Tehran, Tehran 1439955961 (Iran, Islamic Republic of)

2014-07-28

Morphologically controlled nanostructures have been increasingly important because of their strongly shape dependent physical and chemical properties. Formation of nanoscale silicon based structures that employ high levels of strain, intentional, and unintentional twins or grain boundaries can be dramatically different from the commonly conceived bulk processes. We report, realization of highly crystallographic 3D nanosheets with unique morphology and ultra-thin thickness by a stress-induced oriented-diffusion method, based on plasma processing of metal layer deposited on Si substrate and its post deep reactive ion etching. Annealing in plasma ambient creates rod-like metal alloy precursors which induce stress at its interface with Si substrate due to the mismatch of lattice constants. This stress opens facilitated gateways for orientated-diffusion of metal atoms in 〈110〉 directions and leads to formation of NSs (nanosheets) with [111] crystalline essence. Nanosheets are mainly triangular, hexagonal, or pseudo hexagonal in shape and their thicknesses are well controlled from several to tens of nanometers. The structural and morphological evolution of features were investigated in detail using transmission electron microscope, atomic force microscope, scanning electron microscope and possible mechanism is proposed to explain the formation of the thermodynamically unfavorable morphology of nanosheets. Significant photoemission capability of NSs was also demonstrated by photoluminescence spectroscopy.

Grounded theory research: literature reviewing and reflexivity.

Science.gov (United States)

McGhee, Gerry; Marland, Glenn R; Atkinson, Jacqueline

2007-11-01

This paper is a report of a discussion of the arguments surrounding the role of the initial literature review in grounded theory. Researchers new to grounded theory may find themselves confused about the literature review, something we ourselves experienced, pointing to the need for clarity about use of the literature in grounded theory to help guide others about to embark on similar research journeys. The arguments for and against the use of a substantial topic-related initial literature review in a grounded theory study are discussed, giving examples from our own studies. The use of theoretically sampled literature and the necessity for reflexivity are also discussed. Reflexivity is viewed as the explicit quest to limit researcher effects on the data by awareness of self, something seen as integral both to the process of data collection and the constant comparison method essential to grounded theory. A researcher who is close to the field may already be theoretically sensitized and familiar with the literature on the study topic. Use of literature or any other preknowledge should not prevent a grounded theory arising from the inductive-deductive interplay which is at the heart of this method. Reflexivity is needed to prevent prior knowledge distorting the researcher's perceptions of the data.

Collaborative Research in Contexts of Inequality: The Role of Social Reflexivity

Science.gov (United States)

Leibowitz, Brenda; Bozalek, Vivienne; Farmer, Jean; Garraway, James; Herman, Nicoline; Jawitz, Jeff; McMillan, Wendy; Mistri, Gita; Ndebele, Clever; Nkonki, Vuyisile; Quinn, Lynn; van Schalkwyk, Susan; Vorster, Jo-Anne; Winberg, Chris

2017-01-01

This article reports on the role and value of social reflexivity in collaborative research in contexts of extreme inequality. Social reflexivity mediates the enablements and constraints generated by the internal and external contextual conditions impinging on the research collaboration. It fosters the ability of participants in a collaborative…

Effect of joint mobilization on the H Reflex amplitude in people with spasticity

OpenAIRE

Pérez Parra, Julio Ernesto; Henao Lema, Claudia Patricia

2011-01-01

Objective: To determine the effect of ankle joint mobilization on the H reflex amplitude of thesoleus muscle in people with spasticity. Materials and methods: A quasi-experimental study withcrossover design and simple masking was conducted in 24 randomized subjects to initiate thecontrol or experimental group. Traction and rhythmic oscillation were applied for five minutesto the ankle joint. H wave amplitude changes of Hoffmann reflex (electrical equivalent of themonosynaptic spinal reflex) w...

Turtle Flexion Reflex Motor Patterns Show Windup, Mediated Partly by L-type Calcium Channels

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Keith P. Johnson

2017-10-01

Full Text Available Windup is a form of multisecond temporal summation in which identical stimuli, delivered seconds apart, trigger increasingly strong neuronal responses. L-type Ca2+ channels have been shown to play an important role in the production of windup of spinal cord neuronal responses, initially in studies of turtle spinal cord and later in studies of mammalian spinal cord. L-type Ca2+ channels have also been shown to contribute to windup of limb withdrawal reflex (flexion reflex in rats, but flexion reflex windup has not previously been described in turtles and its cellular mechanisms have not been studied. We studied windup of flexion reflex motor patterns, evoked with weak mechanical and electrical stimulation of the dorsal hindlimb foot skin and assessed via a hip flexor (HF nerve recording, in spinal cord-transected and immobilized turtles in vivo. We found that an L-type Ca2+ channel antagonist, nifedipine, applied at concentrations of 50 μM or 100 μM to the hindlimb enlargement spinal cord, significantly reduced windup of flexion reflex motor patterns, while lower concentrations of nifedipine had no such effect. Nifedipine similarly reduced the amplitude of an individual flexion reflex motor pattern evoked by a stronger mechanical stimulus, in a dose-dependent manner, suggesting that L-type Ca2+ channels contribute to each flexion reflex as well as to multisecond summation of flexion reflex responses in turtles. We also found that we could elicit flexion reflex windup consistently using a 4-g von Frey filament, which is not usually considered a nociceptive stimulus. Thus, it may be that windup can be evoked by a wide range of tactile stimuli and that L-type calcium channels contribute to multisecond temporal summation of diverse tactile stimuli across vertebrates.

A reflexing electron microwave amplifier for rf particle accelerator applications

International Nuclear Information System (INIS)

Fazio, M.V.; Hoeberling, R.F.

1988-01-01

The evolution of rf-accelerator technology toward high-power, high-current, low-emittance beams produces an ever-increasing demand for efficient, very high power microwave power sources. The present klystron technology has performed very well but is not expected to produce reliable gigawatt peak-power units in the 1- to 10-GHz regime. Further major advancements must involve other types of sources. The reflexing-electron class of sources can produce microwave powers at the gigawatt level and has demonstrated operation from 800-MHz to 40-GHz. The pulse length appears to be limited by diode closure, and reflexing-electron devices have been operated in a repetitively pulsed mode. A design is presented for a reflexing electron microwave amplifier that is frequency and phase locked. In this design, the generated microwave power can be efficiently coupled to one or several accelerator loads. Frequency and phase-locking capability may permit parallel-source operation for higher power. The low-frequency (500-MHz to 10-GHz) operation at very high power required by present and proposed microwave particle accelerators makes an amplifier, based on reflexing electron phenomena, a candidate for the development of new accelerator power sources. (author)

Fixed Pupillary Light Reflex due to Peripheral Neuropathy after Liver Transplantation

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Kwan Hyung Kim

2015-08-01

Full Text Available A 46-year-old female patient was admitted to the intensive care unit (ICU after liver transplantation. About an hour later after the ICU admission, she had no pupillary light reflex. Both pupils were also fixed at 5 mm. Patients who undergo liver transplantation are susceptible to neurologic disorders including hepatic encephalopathy, thromboembolism and intracranial hemorrhage. Abnormal pupillary light reflex usually indicates a serious neurologic emergency in these patients; however, benign neurologic disorders such as peripheral autonomic neuropathy or Holmes-Adie syndrome should also be considered. We experienced a case of fixed pupillary light reflex after liver transplantation diagnosed as peripheral autonomic neuropathy.

Intralimb and Interlimb Cutaneous Reflexes during Locomotion in the Intact Cat.

Science.gov (United States)

Hurteau, Marie-France; Thibaudier, Yann; Dambreville, Charline; Danner, Simon M; Rybak, Ilya A; Frigon, Alain

2018-04-25

When the foot contacts an obstacle during locomotion, cutaneous inputs activate spinal circuits to ensure dynamic balance and forward progression. In quadrupeds, this requires coordinated reflex responses between the four limbs. Here, we investigated the patterns and phasic modulation of cutaneous reflexes in forelimb and hindlimb muscles evoked by inputs from all four limbs. Five female cats were implanted to record muscle activity and to stimulate the superficial peroneal and superficial radial nerves during locomotion. Stimulating these nerves evoked short-, mid-, and longer-latency excitatory and/or inhibitory responses in all four limbs that were phase-dependent. The largest responses were generally observed during the peak activity of the muscle. Cutaneous reflexes during mid-swing were consistent with flexion of the homonymous limb and accompanied by modification of the stance phases of the other three limbs, by coactivating flexors and extensors and/or by delaying push-off. Cutaneous reflexes during mid-stance were consistent with stabilizing the homonymous limb by delaying and then facilitating its push-off and modifying the support phases of the homolateral and diagonal limbs, characterized by coactivating flexors and extensors, reinforcing extensor activity and/or delaying push-off. The shortest latencies of homolateral and diagonal responses were consistent with fast-conducting disynaptic or trisynaptic pathways. Descending homolateral and diagonal pathways from the forelimbs to the hindlimbs had a higher probability of eliciting responses compared with ascending pathways from the hindlimbs to the forelimbs. Thus, in quadrupeds, intralimb and interlimb reflexes activated by cutaneous inputs ensure dynamic coordination of the four limbs, producing a whole-body response. SIGNIFICANCE STATEMENT The skin contains receptors that, when activated, send inputs to spinal circuits, signaling a perturbation. Rapid responses, or reflexes, in muscles of the

Effect of straining on diaphragmatic crura with identification of the straining-crural reflex. The "reflex theory" in gastroesophageal competence

Directory of Open Access Journals (Sweden)

El Sibai Olfat

2004-09-01

Full Text Available Abstract Background The role of the crural diaphragm during increased intra-abdominal pressure is not exactly known. We investigated the hypothesis that the crural diaphragm undergoes reflex phasic contraction on elevation of the intra-abdominal pressure with a resulting increase of the lower esophageal pressure and prevention of gastro-esophageal reflux. Methods The esophageal pressure and crural diaphragm electromyographic responses to straining were recorded in 16 subjects (10 men, 6 women, age 36.6 ± 11.2 SD years during abdominal hernia repair. The electromyogram of crural diaphragm was recorded by needle electrode inserted into the crural diaphragm, and the lower esophageal pressure by a saline-perfused catheter. The study was repeated after crural anesthetization and after crural infiltration with saline. Results The crural diaphragm exhibited resting electromyographic activity which showed a significant increase on sudden (coughing, p Conclusions Straining effected an increase of the electromyographic activity of the crural diaphragm and of the lower esophageal pressure. This effect is suggested to be reflex in nature and to be mediated through the "straining-crural reflex". The crural diaphragm seems to play a role in the lower esophageal competence mechanism. Further studies are required to assess the clinical significance of the current results in gastro-esophageal reflux disease and hiatus hernia.

Restoring walking after spinal cord injury: operant conditioning of spinal reflexes can help.

Science.gov (United States)

Thompson, Aiko K; Wolpaw, Jonathan R

2015-04-01

People with incomplete spinal cord injury (SCI) frequently suffer motor disabilities due to spasticity and poor muscle control, even after conventional therapy. Abnormal spinal reflex activity often contributes to these problems. Operant conditioning of spinal reflexes, which can target plasticity to specific reflex pathways, can enhance recovery. In rats in which a right lateral column lesion had weakened right stance and produced an asymmetrical gait, up-conditioning of the right soleus H-reflex, which increased muscle spindle afferent excitation of soleus, strengthened right stance and eliminated the asymmetry. In people with hyperreflexia due to incomplete SCI, down-conditioning of the soleus H-reflex improved walking speed and symmetry. Furthermore, modulation of electromyographic activity during walking improved bilaterally, indicating that a protocol that targets plasticity to a specific pathway can trigger widespread plasticity that improves recovery far beyond that attributable to the change in the targeted pathway. These improvements were apparent to people in their daily lives. They reported walking faster and farther, and noted less spasticity and better balance. Operant conditioning protocols could be developed to modify other spinal reflexes or corticospinal connections; and could be combined with other therapies to enhance recovery in people with SCI or other neuromuscular disorders. © The Author(s) 2014.

Strong orientational coordinates and orientational order parameters for symmetric objects

International Nuclear Information System (INIS)

Haji-Akbari, Amir; Glotzer, Sharon C

2015-01-01

Recent advancements in the synthesis of anisotropic macromolecules and nanoparticles have spurred an immense interest in theoretical and computational studies of self-assembly. The cornerstone of such studies is the role of shape in self-assembly and in inducing complex order. The problem of identifying different types of order that can emerge in such systems can, however, be challenging. Here, we revisit the problem of quantifying orientational order in systems of building blocks with non-trivial rotational symmetries. We first propose a systematic way of constructing orientational coordinates for such symmetric building blocks. We call the arising tensorial coordinates strong orientational coordinates (SOCs) as they fully and exclusively specify the orientation of a symmetric object. We then use SOCs to describe and quantify local and global orientational order, and spatiotemporal orientational correlations in systems of symmetric building blocks. The SOCs and the orientational order parameters developed in this work are not only useful in performing and analyzing computer simulations of symmetric molecules or particles, but can also be utilized for the efficient storage of rotational information in long trajectories of evolving many-body systems. (paper)

Current-Induced Switching of a Single-Molecule Magnet with Arbitrary Oriented Easy Axis

OpenAIRE

Misiorny, Maciej; Barnas, Józef

2007-01-01

The main objective of this work is to investigate theoretically how tilting of an easy axis of a single-molecule magnet (SMM) from the orientation collinear with magnetic moments of the leads affects the switching process induced by current flowing through the system. To do this we consider a model system that consists of a SMM embedded in the nonmagnetic barrier of a magnetic tunnel junction. The anisotropy axis of the SMM forms an arbitrary angle with magnetic moments of the leads (the latt...

The legacy of care as reflexive learning.

Science.gov (United States)

García, Marta Rodríguez; Moya, Jose Luis Medina

2016-06-14

to analyze whether the tutor's use of reflexive strategies encourages the students to reflect. The goal is to discover what type of strategies can help to achieve this and how tutors and students behave in the practical context. a qualitative and ethnographic focus was adopted. Twenty-seven students and 15 tutors from three health centers participated. The latter had received specific training on reflexive clinical tutoring. The analysis was developed through constant comparisons of the categories. the results demonstrate that the tutors' use of reflexive strategies such as didactic questioning, didactic empathy and pedagogical silence contributes to encourage the students' reflection and significant learning. reflexive practice is key to tutors' training and students' learning. analisar se o uso de estratégias reflexivas por parte da tutora de estágio clínico estimula a reflexão nos estudantes. A intenção é descobrir qual tipo de estratégias podem ajudar a fazê-lo e como as tutoras e os estudantes se comportam no contexto prático. foi adotado um enfoque qualitativo de cunho etnográfico em que participaram 27 estudantes e 15 tutores de três centros de saúde que haviam recebido formação específica sobre tutoria clínica reflexiva. A análise foi realizada por meio de comparações constantes das categorias. os resultados demonstram que o uso de estratégias reflexivas como a interrogação didática, a empatia didática e o silêncio pedagógico por parte das tutoras, contribui para fomentar a reflexão do estudante e sua aprendizagem significativa. a prática reflexiva é a chave para a formação dos tutores e para a aprendizagem dos estudantes. analizar si el uso de estrategias reflexivas por parte de la tutora de prácticas clínicas fomenta la reflexión en los estudiantes. Se trata de conocer qué tipo de estrategias pueden ayudar a hacerlo y cómo se comportan tutoras y estudiantes en el contexto práctico. se ha utilizado un enfoque

The medial olivocochlear reflex in children during active listening.

Science.gov (United States)

Smith, Spencer B; Cone, Barbara

2015-08-01

To determine if active listening modulates the strength of the medial olivocochlear (MOC) reflex in children. Click-evoked otoacoustic emissions (CEOAEs) were recorded from the right ear in quiet and in four test conditions: one with contralateral broadband noise (BBN) only, and three with active listening tasks wherein attention was directed to speech embedded in contralateral BBN. Fifteen typically-developing children (ranging in age from 8 to14 years) with normal hearing. CEOAE levels were reduced in every condition with contralateral acoustic stimulus (CAS) when compared to preceding quiet conditions. There was an additional systematic decrease in CEOAE level with increased listening task difficulty, although this effect was very small. These CEOAE level differences were most apparent in the 8-18 ms region after click onset. Active listening may change the strength of the MOC reflex in children, although the effects reported here are very subtle. Further studies are needed to verify that task difficulty modulates the activity of the MOC reflex in children.

Single Canonical Model of Reflexive Memory and Spatial Attention

Science.gov (United States)

Patel, Saumil S.; Red, Stuart; Lin, Eric; Sereno, Anne B.

2015-01-01

Many neurons in the dorsal and ventral visual stream have the property that after a brief visual stimulus presentation in their receptive field, the spiking activity in these neurons persists above their baseline levels for several seconds. This maintained activity is not always correlated with the monkey’s task and its origin is unknown. We have previously proposed a simple neural network model, based on shape selective neurons in monkey lateral intraparietal cortex, which predicts the valence and time course of reflexive (bottom-up) spatial attention. In the same simple model, we demonstrate here that passive maintained activity or short-term memory of specific visual events can result without need for an external or top-down modulatory signal. Mutual inhibition and neuronal adaptation play distinct roles in reflexive attention and memory. This modest 4-cell model provides the first simple and unified physiologically plausible mechanism of reflexive spatial attention and passive short-term memory processes. PMID:26493949

Single Canonical Model of Reflexive Memory and Spatial Attention.

Science.gov (United States)

Patel, Saumil S; Red, Stuart; Lin, Eric; Sereno, Anne B

2015-10-23

Many neurons in the dorsal and ventral visual stream have the property that after a brief visual stimulus presentation in their receptive field, the spiking activity in these neurons persists above their baseline levels for several seconds. This maintained activity is not always correlated with the monkey's task and its origin is unknown. We have previously proposed a simple neural network model, based on shape selective neurons in monkey lateral intraparietal cortex, which predicts the valence and time course of reflexive (bottom-up) spatial attention. In the same simple model, we demonstrate here that passive maintained activity or short-term memory of specific visual events can result without need for an external or top-down modulatory signal. Mutual inhibition and neuronal adaptation play distinct roles in reflexive attention and memory. This modest 4-cell model provides the first simple and unified physiologically plausible mechanism of reflexive spatial attention and passive short-term memory processes.

A reflexive perspective in problem solving

OpenAIRE

Chio, José Angel; Álvarez, Aida; López, Margarita

2013-01-01

The objective of this paper is to favour the methodological process of reflexive analysis in problem solving in the general teaching methods that concentrates in strengthening the dimensional analysis, to gain a greater preparation of the students for the solution of mathematical problems.

Oriented Structure of Pentablock Copolymers Induced by Solution Extrusion

Science.gov (United States)

Harada, Tamotsu; Bates, Frank S.; Lodge, Timothy P.

2002-03-01

Highly oriented structure of a poly(styrene-co-butadiene) pentablock copolymer (Mw; 104,700 g/mol, weight percentage of polybutadiene blocks; 29 wt of concentrated solutions. The pentablock copolymer was dissolved into mixtures of toluene and heptane, and the polymer concentration ranged from 40 wt extrusion, the pentablock copolymer was solidified either by coagulation in methanol or by evaporation of the solvent. Interestingly, a highly oriented lamellar structure was confirmed through the small angle X-ray scattering over a specific range of heptane composition, which is a good solvent for polybutadiene, although the hexagonal cylinder morphology was identified for the melt sample. The transition from the oriented lamellar to highly oriented cylinder structure was observed by annealing the samples at temperatures above the glass transition temperature of polystyrene. Moreover, a transition from parallel to perpendicular orientation in the lamellar state was observed with an increase of the extrusion shear rate. A comparison between pentablock and triblock copolymers will be also discussed.

Primary reflex persistence in children with reading difficulties (dyslexia): a cross-sectional study.

Science.gov (United States)

McPhillips, Martin; Jordan-Black, Julie-Anne

2007-03-02

The primary reflex system emerges during fetal life and is inhibited during the first year after birth. Our aim was to examine the effects of persistence of this early neurological system on the attainment of core literacy skills in dyslexic and non-dyslexic poor readers. We assessed the prevalence of a persistent primary reflex in a cross-sectional, representative sample of children (n=739) aged 7-9 years old attending mainstream primary school in Northern Ireland using standardised educational tests, and a clinical diagnostic test for a primary reflex (the asymmetrical tonic neck reflex (ATNR)). Multiple regression analyses, involving all of the sample children, revealed that persistence of the ATNR was significantly predictive of attainments in reading (t=-8.34, pschooling, the attainment of core educational skills may be affected by the persistence of a brainstem mediated reflex system that should have been inhibited in the first year after birth. Furthermore, these findings suggest that dyslexia is not a distinct category of poor reading, and that it may be more valid to term all poor readers as dyslexic irrespective of IQ.

Cortical tremor: a variant of cortical reflex myoclonus.

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Ikeda, A; Kakigi, R; Funai, N; Neshige, R; Kuroda, Y; Shibasaki, H

1990-10-01

Two patients with action tremor that was thought to originate in the cerebral cortex showed fine shivering-like finger twitching provoked mainly by action and posture. Surface EMG showed relatively rhythmic discharge at a rate of about 9 Hz, which resembled essential tremor. However, electrophysiologic studies revealed giant somatosensory evoked potentials (SEPs) with enhanced long-loop reflex and premovement cortical spike by the jerk-locked averaging method. Treatment with beta-blocker showed no effect, but anticonvulsants such as clonazepam, valproate, and primidone were effective to suppress the tremor and the amplitude of SEPs. We call this involuntary movement "cortical tremor," which is in fact a variant of cortical reflex myoclonus.

The effects of team reflexivity on psychological well-being in manufacturing teams.

Science.gov (United States)

Chen, Jingqiu; Bamberger, Peter A; Song, Yifan; Vashdi, Dana R

2018-04-01

While the impact of team reflexivity (a.k.a. after-event-reviews, team debriefs) on team performance has been widely examined, we know little about its implications on other team outcomes such as member well-being. Drawing from prior team reflexivity research, we propose that reflexivity-related team processes reduce demands, and enhance control and support. Given the centrality of these factors to work-based strain, we posit that team reflexivity, by affecting these factors, may have beneficial implications on 3 core dimensions of employee burnout, namely exhaustion, cynicism, and inefficacy (reduced personal accomplishment). Using a sample of 469 unskilled manufacturing workers employed in 73 production teams in a Southern Chinese factory, we implemented a time lagged, quasi-field experiment, with half of the teams trained in and executing an end-of-shift team debriefing, and the other half assigned to a control condition and undergoing periodic postshift team-building exercises. Our findings largely supported our hypotheses, demonstrating that relative to team members assigned to the control condition, those assigned to the reflexivity condition experienced a significant improvement in all 3 burnout dimensions over time. These effects were mediated by control and support (but not demands) and amplified as a function of team longevity. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Crystal orientation dependent thermoelectric properties of highly oriented aluminum-doped zinc oxide thin films

KAUST Repository

Abutaha, Anas I.

2013-02-06

We demonstrate that the thermoelectric properties of highly oriented Al-doped zinc oxide (AZO) thin films can be improved by controlling their crystal orientation. The crystal orientation of the AZO films was changed by changing the temperature of the laser deposition process on LaAlO3 (100) substrates. The change in surface termination of the LaAlO3 substrate with temperature induces a change in AZO film orientation. The anisotropic nature of electrical conductivity and Seebeck coefficient of the AZO films showed a favored thermoelectric performance in c-axis oriented films. These films gave the highest power factor of 0.26 W m−1 K−1 at 740 K.

Swedish Massage and Abnormal Reflexes of Children with Spastic Cerebral Palsy

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Vida Alizad

2007-09-01

Full Text Available Objectives: Massage therapy is one of the most widely used complementary and alternative medicine therapies for children. This study was conducted to determine the effect of wedish massage on abnormal reflexes in children with spastic cerebral palsy (CP. Methods: This study was a single blind clinical trial conducted on forty children with spastic CP who were recruited from clinics of the University of Social Welfare & Rehabilitation Sciences. They were randomly assigned to intervention and control groups. The routine occupational therapy (OT techniques were performed during a 3 month-period in both groups. The intervention group also received Swedish massage for 30 minutes before every OT session. Primary, spinal, brain stem, midbrain, cortical and automatic reflexes were evaluated at the beginning of the study and 3 months later. The data analysis was done by parametric and nonparametric tests. Results: Finally, thirteen subjects in the intervention group and 14 subjects in the control group were remained and studied. The average ages in the intervention and control groups were 49.5 and 42.1 months respectively. There were no statistically significant differences in abnormal reflexes in the intervention group in comparison to the control (P>0.05. Discussion: Adding Swedish massage to traditional OT techniques had no significant effects on abnormal reflexes in children with spastic cerebral palsy. Evidently more research is required in order to completely reject the effects of Swedish massage on abnormal reflexes of children with CP.

Structure, deformation, and failure of flow-oriented semicrystalline polymers

NARCIS (Netherlands)

Schrauwen, B.A.G.; Breemen, van L.C.A.; Spoelstra, A.B.; Govaert, L.E.; Peters, G.W.M.; Meijer, H.E.H.

2004-01-01

This study deals with the influence of processing induced crystalline orientation on the macroscopic deformation and failure behavior of thin samples of polyethylene and polypropylene. Distribution and structure of flow-induced orientations were characterized by optical microscopy, X-ray diffraction

The primary visual cortex in the neural circuit for visual orienting

Science.gov (United States)

Zhaoping, Li

The primary visual cortex (V1) is traditionally viewed as remote from influencing brain's motor outputs. However, V1 provides the most abundant cortical inputs directly to the sensory layers of superior colliculus (SC), a midbrain structure to command visual orienting such as shifting gaze and turning heads. I will show physiological, anatomical, and behavioral data suggesting that V1 transforms visual input into a saliency map to guide a class of visual orienting that is reflexive or involuntary. In particular, V1 receives a retinotopic map of visual features, such as orientation, color, and motion direction of local visual inputs; local interactions between V1 neurons perform a local-to-global computation to arrive at a saliency map that highlights conspicuous visual locations by higher V1 responses. The conspicuous location are usually, but not always, where visual input statistics changes. The population V1 outputs to SC, which is also retinotopic, enables SC to locate, by lateral inhibition between SC neurons, the most salient location as the saccadic target. Experimental tests of this hypothesis will be shown. Variations of the neural circuit for visual orienting across animal species, with more or less V1 involvement, will be discussed. Supported by the Gatsby Charitable Foundation.

Computer simulation model of reflex e-beam systems coupled to an external circuit

International Nuclear Information System (INIS)

Jungwirth, K.; Stavinoha, P.

1982-01-01

Dynamics of ions and relativistic electrons in various high-voltage reflexing systems (reflex diodes and triodes) was investigated numerically by means of 1 1/2-dimensional PIC simulation model OREBIA. Its perfected version OREBIA-REX also accounts for system coupling to an external power source circuit, thus yielding the currents and applied voltage self-consistently. Various modes of operation of reflex diode and triode were studied using both models. It is shown that neglecting the influence of the external circuit can lead to seve--re overestimation of both ion currents and electron accumulation rates. In coupled systems with ions repeated collapses of impedance due to electron-ion relaxation processes are observed. The current and voltage pulses calculated for several reflex diodes and triodes with and without ions are presented. (J.U.)

Effects of intrathecal or intracerebroventricular administration of nonsteroidal anti-inflammatory drugs on a C-fiber reflex in rats.

Science.gov (United States)

Bustamante, D; Paeile, C; Willer, J C; Le Bars, D

1997-06-01

A C-fiber reflex elicited by electrical stimulation within the territory of the sural nerve was recorded from the ipsilateral biceps femoris muscle in anesthetized rats. The temporal evolution of the response was studied using a constant stimulus intensity (3 times threshold), and recruitment curves were built by varying the stimulus intensity from 0 to 7 times threshold. The intrathecal (i.t.) but not i.c.v. administration of aspirin, indomethacin, ketoprofen and lysine clonixinate resulted in dose-dependent depressions of the C-fiber reflex. In contrast, saline was ineffective. Regardless of the route of administration, the drugs never produced disturbances in heart rate and/or acid-base equilibrium. When a constant level of stimulation was used, 500 microg of aspirin i.t. induced a blockade of the reflex immediately after the injection, followed by a partial recovery. Indomethacin produced a stable depression, which reached 80 to 90% with an i.t. dose of 500 microg. Ketoprofen and lysine clonixinate produced a more stable effect; the highest doses (500 microg) produced a steady-state depression of approximately 50% for approximately 30 min. When the recruitment curves were built with a range of nociceptive stimulus intensities, all of the drugs except for indomethacin produced a dose-dependent decrease in the slopes and the areas under the recruitment curves without major modifications in the thresholds; indomethacin also induced a significant dose-related increase in the threshold. The orders of potency for both stimulation paradigms with the i.t. route were the same, namely aspirin > indomethacin > lysine clonixinate > or = ketoprofen. It is concluded that nonsteroidal anti-inflammatory drugs elicit significant antinociceptive effects at a spinal level, which do not depend on the existence of a hyperalgesic or inflammatory state. Such effects were not seen after injections within the lateral ventricle.

Exogenous orienting of attention depends upon the ability to execute eye movements.

Science.gov (United States)

Smith, Daniel T; Rorden, Chris; Jackson, Stephen R

2004-05-04

Shifts of attention can be made overtly by moving the eyes or covertly with attention being allocated to a region of space that does not correspond to the current direction of gaze. However, the precise relationship between eye movements and the covert orienting of attention remains controversial. The influential premotor theory proposes that the covert orienting of attention is produced by the programming of (unexecuted) eye movements and thus predicts a strong relationship between the ability to execute eye movements and the operation of spatial attention. Here, we demonstrate for the first time that impaired spatial attention is observed in an individual (AI) who is neurologically healthy but who cannot execute eye movements as a result of a congenital impairment in the elasticity of her eye muscles. This finding provides direct support for the role of the eye-movement system in the covert orienting of attention and suggests that whereas intact cortical structures may be necessary for normal attentional reflexes, they are not sufficient. The ability to move our eyes is essential for the development of normal patterns of spatial attention.

Reflexive journaling on emotional research topics: ethical issues for team researchers.

Science.gov (United States)

Malacrida, Claudia

2007-12-01

Traditional epistemological concerns in qualitative research focus on the effects of researchers' values and emotions on choices of research topics, power relations with research participants, and the influence of researcher standpoints on data collection and analysis. However, the research process also affects the researchers' values, emotions, and standpoints. Drawing on reflexive journal entries of assistant researchers involved in emotionally demanding team research, this article explores issues of emotional fallout for research team members, the implications of hierarchical power imbalances on research teams, and the importance of providing ethical opportunities for reflexive writing about the challenges of doing emotional research. Such reflexive approaches ensure the emotional safety of research team members and foster opportunities for emancipatory consciousness among research team members.

Short-term locomotor adaptation to a robotic ankle exoskeleton does not alter soleus Hoffmann reflex amplitude.

Science.gov (United States)

Kao, Pei-Chun; Lewis, Cara L; Ferris, Daniel P

2010-07-26

To improve design of robotic lower limb exoskeletons for gait rehabilitation, it is critical to identify neural mechanisms that govern locomotor adaptation to robotic assistance. Previously, we demonstrated soleus muscle recruitment decreased by approximately 35% when walking with a pneumatically-powered ankle exoskeleton providing plantar flexor torque under soleus proportional myoelectric control. Since a substantial portion of soleus activation during walking results from the stretch reflex, increased reflex inhibition is one potential mechanism for reducing soleus recruitment when walking with exoskeleton assistance. This is clinically relevant because many neurologically impaired populations have hyperactive stretch reflexes and training to reduce the reflexes could lead to substantial improvements in their motor ability. The purpose of this study was to quantify soleus Hoffmann (H-) reflex responses during powered versus unpowered walking. We tested soleus H-reflex responses in neurologically intact subjects (n=8) that had trained walking with the soleus controlled robotic ankle exoskeleton. Soleus H-reflex was tested at the mid and late stance while subjects walked with the exoskeleton on the treadmill at 1.25 m/s, first without power (first unpowered), then with power (powered), and finally without power again (second unpowered). We also collected joint kinematics and electromyography. When the robotic plantar flexor torque was provided, subjects walked with lower soleus electromyographic (EMG) activation (27-48%) and had concomitant reductions in H-reflex amplitude (12-24%) compared to the first unpowered condition. The H-reflex amplitude in proportion to the background soleus EMG during powered walking was not significantly different from the two unpowered conditions. These findings suggest that the nervous system does not inhibit the soleus H-reflex in response to short-term adaption to exoskeleton assistance. Future studies should determine if the

How Can Hypnodontics Manage Severe Gag Reflex for Root Canal Therapy? A Case Report

Science.gov (United States)

Ramazani, Mohsen; zarenejad, Nafiseh; Parirokh, Masoud; Zahedpasha, Samir

2016-01-01

In endodontics, severe involuntary gagging can have a severe impact on treatment procedure. There are many ways to ease the gag reflex, one of which is hypnosis. A 34-year-old male was referred for root canal treatment of a molar tooth. He had not received any dental treatments for the past nine years due to fear of severe gag reflex. Three hypnotic sessions based upon eye fixation, progressive muscle relaxation and guided imagery techniques were spent for psychosomatic management. The gag reflex was controlled and reduced to a normal level, and the required dental treatments including root canal therapy and restoration were performed successfully. This report shows that hypnosis can control gag reflex for dental treatments. PMID:27141226

Visual orienting and attention deficits in 5- and 10-month-old preterm infants.

Science.gov (United States)

Ross-Sheehy, Shannon; Perone, Sammy; Macek, Kelsi L; Eschman, Bret

2017-02-01

Cognitive outcomes for children born prematurely are well characterized, including increased risk for deficits in memory, attention, processing speed, and executive function. However, little is known about deficits that appear within the first 12 months, and how these early deficits contribute to later outcomes. To probe for functional deficits in visual attention, preterm and full-term infants were tested at 5 and 10 months with the Infant Orienting With Attention task (IOWA; Ross-Sheehy, Schneegans and Spencer, 2015). 5-month-old preterm infants showed significant deficits in orienting speed and task related error. However, 10-month-old preterm infants showed only selective deficits in spatial attention, particularly reflexive orienting responses, and responses that required some inhibition. These emergent deficits in spatial attention suggest preterm differences may be related to altered postnatal developmental trajectories. Moreover, we found no evidence of a dose-response relation between increased gestational risk and spatial attention. These results highlight the critical role of postnatal visual experience, and suggest that visual orienting may be a sensitive measure of attentional delay. Results reported here both inform current theoretical models of early perceptual/cognitive development, and future intervention efforts. Copyright © 2016 Elsevier Inc. All rights reserved.

Educational Strategies to Enhance Reflexivity Among Clinicians and Health Professional Students: A Scoping Study

Directory of Open Access Journals (Sweden)

Rachel Landy

2016-09-01

Full Text Available Reflexivity involves the ability to understand how one's social locations and experiences of advantage or disadvantage have shaped the way one understands the world. The capacity for reflexivity is crucial because it informs clinical decisions, which can lead to improvements in service delivery and patient outcomes. In this article, we present a scoping study that explored educational strategies designed to enhance reflexivity among clinicians and/or health profession students. We reviewed articles and grey literature that address the question: What is known about strategies for enhancing reflexivity among clinicians and students in health professional training programs? We searched multiple databases using keywords including: reflexivity, reflective, allied health professionals, pedagogy, learning, and education. The search strategy was iterative and involved three reviews. Each abstract was independently reviewed by two team members. Sixty-eight texts met the inclusion criteria. There was great diversity among the educational strategies and among health professions. Commonalities across strategies were identified related to reflective writing, experiential learning, classroom-based activities, continuing education, and online learning. We also summarize the 19 texts that evaluated educational strategies to enhance reflexivity. Further research and education is urgently needed for more equitable and socially-just health care. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1603140

The Reflexive Nature of Reading as Ethnographic Practice: Editorial Note

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Wolff-Michael Roth

2004-01-01

Full Text Available In this editorial, I suggest that not only is reading published texts a way of doing ethno­graph­ic research, but also reading concretely realizes itself in the productions of new texts that reproduce the cultural practices that are analyzed in the published text. Reading as ethnographic method is therefore a reflexive project. I provide a dialectical framework for theorizing the reflexive nature of reading. URN: urn:nbn:de:0114-fqs0401390

Reflex control of the spine and posture: a review of the literature from a chiropractic perspective

Directory of Open Access Journals (Sweden)

Schlappi Mark

2005-08-01

Full Text Available Abstract Objective This review details the anatomy and interactions of the postural and somatosensory reflexes. We attempt to identify the important role the nervous system plays in maintaining reflex control of the spine and posture. We also review, illustrate, and discuss how the human vertebral column develops, functions, and adapts to Earth's gravity in an upright position. We identify functional characteristics of the postural reflexes by reporting previous observations of subjects during periods of microgravity or weightlessness. Background Historically, chiropractic has centered around the concept that the nervous system controls and regulates all other bodily systems; and that disruption to normal nervous system function can contribute to a wide variety of common ailments. Surprisingly, the chiropractic literature has paid relatively little attention to the importance of neurological regulation of static upright human posture. With so much information available on how posture may affect health and function, we felt it important to review the neuroanatomical structures and pathways responsible for maintaining the spine and posture. Maintenance of static upright posture is regulated by the nervous system through the various postural reflexes. Hence, from a chiropractic standpoint, it is clinically beneficial to understand how the individual postural reflexes work, as it may explain some of the clinical presentations seen in chiropractic practice. Method We performed a manual search for available relevant textbooks, and a computer search of the MEDLINE, MANTIS, and Index to Chiropractic Literature databases from 1970 to present, using the following key words and phrases: "posture," "ocular," "vestibular," "cervical facet joint," "afferent," "vestibulocollic," "cervicocollic," "postural reflexes," "spaceflight," "microgravity," "weightlessness," "gravity," "posture," and "postural." Studies were selected if they specifically tested any or

Parasympathetic Nervous System Dysfunction, as Identified by Pupil Light Reflex, and Its Possible Connection to Hearing Impairment.

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Yang Wang

Full Text Available Although the pupil light reflex has been widely used as a clinical diagnostic tool for autonomic nervous system dysfunction, there is no systematic review available to summarize the evidence that the pupil light reflex is a sensitive method to detect parasympathetic dysfunction. Meanwhile, the relationship between parasympathetic functioning and hearing impairment is relatively unknown.To 1 review the evidence for the pupil light reflex being a sensitive method to evaluate parasympathetic dysfunction, 2 review the evidence relating hearing impairment and parasympathetic activity and 3 seek evidence of possible connections between hearing impairment and the pupil light reflex.Literature searches were performed in five electronic databases. All selected articles were categorized into three sections: pupil light reflex and parasympathetic dysfunction, hearing impairment and parasympathetic activity, pupil light reflex and hearing impairment.Thirty-eight articles were included in this review. Among them, 36 articles addressed the pupil light reflex and parasympathetic dysfunction. We summarized the information in these data according to different types of parasympathetic-related diseases. Most of the studies showed a difference on at least one pupil light reflex parameter between patients and healthy controls. Two articles discussed the relationship between hearing impairment and parasympathetic activity. Both studies reported a reduced parasympathetic activity in the hearing impaired groups. The searches identified no results for pupil light reflex and hearing impairment.As the first systematic review of the evidence, our findings suggest that the pupil light reflex is a sensitive tool to assess the presence of parasympathetic dysfunction. Maximum constriction velocity and relative constriction amplitude appear to be the most sensitive parameters. There are only two studies investigating the relationship between parasympathetic activity and hearing

Parasympathetic Nervous System Dysfunction, as Identified by Pupil Light Reflex, and Its Possible Connection to Hearing Impairment.

Science.gov (United States)

Wang, Yang; Zekveld, Adriana A; Naylor, Graham; Ohlenforst, Barbara; Jansma, Elise P; Lorens, Artur; Lunner, Thomas; Kramer, Sophia E

2016-01-01

Although the pupil light reflex has been widely used as a clinical diagnostic tool for autonomic nervous system dysfunction, there is no systematic review available to summarize the evidence that the pupil light reflex is a sensitive method to detect parasympathetic dysfunction. Meanwhile, the relationship between parasympathetic functioning and hearing impairment is relatively unknown. To 1) review the evidence for the pupil light reflex being a sensitive method to evaluate parasympathetic dysfunction, 2) review the evidence relating hearing impairment and parasympathetic activity and 3) seek evidence of possible connections between hearing impairment and the pupil light reflex. Literature searches were performed in five electronic databases. All selected articles were categorized into three sections: pupil light reflex and parasympathetic dysfunction, hearing impairment and parasympathetic activity, pupil light reflex and hearing impairment. Thirty-eight articles were included in this review. Among them, 36 articles addressed the pupil light reflex and parasympathetic dysfunction. We summarized the information in these data according to different types of parasympathetic-related diseases. Most of the studies showed a difference on at least one pupil light reflex parameter between patients and healthy controls. Two articles discussed the relationship between hearing impairment and parasympathetic activity. Both studies reported a reduced parasympathetic activity in the hearing impaired groups. The searches identified no results for pupil light reflex and hearing impairment. As the first systematic review of the evidence, our findings suggest that the pupil light reflex is a sensitive tool to assess the presence of parasympathetic dysfunction. Maximum constriction velocity and relative constriction amplitude appear to be the most sensitive parameters. There are only two studies investigating the relationship between parasympathetic activity and hearing impairment

Factitious lymphoedema as a psychiatric condition mimicking reflex sympathetic dystrophy: a case report

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Nwaejike Nnamdi

2008-06-01

Full Text Available Abstract Introduction Reflex sympathetic dystrophy can result in severe disability with only one in five patients able to fully resume prior activities. Therefore, it is important to diagnose this condition early and begin appropriate treatment. Factitious lymphoedema can mimic reflex sympathetic dystrophy and is caused by self-inflicted tourniquets, blows to the arm or repeated skin irritation. Patients with factitious lymphoedema have an underlying psychiatric disorder but usually present to emergency or orthopaedics departments. Factitious lymphoedema can then be misdiagnosed as reflex sympathetic dystrophy. The treatment for factitious lymphoedema is dealing with the underlying psychiatric condition. Case presentation We share our experience of treating a 33-year-old man, who presented with factitious lymphoedema, initially diagnosed as reflex sympathetic dystrophy. Conclusion Awareness of this very similar differential diagnosis allows early appropriate treatment to be administered.

Peripheral δ-opioid receptors attenuate the exercise pressor reflex.

Science.gov (United States)

Leal, Anna K; Yamauchi, Katsuya; Kim, Joyce; Ruiz-Velasco, Victor; Kaufman, Marc P

2013-10-15

In rats with ligated femoral arteries, the exercise pressor reflex is exaggerated, an effect that is attenuated by stimulation of peripheral μ-opioid receptors on group IV metabosensitive afferents. In contrast, δ-opioid receptors are expressed mostly on group III mechanosensitive afferents, a finding that prompted us to determine whether stimulation of these opioid receptors could also attenuate the exaggerated exercise pressor reflex in "ligated" rats. We found femoral arterial injection of [D-Pen2,D-Pen5]enkephalin (DPDPE; 1.0 μg), a δ-opioid agonist, significantly attenuated the pressor and cardioaccelerator components of the exercise pressor reflex evoked by hindlimb muscle contraction in both rats with ligated and patent femoral arteries. DPDPE significantly decreased the pressor responses to muscle mechanoreflex activation, evoked by tendon stretch, in ligated rats only. DPDPE (1.0 μg) had no effect in either group on the pressor and cardioaccelerator responses to capsaicin (0.2 μg), which primarily stimulates group IV afferents. DPDPE (1.0 μg) had no effect on the pressor and cardioaccelerator responses to lactic acid (24 mM), which stimulates group III and IV afferents, in rats with patent femoral arteries but significantly decreased the pressor response in ligated rats. Western blots revealed the amount of protein comprising the δ-opioid receptor was greater in dorsal root ganglia innervating hindlimbs with ligated femoral arteries than in dorsal root ganglia innervating hindlimbs with patent femoral arteries. Our findings support the hypothesis that stimulation of δ-opioid receptors on group III afferents attenuated the exercise pressor reflex.

Team performance in the Italian NHS: the role of reflexivity.

Science.gov (United States)

Urbini, Flavio; Callea, Antonino; Chirumbolo, Antonio; Talamo, Alessandra; Ingusci, Emanuela; Ciavolino, Enrico

2018-04-09

Purpose The purpose of this paper is twofold: first, to investigate the goodness of the input-process-output (IPO) model in order to evaluate work team performance within the Italian National Health Care System (NHS); and second, to test the mediating role of reflexivity as an overarching process factor between input and output. Design/methodology/approach The Italian version of the Aston Team Performance Inventory was administered to 351 employees working in teams in the Italian NHS. Mediation analyses with latent variables were performed via structural equation modeling (SEM); the significance of total, direct, and indirect effect was tested via bootstrapping. Findings Underpinned by the IPO framework, the results of SEM supported mediational hypotheses. First, the application of the IPO model in the Italian NHS showed adequate fit indices, showing that the process mediates the relationship between input and output factors. Second, reflexivity mediated the relationship between input and output, influencing some aspects of team performance. Practical implications The results provide useful information for HRM policies improving process dimensions of the IPO model via the mediating role of reflexivity as a key role in team performance. Originality/value This study is one of a limited number of studies that applied the IPO model in the Italian NHS. Moreover, no study has yet examined the role of reflexivity as a mediator between input and output factors in the IPO model.

Cannabinoid-induced effects on the nociceptive system: a neurophysiological study in patients with secondary progressive multiple sclerosis.

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Conte, Antonella; Bettolo, Chiara Marini; Onesti, Emanuela; Frasca, Vittorio; Iacovelli, Elisa; Gilio, Francesca; Giacomelli, Elena; Gabriele, Maria; Aragona, Massimiliano; Tomassini, Valentina; Pantano, Patrizia; Pozzilli, Carlo; Inghilleri, Maurizio

2009-05-01

Although clinical studies show that cannabinoids improve central pain in patients with multiple sclerosis (MS) neurophysiological studies are lacking to investigate whether they also suppress these patients' electrophysiological responses to noxious stimulation. The flexion reflex (FR) in humans is a widely used technique for assessing the pain threshold and for studying spinal and supraspinal pain pathways and the neurotransmitter system involved in pain control. In a randomized, double-blind, placebo-controlled, cross-over study we investigated cannabinoid-induced changes in RIII reflex variables (threshold, latency and area) in a group of 18 patients with secondary progressive MS. To investigate whether cannabinoids act indirectly on the nociceptive reflex by modulating lower motoneuron excitability we also evaluated the H-reflex size after tibial nerve stimulation and calculated the H wave/M wave (H/M) ratio. Of the 18 patients recruited and randomized 17 completed the study. After patients used a commercial delta-9-tetrahydrocannabinol (THC) and cannabidiol mixture as an oromucosal spray the RIII reflex threshold increased and RIII reflex area decreased. The visual analogue scale score for pain also decreased, though not significantly. Conversely, the H/M ratio measured before patients received cannabinoids remained unchanged after therapy. In conclusion, the cannabinoid-induced changes in the RIII reflex threshold and area in patients with MS provide objective neurophysiological evidence that cannabinoids modulate the nociceptive system in patients with MS.

Medial olivocochlear reflex interneurons are located in the posteroventral cochlear nucleus: a kainic acid lesion study in guinea pigs.

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de Venecia, Ronald K; Liberman, M Charles; Guinan, John J; Brown, M Christian

2005-07-11

The medial olivocochlear (MOC) reflex arc is probably a three-neuron pathway consisting of type I spiral ganglion neurons, reflex interneurons in the cochlear nucleus, and MOC neurons that project to the outer hair cells of the cochlea. We investigated the identity of MOC reflex interneurons in the cochlear nucleus by assaying their regional distribution using focal injections of kainic acid. Our reflex metric was the amount of change in the distortion product otoacoustic emission (at 2f(1)-f(2)) just after onset of the primary tones. This metric for MOC reflex strength has been shown to depend on an intact reflex pathway. Lesions involving the posteroventral cochlear nucleus (PVCN), but not the other subdivisions, produced long-term decreases in MOC reflex strength. The degree of cell loss within the dorsal part of the PVCN was a predictor of whether the lesion affected MOC reflex strength. We suggest that multipolar cells within the PVCN have the distribution and response characteristics appropriate to be the MOC reflex interneurons. (c) 2005 Wiley-Liss, Inc.

Two Reflexivities in Current Social Science: Remarks on an Absent Debate

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Andreas Langenohl

2009-02-01

Full Text Available This paper traces and compares two different uses of the category of reflexivity in contemporary methodological debates in the social sciences. While a first use is strongly influenced by the textual turn in cultural anthropology, a second use is aligned with Pierre BOURDIEU's notion of "scientific reflexivity." Whereas the first use postulates an epistemological break with scientific modernity and argues for a perpetual contextualization and interrelation of research results and methods, BOURDIEU defends sociology’s claim of objectivity, which, according to him, can be redeemed through a reflexive objectification of sociological practice. Up to the present these two uses have existed in almost complete isolation from each other. They represent alternating reactions to, and reconstructions and translations of, poststructuralism and postmodernism in the social sciences. URN: urn:nbn:de:0114-fqs090297

Danish Working Environment Regulation. How reflexive - how political? -a Scandinavian case

DEFF Research Database (Denmark)

Koch, Christian

an understanding of the directions of the reforms made in this period. The paper operate with two analytical perspectives: The reflexive regulation perspective and the political process perspective. Danish working environment regulation is discussed through the general political initiatives taken, and through four...... specific regulation topics: The Occupational Health Services (OHS), regulation of the psychological working environment, the 'Monotonous Repeated Work'-plan and the workers' compensation. Taking the last twenty years' development as a whole the main developments in the regulation is a further shift...... in balance between material and reflexive regulation elements to the benefit of the latter. But although the reflexive elements seem to stabilize, they are vulnerable to a loss of legitimacy and changes in the political pattern.The impact on enterprise power patterns is summed up in a polarization thesis...

Reflexive Aero Structures for Enhanced Survivability, Phase II

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National Aeronautics and Space Administration — Cornerstone Research Group Inc. (CRG) will develop an advanced reflexive structure technology system to increase the survivability of future systems constructed of...

On reflexivity and the conduct of the self in everyday life: reflections on Bourdieu and Archer.

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Akram, Sadiya; Hogan, Anthony

2015-12-01

This article provides a critique of the concept of reflexivity in social theory today and argues against the tendency to define agency exclusively in terms of reflexivity. Margaret Archer, in particular, is highlighted as a key proponent of this thesis. Archer argues that late modernity is characterized by reflexivity but, in our view, this position neglects the impact of more enduring aspects of agency, such as the routinization of social life and the role of the taken-for-granted. These concepts were pivotal to Bourdieu and Giddens' theorization of everyday life and action and to Foucault's understanding of technologies of the self. We offer Bourdieu's habitus as a more nuanced approach to theorizing agency, and provide an alternative account of reflexivity. Whilst accepting that reflexivity is a core aspect of agency, we argue that it operates to a backdrop of the routinization of social life and operates from within and not outside of habitus. We highlight the role of the breach in reflexivity, suggesting that it opens up a critical window for agents to initiate change. The article suggests caution in over-ascribing reflexivity to agency, instead arguing that achieving reflexivity and change is a difficult and fraught process, which has emotional and moral consequences. The effect of this is that people often prefer the status quo, rather than to risk change and uncertainty. © London School of Economics and Political Science 2015.

Diagnostic utility of the acoustic reflex in predicting hearing in paediatric populations.

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Pérez-Villa, Yolanda E; Mena-Ramírez, María E; Aguirre, Laura E Chamlati; Mora-Magaña, Ignacio; Gutiérrez-Farfán, Ileana S

2014-01-01

The sensitivity of prediction of acoustic reflex, in determining the level of hearing loss, is especially useful in paediatric populations. It is based on the difference between the pure tone stapedius reflex threshold and contralateral white noise. The white noise threshold was 60 dB and that of pure tone was 80 dB. Our objective was to determine the diagnostic sensitivity of the prediction of the acoustic reflex. We studied children aged <10 years, from October 2011 to May 2012, by measuring the acoustic reflex with white noise and pure tone. We used contrast tests, with X2 and student t-test. Concordance was measured with Kappa. Results were considered significant at P≤.05. Our protocol was approved by Institutional Ethics Committee. Informed consent was obtained from the parents in all cases. Prediction of normal hearing was 0.84 for the right ear and 0.78 in left ear, while for hearing loss of an unspecified grade, it was 0.98 for the right ear and 0.96 in the left ear. Kappa value was 0.7 to 0.6 for the right ear and left ear. The acoustic reflex is of little diagnostic utility in predicting the degree of hearing loss, but it predicts more than 80% of normal hearing. The clinical utility of the reflex is indisputable, as it is an objective method, simple and rapid to use, that can be performed from birth and whose results are independent of the cooperation and willingness of the subject. It is proposed as an obligatory part of hearing screening. Copyright © 2013 Elsevier España, S.L.U. y Sociedad Española de Otorrinolaringología y Patología Cérvico-Facial. All rights reserved.

Does diurnal variation in cough reflex testing exist in healthy young adults?

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Perry, Sarah; Huckabee, Maggie-Lee

2017-05-01

The aim of this study was to investigate whether diurnal variation in cough reflex sensitivity exists in healthy young adults when a tidal-breathing method is used. Fifty-three participants (19-37 years) underwent cough reflex testing on two occasions: once in the morning (between 9 am - midday) and once in the afternoon (between 2-5 pm). The order of testing was counter-balanced. Within each assessment, participants inhaled successively higher citric acid concentrations via a facemask, with saline solution randomly interspersed to control for a placebo response. The lowest concentration that elicited a reflexive cough response was recorded. Morning cough thresholds (mean=0.6mol/L) were not different from afternoon cough thresholds (mean=0.6mol/L), p=0.16, T=101, r=-0.14. We found no evidence of diurnal variability in cough reflex testing. There was, however, an order effect irrespective of time of day, confirming that healthy participants are able to volitionally modulate their cough response. Copyright © 2017 Elsevier B.V. All rights reserved.

Radiation-Induced Organizing Pneumonia: A Characteristic Disease that Requires Symptom-Oriented Management.

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Otani, Keisuke; Seo, Yuji; Ogawa, Kazuhiko

2017-01-27

Radiation-induced organizing pneumonia (RIOP) is an inflammatory lung disease that is occasionally observed after irradiation to the breast. It is a type of secondary organizing pneumonia that is characterized by infiltrates outside the irradiated volume that are sometimes migratory. Corticosteroids work acutely, but relapse of pneumonia is often experienced. Management of RIOP should simply be symptom-oriented, and the use of corticosteroids should be limited to severe symptoms from the perspective not only of cost-effectiveness but also of cancer treatment. Once steroid therapy is started, it takes a long time to stop it due to frequent relapses. We review RIOP from the perspective of its diagnosis, epidemiology, molecular pathogenesis, and patient management.

Prognostic Value of Impaired Preoperative Ankle Reflex in Surgical Outcome of Lumbar Disc Herniation

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Farzad Omidi-Kashani

2016-01-01

Full Text Available Background: Several prognostic factors exist influencing the outcome of surgical discectomy in the patients with lumbar disc herniation (LDH. The aim of this study is to evaluate the relationship between severity of preoperative impaired ankle reflex and outcomes of lumbar discectomy in the patients with L5-S1 LDH. Methods: We retrospectively evaluated 181 patients (108 male and 73 female who underwent simple discectomy in our orthopedic department from April 2009 to April 2013 and followed them up for more than one year. The mean age of the patients was 35.3±8.9 years old. Severity of reflex impairment was graded from 0 to 4+ and radicular pain and disability were assessed by visual analogue scale (VAS and Oswestry disability index (ODI questionnaires, respectively. Subjective satisfaction was also evaluated at the last follow-up visit. Chi-square and Kruskal-Wallis tests were used to compare qualitative variables. Results: Reflex impairment existed in 44.8% preoperatively that improved to 10% at the last follow-up visit. Statistical analyses could not find a significant relationship between the severity of impaired ankle reflex and sex or age (P=0.538 and P=0.709, respectively. There was a remarkable relationship between severity of reflex impairment and preoperative radicular pain or disability (P=0.012 and P=0.002, respectively. Kruskal-Wallis test showed that a more severity in ankle reflex impairment was associated with not only less improvement in postoperative pain and disability but also less satisfaction rate (P Conclusions: In the patients with L5-S1 LDH, more severe ankle reflex impairment is associated with less improvement in postoperative pain, disability, and subjective satisfaction.

Distributed Dynamic Traffic Modeling and Implementation Oriented Different Levels of Induced Travelers

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Yan Liu

2015-01-01

Full Text Available In order to respond to the variable state of traffic network in time, a distributed dynamic traffic assignment strategy is proposed which can improve the intelligent traffic management. The proposed dynamic assignment method is based on utility theory and is oriented to different levels of induced users. A distributed model based on the marginal utility is developed which combines the advantages of both decentralized paradigm and traveler preference, so as to provide efficient and robust dynamic traffic assignment solutions under uncertain network conditions. Then, the solution algorithm including subroute update and subroute calculation is proposed. To testify the effectiveness of the proposed model in optimizing traffic network operation and minimizing traveler’s cost on different induced levels, a sequence numerical experiment is conducted. In the experiment, there are two test environments: one is in different network load conditions and the other is in different deployment coverage of local agents. The numerical results show that the proposed model not only can improve the running efficiency of road network but also can significantly decrease the average travel time.

Evaluating Red Reflex and Surgeon Preference Between Nearly-Collimated and Focused Beam Microscope Illumination Systems.

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Cionni, Robert J; Pei, Ron; Dimalanta, Ramon; Lubeck, David

2015-08-01

To evaluate the intensity and stability of the red reflex produced by ophthalmic surgical microscopes with nearly-collimated versus focused illumination systems and to assess surgeon preference in a simulated surgical setting. This two-part evaluation consisted of postproduction surgical video analysis of red reflex intensity and a microscope use and preference survey completed by 13 experienced cataract surgeons. Survey responses were based on bench testing and experience in a simulated surgical setting. A microscope with nearly-collimated beam illumination and two focused beam microscopes were assessed. Red reflex intensity and stability were greater with the nearly-collimated microscope illumination system. In the bench testing survey, surgeons reported that the red reflex was maintained over significantly greater distances away from pupillary center, and depth of focus was numerically greater with nearly-collimated illumination relative to focused illumination. Most participating surgeons (≥64%) reported a preference for the microscope with nearly-collimated illumination with regard to red reflex stability, depth of focus, visualization, surgical working distance, and perceived patient comfort. The microscope with nearly-collimated illumination produced a more intense and significantly more stable red reflex and was preferred overall by more surgeons. This is the first report of an attempt to quantify red reflex intensity and stability and to evaluate surgically-relevant parameters between microscope systems. The data and methods presented here may provide a basis for future studies attempting to quantify differences between surgical microscopes that may affect surgeon preference and microscope use in ophthalmic surgery.

Plantar reflex excitability is increased in the evening in restless legs syndrome patients.

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Dafkin, Chloe; Green, Andrew; Olivier, Benita; McKinon, Warrick; Kerr, Samantha

2017-11-01

To investigate if diurnal changes in spinal excitability (plantar reflex) occur in restless legs syndrome (RLS) participants compared to healthy matched controls. Thirteen RLS participants and 13 healthy control participants' plantar reflex responses were evaluated in the evening (PM) and the morning (AM). Plantar reflex responses were assessed electromyographically, using motion analysis (kinematically) and by subjective nociception (Visual Analogue Scale). RLS participants showed a circadian variation in plantar reflex responses whilst control participants did not. Evening ankle angle changes were larger and faster in RLS participants compared to morning responses. In addition RLS participants displayed significantly smaller change in ankle angle and significantly slower ankle movements in the evening and the morning as well as significantly lower lateral gastrocnemius maximum amplitude in the compared to control participants. The findings of the current study support the theory of RLS circadian fluctuations in spinal excitability. An unexpected finding was decreased plantar reflex responses in RLS participants compared to healthy control participants. However this finding supports the theory of mechanical hypoesthesia in RLS. The results of this study provide further insight into the pathophysiology of RLS, highlighting that not all sensory processing is affected in the same manner. Copyright © 2017 Elsevier B.V. All rights reserved.

A Study on the Effects of Bee Venom Aqua-Acupuncture on Writhing Reflex

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Jeong Sun-Hee

2000-07-01

Full Text Available Introduction:In spite of the use of Bee Venom aqua-acupuncture in the clinics, the scientific evaluation on effects is not enough. Bee Venom aqua-acupuncture is used according to the stimulation of acupuncture point and the chemical effects of Bee Venom. The aims of this study is to investigate the analgegic effects of the Bee Venom aqua-acupuncture, through the change of writhing reflex Materials and Methods:Pain animal model was used acetic acid method. The changes of writhing reflex of the mice which were derived pain by injecting acetic acid into the abdomen, after stimulating Bee Venom aqua-acupuncture on Chungwan(CV12 and non acupuncture point on the backside were measured. Results:1. It showed that the writhing reflex were appeared on the groups which injected acetic acid only, and saline-acetic acid group(sample I, but not on the group bee venom-saline group(sample II. 2. The change of writhing reflex by Chungwan(CV12 Bee Venom aqua-acupuncture showed significant decrease in the order of Chungwan(CV12 Bee Venom aqua-acupuncture group III(2.5×10-3g/kg, II(2.5×10-4g/kg, and I(2.5×10-5g/kg, compared with control group. There were significant decrease of number of writhing reflex in 5～10, 10～15 and 15～20 minutes intervals of Chung wan(CV12 Bee Venom aqua-acupuncture group I, and in 0～5, 5～10, 10～15 and 15～20 minutes intervals of II and III, compared with control group. 3. The change of writhing reflex by non acupuncture point Bee Venom aqua-acupuncture showed significant decrease in the 0～5 and 5～10 minutes intervals and the total number of writhing reflex in 2.5×10-4g/kg group, compared with control group 4. The effects of writhing reflex of Chungwan(CV12 Bee Venom aqua-acupuncture group showed significant decrease, compared with non acupuncture point Bee Venom aqua-acupuncture group. Conclusion:This study shows that the Bee Venom aqua-acupuncture on Chungwan(CV12 decreases the numbers of writhing reflex. As the

Creating safety by strengthening clinicians' capacity for reflexivity

Science.gov (United States)

2011-01-01

This commentary explores the nature of creating safety in the here-and-now. Creating safety encompasses two dimensions: revisiting specific behaviours by focusing on substandard performance (reflection), and a more broad-ranging attention to everyday behaviours that are taken as given (reflexivity). The piece pays particular attention to this second dimension of creating safety. Two techniques that promote reflexivity are discussed: video-filming real-time, everyday clinical practice and inviting clinicians' feedback about their own footage, and reflecting on the knowledge and questions that patients and families have about their care, and about unexpected outcomes and clinical incidents. The piece concludes that feedback about everyday practice using these methods is critical to enhancing the safety of everyday activity. PMID:21450780

A method of reflexive balancing in a pragmatic, interdisciplinary and reflexive bioethics.

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Ives, Jonathan

2014-07-01

In recent years there has been a wealth of literature arguing the need for empirical and interdisciplinary approaches to bioethics, based on the premise that an empirically informed ethical analysis is more grounded, contextually sensitive and therefore more relevant to clinical practice than an 'abstract' philosophical analysis. Bioethics has (arguably) always been an interdisciplinary field, and the rise of 'empirical' (bio)ethics need not be seen as an attempt to give a new name to the longstanding practice of interdisciplinary collaboration, but can perhaps best be understood as a substantive attempt to engage with the nature of that interdisciplinarity and to articulate the relationship between the many different disciplines (some of them empirical) that contribute to the field. It can also be described as an endeavour to explain how different disciplinary approaches can be integrated to effectively answer normative questions in bioethics, and fundamental to that endeavour is the need to think about how a robust methodology can be articulated that successfully marries apparently divergent epistemological and metaethical perspectives with method. This paper proposes 'Reflexive Bioethics' (RB) as a methodology for interdisciplinary and empirical bioethics, which utilizes a method of 'Reflexive Balancing' (RBL). RBL has been developed in response to criticisms of various forms of reflective equilibrium, and is built upon a pragmatic characterization of Bioethics and a 'quasi-moral foundationalism', which allows RBL to avoid some of the difficulties associated with RE and yet retain the flexible egalitarianism that makes it intuitively appealing to many. © 2013 John Wiley & Sons Ltd.

Genetic Influence on Slope Variability in a Childhood Reflexive Attention Task.

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Rebecca A Lundwall

Full Text Available Individuals are not perfectly consistent, and interindividual variability is a common feature in all varieties of human behavior. Some individuals respond more variably than others, however, and this difference may be important to understanding how the brain works. In this paper, we explore genetic contributions to response time (RT slope variability on a reflexive attention task. We are interested in such variability because we believe it is an important part of the overall picture of attention that, if understood, has the potential to improve intervention for those with attentional deficits. Genetic association studies are valuable in discovering biological pathways of variability and several studies have found such associations with a sustained attention task. Here, we expand our knowledge to include a reflexive attention task. We ask whether specific candidate genes are associated with interindividual variability on a childhood reflexive attention task in 9-16 year olds. The genetic makers considered are on 11 genes: APOE, BDNF, CHRNA4, COMT, DRD4, HTR4, IGF2, MAOA, SLC5A7, SLC6A3, and SNAP25. We find significant associations with variability with markers on nine and we discuss the results in terms of neurotransmitters associated with each gene and the characteristics of the associated measures from the reflexive attention task.

Oriented heat release in asphalt pavement induced by high-thermal-conductivity rods

International Nuclear Information System (INIS)

Du, Yinfei; Wang, Shengyue

2015-01-01

In this paper, a new principle of using aligned high-thermal-conductivity rods to enhance the oriented heat conduction in asphalt pavement was proposed. The results showed that the designed structure absorbed more heat during the day. The heat flow in the designed structure presented a non-uniform horizontal distribution. At the depth of 4 cm, the horizontal and vertical heat fluxes through steel rods were thirteen and ten times higher than those through asphalt mixture, respectively. The maximum temperature of the designed structure reduced by 3.6 °C–6.5 °C at the depth of 4 cm. The results of indoor irradiation test showed a trend consistent with those of numerical simulation. After 500 thousand times of standard axis load were applied, the rutting depth of the designed structure reduced by 43.4%. The principle proposed is expected to be used to induce an oriented heat release accumulated in asphalt pavement and reduce pavement temperature and rutting. - Highlights: • Steel rods were inserted in the middle and bottom layers to build thermal channels. • Steel rods absorbed heat from asphalt mixture and rapidly released them to subgrade. • The heat flux through asphalt mixture decreased and pavement temperature reduced.

Encouraging Reflexivity in Urban Geography Fieldwork: Study Abroad Experiences in Singapore and Malaysia

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Glass, Michael R.

2014-01-01

Fieldwork in urban geography courses can encourage reflexivity among students regarding the cities they encounter. This article outlines how student reflexivity was encouraged within a new international field research course in Singapore and Malaysia. Drawing on examples from students' field exercises written during an intensive and occasionally…

Reflexivity in the Interstices: A Tale of Reflexivity at Work in, during, and behind the Scenes

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Wickens, Corrine M.; Cohen, James A.; Walther, Carol S.

2017-01-01

This article is a story of how the authors came to make sense of the significance of those words in relation to gender, race/ethnicity, and citizenship in writing a manuscript about L[subscript 1]L[subscript 2] acquisition. It is a tale about how Reflexivity wove itself into the conversations, into the writing, into the in-between spaces, the…

Short-term plasticity in a monosynaptic reflex pathway to forearm muscles after continuous robot-assisted passive stepping

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Tsuyoshi Nakajima

2016-07-01

Full Text Available Both active and passive rhythmic limb movements reduce the amplitude of spinal cord Hoffmann (H- reflexes in muscles of moving and distant limbs. This could have clinical utility in remote modulation of the pathologically hyperactive reflexes found in spasticity after stroke or spinal cord injury. However, such clinical translation is currently hampered by a lack of critical information regarding the minimum or effective duration of passive movement needed for modulating spinal cord excitability. We therefore investigated the H-reflex modulation in the flexor carpi radialis (FCR muscle during and after various durations (5, 10, 15, and 30 min of passive stepping in 11 neurologically normal subjects. Passive stepping was performed by a robotic gait trainer system (Lokomat® while a single pulse of electrical stimulation to the median nerve elicited H-reflexes in the FCR. The amplitude of the FCR H-reflex was significantly suppressed during passive stepping. Although 30 minutes of passive stepping was sufficient to elicit a persistent H-reflex suppression that lasted up to 15 minutes, 5 minutes of passive stepping was not. The duration of H-reflex suppression correlated with that of the stepping. These findings suggest that the accumulation of stepping-related afferent feedback from the leg plays a role in generating short-term interlimb plasticity in the circuitry of the FCR H-reflex.

Differences in neurotransmitter systems of ventrolateral periaqueductal gray between the micturition reflex and nociceptive regulation : An in vivo microdialysis study

OpenAIRE

Kitta, Takeya; Mitsui, Takahiko; Kanno, Yukiko; Chiba, Hiroki; Moriya, Kimihiko; Yoshioka, Mitsuhiro; Shinohara, Nobuo

2016-01-01

Objectives: To elucidate the possible involvement of glutamate and serotonin (5-hydroxytryptamine) neurons in the ventrolateral midbrain periaqueductal gray during noxious stimulation. Methods: The study was carried out by evoking a noxious stimulation by acetic acid in an animal model of cystitis. Changes in glutamate and 5-hydroxytryptamine in the periaqueductal gray during the micturition reflex and acetic acid-induced cystitis were determined using in vivo microdialysis combined with cyst...

Iterative Algorithm for Solving a Class of Quaternion Matrix Equation over the Generalized (P,Q-Reflexive Matrices

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Ning Li

2013-01-01

Full Text Available The matrix equation ∑l=1uAlXBl+∑s=1vCsXTDs=F, which includes some frequently investigated matrix equations as its special cases, plays important roles in the system theory. In this paper, we propose an iterative algorithm for solving the quaternion matrix equation ∑l=1uAlXBl+∑s=1vCsXTDs=F over generalized (P,Q-reflexive matrices. The proposed iterative algorithm automatically determines the solvability of the quaternion matrix equation over generalized (P,Q-reflexive matrices. When the matrix equation is consistent over generalized (P,Q-reflexive matrices, the sequence {X(k} generated by the introduced algorithm converges to a generalized (P,Q-reflexive solution of the quaternion matrix equation. And the sequence {X(k} converges to the least Frobenius norm generalized (P,Q-reflexive solution of the quaternion matrix equation when an appropriate initial iterative matrix is chosen. Furthermore, the optimal approximate generalized (P,Q-reflexive solution for a given generalized (P,Q-reflexive matrix X0 can be derived. The numerical results indicate that the iterative algorithm is quite efficient.

Dynamics of a stabilized motor defense conditioned reflex at different levels of motivation in irradiated rats

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Shtemberg, A S

1982-05-01

Postradiation dynamics of strengthened motor-defense conditioned reflex in rats-males irradiated with the doses of 94.111 and 137 Gy was studied. Phase disturbances of conditioned-reflex activity increased with enhancing irradiation dose have been revealed. Rapid recovery of conditioned reflex after short primary aggravation was a characteristic peculiarity. At that, the dynamics of relation of main nervous processes in cortex was noted for significant instability increasing with radiation syndrome development. Enhancement of force of electro-defense support promoted more effective strengthening of temporary connections and conditioned high stability of trained-reflex reactions during serious functional disturbances resulted from sublethal dose irradiation.

Neurophysiology and Clinical Implications of the Laryngeal Adductor Reflex.

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Domer, Amanda S; Kuhn, Maggie A; Belafsky, Peter C

2013-09-01

The laryngeal adductor reflex (LAR) is an involuntary protective response to stimuli in the larynx. The superior laryngeal nerve (SLN) acts as the afferent limb and the recurrent laryngeal nerve (RLN) as the efferent limb of this reflex, which is modulated by the central nervous system. Perhaps the most clinically significant application of the LAR is its use in laryngopharyngeal (LP) sensory discrimination testing. Importantly, aberrations in the LAR may predict dysphagia or portend clinical phenotypes of chronic cough, vocal cord dysfunction or pediatric apneas. LP sensation is a potential target for interventions addressing the aforementioned conditions though currently remains an area of active investigation.

Modulation of cardiopulmonary depressor reflex in nucleus ambiguus by electroacupuncture: roles of opioids and γ-aminobutyric acid.

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Tjen-A-Looi, Stephanie C; Li, Peng; Li, Min; Longhurst, John C

2012-04-01

Stimulation of cardiopulmonary receptors with phenylbiguanide (PBG) elicits depressor cardiovascular reflex responses, including decreases in blood pressure and heart rate mediated in part by the brain stem parasympathetic cardiac neurons in the nucleus ambiguus (NAmb). The present study examined NAmb neurotransmitter mechanisms underlying the influence of electroacupuncture (EA) on the PBG-induced hypotension and bradycardia. We hypothesized that somatic stimulation during EA modulates PBG responses through opioid and γ-aminobutyric acid (GABA) modulation in the NAmb. Anesthetized and ventilated cats were studied during repeated stimulation with PBG or cardiac vagal afferents while low-frequency EA (2 Hz) was applied at P5-6 acupoints overlying the median nerve for 30 min and NAmb neuronal activity, heart rate, and blood pressure were recorded. Microinjection of kainic acid into the NAmb attenuated the PBG-induced bradycardia from -60 ± 11 to -36 ± 11 beats/min. Likewise, EA reduced the PBG-induced depressor and bradycardia reflex by 52 and 61%, respectively. Cardiac vagal afferent evoked preganglionic cellular activity in the NAmb was reduced by EA for about 60 min. Blockade of opioid or GABA(A) receptors using naloxone and gabazine reversed the EA-related modulation of the evoked cardiac vagal activity by 73 and 53%, respectively. Similarly, naloxone and gabazine reversed EA modulation of the negative chronotropic responses from -11 ± 5 to -23 ± 6 and -13 ± 4 to -24 ± 3 beats/min, respectively. Thus EA at P5-6 decreases PBG evoked hypotension and bradycardia as well as the NAmb PBG-sensitive preganglionic cardiac vagal outflow through opioid and GABA neurotransmitter systems.

Human H-reflexes are smaller in difficult beam walking than in normal treadmill walking.

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Llewellyn, M; Yang, J F; Prochazka, A

1990-01-01

Hoffman (H) reflexes were elicited from the soleus (SOL) muscle while subjects walked on a treadmill and on a narrow beam (3.5 cm wide, raised 34 cm from the floor). The speed of walking on the treadmill was selected for each subject to match the background activation level of their SOL muscle during beam walking. The normal reciprocal activation pattern of the tibialis anterior and SOL muscles in treadmill walking was replaced by a pattern dominated by co-contraction on the beam. In addition, the step cycle duration was more variable and the time spent in the swing phase was reduced on the beam. The H-reflexes were highly modulated in both tasks, the amplitude being high in the stance phase and low in the swing phase. The H-reflex amplitude was on average 40% lower during beam walking than treadmill walking. The relationship between the H-reflex amplitude and the SOL EMG level was quantified by a regression line relating the two variables. The slope of this line was on average 41% lower in beam walking than treadmill walking. The lower H-reflex gain observed in this study and the high level of fusimotor drive observed in cats performing similar tasks suggest that the two mechanisms which control the excitability of this reflex pathway (i.e. fusimotor action and control of transmission at the muscle spindle to moto-neuron synapse) may be controlled independently.

Transcranial Direct Current Stimulation (tDCS) Enhances the Excitability of Trigemino-Facial Reflex Circuits.

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Cabib, Christopher; Cipullo, Federica; Morales, Merche; Valls-Solé, Josep

2016-01-01

Transcranial direct current stimulation (tDCS) causes a tiny burning sensation through activation of local cutaneous trigeminal afferents. Trigeminal sensory inputs from tDCS may generate excitability changes in the trigemino-facial reflex circuits. Sixteen healthy volunteers were submitted to 20 minutes tDCS sessions with two types of electrode-montage conditions: 1. Real vs Sham 'bi-hemispheric' tDCS (cathode/anode: C4/C3), for blinded assessment of effects, and 2. 'uni-hemispheric' tDCS (cathode/anode: Fp3/C3), for assessment of laterality of the effects. Supraorbital nerve stimuli were used to obtain blink reflexes before, during (10 minutes from onset) and after (30 minutes from onset) the tDCS session. Outcome measures were R2 habituation (R2H) to repeated stimuli, the blink reflex excitability recovery (BRER) to paired stimuli and the blink reflex inhibition by a prepulse (BRIP). Real but not sham bi-hemispheric tDCS caused a significant decrease of R2H and leftward shift of BRER curve (p tDCS on BRER and BRIP were larger on ipsilateral than on contralateral blink reflexes (p tDCS enhances the excitability of trigemino-facial reflex circuits. The finding of larger ipsilateral than contralateral effects suggests that sensitization through cutaneous trigeminal afferents adds on other possible mechanisms such as activation of cortico-nuclear or cortico-reticular connections. Copyright © 2016 Elsevier Inc. All rights reserved.

Response of pontomedullary reticulospinal neurons to vestibular stimuli in vertical planes. Role in vertical vestibulospinal reflexes of the decerebrate cat

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Bolton, P. S.; Goto, T.; Schor, R. H.; Wilson, V. J.; Yamagata, Y.; Yates, B. J.

1992-01-01

1. To investigate the neural substrate of vestibulospinal reflexes in decerebrate cats, we studied the responses of pontomedullary reticulospinal neurons to natural stimulation of the labyrinth in vertical planes. Our principal aim was to determine whether reticulospinal neurons that terminate in, or are likely to give off collaterals to, the upper cervical segments had properties similar to those of the vestibulocollic reflex (VCR). 2. Antidromic stimulation was used to determine whether the neurons projected to the neck, lower cervical, thoracic, or lumbar levels. Dynamics of the responses of spontaneously firing neurons were studied with sinusoidal stimuli delivered at 0.05-1 Hz and aligned to the plane of body rotation, that produced maximal modulation of the neuron (response vector orientation). Each neuron was assigned a vestibular input classification of otolith, vertical canal, otolith + canal, or spatial-temporal convergence (STC). 3. We found, in agreement with previous studies, that the largest fraction of pontomedullary reticulospinal neurons projected to the lumbar cord, and that only a small number ended in the neck segments. Neurons projecting to all levels of the spinal cord had similar responses to labyrinth stimulation. 4. Reticulospinal neurons that received only vertical canal inputs were rare (1 of 67 units). Most reticulospinal neurons (48%) received predominant otolith inputs, 18% received otolith + canal input, and only 9% had STC behavior. These data are in sharp contrast to the results of our previous studies of vestibulospinal neurons. A considerable portion of vestibulospinal neurons receives vertical canal input (38%), fewer receive predominantly otolith input (22%), whereas the proportion that have otolith + canal input or STC behavior is similar to our present reticulospinal data. 5. The response vector orientations of our reticulospinal neurons, particularly those with canal inputs (canal, otolith + canal, STC) were predominantly in

Central sensitization in spinal cord injured humans assessed by reflex receptive fields

DEFF Research Database (Denmark)

Biurrun Manresa, José Alberto; Finnerup, Nanna Susanne Brix; Johannesen, Inger Lauge

2014-01-01

OBJECTIVE: To investigate the effects of central sensitization, elicited by intramuscular injection of capsaicin, by comparing the reflex receptive fields (RRF) of spinally-intact volunteers and spinal cord injured volunteers that present presensitized spinal nociceptive mechanisms. METHODS...... after an intramuscular injection of capsaicin in the foot sole in order to induce central sensitization. RESULTS: Both groups presented RRF expansion and lowered NWR thresholds immediately after capsaicin injection, reflected by the enlargement of RRF sensitivity areas and RRF probability areas....... Moreover, the topography of the RRF sensitivity and probability areas were significantly different in SCI volunteers compared to NI volunteers in terms of size and shape. CONCLUSIONS: SCI volunteers can develop central sensitization, despite adaptive/maladaptive changes in synaptic plasticity and lack...

Sensor-Motor Maps for Describing Linear Reflex Composition in Hopping

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Christian Schumacher

2017-11-01

Full Text Available In human and animal motor control several sensory organs contribute to a network of sensory pathways modulating the motion depending on the task and the phase of execution to generate daily motor tasks such as locomotion. To better understand the individual and joint contribution of reflex pathways in locomotor tasks, we developed a neuromuscular model that describes hopping movements. In this model, we consider the influence of proprioceptive length (LFB, velocity (VFB and force feedback (FFB pathways of a leg extensor muscle on hopping stability, performance and efficiency (metabolic effort. Therefore, we explore the space describing the blending of the monosynaptic reflex pathway gains. We call this reflex parameter space a sensor-motor map. The sensor-motor maps are used to visualize the functional contribution of sensory pathways in multisensory integration. We further evaluate the robustness of these sensor-motor maps to changes in tendon elasticity, body mass, segment length and ground compliance. The model predicted that different reflex pathway compositions selectively optimize specific hopping characteristics (e.g., performance and efficiency. Both FFB and LFB were pathways that enable hopping. FFB resulted in the largest hopping heights, LFB enhanced hopping efficiency and VFB had the ability to disable hopping. For the tested case, the topology of the sensor-motor maps as well as the location of functionally optimal compositions were invariant to changes in system designs (tendon elasticity, body mass, segment length or environmental parameters (ground compliance. Our results indicate that different feedback pathway compositions may serve different functional roles. The topology of the sensor-motor map was predicted to be robust against changes in the mechanical system design indicating that the reflex system can use different morphological designs, which does not apply for most robotic systems (for which the control often follows a

Sensor-Motor Maps for Describing Linear Reflex Composition in Hopping.

Science.gov (United States)

Schumacher, Christian; Seyfarth, André

2017-01-01

In human and animal motor control several sensory organs contribute to a network of sensory pathways modulating the motion depending on the task and the phase of execution to generate daily motor tasks such as locomotion. To better understand the individual and joint contribution of reflex pathways in locomotor tasks, we developed a neuromuscular model that describes hopping movements. In this model, we consider the influence of proprioceptive length (LFB), velocity (VFB) and force feedback (FFB) pathways of a leg extensor muscle on hopping stability, performance and efficiency (metabolic effort). Therefore, we explore the space describing the blending of the monosynaptic reflex pathway gains. We call this reflex parameter space a sensor-motor map . The sensor-motor maps are used to visualize the functional contribution of sensory pathways in multisensory integration. We further evaluate the robustness of these sensor-motor maps to changes in tendon elasticity, body mass, segment length and ground compliance. The model predicted that different reflex pathway compositions selectively optimize specific hopping characteristics (e.g., performance and efficiency). Both FFB and LFB were pathways that enable hopping. FFB resulted in the largest hopping heights, LFB enhanced hopping efficiency and VFB had the ability to disable hopping. For the tested case, the topology of the sensor-motor maps as well as the location of functionally optimal compositions were invariant to changes in system designs (tendon elasticity, body mass, segment length) or environmental parameters (ground compliance). Our results indicate that different feedback pathway compositions may serve different functional roles. The topology of the sensor-motor map was predicted to be robust against changes in the mechanical system design indicating that the reflex system can use different morphological designs, which does not apply for most robotic systems (for which the control often follows a specific

Research progress of the relationship between abnormal vestibular reflexes and adolescent idiopathic scoliosis

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Yi-Lin Yang

2017-01-01

Full Text Available Adolescent idiopathic scoliosis (AIS is an agnogenic structural scoliosis occurring in adolescence, and the main diagnostic criteria is coronal Cobb angle >10°in total spine X-ray. Studies have shown that AIS may be associated with abnormal postural reflexes, vestibular system is an important component of postural reflexes and its mechanism in the occurrence and development of scoliosis has received wide attention in recent years. In the study, the research progress on the role of abnormal vestibular reflexes in the pathogenesis of AIS was mainly introduced to help the clinicians better understand the pathogenesis of AIS and provide new ideas for AIS study.

Changes in myosin S1 orientation and force induced by a temperature increase.

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Griffiths, Peter J; Bagni, Maria A; Colombini, Barbara; Amenitsch, Heinz; Bernstorff, Sigrid; Ashley, Christopher C; Cecchi, Giovanni; Ameritsch, Heinz

2002-04-16

Force generation in myosin-based motile systems is thought to result from an angular displacement of the myosin subfragment 1 (S1) tail domain with respect to the actin filament axis. In muscle, raised temperature increases the force generated by S1, implying a greater change in tail domain angular displacement. We used time-resolved x-ray diffraction to investigate the structural corollary of this force increase by measuring M3 meridional reflection intensity during sinusoidal length oscillations. This technique allows definition of S1 orientation with respect to the myofilament axis. M3 intensity changes were approximately sinusoid at low temperatures but became increasingly distorted as temperature was elevated, with the formation of a double intensity peak at maximum shortening. This increased distortion could be accounted for by assuming a shift in orientation of the tail domain of actin-bound S1 toward the orientation at which M3 intensity is maximal, which is consistent with a tail domain rotation model of force generation in which the tail approaches a more perpendicular projection from the thin filament axis at higher temperatures. In power stroke simulations, the angle between S1 tail mean position during oscillations and the position at maximum intensity decreased by 4.7 degrees, corresponding to a mean tail displacement toward the perpendicular of 0.73 nm for a temperature-induced force increase of 0.28 P(0) from 4 to 22 degrees C. Our findings suggest that at least 62% of crossbridge compliance is associated with the tail domain.

CAROTID BODY CHEMO-REFLEX: A DRIVER OF AUTONOMIC ABNORMALITIES IN SLEEP APNEA

Science.gov (United States)

Prabhakar, Nanduri R.

2016-01-01

Carotid bodies are the principal peripheral chemoreceptors for detecting changes in arterial blood oxygen levels, and the resulting chemo-reflex is a potent regulator of the sympathetic tone, blood pressure, and breathing. Sleep apnea is a disease of the respiratory system affecting several million adult humans. Apneas occur during sleep often due to obstruction of the upper airway (obstructive sleep apnea, OSA) or due to defective respiratory rhythm generation by the central nervous system (central sleep apnea). Patients with sleep apnea exhibit several co-morbidities; most notable among them being the heightened sympathetic nerve activity, and hypertension. Emerging evidence suggests that intermittent hypoxia (IH) resulting from periodic apnea stimulates the carotid body and the ensuing chemo-reflex mediates the increased sympathetic tone and hypertension in sleep apnea patients. Rodent models of IH, simulating the O2 saturation profiles encountered during sleep apnea have provided important insights into the cellular and molecular mechanisms underlying the heightened carotid body chemo-reflex. This article describes how IH affects the carotid body function, and discusses the cellular, molecular and epigenetic mechanisms underlying the exaggerated chemo-reflex. PMID:27474260

The mechano-gated channel inhibitor GsMTx4 reduces the exercise pressor reflex in decerebrate rats.

Science.gov (United States)

Copp, Steven W; Kim, Joyce S; Ruiz-Velasco, Victor; Kaufman, Marc P

2016-02-01

Mechanical and metabolic stimuli from contracting muscles evoke reflex increases in blood pressure, heart rate and sympathetic nerve activity. Little is known, however, about the nature of the mechano-gated channels on the thin fibre muscle afferents that contribute to evoke this reflex, termed the exercise pressor reflex. We determined the effect of GsMTx4, an inhibitor of mechano-gated Piezo channels, on the exercise pressor reflex evoked by intermittent contraction of the triceps surae muscles in decerebrated, unanaesthetized rats. GsMTx4 reduced the pressor, cardioaccelerator and renal sympathetic nerve responses to intermittent contraction but did not reduce the pressor responses to femoral arterial injection of compounds that stimulate the metabolically-sensitive thin fibre muscle afferents. Expression levels of Piezo2 channels were greater than Piezo1 channels in rat dorsal root ganglia. Our findings suggest that mechanically-sensitive Piezo proteins contribute to the generation of the mechanical component of the exercise pressor reflex in rats. Mechanical and metabolic stimuli within contracting skeletal muscles evoke reflex autonomic and cardiovascular adjustments. In cats and rats, gadolinium has been used to investigate the role played by the mechanical component of this reflex, termed the exercise pressor reflex. Gadolinium, however, has poor selectivity for mechano-gated channels and exerts multiple off-target effects. We tested the hypothesis that GsMTX4, a more selective mechano-gated channel inhibitor than gadolinium and a particularly potent inhibitor of mechano-gated Piezo channels, reduced the exercise pressor reflex in decerebrate rats. Injection of 10 μg of GsMTx4 into the arterial supply of the hindlimb reduced the peak pressor (control: 24 ± 5, GsMTx4: 12 ± 5 mmHg, P acid. Moreover, injection of 10 μg of GsMTx4 into the arterial supply of the hindlimb reduced the peak pressor (control: 24 ± 2, GsMTx4: 14 ± 3 mmHg, P reflex in

[Early diagnosis and prognosis evaluation of Bell palsy with blink reflex ].

Science.gov (United States)

Xie, Dan-dan; Li, Xiao-song; Liu, Yuan-yuan

2014-11-01

To determine the value of blink reflex in early diagnosis and prognosis evaluation of Bell palsy. Blink reflex and facial nerve conduction were examined in 58 patients with Bell palsy within one week after symptom onset. The patients without response of R1 , R2 and R2 ' waves were classified as complete efferent retardarce (Group A, 30 cases), and those with response of R1 , R2 and R2 ' waves were classified as incomplete efferent anomalies (Group B, 28 cases). The clinical outcomes after three months of systemic therapy were evaluated using the House-Blackmann (H-B) scale. Efferent anomalies of blink reflex occurred in ail of the 58 patients. Abnormal results of facial nerve conduction appeared in 23 (39. 7%) patients. The three months therapy was effective in 93% patients in Group B and 70% patients in Group A (PBell palsy.

Review Essay: Grenzgänger Seeks Reflexive Methodology

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Wolff-Michael Roth

2002-09-01

Full Text Available Reflexive Methodology reviews major strands of current thought in epistemology, philosophy, social science, and interpretive methods. The book falls short in that it neither does a thorough job reviewing the literature nor does it provide method-related advice useful to students. Grenzgängerin constitutes a collection of essays on a broad range of topics, but which are only loosely connected if at all. Drawing on DERRIDA and the notion of a historical science of the historical subject, I attempt to practice method, something I missed in both texts. I make explicit the historical nature of my own writing and the historical nature of my subject. I make explicit intertextuality and in the process practice reflexivity in the particular way I am writing. URN: urn:nbn:de:0114-fqs020328

Faroese long-distance reflexives face off against Icelandic long-distance reflexives

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Tania E. Strahan

2009-01-01

Full Text Available Long-distance reflexives (LDRs in Faroese are often compared to those in Icelandic, and are even considered to have the same distribution (Thráinsson et al., 2004. In this paper I evaluate the extent to which this is true. The results from recent fieldwork show that there are clear differences between the LDR in the two closely related languages, in particular that Faroese speakers often reject LDR sentences that contain a non-third person, and that Faroese LDR is often completely acceptable out of a non-complement clause. In addition, initial findings suggest that there may be dialectal variation with respect to at least these two aspects of LDR in Faroese.

COMPARATIVE ANALYSIS OF PERSONALITY CORRELATES OF REFLEXIVITY IN THE CONTEXT OF PROFESSIONAL FORMATION OF THE TEACHER

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T. V. Mayasova

2017-01-01

Full Text Available This article examines the reflexive, the most important professional quality of a teacher's personality in the context of professional development. Reflexivity is a basic property of the individual, whereby the awareness and regulation of the subject of their activities. As a personal correlates of reflexivity studied mental stability, individual styles of decision making (vigilance and avoidance, spontaneity, emotional intelligence (empathy and the ability to manage emotions of other people. The paper conducts a comparative analysis of reflexivity and qualities correlated with her young teachers, working in the specialty from 1 to 5 years and students from different areas of training of pedagogical University. Obtained in the course of the empirical research results confirmed that the process of professional development of teachers is the development of these qualities. Were no significant differences in the indicators options system the reflexivity, alertness,spontaneity, empathy, which differ among teachers and students.

Capsaicin-sensitive muscle afferents modulate the monosynaptic reflex in response to muscle ischemia and fatigue in the rat.

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Della Torre, G; Brunetti, O; Pettorossi, V E

2002-01-01

The role of muscle ischemia and fatigue in modulating the monosynaptic reflex was investigated in decerebrate and spinalized rats. Field potentials and fast motoneuron single units in the lateral gastrocnemious (LG) motor pool were evoked by dorsal root stimulation. Muscle ischemia was induced by occluding the LG vascular supply and muscle fatigue by prolonged tetanic electrical stimulation of the LG motor nerve. Under muscle ischemia the monosynaptic reflex was facilitated since the size of the early and late waves of the field potential and the excitability of the motoneuron units increased. This effect was abolished after L3-L6 dorsal rhizotomy, but it was unaffected after L3-L6 ventral rhizotomy. By contrast, the monosynaptic reflex was inhibited by muscle fatiguing stimulation, and this effect did not fully depend on the integrity of the dorsal root. However, when ischemia was combined with repetitive tetanic muscle stimulation the inhibitory effect of fatigue was significantly enhanced. Both the ischemia and fatigue effects were abolished by capsaicin injected into the LG muscle at a dose that blocked a large number of group III and IV muscle afferents. We concluded that muscle ischemia and fatigue activate different groups of muscle afferents that are both sensitive to capsaicin, but enter the spinal cord through different roots. They are responsible for opposite effects, when given separately: facilitation during ischemia and inhibition during fatigue; however, in combination, ischemia enhances the responsiveness of the afferent fibres to fatigue.

Dilemmas and Deliberations in Reflexive Ethnographic Research

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Robinson, Janean Valerie

2014-01-01

This paper traces insights into the challenges and dilemmas experienced whilst researching students' interpretations and understandings of the Behaviour Management in Schools policy in Western Australia. Journal records, supported by student transcripts, are woven together in a reflexive ethnographic journey--from the beginning phase of searching…

sEMG during Whole-Body Vibration Contains Motion Artifacts and Reflex Activity

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Karin Lienhard

2015-01-01

Full Text Available The purpose of this study was to determine whether the excessive spikes observed in the surface electromyography (sEMG spectrum recorded during whole-body vibration (WBV exercises contain motion artifacts and/or reflex activity. The occurrence of motion artifacts was tested by electrical recordings of the patella. The involvement of reflex activity was investigated by analyzing the magnitude of the isolated spikes during changes in voluntary background muscle activity. Eighteen physically active volunteers performed static squats while the sEMG was measured of five lower limb muscles during vertical WBV using no load and an additional load of 33 kg. In order to record motion artifacts during WBV, a pair of electrodes was positioned on the patella with several layers of tape between skin and electrodes. Spectral analysis of the patella signal revealed recordings of motion artifacts as high peaks at the vibration frequency (fundamental and marginal peaks at the multiple harmonics were observed. For the sEMG recordings, the root mean square of the spikes increased with increasing additional loads (p < 0.05, and was significantly correlated to the sEMG signal without the spikes of the respective muscle (r range: 0.54 - 0.92, p < 0.05. This finding indicates that reflex activity might be contained in the isolated spikes, as identical behavior has been found for stretch reflex responses evoked during direct vibration. In conclusion, the spikes visible in the sEMG spectrum during WBV exercises contain motion artifacts and possibly reflex activity.

Reflexive Language and Ethnic Minority Activism in Hong Kong: A Trajectory-Based Analysis

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Pérez-Milans, Miguel; Soto, Carlos

2016-01-01

This article engages with Archer's call to further research on reflexivity and social change under conditions of late modernity (2007, 2010, 2012) from the perspective of existing work on reflexive discourse in the language disciplines (Silverstein 1976, Lucy 1993). Drawing from a linguistic ethnography of the networked trajectories of a group of…

Prevalence of Persistent Primary Reflexes and Motor Problems in Children with Reading Difficulties

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McPhillips, M.; Sheehy, N.

2004-01-01

It has been shown that some children with reading difficulties have underlying developmental delay and that this may be related to the persistence of primary reflexes. This study investigated the prevalence of persistent primary reflexes in the ordinary primary school population and how this related to other cognitive and social factors. Three…

Reflexive cartography a new perspective in mapping

CERN Document Server

Casti, Emanuela

2015-01-01

Reflexive Cartography addresses the adaptation of cartography, including its digital forms (GIS, WebGIS, PPGIS), to the changing needs of society, and outlines the experimental context aimed at mapping a topological space. Using rigorous scientific analysis based on statement consistency, relevance of the proposals, and model accessibility, it charts the transition from topographical maps created by state agencies to open mapping produced by citizens. Adopting semiotic theory to uncover the complex communicative mechanisms of maps and to investigate their ability to produce their own messages and new perspectives, Reflexive Cartography outlines a shift in our way of conceptualizing maps: from a plastic metaphor of reality, as they are generally considered, to solid tools that play the role of agents, assisting citizens as they think and plan their own living place and make sense of the current world. Applies a range of technologies to theoretical perspectives on mapping to innovatively map the world's geogr...

Retrieval Interference in Syntactic Processing: The Case of Reflexive Binding in English.

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Patil, Umesh; Vasishth, Shravan; Lewis, Richard L

2016-01-01

It has been proposed that in online sentence comprehension the dependency between a reflexive pronoun such as himself/herself and its antecedent is resolved using exclusively syntactic constraints. Under this strictly syntactic search account, Principle A of the binding theory-which requires that the antecedent c-command the reflexive within the same clause that the reflexive occurs in-constrains the parser's search for an antecedent. The parser thus ignores candidate antecedents that might match agreement features of the reflexive (e.g., gender) but are ineligible as potential antecedents because they are in structurally illicit positions. An alternative possibility accords no special status to structural constraints: in addition to using Principle A, the parser also uses non-structural cues such as gender to access the antecedent. According to cue-based retrieval theories of memory (e.g., Lewis and Vasishth, 2005), the use of non-structural cues should result in increased retrieval times and occasional errors when candidates partially match the cues, even if the candidates are in structurally illicit positions. In this paper, we first show how the retrieval processes that underlie the reflexive binding are naturally realized in the Lewis and Vasishth (2005) model. We present the predictions of the model under the assumption that both structural and non-structural cues are used during retrieval, and provide a critical analysis of previous empirical studies that failed to find evidence for the use of non-structural cues, suggesting that these failures may be Type II errors. We use this analysis and the results of further modeling to motivate a new empirical design that we use in an eye tracking study. The results of this study confirm the key predictions of the model concerning the use of non-structural cues, and are inconsistent with the strictly syntactic search account. These results present a challenge for theories advocating the infallibility of the human

Clinical and electrophysiological findings in patients with phenylketonuria and epilepsy: Reflex features.

Science.gov (United States)

Yildiz Celik, Senay; Bebek, Nerses; Gurses, Candan; Baykan, Betul; Gokyigit, Aysen

2018-03-23

Phenylketonuria (PKU) is the most common form of amino acid metabolism disorders with autosomal recessive inheritance. The brain damage can be prevented by early diagnosis and a phenylalanine-restricted diet. Untreated or late-treated patients may show mental retardation and other cognitive dysfunctions, as well as motor disability and/or epilepsy. Three patients with PKU and epilepsy were recognized to have reflex epileptic features, and there were ten consecutive adult patients with PKU and epilepsy who were evaluated retrospectively. Medical history, ages at diagnosis and therapy onset, age at seizure onset, seizure types and reflex features, neurological findings, cranial imaging, electroencephalography (EEG) findings, and final clinical condition were evaluated. Reflex epilepsy features were examined in detail. The cases (6 females, 4 males) were diagnosed at ages between 3.5months and 12years. All patients had various degrees of mental-motor retardation and focal or generalized seizures with age at seizure onset varied between neonatal period and 15years. Three patients had febrile seizure, 3 patients had myoclonia, and 3 patients had status epilepticus. All patients had abnormal EEG findings except one. There was a slowing of background activity, and generalized discharges were observed in 7 patients; 3 of them had asymmetrical discharges. One patient had right hippocampal sclerosis (HS), and another patient had hypointensities in the basal ganglia and corpus callosum. Reflex features were clinically observed in 3 of the patients; however, EEG results did not show any related findings. One patient had reflex seizures triggered by photic stimuli, hot water, and startling; one by photic stimuli; and the other one by startling. Reports on the clinical and electrophysiological features of adult patients with PKU were scant. We emphasized that reflex clinical features may be observed in this metabolic disease, and focal epileptiform abnormalities and asymmetry

Cholesteric Liquid Crystal Based Reflex Color Reflective Displays

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Khan, Asad

2012-02-01

Bistable color cholesteric liquid crystal displays are unique LCDs that exhibit high reflectivity, good contrast, extremely low power operation, and are amenable to versatile roll-to-roll manufacturing. The display technology, now branded as Reflex has been in commercialized products since 1996. It has been the subject of extensive research and development globally by a variety of parties in both academic and industrial settings. Today, the display technology is in volume production for applications such as dedicated eWriters (Boogie Board), full color electronic skins (eSkin), and displays for smart cards. The flexibility comes from polymerization induced phase separation using unique materials unparalleled in any other display technology. The blend of monomers, polymers, cross linkers, and other components along with nematic liquid crystals and chiral dopants is created and processed in such ways so as to enable highly efficient manufactrable displays using ultra thin plastic substrates -- often as thin as 50μm. Other significant aspects include full color by stacking or spatial separation, night vision capability, ultra high resolution, as well as active matrix capabilities. Of particular note is the stacking approach of Reflex based displays to show full color. This approach for reflective color displays is unique to this technology. Owing to high transparency in wavelength bands outside the selective reflection band, three primarily color layers can be stacked on top of each other and reflect without interfering with other layers. This highly surprising architecture enables the highest reflectivity of any other reflective electronic color display technology. The optics, architecture, electro-topics, and process techniques will be discussed. This presentation will focus on the physics of the core technology and color, it's evolution from rigid glass based displays to flexible displays, development of products from the paradigm shifting concepts to consumer

Integrating Reflexivity in Livelihoods Research

DEFF Research Database (Denmark)

Prowse, Martin

2010-01-01

Much poverty and development research is not explicit about its methodology or philosophical foundations. Based on the extended case method of Burawoy and the epistemological standpoint of critical realism, this paper discusses a methodological approach for reflexive inductive livelihoods research...... that overcomes the unproductive social science dualism of positivism and social constructivism. The approach is linked to a conceptual framework and a menu of research methods that can be sequenced and iterated in light of research questions....

Spinal mechanism of micturition reflex inhibition by naftopidil in rats.

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Sugaya, Kimio; Nishijima, Saori; Kadekawa, Katsumi; Ashitomi, Katsuhiro; Ueda, Tomoyuki; Yamamoto, Hideyuki

2014-10-29

We investigated the spinal mechanism through which naftopidil inhibits the micturition reflex by comparing the effects of noradrenaline and naftopidil in rats. The following were investigated: the influence of oral naftopidil on plasma monoamine and amino acid levels, the distribution of oral 14C-naftopidil, the effects of intravenous (IV) or intrathecal (IT) injection of noradrenaline or naftopidil on isovolumetric bladder contractions, amino acid levels in the lumbosacral spinal cord after IT noradrenaline or naftopidil, and the effects of IT naftopidil and strychnine and/or bicuculline on isovolumetric bladder contractions. Oral naftopidil decreased the plasma adrenaline level, while it increased the serotonin and glycine levels. After oral administration, 14C-naftopidil was detected in the spinal cord and cerebrum, as well as in plasma and the prostate gland. When the bladder volume was below the threshold for isovolumetric reflex contractions, IV (0.1mg) or IT (0.1μg) noradrenaline evoked bladder contractions, but IV (1mg) or IT (0.01-1μg) naftopidil did not. When the bladder volume was above the threshold for isovolumetric reflex contractions, IV or IT noradrenaline transiently abolished bladder contractions. IT noradrenaline decreased the levels of glycine and gamma-aminobutyric acid (GABA) in the lumbosacral cord, while IT naftopidil increased the GABA level. IT strychnine and/or bicuculline blocked the inhibitory effect of IT naftopidil on bladder contractions. Naftopidil inhibits the micturition reflex by blocking α1 receptors, as well as by the activation of serotonergic, glycinergic, and GABAergic neurons in the central nervous system. Copyright © 2014 Elsevier Inc. All rights reserved.

Soleus H-reflex tests in causalgia-dystonia compared with dystonia and mimicked dystonic posture

NARCIS (Netherlands)

Koelman, J. H.; Hilgevoord, A. A.; Bour, L. J.; Speelman, J. D.; Ongerboer de Visser, B. W.

1999-01-01

Dystonia in the causalgia-dystonia syndrome is characterized by a fixed dystonic posture. To identify involvement of central pathophysiologic mechanisms, we analyzed soleus H-reflex tests in five patients with causalgia-dystonia. Soleus H-reflex test results in these patients differed from those in

Radiographic assessment of laryngeal reflexes in ketamine-anesthetized cats

International Nuclear Information System (INIS)

Robinson, E.P.; Johnston, G.R.

1986-01-01

The competence of the laryngeal closure reflexes of cats anesthetized with ketamine was assessed. Radiographic evaluations of the respiratory and digestive tracts were made after colloidal barium suspension was instilled into the pharynges of conscious and ketamine-anesthetized cats. There was a significant ketamine dose-related response of spread of contrast medium into the supraglottic laryngeal area and into the stomach 2 minutes after contrast medium was instilled into the pharynx (P less than 0.05). Cats did not aspirate contrast medium into the lower respiratory tract. Three ketamine-anesthetized cats aspirated contrast medium into the subglottic area of the larynx, and 2 of these cats also aspirated the material into the cranial part of the trachea. This material was coughed up and swallowed within 5 minutes. Transit time of contrast medium into the stomach seemed to be increased in 11 of the 15 cats given the larger dosages of ketamine (24, 36, 48 mg/kg of body weight), compared with that in conscious cats and those given ketamine at 12 mg/kg. Competent laryngeal protective reflexes in cats can be maintained with ketamine anesthesia. Contrast radiography could be used as a diagnostic aid in ketamine-anesthetized cats suspected of laryngeal reflex abnormalities

Influence of stimulus intensity on the soleus H-reflex amplitude and modulation during locomotion

DEFF Research Database (Denmark)

Simonsen, Erik B; Alkjær, Tine; Raffalt, Peter C

2013-01-01

-reflex methodology itself. Accordingly, the purpose of the present study was to study the effect on the soleus H-reflex during walking and running using stimulus intensities normally considered too high (up to 45% Mmax). Using M-waves of 25-45% Mmax as opposed to 5-25% Mmax showed a significant suppression...... of the peak H-reflex during the stance phase of walking, while no changes were observed during running. No differences were observed regarding modulation pattern. So a possible use of too high stimulus intensity cannot explain the differences mentioned. The surprising result in running may be explained...

Increased gamma-aminobutyric acid levels in mouse brain induce loss of righting reflex, but not immobility, in response to noxious stimulation.

Science.gov (United States)

Katayama, Sohtaro; Irifune, Masahiro; Kikuchi, Nobuhito; Takarada, Tohru; Shimizu, Yoshitaka; Endo, Chie; Takata, Takashi; Dohi, Toshihiro; Sato, Tomoaki; Kawahara, Michio

2007-06-01

The general anesthetic state comprises behavioral and perceptual components, including amnesia, unconsciousness, and immobility. gamma-Aminobutyric acidergic (GABAergic) inhibitory neurotransmission is an important target for anesthetic action at the in vitro cellular level. In vivo, however, the functional relevance of enhancing GABAergic neurotransmission in mediating essential components of the general anesthetic state is unknown. Gabaculine is a GABA-transaminase inhibitor that inhibits degradation of released GABA, and consequently increases endogenous GABA in the central nervous system. Here, we examined, behaviorally, the ability of increased GABA levels to produce components of the general anesthetic state. All drugs were administered systemically in adult male ddY mice. To assess the general anesthetic components, two end-points were used. One was loss of righting reflex (LORR; as a measure of unconsciousness); the other was loss of movement in response to tail-clamp stimulation (as a measure of immobility). Gabaculine induced LORR in a dose-dependent fashion with a 50% effective dose of 100 (75-134; 95% confidence limits) mg/kg. The behavioral and microdialysis studies revealed that the endogenous GABA-induced LORR occurred in a brain concentration-dependent manner. However, even larger doses of gabaculine (285-400 mg/kg) produced no loss of tail-clamp response. In contrast, all the tested volatile anesthetics concentration-dependently abolished both righting and tail-clamp response, supporting the evidence that volatile anesthetics act on a variety of molecular targets. These findings indicate that LORR is associated with enhanced GABAergic neurotransmission, but that immobility in response to noxious stimulation is not, suggesting that LORR and immobility are mediated through different neuronal pathways and/or regions in the central nervous system.

Enhancement of the intrinsic defecation reflex by mosapride, a 5-HT4 agonist, in chronically lumbosacral denervated guinea pigs.

Science.gov (United States)

Kojima, Yu; Fujii, Hisao; Katsui, Renta; Nakajima, Yoshiyuki; Takaki, Miyako

2006-10-01

The defecation reflex is composed of rectal distension-evoked rectal (R-R) reflex contractions and synchronous internal anal sphincter (R-IAS) reflex relaxations in guinea pigs. These R-R and R-IAS reflexes are controlled via extrinsic sacral excitatory nerve pathway (pelvic nerves), lumbar inhibitory nerve pathways (colonic nerves) and by intrinsic cholinergic excitatory and nitrergic inhibitory nerve pathways. The effect of mosapride (a prokinetic benzamide) on the intrinsic reflexes, mediated via enteric 5-HT(4) receptors, was evaluated by measuring the mechanical activity of the rectum and IAS in anesthetized guinea pigs using an intrinsic R-R and R-IAS reflex model resulting from chronic (two to nine days) lumbosacral denervation (PITH). In this model, the myenteric plexus remains undamaged and the distribution of myenteric and intramuscular interstitial cells of Cajal is unchanged. Although R-R and R-IAS reflex patterns markedly changed, the reflex indices (reflex pressure or force curve-time integral) of both the R-R contractions and the synchronous R-IAS relaxations were unchanged. The frequency of the spontaneous R and IAS motility was also unchanged. Mosapride (0.1-1.0 mg/kg) dose-dependently increased both intrinsic R-R (maximum: 1.82) and R-IAS reflex indices (maximum: 2.76) from that of the control (1.0) 6-9 days following chronic PITH. The dose-response curve was similar to that in the intact guinea pig, and had shifted to the left from that in the guinea pig after acute PITH. A specific 5-HT(4) receptor antagonist, GR 113808 (1.0 mg/kg), decreased both reflex indices by approximately 50% and antagonized the effect of mosapride 1.0 mg/kg. This was quite different from the result in the intact guinea pig where GR 113808 (1.0 mg/kg) did not affect either of the reflex indices. The present results indicate that mosapride enhanced the intrinsic R-R and R-IAS reflexes and functionally compensated for the deprivation of extrinsic innervation. The actions of

Práticas e reflexões de professoras numa pesquisa longitudinal

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Edda Curi

Full Text Available Analisa práticas e reflexões de professoras que participam de um grupo colaborativo no âmbito do Projeto Observatório da Educação, financiado pela Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes. Destaca a constituição do grupo, as ações desenvolvidas, as reflexões das professoras e as considerações que permitem avançar nos processos de ensino de Matemática e formação de professores. Examina cadernos de registros das professoras, atas de memória do grupo e depoimentos e apresenta a análise desse conteúdo, pela perspectiva de Bardin. Conclui ter havido avanços significativos nas práticas, pois o trabalho em grupo favoreceu o processo reflexivo das professoras sobre sua prática e seu desenvolvimento profissional, embora ainda existam fragilidades em algumas reflexões.

Dissociative identity disorder and prepulse inhibition of the acoustic startle reflex

Science.gov (United States)

Dale, Karl Yngvar; Flaten, Magne Arve; Elden, Åke; Holte, Arne

2008-01-01

A group of persons with dissociative identity disorder (DID) was compared with a group of persons with other dissociative disorders, and a group of nondiagnosed controls with regard to prepulse inhibition (PPI) of the acoustic startle reflex. The findings suggest maladaptive attentional processes at a controlled level, but not at a preattentive automatic level, in persons with DID. The prepulse occupied more controlled attentional resources in the DID group compared with the other two groups. Preattentive automatic processing, on the other hand, was normal in the DID group. Moreover, startle reflexes did not habituate in the DID group. In conclusion, increased PPI and delayed habituation is consistent with increased vigilance in individuals with DID. The present findings of reduced habituation of startle reflexes and increased PPI in persons with DID suggest the operation of a voluntary process that directs attention away from unpleasant or threatening stimuli. Aberrant voluntary attentional processes may thus be a defining characteristic in DID. PMID:18830396

Formation of cognitive structures in conditioned-reflex behavior in monkeys: Relationship with type of visual information.

Science.gov (United States)

Dudkin, K N; Chueva, I V

2009-02-01

The characteristics of learning processes and long-term memory (LTM) were studied in rhesus macaques discriminating visual stimuli (geometrical figures of different shapes, sizes, and orientations, and with different spatial relationships between image components). Trained monkeys were tested for the ability to perform invariant recognition after stimulus transformation, i.e., changes in size, shape, number of objects, and spatial relationships. Analysis of behavioral characteristics (correct solutions, refusals to decide, motor response times) revealed differences associated with the type of visual information. When monkeys discriminated between black and white geometrical figures of different shapes and orientations, as well as black-and-white figures with different shapes or orientations, the learning time was short and transformation of the stimuli had no effect on correct solutions: there was complete transfer of learning. When monkeys discriminated figures of different sizes or complex images with different spatial relationships, the learning time was significantly greater. Changes in the size and shape of figures led to significant reductions in correct solutions and significant increases in refusals to solve the task and in motor reaction times. Invariance of discrimination in this case appeared after additional training. The results obtained here showed that in conditioned reflex learning, the sensory processing of stimuli has the result that discriminatory features are formed in LTM, i.e., cognitive structures (functional neurophysiological mechanisms), these supporting the classification of visual images. The temporal conditioned link of the executive reaction is established with these. Their formation is determined by the type of sensory information and the existence in LTM of separate subsystems for spatial and non-spatial information.

Soleus H reflex extinction in controls and spastic patients: ordered occlusion or diffuse inhibition?

NARCIS (Netherlands)

Hilgevoord, A. A.; Bour, L. J.; Koelman, J. H.; Ongerboer de Visser, B. W.

1995-01-01

Extinction of the soleus H reflex at higher stimulus intensities is commonly attributed to retrograde conduction of action potentials in motor axons. This study was designed to gain further insight into the mechanisms underlying the extinction. The decrease of the H reflex was quantified in a group

Cortical and spinal assessment - a comparative study using encephalography and the nociceptive withdrawal reflex

DEFF Research Database (Denmark)

Fischer, I W; Gram, M; Hansen, T M

2017-01-01

solution in randomized order. The electroencephalogram (EEG) was recorded during rest and during immersion of the hand into ice-water. Electrical stimulation of the sole of the foot was used to elicit the nociceptive withdrawal reflex and the reflex amplitude was recorded. RESULTS: Data from thirty...

Evolutionary problems in non-reflexive spaces

Czech Academy of Sciences Publication Activity Database

Kružík, Martin; Zimmer, J.

2010-01-01

Roč. 16, č. 1 (2010), s. 1-22 ISSN 1262-3377 R&D Projects: GA AV ČR IAA1075402 Institutional research plan: CEZ:AV0Z10750506 Keywords : concentrations * energetic solution * energies with linear growth * oscillations * relaxation Subject RIV: BA - General Mathematics Impact factor: 1.084, year: 2009 http://library.utia.cas.cz/separaty/2008/MTR/kruzik-evolutionary problems in non-reflexive spaces.pdf

The joint discourse 'reflexive sustainable development'. From weak towards strong sustainable development

International Nuclear Information System (INIS)

Nilsen, Heidi Rapp

2010-01-01

The purpose of this paper is to contribute towards moving the predominant situation of weak sustainable development (WSD) in the direction of strong sustainable development (SSD). More people - academics, politicians, bureaucrats and laymen alike - need to recognize SSD as an alternative to WSD. A joint discourse of WSD and SSD is suggested, called reflexive sustainable development. Here, advocates of WSD and SSD must argue for each specific case why their solution is better. This will expose, amongst other things, the ethical foundations which form part of resulting policy advice. Reflexive sustainable development is to be framed in discourse ethics, thereby remedying the power imbalance and allowing for substantial discussion. Reflexive sustainable development builds on a common theoretical base but will not lead to consensus in all matters. A family metaphor is introduced to inspire a discourse of both consensus and compromise. (author)

Effects of gamma-aminobutyric acid on the Hering-Breuer inspiration-inhibiting reflex.

Science.gov (United States)

Aleksandrova, N P; Aleksandrov, V G; Ivanova, T G

2010-02-01

Acute experiments on rats were performed to study the effects of intraventricular microinjections of gamma-aminobutyric acid (GABA) on the volume-time parameters of external respiration and the inspiration-inhibiting Hering-Breuer reflex. The state of this reflex before and after GABA administration was assessed in terms of the extent of changes in the duration and amplitude of inspiratory oscillations in intrathoracic pressure in response to end-expiratory occlusion of the trachea. Administration of 20 microM GABA into the lateral ventricles of the brain decreased the minute ventilation (due to reductions in the respiratory frequency and respiratory volume), weakened respiratory muscle contractions, and decreased the peak airflow rate on inspiration and expiration. The response to end-expiratory occlusion decreased significantly after administration of GABA, demonstrating the involvement of GABAergic mechanisms in mediating the inspiration-inhibiting Hering-Breuer reflex.

From Postcolonial Criticism to Critics on Postcolonial Poetics – Edward Said's Orientalism from an Iconographic Perspective

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Tobias Akira Schickhaus

2017-05-01

Full Text Available Inside and outside the academy, Edward Said's work is both preeminent and controversial. Combining literary theory, the history of ideas, political analysis and the sociology of intellectuals, his groundbreaking book Orientalism has radically transformed the field of Oriental studies, arguably laying the foundation for postcolonial studies. Criticizing the condition of the Palestinian people, Said also has constantly provided a critique of US government policy in the Middle East and has thus proposed a model of intellectual skepticism which deals with political issues. This combination of political and academic interventions is one reason "for Said’s special position in contemporary Western intellectual life" (Kennedy 3. If we look at Said's classic monography as a painting of geographical knowledgelandscapes, an iconographical investigation into the traditions of knowledge and ideological styles becomes possible. This paper will begin by presenting Orientalism's arguments and will then summarize the main critiques aimed at Said. It continues to describe the analytic discourse in Orientalism based on the method of iconographic interpretation as described in Panofsky's collection of essays Meaning in the Visual Arts. This interdisciplinary approach intends to demonstrate the argumentative circularity and self-reflexivity inherent in Said's criticism: by drawing exclusively on Western histories of ideas, the concept Orientalism itself can become the object of postcolonial criticism.

Jaw-opening reflex and corticobulbar motor excitability changes during quiet sleep in non-human primates

DEFF Research Database (Denmark)

Yao, Dongyuan; Lavigne, Gilles J.; Lee, Jye-Chang

2013-01-01

Study Objective: To test the hypothesis that the reflex and corticobulbar motor excitability of jaw muscles is reduced during sleep. Design: Polysomnographic recordings in the electrophysiological study. Setting: University sleep research laboratories. Participants and Interventions: The reflex a...

Do reflex seizures and spontaneous seizures form a continuum? - triggering factors and possible common mechanisms.

Science.gov (United States)

Irmen, Friederike; Wehner, Tim; Lemieux, Louis

2015-02-01

Recent changes in the understanding and classification of reflex seizures have fuelled a debate on triggering mechanisms of seizures and their conceptual organization. Previous studies and patient reports have listed extrinsic and intrinsic triggers, albeit their multifactorial and dynamic nature is poorly understood. This paper aims to review literature on extrinsic and intrinsic seizure triggers and to discuss common mechanisms among them. Among self-reported seizure triggers, emotional stress is most frequently named. Reflex seizures are typically associated with extrinsic sensory triggers; however, intrinsic cognitive or proprioceptive triggers have also been assessed. The identification of a trigger underlying a seizure may be more difficult if it is intrinsic and complex, and if triggering mechanisms are multifactorial. Therefore, since observability of triggers varies and triggers are also found in non-reflex seizures, the present concept of reflex seizures may be questioned. We suggest the possibility of a conceptual continuum between reflex and spontaneous seizures rather than a dichotomy and discuss evidence to the notion that to some extent most seizures might be triggered. Copyright © 2014 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

The Danish CSR Reporting Requirement as Reflexive Law

DEFF Research Database (Denmark)

Buhmann, Karin

2013-01-01

With effect for financial years beginning January 2009 or later, the Danish Financial Statements Act and related governmental regulations require large Danish companies and institutional investors to submit an annual Corporate Social Responsibility (CSR) report. Through application of reflexive law...

Energy and orientation dependence of electron-irradiation-induced defects in InP

International Nuclear Information System (INIS)

Sibille, A.; Suski, J.; LeRoux, G.

1984-01-01

The concentration of several electron-irradiation-induced deep defect levels in InP has been measured by deep-level transient spectroscopy (DLTS) as a function of electron energy. The dominant centers exhibit a threshold at about 100 keV, which clearly points to a primary production event by electron--phosphorus-atom collision. This unambiguous determination allowed a test of the recently proposed orientation dependence technique to find the nature of the sublattice involved in the collision process for III-V compounds. A good quantitative agreement is obtained with a hard-sphere model for secondary collisions if disorientation of the beam in the sample is taken into account. Other traps exhibit higher thresholds which correspond either to indium-atom displacements or to the involvement of secondary collisions in the production event

Reversal of functional disorders by aspiration, expiration and cough reflexes and their voluntary counterparts

Directory of Open Access Journals (Sweden)

Zoltan eTomori

2012-12-01

Full Text Available Agonal gasping provoked by asphyxia can save ~15% of mammals even from untreated ventricular fibrillation, but it fails to revive infants with sudden infant death syndrome. Our systematic study of airway reflexes in cats and other animals indicated that in addition to cough, there are 2 distinct airway reflexes that may contribute to auto-resuscitation. Gasp- and sniff-like spasmodic inspirations can be elicited by nasopharyngeal stimulation, strongly activating the brainstem generator for inspiration, which is also involved in the control of gasping. This aspiration reflex (AspR is characterized by spasmodic inspiration without subsequent active expiration and can be elicited during agonal gasping, caused by brainstem trans-sections in cats. Stimulation of the larynx can activate the generator for expiration to evoke the expiration reflex, manifesting with prompt expiration without preceding inspiration. Stimulation of the oro-pharynx and lower airways provokes the cough reflex which results from activating of both generators. The powerful potential of the AspR resembling auto-resuscitation by gasping can influence the control mechanisms of vital functions, mediating reversal of various functional disorders.The AspR in cats interrupted hypoxic apnea, laryngo- and bronchospasm, apneusis and even transient asphyxic coma, and can normalize various hypo- and hyper-functional disorders. Introduction of a nasogastric catheter evoked similar spasmodic inspirations in premature infants and interrupted hiccough attacks in adults. Coughing on demand can prevent anaphylactic shock and resuscitate the pertinent subject. Sniff representing nasal inspiratory pressure and maximal inspiratory and expiratory pressures are voluntary counterparts of airway reflexes, and are useful for diagnosis and therapy of various cardio-respiratory and neuromuscular disorders.

Ontogeny of mouse vestibulo-ocular reflex following genetic or environmental alteration of gravity sensing.

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Mathieu Beraneck

Full Text Available The vestibular organs consist of complementary sensors: the semicircular canals detect rotations while the otoliths detect linear accelerations, including the constant pull of gravity. Several fundamental questions remain on how the vestibular system would develop and/or adapt to prolonged changes in gravity such as during long-term space journey. How do vestibular reflexes develop if the appropriate assembly of otoliths and semi-circular canals is perturbed? The aim of present work was to evaluate the role of gravity sensing during ontogeny of the vestibular system. In otoconia-deficient mice (ied, gravity cannot be sensed and therefore maculo-ocular reflexes (MOR were absent. While canals-related reflexes were present, the ied deficit also led to the abnormal spatial tuning of the horizontal angular canal-related VOR. To identify putative otolith-related critical periods, normal C57Bl/6J mice were subjected to 2G hypergravity by chronic centrifugation during different periods of development or adulthood (Adult-HG and compared to non-centrifuged (control C57Bl/6J mice. Mice exposed to hypergravity during development had completely normal vestibulo-ocular reflexes 6 months after end of centrifugation. Adult-HG mice all displayed major abnormalities in maculo-ocular reflexe one month after return to normal gravity. During the next 5 months, adaptation to normal gravity occurred in half of the individuals. In summary, genetic suppression of gravity sensing indicated that otolith-related signals might be necessary to ensure proper functioning of canal-related vestibular reflexes. On the other hand, exposure to hypergravity during development was not sufficient to modify durably motor behaviour. Hence, 2G centrifugation during development revealed no otolith-specific critical period.

[Spasm of the near reflex. Treatment with botulinum toxin].

Science.gov (United States)

Merino, P; Rojas, P; Gómez de Liaño, P; Franco Iglesias, G

2015-05-01

A 38-year old female with diplopia and esotropia, with limitation of ocular abduction in both eyes, with full abduction after doll's head rotation also being observed. She was diagnosed with spasm of the near reflex. Treatment with injections of botulinum toxin in both medial rectus has temporally resolved the convergence spasm. Near reflex spasm is characterized as miosis, pseudomyopia, and convergent strabismus that lead to diplopia, blurred vision, headache, and variable, progressive, and intermittent esotropia. As the spasm worsens there will be limited ocular versions and ductions simulating a sixth nerve palsy. Botulinum toxin may be effective in some cases. Copyright © 2013 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

When he can also be she: An ERP study of reflexive pronoun resolution in written Mandarin Chinese

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Jui-Ju eSu

2016-02-01

Full Text Available The gender information in written Chinese third person pronouns is not symmetrically encoded: the character for he (他, with semantic radical 人, meaning human is used as a default referring to every individual, while the character for she (她, with semantic radical 女, meaning woman indicates females only. This critical feature could result in different patterns of processing of gender information in text, but this is an issue that has seldom been addressed in psycholinguistics. In Chinese, the written forms of the reflexive pronouns are composed of a pronoun plus the reflexive 自己/self (他自己/himself and 她自己/herself. The present study focuses on how such gender specificity interacts with the gender type of an antecedent, whether definitional (proper name or stereotypical (stereotypical role noun during reflexive pronoun resolution. In this event-related potential (ERP study, gender congruity between a reflexive pronoun and its antecedent was studied by manipulating the gender type of antecedents and the gender specificity of reflexive pronouns (default: 他自己/himself vs. specific: 她自己/herself. Results included a P200 attention related congruity effect for 他自己/himself and a P600 integration difficulty congruity effect for 她自己/herself. Reflexive pronoun specificity independently affected the P200 and N400 components. These results highlight the role of 他自己/himself as a default applicable to both genders and indicate that only the processing of 她自己/herself supports a two-stage model for anaphor resolution. While both reflexive pronouns are evaluated at the bonding stage, the processing of the gender-specific reflexive pronoun is completed in the resolution stage.

Child-Computer Interaction at the Beginner Stage of Music Learning: Effects of Reflexive Interaction on Children's Musical Improvisation.

Science.gov (United States)

Addessi, Anna Rita; Anelli, Filomena; Benghi, Diber; Friberg, Anders

2017-01-01

In this article children's musical improvisation is investigated through the "reflexive interaction" paradigm. We used a particular system, the MIROR-Impro, implemented in the framework of the MIROR project (EC-FP7), which is able to reply to the child playing a keyboard by a "reflexive" output, mirroring (with repetitions and variations) her/his inputs. The study was conducted in a public primary school, with 47 children, aged 6-7. The experimental design used the convergence procedure, based on three sample groups allowing us to verify if the reflexive interaction using the MIROR-Impro is necessary and/or sufficient to improve the children's abilities to improvise. The following conditions were used as independent variables: to play only the keyboard, the keyboard with the MIROR-Impro but with not-reflexive reply, the keyboard with the MIROR-Impro with reflexive reply. As dependent variables we estimated the children's ability to improvise in solos, and in duets. Each child carried out a training program consisting of 5 weekly individual 12 min sessions. The control group played the complete package of independent variables; Experimental Group 1 played the keyboard and the keyboard with the MIROR-Impro with not-reflexive reply; Experimental Group 2 played only the keyboard with the reflexive system. One week after, the children were asked to improvise a musical piece on the keyboard alone (Solo task), and in pairs with a friend (Duet task). Three independent judges assessed the Solo and the Duet tasks by means of a grid based on the TAI-Test for Ability to Improvise rating scale. The EG2, which trained only with the reflexive system, reached the highest average results and the difference with EG1, which did not used the reflexive system, is statistically significant when the children improvise in a duet. The results indicate that in the sample of participants the reflexive interaction alone could be sufficient to increase the improvisational skills, and necessary

Neural reflex pathways in intestinal inflammation: hypotheses to viable therapy.

Science.gov (United States)

Willemze, Rose A; Luyer, Misha D; Buurman, Wim A; de Jonge, Wouter J

2015-06-01

Studies in neuroscience and immunology have clarified much of the anatomical and cellular basis for bidirectional interactions between the nervous and immune systems. As with other organs, intestinal immune responses and the development of immunity seems to be modulated by neural reflexes. Sympathetic immune modulation and reflexes are well described, and in the past decade the parasympathetic efferent vagus nerve has been added to this immune-regulation network. This system, designated 'the inflammatory reflex', comprises an afferent arm that senses inflammation and an efferent arm that inhibits innate immune responses. Intervention in this system as an innovative principle is currently being tested in pioneering trials of vagus nerve stimulation using implantable devices to treat IBD. Patients benefit from this treatment, but some of the working mechanisms remain to be established, for instance, treatment is effective despite the vagus nerve not always directly innervating the inflamed tissue. In this Review, we will focus on the direct neuronal regulatory mechanisms of immunity in the intestine, taking into account current advances regarding the innervation of the spleen and lymphoid organs, with a focus on the potential for treatment in IBD and other gastrointestinal pathologies.

Cultural Reflexivity and the Nostalgia for Glocal Consumer Culture: Insights from a Multicultural Multiple Migration Context

DEFF Research Database (Denmark)

Emontspool, Julie; Kjeldgaard, Dannie

2013-01-01

Purpose – The purpose of this article is to investigate consumption discourses in contexts characterized by multiple cultures and intercultural contacts, as multicultural contacts and multiple migrations challenge existing consumer acculturation models based on a dualistic process of acculturation....... This chapter explores empirically the character of cultural reflexivity and its expression in consumers’ discourses. Given that nostalgia is one prominent dimension of the migration conceptualization, we seek to understand how the role of nostalgia changes in contexts where consumers are decreasingly...... – On the basis of these findings, the article discusses cultural reflexivity in terms of naturalization and cultivation narratives (Wilk, 1999), proposing shifts between reflexive and routinized consumption practices as basis for consumers’ cultural reflexivity. Originality/value of chapter – The contribution...

The late blink reflex response abnormality due to lesion of the lateral tegmental field

NARCIS (Netherlands)

Aramideh, M.; Ongerboer de Visser, B.W.; Koelman, J.H.T.M.; Majoie, C.B.L.; Holstege, G.

We report on a blink reflex abnormality observed in two patients, which provides additional information on the central pathways mediating this reflex. Autopsy was performed in one patient and MRI in the other: In the first patient there was a small lesion at the dorsal middle third of the lateral

The late blink reflex response abnormality due to lesion of the lateral tegmental field

NARCIS (Netherlands)

Aramideh, M.; Ongerboer de Visser, B. W.; Koelman, J. H.; Majoie, C. B.; Holstege, G.

1997-01-01

We report on a blink reflex abnormality observed in two patients, which provides additional information on the central pathways mediating this reflex. Autopsy was performed in one patient and MRI in the other. In the first patient there was a small lesion at the dorsal middle third of the lateral

Reflexivity and the Politics of Knowledge: Researchers as "Brokers" and "Translators" of Educational Development

Science.gov (United States)

Sriprakash, Arathi; Mukhopadhyay, Rahul

2015-01-01

This paper interrogates the ways in which "reflexivity" has proliferated as a normative methodological discourse in the field of international and comparative education. We argue that the dominant approach to reflexivity foregrounds the standpoints of researchers and their subjects in a way that does not attend to the situated,…

Automethodology: Tracing a Home for Praxis-Oriented Ethnography

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Sandra L. Pensoneau-Conway

2011-12-01

Full Text Available The authors trace the development of ethnographic practices according to the methodological assumptions of ethnographers within different historical periods. As communication scholars, the authors find Calvin O. Schrag's conceptualization of the self to be informative and advantageous for navigating an ethnographic sense of ‘self in the current status of the methodological contestation. Borrowing from Schrag’ s work, which focuses on communicative praxis in understanding the self, this article explores an innovative methodological framework called automethodology. By examining the deployment and emplotment of the self within the automethods of autobiography, autoethnography, narrative co-construction, community autoethnography, critical complete-member ethnography, reflexive ethnography, autoperformance, and layered account, the authors develop epistemological foundations for praxis-oriented ethnographers. Throughout this journey, the authors end up situating themselves in a place they consider home-in the practices of automethodology.

Place based teaching in the visual arts and art education

DEFF Research Database (Denmark)

Andersen, Kirsten Bak

Contemporary Art and three orientations in visual culture pedagogy: Perception, Relational and Reflexive practice.......Contemporary Art and three orientations in visual culture pedagogy: Perception, Relational and Reflexive practice....

For reflexivity as an epistemic criterion of ontological coherence and virtuous social theorizing.

Science.gov (United States)

Bouzanis, Christoforos

2017-12-01

This article offers an approach that combines, on the one hand, the philosophical notion of reflexivity, which is related to the ideas of self-reference and paradox, and, on the other hand, the sociological discussion of epistemic reflexivity as a problem of coherence, which was mainly initiated by certain branches of ethnomethodology and social constructionism. This combinatory approach argues for reflexivity as an epistemic criterion of ontological coherence , which suggests that social ontologies should account for the possibility of self-reflective subjectivity - for otherwise they result in a paradoxical conclusion according to which a social scientist reflects on her or his ontological commitments even though these commitments deny her or him the capacity for self-reflection . This analysis presupposes that all human sciences are categorically premised on social ontologies; and it argues for an analytical distinction between self-reflection, which refers to the agential capacity for reflecting on one's own commitments, and the epistemic criterion of reflexivity hereby proposed. These two analytically distinct though interdependent socio-theoretical concepts are frequently conflated in the literature; thus, this article also aims at a 'clearing of the ground' that can be of categorical use to the human sciences.

The effect of titrated fentanyl on suppressed cough reflex in healthy adult volunteers.

Science.gov (United States)

Kelly, H E; Shaw, G M; Brett, C N; Greenwood, F M; Huckabee, M L

2016-05-01

Cough suppression is part of the pharmacodynamic profile of opioids. We investigated the impact of clinical doses of fentanyl on suppressing the cough reflex. Thirteen volunteers received 2 μg.kg(-1) of fentanyl in a divided administration protocol. Three minutes after each administration and at 10 min intervals during washout, suppressed cough reflex testing with nebulised citric acid was performed and compared with fentanyl effect-site concentration. Mean (SD) citric acid concentration provoking cough increased from 0.5 (0.28) mol.l(-1) at baseline to 1.2 (0.50) mol.l(-1) after 2 μg.kg(-1) of fentanyl (p = 0.01). Mean (SD) fentanyl effect-site concentration after the final dose of fentanyl was 1.89 (0.05) ng.ml(-1) . A strong positive correlation was found between suppressed cough reflex thresholds and fentanyl effect-site concentrations during both fentanyl administration and washout phases of the study (r(2) = 0.79, p = 0.01). The mean (SD) length of time for return of suppressed cough response was 44.6 (18.8) min. Clinically relevant doses of fentanyl produced cough reflex suppression in healthy volunteers. © 2016 The Association of Anaesthetists of Great Britain and Ireland.

F response and H reflex analysis of physiological unity of gravity and antigravity muscles in man.

Science.gov (United States)

García, H A; Fisher, M A

1977-01-01

Observational differences between reflex (H reflex) and antidromic (F response) activation of segmental motoneurons by a peripheral electrical stimulus are described. In contrast to H reflexes, the percentage of F responses found after a series of stimuli is directly related to the pick-up field of the recording electrode consistent with this response being due to the variable activation of a small fraction of the available motoneuron pool. Despite the differing physiological mechanisms, both F responses and H reflexes can be used to demonstrate similar relative "central excitatory states" for antigravity muscles (i.e. extensors in the lower extremity and flexors in the upper extremity) and their antagonist gravity muscles. H reflexes were elicited not only in their usual location in certain antigravity muscles but also in unusual locations by length/tension changes in agonist and antagonist groups as well as by passive stretch. The data argue for the physiological unity of similarly acting gravity and antigravity muscles as well as supporting a meaningful role of group II afferents in normal segmental motoneuron pool excitability.

Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord

Science.gov (United States)

Danner, Simon M.; Freundl, Brigitta; Binder, Heinrich; Mayr, Winfried; Rattay, Frank; Minassian, Karen

2015-01-01

In individuals with motor-complete spinal cord injury, epidural stimulation of the lumbosacral spinal cord at 2 Hz evokes unmodulated reflexes in the lower limbs, while stimulation at 22–60 Hz can generate rhythmic burstlike activity. Here we elaborated on an output pattern emerging at transitional stimulation frequencies with consecutively elicited reflexes alternating between large and small. We analyzed responses concomitantly elicited in thigh and leg muscle groups bilaterally by epidural stimulation in eight motor-complete spinal cord-injured individuals. Periodic amplitude modulation of at least 20 successive responses occurred in 31.4% of all available data sets with stimulation frequency set at 5–26 Hz, with highest prevalence at 16 Hz. It could be evoked in a single muscle group only but was more strongly expressed and consistent when occurring in pairs of antagonists or in the same muscle group bilaterally. Latencies and waveforms of the modulated reflexes corresponded to those of the unmodulated, monosynaptic responses to 2-Hz stimulation. We suggest that the cyclical changes of reflex excitability resulted from the interaction of facilitatory and inhibitory mechanisms emerging after specific delays and with distinct durations, including postactivation depression, recurrent inhibition and facilitation, as well as reafferent feedback activation. The emergence of large responses within the patterns at a rate of 5.5/s or 8/s may further suggest the entrainment of spinal mechanisms as involved in clonus. The study demonstrates that the human lumbosacral spinal cord can organize a simple form of rhythmicity through the repetitive activation of spinal reflex circuits. PMID:25904708

Abnormal reflex activation of hamstring muscles in dogs with cranial cruciate ligament rupture.

Science.gov (United States)

Hayes, Graham M; Granger, Nicolas; Langley-Hobbs, Sorrel J; Jeffery, Nick D

2013-06-01

The mechanisms underlying cranial cruciate ligament rupture (CCLR) in dogs are poorly understood. In this study hamstring muscle reflexes in response to cranial tibial translation were analysed to determine whether these active stabilisers of the stifle joint are differently activated in dogs with CCLR compared to control dogs. In a prospective clinical study reflex muscle activity from the lateral and medial hamstring muscles (biceps femoris and semimembranosus) was recorded using surface electrodes in control dogs (n=21) and dogs with CCLR (n=22). These electromyographic recordings were analysed using an algorithm previously validated in humans. The hamstring reflex was reliably and reproducibly recorded in normal dogs. Both a short latency response (SLR, 17.6±2.1ms) and a medium latency response (MLR, 37.7±2.7ms) could be identified. In dogs with unilateral CCLR, the SLR and MLR were not significantly different between the affected and the unaffected limbs, but the MLR latency of both affected and unaffected limbs in CCLR dogs were significantly prolonged compared to controls. In conclusion, the hamstring reflex can be recorded in dogs and the MLR is prolonged in dogs with CCLR. Since both affected and unaffected limbs exhibit prolonged MLR, it is possible that abnormal hamstring reflex activation is a mechanism by which progressive CCL damage may occur. The methodology allows for further investigation of the relationship between neuromuscular imbalance and CCLR or limitations in functional recovery following surgical intervention. Copyright © 2012 Elsevier Ltd. All rights reserved.

Highly effective strain-induced band-engineering of (111) oriented, direct-gap GeSn crystallized on amorphous SiO{sub 2} layers

Energy Technology Data Exchange (ETDEWEB)

Li, Haofeng; Wang, Xiaoxin; Liu, Jifeng, E-mail: Jifeng.Liu@dartmouth.edu [Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755 (United States)

2016-03-07

We demonstrate highly effective strain-induced band-engineering of (111) oriented direct-gap Ge{sub 1−x}Sn{sub x} thin films (0.074 < x < 0.085) crystallized on amorphous SiO{sub 2} towards 3D photonic integration. Due to a much smaller Poisson's ratio for (111) vs. (100) orientation, 0.44% thermally induced biaxial tensile strain reduces the direct-gap by 0.125 eV towards enhanced direct-gap semiconductor properties, twice as effective as the tensile strain in Ge(100) films. Correspondingly, the optical response is extended to λ = 2.8 μm. A dilatational deformation potential of a = −12.8 ± 0.8 eV is derived. These GeSn films also demonstrate high thermal stability, offering both excellent direct-gap optoelectronic properties and fabrication/operation robustness for integrated photonics.

Modification of Otolith Reflex Asymmetries Following Space Flight

Science.gov (United States)

Clarke, Andrew H.; Schoenfeld, Uwe; Wood, Scott J.

2011-01-01

We hypothesize that changes in otolith-mediated reflexes adapted for microgravity contribute to perceptual, gaze and postural disturbances upon return to Earth s gravity. Our goal was to determine pre- versus post-fight differences in unilateral otolith reflexes that reflect these adaptive changes. This study represents the first comprehensive examination of unilateral otolith function following space flight. Ten astronauts participated in unilateral otolith function tests three times pre-flight and up to four times after Shuttle flights from landing day through the subsequent 10 days. During unilateral centrifugation (UC, +/- 3.5cm at 400deg/s), utricular function was examined by the perceptual changes reflected by the subjective visual vertical (SVV) and by video-oculographic measurement of the otolith-mediated ocular counter-roll (OOR). Unilateral saccular reflexes were recorded by measurement of collic Vestibular Evoked Myogenic Potential (cVEMP). Although data from a few subjects were not obtained early post-flight, a general increase in asymmetry of otolith responses was observed on landing day relative to pre-flight baseline, with a subsequent reversal in asymmetry within 2-3 days. Recovery to baseline levels was achieved within 10 days. This fluctuation in the asymmetry measures appeared strongest for SVV, in a consistent direction for OOR, and in an opposite direction for cVEMP. These results are consistent with our hypothesis that space flight results in adaptive changes in central nervous system processing of otolith input. Adaptation to microgravity may reveal asymmetries in otolith function upon to return to Earth that were not detected prior to the flight due to compensatory mechanisms.

Influence of Substrate on Crystal Orientation of Large-Grained Si Thin Films Formed by Metal-Induced Crystallization

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Kaoru Toko

2015-01-01

Full Text Available Producing large-grained polycrystalline Si (poly-Si film on glass substrates coated with conducting layers is essential for fabricating Si thin-film solar cells with high efficiency and low cost. We investigated how the choice of conducting underlayer affected the poly-Si layer formed on it by low-temperature (500°C Al-induced crystallization (AIC. The crystal orientation of the resulting poly-Si layer strongly depended on the underlayer material: (100 was preferred for Al-doped-ZnO (AZO and indium-tin-oxide (ITO; (111 was preferred for TiN. This result suggests Si heterogeneously nucleated on the underlayer. The average grain size of the poly-Si layer reached nearly 20 µm for the AZO and ITO samples and no less than 60 µm for the TiN sample. Thus, properly electing the underlayer material is essential in AIC and allows large-grained Si films to be formed at low temperatures with a set crystal orientation. These highly oriented Si layers with large grains appear promising for use as seed layers for Si light-absorption layers as well as for advanced functional materials.

The comparison of application of two different frequencies of TENS on excitability of Hoffmann reflex

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Akbari M

2001-08-01

Full Text Available The aim of this investigation is to compare the effect of applying two transcutaneous electrical nerve stimulation (TENS current with different frequencies (2 Hz & 100 Hz on Hoffmann reflex recorded from gastrosoleus muscle of healthy people. Forty female subjects between 20 to 30 years of age were participated in this quasi-experimental design. Twenty of them were exposed to the 100 Hz current and the remaining 20 to 2 Hz current on dermatome S1 root. The excitability of the alpha motoneurone was measured by H-reflex amplitude (peak to peak max/2 before and after the application of the TENS current for 30 minutes. The reflex was recorded and at measured before (TO and after the application of TENS at different times (T1, T% and T10 up to 10 minutes. The mean values were compared by multiple paired T test (alpha=0.00825. The results indicate a considerable decrement in Hoffmann reflex amplitude after application of 100 Hz current in comarison with that of before the application. The effect last for 10 minutes after the TENS application, whereas the application of 2 Hz current results in increment of the Hoffmann reflex amplitude. The 5 and 10 minutes interval test dose not show any significance and the results were attenuated befor 5 minutes. As a conclusion high frequency of TENS (100 Hz has an inhibitory effect on excitability of alpha motor neurone reflex lasting for 10 minutes, while low frequency of TENS (2 Hz has an facilatory effect on the same motoneurone with short lasting effect.

Medial Olivocochlear Reflex Interneurons Are Located in the Posteroventral Cochlear Nucleus: A Kainic Acid Lesion Study in Guinea Pigs

OpenAIRE

De VENECIA, RONALD K.; LIBERMAN, M. CHARLES; GUINAN, JOHN J.; BROWN, M. CHRISTIAN

2005-01-01

The medial olivocochlear (MOC) reflex arc is probably a three-neuron pathway consisting of type I spiral ganglion neurons, reflex interneurons in the cochlear nucleus, and MOC neurons that project to the outer hair cells of the cochlea. We investigated the identity of MOC reflex interneurons in the cochlear nucleus by assaying their regional distribution using focal injections of kainic acid. Our reflex metric was the amount of change in the distortion product otoacoustic emission (at 2f1–f2)...

Modification of Spastic Stretch Reflexes at the Elbow by Flexion Synergy Expression in Individuals With Chronic Hemiparetic Stroke.

Science.gov (United States)

McPherson, Jacob G; Stienen, Arno H; Drogos, Justin M; Dewald, Julius P

2018-03-01

To systematically characterize the effect of flexion synergy expression on the manifestation of elbow flexor stretch reflexes poststroke, and to relate these findings to elbow flexor stretch reflexes in individuals without neurologic injury. Controlled cohort study. Academic medical center. Participants (N=20) included individuals with chronic hemiparetic stroke (n=10) and a convenience sample of individuals without neurologic or musculoskeletal injury (n=10). Participants with stroke were interfaced with a robotic device that precisely manipulated flexion synergy expression (by regulating shoulder abduction loading) while delivering controlled elbow extension perturbations over a wide range of velocities. This device was also used to elicit elbow flexor stretch reflexes during volitional elbow flexor activation, both in the cohort of individuals with stroke and in a control cohort. In both cases, the amplitude of volitional elbow flexor preactivation was matched to that generated involuntarily during flexion synergy expression. The amplitude of short- and long-latency stretch reflexes in the biceps brachii, assessed by electromyography, and expressed as a function of background muscle activation and stretch velocity. Increased shoulder abduction loading potentiated elbow flexor stretch reflexes via flexion synergy expression in the paretic arm. Compared with stretch reflexes in individuals without neurologic injury, paretic reflexes were larger at rest but were approximately equal to control muscles at matched levels of preactivation. Because flexion synergy expression modifies stretch reflexes in involved muscles, interventions that reduce flexion synergy expression may confer the added benefit of reducing spasticity during functional use of the arm. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

RefleX: X-ray absorption and reflection in active galactic nuclei for arbitrary geometries

Science.gov (United States)

Paltani, S.; Ricci, C.

2017-11-01

Reprocessed X-ray radiation carries important information about the structure and physical characteristics of the material surrounding the supermassive black hole (SMBH) in active galactic nuclei (AGN). We report here on a newly developed simulation platform, RefleX, which allows to reproduce absorption and reflection by quasi-arbitrary geometries. We show here the reliability of our approach by comparing the results of our simulations with existing spectral models such as pexrav, MYTorus and BNTorus. RefleX implements both Compton scattering on free electrons and Rayleigh scattering and Compton scattering on bound electrons. We show the effect of bound-electron corrections on a torus geometry simulated like in MYTorus. We release with this paper the RefleX executable, as well as RXTorus, a model that assumes absorption and reflection from a torus with a varying ratio of the minor to major axis of the torus. To allow major flexibility RXTorus is also distributed in three components: absorbed primary emission, scattered radiation and fluorescent lines. RXTorus is provided for different values of the abundance, and with (atomic configuration) or without (free-electron configuration) taking into account Rayleigh scattering and bound electrons. We apply the RXTorus model in both configurations on the XMM-Newton and NuSTAR spectrum of the Compton-thick AGN NGC 424 and find that the models are able to reproduce very well the observations, but that the assumption on the bound or free state of the electrons has significant consequences on the fit parameters. RefleX executable, user manual and example models are available at http://www.astro.unige.ch/reflex. A copy of the RefleX executable is also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/607/A31

H-reflexes reduce fatigue of evoked contractions after spinal cord injury.

Science.gov (United States)

Bergquist, Austin J; Wiest, Matheus J; Okuma, Yoshino; Collins, David F

2014-08-01

Neuromuscular electrical stimulation (NMES) over a muscle belly (mNMES) generates contractions predominantly through M-waves, while NMES over a nerve trunk (nNMES) can generate contractions through H-reflexes in people who are neurologically intact. We tested whether the differences between mNMES and nNMES are present in people with chronic motor-complete spinal cord injury and, if so, whether they influence contraction fatigue. Plantar-flexion torque and soleus electromyography were recorded from 8 participants. Fatigue protocols were delivered using mNMES and nNMES on separate days. nNMES generated contractions that fatigued less than mNMES. Torque decreased the least when nNMES generated contractions, at least partly through H-reflexes (n = 4 participants; 39% decrease), and torque decreased the most when contractions were generated through M-waves, regardless of NMES site (nNMES 71% decrease, n = 4; mNMES, 73% decrease, n = 8). nNMES generates contractions that fatigue less than mNMES, but only when H-reflexes contribute to the evoked contractions. Copyright © 2013 Wiley Periodicals, Inc.

ESO Reflex: A Graphical Workflow Engine for Data Reduction

Science.gov (United States)

Hook, R.; Romaniello, M.; Péron, M.; Ballester, P.; Gabasch, A.; Izzo, C.; Ullgrén, M.; Maisala, S.; Oittinen, T.; Solin, O.; Savolainen, V.; Järveläinen, P.; Tyynelä, J.

2008-08-01

Sampo {http://www.eso.org/sampo} (Hook et al. 2005) is a project led by ESO and conducted by a software development team from Finland as an in-kind contribution to joining ESO. The goal is to assess the needs of the ESO community in the area of data reduction environments and to create pilot software products that illustrate critical steps along the road to a new system. Those prototypes will not only be used to validate concepts and understand requirements but will also be tools of immediate value for the community. Most of the raw data produced by ESO instruments can be reduced using CPL {http://www.eso.org/cpl} recipes: compiled C programs following an ESO standard and utilizing routines provided by the Common Pipeline Library. Currently reduction recipes are run in batch mode as part of the data flow system to generate the input to the ESO VLT/VLTI quality control process and are also made public for external users. Sampo has developed a prototype application called ESO Reflex {http://www.eso.org/sampo/reflex/} that integrates a graphical user interface and existing data reduction algorithms. ESO Reflex can invoke CPL-based recipes in a flexible way through a dedicated interface. ESO Reflex is based on the graphical workflow engine Taverna {http://taverna.sourceforge.net} that was originally developed by the UK eScience community, mostly for work in the life sciences. Workflows have been created so far for three VLT/VLTI instrument modes ( VIMOS/IFU {http://www.eso.org/instruments/vimos/}, FORS spectroscopy {http://www.eso.org/instruments/fors/} and AMBER {http://www.eso.org/instruments/amber/}), and the easy-to-use GUI allows the user to make changes to these or create workflows of their own. Python scripts and IDL procedures can be easily brought into workflows and a variety of visualisation and display options, including custom product inspection and validation steps, are available.

Teacher education and the challenges of the reflexive practice

Directory of Open Access Journals (Sweden)

Maria Regina Peres

2013-06-01

Full Text Available This article approaches the importance of teacher practice and their initial and continuing education in the light of the challenges offered by the critical reflexive proposal. The aims of this study were to investigate the underlying assumptions regarding teachers’ current education and practice, to research and analyze the major difficulties found in the development of teaching practice, to comprehend and analyze the complexity inherent to the teacher’s performance in the initial years of elementary school. A bibliographic research and a qualitative research with elementary school teachers were therefore developed. The results indicate that although teachers believe the learning process to be continuous, they do not invest in this type of education. Furthermore it was found that teachers’ critical reflexive attitudes are blended with eproductivist attitudes.

Explicating Positionality: A Journey of Dialogical and Reflexive Storytelling

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Celina Carter MN

2014-02-01

Full Text Available Qualitative researchers must be aware of and explicit about their social background as well as political and ideological assumptions. To facilitate this awareness, we believe that researchers need to begin with their own story as they seek to understand the stories of others. Taking into account the vulnerable act of storytelling, it is salient to consider how to share personal narratives in an authentic way within academic settings. In this article, we share our process and reflections of engaging in reflexive and dialogical storytelling. The focus of the article is the re-storying of one researcher's experience as she and her research team explore her emotions and positionality prior to conducting research on First Nations men's narratives of identity. We integrate a series of methodological lessons concerning reflexivity throughout the re-storying.

The horizontal and vertical cervico-ocular reflexes of the rabbit.

Science.gov (United States)

Barmack, N H; Nastos, M A; Pettorossi, V E

1981-11-16

Horizontal and vertical cervico-ocular reflexes of the rabbit (HCOR, VCOR) were evoked by sinusoidal oscillation of the body about the vertical and longitudinal axes while the head was fixed. These reflexes were studied over a frequency range of 0.005-0.800 Hz and at stimulus amplitudes of +/- 10 degrees. When the body of the rabbit was rotated horizontally clockwise around the fixed head, clockwise conjugate eye movements were evoked. When the body was rotated about the longitudinal axis onto the right side, the right eye rotated down and the left eye rotated up. The mean gain of the HCOR (eye velocity/body velocity) rose from 0.21 and 0.005 Hz to 0.27 at 0.020 Hz and then declined to 0.06 at 0.3Hz. The gain of the VCOR was less than the gain of the HCOR by a factor of 2-3. The HCOR was measured separately and in combination with the horizontal vestibulo-ocular reflex (HVOR). These reflexes combine linearly. The relative movements of the first 3 cervical vertebrae during stimulation of the HCOR and VCOR were measured. For the HCOR, the largest angular displacement (74%) occurs between C1 and C2. For the VCOR, the largest relative angular displacement (45%) occurs between C2 and C3. Step horizontal clockwise rotation of the head and body (HVOR) evoked low velocity counterclockwise eye movements followed by fast clockwise (resetting) eye movements. Step horizontal clockwise rotation of the body about the fixed head (HCOR) evoked low velocity clockwise eye movements which were followed by fast clockwise eye movements. Step horizontal clockwise rotation of the head about the fixed body (HCOR + HVOR) evoked low velocity counterclockwise eye movements which were not interrupted by fast clockwise eye movements. These data provide further evidence for a linear combination of independent HCOR and HVOR signals.

Role of the cerebellum and the vestibular apparatus in regulation of orthostatic reflexes in the cat

Science.gov (United States)

Doba, N.; Reis, D. J.

1974-01-01

The contribution of the fastigial nucleus and the vestibular nerves (eighth cranial nerves) to the orthostatic reflexes in anesthetized, paralyzed cats was studied. Bilateral lesions of the rostral fastigial nucleus resulted in impairment of the reflex changes in blood pressure, femoral arterial flow, and resistance evoked by head-up tilting to 30 deg or 60 deg. The rostral fastigial nucleus, which might be triggered by the vestibular apparatus, appears to participate in concert with the baroreceptors in the initiation and possibly the maintenance of the orthostatic reflexes.

Review: Franz Breuer with Assistance of Barbara Dieris and Antje Lettau (2009. Reflexive Grounded Theory. Eine Einführung für die Forschungspraxis [Reflexive Grounded Theory: An Introduction to Research Praxis

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Sandra Da Rin

2010-03-01

Full Text Available This textbook by Franz BREUER, produced with the assistance of Barbara DIERIS and Antje LETTAU, is of interest more for the introduction it provides to reflexive research praxis than to grounded theory methodology. This means the subjectivity of the researcher is included in the research process as a decisive source of cognition. Reflexive grounded theory methodology is characterized by three elements that also structure the textbook. In the present review, I focus on two of these in detail: the approach to the research field based on ethnography, particular its epistemological prerequisites, and the inclusion of (self- reflexivity. The latter points to questions that are addressed at the end of this review. URN: urn:nbn:de:0114-fqs1002140

Atomistic simulation of orientation dependence in shock-induced initiation of pentaerythritol tetranitrate.

Science.gov (United States)

Shan, Tzu-Ray; Wixom, Ryan R; Mattsson, Ann E; Thompson, Aidan P

2013-01-24

The dependence of the reaction initiation mechanism of pentaerythritol tetranitrate (PETN) on shock orientation and shock strength is investigated with molecular dynamics simulations using a reactive force field and the multiscale shock technique. In the simulations, a single crystal of PETN is shocked along the [110], [001], and [100] orientations with shock velocities in the range 3-10 km/s. Reactions occur with shock velocities of 6 km/s or stronger, and reactions initiate through the dissociation of nitro and nitrate groups from the PETN molecules. The most sensitive orientation is [110], while [100] is the most insensitive. For the [001] orientation, PETN decomposition via nitro group dissociation is the dominant reaction initiation mechanism, while for the [110] and [100] orientations the decomposition is via mixed nitro and nitrate group dissociation. For shock along the [001] orientation, we find that CO-NO(2) bonds initially acquire more kinetic energy, facilitating nitro dissociation. For the other two orientations, C-ONO(2) bonds acquire more kinetic energy, facilitating nitrate group dissociation.

The optokinetic reflex as a tool for quantitative analyses of nervous system function in mice: application to genetic and drug-induced variation.

Directory of Open Access Journals (Sweden)

Hugh Cahill

2008-04-01

Full Text Available The optokinetic reflex (OKR, which serves to stabilize a moving image on the retina, is a behavioral response that has many favorable attributes as a test of CNS function. The OKR requires no training, assesses the function of diverse CNS circuits, can be induced repeatedly with minimal fatigue or adaptation, and produces an electronic record that is readily and objectively quantifiable. We describe a new type of OKR test apparatus in which computer-controlled visual stimuli and streamlined data analysis facilitate a relatively high throughput behavioral assay. We used this apparatus, in conjunction with infrared imaging, to quantify basic OKR stimulus-response characteristics for C57BL/6J and 129/SvEv mouse strains and for genetically engineered lines lacking one or more photoreceptor systems or with an alteration in cone spectral sensitivity. A second generation (F2 cross shows that the characteristic difference in OKR frequency between C57BL/6J and 129/SvEv is inherited as a polygenic trait. Finally, we demonstrate the sensitivity and high temporal resolution of the OKR for quantitative analysis of CNS drug action. These experiments show that the mouse OKR is well suited for neurologic testing in the context of drug discovery and large-scale phenotyping programs.

A cost minimisation and Bayesian inference model predicts startle reflex modulation across species

OpenAIRE

Bach, Dominik R

2015-01-01

In many species, rapid defensive reflexes are paramount to escaping acute danger. These reflexes are modulated by the state of the environment. This is exemplified in fear-potentiated startle, a more vigorous startle response during conditioned anticipation of an unrelated threatening event. Extant explanations of this phenomenon build on descriptive models of underlying psychological states, or neural processes. Yet, they fail to predict invigorated startle during reward anticipation and ins...

Parasympathetic nervous system dysfunction, as identified by pupil light reflex, and its possible connection to hearing impairment

OpenAIRE

Wang, Yang; Zekveld, Adriana A.; Naylor, Graham; Ohlenforst, Barbara; Jansma, Elise P.; Lorens, Artur; Lunner, Thomas; Kramer, Sophia E.

2016-01-01

Context\\ud Although the pupil light reflex has been widely used as a clinical diagnostic tool for autonomic nervous system dysfunction, there is no systematic review available to summarize the evidence that the pupil light reflex is a sensitive method to detect parasympathetic dysfunction. Meanwhile, the relationship between parasympathetic functioning and hearing impairment is relatively unknown.\\ud \\ud Objectives\\ud To 1) review the evidence for the pupil light reflex being a sensitive meth...

Soleus H-reflex excitability during pedaling post-stroke

DEFF Research Database (Denmark)

Schindler-Ivens, Sheila; Brown, David A.; Lewis, Gwyn N.

2008-01-01

A major contributor to impaired locomotion post-stroke is abnormal phasing of paretic muscle activity, but the mechanisms remain unclear. Previous studies have shown that, in the paretic limb of people post-stroke, Group Ia reflexes are abnormally elevated and fail to decrease in amplitude during...

Radiologic diagnosis of Hirschsprung's disease utilizing rectosphincteric reflex

Energy Technology Data Exchange (ETDEWEB)

Nagasaki, A.; Ikeda, K.; Hayashida, Y.

1984-09-01

Artificial balloon distension of the rectum caused a reflex opening of the anal canal as seen during barium enema in 10 out of 10 normal children and in 7 of 7 children with idiopathic constipation. Reflex opening of the anal canal was not observed in any of 15 children with proven Hirschsprung's disease. This lack of response was independent of the length of aganglionosis or previous diverting colostomy and corresponded to the fact that on manometric study the intraluminal pressure of the anal canal fell in normal children but not in the children with Hirschsprung's disease. This finding greatly improves the reliability of barium enema in the diagnosis of Hirschsprung's disease.

Alterations of brain network hubs in reflex syncope: Evidence from a graph theoretical analysis based on DTI.

Science.gov (United States)

Park, Bong Soo; Lee, Yoo Jin; Park, Jin-Han; Kim, Il Hwan; Park, Si Hyung; Lee, Ho-Joon; Park, Kang Min

2018-06-01

We evaluated global topology and organization of regional hubs in the brain networks and microstructural abnormalities in the white matter of patients with reflex syncope. Twenty patients with reflex syncope and thirty healthy subjects were recruited, and they underwent diffusion tensor imaging (DTI) scans. Graph theory was applied to obtain network measures based on extracted DTI data, using DSI Studio. We then investigated differences in the network measures between the patients with reflex syncope and the healthy subjects. We also analyzed microstructural abnormalities of white matter using tract-based spatial statistics analysis (TBSS). Measures of global topology were not different between patients with reflex syncope and healthy subjects. However, in reflex syncope patients, the strength measures of the right angular, left inferior frontal, left middle orbitofrontal, left superior medial frontal, and left middle temporal gyrus were lower than in healthy subjects. The betweenness centrality measures of the left middle orbitofrontal, left fusiform, and left lingual gyrus in patients were lower than those in healthy subjects. The PageRank centrality measures of the right angular, left middle orbitofrontal, and left superior medial frontal gyrus in patients were lower than those in healthy subjects. Regarding the analysis of the white matter microstructure, there were no differences in the fractional anisotropy and mean diffusivity values between the two groups. We have identified a reorganization of network hubs in the brain network of patients with reflex syncope. These alterations in brain network may play a role in the pathophysiologic mechanism underlying reflex syncope. © 2018 The Authors. Brain and Behavior published by Wiley Periodicals, Inc.

The effect of operant-conditioning balance training on the down-regulation of spinal H-reflexes in a spastic patient.

Science.gov (United States)

Hoseini, Najmeh; Koceja, David M; Riley, Zachary A

2011-10-24

Spasticity in chronic hemiparetic stroke patients has primarily been treated pharmacologically. However, there is increasing evidence that physical rehabilitation can help manage hyper-excitability of reflexes (hyperreflexia), which is a primary contributor to spasticity. In the present study, one chronic hemiparetic stroke patient operantly conditioned the soleus H-reflex while training on a balance board for two weeks. The results showed a minimal decrease in the Hmax-Mmax ratio for both the affected and unaffected limb, indicating that the H-reflex was not significantly altered with training. Alternatively, paired-reflex depression (PRD), a measure of history-dependent changes in reflex excitability, could be conditioned. This was evident by the rightward shift and decreased slope of reflex excitability in the affected limb. The non-affected limb decreased as well, although the non-affected limb was very sensitive to PRD initially, whereas the affected limb was not. Based on these results, it was concluded that PRD is a better index of hyperreflexia, and this measurement could be more informative of synapse function than simple H-reflexes. This study presents a novel and non-pharmacological means of managing spasticity that warrants further investigation with the potential of being translated to the clinic. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

The role of acupuncture in controlling the gagging reflex using a review of ten cases.

Science.gov (United States)

Fiske, J; Dickinson, C

2001-06-09

The gagging reflex is a physiological reaction which safeguards the airway from foreign bodies. In some people this response is exaggerated to the extent that the acceptance/provision of dental treatment is not possible. The aim of this paper is to review the role of acupuncture in controlling gagging as a safe, cheap, quick and relatively non-invasive technique. Ten people agreed to try ear acupuncture to control gagging during dental treatment. Prior to treatment the severity of gagging was assessed. Acupuncture needles were inserted into a specific anti-gagging point on each ear, manipulated briefly and left in situ. Dental treatment was then carried out and the effectiveness of the acupuncture in preventing gagging was assessed. After treatment, the needles were removed and the patient discharged. All acupuncture was carried out by a dentist trained in its use. Four people had a severe gag reflex which made treatment impossible and six had a very severe reflex which made treatment impossible and affected their dental attendance. Ear acupuncture completely controlled the gag reflex in eight cases (23 treatment episodes) and partially controlled the reflex in two cases (two treatment episodes). Dental treatment could be carried out in all cases and at all visits. The cost of materials was 0.2 pounds per person per visit. Additional clinical time was in the order of 2-3 minutes. There were no adverse reactions to the technique and, on all occasions, patients were fit to leave the surgery and travel home unaccompanied. Ear acupuncture was successful in controlling the gag reflex. It is a safe, quick, inexpensive and relatively noninvasive technique. A controlled clinical trial is required to investigate any placebo effect.

Working data together: the accountability and reflexivity of digital astronomical practice.

Science.gov (United States)

Hoeppe, Götz

2014-04-01

Drawing on ethnomethodology, this article considers the sequential work of astronomers who combine observations from telescopes at two observatories in making a data set for scientific analyses. By witnessing the induction of a graduate student into this work, it aims at revealing the backgrounded assumptions that enter it. I find that these researchers achieved a consistent data set by engaging diverse evidential contexts as contexts of accountability. Employing graphs that visualize data in conventional representational formats of observational astronomy, experienced practitioners held each other accountable by using an 'implicit cosmology', a shared (but sometimes negotiable) characterization of 'what the universe looks like' through these formats. They oriented to data as malleable, that is, as containing artifacts of the observing situation which are unspecified initially but can be defined and subsequently removed. Alternating between reducing data and deducing astronomical phenomena, they ascribed artifacts to local observing conditions or computational procedures, thus maintaining previously stabilized phenomena reflexively. As researchers in data-intensive sciences are often removed from the instruments that generated the data they use, this example demonstrates how scientists can achieve agreement by engaging stable 'global' data sets and diverse contexts of accountability, allowing them to bypass troubling features and limitations of data generators.

Particular features of conditioned electrodefensive reflex in white rats on background of constant magnetic field

Energy Technology Data Exchange (ETDEWEB)

Shust, I.V.; Galantyuk, S.I.; Cheretyanko, Yu.V.

Study of the influence of magnetic fields upon the higher nervous activity of man and animals has long been attracting the attention of researchers. It is indicated in the literature that magnetic fields inhibit development of conditioned reflexes in planarians, fishes, and mammals. However, there are data of opposite nature as well, indicating accelerated development of the avoidance reflex in animals exposed previously to a magnetic field. Researchers studied formation of a conditioned electrodefensive reflex (CER) in white rats exposed to a constant magnetic field (CMF), and the influence of a vitamin preparation - galascorbin - on formation of the CER in animals exposed to a CMF.

[Dry immersion effects on the mechanisms of metabolic-reflex regulation of hemodynamics during muscular work].

Science.gov (United States)

Bravyĭ, Ia R; Bersenev, E Iu; Missina, S S; Borovik, A S; Sharova, A P; Vinogradova, O L

2008-01-01

Effects of 4-d dry immersion on metabolic-reflex regulation of hemodynamics were evaluated during local static work (30% of maximum voluntary effort) of the talocrural extensors. One group of immersed test-subjects received low-frequency electrostimulation of leg muscles to offset the immersion effect on EMG of working muscles. Metabolic-reflex regulation was evaluated through comparison of cardiovascular responses to physical tests with and w/o post-exercise vascular occlusion. Immersion vaguely increased heart rate and reduced systolic arterial pressure in resting subjects; however, it did not have a distinct effect on arterial pressure and HR during muscular work or metabolic-reflex potentiation of hemodynamic shifts.

Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord

OpenAIRE

Hofstoetter, Ursula S.; Danner, Simon M.; Freundl, Brigitta; Binder, Heinrich; Mayr, Winfried; Rattay, Frank; Minassian, Karen

2015-01-01

In individuals with motor-complete spinal cord injury, epidural stimulation of the lumbosacral spinal cord at 2 Hz evokes unmodulated reflexes in the lower limbs, while stimulation at 22–60 Hz can generate rhythmic burstlike activity. Here we elaborated on an output pattern emerging at transitional stimulation frequencies with consecutively elicited reflexes alternating between large and small. We analyzed responses concomitantly elicited in thigh and leg muscle groups bilaterally by epidural...

A reflexive exploration of two qualitative data coding techniques

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Erik Blair

2016-01-01

Full Text Available In an attempt to help find meaning within qualitative data, researchers commonly start by coding their data. There are a number of coding systems available to researchers and this reflexive account explores my reflections on the use of two such techniques. As part of a larger investigation, two pilot studies were undertaken as a means to examine the relative merits of open coding and template coding for examining transcripts. This article does not describe the research project per se but attempts to step back and offer a reflexive account of the development of data coding tools. Here I reflect upon and evaluate the two data coding techniques that were piloted, and discuss how using appropriate aspects of both led to the development of my final data coding approach. My exploration found there was no clear-cut ‘best’ option but that the data coding techniques needed to be reflexively-aligned to meet the specific needs of my project. This reflection suggests that, when coding qualitative data, researchers should be methodologically thoughtful when they attempt to apply any data coding technique; that they do not assume pre-established tools are aligned to their particular paradigm; and that they consider combining and refining established techniques as a means to define their own specific codes. DOI: 10.2458/azu_jmmss.v6i1.18772DOI: 10.2458/azu_jmmss.v6i1.18772

Glutamatergic neurotransmission from melanopsin retinal ganglion cells is required for neonatal photoaversion but not adult pupillary light reflex.

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Anton Delwig

Full Text Available Melanopsin-expressing retinal ganglion cells (mRGCs in the eye play an important role in many light-activated non-image-forming functions including neonatal photoaversion and the adult pupillary light reflex (PLR. MRGCs rely on glutamate and possibly PACAP (pituitary adenylate cyclase-activating polypeptide to relay visual signals to the brain. However, the role of these neurotransmitters for individual non-image-forming responses remains poorly understood. To clarify the role of glutamatergic signaling from mRGCs in neonatal aversion to light and in adult PLR, we conditionally deleted vesicular glutamate transporter (VGLUT2 selectively from mRGCs in mice. We found that deletion of VGLUT2 in mRGCs abolished negative phototaxis and light-induced distress vocalizations in neonatal mice, underscoring a necessary role for glutamatergic signaling. In adult mice, loss of VGLUT2 in mRGCs resulted in a slow and an incomplete PLR. We conclude that glutamatergic neurotransmission from mRGCs is required for neonatal photoaversion but is complemented by another non-glutamatergic signaling mechanism for the pupillary light reflex in adult mice. We speculate that this complementary signaling might be due to PACAP neurotransmission from mRGCs.

Hypoxia Inducible Factors and Hypertension: Lessons from Sleep Apnea Syndrome

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Nanduri, Jayasri; Peng, Ying-Jie; Yuan, Guoxiang; Kumar, Ganesh K.; Prabhakar, Nanduri R.

2015-01-01

Systemic hypertension is one of the most prevalent cardiovascular diseases. Sleep disordered breathing (SDB) with recurrent apnea is a major risk factor for developing essential hypertension. Chronic intermittent hypoxia (CIH) is a hallmark manifestation of recurrent apnea. Rodent models patterned after the O2 profiles seen with SDB patients showed that CIH is the major stimulus for causing systemic hypertension. This article reviews the physiological and molecular basis of CIH-induced hypertension. Physiological studies have identified that augmented carotid body chemosensory reflex and the resulting increase in sympathetic nerve activity is a major contributor to CIH-induced hypertension. Analysis of molecular mechanisms revealed that CIH activates hypoxia-inducible factor (HIF)-1 and suppresses HIF-2- mediated transcription. Dysregulation of HIF-1- and HIF-2- mediated transcription leads to imbalance of pro-oxidant and anti-oxidant enzyme gene expression resulting in increased reactive species (ROS) generation in the chemosensory reflex which is central for developing hypertension. PMID:25772710

Activity in the primary somatosensory cortex induced by reflexological stimulation is unaffected by pseudo-information: a functional magnetic resonance imaging study.

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Miura, Naoki; Akitsuki, Yuko; Sekiguchi, Atsushi; Kawashima, Ryuta

2013-05-27

Reflexology is an alternative medical practice that produces beneficial effects by applying pressure to specific reflex areas. Our previous study suggested that reflexological stimulation induced cortical activation in somatosensory cortex corresponding to the stimulated reflex area; however, we could not rule out the possibility of a placebo effect resulting from instructions given during the experimental task. We used functional magnetic resonance imaging (fMRI) to investigate how reflexological stimulation of the reflex area is processed in the primary somatosensory cortex when correct and pseudo-information about the reflex area is provided. Furthermore, the laterality of activation to the reflexological stimulation was investigated. Thirty-two healthy Japanese volunteers participated. The experiment followed a double-blind design. Half of the subjects received correct information, that the base of the second toe was the eye reflex area, and pseudo-information, that the base of the third toe was the shoulder reflex area. The other half of the subjects received the opposite information. fMRI time series data were acquired during reflexological stimulation to both feet. The experimenter stimulated each reflex area in accordance with an auditory cue. The fMRI data were analyzed using a conventional two-stage approach. The hemodynamic responses produced by the stimulation of each reflex area were assessed using a general linear model on an intra-subject basis, and a two-way repeated-measures analysis of variance was performed on an intersubject basis to determine the effect of reflex area laterality and information accuracy. Our results indicated that stimulation of the eye reflex area in either foot induced activity in the left middle postcentral gyrus, the area to which tactile sensation to the face projects, as well as in the postcentral gyrus contralateral foot representation area. This activity was not affected by pseudo information. The results also indicate

Activity in the primary somatosensory cortex induced by reflexological stimulation is unaffected by pseudo-information: a functional magnetic resonance imaging study

Science.gov (United States)

2013-01-01

Background Reflexology is an alternative medical practice that produces beneficial effects by applying pressure to specific reflex areas. Our previous study suggested that reflexological stimulation induced cortical activation in somatosensory cortex corresponding to the stimulated reflex area; however, we could not rule out the possibility of a placebo effect resulting from instructions given during the experimental task. We used functional magnetic resonance imaging (fMRI) to investigate how reflexological stimulation of the reflex area is processed in the primary somatosensory cortex when correct and pseudo-information about the reflex area is provided. Furthermore, the laterality of activation to the reflexological stimulation was investigated. Methods Thirty-two healthy Japanese volunteers participated. The experiment followed a double-blind design. Half of the subjects received correct information, that the base of the second toe was the eye reflex area, and pseudo-information, that the base of the third toe was the shoulder reflex area. The other half of the subjects received the opposite information. fMRI time series data were acquired during reflexological stimulation to both feet. The experimenter stimulated each reflex area in accordance with an auditory cue. The fMRI data were analyzed using a conventional two-stage approach. The hemodynamic responses produced by the stimulation of each reflex area were assessed using a general linear model on an intra-subject basis, and a two-way repeated-measures analysis of variance was performed on an intersubject basis to determine the effect of reflex area laterality and information accuracy. Results Our results indicated that stimulation of the eye reflex area in either foot induced activity in the left middle postcentral gyrus, the area to which tactile sensation to the face projects, as well as in the postcentral gyrus contralateral foot representation area. This activity was not affected by pseudo information

Autonomic Dysfunction in Muscular Dystrophy: A Theoretical Framework for Muscle Reflex Involvement

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Scott Alan Smith

2014-02-01

Full Text Available Muscular dystrophies are a heterogeneous group of genetically inherited disorders whose most prominent clinical feature is progressive degeneration of skeletal muscle. In several forms of the disease, the function of cardiac muscle is likewise affected. The primary defect in this group of diseases is caused by mutations in myocyte proteins important to cellular structure and/or performance. That being stated, a growing body of evidence suggests that the development of autonomic dysfunction may secondarily contribute to the generation of skeletal and cardio-myopathy in muscular dystrophy. Indeed, abnormalities in the regulation of both sympathetic and parasympathetic nerve activity have been reported in a number of muscular dystrophy variants. However, the mechanisms mediating this autonomic dysfunction remain relatively unknown. An autonomic reflex originating in skeletal muscle, the exercise pressor reflex, is known to contribute significantly to the control of sympathetic and parasympathetic activity when stimulated. Given the skeletal myopathy that develops with muscular dystrophy, it is logical to suggest that the function of this reflex might also be abnormal with the pathogenesis of disease. As such, it may contribute to or exacerbate the autonomic dysfunction that manifests. This possibility along with a basic description of exercise pressor reflex function in health and disease are reviewed. A better understanding of the mechanisms that possibly underlie autonomic dysfunction in muscular dystrophy may not only facilitate further research but could also lead to the identification of new therapeutic targets for the treatment of muscular dystrophy.

Muscle weakness and lack of reflex gain adaptation predominate during post-stroke posture control of the wrist

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van der Helm Frans CT

2009-07-01

Full Text Available Abstract Background Instead of hyper-reflexia as sole paradigm, post-stroke movement disorders are currently considered the result of a complex interplay between neuronal and muscular properties, modified by level of activity. We used a closed loop system identification technique to quantify individual contributors to wrist joint stiffness during an active posture task. Methods Continuous random torque perturbations applied to the wrist joint by a haptic manipulator had to be resisted maximally. Reflex provoking conditions were applied i.e. additional viscous loads and reduced perturbation signal bandwidth. Linear system identification and neuromuscular modeling were used to separate joint stiffness into the intrinsic resistance of the muscles including co-contraction and the reflex mediated contribution. Results Compared to an age and sex matched control group, patients showed an overall 50% drop in intrinsic elasticity while their reflexive contribution did not respond to provoking conditions. Patients showed an increased mechanical stability compared to control subjects. Conclusion Post stroke, we found active posture tasking to be dominated by: 1 muscle weakness and 2 lack of reflex adaptation. This adds to existing doubts on reflex blocking therapy as the sole paradigm to improve active task performance and draws attention to muscle strength and power recovery and the role of the inability to modulate reflexes in post stroke movement disorders.

Maternal intake of cashew nuts accelerates reflex maturation and facilitates memory in the offspring.

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de Melo, Marília Ferreira Frazão Tavares; Pereira, Diego Elias; Sousa, Morgana Moura; Medeiros, Dilian Maise Ferreira; Lemos, Leanderson Tulio Marques; Madruga, Marta Suely; Santos, Nayane Medeiros; de Oliveira, Maria Elieidy Gomes; de Menezes, Camila Carolina; Soares, Juliana Késsia Barbosa

2017-10-01

Essential fatty acids, being indispensable during the stages of pregnancy, lactation and infancy influence the transmission of nerve impulses and brain function, and cashew nuts are a good source of these fatty acids. The objective of this study was to evaluate the effects of cashew nut consumption on reflex development, memory and profile of fatty acids of rat offspring treated during pregnancy and lactation. The animals were divided into three groups: Control (CONT), treated with 7% lipid derived from soybean oil; Normolipidic (NL) treated with 7% lipids derived from cashew nuts; and Hyperlipidic (HL) treated with 20% lipids derived from cashew nuts. Reflex ontogeny, Open-field habituation test and the Object Recognition Test (ORT) were assessed. The profile of fatty acids in the brain was carried out when the animals were zero, 21 and 60days old. Accelerated reflex maturation was observed in animals treated with cashew nuts (pacids and less Docosahexaenoic acid (DHA) in animals of the HL. The data showed that maternal consumption of cashew nuts can accelerate reflex maturation and facilitate memory in offspring when offered in adequate quantities. Copyright © 2017 ISDN. Published by Elsevier Ltd. All rights reserved.

Comparison of cough reflex testing with videoendoscopy in recently extubated intensive care unit patients.

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Kallesen, Molly; Psirides, Alex; Huckabee, Maggie-Lee

2016-06-01

Orotracheal intubation is known to impair cough reflex, but the validity of cough reflex testing (CRT) as a screening tool for silent aspiration in this population is unknown. One hundred and six participants in a tertiary-level intensive care unit (ICU) underwent CRT and videoendoscopic evaluation of swallowing (VES) within 24 hours of extubation. Cough reflex threshold was established for each participant using nebulized citric acid. Thirty-nine (37%) participants had an absent cough to CRT. Thirteen (12%) participants aspirated on VES, 9 (69%) without a cough response. Sensitivity of CRT to identify silent aspiration was excellent, but specificity was poor. There was a significant correlation between intubation duration and presence of aspiration on VES (P= .0107). There was no significant correlation between silent aspiration on VES and length of intubation, age, sex, diagnosis at intensive care unit admission, indication for intubation, Acute Physiology and Chronic Health Evaluation III score, morphine equivalent dose, or time of testing postextubation. Intensive care unit patients are at increased risk of aspiration in the 24 hours following extubation, and an impaired cough reflex is common. However, CRT overidentifies risk of silent aspiration in this population. Copyright © 2016 Elsevier Inc. All rights reserved.

A Study on Achilles Tendon Reflex in Normal Korean Persons and Various Thyroid Diseases

Energy Technology Data Exchange (ETDEWEB)

Kang, Jin Yung; Kim, Myung Duk; Lee, Hong Kyu; Lee, Jung Sang; Koh, Chang Soon; Lee, Mun Ho [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1978-03-15

Since Chaney reported the measurement of ankle jerk in Patients with myxedema for the first time, slowing of the reflex in myxedema has been well documented by many authors. Although its mechanisms have not been elucidated clearly, it has long been held in esteem by clinicians a near pathognomonic sign in myxedema. Possible mechanisms suggested include (a) abnormal activity of the central nervous system, (b) a disorder of muscle like that of myotonia (c) lowered temperature of the muscle, (d) increased viscosity of the muscle due to myxdematous infiltration and (e) part of a general slowing of all vital processes. The brisk reflex in thyrotoxicosis has also been noted to be characteristic. The recent development of several simple methods of quantitating the deep tendon reflex time has made its application an easy, rapid, inexpensive and accurate test in the results of our examinations on the Achilles tendon reflex (ATR) times in normal Koreans along their sexes, ages and in various thyroid diseases. Also we observed the changes of ATR times in the thyrotoxicosis and myxedema after the initiation of treatment and compared them with other thyroid function tests.

Effects of microinjection of scopolamine into the neostriatum of rats on performance of a food conditioned reflex at different levels of fixation.

Science.gov (United States)

Tikhonravov, D L; Shapovalova, K B; Dyubkacheva, T A

1997-01-01

Chronic experiments performed on 32 Sprague-Dawley rats using a movement-feeding operant reflex (Skinner box) model showed that microinjection of scopolamine into the neostriatum had effects on this reflex which depended on the stage of learning. In animals with weakly fixed reflexes (prior to reaching the stage of memory consolidation), bilateral microinjection of 0.3 microgram of scopolamine into the caudate nucleus completely inhibited the reflex for a prolonged period of time. When the operant habit was well fixed, bilateral microinjection of the same doses of scopolamine into the neostriatum had no effect on the reflex. These results suggest that the neostriatum cholinergic system is critically involved in forming the motor engram. The cholinergic system of the caudate nucleus either takes no part in realizing the well-fixed conditioned reflex movement response and/or other forebrain structures are involved in the reflex, compensating for the disturbance in neostriatal cholinergic function.

Vestibulo-ocular reflex and the head impulse test

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Eliana T. Maranhão

2012-12-01

Full Text Available The authors highlights the importance of the vestibulo-ocular reflex examination through the head impulse test as a diagnostic method for vestibular dysfunction as well as, and primarily, a bedside semiotic resource capable of differentiating between acute peripheral vestibulopathy and a cerebellar or brainstem infarction in emergency rooms.

Microgravity-induced modifications of the vestibuloocular reflex in Xenopus laevis tadpoles are related to development and the occurrence of tail lordosis.

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Horn, Eberhard R

2006-08-01

During space flights, tadpoles of the clawed toad Xenopus laevis occasionally develop upward bended tails (tail lordosis). The tail lordosis disappears after re-entry to 1g within a couple of days. The mechanisms responsible for the induction of the tail lordosis are unknown; physical conditions such as weight de-loading or physiological factors such as decreased vestibular activity in microgravity might contribute. Microgravity (microg) also exerts significant effects on the roll-induced vestibuloocular reflex (rVOR). The rVOR was used to clarify whether tail lordosis is caused by physiological factors, by correlating the occurrence of microg-induced tail lordosis with the extent of microg-induced rVOR modifications. Post-flight recordings from three space flights (D-2 Spacelab mission, STS-55 in 1993; Shuttle-to-Mir mission SMM-06, STS-84 in 1997; French Soyuz taxi flight Andromède to ISS in 2001) were analyzed in these experiments. At onset of microgravity, tadpoles were at stages 25-28, 33-36 or 45. Parameters tested were rVOR gain (ratio between the angular eye movement and the lateral 30 degrees roll) and rVOR amplitude (maximal angular postural change of the eyes during a 360 degrees lateral roll). A ratio of 22-84% of tadpoles developed lordotic tails, depending on the space flight. The overall observation was that the rVOR of tadpoles with normal tails was either not affected by microgravity, or it was enhanced. In contrast, the rVOR of lordotic animals always revealed a depression. In particular, during post-flight days 1-11, tadpoles with lordotic tails from all three groups (25-28, 33-36 and 45) showed a lower rVOR gain and amplitude than the 1g-controls. The rVOR gain and amplitude of tadpoles from the groups 25-28 and 33-36 that developed normal tails was not affected by microgravity while the rVOR of microg-tadpoles from the stage-45 group with normal tails revealed a significant rVOR augmentation. (1) the vestibular system of tadpoles with lordotic

The visual rooting reflex in individuals with autism spectrum disorders and co-occurring intellectual disability.

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de Bildt, Annelies; Mulder, Erik J; Van Lang, Natasja D J; de With, S A Jytte; Minderaa, Ruud B; Stahl, Sherin S; Anderson, George M

2012-02-01

The rooting reflex has long been studied by neurologists and developmentalists and is defined as an orientation toward tactile stimulation in the perioral region or visual stimulation near the face. Nearly, all previous reports of the visual rooting reflex (VRR) concern its presence in adults with neurological dysfunction. Previously, the VRR was reported to be present in a majority of individuals with autism and absent in control subjects. In the present larger study, we examined the presence of the VRR in 155 individuals with ASD and co-occurring Intellectual Disability (ASD + ID: autism, N = 60; Pervasive Developmental Disorder-Not Otherwise Specified (PDD_NOS), N = 95) and in a contrast group of 65 individuals with ID only. The VRR was present significantly more often in the ASD + ID (43.9%) group than in the ID-only group (24.6%; χ(1)(2)= 7.19; P = 0.007). Individuals with autism displayed a VRR more often (55.0%) than individuals with PDD-NOS (36.8%; χ(1)(2)= 4.92; P = 0.026) and individuals with ID only (24.6%; χ(1)(2)= 12.09; P = 0.001). A positive VRR was associated with lower IQ and adaptive functioning; in the ASD + ID group, ADI-R/ADOS domain scores were significantly higher in the VRR-positive subgroup. The results replicate and extend the finding of an increased occurrence of the VRR in autism. Although some association with IQ was observed, the VRR occurred substantially more often in the autism group compared with an intellectually disabled group, indicating some degree of specificity. Additional studies of infants and children with typical development, ASD and ID are needed to determine the utility of the VRR in ASD risk assessment and to elucidate possible specific behavioral associations. Copyright © 2011, International Society for Autism Research, Wiley-Liss, Inc.

Reflexive photography: an alternative method for documenting the learning process of cultural competence.

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Amerson, Roxanne; Livingston, Wade G

2014-04-01

This qualitative descriptive study used reflexive photography to evaluate the learning process of cultural competence during an international service-learning project in Guatemala. Reflexive photography is an innovative qualitative research technique that examines participants' interactions with their environment through their personal reflections on images that they captured during their experience. A purposive sample of 10 baccalaureate nursing students traveled to Guatemala, where they conducted family and community assessments, engaged in home visits, and provided health education. Data collection involved over 100 photographs and a personal interview with each student. The themes developed from the photographs and interviews provided insight into the activities of an international experience that influence the cognitive, practical, and affective learning of cultural competence. Making home visits and teaching others from a different culture increased students' transcultural self-efficacy. Reflexive photography is a more robust method of self-reflection, especially for visual learners.

Two ways to support reflexivity

DEFF Research Database (Denmark)

Adriansen, Hanne Kirstine; Knudsen, Hanne

2013-01-01

A current challenge to public managers is the lack of a well-defined role. How can master’s programmes prepare managers to live up to an undefined function? In this paper we argue that the lack of role description enhances the need for reflexivity and show how it is done at Master in Educational...... Management (MEM). MEM provides the participating managers with a new language that can give them a critical distance to the overload of expectations they meet at work and MEM teaches the participants to translate this new language into practice. The pedagogy used for this is labelled ‘experimental management...

Bernstein Lethargy Theorem and Reflexivity

OpenAIRE

Aksoy, Asuman Güven; Peng, Qidi

2018-01-01

In this paper, we prove the equivalence of reflexive Banach spaces and those Banach spaces which satisfy the following form of Bernstein's Lethargy Theorem. Let $X$ be an arbitrary infinite-dimensional Banach space, and let the real-valued sequence $\\{d_n\\}_{n\\ge1}$ decrease to $0$. Suppose that $\\{Y_n\\}_{n\\ge1}$ is a system of strictly nested subspaces of $X$ such that $\\overline Y_n \\subset Y_{n+1}$ for all $n\\ge1$ and for each $n\\ge1$, there exists $y_n\\in Y_{n+1}\\backslash Y_n$ such that ...

Oriented nanocomposites of ultrahigh-molecular-weight polyethylene and gold

NARCIS (Netherlands)

Heffels, W.; Bastiaansen, C.W.M.; Caseri, W.R.; Smith, P.

2000-01-01

Polymer nanocomposites were prepd. by mixing ultrahigh-mol.-wt. polyethylene and gold colloids coated with a self-assembled monolayer of dodecanethiol. Subsequently, these materials were oriented by solid state drawing which induced the formation of uniaxially oriented arrays of gold particles. As a

Caught in Uncertain Futures, Now: A Reflexive Moment

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Reyes, Reynaldo, III

2016-01-01

This reflexive vignette reveals the emotional risks of ethnographic work by a Chicano researcher, educator, and advocate doing work in the Texas-Mexico Borderlands, caught at the intersection of vulnerable Latina/o youth and their possible futures. Data in this creative piece are derived from field notes of one classroom observation from an…

Teaching Reflexivity: Undoing or Reinscribing Habits of Gender?

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Bondi, Liz

2009-01-01

This paper outlines an approach used in a course designed to teach reflexivity as a research skill and explores what kind of gender intervention such teaching might constitute. Although inspired by feminist debates about the complex power dynamics of research relationships, the course in question does not focus specifically on gender issues.…

PhD Students, Interculturality, Reflexivity, Community and Internationalisation

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Holliday, Adrian

2017-01-01

Interviews with a small group of doctoral students at a British university indicate that the students feel that the programme provides an environment within which they develop interculturality through reflexive engagement with the PhD community and in some cases with the participants in their research. Significant here is that they are…

Child–Computer Interaction at the Beginner Stage of Music Learning: Effects of Reflexive Interaction on Children’s Musical Improvisation

Science.gov (United States)

Addessi, Anna Rita; Anelli, Filomena; Benghi, Diber; Friberg, Anders

2017-01-01

In this article children’s musical improvisation is investigated through the “reflexive interaction” paradigm. We used a particular system, the MIROR-Impro, implemented in the framework of the MIROR project (EC-FP7), which is able to reply to the child playing a keyboard by a “reflexive” output, mirroring (with repetitions and variations) her/his inputs. The study was conducted in a public primary school, with 47 children, aged 6–7. The experimental design used the convergence procedure, based on three sample groups allowing us to verify if the reflexive interaction using the MIROR-Impro is necessary and/or sufficient to improve the children’s abilities to improvise. The following conditions were used as independent variables: to play only the keyboard, the keyboard with the MIROR-Impro but with not-reflexive reply, the keyboard with the MIROR-Impro with reflexive reply. As dependent variables we estimated the children’s ability to improvise in solos, and in duets. Each child carried out a training program consisting of 5 weekly individual 12 min sessions. The control group played the complete package of independent variables; Experimental Group 1 played the keyboard and the keyboard with the MIROR-Impro with not-reflexive reply; Experimental Group 2 played only the keyboard with the reflexive system. One week after, the children were asked to improvise a musical piece on the keyboard alone (Solo task), and in pairs with a friend (Duet task). Three independent judges assessed the Solo and the Duet tasks by means of a grid based on the TAI-Test for Ability to Improvise rating scale. The EG2, which trained only with the reflexive system, reached the highest average results and the difference with EG1, which did not used the reflexive system, is statistically significant when the children improvise in a duet. The results indicate that in the sample of participants the reflexive interaction alone could be sufficient to increase the improvisational

Suprasegmental neurophysiological monitoring with H reflex and TcMEP in spinal surgery. Transient loss due to hypotension. A case report

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Ángel Saponaro-González

Full Text Available Objective: H-reflex is a well known neurophysiological test used to evaluate sensory afferent and motor efferent impulses of S1 root. Despite its simplicity and feasibility, it is not used very often in the operating room. Methods: We report the case of a 16-year-old male patient who undergoes a surgical correction for a severe paralytic scoliosis (160°. On account of previous deficits, intraoperative neurophysiological monitoring was achieved through TcMEP and H-reflex. Results: Intraoperative neurophysiological monitoring (IONM showed a transient and simultaneous loss of bilateral TcMEP and H-reflex, coinciding with an abrupt hypotension during pedicle screw placement. After having dismissed mechanical injury and after increasing blood pressure, TcMEP and H-reflex were equivalent to those at baseline. Conclusions: The H-reflex is a classic neurophysiological test not used very frequently in the operating room. It is a feasible and reliable technique that can be helpful during spine surgery IONM, especially in patients with preexisting neurological deficits. Although simultaneous TcMEP and H-reflex monitoring has been previously described, to our knowledge, this is the first recorded case of a decline in both associated with abrupt hypotension. Keywords: Intraoperative neurophysiological monitoring, TcMEP, H-reflex, Scoliosis, Hypotension

The Cerebellum in Maintenance of a Motor Skill: A Hierarchy of Brain and Spinal Cord Plasticity Underlies H-Reflex Conditioning

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Wolpaw, Jonathan R.; Chen, Xiang Yang

2006-01-01

Operant conditioning of the H-reflex, the electrical analog of the spinal stretch reflex, is a simple model of skill acquisition and involves plasticity in the spinal cord. Previous work showed that the cerebellum is essential for down-conditioning the H-reflex. This study asks whether the cerebellum is also essential for maintaining…

VizieR Online Data Catalog: REFLEX II. Properties of the survey (Boehringer+ 2013)

Science.gov (United States)

Boehringer, H.; Chon, G.; Collins, C. A.; Guzzo, L.; Nowak, N.; Bobrovskyi, S.

2013-06-01

Like REFLEX I, the extended survey covers the southern sky outside the band of the Milky Way (|bII|>=20°) with regions around the Magellanic clouds excised (3 in LMC, 3 in SMC). The total survey area after this excision amounts to 4.24 steradian (or 13924°2) which corresponds to 33.75% of the sky. Different from REFLEX I, we use the refined RASS product RASS III (Voges et al. 1999, Cat. IX/10). (2 data files).

A Study on the Effects of Bee Venom Aqua-Acupuncture on Writhing Reflex

OpenAIRE

Jeong Sun-Hee; Koh Hyung-kyun; Park Dong-Suk

2000-01-01

Introduction:In spite of the use of Bee Venom aqua-acupuncture in the clinics, the scientific evaluation on effects is not enough. Bee Venom aqua-acupuncture is used according to the stimulation of acupuncture point and the chemical effects of Bee Venom. The aims of this study is to investigate the analgegic effects of the Bee Venom aqua-acupuncture, through the change of writhing reflex Materials and Methods:Pain animal model was used acetic acid method. The changes of writhing reflex of ...

Modulation of the Fibularis Longus Hoffmann Reflex and Postural Instability Associated With Chronic Ankle Instability

Science.gov (United States)

Kim, Kyung-Min; Hart, Joseph M.; Saliba, Susan A.; Hertel, Jay

2016-01-01

Context: Individuals with chronic ankle instability (CAI) present with decreased modulation of the Hoffmann reflex (H-reflex) from a simple to a more challenging task. The neural alteration is associated with impaired postural control, but the relationship has not been investigated in individuals with CAI. Objective: To determine differences in H-reflex modulation and postural control between individuals with or without CAI and to identify if they are correlated in individuals with CAI. Design: Descriptive laboratory study. Setting: Laboratory. Patients or Other Participants: A total of 15 volunteers with CAI (9 males, 6 females; age = 22.6 ± 5.8 years, height = 174.7 ± 8.1 cm, mass = 74.9 ± 12.8 kg) and 15 healthy sex-matched volunteers serving as controls (9 males, 6 females; age = 23.8 ± 5.8 years, height = 171.9 ± 9.9 cm, mass = 68.9 ± 15.5 kg) participated. Intervention(s): Maximum H-reflex (Hmax) and motor wave (Mmax) from the soleus and fibularis longus were recorded while participants lay prone and then stood in unipedal stance. We assessed postural tasks of unipedal stance with participants' eyes closed for 10 seconds using a forceplate. Main Outcome Measure(s): We normalized Hmax to Mmax to obtain Hmax : Mmax ratios for the 2 positions. For each muscle, H-reflex modulation was quantified using the percentage change scores in Hmax : Mmax ratios calculated from prone position to unipedal stance. Center-of-pressure data were used to compute 4 time-to-boundary variables. Separate independent-samples t tests were performed to determine group differences. Pearson product moment correlation coefficients were calculated between the modulation and balance measures in the CAI group. Results: The CAI group presented less H-reflex modulation in the soleus (t26 = −3.77, P = .001) and fibularis longus (t25 = −2.59, P = .02). The mean of the time-to-boundary minima in the anteroposterior direction was lower in the CAI group (t28 = −2.06, P = .048

Surface-Energy-Anisotropy-Induced Orientation Effects on RayleighInstabilities in Sapphire

Energy Technology Data Exchange (ETDEWEB)

Santala, Melissa; Glaeser, Andreas M.

2006-01-01

Arrays of controlled-geometry, semi-infinite pore channels of systematically varied crystallographic orientation were introduced into undoped m-plane (10{bar 1}0) sapphire substrates using microfabrication techniques and ion-beam etching and subsequently internalized by solid-state diffusion bonding. A series of anneals at 1700 C caused the breakup of these channels into discrete pores via Rayleigh instabilities. In all cases, channels broke up with a characteristic wavelength larger than that expected for a material with isotropic surface energy, reflecting stabilization effects due to surface-energy anisotropy. The breakup wavelength and the time required for complete breakup varied significantly with channel orientation. For most orientations, the instability wavelength for channels of radius R was in the range of 13.2R-25R, and complete breakup occurred within 2-10 h. To first order, the anneal times for complete breakup scale with the square of the breakup wavelength. Channels oriented along a <11{bar 2}0> direction had a wavelength of {approx} 139R, and required 468 h for complete breakup. Cross-sectional analysis of channels oriented along a <11{bar 2}0> direction showed the channel to be completely bounded by stable c(0001), r{l_brace}{bar 1}012{r_brace}, and s{l_brace}10{bar 1}1{r_brace} facets.

Effects of anticipated emotional category and temporal predictability on the startle reflex.

Science.gov (United States)

Parisi, Elizabeth A; Hajcak, Greg; Aneziris, Eleni; Nelson, Brady D

2017-09-01

Anticipated emotional category and temporal predictability are key characteristics that have both been shown to impact psychophysiological indices of defensive motivation (e.g., the startle reflex). To date, research has primarily examined these features in isolation, and it is unclear whether they have additive or interactive effects on defensive motivation. In the present study, the startle reflex was measured in anticipation of low arousal neutral, moderate arousal pleasant, and high arousal unpleasant pictures that were presented with either predictable or unpredictable timing. Linear mixed-effects modeling was conducted to examine startle magnitude across time, and the intercept at the beginning and end of the task. Across the entire task, the anticipation of temporally unpredictable (relative to predictable) pictures and emotional (relative to neutral) pictures potentiated startle magnitude, but there was no interaction between the two features. However, examination of the intercept at the beginning of the task indicated a Predictability by Emotional Category interaction, such that temporal unpredictability enhanced startle potentiation in anticipation of unpleasant pictures only. Examination of the intercept at the end of the task indicated that the effects of predictability and emotional category on startle magnitude were largely diminished. The present study replicates previous reports demonstrating that emotional category and temporal predictability impact the startle reflex, and provides novel evidence suggesting an interactive effect on defensive motivation at the beginning of the task. This study also highlights the importance of examining the time course of the startle reflex. Copyright © 2017 Elsevier B.V. All rights reserved.

Time-varying auditory gain control in response to double-pulse stimuli in harbour porpoises is not mediated by a stapedial reflex

Directory of Open Access Journals (Sweden)

Asger Emil Munch Schrøder

2017-04-01

Full Text Available Echolocating animals reduce their output level and hearing sensitivity with decreasing echo delays, presumably to stabilize the perceived echo intensity during target approaches. In bats, this variation in hearing sensitivity is formed by a call-induced stapedial reflex that tapers off over time after the call. Here, we test the hypothesis that a similar mechanism exists in toothed whales by subjecting a trained harbour porpoise to a series of double sound pulses varying in delay and frequency, while measuring the magnitudes of the evoked auditory brainstem responses (ABRs. We find that the recovery of the ABR to the second pulse is frequency dependent, and that a stapedial reflex therefore cannot account for the reduced hearing sensitivity at short pulse delays. We propose that toothed whale auditory time-varying gain control during echolocation is not enabled by the middle ear as in bats, but rather by frequency-dependent mechanisms such as forward masking and perhaps higher-order control of efferent feedback to the outer hair cells.

Practicing ethnography in migration-related detention centers: A reflexive account.

Science.gov (United States)

Esposito, Francesca

2017-01-01

Feminist scholars, as well as community psychologists, have advocated the role of reflexive engagement in the research process in order to challenge power relations. Moreover, the liberating potential of storytelling, especially when working with issues of diversity and marginalization, has been stressed. The purpose of this article is to reflect on an ethnographic work underway in the Identification and Expulsion Center-CIE of Ponte Galeria, Rome. How the researcher's identities, values, and experiences, alongside power and privilege, have influenced her positioning in the research setting and the relationships formed with the different setting members is the subject of discussion. In sharing the story of this work, the final intent is to contribute to the joint effort to foster a reflexive community psychology practice incorporating feminist goals and a dialogue about ethnography in community psychology.

The effect of (+)-lysergic acid diethylamide and other drugs on the carotid sinus reflex.

Science.gov (United States)

GINZEL, K H

1958-09-01

In cats, lysergic acid diethylamide (LSD) selectively blocked the reflex blood pressure rise following carotid chemoreceptor stimulation. It also reduced or abolished the chemoreceptor component of the pressor response to occlusion of the common carotid arteries. It did not inhibit the respiratory reflexes arising from the carotid chemoreceptors, unless spontaneous respiration was interfered with as a whole. The site of action was central, probably below the intercollicular level, regardless of whether the drug was administered by the intravenous route or into the lateral ventricle of the brain.LSD did not block the baroreceptor depressor reflex elicited by stimulation of one carotid sinus nerve. LSD frequently caused the systemic pressure to fall, even after vagotomy and atropine, and this effect might account for the occasional reduction of the baroreceptor component of the carotid occlusion response. On the other hand, no relationship was found between the action of LSD on vasomotor tone and its blocking effect on the chemoreceptor pressor reflex.Some derivatives of LSD produced effects similar to those described for LSD, whether or not they possessed a psychotropic action in man, and independently of their efficiency as antagonists to 5-hydroxytryptamine. Of a series of compounds chemically unrelated to LSD, chlorpromazine was found to block the chemoreceptor pressor rise after intracerebroventricular injection.

Reflexivity and the "Acting Subject": Conceptualizing the Unit of Analysis in Qualitative Health Research.

Science.gov (United States)

Shaw, James A

2016-07-06

The ways in which social scientists conceptualize the "reflexive" human subject have important consequences for how we go about our research. Whether and how we understand human subjects to be the authors of our own actions helps to structure what we say about health, health care, and the many other topics addressed in qualitative health research. In this article, I critically discuss assumptions of human reflexivity that are built into qualitative social science of health and medicine. I describe three alternative ways of understanding reflexive thought and human action derived from the theoretical works of Pierre Bourdieu, Bruno Latour, and George Lakoff and Mark Johnson, respectively. I then apply these three different ways of thinking about reflexivity and the acting subject to the analysis of an excerpt of participant observation data from a health services research study of transitions from hospital to home, illuminating the different kinds of analyses that arise from each perspective. I conclude with a call for social scientists to commit to the search for better ways of understanding the human subject, resisting the temptation to "settle" on theoretical statements that close down the path to more sophisticated conceptualizations of human thought and action. © The Author(s) 2016.

Deprivation and Recovery of Sleep in Succession Enhances Reflexive Motor Behavior.

Science.gov (United States)

Sprenger, Andreas; Weber, Frederik D; Machner, Bjoern; Talamo, Silke; Scheffelmeier, Sabine; Bethke, Judith; Helmchen, Christoph; Gais, Steffen; Kimmig, Hubert; Born, Jan

2015-11-01

Sleep deprivation impairs inhibitory control over reflexive behavior, and this impairment is commonly assumed to dissipate after recovery sleep. Contrary to this belief, here we show that fast reflexive behaviors, when practiced during sleep deprivation, is consolidated across recovery sleep and, thereby, becomes preserved. As a model for the study of sleep effects on prefrontal cortex-mediated inhibitory control in humans, we examined reflexive saccadic eye movements (express saccades), as well as speeded 2-choice finger motor responses. Different groups of subjects were trained on a standard prosaccade gap paradigm before periods of nocturnal sleep and sleep deprivation. Saccade performance was retested in the next morning and again 24 h later. The rate of express saccades was not affected by sleep after training, but slightly increased after sleep deprivation. Surprisingly, this increase augmented even further after recovery sleep and was still present 4 weeks later. Additional experiments revealed that the short testing after sleep deprivation was sufficient to increase express saccades across recovery sleep. An increase in speeded responses across recovery sleep was likewise found for finger motor responses. Our findings indicate that recovery sleep can consolidate motor disinhibition for behaviors practiced during prior sleep deprivation, thereby persistently enhancing response automatization. © The Author 2015. Published by Oxford University Press.

Dissociative identity disorder and prepulse inhibition of the acoustic startle reflex

Directory of Open Access Journals (Sweden)

Karl Yngvar Dale

2008-06-01

Full Text Available Karl Yngvar Dale1, Magne Arve Flaten1, Åke Elden1, Arne Holte21Department of Psychology, University of Tromsø, Norway; 2The Norwegian Institute of Public Health, Department of Mental Health, Oslo, Norway and University of Oslo, NorwayAbstract: A group of persons with dissociative identity disorder (DID was compared with a group of persons with other dissociative disorders, and a group of nondiagnosed controls with regard to prepulse inhibition (PPI of the acoustic startle reflex. The findings suggest maladaptive attentional processes at a controlled level, but not at a preattentive automatic level, in persons with DID. The prepulse occupied more controlled attentional resources in the DID group compared with the other two groups. Preattentive automatic processing, on the other hand, was normal in the DID group. Moreover, startle reflexes did not habituate in the DID group. In conclusion, increased PPI and delayed habituation is consistent with increased vigilance in individuals with DID. The present findings of reduced habituation of startle reflexes and increased PPI in persons with DID suggest the operation of a voluntary process that directs attention away from unpleasant or threatening stimuli. Aberrant voluntary attentional processes may thus be a defining characteristic in DID.Keywords: dissociation, DID, PPI, startle, habituation

Restrictions on reflexive and anti-causative readings in nominalizations and participles

Directory of Open Access Journals (Sweden)

Björn Lundquist

2011-10-01

Full Text Available This article discusses the absence of reflexive or self-caused readings in certain types of participles and de-verbal nominalizations, like the hanging of the suicidal patient and The suicidal patient was hanged yesterday. I argue that the “anti-reflexive” reading is not triggered by the presence of a subject PRO or pro, but rather by the absence of reflexive marking, i.e. overt marking that functions to recode lexically specified co-reference relations between the arguments of a predicate. I argue that the verb-phrase needs to be decomposed into at least two subparts/subevents and that each sub-event carries information about the participants involved in it (as in e.g. Pustejovsky 1995 and Ramchand 2008b. More specifically, arguments receive their thematic information from indices on verbal heads that introduces sub-events. Event-denoting nominalizations and participles in general inherit the event structure from the verb, i.e. the indices present in the verbal roots. I further argue that simple reflexives can be verbal heads, that are inserted as a last resort when there is a mismatch between the lexically stored information of a verb and the structure generated in the syntax. This article focuses on data from Swedish, but comparisons will be made with English.

The Influence of Gravito-Inertial Force on Sensorimotor Integration and Reflexive Responses

Science.gov (United States)

Curthoys, Ian S.; Guedry, Fred E.; Merfeld, Daniel M.; Watt, Doug G. D.; Tomko, David L.; Wade, Charles E. (Technical Monitor)

1994-01-01

Sensorimotor responses (e.g.. eye movements, spinal reflexes, etc depend upon the interpretation of the neural signals from the sensory systems. Since neural signals from the otoliths may represent either tilt (gravity) or translation (linear inertial force), sensory signals from the otolith organs are necessarily somewhat ambiguous. Therefore. the neural responses to changing otolith signals depend upon the context of the stimulation (e.g- active vs. passive, relative orientation of gravity, etc.) as well as upon other sensory signals (e.g., vision. canals, etc.). This session will focus upon the -role -played by the sensory signals from the otolith organs in producing efficient sensorimotor and behavioral responses. Curthoys will show the influence of the peripheral anatomy and physiology. Tomko will discuss the influence of tilt and translational otolith signals on eye movements. Merfeld will demonstrate the rate otolith organs play during the interaction of sensory signals from the canals and otoliths. Watt will show the influence of the otoliths on spinal/postural responses. Guedry will discuss the contribution of vestibular information to "path of movement"' perception and to the development of a stable vertical reference. Sensorimotor responses to the ambiguous inertial force stimulation provide an important tool to investigate how the nervous system processes patterns of sensory information and yields functional sensorimotor responses.

Effects of Bed Rest on Conduction Velocity of the Triceps Surae Stretch Reflex and Postural Control

Science.gov (United States)

Reschke, M. F.; Wood, S. J.; Cerisano, J. M.; Kofman, I. S.; Fisher, E. A.; Esteves, J. T.; Taylor, L. C.; DeDios, Y. E.; Harm, D. L.

2011-01-01

Despite rigorous exercise and nutritional management during space missions, astronauts returning from microgravity exhibit neuromuscular deficits and a significant loss in muscle mass in the postural muscles of the lower leg. Similar changes in the postural muscles occur in subjects participating in long-duration bed rest studies. These adaptive muscle changes manifest as a reduction in reflex conduction velocity during head-down bed rest. Because the stretch reflex encompasses both the peripheral (muscle spindle and nerve axon) and central (spinal synapse) components involved in adaptation to calf muscle unloading, it may be used to provide feedback on the general condition of neuromuscular function, and might be used to evaluate the effectiveness of countermeasures aimed at preserving muscle mass and function during periods of unloading. Stretch reflexes were measured on 18 control subjects who spent 60 to 90 days in continuous 6 deg head-down bed rest. Using a motorized system capable of rotating the foot around the ankle joint (dorsiflexion) through an angle of 10 degrees at a peak velocity of about 250 deg/sec, a stretch reflex was recorded from the subject's left triceps surae muscle group. Using surface electromyography, about 300 reflex responses were obtained and ensemble-averaged on 3 separate days before bed rest, 3 to 4 times in bed, and 3 times after bed rest. The averaged responses for each test day were examined for reflex latency and conduction velocity (CV) across gender. Computerized posturography was also conducted on these same subjects before and after bed rest as part of the standard measures. Peak-to-peak sway was measured during Sensory Organization Tests (SOTs) to evaluate changes in the ability to effectively use or suppress visual, vestibular, and proprioceptive information for postural control. Although no gender differences were found, a significant increase in reflex latency and a significant decrease in CV were observed during the bed

Study of the Reflex-Klystron

International Nuclear Information System (INIS)

Valencia A, R.

1981-01-01

The main purpose of this paper is the theoretical study and the development of a technique for designing. A low power Reflex-Klystron, in order to construct it in the graduated section laboratories of the Instituto Politecnico Nacional. It is pretended to attain a power of 15-45 m W in frequencies of 8-10 GHz with low acceleration potentials (300-400 V) and electric current of 15-25 m A; the device will be mechanically tuned and will have a fine tuning through the potential of the reflector (150-180 V negative with respect to the resonator). The International System of Units is used in this thesis. (Author)

Prepulse inhibition of the acoustic startle reflex in pigs and its disruption by D-amphetamine

DEFF Research Database (Denmark)

Lind, N. M.; Arnfred, S. M.; Hemmingsen, R. P.

2004-01-01

Prepulse inhibition (PPI) of the startle reflex is an operational measure of sensorimotor gating. The dopamine receptor agonist-mediated disruption of PPI in rats is widely used as a model of the sensorimotor gating deficiencies demonstrated in schizophrenia patients. As a possible tool for valid......Prepulse inhibition (PPI) of the startle reflex is an operational measure of sensorimotor gating. The dopamine receptor agonist-mediated disruption of PPI in rats is widely used as a model of the sensorimotor gating deficiencies demonstrated in schizophrenia patients. As a possible tool....../kg with a paradigm including two levels of prepulses (82 and 88dB) and a prepulse (PP) interval of 60 and 120ms. We found an average PPI of the startle reflex of 25.6% and both of the investigated PP intensities and PP intervals were equally effective in this PP-inhibitive paradigm. AMPH significantly disrupted PPI...... and, in spite of only the 0.5mg/kg dose proved statistically significant, the results indicate this to be dose-related. We have demonstrated the phenomenon of PPI of the startle reflex in landrace pigs and its disruption by d-amphetamine. Studies of sensorimotor gating defects could be a valuable...

Aprendizagem transformadora: a reflexão crítica na formação gerencial

Directory of Open Access Journals (Sweden)

Lisiane Quadrado Closs

Full Text Available Dadas as crescentes demandas por aprendizagens exigidas de gestores no atual contexto e a importância de seu papel para as organizações e a sociedade, sugere-se a necessidade de ampliar perspectivas para a educação gerencial. Esta vem recebendo críticas de correntes que destacam tanto a importância da reflexão como da reflexão crítica para a aprendizagem. Apresenta-se um levantamento de estudos brasileiros realizados sobre aprendizagem gerencial que corrobora a importância de ambas nos seus processos de aprendizagem, embora a reflexão crítica ainda seja pouco evidenciada no meio gerencial ou na educação de gestores. Propõe-se que a teoria da aprendizagem transformadora possa contribuir para a aprendizagem gerencial, suscitando reflexões críticas que favoreçam o pensamento autônomo e a liberação de pressupostos condicionados sobre o mundo, sobre os outros e sobre si, cruciais para o mundo do trabalho, para a cidadania e para a tomada de decisões morais.

Correlation of gastroesophageal reflex with aspiration pneumonia after surgery