bluuebunny/crossref_metadata_2025 huggingface dataset:
Accuracy of imaging parameters in the prediction of lethal pulmonary hypoplasia secondary to mid‐trimester prelabor rupture of fetal membranes: a systematic review and meta‐analysis
Authors: van Teeffelen A. S. P. , Van Der Heijden J. , Oei S. G. , Porath M. M. , Willekes C. , Opmeer B. , Mol B. W. J.
Published: July 2011

In women who have suffered mid‐trimester prelabor rupture of membranes (PPROM), prediction of pulmonary hypoplasia is important for optimal management. We performed a systematic review to assess the capacity of imaging parameters to predict pulmonary hypoplasia. We searched for published articles that reported on biometric parameters and allowed the construction of a 2 × 2 table, comparing at least one of these parameters with the occurrence of pulmonary hypoplasia. The selected studies were scored on methodological quality and we calculated sensitivity and specificity of the tests in the prediction of pulmonary hypoplasia and lethal pulmonary hypoplasia. Overall performance was assessed by summary receiver–operating characteristics (sROC) analyses that were performed with bivariate meta‐analysis. We detected 13 studies that reported on the prediction of lethal pulmonary hypoplasia. The quality of the included studies was poor to mediocre. The estimated sROC curves for the chest circumference/abdominal circumference ratio and other parameters showed limited accuracy in the prediction of pulmonary hypoplasia. In women with mid‐trimester PPROM, the available evidence indicates limited accuracy of biometric parameters in the prediction of pulmonary hypoplasia. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
Reproducibility of constituent time intervals of right and left fetal modified myocardial performance indices on pulsed Doppler echocardiography: a short report
Authors: Meriki N. , Izurieta A. , Welsh A.
Published: July 2011

Objective

To assess reproducibility of constituent time intervals measured by pulsed Doppler echocardiography for calculation of the right and left fetal myocardial performance indices (MPIs).

Methods

This was a prospective study of 30 normal singleton pregnancies (19–36 weeks). In each, five different time intervals were measured from the Doppler waveform and four repeated measures were taken for each time interval. Three were from the left heart: isovolumetric contraction time (ICT), isovolumetric relaxation time (IRT) and ejection time (ET); two were from the right heart: ‘a‐interval’ and ‘b‐interval’. The left and right modified MPIs (Mod‐MPIs) generated by these constituent time intervals were also evaluated. Two operators evaluated the reproducibility of all measures.

Results

There was generally good intra‐ and interobserver reproducibility for all time intervals and resultant Mod‐MPIs: ICT, range, 19–43 ms with intraclass correlation coefficient (ICC), 0.91 (95% CI, 0.85–0.95); ET, range, 160–184.8 ms with ICC, 0.90 (95% CI, 0.84–0.95); IRT, range, 35.8–48.5 ms with ICC, 0.67 (95% CI, 0.52–0.81); a‐interval, range 208–265 ms with ICC, 0.89 (95% CI, 0.82–0.94); b‐interval, range, 163.1–188.3 ms with ICC, 0.82 (95% CI, 0.71–0.90); left Mod‐MPI, range, 0.33–0.48 with ICC, 0.84 (95% CI, 0.74–0.91); right Mod‐MPI, range, 0.21–0.49 with ICC, 0.82 (95% CI, 0.71–0.90). The 95% limits of agreement showed no statistically significant difference in measurements between the two examiners for all time intervals.

Conclusion

This is the first study to evaluate the reproducibility of the component time intervals of both right and left fetal Mod‐MPIs in the second and third trimesters and supports the reproducibility of fetal functional cardiac assessment. The IRT is the main source of variation for the left Mod‐MPI so should be the focus of further investigation. Even using two separate pulsed‐wave Doppler gates and therefore separate cardiac cycles, the right Mod‐MPI is reproducible. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
Characterization of some ancient glass vessels fragments found in Xinjiang, China, using a portable energy dispersive XRF spectrometer
Authors: Liu Song , Li Qinghui , Gan Fuxi , Zhang Ping
Published: July 2011

In this article, a portable energy dispersive X‐ray fluorescence spectrometer having determination capability for elements of Na and Mg is applied to characterization of the 58 ancient glass vessels fragments found in Xinjiang, China, successfully. These ancient glass samples were found in different historical sites dated from the Han Dynasty (202 B.C.–220 A.D.) to early Yuan Dynasty (1271–1368 A.D.). The chemical composition difference between the original weathered and inner fresh surfaces is distinguished. Using Mg, Ca, Al and K as the diagnostic elements, the glass samples analyzed are mainly classified into three types through cluster analysis. Each type of glass seems to be produced under different recipes. The techniques used to make these glasses and their possible provenances are discussed briefly. The obtained results provide new useful information for further understanding of the exchange and trade networks related to early glasses found in Xinjiang, China. Copyright © 2011 John Wiley & Sons, Ltd.
A comparative study on determination of uranium and thorium in their mixed oxides by EDXRF using tube and radioisotope X‐ray sources
Authors: Misra N. L. , Kumar S. Sanjay , Dhara Sangita , Singh Ajit Kumar , Lodha G. S. , Aggarwal Suresh Kumar
Published: July 2011

Studies on the matrix effects of uranium and thorium on the determinations of each other in their mixed oxides using energy dispersive X‐ray fluorescence (EDXRF) spectrometry with tube and radioisotope excitations of U Lα and Th Lα are reported. An internal standard method for the determination of uranium and thorium in these mixed oxides is found suitable. Comparison of the analytical results of EDXRF determinations of uranium and thorium using tube and radioisotope excitation sources has been made. The analytical methodology involves preparation of mixed oxide calibration/sample mixtures of uranium and thorium oxides, mixing of internal standard yttrium in these mixtures, pelletizing the mixtures after thorough mixing and grinding using boric acid binder and measuring EDXRF spectra of the specimens thus prepared using Rh X‐ray tube as well as 109Cd radioisotope source. The samples were analyzed for uranium and thorium on the basis of the calibration plots obtained by plotting the intensity ratios of the analyte and internal standard characteristic X‐ray lines and their corresponding amount ratios. An average precision of 1.2% (1 s RSD) was observed for the determination of U and Th and the results deviated from the corresponding expected values by 3% on average. Due to the refractory nature of thorium oxide, comparatively more grinding time was required for thorium determinations. Copyright © 2011 John Wiley & Sons, Ltd.
Antibacterial and Superoxide Dismutase Activity as Well as DNA Interactions of Ciprofloxacin‐Based Ternary Copper(II) Phenanthroline Complexes
Authors: Patel Mohan N. , Dosi Promise A. , Bhatt Bhupesh S.
Published: July 2011

. Five neutral mixed‐ligand mononuclear square‐pyramidal copper(II) complexes of the type [Cu(cpf)(Ln)Cl] (cpf = ciprofloxacin and Ln = phenanthroline derivatives) (1–5) were synthesized and characterized. The complexes were screened for their antibacterial activity and bactericidal activity against two Gram(+ve) and three Gram(–ve) microorganisms and the results showed that all complexes studied are more potent than the quinolone standard drug ciprofloxacin. Absorption titration, viscosity, and thermal denaturation measurement studies revealed that each of these square‐pyramidal complexes moderately interacts with calf thymus DNA. The binding constants for mixed ligand complexes are in order of 1.5 × 104–3.0 × 104 M–1. Based on the data obtained in the DNA binding studies an intercalative mode of binding is suggested for these complexes. The nucleolytic cleavage activity of adducts and gyrase inhibition assay were studied on double stranded pUC19 DNA by gel electrophoresis experiments. From the SOD mimic study; the concentration of complexes ranging from 0.45 μM to 1.45 μM are enough to inhibit the reduction rate of NBT by 50 % (IC50) in NADH/PMS system.
The Crystal Structures of two Anhydrous Magnesium Hydroxychloride Phases from in situ Synchrotron Powder Diffraction Data
Authors: Dinnebier Robert E. , Halasz Ivan , Freyer Daniela , Hanson Jonathan C.
Published: July 2011

The crystal structures of two members of the solid solution series Mg(OH)xCly x+y = 2, Mg(OH)1.7Cl0.3 (P$\tilde {3}$m1, a = 3.169(2) Å, c = 5.530(12), V = 48.1(1) Å3 at T = 365 °C) and MgOHCl (R$\tilde {3}$m, a = 3.3877(4) Å, c = 17.534(4) Å, V = 174.27(6) Å3 at T = 625 °C) were determined from in situ synchrotron powder diffraction data at high temperature upon dehydration of 3Mg(OH)2·MgCl2·8H2O (F3) and 5Mg(OH)2·MgCl2·8H2O (F5) phases. The crystal structures of Mg(OH)1.7Cl0.3 (example of ss‐type‐OH) and MgOHCl (example of ss‐type‐Cl) can be related to the C19 (CdCl2) and C6 (CdI2) structure type, respectively, with the disordered chloride and hydroxide anions occupying the same crystallographic site in layers.
[Te8]2[Ta4O4Cl16]: A Two‐dimensional Tellurium Polycation obtained via Ionic Liquid‐Based Synthesis
Authors: Freudenmann Dominic , Feldmann Claus
Published: July 2011

By reaction of elemental tellurium, tellurium(IV) chloride, tantalum(V) chloride and tantalum(V) oxychloride in the ionic liquid [BMIM]Cl ([BMIM]Cl:1‐Butyl‐3‐methylimidazolium chloride),[Te8]2[Ta4O4Cl16] is obtained in the form of lucent black crystals. The title compound consists of infinite [Te–Te–(Te6)]n2+ chains (Te–Te: 264.9(1)–284.3(1) pm) and isolated [Ta4O4Cl16]4– anions. The [Te–Te–(Te6)]n2+ chains are interconnected to form a two‐dimensional tellurium network (Te–Te: 335.9 pm). Due to this interaction the [Te–Te–(Te6)]n2+ chains in [Te8]2[Ta4O4Cl16] show an arrangement that differs significantly from known polycationic [Te8]n2+ chains. The two‐dimensional tellurium network is finally separated by tetrameric, corner‐sharing oxidochloridotantalate anions [(TaO2/2Cl4/1)4]4– that are firstly observed. The composition of [Te8]2[Ta4O4Cl16] is confirmed by EDX analysis; its optical band gap is estimated to 1.1–1.2 eV via UV/Vis spectroscopy.
Synthesis, Crystal Structure, and Thermal Properties of the Energetic Coordination Compound [Co(DAT)2(H2O)4](HTNR)2·2H2O (DAT = 1,5‐diaminotetrazole)
Authors: Zhang Jianguo , Wei Lei , Cui Yan , Zhang Tonglai , Zhou Zunning , Yang Li
Published: July 2011

A new coordination complex, [Co(DAT)2(H2O)4](HTNR)2·2H2O [DAT = 1,5‐diaminotetrazole, HTNR = 2,4,6‐trinitroresorcinol (styphnic acid)], was obtained in high yield and characterized by elemental analysis and Fourier‐transform infrared (FT‐IR) spectroscopy. The molecular structure of [Co(DAT)2(H2O)4](HTNR)2·2H2O in the crystalline state is determined by X‐ray crystallography is as follows: monoclinic, C2/c, a = 19.216(3) Å, b = 5.4992(8) Å, c = 30.418(5) Å, β = 104.500(5), V = 3112.0(8) Å3, Z = 4, ρcalc. = 1.851 g·cm–3, R1 = 0.0271 and wR2 = (all data) 0.0674. The central cobalt(II) cation is coordinated by two nitrogen atoms of two DAT and four oxygen atoms of four H2O ligand molecules to form a six‐coordinate and slightly distorted octahedral structure. Extensive intermolecular hydrogen bonds link molecular units of [Co(DAT)2(H2O)4(HTNR)2·2H2O together to form a 3D net structure with pore canals. The thermal decomposition mechanism for the title compound was predicted based on DSC, TG‐DTG, and FT‐IR analyses and non‐kinetic parameters of the first exothermic process were estimated by applying the Kissinger, Starink, and Ozawa–Doyle methods.
The Effectiveness of Branded Mobile Phone Apps
Authors: Bellman Steven , Potter Robert F. , Treleaven-Hassard Shiree , Robinson Jennifer A. , Varan Duane
Published: July 2011

Mobile phone applications (“apps”) have generated substantial interest among marketers, primarily because of their high level of user engagement and the positive impact this presumably has on a user's attitude toward the sponsoring brand. This study utilized a pre-test/post-test experimental design to determine whether using popular mobile phone apps affects brand attitude and brand purchase intention. The results show that using these apps has a positive persuasive impact, increasing interest in the brand and also the brand's product category. The relevance of the product category makes no difference, but apps with an informational/user-centered style were more effective at shifting purchase intention, most likely because this style focuses attention on the user, and therefore encourages making personal connections with the brand. Experiential game-like apps were less successful, because they focus attention on the phone. These results suggest that understanding how to maximize the impact of mobile phone apps will be a key topic for future research.
Costs of care in a mild‐to‐moderate Alzheimer clinical trial sample: Key resources and their determinants
Authors: Gustavsson Anders , Cattelin Francoise , Jönsson Linus
Published: July 2011

Background

Costs of care are frequently included as secondary endpoint in Alzheimer clinical trials because payers demand evidence of the budgetary effects of novel therapies. Future clinical trial protocols can be optimized on the basis of the currently available data, including what are the key resources and how are they correlated to disease severity measures.

Methods

Primary patient‐level data from two 18 months clinical trials of a putative disease modifier in mild‐to‐moderate Alzheimer's disease (n = 2,744) were analyzed to identify key components of costs of care and their determinants in a clinical trial setting. Costs of care were assessed with the resource utilization in dementia Lite (RUD) instrument, which includes patient accommodation, informal care, community care, and hospitalizations. The contribution of each component to total costs of care and their correlation with one another and key disease severity measures (Alzheimer's Disease Assessment Scale–Cognitive Subscale, Mini‐Mental State Examination, Clinical Dementia Rating–Sum of Boxes, Alzheimer's Disease Cooperative Study–Activities of Daily Living Inventory, and Neuropsychiatric Inventory Questionnaire) was explored.

Results

Informal care constituted 82% to 86% of the total costs of care over the 18‐months trial and community care services and patient accommodation contributed 6% to 8% each. Informal care was positively correlated with hospitalizations but negatively to patient accommodation, indicating that these services are supplements. Informal care also had the strongest pair‐wise correlation with key disease severity measures, suggesting a higher chance of identifying a treatment effect on this component. ADL‐ability (Alzheimer's Disease Cooperative Study–Activities of Daily Living Inventory) was the strongest predictor of costs of care of all disease severity measures.

Conclusions

Informal care is the most important component of costs of care in a mild‐to‐moderate Alzheimer clinical trial sample, and it is primarily driven by the ADL‐ability of the patient. Investigators should focus on the assessment of this economic endpoint because a significant treatment effect on this resource is likely to also affect total costs of care.
Extended results of the Alzheimer's disease anti‐inflammatory prevention trial
Authors: Breitner John C. , Baker Laura D. , Montine Thomas J. , Meinert Curtis L. , Lyketsos Constantine G. , Ashe Karen H. , Brandt Jason , Craft Suzanne , Evans Denis E. , Green Robert C. , Ismail M. Saleem , Martin Barbara K. , Mullan Michael J. , Sabbagh Marwan , Tariot Pierre N.
Published: July 2011

Background

Epidemiologic evidence suggests that nonsteroidal anti‐inflammatory drugs (NSAIDs) delay onset of Alzheimer's dementia (AD), but randomized trials show no benefit from NSAIDs in patients with symptomatic AD. The Alzheimer's Disease Anti‐inflammatory Prevention Trial (ADAPT) randomized 2528 elderly persons to naproxen or celecoxib versus placebo for 2 years (standard deviation = 11 months) before treatments were terminated. During the treatment interval, 32 cases of AD revealed increased rates in both NSAID‐assigned groups.

Methods

We continued the double‐masked ADAPT protocol for 2 additional years to investigate incidence of AD (primary outcome). We then collected cerebrospinal fluid (CSF) from 117 volunteer participants to assess their ratio of CSF tau to Aβ1‐42.

Results

Including 40 new events observed during follow‐up of 2071 randomized individuals (92% of participants at treatment cessation), there were 72 AD cases. Overall, NSAID‐related harm was no longer evident, but secondary analyses showed that increased risk remained notable in the first 2.5 years of observations, especially in 54 persons enrolled with cognitive impairment––no dementia (CIND). These same analyses showed later reduction in AD incidence among asymptomatic enrollees who were given naproxen. CSF biomarker assays suggested that the latter result reflected reduced Alzheimer‐type neurodegeneration.

Conclusions

These data suggest a revision of the original ADAPT hypothesis that NSAIDs reduce AD risk, as follows: NSAIDs have an adverse effect in later stages of AD pathogenesis, whereas asymptomatic individuals treated with conventional NSAIDs such as naproxen experience reduced AD incidence, but only after 2 to 3 years. Thus, treatment effects differ at various stages of disease. This hypothesis is consistent with data from both trials and epidemiological studies.
A dynamical instability due to fluid–wall coupling lowers the transition Reynolds number in the flow through a flexible tube
Authors: Verma M. K. S. , Kumaran V.
Published: July 2011

A flow-induced instability in a tube with flexible walls is studied experimentally. Tubes of diameter 0.8 and 1.2 mm are cast in polydimethylsiloxane (PDMS) polymer gels, and the catalyst concentration in these gels is varied to obtain shear modulus in the range 17–550 kPa. A pressure drop between the inlet and outlet of the tube is used to drive fluid flow, and the friction factor $f$ is measured as a function of the Reynolds number $Re$. From these measurements, it is found that the laminar flow becomes unstable, and there is a transition to a more complicated flow profile, for Reynolds numbers as low as 500 for the softest gels used here. The nature of the $f$–$Re$ curves is also qualitatively different from that in the flow past rigid tubes; in contrast to the discontinuous increase in the friction factor at transition in a rigid tube, it is found that there is a continuous increase in the friction factor from the laminar value of $16/ Re$ in a flexible tube. The onset of transition is also detected by a dye-stream method, where a stream of dye is injected into the centre of the tube. It is found that there is a continuous increase of the amplitude of perturbations at the onset of transition in a flexible tube, in contrast to the abrupt disruption of the dye stream at transition in a rigid tube. There are oscillations in the wall of the tube at the onset of transition, which is detected from the laser scattering off the walls of the tube. This indicates that the coupling between the fluid stresses and the elastic stresses in the wall results in an instability of the laminar flow.
Protective effects of fractional extracts fromPanellus serotinuson non-alcoholic fatty liver disease in obese, diabeticdb/dbmice
Authors: Inafuku Masashi , Nagao Koji , Nomura Saori , Shirouchi Bungo , Inoue Nao , Nagamori Naoki , Nakayama Hideyuki , Toda Takayoshi , Yanagita Teruyoshi
Published: July 2011

Non-alcoholic fatty liver disease (NAFLD) is emerging as the most common liver disease in industrialised countries. Various mushrooms have been used in Eastern folk medicine for the treatment of lifestyle diseases. We previously found that the dietary intake of powdered wholePanellus serotinus(Mukitake) alleviates NAFLD in obese, diabeticdb/dbmice. In the present study, we investigated the influence of Mukitake fractional extracts on the development of NAFLD indb/dbmice. A significant reduction in the hepatic TAG content, macrovesicular hepatocytes and activities of key enzymes forde novosynthesis of the fatty acid was observed in both the water-soluble Mukitake extract (WE) diet and the ethanol-soluble Mukitake extract (EE) diet groups compared with the control diet group of thedb/dbmice. The serum level of monocyte chemoattractant protein-1 (MCP-1), which is known to exacerbate insulin resistance, was significantly decreased in the WE group. On the other hand, the serum level of adiponectin, which plays a protective role against the metabolic syndrome, was significantly increased in the EE group. Additionally, differential analysis between Mukitake and Shiitake, mycelia from the same family, using liquid chromatography time-of-flight MS technology revealed that only seven and five compounds exist in WE and EE from Mukitake, respectively. In conclusion, the present study demonstrated that Mukitake displays at least two different physiological actions that alleviate NAFLD: one through the reduction in inflammatory damage by its suppression in MCP-1 production and the other through an increase in level of serum adiponectin and the prevention of visceral fat accumulation.
The effects of 12-week psyllium fibre supplementation or healthy diet on blood pressure and arterial stiffness in overweight and obese individuals
Authors: Pal Sebely , Khossousi Alireza , Binns Colin , Dhaliwal Satvinder , Radavelli-Bagatini Simone
Published: July 2011

Endothelial dysfunction and increased arterial stiffness occur early in the pathogenesis of the metabolic syndrome and they are both powerful independent predictors of cardiovascular risk. A high-fibre diet has been correlated with lower BMI and a lower incidence of hyperlipidaemia, CVD, hypertension and diabetes. The present randomised, parallel-design study compared the effects of fibre intake from a healthy dietv.fibre supplement diets on blood pressure (BP) and vascular function over 12 weeks. Overweight and obese adults were randomised to one of three groups: control (with placebo), fibre supplement (FIB) or healthy eating group with placebo (HLT). Systolic blood pressure (SBP) was lower in the FIB group compared with the control group at week 6, but not at week 12. However, SBP was lower in the HLT group compared with control group at week 12. At week 6, the FIB group presented lower diastolic blood pressure and augmentation index compared with the control group, but this result did not persist to the end of the study. The present study did not show any improvements in BP or vascular function in overweight and obese individuals with psyllium fibre supplementation over 12 weeks of intervention. However, a healthy diet provided the greatest improvements in BP in overweight and obese subjects. Further research with hypertensive individuals is necessary to elucidate whether increased fibre consumption in the form of psyllium supplementation may provide a safe and acceptable means to reduce BP, vascular function and the risk of developing CVD.
Literature and Revolution
Authors: Selim Samah
Published: July 2011

The three-week uprising in Egypt that ended with the removal of Husni Mubarak on February 11 happened to coincide with the section of my spring course syllabus on the Egyptian novel from Najib Mahfuz to Ahmed Alaidy. As was the case for many of my colleagues and their students, the rapid and awe-inspiring events unfolding daily before us pushed purely academic concerns to the margins of class discussion. This tidal wave of revolutionary politics erupting into the classroom forced me to the realization that my larger syllabus was not simply some neutral or systematic survey of half a century's worth of Arabic literature. I began to think about the largely invisible dystopic intellectual and historical paradigms through which modern Arabic literature is often framed, at least in the United States. The nahḍa/naksa narrative, which compelled many of us to read Arab cultural history of the 20th century as a story of brief “awakening” followed by irredeemable decline and corruption, is clearly no longer tenable in the wake of February 11. This same narrative underpinned the highly self-conscious postmodernism that began to emerge in Egypt in the 1990s and that reached its apogee a couple of decades later at the end of the 2000s, a postmodernism that was celebrated (though by no means universally) as the true beginning of literary modernity and the emancipation of the subject from the dead weight of a past ideological age.
The Hands of the Projectionist
Authors: Cartwright Lisa
Published: July 2011

Argument

This essay considers the work of projection and the hand of the projectionist as important components of the social space of the cinema as it comes into being in the nineteenth century and the early decades of the twentieth. I bring the concept of Maurice Merleau-Ponty on the place of the body as an entity that applies itself to the world “like a hand to an instrument” into a discussion of the pre-cinematic projector as an instrument that we can interpret as evidence of the experience of the work of the projectionist in the spirit of film theory and media archaeology, moving work on instrumentation in a different direction from the analysis of the work of the black box in laboratory studies. Projection is described as a psychological as well as a mechanical process. It is suggested that we interpret the projector not simply in its activity as it projects films, but in its movement from site to site and in the workings of the hand of its operator behind the scenes. This account suggests a different perspective on the cinematic turn of the nineteenth century, a concept typically approached through the study of the image, the look, the camera, and the screen.
Assembly and disassembly of a retinal cholinergic network
Authors: FORD KEVIN J. , FELLER MARLA B.
Published: July 2011

In the few weeks prior to the onset of vision, the retina undergoes a dramatic transformation. Neurons migrate into position and target appropriate synaptic partners to assemble the circuits that mediate vision. During this period of development, the retina is not silent but rather assembles and disassembles a series of transient circuits that use distinct mechanisms to generate spontaneous correlated activity called retinal waves. During the first postnatal week, this transient circuit is comprised of reciprocal cholinergic connections between starburst amacrine cells. A few days before the eyes open, these cholinergic connections are eliminated as the glutamatergic circuits involved in processing visual information are formed. Here, we discuss the assembly and disassembly of this transient cholinergic network and the role it plays in various aspects of retinal development.
The sky as a social field
Authors: Iwaniszewski Stanisław
Published: July 2011

Like other features of the surrounding world, objects and events perceived in the sky were used to mediate between humans and specific meanings acquired in relation to them. Celestial bodies were often believed to act like human agents. In this way the skies became part of the social field of human beings—a heterogeneous space in which all important types of relationships could happen. For this reason, the study of the role celestial lore and skywatching played in human populations is a task appropriate to cultural astronomers rather than to astrophysicists or historians of science.
Contributions to the study of the Muisca calendar
Authors: Izquierdo Manuel Arturo
Published: July 2011

The aim of this work is to review and expand upon the model proposed by Father José Domingo Duquesne de la Madrid (1745–1821) regarding the calendar of the pre-Columbian Muisca culture of central Colombia. This model was dismissed by scholars in the late 19th century when it was called just a simple invention of a clergyman; however, a detailed analysis shows that his interpretation of the calendar was based on genuine ethnographic information. According to Duquesne, this calendar was based on a series of moons whose multiples are 5, 20 and 37. These multiples generate time series that can be comparable to our years (37 moons), centuries (740 moons, or 59.8 years) and millennia (14800 moons or 1196 years). According to the information provided, these long time spans can be tracked up to a period of 74000 moons (5978 years). The work of Duquesne provides us some clues about the state of timekeeping traditions in pre-Columbian societies of the Intermediate Area.
Identification of astronomical objects in ancient engravings: Malargüe, Mendoza, Argentina. Methodological contributions in archaeoastronomy
Authors: Tucker Hugo , Risi Andres , Bandiera Roberto
Published: July 2011

In 2007 a group was formed to study ‘Archaeoastronomy of Malargüe’. Its main objective is to contribute to the understanding of rock art records from the study of their variability, in order to understand their functionality in the context of regional archaeological problems. The research is addressed using an interdisciplinary theoretical and methodological model, focusing on the characteristics of the site and location of the engravings, their relationship with the landscape, and the identification of possible representations of astronomical objects. In this paper, we discuss some of the theoretical and methodological tools we have used for the fieldwork and analysis, using as our case study work at the rock art sites of Agua Botada, Valle Hermoso, and Los Toscales del Payén in the south of Mendoza, Argentina.
Marine biogeochemical responses to the North Atlantic Oscillation in a coupled climate model
Authors: Patara Lavinia , Visbeck Martin , Masina Simona , Krahmann Gerd , Vichi Marcello
Published: July 2011

In this study a coupled ocean‐atmosphere model containing interactive marine biogeochemistry is used to analyze interannual, lagged, and decadal marine biogeochemical responses to the North Atlantic Oscillation (NAO), the dominant mode of North Atlantic atmospheric variability. The coupled model adequately reproduces present‐day climatologies and NAO atmospheric variability. It is shown that marine biogeochemical responses to the NAO are governed by different mechanisms according to the time scale considered. On interannual time scales, local changes in vertical mixing, caused by modifications in air‐sea heat, freshwater, and momentum fluxes, are most relevant in influencing phytoplankton growth through light and nutrient limitation mechanisms. At subpolar latitudes, deeper mixing occurring during positive NAO winters causes a slight decrease in late winter chlorophyll concentration due to light limitation and a 10%–20% increase in spring chlorophyll concentration due to higher nutrient availability. The lagged response of physical and biogeochemical properties to a high NAO winter shows some memory in the following 2 years. In particular, subsurface nutrient anomalies generated by local changes in mixing near the American coast are advected along the North Atlantic Current, where they are suggested to affect downstream chlorophyll concentration with 1 year lag. On decadal time scales, local and remote mechanisms act contemporaneously in shaping the decadal biogeochemical response to the NAO. The slow circulation adjustment, in response to NAO wind stress curl anomalies, causes a basin redistribution of heat, freshwater, and biogeochemical properties which, in turn, modifies the spatial structure of the subpolar chlorophyll bloom.
Mixing in the stratified interface of the Faroe Bank Channel overflow: The role of transverse circulation and internal waves
Authors: Seim Knut S. , Fer Ilker
Published: July 2011

The overflow of cold water across the Faroe Bank Channel sill is a significant volume flux of dense water to the North Atlantic Ocean. Using observations of hydrography, current and microstructure from a 1 week cruise and 2 month long time series from moored instruments, we address the role of transverse circulation and internal waves in mixing in the stratified 100 m thick plume‐ambient interface. The streamwise momentum budget is dominated by a balance between the pressure gradient and bottom friction; the entrainment stress is negligible. The transverse momentum budget is in geostrophic balance, and the transverse velocity variability is governed by the internal streamwise pressure gradient. The transverse geostrophic flow in the interfacial layer is opposed by the bottom Ekman transport. The shear associated with the interfacial jet lowers the Richardson number and enhances dissipation rates. Convective overturning events observed on the upslope side suggest a link between the transverse circulation and the vertical mixing on the upper slope. Several independent threads of evidence support the transverse circulation as an important mixing mechanism for the overflow plume. In the ambient, dissipation rates inferred from fine‐scale shear and density profile measurements are in good agreement with direct measurements, supporting internal wave breaking as a dominant mechanism for dissipation of turbulent energy. In the interfacial layer, spectral distribution of internal wavefield is energetic. In addition to shear‐induced mixing and entrainment in the interfacial layer, internal wave breaking is likely to be important for the dissipation of turbulent energy and should not be ignored.
Robots could assist scientists working in Greenland
Authors: Showstack Randy
Published: July 2011

GREENLAND—Tom Lane and Suk Joon Lee, recent graduates of Dartmouth University's Thayer School of Engineering, in Hanover, N. H., are standing outside in the frigid cold testing an autonomous robot that could help with scientific research and logistics in harsh polar environments. This summer, Lane, Lee, and others are at Summit Station, a U.S. National Science Foundation (NSF)–sponsored scientific research station in Greenland, fine‐tuning a battery‐powered Yeti robot as part of a team working on the NSF‐funded Cool Robot project. The station, also known as Summit Camp, is located on the highest point of the Greenland Ice Sheet (72°N, 38°W, 3200 meters above sea level) near the middle of the island. It is a proving ground this season for putting the approximately 68‐kilogram, 1‐cubic‐meter robot through its paces, including improving Yeti's mobility capabilities and field‐testing the robot. (See the electronic supplement to this Eos issue for a video of Yeti in action (http://www.agu.org/eos_elec/).) During field‐testing, plans call for the robot to collect data on elevation and snow surface characteristics, including accumulation. In addition, the robot will collect black carbon and elemental carbon particulate matter air samples around Summit Camp's power generator to help study carbon dispersion over snow.
AGU receives Crystal Bridge Award
Authors: Weaver Brenda
Published: July 2011

On 23 June the San Francisco Travel Association presented AGU with its Crystal Bridge Award, given to honor major convention customers who bring outstanding events with significant impact to San Francisco, Calif. For the past 43 years, AGU has held its Fall Meeting in San Francisco; for the past 17 years the meeting has been at San Francisco's Moscone Center. AGU is the second recipient of the Crystal Bridge Award, which last year went to Oracle.
Ion‐ion hybrid Alfvén wave resonator demonstrated
Authors: Balcerak Ernie
Published: July 2011

Theoretical calculations have indicated that in magnetized plasmas with two ion species, Alfvén waves, oscillations of the magnetic field due to plasma currents, can become trapped in a resonator. Such a resonator has now been demonstrated for the first time in a laboratory. Vincena et al. created the resonator in a magnetized plasma with hydrogen and helium ions. Their observations agreed well with theoretical predictions. Similar resonators could occur in the magnetosphere around Earth and other planets, where the resonant modes can interact with energetic particles. (Geophysical Research Letters, doi:10.1029/2011GL047399, 2011)
Seasonal anomalies in the Canary Current
Authors: Schultz Colin
Published: July 2011

Along the northwestern coast of Africa lies an important fishery, stimulated by an upwelling of cold, nutrient‐rich, deep‐ocean water. Driven by a complex convergence of ocean currents, the waters between the coast, the Portuguese island of Madeira, and the Canary Islands are known to vary dramatically throughout the year, seeing coastal current reversals near the shore and the location of the large‐scale Canary Current drifting seasonally, moving offshore in the winter before returning toward the coast in the summer. To sort out the trigger for this seasonal drift, Mason et al. produced a high‐resolution model of the Canary Current that captures details of its interaction with the coastal region where the deep water upwelling occurs. The authors found a pair of circular seasonal anomalies that they suggest control the strength and location of the Canary Current. The first, formed in late autumn, is a persistent, clockwise‐spinning region of elevated sea surface height and increased flow rates. Its counterpart, a counterclockwise‐rotating sea surface depression, is formed in the spring. Both anomalies spawn near the African coast and meander westward at around 2.6 kilometers per day, pushing their way out of the region over the course of a year. (Journal of Geophysical Research‐Oceans, doi:10.1029/2010JC006665, 2011)
Measuring the air content of the Larsen Ice Shelf
Authors: Balcerak Ernie
Published: July 2011

The surface elevation of the Larsen Ice Shelf in the Antarctic Peninsula has decreased by about 0.1 meter per year since 1992. This could be caused either by an increase in the density of firn (compacted snow) at the surface of the ice shelf or by an increase in melting of ice at the base of the shelf. Attributing the observed decrease to one of these causes would help researchers to know whether atmospheric or ocean warming is affecting the ice shelf. To do this, it is necessary to know the density or air content of the firn. However, firn air content has been measurable only with labor‐intensive ground‐based techniques. To overcome those challenges, Holland et al. developed a new method that uses radar sounding measurements to estimate air content. Using this approach, they observed spatial variations in the air content of the shelf. Overall, they found that the air content suggested that loss of air (increased firn density) could account for the observed lowering of the surface of the ice shelf, though the result does not rule out a contribution from melting at the base of the ice shelf. (Geophysical Research Letters, doi:10.1029/2011GL047245, 2011)
How the formation of Indonesia destroyed Australia's rain forest
Authors: Schultz Colin
Published: July 2011

A little more than 3 million years ago, a climatic upheaval forever changed Australia's western coast. Over the span of 200,000 years the southward flowing waters of the Leeuwin Current cooled by 2°–3°C, decreasing coastal precipitation and converting northwestern Australia's rain forests to semiarid grasslands. By measuring the isotope ratios and chemical composition of preserved shells left by ancient single‐celled organisms, Karas et al. reconstructed the hydrologic signature of the geologic upheaval that triggered the sudden cooling. During the Pliocene (approximately 4–3 million years ago), tectonic activity led to the formation of a number of small islands in the Indonesian Archipelago. This protruding land restricted the Indonesian Throughflow (ITF), a current that carries warm, fresh, tropical Pacific water through the island chain and feeds the Leeuwin Current. (Paleoceanography, doi:10.1029/2010PA001949, 2011)
Phosphoinositides and the regulation of tubular-based endosomal sorting
Authors: Cullen Peter J.
Published: July 2011

From the pioneering work of Mabel and Lowell Hokin in the 1950s, the biology of this specific isomer of hexahydroxycyclohexane and its phosphorylated derivatives, in the form of inositol phosphates and phosphoinositides, has expanded to fill virtually every corner of cell biology, whole-organism physiology and development. In the present paper, I give a personal view of the role played by phosphoinositides in regulating the function of the endosomal network, and, in so doing, highlight some of the basic properties through which phosphoinositides regulate cell function.
High sensitivity AlGaN/GaN field effect transistor protein sensors operated in the subthreshold regime by a control gate electrode
Authors: Wen Xuejin , Gupta Samit , Wang Yuji , Nicholson Theodore R. , Lee Stephen C. , Lu Wu
Published: July 2011

We demonstrate high sensitivity AlGaN/GaN field effect transistor biosensors with a control gate electrode for streptavidin detection. The device active area is functionalized with 3-Aminopropyltriethoxysilane and N-hydroxysulfosuccinimide-biotin for streptavidin binding. Without any electrochemical side effects, a gate voltage is applied through a Pt control electrode to the solution so that the device operates sensitively in the subthreshold regime. Due to the logarithmic relationship between the channel current and gate voltage in the subthreshold regime, at a concentration of 4.73 pM streptavidin, the device exhibits 9.97% current change in the subthreshold regime compared with the current in phosphate buffered saline solution. In the linear regime, the current change is 0.49% at the same streptavidin concentration.
Role of polymer matrix in large enhancement of dielectric constant in polymer-metal composites
Authors: Panda Maheswar , Srinivas V. , Thakur A. K.
Published: July 2011

Dielectric behavior of polymer (polar/nonpolar)-metal nanocomposites (PMCs) prepared under identical processing conditions have been compared. A high effective dielectric constant (ɛeff>2500) with a moderate loss and a lower ɛeff (74) with low loss was observed, respectively, for polar and nonpolar PMC at their respective percolation thresholds (fc). The results have been explained with the help of percolation theory and dipolar polarization. Similar value of fc observed in both the PMC is attributed to the same order of conductivity of polymer matrices. The dipolar polarization present in the polymer plays a major role in the enhancement of ɛeff.
Ferroelectric and antiferrodistortive phase transition in the multiferroic (Bi0.8Ba0.2)(Fe0.8Ti0.2)O3: A high temperature neutron powder diffraction study
Authors: Singh Anar , Senyshyn Anatoliy , Fuess Hartmut , Pandey Dhananjai
Published: July 2011

Presented here are the results of Rietveld analysis of powder neutron diffraction data, which reveal that both the ferroelectric and antiferrodistortive phase transitions occur together at T ∼ 925 K during heating, leading to a change in crystal structure from room temperature rhombohedral phase in the R3c space group with tilted oxygen octahedra to the high temperature paraelectric and paraelastic cubic phase in Pm3−m space group. The presence of superlattice peaks due to antiphase rotation of oxygen octahedra in the rhombohedral phase until the transition to the cubic phase precludes the possibility of an intermediate R3m space group, conjectured previously on the basis of an x-ray powder diffraction study. Discontinuous change in the unit-cell volume, tilt angle, and bond lengths at the transition temperature TC, and phase coexistence of R3c and Pm3−m over 100 K range across TC, suggest that the transition is of first order. It is argued that the R3c to Pm3−m phase transition is of trigger type involving simultaneous condensation of Γ4- and R4+ modes.
The influence of pressure relaxation on the structure of an axial vortex
Authors: Ash Robert L. , Zardadkhan Irfan , Zuckerwar Allan J.
Published: July 2011

Governing equations including the effects of pressure relaxation have been utilized to study an incompressible, steady-state viscous axial vortex with specified far-field circulation. When sound generation is attributed to a velocity gradient tensor-pressure gradient product, the modified conservation of momentum equations that result yield an exact solution for a steady, incompressible axial vortex. The vortex velocity profile has been shown to closely approximate experimental vortex measurements in air and water over a wide range of circulation-based Reynolds numbers. The influence of temperature and humidity on the pressure relaxation coefficient in air has been examined using theoretical and empirical approaches, and published axial vortex experiments have been employed to estimate the pressure relaxation coefficient in water. Non-equilibrium pressure gradient forces have been shown to balance the viscous stresses in the vortex core region, and the predicted pressure deficits that result from this non-equilibrium balance can be substantially larger than the pressure deficits predicted using a Bernoulli equation approach. Previously reported pressure deficit distributions for dust devils and tornados have been employed to validate the non-equilibrium pressure deficit predictions.
Instrumentation for fast-scan cyclic voltammetry combined with electrophysiology for behavioral experiments in freely moving animals
Authors: Takmakov Pavel , McKinney Collin J. , Carelli Regina M. , Wightman R. Mark
Published: July 2011

Fast-scan cyclic voltammetry is a unique technique for sampling dopamine concentration in the brain of rodents in vivo in real time. The combination of in vivo voltammetry with single-unit electrophysiological recording from the same microelectrode has proved to be useful in studying the relationship between animal behavior, dopamine release and unit activity. The instrumentation for these experiments described here has two unique features. First, a 2-electrode arrangement implemented for voltammetric measurements with the grounded reference electrode allows compatibility with electrophysiological measurements, iontophoresis, and multielectrode measurements. Second, we use miniaturized electronic components in the design of a small headstage that can be fixed on the rat's head and used in freely moving animals.
The quantum free particle on spherical and hyperbolic spaces: A curvature dependent approach
Authors: Cariñena José F. , Rañada Manuel F. , Santander Mariano
Published: July 2011

The quantum free particle on the sphere \documentclass[12pt]{minimal}\begin{document}$S_\kappa ^2$\end{document}Sκ2 (κ > 0) and on the hyperbolic plane \documentclass[12pt]{minimal}\begin{document}$H_\kappa ^2$\end{document}Hκ2 (κ < 0) is studied using a formalism that considers the curvature κ as a parameter. The first part is mainly concerned with the analysis of some geometric formalisms appropriate for the description of the dynamics on the spaces (\documentclass[12pt]{minimal}\begin{document}$S_\kappa ^2$\end{document}Sκ2, \documentclass[12pt]{minimal}\begin{document}${\rm I\hspace{-1.79993pt}R}^2$\end{document}IR2, \documentclass[12pt]{minimal}\begin{document}$H_\kappa ^2$\end{document}Hκ2) and with the transition from the classical κ-dependent system to the quantum one using the quantization of the Noether momenta. The Schrödinger separability and the quantum superintegrability are also discussed. The second part is devoted to the resolution of the κ-dependent Schrödinger equation. First the characterization of the κ-dependent “curved” plane waves is analyzed and then the specific properties of the spherical case are studied with great detail. It is proved that if κ > 0 then a discrete spectrum is obtained. The wavefunctions, that are related with a κ-dependent family of orthogonal polynomials, are explicitly obtained.