bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of the cardiovascular response to stress by systemic 5-HT1Aactivation: sympathoinhibition or anxiolysis?
Authors: Vianna Daniel M. L. , Carrive Pascal
Published: June 2009

5-HT1Aagonists given systemically are known to produce anxiolytic effects. In addition, a growing body of research is showing that those compounds also have central sympathoinhibitory properties. Since emotional arousal gives rise to sympathetic activation, it is not clear whether systemic treatment with a 5-HT1Aagonist reduces the sympathetic response to emotional stress primarily by a direct action on sympathetic-related sites in the brain or indirectly through reducing anxiety. To test this, we compared the effect of intraperitoneal injections of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT; 0.05 and 0.25 mg/kg), a preferential 5-HT1Aagonist, or vehicle on the cardiovascular responses to four stressors known to produce sympathetic activation, three being emotional stressors, and one physiological. In conscious rats, 30-min exposure to either a neutral context, a fear-conditioned context, or to restraint stress led to increases in heart rate and blood pressure, which were attenuated by 8-OH-DPAT. In contrast, the same treatment did not reduce the cardiovascular response to 30-min cold exposure (4°C). The results suggest that 8-OH-DPAT acts preferentially on limbic, rather than central, autonomic sites. Hence, doses of 5-HT1Aagonists, which are just sufficient to produce anxiolysis, are not enough to cause true sympathoinhibition.
Cardiovascular responses to hydrogen peroxide into the nucleus tractus solitarius
Authors: Cardoso Leonardo Máximo , Colombari Débora Simões de Almeida , Menani José V. , Toney Glenn M. , Chianca Deoclécio Alves , Colombari Eduardo
Published: June 2009

The nucleus tractus solitarius (NTS), a major hindbrain area involved in cardiovascular regulation, receives primary afferent fibers from peripheral baroreceptors and chemoreceptors. Hydrogen peroxide (H2O2) is a relatively stable and diffusible reactive oxygen species (ROS), which acting centrally, may affect neural mechanisms. In the present study, we investigated effects of H2O2alone or combined with the glutamatergic antagonist kynurenate into the NTS on mean arterial pressure (MAP) and heart rate (HR). Conscious or anesthetized (urethane and α-chloralose) male Holtzman rats (280–320 g) were used. Injections of H2O2(125 to 1500 pmol/40 nl) into the intermediate NTS of anesthetized rats evoked dose-dependent and transient hypotension (−18 ± 3 to −55 ± 11 mmHg) and bradycardia (−16 ± 5 to −116 ± 40 bpm). Injection of the catalase inhibitor 3-amino-1,2,4-triazole (100 nmol/40 nl) into the NTS also produced hypotension and bradycardia. Previous injection of the ionotropic l-glutamate receptor antagonist kynurenate (7 nmol/40 nl) attenuated by 48% the bradycardic response, without changing the hypotension evoked by H2O2(500 pmol/40 nl) in anesthetized rats. The antioxidant l-ascorbate (600 pmol/80 nl) injected into the NTS attenuated the bradycardic (42%) and hypotensive (67%) responses to H2O2(500 pmol/40 nl) into the NTS. In conscious rats, injection of H2O2(50 nmol/100 nl) into the NTS also evoked intense bradycardia (−207 ± 8 bpm) and hypotension (−54 ± 6 mmHg) that were abolished by prior injection of kynurenate (7 nmol/100 nl). The results show that H2O2into the NTS induces hypotension and bradycardia probably due to activation of glutamatergic mechanisms.
Dorsal spinal cord stimulation obtunds the capacity of intrathoracic extracardiac neurons to transduce myocardial ischemia
Authors: Ardell Jeffrey L. , Cardinal René , Vermeulen Michel , Armour J. Andrew
Published: June 2009

Populations of intrathoracic extracardiac neurons transduce myocardial ischemia, thereby contributing to sympathetic control of regional cardiac indices during such pathology. Our objective was to determine whether electrical neuromodulation using spinal cord stimulation (SCS) modulates such local reflex control. In 10 anesthetized canines, middle cervical ganglion neurons were identified that transduce the ventricular milieu. Their capacity to transduce a global (rapid ventricular pacing) vs. regional (transient regional ischemia) ventricular stress was tested before and during SCS (50 Hz, 0.2 ms duration at 90% MT) applied to the dorsal aspect of the T1 to T4 spinal cord. Rapid ventricular pacing and transient myocardial ischemia both activated cardiac-related middle cervical ganglion neurons. SCS obtunded their capacity to reflexly respond to the regional ventricular ischemia, but not rapid ventricular pacing. In conclusion, spinal cord inputs to the intrathoracic extracardiac nervous system obtund the latter's capacity to transduce regional ventricular ischemia, but not global cardiac stress. Given the substantial body of literature indicating the adverse consequences of excessive adrenergic neuronal excitation on cardiac function, these data delineate the intrathoracic extracardiac nervous system as a potential target for neuromodulation therapy in minimizing such effects.
Cyclooxygenase-1 or -2—which one mediates lipopolysaccharide-induced hypothermia?
Authors: Steiner Alexandre A. , Hunter John C. , Phipps Sean M. , Nucci Tatiane B. , Oliveira Daniela L. , Roberts Jennifer L. , Scheck Adrienne C. , Simmons Daniel L. , Romanovsky Andrej A.
Published: June 2009

Systemic inflammation is associated with either fever or hypothermia. Fever, a response to mild systemic inflammation, is mediated by cyclooxygenase (COX)-2 and not by COX-1. However, it is still disputed whether COX-2, COX-1, neither, or both mediate(s) responses to severe systemic inflammation, and, in particular, the hypothermic response. We compared the effects of SC-236 (COX-2 inhibitor) and SC-560 (COX-1 inhibitor) on the deep body temperature (Tb) of rats injected with a lower (10 μg/kg iv) or higher (1,000 μg/kg iv) dose of LPS at different ambient temperatures (Tas). At a neutral Ta(30°C), the rats responded to LPS with a polyphasic fever (lower dose) or a brief hypothermia followed by fever (higher dose). SC-236 (2.5 mg/kg iv) blocked the fever induced by either LPS dose, whereas SC-560 (5 mg/kg iv) altered neither the febrile response to the lower LPS dose nor the fever component of the response to the higher dose. However, SC-560 blocked the initial hypothermia caused by the higher LPS dose. At a subneutral Ta(22°C), the rats responded to LPS with early (70–90 min, nadir) dose-dependent hypothermia. The hypothermic response to either dose was enhanced by SC-236 but blocked by SC-560. The hypothermic response to the higher LPS dose was associated with a fall in arterial blood pressure. This hypotensive response was attenuated by either SC-236 or SC-560. At the onset of LPS-induced hypothermia and hypotension, the functional activity of the COX-1 pathway (COX-1-mediated PGE2synthesis ex vivo) increased in the spleen but not liver, lung, kidney, or brain. The expression of splenic COX-1 was unaffected by LPS. We conclude that COX-1, but not COX-2, mediates LPS hypothermia, and that both COX isoforms are required for LPS hypotension.
Interactive effect of aging and local muscle heating on renal vasoconstriction during isometric handgrip
Authors: Kuipers Nathan T. , Sauder Charity L. , Kearney Matthew L. , Ray Chester A.
Published: June 2009

The purpose of the study was to determine the interactive effect of aging and forearm muscle heating on renal vascular conductance and muscle sympathetic nerve activity (MSNA) during ischemic isometric handgrip. A tube-lined, water-perfused sleeve was used to heat the forearm in 12 young (27 ± 1 yr) and 9 older (63 ± 1 yr) subjects. Ischemic isometric handgrip was performed before and after heating. Muscle temperature (intramuscular thermistor) was 34.3 ± 0.2 and 38.7 ± 0.1°C during normothermia and heating, respectively. At rest, heating had no effect on renal blood velocity (Doppler ultrasound) or renal vascular conductance in either group (young, n = 12; older, n = 8). Heating compared with normothermia caused a significantly greater increase in renal vasoconstriction during exercise and postexercise muscle ischemia (PEMI) in both groups. However, the increase in renal vasoconstriction during heating was greater in the older compared with the young subjects (18 ± 3 vs. 8 ± 3%). During handgrip, heating elicited greater increases in MSNA responses in the older group (young, n = 12; older, n = 6), whereas no statistical difference was observed between groups during PEMI. In summary, aging augments renal vascular responses to ischemic isometric handgrip during heating of the exercising muscle. The greater renal vasoconstriction was associated with augmented MSNA in the older subjects.
AVP-stimulated nucleotide secretion in perfused mouse medullary thick ascending limb and cortical collecting duct
Authors: Odgaard Elvin , Praetorius Helle A. , Leipziger Jens
Published: June 2009

Extracellular nucleotides are local, short-lived signaling molecules that inhibit renal tubular transport via both luminal and basolateral P2 receptors. Apparently, the renal epithelium itself is able to release nucleotides. The mechanism and circumstances under which nucleotide release is stimulated remain elusive. Here, we investigate the phenomenon of nucleotide secretion in intact, perfused mouse medullary thick ascending limb (mTAL) and cortical collecting duct (CCD). The nucleotide secretion was monitored by a biosensor adapted to register nucleotides in the tubular outflow. Intracellular Ca2+concentration ([Ca2+]i) was measured simultaneously in the biosensor cells and the renal tubule with fluo 4. We were able to identify spontaneous tubular nucleotide secretion in resting perfused mTAL. In this preparation, 10 nM AVP and 1-desamino-8-d-arginine vasopressin (dDAVP) induced robust [Ca2+]ioscillations, whereas AVP in the CCD induced large, slow, and transient [Ca2+]ielevations. Importantly, we identify that AVP/dDAVP triggers tubular secretion of nucleotides in the mTAL. After addition of AVP/dDAVP, the biosensor registered bursts of nucleotides in the tubular perfusate, corresponding to a tubular nucleotide concentration of ∼0.2–0.3 μM. A very similar response was observed after AVP stimulation of CCDs. Thus AVP stimulated tubular secretion of nucleotides in a burst-like pattern with peak tubular nucleotide concentrations in the low-micromolar range. We speculate that local nucleotide signaling is an intrinsic feedback element of hormonal control of renal tubular transport.
Syntaxin specificity of aquaporins in the inner medullary collecting duct
Authors: Mistry Abinash C. , Mallick Rickta , Klein Janet D. , Weimbs Thomas , Sands Jeff M. , Fröhlich Otto
Published: June 2009

Proper targeting of the aquaporin-2 (AQP2) water channel to the collecting duct apical plasma membrane is critical for the urine concentrating mechanism and body water homeostasis. However, the trafficking mechanisms that recruit AQP2 to the plasma membrane are still unclear. Snapin is emerging as an important mediator in the initial interaction of trafficked proteins with target soluble N-ethylmaleimide-sensitive factor attachment protein (SNAP) receptor (t-SNARE) proteins, and this interaction is functionally important for AQP2 regulation. We show that in AQP2-Madin-Darby canine kidney cells subjected to adenoviral-mediated expression of both snapin and syntaxins, the association of AQP2 with both syntaxin-3 and syntaxin-4 is highly enhanced by the presence of snapin. In pull-down studies, snapin detected AQP2, syntaxin-3, syntaxin-4, and SNAP23 from the inner medullary collecting duct. AQP2 transport activity, as probed by AQP2's urea permeability, was greatly enhanced in oocytes that were coinjected with cRNAs of SNARE components (snapin+syntaxin-3+SNAP23) over those injected with AQP2 cRNA alone. It was not enhanced when syntaxin-3 was replaced by syntaxin-4 (snapin+syntaxin-4+SNAP23). On the other hand, the latter combination significantly enhanced the transport activity of the related AQP3 water channel while the presence of syntaxin-3 did not. This AQP-syntaxin interaction agrees with the polarity of these proteins' expression in the inner medullary collecting duct epithelium. Thus our findings suggest a selectivity of interactions between different aquaporin and syntaxin isoforms, and thus in the regulation of AQP2 and AQP3 activities in the plasma membrane. Snapin plays an important role as a linker between the water channel and the t-SNARE complex, leading to the fusion event, and the pairing with specific t-SNAREs is essential for the specificity of membrane recognition and fusion.
Integration of the Reflex Pharyngeal Swallow Into Rhythmic Oral Activity in a Neurologically Intact Pig Model
Authors: German Rebecca Z. , Crompton A. W. , Thexton Allan J.
Published: June 2009

Mammalian swallowing involves the coordinated and sequential activity of many oropharyngeal muscles. Using synchronous electromyography (EMG) and videofluorography, we recorded the pattern of EMG activity for 12 muscles during swallowing in neurologically intact suckling pigs. We tested the hypothesis that this EMG pattern corresponded to the established pattern of activity for the isolated, reflexive pharyngeal swallow of the decerebrate infant pig. The EMG activity associated with the normal swallow of the intact animal had two components: a staggered pattern of single EMG bursts that were prominent in the stylohyoid, thyrohyoid, cricothyroid, and omohyoid muscles and double bursts of activity in some muscles, including geniohyoid and genioglossus, with the same underlying periodicity as suckling. Most of the staggered activity pattern, a linear sequence of progressively delayed activities in different muscles, was not statistically different from that previously found in the reflexive pharyngeal swallow of the decerebrate. However, not all components of the linear sequence of the reflexive swallow were inserted unchanged into the intact swallow. Some components appeared to be delayed or advanced, bringing them into phase with the underlying rhythmic activity. The difference between swallows of intact and of decerebrate animals was not solely due to the presence of rhythmic activity in the former. The timing of some EMG activities in intact animals also differed from the same activities in the few decerebrates that exhibited rhythmic tongue and jaw activity. These results suggest cerebral function influences the EMG pattern of the pharyngeal swallow, which has traditionally been considered a purely reflex pattern.
Isoflurane Inhibits the Neurotransmitter Release Machinery
Authors: Herring Bruce E. , Xie Zheng , Marks Jeremy , Fox Aaron P.
Published: June 2009

Despite their importance, the mechanism of action of general anesthetics is still poorly understood. Facilitation of inhibitory GABAAreceptors plays an important role in anesthesia, but other targets have also been linked to anesthetic actions. Anesthetics are known to suppress excitatory synaptic transmission, but it has been difficult to determine whether they act on the neurotransmitter release machinery itself. By directly elevating [Ca2+]iat neurotransmitter release sites without altering plasma membrane channels or receptors, we show that the commonly used inhalational general anesthetic, isoflurane, inhibits neurotransmitter release at clinically relevant concentrations, in a dose-dependent fashion in PC12 cells and hippocampal neurons. We hypothesized that a SNARE and/or SNARE-associated protein represents an important target(s) for isoflurane. Overexpression of a syntaxin 1A mutant, previously shown in Caenorhabditis elegans to block the behavioral effects of isoflurane, completely eliminated the reduction in neurotransmitter release produced by isoflurane, without affecting release itself, thereby establishing the possibility that syntaxin 1A is an intermediary in isoflurane's ability to inhibit neurotransmitter release.
Risky Business: Disambiguating Ambiguity-Related Responses in the Brain
Authors: O'Neill Martin , Kobayashi Shunsuke
Published: June 2009

Previous functional MRI studies reported neural correlates of risk and ambiguity based on behavioral economic theories. A recent study controlled for uncertainty by adding noise to information of an impending aversive event and demonstrated brain areas that did not track the degree of uncertainty: the activation peaked when the degraded information could be restored by cognitive efforts. In this review, we discuss how the variables defined in economics and cognitive psychology frameworks can be dissociated.
Synaptic Linkages Between Corticomotoneuronal Cells Affecting Forelimb Muscles in Behaving Primates
Authors: Smith W. S. , Fetz E. E.
Published: June 2009

To elucidate the cortical circuitry controlling primate forelimb muscles we investigated the synaptic interactions between neighboring motor cortex cells that had postspike output effects in target muscles. In monkeys generating isometric ramp-and-hold wrist torques, pairs of cortical cells were recorded simultaneously with independent electrodes and corticomotoneuronal (“CM”) cells were identified by their postspike effects on target forelimb muscles in spike-triggered averages (SpTAs) of electromyographs (EMGs). The response patterns of the cells were determined in response-aligned averages and their synaptic interactions were identified by cross-correlograms of action potentials. The possibility that synchronized firing between cortical cells could mediate spike-correlated effects in the SpTA of EMG was examined in several ways. Sixty-two pairs consisted of one CM cell and a non-CM cell; 15 of these had correlogram peaks of the same magnitude as that of other pairs, but the synchrony peaks did not mediate any postspike effect from the non-CM cell. Twelve pairs of simultaneously recorded CM cells were cross-correlated. Half had features (usually synchrony peaks) in their cross-correlograms and the cells of these pairs also shared some target muscles in common. The other half had flat correlograms and, in most of these pairs, the CM cells affected different muscles. The latter group included pairs of CM cells that facilitated synergistic muscles. These results indicate that common synaptic input specifically affects CM cells that have overlapping muscle fields. Reconstruction of the cortical locations of CM cells affecting 12 different muscles showed a wide and overlapping distribution of cortical colonies of forelimb muscles.
Pharmacological Analysis of Tonic Activity in Motoneurons During Stick Insect Walking
Authors: Westmark Sandra , Oliveira Eugenio E. , Schmidt Joachim
Published: June 2009

Stick insect middle leg (mesothoracic) motoneurons receive tonic excitatory input during front leg stepping on a treadmill. We studied the pharmacology of this excitatory input to the motoneurons during single-legged treadmill walking (in situ). During bath application of drugs restricted to the mesothoracic ganglion, activity in motoneurons contralateral to the stepping front leg was recorded from neuropilar processes. Application of the cholinergic antagonist atropine reduced the tonic depolarization amplitude. These results were compared with findings in acutely dissociated motoneuron cell bodies (in vitro) under whole cell voltage-clamp conditions. The presence of an acetylcholine-induced current in situ was supported by the finding of an acetylcholine evoked biphasic inward current with a sustained component that could be blocked by atropine. In situ the tonic depolarization was generally increased by application of the neuro-modulator octopamine and decreased by its antagonist mianserin. In vitro, however, octopamine reduced the inward current evoked by acetylcholine application to motoneurons. Intracellular application of bis-( o-aminophenoxy)- N,N,N',N'-tetraacetic acid (BAPTA) into motoneurons in situ revealed a dependence of the tonic depolarization on Ca2+and application of the membrane-permeable cAMP analogue 8-bromo-cAMP increased the tonic depolarization. In contrast, 8-bromo-cAMP reduced the inward current evoked by acetylcholine application to motoneurons in vitro. We conclude that during walking, acetylcholine contributes to mediating the tonic depolarization possibly by acting on atropine-sensitive receptors on motoneurons. Octopamine that is released during walking increases the tonic depolarization. This increase, however, is not based on modulation of cholinergic action on motoneurons but rather on effects on premotor neurons. Both, Ca2+and cAMP are likely second messengers involved in mediating the tonic depolarization, but whereas Ca2+acts in motoneurons, cAMP does not appear to mediate a cholinergic depolarization in motoneurons.
An Improved Ensemble Method for Completely Automatic Optimization of Spectral Interval Selection in Multivariate Calibration
Authors: Yu Xiao-Ping , Xu Lu , Yu Ru-Qin
Published: June 2009

In our recent work, Monte Carlo Cross Validation Stacked Regression (MCCVSR) is proposed to achieve automatic optimization of spectral interval selection in multivariate calibration. Though MCCVSR performs well in normal conditions, it is still necessary to improve it for more general applications. According to the well‐known principle of “garbage in, garbage out (GIGO)”, as a precise ensemble method, MCCVSR might be influenced by outlying and very bad submodels. In this paper, a statistical test is designed to exclude the ruinous submodels from the ensemble learning process, therefore, the combination process becomes more reliable. Though completely automated, the proposed method is adjustable according to the nature of the data analyzed, including the size of training samples, resolution of spectra and quantitative potentials of the submodels. The effectiveness of the submodel refining is demonstrated by the investigation of a real standard data.
Suicidal Ideation Induced by Episodic Cannabis Use
Authors: Raja Michele , Azzoni Antonella
Published: June 2009

The report describes a patient who presented suicidal ideation only in two different occasions, immediately after acute cannabis intoxication. He used cannabis only in these two circumstances. Although a definite association between cannabis use and suicidal ideation or behavior has been already reported in the literature, the described case presents two original clinical aspects that deserve consideration. First, episodic assumption of cannabis induced suicidal ideation abruptly. Second, suicidal ideation appeared independent of mood depression, stressors, or life events, suggesting that suicidality may be not a direct consequence of depression and appears to be a relatively independent psychopathological dimension. There seems to be no linear relation between the severity of depression and the risk of suicide.
Strong Convergence of an Iterative Method for Equilibrium Problems and Variational Inequality Problems
Authors: Li Hong Yu , Li Hong Zhi
Published: June 2009

We introduce an iterative method for finding a common element of the set of solutions of equilibrium problems, the set of solutions of variational inequality problems, and the set of fixed points of finite many nonexpansive mappings. We prove strong convergence of the iterative sequence generated by the proposed iterative algorithm to the unique solution of a variational inequality, which is the optimality condition for the minimization problem.
Rapid Diagnosis of Malaria
Authors: Murray Clinton K. , Bennett Jason W.
Published: June 2009

Malaria's global impact is expansive and includes the extremes of the healthcare system ranging from international travelers returning to nonendemic regions with tertiary referral medical care to residents in hyperendemic regions without access to medical care. Implementation of prompt and accurate diagnosis is needed to curb the expanding global impact of malaria associated with ever-increasing antimalarial drug resistance. Traditionally, malaria is diagnosed using clinical criteria and/or light microscopy even though both strategies are clearly inadequate in many healthcare settings. Hand held immunochromatographic rapid diagnostic tests (RDTs) have been recognized as an ideal alternative method for diagnosing malaria. Numerous malaria RDTs have been developed and are widely available; however, an assortment of issues related to these products have become apparent. This review provides a summary of RDT including effectiveness and strategies to select the ideal RDT in varying healthcare settings.
Over the Counter Availability of Antituberculosis Drugs in Tbilisi, Georgia in the Setting of a High Prevalence of MDR-TB
Authors: Kobaidze Ketevan , Salakaia Archil , Blumberg Henry M.
Published: June 2009

Georgia, a country of 4.5 million people, has a high incidence of tuberculosis (TB) including drug resistant cases. Easy access and inappropriate use of anti-TB drugs are risk factors for further development of multidrug resistant (MDR)-TB. We carried out an investigation to assess the availability of over the counter anti-TB agents in pharmacies in Tbilisi. During February 2006, 15 pharmacies were randomly selected and the pharmacist at each store was interviewed. We found that all anti-TB medications stocked by these pharmacies were available and sold without a prescription. All 15 pharmacies sold isoniazid, rifampicin, and streptomycin; 13 (87%) of 15 pharmacies also sold pyrazinamide, ethambutol. Second line anti-TB drugs such as amikacin and kanamycin (injectable agents) and older fluoroquinolones (ofloxacin and ciprofloxacin) were available at 13 pharmacies while newer generation fluoroquinolones were less available(3 sold leovofloxacin, none sold moxifloxacin). The ease access and availability of anti-TB agents is of a great concern given the high prevalence of TB including MDR-TB in Georgia. The potential for misuse of these anti-TB drugs can lead to the development of further drug resistance. These drugs should only be available by prescription in order to reduce the chance of amplifying drug resistance.
Performance Comparison of Reflector- and Planar-Antenna Based Digital Beam-Forming SAR
Authors: Younis Marwan , Huber Sigurd , Patyuchenko Anton , Bordoni Federica , Krieger Gerhard
Published: June 2009

The trend in the conception of future spaceborne radar remote sensing is clearly toward the use of digital beamforming techniques. These systems will comprise multiple digital channels, where the analog-to-digital converter is moved closer to the antenna. This dispenses the need for analog beam steering and by this the used of transmit/receive modules for phase and amplitude control. Digital beam-forming will enable Synthetic Aperture Radar (SAR) which overcomes the coverage and resolution limitations applicable to state-of-the-art systems. On the other hand, new antenna architectures, such as reflectors, already implemented in communication satellites, are being considered for SAR applications. An open question is the benefit of combining digital beam-forming techniques with reflector antennas. The paper answers this question by comparing the system architecture and digital beam-forming requirements of a planar and a reflector antenna SAR. Further elaboration yields the resulting SAR performance of both systems. This paper considers multiple novel aspects of digital beam-forming SAR system design, which jointly flow into the presented system performance.
A Hybrid Iterative Scheme for Equilibrium Problems, Variational Inequality Problems, and Fixed Point Problems in Banach Spaces
Authors: Cholamjiak Prasit
Published: June 2009

The purpose of this paper is to introduce a new hybrid projection algorithm for finding a common element of the set of solutions of the equilibrium problem and the set of the variational inequality for an inverse-strongly monotone operator and the set of fixed points of relatively quasi-nonexpansive mappings in a Banach space. Then we show a strong convergence theorem. Using this result, we obtain some applications in a Banach space.
Fixed Points of Multivalued Maps in Modular Function Spaces
Authors: Kutbi Marwan A. , Latif Abdul
Published: June 2009

The purpose of this paper is to study the existence of fixed points for contractive-type and nonexpansive-type multivalued maps in the setting of modular function spaces. We also discuss the concept of "Equation missing"-modular function and prove fixed point results for weakly-modular contractive maps in modular function spaces. These results extend several similar results proved in metric and Banach spaces settings.
Transmission Performance Analysis of Fiber Optical Parametric Amplifiers for WDM System
Authors: Jiang Xiaohong , Jiang Chun
Published: June 2009

A numerical analysis is presented on the long-haul wavelength-division multiplexing (WDM) transmission system employing fiber-optic parametric amplifier (FOPA) cascades based on one-pump FOPA model with Raman Effect taken into account. The end-to-end equalization scheme is applied to optimize the system features in terms of proper output powers and signal-to-noise ratios (SNRs) in all the channels. The numerical results show that—through adjusting the fiber spans along with the number of FOPAs as well as the channel powers at the terminals in a prescribed way—the transmission distance and system performance can be optimized. By comparing the results generated by different lengths of fiber span, we come to the optimal span length to achieve the best transmission performance. Furthermore, we make a comparison among the long-haul WDM transmission systems employing different inline amplifiers, namely, FOPA, erbium-doped fiber amplifier (EDFA), and Fiber Raman Amplifier (FRA). FOPA demonstrates its advantage over the other two in terms of system features.
The Ottoman Monetary Crisis of 1585 Revisited
Authors: Tezcan Baki
Published: June 2009

In 1585-8, the Ottoman silver currency, the akçe, was officially devalued by 100% against the Venetian gold ducat and foreign silver currencies, and its silver content was reduced by 44%. Some scholars have interpreted this devaluation and debasement as a consequence of the silver influx from the Americas, whereas others have referred to the difficulties that the Ottoman state had to face in financing its war effort against the Safavids in Persia. This study suggests that the unification of a number of distinct regional monetary zones in an interregional imperial economy by the second half of the sixteenth century must be regarded as an important factor that contributed to the monetary crisis of 1585. En 1585-88, l'akçe, la monnaie d'argent ottomane, fut dévaluée officiellement de 100% par rapport au ducat d'or vénitien et les monnaies d'argent étrangères, et le pourcentage d'argent en fut réduit de 44%. Certains chercheurs interprètent cette dévaluation et cette dépréciation comme étant la conséquence de l'influx d'argent venant des Amériques, tandisque d'autres attribuent les problèmes de l'état ottoman au financement des guerres contre les Safavides d'Iran. Cette contribution suggère que l'unification d'un bon nombre de zones monétaires régionales qui différaient entre elles en une seule économie impériale interrégionale dans la seconde moitié du XVIe siècle doit être regardée comme un facteur important ayant contribué à la crise monétaire de 1585.
Migrants and Mutineers: The Rebellion of Kong Youde and Seventeenth-Century Northeast Asia
Authors: Agnew Christopher
Published: June 2009

This article analyzes the 1631-33 mutiny led by Kong Youde against the Ming state on the Shandong peninsula and argues that the conflict emerged directly out of the social tensions between local populations and the displaced migrant refugees of the Bohai gulf region. The maritime integration of the Shandong coast city of Dengzhou with the commercial networks of the Liaodong peninsula and the island archipelagoes of the Bohai, together with the militarization of this regional space, created the social conditions in which Kong Youde could mobilize migrant discontent and attempt to construct his own independent military regime. Cette contribution examine la révolte de 1631-1633 dans la presqu'île de Shantung (Shangdong) mené par Kong Youde contre l'Empire Ming. L'auteur estime que ce conflit est en rapport direct avec les tensions sociales entre les populations locales et des migrants déplacés, des réfugés de la région du Golfe de Bohai. D'une part l'intégration maritime de Dengzhou, ville cotière de Shantung avec les réseaux commerciaux de la presqu'île Liaodong, et d'autre part celle avec les archipels de Bohai, ainsi que la militarisation de la région en surcroît, créèrent des conditions sociales qui permîrent à Kong Youde de mobiliser des migrants mécontants qui lui servîrent dans son régime militaire indépendant prévu.
Improving SCIPUFF Dispersion Forecasts with NWP Ensembles
Authors: Lee Jared A. , Peltier L. Joel , Haupt Sue Ellen , Wyngaard John C. , Stauffer David R. , Deng Aijun
Published: June 2009

The relationships between atmospheric transport and dispersion (AT&D) plume uncertainty and uncertainties in the transporting wind fields are investigated using the Second-Order Closure, Integrated Puff (SCIPUFF) AT&D model driven by numerical weather prediction (NWP) meteorological fields. Modeled contaminant concentrations for episode 1 of the 1983 Cross-Appalachian Tracer Experiment (CAPTEX-83) are compared with recorded ground-level concentrations of the inert tracer gas C7F14. This study evaluates a Taylor-diffusion-based parameterization of dispersion uncertainty for SCIPUFF that uses Eulerian meteorological ensemble velocity statistics and a Lagrangian integral time scale as input. These values are diagnosed from NWP ensemble data. Individual simulations of the tracer release fail to reproduce some of the monitored surface concentrations of the tracer. The plumes that are predicted using the uncertainty model in SCIPUFF are broader, improving the overlap between the predicted and observed results. Augmenting the meteorological input to SCIPUFF with meteorological ensemble-uncertainty parameters therefore provides both a better estimate of the expected plume location and the relative uncertainties in the predicted concentrations than single deterministic forecasts. These results suggest that this new parameterization of NWP wind field uncertainty for dispersion may provide more sophisticated information that may benefit emergency response and decision making.
Mechanisms for Spontaneous Gravity Wave Generation within a Dipole Vortex
Authors: Snyder Chris , Plougonven Riwal , Muraki David J.
Published: June 2009

Previous simulations of dipole vortices propagating through rotating, stratified fluid have revealed small-scale inertia–gravity waves that are embedded within the dipole near its leading edge and are approximately stationary relative to the dipole. The mechanism by which these waves are generated is investigated, beginning from the observation that the dipole can be reasonably approximated by a balanced quasigeostrophic (QG) solution. The deviations from the QG solution (including the waves) then satisfy linear equations that come from linearization of the governing equations about the QG dipole and are forced by the residual tendency of the QG dipole (i.e., the difference between the time tendency of the QG solution and that of the full primitive equations initialized with the QG fields). The waves do not appear to be generated by an instability of the balanced dipole, as homogeneous solutions of the linear equations amplify little over the time scale for which the linear equations are valid. Linear solutions forced by the residual tendency capture the scale, location, and pattern of the inertia–gravity waves, although they overpredict the wave amplitude by a factor of 2. There is thus strong evidence that the waves are generated as a forced linear response to the balanced flow. The relation to and differences from other theories for wave generation by balanced flows, including those of Lighthill and Ford et al., are discussed.
A Wave Amplitude Transition in a Quasi-Linear Model with Radiative Forcing and Surface Drag
Authors: Lachmy Orli , Harnik Nili
Published: June 2009

A quasi-linear two-layer quasigeostrophic β-plane model of the interaction between a baroclinic jet and a single zonal wavenumber perturbation is used to study the mechanics leading to a wave amplitude bifurcation—in particular, the role of the critical surfaces in the upper-tropospheric jet flanks. The jet is forced by Newtonian heating toward a radiative equilibrium state, and Ekman damping is applied at the surface. When the typical horizontal scale is approximately the Rossby radius of deformation, the waves equilibrate at a finite amplitude that is comparable to the mean flow. This state is obtained as a result of a wave-induced temporary destabilization of the mean flow, during which the waves grow to their finite-equilibrium amplitude. When the typical horizontal scale is wider, the model also supports a state in which the waves equilibrate at negligible amplitudes. The transition from small to finite-amplitude waves, which occurs at weak instabilities, is abrupt as the parameters of the system are gradually varied, and in a certain range of parameter values both equilibrated states are supported.

The simple two-layer quasi-linear setting of the model allows a detailed examination of the temporary destabilization process inherent in the large-amplitude equilibration. As the waves grow they reduce the baroclinic growth by reducing the vertical shear of the mean flow, and reduce the barotropic decay by reducing the mean potential vorticity gradient at the inner sides of the upper-layer critical levels. Temporary destabilization occurs when the reduction in barotropic decay is larger than the reduction in baroclinic growth, leading to a larger total growth rate. Ekman friction and radiative damping are found to play a major role in sustaining the vertical shear of the mean flow and enabling the baroclinic growth to continue. By controlling the mean flow potential vorticity gradient near the critical level, the model evolution can be changed from one type of equilibration to the other.
Can a Convective Cloud Feedback Help to Eliminate Winter Sea Ice at High CO2 Concentrations?
Authors: Abbot Dorian S. , Walker Chris C. , Tziperman Eli
Published: June 2009

Winter sea ice dramatically cools the Arctic climate during the coldest months of the year and may have remote effects on global climate as well. Accurate forecasting of winter sea ice has significant social and economic benefits. Such forecasting requires the identification and understanding of all of the feedbacks that can affect sea ice.

A convective cloud feedback has recently been proposed in the context of explaining equable climates, for example, the climate of the Eocene, which might be important for determining future winter sea ice. In this feedback, CO2-initiated warming leads to sea ice reduction, which allows increased heat and moisture fluxes from the ocean surface, which in turn destabilizes the atmosphere and leads to atmospheric convection. This atmospheric convection produces optically thick convective clouds and increases high-altitude moisture levels, both of which trap outgoing longwave radiation and therefore result in further warming and sea ice loss.

Here it is shown that this convective cloud feedback is active at high CO2 during polar night in the coupled ocean–sea ice–land–atmosphere global climate models used for the 1% yr−1 CO2 increase to the quadrupling (1120 ppm) scenario of the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report. At quadrupled CO2, model forecasts of maximum seasonal (March) sea ice volume are found to be correlated with polar winter cloud radiative forcing, which the convective cloud feedback increases. In contrast, sea ice volume is entirely uncorrelated with model global climate sensitivity. It is then shown that the convective cloud feedback plays an essential role in the elimination of March sea ice at quadrupled CO2 in NCAR’s Community Climate System Model (CCSM), one of the IPCC models that loses sea ice year-round at this CO2 concentration. A new method is developed to disable the convective cloud feedback in the Community Atmosphere Model (CAM), the atmospheric component of CCSM, and to show that March sea ice cannot be eliminated in CCSM at CO2 = 1120 ppm without the aide of the convective cloud feedback.
An Analysis of Tropospheric Humidity Trends from Radiosondes
Authors: McCarthy Mark P. , Thorne P. W. , Titchner H. A.
Published: June 2009

A new analysis of historical radiosonde humidity observations is described. An assessment of both known and unknown instrument and observing practice changes has been conducted to assess their impact on bias and uncertainty in long-term trends. The processing of the data includes interpolation of data to address known sampling bias from missing dry day and cold temperature events, a first-guess adjustment for known radiosonde model changes, and a more sophisticated ensemble of estimates based on 100 neighbor-based homogenizations. At each stage the impact and uncertainty of the process has been quantified. The adjustments remove an apparent drying over Europe and parts of Asia and introduce greater consistency between temperature and specific humidity trends from day and night observations. Interannual variability and trends at the surface are shown to be in good agreement with independent in situ datasets, although some steplike discrepancies are apparent between the time series of relative humidity at the surface.

Adjusted trends, accounting for documented and undocumented break points and their uncertainty, across the extratropical Northern Hemisphere lower and midtroposphere show warming of 0.1–0.4 K decade−1 and moistening on the order of 1%–5% decade−1 since 1970. There is little or no change in the observed relative humidity in the same period, consistent with climate model expectation of a positive water vapor feedback in the extratropics with near-constant relative humidity.
New Efficient Sparse Space–Time Algorithms for Superparameterization on Mesoscales
Authors: Xing Yulong , Majda Andrew J. , Grabowski Wojciech W.
Published: June 2009

Superparameterization (SP) is a large-scale modeling system with explicit representation of small-scale and mesoscale processes provided by a cloud-resolving model (CRM) embedded in each column of a large-scale model. New efficient sparse space–time algorithms based on the original idea of SP are presented. The large-scale dynamics are unchanged, but the small-scale model is solved in a reduced spatially periodic domain to save the computation cost following a similar idea applied by one of the authors for aquaplanet simulations. In addition, the time interval of integration of the small-scale model is reduced systematically for the same purpose, which results in a different coupling mechanism between the small- and large-scale models. The new algorithms have been applied to a stringent two-dimensional test suite involving moist convection interacting with shear with regimes ranging from strong free and forced squall lines to dying scattered convection as the shear strength varies. The numerical results are compared with the CRM and original SP. It is shown here that for all of the regimes of propagation and dying scattered convection, the large-scale variables such as horizontal velocity and specific humidity are captured in a statistically accurate way (pattern correlations above 0.75) based on space–time reduction of the small-scale models by a factor of ⅓; thus, the new efficient algorithms for SP result in a gain of roughly a factor of 10 in efficiency while retaining a statistical accuracy on the large-scale variables. Even the models with ⅙ reduction in space–time with a gain of 36 in efficiency are able to distinguish between propagating squall lines and dying scattered convection with a pattern correlation above 0.6 for horizontal velocity and specific humidity. These encouraging results suggest the possibility of using these efficient new algorithms for limited-area mesoscale ensemble forecasting.
Connected to Birds but Not Bees: Valence Moderates Implicit Associations with Nature
Authors: Verges Michelle , Duffy Sean
Published: June 2009

The article discusses three experiments that replicated and extended prior research on implicit connections with built and natural environments. In Experiment I, participants classify “nature” (e.g., trees) and “self (e.g., me) items faster than “built” (e.g., factory) and “other” (e.g., them) items. This effect may attribute to words that elicit stronger positive associations to nature and stronger negative associations to built categories. In Experiment 2, participants rated nature and self items more positively than built and other items. This finding suggests a propensity to view oneself and the natural environment more favorably in comparison to others and the built environment This positive association to nature, however, was reversed in Experiment 3: Participants classify built and self items faster than nature and self items. Results indicate that stimulus valence moderates implicit associations to built and natural environments. Implications regarding the role of affective processing on implicit attitudes to these environments are discussed.
Hazard Proximity or Risk Perception? Evaluating Effects of Natural and Technological Hazards on Housing Values
Authors: Zhang Yang , Hwang Seong Nam , Lindell Michael K.
Published: June 2009

Despite the substantial literature on environmental hazards' effect on residential property value, the findings are inconsistent. Little attention has been given to the relationship between hazard proximity and risk perception and their distinct roles in affecting housing values. This research proposes a multistage causal model in which the influence of hazard proximity on property value is mediated by risk perception. The model was tested for three hazards (flood, hurricane, and toxic chemicals) using data from 321 households in Harris County, Texas. The results indicate that risk perception is a mediating factor between hazard proximity and property value, but there is some evidence that the mediation is partial rather than complete. Hazard proximity can be perceived as a potential risk and an environmental amenity at the same time for certain types of hazards. These two perceptions operate in opposite directions when affecting housing value. Implications for environmental hazards disclosure policies are discussed.
Defying Normative Male Identities: The Transgressive Possibilities of Jewish Boyhood
Authors: Reichert Michael C. , Ravitch Sharon M.
Published: June 2009

This qualitative study discovers teenage boys whose connections to Judaism and Jewish life offered them resilience and contextual opportunities for identity development. Those who have active, positive Jewish identities describe adaptations that are more independent of adolescent peer norms and freer, in terms of masculine pressures, than less Jewishly identified boys. Finding countercultural vitality in these boys’ masculine identities, reflecting their rootedness in community support, contributes to the understanding of male development on a number of levels. For the Jewish community, the study findings underscore how critically important culturally based connections can be for boys. In a world dominated by restrictive ideals for being male, a boy’s ability to consider alternatives is likely to depend on his relationships and access to other ecological resources. And for those hoping for a better world for boys, and for everyone else, these teens’ commitments convey the essential fact, that just as children cocreate childhood, boys can help to reinvent boyhood.