bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlations between sadness-induced cerebral activations and schizophrenia symptoms: An fMRI study of sex differences
Authors: Mendrek A. , Jiménez J.A. , Mancini-Marïe A. , Fahim C. , Stip E.
Published: July 2010

Background

The functional neuroimaging studies of emotion processing in schizophrenia have revealed variable results attributed partly to differential symptomatology and sex of tested patients. The aim of the present study was to investigate the relationship between cerebral activations during exposure to emotional material and schizophrenia symptoms in men versus women.

Method

Fifteen men and 10 women with schizophrenia, equivalent in terms of age, medication and experienced symptomatology, underwent functional MRI during viewing sad and neutral film excerpts. Data were analyzed using Statistical Parametric Mapping Software (SPM2).

Results

Across all the patients there was a significant inverse relationship between negative symptoms and activations in the right prefrontal cortex during processing of sad versus neutral stimuli. In men, activations during sad versus neutral stimuli in the prefrontal, temporal and anterior cingulate cortex, as well as the caudate and cerebellum, were positively correlated with negative symptoms. In women, there were inverse correlations between positive symptoms and activations in the hippocampus, parietal and occipital cortex during the same condition.

Conclusion

Present results confirmed association of prefrontal hypofunction with negative symptoms in schizophrenia. More interestingly, the results revealed a diametrically different pattern of symptom-correlated brain activity in men and women with schizophrenia, suggesting that the processing of sadness is mediated via neurophysiological mechanism related to negative symptoms in men and the mechanism related to positive symptoms in women.
Do they Actually Work Across Borders? Evaluation of two Measures of Psychological Distress as Screening Instruments in a Non Anglo-Saxon Country
Authors: Carrà G. , Sciarini P. , Segagni-Lusignani G. , Clerici M. , Montomoli C. , Kessler R.C.
Published: July 2010

Screening scales can be useful in searching for common mental disorders in primary care and in tracking relevant prevalence and correlates in community surveys. However, it is important to document their validity, before using them. We developed Italian versions of the widely-used K10 and K6 screening scales following the WHO forward-translation and back-translation protocol. To evaluate their effectiveness as screens for DSM-IV 12-month mood or anxiety disorders and “serious mental illness” (SMI), the scales were validated in a two-stage clinical reappraisal survey. In the first-phase, the scales were administered to 605 people. In the second-phase, a sub-sample of 147 first-phase respondents over-sampling screened positives was administered the 12-month version of the Structured Clinical Interview for DSM-IV Axis I Disorders as a clinical gold standard. Performance of the scales in screening for chosen disorders was assessed by calculating area under the receiver operating characteristic curve and stratum-specific likelihood ratios. Both the K10 and K6 performed well in detecting DSM-IV mood disorders, anxiety disorders, and serious mental illness (SMI), with areas under the curve (AUCs) (95% CIs) between 0.82 (0.75–0.89) and 0.91 (0.85–0.96). The Italian versions of the K6 and K10 scales have good psychometric properties, making them attractive inexpensive screens for mood disorders, anxiety disorders, and SMI.
Brain imaging findings in children and adolescents with mental disorders: A cross-sectional review
Authors: Mana S. , Paillère Martinot M.-L. , Martinot J.-L.
Published: July 2010

Background

While brain imaging studies of juvenile patients has expanded in recent years to investigate the cerebral neurophysiologic correlates of psychiatric disorders, this research field remains scarce. The aim of the present review was to cluster the main mental disorders according to the differential brain location of the imaging findings recently reported in children and adolescents reports. A second objective was to describe the worldwide distribution and the main directions of the recent magnetic resonance imaging (MRI) and positron tomography (PET) studies in these patients.

Methods

A survey of 423 MRI and PET articles published between 2005 and 2008 was performed. A principal component analysis (PCA), then an activation likelihood estimate (ALE) meta-analysis, were applied on brain regional information retrieved from articles in order to cluster the various disorders with respect to the cerebral structures where alterations were reported. Furthermore, descriptive analysis characterized the literature production.

Results

Two hundred and seventy-four articles involving children and adolescent patients were analyzed. Both the PCA and ALE methods clustered, three groups of diagnosed psychiatric disorders, according to the brain structural and functional locations: one group of affective disorders characterized by abnormalities of the frontal-limbic regions; a group of mental disorders with “cognition deficits” mainly related to cortex abnormalities; and one psychomotor condition associated with abnormalities in the basal ganglia. The descriptive analysis indicates a focus on attention deficit hyperactivity disorders and autism spectrum disorders, a general steady rise in the number of annual reports, and lead of US research.

Conclusion

This cross-sectional review of child and adolescent mental disorders based on neuroimaging findings suggests overlaps of brain locations that allow to cluster the diagnosed disorders into three sets with respectively marked affective, cognitive, and psychomotor phenomenology. Furthermore, the brain imaging research effort was unequally distributed across disorders, and did not reflect their prevalence.
The Munich 15-year follow-up study (MUFUSSAD) on first-hospitalized patients with schizophrenic or affective disorders: Assessing courses, types and time stability of diagnostic classification
Authors: Möller H.J. , Jäger M. , Riedel M. , Obermeier M. , Strauss A. , Bottlender R.
Published: July 2010

Objective

In the context of the development of DSM-V and ICD-11 it appears to be useful to get further data on the validity of the diagnostic differentiation between schizophrenic and affective disorders. This study investigated the relevance of the main diagnostic groups schizophrenia, schizoaffective psychosis and affective disorder in the context of different diagnostic systems (ICD-9, ICD-10, DSM –IV), assessing their time stability, long-term courses, types and functional outcome.

Methods

A total of 323 first hospitalized inpatients of the Psychiatric Department of the University Munich were recruited at index time. The full follow-up evaluation including standardized assessment procedures could be performed in 197 patients.

Results

The re-diagnosis of the patients’ disorders shows that with the transition from ICD-9 to ICD-10 or DSM-IV, the group of affective disorders increased numerically while the diagnostic groups of schizophrenia and schizoaffective disorders decreased in size. The structured clinical interview for DSM-IV (SCID) analysis showed that altogether ICD-10 and DSM-IV had a relatively high diagnostic stability. Of the patients with an ICD-10 diagnosis of schizophrenia, 57% had a chronic course; 61% of the patients with a DSM-IV diagnosis of schizophrenia. Patients with affective disorders, according either to ICD-10 or DSM-IV, had in more than 90% of the cases an episodic-remitting course. In terms of prediction of long-term outcome regarding the differentiation between chronic and non-chronic course, the ICD-10 diagnoses did give a slightly better predictive result than a dimensional approach based on the key psychopathological syndrome scores.

Conclusions

The differentiation between schizophrenic and affective disorders seems meaningful especially under predictive aspects. A dimensional syndromatological description does not exceed the predictive power of the investigated main diagnostic categories, but might increase the clinically relevant information.
A prospective longitudinal study of the impact of early postnatal vs. chronic maternal depressive symptoms on child development
Authors: Sutter-Dallay A.-L. , Murray L. , Dequae-Merchadou L. , Glatigny-Dallay E. , Bourgeois M.-L. , Verdoux H.
Published: July 2010

Background

Few studies of the effects of postnatal depression on child development have considered the chronicity of depressive symptoms. We investigated whether early postnatal depressive symptoms (PNDS) predicted child developmental outcome independently of later maternal depressive symptoms.

Methods

In a prospective, longitudinal study, mothers and children were followed-up from birth to 2 years; repeated measures of PNDS were made using the Edinburgh Postnatal Depression Scale (EPDS); child development was assessed using the Bayley Scales II. Multilevel modelling techniques were used to examine the association between 6 week PNDS, and child development, taking subsequent depressive symptoms into account.

Results

Children of mothers with 6 week PNDS were significantly more likely than children of non-symptomatic mothers to have poor cognitive outcome; however, this association was reduced to trend level when adjusted for later maternal depressive symptoms.

Conclusion

Effects of early PNDS on infant development may be partly explained by subsequent depressive symptoms.
Elevation of cyclic AMP causes an imbalance between NF‐κB and p53 in NALM‐6 cells treated by doxorubicin
Authors: Safa Majid , Zand Hamid , Mousavizadeh Kazem , Kazemi Ahmad , Bakhshayesh Masoumeh , Hayat Parisa
Published: July 2010

We previously showed that cAMP can inhibit DNA damage‐induced wild type p53 accumulation in human pre‐B NALM‐6 cells, leading to a profound reduction of their apoptotic response. Here, we provide evidence for the potentiation of DNA damage‐induced NF‐κB activation by cAMP. We found that inhibition of NF‐κB activation prevents the inhibitory effect of cAMP on doxorubicin‐induced apoptosis. Moreover, cAMP exerts its inhibitory effect on doxorubicin‐induced apoptosis in a PKA‐independent manner. The present study also shows that elevation of cAMP prolongs the phosphorylation of IκB and subsequent activation of NF‐κB in doxorubicin treated NALM‐6 cells in a proteasome‐dependent manner. Taken together, our results demonstrate that cAMP abrogates the balance between apoptotic and antiapoptotic transcription factors that are hallmarks of DNA damage signaling.
Verbraucherschutz und die Optimierung der Strukturen des Gesundheitssystems
Authors: Kranich Christoph
Published: July 2010

Einleitung

Wie steht Verbraucherschutz zum Gesundheitswesen und welche Rolle hat der Patient? Vom System der Fürsorge, das sich um kranke Menschen kümmert, wurde das Gesundheitswesen zum Supermarkt und der Kunde zum Objekt sich kreuzender Interessenströme mächtiger Akteure. Verbraucherschutz hat dieselben gegensätzlichen Ziele wie Prävention und Gesundheitsförderung: individuelle Hilfe, also die Arbeit mit Einzelnen, und systemische Unterstützung, bei der es um Hinweise auf strukturelle Mängel geht, die dringend abgestellt werden sollten.
Public Health (nicht) in den Medien
Authors: Stein Rosemarie
Published: July 2010

Einleitung

Public Health ist in Deutschland noch immer nicht populär und in den Medien so gut wie nicht präsent. Es werden einige Gründe dafür genannt, die zum Teil in der Sache selbst liegen, zum Teil medienspezifisch sind.
Carbon sequestration and its potential in agricultural soils of China
Authors: Sun Wenjuan , Huang Yao , Zhang Wen , Yu Yongqiang
Published: July 2010

Agricultural soils hold potential for the expansion of carbon sequestration. With this in mind, we investigated changes in the soil organic carbon (SOC) on the basis of an analysis of data sets extracted from 146 publications and further projected the SOC sequestration potential in China's cropland. Our results suggest that a significant increase in the SOC occurred in east and north China, while a decrease appeared in northeast China. As a whole, the organic carbon density in the topsoil to 30 cm depth increased by 3.36 (2.54 to 4.26) Mg/ha between 1980 and 2000. Accordingly, the croplands in China that cover an area of over 130 Mha sequestered 437 (331 to 555) Tg C, with an average rate of 21.9 (16.6 to 27.8) Tg/yr, during this period. The potential of SOC sequestration in China was estimated to be 2–2.5 Pg C, which could be achieved by the 2050s if crop production and field management are improved.
Sulphur deposition causes a large‐scale growth decline in boreal forests in Eurasia
Authors: Savva Yulia , Berninger Frank
Published: July 2010

Human activity has altered climate, atmospheric carbon dioxide concentrations, and the concentrations of several pollutants over the last few decades. At the same time, short‐term reactions of tree growth to climatic variations have changed during the last few decades, for reasons that are poorly understood. However, the effects of the pollutants on growth of boreal forests in these remote areas have not been quantified, but even small changes in the productivity of boreal forest should have a large effect on the carbon balance. Systematic growth changes of Scots pine, the most important forest species in boreal Eurasia, were analyzed over the last few decades using all 40 available tree ring chronologies north of 60°N latitude from the International Tree‐Ring Data Bank. We demonstrated a long‐term growth decline of Scots pine of about 17% or 0.0025 mm per year from the 1930s to the 1980s in northern Eurasia using a mixed‐effect model. This growth decline was estimated from radial growth when the age and climate effects were factored out. Although the study sites were previously considered low‐pollution pristine environments, the growth decrease was significantly related to sulphur depositions, while nitrogen depositions appeared to increase growth. Additionally, sulphur depositions caused Scots pine forests to be more sensitive to drought. Although the negative effects of local pollution on plant growth have been widely observed, the long‐term effects of sulphur emissions and its spread to ecosystems distant from the sources of pollution have never been previously documented at such a large scale.
Late Cretaceous arc development on the SW margin of the Caribbean Plate: Insights from the Golfito, Costa Rica, and Azuero, Panama, complexes
Authors: Buchs David M. , Arculus Richard J. , Baumgartner Peter O. , Baumgartner‐Mora Claudia , Ulianov Alexey
Published: July 2010

The processes of arc initiation at the margin of an oceanic plateau are remarkably well preserved along the southern coastline of eastern Costa Rica and western Panama. We present new results of a combined tectonostratigraphic and petrologic study with which protoarc initiation (75–73 Ma) at the margin of an oceanic plateau (89–85 Ma) is documented. Dykes of protoarc igneous rocks within the plateau and occurrences of protoarc igneous rocks are widely distributed. These types of field observations, geochemical data, and paleontologic ages for Late Cretaceous to Eocene fore‐arc rocks of the Golfito Complex and Azuero Marginal Complex (southern Costa Rica and western Panama) provide the first direct evidence that a Coniacian–early Santonian oceanic plateau forms the arc basement. Stratigraphic and geochemical constraints from Golfito and Azuero indicate subduction initiation in south Central America, associated with geochemically distinctive suprasubduction igneous rocks, occurred in the late Campanian along the margin of the newly defined Azuero Plateau. Overall, the Golfito Complex and Azuero Marginal Complex provide a significant opportunity for exploration of petrologic mechanisms linking some oceanic plateaus to the growth of continents. The Azuero Plateau may extend further toward the Colombian Basin and forms thickened Caribbean crust. It served as a nucleus for accretion of additional oceanic plateaus, seamounts, and oceanic islands of Pacific origins.
Rock magnetic property and paleointensity determination on historical Santorini lava flows
Authors: Spassov Simo , Valet Jean‐Pierre , Kondopoulou Despina , Zananiri Irene , Casas Lluís , Le Goff Maxime
Published: July 2010

Eight historical dacitic lava flows from Santorini with ages between 46 A.D. and 1950 A.D. (four of them within the past century) have been subjected to detailed rock magnetic analyses and various experiments of absolute paleointensity. Thermomagnetic measurements and acquisition of isothermal magnetization have revealed the presence of two physically distinct magnetic phases with Curie temperatures of 280°C and 500°C. In most of the samples, the second phase does not play a prominent role for the characteristic remanent magnetization, which is dominated by titanomagnetite. Magnetostatic interaction is very limited and does not considerably change upon heating. Back‐field curve spectra indicate a good thermochemical stability of these dacitic lava samples, which is also supported by the absence of noticeable changes in the remanent coercive force prior heating to 450°C. Hysteresis measurements show typical pseudo‐single‐domain behavior without noticeable superparamagnetism. Such characteristics were favorable to conduct and to test the most widely used experimental approaches for absolute paleointensity determination. Despite a success rate of 38%, the microwave technique has provided rather scattered within‐flow determinations. The results obtained from approaches involving alternating field demagnetization were biased by considerable differences between the NRM and the TRM coercive force spectra. We have also noticed that most determinations obtained by microwave heating differ from the historical field value at the site for the most recent flows. Last, techniques involving double‐heating protocols were successful due to a dominant low Curie temperature phase with a narrow grain size distribution. The results were characterized by low dispersion and were found in good agreement with the historical field.
Review of recent results on streamer discharges and discussion of their relevance for sprites and lightning
Authors: Ebert Ute , Nijdam Sander , Li Chao , Luque Alejandro , Briels Tanja , van Veldhuizen Eddie
Published: July 2010

It is by now well understood that large sprite discharges at the low air densities of the mesosphere are physically similar to small streamer discharges in air at standard temperature and pressure. This similarity is based on Townsend scaling with air density. First, the theoretical basis of Townsend scaling and a list of six possible corrections to scaling are discussed; then the experimental evidence for the similarity between streamers and sprites is reviewed. We then discuss how far present sprite and streamer theory has been developed, and we show how streamer experiments can be interpreted as sprite simulations. We review those results of recent streamer research that are relevant for sprites and other forms of atmospheric electricity and discuss their implications for sprite understanding. These include the large range of streamer diameters and velocities and the overall 3‐D morphology with branching, interaction and reconnection, the dependence on voltage and polarity, the electron energies in the streamer head, and the consecutive chemical efficiency and hard radiation. New theoretical and experimental results concern measurements of streamer spectra in air, the density dependence of streamer heating (hot leaders are unlikely at 80 km altitude and cold streamers are unlikely in liquids), and a discussion of the influence of magnetic fields on thermal electrons or on energetic electrons in streamers or sprites.
More evidence for a one‐to‐one correlation between Sprites and Early VLF perturbations
Authors: Haldoupis C. , Amvrosiadi N. , Cotts B. R. T. , van der Velde O. A. , Chanrion O. , Neubert T.
Published: July 2010

Past studies have shown a correlation between sprites and early VLF perturbations, but the reported correlation varies widely from ∼50% to 100%. The present study resolves these large discrepancies by analyzing several case studies of sprite and narrowband VLF observations, in which multiple transmitter‐receiver VLF pairs with great circle paths (GCPs) passing near a sprite‐producing thunderstorm were available. In this setup, the multiple paths act in a complementary way that makes the detection of early VLF perturbations much more probable compared to a single VLF path that can miss several of them, a fact that was overlooked in past studies. The evidence shows that visible sprite occurrences are accompanied by early VLF perturbations in a one‐to‐one correspondence. This implies that the sprite generation mechanism may cause also sub‐ionospheric conductivity disturbances that produce early VLF events. However, the one‐to‐one visible sprite to early VLF event correspondence, if viewed conversely, appears not to be always reciprocal. This is because the number of early events detected in some case studies was considerably larger than the number of visible sprites. Since the great majority of the early events not accompanied by visible sprites appeared to be caused by positive cloud to ground (+CG) lightning discharges, it is possible that sprites or sprite halos were concurrently present in these events as well but were missed by the sprite‐watch camera detection system. In order for this option to be resolved we need more studies using highly sensitive optical systems capable of detecting weaker sprites, sprite halos and elves.
Strain rates in northwestern Italy from spatially smoothed seismicity
Authors: Barani Simone , Scafidi Davide , Eva Claudio
Published: July 2010

This work presents seismic strain rate maps for the Western Alps and Northern Apennines (northern Italy) as derived from an earthquake catalog collecting both historical and instrumental data. Strain rates are calculated on the basis of the rate of seismic moment release using the Anderson method. Unlike previous applications, which determined the total strain rate associated with specific seismogenic sources, we have employed an innovative zoneless approach based on a spatially smoothed seismicity method. In addition, a Monte Carlo simulation procedure is applied to allow for uncertainty in the input data (e.g., magnitude to moment conversion, seismogenic thickness, maximum earthquake magnitude). Strain rate maps are developed by summing the moments of the earthquakes reported in the catalog and by using two different earthquake recurrence relations. Our results indicate that deformation rates are quite high, ranging from about 2 to 12 × 10−9 yr−1 in the Northern Apennines and from 0.5 to 6 × 10−9 yr−1 in the Western Alps. These values, however, are ∼1 order less than those derived from Global Positioning System measurements, suggesting that a portion of the recent deformation in northwestern Italy is related to aseismic processes. The discrepancies between seismic and geodetic strain rates may also indicate that the record of seismicity may not provide a sufficient time window for assessment of secular rates of moment release (or secular deformation rates) and rates of recurrence of large magnitude earthquakes in the study area.
Magnetic flux expulsion from the core as a possible cause of the unusually large acceleration of the north magnetic pole during the 1990s
Authors: Chulliat A. , Hulot G. , Newitt L. R.
Published: July 2010

The north magnetic pole (NMP) has been drifting in a north‐northwesterly direction since the 19th century. Both local surveys and geomagnetic models derived from observatory and satellite data show that the NMP suddenly accelerated during the 1990s. Its speed increased from about 15 km/yr in 1989 to about 60 km/yr in 2002, after which it started to decrease slightly. Using a Green's function, we show that this acceleration is mainly caused by a large, negative secular variation change in the radial magnetic field at the core surface, under the New Siberian Islands. This change occurs in a region of the core surface where there is a pair of secular variation patches of opposite polarities, which we suggest could be the signature of a so‐called “polar magnetic upwelling” of the type observed in some recent numerical dynamo simulations. Indeed, a local analysis of the radial secular variation and magnetic field gradient suggests that the secular variation change under the New Siberian Islands is likely to be accompanied by a significant amount of magnetic diffusion, in agreement with such a mechanism. We thus hypothesize that the negative secular variation change under the New Siberian Islands that produced the NMP acceleration could result from a slowdown of the polar magnetic upwelling during the 1990s. We finally note that the NMP drift speed is determined by such a combination of factors that it is at present not possible to forecast its future evolution.
Satellite monitoring of ammonia: A case study of the San Joaquin Valley
Authors: Clarisse Lieven , Shephard Mark W. , Dentener Frank , Hurtmans Daniel , Cady‐Pereira Karen , Karagulian Federico , Van Damme Martin , Clerbaux Cathy , Coheur Pierre‐François
Published: July 2010

Atmospheric ammonia (NH3) has recently been observed with infrared sounders from space. Here we present 1 year of detailed bidaily satellite retrievals with the Infrared Atmospheric Sounding Interferometer and some retrievals of the Tropospheric Emission Spectrometer over the San Joaquin Valley, California, a highly polluted agricultural production region. Several sensitivity issues are discussed related to the sounding of ammonia, in terms of degrees of freedom, averaging kernels, and altitude of maximum sensitivity and in relation to thermal contrast and concentration. We also discuss their seasonal dependence and sources of errors. We demonstrate boundary layer sensitivity of infrared sounders when there is a large thermal contrast between the surface and the bottom of the atmosphere. For the San Joaquin Valley, large thermal contrast is the case for daytime measurements in spring, summer, and autumn and for nighttime measurements in autumn and winter when a large negative thermal contrast is amplified by temperature inversion.
Horizontal cascade structure of atmospheric fields determined from aircraft data
Authors: Lovejoy S. , Tuck A. F. , Schertzer D.
Published: July 2010

Aircraft measurements of the power spectra of the horizontal wind field typically find a transition from ≈ k−5/3 to ≈ k−2.4 at scales somewhere around 40 km (k is a wave number). In the usual interpretation this represents a transition between an isotropic three‐dimensional (3‐D) (k−5/3) and an isotropic 2‐D (k−3) turbulence; we have recently argued that the turbulence is so highly anisotropic that it has different exponents in the horizontal and vertical. When coupled with gently sloping isobaric aircraft trajectories this predicts the break as a transition from a roughly horizontal spectrum at small scales to the spurious appearance of the vertical spectrum at large scales. If the atmosphere indeed has wide‐range horizontal scaling, then it is important to test out the multiplicative cascade models that predict its statistical behavior. In this paper, we do this by analyzing wind, temperature, pressure, and humidity data from the Winter Storm 2004 experiment using 24 aircraft legs, each 1120 km long and at 280 m resolution. We analyze both the turbulent fluxes and the fluctuations showing that in spite of the nonflat trajectories, there is good evidence of roughly planetary‐scale multiplicative cascades. By carefully determining the scale‐by‐scale effects of intermittency on the aircraft altitude and measurements, we estimate the corresponding scaling exponents. We argue that our results should finally permit the emergence of a long‐needed consensus about the basic scale‐by‐scale statistical properties of the atmosphere. They also point to the urgent need to develop anisotropic scaling models of turbulence.
A three‐dimensional characterization of Arctic aerosols from airborne Sun photometer observations: PAM‐ARCMIP, April 2009
Authors: Stone R. S. , Herber A. , Vitale V. , Mazzola M. , Lupi A. , Schnell R. C. , Dutton E. G. , Liu P. S. K. , Li S.‐M. , Dethloff K. , Lampert A. , Ritter C. , Stock M. , Neuber R. , Maturilli M.
Published: July 2010

The Arctic climate is modulated, in part, by atmospheric aerosols that affect the distribution of radiant energy passing through the atmosphere. Aerosols affect the surface‐atmosphere radiation balance directly through interactions with solar and terrestrial radiation and indirectly through interactions with cloud particles. Better quantification of the radiative forcing by different types of aerosol is needed to improve predictions of future climate. During April 2009, the airborne campaign Pan‐Arctic Measurements and Arctic Regional Climate Model Inter‐comparison Project (PAM‐ARCMIP) was conducted. The mission was organized by Alfred Wegener Institute for Polar and Marine Research of Germany and utilized their research aircraft, Polar‐5. The goal was to obtain a snapshot of surface and atmospheric conditions over the central Arctic prior to the onset of the melt season. Characterizing aerosols was one objective of the campaign. Standard Sun photometric procedures were adopted to quantify aerosol optical depth AOD, providing a three‐dimensional view of the aerosol, which was primarily haze from anthropogenic sources. Independent, in situ measurements of particle size distribution and light extinction, derived from airborne lidar, are used to corroborate inferences made using the AOD results. During April 2009, from the European to the Alaskan Arctic, from sub‐Arctic latitudes to near the pole, the atmosphere was variably hazy with total column AOD at 500 nm ranging from ∼0.12 to >0.35, values that are anomalously high compared with previous years. The haze, transported primarily from Eurasian industrial regions, was concentrated within and just above the surface‐based temperature inversion layer. Extinction, as measured using an onboard lidar system, was also greatest at low levels, where particles tended to be slightly larger than at upper levels. Black carbon (BC) (soot) was observed at all levels sampled, but at moderate to low concentrations compared with historical records. BC was highest near the North Pole, suggesting there had been an accumulation of soot within the Arctic vortex. Few, optically thick elevated aerosol layers were observed along the flight track, although independent lidar observations reveal evidence of the passage of volcanic plumes, which may have contributed to abnormally high values of AOD above 4 km. Enhanced opacity at higher altitudes during the campaign is attributed to an accumulation of industrial pollutants in the upper troposphere in combination with volcanic aerosol resulting from the March–April 2009 eruptions of Mount Redoubt in Alaska. The presence of Arctic haze during April 2009 is estimated to have reduced the net shortwave irradiance by ∼2–5 W m−2, resulting in a slight cooling of the surface.
The perfect debris flow? Aggregated results from 28 large‐scale experiments
Authors: Iverson Richard M. , Logan Matthew , LaHusen Richard G. , Berti Matteo
Published: July 2010

Aggregation of data collected in 28 controlled experiments reveals reproducible debris‐flow behavior that provides a clear target for model tests. In each experiment ∼10 m3 of unsorted, water‐saturated sediment composed mostly of sand and gravel discharged from behind a gate, descended a steep, 95‐m flume, and formed a deposit on a nearly horizontal runout surface. Experiment subsets were distinguished by differing basal boundary conditions (1 versus 16 mm roughness heights) and sediment mud contents (1 versus 7 percent dry weight). Sensor measurements of evolving flow thicknesses, basal normal stresses, and basal pore fluid pressures demonstrate that debris flows in all subsets developed dilated, coarse‐grained, high‐friction snouts, followed by bodies of nearly liquefied, finer‐grained debris. Mud enhanced flow mobility by maintaining high pore pressures in flow bodies, and bed roughness reduced flow speeds but not distances of flow runout. Roughness had these effects because it promoted debris agitation and grain‐size segregation, and thereby aided growth of lateral levees that channelized flow. Grain‐size segregation also contributed to development of ubiquitous roll waves, which had diverse amplitudes exhibiting fractal number‐size distributions. Despite the influence of these waves and other sources of dispersion, the aggregated data have well‐defined patterns that help constrain individual terms in a depth‐averaged debris‐flow model. The patterns imply that local flow resistance evolved together with global flow dynamics, contradicting the hypothesis that any consistent rheology applied. We infer that new evolution equations, not new rheologies, are needed to explain how characteristic debris‐flow behavior emerges from the interactions of debris constituents.
Mobilization of coarse surface layers in gravel‐bedded rivers by finer gravel bed load
Authors: Venditti J. G. , Dietrich W. E. , Nelson P. A. , Wydzga M. A. , Fadde J. , Sklar L.
Published: July 2010

Additions of sand to gravel beds greatly increase the mobility and flux of gravel. However, it is not known how additions of finer gravel to coarser gravel beds will affect the mobility of bed material. Here we examine the effect of fine gravel pulses on gravel bed material transport and near‐bed flow dynamics in a series of flume experiments. Bed material refers exclusively to sediment in the channel prior to the pulse introduction. The observations indicate that fine sediment pulses tend to migrate downstream in low‐amplitude waves. As the waves pass over the gravel bed, the interstitial pockets in the bed material surface fill and coarse gravel particles are entrained. This increases bed material transport rates and causes a distinct shift from a selective mobility transport regime where particles coarser than the bed material median (8 mm) make up <30% of the load to an equal mobility transport regime where bed materials coarser than 8 mm and finer than 8 mm are transported in equal proportions. The only possible source for this coarser bed load material is the sediment bed, suggesting that portions of the coarse surface layer are being mobilized. Observations of near‐bed velocity and turbulence suggest that fine gravel pulses cause fluid acceleration in the near‐bed region associated with a reduction in the level of turbulence produced at the sediment boundary. This accelerated fluid at the bed increases drag exerted on coarse surface layer particles, promoting their mobilization. Our findings suggest that, in general, finer bed sediment (not just sand) can mobilize coarser sediment and that expressions for the influence of sand on bed mobility need to be generalized on the basis of grain ratios.
Quantifying hyporheic exchange in a tidal river using temperature time series
Authors: Bianchin M. , Smith L. , Beckie R.
Published: July 2010

An investigation into groundwater‐surface water interaction (GSWI) beneath a large tidally influenced river was conducted to determine the effect of tides on the development of a hyporheic zone (HZ) and to quantify mixing of river water and groundwater. Temperature measurements, coupled with independent hydraulic head measurements, were used to detect groundwater flow within the riverbed. GWSI under tidal forcing produced a 1 m deep HZ. Time‐averaged riverbed temperature profiles displayed a distinct compressed convex pattern: clear evidence of net groundwater discharge. However, the instantaneous time series data indicate that riverbed temperatures were affected by tidal forcing to a depth of 1 m. Heat transport modeling revealed that instantaneous velocities within the shallow sediments of the riverbed are rather high, creating a zone of vigorous exchange during either a flooding or ebbing tide. Furthermore, the magnitude of the tidal pressure gradient was found to be significantly greater than the pressure gradient expected across 0.8 m high dunes, evidence that bed‐form‐driven exchange under these conditions, and this scale of observation, did not contribute to the development of the HZ. Conditions for exchange induced by shear and current bed form are favorable during ebbing tidal conditions only; flow paths are therefore limited in depth. Exchange flow paths in an estuary setting are complex; they are limited in duration and space and dominated by tidal pumping.
Improved forward and inverse analyses of saturated‐unsaturated flow toward a well in a compressible unconfined aquifer
Authors: Mishra Phoolendra Kumar , Neuman Shlomo P.
Published: July 2010

We present an analytical solution for flow to a partially penetrating well in a compressible unconfined aquifer that allows inferring its saturated and unsaturated hydraulic properties from drawdowns recorded in the saturated and/or unsaturated zone. We improve upon a previous such solution due to Tartakovsky and Neuman (2007) by (1) adopting a more flexible representation of unsaturated zone constitutive properties and (2) allowing the unsaturated zone to have finite thickness. Both solutions account for horizontal as well as vertical flows throughout the system. We investigate the effects of unsaturated zone constitutive parameters and thickness on drawdowns in the saturated and unsaturated zones as functions of position and time; demonstrate the development of significant horizontal hydraulic gradients in the unsaturated zone in response to pumping; validate our solution against numerical simulations of drawdown in a synthetic aquifer having unsaturated properties described by the van Genuchten‐Mualem constitutive model; use our solution to analyze drawdown data from a pumping test conducted by the U.S. Geological Survey at Cape Cod, Massachusetts; and compare our estimates of van Genuchten‐Mualem parameters with laboratory values obtained for similar materials in the area.
Does globalization of water reduce societal resilience to drought?
Authors: D'Odorico Paolo , Laio Francesco , Ridolfi Luca
Published: July 2010

Most food production depends, directly or indirectly, on freshwater resources. In the absence of importation of food commodities, population growth is constrained by the availability of local resources—including water—as well as by cultural and health‐related factors. The global trade of massive amounts of food makes societies less reliant on locally available water resources, thereby allowing some populations to exceed the limits posed by their local water budget. Thus, international trade implies a virtual transfer of water resources from areas of food production to importing regions. While it is recognized that in the short term this globalization of (virtual) water resources may prevent malnourishment, famine, and conflicts, its long‐term effects on the coupled human‐natural system remain poorly investigated. Here we develop a minimalist modeling framework to investigate the effect of the uncontrolled trade of food products on the resilience of human societies with respect to drought and famine. Our results suggest that in the long run the globalization of water resources reduces the societal resilience with respect to water limitations in that it leaves fewer options available to cope with exceptional droughts and crop failure.
Assessing slope stability in the Santa Barbara Basin, California, using seafloor geodesy and CHIRP seismic data
Authors: Blum J. A. , Chadwell C. D. , Driscoll N. , Zumberge M. A.
Published: July 2010

Seafloor slope instability in the Santa Barbara Basin, California, poses risk to the region. Two prominent landslides, the Goleta and Gaviota slides, occupy the northern flank, with a scarp‐like crack extending east from the headwall of the Gaviota slide towards the Goleta complex. Downslope creep across the crack might indicate an imminent risk of failure. Sub‐bottom CHIRP profiles with <1 m accuracy across the crack exhibit no evidence of internal deformation. Daily seafloor acoustic range measurements spanning the crack detected no significant motion above a 99% confidence level of ±7 mm/yr over two years of monitoring. These disparate data over different timescales suggest no active creep and that the crack is likely a relict feature that formed concomitantly with the Gaviota slide.
Reorganization of ice sheet flow patterns in Arctic Canada and the mid‐Pleistocene transition
Authors: Refsnider Kurt A. , Miller Gifford H.
Published: July 2010

Evidence for the evolution of Laurentide Ice Sheet (LIS) basal thermal regime patterns during successive glaciations is poorly preserved in the geologic record. Here we explore a new approach to constrain the distribution of cold‐based ice across central Baffin Island in the eastern Canadian Arctic over many glacial‐interglacial cycles by combining till geochemistry and cosmogenic radionuclide (CRN) data. Parts of the landscaped with geomorphic evidence for limited glacial erosion are covered by till characterized by high chemical index of alteration (CIA) values and CRN concentrations requiring complicated burial‐exposure histories. Till from regions scoured by glacial erosion have CIA values indistinguishable from local bedrock and CRN concentrations that can be explained by simple exposure following deglaciation. CRN modeling results based on these constraints suggest that the weathered tills were deposited by 1.9 to 1.2 Ma, and by that time the fiorded Baffin Island coastline must have developed close to its modern configuration as piracy of ice flow by the most efficient fiord systems resulted in a major shift in the basal thermal regime across the northeastern LIS. The resultant concentration of ice flow in fewer outlet systems may help explain the cause of the mid‐Pleistocene transition from 41‐ to 100‐kyr glacial cycles.
Narrowing of the upwelling branch of the Brewer‐Dobson circulation and Hadley cell in chemistry‐climate model simulations of the 21st century
Authors: Li Feng , Stolarski Richard. S. , Pawson Steven , Newman Paul A. , Waugh Darryn
Published: July 2010

Changes in the width of the upwelling branch of the Brewer‐Dobson circulation and Hadley cell in the 21st Century are investigated using simulations from a coupled chemistry‐climate model. In these model simulations the tropical upwelling region narrows in the troposphere and lower stratosphere. The narrowing of the Brewer‐Dobson circulation is caused by an equatorward shift of Rossby wave critical latitudes and Eliassen‐Palm flux convergence in the subtropical lower stratosphere. In the troposphere, the model projects an expansion of the Hadley cell's poleward boundary, but a narrowing of the Hadley cell's rising branch. Model results suggest that eddy forcing may also play a part in the narrowing of the rising branch of the Hadley cell.
Evaluation of bulk method for satellite‐derived latent heat flux
Authors: Iwasaki Shinsuke , Kubota Masahisa , Tomita Hiroyuki
Published: July 2010

To establish the most accurate bulk method for estimating the satellite‐derived latent heat flux (LHF), we evaluate four bulk methods by using direct eddy correlation and inertial dissipation fluxes obtained during 15 cruises in the tropics and midlatitudes. According to our results, the coupled ocean‐atmosphere response experiment (COARE) version 3 is the best algorithm for estimating the satellite‐derived LHF. Moreover, to clarify the error sources when measuring the satellite‐derived LHF including errors in meteorological values, we evaluated the LHF errors as an error function of the meteorological values. If we assume that the reported RMS error for the satellite‐derived meteorological values is valid, the RMS error of the LHF derived from instantaneous satellite data is estimated to be approximately 35–55 W/m2. The error determined by the bulk method contributes to 30–50% of the RMS error of the LHF.
Cortical and subcortical interactions during action reprogramming and their related white matter pathways
Authors: Neubert Franz-Xaver , Mars Rogier B. , Buch Ethan R. , Olivier Etienne , Rushworth Matthew F. S.
Published: July 2010

The right inferior frontal gyrus (rIFG) and the presupplementary motor area (pre-SMA) have been identified with cognitive control—the top-down influence on other brain areas when nonroutine behavior is required. It has been argued that they “inhibit” habitual motor responses when environmental changes mean a different response should be made. However, whether such “inhibition” can be equated with inhibitory physiological interactions has been unclear, as has the areas’ relationship with each other and the anatomical routes by which they influence movement execution. Paired-pulse transcranial magnetic stimulation (ppTMS) was applied over rIFG and primary motor cortex (M1) or over pre-SMA and M1 to measure their interactions, at a subsecond scale, during either inhibition and reprogramming of actions or during routine action selection. Distinct patterns of functional interaction between pre-SMA and M1 and between rIFG and M1 were found that were specific to action reprogramming trials; at a physiological level, direct influences of pre-SMA and rIFG on M1 were predominantly facilitatory and inhibitory, respectively. In a subsequent experiment, it was shown that the rIFG's inhibitory influence was dependent on pre-SMA. A third experiment showed that pre-SMA and rIFG influenced M1 at two time scales. By regressing white matter fractional anisotropy from diffusion-weighted magnetic resonance images against TMS-measured functional connectivity, it was shown that short-latency (6 ms) and longer latency (12 ms) influences were mediated by cortico-cortical and subcortical pathways, respectively, with the latter passing close to the subthalamic nucleus.
Fourier analysis and systems identification of the p53 feedback loop
Authors: Geva-Zatorsky Naama , Dekel Erez , Batchelor Eric , Lahav Galit , Alon Uri
Published: July 2010

A key circuit in the response of cells to damage is the p53–mdm2 feedback loop. This circuit shows sustained, noisy oscillations in individual human cells following DNA breaks. Here, we apply an engineering approach known as systems identification to quantify the in vivo interactions in the circuit on the basis of accurate measurements of its power spectrum. We obtained oscillation time courses of p53 and Mdm2 protein levels from several hundred cells and analyzed their Fourier spectra. We find characteristic spectra with distinct low-frequency components that are well-described by a third-order linear model with white noise. The model identifies the sign and strength of the known interactions, including a negative feedback loop between p53 and its upstream regulator. It also implies that noise can trigger and maintain the oscillations. The model also captures the power spectra of p53 dynamics without DNA damage. Parameters such as noise amplitudes and protein lifetimes are estimated. This approach employs natural biological noise as a diagnostic that stimulates the system at many frequencies at once. It seems to be a useful way to find the in vivo design of circuits and may be applied to other systems by monitoring their power spectrum in individual cells.