bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECT OF REPETITION RATES OF LASER PULSES ON MICROSTRUCTURE AND OPTICAL PROPERTIES OF DIAMOND-LIKE CARBON FILMS
Authors: DING X. L. , LI Q. S. , KONG X. H.
Published: December 2009

Hydrogen-free diamond-like carbon (DLC) thin films were prepared at different repetition rates of laser pulses by pulsed laser ablation of graphite target at room temperature. The microstructure of the thin films was characterized by Raman spectroscopy. Raman measurements showed that sp3 bonded carbon fraction is reduced with increase of repetition rates of laser pulses from 5 to 20 Hz. Optical properties, namely photoluminescence (PL), optical absorption, extinction coefficient (k), and refractive index (n), were measured by fluorescence spectrophotometer, scanning spectrophotometer, and spectroscopic ellipsometer. By changing the repetition rates of laser pulses from 5 to 20 Hz, the PL and optical absorption were gradually increased, while the deposition rate and optical band gap of the films decreased strictly with the increase of repetition rate. The extinction coefficient (k) and refractive index (n) were found to be in the range of 0.468–0.938 and 1.92–2.27, respectively. These results indicate that repetition rate of laser pulses has a strong influence on the microstructure and optical properties of the films. Based on the experimental results, a possible causation about the effect of repetition rate on PL was proposed.
PHASE SYNCHRONIZATION OF LINEARLY AND NONLINEARLY COUPLED OSCILLATORS WITH INTERNAL RESONANCE
Authors: LIU YONG
Published: December 2009

Phase synchronization between linearly and nonlinearly coupled systems with internal resonance is investigated in this paper. By introducing the conception of phase for a chaotic motion, it demonstrates that the detuning parameter σ between the two natural frequencies ω1and ω2affects phase dynamics, and with the increase in the linear coupling strength, the effect of phase synchronization between two sub-systems was enhanced, while increased firstly, and then decayed as nonlinear coupling strength increases. Further investigation reveals that the transition of phase states between the two oscillators are related to the critical changes of the Lyapunov exponents, which can also be explained by the diffuse clouds.
CHARACTERIZATION OF CHEMICALLY-DEPOSITED SILVER SULFIDE THIN FILMS
Authors: MOLLA M. Z. , CHOWDHURY M. R. I. , MUSTAFA G. , HUSSAIN S. , HOSSAIN K. S. , RAHMAN S. N. , KHATUN N. , AHMED N. A. , FARHAD S. F. U. , MURATA K. , TAMBO T. , ISLAM A. B. M. O.
Published: December 2009

Ag 2 S thin films have been deposited onto fluorinated tin oxide (FTO)-coated conducting glass substrates using chemical bath deposition (CBD) method. Photoelectrochemical (PEC) cell, optical properties, surface morphology, structural properties, compositional analysis and electrical properties of Ag 2 S thin films have been investigated. The PEC measurements indicate that the deposited Ag 2 S layers are n-type in electrical conduction. The transmittance of deposited layer is obtained to be about 13–87%. The absorbance of the films is found to decrease with increasing wavelength. The band gap of the Ag 2 S thin film is estimated to be 1.8 eV. It is observed from scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements that the substrates are well-covered with the deposited Ag 2 S layers without cracks and pinholes. The grain size of Ag 2 S thin films is estimated from SEM measurements to be in the range 100–210 nm. The mean roughness of Ag 2 S films is found from AFM measurements to be in the range 7.20–15 nm. X-ray diffraction shows that the films are well-crystallized and the deposited layers are mainly consisting of Ag 2 S phase with (-103) preferential plane. EDX analysis shows that a nearly stoichiometric composition of Ag 2 S is obtained. The resistivity is estimated to be in the range 3.5–7.0 Ω-cm.
SPINOR TWO-POINT FUNCTIONS AND PEIERLS BRACKET IN DE SITTER SPACE
Authors: ESPOSITO GIAMPIERO , ROYCHOWDHURY RAJU
Published: December 2009

This paper studies spinor two-point functions for spin-1/2 and spin-3/2 fields in maximally symmetric spaces such as de Sitter (dS) space–time, by using intrinsic geometric objects. The Feynman, positive- and negative-frequency Green functions are then obtained for these cases, from which we eventually display the supercommutator and the Peierls bracket under such a setting in two-component-spinor language.
ν-SPHERES, ν-DEGREES AND ν-ALGEBRAS
Authors: VARSAIE S.
Published: December 2009

A novel supergeometric generalization of common n-sphere, called ν-sphere, is introduced. It is shown that a canonical volume form exists on a ν-sphere. Then a concept of degree is developed for the maps between them. Finally, a semigroup action on ν-spheres is discussed.
NON-EXISTENCE OF PARA-KAHLER–NORDEN WARPED METRICS
Authors: SALIMOV A. A.
Published: December 2009

In this paper, we show that para-Kahler–Norden (or paraholomorphic) metrics do not exist on warped manifolds.
FRACTIONAL EQUATIONS OF THE RIGID BODY ON THE PSEUDO-ORTHOGONAL GROUP SO(2,1)
Authors: IVAN MIHAI , IVAN GHEORGHE , OPRIŞ DUMITRU
Published: December 2009

The main purpose of this paper is to investigate the fractional differential systems associated to dynamics of the rigid body on the Lie group SO(2,1) in terms of fractional Caputo derivatives.
QCM sensors for aqueous phenols based on active layers constituted by tetrapyrrolic macrocycle Langmuir films
Authors: Giancane Gabriele , Guascito Maria Rachele , Malitesta Cosimino , Mazzotta Elisabetta , Picca Rosaria Anna , Valli Ludovico
Published: December 2009

Three different metalated tetrapyrrolic macrocycles have been transferred by Langmuir-Blodgett technique directly onto piezoelectric quartz crystal covered with gold electrodes of a commercial quartz crystal microbalance instrument in order to perform a flow injection analysis. All floating films at the air-water interface have been analyzed by registration of Langmuir curves and by UV-vis reflection spectroscopy and brewster angle microscopy. The sensing performances of the modified gold electrodes were investigated by monitoring the frequency variation induced by the presence of several toxic phenols. The explored concentrations ranged around 10-3 M and the corresponding frequency variations ranged between 10 and 200 Hz. All responses observed were fast, reproducible and reversible; moreover, the active layers are stable over long periods of utilization. The observation that interferences from fulvic acid are absolutely negligible is also noteworthy. The responses are not selective for each singular phenol derivative; notwithstanding this, to the best of our knowledge, this contribution represents one of the first examples of sensing layers for the monitoring of the total content of phenols.
Tetrapyrrolic compounds as hosts for binding of halides and alkali metal cations
Authors: Kruk Mikalai M. , Starukhin Aleksander S. , Mamardashvili Nugzar Zh. , Mamardashvili Galina M. , Ivanova Yulia B. , Maltseva Olga V.
Published: December 2009

In this paper the binding of halides and alkali metal cations with porphyrin hosts is reported. The halide ions are complexed with diprotonated porphyrin macrocycle with high affinity and stable complexes of 1:1 and 1:2 structures with halide ions are formed. Strong (up to 300 times) quenching of the porphyrin fluorescence has been found upon the titration of porphyrin solutions with iodide ions. It was established that both static quenching upon formation of the non-fluorescent complex and dynamic diffusion-controlled quenching took place. It is shown that the halide ions binding isotherms can be linearized with double-logarithmic plots. The alkali metal cations are trapped with mono-meso-arylporphyrins containing a conformationally mobile complexing polyether fragment on the benzene ring with a terminal pyridine ring. The alkali metal cation binding constant depends on the polyether chain length. The five-membered (n = 5) polyether chain provides very high binding selectivity for potassium over lithium or sodium. The potassium complexation constants 3.6 × 105and 7.2 × 104M-1have been obtained for Zn2+complex and diprotonated porphyrin, respectively. For signaling of the alkali cation complexation, it is proposed to use the binding between the terminal pyridine ring with either the Lewis acidic site (chelated Zn2+ion) or the diprotonated macrocycle core ( H4P2+) acting as salt bridging site.
New insights into sensors based on radical bisphthalocyanines
Authors: Rodriguez-Méndez María Luz , Gay Mónica , de Saja J. Antonio
Published: December 2009

The unique semiconducting, optical and electrochemical properties of radical lanthanide bisphthalocyanines make them ideal materials for sensing applications. A variety of chemical sensors have been developed using rare-earth bisphthalocyanine thin films. In this paper, the characteristics of sensors based on bisphthalocyanines are reviewed. The advantages of these sensors with respect to sensors developed using other metallophthalocyanines are discussed. Resistive sensors based on bisphthalocyanines change their conductivity when exposed to a variety of pollutant gases and volatile organic compounds. Because bisphthalocyanines are intrinsic semiconductors, the conductivity of their thin films is higher than the conductivity of metallophthalocyanine thin films. This facilitates the electrical measurements and enhances the sensitivity of the sensors. Optical sensors have also been developed based on the rich optical properties shown by bisphthalocyanines. Films characterized by a bright green color change to red or to blue upon oxidation or reduction. The changes also affect the charge-transfer band associated to the free radical that bisphthalocyanines show in the near infrared region. This band coincides with telecommunication wavelengths, making possible the fabrication of fiber optic sensors where a phthalocyanine film is deposited at one of the ends of the fiber. Electrochemical sensors have been developed taking advantage of the unique electrochemical behavior associated to the one-electron oxidation and one-electron reduction of the phthalocyanine ring. These reversible processes are extremely sensitive to the nature of the electrolytic solution. This has made possible the development of voltammetric sensors able to produce particular signals when immersed in different liquids. In the last part of the paper, the fundamentals and performance characteristics of electronic noses and electronic tongues based on bisphthalocyanines are described. Such devices have been successfully exploited in quality control, classification, freshness evaluation and authenticity assessment of a variety of food, mainly wines and olive oils.
STRAIN DECONCENTRATION IN THIN FILMS PATTERNED WITH CIRCULAR HOLES
Authors: TUCKER MATTHEW B. , LI TENG
Published: December 2009

It is well known that a circular hole in a blanket thin film causes strain concentration near the hole edge when the thin film is under tension. The increased strain level can be as high as three times of the applied tension. Interestingly, we show that, by suitably patterning an array of circular holes in a thin film, the resulting strain in the patterned film can be decreased to only a fraction of the applied tension, even at the hole edges. The strain deconcentration in the film originates from the following deformation mechanism: while initially planar, the film patterned with circular holes elongates by deflecting out of plane, so that a large tension induces only small strains. Using finite element simulations, we investigate the effects of geometric parameters (i.e., hole size, spacing, and pattern) and loading direction on the resulting strain in patterned thin films under tension. The large deformability of the patterned film is independent of materials and length scale, and thus sheds light on a potential architecture concept for flexible electronics.
A FINITELY PRESENTED GROUP WITH ALMOST SOLVABLE CONJUGACY PROBLEM
Authors: Kalorkoti K.
Published: December 2009

The algorithmic unsolvability of the conjugacy problem for finitely presented groups was demonstrated by Novikov in the early 1950s. Various simplifications and alternative proofs were found by later researchers and further questions raised. Recent work by Borovik, Myasnikov and Remeslennikov has considered the question of what proportion of the number of elements of a group (obtained by standard constructions) falls into the realm of unsolvability. In this paper we provide a straightforward construction, as a Britton tower, of a finitely presented group with solvable word problem but unsolvable conjugacy problem of any r.e. (recursively enumerable) Turing degree a. The question of whether two elements are conjugate is bounded truth-table reducible to the question of whether the elements are both conjugate to a single generator of the group. We also define computable normal forms, based on the method of Bokut', that are suitable for the conjugacy problem. We consider (ordered) pairs of normal words U, V for the conjugacy problem whose lengths add to l and show that the proportion of such pairs for which conjugacy is undecidable (in the case a ≠ 0) is strictly less than l2/(2λ - 1)l where λ > 4.

The construction is based on modular machines, introduced by Aanderaa and Cohen. For the purposes of this construction it was helpful to extend the notion of configuration to include pairs of m-adic integers. The notion of computation step was also extended and is referred to as s-fold computation where s ∈ ℤ (the usual notion coresponds to s = 1). If gcd (m, s) = 1 then determinism is preserved, i.e., if the modular machine is deterministic then it remains so under the extended notion. Furthermore there is a simple correspondence between s-fold and standard computation in this case. Otherwise computation is non-deterministic and there does not seem to be any straightforward correspondence between s-fold and standard computation.
GREEN ♯-RELATIONS AND NORMAL ${\cal H}^\sharp$-CRYPTOGROUPS
Authors: Kong Xiang-zhi , Shum K. P.
Published: December 2009

In this paper, a new set of generalized Green's relations on a semigroup S, namely the set of Green ♯-relations, are introduced. By using these new Green ♯-relations, we prove that an [Formula: see text]-abundant semigroup is a normal [Formula: see text]-cryptogroup if and only if it is a strong semilattice of completely [Formula: see text]-simple cryptogroups. Our theorem simplifies a construction theorem of normal [Formula: see text]-abundant cryptographs previously described by the authors. Some properties of the good homomorphisms between the normal [Formula: see text]-cryptogroups are also investigated.
ON THE COMPUTATIONAL COMPLEXITY OF THE ARNOLD COMPLEXITY OF BINARY WORDS
Authors: Merekin Yu. V.
Published: December 2009

For an arbitrary binary word ω of Arnold complexity A(ω) we prove that the number of steps in computing A(ω) can be lowered from A(ω) to ν(A(ω)) where ν(A(ω)) is the number of occurrences of the digit 1 in A(ω). For a class of words we obtain an explicit algorithm for computing A(ω). We illustrate the efficacy of our construction by determining the Arnold complexity of the Thue–Morse sequence.
ATP consumption by sarcoplasmic reticulum Ca2+ pumps accounts for 50% of resting metabolic rate in mouse fast and slow twitch skeletal muscle
Authors: Norris Sarah Michelle , Bombardier Eric , Smith Ian Curtis , Vigna Chris , Tupling Allan Russell
Published: December 2009

In this study, we aimed to directly quantify the relative contribution of Ca2+ cycling to resting metabolic rate in mouse fast-twitch (extensor digitorum longus, EDL) and slow-twitch (soleus) skeletal muscle. Resting oxygen consumption of isolated muscles (V̇o2, μl·g wet wt−1·s−1) measured polarographically at 30°C was ∼25% higher in soleus (0.61 ± .03) than in EDL (0.46 ± .03). To quantify the specific contribution of Ca2+ cycling to resting metabolic rate, cyclopiazonic acid (CPA), a highly specific inhibitor of sarco(endo)plasmic reticulum Ca2+ ATPases (SERCAs), was added to the bath at different concentrations (1, 5, 10, and 15 μM). There was a concentration-dependent effect of CPA on V̇o2, with increasing CPA concentrations up to 10 μM resulting in progressively greater reductions in muscle V̇o2. There were no differences between 10 and 15 μM CPA, indicating that 10 μM CPA induces maximal inhibition of SERCAs in isolated muscle preparations. Relative reduction in muscle V̇o2 in response to CPA was nearly identical in EDL (1 μM, 10.6 ± 3.0%; 5 μM, 33.2 ± 3.4%; 10 μM, 49.2 ± 2.9%; 15 μM, 50.9 ± 2.1%) and soleus (1 μM, 11.2 ± 1.5%; 5 μM, 37.7 ± 2.4%; 10 μM, 50.0 ± 1.3%; 15 μM, 49.9 ± 1.6%). The results indicate that ATP consumption by SERCAs is responsible for ∼50% of resting metabolic rate in both mouse fast- and slow-twitch muscles at 30°C. Thus SERCA pumps in skeletal muscle could represent an important control point for energy balance regulation and a potential target for metabolic alterations to oppose obesity.
Extracellular glutathione peroxidase (Gpx3) binds specifically to basement membranes of mouse renal cortex tubule cells
Authors: Olson Gary E. , Whitin John C. , Hill Kristina E. , Winfrey Virginia P. , Motley Amy K. , Austin Lori M. , Deal Jacqualyn , Cohen Harvey J. , Burk Raymond F.
Published: December 2009

Glutathione peroxidase-3 (Gpx3), also known as plasma or extracellular glutathione peroxidase, is a selenoprotein secreted primarily by kidney proximal convoluted tubule cells. In this study Gpx3−/−mice have been produced and immunocytochemical techniques have been developed to investigate Gpx3 metabolism. Gpx3−/−mice maintained the same whole-body content and urinary excretion of selenium as did Gpx3+/+mice. They tolerated selenium deficiency without observable ill effects. The simultaneous knockout of Gpx3 and selenoprotein P revealed that these two selenoproteins account for >97% of plasma selenium. Immunocytochemistry experiments demonstrated that Gpx3 binds selectively, both in vivo and in vitro, to basement membranes of renal cortical proximal and distal convoluted tubules. Based on calculations using selenium content, the kidney pool of Gpx3 is over twice as large as the plasma pool. These data indicate that Gpx3 does not serve in the regulation of selenium metabolism. The specific binding of a large pool of Gpx3 to basement membranes in the kidney cortex strongly suggests a need for glutathione peroxidase activity in the cortical peritubular space.
Effect of Dopaminergic Medications on the Time Course of Explicit Motor Sequence Learning in Parkinson's Disease
Authors: Kwak Youngbin , Müller Martijn L. T. M. , Bohnen Nicolaas I. , Dayalu Praveen , Seidler Rachael D.
Published: December 2009

The capacity to learn new motor sequences is fundamental to adaptive motor behavior. The early phase of motor sequence learning relies on the ventral and anterior striatal circuitry, whereas the late phase relies on the dorsal and posterior striatal circuitry. Early Parkinson's disease (PD) is mainly characterized by dopaminergic denervation of the dorsal and posterior striatum while sparing anterior and ventral regions. Dopaminergic medication improves dorsal and posterior striatum function by compensating for the loss of dopamine. However, previous work has shown that dopaminergic medication interferes with the ventral and anterior striatum function by overdosing this relatively intact structure in early-state PD. Here we test whether these effects are also observed over the time course of motor sequence learning. Fourteen PD patients ON and OFF dopaminergic medications and 11 healthy age-matched control participants performed an explicit motor sequence learning task. When sequence learning was compared across different learning phases in patients ON and OFF medication, a significant impairment associated with medication was observed in the early relative to later phases of learning. The rate of learning in the early phase measured trial by trial in patients ON medication was significantly slower than that in controls and when patients were OFF medication. No significant impairment was found in the later learning phases. These results demonstrate that dopaminergic medications may selectively impair early-phase motor sequence learning. These results extend and generalize the dopamine overdose effects previously reported for (antero)ventral striatum-mediated cognitive tasks to motor sequence learning.
Changes in the Response Rate and Response Variability of Area V4 Neurons During the Preparation of Saccadic Eye Movements
Authors: Steinmetz Nicholas A. , Moore Tirin
Published: December 2009

The visually driven responses of macaque area V4 neurons are modulated during the preparation of saccadic eye movements, but the relationship between presaccadic modulation in area V4 and saccade preparation is poorly understood. Recent neurophysiological studies suggest that the variability across trials of spiking responses provides a more reliable signature of motor preparation than mean firing rate across trials. We compared the dynamics of the response rate and the variability in the rate across trials for area V4 neurons during the preparation of visually guided saccades. As in previous reports, we found that the mean firing rate of V4 neurons was enhanced when saccades were prepared to stimuli within a neuron's receptive field (RF) in comparison with saccades to a non-RF location. Further, we found robust decreases in response variability prior to saccades and found that these decreases predicted saccadic reaction times for saccades both to RF and non-RF stimuli. Importantly, response variability predicted reaction time whether or not there were any accompanying changes in mean firing rate. In addition to predicting saccade direction, the mean firing rate could also predict reaction time, but only for saccades directed to the RF stimuli. These results demonstrate that response variability of area V4 neurons, like mean response rate, provides a signature of saccade preparation. However, the two signatures reflect complementary aspects of that preparation.
Predictive Activity in Macaque Frontal Eye Field Neurons During Natural Scene Searching
Authors: Phillips Adam N. , Segraves Mark A.
Published: December 2009

Generating sequences of multiple saccadic eye movements allows us to search our environment quickly and efficiently. Although the frontal eye field cortex (FEF) has been linked to target selection and making saccades, little is known about its role in the control and performance of the sequences of saccades made during self-guided visual search. We recorded from FEF cells while monkeys searched for a target embedded in natural scenes and examined the degree to which cells with visual and visuo-movement activity showed evidence of target selection for future saccades. We found that for about half of these cells, activity during the fixation period between saccades predicted the next saccade in a sequence at an early time that precluded selection based on current visual input to a cell's response field. In addition to predicting the next saccade, activity during the fixation prior to two successive saccades also predicted the direction and goal of the second saccade in the sequence. We refer to this as advanced predictive activity. Unlike activity indicating the upcoming saccade, advanced predictive activity occurred later in the fixation period, mirroring the order of the saccade sequence itself. The remaining cells without advanced predictive activity did not predict future saccades but reintroduced the signal for the upcoming saccade at an intermediate time in the fixation period. Together these findings suggest that during natural visual search the timing of FEF cell activity is consistent with a role in specifying targets for one or more future saccades in a search sequence.
Heterotopic Quadruplet Pregnancy: Conservative Management with Ultrasonographically-Guided KCl Injection of Cornual Pregnancy and Laparoscopic Operation of Tubal Pregnancy
Authors: Park Hea-Ree , Moon Myoung-Jin , Ahn Eun-Hee , Baek Min-Jung , Choi Dong Hee
Published: December 2009

Objective: To discuss a case of heterotopic cornual and tubal pregnancy managed with transvaginal potassium chloride (KCl) injection of cornual pregnancy and laparoscopic operation of tubal pregnancy. Methods: The subject was a 30-year-old woman with twin pregnancy with a left cornual and a tubal pregnancy. The heterotopic cornual pregnancy was treated with ultrasonographically-guided transvaginal injection of KCl into the thorax of ectopic fetus, and the tubal pregnancy was treated with laparoscopic left salpingectomy. Results: The woman was discharged on the 6th postoperative day. After complete ablation of the cornual and tubal pregnancy, the subject had no complications or side effects for the duration of her pregnancy up to the 37th week. Elective cesarean section was performed at 37 weeks and allowed the birth of 2 boys weighing 2,500 and 2,000 g and of normal development. Conclusions: A minimally invasive approach should be considered in a hemodynamically stable patient to treat a first-trimester heterotopic pregnancy to maintain the intrauterine pregnancy with a satisfactory outcome.
Amniotic Fluid Index in Low-Risk, Post-Dates Pregnancies
Authors: Griffin Melanie , Attilakos George , Greenwood Rosemary , Denbow Mark
Published: December 2009

Objective: To determine normal values for amniotic fluid index (AFI) in uncomplicated post-dates singleton pregnancies and compare it to current reference ranges. Population: Four hundred and forty-eight women with singleton, uncomplicated pregnancies, presenting for post-dates assessment (gestation 40+0 to 42+0 weeks) between January 1, 2004 and June 30, 2005. Methods: Ultrasound assessment of liquor to calculate the AFI. Results: The mean and standard deviation for AFI in the sample was 9.86 (SD 3.4), which is significantly different to the mean of the currently used reference range (mean 11.6, SD 3.9, p < 0.0001). The 5th percentile in this population was 4.6 cm. Conclusions: This study has demonstrated lower mean and 5th percentile values for AFI in post-dates pregnancies than current reference ranges. It has the largest published UK study population, and can therefore be used as a reference range in similar populations, which is likely to reduce unnecessary obstetric interventions.
Potential Errors with Rapid Analysis Techniques: Partial Duplication 21q Resulting from a Paternal Paracentric Insertion Uncovered in Chorionic Villus Sampling by Fluorescence in situ Hybridization
Authors: Ehrhardt N. , Kujat A. , Faber R. , Horn L.-C. , Froster U.G.
Published: December 2009

We report on partial duplication 21q resulting from a paternal insertion identified during prenatal diagnosis. While performing interphase fluorescence in situ hybridization (I-FISH), we were able to identify 3 signals of the LSI 21 Spectrum Orange probe with chorionic villus sampling. Using standard cytogenetic analysis, I-FISH and GTG banding, structural aberrations in 21q in the parents and in the fetus could not be reliably determined. Applying metaphase fluorescence in situ hybridization (M-FISH), we identified a recombinant chromosome 21 carrying an interstitial duplication of the Down syndrome critical region inherited from the father. Both data from our analysis and published literature recommend the use of rapid testing methods such as I-FISH and standard cytogenetic analysis in prenatal diagnosis. It became obvious that I-FISH would not detect such a particular aberration. Thus, karyotyping, I-FISH and M-FISH should be performed in all Down syndrome cases.
Angiotensin Receptor Blocker Reduces Proteinuria Independently of Blood Pressure in Children Already Treated with Angiotensin-Converting Enzyme Inhibitors
Authors: Seeman Tomáš , Pohl Michael , Misselwitz Joachim , John Ulrike
Published: December 2009

Background/Aims: Dual blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) has higher antiproteinuric effects than single blockade in adults. In children, little is known on dual blockade of the renin-angiotensin system. The study investigates whether adding an ARB to proteinuric children already on ACEI reduces proteinuria. Methods: A total of 10 children (median age 13.3 years) with chronic kidney disease and persistent proteinuria despite maximal dose of ACEI were included. Losartan was given at an initial dose 0.8 mg/kg/day. Proteinuria, blood pressure (BP) and renal function (glomerular filtration rate) were measured. Results: Mean proteinuria decreased from 484 ± 290 mg/mmol creatinine to 223 ± 197 after 1–3 months of losartan treatment and remained stable at 234 ± 153, 224 ± 177 and 195 ± 133 after 3–6, 6–12 months and at the last follow-up check (median 1.9 years, p < 0.05 for all visits vs. before treatment). The median percentage decrease in proteinuria was 66, 56, 44 and 66% during the study periods. No significant change in BP, glomerular filtration rate or serum potassium was observed. One child complained of rash, which led to discontinuation of losartan. Conclusion: Adding an ARB to current ACEI treatment can further reduce proteinuria in children with chronic kidney disease without affecting BP.
Blood Volume- and Blood Temperature-Controlled Hemodialysis in Critically Ill Patients: A 6-Month, Case-Matched, Open-Label Study
Authors: du Cheyron Damien , Lucidarme Olivier , Terzi Nicolas , Charbonneau Pierre
Published: December 2009

Background/Aims: Online monitoring devices for intermittent hemodialysis have been developed to improve intradialytic cardiovascular stability in chronic dialysis patients. We propose to test blood volume and blood temperature biofeedback control systems in critically ill patients with acute kidney injury (AKI). Methods: Twenty patients were prospectively dialyzed with machines equipped with online monitoring new devices and compared with 42 historical controls. In addition to feasibility and safety appraisals, efficacy was assessed by the intradialytic hypotension rate. Results: During the study period, controlled temperature was assessed by a mean Δmax body temperature of –0.3 ± 0.2°C, and all but 7% of dialysis sessions achieved relative blood volume-guided ultrafiltration profiling without increased dialysis-related complications. This was associated with decreased intradialytic hypotension rate. Conclusion: The combination of active controlled body temperature and profiled ultrafiltration by online monitoring systems is feasible and safe in critically ill AKI patients, and suggests possibilities for improvement in intradialytic hemodynamic stability.
Triglyceride-Rich Lipoproteins and Plasma Lipid Transport
Authors: Havel Richard J.
Published: December 2009

This memoir provides a history of the triglyceride-rich lipoproteins of blood plasma over the last half-century. As precursors of low-density lipoproteins and in their own right, triglyceride-rich lipoproteins are essential to the formation of atherosclerotic plaques and to consequent ischemic vascular disease. The author recounts research at the National Heart Institute during 1953 to 1956 and continuing thereafter at the University of California San Francisco. Emphasis is placed on key insights arising from investigations of human disease, the interplay of fatty acid and triglyceride-transport involving the liver, small intestine, adipose tissue and muscle, and the role of the liver in the synthesis and catabolism of atherogenic lipoproteins.
Lipolysis Needed for Chylomicron Uptake?
Authors: Parthasarathy Sampath
Published: December 2009

Despite clinical evidence that postprandial lipemia and chylomicrons could contribute to atherosclerosis, direct evidence is lacking. The study by Weinstein et al

1

provides evidence to suggest that intact chylomicrons might be atherogenic by using genetically altered mice lacking
Gpihbp1
protein, which may play a major role in the lipolysis of triglyceride-rich lipoproteins. However, the study does not rule out a contribution by remnants or limited lipolysis by other potential enzymes or pathways. It might be intriguing to determine the contribution of cholesterol derivatives in the chylomicrons to the lesions and the nature of the lesions.
Observed Long-Term Trends for Agroclimatic Conditions in Canada
Authors: Qian Budong , Zhang Xuebin , Chen Kai , Feng Yang , O’Brien Ted
Published: December 2009

A set of agroclimatic indices representing Canadian climatic conditions for field crop production are analyzed for long-term trends during 1895–2007. The indices are categorized for three crop types: cool season, warm season, and overwintering. Results indicate a significant lengthening of the growing season due to a significantly earlier start and a significantly later end of the growing season. Significant positive trends are also observed for effective growing degree-days and crop heat units at most locations across the country. The occurrence of extremely low temperatures has become less frequent during the nongrowing season, implying a more favorable climate for overwinter survival. In addition, the total numbers of cool days, frost days, and killing-frost days within a growing season have a decreasing trend. This means that crops may also be less vulnerable to cold stress and injury during the growing season. Extreme daily precipitation amounts and 10-day precipitation totals during the growing season have been increasing. Significant trends associated with increased availability of water during the growing season are identified by the standardized precipitation index and seasonal water deficits. The benefit of the increased precipitation may have been offset by an upward trend in evaporative demand; however, this would depend on the amount of growth and productivity resulting from increased actual evapotranspiration.
Structure and Mechanisms of the Southern Hemisphere Summertime Subtropical Anticyclones
Authors: Miyasaka Takafumi , Nakamura Hisashi
Published: December 2009

The three-dimensional structure and dynamics of the climatological-mean summertime subtropical anticyclones in the Southern Hemisphere (SH) are investigated. As in the Northern Hemisphere (NH), each of the surface subtropical anticyclones over the South Pacific, South Atlantic, and South Indian Oceans is accompanied by a meridional vorticity dipole aloft, exhibiting barotropic and baroclinic structures in its poleward and equatorward portions, respectively, in a manner that is dynamically consistent with the observed midtropospheric subsidence. Their dynamics are also similar to their NH counterpart. It is demonstrated through the numerical experiments presented here that each of the SH surface anticyclones observed over the relatively cool eastern oceans can be reproduced as a response to a local near-surface cooling–heating couplet. The cooling is mainly due to radiative cooling associated with low-level maritime clouds, and the heating to the east is due to sensible heat flux over the dry, heated continental surface. The low-level clouds act to maintain the coolness of the underlying ocean surface, which is also maintained by the alongshore surface southerlies. As in the NH, the presence of a local atmosphere–ocean–land feedback loop is thus suggested, in which the summertime subtropical anticyclones and continental cyclones to their east are involved. Both the model experiments conducted here and the diagnosed upward flux of Rossby wave activity suggest that, in addition to continental deep convective heating, the land–sea heating–cooling contrasts across the west coasts of the three continents can contribute to the formation of the summertime upper-level planetary wave pattern observed in the entire subtropical SH, characterized by the zonal wavenumber-3 component. Though rather subtle, there are some interhemispheric differences in the summertime subtropical anticyclones, including their smaller magnitudes in the SH and the stronger equatorward propagation of upper-level Rossby wave activity emanating from the SH surface anticyclones.
Changes in the Risk of Cool-Season Tornadoes over Southern Australia due to Model Projections of Anthropogenic Warming
Authors: Timbal B. , Kounkou R. , Mills G. A.
Published: December 2009

Anthropogenic climate change is likely to be felt most acutely through changes in the frequency of extreme meteorological events. However, quantifying the impact of climate change on these events is a challenge because the core of the climate change science relies on general circulation models to detail future climate projections, and many of these extreme events occur on small scales that are not resolved by climate models. This note describes an attempt to infer the impact of climate change on one particular type of extreme meteorological event—the cool-season tornadoes of southern Australia. The Australian Bureau of Meteorology predicts threat areas for cool-season tornadoes using fine-resolution numerical weather prediction model output to define areas where the buoyancy of a near-surface air parcel and the vertical wind shear each exceed specified thresholds. The diagnostic has been successfully adapted to coarser-resolution climate models and applied to simulations of the current climate, as well as future projections of the climate over southern Australia. Simulations of the late twentieth century are used to validate the models’ ability to reproduce the climatology of the risk of cool-season tornado formation by comparing these with similar computations based on historical reanalyses. Model biases are overcome by setting model specific thresholds to define the cool-season tornado risk. The diagnostic, applied to simulations of the twenty-first century, is then used to quantify the impact of the projected climate change on cool-season tornado risk. The sign of the response is consistent across all models: a decrease of the risk of formation during the twenty-first century is projected, driven by the thermodynamical response. The thermal response is modulated by the dynamical response, which varies between models. The projected decrease in tornadoes risk during the cool season is consistent with the projection of positive southern annular mode trends and the known influence of this mode of variability on interannual to intraseasonal time-scale variations in cool-season tornado occurrence.
Horizontal Stratification of Higher Education in Russia: Trends, Gender Differences, and Labor Market Outcomes
Authors: Gerber Theodore P. , Schaefer David R.
Published: December 2009

Using survey data collected in fall 2000, the authors analyzed four aspects of “horizontal” variation among Russian university students: field of specialization, cost (paid versus free), intensity (full- versus part-time study), and timing of study (Soviet versus post-Soviet era). For each type of variation, they examined trends over time, gender differences, and effects on earnings and employment opportunities. In Russia, as elsewhere, horizontal differentiation of higher education has stratifying consequences. Unlike in many countries, gender differences along horizontal dimensions have not narrowed in Russia; in fact, the gender gap in part-time study has widened. But the introduction of market forces in higher education and the economy has shaped both male and female distributions across specialty, cost, and intensity. The labor market advantages accruing to a university degree differ across these horizontal dimensions and by the timing of the degree. Some of the patterns observed in Russia resemble those in the United States, while others are distinctive.
Social Capital and the Diffusion of Innovations Within Organizations: The Case of Computer Technology in Schools
Authors: Frank Kenneth A. , Zhao Yong , Borman Kathryn
Published: December 2009

Although the educational community has learned much about better educational practices, less is known about processes for implementing new practices. The standard model of diffusion suggests that people change perceptions about the value of an innovation through communication, and these perceptions then drive implementation. But implementation can be affected by more instrumental forces. In particular, members of a school share the common fate of the organization and affiliate with the common social system of the organization. Thus, they are more able to gain access to each others' expertise informally and are more likely to respond to social pressure to implement an innovation, regardless of their own perceptions of the value of the innovation. This article characterizes informal access to expertise and responses to social pressure as manifestations of social capital. Using longitudinal and network data in a study of the implementation of computer technology in six schools, the authors found that the effects of perceived social pressure and access to expertise through help and talk were at least as important as the effects of traditional constructs. By implication, change agents should attend to local social capital processes that are related to the implementation of educational innovations or reforms.
State Formation of the Child Care Sector: Family Demand and Policy Action
Authors: Fuller Bruce , Loeb Susanna , Strath Annelie , Carrol Bidemi Abioseh
Published: December 2009

This article identifies the extent to which fiscal and regulatory action by state governments shapes the formation of sectors—in this case, including the local availability, organizational formalization, and quality of teachers in child care centers nationwide. These state-level effects are compared to the local effects of family demand and associated demographics of households. Although demand factors (e.g., maternal employment, income levels, and ethnic composition of communities) explain a greater share of the variance in the availability and formalization of child care centers, state governments have been effective in spurring organizational growth within low-income communities, advancing formalization and quality in particular. Communities with more civic organizations and churches per capita display a stronger capacity to expand and formalize child care centers. The formation of this sector appears to stem from pluralistic politics, resulting in variable state spending and regulatory actions, not simply from a deterministic advance of rationalized institutions.
Organizational Environments and the Emergence of Charter Schools in the United States
Authors: Renzulli Linda A.
Published: December 2009

There is a growing abundance of research on outcomes of charter schools for children, teachers, and communities, yet a paucity of research on why and how charter schools form in the first place. This article presents unique data on charter school applications to show how the early stages of school formation are embedded in, if not driven by, an organizational and institutional context. Three organizational theories—neoinstitutional, population ecology, and resource dependence—are used to explain the formation of charter schools. The results suggest that educational organizational environments are indeed key in the process of generating charter schools. Nonreligious private schools increase the submission of charter school applications, while the density of extant charter schools in local districts—or saturation, in general—decreases the submission of applications. Finally, local political environments and legislative support matter as well. Implications for understanding the formation of charter schools are discussed, as is the more general importance of understanding educational options as a function of organizational environments.
School Shootings as Organizational Deviance
Authors: Fox Cybelle , Harding David J.
Published: December 2009

This article argues that rampage school shootings in American public schools can be understood as instances of organizational deviance, which occurs when events created by or in organizations do not conform to an organization's goals or expectations and produce unanticipated and harmful outcomes. Drawing on data from qualitative case studies of two schools that experienced shootings, the authors show how the organizational structure, environment, and culture of these schools led to the loss of information about socially or emotionally troubled students, information that might otherwise have led to some form of intervention or help for these students. Implications for educational policy and practice are discussed.
Maternal Cohabitation and Educational Success
Authors: Raley R. Kelly , Frisco Michelle L. , Wildsmith Elizabeth
Published: December 2009

Despite the dramatic increase in children's experiences in cohabiting families, little is known about how living in such families affects children's academic success. Extrapolating from two theoretical frameworks that have been commonly used to explain the association between parental divorce and educational outcomes, the authors constructed competing hypotheses about the effect of maternal cohabitation on educational expectations, achievement, and attainment. The analysis of data from the National Survey of Families and Households shows that children who lived with cohabiting mothers fared exceptionally poorly and sometimes were significantly worse off than were children who lived with divorced or remarried mothers. The authors conclude that studies that have ignored cohabitation have probably overestimated the negative effects of divorce on educational outcomes. High levels of family instability that are associated with cohabitation may be one reason why children whose mothers cohabit do less well than do children with other types of family experiences.
The Natural Sciences in the University: Change and Variation over the 20th Century
Authors: Gabler Jay , Frank David John
Published: December 2009

The changing academic priorities of universities are often discussed but little investigated by social scientists: What accounts for the striking expansions and contractions in disciplinary fields over time? Focusing specifically on the natural sciences, this article articulates a global-institutional argument that holds that deep shifts in ontological conceptions of action and structure over the course of the 20th century fomented shifts in the teaching and research emphases of universities worldwide. Specifically, it hypothesizes that scientific fields that are premised on fixed categories and hierarchies of entities (for example, zoology) declined relative to fields that are premised on dynamic, horizontal networks of entities (for example, physics). In addition, it hypothesizes that as globally institutionalized reality shifted in favor of human, rather than divine, actorhood, fields that position their practitioners as active investigators in a dynamic universe gained ascendance over those that position practitioners as passive observers of a divinely ordered universe. Using data on worldwide faculty composition from 1915 to 1995, the authors found that these shifts indeed transpired—the fixed-categorical fields of astronomy, botany, and zoology declined precipitously, while the dynamic-network fields of geology, biology, chemistry, physics, and mathematics performed much more robustly.