bluuebunny/crossref_metadata_2025_split huggingface dataset:
Independent evolution of stratospheric temperatures in Jupiter's northern and southern auroral regions from 2014 to 2016
Authors: Sinclair J. A. , Orton G. S. , Greathouse T. K. , Fletcher L. N. , Tao C. , Gladstone G. R. , Adriani A. , Dunn W. , Moses J. I. , Hue V. , Irwin P. G. J. , Melin H. , Giles R. S. 
Published: May 2017

AbstractWe present retrievals of the vertical temperature profile of Jupiter's high latitudes from Infrared Telescope Facility‐Texas Echelon Cross Echelle Spectrograph measurements acquired on 10–11 December 2014 and 30 April to 1 May 2016. Over this time range, 1 mbar temperature in Jupiter's northern and southern auroral regions exhibited independent evolution. The northern auroral hot spot exhibited negligible net change in temperature at 1 mbar and its longitudinal position remained fixed at 180°W (System III), whereas the southern auroral hot spot exhibited a net increase in temperature of 11.1 ± 5.2 K at 0.98 mbar and its longitudinal orientation moved west by approximately 30°. This southern auroral stratospheric temperature increase might be related to (1) near‐contemporaneous brightening of the southern auroral ultraviolet/near‐infrared
emission measured by the Juno spacecraft and (2) an increase in the solar dynamical pressure in the preceding 3 days. We therefore suggest that 1 mbar temperature in the southern auroral region might be modified by higher‐energy charged particle precipitation.
Evidence for rapid topographic evolution and crater degradation on Mercury from simple crater morphometry
Authors: Fassett Caleb I. , Crowley Malinda C. , Leight Clarissa , Dyar M. Darby , Minton David A. , Hirabayashi Masatoshi , Thomson Bradley J. , Watters Wesley A. 
Published: May 2017

AbstractExamining the topography of impact craters and their evolution with time is useful for assessing how fast planetary surfaces evolve. Here, new measurements of depth/diameter (d/D) ratios for 204 craters of 2.5 to 5 km in diameter superposed on Mercury's smooth plains are reported. The median d/D is 0.13, much lower than expected for newly formed simple craters (~0.21). In comparison, lunar craters that postdate the maria are much less modified, and the median crater in the same size range has a d/D ratio that is nearly indistinguishable from the fresh value. This difference in crater degradation is remarkable given that Mercury's smooth plains and the lunar maria likely have ages that are comparable, if not identical. Applying a topographic diffusion model, these results imply that crater degradation is faster by a factor of approximately two on Mercury than on the Moon, suggesting more rapid landform evolution on Mercury at all scales.
Variability and trends in surface seawater pCO2 and CO2 flux in the Pacific Ocean
Authors: Sutton A. J. , Wanninkhof R. , Sabine C. L. , Feely R. A. , Cronin M. F. , Weller R. A. 
Published: May 2017

AbstractVariability and change in the ocean sink of anthropogenic carbon dioxide (CO2) have implications for future climate and ocean acidification. Measurements of surface seawater CO2 partial pressure (pCO2) and wind speed from moored platforms are used to calculate high‐resolution CO2 flux time series. Here we use the moored CO2 fluxes to examine variability and its drivers over a range of time scales at four locations in the Pacific Ocean. There are significant surface seawater pCO2, salinity, and wind speed trends in the North Pacific subtropical gyre, especially during winter and spring, which reduce CO2 uptake over the 10 year record of this study. Starting in late 2013, elevated seawater pCO2 values driven by warm anomalies cause this region to be a net annual CO2 source for the first time in the observational record, demonstrating how climate forcing can influence the timing of an ocean region shift from CO2 sink to source.
Gravity wave control on ESF day‐to‐day variability: An empirical approach
Authors: Aswathy R. P. , Manju G. 
Published: May 2017

AbstractThe gravity wave control on the daily variation in nighttime ionization irregularity occurrence is studied using ionosonde data for the period 2002–2007 at magnetic equatorial location Trivandrum. Recent studies during low solar activity period have revealed that the seed perturbations should have the threshold amplitude required to trigger equatorial spread F (ESF), at a particular altitude and that this threshold amplitude undergoes seasonal and solar cycle changes. In the present study, the altitude variation of the threshold seed perturbations is examined for autumnal equinox of different years. Thereafter, a unique empirical model, incorporating the electrodynamical effects and the gravity wave modulation, is developed. Using the model the threshold curve for autumnal equinox season of any year may be delineated if the solar flux index (F10.7) is known. The empirical model is validated using the data for high, moderate, and low solar epochs in 2001, 2004, and 1995, respectively. This model has the potential to be developed further, to forecast ESF incidence, if the base height of ionosphere is in the altitude region where electrodynamics controls the occurrence of ESF. ESF irregularities are harmful for communication and navigation systems, and therefore, research is ongoing globally to predict them. In this context, this study is crucial for evolving a methodology to predict communication as well as navigation outages.
Morphology of ionospheric F2 region variability associated with sudden stratospheric warmings
Authors: Gupta Sumedha , Upadhayaya A. K. 
Published: May 2017

AbstractThe effect of sudden stratospheric warming (SSW) on the F2 region ionosphere has been extensively analyzed for the major event of year 2009, apart from a few reports on other major and minor events. Morphology of ionospheric responses during SSW can be better comprehended by analyzing such warming events under different solar, geomagnetic, and meteorological conditions. We investigate the features of F2 region variability following the SSW events of 2010, 2011, 2012, 2013, 2014, 2015, and 2016, using ionosonde data from the Asian region covering a broad latitudinal range from 26.6°N to 45.1°N. We find perceptible ionospheric variations in electron densities during these warming events which is accompanied by a large variation of ~117% within enhancements, as compared to a meagre variation of ~11% within depressions, during these events. We also examine 6 months data at these latitudes and longitudes and find that the maximum and minimum variations in F2 layer critical frequency are observed during each SSW period. The influence of quasi‐stationary 16 day planetary waves is seen during these SSW events. Further, a recently proposed parameter “SSW integrated strength” by Vieira et al. (2017) to characterize SSW event with respect to ionosphere is also examined. It is seen that it does not fit well for these seven SSW events at these latitudes and longitudes.
Statistical characterization of the large‐scale structure of the subauroral polarization stream
Authors: Kunduri B. S. R. , Baker J. B. H. , Ruohoniemi J. M. , Thomas E. G. , Shepherd S. G. , Sterne K. T. 
Published: May 2017

AbstractThe subauroral polarization streams (SAPS) are latitudinally narrow regions of westward directed flows observed equatorward of the evening sector auroral oval. Previous studies have shown that SAPS generally occur during geomagnetically disturbed conditions and exhibit a strong dependence on geomagnetic activity. In this paper, we present the first comprehensive statistical study of SAPS using measurements from the U.S. midlatitude Super Dual Auroral Radar Network (SuperDARN) radars. The study period spans January 2011 to December 2014, and the results show that SuperDARN radars observe SAPS over a broad range of activity levels spanning storm time and nonstorm conditions. During relatively quiet conditions (−10 nT <Dst< 10 nT) SAPS occur 15% of the time and tend to be localized to the midnight sector and centered above 60° magnetic latitude. As the activity level increases, the peak SAPS location shifts equatorward and duskward. During moderately disturbed conditions (−75 nT <Dst <− 50 nT) SAPS occur 87% of the time and tend to be centered at 20 magnetic local time (MLT) and below 60° magnetic latitude. This behavior has been encoded into a new empirical model which uses Dst as input to estimate the probability of SAPS occurrence at a given magnetic latitude and MLT. Similar to some previous studies, the variation of SAPS speed with MLT is found to be nearly linear at low to moderate levels of geomagnetic activity but becomes increasingly nonlinear near dusk sector as geomagnetic activity increases. We interpret this behavior as indicative of active ionosphere‐thermosphere feedback playing an important role in modulating SAPS speeds.
Quantification of marine aerosol subgrid variability and its correlation with clouds based on high‐resolution regional modeling
Authors: Lin Guangxing , Qian Yun , Yan Huiping , Zhao Chun , Ghan Steven J. , Easter Richard , Zhang Kai 
Published: May 2017

AbstractOne limitation of most global climate models (GCMs) is that with the horizontal resolutions they typically employ, they cannot resolve the subgrid variability (SGV) of clouds and aerosols, adding extra uncertainties to the aerosol radiative forcing estimation. To inform the development of an aerosol subgrid variability parameterization, here we analyze the aerosol SGV over the southern Pacific Ocean simulated by the high‐resolution Weather Research and Forecasting model coupled to Chemistry. We find that within a typical GCM grid, the aerosol mass subgrid standard deviation is 15% of the grid‐box mean mass near the surface on a 1 month mean basis. The fraction can increase to 50% in the free troposphere. The relationships between the sea‐salt mass concentration, meteorological variables, and sea‐salt emission rate are investigated in both the clear and cloudy portion. Under clear‐sky conditions, marine aerosol subgrid standard deviation is highly correlated with the standard deviations of vertical velocity, cloud water mixing ratio, and sea‐salt emission rates near the surface. It is also strongly connected to the grid box mean aerosol in the free troposphere (between 2 km and 4 km). In the cloudy area, interstitial sea‐salt aerosol mass concentrations are smaller, but higher correlation is found between the subgrid standard deviations of aerosol mass and vertical velocity. Additionally, we find that decreasing the model grid resolution can reduce the marine aerosol SGV but strengthen the correlations between the aerosol SGV and the total water mixing ratio (sum of water vapor, cloud liquid, and cloud ice mixing ratios).
Benzylalkohol [MAK Value Documentation in German language, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: May 2017

AbstractThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated benzyl alcohol [100‐51‐6] to derive a maximum concentration at the workplace (MAK value), considering all toxicity endpoints. Available study reports and publications are described in detail.Benzyl alcohol is irritating to the eyes and the airways. In a 4‐week inhalation study in rats, microscopic lesions in the airways, especially in the lung, occurred at 1072 mg/m3. The NAEC is estimated to be 300 mg/m3, a concentration at which benzyl alcohol can occur as vapour, corresponding to 67 ml/m3. A MAK value of 5 ml/m3has been derived. As local effects are critical, benzyl alcohol is classified in Peak Limitation Category I with an excursion factor of 2.In developmental toxicity studies with benzyl alcohol in mice, foetotoxic effects occurred at 750 mg/kg body weight and day in the presence of marked maternal toxicity. The NOAEL was 550 mg/kg body weight and day; however, teratogenicity was not examined. Benzoic acid is the main metabolite of benzyl alcohol. Considering the developmental toxicity studies with sodium benzoate, the differences between the NOAEL for rats, mice, rabbits and hamsters scaled to an inhalation concentration at the workplace and the MAK value are considered so large that damage to the embryo or foetus is unlikely when the MAK value is observed. Therefore, benzyl alcohol is classified in Pregnancy Risk Group C.Benzyl alcohol is not regarded to be genotoxic or carcinogenic. Sensitization is not expected as benzyl alcohol was not a contact sensitizer in a local lymph node assay and there were no conclusive positive clinical findings of sensitizing effects on the skin. Skin contact is expected to contribute significantly to the systemic toxicity. Therefore, benzyl alcohol is designated with an “H”.
N‐Methylanilin [MAK Value Documentation in German language, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: May 2017

AbstractThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) of N‐methylaniline [100‐61‐8] considering all toxicity endpoints. Available publications and unpublished study reports are described in detail. Critical effect is the formation of methaemoglobin (MetHb). Adequate data in humans to derive a MAK value are not available; thus, data with rats are used. In rats, N‐methylaniline forms MetHb 2.7 times more efficiently than aniline. Based on the MAK value for aniline of 2 ml/m3, the MAK value for N‐methylaniline of 0.5 ml/m3is confirmed. As the critical effect is systemic, Peak Limitation Category II is retained; as the half‐life in blood is unknown, the default excursion factor of 2 is also retained. N‐Methylaniline remains in Pregnancy Risk Group D because developmental toxicity studies are lacking. The substance does not induce mutations in bacteria, but is clastogenic in mammalian cells. Studies on genotoxicity in vivo have not been performed. Adequate data to assess the carcinogenic potential of N‐methylaniline are not available. Data for the metabolite aniline are used to assess the carcinogenic potential of N‐methylaniline. Aniline induces spleen tumours in rats, but not in mice. The putative mode of action is an indirect tumour development by induction of MetHb and haemolytic effects which result in erythrocyte toxicity and its consequences, perturbations in iron metabolism in the spleen. The metabolites phenylhydroxylamine and nitrosobenzene are mainly responsible for the erythrocyte toxicity of aniline. As nitrosobenzene is also a metabolite of N‐methylaniline, a similar mode of action has to be assumed for N‐methylaniline. Therefore, a non‐genotoxic mode of action is of prime importance and genotoxic effects play at most a minor part provided the MAK and BAT values are observed. Thus, N‐methylaniline is classified as a suspected carcinogen in Carcinogen Category 3B. Skin contact may contribute significantly to systemic toxicity and the “H” notation is retained. There are no clinical data concerning the sensitizing activity of the substance. Results of a local lymph node assay in mice were negative.
2,4,6‐Tribromphenol [MAK Value Documentation in German language, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: May 2017

AbstractThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated 2,4,6‐tribromophenol [118‐79‐6] to derive a maximum concentration at the workplace (MAK value), considering all toxicity endpoints. Available study reports and publications are described in detail.2,4,6‐Tribromophenol is irritating to the rabbit eye. Therefore, irritation of the respiratory tract has to be assumed; however, the only available repeated dose inhalation study in rats is of limited validity. The lowest NOAEL for systemic toxicity in an oral study in rats was 100 mg/kg body weight and day. Beginning from 300 mg/kg body weight and day, increased creatinine levels in the blood of male rats and intense salivation in male and female animals were observed. Due to the irritant potential and the lack of a valid inhalation study, no MAK value could be set and 2,4,6‐tribromophenol is classified in Section II b of the List of MAK and BAT Values.In a reproduction and developmental toxicity screening test the NOAEL for fertility and foetotoxicity was 300 mg/kg KG body weight and day. Teratogenicity was not investigated.2,4,6‐Tribromophenol is not regarded to be genotoxic or carcinogenic. Sensitization is not expected due to limited animal studies and human experience. Skin contact is not expected to contribute significantly to the systemic toxicity.
Tetrachlorethen [MAK Value Documentation in German language, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: May 2017

Abstract
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated tetrachloroethylene [127‐18‐4] to derive a maximum concentration at the workplace (MAK value), considering all toxicity endpoints. Available study reports and publications are described in detail.
Results from human studies do not point to a genotoxic potential of tetrachloroethylene. In vitro and in vivo studies in mammalian cells do not show a distinct genotoxic potential. From epidemiologic and animal studies there is concern that tetrachloroethylene could be carcinogenic for humans; therefore, tetrachloroethylene has been classified in Carcinogen Category 3B. However, since carcinogenic effects are judged to be not predominantly caused by genotoxic mechanisms, a MAK value can be derived.

Neurotoxicity is considered the most sensitive endpoint for tetrachloroethylene. In volunteers, repeated daily 4‐hour inhalation exposure caused small but significant effects on visual evoked potentials. The NOAEC was 10 ml/m
3
, but as only weak effects were observed at the LOAEC of 50 ml/m
3
, 20 ml/m
3
is regarded as the NAEC. As a doubling of uptake is expected under workplace conditions, a MAK value of 10 ml/m
3
has been set. As the critical effect is systemic, tetrachloroethylene is assigned to Peak Limitation Category II. The default excursion factor of 2 is set as the half‐life in the central nervous system is unknown.

There is limited evidence suggesting that women working in a dry‐cleaner have an increased risk of spontaneous abortion. But the limited validity of the studies is not sufficient to prove a causal relationship. In developmental toxicity studies, NOAECs for developmental toxicity of 65 and 217 ml/m
3
in rats, 500 ml/m
3
in rabbits, and a LOAEC of 217 ml/m
3
in mice were obtained. The NOAEC for behavioural toxicity in the offspring of treated rats was 100 ml/m
3
. The differences between these NOAECs as well as the LOAEC and the MAK value are considered so large that damage to the embryo or foetus is unlikely when the MAK value is observed. Therefore, tetrachloroethylene is classified in Pregnancy Risk Group C.

Sensitization is not expected due to results of animal studies and experience in humans. Skin contact is expected to contribute significantly to the systemic toxicity of tetrachloroethylene. Therefore, designation with an “H” is confirmed.
4‐
tert
‐Octylphenol [MAK Value Documentation in German language, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: May 2017

Abstract

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated the developmental toxicity of 4‐tert‐octylphenol [140‐66‐9]. In 2015, the maximum concentration at the workplace (MAK value) for 4‐tert‐octylphenol was set at 0.5 ml/m
3
(4.3 mg/m
3
).

In a screening study in rats with gavage administration, litter size and body weight of the progeny at postnatal day 4 was reduced at 500 mg/kg body weight and day, accompanied by maternal toxicity. A NOAEL for foetotoxicity of 250 mg/kg body weight and day was derived, corresponding to a concentration of 28.5 ml/m
3
at the workplace. In a 2‐generation feeding study in rats, foetotoxicity was not observed until postnatal day 13. At 111–369 mg/kg body weight and day, vaginal opening or preputial separation of the F2 progeny was delayed. A NOAEL of 10.9–32.6 mg/kg body weight and day was derived for postnatal developmental toxicity in rats, corresponding to 1.2–3.7 ml/m
3
. Because adequate studies of prenatal developmental toxicity over the complete period of organogenesis are lacking, data are not sufficient for classification and 4‐tert‐octylphenol is assigned to Pregnancy Risk Group D.
Methylstyrol (Vinyltoluol) (alle Isomere) [MAK Value Documentation in German language, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: May 2017

AbstractThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated methyl styrene [25013‐15‐4] considering all toxicological endpoints and revised the maximum concentration at the workplace (MAK value). Publications are described in detail.In long‐term inhalation studies with methyl styrene, inflammation and hyperplasia were observed in nasal tissue of rats and mice with LOAECs of 100 ml/m3 and 10 ml/m3, respectively. As was shown with styrene, the reason for mice being more susceptible than rats is differences in the rates of phase I and phase II metabolism. While the rate of oxidation to the epoxide is almost the same in rats and mice, the detoxification via epoxide hydrolase and GSH‐transferase is about 10‐fold faster in rats than in mice. In human nasal tissue in vitro, oxidation of styrene is minimal but metabolization via epoxide hydrolase and GSH‐transferase occurs at almost the same rate as in rat nasal tissue. Therefore, humans are much less sensitive to nasal effects of styrene and this species difference is assumed to be the same for the similarly metabolized methyl styrene. The MAK value is derived from the LOAEC in rats and set at 20 ml methyl styrene/m3. Due to the local effect being critical, the substance is assigned to Peak Limitation Category I. As there was no sensory irritation in volunteers with methyl styrene at 50 ml/m3, the excursion factor is 2.Methyl styrene has a limited genotoxic potential only at systemically toxic doses, and 2‐year carcinogenicity studies were negative.Dermal absorption does not contribute significantly to the systemic toxicity and investigations in humans and animals do not indicate a significant sensitizing effect.Because 3 studies on the developmental toxicity of methyl styrene are only available as summaries and the reason for the differing effects cannot be evaluated, methyl styrene is assigned to Pregnancy Risk Group D.