bluuebunny/crossref_metadata_2025 huggingface dataset:
The Subthalamic Nucleus in Primary Dystonia: Single-Unit Discharge Characteristics
Authors: Schrock Lauren E. , Ostrem Jill L. , Turner Robert S. , Shimamoto Shoichi A. , Starr Philip A.
Published: October 2009

Most models of dystonia pathophysiology predict alterations of activity in the basal ganglia thalamocortical motor circuit. The globus pallidus interna (GPi) shows bursting and oscillatory neuronal discharge in both human dystonia and in animal models, but it is not clear which intrinsic basal ganglia pathways are implicated in this abnormal output. The subthalamic nucleus (STN) receives prominent excitatory input directly from cortical areas implicated in dystonia pathogenesis and inhibitory input from the external globus pallidus. The goal of this study was to elucidate the role of the STN in dystonia by analyzing STN neuronal discharge in patients with idiopathic dystonia. Data were collected in awake patients undergoing microelectrode recording for implantation of STN deep brain stimulation electrodes. We recorded 62 STN neurons in 9 patients with primary dystonia. As a comparison group, we recorded 143 STN neurons in 20 patients with Parkinson's disease (PD). Single-unit activity was discriminated off-line by principal component analysis and evaluated with respect to discharge rate, bursting, and oscillatory activity. The mean STN discharge rate in dystonia patients was 26.3 Hz (SD 13.6), which was lower than that in the PD patients (35.6 Hz, SD 15.2), but higher than published values for subjects without basal ganglia dysfunction. Oscillatory activity was found in both disorders, with a higher proportion of units oscillating in the beta range in PD. Bursting discharge was a prominent feature of both dystonia and PD, whereas sensory receptive fields were expanded in PD compared with dystonia. The STN firing characteristics, in conjunction with those previously published for GPi, suggest that bursting and oscillatory discharge in basal ganglia output may be transmitted via pathways involving the STN and provide a pathophysiologic rationale for STN as a surgical target in dystonia.
Slow Excitation of Cultured Rat Retinal Ganglion Cells by Activating Group I Metabotropic Glutamate Receptors
Authors: Yu Jianing , Daniels Bryan A. , Baldridge William H.
Published: October 2009

As in many CNS neurons, retinal ganglion cells (RGCs) receive fast synaptic activation through postsynaptic ionotropic receptors. However, the potential role of postsynaptic group I metabotropic glutamate receptors (mGluRs) in these neurons is unknown. In this study we first demonstrated that the selective group I mGluR agonist ( S)-3,5-dihydroxyphenylglycine (DHPG) increased intracellular calcium concentration in neurons within the ganglion cell layer of the rat retina. This prompted us to use an immunopanned-RGC and cortical astroglia coculture preparation to explore the effect of group I mGluR activation on the electrophysiological properties of cultured RGCs. Using perforated patch-clamp recordings in current-clamp configuration, we found that application of DHPG increased spontaneous spiking and depolarized the resting membrane potential of RGCs. This boosting effect was attributed to an increase in membrane resistance due to blockade of a background K+ conductance. Further experiments showed that the group I mGluR-sensitive K+ conductance was not blocked by 3 mM Cs+, but was sensitive to acidification. Pharmacological studies indicated that the effect of DHPG on RGCs was mediated by the mGluR1 rather than the mGluR5 receptor subtype. Our results suggest a facilitatory role for group I mGluR activation in modulating RGC excitability in the mammalian inner retina.
Altered GABAA,slowInhibition and Network Oscillations in Mice Lacking the GABAAReceptor β3Subunit
Authors: Hentschke Harald , Benkwitz Claudia , Banks Matthew I. , Perkins Mark G. , Homanics Gregg E. , Pearce Robert A.
Published: October 2009

Phasic GABAergic inhibition in hippocampus and neocortex falls into two kinetically distinct categories, GABAA,fastand GABAA,slow. In hippocampal area CA1, GABAA,fastis generally believed to underlie gamma oscillations, whereas the contribution of GABAA,slowto hippocampal rhythms has been speculative. Hypothesizing that GABAAreceptors containing the β3subunit contribute to GABAA,slowinhibition and that slow inhibitory synapses control excitability as well as contribute to network rhythms, we investigated the consequences of this subunit's absence on synaptic inhibition and network function. In pyramidal neurons of GABAAreceptor β3subunit-deficient (β3−/−) mice, spontaneous GABAA,slowinhibitory postsynaptic currents (IPSCs) were much less frequent, and evoked GABAA,slowcurrents were much smaller than in wild-type mice. Fittingly, long-lasting recurrent inhibition of population spikes was less powerful in the mutant, indicating that receptors containing β3subunits contribute substantially to GABAA,slowcurrents in pyramidal neurons. By contrast, slow inhibitory control of GABAA,fast-producing interneurons was unaffected in β3−/−mice. In vivo hippocampal network activity was markedly different in the two genotypes. In β3−/−mice, epileptiform activity was observed, and theta oscillations were weaker, slower, less regular and less well coordinated across laminae compared with wild-type mice, whereas gamma oscillations were weaker and faster. The amplitude modulation of gamma oscillations at theta frequency (“nesting”) was preserved but was less well coordinated with theta oscillations. With the caveat that seizure-induced changes in inhibitory circuits might have contributed to the changes observed in the mutant animals, our results point to a strong contribution of β3subunits to slow GABAergic inhibition onto pyramidal neurons but not onto GABAA,fast-producing interneurons and support different roles for these slow inhibitory synapses in the generation and coordination of hippocampal network rhythms.
Motor Outputs in a Multitasking Network: Relative Contributions of Inputs and Experience-Dependent Network States
Authors: Friedman Allyson K. , Zhurov Yuriy , Ludwar Bjoern Ch. , Weiss Klaudiusz R.
Published: October 2009

Network outputs elicited by a specific stimulus may differ radically depending on the momentary network state. One class of networks states—experience-dependent states—is known to operate in numerous networks, yet the fundamental question concerning the relative role that inputs and states play in determining the network outputs remains to be investigated in a behaviorally relevant manner. Because previous work indicated that in the isolated nervous system the motor outputs of the Aplysia feeding network are affected by experience-dependent states, we sought to establish the behavioral relevance of these outputs. We analyzed the phasing of firing of radula opening motoneurons (B44 and B48) relative to other previously characterized motoneurons. We found that the overall pattern of motoneuronal firing corresponds to the phasing of movements during feeding behavior, thus indicating a behavioral relevance of network outputs. Previous studies suggested that network inputs act to trigger a response rather than to shape its characteristics, with the latter function being fulfilled by network states. We show this is an oversimplification. In a rested state, different inputs elicited distinct responses, indicating that inputs not only trigger but also shape the responses. However, depending on the combination of inputs and states, responses were either dramatically altered by the network state or were indistinguishable from those observed in the rested state. We suggest that the relative contributions of inputs and states are dynamically regulated and, rather than being fixed, depend on the specifics of states and inputs.
Influence of Saccade Efference Copy on the Spatiotemporal Properties of Remapping: A Neural Network Study
Authors: Keith Gerald P. , Blohm Gunnar , Crawford J. Douglas
Published: October 2009

Remapping of gaze-centered target-position signals across saccades has been observed in the superior colliculus and several cortical areas. It is generally assumed that this remapping is driven by saccade-related signals. What is not known is how the different potential forms of this signal (i.e., visual, visuomotor, or motor) might influence this remapping. We trained a three-layer recurrent neural network to update target position (represented as a “hill” of activity in a gaze-centered topographic map) across saccades, using discrete time steps and backpropagation-through-time algorithm. Updating was driven by an efference copy of one of three saccade-related signals: a transient visual response to the saccade-target in two-dimensional (2-D) topographic coordinates ( Vtop), a temporally extended motor burst in 2-D topographic coordinates ( Mtop), or a 3-D eye velocity signal in brain stem coordinates ( EV). The Vtop model produced presaccadic remapping in the output layer, with a “jumping hill” of activity and intrasaccadic suppression. The Mtop model also produced presaccadic remapping with a dispersed moving hill of activity that closely reproduced the quantitative results of Sommer and Wurtz. The EV model produced a coherent moving hill of activity but failed to produce presaccadic remapping. When eye velocity and a topographic (Vtop or Mtop) updater signal were used together, the remapping relied primarily on the topographic signal. An analysis of the hidden layer activity revealed that the transient remapping was highly dispersed across hidden-layer units in both Vtop and Mtop models but tightly clustered in the EV model. These results show that the nature of the updater signal influences both the mechanism and final dynamics of remapping. Taken together with the currently known physiology, our simulations suggest that different brain areas might rely on different signals and mechanisms for updating that should be further distinguishable through currently available single- and multiunit recording paradigms.
The Use of Imatinib Mesylate as a Lifesaving Treatment of Chronic Myeloid Leukemia Relapse after Bone Marrow Transplantation
Authors: Conchon Monika , Sanabani Sabri S. , Bendit Israel , Dinardo Carla Luana , Dias Lucia , Chamone Dalton de Alencar Fischer , Dorlhiac-Llacer Pedro Enrique , Dulley Frederico Luiz
Published: October 2009

We describe the response of imatinib as lifesaving treatment of chronic myeloid leukemia (CML) relapse in seven patients who underwent allogeneic bone marrow transplantation (alloBMT) at our institution over a period of 4 years. Retrospective analysis of their medical records revealed that a mean age at transplant was 45.2 years. The median time to diagnosis was 7.4 years after transplant. At relapse, four, two, and one patients were classified as having hematologic, major molecular, and cytogenetic relapse, respectively. At imatinib initiation, five had CML in a chronic phase, while one patient was diagnosed as having accelerated phase and blast crisis. All these patients could be evaluated for the therapeutic efficacy. At a mean of follow-up of 1.9 years of therapy, all evaluable patients achieved major molecular response without compromising safety. Consistent with available data, our results indicate that imatinib is safe and effective treatment option for patients with relapse after BMT.
An Exon-Based Comparative Variant Analysis Pipeline to Study the Scale and Role of Frameshift and Nonsense Mutation in the Human-Chimpanzee Divergence
Authors: Yu GongXin
Published: October 2009

Chimpanzees and humans are closely related but differ in many deadly human diseases and other characteristics in physiology, anatomy, and pathology. In spite of decades of extensive research, crucial questions about the molecular mechanisms behind the differences are yet to be understood. Here I reportExonVar, a novel computational pipeline forExon-based human-chimpanzee comparativeVariant analysis. The objective is to comparatively analyze mutations specifically those that caused the frameshift and nonsense mutations and to assess their scale and potential impacts on human-chimpanzee divergence. Genomewide analysis of human and chimpanzee exons withExonVaridentified a number of species-specific, exon-disrupting mutations in chimpanzees but much fewer in humans. Many were found on genes involved in important biological processes such as T cell lineage development, the pathogenesis of inflammatory diseases, and antigen induced cell death. A “less-is-more” model was previously established to illustrate the role of the gene inactivation and disruptions during human evolution. Here this analysis suggested a different model where the chimpanzee-specific exon-disrupting mutations may act as additional evolutionary force that drove the human-chimpanzee divergence. Finally, the analysis revealed a number of sequencing errors in the chimpanzee and human genome sequences and further illustrated that they could be corrected without resequencing.
Characteristics of Community-Associated Methicillin-ResistantStaphylococcus aureus(CA-MRSA) Strains Isolated from Skin and Soft-Tissue Infections in Uruguay
Authors: Pardo Lorena , Machado Virginia , Mollerach Marta , Mota María Inés , Tuchscherr Lorena P. N. , Gadea Pilar , Gardella Noella , Sordelli Daniel O. , Vola Magdalena , Schelotto Felipe , Varela Gustavo
Published: October 2009

We analyzed 90 nonduplicates community-associated methicillin-resistantS. aureus(CA-MRSA) strains isolated from skin and soft-tissue infections. All strains weremecApositive. Twenty-four of the 90 strains showed inducible macrolide-lincosamide-streptogramin B resistance. All strains producedα-toxin; 96% and 100% of them displayed positive results forlukS-Fandcnagenes, respectively. Eigthy-five strains expressed capsular polysaccharide serotype 8. Six different pulsotypes were discriminated by pulsed-field gel electrophoresis (PFGE) and three predominant groups of CA-MRSA strains (1, 2, and 4) were identified, in agreement with phenotypic and genotypic characteristics. Strains of group 1 (pulsotype A, CP8+, and Panton-Valentine leukocidin (PVL)+) were the most frequently recovered and exhibited a PFGE band pattern identical to other CA-MRSA strains previously isolated in Uruguay and Brazil. Three years after the first local CA-MRSA report, these strains are still producing skin and soft-tissue infections demonstrating the stability over time of this community-associated emerging pathogen.
Benefit of Whole Pelvic Radiotherapy Combined with Neoadjuvant Androgen Deprivation for the High‐Risk Prostate Cancer
Authors: Milecki Piotr , Baczyk Maciej , Skowronek Janusz , Antczak Andrzej , Kwias Zbigniew , Martenka Piotr
Published: October 2009

Aim. To study
whether use of neoadjuvant androgen deprivation
therapy (N‐ADT) combined with whole pelvic
radiotherapy (WPRT) for high‐risk prostate
cancer patients was associated with survival
benefit over prostate radiotherapy (PORT) only.
Material and Methods. Between 1999 and 2004, 162
high‐risk prostate cancer patients were treated with radiotherapy
combined with long‐term androgen deprivation therapy (L‐ADT).
Patients were prospectively assigned into two groups: A (N‐ADT +
WPRT + L‐ADT) n = 70 pts, B (PORT + L‐ADT) n = 92 pts.
Results. The 5‐year actuarial overall survival
(OS) rates were 89% for A and 78% for B (P = .13). The 5‐year actuarial cause specific survival (CSS) rates were A = 90% and B = 79% (P = .01). Biochemical progression‐free survival (bPFS) rates were 52% versus 40% (P = .07), for groups A and B, respectively.
Conclusions. The WPRT combined with N‐ADT
compared to PORT for high‐risk patients resulted in improvement in
CSS and bPFS; however no OS benefit was observed.
Two Cases of Retroperitoneal Liposarcoma Diagnosed Using Endoscopic Ultrasound-Guided Fine-Needle Aspiration (EUS-FNA)
Authors: Takahashi Yuta , Irisawa Atsushi , Bhutani Manoop S. , Hikichi Takuto , Takagi Tadayuki , Shibukawa Goro , Wakatsuki Takeru , Imamura Hidemichi , Sato Ai , Sato Masaki , Ikeda Tsunehiko , Suzuki Rei , Obara Katsutoshi , Hashimoto Yuko , Watanabe Kazuo , Ohira Hiromasa
Published: October 2009

This report describes our experience with two cases that were ultimately diagnosed as retroperitoneal liposarcoma using endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Case 1 is that of a 54-year-old woman with chief complaints of nausea and abdominal distention. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a large (15 cm diameter) tumor, which was significantly compressing the stomach and apparently occupied the entire left abdominal cavity. Although advanced primary gastrointestinal stromal tumor (GIST) or retroperitoneal tumor was inferred as the differential diagnosis, a definitive diagnosis was difficult using imaging alone. After EUS-FNA was done, the tumor was diagnosed histopathologically as high-grade liposarcoma. Case 2 is that of a 73-year-old man. Abdominal ultrasonography and CT showed a 6 cm diameter tumor within the pelvic cavity. The tumor had high MRI signal-intensity on both T1 and T2 images. Endorectal EUS showed a hyperechoic mass. The images suggested lipoma or liposarcoma containing lipoma-like components. Myxoid liposarcoma was revealed by subsequent EUS-FNA. Performing EUS-FNA was clinically useful for determining the subsequent therapeutic strategy in these cases where a tumor of unknown origin existed in the retroperitoneum.
Dynamic Stability of Cylindrical Shells under Moving Loads by Applying Advanced Controlling Techniques—Part II: Using Piezo‐Stack Control
Authors: Eldalil Khaled M. Saadeldin , Baz Amr M. S.
Published: October 2009

The load acting on the actively controlled cylindrical shell under a transient pressure pulse propelling a moving mass (gun case) has been experimentally studied. The concept of using piezoelectric stack and stiffener combination is utilized for damping the tube wall radial and circumferential deforming vibrations, in the correct meeting location timing of the moving mass. The experiment was carried out by using the same stiffened shell tube of the experimental 14 mm gun tube facility which is used in part 1. Using single and double stacks is tried at two pressure levels of low‐speed modes, which have response frequencies adapted with the used piezoelectric stacks characteristics. The maximum active damping ratio is occurred at high‐pressure level. The radial circumferential strains are measured by using high‐frequency strain gage system in phase with laser beam detection system similar to which used in part 1. Time resolved strain measurements of the wall response were obtained, and both precursor and transverse hoop strains have been resolved. A complete comparison had been made between the effect of active controlled and stepped structure cases, which indicate a significant attenuation ratio especially at higher operating pressures.
Time-Resolved Spectroscopy Diagnostic of Laser-Induced Optical Breakdown
Authors: Parigger Christian G. , Hornkohl James O. , Nemes László
Published: October 2009

Transient laser plasma is generated in laser-induced optical breakdown (LIOB). Here we report experiments conducted with 10.6-micron CO2 laser radiation, and with 1.064-micron fundamental, 0.532-micron frequency-doubled, 0.355-micron frequency-tripled Nd:YAG laser radiation. Characterization of laser induced plasma utilizes laser-induced breakdown spectroscopy (LIBS) techniques. Atomic hydrogen Balmer series emissions show electron number density of 1017 cm−3 measured approximately 10 μs and 1 μs after optical breakdown for CO2 and Nd:YAG laser radiation, respectively. Recorded molecular recombination emission spectra of CN and C2 Swan bands indicate an equilibrium temperature in excess of 7000 Kelvin, inferred for these diatomic molecules. Reported are also graphite ablation experiments where we use unfocused laser radiation that is favorable for observation of neutral C3 emission due to reduced C3 cation formation. Our analysis is based on computation of diatomic molecular spectra that includes accurate determination of rotational line strengths, or Hönl-London factors.
Serotonergic mechanisms enhance platelet-mediated thrombogenicity
Authors: Lopez-Vilchez Irene , Diaz-Ricart Maribel , Navalon Fulgencio , Gomez Esther , Gasto Cristobal , Escolar Gines , Galan Ana M.
Published: October 2009

Although it is generally acknowledged that serotonin (5-HT) is a weak agonist for human platelets, recent information suggests an association between serotonergic mechanisms and cardiovascular risk. We investigated the action of 5-HT on adhesive, cohesive and procoagulant properties of human platelets. Impact of 5-HT on whole blood coagulation and thrombin generation was measured by modified thromboelastometry (TEM) and specific fluorogenic assays. We evaluated the effects of 5-HT on thrombus formation in an in-vitro model of thrombosis using human flowing blood. In platelet-rich plasma (PRP), 5-HT favoured the expression of CD62-P, and procoagulant molecules on platelet membranes. These effects were potentiated in the presence of Ca++ and/or ADP. Incubation with 5-HT accelerated clotting times and augmented clot strength in whole blood TEM, and enhanced thrombin generation in PRP. In perfusion studies, 5-HT significantly increased fibrin deposition at low shear (300s-1) and enhanced platelet thrombus formation on the damaged vascular surface at high shear (1,200s-1). Selective inhibition of serotonin reuptake (SSRI) attenuated effects of 5-HT on platelet activation and downregulated the prothrombotic tendencies observed in the previous experimental conditions. In general, reductions of thrombogenic patterns observed with SSRI were more evident under shear conditions (aggregation and perfusion systems) and less evident under steady conditions (TEM and thrombin generation assays). In conclusion, 5-HT is not a weak agonist for human platelets; instead it accentuates platelet activation, potentiates procoagulant responses on human blood and increases thrombogenesis on damaged vascular surfaces. The remarkable antithrombotic actions achieved through SSRI deserve further mechanistic and clinical investigations.
The Emerging Characterization of Lysine Residue Deacetylation on the Modulation of Mitochondrial Function and Cardiovascular Biology
Authors: Lu Zhongping , Scott Iain , Webster Bradley R. , Sack Michael N.
Published: October 2009

Abstract
:

There is emerging recognition of a novel fuel and redox sensing regulatory program that controls cellular adaptation via nonhistone protein lysine residue acetyl posttranslation modifications. This program functions in tissues with high energy demand and oxidative capacity and is highly enriched in the heart. Deacetylation is regulated by NAD
+
-dependent activation of the sirtuin family of proteins, whereas acetyltransferase modifications are controlled by less clearly delineated acetyltransferases. Subcellular localization specific protein targets of lysine-acetyl modification have been identified in the nucleus, cytoplasm, and mitochondria. Despite distinct subcellular localizations, these modifications appear, in large part, to modify mitochondrial properties including respiration, energy production, apoptosis, and antioxidant defenses. These mitochondrial regulatory programs are important in cardiovascular biology, although how protein acetyl modifications effects cardiovascular pathophysiology has not been extensively explored. This review will introduce the role of nonhistone protein lysine residue acetyl modifications, discuss their regulation and biochemistry and present the direct and indirect data implicating their involvement in the heart and vasculature.
Vegetation Control in the Long-Term Self-Stabilization of the Liangzhou Oasis of the Upper Shiyang River Watershed of West-Central Gansu, Northwest China
Authors: Bourque Charles P-A. , Hassan Quazi K.
Published: October 2009

This paper explores the relationship between vegetation in the Liangzhou Oasis in the Upper Shiyang River watershed (USRW) of west-central Gansu, China, and within-watershed precipitation, soil water storage, and oasis self-support. Oases along the base of the Qilian Mountains receive a significant portion of their water supply (over 90%) from surface and subsurface flow originating from the Qilian Mountains. Investigation of vegetation control on oasis water conditions in the USRW is based on an application of a process model of soil water hydrology. The model is used to simulate long-term soil water content (SWC) in the Liangzhou Oasis as a function of (i) monthly composites of Moderate Resolution Imaging Spectroradiometer (MODIS) images of land surface and mean air temperature, (ii) spatiotemporal calculations of monthly precipitation and relative humidity generated with the assistance of genetic algorithms (GAs), and (iii) a 80-m-resolution digital elevation model (DEM) of the area. Modeled removal of vegetation is shown to affect within-watershed precipitation and soil water storage by reducing the exchange of water vapor from the land surface to the air, increasing the air’s lifting condensation level by promoting drier air conditions, and causing the high-intensity precipitation band in the Qilian Mountains to weaken and to be displaced upward, leading to an overall reduction of water to the Liangzhou Oasis.
Southeast Pacific Stratocumulus: High-Frequency Variability and Mesoscale Structures over San Félix Island
Authors: Painemal David , Garreaud René , Rutllant José , Zuidema Paquita
Published: October 2009

Stratocumulus cloud cover patterns and their relationship to drizzle were characterized at San Felix Island (SFI; 26.5°S, 80°W) in the southeast Pacific Ocean. Small closed, large closed, and open cells were identified in about 65% of the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images during 2003. The MODIS imagery was combined with ceilometer and surface meteorological measurements, human observations of cloud types and drizzle, and large-scale meteorological analyses for January through June. The authors identified two drizzle regimes: a synoptically quiescent summer (January–March) regime characterized by a strong anticyclone, large closed cells, and frequent drizzle, and an autumn (April–June) regime characterized by a weaker anticyclone, small closed cells and open cells, and precipitation that was mainly associated with synoptic activity. The large closed cells had higher mean cloud bases and tops than the small closed cells and accounted for 45% of the cumulus-under-stratocumulus reports and 29% of the total drizzle and rain reports. Large closed cells occupied more intermittently coupled boundary layers than did the small closed cells. Open cells also occurred in more decoupled conditions but only accounted for 18% of the total reports of drizzle and rain. The atmospheric stability of large and small closed cells was similar, but large closed cells were more commonly associated with a strong anticyclone, and small closed cells with wave activity superimposed upon a weakened anticyclone. The increased drizzle and occurrence of cumulus-under-stratocumulus in the summer rather than autumn is consistent with higher nighttime liquid water paths. A contribution of this study is the documentation of the ways in which synoptic activity can affect stratocumulus decks.
A Technique to Censor Biological Echoes in Radar Reflectivity Data
Authors: Lakshmanan Valliappa , Zhang Jian , Howard Kenneth
Published: October 2009

Existing techniques of quality control of radar reflectivity data rely on local texture and vertical profiles to discriminate between precipitating echoes and nonprecipitating echoes. Nonprecipitating echoes may be due to artifacts such as anomalous propagation, ground clutter, electronic interference, sun strobe, and biological contaminants (i.e., birds, bats, and insects). The local texture of reflectivity fields suffices to remove most artifacts, except for biological echoes. Biological echoes, also called “bloom” echoes because of their circular shape and expanding size during the nighttime, have proven difficult to remove, especially in peak migration seasons of various biological species, because they can have local and vertical characteristics that are similar to those of stratiform rain or snow. In this paper, a technique is described that identifies candidate bloom echoes based on the range variance of reflectivity in areas of bloom and uses the global, rather than local, characteristic of the echo to discriminate between bloom and rain. Every range gate is assigned a probability that it corresponds to bloom using morphological (shape based) operations, and a neural network is trained using this probability as one of the input features. It is demonstrated that this technique is capable of identifying and removing echoes due to biological targets and other types of artifacts while retaining echoes that correspond to precipitation.
Global Circuit Model with Clouds
Authors: Zhou Limin , Tinsley Brian A.
Published: October 2009

Cloud data from the International Satellite Cloud Climatology Project (ISCCP) database have been introduced into the global circuit model developed by Tinsley and Zhou. Using the cloud-top pressure data and cloud type information, the authors have estimated the cloud thickness for each type of cloud. A treatment of the ion pair concentration in the cloud layer that depends on the radii and concentration of the cloud droplets is used to evaluate the reduction of conductivity in the cloud layer. The conductivities within typical clouds are found to be in the range of 2%–5% of that of cloud-free air at the same altitude, for the range of altitudes for typical low clouds to typical high clouds. The global circuit model was used to determine the increase in columnar resistance of each grid element location for various months in years of high and low volcanic and solar activity, taking into account the observed fractional cloud cover for different cloud types and thickness in each location. For a single 5° × 5° grid element in the Indian Ocean, for example, with the observed fractional cloud cover amounts for low, middle, and high clouds each near 20%, the ionosphere-to-surface column resistance increased by about 10%. (For 100%, fraction—that is, uniformly overcast conditions—for each of the cloud types, the increase depends on the cloud height and thickness and is about a factor of 10 for each of the lower-level clouds in this example and a factor of 2 for the cirrus cloud.) It was found that treating clouds, in the fraction of each grid element in which they were present, as having zero conductivity made very little difference to the results. The increase in global total resistance for the global ensemble of columns in the ionosphere–earth return path in the global circuit was about 10%, applicable to the several solar and volcanic activity conditions, but this is probably an upper limit, in light of the unavailability of data on subkilometer breaks in cloud cover.
Daily-Mean Temperature Reconstructed for Kansas from Early Instrumental and Modern Observations
Authors: Burnette Dorian J. , Stahle David W. , Mock Cary J.
Published: October 2009

A continuous record of 65 987 daily-mean temperature observations since 1828 has been developed for Manhattan, Kansas, by screening and correcting original station records of the U.S. Army Surgeon General, the Smithsonian Institution, and the Signal Service. Hourly, minimum, and maximum temperature observations from seven discontinuous historical stations and four modern stations in Kansas, Missouri, and Oklahoma were used to compile this unbroken record of daily-mean temperature. The historical temperature data were linked with the modern temperature record for Manhattan after these data were adjusted for time of observation differences, station movements, and changes in the environment around the station. The new daily-mean temperature reconstruction for Manhattan now extends with confidence back to 1 July 1855 and with more uncertainty back to 1 July 1828. The uncertainty prior to 1855 is due to instrumentation changes in 1843 and changes in observation practices in 1855 that occurred at many stations. The error estimates reported in this paper do not reflect these potential inhomogeneities and should be considered lower limits. Nonetheless, this new daily record indicates significant warming in all seasons; in heating and cooling degree-days; in the warmest and coldest days of the year; in extremes above the 90th percentile and below the 10th percentile; in the frequency of winter cold waves and summer heat waves; and in the overall annual-mean temperature, which has warmed by 1.57° ± 0.23°C since 1855 (1.27° ± 0.23°C since 1829). The warm Dust Bowl event in the summer of the 1930s and cold winters of the 1870s and 1880s dominate the reconstruction and included some of the warmest and coldest daily extremes, respectively, of the last 154–180 yr. This new reconstruction is currently the longest unbroken daily corrected record in the Americas. These data indicate that the nineteenth century was fundamentally cooler than the twentieth and early twenty-first century.
Hydrodynamics of the Caribbean Low-Level Jet and Its Relationship to Precipitation
Authors: Cook Kerry H. , Vizy Edward K.
Published: October 2009

The easterly Caribbean low-level jet (CLLJ) is a prominent climate feature over the Intra-America Seas, and it is associated with much of the water vapor transport from the tropical Atlantic into the Caribbean Basin. In this study, the North American Regional Reanalysis (NARR) is analyzed to improve the understanding of the dynamics of the CLLJ and its relationship to regional rainfall variations.

Horizontal momentum balances are examined to understand how jet variations on both diurnal and seasonal time scales are controlled. The jet is geostrophic to the first order. Its previously documented semidiurnal cycle (with minima at about 0400 and 1600 LT) is caused by semidiurnal cycling of the meridional geopotential height gradient in association with changes in the westward extension of the North Atlantic subtropical high (NASH). A diurnal cycle is superimposed, associated with a meridional land–sea breeze (solenoidal circulation) onto the north coast of South America, so that the weakest jet velocities occur at 1600 LT. The CLLJ is present throughout the year, and it is known to vary in strength semiannually. Peak magnitudes in July are related to the seasonal cycle of the NASH, and a second maximum in February is caused by heating over northern South America. From May through September, zonal geopotential gradients associated with summer heating over Central America and Mexico induce meridional flow. The CLLJ splits into two branches, including a southerly branch that connects with the Great Plains low-level jet (GPLLJ) bringing moisture into the central United States. During the rest of the year, the flow remains essentially zonal across the Caribbean Basin and into the Pacific.

A strong (weak) CLLJ is associated with reduced (enhanced) rainfall over the Caribbean Sea throughout the year in the NARR. The relationship with precipitation over land depends on the season. Despite the fact that the southerly branch of the CLLJ feeds into the meridional GPLLJ in May through September, variations in the CLLJ strength during these months do not impact U.S. precipitation, because the CLLJ strength is varying in response to regional-scale forcing and not to changes in the large-scale circulation. During the cool season, there are statistically significant correlations between the CLLJ index and rainfall over the United States. When the CLLJ is strong, there is anomalous northward moisture transport across the Gulf of Mexico into the central United States and pronounced rainfall increases over Louisiana and Texas. A weak jet is associated with anomalous westerly flow across the southern Caribbean region and significantly reduced rainfall over the south-central United States.

No connection between the intensity of the CLLJ and drought over the central United States is found. There are only three drought summers in the NARR period (1980, 1988, and 2006), and the CLLJ was extremely weak in 1988 but not in 1980 or 2006.
Analysis of Severe Rainstorm Characteristics of the Godavari Basin in Peninsular India
Authors: Kulkarni B. D. , Nandargi S. , Mulye S. S.
Published: October 2009

The analysis of rainstorms is of prime importance for the planning and design of water resources of any region. In the absence of actual records of streamflow data, analysis of rainstorms is useful for assessing flood potentialities as well as the runoff of river catchments. This study provides pertinent information on the spatial distribution characteristics of severe rainstorm events that occurred over the Godavari and its subbasins on the basis of 110 yr (1891–2000) of available rainfall data. The analysis showed that the August 1986 rainstorm had its areal extension over more than a 150 000 km2 area. It is also seen that the August 1913 rainstorm was the most efficient rainstorm over the basin. The rain depth data of severe rainstorms given in this paper can provide a reliable set of information to assess water resource planning on a probability basis. The relationship between the point to areal rainfall and area of the rainstorms from 1- to 3-day durations is also determined.
Southern Ocean Thermocline Ventilation
Authors: Sallée Jean-Baptiste , Speer Kevin , Rintoul Steve , Wijffels S.
Published: October 2009

An approximate mass (volume) budget in the surface layer of the Southern Ocean is used to investigate the intensity and regional variability of the ventilation process, discussed here in terms of subduction and upwelling. Ventilation resulting from Ekman pumping is estimated from satellite winds, the geostrophic mean component is assessed from a climatology strengthened with Argo data, and the eddy-induced advection is included via the parameterization of Gent and McWilliams, together with eddy mixing estimates. All three components contribute significantly to ventilation. Finally, the seasonal cycle of the upper ocean is resolved using Argo data.

The circumpolar-averaged circulation shows an upwelling in the Antarctic Intermediate Water (AAIW) density classes, which is carried north into a zone of dense Subantarctic Mode Water (SAMW) subduction. Although no consistent net production is found in the light SAMW density classes, a large subduction of Subtropical Mode Water (STMW) is observed. The STMW area is fed by convergence of a southward and a northward residual meridional circulation. The eddy-induced contribution is important for the water mass transport in the vicinity of the Antartic Circumpolar Current. It balances the horizontal northward Ekman transport as well as the vertical Ekman pumping.

While the circumpolar-averaged upper cell structure is consistent with the average surface fluxes, it hides strong longitudinal regional variations and does not represent any local regime. Subduction shows strong regional variability with bathymetrically constrained hotspots of large subduction. These hotspots are consistent with the interior potential vorticity structure and circulation in the thermocline. Pools of SAMW and AAIW of different densities are found along the circumpolar belt in association with the regional pattern of subduction and interior circulation.
Vertical Water Velocities from Underwater Gliders
Authors: Merckelbach Lucas , Smeed David , Griffiths Gwyn
Published: October 2009

The underwater glider is set to become an important platform for oceanographers to gather data within oceans. Gliders are usually equipped with a conductivity–temperature–depth (CTD) sensor, but a wide range of other sensors have been fitted to gliders.

In the present work, the authors aim at measuring the vertical water velocity. The vertical water velocity is obtained by subtracting the vertical glider velocity relative to the water from the vertical glider velocity relative to the water surface. The latter is obtained from the pressure sensor. For the former, a quasi-static model of planar glider flight is developed. The model requires three calibration parameters, the (parasite) drag coefficient, glider volume (at atmospheric pressure), and hull compressibility, which are found by minimizing a cost function based on the variance of the calculated vertical water velocity.

Vertical water velocities have been calculated from data gathered in the northwestern Mediterranean during the Gulf of Lions experiment, winter 2008. Although no direct comparison could be made with water velocities from an independent measurement technique, the authors show that, for two different heat loss regimes (≈0 and ≈400 W m−2), the calculated vertical velocity scales are comparable with those expected for internal waves and active open ocean convection, respectively. High noise levels resulting from the pressure sensor require the water velocity time series to be low-pass filtered with a cutoff period of 80 s. The absolute accuracy of the vertical water velocity is estimated at ±4 mm s−1.
The Influence of COX-2 Single Nucleotide Polymorphisms on Abdominal Aortic Aneurysm Development and the Associated Inflammation
Authors: Badger Stephen A. , Soong Chee V. , Young Ian S. , McGinty Ann , Mercer Caroline , Hughes Anneq E.
Published: October 2009

Introduction

Cyclooxygenase (COX)-2 influences cardiovascular disease and serum concentration of high-sensitivity C-reactive protein (hsCRP). The study purpose was to determine the influence of single nucleotide polymorphisms (SNPs) of the COX-2 gene on abdominal aortic aneurysm (AAA) development and serum hsCRP concentrations.

Patients and Methods

Patients with AAA and disease-free controls were recruited. High-sensitivity C-reactive protein was measured by an enzyme-linked immunosorbent assay (ELISA) test. The distributions of COX-2 SNPs were investigated (rs20417 and rs4648307). The influence of the COX-2 SNPs on the hsCRP serum concentration was assessed.

Results

A total of 230 patients with AAA and 279 controls were included. No difference was found in the genotype distribution of the COX-2 SNPs rs20417 ( P = .26) and rs4648307 ( P = .90). They did not influence the hsCRP concentration ( P = .24 and P = .61, respectively). Haplotype analysis of COX-2 SNPs revealed no difference.

Conclusion

These COX-2 SNPs do not play any role in AAA development and do not influence serum hsCRP. These results differentiate AAA development from atherosclerotic diseases.
Acute Limb Ischemia Caused by Femoral Arterial Line Induces Remote Liver Injury in a Rabbit Model of Liver Ischemia/Reperfusion Injury
Authors: Glantzounis Georgios K. , Sheth Hemant , Thompson Cecil , Hafez Tariq S. , Kanoria Sanjeev , Pamecha Viniyendra , Davies Susan , Mikhailidis Dimitri P. , Seifalian Alexander M. , Davidson Brian R.
Published: October 2009

Femoral arterial lines are used for continuous monitoring of arterial blood pressure in experimental studies. However, placement of a catheter in the femoral artery could produce acute limb ischemia with associated systemic effects. The aim of this study was to investigate the effect of femoral arterial line insertion on liver function, in a rabbit liver lobar ischemia-reperfusion (I/R) model. Four groups of animals (n = 6 each) were studied: groups 1 and 2 (sham) underwent laparotomy but no liver ischemia. In groups 3 and 4 (I/R), liver lobar ischemia was induced for 60 minutes followed by 7 hours of reperfusion. In groups 1 and 3, the arterial line was placed in the femoral artery whereas in groups 2 and 4 in the ear artery. Liver function was assessed by serum alanine aminotransferase (ALT) activity, bile flow, plasma lactate levels, and histology. Results are expressed as mean ± SEM. Alanine aminotransferase activity and lactate levels were significantly higher in the I/R femoral line group compared with the I/R ear line group at 7 hours postreperfusion. Bile production was significantly lower (75 ± 9.6 vs 112 ± 10 μL/min per 100 g liver weight). Histopathology showed more extensive hepatocellular necrosis and neutrophil accumulation in the I/R femoral line group compared with I/R ear line group. The sham femoral group showed liver injury, which was more marked than the ear line group (all P < .05). In conclusion, femoral artery cannulation induces remote liver injury. The use of femoral arterial lines should be avoided in experimental studies concerning liver function.
Pen Pals Without Borders: A Cultural Exchange of Teaching and Learning
Authors: Thompson McMillon Gwendolyn Michele
Published: October 2009

When teachers and students are from different cultures, dissonance can occur in classrooms, which can be debilitating for effective literacy teaching and learning. Researchers have conducted studies in urban schools for many years, but the problem of cultural dissonance continues to plague many classrooms. It is imperative that teacher education programs develop creative, effective ways to prepare the teaching population to meet the needs of a diverse student population. This article reports the findings of a pen pal cultural exchange project between 40 predominantly White, female, preservice teachers in an elementary reading methods course, and 26 predominantly Black, fourth graders in an urban elementary school.The study analyzes 336 letters (154 children letters and 182 adult letters) to identity overarching themes. The content of the letters are analyzed using discourse analysis. The three most frequently found themes are shared experiences, overcoming adversities, and cultural practices and experiences. This study provides specific, practical methods for teacher educators to utilize in their courses and to help teachers and teacher candidates acquire important cultural knowledge and develop skills that prepare them to effectively teach the diverse student population in the United States. In particular, it provides a framework and specific ways to implement a pen pal cultural exchange project between preservice teachers and elementary students—students from two different worlds who became “border-crossers”.
The Influence of Salary in Attracting and Retaining School Leaders
Authors: Pijanowski John C. , Brady Kevin P.
Published: October 2009

This article examines the salary trajectory of teachers as they move up the career ladder into leadership positions. The issue of compensation is set in the context of a principal shortage that has been widely reported and discussed in the literature. Urban schools are shown to experience the principal shortage differently from rural schools. District size and school type show significant differences in the additional compensation offered for moving from teaching to various leadership positions. The influence of salary is discussed in concert with the changing role of the principalship and candidate’s concerns about increasingly less desirable working conditions for school leaders.
Harnessing the Power of Education Research Databases With the Pearl-Harvesting Methodological Framework for Information Retrieval
Authors: Sandieson Robert W. , Kirkpatrick Lori C. , Sandieson Rachel M. , Zimmerman Walter
Published: October 2009

Digital technologies enable the storage of vast amounts of information, accessible with remarkable ease. However, along with this facility comes the challenge to find pertinent information from the volumes of nonrelevant information. The present article describes the pearl-harvesting methodological framework for information retrieval. Pearl harvesting relies on the sampling of articles from a body of literature to extract the relevant search keywords. The general steps for using this method were applied to finding the essential list of search keywords for the topic of developmental disabilities. The success with the present investigation suggests that pearl harvesting might be used as a framework to develop keyword search lists in other areas, thereby providing a general methodology to help manage comprehensive literature reviews.