bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinguishing Positional Uncertainty from True Mobility in Single-Molecule Trajectories That Exhibit Multiple Diffusive Modes
Authors: Kastantin Mark , Schwartz Daniel K.
Published: July 2012

Although imperfect spatial localization in single-molecule object tracking experiments has long been recognized to induce apparent motion in an immobile population of molecules, this effect is often ignored or incorrectly analyzed for mobile molecules. In particular, apparent motion due to positional uncertainty is often incorrectly assigned as a distinct diffusive mode. Here we show that, due to both static and dynamic contributions, positional uncertainty does not introduce a new apparent diffusive mode into trajectories, but instead causes a systematic shift of each measured diffusion coefficient. This shift is relatively simple: a factor of σ2/Δt is added to each diffusion coefficient, where σ is the positional uncertainty length scale and Δt is the time interval between observations. Therefore, by calculating the apparent diffusion coefficients as a function of Δt, it is straightforward to separate the true diffusion coefficients from the effective positional uncertainty. As a concrete demonstration, we apply this approach to the diffusion of the protein fibrinogen adsorbed to a hydrophobic surface, a system that exhibits three distinct modes of diffusion.
RAYLEIGH–TAYLOR INSTABILITIES IN AXI-SYMMETRIC OUTFLOW FROM A POINT SOURCE
Authors: FORBES LAWRENCE K.
Published: July 2012

This paper studies outflow of a light fluid from a point source, starting from an initially spherical bubble. This region of light fluid is embedded in a heavy fluid, from which it is separated by a thin interface. A gravitational force directed radially inward toward the mass source is permitted. Because the light inner fluid is pushing the heavy outer fluid, the interface between them may be unstable to small perturbations, in the Rayleigh–Taylor sense. An inviscid model of this two-layer flow is presented, and a linearized solution is developed for early times. It is argued that the inviscid solution develops a point of infinite curvature at the interface within finite time, after which the solution fails to exist. A Boussinesq viscous model is then presented as a means of quantifying the precise effects of viscosity. The interface is represented as a narrow region of large density gradient. The viscous results agree well with the inviscid theory at early times, but the curvature singularity of the inviscid theory is instead replaced by jet formation in the viscous case. This may be of relevance to underwater explosions and stellar evolution.
Feline gastrointestinal microbiota
Authors: Minamoto Yasushi , Hooda Seema , Swanson Kelly S. , Suchodolski Jan S.
Published: July 2012

The close relationship between gastrointestinal (GI) microbiota and its host has an impact on the health status of an animal that reaches beyond the GI tract. A balanced microbiome stimulates the immune system, aids in the competitive exclusion of transient pathogens and provides nutritional benefits to the host. With recent rapid advances in high-throughput sequencing technology, molecular approaches have become the routinely used tools for ecological studies of the feline microbiome, and have revealed a highly diverse and complex intestinal ecosystem in the feline GI tract. The major bacterial groups are similar to those found in other mammals, withFirmicutes,Bacteroidetes,ActinobacteriaandProteobacteriaconstituting more than 99% of intestinal microbiota. Several nutritional studies have demonstrated that the feline microbiota can be modulated by the amount of soluble fibers (i.e., prebiotics) and macronutrients (i.e., protein content) in the diet. Initial clinical studies have suggested the presence of a dysbiosis in feline inflammatory bowel disease (IBD). Recently, metagenomic approaches have attempted to characterize the microbial gene pool. However, more studies are needed to describe the phylogenetic and functional changes in the intestinal microbiome in disease states and in response to environmental and dietary modulations. This paper reviews recent studies cataloging the microbial phylotypes in the GI tract of cats.
The intestinal microbiota in the rat model: major breakthroughs from new technologies
Authors: Tomas Julie , Langella Philippe , Cherbuy Claire
Published: July 2012

The mammalian intestine harbors a large and diverse community of micro-organisms, known as the intestinal microbiota. Recent developments in molecular profiling methods, mainly based on microbial 16S ribosomal RNA gene sequencing, have provided unprecedented insights into the make-up and diversity of intestinal microbial communities. Using these culture-independent analyses, gut microbiota of several mammals including laboratory rodents, have been revisited. The laboratory rat is one of the major species bred and kept for scientific research. Although this animal is bred in confined environments and subjected to procedures for satisfying health requirements that hamper natural colonization, some major features of mammalian gut microbiota are conserved. However, the gut microbiota varies according to the breeding conditions of the rats and this could impact reproducibility of the experimental models. Determining the non-pathogenic microbial community might be relevant in standards of quality control of laboratory animals. Molecular profiling techniques could be applied to document this information.
The microbiome of the chicken gastrointestinal tract
Authors: Yeoman Carl J. , Chia Nicholas , Jeraldo Patricio , Sipos Maksim , Goldenfeld Nigel D. , White Bryan A.
Published: July 2012

The modern molecular biology movement was developed in the 1960s with the conglomeration of biology, chemistry, and physics. Today, molecular biology is an integral part of studies aimed at understanding the evolution and ecology of gastrointestinal microbial communities. Molecular techniques have led to significant gains in our understanding of the chicken gastrointestinal microbiome. New advances, primarily in DNA sequencing technologies, have equipped researchers with the ability to explore these communities at an unprecedented level. A reinvigorated movement in systems biology offers a renewed promise in obtaining a more complete understanding of chicken gastrointestinal microbiome dynamics and their contributions to increasing productivity, food value, security, and safety as well as reducing the public health impact of raising production animals. Here, we contextualize the contributions molecular biology has already made to our understanding of the chicken gastrointestinal microbiome and propose targeted research directions that could further exploit molecular technologies to improve the economy of the poultry industry.
“The Notorious Mrs. Clem”: Gender, Class, and Criminality in Gilded Age America
Authors: Gamber Wendy
Published: July 2012

This essay explores the story of Nancy Clem, an outwardly respectable Indianapolis confidence woman and alleged murderess, in the context of changing constructions of class, gender, and criminality. It examines various ways in which lawyers, newspaper reporters, and ordinary citizens struggled to understand a woman who did not fit preexisting conceptions of gender and crime. A series of high-profile cases involving bourgeois criminals and (more than likely) Clem's own social aspirations allowed cultural commentators to portray her as a “genteel murderess.” Upon her release from prison after an abortive fifth trial, Clem could not sustain her newly acquired social identity, in part because her erstwhile refinement was a journalistic creation and in part because the changing nature of class, gender, and space in Gilded Age Indianapolis provided her with fewer opportunities for self-fashioning. Clem's social odyssey from half-literate “Butternut” to genteel murderess to uncultured “capitalist” reflects slippery, yet significant, transitions between social fluidity and relative rigidity, antebellum respectability and Gilded Age gentility.
“Killing the Elephant”: Murderous Beasts and the Thrill of Retribution, 1885–1930
Authors: Wood Amy Louise
Published: July 2012

At the turn of the last century, circus elephants who had, in fits of distemper, killed circus trainers, workers, or spectators were regularly put to death. That alone is not extraordinary. What is fascinating is that the killings of these animals were not infrequently staged as public executions, with the elephant playing the role of the menacing criminal facing his just rewards before a crowd of eager witnesses. News accounts in turn reported these events as they would criminal executions, framing them as stories of murder, remorse, and retribution. This article treats these remarkable events as complex rituals through which larger tensions and conflicts surrounding crime and punishment in this period became manifest. These executions, performed as extensions of the modern circus, were commercial spectacles in and of the industrial age. Still, like circuses, they were also events full of ambivalence about this new age, as they acted out popular controversies over the nature of criminality, the meaning of justice, and the role of vengeance in modern life.
The nature and significance of solar minima
Authors: Priest Eric
Published: July 2012

As an introduction to the theme of this symposium, I give a simple review of the photospheric magnetic field, the properties of the solar cycle, the way in which the magnetic field is thought to be generated by dynamo action, and finally the unusual properties of the recent solar minimum. This has awakened an interest in improving predictions of the solar cycle and in the nature of solar minima not just as gaps between maxima but as phenomena of intrinsic interest in their own right.
Solar and stellar activity: diagnostics and indices
Authors: Judge Philip G. , Thompson Michael J.
Published: July 2012

We summarize the fifty-year concerted effort to place the “activity” of the Sun in the context of the stars. As a working definition of solar activity in the context of stars, we adopt thoseglobally–observablevariations on time scales below thermal time scales, of ~105yr for the convection zone. So defined, activity is dominated by magnetic–field evolution, including the 22–year Hale cycle, the typical time it takes for the quasi-periodic reversal in which the global magnetic–field takes place. This is accompanied by sunspot variations with 11 year periods, known since the time of Schwabe, as well as faster variations due to rotation of active regions and flaring. “Diagnostics and indices” are terms given to theindirectsignatures of varying magnetic–fields, including the photometric (broad-band) variations associated with the sunspot cycle, and variations of the accompanying heated plasma in higher layers of stellar atmospheres seen at special optical wavelengths, and UV and X-ray wavelengths. Our attention is also focussed on the theme of the Symposium by examining evidence for deep and extended minima of stars, and placing the 70–year long solar Maunder Minimum into a stellar context.
How well do we know the sunspot number?
Authors: Svalgaard Leif
Published: July 2012

We show that only two adjustments are necessary to harmonize the Group Sunspot Number with the Zürich Sunspot Number. The latter has been increased from the 1940s on to the present by 20% due to weighting of sunspot counts according to size of the spots and can be corrected by increasing the earlier values as well. The Group Sunspot Number before ~1885 is too low by ~50%. With these adjustments a single sunspot number series results. Of note is that there is no longer a distinct Modern Grand Maximum.
Helioseismology - a clear view of the interior
Authors: Elsworth Yvonne , Broomhall Anne-Marie , Chaplin William
Published: July 2012

Helioseismology is a very powerful tool that allows us to explore the interior of the Sun. Here we give particular emphasis to the justification for the likely location of the zone that is most sensitive to cycle-related changes. For the low degree modes we find that more than one timescale for changes in the oscillations is discovered. We also note the successive cycles have differing sensitivities to the activity. We end with a warning of the risk of being misled with short datasets such as are seen with stellar data.
Reconstruction of magnetic field surges to the poles from sunspot impulses
Authors: Zolotova Nadezhda V. , Ponyavin Dmitri I.
Published: July 2012

The time-latitude diagram of the photospheric magnetic field of the Sun during 1975-2011 (Kitt Peak NSO, SOLIS NSO, SOHO MDI data) is analyzed using Gnevysvev's idea of impulsed structure of sunspot cycle and a flux transport concept. It is demonstrated that poleward migrations of magnetic trailing polarities are closely associated with the impulses of sunspot activity. We use a fitting procedure to reconstruct the sunspot impulses and poleward magnetic field surges. We compare our results for Cycle 22 model with the time-latitude diagram of the photospheric magnetic field of the Sun.
Towards the reconstruction of the EUV irradiance for solar Cycle 23
Authors: Haberreiter Margit
Published: July 2012

We present preliminary reconstructions of the EUV from 26 to 34 nm from February 1997 to May 2005, covering most of solar cycle 23. The reconstruction is based on synthetic EUV spectra calculated with the spectral synthesis code Solar Modeling in 3D (SolMod3D). These spectra are weighted by the relative area coverage of the coronal features as identified from EIT images. The calculations are based on one-dimensional atmospheric structures that represent a temporal and spatial mean of the chromosphere, transition region, and corona. The employed segmentation analysis considers coronal holes, the quiet corona, and active regions identified on the solar disk. The reconstructed EUV irradiance shows a good agreement with observations taken with the CELIAS/SEM instrument onboard SOHO. Further improvement of the reconstruction including more solar features as well as the off-limb detection of activity features will be addressed in the near future.
Polar magnetic fields and coronal holes during the recent solar minima
Authors: de Toma Giuliana
Published: July 2012

The slow decline of solar Cycle 23 combined with the slow rise of Cycle 24 resulted in a very long period of low magnetic activity during the years 2007–2009 with sunspot number reaching the lowest level since 1913. This long solar minimum was characterized by weak polar magnetic fields, smaller polar coronal holes, and a relatively complex coronal morphology with multiple streamers extending to mid latitudes. At the same time, low latitude coronal holes remained present on the Sun until the end of 2008 modulating the solar wind at the Earth in co-rotating, fast solar wind streams. This magnetic configuration was remarkably different from the one observed during the previous two solar minima when coronal streamers were confined near the equator and the fast solar wind was mainly originating from the large coronal holes around the Sun's poles. This paper presents the evolution of the polar magnetic fields and coronal holes during the past minimum, compare it with the previous minima, and discuss the implications for the solar wind near the Earth. It also considers the minimum of Cycle 23 in an historical perspective and, in particular, compares it to the long minima at the turn of the 19th century.
Magnetic clouds along the solar cycle: expansion and magnetic helicity
Authors: Dasso Sergio , Démoulin Pascal , Gulisano Adriana M.
Published: July 2012

Magnetic clouds (MCs) are objects of extreme importance in the heliosphere. They have a major role on releasing magnetic helicity from the Sun (with crucial consequences on the solar dynamo), they are the hugest transient object in the interplanetary medium, and the main actors for the Sun-Earth coupling. The comparison between models and observations is beginning to clarify several open questions on MCs, such as their internal magnetic configuration and their interaction with the ambient solar wind. Due to the decay of the solar wind pressure with the distance to the Sun, MCs are typically in expansion. However, their detailed and local expansion properties depend on their environment plasma properties. On the other hand, while it is well known that the solar cycle determines several properties of the heliosphere, the effects of the cycle on MC properties are not so well understood. In this work we review two major properties of MCs: (i) their expansion, and (ii) the magnetic flux and helicity that they transport through the interplanetary medium. We find that the amount of magnetic flux and helicity released via MCs during the last solar minimum (years 2007-2009) was significantly lower than in the previous one (years 1995-1997). Moreover, both MC size and mean velocity are in phase with the solar cycle while the expansion rate is weakly variable and has no relationship with the cycle.
Modeling of the atmospheric response to a strong decrease of the solar activity
Authors: Rozanov Eugene V. , Egorova Tatiana A. , Shapiro Alexander I. , Schmutz Werner K.
Published: July 2012

We estimate the consequences of a potential strong decrease of the solar activity using the model simulations of the future driven by pure anthropogenic forcing as well as its combination with different solar activity related factors: total solar irradiance, spectral solar irradiance, energetic electron precipitation, solar protons and galactic cosmic rays. The comparison of the model simulations shows that introduced strong decrease of solar activity can lead to some delay of the ozone recovery and partially compensate greenhouse warming acting in the direction opposite to anthropogenic effects. The model results also show that all considered solar forcings are important in different atmospheric layers and geographical regions. However, in the global scale the solar irradiance variability can be considered as the most important solar forcing. The obtained results constitute probably the upper limit of the possible solar influence. Development of the better constrained set of future solar forcings is necessary to address the problem of future climate and ozone layer with more confidence.
Coronal Mass Ejection deflection in the corona during the two last solar minima
Authors: López Fernando Marcelo , Cremades Hebe , Balmaceda Laura
Published: July 2012

In the framework of the IAU Working Group on Comparative Solar Minima, we investigate the latitudinal deflection of Coronal Mass Ejections (CMEs) with respect to the location of their uniquely identified solar source regions. Data compiled during the Whole Sun Month (WSM) and Whole Heliosphere Interval (WHI) campaigns allowed for comparisons between the two last solar minima.

The analysis of the coronal streamers’ distribution during these intervals led to study of the dependence of CME deflection on the angular separation between their source regions and the nearest streamer. All performed analyses consider exclusively projected structures on the plane of the sky, disregarding longitudinal deflections as well.

The results of the present study indicate that for both minima most of the events (62.5% for WSM, 84.2% for WHI) are deflected towards the nearest streamer, following the boundary conditions imposed by the heliospheric current sheet.

Most of the deflections found in the WHI period could be explained by the more complex structure in the global distribution of magnetic field present during that minimum. On the other hand, the low number of events detected during the WSM period hinders the statistical comparison between both campaigns.
High-speed streams in the solar wind during the last solar minimum
Authors: Maris Georgeta , Maris Ovidiu , Oprea Constantin , Mierla Marilena
Published: July 2012

The paper presents a statistical analysis of the fast solar wind streams during the last prolonged minimum. Defining a minimum phase as the period with the monthly relative sunspot numbers (smoothed values) having a value of less than 20, we considered for this analysis the interval February 2006 September 2010. The High-Speed Streams (HSSs) in the solar wind were determined by their main parameters: duration, maximum velocity, velocity gradient. A comparative analysis of the HSS dynamics during the last solar minimum with the previous solar minimum (1996-1997) concludes the paper.
The 3D solar corona Cycle 24 rising phase from SDO/AIA tomography
Authors: Nuevo Federico A. , Vásquez Alberto M. , Frazin Richard A. , Huang Zhenguang , Manchester Ward B.
Published: July 2012

We recently extended the differential emission measure tomography (DEMT) technique to be applied to the six iron bands of the Atmospheric Imaging Assembly (AIA) instrument aboard the Solar Dynamics Observatory (SDO). DEMT products are the 3D reconstruction of the coronal emissivity in the instrument's bands, and the 3D distribution of the local differential emission measure, in the height range 1.0 to 1.25 R⊙. We show here derived maps of the electron density and temperature of the inner solar corona during the rising phase of solar Cycle 24. We discuss the distribution of our results in the context of open/closed magnetic regions, as derived from a global potential field source surface (PFSS) model of the same period. We also compare the results derived with SDO/AIA to those derived with the Extreme UltraViolet Imager (EUVI) instrument aboard the Solar TErrestrial RElations Observatory (STEREO).
Very intense geomagnetic storms: solar sources, characteristics and cycle distribution
Authors: Szajko Natalia , Cristiani Germán , Mandrini Cristina H. , Dal Lago Alisson
Published: July 2012

We revisit previous studies in which the characteristics of the solar and interplanetary sources of intense geomagnetic storms have been discussed. We consider the very intense geomagnetic storms that occurred during Solar Cycle 23 by setting a value of Dstmin ≤ −200 nT as threshold. We have identified and characterized the solar and interplanetary sources of each storm. After this, we investigate the overall characteristics of the interplanetary (IP) main-phase storm driver, including the time arrival of the shock/disturbance at 1 AU, the type of associated IP structure/ejecta, the origin of a prolonged and enhanced southward component (Bz) of the IP field, and other characteristics related to the energy injected into the magnetosphere during the storm.
Precise effective temperatures of solar analog stars
Authors: Cornejo-Espinoza D. , Ramírez I. , Barklem P. S. , Guevara-Day W.
Published: July 2012

We perform a study of 62 solar analog stars to compute their effective temperatures (Teff) using the Balmer line wing fitting procedure and compare them with Teff values obtained using other commonly employed methods. We use observed Hα spectral lines and a fine grid of theoretical LTE model spectra calculated with the best available atomic data and most recent quantum theory. Our spectroscopic data are of very high quality and have been carefully normalized to recover the proper shape of the Hα line profile. We obtain Teff values with internal errors of about 25K. Comparison of our results with those from other methods shows reasonably good agreement. Then, combining Teff values obtained from four independent techniques, we are able to determine final Teff values with errors of about 10K.
Stars in magnetic grand minima: where are they and what are they like?
Authors: Saar Steven H. , Testa Paola
Published: July 2012

We explore various ideas of what a star in a Maunder-like magnetic minimum would look like, and ways of finding stars in such a state, and make some estimates of their physical and magnetic activity properties. We discuss new X-ray observations of a small selection of candidates for being in magnetic grand minima. These are then compared with the Sun and other low activity stars.
Soft X-ray emission as diagnostics for Maunder minimum stars
Authors: Poppenhaeger Katja , Schmitt Jürgen H. M. M.
Published: July 2012

The identification of stars in a Maunder minimum state purely from their chromospheric emission (for example in Ca II lines) has proven to be difficult. Photospheric contributions, metallicities and possible deviations from the main sequence stage may lead to very low values of the traditional chromospheric activity indicators, while no Maunder minimum state may be present. X-ray observations can be a key tool for identifying possible Maunder minimum stars: We have detected very soft X-ray emission from low-temperature coronal plasma, similar to emission from solar coronal holes, in several stars with very low chromospheric activity indicators. The coronal properties inferred from X-ray observations can therefore yield a crucial piece of information to verify Maunder minimum states in stars.
Dynamo models of grand minima
Authors: Choudhuri Arnab Rai
Published: July 2012

Since a universally accepted dynamo model of grand minima does not exist at the present time, we concentrate on the physical processes which may be behind the grand minima. After summarizing the relevant observational data, we make the point that, while the usual sources of irregularities of solar cycles may be sufficient to cause a grand minimum, the solar dynamo has to operate somewhat differently from the normal to bring the Sun out of the grand minimum. We then consider three possible sources of irregularities in the solar dynamo: (i) nonlinear effects; (ii) fluctuations in the poloidal field generation process; (iii) fluctuations in the meridional circulation. We conclude that (i) is unlikely to be the cause behind grand minima, but a combination of (ii) and (iii) may cause them. If fluctuations make the poloidal field fall much below the average or make the meridional circulation significantly weaker, then the Sun may be pushed into a grand minimum.
A model for grand minima and geomagnetic reversals
Authors: Sokoloff D. D. , Sobko G. S. , Trukhin V. I. , Zadkov V. N.
Published: July 2012

We suggest a simple dynamical system which mimics a nonlinear dynamo which is able to provide (in specific domains of its parametric space) the temporal evolution of solar magnetic activity cycles as well as evolution of geomagnetic field including its polarity reversals. A qualitative explanation for the physical nature of both phenomena is presented and discussed.
Effects of solar variability on planetary plasma environments and habitability
Authors: Bertucci César
Published: July 2012

Intrinsic and induced planetary magnetospheres are the result of the transfer of energy and linear momentum between the solar wind and, respectively, the magnetic field and the atmospheres of solar system bodies. This transfer seems to be, however, more critical to the atmospheric evolution of unmagnetized objects such as Mars and Venus, as locally ionized planetary particles are accelerated by solar-wind induced electric fields, leading to atmospheric escape. The nature of the obstacle to the solar wind being different, intrinsic and induced magnetospheres respond differently to solar cycle changes in solar photon flux and solar wind properties. The influence of solar variability on planetary magnetospheres and its implications for atmospheric evolution based upon remote and in situ spacecraft measurements, and numerical simulations are discussed. In particular, the case of unmagnetized objects where non-thermal escape process might have played a role in their habitability conditions is considered.
Flares and habitability
Authors: Abrevaya Ximena C. , Cortón Eduardo , Mauas Pablo J. D.
Published: July 2012

At present, dwarf M stars are being considered as potential hosts for habitable planets. However, an important fraction of these stars are flare stars, which among other kind of radiation, emit large amounts of UV radiation during flares, and it is unknown how this events can affect life, since biological systems are particularly vulnerable to UV. In this work we evaluate a well known dMe star, EV Lacertae (GJ 873) as a potential host for the emergence and evolution of life, focusing on the effects of the UV emission associated with flare activity. Since UV-C is particularly harmful for living organisms, we studied the effect of UV-C radiation on halophile archaea cultures. The halophile archaea or haloarchaea are extremophile microorganisms, which inhabit in hypersaline environments and which show several mechanisms to cope with UV radiation since they are naturally exposed to intense solar UV radiation on Earth. To select the irradiance to be tested, we considered a moderate flare on this star. We obtained the mean value for the UV-C irradiance integrating the IUE spectrum in the impulsive phase, and considering a hypothetical planet in the center of the liquid water habitability zone. To select the irradiation times we took the most frequent duration of flares on this star which is from 9 to 27 minutes. Our results show that even after considerable UV damage, the haloarchaeal cells survive at the tested doses, showing that this kind of life could survive in a relatively hostile UV environment.
Parallels among the “music scores” of solar cycles, space weather and Earth's climate
Authors: Kolláth Zoltán , Oláh Katalin , van Driel-Gesztelyi Lidia
Published: July 2012

Solar variability and its effects on the physical variability of our (space) environment produces complex signals. In the indicators of solar activity at least four independent cyclic components can be identified, all of them with temporal variations in their timescales.

Time-frequency distributions (see Kolláth & Oláh 2009) are perfect tools to disclose the “music scores” in these complex time series. Special features in the time-frequency distributions, like frequency splitting, or modulations on different timescales provide clues, which can reveal similar trends among different indices like sunspot numbers, interplanetary magnetic field strength in the Earth's neighborhood and climate data.

On the pseudo-Wigner Distribution (PWD) the frequency splitting of all the three main components (the Gleissberg and Schwabe cycles, and an ≈5.5 year signal originating from cycle asymmetry, i.e. the Waldmeier effect) can be identified as a “bubble” shaped structure after 1950. The same frequency splitting feature can also be found in the heliospheric magnetic field data and the microwave radio flux.
A cellular automaton model for coronal heating
Authors: Fuentes M. C. López , Klimchuk J. A.
Published: July 2012

We present a simple coronal heating model based on a cellular automaton approach. Following Parker's suggestion (1988), we consider the corona to be made up of elemental magnetic strands that accumulate magnetic stress due to the photospheric displacements of their footpoints. Magnetic energy is eventually released in small scale reconnection events. The model consists of a 2D grid in which strand footpoints travel with random displacements simulating convective motions. Each time two strands interact, a critical condition is tested (as in self-organized critical models), and if the condition is fulfilled, the strands reconnect and energy is released. We model the plasma response to the heating events and obtain synthetic observations. We compare the output of the model with real observations from Hinode/XRT and discuss the implications of our results for coronal heating.
The Change in Cervical Length Over Time as a Predictor of Preterm Delivery in Asymptomatic Women With Twin Pregnancies Who Have a Normal Mid-Trimester Cervical Length
Authors: Oh Kyung Joon , Park Kyo Hoon , Jeong Eun Ha , Lee Sung Youn , Ryu Aeli , Kim Shi-Nae
Published: July 2012

Aim:To determine whether or not the change in cervical length (CL) over time is valuable in predicting spontaneous preterm delivery (SPTD) in asymptomatic twin pregnancies with a normal mid-trimester CL (>25 mm).Methods:This was a prospective study including 190 consecutive asymptomatic twin gestations with a CL > 25 mm at 20–24 weeks. The women underwent an initial CL measurement at the time of routine ultrasound examination between 20 and 24 weeks’ gestation, followed 4–5 weeks later by a repeat CL measurement. The primary outcome measure was SPTD at <32 completed weeks’ gestation. Multicollinearity was a concern in the multivariable model since change in CL and follow-up CL were highly correlated.Results:The rate of SPTD at <32 weeks was 4.2%. Multiple logistic regression analyses demonstrated that the change in CL and the follow-up CL were significantly associated with SPTD before 32 weeks after adjusting for baseline covariate such as in vitro fertilization. The best cut-off values for the prediction of SPTD at <32 weeks’ gestation were 13% for the change in CL with a sensitivity of 87.5% and a specificity of 63.2%. There was no significant difference in the area under the receiver operating characteristic curves between the change in CL and the follow-up CL.Conclusions:A greater change in CL is a good predictor of SPTD in asymptomatic twin pregnancies with a normal mid-trimester CL. However, the change in CL cannot provide data beyond the follow-up CL. In the setting of a normal mid-trimester CL, a follow-up CL measurement should be considered in asymptomatic twin pregnancies.
Meconium Peritonitis in Both Fetuses With Early Twin-to-Twin Transfusion Syndrome
Authors: Marcellin Louis , Quintana Andrea , Essaoui Mohamed , Anselem Olivia , Beaudoin Sylvie , El Ayoubi Mayas , Boujenah Laurence , Salhi Houria , Tsatsaris Vassili
Published: July 2012

Twin-to-twin transfusion syndrome (TTTS) is due to unbalanced inter-twin bloodflow through placental vascular anastomoses. We present a TTTS case treated with fetoscopic laser photocoagulation (FLP) that was complicated by perinatal meconium peritonitis in both twins. Ten weeks following laser treatment, the two fetuses showed intra-abdominal hyperechogenicity and ascites. After birth, the two newborns were surgically managed for peritonitis. We discuss the pathogenesis of this double insult. The present case highlights the role of end-circulation bowel thrombi as the potential cause of subsequent intestinal perforation.
Late thrusting extensional collapse at the mountain front of the northern Apennines (Italy)
Authors: Tavani Stefano , Storti Fabrizio , Bausà Jordi , Muñoz Josep A.
Published: July 2012

Thrust‐related anticlines exposed at the mountain front of the Cenozoic Appenninic thrust‐and‐fold belt share the presence of hinterlandward dipping extensional fault zones running parallel to the hosting anticlines. These fault zones downthrow the crests and the backlimbs with displacements lower than, but comparable to, the uplift of the hosting anticline. Contrasting information feeds a debate about the relative timing between thrust‐related folding and beginning of extensional faulting, since several extensional episodes, spanning from early Jurassic to Quaternary, are documented in the central and northern Apennines. Mesostructural data were collected in the frontal anticline of the Sibillini thrust sheet, the mountain front in the Umbria‐Marche sector of the northern Apennines, with the aim of fully constraining the stress history recorded in the deformed multilayer. Compressional structures developed during thrust propagation and fold growth, mostly locating in the fold limbs. Extensional elements striking about perpendicular to the shortening direction developed during two distinct episodes: before fold growth, when the area deformed by outer‐arc extension in the peripheral bulge, and during a late to post thrusting stage. Most of the the extensional deformation occurred during the second stage, when the syn‐thrusting erosional exhumation of the structures caused the development of pervasive longitudinal extensional fracturing in the crestal sector of the growing anticline, which anticipated the subsequent widespread Quaternary extensional tectonics.
The nature and causes of the global water crisis: Syndromes from a meta‐analysis of coupled human‐water studies
Authors: Srinivasan V. , Lambin E. F. , Gorelick S. M. , Thompson B. H. , Rozelle S.
Published: July 2012

Freshwater scarcity has been cited as the major crisis of the 21st century, but it is surprisingly hard to describe the nature of the global water crisis. We conducted a meta‐analysis of 22 coupled human–water system case studies, using qualitative comparison analysis (QCA) to identify water resource system outcomes and the factors that drive them. The cases exhibited different outcomes for human wellbeing that could be grouped into a six “syndromes”: groundwater depletion, ecological destruction, drought‐driven conflicts, unmet subsistence needs, resource capture by elite, and water reallocation to nature. For syndromes that were not successful adaptations, three characteristics gave cause for concern: (1) unsustainability—a decline in the water stock or ecosystem function that could result in a long‐term steep decline in future human wellbeing; (2) vulnerability—high variability in water resource availability combined with inadequate coping capacity, leading to temporary drops in human wellbeing; (3) chronic scarcity—persistent inadequate access and hence low conditions of human wellbeing. All syndromes could be explained by a limited set of causal factors that fell into four categories: demand changes, supply changes, governance systems, and infrastructure/technology. By considering basins as members of syndrome classes and tracing common causal pathways of water crises, water resource analysts and planners might develop improved water policies aimed at reducing vulnerability, inequity, and unsustainability of freshwater systems.
Long recovery VLF perturbations associated with lightning discharges
Authors: Salut M. M. , Abdullah M. , Graf K. L. , Cohen M. B. , Cotts B. R. T. , Kumar Sushil
Published: July 2012

Long D‐region ionospheric recovery perturbations are a recently discovered and poorly understood subcategory of early VLF events, distinguished by exceptionally long ionospheric recovery times of up to 20 min (compared to more typical ∼1 min recovery times). Characteristics and occurrence rates of long ionospheric recovery events on the NWC transmitter signal recorded at Malaysia are presented. 48 long recovery events were observed. The location of the causative lightning discharge for each event is determined from GLD360 and WWLLN data, and each discharge is categorized as being over land or sea. Results provide strong evidence that long recovery events are attributed predominately to lightning discharges occurring over the sea, despite the fact that lightning activity in the region is more prevalent over land. Of the 48 long recovery events, 42 were attributed to lightning activity over water. Analysis of the causative lightning of long recovery events in comparison to all early VLF events reveals that these long recovery events are detectable for lighting discharges at larger distances from the signal path, indicating a different scattering pattern for long recovery events.
Nitrification expanded: discovery, physiology and genomics of a nitrite-oxidizing bacterium from the phylum Chloroflexi
Authors: Sorokin Dimitry Y , Lücker Sebastian , Vejmelkova Dana , Kostrikina Nadezhda A , Kleerebezem Robbert , Rijpstra W Irene C , Damsté Jaap S Sinninghe , Le Paslier Denis , Muyzer Gerard , Wagner Michael , van Loosdrecht Mark C M , Daims Holger
Published: July 2012

Nitrite-oxidizing bacteria (NOB) catalyze the second step of nitrification, a major process of the biogeochemical nitrogen cycle, but the recognized diversity of this guild is surprisingly low and only two bacterial phyla contain known NOB. Here, we report on the discovery of a chemolithoautotrophic nitrite oxidizer that belongs to the widespread phylum Chloroflexi not previously known to contain any nitrifying organism. This organism, named Nitrolancetus hollandicus, was isolated from a nitrifying reactor. Its tolerance to a broad temperature range (25–63 °C) and low affinity for nitrite (Ks=1 mm), a complex layered cell envelope that stains Gram positive, and uncommon membrane lipids composed of 1,2-diols distinguish N. hollandicus from all other known nitrite oxidizers. N. hollandicus grows on nitrite and CO2, and is able to use formate as a source of energy and carbon. Genome sequencing and analysis of N. hollandicus revealed the presence of all genes required for CO2 fixation by the Calvin cycle and a nitrite oxidoreductase (NXR) similar to the NXR forms of the proteobacterial nitrite oxidizers, Nitrobacter and Nitrococcus. Comparative genomic analysis of the nxr loci unexpectedly indicated functionally important lateral gene transfer events between Nitrolancetus and other NOB carrying a cytoplasmic NXR, suggesting that horizontal transfer of the NXR module was a major driver for the spread of the capability to gain energy from nitrite oxidation during bacterial evolution. The surprising discovery of N. hollandicus significantly extends the known diversity of nitrifying organisms and likely will have implications for future research on nitrification in natural and engineered ecosystems.
A biomolecular isolation framework for eco-systems biology
Authors: Roume Hugo , EL Muller Emilie , Cordes Thekla , Renaut Jenny , Hiller Karsten , Wilmes Paul
Published: July 2012

Mixed microbial communities are complex, dynamic and heterogeneous. It is therefore essential that biomolecular fractions obtained for high-throughput omic analyses are representative of single samples to facilitate meaningful data integration, analysis and modeling. We have developed a new methodological framework for the reproducible isolation of high-quality genomic DNA, large and small RNA, proteins, and polar and non-polar metabolites from single unique mixed microbial community samples. The methodology is based around reproducible cryogenic sample preservation and cell lysis. Metabolites are extracted first using organic solvents, followed by the sequential isolation of nucleic acids and proteins using chromatographic spin columns. The methodology was validated by comparison to traditional dedicated and simultaneous biomolecular isolation methods. To prove the broad applicability of the methodology, we applied it to microbial consortia of biotechnological, environmental and biomedical research interest. The developed methodological framework lays the foundation for standardized molecular eco-systematic studies on a range of different microbial communities in the future.
Enantio- and diastereocontrolled conversion of chiral epoxides to trans-cyclopropane carboxylates: application to the synthesis of cascarillic acid, grenadamide and l-(−)-CCG-II
Authors: Kumar Pradeep , Dubey Abhishek , Harbindu Anand
Published: July 2012

A very concise and practical synthesis of cascarillic acid, grenadamide and l-CCG-II, a cyclopropane containing natural products is accomplished employing Wadsworth-Emmons cyclopropanation reaction as key step.
Regulating the psyche: the essential contribution of Kant
Authors: Kime Philip
Published: July 2012

Jung's difficult relationship with Philosophy is well known and has, to some extent, carried over into later work in the field, which tends to view ideas of a philosophical provenance with some suspicion. Nowhere is this more apparent than with ‘archetype’ and the perceived problems with the Kantian noumenal with which it is felt to be inevitably connected. My concern is that such suspicion is rarely psychological, that is, it does not take into consideration enough the psychological aspects and roles of such putatively questionable philosophical ideas. This is another aspect of not really appreciating the psychological aspects of some philosophy due to the illusion of disparity created by what often amounts to a difference of vocabulary rather than of fundamental concerns. I will examine some of the central Kantian concepts that I believe are fundamentally psychological and essential if we are to retain concerns that distinguish Analytical Psychology from related disciplines. We may feel a scientific or philosophical embarrassment when faced with ideas such as ‘noumena’ but my feeling is that, psychologically, there is little to be embarrassed about: such ideas are extremely important in giving some substance to defining concepts of the field of Analytical Psychology.
Tier‐based pricing for institutions: a new, e‐based pricing model
Authors: CHESLER Adam , KING Susan
Published: July 2012

The American Chemical Society (ACS) recently introduced a new pricing model for the digital versions of its journals. Our primary goals were to completely decouple electronic and print subscriptions, to broaden access to content globally, and to address the needs of different market segments so that similar institutions were charged equivalent amounts for comparable usage/need of ACS journals. A cross‐departmental team, with the assistance of independent consultants, analyzed multiple layers of customer data before the new model was built. As a result, we have implemented a two‐faceted model that separately addresses academic and non‐academic subscribers, and that also enables us to assess the relative value of each journal within our portfolio. The process started in 2005 and took over two years to complete, involving numerous staff members and incorporating input from customers worldwide across all market sectors, as well as subscription agents. The model was announced in spring 2007, and applied to 2008 subscriptions. The lessons learned are applicable to any publisher considering a review of its pricing model.
Local structure and p–d hybridization of Mn-doped In2O3 films
Authors: An Yukai , Feng Deqiang , Duan Lingshen , Wu Zhonghua , Liu Jiwen
Published: July 2012

Mn-doped In2O3 films were deposited on Si (1 0 0) substrates by the RF-magnetron sputtering technique. The influence of Mn-doping concentration on the local structure and degree of p–d hybridization was investigated by x-ray absorption spectroscopy at the Mn K-edge and L2,3-edge. The results show that Mn ions dissolve in In2O3 and substitute for In3+ sites in the +2 valence states. With the increase in Mn-doping concentration, the Mn–O bonding distance increases monotonically, but integrated intensities of L2,3 edges increase first and then decrease. It can be concluded that there exists an optimal Mn–O bonding distance for the transition probabilities from the 2p state to the p–d hybridization state, which results in increasing degree of p–d hybridization. So the Mn-doping concentration has a significant effect on the local structure and degree of p–d hybridization in Mn-doped In2O3 films.
Role of singular layers in the plasma response to resonant magnetic perturbations
Authors: Waelbroeck F.L. , Joseph I. , Nardon E. , Bécoulet M. , Fitzpatrick R.
Published: July 2012

The response of an H-mode plasma to magnetic perturbations that are resonant in the edge is evaluated using a fluid model. With two exceptions, the plasma rotation suppresses the formation of magnetic islands, holding their widths to less than a tenth of those predicted by the vacuum approximation. The two exceptions are at the foot of the pedestal, where the plasma becomes more resistive, and at the surface where the perpendicular component of the electron velocity reverses. The perturbations exert a force on the plasma so as to brake the perpendicular component of the electron rotation. In the pedestal, the corresponding Maxwell stress drives the radial electric field in such a way as to accelerate ion rotation. Despite the suppression of the islands, the perturbations give rise to particle fluxes caused by magnetic flutter, with a negligible contribution from E × B convection. In the pedestal, the fluxes are such as to reduce the density.