bluuebunny/crossref_metadata_2025 huggingface dataset:
Chronic treatment with vitamin D lowers arterial blood pressure and reduces endothelium-dependent contractions in the aorta of the spontaneously hypertensive rat
Authors: Wong Michael S. K. , Delansorne R. , Man Ricky Y. K. , Svenningsen P. , Vanhoutte Paul M.
Published: August 2010

Vitamin D has cardiovascular protective effects besides regulating calcium homeostasis. To examine the chronic in vivo effect of a physiological dose of 1,25-dihydroxyvitamin D3on the occurrence of endothelium-dependent contractions, spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were treated with the vitamin D derivative for 6 wk. The serum 1,25-dihydroxyvitamin D3level of both treated WKY and SHR was significantly higher than in untreated rats while the mean arterial blood pressure of the treated SHR was significantly lower than that of control SHR. Aortic rings with or without endothelium were studied in conventional organ chambers for isometric force measurement. Confocal microscopy was used to measure the cytosolic free calcium concentration (with the fluorescent dye fluo 4) and reactive oxygen species (ROS; with dichlorodihydrofluorescein diacetate). Reverse transcription PCR and Western blotting were used to determine the mRNA and protein expression level of cyclooxygenase-1 (COX-1), prostacyclin synthase, and thromboxane synthase. The endothelium-dependent concentration-contraction curves to both acetylcholine- and A-23187-induced contractions were shifted to the right in aortas from treated SHR but not from treated WKY. The chronic treatment normalized the relaxations of contracted preparations to acetylcholine. There were no significant differences in the increases in cytosolic free calcium concentration evoked by acetylcholine and A-23187 between control and treated groups. The endothelial ROS level was higher in SHR than WKY aortas and reduced by the chronic treatment. The gene and protein expression studies indicated that the overexpression of COX-1 observed in SHR aorta was reduced by the chronic treatment. These results demonstrate that chronic treatment with 1,25-dihydroxyvitamin D3modulates vascular tone and this modulation is accompanied by a lowered blood pressure, reduced expression of COX-1 mRNA and protein, and reduced ROS level in SHR. The reduction in endothelium-dependent contractions does not involve the surge in endothelial cytosolic calcium concentration that initiates the contractions.
Differential induction of CD38 expression by TNF-α in asthmatic airway smooth muscle cells
Authors: Jude Joseph A. , Solway Julian , Panettieri Reynold A. , Walseth Timothy F. , Kannan Mathur S.
Published: August 2010

The ADP-ribosyl cyclase activity of CD38, a membrane protein expressed in human airway smooth muscle (ASM) cells, generates cyclic ADP-ribose (cADPR), a Ca2+-mobilizing agent. cADPR-mediated Ca2+responses to agonists are augmented in human ASM cells by TNF-α. CD38-deficient mice fail to develop airway hyperresponsiveness following intranasal TNF-α or IL-13 challenge, suggesting a role in asthma. The role of CD38 in human asthma remains unknown. We hypothesized that CD38 expression will be elevated in ASM cells from asthmatic donors (ASMA cells). CD38 mRNA and ADP-ribosyl cyclase activity were measured in cells maintained in growth-arrested conditions and exposed to vehicle or TNF-α (10–40 ng/ml). TNF-α-induced induction of CD38 expression was greater in ASMA than in ASM cells from nonasthmatic donors (ASMNA). In four of the six donors, basal and TNF-α-induced ERK and p38 MAPK activation were higher in ASMA than ASMNA cells. JNK MAPK activation was lower in ASMA than ASMNA cells. Nuclear NF-κB (p50 subunit) and phosphorylated c-Jun were comparable in cells from both groups, although nuclear c-Fos (part of the AP-1 complex) levels were lower in ASMA than ASMNA cells. NF-κB or AP-1 binding to their consensus sequences was comparable in ASMNA and ASMA cells, as are the decay kinetics of CD38 mRNA. The findings suggest that the differential induction of CD38 by TNF-α in ASMA cells is due to increased transcriptional regulation involving ERK and p38 MAPK activation and is independent of changes in NF-κB or AP-1 activation. The findings suggest a potential role for CD38 in the pathophysiology of asthma.
Glucocorticoids potentiate IL-6-induced SP-B expression in H441 cells by enhancing the JAK-STAT signaling pathway
Authors: Ladenburger Andreas , Seehase Matthias , Kramer Boris W. , Thomas Wolfgang , Wirbelauer Johannes , Speer Christian P. , Kunzmann Steffen
Published: August 2010

The respiratory distress syndrome (RDS) contributes to perinatal morbidity and mortality associated with preterm birth. Surfactant protein B (SP-B) is decreased in RDS. Both maternal antenatal steroid administration and chorioamnionitis reduce the incidence and severity of RDS. An important mediator in chorioamnionitis is IL-6 using the JAK-STAT signaling pathway for signal transduction. We hypothesized that the steroids, betamethasone (BTM) and dexamethasone (DXM), and IL-6 had synergistic effects on SP-B gene expression and STAT3 phosphorylation in H441 cells. DXM and BTM increased SP-B mRNA levels by 16.5 (13.3)-fold and IL-6 alone by 2.3-fold. After 48-h exposure of cells to DXM or BTM, IL-6 caused a significantly greater increase in SP-B mRNA levels (28.1-fold) than IL-6 or glucocorticoids alone. Whereas IL-6 stimulated tyrosine phosphorylation of STAT3 in a time- and dose-dependent way, DXM and BTM had no effect on STAT3 phosphorylation. Both DXM and BTM could potentiate IL-6-induced phosphorylation of STAT3. The synergism of glucocorticoids and IL-6 on SP-B gene expression and the effect of glucocorticoids on IL-6-induced STAT3 phosphorylation could be blocked by a JAK inhibitor. Expression level analysis showed that glucocorticoids increased the expression of the IL-6-binding α-subunit receptor (IL-6R) on mRNA and protein level. Our findings could represent an example of a pulmonary regulation system in which one role of glucocorticoids is to increase the effect of a cytokine by upregulation of its receptor. The described in vitro interaction of IL-6 and glucocorticoids could help explain the clinical observation that prenatal inflammation in preterm babies with antenatal steroid administration can attenuate severity of RDS.
Rapid in vivo whole body composition of rats using cone beam μCT
Authors: Granton Patrick V. , Norley Chris J. D. , Umoh Joseph , Turley Eva A. , Frier Bruce C. , Noble Earl G. , Holdsworth David W.
Published: August 2010

Precise, noninvasive analysis and quantification of in vivo body composition is essential for research involving longitudinal, small-animal disease models. We investigated the feasibility and precision of a rapid, flat-panel μCT scanner to report whole body adipose tissue volume (ATV), lean tissue volume (LTV), skeletal tissue volume (STV), and bone mineral content (BMC) in 25 postmortem female and 52 live male Sprague-Dawley rats. μCT images, acquired in three 90-mm segments and reconstructed with 308 μm of isotropic voxel spacing, formed contiguous image volumes of each entire rat specimen. Three signal-intensity thresholds (determined to be −186, 5, and 155 HU) were used to classify each voxel as adipose, lean, or skeletal tissue, respectively. Tissue masses from the volume fractions of ATV, LTV, and STV were calculated from assumed tissue densities of 0.95, 1.05, and 1.92 g/cm−3, respectively. A CT-derived total mass was calculated for each rat and compared with the gravimetrically measured mass, which differed on average for the postmortem female and the live male group by 2.5 and 1.1%, respectively. To evaluate the accuracy of the CT-derived body composition technique, following the live male study excised muscle tissue in the lower right leg of all rats in group B were compared with the image-derived LT measurement of the same regional compartment and found to differ on average by 2.2%. Through repeated CT measurements of postmortem specimens, the whole body ATV, LTV, STV, and BMC measurement analysis gave a precision value of ±0.6, 1.9, 1.7, and 0.5% of the average value, respectively.
Changes in Plasma Testosterone Levels and Brain AVT Cell Number during the Breeding Season in the Green Treefrog
Authors: O’Bryant Erin L. , Wilczynski Walter
Published: August 2010

We exposed groups of adult male green treefrogs, Hyla cinerea, to acoustic stimuli (natural chorus or random tones) for seven consecutive nights at three time points during their natural breeding season (May, July, and September) and assessed seasonal changes in plasma androgen levels and number of arginine vasotocin (AVT) immunoreactive cells in the brain over this time period. We also tested whether social cues altered either androgens or AVT-ir cell number or size at each time point. Finally, we analyzed how these factors related to calling behavior. Data were collected over two breeding seasons. Call rate (calls/h) was assessed during the stimulus time (i.e. ‘evoked calling’) and during the remainder of the day (‘spontaneous calling’). Plasma hormone levels were measured at the end of the acoustic treatment when brains were collected for immunocytochemistry. Circulating androgen levels declined over the breeding season. Males exposed to chorus sounds, however, had higher androgen levels than males exposed to tones. AVT-ir cell number increased across the breeding season in the nucleus accumbens but not the amygdala, anterior preoptic area, or magnocellular preoptic area, and soma size decreased in the nucleus accumbens as cell number increased. Social stimulation had no significant influence on either AVT-ir cell measure. Evoked call rate was higher in males exposed to natural chorus sounds compared to those exposed to random tones, but did not change during the season. In contrast, spontaneous call rate was higher at the beginning of the breeding season compared to the end, and unlike evoked calling was correlated with circulating androgen levels across all treatments and time points. AVT-ir soma size was positively correlated with both evoked and spontaneous calling. These results suggest that social exposure can prolong the elevation of gonadal hormones in the bloodstream, thus mitigating or slowing the seasonal decline of such hormones. In contrast, social exposure does not affect the seasonal pattern of AVT-ir cell number or soma size. The reciprocal relationship between social cues and hormones and the subsequent effect on behavior may provide hidden benefits to animals engaging in social interactions. However, unlike steroid hormone levels, the seasonal change in AVT-ir cell number and size is not counteracted by social stimulation.
Dual Arterial Cannulation for Aortic Surgical Procedures in Adult Sheep
Authors: Kopcak, Jr. M.W. , Barka N. , Rakow N. , Leet C. , Shecterle L.M. , St. Cyr J.A.
Published: August 2010

Background/Aims: Preclinical site-specific placement of valvular prostheses is highly recommended to fully appreciate hemodynamics. An ovine model is commonly used for preclinical prosthetic mitral valve evaluation; however, the ideal animal model for prosthetic aortic valve evaluation has yet to be determined. Past studies have utilized adult sheep for prosthetic aortic valve replacement; however, an anatomically short length of the ascending aorta can present a surgical challenge during implantation. Due to this anatomically short length of the ascending aorta, we designed an arterial cannulation technique for cardiopulmonary bypass (CPB) to provide a more ideal operative setting. Methods: Dual arterial cannulation for CPB was used in adult Polypay sheep (n = 15) subjected to an aortic root/valve surgical procedure. Results: The arterial cannulation technique described in this paper was successful in performing aortic root/valve surgical procedures in adult sheep. All animals survived the operative procedure without complications. Postoperatively, all animals were alert, neurologically intact and assumed normal daily functions following extubation, which continued throughout their survival. Conclusions: The use of this arterial cannulation technique was safe, provided better visualization of the aortic root/valve area, less difficulty in performing the aortic root/valve surgical procedure, and less observed tissue tension while closing the aortotomy.
Comparative Morphology of the Mechanosensory Lateral Line System in a Clade of New Zealand Triplefin Fishes
Authors: Wellenreuther Maren , Brock Michelle , Montgomery John , Clements Kendall D.
Published: August 2010

The mechanoreceptive lateral line system in fishes detects hydrodynamic stimuli and plays a critical role in many fundamental behaviours, including orientation to water currents and the detection of stationary objects, prey and predators. Interspecific variation in lateral line structure may result from a process of functional adaptation, with the background level of hydrodynamic activity proposed as an important selective pressure. Here we use the eight species of the ecologically diverse New Zealand marine triplefin fish of the genus Forsterygion and one species from the sister genus Notoclinops to investigate interspecific differences in lateral line morphology and to assess the relationship between lateral line characteristics and exposure to wave energy (fetch/depth ratio). Overall, the results show that lateral line traits are divergent between species, and these differences could in part be related to the wave exposure of the habitats that the species occupy. Specifically, numbers of canal neuromasts differed significantly between species, and most canal groupings increased in neuromast number with fetch/depth ratio, while the number and area of some superficial neuromast groupings decreased significantly with exposure. Distribution of superficial neuromasts along the trunk in the semi-pelagic and paedomorphic species F. maryannae differed from the other, demersal species, which may be associated with the unique lifestyle of this species and/or developmental processes. Canal architecture also differed considerably between species, but displayed no relationship with fetch/depth ratio. The results from this study indicate that some interspecific differences in lateral line organs may be a by-product of selection for habitat divergence. Future work should explore additional causal factors that might have influenced the evolution of lateral morphology in these species, including phylogenetic and allometric effects.
In vitro Epstein-Barr Virus Infection Model of Rabbit Lymphocytes from Peripheral Blood or Spleen
Authors: Kanai Kyosuke , Kato Kaoru , Sano Hitoshi , Nagata Keiko , Okuno Keisuke , Kuwamoto Satoshi , Higaki Hiromi , Sugihara Hirotsugu , Kato Masako , Murakami Ichiro , Hayashi Kazuhiko
Published: August 2010

Most humans become lifelong carriers of Epstein-Barr virus (EBV) by adulthood. Primary EBV infection in adolescents causes infectious mononucleosis. EBV infection is associated with various diseases, neoplasms and hematological disorders. Recently, we reported that EBV can infect rabbits by intravenous, intranasal and/or peroral inoculation, which caused primary EBV infection in rabbits with heterogeneous host reactions. Some rabbits showed chronic and lifelong EBV infection with hemophagocytosis. In this study, to reveal detailed mechanisms in rabbit EBV infection, an in vitro investigation was performed. We elucidated that: (1) EBV can infect rabbit peripheral blood mononuclear cells and splenic lymphocytes in vitro, because EBV gene expressions were confirmed. (2) It is highly likely that the B cell is the main target cell of rabbit EBV infection and is immortalized similar to humans. (3) CD8+ T cells increased in the rabbit in vivo model after EBV inoculation, whereas an increase of B cells occurred after their transient decrease. These data suggest that EBV-infected B cells were proliferated, while CD8+ T cells increased to recognize and kill them. This system may explain the paths of rabbit EBV infection and host reaction, simulating human EBV infection. In vitro studies will be helpful to reveal the pathogenesis of rabbit EBV infection and EBV-associated diseases.
Structure of Vibriophage D10 Tail Sheath Revealed by Electron Microscopy and Computational Image Processing
Authors: Sen Anindito , Ghosh Amar N.
Published: August 2010

Vibriophage D10, a member of the Vibrio cholerae O-1El-Tor phage typing scheme, is used to detect the spread of the cholera epidemic and belongs to the Myoviridae family. The outer sheath of the tail of vibriophage is highly contractile in nature. We have used electron microscopy and computational image-processing techniques to determine the structure of this contractile tail sheath. The three-dimensional density map of the tail sheath reveals the presence of ∼35 Å long and ∼25 Å wide protrusions, extending out of the tail structure. The electron micrographs revealed that the tail sheaths of a considerable number of D10 phage particles undergo axial compression up to 51% at almost neutral pH (7.2) and at room temperature (20°). We find that the genome of the phage particles is ejected out when the tail sheath of the phage particles are deliberately made to contract by subjecting them to a surrounding environment of pH 10.5. We infer that the contraction of the tail sheath is responsible for the loss of the phage genome even at neutral pH and room temperature. This may be a plausible reason for the unusual behavior of rapid decline of the phage within a span of 48–72 h of its preparation.
Interleukin-18 as a Predictor of Future Events in Patients With Acute Coronary Syndromes
Authors: Hartford Marianne , Wiklund Olov , Hultén Lillemor Mattsson , Persson Anita , Karlsson Thomas , Herlitz Johan , Hulthe Johannes , Caidahl Kenneth
Published: August 2010

Objective—

The aim of this study was to assess the short- and long-term prognostic significance of interleukin-18 (IL-18) levels in patients with acute coronary syndromes (ACS).

Methods and Results—

In patients hospitalized with ACS (median age, 66 years; 30% females), we evaluated associations of serum IL-18 levels from day 1 (n=1261) with the short- (<3 months) and long-term (median, 7.6 years) risk of death, development of congestive heart failure (CHF), and myocardial infarction (MI). IL-18 was not significantly associated with short-term mortality. In the long term, IL-18 levels were significantly related to all-cause mortality, even after adjustment for clinical confounders (hazard ratio [HR], 1.19; 95% confidence interval, 1.07 to 1.33;
P
=0.002). Long-term, cardiovascular mortality was univariately related to IL-18, and the adjusted relation between noncardiovascular mortality and IL-18 was highly significant (HR, 1.36; 95% confidence interval, 1.11 to 1.67;
P
=0.003). IL-18 independently predicted CHF, MI, and cardiovascular death/CHF/MI in both the short and long term. Measurements from day 1 of ACS and 3 months after ACS had a similar power to predict late outcome.

Conclusion—

The addition of the measurement of IL-18 to clinical variables improved the prediction of risk of all-cause and noncardiovascular mortality. The association between IL-18 and noncardiovascular mortality is intriguing and warrants further study.
Endogenous KLF4 Expression in Human Fetal Endothelial Cells Allows for Reprogramming to Pluripotency With Just OCT3/4 and SOX2—Brief Report
Authors: Ho Pai-Jiun , Yen Men-Luh , Lin Jhong-De , Chen Lan-Sun , Hu Hsin-I , Yeh Chun-Kai , Peng Chiu-Ying , Lin Chen-Yu , Yet Shaw-Fang , Yen B. Linju
Published: August 2010

Objective—

The introduction of 4 transcription factors—c-MYC, OCT3/4, SOX2, and KLF4—can reprogram somatic cells back to pluripotency. However, some of the factors used are oncogenic, making therapeutic application unfeasible. Although the use of adult stem cells expressing high endogenous levels of some of these factors allows for reprogramming with fewer exogenous genes, such cells are rare and may have accumulated genetic mutations. Our goal was to reprogram human somatic cells without oncogenic factors. We found that high endogenous expression of
KLF4
in human umbilical vein endothelial cells (HUVECs) allows for generation of induced pluripotent stem cells (iPSCs) with just 2 nononcogenic factors,
OCT3/4
and
SOX2
.

Methods and Results—

HUVECs were infected with lentivirus containing OCT4 and SOX2 for generation of iPSCs. These 2-factor HUVEC iPSCs were morphologically similar to embryonic stem cells, express endogenous pluripotency markers postreprogramming, and can differentiate toward lineages of all 3 germ layers both in vitro and in vivo.

Conclusion—

iPSCs can be generated from HUVECs with only 2 nononcogenic factors. The use of fetal cells for reprogramming without oncogenic factors may provide an efficient in vitro model for human iPSC research, as well as a novel source for possible therapeutic use.
Safety and Efficacy of Pulmonary Vein Antral Isolation in Patients With Obstructive Sleep Apnea
Authors: Patel Dimpi , Mohanty Prasant , Di Biase Luigi , Shaheen Mazen , Lewis William R. , Quan Kara , Cummings Jennifer E. , Wang Paul , Al-Ahmad Amin , Venkatraman Preeti , Nashawati Eyad , Lakkireddy Dhanunjaya , Schweikert Robert , Horton Rodney , Sanchez Javier , Gallinghouse Joseph , Hao Steven , Beheiry Salwa , Cardinal Deb S. , Zagrodzky Jason , Canby Robert , Bailey Shane , Burkhardt J. David , Natale Andrea
Published: August 2010

Background—

Obstructive sleep apnea (OSA) may be associated with pulmonary vein antrum isolation (PVAI) failure. The aim of the present study was to investigate if treatment with continuous positive airway pressure (CPAP) improved PVAI success rates.

Methods and Results—

From January 2004 to December 2007, 3000 consecutive patients underwent PVAI. Patients were screened for OSA and CPAP use. Six hundred forty (21.3%) patients had OSA. Patients with OSA had more procedural failures (
P
=0.024) and hematomas (
P
<0.001). Eight percent of the non-OSA paroxysmal atrial fibrillation patients had nonpulmonary vein antrum triggers (non-PV triggers) and posterior wall firing versus 20% of the OSA group (
P
<0.001). Nineteen percent of the non-OSA nonparoxysmal atrial fibrillation population had non-PV triggers versus 31% in the OSA group (
P
=0.001). At the end of the follow-up period (32±14 months), 79% of the non-CPAP and 68% of the CPAP group were free of atrial fibrillation (
P
=0.003). Not using CPAP in addition to having non-PV triggers strongly predicted procedural failure (hazard ratio, 8.81;
P
<0.001).

Conclusions—

OSA was an independent predictor for PVAI failure. Treatment with CPAP improved PVAI success rates. Patients not treated with CPAP in addition to having higher prevalence of non-PV triggers were 8 times more likely to fail the procedure.
YHWH’s Call for Israel’s ‘Return’: Command, Invitation, or Threat
Authors: Jacobs Mignon R.
Published: August 2010

The call for Israel’s return to YHWH resounds in the prophetic text and utilizes various images to illustrate Israel’s and YHWH’s behaviors. These images depict the strained relationship between YHWH and Israel and the persistence of the Deity in maintaining the relationship. This study focuses on Hosea 11 and Amos 4 as examples of the call and distinct perspectives of the YHWH-Israel behavioral and relational dynamics. It looks at the place of the past, present, and future in the formulation of the call to return and offers conclusions about the implications of the analysis on the understanding of the YHWH-Israel relationship.
God as F(r)iend? Reading Luke 11:5-13 & 18:1-8 with a Hermeneutic of Suffering
Authors: Metzger James A.
Published: August 2010

Employing an optic grounded in suffering and foregrounding intertexts in which God is portrayed unfavorably, it is argued that in Luke 11:5-13 and 18:1-8 Jesus acknowledges a negative experience and conception of the deity among some of early Roman Palestine’s “poor ... captives ... blind ... [and] oppressed” (4:18-19). Jesus does not ask them to suppress their impressions of God or to align them with more traditional representations; rather, they are encouraged to remain in conversation with the deity and not to become discouraged or be afraid, even when their speech pushes beyond socially acceptable limits and becomes accusatory, contemptuous, blasphemous, or outright hostile. Indeed, Jesus recommends impudence and audacious tenacity before God, confident that such conduct will receive a hearing and a response.
GRAPHICAL INTEGRATIONS OF A TWO-LEVEL MODEL
Authors: Estoque M. A.
Published: August 2010

A prediction model representing a slight modification of a previous model (Estoque, 1956a) is presented. The prediction equations were integrated graphically to produce 24-hour 1000- and 500-millibar forecasts for the month of January 1953. The results indicate that the method may be of considerable value in routine forecasting, particularly in regions where orographic influences are no great concern.
CLOUD PHOTOGRAMMETRY WITH GROUND-LOCATED K-17 AERIAL CAMERAS
Authors: Kassander A. Richard , Sims Lee L.
Published: August 2010

A technique is presented in which a pair of ground-located K-17 aerial cameras is used on a 1.30-milebaseline to determine cloud ranges to 1-mi accuracy at 40 mi, and cloud-height measurements to within 500 feet at this range. Details of the power supply, vacuum supply, and camera-synchronization requirements are discussed, as well as methods used in analysis. In particular, a detailed discussion is given of the theoretical and practical errors encountered in such a photogrammetric technique.
ON THE INTEGRATION OF THE HEAT-CONDUCTION EQUATION WITH PERIODIC VARIATION OF TEMPERATURE
Authors: de Vries D. A.
Published: August 2010

An integration of the Fourier equation of heat conduction in a semi-infinite medium (air) is presented for the case where the thermal (or eddy) diffusivity varies with height, assuming a harmonic variation of temperature with time. Special attention is paid to the case where the medium consists of an arbitrary number of layers in each of which the diffusivity is represented by a different function of height.

Application of these methods resolves some of the difficulties encountered in explaining the observed variation of amplitude and phase of the temperature wave with height. It is concluded that —although theoretically possible —it is not feasible in practice to evaluate the diffusivity from an analysis of observations of this type, and that some results of previous attempts to do so are largely in error.

Relations between the waves of temperature and heat flux near the surface are briefly discussed. It is shown that for the diurnal waves these depend, inter alia, on the diffusivity values up to a height of the order of 1000 meters.
SPECTRUM MODIFICATION DUE TO THE USE OF FINITE DIFFERENCES
Authors: Ogura Y.
Published: August 2010

The modification of the vorticity spectrum associated with the use of finite differences instead of derivatives is considered for an isotropic turbulence field. The results permit a rough estimate of the dependence of the magnitude of vorticity on the grid spacing.
Reply
Authors: Gunn Ross
Published: August 2010

No Abstract Available.
ADDITIONAL REMARKS
Authors: Appleman H.
Published: August 2010

No Abstract Available.
COMMENTS ON "A STUDY OF A CHARACTERISTIC TYPE OF UPPER-LEVEL FRONTOGENESIS"
Authors: Boville B. W. , Creswick W. S.
Published: August 2010

No Abstract Available.
CORRECTION TO "A THREE-PARAMETER BAROCLINIC NUMERICAL-PREDICTION MODEL"
Authors: Berkofsky Louis
Published: August 2010

Correction to Volume 13, Issue 1, Article 102.
Improvements to a Commonly Used Cloud Microphysical Bulk Parameterization
Authors: Potter Brian E.
Published: August 2010

No abstract available.
Reply
Authors: Rodgers Edward , Stout John , Steranka Joseph , Chang Simon
Published: August 2010

No abstract available.
Accuracy of Satellite Land Surface Reflectance Determination
Authors: Arino O. , Dedieu G. , Deschamps P. Y.
Published: August 2010

An accuracy budget of the surface reflectance determination from Meteosat geostationary satellite data is performed. Error analysis allows identification of three main problems: calibration uncertainty of the Meteosat instrument, atmospheric corrections, and surface effects (spectral and directional). Calibration accuracy is 10%, leading to a 10% relative uncertainty on reflectance. Spectral effects of the surface lead to a maximum bias of 0.01 for a vegetated surface as sensed by Meteosat, while directional effects can lead to a bias of 0.035 between two measurements taken at two different sun zenith and azimuth angles at the same view angle over savannas. The maximum error due to the atmosphere is estimated to be of the order of 0.03 in reflectance for a surface reflectance of 0.40 and 0.01 for, a surface reflectance of 0.10. Validation with in situ measurement is within the expected error over savanna. But the difference is still high over the southwest France site of HAPEX-MOBILHY, certainly due to the joint spectral and directional errors. Comparisons with surface albedo maps from literature show the same spatial and spatial evolutions with a better spatial and temporal determination in our results.
Comparison of Ice-Phase Microphysical Parameterization Schemes Using Numerical Simulations of Tropical Convection
Authors: McCumber Michale , Tao Wei-Kuo , Simpson Joanne , Penc Richard , Soong Su-Tzai
Published: August 2010

A numerical cloud model is used to evaluate the performance of several ice parameterizations. Results from simulations using these schemes are contrasted with each other, with an ice-free control simulation, and with observations to determine to what extent ice physics affect the realism of these results. Two different types of tropical convection are simulated. Tropical squall-type systems are simulated in two dimensions so that a large domain can be used to incorporate a complete anvil. Nonsquall-type convective lines are simulated in three dimensions owing to their smaller horizontal scale.

The inclusion of ice processes enhances the agreement of the simulated convection with some features of observed convection, including the proportion of surface rainfall in the anvil region, and the intensity and structure of the radar brightband near the melting level in the anvil. In the context of our experimental design, the use of three ice classes produces better results than two ice classes or ice-free conditions, and for the tropical cumuli, the optimal mix of the bulk ice hydrometeors is cloud ice-snow-graupel. We infer from our modeling results that application of bulk ice microphysics in cloud models might be case specific, which is a significant limitation. This can have serious ramifications for microwave interpretation of cloud microphysical properties. Generalization of ice processes may require a larger number of ice categories than we have evaluated and/or the prediction of hydrometeor concentrations or particle-size spectra.
JANUARY 1995 NOTES AND CORRESPONDENCE
Authors: Perry Steven G.
Published: August 2010

No abstract available.
Topographic and Atmospheric Influences on Precipitation Variability over a Mountainous Watershed
Authors: Johnson Gregory L. , Hanson Clayton L.
Published: August 2010

Using rotated principal component analysis (PCA), unique, orthogonal spatial patterns of daily and monthlyprecipitation on a well-instrumented, mountainous watershed in Idaho are examined for their relationship totopography, geographic location, and atmospheric variability. Precipitation pattern and homogeneous precipitationregion differences between daily and monthly timescales and between winter and summer Seasons were identifiedusing the rotated PCA procedure. In general, monthly data produced regional boundaries more closely alignedwith topography, reflecting the integration of many storm events on monthly timescales. Spatial fields, derivedfrom mapping rotated component loadings at 46 precipitation stations on a 234-kmz watershed, were found tobe highly correlated with topography and geographic location. The eight-year time series of the components forspecific watershed regions were found to be moderately related to linear combinations of meteorological variablesderived from a single radiosonde station approximately 50 km from the waterhed. This would indicate thepotential usefulness of data from a single location, such as a general circulation model grid point, to provideclues about spatial pattern changes and regional precipitation fluctuations even on a small watershed, if sufficientinformation about local climate (i.e., topographic influences) is first established.
Rain-Rate Estimation in the Presence of Hail Using S-Band Specific Differential Phase and Other Radar Parameters
Authors: Aydin K. , Bringi V. N. , Liu L.
Published: August 2010

Multiparameter radar measurements were made during a heavy rainfall event accompanied by hail in Colorado. Rainfall rates R and accumulation Σ for this event were estimated using S-band specific differential phase KDP, reflectivity factor ZH, and X-band specific attenuation AH3. These estimates were compared with measurements from a ground-based rain gauge. Both R–KDP and R–AH3 relations were in good agreement with the rain gauge data, that is, less than 10% difference in the rainfall accumulations. The R–Z relation produced similar results only when ZH was truncated at 55 dBZ. This study demonstrates the potential of KDP for estimating rainfall rates in severe storms that may have rain-hail mixtures.
Removal of the Solar Component in AVHRR 3.7-µm Radiances for the Retrieval of Cirrus Cloud Parameters
Authors: Rao N. X. , Ou S. C. , Liou K. N.
Published: August 2010

A numerical scheme has been developed to remove the solar component in the Advanced Very High Resolution Radiometer (AVHRR) 3.7-µm channel for the retrieval of cirrus parameters during daytime. This method uses a number of prescribed threshold values for AVHRR channels 1 (0.63 µm), 2 (0.8 µm), 3 (3.7 µm), 4 (10.9 µm), and 5 (12 µm) to separate clear and cloudy pixels. A look-up table relating channels 1 and 3 solar reflectances is subsequently constructed based on the prescribed mean effective ice crystal sizes and satellite geometric parameters. An adding–doubling radiative transfer program has been used to generate numerical values in the construction of the look-up table. Removal of the channel 3 solar component is accomplished by using the look-up table and the measured channel 1 reflectance. The cloud retrieval scheme described in Ou et al. has been modified in connection with the removal program. The authors have applied the removal–retrieval scheme to the AVHRR global area coverage daytime data, collected during the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment cirrus intensive field observation (FIRE IFO) at 2100 UTC 28 October 1986 over the Wisconsin area. Distributions of the retrieved cloud heights and optical depths are comparable to those determined from Geostationary Operational Environmental Satellite visible and IR channels data reported by Minnis et al. Morwver, verifications of the retrieved cirrus temperature and height against lidar data have been carried out using results reported from three FIRE IFO nations. The retrieved cloud heights are within 0.5 km of the measured lidar values.
Quantitative Estimates of Cloudiness over the Gulf Stream Locale Using GOES VAS Observations
Authors: Alliss Randall J. , Raman Sethu
Published: August 2010

Fields of cloudiness derived from the Geostationary Operational Environmental Satellite VISSR (Visible–Infrared Spin Scan Radiometer) Atmospheric Sounder are analyzed over the Gulf Stream locale (GSL) to investigate seasonal and geographical variations. The GSL in this study is defined as the region bounded from 31° to 38°N and 82° to 66°W. This region covers an area that includes the United States mid-Atlantic coast states, the Gulf Stream, and portions of the Sargasso Sea. Clouds over the GSL are found approximately three-quarters of the time between 1985 and 1993. However, large seasonal variations in the frequency of cloudiness exist. These seasonal variations show a distinct relationship to gradients in sea surface temperature (SST). For example, during winter when large SST gradients are present, large gradients in cloudiness are found. Clouds are observed least often during summer over the ocean portion of the GSL. This minimum coincides with an increase in atmospheric stability due to large-scale subsidence. Cloudiness is also found over the GSL in response to mesoscale convergence areas induced by sea surface temperature gradients. Geographical variations in cloudiness are found to be related to the meteorology of the region. During periods of cold-air advection, which are found most frequently in winter, clouds are found less often between the coastline and the core of the Gulf Stream and more often over the Sargasso Sea. During cyclogenesis, large cloud shields often develop and cover the entire domain.

Satellite estimates of cloudiness are found to be least reliable over land at night during the cold months. In these situations, the cloud retrieval algorithm often mistakes clear sky for low clouds. Satellite-derived cloudiness over land is compared with daytime surface observations of cloudiness. Results indicate that retrieved cloudiness agrees well with surface observations. Relative humidity fields taken from global analyses are compared with satellite cloud heights at three levels in the atmosphere. Cloudiness observed at these levels is found at relative humidities in the 75%–100% range but is also observed at humidities as low as 26%.
The Influence of Forests on Atmospheric Heating during the Snowmelt Season
Authors: Yamazaki Takeshi
Published: August 2010

Atmospheric heating during the snowmelt season has been studied by means of data analysis and numerical model experiments. As a result of the data analysis, it was shown that in some examples the daytime air temperature rose above 0°C, even if the ground surface was covered by snow. Moreover, it was found that the number of days when the daytime air temperature rose above 0°C was large when the duration of sunshine increased. However, the increase was not related to the wind speed. Therefore, the air temperature over snow cover increases during the daytime if the sunshine is strong even under calm conditions (weak advection). On the other hand, the following result was obtained with the use of a local circulation model combined with a canopy heat balance model. The atmosphere was heated over the plains if forested areas existed around the plains, even if the plains surfaces were covered by snow without forests. An upward sensible heat flux was supplied from the forest canopy, resulting in atmospheric heating. It was concluded that the existence of forests was one of the main causes of atmospheric heating during the snowmelt season.
Trajectories for Saharan Dust Transported to Barbados Using Stokes's Law to Describe Gravitational Settling
Authors: Ellis W. G. , Merrill J. T.
Published: August 2010

Atmospheric chemistry programs often make use of retrospective back trajectories to determine the source regions of substances sampled at a particular site. Isentropic trajectories, which depict motion on hypothetical surfaces of constant potential temperature, have been used as part of the Atmosphere/Ocean Chemistry Experiment to understand the sources of aerosols and gases sampled over the North Atlantic Ocean. However, isentropic trajectories typically do not adequately describe the transport of mineral aerosol, for example, from the Sahara Desert to Barbados. Boundary layer trajectories indicated that northern Africa was the source region for 12% of the samples with significant aluminum (Al) concentrations (> 1.0 µg m−3). Upper-level isentropic trajectories (310 and 315 K) indicated transport from northern Africa for approximately half of the samples with Al concentrations greater than 1.0 µg m−3. However, at the location of the sampling site, the upper-level trajectories were well above the boundary layer, where the mineral aerosol samples were collected. Stokes's law was used in the calculation of nonisentropic trajectories that incorporated the gravitational settling of aerosol particles. These trajectories, which began in the boundary layer, were calculated from a combination of lower-level and upper-level wind fields, and more accurately represented the wind fields that transported Saharan dust to Barbados. The Stokes's law trajectories for 4-µm aerosol particles reached a maximum in transport from northern Africa during the summer, which was also when the highest Al concentrations were observed. The Stokes's law trajectories for 4-µm aerosol particles indicated northern Africa as the source region for 55% of the high Al samples, while the equivalent value was only 9% for the 2-µm aerosols trajectories. Dust samples collected at Barbados have a smaller mean radius than the calculation required, indicating that other vertical motions are important during transport in addition to gravitational settling. However, up to 20% of the dust sampled at Barbados is in the size range used (4 µm).
Meteorology and Forest Fires: Conditions for Ignition and Conditions for Development
Authors: Martín L. Delgado , Diez A. García , Soriano L. Rivas , Diez E. L. García
Published: August 2010

Following the theoretical model proposed in previous papers in which four types of days and their associated fire risk (daily fire risk, DFR) were defined for each size of fire, the authors conclude that the meteorological conditions that favor the generation of fires must be similar to those that are favorable to their development. In a study of burned areas, comparative results with previous works are obtained, and the parameters DFR and NDFR (normalized DFR) are proven to be in agreement with their previously assigned physical meaning. The development rather than the ignition of forest fires is better described using the DFR and NDFR parameters.
Longwave Radiation on Snow-Covered Mountainous Surfaces
Authors: Plüss Christian , Ohmura Atsumu
Published: August 2010

Longwave radiation in snow-covered alpine environments was investigated based on LOWTRAN7 calculations. The irradiance from the sky and from the surrounding topography were determined separately in order to detect the influence of the topography on longwave radiation balance. Sensitivity studies showed that the irradiance from the surrounding terrain is determined primarily by the atmospheric conditions within the investigated area and by the surface temperature of the surrounding terrain. In snow-covered environments, the air temperature is usually above the snow surface temperature and the effects of the air between the topography and the receiving surface may be relevant.

Longwave irradiance from the surrounding terrain is an important component of the energy balance at the snow surface on inclined slopes and should be considered for areal investigations. A simple parameterization that accounts for the effects of the air is proposed for efficient calculation of longwave irradiance from snow-covered topography.
On the Potential Impact of Irrigated Areas in North America on Summer Rainfall Caused by Large-Scale Systems
Authors: Segal M. , Pan Z. , Turner R. W. , Takle E. S.
Published: August 2010

The potential impact of the increase in irrigated areas in North America during the past 100 years on summer rainfall associated with medium- to large-scale precipitation systems is evaluated conceptually and by several illustrative numerical model simulations. The model results for the simulated cases suggest a tendency toward some increase in the continental-average rainfall for the present irrigation conditions compared with those of past irrigation. The maximum increase obtained for several studied cases of 6-day duration each was 1.7%. Rainfall increases typically occur in the location of existing rainfall areas, and the main effect of irrigation is to redistribute rainfall in those preexisting precipitation regions.
Estimation of Surface and Top-of-Atmosphere Shortwave Irradiance in Biomass-Burning Regions during SCAR-B
Authors: Christopher Sundar A. , Li Xiang , Welch Ronald M. , Reid Jeffrey S. , Hobbs Peter V. , Eck Thomas F. , Holben Brent
Published: August 2010

Using in situ measurements of aerosol optical properties and ground-based measurements of aerosol optical thickness (τs) during the Smoke, Clouds and Radiation—Brazil (SCAR-B) experiment, a four-stream broadband radiative transfer model is used to estimate the downward shortwave irradiance (DSWI) and top-of-atmosphere (TOA) shortwave aerosol radiative forcing (SWARF) in cloud-free regions dominated by smoke from biomass burning in Brazil. The calculated DSWI values are compared with broadband pyranometer measurements made at the surface. The results show that, for two days when near-coincident measurements of single-scattering albedo ω0 and τs are available, the root-mean-square errors between the measured and calculated DSWI for daytime data are within 30 W m−2. For five days during SCAR-B, however, when assumptions about ω0 have to be made and also when τs was significantly higher, the differences can be as large as 100 W m−2. At TOA, the SWARF per unit optical thickness ranges from −20 to −60 W m−2 over four major ecosystems in South America. The results show that τs and ω0 are the two most important parameters that affect DSWI calculations. For SWARF values, surface albedos also play an important role. It is shown that ω0 must be known within 0.05 and τs at 0.55 μm must be known to within 0.1 to estimate DSWI to within 20 W m−2. The methodology described in this paper could serve as a potential strategy for determining DSWI values in the presence of aerosols. The wavelength dependence of τs and ω0 over the entire shortwave spectrum is needed to improve radiative transfer calculations. If global retrievals of DSWI and SWARF from satellite measurements are to be performed in the presence of biomass-burning aerosols on a routine basis, a concerted effort should be made to develop methodologies for estimating ω0 and τs from satellite and ground-based measurements.
Cloud Particle Phase Determination with the AVHRR
Authors: Key Jeffrey R. , Intrieri Janet M.
Published: August 2010

An accurate determination of cloud particle phase is required for the retrieval of other cloud properties from satellite and for radiative flux calculations in climate models. The physical principles underlying phase determination using the advanced very high resolution radiometer (AVHRR) satellite sensor are described for daytime and nighttime, cold cloud and warm cloud conditions. It is demonstrated that the spectral properties of cloud particles provide necessary, but not sufficient, information for phase determination, because the relationship between the cloud and surface temperatures is also important. Algorithms based on these principles are presented and tested. Validation with lidar and aircraft data from two Arctic field experiments shows the procedures to be accurate in identifying the phase of homogeneous water and ice clouds, though optically thin, mixed-phase, and multilayer clouds are problematic.