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Efforts to improve epilepsy surgery outcomes have led to increased interest in the study of electroencephalographic oscillations outside the conventional EEG bands. These include fast activity above the gamma band, known as high frequency oscillations (HFOs), and infraslow activity (ISA) below the delta band, sometimes referred to as direct current (DC) or ictal baseline shifts (IBS). HFOs in particular have been extensively studied as potential biomarkers for epileptogenic tissue in light of evidence showing that resection of brain tissue containing HFOs is associated with good surgical outcomes. Not all HFOs are conclusively pathological, however, as they can be recorded in nonepileptic tissue and induced by cognitive, visual, or motor tasks. Consequently, efforts to distinguish between pathological and physiological HFOs have identified several traits specific to pathological HFOs, such as coupling with interictal spikes, association with delta waves, and stereotypical morphologies. On the opposite end of the EEG spectrum, sub-delta oscillations have been shown to co-localize with the seizure onset zones (SOZ) and appear in a narrower spatial distribution than activity in the conventional EEG frequency bands. In this report, we review studies that implicate HFOs and ISA in ictogenesis and discuss current limitations such as inter-observer variability and poor standardization of recording techniques. Furthermore, we propose that HFOs and ISA should be analyzed in addition to activity in the conventional EEG band during intracranial presurgical EEG monitoring to identify the best possible surgical margin.

To identify scalp EEG correlates of hippocampal spikes in patients with mesial temporal lobe epilepsy (mTLE).We recorded scalp and intracranial EEG simultaneously in 20 consecutive surgical candidates with mTLE. Hippocampal spikes were identified from depth electrodes during the first hour of sleep on the first night of recording in the epilepsy monitoring unit, and their scalp EEG correlates were identified.Hippocampal spiking rates varied widely from 101 to 2187 (556 ± 672, mean ± SD) spikes per hour among the subjects. Of the 16,398 hippocampal spikes observed in this study, 492 (3.0%) of hippocampal spikes with extensive involvement of lateral temporal cortex were associated with scalp interictal epileptiform discharges (IEDs) including spikes and sharp waves; 198 (1.2%) of hippocampal spikes with limited involvement of lateral temporal cortex were associated with sharp transients or sharp slow waves, and 78 (0.05%)of hippocampal spikes with no lateral temporal involvement were associated with small sharp spikes (SSS). SSS were not correlated with independent temporal neocortical spikes.There are morphologically heterogeneous scalp EEG correlates of hippocampal spikes including SSS, sharp transients, sharp slow waves, spikes, and sharp waves. SSS correlate with hippocampal spikes and are likely an EEG marker for mTLE. These findings have important clinical implications for the diagnosis and localization of mTLE, and provide new perspectives on criteria for defining scalp IEDs.

Author(s): Barnett, Jonathan; Baye, Michael R; Cooper, James C; Crane, Daniel A; Elzinga, Kenneth G; Epstein, Richard; Garza, Deborah; Hazlett, Thomas W; Hurwitz, Justin Gus; Klein, Benjamin; Klick, Jonathan; Lambert, Thomas A; Lipsky, Tad; Manne, Geoffrey A; Masten, Scott E; Ohlhausen, Maureen; Rill, James; Rybnicek, Jan; Smith, Vernon L; Teece, David; Willig, Robert; Wright, Joshua D; Yun, John M

Over the time span of more than a millennium, the ancient Maya polity of Tikal went through periods of growth, reorganization and adaptive cycles of various connected scales. Recent data show that following the reorganization of the Late Preclassic period, Tikal experienced an extended period of technological innovation and population growth that eventually stretched the carrying capacity of the available landscape. A hydraulic system was constructed that provided water for the community during the dry seasons: a powerful development in an area without a permanent water source. Agriculture was intensified using a combination of root crop agriculture, irrigated fields, arboriculture, household gardens, short fallow cropping systems and bajo margin cultivation. The net product of these diverse production activities helped to underwrite an enormous amassing of economic and political capital during the Late Classic period. Ultimately, in the mid-9th century CE, expansive growth combined with multiple system disturbances led to a collapse of the city’s social structure followed by abandonment of the site. The application of resilience theory as a conceptual framework is useful in helping to interpret the complex web of the underlying social and ecological domains that contributed to Tikal’s demise.

Objective Mesial temporal lobe epilepsy (mTLE) is the most common type of focal epilepsy, but often lacks scalp EEG correlates. We ask if hippocampal epileptiform discharges that are characteristic of mTLE are associated with small sharp spikes (SSS) recorded on scalp EEG. SSS are considered benign waveforms, so are not currently used as markers of epilepsy. Methods To determine if there is a relationship between SSS and hippocampal discharges, simultaneous scalp and hippocampal depth electrode EEGs were recorded from 27 patients being evaluated for possible mTLE. Scalp EEG waveforms were assessed at the time of hippocampal discharges identified on intracranial hippocampal depth electrodes. Results 15 of 27 patients had SSS on scalp EEG that were time locked to hippocampal epileptiform discharges measured intracranially. These hippocampal spikes tended to have overlying high frequency oscillations and to co-localize with a seizure onset zone, suggesting that they were pathological discharges. Conclusions There is a tight coupling between a subset of pathological hippocampal discharges and SSS. Significance SSS can be scalp EEG markers of mTLE rather than normal EEG variants.

Glutamic acid decarboxylase (GAD) antibody-associated encephalitis causes both acute seizures and chronic epilepsy with predominantly temporal lobe onset. This condition is challenging in diagnosis and management, and the incidence of GAD antibody (Ab)-related epilepsy could be much higher than commonly believed. Imaging and CSF evidence of inflammation along with typical clinical presentations, such as adult onset temporal lobe epilepsy (TLE) with unexplained etiology, should prompt testing for the diagnostic antibodies. High serum GAD Ab titer (≥2000U/mL or ≥20nmol/L) and evidence of intrathecal anti-GAD Ab synthesis support the diagnosis. Unlike other immune-mediated epilepsies, antiglutamic acid decarboxylase 65 (GAD65) antibody-mediated epilepsy is often poorly responsive to antiepileptic drugs (AEDs) and only moderately responsive to immune therapy with steroids, intravenous immunoglobulin (IVIG), or plasma exchange (PLEX). Long-term treatment with more aggressive immunosuppressants such as rituximab (RTX) and/or cyclophosphamide is often necessary and may be more effective than current immunosuppressive approaches. The aim of this review is to review the physiology, pathology, clinical presentation, related ancillary tests, and management of GAD Ab-associated autoimmune epilepsy by searching the keywords and to promote the recognition and the initiation of proper therapy for this condition.

The objective of this study was to determine the association of sleep with sudden unexpected death in epilepsy (SUDEP).We conducted a systematic review and meta-analysis based on literature search from databases PubMed, Web of Science, and Scopus using keywords "SUDEP", or "sudden unexpected death in epilepsy", or "sudden unexplained death in epilepsy". Sudden unexpected death in epilepsy was considered to occur during sleep if the patient was found in bed, if the SUDEP cases were documented as in sleep, or if the patient was found at bedside on the bedroom floor.Circadian pattern was documented in 880 of the 1025 SUDEP cases in 67 studies meeting the inclusion and exclusion criteria. Of the 880 SUDEP cases, 69.3% occurred during sleep and 30.7% occurred during wakefulness. Sudden unexpected death in epilepsy was significantly associated with sleep as compared to wakefulness (P0.001). In the subgroup of 272 cases in which circadian pattern and age were documented, patients 40years old or younger were more likely to die in sleep than those older than 40years (OR: 2.0; 95% CI=1.0, 3.8; P=0.05). In the subgroup of 114 cases in which both circadian pattern and body position at the time of death were documented, 87.6% (95% CI=81.1%, 94.2%) of patients who died during sleep were in the prone position, whereas 52.9% (95% CI=24.7%, 81.1%) of patients who died during wakefulness were in the prone position. Patients with nocturnal seizures were 6.3 times more likely to die in a prone position than those with diurnal seizures (OR: 6.3; 95% CI=2.0, 19.5; P=0.002).There is a strong association of SUDEP with sleep, suggesting that sleep is a significant risk factor for SUDEP. Although the risks of SUDEP associated with sleep are unknown and likely multifactorial, the prone position might be an important contributory factor.

We take a refreshing new look at boundedly rational quadratic models in economics using some elementary modeling of the principles put forward in the book Humanomics by Vernon L. Smith and Bart J. Wilson. A simple model is introduced built on the fundamental Humanomics principles of gratitude/resentment felt and the corresponding action responses of reward/punishment in the form of higher/lower payoff transfers. There are two timescales: one for strictly self-interested action, as in economic equilibrium, and another governed by feelings of gratitude/resentment. One of three timescale scenarios is investigated: one where gratitude/resentment changes much more slowly than economic equilibrium (“quenched model”). Another model, in which economic equilibrium occurs over a much slower time than gratitude/resentment evolution (“annealed” model) is set up, but not investigated. The quenched model with homogeneous interactions turns out to be a non-frustrated spin-glass model. A two-agent quenched model with heterogeneous aligning (ferromagnetic) interactions is analyzed and yields new insights into the critical quenched probability p ( 1 − p ) that represents the empirical frequency of opportunity for agent i to take action for the benefit (hurt) of other that invokes mutual gratitude (resentment). A critical quenched probability p i ∗ , i = 1 , 2 , exists for each agent. When p p i ∗ , agent i will choose action in their self-interest. When p > p i ∗ , agent i will take action sensitive to their interpersonal feelings of gratitude/resentment and thus reward/punish the initiating benefit/hurt. We find that the p i ∗ are greater than one-half, which implies agents are averse to resentful behavior and punishment. This was not built into the model, but is a result of its properties, and consistent with Axiom 4 in Humanomics about the asymmetry of gratitude and resentment. Furthermore, the agent who receives less payoff is more averse to resentful behavior; i.e., has a higher critical quenched probability. For this particular model, the Nash equilibrium has no predictive power of Humanomics properties since the rewards are the same for self-interested behavior, resentful behavior, and gratitude behavior. Accordingly, we see that the boundedly rational Gibbs equilibrium does indeed lead to richer properties.

Background The accurate localization of implanted ECoG electrodes over the brain is of critical importance to invasive diagnostic work-up for the surgical treatment of intractable epileptic seizures. The implantation of subdural electrodes is an invasive procedure which typically introduces non-uniform deformations of a subject’s brain, increasing the difficulty of determining the precise location of the electrodes vis-a-vis cortex. Formalization of this problem is used to define a novel solution for the optimal localization of subdural electrodes. New method We demonstrate that nonlinear transformation is required to accurately register the implanted electrodes to the non-deformed pre-surgical cortical surface, and that this problem is accommodated by utilizing known features of electrode geometry. Techniques to register chronically implanted subdural electrodes to the undistorted brain image are described and evaluated using simulated and clinical data. Results Principal Axis, our novel analysis method that estimates an electrode’s orientation by the moment of inertia of the solid electrode volume, proved to be the most reliable measure in both the simulated and clinical datasets. Comparison with existing methods This method of electrode translation along its principal axis is an improvement over other techniques, such as the limited view provided by intraoperative photography, and the image degradation inherent in post-operative MRI. Conclusions This technique compensates for alterations due to post-operative brain edema, and translates subdural electrodes to their original location on pre-operative MRI 3D models. This is helpful in the correct localization of seizure foci and functional mapping of epilepsy patients.

Previous studies in Chaco Canyon, New Mexico suggested that water management systems constructed during periods of increased aridity resulted in elevated salinity levels to the point that soils were no longer viable for growing cultigens. Salinity, pH, powder X-ray diffraction, and inductively coupled plasma atomic emission spectroscopy analyses of sediments and water collected from Chaco Canyon between the years 2013 and 2015 demonstrate conclusively that soils were suitable for the cultivation of maize by Ancestral Puebloans. Our findings clearly indicate that the salts are non-deleterious sulfate minerals. All of the cations and anions needed to form these minerals occur in the water of Chaco Canyon. Thus, increased soil salinity was not a critical factor in the abandonment of Chaco Canyon by Ancestral Puebloans. Sulfate and volcanogenic minerals increased soil fertility that allowed for the development and maintenance of an agricultural urban center in this dryland environment. Water management of sulfate and volcanic mineral rich soils created an environ ideal for maize agriculture. The occurrence of non-local Ancestral Puebloan maize in Chaco Canyon can be explained in terms of kinship mobility, the distance that goods and services move between extended families.

Powder X-ray diffraction, high-magnification microscopy, and whole rock X-ray fluorescence spectrometry analyses of sediment samples collected from an ancient Maya reservoir at Tikal, Guatemala in 2009 demonstrated conclusively that volcanic ash was repeatedly deposited on the site. To test the hypothesis that volcanic ash was a major contributor of new parent material to soils in the southern Yucatan Peninsula we used these same techniques to analyze samples taken from several natural depressions (bajos) in the region. Our findings clearly indicate that volcanic ash is a major constituent of regional soils. Hence, explosive volcanism was a critical factor in the development and maintenance of ancient Maya urban centers by renewing agricultural soils. These centers were typically low-density “garden cities” largely dependent on their immediate environs for agricultural production. For these cities to flourish in a difficult environment a flux of volcanic material occurring within an optimal window was critical. Regional wind patterns and rainfall are seasonal, linked to the annual shift in the Intertropical Convergence Zone (ITCZ). During the wet season, the ITCZ sits over the Yucatan Peninsula with Trade Winds and Easterly Waves predominating and blocking ash fall from reaching the Maya Lowlands from the volcanic arc to the south. During the dry season, the southward shift of the ITCZ allows westerly and southerly winds to bring erupted ash over the region. However, ash fall occurring during the dry season also posed a risk for ancient Maya, who were dependent on capturing and storing rainwater to meet their water needs because of the problem of reservoir fouling. Intermittent periods of increased aridity amplified drought frequency and severity, which likely contributed to periods of disruption in the course of Maya prehistory.

Hudson Canyon is the largest shelf-sourced canyon system off the east coast of the United States, and hosts a productive ecosystem that supports key fisheries. Here we report the results of a multi-year interdisciplinary study of the geological, geochemical, and physical oceanographic features and processes in the canyon that underpin that ecosystem. High-resolution multi-beam bathymetric and backscatter data show that the contrasting morphology of the two perpendicularly oriented branches at the head of the Hudson Canyon is indicative of different states of geomorphological activity and sediment transport. Tightly spaced ridges and gullies extend perpendicularly towards the canyon axis from the canyon walls. Numerous depressions are found at the base of the canyon walls or along the canyon axis at depths from 300 m to 600 m. Elevated concentrations of dissolved methane in the water column, where the highest density of depressions occur, suggests that methane is actively venting there. The topography and reflective floors of circular depressions in canyon walls and their association with methane maxima suggest that these represent active methane gas release-collapse pockmarks with carbonate floors. Patterns of irregular, low-relief, reflective depressions on the canyon floor may also represent methane release points, either as gas release or cold-seep features. The presence of methane maxima in a region of strong advective currents suggests continuous and substantial methane supply. Hydrographic observations in the canyon show that multiple layers of distinct inter-leaved shelf (cold, fresh) and slope (warm, salty) water masses occupy the head of the canyon during the summer. Their interactions with the canyon and with each other produce shifting fronts, internal waves, and strong currents that are influenced by canyon topography. Strong tidal currents with along-canyon-axis flow shear help to drive the advection, dispersion and mixing of dissolved materials in the water column that likely help support the rich canyon ecosystem.

An exceptionally robust result in experimental economics is the failure to observe equilibrium (subgame perfect) play in the ultimatum game. A heretofore unnoticed feature of the game is that neither player voluntarily chooses to play. Motivated by Adam Smith's proposition that beneficence—like that of non-equilibrium play in the ultimatum game—cannot be extorted by force, we offer the responder the opportunity to opt out of the game for a mere $1 payoff for both players. We observe far higher rates of equilibrium play, including highly unequal splits, than heretofore reported in binary choice versions of the game.

This paper develops a model of buyer (consumer) and seller (advertiser) strategic behavior in sponsored search auctions. Through its various extensions, the model is able to predict the effect of different ranking and payment policies on auction performance in terms of consumer surplus as well as advertisers’ and search engine profits. The theoretical model demonstrates that 1) payment policies should not have an effect on auction performance, 2) ranking policies that do not include the advertiser’s bid as a ranking criterion should not have an effect on auction performance 3) policies that use advertisers’ bids as the single ranking criterion should be just as good as using advertisers’ bids combined with other criteria over which advertisers have no short-term influence (e.g., relevance and click-through rate), 4) some sort of a coordination mechanism is necessary in order for buyers and sellers to achieve a fully efficient outcome, however, coordination should prove much more difficult when the bid is not used as at least one of the ranking criteria, 5) decreasing the number of sponsored links shown to consumers and displaying product prices should improve coordination and increase the likelihood of a fully efficient outcome. We use economically-motivated human subjects and the methods of experimental economics to test the first two of the model’s predictions. We investigate six different sponsored search auction formats: two different pricing policies (pay-per-transaction and pay-per-click) and three different ranking policies (rank by relevance, rank by click-through rate, & rank by both relevance and click-through rate). As predicted by the model we find no significant effect due to difference in ranking policies. However, contrary to the model’s predictions, we find significant differences in total surplus due to payment policies. We discuss two behavioral effects that could be the reason for these differences.

We develop and test a model that provides a unified account of the neural processes underlying behavior in a classical economic choice task. The model describes in a stylized way brain processes engaged in evaluating information provided by the experimental stimuli, and produces a consistent account of several important features of the decision process in different environments: e.g., when the probability is specified or not (ambiguous choices). These features include the choices made, the time to decide, the error rate in choice, and the patterns of neural activation. The model predicts that the further two stimuli are from each other in utility space, the shorter the reaction time will be, fewer errors in choice will be made, and less neural activation will be required to make the choice. The model also predicts that choices with ambiguity can be made more quickly and will require reduced neural activation in the horizontal intra-parietal sulcus than for choices with risk. Also, everything else being equal a larger value of certainty option in the choice will induce larger neural activation, and less experience on the part of the subject making choices will induce larger activation. We provide experimental evidence that is consistent with these predictions.

Purpose Urinary retention is a known complication of using an extravesical approach for ureteral reimplantation, especially in bilateral cases. The etiology may be secondary damage to pelvic nerves during ureteral dissection. Recent literature suggests that it is possible to visually identify these nerves during a robotic assisted laparoscopic approach. We performed an exploratory study to identify and document them in pediatric patients by means of electrophysiologic recordings. Material and methods Seven consecutive patients undergoing robotic assisted laparoscopic ureteral reimplantation with extravesical approach were prospectively enrolled in the study. Following dissection of the ureter below the level of vas deferens in male and the uterine artery in female, staying close to the adventitia and approaching the ureterovesical junction, the fibers as described in human cadaveric studies were identified dorsomedial to the ureter and preserved. Stimulating and recording electrodes were passed through to record post-synaptic compound muscle action potentials of the bladder. Results Even though the nerve fibers were visually identified, we were unable to consistently and reproducibly record compound muscle action potentials after stimulation of putative pelvic plexus fibers at the distal ureter, despite modulation in stimulation intensity, pulse characteristics, signal recording sensitivity and stimulator probe variation. Conclusions In this pilot study, the inconsistent findings raise questions about the exact location of the neurovascular bundle, nature of bladder smooth muscle electrophysiology and the appropriate methodology of evaluation. This may provide a reason to reexamine the intraoperatively expected location of pelvic plexus nerve fibers.

Enterohemorrhagic Escherichia coli cause approximately 1.5 million infections globally with 176,000 cases occurring in the United States annually from ingesting contaminated food, most frequently E. coli O157:H7 in ground beef or fresh produce. In severe cases, the painful prodromal hemorrhagic colitis is complicated by potentially lethal hemolytic uremic syndrome (HUS), particularly in children. Bacterial Shiga-like toxins (Stx1, Stx2) are primarily responsible for HUS and the kidney and neurologic damage that ensue. Small animal models are hampered by the inability to reproduce HUS with thrombotic microangiopathy, hemolytic anemia, and acute kidney injury. Earlier, we showed that nonhuman primates (Papio) recapitulated clinical HUS after Stx challenge and that novel therapeutic intervention rescued the animals. Here, we present detailed light and electron microscopic pathology examination of the kidneys from these Stx studies. Stx1 challenge resulted in more severe glomerular endothelial injury, whereas the glomerular injury after Stx2 also included prominent mesangiolysis and an eosinophilic inflammatory infiltration. Both toxins induced glomerular platelet-rich thrombi, interstitial hemorrhage, and tubular injury. Analysis of kidney and other organs for inflammation biomarkers showed a striking chemotactic profile, with extremely high mRNA levels for IL-8, monocyte chemoattractant protein 1, and macrophage inflammatory protein 1α and elevated urine chemokines at 48 hours after challenge. These observations give unique insight into the pathologic consequences of each toxin in a near human setting and present potential pathways for therapeutic intervention.

Three-dimensional (3D) fluorescence spectroscopy and parallel factor analysis (PARAFAC) were used to characterize oil components and to examine their fate and transformation processes during the unprecedented Deepwater Horizon oil spill in the Gulf of Mexico. Water samples were collected during two cruises in May and June 2010 soon after the spill began. Fluorescence excitation-emission matrix (EEM) spectra of seawater samples strongly resemble those of crude oil from the Macondo well and weathered oil collected from Gulf surface waters. This indicates the influence of oil on marine dissolved organic matter (DOM) which yielded elevated dissolved organic carbon (DOC) concentrations, higher UV–vis absorbance, and higher optically inferred molecular weight DOM in the water column. Two major types of DOM were found in the water column: one with low abundance but high optical activity and the other with high mass concentration yet low optical activity. Higher specific UV absorbance but lower spectral slope values observed for deep-water samples indicates the presence of less degraded or fresher crude oil in deep waters. Results of PARAFAC modeling revealed three oil-related components corresponding to crude and weathered oil in the water column: the most prominent one (namely C1) centered on Ex/Em 226/340 nm and the other two components (C2 and C6) centered on 236/360 and 252/311 nm, respectively. In addition, there is another DOM component (C3), partially representing chemically dispersed oil. Interestingly, the oil component ratios, an intensive property, varied with time and the degradation status of oil. We hypothesize that C2 (236/360 nm) is mostly a degraded product while C6 (252/311 nm) is a crude oil component with lower molecular weight, but at the same time, could be derived from oil degradation. Changes in fluorescence component ratios can thus be used as a compelling index to track the fate and transport of oil in marine environments.

The Integrated History and future of People on Earth (IHOPE) initiative is a global network of researchers and research projects with its International Program Office (IPO) now based at the Stockho ...

The vertical flux of particulate matter from the surface of the Ross Sea, Antarctica, has been suggested as being large, with substantial seasonal and spatial variations. We conducted a study in which vertical flux was quantified using sediment traps deployed at 200 m and compared to estimates calculated from one-dimensional budgets of nutrients (nitrogen and silicon). Estimates of flux were collected at two locations in the southern Ross Sea from late December to early February during four years: 2001–2002, 2003–2004, 2004–2005, and 2005–2006. Phytoplankton biomass and vertical flux varied substantially seasonally and spatially between the two sites, and among years. The greatest flux was observed in 2001–2002, with a short-term maximum organic carbon flux of 3.13 mmol m−2 d−1, and the summer mean organic carbon flux equal to 0.93 mmol m−2 d−1. In contrast, the mean carbon flux at the same site in 2003–2004 was over an order of magnitude less, averaging 0.19 mmol m−2 d−1, despite the fact that productivity in that year was substantially greater. In 2005–206 the contribution of fecal pellets to flux was smallest among all years, and the pellet contribution ranged from

Phytoplankton fluorescence, temperature and salinity were measured from December through February using in situ instruments deployed at two locations in the southern Ross Sea, Antarctica during the austral summers of three consecutive years (2003–2004, 2004–2005, and 2005–2006) to assess the short-term, seasonal and interannual variations in phytoplankton biomass and oceanographic conditions. The seasonal climatologies of physical forcing variables were also determined from satellite measurements, and the data from the two sites compared to the 2000–2009 mean. In situ fluorometers were deployed at three depths at 77S, 172.7E and 77.5S, 180. Significant differences between the two sites were consistently observed, confirming the anticipated high level of spatial and temporal heterogeneity. Chlorophyll fluorescence was maximal in late December, and generally decreased rapidly to modest levels in January and February. However, during 1 year (2003–2004) a secondary bloom was found, with summer maxima being similar to those observed during spring. Fluorescence displayed a strong diel cycle, with strong quenching during periods of maximum irradiance. The magnitude of this reduction was large (the minimum average fluorescence was 25% of the daily mean) and decreased with depth. Fluorescence varied interannually, with the absolute levels and temporal patterns being different among years. The two sites had different temperature/salinity properties as measured at 24 m, and both variables changed with time. During 2004–2005 we were able to continuously measure the photosynthetic quantum efficiency of PSII (F v /Fm) at 11 m, which revealed a minimum in December, and an increase in January, whereas the absolute fluorescence (Fo) decreased simultaneously. We suggest that this reflected a mixing event, whereby available irradiance increased, allowing a short period of growth in a more favorable optical environment. While substantial variations from the mean physical forcing were observed, the linkage of these physical variations with fluorescence was not always clear. Short-term (over 24-h) changes in fluorescence occurred, and were likely related to advective events. Wind events altered fluorescence in the surface layer, and these redistributed phytoplankton in the surface. The variability in chlorophyll fluorescence and physical forcing over a variety of scales in the Ross Sea provides insights into temporal–spatial coupling of phytoplankton.

Expert evaluation of electrocorticographic (ECoG) recordings forms the linchpin of seizure onset zone localization in the evaluation of epileptic patients for surgical resection. Numerous methods have been developed to analyze these complex recordings, including uni-variate (characterizing single channels), bi-variate (comparing channel pairs) and multivariate measures. Developing reliable algorithms may be helpful in clinical tasks such as localization of epileptogenic zones and seizure anticipation, as well as enabling better understanding of neuronal function and dynamics. Recently we have developed the frequency-entropy (F-E) similarity measure, and have tested its capability in mapping the epileptogenic zones. The F-E similarity measure compares time-frequency characterizations of two recordings. In this study, we examine the method's principles and utility and compare it to previously described bi-variate correspondence measures such as correlation, coherence, mean phase coherence and spectral comparison methods. Specially designed synthetic signals were used for illuminating theoretical differences between the measures. Intracranial recordings of four epileptic patients were then used for the measures' comparative analysis by creating a mean inter-electrode matrix for each of the correspondence measures and comparing the structure of these matrices during the inter-ictal and ictal periods. We found that the F-E similarity measure is able to discover spectral and temporal features in data which are hidden for the other measures and are important for foci localization.

This paper describes a curriculum for teaching economics using laboratory experiments. The key features of the curriculum are the low technology barriers, complete instructions for running the experiment and debriefing the results, and a guide for teacher-led roundtable discussions motivated by the Scottish philosophers. Our main goal is to present economic principles to young students in a way that is both exciting and accessible, while emphasizing the discovery process underlying wealth creation in modern economies using laboratory experiments.

International audience; This paper deals generally with testing questions that arise both when experimental observations are in accord with the actions we predict, and when they are not. In both cases the inference of truth from observation is inherently ambiguous, and we face the daunting challenge of using our experimental skills and imagination to reduce this ambiguity. Primarily and most difficult of all we have to constantly reevaluate everything, including ourselves, especially in examining how we talk about and interpret our data. Although I will be drawing on examples and experience from laboratory experiments, the issues I consider apply just as meaningfully to other empirical studies whether from field experiments or observations from past records of socioeconomic processes.

The temporal variability in currents, temperature, and particulate matter concentration were measured in the Mississippi Canyon axis where the thalweg was 300 m deep from May–July and August–November 1998 using current meters, thermographs, a light-scattering sensor, and sediment traps. Canyon sediments were sampled by coring and observed using an ROV video camera. Currents in the upper Mississippi Canyon generally oscillated up/down canyon with diurnal periodicity and were bottom-intensified. Mean current speed at 3.5 mab was approximately 8 cm s −1 during both deployments, reaching maximum speeds of over 50 cm s −1 under normal conditions. Based on current velocities, critical bed shear stress for resuspension of canyon-floor sediments was exceeded about 30% of the time during both deployments. In late September, Hurricane Georges passed 150 km NE of the study site, significantly intensifying current velocities, bed shear stress, resuspension, trap fluxes and temperature fluctuations. As the hurricane passed, maximum current speed reached 68 cm −s and temperature decreased ∼7 °C in less than two hours. Critical bed shear stress for sediment resuspension was exceeded approximately 50% of the time during the five days of hurricane influence. Further evidence for sediment resuspension was the five-fold (and perhaps 70–130 fold) increase in trap fluxes and compositional similarities between canyon surface sediment and material collected by traps.

We report on the design and testing of three auction mechanisms to maximize revenue and efficiency in the sale of two vintages of nitrous oxide emission allowances by the Commonwealth of Virginia in 2004. The three mechanisms considered were a combinatorial sealed bid (CSB) auction, a sequential English clock (SEC) auction, and a combinatorial English clock (CEC) auction. We find the SEC and CEC mechanisms to be superior the CSB when demand is relatively elastic. © 2008 Elsevier B.V. All rights reserved.

In earlier transmission electron microscopic studies, we have described pentilaminar gap junctional membrane invaginations and annular gap junction vesicles coated with short, electron-dense bristles. The similarity between these electron-dense bristles and the material surrounding clathrin-coated pits led us to suggest that the dense bristles associated with gap junction structures might be clathrin. To confirm that clathrin is indeed associated with annular gap junction vesicles and gap junction plaques, quantum dot immuno-electron microscopic techniques were used. We report here that clathrin associates with both connexin 43 (Cx43) gap junction plaques and pentilaminar gap junction vesicles. An important finding was the preferential localization of clathrin to the cytoplasmic surface of the annular or of the gap junction plaque membrane of one of the two contacting cells. This is consistent with the possibility that the direction of gap junction plaque internalization into one of two contacting cells is regulated by clathrin.

Anthropological archaeology provides the best window into how ancient societies coped with environmental exigencies and to what degree society itself may have been responsible for environmental change. By examining two pathways to social complexity—one based on technological breakthroughs (technotasking) and the other on highly organized labor management (labortasking)—early statecraft is assessed. Both the ancient Maya and the present-day Balinese are examined as case studies of the labortasking trajectory. The significance of past social organizational systems for assessing the immediate future is suggested.