bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of the density dependence of the shear relaxation time of dense fluids
Authors: Bamdad Mehrdad , Alavi Saman , Najafi Bijan , Keshavarzi Ezat
Published: March 2005

The shear relaxation time, a key quantity in the theory of viscosity, is calculated for the LennardJones fluid and fluid krypton. The shear relaxation time is initially calculated by the ZwanzigMountain method, which defines this quantity as the ratio of the shear viscosity coefficient to the infinite shear modulus. The shear modulus is calculated from highly accurate radial distribution functions obtained from molecular dynamics simulations of the LennardJones potential and a realistic potential for krypton. This calculation shows that the density dependence of the shear relaxation time isotherms of the LennardJones fluid and Kr pass through a minimum. The minimum in the shear relaxation times is also obtained from calculations using the different approach originally proposed by van der Gulik. In this approach, the relaxation time is determined as the ratio of shear viscosity coefficient to the thermal pressure. The density of the minimum of the shear relaxation time is about twice the critical density and is equal to the common density, which was previously reported for supercritical gases where the viscosity of the gas becomes independent of temperature. It is shown that this common point occurs in both gas and liquid phases. At densities lower than this common density, even in the liquid state, the viscosity increases with increasing temperature.Key words: dense fluids, radial distribution function, shear modulus, shear relaxation time, shear viscosity.
Aromatization of 1,4-dihydropyridines with selenium dioxide
Authors: Cai Xiao-hua , Yang Hai-jun , Zhang Guo-lin
Published: March 2005

1,4-Dihydropyridines were aromatized to corresponding pyridines using stoichiometric selenium dioxide at ambient temperature in a yield of 87%~98%.Key words: 1,4-dihydropyridines, aromatization, oxidation, pyridine derivatives, selenium dioxide.
THERMAL QUANTUM FIELDS WITHOUT CUT-OFFS IN 1+1 SPACE-TIME DIMENSIONS
Authors: GÉRARD CHRISTIAN , JÄKEL CHRISTIAN D.
Published: March 2005

We construct interacting quantum fields in 1+1 dimensional Minkowski space, representing neutral scalar bosons at positive temperature. Our work is based on prior work by Klein and Landau and Høegh-Krohn.
SYSTEMS OF CLASSICAL PARTICLES IN THE GRAND CANONICAL ENSEMBLE, SCALING LIMITS AND QUANTUM FIELD THEORY
Authors: ALBEVERIO SERGIO , GOTTSCHALK HANNO , YOSHIDA MINORU W.
Published: March 2005

Euclidean quantum fields obtained as solutions of stochastic partial pseudo differential equations driven by a Poisson white noise have paths given by locally integrable functions. This makes it possible to define a class of ultra-violet finite local interactions for these models (in any space-time dimension). The corresponding interacting Euclidean quantum fields can be identified with systems of classical "charged" particles in the grand canonical ensemble with an interaction given by a nonlinear energy density of the "static field" generated by the particles' charges via a "generalized Poisson equation". A new definition of some well-known systems of statistical mechanics is given by formulating the related field theoretic local interactions. The infinite volume limit of such systems is discussed for models with trigonometric interactions using a representation of such models as Widom–Rowlinson models associated with (formal) Potts models at imaginary temperature. The infinite volume correlation functional of such Potts models can be constructed by a cluster expansion. This leads to the construction of extremal Gibbs measures with trigonometric interactions in the low-density high-temperature (LD-HT) regime. For Poissonian models with certain trigonometric interactions an extension of the well-known relation between the (massive) sine-Gordon model and the Yukawa particle gas connecting characteristic and correlation functionals is given and used to derive infinite volume measures for interacting Poisson quantum field models through an alternative route. The continuum limit of the particle systems under consideration is also investigated and the formal analogy with the scaling limit of renormalization group theory is pointed out. In some simple cases the question of (non-) triviality of the continuum limits is clarified.
Induction of Apoptosis in Human Oral Cancer Cell Lines, OC2 and TSCCa, by Chingwaysan
Authors: Liao Pao-Hsin , Chen Shiow-Ling , Shih Hung-Che , Chou Ming-Yung
Published: March 2005

Chingwaysan, a Chinese herbal formula, contains Cimicfugae Rhizoma, Rehmanniae Radixet Rhizoma, Moutan Radicis Cortex, Coptidis Rhizoma and Angelicae Sinensis Radix. This medicine is well-known for its curing power for ulcerated gums, toothaches, cheek boils and bleeding gingiva. However, no reports can be found on its application in the treatment of oral cancers. We are therefore interested in whether Chingwaysan is capable of causing abnormal apoptosis processes, and whether this condition can be rectified through Chingwaysan herb treatment. We used aqueous extract to treat OC2 and TSCCa cells (both are human oral cancer cell lines) with different Chingwaysan concentrations (0, 10, 25, 50, 75 and 100 μl/ml). The MTT (3, (4, 5-dimethyl-thiazol) 2, 5-diphenyl-tetraxolium bromide) reduction assay was employed to quantify the differences in cell activity and viability. DNA ladder formation on agarose electrophoresis was also performed. The bax expression level was monitored using immunoblotting techniques. The patterns of the changes in expression were scanned and analyzed by NIH image 1.56 software. Taken together, drastic morphological changes, reduced cell viability and the presence of inter-nucleosomal DNA fragmentation all indicated that Chingwaysan is capable of inducing apoptosis in OC2 and TSCCa cell lines. Furthermore, the accumulation of wild type bax protein significantly increased in a dose-dependent manner upon treatment with Chingwaysan. In conclusion, Chingwaysan can induce apoptosis via a bax-dependent pathway in cells from these two particular oral cancer cell lines.
Pharmacological Properties of N-095, a Drug Containing Red Ginseng, Polygala Root, Saffron, Antelope Horn and Aloe Wood
Authors: Inoue Eiji , Shimizu Yasuharu , Shoji Masamichi , Tsuchida Haruyo , Sano Yumiko , Ito Chihiro
Published: March 2005

This study sought to establish a pharmacological profile for N-095, a crude drug containing red ginseng, polygala root, saffron, antelope horn and aloe wood. Our studies on rats and mice revealed a number of pharmacological properties of this novel drug. N-095 increased the forced swimming time in mice and prevented gastric ulcers in rats under restraint and water immersion stress conditions at 100 mg/kg or higher. It also prevented footpad swelling in rats treated with λ-carrageenin and histamine-induced gastric ulcers in rats at 300 mg/kg or higher. Furthermore, N-095 augmented the sedative effect in mice induced by hexobarbital, which is characterized by a decreased spontaneous motor activity and a prolongation of sleeping time. N-095 also stimulated spontaneous contractility of the uterus in rats at 1000 mg/kg and 2000 mg/kg and prevented hemolysis of erythrocytes by heating. In contrast, N-095 had no effect on the respiratory or cardiovascular system or on water and electrolyte regulation in rats or mice. These results show that N-095 is a relatively safe drug for use as a nutrient or tonic.
Raising Harmonic Variation of Arterial Pulse in Dying Rats
Authors: Kuo Y. C. , Lo S. H. , Chao P. T. , Hsiu H. , Li S. P. , Wang W. K. , Lin Wang Y. Y.
Published: March 2005

Our previous study revealed that the coefficient of variation of harmonic magnitude (HCV) of radial arterial pulse was significantly raised before the death of cancer patients. In this study, we recorded the caudate arterial pulse of 24 Sprague-Dawley rats that had a fatal dose of urethane injected into their abdomens. Twenty rats were dead within 3 hours after the injection and four survived. We defined the last 100 minutes of each rat's life as the dying process. During the dying process, we found that both the systolic blood pressure and diastolic blood pressure dropped steeply during the last 5 minutes. However, all HCVs, except HCV1, climbed steeply before the last 5 minutes. The HCV1 of the dying rats was significantly higher than that of rats that survived, starting from the first minute (P<0.01). The HCV2 of the dying rats was significantly higher than that of the survived rats starting from the 52nd minute (P<0.05). The HCV3 and HCV4 of the dying rats were significantly higher than those of the survived rats until the 70th minute and the 80th minute, respectively (P<0.05). Furthermore, HCV2–HCV4 proceeded with the dying process and increased gradually. We concluded that HCVs, which failed first in the high-frequency components and then in the low-frequency components, could provide physicians with earlier information to prevent the coming failure of circulatory system, and could reflect quantitatively pathological severity and predict patient outcome. The specific Fourier components in the pulse provide more physiological information than systolic and diastolic blood pressures.
Efficacy of the Kampo Medicine Xiong-gui-tiao-xue-yin (Kyuki-chouketsu-in), a Traditional Herbal Medicine, in the Treatment of Maternity Blues Syndrome in the Postpartum Period
Authors: Ushiroyama Takahisa , Sakuma Kou , Ueki Minoru
Published: March 2005

This study was to evaluate the clinical efficacy of Xiong-gui-tiao-xue-yin (Kyuki-chouketsu-in), a Japanese traditional herbal medicine, in stabilizing postpartum psychological state. We enrolled 268 women who had a normal delivery in Osaka Medical College Hospital or its affiliated clinics and randomly assigned them to the following two groups: a group of 134 women who received Xiong-gui-tiao-xue-yin (Kyuki-chouketsu-in) at a dose of 6.0 g/day and another group of 134 women without Xiong-gui-tiao-xue-yin (Kyuki-chouketsu-in) (control group). We observed 2.06-fold and 1.67-fold higher incidences of depressive mood and nervousness, respectively, after delivery in the control group than in the Xiong-gui-tiao-xue-yin (Kyuki-chouketsu-in) group. Within 3 weeks of postpartum, there was a significant difference in the incidences of maternity blues between the Xiong-gui-tiao-xue-yin (Kyuki-chouketsu-in) group (15.7%; 21/134) and the control group (32.1%; 43/134) (p=0.0195). No adverse effects were observed in this study. The results of this study demonstrate the beneficial clinical effects of Xiong-gui-tiao-xue-yin (Kyuki-chouketsu-in) in stabilizing psychological state in the postpartum period.

Xiong-gui-tiao-xue-yin (Kyuki-chouketsu-in) can be expected to improve the mental health of women in the postpartum period and prevent maternity blues.
Qi Therapy (External Qigong) for Chronic Fatigue Syndrome: Case Studies
Authors: Shin Yong-Il , Lee Myeong Soo
Published: March 2005

The aim of this study was to examine the effects of Qi therapy (QT) on the symptoms of chronic fatigue syndrome (CFS), including fatigue and complications. QT affected the experience of mental and emotional relaxation in the subjects of these case studies, who also gained strength to overcome their pain and fatigue. Although the results of these two case studies may not constitute conclusive evidence, they provide a foundation for the exploration of QT as a complementary therapy in the reduction of negative symptoms of chronic fatigue syndrome.
The Antinociceptive Effect of Acupressure in Rats
Authors: Trentini John F. , Thompson B. , Erlichman Joseph S.
Published: March 2005

Acupuncture and acupressure points correlate well with sites on the body that have low transcutaneous electrical resistance (TER). Using lightly sedated, adult Sprague-Dawley rats, we identified an acupoint (i.e. site with low TER) located on the hind limb of the rat and compared the effects of acupressure at this site on the nociceptive threshold to an adjacent, non-acupoint site (i.e. site with high TER). Focal pressure (55.42±2.2 g) was applied to the site for 10 minutes and the tail flick response (TFR) was determined by draping the distal portion of the tail over a heated wire (75±5°C). Three trials were performed during each of three randomized conditions (i.e. acupoint, placebo and control) and the trials were averaged. All rats tested (5/5) showed a statistically significant increase in TFR following 10 minutes of acupressure at the acupoint compared to placebo or control trials (p=0.007). Acupressure at the placebo point resulted in a TFR that was not statistically different from the control. Systemic administration of naloxone completely abolished the tail-flick inhibition induced by acupressure at the acupoint. These data suggest that acupressure elicits an antinociceptive effect in rats that is mediated by the endogenous release of opioids.
TESTING OF REAL CONVERGENCE IN GERMANY IN THE PRESENCE OF STRUCTURAL BREAKS
Authors: GIL-ALANA L. A.
Published: March 2005

In this short article we examine the real convergence hypothesis in Germany with respect to the US by means of fractional integration. Using a parametric procedure due to Robinson (1994), the results show that real convergence is only achieved in this country if we take into account the presence of a structural break at World War II. The same evidence is found in other countries (like Japan, the UK and Canada) when this break is considered.
THE EFFECT OF THE SEMICONDUCTOR TRADE AGREEMENT ON JAPANESE FIRMS
Authors: PARSONS CRAIG
Published: March 2005

This paper investigates the impact of the 1986 US-Japan Semiconductor Trade Agreement (STA) and antidumping actions by the US on Japanese firms. We conduct an event study employing WLS and OLS estimations on the daily returns of eight large electronics firms over roughly a two year period. We find that the STA had a positive effect on the daily returns while the antidumping rulings were found to be insignificant. These results are consistent with some authors' views that the STA policy may have facilitated collusive behavior to the benefit of not only US, but Japanese firms as well. These results shed some light on the ambiguous results found in the Voluntary Import Expansion (VIE) literature.
THE ROLE OF THE STATE IN THE INCREASINGLY GLOBALIZED ECONOMY: IMPLICATIONS FOR SINGAPORE
Authors: SHIN JANG-SUP
Published: March 2005

This paper argues that the role of the state becomes more important in some significant respects as the pace of globalization accelerates, contrary to the popular perception that it should be diminished. This is mainly because, as mobile factors obtain more freedom to choose locations across national borders, the role of the state as the ultimate provider of "complementary assets" in attracting mobile factors to a national economy becomes more important. The paper also argues that the very success of Singapore's complementing strategy in the era of globalization has necessitated the state to move to a two-pronged strategy, in which it needs to attempt seriously to acquire higher-end capabilities that are securely based on its territory, while trying to exploit ever-expanding complementary business areas as it has done previously.
GLOBAL THEORY OF QUANTUM BOUNDARY CONDITIONS AND TOPOLOGY CHANGE
Authors: ASOREY M. , IBORT A. , MARMO G.
Published: March 2005

We analyze the global theory of boundary conditions for a constrained quantum system with classical configuration space a compact Riemannian manifold M with regular boundary Γ=∂M. The space ℳ of self-adjoint extensions of the covariant Laplacian on M is shown to have interesting geometrical and topological properties which are related to the different topological closures of M. In this sense, the change of topology of M is connected with the nontrivial structure of ℳ. The space ℳ itself can be identified with the unitary group [Formula: see text] of the Hilbert space of boundary data [Formula: see text]. This description, is shown to be equivalent to the classical von Neumann's description in terms of deficiency index subspaces, but it is more efficient and explicit because it is given only in terms of the boundary data, which are the natural external inputs of the system. A particularly interesting family of boundary conditions, identified as the set of unitary operators which are singular under the Cayley transform, [Formula: see text] (the Cayley manifold), turns out to play a relevant role in topology change phenomena. The singularity of the Cayley transform implies that some energy levels, usually associated with edge states, acquire an infinity energy when by an adiabatic change the boundary conditions reaches the Cayley submanifold 𝒞_. In this sense topological transitions require an infinite amount of quantum energy to occur, although the description of the topological transition in the space ℳ is smooth. This fact has relevant implications in string theory for possible scenarios with joint descriptions of open and closed strings. In the particular case of elliptic self-adjoint boundary conditions, the space 𝒞_ can be identified with a Lagrangian submanifold of the infinite dimensional Grassmannian. The corresponding Cayley manifold 𝒞_ is dual of the Maslov class of ℳ. The phenomena are illustrated with some simple low dimensional examples.
SUMMATION OF HIGHER ORDER EFFECTS USING THE RENORMALIZATION GROUP EQUATION
Authors: ELIAS V. , McKEON D. G. C. , SHERRY T. N.
Published: March 2005

The renormalization group (RG) is known to provide information about radiative corrections beyond the order in perturbation theory to which one has calculated explicitly. We first demonstrate the effect of the renormalization scheme used on these higher order effects determined by the RG. Particular attention is paid to the relationship between bare and renormalized quantities. Application of the method of characteristics to the RG equation to determine higher order effects is discussed and used to examine the free energy in thermal field theory, the relationship between the bare and renormalized coupling, and the effective potential in massless scalar electrodynamics.
THE GENERAL TWISTED OPEN WZW STRING
Authors: HALPERN M. B. , HELFGOTT C.
Published: March 2005

We recently studied two large but disjoint classes of twisted open WZW strings: the open-string sectors of the WZW orientation orbifolds and the so-called basic class of twisted open WZW strings. In this paper, we discuss all T-dualizations of the basic class to construct the general twisted open WZW string — which includes the disjoint classes above as special cases. For the general case, we give the branes and twisted noncommutative geometry at the classical level and the twisted open-string KZ equations at the operator level. Many examples of the general construction are discussed, including in particular the simple case of twisted free-bosonic open strings. We also revisit the open-string sectors of the general WZW orientation orbifold in further detail. For completeness, we finally review the general twisted boundary state equation which provides a complementary description of the general twisted open WZW string.
CONFORMAL ANOMALIES FOR INTERACTING SCALAR FIELDS ON CURVED MANIFOLDS WITH BOUNDARY
Authors: TSOUPROS GEORGE
Published: March 2005

The trace anomaly for a conformally invariant scalar field theory on a curved manifold of positive constant curvature with boundary is considered. In the context of a perturbative evaluation of the theory's effective action explicit calculations are given for those contributions to the conformal anomaly which emerge as a result of free scalar propagation as well as from scalar self-interactions up to second order in the scalar self-coupling. The renormalization-group behavior of the theory is, subsequently, exploited in order to advance the evaluation of the conformal anomaly to third order in the scalar self-coupling. As a direct consequence the effective action is evaluated to the same order. In effect, complete contributions to the theory's conformal anomaly and effective action are evaluated up to fourth-loop order.
Insulin-activated, K+-channel-sensitive Akt pathway is primary mediator of ML-1 cell proliferation
Authors: Guo Taylor B. , Lu Jiawei , Li Tie , Lu Zhenyu , Xu Guotong , Xu Ming , Lu Luo , Dai Wei
Published: March 2005

Voltage-gated K+channel activities are involved in regulating growth factor-stimulated cell proliferation in a variety of cell types. Here we report that suppression of a voltage-gated K+channel with 4-aminopyridine (4-AP), barium, and tetraethylammonium inhibited both EGF- and insulin-stimulated myeloblastic leukemia ML-1 cell proliferation in a concentration-dependent manner. Both MAPK/ERK and Akt pathways are known to mediate cell proliferative signals of a variety of growth factors including insulin. In serum-starved ML-1 cells, insulin rapidly stimulated phosphorylation of ERK1/2 and Akt, and the phosphorylation levels peaked ∼30 min after treatment. Pretreatment of ML-1 cells with 4-AP potently and dose-dependently prevented phosphorylation of ERK1/2 and Akt. However, insulin-induced activation of the Akt pathway also played a role in promoting ML-1 cell proliferation. Flow cytometry analysis revealed that although ML-1 cells were primarily arrested at G1phase by serum starvation for 36 h, they reentered the cell cycle after treatment with serum or insulin for 24 h. However, concomitant 4-AP treatment was able to attenuate cell cycle progression in synchronized ML-1 cells stimulated with growth factors. Our results strongly suggest that a 4-AP-sensitive K+channel activity plays an important role in controlling proliferation of ML-1 cells by affecting the activation of multiple signal transduction processes induced by insulin.
SLC26A9 is expressed in gastric surface epithelial cells, mediates Cl−/HCO3− exchange, and is inhibited by NH4+
Authors: Xu Jie , Henriksnäs Johanna , Barone Sharon , Witte David , Shull Gary E. , Forte John G. , Holm Lena , Soleimani Manoocher
Published: March 2005

HCO3− secretion by gastric mucous cells is essential for protection against acidic injury and peptic ulcer. Herein we report the identification of an apical HCO3− transporter in gastric surface epithelial cells. Northern hybridization and RT-PCR demonstrate the expression of this transporter, also known as SLC26A9, in mouse and rat stomach and trachea (but not kidney). In situ hybridization in mouse stomach showed abundant expression of SLC26A9 in surface epithelial cells with apical localization on immunofluorescence labeling. Functional studies in HEK-293 cells demonstrated that SLC26A9 mediates Cl−/HCO3− exchange and is also capable of Cl−-independent HCO3− extrusion. Unlike other anion exchangers or transport proteins reported to date, SLC26A9 activity is inhibited by ammonium (NH4+). The inhibitory effect of NH4+ on gastric HCO3− secretion was also indicated by reduced gastric juxtamucosal pH (pHjm) in rat stomach in vivo. This report is the first to describe the inhibition of HCO3− transport in vitro and the reduction of pHjm in stomach in vivo by NH4+. Given its critical localization on the apical membrane of surface epithelial cells, its ability to transport HCO3−, and its inhibition by NH4+, we propose that SLC26A9 mediates HCO3− secretion in surface epithelial cells and is essential for protection against acidic injury in the stomach. Disease states that are associated with increased ammonia (NH3)/NH4+ generation (e.g., Helicobacter pylori) may impair gastric HCO3− secretion and therefore predispose patients to peptic ulcer by inhibiting SLC26A9.
Effect of physical activity on MRI-measured blood oxygen level-dependent transients in skeletal muscle after brief contractions
Authors: Towse Theodore F. , Slade Jill M. , Meyer Ronald A.
Published: March 2005

The signal intensity (SI) in gradient-echo, echo-planar magnetic resonance images (repetition time/echo time = 1,000/40) of anterior tibialis muscle in active [estimated energy expenditure 42.4 ± 3.7 (SD), n = 8] vs. sedentary (32.3 ± 0.6 kcal·kg−1·day−1, n = 8) young adult (18–34 yr old) human subjects was measured after single, 1-s-duration maximum voluntary ankle dorsiflexion contractions. There was no difference between groups in anterior tibial muscle cross-sectional area or peak force. In both groups there was a transient increase in anterior tibialis muscle SI, which peaked 5–7 s after the end of each contraction. The magnitude of the SI transient was over threefold greater [5.5 ± 1.0 (SE) vs. 1.5 ± 0.4%] and persisted twice as long (half-recovery time 5.4 ± 0.4 vs. 2.7 ± 0.3 s) in the active subjects. In the same subjects, blood flow in popliteal, anterior tibial, and posterior tibial arteries was measured by cardiac-gated CINE magnetic resonance angiography before and after 2 min of dynamic, repetitive ankle dorsiflexion exercise. There was no difference between groups in resting or postexercise flow in anterior tibial artery, although popliteal and posterior tibial artery flow after exercise tended to be greater in the active group. The results indicate that transient hyperemia and oxygenation in muscle after single contractions are enhanced by chronic physical activity to a greater extent than peak muscle blood flow.
Effect of pulmonary perfusion on the slopes of single-breath test of CO2
Authors: Tusman G. , Areta M. , Climente C. , Plit R. , Suarez-Sipmann F. , Rodríguez-Nieto M. J. , Peces-Barba G. , Turchetto E. , Böhm S. H.
Published: March 2005

The objective of this study was to evaluate the effects of lung perfusion on the slopes of phases II ( SII) and III ( SIII) of a single-breath test of CO2 (SBT-CO2). Fourteen patients submitted to cardiac surgery were studied during weaning from cardiopulmonary bypass (CPB). Pump flow was decreased in 20% steps, from 100% (total CPB = 2.5 l·min−1·m−2) to 0%. This maneuver resulted in a progressive and opposite increase in pulmonary blood flow (PBF) while maintaining ventilator settings constant. SBT-CO2, respiratory, and hemodynamic variables remained unchanged before and after CPB, reflecting a constant condition at those stages. SIII was similar before and after CPB (19.6 ± 2.8 and 18.7 ± 2.1 mmHg/l, respectively). SIII was lowest during 20% PBF (8.6 ± 1.9 mmHg/l) and increased in proportion to PBF until exit from CPB (15.6 ± 2.2 mmHg/l; P < 0.05). Similarly, SII and the CO2 area under the curve increased from 163 ± 41 mmHg/l and 4.7 ± 0.6 ml, respectively, at 20% PBF to 313 ± 32 mmHg/l and 7.9 ± 0.6 ml ( P < 0.05) at CPB end. When SII and SIII were normalized by the mean percent expired CO2, they remained unchanged during the protocol. In summary, the changes in PBF affect the slopes of the SBT-CO2. Normalizing SII and SIII eliminated the effect of changes in the magnitude of PBF on the shape of the SBT-CO2 curve.
Corticotrophin-Releasing Factor Augments the IH in Rat Hypothalamic Paraventricular Nucleus Parvocellular Neurons In Vitro
Authors: Qiu De-Lai , Chu Chun-Ping , Shirasaka Tetsuro , Tsukino Hiromasa , Nakao Hiroyuki , Kato Kazuo , Kunitake Takato , Katoh Takahiko , Kannan Hiroshi
Published: March 2005

The goal of this study was to characterize the effects of corticotrophin-releasing factor (CRF) on rat paraventricular nucleus (PVN) putative parvocellular neurons using whole cell patch-clamp recordings and single-cell reverse transcription-multiplex polymerase chain reaction (single-cell RT-mPCR) techniques. Under current clamp, CRF (10–600 nM) increased the neuronal basal firing rate and depolarized neurons in a dose-dependent manner. CRF-induced depolarization was unaffected by co-perfusion with TTX, 6-cyano-7-nitroquinoxaline-2 3-dione (CNQX), and bicuculline but was completely inhibited by ZD7288. Under voltage clamp, 300 nM CRF significantly increased the hyperpolarization-activated cation current ( IH) in a voltage-dependent manner, shifted the IH conductance-voltage relationship ( V1/2) toward depolarization by ∼7.8 mV, and enhanced the IH kinetics without changing the slope constant (k). Extracellular application of ZD7288 completely blocked IH and the CRF-induced increase in IH. Furthermore, CRF-induced effects were completely blocked by extracellular application of 1 μM α-helical CRF-(9–14) (α-hCRF), a nonselective CRF receptor antagonist, but were not affected by extracellular application of antisauvagine-30, a selective CRF-receptor 2 antagonist. Single-cell RT-mPCR analysis showed that these neurons co-expressed CRF receptor 1 mRNA and CRF receptor 2 mRNA. Furthermore, CRF-sensitive neurons co-expressed HCN1 channel mRNA, HCN2 channel mRNA, and HCN3 channel mRNA, but not HCN4 channel mRNA. These results suggest that CRF modulates the subpopulation of PVN parvocellular neuronal function by CRF-receptor 1–mediated potentiation of HCN ion channel activity.
Predicting the Onset of Australian Winter Rainfall by Nonlinear Classification
Authors: Firth Laura , Hazelton Martin L. , Campbell Edward P.
Published: March 2005

A method for predicting the timing of winter rains is presented, making no assumptions about the functional form of any relationships that may exist. Ideas built on classification and regression trees and machine learning are used to develop robust predictive rules. These methods are applied in a case study to predict the timing of winter rain in five farming towns in the southwest of Western Australia. The variables used to construct the model are mean monthly sea surface temperatures (SSTs) over a 72-cell grid in the Indian Ocean, Perth monthly mean sea level pressure (MSLP), and monthly values of the Southern Oscillation index (SOI). A predictive model is constructed from data over the period 1949–99. This model correctly classifies the onset of the winter rains approximately 80% of the time with SST variables proving to be the most important in deriving the predictions. Further analysis indicates a change point in the mid-1970s, a well-known phenomenon in the region. The prediction rates are significantly worse after 1975. Furthermore, the important region of the Indian Ocean, in terms of SSTs for prediction, moves from the Tropics down toward the Southern Ocean after this date.
Statistical Modeling of Extreme Rainfall in Southwest Western Australia
Authors: Li Y. , Cai W. , Campbell E. P.
Published: March 2005

Rainfall over southwest Western Australia (SWWA; 32°S southward and 118°E westward) has been decreasing over the past decades, putting further constraints on water resources in an already dry area. In this study, daily rainfall over five geographically dispersed and homogenized weather stations within SWWA are analyzed. A peak over threshold method from the extreme value theory is used to model daily rainfall above a given threshold. The Mann–Whitney–Pittitt (change point) test was applied to detect changes in annual, winter (May–October), and summer (November–April) maximum daily rainfall. Change points for winter extreme daily rainfall were found around 1965, based on different individual stations, with the extreme daily rainfall reduced since then. To demonstrate the degree of change in the winter extreme daily rainfall, at 1965 the data were stratified, and generalized Pareto distributions were fitted to the tails of the distributions for daily rainfall in the prechange period of 1930–65 (including 1965) and the postchange period of 1966–2001. The fitted tail distributions also allow the estimation of probabilities and return periods of the daily rainfall extreme. Results show that return periods for the winter extreme daily rainfall have increased after 1965, implying that winter daily rainfall extremes in SWWA are lower after 1965 than they were before. There has been vigorous debate as to what forces the drying trend, that is, whether it is part of multidecadal variability or whether it is driven by secular forcings, such as increasing atmospheric CO2 concentration. In this paper, statistical modeling is also used to identify possible associated changes in atmospheric circulation. It is found that there is a change point near 1965 in a dominant atmospheric circulation mode of the Antarctic Oscillation (AAO). The result offers qualified support for the argument that the AAO may contribute to the drying trend.
The Mass of the Atmosphere: A Constraint on Global Analyses
Authors: Trenberth Kevin E. , Smith Lesley
Published: March 2005

The total mass of the atmosphere varies mainly from changes in water vapor loading; the former is proportional to global mean surface pressure and the water vapor component is computed directly from specific humidity and precipitable water using the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analyses (ERA-40). Their difference, the mass of the dry atmosphere, is estimated to be constant for the equivalent surface pressure to within 0.01 hPa based on changes in atmospheric composition. Global reanalyses satisfy this constraint for monthly means for 1979–2001 with a standard deviation of 0.065 hPa. New estimates of the total mass of the atmosphere and its dry component, and their corresponding surface pressures, are larger than previous estimates owing to new topography of the earth’s surface that is 5.5 m lower for the global mean. Global mean total surface pressure is 985.50 hPa, 0.9 hPa higher than previous best estimates. The total mean mass of the atmosphere is 5.1480 × 1018 kg with an annual range due to water vapor of 1.2 or 1.5 × 1015 kg depending on whether surface pressure or water vapor data are used; this is somewhat smaller than the previous estimate. The mean mass of water vapor is estimated as 1.27 × 1016 kg and the dry air mass as 5.1352 ± 0.0003 × 1018 kg. The water vapor contribution varies with an annual cycle of 0.29-hPa, a maximum in July of 2.62 hPa, and a minimum in December of 2.33 hPa, although the total global surface pressure has a slightly smaller range. During the 1982/83 and 1997/98 El Niño events, water vapor amounts and thus total mass increased by about 0.1 hPa in surface pressure or 0.5 × 1015 kg for several months. Some evidence exists for slight decreases following the Mount Pinatubo eruption in 1991 and also for upward trends associated with increasing global mean temperatures, but uncertainties due to the changing observing system compromise the evidence.

The physical constraint of conservation of dry air mass is violated in the reanalyses with increasing magnitude prior to the assimilation of satellite data in both ERA-40 and the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalyses. The problem areas are shown to occur especially over the Southern Oceans. Substantial spurious changes are also found in surface pressures due to water vapor, especially in the Tropics and subtropics prior to 1979.
Analysis of Sampling Errors for Climate Monitoring Satellites
Authors: Kirk-Davidoff Daniel B. , Goody Richard M. , Anderson James G.
Published: March 2005

Sampling retrievals of high-accuracy first-moment statistics constitute a central concern for climate research. Considered here is the important case of brightness temperature retrievals from a selection of possible orbits. Three-hourly global satellite brightness temperature data are used to predict the sampling error of monthly to annual mean brightness temperature retrieved by one or more satellites in low earth orbits. A true polar orbit is found to offer substantial advantages over a sun-synchronous orbit in the retrieval of annual mean brightness temperature, since the rotation of the local time of observation through two full diurnal cycles greatly reduces the error due to imperfect sampling of diurnal variations. Thus, a single polar orbiting satellite can produce annual mean, zonal mean brightness temperatures with typical sampling errors of less than 0.1 K, while even three sun-synchronous orbiters have high-latitude errors of up to 0.4 K. The error in retrievals of the annual mean diurnal cycle of brightness temperature is also discussed. In this case, high accuracy (<0.1 K) requires three cross-track scanning satellites in precessing orbits, or else a very large number (∼10) of nadir-viewing satellites in precessing orbits. The large sampling errors of sun-synchronous satellites are highly correlated from year to year, so that if equator-crossing times are held fixed, sampling errors in year-to-year differences of annual means are similar for sun-synchronous and precessing orbits.
Roles of Low- and High-Frequency Eddies in the Transitional Process of the Southern Hemisphere Annular Mode
Authors: Shiogama Hideo , Terao Toru , Kida Hideji , Iwashima Tatsuya
Published: March 2005

The effects of low- and high-frequency eddies (time scales longer and shorter than 10 days, respectively) on the transitional processes of the Southern Hemisphere “Annular Mode” are investigated, based on NCEP–NCAR daily reanalysis data for the period 1979–2001. Special attention is focused on the zonal symmetry/asymmetry and the temporal evolution of the eddy forcing.

For the poleward transitional process, the effects of low-frequency eddies precede those of high-frequency eddies in driving the jet transition. Quasi-stationary Rossby waves propagating along the polar jet with wavelengths of 7000 km play an important role. The waves, originally come from the Indian Ocean through the waveguide associated with the polar jet, dissipate equatorward over the eastern Pacific Ocean. This anomalous equatorward dissipation of wave activity induces an anomalous poleward momentum flux, which is responsible for changes in the polar jet over the Pacific Ocean during the beginning stage. Following the low-frequency eddy forcing, momentum forcing anomalies due to the high-frequency eddies rapidly appear. This forcing continues to drive the polar jet poleward over the whole of longitude, while the low-frequency eddies have completed their role of inducing the anomalous poleward momentum flux during the earlier stage.

For the equatorward transitional events, the roles of the low-frequency eddy forcing differ from that in the poleward ones. Anomalous equatorward momentum fluxes due to low-frequency eddies appear simultaneously with that due to high-frequency eddies. Quasi-stationary Rossby waves with wavelengths of 7000 km propagate southeastward through the waveguide over the Pacific Ocean. The convergence of their wave activity results in the deceleration of the westerlies over the higher latitudes of the Pacific Ocean. On the other hand, the high-frequency eddy forcing contributes to the equatorward jet drift longitudinally over the whole of the hemisphere.
Hot Spots Policing Experiments and Criminal Justice Research: Lessons from the Field
Authors: Weisburd David
Published: March 2005

In this article, more general lessons are drawn from two randomized experiments in hot spots policing that the author helped design and implement in the 1990s: the Minneapolis Hot Spots Experiment and the Jersey City Drug Market Analysis Experiment. Using a case study approach, factors that facilitate and inhibit development and implementation of randomized trials are identified with particular focus on the special problems and/or advantages of place-based experiments. While the author's main comments focus on the success of place-based randomized trials in evaluating hot spots policing approaches, he draws insight as well into the reasons why the successful example of experiments in hot spots policing has not inspired similar place-based experimentation in other areas of policing or criminal justice. Eight specific lessons regarding the implementation and development of place-based randomized trials and experimental methods more generally are identified.
Place-Based Randomized Trials to Test the Effects on Instructional Practices of a Mathematics/ Science Professional Development Program for Teachers
Authors: Porter Andrew C. , Blank Rolf K. , Smithson John L. , Osthoff Eric
Published: March 2005

Aprofessional development model was designed for and is being tested in approximately fifty U.S. middle schools in five large urban districts, with half in each district randomly assigned to receive the two-year treatment. Each school forms a mathematics/science leadership team of five to seven members, including at least one administrator. Teams receive professional development in district-level workshops, then work with all math and science teachers in their school. The core idea is to provide teachers with data on their instructional practices and student achievement, then teach them how to use that data to improve their effectiveness. This article documents the successes and failures of treatment implementation and the collection of baseline and outcome data. The focus is on learning about doing place-based randomized trials to test the efficacy of education programs. At the time of this writing, treatment is not yet complete and study results are not available.
Using Place-Based Random Assignment and Comparative Interrupted Time-Series Analysis to Evaluate the Jobs-Plus Employment Program for Public Housing Residents
Authors: Bloom Howard S. , Riccio James A.
Published: March 2005

This article describes a place-based research demonstration program to promote and sustain employment among residents of selected public housing developments in six U.S. cities. Because all eligible residents of the participating public housing developments were free to take part in the program, it was not possible to study its impacts in a classical experiment, with random assignment of individual residents to the program or a control group. Instead, the impact analysis is based on a design that selected matched groups of two or three public housing developments in each participating city and randomly assigned one to the program and the other(s) to a control group. In addition, an eleven-year comparative interrupted time-series analysis is being used to strengthen the place-based random assignment design. Preliminary analyses of baseline data suggest that this two-pronged approach will provide credible estimates of program impacts.
Emergent Principles for the Design, Implementation, and Analysis of Cluster-Based Experiments in Social Science
Authors: Cook Thomas D.
Published: March 2005

In experimentally designed research, many good reasons exist for assigning groups or clusters to treatments rather than individuals. This article discusses them. But cluster-level designs face some unique or exacerbated challenges. The article identifies them and offers some principles about them. One emphasizes how statistical power and sample size estimation depend on intraclass correlations, particularly after conditioning on the use of cluster-level covariates. Another stresses assigning experimental units at the lowest level of aggregation possible, provided this does not subtly change the research question. A third emphasizes the utility of minimizing and measuring interunit communication, though neither is easy to achieve. A fourth advises against experiments that are totally black box and so leave program implementation and process unstudied, though such study often makes the research process more salient. The last principle involves the utility of describing treatment heterogeneity and estimating its consequences, though causal conclusions about the heterogeneity will be less well warranted compared to conclusions about the intended treatment, every experiment's major focus.
The Effects of Social Change Within a Group on Membership Preferences: To Leave or Not to Leave?
Authors: Prislin Radmila , Christensen P. Niels
Published: March 2005

Two studies examined immediate (Study 1) and long-term (Study 2) behavioral consequences of previously documented asymmetries in cognitive and evaluative reactions to change in majority and minority positions within a group. Study 1 found an overall decrease in preferences for group membership immediately following change, which was preceded by decategorization and devaluation of the group in response to loss, together with lack of categorization and positive evaluation in response to gain of the majority position. Study 2 found a gradual increase in preference to stay with (vs. exit) the group among former minorities with prolonged interactions that confirmed their gained majority position. A gradual increase in preference for group membership was paralleled with gradual increases in perception of both inclusion within and differentiation from the group.
Self-Affirmation and Mortality Salience: Affirming Values Reduces Worldview Defense and Death-Thought Accessibility
Authors: Schmeichel Brandon J. , Martens Andy
Published: March 2005

To the extent that cultural worldviews provide meaning in the face of existential concerns, specifically the inevitability of death, affirming a valued aspect of one’s worldview should render reminders of death less threatening. The authors report two studies in support of this view. In Study 1, mortality salience led to derogation of a worldview violator unless participants had first affirmed an important value. In Study 2, self-affirmation before a reminder of death was associated with reduced accessibility of death-related thoughts a short while thereafter. The authors propose that actively affirming one’s worldview alters reactions to reminders of mortality by reducing the accessibility of death-related thoughts, not by boosting self-esteem. These studies attest to the flexible nature of psychological self-defense and to the central role of cultural worldviews in managing death-related concerns.
Myopic Biases in Strategic Social Prediction: Why Deadlines Put Everyone Under More Pressure Than Everyone Else
Authors: Moore Don A.
Published: March 2005

Five experiments document biases in the way people predict the outcomes of interdependent social situations. Participants predicted that situational constraints would restrain their own behavior more than it would the behavior of others, even in situations where everyone faced identical constraints. When anticipating the effects of deadlines on outcomes of negotiations, participants predicted that deadlines would hinder their performance more than it would hinder the performance of others. The results shed light on the psychological processes by which people predict the outcomes of and select strategies in strategic social interaction. They extend prior findings, such as people believing themselves to be below average on difficult tasks, to highly interdependent situations. Furthermore, the article shows both how focusing can account for these effects and also how perspective taking can reduce their biasing influence.
Group Identification and Outgroup Attitudes in Four South African Ethnic Groups: A Multidimensional Approach
Authors: Duckitt John , Callaghan Jane , Wagner Claire
Published: March 2005

Although Sumner’s ethnocentrism hypothesis, which expects stronger group identification to be associated with more negative outgroup attitudes, has been widely accepted, empirical findings have been inconsistent. This research investigates the relationship of four dimensions of ethnocultural group identification previously proposed by Phinney, that is, salience, evaluation, attachment, and involvement, with attitudes to ethnic outgroups in four South African ethnocultural groups (Africans, Afrikaans Whites, English Whites, Indians). The findings supported the factorial independence of the four identification dimensions and indicated that only one, ethnocultural evaluation (ingroup attitudes), was systematically related to outgroup attitudes, but the association could be positive, negative, or zero. Both functionalist and similarity-dissimilarity approaches to intergroup relations seemed to provide plausible explanations for the pattern of relationships obtained between ingroup and outgroup attitudes.