Stress Intensity Factors of Slanted Cracks in Bi-Material Plates

Science.gov (United States)

Ismail, Al Emran; Azhar Kamarudin, Kamarul; Nor, Nik Hisyamudin Muhd

2017-10-01

In this study, the stress intensity factors (SIF) of slanted cracks in bi-material plates subjected to mode I loading is numerically solved. Based on the literature survey, tremendous amount of research works are available studying the normal cracks in both similar and dissimilar plates. However, lack of SIF behavior for slanted cracks especially when it is embedded in bi-material plates. The slanted cracks are then modelled numerically using ANSYS finite element program. Two plates of different in mechanical properties are firmly bonded obliquely and then slanted edge cracks are introduced at the lower inclined edge. Isoparametric singular element is used to model the crack tip and the SIF is determined which is based on the domain integral method. Three mechanical mismatched and four slanted angles are used to model the cracks. According to the present results, the effects of mechanical mismatch on the SIF for normal cracks are not significant. However, it is played an important role when slanted angles are introduced. It is suggested that higher SIF can be obtained when the cracks are inclined comparing with the normal cracks. Consequently, accelerating the crack growth at the interface between two distinct materials.

The caudal septum replacement graft.

Science.gov (United States)

Foda, Hossam M T

2008-01-01

To describe a technique for reconstructing the lost tip support in cases involving caudal septal and premaxillary deficiencies. The study included 120 patients with aesthetic and functional nasal problems resulting from the loss of caudal septal and premaxillary support. An external rhinoplasty approach was performed to reconstruct the lost support using a cartilaginous caudal septum replacement graft and premaxillary augmentation with Mersilene mesh. The majority of cases (75%) involved revisions in patients who had previously undergone 1 or more nasal surgical procedures. A caudal septum replacement graft was combined with premaxillary augmentation in 93 patients (77.5%). The mean follow-up period was 3 years (range, 1-12 years). The technique succeeded in correcting the external nasal deformities in all patients and resulted in a significant improvement in breathing in 74 patients (86%) with preoperative nasal obstruction. There were no cases of infection, displacement, or extrusion. The caudal septum replacement graft proved to be very effective in restoring the lost tip support in patients with caudal septal deficiency. Combining the graft with premaxillary augmentation using Mersilene mesh helped increase support and stability over long-term follow-up.

Five cases of caudal regression with an aberrant abdominal umbilical artery: Further support for a caudal regression-sirenomelia spectrum.

Science.gov (United States)

Duesterhoeft, Sara M; Ernst, Linda M; Siebert, Joseph R; Kapur, Raj P

2007-12-15

Sirenomelia and caudal regression have sparked centuries of interest and recent debate regarding their classification and pathogenetic relationship. Specific anomalies are common to both conditions, but aside from fusion of the lower extremities, an aberrant abdominal umbilical artery ("persistent vitelline artery") has been invoked as the chief anatomic finding that distinguishes sirenomelia from caudal regression. This observation is important from a pathogenetic viewpoint, in that diversion of blood away from the caudal portion of the embryo through the abdominal umbilical artery ("vascular steal") has been proposed as the primary mechanism leading to sirenomelia. In contrast, caudal regression is hypothesized to arise from primary deficiency of caudal mesoderm. We present five cases of caudal regression that exhibit an aberrant abdominal umbilical artery similar to that typically associated with sirenomelia. Review of the literature identified four similar cases. Collectively, the series lends support for a caudal regression-sirenomelia spectrum with a common pathogenetic basis and suggests that abnormal umbilical arterial anatomy may be the consequence, rather than the cause, of deficient caudal mesoderm. (c) 2007 Wiley-Liss, Inc.

Caudal bupivacaine supplemented with caudal or intravenous clonidine in children undergoing hypospadias repair: a double-blind study

DEFF Research Database (Denmark)

Hansen, T G; Henneberg, S W; Walther-Larsen, S

2004-01-01

Clonidine is used increasingly in paediatric anaesthetic practice to prolong the duration of action of caudal block with a local anaesthetic agent. Which route of administration of clonidine is the most beneficial remains unknown. We compared the effects of caudal and i.v. clonidine on postoperat...... on postoperative analgesia produced by caudal bupivacaine after hypospadias repair....

Caudal regression syndrome : a case report

International Nuclear Information System (INIS)

Lee, Eun Joo; Kim, Hi Hye; Kim, Hyung Sik; Park, So Young; Han, Hye Young; Lee, Kwang Hun

1998-01-01

Caudal regression syndrome is a rare congenital anomaly, which results from a developmental failure of the caudal mesoderm during the fetal period. We present a case of caudal regression syndrome composed of a spectrum of anomalies including sirenomelia, dysplasia of the lower lumbar vertebrae, sacrum, coccyx and pelvic bones,genitourinary and anorectal anomalies, and dysplasia of the lung, as seen during infantography and MR imaging

Caudal regression syndrome : a case report

Energy Technology Data Exchange (ETDEWEB)

Lee, Eun Joo; Kim, Hi Hye; Kim, Hyung Sik; Park, So Young; Han, Hye Young; Lee, Kwang Hun [Chungang Gil Hospital, Incheon (Korea, Republic of)

1998-07-01

Caudal regression syndrome is a rare congenital anomaly, which results from a developmental failure of the caudal mesoderm during the fetal period. We present a case of caudal regression syndrome composed of a spectrum of anomalies including sirenomelia, dysplasia of the lower lumbar vertebrae, sacrum, coccyx and pelvic bones,genitourinary and anorectal anomalies, and dysplasia of the lung, as seen during infantography and MR imaging.

T-junctions and perceived slant of partially occluded surfaces.

Science.gov (United States)

Grove, Philip M; Ono, Hiroshi; Kaneko, Hirohiko

2003-01-01

Häkkinen and Nyman (1997 Perception 26 29-38) reported that perceived slant is reduced when occlusion is a possible interpretation for the visual system. We present data from three experiments that confirm and expand on their finding. Our stimuli consisted of four types of stereograms depicting white central rectangles flanked on either side by two grey rectangles. The central white rectangles varied in height, thus manipulating the polarity of the T-junction information between the central and flanking rectangles. Perceived slant was smallest or not apparent when T-junction information indicated the central rectangles were nearer than the flanking rectangles and greatest when T-junction information indicated a farther central rectangle. Slant estimates for a stimulus containing a subjective pacmen-induced central rectangle were biased towards a depth step when an occlusion interpretation was possible.

Thermal Behaviour of Beams with Slant End-Plate Connection Subjected to Nonsymmetric Gravity Load

Directory of Open Access Journals (Sweden)

Farshad Zahmatkesh

2014-01-01

Full Text Available Research on the steel structures with confining of axial expansion in fixed beams has been quite intensive in the past decade. It is well established that the thermal behaviour has a key influence on steel structural behaviours. This paper describes mechanical behaviour of beams with bolted slant end-plate connection with nonsymmetric gravity load, subjected to temperature increase. Furthermore, the performance of slant connections of beams in steel moment frame structures in the elastic field is investigated. The proposed model proved that this flexible connection system could successfully decrease the extra thermal induced axial force by both of the friction force dissipation among two faces of slant connection and a small upward movement on the slant plane. The applicability of primary assumption is illustrated. The results from the proposed model are examined within various slant angles, thermal and friction factors. It can be concluded that higher thermal conditions are tolerable when slanting connection is used.

Caudal ropivacaine in infants

DEFF Research Database (Denmark)

Hansen, Tom Giedsing; Ilett, K F; Reid, C

2001-01-01

Ropivacaine is a new long-acting amino-amide local anesthetic. However, there are no data on its use in infants. In the current study, the authors investigated the pharmacokinetics of caudal ropivacaine in 30 infants younger than 12 months.......Ropivacaine is a new long-acting amino-amide local anesthetic. However, there are no data on its use in infants. In the current study, the authors investigated the pharmacokinetics of caudal ropivacaine in 30 infants younger than 12 months....

Genetics Home Reference: caudal regression syndrome

Science.gov (United States)

... umbilical artery: Further support for a caudal regression-sirenomelia spectrum. Am J Med Genet A. 2007 Dec ... AK, Dickinson JE, Bower C. Caudal dysgenesis and sirenomelia-single centre experience suggests common pathogenic basis. Am ...

IMPROVEMENT IN HANDWRITTEN NUMERAL STRING RECOGNITION BY SLANT NORMALIZATION AND CONTEXTUAL INFORMATION

NARCIS (Netherlands)

Britto jr., A. de S.; Sabourin, R.; Lethelier, E.; Bortolozzi, F.; Suen, C.Y.

2004-01-01

This work describes a way of enhancing handwritten numeral string recognition by considering slant normalization and contextual information to train an implicit segmentation­based system. A word slant normalization method is modified in order to improve the results for handwritten numeral strings.

Gold dimer nanoantenna with slanted gap for tunable LSPR and improved SERS

KAUST Repository

Kessentini, Sameh

2014-02-13

We focus on improving the surface-enhanced Raman scattering (SERS) of dimer nanoantenna by tailoring the shape of the coupled nanoantennas extremities from rounded to straight or slanted ones. A numerical model based on the discrete dipole approximation method-taking into account periodicity, adhesion layer, and roughness-is first validated by comparison with localized surface plasmon resonance (LSPR) and SERS experiments on round-edged dimer nanoantennas and then used to investigate the effect of the straight or slanted gap in the dimer antenna. Simulations show that both LSPR and SERS can be tuned by changing the gap slanting angle. The SERS enhancement factor can also be improved by 2 orders of magnitude compared to the one reached using a rounded gap. Therefore, the slanting angle can be used as a new control parameter in the design of SERS substrates to guarantee stronger field confinement and higher sensitivity, especially as its feasibility is demonstrated. © 2014 American Chemical Society.

Gold dimer nanoantenna with slanted gap for tunable LSPR and improved SERS

KAUST Repository

Kessentini, Sameh; Barchiesi, Dominique; D'Andrea, Cristiano; Toma, Andrea; Guillot, Nicolas; Di Fabrizio, Enzo M.; Fazio, Barbara; Maragó , Onofrio M.; Gucciardi, Pietro Giuseppe; Lamy De La Chapelle, Marc L.

2014-01-01

We focus on improving the surface-enhanced Raman scattering (SERS) of dimer nanoantenna by tailoring the shape of the coupled nanoantennas extremities from rounded to straight or slanted ones. A numerical model based on the discrete dipole approximation method-taking into account periodicity, adhesion layer, and roughness-is first validated by comparison with localized surface plasmon resonance (LSPR) and SERS experiments on round-edged dimer nanoantennas and then used to investigate the effect of the straight or slanted gap in the dimer antenna. Simulations show that both LSPR and SERS can be tuned by changing the gap slanting angle. The SERS enhancement factor can also be improved by 2 orders of magnitude compared to the one reached using a rounded gap. Therefore, the slanting angle can be used as a new control parameter in the design of SERS substrates to guarantee stronger field confinement and higher sensitivity, especially as its feasibility is demonstrated. © 2014 American Chemical Society.

Ontogenetic scaling of caudal fin shape in Squalus acanthias (Chondrichthyes, Elasmobranchii): a geometric morphometric analysis with implications for caudal fin functional morphology.

Science.gov (United States)

Reiss, Katie L; Bonnan, Matthew F

2010-07-01

The shark heterocercal caudal fin and its contribution to locomotion are of interest to biologists and paleontologists. Current hydrodynamic data show that the stiff dorsal lobe leads the ventral lobe, both lobes of the tail are synchronized during propulsion, and tail shape reflects its overall locomotor function. Given the difficulties surrounding the analysis of shark caudal fins in vivo, little is known about changes in tail shape related to ontogeny and sex in sharks. A quantifiable analysis of caudal fin shape may provide an acceptable proxy for inferring gross functional morphology where direct testing is difficult or impossible. We examined ontogenetic and sex-related shape changes in the caudal fins of 115 Squalus acanthias museum specimens, to test the hypothesis that significant shape changes in the caudal fin shape occur with increasing size and between the sexes. Using linear and geometric morphometrics, we examined caudal shape changes within the context of current hydrodynamic models. We found no statistically significant linear or shape difference between sexes, and near-isometric scaling trends for caudal dimensions. These results suggest that lift and thrust increase linearly with size and caudal span. Thin-plate splines results showed a significant allometric shape change associated with size and caudal span: the dorsal lobe elongates and narrows, whereas the ventral lobe broadens and expands ventrally. Our data suggest a combination of caudal fin morphology with other body morphology aspects, would refine, and better elucidate the hydrodynamic factors (if any) that underlie the significant shape changes we report here for S. acanthias.

A long slanted transseptal accessory pathway

Directory of Open Access Journals (Sweden)

Hui-Min Wang

2011-05-01

Full Text Available A 63-year-old male with Wolff-Parkinson-White syndrome was admitted for ablation of accessory pathway. Intracardiac electrogram revealed a left-side accessory pathway during tachycardia, which was successfully ablated from the right posterior tricuspid annulus because of a long slanted transseptal accessory pathway (2.2 cm.

On site experiments of the slanted soil treatment systems for domestic gray water.

Science.gov (United States)

Itayama, Tomoaki; Kiji, Masato; Suetsugu, Aya; Tanaka, Nobuyuki; Saito, Takeshi; Iwami, Norio; Mizuochi, Motoyuki; Inamori, Yuhei

2006-01-01

In order to make a breakthrough for the acute problem of water shortage in the world, the key words "decentralization and re-use" are very important for new sustainable sanitation systems that will be developed. Therefore, we focused on a new treatments system called "a slanted soil treatment system" which combines a biotoilet system with a domestic grey water treatment system. Because this system is a low cost and compact system, the system can be easily introduced to homes in urban areas or in the suburbs of cities in many developing countries. In this study, we performed on site experiments carried out on Shikoku Island, Japan, for several years. We obtained the following results. The slanted soil treatment system could remove organic pollutants and total nitrogen and total phosphorus in grey water effectively. Furthermore, the system performance became high in the case of the high concentration of the influent water. The nitrification reaction and denitrification reaction were speculated to exist due to aerobic zones and anaerobic zones present in the slanted soil treatment system. The slanted soil treatment system could perform for approximately 3 years with zero maintenance. The plug flow model of 1st order reaction kinetics could describe the reaction in the slanted soil treatment system. However, it is necessary to improve the system to maintain the performance in all seasons.

Traction suture modification to tongue-in-groove caudal septoplasty.

Science.gov (United States)

Indeyeva, Y A; Lee, T S; Gordin, E; Chan, D; Ducic, Y

2018-02-01

Caudal septal deviation leads to unfavorable esthetic as well as functional effects on the nasal airway. A modification to the tongue-in-groove (TIG) technique to correct these caudal septal deformities is described. With placement of a temporary suspension suture to the caudal septum, manual traction is applied, assuring that the caudal septum remains in the midline position while it is being secured with multiple through-and-through, trans-columellar and trans-septal sutures. From 2003 to 2016, 148 patients underwent endonasal septoplasty using this modified technique, with excellent functional and cosmetic outcomes and a revision rate of 1.4%. This modified TIG technique replaces the periosteal suture that secures the caudal septum to the midline nasal crest in the original TIG technique. This simplifies the procedure and minimizes the risk of securing the caudal septum off-midline when used in endonasal septoplasty. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Plastic Limit Loads for Slanted Circumferential Through-Wall Cracked Pipes Using 3D Finite-Element Limit Analyses

International Nuclear Information System (INIS)

Jang, Hyun Min; Cho, Doo Ho; Kim, Young Jin; Huh, Nam Su; Shim, Do Jun; Choi, Young Hwan; Park, Jung Soon

2011-01-01

On the basis of detailed 3D finite-element (FE) limit analyses, the plastic limit load solutions for pipes with slanted circumferential through-wall cracks (TWCs) subjected to axial tension, global bending, and internal pressure are reported. The FE model and analysis procedure employed in the present numerical study were validated by comparing the present FE results with existing solutions for plastic limit loads of pipes with idealized TWCs. For the quantification of the effect of slanted crack on plastic limit load, slant correction factors for calculating the plastic limit loads of pipes with slanted TWCs from pipes with idealized TWCs are newly proposed from extensive 3D FE calculations. These slant-correction factors are presented in tabulated form for practical ranges of geometry and for each set of loading conditions

High-aspect-ratio microstructures with versatile slanting angles on silicon by uniform metal-assisted chemical etching

Science.gov (United States)

Li, Liyi; Zhang, Cheng; Tuan, Chia-Chi; Chen, Yun; Wong, C.-P.

2018-05-01

High-aspect-ratio (HAR) microstructures on silicon (Si) play key roles in photonics and electromechanical devices. However, it has been challenging to fabricate HAR microstructures with slanting profiles. Here we report successful fabrication of uniform HAR microstructures with controllable slanting angles on (1 0 0)-Si by slanted uniform metal-assisted chemical etching (SUMaCE). The trenches have width of 2 µm, aspect ratio greater than 20:1 and high geometric uniformity. The slanting angles can be adjusted between 2-70° with respect to the Si surface normal. The results support a fundamental hypothesis that under the UMaCE condition, the preferred etching direction is along the normal of the thin film catalysts, regardless of the relative orientation of the catalyst to Si substrates or the crystalline orientation of the substrates. The SUMaCE method paves the way to HAR 3D microfabrication with arbitrary slanting profiles inside Si.

Binocular perception of slant about oblique axes relative to a visual frame of reference

NARCIS (Netherlands)

Ee, R. van; Erkelens, Casper J.

1995-01-01

From the literature it is known that the processing of disparity for slant is different in the presence and in the absence of a visual frame of reference. We elaborate the experimental finding that vertical disparity is not processed for slant perception in the presence of a visual reference. This

Comparison between the intravenous and caudal routes of sufentanil in children undergoing orchidopexy and further evaluation of the association of caudal adrenaline and neostigmine

Directory of Open Access Journals (Sweden)

Gabriela Rocha Lauretti

2014-01-01

Full Text Available Background: The aim of this study was to compare the intravenous (IV and caudal routes of administration of sufentanil for children undergoing orchidopexy and also to evaluate the effects on addition of caudal adrenaline and neostigmine. Materials and Methods: Sixty patients scheduled for orchidopexy were divided into the following groups: 1 Group IVSu received IV 0.5 μg/kg sufentanil and caudal saline; 2 Group CSu received caudal 0.5 μg/kg sufentanil and IV saline; 3 Group CSuAdr received caudal sufentanil plus adrenaline 5 μg/ml (1:200,000 and IV saline; 4 Group CSuNeo received caudal sufentanil plus neostigmine, and IV saline; and 5 Group CSuNeoAdr received caudal sufentanil plus neostigmine plus adrenaline, and IV saline. Heart rate and mean blood pressure >15% was treated with increasing isoflurane concentration. Consumption of isoflurane, side effects, quality of sleep, time to first administration of analgesic, and number of doses of 24-h rescue analgesic were recorded. Results: Groups were demographically similar. Isoflurane consumption showed the following association: Group IVSu = Group CSuNeo = Group CSuNeoAdr Group CSuNeo = Group CSuNeoAdr (P < 0.005. Incidence of adverse effects was similar among groups. Conclusion: Caudal sufentanil alone was no better than when administered in the IV route, and would just be justified by the association of neostigmine, but not adrenaline. Neostigmine association resulted in better perioperative analgesia.

Observation of slant column NO2 using the super-zoom mode of AURA-OMI

NARCIS (Netherlands)

Valin, L.C.; Russell, A.R.; Bucsela, E.J.; Veefkind, J.P.; Cohen, R.C.

2011-01-01

We retrieve slant column NO2 from the superzoom mode of the Ozone Monitoring Instrument (OMI) to explore its utility for understanding NOx emissions and variability. Slant column NO2 is operationally retrieved from OMI (Boersma et al., 2007; Bucsela et al., 2006) with a nadir footprint of 13×24 km2,

Steady-state, elastic-plastic growth of slanted cracks in symmetrically loaded plates

DEFF Research Database (Denmark)

Nielsen, Kim Lau; Hutchinson, J. W.

2017-01-01

parameter through the plate in the plastic zone at the crack tip. The distribution of the mode I and mode III stress intensity factors along the crack front are obtained for the elastic problem. The out-of-plane bending constraint imposed on the plate significantly influences the mixed mode behavior along......Elastic and elastic-plastic results are obtained for a semi-infinite slanted through-crack propagating in a symmetrically loaded plate strip with the aim of providing theoretical background to commonly observed plate tearing behavior. Were it is not for the slant of the crack through the thickness...... of the plate, the problem would be mode I, but due to the slant the local conditions along the crack front are a combination of mode I and mode III. A three-dimensional formulation for steady-state crack propagation is employed to generate distributions of effective stress, stress triaxiality and Lode...

Eletrophysiological study of the caudal nerve on developing rats Estudo eletrofisiológico do nervo caudal em ratos em desenvolvimento

Directory of Open Access Journals (Sweden)

Juliana Netto Maia

2010-04-01

Full Text Available PURPOSE: To non-invasively study the sensory nerve conduction of the caudal nerve of normal developing rats. METHODS: Twenty normal Wistar male rats served as subjects. Caudal nerve conduction studies were performed at 60 days from birth and weekly at end of six consecutive weeks. The caudal nerve was stimulated distally and nerve potentials were recorded proximally on the animal's tail using common "alligator" clips as surface electrodes. RESULTS: The amplitude and the conduction velocity of the caudal nerve sensory action potential increased linearly from 29±6 µV to 85±13 µV and from 34±3 m/s to 44±4 m/s, respectively, between the 8th and the 15th week of life. The equations of linear regressions were as followed: Amplitude (µV = 8.1 × weeks - 34 (R² = 0.99 and NCV (m/s = 1.2 × weeks + 25 (R² = 0.86. CONCLUSIONS: It was possible to study non-invasively the sensitive conduction of the caudal nerve of normal developing rats and describe reference values. The technique and data may be used as animal model in physiological and pathological studies.OBJETIVO: Estudar de forma não invasiva a condução nervosa sensitiva do nervo caudal em ratos normais em desenvolvimento. MÉTODOS: Vinte ratos machos Wistar foram utilizados. A conducão nervosa foi realizada a partir dos 60 dias, semanal durante seis semanas consecutivas. O nervo caudal foi estimulado distalmente, os potenciais foram registrados proximalmente na cauda do animal usando garras comum do tipo "jacaré" como eletrodos de superficie. RESULTADOS: A amplitude do potencial de ação de nervo sensitivo a velocidade de condução nervosa do nervo caudal cresceu linearmente de 29 ± 6 µV para 85 ± 13 µV e de 34 ± 3 m/s para 44 ± 4 m/s, respectivamente, entre a 8º e a 15º semana da vida do animal. As equações de regressão linear foram as seguintes: Amplitude (µV = 8,1 × semanas - 34 (R² = 0,99 e velocidade de conducao nervosa (m/s = 1,2 × semanas + 25 (R² = 0

Caudal anesthesia in pediatric surgical practice.

Science.gov (United States)

Rahman, S; Siddiqui, M A; Haque, M; Majumder, S K; Ali, M S; Majid, M A; Hasan, M R

2006-07-01

Prospective study was carried out on 100 patients since May 2005 in my private practice and in the department of pediatric surgery of MMCH. Under caudal anesthesia along with or without ketaminie induction and gas inhalation all the patients underwent different surgical procedure namely anorectal surgery (eg. anoplasty, rectal polyp), urogenital surgery (Circumcision, hypospadias, meatotomy), groin surgery (hernia, hydrocele) and foot & leg surgery. Calculated dose schedule of drugs used in anesthesia and volume were maintained. Time of giving anesthesia and time of starting analgesia were recorded. Per-operative and postoperative analgesia were evaluated. Every parent was explained regarding the merit of caudal anesthesia calculated and compared with that of general anesthesia. Application of caudal anesthesia with or without ketamine & diazepam induction can be used safely and cost effectively and may be put into protocol in many of the pediatric surgical practice both in institute and also in private practice.

Opposed slant tube diabatic sorber

Science.gov (United States)

Erickson, Donald C.

2004-01-20

A sorber comprised of at least three concentric coils of tubing contained in a shell with a flow path for liquid sorbent in one direction, a flow path for heat transfer fluid which is in counter-current heat exchange relationship with sorbent flow, a sorbate vapor port in communication with at least one of sorbent inlet or exit ports, wherein each coil is coiled in opposite direction to those coils adjoining it, whereby the opposed slant tube configuration is achieved, with structure for flow modification in the core space inside the innermost coil.

Caudal epidural anesthesia during intracavitary brachytherapy for cervical cancer

International Nuclear Information System (INIS)

Isoyama-Shirakawa, Yuko; Abe, Madoka; Nakamura, Katsumasa

2015-01-01

It has been suggested that pain control during intracavitary brachytherapy for cervical cancer is insufficient in most hospitals in Japan. Our hospital began using caudal epidural anesthesia during high-dose-rate (HDR) intracavitary brachytherapy in 2011. The purpose of the present study was to retrospectively investigate the effects of caudal epidural anesthesia during HDR intracavitary brachytherapy for cervical cancer patients. Caudal epidural anesthesia for 34 cervical cancer patients was performed during HDR intracavitary brachytherapy between October 2011 and August 2013. We used the patients' self-reported Numeric Rating Scale (NRS) score at the first session of HDR intracavitary brachytherapy as a subjective evaluation of pain. We compared NRS scores of the patients with anesthesia with those of 30 patients who underwent HDR intracavitary brachytherapy without sacral epidural anesthesia at our hospital between May 2010 and August 2011. Caudal epidural anesthesia succeeded in 33 patients (97%), and the NRS score was recorded in 30 patients. The mean NRS score of the anesthesia group was 5.17 ± 2.97, significantly lower than that of the control group's 6.80 ± 2.59 (P = 0.035). The caudal epidural block resulted in no side-effects. Caudal epidural anesthesia is an effective and safe anesthesia option during HDR intracavitary brachytherapy for cervical cancer. (author)

Do Individual Differences and Aging Effects in the Estimation of Geographical Slant Reflect Cognitive or Perceptual Effects?

Directory of Open Access Journals (Sweden)

Abigail M. Dean

2016-07-01

Full Text Available Several individual differences including age have been suggested to affect the perception of slant. A cross-sectional study of outdoor hill estimation (N = 106 was analyzed using individual difference measures of age, experiential knowledge, fitness, personality traits, and sex. Of particular note, it was found that for participants who reported any experiential knowledge about slant, estimates decreased (i.e., became more accurate as conscientiousness increased, suggesting that more conscientious individuals were more deliberate about taking their experiential knowledge (rather than perception into account. Effects of fitness were limited to those without experiential knowledge, suggesting that they, too, may be cognitive rather than perceptual. The observed effects of age, which tended to produce lower, more accurate estimates of hill slant, provide more evidence that older adults do not see hills as steeper. The main effect of age was to lower slant estimates; such effects may be due to implicit experiential knowledge acquired over a lifetime. The results indicate the impact of cognitive, rather than perceptual factors on individual differences in slant estimation.

Retroflection from slanted coastlines-circumventing the "vorticity paradox"

Directory of Open Access Journals (Sweden)

V. Zharkov

2008-12-01

Full Text Available The balance of long-shore momentum flux requires that the solution of zonally retroflecting currents involve ring shedding on the western side. An important aspect of the ring dynamics is the ring intensity α (analogous to the Rossby number, which reaches its maximum value of unity when the upstream potential vorticity (PV is zero. Friction leads to a slow-down and a decrease in α. The main difficulty is that the solution of the system of equations for conservation of mass and momentum of zonal currents leads to the conclusion that the ratio (Φ of the mass flux going into the rings and the total incoming mass flux is approximately 4α/(1+2α. This yields the "vorticity paradox" – only relatively weak rings (α≤1/2 could satisfy the necessary condition Φ≤1. Physically, this means, for example, that the momentum-flux of zero PV currents upstream is so high that, no matter how many rings are produced and, no matter what size they are, they cannot compensate for it.

To avoid this paradox, we develop a nonlinear analytical model of retroflection from a slanted non-zonal coastline. We show that when the slant of coastline (γ exceeds merely 15⁰, Φ does not reach unity regardless of the value of α. Namely, the paradox disappears even for small slants. Our slowly varying nonlinear solution does not only let us circumvent the paradox. It also gives a detailed description of the rings growth rate and the mass flux going into the rings as a function of time. For example, in the case of zero PV and zero thickness of the upper layer along the coastline, the maximal values of Φ can be approximately expressed as, 1.012+0.32exp(−γ/3.41−γ/225. Interestingly, for significant slants γ≥30⁰, the rings reach a terminal size corresponding to a balance between the β-force and both the upstream and downstream momentum fluxes. This terminal size is unrelated to the ultimate

Numerical Study on the Structural Performance of Steel Beams with Slant End-plate Connections

Directory of Open Access Journals (Sweden)

Farshad Zahmatkesh

Full Text Available Abstract Thermal effects can be one of the most harmful conditions that any steel structure should expect throughout its service life. To counteract this effect, a new beam, with a capability to dissipate thermally induced axial force by slanting of end-plate connection at both ends, is proposed. The beam was examined in terms of its elastic mechanical behavior under symmetric transverse load in presence of an elevated temperature by means of direct stiffness finite element model. The performance of such connection is defined under two resisting mechanisms; by friction force dissipation between faces of slant connection and by small upward crawling on slant plane. The presented numerical method is relatively easy and useful to evaluate the behavior of the proposed beam of various dimensions at different temperatures. Its applicability is evident through satisfactory results verification with those from experimental, analytical and commercially available finite element software. Based on the good agreement between theoretical and experimental methods, a series of design curves were developed as a safe-practical range for the slant end-plate connections which are depend on the conditions of the connection.

Sindrome de regresión caudal

OpenAIRE

Maldonado, A.; Pastor, A.; Sorni, A.; Pastor Durán, Xavier; Palomeque,A.

1995-01-01

El síndrome de regresión caudal o de agenesia sacra se caracteriza por un déficit funcional de los esfínteres y de la muscultatura de los miembros inferiores. Se suele asociar con otras malformaciones, como son las esqueléticas, genitourinarias y del tracto intestinal. La diabetes mellitus materna es uno de los factores predisponentes más destacados. Aquí se presenta un caso de síndrome de regresión caudal con insufiencia renal secundaria a la uropatía malformativa asociada. Se comentan los d...

Caudal analgesia for herniotomy: Comparative evaluation of two ...

African Journals Online (AJOL)

Objective: There is currently a wide range of volume schemes for bupivacaine caudal anesthesia. This study evaluated the quality of caudal analgesia achieved with a dosing scheme of 0.75 ml/kg compared with 0.5 ml/kg of 0.25% plain bupivacaine for herniotomy. Methods: After the institutional approval, American Society ...

Parotid salivary duct stenosis following caudal maxillectomy.

Science.gov (United States)

Mestrinho, Lisa A; Faísca, Pedro B; Niza, Maria M R E

2014-01-01

Parotid salivary duct dilation was diagnosed in a 9-year-old male dog. The dog had undergone caudal maxillectomy on the ipsilateral side 2-years prior to presentation. Treatment consisted of parotid salivary duct excision and superficial parotidectomy that lead to the resolution of clinical signs. Transient facial neuropraxia was observed immediately after surgery and resolved spontaneously after 2-weeks. Parotid salivary duct dilation should be considered as a chronic postoperative complication following caudal maxillectomy.

Actuation of a robotic fish caudal fin for low reaction torque

Science.gov (United States)

Yun, Dongwon; Kim, Kyung-Soo; Kim, Soohyun; Kyung, Jinho; Lee, Sunghee

2011-07-01

In this paper, a novel caudal fin for actuating a robotic fish is presented. The proposed caudal fin waves in a vertical direction with a specific spatial shape, which is determined by a so-called shape factor. For a specific shape factor, a traveling wave with a vertical phase difference is formed on a caudal fin during fin motion. It will be shown by the analysis that the maximum reaction torque at the joint of a caudal fin varies depending on the shape factors. Compared with a conventional plate type caudal fin, the proposed fin with a shape factor of 2π can eliminate the reaction torque perfectly, while keeping the propulsion force unchanged. The benefits of the proposed fin will be demonstrated by experiments.

Experimental investigation of piercing of high-strength steels within a critical range of slant angle

Science.gov (United States)

Senn, S.; Liewald, M.

2017-09-01

Deep drawn parts often do have complex designs and, therefore, must be trimmed or punched subsequently in a second stage. Due to the complex part geometry, most punching areas do reveal critical slant angle (angle between part surface and ram movement direction) different to perpendicular direction. Piercing within a critical range of slant angle may lead to severe damage of the cutting tool. Consequently, expensive cam units are required to transform the ram moving direction in order to perform the piercing process perpendicularly to the local part surface. For modern sheet metals, however, the described critical angle of attack has not been investigated adequately until now. Therefore, cam units are used in cases in which regular piercing with high slant angle wouldn’t be possible. Purpose of this study is to investigate influencing factors and their effect on punch damage during piercing of high strength steels with slant angles. Therefore, a modular shearing tool was designed, which allows to simply switch die parts to vary cutting clearance and cutting angle. The target size of the study is to measure the lateral deviation of the punch which is monitored by an eddy current sensor. The sensor is located in the downholder and measures the lateral punch deviation in-line during manufacturing. The deviation is mainly influenced by slant angle of workpiece surface. In relation to slang angle and sheet thickness the clearance has a small influence on the measured punch deflection.

Caudal Septal Stabilization Suturing Technique to Treat Crooked Noses.

Science.gov (United States)

Baykal, Bahadir; Erdim, Ibrahim; Guvey, Ali; Oghan, Fatih; Kayhan, Fatma Tulin

2016-10-01

To rotate the nasal axis and septum to the midline using an L-strut graft and a novel caudal septal stabilization suturing technique to treat crooked noses. Thirty-six patients were included in the study. First, an L-strut graft was prepared by excising the deviated cartilage site in all patients. Second, multiple stabilization suturing, which we describe as a caudal septal stabilization suturing technique with a "fishing net"-like appearance, was applied between the anterior nasal spine and caudal septum in all patients. This new surgical technique, used to rotate the caudal septum, was applied to 22 I-type and 14 C-type crooked noses. Correction rates for the crooked noses were compared between the 2 inclination types with angular estimations. Deviation angles were measured using the AutoCAD 2012 software package and frontal (anterior) views, with the Frankfurt horizontal line parallel to the ground. Nasal axis angles showing angle improvement graded 4 categories as excellent, good, acceptable, and unsuccessful for evaluations at 6 months after surgery in the study. The success rate in the C-type nasal inclination was 86.7% (±21.9) and 88% (±16.7) in the I-type. The overall success rate of L-strut grafting and caudal septal stabilization suturing in crooked nose surgeries was 87.5% (±18.6). "Unsuccessful" results were not reported in any of the patients. L-strut grafting and caudal septal stabilization suturing techniques are efficacious in crooked noses according to objective measurement analysis results. However, a longer follow-up duration in a larger patient population is needed.

Field gradient calculation of HTS double-pancake coils considering the slanted turns and the splice

Energy Technology Data Exchange (ETDEWEB)

Baek, Geon Woo; Kim, Jin Sub; Song, Seung Hyun; Ko, Tae Kuk [Yonsei University, Seoul (Korea, Republic of); Lee, Woo Seung [JH ENGINEERING CO., LTD., Gunpo (Korea, Republic of); Lee, On You [Korea National University of Transportation, Chungju (Korea, Republic of)

2017-03-15

To obtain Nuclear Magnetic Resonance (NMR) measurement of membrane protein, an NMR magnet is required to generate high intensity, homogeneity, and stability of field. A High-Temperature Superconducting (HTS) magnet is a promising alternative to a conventional Low-Temperature Superconducting (LTS) NMR magnet for high field, current density, and stability margin. Conventionally, an HTS coil has been wound by several winding techniques such as Single-Pancake (SP), Double-Pancake (DP), and layer-wound. The DP winding technique has been frequently used for a large magnet because long HTS wire is generally difficult to manufacture, and maintenance of magnet is convenient. However, magnetic field generated by the slanted turns and the splice leads to field inhomogeneity in Diameter of Spherical Volume (DSV). The field inhomogeneity degrades performance of NMR spectrometer and thus effect of the slanted turns and the splice should be analyzed. In this paper, field gradient of HTS double-pancake coils considering the slanted turns and the splice was calculated using Biot-Savart law and numerical integration. The calculation results showed that magnetic field produced by the slanted turns and the splice caused significant inhomogeneity of field.

Sensory nerve conduction in the caudal nerves of rats with diabetes Condução nervosa sensorial no nervo caudal de ratos com diabetes experimental

OpenAIRE

Celina Cordeiro de Carvalho; Juliana Netto Maia; Otávio Gomes Lins; Sílvia Regina Arruda de Moraes

2011-01-01

PURPOSE: To investigate sensory nerve conduction of the caudal nerve in normal and diabetic rats. METHODS: Diabetes was induced in twenty 8-weeks old Wistar male rats. Twenty normal rats served as controls. Caudal nerve conduction studies were made before diabetes induction and the end of each week for six consecutive weeks. The caudal nerve was stimulated distally and nerve potentials were recorded proximally on the animal's tail using common "alligator" clips as surface electrodes. RESULTS:...

Error of the slanted edge method for measuring the modulation transfer function of imaging systems.

Science.gov (United States)

Xie, Xufen; Fan, Hongda; Wang, Hongyuan; Wang, Zebin; Zou, Nianyu

2018-03-01

The slanted edge method is a basic approach for measuring the modulation transfer function (MTF) of imaging systems; however, its measurement accuracy is limited in practice. Theoretical analysis of the slanted edge MTF measurement method performed in this paper reveals that inappropriate edge angles and random noise reduce this accuracy. The error caused by edge angles is analyzed using sampling and reconstruction theory. Furthermore, an error model combining noise and edge angles is proposed. We verify the analyses and model with respect to (i) the edge angle, (ii) a statistical analysis of the measurement error, (iii) the full width at half-maximum of a point spread function, and (iv) the error model. The experimental results verify the theoretical findings. This research can be referential for applications of the slanted edge MTF measurement method.

Prenatal diagnosis of Caudal Regression Syndrome : a case report

Directory of Open Access Journals (Sweden)

Celikaslan Nurgul

2001-12-01

Full Text Available Abstract Background Caudal regression is a rare syndrome which has a spectrum of congenital malformations ranging from simple anal atresia to absence of sacral, lumbar and possibly lower thoracic vertebrae, to the most severe form which is known as sirenomelia. Maternal diabetes, genetic predisposition and vascular hypoperfusion have been suggested as possible causative factors. Case presentation We report a case of caudal regression syndrome diagnosed in utero at 22 weeks' of gestation. Prenatal ultrasound examination revealed a sudden interruption of the spine and "frog-like" position of lower limbs. Termination of pregnancy and autopsy findings confirmed the diagnosis. Conclusion Prenatal ultrasonographic diagnosis of caudal regression syndrome is possible at 22 weeks' of gestation by ultrasound examination.

Asymmetric valley-resolved beam splitting and incident modes in slanted graphene junctions

International Nuclear Information System (INIS)

Hsieh, S. H.; Chu, C. S.

2016-01-01

Electron injection into a graphene sheet through a slanted armchair graphene nanoribbon (AGNR) is investigated. An incident mode, or subband, in the AGNR is valley-unpolarized. Our attention is on the valley-resolved nature of the injected electron beams and its connection to the incident mode. It is known for a normal injection that an incident mode will split symmetrically into two valley-resolved beams of equal intensity. We show, in contrast, that slanted injections result in asymmetric valley-resolved beam splitting. The most asymmetric beam splitting cases, when one of the valley-resolved beams has basically disappeared, are found and the condition derived. This is shown not due to trigonal warping because it holds even in the low incident energy regime, as long as collimation allows. These most asymmetric beam splitting cases occur at energies within an energy interval near and include the subband edge of an incident mode. The physical picture is best illustrated by a projection of the slanted AGNR subband states onto that of the 2D graphene sheet. It follows that the disappearing of a valley-resolved beam coincides with the situation that the group velocities of the projected states in the corresponding valley are in backward directions

Observation of slant column NO2 using the super-zoom mode of AURA-OMI

Directory of Open Access Journals (Sweden)

R. C. Cohen

2011-09-01

Full Text Available We retrieve slant column NO2 from the super-zoom mode of the Ozone Monitoring Instrument (OMI to explore its utility for understanding NOx emissions and variability. Slant column NO2 is operationally retrieved from OMI (Boersma et al., 2007; Bucsela et al., 2006 with a nadir footprint of 13 × 24 km2, the result of averaging eight detector elements on board the instrument. For 85 orbits in late 2004, OMI reported observations from individual "super-zoom" detector elements (spaced at 13 × 3 km2 at nadir. We assess the spatial response of these individual detector elements in-flight and determine an upper-bound on spatial resolution of 9 km, in good agreement with on-ground calibration (7 km FWHM. We determine the precision of the super-zoom mode to be 2.1 × 1015 molecules cm−2, approximately a factor of √8 lower than an identical retrieval at operational scale as expected if random noise dominates the uncertainty. We retrieve slant column NO2 over the Satpura power plant in India; Seoul, South Korea; Dubai, United Arab Emirates; and a set of large point sources on the Rihand Reservoir in India using differential optical absorption spectroscopy (DOAS. Over these sources, the super-zoom mode of OMI observes variation in slant column NO2 of up to 30 × the instrumental precision within one operational footprint.

Variations in the formation of the human caudal spinal cord.

Science.gov (United States)

Saraga-Babić, M; Sapunar, D; Wartiovaara, J

1995-01-01

Collection of 15 human embryos between 4-8 developmental weeks was used to histologically investigate variations in the development of the caudal part of the spinal cord and the neighboring axial organs (notochord and vertebral column). In the 4-week embryo, two types of neurulation were parallelly observed along the anteroposterior body axis: primary in the areas cranial to the neuroporus caudalis and secondary in the more caudal tail regions. In the 5-week embryos, both parts of the neural tube fused, forming only one continuous lumen in the developing spinal cord. In the three examined embryos we found anomalous pattern of spinal cord formation. Caudal parts of these spinal cords displayed division of their central canal into two or three separate lumina, each surrounded by neuroepithelial layer. In the caudal area of the spinal cord, derived by secondary neurulation, formation of separate lumina was neither connected to any anomalous notochord or vertebral column formation, nor the appearance of any major axial disturbances. We suggest that development of the caudal part of the spinal cord differs from its cranial region not only in the type of neurulation, but also in the destiny of its derivatives and possible modes of abnormality formation.

Direct Evidence for the Economy of Action: Glucose and the Perception of Geographical Slant

Science.gov (United States)

Schnall, Simone; Zadra, Jonathan R.; Proffitt, Dennis R.

2012-01-01

When locomoting in a physically challenging environment, the body draws upon available energy reserves to accommodate increased metabolic demand. Ingested glucose supplements the body’s energy resources, whereas non-caloric sweetener does not. Two experiments demonstrate that participants who had consumed a glucose-containing drink perceived a hills slant to be less steep than did participants who had consumed a drink containing non-caloric sweetener. The glucose manipulation influenced participants’ explicit awareness of hill slant but, as predicted, it did not affect a visually-guided action of orienting a tilting palmboard to be parallel to the hill. Measured individual differences in factors related to bioenergetic state such as fatigue, sleep quality, fitness, mood, and stress also affected perception such that lower energetic states were associated with steeper perceptions of hill slant. This research shows that the perception of the environment’s spatial layout is influenced by the energetic resources available for locomotion within it. Our findings are consistent with the view that spatial perceptions are influenced by bioenergetic factors. PMID:20514996

Fabrication and characterization of a slanting-type solar water ...

African Journals Online (AJOL)

The system includes four major components; a wooden basin of surface area 0.16 m2, an absorber surface, a slanting glass roof and a condensate channel. Very cheap locally available materials were used to fabricate the solar still. The solar still produced an average of 0.09 m3 of distilled water per day, and this study was ...

Sirenomelia and caudal malformations in two families.

Science.gov (United States)

Gerard, Marion; Layet, Valérie; Costa, Teresa; Roumazeilles, Yves; Chenal, Pierre; Cailliez, Daniel; Gerard, Bénédicte

2012-07-01

We report on two families with co-occurrence of sirenomelia and caudal malformations. In the first family, the mother had undergone surgery for a short form of imperforate anus. Her first pregnancy was terminated because of bilateral renal agenesis with oligohydramnios. Her second pregnancy was interrupted because of sirenomelia. The second family was referred to us because of caudal malformation in their two children. The parents' spinal radiographs were normal. The first pregnancy resulted in a girl with imperforate anus, absence of S3-S5 and coccyx, abnormal pelvic floor, and an almost bifid anteriorly located bladder. The second pregnancy resulted in a baby girl with sirenomelia. No diabetes was present during the pregnancies in either of these two families. These families confirm the hypothesis that major genes are responsible for the embryogenesis of the caudal part of the embryo, with variable expression, as has been already described in sirenomelia mouse models (CYP26A1, BMP7/tsg). Molecular studies are underway in these families and in sporadic cases in our laboratory to explore the genetic basis of sirenomelia in humans. Copyright © 2012 Wiley Periodicals, Inc.

Deferred slanted-edge analysis: a unified approach to spatial frequency response measurement on distorted images and color filter array subsets.

Science.gov (United States)

van den Bergh, F

2018-03-01

The slanted-edge method of spatial frequency response (SFR) measurement is usually applied to grayscale images under the assumption that any distortion of the expected straight edge is negligible. By decoupling the edge orientation and position estimation step from the edge spread function construction step, it is shown in this paper that the slanted-edge method can be extended to allow it to be applied to images suffering from significant geometric distortion, such as produced by equiangular fisheye lenses. This same decoupling also allows the slanted-edge method to be applied directly to Bayer-mosaicked images so that the SFR of the color filter array subsets can be measured directly without the unwanted influence of demosaicking artifacts. Numerical simulation results are presented to demonstrate the efficacy of the proposed deferred slanted-edge method in relation to existing methods.

Cranial and caudal mesenteric arteries of the paca (Cuniculus paca, L. 1766

Directory of Open Access Journals (Sweden)

Isabela Cristina de Souza Marques

2013-03-01

Full Text Available The paca (Cuniculus paca, Linnaeus, 1766 is a medium-sized rodent that occurs in Brazil; however, there is little information regarding its morphology. The goal of this study was to describe the origin and branching of the cranial and caudal mesenteric arteries of this rodent in order to contribute to comparative anatomy studies. Ten animals (males and females were used. After death, their thoracic inlet was opened between the fourth and sixth ribs to expose the thoracic aorta, which was cannulated caudally. A stained, neoprene latex solution was then injected, in order to fill the arterial system, and the preparations were fixed in a 10% aqueous formalin solution for over 72h. The fixed specimens were dissected to identify the cranial and caudal mesenteric arteries. The cranial mesenteric artery started at the abdominal aorta, caudally to the celiac artery, and originated in the following arterial branches: caudal pancreatic duodenal, pancreatic, jejunal, ileum colic and cecal. The origin of the caudal mesenteric artery occurred next to the end of abdominal aorta and this vessel issued the left colic artery and cranial rectal artery from which the sigmoid arteries initiated. It was found that there was little difference in the branching pattern of the arteries compared to other rodents and domestic mammals.

Modelling unidirectional liquid spreading on slanted microposts

DEFF Research Database (Denmark)

Cavalli, Andrea; Blow, Matthew L.; Yeomans, Julia M.

2013-01-01

A lattice Boltzmann algorithm is used to simulate the slow spreading of drops on a surface patterned with slanted micro-posts. Gibb's pinning of the interface on the sides or top of the posts leads to unidirectional spreading over a wide range of contact angles and inclination angles of the posts....... Regimes for spreading in no, one or two directions are identified, and shown to agree well with a two-dimensional theory proposed in Chu, Xiao and Wang. A more detailed numerical analysis of the contact line shapes allows us to understand deviations from the two dimensional model, and to identify...

Rock deformation equations and application to the study on slantingly installed disc cutter

Science.gov (United States)

Zhang, Zhao-Huang; Meng, Liang; Sun, Fei

2014-08-01

At present the mechanical model of the interaction between a disc cutter and rock mainly concerns indentation experiment, linear cutting experiment and tunnel boring machine (TBM) on-site data. This is not in line with the actual rock-breaking movement of the disc cutter and impedes to some extent the research on the rock-breaking mechanism, wear mechanism and design theory. Therefore, our study focuses on the interaction between the slantingly installed disc cutter and rock, developing a model in accordance with the actual rock-breaking movement. Displacement equations are established through an analysis of the velocity vector at the rock-breaking point of the disc cutter blade; the functional relationship between the displacement parameters at the rock-breaking point and its rectangular coordinates is established through an analysis of micro-displacement vectors at the rock-breaking point, thus leading to the geometric equations of rock deformation caused by the slantingly installed disc cutter. Considering the basically linear relationship between the cutting force of disc cutters and the rock deformation before and after the leap break of rock, we express the constitutive relations of rock deformation as generalized Hooke's law and analyze the effect of the slanting installation angle of disc cutters on the rock-breaking force. This will, as we hope, make groundbreaking contributions to the development of the design theory and installation practice of TBM.

DIABETES MELLITUS AND ITS ROLE IN CAUDAL REGRESSION SYNDROME

Directory of Open Access Journals (Sweden)

Sandeep

2016-03-01

Full Text Available BACKGROUND Caudal regression syndrome also called as sacral agenesis or hypoplasia of the sacrum is a congenital disorder in which there is abnormal development of the lower part of the vertebral column 1 due to which there is a plethora of abnormalities such as gross motor deficiencies and other genitor-urinary malformations which in deed depends on the extent of malformations that is seen. Caudal regression syndrome is rare, with an estimated incidence of 1:7500-100,000. The aim of the study is to find the frequency of manifestations and the manifestations itself. METHODS Fifty patients who were pregnant and were diagnosed with diabetes mellitus were identified and were referred to the Department of Medicine. RESULTS In the present study the frequency of manifestations of caudal regression syndrome is 8 in 100 diagnosed patients. CONCLUSION The malformations in the babies born to diabetic mothers are high in the population of costal Karnataka and Kerala.

Grey water treatment by the slanted soil system with unsorted soil media.

Science.gov (United States)

Ushijima, Ken; Tanaka, Erina; Suzuki, Laís Yuko; Hijikata, Nowaki; Funamizu, Naoyuki; Ito, Ryusei

2015-01-01

This study evaluated the performance of unsorted soil media in the slanted soil treatment system, in terms of removal efficiency in suspended solids (SS), chemical oxygen demand (COD), linear alkylbenzene sulphonate (LAS) and Escherichia coli, and lifetime until clogging occurs. Unsorted soil performed longer lifetime until clogging than sorted fine soil. Removal of SS, COD, and LAS also performed same or better level in unsorted soil than fine soil. As reaction coefficients of COD and LAS were described as a function of the hydraulic loading rate, we can design a slanted soil system according to the expected hydraulic loading rate and the targeted level of COD or LAS in effluent. Regarding bacteria removal, unsorted soil performed sufficient reduction of E. coli for 5 weeks; however, the removal process occurred throughout all four chambers, while that of fine soil occurred in one to two chambers.

Fourier method for modeling slanted lamellar gratings of arbitrary end-surface shapes in conical mounting.

Science.gov (United States)

Li, Lifeng

2015-10-01

An efficient modal method for numerically modeling slanted lamellar gratings of isotropic dielectric or metallic media in conical mounting is presented. No restrictions are imposed on the slant angle and the length of the lamellae. The end surface of the lamellae can be arbitrary, subject to certain restrictions. An oblique coordinate system that is adapted to the slanted lamella sidewalls allows the most efficient way of representing and manipulating the electromagnetic fields. A translational coordinate system that is based on the oblique Cartesian coordinate system adapts to the end-surface profile of the lamellae, so that the latter can be handled simply and easily. Moreover, two matrix eigenvalue problems of size 2N × 2N, one for each fundamental polarization of the electromagnetic fields in the periodic lamellar structure, where N is the matrix truncation number, are derived to replace the 4N × 4N eigenvalue problem that has been used in the literature. The core idea leading to this success is the polarization decomposition of the electromagnetic fields inside the periodic lamellar region when the fields are expressed in the oblique translational coordinate system.

Prospective Randomized Controlled Comparison of Caudal ...

African Journals Online (AJOL)

Background: Bupivacaine and ropivacaine are commonly used agents for caudal anesthesia in pediatric patients. Several studies have shown different motor and cardiovascular effects of two drugs. Aim: The primary objective of this study was to evaluate the efficacy of both drugs and secondary objective was to compare ...

Prospective Randomized Controlled Comparison of Caudal ...

African Journals Online (AJOL)

including 50 consecutive patients in the age group of 1‑10 years, who underwent urogenital surgeries ... The duration of absolute analgesia was defined as the time from caudal injection until the pain score was >2. Motor block was assessed by modified Bromage scale. .... double-blind, phase III, controlled trial comparing.

Caudal Regression Syndrome/neurogenic bladder presented as ...

African Journals Online (AJOL)

Burhan M. Edrees

Impaired development in the caudal region will affect the general health status of ... mities within the spinal cord, brain, or nervous supply. A number .... The parenchyma of left ... The findings have shown non-functioning right kidney; however,.

Groundwater flow to a horizontal or slanted well in an unconfined aquifer

Science.gov (United States)

Zhan, Hongbin; Zlotnik, Vitaly A.

2002-07-01

New semianalytical solutions for evaluation of the drawdown near horizontal and slanted wells with finite length screens in unconfined aquifers are presented. These fully three-dimensional solutions consider instantaneous drainage or delayed yield and aquifer anisotropy. As a basis, solution for the drawdown created by a point source in a uniform anisotropic unconfined aquifer is derived in Laplace domain. Using superposition, the point source solution is extended to the cases of the horizontal and slanted wells. The previous solutions for vertical wells can be described as a special case of the new solutions. Numerical Laplace inversion allows effective evaluation of the drawdown in real time. Examples illustrate the effects of well geometry and the aquifer parameters on drawdown. Results can be used to generate type curves from observations in piezometers and partially or fully penetrating observation wells. The proposed solutions and software are useful for the parameter identification, design of remediation systems, drainage, and mine dewatering.

Asymmetric liquid wetting and spreading on surfaces with slanted micro-pillar arrays

KAUST Repository

Yang, Xiaoming

2013-01-01

Uni-directional liquid spreading on asymmetric silicone-fabricated nanostructured surfaces has recently been reported. In this work, uniformly deflected polydimethylsiloxane (PDMS) micro-pillars covered with silver films were fabricated. Asymmetric liquid wetting and spreading behaviors in a preferential direction were observed on the slanted micro-pillar surfaces and a micro-scale thin liquid film advancing ahead of the bulk liquid droplet was clearly observed by high-speed video imaging. It is found that the slanted micro-pillar array is able to promote or inhibit the propagation of this thin liquid film in different directions by the asymmetric capillary force. The spreading behavior of the bulk liquid was guided and finally controlled by this micro-scale liquid film. Different spreading regimes are defined by the relationship between the liquid intrinsic contact angle and the critical angles, which were determined by the pillar height, pillar deflection angle and inter-pillar spacing. © The Royal Society of Chemistry 2013.

Note: Dynamic analysis of a robotic fish motion with a caudal fin with vertical phase differences

Science.gov (United States)

Yun, Dongwon; Kim, Kyung-Soo; Kim, Soohyun; Kyung, Jinho; Lee, Sunghwi

2013-03-01

In this paper, a robotic fish with a caudal fin with vertical phase differences is studied, especially focusing on the energy consumption. Energies for thrusting a conventional robotic fish and one with caudal fin with vertical phase differences are obtained and compared each other. It is shown that a robotic fish with a caudal fin with vertical phase differences can save more energy, which implies the efficient thrusting via a vertically waving caudal fin.

The untold story of the caudal skeleton in the electric eel (ostariophysi: gymnotiformes: electrophorus.

Directory of Open Access Journals (Sweden)

Carlos David de Santana

Full Text Available Alternative hypotheses had been advanced as to the components forming the elongate fin coursing along the ventral margin of much of the body and tail from behind the abdominal region to the posterior margin of the tail in the Electric Eel, Electrophorus electricus. Although the original species description indicated that this fin was a composite of the caudal fin plus the elongate anal fin characteristic of other genera of the Gymnotiformes, subsequent researchers proposed that the posterior region of the fin was formed by the extension of the anal fin posteriorly to the tip of the tail, thereby forming a "false caudal fin." Examination of ontogenetic series of the genus reveal that Electrophorus possesses a true caudal fin formed of a terminal centrum, hypural plate and a low number of caudal-fin rays. The confluence of the two fins is proposed as an additional autapomorphy for the genus. Under all alternative proposed hypotheses of relationships within the order Gymnotiformes, the presence of a caudal fin in Electrophorus optimized as being independent of the occurence of the morphologically equivalent structure in the Apteronotidae. Possible functional advantages to the presence of a caudal fin in the genus are discussed.

Multidetector row computed tomography and ultrasound characteristics of caudal vena cava duplication in dogs.

Science.gov (United States)

Bertolini, Giovanna; Diana, Alessia; Cipone, Mario; Drigo, Michele; Caldin, Marco

2014-01-01

Caudal vena cava duplication has been rarely reported in small animals. The purpose of this retrospective study was to describe characteristics of duplicated caudal vena cava in a large group of dogs. Computed tomography (CT) and ultrasound databases from two hospitals were searched for canine reports having the diagnosis "double caudal vena cava." One observer reviewed CT images for 71 dogs and two observers reviewed ultrasound images for 21 dogs. In all CT cases, the duplication comprised two vessels that were bilaterally symmetrical and approximately the same calibre (similar to Type I complete duplication in humans). In all ultrasound cases, the duplicated caudal vena cava appeared as a distinct vessel running on the left side of the abdominal segment of the descending aorta and extending from the left common iliac vein to the left renal vein. The prevalence of caudal vena cava duplication was 0.46% for canine ultrasound studies and 2.08% for canine CT studies performed at these hospitals. Median body weight for affected dogs was significantly lower than that of unaffected dogs (P dogs, caudal vena cava duplication should be differentiated from other vascular anomalies when planning surgeries and for avoiding misdiagnoses. © 2014 American College of Veterinary Radiology.

Rat disc torsional mechanics: effect of lumbar and caudal levels and axial compression load.

Science.gov (United States)

Espinoza Orías, Alejandro A; Malhotra, Neil R; Elliott, Dawn M

2009-03-01

Rat models with altered loading are used to study disc degeneration and mechano-transduction. Given the prominent role of mechanics in disc function and degeneration, it is critical to measure mechanical behavior to evaluate changes after model interventions. Axial compression mechanics of the rat disc are representative of the human disc when normalized by geometry, and differences between the lumbar and caudal disc have been quantified in axial compression. No study has quantified rat disc torsional mechanics. Compare the torsional mechanical behavior of rat lumbar and caudal discs, determine the contribution of combined axial load on torsional mechanics, and compare the torsional properties of rat discs to human lumbar discs. Cadaveric biomechanical study. Cyclic torsion without compressive load followed by cyclic torsion with a fixed compressive load was applied to rat lumbar and caudal disc levels. The apparent torsional modulus was higher in the lumbar region than in the caudal region: 0.081+/-0.026 (MPa/degrees, mean+/-SD) for lumbar axially loaded; 0.066+/-0.028 for caudal axially loaded; 0.091+/-0.033 for lumbar in pure torsion; and 0.056+/-0.035 for caudal in pure torsion. These values were similar to human disc properties reported in the literature ranging from 0.024 to 0.21 MPa/degrees. Use of the caudal disc as a model may be appropriate if the mechanical focus is within the linear region of the loading regime. These results provide support for use of this animal model in basic science studies with respect to torsional mechanics.

Caudal Duplication Syndrome: the Vital Role of a Multidisciplinary Approach and Staged Correction.

Science.gov (United States)

Samuk, Inbal; Levitt, Marc; Dlugy, Elena; Kravarusic, Dragan; Ben-Meir, David; Rajz, Gustavo; Konen, Osnat; Freud, Enrique

2016-12-01

Caudal duplication syndrome is a rare entity that describes the association between congenital anomalies involving caudal structures and may have a wide spectrum of clinical manifestations. A full-term male presented with combination of anomalies including anorectal malformation, duplication of the colon and lower urinary tract, split of the lower spine, and lipomyelomeningocele with tethering of the cord. We report this exceptional case of caudal duplication syndrome with special emphasis on surgical strategy and approach combining all disciplines involved. The purpose of this report is to present the pathology, assessment, and management strategy of this complex case.

Caudal Duplication Syndrome: the Vital Role of a Multidisciplinary Approach and Staged Correction

Science.gov (United States)

Samuk, Inbal; Levitt, Marc; Dlugy, Elena; Kravarusic, Dragan; Ben-Meir, David; Rajz, Gustavo; Konen, Osnat; Freud, Enrique

2015-01-01

Caudal duplication syndrome is a rare entity that describes the association between congenital anomalies involving caudal structures and may have a wide spectrum of clinical manifestations. A full-term male presented with combination of anomalies including anorectal malformation, duplication of the colon and lower urinary tract, split of the lower spine, and lipomyelomeningocele with tethering of the cord. We report this exceptional case of caudal duplication syndrome with special emphasis on surgical strategy and approach combining all disciplines involved. The purpose of this report is to present the pathology, assessment, and management strategy of this complex case. PMID:28018799

MAX-DOAS formaldehyde slant column measurements during CINDI: intercomparison and analysis improvement

Directory of Open Access Journals (Sweden)

G. Pinardi

2013-01-01

Full Text Available We present intercomparison results for formaldehyde (HCHO slant column measurements performed during the Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments (CINDI that took place in Cabauw, the Netherlands, in summer 2009. During two months, nine atmospheric research groups simultaneously operated MAX-DOAS (MultiAXis Differential Optical Absorption Spectroscopy instruments of various designs to record UV-visible spectra of scattered sunlight at different elevation angles that were analysed using common retrieval settings. The resulting HCHO data set was found to be highly consistent, the mean difference between instruments generally not exceeding 15% or 7.5 × 10¹⁵ molec cm⁻², for all viewing elevation angles. Furthermore, a sensitivity analysis was performed to investigate the uncertainties in the HCHO slant column retrieval when varying key input parameters such as the molecular absorption cross sections, correction terms for the Ring effect or the width and position of the fitting interval. This study led to the identification of potentially important sources of errors associated with cross-correlation effects involving the Ring effect, O₄, HCHO and BrO cross sections and the DOAS closure polynomial. As a result, a set of updated recommendations was formulated for HCHO slant column retrieval in the 336.5–359 nm wavelength range. To conclude, an error budget is proposed which distinguishes between systematic and random uncertainties. The total systematic error is estimated to be of the order of 20% and is dominated by uncertainties in absorption cross sections and related spectral cross-correlation effects. For a typical integration time of one minute, random uncertainties range between 5 and 30%, depending on the noise level of individual instruments.

The burden of secrecy? No effect on hill slant estimation and beanbag throwing.

Science.gov (United States)

Pecher, Diane; van Mierlo, Heleen; Cañal-Bruland, Rouwen; Zeelenberg, René

2015-08-01

Slepian, Masicampo, Toosi, and Ambady (2012, Experiment 1) reported that participants who recalled a big secret estimated a hill as steeper than participants who recalled a small secret. This finding was interpreted as evidence that secrets are experienced as physical burdens. In 2 experiments, we tried to replicate this finding, but, despite larger power, did not find a difference in slant estimates between participants who recalled a big secret and those who recalled a small secret. This finding was further corroborated by a meta-analysis that included 8 published data sets of exact replications, which indicates that thinking of a big secret does not affect hill slant estimation. In a third experiment, we also failed to replicate the effect of recalling a secret on throwing a beanbag at a target (Slepian et al., 2012, Experiment 2). Together, our findings question the robustness of the original empirical findings. (c) 2015 APA, all rights reserved).

The comparative analysis of rocks' resistance to forward-slanting disc cutters and traditionally installed disc cutters

Science.gov (United States)

Zhang, Zhao-Huang; Fei, Sun; Liang, Meng

2016-08-01

At present, disc cutters of a full face rock tunnel boring machine are mostly mounted in the traditional way. Practical use in engineering projects reveals that this installation method not only heavily affects the operation life of disc cutters, but also increases the energy consumption of a full face rock tunnel boring machine. To straighten out this issue, therefore, a rock-breaking model is developed for disc cutters' movement after the research on the rock breaking of forward-slanting disc cutters. Equations of its displacement are established based on the analysis of velocity vector of a disc cutter's rock-breaking point. The functional relations then are brought forward between the displacement parameters of a rock-breaking point and its coordinate through the analysis of micro displacement of a rock-breaking point. Thus, the geometric equations of rock deformation are derived for the forward-slanting installation of disc cutters. With a linear relationship remaining between the acting force and its deformation either before or after the leap breaking, the constitutive relation of rock deformation can be expressed in the form of generalized Hooke law, hence the comparative analysis of the variation in the resistance of rock to the disc cutters mounted in the forward-slanting way with that in the traditional way. It is discovered that with the same penetration, strain of the rock in contact with forward-slanting disc cutters is apparently on the decline, in other words, the resistance of rock to disc cutters is reduced. Thus wear of disc cutters resulted from friction is lowered and energy consumption is correspondingly decreased. It will be useful for the development of installation and design theory of disc cutters, and significant for the breakthrough in the design of full face rock tunnel boring machine.

Redacción de la Constitución en clave no masculina // Wording of the Constitution in a non masculine slant

Directory of Open Access Journals (Sweden)

Antonio Torres del Moral

2017-12-01

Language is an essential component of the law. The law and the justice are expressed with words. The juridic languages have historically been expresed from the male slant. This is a trial of new wording of certain passages of the Spanish Constitution (the preamble and the articles 1 to 29 trying to overcome their male slant without changing the juridic substance.

Accessory caudal axial and pelvic ribs

International Nuclear Information System (INIS)

Bohutova, J.; Kolar, J.; Vitovec, J.; Vyhnanek, L.

1980-01-01

Accessory caudal ribs are reported as an extremely curious anomaly in five patients. Once the fracture of this rib was a source of pains after injury. The different shapes of the ribs are documented in this clinical survey which is the most extensive in the present literature. Anomalous ribs arise due to inappropriate segmentation during the embryonal development of the axial skeleton. (orig.) [de

Caudal regulates the spatiotemporal dynamics of pair-rule waves in Tribolium.

Directory of Open Access Journals (Sweden)

Ezzat El-Sherif

2014-10-01

Full Text Available In the short-germ beetle Tribolium castaneum, waves of pair-rule gene expression propagate from the posterior end of the embryo towards the anterior and eventually freeze into stable stripes, partitioning the anterior-posterior axis into segments. Similar waves in vertebrates are assumed to arise due to the modulation of a molecular clock by a posterior-to-anterior frequency gradient. However, neither a molecular candidate nor a functional role has been identified to date for such a frequency gradient, either in vertebrates or elsewhere. Here we provide evidence that the posterior gradient of Tc-caudal expression regulates the oscillation frequency of pair-rule gene expression in Tribolium. We show this by analyzing the spatiotemporal dynamics of Tc-even-skipped expression in strong and mild knockdown of Tc-caudal, and by correlating the extension, level and slope of the Tc-caudal expression gradient to the spatiotemporal dynamics of Tc-even-skipped expression in wild type as well as in different RNAi knockdowns of Tc-caudal regulators. Further, we show that besides its absolute importance for stripe generation in the static phase of the Tribolium blastoderm, a frequency gradient might serve as a buffer against noise during axis elongation phase in Tribolium as well as vertebrates. Our results highlight the role of frequency gradients in pattern formation.

Computed tomographic characteristics of collateral venous pathways in dogs with caudal vena cava obstruction.

Science.gov (United States)

Specchi, Swan; d'Anjou, Marc-André; Carmel, Eric Norman; Bertolini, Giovanna

2014-01-01

Collateral venous pathways develop in dogs with obstruction or increased blood flow resistance at any level of the caudal vena cava in order to maintain venous drainage to the right atrium. The purpose of this retrospective study was to describe the sites, causes of obstruction, and configurations of venous collateral pathways for a group of dogs with caudal vena cava obstruction. Computed tomography databases from two veterinary hospitals were searched for dogs with a diagnosis of caudal vena cava obstruction and multidetector row computed tomographic angiographic (CTA) scans that included the entire caudal vena cava. Images for each included dog were retrieved and collateral venous pathways were characterized using image postprocessing and a classification system previously reported for humans. A total of nine dogs met inclusion criteria and four major collateral venous pathways were identified: deep (n = 2), portal (n = 2), intermediate (n = 7), and superficial (n = 5). More than one collateral venous pathway was present in 5 dogs. An alternative pathway consisting of renal subcapsular collateral veins, arising mainly from the caudal pole of both kidneys, was found in three dogs. In conclusion, findings indicated that collateral venous pathway patterns similar to those described in humans are also present in dogs with caudal vena cava obstruction. These collateral pathways need to be distinguished from other vascular anomalies in dogs. Postprocessing of multidetector-row CTA images allowed delineation of the course of these complicated venous pathways and may be a helpful adjunct for treatment planning in future cases. © 2014 American College of Veterinary Radiology.

Rostro-Caudal Organization of Connectivity between Cingulate Motor Areas and Lateral Frontal Regions

Directory of Open Access Journals (Sweden)

Kep Kee Loh

2018-01-01

Full Text Available According to contemporary views, the lateral frontal cortex is organized along a rostro-caudal functional axis with increasingly complex cognitive/behavioral control implemented rostrally, and increasingly detailed motor control implemented caudally. Whether the medial frontal cortex follows the same organization remains to be elucidated. To address this issue, the functional connectivity of the 3 cingulate motor areas (CMAs in the human brain with the lateral frontal cortex was investigated. First, the CMAs and their representations of hand, tongue, and eye movements were mapped via task-related functional magnetic resonance imaging (fMRI. Second, using resting-state fMRI, their functional connectivity with lateral prefrontal and lateral motor cortical regions of interest (ROIs were examined. Importantly, the above analyses were conducted at the single-subject level to account for variability in individual cingulate morphology. The results demonstrated a rostro-caudal functional organization of the CMAs in the human brain that parallels that in the lateral frontal cortex: the rostral CMA has stronger functional connectivity with prefrontal regions and weaker connectivity with motor regions; conversely, the more caudal CMAs have weaker prefrontal and stronger motor connectivity. Connectivity patterns of the hand, tongue and eye representations within the CMAs are consistent with that of their parent CMAs. The parallel rostral-to-caudal functional organization observed in the medial and lateral frontal cortex could likely contribute to different hierarchies of cognitive-motor control.

All-solid-state thin film battery based on well-aligned slanted LiCoO{sub 2} nanowires fabricated by glancing angle deposition

Energy Technology Data Exchange (ETDEWEB)

Yoon, Miyoung [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, Seunghwan [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Daehee [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Joosun, E-mail: joosun@kist.re.kr [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Moon, Jooho, E-mail: jmoon@yonsei.ac.kr [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

2017-08-01

Graphical abstract: We successfully fabricated well-aligned slanted LiCoO{sub 2} nanowires as a one-dimensional nanostructured cathode by glancing angle deposition to enhance the electrochemical performance of all-solid-state thin film batteries. - Highlights: • Well-aligned slanted LiCoO{sub 2} nanowires are fabricated by glancing angle deposition. • One-dimensional nanostructured LiCoO{sub 2} cathode enlarges the contact area. • All-solid-state thin film battery exhibits enhances rate capability and cycling stability. - Abstract: We fabricated all-solid-state thin film batteries based on well-aligned slanted LiCoO{sub 2} nanowires by glancing angle deposition, as a facile template-free method in order to increase the electrochemically active site, i.e., the contact area between the solid electrolyte and the electrode. A highly porous thin film composed of well-separated slanted LiCoO{sub 2} nanowires not only facilitates the penetration of solid electrolyte phase into the cathode, but also alleviates the thermally and mechanically induced stresses during post-annealing and electrochemical cycling. The all-solid-state thin film battery based on the well-aligned slanted LiCoO{sub 2} nanowires, whose contact area between electrolyte and electrode was three times as high as that of a dense thin film, could provide additional migration pathways for lithium ion diffusion due to the enlarged reaction sites. This resulted in enhanced electrochemical kinetics, thereby leading to better rate capability and long-term cyclic stability as compared to the dense LiCoO{sub 2} thin film.

Caudal articular process dysplasia of thoracic vertebrae in neurologically normal French bulldogs, English bulldogs, and Pugs: Prevalence and characteristics.

Science.gov (United States)

Bertram, Simon; Ter Haar, Gert; De Decker, Steven

2018-02-20

The aims of this study were to evaluate the prevalence and anatomical characteristics of thoracic caudal articular process dysplasia in French bulldogs, English bulldogs and Pugs presenting for problems unrelated to spinal disease. In this retrospective cross-sectional study, computed tomography scans of the thoracic vertebral column of these three breeds were reviewed for the presence and location of caudal articular process hypoplasia and aplasia, and compared between breeds. A total of 271 dogs met the inclusion criteria: 108 French bulldogs, 63 English bulldogs, and 100 Pugs. A total of 70.4% of French bulldogs, 84.1% of English bulldogs, and 97.0% of Pugs showed evidence of caudal articular process dysplasia. Compared to French and English bulldogs, Pugs showed a significantly higher prevalence of caudal articular process aplasia, but also a lower prevalence of caudal articular process hypoplasia, a higher number of affected vertebrae per dog and demonstrated a generalized and bilateral spatial pattern more frequently. Furthermore, Pugs showed a significantly different anatomical distribution of caudal articular process dysplasia along the vertebral column, with a high prevalence of caudal articular process aplasia between T10 and T13. This area was almost completely spared in French and English bulldogs. As previously suggested, caudal articular process dysplasia is a common finding in neurologically normal Pugs but this also seems to apply to French and English bulldogs. The predisposition of clinically relevant caudal articular process dysplasia in Pugs is possibly not only caused by the higher prevalence of caudal articular process dysplasia, but also by breed specific anatomical characteristics. © 2018 American College of Veterinary Radiology.

Applications of slant collimators to cardiovascular nuclear medicine

International Nuclear Information System (INIS)

Nishimura, Tsunehiko; Uehara, Toshio; Hayashi, Makoto; Kagawa, Masaaki; Kozuka, Takahiro

1980-01-01

The RI examination of hearts is attracting increasingly interest as cardiovascular nuclear medicine in recent years. As for the background, there are the development of such radioactive agents with high heart-muscle specificity as 201 TICI and the minicomputer capability of measuring rapid contraction and expansion of hearts. Under the situation, the variety of contrivance in collimators is attempted for higher accuracy in grasping the form and function of hearts. With a 30 deg inclination slant type collimator (made by EDC firm) which became available, its applications as cardiovascular nuclear medicine have been examined in heart-muscle scintigraphy and heart RI angiography. These results are described. In the above connection, a bifocal collimator and a seven pinhole collimator are also explained briefly. (J.P.N.)

Comparison of Caudal Analgesia and Intravenous Diclofenac for ...

African Journals Online (AJOL)

Background: Effective postoperative pain management is a vital determinant to when a child can be safely discharged from the hospital after day case surgery. This study compared the effect of caudal bupivacaine block with intravenous diclofenac for postoperative pain relief in children aged 1-7years undergoing ...

Construction of cable-stayed prestressed concrete bridge, having Japan`s first independent single slanted tower; Nippon hatsu no keisha shuto wo motsu PC shachokyo no seko

Energy Technology Data Exchange (ETDEWEB)

Sanada, Y.; Naito, H. [Penta-Ocean Construction Co. Ltd., Tokyo (Japan); Takeuchi, H.; Mikami, T.

1994-08-01

In the Hachinoe Harbor, Aomori prefecture, a man-made island (Hachinoe Port Island) is being constructed by reclamation. When proceeding this undertaking plan, a construction of the Hachinoe Harbor Port Island connection bridge, which connects the man-made island with the existing harbor district, was made an urgent necessity. This connecting bridge is a bridge with a total length of 256.56m, and is constituted of two span continuous PC slanted bridge and three span continuous PC box girder bridge. This slanted bridge has become an asymmetrical structure due to several conditions coming from a plan, and moreover it has the first structural shape as a road bridge in Japan, of which main tower is 15{degree} slanted independent single tower type, there are more problems for the work execution compared with other normal slanted bridges. In addition, because it is situated in an extremely cruel environment like in the cold region and in the marine environment, a sufficient consideration is required for its design and work execution in order to insure a durability. In this report, an outline of work execution content about PC slanted bridge part currently under a construction zealously aiming at a completion in the end of the fiscal year 1994 is introduced. 2 refs., 14 figs., 4 tabs.

Caudal dysgenesis, sirenomelia, and situs inversus totalis: a primitive defect in blastogenesis.

Science.gov (United States)

Rougemont, Anne-Laure; Bouron-Dal Soglio, Dorothée; Désilets, Valérie; Jovanovic, Mubina; Perreault, Gilles; Laurier Oligny, Luc; Fournet, Jean-Christophe

2008-06-01

Caudal dysgenesis (CD) constitutes a heterogeneous spectrum of congenital caudal anomalies, including varying degrees of agenesis of the vertebral column, as well as anorectal and genitourinary anomalies. Sirenomelia, characterized by a fusion of the lower limbs, could represent the most severe end of this spectrum. The two main debated pathogenic hypotheses are an aberrant vascular supply versus a primary axial mesoderm defect. We present the autopsy findings of two fetuses of non-diabetic mothers, with normal karyotype. Both fetuses presented situs inversus associated with a CD, in one case consisting of sirenomelia, establishing a very rare association profile that might be random. This association also suggests the occurrence of a common pathogenic mechanism, in accordance to recent genetic data, such as displayed in the Kif3A murine mutation phenotype. Some cases of sirenomelia and CD could represent developmental field defects of blastogenesis involving the caudal mesoderm, rather than being related to vascular insufficiency.

Flow-structure Interaction Modeling of a Fish Caudal Fin during Steady Swimming

Science.gov (United States)

Liu, Geng; Geng, Biao; Zheng, Xudong; Xue, Qian; Dong, Haibo

2017-11-01

It's widely thought that the flexibilities of fish fins play critical roles in propulsive performance enhancement (such as thrust augment and efficiency improvement) in nature. In order to explore the formation mechanisms of the fish fin's flexible morphing and its hydrodynamic benefits as well, a high-fidelity flow-structure/membrane interaction modeling of the fish caudal fin is conducted in this work. Following the realistic configuration of the fish caudal fin, a thin membrane supported by a series of beams is constructed. The material properties of the membrane and the beams are reversely determined by the realistic fin morphing obtained from the high-speed videos and the high fidelity flow-structure interaction simulations. With the accurate material property, we investigate the interplay between structure, kinematics and fluid flow in caudal fin propulsion. Detailed analyses on the relationship between the flexural stiffness, fin morphing patterns, hydrodynamic forces and vortex dynamics are then conducted.

Identifying Partisan Slant in News Articles and Twitter during Political Crises

OpenAIRE

Karamshuk, Dmytro; Lokot, Tetyana; Pryymak, Oleksandr; Sastry, Nishanth

2017-01-01

In this paper, we are interested in understanding the interrelationships between mainstream and social media in forming public opinion during mass crises, specifically in regards to how events are framed in the mainstream news and on social networks and to how the language used in those frames may allow to infer political slant and partisanship. We study the lingual choices for political agenda setting in mainstream and social media by analyzing a dataset of more than 40M tweets and more than...

Conjoined twin piglets with duplicated cranial and caudal axes.

Science.gov (United States)

McManus, C A; Partlow, G D; Fisher, K R

1994-06-01

Twins with doubling of the cranial and caudal poles, yet having a single thorax, are rare. One set of diprosopus, dipygus porcine conjoined twins was studied. In addition to the conjoining anomaly, these twins also exhibited ambiguous internal reproductive features. The twins had two snouts, three eyes, a single thorax, and were duplicated from the umbilicus caudally. Radiography indicated a single vertebral column in the cervical region. The vertebral columns were separate caudally from this point. There was a total of six limbs--one pair of forelimbs and two pairs of hindlimbs. Many medial structures failed to develop in these twins. Medial cranial nerves V-XII were absent or displaced although apparently normal laterally. The medial palates were present but shortened, whereas the medial mandibular rami had folded back on themselves rostrally to form a midline mass between the two chins. Each twin had only one lateral kidney and one lateral testis. Medial scrotal sacs were present but devoid of a testis. There was a midline, "uterine"-like structure which crossed between the twins. However, histological analysis of this structure revealed it to be dysplastic testicular tissue. The relationship between the abnormal reproductive features in these twins and the conjoining is unclear. The anatomy of these twins, in addition to the literature reviewed, illustrates the internal anatomical heterogeneity of grossly similar conjoined twins. A review of the literature also suggests that conjoined twinning may be more common in swine than was previously suspected.

Two memories for geographical slant: separation and interdependence of action and awareness

Science.gov (United States)

Creem, S. H.; Proffitt, D. R.; Kaiser, M. K. (Principal Investigator)

1998-01-01

The present study extended previous findings of geographical slant perception, in which verbal judgments of the incline of hills were greatly overestimated but motoric (haptic) adjustments were much more accurate. In judging slant from memory following a brief or extended time delay, subjects' verbal judgments were greater than those given when viewing hills. Motoric estimates differed depending on the length of the delay and place of response. With a short delay, motoric adjustments made in the proximity of the hill did not differ from those evoked during perception. When given a longer delay or when taken away from the hill, subjects' motoric responses increased along with the increase in verbal reports. These results suggest two different memorial influences on action. With a short delay at the hill, memory for visual guidance is separate from the explicit memory informing the conscious response. With short or long delays away from the hill, short-term visual guidance memory no longer persists, and both motor and verbal responses are driven by an explicit representation. These results support recent research involving visual guidance from memory, where actions become influenced by conscious awareness, and provide evidence for communication between the "what" and "how" visual processing systems.

Evaluation of Anesthesia Profile in Pediatric Patients after Inguinal Hernia Repair with Caudal Block or Local Wound Infiltration.

Science.gov (United States)

Gavrilovska-Brzanov, Aleksandra; Kuzmanovska, Biljana; Kartalov, Andrijan; Donev, Ljupco; Lleshi, Albert; Jovanovski-Srceva, Marija; Spirovska, Tatjana; Brzanov, Nikola; Simeonov, Risto

2016-03-15

The aim of this study is to evaluate anesthesia and recovery profile in pediatric patients after inguinal hernia repair with caudal block or local wound infiltration. In this prospective interventional clinical study, the anesthesia and recovery profile was assessed in sixty pediatric patients undergoing inguinal hernia repair. Enrolled children were randomly assigned to either Group Caudal or Group Local infiltration. For caudal blocks, Caudal Group received 1 ml/kg of 0.25% bupivacaine; Local Infiltration Group received 0.2 ml/kg 0.25% bupivacaine. Investigator who was blinded to group allocation provided postoperative care and assessments. Postoperative pain was assessed. Motor functions and sedation were assessed as well. The two groups did not differ in terms of patient characteristic data and surgical profiles and there weren't any hemodynamic changes between groups. Regarding the difference between groups for analgesic requirement there were two major points - on one hand it was statistically significant p < 0.05 whereas on the other hand time to first analgesic administration was not statistically significant p = 0.40. There were significant differences in the incidence of adverse effects in caudal and local group including: vomiting, delirium and urinary retention. Between children undergoing inguinal hernia repair, local wound infiltration insures safety and satisfactory analgesia for surgery. Compared to caudal block it is not overwhelming. Caudal block provides longer analgesia, however complications are rather common.

Cardiocirculatory intraoperative assessment during single-shot caudal anaesthesia in children: comparison between levobupivacaine and ropivacaine

Directory of Open Access Journals (Sweden)

A. Gentili

2012-06-01

Full Text Available Background: Caudal block with levobupivacaine or ropivacaine is the most commonly used regional anaesthesia in children. Methods: The aim of study was to compare the cardiocirculatory profile induced in two matched groups of young patients, submitted to caudal anaesthesia with levobupivacaine or ropivacaine for an elective subumbilical surgery. Sixty children were enrolled: thirty received levopubivacaine 0.25% and thirty ropivacaine 0.2%. Intraoperative heart rate (HR, systolic blood pressure (SBP, diastolic blood pressure (DBP were monitored at following times: Ta0 (after anaesthesia induction, Ta1 (after caudal anaesthesia, Ta2 (five minutes later, Ta3 (ten minutes later, Ts1 (at surgical incision, Ts2, Ts3, Ts4, Ts5 (every 10 minutes during surgery, Taw (at the awakening. Results: In both groups the cardiocirculatory trend remained within normal ranges at all times considered, demonstrating the safety of the method with both drugs. Both groups showed a similar trend at the different monitoring times: low decrease in HR, SBP and DBP after caudal block, slight increase in parameters after skin incision, slight decrease during surgery, increase at awakening. Regarding SBP and DBP, the levobupivacaine group children generally showed higher levels compared to the ropivacaine group, especially for DBP. Conclusions: Paediatric caudal anaesthesia is an effective method with an very infrequent complication rate. Possible hypotheses for differing haemodynamic behaviour could include a stronger vasoconstriction reflex of innervated areas during caudal anaesthesia with levobupivacaine and a lower levobupivacaine induced block of the sympathetic fibers, related to different pharmacokinetic profile of low concentrations of the local anaesthetics used in paediatric epidural space.

Comparison of dysphagia outcomes between rostral and caudal lateral medullary infarct patients.

Science.gov (United States)

Chun, Min Ho; Kim, Daeha; Chang, Min Cheol

2017-11-01

A detailed knowledge of dysphagia outcomes in lateral medullary infarct (LMI) patients would enable proper establishment of swallowing therapy goals and strategies. However, little is known about the impact of infarct location on dysphagia outcomes in patients with LMI. Twenty patients with rostral LMI (rostral group) and 20 patients with caudal LMI (caudal group) participated in the study. All patients underwent swallowing therapy, which included compensatory treatments and strengthening exercises, for >3 months. Dysphagia evaluation was performed twice (during the subacute stage and six months after stroke onset) using videofluoroscopic swallowing studies. Dysphagia degree was assessed using the functional dysphagia scale (FDS), the penetration-aspiration scale (PAS) and the American Speech-Language-Hearing Association (ASHA) National Outcome Measurement System (NOMS) swallowing scale. In the subacute stage, the rostral group had significantly higher FDS and PAS scores and a significantly lower ASHA NOMS score than the caudal group. Patients from both groups showed significant improvement from the initial evaluation to the six-month evaluation. There were no significant differences in these scale scores between the two groups at the six-month evaluation. In the subacute stage, patients in the rostral group had more severe dysphagia than those in the caudal group. Dysphagia improved in both groups after 3-6 months of swallowing therapy. At six months after onset, there were no significant differences in dysphagia severity between the two groups. Recovery from dysphagia after LMI was observed regardless of the infarct location.

Caudal regression with sirenomelia and dysplasia renofacialis (Potter's syndrome)

International Nuclear Information System (INIS)

Noeldge, G.; Billmann, P.; Boehm, N.; Freiburg Univ.

1982-01-01

A case of caudal regression in combination with sirenomelia and dysplasia renofacialis (Potter's syndrome) is reported. The formal pathogenesis of these malformations and clinical facts are shown and discussed. Findings of plain films, postmortal angiography and pathologic-anatomical changes are demonstrated. (orig.) [de

Alteration of Na-K pump activity in supersensitive rat caudal artery following 6-hydroxydopamine (6-OHDA) treatment

International Nuclear Information System (INIS)

Wong, S.K.; Foley, D.H.

1986-01-01

Contractile response and the Na-K pump activity, measured as ouabain-sensitive 86 Rb-uptake, were determined in caudal artery strips of rats pretreated with 6-OHDA. At 6-7 days after 6-OHDA treatment, the potencies of norepinephrine and serotonin in causing contraction of rat caudal artery were significantly increased by 2.3 - and 1.7 - fold respectively. There was, however, no change in maximum contractile response to either agent. Treatment with 6-OHDA also reduced endogenous catecholamine content of the caudal artery to 7% of the control. Analysis of ouabain-inhibitable 86 Rb-uptake of rat caudal artery by the double-reciprocal plots showed that both the rate of 86 Rb-uptake and the affinity for rubidium were depressed after 6-OHDA treatment. The results indicate that 6-OHDA induced supersensitivity in the rat caudal artery is associated with a decrease in the Na-K pump activity. These data provide additional support to the concept that inhibition of the Na-K pump may result in partial depolarization of the cell membrane which leads to supersensitivity of smooth muscle to excitatory drugs

Aguas de un mismo caudal

Directory of Open Access Journals (Sweden)

Carlos Morales

2015-01-01

Full Text Available Borges, creía que “el periodismo distorsiona la mentalidad del escritor”, el autor de este artículo, plantea en cambio que son “aguas de un mismo caudal, que muy a menudo viajan juntas”, varias han sido, y son, las concepciones que han expuesto célebres protagonistas de estos dos hechos escriturales a favor y en contra del ejercicio del periodismo para mejorar o perjudicar al escritor. El aparente divorcio entre literatura y periodismo radica cabalmente en el intento equivocado de separarlos. En verdad son lo mismo y bien podríamos clasificar al periodismo como un género dentro de la literatura.

The association between caudal anesthesia and increased risk of postoperative surgical complications in boys undergoing hypospadias repair.

Science.gov (United States)

Taicher, Brad M; Routh, Jonathan C; Eck, John B; Ross, Sherry S; Wiener, John S; Ross, Allison K

2017-07-01

Recent reports have suggested that caudal anesthesia may be associated with an increased risk of postoperative surgical complications. We examined our experience with caudal anesthesia in hypospadias repair to evaluate for increased risk of urethrocutaneous fistula or glanular dehiscence. All hypospadias repairs performed by a single surgeon in 2001-2014 were reviewed. Staged or revision surgeries were excluded. Patient age, weight, hypospadias severity, surgery duration, month and year of surgery, caudal anesthesia use, and postoperative complications were recorded. Bivariate and multivariate statistical analyses were performed. We identified 395 single-stage primary hypospadias repairs. Mean age was 15.6 months; 326 patients had distal (83%) and 69 had proximal (17%) hypospadias. Caudal anesthetics were used in 230 (58%) cases; 165 patients (42%) underwent local penile block at the discretion of the surgeon and/or anesthesiologist. Complications of urethrocutaneous fistula or glanular deshiscence occurred in 22 patients (5.6%) and were associated with caudal anesthetic use (OR 16.5, 95% CI 2.2-123.8, P = 0.007), proximal hypospadias (OR 8.2, 95% CI 3.3-20.0, P anesthesia was associated with an over 13-fold increase in the odds of developing postoperative surgical complications in boys undergoing hypospadias repair even after adjusting for urethral meatus location. Until further investigation occurs, clinicians should carefully consider the use of caudal anesthesia for children undergoing hypospadias repair. © 2017 John Wiley & Sons Ltd.

Measurement of the modulation transfer function of a charge-coupled device array by the combination of the self-imaging effect and slanted edge method.

Science.gov (United States)

Najafi, Sedigheh; Madanipour, Khosro

2013-07-01

In this paper, by a combination of the self-imaging effect for Ronchi gratings and the standard slanted edge modulation transfer function (MTF) measurement method for CCD cameras, the MTF of the CCD array without optics is measured. For this purpose, a Ronchi-type grating is illuminated by an expanded He-Ne laser. A self-image of the grating appears without optics on the CCD array that is located on the Talbot distance. The lines of the self-image of the grating are used as a slanted edge array. This method has all the advantages of the slanted edge method, and also since the array of the edge is ready, the total area of the CCD can be tested. The measured MTF is related to the CCD array without optics.

Ultrasound as a Screening Tool for Performing Caudal Epidural Injections

International Nuclear Information System (INIS)

Nikooseresht, Mahshid; Hashemi, Masoud; Mohajerani, Seyed Amir; Shahandeh, Farideh; Agah, Mahvash

2014-01-01

The caudal approach to the epidural space has been used for decades to treat low back pain caused by lumbosacral root compression. The use of fluoroscopy during epidural steroid injection is the preferred method for placing the needle more accurately in the sacral hiatus, but it carries the risk of radiation hazard. The aim of the study was to assess the anatomical structure of the sacral hiatus and the feasibility of caudal epidural injections under ultrasound guidance. Two hundred and forty patients (male = 100, female = 140) with low back pain and sciatica who were candidates for caudal epidural injection were enrolled into this study. Ultrasound images of the sacral hiatus and bilateral cornua were obtained by a real-time linear array ultrasound transducer. The distance between bilateral cornua and the anterior and posterior wall of the sacrum were measured at the base (sacral hiatus). Under the guide of ultrasonography, we defined the injection successful if turbulence of medication fluid was observed in the sacral canal, but correct placement of the needle and injectant was confirmed on fluoroscopic view as the gold standard technique. The epidurogram showed that the injection was successful in 230 of the 240 patients (95.8%). In eight patients, the injection was not in the correct place in the sacral canal. The sacral hiatus could not be identified by ultrasound images in only two patients who had a closed sacral hiatus identified by fluoroscopy. The mean distance of the sacral hiatus was 4.7 ± 1.7 mm and the mean distance between bilateral cornua was 18.0 ± 2.8 mm. The mean duration of the procedure was 10.8 ± 6.8 minutes. No major complication was observed in the next month. In conclusion, ultrasound could be used as a safe, fast and reliable modality to observe the anatomic variation of the sacral hiatus and to perform caudal epidural injections

Caudal pneumaticity and pneumatic hiatuses in the sauropod dinosaurs Giraffatitan and Apatosaurus.

Directory of Open Access Journals (Sweden)

Mathew J Wedel

Full Text Available Skeletal pneumaticity is found in the presacral vertebrae of most sauropod dinosaurs, but pneumaticity is much less common in the vertebrae of the tail. We describe previously unrecognized pneumatic fossae in the mid-caudal vertebrae of specimens of Giraffatitan and Apatosaurus. In both taxa, the most distal pneumatic vertebrae are separated from other pneumatic vertebrae by sequences of three to seven apneumatic vertebrae. Caudal pneumaticity is not prominent in most individuals of either of these taxa, and its unpredictable development means that it may be more widespread than previously recognised within Sauropoda and elsewhere in Saurischia. The erratic patterns of caudal pneumatization in Giraffatitan and Apatosaurus, including the pneumatic hiatuses, show that pneumatic diverticula were more broadly distributed in the bodies of the living animals than are their traces in the skeleton. Together with recently published evidence of cryptic diverticula--those that leave few or no skeletal traces--in basal sauropodomorphs and in pterosaurs, this is further evidence that pneumatic diverticula were widespread in ornithodirans, both across phylogeny and throughout anatomy.

Design, data, and theory regarding a digital hand inclinometer: a portable device for studying slant perception.

Science.gov (United States)

Li, Zhi; Durgin, Frank H

2011-06-01

Palm boards are often used as a nonverbal measure in human slant perception studies. It was recently found that palm boards are biased and relatively insensitive measures, and that an unrestricted hand gesture provides a more sensitive response (Durgin, Hajnal, Li, Tonge, & Stigliani, Acta Psychologica, 134, 182-197, 2010a). In this article, we describe an original design for a portable lightweight digital device for measuring hand orientation. This device is microcontroller-based and uses a micro inclinometer chip as its inclination sensor. The parts are fairly inexpensive. This device, used to measure hand orientation, provides a sensitive nonverbal method for studying slant perception, which can be used in both indoor and outdoor environments. We present data comparing the use of a free hand to palm-board and verbal measures for surfaces within reach and explain how to interpret free-hand measures for outdoor hills.

Postoperative analgesia in children when using clonidine or fentanyl with ropivacaine given caudally

Directory of Open Access Journals (Sweden)

Usha Shukla

2011-01-01

Full Text Available Background: The aim of the study was to compare the efficacy of clonidine and fentanyl as an additive to ropivacaine given via single shot caudal epidural in pediatric patients for postoperative pain relief. Materials and Methods: In the present double blind study, 90 children of ASA-I-II aged 3-8 years scheduled for infraumblical surgical procedures were randomly allocated to two groups to receive either ropivacaine 0.25% 1 ml/kg+clonidine 2 μg/kg (group I or ropivacaine 0.25% 1 μl/kg+fentanyl 1 μg/kg (group II. Caudal block was performed after the induction of general anesthesia. Postoperatively patients were observed for analgesia, sedation, hemodynamics, and side effects/complications. Results: Both the groups were similar with respect to patient and various block characteristics. The analgesic properties and hemodynamics were also comparable in both groups (P > 0.05. Side effects such as respiratory depression, vomiting bradycardia were significantly less in group I than group II (P < 0.05 ensuing more patient comfort. Conclusions: The analgesic properties of clonidine and fentanyl as additives to ropivacaine in single shot caudal epidural in children are comparable but clonidine offers a more favorable side effect profile. The use of clonidine as additive to ropivacaine in caudal epidural is superior choice to fentanyl because of lack of unwanted side effects and increased patient comfort.

Caudal ecológico del río Chambas en la provincia Ciego de Ávila

OpenAIRE

Brown Manrique, Oscar; Gallardo Ballat, Yurisbel; Williams Harriote, Patricio W.; Torres Martínez, Yuneisi

2016-01-01

La investigación se desarrolló en el río Chambas de la provincia Ciego de Ávila con el objetivo de determinar el caudal ecológico mediante cinco metodologías: Curva de Permanencia de Caudales, Rafael Heras, Tennant, Franquet y Perímetro Mojado. Se analizó una serie de 21 años de gastos medios mensuales en el periodo comprendido de 1976 al 1986, obtenidos de la estación hidrométrica Puente Circuito Norte. Los principales resultados demostraron que los caudales promedios del río Chambas present...

Caudal Regression and Encephalocele: Rare Manifestations of Expanded Goldenhar Complex

Directory of Open Access Journals (Sweden)

Gabriella D’Angelo

2017-01-01

Full Text Available Oculoauriculovertebral spectrum, or Goldenhar Syndrome, is a condition characterized by variable degrees of uni- or bilateral involvement of craniofacial structures, ocular anomalies, and vertebral defects. Its expressivity is variable; therefore, the term “expanded Goldenhar complex” has been coined. The Goldenhar Syndrome usually involves anomalies in craniofacial structures, but it is known that nervous system anomalies, including encephalocele or caudal regression, may, rarely, occur in this condition. We report two rare cases of infants affected by Goldenhar Syndrome, associated with neural tube defects, specifically caudal regression syndrome and nasal encephaloceles, to underline the extremely complex and heterogeneous clinical features of this oculoauriculovertebral spectrum. These additional particular cases could increase the number of new variable spectrums to be included in the “expanded Goldenhar complex.”

Caudal Regression Syndrome with Partial Agenesis of the Corpus callosum and Partial Lobar Holoprosencephaly

Science.gov (United States)

Hashami, Hilal Al; Bataclan, Maria F; Mathew, Mariam; Krishnan, Lalitha

2010-01-01

Caudal regression syndrome is a rare fetal condition of diabetic pregnancy. Although the exact mechanism is not known, hyperglycaemia during embryogenesis seems to act as a teratogen. Independently, caudal regression syndrome (CRS), agenesis of the corpus callosum (ACC) and partial lobar holoprosencephaly (HPE) have been reported in infants of diabetic mothers. To our knowledge, a combination of all these three conditions has not been reported so far. PMID:21509087

Comparing caudal and penile nerve blockade using bupivacaine in ...

African Journals Online (AJOL)

Background: Caudal anaesthesia is recommended for most surgical procedures of the lower part of the body, mainly below the umbilicus. It has been well established that a dorsal penile nerve block immediately after surgery decreases postoperative pain in children undergoing hypospadias repair. This study aimed to ...

Lateral prefrontal cortex is organized into parallel dorsal and ventral streams along the rostro-caudal axis.

Science.gov (United States)

Blumenfeld, Robert S; Nomura, Emi M; Gratton, Caterina; D'Esposito, Mark

2013-10-01

Anatomical connectivity differences between the dorsal and ventral lateral prefrontal cortex (PFC) of the non-human primate strongly suggests that these regions support different functions. However, after years of study, it remains unclear whether these regions are functionally distinct. In contrast, there has been a groundswell of recent studies providing evidence for a rostro-caudal functional organization, along the lateral as well as dorsomedial frontal cortex. Thus, it is not known whether dorsal and ventral regions of lateral PFC form distinct functional networks and how to reconcile any dorso-ventral organization with the medio-lateral and rostro-caudal axes. Here, we used resting-state connectivity data to identify parallel dorsolateral and ventrolateral streams of intrinsic connectivity with the dorsomedial frontal cortex. Moreover, we show that this connectivity follows a rostro-caudal gradient. Our results provide evidence for a novel framework for the intrinsic organization of the frontal cortex that incorporates connections between medio-lateral, dorso-ventral, and rostro-caudal axes.

Computed tomography in the evaluation of caudal cervical spondylomyelopathy of the Doberman Pinscher

International Nuclear Information System (INIS)

Sharp, N.J.H.; Cofone, M.; Robertson, I.D.; DeCarlo, A.; Smith, G.K.; Thrall, D.E.

1995-01-01

Caudal cervical spondylomyelopathy is a common neurologic disorder of Doberman pinschers which has a number of striking similarities to cervical spondylotic myelopathy in humans. Diagnosis of this human disease is facilitated considerably by the use of computed tomographic (CT) myelography. Sixteen Doberman pinscher dogs with caudal cervical spondylomyelopathy were studied by conventional myelography followed by CT myelography. A close correlation was noted between the CT myelographic appearance of the cervical spinal cord in these dogs, and that reported for human cervical spondylotic myelopathy. Five dogs had atrophy of the spinal cord, and in another there was an accumulation of contrast medium within the spinal cord. These features are often associated with a poor response to surgical decompression in humans with cervical spondylotic myelopathy. The CT examination provided information that could not be obtained by conventional myelography alone and should be considered as an additional diagnostic procedure in dogs with caudal cervical spondylomyelopathy

Sensory nerve conduction in the caudal nerves of rats with diabetes Condução nervosa sensorial no nervo caudal de ratos com diabetes experimental

Directory of Open Access Journals (Sweden)

Celina Cordeiro de Carvalho

2011-04-01

Full Text Available PURPOSE: To investigate sensory nerve conduction of the caudal nerve in normal and diabetic rats. METHODS: Diabetes was induced in twenty 8-weeks old Wistar male rats. Twenty normal rats served as controls. Caudal nerve conduction studies were made before diabetes induction and the end of each week for six consecutive weeks. The caudal nerve was stimulated distally and nerve potentials were recorded proximally on the animal's tail using common "alligator" clips as surface electrodes. RESULTS: After induction, nerve conduction velocities (NCV increased slower in the diabetic than in the control group. Sensory nerve action potentials (SNAP conduction velocities increased slower in the diabetic than in the control group (slope of regression line: 0.5 vs 1.3m/s per week; NCV in the 15th week = 39±3m/s vs 44±4m/s. Tukey's tests showed differences between groups at the 11th, 13th and 15th weeks old. From the 10th week on, SNAP amplitudes increased faster in the diabetic than in the control group (slopes of the regression line: 10 vs 8µV per week; SNAP amplitudes in the 15th week: 107±23µV vs 85±13µV. Differences at the 12th, 13th and 15th weeks were significant. CONCLUSION: In diabetic rats nerve conduction velocities were slower whereas amplitudes were larger than in normal rats.OBJETIVO: Investigar a condução nervosa sensorial do nervo caudal em ratos normais e diabéticos. MÉTODOS: O diabetes foi induzido em vinte ratos Wistar com idade de oito semanas. Vinte ratos serviram como controle. Os estudos da condução do nervo caudal foram feitos antes da indução do diabetes e ao final de cada semana, durante seis semanas consecutivas. O nervo caudal foi estimulado distalmente e potenciais foram registrados proximalmente na cauda do animal, usando clipes comuns "jacaré" como eletrodos de superfície. RESULTADOS: Após a indução, a velocidade de condução nervosa (VCN aumentou mais lentamente no grupo diabético que no controle

Comparison of caudal bupivacaine and bupivacaine-tramadol for postoperative analgesia in children with hypospadias repair

International Nuclear Information System (INIS)

Khan, S.; Memon, M.I.

2008-01-01

To compare the effects after caudal bupivacaine alone and bupivacaine-tramadol in young children with hypospadias repair. Randomized controlled trial. Sixty children aged between 13-53 months coming for hypospadias repair were divided randomly into two groups A and B. A caudal block was performed immediately after induction of general anaesthesia. The patients in group A received 0.125% bupivacaine 1 ml/kg with tramadol 1 mg/kg body weight caudally. Group B patients received 0.25% bupivacaine 1 ml/kg body weight caudally. Anaesthesia was discontinued after completion of surgery. In the recovery area, ventilatory frequency and pain scores were recorded at 1 hourly interval for first 6 hours and then every 2 hours for next 6 hours postoperatively. A modified TPPPS (Toddler-Preschool Postoperative Pain Scale) was used to assess the pain. Episodes of vomiting, facial flush and pruritus were noted, if present. The duration of analgesia was significantly prolonged in group A patients (p-value=0.001). A low frequency of postoperative vomiting was observed in both groups i.e. 10% in group A and 6.66% in group B (p-value=0.64). No respiratory depression, flushing and pruritus were observed. Low dose combination of bupivacaine and tramadol, when administered caudally, had an additive effect and provided prolonged and effective postoperative analgesia with minimal side effects. The risk of toxicity from bupivacaine decreased when combined with tramadol in low doses. (author)

Prediction of slant path rain attenuation statistics at various locations

Science.gov (United States)

Goldhirsh, J.

1977-01-01

The paper describes a method for predicting slant path attenuation statistics at arbitrary locations for variable frequencies and path elevation angles. The method involves the use of median reflectivity factor-height profiles measured with radar as well as the use of long-term point rain rate data and assumed or measured drop size distributions. The attenuation coefficient due to cloud liquid water in the presence of rain is also considered. Absolute probability fade distributions are compared for eight cases: Maryland (15 GHz), Texas (30 GHz), Slough, England (19 and 37 GHz), Fayetteville, North Carolina (13 and 18 GHz), and Cambridge, Massachusetts (13 and 18 GHz).

Electrophysical properties, synaptic transmission and neuromodulation in serotonergic caudal raphe neurons.

Science.gov (United States)

Li, Y W; Bayliss, D A

1998-06-01

1. We studied electrophysiological properties, synaptic transmission and modulation by 5-hydroxytryptamine (5-HT) of caudal raphe neurons using whole-cell recording in a neonatal rat brain slice preparation; recorded neurons were identified as serotonergic by post-hoc immunohistochemical detection of tryptophan hydroxylase, the 5-HT-synthesizing enzyme. 2. Serotonergic neurons fired spontaneously (approximately 1 Hz), with maximal steady state firing rates of < 4 Hz. 5-Hydroxytryptamine caused hyperpolarization and cessation of spike activity in these neurons by activating inwardly rectifying K+ conductance via somatodendritic 5-HT1A receptors. 3. Unitary glutamatergic excitatory post-synaptic potentials (EPSP) and currents (EPSC) were evoked in serotonergic neurons by local electrical stimulation. Evoked EPSC were potently inhibited by 5-HT, an effect mediated by presynaptic 5-HT1B receptors. 4. In conclusion, serotonergic caudal raphe neurons are spontaneously active in vitro; they receive prominent glutamatergic synaptic inputs. 5-Hydroxytryptamine regulates serotonergic neuronal activity of the caudal raphe by decreasing spontaneous activity via somatodendritic 5-HT1A receptors and by inhibiting excitatory synaptic transmission onto these neurons via presynaptic 5-HT1B receptors. These local modulatory mechanisms provide multiple levels of feedback autoregulation of serotonergic raphe neurons by 5-HT.

Comparison of results of medial rectus muscle recession using augmentation, Faden procedure, and slanted recession in the treatment of high accommodative convergence/accommodation ratio esotropia.

Science.gov (United States)

Gharabaghi, Davoud; Zanjani, Leila Kazemi

2006-01-01

According to the literature, accommodative esotropia has an unpredictable course when nonsurgical treatment is considered, especially in cases with a high accommodative convergence/accommodation ratio (AC/A). The aim of this study was to compare the results of augmented recession, slanted recession, and recession with posterior fixation suture of the medial rectus muscles in the treatment of high AC/A esotropia. Twenty-eight children (4 to 14 years old) with high AC/A esotropia with a near-distance disparity greater than 10 PD were included in a prospective, randomized, blinded clinical trial. Nine children underwent recession of both medial rectus muscles and posterior fixation suture (Faden procedure), 9 children underwent augmented recession of the medial rectus muscles, and 10 children underwent slanted recession of both medial rectus muscles. The amount of esodeviation was measured before strabismus surgery and at least 6 months postoperatively. In the augmented recession group, the mean near-distance disparity was reduced from 16.33 +/- 2.17 PD preoperatively to 7.55 +/- 3.87 PD postoperatively (54.21%; P = .056). In the Faden procedure group, it was reduced from 15.22 +/- 4.08 PD to 2.55 +/- 4.03 PD (80.7%; P = .056). In the slanted recession group, it was reduced from 15.50 +/- 4.30 PD to 4.10 +/- 4.80 PD (67.55%; P = .056). The Faden procedure had the best outcome, but slanted recession also was successful. Because of our good results and an easy, non-invasive approach without any additional complications, we recommend slanted recession to treat high AC/A esotropia.

Regionalizacion de caudales mensuales en la región hidrográfica del Titicaca Puno Perú

OpenAIRE

Lujano Laura, Apolinario; Autoridad Nacional del Agua – Perú; Quispe Aragón, José Pitágoras; Autoridad Nacional del Agua – Perú; Lujano Laura, Efraín; Universidad Peruana Unión – Perú

2017-01-01

RESUMENLa presente investigación se realizó en la Región Hidrográfica del Titicaca, Perú. El objetivo principal fue desarrollar modelos regionales de caudales medios mensuales y de persistencia de los principales ríos, aplicado a la problemática de la estimación de caudales en cuencas sin registro hidrométrico. Se tomaron como variables independientes las características climáticas y fisiográficas de las cuencas en estudio y como variable dependiente los caudales medios mensuales y de persist...

Characterization of Vadose Zone Sediment: Slant Borehole SX-108 in the S-SX Waste Management Area

International Nuclear Information System (INIS)

Serne, R. Jeffrey; Last, George V.; Schaef, Herbert T.; Lanigan, David C.; Lindenmeier, Clark W.; Ainsworth, Calvin C.; Clayton, Ray E.; Legore, Virginia L.; O'Hara, Matthew J.; Brown, Christopher F.; Orr, Robert D.; Kutnyakov, Igor V.; Wilson, Teresa C.; Wagnon, Kenneth B.; Williams, Bruce A.; Burke, Deborah S.

2008-01-01

This report was revised in September 2008 to remove acid-extractable sodium data from Table 4.17. The sodium data was removed due to potential contamination introduced during the acid extraction process. The rest of the text remains unchanged from the original report issued in February 2002. The overall goal of the of the Tank Farm Vadose Zone Project, led by CH2M HILL Hanford Group, Inc., is to define risks from past and future single-shell tank farm activities. To meet this goal, CH2M HILL Hanford Group, Inc., asked scientists from Pacific Northwest National Laboratory to perform detailed analyses on vadose zone sediment from within the S-SX Waste Management Area. This report is the fourth in a series of four reports to present the results of these analyses. Specifically, this report contains all the geologic, geochemical, and selected physical characterization data collected on vadose zone sediment recovered from a slant borehole installed beneath tank SX-108 (or simply SX-108 slant borehole)

Characterization of Vadose Zone Sediment: Slant Borehole SX-108 in the S-SX Waste Management Area

Energy Technology Data Exchange (ETDEWEB)

Serne, R. Jeffrey; Last, George V.; Schaef, Herbert T.; Lanigan, David C.; Lindenmeier, Clark W.; Ainsworth, Calvin C.; Clayton, Ray E.; Legore, Virginia L.; O' Hara, Matthew J.; Brown, Christopher F.; Orr, Robert D.; Kutnyakov, Igor V.; Wilson, Teresa C.; Wagnon, Kenneth B.; Williams, Bruce A.; Burke, Deborah S.

2008-09-11

This report was revised in September 2008 to remove acid-extractable sodium data from Table 4.17. The sodium data was removed due to potential contamination introduced during the acid extraction process. The rest of the text remains unchanged from the original report issued in February 2002. The overall goal of the of the Tank Farm Vadose Zone Project, led by CH2M HILL Hanford Group, Inc., is to define risks from past and future single-shell tank farm activities. To meet this goal, CH2M HILL Hanford Group, Inc., asked scientists from Pacific Northwest National Laboratory to perform detailed analyses on vadose zone sediment from within the S-SX Waste Management Area. This report is the fourth in a series of four reports to present the results of these analyses. Specifically, this report contains all the geologic, geochemical, and selected physical characterization data collected on vadose zone sediment recovered from a slant borehole installed beneath tank SX-108 (or simply SX-108 slant borehole).

Evaluation of gradual occlusion of the caudal vena cava in clinically normal dogs.

Science.gov (United States)

Peacock, John T; Fossum, Theresa W; Bahr, Anne M; Miller, Matthew W; Edwards, John F

2003-11-01

To devise a technique for gradual occlusion of the caudal vena cava in dogs and determine effects of complete occlusion of the caudal vena cava. 8 mixed-breed hounds that weighed between 25 and 30 kg. Baseline evaluation of dogs included serum biochemical analyses and determination of glomerular filtration rate (GFR) with dynamic renal scintigraphy and plasma clearance analysis. An occluder was placed around the vena cava in the region cranial to the renal veins. The occluder was attached to a vascular access port. The vena cava was gradually occluded over 2 weeks. The GFR was measured every 2 weeks after surgery, and venograms were performed every 3 weeks after surgery. Blood samples were collected every 48 hours for the first week and then weekly thereafter to measure BUN and creatinine concentrations and activities of alanine transaminase, alkaline phosphatase, and creatinine kinase. Dogs were euthanatized 6 weeks after surgery, and tissues were submitted for histologic examination. The GFR and biochemical data were compared with baseline values. Gradual occlusion of the caudal vena cava was easily and consistently performed with this method, and adverse clinical signs were not detected. Formation of collateral vessels allowed overall GFR to remain constant despite a decrease in function of the left kidney. Measured biochemical values did not deviate from reference ranges. Gradual occlusion of the caudal vena cava may allow removal of adrenal gland tumors with vascular invasion that would otherwise be difficult or impossible to resect.

Organ and Effective Dose Coefficients for Cranial and Caudal Irradiation Geometries: Neutrons

Science.gov (United States)

Veinot, K. G.; Eckerman, K. F.; Hertel, N. E.; Hiller, M. M.

2017-09-01

With the introduction of new recommendations by ICRP Publication 103, the methodology for determining the protection quantity, effective dose, has been modified. The modifications include changes to the defined organs and tissues, the associated tissue weighting factors, radiation weighting factors, and the introduction of reference sex-specific computational phantoms (ICRP Publication 110). Computations of equivalent doses in organs and tissues are now performed in both the male and female phantoms and the sex-averaged values used to determine the effective dose. Dose coefficients based on the ICRP 103 recommendations were reported in ICRP Publication 116, the revision of ICRP Publication 74 and ICRU Publication 57. The coefficients were determined for the following irradiation geometries: anterior-posterior (AP), posterior-anterior (PA), right and left lateral (RLAT and LLAT), rotational (ROT), and isotropic (ISO). In this work, the methodology of ICRP Publication 116 was used to compute dose coefficients for neutron irradiation of the body with parallel beams directed upward from below the feet (caudal) and directed downward from above the head (cranial). These geometries may be encountered in the workplace from personnel standing on contaminated surfaces or volumes and from overhead sources. Calculations of organ and tissue absorbed doses for caudal and cranial exposures to neutrons ranging in energy from 10-9 MeV to 10 GeV have been performed using the MCNP6 radiation transport code and the adult reference voxel phantoms of ICRP Publication 110. At lower energies the effective dose per particle fluence for cranial and caudal exposures is less than AP orientations while above about 30 MeV the cranial and caudal values are greater.

Evaluation of caudal dexamethasone with ropivacaine for post-operative analgesia in paediatric herniotomies: A randomised controlled study

Directory of Open Access Journals (Sweden)

Santosh Choudhary

2016-01-01

Full Text Available Background and Aims: Caudal analgesia is one of the most popular regional blocks in paediatric patients undergoing infra-umbilical surgeries but with the drawback of short duration of action after single shot local anaesthetic injection. We evaluated whether caudal dexamethasone 0.1 mg/kg as an adjuvant to the ropivacaine improved analgesic efficacy after paediatric herniotomies. Methods: Totally 128 patients of 1–5 years age group, American Society of Anaesthesiologists physical status I and II undergoing elective inguinal herniotomy were randomly allocated to two groups in double-blind manner. Group A received 1 ml/kg of 0.2% ropivacaine caudally and Group B received 1 ml/kg of 0.2% ropivacaine, in which 0.1 mg/kg dexamethasone was added for caudal analgesia. Post operative pain by faces, legs, activity, cry and consolability tool score, rescue analgesic requirement and adverse effects were noted for 24 h. Results: Results were statistically analysed using Student's t-test. Pain scores measured at 1, 2, 4, and 6 h post-operative, were lower in Group B as compared to Group A. Mean duration of analgesia in Group A was 248.4 ± 54.1 min and in Group B was 478.046 ± 104.57 min with P = 0.001. Rescue analgesic requirement was more in Group A as compared to Group B. Adverse effects after surgery were comparable between the two groups. Conclusion: Caudal dexamethasone added to ropivacaine is a good alternative to prolong post-operative analgesia with less pain score compared to caudal ropivacaine alone.

Comparative study of caudal bupivacaine versus bupivacaine with tramadol for postoperative analgesia in paediatric cancer patients

Institute of Scientific and Technical Information of China (English)

Mohammed Hegazy; Ayman A. Ghoneim

2013-01-01

Objective: Caudal epidural analgesia has become very common analgesic technique in paediatric surgery. Add-ing tramadol to bupivacaine for caudal injection prolongs duration of analgesia with minimal side effects. The aim of the study was to investigate the different effects of caudal bupivacaine versus bupivacaine with thamadol for postoperative analgesia in paediatric cancer patients. Methods: A prospective randomized controlled trial was conducted over 40 paediatric cancer pa-tients who were recruited from Children Cancer Hospital of Egypt (57357 Hospital). Patients were randomized into 2 groups: bupivacaine group (group B, 20 patients) to receive single shot caudal block of 1 mL/kg 0.1875% bupivacaine; tramadol group (group T, 20 patients) prepared as group B with the addition of 1 mg/kg caudal tramadol. Results: The mean duration of analgesia was significantly longer among group T than group B [(24 ± 13.7) hours versus (7 ± 3.7) hours respectively with P = 0.001]. Group T showed a significantly lower mean FLACC score than group B (2.2 ± 0.9 versus 3.6 ± 0.6 with P = 0.002). The difference in FLACC score was comparable on arrival, and after 2 and 4 hours. At 8 and 12 hours the group B recorded significantly higher scores (P = 0.002 and 0.0001 respectively). There were no significant differences between the groups as regards sedation score [the median in both groups was 1 (0–1) with P value = o.8]. No one developed facial flush or pruritis. Conclusion: Caudal injection of low dose tramadol 1 mg/kg with bupivacaine 0.1875% is proved to be effective, long standing technique for postoperative analgesia in major paediatric cancer surgery and almost devoid of side effect.

Evaluation of Anesthesia Profile in Pediatric Patients after Inguinal Hernia Repair with Caudal Block or Local Wound Infiltration

Directory of Open Access Journals (Sweden)

Aleksandra Gavrilovska-Brzanov

2016-02-01

CONCLUSIONS: Between children undergoing inguinal hernia repair, local wound infiltration insures safety and satisfactory analgesia for surgery. Compared to caudal block it is not overwhelming. Caudal block provides longer analgesia, however complications are rather common.

Application of ray-traced tropospheric slant delays to geodetic VLBI analysis

Science.gov (United States)

Hofmeister, Armin; Böhm, Johannes

2017-08-01

The correction of tropospheric influences via so-called path delays is critical for the analysis of observations from space geodetic techniques like the very long baseline interferometry (VLBI). In standard VLBI analysis, the a priori slant path delays are determined using the concept of zenith delays, mapping functions and gradients. The a priori use of ray-traced delays, i.e., tropospheric slant path delays determined with the technique of ray-tracing through the meteorological data of numerical weather models (NWM), serves as an alternative way of correcting the influences of the troposphere on the VLBI observations within the analysis. In the presented research, the application of ray-traced delays to the VLBI analysis of sessions in a time span of 16.5 years is investigated. Ray-traced delays have been determined with program RADIATE (see Hofmeister in Ph.D. thesis, Department of Geodesy and Geophysics, Faculty of Mathematics and Geoinformation, Technische Universität Wien. http://resolver.obvsg.at/urn:nbn:at:at-ubtuw:1-3444, 2016) utilizing meteorological data provided by NWM of the European Centre for Medium-Range Weather Forecasts (ECMWF). In comparison with a standard VLBI analysis, which includes the tropospheric gradient estimation, the application of the ray-traced delays to an analysis, which uses the same parameterization except for the a priori slant path delay handling and the used wet mapping factors for the zenith wet delay (ZWD) estimation, improves the baseline length repeatability (BLR) at 55.9% of the baselines at sub-mm level. If no tropospheric gradients are estimated within the compared analyses, 90.6% of all baselines benefit from the application of the ray-traced delays, which leads to an average improvement of the BLR of 1 mm. The effects of the ray-traced delays on the terrestrial reference frame are also investigated. A separate assessment of the RADIATE ray-traced delays is carried out by comparison to the ray-traced delays from the

Caudal dysgenesis and sirenomelia-single centre experience suggests common pathogenic basis.

Science.gov (United States)

Thottungal, Anjana D; Charles, Adrian K; Dickinson, Jan E; Bower, Carol

2010-10-01

Abnormally formed lower limbs with varying degrees of fusion are the major feature of sirenomelia whereas maldeveloped lower limbs without fusion are found in association with caudal dysgenesis (CD). The relationship between these two entities has been a topic of debate for many years. The presence of a single umbilical artery originating from the abdominal aorta was considered a major feature distinguishing sirenomelia from CD. Based on this finding, the vascular steal theory was put forward as the causative mechanism of sirenomelia. CD and sirenomelia were considered to be two entirely different entities with distinct pathogenic mechanisms. However, it is now clear that a single umbilical artery can be found in some patients of CD and normal umbilical arteries in some patients of sirenomelia. The hypothesis of primary deficiency of caudal mesoderm caused by early developmental disruption suggests that sirenomelia and CD are two ends of a spectrum of maldevelopment of caudal mesoderm. In this paper we report on the clinical and pathological features of 16 patients of CD and 9 patients of sirenomelia from our institution and review the literature. This series of cases is notable for the significant association with neural tube defects, refining the renal and urogenital pathology associated with these conditions, and supporting the concept of a continuum of the disease spectrum. Copyright © 2010 Wiley-Liss, Inc.

Accurate acoustic and elastic beam migration without slant stack for complex topography

International Nuclear Information System (INIS)

Huang, Jianping; Yuan, Maolin; Li, Zhenchun; Liao, Wenyuan; Yue, Yubo

2015-01-01

Recent trends in seismic exploration have led to the collection of more surveys, often with multi-component recording, in onshore settings where both topography and subsurface targets are complex, leading to challenges for processing methods. Gaussian beam migration (GBM) is an alternative to single-arrival Kirchhoff migration, although there are some issues resulting in unsatisfactory GBM images. For example, static correction will give rise to the distortion of wavefields when near-surface elevation and velocity vary rapidly. Moreover, Green’s function compensated for phase changes from the beam center to receivers is inaccurate when receivers are not placed within some neighborhood of the beam center, that is, GBM is slightly inflexible for irregular acquisition system and complex topography. As a result, the differences of both the near-surface velocity and the surface slope from the beam center to the receivers and the poor spatial sampling of the land data lead to inaccuracy and aliasing of the slant stack, respectively. In order to improve the flexibility and accuracy of GBM, we propose accurate acoustic, PP and polarity-corrected PS beam migration without slant stack for complex topography. The applications of this method to one-component synthetic data from a 2D Canadian Foothills model and a Zhongyuan oilfield fault model, one-component field data and an unseparated multi-component synthetic data demonstrate that the method is effective for structural and relatively amplitude-preserved imaging, but significantly more time-consuming. (paper)

Systematization, distribution and territory of the caudal cerebral artery on the brain's surface of the turkey (Meleagris gallopavo

Directory of Open Access Journals (Sweden)

Amarílis Díaz de Carvalho

2014-10-01

Full Text Available Thirty Meleagris gallopavo heads with their neck segments were used. Animals were contained and euthanized with the association of mebezonium iodide, embutramide and tetracaine hydrochloride (T 61, Intervet by intravenous injection. The arterial system was rinsed with cold saline solution (15°C, with 5000IU heparin and filled with red-colored latex. The samples were fixed in 20% formaldehyde for seven days. The brains were removed with a segment of cervical spinal cord and after, the dura-mater was removed and the arteries dissected. The cerebral carotid arteries, after the intercarotid anastomosis, were projected around the hypophysis, until they reached the tuber cinereum and divided into their terminal branches, the caudal branch and the rostral branch. The rostral branch was projected rostrolateralwards and gave off, in sequence, two collateral branches, the caudal cerebral and the middle cerebral arteries and the terminal branch was as cerebroethmoidal artery. The caudal cerebral artery of one antimere formed the interhemispheric artery, which gave off dorsal hemispheric branches to the convex surface of both antimeres. Its dorsal tectal mesencephalic branch, of only one antimere, originated the dorsal cerebellar artery. In the interior of the cerebral transverse fissure, after the origin of the dorsal tectal mesencephalic artery, the caudal cerebral artery emitted occipital hemispheric branches, pineal branches and medial hemispheric branches, on both antimeres. The caudal cerebral artery's territory comprehended the entire surface of the dorsal hemioptic lobe, the rostral surface of the cerebellum, the diencephalic structures, the caudal pole and the medial surface of the cerebral hemisphere and in the convex surface, the sagittal eminence except for its most rostral third. Due to the asymmetry found in the caudal cerebral arteries' ramifications, the models were classified into three types and their respective subtypes.

Caudal block and emergence delirium in pediatric patients: Is it analgesia or sedation?

Directory of Open Access Journals (Sweden)

Aparna Sinha

2012-01-01

Full Text Available Background: Emergence delirium (ED although a short-lived and self-limiting phenomenon, makes a child prone to injury in the immediate postoperative period and hence is a cause of concern not only to the pediatric anesthesiologist, surgeons, and post anesthesia care unit staff but also amongst parents. Additional medication to quieten the child offsets the potential benefits of rapid emergence and delays recovery in day care settings. There is conflicting evidence of influence of analgesia and sedation following anesthesia on emergence agitation. We hypothesized that an anesthetic technique which improves analgesia and prolongs emergence time will reduce the incidence of ED. We selected ketamine as adjuvant to caudal block for this purpose. Methods: This randomized, double blind prospective study was performed in 150 premedicated children ASA I, II, aged 2 to 8 years who were randomly assigned to either group B (caudal with bupivacaine, BK (bupivacaine and ketamine, or NC (no caudal, soon after LMA placement. Recovery characteristics and complications were recorded. Results: Emergence time, duration of pain relief, and Pediatric Anesthesia Emergence Delirium (PAED scores were significantly higher in the NC group (P<0.05. Duration of analgesia and emergence time were significantly more in group BK than groups B and NC. However, the discharge readiness was comparable between all groups. No patient in BK group required to be given any medication to treat ED. Conclusion: Emergence time as well as duration of analgesia have significant influence on incidence of emergence delirium. Ketamine, as caudal adjuvant is a promising agent to protect against ED in children, following sevoflurane anesthesia.

Metameric pattern of intervertebral disc/vertebral body is generated independently of Mesp2/Ripply-mediated rostro-caudal patterning of somites in the mouse embryo.

Science.gov (United States)

Takahashi, Yu; Yasuhiko, Yukuto; Takahashi, Jun; Takada, Shinji; Johnson, Randy L; Saga, Yumiko; Kanno, Jun

2013-08-15

The vertebrae are derived from the sclerotome of somites. Formation of the vertebral body involves a process called resegmentation, by which the caudal half of a sclerotome is combined with the rostral half of the next sclerotome. To elucidate the relationship between resegmentation and rostro-caudal patterning of somite, we used the Uncx4.1-LacZ transgene to characterize the resegmentation process. Our observations suggested that in the thoracic and lumbar vertebrae, the Uncx4.1-expressing caudal sclerotome gave rise to the intervertebral disc (IVD) and rostral portion of the vertebral body (VB). In the cervical vertebrae, the Uncx4.1-expressing caudal sclerotome appeared to contribute to the IVD and both caudal and rostral ends of the VB. This finding suggests that the rostro-caudal gene expression boundary does not necessarily coincide with the resegmentation boundary. This conclusion was supported by analyses of Mesp2 KO and Ripply1/2 double KO embryos lacking rostral and caudal properties, respectively. Resegmentation was not observed in Mesp2 KO embryos, but both the IVD and whole VB were formed from the caudalized sclerotome. Expression analysis of IVD marker genes including Pax1 in the wild-type, Mesp2 KO, and Ripply1/2 DKO embryos also supported the idea that a metameric pattern of IVD/VB is generated independently of Mesp2/Ripply-mediated rostro-caudal patterning of somite. However, in the lumbar region, IVD differentiation appeared to be stimulated by the caudal property and suppressed by the rostral property. Therefore, we propose that rostro-caudal patterning of somites is not a prerequisite for metameric patterning of the IVD and VB, but instead required to stimulate IVD differentiation in the caudal half of the sclerotome. Copyright © 2013 Elsevier Inc. All rights reserved.

Organ and effective dose coefficients for cranial and caudal irradiation geometries: photons

International Nuclear Information System (INIS)

Veinot, K.G.; Eckerman, K.F.; Hertel, N.E.

2016-01-01

With the introduction of new recommendations of the International Commission on Radiological Protection (ICRP) in Publication 103, the methodology for determining the protection quantity, effective dose, has been modified. The modifications include changes to the defined organs and tissues, the associated tissue weighting factors, radiation weighting factors and the introduction of reference sex-specific computational phantoms. Computations of equivalent doses in organs and tissues are now performed in both the male and female phantoms and the sex-averaged values used to determine the effective dose. Dose coefficients based on the ICRP 103 recommendations were reported in ICRP Publication 116, the revision of ICRP Publication 74 and ICRU Publication 57. The coefficients were determined for the following irradiation geometries: anterior-posterior (AP), posterior-anterior (PA), right and left lateral (RLAT and LLAT), rotational (ROT) and isotropic (ISO). In this work, the methodology of ICRP Publication 116 was used to compute dose coefficients for photon irradiation of the body with parallel beams directed upward from below the feet (caudal) and directed downward from above the head (cranial). These geometries may be encountered in the workplace from personnel standing on contaminated surfaces or volumes and from overhead sources. Calculations of organ and tissue kerma and absorbed doses for caudal and cranial exposures to photons ranging in energy from 10 keV to 10 GeV have been performed using the MCNP6.1 radiation transport code and the adult reference phantoms of ICRP Publication 110. As with calculations reported in ICRP 116, the effects of charged-particle transport are evident when compared with values obtained by using the kerma approximation. At lower energies the effective dose per particle fluence for cranial and caudal exposures is less than AP orientations while above ∼30 MeV the cranial and caudal values are greater. (authors)

Unusual caudal vena cava thrombosis in a cow, secondary to Trueperella (Arcanobacterium pyogenes infection

Directory of Open Access Journals (Sweden)

Rodrigo Garcia Motta

Full Text Available Abstract: The caudal vena cava thrombosis, or pulmonary thromboembolism, in cattle is correlated with lactic acidosis, caused by diets rich in grains and highly fermentable, associated or not to septic situations, used in feedlots of beef or high-producing dairy cattle. This paper reports an unusual caudal vena cava thrombosis in a cow, secondary to Trueperella (Arcanobacterium pyogenes infection, resulting in reduced milk production, anorexia, pale mucous membranes, ruminal atony, sternal decubitus and autoauscultation position. The heart was enlarged at necropsy, presence of clots distributed along the thoracic cavity, adherence between lung and pleura, abscesses, emphysema, petechiae, suffusions and ecchymosis in lungs, thickening of the caudal vena cava wall, hepatomegaly with chronic passive congestion ("nutmeg" aspect, and rumenitis. In lab, the actinomycete Trueperella (Arcanobacterium pyogenes was isolated from liver and lung samples, probably resulting through dissemination of the bacteria of the rumen content, what reaffirms the opportunistic behavior of this actinomycete.

Plasma concentrations and pharmacokinetics of bupivacaine with and without adrenaline following caudal anaesthesia in infants

DEFF Research Database (Denmark)

Hansen, Tom Giedsing; Morton, N S; Cullen, P M

2001-01-01

The aim of this study was to determine whether the use of adrenaline 1/400000 added to 0.25% bupivacaine significantly delays the systemic absorption of the drug from the caudal epidural space in young infants.......The aim of this study was to determine whether the use of adrenaline 1/400000 added to 0.25% bupivacaine significantly delays the systemic absorption of the drug from the caudal epidural space in young infants....

Efficacy of clonidine as an adjuvant to bupivacaine for caudal analgesia in children undergoing sub-umbilical surgery

Directory of Open Access Journals (Sweden)

Aruna Parameswari

2010-01-01

Full Text Available Caudal epidural analgesia with bupivacaine is very popular in paediatric anaesthesia for providing intra- and postoperative analgesia. Several adjuvants have been used to prolong the action of bupivacaine. We evaluated the efficacy of clonidine added to bupivacaine in prolonging the analgesia produced by caudal bupivacaine in children undergoing sub-umbilical surgery. One hundred children, age one to three years, undergoing sub-umbilical surgery, were prospectively randomized to one of two groups: caudal analgesia with 1 ml/kg of 0.25% bupivacaine in normal saline (Group A or caudal analgesia with 1 ml/kg of 0.25% bupivacaine with 1 μg/kg of clonidine in normal saline (Group B. Post-operative pain was assessed for 24 hours using the FLACC scale. The mean duration of analgesia was significantly longer in Group B (593.4 ± 423.3 min than in Group A (288.7 ± 259.1 min; P < 0.05. The pain score assessed using FLACC scale was compared between the two groups, and children in Group B had lower pain scores, which was statistically significant. The requirement of rescue medicine was lesser in Group B. Clonidine in a dose of 1 μg/kg added to 0.25% bupivacaine for caudal analgesia, during sub-umbilical surgeries, prolongs the duration of analgesia of bupivacaine, without any side effects.

A Design of Wide Band and Wide Beam Cavity-Backed Slot Antenna Array with Slant Polarization

Directory of Open Access Journals (Sweden)

Huiying Qi

2016-01-01

Full Text Available Design of antenna array under the limitation of restricted size is a challenging problem. Cavity-backed slot antenna is widely used because of its advantages of small size, wide band, and wide beam. In this paper, a design of wide band and wide beam cavity-backed slot antenna array with the slant polarization is proposed. To obtain wide band and wide beam with limited size, the inverted microstrip-fed cavity-backed slot antenna (IMF-CBSA is adopted as the element of 1 × 4 antenna array. The slant polarized antennas and their feeding networks are adopted because of their simple structures. The performance of the proposed antenna array is verified by the simulations and experiments. The measured VSWR < 2 bandwidth is 55% at the center frequency 21.8 GHz, and the gain is larger than 12.2 dB. Experimental results demonstrate that the proposed design achieves wide band and beam with the size of 68 mm × 56 mm × 14.5 mm.

Caudal Regression Syndrome with Partial Agenesis of the Corpus callosum and Partial Lobar Holoprosencephaly: Case report.

Science.gov (United States)

Hashami, Hilal Al; Bataclan, Maria F; Mathew, Mariam; Krishnan, Lalitha

2010-04-01

Caudal regression syndrome is a rare fetal condition of diabetic pregnancy. Although the exact mechanism is not known, hyperglycaemia during embryogenesis seems to act as a teratogen. Independently, caudal regression syndrome (CRS), agenesis of the corpus callosum (ACC) and partial lobar holoprosencephaly (HPE) have been reported in infants of diabetic mothers. To our knowledge, a combination of all these three conditions has not been reported so far.

Incertidumbres en Mediciones de Caudal con Perfiladores de Corriente Acústicos Doppler desde Plataformas Móviles

OpenAIRE

Tarrab, Leticia

2014-01-01

Tesis (DCI)--FCEFN-UNC, 2013 Determina la incertidumbre en las mediciones de caudal con Perfiladores de Corriente Acústicos Doppler (ADCP) desde plataformas móviles a los fines de optimizar las técnicas de medición y elaborar recomendaciones para minimizar los errores (sesgo e incertidumbre aleatoria) en el uso de las técnicas de medición de caudales.

Dinosaur speed demon: the caudal musculature of Carnotaurus sastrei and implications for the evolution of South American abelisaurids.

Directory of Open Access Journals (Sweden)

W Scott Persons

Full Text Available In the South American abelisaurids Carnotaurus sastrei, Aucasaurus garridoi, and, to a lesser extent Skorpiovenator bustingorryi, the anterior caudal ribs project at a high dorsolateral inclination and have interlocking lateral tips. This unique morphology facilitated the expansion of the caudal hypaxial musculature at the expense of the epaxial musculature. Distinct ridges on the ventrolateral surfaces of the caudal ribs of Aucasaurus garridoi are interpreted as attachment scars from the intra caudofemoralis/ilio-ischiocaudalis septa, and confirm that the M. caudofemoralis of advanced South American abelisaurids originated from a portion of the caudal ribs. Digital muscle models indicate that, relative to its overall body size, Carnotaurus sastrei had a substantially larger M. caudofemoralis than any other theropod yet studied. In most non-avian theropods, as in many extant sauropsids, the M. caudofemoralis served as the primary femoral retractor muscle during the locomotive power stroke. This large investment in the M. caudofemoralis suggests that Carnotaurus sastrei had the potential for great cursorial abilities, particularly short-burst sprinting. However, the tightly interlocking morphology of the anterior caudal vertebrae implies a reduced ability to make tight turns. Examination of these vertebral traits in evolutionary context reveals a progressive sequence of increasing caudofemoral mass and tail rigidity among the Abelisauridae of South America.

MODELO AUTORREGRESIVO BILINEAL APLICADO A LA PREDICCIÓN MENSUAL DE CAUDALES EN COLOMBIA

Directory of Open Access Journals (Sweden)

Juan David Cadavid

2013-12-01

Full Text Available Se aplica un modelo estocástico bilineal, el cual inicialmente es propuesto para análisis de retornos financieros y otros sistemas complejos combinando la alta no linealidad y multiplicidad del ruido. Este modelo, por su carácter aleatorio, no tiene componente determinística que permita considerar la persistencia de los caudales en una aplicación a la Hidrología. Por lo tanto, se propone el acoplamiento entre la parte determinística de un modelo autorregresivo de orden 2 y el modelo estocástico bilineal como componente aleatorio, y se obtiene un modelo autorregresivo bilineal (MAB. El MAB se empleó para la predicción de caudales en ventanas de 3, 6 y 12 meses en 12 ríos de Colombia de diferentes regiones del país. El MAB tiene una estructura simple y muestra una mejora sustancial en la disminución de los errores para los caudales máximos y mínimos en el período de validación respecto de los modelos estocásticos tradicionales.

Postoperative Analgesia in Children- Comparative Study between Caudal Bupivacaine and Bupivacaine plus Tramadol

Directory of Open Access Journals (Sweden)

Meena Doda

2009-01-01

Full Text Available Thirty children, ASAI-II, aged between 2yrs-5yrs, undergoing sub umbilical operation (inguinal and penile surgery were selected for this double blind study. They were randomly divided in two groups, group Aand group B. Group A(n15 received 0.25%bupivacaine 0.5ml.kg -1 and Group B (n=15 received 0.25% bupivaeaine 0.5ml.kg -1 and tramadol 2mg.kg -1 as single shot caudal block. Postoperative pain was assessed by a modified TPPPS (Toddler-Preschool Postoperative Pain Scale and analgesic given only when the score was more than 3. In the first 24 hrs it was observed that the mean duration of time interval between the caudal block and first dose of analgesic was significantly long(9. lhrs in Group B as compared to Group A (6.3hrs which was much shorter(p< 0.01.There was no significant haemodynamie changes, motor weakness or respiratory depression in both groups. This study con-cluded that addition of tramadol 2mg.kg -1 to caudal 0.25% bupivacaine 0.5ml.kg -1 significantly prolong the duration of postoperative analgesia in children withoutprodueing much adverse effects.

Comparison of caudal ropivacaine-morphine and paravertebral catheter for major upper abdominal surgery in infants.

Science.gov (United States)

Sato, Makoto; Iida, Takafumi; Kikuchi, Chika; Sasakawa, Tomoki; Kunisawa, Takayuki

2017-05-01

The caudal epidural block is one of the most commonly used regional anesthetic techniques in children. Administration of morphine via caudal injection enables analgesia, even for upper abdominal surgery. The thoracic paravertebral block has also been successfully used to treat perioperative pain during upper abdominal procedures in pediatric patients. In the current study, we compared the two regional techniques for upper abdominal surgery in infants to determine whether one of them was preferable to the other. Consecutive patients under 12 months of age who underwent upper abdominal surgery were retrospectively divided according to the chosen postoperative analgesia: Group C, caudal ropivacaine-morphine; Group P, paravertebral catheter. We analyzed the following outcomes: requirement for additional analgesics, pain scores, need for mechanical ventilation and oxygen dosage, postoperative blood pressure and heart rate, time to pass first stool, time until first full meal, and complications. Twenty-one consecutive patients were included: 10 in Group C and 11 in Group P. Median age at surgery was 80 (47.5-270.0) and 84.5 (34.3-287.5) days, respectively. No difference was found between the two groups in requirement for additional analgesics at 24 h after surgery (median 1 in Group C vs 1 in Group P, P = 0.288, 95% CI: -2 to 1). BOPS pain scores were only lower in Group P when compared to Group C at 24 h after surgery (median 1 vs 2, P = 0.041, 95% CI: -2 to 0). None of the patients had perioperative complications. In this small series, there was no significant difference between caudal ropivacaine-morphine and paravertebral catheter for postoperative care in infants undergoing upper abdominal surgery. Further prospective studies are needed to compare the efficacy and incidence of complications of caudal block and paravertebral catheter for postoperative analgesia. © 2017 John Wiley & Sons Ltd.

Differential contributions of dorso-ventral and rostro-caudal prefrontal white matter tracts to cognitive control in healthy older adults.

Directory of Open Access Journals (Sweden)

Maren Strenziok

Full Text Available Prefrontal cortex mediates cognitive control by means of circuitry organized along dorso-ventral and rostro-caudal axes. Along the dorso-ventral axis, ventrolateral PFC controls semantic information, whereas dorsolateral PFC encodes task rules. Along the rostro-caudal axis, anterior prefrontal cortex encodes complex rules and relationships between stimuli, whereas posterior prefrontal cortex encodes simple relationships between stimuli and behavior. Evidence of these gradients of prefrontal cortex organization has been well documented in fMRI studies, but their functional correlates have not been examined with regard to integrity of underlying white matter tracts. We hypothesized that (a the integrity of specific white matter tracts is related to cognitive functioning in a manner consistent with the dorso-ventral and rostro-caudal organization of the prefrontal cortex, and (b this would be particularly evident in healthy older adults. We assessed three cognitive processes that recruit the prefrontal cortex and can distinguish white matter tracts along the dorso-ventral and rostro-caudal dimensions -episodic memory, working memory, and reasoning. Correlations between cognition and fractional anisotropy as well as fiber tractography revealed: (a Episodic memory was related to ventral prefrontal cortex-thalamo-hippocampal fiber integrity; (b Working memory was related to integrity of corpus callosum body fibers subserving dorsolateral prefrontal cortex; and (c Reasoning was related to integrity of corpus callosum body fibers subserving rostral and caudal dorsolateral prefrontal cortex. These findings confirm the ventrolateral prefrontal cortex's role in semantic control and the dorsolateral prefrontal cortex's role in rule-based processing, in accordance with the dorso-ventral prefrontal cortex gradient. Reasoning-related rostral and caudal superior frontal white matter may facilitate different levels of task rule complexity. This study is the

Differential contributions of dorso-ventral and rostro-caudal prefrontal white matter tracts to cognitive control in healthy older adults.

Science.gov (United States)

Strenziok, Maren; Greenwood, Pamela M; Santa Cruz, Sophia A; Thompson, James C; Parasuraman, Raja

2013-01-01

Prefrontal cortex mediates cognitive control by means of circuitry organized along dorso-ventral and rostro-caudal axes. Along the dorso-ventral axis, ventrolateral PFC controls semantic information, whereas dorsolateral PFC encodes task rules. Along the rostro-caudal axis, anterior prefrontal cortex encodes complex rules and relationships between stimuli, whereas posterior prefrontal cortex encodes simple relationships between stimuli and behavior. Evidence of these gradients of prefrontal cortex organization has been well documented in fMRI studies, but their functional correlates have not been examined with regard to integrity of underlying white matter tracts. We hypothesized that (a) the integrity of specific white matter tracts is related to cognitive functioning in a manner consistent with the dorso-ventral and rostro-caudal organization of the prefrontal cortex, and (b) this would be particularly evident in healthy older adults. We assessed three cognitive processes that recruit the prefrontal cortex and can distinguish white matter tracts along the dorso-ventral and rostro-caudal dimensions -episodic memory, working memory, and reasoning. Correlations between cognition and fractional anisotropy as well as fiber tractography revealed: (a) Episodic memory was related to ventral prefrontal cortex-thalamo-hippocampal fiber integrity; (b) Working memory was related to integrity of corpus callosum body fibers subserving dorsolateral prefrontal cortex; and (c) Reasoning was related to integrity of corpus callosum body fibers subserving rostral and caudal dorsolateral prefrontal cortex. These findings confirm the ventrolateral prefrontal cortex's role in semantic control and the dorsolateral prefrontal cortex's role in rule-based processing, in accordance with the dorso-ventral prefrontal cortex gradient. Reasoning-related rostral and caudal superior frontal white matter may facilitate different levels of task rule complexity. This study is the first to

Effect of caudal epidural steroid or saline injection in chronic lumbar radiculopathy: multicentre, blinded, randomised controlled trial

DEFF Research Database (Denmark)

Iversen, Trond; Solberg, Tore K; Romner, Bertil

2011-01-01

To assess the efficacy of caudal epidural steroid or saline injection in chronic lumbar radiculopathy in the short (6 weeks), intermediate (12 weeks), and long term (52 weeks).......To assess the efficacy of caudal epidural steroid or saline injection in chronic lumbar radiculopathy in the short (6 weeks), intermediate (12 weeks), and long term (52 weeks)....

Vitrification of caudal fin explants from zebrafish adult specimens.

Science.gov (United States)

Cardona-Costa, J; Roig, J; Perez-Camps, M; García-Ximénez, F

2006-01-01

No data on vitrification of tissue samples are available in fishes. Three vitrification solutions were compared: V1: 20% ethylene glycol and 20% dimethyl sulphoxide; V2: 25% propylene glycol and 20% dimethyl sulphoxide, and; V3: 20% propylene glycol and 13% methanol, all three prepared in Hanks' buffered salt solution plus 20 percent FBS, following the same one step vitrification procedure developed in mammals. Caudal fin tissue pieces were vitrified into 0.25 ml plastic straws in 30s and stored in liquid nitrogen for 3 days minimum, warmed (10s in nitrogen vapour and 5s in a 25 degree C water bath) and cultured (L-15 plus 20% FBS at 28.5 degree C). At the third day of culture, both attachment and outgrowing rates were recorded. V3 led to the worst results (8% of attachment rate). V1 and V2 allow higher attachment rates (V1: 63% vs V2: 50%. P < 0.05) but not significantly different outgrowing rates (83% to 94%). Vitrification of caudal fin pieces is advantageous in fish biodiversity conservation, particularly in the wild, due to the simplicity of procedure and equipment.

Caudal regression with sirenomelia and dysplasia renofacialis (Potter's syndrome)

Energy Technology Data Exchange (ETDEWEB)

Noeldge, G.; Billmann, P.; Boehm, N.

1982-05-01

A case of caudal regression in combination with sirenomelia and dysplasia renofacialis (Potter's syndrome) is reported. The formal pathogenesis of these malformations and clinical facts are shown and discussed. Findings of plain films, postmortal angiography and pathologic-anatomical changes are demonstrated.

Vadose zone studies at an industrial contaminated site: the vadose zone monitoring system and cross-hole geophysics

Science.gov (United States)

Fernandez de Vera, Natalia; Beaujean, Jean; Jamin, Pierre; Nguyen, Frédéric; Dahan, Ofer; Vanclooster, Marnik; Brouyère, Serge

2014-05-01

In order to improve risk characterization and remediation measures for soil and groundwater contamination, there is a need to improve in situ vadose zone characterization. However, most available technologies have been developed in the context of agricultural soils. Such methodologies are not applicable at industrial sites, where soils and contamination differ in origin and composition. In addition, most technologies are applicable only in the first meters of soils, leaving deeper vadose zones with lack of information, in particular on field scale heterogeneity. In order to overcome such difficulties, a vadose zone experiment has been setup at a former industrial site in Belgium. Industrial activities carried out on site left a legacy of soil and groundwater contamination in BTEX, PAH, cyanide and heavy metals. The experiment comprises the combination of two techniques: the Vadose Zone Monitoring System (VMS) and cross-hole geophysics. The VMS allows continuous measurements of water content and temperature at different depths of the vadose zone. In addition, it provides the possibility of pore water sampling at different depths. The system is formed by a flexible sleeve containing monitoring units along its depth which is installed in a slanted borehole. The flexible sleeve contains three types of monitoring units in the vadose zone: Time Domain Transmissometry (TDT), which allows water content measurements; Vadose Sampling Ports (VSP), used for collecting water samples coming from the matrix; the Fracture Samplers (FS), which are used for retrieving water samples from the fractures. Cross-hole geophysics techniques consist in the injection of an electrical current using electrodes installed in vertical boreholes. From measured potential differences, detailed spatial patterns about electrical properties of the subsurface can be inferred. Such spatial patterns are related with subsurface heterogeneities, water content and solute concentrations. Two VMS were

A Late Cretaceous theropod caudal vertebra from the Sultanate of Oman

NARCIS (Netherlands)

Schulp, Anne S.; Hanna, Samir S.; Hartman, Axel Frans; Jagt, John W M

2000-01-01

A caudal vertebra collected from conglomerates of the Al-Khod Formation (Late Cretaceous) in the Al-Khod area, Sultanate of Oman, is assigned to a medium-sized theropod dinosaur. The Al-Khod discovery represents one of the very few dinosaur records from the Middle East.

Régimen natural de caudales del río Ayuquila-Armería en el occidente de México

Directory of Open Access Journals (Sweden)

Demetrio Meza Rodríguez

2017-07-01

Full Text Available El caudal superficial a nivel cuenca, constituye hoy en día un proceso clave para los estudios hidrológicos de cualquier índole. El presente trabajo explora la reconstrucción del régimen natural de caudales de la cuenca del Río Ayuquila-Armería para el periodo 1963‑1991, su importancia radica en que el método usado, puede ser extrapolado a otras cuencas en México y Latinoamérica, donde se carece de datos hidrométricos puntuales. El campo de interés está centrado en la técnica de reconstrucción del caudal natural basándose en las precipitaciones y las temperaturas, en situaciones donde se carece de información hidrológica puntual, utilizando el modelo determinístico “precipitación-escurrimiento”. Es un modelo que requiere de pocos parámetros para su implementación, usando los procesos climáticos y físicos en el ámbito espacial y temporal, con la utilización del Sistemas de Información Geográfica (l. A partir de caudales calibrados en la misma área geográfica, es posible extrapolar el modelo de predicción a toda la cuenca. El resultado fue una base de datos de 29 años de régimen natural de caudales, con un caudal aproximado de 71.5 (m3 s-1, y con un volumen anual de 2254 (hm3 año-1, donde se observaron las pautas estacionales y su fluctuación a lo largo del año. El uso de esta metodología servirá de apoyo para la nueva norma NMX-AA-159-SCFI-2012, donde el principio científico para la determinación de caudal ecológico es el paradigma del régimen hidrológico natural.

Artérias mesentéricas cranial e caudal da paca (Cuniculus paca, L. 1766

Directory of Open Access Journals (Sweden)

Isabela Cristina de Souza Marques

2012-10-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2013v26n1p165 A paca (Cuniculus paca, Linnaeus, 1766 é um roedor de porte médio, que embora pertença à fauna brasileira, poucas são as informações sobre sua morfologia na literatura especializada. Nesse sentido, objetivou-se descrever a origem e as ramificações de suas artérias mesentéricas cranial e caudal no intuito de contribuir com estudos de anatomia comparativa. Foram utilizados dez animais, entre machos e fêmeas, que após o óbito, tiveram sua parede torácica rebatida entre a quarta e a sexta costelas, para a exposição da aorta torácica, a qual foi canulada no sentido caudal e procedeu-se a injeção de solução de neoprene do tipo látex, corado convenientemente, para o preenchimento de todo o sistema arterial. Estas preparações foram fixadas em solução aquosa de formol a 10% por período superior à 72h; em seguida, as peças foram dissecadas e as artérias mesentéricas cranial e caudal identificadas. A artéria mesentérica cranial se originava da aorta abdominal, caudalmente à artéria celíaca, emitindo os seguintes ramos arteriais: pancreaticoduodenal caudal, pancreáticos, jejunais, íleocólicos e cecais. A origem da artéria mesentérica caudal ocorria próximo ao final da aorta abdominal, e este vaso emitia a artéria cólica esquerda e a artéria retal cranial, da qual partiam as artérias sigmóideas. Constatou-se que houve pouca variação no padrão de ramificação das artérias em relação aos referidos roedores e mamíferos domésticos.

Slant Path Distances Through Cells in Cylindrical Geometry and an Application to the Computation of Isophotes

Energy Technology Data Exchange (ETDEWEB)

Rodney Whitaker

2007-12-17

In computer programs involving two-dimensional cylindrical geometry, it is often necessary to calculate the slant path distance in a given direction from a point to the boundary of a mesh cell. A subroutine, HOWFAR, has been written that accomplishes this, and is very economical in computer time. An example of its use is given in constructing the isophotes for a low altitude nuclear fireball.

Sirenomelia phenotype in bmp7;shh compound mutants: a novel experimental model for studies of caudal body malformations.

Science.gov (United States)

Garrido-Allepuz, Carlos; González-Lamuño, Domingo; Ros, Maria A

2012-01-01

Sirenomelia is a severe congenital malformation of the lower body characterized by the fusion of the legs into a single lower limb. This striking external phenotype consistently associates severe visceral abnormalities, most commonly of the kidneys, intestine, and genitalia that generally make the condition lethal. Although the causes of sirenomelia remain unknown, clinical studies have yielded two major hypotheses: i) a primary defect in the generation of caudal mesoderm, ii) a primary vascular defect that leaves the caudal part of the embryo hypoperfused. Interestingly, Sirenomelia has been shown to have a genetic basis in mice, and although it has been considered a sporadic condition in humans, recently some possible familial cases have been reported. Here, we report that the removal of one or both functional alleles of Shh from the Bmp7-null background leads to a sirenomelia phenotype that faithfully replicates the constellation of external and internal malformations, typical of the human condition. These mutants represent an invaluable model in which we have analyzed the pathogenesis of sirenomelia. We show that the signaling defect predominantly impacts the morphogenesis of the hindgut and the development of the caudal end of the dorsal aortas. The deficient formation of ventral midline structures, including the interlimb mesoderm caudal to the umbilicus, leads to the approximation and merging of the hindlimb fields. Our study provides new insights for the understanding of the mechanisms resulting in caudal body malformations, including sirenomelia.

Sirenomelia phenotype in bmp7;shh compound mutants: a novel experimental model for studies of caudal body malformations.

Directory of Open Access Journals (Sweden)

Carlos Garrido-Allepuz

Full Text Available Sirenomelia is a severe congenital malformation of the lower body characterized by the fusion of the legs into a single lower limb. This striking external phenotype consistently associates severe visceral abnormalities, most commonly of the kidneys, intestine, and genitalia that generally make the condition lethal. Although the causes of sirenomelia remain unknown, clinical studies have yielded two major hypotheses: i a primary defect in the generation of caudal mesoderm, ii a primary vascular defect that leaves the caudal part of the embryo hypoperfused. Interestingly, Sirenomelia has been shown to have a genetic basis in mice, and although it has been considered a sporadic condition in humans, recently some possible familial cases have been reported. Here, we report that the removal of one or both functional alleles of Shh from the Bmp7-null background leads to a sirenomelia phenotype that faithfully replicates the constellation of external and internal malformations, typical of the human condition. These mutants represent an invaluable model in which we have analyzed the pathogenesis of sirenomelia. We show that the signaling defect predominantly impacts the morphogenesis of the hindgut and the development of the caudal end of the dorsal aortas. The deficient formation of ventral midline structures, including the interlimb mesoderm caudal to the umbilicus, leads to the approximation and merging of the hindlimb fields. Our study provides new insights for the understanding of the mechanisms resulting in caudal body malformations, including sirenomelia.

Diagnosis and management of cranial and caudal nuchal bursitis in four horses.

Science.gov (United States)

García-López, José M; Jenei, Thomas; Chope, Kate; Bubeck, Kirstin A

2010-10-01

4 horses with a history of neck pain, abnormal head carriage, and related inability to perform were examined. Cranial nuchal bursitis was diagnosed in 2 horses, and caudal nuchal bursitis was diagnosed in the other 2. All 4 horses had prominent swelling in the region between the frontal bone and temporal fossa (ie, the poll) and abnormal head carriage. Ultrasonographic examination revealed fluid distention and synovial thickening of the cranial or caudal nuchal bursa in all 4 horses. Ultrasonography-guided aspiration of the affected region was performed successfully in 3 horses. Radiography revealed bony remodeling and mineralization over the dorsal aspect of the atlas in 1 horse and a radiolucency at the axis in another. Nuclear scintigraphy revealed an increase in radioisotope uptake at the level of C2 in 1 horse. Although a septic process was considered among the differential diagnoses in all horses, a septic process could only be confirmed in 1 horse. All horses were refractory to conservative management consisting of intrabursal injection of anti-inflammatory medications. Bursoscopic debridement and lavage of the affected bursae resulted in resolution of the clinical signs in all horses, and they all returned to their intended use. Cranial and caudal nuchal bursitis, of nonseptic or septic origin, should be considered as a differential diagnosis in horses with head and neck pain. Horses undergoing surgical intervention consisting of nuchal bursoscopy have the opportunity to return to their original degree of exercise.

Cryptorchidism as a caudal developmental field defect. A new description of cryptorchidism associated with malformations and dysplasias of the kidneys, the ureters and the spine from T10 to S5

DEFF Research Database (Denmark)

Cortes, D; Thorup, J M; Beck, B L

1998-01-01

individuals with tritonmelia, the male variant of sirenomelia. Sirenomelia/tritonmelia is an extreme degree of abnormal differentiation of the caudal developmental field, also called caudal dysplasia, the caudal regression syndrome and the caudal regression malformation sequence. Caudal developmental field...

Postoperative analgesia in children when using clonidine in addition to fentanyl with bupivacaine given caudally.

Science.gov (United States)

Jarraya, Anouar; Elleuch, Sahar; Zouari, Jawhar; Smaoui, Mohamed; Laabidi, Sofiene; Kolsi, Kamel

2016-01-01

The aim of the study was to evaluate the efficacy of clonidine in association with fentanyl as an additive to bupivacaine 0.25% given via single shot caudal epidural in pediatric patients for postoperative pain relief. In the present prospective randomized double blind study, 40 children of ASA-I-II aged 1-5 years scheduled for infraumblical surgical procedures were randomly allocated to two groups to receive either bupivacaine 0.25% (1 ml/kg) with fentanyl 1 μg/kg and clonidine 1μg/kg (group I) or bupivacaine 0.25% (1 ml/kg) with fentanyl 1 μg/kg (group II). Caudal block was performed after the induction of general anesthesia. Postoperatively patients were observed for analgesia, sedation, hemodynamic parameters, and side effects or complications. Both the groups were similar with respect to patient and various block characteristics. Heart rate and blood pressure were not different in 2 groups. Significantly prolonged duration of post-operative analgesia was observed in group I (Pbupivacaine in single shot caudal epidural in children may provide better and longer analgesia after infraumblical surgical procedures.

Sistematização da origem, da distribuição e dos territórios da artéria cerebral caudal na superfície do encéfalo em gatos Systematization of the origin, distribution and territory of the caudal cerebral artery on the surface of the encephalon in cats

Directory of Open Access Journals (Sweden)

Eduardo Maurício Mendes de Lima

2010-09-01

Full Text Available Foram estudados 26 encéfalos de gatos, adultos, sem diferenciação de sexo, sem raça definida, corados com látex e fixados por solução aquosa de formaldeído. As artérias cerebrais caudais, direita e esquerda, apresentaram-se únicas em 96,1 e 88,4% dos casos, respectivamente. Em 69,2% dos casos no antímero direito e 80,8% no esquerdo, a artéria cerebral caudal originou-se pela anastomose entre o ramo caudal da artéria carótida interna, com maior contribuição, e o ramo terminal da artéria basilar. Em 88,4% dos casos no antímero direito e em 84,6% no esquerdo, a artéria cerebral caudal originou a artéria tectal rostral e um ramo caudal. O ramo caudal bifurcou-se e vascularizou os colículos rostrais e caudais dos corpos quadrigêmeos e em alguns casos contribuiu na formação do plexo coroide do terceiro ventrículo. A artéria tectal rostral seguiu ventralmente ao lobo piriforme e durante seu trajeto liberou ramos para o hipocampo e, no antímero esquerdo, supriu a superfície dorsal do tálamo, contribuindo para a formação do plexo coroide do terceiro ventrículo.In this study were used 26 brains of adult cats, without sex differentiation and definable race, colored with latex and fixed in formaldehyde aqueous solution. The right and left caudal cerebral arteries were single in 96.1% and 88.4% of the sample, respectively. In 69.2% of the samples on the right side and 80.8% on the left, the caudal cerebral artery fin from the anastomosis behind the caudal branch of the internal carotid artery, with a large contribution, and the basal artery terminal branch. In 88.4% of the samples on the right side and 84.6% on the left, the caudal cerebral artery showed the tectal rostral artery and one caudal branche. The caudal branch forked in two branches that supplied the rostral and caudal colliculis of the quadruplet bodies and formed the choroid plexus of the third ventricle. The tectal rostral artery followed ventrally to the

Ecomorphological inferences in early vertebrates: reconstructing Dunkleosteus terrelli (Arthrodira, Placodermi) caudal fin from palaeoecological data.

Science.gov (United States)

Ferrón, Humberto G; Martínez-Pérez, Carlos; Botella, Héctor

2017-01-01

Our knowledge about the body morphology of many extinct early vertebrates is very limited, especially in regard to their post-thoracic region. The prompt disarticulation of the dermo-skeletal elements due to taphonomic processes and the lack of a well-ossified endoskeleton in a large number of groups hinder the preservation of complete specimens. Previous reconstructions of most early vertebrates known from partial remains have been wholly based on phylogenetically closely related taxa. However, body design of fishes is determined, to a large extent, by their swimming mode and feeding niche, making it possible to recognise different morphological traits that have evolved several times in non-closely related groups with similar lifestyles. Based on this well-known ecomorphological correlation, here we propose a useful comparative framework established on extant taxa for predicting some anatomical aspects in extinct aquatic vertebrates from palaeoecological data and vice versa. For this, we have assessed the relationship between the locomotory patterns and the morphological variability of the caudal region in extant sharks by means of geometric morphometrics and allometric regression analysis. Multivariate analyses reveal a strong morphological convergence in non-closely related shark species that share similar modes of life, enabling the characterization of the caudal fin morphology of different ecological subgroups. In addition, interspecific positive allometry, affecting mainly the caudal fin span, has been detected. This phenomenon seems to be stronger in sharks with more pelagic habits, supporting its role as a compensation mechanism for the loss of hydrodynamic lift associated with the increase in body size, as previously suggested for many other living and extinct aquatic vertebrates. The quantification of shape change per unit size in each ecological subgroup has allowed us to establish a basis for inferring not only qualitative aspects of the caudal fin

Ecomorphological inferences in early vertebrates: reconstructing Dunkleosteus terrelli (Arthrodira, Placodermi caudal fin from palaeoecological data

Directory of Open Access Journals (Sweden)

Humberto G. Ferrón

2017-12-01

Full Text Available Our knowledge about the body morphology of many extinct early vertebrates is very limited, especially in regard to their post-thoracic region. The prompt disarticulation of the dermo-skeletal elements due to taphonomic processes and the lack of a well-ossified endoskeleton in a large number of groups hinder the preservation of complete specimens. Previous reconstructions of most early vertebrates known from partial remains have been wholly based on phylogenetically closely related taxa. However, body design of fishes is determined, to a large extent, by their swimming mode and feeding niche, making it possible to recognise different morphological traits that have evolved several times in non-closely related groups with similar lifestyles. Based on this well-known ecomorphological correlation, here we propose a useful comparative framework established on extant taxa for predicting some anatomical aspects in extinct aquatic vertebrates from palaeoecological data and vice versa. For this, we have assessed the relationship between the locomotory patterns and the morphological variability of the caudal region in extant sharks by means of geometric morphometrics and allometric regression analysis. Multivariate analyses reveal a strong morphological convergence in non-closely related shark species that share similar modes of life, enabling the characterization of the caudal fin morphology of different ecological subgroups. In addition, interspecific positive allometry, affecting mainly the caudal fin span, has been detected. This phenomenon seems to be stronger in sharks with more pelagic habits, supporting its role as a compensation mechanism for the loss of hydrodynamic lift associated with the increase in body size, as previously suggested for many other living and extinct aquatic vertebrates. The quantification of shape change per unit size in each ecological subgroup has allowed us to establish a basis for inferring not only qualitative aspects of

Comparison of collagen fibre architecture between slow-twitch cranial and fast-twitch caudal parts of broiler M. latissimus dorsi.

Science.gov (United States)

Nakamura, Y N; Iwamoto, H; Tabata, S; Ono, Y

2003-07-01

1. Collagen fibre architectures of perimysium and endomysium in the slow-twitch cranial and fast-twitch caudal parts of broiler M. latissimus dorsi were compared. 2. Type I and III collagens were distributed in both perimysium and endomysium as indicated by their positive immunohistochemical reactions to polyclonal antibodies. 3. Cells invested by endomysium with no myofibres were larger in the cranial part because of the presence of larger slow-twitch myofibres. The honeycomb structure of endomysium was divided into several parts by thick perimysium. 4. The thick perimysial collagen fibres with parallel fibrils, which were interconnected by the loose reticular fibrils and thin fibres, were more numerous and thicker in the cranial part than the caudal. 5. Thick endomysial sidewall of cells in the cranial part was composed of a rougher reticulum of slightly thicker collagen fibrils compared with the thin sidewall in the caudal part. 6. These results indicated that both perimysial constitutions of collagen fibres and endomysial collagen fibrils had attained much larger growth in the slow-twitch cranial part than the fast-twitch caudal in broiler latissimus dorsi muscle.

Destruction of the medial forebrain bundle caudal to the site of stimulation reduces rewarding efficacy but destruction rostrally does not.

Science.gov (United States)

Gallistel, C R; Leon, M; Lim, B T; Sim, J C; Waraczynski, M

1996-08-01

Rats with an electrode in the medial forebrain bundle (MFB) in or near the ventral tegmental area and another at the level of the rostral hypothalamus sustained large electrolytic lesions at either the rostral or the caudal electrode. The rewarding efficacy of stimulation through the other electrode was determined before and after the lesion. Massive damage to the MFB in the rostral lateral hypothalamus (LH) generally had little effect on the rewarding efficacy of more caudal stimulation, whereas large lesions in the caudal MFB generally reduced the rewarding efficacy of LH stimulation by 35-60%. Similar reductions were produced by knife cuts in the caudal MFB. These results appear to be inconsistent with the hypothesis that the reward fibers consist either of descending or ascending fibers coursing in or near the MFB. It is suggested that the reward fibers are collaterals from neurons with both their somata and their behaviorally significant terminals located primarily in the midbrain.

Orexin inputs to caudal raphé neurons involved in thermal, cardiovascular, and gastrointestinal regulation.

Science.gov (United States)

Berthoud, Hans-Rudolf; Patterson, Laurel M; Sutton, Gregory M; Morrison, Christopher; Zheng, Huiyuan

2005-02-01

Orexin-expressing neurons in the lateral hypothalamus with their wide projections throughout the brain are important for the regulation of sleep and wakefulness, ingestive behavior, and the coordination of these behaviors in the environmental context. To further identify downstream effector targets of the orexin system, we examined in detail orexin-A innervation of the caudal raphe nuclei in the medulla, known to harbor sympathetic preganglionic motor neurons involved in thermal, cardiovascular, and gastrointestinal regulation. All three components of the caudal raphe nuclei, raphe pallidus, raphe obscurus, and parapyramidal nucleus, are innervated by orexin-A-immunoreactive fibers. Using confocal microscopy, we demonstrate close anatomical appositions between varicose orexin-A immunoreactive axon profiles and sympathetic premotor neurons identified with either a transneuronal retrograde pseudorabies virus tracer injected into the interscapular brown fat pads, or with in situ hybridization of pro-TRH mRNA. Furthermore, orexin-A injected into the fourth ventricle induced c-Fos expression in the raphe pallidus and parapyramidal nucleus. These findings suggest that orexin neurons in the hypothalamus can modulate brown fat thermogenesis, cardiovascular, and gastrointestinal functions by acting directly on neurons in the caudal raphe nuclei, and support the idea that orexin's simultaneous stimulation of food intake and sympathetic activity might have evolved as a mechanism to stay alert while foraging.

Fluoroscopically guided caudal epidural steroid injection for management of degenerative lumbar spinal stenosis: short-term and long-term results

Energy Technology Data Exchange (ETDEWEB)

Lee, Joon Woo; Myung, Jae Sung; Kang, Heung Sik [Seoul National University Bundang Hospital, Department of Radiology, Seong Nam, Gyeongi-do (Korea); Park, Kun Woo; Yeom, Jin S. [Seoul National University Bundang Hospital, Department of Orthopaedic Surgery, Seong Nam, Gyeongi-do (Korea); Kim, Ki-Jeong; Kim, Hyun-Jib [Seoul National University Bundang Hospital, Department of Neurosurgery, Seong Nam, Gyeongi-do (Korea)

2010-07-15

To evaluate the short-term and long-term effects of fluoroscopically guided caudal epidural steroid injection (ESI) for the management of degenerative lumbar spinal stenosis (DLSS) and to analyze outcome predictors. All patients who underwent caudal ESI in 2006 for DLSS were included in the study. Response was based on chart documentation (aggravated, no change, slightly improved, much improved, no pain). In June 2009 telephone interviews were conducted, using formatted questions including the North American Spine Society (NASS) patient satisfaction scale. For short-term and long-term effects, age difference was evaluated by the Mann-Whitney U test, and gender, duration of symptoms, level of DLSS, spondylolisthesis, and previous operations were evaluated by Fisher's exact test. Two hundred and sixteen patients (male: female = 75:141; mean age 69.2 years; range 48{proportional_to}91 years) were included in the study. Improvements (slightly improved, much improved, no pain) were seen in 185 patients (85.6%) after an initial caudal ESI and in 189 patients (87.5%) after a series of caudal ESIs. Half of the patients (89/179, 49.8%) replied positively to the NASS patient satisfaction scale (1 or 2). There were no significant outcome predictors for either the short-term or the long-term responses. Fluoroscopically guided caudal ESI was effective for the management of DLSS (especially central canal stenosis) with excellent short-term and good long-term results, without significant outcome predictors. (orig.)

[Magnetic resonance imaging features of a caudal cruciate ligament rupture associated with a suspected bone bruise lesion in a dog].

Science.gov (United States)

Schmohl, M; Konar, M; Tassani-Prell, M; Rupp, S

2014-04-16

In this case study we describe a surgically confirmed caudal cruciate ligament rupture in a 10-year-old Border Collie. Magnetic resonance imaging (MRI) demonstrated a complete rupture of the caudal cruciate ligament, a suspected bone bruise lesion on the proximolateral tibia and a muscle strain injury of the M. flexor digitorum lateralis. In human medicine, bone bruise lesions in MRI have been described as "footprint injuries" and can thereby explain the mechanism of trauma in ligament injuries. The combination of the MRI findings in this case can help to understand how the rarely diagnosed isolated rupture of the caudal cruciate ligament occurred in this dog.

Black Hole Growth Is Mainly Linked to Host-galaxy Stellar Mass Rather Than Star Formation Rate

Science.gov (United States)

Yang, G.; Chen, C.-T. J.; Vito, F.; Brandt, W. N.; Alexander, D. M.; Luo, B.; Sun, M. Y.; Xue, Y. Q.; Bauer, F. E.; Koekemoer, A. M.; Lehmer, B. D.; Liu, T.; Schneider, D. P.; Shemmer, O.; Trump, J. R.; Vignali, C.; Wang, J.-X.

2017-06-01

We investigate the dependence of black hole accretion rate (BHAR) on host-galaxy star formation rate (SFR) and stellar mass (M *) in the CANDELS/GOODS-South field in the redshift range of 0.5≤slant zteam through spectral energy distribution fitting. The average BHAR is correlated positively with both SFR and M *, and the BHAR-SFR and BHAR-M * relations can both be described acceptably by linear models with a slope of unity. However, BHAR appears to be correlated more strongly with M * than SFR. This result indicates that M * is the primary host-galaxy property related to supermassive black hole (SMBH) growth, and the apparent BHAR-SFR relation is largely a secondary effect due to the star-forming main sequence. Among our sources, massive galaxies ({M}* ≳ {10}10{M}⊙ ) have significantly higher BHAR/SFR ratios than less massive galaxies, indicating that the former have higher SMBH fueling efficiency and/or higher SMBH occupation fraction than the latter. Our results can naturally explain the observed proportionality between {M}{BH} and M * for local giant ellipticals and suggest that their {M}{BH}/{M}* is higher than that of local star-forming galaxies. Among local star-forming galaxies, massive systems might have higher {M}{BH}/{M}* compared to dwarfs.

White holes and eternal black holes

International Nuclear Information System (INIS)

Hsu, Stephen D H

2012-01-01

We investigate isolated white holes surrounded by vacuum, which correspond to the time reversal of eternal black holes that do not evaporate. We show that isolated white holes produce quasi-thermal Hawking radiation. The time reversal of this radiation, incident on a black hole precursor, constitutes a special preparation that will cause the black hole to become eternal. (paper)

Caudal venous return through a left azygos vein in a dog

International Nuclear Information System (INIS)

Sammarco, C.D.; Regan, J.; Ward, C.R.; Buchanan, J.D.

1995-01-01

The Clinical, radiologic and echocardiographic findings in a one-year old dog with mild subvalvular aortic stenosis and aberrant caudal vena circulation are described. Aberrant systemic venous return to the right side of the heart usually has little clinical significance, but the unusual features in survey radiographs, contrast angiograms and contrast echocardiograms constitute the reasons for this report

Natural gas product and strategic analysis

Energy Technology Data Exchange (ETDEWEB)

Layne, A.W.; Duda, J.R.; Zammerilli, A.M.

1993-12-31

Product and strategic analysis at the Department of Energy (DOE)/Morgantown Energy Technology Center (METC) crosscuts all sectors of the natural gas industry. This includes the supply, transportation, and end-use sectors of the natural-gas market. Projects in the Natural Gas Resource and Extraction supply program have been integrated into a new product focus. Product development facilitates commercialization and technology transfer through DOE/industry cost-shared research, development, and demonstration (RD&D). Four products under the Resource and Extraction program include Resource and Reserves; Low Permeability Formations; Drilling, Completion, and Stimulation: and Natural Gas Upgrading. Engineering process analyses have been performed for the Slant Hole Completion Test project. These analyses focused on evaluation of horizontal-well recovery potential and applications of slant-hole technology. Figures 2 and 3 depict slant-well in situ stress conditions and hydraulic fracture configurations. Figure 4 presents Paludal Formation coal-gas production curves used to optimize the hydraulic fracture design for the slant well. Economic analyses have utilized data generated from vertical test wells to evaluate the profitability of horizontal technology for low-permeability formations in Yuma County, Colorado, and Maverick County, Texas.

Caudal fin allometry in the white shark Carcharodon carcharias: implications for locomotory performance and ecology

Science.gov (United States)

Lingham-Soliar, Theagarten

2005-05-01

Allometric scaling analysis was employed to investigate the consequences of size evolution on hydrodynamic performance and ecology in the white shark Carcharodon carcharias. Discriminant analysis using the power equation y=axb was negative for caudal fin span (S) versus fork length (FL) in C. carcharias. In contrast in two delphinid species, Delphinus capensis and Tursiops aduncus, the span of the flukes versus fork length rises in positive allometric fashion, and strong positive allometry of S versus √A (area) was also recorded. The latter reflects a high lift/drag ratio. S versus √A in C. carcharias displays negative allometry and consequently a lower lift/drag ratio. A lower aspect ratio (AR) caudal fin in C. carcharias compared to that of the delphinids (mean 3.33 and 4.1, respectively) and other thunniform swimmers provides the potential for better maneuverability and acceleration. The liver in sharks is frequently associated with a buoyancy function and was found to be positively allometric in C. carcharias. The overall findings suggest that the negatively allometric caudal fin morphometrics in C. carcharias are unlikely to have deleterious evolutionary fitness consequences for predation. On the contrary, when considered in the context of positive liver allometry in C. carcharias it is hereby suggested that buoyancy may play a dominant role in larger white sharks in permitting slow swimming while minimizing energy demands needed to prevent sinking. In contrast hydrodynamic lift is considered more important in smaller white sharks. Larger caudal fin spans and higher lift/drag ratio in smaller C. carcharias indicate greater potential for prolonged, intermediate swimming speeds and for feeding predominantly on fast-moving fish, in contrast to slow-swimming search patterns of larger individuals for predominantly large mammalian prey. Such data may provide some answers to the lifestyle and widespread habitat capabilities of this still largely mysterious animal.

Comparison of preemptive intravenous paracetamol and caudal block in terms of analgesic and hemodynamic parameters in children

Directory of Open Access Journals (Sweden)

Serbülent Gökhan Beyaz

2012-06-01

Full Text Available Objectives: Paracetamol has a widespread use for feverand symptomatic relief of pain in children. The aim ofthis study was to compare analgesic effects of preemptiveintravenous (i.v. paracetamol, and caudal block withlevobupivacaine.Materials and methods: A total of 60 children with ASAI-II physical status, aged 5-15 years and undergoing inguinalhernia repair, were randomly allocated to threegroups so that each group contained 20 patients. Group Pchildren received i.v. 15mg/kg paracetamol. Group C receivedonly caudal block with levobupivacaine, and GroupPC received both i.v. paracetamol, and caudal block withlevobupivacaine. Pain level assessed by modified EasternOntario Children’s Hospital pain scale (mCHEOPs,sedation status by Ramsey sedation scale at postoperative5, 15, 30 min and 1,3, and 6th hours.Results: No significant differences were found in age,gender distribution, body weight, ASA status, type andduration of surgery between three groups (p>0.05. Althoughsignificant difference were found in mCHEOPsscores within groups by repeated measures, no differenceof pain scores was observed between three groups(p>0.05. There were no significant differences in the hemodynamicparameters (heart rate, blood pressure bothwithin groups and between groups (p>0.05.Conclusions: Preemptive intravenous paracetamol hadsimilar analgesic effects compared with caudal block withlevobupivacaine with regard to postoperative pain scoresin children undergoing inguinal hernia repair. No hemodynamicor other adverse effects were observed withintravenous paracetamol. J Clin Exp Invest 2012; 3(2:202-208

Conjoined legs: Sirenomelia or caudal regression syndrome?

Directory of Open Access Journals (Sweden)

Sakti Prasad Das

2013-01-01

Full Text Available Presence of single umbilical persistent vitelline artery distinguishes sirenomelia from caudal regression syndrome. We report a case of a12-year-old boy who had bilateral umbilical arteries presented with fusion of both legs in the lower one third of leg. Both feet were rudimentary. The right foot had a valgus rocker-bottom deformity. All toes were present but rudimentary. The left foot showed absence of all toes. Physical examination showed left tibia vara. The chest evaluation in sitting revealed pigeon chest and elevated right shoulder. Posterior examination of the trunk showed thoracic scoliosis with convexity to right. The patient was operated and at 1 year followup the boy had two separate legs with a good aesthetic and functional results.

Conjoined legs: Sirenomelia or caudal regression syndrome?

Science.gov (United States)

Das, Sakti Prasad; Ojha, Niranjan; Ganesh, G Shankar; Mohanty, Ram Narayan

2013-07-01

Presence of single umbilical persistent vitelline artery distinguishes sirenomelia from caudal regression syndrome. We report a case of a12-year-old boy who had bilateral umbilical arteries presented with fusion of both legs in the lower one third of leg. Both feet were rudimentary. The right foot had a valgus rocker-bottom deformity. All toes were present but rudimentary. The left foot showed absence of all toes. Physical examination showed left tibia vara. The chest evaluation in sitting revealed pigeon chest and elevated right shoulder. Posterior examination of the trunk showed thoracic scoliosis with convexity to right. The patient was operated and at 1 year followup the boy had two separate legs with a good aesthetic and functional results.

Anomalous refraction of light through slanted-nanoaperture arrays on metal surface

International Nuclear Information System (INIS)

Kim, Myungji; Jung, Yun Suk; Xi, Yonggang; Kim, Hong Koo

2015-01-01

We report a nanoapertured metal surface that demonstrates anomalous refraction of light for a wide range of incident angles. A nanoslit aperture is designed to serve as a tilted vertical-dipole whose radiation pattern orients to a glancing angle direction to substrate. An array of such slanted nanoslits formed in a metal film redirects an incident beam into the direction of negative refraction angle: the aperture-transmitted wave makes a far-field propagation to the tilt-oriented direction of radiation pattern. The thus-designed nanoaperture array demonstrates the −1st order diffraction (i.e., to the negative refraction-angle direction) with well-suppressed background transmission (the zero-order direct transmission and other higher-order diffractions). Engineering the radiation pattern of nanoaperture offers an approach to overcoming the limits of conventional diffractive/refractive optics and complementing metasurface-based nano-optics

CARACTERÍSTICAS DE LA CIRCULACIÓN TROPOSFÉRICA ASOCIADA A LAS VARIACIONES INTERANUALES DEL CAUDAL DEL RÍO TECKA – GUALJAINA, ARGENTINA

Directory of Open Access Journals (Sweden)

Mariana P. Torrero

2016-06-01

Full Text Available La cuenca del río Tecka – Gualjaina se localiza al Noroeste de la provincia de Chubut, Argentina y desarrolla una superficie de 5.318 km2. El trabajo explora los forzantes del sistema atmósfera-océano asociados a la variabilidad interanual del caudal para la temporada de máximo caudal (de junio a noviembre, que representa el 80% del total anual, y de mínimo caudal (de diciembre a mayo. El balance hídrico de la cuenca arrojó condiciones de aridez, por lo que el comportamiento temporal del caudal depende del de la precipitación. En el registro disponible 1956-2013 la serie de máximo caudal presentó tendencia negativa, con un cambio de régimen en las anomalías de caudal a comienzos de los 80, pasando de un predominio positivo antes a otro negativo después. La serie de mínimo caudal mostró ser más estacionaria, sin tendencia significativa. Los ciclos dominantes en ambas series temporales sólo se observaron en la alta frecuencia interanual ( 2 años y 4-5 años. Las teleconexiones y forzantes asociados a las series de caudal se analizaron para el período 1979-2013 mediante el reanálisis del ERA-Interim. Las variaciones interanuales del caudal máximo estuvieron asociadas a teleconexión troposférica de baja frecuencia (interanual simétrica respecto del Ecuador, posiblemente asociada a variaciones en la convección tropical entre aproximadamente 10oN-10oS y 150oE-180oE, inducidas por variaciones de temperatura superficial del mar en el Pacífico occidental ecuatorial (entre 180oO-150oO. La teleconexión afectó la posición e intensidad de las corrientes en chorro subtropical y polar, alterando la trayectoria de sistemas baroclínicos invernales que precipitan en la región. Las variaciones interanuales del mínimo caudal estuvieron asociadas a una variabilidad de altas latitudes simétricamente anular, modulada por un tren de onda 3 en latitudes medias sobre el Pacífico Sur y el Atlántico Sur. Estas características pudieron

The anatomy and histology of caudal autotomy and regeneration in lizards.

Science.gov (United States)

Gilbert, Emily A B; Payne, Samantha L; Vickaryous, Matthew K

2013-01-01

Abstract Caudal autotomy-the ability to self-detach the tail-is a dramatic adaptation common to many structural-grade lizards. For most species, tail loss is followed by the equally dramatic phenomenon of tail regeneration. Here we review the anatomy and histology of caudal autotomy and regeneration in lizards, drawing heavily from research published over the past 2 decades. The autotomous tail is characterized by various structural adaptations, which act to minimize blood loss and trauma to adjacent tissues. The early phase of wound healing involves a leukocytic response but limited inflammation. Reepithelialization via a specialized wound epithelium is not only critical for scar-free healing but also necessary for subsequent tissue patterning and regenerative outgrowth. Regeneration begins with the formation of the blastema, a mass of proliferating mesenchymal-like cells. As the blastema expands, it is invaded by blood vessels and the spinal cord. Whereas the replacement tail outwardly resembles the original appendage, it differs in several notable respects, including the tissue composition and organization of the skeleton, muscular system, and spinal cord. Increasingly, the lizard tail is being recognized among biomedical scientists as an important model for the study of wound healing and multitissue restoration.

Three-dimensional motion pattern of the caudal lumbar and lumbosacral portions of the vertebral column of dogs.

Science.gov (United States)

Benninger, Monika I; Seiler, Gabriela S; Robinson, Leanne E; Ferguson, Stephen J; Bonél, Harald M; Busato, André R; Lang, Johann

2004-05-01

To evaluate the 3-dimensional motion pattern including main and coupled motions of the caudal lumbar and lumbosacral portions of the vertebral column of dogs. Vertebral columns of 9 German Shepherd Dogs (GSDs) and 16 dogs of other breeds with similar body weights and body conditions. Main and coupled motions of the caudal lumbar and lumbosacral portions of the vertebral column (L4 to S1) were determined by use of a testing apparatus that permitted precise application of known pure moments to the vertebral column. Motion was compared between GSDs and dogs of other breeds. All specimens had a similar motion pattern consisting of main motion and a certain amount of coupled motion including translation. Vertebral columns of GSDs had significantly less main motion in all directions than that of dogs of other breeds. Translation was similar in GSDs and dogs of other breeds and was smallest at the lumbosacral motion segment. Results indicated that motion in the caudal lumbar and lumbosacral portions of the vertebral column of dogs is complex and provided a basis for further studies evaluating abnormal vertebral columns.

Modified Labial Button Technique for Maintaining Occlusion After Caudal Mandibular Fracture/Temporomandibular Joint Luxation in the Cat.

Science.gov (United States)

Goodman, Alice E; Carmichael, Daniel T

2016-03-01

Maxillofacial trauma in cats often results in mandibular symphyseal separation in addition to injuries of the caudal mandible and/or temporomandibular joint (TMJ). Caudal mandibular and TMJ injuries are difficult to access and stabilize using direct fixation techniques, thus indirect fixation is commonly employed. The immediate goals of fixation include stabilization for return to normal occlusion and function with the long-term objective of bony union. Indirect fixation techniques commonly used for stabilization of caudal mandibular and temporomandibular joint fracture/luxation include maxillomandibular fixation (MMF) with acrylic composite, interarcade wiring, tape muzzles, and the bignathic encircling and retaining device (BEARD) technique. This article introduces a modification of the previously described "labial reverse suture through buttons" technique used by Koestlin et al and the "labial locking with buttons" technique by Rocha et al. In cases with minimally displaced subcondylar and pericondylar fractures without joint involvement, the labial button technique can provide sufficient stabilization for healing. Advantages of the modified labial button technique include ease of application, noninvasive nature, and use of readily available materials. The construct can remain in place for a variable of amount of time, depending on its intended purpose. It serves as an alternative to the tape muzzle, which is rarely tolerated by cats. This technique can be easily used in conjunction with other maxillomandibular repairs, such as cerclage wire fixation of mandibular symphyseal separation. The purpose of this article is to demonstrate a modified labial button technique for maintaining occlusion of feline caudal mandibular fractures/TMJ luxations in a step-by-step fashion.

Development of the caudal exoskeleton of the pliomerid trilobite Hintzeia plicamarginis new species

Science.gov (United States)

Simpson, A.G.; Hughes, N.C.; Kopaska-Merkel, D. C.; Ludvigsen, R.

2005-01-01

The later juvenile ontogeny of the caudal plate of the early Ordovician pliomerid trilobite Hintzeia plicamarginis new species likely comprised an initial phase during which the rate of appearance of new segments subterminally exceeded that of segment release into the thorax, a short phase of constant segment numbers, and a later phase during which release occurred but in which no new segments appeared. A distinct terminal region became manifest in the second phase. During the second and third phases growth coefficients for individual segments were about 1.1-1.2 per instar. Although the shapes of segments varied during growth, the pattern of ontogenetic shape change appears to have been broadly similar among segments. This suggests an homonomous trunk segment morphology regardless of thoracic or caudal identity in maturity. These results imply that control of trunk exoskeletal segment appearance and articulation were decoupled in this trilobite, and that the terminal region had a distinct mature morphology. H. plicamarginis is described as a new species. ?? Blackwell Publishing, Inc.

Single dose caudal tramadol with bupivacaine and bupivacaine alone in pediatric inguinoscrotal surgeries

International Nuclear Information System (INIS)

Khalid, A.; Siddiqui, S.Z.; Aftab, S.

2007-01-01

To determine the postoperative analgesic effect of Tramadol when given with caudally administered Bupivacaine in children undergoing inguinoscrotal surgeries. A total of 60 children, undergoing inguinoscrotal surgeries, aged from 1 to 12 years, ASA 1 and 2, were included. The patients were divided into two equal groups. The group given Bupivacaine with Tramadol was called group BT and the group which was given only Bupivacaine was labeled as group B. Group BT was given 0.25%, 0.8 ml/kg Bupivacaine and Tramadol 2 mg/kg while the other group B was given 0.25%, 0.8 ml/kg Bupivacaine through caudal route after induction of general anesthesia. No other analgesic was given intraoperatively. The postoperative pain was evaluated by using visual analogue scale/Ocher face scale/CHEOPS and sedation was assessed by 5 points sedation score at immediate postoperative period 1,2,3,4,6,12 and 24 hours. Supplemental analgesia in the form of paracetamol suppositories and syrup ibuprofen was given accordingly. SaO 2, pulse, blood pressure, and motor block were monitored in all the patients. Addition of Tramadol with Bupivacaine resulted in meaningfully increased postoperative analgesic period (16.06 +- 4.04 hours). No other side effects like respiratory depression, pruritus, urinary retention were found in both the groups except for nausea and vomiting. The demand for supplemental analgesia was more in the patients belonging to B group than BT group. The sedation scores were similar in both the groups. The use of Tramadol as an additive with local anesthetics can prolong the postoperative analgesic period when administered caudally. Its use is safe in children. (author)

Slanted annular aperture arrays as enhanced-transmission metamaterials: Excitation of the plasmonic transverse electromagnetic guided mode

Energy Technology Data Exchange (ETDEWEB)

Ndao, Abdoulaye; Salut, Roland; Baida, Fadi I., E-mail: fbaida@univ-fcomte.fr [Département d' Optique P.M. Duffieux, Institut FEMTO-ST, UMR 6174 CNRS, Université de Franche–Comté, 25030 Besançon Cedex (France); Belkhir, Abderrahmane [Laboratoire de Physique et Chimie Quantique, Université Mouloud Mammeri, Tizi-Ouzou (Algeria)

2013-11-18

We present here the fabrication and the optical characterization of slanted annular aperture arrays engraved into silver film. An experimental enhanced transmission based on the excitation of the cutoff-less plasmonic guided mode of the nano-waveguides (the transmission electron microscopy mode) is demonstrated and agrees well with the theoretical predicted results. By the way, even if it is less efficient (70% → 20%), an enhanced transmission can occur at larger wavelength value (720 nm–930 nm) compared to conventional annular aperture arrays structure by correctly setting the metal thickness.

Comparison of the effect of sevoflurane and halothane anesthesia on the fall in hear rate as a predictor of successful single shot caudal epidural in children

International Nuclear Information System (INIS)

Mercan, A.; Ture, H.; Sayin, Murat M.; Koner, O.; Aykac, B.; Sozubir, S.

2009-01-01

Objective was to investigate the effect of sevoflurane anesthesia on heart rate (HR) fall with the injection of the initial drug in caudal space to confirm the correct needle placement. After the ethical approval was obtained from the hospital's ethics committee, a prospective randomized, clinical study was designed in Yeditepe University Hospital, in 2007. Children aged 1-12 years, scheduled for infraumblical surgery under general anesthesia and caudal block were included in the study. Anesthesia was induced and maintained by sevoflurane in group S (n=8) and by halothane in group H (n=82). Baseline HR was recorded before the caudal block was performed. The HR changes during the initial dose and total drug injection was recorded followed by 2 more HR recordings taken 5 and 10 minutes after caudal injection. The success of the block was recorded by a blind observer. There were 167 children included in the study. Caudal block success was 96.5% in group S and 97.6% in group H. Basal HR was 110.9+-10.9 in group S and 105.9+-10.1 in group H. Following the initial drug injection, mean HR was 109.8+-10.9 in group S and 102.9+-9.9 in group H. It was significantly lower than the baseline in group. The only significant decrease in the HR of the patients in group S was at the tenth minute following caudal injection. The decrease in HR with drug injection has no value to predict the success of caudal block under sevoflurane anesthesia. (author)

The slant of the forehead as a craniofacial feature of impulsiveness

Directory of Open Access Journals (Sweden)

J. David Guerrero-Apolo

2018-03-01

Full Text Available Objective: Impulsiveness has been the subject of much research, but little is known about the possible relationship between craniofacial anatomy and impulsiveness. The present study was designed to investigate the relationship between one aspect of craniofacial structure (the angle of inclination of the forehead and impulsiveness. Method: Photographs in profile were obtained from 131 volunteers who had been fined for driving at high speed and were undergoing a court-mandated driving license point-recovery course. They completed the Barratt Impulsiveness Scale (BIS-11, the Impulsive Behavior Scale (UPPS-P, and Zuckerman’s Sensation Seeking Scale (V. The angle of the slant of the forehead was measured with a photographic support and a protractor. Results: High positive concordance was found between forehead inclination and 14 out of the 15 impulsiveness factors studied. Conclusions: The angle of inclination of the forehead was significantly associated with self-reported impulsiveness in this sample of traffic violators.

Effectiveness of caudal septal extension graft application in endonasal septoplasty

Directory of Open Access Journals (Sweden)

Yunus Karadavut

Full Text Available Abstract Introduction Septal deviation is a common disease seen in daily otorhinolaryngology practice and septoplasty is a commonly performed surgical procedure. Caudal septum deviation is also a challenging pathology for ear, nose, and throat specialists. Many techniques are defined for caudal septal deviation. Objective To evaluate the effectiveness of caudal septal extension graft (CSEG application in patients who underwent endonasal septoplasty for a short and deviated nasal septum. Methods Forty patients with nasal septal deviation, short nasal septum, and weak nasal tip support who underwent endonasal septoplasty with or without CSEG placement between August 2012 and June 2013 were enrolled in this study. Twenty patients underwent endonasal septoplasty with CSEG placement. The rest of the group, who rejected auricular or costal cartilage harvest for CSEG placement, underwent only endonasal septoplasty without any additional intervention. Using the Nasal Obstruction Symptom Evaluation (NOSE and Rhinoplasty Outcome Evaluation (ROE questionnaires, pre- and post-operative acoustic rhinometer measurements were evaluated to assess the effect of CESG placement on nasal obstruction. Results In the control group, preoperative and postoperative minimal cross-sectional areas (MCA1 were 0.44 ± 0.10 cm2 and 0.60 ± 0.11 cm2, respectively (p < 0.001. In the study group, pre- and postoperative MCA1 values were 0.45 ± 0.16 cm2 and 0.67 ± 0.16 cm2, respectively (p < 0.01. In the control group, the nasal cavity volume (VOL1 value was 1.71 ± 0.21 mL preoperatively and 1.94 ± 0.17 mL postoperatively (p < 0.001. In the study group, pre- and postoperative VOL1s were 1.72 ± 0.15 mL and 1.97 ± 0.12 mL, respectively (p < 0.001. Statistical analysis of postoperative MCA1 and VOL1 values in the study and the control groups could not detect any significant intergroup difference (p = 0.093 and 0.432, respectively. In the study group, mean nasolabial angles were

Comparison of experimental slant electron content and IRI model for moderate solar activity conditions

International Nuclear Information System (INIS)

Cabrera, M.A.; Ezquer, R.G.; Mosert, M.; Jadur, C.A.

2002-01-01

The International Reference Ionosphere model only gives the vertical electron content (VTEC). In this paper the slant electron content (SEC) for the ATS 6 satellite - Palehua (21.4 deg. N, 201.9 deg. E) radio signal path for a middle solar activity year is calculated. To this end, IRI model is used to obtain the electron density at different points of the signal path. Equinoxes and solstices are considered. Measurements obtained with Faraday rotation technique at Palehua are compared with the modelled values. Although overestimation was observed for night hours, the results show good SEC predictions for several hours at period of maximum ionisation, suggesting that would be possible to model the STEC using IRI. (author)

Black holes

International Nuclear Information System (INIS)

Feast, M.W.

1981-01-01

This article deals with two questions, namely whether it is possible for black holes to exist, and if the answer is yes, whether we have found any yet. In deciding whether black holes can exist or not the central role in the shaping of our universe played by the forse of gravity is discussed, and in deciding whether we are likely to find black holes in the universe the author looks at the way stars evolve, as well as white dwarfs and neutron stars. He also discusses the problem how to detect a black hole, possible black holes, a southern black hole, massive black holes, as well as why black holes are studied

Caudal duplication syndrome: imaging evaluation of a rare entity in an adult patient

Directory of Open Access Journals (Sweden)

Tianshen Hu, BS

2016-03-01

Full Text Available Several theories have been put forth to explain the complex yet symmetrical malformations and the myriad of clinical presentations of caudal duplication syndrome. Hereby, reported case is a 28-year-old female, gravida 2 para 2, with congenital caudal malformation who has undergone partial reconstructive surgeries in infancy to connect her 2 colons. She presented with recurrent left lower abdominal pain associated with nausea, vomiting, and subsequent feculent anal discharge. Imaging reveals duplication of the urinary bladder, urethra, and colon with with cloacal malformations and fistulae from the left-sided cloaca, uterus didelphys with separate cervices and vaginal canals, right-sided aortic arch and descending thoracic aorta, and dysraphic midline sacrococcygeal defect. Hydronephrosis of the left kidney with left hydroureter and inflammation of one of the colons were suspected to be the cause of the patient’s acute complaints. She improved symptomatically over the course of her hospitalization stay with conservative treatments. The management for this syndrome is individualized and may include surgical intervention to fuse or excise the duplicated organs.

Frequency scaling of slant-path atmospheric attenuation in the absence of rain for millimeter-wave links

Science.gov (United States)

Lucas-Vegas, María. José; Riera, José Manuel

2016-11-01

Broadband satellite communications systems, either used for broadcast or fixed satellite services, have grown continuously in recent years. This has led to the use of higher frequency bands, from the Ku (14/11 GHz) to the Ka band (30/20 GHz) in the last decade, and with the expectation of using the Q/V band (50/40 GHz) and even the W band (75-110 GHz) in the future. As frequency increases, radio wave propagation effects in the slant-path within the troposphere are becoming more and more relevant. The objective of this research is the proposal of frequency scaling approximations for the total attenuation in the absence of rain, a condition that occurs during the highest percentages of time, usually more than 95% in temperate climates. There is a strong relationship between total attenuation at different frequencies, as it arises from the same physical phenomena, namely, the presence of oxygen, water vapor, and clouds in the slant path. This strong relationship allows frequency scaling estimations to be proposed. In particular, polynomials for instantaneous frequency scaling of total attenuation under these conditions have been calculated for a set of frequencies in the range 10-100 GHz, based on atmospheric profiles of 60 sites from all over the world and physical models of attenuation. Global polynomials are provided for the 72 combinations of nine significant frequencies, which can be used to estimate attenuation at a frequency band from its known value at a different one. Refined expressions have also been calculated for different climatic zones, providing more precise estimations.

Continuous blood fractionation using an array of slanted grooves

Science.gov (United States)

Bernate, Jorge A.; Chengxun, Liu; Lagae, Liesbet; Drazer, German

2011-11-01

Blood is a complex fluid having different specialized biological functions and containing a plethora of clinical information. The separation of different blood components is a crucial step in many research and clinical applications. In this work we take advantage of the flow characteristics in microfluidic devices in which the bottom surface is patterned with slanted rectangular grooves to continuously fractionate blood. We exploit the flow in the vicinity of the patterned surface when the dimensions of the grooves are much smaller than the dimensions of the main channel. In these devices, we observed that the grooves act as open channels guiding flow along them with the flow over them being in the direction of the main channel. We present experiments in which the different blood components are deflected laterally to a different extent by the flow along the grooves depending on their sedimentation velocity, which allows their continuous fractionation. In particular, the heavier red blood cells experience the largest deflection while the lighter white blood cells deflect the least, allowing their passive and minimally invasive isolation. In addition, this fluidic platform can also be used to separate magnetically labeled circulating cancer cells which can be retained in the flow along the grooves using a sufficiently strong magnetic force.

σ-holes and π-holes: Similarities and differences.

Science.gov (United States)

Politzer, Peter; Murray, Jane S

2018-04-05

σ-Holes and π-holes are regions of molecules with electronic densities lower than their surroundings. There are often positive electrostatic potentials associated with them. Through these potentials, the molecule can interact attractively with negative sites, such as lone pairs, π electrons, and anions. Such noncovalent interactions, "σ-hole bonding" and "π-hole bonding," are increasingly recognized as being important in a number of different areas. In this article, we discuss and compare the natures and characteristics of σ-holes and π-holes, and factors that influence the strengths and locations of the resulting electrostatic potentials. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Rostro-caudal and dorso-ventral gradients in medial and lateral prefrontal cortex during cognitive control of affective and cognitive interference.

Science.gov (United States)

Rahm, Christoffer; Liberg, Benny; Wiberg-Kristoffersen, Maria; Aspelin, Peter; Msghina, Mussie

2013-04-01

Characterizing the anatomical substrates of major brain functions such as cognition and emotion is of utmost importance to the ongoing efforts of understanding the nature of psychiatric ailments and their potential treatment. The aim of our study was to investigate how the brain handles affective and cognitive interferences on cognitive processes. Functional magnetic resonance imaging investigation was performed on healthy individuals, comparing the brain oxygenation level dependent activation patterns during affective and cognitive counting Stroop tasks. The affective Stroop task activated rostral parts of medial prefrontal cortex (PFC) and rostral and ventral parts of lateral PFC, while cognitive Stroop activated caudal parts of medial PFC and caudal and dorsal parts of lateral PFC. Our findings suggest that the brain may handle affective and cognitive interference on cognitive processes differentially, with affective interference preferentially activating rostral and ventral PFC networks and cognitive interference activating caudal and dorsal PFC networks. © 2013 The Authors. Scandinavian Journal of Psychology © 2013 The Scandinavian Psychological Associations.

Hydrodynamics of a robotic fish tail: effects of the caudal peduncle, fin ray motions and the flow speed.

Science.gov (United States)

Ren, Ziyu; Yang, Xingbang; Wang, Tianmiao; Wen, Li

2016-02-08

Recent advances in understanding fish locomotion with robotic devices have included the use of biomimetic flapping based and fin undulatory locomotion based robots, treating two locomotions separately from each other. However, in most fish species, patterns of active movements of fins occur in concert with the body undulatory deformation during swimming. In this paper, we describe a biomimetic robotic caudal fin programmed with individually actuated fin rays to mimic the fin motion of the Bluegill Sunfish (Lepomis macrochirus) and coupled with heave and pitch oscillatory motions adding to the robot to mimic the peduncle motion which is derived from the undulatory fish body. Multiple-axis force and digital particle image velocimetry (DPIV) experiments from both the vertical and horizontal planes behind the robotic model were conducted under different motion programs and flow speeds. We found that both mean thrust and lift could be altered by changing the phase difference (φ) from 0° to 360° between the robotic caudal peduncle and the fin ray motion (spanning from 3 mN to 124 mN). Notably, DPIV results demonstrated that the caudal fin generated multiple wake flow patterns in both the vertical and horizontal planes by varying φ. Vortex jet angle and thrust impulse also varied significantly both in these two planes. In addition, the vortex shedding position along the spanwise tail direction could be shifted around the mid-sagittal position between the upper and lower lobes by changing the phase difference. We hypothesize that the fish caudal fin may serve as a flexible vectoring propeller during swimming and may be critical for the high maneuverability of fish.

The use of tubular retractors for translaminar discectomy for cranially and caudally extruded discs

Directory of Open Access Journals (Sweden)

Arvind G Kulkarni

2018-01-01

Full Text Available Background: The conventional interlaminar approach is adequate for access to most disc herniations in lumbar spine surgery. The access to cranially and caudally migrated disc fragments, by conventional interlaminar fenestration, requires an extension of the fenestration with the potential destruction of the facet joint complex and consequent postsurgical instability. To describe the technique and results of the translaminar technique of targeted discectomy using tubular retractors for the surgical treatment of cranially and caudally extruded discs. Materials and Methods: The study period extended from January 2008 to December 2014. All patients with lumbar herniated discs who failed conservative management were selected for surgery and underwent routine erect radiographs and magnetic resonance imaging (MRI of the lumbar spine. The patients with cranially or caudally migrated discs were included in this study. The technique involves approaching migrated disc through an oval window (sculpted through an 18 mm tubular retractor using a burr in the lamina precisely over the location of the migrated disc as predicted by the preoperative MRI (inferior lamina for inferior migration and superior lamina for superior migration. The perioperative parameters studied were operative time, blood loss, complications, Oswestry Disability Index (ODI, and visual analog scale (VAS for leg pain before surgery and at last followup. In the study, 4 patients underwent a postoperative computed tomography-scan with a three-dimensional reconstruction to visualize the oval window and to rule out any pars fracture. All technical difficulties and complications were analyzed. Results: 17 patients in the age group of 41–58 years underwent the translaminar technique of targeted discectomy. The migration of disc was cranial in 12 patients and caudal in 5 patients. Fourteen of the affected discs were at the L4–L5 level and three were at the L5-S1 level. The mean VAS (leg pain

Quantitative analysis of neurological effects induced by cranio-caudal gamma-irradiation of rats

International Nuclear Information System (INIS)

Davydov, B.I.; Ushakov, I.B.; Karpov, V.N.

1987-01-01

A study was made of the frequency and duration of neurological disorders after cranio-caudal irradiation of rats with doses of 7.5-500 Gy delivered to the head. As the mean effective dose increased the neurological disorders occurred in the following order: tremor, rotatory movements hyperkinesia, opisthotonos, and convulsions. The europhysiological disorders observed were subjected to a pathophysiological analysis

Black hole astrophysics

International Nuclear Information System (INIS)

Blandford, R.D.; Thorne, K.S.

1979-01-01

Following an introductory section, the subject is discussed under the headings: on the character of research in black hole astrophysics; isolated holes produced by collapse of normal stars; black holes in binary systems; black holes in globular clusters; black holes in quasars and active galactic nuclei; primordial black holes; concluding remarks on the present state of research in black hole astrophysics. (U.K.)

The Effects of Single-Dose Rectal Midazolam Application on Postoperative Recovery, Sedation, and Analgesia in Children Given Caudal Anesthesia Plus Bupivacaine

Directory of Open Access Journals (Sweden)

Sedat Saylan

2014-01-01

Full Text Available Background. This study aimed to compare the effects of rectal midazolam addition after applying bupivacaine and caudal anesthesia on postoperative analgesia time, the need for additional analgesics, postoperative recovery, and sedation and to find out its adverse effects in children having lower abdominal surgery. Methods. 40 children between 2 and 10 years of ASA I-II were randomized, and they received caudal anesthesia under general anesthesia. Patients underwent the application of caudal block in addition to saline and 1 mL/kg bupivacaine 0.25%. In the postoperative period, Group C (n = 20 was given 5 mL saline, and Group M (n = 20 was given 0.30 mg/kg rectal midazolam diluted with 5 mL saline. Sedation scale and postoperative pain scale (CHIPPS of the patients were evaluated. The patients were observed for their analgesic need, first analgesic time, and adverse effects for 24 hours. Results. Demographic and hemodynamic data of the two groups did not differ. Postoperative sedation scores in both groups were significantly lower compared with the preoperative period. There was no significant difference between the groups in terms of sedation and sufficient analgesia. Conclusions. We conclude that caudal anesthesia provided sufficient analgesia in peroperative and postoperative periods, and rectal midazolam addition did not create any differences. This trial is registered with ClinicalTrials.gov NCT02127489.

Histological variations in myoepithelial cells and arrectores pilorum muscles among caudal, metatarsal and preorbital glands in Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884).

Science.gov (United States)

Ozaki, Nobuo; Suzuki, Masatsugu; Ohtaishi, Noriyuki

2004-03-01

The morphological characteristics of myoepithelial cells and arrectores pilorum muscles were investigated in caudal, metatarsal and preorbital glands of Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884) using immunohistochemistry for alpha-smooth muscle actin. In the metatarsal, preorbital and general skin glands, myoepithelial cell layers continuously embraced the secretory epithelium, while in the caudal gland, discontinuous myoepithelial cell rows surrounded the apocrine tubules. There was a trend that the widths of the myoepithelial cells of the caudal and preorbital glands appeared to be thinner than those of the metatarsal and general skin glands. In the metatarsal gland, the arrectores pilorum muscles were highly developed and considerably larger than those in other skin glands.

Comparison of the therapeutic effect between a transforminal along with a caudal epidural injection, as well as two-level transforaminal epidural injections ina radiculopathy patient

International Nuclear Information System (INIS)

Hwang, Jung Han; Hwang, Cheol Mog; Cho, Young Jun; Kim, Keun Won; Kim, Young Joong; Seo, Jae Young; Lim, Seong Joo; Kang, Byeong Seong

2017-01-01

The aim of this study was to evaluate the therapeutic effect of a transforaminal epidural steroid injection (TFESI) along with a caudal epidural steroid injection (ESI), compared to two-level TFESIs in a multi-level radiculopathy patient. A total of 895 lumbar ESIs were performed in 492 patients with multi-level radiculopathy from January 2012 to January 2015. Before injections were performed, the initial Numeric Rating Scale (NRS) score was assessed in all patients, categorized into no pain (excellent), mild (good, NRS: 1-3), moderate (fair, NRS: 4-6), and severe pain (poor, NRS: 7-10). Therapeutic effects were examined for two groups: one-level TFESI along with caudal and ESI two-level TFESIs. Patient outcomes were assessed by NRS in a serial follow-up at one, three, and six months. One TFESI along with caudal ESI was performed in 274 patients and two TFESIs for 218. For the former group with one TFESI along with caudal ESI, excellent results were shown: 219 (79.9%) patients after one month, 200 (72.9%) after three, and 193 (70.4%) after six months. In the patient group with two TFESIs (n = 218) the outcomes were also very good: 152 (69.7%) after one month, 131 (60.0%) after three months, and 123 (56.4%) patients after six months. The therapeutic effect of one TFESI along with caudal ESI was better than two TFESIs in for one, threes, and six months (p < 0.01). Transforaminal epidural steroid with caudal epidural injection is a more effective tool for lumbosacral radiculopathy than two level transforaminal injections in multi-level radiculopathy patients

Comparison of the therapeutic effect between a transforminal along with a caudal epidural injection, as well as two-level transforaminal epidural injections ina radiculopathy patient

Energy Technology Data Exchange (ETDEWEB)

Hwang, Jung Han; Hwang, Cheol Mog; Cho, Young Jun; Kim, Keun Won; Kim, Young Joong; Seo, Jae Young; Lim, Seong Joo [Dept. of Diagnostic Radiology, Konyang University Hospital, Deajeon (Korea, Republic of); Kang, Byeong Seong [Dept. of Radiology, University of Ulsan College of Medicine, Ulsan University Hospital, Ulsan (Korea, Republic of)

2017-01-15

The aim of this study was to evaluate the therapeutic effect of a transforaminal epidural steroid injection (TFESI) along with a caudal epidural steroid injection (ESI), compared to two-level TFESIs in a multi-level radiculopathy patient. A total of 895 lumbar ESIs were performed in 492 patients with multi-level radiculopathy from January 2012 to January 2015. Before injections were performed, the initial Numeric Rating Scale (NRS) score was assessed in all patients, categorized into no pain (excellent), mild (good, NRS: 1-3), moderate (fair, NRS: 4-6), and severe pain (poor, NRS: 7-10). Therapeutic effects were examined for two groups: one-level TFESI along with caudal and ESI two-level TFESIs. Patient outcomes were assessed by NRS in a serial follow-up at one, three, and six months. One TFESI along with caudal ESI was performed in 274 patients and two TFESIs for 218. For the former group with one TFESI along with caudal ESI, excellent results were shown: 219 (79.9%) patients after one month, 200 (72.9%) after three, and 193 (70.4%) after six months. In the patient group with two TFESIs (n = 218) the outcomes were also very good: 152 (69.7%) after one month, 131 (60.0%) after three months, and 123 (56.4%) patients after six months. The therapeutic effect of one TFESI along with caudal ESI was better than two TFESIs in for one, threes, and six months (p < 0.01). Transforaminal epidural steroid with caudal epidural injection is a more effective tool for lumbosacral radiculopathy than two level transforaminal injections in multi-level radiculopathy patients.

Origens e distribuições das artérias mesentéricas cranial e caudal em fetos de javalis (Sus scrofa scrofa, Linnaeus – 1758

Directory of Open Access Journals (Sweden)

Andrea Regina Abrantes Gomes

2013-01-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2013v26n1p159 Estudou-se o comportamento anatômico das artérias mesentéricas cranial e caudal em 21 fetos de javalis, fêmeas e machos, nos quais foi injetada, através da aorta torácica, solução de Neoprene Látex “450”, corada com pigmento específico e, em seguida, eles foram fixados em solução de formol a 10%. A análise dos resultados permitiu afirmar que a artéria mesentérica cranial originou-se da aorta abdominal, caudalmente à artéria celíaca, emitiu ramos adrenais direito e esquerdo, pancreáticos, e as artérias pancreático-duodenal caudal, jejunais, cólicas média e direita, e ileocecocólica. A artéria mesentérica caudal surgiu da aorta abdominal, de seu terço caudal, e emitiu as artérias cólica esquerda e retal cranial. Foram verificadas anastomoses entre artérias jejunais, cólica esquerda e retal cranial, e cólicas esquerda e média. Nas três espécies, as artérias mesentéricas cranial e caudal, pancreático-duodenal caudal, jejunais, cólicas direita e média, e ileocecocólica apresentaram padrões vasculares semelhantes, visto que as diferenças quanto a emissão de ramos ou surgimento isolado ou em tronco comum não alteraram o suprimento sanguíneo.

Segmental distribution of high-volume caudal anesthesia in neonates, infants, and toddlers as assessed by ultrasonography.

Science.gov (United States)

Lundblad, Märit; Lönnqvist, Per-Arne; Eksborg, Staffan; Marhofer, Peter

2011-02-01

The aim of this prospective, age-stratified, observational study was to determine the cranial extent of spread of a large volume (1.5 ml·kg(-1) , ropivacaine 0.2%), single-shot caudal epidural injection using real-time ultrasonography. Fifty ASA I-III children were included in the study, stratified in three age groups; neonates, infants (1-12 months), and toddlers (1-4 years). The caudal blocks were performed during ultrasonographic observation of the spread of local anesthetic (LA) in the epidural space. A significant inverse relationship was found between age, weight, and height, and the maximal cranial level reached by 1.5 ml·kg(-1) of LA. In neonates, 93% of the blocks reached a cranial level of ≥Th12 vs 73% and 25% in infants and toddlers, respectively. Based on our data, a predictive equation of segmental spread was generated: Dose (ml/spinal segment) = 0.1539·(BW in kg)-0.0937. This study found an inverse relationship between age, weight, and height and the number of segments covered by a caudal injection of 1.5 ml·kg(-1) of ropivacaine 0.2% in children 0-4 years of age. However, the cranial spread of local anesthetics within the spinal canal as assessed by immediate ultrasound visualization was found to be in poor agreement with previously published predictive equations that are based on actual cutaneous dermatomal testing. © 2010 Blackwell Publishing Ltd.

Systematization, description and territory of the caudal cerebral artery of the brain in broad-snouted Caiman (Caiman latirostris

Directory of Open Access Journals (Sweden)

Lygia Almeida

2011-09-01

Full Text Available Thirty heads with the neck segment of Caiman latirostris were used. The animals were provided from a creation center called Mister Caiman, under the authorization of the Brazilian Institute of Environment and Renewable Natural Resources (Ibama. Animals were sacrificed according to the slaughtering routine of the abattoir, and the heads were sectioned at the level of the third cervical vertebra. The arterial system was washed with cold saline solution, with drainage through jugular veins. Subsequently, the system was filled with red colored latex injection. Pieces were than fixed in 20% formaldehyde, for seven days. The brains were removed, with a spinal cord segment, the duramater removed and the arteries dissected. At the level of the hypophysis, the internal carotid artery gave off a rostral branch, and a short caudal branch, continuing, naturally, as the caudal cerebral artery. This artery projected laterodorsalwards and, as it overpassed the optic tract, gave off its I (the first central branch. Penetrated in the cerebral transverse fissure, emitting the diencephalic artery and next its II (second central branch. Still inside the fissure, originated occipital hemispheric branches and a pineal branch. Emerged from the cerebral transverse fissure, over the occipital pole of the cerebral hemisphere. Projected rostralwards, sagital to the cerebral longitudinal fissure, as interhemispheric artery. This artery gave off medial and convex hemispheric branches to the respective surfaces of the cerebral hemispheres, anastomosed with its contralateral homologous, forming the common ethmoidal artery. This artery entered the fissure between the olfactory peduncles, emerging ventrally and dividing into ethmoidal arteries, right and left, which progressed towards the nasal cavities, vascularizing them. The territory of the caudal cerebral artery included the most caudal area of the base of the cerebral hemisphere, its convex surface, the olfactory

Effect of magnesium added to local anesthetics for caudal anesthesia on postoperative pain in pediatric surgical patients: A systematic review and meta-analysis with Trial Sequential Analysis.

Science.gov (United States)

Kawakami, Hiromasa; Mihara, Takahiro; Nakamura, Nobuhito; Ka, Koui; Goto, Takahisa

2018-01-01

Magnesium has been investigated as an adjuvant for neuraxial anesthesia, but the effect of caudal magnesium on postoperative pain is inconsistent. The aim of this systematic review and meta-analysis was to evaluate the analgesic effect of caudal magnesium. We searched six databases, including trial registration sites. Randomized clinical trials reporting the effect of caudal magnesium on postoperative pain after general anesthesia were eligible. The risk ratio for use of rescue analgesics after surgery was combined using a random-effects model. We also assessed adverse events. The I2 statistic was used to assess heterogeneity. We assessed risk of bias with Cochrane domains. We controlled type I and II errors due to sparse data and repetitive testing with Trial Sequential Analysis. We assessed the quality of evidence with GRADE. Four randomized controlled trials (247 patients) evaluated the need for rescue analgesics. In all four trials, 50 mg of magnesium was administered with caudal ropivacaine. The results suggested that the need for rescue analgesia was reduced significantly by caudal magnesium administration (risk ratio 0.45; 95% confidence interval 0.24-0.86). There was considerable heterogeneity as indicated by an I2 value of 62.5%. The Trial Sequential Analysis-adjusted confidence interval was 0.04-5.55, indicating that further trials are required. The quality of evidence was very low. The rate of adverse events was comparable between treatment groups. Caudal magnesium may reduce the need for rescue analgesia after surgery, but further randomized clinical trials with a low risk of bias and a low risk of random errors are necessary to assess the effect of caudal magnesium on postoperative pain and adverse events. University Hospital Medical Information Network Clinical Trials Registry UMIN000025344.

SHORT-PULSE ELECTROMAGNETIC TRANSPONDER FOR HOLE-TO-HOLE USE.

Science.gov (United States)

Wright, David L.; Watts, Raymond D.; Bramsoe, Erik

1983-01-01

Hole-to-hole observations were made through nearly 20 m of granite using an electromagnetic transponder (an active reflector) in one borehole and a single-hole short-pulse radar in another. The transponder is inexpensive, operationally simple, and effective in extending the capability of a short-pulse borehole radar system to allow hole-to-hole operation without requiring timing cables. A detector in the transponder senses the arrival of each pulse from the radar. Each pulse detection triggers a kilovolt-amplitude pulse for retransmission. The transponder 'echo' may be stronger than that of a passive reflector by a factor of as much as 120 db. The result is an increase in range capability by a factor which depends on attenuation in the medium and hole-to-hole wavepath geometry.

A randomized double-blinded comparison between dexmedetomidine and clonidine as an adjuvant to caudal ropivacaine in children for below umbilical surgery

Directory of Open Access Journals (Sweden)

Ganapathi Mavuri

2017-01-01

Full Text Available Background: Alpha-2 adenoreceptors as an adjuvant to local anesthetic during caudal analgesia in children prolongs the duration of analgesia. This study was designed to compare the analgesic efficacy and adverse effects of dexmedetomidine and clonidine when added to ropivacaine for caudal analgesia in children undergoing lower abdominal surgeries. Methods: In a prospective study, Seventy-eight children received block with either 0.2% ropivacaine 1.5 mg/kg (Group R; n = 26 or 0.2% ropivacaine 1.5 mg/kg + 1 mcg/kg clonidine (Group RC; n = 26 or 0.2% ropivacaine 1.5 mg/kg + dexmedetomidine 1 mcg/kg (Group RD; n = 26. Results: Duration of analgesia was 7.15 ± 1.00 h in Group R, 11.57 ± 1.27 h in Group R + C, and 14.73 ± 1.53 h in Group R + D (P 0.05. Conclusion: Addition of clonidine and dexmedetomidine to caudal ropivacaine significantly prolongs the duration of analgesia without adverse effects.

Black holes

OpenAIRE

Brügmann, B.; Ghez, A. M.; Greiner, J.

2001-01-01

Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries.

Unique caudal plumage of Jeholornis and complex tail evolution in early birds

OpenAIRE

O’Connor, Jingmai; Wang, Xiaoli; Sullivan, Corwin; Zheng, Xiaoting; Tubaro, Pablo; Zhang, Xiaomei; Zhou, Zhonghe

2013-01-01

The Early Cretaceous bird Jeholornis was previously only known to have a distally restricted ornamental frond of tail feathers. We describe a previously unrecognized fan-shaped tract of feathers situated dorsal to the proximal caudal vertebrae. The position and morphology of these feathers is reminiscent of the specialized upper tail coverts observed in males of some sexually dimorphic neornithines. As in the neornithine tail, the unique “two-tail” plumage in Jeholornis probably evolved as th...

GATA-3 is involved in the development of serotonergic neurons in the caudal raphe nuclei

NARCIS (Netherlands)

J. van der Wees (Jacqueline); A. Karis (Alar); E. Goedknegt; M. Rutteman; F.G. Grosveld (Frank); J.H. van Doorninck (Hikke); C.I. de Zeeuw (Chris)

1999-01-01

textabstractAbstract The GATA-3 transcription factor shows a specific and restricted expression pattern in the developing and adult mouse brain. In the present study we investigated the role of GATA-3 in the caudal raphe system, which is known to operate as a modulator of motor activity. We

Neutrino constraints that transform black holes into grey holes

International Nuclear Information System (INIS)

Ruderfer, M.

1982-01-01

Existing black hole theory is found to be defective in its neglect of the physical properties of matter and radiation at superhigh densities. Nongravitational neutrino effects are shown to be physically relevant to the evolution of astronomical black holes and their equations of state. Gravitational collapse to supernovae combined with the Davis and Ray vacuum solution for neutrinos limit attainment of a singularity and require black holes to evolve into ''grey holes''. These allow a better justification than do black holes for explaining the unique existence of galactic masses. (Auth.)

Primary black holes

International Nuclear Information System (INIS)

Novikov, I.; Polnarev, A.

1981-01-01

Proves are searched for of the formation of the so-called primary black holes at the very origin of the universe. The black holes would weigh less than 10 13 kg. The formation of a primary black hole is conditional on strong fluctuations of the gravitational field corresponding roughly to a half of the fluctuation maximally permissible by the general relativity theory. Only big fluctuations of the gravitational field can overcome the forces of the hot gas pressure and compress the originally expanding matter into a black hole. Low-mass black holes have a temperature exceeding that of the black holes formed from stars. A quantum process of particle formation, the so-called evaporation takes place in the strong gravitational field of a black hole. The lower the mass of the black hole, the shorter the evaporation time. The analyses of processes taking place during the evaporation of low-mass primary black holes show that only a very small proportion of the total mass of the matter in the universe could turn into primary black holes. (M.D.)

Norepinephrine accumulation by the rat caudal artery in the presence of hypertensive plasma

International Nuclear Information System (INIS)

Freas, W.; Thompson, D.A.; Hart, J.L.; Muldoon, S.M.

1986-01-01

We have partially isolated endogenous factors from canine plasma which inhibit 3 H-norepinephrine (NE) accumulation by the canine saphenous vein. The purpose of this study is to determine if these circulating factors may account for the observed differences in 3 H-NE uptake by hypertensive and normotensive blood vessels. Three models of hypertension were examined in this study. Blood vessels were compared from SHR and WKY rats, deoxycorticosterone acetate (DOCA) and control rats, and reduced renal mass (RRM) and control rats. There was no significant difference in 3 H-NE accumulation between blood vessels obtained from RRM and paired control rats. However, both the SHR and DOCA hypertensive caudal arteries and aorta accumulated significantly more 3 H-NE than their corresponding control tissues. There was not a significant change in 3 H-NE accumulation between hypertensive and control vena cava and mesenteric arteries. Normotensive and hypertensive plasma inhibited 3 H-NE accumulation by the rat caudal artery. However, there was not a correlation between blood pressure of plasma donor rats and accumulation of 3 H-NE. Therefore, although there are differences in 3 H-NE accumulation between hypertensive and normotensive blood vessels, plasma does not contain a factor responsible for this observed difference

From binary black hole simulation to triple black hole simulation

International Nuclear Information System (INIS)

Bai Shan; Cao Zhoujian; Han, Wen-Biao; Lin, Chun-Yu; Yo, Hwei-Jang; Yu, Jui-Ping

2011-01-01

Black hole systems are among the most promising sources for a gravitational wave detection project. Now, China is planning to construct a space-based laser interferometric detector as a follow-on mission of LISA in the near future. Aiming to provide some theoretical support to this detection project on the numerical relativity side, we focus on black hole systems simulation in this work. Considering the globular galaxy, multiple black hole systems also likely to exist in our universe and play a role as a source for the gravitational wave detector we are considering. We will give a progress report in this paper on our black hole system simulation. More specifically, we will present triple black hole simulation together with binary black hole simulation. On triple black hole simulations, one novel perturbational method is proposed.

Phase transition for black holes with scalar hair and topological black holes

International Nuclear Information System (INIS)

Myung, Yun Soo

2008-01-01

We study phase transitions between black holes with scalar hair and topological black holes in asymptotically anti-de Sitter spacetimes. As the ground state solutions, we introduce the non-rotating BTZ black hole in three dimensions and topological black hole with hyperbolic horizon in four dimensions. For the temperature matching only, we show that the phase transition between black hole with scalar hair (Martinez-Troncoso-Zanelli black hole) and topological black hole is second-order by using differences between two free energies. However, we do not identify what order of the phase transition between scalar and non-rotating BTZ black holes occurs in three dimensions, although there exists a possible decay of scalar black hole to non-rotating BTZ black hole

Caudal dysplasia syndrome and sirenomelia: are they part of a spectrum?

Science.gov (United States)

Bruce, Jocelyn H; Romaguera, Rita L; Rodriguez, Maria M; González-Quintero, Víctor H; Azouz, E Michel

2009-01-01

Caudal dysplasia syndrome (CDS) is associated with hypoplastic lower extremities, caudal vertebrae, sacrum, neural tube, and urogenital organs. Sirenomelia is characterized by a single lower extremity, absent sacrum, urogenital anomalies, and imperforate anus. There is controversy in the medical literature about whether sirenomelia and CDS are part of the spectrum of the same malformation. Patients with CDS and sirenomelia were identified from our pathology files from 1991 to 2006. Maternal history, pathologic examination, and radiographs were collected and tabulated. We found 9 cases with CDS and 6 with sirenomelia. Fully 7 of 9 patients with CDS (77.7%) versus none of sirenomelic babies were infants of diabetic mothers. Congenital heart disease was present in 5 patients with CDS (55.5%) and none of the infants with sirenomelia. Of 9 children with CDS 2 (22.2%) had bilateral renal agenesis versus 66% of sirenomelics. Single umbilical artery was found in 33% of cases with CDS and 100% of children with sirenomelia. External genitalia were ambiguous in 2 of 9 patients (22.2%) with CDS and in all patients with sirenomelia. Imperforate anus was found in 10 cases (66.6%) divided as 4 of 9 babies with CDS (44.4%) and all patients with sirenomelia. Three patients with CDS had concomitant maternal diabetes mellitus and chronic hypertension. These babies also had cleft lip and palate. Congenital heart disease was found in 55.5% of cases with CDS and none of the children with sirenomelia. We conclude that although CDS and sirenomelia share many similar features, they are two different entities.

Black Holes

OpenAIRE

Townsend, P. K.

1997-01-01

This paper is concerned with several not-quantum aspects of black holes, with emphasis on theoretical and mathematical issues related to numerical modeling of black hole space-times. Part of the material has a review character, but some new results or proposals are also presented. We review the experimental evidence for existence of black holes. We propose a definition of black hole region for any theory governed by a symmetric hyperbolic system of equations. Our definition reproduces the usu...

Ultrasound guided TAP block versus ultrasound guided caudal block for pain relief in children undergoing lower abdominal surgeries

Directory of Open Access Journals (Sweden)

Wafaa Mohamed Alsadek

2015-04-01

Conclusion: TAP block and caudal block under ultrasound guidance proved to be safe with no recorded complications either intra or postoperatively. Patient and parent satisfaction was markedly observed in case of TAP block.

Towards 2D field-flow fractionation - Vector separation over slanted open cavities

Science.gov (United States)

Bernate, Jorge A.; Yang, Mengfei; Zhao, Hong; Risbud, Sumedh; Paul, Colin; Dallas, Matthew; Konstantopoulos, Konstantinos; Drazer, German; Shaqfeh, Eric S. G.

2013-11-01

Planar microfluidic platforms for vector chromatography, in which different species fan out in different directions and can be continuously sorted, are particularly promising for the high throughput separation of multicomponent mixtures. We carry out a computational study of the vector separation of dilute suspensions of rigid and flexible particles transported by a pressure-driven flow over an array of slanted open cavities. The numerical scheme is based on a Stokes flow boundary integral equation method. The simulations are performed in a periodic system without lateral confinement, relevant to microfluidic devices with negligible recirculation in the main channel. We study the deflection of rigid spherical particles, of flexible capsules as a model of white and red blood cells, and of rigid discoidal particles as a model of platelets. We characterize the deflection of different particles as a function of their size, shape, shear elasticity, their release position, and the geometric parameters of the channel. The simulations provide insight into the separation mechanism and allow the optimization of specific devices depending on the application. Good agreement with experiments is observed.

Low-mass black holes as the remnants of primordial black hole formation.

Science.gov (United States)

Greene, Jenny E

2012-01-01

Bridging the gap between the approximately ten solar mass 'stellar mass' black holes and the 'supermassive' black holes of millions to billions of solar masses are the elusive 'intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ∼10(4)-10(5) M(⊙) black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism.

Hole dephasing caused by hole-hole interaction in a multilayered black phosphorus.

Science.gov (United States)

Li, Lijun; Khan, Muhammad Atif; Lee, Yoontae; Lee, Inyeal; Yun, Sun Jin; Youn, Doo-Hyeb; Kim, Gil-Ho

2017-11-01

We study the magnetotransport of holes in a multilayered black phosphorus in a temperature range of 1.9 to 21.5 K. We observed a negative magnetoresistance at magnetic fields up to 1.5 T. This negative magetoresistance was analyzed by weak localization theory in diffusive regime. At the lowest temperature and the highest carrier density we found a phase coherence length of 48 nm. The linear temperature dependence of the dephasing rate shows that the hole-hole scattering processes with small energy transfer are the dominant contribution in breaking the carrier phase coherence.

Bifurcation from stable holes to replicating holes in vibrated dense suspensions.

Science.gov (United States)

Ebata, H; Sano, M

2013-11-01

In vertically vibrated starch suspensions, we observe bifurcations from stable holes to replicating holes. Above a certain acceleration, finite-amplitude deformations of the vibrated surface continue to grow until void penetrates fluid layers, and a hole forms. We studied experimentally and theoretically the parameter dependence of the holes and their stabilities. In suspensions of small dispersed particles, the circular shapes of the holes are stable. However, we find that larger particles or lower surface tension of water destabilize the circular shapes; this indicates the importance of capillary forces acting on the dispersed particles. Around the critical acceleration for bifurcation, holes show intermittent large deformations as a precursor to hole replication. We applied a phenomenological model for deformable domains, which is used in reaction-diffusion systems. The model can explain the basic dynamics of the holes, such as intermittent behavior, probability distribution functions of deformation, and time intervals of replication. Results from the phenomenological model match the linear growth rate below criticality that was estimated from experimental data.

Black Holes

OpenAIRE

Horowitz, Gary T.; Teukolsky, Saul A.

1998-01-01

Black holes are among the most intriguing objects in modern physics. Their influence ranges from powering quasars and other active galactic nuclei, to providing key insights into quantum gravity. We review the observational evidence for black holes, and briefly discuss some of their properties. We also describe some recent developments involving cosmic censorship and the statistical origin of black hole entropy.

Black hole levitron

International Nuclear Information System (INIS)

Arsiwalla, Xerxes D.; Verlinde, Erik P.

2010-01-01

We study the problem of spatially stabilizing four dimensional extremal black holes in background electric/magnetic fields. Whilst looking for stationary stable solutions describing black holes placed in external fields we find that taking a continuum limit of Denef et al.'s multicenter supersymmetric black hole solutions provides a supergravity description of such backgrounds within which a black hole can be trapped within a confined volume. This construction is realized by solving for a levitating black hole over a magnetic dipole base. We comment on how such a construction is akin to a mechanical levitron.

Noncommutative black holes

Energy Technology Data Exchange (ETDEWEB)

Lopez-DomInguez, J C [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); Obregon, O [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); RamIrez, C [Facultad de Ciencias FIsico Matematicas, Universidad Autonoma de Puebla, PO Box 1364, 72000 Puebla (Mexico); Sabido, M [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico)

2007-11-15

We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole.

Black hole critical phenomena without black holes

Indian Academy of Sciences (India)

large values of Ф, black holes do form and for small values the scalar field ... on the near side of the ridge ultimately evolve to form black holes while those configu- ... The inset shows a bird's eye view looking down on the saddle point.

Search for black holes

International Nuclear Information System (INIS)

Cherepashchuk, Anatolii M

2003-01-01

Methods and results of searching for stellar mass black holes in binary systems and for supermassive black holes in galactic nuclei of different types are described. As of now (June 2002), a total of 100 black hole candidates are known. All the necessary conditions Einstein's General Relativity imposes on the observational properties of black holes are satisfied for candidate objects available, thus further assuring the existence of black holes in the Universe. Prospects for obtaining sufficient criteria for reliably distinguishing candidate black holes from real black holes are discussed. (reviews of topical problems)

A novel approach to brachycephalic syndrome. 3. Isolated laser-assisted turbinectomy of caudal aberrant turbinates (CAT LATE).

Science.gov (United States)

Schuenemann, Riccarda; Pohl, Sabine; Oechtering, Gerhard U

2017-01-01

To describe isolated laser-assisted turbinectomy of caudal aberrant turbinates (CAT LATE) as a new minimally invasive surgical procedure for the treatment of brachycephalic dogs with obstructing caudal aberrant turbinates (CAT). Prospective clinical study. Brachycephalic dogs (24 Pugs, 1 English Bulldog) with CAT but adequate air spaces between the lamellae of the nonobstructing ventral nasal concha. A rhinoscopically guided diode laser fiber introduced from anterior was used to dissect CAT within the nasopharyngeal meatus, while leaving the intranasal turbinates intact. Small grasping forceps were used to extract the dissected CAT from anterior or to push it through the nasopharyngeal meatus for extraction from posterior. Isolated CAT LATE was successfully performed on 32 CAT in 25 dogs. Intranasally applied xylometazoline helped shrink the ventral concha, making the approach and extraction easier. Minor bleeding was the only complication observed. It is possible to remove CAT with endoscopically applied diode-laser energy while leaving the nonobstructing ventral nasal concha intact. © 2017 The American College of Veterinary Surgeons.

Metals in the caudal scutes of Morelet's crocodile (Crocodylus moreletii) from the southern Gulf of Mexico.

Science.gov (United States)

Trillanes, C E; Pérez-Jiménez, J C; Rosíles-Martínez, R; González-Jáuregui, M

2014-10-01

Caudal scutes were collected from 92 Morelet's crocodiles (Crocodylus moreletii) between May and August 2012, in three Wildlife Management and Use Units (UMAs, from its name in Spanish) and three wild sites in Campeche, Mexico. The UMAs are intensive, with an ex situ approach to manage crocodiles in captivity. The concentrations of arsenic, mercury, lead, nickel, cadmium and chromium were analyzed in each sample. As and Pb were detected in all samples, Hg in 86 and Ni in 74. The metal concentrations estimated were higher than most of the concentrations reported for skin, tail tip and caudal scutes in other crocodilians around the world. The concentration of As, Pb and Ni was significantly greater in the free-ranging groups than in the captive groups in UMAs (p < 0.05). Negative linear relationship was estimated between the snout-vent length and the concentration of Pb (in five groups) and Ni (in three groups). In this region C. moreletii is exposed to metals contamination and more studies are necessary to establish if represents a risk to their populations.

A Dancing Black Hole

Science.gov (United States)

Shoemaker, Deirdre; Smith, Kenneth; Schnetter, Erik; Fiske, David; Laguna, Pablo; Pullin, Jorge

2002-04-01

Recently, stationary black holes have been successfully simulated for up to times of approximately 600-1000M, where M is the mass of the black hole. Considering that the expected burst of gravitational radiation from a binary black hole merger would last approximately 200-500M, black hole codes are approaching the point where simulations of mergers may be feasible. We will present two types of simulations of single black holes obtained with a code based on the Baumgarte-Shapiro-Shibata-Nakamura formulation of the Einstein evolution equations. One type of simulations addresses the stability properties of stationary black hole evolutions. The second type of simulations demonstrates the ability of our code to move a black hole through the computational domain. This is accomplished by shifting the stationary black hole solution to a coordinate system in which the location of the black hole is time dependent.

XFEM Modelling of Multi-holes Plate with Single-row and Staggered Holes Configurations

Directory of Open Access Journals (Sweden)

Supar Khairi

2017-01-01

Full Text Available Joint efficiency is the key to composite structures assembly design, good structures response is dependent upon multi-holes behavior as subjected to remote loading. Current benchmarking work were following experimental testing series taken from literature on multi-holes problem. Eleven multi-hole configurations were investigated with various pitch and gage distance of staggered holes and non-staggered holes (single-row holes. Various failure modes were exhibited, most staggered holes demonstrates staggered crack path but non-staggered holes series displayed crack path along net-section plane. Stress distribution were carried out and good agreement were exhibited in experimental observation as reported in the respective literature. Consequently, strength prediction work were carried out under quasi-static loading, most showed discrepancy between 8% -31%, better prediction were exhibited in thicker and non-staggered holes plate combinations.

Black holes will break up solitons and white holes may destroy them

International Nuclear Information System (INIS)

Akbar, Fiki T.; Gunara, Bobby E.; Susanto, Hadi

2017-01-01

Highlights: • What happens if a soliton collides with a black or white hole? • Solitons can pass through black hole horizons, but they will break up into several solitons after the collision. • In the interaction with a white hole horizon, solitons either pass through the horizon or will be destroyed by it. - Abstract: We consider a quantum analogue of black holes and white holes using Bose–Einstein condensates. The model is described by the nonlinear Schrödinger equation with a ‘stream flow’ potential, that induces a spatial translation to standing waves. We then mainly consider the dynamics of dark solitons in a black hole or white hole flow analogue and their interactions with the event horizon. A reduced equation describing the position of the dark solitons was obtained using variational method. Through numerical computations and comparisons with the analytical approximation we show that solitons can pass through black hole horizons even though they will break up into several solitons after the collision. In the interaction with a white hole horizon, we show that solitons either pass through the horizon or will be destroyed by it.

Black holes will break up solitons and white holes may destroy them

Energy Technology Data Exchange (ETDEWEB)

Akbar, Fiki T., E-mail: ftakbar@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10, Bandung, 40132 (Indonesia); Gunara, Bobby E., E-mail: bobby@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10, Bandung, 40132 (Indonesia); Susanto, Hadi, E-mail: hsusanto@essex.ac.uk [Department of Mathematical Sciences, University of Essex, Colchester, CO4 3SQ (United Kingdom)

2017-06-15

Highlights: • What happens if a soliton collides with a black or white hole? • Solitons can pass through black hole horizons, but they will break up into several solitons after the collision. • In the interaction with a white hole horizon, solitons either pass through the horizon or will be destroyed by it. - Abstract: We consider a quantum analogue of black holes and white holes using Bose–Einstein condensates. The model is described by the nonlinear Schrödinger equation with a ‘stream flow’ potential, that induces a spatial translation to standing waves. We then mainly consider the dynamics of dark solitons in a black hole or white hole flow analogue and their interactions with the event horizon. A reduced equation describing the position of the dark solitons was obtained using variational method. Through numerical computations and comparisons with the analytical approximation we show that solitons can pass through black hole horizons even though they will break up into several solitons after the collision. In the interaction with a white hole horizon, we show that solitons either pass through the horizon or will be destroyed by it.

Caged black holes: Black holes in compactified spacetimes. I. Theory

International Nuclear Information System (INIS)

Kol, Barak; Sorkin, Evgeny; Piran, Tsvi

2004-01-01

In backgrounds with compact dimensions there may exist several phases of black objects including a black hole and a black string. The phase transition between them raises questions and touches on fundamental issues such as topology change, uniqueness, and cosmic censorship. No analytic solution is known for the black hole, and moreover one can expect approximate solutions only for very small black holes, while phase transition physics happens when the black hole is large. Hence we turn to numerical solutions. Here some theoretical background to the numerical analysis is given, while the results will appear in a subsequent paper. The goals for a numerical analysis are set. The scalar charge and tension along the compact dimension are defined and used as improved order parameters which put both the black hole and the black string at finite values on the phase diagram. The predictions for small black holes are presented. The differential and the integrated forms of the first law are derived, and the latter (Smarr's formula) can be used to estimate the 'overall numerical error'. Field asymptotics and expressions for physical quantities in terms of the numerical values are supplied. The techniques include the 'method of equivalent charges', free energy, dimensional reduction, and analytic perturbation for small black holes

Alternate Explosions: Collapse and Accretion Events with Red Holes instead of Black Holes

OpenAIRE

Graber, James S.

1999-01-01

A red hole is "just like a black hole" except it lacks an event horizon and a singularity. As a result, a red hole emits much more energy than a black hole during a collapse or accretion event. We consider how a red hole solution can solve the "energy crisis" and power extremely energetic gamma ray bursts and hypernovae.

Black and white holes

International Nuclear Information System (INIS)

Zeldovich, Ya.; Novikov, I.; Starobinskij, A.

1978-01-01

The theory is explained of the origination of white holes as a dual phenomenon with regard to the formation of black holes. Theoretically it is possible to derive the white hole by changing the sign of time in solving the general theory of relativity equation implying the black hole. The white hole represents the amount of particles formed in the vicinity of a singularity. For a distant observer, matter composed of these particles expands and the outer boundaries of this matter approach from the inside the gravitational radius Rsub(r). At t>>Rsub(r)/c all radiation or expulsion of matter terminates. For the outside observer the white hole exists for an unlimited length of time. In fact, however, it acquires the properties of a black hole and all processes in it cease. The qualitative difference between a white hole and a black hole is in that a white hole is formed as the result of an inner quantum explosion from the singularity to the gravitational radius and not as the result of a gravitational collapse, i.e., the shrinkage of diluted matter towards the gravitational radius. (J.B.)

Black and white holes

Energy Technology Data Exchange (ETDEWEB)

Zeldovich, Ya; Novikov, I; Starobinskii, A

1978-07-01

The theory is explained of the origination of white holes as a dual phenomenon with regard to the formation of black holes. Theoretically it is possible to derive the white hole by changing the sign of time in solving the general theory of relativity equation implying the black hole. The white hole represents the amount of particles formed in the vicinity of a singularity. For a distant observer, matter composed of these particles expands and the outer boundaries of this matter approach from the inside the gravitational radius R/sub r/. At t>>R/sub r//c all radiation or expulsion of matter terminates. For the outside observer the white hole exists for an unlimited length of time. In fact, however, it acquires the properties of a black hole and all processes in it cease. The qualitative difference between a white hole and a black hole is in that a white hole is formed as the result of an inner quantum explosion from the singularity to the gravitational radius and not as the result of a gravitational collapse, i.e., the shrinkage of diluted matter towards the gravitational radius.

[The crooked nose: correction of dorsal and caudal septal deviations].

Science.gov (United States)

Foda, H M T

2010-09-01

The deviated nose represents a complex cosmetic and functional problem. Septal surgery plays a central role in the successful management of the externally deviated nose. This study included 800 patients seeking rhinoplasty to correct external nasal deviations; 71% of these suffered from variable degrees of nasal obstruction. Septal surgery was necessary in 736 (92%) patients, not only to improve breathing, but also to achieve a straight, symmetric external nose. A graduated surgical approach was adopted to allow correction of the dorsal and caudal deviations of the nasal septum without weakening its structural support to the nasal dorsum or nasal tip. The approach depended on full mobilization of deviated cartilage, followed by straightening of the cartilage and its fixation in the corrected position by using bony splinting grafts through an external rhinoplasty approach.

Effect of nalbuphine as an adjuvant on levobupivacaine induced caudal analgesia in children undergoing surgical procedures, controlled randomized double blinded

Directory of Open Access Journals (Sweden)

Riham Hussein Saleh

2016-01-01

Conclusion: Caudal epidural nalbuphine is safe in pediatric surgeries including the lower half of the body and effectively reduces postoperative pain. However it may cause early postoperative sedation, yet without respiratory depression.

Astrophysical black holes

CERN Document Server

Gorini, Vittorio; Moschella, Ugo; Treves, Aldo; Colpi, Monica

2016-01-01

Based on graduate school lectures in contemporary relativity and gravitational physics, this book gives a complete and unified picture of the present status of theoretical and observational properties of astrophysical black holes. The chapters are written by internationally recognized specialists. They cover general theoretical aspects of black hole astrophysics, the theory of accretion and ejection of gas and jets, stellar-sized black holes observed in the Milky Way, the formation and evolution of supermassive black holes in galactic centers and quasars as well as their influence on the dynamics in galactic nuclei. The final chapter addresses analytical relativity of black holes supporting theoretical understanding of the coalescence of black holes as well as being of great relevance in identifying gravitational wave signals. With its introductory chapters the book is aimed at advanced graduate and post-graduate students, but it will also be useful for specialists.

Numerical investigation of the effects of geometric parameters on transverse motion with slanted-groove micro-mixers

Energy Technology Data Exchange (ETDEWEB)

Baik, Seung Joo; Cho, Jae Yong; Choi, Se Bin; Lee, Joon Sang [School of Mechanical Engineering, Yonsei University, Seoul (Korea, Republic of)

2016-08-15

We investigated hydrodynamic phenomena inside several passive microfluidic mixers using a Lattice Boltzmann method (LBM) based on particle mesoscopic kinetic equations. Mixing processes were simulated in a Slanted grooved micro-mixer (SGM), a Staggered herringbone grooved micro-mixer (SHM), and a Bi-layered staggered herringbone grooved micro-mixer (BSHM). Then, the effects of six geometric mixer parameters (i.e., groove height to channel height ratio, groove width to groove pitch length ratio, groove pitch to groove height ratio, groove intersection angle, herringbone groove asymmetric ratio and bi-layered groove asymmetric ratio) on mixing were investigated using computed cross-flow velocity and helicity density distributions in the flow cross-section. We demonstrated that helicity density provides sufficient information to analyze micro helical motion within a micro-mixer, allowing for micro-mixer design optimization.

The Termination Level of the Dural Sac Relevant to Caudal Epidural Block in Lumbosacral Transitional Vertebrae: A Comparison between Sacralization and Lumbarization Groups.

Science.gov (United States)

Jeon, Ji Young; Jeong, Yu Mi; Lee, Sheen-Woo; Kim, Jeong Ho; Choi, Hye-Young; Ahn, Yong

2018-01-01

Lumbosacral transitional vertebrae (LSTV) are a relatively common variant and have been considered as one of the reasons for back pain. It is not unusual for clinicians to encounter patients with LSTV who require caudal epidural block (CEB) for pain management. We investigated the termination level of the dural sac (DS) and anatomical features of the lumbosacral region relevant to CEB in patients with LSTV and compared these findings between sacralization and lumbarization groups. A retrospective evaluation. A university hospital with inpatient and outpatient LSTV cases presenting low back pain. Four hundred ninety-four LSTV patients were included and categorized into sacralization (n = 201) or lumbarization groups (n = 293). Magnetic resonance imaging (MRI) of all of the LSTV patients were reviewed to determine the level of DS termination, the shortest distance between the apex of the sacral hiatus and DS, and the presence and the caudal level of sacral perineural cysts. Each lumbosacral vertebra column was divided into 3 equal portions (upper, middle, and lower thirds). The MRI findings in both of the groups were compared and analyzed. The distribution frequency of the levels of DS termination demonstrated a significant difference between the 2 groups. The mean caudal DS level in the lumbarization group was significantly lower than the sacralization group (lower third of the S2 [131 {44.7%} of 293 patients] vs. lower third of the S1 [78 {38.8%} of 201 patients]). The DS terminated at the S3 in more than 19% of the lumbarization group, whereas in only one case of the sacralization group. Although the incidence of perineural cysts was not significantly different between the 2 groups, the mean level of caudal margin of perineural cysts in the lumbarization group was significantly lower than the sacralization group (middle third of the S3 [10 {35.7%} of 28 cases] vs. middle third of the S2 [11 {44%} of 25 cases]). This study reveals several limitations including the

Black holes in binary stars

NARCIS (Netherlands)

Wijers, R.A.M.J.

1996-01-01

Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes

The stable problem of the black-hole connected region in the Schwarzschild black hole

OpenAIRE

Tian, Guihua

2005-01-01

The stability of the Schwarzschild black hole is studied. Using the Painlev\\'{e} coordinate, our region can be defined as the black-hole-connected region(r>2m, see text) of the Schwarzschild black hole or the white-hole-connected region(r>2m, see text) of the Schwarzschild black hole. We study the stable problems of the black-hole-connected region. The conclusions are: (1) in the black-hole-connected region, the initially regular perturbation fields must have real frequency or complex frequen...

Effects of ketamine and midazolam on emergence agitation after sevoflurane anaesthesia in children receiving caudal block: a randomized trial

Directory of Open Access Journals (Sweden)

Ayse Ozcan

2014-11-01

Full Text Available Background and objectives: Emergence agitation is a common postanaesthetic problem in children after sevoflurane anaesthesia. We aimed to compare the effects of ketamine and midazolam administered intravenously, before the end of surgery, for prevention of emergence agitation in children who received caudal block for pain relief under sevoflurane anaesthesia. Methods: 62 American Society of Anesthesiologists patient classification status I children, aged 2–7 years, scheduled for inguinal hernia repair, circumcision or orchidopexy were enrolled to the study. Anaesthesia was induced with sevoflurane 8% in a mixture of 50% oxygen and nitrous oxide. After achieving adequate depth of anaesthesia, a laryngeal mask was placed and then caudal block was performed with 0.75 mL kg−1, 0.25% bupivacaine. At the end of the surgery, ketamine 0.25 mg kg−1, midazolam 0.03 mg kg−1 and saline were given to ketamine, midazolam and control groups, respectively. Agitation was assessed using Paediatric Anaesthesia Emergence Delirium scale and postoperative pain was evaluated with modified Children's Hospital of Eastern Ontario Pain Scale. Results and conclusions: Modified Children's Hospital of Eastern Ontario Pain Scale scores were found higher in control group than in ketamine and midazolam groups. Paediatric Anaesthesia Emergence Delirium scores were similar between groups. Modified Children's Hospital of Eastern Ontario Pain Scale and Paediatric Anaesthesia Emergence Delirium scores showed a significant decrease by time in all groups during follow-up in postanaesthesia care unit. The present study resulted in satisfactory Paediatric Anaesthesia Emergence Delirium scores which are below 10 in all groups. As a conclusion, neither ketamine nor midazolam added to caudal block under sevoflurane anaesthesia did show further effect on emergence agitation. In addition, pain relief still seems to be the major factor in preventing emergence agitation after

Rotating black holes at future colliders. III. Determination of black hole evolution

International Nuclear Information System (INIS)

Ida, Daisuke; Oda, Kin-ya; Park, Seong Chan

2006-01-01

TeV scale gravity scenario predicts that the black hole production dominates over all other interactions above the scale and that the Large Hadron Collider will be a black hole factory. Such higher-dimensional black holes mainly decay into the standard model fields via the Hawking radiation whose spectrum can be computed from the greybody factor. Here we complete the series of our work by showing the greybody factors and the resultant spectra for the brane-localized spinor and vector field emissions for arbitrary frequencies. Combining these results with the previous works, we determine the complete radiation spectra and the subsequent time evolution of the black hole. We find that, for a typical event, well more than half a black hole mass is emitted when the hole is still highly rotating, confirming our previous claim that it is important to take into account the angular momentum of black holes

Black holes. Chapter 6

International Nuclear Information System (INIS)

Penrose, R.

1980-01-01

Conditions for the formation of a black hole are considered, and the properties of black holes. The possibility of Cygnus X-1 as a black hole is discussed. Einstein's theory of general relativity in relation to the formation of black holes is discussed. (U.K.)

Statistical black-hole thermodynamics

International Nuclear Information System (INIS)

Bekenstein, J.D.

1975-01-01

Traditional methods from statistical thermodynamics, with appropriate modifications, are used to study several problems in black-hole thermodynamics. Jaynes's maximum-uncertainty method for computing probabilities is used to show that the earlier-formulated generalized second law is respected in statistically averaged form in the process of spontaneous radiation by a Kerr black hole discovered by Hawking, and also in the case of a Schwarzschild hole immersed in a bath of black-body radiation, however cold. The generalized second law is used to motivate a maximum-entropy principle for determining the equilibrium probability distribution for a system containing a black hole. As an application we derive the distribution for the radiation in equilibrium with a Kerr hole (it is found to agree with what would be expected from Hawking's results) and the form of the associated distribution among Kerr black-hole solution states of definite mass. The same results are shown to follow from a statistical interpretation of the concept of black-hole entropy as the natural logarithm of the number of possible interior configurations that are compatible with the given exterior black-hole state. We also formulate a Jaynes-type maximum-uncertainty principle for black holes, and apply it to obtain the probability distribution among Kerr solution states for an isolated radiating Kerr hole

Black hole hair removal

International Nuclear Information System (INIS)

Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

2009-01-01

Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair - degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

Ontogeny of head and caudal fin shape of an apex marine predator: The tiger shark (Galeocerdo cuvier).

Science.gov (United States)

Fu, Amy L; Hammerschlag, Neil; Lauder, George V; Wilga, Cheryl D; Kuo, Chi-Yun; Irschick, Duncan J

2016-05-01

How morphology changes with size can have profound effects on the life history and ecology of an animal. For apex predators that can impact higher level ecosystem processes, such changes may have consequences for other species. Tiger sharks (Galeocerdo cuvier) are an apex predator in tropical seas, and, as adults, are highly migratory. However, little is known about ontogenetic changes in their body form, especially in relation to two aspects of shape that influence locomotion (caudal fin) and feeding (head shape). We captured digital images of the heads and caudal fins of live tiger sharks from Southern Florida and the Bahamas ranging in body size (hence age), and quantified shape of each using elliptical Fourier analysis. This revealed changes in the shape of the head and caudal fin of tiger sharks across ontogeny. Smaller juvenile tiger sharks show an asymmetrical tail with the dorsal (upper) lobe being substantially larger than the ventral (lower) lobe, and transition to more symmetrical tail in larger adults, although the upper lobe remains relatively larger in adults. The heads of juvenile tiger sharks are more conical, which transition to relatively broader heads over ontogeny. We interpret these changes as a result of two ecological transitions. First, adult tiger sharks can undertake extensive migrations and a more symmetrical tail could be more efficient for swimming longer distances, although we did not test this possibility. Second, adult tiger sharks expand their diet to consume larger and more diverse prey with age (turtles, mammals, and elasmobranchs), which requires substantially greater bite area and force to process. In contrast, juvenile tiger sharks consume smaller prey, such as fishes, crustaceans, and invertebrates. Our data reveal significant morphological shifts in an apex predator, which could have effects for other species that tiger sharks consume and interact with. © 2016 Wiley Periodicals, Inc.

Radiographic evaluation of caudal vena cava size in dogs

International Nuclear Information System (INIS)

Lehmkuhl, L.B.; Bonagura, J.D.; Biller, D.S.; Hartman, W.M.

1997-01-01

Dilation of the caudal vena cava (CVC) on lateral thoracic radiographs is often interpreted as suggestive of right-sided congestive heart failure, To quantitate the clinical utility of evaluating CVC size as an indicator of right-sided heart disease, we compared the ratio of the diameter of the CVC as measured on a left lateral thoracic radiograph to the descending aorta (Ao), length of the thoracic vertebra above the tracheal bifurcation (VL), and width of the right fourth rib (R4) in 35 dogs with right heart disease and 35 control dogs, Each CVC ratio(CVC/Ao, CVC/VL, CVC/R4) was statistically larger in dogs with right heart disease, Response operating characteristic curves and likelihood ratios were used to determine ratios helpful in identifying dogs with right heart disease. A CVC/Ao > 1.50, CVC/VL > 1.30, or CVC/R4 > 3.50 are strongly suggestive of a right-sided heart abnormality in a patient

Laparoscopic Radical Extended Right Hemicolectomy Using a Caudal-to-Cranial Approach.

Science.gov (United States)

Zou, Liaonan; Xiong, Wenjun; Mo, Delong; He, Yaobin; Li, Hongming; Tan, Ping; Wang, Wei; Wan, Jin

2016-08-01

Due to the emphasis of oncologic principle, a medial-to-lateral approach for laparoscopic right hemicolectomy was recommended.1 (,) 2 This approach, however, is technically challenging and involves several limitations with overweight patients, whose mesocolon may be too thick for identification of the vessel landmarks. Moreover, it is difficult for inexperienced surgeons to enter the retroperitoneum space accurately. This report describes a caudal-to-cranial approach for laparoscopic radical extended right hemicolectomy. First, a "yellow-white borderline" between the right mesostenium and retroperitoneum in the right iliac fossa is dissected as the entry for separation of the fusion fascial space between the visceral and parietal peritoneum.3 The right Toldt's fascia is dissected and expanded medial to the periphery of the superior mesenteric vein (SMV), cranial to the pancreas head, and lateral to the ascending colon. The posterior paries of ileocolic vessels (ICVs), right colic vessels (RCVs), and Henle's trunk are exposed. Second, the mesocolon between the ICV and SMV is dissected safely, and the ICV, RCV, and right gastroepiploic vessels as well as the right branch of the middle colic vessel are divided and ligated easily because of the separated retroperitoneal space. The lymph nodes along the SMV are dissected using a caudal-to-cranial approach. Third, the greater omental is dissected for full mobilization of the mesocolon containing 10 cm of normal colon distal to the lesion followed by complete mobilization of the lateral attachments of the ascending colon. In this study, 10 men and 8 women with hepatic flexure cancer underwent laparoscopic extended right hemicolectomy using a caudal-to-cranial approach. No conversion was recorded. The overall complication rate was 11.2 %, including one case of pulmonary infection and one case of urinary tract infection, both of which were cured with conservative measures. The mean age of the patients was 61.3 ± 12.7�

Brane holes

International Nuclear Information System (INIS)

Frolov, Valeri P.; Mukohyama, Shinji

2011-01-01

The aim of this paper is to demonstrate that in models with large extra dimensions under special conditions one can extract information from the interior of 4D black holes. For this purpose we study an induced geometry on a test brane in the background of a higher-dimensional static black string or a black brane. We show that, at the intersection surface of the test brane and the bulk black string or brane, the induced metric has an event horizon, so that the test brane contains a black hole. We call it a brane hole. When the test brane moves with a constant velocity V with respect to the bulk black object, it also has a brane hole, but its gravitational radius r e is greater than the size of the bulk black string or brane r 0 by the factor (1-V 2 ) -1 . We show that bulk ''photon'' emitted in the region between r 0 and r e can meet the test brane again at a point outside r e . From the point of view of observers on the test brane, the events of emission and capture of the bulk photon are connected by a spacelike curve in the induced geometry. This shows an example in which extra dimensions can be used to extract information from the interior of a lower-dimensional black object. Instead of the bulk black string or brane, one can also consider a bulk geometry without a horizon. We show that nevertheless the induced geometry on the moving test brane can include a brane hole. In such a case the extra dimensions can be used to extract information from the complete region of the brane-hole interior. We discuss thermodynamic properties of brane holes and interesting questions which arise when such an extra-dimensional channel for the information mining exists.

Ultrasound versus fluoroscopy-guided caudal epidural steroid injection for the treatment of chronic low back pain with radiculopathy: A randomised, controlled clinical trial

Directory of Open Access Journals (Sweden)

Arindam Kumar Hazra

2016-01-01

Full Text Available Background and Aims: Caudal epidural steroid administration is an effective treatment for chronic low back pain (LBP. Fluoroscopy guidance is the gold standard for pain procedures. Ultrasound guidance is recently being used in pain clinic procedures. We compared the fluoroscopy guidance and ultrasound guidance for caudal epidural steroid injection with respect to the time needed for correct placement of the needle and clinical effectiveness in patients with chronic LBP. Methods: Fifty patients with chronic LBP with radiculopathy, not responding to conventional medical management, were randomly allocated to receive injection depot methyl prednisolone (40 mg through caudal route either using ultrasound guidance (Group U, n = 25 or fluoroscopy guidance (Group F, n = 25. Pre-procedural visual analogue scale (VAS score and Oswestry Disability Index (ODI were noted. During the procedure, the time needed for correct placement of needle was observed. Adverse events, if any, were also noted. All patients were followed up for next 2 months to evaluate Visual Analogue Scale (VAS score and ODI at the 2nd week and again at the end of 1st and 2nd month. Results: The needle-placement time was less using ultrasound guidance as compared to fluoroscopy guidance (119 ± 7.66 vs. 222.28 ± 29.65 s, respectively,P< 0.001. Significant reduction in VAS score and ODI (clinical improvement was noted in the follow-up time points and comparable between the groups at all time points. Conclusion: Ultrasound guidance can be a safe alternative tool for achieving faster needle placement in caudal epidural space. Clinical effectiveness (reduction of VAS and ODI scores remains comparable between both the techniques.

Caudal anesthesia in a patient with peritonitis: Is it safe??

Directory of Open Access Journals (Sweden)

H Kako

2016-01-01

Full Text Available Neuraxial anesthesia combined with general anesthesia has become a widely accepted method of providing effective postoperative analgesia and decreasing intraoperative anesthetic needs in the pediatric population. In clinical practice, there still appears to be hesitancy for the use of a neuraxial technique (spinal or epidural in patients at risk for bacteremia or with an on-going systemic infection. However, evidence-based medicine lacks any data to support an increase in the risk of infectious complications following neuraxial anesthesia. We present two pediatric patients with intra-abdominal infectious processes who received caudal epidural blockade for postoperative operative analgesia. The use of neuraxial techniques in patients at risk for bacteremia is reviewed, evidence-based medicine regarding the risks of infection discussed, and the potential favorable effects of neuraxial blockade on the neurohumoral response to sepsis and the systemic inflammatory responses presented.

Black holes are warm

International Nuclear Information System (INIS)

Ravndal, F.

1978-01-01

Applying Einstein's theory of gravitation to black holes and their interactions with their surroundings leads to the conclusion that the sum of the surface areas of several black holes can never become less. This is shown to be analogous to entropy in thermodynamics, and the term entropy is also thus applied to black holes. Continuing, expressions are found for the temperature of a black hole and its luminosity. Thermal radiation is shown to lead to explosion of the black hole. Numerical examples are discussed involving the temperature, the mass, the luminosity and the lifetime of black mini-holes. It is pointed out that no explosions corresponding to the prediction have been observed. It is also shown that the principle of conservation of leptons and baryons is broken by hot black holes, but that this need not be a problem. The related concept of instantons is cited. It is thought that understanding of thermal radiation from black holes may be important for the development of a quantified gravitation theory. (JIW)

Hole history, rotary hole DC-3

International Nuclear Information System (INIS)

1977-10-01

Purpose of hole DC-3 was to drill into the Umtanum basalt flow using both conventional rotary and core drilling methods. The borehole is to be utilized for geophysical logging, future hydrological testing, and the future installation of a borehole laboratory for long-term pressure, seismic, and moisture migration or accumulation recording in the Umtanum basalt flow in support of the Basalt Waste Isolation Program. Hole DC-3 is located east of the 200 West barricaded area on the Hanford reservation

Evaluación de requerimientos ecológicos para el diseño de regímenes ambientales de caudales fluviales

Directory of Open Access Journals (Sweden)

Juan Manuel Diez-Hernández

2008-11-01

Full Text Available Las sociedades avanzadas medioambientalmente están reclamando progresivamente una gestión fluvial auténticamente integral, que implemente Planes de Manejo de Cuencas Hidrográficas fundamentados en el paradigma del Régimen Ambiental de Caudales (RAC. Este trabajo sugiere una metodología genérica para establecer RAC confiables, que posibiliten el aprovechamiento hídrico a un coste ecológico admisible. Adicionalmente, plantea los criterios y técnicas preferentes para la evaluación de los requerimientos ecosistémicos de caudal, los cuales componen el RAC mediante el Régimen de Caudales Ecológicos (RCE. La adaptación de estos procedimientos para los ríos de Colombia favorecerá la conservación de su valiosa biodiversidad. / The environmentally advanced societies are claiming progressively an authentically integral fluvial management, that implements Watershed Management Programs based on the paradigm of the Environmental Flows Regime (EFR. This work suggests a generic methodology for the reliable EFR setting, that facilitate the water use with an environmental acceptable cost. Additionally, it outlines the approaches and outstanding techniques for the evaluation of instream flow requirements, which constitute the EFR by means of the Instream Flow Regime (IFR. The adaptation of these approaches to the Colombian rivers will contribute to the conservation of their valuable biodiversity.

Quantum aspects of black holes

CERN Document Server

2015-01-01

Beginning with an overview of the theory of black holes by the editor, this book presents a collection of ten chapters by leading physicists dealing with the variety of quantum mechanical and quantum gravitational effects pertinent to black holes. The contributions address topics such as Hawking radiation, the thermodynamics of black holes, the information paradox and firewalls, Monsters, primordial black holes, self-gravitating Bose-Einstein condensates, the formation of small black holes in high energetic collisions of particles, minimal length effects in black holes and small black holes at the Large Hadron Collider. Viewed as a whole the collection provides stimulating reading for researchers and graduate students seeking a summary of the quantum features of black holes.

Black holes and beyond

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-02-01

Belief in the existence of black holes is the ultimate act of faith for a physicist. First suggested by the English clergyman John Michell in the year 1784, the gravitational pull of a black hole is so strong that nothing - not even light - can escape. Gravity might be the weakest of the fundamental forces but black-hole physics is not for the faint-hearted. Black holes present obvious problems for would-be observers because they cannot, by definition, be seen with conventional telescopes - although before the end of the decade gravitational-wave detectors should be able to study collisions between black holes. Until then astronomers can only infer the existence of a black hole from its gravitational influence on other matter, or from the X-rays emitted by gas and dust as they are dragged into the black hole. However, once this material passes through the 'event horizon' that surrounds the black hole, we will never see it again - not even with X-ray specs. Despite these observational problems, most physicists and astronomers believe that black holes do exist. Small black holes a few kilometres across are thought to form when stars weighing more than about two solar masses collapse under the weight of their own gravity, while supermassive black holes weighing millions of solar masses appear to be present at the centre of most galaxies. Moreover, some brave physicists have proposed ways to make black holes - or at least event horizons - in the laboratory. The basic idea behind these 'artificial black holes' is not to compress a large amount of mass into a small volume, but to reduce the speed of light in a moving medium to less than the speed of the medium and so create an event horizon. The parallels with real black holes are not exact but the experiments could shed new light on a variety of phenomena. The first challenge, however, is to get money for the research. One year on from a high-profile meeting on artificial black holes in London, for

Desarrollo osteológico de la columna vertebral y del complejo caudal de larvas de Lutjanus guttatus (Perciformes: Lutjanidae en condiciones de cultivo

Directory of Open Access Journals (Sweden)

Luz Estela Rodríguez-Ibarra

2015-03-01

Full Text Available El pargo flamenco (Lutjanus guttatus es una especie de importancia comercial en México con un gran potencial para su cultivo. El estudio osteológico en estadios tempranos de esta especie bajo condiciones controladas, es una herramienta importante para el conocimiento de su estructura ósea normal y poder detectar las malformaciones que se puedan presentar. El objetivo del presente trabajo se realizó para conocer y describir el desarrollo osteológico normal de la columna vertebral y el complejo caudal de 540 larvas de 2.1 a 17.5mm de longitud total (LT bajo condiciones de cultivo a 28°C, 5.74mg/L de oxígeno y 32.2UPS de salinidad. Diariamente se tomó una muestra de 15 organismos desde el día uno hasta el 36 después de la eclosión (DDE y se procesaron con las técnicas de clareado y tinción de cartílago (azul aciano y hueso (rojo alizarina para llevar a cabo la descripción de las estructuras. La columna vertebral se divide en región abdominal con diez vértebras y región caudal compuesta por 14 vértebras incluido el urostilo. El desarrollo del esqueleto axial inicia con la formación de los arcos neurales y hemales a los 3.8mm de LT. A los 4.1mm de LT empieza la formación de los hipurales y parahipural que son elementos caudales. Entre los 5.3 y 5.8mm de LT se observó en pre-flexión y flexión del notocordio y la formación de todos los hipurales. La osificación de las vértebras en la región abdominal y en algunos arcos neurales inició a los 9.5mm de LT. A los 10.2mm de LT se osificó la región caudal y todos los arcos neurales y hemales. A los 11.2mm LT se osificaron todas las vértebras abdominales con sus respectivos arcos neurales y los parapófisis, mientras que los elementos del esqueleto caudal que se osificaron fueron los hipurales, parahipurales y las espinas hemales modificadas. A los 15.5mm de LT se osificaron los radios de la aleta caudal y 12 espinas neurales y 3 hemales. El proceso de osificación de las

Investigation of Spiral and Sweeping Holes

Science.gov (United States)

Thurman, Douglas; Poinsatte, Philip; Ameri, Ali; Culley, Dennis; Raghu, Surya; Shyam, Vikram

2015-01-01

Surface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and Square holes. A patent-pending spiral hole design showed the highest potential of the non-diffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing rations of 1.0, 1.5, 2.0, and 2.5 at a density ration of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS.

Sirenomelia and severe caudal regression syndrome.

Science.gov (United States)

Seidahmed, Mohammed Z; Abdelbasit, Omer B; Alhussein, Khalid A; Miqdad, Abeer M; Khalil, Mohammed I; Salih, Mustafa A

2014-12-01

To describe cases of sirenomelia and severe caudal regression syndrome (CRS), to report the prevalence of sirenomelia, and compare our findings with the literature. Retrospective data was retrieved from the medical records of infants with the diagnosis of sirenomelia and CRS and their mothers from 1989 to 2010 (22 years) at the Security Forces Hospital, Riyadh, Saudi Arabia. A perinatologist, neonatologist, pediatric neurologist, and radiologist ascertained the diagnoses. The cases were identified as part of a study of neural tube defects during that period. A literature search was conducted using MEDLINE. During the 22-year study period, the total number of deliveries was 124,933 out of whom, 4 patients with sirenomelia, and 2 patients with severe forms of CRS were identified. All the patients with sirenomelia had single umbilical artery, and none were the infant of a diabetic mother. One patient was a twin, and another was one of triplets. The 2 patients with CRS were sisters, their mother suffered from type II diabetes mellitus and morbid obesity on insulin, and neither of them had a single umbilical artery. Other associated anomalies with sirenomelia included an absent radius, thumb, and index finger in one patient, Potter's syndrome, abnormal ribs, microphthalmia, congenital heart disease, hypoplastic lungs, and diaphragmatic hernia. The prevalence of sirenomelia (3.2 per 100,000) is high compared with the international prevalence of one per 100,000. Both cases of CRS were infants of type II diabetic mother with poor control, supporting the strong correlation of CRS and maternal diabetes.

Black Hole Area Quantization rule from Black Hole Mass Fluctuations

OpenAIRE

Schiffer, Marcelo

2016-01-01

We calculate the black hole mass distribution function that follows from the random emission of quanta by Hawking radiation and with this function we calculate the black hole mass fluctuation. From a complete different perspective we regard the black hole as quantum mechanical system with a quantized event horizon area and transition probabilities among the various energy levels and then calculate the mass dispersion. It turns out that there is a perfect agreement between the statistical and ...

Slantingly cross loading sample system enables simultaneous performance of separation and mixture to detect molecular interactions on thin-layer chromatography.

Science.gov (United States)

Shimizu-Yumoto, Hiroko; Hayashi, Nobuyuki; Ichimura, Kazuo; Nakayama, Masayoshi

2012-07-06

Anthocyanins are major flower pigments that can be affected by copigments, colorless compounds that can modify anthocyanin coloration to more intense and bluer. Thin-layer chromatography (TLC) is an available technique to separate and analyze anthocyanins and copigments. To easily and comprehensively detect copigments, we added function of mixture of compounds to TLC; by slantingly cross loading samples on TLC, compounds are symmetrically developed at various angle lines from the upper origin to individual R(f) values and cross each other in an orderly fashion, where mixture is simultaneously performed with separation. Occurrence of copigments can be detected as a coloration change on the developed line of anthocyanin. Pink sweet pea (Lathyrus odoratus L.) petals were analyzed by the cross-TLC and a more intense spot and a paler spot on the anthocyanin line were detected. As each spot overlapped with an ultraviolet absorbance line, each of these ultraviolet absorption compounds was purified and identified as kaempferol 3-rhamnoside and 2-cyanoethyl-isoxazolin-5-one, respectively. Whereas kaempferol 3-rhamnoside is a flavonoid and had a general copigment effect of more intense and bluer coloration change, 2-cyanoethyl-isoxazolin-5-one is a compound whose structure is outside of conventional categories of copigments and had a novel effect to change anthocyanin coloration paler while maintaining color tone. We determined that the search for copigments should be carried out without pre-existing prediction of structures and effects. We have shown that slantingly cross loading samples system on plate-type chromatography is an effective technique for such comprehensive analysis of molecular interaction. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Monopole Black Hole Skyrmions

OpenAIRE

Moss, Ian G; Shiiki, N; Winstanley, E

2000-01-01

Charged black hole solutions with pion hair are discussed. These can be\\ud used to study monopole black hole catalysis of proton decay.\\ud There also exist\\ud multi-black hole skyrmion solutions with BPS monopole behaviour.

Caudal léxico en alumnos universitarios : Implicancias para la interacción textual

OpenAIRE

Piatti, Vanesa; Fernicola, Alfredo; Melillo, Oscar Roberto; Peralta, Diego

2011-01-01

En este trabajo se comunican los resultados preliminares de una investigación en curso. Específicamente se refiere a los resultados encontrados en pruebas de que examinan el caudal léxico, por el interés de sus relaciones con la interacción textual. En razón de ello en la elaboración de esta comunicación se ha tenido particularmente en cuenta el modelo de comprensión lectora proporcionado por Kintsch y Rawson (2005) sobre los diferentes niveles de procesamiento cuando se lee. Los autores d...

Skyrmion black hole hair: Conservation of baryon number by black holes and observable manifestations

Energy Technology Data Exchange (ETDEWEB)

Dvali, Gia [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, 80333 München (Germany); Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, 80805 München (Germany); Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Gußmann, Alexander, E-mail: alexander.gussmann@physik.uni-muenchen.de [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, 80333 München (Germany)

2016-12-15

We show that the existence of black holes with classical skyrmion hair invalidates standard proofs that global charges, such as the baryon number, cannot be conserved by a black hole. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. We then perform a refined Gedankenexperiment by incorporating the new knowledge and show that no contradiction with conservation of baryon number takes place at any stage of black hole evolution. Our analysis also indicates no conflict between semi-classical black holes and the existence of baryonic gauge interaction arbitrarily-weaker than gravity. Next, we study classical cross sections of a minimally-coupled massless probe scalar field scattered by a skyrmion black hole. We investigate how the skyrmion hair manifests itself by comparing this cross section with the analogous cross section caused by a Schwarzschild black hole which has the same ADM mass as the skyrmion black hole. Here we find an order-one difference in the positions of the characteristic peaks in the cross sections. The peaks are shifted to smaller scattering angles when the skyrmion hair is present. This comes from the fact that the skyrmion hair changes the near horizon geometry of the black hole when compared to a Schwarzschild black hole with same ADM mass. We keep the study of this second aspect general so that the qualitative results which we obtain can also be applied to black holes with classical hair of different kind.

Entropy of quasiblack holes

International Nuclear Information System (INIS)

Lemos, Jose P. S.; Zaslavskii, Oleg B.

2010-01-01

We trace the origin of the black hole entropy S, replacing a black hole by a quasiblack hole. Let the boundary of a static body approach its own gravitational radius, in such a way that a quasihorizon forms. We show that if the body is thermal with the temperature taking the Hawking value at the quasihorizon limit, it follows, in the nonextremal case, from the first law of thermodynamics that the entropy approaches the Bekenstein-Hawking value S=A/4. In this setup, the key role is played by the surface stresses on the quasihorizon and one finds that the entropy comes from the quasihorizon surface. Any distribution of matter inside the surface leads to the same universal value for the entropy in the quasihorizon limit. This can be of some help in the understanding of black hole entropy. Other similarities between black holes and quasiblack holes such as the mass formulas for both objects had been found previously. We also discuss the entropy for extremal quasiblack holes, a more subtle issue.

Black holes without firewalls

Science.gov (United States)

Larjo, Klaus; Lowe, David A.; Thorlacius, Larus

2013-05-01

The postulates of black hole complementarity do not imply a firewall for infalling observers at a black hole horizon. The dynamics of the stretched horizon, that scrambles and reemits information, determines whether infalling observers experience anything out of the ordinary when entering a large black hole. In particular, there is no firewall if the stretched horizon degrees of freedom retain information for a time of the order of the black hole scrambling time.

The effect of particle-hole interaction on the XPS core-hole spectrum

International Nuclear Information System (INIS)

Ohno, Masahide; Sjoegren, Lennart

2004-01-01

How the effective particle-hole interaction energy, U, or the polarization effect on a secondary electron in a final two-hole one-particle (2h1p) state created by the Coster-Kronig (CK) transition can solely affect the density of the CK particle states and consequently the core-hole spectral function, is discussed. The X-ray photoelectron spectroscopy (XPS) core-hole spectrum is predominantly governed by the unperturbed initial core-hole energy relative to the zero-point energy. At the latter energy, the real part of the initial core-hole self-energy becomes zero (no relaxation energy shift) and the imaginary part (the lifetime broadening) approximately maximizes. The zero-point energy relative to the double-ionization threshold energy is governed by the ratio of U relative to the bandwidth of the CK continuum. As an example, we study the 5p XPS spectra of atomic Ra (Z=88), Th (Z=90) and U (Z=92). The spectra are interpreted in terms of the change in the unperturbed initial core-hole energy relative to the zero-point energy. We explain why in general an ab initio atomic many-body calculation can provide an overall good description of solid-state spectra predominantly governed by the atomic-like localized core-hole dynamics. We explain this in terms of the change from free atom to metal in both U and the zero-point energy (self-energy)

Over spinning a black hole?

Energy Technology Data Exchange (ETDEWEB)

Bouhmadi-Lopez, Mariam; Cardoso, Vitor; Nerozzi, Andrea; Rocha, Jorge V, E-mail: mariam.bouhmadi@ist.utl.pt, E-mail: vitor.cardoso@ist.utl.pt, E-mail: andrea.nerozzi@ist.utl.pt, E-mail: jorge.v.rocha@ist.utl.pt [CENTRA, Department de Fisica, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049 Lisboa (Portugal)

2011-09-22

A possible process to destroy a black hole consists on throwing point particles with sufficiently large angular momentum into the black hole. In the case of Kerr black holes, it was shown by Wald that particles with dangerously large angular momentum are simply not captured by the hole, and thus the event horizon is not destroyed. Here we reconsider this gedanken experiment for black holes in higher dimensions. We show that this particular way of destroying a black hole does not succeed and that Cosmic Censorship is preserved.

Parametric study of the swimming performance of a fish robot propelled by a flexible caudal fin

Energy Technology Data Exchange (ETDEWEB)

Low, K H; Chong, C W, E-mail: mkhlow@ntu.edu.s, E-mail: ch0018ee@ntu.edu.s [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

2010-12-15

In this paper, we aim to study the swimming performance of fish robots by using a statistical approach. A fish robot employing a carangiform swimming mode had been used as an experimental platform for the performance study. The experiments conducted aim to investigate the effect of various design parameters on the thrust capability of the fish robot with a flexible caudal fin. The controllable parameters associated with the fin include frequency, amplitude of oscillation, aspect ratio and the rigidity of the caudal fin. The significance of these parameters was determined in the first set of experiments by using a statistical approach. A more detailed parametric experimental study was then conducted with only those significant parameters. As a result, the parametric study could be completed with a reduced number of experiments and time spent. With the obtained experimental result, we were able to understand the relationship between various parameters and a possible adjustment of parameters to obtain a higher thrust. The proposed statistical method for experimentation provides an objective and thorough analysis of the effects of individual or combinations of parameters on the swimming performance. Such an efficient experimental design helps to optimize the process and determine factors that influence variability.

Parametric study of the swimming performance of a fish robot propelled by a flexible caudal fin.

Science.gov (United States)

Low, K H; Chong, C W

2010-12-01

In this paper, we aim to study the swimming performance of fish robots by using a statistical approach. A fish robot employing a carangiform swimming mode had been used as an experimental platform for the performance study. The experiments conducted aim to investigate the effect of various design parameters on the thrust capability of the fish robot with a flexible caudal fin. The controllable parameters associated with the fin include frequency, amplitude of oscillation, aspect ratio and the rigidity of the caudal fin. The significance of these parameters was determined in the first set of experiments by using a statistical approach. A more detailed parametric experimental study was then conducted with only those significant parameters. As a result, the parametric study could be completed with a reduced number of experiments and time spent. With the obtained experimental result, we were able to understand the relationship between various parameters and a possible adjustment of parameters to obtain a higher thrust. The proposed statistical method for experimentation provides an objective and thorough analysis of the effects of individual or combinations of parameters on the swimming performance. Such an efficient experimental design helps to optimize the process and determine factors that influence variability.

Parametric study of the swimming performance of a fish robot propelled by a flexible caudal fin

International Nuclear Information System (INIS)

Low, K H; Chong, C W

2010-01-01

In this paper, we aim to study the swimming performance of fish robots by using a statistical approach. A fish robot employing a carangiform swimming mode had been used as an experimental platform for the performance study. The experiments conducted aim to investigate the effect of various design parameters on the thrust capability of the fish robot with a flexible caudal fin. The controllable parameters associated with the fin include frequency, amplitude of oscillation, aspect ratio and the rigidity of the caudal fin. The significance of these parameters was determined in the first set of experiments by using a statistical approach. A more detailed parametric experimental study was then conducted with only those significant parameters. As a result, the parametric study could be completed with a reduced number of experiments and time spent. With the obtained experimental result, we were able to understand the relationship between various parameters and a possible adjustment of parameters to obtain a higher thrust. The proposed statistical method for experimentation provides an objective and thorough analysis of the effects of individual or combinations of parameters on the swimming performance. Such an efficient experimental design helps to optimize the process and determine factors that influence variability.

Indirect caudal lymphography using a new water-soluble contrast agent - animal experimental studies in pigs

International Nuclear Information System (INIS)

Apitzsch, D.E.; Kroll, H.U.; Zuehlke, H.V.

1981-01-01

Animal experiments on caudal lymphography in pigs are presented, using a new water-soluble contrast medium which is renally excreted. Indirect cutaneous administration renders possible the radiological visualization of the entire lymphatic drainage system of the lower limb, the retro-peritoneal space and the thoracic duct. Visualization of the lymphatic system is rapid, homogeneous and can be repeated as often as desired. The quality of the lymphogram is as good as that obtained by the current methods in common use. (orig.)

Accreting Black Holes

OpenAIRE

Begelman, Mitchell C.

2014-01-01

I outline the theory of accretion onto black holes, and its application to observed phenomena such as X-ray binaries, active galactic nuclei, tidal disruption events, and gamma-ray bursts. The dynamics as well as radiative signatures of black hole accretion depend on interactions between the relatively simple black-hole spacetime and complex radiation, plasma and magnetohydrodynamical processes in the surrounding gas. I will show how transient accretion processes could provide clues to these ...

Naked black holes

International Nuclear Information System (INIS)

Horowitz, G.T.; Ross, S.F.

1997-01-01

It is shown that there are large static black holes for which all curvature invariants are small near the event horizon, yet any object which falls in experiences enormous tidal forces outside the horizon. These black holes are charged and near extremality, and exist in a wide class of theories including string theory. The implications for cosmic censorship and the black hole information puzzle are discussed. copyright 1997 The American Physical Society

Ballistic hole magnetic microscopy

NARCIS (Netherlands)

Haq, E.; Banerjee, T.; Siekman, M.H.; Lodder, J.C.; Jansen, R.

2005-01-01

A technique to study nanoscale spin transport of holes is presented: ballistic hole magnetic microscopy. The tip of a scanning tunneling microscope is used to inject hot electrons into a ferromagnetic heterostructure, where inelastic decay creates a distribution of electron-hole pairs.

Effects of simulated microgravity on circadian rhythm of caudal arterial pressure and heart rate in rats and their underlying mechanism

Directory of Open Access Journals (Sweden)

Li CHEN

2016-04-01

Full Text Available Objective 　To explore the effects of simulated microgravity on the circadian rhythm of rats' caudal arterial pressure and heart rate, and their underlying mechanism. Methods 　Eighteen male SD rats (aged 8 weeks were randomly assigned to control (CON and tail suspension (SUS group (9 each. Rats with tail suspension for 28 days were adopted as the animal model to simulate microgravity. Caudal arterial pressure and heart rate of rats were measured every 3 hours. The circadian difference of abdominal aorta contraction was measured by aortic ring test. Western blotting was performed to determine and compare the protein expression level of clock genes such as Per2 (Period2, Bmal1 (Aryl hydrocarbon receptor nuclear translocatorlike and dbp (D element binding protein in suprachiasmatic nucleus (SCN and abdominal aorta of rats in CON and SUS group at different time points. Results 　Compared with CON group, the caudal arterial pressure, both systolic and diastolic pressure, decreased significantly and the diurnal variability disappeared, meanwhile the heart rate increased obviously and also the diurnal variability disappeared in rats of SUS group. Compared with CON group, the contraction reactivity of abdominal aorta decreased with disappearence of the diurnal variability, and also the clock genes expression in SCN and abdominal aorta showed no diurnal variability in rats of SUS group. Conclusion 　Simulated microgravity may lead to circadian rhythm disorders in rats' cardiovascular system, which may be associated with the changes of the clock genes expression. DOI: 10.11855/j.issn.0577-7402.2016.04.06

Black-hole driven winds

International Nuclear Information System (INIS)

Punsly, B.M.

1988-01-01

This dissertation is a study of the physical mechanism that allows a large scale magnetic field to torque a rapidly rotating, supermassive black hole. This is an interesting problem as it has been conjectured that rapidly rotating black holes are the central engines that power the observed extragalactic double radio sources. Axisymmetric solutions of the curved space-time version of Maxwell's equations in the vacuum do not torque black holes. Plasma must be introduced for the hole to mechanically couple to the field. The dynamical aspect of rotating black holes that couples the magnetic field to the hole is the following. A rotating black hole forces the external geometry of space-time to rotate (the dragging of inertial frames). Inside of the stationary limit surface, the ergosphere, all physical particle trajectories must appear to rotate in the same direction as the black hole as viewed by the stationary observers at asymptotic infinity. In the text, it is demonstrated how plasma that is created on field lines that thread both the ergosphere and the equatorial plane will be pulled by gravity toward the equator. By the aforementioned properties of the ergosphere, the disk must rotate. Consequently, the disk acts like a unipolar generator. It drives a global current system that supports the toroidal magnetic field in an outgoing, magnetically dominated wind. This wind carries energy (mainly in the form of Poynting flux) and angular momentum towards infinity. The spin down of the black hole is the ultimate source of this energy and angular momentum flux

Prediction of water flows in Colorado River, Argentina Predicción de caudales en río Colorado, Argentina

Directory of Open Access Journals (Sweden)

Jorge O Pierini

2012-11-01

Full Text Available The identification of suitable models for predicting daily water flow is important for planning and management of water storage in reservoirs of Argentina. Long-term prediction of water flow is crucial for regulating reservoirs and hydroelectric plants, for assessing environmental protection and sustainable development, for guaranteeing correct operation of public water supply in cities like Catriel, 25 de Mayo, Colorado River and potentially also Bahía Blanca. In this paper, we analyze in Buta Ranquil flow time series upstream reservoir and hydroelectric plant in order to model and predict daily fluctuations. We compare results obtained by using a three-layer artificial neural network (ANN, and an autoregressive (AR model, using 18 years of data, of which the last 3 years are used for model validation by means of the root mean square error (RMSE, and measure of certainty (Skill. Our results point out to the better performance to predict daily water flow or refill them of the ANN model performance respect to the AR model.La identificación de modelos adecuados para predecir caudales diarios es importante para la planificación y la gestión de almacenamiento de agua en los embalses de la Argentina. La predicción a largo plazo del caudal es crucial para la regulación de los embalses y centrales hidroeléctricas, evaluar la protección del medio ambiente y el desarrollo sostenible, garantizar el correcto funcionamiento del abastecimiento público de agua en ciudades como Catriel, 25 de Mayo, río Colorado y también, eventualmente, en Bahía Blanca. En este trabajo, se analizan series de tiempo de caudales de agua, arriba del embalse y de la planta hidroeléctrica en Buta Ranquil, para modelar y predecir las fluctuaciones diarias. Se comparan los resultados obtenidos mediante el uso de una red neuronal artificial (ANN de tres capas y un modelo autoregresivo (AR, con 18 anos de datos, cuyos últimos 3 anos se utilizan para la validación del

Black holes are hot

International Nuclear Information System (INIS)

Gibbons, G.

1976-01-01

Recent work, which has been investigating the use of the concept of entropy with respect to gravitating systems, black holes and the universe as a whole, is discussed. The resulting theory of black holes assigns a finite temperature to them -about 10 -7 K for ordinary black holes of stellar mass -which is in complete agreement with thermodynamical concepts. It is also shown that black holes must continuously emit particles just like ordinary bodies which have a certain temperature. (U.K.)

Intermediate-Mass Black Holes

Science.gov (United States)

Miller, M. Coleman; Colbert, E. J. M.

2004-01-01

The mathematical simplicity of black holes, combined with their links to some of the most energetic events in the universe, means that black holes are key objects for fundamental physics and astrophysics. Until recently, it was generally believed that black holes in nature appear in two broad mass ranges: stellar-mass (M~3 20 M⊙), which are produced by the core collapse of massive stars, and supermassive (M~106 1010 M⊙), which are found in the centers of galaxies and are produced by a still uncertain combination of processes. In the last few years, however, evidence has accumulated for an intermediate-mass class of black holes, with M~102 104 M⊙. If such objects exist they have important implications for the dynamics of stellar clusters, the formation of supermassive black holes, and the production and detection of gravitational waves. We review the evidence for intermediate-mass black holes and discuss future observational and theoretical work that will help clarify numerous outstanding questions about these objects.

Non-pumping reactive wells filled with mixing nano and micro zero-valent iron for nitrate removal from groundwater: Vertical, horizontal, and slanted wells

Science.gov (United States)

Hosseini, Seiyed Mossa; Tosco, Tiziana; Ataie-Ashtiani, Behzad; Simmons, Craig T.

2018-03-01

Non-pumping reactive wells (NPRWs) filled by zero-valent iron (ZVI) can be utilized for the remediation of groundwater contamination of deep aquifers. The efficiency of NPRWs mainly depends on the hydraulic contact time (HCT) of the pollutant with the reactive materials, the extent of the well capture zone (Wcz), and the relative hydraulic conductivity of aquifer and reactive material (Kr). We investigated nitrate removal from groundwater using NPRWs filled by ZVI (in nano and micro scales) and examined the effect of NPRWs orientations (i.e. vertical, slanted, and horizontal) on HCT and Wcz. The dependence of HCT on Wcz for different Kr values was derived theoretically for a homogeneous and isotropic aquifer, and verified using particle tracking simulations performed using the semi-analytical particle tracking and pathlines model (PMPATH). Nine batch experiments were then performed to investigate the impact of mixed nano-ZVI, NZVI (0 to 2 g l-1) and micro-ZVI, MZVI (0 to 4 g l-1) on the nitrate removal rate (with initial NO3-=132 mg l-1). The NPRWs system was tested in a bench-scale sand medium (60 cm length × 40 cm width × 25 cm height) for three orientations of NPRWs (vertical, horizontal, and slanted with inclination angle of 45°). A mixture of nano/micro ZVI, was used, applying constant conditions of pore water velocity (0.024 mm s-1) and initial nitrate concentration (128 mg l-1) for five pore volumes. The results of the batch tests showed that mixing nano and micro Fe0 outperforms these individual materials in nitrate removal rates. The final products of nitrate degradation in both batch and bench-scale experiments were NO2-, NH4+, and N2(gas). The results of sand-box experiments indicated that the slanted NPRWs have a higher nitrate reduction rate (57%) in comparison with vertical (38%) and horizontal (41%) configurations. The results also demonstrated that three factors have pivotal roles in expected HCT and Wcz, namely the contrast between the hydraulic

Slanted n-ZnO/p-GaN nanorod arrays light-emitting diodes grown by oblique-angle deposition

Directory of Open Access Journals (Sweden)

Ya-Ju Lee

2014-05-01

Full Text Available High-efficient ZnO-based nanorod array light-emitting diodes (LEDs were grown by an oblique-angle deposition scheme. Due to the shadowing effect, the inclined ZnO vapor-flow was selectively deposited on the tip surfaces of pre-fabricated p-GaN nanorod arrays, resulting in the formation of nanosized heterojunctions. The LED architecture composed of the slanted n-ZnO film on p-GaN nanorod arrays exhibits a well-behaving current rectification of junction diode with low turn-on voltage of 4.7 V, and stably emits bluish-white luminescence with dominant peak of 390 nm under the operation of forward injection currents. In general, as the device fabrication does not involve passivation of using a polymer or sophisticated material growth techniques, the revealed scheme might be readily applied on other kinds of nanoscale optoelectronic devices.

Analgesia pós-operatória em correção cirúrgica de pé torto congênito: comparação entre bloqueio nervoso periférico e bloqueio peridural caudal Analgesia postoperatoria en corrección quirúrgica de pie jorobado congénito: comparación entre bloqueo nervioso periférico y bloqueo epidural caudal Postoperative analgesia for the surgical correction of congenital clubfoot: comparison between peripheral nerve block and caudal epidural block

Directory of Open Access Journals (Sweden)

Monica Rossi Rodrigues

2009-12-01

Full Text Available JUSTIFICATIVA E OBJETIVOS: O procedimento de correção de pé torto congênito (PTC cursa com dor pós-operatória intensa. A técnica mais utilizada em crianças é a peridural caudal associada à anestesia geral. Tem como limitação a curta duração da analgesia pós-operatória. Os bloqueios de nervos periféricos têm sido apontados como procedimentos com baixa incidência de complicações e tempo prolongado de analgesia. O objetivo do estudo foi comparar o tempo de analgesia dos bloqueios nervosos periféricos e bloqueio caudal e o consumo de morfina nas primeiras 24 horas após a correção de PTC em crianças. MÉTODO: Estudo randômico, encoberto, em crianças submetidas à intervenção cirúrgica para liberação póstero-medial de PTC, alocadas em 4 grupos conforme a técnica anestésica: Caudal (ACa; Bloqueios isquiático e femoral (IF; Bloqueios isquiático e safeno (IS; Bloqueio isquiático e anestesia local (IL, associados à anestesia geral. Nas primeiras 24 horas os pacientes receberam dipirona e paracetamol via oral e foram avaliados por anestesiologista que desconhecia a técnica empregada. Conforme escores da escala CHIPPS (Children's and infants postoperative pain scale era administrada morfina via oral (0,19 mg.kg-1 por dia. RESULTADOS: Foram estudadas 118 crianças distribuídas nos grupos ACa (30, IF (32, IS (28 IL (28. O tempo médio entre o bloqueio e a primeira dose de morfina foi 6,16 horas no grupo ACa, 7,05 horas no IF, 7,58 horas no IS e 8,18 horas no IL. O consumo de morfina foi 0,3 mg.kg-1 por dia nos quatro grupos. Não houve diferença significativa entre os grupos. CONCLUSÕES: Os bloqueios nervosos periféricos não promoveram maior tempo de analgesia, tampouco redução no consumo de morfina nas primeiras 24 horas em crianças submetidas à correção de PTC quando comparados ao bloqueio peridural caudal.JUSTIFICATIVA Y OBJETIVOS: El procedimiento de corrección de pie jorobado congénito (PJC, debuta

Caudal epidural injections for lumbar prolapsed inter vertebral disc: assessment with urdu version of oswestry disability index

International Nuclear Information System (INIS)

Pasha, I.F.; Qureshi, M.A.; Farooq, M.

2014-01-01

Background/Aims: Oswestry Disability index is an established tool for assessment of Spinal Disability. It has been translated into many languages and but not to Urdu. The aim of this prospective observational study was translation, application and validation of Urdu version of the Oswestry Disability Index (Urdu ODI) for our specific cultural background. Methods: Urdu version of ODI was developed and applied for outcome assessment in 50 patients, suffering from lumbar prolapsed inter vertebral discs and treated with caudal epidural steroid injection. All patients having mechanical low backache with radiculopathy and single level disc prolapse at L-4-5 or L5- S 1 on Magnetic Resonance Imaging (MRI) were included in the study. Single Steroid Injection with local anesthetic was injected into sacral caudal epidural space through sacral hiatus. A Performa was made for each patient and records were kept in a custom built Microsoft access database. Outcome was assessed using Urdu ODI and validation by comparing with Numeric rating Scale 0-10 at each visit. Results: Fifty patients received caudal epidural injections, 23 (46%) were male and 27 (54%) were female. The mean age was 34 years, with the range being 21-55. Low mechanical backache with right sided radiculopathy was in 29 (58%) and left sided in 21 (42%) patients. The commonest involved disc was L4-S in 28 (56%) and L5-S1 in 22 (44%) patients Pain was assessed with Numeric Rating Scale (NRS) of ten points. This was mean 7.35, range 9-6 at presentation and mean improvement was 4.15 with range 5-3 at fist week, 3.80 with range 5-2 at first month and 3.05 with range 4-1 after six months. Functional disability assessment was done using Urdu ODI. The mean Urdu ODI at the time of presentation was 66.23% with range 81%-48%. The mean functional status was found to be 38.64% with range 26%-45% at the end of the first week, 43.65% with range 31%-48% after one month and 44.85% with range 28%-48% after six months. So there was

Black hole multiplicity at particle colliders (Do black holes radiate mainly on the brane?)

International Nuclear Information System (INIS)

Cavaglia, Marco

2003-01-01

If gravity becomes strong at the TeV scale, we may have the chance to produce black holes at particle colliders. In this Letter we revisit some phenomenological signatures of black hole production in TeV-gravity theories. We show that the bulk-to-brane ratio of black hole energy loss during the Hawking evaporation phase depends crucially on the black hole greybody factors and on the particle degrees of freedom. Since the greybody factors have not yet been calculated in the literature, and the particle content at trans-Planckian energies is not known, it is premature to claim that the black hole emits mainly on the brane. We also revisit the decay time and the multiplicity of the decay products of black hole evaporation. We give general formulae for black hole decay time and multiplicity. We find that the number of particles produced during the evaporation phase may be significantly lower than the average multiplicity which has been used in the past literature

String-Corrected Black Holes

Energy Technology Data Exchange (ETDEWEB)

Hubeny, V.

2005-01-12

We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect--the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive. The magnitude of this effect is related to the size of the compactification manifold.

Video studies of passage by Anopheles gambiae mosquitoes through holes in a simulated bed net: effects of hole size, hole orientation and net environment.

Science.gov (United States)

Sutcliffe, James; Colborn, Kathryn L

2015-05-13

Holes in netting provide potential routes for mosquitoes to enter ITNs. Despite this, there is little information on how mosquitoes respond to holes in bed nets and how their responses are affected by hole size, shape and orientation or by ambient conditions around the net. Female Anopheles gambiae (G3) were recorded in a simulated bed net consisting of two sizes of untreated netting-covered behavioural arenas placed above and beside (to simulate the bed net roof and sides respectively) the experimenter who was a source of host cues from 'inside' the net. A round hole of 9 mm or 13 mm diameter was cut into the centre of the netting of each arena. Videos of unfed female mosquitoes in arenas were analysed for time spent flying, walking and standing still and for exit through the hole. The effects of the experimenter on temperature and relative humidity around the simulated net were also measured. Mosquitoes were significantly more active in overhead arenas than in arenas to the side. Hole passage was significantly more likely in smaller arenas than larger ones and for larger holes than smaller ones. In arenas to the side, hole passage rate through small holes was about 50% less likely than what could be explained by area alone. Passage rate through holes in overhead arenas was consistent with hole area. Temperature in arenas did not strongly reflect the experimenter's presence in the simulated net. Relative humidity and absolute humidity in overhead arenas, but not in arenas to the side, were immediately affected by experimenter presence. Higher levels of activity in overhead arenas than in arenas to the side were likely due to the rising heat and humidity plume from the experimenter. Lower than expected passage rates through smaller vertically oriented holes may have been be due to an edge effect that does not apply to horizontally oriented holes. Results suggest that current methods of assessing the importance of physical damage to ITNs may not accurately reflect

Structural differences between glycosylated, disulfide-linked heterodimeric Knob-into-Hole Fc fragment and its homodimeric Knob-Knob and Hole-Hole side products.

Science.gov (United States)

Kuglstatter, A; Stihle, M; Neumann, C; Müller, C; Schaefer, W; Klein, C; Benz, J

2017-09-01

An increasing number of bispecific therapeutic antibodies are progressing through clinical development. The Knob-into-Hole (KiH) technology uses complementary mutations in the CH3 region of the antibody Fc fragment to achieve heavy chain heterodimerization. Here we describe the X-ray crystal structures of glycosylated and disulfide-engineered heterodimeric KiH Fc fragment and its homodimeric Knob-Knob and Hole-Hole side products. The heterodimer structure confirms the KiH design principle and supports the hypothesis that glycosylation stabilizes a closed Fc conformation. Both homodimer structures show parallel Fc fragment architectures, in contrast to recently reported crystal structures of the corresponding aglycosylated Fc fragments which in the absence of disulfide mutations show an unexpected antiparallel arrangement. The glycosylated Knob-Knob Fc fragment is destabilized as indicated by variability in the relative orientation of its CH3 domains. The glycosylated Hole-Hole Fc fragment shows an unexpected intermolecular disulfide bond via the introduced Y349C Hole mutation which results in a large CH3 domain shift and a new CH3-CH3 interface. The crystal structures of glycosylated, disulfide-linked KiH Fc fragment and its Knob-Knob and Hole-Hole side products reported here will facilitate further design of highly efficient antibody heterodimerization strategies. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Metals and organochlorine pesticides in caudal scutes of crocodiles from Belize and Costa Rica

Energy Technology Data Exchange (ETDEWEB)

Rainwater, Thomas R. [Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409 (United States)]. E-mail: thomas.rainwater@tiehh.ttu.edu; Wu, Ted H. [Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409 (United States); Finger, Adam G. [Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409 (United States); Canas, Jaclyn E. [Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409 (United States); Yu Lu [Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409 (United States); Reynolds, Kevin D. [Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409 (United States); Coimbatore, Gopal [Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409 (United States); Barr, Brady [National Geographic Channel, 1145 17th St. NW Washington, DC 20036 (United States); Platt, Steven G. [Department of Biology, Box C-64, Sul Ross State University, Alpine, TX 79832 (United States); Cobb, George P. [Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409 (United States); Anderson, Todd A. [Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409 (United States); McMurry, Scott T. [Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409 (United States)

2007-02-01

Despite high animal diversity in the Neotropics and the largely unregulated use and disposal of pesticides and industrial chemicals in Central America, few data exist regarding accumulation of environmental contaminants in Central American wildlife. In this study we examined accumulation of metals and organochlorine (OC) pesticides in caudal scutes of crocodiles from Belize and Costa Rica. Scutes from Morelet's crocodiles (Crocodylus moreletii) from two sites in northern Belize were analyzed for metals, and scutes from American crocodiles (C. acutus) from one site in Costa Rica were analyzed for metals and OC pesticides. All scutes (n = 25; one scute from each of 25 individuals) contained multiple contaminants. Mercury was the predominant metal detected, occurring in all scutes examined from both species. Other metals detected include cadmium, copper, lead, and zinc. American crocodile scutes from Costa Rica contained multiple OC pesticides, including endrin, methoxychlor, p,p'-DDE, and p,p'-DDT, all of which occurred in 100% of scutes analyzed (n = 6). Mean metal and OC concentrations varied in relation to those previously reported in crocodilian scutes from other localities in North, Central, and South America. OC concentrations in American crocodile scutes were generally higher than those previously reported for other Costa Rican wildlife. Currently, caudal scutes may serve as general, non-lethal indicators of contaminant accumulation in crocodilians and their areas of occurrence. However, a better understanding of the relationships between pollutant concentrations in scutes, internal tissues, and environmental matrices at sample collection sites are needed to improve the utility of scutes in future ecotoxicological investigations.

Metals and organochlorine pesticides in caudal scutes of crocodiles from Belize and Costa Rica

International Nuclear Information System (INIS)

Rainwater, Thomas R.; Wu, Ted H.; Finger, Adam G.; Canas, Jaclyn E.; Yu Lu; Reynolds, Kevin D.; Coimbatore, Gopal; Barr, Brady; Platt, Steven G.; Cobb, George P.; Anderson, Todd A.; McMurry, Scott T.

2007-01-01

Despite high animal diversity in the Neotropics and the largely unregulated use and disposal of pesticides and industrial chemicals in Central America, few data exist regarding accumulation of environmental contaminants in Central American wildlife. In this study we examined accumulation of metals and organochlorine (OC) pesticides in caudal scutes of crocodiles from Belize and Costa Rica. Scutes from Morelet's crocodiles (Crocodylus moreletii) from two sites in northern Belize were analyzed for metals, and scutes from American crocodiles (C. acutus) from one site in Costa Rica were analyzed for metals and OC pesticides. All scutes (n = 25; one scute from each of 25 individuals) contained multiple contaminants. Mercury was the predominant metal detected, occurring in all scutes examined from both species. Other metals detected include cadmium, copper, lead, and zinc. American crocodile scutes from Costa Rica contained multiple OC pesticides, including endrin, methoxychlor, p,p'-DDE, and p,p'-DDT, all of which occurred in 100% of scutes analyzed (n = 6). Mean metal and OC concentrations varied in relation to those previously reported in crocodilian scutes from other localities in North, Central, and South America. OC concentrations in American crocodile scutes were generally higher than those previously reported for other Costa Rican wildlife. Currently, caudal scutes may serve as general, non-lethal indicators of contaminant accumulation in crocodilians and their areas of occurrence. However, a better understanding of the relationships between pollutant concentrations in scutes, internal tissues, and environmental matrices at sample collection sites are needed to improve the utility of scutes in future ecotoxicological investigations

Characterization of a novel caudal vertebral interbody fusion in a rat tail model: An implication for future material and mechanical testing

Directory of Open Access Journals (Sweden)

Yu-Cheng Yeh

2017-02-01

Conclusion: The rat caudal disc interbody fusion model proved to be an efficient, repeatable and easily accessible model. Future research into adjuvant treatments like growth factor injection and alternative fusion materials under conditions of osteoporosis using this model would be worthwhile.

Internal structure of black holes

International Nuclear Information System (INIS)

Cvetic, Mirjam

2013-01-01

Full text: We review recent progress that sheds light on the internal structure of general black holes. We first summarize properties of general multi-charged rotating black holes both in four and five dimensions. We show that the asymptotic boundary conditions of these general asymptotically flat black holes can be modified such that a conformal symmetry emerges. These subtracted geometries preserve the thermodynamic properties of the original black holes and are of the Lifshitz type, thus describing 'a black hole in the asymptotically conical box'. Recent efforts employ solution generating techniques to construct interpolating geometries between the original black hole and their subtracted geometries. Upon lift to one dimension higher, these geometries lift to AdS 3 times a sphere, and thus provide a microscopic interpretation of the black hole entropy in terms of dual two-dimensional conformal field theory. (author)

What is black hole?

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. What is black hole? Possible end phase of a star: A star is a massive, luminous ball of plasma having continuous nuclear burning. Star exhausts nuclear fuel →. White Dwarf, Neutron Star, Black Hole. Black hole's gravitational field is so powerful that even ...

Quantum effects in black holes

International Nuclear Information System (INIS)

Frolov, V.P.

1979-01-01

A strict definition of black holes is presented and some properties with regard to their mass are enumerated. The Hawking quantum effect - the effect of vacuum instability in the black hole gravitational field, as a result of shich the black hole radiates as a heated body is analyzed. It is shown that in order to obtain results on the black hole radiation it is sufficient to predetermine the in-vacuum state at a time moment in the past, when the collapsing body has a large size, and its gravitational field can be neglected. The causes and the place of particle production by the black hole, and also the space-time inside the black hole, are considered

Effects of ketamine and midazolam on emergence agitation after sevoflurane anaesthesia in children receiving caudal block: a randomized trial

Directory of Open Access Journals (Sweden)

Ayse Ozcan

2014-12-01

Full Text Available Background and objectives: Emergence agitation is a common postanaesthetic problem in children after sevoflurane anaesthesia. We aimed to compare the effects of ketamine and midazolam administered intravenously, before the end of surgery, for prevention of emergence agitation in children who received caudal block for pain relief under sevoflurane anaesthesia. Methods: 62 American Society of Anesthesiologists patient classification status I children, aged 2–7 years, scheduled for inguinal hernia repair, circumcision or orchidopexy were enrolled to the study. Anaesthesia was induced with sevoflurane 8% in a mixture of 50% oxygen and nitrous oxide. After achieving adequate depth of anaesthesia, a laryngeal mask was placed and then caudal block was performed with 0.75 mL kg−1, 0.25% bupivacaine. At the end of the surgery, ketamine 0.25 mg kg−1, midazolam 0.03 mg kg−1 and saline were given to ketamine, midazolam and control groups, respectively. Agitation was assessed using Paediatric Anaesthesia Emergence Delirium scale and postoperative pain was evaluated with modified Children's Hospital of Eastern Ontario Pain Scale. Results and conclusions: Modified Children's Hospital of Eastern Ontario Pain Scale scores were found higher in control group than in ketamine and midazolam groups. Paediatric Anaesthesia Emergence Delirium scores were similar between groups. Modified Children's Hospital of Eastern Ontario Pain Scale and Paediatric Anaesthesia Emergence Delirium scores showed a significant decrease by time in all groups during follow-up in postanaesthesia care unit. The present study resulted in satisfactory Paediatric Anaesthesia Emergence Delirium scores which are below 10 in all groups. As a conclusion, neither ketamine nor midazolam added to caudal block under sevoflurane anaesthesia did show further effect on emergence agitation. In addition, pain relief still seems to be the major factor in preventing emergence agitation after

Pitch Variability in Patients with Parkinson's Disease: Effects of Deep Brain Stimulation of Caudal Zona Incerta and Subthalamic Nucleus

Science.gov (United States)

Karlsson, Fredrik; Olofsson, Katarina; Blomstedt, Patric; Linder, Jan; van Doorn, Jan

2013-01-01

Purpose: The purpose of the present study was to examine the effect of deep brain stimulation (DBS) of the subthalamic nucleus (STN) and the caudal zona incerta (cZi) pitch characteristics of connected speech in patients with Parkinson's disease (PD). Method: The authors evaluated 16 patients preoperatively and 12 months after DBS surgery. Eight…

30 CFR 57.7055 - Intersecting holes.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Intersecting holes. 57.7055 Section 57.7055... Jet Piercing Drilling-Surface and Underground § 57.7055 Intersecting holes. Holes shall not be drilled where there is a danger of intersecting a misfired hole or a hole containing explosives, blasting agents...

30 CFR 56.7055 - Intersecting holes.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Intersecting holes. 56.7055 Section 56.7055... Piercing Drilling § 56.7055 Intersecting holes. Holes shall not be drilled where there is a danger of intersecting a misfired hole or a hole containing explosives blasting agents, or detonators. [56 FR 46508, Sept...

Wernekink Commissure Syndrome Secondary to Bilateral Caudal Paramedian Midbrain Infarction Presenting with a Unique “Heart or V” Appearance Sign: Case Report and Review of the Literature

Directory of Open Access Journals (Sweden)

Chenguang Zhou

2017-08-01

Full Text Available Wernekink commissure syndrome secondary to caudal paramedian midbrain infarction (CPMI is a rare midbrain syndrome involving the decussation of the superior cerebellar peduncle in the caudal paramedian midbrain tegmentum. The central characteristics are constant bilateral cerebellar dysfunction, variable eye movement disorders, and rare delayed palatal myoclonus. Following is a description of the case of a 60-year-old man who presented with dizziness, slurred speech, and difficulty walking. Neurological examination revealed bilateral cerebellar dysfunction and bilateral internuclear ophthalmoplegia (bilateral INO. Serial magnetic resonance imaging (MRI revealed a lesion in the caudal paramedian midbrain with a “heart-shaped” sign on fluid-attenuation inversion recovery images and a “V-shaped” appearance on diffusion-weighted imaging (DWI. An acute CPMI with a “heart or V” appearance sign was diagnosed. Upon follow-up evaluation 3 months later, a palatal tremor accompanied by involuntary head tremor was discovered. Hypertrophy and increased signal of the bilateral inferior olivary nucleus, compatible with hypertropic olivary degeneration (HOD were revealed during a subsequent MRI study.

Evaluation of Artificial Caudal Fin for Fish Robot with Two Joints by Using Three-Dimensional Fluid-Structure Simulation

Directory of Open Access Journals (Sweden)

Yogo Takada

2013-01-01

Full Text Available A fish robot with image sensors is useful to research for underwater creatures such as fish. However, the propulsion velocity of a fish robot is very slow compared with live fish. It is necessary to swim at a speed several times faster than the speed of the current robots for various usages. Therefore, we are searching for the method of making the robot swim fast. The simulation before making the robot is important. We have made the computational simulation program of three-dimensional fluid-structure analysis. The flow around the caudal fin can be examined by analyzing the fin as an elastic body. We compared the results of numerical analysis with the results of PIV measurement. Both were agreed well. Because the performance of a fish robot with two joints is better than that of a fish robot with one joint, we searched for an excellent fin for the fish robot with two joints by using CFD. We confirmed that the swimming performance of a fish robot becomes very good when the caudal fin is rigid except for the root of the fin which is comparatively flexible.

Lifshitz topological black holes

International Nuclear Information System (INIS)

Mann, R.B.

2009-01-01

I find a class of black hole solutions to a (3+1) dimensional theory gravity coupled to abelian gauge fields with negative cosmological constant that has been proposed as the dual theory to a Lifshitz theory describing critical phenomena in (2+1) dimensions. These black holes are all asymptotic to a Lifshitz fixed point geometry and depend on a single parameter that determines both their area (or size) and their charge. Most of the solutions are obtained numerically, but an exact solution is also obtained for a particular value of this parameter. The thermodynamic behaviour of large black holes is almost the same regardless of genus, but differs considerably for small black holes. Screening behaviour is exhibited in the dual theory for any genus, but the critical length at which it sets in is genus-dependent for small black holes.

Black hole decay as geodesic motion

International Nuclear Information System (INIS)

Gupta, Kumar S.; Sen, Siddhartha

2003-01-01

We show that a formalism for analyzing the near-horizon conformal symmetry of Schwarzschild black holes using a scalar field probe is capable of describing black hole decay. The equation governing black hole decay can be identified as the geodesic equation in the space of black hole masses. This provides a novel geometric interpretation for the decay of black holes. Moreover, this approach predicts a precise correction term to the usual expression for the decay rate of black holes

Drilling miniature holes, Part III

Energy Technology Data Exchange (ETDEWEB)

Gillespie, L.K.

1978-07-01

Miniature components for precision electromechanical mechanisms such as switches, timers, and actuators typically require a number of small holes. Because of the precision required, the workpiece materials, and the geometry of the parts, most of these holes must be produced by conventional drilling techniques. The use of such techniques is tedious and often requires considerable trial and error to prevent drill breakage, minimize hole mislocation and variations in hole diameter. This study of eight commercial drill designs revealed that printed circuit board drills produced better locational and size repeatability than did other drills when centerdrilling was not used. Boring holes 1 mm in dia, or less, as a general rule did not improve hole location in brass or stainless steel. Hole locations of patterns of 0.66-mm holes can be maintained within 25.4-..mu..m diametral positional tolerance if setup misalignments can be eliminated. Size tolerances of +- 3.8 ..mu..m can be maintained under some conditions when drilling flat plates. While these levels of precision are possible with existing off-the-shelf drills, they may not be practical in many cases.

Acceleration of black hole universe

Science.gov (United States)

Zhang, T. X.; Frederick, C.

2014-01-01

Recently, Zhang slightly modified the standard big bang theory and developed a new cosmological model called black hole universe, which is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, and cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This paper investigates acceleration of the black hole universe and provides an alternative explanation for the redshift and luminosity distance measurements of type Ia supernovae. The results indicate that the black hole universe accelerates its expansion when it accretes the ambient matter in an increasing rate. In other words, i.e., when the second-order derivative of the mass of the black hole universe with respect to the time is positive . For a constant deceleration parameter , we can perfectly explain the type Ia supernova measurements with the reduced chi-square to be very close to unity, χ red˜1.0012. The expansion and acceleration of black hole universe are driven by external energy.

Super-horizon primordial black holes

International Nuclear Information System (INIS)

Harada, Tomohiro; Carr, B.J.

2005-01-01

We discuss a new class of solutions to the Einstein equations which describe a primordial black hole (PBH) in a flat Friedmann background. Such solutions arise if a Schwarzschild black hole is patched onto a Friedmann background via a transition region. They are possible providing the black hole event horizon is larger than the cosmological apparent horizon. Such solutions have a number of strange features. In particular, one has to define the black hole and cosmological horizons carefully and one then finds that the mass contained within the black hole event horizon decreases when the black hole is larger than the Friedmann cosmological apparent horizon, although its area always increases. These solutions involve two distinct future null infinities and are interpreted as the conversion of a white hole into a black hole. Although such solutions may not form from gravitational collapse in the same way as standard PBHs, there is nothing unphysical about them, since all energy and causality conditions are satisfied. Their conformal diagram is a natural amalgamation of the Kruskal diagram for the extended Schwarzschild solution and the conformal diagram for a black hole in a flat Friedmann background. In this paper, such solutions are obtained numerically for a spherically symmetric universe containing a massless scalar field, but it is likely that they exist for more general matter fields and less symmetric systems

Caudal regression syndrome and sirenomelia in only one twin in two diabetic pregnancies.

Science.gov (United States)

Assimakopoulos, E; Athanasiadis, A; Zafrakas, M; Dragoumis, K; Bontis, J

2004-01-01

Many authors consider sirenomelia to be an extreme form of caudal regression syndrome (CRS), while others argue that they are two distinct entities. Maternal diabetes mellitus is considered to be an important predisposing factor for both CRS and sirenomelia. Two rare cases of diabetic, dizygotic twin pregnancies, each with one normal and one affected fetus are presented. In case 1 the affected fetus had CRS. In case 2 the affected fetus had sirenomelia. The present cases suggest that the pathogenesis of CRS and sirenomelia is more complex than previously thought, that maternal diabetes is not the only underlying pathogenetic mechanism and that genetic or epigenetic factors probably contribute to the formation of these conditions.

Acute traumatic brain-stem hemorrhage produced by sudden caudal displacement of the brain

International Nuclear Information System (INIS)

Mirvis, S.E.; Wolf, A.L.; Thompson, R.K.

1990-01-01

This paper determines in an experimental canine study and a clinical review, whether acute caudal displacement of the brain following blunt trauma produces hemorrhage in the rostral anterior midline of the brain stem by tethering the basilar to the fixed carotid arteries. In four dogs, a balloon catheter was suddenly inflated over the frontal lobe; in two, the carotid-basilar vascular connections were severed prior to balloon inflation. ICP was monitored during and after balloon inflation. Hemorrhage was verified by MR imaging and direct inspection of the fixed brain specimens. Admission CT scans demonstrating acute traumatic brain stem hemorrhage (TBH) in human patients were reviewed to determine the site of TBH, predominant site of impact, and neurologic outcome

NASA Observatory Confirms Black Hole Limits

Science.gov (United States)

2005-02-01

The very largest black holes reach a certain point and then grow no more, according to the best survey to date of black holes made with NASA's Chandra X-ray Observatory. Scientists have also discovered many previously hidden black holes that are well below their weight limit. These new results corroborate recent theoretical work about how black holes and galaxies grow. The biggest black holes, those with at least 100 million times the mass of the Sun, ate voraciously during the early Universe. Nearly all of them ran out of 'food' billions of years ago and went onto a forced starvation diet. Focus on Black Holes in the Chandra Deep Field North Focus on Black Holes in the Chandra Deep Field North On the other hand, black holes between about 10 and 100 million solar masses followed a more controlled eating plan. Because they took smaller portions of their meals of gas and dust, they continue growing today. "Our data show that some supermassive black holes seem to binge, while others prefer to graze", said Amy Barger of the University of Wisconsin in Madison and the University of Hawaii, lead author of the paper describing the results in the latest issue of The Astronomical Journal (Feb 2005). "We now understand better than ever before how supermassive black holes grow." One revelation is that there is a strong connection between the growth of black holes and the birth of stars. Previously, astronomers had done careful studies of the birthrate of stars in galaxies, but didn't know as much about the black holes at their centers. DSS Optical Image of Lockman Hole DSS Optical Image of Lockman Hole "These galaxies lose material into their central black holes at the same time that they make their stars," said Barger. "So whatever mechanism governs star formation in galaxies also governs black hole growth." Astronomers have made an accurate census of both the biggest, active black holes in the distance, and the relatively smaller, calmer ones closer by. Now, for the first

Green's tensor calculations of plasmon resonances of single holes and hole pairs in thin gold films

International Nuclear Information System (INIS)

Alegret, Joan; Kaell, Mikael; Johansson, Peter

2008-01-01

We present numerical calculations of the plasmon properties of single-hole and hole-pair structures in optically thin gold films obtained with the Green's tensor formalism for stratified media. The method can be used to obtain the optical properties of a given hole system, without problems associated with the truncation of the infinite metal film. The calculations are compared with previously published experimental data and an excellent agreement is found. In particular, the calculations are shown to reproduce the evolution of the hole plasmon resonance spectrum as a function of hole diameter, film thickness and hole separation.

Curvature invariant characterization of event horizons of four-dimensional black holes conformal to stationary black holes

Science.gov (United States)

McNutt, David D.

2017-11-01

We introduce three approaches to generate curvature invariants that transform covariantly under a conformal transformation of a four-dimensional spacetime. For any black hole conformally related to a stationary black hole, we show how a set of conformally covariant invariants can be combined to produce a conformally covariant invariant that detects the event horizon of the conformally related black hole. As an application we consider the rotating dynamical black holes conformally related to the Kerr-Newman-Unti-Tamburino-(anti)-de Sitter spacetimes and construct an invariant that detects the conformal Killing horizon along with a second invariant that detects the conformal stationary limit surface. In addition, we present necessary conditions for a dynamical black hole to be conformally related to a stationary black hole and apply these conditions to the ingoing Kerr-Vaidya and Vaidya black hole solutions to determine if they are conformally related to stationary black holes for particular choices of the mass function. While two of the three approaches cannot be generalized to higher dimensions, we discuss the existence of a conformally covariant invariant that will detect the event horizon for any higher dimensional black hole conformally related to a stationary black hole which admits at least two conformally covariant invariants, including all vacuum spacetimes.

Statistical mechanics of black holes

International Nuclear Information System (INIS)

Harms, B.; Leblanc, Y.

1992-01-01

We analyze the statistical mechanics of a gas of neutral and charged black holes. The microcanonical ensemble is the only possible approach to this system, and the equilibrium configuration is the one for which most of the energy is carried by a single black hole. Schwarzschild black holes are found to obey the statistical bootstrap condition. In all cases, the microcanonical temperature is identical to the Hawking temperature of the most massive black hole in the gas. U(1) charges in general break the bootstrap property. The problems of black-hole decay and of quantum coherence are also addressed

Regular black hole in three dimensions

OpenAIRE

Myung, Yun Soo; Yoon, Myungseok

2008-01-01

We find a new black hole in three dimensional anti-de Sitter space by introducing an anisotropic perfect fluid inspired by the noncommutative black hole. This is a regular black hole with two horizons. We compare thermodynamics of this black hole with that of non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy.

Black hole levitron

NARCIS (Netherlands)

Arsiwalla, X.D.; Verlinde, E.P.

2010-01-01

We study the problem of spatially stabilizing four dimensional extremal black holes in background electric/magnetic fields. Whilst looking for stationary stable solutions describing black holes placed in external fields we find that taking a continuum limit of Denef et al.’s multicenter

Bloqueio peridural caudal: técnica anestésica de uso exclusivo em crianças? É possível sua realização em adultos? Qual o papel do ultrassom nesse contexto?

Directory of Open Access Journals (Sweden)

Ilana Esquenazi Najman

2011-02-01

Full Text Available JUSTIFICATIVA E OBJETIVOS: O bloqueio peridural caudal é a mais popular entre todas as técnicas de anestesia regional em crianças. Com o avanço da idade, apenas a relativa dificuldade em localizar o hiato sacral limita seu uso. Entretanto, em adultos a técnica vem sendo largamente utilizada para controle de dor crônica com o auxílio da fluoroscopia. Assim, a habilidade em localizar o hiato e definir as variações anatômicas é o principal fator determinante do sucesso e segurança na execução do bloqueio peridural pela via caudal. Nesse contexto, o ultrassom vem ganhando espaço como guia para a realização do bloqueio caudal. O objetivo desta revisão foi elucidar o papel do ultrassom na anestesia caudal, além de demonstrar que o bloqueio caudal, muito utilizado em crianças, também é útil e pode ser usado em adultos. CONTEÚDO: Uma revisão literária sobre a anatomia da região sacral e da técnica anestésica necessária para a realização adequada do bloqueio caudal foi promovida. Além disso, artigos recentes sobre estudos realizados com bloqueios peridurais caudais guiados por ultrassom tanto em crianças quanto em adultos também foram incluídos. CONCLUSÕES: O ultrassom, apesar de suas limitações, pode ser útil como ferramenta adjuvante no posicionamento da agulha no espaço caudal. Permite a fácil identificação da anatomia sacral, além de visualização da injeção, em tempo real. Sua natureza portátil, não invasiva e livre de exposição à radiação faz dele uma tecnologia atrativa na sala operatória, principalmente na emergência de casos difíceis. Entretanto, como seu uso em bloqueios centrais do neuroeixo ainda é muito primitivo, é necessário que mais pesquisas sejam feitas para se consagre como técnica de rotina na prática anestésica.

Is there life inside black holes?

International Nuclear Information System (INIS)

Dokuchaev, V I

2011-01-01

Bound inside rotating or charged black holes, there are stable periodic planetary orbits, which neither come out nor terminate at the central singularity. Stable periodic orbits inside black holes exist even for photons. These bound orbits may be defined as orbits of the third kind, following the Chandrasekhar classification of particle orbits in the black hole gravitational field. The existence domain for the third-kind orbits is rather spacious, and thus there is place for life inside supermassive black holes in the galactic nuclei. Interiors of the supermassive black holes may be inhabited by civilizations, being invisible from the outside. In principle, one can get information from the interiors of black holes by observing their white hole counterparts. (paper)

Black Hole Grabs Starry Snack

Science.gov (United States)

2006-01-01

[figure removed for brevity, see original site] Poster Version This artist's concept shows a supermassive black hole at the center of a remote galaxy digesting the remnants of a star. NASA's Galaxy Evolution Explorer had a 'ringside' seat for this feeding frenzy, using its ultraviolet eyes to study the process from beginning to end. The artist's concept chronicles the star being ripped apart and swallowed by the cosmic beast over time. First, the intact sun-like star (left) ventures too close to the black hole, and its own self-gravity is overwhelmed by the black hole's gravity. The star then stretches apart (middle yellow blob) and eventually breaks into stellar crumbs, some of which swirl into the black hole (cloudy ring at right). This doomed material heats up and radiates light, including ultraviolet light, before disappearing forever into the black hole. The Galaxy Evolution Explorer was able to watch this process unfold by observing changes in ultraviolet light. The area around the black hole appears warped because the gravity of the black hole acts like a lens, twisting and distorting light.

A nonsingular rotating black hole

International Nuclear Information System (INIS)

Ghosh, Sushant G.

2015-01-01

The spacetime singularities in classical general relativity are inevitable, as predicated by the celebrated singularity theorems. However, it is a general belief that singularities do not exist in Nature and that they are the limitations of the general relativity. In the absence of a welldefined quantum gravity, models of regular black holes have been studied. We employ a probability distribution inspired mass function m(r) to replace the Kerr black hole mass M to represent a nonsingular rotating black hole that is identified asymptotically (r >> k, k > 0 constant) exactly as the Kerr-Newman black hole, and as the Kerr black hole when k = 0. The radiating counterpart renders a nonsingular generalization of Carmeli's spacetime as well as Vaidya's spacetime, in the appropriate limits. The exponential correction factor changing the geometry of the classical black hole to remove the curvature singularity can also be motivated by quantum arguments. The regular rotating spacetime can also be understood as a black hole of general relativity coupled to nonlinear electrodynamics. (orig.)

Thermodynamic theory of black holes

Energy Technology Data Exchange (ETDEWEB)

Davies, P C.W. [King' s Coll., London (UK). Dept. of Mathematics

1977-04-21

The thermodynamic theory underlying black hole processes is developed in detail and applied to model systems. It is found that Kerr-Newman black holes undergo a phase transition at a = 0.68M or Q = 0.86M, where the heat capacity has an infinite discontinuity. Above the transition values the specific heat is positive, permitting isothermal equilibrium with a surrounding heat bath. Simple processes and stability criteria for various black hole situations are investigated. The limits for entropically favoured black hole formation are found. The Nernst conditions for the third law of thermodynamics are not satisfied fully for black holes. There is no obvious thermodynamic reason why a black hole may not be cooled down below absolute zero and converted into a naked singularity. Quantum energy-momentum tensor calculations for uncharged black holes are extended to the Reissner-Nordstrom case, and found to be fully consistent with the thermodynamic picture for Q < M. For Q < M the model predicts that 'naked' collapse also produces radiation, with such intensity that the collapsing matter is entirely evaporated away before a naked singularity can form.

Erratic Black Hole Regulates Itself

Science.gov (United States)

2009-03-01

New results from NASA's Chandra X-ray Observatory have made a major advance in explaining how a special class of black holes may shut off the high-speed jets they produce. These results suggest that these black holes have a mechanism for regulating the rate at which they grow. Black holes come in many sizes: the supermassive ones, including those in quasars, which weigh in at millions to billions of times the mass of the Sun, and the much smaller stellar-mass black holes which have measured masses in the range of about 7 to 25 times the Sun's mass. Some stellar-mass black holes launch powerful jets of particles and radiation, like seen in quasars, and are called "micro-quasars". The new study looks at a famous micro-quasar in our own Galaxy, and regions close to its event horizon, or point of no return. This system, GRS 1915+105 (GRS 1915 for short), contains a black hole about 14 times the mass of the Sun that is feeding off material from a nearby companion star. As the material swirls toward the black hole, an accretion disk forms. This system shows remarkably unpredictable and complicated variability ranging from timescales of seconds to months, including 14 different patterns of variation. These variations are caused by a poorly understood connection between the disk and the radio jet seen in GRS 1915. Chandra, with its spectrograph, has observed GRS 1915 eleven times since its launch in 1999. These studies reveal that the jet in GRS 1915 may be periodically choked off when a hot wind, seen in X-rays, is driven off the accretion disk around the black hole. The wind is believed to shut down the jet by depriving it of matter that would have otherwise fueled it. Conversely, once the wind dies down, the jet can re-emerge. "We think the jet and wind around this black hole are in a sort of tug of war," said Joseph Neilsen, Harvard graduate student and lead author of the paper appearing in the journal Nature. "Sometimes one is winning and then, for reasons we don

Nonsingular black hole

Energy Technology Data Exchange (ETDEWEB)

Chamseddine, Ali H. [American University of Beirut, Physics Department, Beirut (Lebanon); I.H.E.S., Bures-sur-Yvette (France); Mukhanov, Viatcheslav [Niels Bohr Institute, Niels Bohr International Academy, Copenhagen (Denmark); Ludwig-Maximilians University, Theoretical Physics, Munich (Germany); MPI for Physics, Munich (Germany)

2017-03-15

We consider the Schwarzschild black hole and show how, in a theory with limiting curvature, the physical singularity ''inside it'' is removed. The resulting spacetime is geodesically complete. The internal structure of this nonsingular black hole is analogous to Russian nesting dolls. Namely, after falling into the black hole of radius r{sub g}, an observer, instead of being destroyed at the singularity, gets for a short time into the region with limiting curvature. After that he re-emerges in the near horizon region of a spacetime described by the Schwarzschild metric of a gravitational radius proportional to r{sub g}{sup 1/3}. In the next cycle, after passing the limiting curvature, the observer finds himself within a black hole of even smaller radius proportional to r{sub g}{sup 1/9}, and so on. Finally after a few cycles he will end up in the spacetime where he remains forever at limiting curvature. (orig.)

EVALUACIÓN DEL COMPORTAMIENTO HIDRÁULICO DE DOCE MODELOS DE GOTEROS DE BAJO CAUDAL

OpenAIRE

Pastor J., Rocío; Universidad Nacional Agraria La Molina, Lima, Perú.; Narro D., Ángel; Universidad Nacional Agraria La Molina, Lima, Perú.

2015-01-01

La investigación se realizó en el laboratorio de Riego y Drenaje de la Facultad de Ingeniería Agrícola, de la Universidad Nacional Agraria La Molina. El objetivo fue determinar el coeficiente de variación y las curvas caudal-presión de 12 modelos de goteros. Las mangueras fueron evaluadas en un banco de pruebas que consta de una estructura de soporte que sostiene a la bandeja de captación. Las dimensiones son 2,0 m de largo por 1,0 m de ancho y la estructura de conducción de 0,45 m de largo p...

Axion-dilation black holes

International Nuclear Information System (INIS)

Kallosh, R.

1993-01-01

In this talk some essential features of stringy black holes are described. The author considers charged U(1) and U(1) x U(1) four-dimensional axion-dilaton black holes. The Hawking temperature and the entropy of all solutions are shown to be simple functions of the squares of supercharges, defining the positivity bounds. Spherically symmetric and multi black hole solutions are presented. The extreme solutions with zero entropy (holons) represent a ground state of the theory and are characterized by elementary dilaton, axion, electric, and magnetic charges. The attractive gravitational and axion-dilaton force is balanced by the repulsive electromagnetic force. The author discusses the possibility of splitting of nearly extreme black holes. 11 refs

ResonantSonic drilling. Innovative technology summary report

International Nuclear Information System (INIS)

1995-04-01

The technology of ResonantSonic drilling is described. This technique has been demonstrated and deployed as an innovative tool to access the subsurface for installation of monitoring and/or remediation wells and for collection of subsurface materials for environmental restoration applications. The technology uses no drilling fluids, is safe and can be used to drill slant holes

What Can We Learn About Black-Hole Formation from Black-Hole X-ray Binaries?

NARCIS (Netherlands)

Nelemans, G.A.

2007-01-01

I discuss the effect of the formation of a black hole on a (close) binary and show some of the current constraints that the observed properties of black hole X-ray binaries put on the formation of black holes. In particular, I discuss the evidence for and against asymmetric kicks imparted on the

Quantum capacity of quantum black holes

Science.gov (United States)

Adami, Chris; Bradler, Kamil

2014-03-01

The fate of quantum entanglement interacting with a black hole has been an enduring mystery, not the least because standard curved space field theory does not address the interaction of black holes with matter. We discuss an effective Hamiltonian of matter interacting with a black hole that has a precise analogue in quantum optics and correctly reproduces both spontaneous and stimulated Hawking radiation with grey-body factors. We calculate the quantum capacity of this channel in the limit of perfect absorption, as well as in the limit of a perfectly reflecting black hole (a white hole). We find that the white hole is an optimal quantum cloner, and is isomorphic to the Unruh channel with positive quantum capacity. The complementary channel (across the horizon) is entanglement-breaking with zero capacity, avoiding a violation of the quantum no-cloning theorem. The black hole channel on the contrary has vanishing capacity, while its complement has positive capacity instead. Thus, quantum states can be reconstructed faithfully behind the black hole horizon, but not outside. This work sheds new light on black hole complementarity because it shows that black holes can both reflect and absorb quantum states without violating the no-cloning theorem, and makes quantum firewalls obsolete.

Response Function of the Crayfish Caudal Photoreceptor to Hydrodynamic Stimuli

Science.gov (United States)

Breite, Sally; Bahar, Sonya; Neiman, Alexander; Moss, Frank

2002-03-01

In its abdominal 6th ganglion the crayfish houses 2 light-sensitive neurons (caudal photoreceptors, or CPRs). It is known that these neurons work in tandem with a mechanosensory system of tiny hairs spread across the tailfan, which make synaptic contact with the photoreceptors. A stochastic resonance effect has been shown in this system in which light enhances the transduction of a weak, periodic mechanosensory (hydrodynamic) stimulus. It is not known, however, whether an optimal response from the CPR is induced by a single sine wave cycle or some other waveform. We have experimentally investigated this favorable waveform by driving a tailfan preparation with mechanical 10 Hz correlated Ornstein-Uhlenbeck noise and calculating the response function from the spike-triggered average of the applied noise waveform. We will discuss differences in the shape of the optimal waveform under dark and light conditions, as well as what seems to be a noticeable difference in the magnitude of the animals' response to a noisy stimulus in comparison with a periodic stimulus.

Black holes and the multiverse

International Nuclear Information System (INIS)

Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun

2016-01-01

Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse

Black holes and the multiverse

Energy Technology Data Exchange (ETDEWEB)

Garriga, Jaume [Departament de Fisica Fonamental i Institut de Ciencies del Cosmos, Universitat de Barcelona, Marti i Franques, 1, Barcelona, 08028 Spain (Spain); Vilenkin, Alexander; Zhang, Jun, E-mail: jaume.garriga@ub.edu, E-mail: vilenkin@cosmos.phy.tufts.edu, E-mail: jun.zhang@tufts.edu [Institute of Cosmology, Tufts University, 574 Boston Ave, Medford, MA, 02155 (United States)

2016-02-01

Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse.

Anyon black holes

Science.gov (United States)

Aghaei Abchouyeh, Maryam; Mirza, Behrouz; Karimi Takrami, Moein; Younesizadeh, Younes

2018-05-01

We propose a correspondence between an Anyon Van der Waals fluid and a (2 + 1) dimensional AdS black hole. Anyons are particles with intermediate statistics that interpolates between a Fermi-Dirac statistics and a Bose-Einstein one. A parameter α (0 quasi Fermi-Dirac statistics for α >αc, but a quasi Bose-Einstein statistics for α quasi Bose-Einstein statistics. For α >αc and a range of values of the cosmological constant, there is, however, no event horizon so there is no black hole solution. Thus, for these values of cosmological constants, the AdS Anyon Van der Waals black holes have only quasi Bose-Einstein statistics.

ULTRAMASSIVE BLACK HOLE COALESCENCE

International Nuclear Information System (INIS)

Khan, Fazeel Mahmood; Holley-Bockelmann, Kelly; Berczik, Peter

2015-01-01

Although supermassive black holes (SMBHs) correlate well with their host galaxies, there is an emerging view that outliers exist. Henize 2-10, NGC 4889, and NGC 1277 are examples of SMBHs at least an order of magnitude more massive than their host galaxy suggests. The dynamical effects of such ultramassive central black holes is unclear. Here, we perform direct N-body simulations of mergers of galactic nuclei where one black hole is ultramassive to study the evolution of the remnant and the black hole dynamics in this extreme regime. We find that the merger remnant is axisymmetric near the center, while near the large SMBH influence radius, the galaxy is triaxial. The SMBH separation shrinks rapidly due to dynamical friction, and quickly forms a binary black hole; if we scale our model to the most massive estimate for the NGC 1277 black hole, for example, the timescale for the SMBH separation to shrink from nearly a kiloparsec to less than a parsec is roughly 10 Myr. By the time the SMBHs form a hard binary, gravitational wave emission dominates, and the black holes coalesce in a mere few Myr. Curiously, these extremely massive binaries appear to nearly bypass the three-body scattering evolutionary phase. Our study suggests that in this extreme case, SMBH coalescence is governed by dynamical friction followed nearly directly by gravitational wave emission, resulting in a rapid and efficient SMBH coalescence timescale. We discuss the implications for gravitational wave event rates and hypervelocity star production

When Supermassive Black Holes Wander

Science.gov (United States)

Kohler, Susanna

2018-05-01

Are supermassive black holes found only at the centers of galaxies? Definitely not, according to a new study in fact, galaxies like the Milky Way may harbor several such monsters wandering through their midst.Collecting Black Holes Through MergersIts generally believed that galaxies are built up hierarchically, growing in size through repeated mergers over time. Each galaxy in a major merger likely hosts a supermassive black hole a black hole of millions to billions of times the mass of the Sun at its center. When a pair of galaxies merges, their supermassive black holes will often sink to the center of the merger via a process known as dynamical friction. There the supermassive black holes themselves will eventually merge in a burst of gravitational waves.Spatial distribution and velocities of wandering supermassive black holes in three of the authors simulated galaxies, shown in edge-on (left) and face-on (right) views of the galaxy disks. Click for a closer look. [Tremmel et al. 2018]But if a galaxy the size of the Milky Way was built through a history of many major galactic mergers, are we sure that all its accumulated supermassive black holes eventually merged at the galactic center? A new study suggests that some of these giants might have escaped such a fate and they now wander unseen on wide orbits through their galaxies.Black Holes in an Evolving UniverseLed by Michael Tremmel (Yale Center for Astronomy Astrophysics), a team of scientists has used data from a large-scale cosmological simulation, Romulus25, to explore the possibility of wandering supermassive black holes. The Romulus simulations are uniquely suited to track the formation and subsequent orbital motion of supermassive black holes as galactic halos are built up through mergers over the history of the universe.From these simulations, Tremmel and collaborators find an end total of 316 supermassive black holes residing within the bounds of 26 Milky-Way-mass halos. Of these, roughly a third are

Black holes: the membrane paradigm

International Nuclear Information System (INIS)

Thorne, K.S.; Price, R.H.; Macdonald, D.A.

1986-01-01

The physics of black holes is explored in terms of a membrane paradigm which treats the event horizon as a two-dimensional membrane embedded in three-dimensional space. A 3+1 formalism is used to split Schwarzschild space-time and the laws of physics outside a nonrotating hole, which permits treatment of the atmosphere in terms of the physical properties of thin slices. The model is applied to perturbed slowly or rapidly rotating and nonrotating holes, and to quantify the electric and magnetic fields and eddy currents passing through a membrane surface which represents a stretched horizon. Features of tidal gravitational fields in the vicinity of the horizon, quasars and active galalctic nuclei, the alignment of jets perpendicular to accretion disks, and the effects of black holes at the center of ellipsoidal star clusters are investigated. Attention is also given to a black hole in a binary system and the interactions of black holes with matter that is either near or very far from the event horizon. Finally, a statistical mechanics treatment is used to derive a second law of thermodynamics for a perfectly thermal atmosphere of a black hole

Stationary black holes: large D analysis

International Nuclear Information System (INIS)

Suzuki, Ryotaku; Tanabe, Kentaro

2015-01-01

We consider the effective theory of large D stationary black holes. By solving the Einstein equations with a cosmological constant using the 1/D expansion in near zone of the black hole we obtain the effective equation for the stationary black hole. The effective equation describes the Myers-Perry black hole, bumpy black holes and, possibly, the black ring solution as its solutions. In this effective theory the black hole is represented as an embedded membrane in the background, e.g., Minkowski or Anti-de Sitter spacetime and its mean curvature is given by the surface gravity redshifted by the background gravitational field and the local Lorentz boost. The local Lorentz boost property of the effective equation is observed also in the metric itself. In fact we show that the leading order metric of the Einstein equation in the 1/D expansion is generically regarded as a Lorentz boosted Schwarzschild black hole. We apply this Lorentz boost property of the stationary black hole solution to solve perturbation equations. As a result we obtain an analytic formula for quasinormal modes of the singly rotating Myers-Perry black hole in the 1/D expansion.

Drilling history core hole DC-8

International Nuclear Information System (INIS)

1978-10-01

Core hole DC-8 was completed in August, 1978 by Boyles Brothers Drilling Company, Spokane, Washington, under subcontract to Fenix and Scission, Inc. The hole was cored for the US Department of Energy and the Rockwell Hanford Operations' Basalt Waste Isolation Program. Fenix and Scisson, Inc. furnished the engineering, daily supervision of the core drilling activities, and geologic core logging for hole DC-8. Core hole DC-8 is located on the Hanford Site near the Wye Barricade and 50 feet northwest of rotary hole DC-7. The Hanford Site vation coordinates for DC-8 are North 14,955.94 feet and West 14,861.92 coordinates for DC-8 are North 14,955.94 feet and West 14,861.92 mean sea level. The purpose of core hole DC-8 was to core drill vertically through the basalt and interbed units for stratigraphic depth determination and core collection, and to provide a borehole for hydrologic testing and cross-hole seismic shear and pressure wave velocity studies with rotary hole DC-7. The total depth of core hole DC-8 was 4100.5 feet. Core recovery exceeded 97 percent of the total footage cored

Drilling history core hole DC-8

Energy Technology Data Exchange (ETDEWEB)

1978-10-01

Core hole DC-8 was completed in August, 1978 by Boyles Brothers Drilling Company, Spokane, Washington, under subcontract to Fenix and Scission, Inc. The hole was cored for the US Department of Energy and the Rockwell Hanford Operations' Basalt Waste Isolation Program. Fenix and Scisson, Inc. furnished the engineering, daily supervision of the core drilling activities, and geologic core logging for hole DC-8. Core hole DC-8 is located on the Hanford Site near the Wye Barricade and 50 feet northwest of rotary hole DC-7. The Hanford Site vation coordinates for DC-8 are North 14,955.94 feet and West 14,861.92 coordinates for DC-8 are North 14,955.94 feet and West 14,861.92 mean sea level. The purpose of core hole DC-8 was to core drill vertically through the basalt and interbed units for stratigraphic depth determination and core collection, and to provide a borehole for hydrologic testing and cross-hole seismic shear and pressure wave velocity studies with rotary hole DC-7. The total depth of core hole DC-8 was 4100.5 feet. Core recovery exceeded 97 percent of the total footage cored.

Studies on density dependence of charge separation in a direct energy converter using slanted Cusp magnetic field

International Nuclear Information System (INIS)

Munakata, Yoshiro; Kawaguchi, Takashi; Takeno, Hiromasa; Yasaka, Yasuyoshi; Ichimura, Kazuya; Nakashima, Yousuke

2012-01-01

In an advanced fusion, fusion-produced charged particles must be separated from each other for efficient energy conversion to electricity. The CuspDEC performs this function of separation and direct energy conversion. Analysis of working characteristics of CuspDEC on plasma density is an important subject. This paper summarizes and discusses experimental and theoretical works for high density plasma by using a small scale experimental device employing a slanted cusp magnetic field. When the incident plasma is low-density, good separation of the charged particles can be accomplished and this is explained by the theory based on a single particle motion. In high density plasma, however, this theory cannot be always applied due to space charge effects. In the experiment, as gradient of the field line increases, separation capability of the charged particles becomes higher. As plasma density becomes higher, however, separation capability becomes lower. This can be qualitatively explained by using calculations of the modified Störmer potential including space charge potential. (author)

Auxillary system for optimizing simulation and percutaneous irradiation in cranio-caudally contiguous head-neck-mediastinum fields

International Nuclear Information System (INIS)

Sistermanns, J.

1994-01-01

Percutaneous irradiation in the head and neck region via opponing lateral fields with caudally contiguous ventral and/or dorsal fields makes very high demands on simulation, instrument adjustment and documentation. At the outer boundaries of the irradiation volumes, there is always the danger of overdosage or underdosage with the familiar consequences. Four targeting systems in one plane were inserted in a perspex frame each consisting of two concentric rings and two orthogonal crossbars. Under simulation conditions, the lateral radiation fields take up one half of the targeting systems and the ventro-dorsal fields occupy the remaining half. The corresponding targeting systems project exactly on or into each other with compensation of the beam divergence. A definitively exact irradiation via cranio-caudally contiguous fields with different incident beam direction is possible by using the four targeting systems in one plane. Compensation of divergence is aimed for by rotation of the table and gantry angle modification, errors of compensation can already be checked optically from 0,5 . Deviations of 5 mm in the simulated longitudinal arrangement of the contiguous fields can be imaged on the documentation film made with therapy activity. On the one hand, the auxillary system presented allows both recognition of undesired field overlap and gaps in contiguous fields with different incident beam direction. On the other hand, it can be unequivocally documented whether the therapy is correct. Treatment errors can thus be minimized. (orig./MG) [de

Particle creation by black holes

International Nuclear Information System (INIS)

Hawking, S.W.

1975-01-01

In the classical theory black holes can only absorb and not emit particles. However it is shown that quantum mechanical effects cause black holes to create and emit particles. This thermal emission leads to a slow decrease in the mass of the black hole and to its eventual disappearance: any primordial black hole of mass less than about 10 15 g would have evaporated by now. Although these quantum effects violate the classical law that the area of the event horizon of a black hole cannot decrease, there remains a Generalized Second Law: S + 1/4 A never decreases where S is the entropy of matter outside black holes and A is the sum of the surface areas of the event horizons. This shows that gravitational collapse converts the baryons and leptons in the collapsing body into entropy. It is tempting to speculate that this might be the reason why the Universe contains so much entropy per baryon. (orig.) [de

The 2002 Antarctic Ozone Hole

Science.gov (United States)

Newman, P. A.; Nash, E. R.; Douglass, A. R.; Kawa, S. R.

2003-01-01

Since 1979, the ozone hole has grown from near zero size to over 24 Million km2. This area is most strongly controlled by levels of inorganic chlorine and bromine oncentrations. In addition, dynamical variations modulate the size of the ozone hole by either cooling or warming the polar vortex collar region. We will review the size observations, the size trends, and the interannual variability of the size. Using a simple trajectory model, we will demonstrate the sensitivity of the ozone hole to dynamical forcing, and we will use these observations to discuss the size of the ozone hole during the 2002 Austral spring. We will further show how the Cly decreases in the stratosphere will cause the ozone hole to decrease by 1-1.5% per year. We will also show results from a 3-D chemical transport model (CTM) that has been continuously run since 1999. These CTM results directly show how strong dynamics acts to reduce the size of the ozone hole.

Black Hole's 1/N Hair

CERN Document Server

Dvali, Gia

2013-01-01

According to the standard view classically black holes carry no hair, whereas quantum hair is at best exponentially weak. We show that suppression of hair is an artifact of the semi-classical treatment and that in the quantum picture hair appears as an inverse mass-square effect. Such hair is predicted in the microscopic quantum description in which a black hole represents a self-sustained leaky Bose-condensate of N soft gravitons. In this picture the Hawking radiation is the quantum depletion of the condensate. Within this picture we show that quantum black hole physics is fully compatible with continuous global symmetries and that global hair appears with the strength B/N, where B is the global charge swallowed by the black hole. For large charge this hair has dramatic effect on black hole dynamics. Our findings can have interesting astrophysical consequences, such as existence of black holes with large detectable baryonic and leptonic numbers.

Black holes a very short introduction

CERN Document Server

Blundell, Katherine

2015-01-01

Black holes are a constant source of fascination to many due to their mysterious nature. Black Holes: A Very Short Introduction addresses a variety of questions, including what a black hole actually is, how they are characterized and discovered, and what would happen if you came too close to one. It explains how black holes form and grow—by stealing material that belongs to stars—as well as how many there may be in the Universe. It also explores the large black holes found in the centres of galaxies, and how black holes power quasars and lie behind other spectacular phenomena in the cosmos.

Recovering missing data: estimating position and size of caudal vertebrae in Staurikosaurus pricei Colbert, 1970

Directory of Open Access Journals (Sweden)

Orlando N. Grillo

2011-03-01

Full Text Available Missing data is a common problem in paleontology. It makes it difficult to reconstruct extinct taxa accurately and restrains the inclusion of some taxa on comparative and biomechanical studies. Particularly, estimating the position of vertebrae on incomplete series is often non-empirical and does not allow precise estimation of missing parts. In this work we present a method for calculating the position of preserved middle sequences of caudal vertebrae in the saurischian dinosaur Staurikosaurus pricei, based on the length and height of preserved anterior and posterior caudal vertebral centra. Regression equations were used to estimate these dimensions for middle vertebrae and, consequently, to assess the position of the preserved middle sequences. It also allowed estimating these dimensions for non-preserved vertebrae. Results indicate that the preserved caudal vertebrae of Staurikosaurus may correspond to positions 1-3, 5, 7, 14-19/15-20, 24-25/25-26, and 29-47, and that at least 25 vertebrae had transverse processes. Total length of the tail was estimated in 134 cm and total body length was 220-225 cm.Dados lacunares são um problema comum na paleontologia. Eles dificultam a reconstrução acurada de táxons extintos e limitam a inclusão de alguns táxons em estudos comparativose biomecânicos. Particularmente, estimar a posição de vértebras em séries incompletas tem sido feito com base em métodos não empíricos que não permitem estimar corretamente as partes ausentes. Neste trabalho apresentamos uma metodologia que permite estimar a posição de sequências médias preservadas de vértebras caudais no dinossauro saurísquio Staurikosaurus pricei, com base no comprimento e altura dos centros das vértebras anteriores e posteriores preservadas. Equações de regressão foram usadas para estimar essas dimensões para as vértebras médias e, consequentemente, para posicionar as sequências médias preservadas e para estimar o tamanho das

"Iron-Clad" Evidence For Spinning Black Hole

Science.gov (United States)

2003-09-01

Telltale X-rays from iron may reveal if black holes are spinning or not, according to astronomers using NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton Observatory. The gas flows and bizarre gravitational effects observed near stellar black holes are similar to those seen around supermassive black holes. Stellar black holes, in effect, are convenient `scale models' of their much larger cousins. Black holes come in at least two different sizes. Stellar black holes are between five and 20 times the mass of the Sun. At the other end of the size scale, supermassive black holes contain millions or billions times the mass of our Sun. The Milky Way contains both a supermassive black hole at its center, as well as a number of stellar black holes sprinkled throughout the Galaxy. At a press conference at the "Four Years of Chandra" symposium in Huntsville, Ala., Jon Miller of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. discussed recent results on the X-ray spectra, or distribution of X-rays with energy, from the iron atoms in gas around three stellar black holes in the Milky Way. "Discovering the high degree of correspondence between stellar and supermassive black holes is a real breakthrough," said Miller. "Because stellar black holes are smaller, everything happens about a million times faster, so they can be used as a test-bed for theories of how spinning black holes affect the space and matter around them." X-rays from a stellar black hole are produced when gas from a nearby companion star is heated to tens of millions of degrees as it swirls toward the black hole. Iron atoms in this gas produce distinctive X-ray signals that can be used to study the orbits of particles around the black hole. For example, the gravity of a black hole can shift the X-rays to lower energies. "The latest work provides the most precise measurements yet of the X-ray spectra for stellar black holes," said Miller. "These data help rule out

Epiretinal proliferation in lamellar macular holes and full-thickness macular holes: clinical and surgical findings.

Science.gov (United States)

Lai, Tso-Ting; Chen, San-Ni; Yang, Chung-May

2016-04-01

To report the clinical findings and surgical outcomes of lamellar macular holes (LMH) with or without lamellar hole-associated epiretinal proliferation (LHEP), and those of full-thickness macular holes (FTMH) presenting with LHEP. From 2009 to 2013, consecutive cases of surgically treated LMH, and all FTMH cases with LHEP were reviewed, given a follow-up time over 1 year. In the LMH group (43 cases), those with LHEP (19 cases) had significantly thinner bases and larger openings than those without (24 cases). The rate of disrupted IS/OS line was higher in the LHEP subgroup preoperatively (68.4 % vs 37.5 %), but similar between subgroups postoperatively (36.8 % and 33.3 %). The preoperative and postoperative visual acuity showed no significant difference between two subgroups. In the FTMH group (13 cases), the average hole size was 219.2 ± 92.1 μm. Permanent or transient spontaneous hole closure was noted in 69.2 % of cases. An intact IS-OS line was found in only 23 % of cases at the final follow-up. In the LMH group, LHEP was associated with a more severe defect but didn't affect surgical outcomes. In the FTMH group, spontaneous hole closure was frequently noted. Despite small holes, disruption of IS-OS line was common after hole closure.

Nonextremal stringy black hole

International Nuclear Information System (INIS)

Suzuki, K.

1997-01-01

We construct a four-dimensional BPS saturated heterotic string solution from the Taub-NUT solution. It is a nonextremal black hole solution since its Euler number is nonzero. We evaluate its black hole entropy semiclassically. We discuss the relation between the black hole entropy and the degeneracy of string states. The entropy of our string solution can be understood as the microscopic entropy which counts the elementary string states without any complications. copyright 1997 The American Physical Society

Acetylcarnitine metabolism and the partial purification and characterization of an acetylcarnitine hydrolase from bovine caudal epididymal spermatozoa

International Nuclear Information System (INIS)

Bruns, K.A.

1987-01-01

Epididymal spermatozoa are capable of utilizing extracellular substrates for energy, but carbohydrates and free or esterified fatty acids are present in only very low concentrations in epididymal fluid. Acetyl-L-carnitine has been identified in epididymal fluid in low mM concentrations in several mammalian species and could possibly be an energy substrate for epididymal spermatozoa. Evidence that extracellular acetyl-L-carnitine can be used by intact caudal epididymal spermatozoa for energy, and a model for the metabolism of acetyl-L-carnitine by epididymal spermatozoa are presented here. Intact bovine and hamster caudal epididymal spermatozoa oxidized [1- 14 C] acetyl-L-carnitine to 14 CO 2 in a time-, cell number-, and substrate concentration-dependent manner. No concomitant uptake of acetyl-D,L-[N-methyl- 3 H] carnitine was observed by cells from the same preparations. Half-maximal rates of oxidation were observed at 8 mM and 4.5 mM acetyl-L-carnitine for the two species, respectively; the rates of oxidation at these concentrations were 15.3 nmol/10 8 cells·h and 2.9 nmol/10 7 cells·h. Intact spermatozoa in incubation with [ 3 H] acetyl-L-carnitine were observed to produce [ 3 H] acetate in the medium, and addition of sodium acetate competed for the uptake of radioactive acetate by these cells

The search for black holes

International Nuclear Information System (INIS)

Torn, K.

1976-01-01

Conceivable experimental investigations to prove the existence of black holes are discussed. Double system with a black hole turning around a star-satellite are in the spotlight. X-radiation emmited by such systems and resulting from accretion of the stellar gas by a black hole, and the gas heating when falling on the black hole might prove the model suggested. A source of strong X-radiation observed in the Cygnus star cluster and referred to as Cygnus X-1 may be thus identified as a black hole. Direct registration of short X-ray pulses with msec intervals might prove the suggestion. The lack of appropriate astrophysic facilities is pointed out to be the major difficulty on the way of experimental verifications

Stability of squashed Kaluza-Klein black holes

International Nuclear Information System (INIS)

Kimura, Masashi; Ishihara, Hideki; Murata, Keiju; Soda, Jiro

2008-01-01

The stability of squashed Kaluza-Klein black holes is studied. The squashed Kaluza-Klein black hole looks like a five-dimensional black hole in the vicinity of horizon and looks like a four-dimensional Minkowski spacetime with a circle at infinity. In this sense, squashed Kaluza-Klein black holes can be regarded as black holes in the Kaluza-Klein spacetimes. Using the symmetry of squashed Kaluza-Klein black holes, SU(2)xU(1)≅U(2), we obtain master equations for a part of the metric perturbations relevant to the stability. The analysis based on the master equations gives strong evidence for the stability of squashed Kaluza-Klein black holes. Hence, the squashed Kaluza-Klein black holes deserve to be taken seriously as realistic black holes in the Kaluza-Klein spacetime.

Black-hole bomb and superradiant instabilities

International Nuclear Information System (INIS)

Cardoso, Vitor; Dias, Oscar J.C.; Lemos, Jose P.S.; Yoshida, Shijun

2004-01-01

A wave impinging on a Kerr black hole can be amplified as it scatters off the hole if certain conditions are satisfied, giving rise to superradiant scattering. By placing a mirror around the black hole one can make the system unstable. This is the black-hole bomb of Press and Teukolsky. We investigate in detail this process and compute the growing time scales and oscillation frequencies as a function of the mirror's location. It is found that in order for the system black hole plus mirror to become unstable there is a minimum distance at which the mirror must be located. We also give an explicit example showing that such a bomb can be built. In addition, our arguments enable us to justify why large Kerr-AdS black holes are stable and small Kerr-AdS black holes should be unstable

Interior structure of rotating black holes. III. Charged black holes

International Nuclear Information System (INIS)

Hamilton, Andrew J. S.

2011-01-01

This paper extends to the case of charged rotating black holes the conformally stationary, axisymmetric, conformally separable solutions presented for uncharged rotating black holes in a companion paper. In the present paper, the collisionless fluid accreted by the black hole may be charged. The charge of the black hole is determined self-consistently by the charge accretion rate. As in the uncharged case, hyper-relativistic counterstreaming between ingoing and outgoing streams drives inflation at (just above) the inner horizon, followed by collapse. If both ingoing and outgoing streams are charged, then conformal separability holds during early inflation, but fails as inflation develops. If conformal separability is imposed throughout inflation and collapse, then only one of the ingoing and outgoing streams can be charged: the other must be neutral. Conformal separability prescribes a hierarchy of boundary conditions on the ingoing and outgoing streams incident on the inner horizon. The dominant radial boundary conditions require that the incident ingoing and outgoing number densities be uniform with latitude, but the charge per particle must vary with latitude such that the incident charge densities vary in proportion to the radial electric field. The subdominant angular boundary conditions require specific forms of the incident number- and charge-weighted angular motions. If the streams fall freely from outside the horizon, then the prescribed angular conditions can be achieved by the charged stream, but not by the neutral stream. Thus, as in the case of an uncharged black hole, the neutral stream must be considered to be delivered ad hoc to just above the inner horizon.

30 CFR 57.9360 - Shelter holes.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shelter holes. 57.9360 Section 57.9360 Mineral....9360 Shelter holes. (a) Shelter holes shall be— (1) Provided at intervals adequate to assure the safety... farthest projection of moving equipment. (b) Shelter holes shall not be used for storage unless a 40-inch...

Turbulent black holes.

Science.gov (United States)

Yang, Huan; Zimmerman, Aaron; Lehner, Luis

2015-02-27

We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids.

Information Retention by Stringy Black Holes

CERN Document Server

Ellis, John

2015-01-01

Building upon our previous work on two-dimensional stringy black holes and its extension to spherically-symmetric four-dimensional stringy black holes, we show how the latter retain information. A key r\\^ole is played by an infinite-dimensional $W_\\infty$ symmetry that preserves the area of an isolated black-hole horizon and hence its entropy. The exactly-marginal conformal world-sheet operator representing a massless stringy particle interacting with the black hole necessarily includes a contribution from $W_\\infty$ generators in its vertex function. This admixture manifests the transfer of information between the string black hole and external particles. We discuss different manifestations of $W_\\infty$ symmetry in black-hole physics and the connections between them.

Shaping Globular Clusters with Black Holes

Science.gov (United States)

Kohler, Susanna

2018-03-01

How many black holes lurk within the dense environments of globular clusters, and how do these powerful objects shape the properties of the cluster around them? One such cluster, NGC 3201, is now helping us to answer these questions.Hunting Stellar-Mass Black HolesSince the detection of merging black-hole binaries by the Laser Interferometer Gravitational-Wave Observatory (LIGO), the dense environments of globular clusters have received increasing attention as potential birthplaces of these compact binary systems.The central region of the globular star cluster NGC 3201, as viewed by Hubble. The black hole is in orbit with the star marked by the blue circle. [NASA/ESA]In addition, more and more stellar-mass black-hole candidates have been observed within globular clusters, lurking in binary pairs with luminous, non-compact companions. The most recent of these detections, found in the globular cluster NGC 3201, stands alone as the first stellar-mass black hole candidate discovered via radial velocity observations: the black holes main-sequence companion gave away its presence via a telltale wobble.Now a team of scientists led by Kyle Kremer (CIERA and Northwestern University) is using models of this system to better understand the impact that black holes might have on their host clusters.A Model ClusterThe relationship between black holes and their host clusters is complicated. Though the cluster environment can determine the dynamical evolution of the black holes, the retention rate of black holes in a globular cluster (i.e., how many remain in the cluster when they are born as supernovae, rather than being kicked out during the explosion) influences how the host cluster evolves.Kremer and collaborators track this complex relationship by modeling the evolution of a cluster similar to NGC 3201 with a Monte Carlo code. The code incorporates physics relevant to the evolution of black holes and black-hole binaries in globular clusters, such as two-body relaxation

Black holes matter

DEFF Research Database (Denmark)

Kragh, Helge Stjernholm

2016-01-01

Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015).......Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015)....

Newborn Black Holes

Science.gov (United States)

Science Teacher, 2005

2005-01-01

Scientists using NASA's Swift satellite say they have found newborn black holes, just seconds old, in a confused state of existence. The holes are consuming material falling into them while somehow propelling other material away at great speeds. "First comes a blast of gamma rays followed by intense pulses of x-rays. The energies involved are much…

30 CFR 77.1010 - Collaring holes.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Collaring holes. 77.1010 Section 77.1010... Control § 77.1010 Collaring holes. (a) Starter steels shall be used when collaring holes with hand-held drills. (b) Men shall not hold the drill steel while collaring holes, or rest their hands on the chuck or...

Statistical clustering of primordial black holes

Energy Technology Data Exchange (ETDEWEB)

Carr, B J [Cambridge Univ. (UK). Inst. of Astronomy

1977-04-01

It is shown that Meszaros theory of galaxy formation, in which galaxies form from the density perturbations associated with the statistical fluctuation in the number density of primordial black holes, must be modified if the black holes are initially surrounded by regions of lower radiation density than average (as is most likely). However, even in this situation, the sort of effect Meszaros envisages does occur and could in principle cause galactic mass-scales to bind at the conventional time. In fact, the requirement that galaxies should not form prematurely implies that black holes could not have a critical density in the mass range above 10/sup 5/ M(sun). If the mass spectrum of primordial black holes falls off more slowly than m/sup -3/ (as expected), then the biggest black holes have the largest clustering effect. In this case the black hole clustering theory of galaxy formation reduces to the black hole seed theory of galaxy formation, in which each galaxy becomes bound under the gravitational influence of a single black hole nucleus. The seed theory could be viable only if the early Universe had a soft equation of state until a time exceeding 10/sup -4/ s or if something prevented black hole formation before 1 s.

Black holes and quantum processes in them

International Nuclear Information System (INIS)

Frolov, V.P.

1976-01-01

The latest achievements in the physics of black holes are reviewed. The problem of quantum production in a strong gravitational field of black holes is considered. Another parallel discovered during investigation of interactions between black holes and between black holes and surrounding media, is also drawn with thermodynamics. A gravitational field of rotating black holes is considered. Some cosmological aspects of evaporation of small black holes are discussed as well as possibilities to observe them

Black holes and everyday physics

International Nuclear Information System (INIS)

Bekenstein, J.D.

1982-01-01

Black holes have piqued much curiosity. But thus far they have been important only in ''remote'' subjects like astrophysics and quantum gravity. It is shown that the situation can be improved. By a judicious application of black hole physics, one can obtain new results in ''everyday physics''. For example, black holes yield a quantum universal upper bound on the entropy-to-energy ratio for ordinary thermodynamical systems which was unknown earlier. It can be checked, albeit with much labor, by ordinary statistical methods. Black holes set a limitation on the number of species of elementary particles-quarks, leptons, neutrinos - which may exist. And black holes lead to a fundamental limitation on the rate at which information can be transferred for given message energy by any communication system. (author)

Black hole final state conspiracies

International Nuclear Information System (INIS)

McInnes, Brett

2009-01-01

The principle that unitarity must be preserved in all processes, no matter how exotic, has led to deep insights into boundary conditions in cosmology and black hole theory. In the case of black hole evaporation, Horowitz and Maldacena were led to propose that unitarity preservation can be understood in terms of a restriction imposed on the wave function at the singularity. Gottesman and Preskill showed that this natural idea only works if one postulates the presence of 'conspiracies' between systems just inside the event horizon and states at much later times, near the singularity. We argue that some AdS black holes have unusual internal thermodynamics, and that this may permit the required 'conspiracies' if real black holes are described by some kind of sum over all AdS black holes having the same entropy

Black hole shadow in an asymptotically flat, stationary, and axisymmetric spacetime: The Kerr-Newman and rotating regular black holes

Science.gov (United States)

Tsukamoto, Naoki

2018-03-01

The shadow of a black hole can be one of the strong observational evidences for stationary black holes. If we see shadows at the center of galaxies, we would say whether the observed compact objects are black holes. In this paper, we consider a formula for the contour of a shadow in an asymptotically-flat, stationary, and axisymmetric black hole spacetime. We show that the formula is useful for obtaining the contour of the shadow of several black holes such as the Kerr-Newman black hole and rotating regular black holes. Using the formula, we can obtain new examples of the contour of the shadow of rotating black holes if assumptions are satisfied.

K-shell-hole production, multiple-hole production, charge transfer, and antisymmetry

International Nuclear Information System (INIS)

Reading, J.F.; Ford, A.L.

1980-01-01

In calculating K-shell-hole production when an ion collides with an atom, account must be taken of the fact that processes involving electrons other than the K-shell electron can occur. For example, after making a K-shell hole an L-shell electron may be knocked into it, or an L-shell vacancy may be produced and the K-shell electron promoted to that vacancy in the ''Fermi sea'' of the target-atom orbitals. In 1973 a theorem was proved by one of the present authors demonstrating that all these multielectron processes cancel in an independent-particle model for the target atom. In this paper it is shown that the same thing occurs for hole production by charge transfer to the ion. The authors demonstrate that multihole production does not obey this simple rule and that the probability for multihole production is not the product of independent single-electron probabilities. The correct expressions that should be used for these processes are given, together with new results for charge-transfer processes accompanied by hole production

Drilling history core hole DC-4

International Nuclear Information System (INIS)

1978-12-01

Core hole DC-4 was completed at a depth of 3998 feet in December, 1978 by Boyles Brothers Drilling Company, Spokane, Washington, under subcontract to Fenix and Scission, Inc. The hole was cored for the US Department of Energy and the Rockwell Hanford Operations' Basalt Waste Isolation Program. Fenix and Sicsson, Inc. furnished the engineering, daily supervision of the cable tool and core drilling activities, and geological core logging for DC-4. Core hole DC-4 is located on the Hanford Site about 3 miles east of the Yakima Barricade and approximately 103 feet southwest of rotary hole DC-5, which was completed to 3990 feet in February, 1978. Hanford Site coordinates reported for hole DC-4 are north 49,385.62 feet and west 85,207.63 feet, and Washington State coordinates are north 454,468.73 feet and east 2,209,990.87 feet. No elevation survey is available for hole DC-4, but it is approximately 745 feet above mean sea level based upon the survey of hole DC-5, which has a reported elevation of 745.16 feet on the top of the 3-inch flange. The purpose of core hole DC-4 was to core drill vertically through the basalt and interbed units for stratigraphic depth determination and core collection, and to provide a borehole for hydrologic testing, cross-hole seismic shear, and pressure wave velocity studies with rotary hole DC-5. Hole DC-4 was drilled through the overburden into basalt bedrock by cable tool methods (0-623 feet) and continuously cored through the final interval (623 to 3998 feet).Core recovery was 95.8 percent of the total footage cored

Warped products and black holes

International Nuclear Information System (INIS)

Hong, Soon-Tae

2005-01-01

We apply the warped product space-time scheme to the Banados-Teitelboim-Zanelli black holes and the Reissner-Nordstroem-anti-de Sitter black hole to investigate their interior solutions in terms of warped products. It is shown that there exist no discontinuities of the Ricci and Einstein curvatures across event horizons of these black holes

Atomic structure in black hole

International Nuclear Information System (INIS)

Nagatani, Yukinori

2006-01-01

We propose that any black hole has atomic structure in its inside and has no horizon as a model of black holes. Our proposal is founded on a mean field approximation of gravity. The structure of our model consists of a (charged) singularity at the center and quantum fluctuations of fields around the singularity, namely, it is quite similar to that of atoms. Any properties of black holes, e.g. entropy, can be explained by the model. The model naturally quantizes black holes. In particular, we find the minimum black hole, whose structure is similar to that of the hydrogen atom and whose Schwarzschild radius is approximately 1.1287 times the Planck length. Our approach is conceptually similar to Bohr's model of the atomic structure, and the concept of the minimum Schwarzschild radius is similar to that of the Bohr radius. The model predicts that black holes carry baryon number, and the baryon number is rapidly violated. This baryon number violation can be used as verification of the model. (author)

Gamma ray bursts of black hole universe

Science.gov (United States)

Zhang, T. X.

2015-07-01

Slightly modifying the standard big bang theory, Zhang recently developed a new cosmological model called black hole universe, which has only a single postulate but is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain existing observations of the universe. In the previous studies, we have explained the origin, structure, evolution, expansion, cosmic microwave background radiation, quasar, and acceleration of black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This study investigates gamma ray bursts of black hole universe and provides an alternative explanation for the energy and spectrum measurements of gamma ray bursts according to the black hole universe model. The results indicate that gamma ray bursts can be understood as emissions of dynamic star-like black holes. A black hole, when it accretes its star or merges with another black hole, becomes dynamic. A dynamic black hole has a broken event horizon and thus cannot hold the inside hot (or high-frequency) blackbody radiation, which flows or leaks out and produces a GRB. A star when it collapses into its core black hole produces a long GRB and releases the gravitational potential energy of the star as gamma rays. A black hole that merges with another black hole produces a short GRB and releases a part of their blackbody radiation as gamma rays. The amount of energy obtained from the emissions of dynamic star-like black holes are consistent with the measurements of energy from GRBs. The GRB energy spectra derived from this new emission mechanism are also consistent with the measurements.

Simulations of nearly extremal binary black holes

Science.gov (United States)

Giesler, Matthew; Scheel, Mark; Hemberger, Daniel; Lovelace, Geoffrey; Kuper, Kevin; Boyle, Michael; Szilagyi, Bela; Kidder, Lawrence; SXS Collaboration

2015-04-01

Astrophysical black holes could have nearly extremal spins; therefore, nearly extremal black holes could be among the binaries that current and future gravitational-wave observatories will detect. Predicting the gravitational waves emitted by merging black holes requires numerical-relativity simulations, but these simulations are especially challenging when one or both holes have mass m and spin S exceeding the Bowen-York limit of S /m2 = 0 . 93 . Using improved methods we simulate an unequal-mass, precessing binary black hole coalescence, where the larger black hole has S /m2 = 0 . 99 . We also use these methods to simulate a nearly extremal non-precessing binary black hole coalescence, where both black holes have S /m2 = 0 . 994 , nearly reaching the Novikov-Thorne upper bound for holes spun up by thin accretion disks. We demonstrate numerical convergence and estimate the numerical errors of the waveforms; we compare numerical waveforms from our simulations with post-Newtonian and effective-one-body waveforms; and we compare the evolution of the black-hole masses and spins with analytic predictions.

Instability of ultra-spinning black holes

International Nuclear Information System (INIS)

Emparan, Roberto; Myers, Robert C.

2003-01-01

It has long been known that, in higher-dimensional general relativity, there are black hole solutions with an arbitrarily large angular momentum for a fixed mass. We examine the geometry of the event horizon of such ultra-spinning black holes and argue that these solutions become unstable at large enough rotation. Hence we find that higher-dimensional general relativity imposes an effective 'Kerr-bound' on spinning black holes through a dynamical decay mechanism. Our results also give indications of the existence of new stationary black holes with 'rippled' horizons of spherical topology. We consider various scenarios for the possible decay of ultra-spinning black holes, and finally discuss the implications of our results for black holes in braneworld scenarios. (author)

Braneworld black holes and entropy bounds

Directory of Open Access Journals (Sweden)

Y. Heydarzade

2018-01-01

Full Text Available The Bousso's D-bound entropy for the various possible black hole solutions on a 4-dimensional brane is checked. It is found that the D-bound entropy here is apparently different from that of obtained for the 4-dimensional black hole solutions. This difference is interpreted as the extra loss of information, associated to the extra dimension, when an extra-dimensional black hole is moved outward the observer's cosmological horizon. Also, it is discussed that N-bound entropy is hold for the possible solutions here. Finally, by adopting the recent Bohr-like approach to black hole quantum physics for the excited black holes, the obtained results are written also in terms of the black hole excited states.

Black holes new horizons

CERN Document Server

Hayward, Sean Alan

2013-01-01

Black holes, once just fascinating theoretical predictions of how gravity warps space-time according to Einstein's theory, are now generally accepted as astrophysical realities, formed by post-supernova collapse, or as supermassive black holes mysteriously found at the cores of most galaxies, powering active galactic nuclei, the most powerful objects in the universe. Theoretical understanding has progressed in recent decades with a wider realization that local concepts should characterize black holes, rather than the global concepts found in textbooks. In particular, notions such as trapping h

Quantum information erasure inside black holes

International Nuclear Information System (INIS)

Lowe, David A.; Thorlacius, Larus

2015-01-01

An effective field theory for infalling observers in the vicinity of a quasi-static black hole is given in terms of a freely falling lattice discretization. The lattice model successfully reproduces the thermal spectrum of outgoing Hawking radiation, as was shown by Corley and Jacobson, but can also be used to model observations made by a typical low-energy observer who enters the black hole in free fall at a prescribed time. The explicit short distance cutoff ensures that, from the viewpoint of the infalling observer, any quantum information that entered the black hole more than a scrambling time earlier has been erased by the black hole singularity. This property, combined with the requirement that outside observers need at least of order the scrambling time to extract quantum information from the black hole, ensures that a typical infalling observer does not encounter drama upon crossing the black hole horizon in a theory where black hole information is preserved for asymptotic observers.

Statistical Hair on Black Holes

International Nuclear Information System (INIS)

Strominger, A.

1996-01-01

The Bekenstein-Hawking entropy for certain BPS-saturated black holes in string theory has recently been derived by counting internal black hole microstates at weak coupling. We argue that the black hole microstate can be measured by interference experiments even in the strong coupling region where there is clearly an event horizon. Extracting information which is naively behind the event horizon is possible due to the existence of statistical quantum hair carried by the black hole. This quantum hair arises from the arbitrarily large number of discrete gauge symmetries present in string theory. copyright 1996 The American Physical Society

On black hole horizon fluctuations

International Nuclear Information System (INIS)

Tuchin, K.L.

1999-01-01

A study of the high angular momentum particles 'atmosphere' near the Schwarzschild black hole horizon suggested that strong gravitational interactions occur at invariant distance of the order of 3 √M [2]. We present a generalization of this result to the Kerr-Newman black hole case. It is shown that the larger charge and angular momentum black hole bears, the larger invariant distance at which strong gravitational interactions occur becomes. This invariant distance is of order 3 √((r + 2 )/((r + - r - ))). This implies that the Planckian structure of the Hawking radiation of extreme black holes is completely broken

Thermodynamics of Accelerating Black Holes.

Science.gov (United States)

Appels, Michael; Gregory, Ruth; Kubizňák, David

2016-09-23

We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon-even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.

C8 cross transfer for the treatment of caudal brachial plexus avulsion in three dogs.

Science.gov (United States)

Moissonnier, Pierre; Carozzo, Claude; Thibaut, Jean-Laurent; Escriou, Catherine; Hidalgo, Antoine; Blot, Stéphane

2017-01-01

To evaluate the cervical nerve 8 cross-transfer technique (C8CT) as a part of surgical treatment of caudal brachial plexus avulsion (BPA) in the dog. Case series. Client-owned dogs suspected to have caudal BPA based on neurological examination and electrophysiological testing (n = 3). The distal stump of the surgically transected contralateral C8 ventral branch (donor) was bridged to the proximal stump of the avulsed C8 ventral branch (recipient) and secured with 9-0 polypropylene suture under an operating microscope. A carpal panarthrodesis was performed on the injured limb after C8CT. Surgical exploration confirmed avulsion of nerve roots C7, C8, and T1 in all cases. There was no evidence of an iatrogenic effect on the donor forelimb. Gradual improvement in function of the affected forelimb occurred in all dogs, with eventual recovery of voluntary elbow extension. Reinnervation was evident in EMG recordings 6 months postoperatively in all three dogs. Stimulation of the donor C8 ventral branch led to motor evoked potentials in the avulsed side triceps brachialis and radial carpus extensor muscles. Variable functional outcome was observed in the 3 dogs during clinical evaluation 3-4 years after surgery. Digital abrasion wounds, distal interphalangeal infectious arthritis, and self-mutilation necessitated distal phalanx amputation of digits 3 and 4 in 2 dogs. C8CT provided partial reconnection of the donor C8 ventral branch to the avulsed brachial plexus in the 3 dogs of this series. Reinnervation resulted in active elbow extension and promoted functional recovery in the affected limb. © 2017 The American College of Veterinary Surgeons.

Conserved size and periodicity of pyramidal patches in layer 2 of medial/caudal entorhinal cortex.

Science.gov (United States)

Naumann, Robert K; Ray, Saikat; Prokop, Stefan; Las, Liora; Heppner, Frank L; Brecht, Michael

2016-03-01

To understand the structural basis of grid cell activity, we compare medial entorhinal cortex architecture in layer 2 across five mammalian species (Etruscan shrews, mice, rats, Egyptian fruit bats, and humans), bridging ∼100 million years of evolutionary diversity. Principal neurons in layer 2 are divided into two distinct cell types, pyramidal and stellate, based on morphology, immunoreactivity, and functional properties. We confirm the existence of patches of calbindin-positive pyramidal cells across these species, arranged periodically according to analyses techniques like spatial autocorrelation, grid scores, and modifiable areal unit analysis. In rodents, which show sustained theta oscillations in entorhinal cortex, cholinergic innervation targeted calbindin patches. In bats and humans, which only show intermittent entorhinal theta activity, cholinergic innervation avoided calbindin patches. The organization of calbindin-negative and calbindin-positive cells showed marked differences in entorhinal subregions of the human brain. Layer 2 of the rodent medial and the human caudal entorhinal cortex were structurally similar in that in both species patches of calbindin-positive pyramidal cells were superimposed on scattered stellate cells. The number of calbindin-positive neurons in a patch increased from ∼80 in Etruscan shrews to ∼800 in humans, only an ∼10-fold over a 20,000-fold difference in brain size. The relatively constant size of calbindin patches differs from cortical modules such as barrels, which scale with brain size. Thus, selective pressure appears to conserve the distribution of stellate and pyramidal cells, periodic arrangement of calbindin patches, and relatively constant neuron number in calbindin patches in medial/caudal entorhinal cortex. © 2015 The Authors. The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.

COMPARATIVE STUDY TO EVALUATE ANALGESIC EFFICACY OF CAUDAL MIDAZOLAM AND CLONIDINE POSTOPERATIVE ANALGESIA IN CHILDREN

Directory of Open Access Journals (Sweden)

Ramalinga Raju A.V.S

2017-03-01

Full Text Available BACKGROUND Caudal epidural analgesia is one of the most popular regional techniques used in paediatric patients undergoing lower limb, anoperineal and abdominal surgical procedures for postoperative pain relief. The aim of postoperative pain relief is to provide subjective comfort and inhibit trauma-induced nociceptive impulses to blunt autonomic and reflex responses to pain and subsequently to enhance the restoration of function. Caudal epidural analgesia though practiced widely is of short duration even when used with long-acting local anaesthetics. MATERIALS AND METHODS Children of either sex undergoing elective hernia or hydrocele surgery within in the age group of 2-8 years belonging to ASA I and II were included in the study. Informed consent was obtained from the parents before procedure. RESULTS The duration of analgesia in the study group was 10.14 ± 4.69 hrs. and 6.83 ± 0.79 hrs. in the clonidine group and midazolam group. Duration of analgesia in clonidine group was significantly longer when compared to with midazolam group with a p value of <0.05. Sedation Score- There was decrease in heart rate and mean arterial pressure from baseline, but these were under allowable limits of 20%. The patient had pain scores of less than 8 for first 6-8 hrs. The patients were well sedated and were easily arousable. CONCLUSION We conclude that in our study we found that clonidine 8 μg/kg provided good analgesia for a longer duration when compared with midazolam. Clonidine also provided good sedation with minimal haemodynamic variations. This is in agreement with studies conducted to know haemodynamic stability with higher doses of clonidine.

Geometry of higher-dimensional black hole thermodynamics

International Nuclear Information System (INIS)

Aaman, Jan E.; Pidokrajt, Narit

2006-01-01

We investigate thermodynamic curvatures of the Kerr and Reissner-Nordstroem (RN) black holes in spacetime dimensions higher than four. These black holes possess thermodynamic geometries similar to those in four-dimensional spacetime. The thermodynamic geometries are the Ruppeiner geometry and the conformally related Weinhold geometry. The Ruppeiner geometry for a d=5 Kerr black hole is curved and divergent in the extremal limit. For a d≥6 Kerr black hole there is no extremality but the Ruppeiner curvature diverges where one suspects that the black hole becomes unstable. The Weinhold geometry of the Kerr black hole in arbitrary dimension is a flat geometry. For the RN black hole the Ruppeiner geometry is flat in all spacetime dimensions, whereas its Weinhold geometry is curved. In d≥5 the Kerr black hole can possess more than one angular momentum. Finally we discuss the Ruppeiner geometry for the Kerr black hole in d=5 with double angular momenta

Functional anatomy of the caudal thoracolumbar and lumbosacral spine in the horse.

Science.gov (United States)

Stubbs, N C; Hodges, P W; Jeffcott, L B; Cowin, G; Hodgson, D R; McGowan, C M

2006-08-01

Research in spinal biomechanics and functional anatomy has advanced back pain research in man. Yet, despite the performance limiting nature of back pain in horses, there are few data for the equine spine. To describe aspects of functional anatomy of the equine thoracolumbar and lumbosacral (LS) spine and potential effects on performance. The first study investigated variations in LS vertebral formula by post mortem examination of 120 horses. Midline vertebral transection was carried out on 65 Thoroughbred (TB), 24 Standardbred (SB) and 31 other breeds. The second study investigated morphology and biomechanics of the deep stabilising epaxial muscles of 13 horses using MRI (n = 3), anatomical dissection (n = 11) and biomechanical analysis (n = 6). The spinous process angular orientation relative to the vertebral body, was analysed at vertebrae T13, T18, L3, L5, L6 and S1. LS variations were found in 33.3% of the total group, 40.0% TB and 45.2% others, but 0% SB. Sacralisation of lumbar vertebra (L) 6 with LS motion between L5 and L6 occurred in 32.3% TB and 29.0% others. Five segmental multifidus fascicles were identified originating from spinous processes and vertebral laminae running craniocaudally onto the mammillary processes and lateral border of the sacrum, crossing between 1-5 intervertebral discs. Sacrocaudalis dorsalis (SCD) lateralis muscle was an extension of multifidus from L4, L5 and L6 depending on the vertebral formula whereas SCD medialis mm originated from S3. Both inserted on caudal vertebrae. Based on the location and direction of fibres, the principal action of the deep epaxial muscles was dorsoventral sagittal rotation. This action was dependent on vertebral spinous process/body orientation. We hypothesise that equine multifidus and SCD lateralis muscles act as caudal sagittal rotators of their vertebra of origin, as is the case in man, allowing dynamic stabilisation during dorsoventral motion. Equine multifidus anatomy and function are

Compressibility of rotating black holes

International Nuclear Information System (INIS)

Dolan, Brian P.

2011-01-01

Interpreting the cosmological constant as a pressure, whose thermodynamically conjugate variable is a volume, modifies the first law of black hole thermodynamics. Properties of the resulting thermodynamic volume are investigated: the compressibility and the speed of sound of the black hole are derived in the case of nonpositive cosmological constant. The adiabatic compressibility vanishes for a nonrotating black hole and is maximal in the extremal case--comparable with, but still less than, that of a cold neutron star. A speed of sound v s is associated with the adiabatic compressibility, which is equal to c for a nonrotating black hole and decreases as the angular momentum is increased. An extremal black hole has v s 2 =0.9 c 2 when the cosmological constant vanishes, and more generally v s is bounded below by c/√(2).

Black holes with halos

Science.gov (United States)

Monten, Ruben; Toldo, Chiara

2018-02-01

We present new AdS4 black hole solutions in N =2 gauged supergravity coupled to vector and hypermultiplets. We focus on a particular consistent truncation of M-theory on the homogeneous Sasaki–Einstein seven-manifold M 111, characterized by the presence of one Betti vector multiplet. We numerically construct static and spherically symmetric black holes with electric and magnetic charges, corresponding to M2 and M5 branes wrapping non-contractible cycles of the internal manifold. The novel feature characterizing these nonzero temperature configurations is the presence of a massive vector field halo. Moreover, we verify the first law of black hole mechanics and we study the thermodynamics in the canonical ensemble. We analyze the behavior of the massive vector field condensate across the small-large black hole phase transition and we interpret the process in the dual field theory.

Black hole as a wormhole factory

Directory of Open Access Journals (Sweden)

Sung-Won Kim

2015-12-01

Full Text Available There have been lots of debates about the final fate of an evaporating black hole and the singularity hidden by an event horizon in quantum gravity. However, on general grounds, one may argue that a black hole stops radiation at the Planck mass (ħc/G1/2∼10−5 g, where the radiated energy is comparable to the black hole's mass. And also, it has been argued that there would be a wormhole-like structure, known as “spacetime foam”, due to large fluctuations below the Planck length (ħG/c31/2∼10−33 cm. In this paper, as an explicit example, we consider an exact classical solution which represents nicely those two properties in a recently proposed quantum gravity model based on different scaling dimensions between space and time coordinates. The solution, called “Black Wormhole”, consists of two different states, depending on its mass parameter M and an IR parameter ω: For the black hole state (with ωM2>1/2, a non-traversable wormhole occupies the interior region of the black hole around the singularity at the origin, whereas for the wormhole state (with ωM2<1/2, the interior wormhole is exposed to an outside observer as the black hole horizon is disappearing from evaporation. The black hole state becomes thermodynamically stable as it approaches the merging point where the interior wormhole throat and the black hole horizon merges, and the Hawking temperature vanishes at the exact merge point (with ωM2=1/2. This solution suggests the “Generalized Cosmic Censorship” by the existence of a wormhole-like structure which protects the naked singularity even after the black hole evaporation. One could understand the would-be wormhole inside the black hole horizon as the result of microscopic wormholes created by “negative” energy quanta which have entered the black hole horizon in Hawking radiation process; the quantum black hole could be a wormhole factory! It is found that this speculative picture may be consistent with the

Black-hole creation in quantum cosmology

Energy Technology Data Exchange (ETDEWEB)

Zhong Chao, Wu [Rome, Univ. `La Sapienza` (Italy). International Center for Relativistic Astrophysics]|[Specola Vaticana, Vatican City State (Vatican City State, Holy See)

1997-11-01

It is proven that the probability of a black hole created from the de Sitter space-time background, at the Wkb level, is the exponential of one quarter of the sum of the black hole and cosmological horizon areas, or the total entropy of the universe. This is true not only for the spherically symmetric cases of the Schwarzschild or Reissner-Nordstroem black holes, but also for the rotating cases of the Kerr black hole and the rotating charged case of the Newman black hole. The de Sitter metric is the most probable evolution at the Planckian era of the universe.

Black Holes in Higher Dimensions

Directory of Open Access Journals (Sweden)

Reall Harvey S.

2008-09-01

Full Text Available We review black-hole solutions of higher-dimensional vacuum gravity and higher-dimensional supergravity theories. The discussion of vacuum gravity is pedagogical, with detailed reviews of Myers–Perry solutions, black rings, and solution-generating techniques. We discuss black-hole solutions of maximal supergravity theories, including black holes in anti-de Sitter space. General results and open problems are discussed throughout.

Sirenomelia: a review of embryogenic theories and discussion of the differences from caudal regression syndrome.

Science.gov (United States)

Isik Kaygusuz, Ecmel; Kurek Eken, Meryem; Sivrikoz, Oya Nermin; Cetiner, Handan

2016-03-01

To discuss the pathological features of sirenomelia in the light of our 10 cases and review the current theories. We identified 10 patients with sirenomelia from our hospital database. All clinical details and the autopsy features of 10 cases were noted. Of the 10 children with sirenomelia seven had bilateral renal agenesis, three had bladder agenesis and one had a renal hypoplasia. Single umbilical artery was found in 60% of children with sirenomelia. External genitalia was ambiguous in seven of 10 patients. Even though the etiology of caudal regression syndrome (CRS) and sirenomelia remains unknown we tend to believe that sirenomelia and CRS might be different entities.

Plasma electron hole kinematics. I. Momentum conservation

Energy Technology Data Exchange (ETDEWEB)

Hutchinson, I. H.; Zhou, C. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2016-08-15

We analyse the kinematic properties of a plasma electron hole: a non-linear self-sustained localized positive electric potential perturbation, trapping electrons, which behaves as a coherent entity. When a hole accelerates or grows in depth, ion and electron plasma momentum is changed both within the hole and outside, by an energization process we call jetting. We present a comprehensive analytic calculation of the momentum changes of an isolated general one-dimensional hole. The conservation of the total momentum gives the hole's kinematics, determining its velocity evolution. Our results explain many features of the behavior of hole speed observed in numerical simulations, including self-acceleration at formation, and hole pushing and trapping by ion streams.

Evolving Coronal Holes and Interplanetary Erupting Stream ...

Indian Academy of Sciences (India)

prominences, have a significantly higher rate of occurrence in the vicinity of coronal .... coronal holes due to the birth of new holes or the growth of existing holes. .... Statistics of newly formed coronal hole areas (NFOCHA) associated with ...

Quantum black holes

OpenAIRE

Hooft, G. 't

1987-01-01

This article is divided into three parts. First, a systematic derivation of the Hawking radiation is given in three different ways. The information loss problem is then discussed in great detail. The last part contains a concise discussion of black hole thermodynamics. This article was published as chapter $6$ of the IOP book "Lectures on General Relativity, Cosmology and Quantum Black Holes" (July $2017$).

Black holes and cosmic censorship

International Nuclear Information System (INIS)

Hiscock, W.A.

1979-01-01

It is widely accepted that the complete gravitational collapse of a body always yields a black hole, and that naked singularities are never produced (the cosmic censorship hypothesis). The local (or strong) cosmic censorship hypothesis states that singularities which are even locally naked (e.g., to an observer inside a black hole) are never produced. This dissertation studies the validity of these two conjectures. The Kerr-Newman metrics describes the black holes only when M 2 greater than or equal to Q 2 + P 2 , where M is the mass of the black hole, a = J/M its specific angular momentum, Q its electric charge, and P its magnetic charge. In the first part of this dissertation, the possibility of converting an extreme Kerr-Newman black hole (M 2 = a 2 + Q 2 + P 2 ) into a naked singularity by the accretion of test particles is considered. The motion of test particles is studied with a large angular momentum to energy ratio, and also test particles with a large charge to energy ratio. The final state is always found to be a black hole if the angular momentum, electric charge, and magnetic charge of the black hole are all much greater than the corresponding angular momentum, electric charge, and magnetic charge of the test particle. In Part II of this dissertation possible black hole interior solutions are studied. The Cauchy horizons and locally naked timelike singularities of the charged (and/or rotating) solutions are contrasted with the spacelike all-encompassing singularity of the Schwarzschild solution. It is determined which portions of the analytic extension of the Reissner-Nordstroem solution are relevant to realistic gravitational collapse

Instability of charged anti-de Sitter black holes

International Nuclear Information System (INIS)

Gwak, Bogeun; Lee, Bum-Hoon; Ro, Daeho

2016-01-01

We have studied the instability of charged anti-de Sitter black holes in four- or higher-dimensions under fragmentation. The unstable black holes under fragmentation can be broken into two black holes. Instability depends not only on the mass and charge of the black hole but also on the ratio between the fragmented black hole and its predecessor. We have found that the near extremal black holes are unstable, and Schwarzschild-AdS black holes are stable. These are qualitatively similar to black holes in four dimensions and higher. The detailed instabilities are numerically investigated.

Spin One Hawking Radiation from Dirty Black Holes

OpenAIRE

Petarpa Boonserm; Tritos Ngampitipan; Matt Visser

2013-01-01

A “clean” black hole is a black hole in vacuum such as the Schwarzschild black hole. However in real physical systems, there are matter fields around a black hole. Such a black hole is called a “dirty black hole”. In this paper, the effect of matter fields on the black hole and the greybody factor is investigated. The results show that matter fields make a black hole smaller. They can increase the potential energy to a black hole to obstruct Hawking radiation to propagate. This causes the gre...

Tracking black holes in numerical relativity

International Nuclear Information System (INIS)

Caveny, Scott A.; Anderson, Matthew; Matzner, Richard A.

2003-01-01

This work addresses the problem of generically tracking black hole event horizons in computational simulation of black hole interactions. Solutions of the hyperbolic eikonal equation, solved on a curved spacetime manifold containing black hole sources, are employed in development of a robust tracking method capable of continuously monitoring arbitrary changes of topology in the event horizon as well as arbitrary numbers of gravitational sources. The method makes use of continuous families of level set viscosity solutions of the eikonal equation with identification of the black hole event horizon obtained by the signature feature of discontinuity formation in the eikonal's solution. The method is employed in the analysis of the event horizon for the asymmetric merger in a binary black hole system. In this first such three dimensional analysis, we establish both qualitative and quantitative evidence for our method and its application to the asymmetric problem. We focus attention on (1) the topology of the throat connecting the holes following merger, (2) the time of merger, and (3) continuing to account for the surface of section areas of the black hole sources

Interface state generation after hole injection

International Nuclear Information System (INIS)

Zhao, C. Z.; Zhang, J. F.; Groeseneken, G.; Degraeve, R.; Ellis, J. N.; Beech, C. D.

2001-01-01

After terminating electrical stresses, the generation of interface states can continue. Our previous work in this area indicates that the interface state generation following hole injection originates from a defect. These defects are inactive in a fresh device, but can be excited by hole injection and then converted into interface states under a positive gate bias after hole injection. There is little information available on these defects. This article investigates how they are formed and attempts to explain why they are sensitive to processing conditions. Roles played by hydrogen and trapped holes will be clarified. A detailed comparison between the interface state generation after hole injection in air and that in forming gas is carried out. Our results show that there are two independent processes for the generation: one is caused by H 2 cracking and the other is not. The rate limiting process for the interface state generation after hole injection is discussed and the relation between the defects responsible for this generation and hole traps is explored. [copyright] 2001 American Institute of Physics

Testing quantum gravity through dumb holes

Energy Technology Data Exchange (ETDEWEB)

Pourhassan, Behnam, E-mail: b.pourhassan@du.ac.ir [School of Physics, Damghan University, Damghan (Iran, Islamic Republic of); Faizal, Mir, E-mail: f2mir@uwaterloo.ca [Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB T1K 3M4 (Canada); Irving K. Barber School of Arts and Sciences, University of British Columbia - Okanagan, Kelowna, BC V1V 1V7 (Canada); Capozziello, Salvatore, E-mail: capozzie@na.infn.it [Dipartimento di Fisica, Università di Napoli ”Frederico II” Complesso Universitario di Monte S. Angelo, Edificio G, Via Cinthia, I-80126 Napoli (Italy); Gran Sasso Science Institute (INFN), Via F. Crispi 7, I-67100 L’ Aquila (Italy)

2017-02-15

We propose a method to test the effects of quantum fluctuations on black holes by analyzing the effects of thermal fluctuations on dumb holes, the analogs for black holes. The proposal is based on the Jacobson formalism, where the Einstein field equations are viewed as thermodynamical relations, and so the quantum fluctuations are generated from the thermal fluctuations. It is well known that all approaches to quantum gravity generate logarithmic corrections to the entropy of a black hole and the coefficient of this term varies according to the different approaches to the quantum gravity. It is possible to demonstrate that such logarithmic terms are also generated from thermal fluctuations in dumb holes. In this paper, we claim that it is possible to experimentally test such corrections for dumb holes, and also obtain the correct coefficient for them. This fact can then be used to predict the effects of quantum fluctuations on realistic black holes, and so it can also be used, in principle, to experimentally test the different approaches to quantum gravity.

Black Hole Paradoxes

International Nuclear Information System (INIS)

Joshi, Pankaj S.; Narayan, Ramesh

2016-01-01

We propose here that the well-known black hole paradoxes such as the information loss and teleological nature of the event horizon are restricted to a particular idealized case, which is the homogeneous dust collapse model. In this case, the event horizon, which defines the boundary of the black hole, forms initially, and the singularity in the interior of the black hole at a later time. We show that, in contrast, gravitational collapse from physically more realistic initial conditions typically leads to the scenario in which the event horizon and space-time singularity form simultaneously. We point out that this apparently simple modification can mitigate the causality and teleological paradoxes, and also lends support to two recently suggested solutions to the information paradox, namely, the ‘firewall’ and ‘classical chaos’ proposals. (paper)

Merging Black Holes

Science.gov (United States)

Centrella, Joan

2012-01-01

The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics

BOOK REVIEW: Introduction to Black Hole Physics Introduction to Black Hole Physics

Science.gov (United States)

Tanaka, Takahiro

2012-07-01

Introduction to Black Hole Physics is a large volume (504 pages), and yet despite this it is still really an introductory text. The book gives an introduction to general relativity, but most of the text is dedicated to attracting the reader's attention to the interesting world of black hole physics. In this sense, the book is very distinct from other textbooks on general relativity. We are told that it was based on the lectures given by Professor Frolov, one of the authors, over the last 30 years. One can obtain the basic ideas about black holes, and also the necessary tips to understand general relativity at a very basic level. For example, in the discussion about particle motion in curved space, the authors start with a brief review on analytical mechanics. The book does not require its readers to have a great deal of knowledge in advance. If you are familiar with such a basic subject, you can simply omit that section. The reason why I especially picked up on this topic as an example is that the book devotes a significant number of pages to geodesic motions in black hole spacetime. One of the main motivations to study black holes is related to how they will actually be observed, once we develop the ability to observe them clearly. The book does explain such discoveries as, for instance, how the motion of a particle is related to a beautiful mathematical structure arising from the hidden symmetry of spacetime, which became transparent via the recent progress in the exploration of black holes in higher dimensions; a concise introduction to this latest topic is deferred to Appendix D, so as not to distract the reader with its mathematical complexities. It should be also mentioned that the book is not limited to general relativistic aspects: quantum fields on a black hole background and Hawking radiation are also covered. Also included are current hot topics, for instance the gravitational waves from a system including black holes, whose first direct detection is

Magnetohydrodynamics near a black hole

International Nuclear Information System (INIS)

Wilson, J.R.

1975-01-01

A numerical computer study of hydromagnetic flow near a black hole is presented. First, the equations of motion are developed to a form suitable for numerical computations. Second, the results of calculations describing the magnetic torques exerted by a rotating black hole on a surrounding magnetic plasma and the electric charge that is induced on the surface of the black hole are presented. (auth)

What is a black hole

International Nuclear Information System (INIS)

Tipler, F.J.

1979-01-01

A definition of a black hole is proposed that should work in any stably causal space-time. This is that a black hole is the closure of the smaller future set that contains all noncosmological trapped surfaces and which has its boundary generated by null geodesic segments that are boundary generators of TIPs. This allows precise definitions of cosmic censorship and white holes. (UK)

Black holes escaping from domain walls

International Nuclear Information System (INIS)

Flachi, Antonino; Sasaki, Misao; Pujolas, Oriol; Tanaka, Takahiro

2006-01-01

Previous studies concerning the interaction of branes and black holes suggested that a small black hole intersecting a brane may escape via a mechanism of reconnection. Here we consider this problem by studying the interaction of a small black hole and a domain wall composed of a scalar field and simulate the evolution of this system when the black hole acquires an initial recoil velocity. We test and confirm previous results, however, unlike the cases previously studied, in the more general set-up considered here, we are able to follow the evolution of the system also during the separation, and completely illustrate how the escape of the black hole takes place

Black Holes Have Simple Feeding Habits

Science.gov (United States)

2008-06-01

The biggest black holes may feed just like the smallest ones, according to data from NASA’s Chandra X-ray Observatory and ground-based telescopes. This discovery supports the implication of Einstein's relativity theory that black holes of all sizes have similar properties, and will be useful for predicting the properties of a conjectured new class of black holes. The conclusion comes from a large observing campaign of the spiral galaxy M81, which is about 12 million light years from Earth. In the center of M81 is a black hole that is about 70 million times more massive than the Sun, and generates energy and radiation as it pulls gas in the central region of the galaxy inwards at high speed. In contrast, so-called stellar mass black holes, which have about 10 times more mass than the Sun, have a different source of food. These smaller black holes acquire new material by pulling gas from an orbiting companion star. Because the bigger and smaller black holes are found in different environments with different sources of material to feed from, a question has remained about whether they feed in the same way. Using these new observations and a detailed theoretical model, a research team compared the properties of M81's black hole with those of stellar mass black holes. The results show that either big or little, black holes indeed appear to eat similarly to each other, and produce a similar distribution of X-rays, optical and radio light. AnimationMulti-wavelength Images of M81 One of the implications of Einstein's theory of General Relativity is that black holes are simple objects and only their masses and spins determine their effect on space-time. The latest research indicates that this simplicity manifests itself in spite of complicated environmental effects. "This confirms that the feeding patterns for black holes of different sizes can be very similar," said Sera Markoff of the Astronomical Institute, University of Amsterdam in the Netherlands, who led the study

Entropy of black holes with multiple horizons

Science.gov (United States)

He, Yun; Ma, Meng-Sen; Zhao, Ren

2018-05-01

We examine the entropy of black holes in de Sitter space and black holes surrounded by quintessence. These black holes have multiple horizons, including at least the black hole event horizon and a horizon outside it (cosmological horizon for de Sitter black holes and "quintessence horizon" for the black holes surrounded by quintessence). Based on the consideration that the two horizons are not independent each other, we conjecture that the total entropy of these black holes should not be simply the sum of entropies of the two horizons, but should have an extra term coming from the correlations between the two horizons. Different from our previous works, in this paper we consider the cosmological constant as the variable and employ an effective method to derive the explicit form of the entropy. We also try to discuss the thermodynamic stabilities of these black holes according to the entropy and the effective temperature.

Black hole entropy, curved space and monsters

International Nuclear Information System (INIS)

Hsu, Stephen D.H.; Reeb, David

2008-01-01

We investigate the microscopic origin of black hole entropy, in particular the gap between the maximum entropy of ordinary matter and that of black holes. Using curved space, we construct configurations with entropy greater than the area A of a black hole of equal mass. These configurations have pathological properties and we refer to them as monsters. When monsters are excluded we recover the entropy bound on ordinary matter S 3/4 . This bound implies that essentially all of the microstates of a semiclassical black hole are associated with the growth of a slightly smaller black hole which absorbs some additional energy. Our results suggest that the area entropy of black holes is the logarithm of the number of distinct ways in which one can form the black hole from ordinary matter and smaller black holes, but only after the exclusion of monster states

Bosonic instability of charged black holes

International Nuclear Information System (INIS)

Gaina, A.B.; Ternov, I.M.

1986-01-01

The processes of spontaneous and induced production and accumulation of charged bosons on quasibound superradiant levels in the field of Kerr-Newman black hole is analysed. It is shown that bosonic instability may be caused exclusively by the rotation of the black hole. Particulary, the Reissner-Nordstrom configuration is stable. In the case of rotating and charged black hole the bosonic instability may cause an increase of charge of the black hole

Measuring the spins of accreting black holes

International Nuclear Information System (INIS)

McClintock, Jeffrey E; Narayan, Ramesh; Gou, Lijun; Kulkarni, Akshay; Penna, Robert F; Steiner, James F; Davis, Shane W; Orosz, Jerome A; Remillard, Ronald A

2011-01-01

A typical galaxy is thought to contain tens of millions of stellar-mass black holes, the collapsed remnants of once massive stars, and a single nuclear supermassive black hole. Both classes of black holes accrete gas from their environments. The accreting gas forms a flattened orbiting structure known as an accretion disk. During the past several years, it has become possible to obtain measurements of the spins of the two classes of black holes by modeling the x-ray emission from their accretion disks. Two methods are employed, both of which depend upon identifying the inner radius of the accretion disk with the innermost stable circular orbit, whose radius depends only on the mass and spin of the black hole. In the Fe Kα method, which applies to both classes of black holes, one models the profile of the relativistically broadened iron line with a special focus on the gravitationally redshifted red wing of the line. In the continuum-fitting (CF) method, which has so far only been applied to stellar-mass black holes, one models the thermal x-ray continuum spectrum of the accretion disk. We discuss both methods, with a strong emphasis on the CF method and its application to stellar-mass black holes. Spin results for eight stellar-mass black holes are summarized. These data are used to argue that the high spins of at least some of these black holes are natal, and that the presence or absence of relativistic jets in accreting black holes is not entirely determined by the spin of the black hole.

Antagonism between the transcription factors NANOG and OTX2 specifies rostral or caudal cell fate during neural patterning transition.

Science.gov (United States)

Su, Zhenghui; Zhang, Yanqi; Liao, Baojian; Zhong, Xiaofen; Chen, Xin; Wang, Haitao; Guo, Yiping; Shan, Yongli; Wang, Lihui; Pan, Guangjin

2018-03-23

During neurogenesis, neural patterning is a critical step during which neural progenitor cells differentiate into neurons with distinct functions. However, the molecular determinants that regulate neural patterning remain poorly understood. Here we optimized the "dual SMAD inhibition" method to specifically promote differentiation of human pluripotent stem cells (hPSCs) into forebrain and hindbrain neural progenitor cells along the rostral-caudal axis. We report that neural patterning determination occurs at the very early stage in this differentiation. Undifferentiated hPSCs expressed basal levels of the transcription factor orthodenticle homeobox 2 (OTX2) that dominantly drove hPSCs into the "default" rostral fate at the beginning of differentiation. Inhibition of glycogen synthase kinase 3β (GSK3β) through CHIR99021 application sustained transient expression of the transcription factor NANOG at early differentiation stages through Wnt signaling. Wnt signaling and NANOG antagonized OTX2 and, in the later stages of differentiation, switched the default rostral cell fate to the caudal one. Our findings have uncovered a mutual antagonism between NANOG and OTX2 underlying cell fate decisions during neural patterning, critical for the regulation of early neural development in humans. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

Black holes at neutrino telescopes

International Nuclear Information System (INIS)

Kowalski, M.; Ringwald, A.; Tu, H.

2002-01-01

In scenarios with extra dimensions and TeV-scale quantum gravity, black holes are expected to be produced in the collision of light particles at center-of-mass energies above the fundamental Planck scale with small impact parameters. Black hole production and evaporation may thus be studied in detail at the large hadron collider (LHC). But even before the LHC starts operating, neutrino telescopes such as AMANDA/IceCube, ANTARES, Baikal, and RICE have an opportunity to search for black hole signatures. Black hole production in the scattering of ultrahigh energy cosmic neutrinos on nucleons in the ice or water may initiate cascades and through-going muons with distinct characteristics above the Standard Model rate. In this Letter, we investigate the sensitivity of neutrino telescopes to black hole production and compare it to the one expected at the Pierre Auger Observatory, an air shower array currently under construction, and at the LHC. We find that, already with the currently available data, AMANDA and RICE should be able to place sensible constraints in black hole production parameter space, which are competitive with the present ones from the air shower facilities Fly's Eye and AGASA. In the optimistic case that a ultrahigh energy cosmic neutrino flux significantly higher than the one expected from cosmic ray interactions with the cosmic microwave background radiation is realized in nature, one even has discovery potential for black holes at neutrino telescopes beyond the reach of LHC. (orig.)

Formation and Coalescence of Electron Solitary Holes

DEFF Research Database (Denmark)

Saeki, K.; Michelsen, Poul; Pécseli, H. L.

1979-01-01

Electron solitary holes were observed in a magnetized collisionless plasma. These holes were identified as Bernstein-Green-Kruskal equilibria, thus being purely kinetic phenomena. The electron hole does not damp even though its velocity is close to the electron thermal velocity. Two holes attract...

Notes on Phase Transition of Nonsingular Black Hole

International Nuclear Information System (INIS)

Ma Meng-Sen; Zhao Ren

2015-01-01

On the belief that a black hole is a thermodynamic system, we study the phase transition of nonsingular black holes. If the black hole entropy takes the form of the Bekenstein—Hawking area law, the black hole mass M is no longer the internal energy of the black hole thermodynamic system. Using the thermodynamic quantities, we calculate the heat capacity, thermodynamic curvature and free energy. It is shown that there will be a larger black hole/smaller black hole phase transition for the nonsingular black hole. At the critical point, the second-order phase transition appears. (paper)

Sizes of Black Holes Throughout the Universe

Science.gov (United States)

Kohler, Susanna

2018-05-01

What is the distribution of sizes of black holes in our universe? Can black holes of any mass exist, or are there gaps in their possible sizes? The shape of this black-hole mass function has been debated for decades and the dawn of gravitational-wave astronomy has only spurred further questions.Mind the GapsThe starting point for the black-hole mass function lies in the initial mass function (IMF) for stellar black holes the beginning size distribution of black holes after they are born from stars. Instead of allowing for the formation of stellar black holes of any mass, theoretical models propose two gaps in the black-hole IMF:An upper mass gap at 50130 solar masses, due to the fact that stellar progenitors of black holes in this mass range are destroyed by pair-instability supernovae.A lower mass gap below 5 solar masses, which is argued to arise naturally from the mechanics of supernova explosions.Missing black-hole (BH) formation channels due to the existence of the lower gap (LG) and the upper gap (UG) in the initial mass function. a) The number of BHs at all scales are lowered because no BH can merge with BHs in the LG to form a larger BH. b) The missing channel responsible for the break at 10 solar masses, resulting from the LG. c) The missing channel responsible for the break at 60 solar masses, due to the interaction between the LG and the UG. [Christian et al. 2018]We can estimate the IMF for black holes by scaling a typical IMF for stars and then adding in these theorized gaps. But is this initial distribution of black-hole masses the same as the distribution that we observe in the universe today?The Influence of MergersBased on recent events, the answer appears to be no! Since the first detections of gravitational waves in September 2015, we now know that black holes can merge to form bigger black holes. An initial distribution of black-hole masses must therefore evolve over time, as mergers cause the depletion of low-mass black holes and an increase in

Lectures on Black Hole Quantum Mechanics

Science.gov (United States)

Wilczek, Frank

The lectures that follow were originally given in 1992, and written up only slightly later. Since then there have been dramatic developments in the quantum theory of black holes, especially in the context of string theory. None of these are reflected here. The concept of quantum hair, which is discussed at length in the lectures, is certainly of permanent interest, and I continue to believe that in some generalized form it will prove central to the whole question of how information is stored in black holes. The discussion of scattering and emission modes from various classes of black holes could be substantially simplified using modern techniques, and from currently popular perspectives the choice of examples might look eccentric. On the other hand fashions have changed rapidly in the field, and the big questions as stated and addressed here, especially as formulated for "real" black holes (nonextremal, in four-dimensional, asymptotically flat space-time, with supersymmetry broken), remain pertinent even as the tools to address them may evolve. The four lectures I gave at the school were based on two lengthy papers that have now been published, "Black Holes as Elementary Particles," Nuclear Physics B380, 447 (1992) and "Quantum Hair on Black Holes," Nuclear Physics B378, 175 (1992). The unifying theme of this work is to help make plausible the possibility that black holes, although they are certainly unusual and extreme states of matter, may be susceptible to a description using concepts that are not fundamentally different from those we use in describing other sorts of quantum-mechanical matter. In the first two lectures I discussed dilaton black holes. The fact that apparently innocuous changes in the "matter" action can drastically change the properties of a black hole is already very significant: it indicates that the physical properties of small black holes cannot be discussed reliably in the abstract, but must be considered with due regard to the rest of

Black-Hole Mass Measurements

DEFF Research Database (Denmark)

Vestergaard, Marianne

2004-01-01

The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized.......The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized....

1 ORIGINAL ARTICLE

African Journals Online (AJOL)

boaz

Bacteriocins produce localized holes in cell wall and cellular membrane ... regeneration of damaged tissues (22). The possibility .... line caudally from the lower margin of the ear. Antisepsis of the ..... the ability to inhibit the growth of the some.

Accretion, primordial black holes and standard cosmology

Indian Academy of Sciences (India)

Primordial black holes evaporate due to Hawking radiation. We find that the evaporation times of primordial black holes increase when accretion of radiation is included. Thus, depending on accretion efficiency, more primordial black holes are existing today, which strengthens the conjecture that the primordial black holes ...

Methodology and consistency of slant and vertical assessments for ionospheric electron content models

Science.gov (United States)

Hernández-Pajares, Manuel; Roma-Dollase, David; Krankowski, Andrzej; García-Rigo, Alberto; Orús-Pérez, Raül

2017-12-01

A summary of the main concepts on global ionospheric map(s) [hereinafter GIM(s)] of vertical total electron content (VTEC), with special emphasis on their assessment, is presented in this paper. It is based on the experience accumulated during almost two decades of collaborative work in the context of the international global navigation satellite systems (GNSS) service (IGS) ionosphere working group. A representative comparison of the two main assessments of ionospheric electron content models (VTEC-altimeter and difference of Slant TEC, based on independent global positioning system data GPS, dSTEC-GPS) is performed. It is based on 26 GPS receivers worldwide distributed and mostly placed on islands, from the last quarter of 2010 to the end of 2016. The consistency between dSTEC-GPS and VTEC-altimeter assessments for one of the most accurate IGS GIMs (the tomographic-kriging GIM `UQRG' computed by UPC) is shown. Typical error RMS values of 2 TECU for VTEC-altimeter and 0.5 TECU for dSTEC-GPS assessments are found. And, as expected by following a simple random model, there is a significant correlation between both RMS and specially relative errors, mainly evident when large enough number of observations per pass is considered. The authors expect that this manuscript will be useful for new analysis contributor centres and in general for the scientific and technical community interested in simple and truly external ways of validating electron content models of the ionosphere.

Articulatory Closure Proficiency in Patients with Parkinson's Disease Following Deep Brain Stimulation of the Subthalamic Nucleus and Caudal Zona Incerta

Science.gov (United States)

Karlsson, Fredrik; Olofsson, Katarina; Blomstedt, Patric; Linder, Jan; Nordh, Erik; van Doorn, Jan

2014-01-01

Purpose: The present study aimed at comparing the effects of deep brain stimulation (DBS) treatment of the subthalamic nucleus (STN) and the caudal zona incerta (cZi) on the proficiency in achieving oral closure and release during plosive production of people with Parkinson's disease. Method: Nineteen patients participated preoperatively and…

Do stringy corrections stabilize colored black holes?

International Nuclear Information System (INIS)

Kanti, P.; Winstanley, E.

2000-01-01

We consider hairy black hole solutions of Einstein-Yang-Mills-dilaton theory, coupled to a Gauss-Bonnet curvature term, and we study their stability under small, spacetime-dependent perturbations. We demonstrate that stringy corrections do not remove the sphaleronic instabilities of colored black holes with the number of unstable modes being equal to the number of nodes of the background gauge function. In the gravitational sector and in the limit of an infinitely large horizon, colored black holes are also found to be unstable. Similar behavior is exhibited by magnetically charged black holes while the bulk of neutral black holes are proved to be stable under small, gauge-dependent perturbations. Finally, electrically charged black holes are found to be characterized only by the existence of a gravitational sector of perturbations. As in the case of neutral black holes, we demonstrate that for the bulk of electrically charged black holes no unstable modes arise in this sector. (c) 2000 The American Physical Society

Mass inflation in the loop black hole

International Nuclear Information System (INIS)

Brown, Eric G.; Mann, Robert; Modesto, Leonardo

2011-01-01

In classical general relativity the Cauchy horizon within a two-horizon black hole is unstable via a phenomenon known as mass inflation, in which the mass parameter (and the spacetime curvature) of the black hole diverges at the Cauchy horizon. Here we study this effect for loop black holes - quantum gravitationally corrected black holes from loop quantum gravity - whose construction alleviates the r=0 singularity present in their classical counterparts. We use a simplified model of mass inflation, which makes use of the generalized Dray-'t Hooft relation, to conclude that the Cauchy horizon of loop black holes indeed results in a curvature singularity similar to that found in classical black holes. The Dray-'t Hooft relation is of particular utility in the loop black hole because it does not directly rely upon Einstein's field equations. We elucidate some of the interesting and counterintuitive properties of the loop black hole, and corroborate our results using an alternate model of mass inflation due to Ori.

Entropy of black holes with multiple horizons

Directory of Open Access Journals (Sweden)

Yun He

2018-05-01

Full Text Available We examine the entropy of black holes in de Sitter space and black holes surrounded by quintessence. These black holes have multiple horizons, including at least the black hole event horizon and a horizon outside it (cosmological horizon for de Sitter black holes and “quintessence horizon” for the black holes surrounded by quintessence. Based on the consideration that the two horizons are not independent each other, we conjecture that the total entropy of these black holes should not be simply the sum of entropies of the two horizons, but should have an extra term coming from the correlations between the two horizons. Different from our previous works, in this paper we consider the cosmological constant as the variable and employ an effective method to derive the explicit form of the entropy. We also try to discuss the thermodynamic stabilities of these black holes according to the entropy and the effective temperature.

Electromagnetic ``black holes'' in hyperbolic metamaterials

Science.gov (United States)

Smolyaninov, Igor

2013-03-01

We demonstrate that spatial variations of the dielectric tensor components in a hyperbolic metamaterial may lead to formation of electromagnetic ``black holes'' inside this metamaterial. Similar to real black holes, horizon area of the electromagnetic ``black holes'' is quantized in units of the effective ``Planck scale'' squared. Potential experimental realizations of such electromagnetic ``black holes'' will be considered. For example, this situation may be realized in a hyperbolic metamaterial in which the dielectric component exhibits critical opalescence.

Black hole Berry phase

NARCIS (Netherlands)

de Boer, J.; Papadodimas, K.; Verlinde, E.

2009-01-01

Supersymmetric black holes are characterized by a large number of degenerate ground states. We argue that these black holes, like other quantum mechanical systems with such a degeneracy, are subject to a phenomenon which is called the geometric or Berry’s phase: under adiabatic variations of the

Black hole accretion: the quasar powerhouse

International Nuclear Information System (INIS)

Anon.

1983-01-01

A program is described which calculates the effects of material falling into the curved space-time surrounding a rotation black hole. The authors have developed a two-dimensional, general-relativistic hydrodynamics code to simulate fluid flow in the gravitational field of a rotating black hole. Such calculations represent models that have been proposed for the energy sources of both quasars and jets from radiogalaxies. In each case, the black hole that powers the quasar or jet would have a mass of about 100 million times the mass of the sun. The black hole would be located in the center of a galaxy whose total mass is 1000 time greater than the black hole mass. (SC)

Charged black holes with scalar hair

Energy Technology Data Exchange (ETDEWEB)

Fan, Zhong-Ying; Lü, H. [Center for Advanced Quantum Studies, Department of Physics,Beijing Normal University, Beijing 100875 (China)

2015-09-10

We consider a class of Einstein-Maxwell-Dilaton theories, in which the dilaton coupling to the Maxwell field is not the usual single exponential function, but one with a stationary point. The theories admit two charged black holes: one is the Reissner-Nordstrøm (RN) black hole and the other has a varying dilaton. For a given charge, the new black hole in the extremal limit has the same AdS{sub 2}×Sphere near-horizon geometry as the RN black hole, but it carries larger mass. We then introduce some scalar potentials and obtain exact charged AdS black holes. We also generalize the results to black p-branes with scalar hair.

Black hole thermodynamics with conical defects

Energy Technology Data Exchange (ETDEWEB)

Appels, Michael [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Gregory, Ruth [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Perimeter Institute,31 Caroline Street North, Waterloo, ON, N2L 2Y5 (Canada); Kubiznák, David [Perimeter Institute,31 Caroline Street North, Waterloo, ON, N2L 2Y5 (Canada)

2017-05-22

Recently we have shown https://www.doi.org/10.1103/PhysRevLett.117.131303 how to formulate a thermodynamic first law for a single (charged) accelerated black hole in AdS space by fixing the conical deficit angles present in the spacetime. Here we show how to generalise this result, formulating thermodynamics for black holes with varying conical deficits. We derive a new potential for the varying tension defects: the thermodynamic length, both for accelerating and static black holes. We discuss possible physical processes in which the tension of a string ending on a black hole might vary, and also map out the thermodynamic phase space of accelerating black holes and explore their critical phenomena.

Black hole evaporation: a paradigm

International Nuclear Information System (INIS)

Ashtekar, Abhay; Bojowald, Martin

2005-01-01

A paradigm describing black hole evaporation in non-perturbative quantum gravity is developed by combining two sets of detailed results: (i) resolution of the Schwarzschild singularity using quantum geometry methods and (ii) time evolution of black holes in the trapping and dynamical horizon frameworks. Quantum geometry effects introduce a major modification in the traditional spacetime diagram of black hole evaporation, providing a possible mechanism for recovery of information that is classically lost in the process of black hole formation. The paradigm is developed directly in the Lorentzian regime and necessary conditions for its viability are discussed. If these conditions are met, much of the tension between expectations based on spacetime geometry and structure of quantum theory would be resolved

Do Hypervolumes Have Holes?

Science.gov (United States)

Blonder, Benjamin

2016-04-01

Hypervolumes are used widely to conceptualize niches and trait distributions for both species and communities. Some hypervolumes are expected to be convex, with boundaries defined by only upper and lower limits (e.g., fundamental niches), while others are expected to be maximal, with boundaries defined by the limits of available space (e.g., potential niches). However, observed hypervolumes (e.g., realized niches) could also have holes, defined as unoccupied hyperspace representing deviations from these expectations that may indicate unconsidered ecological or evolutionary processes. Detecting holes in more than two dimensions has to date not been possible. I develop a mathematical approach, implemented in the hypervolume R package, to infer holes in large and high-dimensional data sets. As a demonstration analysis, I assess evidence for vacant niches in a Galapagos finch community on Isabela Island. These mathematical concepts and software tools for detecting holes provide approaches for addressing contemporary research questions across ecology and evolutionary biology.

When Black Holes Collide

Science.gov (United States)

Baker, John

2010-01-01

Among the fascinating phenomena predicted by General Relativity, Einstein's theory of gravity, black holes and gravitational waves, are particularly important in astronomy. Though once viewed as a mathematical oddity, black holes are now recognized as the central engines of many of astronomy's most energetic cataclysms. Gravitational waves, though weakly interacting with ordinary matter, may be observed with new gravitational wave telescopes, opening a new window to the universe. These observations promise a direct view of the strong gravitational dynamics involving dense, often dark objects, such as black holes. The most powerful of these events may be merger of two colliding black holes. Though dark, these mergers may briefly release more energy that all the stars in the visible universe, in gravitational waves. General relativity makes precise predictions for the gravitational-wave signatures of these events, predictions which we can now calculate with the aid of supercomputer simulations. These results provide a foundation for interpreting expect observations in the emerging field of gravitational wave astronomy.

Does black-hole entropy make sense

International Nuclear Information System (INIS)

Wilkins, D.

1979-01-01

Bekenstein and Hawking saved the second law of thermodynamics near a black hole by assigning to the hole an entropy Ssub(h) proportional to the area of its event horizon. It is tempting to assume that Ssub(h) possesses all the features commonly associated with the physical entropy. Kundt has shown, however, that Ssub(h) violates several reasonable physical expectations. This criticism is reviewed, augmenting it as follows: (a) Ssub(h) is a badly behaved state function requiring knowledge of the hole's future history; and (b) close analogs of event horizons in other space-times do not possess an 'entropy'. These questions are also discussed: (c) Is Ssub(h) suitable for all regions of a black-hole space-time. And (b) should Ssub(h) be attributed to the exterior of a white hole. One can retain Ssub(h) for the interior (respectively, exterior) of a black (respectively, white) hole, but is rejected as contrary to the information-theoretic derivation of horizon entropy given by Berkenstein. The total entropy defined by Kundt (all ordinary entropy on space-section cutting through the hole, no horizon term) and that of Bekenstein-Hawking (ordinary entropy outside horizon plus horizon term) appear to be complementary concepts with separate domains of validity. In the most natural choice, an observer inside a black hole will use Kundt's entropy, and one remaining outside that of Bekenstein-Hawking. (author)

Stationary black holes as holographs

Energy Technology Data Exchange (ETDEWEB)

Racz, Istvan [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-01 (Japan); MTA KFKI, Reszecske- es Magfizikai Kutatointezet, H-1121 Budapest, Konkoly Thege Miklos ut 29-33 (Hungary)

2007-11-21

Smooth spacetimes possessing a (global) one-parameter group of isometries and an associated Killing horizon in Einstein's theory of gravity are investigated. No assumption concerning the asymptotic structure is made; thereby, the selected spacetimes may be considered as generic distorted stationary black holes. First, spacetimes of arbitrary dimension, n {>=} 3, with matter satisfying the dominant energy condition and allowing a non-zero cosmological constant are investigated. In this part, complete characterization of the topology of the event horizon of 'distorted' black holes is given. It is shown that the topology of the event horizon of 'distorted' black holes is allowed to possess a much larger variety than that of the isolated black hole configurations. In the second part, four-dimensional (non-degenerate) electrovac distorted black hole spacetimes are considered. It is shown that the spacetime geometry and the electromagnetic field are uniquely determined in the black hole region once the geometry of the bifurcation surface and one of the electromagnetic potentials are specified there. Conditions guaranteeing the same type of determinacy, in a neighbourhood of the event horizon, on the domain of outer communication side are also investigated. In particular, they are shown to be satisfied in the analytic case.

Time dependent black holes and scalar hair

International Nuclear Information System (INIS)

Chadburn, Sarah; Gregory, Ruth

2014-01-01

We show how to correctly account for scalar accretion onto black holes in scalar field models of dark energy by a consistent expansion in terms of a slow roll parameter. At leading order, we find an analytic solution for the scalar field within our Hubble volume, which is regular on both black hole and cosmological event horizons, and compute the back reaction of the scalar on the black hole, calculating the resulting expansion of the black hole. Our results are independent of the relative size of black hole and cosmological event horizons. We comment on the implications for more general black hole accretion, and the no hair theorems. (paper)

Quantum Black Holes As Elementary Particles

OpenAIRE

Ha, Yuan K.

2008-01-01

Are black holes elementary particles? Are they fermions or bosons? We investigate the remarkable possibility that quantum black holes are the smallest and heaviest elementary particles. We are able to construct various fundamental quantum black holes: the spin-0, spin 1/2, spin-1, and the Planck-charge cases, using the results in general relativity. Quantum black holes in the neighborhood of the Galaxy could resolve the paradox posed by the Greisen-Zatsepin-Kuzmin limit on the energy of cosmi...

Internal limiting membrane flap transposition for surgical repair of macular holes in primary surgery and in persistent macular holes.

Science.gov (United States)

Leisser, Christoph; Hirnschall, Nino; Döller, Birgit; Varsits, Ralph; Ullrich, Marlies; Kefer, Katharina; Findl, Oliver

2018-03-01

Classical or temporal internal limiting membrane (ILM) flap transposition with air or gas tamponade are current trends with the potential to improve surgical results, especially in cases with large macular holes. A prospective case series included patients with idiopathic macular holes or persistent macular holes after 23-G pars plana vitrectomy (PPV) and ILM peeling with gas tamponade. In all patients, 23-G PPV and ILM peeling with ILM flap transposition with gas tamponade and postoperative face-down position was performed. In 7 of 9 eyes, temporal ILM flap transposition combined with pedicle ILM flap could be successfully performed and macular holes were closed in all eyes after surgery. The remaining 2 eyes were converted to pedicle ILM flap transposition with macular hole closure after surgery. Three eyes were scheduled as pedicle ILM flap transposition due to previous ILM peeling. In 2 of these eyes, the macular hole could be closed with pedicle ILM flap transposition. In 3 eyes, free ILM flap transposition was performed and in 2 of these eyes macular hole could be closed after surgery, whereas in 1 eye a second surgery, performed as pedicle ILM flap transposition, was performed and led to successful macular hole closure. Use of ILM flaps in surgical repair of macular hole surgery is a new option of treatment with excellent results independent of the diameter of macular holes. For patients with persistent macular holes, pedicle ILM flap transposition or free ILM flap transposition are surgical options.

NASA's Chandra Finds Black Holes Are "Green"

Science.gov (United States)

2006-04-01

Black holes are the most fuel efficient engines in the Universe, according to a new study using NASA's Chandra X-ray Observatory. By making the first direct estimate of how efficient or "green" black holes are, this work gives insight into how black holes generate energy and affect their environment. The new Chandra finding shows that most of the energy released by matter falling toward a supermassive black hole is in the form of high-energy jets traveling at near the speed of light away from the black hole. This is an important step in understanding how such jets can be launched from magnetized disks of gas near the event horizon of a black hole. Illustration of Fuel for a Black Hole Engine Illustration of Fuel for a Black Hole Engine "Just as with cars, it's critical to know the fuel efficiency of black holes," said lead author Steve Allen of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University, and the Stanford Linear Accelerator Center. "Without this information, we cannot figure out what is going on under the hood, so to speak, or what the engine can do." Allen and his team used Chandra to study nine supermassive black holes at the centers of elliptical galaxies. These black holes are relatively old and generate much less radiation than quasars, rapidly growing supermassive black holes seen in the early Universe. The surprise came when the Chandra results showed that these "quiet" black holes are all producing much more energy in jets of high-energy particles than in visible light or X-rays. These jets create huge bubbles, or cavities, in the hot gas in the galaxies. Animation of Black Hole in Elliptical Galaxy Animation of Black Hole in Elliptical Galaxy The efficiency of the black hole energy-production was calculated in two steps: first Chandra images of the inner regions of the galaxies were used to estimate how much fuel is available for the black hole; then Chandra images were used to estimate the power required to produce

Charged spinning black holes as particle accelerators

International Nuclear Information System (INIS)

Wei Shaowen; Liu Yuxiao; Guo Heng; Fu Chune

2010-01-01

It has recently been pointed out that the spinning Kerr black hole with maximal spin could act as a particle collider with arbitrarily high center-of-mass energy. In this paper, we will extend the result to the charged spinning black hole, the Kerr-Newman black hole. The center-of-mass energy of collision for two uncharged particles falling freely from rest at infinity depends not only on the spin a but also on the charge Q of the black hole. We find that an unlimited center-of-mass energy can be approached with the conditions: (1) the collision takes place at the horizon of an extremal black hole; (2) one of the colliding particles has critical angular momentum; (3) the spin a of the extremal black hole satisfies (1/√(3))≤(a/M)≤1, where M is the mass of the Kerr-Newman black hole. The third condition implies that to obtain an arbitrarily high energy, the extremal Kerr-Newman black hole must have a large value of spin, which is a significant difference between the Kerr and Kerr-Newman black holes. Furthermore, we also show that, for a near-extremal black hole, there always exists a finite upper bound for center-of-mass energy, which decreases with the increase of the charge Q.

Thermodynamics of the Schwarzschild-de Sitter black hole: Thermal stability of the Nariai black hole

International Nuclear Information System (INIS)

Myung, Yun Soo

2008-01-01

We study the thermodynamics of the Schwarzschild-de Sitter black hole in five dimensions by introducing two temperatures based on the standard and Bousso-Hawking normalizations. We use the first-law of thermodynamics to derive thermodynamic quantities. The two temperatures indicate that the Nariai black hole is thermodynamically unstable. However, it seems that black hole thermodynamics favors the standard normalization and does not favor the Bousso-Hawking normalization

Magnonic black holes

OpenAIRE

Roldán-Molina, A.; Nunez, A.S.; Duine, R. A.

2017-01-01

We show that the interaction between spin-polarized current and magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons - the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the imp...

Familial trends in a population with macular holes.

Science.gov (United States)

Kay, Christine Nichols; Pavan, Peter Reed; Small, Laurie Buccina; Zhang, Tao; Zamba, Gideon K D; Cohen, Steven Myles

2012-04-01

To determine if patients with macular hole report an increased family history of macular hole compared with control patients and compare the report of family history between patients with unilateral and bilateral macular holes. This was a multicenter case-control study. Charts of patients coded with diagnosis of macular hole were reviewed, and the diagnosis of idiopathic full-thickness macular hole was ascertained in 166 patients. The control group comprised 136 patients without macular hole or trauma who presented with senile cataract. Family history was obtained from all patients through a telephone interview. Six of 166 (3.6%) macular hole patients surveyed reported a history of macular hole in a primary relative compared with none of 136 (0.0%) control patients (odds ratio is infinity, with 95% confidence interval 1.295 to infinity); however, this finding may be explained by confounders such as age and number of family members. Two of the 142 (1.4%) patients with unilateral holes versus 4 of the 24 (16.7%) patients with bilateral holes reported a family history (odds ratio is 0.0714, with 95% confidence interval 0.0063 to 0.5537), and this finding remains significant when logistic regression is performed to evaluate variables of age and number of family members as potential confounders. There is an increased report of familial occurrence of macular hole in patients with macular holes compared with control patients; however, logistic regression relates this finding to variables of age and number of family members. Patients with bilateral macular holes are more likely to report a family history of macular hole than patients with unilateral macular holes, and this finding remains significant in the presence of age and number of family members. These findings may suggest a familial component to macular hole.

Charged topological black hole pair creation

International Nuclear Information System (INIS)

Mann, R.B.

1998-01-01

I examine the pair creation of black holes in space-times with a cosmological constant of either sign. I consider cosmological C-metrics and show that the conical singularities in this metric vanish only for three distinct classes of black hole metric, two of which have compact event horizons on each spatial slice. One class is a generalization of the Reissner-Nordstroem (anti-)de Sitter black holes in which the event horizons are the direct product of a null line with a 2-surface with topology of genus g. The other class consists of neutral black holes whose event horizons are the direct product of a null conoid with a circle. In the presence of a domain wall, black hole pairs of all possible types will be pair created for a wide range of mass and charge, including even negative mass black holes. I determine the relevant instantons and Euclidean actions for each case. (orig.)

The membrane paradigm for black holes

International Nuclear Information System (INIS)

Price, R.H.; Thorne, K.S.

1988-01-01

It is now widely accepted that black holes exist and have an astrophysical role, in particular as the likely power source of quasars. To understand this role with ease, the authors and their colleagues have developed a new paradigm for black holes - a new way to picture, think about and describe them. As far as possible it treats black holes as ordinary astrophysical objects, made of real material. A black hole in this description is a spherical or oblate surface made of a thin, electrically conducting membrane. It was the author's quest to understand the Blandford-Znajek process intuitively that led them to create the membrane paradigm. Their strategy was to translate the general-relativistic mathematics of black holes into the same language of three-dimensional space that is used for magnetized plasmas and to create a new set of black-hole diagrams and pictures to go along with the language. 9 figs

Seeding black holes in cosmological simulations

Science.gov (United States)

Taylor, P.; Kobayashi, C.

2014-08-01

We present a new model for the formation of black holes in cosmological simulations, motivated by the first star formation. Black holes form from high density peaks of primordial gas, and grow via both gas accretion and mergers. Massive black holes heat the surrounding material, suppressing star formation at the centres of galaxies, and driving galactic winds. We perform an investigation into the physical effects of the model parameters, and obtain a `best' set of these parameters by comparing the outcome of simulations to observations. With this best set, we successfully reproduce the cosmic star formation rate history, black hole mass-velocity dispersion relation, and the size-velocity dispersion relation of galaxies. The black hole seed mass is ˜103 M⊙, which is orders of magnitude smaller than that which has been used in previous cosmological simulations with active galactic nuclei, but suggests that the origin of the seed black holes is the death of Population III stars.

Conserved size and periodicity of pyramidal patches in layer 2 of medial/caudal entorhinal cortex

Science.gov (United States)

Naumann, Robert K.; Ray, Saikat; Prokop, Stefan; Las, Liora; Heppner, Frank L.

2016-01-01

ABSTRACT To understand the structural basis of grid cell activity, we compare medial entorhinal cortex architecture in layer 2 across five mammalian species (Etruscan shrews, mice, rats, Egyptian fruit bats, and humans), bridging ∼100 million years of evolutionary diversity. Principal neurons in layer 2 are divided into two distinct cell types, pyramidal and stellate, based on morphology, immunoreactivity, and functional properties. We confirm the existence of patches of calbindin‐positive pyramidal cells across these species, arranged periodically according to analyses techniques like spatial autocorrelation, grid scores, and modifiable areal unit analysis. In rodents, which show sustained theta oscillations in entorhinal cortex, cholinergic innervation targeted calbindin patches. In bats and humans, which only show intermittent entorhinal theta activity, cholinergic innervation avoided calbindin patches. The organization of calbindin‐negative and calbindin‐positive cells showed marked differences in entorhinal subregions of the human brain. Layer 2 of the rodent medial and the human caudal entorhinal cortex were structurally similar in that in both species patches of calbindin‐positive pyramidal cells were superimposed on scattered stellate cells. The number of calbindin‐positive neurons in a patch increased from ∼80 in Etruscan shrews to ∼800 in humans, only an ∼10‐fold over a 20,000‐fold difference in brain size. The relatively constant size of calbindin patches differs from cortical modules such as barrels, which scale with brain size. Thus, selective pressure appears to conserve the distribution of stellate and pyramidal cells, periodic arrangement of calbindin patches, and relatively constant neuron number in calbindin patches in medial/caudal entorhinal cortex. J. Comp. Neurol. 524:783–806, 2016. © 2015 The Authors. The Journal of Comparative Neurology Published by Wiley Periodicals, Inc. PMID:26223342

Calcium K-line network in coronal holes

Energy Technology Data Exchange (ETDEWEB)

Marsh, K A [Hale Observatories, Pasadena, Calif. (USA)

1977-05-01

Microphotometry of calcium K-line photographs in the regions of polar coronal holes shows that the chromospheric network exterior to a hole has a slightly broader intensity distribution than that inside the hole itself, a fact which can be attributed to a greater number of bright network elements outside the hole. These bright elements presumably represent the enhanced network resulting from the dispersal of magnetic flux from old active regions, a hypothesis which is consistent with current ideas of coronal hole formation.

Greybody factors for d-dimensional black holes

DEFF Research Database (Denmark)

Harmark, Troels; Natário, José; Schiappa, Ricardo

2010-01-01

Gravitational greybody factors are analytically computed for static, spherically symmetric black holes in d-dimensions, including black holes with charge and in the presence of a cosmological constant (where a proper definition of greybody factors for both asymptotically de Sitter and anti...... of the details of the black hole. For asymptotically de Sitter black holes the greybody factor is different for even or odd spacetime dimension, and proportional to the ratio of the areas of the event and cosmological horizons. For asymptotically Ads black holes the greybody factor has a rich structure in which...... universality is hidden in the transmission and reflection coefficients. For either charged or asymptotically de Sitter black holes the greybody factors are given by non-trivial functions, while for asymptotically Ads black holes the greybody factor precisely equals one (corresponding to pure blackbody emission)....

Influencia del caudal de aire, temperatura y velocidad de agitación en el proceso discontinuo de acetificación para la obtención de vinagre de naranja (Citrus sinensis var.W. Navel

Directory of Open Access Journals (Sweden)

María Ferreyra

2012-01-01

Full Text Available Se describe la influencia de variables de proceso para la producción de vinagre de naranja. El jugo de naranja, se fermentó con Saccharomyces cer evisiae hasta 14 % v/v de alcohol. La bioxidación se realizó con Acetobacter sp., en cultivo sumergido, en biorreactor de laboratorio. Para evitar el efecto inhibidor del etanol sobre las bacterias acéticas, el vino de naranja fue diluido a 6 % v/v de alco hol con solución de minerales. La influencia de las variables se evaluó con diseño factorial 2 k . Se estudió caudal de aire/velocidad de agitación, ensayando los niveles 0.3 – 0.6 vvm y 200 - 400 rpm y luego, caudal de aire/temperatura, siendo los niveles para cada variable 0.4 – 0.6 vvm y 25 - 30 ºC, respectivamente. Cada tratamiento se realizó por duplicado, usando como respuestas productividad y rendimiento. El análisis del diseño (α<0.05 se efectuó mediante programa Statgraphics Centurion XV Corporate. En los tratamientos con 200 rpm y distintos caudales de aire, no hubo diferencias significativas respecto a la productividad. A mayor velocidad de agitación y caudal de aire, la productividad fue mayor. Los mayores rendimientos se obtuvieron con menores caudales de aire y mayores velocidades de agitación. Con respecto a la temperatura, los valores ensayados no presentaron diferenc ias significativas en las respuestas estudiadas. El mejor rendimiento se obtuvo con 400 rpm y 0.3 vvm a 25 ºC. Se concluye que la velocidad de agitación juega un rol muy importante para lograr una mejor productividad mientras que elevados flujos de aire d isminuyen el rendimiento.

High precision, rapid laser hole drilling

Science.gov (United States)

Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

2013-04-02

A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

Entropy evaporated by a black hole

International Nuclear Information System (INIS)

Zurek, W.H.

1982-01-01

It is shown that the entropy of the radiation evaporated by an uncharged, nonrotating black hole into vacuum in the course of its lifetime is approximately (4/3) times the initial entropy of this black hole. Also considered is a thermodynamically reversible process in which an increase of black-hole entropy is equal to the decrease of the entropy of its surroundings. Implications of these results for the generalized second law of thermodynamics and for the interpretation of black-hole entropy are pointed out

Rotating black holes and Coriolis effect

Directory of Open Access Journals (Sweden)

Chia-Jui Chou

2016-10-01

Full Text Available In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the suitable boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black hole under the holographic picture.

Rotating black holes and Coriolis effect

Energy Technology Data Exchange (ETDEWEB)

Chou, Chia-Jui, E-mail: agoodmanjerry.ep02g@nctu.edu.tw [Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan, ROC (China); Wu, Xiaoning, E-mail: wuxn@amss.ac.cn [Institute of Mathematics, Academy of Mathematics and System Science, CAS, Beijing, 100190 (China); Yang, Yi, E-mail: yiyang@mail.nctu.edu.tw [Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan, ROC (China); Yuan, Pei-Hung, E-mail: phyuan.py00g@nctu.edu.tw [Institute of Physics, National Chiao Tung University, Hsinchu, Taiwan, ROC (China)

2016-10-10

In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the suitable boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black hole under the holographic picture.

Black Hole Complementary Principle and Noncommutative Membrane

International Nuclear Information System (INIS)

Wei Ren

2006-01-01

In the spirit of black hole complementary principle, we have found the noncommutative membrane of Scharzchild black holes. In this paper we extend our results to Kerr black hole and see the same story. Also we make a conjecture that spacetimes are noncommutative on the stretched membrane of the more general Kerr-Newman black hole.

Dual jets from binary black holes.

Science.gov (United States)

Palenzuela, Carlos; Lehner, Luis; Liebling, Steven L

2010-08-20

The coalescence of supermassive black holes--a natural outcome when galaxies merge--should produce gravitational waves and would likely be associated with energetic electromagnetic events. We have studied the coalescence of such binary black holes within an external magnetic field produced by the expected circumbinary disk surrounding them. Solving the Einstein equations to describe black holes interacting with surrounding plasma, we present numerical evidence for possible jets driven by these systems. Extending the process described by Blandford and Znajek for a single, spinning black hole, the picture that emerges suggests that the electromagnetic field extracts energy from the orbiting black holes, which ultimately merge and settle into the standard Blandford-Znajek scenario. Emissions along these jets could potentially be observable at large distances.

Optimal management of idiopathic macular holes.

Science.gov (United States)

Madi, Haifa A; Masri, Ibrahim; Steel, David H

2016-01-01

This review evaluates the current surgical options for the management of idiopathic macular holes (IMHs), including vitrectomy, ocriplasmin (OCP), and expansile gas use, and discusses key background information to inform the choice of treatment. An evidence-based approach to selecting the best treatment option for the individual patient based on IMH characteristics and patient-specific factors is suggested. For holes without vitreomacular attachment (VMA), vitrectomy is the only option with three key surgical variables: whether to peel the inner limiting membrane (ILM), the type of tamponade agent to be used, and the requirement for postoperative face-down posturing. There is a general consensus that ILM peeling improves primary anatomical hole closure rate; however, in small holes (holes, but large (>400 µm) and chronic holes (>1-year history) are usually treated with long-acting gas and posturing. Several studies on posturing and gas choice were carried out in combination with ILM peeling, which may also influence the gas and posturing requirement. Combined phacovitrectomy appears to offer more rapid visual recovery without affecting the long-term outcomes of vitrectomy for IMH. OCP is licensed for use in patients with small- or medium-sized holes and VMA. A greater success rate in using OCP has been reported in smaller holes, but further predictive factors for its success are needed to refine its use. It is important to counsel patients realistically regarding the rates of success with intravitreal OCP and its potential complications. Expansile gas can be considered as a further option in small holes with VMA; however, larger studies are required to provide guidance on its use.

Black Holes at the LHC: Progress since 2002

International Nuclear Information System (INIS)

Park, Seong Chan

2008-01-01

We review the recent noticeable progresses in black hole physics focusing on the up-coming super-collider, the LHC. We discuss the classical formation of black holes by particle collision, the greybody factors for higher dimensional rotating black holes, the deep implications of black hole physics to the 'energy-distance' relation, the security issues of the LHC associated with black hole formation and the newly developed Monte-Carlo generators for black hole events.

Boosting jet power in black hole spacetimes.

Science.gov (United States)

Neilsen, David; Lehner, Luis; Palenzuela, Carlos; Hirschmann, Eric W; Liebling, Steven L; Motl, Patrick M; Garrett, Travis

2011-08-02

The extraction of rotational energy from a spinning black hole via the Blandford-Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux.

Filling bore-holes with explosive

Energy Technology Data Exchange (ETDEWEB)

Alfredsson, S H

1965-03-02

In this device for filling boreholes formed in a rock formation with particulate explosive, the explosive is conveyed into the hole by means of a pressure fluid through a tube which has a lesser diameter than the hole. The tube is characterized by a lattice work arranged externally on it, and having a structure adapted to allow passage of a pressure fluid returning between the tube and the wall of the hole, but retaining particles of explosive entrained by the returning pressure fluid. In another arrangement of the device, the lattice work has the form of a brush, including filaments or bristles which are dimensioned to bridge the spacing between the tube and the wall of the hole. (12 claims)

Hawking radiation and strong gravity black holes

International Nuclear Information System (INIS)

Qadir, A.; Sayed, W.A.

1979-01-01

It is shown that the strong gravity theory of Salam et al. places severe restrictions on black hole evaporation. Two major implications are that: mini blck holes (down to masses approximately 10 -16 kg) would be stable in the present epoch; and that some suggested mini black hole mechanisms to explain astrophysical phenomena would not work. The first result implies that f-gravity appears to make black holes much safer by removing the possibility of extremely violent black hole explosions suggested by Hawking. (Auth.)

The statistical clustering of primordial black holes

International Nuclear Information System (INIS)

Carr, B.J.

1977-01-01

It is shown that Meszaros theory of galaxy formation, in which galaxies form from the density perturbations associated with the statistical fluctuation in the number density of primordial black holes, must be modified if the black holes are initially surrounded by regions of lower radiation density than average (as is most likely). However, even in this situation, the sort of effect Meszaros envisages does occur and could in principle cause galactic mass-scales to bind at the conventional time. In fact, the requirement that galaxies should not form prematurely implies that black holes could not have a critical density in the mass range above 10 5 M(sun). If the mass spectrum of primordial black holes falls off more slowly than m -3 (as expected), then the biggest black holes have the largest clustering effect. In this case the black hole clustering theory of galaxy formation reduces to the black hole seed theory of galaxy formation, in which each galaxy becomes bound under the gravitational influence of a single black hole nucleus. The seed theory could be viable only if the early Universe had a soft equation of state until a time exceeding 10 -4 s or if something prevented black hole formation before 1 s. (orig.) [de

Plasma horizons of a charged black hole

International Nuclear Information System (INIS)

Hanni, R.S.

1977-01-01

The most promising way of detecting black holes seems to be through electromagnetic radiation emitted by nearby charged particles. The nature of this radiation depends strongly on the local electromagnetic field, which varies with the charge of the black hole. It has often been purported that a black hole with significant charge will not be observed, because, the dominance of the Coulomb interaction forces its neutralization through selective accretion. This paper shows that it is possible to balance the electric attraction of particles whose charge is opposite that of the black hole with magnetic forces and (assuming an axisymmetric, stationary solution) covariantly define the regions in which this is possible. A Kerr-Newman hole in an asymptotically uniform magnetic field and a current ring centered about a Reissner-Nordstroem hole are used as examples, because of their relevance to processes through which black holes may be observed. (Auth.)

Supersymmetric black holes

OpenAIRE

de Wit, Bernard

2005-01-01

The effective action of $N=2$, $d=4$ supergravity is shown to acquire no quantum corrections in background metrics admitting super-covariantly constant spinors. In particular, these metrics include the Robinson-Bertotti metric (product of two 2-dimensional spaces of constant curvature) with all 8 supersymmetries unbroken. Another example is a set of arbitrary number of extreme Reissner-Nordstr\\"om black holes. These black holes break 4 of 8 supersymmetries, leaving the other 4 unbroken. We ha...

LIGO Finds Lightest Black-Hole Binary

Science.gov (United States)

Kohler, Susanna

2017-11-01

Wednesdayevening the Laser Interferometer Gravitational-wave Observatory (LIGO) collaboration quietly mentioned that theyd found gravitational waves from yet another black-hole binary back in June. This casual announcement reveals what is so far the lightest pair of black holes weve watched merge opening the door for comparisons to the black holes weve detected by electromagnetic means.A Routine DetectionThe chirp signal of GW170608 detected by LIGO Hanford and LIGO Livingston. [LIGO collaboration 2017]After the fanfare of the previous four black-hole-binary merger announcements over the past year and a half as well as the announcement of the one neutron-star binary merger in August GW170608 marks our entry into the era in which gravitational-wave detections are officially routine.GW170608, a gravitational-wave signal from the merger of two black holes roughly a billion light-years away, was detected in June of this year. This detection occurred after wed already found gravitational waves from several black-hole binaries with the two LIGO detectors in the U.S., but before the Virgo interferometer came online in Europe and increased the joint ability of the detectors to localize sources.Mass estimates for the two components of GW170608 using different models. [LIGO collaboration 2017]Overall, GW170608 is fairly unremarkable: it was detected by both LIGO Hanford and LIGO Livingston some 7 ms apart, and the signal looks not unlike those of the previous LIGO detections. But because were still in the early days of gravitational-wave astronomy, every discovery is still remarkable in some way! GW170608 stands out as being the lightest pair of black holes weve yet to see merge, with component masses before the merger estimated at 12 and 7 times the mass of the Sun.Why Size MattersWith the exception of GW151226, the gravitational-wave signal discovered on Boxing Day last year, all of the black holes that have been discovered by LIGO/Virgo have been quite large: the masses

Black-hole astrophysics

Energy Technology Data Exchange (ETDEWEB)

Bender, P. [Univ. of Colorado, Boulder, CO (United States); Bloom, E. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Cominsky, L. [Sonoma State Univ., Rohnert Park, CA (United States). Dept. of Physics and Astronomy] [and others

1995-07-01

Black-hole astrophysics is not just the investigation of yet another, even if extremely remarkable type of celestial body, but a test of the correctness of the understanding of the very properties of space and time in very strong gravitational fields. Physicists` excitement at this new prospect for testing theories of fundamental processes is matched by that of astronomers at the possibility to discover and study a new and dramatically different kind of astronomical object. Here the authors review the currently known ways that black holes can be identified by their effects on their neighborhood--since, of course, the hole itself does not yield any direct evidence of its existence or information about its properties. The two most important empirical considerations are determination of masses, or lower limits thereof, of unseen companions in binary star systems, and measurement of luminosity fluctuations on very short time scales.

Cosmology with primordial black holes

International Nuclear Information System (INIS)

Lindley, D.

1981-09-01

Cosmologies containing a substantial amount of matter in the form of evaporating primordial black holes are investigated. A review of constraints on the numbers of such black holes, including an analysis of a new limit found by looking at the destruction of deuterium by high energy photons, shows that there must be a negligible population of small black holes from the era of cosmological nucleosynthesis onwards, but that there are no strong constraints before this time. The major part of the work is based on the construction of detailed, self-consistent cosmological models in which black holes are continually forming and evaporating The interest in these models centres on the question of baryon generation, which occurs via the asymmetric decay of a new type of particle which appears as a consequence of the recently developed Grand Unified Theories of elementary particles. Unfortunately, there is so much uncertainty in the models that firm conclusions are difficult to reach; however, it seems feasible in principle that primordial black holes could be responsible for a significant part of the present matter density of the Universe. (author)

Black holes with Yang-Mills hair

International Nuclear Information System (INIS)

Kleihaus, B.; Kunz, J.; Sood, A.; Wirschins, M.

1998-01-01

In Einstein-Maxwell theory black holes are uniquely determined by their mass, their charge and their angular momentum. This is no longer true in Einstein-Yang-Mills theory. We discuss sequences of neutral and charged SU(N) Einstein-Yang-Mills black holes, which are static spherically symmetric and asymptotically flat, and which carry Yang-Mills hair. Furthermore, in Einstein-Maxwell theory static black holes are spherically symmetric. We demonstrate that, in contrast, SU(2) Einstein-Yang-Mills theory possesses a sequence of black holes, which are static and only axially symmetric

Tidal interactions with Kerr black holes

International Nuclear Information System (INIS)

Hiscock, W.A.

1977-01-01

The tidal deformation of an extended test body falling with zero angular momentum into a Kerr black hole is calculated. Numerical results for infall along the symmetry axis and in the equatorial plane of the black hole are presented for a range of values of a, the specific angular momentum of the black hole. Estimates of the tidal contribution to the gravitational radiation are also given. The tidal contribution in equatorial infall into a maximally rotating Kerr black hole may be of the same order as the center-of-mass contribution to the gravitational radiation

Noncommutative Black Holes at the LHC

Science.gov (United States)

Villhauer, Elena Michelle

2017-12-01

Based on the latest public results, 13 TeV data from the Large Hadron Collider at CERN has not indicated any evidence of hitherto tested models of quantum black holes, semiclassical black holes, or string balls. Such models have predicted signatures of particles with high transverse momenta. Noncommutative black holes remain an untested model of TeV-scale gravity that offers the starkly different signature of particles with relatively low transverse momenta. Considerations for a search for charged noncommutative black holes using the ATLAS detector will be discussed.

Destroying black holes with test bodies

Energy Technology Data Exchange (ETDEWEB)

Jacobson, Ted [Center for Fundamental Physics, University of Maryland, College Park, MD 20742-4111 (United States); Sotiriou, Thomas P, E-mail: jacobson@umd.ed, E-mail: T.Sotiriou@damtp.cam.ac.u [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)

2010-04-01

If a black hole can accrete a body whose spin or charge would send the black hole parameters over the extremal limit, then a naked singularity would presumably form, in violation of the cosmic censorship conjecture. We review some previous results on testing cosmic censorship in this way using the test body approximation, focusing mostly on the case of neutral black holes. Under certain conditions a black hole can indeed be over-spun or over-charged in this approximation, hence radiative and self-force effects must be taken into account to further test cosmic censorship.

Charged black holes in phantom cosmology

Energy Technology Data Exchange (ETDEWEB)

Jamil, Mubasher; Qadir, Asghar; Rashid, Muneer Ahmad [National University of Sciences and Technology, Center for Advanced Mathematics and Physics, Rawalpindi (Pakistan)

2008-11-15

In the classical relativistic regime, the accretion of phantom-like dark energy onto a stationary black hole reduces the mass of the black hole. We have investigated the accretion of phantom energy onto a stationary charged black hole and have determined the condition under which this accretion is possible. This condition restricts the mass-to-charge ratio in a narrow range. This condition also challenges the validity of the cosmic-censorship conjecture since a naked singularity is eventually produced due to accretion of phantom energy onto black hole. (orig.)