bluuebunny/crossref_metadata_2025 huggingface dataset:
The Australian fruit Illawarra plum (Podocarpus elatusEndl., Podocarpaceae) inhibits telomerase, increases histone deacetylase activity and decreases proliferation of colon cancer cells
Authors: Symonds Erin L. , Konczak Izabela , Fenech Michael
Published: October 2012

Fruit antioxidants have many health benefits including prevention of cancer development. The native Australian bush fruit Illawarra plum (Podocarpus elatusEndl., Podocarpaceae) has a high content of anthocyanin-rich phenolics, with an antioxidant capacity at levels higher than most fruits. In the present study the molecular mechanisms of the anti-proliferative activity of Illawarra plum on colorectal cancer cells were investigated. Non-tumorigenic young adult mouse colonic (YAMC) cells and tumorigenic human colonic (HT-29) cells were treated with a polyphenolic-rich Illawarra plum extract (0–1000 μg/ml). Illawarra plum had anti-proliferative properties in only the cancer cells, with growth suppressed in a dose- and time-dependent manner. Treatment of HT-29 cells with Illawarra plum extract (500 μg/ml; 24 h) was also associated with a 2-fold increase in apoptosis, and a cell cycle delay in the S phase (P< 0·01). Assessment of biomarkers for DNA damage revealed that plum treatment caused a 93 % down-regulation of telomerase activity (P< 0·001) and a decrease in telomere length (up to 75 %;P< 0·01). Treatment with Illawarra plum extract also induced morphological alterations to HT-29 cells that were suggestive of induction of autophagy, as the formation of cytoplasmic vacuoles was observed in many cells. This could be induced by the increased (6-fold) histone deacetylase (HDAC) activity (P< 0·001) and the trend for increased expression of the class III HDAC sirtuin 1. The present study has shown that Illawarra plum extract is able to reduce the proliferation of colon cancer cells by altering the cell cycle, increasing apoptosis and possibly inducing autophagy. The active ingredients in Illawarra plum may provide an alternative chemoprevention strategy to conventional chemotherapy.
Manipulative parasites may not alter intermediate host distribution but still enhance their transmission: field evidence for increased vulnerability to definitive hosts and non-host predator avoidance
Authors: LAGRUE C. , GÜVENATAM A. , BOLLACHE L.
Published: October 2012

Behavioural alterations induced by parasites in their intermediate hosts can spatially structure host populations, possibly resulting in enhanced trophic transmission to definitive hosts. However, such alterations may also increase intermediate host vulnerability to non-host predators. Parasite-induced behavioural alterations may thus vary between parasite species and depend on each parasite definitive host species. We studied the influence of infection with 2 acanthocephalan parasites (Echinorhynchus truttae and Polymorphus minutus) on the distribution of the amphipod Gammarus pulex in the field. Predator presence or absence and predator species, whether suitable definitive host or dead-end predator, had no effect on the micro-distribution of infected or uninfected G. pulex amphipods. Although neither parasite species seem to influence intermediate host distribution, E. truttae infected G. pulex were still significantly more vulnerable to predation by fish (Cottus gobio), the parasite's definitive hosts. In contrast, G. pulex infected with P. minutus, a bird acanthocephalan, did not suffer from increased predation by C. gobio, a predator unsuitable as host for P. minutus. These results suggest that effects of behavioural changes associated with parasite infections might not be detectable until intermediate hosts actually come in contact with predators. However, parasite-induced changes in host spatial distribution may still be adaptive if they drive hosts into areas of high transmission probabilities.
Fast Real-Time PCR assay for detection of Tetramicra brevifilum in cultured turbot
Authors: ALONSO MERCEDES , LAGO FÁTIMA C. , GÓMEZ-REINO MARÍA , FERNÁNDEZ JACOBO , MARTÍN IRIS , VIEITES JUAN M. , ESPIÑEIRA MONTSERRAT
Published: October 2012

Global aquaculture production of turbot has rapidly increased worldwide in the last decade and it is expected to have even bigger growth in the next years due to new farms operating. The losses caused by pathogen infections have grown at the same time as the production of this species. Parasitological infections are among the main relevant pathologies associated with its culture and produce serious losses in aquaculture, reduce the growth rate in fish and may lead to unmarketable fish due to skeletal muscle abnormalities in cases with high intensity of infection. The microsporidian parasite Tetramicra brevifilum causes severe infections and generates major losses in farmed turbot. Infections are difficult to control due to spore longevity and its direct transmission. To facilitate the infection management, an effective tool for fast detection and identification of T. brevifilum is needed. This study provides a molecular methodology of fast Real-Time PCR for T. brevifilum detection to the aquaculture industry, useful for routine control of T. brevifilum at turbot farms. The method is characterized by its high specificity and sensitivity, and it can be applied to cultured turbot for parasite detection regardless of the life-cycle stage of the pathogen or the infection intensity.
Physical capability and the advantages and disadvantages of ageing: perceptions of older age by men and women in two British cohorts
Authors: PARSONS SAMANTHA , GALE CATHARINE R. , KUH DIANA , ELLIOTT JANE ,   THE HALCYON STUDY TEAM
Published: October 2012

In an increasingly ageing society, its older members are receiving considerable political and policy attention. However, much remains to be learnt about public perceptions ofolderage, particularly the views and experiences of older individuals themselves. Drawing on qualitative interviews carried out with members of two British cohorts (N = 60) who have reached the ‘third age’, this paper discusses perceptions of age, focusing particularly on how perceived advantages and disadvantages differ by respondents' self-reported physical capability. The interviews were carried out in 2010 as part of the HALCyon (Healthy Ageing across the Life Course) collaborative research programme. Findings suggest there is some difference in the way older people view aspects of ageing by capability and that although advantages are widely perceived, physical decline and associated health concerns were the overwhelming theme across the conversations. The article concludes by making tentative suggestions to inform the positive ageing agenda and its related policies.
Association of a functional variant of the nitric oxide synthase 1 gene with personality, anxiety, and depressiveness
Authors: Kurrikoff Triin , Lesch Klaus-Peter , Kiive Evelyn , Konstabel Kenn , Herterich Sabine , Veidebaum Toomas , Reif Andreas , Harro Jaanus
Published: October 2012

A functional promoter polymorphism of the nitric oxide synthase 1 gene first exon 1f variable number tandem repeat (NOS1ex1f-VNTR) is associated with impulsivity and related psychopathology. Facets of impulsivity are strongly associated with personality traits; maladaptive impulsivity with neuroticism; and adaptive impulsivity with extraversion. Both high neuroticism and low extraversion predict anxiety and depressive symptoms. The aim of the present study was to evaluate the effect of theNOS1ex1f-VNTR genotype and possible interaction with environmental factors on personality, anxiety, and depressiveness in a population-representative sample. Short allele carriers had higher neuroticism and anxiety than individuals with the long/long (l/l) genotype. Male short/short homozygotes also had higher extraversion. In the face of environmental adversity, females with a short allele had higher scores of neuroticism, anxiety, and depressiveness compared to the l/l genotype. Males were more sensitive to environmental conditions when they had the l/l genotype and low extraversion. In conclusion, theNOS1ex1f-VNTR influences personality and emotional regulation dependent on gender and environment. Together with previous findings on the effect of theNOS1genotype on impulse control, these data suggest thatNOS1should be considered another plasticity gene, because its variants are associated with different coping strategies.
The implications of genotype–environment correlation for establishing causal processes in psychopathology
Authors: Jaffee Sara R. , Price Thomas S.
Published: October 2012

The significance of genotype–environment interplay is its focus on how causal factors, whether environmental or genetic, have their effects. It is difficult to establish causality in observational research because of the potential for reverse causation and confounding. Most environmental measures are heritable, which means that their effects on the risk for psychopathology are potentially confounded by genotype. In contrast, genetic influences on psychopathology may be mediated by their effect on environmental exposures. The existence of genetic influences on putative environmental risk factors offers both possibilities and pitfalls for research into environmental epidemiology. We use the example of parenting and its influence on childhood externalizing problems to review how genotype–environment correlations can be exploited to demonstrate causal processes in pyschopathology.
Interparental conflict, parent psychopathology, hostile parenting, and child antisocial behavior: Examining the role of maternal versus paternal influences using a novel genetically sensitive research design
Authors: Harold Gordon T. , Elam Kit K. , Lewis Gemma , Rice Frances , Thapar Anita
Published: October 2012

Past research has linked interparental conflict, parent psychopathology, hostile parenting, and externalizing behavior problems in childhood. However, few studies have examined these relationships while simultaneously allowing the contribution of common genetic factors underlying associations between family- and parent-level variables on child psychopathology to be controlled. Using the attributes of a genetically sensitive in vitro fertilization research design, the present study examined associations among interparental conflict, parents' antisocial behavior problems, parents' anxiety symptoms, and hostile parenting on children's antisocial behavior problems among genetically related and genetically unrelated mother–child and father–child groupings. Path analyses revealed that for genetically related mothers, interparental conflict and maternal antisocial behavior indirectly influenced child antisocial behavior through mother-to-child hostility. For genetically unrelated mothers, effects were apparent only for maternal antisocial behavior on child antisocial behavior through mother-to-child hostility. For both genetically related and genetically unrelated fathers and children, interparental conflict and paternal antisocial behavior influenced child antisocial behavior through father-to-child hostility. Effects of parental anxiety symptoms on child antisocial behavior were apparent only for genetically related mothers and children. Results are discussed with respect to the relative role of passive genotype–environment correlation as a possible confounding factor underlying family process influences on childhood psychopathology.
Resilience and measured gene–environment interactions
Authors: Kim-Cohen Julia , Turkewitz Rebecca
Published: October 2012

The past decade has witnessed an exponential growth in studies that have attempted to identify the genetic polymporphisms that moderate the influence of environmental risks on mental disorders. What tends to be neglected in these Gene × Environment (G × E) interaction studies has been a focus on resilience, which refers to a dynamic pattern of positive adaptation despite the experience of a significant trauma or adversity. In this article, we argue that one step toward advancing the field of developmental psychopathology would be for G × E research to consider resilience instead of focusing almost exclusively on mental disorders. After providing an up-to-date summary on the expanding definitions and models of resilience, and the available evidence regarding measured G × E studies of childhood maltreatment, we discuss why resilience would be a worthwhile phenotype for studies of measured G × E. First, although G × E hypotheses require that there be an environmental risk (e-risk) involved in a causal process that leads to psychopathology, e-risks are typically not included in the diagnostic criteria for most psychiatric disorders. In contrast, resilience by definition includes an e-risk. Second, G × E hypotheses require that there is evidence of variability in response to an environmental stressor, and resilience often represents the positive end on this continuum of adaptation. Third, both resilience and G × E are best understood from a developmental perspective. Fourth, although resilient outcomes are not public health concerns, the types of adversities (e.g., childhood maltreatment, poverty, or exposure to natural disasters) that are often investigated in studies of resilience certainly are. Understanding how some individuals, perhaps because of their genetic makeup, are able to withstand such adversities can inform prevention and intervention efforts to improve mental health.
The gene in its natural habitat: The importance of gene–trait interactions
Authors: DeYoung Colin G. , Clark Rachel
Published: October 2012

Despite the substantial heritability of nearly all psychological traits, it has been difficult to identify specific genetic variants that account for more than a tiny percentage of genetic variance in phenotypes. Common explanations for this “missing heritability” include massive polygenicity, rare variants, epigenetics, epistasis, and gene–environment interactions. Gene–trait (G × T) interaction is another concept useful for understanding the lack of obvious genetic main effects. Both genes and environments are distal contributors to human behavior, but the brain is the proximal driver of behavior. The effect of any single genetic variant is dependent on the configuration of the brain in which it is expressed. One method to begin studying how single genes interact with variations in the rest of the brain is to investigate G × T interactions. A psychological trait reflects a characteristic pattern of psychological function (and, therefore, of brain function), which has its origin in the cumulative effects of both the genome and the environment. A trait therefore describes variation in the broad organismic context in which any single gene operates. We describe the nature and significance of G × T interactions for understanding psychopathology and normal trait variation, which are illustrated with empirical examples.
Genomic structural variation in psychiatric disorders
Authors: Rucker James J. H. , McGuffin Peter
Published: October 2012

Copy number variants (CNVs) are submicroscopic deletions and duplications of genomic material that were previously thought to be rare phenomena. They have now been robustly associated with a variety of disorders such as autism, schizophrenia, and attention-deficit/hyperactivity disorder through an emerging research base in affective disorders. A complex picture is emerging of a polygenic, heterogeneous model of disease, with CNVs conferring broad susceptibility to a variety of neurodevelopmental disorders, rather than specific disorders per se. Although the insights gleaned thus far only represent a small piece of a much larger puzzle, progress has been rapid and new technologies promise even more insights into these hitherto opaque brain disorders. We will discuss CNVs, the current state of evidence for their role in the pathogenesis of classical psychiatric disorders, and the application of such knowledge in clinical settings.
Lexical decision as an endophenotype for reading comprehension: An exploration of an association
Authors: Naples Adam , Katz Len , Grigorenko Elena L.
Published: October 2012

Based on numerous suggestions in the literature, we evaluated lexical decision (LD) as a putative endophenotype for reading comprehension by investigating heritability estimates and segregation analyses parameter estimates for both of these phenotypes. Specifically, in a segregation analysis of a large sample of families, we established that there is little to no overlap between genes contributing to LD and reading comprehension and that the genetic mechanism behind LD derived from this analysis appears to be more complex than that for reading comprehension. We conclude that in our sample, LD is not a good candidate as an endophenotype for reading comprehension, despite previous suggestions from the literature. Based on this conclusion, we discuss the role and benefit of the endophenotype approach in studies of complex human cognitive functions.
Neurobiology meets genomic science: The promise of human-induced pluripotent stem cells
Authors: Stevens Hanna E. , Mariani Jessica , Coppola Gianfilippo , Vaccarino Flora M.
Published: October 2012

The recent introduction of the induced pluripotent stem cell technology has made possible the derivation of neuronal cells from somatic cells obtained from human individuals. This in turn has opened new areas of investigation that can potentially bridge the gap between neuroscience and psychopathology. For the first time we can study the cell biology and genetics of neurons derived from any individual. Furthermore, by recapitulating in vitro the developmental steps whereby stem cells give rise to neuronal cells, we can now hope to understand factors that control typical and atypical development. We can begin to explore how human genes and their variants are transcribed into messenger RNAs within developing neurons and how these gene transcripts control the biology of developing cells. Thus, human-induced pluripotent stem cells have the potential to uncover not only what aspects of development are uniquely human but also variations in the series of events necessary for normal human brain development that predispose to psychopathology.
Ultrastructural and Biochemical Alterations in Rats Exposed to Crude Extract of Carex baccans and Potentilla fulgens
Authors: Roy Bishnupada , Giri Bikash Ranjan , Chetia Mitali , Swargiary Ananta
Published: October 2012

The use of plants as a source of medicine is an important component of the health care system in rural India. Carex baccans (Cyperaceae) and Potentilla fulgens (Rosaceae) have been known since ancient times in northeast India for their antitumor, antidiabetic, and antihelmintic properties. The present study was designed to determine the subacute toxicity profile of the root tuber extract of C. baccans and root-peel extract of P. fulgens in Wistar rats. The subacute oral toxicity was conducted using sublethal doses of 40, 50, 100, 150, 200, and 400 mgkg−1 body weights. Surface topographical and ultrastructural observations of liver and intestinal microvilli showed remarkable deformation and disruption, accompanied by quantitative changes in the liver enzymes, i.e., aspartate aminotransferase and alanine aminotransferase in comparison to those of the control group. Apoptotic cell death was observed in the liver cells of rats exposed to both of the plant extracts. A significant increase in splenic lymphocyte count was also observed in rats exposed to the highest concentration of both extracts. The results showed that consumption of the plant extracts at higher doses may cause toxicological effect if treatment continues for a long time.
Behind Closed Doors: Older Couples and the Gendered Management of Household Money
Authors: Bisdee Dinah , Daly Tom , Price Debora
Published: October 2012

As couples survive longer and live together into older age they face many issues of financial management, including daily money management on reduced and/or reducing income, and paying for care or the additional costs of disability. Yet household money management is highly gendered, especially for older age groups. This has implications for the ability of women, particularly, to manage financial decisions in the face of their partner's illness, or widowhood, as well as for their autonomy and well-being. We analyse in depth qualitative data from forty-five older couples across the socio-economic spectrum to show that women have varying emotional responses to money management in coupledom: ‘accepters’ who accept financial inequality and dominance by their husbands, ‘resenters’ who recognise these inequalities but resent them, and ‘modifiers/resisters’ who retain financial independence and power within their relationships. It is only the latter group, who have long histories of financial control and management, who are well placed for financial management and decisions in later life. By recognising the implications of different types of couple relationship, policies can be better designed to assist those navigating money in later life.
An Update on the Florida State Twin Registry
Authors: Taylor Jeanette E. , Hart Sara A. , Mikolajewski Amy J. , Schatschneider Christopher
Published: October 2012

The Florida State Twin Registry began in 2002 through a pilot study of personality disorders and executive cognitive functioning in adult twins. Since 2006, the registry has grown substantially as part of the Learning Disability Research Center at Florida State University that recently began its second funding cycle through the National Institute of Child Health and Development. An update on the Florida State Twin Registry sample, focus, and measures is provided, as well as future directions.
Geodetic imaging: A new tool for Mesoamerican archaeology
Authors: Carter William E. , Shrestha Ramesh L. , Fisher Christopher , Leisz Stephen
Published: October 2012

On 15 May 2012, Honduran President Porfirio Lobo convened a press conference to announce that researchers mapping areas of the Mosquitia region of Honduras, using airborne light detection and ranging (lidar), had discovered what appeared to be an extensive complex of archaeological ruins hidden beneath the dense canopy of rain forest that shrouds the terrain [UTL Scientific, LLC, 2012]. President Lobo released preliminary images of the ruins derived from the airborne lidar observations (Figure 1a) but withheld information about their precise location so that measures could be taken to protect and preserve this newly discovered cultural heritage. The coordinates of the ruins, determined from the lidar observations with an accuracy of a few decimeters, will enable archaeological teams to use the Global Positioning System to navigate through the dense forest directly to features of interest.
Law addresses question of space artifact ownership
Authors: Showstack Randy
Published: October 2012

U.S. astronauts who participated in many of NASA's early space missions will receive full ownership rights to artifacts from those missions through legislation that President Barack Obama signed into law on 25 September. The legislation, which received broad bipartisan support, provides artifact ownership rights to any of NASA's Mercury, Gemini, or Apollo space programs through the completion of the Apollo‐Soyuz Test Project, whose flight occurred in July 1975. The law defines artifacts as expendable, disposable, or personal use items—including personal logs and flight hardware salvaged from jettisoned lunar modules—used by astronauts that were not required to be returned to NASA; lunar rocks and other lunar material are not defined as artifacts. Bill cosponsor Rep. Ralph Hall (R‐Tex.), chair of the House of Representatives' Committee on Science, Space, and Technology, said on 19 September, “A majority of these items have been in the personal possession of the astronauts for 40 years or more. Over the last decade, NASA has begun to challenge the astronauts' ownership of these mementos. This issue was first brought to my attention late last year. I was surprised to learn that NASA had, on an irregular basis, intervened several times to claim ownership.”
Understanding origins and impacts of drought
Authors: Loboda Tatiana , Krankina Olga , Kurbanov Eldar
Published: October 2012

Impacts of Extreme Weather on Natural, Socio‐economic, and Land‐Use Systems:Focus on the 2010 Summer Anomaly in the Volga Region;Yoshkar‐Ola, Russia, 17–21 June 2012 In the summer of 2010 an extreme drought captured the attention of the media, the Russian government, and the international community. This drought resulted in widespread crop failure within one of the largest wheat‐exporting regions of the world, leading to global grain price hikes. A joint NASA, Global Observations of Forest and Land Cover Dynamics (GOFC‐GOLD), and Northern Eurasia Earth Science Partnership Initiative (NEESPI) meeting at the Volga State University of Technology, held 2 years after the 2010 drought, provided for a wide‐ranging and in‐depth review of recent research on the drought and its impacts on ecosystems and society and drew participants from the United States, Europe, Russia, and Kazakhstan.
Climate change threatens permafrost in soil
Authors: Bhattacharya Atreyee
Published: October 2012

In the coming century, permafrost in polar regions and alpine forests in the northern hemisphere may thaw rapidly, potentially releasing carbon and nitrogen that could cause additional regional warming. Permafrost occurs in soils where ground temperatures remain below freezing for at least two consecutive years. These special types of soil, called gelisols, are large reservoirs of organic carbon and nitrogen. Thawing is likely to release the carbon and nitrogen in these soils to rivers and lakes, ecosystems, and the atmosphere; different soil types are vulnerable to different thawing processes.
Trade‐offs between water for food and for curbing climate change
Authors: Balcerak Ernie
Published: October 2012

Earth's growing human population needs fresh water for drinking and food production. However, fresh water is also needed for the growth of biomass, which acts as a sink of carbon dioxide and thus could help mitigate climate change. Does the Earth have enough freshwater resources to meet these competing demands? Rockström et al. estimate the order of magnitude of freshwater consumption needed to feed a population of 9 billion people by 2050 and the amount of water needed to realize the planet's full biomass carbon sequestration potential. The researchers analyze these uses of freshwater in a framework of “planetary boundaries” within which the Earth system is resilient; beyond the boundaries, abrupt and irreversible change could take place. For instance, river ecosystems can collapse if water levels become too low due to water withdrawal for human uses.
Hotter days and droughts to continue through the 21st century
Authors: Bhattacharya Atreyee
Published: October 2012

As heat waves become more frequent and droughts cause famines and drive up food prices, climate policies will need to account for changes in extremes in temperature and precipitation, as global mean temperatures continue to rise through the 21st century. Using HadGEM2, a new ocean‐atmosphere coupled climate model, Caesar and Lowe investigated the effects of different greenhouse gas emissions scenarios on maximum and minimum air temperatures as well as on the amounts of rainfall in different parts of the world. The authors compared two scenarios through the 21st century, the first one with an aggressive mitigation scenario, in which global emissions begin to decrease in the early 21st century and reach nearly zero by 2100; the second scenario had no mitigation. The researchers' results show that extreme temperatures would scale with increasing mean temperature, at least until the middle of the 21st century: As air temperatures increase, countries across the globe would experience hotter days and an increasing number of heat waves, even with aggressive mitigation. However, mitigation may provide some amelioration, particularly through the second half of the 21st century; the northern midlatitudes would benefit most from mitigation measures, although northern South America and parts of the United States, Africa, and Asia could also avoid large increases in extreme temperature maxima by following similar mitigation policies.
The Everglades are still threatened by excess nutrients
Authors: Bhattacharya Atreyee
Published: October 2012

Since 1985, a Florida state agency constructed and maintained hundreds of square kilometers of wetlands built to regulate the amount of nutrients reaching the Everglades in southern Florida. However, Zapata‐Rios et al. show that this is proving to be ineffective in controlling concentrations of phosphorous, a key nutrient, in the surface waters of the wetland. Historically, the Everglades has been a nutrient‐poor environment, a characteristic that determines the delicate ecological balance and distinct flora and fauna in this region. Agricultural development and urbanization since the 1800s have not only claimed two‐ thirds of the natural Everglades (only 6000 square kilometers now exist in their natural form) but have also dramatically increased phosphorus levels in surface water, at times exceeding the acceptable limit of 10 micrograms per liter by severalfold.
Remote monitoring of sediment load in ocean water
Authors: Bhattacharya Atreyee
Published: October 2012

Using the Geostationary Ocean Color Imager (GOCI)—the world's first geostationary satellite sensor that can obtain observational data on ocean color every hour during the daytime—scientists are able to remotely monitor the amount of suspended sediment, organic activity, pollutants, and almost any parameter that affects the turbidity and hence the color of the surface of the ocean, in near–real time. Choi et al. compared GOCI images with measurements of suspended sediment load in the Mokpo coastal area along the west coast of Korea. They show that the GOCI color images can reliably monitor suspended sediment load in these coastal waters. They also found that the sediment movement in this region is driven primarily by daily tidal cycles.
Detecting hidden volcanic explosions from Mt. Cleveland Volcano, Alaska with infrasound and ground‐coupled airwaves
Authors: De Angelis Silvio , Fee David , Haney Matthew , Schneider David
Published: October 2012

In Alaska, where many active volcanoes exist without ground‐based instrumentation, the use of techniques suitable for distant monitoring is pivotal. In this study we report regional‐scale seismic and infrasound observations of volcanic activity at Mt. Cleveland between December 2011 and August 2012. During this period, twenty explosions were detected by infrasound sensors as far away as 1827 km from the active vent, and ground‐coupled acoustic waves were recorded at seismic stations across the Aleutian Arc. Several events resulting from the explosive disruption of small lava domes within the summit crater were confirmed by analysis of satellite remote sensing data. However, many explosions eluded initial, automated, analyses of satellite data due to poor weather conditions. Infrasound and seismic monitoring provided effective means for detecting these hidden events. We present results from the implementation of automatic infrasound and seismo‐acoustic eruption detection algorithms, and review the challenges of real‐time volcano monitoring operations in remote regions. We also model acoustic propagation in the Northern Pacific, showing how tropospheric ducting effects allow infrasound to travel long distances across the Aleutian Arc. The successful results of our investigation provide motivation for expanded efforts in infrasound monitoring across the Aleutians and contributes to our knowledge of the number and style of vulcanian eruptions at Mt. Cleveland.
A statistical analysis of the association between fast plasma flows and Pi2 pulsations
Authors: Hsu Tung‐Shin , McPherron R. L. , Angelopoulos Vassilis , Ge Yasong , Zhang Hui , Russell Christopher , Chu Xiangning , Kissinger Jennifer
Published: October 2012

What is the energy source for Pi2 pulsations? Some researchers have suggested that Pi2 pulsations are caused by plasma flows. Others have suggested that Pi2s are caused by a plasma instability initiated in the near‐Earth region. In this study we use Time History of Events and Macroscale Interactions during Substorms (THEMIS) data to examine the relationship between plasma flows and Pi2s. We first identify plasma flows in the tail and then associate these flows with Pi2s. We find that the overall probability of association is nearly 70%. If we further examine the spatial distribution of association we find that in the near‐Earth region (8–15RE) 90% of the flows are associated with Pi2s. This suggests either that plasma flow in the tail is the cause of Pi2 on the ground or that both are caused by the same process. More importantly, as the flows approach the Earth, the increasing magnetic field causes the flow speed to decrease, that is, the flows are decelerated. In this process of flow braking, the local magnetic field becomes more dipolar. The region of strongest flow braking corresponds to the region of strongest association between flows and Pi2s (8–15 RE). The GSM X component of plasma flows become zero at around 8 RE where the most significant magnetic dipolarization occurs. We also find that most plasma flows are associated with a sudden enhancement of the westward electrojet. These results suggest that plasma flows, Pi2 pulsations, and magnetic field dipolarization are essential components of the substorm expansion onset.
A three‐dimensional seismic wave speed model in southwestern Japan from combined use of waveform modeling and travel‐time tomography
Authors: Hayashida Takumi , Tajima Fumiko , Nakajima Junichi , Mori Jim
Published: October 2012

Recent three‐dimensional (3‐D) travel‐time tomographic models of southwestern (SW) Japan image the subducting Philippine Sea plate (PHSP) and low velocity anomalies with long‐wavelength spatial resolution. However, the agreement between the synthetics calculated with the existing 3‐D model and data is not satisfactory forsP and S waves in the higher frequency range (≥0.2 Hz). The unsatisfactory agreement can be attributed to the parameters of the initial wave speed model for the tomographic inversion, as well as the difficulty in detecting S‐wave travel times accurately. In order to improve the wave speed model, we first constructed a 3‐D reference model by forward modeling using waveform data from an intraslab earthquake and then performed repeated travel‐time inversions using the 3‐D reference model as the initial model. The newly derived high‐resolution model 3DM_SWJ can produce synthetics that are substantially in better agreement with the data than previous models. The distribution of highP‐wave toS‐wave speed ratios (VP/VS) calculated from model 3DM_SWJ shows short‐wavelength heterogeneities that could have been formed in relation to the subduction of the Philippine Sea Plate beneath the Eurasian plate. This combined use of forward waveform modeling for slab and crust configuration and repeated tomographic inversion of travel‐times provides a better 3‐D structural model of seismic properties for understanding tectonic features related to the subduction process, in addition to better estimating ground motions.
Rapid Nipah virus entry into the central nervous system of hamsters via the olfactory route
Authors: Munster Vincent J. , Prescott Joseph B. , Bushmaker Trenton , Long Dan , Rosenke Rebecca , Thomas Tina , Scott Dana , Fischer Elizabeth R. , Feldmann Heinz , de Wit Emmie
Published: October 2012

Encephalitis is a hallmark of Nipah virus (NiV) infection in humans. The exact route of entry of NiV into the central nervous system (CNS) is unknown. Here, we performed a spatio-temporal analysis of NiV entry into the CNS of hamsters. NiV initially predominantly targeted the olfactory epithelium in the nasal turbinates. From there, NiV infected neurons were visible extending through the cribriform plate into the olfactory bulb, providing direct evidence of rapid CNS entry. Subsequently, NiV disseminated to the olfactory tubercle and throughout the ventral cortex. Transmission electron microscopy on brain tissue showed extravasation of plasma cells, neuronal degeneration and nucleocapsid inclusions in affected tissue and axons, providing further evidence for axonal transport of NiV. NiV entry into the CNS coincided with the occurrence of respiratory disease, suggesting that the initial entry of NiV into the CNS occurs simultaneously with, rather than as a result of, systemic virus replication.
Diamondoid coating enables disruptive approach for chemical and magnetic imaging with 10 nm spatial resolution
Authors: Ishiwata Hitoshi , Acremann Yves , Scholl Andreas , Rotenberg Eli , Hellwig Olav , Dobisz Elizabeth , Doran Andrew , Tkachenko Boryslav A. , Fokin Andrey A. , Schreiner Peter R. , Dahl Jeremy E. P. , Carlson Robert M. K. , Melosh Nick , Shen Zhi-Xun , Ohldag Hendrik
Published: October 2012

Diamondoids are unique molecular nano-materials with diamond structure and fascinating properties such as negative electron affinity and short electron mean free paths. A thin layer of diamondoids deposited on a cathode is able to act as an electron monochromator, reducing the energy spread of photo-emitted electrons from a surface. This property can be applied effectively to improve the spatial resolution in x-ray photoemission electron microscopy (X-PEEM), which is limited by chromatic aberration of the electron optics. In this paper, we present X-PEEM measurements reaching the technological relevant spatial resolution of 10 nm without the need of expensive and complex corrective optics. Our results provide a simple approach to image surface chemical and magnetic information at nanometer scales by employing diamondoids.
Photoresponsivity enhancement of pentacene organic phototransistors by introducing C60 buffer layer under source/drain electrodes
Authors: Yao Bo , Lv Wenli , Chen Deqiang , Fan Guoying , Zhou Maoqing , Peng Yingquan
Published: October 2012

Pentacene organic phototransistors (OPTs) modified by introducing C60 electrodes buffer layer were fabricated. Compared with conventional single-layer pentacene OPTs, the devices with C60 buffer layer exhibited higher performance under illumination. Maximum photoresponsivity is 4.27 A/W at zero gate bias under 0.2 mW cm−2, which is six times higher than that of single-layer device and exceeds that of most OPTs reported recently in the same conditions. The maximum photo/dark current ratio is also higher than 5 × 104. Meanwhile, the C60 modified device could obtain lower threshold voltage and higher field-effect mobility. These results suggest that single-layer OPTs modified by heterojunction buffer layer will obtain better optical response.
Deformable homeotropic nematic droplets in a magnetic field
Authors: Otten Ronald H. J. , van der Schoot Paul
Published: October 2012

We present a Frank-Oseen elasticity theory for the shape and structure of deformable nematic droplets with homeotropic surface anchoring in the presence of a magnetic field. Inspired by recent experimental observations, we focus on the case where the magnetic susceptibility is negative, and find that small drops have a lens shape with a homogeneous director field for any magnetic-field strength, whereas larger drops are spherical and have a radial director field, at least if the magnetic field is weak. For strong magnetic fields the hedgehog configuration transforms into a split-core line defect that, depending on the anchoring strength, can be accompanied by an elongation of the tactoid itself. We present a three-dimensional phase diagram that shows the tactoid shape and director field for a given anchoring strength, tactoid size, and magnetic-field strength. Our findings rationalize the different shapes and structures that recently have been observed experimentally for nematic droplets found in dispersions of gibbsite platelets in two types of solvent.
Eddy current effects in plain and hollow cylinders spinning inside homogeneous magnetic fields: Application to magnetic resonance
Authors: Aubert G. , Jacquinot J.-F. , Sakellariou D.
Published: October 2012

We present a thorough analysis of eddy currents that develop in a rectangular cross section toroid rotating in a uniform magnetic field. The slow rotation regime is assumed. Compact expressions for the current density, the total dissipated power, and the braking torque are given. Examination of the topology of current lines reveals that depending upon the relative dimensions of the side and length of the toroid two different regimes exist. The conditions of existence of the two regimes are analytically established. In view of nuclear magnetic resonance (NMR) applications, we derive the angular variation of the magnetic field created by eddy currents and lay down the formalism necessary for calculating the effect of this field on the NMR spectra of the conductor itself or of a sample co-rotating with the conductor, a situation encountered when dealing with rotating detectors. Examples of calculations for cases of practical interest are presented. The theory is confronted with available data, and we give guidelines for the design of optimized rotating micro-coils.
Decoherence-induced surface hopping
Authors: Jaeger Heather M. , Fischer Sean , Prezhdo Oleg V.
Published: October 2012

A simple surface hopping method for nonadiabatic molecular dynamics is developed. The method derives from a stochastic modeling of the time-dependent Schrödinger and master equations for open systems and accounts simultaneously for quantum mechanical branching in the otherwise classical (nuclear) degrees of freedom and loss of coherence within the quantum (electronic) subsystem due to coupling to nuclei. Electronic dynamics in the Hilbert space takes the form of a unitary evolution, intermittent with stochastic decoherence events that are manifested as a localization toward (adiabatic) basis states. Classical particles evolve along a single potential energy surface and can switch surfaces only at the decoherence events. Thus, decoherence provides physical justification of surface hopping, obviating the need for ad hoc surface hopping rules. The method is tested with model problems, showing good agreement with the exact quantum mechanical results and providing an improvement over the most popular surface hopping technique. The method is implemented within real-time time-dependent density functional theory formulated in the Kohn-Sham representation and is applied to carbon nanotubes and graphene nanoribbons. The calculated time scales of non-radiative quenching of luminescence in these systems agree with the experimental data and earlier calculations.
Relativistic diffusion Monte Carlo method: Zeroth-order regular approximation-diffusion Monte Carlo method in a spin-free formalism
Authors: Nakatsuka Yutaka , Nakajima Takahito
Published: October 2012

A diffusion Monte Carlo (DMC) method for the relativistic zeroth-order regular approximation (ZORA) is proposed. In this scheme, a novel approximate Green's function is derived for the spin-free ZORA Hamiltonian. Several numerical tests on atoms and small molecules showed that by combining with the relativistic cusp-correction scheme, the present approach can include both relativistic and electron-correlation effects simultaneously. The correlation energies recovered by the ZORA-DMC method are comparable with the nonrelativistic DMC results and superior to the coupled cluster singles and doubles with perturbative triples correction results when the correlation-consistent polarized valence triple-zeta Douglas–Kroll basis set is used. For the heavier CuH molecule, the ZORA-DMC estimation of its dissociation energy agrees with the experimental value within the error bar.
Video-based and interference-free axial force detection and analysis for optical tweezers
Authors: Knust Sebastian , Spiering Andre , Vieker Henning , Beyer André , Gölzhäuser Armin , Tönsing Katja , Sischka Andy , Anselmetti Dario
Published: October 2012

For measuring the minute forces exerted on single molecules during controlled translocation through nanopores with sub-piconewton precision, we have developed a video-based axial force detection and analysis system for optical tweezers. Since our detection system is equipped with a standard and versatile CCD video camera with a limited bandwidth offering operation at moderate light illumination with minimal sample heating, we integrated Allan variance analysis for trap stiffness calibration. Upon manipulating a microbead in the vicinity of a weakly reflecting surface with simultaneous axial force detection, interference effects have to be considered and minimized. We measured and analyzed the backscattering light properties of polystyrene and silica microbeads with different diameters and propose distinct and optimized experimental configurations (microbead material and diameter) for minimal light backscattering and virtually interference-free microbead position detection. As a proof of principle, we investigated the nanopore threading forces of a single dsDNA strand attached to a microbead with an overall force resolution of ±0.5 pN at a sample rate of 123 Hz.
Perspective: Nonadiabatic dynamics theory
Authors: Tully John C.
Published: October 2012

Nonadiabatic dynamics—nuclear motion evolving on multiple potential energy surfaces—has captivated the interest of chemists for decades. Exciting advances in experimentation and theory have combined to greatly enhance our understanding of the rates and pathways of nonadiabatic chemical transformations. Nevertheless, there is a growing urgency for further development of theories that are practical and yet capable of reliable predictions, driven by fields such as solar energy, interstellar and atmospheric chemistry, photochemistry, vision, single molecule electronics, radiation damage, and many more. This Perspective examines the most significant theoretical and computational obstacles to achieving this goal, and suggests some possible strategies that may prove fruitful.
In situ cleaning of instruments for the sensitive detection of organics on Mars
Authors: Anderson M. S. , Katz I. , Petkov M. , Blakkolb B. , Mennella J. , D’Agostino S. , Crisp J. , Evans J. , Feldman J. , Limonadi D.
Published: October 2012

A method is presented for in situ cleaning of spacecraft instruments that analyze planetary soil and rock. We have found that vibrating hardware, used to facilitate powder transport, was also effective at removing contamination. Surfaces can be cleaned below monolayer levels using vibrating surfaces in the presence of mineral powder. Both organic and particulate contamination is efficiently removed. Fine grained regolith from the planetary surface or an organic free reference material may serve as the powder used for cleaning. We present both analytical and experimental results for the contamination transfer fraction and the conditions required to clean the hardware prior to sensitive chemical analysis.
Monte Carlo simulation study of spin transport in trilayer graphene: A comparison between ABA and ABC stacking
Authors: Ghosh Bahniman , Misra Soumya
Published: October 2012

In this work, we have used semi-classical Monte Carlo simulations to model spin transport in trilayer graphene (TLG) with ABA as well as ABC stacking. We have taken into consideration both the D'yakonov–Perel (DP) and Elliot–Yafet (EY) mechanisms of spin relaxation for modeling purposes. The two different stacking orders, ABA and ABC, have different band-structures, and we have studied the effect of the change in band structure on spin transport. Further, we have compared these results with bilayer graphene and single layer graphene and tried to explain the differences in the spin relaxation lengths in terms of band structure. We observe that TLG with ABC stacking exhibits a significantly higher spin relaxation length than TLG with ABA stacking.