WorldWideScience

Sample records for deg head-down tilt

  1. Back Pain During 6 deg Head-Down Tilt Approximates That During Actual Microgravity

    Science.gov (United States)

    Hutchinson, Karen J.; Watenpaugh, Donald E.; Murthy, Gita; Convertino, Victor A.; Hargens, Alan R.

    1995-01-01

    Astronauts often experience back pain during spaceflight. It was found that during spaceflight, 14 of 19 Shuttle crewmembers experienced back pain, which they described as dull (62%), localized to the lower back (500/6), and with an intensity of 2 on a 5-point scale. Further, the spine lengthens 4-7 cm in microgravity. Our objective was to compare back pain and spinal lengthening (body height increase) during simulated microgravity (6 deg head-down tilt, HDT) with the some parameters during actual microgravity. Eight male subjects completed a modified McGill pain questionnaire with intensity graded from zero (no pain) to five (intense and incapacitating gain) each day at 7.-OO pm during 2 d pre-HDT control, 16 d HDT, and I d post-HDT recovery periods. Only 2 subjects reported any pain after day 9 of HDT and during recov- ery. Heights increased 2.1 t 0.5 cm by day 3 of HDT and re- mained at that level until the end of the HDT period. Although spinal lengthening in space is greater than that during HDT, the HDT model approximates the level, type, distribution, and time course of back pain associated with actual microgrovity. In the HDT model, pain subsides in intensity when spinal lengthening stops. Therefore, back pain in actual and simulated microgravity may result from stretching of spinal andlor paraspinal tissues until a new spinal length is reached.

  2. Association Between Cardiovascular and Intraocular Pressure Changes in a 14-Day 6 deg Head Down Tilt (HDT) Bed Rest Study: Possible Implications in Retinal Anatomy

    Science.gov (United States)

    Cromwell, Ronita; Zanello, Susana; Yarbough, Patrice; Ploutz-Snyder, Robert; Taibbi, Giovanni; Vizzeri, Gianmarco

    2013-01-01

    Visual symptoms and intracranial pressure increase reported in astronauts returning from long duration missions in low Earth-orbit are thought to be related to fluid shifts within the body due to microgravity exposure. Because of this possible relation to fluid shifts, studies conducted in head-down tilt (HDT) bed rest are being monitored for potential changes in ocular health. These measures will also serve to determine whether HDT is a suitable ground-based analog to model subclinical cardiovascular and ocular changes that could shed light on the etiology of the VIIP syndrome observed in spaceflight. Sixteen healthy normotensive (12M, 4F, age range 29-54 years), non-smoker and normal weight subjects, volunteered to participate in a 14 day 6 deg head HDT study conducted at the NASA Flight Analogs Research Unit (FARU). This facility provides standard bed rest conditions (diet, wake/sleep time, time allowed in sunlight) during the time that the subjects stay at the FARU. Cardiovascular parameters were obtained in supine posture at BR-5, BR+0, and BR+3 and ocular monitoring was performed weekly. Intraocular pressure (IOP) increased from pre-bed rest BR-3) to the third day into bed rest (BR+3). Values reached a plateau towards the end of the bed rest phase (BR10) and decreased within the first three days of recovery (BR+2) returning to levels comparable to baseline at BR-3. As expected, most cardiovascular parameters were affected by 14 days of HDT bed rest. Plasma volume decreased as a result of bed rest but recovered to baseline levels by BR+3. Indications of cardiovascular deconditioning included increase in both systolic and diastolic blood pressure and heart rate, and a decrease in stroke volume and cardiac output between BR-5 and BR+3. Due to the experimental design of this study, we were not able to test the hypothesis that fluid shifts might be involved in the IOP increase during the bed rest phase, since cardiovascular measures were not available for those

  3. Gastrointestinal Physiology During Head Down Tilt Bedrest in Human Subjects

    Science.gov (United States)

    Vaksman, Z.; Guthienz, J.; Putcha, L.

    2008-01-01

    Introduction: Gastrointestinal (GI) motility plays a key role in the physiology and function of the GI tract. It directly affects absorption of medications and nutrients taken by mouth, in addition to indirectly altering GI physiology by way of changes in the microfloral composition and biochemistry of the GI tract. Astronauts have reported nausea, loss of appetite and constipation during space flight all of which indicate a reduction in GI motility and function similar to the one seen in chronic bed rest patients. The purpose of this study is to determine GI motility and bacterial proliferation during -6 degree head down tilt bed rest (HTD). Methods: Healthy male and female subjects between the ages of 25-40 participated in a 60 day HTD study protocol. GI transit time (GITT) was determined using lactulose breath hydrogen test and bacterial overgrowth was measured using glucose breath hydrogen test. H. Pylori colonization was determined using C13-urea breath test (UBIT#). All three tests were conducted on 9 days before HDT, and repeated on HDT days 2, 28, 58, and again on day 7 after HDT. Results: GITT increased during HTD compared to the respective ambulatory control values; GITT was significantly lower on day 7 after HTD. A concomitant increase in bacterial colonization was also noticed during HDT starting after approximately 28 days of HDT. However, H. Pylori proliferation was not recorded during HDT as indicated by UBIT#. Conclusion: GITT significantly decreased during HDT with a concomitant increase in the proliferation of GI bacterial flora but not H. pylori.

  4. Acute effects of head-down tilt and hypoxia on modulators of fluid homeostasis

    Science.gov (United States)

    Whitson, P. A.; Cintron, N. M.; Pietrzyk, R. A.; Scotto, P.; Loeppky, J. A.

    1994-01-01

    In an effort to understand the interaction between acute postural fluid shifts and hypoxia on hormonal regulation of fluid homeostasis, the authors measured the responses to head-down tilt with and without acute exposure to normobaric hypoxia. Plasma atrial natriuretic peptide (ANP), cyclic guanosine monophosphate (cGMP), cyclic adenosine monophosphate (cAMP), plasma aldosterone (ALD), and plasma renin activity (PRA) were measured in six healthy male volunteers who were exposed to a head-down tilt protocol during normoxia and hypoxia. The tilt protocol consisted of a 17 degrees head-up phase (30 minutes), a 28 degrees head-down phase (1 hour), and a 17 degrees head-up recovery period (2 hours, with the last hour normoxic in both experiments). Altitude equivalent to 14,828 ft was simulated by having the subjects breathe an inspired gas mixture with 13.9% oxygen. The results indicate that the postural fluid redistribution associated with a 60-minute head-down tilt induces the release of ANP and cGMP during both hypoxia and normoxia. Hypoxia increased cGMP, cAMP, ALD, and PRA throughout the protocol and significantly potentiated the increase in cGMP during head-down tilt. Hypoxia had no overall effect on the release of ANP, but appeared to attenuate the increase with head-down tilt. This study describes the acute effects of hypoxia on the endocrine response during fluid redistribution and suggests that the magnitude, but not the direction, of these changes with posture is affected by hypoxia.

  5. The effect of head-down tilt and water immersion on intracranial pressure in nonhuman primates

    Science.gov (United States)

    Keil, Lanny C.; Mckeever, Kenneth H.; Skidmore, Michael G.; Hines, John; Severs, Walter B.

    1992-01-01

    Intracranial pressure (ICP) is investigated in primates during and after -6-deg head-down tilt (HDT) and immersion in water to examine the effects of the headward fluid shift related to spaceflight. Following the HDT the primates are subjected to head-out thermoneutral water immersion, and the ICP is subsequently measured. ICP is found to increase from 3.8 +/- 1.1 to 5.3 +/- 1.3 mm Hg during the horizontal control period. ICP stabilizes at -6.3 +/- 1.3 mm Hg and then increases to -2.2 +/- 1.9 mm Hg during partial immersion, and ICP subsequently returns to preimmersion levels after immersion. These data indicate that exposure to HDT or water immersion lead to an early sharp increase in ICP, and water immersion alone leads to higher ICP levels. A significant conclusion of the work is that the ICP did not approach pathological levels, and this finding is relevant to human spaceflight research.

  6. Orthostatic intolerance in 6 degrees head-down tilt and lower body negative pressure loading

    Science.gov (United States)

    Yajima, Kazuyoshi; Miyamoto, Akira; Ito, Masao; Mano, Takaichi; Nakayama, Kiyoshi

    6 degrees head-down tilt bed rest experiment for 6 days was conducted at Nihon University Itabashi Hospital for 10 male athletes. In order to observe the orthostatic intolerance due to six days head-down tilt bed rest, 70 degrees head up tilt tests were performed before and after the head-down tilt. Two types of orthostatic intolerance were distinguished by the time course of their cardiovascular responses. One was vagotonia type and the other was brain anemia type. The latter type was commonly seen among astronauts after space flight due to the lack of plasma volume. As this volume change is considered to be initiated by some fluid loss from the lower extremities, analysis was made to clarify the relation between the leg volume change and the types of orthostatic intolerance. Nakayama proposed a Heart Rate Controllability Index, which is calculated from the initiate leg volume change and heart rate increase in head up tilt, for an indicator of the orthostatic intolerability. The index was applied to the subjects of six days head-down tilt above mentioned. For the subjects who showed a sign of presyncopy, the index values were higher or lower than that of the rest subjects who showed no sign of presyncopy. In order to evaluate the validity of the index, another experiment was conducted to induce an orthostatic intolerance by a different way of loading. The same types of orthostatic intolerance were observed and the index value hit high in the brain anemia type of orthostatic intolerance, while the vagotonia type showed relatively lower values than the normal group.

  7. Head-Down Tilt with Balanced Traction as a Model for Simulating Spinal Acclimation to Microgravity

    Science.gov (United States)

    Ballard, R. E.; Styf, J. R.; Watenpaugh, D. E.; Fechner, K.; Haruna, Y.; Kahan, N. J.; Hargens, A. R.

    1994-01-01

    Astronauts experience total body height increases of 4 to 7 cm in microgravity. Thus, stretching of the spinal cord, nerve roots, and muscular and ligamentous tissues may be responsible for the hyperreflexia, back pain, and muscular atrophy associated with exposure to microgravity. Axial compression of the spine makes 6 deg. head-down tilt (HDT) an unsuitable model for spinal acclimation to microgravity. However, this axial compression may be counteracted by balanced traction consisting of 10% body weight (sin 6 deg. = 0.1) applied to the legs. Six healthy male subjects underwent 3 days each of 60 HDT with balanced traction and horizontal bed rest (HBR), with a 2 week recovery period between treatments. Total body and spine length, lumbar disc height, back pain, erector spinae intramuscular pressure, and ankle joint torque were measured before, during and after each treatment. Total body and spine (processes of L5 - C7) lengths increased significantly more during HDT with balanced traction (22 +/- 8 mm and 25 +/- 8 mm, respectively) than during HBR (16 +/- 4 mm and 14 +/- 9 mm, respectively). Back and leg pain were significantly greater during HDT with balanced traction than during HBR. The distance between the lower end plate of L4 and the upper endplate of S1, as measured by sonography, increased significantly in both treatments to the same degree (2.9 +/- 1.9 mm, HDT with balanced traction; 3.3 +/- 1.5 mm, HBR). Intramuscular pressure of the erector spinae muscles and maximal ankle joint torque were unaltered with both models. While neither model increased height to the magnitude observed in microgravity, HDT with balanced traction may be a better model for simulating the body lengthening and back pain experienced in microgravity.

  8. Effects of 1-week head-down tilt bed rest on bone formation and the calcium endocrine system

    Science.gov (United States)

    Arnaud, Sara B.; Whalen, Robert T.; Fung, Paul; Sherrard, Donald J.; Maloney, Norma

    1992-01-01

    The -6-deg head-down tilt (HDT) is employed in the study of 8 subjects to determine early responses in human bone and calcium endocrines during spaceflight. The average rates of bone formation in the iliac crest are determined by means of a single-dose labeling schedule and are found to decrease in 6 of the subjects. The decrease varies directly with walking miles, and increased excretion of urinary Ca and Na are observed preceding increased levels of ionized serum calcium on a bed-rest day late in the week. Reduced phosphorous excretions are also followed by increased serum phosphorous on day six, and reductions are noted in parathyroid hormone and vitamin D by the end of the experiment. The data demonstrate the responsiveness of the skeletal system to biomechanical stimuli such as the HDT.

  9. Exercise thermoregulation in men after 1 and 24-hours of 6 degrees head-down tilt

    Science.gov (United States)

    Ertl, A. C.; Dearborn, A. S.; Weidhofer, A. R.; Bernauer, E. M.; Greenleaf, J. E.

    2000-01-01

    BACKGROUND: Exercise thermoregulation is dependent on heat loss by increased skin blood flow (convective and conductive heat loss) and through enhanced sweating (evaporative heat loss). Reduction of plasma volume (PV), increased plasma osmolality, physical deconditioning, and duration of exposure to simulated and actual microgravity reduces the ability to thermoregulate during exercise. HYPOTHESIS: We hypothesized that 24 h of head down tilt (HDT24) would alter thermoregulatory responses to a submaximal exercise test and result in a higher exercise rectal temperature (Tre) when compared with exercise Tre after 1 h of head down tilt (HDT1). METHODS: Seven men (31+/-SD 6 yr, peak oxygen uptake (VpO2peak) of 44+/-6 ml x kg(-1) x min(-1)) were studied during 70 min of supine cycling at 58+/-SE 1.5% VO2peak at 22.0 degrees C Tdb and 47% rh. RESULTS: Relative to pre-tilt sitting chair rest data, HDT1 resulted in a 6.1+/-0.9% increase and HDT24 in a 4.3+/-2.3% decrease in PV (delta = 10.4% between experiments, pthermoregulation), the Tre offset could have been caused by the HDT-induced hypovolemia.

  10. Analysis of Arterial Mechanics During Head-down Tilt Bed Rest

    Science.gov (United States)

    Elliot, Morgan; Martin, David S.; Westby, Christian M.; Stenger, Michael B.; Platts, Steve

    2014-01-01

    Arterial health may be affected by microgravity or ground based analogs of spaceflight, as shown by an increase in thoracic aorta stiffness1. Head-down tilt bed rest (HDTBR) is often used as a ground-based simulation of spaceflight because it induces physiological changes similar to those that occur in space2, 3. This abstract details an analysis of arterial stiffness (a subclinical measure of atherosclerosis), the distensibility coefficient (DC), and the pressure-strain elastic modulus (PSE) of the arterial walls during HDTBR. This project may help determine how spaceflight differentially affects arterial function in the upper vs. lower body.

  11. Male reproductive system in conditions of bed-rest in a head-down tilt.

    Science.gov (United States)

    Nichiporuk, I A; Evdokimov, V V; Erasova, V I; Smirnov, O A; Goncharova, A G; Vassilieva GYu; Vorobiev, D V

    1998-07-01

    Study of reproductive function in simulating experiments is important as for expansion of our theoretical knowledge in the field of gravitational physiology and space biology and for the decision of applied problems in space and clinical medicine. Long-term bed rest in a head-down tilt--6 degrees (BRHDT)--antiorthostatic hypokinesia is a wide spread method for ground-based simulation of space flight's conditions (mainly of hemodynamical effects of microgravity and restriction of locomotor activity). The aim of the present research was to study a reproductive function in males during 60-120 day BRHDT.

  12. [Evaluation of synthetic antidiuretic hormone as a corrective substance following head-down tilt].

    Science.gov (United States)

    Noskov, V B; Larina, I M; Nichiporuk, I A; Pastushkova, L Kh; Vasil'eva, G Iu

    2010-01-01

    Effects of synthesized desmopressin, analog of antidiuretic hormone, and water-salt supplement on the renal function and orthostatic stability were studied in 6 normal male subjects after 12-hr. head-down tilt (12 degrees). The combination of water-salt homeostasis normalizing methods was effective in retaining excessive liquid and salts. Moreover, tolerance of the standard 20-min. passive standing test improved significantly. Hence, it was demonstrated that intake of synthetic vasopressin analog combined with WSS counteracted hypohydration of organism due to HDT and improved orthostatic tolerance.

  13. Volume loading of the heart by "leg up" position and head down tilting (-6°) (HDT)

    Science.gov (United States)

    Dirschedl, P.; Gregull, A.; Löllgen, H.

    Head down tilting is widely used to increase preload and to induce intrathoracic blood pooling similar to microgravity. During daily routine, this venous pooling is performed by rising the legs up. In this study, both these approaches have been compared by invasive measurement using a right heart catheter. In patients with moderate coronary artery disease, diagnostic right heart catheterization was performed by the Swan-Ganz-techniques. All measurements were performed with head down tilting (-6°) and with "leg up" position. Patients then received Nitrogycerin to countermeasure the preload changes. Pressures in the pulmonary artery as well as in the wedge position increased significantly during leg up and HDT. However, changes were significantly more pronouced in the "leg up" position than during HDT. No changes were observed for arterial blood pressure, cardiac output, stroke volume and resistances. Nitroglycerin during HDT lowered blood pressure and pressures in the pulmonary artery and in PCW-position and reduced cardiac output significantly. Both approaches of volume loading of the heart induced significant changes and increases of preload. However, changes were more pronounced during the "leg up" position than during HDT. It is questioned whether HDT with -6° is appropriate to truly reflect hemodynamic alterations during simulated weightlessness.

  14. Alterations in Skeletal Muscle Microcirculation of Head-Down Tilted Rats

    Science.gov (United States)

    Musacchia, X. J.; Stepke, Bernhard; Fleming, John T.; Joshua, Irving G.

    1992-01-01

    In this study we assessed the function of microscopic blood vessels in skeletal muscle (cremaster muscle) for alterations which may contribute to the observed elevation of blood pressure associated with head-down tilted whole body suspension (HDT/WBS), a model of weightlessness. Arteriolar baseline diameters, vasoconstrictor responses to norepinephrine (NE) and vasodilation to nitroprusside (NP) were assessed in control rats, rats suspended for 7 or 14 day HDT/WBS rats, and rats allowed to recover for 1 day after 7 days HDT/WBS. Neither baseline diameters nor ability to dilate were influenced by HDT/WBS. Maximum vasoconstriction to norepinephrine was significantly greater in arterioles of hypertensive 14 day HDT/WBS rats. This first study of the intact microvasculature in skeletal muscle indicates that an elevated contractility of arterioles to norepinephrine in suspended rats, and suggests an elevated peripheral resistance in striated muscle may contribute to the increase in blood pressures among animals subjected to HDT/WBS.

  15. Intracranial and Intraocular Pressure During Various Degrees of Head-Down Tilt.

    Science.gov (United States)

    Marshall-Goebel, Karina; Mulder, Edwin; Bershad, Eric; Laing, Charles; Eklund, Anders; Malm, Jan; Stern, Claudia; Rittweger, Jörn

    2017-01-01

    More than half of astronauts develop ophthalmic changes during long-duration spaceflight consistent with an abnormal intraocular and intracranial pressure (IOP, ICP) difference. The aim of our study was to assess IOP and ICP during head-down tilt (HDT) and the additive or attenuating effects of 1% CO2 and lower body negative pressure (LBNP). In Experiment I, IOP and ICP were measured in nine healthy subjects after 3.5 h HDT in five conditions: -6°, -12°, and -18° HDT, -12° with 1% CO2, and -12° with -20 mmHg LBNP. In Experiment II, IOP was measured in 16 healthy subjects after 5 min tilt at +12°, 0°, -6°, -12°, -18°, and -24°, with and without -40 mmHg LBNP. ICP was only found to increase from supine baseline during -18° HDT (9.2 ± 0.9 and 14.4 ± 1 mmHg, respectively), whereas IOP increased from 15.7 ± 0.3 mmHg at 0° to 17.9 ± 0.4 mmHg during -12° HDT and from 15.3 ± 0.4 mmHg at 0° to 18.7 ± 0.4 mmHg during -18° HDT. The addition of -20 mmHg LBNP or 1% CO2 had no further effects on ICP or IOP. However, the use of -40 mmHg LBNP during HDT lowered IOP back to baseline values, except at -24° HDT. A small, posterior intraocular-intracranial pressure difference (IOP > ICP) is maintained during HDT, and a sustained or further decreased difference may lead to structural changes in the eye in real and simulated microgravity.Marshall-Goebel K, Mulder E, Bershad E, Laing C, Eklund A, Malm J, Stern C, Rittweger J. Intracranial and intraocular pressure during various degrees of head-down tilt. Aerosp Med Hum Perform. 2017; 88(1):10-16.

  16. Back pain during 6 degrees head-down tilt approximates that during actual microgravity

    Science.gov (United States)

    Hutchinson, K. J.; Watenpaugh, D. E.; Murthy, G.; Convertino, V. A.; Hargens, A. R.

    1995-01-01

    Astronauts often experience back pain during spaceflight. Retrospectively, Wing et al. (14) found that during spaceflight, 14 of 19 Shuttle crewmembers experienced back pain, which they described as dull (62%), localized to the lower back (50%), and with an intensity of 2 on a 5-point scale. Further, the spine lengthens 4-7 cm in microgravity. Our objective was to compare back pain and spinal lengthening (body height increase) during simulated microgravity (6 degrees head-down tilt, HDT) with the same parameters during actual microgravity. Eight male subjects completed a modified McGill pain questionnaire with intensity graded from zero (no pain) to five (intense and incapacitating pain) each day at 7:00 pm during 2 d pre-HDT control, 16 d HDT, and 1 d post-HDT recovery periods. Also, the subjects' heights were measured each day while supine (control and recovery) and during HDT. Back pain increased from zero (pre-tilt control period) to 2.3 +/- 0.4 at days 1 to 3 of HDT, and was categorized as dull and/or burning pain in subjects' lower backs. Only 2 subjects reported any pain after day 9 of HDT and during recovery. Heights increased 2.1 +/- 0.5 cm by day 3 of HDT and remained at that level until the end of the HDT period. Although spinal lengthening in space is greater than that during HDT, the HDT model approximates the level, type, distribution, and time course of back pain associated with actual microgravity. In the HDT model, pain subsides in intensity when spinal lengthening stops.(ABSTRACT TRUNCATED AT 250 WORDS).

  17. Cerebral haemodynamic response to acute intracranial hypertension induced by head-down tilt.

    Science.gov (United States)

    Bosone, Daniele; Ozturk, Vesile; Roatta, Silvestro; Cavallini, Anna; Tosi, Piera; Micieli, Giuseppe

    2004-01-01

    The aim of this study was to evaluate, in a context of general inhibition of the sympathetic nervous system, the cerebral haemodynamic response to -30 degrees head-down tilt (HDT), a manoeuvre that produces an increase in intracranial arterial pressure. Nineteen healthy subjects were studied according to the following protocol: 10 min lying in supine position, 10 min HDT, 10 min recovery. Inhibition of the sympathetic system was confirmed by the decrease in heart rate (-3.6 bpm) and arterial blood pressure (-5.9 mmHg, p<0.05) in the late phase of the test. Blood velocity and blood pusatility index initially increased (+3.2 cm s(-1) and +9% respectively, p<0.01) then returned towards baseline before the end of HDT, while the cerebrovascular resistance index (=arterial blood pressure/blood velocity) dropped significantly and remained below control level (-7%, p<0.01) throughout the test. The changes in both these indices were opposite to those reported in several sympathetic activation tests, such as the handgrip and cold pressor tests. Conversely, arterial pressure at cranial level increased during HDT (as it also does during sympathetic activation tests), due to the development of a hydrostatic pressure gradient between heart and brain levels. Therefore, the effects observed on the pulsatility and resistance indices are not secondary to the increase in intracranial arterial pressure. It is suggested that the changes in these cerebrovascular indices are mediated by a reduction of sympathetic tone that presumably involves the cerebral as well as the peripheral vascular bed.

  18. The Effects of Spaceflight and Head Down Tilt Bed Rest on Neurocognitive Performance: Extent, Longevity, and Neural Bases

    Science.gov (United States)

    Seidler, Rachael D.; Bloomberg, Jacob; Wood, Scott; Mulavara, Ajit; Kofman, Igor; De Dios, Yiri; Gadd, Nicole; Stepanyan, Vahagn

    2017-01-01

    Spaceflight effects on gait, balance, & manual motor control have been well studied; some evidence for cognitive deficits. Rodent cortical motor & sensory systems show neural structural alterations with spaceflight. specific Aims: Aim 1-Identify changes in brain structure, function, and network integrity as a function of head down tilt bed rest and spaceflight, and characterize their time course. Aim 2-Specify relationships between structural and functional brain changes and performance and characterize their time course.

  19. Effects of Head-down Tilt on Nerve Conduction in Rhesus Monkeys

    Science.gov (United States)

    Sun, Bo; Zhang, Xiao-Yun; Liu, Li-Zhi; Chen, Zhao-Hui; Dai, Zhong-Quan; Huang, Xu-Sheng

    2017-01-01

    Background: Few studies have focused on peripheral nerve conduction during exposure to microgravity. The −6° head-down tilt (HDT) comprises an experimental model used to simulate the space flight environment. This study investigated nerve conduction characteristics of rhesus monkeys before and after prolonged exposure to HDT. Methods: Six rhesus monkeys (3–4 years old) were tilted backward 6° from the horizontal. Nerve conduction studies (NCSs) were performed on the median, ulnar, tibial, and fibular motor nerves. Analysis of variance with a randomized block design was conducted to compare the differences in the NCS before and 7, 21, and 42 days after the −6° HDT. Results: The proximal amplitude of the CMAP of the median nerve was significantly decreased at 21 and 42 days of HDT compared with the amplitude before HDT (4.38 ± 2.83 vs. 8.40 ± 2.66 mV, F = 4.85, P = 0.013 and 3.30 ± 2.70 vs. 8.40 ± 2.66 mV, F = 5.93, P = 0.004, respectively). The distal amplitude of the CMAP of the median nerve was significantly decreased at 7, 21, and 42 days of HDT compared with the amplitude before HDT (7.28 ± 1.27 vs. 10.25 ± 3.40 mV, F = 4.03, P = 0.039; 5.05 ± 2.01 vs. 10.25 ± 3.40 mV, F = 6.25, P = 0.04; and 3.95 ± 2.79 vs. 10.25 ± 3.40 mV, F = 7.35, P = 0.01; respectively). The proximal amplitude of the CMAP of the tibial nerve was significantly decreased at 42 days of HDT compared with the amplitude before HDT (6.14 ± 1.94 vs. 11.87 ± 3.19 mV, F = 5.02, P = 0.039). Conclusions: This study demonstrates that the compound muscle action potential amplitudes of nerves are decreased under simulated microgravity in rhesus monkeys. Moreover, rhesus monkeys exposed to HDT might be served as an experimental model for the study of NCS under microgravity. PMID:28139516

  20. Focal Gray Matter Plasticity as a Function of Long Duration Head-down Tilt Bed Rest

    Science.gov (United States)

    Koppelmans, V.; DeDios, Y. E.; Wood, S. J.; Reuter-Lorenz, P. A.; Kofman, I.; Bloomberg, J. J.; Mulavara, A. P.; Koppelmans, V.

    2014-01-01

    Long duration spaceflight (i.e., > or = 22 days) has been associated with changes in sensorimotor systems, resulting in difficulties that astronauts experience with posture control, locomotion, and manual control. The microgravity environment is an important causal factor for spaceflight induced sensorimotor changes. Whether these sensorimotor changes may be related to structural and functional brain changes is yet unknown. However, experimental studies revealed changes in the gray matter (GM) of the brain after simulated microgravity. Thus, it is possible that spaceflight may affect brain structure and thereby cognitive functioning and motor behavior. Long duration head-down tilt bed rest has been suggested as an exclusionary analog to study microgravity effects on the sensorimotor system. Bed rest mimics microgravity in body unloading and bodily fluid shifts. In consideration of the health and performance of crewmembers both in- and post-flight, we are conducting a prospective longitudinal 70-day bed rest study as an analog to investigate the effects of microgravity on the brain. VBM analysis revealed a progressive decrease from pre- to in- bed rest in GM volume in bilateral areas including the frontal medial cortex, the insular cortex and the caudate. Over the same time period, there was a progressive increase in GM volume in the cerebellum, occipital-, and parietal cortex, including the precuneus. The majority of these changes did not fully recover during the post-bed rest period. Analysis of lobular GM volumes obtained with BRAINS showed significantly increased volume from pre-bed rest to in-bed rest in GM of the parietal lobe and the third ventricle. Temporal GM volume at 70 days in bed rest was smaller than that at the first pre-bed rest measurement. Trend analysis showed significant positive linear and negative quadratic relationships between parietal GM and time, a positive linear relationship between third ventricle volume and time, and a negative linear

  1. Analysis by NASA's VESGEN Software of Retinal Blood Vessels in Human Subjects Undergoing Head-Down Tilt During 70-Day Bed Rest

    Science.gov (United States)

    Vyas, Ruchi J.; Murray, Matthew C.; Predovic, Marina; Lim, Shiyin; Askin, Kayleigh N.; Vizzeri, Gianmarco; Taibbi, Giovanni; Mason, Sara Stroble; Zanello, Susana B.; Young, Millenia; hide

    2017-01-01

    Significant risks for visual impairment associated with increased intracranial pressure (VIIP) are incurred by microgravity spaceflight, especially long-duration missions [1]. We hypothesize that microgravity-induced fluid shifts result in pathological changes within blood vessels of the retina that precede development of visual and other ocular impairments. Potential contributions of retinal vascular remodeling to VIIP etiology are therefore being investigated for two studies in 30deg infrared (IR) Heidelberg Spectralis(Registered Trademark) images with NASA's innovative VESsel GENeration Analysis (VESGEN) software [2,3]. The retrospective studies include: (1) before, during and after (pre, mid and post) 6º head-down tilt (HDT) in human subjects during 70 days of bed rest, and (2) before and after missions to the International Space Station (ISS) by U.S. crew members. Results for both studies are almost complete. A preliminary example for HDT is described below.

  2. [Desmopressin effect on water-salt homeostasis and orthostatic tolerance during head-down tilting].

    Science.gov (United States)

    Larina, I M; Noskov, V B; Nichiporuk, I A; Pastushkova, L Kh; Vasil'eva, G Iu

    2009-01-01

    Effects of desmopressin, a synthetic analog of antidiuretic hormone (ADH), on water-salt metabolism and orthostatic tolerance were evaluated in human subjects during 24-hr HDT (-15 degrees). Consumption of the preparation was found to dampen losses in total body and extracellular liquids and to slow down diuresis as well as establishment of a positive water balance as compared with control series without ADH. In addition, tolerance of the standard standing test improved noticeably. To conclude, desmopressin precluded hypohydration of the tilted subjects and, consequently, prevented loss of orthostatic tolerance.

  3. Gender differences in endocrine responses to posture and 7 days of 6 deg head down bed rest

    Science.gov (United States)

    Vernikos, J.; Dallman, M. F.; Keil, L. C.; Ohara, D.; Convertino, V. A.

    1993-01-01

    Endocrine regulation of fluids and electrolytes during seven days of 6 deg head down bed rest (HDBR) was compared in male (n = 8) and, for the first time, female (n = 8) volunteers. The subjects' responses to quiet standing for 2 hr before and after HDBR were also tested. In both sexes, diuresis and natriuresis were evident during the first 2-3 days of HDBR, resulting in a marked increase in the urinary Na/K ratio and significant Na retention on reambulation. After the first day of HDBR, plasma renin activity (PRA) was increased relative to aldosterone, plasma volume was decreased, and the renal response to aldosterone appeared to be appropriate. Circulating levels of arginine vasopressin (AVP), cortisol, and ACTH were unchanged during HDBR. Plasma testosterone decreased slightly on day 2 of HDBR in males. The ratio of AM ACTH to cortisol was lower in females than in males because ACTH was lower in females. Urinary cortisol increased and remained elevated throughout the HDBR in males only. There were no gender differences in the responses to 7 day HDBR, except those in the pituitary-adrenal system; those differences appeared unrelated to the postural change. The provocative cardiovascular test of quiet standing before and after bed rest revealed both sex differences and effects of HDBR. There were significant sex differences in cardiovascular responses to standing, before and after HDBR. Females had greater PRA and aldosterone responses to standing before bedrest and larger aldosterone responses to standing after HDBR than males. Cardiovascular responses to standing before and after bedrest differed markedly: arterial pressure and heart rates increased with standing before HDBR, by contrast, arterial pressure decreased, with greater increases in heart rates after HDBR. In both sexes, all hormonal responses to standing were greater after HDBR. The results show clearly that similar responses to standing as well as to HDBR occur in both sexes, but that females exhibit

  4. Increased Brain Activation for Foot Movement During 70-Day 6 Deg Head-Down Bed Rest (HDBR): Evidence from Functional Magnetic Resonance Imaging (fMRI)

    Science.gov (United States)

    Yuan, P.; Koppelmans, V.; Cassady, K.; Cooke, K.; De Dios, Y. E.; Stepanyan, V.; Szecsy, D.; Gadd, N.; Wood, S. J.; Reuter-Lorenz, P. A.; hide

    2015-01-01

    Bed rest has been widely used as a simulation of weightlessness in studying the effects of microgravity exposure on human physiology and cognition. Changes in muscle function and functional mobility have been reported to be associated with bed rest. Understanding the effect of bed rest on neural control of movement would provide helpful information for spaceflight. In the current study, we evaluated how the brain activation for foot movement changed as a function of bed rest. Eighteen healthy men (aged 25 to 39 years) participated in this HDBR study. They remained continuously in the 6deg head-down tilt position for 70 days. Functional MRI was acquired during 1-Hz right foot tapping, and repeated at 7 time points: 12 days pre-, 8 days pre-, 7 days in-, 50 days in-, 70 days in-, 8 days post-, and 12 days post- HDBR. In all 7 sessions, we observed increased activation in the left motor cortex, right cerebellum and right occipital cortex during foot movement blocks compared to rest. Compared to the pre-HDBR baseline (1st and 2nd sessions), foot movement-induced activation in the left hippocampus increased during HDBR. This increase emerged in the 4th session, enlarged in the 5th session, and remained significant in the 6th and 7th sessions. Furthermore, increased activation relative to the baseline in left precuneus was observed in the 5th, 6th and 7th sessions. In addition, in comparison with baseline, increased activation in the left cerebellum was found in the 4th and 5th sessions, whereas increased activation in the right cerebellum was observed in the 4th, 6th and 7th sessions. No brain region exhibited decreased activation during bed rest compared to baseline. The increase of foot movement related brain activation during HDBR suggests that in a long-term head-down position, more neural control is needed to accomplish foot movements. This change required a couple of weeks to develop in HDBR (between 3rd and 4th sessions), and did not return to baseline even 12

  5. Effects of Resistive Vibration Exercise Combined with Whey Protein and KHCO3 on Bone Tturnover Markers in Head-down Tilt Bed Rest (MTBR-MNX Study)

    Science.gov (United States)

    Graf, Sonja; Baecker, Natalie; Buehlmeier, Judith; Fischer, Annelie; Smith, Scott M.; Heer, Martina

    2014-01-01

    High protein intake further increases bone resorption markers in head-down tilt bed rest (HDBR), most likely induced by low-grade metabolic acidosis. Adding an alkaline salt to a diet with high protein content prevents this additional rise of bone resorption markers in HDBR. In addition, high protein intake, specifically whey protein, increases muscle protein synthesis and improves glucose tolerance, which both are affected by HDBR. Resistive vibration exercise (RVE) training counteracts the inactivity-induced bone resorption during HDBR. To test the hypothesis that WP plus alkaline salt (KHCO3) together with RVE during HDBR will improve bone turnover markers, we conducted a randomized, three-campaign crossover design study with 12 healthy, moderately fit male subjects (age 34+/-8 y, body mass [BM] 70 +/- 8 kg). All study campaigns consisted of a 7-d ambulatory period, 21days of -6 deg. head-down tilt bed rest (HDBR), and a 6-d recovery period. Diet was standardized and identical across phases. In the control (CON) campaign, subjects received no supplement or RVE. In the intervention campaigns, subjects received either RVE alone or combined with WP and KHCO3 (NEX). WP was applied in 3 doses per day of 0.6 g WP/kg BM together with 6 doses of 15 mmol KHCO3 per day. Eleven subjects completed the RVE and CON campaign, 8 subjects completed all three campaigns. On day 21 of HDBR excretion of the bone resorption marker C-telopeptide (CTX) was 80+/-28% (p<0.001) higher than baseline, serum calcium concentrations increased by 12 +/- 29% (p<0.001) and serum osteocalcin concentrations decreased by 6+/-12% (p=0.001). Urinary CTX excretion was 11+/- 25% (p=0.02) lower on day 21 of HDBR in the RVE- and tended to decrease by 3+/- 22% (p=0.06) in the NEX campaign compared to CON. Urinary calcium excretion was higher on day 21 in HDBR in the RVE and NEX (24+/- 43% p=0.01; 25+/- 37% p=0.03) compared to the CON campaign. We conclude that combination of RVE with WP/KHCO3 was not

  6. Intracranial blood flow measured with single photon emission computer tomography (SPECT) during transient -6 degrees head-down tilt.

    Science.gov (United States)

    Satake, H; Konishi, T; Kawashima, T; Matsunami, K; Uno, T; Imai, S; Yamada, H; Hirakawa, C

    1994-02-01

    Regional cerebral blood flow (CBF) during a transient head-down tilt of -6 degrees (-6 degrees HDT) was measured with single photon emission computer tomography (SPECT). CBF was measured and averaged for both sides of the brain areas; e.g., the bilateral anterior cerebral artery (bACA) area, the middle cerebral artery (bMCA) area, the posterior cerebral artery (bPCA) area, bilateral basal ganglia, and the cerebellum. Among these areas, a significant increase in CBF was observed in the basal ganglia and the cerebellum during -6 degrees HDT compared to pre-HDT. When CBF was measured separately in the left or right brain area, these significances disappeared, although a trend of increase or decrease was still observable. A trend of increase was observed in the left anterior cerebral artery (IACA) area, the right middle cerebral artery (rMCA) area, the right posterior cerebral artery (rPCA) area, the left and right basal ganglia, and the cerebellum. In rACA, IMCA and IPCA areas, a slight decrease in CBF was observed. At the same time, cardiac parameters were measured. Heart rate (HR), stroke volume (SV) and cardiac output (CO) did not change significantly, although SV slightly increased and HR slightly decreased during -6 degrees HDT.

  7. Psychomotor performance during a 28 day head-down tilt with and without lower body negative pressure

    Science.gov (United States)

    Traon, A. Pavy-le; de Feneyrols, A. Rous; Cornac, A.; Abdeseelam, R.; N'uygen, D.; Lazerges, M.; Güell, A.; Bes, A.

    Several factors may affect psychomotor performance in space: sensory-motor changes, sleep disturbances, psychological modifications induced by the social isolation and confinement. However, psychomotor performance is difficult to assess. A battery of standardized and computerized tests, so-called "Automated Portable Test System" (APTS) was devised to ascertain the cognitive, perceptive and motor abilities and their possible fluctuations according to environmental effects. Antiorthostatic bedrest, often used to simulate weightlessness, (particularly cardiovascular modifications) also constitutes a situation of social confinement and isolation. During two bedrest experiments (with head-down tilt of -6°) of 28 days each, we intended to assess psychomotor performance of 6 males so as to determine whether: —on the one hand, it could be altered by remaining in decubitus; —on the other, the Lower Body Negative Pressure sessions, designed to prevent orthostatic intolerance back on Earth, could improve the performance. To accomplish this, part of the APTS tests as well as an automated perceptive attention test were performed. No downgrading of psychomotor performance was observed. On the contrary, the tasks were more accurately performed over time. In order to assess the experimental conditions on the acquisition phase, the learning curves were modelled. A beneficial effect of the LBNP sessions on simple tests involving the visual-motor coordination and attention faculties can only be regarded as a mere trend. Methods used in this experiment are also discussed.

  8. Interpersonal relationships in isolation and confinement: Long-term bed rest in head-down tilt position

    Science.gov (United States)

    Karine, Weiss; Gabriel, Moser

    The long-term bed-rest was organized by ESA and CNES, in order to simulate the physiological effects of weightlessness: eight volunteers had to stay 42 days in bed, in a head down tilt position (-6 °). There were two subjects in a room, they could not be alone and it was difficult for them to have their own personal space and intimacy. In these circumstances, as in outer space, interpersonal relationships were of prime importance. This situation enabled us, through systematic observation, to analyze the evolution of the relational behavior in dyads, and to quote some social indicators of adaptation. Results show significant withdrawal, and the time spent alone was marked by the emergence, during the experiment, of specific preferential activities. Behavioral contagion was observed in each dyad (people engaged in the same activities at the same time), except in the one case of abandon. Moreover, the highest rates of inactivity and withdrawal were noted in this case. Verbal indicators were useful to comment these results and showed that, for all the dyads, one of the two subjects always played a regulating role by expressing a very positive perception of the situation. These results emphasize the importance of psycho-sociological factors in isolation and confinement. Thus, it appears that different modalities of interpersonal relationships, and not only verbal interactions, play a significant role in adaptation to stress situations.

  9. Effect of head-down-tilt bed rest and hypovolemia on dynamic regulation of heart rate and blood pressure

    Science.gov (United States)

    Iwasaki, K. I.; Zhang, R.; Zuckerman, J. H.; Pawelczyk, J. A.; Levine, B. D.; Blomqvist, C. G. (Principal Investigator)

    2000-01-01

    Adaptation to head-down-tilt bed rest leads to an apparent abnormality of baroreflex regulation of cardiac period. We hypothesized that this "deconditioning response" could primarily be a result of hypovolemia, rather than a unique adaptation of the autonomic nervous system to bed rest. To test this hypothesis, nine healthy subjects underwent 2 wk of -6 degrees head-down bed rest. One year later, five of these same subjects underwent acute hypovolemia with furosemide to produce the same reductions in plasma volume observed after bed rest. We took advantage of power spectral and transfer function analysis to examine the dynamic relationship between blood pressure (BP) and R-R interval. We found that 1) there were no significant differences between these two interventions with respect to changes in numerous cardiovascular indices, including cardiac filling pressures, arterial pressure, cardiac output, or stroke volume; 2) normalized high-frequency (0.15-0.25 Hz) power of R-R interval variability decreased significantly after both conditions, consistent with similar degrees of vagal withdrawal; 3) transfer function gain (BP to R-R interval), used as an index of arterial-cardiac baroreflex sensitivity, decreased significantly to a similar extent after both conditions in the high-frequency range; the gain also decreased similarly when expressed as BP to heart rate x stroke volume, which provides an index of the ability of the baroreflex to alter BP by modifying systemic flow; and 4) however, the low-frequency (0.05-0.15 Hz) power of systolic BP variability decreased after bed rest (-22%) compared with an increase (+155%) after acute hypovolemia, suggesting a differential response for the regulation of vascular resistance (interaction, P < 0.05). The similarity of changes in the reflex control of the circulation under both conditions is consistent with the hypothesis that reductions in plasma volume may be largely responsible for the observed changes in cardiac

  10. The Effects of Long Duration Head Down Tilt Bed Rest on Neurocognitive Performance: The Effects of Exercise Interventions

    Science.gov (United States)

    Seidler, R. D.; Mulavara, A. P.; Koppelmans, V.; Erdeniz. B.; Kofman, I. S.; DeDios, Y. E.; Szecsy, D. L.; Riascos-Castaneda, R. F.; Wood, S. J.; Bloomberg, J. J.

    2014-01-01

    We are conducting ongoing experiments in which we are performing structural and functional magnetic resonance brain imaging to identify the relationships between changes in neurocognitive function and neural structural alterations following a six month International Space Station mission and following 70 days exposure to a spaceflight analog, head down tilt bedrest. Our central hypothesis is that measures of brain structure, function, and network integrity will change from pre to post intervention (spaceflight, bedrest). Moreover, we predict that these changes will correlate with indices of cognitive, sensory, and motor function in a neuroanatomically selective fashion. Our interdisciplinary approach utilizes cutting edge neuroimaging techniques and a broad ranging battery of sensory, motor, and cognitive assessments that will be conducted pre flight, during flight, and post flight to investigate potential neuroplastic and maladaptive brain changes in crewmembers following long-duration spaceflight. Success in this endeavor would 1) result in identification of the underlying neural mechanisms and operational risks of spaceflight-induced changes in behavior, and 2) identify whether a return to normative behavioral function following re-adaptation to Earth's gravitational environment is associated with a restitution of brain structure and function or instead is supported by substitution with compensatory brain processes. Our ongoing bed rest participants are also engaging in exercise studies directed by Dr. Lori Ploutz Snyder. In this presentation, I will briefly highlight the existing literature linking exercise and fitness to brain and behavioral functions. I will also overview the metrics from my study that could be investigated in relation to the exercise and control subgroups.

  11. Six-Degree Head-Down Tilt Bed Rest: Forty Years of Development as a Physiological Analog for Weightlessness

    Science.gov (United States)

    Smith, Jeffrey D.; Cromwell, Ronita L.; Kundrot, Craig E.; Charles, John B.

    2011-01-01

    Early on, bed rest was recognized as a method for inducing many of the physiological changes experienced by spaceflight. Head-down tilt (HDT) bed rest was first introduced as an analog for spaceflight by a Soviet team led by Genin and Kakurin. Their study was performed in 1970 (at -4 degrees) and lasted for 30 days; results were reported in the Russian Journal of Space Biology (Kosmicheskaya Biol. 1972; 6(4): 26-28 & 45-109). The goal was to test physiological countermeasures for cosmonauts who would soon begin month-long missions to the Salyut space station. HDT was chosen to produce a similar sensation of blood flow to the head reported by Soyuz cosmonauts. Over the next decade, other tilt angles were studied and comparisons with spaceflight were made, showing that HDT greater than 4 degrees was superior to horizontal bed rest for modeling acute physiological changes observed in space; but, at higher angles, subjects experienced greater discomfort without clearly improving the physiological comparison to spaceflight. A joint study performed by US and Soviet investigators, in 1979, set the goal of standardization of baseline conditions and chose 6-degrees HDT. This effectively established 6-degree HDT bed rest as the internationally-preferred analog for weightlessness and, since 1990, nearly all further studies have been conducted at 6-degrees HDT. A thorough literature review (1970-2010) revealed 534 primary scientific journal articles which reported results from using HDT as a physiological analog for spaceflight. These studies have ranged from as little as 10 minutes to the longest duration of 370 days. Long-term studies lasting four weeks or more have resulted in over 170 primary research articles. Today, the 6-degree HDT model provides a consistent, thoroughly-tested, ground-based analog for spaceflight and allows the proper scientific controls for rigorous testing of physiological countermeasures; however, all models have their strengths and limits. The 6

  12. Long Duration Head Down Tilt Bed Rest and Spaceflight Effects on Neurocognitive Performance: Extent, Longevity and Neural Bases

    Science.gov (United States)

    Seidler, R. D.; Mulavara, A. P.; Koppelmans, V.; Cassady, K.; Yuan, P.; Kofman, I. S.; De Dios, Y. E.; Riascos-Castaneda, R. F.; Wood, S. J.; Bloomberg, J. J.

    2017-01-01

    We have recently completed a long duration head down tilt bed rest (HDBR) study in which we performed structural and functional magnetic resonance brain imaging to identify the relationships between changes in neurocognitive function and neural structural alterations in a spaceflight analog environment. We are also collecting the same measures in crewmembers prior to and following a six month International Space Station mission. We will present data demonstrating that bed rest resulted in functional mobility and balance deterioration with recovery post-HDBR. We observed numerous changes in brain structure, function, and connectivity relative to a control group which were associated with pre to post bed rest changes in sensorimotor function. For example, gray matter volume (GMv) increased in posterior parietal areas and decreased in frontal regions. GMv increases largely overlapped with fluid decreases and vice versa. Larger increases in precentral gyrus (M1)/ postcentral gyrus (S1+2) GMv and fluid decreases were associated with smaller balance decrements. Vestibular activation in the bilateral insular cortex increased with bed rest and subsequently recovered. Larger increases in vestibular activation in multiple brain regions were associated with greater decrements in balance and mobility. We found connectivity increases between left M1 with right S1+2 and the superior parietal lobule, and right vestibular cortex with the cerebellum. Decreases were observed between right Lobule VIII with right S1+2 and the supramarginal gyrus, right posterior parietal cortex (PPC) with occipital regions, and the right superior posterior fissure with right Crus I and II. Connectivity strength between left M1 and right S1+2/superior parietal lobule increased the most in individuals that exhibited the least balance impairments. In sum, we observed HDBR-related changes in measures of brain structure, function, and network connectivity, which correlated with indices of sensorimotor

  13. Isokinetic and isometric strength-endurance after 6 hours of immersion and 6 degrees head-down tilt in men

    Science.gov (United States)

    Shaffer-Bailey, M.; Greenleaf, J. E.; Hutchinson, T. M.

    1996-01-01

    PURPOSE: To determine weight (water) loss levels for onset of muscular strength and endurance changes during deconditioning. METHODS: Seven men (27-40 yr) performed maximal shoulder-, knee-, and ankle-joint isometric (0 degree.s(-1) load) and isokinetic (60 degrees, 120 degrees, 180 degrees.s(-1) velocity) exercise tests during ambulatory control (AC), after 6 h of 6 degrees head-down tilt (HDT; dry-bulb temp. = 23.2 +/- SD 0.6 degrees C, relative humidity = 31.1+/- 11.1%) and after 6 h of 80 degrees foot-down head-out water immersion (WI; water temp. = 35.0 +/- SD 0.1 degree C) treatments. RESULTS: Weight (water) loss after HDT (1.10 +/- SE 0.14 kg, 1.4 +/- 0.2% body wt) and WI (1.54+/- 0.19 kg, 2.0 +/- 0.2% body wt) were not different, but urinary excretion with WI (1,354 +/- 142 ml.6 h(-1)) was 28% greater (p knee at 180 degrees.s(-1) for 30 s) was not different between AC and the WI or HDT treatments. Shoulder-, knee-, and ankle-joint strength was unchanged except for three knee-joint peak torques: AC torque (120 degrees.s(-1), 285 +/- 20 Nm) decreased to 268 +/- 21 Nm (delta = -6%, p torques (180 degrees.s(-1), 260 +/- 19 Nm) decreased to 236 +/- 15 Nm (delta = -9%, p joint strength and endurance decrements is more than 2% body weight (water) loss, while significant reduction in knee-joint muscular strength-endurance occurred only at moderate (120 degrees.s(-1) and lighter (180 degrees.s(-1)) loads with body weight loss of 1.4-2.0% following WI or HDT, respectively. These weight (water) losses and knee-joint strength decrements are somewhat less than the mean weight loss of 2.6% and knee-joint strength decrements of 6-20% of American astronauts after Skylab flights to 84 d.

  14. Effect of 1% Inspired CO2 During Head-Down Tilt on Ocular Structures, Cerebral Blood Flow, and Visual Acuity in Healthy Human Subjects

    Science.gov (United States)

    Laurie, S. S.; Hu, X.; Lee, S. M. C.; Martin, D. S.; Phillips, T. R.; Ploutz-Snyder, R.; Smith, S. M.; Stenger, M. B.; Taibbi, G.; Zwart, S. R.; Vizzeri, G.

    2016-01-01

    The cephalad fluid shift induced by microgravity has been hypothesized to elevate intracranial pressure (ICP) and contribute to the development of the visual impairment/intracranial pressure (VIIP) syndrome experienced by many astronauts during and after long-duration space flight. In addition, elevated ambient partial pressure of carbon dioxide (PCO2) on the International Space Station (ISS) has also been hypothesized to contribute to the development of VIIP. We seek to determine if an acute, mild CO2 exposure, similar to that occurring on the ISS, combined with the cephalad fluid shift induced by head-down tilt will induce ophthalmic and ICP changes consistent with the VIIP syndrome.

  15. Focal Gray Matter Plasticity as a Function of Long Duration Head Down Tilted Bed Rest: Preliminary Results

    Science.gov (United States)

    Koppelmans, V.; Erdeniz, B.; DeDios, Y. E.; Wood, S. J.; Reuter-Lorenz, P. A.; Kofman, I.; Bloomberg, J. J.; Mulavara, A. P.; Seidler, R. D.

    2014-01-01

    Long duration spaceflight (i.e., 22 days or longer) has been associated with changes in sensorimotor systems, resulting in difficulties that astronauts experience with posture control, locomotion, and manual control. The microgravity environment is an important causal factor for spaceflight induced sensorimotor changes. Whether these sensorimotor changes are solely related to peripheral changes from reduced vestibular stimulation, body unloading, body fluid shifts or that they may be related to structural and functional brain changes is yet unknown. However, a recent study reported associations between microgravity and flattening of the posterior eye globe and protrusion of the optic nerve [1] possibly as the result of increased intracranial pressure due to microgravity induced bodily fluid shifts [3]. Moreover, elevated intracranial pressure has been related to white matter microstructural damage [2]. Thus, it is possible that spaceflight may affect brain structure and thereby cognitive functioning. Long duration head down tilt bed rest has been suggested as an exclusionary analog to study microgravity effects on the sensorimotor system [4]. Bed rest mimics microgravity in body unloading and bodily fluid shifts. In consideration of the health and performance of crewmembers both in- and post-flight, we are conducting a prospective longitudinal 70-day bed rest study as an analog to investigate the effects of microgravity on brain structure [5]. Here we present results of the first six subjects. Six subjects were assessed at 12 and 7 days before-, at 7, 30, and 70 days in-, and at 8 and 12 days post 70 days of bed rest at the NASA bed rest facility in UTMB, Galveston, TX, USA. At each time point structural MRI scans (i.e., high resolution T1-weighted imaging and Diffusion Tensor Imaging (DTI)) were obtained using a 3T Siemens scanner. Focal changes over time in gray matter density were assessed using the voxel based morphometry 8 (VBM8) toolbox under SPM

  16. The effects of head-up and head-down tilt on central respiratory chemoreflex loop gain tested by hyperoxic rebreathing.

    Science.gov (United States)

    Skow, Rachel J; Tymko, Michael M; MacKay, Christina M; Steinback, Craig D; Day, Trevor A

    2014-01-01

    Central respiratory chemosensitivity is mediated via chemoreceptor neurons located throughout brain stem tissue. These receptors detect proximal CO2/[H(+)] (i.e., controller gain) and modulate breathing in a classic negative feedback loop. Loop gain (responsiveness) is the theoretical product of controller (chemoreceptors), mixing/feedback (cardiovascular and cerebrovascular systems), and plant (pulmonary system) gains. The level of chemoreceptor stimulation is determined by interactions between mixing and plant gains. The extent to which steady-state changes in body position may affect central chemoreflex loop gain in response to CO2 is unclear. Because of the potential effects of tilt on pulmonary mechanics, we hypothesized that plant gain would be altered by head-up and head-down tilt (HUT, HDT) during hyperoxic rebreathing, which theoretically isolates plant gain by eliminating systemic arterial-tissue gradients. Sixteen subjects (eight females) underwent hyperoxic rebreathing tests on a tilt table to quantify central chemoreflex loop gain in five steady-state positions: 90° HUT, 45° HUT, supine, 45° HDT, and 90° HDT. Respiratory responses (tidal volume, VT; frequency, fR; minute ventilation, VE) were quantified during steady-state and increases in CO2 during rebreathing by linear regression above the ventilatory recruitment threshold (VRT). Using one-factor analysis of variance, we found that there were no differences in the respiratory responses between the five positions (VRT, P=0.711; VT, P=0.290; fR, P=0.748; VE, P=0.325). Our findings suggest that during steady-state orthostatic stress, the ability of subjects to mount a normal ventilatory response to increased CO2 was unaffected, despite any potential changes in pulmonary mechanics associated with positional challenges.

  17. Computer simulation of the effect of dDAVP with saline loading on fluid balance after 24-hour head-down tilt

    Science.gov (United States)

    Srinivasan, R. S.; Simanonok, K. E.; Charles, J. B.

    1994-01-01

    Fluid loading (FL) before Shuttle reentry is a countermeasure currently in use by NASA to improve the orthostatic tolerance of astronauts during reentry and postflight. The fluid load consists of water and salt tablets equivalent to 32 oz (946 ml) of isotonic saline. However, the effectiveness of this countermeasure has been observed to decrease with the duration of spaceflight. The countermeasure's effectiveness may be improved by enhancing fluid retention using analogs of vasopressin such as lypressin (LVP) and desmopressin (dDAVP). In a computer simulation study reported previously, we attempted to assess the improvement in fluid retention obtained by the use of LVP administered before FL. The present study is concerned with the use of dDAVP. In a recent 24-hour, 6 degree head-down tilt (HDT) study involving seven men, dDAVP was found to improve orthostatic tolerance as assessed by both lower body negative pressure (LBNP) and stand tests. The treatment restored Luft's cumulative stress index (cumulative product of magnitude and duration of LBNP) to nearly pre-bedrest level. The heart rate was lower and stroke volume was marginally higher at the same LBNP levels with administration of dDAVP compared to placebo. Lower heart rates were also observed with dDAVP during stand test, despite the lower level of cardiovascular stress. These improvements were seen with only a small but significant increase in plasma volume of approximately 3 percent. This paper presents a computer simulation analysis of some of the results of this HDT study.

  18. The implementation of game in a 20-day head-down tilting bed rest experiment upon mood status and neurotic levels of rest subjects

    Science.gov (United States)

    Ishizaki, Yuko; Fukuoka, Hideoki; Ishizaki, Tatsuro; Tanaka, Hidetaka; Ishitobi, Hiromi

    2004-12-01

    This study evaluated the effect of the implementation of game on mental health among participants in a bed rest (BR) experiment. Subjects were 12 healthy males aged 20-26, who participated in a 20-day 6-degrees head-down tilting BR experiment. The participants were asked to complete psychometrical questionnaires before, during, and after the experiment. We entrusted the participants to manage their leisure time and they intended a game in which all of them could take part over the experiment period. The general conversation and light-hearted mood among the subjects continued during the experimental period. Longitudinal data analysis showed that levels of neurosis and mood status did not deteriorate during the experiment, while our previous experiments, which were performed under the same protocol as this study except for the implementation of the game showed a distinct deterioration in psychosocial status. We consider that the implementation of game autonomously contributes to the positive effects on the mental health among the participants.

  19. Effects of short-term exposure to head-down tilt on cerebral hemodynamics: a prospective evaluation of a spaceflight analog using phase-contrast MRI

    Science.gov (United States)

    Ambarki, Khalid; Eklund, Anders; Malm, Jan; Mulder, Edwin; Gerlach, Darius; Rittweger, Jörn

    2016-01-01

    Alterations in cerebral hemodynamics in microgravity are hypothesized to occur during spaceflight and could be linked to the Visual Impairment and Intracranial Pressure syndrome. Head-down tilt (HDT) is frequently used as a ground-based analog to simulate cephalad fluid shifts in microgravity; however, its effects on cerebral hemodynamics have not been well studied with MRI techniques. Here, we evaluate the effects of 1) various HDT angles on cerebral arterial and venous hemodynamics; and 2) exposure to 1% CO2 during an intermediate HDT angle (−12°) as an additional space-related environmental factor. Blood flow, cross-sectional area (CSA), and blood flow velocity were measured with phase-contrast MRI in the internal jugular veins, as well as the vertebral and internal carotid arteries. Nine healthy male subjects were measured at baseline (supine, 0°) and after 4.5 h of HDT at −6°, −12° (with and without 1% CO2), and −18°. We found a decrease in total arterial blood flow from baseline during all angles of HDT. On the venous side, CSA increased with HDT, and outflow decreased during −12° HDT (P = 0.039). Moreover, the addition of 1% CO2 to −12° HDT caused an increase in total arterial blood flow (P = 0.016) and jugular venous outflow (P < 0.001) compared with −12° HDT with ambient atmosphere. Overall, the results indicate decreased cerebral blood flow during HDT, which may have implications for microgravity-induced cerebral hemodynamic changes. PMID:27013606

  20. A comparison of autonomic responses in humans induced by two simulation models of weightlessness: lower body positive pressure and 6 degrees head-down tilt.

    Science.gov (United States)

    Fu, Q; Sugiyama, Y; Kamiya, A; Mano, T

    2000-04-12

    Six-degree head-down tilt (HDT) is well accepted as an effective weightlessness model in humans. However, some researchers utilized lower body positive pressure (LBPP) to simulate the cardiovascular and renal effects of a decreased gravitational stress. In order to determine whether LBPP was a suitable model for simulated weightlessness, we compared the differences between these two methods. Ten healthy males, aged 21-41 years, were subjected to graded LBPP at 10, 20 and 30 mmHg, as well as 6 degrees HDT. Muscle sympathetic nerve activity (MSNA) was microneurographically recorded from the tibial nerve along with cardiovascular variables. We found that MSNA decreased by 27% to a similar extent both at low levels of LBPP (10 and 20 mmHg) and HDT. However, at a high level of LBPP (30 mmHg), MSNA tended to increase. Mean arterial pressure was elevated significantly by 11% (10 mmHg) at 30 mmHg LBPP, but remained unchanged at low levels of LBPP and HDT. Heart rate did not change during the entire LBPP and HDT procedures. Total peripheral resistance markedly increased by 36% at 30 mmHg LBPP, but decreased by 9% at HDT. Both stroke volume and cardiac output tended to decrease at 30 mmHg LBPP, but increased at HDT. These results suggest that although both LBPP and HDT induce fluid shifts from the lower body toward the thoracic compartment, autonomic responses are different, especially at LBPP greater than 20 mmHg. We note that high levels of LBPP (>20 mmHg) activate not only cardiopulmonary and arterial baroreflexes, but also intramuscular mechanoreflexes, while 6 degrees HDT only activates cardiopulmonary baroreflexes. We conclude that LBPP is not a suitable model for simulated weightlessness in humans.

  1. Assessment of lumbar intervertebral disc glycosaminoglycan content by gadolinium-enhanced MRI before and after 21-days of head-down-tilt bedrest.

    Directory of Open Access Journals (Sweden)

    Timmo Koy

    Full Text Available During spaceflight, it has been shown that intervertebral discs (IVDs increase in height, causing elongation of the spine up to several centimeters. Astronauts frequently report dull lower back pain that is most likely of discogenic origin and may result from IVD expansion. It is unknown whether disc volume solely increases by water influx, or if the content of glycosaminoglycans also changes in microgravity. Aim of this pilot study was to investigate effects of the spaceflight analog of bedrest on the glycosaminoglycan content of human lumbar IVDs. Five healthy, non-smoking, male human subjects of European descent were immobilized in 6° head-down-tilt bedrest for 21 days. Subjects remained in bed 24 h a day with at least one shoulder on the mattress. Magnetic Resonance Imaging (MRI scans were taken according to the delayed gadolinium-enhanced magnetic resonance imaging (dGEMRIC protocol before and after bedrest. The outcome measures were T1 and ΔT1. Scans were performed before and after administration of the contrast agent Gd-DOTA, and differences between T1-values of both scans (ΔT1 were computed. ΔT1 is the longitudinal relaxation time in the tissue and inversely related to the glycosaminoglycan-content. For data analysis, IVDs L1/2 to L4/5 were semi-automatically segmented. Zones were defined and analyzed separately. Results show a highly significant decrease in ΔT1 (p<0.001 after bedrest in all IVDs, and in all areas of the IVDs. The ΔT1-decrease was most prominent in the nucleus pulposus and in L4/5, and was expressed slightly more in the posterior than anterior IVD. Unexpected negative ΔT1-values were found in Pfirrmann-grade 2-discs after bedrest. Significantly lower T1 before contrast agent application was found after bedrest compared to before bedrest. According to the dGEMRIC-literature, the decrease in ΔT1 may be interpreted as an increase in glycosaminoglycans in healthy IVDs during bedrest. This interpretation seems

  2. Spectral components of human cardiovascular responses to step changes in Lower Body Negative Pressure (LBNP) before and after 22 hour of 6 deg head down bed rest

    Science.gov (United States)

    Knapp, C. F.; Evans, J. M.; Grande, K. J.; Murphy, C. D.; Patwardhan, A. R.

    1992-01-01

    Changes in autonomic outflow to peripheral organs during the development of bedrest induced orthostatic intolerance have not been determined. Recent studies have indicated that spectral analysis provides an indirect assessment of these changes. Eight male subjects were studied before and after 22 hours of 6 degree head down bedrest plus Lasix (40 mg. P.P.). Cardiovascular spectra (using an autoregressive technique) were determined for heart rate (HR, ECG), arterial pressure (AP, Finapres), radial artery flow (RF, Hokansen) and respiration rate (RR, BoMed). Spectra were obtained from 2.5 minute segments during control, lower body negative pressure (minus 10, 20, 30, 40, 50 mmHg) and recovery. Bedrest increased HR spectra power in the low frequency (.001 to .041 Hz) range, increased RF power in the low and mid (.04 to .18 Hz) range and increased AP power in the high (.18 to .50 Hz) frequency range. Increasing levels of lower body negative pressure decreased HR power and increased RF power in the high frequency range and decreased AP power in the low frequency range. Since spectral power of HR in the high frequency range has been shown to indicate parasympathetically mediated regulation and power in the low and mid frequency ranges indicates a sympathetic / parasympathetic mixture, then both bedrest and lower body negative pressure appeared to shift sympathetic / parasympathetic balance toward sympathetic regulation of HR. The interpretation of the spectral content of AP and RF with respect to their autonomic origins remains unclear.

  3. Exploring a possible origin of a 14 deg y-normal spin tilt at RHIC polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-06-15

    A possible origin of a 14 deg y-normal spin n0 tilt at the polarimeter is in snake angle defects. This possible cause is investigated by scanning the snake axis angle µ, and the spin rotation angle at the snake, φ, in the vicinity of their nominal values.

  4. Behavioral and Psychological Issues in Long Duration Head-down Bed Rest

    Science.gov (United States)

    Seaton, Kimberly A.; Bowie, Kendra; Sipes, Walter A.

    2008-01-01

    Behavioral health services, similar to those offered to the U.S. astronauts who complete six-month missions on board the International Space Station, were provided to 13 long-duration head-down bed rest participants. Issues in psychological screening, selection, and support are discussed as they relate to other isolated and confined environments. Psychological services offered to participants are described, and challenges in subject selection and retention are discussed. Psychological support and training provided to both subjects and study personnel have successfully improved the well-being of study participants. Behavioral health services are indispensable to long-duration head-down tilt bed rest studies.

  5. Influence of long-term head-down body position on innervation density in extremity blood vessels

    Science.gov (United States)

    Lorant, M.; Raffai, G.; Nadasy, G.; Feher, E.; Monos, E.

    2001-01-01

    The aim of the present study was to quantitate and compare the density of nerve terminals (NTD), as well as of their synaptic vesicle population (SyVD) in saphenous and brachial vein and artery, obtained from rats maintained in the horizontal or head-down tilted (HDT) position for two weeks. The same technique was applied as that for the head-up tilt study.

  6. Effects of Mild Hypercapnia During Head-Down Bed Rest on Ocular Structures, Cerebral Blood Flow, aud Visual Acuity in Healthy Human Subjects

    Science.gov (United States)

    Laurie, S. S.; Taibbi, G.; Lee, S. M. C.; Martin, D. S.; Zanello, S.; Ploutz-Snyder, R.; Hu, X.; Stenger, M. B.; Vizzeri, G.

    2014-01-01

    The cephalad fluid shift induced by microgravity has been hypothesized to cause an elevation in intracranial pressure (ICP) and contribute to the development of the Visual Impairment/Intracranial Pressure (VIIP) syndrome, as experienced by some astronauts during long-duration space flight. Elevated ambient partial pressure of carbon dioxide (PCO2) on ISS may also raise ICP and contribute to VIIP development. We seek to determine if the combination of mild CO2 exposure, similar to that occurring on the International Space Station, with the cephalad fluid shift induced by head-down tilt, will induce ophthalmic and cerebral blood flow changes similar to those described in the VIIP syndrome. We hypothesize that mild hypercapnia in the head-down tilt position will increase choroidal blood volume and cerebral blood flow, raise intraocular pressure (IOP), and transiently reduce visual acuity as compared to the seated or the head-down tilt position without elevated CO2, respectively.

  7. The influence of gravity on regional lung blood flow in humans: SPECT in the upright and head-down posture.

    Science.gov (United States)

    Ax, M; Sanchez-Crespo, A; Lindahl, S G E; Mure, M; Petersson, J

    2017-06-01

    Previous studies in humans have shown that gravity has little influence on the distribution of lung blood flow while changing posture from supine to prone. This study aimed to evaluate the maximal influence of posture by comparison of regional lung blood flow in the upright and head-down posture in 8 healthy volunteers, using a tilt table. Regional lung blood flow was marked by intravenous injection of macroaggregates of human albumin labeled with (99m)Tc or (113m)In, in the upright and head-down posture, respectively, during tidal breathing. Both radiotracers remain fixed in the lung after administration. The distribution of radioactivity was mapped using quantitative single photon emission computed tomography (SPECT) corrected for attenuation and scatter. All images were obtained supine during tidal breathing. A shift from upright to the head-down posture caused a clear redistribution of blood flow from basal to apical regions. We conclude that posture plays a role for the distribution of lung blood flow in upright humans, and that the influence of posture, and thereby gravity, is much greater in the upright and head-down posture than in horizontal postures. However, the results of the study demonstrate that lung structure is the main determinant of regional blood flow and gravity is a secondary contributor to the distribution of lung blood flow in the upright and head-down positions.NEW & NOTEWORTHY Using a dual-isotope quantitative SPECT method, we demonstrated that although a shift in posture redistributes blood flow in the direction of gravity, the results are also consistent with lung structure being a greater determinant of regional blood flow than gravity. To our knowledge, this is the first study to use modern imaging methods to quantify the shift in regional lung blood flow in humans at a change between the upright and head-down postures. Copyright © 2017 the American Physiological Society.

  8. Effects of head-down bed rest on complex heart rate variability: Response to LBNP testing

    Science.gov (United States)

    Goldberger, Ary L.; Mietus, Joseph E.; Rigney, David R.; Wood, Margie L.; Fortney, Suzanne M.

    1994-01-01

    Head-down bed rest is used to model physiological changes during spaceflight. We postulated that bed rest would decrease the degree of complex physiological heart rate variability. We analyzed continuous heart rate data from digitized Holter recordings in eight healthy female volunteers (age 28-34 yr) who underwent a 13-day 6 deg head-down bed rest study with serial lower body negative pressure (LBNP) trials. Heart rate variability was measured on a 4-min data sets using conventional time and frequency domain measures as well as with a new measure of signal 'complexity' (approximate entropy). Data were obtained pre-bed rest (control), during bed rest (day 4 and day 9 or 11), and 2 days post-bed rest (recovery). Tolerance to LBNP was significantly reduced on both bed rest days vs. pre-bed rest. Heart rate variability was assessed at peak LBNP. Heart rate approximate entropy was significantly decreased at day 4 and day 9 or 11, returning toward normal during recovery. Heart rate standard deviation and the ratio of high- to low-power frequency did not change significantly. We conclude that short-term bed rest is associated with a decrease in the complex variability of heart rate during LBNP testing in healthy young adult women. Measurement of heart rate complexity, using a method derived from nonlinear dynamics ('chaos theory'), may provide a sensitive marker of this loss of physiological variability, complementing conventional time and frequency domain statistical measures.

  9. Increased Brain Activation for Dual Tasking with 70-Days Head-Down Bed Rest

    Science.gov (United States)

    Yuan, Peng; Koppelmans, Vincent; Reuter-Lorenz, Patricia A.; De Dios, Yiri E.; Gadd, Nichole E.; Wood, Scott J.; Riascos, Roy; Kofman, Igor S.; Bloomberg, Jacob J.; Mulavara, Ajitkumar P.; Seidler, Rachael D.

    2016-01-01

    Head-down tilt bed rest (HDBR) has been used as a spaceflight analog to simulate the effects of microgravity exposure on human physiology, sensorimotor function, and cognition on Earth. Previous studies have reported that concurrent performance of motor and cognitive tasks can be impaired during space missions. Understanding the consequences of HDBR for neural control of dual tasking may possibly provide insight into neural efficiency during spaceflight. In the current study, we evaluated how dual task performance and the underlying brain activation changed as a function of HDBR. Eighteen healthy men participated in this study. They remained continuously in the 6° head-down tilt position for 70 days. Functional MRI for bimanual finger tapping was acquired during both single task and dual task conditions, and repeated at 7 time points pre-, during- and post-HDBR. Another 12 healthy males participated as controls who did not undergo HDBR. A widely distributed network involving the frontal, parietal, cingulate, temporal, and occipital cortices exhibited increased activation for dual tasking and increased activation differences between dual and single task conditions during HDBR relative to pre- or post-HDBR. This HDBR-related brain activation increase for dual tasking implies that more neurocognitive control is needed for dual task execution during HDBR compared to pre- and post-HDBR. We observed a positive correlation between pre-to-post HDBR changes in dual-task cost of reaction time and pre-to-post HDBR change in dual-task cost of brain activation in several cerebral and cerebellar regions. These findings could be predictive of changes in dual task processing during spaceflight. PMID:27601982

  10. Changes in endotracheal tube cuff pressure during laparoscopic surgery in head-up or head-down position

    Science.gov (United States)

    2014-01-01

    Background The abdominal insufflation and surgical positioning in the laparoscopic surgery have been reported to result in an increase of airway pressure. However, associated effects on changes of endotracheal tube cuff pressure are not well established. Methods 70 patients undergoing elective laparoscopic colorectal tumor resection (head-down position, n = 38) and laparoscopic cholecystecomy (head-up position, n = 32) were enrolled and were compared to 15 patients undergoing elective open abdominal surgery. Changes of cuff and airway pressures before and after abdominal insufflation in supine position and after head-down or head-up positioning were analysed and compared. Results There was no significant cuff and airway pressure changes during the first fifteen minutes in open abdominal surgery. After insufflation, the cuff pressure increased from 26 ± 3 to 32 ± 6 and 27 ± 3 to 33 ± 5 cmH2O in patients receiving laparoscopic cholecystecomy and laparoscopic colorectal tumor resection respectively (both p < 0.001). The head-down tilt further increased cuff pressure from 33 ± 5 to 35 ± 5 cmH2O (p < 0.001). There six patients undergoing colorectal tumor resection (18.8%) and eight patients undergoing cholecystecomy (21.1%) had a total increase of cuff pressure more than 10 cm H2O (18.8%). There was no significant correlation between increase of cuff pressure and either the patient's body mass index or the common range of intra-abdominal pressure (10-15 mmHg) used in laparoscopic surgery. Conclusions An increase of endotracheal tube cuff pressure may occur during laparoscopic surgery especially in the head-down position. PMID:25210501

  11. Microvascular responses to body tilt in cutaneous maximus muscle of conscious rats

    Science.gov (United States)

    Puri, Rohit K.; Segal, Steven S.

    1994-01-01

    We investigated microvascular responses to head-up tilt (HUT) and head-down tilt (HDT) in striated muscle of conscious male rats. To observe the microcirculation in the cutaneous maximus muscle, a transparent polycarbonate chamber was implanted aseptically into a skin fold created between the shoulders. Rats were trained to sit quietly during HUT and HDT while positioned on a horizontal microscope that rotated in the sagittal plane. At 4-5 days after surgery, arteriole and venule diameters were recorded using videomicroscopy while the rat experienced 10 min each (in random order) of HUT or HDT at 20 deg or 40 deg separated by 2-h rest periods. HUT had no affect on microvessel diameter; 20 deg HDT had little affect. In response to 40 deg HDT, 'large' arterioles constricted by 18 +/- 2% and 'small' arterioles dilated by 21 +/- 3%; this difference suggested variation in mechanisms controlling arteriolar responses. Venules exhibited a larger fluctuation in diameter during 40 deg HDT compared with other body positions, suggesting that venomotor activity may be induced with sufficient fluid shift or change in central venous pressure. These observations illustrate a viable model for studying microvascular responses to gravitational stress in conscious rats.

  12. Analysis of Arterial Mechanics During Head-Down-Tilt Bed Rest

    Science.gov (United States)

    Elliott, Morgan B.; Martin, David S.; Westby, Christian M.; Stenger, Michael B.; Platts, Steven H.

    2014-01-01

    Carotid, brachial, and tibial arteries reacted differently to HDTBR. Previous studies have not analyzed the mechanical properties of the human brachial or anterior tibial arteries. After slight variations during bed-rest, arterial mechanical properties and IMT returned to pre-bed rest values, with the exception of tibial stiffness and PSE, which continued to be reduced post-bed rest while the DC remained elevated. The tibial artery remodeling was probably due to decreased pressure and volume. Resulting implications for longer duration spaceflight are unclear. Arterial health may be affected by microgravity, as shown by increased thoracic aorta stiffness in other ground based simulations (Aubert).

  13. Countermeasures and Functional Testing in Head-Down Tilt Bed Rest (CFT 70)

    Science.gov (United States)

    Cromwell, Ronita L.

    2013-01-01

    This 70-day bed rest campaign was comprised of 6 integrated studies and conducted at the NASA Flight Analogs Research Unit (FARU). The FARU is located at the University of Texas Medical Branch, Galveston, Texas and is a satellite unit of the Institute for Translational Sciences - Clinical Research Center. This presentation will describe the FARU, discuss the utility of the bed rest platform for use in these studies, and introduce the studies that participated in the CFT 70 bed rest campaign. Information in this presentation will serve as the background for subsequent talks from each individual study. Individual study presentations will discuss preliminary results from completed subjects. Studies included in CFT70 were: ? Physiological Factors Contributing to Post Flight Changes in Functional Performance. J. Bloomberg, NASA ? Integrated Resistance and Aerobic Training Study. L. Ploutz-Snyder, USRA ? Testosterone Supplementation as a Countermeasure Against Musculoskeletal losses during Space Exploration. R. Urban, University of Texas Medical Branch ? Effects of Retronasal Smelling, Variety and Choice on Appetite & Satiety. J. Hunter, Cornell University ? AD ASTRA: Automated Detection of Attitudes and States through Transaction Recordings Analysis. C. Miller, Smart Information Flow Technologies, LLC ? Bed Rest as a Spaceflight Analog to Study Neuro-cognitive Changes: Extent, Longevity, and Neural Bases. R. Seidler, University of Michigan

  14. High dietary sodium chloride causes further protein loss during head-down tilt bed rest (HDBR)

    Science.gov (United States)

    Buehlmeier, Judith; Frings-Meuthen, Petra; Baecker, Natalie; Stehle, Peter; Heer, Martina

    Human spaceflight is associated with a loss of body protein most likely caused by muscle degradation. Additionally astronauts tend towards a high dietary intake of sodium chloride (NaCl), which has recently been shown to induce low grade metabolic acidosis (Frings-Meuthen et al. JBMR, Epub 2007). In several patterns, e.g. chronical renal failure, metabolic acidosis is associated with protein catabolism. We therefore hypothesized that high dietary intake of NaCl enforces protein losses in HDBR, a model for physiological changes in microgravity (µG). Eight healthy male subjects (mean age 26.25 ± 3.5; mean body weight: 78.5 ± 4.1 kg) participated in a 14-day bed rest study in the metabolic ward of the DLR - Institute of Aerospace Medicine, Cologne, Germany. The study was carried out in a cross over design, consisting of two phases, each lasting 22 days (5 days adaptation, 14 days 6° HDBR and 3 days recovery). Both study phases were identical with respect to environmental conditions and study protocol. Subjects received an individually tailored, weight-maintaining diet containing 1.3 g protein/kg/day. The diet was identical in both study phases with the exception of NaClintake: Every subject received a low NaCl diet (0.7 mmol/kg/day) in one phase and a high NaCl diet (7.7 mmol/kg/day) in another one. Blood gas for analysis of acid-base balance was implemented at days 4 and 5 of adaptation, days 2, 5, 7, 10, 12, 14 of HDBR and days 2, 3 of recovery. Continuous urine collection started on the first day in the metabolic ward to analyze nitrogen excretion. Nitrogen balance was calculated from the difference between protein intake and urinary nitrogen excretion, determined by use of chemiluminescence (Grimble et al. JPEN, 1988). Plasma pH did not change significantly (p=0.285), but plasma bicarbonate and base excess decreased (p=0.0175; p=0.0093) with high NaCl intake in HDBR compared to the low NaCl diet. Nitrogen balance in HDBR was negative, as expected in immobilization with low NaCl diet ( 0.34 ± 1.2 g/d). However, high NaCl intake in HDBR exacerbated the negative nitrogen balance to 1.34 ± 1.0 g/d (p¡0.001) compared to low NaCl. We conclude that high dietary NaCl intake induces low grade metabolic acidosis during HDBR. Low grade metabolic acidosis may be a reason for an increased protein turnover reflected by an exaggerated negative nitrogen balance in HDBR. Accordingly, a high dietary NaCl intake may exacerbate loss of body protein in µG via low grade metabolic acidosis.

  15. Model for antiorthostatic hypokinesia - Head-down tilt effects on water and salt excretion

    Science.gov (United States)

    Deavers, D. R.; Musacchia, X. J.; Meininger, G. A.

    1980-01-01

    Water and electrolyte excretion was investigated in antiorthostatic hypokinetic and orthostatic hypokinetic and control rats in metabolic cages. Significant (t test, P less than 0.05) diuresis, natriuresis, and kaliuresis occurred in the antiorthostatic hypokinetic subjects but did not occur in either the orthostatic hypokinetic or controls. Recovery from antiorthostatic hypokinesia was characterized by retention of water, sodium, and potassium. Patterns of changes in body weight and food and water consumption were virtually identical in antiorthostatic and orthostatic hypokinetic rats and thus could not account for the differences in renal handling of water and electrolytes. Also, differences in ingestion of food and water in controls could not account for differences in excretion of water and electrolytes between these and antiorthostatic hypokinetic rats. It was concluded that the antiorthostatic position was responsible for the diuresis and natriuresis and that the antiorthostatic hypokinetic rat appears to be a good model for the study of water and elecrolyte excretion during conditions such as bed rest, water immersion, and exposure to weightlessness.

  16. Exercise Thermoregulation in Men after One and 24-hours of 6 Degree Head-Down Tilt

    Science.gov (United States)

    Ertl, A. C.; Dearborn, A. S.; Weldhofer, A. R.; Bernauer, E. M.; Greenleaf, J. E.

    1998-01-01

    Exercise thermoregulation exercise is dependent on heat loss by increased skin blood flow (convective and conductive heat loss) and through enhanced sweating (evaporative heat loss). Reduction of plasma volume (PV), increased plasma osmolality, physical deconditioning, and duration of exposure to simulated and actual microgravity reduces the ability to thermoregulate during exercise.

  17. Effects of Head-down Tilt on Nerve Conduction in Rhesus Monkeys

    Directory of Open Access Journals (Sweden)

    Bo Sun

    2017-01-01

    Conclusions: This study demonstrates that the compound muscle action potential amplitudes of nerves are decreased under simulated microgravity in rhesus monkeys. Moreover, rhesus monkeys exposed to HDT might be served as an experimental model for the study of NCS under microgravity.

  18. Left ventricular remodeling during and after 60 days of sedentary head-down bed rest.

    Science.gov (United States)

    Westby, Christian M; Martin, David S; Lee, Stuart M C; Stenger, Michael B; Platts, Steven H

    2016-04-15

    Short periods of weightlessness are associated with reduced stroke volume and left ventricular (LV) mass that appear rapidly and are thought to be largely dependent on plasma volume. The magnitude of these cardiac adaptations are even greater after prolonged periods of simulated weightlessness, but the time course during and the recovery from bed rest has not been previously described. We collected serial measures of plasma volume (PV, carbon monoxide rebreathing) and LV structure and function [tissue Doppler imaging, three-dimensional (3-D) and 2-D echocardiography] before, during, and up to 2 wk after 60 days of 6° head down tilt bed rest (HDTBR) in seven healthy subjects (four men, three women). By 60 days of HDTBR, PV was markedly reduced (2.7 ± 0.3 vs. 2.3 ± 0.3 liters,PResting measures of LV volume and mass were ∼15% (Prest values (P< 0.001). As previously reported, decreased PV and LV volume precede and likely contribute to cardiac atrophy during prolonged LV unloading. Although PV and LV volume recover rapidly after HDTBR, there is no concomitant normalization of LV mass. These results demonstrate that reduced LV mass in response to prolonged simulated weightlessness is not a simple effect of tissue dehydration, but rather true LV muscle atrophy that persists well into recovery.

  19. Body fluid alterations during head-down bed rest in men at moderate altitude

    Science.gov (United States)

    Loeppky, J. A.; Roach, R. C.; Selland, M. A.; Scotto, P.; Luft, F. C.; Luft, U. C.

    1993-01-01

    To determine the effects of hypoxia on fluid balance responses to simulated zero-gravity, measurements were made in six subjects before and during -5 deg continuous head-down bed rest (HDBR) over 8 d at 10,678 ft. The same subjects were studied again at this altitude without HDBR as a control (CON) using a cross-over design. During this time, they maintained normal upright day-time activities, sleeping in the horizontal position at night. Fluid balance changes during HDBR in hypoxia were more pronounced than similar measurements previously reported from HDBR studies at sea level. Plasma volume loss was slightly greater and the diuresis and natriuresis were doubled in magnitude as compared to previous studies in normoxia and sustained for 4 d during hypoxia. These changes were associated with an immediate but transient rise in plasma atrial natriuretic peptide (ANP) to day 4 of 140 percent in HDBR and 41 percent in CON (p less than 0.005), followed by a decline towards baseline. Differences were less striking between HDBR and CON for plasma antidiuretic hormone and aldosterone, which were transiently reduced by HDBR. Plasma catecholamines showed a similar pattern to ANP in both HDBR and CON, suggesting that elevated ANP and catecholamines together accounted for the enhanced fluid shifts with HDBR during hypoxia.

  20. Metabolic responses to head-down suspension in hypophysectomized rats

    Science.gov (United States)

    Woodman, C. R.; Tipton, C. M.; Evans, J.; Linderman, J. K.; Gosselink, K.; Grindeland, R. E.

    1993-01-01

    Rats exposed to head-down suspension (HDS) exhibit reductions in maximal O2 consumption (VO2max) and atrophy of select hindlimb muscles. This study tested the hypothesis that an endocrine-deficient rat exposed to HDS would not exhibit reductions in VO2max or hindlimb muscle mass. Hypophysectomized (HYPX) and sham-operated (SHAM) rats were tested for VO2max before and after 28 days of HDS or cage control (CC) conditions. No significant reductions in VO2max were observed in HYPX rats. In contrast, SHAM-HDS rats exhibited a significant reduction in absolute (-16%) and relative (-29%) measures of aerobic capacity. Time course experiments revealed a reduction in VO2max in SHAM-HDS rats within 7 days, suggesting that cardiovascular adjustments to HDS occurred in the 1st wk. HDS was associated with atrophy of the soleus (-42%) in SHAM rats, whereas HYPX rats exhibited atrophy of the soleus (-36%) and plantaris (-13%). SHAM-HDS rats had significantly lower (-38%) soleus citrate synthase activities per gram muscle mass than SHAM-CC, but no significant differences existed between HYPX-HDS and -CC rats. HDS rats had an impaired ability to thermoregulate, as indicated by significantly greater temperature increases per unit run time, compared with their CC counterparts. Pretreatment plasma epinephrine levels were significantly lower in HYPX than in SHAM rats. Norepinephrine concentration was similar for all groups except HYPX-HDS, in which it was significantly higher. HDS had no significant effect on thyroxine or triiodothyronine. SHAM-HDS rats had significantly lower concentrations of testosterone and growth hormone.(ABSTRACT TRUNCATED AT 250 WORDS).

  1. Heart rate and blood pressure response to short-term head-down bed rest: a nonlinear approach.

    Science.gov (United States)

    Balocchi, R; Di Garbo, A; Michelassi, C; Chillemi, S; Varanini, M; Barbi, M; Legramante, J M; Raimondi, G; Zbilut, J P

    2000-06-01

    Although it is well-known that prolonged exposure to microgravity environment such as in space travel results in derangements of orthostasis, recent evidence suggests that even short-term exposure may have similar effects and parallels such common examples as prolonged bed rest. Whereas spectral analysis of heart rate and systolic blood pressure have been unable to detect changes, we hypothesized that nonlinear indexes may be better able to uncover such perturbations. Eighteen healthy subjects were exposed to 4-hour head-down tilt, and of these, 4 exhibited fainting. Two nonlinear indexes, mutual information and recurrence quantification were used to analyze the data. Only recurrence quantification was able to detect a "decoupling" of heart rate and systolic blood pressure at rest using discriminant analysis (p < 0.05). These results suggest that orthostatic intolerance may be due to a decoupling of heart rate from systolic blood pressure reflexive activity occurring at rest.

  2. LBNP/ergometer effects on female cardiovascular and muscle deconditioning in 15d head-down bed rest

    Science.gov (United States)

    Wang, Lin-Jie

    2012-07-01

    Female has already been an important part of astronaut corps but gender characteristics in weightlessness and countermeasure effects still not clearly elucidated. In this study the LBNP/Ergometer effects on female cardiovascular deconditioning and muscle atrophy in 15d head-down bed rest were explored. 22 female university students were recruited as volunteers that participated in the 15d head-down bed rest. They were divided into control group (Con,n=8), LBNP exercise group (LBNP,n=7) and LBNP combined with ergometer exercise group (LBNP+Ergo, n=7). Grade negative pressures of -10,-20,-30,-40mmHg 20 or 55min were used in LBNP exercise. In ergometer exercises the subjects must maintain 60-80% VO2peak of pre-bed rest at pedal speed of about 70cycle/min for 15min and the entire exercise duration was 30min. LBNP were performed at 6th,8th,10th,12th,and 13th day and Ergometer were operated at 4th,5th,7th,9th,11th day during bed rest. Before and after bed rest, cardiovascular tilt test were performed to evaluate orthostatic intolerance, supine cycle ergometer were used to test the cardiopulmonary function, MRI tests were operated to examine the volume variations of leg muscle groups and isokinetic test were given to test the muscle strength and endurance of knee. 40% of female subjects did not pass the tilt table test after bed rest and exercises made no difference. Compared with pre-BR, VO2max and VO2max /body weight, VO2/HRmax, maximal power and duration significantly decreased in CON group and LBNP group. For the ERGO+LBNP group, there were no visible different in the parameters of cardiopulmonary function except that maximal power and duration decreased. Muscle maximal voluntary contraction and muscle (quadriceps, rectus femoris, gastrocnemius and soleus) volume decreasing in non-predominant leg was larger in Con group than in LBNP+Ergo group. It is suggested that LBNP combined with ergometer in some degrees can counteract the cardiovascular and muscle deconditioning

  3. Effect of tilting on oxygenation in newborn infants.

    OpenAIRE

    Thoresen, M; Cowan, F.; Whitelaw, A

    1988-01-01

    Transcutaneous (tc) PO2 in newborn infants increased on head up tilting (median increase 0.5 kPa at term, 1.0 kPa preterm). Head down tilting was associated with an equivalent fall in tcPO2. There was no change in tcPCO2. Tilting of infants mechanically ventilated for respiratory distress syndrome or surgery produced no consistent change in PO2.

  4. Knee-Joint Proprioception During 30-Day 6 deg Head-Down Bed Rest with Isotonic and Isokinetic Exercise Training

    Science.gov (United States)

    Bernauer, E. M.; Walby, W. F.; Ertl, A. C.; Dempster, P. T.; Bond, M.; Greenleaf, J. E.

    1994-01-01

    To determine if daily isotonic exercise or isokinetic exercise training coupled with daily log proprioceptive training, would influence log proprioceptive tracking responses during Bed Rest (BR), 19 men (36 +/- SD 4 years, 178 +/- 7 cm, 76.8 +/- 7.8 kg) were allocated into a NO-Exercise (NOE) training control group (n = 5), and IsoTanic Exercise (ITE, n = 7) and IsoKinetic Exercise (IKE, n = 7) training groups. Exercise training was conducted during BR for two 30-min period / d, 5 d /week. Only the IKE group performed proprioceptive training using a now isokinetic procedure with each lower extremity for 2.5 min before and after the daily exercise training sessions; proprioceptive testing occurred weekly for all groups. There were no significant differences in proprioceptive tracking scores, expressed as a percentage of the perfect score of 100, in the pro-BR ambulatory control period between the three groups. Knee extension and flexion tracking responses were unchanged with NOE during BR, but were significantly greater (*p less than 0.05) at the end of BR in both exercise groups when compared with NOE responses (extension: NOE 80.7 +/- 0.7%, ITE 82.9 +/- 0.6%, IKE 86.5* +/- 0.7%; flexion: NOE 77.6 +/- 1.50, ITE 80.0 +/- 0.8% (NS), IKE 83.6* +/- 0.8%). Although proprioceptive tracking was unchanged during BR with NOE, both lsotonic exercise training (without additional propriaceptive training) and especially isokinetic exercise training when combined with daily proprioceptive training, significantly improved knee proprioceptive tracking responses after 30 d of BR.

  5. Sympathetic nervous activity decreases during head-down bed rest but not during microgravity

    DEFF Research Database (Denmark)

    Christensen, Niels J; Heer, Martina; Ivanova, Krassimira

    2005-01-01

    We tested the hypothesis that sympathoadrenal activity in humans is low during spaceflight and that this effect can be simulated by head-down bed rest (HDBR). Platelet norepinephrine and epinephrine were measured as indexes of long-term changes in sympathoadrenal activity. Ten normal healthy...

  6. Cancellous bone structure of iliac crest biopsies following 370 days of head-down bed rest

    DEFF Research Database (Denmark)

    Thomsen, Jesper Skovhus; Morukov, Boris V.; Vico, Laurence

    2005-01-01

    INTRODUCTION: Static bone histomorphometry was applied to existing iliac bone sections originating from a 370-d 5 degrees head-down bed rest experiment. This bed rest experiment is the longest ever to have been conducted. We hypothesized that bed rest would decrease cancellous bone volume fractio...

  7. Effects of leg strength and bicycle ergometry exercise on cardiovascular deconditioning after 30-day head-down bed rest

    Science.gov (United States)

    Wu, Bin; Liu, Yusheng; Sun, Hongyi; Zhao, Dongming; Wang, Yue; Wu, Ping; Ni, Chengzhi

    2010-10-01

    The purpose of this study is to determine if the intermittent leg muscular strength exercise and bicycle ergometry exercise could attenuate cardiovascular deconditioning induced by prolonged -6° head-down bed rest (HDBR). Fifteen male subjects were randomly allocated into group A ( n=5, 30 days HDBR without exercise), group B ( n=5, 30 days HDBR with leg muscular strength exercise) and group C ( n=5, 30 days HDBR with bicycle ergometry exercise). The orthostatic tolerance (OT) was determined by +75°/20 min head-up tilt (HUT) test and the submaximal exercise capacity was determined by bicycle ergometry before and after HDBR. The results were as follows: (1) Compared with that before HDBR, OT time decreased dramatically by 57.6% ( pexercise time decreased significantly by 17.7% ( p0.77) in group C. (3) compared with that before HDBR, the changes of heart rate (HR) and blood pressure were slightly improved in group B and C, while deteriorated in group A during orthostatic test and exercise test after HDBR. The results indicate that leg muscular strength exercise and bicycle ergometry exercise could partially attenuate the cardiovascular deconditioning induced by 30 d HDBR, and the latter exercise training could fully provide the protection for the loss of exercise capacity.

  8. Stroke volume of the heart and thoracic fluid content during head-up and head-down tilt in humans

    DEFF Research Database (Denmark)

    van Lieshout, J J; Harms, M P M; Pott, F

    2005-01-01

    The stroke volume (SV) of the heart depends on the diastolic volume but, for the intact organism, central pressures are applied widely to express the filling of the heart.......The stroke volume (SV) of the heart depends on the diastolic volume but, for the intact organism, central pressures are applied widely to express the filling of the heart....

  9. Advances and trends of head-up and head-down display systems in automobiles

    Science.gov (United States)

    Betancur, J. Alejandro; Osorio-Gomez, Gilberto; Agudelo, J. David

    2014-06-01

    Currently, in the automotive industry the interaction between drivers and Augmented Reality (AR) systems is a subject of analysis, especially the identification of advantages and risks that this kind of interaction represents. Consequently, this paper attempts to put in evidence the potential applications of Head-Up (Display (HUD) and Head-Down Display (HDD) systems in automotive vehicles, showing applications and trends under study. In general, automotive advances related to AR devices suggest the partial integration of the HUD and HDD in automobiles; however, the right way to do it is still a moot point.

  10. Early processing variations in selective attention to the color and direction of moving stimuli during 30 days head-down bed rest

    Science.gov (United States)

    Wang, Lin-Jie; He, Si-Yang; Niu, Dong-Bin; Guo, Jian-Ping; Xu, Yun-Long; Wang, De-Sheng; Cao, Yi; Zhao, Qi; Tan, Cheng; Li, Zhi-Li; Tang, Guo-Hua; Li, Yin-Hui; Bai, Yan-Qiang

    2013-11-01

    Dynamic variations in early selective attention to the color and direction of moving stimuli were explored during a 30 days period of head-down bed rest. Event-related potentials (ERPs) were recorded at F5, F6, P5, P6 scalp locations in seven male subjects who attended to pairs of bicolored light emitting diodes that flashed sequentially to produce a perception of movement. Subjects were required to attend selectively to a critical feature of the moving target, e.g., color or direction. The tasks included: a no response task, a color selective response task, a moving direction selective response task, and a combined color-direction selective response task. Subjects were asked to perform these four tasks on: the 3rd day before bed rest; the 3rd, 15th and 30th day during the bed rest; and the 5th day after bed rest. Subjects responded quickly to the color than moving direction and combined color-direction response. And they had a longer reaction time during bed rest on the 15th and 30th day during bed rest after a relatively quicker response on the 3rd day. Using brain event-related potentials technique, we found that in the color selective response task, the mean amplitudes of P1 and N1 for target ERPs decreased in the 3rd day during bed rest and 5th day after bed rest in comparison with pre-bed rest, 15th day and 30th day during bed rest. In the combined color-direction selective response task, the P1 latencies for target ERPs on the 3rd and 30th day during bed rest were longer than on the 15th day during bed rest. As 3rd day during bed rest was in the acute adaptation period and 30th day during bed rest was in the relatively adaptation stage of head-down bed rest, the results help to clarify the effects of bed rest on different task loads and patterns of attention. It was suggested that subjects expended more time to give correct decision in the head-down tilt bed rest state. A difficulty in the recruitment of brain resources was found in feature selection task

  11. Effects of prolonged head-down bed rest on working memory

    Directory of Open Access Journals (Sweden)

    Liu Q

    2015-03-01

    Full Text Available Qing Liu,1,2 Renlai Zhou,1–4 Xin Zhao,5 Tian Po S Oei6 1Beijing Key Lab of Applied Experimental Psychology, School of Psychology, 2Research Center of Emotion Regulation, 3State Key Laboratory of Cognitive Neuroscience and Learning, International Data Group/McGovern Institute for Brain Research, Beijing Normal University, Beijing, People’s Republic of China; 4Department of Psychology, School of Social and Behavioral Science, Nanjing University, Nanjing, People’s Republic of China; 5Behavior Rehabilitation Training Research Institution, School of Psychology, Northwest Normal University, Lanzhou, People’s Republic of China; 6School of Psychology, University of Queensland, Brisbane, QLD, Australia Background: The weightlessness caused by prolonged bed rest results in changes in cerebral circulation and thus, brain functions, which is of interest. Methods: We investigated the effects of 45-day, -6° head-down bed rest, which stimulated microgravity, on working memory in 16 healthy male participants. The 2-back task was used to test the working memory variations on the 2nd day before bed rest (R-2; on the 11th (R11, 20th (R20, 32nd (R32, and 40th (R40 days of bed rest; and on the eighth day after bed rest (R+8. The cognitive response and the physiological reactivity (such as galvanic skin response, heart rate, and heart rate variability under the 2-back task were recorded simultaneously. Results: The results showed that compared with R-2, on the R+8, the participants’ galvanic skin response increased significantly, and the high frequency of heart rate variability (HF, low frequency of heart rate variability (LF, and reaction time in the 2-back task decreased significantly. There were positive correlations between the participants’ reaction time of working memory and the LF/HF under head-down bed rest (at R11, R20, and R32. Conclusion: The results suggested that the prolonged head-down bed rest may have a detrimental effect on individual

  12. [The red blood system in men during long-term head-down bed rest].

    Science.gov (United States)

    Ivanova, S M; Morukov, B V; Iarlykova, Iu V; Labetskaia, O I; Levina, A A; Kozinets, G I

    2005-01-01

    Red blood was analyzed in six 25 to 40 yr. old male volunteers in a 120-d head-down bedrest (HDBR) study. The hematological investigation included morphological analyses (erythrocyte count and hemoglobin), and determination of iron turnover, erythrocyte IgA, IgG and IgM, metabolism, lipids and phospholipids, and lipid peroxidation rate (LPO). At the beginning of HDBR (day 7), the erythrocyte count and hemoglobin content were found increased w/o any visible changes in the other parameters. Further exposure to HDBR (days 50-100) resulted in modification of intracellular metabolism in erythrocytes, increases in serum iron, and serum and erythrocyte ferritin. On HDBR days 50 and 100, and post-HDBR day 9, cholesterol was increased, LPO intensified and antioxidant activities inhibited, which suggested destabilization of the cell membrane. Hematological shifts in the bedrested volunteers were of the type and pattern similar to those in cosmonauts who fulfilled extended space missions.

  13. Hormonal changes during 17 days of head-down bed-rest

    Science.gov (United States)

    Custaud, Marc-Antoine; Arnaud, Sara B.; Monk, Timothy H.; Claustrat, Bruno; Gharib, Claude; Gauquelin-Koch, Guillemette

    2003-01-01

    We investigated in six men the impact of 17 days of head-down bed rest (HDBR) on the daily rhythms of the hormones involved in hydroelectrolytic regulation. This HDBR study was designed to mimic a real space flight. Urine samples were collected at each voiding before, during and after HDBR. Urinary excretion of Growth Hormone (GH), Cortisol, 6 Sulfatoxymelatonin, Normetadrenaline (NMN) and Metadrenaline (NM) was determined. A decrease in urinary cortisol excretion during the night of HDBR was noted. For GH, a rhythm was found before and during HDBR. The rhythm of melatonin, evaluated with the urine excretion of 6 Sulfatoxymelatonin (aMT6S), the main hepatic metabolite, persisted throughout the experiment without any modification to the level of phase. A decrease during the night was noted for normetadrenaline urinary derivates, but only during the HDBR.

  14. Positional Asphyxia: Death Due to Unusual Head-Down Position in a Narrow Space.

    Science.gov (United States)

    Chaudhari, Vinod Ashok; Ghodake, Dattatray G; Kharat, Rajesh D

    2016-06-01

    Death due to a head-down position with hyperflexion of the neck is a rare event. A person accidentally falling into a narrow space and remaining in an upside-down position with no timely recovery may experience positional or postural asphyxia. It is a critical condition arising out of particular body positions, leading to mechanical obstruction of respiration. The precipitating factors are intoxication due to alcohol, drugs, obesity, psychiatric illnesses, and injuries. A 30-year-old unmarried woman, weighing 82 kg and with a body mass index of 31.24, was found in a narrow space between the bed and the wall in a naked state and in a head-down position with hyperflexion of the neck. The distribution of lividity was consistent with the position of the body at the scene. Blood was oozing from the mouth and nostrils, and signs of asphyxia were present. The toxicological analyses of viscera, blood, and urine were negative for alcohol, drugs, and poisons. Glucose levels in the blood (86 mg/dL) as well as urine and vitreous humor levels (68 mg/dL) were within normal limits. On microscopic examination, there were no findings of coronary atherosclerosis, whereas the brain and lung were edematous. After meticulous examination, we ruled out sexual assault, autoerotic asphyxia, epilepsy, psychiatric illness, diabetes, toxicity, and coronary artery disease. Death was attributed to the accidental fall of the obese individual being stuck in a narrow space, resulting in positional asphyxia. It is imperative to recognize the precipitating or risk factors before labeling positional asphyxia as a cause of death.

  15. Head Tilt

    Science.gov (United States)

    ... Healthy Living Healthy Living Healthy Living Nutrition Fitness Sports Oral Health Emotional Wellness Growing Healthy Sleep Safety & ... When this happens, the neck muscles go into spasm, causing the head to tilt to one side. ...

  16. Acute and chronic head-down tail suspension diminishes cerebral perfusion in rats

    Science.gov (United States)

    Wilkerson, M. Keith; Colleran, Patrick N.; Delp, Michael D.

    2002-01-01

    The purpose of this study was to test the hypothesis that regional brain blood flow and vascular resistance are altered by acute and chronic head-down tail suspension (HDT). Regional cerebral blood flow, arterial pressure, heart rate, and vascular resistance were measured in a group of control rats during normal standing and following 10 min of HDT and in two other groups of rats after 7 and 28 days of HDT. Heart rate was not different among conditions, whereas mean arterial pressure was elevated at 10 min of HDT relative to the other conditions. Total brain blood flow was reduced from that during standing by 48, 24, and 27% following 10 min and 7 and 28 days of HDT, respectively. Regional blood flows to all cerebral tissues and the eyes were reduced with 10 min of HDT and remained lower in the eye, olfactory bulbs, left and right cerebrum, thalamic region, and the midbrain with 7 and 28 days of HDT. Total brain vascular resistance was 116, 44, and 38% greater following 10 min and 7 and 28 days of HDT, respectively, relative to that during control standing. Vascular resistance was elevated in all cerebral regions with 10 min of HDT and remained higher than control levels in most brain regions. These results demonstrate that HDT results in chronic elevations in total and regional cerebral vascular resistance, and this may be the underlying stimulus for the HDT-induced smooth muscle hypertrophy of cerebral resistance arteries.

  17. Effects of head-down bed rest on the executive functions and emotional response.

    Directory of Open Access Journals (Sweden)

    Qing Liu

    Full Text Available Prolonged bed rest may cause changes in the autonomic nervous system that are related to cognition and emotion. This study adopted an emotional flanker task to evaluate the effect of 45 days -6° head-down bed rest (HDBR on executive functioning in 16 healthy young men at each of six time points: the second-to-last day before the bed rest period, the eleventh, twentieth, thirty-second and fortieth day during the bed rest period, and the eighth day after the bed rest period. In addition, self-report inventories (Beck Anxiety Inventory, BAI; Beck Depression Inventory, BDI; Positive Affect and Negative Affect Scale, PANAS were conducted to record emotional changes, and the participants' galvanic skin response (GSR, heart rate (HR and heart rate variability (HRV were assessed as measures of physiological activity. The results showed that the participants' reaction time on the flanker task increased significantly relative to their responses on the second-to-last day before the period of bed rest, their galvanic skin response weakened and their degrees of positive affect declined during the bed rest period. Our results provide some evidence for a detrimental effect of prolonged bed rest on executive functioning and positive affect. Whether this stems from a lack of aerobic physical activity and/or the effect of HDBR itself remains to be determined.

  18. Changes of cytokines during a spaceflight analog--a 45-day head-down bed rest.

    Directory of Open Access Journals (Sweden)

    Xi Xu

    Full Text Available Spaceflight is associated with deregulation in the immune system. Head-down bed rest (HDBR at -6° is believed to be the most practical model for examining multi-system responses to microgravity in humans during spaceflight. In the present study, a 45-day HDBR was performed to investigate the alterations in human immune cell distributions and their functions in response to various stimuli. The effect of countermeasure, Rhodiola rosea (RR treatment, was also examined. A significant decrease of interferon-γ (IFN-γ and interleukin-17 (IL-17 productions by activated T cells, increase of IL-1β and IL-18 by activated B and myeloid cells were observed during HDBR. The upregulation of serum cortisol was correlated with the changes of IL-1 family cytokines. In addition, a significant increase of memory T and B cell and regulatory T cells (Treg were also detected. The uptake of RR further decreased IFN-γ level and slowed down the upregulation of IL-1 family cytokines. These data suggest that for prolonged HDBR and spaceflight, the decreased protective T cell immunity and enhanced proinflammatory cytokines should be closely monitored. The treatment with RR may play an important role in suppressing proinflammatory cytokines but not in boosting protective T cell immunity.

  19. Cardiovascular Responses during Head-Down Crooked Kneeling Position Assumed in Muslim Prayers

    Directory of Open Access Journals (Sweden)

    Adamu Ahmad Rufa’i

    2013-06-01

    Full Text Available Background: Movement dysfunction may be expressed in terms of symptoms experienced in non-physiological postures, and head-down crooked kneeling (HDCK is a posture frequently assumed by Muslims during prayer activities. The purpose of this study was to investigate the cardiovascular responses in the HDCK posture. Methods: Seventy healthy volunteers, comprising 35 males and 35 females, participated in the study. Cardiovascular parameters of blood pressure and pulse rate of the participants were measured in rested sitting position and then at one and three minutes into the HDCK posture. Two-way ANOVA was used to determine the differences between cardiovascular responses at rest and in the HDCK posture, and the Student t test was utilized to determine gender difference in cardiovascular responses at rest and at one and three minutes into the HDCK posture. Results: The study showed a significant decrease in systolic and diastolic blood pressures at one minute into the HDCK posture and an increase in pulse rate at one and three minutes into the HDCK posture, as compared to the resting values. Rate pressure product also rose at one minute into the HDCK posture, whereas pulse pressure increased at one and three minutes into the HDCK posture, as compared with the resting values. However, no significant change was observed in the mean arterial pressure values. Conclusion: The findings from this study suggest that no adverse cardiovascular event can be expected to occur for the normal duration of this posture during Muslim prayer activities.

  20. Cardiovascular Responses during Head-Down Crooked Kneeling Position Assumed in Muslim Prayers

    Science.gov (United States)

    Ahmad Rufa’i, Adamu; Hamu Aliyu, Hadeezah; Yunoos Oyeyemi, Adetoyeje; Lukman Oyeyemi, Adewale

    2013-01-01

    Background: Movement dysfunction may be expressed in terms of symptoms experienced in non-physiological postures, and head-down crooked kneeling (HDCK) is a posture frequently assumed by Muslims during prayer activities. The purpose of this study was to investigate the cardiovascular responses in the HDCK posture. Methods: Seventy healthy volunteers, comprising 35 males and 35 females, participated in the study. Cardiovascular parameters of blood pressure and pulse rate of the participants were measured in rested sitting position and then at one and three minutes into the HDCK posture. Two-way ANOVA was used to determine the differences between cardiovascular responses at rest and in the HDCK posture, and the Student t test was utilized to determine gender difference in cardiovascular responses at rest and at one and three minutes into the HDCK posture. Results: The study showed a significant decrease in systolic and diastolic blood pressures at one minute into the HDCK posture and an increase in pulse rate at one and three minutes into the HDCK posture, as compared to the resting values. Rate pressure product also rose at one minute into the HDCK posture, whereas pulse pressure increased at one and three minutes into the HDCK posture, as compared with the resting values. However, no significant change was observed in the mean arterial pressure values. Conclusion: The findings from this study suggest that no adverse cardiovascular event can be expected to occur for the normal duration of this posture during Muslim prayer activities. PMID:24031108

  1. Caloric restriction decreases orthostatic tolerance independently from 6° head-down bedrest.

    Directory of Open Access Journals (Sweden)

    John P Florian

    Full Text Available Astronauts consume fewer calories during spaceflight and return to earth with an increased risk of orthostatic intolerance. Whether a caloric deficiency modifies orthostatic responses is not understood. Thus, we determined the effects of a hypocaloric diet (25% caloric restriction during 6° head down bedrest (an analog of spaceflight on autonomic neural control during lower body negative pressure (LBNP. Nine healthy young men completed a randomized crossover bedrest study, consisting of four (2 weeks each interventions (normocaloric bedrest, normocaloric ambulatory, hypocaloric bedrest, hypocaloric ambulatory, each separated by 5 months. Muscle sympathetic nerve activity (MSNA was recorded at baseline following normocaloric and hypocaloric interventions. Heart rate (HR and arterial pressure were recorded before, during, and after 3 consecutive stages (7 min each of LBNP (-15, -30, -45 mmHg. Caloric and posture effects during LBNP were compared using two-way ANOVA with repeated measures. There was a strong trend toward reduced basal MSNA following caloric restriction alone (normcaloric vs. hypocaloric: 22±3 vs. 14±4 burst/min, p = 0.06. Compared to the normocaloric ambulatory, both bedrest and caloric restriction were associated with lower systolic blood pressure during LBNP (p<0.01; however, HR responses were directionally opposite (i.e., increase with bedrest, decrease with caloric restriction. Survival analysis revealed a significant reduction in orthostatic tolerance following caloric restriction (normocaloric finishers: 12/16; hypocaloric finishers: 6/16; χ2, p = 0.03. Caloric restriction modifies autonomic responses to LBNP, which may decrease orthostatic tolerance after spaceflight.

  2. Velocity dependence of vestibular information for postural control on tilting surfaces.

    Science.gov (United States)

    Horak, Fay B; Kluzik, JoAnn; Hlavacka, Frantisek

    2016-09-01

    Vestibular information is known to be important for postural stability on tilting surfaces, but the relative importance of vestibular information across a wide range of surface tilt velocities is less clear. We compared how tilt velocity influences postural orientation and stability in nine subjects with bilateral vestibular loss and nine age-matched, control subjects. Subjects stood on a force platform that tilted 6 deg, toes-up at eight velocities (0.25 to 32 deg/s), with and without vision. Results showed that visual information effectively compensated for lack of vestibular information at all tilt velocities. However, with eyes closed, subjects with vestibular loss were most unstable within a critical tilt velocity range of 2 to 8 deg/s. Subjects with vestibular deficiency lost their balance in more than 90% of trials during the 4 deg/s condition, but never fell during slower tilts (0.25-1 deg/s) and fell only very rarely during faster tilts (16-32 deg/s). At the critical velocity range in which falls occurred, the body center of mass stayed aligned with respect to the surface, onset of ankle dorsiflexion was delayed, and there was delayed or absent gastrocnemius inhibition, suggesting that subjects were attempting to actively align their upper bodies with respect to the moving surface instead of to gravity. Vestibular information may be critical for stability at velocities of 2 to 8 deg/s because postural sway above 2 deg/s may be too fast to elicit stabilizing responses through the graviceptive somatosensory system, and postural sway below 8 deg/s may be too slow for somatosensory-triggered responses or passive stabilization from trunk inertia.

  3. Head-down bed rest reduces the breathing rate short-term variability in subjects with orthostatic intolerance.

    Science.gov (United States)

    Balocchi, R; Menicucci, D; Varanini, M; Chillemi, S; Legramante, J M; Saltini, C; Raimondi, G

    2004-07-01

    Orthostatic intolerance is the most serious symptom of cardiovascular deconditioning induced by microgravity. We have showed that in symptomatic subjects the baroreflex control of sinus node is affected by short term simulated microgravity. At present the influence of the respiration on the cardiovascular system in this condition is not clear. The aim of the present study was to examine the behaviour of the Breathing Rate (BR) in 5 Non-Symptomatic (NS) and 3 Symptomatic (S) subjects before and after 4 hours of head-down bed rest (HD).

  4. Tilting Saturn without tilting Jupiter: Constraints on giant planet migration

    CERN Document Server

    Brasser, R

    2015-01-01

    The migration and encounter histories of the giant planets in our Solar System can be constrained by the obliquities of Jupiter and Saturn. We have performed secular simulations with imposed migration and N-body simulations with planetesimals to study the expected obliquity distribution of migrating planets with initial conditions resembling those of the smooth migration model, the resonant Nice model and two models with five giant planets initially in resonance (one compact and one loose configuration). For smooth migration, the secular spin-orbit resonance mechanism can tilt Saturn's spin axis to the current obliquity if the product of the migration time scale and the orbital inclinations is sufficiently large (exceeding 30 Myr deg). For the resonant Nice model with imposed migration, it is difficult to reproduce today's obliquity values, because the compactness of the initial system raises the frequency that tilts Saturn above the spin precession frequency of Jupiter, causing a Jupiter spin-orbit resonance...

  5. Decreasing ventromedial prefrontal cortex deactivation in risky decision making after simulated microgravity: Effects of -6 degree head-down tilt bed rest

    Directory of Open Access Journals (Sweden)

    Li-Lin eRao

    2014-05-01

    Full Text Available Space is characterized by risk and uncertainty. As humans play an important role in long-duration space missions, the ability to make risky decisions effectively is important for astronauts who spend extended time periods in space. The present study used the Balloon Analog Risk Task to conduct both behavioral and fMRI experiments to evaluate the effects of simulated microgravity on individuals’ risk-taking behavior and the neural basis of the effect. The results showed that participants’ risk-taking behavior was not affected by bed rest. However, we found that the ventromedial prefrontal cortex (VMPFC showed less deactivation after bed rest and that the VMPFC activation in the active choice condition showed no significant difference between the win outcome and the loss outcome after bed rest, although its activation was significantly greater in the win outcome than in the loss outcome before bed rest. These results suggested that the participants showed a decreased level of value calculation after the bed rest. Our findings can contribute to a better understanding of the effect of microgravity on individual higher-level cognitive functioning.

  6. A combination of whey protein and potassium bicarbonate supplements during head-down-tilt bed rest: Presentation of a multidisciplinary randomized controlled trial (MEP study)

    Science.gov (United States)

    Buehlmeier, Judith; Mulder, Edwin; Noppe, Alexandra; Frings-Meuthen, Petra; Angerer, Oliver; Rudwill, Floriane; Biolo, Gianni; Smith, Scott M.; Blanc, Stéphane; Heer, Martina

    2014-02-01

    Inactivity, as it appears during space flight and in bed rest, induces reduction of lean body and bone mass, glucose intolerance, and weakening of the cardiovascular system. Increased protein intake, whey protein in particular, has been proposed to counteract some of these effects, but has also been associated with negative effects on bone, likely caused by a correspondingly high ratio of acid to alkali precursors in the diet.

  7. No effect of artificial gravity on lung function with exercise training during head-down bed rest

    Science.gov (United States)

    Su, Longxiang; Guo, Yinghua; Wang, Yajuan; Wang, Delong; Liu, Changting

    2016-04-01

    The aim of this study is to explore the effectiveness of microgravity simulated by head-down bed rest (HDBR) and artificial gravity (AG) with exercise on lung function. Twenty-four volunteers were randomly divided into control and exercise countermeasure (CM) groups for 96 h of 6° HDBR. Comparisons of pulse rate, pulse oxygen saturation (SpO2) and lung function were made between these two groups at 0, 24, 48, 72, 96 h. Compared with the sitting position, inspiratory capacity and respiratory reserve volume were significantly higher than before HDBR (0° position) (P control nor CM groups showed significant differences in pulse rate, SpO2, pulmonary volume and pulmonary ventilation function over the HDBR observation time. Postural changes can lead to variation in lung volume and ventilation function, but a HDBR model induced no changes in pulmonary function and therefore should not be used to study AG countermeasures.

  8. Effect of head-down bed rest on the neuroendocrine response to orthostatic stress in physically fit men.

    Science.gov (United States)

    Koska, J; Ksinantová, L; Kvetnanský, R; Marko, M; Hamar, D; Vigas, M; Hatala, R

    2003-01-01

    The role of neuroendocrine responsiveness in the development of orthostatic intolerance after bed rest was studied in physically fit subjects. Head-down bed-rest (HDBR, -6 degrees, 4 days) was performed in 15 men after 6 weeks of aerobic training. The standing test was performed before, after training and on day 4 of the HDBR. Orthostatic intolerance was observed in one subject before and after training. The blood pressure response after training was enhanced (mean BP increments 18+/-2 vs. 13+/- 2 mm Hg, pE.M.), although noradrenaline response was diminished (1.38+/-0.18 vs. 2.76+/-0.25 mol.l(-1), pstanding and had no effect on the orthostatic tolerance. In orthostatic intolerance the BP response induced by subsequent HDBR was absent despite an enhanced sympathetic response.

  9. Il teatro degli spiriti.

    Directory of Open Access Journals (Sweden)

    Chiara Pussetti

    2013-07-01

    Full Text Available Questo saggio è dedicato a un culto di possessione, in cui tutte ledonne, investite dagli spiriti degli uomini morti prima dell’iniziazione, compiono un percorso iniziatico parallelo a quello maschile, consentendo a queste anime, potenzialmente pericolose, di completare il cammino che non hanno potuto percorrere da vivi e quindi di raggiungere serenamente il mondo dei morti, come antenati protettori del villaggio

  10. Effect of 21-day head down bed rest on urine proteins related to endothelium: Correlations with changes in carbohydrate metabolism

    Science.gov (United States)

    Kashirina, D.; Pastushkova, L.; Custaud, M. A.; Dobrokhotov, I.; Brzhozovsky, A.; Navasiolava, N.; Nosovsky, A.; Kononikhin, A.; Nikolaev, E.; Larina, I.

    2017-08-01

    We performed liquid chromatography-mass spectrometric study of the urine proteome in 8 healthy volunteers aged between 20 and 44 y.o. who have completed 21-day head-down bed rest. ANDSystem software which builds associative networks was used to identify the urinary proteins functionally related to the endothelium. We identified 7 endothelium-related biological processes, directly linked to 13 urine proteins. We performed manual annotation of the proteins which were the most important in terms of endothelial functions. Analysis of the correlations with biochemical variables revealed a positive correlation between fasting blood glucose and the following urine proteins: albumin, CD44 antigen, endothelial protein C receptor, mucin-1, osteopontin, receptor tyrosine kinase. As well, we found a positive correlation between HOMA-insulin resistance index and the following urine proteins: endothelial protein C receptor and syndecan-4. These results might suggest the involvement of above-mentioned proteins in glucose metabolism and their participation in the response to changes in blood glucose level.

  11. Effects of encouraged water drinking on thermoregulatory responses after 20 days of head-down bed rest in humans

    Science.gov (United States)

    Sato, Maki; Kanikowska, Dominika; Iwase, Satoshi; Shimizu, Yuuki; Inukai, Yoko; Nishimura, Naoki; Sugenoya, Junichi

    2009-09-01

    We tested the hypothesis that encouraged water drinking according to urine output for 20 days could ameliorate impaired thermoregulatory function under microgravity conditions. Twelve healthy men, aged 24 ± 1.5 years (mean ± SE), underwent -6° head-down bed rest (HDBR) for 20 days. During bed rest, subjects were encouraged to drink the same amount of water as the 24-h urine output volume of the previous day. A heat exposure test consisting of water immersion up to the knees at 42°C for 45 min after a 10 min rest (baseline) in the sitting position was performed 2 days before the 20-day HDBR (PRE), and 2 days after the 20-day HDBR (POST). Core temperature (tympanic), skin temperature, skin blood flow and sweat rate were recorded continuously. We found that the -6° HDBR did not increase the threshold temperature for onset of sweating under the encouraged water drinking regime. We conclude that encouraged water drinking could prevent impaired thermoregulatory responses after HDBR.

  12. Effects of prolonged head-down bed rest with and without fly-wheel exercise on heart rate variability

    Science.gov (United States)

    Pavy-Le Traon, Anne; Curnier, Daniel; Bernard, Jacques; Beroud, Stephane; Costes-Salon, Marie-Claude; Bareille, Marie-Pierre; Pathak, Atul; Galinier, Michel

    2005-08-01

    The aim of this study was to investigate the effects of prolonged Head down bed rest (HDBR) (90 days) on heart rate variability (HRV) in 25 healthy male volunteers (mean age: 33 y). Nine subjects performed flywheel resistance muscular training. 24h-ECG recordings were performed in pre- HDBR (D-12, D-3), HDBR (D 15, D 32, D 62, D 85) and recovery (D+4). The mean HR, SDNN and coefficient of variation (SDNN normalized by HR) reflecting overall HRV were calculated as well as the power in Low (LF) and High (HF) frequencies (24h- period). HDBR induced a significant decrease in HRV favoured by inactivity. LF and LF/HF mainly under sympathetic influence decreased significantly on D15 and then tended to stabilise around baseline values. HF reflecting parasympathetic modulation decreased with HDBR but some changes occurred in pre-HDBR, in relation with the experiment conditions, and raised the issue of reference values. No exercise effect was observed.

  13. Electromyography-based analysis of human upper limbs during 45-day head-down bed-rest

    Science.gov (United States)

    Fu, Anshuang; Wang, Chunhui; Qi, Hongzhi; Li, Fan; Wang, Zheng; He, Feng; Zhou, Peng; Chen, Shanguang; Ming, Dong

    2016-03-01

    Muscle deconditioning occurs in response to simulated or actual microgravity. In spaceflight, astronauts become monkey-like for mainly using their upper limbs to control the operating system and to complete corresponding tasks. The changes of upper limbs' athletic ability will directly affect astronauts' working performance. This study investigated the variation trend of surface electromyography (sEMG) during prolonged simulated microgravity. Eight healthy males participating in this study performed strict 45-day head-down bed-rest (HDBR). On the 5th day of pre-HDBR, and the 15th, the 30th and the 45th days of HDBR, the subjects performed maximum pushing task and maximum pulling task, and sEMG was collected from upper limbs synchronously. Each subject's maximum volunteer contractions of both the tasks during these days were compared, showing no significant change. However, changes were detected by sEMG-based analysis. It was found that integrated EMG, root mean square, mean frequency, fuzzy entropy of deltoid, and fuzzy entropy of triceps brachii changed significantly when comparing pre-HDBR with HDBR. The variation trend showed a recovery tendency after significant decline, which is inconsistent with the monotonic variation of lower limbs that was proved by previous research. These findings suggest that EMG changes in upper limbs during prolonged simulated microgravity, but has different variation trend from lower limbs.

  14. Ingegneria degli acquiferi

    CERN Document Server

    Molfetta, Antonio

    2012-01-01

    Il testo fornisce le conoscenze necessarie per affrontare, con un approccio quantitativo, i molteplici aspetti connessi al flusso delle risorse idriche sotterranee (acque di falda) e alla propagazione e bonifica di contaminanti nei sistemi acquiferi. Vengono illustrate le proprietà fondamentali che definiscono la capacità di immagazzinamento, trasporto e rilascio dell’acqua negli acquiferi, e successivamente, descritte le metodiche per la determinazione di tali parametri tramite l’esecuzione e l’interpretazione di prove di falda, di pozzo e di laboratorio. A partire dalla classificazione chimico fisica-tossicologica dei contaminanti vengono, quindi, analizzati i meccanismi di propagazione e illustrate le soluzioni analitiche dell’equazione del trasporto di massa nei mezzi porosi. L’ultima parte del testo è dedicata alla caratterizzazione e bonifica degli acquiferi contaminati. Il testo è rivolto sia agli studenti universitari, sia ai professionisti che debbano affrontare con un approccio quantit...

  15. Atrial natriuretic peptide contribution to lipid mobilization and utilization during head-down bed rest in humans.

    Science.gov (United States)

    Moro, Cédric; Pillard, Fabien; de Glisezinski, Isabelle; Crampes, Francois; Thalamas, Claire; Harant, Isabelle; Marques, Marie-Adeline; Lafontan, Max; Berlan, Michel

    2007-08-01

    Head-down bed rest (HDBR) increases plasma levels of atrial natriuretic peptide (ANP) and decreases norepinephrine levels. We previously demonstrated that ANP promotes lipid mobilization and utilization, an effect independent of sympathetic nervous system activation, when infused into lean healthy men at pharmacological doses. The purpose of the present study was to demonstrate that a physiological increase in ANP contributes to lipid mobilization and oxidation in healthy young men. Eight men were positioned for 4 h in a sitting (control) or in a HDBR position. Indexes of lipid mobilization and hormonal changes were measured in plasma. Extracellular glycerol, an index of lipolysis, was determined in subcutaneous adipose tissue (SCAT) with a microdialysis technique. A twofold increase in plasma ANP concentration was observed after 60 min of HDBR, and a plateau was maintained thereafter. Plasma norepinephrine decreased by 30-40% during HDBR, while plasma insulin and glucose levels did not change. The level of plasma nonesterified fatty acids was higher during HDBR. SCAT lipolysis, as reflected by interstitial glycerol, as well as interstitial cGMP, the second messenger of the ANP pathway, increased during HDBR. This was associated with an increase in blood flow observed throughout HDBR. Significant changes in respiratory exchange ratio and percent use of lipid and carbohydrate were seen only after 3 h of HDBR. Thus the proportion of lipid oxidized increased by 40% after 3 h of HDBR. The rise in plasma ANP during HDBR was associated with increased lipolysis in SCAT and whole body lipid oxidation. In this physiological setting, independent of increasing catecholamines, our study suggests that ANP contributes to lipid mobilization and oxidation in healthy young men.

  16. Increase in epinephrine-induced responsiveness during microgravity simulated by head-down bed rest in humans.

    Science.gov (United States)

    Barbe, P; Galitzky, J; Thalamas, C; Langin, D; Lafontan, M; Senard, J M; Berlan, M

    1999-11-01

    The epinephrine (Epi)-induced effects on the sympathetic nervous system (SNS) and metabolic functions were studied in men before and during a decrease in SNS activity achieved through simulated microgravity. Epi was infused at 3 graded rates (0.01, 0.02, and 0. 03 microg. kg(-1). min(-1) for 40 min each) before and on the fifth day of head-down bed rest (HDBR). The effects of Epi on the SNS (assessed by plasma norepinephrine levels and spectral analysis of systolic blood pressure and heart rate variability), on plasma levels of glycerol, nonesterified fatty acids (NEFA), glucose and insulin, and on energy expenditure were evaluated. HDBR decreased urinary norepinephrine excretion (28.1 +/- 4.2 vs. 51.5 +/- 9.1 microg/24 h) and spectral variability of systolic blood pressure in the midfrequency range (16.3 +/- 1.9 vs. 24.5 +/- 0.9 normalized units). Epi increased norepinephrine plasma levels (P < 0.01) and spectral variability of systolic blood pressure (P < 0.009) during, but not before, HDBR. No modification of Epi-induced changes in heart rate and systolic and diastolic blood pressures were observed during HDBR. Epi increased plasma glucose, insulin, and NEFA levels before and during HDBR. During HDBR, the Epi-induced increase in plasma glycerol and lactate levels was more pronounced than before HDBR (P < 0.005 and P < 0.001, respectively). Epi-induced energy expenditure was higher during HDBR (P < 0.02). Our data suggest that the increased effects of Epi during simulated microgravity could be related to both the increased SNS response to Epi infusion and/or to the beta-adrenergic receptor sensitization of end organs, particularly in adipose tissue and skeletal muscle.

  17. Effect of space flight and head-down bedrest on neuroendocrine response to metabolic stress in physically trained subjects.

    Science.gov (United States)

    Kvetnanský, R; Ksinantová, L; Koska, J; Noskov, V B; Vigas, M; Grigoriev, A I; Macho, L

    2004-07-01

    The aim of this study was to evaluate the association of plasma epinephrine (EPI) and norepinephrine (NE) responses to insulin induced hypoglycemia (ITT) 3 weeks before the space flight (SF), on the 5th day of SF, on the 2nd and 16th days after the landing in the first Slovak astronaut, and before and on the 5th day of prolonged subsequent head-down (-6 degrees) bed rest (BR) in 15 military aircraft pilots. Blood samples during the test were collected via cannula inserted into cubital vein, centrifuged in the special appliance Plasma-03, frozen in Kryogem-03, and at the end of the 8-day space flight transferred to Earth in special container for hormonal analysis. Insulin hypoglycemia was induced by i.v. administration of 0.1 IU/kg BW insulin (Actrapid HM) in bolus. Insulin administration led to a comparable hypoglycemia in pre-flight, in-flight conditions and before and after bed rest. ITT led to a pronounced increase in EPI levels and moderate increase in NE in pre-flight studies. However, an evidently reduced EPI response was found after insulin administration during SF and during BR. Thus, during the real microgravity in SF and simulated microgravity in BR, insulin-induced hypoglycemia activates the adrenomedullary system to less extent than at conditions of the Earth gravitation. Post-flight changes in EPI and NE levels did not significantly differ from those of pre-flight since SF was relatively short (8 days) and the readaptation to Earth gravitation was fast. It seems, that an increased blood flow in brain might be responsible for the reduced EPI response to insulin. Responses to ITT in physically fit subjects indicate the stimulus specificity of deconditioning effect of 5 days bed rest on stress response. Thus, the data indicate that catecholamine responses to ITT are reduced after exposure to real as well as simulated microgravity.

  18. Gender differences in endocrine responses to posture and 7 days of -6 degrees head-down bed rest

    Science.gov (United States)

    Vernikos, J.; Dallman, M. F.; Keil, L. C.; O'Hara, D.; Convertino, V. A.

    1993-01-01

    Endocrine regulation of fluids and electrolytes during 7 days of -6 degrees head-down bed rest (HDBR) was compared in male (n = 8) and, for the first time, female (n = 8) volunteers. The subjects' responses to quiet standing for 2 h before and after HDBR were also tested. In both sexes, diuresis and natriuresis were evident during the first 2-3 days of HDBR, resulting in a marked increase in the urinary Na(+)-to-K+ ratio and significant Na+ retention on re-ambulation. After the 1st day of HDBR, plasma renin activity (PRA) was increased relative to aldosterone (Aldo), plasma volume was decreased, and the renal response to Aldo appeared to be appropriate. Circulating levels of arginine vasopressin, cortisol, and ACTH were unchanged during HDBR. Plasma testosterone decreased slightly on day 2 of HDBR in males. The ratio of early morning ACTH to cortisol was lower in females than in males because ACTH was lower in females. Urinary cortisol increased and remained elevated throughout the HDBR in males only. There were no gender differences in the responses to 7 days of HDBR, except those in the pituitary-adrenal system; those differences appeared unrelated to the postural change. The provocative cardiovascular test of quiet standing before and after HDBR revealed both sex differences and effects of HDBR. There were significant sex differences in cardiovascular responses to standing before and after HDBR. Females had greater PRA and Aldo responses to standing before HDBR and larger Aldo responses to standing after HDBR than males.(ABSTRACT TRUNCATED AT 250 WORDS).

  19. Gravito-Inertial Force Resolution in Perception of Synchronized Tilt and Translation

    Science.gov (United States)

    Wood, Scott J.; Holly, Jan; Zhang, Guen-Lu

    2011-01-01

    Natural movements in the sagittal plane involve pitch tilt relative to gravity combined with translation motion. The Gravito-Inertial Force (GIF) resolution hypothesis states that the resultant force on the body is perceptually resolved into tilt and translation consistently with the laws of physics. The purpose of this study was to test this hypothesis for human perception during combined tilt and translation motion. EXPERIMENTAL METHODS: Twelve subjects provided verbal reports during 0.3 Hz motion in the dark with 4 types of tilt and/or translation motion: 1) pitch tilt about an interaural axis at +/-10deg or +/-20deg, 2) fore-aft translation with acceleration equivalent to +/-10deg or +/-20deg, 3) combined "in phase" tilt and translation motion resulting in acceleration equivalent to +/-20deg, and 4) "out of phase" tilt and translation motion that maintained the resultant gravito-inertial force aligned with the longitudinal body axis. The amplitude of perceived pitch tilt and translation at the head were obtained during separate trials. MODELING METHODS: Three-dimensional mathematical modeling was performed to test the GIF-resolution hypothesis using a dynamical model. The model encoded GIF-resolution using the standard vector equation, and used an internal model of motion parameters, including gravity. Differential equations conveyed time-varying predictions. The six motion profiles were tested, resulting in predicted perceived amplitude of tilt and translation for each. RESULTS: The modeling results exhibited the same pattern as the experimental results. Most importantly, both modeling and experimental results showed greater perceived tilt during the "in phase" profile than the "out of phase" profile, and greater perceived tilt during combined "in phase" motion than during pure tilt of the same amplitude. However, the model did not predict as much perceived translation as reported by subjects during pure tilt. CONCLUSION: Human perception is consistent with

  20. Effect of centrifuge-induced artificial gravity and ergometric exercise on cardiovascular deconditioning, myatrophy, and osteoporosis induced by a -6 degrees head-down bedrest.

    Science.gov (United States)

    Iwase, Satoshi; Takada, Hiroki; Watanabe, Yoriko; Ishida, Koji; Akima, Hiroshi; Katayama, Keisho; Iwase, Mitsunori; Hirayanagi, Kaname; Shiozawa, Tomoki; Hamaoka, Takafumi; Masuo, Yoshihisa; Custaud, Marc-Antoine

    2004-07-01

    We have reported that centrifuge-induced artificial gravity with ergometric exercise could reduce developing cardiovascular deconditioning in humans. In the present study, we examined this load could prevent the myatrophy and osteoporosis induced by head-down bedrest for 20 days. Subjects were ten healthy male volunteers with informed consent. They were requested to lie down at -6 degrees for 20 days, and evaluation for cardiovascular deconditioning, myatrophy, and osteoporosis. As the result, high G-load with low intensity exercise suppressed the orthostatic intolerance and increase in serum osteoporotic marker, whereas low G-load with high intensity ergometric exercise maintained the maximal oxygen intake, heart dimension, and prevented myatrophy. The combination of high/low G-load with low/high intensity exercise will determine the optimal protocol for prevention of cardiovascular deconditioning, myatrophy, and osteoporosis.

  1. Vehicle with tilting suspension system

    OpenAIRE

    Festini, Andrea; Tonoli, Andrea; Cavalli, Fabio; Carabelli, Stefano

    2006-01-01

    The patent is relative to the application of a tilting suspension on a snowmobile to improve its drive feeling and safety. At high speed the introduction of the tilting suspension reduce the rollover risk during cornering. The vehicle can tilt as a motorcycle and its lateral dimensions can be reduced not compromising the vehicle stability

  2. Re-examining Sunspot Tilt Angle to Include Anti-Hale Statistics

    CERN Document Server

    McClintock, Bruce H; Li, Jing

    2014-01-01

    Sunspot groups and bipolar magnetic regions (BMRs) serve as an observational diagnostic of the solar cycle. We use Debrecen Photohelographic Data (DPD) from 1974-2014 that determined sunspot tilt angles from daily white light observations, and data provided by Li & Ulrich that determined sunspot magnetic tilt angle using Mount Wilson magnetograms from 1974-2012. The magnetograms allowed for BMR tilt angles that were anti-Hale in configuration, so tilt values ranged from 0 to 360{\\deg} rather than the more common $\\pm$ 90{\\deg}. We explore the visual representation of magnetic tilt angles on a traditional butterfly diagram by plotting the mean area-weighted latitude of umbral activity in each bipolar sunspot group, including tilt information. The large scatter of tilt angles over the course of a single cycle and hemisphere prevents Joy's law from being visually identified in the tilt-butterfly diagram without further binning. The average latitude of anti-Hale regions does not differ from the average latitu...

  3. Motion Perception and Manual Control Performance During Passive Tilt and Translation Following Space Flight

    Science.gov (United States)

    Clement, Gilles; Wood, Scott J.

    2010-01-01

    This joint ESA-NASA study is examining changes in motion perception following Space Shuttle 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 has been collected on 5 astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation (216 deg/s) combined with body translation (12-22 cm, peak-to-peak) is utilized to elicit roll-tilt perception (equivalent to 20 deg, peak-to-peak). A forward-backward moving sled (24-390 cm, peak-to-peak) with or without chair tilting in pitch is utilized to elicit pitch tilt perception (equivalent to 20 deg, peak-to-peak). These combinations are elicited at 0.15, 0.3, and 0.6 Hz for evaluating the effect of motion frequency on tilt-translation ambiguity. In both devices, a closed-loop nulling task is also performed during pseudorandom motion with and without vibrotactile feedback of tilt. All tests are performed in complete darkness. PRELIMINARY RESULTS. Data collection is currently ongoing. Results to date suggest there is a trend for translation motion perception to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. DISCUSSION. The results of this study indicate that post-flight recovery of motion perception and manual control performance is complete within 8 days following short-duration space missions. Vibrotactile feedback of tilt improves manual control performance both before and after flight.

  4. Tilted string cosmologies

    Science.gov (United States)

    Clancy, Dominic; Feinstein, Alexander; Lidsey, James E.; Tavakol, Reza

    1999-04-01

    Global symmetries of the string effective action are employed to generate tilted, homogeneous Bianchi type VIh string cosmologies from a previously known stiff perfect fluid solution to Einstein gravity. The dilaton field is not constant on the surfaces of homogeneity. The future asymptotic state of the models is interpreted as a plane wave and is itself an exact solution to the string equations of motion to all orders in the inverse string tension. An inhomogeneous generalization of the Bianchi type III model is also found.

  5. Rigidity of tilting modules

    DEFF Research Database (Denmark)

    Let $U_q$ denote the quantum group associated with a finite dimensional semisimple Lie algebra. Assume that $q$ is a complex root of unity of odd order and that $U_q$ is %the quantum group version obtained via Lusztig's $q$-divided powers construction. We prove that all regular projective (tilting......$ and in this case as well as for type $A_2$ we calculate explicitly the Loewy structure for all regular Weyl modules. We also demonstrate that these results carry over to the modular case when the highest weights in question are in the so-called Jantzen region. At the same time we show by examples that as soon...

  6. Effects of Vestibular Loss on Orthostatic Responses to Tilts in the Pitch Plane

    Science.gov (United States)

    Wood, Scott J.; Serrador, Jorge M.; Black, F. Owen; Rupert,Angus H.; Schlegel, Todd T.

    2004-01-01

    The purpose of this study was to determine the extent to which vestibular loss might impair orthostatic responses to passive tilts in the pitch plane in human subjects. Data were obtained from six subjects having chronic bilateral vestibular loss and six healthy individuals matched for age, gender, and body mass index. Vestibular loss was assessed with a comprehensive battery including dynamic posturography, vestibulo-ocular and optokinetic reflexes, vestibular evoked myogenic potentials, and ocular counterrolling. Head up tilt tests were conducted using a motorized two-axis table that allowed subjects to be tilted in the pitch plane from either a supine or prone body orientation at a slow rate (8 deg/s). The sessions consisted of three tilts, each consisting of20 min rest in a horizontal position, tilt to 80 deg upright for 10 min, and then return to the horizontal position for 5 min. The tilts were performed in darkness (supine and prone) or in light (supine only). Background music was used to mask auditory orientation cues. Autonomic measurements included beat-to-beat recordings of blood pressure (Finapres), heart rate (ECG), cerebral blood flow velocity in the middle cerebral artery (transcranial Doppler), end tidal CO2, respiratory rate and volume (Respritrace), and stroke volume (impedance cardiography). For both patients and control subjects, cerebral blood flow appeared to exhibit the most rapid adjustment following transient changes in posture. Outside of a greater cerebral hypoperfusion in patients during the later stages of tilt, responses did not differ dramatically between the vestibular loss and control subjects, or between tilts performed in light and dark room conditions. Thus, with the 'exception of cerebrovascular regulation, we conclude that orthostatic responses during slow postural tilts are not substantially impaired in humans following chronic loss of vestibular function, a result that might reflect compensation by nonvisual graviceptor

  7. Cloning and sequencing the degS-degU operon from an alkalophilic Bacillus-brevis

    CSIR Research Space (South Africa)

    Louw, M

    1994-10-01

    Full Text Available at the amino acid level to the B. subtilis degS-degU genes showed 74% and 84% similarity, respectively. On a multicopy vector the B. brevis degS-degU genes were found to cause hypersecretion of several extracellular enzymes in a B. subtilis rec (-) strain...

  8. Color Head Down Display Program

    Science.gov (United States)

    1993-04-01

    fabricate the trasistor armay is described below. "The pr cess flow for the fabrication of the 400 x 800 trasistor army is shown in Fig 8. The...CHARACTERISTCS The x-Si .aray fabrication and circuit transfer processes were evaluated based on the electrical charcterstics of n- and p- channel trasistors

  9. 头低位卧床期间人体肠道益生菌多样性变化%Observation of microbe diversity and dynamic changes of intestinal probiotic bacteria during head-down tilt bed rest

    Institute of Scientific and Technical Information of China (English)

    雷浪伟; 韩炳星; 兰海云; 张淑静; 陈斌

    2015-01-01

    目的 观察了解头低位卧床期间人体肠道益生菌双歧杆菌属、乳酸杆菌属的数量及多样性的变化趋势.方法 采集受试者-6°头低位连续卧床30 d期间肠道便样,通过平板可培养技术、浓度梯度凝胶电泳技术和Ion Torrent基因组测序技术平台等实验方法,检测分析肠道粪便益生菌.结果 卧床期间,可培养肠道菌群中的双歧杆菌、乳杆菌数量显著减少,益生菌中双歧杆菌出现不规律的缺失与恢复,肠道菌群多样性指数下降.结论 头低位卧床期间肠道益生菌多样性发生了改变.益生菌数量减少,多样性指数下降,头低位卧床对肠道菌群有不利的影响.

  10. Changes in the arteriolar volume pulse of the finger during various degrees of tilt using near infra-red and red photoplethysmography.

    Science.gov (United States)

    Christ, F; Nehring, I; Abicht, J; Baranov, V; Kotov, A; Gartside, I; Gamble, J; Messmer, K

    1998-05-12

    1. Photoplethysmography is a widely used non invasive technique for the measurement of peripheral oxygen saturation. A more detailed analysis of the volume pulse (VP) can indicate alterations in peripheral vascular tone, due to sympathetic stimulation, stress, pain and temperature. - 2. In six healthy male volunteers we investigated changes in the VP resulting from vasoconstriction and vasodilatation induced by varies degrees of tilt. Subjects were subjected 0 degrees tilt followed by head down -8 degrees -15 degrees, -30 degrees -15 degrees, -8 degrees, 0 degrees, 15 degrees, 30 degrees , 70 degrees, 30 degrees, 15 degrees and 0 degrees. Each tilt stage was sustained for 15 minutes. Both VP - and haemodynamic changes were continuously recorded 30s before and then for 210 s after the imposition of each tilt step. We used a new computer driven soft and hardware for the analysis of the VP. 3. The VP signal was obtained with a sensor emitting 840 nm (NIR) and 640 nm (RED) light into finger tip with a sample rate of 128 Hz. All data was normalised to the initial mean value obtained at 0 degrees tilt. The signal strength parameters amplitude, and area under the curve and the first derivative of the amplitude (flux) as well as time discrete parameters, time of first maximum (Tmax), dicrote wave (Td), volume pulse decrease (Tdec) and fundamental arterial oscillation Tag = Td - Tmax were measured. 4. HR increased significantly during 30 degrees and 70 degrees tilt, but no change in the other hemodynamic parameters was observed. Amplitude, area under the curve and flux of both the Red and the NIR signal increased following head down tilt. A significant decrease of those parameters was found during foot down tilt. 5. No significant changes were found in the time discrete values, neither within each tilt step nor when compared to the initial mean value at 0 degrees tilt. 6. This study reveals that signal strength related parameters such as area under the curve, amplitude and

  11. 21 Days head-down bed rest induces weakening of cell-mediated immunity - Some spaceflight findings confirmed in a ground-based analog.

    Science.gov (United States)

    Kelsen, Jens; Bartels, Lars Erik; Dige, Anders; Hvas, Christian Lodberg; Frings-Meuthen, Petra; Boehme, Gisela; Thomsen, Marianne Kragh; Fenger-Grøn, Morten; Dahlerup, Jens Frederik

    2012-08-01

    Several studies indicate a weakening of cell-mediated immunity (CMI) and reactivation of latent herpes viruses during spaceflight. We tested the hypothesis that head-down bed rest (HDBR), a ground-based analog of spaceflight, mimics the impact of microgravity on human immunity. Seven healthy young males underwent two periods of 3 weeks HDBR in the test facility of the German Aerospace Center. As a nutritional countermeasure aimed against bone demineralisation, 90 mmol potassium bicarbonate (KHCO(3)) was administered daily in a crossover design. Blood samples were drawn on five occasions. Whole blood was stimulated with antigen i.e. Candida albicans, purified protein derivative (PPD) tuberculin, tetanus toxoid and Cytomegalovirus (CMV) (CMV-QuantiFERON). Flow cytometric analysis included CD4(+)CD25(+)CD127(-)FOXP3(+) regulatory T cells (Tregs), γδ T cells, B cells, NK cells and dendritic cells. In one of the two bed rest periods, we observed a significant decrease in production of interleukin-2 (IL-2), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) following phytohemagglutinin (PHA) stimulation, with a rapid normalization being observed after HDBR. The cytokine levels showed a V-shaped pattern that led to a relativeTh2-shift in cytokine balance. Only three individuals responded to the specific T cell antigens without showing signs of an altered response during HDBR, nor did we observe reactivation of CMV or Epstein-Barr virus (EBV). Of unknown significance, dietary supplementation with KHCO(3) counteracted the decrease in IL-2 levels during HDBR, while there was no impact on other immunological parameters. We conclude that discrete alterations in CMI may be induced by HDBR in selected individuals.

  12. Evaluating Tilt for Wind Plants

    Energy Technology Data Exchange (ETDEWEB)

    Annoni, Jennifer [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Scholbrock, Andrew K. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Churchfield, Matthew J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Fleming, Paul A. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-07-03

    The objective of this work is to demonstrate the feasibility of tilt in a wind plant. Tilt control, much like other wind plant control strategies, has the potential to improve the performance of a wind plant. Tilt control uses the tilt angle of the turbine to direct the wake above or below the downstream turbines. This paper presents a study of tilt in two- and three-turbine arrays. Specifically, the authors show that the power production of a two-turbine array can be increased by tilting turbines in a specific orientation. When adding more turbines, as is shown with the three-turbine array, the overall percentage of power gain increases. This outcome deviates from some of the results seen in typical wind plant control strategies. Finally, we discuss the impact this type of control strategy has on the aerodynamics in a wind plant. This analysis demonstrates that a good understanding of wake characteristics is necessary to improve the plant's performance. A tilt strategy such as the one presented in this paper may have implications for future control/optimization studies including optimization of hub heights in a wind plant and analysis of deep array effects.

  13. REPETITIVE CLUSTER-TILTED ALGEBRAS

    Institute of Scientific and Technical Information of China (English)

    Zhang Shunhua; Zhang Yuehui

    2012-01-01

    Let H be a finite-dimensional hereditary algebra over an algebraically closed field k and CFm be the repetitive cluster category of H with m ≥ 1.We investigate the properties of cluster tilting objects in CFm and the structure of repetitive clustertilted algebras.Moreover,we generalize Theorem 4.2 in [12](Buan A,Marsh R,Reiten I.Cluster-tilted algebra,Trans.Amer.Math.Soc.,359(1)(2007),323-332.) to the situation of CFm,and prove that the tilting graph KCFm of CFm is connected.

  14. Fisica degli atomi e dei nuclei

    CERN Document Server

    Bernardini, Carlo

    1965-01-01

    Evidenza della struttura atomica della materia ; le proprietà degli atomi e la meccanica atomica ; gli atomi e le radiazioni elettromagnetiche ; struttura microscopica dello stato gassoso ; struttura microscopica dello stato liquido ; struttura microscopica della stato solido ; proprietà elettriche e magnetiche delle sostanze ; proprietà dei nuclei degli atomi ; le particelle elementari.

  15. Impaired T-wave amplitude adaptation to heart-rate induced by cardiac deconditioning after 5-days of head-down bed-rest

    Science.gov (United States)

    Caiani, Enrico G.; Pellegrini, Alessandro; Bolea, Juan; Sotaquira, Miguel; Almeida, Rute; Vaïda, Pierre

    2013-10-01

    The study of QT/RR relationship is important for the clinical evaluation of possible risk of acquired or congenital ventricular tachyarrhythmias. In the hypothesis that microgravity exposure could induce changes in the repolarization mechanisms, our aim was to test if a short 5-days strict 6° head-down bed-rest (HDBR) could induce alterations in the QT/RR relationship and spatial repolarization heterogeneity. Twenty-two healthy men (mean age 31±6) were enrolled as part of the European Space Agency HDBR studies. High fidelity (1000 Hz) 24 h Holter ECG (12-leads, Mortara Instrument) was acquired before (PRE), the last day of HDBR (HDT5), and four days after its conclusion (POST). The night period (23:00-06:30) was selected for analysis. X, Y, Z leads were derived and the vectorcardiogram computed. Selective beat averaging was used to obtain averages of P-QRS-T complexes preceded by the same RR (10 ms bin amplitude, in the range 900-1200 ms). For each averaged waveform (i.e., one for each bin), T-wave maximum amplitude (Tmax), T-wave area (Tarea), RTapex, RTend, ventricular gradient (VG) magnitude and spatial QRS-T angle were computed. Non-parametric Friedman test was applied. Compared to PRE, at HDT5 both RTapex and RTend resulted shortened (-4%), with a decrease in T-wave amplitude (-8%) and area (-13%). VG was diminished by 10%, and QRS-T angle increased by 14°. At POST, QT duration and area parameters, as well as QRS-T angle were restored while Tmax resulted larger than PRE (+5%) and VG was still decreased by 3%. Also, a marked loss in strength of the linear regression with RR was found at HDT5 in Tmax and Tarea, that could represent a new dynamic marker of increased risk for life-threatening arrhythmias. Despite the short-term HDBR, ventricular repolarization during the night period was affected. This should be taken into account in astronauts for risk assessment during space flight.

  16. Plasma volume and water/sodium balance differences due to sex and menstrual phase after 4 hours of head-down bed rest (HDBR).

    Science.gov (United States)

    Edgell, Heather; Grinberg, Anna; Beavers, Keith; Gagne, Nathalie; Totosy de Zepetnek, Julia; Greaves, Danielle; Hughson, Richard L.

    In both sexes, orthostatic responses are impaired by spaceflight or head-down bed-rest (HDBR), with a greater impact in women. Decreased plasma volume (PV) could contribute to reductions in cardiac output and blood pressure upon an orthostatic challenge. We hypothesized that a greater decrease in PV in women might lead to poorer orthostatic responses. We further hypothesized that the responses in women would differ throughout the menstrual cycle. We studied the responses of men (n=6) and women (n= 6) to 4-hr HDBR and 4-hr seated control (SEAT). Furthermore, we studied women in both the follicular (Day 8-11) and luteal (Day 18-24) phases of menstruation in a repeated measures design. After 4-hr HDBR, PV decreased in men (-175.1 ± 56.8 mL; vs. SEAT: P=0.076) and in the follicular phase, but did not change in the luteal phase (Luteal: -55.0 ± 54.6 mL; Follicular: -226.4 ± 88.2 mL (Interaction effect: P=0.01)). After 4-hr HDBR, only men appear to exhibit increased urine volume (Men, difference from SEAT: +298.3 ± 105.5 mL; Luteal, difference from SEAT: +59.4 ± 34.3 mL; Follicular, difference from SEAT: +43.7 ± 190.0 mL; P=0.16). No changes in urinary sodium after 4-hr HDBR were observed in any group (Men, difference from SEAT: -16.5 ± 13.5 µmol; Luteal, difference from SEAT: -8.0 ± 8.8 µmol; Follicular, difference from SEAT: +28.2 ± 29.5 µmol; P=0.264). No changes in urinary osmolarity were observed after 4-hr HDBR in any group (Men, difference from SEAT: -38.8 ± 126.2 mmol/kg; Luteal, difference from SEAT: -85.1 ± 66.9 mmol/kg; Follicular, difference from SEAT: -99.1 ± 98.5 mmol/kg; P=0.906). The changes in plasma volume do not appear to be a result of urinary water and sodium loss. Perhaps actions of atrial natriuretic peptide, urodilatin, the RAAS pathway, and/or capillary filtration are involved. From these observed changes in plasma volume, we surmise that women in the follicular phase of the menstrual cycle may exhibit lower cardiac output and thus

  17. Tibiotalar tilt - a new slant

    Energy Technology Data Exchange (ETDEWEB)

    Griffiths, H.; Wandtke, J.

    1981-05-01

    Classically tibiotalar tilt (TTT) is associated with four conditions: Fairbanks disease, hemophilia, sickle-cell anemia and juvenile rheumatoid arthritis. We have found it to be present in at least 20 other conditions including other dysplasias, developmental conditions such as fibrous dysplasia and a variety of other acquired disorders including various metabolic diseases and following previous trauma. The pathogenesis is controversial, but the most probable cause is related to stress and the blood supply of the distal tibial epiphysis. The differentiation of TTT from pseudotibiotalar tilt is also discussed.

  18. Height and Tilt Geometric Texture

    DEFF Research Database (Denmark)

    Andersen, Vedrana; Desbrun, Mathieu; Bærentzen, Jakob Andreas

    2009-01-01

    We propose a new intrinsic representation of geometric texture over triangle meshes. Our approach extends the conventional height field texture representation by incorporating displacements in the tangential plane in the form of a normal tilt. This texture representation offers a good practical...... compromise between functionality and simplicity: it can efficiently handle and process geometric texture too complex to be represented as a height field, without having recourse to full blown mesh editing algorithms. The height-and-tilt representation proposed here is fully intrinsic to the mesh, making...

  19. 15d-6°头低位卧床对女性立位耐力的影响%Effects of 15 d - 6 ° Head-down Bed Rest on Female Orthostatic Tolerance.

    Institute of Scientific and Technical Information of China (English)

    谈诚; 杨鸿慧; 王林杰; 李莹辉; 白延强; 曹毅; 张丽芬; 袁敏; 王惠娟; 牛东滨; 赵琦; 李志利; 陈文娟

    2011-01-01

    Objective To explore the effects of 15 d -6° head-down bed rest(HDBR) on female orthostatic tolerance for future countermeasure in outer space.Methods Fifteen female volunteers experienced the 15 d HDBR.They underwent 70° tilting test(TT) on the day before and after HDBR respectively.The blood samples before and after each Tr were analyzed for detecting the changes of plasma rennin activity (PRA) , angiotensin Ⅱ (ATⅡ) and noradrenalin(NE) concentration.Results After 15 d HDBR, 8/15(53.3% ) subjects showed orthostatic intolerance.Among them, 6/15 (40.0%) experienced cessation of pre-syncope syndrome,2/15 (13.3%) experienced cessation of postural tachycardia syndrome (POTS).The diastolic blood pressure,heart rate(HR) and total peripheral resistance(TPR) increased significantly under TT( P < 0.05 ), whereas the stroke volume(SⅤ) and cardiac output(CO) decreased( P < 0.05 ).The diastolic pressure(DIA) and HR in post-HDBR were higher than those in pre-HDBR, but the TPR and CO were not affected (P > 0.05).The main difference between normal group(Normal) and orthostatic intolerance group (Oler) lied in that the HR increment under TT in Oler group was significantly greater than those in normal group.Biochemical blood tests showed that there was significant difference between the two groups in NE basehne level at rest (supine) posture, but no difference in the variation scope of NE level under TT( P > 0.05 ).Plasmic AT Ⅱ level increased significantly after TT.The PRA was reduced significantly after 15 d HDBR(P <0.01 ).Conclusion The incidence of OI after HDBR is quite high in female, which is showed in manifestation of diversity.%目的 研究15 d-6°头低位卧床(HDBR)对女性立位耐力的影响.方法 15名女性青年志愿者经历15 d-6°HDBR,于卧床前1天及卧床后第l天分别接受70°被动立位测试,记录测试全程的心血管血液动力学指标,同时观察血浆肾素活性(PRA)、血管紧张素Ⅱ(ATⅡ)和去甲肾

  20. Effects of Frequency and Motion Paradigm on Perception of Tilt and Translation During Periodic Linear Acceleration

    Science.gov (United States)

    Beaton, K. H.; Holly, J. E.; Clement, G. R.; Wood, Scott J.

    2009-01-01

    Previous studies have demonstrated an effect of frequency on the gain of tilt and translation perception. Results from different motion paradigms are often combined to extend the stimulus frequency range. For example, Off-Vertical Axis Rotation (OVAR) and Variable Radius Centrifugation (VRC) are useful to test low frequencies of linear acceleration at amplitudes that would require impractical sled lengths. The purpose of this study was to compare roll-tilt and lateral translation motion perception in 12 healthy subjects across four paradigms: OVAR, VRC, sled translation and rotation about an earth-horizontal axis. Subjects were oscillated in darkness at six frequencies from 0.01875 to 0.6 Hz (peak acceleration equivalent to 10 deg, less for sled motion below 0.15 Hz). Subjects verbally described the amplitude of perceived tilt and translation, and used a joystick to indicate the direction of motion. Consistent with previous reports, tilt perception gain decreased as a function of stimulus frequency in the motion paradigms without concordant canal tilt cues (OVAR, VRC and Sled). Translation perception gain was negligible at low stimulus frequencies and increased at higher frequencies. There were no significant differences between the phase of tilt and translation, nor did the phase significantly vary across stimulus frequency. There were differences in perception gain across the different paradigms. Paradigms that included actual tilt stimuli had the larger tilt gains, and paradigms that included actual translation stimuli had larger translation gains. In addition, the frequency at which there was a crossover of tilt and translation gains appeared to vary across motion paradigm between 0.15 and 0.3 Hz. Since the linear acceleration in the head lateral plane was equivalent across paradigms, differences in gain may be attributable to the presence of linear accelerations in orthogonal directions and/or cognitive aspects based on the expected motion paths.

  1. Resolution enhancement in tilted coordinates

    Science.gov (United States)

    Hariri Naghadeh, Diako; Keith Morley, Christopher

    2016-11-01

    Deconvolution is applied to remove source wavelet effects from seismograms. The results are resolution enhancement that enables detection of thin layers. Following enhancement of resolution, low frequency and high angle reflectors, particularly at great depth, appear as low amplitude and semi-invisible reflectors that are difficult to track and pick. A new approach to enhance resolution is introduced that estimates a derivative using continuous wavelet transform in tilted coordinates. The results are compared with sparse spike deconvolution, curvelet deconvolution and inverse quality filtering in wavelet domain. The positive consequence of the new method is to increase sampling of high dip features by changing the coordinate system from Cartesian to tilted. To compare those methods a complex data set was chosen that includes high angle faults and chaotic mass transport complex. Image enhancement using curvelet deconvolution shows a chaotic system as a non-chaotic one. The results show that sparse spike deconvolution and inverse quality filtering in wavelet domain are able to enhance resolution more than curvelet deconvolution especially at great depth but it is impossible to follow steep dip reflectors after resolution enhancement using these methods, especially when their apparent dips are more than 45°. By estimating derivatives in a continuous wavelet transform from tilted data sets similar resolution enhancement as the other deconvolution methods is achieved but additionally steep dipping reflectors are imaged much better than others. Subtracted results of the enhanced resolution data set using new method and the other introduced methods show that steeply dipping reflectors are highlighted as a particular ability of the new method. The results show that high frequency recovery in Cartesian co-ordinate is accompanied by inability to image steeply dipping reflectors especially at great depths. Conversely recovery of high frequency data and imaging of the data

  2. Compensated-power differential calorimeter -196 deg. C/400 deg. C; Calorimetre differentiel a puissance compensee -196 deg. C/400 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Bonjour, E.; Pierre, J.; Agagliate, S.; Bertrand, P.; Faivre, J.; Lagnier, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires, Section physico-chimie et basses temperatures

    1967-06-01

    A differential calorimetric device of original design is described. Its allows direct measurements of thermal effects (adsorption or release) during a linear rise of temperature. The self compensated power method which is applied by means of a very sensitive control system, gives a direct value of the different heat capacity between the sample and a dummy of it. The detection threshold is about {+-} 100 micro-watts to {+-} 250 micro-watts. Applications: - Generally measurements of enthalpy changes of massive or powdered samples. - Measurement of Wigner energy after low temperature irradiation (77 deg. K). - Measurements of energy release in low temperature (77 deg. K) cold worked metals. (authors) [French] On decrit un dispositif de calorimetrie differentielle, de conception originale, qui permet de mesurer directement des effets thermiques en absorption ou en degagement de chaleur, au cours d'une montee en temperature lineaire. La methode de compensation automatique de puissance qui est mise en oeuvre au moyen de cha es d'asservissement tres sensibles, conduit a une determination directe de la capacite calorifique differencielle entre l'echantillon et sa reference. Le seuil de detection est de l'ordre de {+-} 100 a {+-} 250 microwatts. Applications: - D'une facon generale, mesure des variations enthalpiques, sur echantillons massifs ou en poudre. - Mesure de l'energie Wigner apres irradiation a basse temperature (77 deg. K). - Mesure de l'energie restauree apres deformation des metaux a basse temperature (77 deg. K). (auteurs)

  3. Testimonianze di vittime degli anni di piombo

    DEFF Research Database (Denmark)

    Cecchini, Leonardo

    Testimonianze di vittime degli anni di piombo In un articolo pubblicato nel 2008 sulla webzine Nazione indiana Christian Raimo criticava quello che poi Giovanni De Luna qualche anno dopo nel suo libro La Repubblica del dolore (2011) ha chiamato “paradigma vittimario”; cioè la presenza predominante...

  4. Comparison of PCBBs and CTs irradiated at 250 deg. C, 300 deg. C, and 350 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Rensman, J.; Nolles, H.N. [ECN-Energy Research Foundation, Research Unit NRG, Westerduinweg, Petten (Netherlands); Lucon, E. [SCK-CEN, Institute of Nuclear Material Science, Boeretang, Mol (Belgium); Spatig, P. [EPFL-CRDP, Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, CH Villigen PSI (Switzerland)

    2007-07-01

    Full text of publication follows: The fracture toughness of irradiated Eurofer steel is difficult to characterise. Several limitations are identified in this paper with respect to the conventional treatment of fracture data of BCC steels in the transition region. It is uncertain that the RPV Master Curve is applicable to unirradiated Eurofer, and low temperature irradiation adds more to this uncertainty. The lack of strain hardening and the dose variation within each batch are two complicating factors. An irradiation has been carried out in the BFR up to a nominal dose of 2.5 dpa at 250 deg. C, 300 deg. C, and 350 deg. C in sodium. Twelve small size pre-cracked bend specimens and eight mini-CT specimens have been irradiated in each temperature section. We analyse the effect of constraint and censoring limit, and the specimen geometry and loading configuration. The fracture data are treated in several ways that are proposed in open literature to investigate the effect of irradiation on a reference temperature like the ASTM E1921 T0. In addition, the relation between the tensile hardening, which is presented in a companion paper, and the shift calculated with the various methods is studied. (authors)

  5. Bacillus subtilis Two-Component System Sensory Kinase DegS Is Regulated by Serine Phosphorylation in Its Input Domain

    Science.gov (United States)

    Jers, Carsten; Kobir, Ahasanul; Søndergaard, Elsebeth Oline; Jensen, Peter Ruhdal; Mijakovic, Ivan

    2011-01-01

    Bacillus subtilis two-component system DegS/U is well known for the complexity of its regulation. The cytosolic sensory kinase DegS does not receive a single predominant input signal like most two-component kinases, instead it integrates a wide array of metabolic inputs that modulate its activity. The phosphorylation state of the response regulator DegU also does not confer a straightforward “on/off” response; it is fine-tuned and at different levels triggers different sub-regulons. Here we describe serine phosphorylation of the DegS sensing domain, which stimulates its kinase activity. We demonstrate that DegS phosphorylation can be carried out by at least two B. subtilis Hanks-type kinases in vitro, and this stimulates the phosphate transfer towards DegU. The consequences of this process were studied in vivo, using phosphomimetic (Ser76Asp) and non-phosphorylatable (Ser76Ala) mutants of DegS. In a number of physiological assays focused on different processes regulated by DegU, DegS S76D phosphomimetic mutant behaved like a strain with intermediate levels of DegU phosphorylation, whereas DegS S76A behaved like a strain with lower levels of DegU phophorylation. These findings suggest a link between DegS phosphorylation at serine 76 and the level of DegU phosphorylation, establishing this post-translational modification as an additional trigger for this two-component system. PMID:21304896

  6. Bacillus subtilis two-component system sensory kinase DegS is regulated by serine phosphorylation in its input domain.

    Directory of Open Access Journals (Sweden)

    Carsten Jers

    Full Text Available Bacillus subtilis two-component system DegS/U is well known for the complexity of its regulation. The cytosolic sensory kinase DegS does not receive a single predominant input signal like most two-component kinases, instead it integrates a wide array of metabolic inputs that modulate its activity. The phosphorylation state of the response regulator DegU also does not confer a straightforward "on/off" response; it is fine-tuned and at different levels triggers different sub-regulons. Here we describe serine phosphorylation of the DegS sensing domain, which stimulates its kinase activity. We demonstrate that DegS phosphorylation can be carried out by at least two B. subtilis Hanks-type kinases in vitro, and this stimulates the phosphate transfer towards DegU. The consequences of this process were studied in vivo, using phosphomimetic (Ser76Asp and non-phosphorylatable (Ser76Ala mutants of DegS. In a number of physiological assays focused on different processes regulated by DegU, DegS S76D phosphomimetic mutant behaved like a strain with intermediate levels of DegU phosphorylation, whereas DegS S76A behaved like a strain with lower levels of DegU phophorylation. These findings suggest a link between DegS phosphorylation at serine 76 and the level of DegU phosphorylation, establishing this post-translational modification as an additional trigger for this two-component system.

  7. InAs 2DEGs:What's the g-factor?

    Science.gov (United States)

    McCombe, B. D.; Pakmehr, Mehdi; Khaetskii, A.; Chiatti, Olivio; Fischer, S. F.; Buchholz, S.; Heyn, C.; Hansen, W.; Cahay, M.; Newrock, R. S.; Bandari, Nikhil

    2014-03-01

    Interest in spin-orbit effects in semiconductors has led us to study the electron g-factor in quasi-2DEG InAs samples. We have made magneto-transport and -photoresponse (PR) measurements on InAs QW structures in magnetic fields up to 10 T. THz cyclotron resonance (CR) is manifested in PR as a resonant envelope of the amplitude of quantum oscillations, which show clear spin-splitting (for lower mobility samples) down 4T, while direct R_xx measurements show no spin-splitting up to 9T. R_xx oscillations in a higher mobility sample show well-resolved spin-splittings over a range of fields as does the PR. We have simulated the data with a theoretical expression for 2DEG SdH oscillations (coupled with CR resonant carrier heating for the PR) and extracted g-factors from fits. We also used a different (commonly used) method, SdH oscillations vs. tilt angle of the field to extract g-factors from the angle at which the SdH frequency doubles. We find very large g-factors from fits to R_xx and PR (14 - 20), but g-factors 2-3 times smaller for these same samples from tilted field experiments (close to estimated band g-factors). These results are discussed in terms of exchange effects. Support: NSF DMR 1008138 (Buffalo); NSF ECCE 1028483(Cincinnati); DFG Fi932/4-1(Berlin).

  8. 30d头低位卧床对人脑灰质密度的影响%Effects of 30 d Head-down Bed Rest on Density of Human Brain Grey Matter

    Institute of Scientific and Technical Information of China (English)

    顾正章; 金真; 曾亚伟; 朱磊; 李科; 张磊; 范勇

    2012-01-01

    Objective To investigate the effect of head-down bed rest( HDBR) on density of human brain grey matter . Methods Fourteen healthy male volunteers underwent - 6° 30 d HDBR simulated microgravity. High-resolution brain anatomical imaging data were collected with a 3.0 T superconducting MR imaging system before and after HDBR. With voxel-based morphometry (VBM) module of analysis software package SPM8, the pre- and post-HDBR image data of density of whole brain grey matter were calculated and compared. Results After HDBR, the density of grey matter was decreased significantly in the bilateral thalamus, bilateral occipital lobe and right inferior parietal lobule ( P < 0. 005 ). Conclusion HDBR simulated microgravity may cause density changes in brain grey matter of normal adults.%目的 探讨头低位卧床(head-down bed rest,HDBR)对人脑灰质密度的影响.方法 14名男性健康志愿者,进行为期30 d的-6°头低位模拟微重力卧床实验.使用3.0T超导MR成像系统采集卧床前后的高分辨率全脑解剖成像数据,用SPM8软件进行基于体素的形态学分析(VBM),比较志愿者卧床前后的脑灰质密度变化.结果 卧床后志愿者双侧丘脑、双侧枕叶、右侧顶下小叶的灰质密度减少(P<0.005).结论 模拟微重力环境可致正常成年人脑灰质密度发生改变.

  9. Dark tip-tilt sensing

    CERN Document Server

    Arcidiacono, Carmelo; Viotto, Valentina; Bergomi, Maria; Farinato, Jacopo; Magrin, Demetrio; Dima, Marco; Gullieuszik, Marco; Marafatto, Luca

    2016-01-01

    Dark wavefront sensing in its simplest and more crude form is a quad-cell with a round spot of dark ink acting as occulting disk at the center. This sensor exhibits fainter limiting magnitude than a conventional quad-cell, providing that the size of the occulting disk is slightly smaller than the size of the spot and smaller than the residual jitter movement in closed loop. We present simulations focusing a generic Adaptive Optics system using Natural Guide Stars to provide the tip-tilt signal. We consider a jitter spectrum of the residual correction including amplitudes exceeding the dark disk size.

  10. Molecular tilt on monolayer-protected nanoparticles

    KAUST Repository

    Giomi, L.

    2012-02-01

    The structure of the tilted phase of monolayer-protected nanoparticles is investigated by means of a simple Ginzburg-Landau model. The theory contains two dimensionless parameters representing the preferential tilt angle and the ratio ε between the energy cost due to spatial variations in the tilt of the coating molecules and that of the van der Waals interactions which favors the preferential tilt. We analyze the model for both spherical and octahedral particles. On spherical particles, we find a transition from a tilted phase, at small ε, to a phase where the molecules spontaneously align along the surface normal and tilt disappears. Octahedral particles have an additional phase at small ε characterized by the presence of six topological defects. These defective configurations provide preferred sites for the chemical functionalization of monolayer-protected nanoparticles via place-exchange reactions and their consequent linking to form molecules and bulk materials. Copyright © EPLA, 2012.

  11. Human muscle sympathetic neural and haemodynamic responses to tilt following spaceflight

    Science.gov (United States)

    Levine, Benjamin D.; Pawelczyk, James A.; Ertl, Andrew C.; Cox, James F.; Zuckerman, Julie H.; Diedrich, Andre; Biaggioni, Italo; Ray, Chester A.; Smith, Michael L.; Iwase, Satoshi; Saito, Mitsuru; Sugiyama, Yoshiki; Mano, Tadaaki; Zhang, Rong; Iwasaki, Kenichi; Lane, Lynda D.; Buckey, Jay C Jr; Cooke, William H.; Baisch, Friedhelm J.; Eckberg, Dwain L.; Blomqvist, C. Gunnar

    2002-01-01

    Orthostatic intolerance is common when astronauts return to Earth: after brief spaceflight, up to two-thirds are unable to remain standing for 10 min. Previous research suggests that susceptible individuals are unable to increase their systemic vascular resistance and plasma noradrenaline concentrations above pre-flight upright levels. In this study, we tested the hypothesis that adaptation to the microgravity of space impairs sympathetic neural responses to upright posture on Earth. We studied six astronauts approximately 72 and 23 days before and on landing day after the 16 day Neurolab space shuttle mission. We measured heart rate, arterial pressure and cardiac output, and calculated stroke volume and total peripheral resistance, during supine rest and 10 min of 60 deg upright tilt. Muscle sympathetic nerve activity was recorded in five subjects, as a direct measure of sympathetic nervous system responses. As in previous studies, mean (+/- S.E.M.) stroke volume was lower (46 +/- 5 vs. 76 +/- 3 ml, P = 0.017) and heart rate was higher (93 +/- 1 vs. 74 +/- 4 beats min(-1), P = 0.002) during tilt after spaceflight than before spaceflight. Total peripheral resistance during tilt post flight was higher in some, but not all astronauts (1674 +/- 256 vs. 1372 +/- 62 dynes s cm(-5), P = 0.32). No crew member exhibited orthostatic hypotension or presyncopal symptoms during the 10 min of postflight tilting. Muscle sympathetic nerve activity was higher post flight in all subjects, in supine (27 +/- 4 vs. 17 +/- 2 bursts min(-1), P = 0.04) and tilted (46 +/- 4 vs. 38 +/- 3 bursts min(-1), P = 0.01) positions. A strong (r(2) = 0.91-1.00) linear correlation between left ventricular stroke volume and muscle sympathetic nerve activity suggested that sympathetic responses were appropriate for the haemodynamic challenge of upright tilt and were unaffected by spaceflight. We conclude that after 16 days of spaceflight, muscle sympathetic nerve responses to upright tilt are normal.

  12. Tilting Uranus without a Collision

    Science.gov (United States)

    Rogoszinski, Zeeve; Hamilton, Douglas P.

    2016-10-01

    The most accepted hypothesis for the origin of Uranus' 98° obliquity is a giant collision during the late stages of planetary accretion. This model requires a single Earth mass object striking Uranus at high latitudes; such events occur with a probability of about 10%. Alternatively, Uranus' obliquity may have arisen from a sequence of smaller impactors which lead to a uniform distribution of obliquities. Here we explore a third model for tilting Uranus using secular spin-orbit resonance theory. We investigate early Solar System configurations in which a secular resonance between Uranus' axial precession frequency and another planet's orbital node precession frequency might occur.Thommes et al. (1999) hypothesized that Uranus and Neptune initially formed between Jupiter and Saturn, and were then kicked outward. In our scenario, Neptune leaves first while Uranus remains behind. As an exterior Neptune slowly migrates outward, it picks up both Uranus and Saturn in spin-orbit resonances (Ward and Hamilton 2004; Hamilton and Ward 2004). Only a distant Neptune has a nodal frequency slow enough to resonate with Uranus' axial precession.This scenario, with diverging orbits, results in resonance capture. As Neptune migrates outward its nodal precession slows. While in resonance, Uranus and Saturn each tilt a bit further, slowing their axial precession rates to continually match Neptune's nodal precession rate. Tilting Uranus to high obliquities takes a few 100 Myrs. This timescale may be too long to hold Uranus captive between Jupiter and Saturn, and we are investigating how to reduce it. We also find that resonance capture is rare if Uranus' initial obliquity is greater than about 10°, as the probability of capture decreases as the planet's initial obliquity increases. We will refine this estimate by quantifying capture statistics, and running accretion simulations to test the likelihood of a low early obliquity. Our preliminary findings show that most assumptions about

  13. Global map of lithosphere thermal thickness on a 1 deg x 1 deg grid - digitally available

    DEFF Research Database (Denmark)

    Artemieva, Irina

    2014-01-01

    than 250 km) lithosphere is restrictedsolely to young Archean terranes (3.0–2.6 Ga), while in old Archean cratons (3.6–3.0 Ga) lithospheric roots donot extend deeper than 200–220 km.The TC1 model is presented by a set of maps, which show significant thermal heterogeneity within continentalupper mantle......This presentation reports a 1 deg 1 deg global thermal model for the continental lithosphere (TC1). The modelis digitally available from the author’s web-site: www.lithosphere.info.Geotherms for continental terranes of different ages (early Archean to present) are constrained by reliabledata...

  14. Large optics inspection, tilting, and washing stand

    Science.gov (United States)

    Ayers, Marion Jay; Ayers, Shannon Lee

    2010-08-24

    A large optics stand provides a risk free means of safely tilting large optics with ease and a method of safely tilting large optics with ease. The optics are supported in the horizontal position by pads. In the vertical plane the optics are supported by saddles that evenly distribute the optics weight over a large area.

  15. Investigation of fiber tilt in paperboard

    Science.gov (United States)

    John M. Considine; David W. Vahey

    2008-01-01

    The introduction of short, tilted rods to reinforce polymer composite laminates has resulted in near doubling the strength of lap shear specimens. Paperboard is predominantly a multi-layered structure, similar to composite laminates in many ways. Improved bonding between layers should have a positive influence on mechanical performance. Tilted fibers, or z-direction...

  16. Bacillus subtilis Two-Component System Sensory Kinase DegS Is Regulated by Serine Phosphorylation in Its Input Domain

    DEFF Research Database (Denmark)

    Jers, Carsten; Kobir, Ahasanul; Søndergaard, Elsebeth Oline;

    2011-01-01

    Bacillus subtilis two-component system DegS/U is well known for the complexity of its regulation. The cytosolic sensory kinase DegS does not receive a single predominant input signal like most two-component kinases, instead it integrates a wide array of metabolic inputs that modulate its activity...

  17. Angiopatia diabetica e amputazione degli arti inferiori: valutazioni preliminari degli episodi di ricovero ripetuti

    Directory of Open Access Journals (Sweden)

    P. Trerotoli

    2003-05-01

    Full Text Available

    Obiettivi: l’obiettivo principale dello studio è stata la valutazione dei ricoveri ripetuti nei soggetti con vasculopatia diabetica, rispetto ai soggetti con vasculopatia non diabetica.

    Materiali e Metodi: sono state selezionate le SDO del triennio 1998-2000 contenenti, in uno dei campi di diagnosi, i codici di diabete mellito, con e senza complicanze (codici ICD9 ed ICD9CM, 250.—, vasculopatia periferica (440.2 e 440.8, ulcera periferica (707.1, 707.8, 707.9, gangrena (785.4. Le SDO con diagnosi di vasculopatia diabetica sono state considerate come angiopatie diabetiche (AD; le altre sono state attribuite agli angiopatici non diabetici (AND. Le SDO con diabete non complicato e arteriopatia periferica sono state eliminate. L’intervento di amputazione è stato individuato dalla presenza del codice ICD9CM di procedura 84.—. La ripetitività degli episodi è stata valutata usando il codice fiscale come identificativo del paziente. Risultati: sono state rilevate 5814 dimissioni di AD e 9010 di AND. Le amputazioni sono state 285 (4,90% negli AD e 485 (5,38% negli AND. I ricoveri ripetuti sono stati 13 negli AD e 12 negli AND. Le amputazioni sono state osservate verso il 4°-5° episodio di ricovero negli AD, mentre già dal 2° episodio negli AND. Le ulcere erano presenti nel 36,05% (il 36,5% nel primo episodio di ricovero, che resta costante negli episodi successivi degli AND e nel 10,97% degli AD (9,84% nel primo episodio, con un incremento fino al 20% del 5° episodio. Un episodio in day-hospital (DH si osserva nel 12,32% degli AD, contro il 4,20% degli AND.

    Conclusioni: l’accesso degli AD all’assistenza intraospedaliera avviene più frequentemente in DH, i passi successivi sono caratterizzati dalla comparsa dell’ulcera o gangrena e infine dall’amputazione. Nel gruppo degli AD è stato osservato un eccesso di ospedalizzazione, probabilmente per ripetitività del

  18. Study of mine stability using records of ground tilting

    CSIR Research Space (South Africa)

    Spottiswoode, SM

    2006-06-01

    Full Text Available to estimate tilting from mining, assuming elastic rock mass behaviour. Some suggestions for further work are made. These include studying changes in a seismic tilting following tilt events associated with shrinking pillars. This might provide more direct...

  19. Evaluating Tilt for Wind Farms: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Annoni, Jennifer; Scholbrock, Andrew; Churchfield, Matthew; Fleming, Paul

    2017-06-29

    The objective of this work is to demonstrate the feasibility of tilt in a wind plant. Tilt control, much like other wind plant control strategies, has the potential to improve the performance of a wind plant. Tilt control uses the tilt angle of the turbine to direct the wake above or below the downstream turbines. This paper presents a study of tilt in two- and threeturbine arrays. Specifically, the authors show that the power production of a two-turbine array can be increased by tilting turbines in a specific orientation. When adding more turbines, as is shown with the three-turbine array, the overall percentage of power gain increases. This outcome deviates from some of the results seen in typical wind plant control strategies. Finally, we discuss the impact this type of control strategy has on the aerodynamics in a wind plant. This analysis demonstrates that a good understanding of wake characteristics is necessary to improve the plant's performance. A tilt strategy such as the one presented in this paper may have implications for future control/optimization studies including optimization of hub heights in a wind plant and analysis of deep array effects.

  20. Global map of lithosphere thermal thickness on a 1 deg x 1 deg grid - digitally available

    Science.gov (United States)

    Artemieva, Irina

    2014-05-01

    This presentation reports a 1 deg ×1 deg global thermal model for the continental lithosphere (TC1). The model is digitally available from the author's web-site: www.lithosphere.info. Geotherms for continental terranes of different ages (early Archean to present) are constrained by reliable data on borehole heat flow measurements (Artemieva and Mooney, 2001), checked with the original publications for data quality, and corrected for paleo-temperature effects where needed. These data are supplemented by cratonic geotherms based on xenolith data. Since heat flow measurements cover not more than half of the continents, the remaining areas (ca. 60% of the continents) are filled by the statistical numbers derived from the thermal model constrained by borehole data. Continental geotherms are statistically analyzed as a function of age and are used to estimate lithospheric temperatures in continental regions with no or low quality heat flow data. This analysis requires knowledge of lithosphere age globally. A compilation of tectono-thermal ages of lithospheric terranes on a 1 deg × 1 deg grid forms the basis for the statistical analysis. It shows that, statistically, lithospheric thermal thickness z (in km) depends on tectono-thermal age t (in Ma) as: z=0.04t+93.6. This relationship formed the basis for a global thermal model of the continental lithosphere (TC1). Statistical analysis of continental geotherms also reveals that this relationship holds for the Archean cratons in general, but not in detail. Particularly, thick (more than 250 km) lithosphere is restricted solely to young Archean terranes (3.0-2.6 Ga), while in old Archean cratons (3.6-3.0 Ga) lithospheric roots do not extend deeper than 200-220 km. The TC1 model is presented by a set of maps, which show significant thermal heterogeneity within continental upper mantle. The strongest lateral temperature variations (as large as 800 deg C) are typical of the shallow mantle (depth less than 100 km). A map of the

  1. Global map of lithosphere thermal thickness on a 1 deg x 1 deg grid - digitally available

    DEFF Research Database (Denmark)

    Artemieva, Irina

    2014-01-01

    than 250 km) lithosphere is restrictedsolely to young Archean terranes (3.0–2.6 Ga), while in old Archean cratons (3.6–3.0 Ga) lithospheric roots donot extend deeper than 200–220 km.The TC1 model is presented by a set of maps, which show significant thermal heterogeneity within continentalupper mantle......This presentation reports a 1 deg 1 deg global thermal model for the continental lithosphere (TC1). The modelis digitally available from the author’s web-site: www.lithosphere.info.Geotherms for continental terranes of different ages (early Archean to present) are constrained by reliabledata...... of the continents, the remaining areas (ca. 60% ofthe continents) are filled by the statistical numbers derived from the thermal model constrained by boreholedata. Continental geotherms are statistically analyzed as a function of age and are used to estimate lithospherictemperatures in continental regions...

  2. Tilting mutation of Brauer tree algebras

    CERN Document Server

    Aihara, T

    2010-01-01

    We define tilting mutations of symmetric algebras as the endomorphism algebras of Okuyama-Rickard complexes. For Brauer tree algebras, we give an explicit description of the change of Brauer trees under mutation.

  3. Aurelia aurita bio-inspired tilt sensor

    Science.gov (United States)

    Smith, Colin; Villanueva, Alex; Priya, Shashank

    2012-10-01

    The quickly expanding field of mobile robots, unmanned underwater vehicles, and micro-air vehicles urgently needs a cheap and effective means for measuring vehicle inclination. Commonly, tilt or inclination has been mathematically derived from accelerometers; however, there is inherent error in any indirect measurement. This paper reports a bio-inspired tilt sensor that mimics the natural balance organ of jellyfish, called the ‘statocyst’. Biological statocysts from the species Aurelia aurita were characterized by scanning electron microscopy to investigate the morphology and size of the natural sensor. An artificial tilt sensor was then developed by using printed electronics that incorporates a novel voltage divider concept in conjunction with small surface mount devices. This sensor was found to have minimum sensitivity of 4.21° with a standard deviation of 1.77°. These results open the possibility of developing elegant tilt sensor architecture for both air and water based platforms.

  4. Effects of Long Duration Spaceflight on Venous and Arterial Compliance: Bed Rest

    Science.gov (United States)

    Ribeiro, L. Christine; Platts, Steven H.; Laurie, Steven S.; Lee, Stuart M. C.; Martin, David S.; Ploutz-Snyder, Robert J.; Stenger, Michael B.

    2017-01-01

    The primary objective was to determine whether a high sodium diet during bed rest induced alterations in vascular compliance and was related to the incidence of VIIP. Ocular structural and functional measures and vascular ultrasound of the head and neck were acquired in bed rest subjects completing 10-14 days in 6deg head-down tilt.

  5. NCLB Heads Down Alice's Rabbit Hole

    Science.gov (United States)

    Starnes, Bobby Ann

    2005-01-01

    This article describes one unconventional elementary school teacher's frustrations with colleagues doubting her competence, intelligence, and sense of purpose as a teacher. In her classroom, she never used textbooks or had a teacher's desk. There were no contests, gold stars, or redbird reading groups. There were no school-supply decorations,…

  6. Tilting Shear Layers in Coastal Flows

    Science.gov (United States)

    2015-09-30

    2181 email: khelfrich@whoi.edu Brian L. White Department of Marine Sciences University of North Carolina at Chapel Hill 3117c Venable Hall ...and rotation. Figure 1. a) Sketch of tilting, horizontal shear layer near Stuart Island from Farmer et al (2002). b) Photograph of the...surface expression of intense vortices near Stuart Island (from Farmer et al, 2002). c) Infra-red image of a tilting shear layer in the Snohomish River

  7. OMP Peptides Activate the DegS Stress-Sensor Protease by a Relief of Inhibition Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Jungsan; Grant, Robert A.; Sauer, Robert T.; MIT

    2010-03-19

    In the E. coli periplasm, C-terminal peptides of misfolded outer-membrane porins (OMPs) bind to the PDZ domains of the trimeric DegS protease, triggering cleavage of a transmembrane regulator and transcriptional activation of stress genes. We show that an active-site DegS mutation partially bypasses the requirement for peptide activation and acts synergistically with mutations that disrupt contacts between the protease and PDZ domains. Biochemical results support an allosteric model, in which these mutations, active-site modification, and peptide/substrate binding act in concert to stabilize proteolytically active DegS. Cocrystal structures of DegS in complex with different OMP peptides reveal activation of the protease domain with varied conformations of the PDZ domain and without specific contacts from the bound OMP peptide. Taken together, these results indicate that the binding of OMP peptides activates proteolysis principally by relieving inhibitory contacts between the PDZ domain and the protease domain of DegS.

  8. La poesia sabiana degli Anni Venti

    Directory of Open Access Journals (Sweden)

    Atilij Rakar

    1975-11-01

    Full Text Available Muovendo da un confronto fra il Saba del primo Canzoniere e le Figure e canti coi quali l'opera del poeta triestino continua negli anni venti, l'autore cerca di individuare i caratteri che meglio definiscono la poesia sabiana di questo secondo periodo. Messi in evidenza alcuni temi su cui verte il discorso sabiano fin delle Poesie dell'adolescenza e giovanili, le opere degli anni venti si rivelano come esiti di un poliforme compendio in cui il poeta vuol chiarire il senso del cammino percorso e comp:tendere quelle che sono le ragioni prime del suo poetare. Si manifestano qui, anche in maniera esplicita, alcuni motivi fondamentali del Canzionere: basti pensare, ad esempio, a Il borgo che offre la chiave per l'interprezazione di tutto un filone della tematica sabiana, o alle Fughe, con le quali il poeta vuol esprimere l'essenza del proprio sentire. La poetica delle »figure« e dei »canti« composti negli anni venti, non segnerebbe dunque una conversione di Saba ai »miti della forma«, come inducono a credere anche certe apostrofi del poeta stesso, rna può esser definita solo se vista in funzione dei contenuti che determinano il suo formarsi.

  9. Spin Interference in Rashba 2DEG Systems

    Science.gov (United States)

    Nitta, Junsaku

    The gate controllable SOI provides useful information about spin interference.1 Spin interference effects are studied in two different interference loop structures. It is known that sample specific conductance fluctuations affect the conductance in the interference loop. By using array of many interference loops, we carefully pick up TRS Altshuler-Aronov-Spivak (AAS)-type oscillation which is not sample specific and depends on the spin phase. The experimentally obtained gate voltage dependence of AAS oscillations indicates that the spin precession angle can be controlled by the gate voltage.2 We demonstrate the time reversal Aharonov-Casher (AC) effect in small arrays of mesoscopic rings.3 By using an electrostatic gate we can control the spin precession angle rate and follow the AC phase over several interference periods. We also see the second harmonic of the AC interference, oscillating with half the period. The spin interference is still visible after more than 20π precession angle. We have proposed a Stern-Gerlach type spin filter based on the Rashba SOI.4 A spatial gradient of effective magnetic field due to the nonuniform SOI separates spin up and down electrons. This spin filter works even without any external magnetic fields and ferromagnetic contacts. We show the semiconductor/ferromagnet hybrid structure is an effective way to detect magnetization process of submicron magnets. The problem of the spin injection from ferromagnetic contact into 2DEG is also disicussed. Note from Publisher: This article contains the abstract only.

  10. Evaluation of reconstruction arc in myocardial SPECT imaging using a cardiac phantom. Comparison between 360deg and 180deg arcs

    Energy Technology Data Exchange (ETDEWEB)

    Kashikura, Kenichi [Japan Science and Technology Corp., Tokyo (Japan); Kashikura, Akemi; Terada, Shinichirou; Kobayashi, Hideki

    1996-10-01

    In order to investigate the effect of reconstruction arc on myocardial SPECT images, a series of phantom studies was performed with and without plastic chambers simulating perfusion defects using {sup 201}Tl and {sup 99m}Tc. Coefficient of variations (CV) of the counts among the ROIs and defect contrast were evaluated in 360deg and 180deg images reconstructed from the same 360deg projection data. Reconstruction processes were identical for all images. In the absence of defects, the CV of the counts were approximately the same in 360deg and 180deg images. The CV of the counts in the 360deg {sup 201}Tl image, among 4 defects located on the anterior, lateral, inferoposterior, and septal walls, was superior to those in the 180deg images. In contrast, in the {sup 99m}Tc images, the CV of the counts among the 4 defects in the 180deg image was superior to those of the 360deg image. The defect contrast was changed both by the location of the defect and by the reconstruction arc ({sup 201}Tl, {sup 99m}Tc). The defect contrast of the 180deg images, in both {sup 201}Tl and {sup 99m}Tc experiments, was closer to the true contrast value as calculated by the count ratio between myocardium and defect. Although the defect contrast in the anterior, lateral and septal walls was more emphasized in the 180deg images, the defect contrast in the inferoposterior wall was less emphasized in the 180deg images compared to the 360deg ({sup 201}Tl, {sup 99m}Tc). (author)

  11. The tilt illusion: phenomenology and functional implications.

    Science.gov (United States)

    Clifford, Colin W G

    2014-11-01

    The perceived orientation of a line or grating is affected by the orientation structure of the surrounding image: the tilt illusion. Here, I offer a selective review of the literature on the tilt illusion, focusing on functional aspects. The review explores the merits of mechanistic accounts of the tilt illusion based upon sensory gain control in which neuronal responses are normalized by the pooled activity of other units. The role of inhibition between orientation-selective neurons is discussed, and it is argued that their associated disinhibition must also be taken into account in order to model the full angular dependence of the tilt illusion on surround orientation. Parallels are drawn with adaptation as modulation by the temporal rather than spatial context within which an image fragment is processed. The chromatic selectivity of the tilt illusion and the extent of its dependence on the visibility of the surround are used to infer characteristics of the neuronal normalization pools and the loci in the cortical processing hierarchy at which gain control operates. Finally, recent evidence is discussed as to the possible clinical relevance of the tilt illusion as a biomarker for schizophrenia.

  12. The structures of Arabidopsis Deg5 and Deg8 reveal new insights into HtrA proteases

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei [Chinese Academy of Sciences, 5 Datun Road, Chaoyang District, Beijing 100101 (China); University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049 (China); Gao, Feng [Chinese Academy of Sciences, 5 Datun Road, Chaoyang District, Beijing 100101 (China); Fan, Haitian; Shan, Xiaoyue [Chinese Academy of Sciences, 5 Datun Road, Chaoyang District, Beijing 100101 (China); University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049 (China); Sun, Renhua [Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093 (China); University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049 (China); Liu, Lin, E-mail: liulin@ibcas.ac.cn [Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093 (China); Gong, Weimin, E-mail: liulin@ibcas.ac.cn [Chinese Academy of Sciences, 5 Datun Road, Chaoyang District, Beijing 100101 (China)

    2013-05-01

    The crystal structures of Arabidopsis Deg5 and Deg8 have been determined to resolutions of 2.6 and 2.0 Å, respectively, revealing novel structural features of HtrA proteases. Plant Deg5 and Deg8 are two members of the HtrA proteases, a family of oligomeric serine endopeptidases that are involved in a variety of protein quality-control processes. These two HtrA proteases are located in the thylakoid lumen and participate in high-light stress responses by collaborating with other chloroplast proteins. Deg5 and Deg8 degrade photodamaged D1 protein of the photosystem II reaction centre, allowing its in situ replacement. Here, the crystal structures of Arabidopsis thaliana Deg5 (S266A) and Deg8 (S292A) are reported at 2.6 and 2.0 Å resolution, respectively. The Deg5 trimer contains two calcium ions in a central channel, suggesting a link between photodamage control and calcium ions in chloroplasts. Previous structures of HtrA proteases have indicated that their regulation usually requires C-terminal PDZ domain(s). Deg5 is unique in that it contains no PDZ domain and the trimeric structure of Deg5 (S266A) reveals a novel catalytic triad conformation. A similar triad conformation is observed in the hexameric structure of the single PDZ-domain-containing Deg8 (S292A). These findings suggest a novel activation mechanism for plant HtrA proteases and provide structural clues to their function in light-stress response.

  13. Neutron irradiation of silicon diodes at temperatures of +20deg C and -20deg C

    Energy Technology Data Exchange (ETDEWEB)

    Anghinolfi, F.; Glaser, M.; Heijne, E.H.M.; Jarron, P.; Lemeilleur, F.; Occelli, E.; Poppleton, A. (CERN, Geneva (Switzerland)); Bardos, R.; Gorfine, G.; Moorhead, G.; Taylor, G.; Tovey, S. (School of Physics, Univ. Melbourne, Parkville (Australia)); Bates, S.J.; Munday, D.J.; Parker, M.A. (Cavendish Lab., Univ. Cambridge (United Kingdom)); Bonino, R.; Clark, A.G.; Wu, X. (DPNC, Univ. Geneva (Switzerland)); Claussen, N.; Fretwurst, E.; Lindstroem, G.; Papendick, B.; Schulz, T.; Wunstorf, R. (Inst. fuer Experimentalphysik, Univ. Hamburg (Germany)); Goessling, C.; Klingenberg, R.; Pagel, H.; Pollmann, D.; Rolf, A. (Inst. fuer Physik, Univ. Dortmund (Germany)); Scampoli, P. (Dipt. di Fisica, Univ. Perugia (Italy) INFN, Sezione Perugia (Italy)); Weidberg, A.R. (Dept. of Nuclear Physics, Oxford Univ. (United Kingdom)); RD2 Collaboration

    1993-03-01

    We report measurements of the behaviour of silicon diodes when exposed to integrated neutron doses of up to 5x10[sup 13] neutrons/cm[sup 2]. The measurements have been made at diode temperatures between room temperature and -20deg C. From measurements of the diode leakage current and depletion voltage, and consequent evaluations of the effective impurity concentration, the temperature dependence of these quantities is discussed in terms of the annealing behaviour of the diodes. Comments are made on the suitability of silicon as a detector medium for particle physics experiments at future accelerators. (orig.).

  14. DegP Chaperone Suppresses Toxic Inner Membrane Translocation Intermediates

    Science.gov (United States)

    Braselmann, Esther; Chaney, Julie L.; Champion, Matthew M.

    2016-01-01

    The periplasm of Gram-negative bacteria includes a variety of molecular chaperones that shepherd the folding and targeting of secreted proteins. A central player of this quality control network is DegP, a protease also suggested to have a chaperone function. We serendipitously discovered that production of the Bordetella pertussis autotransporter virulence protein pertactin is lethal in Escherichia coli ΔdegP strains. We investigated specific contributions of DegP to secretion of pertactin as a model system to test the functions of DegP in vivo. The DegP chaperone activity was sufficient to restore growth during pertactin production. This chaperone dependency could be relieved by changing the pertactin signal sequence: an E. coli signal sequence leading to co-translational inner membrane (IM) translocation was sufficient to suppress lethality in the absence of DegP, whereas an E. coli post-translational signal sequence was sufficient to recapitulate the lethal phenotype. These results identify a novel connection between the DegP chaperone and the mechanism used to translocate a protein across the IM. Lethality coincided with loss of periplasmic proteins, soluble σE, and proteins regulated by this essential stress response. These results suggest post-translational IM translocation can lead to the formation of toxic periplasmic folding intermediates, which DegP can suppress. PMID:27626276

  15. DegP Chaperone Suppresses Toxic Inner Membrane Translocation Intermediates.

    Science.gov (United States)

    Braselmann, Esther; Chaney, Julie L; Champion, Matthew M; Clark, Patricia L

    2016-01-01

    The periplasm of Gram-negative bacteria includes a variety of molecular chaperones that shepherd the folding and targeting of secreted proteins. A central player of this quality control network is DegP, a protease also suggested to have a chaperone function. We serendipitously discovered that production of the Bordetella pertussis autotransporter virulence protein pertactin is lethal in Escherichia coli ΔdegP strains. We investigated specific contributions of DegP to secretion of pertactin as a model system to test the functions of DegP in vivo. The DegP chaperone activity was sufficient to restore growth during pertactin production. This chaperone dependency could be relieved by changing the pertactin signal sequence: an E. coli signal sequence leading to co-translational inner membrane (IM) translocation was sufficient to suppress lethality in the absence of DegP, whereas an E. coli post-translational signal sequence was sufficient to recapitulate the lethal phenotype. These results identify a novel connection between the DegP chaperone and the mechanism used to translocate a protein across the IM. Lethality coincided with loss of periplasmic proteins, soluble σE, and proteins regulated by this essential stress response. These results suggest post-translational IM translocation can lead to the formation of toxic periplasmic folding intermediates, which DegP can suppress.

  16. Tilts of the Master Equatorial Tower

    Science.gov (United States)

    Ahlstrom, H. G., Jr.; Gawronski, W.; Girdner, D.; Noskoff, E.; Sommerville, J. N.

    2000-07-01

    At the center of the DSS-14 antenna, a tower reaches to the focal point of the antenna dish. The master equatorial (ME) instrument is located at the top of the tower. This instrument precisely (with an accuracy that exceeds that of the antenna) follows the commanded trajectory. Through the optical coupling, the antenna focal point follows the ME. One factor of the antenna pointing precision is the movement of the ME base, i.e., the top of the tower. For this reason, measurements of the ME tower tilts have been taken in order to quantify the tilts, to determine possible causes of the tilting, and to update the antenna pointing budget. They were conducted under three antenna operating modes: during tracking, slewing, and antenna stowing. The measurements indicate that the ME tower tilts introduce significant pointing errors that exceed the required 32-GHz (Ka-band) pointing precision (estimated as 0.8 mdeg for a 0.1-dB gain loss). Four different sources of tilt were identified and require verification.

  17. The functional benefits of tilt adaptation.

    Science.gov (United States)

    Kristjánsson, Árni

    2011-01-01

    Many have argued that effects of adaptation, such as aftereffects from motion or tilt, reflect that the visual system hones its responses in on the characteristics of the adapting stimulus. This view entails that on average, the discrimination of the characteristics of an adapting stimulus should become easier as viewing time increases since the variation in the response gradually adapts to the range and variation in the stimulus. Here this was tested for adaptation to tilt. Observers viewed a Gabor patch which varied in contrast from 0 to 74% at a rate of 0.6 Hz, for 4, 8, 16 or 32 s, after which the Gabor patch changed orientation (at the point when contrast was 0). The results show that the longer the observers adapt to the dynamic Gabor, the better they become at discriminating between clockwise (CW) or counterclockwise (CCW) changes in tilt (orientation) of the same patch. Experiment 2 confirms that both the direct and indirect tilt aftereffects are seen with this contrast varying Gabor patch and Experiment 3 shows that the aftereffects are only slightly smaller than in other studies with stimuli such as lines and sinusoidal gratings. These results show that adaptation to tilt leads to better discrimination around the orientation of the adapting stimulus itself, and that discrimination performance improves steadily with increased adaptation time. The results support proposals that the visual system adjusts its response characteristics to the properties of the visual input at a given time.

  18. Involvement of DEG5 and DEG8 proteases in the turnover of the photosystem II reaction center D1 protein under heat stress in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    SUN XuWu; WANG LiYuan; ZHANG LiXin

    2007-01-01

    Deg5,deg8 and the double mutant,deg5deg8 of Arabidopsis thaliana were used to study the physiological role of the DEG proteases in the repair cycle of photosystem II (PSII) under heat stress. PSII activity in deg mutants showed increased sensitivity to heat stress,and the extent of this effect was greater in the double mutant,deg5deg8,than in the single mutants,deg5 and deg8. Degradation of the D1 protein was slower in the mutants than in the WT plants. Furthermore,the levels of other PSII reaction center proteins tested remained relatively stable in the mutant and WT plants following high-temperature treatment. Thus,our results indicate that DEG5 and DEG8 may have synergistic function in degradation of D1 protein under heat stress.

  19. The Prevalence of the 22 deg Halo in Cirrus Clouds

    Science.gov (United States)

    Diedenhoven, vanBastiaan

    2014-01-01

    Halos at 22 deg from the sun attributed to randomly-orientated, pristine hexagonal crystals are frequently observed through ice clouds. These frequent sightings of halos formed by pristine crystals pose an apparent inconsistency with the dominance of distorted, nonpristine ice crystals indicated by in situ and remote sensing data. Furthermore, the 46 deg halo, which is associated with pristine hexagonal crystals as well, is observed far less frequently than the 22 deg halo. Considering that plausible mechanisms that could cause crystal distortion such as aggregation, sublimation, riming and collisions are stochastic processes that likely lead to distributions of crystals with varying distortion levels, here the presence of the 22 deg and 46 deg halo features in phase functions of mixtures of pristine and distorted hexagonal ice crystals is examined. We conclude that the 22 deg halo feature is generally present if the contribution by pristine crystals to the total scattering cross section is greater than only about 10% in the case of compact particles or columns, and greater than about 40% for plates. The 46 deg halo feature is present only if the mean distortion level is low and the contribution of pristine crystals to the total scattering cross section is above about 20%, 50% and 70%, in the case of compact crystals, plates and columns, respectively. These results indicate that frequent sightings of 22 deg halos are not inconsistent with the observed dominance of distorted, non-pristine ice crystals. Furthermore, the low mean distortion levels and large contributions by pristine crystals needed to produce the 461 halo features provide a potential explanation of the common sighting of the 22 deg halo without any detectable 46 deg halo.

  20. Advances in tilt rotor noise prediction

    Science.gov (United States)

    George, A. R.; Coffen, C. D.; Ringler, T. D.

    The two most serious tilt rotor external noise problems, hover noise and blade-vortex interaction noise, are studied. The results of flow visualization and inflow velocity measurements document a complex, recirculating highly unsteady and turbulent flow due to the rotor-wing-body interactions characteristic of tilt rotors. The wing under the rotor is found to obstruct the inflow, causing a deficit in the inflow velocities over the inboard region of the rotor. Discrete frequency harmonic thickness and loading noise mechanisms in hover are examined by first modeling tilt rotor hover aerodynamics and then applying various noise prediction methods using the WOPWOP code. The analysis indicates that the partial ground plane created by the wing below the rotor results in a primary sound source for hover.

  1. The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b

    CERN Document Server

    Winn, Joshua N; Johnson, John Asher; Marcy, Geoffrey W; Gazak, J Zachary; Starkey, Donn; Ford, Eric B; Colon, Knicole D; Reyes, Francisco; Nortmann, Lisa; Dreizler, Stefan; Odewahn, Stephen; Welsh, William F; Kadakia, Shimonee; Vanderbei, Robert J; Adams, Elisabeth R; Lockhart, Matthew; Crossfield, Ian J; Valenti, Jeff A; Dantowitz, Ronald; Carter, Joshua A

    2009-01-01

    We present the results of a pan-American campaign to observe the 2009 June 5 transit of the exoplanet HD 80606b. We report the first detection of the transit ingress, revealing the transit duration to be 11.64 +/- 0.25 hr and allowing more robust determinations of the system parameters. Keck spectra obtained at midtransit exhibit an anomalous blueshift, giving definitive evidence that the stellar spin axis and planetary orbital axis are misaligned. The Keck data show that the projected spin-orbit angle is between 32-87 deg with 68.3% confidence and between 14-142 deg with 99.73% confidence. Thus the orbit of this planet is not only highly eccentric (e=0.93), but is also tilted away from the equatorial plane of its parent star. A large tilt had been predicted, based on the idea that the planet's eccentric orbit was caused by the Kozai mechanism. Independently of the theory, it is noteworthy that all 3 exoplanetary systems with known spin-orbit misalignments have massive planets on eccentric orbits, suggesting ...

  2. La formazione iniziale degli insegnanti in Italia

    Directory of Open Access Journals (Sweden)

    Carlo Cappa

    2013-07-01

    Full Text Available L’articolo è diviso in tre parti. La prima presenta gli elementi storici e di sfondo che occorre tenere presenti per comprendere l’evoluzione della formazione iniziale degli insegnanti verso gli attuali modelli, che pur essendo oggi tutti gestiti dalle università conservano una sensibile diversità a seconda che si tratti di formare maestri per la scuola dell’infanzia e primaria oppure professori di scuola secondaria di primo e secondo grado. La seconda parte analizza il passaggio, maturato tra la fine del secolo scorso e l’inizio del XXI secolo, della formazione dei maestri dalla scuola secondaria (Istituto magistrale all’università (Corso di laurea in Scienze della formazione primaria, e l’istituzione delle Scuole di Specializzazione per l’Insegnamento Secondario (SSIS fino alla soppressione di queste ultime, avvenuta nel 2009. La terza parte presenta il quadro attuale della formazione iniziale dei docenti in Italia con riguardo soprattutto agli insegnanti della scuola secondaria, per i quali – a differenza che per i maestri - sono intervenute dal 2010 importanti innovazioni legislative. Le SSIS sono state infatti sostituite con il Tirocinio Formativo Attivo (TFA, attualmente in fase di attuazione da parte delle università. Nella parte finale dell’articolo si traccia un primo bilancio dell’esperienza del TFA e si indicano alcuni problemi aperti. Il focus rimane sostanzialmente sulla formazione iniziale, in quanto in Italia la formazione in servizio, che pure non è del tutto assente, non è mai stata oggetto di una normativa né di una azione organica, ma avviene, quando avviene, sulla base di iniziative di specifici gruppi o associazioni.The article is organised in three parts. The first one illustrates the historical features and the institutional and political background that have to be taken into account in order to understand how initial teacher education and training has developed in Italy. Presently, all teacher

  3. A Construction of Characteristic Tilting Modules

    Institute of Scientific and Technical Information of China (English)

    DENG Bang Ming

    2002-01-01

    Associated with each finite directed quiver Q is a quasi-hereditary algebra, the so-calledtwisted double of the path algebra kQ. Characteristic tilting modules over this class of quasi-hereditaryalgebras are constructed. Their endomorphism algebras are explicitly described. It turns out that thisclass of quasi-hereditary algebras is closed under taking the Ringel dual.

  4. "Happiness and Education": Tilting at Windmills?

    Science.gov (United States)

    Verducci, Susan

    2013-01-01

    This essay explores the question: Is Nel Noddings a visionary who sees past the constraints of contemporary education or is she, like Don Quixote, madly tilting at windmills in her description and defense of happiness as an educational aim? Viewing the educational aim of happiness as an ideal raises substantial challenges for the practicality of…

  5. "Happiness and Education": Tilting at Windmills?

    Science.gov (United States)

    Verducci, Susan

    2013-01-01

    This essay explores the question: Is Nel Noddings a visionary who sees past the constraints of contemporary education or is she, like Don Quixote, madly tilting at windmills in her description and defense of happiness as an educational aim? Viewing the educational aim of happiness as an ideal raises substantial challenges for the practicality of…

  6. Listening talkers produce great spectral tilt contrasts

    DEFF Research Database (Denmark)

    Christiansen, Thomas Ulrich; Heegård, Jan; Henrichsen, Peter Juel

    of colored geometrical shapes taken from DanPASS [2]. The spectral tilt was gauged by calculating the band-level difference in dB between two frequency bands with pass-bands 150 to 803 Hz and 803 to 1358 Hz respectively in 5 ms intervals. This was done separately for intervals containing content words...

  7. determination of determination of optimal tilt angle for maximum ...

    African Journals Online (AJOL)

    eobe

    Keywords: Energy output, photovoltaic module, best tilt angle, solar radiation, sunshine hours, ambient temperature. 1. .... at any given time is vital in the design of a PV system. ..... Panels at Different Temperatures and Tilt Angles,”. ISESCO ...

  8. Effects of 15 d -6° Head-down Bed Rest on Inhibition Function of Female Subjects.%15d-6°头低位卧床对女性抑制功能的影响

    Institute of Scientific and Technical Information of China (English)

    姚茹; 赵鑫; 王林杰; 谈诚; 周仁来

    2011-01-01

    Objective To study the influence of -6° head-down bed rest (HDBR) on inhibition function of female subjects.Methods The subjects were separated into 2 groups:the experiment group with HDBR and the control group without it.Changes of inhibition function were tested by numerical Stroop task on 5 days before HDBR, during HDBR (5th,10th) and after HDBR (5th day) and the emotional changes of depression and anxiety were recorded by BAI and BDI at the same time.Results Inhibition function was remarkably impaired on the 5th day of HDBR and then recovered to the level of pre-HDBR on the loth day of HDBR.After HDBR, we also found no differences on the promotion of inhibition function between HDBR group and control.Moreover, for HDBR group, the analysis of BAI showed the similar trend of changing from impairment to recovery, although their emotions of anxiety and depression were at normal level.Conclusion We have found obvious dynamic effects of HDBR on inhibition function of female subjects, which is from impairment to recovery.%目的 探讨-6°头低位卧床模拟失重对女性抑制能力的影响.方法 志愿者分为接受头低位卧床实验的卧床组和不参加卧床的对照组,采用数字Stroop任务测试两组志愿者在卧床实验前5天、卧床第5天、卧床第10天以及卧床后第5天的抑制能力,并采用贝克焦虑量表和Beek抑郁量表同步记录各测试时间点志愿者的抑郁和焦虑情绪.结果 卧床第5天,卧床组的抑制功能明显下降,到卧床第10天恢复到卧床前的基线水平并与对照组持平,卧床结束后抑制能力继续提高且与对照组无差异.卧床并未诱发卧床组明显的焦虑和抑郁情绪,但卧床组的焦虑量表得分也表现出同样的损害一恢复趋势.结论 头低位卧床对女性抑制功能的影响表现为由损害到恢复的发展变化过程.

  9. 女性15d头低位卧床实验的组织实施与医学监督%15 d Head-down Bed Rest of Female Subjects: Practice Overview and Medical Monitoring.

    Institute of Scientific and Technical Information of China (English)

    王林杰; 窦跃龙; 李莹辉; 白延强; 张丽芬; 李志利; 杨鸿慧; 王惠娟; 陈文娟; 唐国华; 王峻; 周湘杰

    2011-01-01

    Head-down Bed Rest(HDBR) experiment is an important ground-based analog to make up for the limited resources aboard space station for human research. And female HDBR experiment develops as an primary platform to explore the countermeasures for female astronaut. Astronaut Center of China(ACC) organized the 15 d HDBR experiment of female subjects to evaluate, compare and refine female countermeasure in weightlessness. This paper serves as an overview and describes the experiment control, test item, test time points,etc. Detailed results form multiple-disciplines are presented in a series of reports. Heart rates (HR)decreased during bed rest and diastolic pressure(DSP) dropped at the later period of bed rest. The water balance during bed rest was at the same level as that in pre- and post-bed rest. the data presented in this paper served as a context in which to view the data presented in manuscripts about cardiovascular and muscle system changes. The dietary support, basic cognitive function and stomatology information regarding those aspects of implementing bed rest studies successfully and results from non-targeted system.%头低位卧床实验(HDBR)是弥补在轨飞行资源限制的重要地面模拟途径.女性头低位卧床实验是探索我国女性航天员参与航天飞行任务防护方法的重要平台.中国航天员中心组织实施了女性15 d头低位卧床实验,用于评价、比较和改进失重生理效应的防护方法.本文介绍了实验概况,志愿者的选拔情况,卧床实验控制、测试项目和测试时间等.卧床过程中志愿者心率降低,卧床后期舒张压降低,卧床期间静摄水量与卧床前后基本持平.卧床实验的多项结果在本刊的系列文章中给出.本文中的数据是本刊其他关于心血管和肌肉系统文章的基本背景.营养供给、基本认知功能和口腔相关研究结果是成功组织本实验和非靶研究系统的结果.

  10. A tilted transversely isotropic slowness surface approximation

    KAUST Repository

    Stovas, A.

    2012-05-09

    The relation between vertical and horizontal slownesses, better known as the dispersion relation, for transversely isotropic media with a tilted symmetry axis (TTI) requires solving a quartic polynomial equation, which does not admit a practical explicit solution to be used, for example, in downward continuation. Using a combination of the perturbation theory with respect to the anelliptic parameter and Shanks transform to improve the accuracy of the expansion, we develop an explicit formula for the vertical slowness that is highly accurate for all practical purposes. It also reveals some insights into the anisotropy parameter dependency of the dispersion relation including the low impact that the anelliptic parameter has on the vertical placement of reflectors for a small tilt in the symmetry angle. © 2012 European Association of Geoscientists & Engineers.

  11. Ram pressure stripping of tilted galaxies

    CERN Document Server

    Jachym, P; Palous, J; Combes, F

    2009-01-01

    Ram pressure stripping of galaxies in clusters can yield gas deficient disks. Previous numerical simulations based on various approaches suggested that, except for near edge-on disk orientations, the amount of stripping depends very little on the inclination angle. Following our previous study of face-on stripping, we extend the set of parameters with the disk tilt angle and explore in detail the effects of the ram pressure on the interstellar content (ISM) of tilted galaxies that orbit in various environments of clusters, with compact or extended distributions of the intra-cluster medium (ICM). We further study how results of numerical simulations could be estimated analytically. A grid of numerical simulations with varying parameters is produced using the tree/SPH code GADGET with a modified method for calculating the ISM-ICM interaction. These SPH calculations extend the set of existing results obtained from different codes using various numerical techniques. The simulations confirm the general trend of le...

  12. Estimating Insolation Incident on Tilted Surfaces

    Science.gov (United States)

    Elkin, R. E.; Toelle, R. G.

    1983-01-01

    ASHMET computer program estimates amount of solar insolation incident on surfaces of several types of solar collectors, including fixed-position flat-plate, monthly-tilt-adjusted flat-plat, beam-tracting, and fixed-azimuthtracker. Basic methodology employed in ASHMET is to use ASHRAE relationships to obtain clear-day total daily insolation incident on collector surface of representative day of each month of year. ASHMET is interactive program and prompts user for all required data.

  13. Dry tilt network at Mount Rainier, Washington

    Science.gov (United States)

    Dzurisin, Daniel; Johnson, Daniel J.; Symonds, R.B.

    1984-01-01

    In addition to its primary responsibility of monitoring active Mount St. Helens, the David A. Johnston Cascades Volcano Observatory (CVO) has been charged with obtaining baseline geodetic and geochemical information at each of the other potentially active Cascade volcanoes. Dry tilt and/or trilateration networks were established during 1975-82 at Mount Baker, Mount St. Helens, Mount Hood, Mount Shasta, Lassen Peak, Crater Lake, and Long Valley caldera; coverage was extended during September 1982 to include Mount Rainier.

  14. Alleviation of whirl-flutter on a joined-wing tilt-rotor aircraft configuration using active controls

    Science.gov (United States)

    Vanaken, Johannes M.

    1991-01-01

    The feasibility of using active controls to delay the onset of whirl-flutter on a joined-wing tilt rotor aircraft was investigated. The CAMRAD/JA code was used to obtain a set of linear differential equations which describe the motion of the joined-wing tilt-rotor aircraft. The hub motions due to wing/body motion is a standard input to CAMRAD/JA and were obtained from a structural dynamics model of a representative joined-wing tilt-rotor aircraft. The CAMRAD/JA output, consisting of the open-loop system matrices, and the airframe free vibration motion were input to a separate program which performed the closed-loop, active control calculations. An eigenvalue analysis was performed to determine the flutter stability of both open- and closed-loop systems. Sensor models, based upon the feedback of pure state variables and based upon hub-mounted sensors, providing physically measurable accelerations, were evaluated. It was shown that the onset of tilt-rotor whirl-flutter could be delayed from 240 to above 270 knots by feeding back vertical and span-wise accelerations, measured at the rotor hub, to the longitudinal cyclic pitch. Time response calculations at a 270-knot cruise condition showed an active cyclic pitch control level of 0.009 deg, which equates to a very acceptable 9 pound active-control force applied at the rotor hub.

  15. Tilt, Warp, and Simultaneous Precessions in Disks

    CERN Document Server

    Montgomery, M M

    2012-01-01

    Warps are suspected in disks around massive compact objects. However, the proposed warping source -- non-axisymmetric radiation pressure -- does not apply to white dwarfs. In this letter we report the first Smoothed Particle Hydrodynamic simulations of accretion disks in SU UMa-type systems that naturally tilt, warp, and simultaneously precess in the prograde and retrograde directions using white dwarf V344 Lyrae in the Kepler field as our model. After ~79 days in V344 Lyrae, the disk angular momentum L_d becomes misaligned to the orbital angular momentum L_o. As the gas stream remains normal to L_o, hydrodynamics (e.g., the lift force) is a likely source to disk tilt. In addition to tilt, the outer disk annuli cyclically change shape from circular to highly eccentric due to tidal torques by the secondary star. The effect of simultaneous prograde and retrograde precession is a warp of the colder, denser midplane as seen along the disk rim. The simulated rate of apsidal advance to nodal regression per orbit ne...

  16. Tilting of a Disk of Gravitating Rings

    CERN Document Server

    Lovelace, R V E

    1997-01-01

    The present work represents an attempt to understand the `rules of behavior' of observed warps in the HI disks of spiral galaxies found by Briggs (1990). In contrast with most earlier theoretical work, the present study investigates different initial value problems of a warped disk in an oblate (or prolate) halo potential, and it represents the disk warp in terms of $N$ independently tilted, self-gravitating, concentric rings. This representation gives new insight into the disk warping. A new constant of the motion of $N$ tilted rings is identified (in addition to the energy). The phenomenon of phase-locking of the lines-of-nodes of nearby rings due to self-gravity is demonstrated. We consider the influence of dynamical friction due to ring motion through the halo matter as well as friction between gaseous rings with different vertical motions due to turbulent viscosity. We first consider the dynamics of one, two, and three tilted rings of different radii in a halo potential. We go on to develop dynamical equ...

  17. WIYN tip-tilt module performance

    Science.gov (United States)

    Claver, Charles F.; Corson, Charles; Gomez, R. Richard, Jr.; Daly, Philip N.; Dryden, David M.; Abareshi, Behzod

    2003-02-01

    The WIYN Tip-Tilt Module (WTTM) is an addition to the existing Instrument Adapter System (IAS) providing a high performance optical-NIR image stabilized port on the WIYN 3.5m telescope. The WTTM optical system uses a 3-mirror off-axis design along with a high bandwidth tilt mirror. The WTTM is a reimaging system with 15% magnification producing a 4x4 arcminute field of view and near diffraction limited imagery from 400-2000nm. The optics are diamond turned in electroless Nickel over an Aluminum substrate. The WTTM opto-mechanical assembly was designed and built using the principals of the "build-to-print" technique, where the entire system is fabricated and assembled to tolerance with no adjustments. A unique high performance error sensor, using an internal mirrorlette array that feeds 4 fiber coupled avalanche photodiode photon counters, provides the tilt signal. The system runs under the Real-Time Linux operating system providing a maximum closed loop rate of 3khz. In this paper we report on the successful lab testing, verification of the "build-to-print" technique and on telescope performance of the WTTM.

  18. Tilting Saturn without Tilting Jupiter or Ejecting an Ice Giant: Constraints on migration

    Science.gov (United States)

    McNeil, Douglas S.; Lee, M. H.

    2010-10-01

    The obliquities of the giant planets preserve information about their migration and encounter histories. Are the classic Nice models (Tsiganis et al. 2005) or the resonant Nice models (Morbidelli et al. 2007) compatible with Jupiter's 3 degree tilt and Saturn's 27? Here we consider the obliquity evolution of the giants during the planetesimal-driven migration phase using two methods: (1) a purely secular integration of the Laplace-Lagrange equations with spin, and (2) a hybrid N-body scheme with full interactions between the Sun and the giants but imposed prescriptions for migration and eccentricity and inclination damping. We find that it is difficult to reproduce today's obliquity values as migration timescales sufficient to tilt Saturn via the Hamilton & Ward (2004) secular spin-orbit resonance mechanism generally suffice to tilt Jupiter more than is observed. Moreover, long migration timescales which make tilting Saturn easier simultaneously reduce the survival fraction (to below 20% for timescales longer than 20 Myr.) We discuss the constraints these observations provide on the dynamical history of the giant planets, and the remaining possibility of tilting Saturn during a late very slow migration of Neptune to its present location after the main phase of migration is complete. [This work was supported by Hong Kong RGC grant HKU 7024/08P.

  19. The family of Deg/HtrA proteases in plants

    Directory of Open Access Journals (Sweden)

    Schuhmann Holger

    2012-04-01

    Full Text Available Abstract Background The Deg/HtrA family of ATP-independent serine endopeptidases is present in nearly all organisms from bacteria to human and vascular plants. In recent years, multiple deg/htrA protease genes were identified in various plant genomes. During genome annotations most proteases were named according to the order of discovery, hence the same names were sometimes given to different types of Deg/HtrA enzymes in different plant species. This can easily lead to false inference of individual protease functions based solely on a shared name. Therefore, the existing names and classification of these proteolytic enzymes does not meet our current needs and a phylogeny-based standardized nomenclature is required. Results Using phylogenetic and domain arrangement analysis, we improved the nomenclature of the Deg/HtrA protease family, standardized protease names based on their well-established nomenclature in Arabidopsis thaliana, and clarified the evolutionary relationship between orthologous enzymes from various photosynthetic organisms across several divergent systematic groups, including dicots, a monocot, a moss and a green alga. Furthermore, we identified a “core set” of eight proteases shared by all organisms examined here that might provide all the proteolytic potential of Deg/HtrA proteases necessary for a hypothetical plant cell. Conclusions In our proposed nomenclature, the evolutionarily closest orthologs have the same protease name, simplifying scientific communication when comparing different plant species and allowing for more reliable inference of protease functions. Further, we proposed that the high number of Deg/HtrA proteases in plants is mainly due to gene duplications unique to the respective organism.

  20. Limiting Global Warming to 2 deg C and Beyond

    Science.gov (United States)

    Lea, D. W.

    2011-12-01

    This presentation addresses the question of how feasible is it to limit global warming to a specific temperature rise, whether 1.5, 2 or 3 deg C. Inherent in the idea of limiting global warming to a specific temperature level is the notion that future GHG emissions will be subject to a top-down international agreement. In the post-Copenhagen era, however, such an agreement is unlikely, and a bottoms-up approach of national pledges will likely have to serve as a surrogate for achieving emissions reduction. In this case, an additional question is what temperature targets are realistic under scenarios that are bounded by achievable national pledges as opposed to binding mandates. The question of feasibility depends largely on future emission pathways of CO2, other GHGs, black carbon and aerosols. Those pathways depend on many societal, technological and economic factors, but it is likely that the ultimate limiting factor is the maximum possible rate of absolute emission reduction. That rate is limited by how rapidly energy infrastructure can be turned over. Most studies suggest that an absolute emission reduction rate of 3.5% is the highest rate achievable. Climate sensitivity and the current cooling effect of aerosols and earth system responses such as the rate of ocean heat uptake and carbon cycle feedbacks determine how a specific emissions pathway translates into probable climate change. A useful framework for CO2 alone is provided by the newly emerging paradigm of cumulative emissions, which holds that peak temperature can be largely predicted by the total amount of carbon emitted, regardless of pathway. Most studies suggest that 1 Tt of cumulative carbon is equivalent to ~2 deg of peak warming. A consideration of these factors suggests that limiting warming to 1.5 deg C is no longer possible under any feasible economic scenario. For one, currently emitted GHGs are equivalent to a ~1.3 deg C warming commitment. This leaves very little room for future emissions

  1. Tropospheric ozone over a tropical Atlantic station in the Northern Hemisphere: Paramaribo, Surinam (6 deg N, 55 deg W)

    Energy Technology Data Exchange (ETDEWEB)

    Peters, W.; Krol, M.C. [Inst. for Marine and Atmospheric Research Utrecht (Netherlands); Fortuin, J.P.F.; Kelder, H.M. [Koninklijke Nederlandse Meteorologische Dienst, De Bilt (Netherlands); Thompson, A.M. [Goddard Space Flight Center, NASA, Greenbelt, MD (United States); Becker, C.R. [Meteorologische Dienst Suriname, Paramaribo (Suriname); Lelieveld, J.; Crutzen, P.J. [Max Planck Inst. fuer Chemie, Mainz (Germany)

    2004-02-01

    We present an analysis of 2.5 yr of weekly ozone soundings conducted at a new monitoring station in Paramaribo, Surinam (6 deg N, 55 deg W). This is currently one of only three ozone sounding stations in the Northern Hemisphere (NH) tropics, and the only one in the equatorial Atlantic region. Paramaribo is part of the Southern Hemisphere Additional Ozone Sounding program (SHADOZ). Owing to its position close to the equator, the inter-tropical convergence zone (ITCZ) passes over Paramaribo twice per year, which results in a semi-annual seasonality of many parameters including relative humidity and ozone. The dataset from Paramaribo is used to: (1) evaluate the ozone variability relative to precipitation, atmospheric circulation patterns and biomass burning; (2) contrast ozone at the NH equatorial Atlantic with that at nearby Southern Hemisphere (SH) stations Natal (6 deg S, 35 deg W) and Ascension (8 deg S, 14 deg W); (3) compare the seasonality of tropospheric ozone with a satellite-derived ozone product: tropical tropospheric ozone columns from the modified residual method (MR-TTOC). We find that Paramaribo is a distinctly Atlantic station. Despite its position north of the equator, it resembles nearby SH stations during most of the year. Transport patterns in the lower and middle troposphere during February and March differ from SH stations, which leads to a seasonality of ozone with two maxima. MR-TTOC over Paramaribo does not match the observed seasonality of ozone due to the use of a SH ozone sonde climatology in the MR method. The Paramaribo ozone record is used to suggest an improvement for Northern Hemisphere MR-TTOC retrievals. We conclude that station Paramaribo shows unique features in the region, and clearly adds new information to the existing SHADOZ record.

  2. Analysis of tilt of the Günther Tulip filter.

    Science.gov (United States)

    Sag, Alan A; Stavas, Joseph M; Burke, Charles T; Dixon, Robert G; Marquess, Joel S; Mauro, Matthew A

    2008-05-01

    To determine the frequency, dimensions, predictors, and sequelae of Günther Tulip filter (GTF) tilt measured at the time of intended retrieval. Retrospective review of all medical records and posteroanterior cavograms of 175 patients who underwent both placement and retrieval of the GTF between August 2003 and July 2007 was performed to assess the frequency, dimensions, predictors, and sequelae of tilt. Tilt occurred at the first retrieval attempt in 159 of the 175 patients (91%). The average degree of tilt was 7.1 degrees (range, 0 degrees-30 degrees), with 87 of the 159 filters with tilt (55%) having a rightward tilt. Compared with the femoral approach, filters placed with a jugular approach demonstrated 4.2 degrees (range of the standard deviation, 3.1 degrees-5.3 degrees) greater tilt at the first retrieval attempt (95% confidence interval=2.6 degrees, 5.7 degrees; P<.001, two-sided Student t test), a greater frequency of tilt of at least 14 degrees (P=.002, two-sided Fisher exact test), and greater rightward tilt predominance (P=.046, one-sided Fisher exact test). Tilt magnitude at the first retrieval attempt correlated positively with the inferior vena cava diameter 40 mm caudal to the renal vein confluence (R=.183, P=.018, Pearson correlation). Within its limitations, this study detected no new cases of pulmonary embolism, caval perforation, or GTF migration. The success rates at the first attempt at retrieval and the cumulative GTF retrieval success rates were 93% (176 of 190 filters) and 97% (181 of 190 filters), respectively. All 29 GTFs with tilt of at least 14 degrees were placed and successfully retrieved by means of a jugular approach with minimal clinical and technical sequelae. Frequent GTF tilt detected at the first retrieval attempt can reach at least 14 degrees and is associated with minimal sequelae. Insertion approach and caval diameter are significant factors in GTF tilt.

  3. Magnetic nanocap arrays with tilted magnetization

    Science.gov (United States)

    Albrecht, Manfred

    2009-03-01

    In modern magnetic recording materials the ``superparamagnetic effect'' has become increasingly important as new magnetic hard disk drive products are designed for higher storage densities. In this regard, patterned media [1], where two-dimensional arrays of nanostructures are used, is one of the concepts that might provide the required areal density in future magnetic recording devices. However, also nanostructure arrays will ultimately need high anisotropy material such as L10-FePt to provid enough thermal stability and thus much higher writing fields than currently obtainable from perpendicular magnetic recording heads. One proposed solution to this problem is the use of tilted magnetic recording media [2]. The basic idea is to tilt the easy axis of the magnetic medium from the perpendicular direction to 45 degree. In this case, the switching field will be reduced by a foctor of two in the Stoner-Wohlfarth limit. Recently, this approach was realized by oblique film deposition onto arrays of self-assembled spherical particles [3-5]. In this presentation, recent results on different film systems including Co/Pt multilayers, FePt and CoPtCr-SiO2 alloys which have been deposited onto SiO2 particle monolayers will be presented. It turned out that by tuning the growth conditions single domain nanocaps with enhanced magnetic coercivity and tilted anisostropy axis can be achieved even for particle sizes below 50 nm. [4pt] [1] B. D. Terris and T. Thomson, J. Phys. D: Appl. Phys. 38 (2005) R199 [0pt] [2] J.-P. Wang, Nat. Mater. 4, 191 (2005). [0pt] [3] M. Albrecht et al., Nat. Mater. 4, 203 (2005). [0pt] [4] T. Ulbrich et al., Phys. Rev. Lett. 96 (2006) 077202. [0pt] [5] D. Makarov et al., Appl. Phys. Lett. 93, 153112 (2008).

  4. Tilted foils polarization at REX-ISOLDE

    CERN Document Server

    Tornqvist, H; Yordanov, D T; Imai, N; Heinz, A; Nilsson, T; Sotty, C; Hass, M; Georgiev, G; Johansson, H; Dhal, A; Stuchbery, A; Wenander, F; Hirayama, Y; Kusoglu, A; Balabanski, D

    2013-01-01

    The tilted-foils nuclear-spin polarization method has been evaluated using the REX-ISOLDE linear accelerator at the ISOLDE facility, CERN. A beam of Li-8 delivered with an energy of 300 keV/u traversed through one Mylar foil to degrade the beam energy to 200 keV/u and consequently through 10 thin diamond-like carbon foils to polarize the nuclear spin. The attained nuclear spin polarization of 3.6 +/- 0.3% was measured with a beta-NMR setup. (C) 2013 Elsevier B.V. All rights reserved.

  5. Radio identification of decameter-wave sources. II: The 30degdeg declination interval

    CERN Document Server

    Verkhodanov, O V; Andernach, H; 10.1134/S1990341309010052

    2009-01-01

    This paper is dedicated to the identification of decameter-wave sources of the UTR catalog within declination interval 30degdeg. UTR sources are cross-identified with CATS database catalogs within 40'x40' error boxes. The sources are deblended using the data on the coordinates of the objects and the behavior of their continuum radio spectra. The spectra of 876 sources are derived and fitted by standard analytical functions. Of these sources, 221 objects have straight-line spectra with spectral indices alpha<-1.0. All objects are catalogued and stored in the CATS database.

  6. An efficient eikonal solver for tilted transversely isotropic and tilted orthorhombic media

    KAUST Repository

    Waheed, Umair bin

    2014-01-01

    Computing first-arrival traveltimes in the presence of anisotropy is important for high-end near surface modeling, microseismic source localization, and fractured reservoir characterization. Anisotropy deviating from elliptical anisotropy introduces higher-order nonlinearity into the eikonal equation, which makes solving the equation a challenging task. We address this challenge by iteratively solving a sequence of simpler tilted elliptically anisotropic eikonal equations. At each iteration, the source function is updated to capture the effects due to the higher order nonlinear terms in the anisotropy. We use Aitken extrapolation to speed up the convergence rate of the iterative algorithm. The result is an efficient algorithm for firstarrival traveltime computations in tilted anisotropic media. We demonstrate the proposed method for the tilted transversely isotropic media and the tilted orthorhombic media. Numerical tests show that the proposed method is feasible and produces results that are comparable to wavefield extrapolation, even for strongly anisotropic and complex structures. Therefore, for the cases where one or two-point ray tracing fails, our method may be a potential substitute for computing traveltimes.

  7. Effect of pelvic tilt on lumbar spine geometry.

    Science.gov (United States)

    Delisle, A; Gagnon, M; Sicard, C

    1997-12-01

    The purpose of this study was to use a noninvasive method to determine the effect of pelvic tilt on the lumbar spine geometry in the sagittal plane. Five healthy male subjects were instructed in performing active forward and backward pelvic tilt manoeuvres in the standing position. The lumbar spine geometry (severity of lordosis, pelvis and lumbar vertebrae orientations) was estimated with a lumbar spine geometric model. The voluntary backward pelvic tilt succeeded in reducing the depth of the lumbar spine curvature, but the forward tilt did not change it. Both pelvic tilt manoeuvres influenced the absolute orientations of the lower lumbar vertebrae and the relative orientations of some lumbar vertebrae. Interestingly, the L5/S1 joint showed was little affected by the pelvic tilt manoeuvres.

  8. The deceleration parameter in `tilted' Friedmann universes

    CERN Document Server

    Tsagas, Christos G

    2015-01-01

    Large-scale peculiar motions are believed to reflect the local inhomogeneity and anisotropy of the universe, triggered by the ongoing process of structure formation. As a result, realistic observers do not follow the smooth Hubble flow, but have a peculiar, `tilt', velocity relative to it. Our Local Group of galaxies, in particular, moves with respect to the universal expansion at a speed of roughly 600~km/sec. Relative motion effects are known to interfere with the observations and their interpretation. The strong dipolar anisotropy seen in the the Cosmic Microwave Background, for example, is not a sign of real universal anisotropy, but a mere artifact of our peculiar motion relative to the Hubble flow. With these in mind, we look into the implications of large-scale bulk motions for the kinematics of their associated observers, by adopting a `tilted' Friedmann model. Our aim is to examine whether the deceleration parameter measured in the rest-frame of the bulk flow can differ from that of the actual univer...

  9. INVESTIGATIONS ON OPERATION OF ROTARY TILTING FURNACES

    Directory of Open Access Journals (Sweden)

    S. L. Rovin

    2016-01-01

    Full Text Available Rotary tilting furnace (RTF is a new type of fuel furnaces, that provide the most efficient heating and recycling of polydisperse materials. The paper describes results of the investigations on thermal processes in the RTF, movement of materials and non-isothermal gas flow during kiln rotary process. The investigations have been carried out while using physical and computer simulations and under actual operating conditions applying the pilot plant. Results of the research have served as a basis for development of recommendations on the RTF calculations and designing and they have been also used for constructional design of a rotary tilting furnace for heating and melting of cast iron chips, reduction smelting of steel mill scale, melting of aluminum scrap, melting of lead from battery scrap. These furnaces have a high thermal efficiency (~50 %, technological flexibility, high productivity and profitability. Proven technical solutions for recycling of ferrous and non-ferrous metals develop the use of RTF in the foundry and metallurgical industry as the main technological unit for creation of cost-effective small-tonnage recycling of metal waste generated at the plants. The research results open prospects for organization of its own production for high-quality charging material in Belarus in lieu of imported primary metal. The proposed technology makes it possible to solve environmental challenge pertaining to liquidation of multi-tonnage heaps of metal-containing wastes.

  10. Thermal coupling of conjugate ionospheres and the tilt of the earth's magnetic field

    Science.gov (United States)

    Richards, P. G.; Torr, D. G.

    1986-01-01

    The effect of thermal coupling and the tilt of the earth's magnetic field on interhemispheric coupling is investigated, and, due to a longitudinal displacement in the conjugate points, it is found that the tilt significantly effects the upward flow of H(+) flux such that the maximum upward flux can occur several hours before local sunrise. Heating from the conjugate atmosphere, which accompanies solar illumination in one hemisphere, produces electron temperatures 1000 K higher in the dark than in the sunlit hemisphere, and the morning upward H(+) fluxes in the dark ionosphere are as large as the daytime fluxes. A strong symmetry is also noted in the overall behavior of the H(+) fluxes due to the differing day lengths at the conjugate points, which are separated by 15 deg in latitude. Electron temperatures in the conjugate hemispheres are found to be strongly coupled above the F region peaks, though in the vicinity of the peaks near 250 km, the coupling is weak during the day and strong during the night.

  11. Rotating Shaft Tilt Angle Measurement Using an Inclinometer

    OpenAIRE

    2015-01-01

    This paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendic...

  12. Mapping of moveout in tilted transversely isotropic media

    KAUST Repository

    Stovas, A.

    2013-09-09

    The computation of traveltimes in a transverse isotropic medium with a tilted symmetry axis tilted transversely isotropic is very important both for modelling and inversion. We develop a simple analytical procedure to map the traveltime function from a transverse isotropic medium with a vertical symmetry axis (vertical transversely isotropic) to a tilted transversely isotropic medium by applying point-by-point mapping of the traveltime function. This approach can be used for kinematic modelling and inversion in layered tilted transversely isotropic media. © 2013 European Association of Geoscientists & Engineers.

  13. Study on the vehicle license plate tilt correction

    Institute of Scientific and Technical Information of China (English)

    Li Guihui; Li Yuanjin; Li Lanyou

    2006-01-01

    The shortage of current different approaches of the vehicle license plate(VLP) tilt correction is analyzed in the paper and a new rotary correction method put forward based on the former ways of the VLP tilt correction in the horizontal direction and the vertical direction Owing to the VLP tilt taking place in the vertical direction, the array of the image's pixels of the same column is broken, and even different rows come into being superposition.The VLP tilt taking place in the horizontal direction, by which the array of the image's pixels of the same row broken, and so much as different columns come into being superposition.

  14. Embrittlement of reduced-activation ferritic/martensitic steels irradiated in HFIR at 300 deg. C and 400 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L. E-mail: ku2@ornl.gov; Sokolov, M.A.; Shiba, K.; Miwa, Y.; Robertson, J.P

    2000-12-01

    Miniature tensile and Charpy specimens of four ferritic/martensitic steels were irradiated at 300 deg. C and 400 deg. C in the high flux isotope reactor (HFIR) to a maximum dose of {approx}12 dpa. The steels were standard F82H (F82H-Std), a modified F82H (F82H-Mod), ORNL 9Cr-2WVTa, and 9Cr-2WVTa-2Ni, the 9Cr-2WVTa containing 2% Ni to produce helium by (n,{alpha}) reactions with thermal neutrons. More helium was produced in the F82H-Std than the F82H-Mod because of the presence of boron. Irradiation embrittlement in the form of an increase in the ductile-brittle transition temperature ({delta}DBTT) and a decrease in the upper-shelf energy (USE) occurred for all the steels. The two F82H steels had similar {delta}DBTTs after irradiation at 300 deg. C, but after irradiation at 400 deg. C, the {delta}DBTT for F82H-Std was less than for F82H-Mod. Under these irradiation conditions, little effect of the extra helium in the F82H-Std could be discerned. Less embrittlement was observed for 9Cr-2WVTa steel irradiated at 400 deg. C than for the two F82H steels. The 9Cr-2WVTa-2Ni steel with {approx}115 appm He had a larger {delta}DBTT than the 9Cr-2WVTa with {approx}5 appm He, indicating a possible helium effect.

  15. Modello metodologico per il monitoraggio degli incidenti stradali in Trentino

    Directory of Open Access Journals (Sweden)

    P. Fateh-Moghadam

    2003-05-01

    Full Text Available

    Obiettivi: realizzazione di un’infrastruttura informatica, per l’unificazione tempestiva dei flussi sugli incidenti stradali (ISTAT-ACI e sanitari con la georeferenziazione degli eventi a partire dall’anno 2000.

    Materiali e Metodi: dall’archivio di Trentino emergenza sono stati estratti gli interventi per incidente stradale selezionando la combinazione: descrizione patologica: “traumatismi”, tipologia luogo: “strada”, tipologia incidente. Dai dati di ogni Pronto soccorso è stato costruito un archivio unico contenente il totale degli accessi e sono stati estratti gli accessi per “incidente stradale” e quelli per lesioni accidentali in generale. Dall’archivio SDO si sono selezionati sia i ricoveri con il criterio “3” alla variabile mtraav (=incidente stradale che quelli per traumatismi.

    Nell’ambito del progetto “Metodi informatici predittivi per la mitigazione del rischio da incidenti stradali” (Mitris, finanziato dal Ministero della Salute, è stata realizzata l’immissione tramite interfaccia internet o decodifica automatica dei verbali informatizzati delle Forze dell’ordine, e la contestuale realizzazione di un interfaccia WebGIS
    in grado di visualizzare la localizzazione degli incidenti stradali.

    Risultati: tramite la combinazione “data nascita”,
    “data incidente”, “sesso” è stato eseguito un primo collegamento tra gli archivi. Aggiungendo alla data incidente uno o più giorni, è stato costruito un nuovo archivio PS contenente il 97,4% degli eventi raccolti dalle forze dell’Ordine e contenuti nel data base Mitris. Approccio analogo è stato seguito per il linkage con SDO e 118. Tramite interfaccia WebGIS è stata creata una mappa degli incidenti interrogabile on-line, che oltre alla semplice localizzazione riporta dinamica e esiti con possibilità di produrre statistiche e grafici. Il sistema copre attualmente

  16. Upright perception and ocular torsion change independently during head tilt

    Directory of Open Access Journals (Sweden)

    Amir Kheradmand

    2016-11-01

    Full Text Available We maintain a stable perception of the visual world despite continuous movements of our eyes, head and body. Perception of upright is a key aspect of such orientation constancy. Here we investigated whether changes in upright perception during sustained head tilt were related to simultaneous changes in torsional position of the eyes. We used a subjective visual vertical (SVV task, modified to track changes in upright perception over time, and a custom video method to measure ocular torsion simultaneously. We tested twelve subjects in upright position, during prolonged (~15min lateral head tilts of 20 degrees, and also after the head returned to upright position. While the head was tilted, SVV drifted in the same direction as the head tilt (left tilt: -5.4±1.4 o and right tilt: +2.2±2.1 o. After the head returned to upright position, there was an SVV aftereffect with respect to the pre-tilt baseline, which was also in the same direction as the head tilt (left tilt: -3.9±0.6 o and right tilt: +2.55±1.0 o. Neither the SVV drift nor the SVV aftereffect were correlated with the changes in ocular torsion. Using the Bayesian spatial-perception model we show that the pattern of SVV drift and aftereffect in our results could be explained by a drift and an adaptation in sensory inputs that encode head orientation. The fact that ocular torsion (mainly driven by the otoliths could not account for the perceptual changes suggests that neck proprioception could be the primary source of drift in upright perception during head tilt, and subsequently the aftereffect in upright position.

  17. Immagini dinamiche: appunti per un catalogo degli usi didattici

    Directory of Open Access Journals (Sweden)

    Filippo Bruni

    2013-03-01

    Full Text Available Le immagini dinamiche costituiscono un’importante risorsa per le attività didattiche. A partire da una riflessione storica, si evidenzia in primo luogo l’importanza di un loro uso efficace alla luce della classificazione operata da Clark e Lyons. In secondo luogo si segnalano alcune attività emergenti legate alla documentazione, al digital storytelling e alla formazione degli insegnanti.

  18. Clogging Tranistion in a Tilted Silo

    Science.gov (United States)

    Thomas, Charles; Durian, Douglas

    2010-03-01

    Granular media flow freely from large horizontal holes at the bottom of a container. However, if the hole is too small, or tilted too far from horizontal, a clog will eventually form at the exit and halt the flow. The number of beads which exit before a clog forms follows an exponential distribution. The average of this distribution increases with increasing hole size and with decreasing angle from horizontal, diverging above a critical hole size. We measure these hole sizes at different angles. The critical hole size as a function of angle constitutes the system's phase transition on a clogging phase diagram. In comparison, the hole sizes where the Beverloo equation predicts the flux to vanish are less than half these critical hole sizes.

  19. Technical Note: Using DEG CPCs at upper tropospheric temperatures

    CERN Document Server

    Wimmer, D; Nieminen, T; Duplissy, J; Ehrhart, S; Almeida, J; Rondo, L; Franchin, A; Kreissl, F; Manninen, H E; Kulmala, M; Curtius, J; Petäjä, T

    2014-01-01

    Over the last few years, several Condensation Particle Counters (CPC) capable of measuring in the sub-3 nm size range have been developed. Here we study the performance of Diethylene glycol (DEG) based CPCs at different temperatures during Cosmics Leaving Outdoor Droplets (CLOUD) measurements at CERN. The data shown here is the first set of verification measurements for sub-3 nm CPCs under upper tropospheric temperatures using atmospherically relevant aerosol particles. To put the results in perspective we calibrated the DEG-CPC at room temperature, resulting in a cut-off diameter of 1.4 nm. All diameters refer to mobility equivalent diameters in this manuscript. At upper tropospheric temperatures between −25 °C and −65 °C, we found cut-off sizes in the range of 2.5 and 2.8 nm. Due to low number concentration after size classification, the cut-off diameters have a high uncertainty (±0.3 nm) associated with them. Operating two laminar flow DEG CPCs with different cut-off sizes together with other aeroso...

  20. Perverse equivalences, BB-tilting, mutations and applications

    CERN Document Server

    Ladkani, Sefi

    2010-01-01

    We relate the notions of BB-tilting and perverse derived equivalence at a vertex. Based on these notions, we define mutations of algebras, leading to derived equivalent ones. We present applications to endomorphism algebras of cluster-tilting objects in 2-Calabi-Yau categories and to algebras of global dimension at most 2.

  1. Contravariantly finite subcategories in a tilting torsion class

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The contravariant finiteness of the subcategory consisting of modules with T-dimension not more than 1 in the torsion class induced by a tilting module T is proved under the condition that the projective dimension of the injective hull of the tilting module is not more than one.

  2. Vesicle shape, molecular tilt, and the suppression of necks.

    Science.gov (United States)

    Jiang, Hongyuan; Huber, Greg; Pelcovits, Robert A; Powers, Thomas R

    2007-09-01

    Can the presence of molecular-tilt order significantly affect the shapes of lipid bilayer membranes, particularly membrane shapes with narrow necks? Motivated by the propensity for tilt order and the common occurrence of narrow necks in the intermediate stages of biological processes such as endocytosis and vesicle trafficking, we examine how tilt order inhibits the formation of necks in the equilibrium shapes of vesicles. For vesicles with a spherical topology, point defects in the molecular order with a total strength of +2 are required. We study axisymmetric shapes and suppose that there is a unit-strength defect at each pole of the vesicle. The model is further simplified by the assumption of tilt isotropy: invariance of the energy with respect to rotations of the molecules about the local membrane normal. This isotropy condition leads to a minimal coupling of tilt order and curvature, giving a high energetic cost to regions with Gaussian curvature and tilt order. Minimizing the elastic free energy with constraints of fixed area and fixed enclosed volume determines the allowed shapes. Using numerical calculations, we find several branches of solutions and identify them with the branches previously known for fluid membranes. We find that tilt order changes the relative energy of the branches, suppressing thin necks by making them costly, leading to elongated prolate vesicles as a generic family of tilt-ordered membrane shapes.

  3. Angular momentum projection of tilted axis rotating states

    Energy Technology Data Exchange (ETDEWEB)

    Oi, M.; Onishi, N.; Tajima, N. [Tokyo Univ. (Japan); Horibata, T.

    1998-03-01

    We applied an exact angular momentum projection to three dimensional cranked HFB (3d-CHFB) states. Tilted axis rotating states (TAR) and principal axis rotating states (PAR) are compared. It is shown that TAR is more adequate than PAR for description of the back bending phenomena driven by tilted rotation or wobbling motion. (author)

  4. Book review. La forma degli animali. Adolf Portmann

    Directory of Open Access Journals (Sweden)

    Manuel Graziani

    2013-09-01

    Full Text Available Nel 1931 il biologo Adolf Portmann era già talmente noto a livello internazionale per le sue ricerche da guadagnarsi la cattedra in zoologia nell'università della sua città natale, Basilea, all'età di appena 34 anni. All'attività di docente universitario ha sempre affiancato un'originale riflessione sul significato delle scienze della vita, imponendosi come una delle figure chiave nel dibattito tra biologia teoretica, estetica e antropologia filosofica. La forma degli animali, la sua opera più celebre, si pone al confine tra varie discipline e conserva un grande interesse ancora oggi che il dialogo tra estetica e biologia si è fatto nuovamente intenso. Pubblicata nel 1948 e in forma ampliata nel 1960 (da cui deriva questa prima edizione italiana a cura di Pietro Conte l'opera rappresenta il frutto più maturo delle sue ricerche "interdisciplinari".Un saggio che nasce dall'insoddisfazione nei confronti dei paradigmi scientifici consolidati e che ripropone l'idea morfologica in biologia sulla scorta del pensiero di J. W. Goethe il quale affermava che "tutto ciò che è deve anche dar cenno di sé e mostrarsi". Adolf Portmann è un convinto sostenitore che dalla forma si possano dedurne le complessive caratteristiche interne ed esterne degli animali. Secondo questa prospettiva la peculiare fisionomia dell'organismo dipende dalla congiunzione delle sue parti e dalle loro reciproche funzioni. Tuttavia l'autore non vede nello studio della forma l'alternativa al funzionalismo quanto, piuttosto, il suo necessario bilanciamento come dichiara nell'introduzione: "… per giungere alla conoscenza della vita animale di strade ce ne sono molte, e tutte possono contribuire ad arricchire la nostra esperienza. Questo lavoro si occupa della forma degli animali e si propone di mettere in luce la peculiare natura dell'aspetto visibile. Ci sono persone che si dedicano allo studio degli animali, conoscono moltissime specie, hanno imparato centinaia di nomi e

  5. Geology of the Delta, Escalante, Price, Richfield and Salina 1 deg x 2 deg NTMS quadrangles, Utah

    Science.gov (United States)

    Thayer, P. A.

    1981-11-01

    The National Uranium Resource Evaluation (NURE) program was established to evaluate domestic uranium resources in the continental United States and to identify areas favorable for uranium exploration. The Grand Junction Office of the Department of Energy is responsible for administering the program. The Savannah River Laboratory (SRL) is responsible for hydrogeochemical and stream-sediment reconnaissance (HSSR) of 3.9 million sq km (1,500,000 mi(2)) in 37 eastern and western states. This document provides geologic and mineral resources reports for the Delta, Escalante, Price, Richfield, and Salina 1 deg x 2 deg National Topographic Map Series quadrangles, Utah. The purpose of these reports is to provide background geologic and mineral resources information to aid in the interpretation of NURE geochemical reconnaissance data. Except for the Escalante Quadrangle, each report is accompanied by a geologic map and a mineral locality map (Plates 1-8, in pocket).

  6. Evaluation of models to predict insolation on tilted surfaces

    Science.gov (United States)

    Klucher, T. M.

    1979-01-01

    An empirical study was performed to evaluate the validity of various insolation models which employ either an isotropic or an anisotropic distribution approximation for sky light when predicting insolation on tilted surfaces. Data sets of measured hourly insolation values were obtained over a 6-month period using pyranometers which received diffuse and total solar radiation on a horizontal plane and total radiation on surfaces tilted toward the equator at 37 degrees and 60 degrees angles above the horizon. Data on the horizontal surfaces were used in the insolation models to predict insolation on the tilted surface; comparisons of measured vs calculated insolation on the tilted surface were examined to test the validity of the sky light approximations. It was found that the Liu-Jordan isotropic distribution model provides a good fit to empirical data under overcast skies but underestimates the amount of solar radiation incident on tilted surfaces under clear and partly cloudy conditions.

  7. A single-tilt TEM stereomicroscopy technique for crystalline materials.

    Science.gov (United States)

    McCabe, Rodney J; Misra, Amit; Mitchell, Terence E; Alexander, Kathleen B

    2003-02-01

    A new single-tilt technique for performing TEM stereomicroscopy of strain fields in crystalline materials has been developed. The technique is a weak beam technique that involves changing the value of g and/or s g while tilting across a set of Kikuchi bands. The primary benefit of the technique is it can be used with single-tilt TEM specimen holders including many specialty holders such as in situ straining, heating, and cooling holders. Standard stereo-TEM techniques are almost always limited to holders allowing two degrees of rotational freedom (i.e., double-tilt or tilt/rotation holders). An additional benefit of the new technique is that it eliminates the need to focus with the specimen height control. These advantages make it useful for stereo viewing or for quantitative stereomicroscopy provided necessary consideration is given to errors that may result from the technique.

  8. The tilting rate of the Milky Way's disc

    Science.gov (United States)

    Earp, Samuel W. F.; Debattista, Victor P.; Macciò, Andrea V.; Cole, David R.

    2017-08-01

    We present tilting rates for galaxies comparable to the Milky Way (MW) in a Λ cold dark matter cosmological hydrodynamical simulation, and compare these with the predicted tilting rate detection limit of the Gaia satellite 0.28° Gyr-1. We first identify galaxies with mass comparable to the MW (9 × 1011 ≤ M200 ≤ 1.2 × 1012 M⊙) and consider the tilting rates between z = 0.3 and 0. This sample yields a tilting rate of 7.6° ± 4.5° Gyr-1. We constrain our sample further to exclude any galaxies that have high stellar accretion during the same time. We still find significant tilting, with an average rate of 6.3° Gyr-1. Both subsamples tilt with rates significantly above Gaia's predicted detection limit. We show that our sample of galaxies covers a wide range of environments, including some similar to the MW's. We find galaxies in denser regions tilt with higher rates then galaxies in less dense regions. We also find correlations between the angular misalignment of the hot gas corona and the tilting rate. Gaia is likely to be able to directly measure tilting in the MW. Such a detection will provide an important constraint on the environment of the MW, including the rate of gas cooling on to the disc, the shape and orientation of its dark matter halo, and the mass of the Large Magellanic Cloud. Conversely, failure to detect tilting may suggest the MW is in a very quiet configuration.

  9. A new rat model for studies of hypokinesia and antiorthostasis

    Science.gov (United States)

    Musacchia, X. J.; Deavers, D. R.

    1982-01-01

    A new rat model (suspension and immobilization) is described for induction of hypokinesia and orthostatic manipulations. Hypokinetic responses were comparable to those in prolonged bed rest and weightlessness in humans, body or limb casted and small cage restrained animals. Responses to antiorthostasis (15 to 20 deg head down tilt) in rats were similar to those in neutral bouyancy tests in humans and animals and to those in prolonged bed rest in humans. During seven days of hypokinesia there was an atrophy of the gastrocnemius and increased excretion of urinary nitrogeneous end products. The antiorthostatic (AOH) 15 to 20 deg head down tilt resulted in diuresis, natriuresis and kaliuresis. No comparable responses were observed in orthostatic hypokinetic (OH) rats. Readaptation from AOH and OH occurred during one week recovery in metabolic cage conditions.

  10. Technical Note: Using DEG-CPCs at upper tropospheric temperatures

    Science.gov (United States)

    Wimmer, D.; Lehtipalo, K.; Nieminen, T.; Duplissy, J.; Ehrhart, S.; Almeida, J.; Rondo, L.; Franchin, A.; Kreissl, F.; Bianchi, F.; Manninen, H. E.; Kulmala, M.; Curtius, J.; Petäjä, T.

    2015-07-01

    Over the last few years, several condensation particle counters (CPCs) capable of measuring in the sub-3 nm size range have been developed. Here we study the performance of CPCs based on diethylene glycol (DEG) at different temperatures during Cosmics Leaving OUtdoor Droplets (CLOUD) measurements at CERN. The data shown here are the first set of verification measurements for sub-3 nm CPCs under upper tropospheric temperatures using atmospherically relevant aerosol particles. To put the results in perspective we calibrated the DEG-CPC at room temperature, resulting in a cut-off diameter of 1.4 nm. All diameters refer to mobility equivalent diameters in this paper. At upper tropospheric temperatures ranging from 246.15 K to 207.15 K, we found cut-off sizes relative to a particle size magnifier in the range of 2.5 to 2.8 nm. Due to low number concentration after size classification, the cut-off diameters have a high uncertainty (±0.3 nm) associated with them. Operating two laminar flow DEG-CPCs with different cut-off sizes together with other aerosol instruments, we looked at the growth rates of aerosol population in the CLOUD chamber for particles smaller than 10 nm at different temperatures. A more consistent picture emerged when we normalized the growth rates to a fixed gas-phase sulfuric acid concentration. All of the instruments detected larger growth rates at lower temperatures, and the observed growth rates decreased as a function of temperature, showing a similar trend for all instruments. The theoretical calculations had a similar but much smaller temperature dependency.

  11. Mutations suppressing the loss of DegQ function in Bacillus subtilis (natto) poly-γ-glutamate synthesis.

    Science.gov (United States)

    Do, Thi-Huyen; Suzuki, Yuki; Abe, Naoki; Kaneko, Jun; Itoh, Yoshifumi; Kimura, Keitarou

    2011-12-01

    The degQ gene of Bacillus subtilis (natto), encoding a small peptide of 46 amino acids, is essential for the synthesis of extracellular poly-gamma-glutamate (γPGA). To elucidate the role of DegQ in γPGA synthesis, we knocked out the degQ gene in Bacillus subtilis (natto) and screened for suppressor mutations that restored γPGA synthesis in the absence of DegQ. Suppressor mutations were found in degS, the receptor kinase gene of the DegS-DegU two-component system. Recombinant DegS-His(6) mutant proteins were expressed in Escherichia coli cells and subjected to an in vitro phosphorylation assay. Compared with the wild type, mutant DegS-His(6) proteins showed higher levels of autophosphorylation (R208Q, M195I, L248F, and D250N), reduced autodephosphorylation (D250N), reduced phosphatase activity toward DegU, or a reduced ability to stimulate the autodephosphorylation activity of DegU (R208Q, D249G, M195I, L248F, and D250N) and stabilized DegU in the phosphorylated form. These mutant DegS proteins mimic the effect of DegQ on wild-type DegSU in vitro. Interestingly, DegQ stabilizes phosphorylated DegS only in the presence of DegU, indicating a complex interaction of these three proteins.

  12. Mutations Suppressing the Loss of DegQ Function in Bacillus subtilis (natto) Poly-γ-Glutamate Synthesis ▿ †

    Science.gov (United States)

    Do, Thi-Huyen; Suzuki, Yuki; Abe, Naoki; Kaneko, Jun; Itoh, Yoshifumi; Kimura, Keitarou

    2011-01-01

    The degQ gene of Bacillus subtilis (natto), encoding a small peptide of 46 amino acids, is essential for the synthesis of extracellular poly-gamma-glutamate (γPGA). To elucidate the role of DegQ in γPGA synthesis, we knocked out the degQ gene in Bacillus subtilis (natto) and screened for suppressor mutations that restored γPGA synthesis in the absence of DegQ. Suppressor mutations were found in degS, the receptor kinase gene of the DegS-DegU two-component system. Recombinant DegS-His6 mutant proteins were expressed in Escherichia coli cells and subjected to an in vitro phosphorylation assay. Compared with the wild type, mutant DegS-His6 proteins showed higher levels of autophosphorylation (R208Q, M195I, L248F, and D250N), reduced autodephosphorylation (D250N), reduced phosphatase activity toward DegU, or a reduced ability to stimulate the autodephosphorylation activity of DegU (R208Q, D249G, M195I, L248F, and D250N) and stabilized DegU in the phosphorylated form. These mutant DegS proteins mimic the effect of DegQ on wild-type DegSU in vitro. Interestingly, DegQ stabilizes phosphorylated DegS only in the presence of DegU, indicating a complex interaction of these three proteins. PMID:21965392

  13. The Codice digitale degli archivi veronesi. A research instrument

    Directory of Open Access Journals (Sweden)

    Andrea Brugnoli

    2014-04-01

    Full Text Available The Codice digitale degli archivi veronesi (Verona’s archives digital code ‹http://cdavr.dtesis.univr.it› makes available online the digital reproductions of the documents produced by corporate bodies and family of Verona between the eighth and twelfth century. The framework of the site reflects the current organisation of the archives. A brief description of the circumstances around the creation of each archive, the corporate body or individual responsible for it and its structure is provided. Each archival unit is identified by its key elements: chronological date, name and qualification of the notary, original/copy, main editions.

  14. The Codice digitale degli archivi veronesi. A research instrument

    Directory of Open Access Journals (Sweden)

    Andrea Brugnoli

    2014-04-01

    Full Text Available The Codice digitale degli archivi veronesi (Verona’s archives digital code ‹http://cdavr.dtesis.univr.it› makes available online the digital reproductions of the documents produced by corporate bodies and family of Verona between the eighth and twelfth century. The framework of the site reflects the current organisation of the archives. A brief description of the circumstances around the creation of each archive, the corporate body or individual responsible for it and its structure is provided. Each archival unit is identified by its key elements: chronological date, name and qualification of the notary, original/copy, main editions.

  15. Islam, rappresentanza degli interessi religiosi e diritto comune europeo *

    Directory of Open Access Journals (Sweden)

    Gianfranco Macrì

    2011-03-01

    Full Text Available Contributo destinato alla pubblicazione negli Atti del Convegno: Europa e Islam. Ridiscutere i fondamenti per la disciplina delle libertà religiose, svoltosi a Salerno il 3 dicembre 2007.SOMMARIO: Premessa - 1. La società «reticolare» europea: sistema di governance e valori unificanti - 2. Europa e fenomeno religioso - 3. La sostanza del Trattato di Lisbona e il ruolo delle organizzazioni religiose - 4. Il dibattito interno all’Islam europeo - 5. La Carta dei musulmani d’Europa - 6. La rappresentanza degli interessi religiosi dell’Islam in Europa - Conclusioni.

  16. Classical and quantum mechanics of diatomic molecules in tilted fields.

    Science.gov (United States)

    Arango, Carlos A; Kennerly, William W; Ezra, Gregory S

    2005-05-08

    We investigate the classical and quantum mechanics of diatomic molecules in noncollinear (tilted) static electric and nonresonant linearly polarized laser fields. The classical diatomic in tilted fields is a nonintegrable system, and we study the phase space structure for physically relevant parameter regimes for the molecule KCl. While exhibiting low-energy (pendular) and high-energy (free-rotor) integrable limits, the rotor in tilted fields shows chaotic dynamics at intermediate energies, and the degree of classical chaos can be tuned by changing the tilt angle. We examine the quantum mechanics of rotors in tilted fields. Energy-level correlation diagrams are computed, and the presence of avoided crossings quantified by the study of nearest-neighbor spacing distributions as a function of energy and tilting angle. Finally, we examine the influence of classical periodic orbits on rotor wave functions. Many wave functions in the tilted field case are found to be highly nonseparable in spherical polar coordinates. Localization of wave functions in the vicinity of classical periodic orbits, both stable and unstable, is observed for many states.

  17. Tilt sensor and servo control system for gravitational wave detection

    CERN Document Server

    Cheng, Y; Ju, L; Blair, D G

    2002-01-01

    This paper describes the design of a novel double-flexure two-axis tilt sensor with a tilt readout based on an optical walk-off sensor. The performance of the device has been investigated theoretically and experimentally. The walk-off sensor has demonstrated a sensitivity of 10 sup - sup 1 sup 1 rad Hz sup - sup 1 sup / sup 2 at 1 Hz. The tilt sensor has measured seismic noise approx 10 sup - sup 9 -10 sup - sup 1 sup 0 rad Hz sup - sup 1 sup / sup 2 for frequency in the 2-10 Hz range.

  18. Single and Multiple Phase Shifts Tilted Fiber Bragg Gratings

    Directory of Open Access Journals (Sweden)

    Christophe Caucheteur

    2009-01-01

    Full Text Available The spectral behavior of single and multiple phase shifts tilted fiber Bragg gratings has been experimentally investigated. To this aim, a simple and cost-effective postprocessing technique based on local thermal treatment was used to create arbitrary phase shifts along the tilted grating structure. In particular, UV written tilted fiber Bragg gratings were treated by the electric arc discharge to erase the refractive index modulation in well-defined regions. We demonstrate that these defects give rise to interference pattern for all modes, and thus defect states can be achieved within all the attenuation bands, enabling a simple wavelength independent spectral tailoring of this class of devices.

  19. Zoogeografia storica e attuale dei carnivori e degli ungulati italiani

    Directory of Open Access Journals (Sweden)

    Marco Masseti

    2003-10-01

    Full Text Available Come per la maggior parte degli altri paesi europei, anche l'attuale composizione delle specie a mammiferi italiane si prefigura in gran parte come il risultato della plurima e prolungata azione antropica condotta sull'ambiente naturale. Questa, avviatasi alcuni millenni or sono, condiziona oggi più che mai la ridefinizione degli equilibri ecologici del nostro Paese. All'interno dell'attuale teriofauna terrestre italiana viene segnalata la presenza di 18 specie di carnivori e di 9 artiodattili, che può rivelarsi in alcuni casi come il risultato di acclimatazioni e/o naturalizzazioni di specie esotiche avvenute in cronologie diverse, anche di epoca molto recente. All'interno dei confini biogeografici dell'Italia andrebbero anche annoverate quelle popolazioni del cervo pomellato medio-orientale, Axis axis (Erxleben, 1777, che sono state naturalizzate in epoca storica assai recente in Istria ed in alcune isole del golfo del Quarnaro (Brioni Maggiore, Cherso e Plauno. Considerazioni analoghe potrebbero forse essere condotte anche per la diffusione artificiale di Herpestes auropunctatus Hodgson, 1836, su alcune isole della Croazia. Le specie fitofaghe riferibili ai gruppi tassonomici dei lagomorfi e degli artiodattili, e che vengono convenzionalmente comprese nella categoria della cosiddetta "selvaggina", sono tra quelle che hanno più subito un'alterazione condotta in profondità dei quadri faunistici originari, proprio in virtù dell'interesse economico e culturale che ancora rappresentano. Nel caso particolare di queste specie di interesse venatorio ci troviamo quasi sempre di fronte a popolazioni che sono state sottoposte ad intensa gestione e che hanno subito frequenti estinzioni locali seguite da reiterate reintroduzioni. Attualmente, data l'espansione sia naturale che artificiale degli ecotipi indigeni e di quelli alloctoni, si osserva ormai una sovrapposizione degli areali, per cui sembra piuttosto difficile riuscire in

  20. A tilting approach to ranking influence

    KAUST Repository

    Genton, Marc G.

    2014-12-01

    We suggest a new approach, which is applicable for general statistics computed from random samples of univariate or vector-valued or functional data, to assessing the influence that individual data have on the value of a statistic, and to ranking the data in terms of that influence. Our method is based on, first, perturbing the value of the statistic by ‘tilting’, or reweighting, each data value, where the total amount of tilt is constrained to be the least possible, subject to achieving a given small perturbation of the statistic, and, then, taking the ranking of the influence of data values to be that which corresponds to ranking the changes in data weights. It is shown, both theoretically and numerically, that this ranking does not depend on the size of the perturbation, provided that the perturbation is sufficiently small. That simple result leads directly to an elegant geometric interpretation of the ranks; they are the ranks of the lengths of projections of the weights onto a ‘line’ determined by the first empirical principal component function in a generalized measure of covariance. To illustrate the generality of the method we introduce and explore it in the case of functional data, where (for example) it leads to generalized boxplots. The method has the advantage of providing an interpretable ranking that depends on the statistic under consideration. For example, the ranking of data, in terms of their influence on the value of a statistic, is different for a measure of location and for a measure of scale. This is as it should be; a ranking of data in terms of their influence should depend on the manner in which the data are used. Additionally, the ranking recognizes, rather than ignores, sign, and in particular can identify left- and right-hand ‘tails’ of the distribution of a random function or vector.

  1. The effects of lateral head tilt on ocular astigmatic axis

    Directory of Open Access Journals (Sweden)

    Hamid Fesharaki

    2014-01-01

    Conclusion: Any minimal angle of head tilt may cause erroneous measurement of astigmatic axis and should be avoided during refraction. One cannot rely on the compensatory function of ocular counter-torsion during the refraction.

  2. Reflection loss of laser mode from tilted end mirror

    Energy Technology Data Exchange (ETDEWEB)

    Marcuse, D.

    1989-02-01

    The authors consider the reflection of the lowest order guided TE mode of a slab waveguide from a tilted end mirror. This problem is applicable to injection lasers if the slab is regarded as an effective refractive index approximation of the channel or ridge waveguide of the laser structure. For a mode width of 3 /mu/m, 5% mirror tilt results in reflection losses in excess of 25 dB for modes of 6/mu/m width, 5/sup 0/ mirror tilt causes reflection losses in excess of 45 dB. For small tilt angles the results of this calculation agree with those based on a Gaussian approximation of the guided mode. For larger angles, and hence higher reflection losses, the results depart significantly from the Gaussian approximation.

  3. Tilt of Emerging Bipolar Magnetic Regions on the Sun

    Science.gov (United States)

    Kosovichev, A. G.; Stenflo, J. O.

    2008-12-01

    Magnetic fields emerging from the Sun's interior carry information about the physical processes of magnetic field generation and transport in the convection zone. A statistical analysis of variations of the tilt angle of bipolar magnetic regions during the emergence, observed from SOHO MDI, shows that the systematic tilt with respect to the equator (Joy's law) is established by the middle of the emergence period. This suggests that the tilt is most likely generated below the surface. However, the data do not show evidence of a dependence of the tilt angle on the amount of flux or a relaxation of the bipolar orientation toward the east-west direction, in contrast to the predictions of the rising magnetic flux rope theories.

  4. Observational Signatures of Tilted Black Hole Accretion Disks from Simulations

    CERN Document Server

    Dexter, Jason

    2011-01-01

    Geometrically thick accretion flows may be present in black hole X-ray binaries observed in the low/hard state and in low-luminosity active galactic nuclei. Unlike in geometrically thin disks, the angular momentum axis in these sources is not expected to align with the black hole spin axis. We compute images from three-dimensional general relativistic magnetohydrodynamic simulations of misaligned (tilted) accretion flows using relativistic radiative transfer, and compare the estimated locations of the radiation edge with expectations from their aligned (untilted) counterparts. The radiation edge in the tilted simulations is independent of black hole spin for a tilt of 15 degrees, in stark contrast to the results for untilted simulations, which agree with the monotonic dependence on spin expected from thin accretion disk theory. Synthetic emission line profiles from the tilted simulations depend strongly on the observer's azimuth, and exhibit unique features such as broad "blue wings." Coupled with precession,...

  5. Effect of beam quality on tilt measurement using cyclic interferometer

    Science.gov (United States)

    Pretheesh Kumar, V. C.; Ganesan, A. R.; Joenathan, C.; Somasundaram, U.

    2016-08-01

    Accurate measurement of angles is extremely important in various metrological applications. Interferometry has always been an excellent technique for accurate measurements. Several methods have been proposed for accurate tilt measurement using interferometric techniques. Almost all of them use the Michelson configuration which is extremely sensitive to environmental vibrations and turbulences. We know that a cyclic interferometer is extremely stable. Even though it is not sensitive to displacement changes, it is twice sensitive to tilt compared to that of a Michelson interferometer. We have enhanced the sensitivity to measure tilt using multiple reflections in a cyclic interferometer. Since the input beam is collimated, we have studied the effect of aberration of the input beam on the accuracy of tilt measurement. Experimental results on this study are presented in this paper.

  6. Dynamic UCLA for single tilted implant in an aesthetic region

    National Research Council Canada - National Science Library

    Goiato, Marcelo Coelho; Sônego, Mariana Vilela; da Silva, Emily Vivianne Freitas; de Carvalho Dekon, Stefan Fiuza; de Medeiros, Rodrigo Antonio; Carvalho, Karina Helga Turcio de; Dos Santos, Daniela Micheline

    2015-01-01

    ...) for a single tilted implant in the anterior maxillary area. A 57-year-old male patient attended the dentistry college clinic complaining of a vertical fracture of a residual root of the dental element 22...

  7. Environmental oil spill sensitivity atlas for the West Greenland (68 deg.-72 deg. N) coastal zone, 2nd revised edition

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, D.; Johansen, Kasper L.; Mosbech, A.; Boertmann, D.; Wegeberg, S.

    2012-12-15

    This oil spill sensitivity atlas covers the shoreline and the offshore areas of West Greenland between 68 deg. N and 72 deg. N. The coastal zone is divided into 199 shoreline segments and the offshore zone into 8 areas. A sensitivity index value is calculated for each segment/area, and each segment/area is subsequently ranked according to four degrees of sensitivity. Besides this general ranking a number of smaller areas are especially selected as they are of particular significance, they are especially vulnerable to oil spills and they have a size making oil spill response possible. The shoreline sensitivity ranking are shown on 37 maps (in scale 1:250,000), which also show the different elements included and the selected areas. Coast types, logistics and proposed response methods along the coasts are shown on another 37 maps. The sensitivities of the offshore zones are depicted on 4 maps, one for each season. Based on all the information, appropriate oil spill response methods have been assessed for each area. (Author)

  8. On the rms anisotropy at 7 deg and 10 deg observed in the COBE-DMR two year sky maps

    Science.gov (United States)

    Banday, A. J.; Gorski, K. M.; Tenorio, L.; Wright, E. L.; Smoot, G. F.; Lineweaver, C. H.; Kogut, A.; Hinshaw, G.; Bennett, C. L.

    1994-01-01

    The frequency-independent rms temperature fluctuations determined from the Cosmic Background Explorer-Differential Microwave Radiometer (COBE-DMR) two-year sky maps are used to infer the parameter Q(sub rms-PS), which characterizes the normalization of power-law models of primordial cosmological temperature anisotropy, for a forced fit to a scale-invariant Harrison-Zel'dovich (n = 1) spectral model. Using a joint analysis of the 7 deg and 10 deg 'cross'-rms derived from both the 53 and 90 GHz sky maps, we find Q(sub rms-PS) = 17.0(sub -2.1 sup +2.5) micro Kelvin when the low quadrupole is included, and Q(sub rms-PS) = 19.4(sub -2.1 sup +2.3) micro Kelvin excluding the quadrupole. These results are consistent with the n = 1 fits from more sensitive methods. The effect of the low quadrupole derived from the COBE-DMR data on the inferred Q(sub rms-PS) normalization is investigated. A bias to lower Q(sub rms-PS) is found when the quadrupole is included. The higher normalization for a forced n = 1 fit is then favored by the cross-rms technique.

  9. Which way is down? Positional distortion in the tilt illusion.

    Science.gov (United States)

    Tomassini, Alessandro; Solomon, Joshua Adam; Morgan, Michael John

    2014-01-01

    Contextual information can have a huge impact on our sensory experience. The tilt illusion is a classic example of contextual influence exerted by an oriented surround on a target's perceived orientation. Traditionally, the tilt illusion has been described as the outcome of inhibition between cortical neurons with adjacent receptive fields and a similar preference for orientation. An alternative explanation is that tilted contexts could produce a re-calibration of the subjective frame of reference. Although the distinction is subtle, only the latter model makes clear predictions for unoriented stimuli. In the present study, we tested one such prediction by asking four naive subjects to estimate three positions (4, 6, and 8 o'clock) on an imaginary clock face within a tilted surround. To indicate their estimates, they used either an unoriented dot or a line segment, with one endpoint at fixation in the middle of the surround. The surround's tilt was randomly chosen from a set of orientations (± 75°, ± 65°, ± 55°, ± 45°, ± 35°, ± 25°, ± 15°, ± 5° with respect to vertical) across trials. Our results showed systematic biases consistent with the tilt illusion in both conditions. Biases were largest when observers attempted to estimate the 4 and 8 o'clock positions, but there was no significant difference between data gathered with the dot and data gathered with the line segment. A control experiment confirmed that biases were better accounted for by a local coordinate shift than to torsional eye movements induced by the tilted context. This finding supports the idea that tilted contexts distort perceived positions as well as perceived orientations and cannot be readily explained by lateral interactions between orientation selective cells in V1.

  10. Comparing dynamic surface tilt with velocity using an LDV

    Science.gov (United States)

    Bruce, Robert A.

    2004-06-01

    If a laser Doppler vibrometer (LDV) probe beam is normally incident on a resonating metal strip with a mirror-finish, the retro-reflected beam has corresponding dynamic deflections. These lateral beam offsets are proportional to the dynamic surface tilt and can be measured along with the LDV velocity using a separating beam-splitter and a two-dimensional position sensitive detector (PSD). On a thin unbound strip resonating with 'pure mode' deformation, these derivative motions, velocity and tilt, are completely complementary. On a thin unbound plate resonating with 'hybrid mode' deformation, velocity and now two orthogonal tilts are nearly complementary. Maximal tilt has zero velocity, and maximum deformation or velocity has zero tilt. Intermediate values range in complementary fashion except near 'cross-nodes' zones. Here both motion types drop to zero at these cross-node locations. Both velocity and tilt signals are compared simultaneously using a special test fixture. This fixture consists of a stainless steel strip supported on its edges in the center, which can be excited by small speakers at the ends. Two comparison/calibration approaches are demonstrated with a pure 3-0 mode. Significant modal details are also demonstrated by analyzing multiple modes from pulsed excitation, and mapping a 3-1 mode-shape using the combined sensing approaches.

  11. Age, splanchnic vasoconstriction, and heat stress during tilting

    Science.gov (United States)

    Minson, C. T.; Wladkowski, S. L.; Pawelczyk, J. A.; Kenney, W. L.

    1999-01-01

    During upright tilting, blood is translocated to the dependent veins of the legs and compensatory circulatory adjustments are necessary to maintain arterial pressure. For examination of the effect of age on these responses, seven young (23 +/- 1 yr) and seven older (70 +/- 3 yr) men were head-up tilted to 60 degrees in a thermoneutral condition and during passive heating with water-perfused suits. Measurements included heart rate (HR), cardiac output (Qc; acetylene rebreathing technique), central venous pressure (CVP), blood pressures, forearm blood flow (venous occlusion plethysmography), splanchnic and renal blood flows (indocyanine green and p-aminohippurate clearance), and esophageal and mean skin temperatures. In response to tilting in the thermoneutral condition, CVP and stroke volume decreased to a greater extent in the young men, but HR increased more, such that the fall in Qc was similar between the two groups in the upright posture. The rise in splanchnic vascular resistance (SVR) was greater in the older men, but the young men increased forearm vascular resistance (FVR) to a greater extent than the older men. The fall in Qc during combined heat stress and tilting was greater in the young compared with older men. Only four of the young men versus six of the older men were able to finish the second tilt without becoming presyncopal. In summary, the older men relied on a greater increase in SVR to compensate for a reduced ability to constrict the skin and muscle circulations (as determined by changes in FVR) during head-up tilting.

  12. A New Method for Correcting Vehicle License Plate Tilt

    Institute of Scientific and Technical Information of China (English)

    Mei-Sen Pan; Qi Xiong; Jun-Biao Yan

    2009-01-01

    In the course of vehicle license plate (VLP) automatic recognition, tilt correction is a very crucial process. According to Karhunen-Loeve (K-L) transformation, the coordinates of characters in the image are arranged into a two-dimensional covariance matrix, on the basis of which the centered process is carried out. Then, the eigenvector and the rotation angle α are computed in turn. The whole image is rotated by -α. Thus, image horizontal tilt correction is performed. In the vertical tilt correction process, three correction methods, which are K-L transformation method, the line fitting method based on K-means clustering (LFMBKC), and the line fitting based on least squares (LFMBLS), are put forward to compute the vertical tilt angle θ. After shear transformation (ST) is imposed on the rotated image, the final correction image is obtained. The experimental results verify that this proposed method can be easily implemented, and can quickly and accurately get the tilt angle. It provides a new effective way for the VLP image tilt correction as well.

  13. A new tilt on pelvic radiographs: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Richards, P.J. [North Staffordshire Royal Infirmary, Department of Radiology, Stoke-on-Trent, Staffordshire (United Kingdom); Pattison, J.M. [University Hospital of North Staffordshire, Department of Radiology, Stoke on Trent (United Kingdom); Belcher, J. [Keele University, Department of Mathematics, Keele, Staffordshire (United Kingdom); DeCann, R.W. [IMECS, Department of Radiology, Market Drayton, Shropshire (United Kingdom); Anderson, Suzanne [University of Melbourne, Department of Radiology, Melbourne (Australia); Wynn-Jones, C. [University Hospital of North Staffordshire, Department of Orthopaedic Surgery, Stoke on Trent (United Kingdom)

    2009-02-15

    The aim of this study was to evaluate pelvic tilt on commonly performed measurements on radiography in primary protrusio acetabuli and developmental dysplasia of the hip. A dry assembled pelvis and spine skeleton was positioned in an isocentric skull unit and films exposed with increasing degrees of angulation of pelvic tilt. The films were then read by two independent readers for seven different measurements used to evaluate the hips and acetabular: acetabular line to ilioischial line, teardrop appearance, intercristal/intertuberous ratio, co-ordinates of femoral head, centre edge angle, acetabular depth/width ratio and acetabular angle. There was so much variation in the protrusio results that no formal recommendation of any standard radiographic test can be given. Only the inter tuberous distance is not effected by pelvic tilt. The acetabular angles for developmental dysplasia of the hip showed the most potential with pelvic tilt below 15 . As pelvic tilt increases, measurements used in protusio become unreliable, and computed tomography/magnetic resonance imaging are probably going to be more accurate as one can directly visualise pelvic intrusion. We recommend a lateral view to assess the degree of pelvic tilt in patients with protrusion to ensure these measurements are valid. (orig.)

  14. Tilted hexagonal post arrays: DNA electrophoresis in anisotropic media.

    Science.gov (United States)

    Chen, Zhen; Dorfman, Kevin D

    2014-02-01

    Using Brownian dynamics simulations, we show that DNA electrophoresis in a hexagonal array of micron-sized posts changes qualitatively when the applied electric field vector is not coincident with the lattice vectors of the array. DNA electrophoresis in such "tilted" post arrays is superior to the standard "un-tilted" approach; while the time required to achieve a resolution of unity in a tilted post array is similar to an un-tilted array at a low-electric field strengths, this time (i) decreases exponentially with electric field strength in a tilted array and (ii) increases exponentially with electric field strength in an un-tilted array. Although the DNA dynamics in a post array are complicated, the electrophoretic mobility results indicate that the "free path," i.e. the average distance of ballistic trajectories of point-sized particles launched from random positions in the unit cell until they intersect the next post, is a useful proxy for the detailed DNA trajectories. The analysis of the free path reveals a fundamental connection between anisotropy of the medium and DNA transport therein that goes beyond simply improving the separation device.

  15. Dislocation Majorana zero modes in perovskite oxide 2DEG

    Science.gov (United States)

    Chung, Suk Bum; Chan, Cheung; Yao, Hong

    2016-05-01

    Much of the current experimental efforts for detecting Majorana zero modes have been centered on probing the boundary of quantum wires with strong spin-orbit coupling. The same type of Majorana zero mode can also be realized at crystalline dislocations in 2D superconductors with the nontrivial weak topological indices. Unlike at an Abrikosov vortex, at such a dislocation, there is no other low-lying midgap state than the Majorana zero mode so that it avoids usual complications encountered in experimental detections such as scanning tunneling microscope (STM) measurements. We will show that, using the anisotropic dispersion of the t2g orbitals of Ti or Ta atoms, such a weak topological superconductivity can be realized when the surface two-dimensional electronic gas (2DEG) of SrTiO3 or KTaO3 becomes superconducting, which can occur through either intrinsic pairing or proximity to existing s-wave superconductors.

  16. Giant magnetic quadrupole resonance studied with 180 deg. electron scattering

    CERN Document Server

    Neumann-Cosel, P V

    1999-01-01

    The nuclei sup 4 sup 8 Ca and sup 9 sup 0 Zr were investigated in 180 deg. high-resolution inelastic electron scattering for momentum transfers q approx =0.35-0.8 fm sup - sup 1. Complete M2 strength distributions could be extracted in both nuclei up to excitation energies of about 15 MeV utilizing a fluctuation analysis technique. Second-RPA calculations successfully describe the experimentally observed strong fragmentation of the M2 mode. The quenching of the spin part is found to be comparable to the M1 case, contrary to previous claims suggesting a stronger reduction. A quantitative reproduction of the data requires the presence of appreciable orbital strength which can be interpreted as a torsional elastic vibration (the so-called twist mode).

  17. Laicità: finitezza degli ordini e governo delle differenze

    Directory of Open Access Journals (Sweden)

    Nicola Colaianni

    2013-12-01

    Full Text Available Testo della relazione al Convegno Nazionale dell’ADEC sul tema “Per una disciplina che cambia. Il diritto canonico e il diritto ecclesiastico nel tempo presente” (Bologna, 7-9 novembre 2013, destinata alla pubblicazione negli Atti del Convegno. Contributo non sottoposto a valutazioneSOMMARIO: 1. La laicità dei giudici – 2. La laicità dei giuristi – 3. Né regola né valore: un principio – 4. La finitezza degli ordini distinti: dalle materie miste alla sfera dell’indecidibile – 5. L’aconfessionalità sostanziale: a ex parte ecclesiae – 6. (segue: b ex parte status – 7. La laicità come governance delle differenze.

  18. LA FORMAZIONE DEGLI ETNICI NELLA RIFLESSIONE LINGUISTICA DI FRANCESCO CHERUBINI

    Directory of Open Access Journals (Sweden)

    Federica Guerini

    2016-09-01

    Full Text Available Il presente contributo si propone di fornire una descrizione della struttura del Vocabolario Patronimico di Francesco Cherubini e delle fonti empiriche consultate per la sua compilazione. Si accennerà poi a due questioni ricorrenti nel dibattito sulla formazione degli etnici in italiano, ovvero, la presenza di varianti allomorfiche o suppletive, e la motivazione morfo-pragmatica sottesa all’impiego di alcuni suffissi derivativi nella formazione di etnici e aggettivi deonomastici, cercando di chiarire quale attenzione tali tematiche abbiano ricevuto nella riflessione linguistica di Francesco Cherubini. Si formuleranno infine alcune osservazioni conclusive, evidenziando luci ed ombre del Vocabolario Patronimico e sottolineando alcuni degli spunti che tale opera ancora può offrire agli studiosi contemporanei. The formation of ethnic words in Francesco Cherubini’s reflection on language  The aim of this paper is to describe the structure and contents of Francesco Cherubini’s Vocabolario Patronimico, as well as the empirical sources consulted for its compilation. We will address two of the most common issues in the debate on the formation of ethnic nouns and adjectives in Italian, namely the existence of allomorphs and supplementary variants, and the morpho-pragmatic motivation displayed by some of the derivative suffixes occurring in ethnic nouns and adjectives derived from both personal and place names. We will offer a few observations on the place occupied by the above-mentioned issues in Cherubini’s thought and, by analyzing the strengths and weaknesses of the Vocabolario Patronimico, we will draw attention to a few topics which may be of some interest to contemporary scholars.

  19. SPIN TILTS IN THE DOUBLE PULSAR REVEAL SUPERNOVA SPIN ANGULAR-MOMENTUM PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Farr, Will M.; Kremer, Kyle; Kalogera, Vassiliki [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Lyutikov, Maxim, E-mail: w-farr@northwestern.edu, E-mail: kylekremer2012@u.northwestern.edu, E-mail: vicky@northwestern.edu, E-mail: lyutikov@purdue.edu [Physics Department, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States)

    2011-12-01

    The system PSR J0737-3039 is the only binary pulsar known to consist of two radio pulsars (PSR J0737-3039 A and PSR J0737-3039 B). This unique configuration allows measurements of spin orientation for both pulsars: pulsar A's spin is tilted from the orbital angular momentum by no more than 14 deg at 95% confidence; pulsar B's by 130 {+-} 1 deg at 99.7% confidence. This spin-spin misalignment requires that the origin of most of B's present-day spin is connected to the supernova that formed pulsar B. Under the simplified assumption of a single, instantaneous kick during the supernova, the spin could be thought of as originating from the off-center nature of the kick, causing pulsar B to tumble to its misaligned state. With this assumption, and using current constraints on the kick magnitude, we find that pulsar B's instantaneous kick must have been displaced from the center of mass of the exploding star by at least 1 km and probably 5-10 km. Regardless of the details of the kick mechanism and the process that produced pulsar B's current spin, the measured spin-spin misalignment in the double pulsar system provides an empirical, direct constraint on the angular momentum production in this supernova. This constraint can be used to guide core-collapse simulations and the quest for understanding the spins and kicks of compact objects.

  20. Magnetic configurations of the tilted current sheets in magnetotail

    Directory of Open Access Journals (Sweden)

    C. Shen

    2008-11-01

    Full Text Available In this research, the geometrical structures of tilted current sheet and tail flapping waves have been analysed based on multiple spacecraft measurements and some features of the tilted current sheets have been made clear for the first time. The geometrical features of the tilted current sheet revealed in this investigation are as follows: (1 The magnetic field lines (MFLs in the tilted current sheet are generally plane curves and the osculating planes in which the MFLs lie are about vertical to the equatorial plane, while the normal of the tilted current sheet leans severely to the dawn or dusk side. (2 The tilted current sheet may become very thin, the half thickness of its neutral sheet is generally much less than the minimum radius of the curvature of the MFLs. (3 In the neutral sheet, the field-aligned current density becomes very large and has a maximum value at the center of the current sheet. (4 In some cases, the current density is a bifurcated one, and the two humps of the current density often superpose two peaks in the gradient of magnetic strength, indicating that the magnetic gradient drift current is possibly responsible for the formation of the two humps of the current density in some tilted current sheets. Tilted current sheets often appear along with tail current sheet flapping waves. It is found that, in the tail flapping current sheets, the minimum curvature radius of the MFLs in the current sheet is rather large with values around 1 RE, while the neutral sheet may be very thin, with its half thickness being several tenths of RE. During the flapping waves, the current sheet is tilted substantially, and the maximum tilt angle is generally larger than 45°. The phase velocities of these flapping waves are several tens km/s, while their periods and wavelengths are several tens of minutes, and several earth radii, respectively. These tail flapping events generally last several hours and occur

  1. Rules and mechanisms governing octahedral tilts in perovskites under pressure

    Science.gov (United States)

    Xiang, H. J.; Guennou, Mael; Íñiguez, Jorge; Kreisel, Jens; Bellaiche, L.

    2017-08-01

    The rotation of octahedra (octahedral tilting) is common in A B O3 perovskites and relevant to many physical phenomena, ranging from electronic and magnetic properties, metal-insulator transitions to improper ferroelectricity. Hydrostatic pressure is an efficient way to tune and control octahedral tiltings. However, the pressure behavior of such tiltings can dramatically differ from one material to another, with the origins of such differences remaining controversial. In this paper, we discover several new mechanisms and formulate a set of simple rules that allow us to understand how pressure affects oxygen octahedral tiltings via the use and analysis of first-principles results for a variety of compounds. Besides the known A -O interactions, we reveal that the interactions between specific B ions and oxygen ions contribute to the tilting instability. We explain the previously reported trend that the derivative of the oxygen octahedral tilting with respect to pressure (dR /dP ) usually decreases with both the tolerance factor and the ionization state of the A ion by illustrating the key role of A -O interactions and their change under pressure. Furthermore, three new mechanisms/rules are discovered, namely that (i) the octahedral rotations in A B O3 perovskites with empty low-lying d states on the B site are greatly enhanced by pressure, in order to lower the electronic kinetic energy; (ii) dR /dP is enhanced when the system possesses weak tilt instabilities, and (iii) for the most common phase exhibited by perovskites—the orthorhombic Pbnm state—the in-phase and antiphase octahedral rotations are not automatically both suppressed or both enhanced by the application of pressure because of a trilinear coupling between these two rotation types and an antipolar mode involving the A ions. We further predict that the polarization associated with the so-called hybrid improper ferroelectricity could be manipulated by hydrostatic pressure by indirectly controlling the

  2. Recording Tilt with Broadband Seismic Sensors at Erupting Volcanoes

    Science.gov (United States)

    Young, B. E.; Lees, J. M.; Lyons, J. J.

    2011-12-01

    The horizontal components of broadband seismometers are known to be susceptible to gravitational acceleration due to slow tilting, and this has been successfully exploited to assess ground deformation at many volcanoes, including Anatahan (Mariana Islands), Meakan-dake (Japan), Santiaguito (Guatemala) and Stromboli (Italy). Tilt can be estimated from seismic velocity by differentiating, scaling to remove gravity, and applying an instrument correction. The fundamental assumption in estimating tilt from broadband data is that the signal recorded is the result of tilt and not translation, thus analysis of tilt require filtering below corner frequencies of seismic instruments, where the response to tilt should be flat. However, processing techniques for deriving tilt are not uniform among researchers. Filter type and passband allowance for the processing of data sets differs from case to case, and the dominant periods of tilt signals may vary from tens to hundreds of seconds. For instance, data from Santiaguito was filtered in the 600-30s passband, while at Anatahan filters spanned 13 hours to 8 minutes. In our study, we investigate tilt from seismic data sets at Karymsky (Kamchatka, Russia), Fuego (Guatemala), Yasur (Vanuatu), and Tungurahua (Ecuador) to understand implementation and limitations of this tool. We examine the importance of filter-type distortion related to filtering on the seismic signal. For example, a comparison of time domain versus frequency domain implementation is explored using a variety of lowpass and bandpass filters. We also investigate the advantages and drawbacks of causal versus acausal filters. In a few cases tiltmeters have been co-located with broadband seismic sensors for direct comparison. Signals at Mt. St. Helens, Stromboli, Sakurajima, and Semeru show a correlation of tilt and seismic records, although records at Karymsky volcano suggest that no tilt is recorded on either instrument. We speculate that strong vent explosions exhibit

  3. A 360-deg Digital Image Correlation system for materials testing

    Science.gov (United States)

    Genovese, K.; Cortese, L.; Rossi, M.; Amodio, D.

    2016-07-01

    The increasing research interest toward natural and advanced engineered materials demands new experimental protocols capable of retrieving highly dense sets of experimental data on the full-surface of samples under multiple loading conditions. Such information, in fact, would allow to capture the possible heterogeneity and anisotropy of the material by using up-to-date inverse characterization methods. Although the development of object-specific test protocols could represent the optimal choice to address this need, it is unquestionable that universal testing machines (UTM) remain the most widespread and versatile option to test materials and components in both academic and industrial contexts. A major limitation of performing standard material tests with UTM, however, consists in the scarce information obtainable with the commonly associated sensors since they provide only global (LVDTs, extensometers, 2D-video analyzers) or local (strain gages) measures of displacement and strain. This paper presents a 3D Digital Image Correlation (DIC) system developed to perform highly accurate full-surface 360-deg measurements on either standard or custom-shaped samples under complex loading within universal testing machines. To this aim, a low cost and easy to setup video rig was specifically designed to overcome the practical limitations entailed with the integration of a multi-camera system within an already existing loading frame. In particular, the proposed system features a single SLR digital camera moved through multiple positions around the specimen by means of a large rotation stage. A proper calibration and data-processing procedure allows to automatically merge the experimental data obtained from the multiple views with an accuracy of 10-2 m m . The results of a full benchmarking of the metrological performances of the system are here reported and discussed together with illustrative examples of full-360-deg shape and deformation measurements on a Grade X65 steel

  4. Irregularities in Pump-Induced Tilt Above Shallow Aquifers

    Science.gov (United States)

    Kuempel, H. J.; Fabian, M.

    2003-12-01

    Near surface ground tilt induced by the extraction of fluids from subsurface reservoirs has repeatedly been used to constrain reservoir parameters. In general, pump-induced tilt is found to be proportional in strength to the pore pressure gradient created by the pumping, to be a function of poroelastic rock parameters, and to depend on the geometric configuration of the tilt sensor and the productive sections of a well. Assuming radial flow, the strike of the tilt signal should point toward the productive well. However, inversion of near surface tilt can be hampered through irregularities in the pump-induced signal and suffer from insufficient knowledge of the influence of heterogeneities in the subsoil, either within or above the reservoir. We can learn more about the impact of such heterogeneities and reduce ambiguities by analyzing case studies. New observational data from 3 test sites in Germany confirm that a variety of causes can produce irregularities in pump-induced surface deformation, namely: (1) The strike of a tilt signal can considerably deviate from the direction toward the active well. A reason could be that the steepest effective pore pressure gradient builds up in another than radial direction (thereby generating anisotropic fluid flow). Accordingly, tilt hodographs for a complete pump cycle may be elliptic rather than follow a line. (2) The normal rule of how the signal strength depends on the horizontal and the vertical distance may be violated. Structural heterogeneities in the subsurface are the most likely cause for this behaviour. (3) Recovery of the induced tilt signal following the cessation of pumping can be incomplete. This could indicate a non-reversible compaction possibly due to overexploitation of a reservoir. (4) A transient sign reversal of ground tilt may occur during the build-up phase of the signal. This feature could be an analogue to the so-called Noordbergum effect occasionally seen in the response of well levels at locations

  5. Modulated electron bunch with amplitude front tilt in an undulator

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2015-12-15

    In a previous paper we discussed the physics of a microbunched electron beam kicked by the dipole field of a corrector magnet by describing the kinematics of coherent undulator radiation after the kick. We demonstrated that the effect of aberration of light supplies the basis for understanding phenomena like the deflection of coherent undulator radiation by a dipole magnet. We illustrated this fact by examining the operation of an XFEL under the steady state assumption, that is a harmonic time dependence. We argued that in this particular case the microbunch front tilt has no objective meaning; in other words, there is no experiment that can discriminate whether an electron beam is endowed with a microbunch front tilt of not. In this paper we extend our considerations to time-dependent phenomena related with a finite electron bunch duration, or SASE mode of operation. We focus our attention on the spatiotemporal distortions of an X-ray pulse. Spatiotemporal coupling arises naturally in coherent undulator radiation behind the kick, because the deflection process involves the introduction of a tilt of the bunch profile. This tilt of the bunch profile leads to radiation pulse front tilt, which is equivalent to angular dispersion of the output radiation. We remark that our exact results can potentially be useful to developers of new generation XFEL codes for cross-checking their results.

  6. The peculiar velocity field: constraining the tilt of the Universe

    CERN Document Server

    Ma, Yin-Zhe; Feldman, Hume A

    2010-01-01

    A large bulk flow, which is in tension with the Lambda Cold Dark Matter cosmological model, has been observed \\cite{Watkins08,Feldman09}. In this letter, we provide a physical explanation for this very large bulk flow, based on the assumption that the cosmic microwave background (CMB) rest frame does not coincide with the matter rest frame, resulting in a "tilted Universe". We propose a model that takes into account the relative velocity of CMB frame with respect to to the matter rest frame (hereafter tilted velocity), and use Type Ia Supernovae (SN), ENEAR, SFI++, SMAC, and COMPOSITE galaxy catalogues to constrain this tilted velocity. We find that: (1) the magnitude of the tilted velocity $u$ is around 400 km/s, and its direction is close to what is found by \\cite{Watkins08}; for SN, SMAC and COMPOSITE catalogues, $u=0$ is excluded at the two to three sigma level; (2) the constraints on the magnitude of the tilted velocity can result in the constraints on the duration of inflation, due to the fact that infl...

  7. Conservative GRMHD simulations of moderately thin, tilted accretion disks

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Danilo Morales [Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, SP 05508-090 (Brazil); Fragile, P. Chris [Department of Physics and Astronomy, College of Charleston, Charleston, SC 29424 (United States); Zhuravlev, Viacheslav V. [Sternberg Astronomical Institute, Moscow M. V. Lomonosov State University, Universitetskij pr. 13, 119992 Moscow (Russian Federation); Ivanov, Pavel B., E-mail: danilo.morales@iag.usp.br [Astro Space Centre, P. N. Lebedev Physical Institute, 84/32 Profsoyuznaya Street, 117810 Moscow (Russian Federation)

    2014-12-01

    This paper presents our latest numerical simulations of accretion disks that are misaligned with respect to the rotation axis of a Kerr black hole. In this work, we use a new, fully conservative version of the Cosmos++ general relativistic magnetohydrodynamics (GRMHD) code, coupled with an ad hoc cooling function designed to control the thickness of the disk. Together these allow us to simulate the thinnest tilted accretion disks ever using a GRMHD code. In this way, we are able to probe the regime where the dimensionless stress and scale height of the disk become comparable. We present results for both prograde and retrograde cases. The simulated prograde tilted disk shows no sign of Bardeen-Petterson alignment even in the innermost parts of the disk. The simulated retrograde tilted disk, however, does show modest alignment. The implication of these results is that the parameter space associated with Bardeen-Petterson alignment for prograde disks may be rather small, only including very thin disks. Unlike our previous work, we find no evidence for standing shocks in our simulated tilted disks. We ascribe this to the black hole spin, tilt angle, and disk scale height all being small in these simulations. We also add to the growing body of literature pointing out that the turbulence driven by the magnetorotational instability in global simulations of accretion disks is not isotropic. Finally, we provide a comparison between our moderately thin, untilted reference simulation and other numerical simulations of thin disks in the literature.

  8. High tilt susceptibility of the Scintrex CG-5 relative gravimeters

    Science.gov (United States)

    Reudink, R.; Klees, R.; Francis, O.; Kusche, J.; Schlesinger, R.; Shabanloui, A.; Sneeuw, N.; Timmen, L.

    2014-06-01

    We report on the susceptibility of the Scintrex CG-5 relative gravimeters to tilting, that is the tendency of the instrument of providing incorrect readings after being tilted (even by small angles) for a moderate period of time. Tilting of the instrument can occur when in transit between sites usually on the backseat of a car even using the specially designed transport case. Based on a series of experiments with different instruments, we demonstrate that the readings may be offset by tens of Gal. In addition, it may take hours before the first reliable readings can be taken, with the actual time depending on how long the instrument had been tilted. This sensitivity to tilt in combination with the long time required for the instrument to provide reliable readings has not yet been reported in the literature and is not addressed adequately in the Scintrex CG-5 user manual. In particular, the inadequate instrument state cannot easily be detected by checking the readings during the observation or by reviewing the final data before leaving a site, precautions suggested by Scintrex Ltd. In regional surveys with car transportation over periods of tens of minutes to hours, the gravity measurements can be degraded by some 10 Gal. To obtain high-quality results in line with the CG-5 specifications, the gravimeters must remain in upright position to within a few degrees during transits. This requirement may often be unrealistic during field observations, particularly when observing in hilly terrain or when walking with the instrument in a backpack.

  9. Rotating Shaft Tilt Angle Measurement Using an Inclinometer

    Directory of Open Access Journals (Sweden)

    Luo Jun

    2015-10-01

    Full Text Available This paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendicular to the rotating shaft. The reversal measurement method is applied to decrease the effect of inclinometer drifts caused by temperature, to eliminate inclinometer and rotating shaft mechanical error and inclinometer systematic error to attain high measurement accuracy. The uncertainty estimation shows that the accuracy of rotating shaft tilt angle measurement depends mainly on the inclinometer uncertainty and its uncertainty is almost the same as the inclinometer uncertainty in the simulation. The experimental results indicate that measurement time is 4 seconds; the range of rotating shaft tilt angle is 0.002° and its standard deviation is 0.0006° using NS-5/P2 inclinometer, whose precision and resolution are ±0.01° and 0.0005°, respectively.

  10. Rotating Shaft Tilt Angle Measurement Using an Inclinometer

    Science.gov (United States)

    Luo, Jun; Wang, Zhiqian; Shen, Chengwu; Wen, Zhuoman; Liu, Shaojin; Cai, Sheng; Li, Jianrong

    2015-10-01

    This paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendicular to the rotating shaft. The reversal measurement method is applied to decrease the effect of inclinometer drifts caused by temperature, to eliminate inclinometer and rotating shaft mechanical error and inclinometer systematic error to attain high measurement accuracy. The uncertainty estimation shows that the accuracy of rotating shaft tilt angle measurement depends mainly on the inclinometer uncertainty and its uncertainty is almost the same as the inclinometer uncertainty in the simulation. The experimental results indicate that measurement time is 4 seconds; the range of rotating shaft tilt angle is 0.002° and its standard deviation is 0.0006° using NS-5/P2 inclinometer, whose precision and resolution are ±0.01° and 0.0005°, respectively.

  11. Tolerance on tilt error for coherent combining of fiber lasers

    Institute of Scientific and Technical Information of China (English)

    Pu Zhou; Zilun Chen; Xiaolin Wang; Xiao Li; Zejin Liu; Xiaojun Xu

    2009-01-01

    Limited by the precision of optical machining and assembling, the optical axes of lasers in an array cannot be strictly parallel to each other, which will result in the beam quality degradation of the combined beam. The tolerance on tilt error for coherent combining of fiber lasers is studied in detail. The complex amplitude distribution in the far field for the Gaussian beam with tilt angle is obtained by a novel coordinate transform method. Effect of tilt error on coherent combining is modelled analytically. Beam propagation factor is used to evaluate the effect of coherent combining. Numerical results show that for ring-distributed fiber laser array with central wavelength 位 and geometry size D, if the root-mean-square (RMS) value of the tilt error is smaller than 0.72位/D, the energy encircled in the diffraction-limited bucket can be ensured to be more than 50% of the value when there is no tilt error. The results are helpful to the designing and manufacturing of fiber array for coherent combining.

  12. Computational Assessment of the Aerodynamic Performance of a Variable-Speed Power Turbine for Large Civil Tilt-Rotor Application

    Science.gov (United States)

    Welch, Gerard E.

    2011-01-01

    The main rotors of the NASA Large Civil Tilt-Rotor notional vehicle operate over a wide speed-range, from 100% at take-off to 54% at cruise. The variable-speed power turbine offers one approach by which to effect this speed variation. Key aero-challenges include high work factors at cruise and wide (40 to 60 deg.) incidence variations in blade and vane rows over the speed range. The turbine design approach must optimize cruise efficiency and minimize off-design penalties at take-off. The accuracy of the off-design incidence loss model is therefore critical to the turbine design. In this effort, 3-D computational analyses are used to assess the variation of turbine efficiency with speed change. The conceptual design of a 4-stage variable-speed power turbine for the Large Civil Tilt-Rotor application is first established at the meanline level. The design of 2-D airfoil sections and resulting 3-D blade and vane rows is documented. Three-dimensional Reynolds Averaged Navier-Stokes computations are used to assess the design and off-design performance of an embedded 1.5-stage portion-Rotor 1, Stator 2, and Rotor 2-of the turbine. The 3-D computational results yield the same efficiency versus speed trends predicted by meanline analyses, supporting the design choice to execute the turbine design at the cruise operating speed.

  13. Effect of hydration on plasma vasopressin, renin, and aldosterone responses to head-up tilt

    Science.gov (United States)

    Harrison, M. H.; Geelen, G.; Keil, L. C.; Wade, C. A.; Hill, L. C.

    1986-01-01

    If plasma vasopressin (PVP), plasma renin (PRA), and plasma aldosterone (PA) responses to change in posture are mediated only by alterations in intrathoracic baroreceptor activity hydration status should have minimal influence on these responses. To test this hypothesis, six male subjects underwent 45 min of 70 deg head-up tilt (HUT) following 26 h dehydration, and again, 105 min later, following rehydration. Compared with preceding supine hydrated control values, PVP, PRA, and PA increased (p less than 0.001) during dehydrated HUT, but only PVP and PRA increased during rehydrated HUT (p less than 0.001). The dissociation during rehydrated HUT of PRA and PA may have been related more to the reduction (p less than 0.001) in plasma potassium concentration than to the accompanying decrease (p less than 0.001) in plasma osmolality and sodium concentration. Although increases in PVP and PRA during HUT were attenuated (p less than 0.01) following rehydration, this attenuation was associated with the absence of symptoms of overt hypotension following rehydration. However, since rehydration did not abolish the increases in PVP and PRA induced by HUT, it is concluded that the present observations support the concept of intrathoracic baroreceptor involvement in the regulation of vasopressin secretion and renin release.

  14. COSMOS Photometric Redshifts with 30-bands for 2-deg2

    CERN Document Server

    Ilbert, O; Salvato, M; Aussel, H; McCracken, H J; Sanders, D B; Scoville, N; Kartaltepe, J; Arnouts, S; Le Floc'h, E; Mobasher, B; Taniguchi, Y; Lamareille, F; Leauthaud, A; Sasaki, S; Thompson, D; Zamojski, M; Zamorani, G; Bardelli, S; Bolzonella, M; Bongiorno, A; Brusa, M; Caputi, K I; Carollo, C M; Contini, T; Cook, R; Coppa, G; Cucciati, O; De la Torre, S; de Ravel, L; Franzetti, P; Garilli, B; Hasinger, G; Iovino, A; Kampczyk, P; Kneib, J -P; Knobel, C; Kovac, K; Le Borgne, J F; Le Brun, V; Le Fèvre, O; Lilly, S; Looper, D; Maier, C; Mainieri, V; Mellier, Y; Mignoli, M; Murayama, T; Pellò, R; Peng, Y; Pérez-Montero, E; Renzini, A; Ricciardelli, E; Schiminovich, D; Scodeggio, M; Shioya, Y; Silverman, Joseph; Surace, J; Tanaka, M; Tasca, L; Tresse, L; Vergani, D; Zucca, E

    2008-01-01

    We present accurate photometric redshifts in the 2-deg2 COSMOS field. The redshifts are computed with 30 broad, intermediate, and narrow bands covering the UV (GALEX), Visible-NIR (Subaru, CFHT, UKIRT and NOAO) and mid-IR (Spitzer/IRAC). A chi2 template-fitting method (Le Phare) was used and calibrated with large spectroscopic samples from VLT-VIMOS and Keck-DEIMOS. We develop and implement a new method which accounts for the contributions from emission lines (OII, Hbeta, Halpha and Ly) to the spectral energy distributions (SEDs). The treatment of emission lines improves the photo-z accuracy by a factor of 2.5. Comparison of the derived photo-z with 4148 spectroscopic redshifts (i.e. Delta z = zs - zp) indicates a dispersion of sigma_{Delta z/(1+zs)}=0.007 at i<22.5, a factor of 2-6 times more accurate than earlier photo-z in the COSMOS, CFHTLS and COMBO-17 survey fields. At fainter magnitudes i<24 and z<1.25, the accuracy is sigma_{Delta z/(1+zs)}=0.012. The deep NIR and IRAC coverage enables the ph...

  15. LE ZANZARE ITALIANE: GENERALITÀ E IDENTIFICAZIONE DEGLI ADULTI (DIPTERA, CULICIDAE

    Directory of Open Access Journals (Sweden)

    Francesco Severini

    2009-12-01

    Full Text Available Nel presente lavoro vengono riportate le informazioni essenziali su tassonomia e biologia nonché sugli aspetti ecologici degli adulti dei Culicidi italiani. Attualmente la fauna culicidica italiana comprende 64 specie appartenenti a 2 sottofamiglie e 8 generi. Alla sottofamiglia Anophelinae appartiene soltanto il genere Anopheles, presente con 16 specie raggruppate in due sottogeneri. Alla sottofamiglia Culicinae appartengono i rimanenti 7 generi: Aedes con 6 specie raggruppate in 3 sottogeneri, Coquillettidia con 2 specie, Ochlerotatus con 20 specie raggruppate in 3 sottogeneri, Culex con 12 specie raggruppate in 4 sottogeneri, Culiseta con 6 specie raggruppate in 3 sottogeneri, Orthopodomyia e Uranotaenia con una specie ognuna. In questo contesto vengono fornite le chiavi di identificazione specifica per le zanzare adulte, in italiano e in inglese. Le chiavi sono corredate da un’ampia iconografia (figure 1-75. Alle chiavi fa seguito la diagnosi morfologica dell’adulto di ogni specie con note sulla relativa biologia e distribuzione. Per ulteriori approfondimenti viene riportata la bibliografia completa sulle zanzare della fauna italiana dal 1960 ed i precedenti lavori più autorevoli.

  16. Come e cosa desidera la narrativa italiana degli anni Zero

    Directory of Open Access Journals (Sweden)

    Gianluigi Simonetti

    2013-05-01

    Full Text Available L'articolo analizza il trattamento del tema del desiderio - erotico e amoroso - nel romanzo italiano degli ultimi anni, impegnandosi nell'esame ravvicinato di alcuni testi esemplari. La campionatura vuole da un lato isolare alcune opere rappresentative della situazione attuale della narrativa contemporanea, dall'altro  proporre un'ipotesi categoriale che seziona il campo di studio in tre parti; il sondaggio sembra infatti suggerire che le dinamiche del desiderio vengono rese in maniera specifica nei diversi ambiti della letteratura di consumo, in quella di 'nobile intrattenimento' e in quella 'forte' e letterariamente più ambiziosa. L'analisi formale risulta insomma integrata a una prospettiva di stroria dello stile, secondo un metodo che permette di utilizzare la figuralità letteraria come 'indicatore sociologico' di processi politici (e forse antropologici in atto.

  17. Le caratteristiche degli acquirenti e venditori di abitazioni

    Directory of Open Access Journals (Sweden)

    Erika Ghiraldo

    2011-12-01

    Full Text Available L’incrocio dei dati contenuti nelle dichiarazioni dei redditi con quelli contenuti negli archivi della Pubblicità Immobiliare (ex Conservatorie rende disponibili molte informazioni sulle caratteristiche dei contraenti che hanno effettuato una compravendita di unità immobiliari. Considerando principalmente le compravendite di unità immobiliari del settore residenziale effettuate da persone fisiche sono trattate informazioni sul reddito dichiarato al fisco, l’età e l’attività di lavoro prevalente. È fornito un quadro sintetico della distribuzione delle compravendite, in termini di Numero di Transazioni Normalizzate (NTN e per dimensione delle abitazioni, per ciascuna caratteristica sia per gli acquirenti che per i venditori. La disponibilità dell’informazione sulla residenza dei soggetti consente, inoltre, di condurre un’analisi sulla provenienza degli acquirenti rispetto al luogo di ubicazione dell’immobile compravenduto. E’ possibile così analizzare la composizione del mercato distinguendo la quota di acquisti imputabile a soggetti residenti nello stesso Comune di ubicazione dell’immobile (mercato comunale dalla quota alimentata da soggetti residenti in altro Comune di una stessa provincia (mercato infraprovinciale o di altra provincia (mercato extra-provinciale. Quest’ultima indagine risulta molto interessante se effettuata su singole città. Sono, quindi, riportati i risultati dell’analisi per i mercati delle città di Milano, Roma e Napoli.

  18. Influence of passive leg movements on blood circulation on the tilt table in healthy adults

    Directory of Open Access Journals (Sweden)

    Czell David

    2004-10-01

    Full Text Available Abstract Background One problem in the mobilization of patients with neurological diseases, such as spinal cord injury, is the circulatory collapse that occurs while changing from supine to vertical position because of the missing venous pump due to paralyzed leg muscles. Therefore, a tilt table with integrated stepping device (tilt stepper was developed, which allows passive stepping movements for performing locomotion training in an early state of rehabilitation. The aim of this pilot study was to investigate if passive stepping and cycling movements of the legs during tilt table training could stabilize blood circulation and prevent neurally-mediated syncope in healthy young adults. Methods In the first experiment, healthy subjects were tested on a traditional tilt table. Subjects who had a syncope or near-syncope in this condition underwent a second trial on the tilt stepper. In the second experiment, a group of healthy subjects was investigated on a traditional tilt table, the second group on the tilt ergometer, a device that allows cycling movements during tilt table training. We used the chi-square test to compare the occurrence of near-syncope/syncope in both groups (tilt table/tilt stepper and tilt table/tilt ergometer and ANOVA to compare the blood pressure and heart rate between the groups at the four time intervals (supine, at 2 minutes, at 6 minutes and end of head-up tilt. Results Separate chi-square tests performed for each experiment showed significant differences in the occurrence of near syncope or syncope based on the device used. Comparison of the two groups (tilt stepper/ tilt table in experiment one (ANOVA showed that blood pressure was significantly higher at the end of head-up tilt on the tilt stepper and on the tilt table there was a greater increase in heart rate (2 minutes after head-up tilt. Comparison of the two groups (tilt ergometer/tilt table in experiment 2 (ANOVA showed that blood pressure was significantly

  19. Laser Guide Star Adaptive Optics without Tip-tilt

    CERN Document Server

    Davies, R; Lidman, C; Louarn, M Le; Kasper, M; Förster-Schreiber, N M; Roccatagliata, V; Ageorges, N; Amico, P; Dumas, C; Mannucci, F

    2008-01-01

    Adaptive optics (AO) systems allow a telescope to reach its diffraction limit at near infrared wavelengths. But to achieve this, a bright natural guide star (NGS) is needed for the wavefront sensing, severely limiting the fraction of the sky over which AO can be used. To some extent this can be overcome with a laser guide star (LGS). While the laser can be pointed anywhere in the sky, one still needs to have a natural star, albeit fainter, reasonably close to correct the image motion (tip-tilt) to which laser guide stars are insensitive. There are in fact many astronomical targets without suitable tip-tilt stars, but for which the enhanced resolution obtained with the Laser Guide Star Facility (LGSF) would still be very beneficial. This article explores what adaptive optics performance one might expect if one dispenses with the tip-tilt star, and in what situations this mode of observing might be needed.

  20. Quantum well electronic states in a tilted magnetic field

    Science.gov (United States)

    Trallero-Giner, C.; Padilha, J. X.; Lopez-Richard, V.; Marques, G. E.; Castelano, L. K.

    2017-08-01

    We report the energy spectrum and the eigenstates of conduction and uncoupled valence bands of a quantum well under the influence of a tilted magnetic field. In the framework of the envelope approximation, we implement two analytical approaches to obtain the nontrivial solutions of the tilted magnetic field: (a) the Bubnov-Galerkin spectral method and b) the perturbation theory. We discuss the validity of each method for a broad range of magnetic field intensity and orientation as well as quantum well thickness. By estimating the accuracy of the perturbation method, we provide explicit analytical solutions for quantum wells in a tilted magnetic field configuration that can be employed to study several quantitative phenomena.

  1. Flow tilt angles near forest edges - Part 1: Sonic anemometry

    DEFF Research Database (Denmark)

    Dellwik, Ebba; Mann, Jakob; Larsen, Klaus Steenberg

    2010-01-01

    -sets. These features of the investigated sonic anemometers make them unsuitable for measuring vertical velocities over highly turbulent forested terrain. By comparing the sonic anemometer results to that of a conically scanning Doppler lidar (Dellwik et al., 2010b), sonic anemometer accuracy for measuring mean flow...... distortion and vertical alignment, it was only possible to a limited extent to relate sonic anemometer flow tilt angles to upwind forest edges, but the results by the lidar indicated that an internal boundary layer affect flow tilt angles at 21m above the forest. This is in accordance with earlier studies......An analysis of flow tilt angles from a fetch-limited beech forest site with clearings is presented in the context of vertical advection of carbon dioxide. Flow angles and vertical velocities from two sonic anemometers by different manufacturers were analyzed. Instead of using rotations, where zero...

  2. Interacting tilt and kink instabilities in repelling current channels

    CERN Document Server

    Keppens, Rony; Xia, Chun

    2014-01-01

    We present a numerical study in resistive magnetohydrodynamics where the initial equilibrium configuration contains adjacent, oppositely directed, parallel current channels. Since oppositely directed current channels repel, the equilibrium is liable to an ideal magnetohydrodynamic tilt instability. This tilt evolution, previously studied in planar settings, involves two magnetic islands or fluxropes, which on Alfvenic timescales undergo a combined rotation and separation. This in turn leads to the creation of (near) singular current layers, posing severe challenges to numerical approaches. Using our open-source grid-adaptive MPI-AMRVAC software, we revisit the planar evolution case in compressible MHD, as well as its extension to 2.5D and full 3D scenarios. As long as the third dimension remains ignorable, pure tilt evolutions result which are hardly affected by out of plane magnetic field components. In all 2.5D runs, our simulations do show secondary tearing type disruptions throughout the near singular cur...

  3. STUDY ON DYNAMIC CURVING BEHAVIOR OF TILTING PASSENGER CARS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By using tilting carbodies, train can negotiate at a higher speed without reducing the passenger's ride quality.This is a good method to allow a significant increase in speed at existing track to improve the railway transportation capa-bility, and to enhance the competition ability of railways with other transportation systems. With the increase of the curvenegotiation speed, the wheel-rail lateral forces and wheel-rail wear of the tilting train will increase. The self-steering radialbogie is an effective way to solve the problem. The dynamic model of the tilting passenger car with self-steering bogies isestablished in detail, and the curving performance of the car is investigated.

  4. Coulomb interaction effect in tilted Weyl fermion in two dimensions

    Science.gov (United States)

    Isobe, Hiroki; Nagaosa, Naoto

    Weyl fermions with tilted linear dispersions characterized by several different velocities appear in some systems including the quasi-two-dimensional organic semiconductor α-(BEDT-TTF)2I3 and three-dimensional WTe2. The Coulomb interaction between electrons modifies the velocities in an essential way in the low energy limit, where the logarithmic corrections dominate. Taking into account the coupling to both the transverse and longitudinal electromagnetic fields, we derive the renormalization group equations for the velocities of the tilted Weyl fermions in two dimensions, and found that they increase as the energy decreases and eventually hit the velocity of light c to result in the Cherenkov radiation. Especially, the system restores the isotropic Weyl cone even when the bare Weyl cone is strongly tilted and the velocity of electrons becomes negative in certain directions.

  5. The semiology of tilt-induced psychogenic pseudosyncope.

    Science.gov (United States)

    Tannemaat, Martijn R; van Niekerk, Julius; Reijntjes, Robert H; Thijs, Roland D; Sutton, Richard; van Dijk, J Gert

    2013-08-20

    To provide a detailed semiology to aid the clinical recognition of psychogenic pseudosyncope (PPS), which concerns episodes of apparent transient loss of consciousness (TLOC) that mimic syncope. We analyzed all consecutive tilt-table tests from 2006 to 2012 showing proven PPS, i.e., apparent TLOC had occurred without EEG changes or a decrease in heart rate (HR) or blood pressure (BP). We analyzed baseline characteristics, video data, EEG, ECG, and continuous BP measurements on a 1-second time scale. Data were compared with those of 69 cases of tilt-induced vasovagal syncope (VVS). Of 800 tilt-table tests, 43 (5.4%) resulted in PPS. The majority (74%) were women. The median duration of apparent TLOC was longer in PPS (44 seconds) than in VVS (20 seconds, p semiology of PPS as a clinical entity is vital to ensure accurate diagnosis.

  6. Robust tilt and lock mechanism for hopping actuator

    Energy Technology Data Exchange (ETDEWEB)

    Salton, Jonathan R.; Buerger, Stephen; Dullea, Kevin J.; Marron, Lisa C.; Salisbury, Curt Michael; Spletzer, Barry Louis

    2017-02-07

    A tilt and lock apparatus that includes a tilt servomechanism, a spiral torsion spring, a lock wheel, and a lock hook is described herein. The spiral torsion spring is mechanically coupled to the tilt servomechanism and the lock wheel (which includes an opening). When a shaft is positioned through the opening, rotation of the lock wheel is in unison with rotation of the shaft. An external surface of the lock wheel includes one or more grooves. The lock hook includes a head that engages and disengages the grooves. The lock wheel is stationary when the head engages one of the grooves and is rotatable when the head disengages the grooves. The head and the grooves are geometrically aligned when engaged to prevent creation of a force that acts to disengage the head responsive to an applied force acting on the shaft.

  7. Full vector complex coupled mode theory for tilted fiber gratings.

    Science.gov (United States)

    Lu, Yu-Chun; Huang, Wei-Ping; Jian, Shui-Sheng

    2010-01-18

    A full vector complex coupled mode theory (CMT) for the analysis of tilted fiber gratings is presented. With the combination of the perfectly matched layer (PML) and the perfectly reflecting boundary (PRB), the continuous radiation modes are well represented by a set of discrete complex modes. Simulation of coupling to radiation modes is greatly simplified and may be treated in the same fashion as guided modes. Numerical results of the tilted fiber Bragg gratings (TFBGs) with outer-cladding index equal, lower and higher than that of the inner-cladding indicate that the complex coupled mode approach is highly effective in the simulation of couplings to cladding and radiation modes in tilted fiber gratings. The reflective TFBGs are investigated by the proposed approach in detail.

  8. Ground tilt monitoring at Phlegraean Fields (Italy: a methodological approach

    Directory of Open Access Journals (Sweden)

    C. Del Gaudio

    2003-06-01

    Full Text Available Among geodetic methods used for monitoring ground deformation in volcanic areas, tiltmetry represents the most rapid technique and therefore it is used by almost all the volcanological observatories in the world. The deformation of volcanic building is not only the result of endogenous causes (i.e. dykes injection or magma rising, but also non-tectonic environmental factors. Such troubles cannot be removed completely but they can be reduce. This article outlines the main source of errors affecting the signals recorded by Phlegraean tilt, network, such as the dependence of the tilt response on temperature and to the thermoelastic effect on ground deformation. The analytical procedure used to evaluate about such errors and their reduction is explained. An application to data acquired from the tilt network during two distinct phases of ground uplift and subsidence of the Phlegraean Fields is reported.

  9. Tilted dipole model for bias-dependent photoluminescence pattern

    Energy Technology Data Exchange (ETDEWEB)

    Fujieda, Ichiro, E-mail: fujieda@se.ritsumei.ac.jp; Suzuki, Daisuke; Masuda, Taishi [Department of Electrical and Electronic Engineering, Ritsumeikan University, Kusatsu 525-8577 (Japan)

    2014-12-14

    In a guest-host system containing elongated dyes and a nematic liquid crystal, both molecules are aligned to each other. An external bias tilts these molecules and the radiation pattern of the system is altered. A model is proposed to describe this bias-dependent photoluminescence patterns. It divides the liquid crystal/dye layer into sub-layers that contain electric dipoles with specific tilt angles. Each sub-layer emits linearly polarized light. Its radiation pattern is toroidal and is determined by the tilt angle. Its intensity is assumed to be proportional to the power of excitation light absorbed by the sub-layer. This is calculated by the Lambert-Beer's Law. The absorption coefficient is assumed to be proportional to the cross-section of the tilted dipole moment, in analogy to the ellipsoid of refractive index, to evaluate the cross-section for each polarized component of the excitation light. Contributions from all the sub-layers are added to give a final expression for the radiation pattern. Self-absorption is neglected. The model is simplified by reducing the number of sub-layers. Analytical expressions are derived for a simple case that consists of a single layer with tilted dipoles sandwiched by two layers with horizontally-aligned dipoles. All the parameters except for the tilt angle can be determined by measuring transmittance of the excitation light. The model roughly reproduces the bias-dependent photoluminescence patterns of a cell containing 0.5 wt. % coumarin 6. It breaks down at large emission angles. Measured spectral changes suggest that the discrepancy is due to self-absorption and re-emission.

  10. Interacting tilt and kink instabilities in repelling current channels

    Energy Technology Data Exchange (ETDEWEB)

    Keppens, R.; Porth, O.; Xia, C., E-mail: rony.keppens@wis.kuleuven.be [Centre for mathematical Plasma-Astrophysics, Department of Mathematics, KU Leuven, B-3001 Leuven (Belgium)

    2014-11-01

    We present a numerical study in resistive magnetohydrodynamics (MHD) where the initial equilibrium configuration contains adjacent, oppositely directed, parallel current channels. Since oppositely directed current channels repel, the equilibrium is liable to an ideal magnetohydrodynamic tilt instability. This tilt evolution, previously studied in planar settings, involves two magnetic islands or flux ropes, which on Alfvénic timescales undergo a combined rotation and separation. This in turn leads to the creation of (near) singular current layers, posing severe challenges to numerical approaches. Using our open-source grid-adaptive MPI-AMRVAC software, we revisit the planar evolution case in compressible MHD, as well as its extension to two-and-a-half-dimensional (2.5D) and full three-dimensional (3D) scenarios. As long as the third dimension can be ignored, pure tilt evolutions result that are hardly affected by out of plane magnetic field components. In all 2.5D runs, our simulations do show secondary tearing type disruptions throughout the near singular current sheets in the far nonlinear saturation regime. In full 3D runs, both current channels can be liable to additional ideal kink deformations. We discuss the effects of having both tilt and kink instabilities acting simultaneously in the violent, reconnection-dominated evolution. In 3D, both the tilt and the kink instabilities can be stabilized by tension forces. As a concrete space plasma application, we argue that interacting tilt-kink instabilities in repelling current channels provide a novel route to initiate solar coronal mass ejections, distinctly different from the currently favored pure kink or torus instability routes.

  11. Gating-by-Tilt of Mechanically Sensitive Membrane Channels

    Science.gov (United States)

    Turner, Matthew S.; Sens, Pierre

    2004-09-01

    We propose an alternative mechanism for the gating of biological membrane channels in response to membrane tension that involves a change in the slope of the membrane near the channel. Under biological membrane tensions we show that the energy difference between the closed (tilted) and open (untilted) states can far exceed kBT and is comparable to what is available under simple dilational gating. Recent experiments demonstrate that membrane leaflet asymmetries (spontaneous curvature) can strongly affect the gating of some channels. Such a phenomenon would be easier to explain under gating-by-tilt, given its novel intrinsic sensitivity to such asymmetry.

  12. The BLAST View of the Star Forming Region in Aquila (ell=45deg,b=0deg)

    CERN Document Server

    Rivera-Ingraham, Alana; Bock, James J; Chapin, Edward L; Devlin, Mark J; Dicker, Simon R; Griffin, Matthew; Gundersen, Joshua O; Halpern, Mark; Hargrave, Peter C; Hughes, David H; Klein, Jeff; Marsden, Gaelen; Martin, Peter G; Mauskopf, Philip; Netterfield, Calvin B; Olmi, Luca; Patanchon, Guillaume; Rex, Marie; Scott, Douglas; Semisch, Christopher; Truch, Matthew D P; Tucker, Carole; Tucker, Gregory S; Viero, Marco P; Wiebe, Donald V

    2010-01-01

    We have carried out the first general submillimeter analysis of the field towards GRSMC 45.46+0.05, a massive star forming region in Aquila. The deconvolved 6 deg^2 (3\\degree X 2\\degree) maps provided by BLAST in 2005 at 250, 350, and 500 micron were used to perform a preliminary characterization of the clump population previously investigated in the infrared, radio, and molecular maps. Interferometric CORNISH data at 4.8 GHz have also been used to characterize the Ultracompact HII regions (UCHIIRs) within the main clumps. By means of the BLAST maps we have produced an initial census of the submillimeter structures that will be observed by Herschel, several of which are known Infrared Dark Clouds (IRDCs). Our spectral energy distributions of the main clumps in the field, located at ~7 kpc, reveal an active population with temperatures of T~35-40 K and masses of ~10^3 Msun for a dust emissivity index beta=1.5. The clump evolutionary stages range from evolved sources, with extended HII regions and prominent IR ...

  13. High-spin structure of sup 1 sup 8 sup 2 sup , sup 1 sup 8 sup 4 Os in tilted axis cranking approach

    CERN Document Server

    Ansari, A; Onishi, N; Horibata, T

    1999-01-01

    A detailed investigation of the high-spin structures of sup 1 sup 8 sup 2 sup , sup 1 sup 8 sup 4 Os has been carried out following a self-consistent two-dimensional (in the x-z plane) tilted axis cranked HFB approach employing a pairing-plus-quadrupole model interaction Hamiltonian. The tilt angle psi is measured with respect to the x-axis so that psi=90 deg. represents the nuclear symmetry z-axis. We have investigated the variation of the shape parameters for a given value of spin, J (up to J=40) as a function of psi. With the force parameters considered here, we do not find for any J the lowest energy solution corresponding to a tilted axis rotation. However, for spins in the region of the backbend (J approx 16) and beyond, the shape parameters change in a complex manner exhibiting local minima as a function of psi. This implies the importance of the dynamical effects due to the wobbling motion of the rotation axis which warrants treatment through a dynamical theory like the generator coordinate method (GC...

  14. The dynamic performance of narrow actively tilting vehicles

    NARCIS (Netherlands)

    Pauwelussen, J.P.

    2000-01-01

    The major advantage of a motorcycle with respect to a passenger car is the possibility of the driver to tilt during cornering and thereby maintaining stability whereas a passenger car will suffer from the risk of capsizing at high speed. This observation has motivated recently various manufacturers

  15. Dynamic characteristics of polymer faced tilting pad journal bearings

    DEFF Research Database (Denmark)

    Simmons, Gregory F.; Cerda Varela, Alejandro Javier; Santos, Ilmar

    2014-01-01

    Dynamic characteristics of polymer faced tilting pad journal bearings are presented. Investigations are conducted using a single pad, load on pad configuration over a range of shaft speeds and loads. Two polyether ether ketone (PEEK) faced pads, one polytetrafluoroethylene (PTFE) faced pad and tw...

  16. Modelling of LEG tilting pad journal bearings with active lubrication

    DEFF Research Database (Denmark)

    Cerda Varela, Alejandro Javier; García, Asier Bengoechea; Santos, Ilmar

    2017-01-01

    This work constitutes the first step in a research effort aimed at studying the feasibility of introducing an active lubrication concept in tilting pad journal bearings (TPJBs) that feature the leading edge groove (LEG) lubrication system. The modification of the oil flow into each pad supply gro...

  17. Compression paddle tilt correction in full-field digital mammograms.

    NARCIS (Netherlands)

    Kallenberg, M.G.J.; Karssemeijer, N.

    2012-01-01

    During the acquisition of a mammogram the breast is compressed between the compression paddle and the support table. When compression is applied, the upper plate is tilted which results in variation in breast thickness from the chest wall to the breast margin. Variation in breast thickness influence

  18. The dynamic performance of narrow actively tilting vehicles

    NARCIS (Netherlands)

    Pauwelussen, J.P.

    2000-01-01

    The major advantage of a motorcycle with respect to a passenger car is the possibility of the driver to tilt during cornering and thereby maintaining stability whereas a passenger car will suffer from the risk of capsizing at high speed. This observation has motivated recently various manufacturers

  19. Modeling quantitative phase image formation under tilted illuminations.

    Science.gov (United States)

    Bon, Pierre; Wattellier, Benoit; Monneret, Serge

    2012-05-15

    A generalized product-of-convolution model for simulation of quantitative phase microscopy of thick heterogeneous specimen under tilted plane-wave illumination is presented. Actual simulations are checked against a much more time-consuming commercial finite-difference time-domain method. Then modeled data are compared with experimental measurements that were made with a quadriwave lateral shearing interferometer.

  20. Elastohydrodynamics Applied to Active Tilting-Pad Journal Bearings

    DEFF Research Database (Denmark)

    Haugaard, Martin Asger; Santos, Ilmar

    2010-01-01

    The static and dynamic properties of tilting-pad journal bearings with controllable radial oil injection are investigated theoretically. The tilting pads are modeled as flexible structures and their behavior is described using a three-dimensional finite element framework and linear elasticity. Th...... is dynamically perturbed and subsequently condensed to a 2 X 2 system, keeping only the lateral motion of the rotor. As expected, bearing dynamic coefficients are heavily influenced by the control parameters and pad compliance.......The static and dynamic properties of tilting-pad journal bearings with controllable radial oil injection are investigated theoretically. The tilting pads are modeled as flexible structures and their behavior is described using a three-dimensional finite element framework and linear elasticity....... The oil film pressure and flow are considered to follow the modified Reynolds equation, which includes the contribution from controllable radial oil injection. The Reynolds equation is solved using a two-dimensional finite element mesh. The rotor is considered to be rigid in terms of shape and size...

  1. Tilted axis rotation in odd-odd {sup 164}Tm

    Energy Technology Data Exchange (ETDEWEB)

    Reviol, W.; Riedinger, L.L.; Wang, X.Z.; Zhang, J.Y. [Univ. of Tennessee, Knoxville, TN (United States)] [and others

    1996-12-31

    Ten band structures are observed in {sup 164}Tm, among them sets of parallel and anti-parallel couplings of the proton and neutron spins. The Tilted Axis Cranking scheme is applied for the first time to an odd-odd nucleus in a prominent region of nuclear deformation.

  2. Discontinuity effects in dynamically loaded tilting pad journal bearings

    DEFF Research Database (Denmark)

    Thomsen, Kim; Klit, Peder; Vølund, Anders

    2011-01-01

    This paper describes two discontinuity effects that can occur when modelling radial tilting pad bearings subjected to high dynamic loads. The first effect to be treated is a pressure build-up discontinuity effect. The second effect is a contact-related discontinuity that disappears when a contact...

  3. Cellular structures using U_q-tilting modules

    DEFF Research Database (Denmark)

    Andersen, Henning Haahr; Stroppel, Catharina; Tubbenhauer, Daniel

    We use the theory of Uq-tilting modules to construct cellular bases for centralizer algebras. Our methods are quite general and work for any quantum group Uq attached to a Cartan matrix and include the non semi-simple cases for q being a root of unity and ground fields of positive characteristic...

  4. The impact of gravity during head-up tilt

    DEFF Research Database (Denmark)

    Olufsen, Mette; Smith, Brittany; Mehlsen, Jesper

    2011-01-01

    The impact of gravity during head-up tilt, a test often used in the clinic to diagnose patients who suffer from dizziness or frequent episodes of syncope, is not well described. This study uses mathematical modeling to analyze experimental blood pressure data measured at the level of the aorta...

  5. Performance of a Tilt Current Meter in the Surf Zone

    DEFF Research Database (Denmark)

    Hansen, Asger Bendix; Carstensen, Stefan; Christensen, Drude Fritzbøger

    2017-01-01

    Tilt Current Meters (TCM’s) are relatively simple and inexpensive instruments for measuring currents in rivers and inthe sea. Their low cost and easy deployment means that a relatively large number of TCM’s can be deployed comparedto more conventional current meters such as Acoustic Doppler...

  6. Cholesterol orientation and tilt modulus in DMPC bilayers

    OpenAIRE

    Khelashvili, George; Pabst, Georg; Harries, Daniel

    2010-01-01

    We performed molecular dynamics (MD) simulations of hydrated bilayers containing mixtures of dimyristoylphosphatidylcholine (DMPC) and Cholesterol at various ratios, to study the effect of cholesterol concentration on its orientation, and to characterize the link between cholesterol tilt and overall phospholipid membrane organization. The simulations show a substantial probability for cholesterol molecules to transiently orient perpendicular to the bilayer normal, and suggest that cholesterol...

  7. Optical system design with conformal decentered and tilted elements

    Institute of Scientific and Technical Information of China (English)

    Jun Chang; Wubin He; Ruirui Wang; Shulong Feng

    2011-01-01

    @@ We investigate the aberration properties of the conformal optical system with decentered and tilted elements by vector aberration theory.By decentering and tilting the window and corrector of the system,two elements are effectively used together in a particular manner by aberration compensation to achieve off-axis imaging.A conceptual design is performed with a half-field of 2°, the F# of 4, and the wavelength ranging of 3700-4800 nm.The imaging quality can reach the optical diffraction limit and satisfy corresponding requirements.%We investigate the aberration properties of the conformal optical system with decentered and tilted elements by vector aberration theory.By decentering and tilting the window and corrector of the system,two elements are effectively used together in a particular manner by aberration compensation to achieve off-axis imaging.A conceptual design is performed with a half-field of 2°, the F# of 4, and the wavelength ranging of 3700-4800 nm.The imaging quality can reach the optical diffraction limit and satisfy corresponding requirements.

  8. Tilted Thick-Disk Accretion onto a Kerr Black Hole

    Energy Technology Data Exchange (ETDEWEB)

    Fragile, P C; Anninos, P

    2003-12-12

    We present the first results from fully general relativistic numerical studies of thick-disk accretion onto a rapidly-rotating (Kerr) black hole with a spin axis that is tilted (not aligned) with the angular momentum vector of the disk. We initialize the problem with the solution for an aligned, constant angular momentum, accreting thick disk around a black hole with spin a/M = J/M{sup 2} = +0.9 (prograde disk). The black hole is then instantaneously tilted, through a change in the metric, by an angle {beta}{sub 0}. In this Letter we report results with {beta}{sub 0} = 0, 15, and 30{sup o}. The disk is allowed to respond to the Lense-Thirring precession of the tilted black hole. We find that the disk settles into a quasi-static, twisted, warped configuration with Lense-Thirring precession dominating out to a radius analogous to the Bardeen-Petterson transition in tilted Keplerian disks.

  9. Atlas of Tilted Accretion Disks & Source to Negative Superhumps

    CERN Document Server

    Montgomery, M M

    2009-01-01

    Using smoothed particle hydrodynamics, we numerically simulate steady state accretion discs for Cataclysmic Variable Dwarf Novae systems that have a secondary-to-primary mass ratio (0.35 \\le q \\le 0.55). After these accretion discs have come to quasi-equilibrium, we rotate each disc out of the orbital plane by (\\delta = (1, 2, 3, 4, 5,) or (20)^{o}) to induce negative superhumps. For accretion discs tilted $5^{o}$, we generate light curves and associated Fourier transforms for an atlas on negative superhumps and retrograde precession. Our simulation results suggest that accretion discs need to be tilted more than three degrees for negative superhumps to be statistically significant. We also show that if the disc is tilted enough such that the gas stream strikes a disc face, then a dense cooling ring is generated near the radius of impact. In addition to the atlas, we study these artificially tilted accretion discs to find the source to negative superhumps. Our results suggest that the source is additional lig...

  10. Photoluminescence of a High Mobility 2DEG in the Fractional Quantum Hall Effect Regime

    Science.gov (United States)

    Smirnov, D.; Rudenkov, V. V.; Ashkinadze, B. M.; Cohen, E.; Christianen, P. C. M.; Maan, J. C.; Pfeiffer, L. N.

    The magneto-PL spectra of modulation-doped, ultra-high mobility GaAs/AlGaAs single heterojunctions (HJs) were studied under a perpendicularly applied magnetic field up to 33 T and at temperatures of 0.3 and 1.2 K. The spectra show remarkable intensity redistribution between free (bulk) exciton and 2DEG-hole PL channels occurring at electron filling factors, ν = 2 and 1. At 0.3 K, significant 2DEG-hole PL spectral changes are observed near ν = 2/3 and 1/3. Several heterojunctions with 2DEG density in the range of n2D - (1 - 2.7) · 1011 cm-2 display similar features. These spectral peculiarities are attributed to the modification of the 2DEG energy spectrum caused by the e-e interaction, in particular, the recombination of valence hole with the composite (fractionally-charged) particles of the magnetized 2DEG. In HJs with lower n2D < 1011 cm-2, the observed PL evolution at ν < 1 is mainly determined by an intensity redistribution between the σ+ and σ- circularly-polarized free exciton PL components. In this case, the exciton energy is lower than the energy of the 2DEG-hole system, so that the free excitons do not dissociate near the magnetized 2DEG and thus, the 2DEG-hole PL is barely observed.

  11. Accelerated transformation of brushite to octacalcium phosphate in new biomineralization media between 36.5 deg. C and 80 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Temizel, Neslihan; Girisken, Giray; Tas, A. Cuneyt, E-mail: cuneyt-tas@ouhsc.edu

    2011-07-20

    This study investigated the hydrothermal transformation of brushite (dicalcium phosphate dihydrate, DCPD, CaHPO{sub 4}.2H{sub 2}O) into octacalcium phosphate (OCP, Ca{sub 8}(HPO{sub 4}){sub 2}(PO{sub 4}){sub 4}.5H{sub 2}O) in seven different newly developed biomineralization media, all inspired from the commercial DMEM solutions, over the temperature range of 36.5 deg. C to 90 deg. C with aging times varying between 1 h and 6 days. DCPD powders used in this study were synthesized in our laboratory by using a wet-chemical technique. DCPD was found to transform into OCP in the Ca{sup 2+}, Mg{sup 2+}, Na{sup +}, K{sup +}, HCO{sub 3}{sup -}, Cl{sup -} and H{sub 2}PO{sub 4}{sup -} containing aqueous biomineralization media in less than 72 h at 36.5 deg. C, without stirring. The same medium was able to convert DCPD into OCP in about 2 h at 75-80 deg. C, again without a need for stirring. Samples were characterized by using powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). - Research highlights: {yields} New biomineralization solutions developed to convert DCPD into OCP at 36.5 deg. C to 80 deg. C. {yields} DCPD powder was the starting material. {yields} OCP was synthesized under static conditions (no need for stirring). {yields} OCP was synthesized in sealed glass media bottles in solutions free of Hepes or Tris. {yields} OCP can be synthesized at 75-80 deg. C in only 2 hours in the above solutions without stirring.

  12. Flexure fatigue testing of 90 deg graphite/epoxy composites

    Science.gov (United States)

    Peck, Ann Nancy W.

    1995-01-01

    3-point flexure tests of 90 deg graphite/epoxy specimens. Investigations will include the volume scale effect as well as frequency and span-to-thickness ratio effects. Prior to the start of the experimental study, an analytical study using finite element modeling will be performed to investigate the span-to-thickness effect. The ratio of transverse flexure stress to shear stress will be monitored and its values predicted by the FEM analysis compared with the value obtained using a 'strength of materials' based approach.

  13. AtDeg2 – a chloroplast protein with dual protease/chaperone activity

    Directory of Open Access Journals (Sweden)

    Przemysław Jagodzik

    2014-07-01

    Full Text Available Chloroplast protease AtDeg2 (an ATP-independent serine endopeptidase is cytosolically synthesized as a precursor, which is imported into the chloroplast stroma and deprived of its transit peptide. Then the mature protein undergoes routing to its functional location at the stromal side of thylakoid membrane. In its linear structure AtDeg2 molecule contains the protease domain with catalytic triad (HDS and two PDZ domains (PDZ1 and PDZ2. In vivo AtDeg2 most probably exists as a supposedly inactive haxamer, which may change its oligomeric stage to form active 12-mer, or 24-mer. AtDeg2 has recently been demonstrated to exhibit dual protease/chaperone function. This review is focused on the current awareness with regard to AtDeg2 structure and functional significance.

  14. Patologie sociali, resistenze e difese degli insegnanti nell’istituzione scolastica: Considerazioni cliniche e pedagogiche

    Directory of Open Access Journals (Sweden)

    Tommaso Fratini

    2014-12-01

    Full Text Available L’articolo prende in esame il tema di alcune resistenze e difese degli insegnanti all’interno dell’istituzione scolastica. Partendo dall’attuale condizione di emergenza della scuola italiana e rifacendosi al concetto di patologia sociale di Giuseppe Di Chiara, viene argomentato come tali resistenze coprano le angosce persecutorie degli insegnanti nel loro lavoro scolastico quotidiano nel rapporto con gli allievi. L’articolo, tra le varie forme di patologia istituzionale, affronta principalmente il tema di quelle che presiedono alle resistenze degli insegnanti al lavoro introspettivo con il proprio mondo interno, conseguenza e ulteriore cagione di sensi di colpa nel rapporto con gli allievi e di fenomeni di burnout lavorativo degli stessi insegnanti. Tali fenomeni vanno nella direzione del rinforzo sia di un atteggiamento di chiusura verso la collaborazione con professionisti esterni all’istituzione scolastica, sia di un atteggiamento di minore empatia e vicinanza emotiva con la realtà interna degli allievi.

  15. Tilt-table testing as a predictor of + GZ tolerance

    Directory of Open Access Journals (Sweden)

    Zawadzka-Bartczak E

    2005-11-01

    Full Text Available BACKGROUND: G-tolerance assessment is an essential element of both military pilot and pilot candidate evaluation. AIMS: Attempt at prediction of individual relaxed + Gz tolerance on the basis of head-up tilt (HUT testing. SETTINGS AND DESIGN: In two stages, 20 healthy men at the mean age 21.5 years took part in this study. The first stage, a 45 min, HUT test was performed using the Westminster protocol. During the second stage each underwent a centrifuge evaluation in response to gradual onset rate profiles. METHODS AND MATERIAL: In each subject, heart rate (HR and blood pressure (BP before and at 2, 15 and 45 min of the tilt-test were recorded. The gravity-load centrifuge (GOR studies were carried out [following the standard GOR programme, at 0.1 G/s rate of gravity load increase until the gravity load tolerance limit (loss of peripheral vision was reached]. STATISTICAL ANALYSIS USED: Relationships between variables were explored using Kendall′s tau-B correlation coefficient. The critical P-level was one-tailed 0.05. RESULTS: In four of 20 subjects (20%, vasovagal syncope occurred during the tilt test. G-level tolerance of this group (of +Gz accelerations lay in the range from +4 to +8.1 Gz, (+5.72 ? 0.86 Gz average and was comparable to the group without syncope. Loss of consciousness did not occur in any subjects during the centrifuge test. No statistically significant correlation was observed between HR and BP during tilt test and tolerance to +Gz accelerations. CONCLUSIONS: The result of tilt testing, carried out according to the Westminster protocol, was not useful in predicting individual tolerance to +Gz gravity loads.

  16. Cataract Surgery for Tilted Lens in Peters' Anomaly Type 2

    Directory of Open Access Journals (Sweden)

    Tadayuki Nishide

    2013-09-01

    Full Text Available Background: Cases of cataract surgery without penetrating keratoplasty in patients with Peters' anomaly are very rare. We report a case of Peters' anomaly type 2 with tilted lens due to synechia between the lens and iris that was treated with cataract surgery without penetrating keratoplasty. Case Presentation: A 16-year-old girl had Peters' anomaly in both eyes. Corneal opacity was severe in the left eye due to high-grade dysgenesis of the anterior segment. In the right eye, corneal opacity had spread from the center of the cornea to the inferotemporal side, and there was synechia between the iris and corneal endothelium from the inferonasal side to the inferotemporal side. Opacity was observed in the anterior pole of the lens, and there was synechia between the anterior iris and the lens. Ultrasound biomicroscopy (UBM revealed that the lens was tilted because of synechia. The tilted lens induced astigmatism, which reduced visual acuity to 20/250, in conjunction with a cataract. Cataract surgery was performed; the synechia between the lens capsule and the iris was severed, an intraocular lens was inserted, and the tilt was repaired. UBM was used postoperatively to confirm that the lens capsule synechia had been corrected and that the intraocular lens was not tilted. As a result, visual acuity improved to 20/100; glaucoma and expansion of corneal opacity were not observed. Conclusions: Severing of the synechia between the cataract and iris, during cataract surgery, in a patient with Peters' anomaly type 2 resulted in favorable postoperative visual acuity.

  17. Modeling Flow Past a Tilted Vena Cava Filter

    Energy Technology Data Exchange (ETDEWEB)

    Singer, M A; Wang, S L

    2009-06-29

    Inferior vena cava filters are medical devices used to prevent pulmonary embolism (PE) from deep vein thrombosis. In particular, retrievable filters are well-suited for patients who are unresponsive to anticoagulation therapy and whose risk of PE decreased with time. The goal of this work is to use computational fluid dynamics to evaluate the flow past an unoccluded and partially occluded Celect inferior vena cava filter. In particular, the hemodynamic response to thrombus volume and filter tilt is examined, and the results are compared with flow conditions that are known to be thrombogenic. A computer model of the filter inside a model vena cava is constructed using high resolution digital photographs and methods of computer aided design. The models are parameterized using the Overture software framework, and a collection of overlapping grids is constructed to discretize the flow domain. The incompressible Navier-Stokes equations are solved, and the characteristics of the flow (i.e., velocity contours and wall shear stresses) are computed. The volume of stagnant and recirculating flow increases with thrombus volume. In addition, as the filter increases tilt, the cava wall adjacent to the tilted filter is subjected to low velocity flow that gives rise to regions of low wall shear stress. The results demonstrate the ease of IVC filter modeling with the Overture software framework. Flow conditions caused by the tilted Celect filter may elevate the risk of intrafilter thrombosis and facilitate vascular remodeling. This latter condition also increases the risk of penetration and potential incorporation of the hook of the filter into the vena caval wall, thereby complicating filter retrieval. Consequently, severe tilt at the time of filter deployment may warrant early clinical intervention.

  18. Novel tilt-curvature coupling in lipid membranes

    Science.gov (United States)

    Terzi, M. Mert; Deserno, Markus

    2017-08-01

    On mesoscopic scales, lipid membranes are well described by continuum theories whose main ingredients are the curvature of a membrane's reference surface and the tilt of its lipid constituents. In particular, Hamm and Kozlov [Eur. Phys. J. E 3, 323 (2000)] have shown how to systematically derive such a tilt-curvature Hamiltonian based on the elementary assumption of a thin fluid elastic sheet experiencing internal lateral pre-stress. Performing a dimensional reduction, they not only derive the basic form of the effective surface Hamiltonian but also express its emergent elastic couplings as trans-membrane moments of lower-level material parameters. In the present paper, we argue, though, that their derivation unfortunately missed a coupling term between curvature and tilt. This term arises because, as one moves along the membrane, the curvature-induced change of transverse distances contributes to the area strain—an effect that was believed to be small but nevertheless ends up contributing at the same (quadratic) order as all other terms in their Hamiltonian. We illustrate the consequences of this amendment by deriving the monolayer and bilayer Euler-Lagrange equations for the tilt, as well as the power spectra of shape, tilt, and director fluctuations. A particularly curious aspect of our new term is that its associated coupling constant is the second moment of the lipid monolayer's lateral stress profile—which within this framework is equal to the monolayer Gaussian curvature modulus, κ¯ m. On the one hand, this implies that many theoretical predictions now contain a parameter that is poorly known (because the Gauss-Bonnet theorem limits access to the integrated Gaussian curvature); on the other hand, the appearance of κ¯ m outside of its Gaussian curvature provenance opens opportunities for measuring it by more conventional means, for instance by monitoring a membrane's undulation spectrum at short scales.

  19. Temperature dependent dynamics of DegP-trimer: A molecular dynamics study.

    Science.gov (United States)

    Rai, Nivedita; Ramaswamy, Amutha

    2015-01-01

    DegP is a heat shock protein from high temperature requirement protease A family, which reacts to the environmental stress conditions in an ATP independent way. The objective of the present analysis emerged from the temperature dependent functional diversity of DegP between chaperonic and protease activities at temperatures below and above 28 °C, respectively. DegP is a multimeric protein and the minimal functional unit, DegP-trimer, is of great importance in understanding the DegP pathway. The structural aspects of DegP-trimer with respect to temperature variation have been studied using molecular dynamics simulations (for 100 ns) and principal component analysis to highlight the temperature dependent dynamics facilitating its functional diversity. The DegP-trimer revealed a pronounced dynamics at both 280 and 320 K, when compared to the dynamics observed at 300 K. The LA loop is identified as the highly flexible region during dynamics and at extreme temperatures, the residues 46-80 of LA loop express a flip towards right (at 280) and left ( at 320 K) with respect to the fixed β-sheet connecting the LA loop of protease for which Phe46 acts as one of the key residues. Such dynamics of LA loop facilitates inter-monomeric interaction with the PDZ1 domain of the neighbouring monomer and explains its active participation when DegP exists as trimer. Hence, the LA loop mediated dynamics of DegP-trimer is expected to provide further insight into the temperature dependent dynamics of DegP towards the understanding of its assembly and functional diversity in the presence of substrate.

  20. Temperature dependent dynamics of DegP-trimer: A molecular dynamics study

    Directory of Open Access Journals (Sweden)

    Nivedita Rai

    2015-01-01

    Full Text Available DegP is a heat shock protein from high temperature requirement protease A family, which reacts to the environmental stress conditions in an ATP independent way. The objective of the present analysis emerged from the temperature dependent functional diversity of DegP between chaperonic and protease activities at temperatures below and above 28 °C, respectively. DegP is a multimeric protein and the minimal functional unit, DegP-trimer, is of great importance in understanding the DegP pathway. The structural aspects of DegP-trimer with respect to temperature variation have been studied using molecular dynamics simulations (for 100 ns and principal component analysis to highlight the temperature dependent dynamics facilitating its functional diversity. The DegP-trimer revealed a pronounced dynamics at both 280 and 320 K, when compared to the dynamics observed at 300 K. The LA loop is identified as the highly flexible region during dynamics and at extreme temperatures, the residues 46–80 of LA loop express a flip towards right (at 280 and left ( at 320 K with respect to the fixed β-sheet connecting the LA loop of protease for which Phe46 acts as one of the key residues. Such dynamics of LA loop facilitates inter-monomeric interaction with the PDZ1 domain of the neighbouring monomer and explains its active participation when DegP exists as trimer. Hence, the LA loop mediated dynamics of DegP-trimer is expected to provide further insight into the temperature dependent dynamics of DegP towards the understanding of its assembly and functional diversity in the presence of substrate.

  1. Graded mutation in cluster categories coming from hereditary categories with a tilting object

    CERN Document Server

    Bertani-Økland, Marco Angel; Wrålsen, Anette

    2010-01-01

    We present a graded mutation rule for quivers of cluster-tilted algebras. Furthermore, we give a technique to recover a cluster-tilting object from its graded quiver in the cluster category of coh $\\mathbb{X}$.

  2. Cross-Modal Transfer of the Tilt Aftereffect From Vision to Touch

    Science.gov (United States)

    Krystallidou, Dafni

    2016-01-01

    Visual input powerfully modulates the dynamics of tactile orientation perception. This study investigated the transfer of the tilt aftereffect (TAE) from vision to somatosensation. In a visual tilt adaptation paradigm, participants were exposed to clockwise or anticlockwise visual tilt, followed by three brief tactile two-point stimuli delivered on their forehead. In a two-alternative forced choice task, participants had to indicate whether the haptic stimulus was tilted to the right or left. Repeated exposure to oriented visual gratings produced a tactile TAE, such that the subsequent tactile stimuli appeared tilted toward the opposite direction. To assess the origin of this effect, the experiment was repeated with the head tilted. Adaptation to a gravitationally tilted grating but with the head tilted so that the grating was retinally vertical induced a robust tactile aftereffect suggesting that the visuotactile TAE is due to spatiotopic rather than retinotopic adaptation.

  3. Conceptual Design of a Two Spool Compressor for the NASA Large Civil Tilt Rotor Engine

    Science.gov (United States)

    Veres, Joseph P.; Thurman, Douglas R.

    2010-01-01

    This paper focuses on the conceptual design of a two spool compressor for the NASA Large Civil Tilt Rotor engine, which has a design-point pressure ratio goal of 30:1 and an inlet weight flow of 30.0 lbm/sec. The compressor notional design requirements of pressure ratio and low-pressure compressor (LPC) and high pressure ratio compressor (HPC) work split were based on a previous engine system study to meet the mission requirements of the NASA Subsonic Rotary Wing Projects Large Civil Tilt Rotor vehicle concept. Three mean line compressor design and flow analysis codes were utilized for the conceptual design of a two-spool compressor configuration. This study assesses the technical challenges of design for various compressor configuration options to meet the given engine cycle results. In the process of sizing, the technical challenges of the compressor became apparent as the aerodynamics were taken into consideration. Mechanical constraints were considered in the study such as maximum rotor tip speeds and conceptual sizing of rotor disks and shafts. The rotor clearance-to-span ratio in the last stage of the LPC is 1.5% and in the last stage of the HPC is 2.8%. Four different configurations to meet the HPC requirements were studied, ranging from a single stage centrifugal, two axi-centrifugals, and all axial stages. Challenges of the HPC design include the high temperature (1,560deg R) at the exit which could limit the maximum allowable peripheral tip speed for centrifugals, and is dependent on material selection. The mean line design also resulted in the definition of the flow path geometry of the axial and centrifugal compressor stages, rotor and stator vane angles, velocity components, and flow conditions at the leading and trailing edges of each blade row at the hub, mean and tip. A mean line compressor analysis code was used to estimate the compressor performance maps at off-design speeds and to determine the required variable geometry reset schedules of the

  4. Lesion classification using 3D skin surface tilt orientation.

    Science.gov (United States)

    She, Zhishun; Excell, P S

    2013-02-01

    Current non-invasive diagnostic procedures to detect skin cancer rely on two-dimensional (2D) views of the skin surface. For example, the most commonly-used ABCD features are extracted from the 2D images of skin lesion. However, because the skin surface is an object in three-dimensional (3D) space, valuable additional information can be obtained from a perspective of 3D skin objects. The aim of this work is to discover the new diagnostic features by considering 3D views of skin artefacts. A surface tilt orientation parameter was proposed to quantify the skin and the lesion in 3D space. The skin pattern was first extracted from simply captured white light optical clinical (WLC) skin images by high-pass filtering. Then the directions of the projected skin lines were determined by skin pattern analysis. Next the surface tilt orientations of skin and lesion were estimated using the shape from texture technique. Finally the difference of tilt orientation in the lesion and normal skin areas, combined with the ABCD features, was used as a lesion classifier. The proposed method was validated by processing a set of images of malignant melanoma and benign naevi. The scatter plot of classification using the feature of surface tilt orientation alone showed the potential of the new 3D feature, enclosing an area of 0.78 under the ROC curve. The scatter plot of classification, combining the new feature with the ABCD features by use of Principal Component Analysis (PCA), demonstrated an excellent separation of benign and malignant lesions. An ROC plot for this case enclosed an area of 0.85. Compared with the ABCD analysis where the area under the ROC curve was 0.65, it indicated that the surface tilt orientation (3D information) was able to enhance the classification results significantly. The initial classification results show that the surface tilt orientation has a potential to increase lesion classifier accuracy. Combined with the ABCD features, it is very promising to

  5. Effect of tilting on cerebral hemodynamics in preterm and term infants

    NARCIS (Netherlands)

    Pichler, G; van Boetzelar, MC; Muller, W; Urlesberger, B

    2001-01-01

    Tilting is known to cause changes in hemodynamics due to hydrostatic pressure. The present study is an analysis of changes in cerebral hemodynamics measured by near infrared spectroscopy (NIRS) following tilting up and down in preterm and term infants. A significantly different effect of tilting up

  6. Using Paraffin with -10 deg C to 10 deg C Melting Point for Payload Thermal Energy Storage in SpaceX Dragon Trunk

    Science.gov (United States)

    Choi, Michael K.

    2013-01-01

    A concept of using paraffin wax phase change material (PCM) with a melting point between -10 deg C and 10 deg C for payload thermal energy storage in a Space Exploration Technologies (SpaceX) Dragon trunk is presented. It overcomes the problem of limited heater power available to a payload with significant radiators when the Dragon is berthed to the International Space Station (ISS). It stores adequate thermal energy to keep a payload warm without power for 6 hours during the transfer from the Dragon to an ExPRESS logistics carrier (ELC) on the ISS.

  7. Far-infrared and submillimeter survey of the galactic plane from l = 11.5 deg to l = 17.5 deg

    Science.gov (United States)

    Campbell, M. F.; Niles, D. W.; Silverberg, R. F.; Hauser, M. G.; Stier, M. T.; Kelsall, T.; Hoffmann, W. F.; Thronson, H. A., Jr.

    1984-01-01

    Medium resolution (11 min) maps of the galactic plane are presented from l = 11.5 deg to l = 17.5 deg at wavelengths of 93 microns, 154 microns, and 190 microns. The maps are interpreted in terms of the temperature and spatial structure of diffuse far-infrared/submillimeter sources associated with evolved H II regions and a continuous ridge of galactic emission. The emission regions are found to be more extended at the longer wavelengths which implies that there must be a range of dust temperatures in the sources. The properties of the galactic ridge are similar to those of the sources.

  8. Three-Dimensional Waves in Tilt Thermal Boundary Layers

    Institute of Scientific and Technical Information of China (English)

    TAO Jian-Jun; YUAN Xiang-Jiang

    2009-01-01

    We numerically and theoretically study the stabilities of tilt thermal boundary layers immersed in stratified air. An interesting phenomenon is revealed: the stationary longitudinal-roll mode becomes unstable to some oscillating state even when the Grashof number is smaller than its corresponding critical value. By stability analysis, this phenomenon is explained in terms of a new three-dimensional wave mode. The effect of the tilt angle on the stability of the boundary flows is investigated. Since the new three-dimensional wave is found to be the most unstable mode when the title angle is between 30° and 64°, it is expected to play an important role in the transition to turbulence.

  9. Tilting-Pad Guide Bearing in Large Hydro-unit

    Directory of Open Access Journals (Sweden)

    Li-Feng Ma

    2000-01-01

    Full Text Available A new numerical method is proposed for predicting the nonlinearity of tilting-pad guide bearing oilfilm force in the rotor-bearing system in a large hydro-unit. Nonlinear displacement and velocity of the journal center, as well as nonlinear tilting angles and angular velocities of the pads in non-stationary Reynolds equation are taken into account. This method is also suited for other small rotor-bearing system. As an example, the response due to a momentarily created unbalance is Calculated. The nonlinear motion patterns of the pad and journal whirling orbit are obtained. Finally, the nonlinear orbit is compared to the linear one that could be calculated from linear stiffness and damping coefficients. It is shown that there are important differences between those two orbits and that the nonlinear simulation is more accurate.

  10. Atomic arrangement and charge distribution in YBCO tilt grain boundaries

    Science.gov (United States)

    Bording, J. K.; Halley, J. W.; Zhu, Y.

    2005-03-01

    It is well known that the critical current, Jc, in high-Tc superconductors is reduced at grain boundaries. Recent high resolution holography experiments show the [100] tilt grain boundaries in YBa2Cu3O7-x to have an excess negative charge localized at the boundary dislocation core. Upon doping with Ca, this charge is reduced and the critical current increased. To shed light on this behavior at an atomic scale, we carried out Tight Binding (TB) calculations of these boundaries. Our TB scheme is charge self consistent to allow charge transfer typical for ionic materials. We present the arrangement of atoms and charge in YBCO tilt grain boundaries as determined by a combination of TB calculations, recent high resolution Scanning Transmission Electron Microscopy and Electron Energy Loss Spectroscopy measurements.

  11. Tilt correction method of text image based on wavelet pyramid

    Science.gov (United States)

    Yu, Mingyang; Zhu, Qiguo

    2017-04-01

    Text images captured by camera may be tilted and distorted, which is unfavorable for document character recognition. Therefore,a method of text image tilt correction based on wavelet pyramid is proposed in this paper. The first step is to convert the text image captured by cameras to binary images. After binarization, the images are layered by wavelet transform to achieve noise reduction, enhancement and compression of image. Afterwards,the image would bedetected for edge by Canny operator, and extracted for straight lines by Radon transform. In the final step, this method calculates the intersection of straight lines and gets the corrected text images according to the intersection points and perspective transformation. The experimental result shows this method can correct text images accurately.

  12. Tilted Foils Nuclear Spin Polarization at REX-ISOLDE

    CERN Document Server

    Törnqvist, Hans Toshihide

    2013-08-08

    This thesis will explain and summarize my work and involvement in experiments aimed at producing nuclear spin polarization of post-accelerated beams of ions with the tilted-foils technique at the REX-ISOLDE linear accelerator at CERN. Polarizing the nuclear spin of radioactive beams in particular may provide access to observables which may be difficult to obtain otherwise. Currently, the techniques commonly employed for nuclear spin polarization are restricted to specific nuclides and experimental measurement techniques. Tilted foils polarization may provide a new tool to extend the range of nuclides that can be polarized and the types of experiments that can be performed. The experiments rely not only on the production but also on the method to measure the degree of attained polarization. Two methods will be treated, based on particle scattering in Coulomb excitation that may be utilized for stable beams, and the $\\beta$-NMR that requires $\\beta$-decaying nuclei. The experimental setups and measurements will...

  13. Profile stabilization of tilt mode in a Field Reversed Configuration

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, J.W.; Tajima, T. [Texas Univ., Austin, TX (United States). Inst. for Fusion Studies; Barnes, D.C. [Los Alamos National Lab., NM (United States)

    1993-06-01

    The possibility of stabilizing the tilt mode in Field Reversed Configurations without resorting to explicit kinetic effects such as large ion orbits is investigated. Various pressure profiles, P({Psi}), are chosen, including ``hollow`` profiles where current is strongly peaked near the separatrix. Numerical equilibria are used as input for an initial value simulation which uses an extended Magnetohydrodynamic (MHD) model that includes viscous and Hall terms. Tilt stability is found for specific hollow profiles when accompanied by high values of separatrix beta, {beta}{sub sep}. The stable profiles also have moderate to large elongation, racetrack separatrix shape, and lower values of 3, average ratio of Larmor radius to device radius. The stability is unaffected by changes in viscosity, but the neglect of the Hall term does cause stable results to become marginal or unstable. Implications for interpretation of recent experiments are discussed.

  14. On the Design of Tilting-Pad Thrust Bearings

    DEFF Research Database (Denmark)

    Heinrichson, Niels

    2007-01-01

    Pockets are often machined in the surfaces of tilting-pad thrust bearings to allow for hydrostatic jacking in the start-up phase. Pockets and other recesses in the surfaces of bearing pads influence the pressure distribution and thereby the position of the pivot resulting in the most advantageous...... friction and a small pressure build-up. As in parallel-step bearings the recesses may also have a depth of the same order of magnitude as the oil film thickness. Such recesses are characterized by a strong pressure build-up caused by the reduction of the flow area at the end of the recess. Numerical models...... based on the Reynolds equation are used. They include the effects of variations of viscosity with temperature and the deformation of the bearing pads due to pressure and thermal gradients. The models are validated using measurements. Tilting-pad bearings of standard design are studied and the influences...

  15. Quantification of metallic iodides in fucus vesiculosus and serratus heated at 80 deg, 550 deg and 1 000 deg; Quantification des iodures metalliques dans des cendres d'algues. Analyse de fucus vesiculosus et serratus chauffees a 80 degres, 550 degre et 1000 degre

    Energy Technology Data Exchange (ETDEWEB)

    Aujollet, Y. [Direction Generale de la Surete Nucleaire et de la Radioprotection (DGSNR), 75 - Paris (France)

    2004-02-01

    Metallic iodides in aqueous phase of Fucus ashes were measured by gamma spectrometry. Before the measurements, different samples of Fucus were heated at 80 deg C (Fucus vesiculosus), 550 deg C (Fucus serratus) and 1 000 deg C (Fucus serratus). The first results gave 63% of iodide salts in Fucus vesiculosus heated at 80 deg C, 27% of iodide salts in Fucus serratus (550 deg C) and no result for ashes of Fucus serratus heated at 1 000 deg C, because there was not enough mass of product for a good analysis by gamma spectrometry. (author)

  16. Can pelvic tilting be ignored in total hip arthroplasty?

    Directory of Open Access Journals (Sweden)

    Won Yong Shon

    2014-01-01

    CONCLUSION: The sagittal position of pelvis is a key factor in impingement and dislocation after total hip arthroplasty. Pelvic tilting affects the position of acetabular component in the sagittal plane of the body as compared with its anatomic position in the pelvis. We suggest a preoperative lateral view of spine-pelvis, in upright and supine position for evaluation of a corrective adaptation of the acetabular cup accordingly with pelvic balance.

  17. An entry in the great frame-tilt judging contest.

    Science.gov (United States)

    Goodenough, D R

    1981-02-01

    Some important questions about discrepancies between observer-perceived and investigator-defined direction of frame tilt are raised by Fine in his recent note on procedures used in the rod-and-frame test of field dependence. The practical and conceptual implications of these discrepancies are discussed in the present article in the context of Witkin's field-dependence theory and of recent findings on the nature of the rod-and-frame illusion.

  18. Linear Coupling for B-Factory Tilted Solenoid

    Energy Technology Data Exchange (ETDEWEB)

    Fedotov, A.

    2005-02-16

    In this thesis they have presented the transfer matrix for B Factory tilted solenoid with the expansion of magnetic field up to the fifth order. Starting with the general theory of linear coupling, we got the Hamiltonian for solenoid with the bending magnet and quadrupole inside. The solenoid axis is tilted by 20 mrad horizontally w.r.t. the collision axis and at the entrance and the exit of the solenoid the beam will sense transverse and longitudinal non-linear fields. To account both this effects the expansion of the magnetic field was done. The code of coordinate transformation, which relates the frame of the reference orbit to the frame of the collision axis and to the solenoid frame, has been introduced. They tried to show that not symplectic fourth-order Runge Kutta integration method, which had been used for integration of the Hamiltonian equations, might be used as a model for ''not tracking'' problems. The deviation from a symplectic transfer matrix is smaller than 10{sup -5}. Using the transfer matrix, the change in beam shape and blow up of emittance, due to the solenoid coupling, was discussed. In order to compensate this effect they used 4 tilted quadrupoles on each side of the IP. The method based on the Hamiltonian in Eq.19 integrates along a reference orbit which is defined only by the horizontal and vertical bending fields and not by the tilted solenoid. In order to get the Hamiltonian, which is associated with a non-planar curvature of the reference orbit, it is necessary to account the effect of torsion. In that case the transformation between the three different coordinate systems will become more complicated.

  19. Carbon dioxide waveguide lasers with folds and tilted mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Hill, C.A.; Jackson, P.E. (Heriot-Watt University, Physics Department, Optoelectronics Lasar Engineering, Edinburgh EH14 4AS, U.K. (GB)); Hall, D. (Royal Signals Radar Establishment, Malvern, Worcs WR14 3PS, (UK))

    1990-05-20

    We present theoretical and experimental results for an rf-excited z-fold CO{sub 2} waveguide laser. We describe how the output power, output rotational line(s) and transverse mode(s) vary as functions of elbow mirror tilt and obtain good agreement with predictions from a multimode matrix resonator model. Observations of multilining and/or multifrequency operation are partly explained by the near equality of gain/loss ratios for two or more resonator modes.

  20. Upper Body Venous Compliance Exceeds Lower Body Venous Compliance in Humans

    Science.gov (United States)

    Watenpaugh, Donald E.

    1996-01-01

    Human venous compliance hypothetically decreases from upper to lower body as a mechanism for maintenance of the hydrostatic indifference level 'headward' in the body, near the heart. This maintains cardiac filling pressure, and thus cardiac output and cerebral perfusion, during orthostasis. This project entailed four steps. First, acute whole-body tilting was employed to alter human calf and neck venous volumes. Subjects were tilted on a tilt table equipped with a footplate as follows: 90 deg, 53 deg, 30 deg, 12 deg, O deg, -6 deg, -12 deg, -6 deg, O deg, 12 deg, 30 deg, 53 deg, and 90 deg. Tilt angles were held for 30 sec each, with 10 sec transitions between angles. Neck volume increased and calf volume decreased during head-down tilting, and the opposite occurred during head-up tilt. Second, I sought to cross-validate Katkov and Chestukhin's (1980) measurements of human leg and neck venous pressures during whole-body tilting, so that those data could be used with volume data from the present study to calculate calf and neck venous compliance (compliance = (Delta)volume/(Delta)pressure). Direct measurements of venous pressures during postural chances and whole-body tilting confirmed that the local changes in venous pressures seen by Katkov and Chestukhin (1980) are valid. The present data also confirmed that gravitational changes in calf venous pressure substantially exceed those changes in upper body venous pressure. Third, the volume and pressure data above were used to find that human neck venous compliance exceeds calf venous compliance by a factor of 6, thereby upholding the primary hypothesis. Also, calf and neck venous compliance correlated significantly with each other (r(exp 2) = 0.56). Fourth, I wished to determine whether human calf muscle activation during head-up tilt reduces calf venous compliance. Findings from tilting and from supine assessments of relaxed calf venous compliance were similar, indicating that tilt-induced muscle activation is

  1. Tilting mutation of weakly symmetric algebras and stable equivalence

    CERN Document Server

    Dugas, Alex

    2011-01-01

    We consider tilting mutations of a weakly symmetric algebra at a subset of simple modules, as recently introduced by T. Aihara. These mutations are defined as the endomorphism rings of certain tilting complexes of length 1. Starting from a weakly symmetric algebra A, presented by a quiver with relations, we give a detailed description of the quiver and relations of the algebra obtained by mutating at a single loopless vertex of the quiver of A. In this form the mutation procedure appears similar to, although significantly more complicated than, the mutation procedure of Derksen, Weyman and Zelevinsky for quivers with potentials. By definition, weakly symmetric algebras connected by a sequence of tilting mutations are derived equivalent, and hence stably equivalent. The second aim of this article is to describe explicitly the images of the simple modules under such a stable equivalence. As an application we answer a question of Asashiba on the derived Picard groups of a class of symmetric algebras of finite re...

  2. Modeling of Tilting-Pad Journal Bearings with Transfer Functions

    Directory of Open Access Journals (Sweden)

    J. A. Vázquez

    2001-01-01

    Full Text Available Tilting-pad journal bearings are widely used to promote stability in modern rotating machinery. However, the dynamics associated with pad motion alters this stabilizing capacity depending on the operating speed of the machine and the bearing geometric parameters, particularly the bearing preload. In modeling the dynamics of the entire rotor-bearing system, the rotor is augmented with a model of the bearings. This model may explicitly include the pad degrees of freedom or may implicitly include them by using dynamic matrix reduction methods. The dynamic reduction models may be represented as a set of polynomials in the eigenvalues of the system used to determine stability. All tilting-pad bearings can then be represented by a fixed size matrix with polynomial elements interacting with the rotor. This paper presents a procedure to calculate the coefficients of polynomials for implicit bearing models. The order of the polynomials changes to reflect the number of pads in the bearings. This results in a very compact and computationally efficient method for fully including the dynamics of tilting-pad bearings or other multiple degrees of freedom components that interact with rotors. The fixed size of the dynamic reduction matrices permits the method to be easily incorporated into rotor dynamic stability codes. A recursive algorithm is developed and presented for calculating the coefficients of the polynomials. The method is applied to stability calculations for a model of a typical industrial compressor.

  3. Tilted Two-Dimensional Array Multifocus Confocal Raman Microspectroscopy.

    Science.gov (United States)

    Yabumoto, Sohshi; Hamaguchi, Hiro-O

    2017-07-18

    A simple and efficient two-dimensional multifocus confocal Raman microspectroscopy featuring the tilted-array technique is demonstrated. Raman scattering from a 4 × 4 square foci array passing through a 4 × 4 confocal pinhole array is tilted with a periscope. The tilted array of Raman scattering signals is dispersed by an imaging spectrograph onto a CCD detector, giving 16 independent Raman spectra formed as 16 bands with different heights on the sensor. Use of a state-of-the-art imaging spectrograph enables high-precision wavenumber duplicability of the 16 spectra. This high duplicability makes the simultaneously obtained spectra endurable for multivariate spectral analyses, which is demonstrated by a singular value decomposition analysis for Raman spectra of liquid indene. Although the present implementation attains only 16 measurement points, the number of points can be extended to larger than 100 without any technical leaps. Limit of parallelization depends on the interval of measurement points as well as the performance of the optical system. Criteria for finding the maximum feasible number are discussed.

  4. Tilted Lema\\^itre model and the dark flow

    CERN Document Server

    Fernández, J

    2013-01-01

    In the last years, the peculiar velocities of many X-ray galaxies clusters with respect to the distance have been measured directly in the rest frame of the cosmic microwave background radiation (CBR), using the kinematic Sunyaev-Zeldovich (kSZ) effect. These measures prove that exists a highly coherent motion, extending out to at least to ~1 Gpc, of the matter rest frame with respect to the CBR rest frame. This global motion was named "dark flow". By using an inhomogeneous spherically symmetric "tilted" Lema\\^itre model, we could explain the dark flow if we assume a linear increase with distance of the peculiar velocities, which is in principle allowed by these observations. This linear increase of the dark flow with the distance has the same behavior that the intrinsic dipole, due to the kinematic acceleration, which appears in the Hubble law of the Lema\\^itre model. In the "tilted" Lema\\^itre model considered, we consider that the radiation orthogonal congruence is a perfect fluid and the matter "tilted" c...

  5. A cardiovascular mathematical model of graded head-up tilt.

    Directory of Open Access Journals (Sweden)

    Einly Lim

    Full Text Available A lumped parameter model of the cardiovascular system has been developed and optimized using experimental data obtained from 13 healthy subjects during graded head-up tilt (HUT from the supine position to [Formula: see text]. The model includes descriptions of the left and right heart, direct ventricular interaction through the septum and pericardium, the systemic and pulmonary circulations, nonlinear pressure volume relationship of the lower body compartment, arterial and cardiopulmonary baroreceptors, as well as autoregulatory mechanisms. A number of important features, including the separate effects of arterial and cardiopulmonary baroreflexes, and autoregulation in the lower body, as well as diastolic ventricular interaction through the pericardium have been included and tested for their significance. Furthermore, the individual effect of parameter associated with heart failure, including LV and RV contractility, baseline systemic vascular resistance, pulmonary vascular resistance, total blood volume, LV diastolic stiffness and reflex gain on HUT response have also been investigated. Our fitted model compares favorably with our experimental measurements and published literature at a range of tilt angles, in terms of both global and regional hemodynamic variables. Compared to the normal condition, a simulated congestive heart failure condition produced a blunted response to HUT with regards to the percentage changes in cardiac output, stroke volume, end diastolic volume and effector response (i.e., heart contractility, venous unstressed volume, systemic vascular resistance and heart rate with progressive tilting.

  6. Analytic crack solutions for tilt fields around hydraulic fractures

    Energy Technology Data Exchange (ETDEWEB)

    Warpinski, N.R.

    2000-01-05

    The recent development of downhole tiltmeter arrays for monitoring hydraulic fractures has provided new information on fracture growth and geometry. These downhole arrays offer the significant advantages of being close to the fracture (large signal) and being unaffected by the free surface. As with surface tiltmeter data, analysis of these measurements requires the inversion of a crack or dislocation model. To supplement the dislocation models of Davis [1983], Okada [1992] and others, this work has extended several elastic crack solutions to provide tilt calculations. The solutions include constant-pressure 2D, penny-shaped, and 3D-elliptic cracks and a 2D-variable-pressure crack. Equations are developed for an arbitrary inclined fracture in an infinite elastic space. Effects of fracture height, fracture length, fracture dip, fracture azimuth, fracture width and monitoring distance on the tilt distribution are given, as well as comparisons with the dislocation model. The results show that the tilt measurements are very sensitive to the fracture dimensions, but also that it is difficult to separate the competing effects of the various parameters.

  7. In situ observations of BrO over Antarctica - ER-2 aircraft results from 54 deg S to 72 deg S latitude

    Science.gov (United States)

    Brune, W. H.; Anderson, J. G.; Chan, K. R.

    1989-01-01

    Bromine monoxide was observed in situ during nine flights of the NASA ER-2 aircraft from Punta Arenas, Chile (54 deg S latitude), to 72 deg S latitude over the Palmer Peninsula, Antarctica. The first flight for the BrO detection system was on August 28. The distribution of BrO inside the chemically perturbed region defined by greatly elevated ClO abundances was different from that found just outside. Inside, the BrO mixing ratio was 6.1 + or - 1.1 pptv above the 440 K potential temperature surface, 4.7 + or - 2.0 pptv between the 400 and 440 K surfaces, and less than 4 pptv below the 400 K surface. At high latitudes outside the chemically perturbed region, the BrO mixing ratio was 5.4 + or - 1.4 pptv near the 450 K surface, but decreased to 2.9 + or - 1.2 pptv at the 420 K surface. The abundance of BrO showed no discernible temporal trend during the course of the nine flights. Away from the south polar region, at latitudes between 47 deg S and 37 deg N and potential temperatures between 435 and 500 K (18.5- to 20.7-km altitude), the BrO mixing ratio was 0.5-3.0 pptv.

  8. Simplified 2DEG carrier concentration model for composite barrier AlGaN/GaN HEMT

    Energy Technology Data Exchange (ETDEWEB)

    Das, Palash, E-mail: d.palash@gmail.com; Biswas, Dhrubes, E-mail: d.palash@gmail.com [Indian Institute of Technology Kharagpur, Kharagpur - 721302, West Bengal (India)

    2014-04-24

    The self consistent solution of Schrodinger and Poisson equations is used along with the total charge depletion model and applied with a novel approach of composite AlGaN barrier based HEMT heterostructure. The solution leaded to a completely new analytical model for Fermi energy level vs. 2DEG carrier concentration. This was eventually used to demonstrate a new analytical model for the temperature dependent 2DEG carrier concentration in AlGaN/GaN HEMT.

  9. Strumentazione multisensore selettiva per il monitoraggio in continuo degli odori nel settore ambientale

    OpenAIRE

    Giuliani, Stefano

    2012-01-01

    2010 - 2011 L’odore indotto dall’esercizio degli impianti di ingegneria sanitaria ambientale è ritenuto la causa principale di disturbo che la popolazione residente nelle vicinanze avverte. Sebbene alle emissioni odorigene sia solo raramente associato un reale rischio tossicologico-sanitario, sia per la natura raramente pericolosa degli odoranti che per le concentrazioni generalmente molto basse, nell’immaginario collettivo, ai cattivi odori si associano spesso condizioni di “non salubrità...

  10. Experimental measurement of the solubility of bismuth phases in water vapor from 220 deg. C to 300 deg. C: Implications for ore formation

    Energy Technology Data Exchange (ETDEWEB)

    Kruszewski, Jason M. [Department of Geological Sciences, University of Idaho, Moscow, ID 83844-3022 (United States); Wood, Scott A., E-mail: swood@uidaho.edu [Department of Geological Sciences, University of Idaho, Moscow, ID 83844-3022 (United States)

    2009-04-15

    Preliminary measurements were carried out of the solubility of the O{sub 2-}buffering assemblage bismuth + bismite (Bi{sub 2}O{sub 3}) in aqueous liquid-vapor and vapor-only systems at temperatures of 220, 250 and 300 deg. C. All experiments were carried out in Ti reaction vessels and were designed such that the Bi solids were contained in a silica tube that prevented contact with liquid water at any time during the experiment. Two blank (no Bi solids present) liquid-vapor experiments at 220 deg. C yielded Bi concentrations ({+-}1{sigma}) in the condensed liquid of 0.22 {+-} 0.02 mg/L, whereas the solubility measurements at this temperature yielded an average value of approximately 6 {+-} 9 mg/L, with replicate experiments ranging from 0.3 to 26 mg/L. Although the 6 mg/L value is associated with a considerable degree of uncertainty, the experiments do indicate transport of Bi through the vapor phase. Measured Bi concentrations in the condensed liquid at 250 deg. C were in the same range as those at 220 deg. C, whereas those at 300 deg. C were significantly lower (i.e., all below the blank value). Vapor-only experiments necessarily contained much smaller initial volumes of water, thereby making the results more susceptible to contamination. Single blank runs at 220 and 300 deg. C yielded Bi concentrations of 82 and 16 mg/L, respectively. Measured concentrations ({+-}1{sigma}) of Bi in the vapor-only solubility experiments at 220 deg. C were 235 {+-} 78 mg/L for an initial water volume of 0.5 mL, and at 300 deg. C were 56 {+-} 30 mg/L and 33 {+-} 21 for initial water volumes of 1 and 2 mL, respectively, suggesting strong preferential partitioning of Bi into the vapor. The results indicate a negative dependence of Bi solubility on temperature, but are inconclusive with respect to the dependence of Bi solubility on water density or fugacity. The experiments reported here suggest that significant Bi transport is possible in the vapor phase. Comparison of the liquid

  11. Evaluation of myocardial SPECT imaging reconstructed from 270deg projection data. A study using a cardiac phantom

    Energy Technology Data Exchange (ETDEWEB)

    Kashikura, Kenichi [Japan Science and Technology Corp., Akita (Japan). Akita Lab.; Kobayashi, Hideki; Kashikura, Akemi

    1997-01-01

    SPECT reconstruction is commonly performed using 360deg or 180deg projection data. However, it is also possible to reconstruct SPECT images using other projection data arcs. The purpose of this study was to characterize images obtained by limiting the projection data to 270deg by discarding the projection views with severe attenuation. A series of phantom studies was performed with and without plastic chambers simulating perfusion defects using {sup 201}Tl and {sup 99m}Tc. Images using 270deg, 360deg, and 180deg projection arcs were identically reconstructed from the same data. In the absence of plastic chambers, intraslice uniformity in a given slice was assessed by computing the coefficient of variation (CV) of average counts in 8 ROIs within the slice. Interslice uniformity was assessed by computing the CV of average counts in five short axial slices. With plastic chambers in place, the variability in defect contrasts was assessed by computing the CV of defect contrasts in 4 chambers, located on the anterior, lateral, inferoposterior, and septal walls. The intraslice uniformity of the 270deg images were considerably inferior to those of the 360deg and 180deg images. The interslice uniformity was highest in the 360deg images, and lowest in the 180deg images. The variation in defect contrasts in the 270deg image was higher than those of the other two images. The 270deg images showed a high defect contrast in the septum and high counts in the anterior and anteroseptal wall. Because a large variation in defect contrasts within a segment might result in false positive or negative in diagnosis, 270deg imaging is not recommended over 360deg or 180deg imaging. (author)

  12. 15d-6°头低位卧床女性腰椎X线影像变化及防护效果%Alteration of X-ray Images and Countermeasure Effects in Female Lumbar Spine during 15 d -6° Head-down Bed Rest.

    Institute of Scientific and Technical Information of China (English)

    王林杰; 李莹辉; 白延强; 张丽芬; 窦跃龙; 周湘杰; 陈文娟; 袁敏; 赵琦; 刘书娟; 唐国华

    2011-01-01

    目的 研究下体负压/自行车功量计锻炼对15 d头低位卧床女性腰椎功能失调的防护作用.方法 对22名女性志愿者分为对照组(CON,n=8)、下体负压锻炼组(LBNP,n=7)、下体负压联合自行车功量计锻炼组(LBNP+ERGO,n=7),在卧床前和卧床后第4天,采用X线对脊柱状态进行了检查.分别测量并比较卧床前后腰椎总长度,每节腰椎椎间隙长度及腰椎前凸曲度的变化.结果 LBNP组卧床后L5/S1腰椎椎间隙宽度增加;CON卧床后腰椎前凸曲度降低,ERGO+LBNP组卧床后腰椎前凸曲度增加.结论 下体负压/自行车功量计锻炼可改善女性15 d头低位卧床引起的腰椎卸负荷变化.%Objective To test the counteraction effects of low body negative pressure (LBNP)/ergometer exercise on lumbar spine deconditioning of the female volunteers in 15 d head-down bed rest(HDBR).Methods Twenty-two female volunteers were randomly divided into control group (CON ,n = 8 ), LBNP group (LBNP, n = 7 ) and LBNP + ergometer group ( LBNP + ERGO, n = 7 ).They underwent X-rays assays before and 4 d after HDBR.The lumbar spine length, L1to L5 intravertebral space width and lumbar lordosis were measured and analyzed.Results LBNP caused the elongation of L5/S1 intervertebral space.Lumbar lordosis decreased after HDBR in control group, but increased in LBNP/ergometer group.Conclusion LBNP/ergometer exercises can modify the lumbar spine deconditioning associated with 15 d HDBR in women.

  13. Diagnosing postural tachycardia syndrome: comparison of tilt testing compared with standing haemodynamics.

    Science.gov (United States)

    Plash, Walker B; Diedrich, André; Biaggioni, Italo; Garland, Emily M; Paranjape, Sachin Y; Black, Bonnie K; Dupont, William D; Raj, Satish R

    2013-01-01

    POTS (postural tachycardia syndrome) is characterized by an increased heart rate (ΔHR) of ≥30 bpm (beats/min) with symptoms related to upright posture. Active stand (STAND) and passive head-up tilt (TILT) produce different physiological responses. We hypothesized these different responses would affect the ability of individuals to achieve the POTS HR increase criterion. Patients with POTS (n=15) and healthy controls (n=15) underwent 30 min of tilt and stand testing. ΔHR values were analysed at 5 min intervals. ROC (receiver operating characteristic) analysis was performed to determine optimal cut point values of ΔHR for both tilt and stand. Tilt produced larger ΔHR than stand for all 5 min intervals from 5 min (38±3 bpm compared with 33±3 bpm; P=0.03) to 30 min (51±3 bpm compared with 38±3 bpm; Pbpm criterion was similar for all tests (TILT10=93%, STAND10=87%, TILT30=100%, and STAND30=93%). Sp (specificity) of the 30 bpm criterion was less at both 10 and 30 min for tilt (TILT10=40%, TILT30=20%) than stand (STAND10=67%, STAND30=53%). The optimal ΔHR to discriminate POTS at 10 min were 38 bpm (TILT) and 29 bpm (STAND), and at 30 min were 47 bpm (TILT) and 34 bpm (STAND). Orthostatic tachycardia was greater for tilt (with lower Sp for POTS diagnosis) than stand at 10 and 30 min. The 30 bpm ΔHR criterion is not suitable for 30 min tilt. Diagnosis of POTS should consider orthostatic intolerance criteria and not be based solely on orthostatic tachycardia regardless of test used.

  14. The influence of head and body tilt on human fore-aft translation perception

    Science.gov (United States)

    Crane, Benjamin T.

    2016-01-01

    The tilt-translation ambiguity occurs because acceleration due to translation cannot be differentiated from gravitational acceleration. Head tilt can occur independent of body tilt which further complicates the problem. The tilt-translation ambiguity is examined for fore-aft (surge) translation with head and/or body orientations that are tilted in pitch 10° forward or backward. Eleven human subjects (6 female), mean age 40 years participated. Conditions included no tilt (NT), head and body tilt (HBT), head only tilt (HOT), and body only tilt (BOT). The fore-aft stimulus consisted of a 2s (0.5 Hz) sine wave in acceleration which a maximum peak velocity of 10 cm/s. After each stimulus the subject reported the direction of motion as forward or backward. Subsequent stimuli were adjusted to determine the point at which subjects were equally likely to report motion in either direction. During the HBT responses were biased such that upward pitch caused a neutral stimulus to be more likely to be perceived as forward and downward pitch caused the stimulus to be more likely to be perceived as backward. The difference in the point of subjective equality based on the direction of tilt was 3.3 cm/s. During the BOT condition the bias with respect to the direction of body tilt was in a similar direction with a difference in PSE 1.6 cm/s. During HOT and NT there was no significant bias on fore-aft perception. These findings demonstrate that body tilt shifts the PSE of fore-aft direction discrimination while head tilt has no influence. PMID:25160866

  15. Deletion of degQ gene enhances outer membrane vesicle production of Shewanella oneidensis cells.

    Science.gov (United States)

    Ojima, Yoshihiro; Mohanadas, Thivagaran; Kitamura, Kosei; Nunogami, Shota; Yajima, Reiki; Taya, Masahito

    2017-04-01

    Shewanella oneidensis is a Gram-negative facultative anaerobe that can use a wide variety of terminal electron acceptors for anaerobic respiration. In this study, S. oneidensis degQ gene, encoding a putative periplasmic serine protease, was cloned and expressed. The activity of purified DegQ was inhibited by diisopropyl fluorophosphate, a typical serine protease-specific inhibitor, indicating that DegQ is a serine protease. In-frame deletion and subsequent complementation of the degQ were carried out to examine the effect of envelope stress on the production of outer membrane vesicles (OMVs). Analysis of periplasmic proteins from the resulting S. oneidensis strain showed that deletion of degQ induced protein accumulation and resulted in a significant decrease in protease activity within the periplasmic space. OMVs from the wild-type and mutant strains were purified and observed by transmission electron microscopy. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the OMVs showed a prominent band at ~37 kDa. Nanoliquid chromatography-tandem mass spectrometry analysis identified three outer membrane porins (SO3896, SO1821, and SO3545) as dominant components of the band, suggesting that these proteins could be used as indices for comparing OMV production by S. oneidensis strains. Quantitative evaluation showed that degQ-deficient cells had a fivefold increase in OMV production compared with wild-type cells. Thus, the increased OMV production following the deletion of DegQ in S. oneidensis may be responsible for the increase in envelope stress.

  16. Focus variation microscope: linear theory and surface tilt sensitivity.

    Science.gov (United States)

    Nikolaev, Nikolay; Petzing, Jon; Coupland, Jeremy

    2016-05-01

    In a recent publication [3rd International Conference on Surface Metrology, Annecy, France, 2012, p. 1] it was shown that surface roughness measurements made using a focus variation microscope (FVM) are influenced by surface tilt. The effect appears to be most significant when the surface has microscale roughness (Ra≈50  nm) that is sufficient to provide a diffusely scattered signal that is comparable in magnitude to the specular component. This paper explores, from first principles, image formation using the focus variation method. With the assumption of incoherent scattering, it is shown that the process is linear and the 3D point spread characteristics and transfer characteristics of the instrument are well defined. It is argued that for the case of microscale roughness and through the objective illumination, the assumption of incoherence cannot be justified and more rigorous analysis is required. Using a foil model of surface scattering, the images that are recorded by a FVM have been calculated. It is shown that for the case of through-the-objective illumination at small tilt angles, the signal quality is degraded in a systematic manner. This is attributed to the mixing of specular and diffusely reflected components and leads to an asymmetry in the k-space representation of the output signals. It is shown that by using extra-aperture illumination or tilt angles greater than the acceptance angle of aperture (such that the specular component is lost), the incoherent assumption can be justified once again. The work highlights the importance of using ring-light illumination and/or polarizing optics, which are often available as options on commercial instruments, as a means to mitigate or prevent these effects.

  17. Rationale for tilted implants: FEA considerations and clinical reports.

    Science.gov (United States)

    DE Vico, G; Bonino, M; Spinelli, D; Schiavetti, R; Sannino, G; Pozzi, A; Ottria, L

    2011-07-01

    The prevalence of the elderly population, as well as life expectancy, increased in the final decades of the 20th century, as described in the World Health Organization 2004 Annual Report. The edentulous condition therefore has a negative impact on the oral health-related quality of life. Patients wearing complete dentures for many years infact, and especially in the mandible, are often unsatisfied because of the instability of the prosthesis during speaking and eating. To date dental implant treatment is well documented as a predictable treatment for partial or complete edentulism. On the other hand the rehabilitation of atrophied edentulous arches with endosseous implants (> 10 mm) in the posterior regions is often associated with anatomic problems such as bone resorption, poor bone quality, mandibular canal, and the presence of maxillary sinuses. Different procedures have been proposed to overcome these anatomic limitations. The use of tilted implants parallel to the anterior wall of the maxillary sinus or the mental foramen/inferior alveolar nerve has been proposed as a conservative solution for the treatment of the atrophic edentulous maxilla. Aim of this study was to describe, through a detailed literature review, the clinical and biomechanical rationale for tilting implants and to evaluate the long-term prognosis of immediately loaded full fixed prostheses for the treatment of edentulous patients (#35) with extreme bone atrophy rehabilited with both axial (#70) and tilted (#70) implants from 2008 to 2010. The results of the present study would suggest that this new surgical technique may reduce patient morbidity and extend the indications for immediate loading full fixed rehabilitations. This improves the predictability of treatment goal, allows for a better risk management, and provides more individual information for the patient. These are the most important aspects of this technology, which may contribute to establish higher-quality standards in

  18. Viscous tilting and production of vorticity in homogeneous turbulence

    Science.gov (United States)

    Holzner, M.; Guala, M.; Lüthi, B.; Liberzon, A.; Nikitin, N.; Kinzelbach, W.; Tsinober, A.

    2010-06-01

    Viscous depletion of vorticity is an essential and well known property of turbulent flows, balancing, in the mean, the net vorticity production associated with the vortex stretching mechanism. In this letter, we, however, demonstrate that viscous effects are not restricted to a mere destruction process, but play a more complex role in vorticity dynamics that is as important as vortex stretching. Based on the results from three dimensional particle tracking velocimetry experiments and direct numerical simulation of homogeneous and quasi-isotropic turbulence, we show that the viscous term in the vorticity equation can also locally induce production of vorticity and changes of the orientation of the vorticity vector (viscous tilting).

  19. Viscous tilting and production of vorticity in homogeneous turbulence

    CERN Document Server

    Holzner, M; Lüthi, B; Liberzon, A; Nikitin, N; Kinzelbach, W; Tsinober, A

    2010-01-01

    Viscous depletion of vorticity is an essential and well known property of turbulent flows, balancing, in the mean, the net vorticity production associated with the vortex stretching mechanism. In this letter we however demonstrate that viscous effects are not restricted to a mere destruction process, but play a more complex role in vorticity dynamics that is as important as vortex stretching. Based on results from particle tracking experiments (3D-PTV) and direct numerical simulation (DNS) of homogeneous and quasi isotropic turbulence, we show that the viscous term in the vorticity equation can also locally induce production of vorticity and changes of its orientation (viscous tilting).

  20. A computer simulation study of tilted smectic mesophases

    Energy Technology Data Exchange (ETDEWEB)

    Withers, I.M

    2000-05-01

    Results are presented from a series of simulations undertaken to determine the effect of a novel form of molecular biaxiality upon the phase behaviour of the well established Gay-Berne (GB) liquid crystal model. Firstly, the simulation of a bulk system interacting via the Internally-Rotated Gay Berne (IRGB) potential, which offers a single-site representation of a molecule rigidly constrained into a zig-zag conformation, is presented. The results of simulations performed for systems of IRGB particles with an aspect ratio of 3:1 confirm that the introduction of biaxiality into the model results in the destabilisation of the orientationally ordered phases. For particles with a sufficiently pronounced zig-zag conformation, this results in the complete destabilisation of the smectic A phase and the smectic B phase being replaced by the tilted smectic J phase. Following these observations, the effect upon the phase behaviour of increasing molecular elongation is also considered, with an increase in the aspect ratio from 3:1 to 4:1 resulting in the nematic and smectic J phases being replaced by smectic A and smectic G phases respectively. Secondly, a version of the IRGB potential modified to include a degree of molecular flexibility is considered. Results obtained from bulk systems interacting via the flexible IRGB for 3:1 and 4:1 molecules show that the introduction of flexibility results in the destabilisation of the smectic A phase and the stabilisation of the nematic and tilted hexatic phases. Finally, the effect upon the phase behaviour of the rigid IRGB model of the inclusion of a longitudinal linear quadrupole is examined. These results show that increasing quadrupole moment results in the destabilisation of the tilted hexatic phase, although the biaxial order parameter is increased with increasing quadrupole moment. There is no clear correlation between quadrupole magnitude and the other observed phase transitions, with the nematic and smectic A phases being

  1. Tilt table testing in patients with suspected epilepsy1

    DEFF Research Database (Denmark)

    Edfors, R.; Erdal, J.; Rogvi-Hansen, B.

    2008-01-01

    BACKGROUND: Approximately 20-30% of patients with epilepsy are misdiagnosed and syncope often seems to be the mistaken cause. We re-evaluated patients referred to an epilepsy clinic where suspicion of neurally mediated (reflex) syncope were raised using tilt table testing (HUT). METHODS: HUT...... laboratory results and medical records of 120 consecutive patients were reviewed retrospectively over a period of 27 months. RESULTS: HUT was positive in 59 (49%) patients. Seventeen of 38 (45%) patients previously diagnosed with epilepsy and taking antiepileptic drugs were found to be misdiagnosed. Four...

  2. Tilted versus axially placed dental implants: a meta-analysis.

    Science.gov (United States)

    Chrcanovic, Bruno Ramos; Albrektsson, Tomas; Wennerberg, Ann

    2015-02-01

    The purpose of the present review was to test the null hypothesis of no difference in the implant failure rate, marginal bone loss, and postoperative infection for patients being rehabilitated by tilted or by axially placed dental implants, against the alternative hypothesis of a difference. An electronic search without time or language restrictions was undertaken in July 2014. Eligibility criteria included clinical human studies, either randomised or not, interventional or observational. The estimates of an intervention were expressed in risk ratio (RR) and mean difference (MD) in millimetres. The search strategy resulted in 44 publications. A total of 5029 dental implants were tilted (82 failures; 1.63%), and 5732 implants were axially placed (104 failures; 1.81%). The difference between the procedures did not significantly affect the implant failure rates (P=0.40), with a RR of 1.14 (95% CI 0.84-1.56). A statistically significant difference was found for implant failures when studies evaluating implants inserted in maxillae only were pooled (RR 1.70, 95% CI 1.05-2.74; P=0.03), the same not happening for the mandible (RR 0.77, 95% CI 0.39-1.52; P=0.45). There were no apparent significant effects of tilted dental implants on the occurrence of marginal bone loss (MD 0.03, 95% CI -0.03 to 0.08; P=0.32). Due to lack of satisfactory information, meta-analysis for the outcome 'postoperative infection' was not performed. It is suggested that the differences in angulation of dental implants might not affect the implant survival or the marginal bone loss. The reliability and validity of the data collected and the potential for biases and confounding factors are some of the shortcomings of the present study. The question whether tilted implants are more at risk for failure than axially placed implants has received increasing attention in the last years. As the philosophies of treatment alter over time, a periodic review of the different concepts is necessary to refine

  3. Measuring the Virgo area tilt noise with a laser gyroscope

    CERN Document Server

    Belfi, Jacopo; Bosi, Filippo; Carelli, Giorgio; Di Virgilio, Angela; Maccioni, Enrico; Stefani, Fabio

    2011-01-01

    We report on the measurements of tilt noise performed at the Virgo site with a ring laser gyroscope. The apparatus is a He-Ne laser operating in a square cavity mounted on a vertical plane perpendicular to the north-south arm of the inteferometer. We discuss the possibility of using the ring laser signal to improve the performances of the control system of the Virgo seismic suspensions. The comparison between the ring laser signal and the control signals for the longitudinal translations of the inverted pendulum (IP) shows remarkable coherence in the frequency range 20-200 mHz.

  4. The impact of gravity during head-up tilt

    DEFF Research Database (Denmark)

    Ottesen, Johnny T.; Olufsen, Mette; Smith, Brittany

    The impact of gravity during head-up tilt, a test often used in the clinic to diagnose patients who suffer from dizziness or frequent episodes of syncope, is not well described. This study uses mathematical modeling to analyze experimental blood pressure data measured at the level of the aorta...... a model predicting hydrostatic height between the two locations. Results from this model were compared with measurements. Furthermore, we show, using a differential equations model predicting blood pressure, that it is possible to predict blood pressure measured at the level of the carotid sinuses using...

  5. The impact of gravity during head-up tilt

    DEFF Research Database (Denmark)

    Ottesen, Johnny T.; Olufsen, Mette; Smith, Brittany

    and the carotid sinuses in a healthy volunteer. During head-up tilt the head is lifted above the heart stimulating gravitational pooling of blood in the lower extremities. This shift in volume is followed by an increase in blood pressure in the lower body, while the pressure in the head decreases, while...... a model predicting hydrostatic height between the two locations. Results from this model were compared with measurements. Furthermore, we show, using a differential equations model predicting blood pressure, that it is possible to predict blood pressure measured at the level of the carotid sinuses using...

  6. Tilted bending magnet for SPS target area TCC2

    CERN Multimedia

    1976-01-01

    A slow-extracted proton beam from the SPS goes to the underground target zone TCC2. The part of the primary beam which traverses target T4 is recuperated and transported over some 800 m, for further use in the North Area High Intensity facility (NAHIF). The curved and sloped trajectory required 4 of the bending magnets to be tilted. Here we see one of them being attended by Gilbert Françon in hall 867, ready for installation in TCC2.

  7. Phosphorylated DegU Manipulates Cell Fate Differentiation in the Bacillus subtilis Biofilm

    Science.gov (United States)

    Marlow, Victoria L.; Porter, Michael; Hobley, Laura; Kiley, Taryn B.; Swedlow, Jason R.; Davidson, Fordyce A.

    2014-01-01

    Cell differentiation is ubiquitous and facilitates division of labor and development. Bacteria are capable of multicellular behaviors that benefit the bacterial community as a whole. A striking example of bacterial differentiation occurs throughout the formation of a biofilm. During Bacillus subtilis biofilm formation, a subpopulation of cells differentiates into a specialized population that synthesizes the exopolysaccharide and the TasA amyloid components of the extracellular matrix. The differentiation process is indirectly controlled by the transcription factor Spo0A that facilitates transcription of the eps and tapA (tasA) operons. DegU is a transcription factor involved in regulating biofilm formation. Here, using a combination of genetics and live single-cell cytological techniques, we define the mechanism of biofilm inhibition at high levels of phosphorylated DegU (DegU∼P) by showing that transcription from the eps and tapA promoter regions is inhibited. Data demonstrating that this is not a direct regulatory event are presented. We demonstrate that DegU∼P controls the frequency with which cells activate transcription from the operons needed for matrix biosynthesis in favor of an off state. Subsequent experimental analysis led us to conclude that DegU∼P functions to increase the level of Spo0A∼P, driving cell fate differentiation toward the terminal developmental process of sporulation. PMID:24123822

  8. The Structure of Dark Molecular Gas in the Galaxy - I: A Pilot Survey for 18-cm OH Emission Towards $l \\approx 105^{\\deg}, b \\approx +1^{\\deg}$

    CERN Document Server

    Allen, Ronald J; Engelke, Philip D

    2015-01-01

    We report the first results from a survey for 1665, 1667, and 1720 MHz OH emission over a small region of the Outer Galaxy centered at $l \\approx 105.0\\deg , b \\approx +1.0\\deg$ . This sparse, high-sensitivity survey ($\\Delta Ta \\approx \\Delta Tmb \\approx 3.0 - 3.5$ mK rms in 0.55 km/s channels), was carried out as a pilot project with the Green Bank Telescope (GBT, FWHM $\\approx 7.6'$) on a 3 X 9 grid at $0.5\\deg$ spacing. The pointings chosen correspond with those of the existing $^{12}$CO(1-0) CfA survey of the Galaxy (FWHM $\\approx 8.4'$). With 2-hr integrations, 1667 MHz OH emission was detected with the GBT at $\\gtrsim 21$ of the 27 survey positions ($\\geq 78\\%$ ), confirming the ubiquity of molecular gas in the ISM as traced by this spectral line. With few exceptions, the main OH lines at 1665 and 1667 MHz appear in the ratio of 5:9 characteristic of LTE at our sensitivity levels. No OH absorption features are recorded in the area of the present survey, in agreement with the low levels of continuum bac...

  9. Analysis of the thin layer of Galactic warm ionized gas in the range 20 < l < 30 deg, -1.5 < b < +1.5 deg

    CERN Document Server

    Paladini, R; Davies, R D; Giard, M

    2005-01-01

    We present an analysis of the thin layer of Galactic warm ionized gas at an angular resolution ~ 10'. This is carried out using radio continuum data at 1.4 GHz, 2.7 GHz and 5 GHz in the coordinate region 20 < l < 30 deg, -1.5 < b < +1.5 deg. For this purpose, we evaluate the zero level of the 2.7 and 5 GHz surveys using auxiliary data at 2.3 GHz and 408 MHz. The derived zero level corrections are T_{zero}(2.7 GHz)=0.15 +/- 0.06 K and T_{zero}(5 GHz)=0.1 +/- 0.05 K. We separate the thermal (free-free) and non-thermal (synchrotron) component by means of a spectral analysis performed adopting an antenna temperature spectral index -2.1 for the free-free emission, a realistic spatial distribution of indices for the synchrotron radiation and by fitting, pixel-by-pixel, the Galactic spectral index. We find that at 5 GHz, for |b| = 0 deg, the fraction of thermal emission reaches a maximum value of 82%, while at 1.4 GHz, the corresponding value is 68%. In addition, for the thermal emission, the analysis in...

  10. SAS-2 observations of the diffuse gamma radiation in the galactic latitude interval 10 deg absolute b or equal to 90 deg

    Science.gov (United States)

    Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.; Thompson, D. J.; Oegelman, H. B.; Oezel, M. E.; Tuemer, T.

    1977-01-01

    An analysis of all of the second small astronomy satellite gamma-ray data for galactic latitudes with the absolute value of b 10 deg has shown that the intensity varies with galactic latitude, being larger near 10 deg than 90 deg. For energies above 100 MeV the gamma-ray data are consistent with a latitude distribution of the form I(b) = C sub 1 + C sub 2/sin b, with the second term being dominant. This result suggests that the radiation above 100 MeV is coming largely from local regions of the galactic disk. Between 35 and 100 MeV, a similar equation is also a good representation of the data, but here the two terms are comparable. These results indicate that the diffuse radiation above 35 MeV consists of two parts, one with a relatively hard galactic component and the other an isotropic, steep spectral component which extrapolates back well to the low energy diffuse radiation. The steepness of the diffuse isotropic component places significant constraints on possible theoretical models of this radiation.

  11. Interhemispheric Comparison of Dipole Tilt Angle Effects on Latitude of Mid-Altitude Cusp

    Institute of Scientific and Technical Information of China (English)

    GUO Jian-Guang; SHI Jian-Kui; ZHANG Tie-Long; LIU Zhen-Xing

    2008-01-01

    A statistical study of interhemispheric comparison of dipole tilt angle effect on the latitude of the mid-altitude cusp is preformed by a data set of the Cluster cusp crossings over a 5-year period.The result shows that the dipole tilt angle has a clear control of the cusp latitudinal location.When the dipole tilts sunwards,the cusp is shifted poleward.The northern cusp moves 1° ILAT for every 15.4° increase in the dipole tilt angle,while the southern cusp moves 1° ILAT for every 20.8° increase in the dipole tilt angle. This suggests that an interhemispheric difference appears in the dependence of cusp latitudinal location on the dipole tilt angle.

  12. Modulated Electron Bunch with Amplitude Front Tilt in an Undulator

    CERN Document Server

    Geloni, Gianluca; Saldin, Evgeni

    2015-01-01

    In a previous paper we discussed the physics of a microbunched electron beam kicked by the dipole field of a corrector magnet by describing the kinematics of coherent undulator radiation after the kick. We demonstrated that the effect of aberration of light supplies the basis for understanding phenomena like the deflection of coherent undulator radiation by a dipole magnet. We illustrated this fact by examining the operation of an XFEL under the steady state assumption, that is a harmonic time dependence. We argued that in this particular case the microbunch front tilt has no objective meaning; in other words, there is no experiment that can discriminate whether an electron beam is endowed with a microbunch front tilt of not. In this paper we extend our considerations to time-dependent phenomena related with a finite electron bunch duration, or SASE mode of operation. We focus our attention on the spatiotemporal distortions of an X-ray pulse. Spatiotemporal coupling arises naturally in coherent undulator radi...

  13. Evaluation of Anterior Segment's Structures in Tilted Disc Syndrome

    Science.gov (United States)

    Ozsoy, Ercan; Demirel, Ersin Ersan; Cumurcu, Tongabay

    2016-01-01

    Purpose. To evaluate anterior segment's structures by Pentacam in patients with tilted disc syndrome (TDS). Methods. Group 1 included forty-six eyes of forty-six patients who have the TDS. Group 2 including forty-six eyes of forty-six cases was the control group which was equal to the study group in age, gender, and refraction. A complete ophthalmic examination was performed in both groups. All cases were evaluated by Pentacam. The axial length (AL) of eyes was measured by ultrasound. Quantitative data obtained from these measurements were compared between two groups. Results. There was no statistically significant difference for age, gender, axial length, and spherical equivalent measurements between two groups (p = 0.625, p = 0.830, p = 0.234, and p = 0.850). There was a statistically significant difference for central corneal thickness (CCT), corneal volume (CV), anterior chamber angle (ACA), and pupil size measurements between two groups (p = 0.001, p = 0.0001, p = 0.003, and p = 0.001). Also, there was no statistically significant difference for anterior chamber depth (ACD), anterior chamber volume (ACV), and lens thickness (LT) measurements between two groups (p = 0.130, p = 0.910, and p = 0.057). Conclusion. We determined that CCT was thinner, CV was less, and ACA was narrower in patients with TDS. There are some changes in the anterior segment of the eyes with tilted disc. PMID:27648303

  14. Seismometer Detection of Dust Devil Vortices by Ground Tilt

    CERN Document Server

    Lorenz, Ralph D; Murdoch, Naomi; Lognonné, Philippe; Kawamura, Taichi; Mimoun, David; Banerdt, W Bruce

    2015-01-01

    We report seismic signals on a desert playa caused by convective vortices and dust devils. The long-period (10-100s) signatures, with tilts of ~10$^{-7}$ radians, are correlated with the presence of vortices, detected with nearby sensors as sharp temporary pressure drops (0.2-1 mbar) and solar obscuration by dust. We show that the shape and amplitude of the signals, manifesting primarily as horizontal accelerations, can be modeled approximately with a simple quasi-static point-load model of the negative pressure field associated with the vortices acting on the ground as an elastic half space. We suggest the load imposed by a dust devil of diameter D and core pressure {\\Delta}Po is ~({\\pi}/2){\\Delta}PoD$^2$, or for a typical terrestrial devil of 5 m diameter and 2 mbar, about the weight of a small car. The tilt depends on the inverse square of distance, and on the elastic properties of the ground, and the large signals we observe are in part due to the relatively soft playa sediment and the shallow installatio...

  15. Characterizing local variability in long‐period horizontal tilt noise

    Science.gov (United States)

    Rohde, M.D.; Ringler, Adam; Hutt, Charles R.; Wilson, David; Holland, Austin; Sandoval, L.D; Storm, Tyler

    2017-01-01

    Horizontal seismic data are dominated by atmospherically induced tilt noise at long periods (i.e., 30 s and greater). Tilt noise limits our ability to use horizontal data for sensitive seismological studies such as observing free earth modes. To better understand the local spatial variability of long‐period horizontal noise, we observe horizontal noise during quiet time periods in the Albuquerque Seismological Laboratory (ASL) underground vault using four small‐aperture array configurations. Each array comprises eight Streckeisen STS‐2 broadband seismometers. We analyze the spectral content of the data using power spectral density and magnitude‐squared coherence (γ2‐coherence). Our results show a high degree of spatial variability and frequency dependence in the long‐period horizontal wavefield. The variable nature of long‐period horizontal noise in the ASL vault suggests that it might be highly local in nature and not easily characterized by simple physical models when overall noise levels are low, making it difficult to identify locations in the vault with lower horizontal noise. This variability could be limiting our ability to apply coherence analysis for estimating horizontal sensor self‐noise and could also complicate various indirect methods for removing long‐period horizontal noise (e.g., collocated rotational sensor or microbarograph).

  16. Fourier optics analysis of grating sensors with tilt errors.

    Science.gov (United States)

    Ferhanoglu, Onur; Toy, M Fatih; Urey, Hakan

    2011-06-15

    Dynamic diffraction gratings can be microfabricated with precision and offer extremely sensitive displacement measurements and light intensity modulation. The effect of pure translation of the moving part of the grating on diffracted order intensities is well known. This study focuses on the parameters that limit the intensity and the contrast of the interference. The effects of grating duty cycle, mirror reflectivities, sensor tilt and detector size are investigated using Fourier optics theory and Gaussian beam optics. Analytical findings reveal that fringe visibility becomes <0.3 when the optical path variation exceeds half the wavelength within the grating interferometer. The fringe visibility can be compensated by monitoring the interfering portion of the diffracted order light only through detector size reduction in the expense of optical power. Experiments were conducted with a grating interferometer that resulted in an eightfold increase in fringe visibility with reduced detector size, which is in agreement with theory. Findings show that diffraction grating readout principle is not limited to translating sensors but also can be used for sensors with tilt or other deflection modes.

  17. On the tilting of protostellar disks by resonant tidal effects

    CERN Document Server

    Lubow, S H

    2000-01-01

    We consider the dynamics of a protostellar disk surrounding a star in acircular-orbit binary system. Our aim is to determine whether, if the disk isinitially tilted with respect to the plane of the binary orbit, the inclinationof the system will increase or decrease with time. The problem is formulated inthe binary frame in which the tidal potential of the companion star is static.We consider a steady, flat disk that is aligned with the binary plane andinvestigate its linear stability with respect to tilting or warpingperturbations. The dynamics is controlled by the competing effects of the m=0and m=2 azimuthal Fourier components of the tidal potential. In the presence ofdissipation, the m=0 component causes alignment of the system, while the m=2component has the opposite tendency. We find that disks that are sufficientlylarge, in particular those that extend to their tidal truncation radii, aregenerally stable and will therefore tend to alignment with the binary plane ona time-scale comparable to that found ...

  18. Effective ellipsoidal models for wavefield extrapolation in tilted orthorhombic media

    KAUST Repository

    Waheed, Umair Bin

    2016-04-22

    Wavefield computations using the ellipsoidally anisotropic extrapolation operator offer significant cost reduction compared to that for the orthorhombic case, especially when the symmetry planes are tilted and/or rotated. However, ellipsoidal anisotropy does not provide accurate wavefield representation or imaging for media of orthorhombic symmetry. Therefore, we propose the use of ‘effective ellipsoidally anisotropic’ models that correctly capture the kinematic behaviour of wavefields for tilted orthorhombic (TOR) media. We compute effective velocities for the ellipsoidally anisotropic medium using kinematic high-frequency representation of the TOR wavefield, obtained by solving the TOR eikonal equation. The effective model allows us to use the cheaper ellipsoidally anisotropic wave extrapolation operators. Although the effective models are obtained by kinematic matching using high-frequency asymptotic, the resulting wavefield contains most of the critical wavefield components, including frequency dependency and caustics, if present, with reasonable accuracy. The proposed methodology offers a much better cost versus accuracy trade-off for wavefield computations in TOR media, particularly for media of low to moderate anisotropic strength. Furthermore, the computed wavefield solution is free from shear-wave artefacts as opposed to the conventional finite-difference based TOR wave extrapolation scheme. We demonstrate applicability and usefulness of our formulation through numerical tests on synthetic TOR models. © 2016 Institute of Geophysics of the ASCR, v.v.i

  19. An efficient wave extrapolation method for anisotropic media with tilt

    KAUST Repository

    Waheed, Umair bin

    2015-03-23

    Wavefield extrapolation operators for elliptically anisotropic media offer significant cost reduction compared with that for the transversely isotropic case, particularly when the axis of symmetry exhibits tilt (from the vertical). However, elliptical anisotropy does not provide accurate wavefield representation or imaging for transversely isotropic media. Therefore, we propose effective elliptically anisotropic models that correctly capture the kinematic behaviour of wavefields for transversely isotropic media. Specifically, we compute source-dependent effective velocities for the elliptic medium using kinematic high-frequency representation of the transversely isotropic wavefield. The effective model allows us to use cheaper elliptic wave extrapolation operators. Despite the fact that the effective models are obtained by matching kinematics using high-frequency asymptotic, the resulting wavefield contains most of the critical wavefield components, including frequency dependency and caustics, if present, with reasonable accuracy. The methodology developed here offers a much better cost versus accuracy trade-off for wavefield computations in transversely isotropic media, particularly for media of low to moderate complexity. In addition, the wavefield solution is free from shear-wave artefacts as opposed to the conventional finite-difference-based transversely isotropic wave extrapolation scheme. We demonstrate these assertions through numerical tests on synthetic tilted transversely isotropic models.

  20. On the dynamics of tilted black hole-torus systems

    CERN Document Server

    Mewes, Vassilios; Font, José A; Montero, Pedro J; Stergioulas, Nikolaos

    2016-01-01

    We present results from three-dimensional, numerical relativity simulations of a tilted black hole-thick accretion disc system. The simulations are analysed using tracer particles in the disc which are advected with the flow. Such tracers, which we employ in these new simulations for the first time, provide a powerful means to analyse in detail the complex dynamics of tilted black hole-torus systems. We show how its use helps to gain insight in the overall dynamics of the system, discussing the origin of the observed black hole precession and the development of a global non-axisymmetric $m=1$ mode in the disc. Our three-dimensional simulations show the presence of quasi-periodic oscillations (QPOs) in the instantaneous accretion rate, with frequencies in a range compatible with those observed in low mass X-ray binaries with either a black hole or a neutron star component. The frequency ratio of the dominant low frequency peak and the first overtone is $o_1/f \\sim 1.9$, a frequency ratio not attainable when mo...

  1. A tilted interference filter in a converging beam

    CERN Document Server

    Löfdahl, Mats G; Kiselman, Dan

    2011-01-01

    Context. Narrow-band interference filters can be tuned toward shorter wavelengths by tilting them from the perpendicular to the optical axis. This can be used as a cheap alternative to real tunable filters, such as Fabry-P\\'erot interferometers and Lyot filters. At the Swedish 1-m Solar Telescope, such a setup is used to scan through the blue wing of the Ca II H line. Because the filter is mounted in a converging beam, the incident angle varies over the pupil, which causes a variation of the transmission over the pupil, different for each wavelength within the passband. This causes broadening of the filter transmission profile and degradation of the image quality. Aims. We want to characterize the properties of our filter, at normal incidence as well as at different tilt angles. Knowing the broadened profile is important for the interpretation of the solar images. Compensating the images for the degrading effects will improve the resolution and remove one source of image contrast degradation. In particular, w...

  2. Dynamic UCLA for single tilted implant in an aesthetic region.

    Science.gov (United States)

    Goiato, Marcelo Coelho; Sônego, Mariana Vilela; da Silva, Emily Vivianne Freitas; de Carvalho Dekon, Stefan Fiuza; de Medeiros, Rodrigo Antonio; Carvalho, Karina Helga Turcio de; Dos Santos, Daniela Micheline

    2015-01-01

    The aim of this paper was to present a rehabilitation of a patient with a dynamic universal castable long abutment (UCLA) for a single tilted implant in the anterior maxillary area. A 57-year-old male patient attended the dentistry college clinic complaining of a vertical fracture of a residual root of the dental element 22. The tooth extraction was indicated for the implant installation. Due to the socket buccal wall thickness, the implant was installed with an inclination to the palate. It was done in a two-stage surgical protocol, and an external hexagon implant (3.75×11.5mm) was placed. After a six-month healing period to correct the implant position, a dynamic UCLA was set in place, rectifying the implant emergence profile at 20°. The ceramic structure fitting was performed and, after the patient's consent, the prosthesis was finalized and installed. After a follow-up period of twenty months, no complications were observed. The installation of tilted implants with a dynamic UCLA may be a viable option, faster and less invasive than bone grafts. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Spontaneous tilting after placement of the gunther-tulip inferior vena caval filter: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Tae Seok; Cha, In Ho; Seol, Hae Young; Park, Cheol Min [Guro Hospital, Korea University College of Medicine, Seoul (Korea, Republic of)

    2006-10-15

    Tilting of a deployed filter in the inferior vena cava (IVC) is a particular kind of periprocedural complication and this can reduce the filter's clot-trapping ability and increase the occlusion of the IVC at a later period. The authors report here on a case of spontaneous tilting of an inferior vena caval filter that was associated with thrombosis in the IVC within 2 weeks of the initially successful placement of the filter without tilting.

  4. Effects of Head-down Bed Rest Stimulated Weightlessness on Perceptual Accuracy and Conflict Control Function%头低位卧床模拟失重对知觉正确性和冲突控制能力的影响

    Institute of Scientific and Technical Information of China (English)

    程真波; 李冬冬; 谈诚; 杜博琪; 罗跃嘉; 陈文娟; 陈晓萍; 白延强; 黄宇霞

    2013-01-01

    目的 探究45 d-6°头低位卧床中知觉正确性和冲突控制能力受到的影响和变化规律.方法 采用头低位卧床模拟失重,选取视觉后向掩蔽任务和刺激-反应冲突任务,在卧床实验6个不同阶段(卧床前第6天,卧床中第11,20,30和40天,以及卧床后第8天)对16名志愿者进行重复测试.结果 在知觉正确性测试中,志愿者在卧床第11天的正确率显著提高(P>0.05),在卧床第32天时达到并维持在一个较高的水平直至卧床后第8天最后一次测试.在刺激-反应冲突任务中,在卧床第32天测试中出现显著的促进作用(P>0.05),并在起床后明显下降.结论 头低位卧床对认知功能不会造成明显损害,甚至可能有促进作用;知觉正确性和反应协调性的变化趋势在卧床早期具有一定的相似性;在卧床结束后冲突控制能力降低,但知觉正确性未受影响.%Objective To investigate the influence of 45 d of-6° head-down bed rest ( HDBR) on perceptual accuracy and conflict control function. Methods Sixteen healthy subjects participated in this experiment. Six test sessions were conducted; on the 6th day before bed rest, on the 11th, 20th, 32nd and 40th day of bed rest and on the 8 th day of recovery after HDBR. The visual backward masking task and the stimulus-response conflict task were adopted to test the subjects' perceptual accuracy and conflict control function separately. Results In the visual backward masking task, the accuray on the 11 th day of HDBR was increased significantly as compared with that in pre-HDBR(P >0. 05). And the performance was reached to a higher level on the 32nd day of HDBR, following a period of performance stabilization until post-HDBR. In the stimulus-response conflict task, there was a significant improvement on the 32nd day of HDBR( P > 0. 05). But the performance was damaged apparently in post-HDBR. Conclusion Simulated weightlessness is of no significant negative influence on

  5. Effects of 30 d-6°Head-down Bed Rest on Lumbar Spine and Lumbar Paraspinal Muscles%30d-6°头低位卧床对腰椎和椎旁肌肉面积的影响

    Institute of Scientific and Technical Information of China (English)

    冯金升; 李勇枝; 郭立国; 石宏志; 李奕兴; 金真; 王健

    2011-01-01

    Objective To study the changes of entire lumbar spinal height,the lordotic angle,the midsagittal area between adjacent lumbar vertebral bodies and the cross-sectional area of lumbar paraspinal muscles following 30 d-6°head-down bed rest (HDBR.Methods A 30 d-6°HDBR experiment was proposed to simulate weightlessness effects.Fourteen healthy male subjects volunteered to participate in the experiment.All subjects underwent magnetic resonance imaging (MRI)test in supine psoas-relaxed position before and after HDBR.Midsagittal views were used to measure the entire lumbar spinal height,the midsagittal area between adjacent lumbar vertebral bodies and lordotic angle.Axial MR image at the level of the L4-L5 disc was used to determine cross-sectional area of lumbar paraspinal muscles.Results After 30 d-6°HDBR,the entire lumbar spinal height of subjects was higher and the midsagittal areas of subjects were larger than those measured before HDBR (P < 0.01).The cross-sectional area of lumbar paraspinal muscles reduced significantly (P < 0.01).The lordotic angle of subjects did not change significantly.Conclusion Thirty days of HDBR at-6°can affect lumbar spinal stability and function and then result in the changes in lumbar spinal biomechanics.%目的 观察30 d-6°头低位卧床实验后志愿者腰椎高度、腰椎间隙中矢状位面积、腰椎前凸角度以及椎旁肌肉横切面积的变化.方法 14名健康男性参加30 d卧床模拟失重实验.于卧床前1天、卧床第30天分别进行腰椎核磁检测,同时测量人体腰椎高度、腰椎间隙中矢状位面积、腰椎前凸角度以及椎旁肌肉横切面积.结果 30 d卧床实验后志愿者腰椎高度增加(P<0.01)、腰椎间隙中矢状位面积增大(P<0.01),椎旁肌肉横切面积减少(P<0.01),而腰椎前凸角度变化不明显.结论 30 d-6°头低位卧床模拟失重对人体腰椎稳定性和功能有影响,从而导致人体腰椎的生物力学变化.

  6. Fairness and the EC budget: Is Spain tilting at windmills?

    OpenAIRE

    Bowles, Roger; Jones, Philip

    1991-01-01

    The poorer member states of the EC are often disappointed at what they see as a very limited degree of redistribution of resources away from the richer members towards the less well off. In a recent paper to the intergovernmental conference (IGC) on political union, for example, Spain calls for a number of measures, including explicit inter-state budget transfers, in order to increase the rate of convergence of income levels across member states. The purpose of this paper is to review the deg...

  7. Electrical spin injection and detection in high mobility 2DEG systems

    Science.gov (United States)

    Ciorga, M.

    2016-11-01

    In this review paper we present the current status of research related to the topic of electrical spin injection and detection in two-dimensional electron gas (2DEG) systems, formed typically at the interface between two III-V semiconductor compounds. We discuss both theoretical aspects of spin injection in case of ballistic transport as well as give an overview of available reports on spin injection experiments performed on 2DEG structures. In the experimental part we focus particularly on our recent work on all-semiconductor structures with a 2DEG confined at an inverted GaAs/(Al,Ga)As interface and with a ferromagnetic semiconductor (Ga,Mn)As employed as a source of spin-polarized electrons.

  8. Ten deg off-axis tensile test for intralaminar shear characterization of fiber composites

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1976-01-01

    A combined theoretical and experimental investigation was conducted to assess the suitability of the 10 deg off-axis tensile test specimen for the intralaminar shear characterization of unidirectional composites. Composite mechanics, a combined-stress failure criterion, and a finite element analysis were used to determine theoretically the stress-strain variation across the specimen width and the relative stress and strain magnitudes at the 10 deg plane. Strain gages were used to measure the strain variation across the specimen width at specimen midlength and near the end tabs. Specimens from Mod-I/epoxy, T-300/epoxy, and S-glass/epoxy were used in the experimental program. It was found that the 10 deg off-axis tensile test specimen is suitable for intralaminar shear characterization and it is recommended that it should be considered as a possible standard test specimen for such a characterization.

  9. Giovanni Degli Alessandri: i primi anni del direttorato agli Uffizi fra nuovi e vecchi ruoli

    Directory of Open Access Journals (Sweden)

    Chiara Pasquinelli

    2011-11-01

    Full Text Available La figura di Giovanni Degli Alessandri (1765-1830, presidente dell’Accademia di Belle Arti di Firenze e direttore degli Uffizi tra gli anni napoleonici e la Restaurazione di Ferdinando III d’Asburgo-Lorena, è quella di un personaggio chiave nella politica artistica fiorentina, e toscana più in generale. Nel saggio si esaminano i primi anni del suo direttorato alla Galleria, i rapporti con Antonio Canova, il suo ruolo all’interno dell’entourage di Elisa Baciocchi Bonaparte, oltre a considerare alcuni spunti legati al rinnovamento degli Uffizi, nonché la delicata vicenda del passaggio in città di Dominique-Vivant Denon, direttore del Louvre. L’obbiettivo è quello di introdurre elementi di approfondimento relativamente a una figura molto nota ma poco studiata.

  10. A high sensitivity HI survey of the sky at delta < -25 deg Final data release

    CERN Document Server

    Bajaja, E; Larrarte, J J; Morras, R; Poppel, W G L; Kalberla, P M W

    2005-01-01

    We present the final data release of the high sensitivity lambda 21-cm neutral hydrogen survey of the sky south of delta < -25 degr. A total of 50980 positions lying on a galactic coordinate grid with points spaced by (Delta l, Delta b) = ((0.5 deg)/cos b, 0.5 deg) were observed with the 30-m dish of the Instituto Argentino de Radioastronomia (IAR). The angular resolution of the survey is HPBW = 0.5 deg and the velocity coverage spans the interval -450 km/s to +400 km/s (LSR). The velocity resolution is 1.27 km/s and the final rms noise of the entire database is 0.07 K. The data are corrected for stray radiation and converted to brightness temperatures.

  11. Measurement of the Floor Tilt in Experimental Determination of the Gravitational Constant

    Institute of Scientific and Technical Information of China (English)

    吴书朝; 黄玉; 范淑华; 罗俊

    2003-01-01

    A prototype of a device with an impact structure for measuring the floor tilt has been built in our laboratory.The mechanical construction and the capacitive transducer of the device are introduced. Experimental results indicate that the floor tilt is about 16μrad in our cavity laboratory, and the uncertainty AG/G caused by such tilt is less than 0.54 parts per million (ppm), so the floor tilt can be reasonably neglected in the experimental determination of the gravitational constant G with the total uncertainty of about 10ppm.

  12. Solar Tilt Measurement of Array for Building Application and Error Analysis

    OpenAIRE

    Agarwal, Abhishek; Vashishtha, Vineet Kumar; S N Mishra

    2016-01-01

    Abstract The optimum angle show some variations when compared with values reported in the literature. The amount of solar radiation incident on a tilted module surface is the component of the incident solar radiation which is perpendicular to the module surface. The array’s tilt is the angle in degrees from horizontal. A flat roof has 0 degree tilt and a vertical wall mount has a 90 degrees tilt angle. Whether you are installing solar panel on a flat roof or a pitched roof, the output of the ...

  13. Phase shifting interferometry from two normalized interferograms with random tilt phase-shift.

    Science.gov (United States)

    Liu, Fengwei; Wu, Yongqian; Wu, Fan

    2015-07-27

    We propose a novel phase shifting interferometry from two normalized interferograms with random tilt phase-shift. The determination of tilt phase-shift is performed by extracting the tilted phase-shift plane from the phase difference of two normalized interferograms, and with the calculated tilt phase-shift value the phase distribution can be retrieved from the two normalized frames. By analyzing the distribution of phase difference and utilizing special points fitting method, the tilted phase-shift plane is extracted in three different cases, which relate to different magnitudes of tilts. Proposed method has been applied to simulations and experiments successfully and the satisfactory results manifest that proposed method is of high accuracy and high speed compared with the three step iterative method. Additionally, both open and closed fringe can be analyzed with proposed method. What's more, it cannot only eliminate the small tilt-shift error caused by slight vibration in phase-shifting interferometry, but also detect the large tilt phase-shift in phase-tilting interferometry. Thus, it will relaxes the requirements on the accuracy of phase shifter, and the costly phase shifter may even be useless by applying proposed method in high amplitude vibrated circumstance to achieve high-precision analysis.

  14. Reclutamento e formazione dei poliziotti: il caso degli ufficiali della gendarmeria francese

    Directory of Open Access Journals (Sweden)

    François Dieu

    2007-04-01

    Full Text Available Partendo dal caso degli ufficiali della gendarmeria francese, questo articolo illustra il modo in cui il reclutamento e la formazione possono contribuire, informalmente, alla ripartizione del potere nelle organizzazioni di polizia. Tramite la diversità delle vie di reclutamento si costituisce, di fatto, un vero e proprio sistema di "caste", con una stratificazione degli ufficiali in tre livelli gerarchici, che produce, al di là dei principi meritocratici, delle ineguaglianze manifeste nella ripartizione del potere nell'organizzazione della gendarmeria.

  15. The effects of gantry tilt on breast dose and image noise in cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, Michael E.; Gandhi, Diksha; Schmidt, Taly Gilat [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States); Stevens, Grant M. [GE Healthcare, Waukesha, Wisconsin 53188 (United States); Foley, W. Dennis [Department of Radiology, Medical College of Wisconsin, Froedtert Memorial Lutheran Hospital, Milwaukee, Wisconsin 53226 (United States)

    2013-12-15

    Purpose: This study investigated the effects of tilted-gantry acquisition on image noise and glandular breast dose in females during cardiac computed tomography (CT) scans. Reducing the dose to glandular breast tissue is important due to its high radiosensitivity and limited diagnostic significance in cardiac CT scans.Methods: Tilted-gantry acquisition was investigated through computer simulations and experimental measurements. Upon IRB approval, eight voxelized phantoms were constructed from previously acquired cardiac CT datasets. Monte Carlo simulations quantified the dose deposited in glandular breast tissue over a range of tilt angles. The effects of tilted-gantry acquisition on breast dose were measured on a clinical CT scanner (CT750HD, GE Healthcare) using an anthropomorphic phantom with MOSFET dosimeters in the breast regions. In both simulations and experiments, scans were performed at gantry tilt angles of 0°–30°, in 5° increments. The percent change in breast dose was calculated relative to the nontilted scan for all tilt angles. The percent change in noise standard deviation due to gantry tilt was calculated in all reconstructed simulated and experimental images.Results: Tilting the gantry reduced the breast dose in all simulated and experimental phantoms, with generally greater dose reduction at increased gantry tilts. For example, at 30° gantry tilt, the dosimeters located in the superior, middle, and inferior breast regions measured dose reductions of 74%, 61%, and 9%, respectively. The simulations estimated 0%–30% total breast dose reduction across the eight phantoms and range of tilt angles. However, tilted-gantry acquisition also increased the noise standard deviation in the simulated phantoms by 2%–50% due to increased pathlength through the iodine-filled heart. The experimental phantom, which did not contain iodine in the blood, demonstrated decreased breast dose and decreased noise at all gantry tilt angles.Conclusions: Tilting the

  16. QtUCP-A program for determining unit-cell parameters in electron diffraction experiments using double-tilt and rotation-tilt holders

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Hongsheng [Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011 (China); Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China)], E-mail: zhaohscas@yahoo.com.cn; Wu Deqi [Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011 (China); Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Yao Jincheng; Chang Aimin [Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)

    2008-11-15

    A computer program, QtUCP, has been developed based on several well-established algorithms using GCC 4.0 and Qt 4.0 (Open Source Edition) under Debian GNU/Linux 4.0r0. It can determine the unit-cell parameters from an electron diffraction tilt series obtained from both double-tilt and rotation-tilt holders. In this approach, two or more primitive cells of the reciprocal lattice are determined from experimental data, in the meantime, the measurement errors of the tilt angles are checked and minimized. Subsequently, the derived primitive cells are converted into the reduced form and then transformed into the reduced direct primitive cell. Finally all the patterns are indexed and the least-squares refinement is employed to obtain the optimized results of the lattice parameters. Finally, two examples are given to show the application of the program, one is based on the experiment, the other is from the simulation.

  17. QtUCP-a program for determining unit-cell parameters in electron diffraction experiments using double-tilt and rotation-tilt holders.

    Science.gov (United States)

    Zhao, Hongsheng; Wu, Deqi; Yao, Jincheng; Chang, Aimin

    2008-11-01

    A computer program, QtUCP, has been developed based on several well-established algorithms using GCC 4.0 and Qt 4.0 (Open Source Edition) under Debian GNU/Linux 4.0r0. It can determine the unit-cell parameters from an electron diffraction tilt series obtained from both double-tilt and rotation-tilt holders. In this approach, two or more primitive cells of the reciprocal lattice are determined from experimental data, in the meantime, the measurement errors of the tilt angles are checked and minimized. Subsequently, the derived primitive cells are converted into the reduced form and then transformed into the reduced direct primitive cell. Finally all the patterns are indexed and the least-squares refinement is employed to obtain the optimized results of the lattice parameters. Finally, two examples are given to show the application of the program, one is based on the experiment, the other is from the simulation.

  18. A tilted plane as a gravitational field model

    Science.gov (United States)

    Hale, D. P.

    1980-09-01

    Gravitational models have been widely used to study the effects of fields on particle motion. The advantages of such models are: (1) They are often easier or cheaper to construct and use than the system which they represent. (2) Particle motion is readily seen and may be photographed. (3) Events lasting for a fraction of a microsecond as, for example, with electrons moving in electrostatic fields, may be demonstrated in models as events which take a few seconds. The article describes the use of a tilted plane as a two-dimensional, uniform gravitational field. It has been used successfully as a sixth-form physics experiment to demonstrate the motion of projectiles fairly close to the Earth over a limited range. Thus it shows the motion of artillery shells (ignoring air resistance) but not of artificial satellites or long-range rockets, for which a simple uniform field model is not valid.

  19. Learning from history: Adaptive calibration of 'tilting spine' fiber positioners

    CERN Document Server

    Gilbert, James

    2015-01-01

    This paper discusses a new approach for determining the calibration parameters of independently-actuated optical fibers in multi-object astronomical fiber positioning systems. This work comes from the development of a new type of piezoelectric motor intended to enhance the 'tilting spine' fiber positioning technology originally created by the Australian Astronomical Observatory. Testing has shown that the motor's performance can vary depending on the fiber's location within its accessible field, meaning that an individual fiber is difficult calibrate with a one-time routine. Better performance has resulted from constantly updating calibration parameters based on the observed movements of the fiber during normal closed-loop positioning. Over time, location-specific historical data is amassed that can be used to better predict the results of a future fiber movement. This is similar to a technique previously proposed by the Australian Astronomical Observatory, but with the addition of location-specific learning....

  20. The Lyth Bound of Inflation with a Tilt

    CERN Document Server

    Garcia-Bellido, Juan; Scalisi, Marco; Zavala, Ivonne

    2014-01-01

    We provide strong evidence for universality of the inflationary field range: given an accurate measurement of $(n_s,r)$, one can infer $\\Delta \\phi$ in a model-independent way in the sub-Planckian regime for a range of universality classes of inflationary models. Both the tensor-to-scalar ratio as well as the spectral tilt are essential for the field range. Given the Planck constraints on $n_s$, the Lyth bound is strengthened by two orders of magnitude: whereas the original bound gives a sub-Planckian field range for $r \\lesssim 2 \\cdot 10^{-3}$, we find that $n=0.96$ brings this down to $r \\lesssim 2 \\cdot 10^{-5}$.

  1. Rain Sensor with Stacked Light Waveguide Having Tilted Air Gap

    Directory of Open Access Journals (Sweden)

    Kyoo Nam Choi

    2014-01-01

    Full Text Available Vehicle sensor to detect rain drop on and above waveguide utilizing light deflection and scattering was realized, keeping wide sensing coverage and sensitivity to detect mist accumulation. Proposed sensor structure under stacked light wave guide consisted of light blocking fixture surrounding photodetector and adjacent light source. Tilted air gap between stacked light waveguide and light blocking fixture played major role to increase sensitivity and to enhance linearity. This sensor structure eliminated complex collimating optics, while keeping wide sensing coverage using simple geometry. Detection algorithm based on time-to-intensity transformation process was used to convert raining intensity into countable raining process. Experimental result inside simulated rain chamber showed distinct different response between light rain and normal rain. Application as automobile rain sensor is expected.

  2. Bound Chains of Tilted Dipoles in Layered Systems

    DEFF Research Database (Denmark)

    G. Volosniev, A.; R. Armstrong, J.; V. Fedorov, D.;

    2012-01-01

    is fascinating. Here we concentrate on few-body states in a multilayered setup. We exploit the geometry of the interlayer potential to calculate the two- and three-body chains with one molecule in each layer. The focus is on dipoles that are aligned at some angle with respect to the layer planes by means...... of an external eletric field. The binding energy and the spatial structure of the bound states are studied in several different ways using analytical approaches. The results are compared to stochastic variational calculations and very good agreement is found. We conclude that approximations based on harmonic...... oscillator potentials are accurate even for tilted dipoles when the geometry of the potential landscape is taken into account....

  3. The Tilt between Acretion Disk and Stellar Disk

    Indian Academy of Sciences (India)

    Shiyin Shen; Zhengyi Shao; Minfeng Gu

    2011-03-01

    The orientations of the accretion disk of active galactic nuclei (AGN) and the stellar disk of its host galaxy are both determined by the angular momentum of their forming gas, but on very different physical environments and spatial scales. Here we show the evidence that the orientation of the stellar disk is correlated with the accretion disk by comparing the inclinations of the stellar disks of a large sample of Type 2 AGNs selected from Sloan Digital Sky Survey (SDSS, York et al. 2000) to a control galaxy sample. Given that the Type 2 AGN fraction is in the range of 70–90 percent for low luminosity AGNs as a priori, we find that the mean tilt between the accretion disk and stellar disk is ∼ 30 degrees (Shen et al. 2010).

  4. Flow tilt angles near forest edges - Part 2: Lidar anemometry

    DEFF Research Database (Denmark)

    Dellwik, Ebba; Mann, Jakob; Bingöl, Ferhat

    2010-01-01

    ) a fetch-limited beech forest site taken at 48–175 m a.g.l. (above ground level), (2) a reference site in flat agricultural terrain and (3) a second reference site in complex terrain are presented. The method to derive flow tilt angles and mean vertical velocities from lidar has several advantages compared...... vertical velocity, whereas the error due to flow inhomogeneity on the horizontal mean wind speed is independent of the lidar beam angle. For the presented measurements over forest, it is evaluated that the systematic error due to the inhomogeneity of the flow is less than 0.2°. The results of the vertical...... conical scans were promising, and yielded positive flow angles for a sector where the forest is fetch-limited. However, more data and analysis are needed for a complete evaluation of the lidar technique....

  5. Supramolecular tilt chirality in crystals of steroids and alkaloids.

    Science.gov (United States)

    Hisaki, Ichiro; Tohnai, Norimitsu; Miyata, Mikiji

    2008-03-01

    The concept of supramolecular chirality has assumed increasing importance in association with the development of supramolecular chemistry over the last two decades. In chiral crystals, 2 1 helical molecular assemblies are frequently observed as key motifs. Helical handedness of the 2 1 assemblies, however, has not been determined from the mathematical or crystallographical viewpoints. In this context, we have proposed two new concepts, three-axial chirality and tilt chirality. On the basis of the concepts, we describe supramolecular chirality and determine the handedness of 2 1 assemblies that are composed of relatively complicated molecules with multiple stereogenic centers such as brucine, bile acids, and cinchona alkaloids as well as those of simple molecules.

  6. Three-dimensional deconvolution microfluidic microscopy using a tilted channel

    Science.gov (United States)

    Pégard, Nicolas C.; Fleischer, Jason W.

    2013-04-01

    We have developed a microfluidic device that enables the computation of three-dimensional (3-D) images of flowing samples. Using a microfluidic channel that is tilted along the optical axis, we record several progressively defocused images of the flowing sample as it passes across the focal plane. The resulting focal stack is then deconvolved to generate 3-D images. Experimental results on flowing yeast cells reveal both volume and surface profile information. The microfluidic channel eliminates the need for a precise translation stage to control defocusing and enables high sample throughput in an insulated, nontoxic, liquid environment. The experimental device can be implemented in all existing microscopes as a modified slide stage and is ideally suited for 3-D profiling in flow cytometers.

  7. Degradation of PsbO by the Deg protease HhoA Is thioredoxin dependent.

    Directory of Open Access Journals (Sweden)

    Irma N Roberts

    Full Text Available The widely distributed members of the Deg/HtrA protease family play an important role in the proteolysis of misfolded and damaged proteins. Here we show that the Deg protease rHhoA is able to degrade PsbO, the extrinsic protein of the Photosystem II (PSII oxygen-evolving complex in Synechocystis sp. PCC 6803 and in spinach. PsbO is known to be stable in its oxidized form, but after reduction by thioredoxin it became a substrate for recombinant HhoA (rHhoA. rHhoA cleaved reduced eukaryotic (specifically, spinach PsbO at defined sites and created distinct PsbO fragments that were not further degraded. As for the corresponding prokaryotic substrate (reduced PsbO of Synechocystis sp. PCC 6803, no PsbO fragments were observed. Assembly to PSII protected PsbO from degradation. For Synechocystis sp. PCC 6803, our results show that HhoA, HhoB, and HtrA are localized in the periplasma and/or at the thylakoid membrane. In agreement with the idea that PsbO could be a physiological substrate for Deg proteases, part of the cellular fraction of the three Deg proteases of Synechocystis sp. PCC 6803 (HhoA, HhoB, and HtrA was detected in the PSII-enriched membrane fraction.

  8. The air oxidation behavior of lanthanum ion implanted zirconium at 500 deg. C

    CERN Document Server

    Peng, D Q; Chen, X W; Zhou, Q G

    2003-01-01

    The beneficial effect of lanthanum ion implantation on the oxidation behavior of zirconium at 500 deg. C has been studied. Zirconium specimens were implanted by lanthanum ions using a MEVVA source at energy of 40 keV with a fluence range from 1x10 sup 1 sup 6 to 1x10 sup 1 sup 7 ions/cm sup 2 at maximum temperature of 130 deg. C, The weight gain curves were measured after being oxidized in air at 500 deg. C for 100 min, which showed that a significant improvement was achieved in the oxidation behavior of zirconium ion implanted with lanthanum compared with that of the as-received zirconium. The valence of the oxides in the scale was analyzed by X-ray photoemission spectroscopy; and then the depth distributions of the elements in the surface of the samples were obtained by Auger electron spectroscopy. Glancing angle X-ray diffraction at 0.3 deg. incident angles was employed to examine the modification of its phase transformation because of the lanthanum ion implantation in the oxide films. It was obviously fou...

  9. A Byzantine chant collection from Sicily: a collaboration between Copenhagen and Piana degli Albanesi (Palermo)

    DEFF Research Database (Denmark)

    Sanfratello, Giuseppe

    2016-01-01

    The aim of this paper is to give an account of the collaboration between a collector of the Byzantine chant tradition of Piana degli Albanesi (Palermo) in Sicily, namely fr. Bartolomeo Di Salvo, and the editorial board of the Monumenta Musicae Byzantinae, i.e. an institution under the aegis......, Collections, Ethnomusicology, Critical edition, Monumenta Musicae Byzantinae (MMB)...

  10. Phosphorylation of DegU is essential for activation of amyE expression in Bacillus subtilis

    Indian Academy of Sciences (India)

    Monica Gupta; K Krishnamurthy Rao

    2014-12-01

    Alpha ()-amylase (amyE) is one of the major exo-enzymes secreted by Bacillus subtilis during the post-exponential phase. The DegS-DegU two-component system regulates expression of majority of post-exponentially expressed genes in B. subtilis. It has been demonstrated that varying levels of the phosphorylated form of DegU (DegU-P) control different cellular processes. Exo-protease production is observed when effective concentration of DegU-P rises in the cell, whereas swarming motility is favoured at very low amounts of DegU-P. In this study we show that like other exo-proteases, expression of amyE is positively regulated by increase in DegU-P levels in the cell. We also demonstrate that residues at the DNA-binding helix-turn-helix (HTH) motif of DegU are necessary for the amyE expression. This observation is further reinforced by demonstrating the direct interaction of DegU on amyE promoter.

  11. Optimum Tilt Angle for Photovoltaic Solar Panels in Zomba District, Malawi

    Directory of Open Access Journals (Sweden)

    B. Kamanga

    2014-01-01

    Full Text Available A study to determine the optimum tilt angle for installing photovoltaic solar panels in Zomba district, Malawi, has been conducted. The study determined the optimum monthly tilt angles of PV solar panels and the seasonal adjustments needed for the panels in order to collect maximum solar radiation throughout the year. In this study, global solar radiation (GSR on four tilted surfaces was measured. The north-facing surfaces were titled at angles of 0°, 15°, 20°, and 25°. The GSR data was used to determine the daily and monthly optimum tilt angles for the PV panels. The optimum tilt angles were found to be 0° or 25° depending on the time of the year. From October to February, the optimum tilt angle has been determined to be 0° and, from March to September, the optimum tilt angle is observed to be 25°. There are only two seasonal adjustments that are needed for PV solar panels in Zomba district and these should be carried out at the end of February and at the end of September. For fixed solar panels with no seasonal adjustments, the optimum tilt angle for the PV solar panels that are northfacing has been determined to be 25°.

  12. On the simplifications for the thermal modeling of tilting-pad journal bearings under thermoelastohydrodynamic regime

    DEFF Research Database (Denmark)

    Cerda Varela, Alejandro Javier; Fillon, Michel; Santos, Ilmar

    2012-01-01

    The relevance of calculating accurately the oil film temperature build up when modeling tilting-pad journal bearings is well established within the literature on the subject. This work studies the feasibility of using a thermal model for the tilting-pad journal bearing which includes a simplified...

  13. Patients with severe acquired brain injury show increased arousal in tilt-table training

    DEFF Research Database (Denmark)

    Riberholt, Christian G; Thorlund, Jonas Bloch; Mehlsen, Jesper;

    2013-01-01

    Patients with severe acquired brain injury (ABI) are often mobilised using a tilt-table. Complications such as orthostatic intolerance have been reported. The primary objective of this study was to investigate if using a tilt-table was feasible for mobilising patients with severe ABI admitted...

  14. Effect of compression paddle tilt correction on volumetric breast density estimation.

    Science.gov (United States)

    Kallenberg, Michiel G J; van Gils, Carla H; Lokate, Mariëtte; den Heeten, Gerard J; Karssemeijer, Nico

    2012-08-21

    For the acquisition of a mammogram, a breast is compressed between a compression paddle and a support table. When compression is applied with a flexible compression paddle, the upper plate may be tilted, which results in variation in breast thickness from the chest wall to the breast margin. Paddle tilt has been recognized as a major problem in volumetric breast density estimation methods. In previous work, we developed a fully automatic method to correct the image for the effect of compression paddle tilt. In this study, we investigated in three experiments the effect of paddle tilt and its correction on volumetric breast density estimation. Results showed that paddle tilt considerably affected accuracy of volumetric breast density estimation, but that effect could be reduced by tilt correction. By applying tilt correction, a significant increase in correspondence between mammographic density estimates and measurements on MRI was established. We argue that in volumetric breast density estimation, tilt correction is both feasible and essential when mammographic images are acquired with a flexible compression paddle.

  15. Leg blood flow measurements using venous occlusion plethysmography during head-up tilt.

    NARCIS (Netherlands)

    Kooijman, M.; Poelkens, F.; Rongen, G.A.; Smits, P.; Hopman, M.T.E.

    2007-01-01

    We tested whether venous occlusion plethysmography (VOP) is an appropriate method to measure calf blood flow (CBF) during head-up tilt (HUT). CBF measured with VOP was compared with superficial femoral artery blood flow as measured by Doppler ultrasound during incremental tilt angles. Measurements o

  16. SYSTEMATIC ERROR REDUCTION: NON-TILTED REFERENCE BEAM METHOD FOR LONG TRACE PROFILER.

    Energy Technology Data Exchange (ETDEWEB)

    QIAN,S.; QIAN, K.; HONG, Y.; SENG, L.; HO, T.; TAKACS, P.

    2007-08-25

    Systematic error in the Long Trace Profiler (LTP) has become the major error source as measurement accuracy enters the nanoradian and nanometer regime. Great efforts have been made to reduce the systematic error at a number of synchrotron radiation laboratories around the world. Generally, the LTP reference beam has to be tilted away from the optical axis in order to avoid fringe overlap between the sample and reference beams. However, a tilted reference beam will result in considerable systematic error due to optical system imperfections, which is difficult to correct. Six methods of implementing a non-tilted reference beam in the LTP are introduced: (1) application of an external precision angle device to measure and remove slide pitch error without a reference beam, (2) independent slide pitch test by use of not tilted reference beam, (3) non-tilted reference test combined with tilted sample, (4) penta-prism scanning mode without a reference beam correction, (5) non-tilted reference using a second optical head, and (6) alternate switching of data acquisition between the sample and reference beams. With a non-tilted reference method, the measurement accuracy can be improved significantly. Some measurement results are presented. Systematic error in the sample beam arm is not addressed in this paper and should be treated separately.

  17. Motion sickness and tilts of the inertial force environment: active suspension systems vs. active passengers

    NARCIS (Netherlands)

    Golding, J.F.; Bles, W.; Bos, J.E.; Haynes, T.; Gresty, M.A.

    2003-01-01

    Maneuvering in vehicles exposes occupants to low frequency forces (<1 Hz) which can provoke motion sickness. Hypothesis: Aligning with the tilting inertial resultant (gravity + imposed horizontal acceleration: gravito-inertial force (GIF)) may reduce motion sickness when tilting is either 'active'

  18. Fabrication and Characterization of Tilted Fiber Optic Bragg Grating Filters over Various Wavelengths

    Science.gov (United States)

    Grant, Joseph; Jackson, Kurt V.; Wang, Y.; Sharma, A.; Burdine, Robert V. (Technical Monitor)

    2002-01-01

    Fiber Optic Bragg Grating taps are fabricated and characterized at various wavelengths using a modified Talbot interferometric technique. Gratings are fabricated by tilting the photosensitive fiber to angles up to 45 degrees w.r.t. the writing angle. Diffraction characteristics of the tilted grating is monitored in first and second orders.

  19. Motion sickness and tilts of the inertial force environment: active suspension systems vs. active passengers

    NARCIS (Netherlands)

    Golding, J.F.; Bles, W.; Bos, J.E.; Haynes, T.; Gresty, M.A.

    2003-01-01

    Maneuvering in vehicles exposes occupants to low frequency forces (<1 Hz) which can provoke motion sickness. Hypothesis: Aligning with the tilting inertial resultant (gravity + imposed horizontal acceleration: gravito-inertial force (GIF)) may reduce motion sickness when tilting is either 'active' (

  20. The Application of Normal Stress Reduction Function in Tilt Tests for Different Block Shapes

    Science.gov (United States)

    Kim, Dong Hyun; Gratchev, Ivan; Hein, Maw; Balasubramaniam, Arumugam

    2016-08-01

    This paper focuses on the influence of the shapes of rock cores, which control the sliding or toppling behaviours in tilt tests for the estimation of rock joint roughness coefficients (JRC). When the JRC values are estimated by performing tilt tests, the values are directly proportional to the basic friction of the rock material and the applied normal stress on the sliding planes. Normal stress obviously varies with the shape of the sliding block, and the basic friction angle is also affected by the sample shapes in tilt tests. In this study, the shapes of core blocks are classified into three representative shapes and those are created using plaster. Using the various shaped artificial cores, a set of tilt tests is carried out to identify the shape influences on the normal stress and the basic friction angle in tilt tests. The test results propose a normal stress reduction function to estimate the normal stress for tilt tests according to the sample shapes based on Barton's empirical equation. The proposed normal stress reduction functions are verified by tilt tests using artificial plaster joints and real rock joint sets. The plaster joint sets are well matched and cast in detailed printed moulds using a 3D printing technique. With the application of the functions, the obtained JRC values from the tilt tests using the plaster samples and the natural rock samples are distributed within a reasonable JRC range when compared with the measured values.

  1. AromaDeg, a novel database for phylogenomics of aerobic bacterial degradation of aromatics.

    Science.gov (United States)

    Duarte, Márcia; Jauregui, Ruy; Vilchez-Vargas, Ramiro; Junca, Howard; Pieper, Dietmar H

    2014-01-01

    Understanding prokaryotic transformation of recalcitrant pollutants and the in-situ metabolic nets require the integration of massive amounts of biological data. Decades of biochemical studies together with novel next-generation sequencing data have exponentially increased information on aerobic aromatic degradation pathways. However, the majority of protein sequences in public databases have not been experimentally characterized and homology-based methods are still the most routinely used approach to assign protein function, allowing the propagation of misannotations. AromaDeg is a web-based resource targeting aerobic degradation of aromatics that comprises recently updated (September 2013) and manually curated databases constructed based on a phylogenomic approach. Grounded in phylogenetic analyses of protein sequences of key catabolic protein families and of proteins of documented function, AromaDeg allows query and data mining of novel genomic, metagenomic or metatranscriptomic data sets. Essentially, each query sequence that match a given protein family of AromaDeg is associated to a specific cluster of a given phylogenetic tree and further function annotation and/or substrate specificity may be inferred from the neighboring cluster members with experimentally validated function. This allows a detailed characterization of individual protein superfamilies as well as high-throughput functional classifications. Thus, AromaDeg addresses the deficiencies of homology-based protein function prediction, combining phylogenetic tree construction and integration of experimental data to obtain more accurate annotations of new biological data related to aerobic aromatic biodegradation pathways. We pursue in future the expansion of AromaDeg to other enzyme families involved in aromatic degradation and its regular update. Database URL: http://aromadeg.siona.helmholtz-hzi.de

  2. A tomographic algorithm to determine tip-tilt information from laser guide stars

    Science.gov (United States)

    Reeves, A. P.; Morris, T. J.; Myers, R. M.; Bharmal, N. A.; Osborn, J.

    2016-06-01

    Laser Guide Stars (LGS) have greatly increased the sky-coverage of Adaptive Optics (AO) systems. Due to the up-link turbulence experienced by LGSs, a Natural Guide Star (NGS) is still required, preventing full sky-coverage. We present a method of obtaining partial tip-tilt information from LGSs alone in multi-LGS tomographic LGS AO systems. The method of LGS up-link tip-tilt determination is derived using a geometric approach, then an alteration to the Learn and Apply algorithm for tomographic AO is made to accommodate up-link tip-tilt. Simulation results are presented, verifying that the technique shows good performance in correcting high altitude tip-tilt, but not that from low altitudes. We suggest that the method is combined with multiple far off-axis tip-tilt NGSs to provide gains in performance and sky-coverage over current tomographic AO systems.

  3. A tomographic algorithm to determine tip-tilt information from laser guide stars

    CERN Document Server

    Reeves, A P; Myers, R M; Bharmal, N A; Osborn, J

    2016-01-01

    Laser Guide Stars (LGS) have greatly increased the sky-coverage of Adaptive Optics (AO) systems. Due to the up-link turbulence experienced by LGSs, a Natural Guide Star (NGS) is still required, preventing full sky-coverage. We present a method of obtaining tip-tilt information from LGSs alone in multi-LGS tomographic LGS AO systems. The method of LGS up-link tip-tilt determination is derived using a geometric approach, then an alteration to the Learn and Apply algorithm for tomographic AO is made to accommodate up-link tip-tilt. Simulation results are presented, verifying that the technique shows good performance in correcting high altitude tip-tilt, but not that from low altitudes. We suggest that the method is combined with far off-axis tip-tilt NGS to provide gains in performance and sky-coverage over current tomographic AO systems.

  4. Tilted seat position for non-ambulant individuals with neurological and neuromuscular impairment: a systematic review.

    Science.gov (United States)

    Michael, S M; Porter, D; Pountney, T E

    2007-12-01

    To determine the effects of tilt-in-space seating on outcomes for people with neurological or neuromuscular impairment who cannot walk. Search through electronic databases (MEDLINE, Embase, CINAHL, AMED). Discussions with researchers who are active in field. Selection criteria included interventional studies that investigated the effects of seat tilt on outcome or observational studies that identified outcomes for those who had used tilt-in-space seating in populations with neurological or neuromuscular impairments. Two reviewers independently selected trials for inclusion, assessed quality and extracted data. Nineteen studies were identified which fulfilled the selection criteria. Seventeen of these were essentially before-after studies investigating the immediate effects of tilting the seating. All studies looked at populations with neurological impairment, and most were on children with cerebral palsy (n=8) or adults with spinal cord injury (n=8). REVIEWER'S CONCLUSION: Posterior tilt can reduce pressures at the interface under the pelvis.

  5. Performance verification of focus variation and confocal microscopes measuring tilted ultra-fine surfaces

    DEFF Research Database (Denmark)

    Quagliotti, Danilo; Baruffi, Federico; Tosello, Guido

    2016-01-01

    The behaviour of two optical instruments, scilicet a laser scanning confocal microscope and a focus-variation microscope, was investigated considering measurements of tilted surfaces. The measured samples were twelve steel artefacts for mould surface finish reference, covering Sa roughness...... parameter in the range (101—103) nm. The 3D surface texture parameters considered were Sa, Sq and Sdq. The small working distance of the confocal microscope objectives influenced the measurement setup, preventing from selecting a high tilting angle. The investigation was carried out comparing measurements...... of flat surfaces (0° tilt) with measurements of 12.5° tilted surfaces. The confocal microscope results showed a high sensitivity to tilting due to the laser beam reflection on the metal surfaces. The focus variation microscope results were more robust with respect to the considered angular variation...

  6. Tilt angle dependence of the modulated interference effects in photo-elastic modulators

    Science.gov (United States)

    Talukder, Md. Abdul Ahad; Geerts, Wilhelmus J.

    2017-05-01

    The effect of the PEM tilt angle and incident polarization on the PEM interference is studied for a single axis photo-elastic modulator. The dc, 1ω , and 2ω components of the detector signal vary periodically as a function of PEM tilt angle. Although it is possible to adjust the PEM tilt angle to minimize the 1ω or 2ω detector signal at small tilt angles, it is not possible to null both of them simultaneously. For the case where no analyzer is used, the ac detector signals can be minimized simultaneously by adjusting the polarization angle of the light incident on the PEM and the PEM tilt angle. Direct observations of the detector signal indicate that the effects of refraction index and thickness variations are opposite consistent with a lower polarizability for compressive strain of the modulator.

  7. Tilt angle dependence of the modulated interference effects in photo-elastic modulators

    Directory of Open Access Journals (Sweden)

    Md. Abdul Ahad Talukder

    2017-05-01

    Full Text Available The effect of the PEM tilt angle and incident polarization on the PEM interference is studied for a single axis photo-elastic modulator. The dc, 1ω, and 2ω components of the detector signal vary periodically as a function of PEM tilt angle. Although it is possible to adjust the PEM tilt angle to minimize the 1ω or 2ω detector signal at small tilt angles, it is not possible to null both of them simultaneously. For the case where no analyzer is used, the ac detector signals can be minimized simultaneously by adjusting the polarization angle of the light incident on the PEM and the PEM tilt angle. Direct observations of the detector signal indicate that the effects of refraction index and thickness variations are opposite consistent with a lower polarizability for compressive strain of the modulator.

  8. Increasing the sensitivity for tilt measurement using a cyclic interferometer with multiple reflections

    Science.gov (United States)

    Pretheesh Kumar, Valiyaparambil Chacko; Joenathan, Charles; Ganesan, Angarai; Somasundram, Umapathy

    2016-08-01

    Measurement of tilt plays an important role in metrological applications and consequently, several methods have been proposed in the recent past. Classical interferometric methods can measure angles with high accuracy but are easily susceptible to external turbulences. We propose to use a cyclic interferometer to measure tilt in which the sensitivity to tilt measurement is double when compared with that of the classical Michelson interferometer. Since the counter propagating beams travel identical paths, the interferometer is insensitive to external vibrations and turbulence and thus can be used under harsh environmental conditions. The novelty in the technique lies in creating multiple reflections in the tilt mirror to enhance the measurement accuracy by the way of increasing the sensitivity. This paper presents the basics of the interferometer and experimental results to quantify the increase in sensitivity. By increasing the number of reflections, it is shown that sensitivity can be further improved to measure tilt angles below 5 μrad.

  9. Investigating Of Proper Photovoltaic Panel Tilt Angle to Be Used As Shading Device inKuwait

    Directory of Open Access Journals (Sweden)

    Hussain Bunyan

    2015-01-01

    Full Text Available Photovoltaic panels can act as power generator as well as external shading devices with proper tilt angle. In this paper we will study the performance of a Silicon Photovoltaic system with different tilt angle arrangement in Kuwait (latitude 30˚ N. In the study the PV system is installed facing south to collectmaximum solar radiation at noon. The angle is varied from 00 to 900 , during full year at the Solstice (the time at which the day and night come into balance and Equinox (the end of the day’s increase or decrease in day night hours periods, to achieve optimum tilt angle, higher in magnitude than 30 0 with competitive output power. The results show that the performance and the output power of the PV system with 50˚ tilt angle, is equivalent to the corresponding values at tilt angle equal to Kuwait latitude (30˚ during the whole year.

  10. Hi-GAL, the Herschel infrared Galactic Plane Survey: photometric maps and compact source catalogues. First data release for Inner Milky Way: +68{\\deg}> l > -70{\\deg}

    CERN Document Server

    Molinari, S; Elia, D; Pestalozzi, M; Traficante, A; Pezzuto, S; Swinyard, B M; Noriega-Crespo, A; Bally, J; Moore, T J T; Plume, R; Zavagno, A; di Giorgio, A M; Liu, S J; Pilbratt, G L; Mottram, J C; Russeil, D; Piazzo, L; Veneziani, M; Benedettini, M; Calzoletti, L; Faustini, F; Natoli, P; Piacentini, F; Merello, M; Palmese, A; Del Grande, R; Polychroni, D; Rygl, K L J; Polenta, G; Barlow, M J; Bernard, J -P; Martin, P G; Testi, L; Ali, B; Andrè, P; Beltrán, M T; Billot, N; Brunt, C; Carey, S; Cesaroni, R; Compiègne, M; Eden, D; Fukui, Y; Garcia-Lario, P; Hoare, M G; Huang, M; Joncas, G; Lim, T L; Lord, S D; Martinavarro-Armengol, S; Motte, F; Paladini, R; Paradis, D; Peretto, N; Robitaille, T; Schilke, P; Schneider, N; Schulz, B; Sibthorpe, B; Strafella, F; Thompson, M A; Umana, G; Ward-Thompson, D; Wyrowski, F

    2016-01-01

    (Abridged) We present the first public release of high-quality data products (DR1) from Hi-GAL, the {\\em Herschel} infrared Galactic Plane Survey. Hi-GAL is the keystone of a suite of continuum Galactic Plane surveys from the near-IR to the radio, and covers five wavebands at 70, 160, 250, 350 and 500 micron, encompassing the peak of the spectral energy distribution of cold dust for 8 l > -70{\\deg} in a |b|<1{\\deg} latitude strip. Photometric maps have been produced with the ROMAGAL pipeline, that optimally capitalizes on the excellent sensitivity and stability of the bolometer arrays of the {\\em Herschel} PACS and SPIRE photometric cameras, to deliver images of exquisite quality and dynamical range, absolutely calibrated with {\\em Planck} and {\\em IRAS}, and recovering extended emission at all wavelengths and all spatial scales. The compact source catalogues have been generated with the CuTEx algorithm, specifically developed to optimize source detection and extraction in the extreme conditions of intens...

  11. The Günther-Tulip retrievable filter: a method for assessing tilting of the filter.

    Science.gov (United States)

    Semiz-Oysu, Aslihan; Cho, Kyung J

    2010-04-01

    Tilting of the Günther-Tulip filter may be responsible for failure or difficulty to retrieve. Assessment of the filter tilt can be difficult when only AP imaging is available. This study is performed in vitro to develop a simple method to assess the Günther-Tulip filter for tilting. A model consisting of a plastic tube was used to simulate vena cava. A Günther-Tulip filter was placed centred or tilted within the tube at various positions and radiograms were taken in AP, lateral, and craniocaudally angled projections. The images were analysed to determine the actual degree of tilt, the distance between the limb hooks on AP radiograms and the craniocaudal angulation degree needed to align the limb hooks linearly. When the filter was centred or tilted laterally, all limb hooks of the filter were aligned linearly on AP radiograms. When the filter was tilted in AP or oblique direction, linear alignment of the limb hooks was lost and the ventral and dorsal limb hooks showed separation on AP projection. The amount of separation and the craniocaudal angles to align the filter hooks corresponded to actual tilt angles. Loss of linear alignment of limb hooks in AP radiograms may suggest the presence of tilt in the AP plane. Significant separation of limb hooks should be alarming for significant filter tilt, and further evaluation of the filter position by CT scan or lateral cavogram should be obtained prior to planning of the retrieval. Copyright 2009 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier B.V. All rights reserved.

  12. 15d-6°头低位卧床对女性运动心肺功能影响及对抗措施效果%Effects of 15 d -6° Head-down Bed Rest on Female Cardiopulmonary Function and Effectiveness of Some Countermeasures.

    Institute of Scientific and Technical Information of China (English)

    刘炳坤; 白延强; 陈文娟; 李志利; 祝郁; 张丽芬; 周湘杰; 王林杰; 唐国华; 李莹辉

    2011-01-01

    目的 明确15 d模拟失重对女性运动心肺功能的影响,同时考核自行车功量计锻炼+下体负压的综合防护效果.方法 22名青年女性健康志愿者,随机分为对照组(CON,n=8)、下体负压组(LBNP,n=7)和自行车功量计+下体负压组(ERGO+LLBNP,n=7).对照组仅进行15 d-6°头低位卧床;LBNP组在第6,8,10天各进行1次下体负压基础锻炼,负压-10~-40 mmHg,总持续时间20 min;在第12,13天各进行1次下体负压强化锻炼,负压-20~-40 mmHg,总持续时间55 min.ERGO+LBNP在15d卧床期间进行每2 d休息1 d的卧位自行车功量计锻炼,每次30 min,锻炼强度40%~80%最大耗氧量(Vo2max),其下体负压锻炼制度同LBNP组.在卧床实验前后分别对上述3组进行运动心肺功能、运动心电和血压测量.结果 卧床后与卧床前相比,对照组和LBNP组的最大耗氧量、最大相对耗氧量、代谢当量、氧脉搏、最大功率、持续时间均有显著降低(P<0.05或P<0.01).ERGO+LBNP组除了最大功率和持续时间有降低(P<0.05)外,Vo2max等其它参数均无明显变化.结论 15 d头低位卧床可导致女性运动心肺功能明显下降,中等强度自行车功量计锻炼+下体负压的综合防护基本能够维持其有氧运动能力,下体负压对其运动心肺功能下降没有防护作用.%Objective To determine the effects of 15 d -6° head down bed rest (HDBR) on female cardiopulmonary function and effectiveness of some countermeasures.Methods After a 7 d ambulatory adaptation to controlled confinement and diet, 22 healthy young female volunteers participated in a 15 d -6° HDBR and were assigned randomly to each group.Control group( CON,n = 8) performed no countermeasure.Lower body negative pressure group ( LBNP, n = 7 ) performed the basic LBNP on the 6th, 8th, 10th day respectively, and the negative pressure was ranged from -10 ~ -40 mmHg, and whole duration was 20 min.Then, they performed the intensive LBNP exercise on the 12th and

  13. 45天-6°头低位卧床对个体额区EEG偏侧化和情绪的影响%Effects of 45 Days-6°Head-down Bed Rest on Males’ Frontal Alpha Asymmetry and Emotion

    Institute of Scientific and Technical Information of China (English)

    修利超; 谈诚; 蒋依涵; 周仁来; 陈善广

    2014-01-01

    Suffering from the anxiety and depression under spaceflight may impair astronauts’ cognitive performance. It is difficult to investigate human emotion changes in real space environment. Previous studies suggested that the head-down bed rest (HDBR) which simulated weightlessness environment was used to evaluate emotion changes with self-reported scales and turned out to be useful tools. In addition, scientific research suggests that emotional responses are composed of initial emotional reactivity and ongoing emotion regulation. However, it is still uncertain that whether the emotion regulation competence will be impaired or not under HDBR. Therefore, we investigated the effects of 45 day-6° HDBR on participants’ self-reported anxiety and depression as well as the frontal EEG asymmetry which represents their emotion regulation competence. Sixteen healthy non-smoking young men whose mean age was 26.33 years old (SD=4.13) were recruited in the experiment. The participants had no history of chronic or acute diseases and normal vision. They were right-handed, non-athletes and none of them were allowed to use medication, tobacco, or caffeine-containing drinks during the experiment. They should keep lying in the bed with-6 degree for 45 days. EEG data and Beck Anxiety Inventory (BAI) as well as the Beck Depression Inventory (BDI) were assessed and analyzed on two days before HDBR, 11th, 20th, 32nd and 40th day under HDBR together with the 8th day after HDBR respectively. According to the previous studies, we mainly measured EEG alpha asymmetry in the frontal area (FP1, FP2, F3 and F4) and the EEG was referenced on-line to the left mastoid and re-referenced off-line to the Cz electrode. Throughout the EEG recording, the impedance of the electrodes was maintained under 5 kΩ. The electroencephalogram (EEG) was recorded by 40 Ag/AgCl electrodes mounted on a custom-made cap according to the extended 10-20 system and continuously sampled at 1000 Hz by a Neuroscan Nu

  14. Environmental fatigue behaviors of wrought and cast stainless steels in 310 .deg. C Deoxygenated Water

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Pyung Yeon

    2011-02-15

    Environmental fatigue behaviors of wrought type 316LN stainless steel and cast CF8M stainless steel were investigated. LCF tests were performed at fixed strain rate of 0.04%/s with 0.4%, 0.6%, 0.8%, 1.0% strain amplitudes in 310 .deg. C deoxygenated water environment. In addition, to analyze microstructure effect on fatigue behavior, low cycle fatigue tests in air environment were performed at fixed strain rate of 0.4%/s, 0.04%/s with 0.4%, 0.8% strain amplitudes. It was shown that the low cycle fatigue life of CF8M in a 310 .deg. C deoxygenated water environment was slightly longer than that of 316LN. On the other hand, the low cycle fatigue life of CF8M in a 310 .deg. C air environment was slightly shorter than that of 316LN or was similar with that of 316LN. Through OM observation and phase image analysis, it was confirmed that the ferrite content of CF8M tested in a 310 .deg. C deoxygenated water environment was larger than that of CF8M tested in a 310 .deg. C air environment. It was shown that the ferrite phase fraction of CF8M tested in 310 .deg. C deoxygenated water environment was approximately 26∼28% and that of CF8M tested in air environment was approximately 10∼12%. The difference of ferrite content in CF8M results in superior tensile properties as higher ferrite content. Furthermore, the difference of ferrite content in CF8M might be the cause of different result of fatigue life between CF8M and 316LN depending on environment. In this study, focused on CF8M having 26∼28% ferrite content, to understand the causes of these differences in a 310 .deg. C deoxygenated water environment, fracture surface and crack morphology were observed. And material factors like microstructure, mechanical properties factors like stress behavior during fatigue life, factors by environmentally assisted cracking (EAC) like hydrogen induced cracking (HIC) and chemical compositions of both materials were analyzed. Mainly in a 310 .deg. C deoxygenated water environment, the

  15. Wind-tunnel force and flow visualization data at Mach numbers from 1.6 to 4.63 for a series of bodies of revolution at angles of attack from minus 4 deg to 60 deg

    Science.gov (United States)

    Landrum, E. J.; Babb, C. D.

    1979-01-01

    Flow visualization and force data for a series of six bodies of revolution are presented without analysis. The data were obtained in the Langley Unitary Plan wind tunnel for angles of attack from -4 deg to 60 deg. The Reynolds number used for these tests was 6,600,000 per meter.

  16. Pourbaix diagrams for the system copper-chlorine at 5-100 deg C

    Energy Technology Data Exchange (ETDEWEB)

    Beverskog, B. [Studsvik Material AB, Nykoeping (Sweden); Puigdomenech, I. [Studsvik Eco and Safety AB, Nykoeping (Sweden)

    1998-04-01

    Pourbaix diagrams for the copper-chlorine system in the temperature interval 5-100 deg C have been revised. Predominance diagrams for dissolved copper containing species have also been calculated. Two different total concentrations of each dissolved element, 10{sup -4} and 10{sup -6} molal for copper and 0.2 and 1.5 molal for chlorine have been used in the calculations. Chloride is the predominating chlorine species in aqueous solutions. Presence of chloride increases the corrosion regions of copper at the expense of the immunity and passivity regions in the Pourbaix diagrams. CuCl{sub 2} {center_dot} 3Cu(OH){sub 2} is the only copper-chloride solid phase that forms at the concentrations of chlorine studied. However, its stability area decreases with increasing temperature. The ion CuCl{sub 2}{sup -} predominates at all temperatures at [Cl(aq)]{sub tot}=0.2 molal and this reduces the immunity and passivity areas. A corrosion region exists between the immunity and passivity regions at 100 deg C at [Cu(aq)]{sub tot}=10{sup -6} and [Cl(aq)]{sub tot}=0.2 molal. At the chlorine concentration of 1.5 molal the corrosion region exists in the whole temperature range investigated. The ion CuCl{sub 3}{sup 2-} predominates at 5-25 and 100 deg C, while CuCl{sub 2}{sup -} predominates at 50-80 deg C at [Cl(aq)]{sub tot=}1-5 molal. A copper concentration of 10{sup -4} molal reduces the corrosion areas due to expansion of the immunity and passivity areas. However, a corrosion region still exists between the immunity and passivity regions at all investigated temperatures at pH{sub {Tau}}<9.5 and 1.5 molal chloride concentration. According to our calculations the copper canisters in the deep nuclear waste repository should not corrode at the copper concentration of 10{sup -6} molal and the chloride concentration of 0.2 molal. However, at 80-100 deg C the equilibrium potentials postulated for the Swedish nuclear repository are dangerously close to a corrosion situation. According to

  17. Book review, Igiene e Tecnologie degli Alimenti di Origine Animale Giampaolo Colavita (a cura di

    Directory of Open Access Journals (Sweden)

    Manuel Graziani

    2008-09-01

    Full Text Available Igiene e Tecnologie degli Alimenti di Origine Animale si avvale del contributo di 33 autori, tutti soci dell’Associazione Italiana Veterinari Igienisti (AIVI, che garantiscono l’appropriata trattazione di una materia estremamente vasta e dinamica. Il manuale nasce da un’iniziativa finalizzata alla realizzazione di un testo che rifletta e possa soddisfare le esigenze didattiche degli insegnamenti di un’ampia serie di materie universitarie: Igiene e Tecnologie degli Alimenti di Origine Animale della Facoltà di Medicina Veterinaria, di Agraria, nei corsi di Scienze e Tecnologie Alimentari, di Scienze e Tecnologie delle Produzioni Animali, nel corso di laurea in Tecniche della Prevenzione nell’ambiente e nei Luoghi di Lavoro, nonché in altri corsi di studio dove si insegnano le discipline relative all’igiene e alla sicurezza degli alimenti.Sono stati trattati gran parte degli alimenti di origine animale, i prodotti a base di carne, il latte e i prodotti derivati, i prodotti della pesca freschi e trasformati, i prodotti dell’alveare, le uova e gli ovoprodotti. Di particolare interesse appare il capitolo riguardante la diagnostica analitica degli alimenti, considerato che le moderne metodologie analitiche risultano fondamentali per affrontare le tematiche legate all’igiene e alla sicurezza alimentare.Il volume ha una finalità prevalentemente didattica ma è comunque rivolto a tutti coloro che operano nel campo dell’Igiene e delle Tecnologie Alimentari. Infatti, visti gli argomenti trattati come le tossinfezioni e le intossicazioni alimentari, la conservazione, il confezionamento e l’etichettatura dei prodotti alimentari, anche i professionisti del settore possono trarre dal testo elementi utili per la loro attività. Per esempio argomenti quali l’analisi del rischio, le attività di audit ed i sistemi di accreditamento e di certificazione sono particolarmente utili per chi opera nelle Aziende Sanitarie Locali e negli Istituti

  18. 偏倾斜模和倾斜模的分次与非分次性质%Graded and Nongraded Properties of Partial Tilting Modules and Tilting Modules

    Institute of Scientific and Technical Information of China (English)

    郑敏; 陈清华

    2009-01-01

    This paper gives the relationships among partial tilting objects(tilting objects)of categories of graded left A-modules of type G,left A-modules,left Ae-modules and A#G-modules,and then proves that for graded partial tilting modules,there exist the Bongartz complements in the category of graded A-modules.

  19. Sea level variabilities in the Gulf Stream between Cape Hatteras and 50 deg W - A Geosat study

    Science.gov (United States)

    Vazquez, Jorge; Zlotnicki, Victor; Fu, Lee-Lueng

    1990-01-01

    Sea level variabilities in the Gulf Stream between Cape Hatteras and 50 deg W were examined by studying sea level residuals, relative to a 2-yr mean sea level, obtained from Geosat altimetry data for the period between November 1986 and December 1988. An array of sea-level time series was constructed for a region bounded by 30 deg N and 45 deg N in latitude and by 80 deg W and 50 deg W longitude. It is shown that the spectral characteristics of this time series varies with geographic location along the Gulf Stream path. Concurrent NOAA IR images are used to aid in the interpretation of sea level observations in terms of the variability of the stream's path, demonstrating the synergistic value of the combination of satellite-altimeter and IR data.

  20. Creep crack growth in a reactor pressure vessel steel at 360 deg C

    Energy Technology Data Exchange (ETDEWEB)

    Rui Wu; Seitisleam, F.; Sandstroem, R. [Swedish Institute for Metals Research, Stockholm (Sweden)

    1998-12-31

    Plain creep (PC) and creep crack growth (CCG) tests at 360 deg C and post metallography were carried out on a low alloy reactor pressure vessel steel (ASTM A508 class 2) with different microstructures. Lives for the CCG tests were shorter than those for the PC tests and this is more pronounced for simulated heat affected zone microstructure than for the parent metal at longer lives. For the CCG tests, after initiation, the cracks grew constantly and intergranularly before they accelerated to approach rupture. The creep crack growth rate is well described by C*. The relations between reference stress, failure time and steady crack growth rate are presented for the CCG tests. It is demonstrated that the failure stress due to CCG is considerably lower than the yield stress at 360 deg C. Consequently, the CCG will control the static strength of a reactor vessel. (orig.) 17 refs.

  1. The first winter solstice observed at the meridian line of Santa Maria degli Angeli in Rome

    CERN Document Server

    Sigismondi, Costantino

    2014-01-01

    The page written by the astronomer Francesco Bianchini (1662-1729) and containing the data of the 1701 winter solstice observed at Santa Maria degli Angeli is presented for the first time in figure 2 and widely discussed along this paper. The great meridian line in the Basilica of Santa Maria degli Angeli in Rome was built in 1701/1702 with the scope to measure the Obliquity of the Earth's orbit in the following eight centuries, upon the will of pope Clement XI. During the winter solstice of 1701 the first measurements of the obliquity have been realized by Francesco Bianchini, the astronomer who designed the meridian line, upgrading the similar instrument realized by Giandomenico Cassini in San Petronio, Bononia. In this paper the accuracy of the data observed by Francesco Bianchini is discussed and compared with up-to-date ephemerides. The modern situation of this historical instrument is also presented.

  2. Isothermal section at 1400 deg. C of the Ti-Zr-Sn system

    Energy Technology Data Exchange (ETDEWEB)

    Saltykov, V.A. [I.N. Frantsevich Institute for Problems of Materials Science, Str. Krzhyzhanovsky, 3, Kiev 03142 (Ukraine)], E-mail: ssaltykov@ipms.kiev.ua; Meleshevich, K.A.; Samelyuk, A.V.; Verbytska, O.M.; Bulanova, M.V. [I.N. Frantsevich Institute for Problems of Materials Science, Str. Krzhyzhanovsky, 3, Kiev 03142 (Ukraine)

    2008-07-14

    By the methods of X-ray diffraction, metallography and microprobe examinations the character of phase equilibria at 1400 deg. C is studied for the Ti-(Ti,Zr){sub 5}Sn{sub 3}-Zr region of the Ti-Zr-Sn system. The isothermal section at 1400 deg. C is constructed. This is similar to the solidus surface and is characterized by two 3-phase regions: <{beta}Ti,Zr> + Ti{sub 3}Sn + (Ti,Zr){sub 5}Sn{sub 3} and Ti{sub 3}Sn + Ti{sub 2}Sn + (Ti,Zr){sub 5}Sn{sub 3}. Solubility of Sn in <{beta}Ti,Zr> solid solution is between 10 and 15 at.% Sn. Solubility of zirconium in Ti{sub 3}Sn is about 12 at.%.

  3. Iron oxidation kinetics study by using infrared spectral emissivity measurements below 570deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Campo, Leire del [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologi' a, Universidad del Pai' s Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Perez-Saez, Raul B. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologi' a, Universidad del Pai' s Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Instituto de Sintesis y Estudio de Materiales, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao (Spain)], E-mail: raul.perez@ehu.es; Tello, Manuel J. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologi' a, Universidad del Pai' s Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Instituto de Sintesis y Estudio de Materiales, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao (Spain)

    2008-01-15

    The oxidation kinetics of iron below 570deg. C is investigated through the dependence of the spectral emissivity on the surface oxidation state. Using the theory of radiative effects of thin films, the oxide scale thickness is obtained as a function of time. A parabolic growth has been observed in all the cases, and applying Wagner's theory, the oxidation parabolic rate constants have been calculated at four temperatures. The temperature dependence of these results has additionally been used to obtain the activation energy of the oxidation process in iron. The parabolic rate constants and activation energy values are in good agreement with the theoretical predictions, and this suggests that the lattice diffusion mechanisms for the high temperature magnetite growth also occur until 400deg. C. The experimental results are also useful to test the applicability of emissivity measurements for in situ oxidation kinetics studies in the spectral range where the scales are optically thin.

  4. Millimeter and sub-millimeter heterodyne mixing based on 2DEG hot-electron bolometers

    Science.gov (United States)

    Wang, Kai; Bell, Matthew; Ramaswamy, Rahul; Sergeev, Andrei; Strasser, Gottfried; Mitin, Vladimir

    2010-03-01

    We investigate GHz and THz heterodyne mixer based on the electron heating effect of a two-dimensional electron gas (2DEG) by electromagnetic radiation at liquid nitrogen temperatures (77K). The devices are fabricated from AlGaAs/GaAs heterostructures with a channel width of 150 μm and lengths varying from 3-20 μm. Steady-state measurements are used to investigate electron heating in these devices and determine basic parameters, such as electron-phonon energy relaxation time and electron heat capacity. We perform mixing experiments at ˜100 GHz frequency range with two Gunn diodes as the radiation sources, and find that electron heating is the primary mixing mechanism at these frequencies. For the mixing experiments at ˜ 2 terahertz range, a quantum cascade laser (QCL) is employed as the local oscillator. To optimize our device, we also investigate electron kinetics and transport properties in the 2DEG hot-electron bolometer.

  5. Twenty-degree-tilt radiography for evaluation of lateral humeral condylar fracture in children

    Energy Technology Data Exchange (ETDEWEB)

    Imada, Hideaki; Tanaka, Ryuji; Itoh, Yohei; Kishi, Kazuhiko [National Hospital Organization, Higashi-Hiroshima Medical Center, Department of Orthopedic Surgery, Higashi Hiroshima, Hiroshima (Japan)

    2010-03-15

    To investigate the efficacy of '20 -tilt anteroposterior (A-P) radiography' in the assessment of lateral condylar fractures of the distal humerus. Eighteen children with lateral humeral condylar fractures were studied. Every child underwent conventional A-P and lateral radiography, and six children underwent multi-detector computed tomography (MDCT). For the investigation of 20 -tilt radiography, ten children with lateral humeral condylar fractures had conventional and 20 -tilt A-P and lateral radiography both preoperatively and postoperatively. Fragment dislocation was measured at the lateral and medial margins of the fracture on both the conventional A-P and 20 -tilt A-P radiographs. The lateral condylar fragment was triangular and was most prominent posteriorly. The fracture line was typically tilted approximately 20 to a reference line perpendicular to the long axis of the humerus in the lateral view. The extent of dislocation at the lateral and medial margins of the fracture site by 20 -tilt A-P radiography (9.3 {+-} 3.6 mm and 5.6 {+-} 2.5 mm) was significantly wider than that measured by the conventional method (6.8 {+-} 4.1 mm and 2.0 {+-} 1.5 mm), which may influence treatment. Twenty-degree-tilt A-P radiography may more precisely demonstrate fragment dislocation than standard radiographs and may influence patient treatment. (orig.)

  6. Early Poststroke Rehabilitation Using a Robotic Tilt-Table Stepper and Functional Electrical Stimulation

    Directory of Open Access Journals (Sweden)

    Alexey N. Kuznetsov

    2013-01-01

    Full Text Available Background. Stroke frequently leaves survivors with hemiparesis. To prevent persistent deficits, rehabilitation may be more effective if started early. Early training is often limited because of orthostatic reactions. Tilt-table stepping robots and functional electrical stimulation (FES may prevent these reactions. Objective. This controlled convenience sample study compares safety and feasibility of robotic tilt-table training plus FES (ROBO-FES and robotic tilt-table training (ROBO against tilt-table training alone (control. A preliminary assessment of efficacy is performed. Methods. Hemiparetic ischemic stroke survivors (age years, days after stroke were assigned to 30 days of ROBO-FES (, ROBO (, or control ( in addition to conventional physical therapy. Impedance cardiography and transcranial doppler sonography were performed before, during, and after training. Hemiparesis was assessed using the British Medical Research Council (MRC strength scale. Results. No serious adverse events occurred; 8 patients in the tilt-table group prematurely quit the study because of orthostatic reactions. Blood pressure and CBFV dipped % during robot training. In 52% of controls mean arterial pressure decreased by %. ROBO-FES increased leg strength by points, ROBO by more than control (, . CBFV increased in both robotic groups more than in controls (. Conclusions. Robotic tilt-table exercise with or without FES is safe and may be more effective in improving leg strength and cerebral blood flow than tilt table alone.

  7. Sunspot group tilt angles and the strength of the solar cycle

    CERN Document Server

    Dasi-Espuig, Maria; Krivova, Natasha A; Cameron, Robert H; Peñuela, Tania

    2010-01-01

    It is known that the tilt angles of active regions increase with their latitude (Joy's law). It has never been checked before, however, whether the average tilt angles change from one cycle to another. Flux transport models show the importance of tilt angles for the reversal and build up of magnetic flux at the poles which is, in turn, correlated with the strength of the next cycle. Here we analyse time series of tilt angle measurements and look for a possible relationship of the tilt angles with other solar cycle parameters, in order to glean information on the solar dynamo and to estimate their potential for predictions of solar activity. We employ tilt angle data from Mount Wilson and Kodaikanal observatories covering solar cycles 15 to 21. We analyse the latitudinal distribution of the tilt angles (Joy's law), their variation from cycle to cycle and their relationship to other solar cycle parameters, such as the strength, amplitude and length. The two main results are: 1. An anti-correlation between the m...

  8. Evaluation of peripapillary choroidal and retinal nerve fiber layer thickness in eyes with tilted optic disc

    Directory of Open Access Journals (Sweden)

    Muammer Ozcımen

    2014-12-01

    Full Text Available Purpose: This study was performed to evaluate the retinal nerve fiber layer (RNFL and peripapillary choroidal thickness in eyes with tilted optic disc in order to identify characteristic RNFL and peripapillary choroid patterns verified by optical coherence tomography (OCT. Methods: Twenty-nine eyes of 29 patients with tilted optic discs were studied with spectral-domain (SD-OCT and compared with age and sex-matched control subjects in a prospective design. The imaging of RNFL was performed using circular scans of a diameter of 3.4 mm around the optic disc using OCT. For measurements of peripapillary choroidal thickness, the standar d protocol for RNFL assessment was performed. Results: SD-OCT indicated significantly lower superotemporal (p<0.001, superonasal (p=0.001, and global (p=0.005 RNFL thicknesses in the tilted disc group than those of the control group. Peripapillary choroid was significantly thicker at the site of the elevated rim of eyes with tilted disc (p<0.001. Conclusion: This study demonstrated a clinical characterization of the main tilted disc morphologies that may be helpful in differentiating a tilted disc from other altered disc morphologies. Further studies are recommended to study the comparison between glaucoma and tilted disc groups.

  9. Tilted microstrip phased arrays with improved electromagnetic decoupling for ultrahigh-field magnetic resonance imaging.

    Science.gov (United States)

    Pang, Yong; Wu, Bing; Jiang, Xiaohua; Vigneron, Daniel B; Zhang, Xiaoliang

    2014-12-01

    One of the technical challenges in designing a dedicated transceiver radio frequency (RF) array for MR imaging in humans at ultrahigh magnetic fields is how to effectively decouple the resonant elements of the array. In this work, we propose a new approach using tilted microstrip array elements for improving the decoupling performance and potentially parallel imaging capability. To investigate and validate the proposed design technique, an 8-channel volume array with tilted straight-type microstrip elements was designed, capable for human imaging at the ultrahigh field of 7 Tesla. In this volume transceiver array, its electromagnetic decoupling behavior among resonant elements, RF field penetration to biological samples, and parallel imaging performance were studied through bench tests and in vivo MR imaging experiments. In this specific tilted element array design, decoupling among array elements changes with the tilted angle of the elements and the best decoupling can be achieved at certain tilted angle. In vivo human knee MR images were acquired using the tilted volume array at 7 Tesla for method validation. Results of this study demonstrated that the electromagnetic decoupling between array elements and the B1 field strength can be improved by using the tilted element method in microstrip RF coil array designs at the ultrahigh field of 7T.

  10. Tilt Angle and Footpoint Separation of Small and Large Bipolar Sunspot Regions Observed with HMI

    Science.gov (United States)

    McClintock, B. H.; Norton, A. A.

    2016-02-01

    We investigate bipolar sunspot regions and how tilt angle and footpoint separation vary during emergence and decay. The Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory collects data at a higher cadence than historical records and allows for a detailed analysis of regions over their lifetimes. We sample the umbral tilt angle, footpoint separation, and umbral area of 235 bipolar sunspot regions in Helioseismic and Magnetic Imager—Debrecen Data with an hourly cadence. We use the time when the umbral area peaks as time zero to distinguish between the emergence and decay periods of each region and we limit our analysis of tilt and separation behavior over time to within ±96 hr of time zero. Tilt angle evolution is distinctly different for regions with small (≈30 MSH), midsize (≈50 MSH), and large (≈110 MSH) maximum umbral areas, with 45 and 90 MSH being useful divisions for separating the groups. At the peak umbral area, we determine median tilt angles for small (7.°6), midsize (5.°9), and large (9.°3) regions. Within ±48 hr of the time of peak umbral area, large regions steadily increase in tilt angle, midsize regions are nearly constant, and small regions show evidence of negative tilt during emergence. A period of growth in footpoint separation occurs over a 72-hr period for all of the regions from roughly 40 to 70 Mm. The smallest bipoles (Jaramillo et al. (2015) results that the sunspots appear to be two distinct populations.

  11. Determination of Solar Collector Optimum Tilt Angle for Ankara and Districts

    Directory of Open Access Journals (Sweden)

    Abdülkadir KOÇER

    2016-04-01

    Full Text Available This study that is Ankara province and districts based deals with the determination of the optimum tilt angle to maximize the performances of solar collector and solar panel. In Ankara, fixed solar collectors are usually placed at slope of 40°. In this study, annual optimum tilt angle for Ankara province and districts was calculated as 34°±1 however the optimum angles during the year were calculated between 1° and 67°. The results of this study are compared with similar studies in the literature they were found to be consistent with the results of similar studies. Also, the tilt angle was calculated for the six months periods as 15° and 56°, for seasonal periods (winter, spring, summer, autumn as 62°, 23°, 6° and 49°, respectively and solar radiation for optimum angles of inclination were found. When the tilt angle is changed only twice a year, due to increasing the amount of energy per unit area, according to the annual tilt angle fixed product they provides energy efficiency by about 5%. On the other hand, when the tilt angle is changed every month this ratio can be reached approximately 8%. For increasing the utilization efficiency of solar collectors and panels, it is recommended adjusting of the tilt angle once a month or at least twice a year.

  12. Web server for tilt-pair validation of single particle maps from electron cryomicroscopy.

    Science.gov (United States)

    Wasilewski, Sebastian; Rosenthal, Peter B

    2014-04-01

    Three-dimensional structures of biological assemblies may be calculated from images of single particles obtained by electron cryomicroscopy. A key step is the correct determination of the orientation of the particle in individual image projections. A useful tool for validation of the quality of a 3D map and its consistency with images is tilt-pair analysis. In a successful tilt-pair test, the relative angle between orientations assigned to each image of a tilt-pair agrees with the known relative rotation angle of the microscope specimen holder during the experiment. To make the procedure easy to apply to the increasing number of single particle maps, we have developed software and a web server for tilt-pair analysis. The tilt-pair analysis program reports the overall agreement of the assigned orientations with the known tilt angle and axis of the experiment and the distribution of tilt transformations for individual particles recorded in a single image field. We illustrate application of the validation tool to several single particle specimens and describe how to interpret the scores.

  13. ({alpha},{eta}) phase diagrams in tilted chiral smectics

    Energy Technology Data Exchange (ETDEWEB)

    Rjili, M., E-mail: medrjili@yahoo.fr [Laboratoire de Physique de la Matiere Molle et de la Modelisation Electromagnetique, Faculte des Sciences de Tunis, Universite Tunis El Manar, 2092 El Manar Tunis (Tunisia); Marcerou, J.P., E-mail: marcerou@crpp-bordeaux.cnrs.fr [Centre de Recherches Paul Pascal, 115, Av. Albert-Schweitzer, 33600 Pessac (France); Gharbi, A.; Othman, T. [Laboratoire de Physique de la Matiere Molle et de la Modelisation Electromagnetique, Faculte des Sciences de Tunis, Universite Tunis El Manar, 2092 El Manar Tunis (Tunisia)

    2013-02-01

    The polymorphism of tilted chiral smectics liquid crystals is incredibly rich and encompasses many subphases such as SmC{sub A}{sup Low-Asterisk }; SmC{sub Fi1}{sup Low-Asterisk }; SmC{sub Fi2}{sup Low-Asterisk }; SmC{sup Low-Asterisk }; SmC{sub {alpha}}{sup Low-Asterisk }. The continuum theory established by Marcerou (2010) is used to derive an expression for the free energy density of those subphases. The minimization of this free energy is obtained through a combination of analytical and numerical methods. It leads to a phase diagram built in the ({alpha},{eta}) plane where {alpha} is local angular parameter and {eta} describes the variation of the temperature. From this graphical representation, many experimentally observed phase sequences of ferroelectric liquid crystals can be explained, even them including subphases which were recently observed like the SmC{sub 5}{sup Low-Asterisk} and the SmC{sub 6}{sup Low-Asterisk} ones. However, it should be emphasized that the details of predicted phase diagram are strongly dependent on the compound studied.

  14. Simulations of thermal conductance across tilt grain boundaries in graphene

    Institute of Scientific and Technical Information of China (English)

    Peng Wang; Bo Gong; Qiong Feng; Hong-Tao Wang

    2012-01-01

    Non-equilibrium molecular dynamics (MD) method was performed to simulate the thermal transportation process in graphene nanoribbons (GNRs).A convenient way was conceived to introduce tilt grain boundaries (GBs) into the graphene lattice by repetitive removing C atom rows along certain directions.Comprehensive MD simulations reveal that larger-angle GBs are effective thermal barriers and substantially reduce the average thermal conductivity of GNRs.The GB thermal conductivity is ~ 10 W.m-1·K-1 for a bicrystal GNR with a misorientation of 21.8°,which is ~97% less than that of a prefect GNR with the same size.The total thermal resistance has a monotonic dependence on the density of the 5-7 defects along the GBs.A theoretical model is proposed to capture this relation and resolve the contributions by both the reduction in the phonon mean free path and the defect-induced thermal resistance.

  15. Tilt table test today-state of the art

    Institute of Scientific and Technical Information of China (English)

    Nicholay Teodorovich; Moshe Swissa

    2016-01-01

    A tilt table test(TTT) is an inexpensive, noninvasive tool for the differential diagnosis of syncope and orthostatic intolerance and has good diagnostic yield. The autonomic system malfunction which underlines the reflex syncope is manifested as either hypotension or bradycardia, while an orthostatic challenge is applied. The timing of the response to the orthostatic challenge, as well as the predominant component of the response help to differentiate between various forms of neurocardiogenic syncope, orthostatic hypotension and non-cardiovascular conditions(e.g., pseudosyncope). Medications, such as isoproterenol and nitrates, may increase TTT sensitivity. Sublingual nitrates are easiest to administer without the need of venous access. TTT can be combined with carotid sinus massage to evaluate carotid sinus hypersensitivity, which may not be present in supine position. TTT is not useful to access the response to treatment. Recently, implantable loop recorders(ILR) have been used to document cardioinhibitory reflex syncope, because pacemakers are beneficial in many of these patients, especially those over 45 years of age. The stepwise use of both TTT and ILR is a promising approach in these patients. Recently, TTT has been used for indications other than syncope, such as assessment of autonomic function in Parkinson’s disease and its differentiation from multiple system atrophy.

  16. "Tilt" in color space: Hue changes induced by chromatic surrounds.

    Science.gov (United States)

    Klauke, Susanne; Wachtler, Thomas

    2015-01-01

    The perceived color of a chromatic stimulus is influenced by the chromaticity of its surround. To investigate these influences along the dimension of hue, we measured hue changes induced in stimuli of different hues by isoluminant chromatic surrounds. Generally, induced hue changes were directed in color space away from the hue of the inducing surround and depended on the magnitude on the hue difference between stimulus and surround. With increasing difference in hue between stimulus and surround, induced hue changes increased up to a maximum and then decreased for larger differences. This qualitative pattern was similar for different inducers, but quantitatively, induction was weaker along some directions in cone-opponent color space than along other directions. The strongest induction effects were found along an oblique, blue-yellow axis that corresponds to the daylight axis. The overall pattern of the induction effect shows similarities to the well-known tilt effect, where shifts in perceived angle of oriented stimuli are induced by oriented surrounds. This suggests analogous neural representations and similar mechanisms of contextual processing for different visual features such as orientation and color.

  17. Simulation Analysis of Tilted Polyhedron-Shaped Thermoelectric Elements

    Science.gov (United States)

    Meng, Xiangning; Suzuki, Ryosuke O.

    2015-06-01

    The generation of thermoelectricity is considered a promising approach to harness the waste heat generated in industries, automobiles, gas fields, and other man-made processes. The waste heat can be converted to electricity via a thermoelectric (TE) generator. In this light, the generator performance depends on the geometric configuration of its constituent elements as well as their material properties. Our previous work reported TE behaviors for modules consisting of parallelogram-shaped elements, because elements with tilted laminate structures provide increased mechanical stability and efficient heat-transferring ability from the hot surface to the cold surface. Here, we study TE elements in the shape of a polyhedron that is obtained by mechanically truncating the edges of a parallelogram element in order to further enhance the generator performance and reduce TE material usage. The TE performance of the modules consisting of these polyhedron elements is numerically simulated by using the finite-volume method. The output power, voltage, and current of the polyhedral TE module are greater than those of the parallelogram-element module. The polyhedron shape positively affects heat transfer and the flow of electric charges in the light of increasing the efficiency of conversion from heat to electricity. By varying the shape of the truncated portions, we determine the optimal shape that enables homogeneous heat flux distribution and slow diffusion of thermal energy to obtain the better efficiency of conversion of heat into electricity. We believe that the findings of our study can significantly contribute to the design policy in TE generation.

  18. Tilt aftereffect following adaptation to translational Glass patterns.

    Science.gov (United States)

    Pavan, Andrea; Hocketstaller, Johanna; Contillo, Adriano; Greenlee, Mark W

    2016-03-23

    Glass patterns (GPs) consist of randomly distributed dot pairs (dipoles) whose orientations are determined by specific geometric transforms. We assessed whether adaptation to stationary oriented translational GPs suppresses the activity of orientation selective detectors producing a tilt aftereffect (TAE). The results showed that adaptation to GPs produces a TAE similar to that reported in previous studies, though reduced in amplitude. This suggests the involvement of orientation selective mechanisms. We also measured the interocular transfer (IOT) of the GP-induced TAE and found an almost complete IOT, indicating the involvement of orientation selective and binocularly driven units. In additional experiments, we assessed the role of attention in TAE from GPs. The results showed that distraction during adaptation similarly modulates the TAE after adapting to both GPs and gratings. Moreover, in the case of GPs, distraction is likely to interfere with the adaptation process rather than with the spatial summation of local dipoles. We conclude that TAE from GPs possibly relies on visual processing levels in which the global orientation of GPs has been encoded by neurons that are mostly binocularly driven, orientation selective and whose adaptation-related neural activity is strongly modulated by attention.

  19. PUMA-PUblication MAnagement: sistemi per la gestione delle pubblicazioni degli enti di ricerca

    OpenAIRE

    Biagioni, Stefania

    2005-01-01

    Lo scopo di questa presentazione ? quello di illustrare i) come ? stato realizzato un ciclo gestionale completo dell'informazione: dall'inserimento dei metadati e dei documenti digitali alla restituzione degli stessi all'utente finale; ii) come sono stati resi accessibili via web, a livelli diversi e secondo viste diverse l'informazione prodotta; iii) come siano stati creati servizi differenti utilizzando gli stessi oggetti. Vengono illustrati i sistemi utilizzati presso il CNR di Pisa per la...

  20. Proteomica degli exosomi urinari per la ricerca di biomarcatori nella nefropatia diabetica e nelle tubulopatie ereditarie

    OpenAIRE

    Corbetta,

    2015-01-01

    Le urine costituiscono il fluido biologico di elezione nella ricerca di biomarcatori per le patologie renali in quanto possono essere raccolte in modo semplice e non invasivo; una strategia per la semplificazione del proteoma urinario è rappresentata dall’isolamento degli exosomi urinari (UE), nanovescicole di membrana (30-100 nm) rilasciate dalle cellule epiteliali nello spazio urinario. In questo lavoro abbiamo focalizzato l’attenzione sulla nefropatia diabetica (DN), una comune complicazio...

  1. Observation of Polar Mesosphere Summer Echoes using the Northernmost MST Radar at Eureka (80 deg N)

    Science.gov (United States)

    Swarnalingam, N.; Hocking, W.; Janches, D.; Drummond, J.

    2017-01-01

    We investigate long-term Polar Mesosphere Summer Echoes (PMSEs) observations conducted by the northern most geographically located MST radar at Eureka (80 deg N, 86 deg W). While PMSEs are a well recognized summer phenomenon in the polar regions, previous calibrated studies at Resolute Bay and Eureka using 51.5 MHz and33 MHz radars respectively, showed that PMSE backscatter signal strengths are relatively weak in the polar cap sites, compared to the auroral zone sites (Swarnalingam et al., 2009b; Singer et al., 2010). Complications arise with PMSEs in which the echo strength is controlled by the electrons, which are, in turn, influenced by heavily charged ice particles as well as the variability in the D-region plasma. In recent years, PMSE experiments were conducted inside the polar cap utilizing a 51 MHz radar located at Eureka. In this paper, we investigate calibrated observations, conducted during 2009-2015. Seasonal and diurnal variations of the backscatter signal strengths are discussed and compared to previously published results from the ALOMAR radar, which is a radar of similar design located in the auroral zone at Andenes, Norway (69 deg N, 16 deg E). At Eureka, while PMSEs are present with a daily occurrence rate which is comparable to the rate observed at the auroral zone site for at least two seasons, they show a great level of inter-annual variability. The occurrence rate for the strong echoes tends to be low. Furthermore, comparison of the absolute backscatter signal strengths at these two sites clearly indicates that the PMSE backscatter signal strength at Eureka is weak. Although this difference could be caused by several factors, we investigate the intensity of the neutral air turbulence at Eureka from the measurements of the Doppler spectrum of the PMSE backscatter signals. We found that the level of the turbulence intensity at Eureka is weak relative to previously reported results from three high latitude sites.

  2. Survey of the sky at the 8. 7 and 14. 4 GHz frequencies in the 0 deg - 4 deg declination range

    Energy Technology Data Exchange (ETDEWEB)

    Amirkhanyan, V.R.; Gorshkov, A.G.; Kapustkin, A.A.; Konnikova, V.K.; Lazutkin, A.N.; Larionov, M.G.; Nikanorov, A.S.; Sidorenkov, V.N.; Ugol' kova, L.S.; Khromov, O.I. (Moskovskij Gosudarstvennyj Univ. (USSR). Gosudarstvennyj Astronomicheskij Inst. ' ' GAISh' ' )

    Using the RATAN-600 radiotelescope of the USSR Academy of Sciences (from March 1979 to January 1980) the sky is observed at the 8.7 and 14.4 GHz frequencies in the 0-4 deg declination range. Lists of 82 and 24 radiosources detected at the given frequencies are presented. Six radiosources are detected for the first time. Right ascension and declination, as well as the maximum values of radio-frequency radiation fluxes are given. The problems of measuring accuracies of fluxes and coordinates and the problem of validity of detected radiosources are discussed. On the basis of comparison of the data obtained with those in other works the systematic deviation in fluxes of sources is not more than 7%.

  3. Submillimeter wavelength survey of the galactic plane from l = -5 deg to l = +62 deg - Structure and energetics of the inner disk

    Science.gov (United States)

    Hauser, M. G.; Silverberg, R. F.; Stier, M. T.; Kelsall, T.; Gezari, D. Y.; Dwek, E.; Walser, D.; Mather, J. C.; Cheung, L. H.

    1984-01-01

    Observational results are presented from a new large-scale survey of the first quadrant of the galactic plane at wavelengths of 150, 250, and 300 microns, with a 10 x 10 arcmin beam. The emission detected in the survey arises from compact sources, most of which are identified with known peaks of 5 GHz or CO emission, or both, and from an underlying diffuse background with a typical angular width of about 0.9 deg (FWHM) which accounts for most of the emission. A total of 80 prominent discrete sources are identified and characterized, of which about half have not previously been reported at far-infrared wavelengths. The total infrared luminosity within the solar circle is about 1 to 2 x 10 to the 10th solar luminosity, and is probably emitted by dust that resides in molecular clouds.

  4. Submillimeter wavelength survey of the galactic plane from l = -5 deg to l = +62 deg: Structure and energetics of the inner disk

    Science.gov (United States)

    Hauser, M. G.; Silverberg, R. F.; Stier, M. T.; Kelsall, T.; Gezari, D. Y.; Dwek, E.; Walser, D.; Mather, J. C.; Cheung, L. H.

    1984-01-01

    Results from a large scale survey of the first quadrant of the Milky Way galactic plane at wavelengths of 150, 250, and 300 microns with a 10x10 arcmin beam are presented. The emission detected in the survey arises from compact sources, most of which are identified with known peaks of 5 GHz and/or CO emission, and from an underlying diffuse background with a typical angular width of approximately 0.9 deg (FWHM) which accounts for most of the emission. A total of 80 prominent discrete sources were identified and characterized, of which about half were not previously reported at far infrared wavelengths. The total infrared luminosity within the solar circle is approximately 1 to 2x10 to the 10th power L sub 0, and is probably emitted by dust that resides in molecular clouds.

  5. Combined influence of visual scene and body tilt on arm pointing movements: gravity matters!

    Science.gov (United States)

    Scotto Di Cesare, Cécile; Sarlegna, Fabrice R; Bourdin, Christophe; Mestre, Daniel R; Bringoux, Lionel

    2014-01-01

    Performing accurate actions such as goal-directed arm movements requires taking into account visual and body orientation cues to localize the target in space and produce appropriate reaching motor commands. We experimentally tilted the body and/or the visual scene to investigate how visual and body orientation cues are combined for the control of unseen arm movements. Subjects were asked to point toward a visual target using an upward movement during slow body and/or visual scene tilts. When the scene was tilted, final pointing errors varied as a function of the direction of the scene tilt (forward or backward). Actual forward body tilt resulted in systematic target undershoots, suggesting that the brain may have overcompensated for the biomechanical movement facilitation arising from body tilt. Combined body and visual scene tilts also affected final pointing errors according to the orientation of the visual scene. The data were further analysed using either a body-centered or a gravity-centered reference frame to encode visual scene orientation with simple additive models (i.e., 'combined' tilts equal to the sum of 'single' tilts). We found that the body-centered model could account only for some of the data regarding kinematic parameters and final errors. In contrast, the gravity-centered modeling in which the body and visual scene orientations were referred to vertical could explain all of these data. Therefore, our findings suggest that the brain uses gravity, thanks to its invariant properties, as a reference for the combination of visual and non-visual cues.

  6. RE-EXAMINING SUNSPOT TILT ANGLE TO INCLUDE ANTI-HALE STATISTICS

    Energy Technology Data Exchange (ETDEWEB)

    McClintock, B. H. [University of Southern Queensland, Toowoomba, 4350 (Australia); Norton, A. A. [HEPL, Stanford University, Palo Alto, CA 94305 (United States); Li, J., E-mail: u1049686@umail.usq.edu.au, E-mail: aanorton@stanford.edu, E-mail: jli@igpp.ucla.edu [Department of Earth, Planetary, and Space Sciences, University of California at Los Angeles, Los Angeles, CA 90095 (United States)

    2014-12-20

    Sunspot groups and bipolar magnetic regions (BMRs) serve as an observational diagnostic of the solar cycle. We use Debrecen Photohelographic Data (DPD) from 1974-2014 that determined sunspot tilt angles from daily white light observations, and data provided by Li and Ulrich that determined sunspot magnetic tilt angle using Mount Wilson magnetograms from 1974-2012. The magnetograms allowed for BMR tilt angles that were anti-Hale in configuration, so tilt values ranged from 0 to 360° rather than the more common ±90°. We explore the visual representation of magnetic tilt angles on a traditional butterfly diagram by plotting the mean area-weighted latitude of umbral activity in each bipolar sunspot group, including tilt information. The large scatter of tilt angles over the course of a single cycle and hemisphere prevents Joy's law from being visually identified in the tilt-butterfly diagram without further binning. The average latitude of anti-Hale regions does not differ from the average latitude of all regions in both hemispheres. The distribution of anti-Hale sunspot tilt angles are broadly distributed between 0 and 360° with a weak preference for east-west alignment 180° from their expected Joy's law angle. The anti-Hale sunspots display a log-normal size distribution similar to that of all sunspots, indicating no preferred size for anti-Hale sunspots. We report that 8.4% ± 0.8% of all bipolar sunspot regions are misclassified as Hale in traditional catalogs. This percentage is slightly higher for groups within 5° of the equator due to the misalignment of the magnetic and heliographic equators.

  7. Vortex lift augmentation by suction on a 60 deg swept Gothic wing

    Science.gov (United States)

    Taylor, A. H.; Jackson, L. R.; Huffman, J. K.

    1982-01-01

    An experimental investigation was conducted in the Langley high-speed 7- by 10-foot wind tunnel to determine the aerodynamic performance of suction applied near the wing tips above the trailing edge of a 60 deg swept Gothic wing. Moveable suction inlets were symmetrically mounted in the proximity of the trailing edge, and the amount of suction was varied to maximize wing lift. Tests were conducted at Mach 0.15, 0.30, and 0.45, and the angle of attack was varied from -4 to 50 deg. The suction augmentation increases the lift coefficient over the entire range of angle of attack. The lift improvement exceeds the unaugmented wing lift by over 20%. Moreover, the augmented lift exceeds the lift predicted by vortex lattice theory to 30 deg angle of attack. Suction augmentation is postulated to strengthen the vortex system by increasing its velocity and making it more concentrated. This causes the vortex breakdown to be delayed to a higher angle of attack

  8. submitter Technical Note: Using DEG-CPCs at upper tropospheric temperatures

    CERN Document Server

    Wimmer, D; Nieminen, T; Duplissy, J; Ehrhart, S; Almeida, J; Rondo, L; Franchin, A; Kreissl, F; Bianchi, F; Manninen, H E; Kulmala, M; Curtius, J; Petäjä, T

    2015-01-01

    Over the last few years, several condensation particle counters (CPCs) capable of measuring in the sub-3 nm size range have been developed. Here we study the performance of CPCs based on diethylene glycol (DEG) at different temperatures during Cosmics Leaving OUtdoor Droplets (CLOUD) measurements at CERN. The data shown here are the first set of verification measurements for sub-3 nm CPCs under upper tropospheric temperatures using atmospherically relevant aerosol particles. To put the results in perspective we calibrated the DEG-CPC at room temperature, resulting in a cut-off diameter of 1.4 nm. All diameters refer to mobility equivalent diameters in this paper. At upper tropospheric temperatures ranging from 246.15 K to 207.15 K, we found cut-off sizes relative to a particle size magnifier in the range of 2.5 to 2.8 nm. Due to low number concentration after size classification, the cut-off diameters have a high uncertainty (±0.3 nm) associated with them. Operating two laminar flow DEG-CPCs with different c...

  9. Sexy DEG/ENaC channels involved in gustatory detection of fruit fly pheromones.

    Science.gov (United States)

    Pikielny, Claudio W

    2012-11-06

    Hydrocarbon pheromones on the cuticle of Drosophila melanogaster modulate the complex courtship behavior of males. Recently, three members of the degenerin/epithelial Na+ channel (DEG/ENaC) family of sodium channel subunits, Ppk25, Ppk23, and Ppk29 (also known as Nope), have been shown to function in gustatory perception of courtship-modulating contact pheromones. All three proteins are required for the activation of male courtship by female pheromones. Specific interactions between two of them have been demonstrated in cultured cells, suggesting that, in a subset of cells where they are coexpressed, these three subunits function within a common heterotrimeric DEG/ENaC channel. Such a DEG/ENaC channel may be gated by pheromones, either directly or indirectly, or alternatively may control the excitability of pheromone-sensing cells. In addition, these studies identify taste neurons that respond specifically to courtship-modulating pheromones and mediate their effects on male behavior. Two types of pheromone-sensing taste neurons, F and M cells, have been defined on the basis of their specific response to either female or male pheromones. These reports set the stage for the dissection of the molecular and cellular mechanisms that mediate gustatory detection of contact pheromones.

  10. EDD, a novel phosphotransferase domain common to mannose transporter EIIA, dihydroxyacetone kinase, and DegV.

    Science.gov (United States)

    Kinch, Lisa N; Cheek, Sara; Grishin, Nick V

    2005-02-01

    Using a recently developed program (SCOPmap) designed to automatically assign new protein structures to existing evolutionary-based classification schemes, we identify a evolutionarily conserved domain (EDD) common to three different folds: mannose transporter EIIA domain (EIIA-man), dihydroxyacetone kinase (Dak), and DegV. Several lines of evidence support unification of these three folds into a single superfamily: statistically significant sequence similarity detected by PSI-BLAST; "closed structural grouping" using DALI Z-scores (each protein inside a group finds all other group members with scores higher than those to proteins outside the group) that includes only these proteins sharing a unique alpha-helical hairpin at the C-terminus and excludes all other proteins with similar topology; similar domain fusions connect Dak and DegV, and genomic neighborhood organizations connect Dak and EIIA-man. Finally, both Dak and EIIA-man perform similar phosphotransfer reactions, suggesting a phosphotransferase activity for the DegV-like family of proteins, whose function other than lipid binding revealed in the crystal structure remains unknown.

  11. Sauter-Schwinger like tunneling in tilted Bose-Hubbard lattices in the Mott phase

    CERN Document Server

    Queisser, Friedemann; Schützhold, Ralf

    2011-01-01

    We study the Mott phase of the Bose-Hubbard model on a tilted lattice. On the (Gutzwiller) mean-field level, the tilt has no effect -- but quantum fluctuations entail particle-hole pair creation via tunneling. For small potential gradients (long-wavelength limit), we derive a quantitative analogy to the Sauter-Schwinger effect, i.e., electron-positron pair creation out of the vacuum by an electric field. For large tilts, we obtain resonant tunneling related to Bloch oscillations.

  12. Eye torsion and the apparent horizon under head tilt and visual field rotation

    Science.gov (United States)

    Merker, B. H.; Held, R.

    1981-01-01

    Two different experimental manipulations, namely head tilt and the viewing of a visual display rotating around the line of sight, induce torsional displacements of the eyes and a tilting of the apparent horizon. The present study examines the routes by which visual (field rotation) and otolith-proprioceptive (head tilt) sources of afference influence horizon judgments. In particular, the relationship between torsional eye movements and horizon estimates is addressed. The results indicate that visual and otolith-proprioceptive information sum directly in their influence on eye torsion, but interact more complexly in horizon estimates, indicating a dissociation of their central determinants.

  13. The cone phase of liquid crystals: Triangular lattice of double-tilt cylinders

    Indian Academy of Sciences (India)

    Yashodhan Hatwalne; N V Madhusudana

    2003-08-01

    We predict the existence of a new defect-lattice phase near the nematic–smectic-C (NC) transition. This tilt-analogue of the blue phase is a lattice of double-tilt cylinders which are disclination lines in the smectic layer normal as well as the c-field. We discuss the structure and stability of the cone phase. We suggest that many ‘nematics’ exhibiting short range layering and tilt order may in fact be in the molten cone phase, which is a line liquid.

  14. Optimum Tilt Angle for Photovoltaic Solar Panels in Zomba District, Malawi

    OpenAIRE

    B. Kamanga; Mlatho, J. S. P.; Mikeka, C.; C. Kamunda

    2014-01-01

    A study to determine the optimum tilt angle for installing photovoltaic solar panels in Zomba district, Malawi, has been conducted. The study determined the optimum monthly tilt angles of PV solar panels and the seasonal adjustments needed for the panels in order to collect maximum solar radiation throughout the year. In this study, global solar radiation (GSR) on four tilted surfaces was measured. The north-facing surfaces were titled at angles of 0°, 15°, 20°, and 25°. The GSR data was used...

  15. Interpretation of Gravity Data using 3D Euler Deconvolution, Tilt Angle, Horizontal Tilt Angle and Source Edge Approximation of the North-West Himalaya

    Science.gov (United States)

    Ghosh, Gopal K.

    2016-08-01

    The collision of the Indian plate and the Eurasian plate created shortening and imbrications with thrusting and faulting which influences northward tectonic movement. This plate movement has divided the Himalaya into four parts, viz. Outer Himalaya, Lesser Himalaya, Greater Himalaya, and Tethys Himalaya. The crystalline basement rock plays an imperative role for structural and tectonic association. The study has been carried out near Rishikesh-Badrinath neighborhood in the northwestern part of the Himalayan girdle with multifarious tectonic set up with thrusted and faulted geological setting. In this study area, 3D Euler deconvolution, horizontal gradient analysis, tilt angle (TILT) and horizontal tilt angle (TDX) analysis have been carried out using gravity data to delineate the subsurface geology and heterogeneity in the northwestern part of Himalaya. The Euler depth solutions suggest the source depth of about 12 km and various derivative analyses suggest the trend of the delineation thrust-fault boundaries along with the dip and strike direction in the study area.

  16. 'Abnormal' angle response curves of TW/Rs for near zero tilt and high tilt channeling implants

    Energy Technology Data Exchange (ETDEWEB)

    Guo Baonian; Gossmann, Hans-Joachim; Toh, Terry; Colombeau, Benjamin; Todorov, Stan; Sinclair, Frank; Shim, Kyu-Ha; Henry, Todd [Applied Materials - Varian Semiconductor Equipment, 35 Dory Road, Gloucester, MA 01930 (United States)

    2012-11-06

    Angle control has been widely accepted as the key requirement for ion implantation in semiconductor device processing. From an ion implanter point of view, the incident ion direction should be measured and corrected by suitable techniques, such as XP-VPS for the VIISta implanter platform, to ensure precision ion placement in device structures. So called V-curves have been adopted to generate the wafer-based calibration using channeling effects as the Si lattice steer ions into a channeling direction. Thermal Wave (TW) or sheet resistance (Rs) can be used to determine the minimum of the angle response curve. Normally it is expected that the TW and Rs have their respective minima at identical angles. However, the TW and Rs response to the angle variations does depend on factors such as implant species, dose, and wafer temperature. Implant damage accumulation effects have to be considered for data interpretation especially for some 'abnormal' V-curve data. In this paper we will discuss some observed 'abnormal' angle responses, such as a) TW/Rs reverse trend for Arsenic beam, 2) 'W' shape of Rs Boron, and 3) apparent TW/Rs minimum difference for high tilt characterization, along with experimental data and TCAD simulations.

  17. Stable Isotopes of Tilted Ignimbrite Calderas in Nevada

    Science.gov (United States)

    John, D. A.; Watts, K. E.; Hofstra, A. H.; Colgan, J. P.; Henry, C.; Bindeman, I. N.

    2013-12-01

    Mid-Tertiary calderas are exceptionally well exposed in tilted fault blocks of the northern Great Basin, facilitating detailed evolutionary models of their magmatic-hydrothermal systems. The 29.4 Ma Job Canyon caldera, the oldest of 3 overlapping calderas in the Stillwater Range, west-central Nevada, is tilted ~90° exposing a 10-km-thick section of the crust. Large parts of the >7 km-diameter caldera system, including >2 km thickness of intracaldera rhyolitic tuff, lower parts of an ~2 km thick sequence of post-caldera intermediate lavas, and the upper 500 m of the resurgent granodioritic IXL pluton, were pervasively altered to propylitic, argillic, and sericitic assemblages. Sparse quartz×calcite veins cut the tuff. δ18O values of altered whole rock samples range from +4.8 to -9.1‰ but are mostly -6 to -9‰ at paleodepths >2 km. Calculated magmatic δ18O and δD values range from +6.4 to 8.2‰ and ~-70‰, respectively. Calculated fluid compositions using temperatures from fluid inclusions and mineral assemblages are δ18OH2O=-9.5 to -15‰ and δDH2O=-125 to -135‰ (chlorite) and -70 to -80‰ (epidote). Chlorite-whole rock data suggest fluids that were derived from moderately 18O-exchanged meteoric water. Fault blocks in north-central Nevada expose a >5 km upper crustal cross section through the 12-17 x 20 km, 34 Ma Caetano caldera, including >3 km thickness intracaldera rhyolitic Caetano Tuff. Asymmetric caldera subsidence left a depression >1 km deep partly filled with a lake. Magma resurgence and emplacement of shallow granite porphyry plutons drove a hydrothermal system that altered >120 km2 of the caldera to depths >1.5 km. Alteration was focused in an early granite porphyry intrusion and surrounding upper Caetano Tuff and lacustrine sediments. Early pervasive quartz-kaolinite-pyrite alteration grades outward and downward into more restricted quartz-illite/smectite-pyrite alteration. Hematite, quartz, and barite veins and hydrothermal breccias cut

  18. Description of multi-quasiparticle bands by the tilted axis cranking model 21.60.-n; High K rotational bands; Tilted axis cranking; Multi-quasiparticle configurations

    CERN Document Server

    Frauendorf, S

    2000-01-01

    The selfconsistent cranking approach is extended to the case of rotation about an axis which is tilted with respect to the principal axes of the deformed potential (Tilted Axis Cranking). Expressions for the energies and the intra bands electro-magnetic transition probabilities are given. The mean field solutions are interpreted in terms of quantal rotational states. The construction of the quasiparticle configurations and the elimination of spurious states is discussed. The application of the theory to high spin data is demonstrated by analyzing the multi-quasiparticle bands in the nuclides with N=102,103 and Z=71,72,73.

  19. Inactivation of the Deg protease family in the cyanobacterium Synechocystis sp. PCC 6803 has impact on the outer cell layers.

    Science.gov (United States)

    Cheregi, Otilia; Miranda, Hélder; Gröbner, Gerhard; Funk, Christiane

    2015-11-01

    The serine type Deg/HtrA proteases are distributed in a wide range of organisms from Escherichia coli to humans. The cyanobacterium Synechocystis sp. PCC 6803 possesses three Deg protease orthologues: HtrA, HhoA and HhoB. Previously we compared Synechocystis 6803 wild type cells exposed to mild or severe stress conditions with a mutant lacking all three Deg proteases and demonstrated that stress had strong impact on the proteomes and metabolomes. To identify the biochemical processes, which this protease family is involved in, here we compared Synechocystis sp. PCC 6803 wild type cells with a mutant lacking all three Deg proteases grown under normal growth conditions (30°C and 40 μmol photons m(-2) s(-1)). Deletion of the Deg proteases lead to the down-regulation of proteins related to the biosynthesis of outer cell layers (e.g. the GDP mannose 4,6-dehydratase) and affected protein secretion. During the late growth phase of the culture Deg proteases were found to be secreted to the extracellular medium of the Synechocystis sp. PCC 6803 wild type strain. While cyanobacterial Deg proteases seem to act mainly in the periplasmic space, deletion of the three proteases influences the proteome and metabolome of the whole cell. Impairments in the outer cell layers of the triple mutant might explain the higher sensitivity toward light and oxidative stress, which was observed earlier by Barker and coworkers. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Visual homing with a pan-tilt based stereo camera

    Science.gov (United States)

    Nirmal, Paramesh; Lyons, Damian M.

    2013-01-01

    Visual homing is a navigation method based on comparing a stored image of the goal location and the current image (current view) to determine how to navigate to the goal location. It is theorized that insects, such as ants and bees, employ visual homing methods to return to their nest. Visual homing has been applied to autonomous robot platforms using two main approaches: holistic and feature-based. Both methods aim at determining distance and direction to the goal location. Navigational algorithms using Scale Invariant Feature Transforms (SIFT) have gained great popularity in the recent years due to the robustness of the feature operator. Churchill and Vardy have developed a visual homing method using scale change information (Homing in Scale Space, HiSS) from SIFT. HiSS uses SIFT feature scale change information to determine distance between the robot and the goal location. Since the scale component is discrete with a small range of values, the result is a rough measurement with limited accuracy. We have developed a method that uses stereo data, resulting in better homing performance. Our approach utilizes a pan-tilt based stereo camera, which is used to build composite wide-field images. We use the wide-field images combined with stereo-data obtained from the stereo camera to extend the keypoint vector described in to include a new parameter, depth (z). Using this info, our algorithm determines the distance and orientation from the robot to the goal location. We compare our method with HiSS in a set of indoor trials using a Pioneer 3-AT robot equipped with a BumbleBee2 stereo camera. We evaluate the performance of both methods using a set of performance measures described in this paper.

  1. Forward dynamics simulation of human body under tilting perturbations

    Science.gov (United States)

    Naderi, D.; Pasha Zanoosi, A. A.; Sadeghi-Mehr, M.

    2012-02-01

    Human body uses different strategies to maintain its stability and these strategies vary from fixed-foot strategies to strategies which foot is moved in order to increase the support base. Tilting movement of foot is one type of the perturbations usually is exposed to human body. In the presence of such perturbations human body must employ appropriate reactions to prevent threats like falling. But it is not clear that how human body maintains its stability by central nervous system (CNS). At present study it is tried that by presenting a musculoskeletal model of human lower extremity with four links, three degrees of freedom (DOF) and eight skeletal muscles, the level of muscle activations causes the maintenance of stability, be investigated. Using forward dynamics solution, leads to a more general problem, rather than inverse dynamics. Hence, forward dynamics solution by forward optimization has been used for solving this highly nonlinear problem. To this end, first the system's equations of motion has been derived using lagrangian dynamics. Eight Hill-type muscles as actuators of the system were modeled. Because determination of muscle forces considering their number is an undetermined problem, optimization of an appropriate goal function should be practiced. For optimization problem, the characteristics of genetic algorithms as a method based on direct search, and the direct collocation method, has been profited. Also by considering requirements of problem, some constraints such as conservation of model stability are entered into optimization procedure. Finally to investigate validation of model, the results from optimization and experimental data are compared and good agreements are obtained.

  2. Probing the Universe's Tilt with the Cosmic Infrared Background Dipole

    Science.gov (United States)

    Fixsen, D. J.; Kashlinsky, A.

    2011-06-01

    Conventional interpretation of the observed cosmic microwave background (CMB) dipole is that all of it is produced by local peculiar motions. Alternative explanations requiring part of the dipole to be primordial have received support from measurements of large-scale bulk flows. A test of the two hypotheses is whether other cosmic dipoles produced by collapsed structures later than the last scattering coincide with the CMB dipole. One background is the cosmic infrared background (CIB) whose absolute spectrum was measured to ~30% by the COBE satellite. Over the 100-500 μm wavelength range its spectral energy distribution can provide a probe of its alignment with the CMB. This is tested with the COBE FIRAS data set which is available for such a measurement because of its low noise and frequency resolution which are important for Galaxy subtraction. Although the FIRAS instrument noise is in principle low enough to determine the CIB dipole, the Galactic foreground is sufficiently close spectrally to keep the CIB dipole hidden. A similar analysis is performed with DIRBE, which—because of the limited frequency coverage—provides a poorer data set. We discuss strategies for measuring the CIB dipole with future instruments to probe the tilt and apply it to the Planck, Herschel, and the proposed Pixie missions. We demonstrate that a future FIRAS-like instrument with instrument noise a factor of ~10 lower than FIRAS would make a statistically significant measurement of the CIB dipole. We find that the Planck and Herschel data sets will not allow a robust CIB dipole measurement. The Pixie instrument promises a determination of the CIB dipole and its alignment with either the CMB dipole or the dipole galaxy acceleration vector.

  3. Integrated polymer polarization rotator based on tilted laser ablation

    Science.gov (United States)

    Poulopoulos, Giannis; Kalavrouziotis, Dimitrios; Missinne, Jeroen; Bosman, Erwin; Van Steenberge, Geert; Apostolopoulos, Dimitrios; Avramopoulos, Hercules

    2017-02-01

    sidewalls, employing the tilted laser ablation technology, currently available at CMST. Therefore, the aforementioned simulation steps adhere fully to the respective design rules, taking into account the anticipated fabrication variations

  4. Measurements of sunspot group tilt angles for solar cycles 19-24

    Science.gov (United States)

    Isik, Seda; Isik, Emre

    2016-07-01

    The tilt angle of a sunspot group is a critical quantity in the surface transport magnetic flux on global scales, playing a role in the solar dynamo. To investigate Joy's law for four cycles, we measured the tilt angles of sunspot groups for solar cycles 19-24. We have developed an IDL routine, which allows the user to interactively select and measure sunspot positions and areas on the solar disc, using the sunspot drawing database of Kandilli Observatory. The method is similar to that used by others in the literature, with the exception that sunspot groups were identified manually, which has improved the accuracy of the tilt angles. We present cycle averages of the tilt angle and compare the results with the existing data in the literature.

  5. Contribution of perfusion pressure to vascular resistance response during head-up tilt

    Science.gov (United States)

    Imadojemu, V. A.; Lott, M. E.; Gleeson, K.; Hogeman, C. S.; Ray, C. A.; Sinoway, L. I.

    2001-01-01

    We measured brachial and femoral artery flow velocity in eight subjects and peroneal and median muscle sympathetic nerve activity (MSNA) in five subjects during tilt testing to 40 degrees. Tilt caused similar increases in MSNA in the peroneal and median nerves. Tilt caused a fall in femoral artery flow velocity, whereas no changes in flow velocity were seen in the brachial artery. Moreover, with tilt, the increase in the vascular resistance employed (blood pressure/flow velocity) was greater and more sustained in the leg than in the arm. The ratio of the percent increase in vascular resistance in leg to arm was 2.5:1. We suggest that the greater vascular resistance effects in the leg were due to an interaction between sympathetic nerve activity and the myogenic response.

  6. A novel control method for on-off gain and gain tilt of fiber Raman amplifiers

    Institute of Scientific and Technical Information of China (English)

    Xue Feng(冯雪); Wei Zhang(张巍); Xiaoming Liu(刘小明); Jiangde Peng(彭江得)

    2004-01-01

    Considering spectrum tilt due to signal-to-signal Raman scattering (SSRS) in backward distributed fiber Raman amplifiers (B-DFRA), an inverse tilted on-off gain profile is adopted to achieve flat net gain. A simple approximate linear relationship of pump power at each wavelength versus on-off gain level and tilt was derived numerically and experimentally so that a novel control method was established. Since there are only 3 pre-determinable constants required for individual pump wave, it is easy to be realized. As an example, maximum errors less than 0.2 and 0.4 dB respectively for average gain and gain tilt were achieved over C+L band in 100-km back-pumped standard single-mode fiber (SMF) experimentally.

  7. A mechanism for the dependence of sunspot group tilt angles on cycle strength

    CERN Document Server

    Işık, Emre

    2015-01-01

    The average tilt angle of sunspot groups emerging throughout the solar cycle determines the net magnetic flux crossing the equator, which is correlated with the strength of the subsequent cycle. I suggest that a deep-seated, non-local process can account for the observed cycle-dependent changes in the average tilt angle. Motivated by helioseismic observations indicating cycle-scale variations in the sound speed near the base of the convection zone, I determined the effect of a thermally perturbed overshoot region on the stability of flux tubes and on the tilt angles of emerging flux loops. I found that 5-20 K of cooling is sufficient for emerging flux loops to reproduce the reported amplitude of cycle-averaged tilt angle variations, suggesting that it is a plausible effect responsible for the nonlinearity of the solar activity cycle.

  8. Tilt meters for the Alignment System of the CMS Experiment: Users Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, J.; Arce, P.; Barcala, J.M.; Calvo, E.; Ferrando, A.; Josa, M.I.; Molinero, A.; Navarrete, J.; Oller, J.C.; Yuste, C.

    2007-09-27

    We present the instructions for the use of the electrolytic tilt meters installed in the link alignments system of the CMS experimental and give the Data Base to be used as a Handbook during CMS operation. (Author) 16 refs.

  9. Core Quadrant Power Tilt Induced by Control Rods Axial Position Mismatch

    Energy Technology Data Exchange (ETDEWEB)

    Son, Seungbeom; Lee, Changhee; Woo, Haeseuk; Jung, Yilsup [KEPCO Nuclear Fuel, Daejeon (Korea, Republic of); Kim, Yonghee [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    If the limits are not met, plant operation should be restricted at various conditions. Actually, core quadrant power tilt in many nuclear power plants has been occurred frequently. This study deals with the various general causes of the core quadrant power tilt, including the control rods axial position mismatch induced quadrant power tilt problem. Based on the simulation results in each control rods axial position mismatch in a same control bank, it was found that some control rods axial position mismatch (simply around 10 steps difference) can induce quadrant power tilt relatively high (around 1.5%). With the other causes induced QPT, it may exceed the technical specification limit (2%). So it is needed to drive the control rods in detail during the operation including power change mode.

  10. Tilt aftereffects in a self-organizing model of the primary visual cortex.

    Science.gov (United States)

    Bednar, J A; Miikkulainen, R

    2000-07-01

    RF-LISSOM, a self-organizing model of laterally connected orientation maps in the primary visual cortex, was used to study the psychological phenomenon known as the tilt aftereffect. The same self-organizing processes that are responsible for the long-term development of the map are shown to result in tilt aftereffects over short timescales in the adult. The model permits simultaneous observation of large numbers of neurons and connections, making it possible to relate high-level phenomena to low-level events, which is difficult to do experimentally. The results give detailed computational support for the long-standing conjecture that the direct tilt aftereffect arises from adaptive lateral interactions between feature detectors. They also make a new prediction that the indirect effect results from the normalization of synaptic efficacies during this process. The model thus provides a unified computational explanation of self-organization and both the direct and indirect tilt aftereffect in the primary visual cortex.

  11. Confocal X-ray fluorescence micro-spectroscopy experiment in tilted geometry

    Energy Technology Data Exchange (ETDEWEB)

    Czyzycki, Mateusz, E-mail: Mateusz.Czyzycki@desy.de [DESY Photon Science, Notkestr. 85, D-22607 Hamburg (Germany); AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Al. A. Mickiewicza 30, 30-059 Krakow (Poland); Wrobel, Pawel; Lankosz, Marek [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Al. A. Mickiewicza 30, 30-059 Krakow (Poland)

    2014-07-01

    This paper provides a generalized mathematical model to describe the intensity of primary X-ray fluorescence radiation collected in the tilted confocal geometry mode, where the collimating optics is rotated over an angle relative to a horizontal plane. The influence of newly introduced terms, which take into account the tilted geometry mode, is discussed. The model is verified with a multi-layer test sample scanned in depth. It is proved that for low-Z matrices, the rotation of the detection channel does not induce any significant differences in a reconstruction of the thickness and chemical composition of layers, so that it may safely be ignored. - Highlights: • A mathematical model for confocal XRF spectroscopy in tilted geometry was derived. • Tilted geometry influenced the analytical capabilities of XRF instrument slightly. • Thickness and the chemical composition of multi-layers were determined.

  12. Development of tilted fibre Bragg gratings using highly coherent 255 nm radiation

    Indian Academy of Sciences (India)

    O Prakash; J Kumar; R Mahakud; U Kumbhkar; S V Nakhe; S K Dixit

    2014-02-01

    This paper reports the study on development of tilted fibre Bragg gratings using highly coherent 255 nm radiation, obtained from the second harmonic generation (SHG) of copper vapour laser (CVL). The transmission and reflection spectra of the tilted fibre Bragg gratings (TFBG) were studied for the tilt angles of 0° (normal FBG), 1°, 3° and 4° between the fibre axis and the interference fringe plane. It was observed that as the angle of fibre axis and phase mask increased, the main Bragg peak shifted towards the higher wavelength and transmission dip decreased. The transmission dip of the cladding mode first increased and then decreased after reaching a maximum with the increase in the tilt angle.

  13. Reducing friction in tilting-pad bearings by the use of enclosed recesses

    DEFF Research Database (Denmark)

    Heinrichson, Niels; Santos, Ilmar

    2008-01-01

    A three-dimensional thermoelastohydrodynamic model is applied to the analysis of tilting-pad bearings with spherical pivots and equipped with deep recesses in the high-pressure regions. A potential for a 10-20% reduction in the friction loss compared to conventional plain bearing pads is documented....... Design suggestions minimizing the power loss are given for various length-to-width ratios. The tilting angle in the sliding direction is more sensitive to correct positioning of the pivot point than conventional bearing pads. Improving the performance by equipping a tilting-pad bearing with a deep recess...... therefore requires accurate analysis and design of the bearing. Similarly, a high sensitivity perpendicular to the sliding direction suggests that this method of reducing friction is more feasible when using line pivots or spring beds than when using spherical pivots for controlling the tilting angle....

  14. Modeling and experiment of the suspended seismometer concept for attenuating the contribution of tilt motion in horizontal measurements

    Science.gov (United States)

    Matichard, F.; Evans, M.; Mittleman, R.; MacInnis, M.; Biscans, S.; Dooley, K. L.; Sohier, H.; Lauriero, A.; Paris, H.; Koch, J.; Knothe, P.; Carbajo, A.; Dufort, C.

    2016-06-01

    Tilt-horizontal coupling in inertial sensors limits the performance of active isolation systems such as those used in gravitational wave detectors. Inertial rotation sensors can be used to subtract the tilt component from the signal produced by horizontal inertial sensors, but such techniques are often limited by the sensor noise of the tilt measurement. A different approach is to mechanically filter the tilt transmitted to the horizontal inertial sensor, as discussed in this article. This technique does not require an auxiliary rotation sensor and can produce a lower noise measurement. The concept investigated uses a mechanical suspension to isolate the inertial sensor from input tilt. Modeling and simulations show that such a configuration can be used to adequately attenuate the tilt transmitted to the instrument, while maintaining translation sensitivity in the frequency band of interest. The analysis is supported by experimental results showing that this approach is a viable solution to overcome the tilt problem in the field of active inertial isolation.

  15. Modeling and Experiment of the Suspended Seismometer Concept for Attenuating the Contribution of Tilt Motion in Horizontal Measurements

    CERN Document Server

    Matichard, F; Mittleman, R; McInnis, M; Biscans, S; Dooley, K L; Sohier, H; Lauriero, A; Paris, H; Koch, J; Knothe, P; Carbajo, A; Dufort, C

    2016-01-01

    Tilt-horizontal coupling in inertial sensors limits the performance of active isolation systems such as those used in gravitational wave detectors. Inertial rotation sensors can be used to subtract the tilt component from the signal produced by horizontal inertial sensors, but such techniques are often limited by the sensor noise of the tilt measurement. A different approach is to mechanically filter the tilt transmitted to the horizontal inertial sensor, as discussed in this article. This technique does not require an auxiliary rotation sensor, and can produce a lower noise measurement. The concept investigated uses a mechanical suspension to isolate the inertial sensor from input tilt. Modeling and simulations show that such a configuration can be used to adequately attenuate the tilt transmitted to the instrument, while maintaining translation sensitivity in the frequency band of interest. The analysis is supported by experimental results showing that this approach is a viable solution to overcome the tilt...

  16. Tilt stability in nonlinear programming under Mangasarian-Fromovitz constraint qualification

    OpenAIRE

    Mordukhovich, B. S.; Outrata, J. (Jiří)

    2013-01-01

    The paper concerns the study of tilt stability of local minimizers in standard problems of nonlinear programming. This notion plays an important role in both theoretical and numerical aspects of optimization and has drawn a lot of attention in optimization theory and its applications, especially in recent years. Under the classical Mangasarian–Fromovitz Constraint Qualification, we establish relationships between tilt stability and some other stability notions in constrained optimization. I...

  17. Multi-orifice active tilting-pad journal bearings—Harnessing of synergetic coupling effects

    DEFF Research Database (Denmark)

    Haugaard, Martin Asger; Santos, Ilmar

    2010-01-01

    The dynamic performance of tilting-pad journal bearings with controllable radial oil injection is theoretically investigated, exploring the synergetic effect between passive elastohydrodynamics and active radial lubricant injection. The flexible tilting-pads are modelled as linearly elastic using...... finite elements. To reduce computational work, a pseudo modal reduction is applied. Curves of dynamic bearing coefficients as well as the corresponding phase-magnitude plots are presented. Strong synergy between elastohydrodynamics and active control is observed, in particular for bearings with injection...

  18. Tilt-shift eddy current probe impact on information value of response signal

    OpenAIRE

    Chudacik Vladimir; Smetana Milan

    2016-01-01

    This article deals with the possibility for increasing of the informational value of a response signal using tilt-shift eddy current probe. Numerical simulations based on the FEM method using the OPERA 3D software as well as gained experimental results are presented. The simulated cracks are evaluated at the selected eddy current probe tilts and shifts with respect to conductive plate to obtain additional data needed for its evaluation and localization. Obtained simulation results are compare...

  19. Photosensitivity control of an isotropic medium through polarization of light pulses with tilted intensity front.

    Science.gov (United States)

    Kazansky, Peter G; Shimotsuma, Yasuhiko; Sakakura, Masaaki; Beresna, Martynas; Gecevičius, Mindaugas; Svirko, Yuri; Akturk, Selcuk; Qiu, Jianrong; Miura, Kiyotaka; Hirao, Kazuyuki

    2011-10-10

    We present the first experimental evidence of anisotropic photosensitivity of an isotropic homogeneous medium under uniform illumination. Our experiments reveal fundamentally new type of light induced anisotropy originated from the hidden asymmetry of pulsed light beam with a finite tilt of intensity front. We anticipate that the observed phenomenon, which enables employing mutual orientation of a light polarization plane and pulse front tilt to control interaction of matter with ultrashort light pulses, will open new opportunities in material processing.

  20. Tilting A Small Reflector For Vernier Pointing Of A Large Antenna

    Science.gov (United States)

    Veruttipong, Watt; Bathker, Dan A.

    1995-01-01

    Simple vernier pointing technique devised to facilitate scanning beam pointing of large paraboloidal reflector so line of sight of antenna sweeps out narrow cone about fixed axis (conical scan, also known as "conscan" in art). Scan effected by one of relatively small beam-waveguide reflectors or mirrors that couple signals between antenna and distant transmitting and/or receiving electronic circuits. Easier to tilt small mirror than to tilt massive antenna structure.

  1. Impaired tilt perception in Parkinson's disease: a central vestibular integration failure.

    Directory of Open Access Journals (Sweden)

    Giovanni Bertolini

    Full Text Available Impaired balance control is a hallmark symptom in Parkinson's disease (PD. Altered sensory-motor integration contributes to the deficiency. We aimed to determine whether impaired vestibular signal processing added to the disorder. We exposed patients (N = 11; 68±6y and age-matched healthy subjects (hS: N = 19; 65±11y on a motion platform in complete darkness to two consecutive forward tilt movements (12 series; N = 24; overall 288 trials and asked them to indicate which tilt was perceived larger. By combing tilt movements with translations we manipulated vestibular sensory input in order to investigate whether putative impairment resulted from a deficiency of the sensory organs (semicircular canals in 'single-SCC-cue-condition', otoliths in 'single-OT-cue-condition' themselves or to a sensory integration failure ('multi-cue-condition'.Tilt discrimination in the multi-cue-condition was inferior in patients compared to hS (p = 0.02. No significant differences between the two groups were found for both single-cue-conditions. Comparison of multi-cue-condition with a prediction resulting from the combination of both single-cue-conditions by optimal observer theory revealed that patients (p = 0.04, in contrast to hS, failed to efficiently combine SCC and OT information to improve tilt perception.We found that PD patients distinguished forward tilts less precise than hS, suggesting impaired vestibular perception. Tilt discrimination in patients, moreover, did not improve as much as in hS in conditions where both SCC and OT information was available compared to conditions where only SCC or OT cues were activated. The latter provides evidence that tilt misperception in PD most likely results from an integration failure of vestibular signals.

  2. A blended wing body airplane with a close-coupled, tilting tail

    Science.gov (United States)

    Nasir, R. E. M.; Mazlan, N. S. C.; Ali, Z. M.; Wisnoe, W.; Kuntjoro, W.

    2016-10-01

    This paper highlights a novel approach to stabilizing and controlling pitch and yaw motion via a set of horizontal tail that can act as elevator and rudder. The tail is incorporated into a new design of blended wing body (BWB) aircraft, known as Baseline-V, located just aft of the trailing edge of its inboard wing. The proposed close-coupled tail is equipped with elevators that deflect in unison, and can tilt - an unusual means of tilting where if starboard side is tilted downward at k degree, and then the portside must be tilted upward at k degree too. A wind tunnel experiment is conducted to investigate aerodynamics and static stability of Baseline-V BWB aircraft. The model is being tested at actual flight speed of 15 m/s (54 km/h) with varying angle of attack for five elevator angle cases at zero tilt angle and varying sideslip angle for four tilt angle cases at one fixed elevator angle. The result shows that the aircraft's highest lift-to-drag ratio is 32. It is also found that Baseline-V is statically stable in pitch and yaw but has no clear indication in terms of roll stability.

  3. Estimation of pelvic tilt on anteroposterior X-rays - a comparison of six parameters

    Energy Technology Data Exchange (ETDEWEB)

    Tannast, M. [University of Bern, Department of Orthopedic Surgery, Inselspital, Bern (Switzerland); New England Baptist Hospital, Center for Computer Assisted and Reconstructive Surgery, Boston, MA (United States); Tufts University School of Medicine, Boston, MA (United States); Harvard Medical School, Boston, MA (United States); Murphy, S.B. [New England Baptist Hospital, Center for Computer Assisted and Reconstructive Surgery, Boston, MA (United States); Tufts University School of Medicine, Boston, MA (United States); Harvard Medical School, Boston, MA (United States); Langlotz, F. [University of Bern, MEM Research Center for Orthopaedic Surgery, Institute for Surgical Technologies and Biomechanics, Bern (Switzerland); Anderson, S.E. [University of Bern, Department of Diagnostic Interventional and Pediatric Radiology, Bern (Switzerland); Siebenrock, K.A. [University of Bern, Department of Orthopedic Surgery, Inselspital, Bern (Switzerland)

    2006-03-15

    To compare six different parameters described in literature for estimation of pelvic tilt on an anteroposterior pelvic radiograph and to create a simple nomogram for tilt correction of prosthetic cup version in total hip arthroplasty. Simultaneous anteroposterior and lateral pelvic radiographs are taken routinely in our institution and were analyzed prospectively. The different parameters (including three distances and three ratios) were measured and compared to the actual pelvic tilt on the lateral radiograph using simple linear regression analysis. One hundred and four consecutive patients (41 men, 63 women with a mean age of 31.7 years, SD 9.2 years, range 15.7-59.1 years) were studied. The strongest correlation between pelvic tilt and one of the six parameters for both men and women was the distance between the upper border of the symphysis and the sacrococcygeal joint. The correlation coefficient was 0.68 for men (P<0.001) and 0.61 for women (P<0.001). Based on this linear correlation, a nomogram was created that enables fast, tilt-corrected cup version measurements in clinical routine use. This simple method for correcting variations in pelvic tilt on plain radiographs can potentially improve the radiologist's ability to diagnose and interpret malformations of the acetabulum (particularly acetabular retroversion and excessive acetabular overcoverage) and post-operative orientation of the prosthetic acetabulum. (orig.)

  4. Roll tilt psychophysics in rhesus monkeys during vestibular and visual stimulation.

    Science.gov (United States)

    Lewis, Richard F; Haburcakova, Csilla; Merfeld, Daniel M

    2008-07-01

    How does the brain calculate the spatial orientation of the head relative to gravity? Psychophysical measurements are critical to investigate this question, but such measurements have been limited to humans. In non-human primates, behavioral measures have focused on vestibular-mediated eye movements, which do not reflect percepts of head orientation. We have therefore developed a method to measure tilt perception in monkeys, derived from the subjective visual vertical (SVV) task. Two rhesus monkeys were trained to align a light bar parallel to gravity and performed this task during roll tilts, centrifugation, and roll optokinetic stimulation. The monkeys accurately aligned the light bar with gravity during static roll tilts but also demonstrated small orientation-dependent misperceptions of the tilt angle analogous to those measured in humans. When the gravito-inertial force (GIF) rotated dynamically in the roll plane, SVV responses remained closely aligned with the GIF during roll tilt of the head (coplanar canal rotational cues present), lagged slightly behind the GIF during variable-radius centrifugation (no canal cues present), and shifted gradually during fixed-radius centrifugation (orthogonal yaw canal cues present). SVV responses also deviated away from the earth-vertical during roll optokinetic stimulation. These results demonstrate that rotational cues derived from the semicircular canals and visual system have prominent effects on psychophysical measurements of roll tilt in rhesus monkeys and therefore suggest that a central synthesis of graviceptive and rotational cues contributes to percepts of head orientation relative to gravity in non-human primates.

  5. Thermal and tilt effects on bearing characteristics of hydrostatic oil pad in rotary table

    Institute of Scientific and Technical Information of China (English)

    刘志峰; 湛承鹏; 程强; 赵永胜; 李小燕; 王义达

    2016-01-01

    Hydrostatic pads are key components of a constant flow compensation hydrostatic rotary table. The tilt and thermal effects due to the partial load, the manufacturing errors and the friction must be considered. However, designers are more likely inclined to ignore these effects. In this work, the coupled characteristics of the tilt and thermal effects are studied. A coupled mathematical model to calculate the bearing properties of the pads is built. This model takes into consideration of tilt and thermal effects and is used to solve the flow problem by the finite difference method. The characteristics of the oil pad, including, the recess pressures, the load carrying capacity and the damping coefficients, are obtained and the tilt and thermal effects are analyzed. It is observed that the tilt has a tremendous impact on the bearing characteristics of the hydrostatic pad. The recess pressure, the load carrying capacity and the stiffness are reduced by 50% and the pressure distribution and the temperature distribution of the oil film also change significantly. When the pads work under a tilt operation, a larger land width is better for its bearing properties. It is also observed that the thermal effect is significant and cannot be ignored.

  6. Fast and automatic identification of particle tilt pairs based on Delaunay triangulation.

    Science.gov (United States)

    Vilas, J L; Navas, J; Gómez-Blanco, J; de la Rosa-Trevín, J M; Melero, R; Peschiera, I; Ferlenghi, I; Cuenca, J; Marabini, R; Carazo, J M; Vargas, J; Sorzano, C O S

    2016-12-01

    Random conical tilt (RCT) and orthogonal tilt reconstruction (OTR) are two remarkable methods for reconstructing the three-dimensional structure of macromolecules at low resolution. These techniques use two images at two different sample tilts. One of the most demanding steps in these methods at the image processing level is to identify corresponding particles on both micrographs, and manual or semiautomatic matching methods are usually used. Here we present an approach to solve this bottleneck with a fully automatic method for assigning particle tilt pairs. This new algorithm behaves correctly with a variety of samples, covering the range from small to large macromolecules and from sparse to densely populated fields of view. It is also more rapid than previous approaches. The roots of the method lie in a Delaunay triangulation of the set of independently picked coordinates on both the untilted and tilted micrographs. These triangulations are then used to search an affine transformation between the untilted and tilted triangles. The affine transformation that maximizes the number of correspondences between the two micrographs defines the coordinate matching. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Tilted wheel satellite attitude control with air-bearing table experimental results

    Science.gov (United States)

    Inumoh, Lawrence O.; Forshaw, Jason L.; Horri, Nadjim M.

    2015-12-01

    Gyroscopic actuators for satellite control have attracted significant research interest over the years, but their viability for the control of small satellites has only recently started to become clear. Research on variable speed gyroscopic actuators has long been focused on single gimbal actuators; double gimbal actuators typically operate at constant wheel spin rate and allow tilt angle ranges far larger than the ranges needed to operate most satellite missions. This research examines a tilted wheel, a newly proposed type of inertial actuator that can generate torques in all three principal axes of a rigid satellite using a spinning wheel and a double tilt mechanism. The tilt mechanism tilts the angular momentum vector about two axes providing two degree of freedom control, while variation of the wheel speed provides the third. The equations of motion of the system lead to a singularity-free system during nominal operation avoiding the need for complex steering logic. This paper describes the hardware design of the tilted wheel and the experimental setup behind both standalone and spherical air-bearing tables used to test it. Experimental results from the air bearing table are provided with the results depicting the high performance capabilities of the proposed actuator in torque generation.

  8. Numerical Simulations of Naturally Tilted, Retrogradely Precessing, Nodal Superhumping Accretion Disks

    CERN Document Server

    Montgomery, M M

    2012-01-01

    Accretion disks around black hole, neutron star, and white dwarf systems are thought to sometimes tilt, retrogradely precess, and produce hump-shaped modulations in light curves that have a period shorter than the orbital period. Although artificially rotating numerically simulated accretion disks out of the orbital plane and around the line of nodes generates these short-period superhumps and retrograde precession of the disk, no numerical code to date has been shown to produce a disk tilt naturally. In this work, we report the first naturally tilted disk in non-magnetic Cataclysmic Variables (CVs) using 3D Smoothed Particle Hydrodynamics (SPH). Our simulations show that after many hundreds of orbital periods, the disk has tilted on its own and this disk tilt is without the aid of radiation sources or magnetic fields. As the system orbits, the accretion stream strikes the bright spot (which is on the rim of the tilted disk) and flows over and under the disk on different flow paths. These different flow paths...

  9. Does an Average White Dwarf Have Enough Mass to Prevent an Accretion Disk Tilt?

    CERN Document Server

    Montgomery, M M

    2010-01-01

    In a recent publication, we introduce the lift force as a common source to accretion disk tilt that is likely relevant to accretion disk systems. Lift is generated by slightly different supersonic gas stream speeds flowing over and under the disk at the bright spot. In this conference proceeding, we focus on whether the average white dwarf has enough mass to prevent a disk tilt in non-magnetic Cataclysmic Variables (CVs) with accretion disks. Assuming a white dwarf mass of 0.6M$_{\\odot}$ and a disk mass of 10$^{-11}$M$_{\\odot}$, we vary the secondary mass to establish theoretical minimum mass transfer rates needed to induce and maintain a disk tilt of four degrees around the line of nodes. For mass ratios in the range \\( (0.13 \\le q=M_{2}M^{-1} \\le 0.45) \\), we confirm that the secondary mass does not contribute significantly to disk tilt. We also confirm that the average white dwarf does not have enough mass to prevent a disk tilt. We find that disk tilt may be likely in low mass transfer rate systems such a...

  10. Wind-tunnel investigation of the flow correction for a model-mounted angle of attack sensor at angles of attack from -10 deg to 110 deg. [Langley 12-foot low speed wind tunnel test

    Science.gov (United States)

    Moul, T. M.

    1979-01-01

    A preliminary wind tunnel investigation was undertaken to determine the flow correction for a vane angle of attack sensor over an angle of attack range from -10 deg to 110 deg. The sensor was mounted ahead of the wing on a 1/5 scale model of a general aviation airplane. It was shown that the flow correction was substantial, reaching about 15 deg at an angle of attack of 90 deg. The flow correction was found to increase as the sensor was moved closer to the wing or closer to the fuselage. The experimentally determined slope of the flow correction versus the measured angle of attack below the stall angle of attack agreed closely with the slope of flight data from a similar full scale airplane.

  11. Lampi di possibili tempeste. Arte e letteratura nel Foucault degli anni Settanta.

    Directory of Open Access Journals (Sweden)

    Diego Melegari

    2012-12-01

    Full Text Available Dopo avere rivestito un ruolo fondamentale negli scritti archeologici degli anni Sessanta, i riferimenti a pittura e letteratura sembrano scomparire dalla riflessione foucaultiana. Si tratta, in realtà, di uno slittamento dalle opere maggiori a brevi interventi in cui ad emergere è soprattutto il coinvolgimento soggettivo di Foucault. Questo passaggio, però, non è che un aspetto di una radicale riformulazione della funzione storico-ontologica precedentemente attribuita a letteratura e arte in favore di forme di esperienza non-strategica, dunque irriducibile al nesso potere-resistenza, e allo stesso tempo riattivabile come critica, anche politica, nel rapporto tra tempo storico e trasformazione della soggettività.

  12. Il problema dei futuri contingenti e la semantica relativista degli enunciati al futuro

    Directory of Open Access Journals (Sweden)

    Diana Mazzarella

    2011-11-01

    Full Text Available L'articolo si propone tre obiettivi. In primo luogo, introdurre al problema dei futuri contingenti, evidenziando i limiti di un'analisi semantica standard degli enunciati al futuro. In secondo luogo, presentare le strategie di implementazione della semantica standard finalizzate ad un approccio semantico di tipo relativistico, distinguendo tra relativismo moderato e relativismo radicale. In terzo luogo, presentare il tentativo di risoluzione del problema in questione attraverso l'adozione di una prospettiva semantica relativista, con esplicito riferimento alle riflessioni di MacFarlane.

  13. L’avventura del teatro granducale degli Uffizi (1586-1637

    Directory of Open Access Journals (Sweden)

    Anna Maria Testaverde

    2016-06-01

    Full Text Available The essay reconstructs the chronological details of the construction and disposal of the Teatro degli Uffizi. An extensive unpublished documentation, and a newly discovered plan of the theatre in the Archivio di Stato di Modena, bring to light hitherto unknown persons and situations. The study anticipates reflections and proposals for a structural solution that would modify the model proposed in 1975 by Ludovico Zorzi. As a foundation of these new hypotheses, the essay offers a re-reading of the Vitruvius’s theories on which the florentine highly specialised technical skills were based on.

  14. “Il coraggio di essere giovani”: un progetto sulla Fgci di Modena degli anni Ottanta

    Directory of Open Access Journals (Sweden)

    Claudia Capelli

    2015-12-01

    Full Text Available L’Istituto Storico di Modena promuove una ricerca sulla Fgci di Modena degli anni Ottanta con l'obiettivo di cominciare a riflettere sul decennio conclusivo della storia del Pci, un periodo di crisi profonda della cultura politica comunista che la storiografia non ha ancora affrontato in modo sistematico. Il caso modenese permette di osservare alcuni importanti elementi dell'esperienza della Fgci “rifondata”, come il nuovo approccio alla comunicazione politica e il rapporto con i movimenti sociali.

  15. Fattori di crescita e recettori tirosin chinasici nelle neoplasie e displasie degli animali domestici

    OpenAIRE

    Muscatello, Luisa Vera

    2016-01-01

    La perdita della comunicazione cellulare può portare ad una crescita deregolata e dunque alla trasformazione neoplastica. Gli scopi dello studio di dottorato sono stati di individuare il rapporto funzionale di alcuni fattori di crescita (FC) e dei loro recettori (RTC) in tipi di neoplasie e displasie degli animali domestici, quali: 1. Amplificazione del proto-oncogene ERBB2 e sovra-espressione del RTC erb-b2. in tumori mammari della gatta. 2. Espressione di erb-b2, di recettori ormonal...

  16. A catalogue of galaxies behind the southern Milky Way. - II. The Crux and Great Attractor regions (l = 289deg - 338deg)

    CERN Document Server

    Woudt, P A; Woudt, Patrick A.; Kraan-Korteweg, Renee C.

    2001-01-01

    In this second paper of the catalogue series of galaxies behind the southern Milky Way, we report on the deep optical galaxy search in the Crux region (289deg = 0.2 arcmin were identified in this ~850 square degree area: 3759 galaxies in the Crux region and 4423 galaxies in the Great Attractor region. Of the 8182 galaxies, 229 (2.8%) were catalogued before in the optical (3 in radio) and 251 galaxies have a reliable (159), or likely (92) cross-identification in the IRAS Point Source Catalogue (3.1%). A number of prominent overdensities and filaments of galaxies are identified. They are not correlated with the Galactic foreground extinction and hence indicative of extragalactic large-scale structures. Redshifts obtained at the South African Astronomical Observatory (SAAO) for 518 of the newly catalogued galaxies in the Crux and Great Attractor regions (Fairall et al. 1998; Woudt et al. 1999) confirm distinct voids and clusters in the area here surveyed. With this optical galaxy search, we have reduced the widt...

  17. Ultrasound as a Noninvasive Method to Assess Changes of Intracranial Volume and Pressure During Simulated Microgravity

    Science.gov (United States)

    Murthy, G.; Yost, W. T.; Ballard, R. E.; Watenpaugh, D. E.; Kawai, Y.; Hargens, A. R.

    1994-01-01

    Headaches are commonly experienced by astronauts in microgravity and by subjects undergoing head-down tilt (simulated microgravity on Earth). Exposure to microgravity probably elevates blood pressure and flow in the head which may increase intracranial volume (ICV) and pressure (ICP) and in turn cause headache. Due to the slightly compliant nature of the cranial vault and the encasement of brain and its vasculature within this vault, any increase of ICV will increase ICP and slightly distend the cranium. Previous studies document perivascular edema and increased ICP in rhesus monkeys during head-down tilt. Elevated ICP has also been reported in humans during head-down tilt. ICP measurements in healthy humans are rare because of the invasiveness of currently-available measurement techniques. Therefore, we proposed a noninvasive ultrasound technique to assess changes of ICV and JCP. The ultrasound principle is based on compliance of the cranial vault. A 450 kHz ultrasound stimulus is transmitted through the cranium by a transducer every 7.5-10 msec. The ultrasound wave enters the brain tissue, reflects off the opposite side of the cranium and is received by the same transducer. The detected wave is compared for phase quadrature (90 deg.to transmitted wave). Because the electronic circuitry of the device maintains a 90 deg. phase (phi), any alterations in the detected wave caused by an increase of ICV and ICP will be reflected as a change in the wave frequency. Phase shift is directly proportional to path length of the wave, DELTA x, which is expressed as DELTA x = phi lambda/2 pi where lambda is wavelength. Elevated ICV and ICP expand the cranial vault and increase path length of the wave (a measure of intracranial distance). Increased path length equals reduced frequency of the detected wave. Reduced frequency is then related to elevated ICP. This technique has potential uses for ICP studies of astronauts in space and head trauma patients on Earth.

  18. Bielschowsky head-tilt test-I. Ocular counterrolling and Bielschowsky head-tilt test in 23 cases of superior oblique palsy

    NARCIS (Netherlands)

    H.J. Simonsz (Huib); R.A. Crone; J.W.C. Meer (Jolanda); C.F. Merckel-Timmer; A.M. van Mourik-Noordenbos

    1985-01-01

    textabstractWe have measured the amplitude of ocular counterrolling (OCR) and the change in vertical deviation in the Bielschowsky head-tilt test (BHT) in 23 cases of unilateral superior oblique palsy. OCR was measured with a photographical method, using limbal, conjunctival vessels as landmarks.

  19. Bielschowsky head-tilt test-I. Ocular counterrolling and Bielschowsky head-tilt test in 23 cases of superior oblique palsy

    NARCIS (Netherlands)

    H.J. Simonsz (Huib); R.A. Crone; J.W.C. Meer (Jolanda); C.F. Merckel-Timmer; A.M. van Mourik-Noordenbos

    1985-01-01

    textabstractWe have measured the amplitude of ocular counterrolling (OCR) and the change in vertical deviation in the Bielschowsky head-tilt test (BHT) in 23 cases of unilateral superior oblique palsy. OCR was measured with a photographical method, using limbal, conjunctival vessels as landmarks. Av

  20. Design and Analysis of Delta Wing Tilt Rotor UAV

    Directory of Open Access Journals (Sweden)

    S.Ravikanth

    2015-07-01

    Full Text Available A tilt rotor is an aircraft of a special kind, which possesses the characteristics of a helicopter and a fixed-wing airplane. However, there are a great number of important technical problems waiting for settlements. Of them, the flight control system might be a critical one. A tiltrotor aircraft comprising a pair of contra-rotating co-axial tiltable rotors on the longitudinal center line of the aircraft. The rotors may be tiltable sequentially and independently. They may be moveable between a lift position and a flight position in front of or behind the fuselage.In this paper we present a project aimed for the designing of a small scale Unmanned Aerial Vehicle (UAV with Tiltrotor configuration (that uses two rotating rotors. he current paper describes the adopted design methodology, the mathematical and computational models created to represent the UAV, the physical components that constitute the UAV, and the results obtained so far. An unmanned aerial vehicle (UAV, also known as a remotely piloted aircraft (RPA or unmanned aircraft, is a machine which functions either by the remote control of a navigator or pilot or autonomously. A UAV is defined as a powered, aerial vehicle that does not carry a human operator, uses aerodynamic forces to provide vehicle lift, can fly autonomously or be piloted remotely, can be expendable or recoverable, and can carry payload.India‘s requirement of these unmanned aerial vehicles (UAV has become prior need for fighting in the northeast, against threat of terrorism, tension along the Pakistan border and its emerging role as a regional naval power and subsequent need for surveillance. The military wants to acquire at least 1,500 unmanned systems in the next 3-4 years, ranging from man-portable drones to high-altitude, long-endurance (HALE vehicles.Indian military is using Israeli-built UAVs such as the Heron, Searcher Mk II and Harop from Israel Aerospace Industries (IAI. Till date India has mostly deployed