17,304 research outputs found
EEG–fMRI mapping of asymmetrical delta activity in a patient with refractory epilepsy is concordant with the epileptogenic region determined by intracranial EEG
We studied a patient with refractory focal epilepsy using continuous EEG-correlated fMRI. Seizures were characterized by head turning to the left and clonic jerking of the left arm, suggesting a right frontal epileptogenic region. Interictal EEG showed occasional runs of independent nonlateralized slow activity in the delta band with right frontocentral dominance and had no lateralizing value. Ictal scalp EEG had no lateralizing value. Ictal scalp EEG suggested right-sided central slow activity preceding some seizures. Structural 3-T MRI showed no abnormality. There was no clear epileptiform abnormality during simultaneous EEG–fMRI. We therefore modeled asymmetrical EEG delta activity at 1–3 Hz near frontocentral electrode positions. Significant blood oxygen level-dependent (BOLD) signal changes in the right superior frontal gyrus correlated with right frontal oscillations at 1–3 Hz but not at 4–7 Hz and with neither of the two frequency bands when derived from contralateral or posterior electrode positions, which served as controls. Motor fMRI activations with a finger-tapping paradigm were asymmetrical: they were more anterior for the left hand compared with the right and were near the aforementioned EEG-correlated signal changes. A right frontocentral perirolandic seizure onset was identified with a subdural grid recording, and electric stimulation of the adjacent contact produced motor responses in the left arm and after discharges. The fMRI localization of the left hand motor and the detected BOLD activation associated with modeled slow activity suggest a role for localization of the epileptogenic region with EEG–fMRI even in the absence of clear interictal discharges
Photosynthesis-irradiance responses in the Ross Sea, Antarctica: a meta-analysis
A meta-analysis of photosynthesis-irradiance measurements was completed using data from the Ross Sea, Antarctica, using a total of 417 independent measurements. P-m(B), the maximum, chlorophyll-specific, irradiancesaturated rate of photosynthesis, averaged 1.1 +/- 0.06 mu gC (mu g Chl)(-1) h(-1). Light-limited, chlorophyll-specific photosynthetic rates (alpha(B)) averaged 0.030 +/- 0.023 mu gC (mu g Chl)(-1) h(-1) (mu mol quanta m(-2) s(-1))(-1). Significant variations in P-m(B) and alpha(B) were found as a function of season, with spring maximum photosynthetic rates being 60% greater than those in summer. Similarly, alpha values were 48% greater in spring. There was no detectable effect of sampling location on the photosynthetic parameters, and temperature and macronutrient (NO3) concentrations also did not have an influence. However, irradiance and carbon dioxide concentrations, when altered under controlled conditions, exerted significant influences on photosynthetic parameters. Specifically, reduced irradiance resulted in significantly decreased P-m(B) and increased alpha(B) values, and increased CO2 concentrations resulted in significantly increased P-m(B) and alpha(B) values. Comparison of photosynthetic parameters derived at stations where iron concentrations were above and below 0.1nM indicated that reduced iron levels were associated with significantly increased P-m(B) values, confirming the importance of iron within the photosynthetic process. No significant difference was detected between stations dominated by diatoms and those dominated by the haptophyte Phaeocystis antarctica. The meta-analysis confirms the photosynthetic rates predicted from global analyses that are based solely on temperature and irradiance availability, but suggests that, for more accurate predictions of productivity in polar systems, a more detailed model that includes temporal effects of photosynthetic parameters will be required
Climate or rural development policy?
Being heavily energy dependent, it is not much of a surprise that Europe pays special attention to reducing the use of fossil fuels. Each one of the ten new member states is characterized by relatively low per capita energy consumption and relatively low energy efficiency, and the share of renewables in their energy mix tends to be low, too. The paper examines the problem when policy measures create a decrease in environmental capital instead of an increase. In this case it hardly seems justified to talk about environmental protection. The authors describe a case of a Hungarian rapeseed oil mill which would not be of too much interest on its own but given that almost all similar plants went bankrupt, there are some important lessons to learn from its survival. The enterprise the authors examined aimed at establishing a micro-regional network. They completed a brown-field development to establish a small plant on the premises of a former large agricultural cooperative. By partnering with the former employees and suppliers of the sometime cooperative, they enjoyed some benefits which all the other green-field businesses focusing on fuel production could not. The project improved food security, energy security and population retention as well
Effect of Inclusion Rate of Silage With or Without the Presence of Alpha-Amylase on Feedlot Performance, Carcass Characteristics, and Efficiency Measures
The experimental objective was to determine the interactions of silage variety and inclusion level in cattle finishing diets on cattle performance and agronomic returns to cropland when fed to beef cattle
Cost studies for commercial fuselage crown designs
Studies were conducted to evaluate the cost and weight potential of advanced composite design concepts in the crown region of a commercial transport. Two designs from each of three design families were developed using an integrated design-build team. A range of design concepts and manufacturing processes were included to allow isolation and comparison of cost centers. Detailed manufacturing/assembly plans were developed as the basis for cost estimates. Each of the six designs was found to have advantages over the 1995 aluminum benchmark in cost and weight trade studies. Large quadrant panels and cobonded frames were found to save significant assembly labor costs. Comparisons of high- and intermediate-performance fiber systems were made for skin and stringer applications. Advanced tow placement was found to be an efficient process for skin lay up. Further analysis revealed attractive processes for stringers and frames. Optimized designs were informally developed for each design family, combining the most attractive concepts and processes within that family. A single optimized design was selected as the most promising, and the potential for further optimization was estimated. Technical issues and barriers were identified
A mantle melting profile across the Basin and Range, SW USA
This is the published version. Copyright 2002 American Geophysical Union. All Rights Reserved.The major and trace element composition of late Cenozoic basalts (0–10 Ma) across the Basin and Range province (B&R) preserve a clear signal of mantle melting depth variations. FeO, Fe8.0, and Tb/Yb increase, whereas Si8.0 and Al8.0 decrease, from west to east across the B&R along a profile at 36°–37°N. These variations are qualitatively consistent with shallower melting beneath the Western Great Basin (WGB) than in the central B&R. In order to quantify the depth range and percent of decompression melting, we invert primary Na2O and FeO contents of basalts using a melting model based on the partitioning of FeO and MgO in olivine and Na2O in clinopyroxene. An independent inversion, using the rare earth elements (REE), corroborates the melting depths obtained from the major element model and places most of the melting beneath the central B&R in the garnet-peridotite stability field. We find that the shape of the melting region across the B&R closely mimics the shape of the mantle lithosphere, as inferred from geological and geophysical observations. Melting across the study area occurs largely within the asthenosphere and generally stops at the base of the mantle lithosphere. In the WGB, melting paths are shallow, from 75 to 50 km, and in some cases extend almost to the base of the crust. These melting paths are consistent with adiabatic melting in normal-temperature asthenosphere, beneath an extensively thinned (or absent) mantle lithosphere. Shallow melting is consistent with geobarometry and isotopic compositions of local mantle xenoliths. Lithospheric thinning was caused by thermal erosion during Mesozoic subduction and/or simple shear or foundering during Cenozoic extension. In contrast, melting beneath the central B&R occurs beneath thick mantle lithosphere and requires mantle potential temperatures 200°C hotter than normal (melting paths from 140 to 100 km). The excess temperature beneath the central B&R is consistent with active upwelling of hot mantle in this region
A revision of sexual mixing matrices in models of sexually transmitted infection
Two sexual mixing matrices previously used in models of sexually transmitted infections (STIs) are intended to calculate the probability of sexual interaction between age groups and sexual behaviour subgroups. When these matrices are used to specify multiple criteria for how people select sexual partners (such as age group and sexual behaviour class), their conditional probability structure means that they have in practice been prone to misuse. We constructed revised mixing matrices that incorporate a corrected conditional probability structure and then used one of them to examine the effect of this revision on population modelling of STIs. Using a dynamic model of human papillomavirus (HPV) transmission as an example, we examined changes to estimates of HPV prevalence and the relative reduction in age-standardised HPV incidence after the commencement of publicly funded HPV vaccination in Australia. When all other model specifications were left unchanged, the revised mixing matrix initially led to estimates of age-specific oncogenic HPV prevalence that were up to 11% higher than our previous models at certain ages. After re-calibrating the model by modifying unobservable parameters characterising HPV natural history, the revised mixing matrix yielded similar estimates to our previous models, predicting that vaccination would lead to relative HPV incidence reductions of 43% and 85% by 2010 and 2050, respectively, compared with 43% and 86% using the unrevised mixing matrix formulation. Our revised mixing matrix offers a rigorous alternative to commonly used mixing matrices, which can be used to reliably and explicitly accommodate conditional probabilities, with appropriate re-calibration of unobservable model parameter
The relationship between biophysical variables and halocarbon distributions in the waters of the Amundsen and Ross Seas, Antarctica
Little is known regarding the distribution of volatile halogenated organic compounds (halocarbons) in Antarctic waters and their relation to biophysical variables. During the austral summer (December to January) in 2007-08 halocarbon and pigment concentrations were measured in the Amundsen (100-130 degrees W) and Ross Sea (158 degrees W-160 degrees E). In addition, halocarbons were determined in air, snow and sea ice. The distribution of halocarbons was influenced to a large extent by sea ice, and to a much lesser extent by pelagic biota. Concentrations of naturally produced halocarbons were elevated in the surface mixed layer in ice covered areas compared to open waters in polynyas and in the bottom waters of the Ross Sea. Higher concentrations of halocarbons were also found in sea ice brine compared to the surface waters. Incubations of snow revealed an additional source of halocarbons. The distribution of halocarbons also varied considerably between the Amundsen and Ross Seas, mainly due to the different oceanographic settings. For iodinated compounds, weak correlations were found with the presence of pigments indicative of Phaeocystis, mainly in the Ross Sea. Surface waters of the Amundsen and Ross Seas are a sink for bromoform (saturation anomalies, SA, -83 to 11%), whereas sea ice was found to be both a source and sink (SA -61-97%). In contrast, both surface waters and sea ice were found to be a source of chloroiodomethane (SA -6-1 200% and 91-22 000 resp.). Consequently, polar waters can have a substantial impact on global halocarbon budgets and need to be included in large-scale assessments. (C) 2012 Elsevier B.V. All rights reserved
Coral Reef Conservation Program (CRCP) Local Action Strategy (LAS) Project 3B “Southeast Florida Coral Reef Fishery-Independent Baseline Assessment” – 2012-2013 Interim Report
Reef fishes are important biologic, ecologic, and economic resources of the marine ecosystem which must be managed for sustainability. Until recently there was no long-term monitoring program in place to assess the condition of fish resources of the northern Florida Reef Tract (FRT) (northern Miami-Dade, Broward, Palm Beach, and Martin counties). An assessment/monitoring plan for the northern Florida reef tract was designed through a joint cooperative effort by scientists at the University of Miami Rosenstiel School of Marine and Atmospheric Science, NOAA-Southeast Fisheries Science Center and Nova Southeastern University Oceanographic Center (NSUOC). This report is a synoptic compilation of the two-year data collection from all partner agencies, and includes data from the 234 and 354 sites or Primary Sampling Units (PSUs) sampled in 2012 and 2013, respectively. The majority of the field work was accomplished through funding granted to NSUOC. Significant amounts of data were also collected by multiple partner agencies that were able to dedicate their time and resources to the project. In 2012 funding for the first year of data collection was awarded by Florida Department of Environmental Protection (FDEP) to NSUOC on July 1st, 2012. Funding for a second year of sampling was awarded by National Oceanic and Atmospheric Administration (NOAA) Coral Reef Conservation Program (CRCP) to NSUOC through the National Coral Reef Institute Cooperative Agreement on June 18, 2013. Field sampling for each year began in May and ran through October. Funding for a third year of data collection (2014) and a final report was awarded by NOAA CRCP to NSUOC. Over the course of the two-year study period for this interim report, \u3e170,000 individual fish of 266 species were recorded. Total mean density for all sites and strata combined for both years was 162 fishes/SSU. For 2012, mean density was 151 fishes/SSU; in 2013 it was 168 fishes/SSU. However, in general, 2012 counts were higher at most sites. When low vs. high slope strata were compared, the high slope strata showed higher fish density. Likewise, species richness was higher at most sites in 2012 than 2013 and was also significantly higher for both years on sites with high slope. Multivariate analyses showed patterns in the reef fish communities associated with benthic habitats. Water depth was a primary determinant of fish distribution with differences in assemblages between shallow and deep sites. Also most of the surveys in the southern regions (Broward-Miami, Deerfield, and South Palm Beach) clustered tightly together indicating high similarity between communities in the deep habitats within these regions. Conversely, fish communities in North Palm Beach and Martin were much more variable and mostly separated in disparate areas of the plot. This suggests that the Martin and North Palm Beach fish communities are distinctly different from the southern regions. The dataset, in its entirety, provides the opportunity for further mining to examine individual species and reef fish assemblage correlations with a host of abiotic and biotic variables. Thus, from both management and ecological-sciences perspectives, it is a valuable resource. It is already clear there are significant differences in the geographic distribution of reef fishes at local and regional scales. There are interacting strata and latitudinal differences in total reef fish abundance, species distribution, sizes, and assemblage structure. The combination of data from all three years will provide a complete regional baseline fishery-independent assessment
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