bluuebunny/crossref_metadata_2025 huggingface dataset:
On the structure of (co-Frobenius) Hopf algebras
Authors: Andruskiewitsch Nicolás , Cuadra Juan
Published: March 2013

We introduce a new filtration on Hopf algebras, the standard filtration, generalizing the coradical filtration. Its zeroth term, called the Hopf coradical, is the subalgebra generated by the coradical. We give a structure theorem: any Hopf algebra with injective antipode is a deformation of the bosonization of the Hopf coradical by its diagram, a connected graded Hopf algebra in the category of Yetter–Drinfeld modules over the latter. We discuss the steps needed to classify Hopf algebras in suitable classes accordingly. For the class of co-Frobenius Hopf algebras, we prove that a Hopf algebra is co-Frobenius if and only if its Hopf coradical is so and the diagram is finite dimensional. We also prove that the standard filtration of such Hopf algebras is finite. Finally, we show that extensions of co-Frobenius (resp. cosemisimple) Hopf algebras are co-Frobenius (resp. cosemisimple).
Equivariant Hopf Galois extensions and Hopf cyclic cohomology
Authors: Hassanzadeh Mohammad , Rangipour Bahram
Published: March 2013

We define the notion of equivariant

\times

-Hopf Galois extension and apply it as a functor between the categories of stable anti-Yetter–Drinfeld (SAYD) modules of the

\times

-Hopf algebras involved in the extension. This generalizes the result of Jara–Ştefan and Böhm–Ştefan on associating a SAYD modules to any ordinary Hopf Galois extension.
A generalised Green–Julg theorem for proper groupoids and Banach algebras
Authors: Paravicini Walther
Published: March 2013

The Green–Julg theorem states that

\mathrm{K}_0^G (B) \cong \mathrm{K}_0(\mathrm{L}^1(G,B))

for every compact group

G

and every

G

-

C^*

-algebra B. We formulate a generalisation of this result to proper groupoids and Banach algebras. This is a key result in the proof that the Bost assembly map is surjective for proper Banach algebra coefficients.
Preliminary data on a new opioid risk assessment measure: The Brief Risk Interview
Authors: Jones, PhD Ted , Moore, PhD Todd
Published: March 2013

Risk assessment and stratification have become a central issue in prescribing opioids to patients with chronic pain. Research to date on various risk screening measures has shown that a clinical interview by an experienced clinician offers superior predictive ability in identifying patients who are more likely to engage in future medication aberrant behavior. The current study represents a pilot study of an interview rating scale that is designed to replicate this clinical assessment. This study compares the predictions of medication aberrant behavior made by the Opioid Risk Tool, the Screener and Opioid Assessment for Patients with Pain- Revised, and the new interview rating scale, the Brief Risk Interview (BRI). A sample of 196 patients was assessed by each of the three risk measures and then follow-up data were gathered at 6 months post interview to determine which patients had engaged in medication aberrant behavior and had been discharged from the practice. The BRI shows superior predictive ability in identifying patients who later engage in medication aberrant behavior. Although more study in other settings is needed, these preliminary data suggest that the Brief Risk Interview could be a useful tool for any pain clinician in assessing risk through the use of information gathered in a brief interview. Keywords: medication aberrant behavior, opioid risk assessment, opioid pain management, Brief Risk Interview DOI:10.5055/jom.2013.0143
Comparison of efficacy between buprenorphine and tramadol in the detoxification of opioid (heroin)-dependent subjects
Authors: Chawla, MD Jatinder Mohan , Pal, MD Hemraj , Lal, MD Rakesh , Jain, PhD Raka , Schooler, PhD Nina , Balhara, MD Yatan Pal Singh
Published: March 2013

Aim/background: Tramadol is a synthetic opiate and a centrally acting weak µ-opioid receptor agonist. The potential advantages of tramadol include ease of administration, low abuse potential, and being nonscheduled. This study compared tramadol and buprenorphine for controlling withdrawal symptoms in patients with opioid dependence syndrome. Methods: Consenting male subjects between 20 and 45 years of age who fulfilled the ICD-10-DCR criteria for opiate dependence syndrome were randomly assigned in a double-blind, double-dummy placebo-controlled trial for detoxification. Those with multiple drug dependence, abnormal cardiac, renal and hepatic functions, psychosis, or organic mental illness were excluded. Assessments included Subjective Opiate Withdrawal Scale (SOWS), Objective Opiate Withdrawal Scale (OOWS), Visual Analog Scale (VAS), and Side Effect Check List. Subjects were evaluated daily and study duration was 10 days. Results: Sixty two subjects were enrolled. The mean SOWS and OOWS and VAS were significantly lower in the buprenorphine group on second and third day of detoxification as compared to the tramadol group. Although the retention rate was higher for buprenorphine group throughout the study, when compared with tramadol the difference was not significant on any day. Three subjects in the tramadol group had seizures. Conclusions: Tramadol was found to have limited detoxification efficacy in moderate to severe opioid withdrawal and substantial risk of seizures as compared to buprenorphine. Further studies are warranted to examine its efficacy in mild opioid withdrawal symptoms and its potential use in outpatient settings where its administration advantages may be valuable. Keywords: tramadol, buprenorphine, detoxification, opioids, heroin, randomized DOI:10.5055/jom.2013.0145
Composite measure to assess efficacy/gastrointestinal tolerability of tapentadol ER versus oxycodone CR for chronic pain: Pooled analysis of randomized studies
Authors: Merchant, PhD Sanjay , Provenzano, MD David , Mody, PharmD, MBA Samir , Ho, PhD Kai Fai , Etropolski, MD Mila
Published: March 2013

Objective: To evaluate a composite measure for chronic pain that balances pain relief with tolerability. Design: Post hoc meta-analysis of three randomized, multicenter, double-blind studies. Participants: Subjects with moderate-to-severe chronic osteoarthritis knee pain or low back pain who had been randomized to receive active treatment with tapentadol extended release (ER; n = 978) or oxycodone controlled release (CR; n = 999). Twenty-two subjects were excluded, mainly because they did not receive treatment. Main outcome measures: We defined the composite measure as GTE 30 percent pain relief without nausea/vomiting/constipation and without discontinuations (GTE 30 percent PRT [pain relief/tolerability]). We also considered GTE 50 percent PRT as well as GTE 30 percent and GTE 50 percent pain relief without any adverse events of any type. To further evaluate GTE 30 percent PRT, we studied its relationship with four patient-reported outcomes: EQ-5D, Physical and Mental Component Summaries of SF-36, Patient Global Impression of Change, and Patient Assessment of Constipation Symptoms. Results: At week 12, tapentadol ER recipients were more likely to have GTE 30 percent PRT than oxycodone CR recipients (OR, 3.15; 95% CI, 2.47, 4.00; p < 0.001). Significant differences were also observed with the other three composite measures (p < 0.001). At week 12, subjects with GTE 30 percent PRT had more favorable changes in all patient-reported outcomes than those without and were more likely to have threshold changes in EQ-5D and SF-36 (all p < 0.001). Conclusions: Tapentadol ER was associated with significantly better composite outcomes than oxycodone CR. Because both pain relief and gastrointestinal tolerability appeared to be related to outcomes, the composite measure may represent a useful tool for comparing opioids that merits further evaluation. Keywords: chronic pain, gastrointestinal tolerability, composite measure, opioid, oxycodone, tapentadol DOI:10.5055/jom.2013.0147
Cloud-resolving chemistry simulation of a Hector thunderstorm
Authors: Cummings K. A. , Huntemann T. L. , Pickering K. E. , Barth M. C. , Skamarock W. C. , Höller H. , Betz H.-D. , Volz-Thomas A. , Schlager H.
Published: March 2013

Abstract. Cloud chemistry simulations were performed for a Hector thunderstorm observed on 16 November 2005 during the SCOUT-O3/ACTIVE campaigns based in Darwin, Australia, with the primary objective of estimating the average NO production per lightning flash in this unique storm type which occurred in a tropical island environment. The 3-D WRF-Aqueous Chemistry (WRF-AqChem) model is used for these calculations and contains the WRF nonhydrostatic cloud-resolving model with online gas- and aqueous-phase chemistry and a lightning-NOx (LNOx) production algorithm. The model was initialized by inducing convection with an idealized morning sounding and sensible heat source, and initial condition chemical profiles from merged aircraft observations in undisturbed air. Many features of the idealized model storm, such as storm size and peak radar reflectivity, were similar to the observed storm. Tracer species, such as CO, used to evaluate convective transport in the simulated storm found vertical motion from the boundary layer to the anvil region was well represented in the model, with a small overestimate of enhanced CO at anvil altitudes. The lightning detection network (LINET) provided lightning flash data for the model and a lightning placement scheme injected the resulting NO into the simulated cloud. A lightning NO production scenario of 500 moles flash−1 for both CG and IC flashes yielded anvil NOx mixing ratios that compared well with aircraft observations and were also similar to those deduced for several convective modeling analyses in the midlatitudes and subtropics. However, these NO production values were larger than most estimates for tropical thunderstorms and given several uncertainties, LNOx production may have been as large as 600 moles flash−1. Approximately 85% of the simulated LNOx mass was located above 7 km in the later stages of the storm, which was greater than amounts found for subtropical and midlatitude convection. Modeled upper tropospheric NO2 partial columns were also considerably greater than most satellite observations of tropical marine convective events, as tropical island convection, such as Hector, is more vigorous and more productive of LNOx. Additional research is needed to investigate whether LNOx production per flash increases in storms with greater wind shear, such as this Hector storm, which showed significant variation in wind direction with altitude.
Observation-based assessment of stratospheric fractional release, lifetimes, and ozone depletion potentials of ten important source gases
Authors: Laube J. C. , Keil A. , Bönisch H. , Engel A. , Röckmann T. , Volk C. M. , Sturges W. T.
Published: March 2013

Abstract. Estimates of the recovery time of stratospheric ozone heavily rely on the exact knowledge of the processes that lead to the decomposition of the relevant halogenated source gases. Crucial parameters in this context are fractional release factors (FRFs) as well as stratospheric lifetimes and ozone depletion potentials (ODPs). We here present data from the analysis of air samples collected between 2009 and 2011 on board research aircraft flying in the mid- and high-latitude stratosphere and infer the above-mentioned parameters for ten major source gases: CFCl3 (CFC-11), CF2Cl2 (CFC-12), CF2ClCFCl2 (CFC-113), CCl4 (carbon tetrachloride), CH3CCl3 (methyl chloroform), CHF2Cl (HCFC-22), CH3CFCl2 (HCFC-141b), CH3CF2Cl (HCFC-142b), CF2ClBr (H-1211), and CF3Br (H-1301). The inferred correlations of their FRFs with mean ages of air reveal less decomposition as compared to previous studies for most compounds. When using the calculated set of FRFs to infer equivalent stratospheric chlorine, we find a reduction of more than 20% as compared to the values inferred in the most recent Scientific Assessment of Ozone Depletion by the World Meteorological Organisation (WMO, 2011). We also note that FRFs and their correlations with mean age are not generally time-independent as often assumed. The stratospheric lifetimes were calculated relative to that of CFC-11. Within our uncertainties the ratios between stratospheric lifetimes inferred here agree with the values in recent WMO reports except for CFC-11, CFC-12 and CH3CCl3. Finally, we calculate lower ODPs than recommended by WMO for six out of ten compounds, with changes most pronounced for the three HCFCs. Collectively these newly calculated values may have important implications for the severity and recovery time of stratospheric ozone loss.
Long-term monitoring of persistent organic pollutants (POPs) at the Norwegian Troll station in Dronning Maud Land, Antarctica
Authors: Kallenborn R. , Breivik K. , Eckhardt S. , Lunder C. R . , Manø S. , Schlabach M. , Stohl A.
Published: March 2013

Abstract. A first long-term monitoring of selected persistent organic pollutants (POPs) in Antarctic air has been conducted at the Norwegian Research station Troll (Dronning Maud Land). As target contaminants 32 PCB congeners, a- and g-hexachlorocyclohexane (HCH), trans- and cis-chlordane, trans- and cis-nonachlor, p,p'- and o,p-DDT, DDD, DDE as well as hexachlorobenzene (HCB) were selected. The monitoring program with weekly samples taken during the period 2007–2010 was coordinated with the parallel program at the Norwegian Arctic monitoring site (Zeppelin mountain, Ny-Ålesund, Svalbard) in terms of priority compounds, sampling schedule as well as analytical methods. The POP concentration levels found in Antarctica were considerably lower than Arctic atmospheric background concentrations. Similar as observed for Arctic samples, HCB is the predominant POP compound with levels of around 22 pg m−3 throughout the entire monitoring period. In general, the following concentration distribution was found for the Troll samples analyzed: HCB > Sum HCH > Sum PCB > Sum DDT > Sum chlordanes. Atmospheric long-range transport was identified as a major contamination source for POPs in Antarctic environments. Several long-range transport events with elevated levels of pesticides and/or compounds with industrial sources were identified based on retroplume calculations with a Lagrangian particle dispersion model (FLEXPART). The POP levels determined in Troll air were compared with 1 concentrations found in earlier measurement campaigns at other Antarctic research stations from the past 18 yr. Except for HCB for which similar concentration distributions were observed in all sampling campaigns, concentrations in the recent Troll samples were lower than in samples collected during the early 1990s. These concentration reductions are obviously a direct consequence of international regulations restricting the usage of POP-like chemicals on a worldwide scale.
Multi-model mean nitrogen and sulfur deposition from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): evaluation historical and projected changes
Authors: Lamarque J.-F. , Dentener F. , McConnell J. , Ro C.-U. , Shaw M. , Vet R. , Bergmann D. , Cameron-Smith P. , Doherty R. , Faluvegi G. , Ghan S. J. , Josse B. , Lee Y. H. , MacKenzie I. A. , Plummer D. , Shindell D. T. , Stevenson D. S. , Strode S. , Zeng G.
Published: March 2013

Abstract. We present multi-model global datasets of nitrogen and sulfate deposition covering time periods from 1850 to 2100, calculated within the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The computed deposition fluxes are compared to surface wet deposition and ice-core measurements. We use a new dataset of wet deposition for 2000–2002 based on critical assessment of the quality of existing regional network data. We show that for present-day (year 2000 ACCMIP time-slice), the ACCMIP results perform similarly to previously published multi-model assessments. For this time slice, we find a multi-model mean deposition of 50 Tg(N) yr−1 from nitrogen oxide emissions, 60 Tg(N) yr−1 from ammonia emissions, and 83 Tg(S) yr−1 from sulfur emissions. The analysis of changes between 1980 and 2000 indicates significant differences between model and measurements over the United States but less so over Europe. This difference points towards misrepresentation of 1980 NH3 emissions over North America. Based on ice-core records, the 1850 deposition fluxes agree well with Greenland ice cores but the change between 1850 and 2000 seems to be overestimated in the Northern Hemisphere for both nitrogen and sulfur species. Using the Representative Concentration Pathways to define the projected climate and atmospheric chemistry related emissions and concentrations, we find large regional nitrogen deposition increases in 2100 in Latin America, Africa and parts of Asia under some of the scenarios considered. Increases in South Asia are especially large, and are seen in all scenarios, with 2100 values more than double 2000 in some scenarios and reaching > 1300 mg(N) m−2 yr−1 averaged over regional to continental scale regions in RCP 2.6 and 8.5, ~30–50 % larger than the values in any region currently (2000). The new ACCMIP deposition dataset provides novel, consistent and evaluated global gridded deposition fields for use in a wide range of climate and ecological studies.
Intercomparison of polar ozone profiles by IASI/MetOp sounder with 2010 Concordiasi ozonesonde observations
Authors: Gazeaux J. , Clerbaux C. , George M. , Hadji-Lazaro J. , Kuttippurath J. , Coheur P.-F. , Hurtmans D. , Deshler T. , Kovilakam M. , Campbell P. , Guidard V. , Rabier F. , Thépaut J.-N.
Published: March 2013

Abstract. Validation of ozone profiles measured from a nadir looking satellite instrument over Antarctica is a challenging task due to differences in their vertical sensitivity with ozonesonde measurements. In this paper, ozone observations provided by the Infrared Atmospheric Sounding Interferometer (IASI) instrument onboard the polar-orbiting satellite MetOp are compared with ozone profiles collected between August and October 2010 at McMurdo Station, Antarctica, during the Concordiasi measurement campaign. The main objective of the campaign was the satellite data validation. With this aim 20 zero-pressure sounding balloons carrying ozonesondes were launched during this period when the MetOp satellite was passing above McMurdo. This makes the dataset relevant for comparison, especially because the balloons covered the entire altitude range of IASI profiles. The validation methodology and the collocation criteria vary according to the availability of global positioning system auxiliary data with each electro-chemical cell ozonesonde observation. The relative mean difference is shown to depend on the vertical range investigated. The analysis shows a good agreement in the troposphere (below 10 km) and middle stratosphere (25–40 km), where the differences are lower than 10%. However a significant positive bias of about 10–26% is estimated in the lower stratosphere at 10–25 km, depending on altitude. The positive bias in the 10–25 km range is consistent with previously reported studies comparing in situ data with thermal infrared satellite measurements. This study allows for a better characterization of IASI-retrieved ozone over the polar region during ozone depletion/recovery processes.
Analysis of the potential of one possible instrumental configuration of the next generation of IASI instruments to monitor lower tropospheric ozone
Authors: Sellitto P. , Dufour G. , Eremenko M. , Cuesta J. , Dauphin P. , Forêt G. , Gaubert B. , Beekmann M. , Peuch V.-H. , Flaud J.-M.
Published: March 2013

Abstract. To evaluate the added value brought by the next generation of IASI (Infrared Atmospheric Sounder Interferometer) instruments to monitor lower tropospheric (LT) ozone, we developed a pseudo-observation simulator, including a direct simulator of thermal infrared spectra and a full inversion scheme to retrieve ozone concentration profiles. We based our simulations on the instrumental configuration of IASI and of an IASI-like instrument, with a factor 2 improvement in terms of spectral resolution and radiometric noise. This scenario, that will be referred to as IASI/2, is one possible configuration of the IASI-NG (New Generation) instrument (the configuration called IASI-NG/IRS2) currently designed by CNES (Centre National d'Études Spatiales). IASI-NG is expected to be launched in the 2020 timeframe as part of the EPS-SG (EUMETSAT Polar System-Second Generation, formerly post-EPS) mission. We produced one month (August 2009) of tropospheric ozone pseudo-observations based on these two instrumental configurations. We compared the pseudo-observations and we found a clear improvement of LT ozone (up to 6 km altitude) pseudo-observations quality for IASI/2. The estimated total error is expected to be more than 35% smaller at 5 km, and 20% smaller for the LT ozone column. The total error on the LT ozone column is, on average, lower than 10% for IASI/2. IASI/2 is expected to have a significantly better vertical sensitivity (monthly average degrees of freedom surface–6 km of 0.70) and to be sensitive at lower altitudes (more than 0.5 km lower than IASI, reaching nearly 3 km). Vertical ozone layers of 4 to 5 km thickness are expected to be resolved by IASI/2, while IASI has a vertical resolution of 6–8 km. According to our analyses, IASI/2 is expected to have the possibility of effectively separate lower from upper tropospheric ozone information even for low sensitivity scenarios. In addition, IASI/2 is expected to be able to better monitor LT ozone patterns at local spatial scale and to monitor abrupt temporal evolutions occurring at timescales of a few days, thus bringing an expected added value with respect to IASI for the monitoring of air quality.
The effect of using limited scene-dependent averaging kernels approximations for the implementation of fast Observing System Simulation Experiments targeted on lower tropospheric ozone
Authors: Sellitto P. , Dufour G. , Eremenko M. , Cuesta J. , Peuch V.-H. , Eldering A. , Edwards D. P. , Flaud J.-M.
Published: March 2013

Abstract. Practical implementations of chemical OSSEs (Observing System Simulation Experiments) usually rely on approximations of the pseudo-observations by means of a prior parametrization of the averaging kernels, which describe the sensitivity of the observing systems to the target atmospheric species. This is intended to avoid the need for use of a computationally expensive pseudo-observations simulator that relies on full radiative transfer calculations. Here we present an investigation on how no, or limited, scene dependent averaging kernels parametrizations may misrepresent the sensitivity of an observing system, and thus possibly lead to inaccurate results of OSSEs. We carried out the full radiative transfer calculation for a three-days period over Europe, to produce reference pseudo-observations of lower tropospheric ozone, as they would be observed by a concept geostationary observing system called MAGEAQ (Monitoring the Atmosphere from Geostationary orbit for European Air Quality). The selected spatiotemporal interval is characterized by a peculiar ozone pollution event. We then compared our reference with approximated pseudo-observations, following existing simulation exercises made for both the MAGEAQ and GEOstationary Coastal and Air Pollution Events (GEO-CAPE) missions. We found that approximated averaging kernels may fail to replicate the variability of the full radiative transfer calculations. Then, we compared the full radiative transfer and the approximated pseudo-observations during a pollution event. We found that the approximations substantially overestimate the capability of the MAGEAQ to follow the spatiotemporal variations of the lower tropospheric ozone in selected areas. We conclude that such approximations may lead to false conclusions if used in an OSSE. Thus, we recommend to use comprehensive scene-dependent approximations of the averaging kernels, in cases where the full radiative transfer is computationally too costly for the OSSE being investigated.
Enhancement of photosynthetic carbon assimilation efficiency of phytoplankton assemblage in the future coastal ocean
Authors: Kim J.-H. , Kim K. Y. , Kang E. J. , Lee K. , Kim J.-M. , Park K. , Shin K. , Hyun B. , Jeong H. J.
Published: March 2013

Abstract. A mesocosm experiment was conducted to evaluate the effects of future climate conditions on photosynthesis and productivity of coastal phytoplankton. Natural phytoplankton assemblages were incubated in field mesocosms under the ambient condition (present condition: ca. 400 ppmv CO2 and ambient temp.), and two future climate conditions (acidification condition: ca. 900 ppmv CO2 and ambient temp.; greenhouse condition: ca. 900 ppmv CO2 and 3 °C warmer than ambient). Photosynthetic parameters of steady-state light responses curves (LCs; measured by PAM fluorometer) and photosynthesis–irradiance curves (P–I curves; estimated by in situ incorporation of 14C) were compared to three conditions during the experiment period. Under acidification, electron transport efficiency (αLC) and photosynthetic 14C assimilation efficiency (α) were 10% higher than those of the present condition, but maximum rates of relative electron transport (rETRm,LC) and photosynthetic 14C assimilation (PBmax) were lower than the present condition by about 19% and 7%, respectively. In addition, rETRm,LC and αLC were not significantly different between and greenhouse conditions, but PBmax and α of greenhouse conditions were higher than those of the present condition by about 9% and 30%, respectively. In particular, the greenhouse condition has drastically higher PBmax and α than the present condition more than 60% during the post-bloom period. According to these results, two future ocean conditions have major positive effects on the photosynthesis in terms of energy utilization efficiency for organic carbon fixation through the inorganic carbon assimilation. Despite phytoplankton taking an advantage on photosynthesis, primary production of phytoplankton was not stimulated by future conditions. In particular, biomass of phytoplankton was depressed under both acidification and greenhouse conditions after the the pre-bloom period, and more research is required to suggest that some factors such as grazing activity could be important for regulating phytoplankton bloom in the future ocean.
High-latitude environmental change during MIS 9 and 11: biogeochemical evidence from Lake El'gygytgyn, Far East Russia
Authors: D'Anjou R. M. , Wei J. H. , Castañeda I. S. , Brigham-Grette J. , Petsch S. T. , Finkelstein D. B.
Published: March 2013

Abstract. Marine isotope stages (MIS) 11 has been proposed as an analog for the present interglacial; however, terrestrial records of this time period are rare. Sediments from Lake El'gygytgyn (67°30' N, 172°5' E) in Far East Russia contain a 3.56 Ma record of climate variability from the Arctic. Here, we present the first terrestrial Arctic reconstruction of environmental and climatic changes from MIS 8 through 12 (289 to 464 ka) using organic geochemical proxies. Terrestrial vegetation changes, as revealed by plant leaf wax (n-alkane) indices and concentrations of arborinol (a biomarker for trees), show increased tree cover around the lake during interglacial periods, with higher concentrations observed during MIS 11 as compared to MIS 9. A similar pattern is also observed in records of aquatic productivity revealed by molecular indicators from dinoflagellates (dinosterol), eustigmatophyte algae (long-chain (C28–C32) 1, 15 n-alkyl diols) in addition to short-chain n-alkanes, where aquatic productivity is highest during MIS 11. Changes recorded in these molecular proxies show a similar structure to relative temperature variability as recorded by the MBT/CBT (Methylation of Branched Tetraether/Cyclization of Branched Tetraether) paleothermometer, based on branched glycerol dialkyl glycerol tetraethers (GDGTs). Additionally, relative MBT/CBT temperature changes generally track pollen and diatom δ18O temperature estimates, compiled by other studies, which suggest glacial-interglacial temperature changes of ~ 9 to 12 °C. These records of environmental and climatic change indicate Arctic sensitivity to external forcings such as orbital variability and atmospheric greenhouse gas concentrations. Overall, this study indicates that organic geochemical analyses of the Lake El'gygytgyn sediment archive can provide critical insight into the response of lake ecosystems and their sensitivity in high latitude regions.
Sea ice dynamics influence halogen deposition to Svalbard
Authors: Spolaor A. , Gabrieli J. , Martma T. , Kohler J. , Björkman M. , Isaksson E. , Varin C. , Vallelonga P. , Plane J. M. C. , Barbante C.
Published: March 2013

Abstract. Sea ice is an important parameter in the climate system and its changes impact upon the polar albedo and the atmospheric and oceanic circulation. Iodine (I) and bromine (Br) have been measured in a shallow ice core drilled at the summit of the Holtedahlfonna glacier (Northwest Spitsbergen, Svalbard). Changing I concentrations can be linked to the spring maximum sea ice extension. Bromine enrichment, indexed to the Br/Na sea water mass ratio, appears to be influenced by changes in the seasonal sea ice area. I is emitted from marine biota and so the retreat of spring sea ice coincides with enlargement of the open ocean surface which enhances marine primary production and consequent I emission. The observed Br enrichment can be explained by greater Br emissions during the Br explosion that have been observed to occur above first year sea ice during the early springtime. In this work we present the first comparison between halogens in surface snow and Arctic sea ice extension. Although further investigation is required to characterize potential depositional and post-depositional processes, these preliminary findings suggest that I and Br can be linked to variability in the spring maximum sea ice extension and seasonal sea ice surface area.
Cassirer's Phenomenology of Culture
Authors: Verene Donald Phillip
Published: March 2013

Ernst Cassirer claims in his Philosophy of Symbolic Forms that the transcendental analysis of science, ethical freedom, and aesthetic and organic natural forms of Kant's three Critiques is extended to other forms of culture, such as language, myth, and art. In this way, Cassirer holds, the “critique of reason becomes the critique of culture.” This claim tends to place Cassirer within the tradition of Neo-Kantianism. But this view is offset by Cassirer's further claim that his philosophy is based on a phenomenology of knowledge “as established and systematically grounded by Hegel.” He also subscribes to Hegel's dictum that “the True is the whole.” In order to achieve his philosophy of symbolic forms Cassirer joins Kantian transcendental method with Hegelian phenomenology. In so doing Cassirer replaces the idea of system with a conception of “systematic overview,” which he connects to a theory of “basis phenomena,” especially the basis phenomenon of the work (das Werk). This phenomenon allows him finally to conceive his philosophy of culture as a fulfillment of the Socratic pursuit of self-knowledge. In this way Cassirer's thought moves from an epistemology to a philosophical anthropology.
TheKairosof Philosophy
Authors: Shew Melissa
Published: March 2013

This essay seeks a philosophical understanding of the nature of kairos that, in turn, discloses the nature of philosophizing. This essay claims that the kairos of philosophy is dialogue, and that dialogue is kairological in two ways: (1) Dialogue is not just a phenomenon that occurs in chronological time but, rather, imposes its own time in order to see how life (or being) itself is disclosed to us; (2) dialogue is kairological because it denotes a moment in which we are pushed into the open, which demands our receptivity and response. Section I explains kairos as “circumstance” in Aristotle, as a required point of view in Heidegger, and as related to the beginning of creation in Schelling. Section II understands dialogue, as the kairos of philosophy, as a crisis—a breaking away from an ordinary understanding of and experience in the world. This destabilizing experience resonates with the untimeliness of philosophizing.
A Review of Fabrication Options and Power Electronics for Flapping-Wing Robotic Insects
Authors: Chen Chen , Tang Yichao , Wang Haoyu , Wang Yiding
Published: March 2013

Flapping-wing robotic insects are novel micro air vehicles (MAVs) inspired from biological insects in order to achieve a small size, high manoeuvrability and super remote ability. Such MAVs are centimetre scale flying robots with a number of applications, including exploration, environmental monitoring, rescue and reconnaissance. Due to the strict weight and power requirements of MAVs, the power electronics topologies need to be considered seriously. This paper describes state of the art power electronics topologies suitable for driving fl This -wing robotic insects. Comparisons are made in the resulting configurations of MAVs across several key metrics to estimate their performance. Discussion on the effect of performance gains in various power electronic topologies are abridged and presented.
A Preliminary Study of Fast Virtual Stent-Graft Deployment: Application to Stanford Type B Aortic Dissection
Authors: Chen Duanduan , Müller-Eschner Matthias , Rengier Fabian , Kotelis Drosos , Böckler Dittmar , Ventikos Yiannis , Xu Yong , Zeng Yanjun , Peng Yuhua , von Tengg-Kobligk Hendrik
Published: March 2013

Aortic dissection is the result of blood intruding into the layers of the aortic wall creating a duplicate channel along the aortic course. This considerably changes aortic morphology and thereby alters blood flow, inducing severe pathological conditions. Endovascular stent-graft placement has become an accepted treatment option for complicated Stanford type B aortic dissection. Stent-graft deployment aims to cover the primary entry, preventing most of the inflow to the false lumen, thereby promoting false lumen thrombosis and true lumen expansion. In recent years the application of this treatment has increased continuously. However, a fast and reasonable prediction for the released stent-graft and the resulting aortic remodelling prior to intervention is still lacking. In this paper, we propose a preliminary study on the fast virtual stent-graft deployment algorithm based on contact mechanics, spring analogy and deformable meshes. By virtually releasing a stent-graft in a patient-specific model of an aortic dissection type Stanford B, we simulate the interaction between the expanding stent-graft and the vessel wall (with low computational cost), and estimate the post-interventional configuration of the true lumen. This preliminary study can be finished within minutes and the results present good consistency with the post-interventional computed tomography angiography. It therefore confirms the feasibility and rationality of this algorithm, encouraging further research on this topic, which may provide more accurate results and could assist in medical decision-making.
Efficient Topological Localization Using Global and Local Feature Matching
Authors: Wang Junqiu , Yagi Yasushi
Published: March 2013

We present an efficient vision-based global topological localization approach in which different image features are used in a coarse-to-fine matching framework. Orientation Adjacency Coherence Histogram (OACH), a novel image feature, is proposed to improve the coarse localization. The coarse localization results are taken as inputs for the fine localization which is carried out by matching Harris-Laplace interest points characterized by the SIFT descriptor. The computation of OACHs and interest points is efficient due to the fact that these features are computed in an integrated process. The matching of local features is improved by using approximate nearest neighbor searching technique. We have implemented and tested the localization system in real environments. The experimental results demonstrate that our approach is efficient and reliable in both indoor and outdoor environments. This work has also been compared with previous works. The comparison results show that our approach has better performance with higher correct ratio and lower computational complexity.
Eikos logos-eikos mythos: un logos como representación del mundo
Authors: Cano Cuenca Jorge
Published: March 2013

In addition to operating as an epistemological vehicle, Timaios’ eikos logos is also a manifestation of an original conception of mimesis and of a deep consideration of the world as a teleological event and of the physis as an order. The problem with the physical logos is closely linked, on the one hand, with the truth of the sensible world itself and, on the other hand, with the mechanisms of sensation and the truth within them. What really matters is the way in which soul meets sensation and to generate thought of the physical and the degree of certainty it can reach, as well as and the conditions it is dependent upon.
Estrategias habitacionales de familias de sectores populares y medios residentes en el área metropolitana de Buenos Aires (Argentina)
Authors: Di Virgilio María Mercedes , Gil y de Anso María Laura
Published: March 2013

This article analyzes the various ways in which families face difficult habitat access conditions in the post-Fordist city. In order to do this, we have comparatively explored the housing strategies implemented by popular and middle class families residing in the Buenos Aires metropolitan area (Argentina). We have chosen popular and middle class families as a response to our interest in analyzing the effects that position in the class structure has on the actions carried out by families for their reproduction. From this point of view, the logic, the decisions, and the goals that lead to access to habitat and to the resources that are mobilized, vary according to the position that families occupy in the class structure. In this article, we advance in the analysis of housing strategies, emphasizing the differences and similarities that are observed among social groups that occupy differential positions in this structure but live in nearby locations in the city, and among social groups occupying similar positions in production and consumption but who reside in different areas and/or locations of the urban space.
Sobre subjetividad y (tele)trabajo. Una revisión crítica
Authors: Bustos Ordoñez Diana
Published: March 2013

In the context of important political, economic and social changes, telework becomes a phenomenon that combines many of the key factors for change: flexibility, information and communication technologies (ICT), and new ways of interaction. In order to analyze the relationship between subjectivity and telework, this article presents theoretical and empirical studies of several authors regarding subjects, subjectivity and (tele)work. The article examines different approaches, ranging from those which consider telework a degradation of traditional work with regard to social and personal functions, with perverse effects for people, to those which telework a challenge, or an opportunity, to create new dynamics, meanings, spaces, and, of course, ontological projects.
Women hold up half the sky – and half the burden of the HIV epidemic
Authors: Heidari Shirin , Kippax Susan , Sow Papa Salif , Wainberg Mark A
Published: March 2013

It has been said that women hold up half the sky. In the HIV epidemic, women carry half the burden of the epidemic, perhaps even more. The HIV burden on women is dramatically higher in some regions, certain age groups and among marginalized groups, such as female sex workers. Women's vulnerability to HIV is exacerbated by gender inequality and domestic violence.

The global effort towards elimination of paediatric HIV and keeping mothers alive deserves applause. However, the needs of women go beyond their child‐bearing age or potentials and/or reproductive desires and must be recognized in the global HIV agenda. In particular, more female‐controlled prevention tools are urgently required to allow women to protect themselves.

It is time to turn the tide through promoting gender equality and genuinely committing to gender‐responsive policies and programmes, and encouraging a more gender‐aware research agenda that can generate necessary evidence. In recognition of International Women's Day, the Journal of the International AIDS Society is pleased to launch a thematic series to highlight articles that address the different dimensions of HIV as they relate to women.
Approaches to estimate body condition from slaughter records in reindeer
Authors: Olofsson Anna , Danell Öje , Forslund Pär , Åhman Birgitta
Published: March 2013

Long-term fluctuations in population densities of reindeer and caribou are common, where pasture is the limiting resource. Pasture quality affects the nutritional status and production of the animals. Therefore, continuous information about changes in the grazing resources is important when making management decisions. The objective of this study was to investigate different possibilities of using routine and additional slaughter records as body condition indicators, and thereby indicators of pasture resources in the summer ranges of reindeer husbandry. Records from 696 reindeer slaughtered in the winter 2002/2003 were included in the study. We developed a model with carcass weight as body condition indicator and two different models combining fatness, conformation, carcass weight, and body size as body condition indicators. The results showed age and sex dependent differences between the variables, and differentiation of animal age and sex improved the precision of models. Adjusting weight for body size also improved weight as a body condition indicator in adults. Conformation and fatness had good resemblance to weight and body size adjusted weight and should preferably be included, together with carcass weight and body size measures, when estimating body condition from carcasses. Our analysis showed that using non-invasive slaughter records is a good and non-expensive method of estimating body condition in reindeer. Abstract in Swedish / Sammandrag:Tillvägagångssätt för skattning avkroppskondition hos ren från slaktregistreringarFluktuationer i ren- och caribou-populationers täthet över tiden är vanliga då betet är en begränsad resurs och beteskvalitén påverkar djurens kondition och produktion. Kontinuerligt uppdaterad information om förändringar i betesresurserna är viktigt i samband med beslutsfattande om förvaltning avresurserna. Syftet med denna studie var att utvärdera olika möjliga sätt att använda rutinregistreringar och extra registreringar vid slakt som konditionsindikatorer och därmed indikatorer för betestillstånd i sommarland inom rennäringen. Registreringar från 696 renar, slaktade under säsongen 2003/2003 användes i studien. Vi utvecklade en modell där slaktvikt var den enda indikatorn på kroppskondition, samt två modeller som kombinerade fett- och formklassificeringen med slaktvikt och kroppsstorlek som indikatorer på kroppskondition. Resultaten visade att renarnas ålder och kön ger skillnader i de olika variablerna och att modellernas noggrannhet ökar om djuren grupperas med tanke på ålder och kön. Att korrigera slaktvikten för kroppsstorlek ökade precisionen för vikt som konditionsindikator för vuxna djur. Fett- och formklassificeringen överensstämde väl med storlekskorrigerad slaktvikt och skulle med fördel kunna inkluderas tillsammans med slaktvikt och storlek för skattning avkroppskondition från slaktkroppar. Våra analyser visar att användning avslaktregistreringar är en bra och billig metod för att skatta kroppskonditionen hos renhjorden.
Establishment of Cladonia stellaris after artificial dispersal in an unfenced forest in northern Sweden
Authors: Roturier Samuel , Bergsten Urban
Published: March 2013

In 2002, fragments and whole thalli of reindeer lichen, mainly Cladonia stellaris, were spread in a typical Scots pine forest in northern boreal Sweden to study the survival and development after artificial lichen dispersal. The forest was not fenced, allowing reindeer access to graze. Lichens were dispersed in intact vegetation in 1 m2 plots by one of two methods: either as an intact lichen mat (patch) of 0.25 m2 in the centre of the plot or as fragments scattered (scatter) across the whole plot. The lichen was then monitored by photo inventory. In 2006, three years after the first inventory, all patch plots had been partially grazed by reindeer and the lichen cover measured in both patch and scatter plots had decreased severely. In 2008, the lichen cover in the patch and scatter plots had increased by up to 54% and 88%, respectively, of the cover measured during the first inventory in 2003. A significant increase in the number of fragments in the plots was also observed between 2006 and 2008, suggesting that in addition to growing like naturally established thalli, the lichen had spread and slowly colonized the plots. Dispersing lichen by the “patch” method appears to be less costefficient than the “scatter” method, if the area is grazed by reindeer. These results support the hypothesis that dispersal of reindeer lichen could be an effective means of restoring lichen stands, which are important for reindeer husbandry, even if the area is open to reindeer grazing.

Abstract in Swedish / Sammanfattning:

Etablering av Cladonia stellaris efter artificiell spridning i ej inhägnad skog i norra Sverige

Renlav (främst Cladonia stellaris) spreds manuellt 2002 i en talldominerad skog i norra Sverige för att studera lavens etablering efter artificiell spridning. Försöksområdet var inte hägnat utan öppet för renbete. Laven spreds i intakt markvegetation på 1 m2-ytor, antingen i form av intakta lavbålar (0,25 m2) i ytans centrum eller som fragment över hela provytan. Lavens etablering följdes med hjälp av fotoinventering. År 2006, tre år efter första inventeringen, hade alla provytor betats av ren och lavens täckningsgrad hade reducerats betydligt. Vid inventeringen 2008 hade lavens täckningsgrad ökat med upp till 54% (intakt lav) resp. 88% (lavfragment), i jämförelse med täckningsgraden den första inventeringen. Mellan 2006 och 2008 ökade antalet fragment per provyta signifikant vilket indikerar en fortsatt naturlig etablering med spridning via fragment. Att sprida lav i form av intakta lavbålar förefaller mindre kostnadseffektivt än spridning av lav i fragmentform om spridningsområdet är öppet för renbete. Resultaten utgör ett stöd för hypotesen att artificiell spridning av renlav kan vara ett effektivt sätt att restaurera viktiga renbetesområden, även om området inte är skyddat för renbete.