Mineral aerosol impacts on climate through radiative forcing by natural dust sources are examined in the current, last glacial maximum, pre‐industrial and doubled‐carbon dioxide climate. Modeled ...globally averaged dust loadings change by +88%, +31% and −60% in the last glacial maximum, pre‐industrial and future climates, respectively, relative to the current climate. Model results show globally averaged dust radiative forcing at the top of atmosphere is −1.0, −0.4 and +0.14 W/m2 for the last glacial maximum, pre‐industrial and doubled‐carbon dioxide climates, respectively, relative to the current climate. Globally averaged surface temperature changed by −0.85, −0.22, and +0.06 °C relative to the current climate in the last glacial maximum, pre‐industrial and doubled carbon dioxide climates, respectively, due solely to the dust radiative forcing changes simulated here. These simulations only include natural dust source response to climate change, and neglect possible impacts by human land and water use.
This study assessed the sensitivity of the West African climate to varying vegetation fractions. The assessment of a such relationship is critical in understanding the interactions between land ...surface and atmosphere. Two sets of convection‐permitting simulations from the UK Met Office Unified Model at 12 km horizontal resolution covering the monsoon period May–September (MJJAS) were used, one with fixed vegetation fraction (MF‐V) and the other with time‐varying vegetation fraction (MV‐V). Vegetation fractions are based on MODIS retrievals between May and September. We focused on three climatic zones over West Africa: Guinea Coast, Sudanian Sahel, and the Sahel while investigating heat fluxes, temperature, and evapotranspiration. Results reveal that latent heat fluxes are the most strongly affected by vegetation fraction over the Sahelian and Sudanian regions while sensible heat fluxes are more impacted over the Guinea Coast and Sudanian Sahel. Also, in MV‐V simulation there is an increase in evapotranspiration mainly over the Sahel and some specific areas in Guinea Coast from June to September. Moreover, it is noticed that high near‐surface temperature is associated with a weak vegetation fraction, especially during May and June. Finally, varying vegetation seems to improve the simulation of surface energy fluxes and in turn impact on climate parameters. This suggests that climate modelers should prioritize the use of varying vegetation options to improve the representation of the West African climate system.
Comparison between the use of varying vegetation fraction and fix vegetation fraction in regional climate models over West Africa: Case study of the Unified Model with focus on three different climatic zones.
Abstract Worldwide, the most important concern in the treatment of sexually transmitted infections is the increase in antimicrobial resistant Neisseria gonorrhoeae strains including resistance to ...cephalosporins, penicillins, fluoroquinolones or macrolides. To investigate the trends of antimicrobial susceptibility among N. gonorrhoeae strains isolated from male patients with urethritis, a Japanese surveillance committee conducted the second nationwide surveillance study. Urethral discharge was collected from male patients with urethritis at 26 medical facilities from March 2012 to January 2013. Of the 151 specimens, 103 N. gonorrhoeae strains were tested for susceptibility to 20 antimicrobial agents. None of the strains was resistant to ceftriaxone, but the minimum inhibitory concentration (MIC) 90% of ceftriaxone increased to 0.125 μg/ml, and 11 (10.7%) strains were considered less susceptible with an MIC of 0.125 μg/ml. There were 11 strains resistant to cefixime, and the MICs of these strains were 0.5 μg/ml. The distributions of the MICs of fluoroquinolones, such as ciprofloxacin, levofloxacin and tosufloxacin, were bimodal. Sitafloxacin, a fluoroquinolone, showed strong activity against all strains, including strains resistant to other three fluoroquinolones, such as ciprofloxacin, levofloxacin and tosufloxacin. The azithromycin MICs in 2 strains were 1 μg/ml.
Abstract Although muscular dystrophy patients often have feeding difficulty and need long-term enteral nutrition, only a few reports have described gastrostomy feeding in these patients. This study ...was designed to evaluate the efficacy and tolerance of gastrostomy feeding in patients with muscular dystrophy. We performed a retrospective, multicenter study on 144 patients with muscular dystrophy who received gastrostomy feeding between 2007 and 2009 in 25 neuromuscular centers in Japan. There were 77 Duchenne muscular dystrophy (median age at gastrostomy placement 26 years, range 13–47 years), 40 myotonic dystrophy (median age 54.5 years, range 13–70 years), 11 Fukuyama congenital muscular dystrophy (median age 22 years, range 13–29 years), 5 limb girdle muscular dystrophy (median age 62 years, range 43–78 years), and 5 facioscapulohumeral muscular dystrophy (median age 52 years, range 28–67 years) patients. Many benefits including amelioration of malnutrition, swallowing difficulty and respiratory status were observed after the introduction of gastrostomy feeding. Especially in patients with Duchenne muscular dystrophy, mean body weight significantly increased after gastrostomy placement. Although most complications, which are commonly observed in other populations, were tolerable, respiratory failure and peritonitis were important concerns. These findings suggest that gastrostomy placement at an appropriate time is advisable in patients with muscular dystrophy.
Abstract Genital chlamydial infection is a principal sexually transmitted infection worldwide. Chlamydia trachomatis can cause male urethritis, acute epididymitis, cervicitis, and pelvic inflammatory ...disease as sexually transmitted infections. Fortunately, homotypic resistant C. trachomatis strains have not been isolated to date; however, several studies have reported the isolation of heterotypic resistant strains from patients. In this surveillance study, clinical urethral discharge specimens were collected from patients with urethritis in 51 hospitals and clinics in 2009 and 38 in 2012. Based on serial cultures, the minimum inhibitory concentration (MIC) could be determined for 19 isolates in 2009 and 39 in 2012. In 2009 and 2012, the MICs (MIC90 ) of ciprofloxacin, levofloxacin, tosufloxacin, sitafloxacin, doxycycline, minocycline, erythromycin, clarithromycin, and azithromycin were 2 μg/ml and 1 μg/ml, 0.5 μg/ml and 0.5 μg/ml, 0.125 μg/ml and 0.125 μg/ml, 0.063 μg/ml and 0.063 μg/ml, 0.125 μg/ml and 0.125 μg/ml, 0.125 μg/ml and 0.125 μg/ml, 0.016 μg/ml and 0.016 μg/ml, and 0.063 μg/ml and 0.063 μg/ml, respectively. In summary, this surveillance project did not identify any resistant strain against fluoroquinolone, tetracycline, or macrolide agents in Japan.
Simulation of absorbing aerosol indices for African dust Yoshioka, Masaru; Mahowald, Natalie; Dufresne, Jean-Louis ...
Journal of Geophysical Research - Atmospheres,
27 September 2005, Letnik:
110, Številka:
D18
Journal Article
Recenzirano
Odprti dostop
It has been speculated that the vegetation change and human land use have modulated the dust sources in North Africa and contributed to the observed increase of desert dust since 1960s. However, the ...roles of surface disturbances on dust generation are not well constrained because of limitations in the available data and models. This study addresses this issue by simulating the Total Ozone Mapping Spectrometer (TOMS) Absorbing Aerosol Indices (AAIs) for model‐predicted dust and comparing them with the observations. Model simulations are conducted for natural topographic depression sources with and without adding sources due to vegetation change and cultivation over North Africa. The simulated AAIs capture the previously reported properties of TOMS AAI as well as observed magnitude and spatial distribution reasonably well, although there are some important disagreements with observations. Statistical analyses of spatial and temporal patterns of simulated AAI suggest that simulations using only the natural topographic source capture the observed patterns better than those using 50% of surface disturbance sources. The AAI gradients between Sahara (north) and Sahel (south) suggest that the best mixture of surface disturbance sources is 20–25%, while spatial and temporal correlations suggest that the optimum mixture is 0–15% with the upper bound of 25–40%. However, sensitivity studies show that uncertainties associated with meteorology and source parameterization are large and may undermine the findings derived from the simulations. Additional uncertainties will arise because of model errors in sources, transport, and deposition. Such uncertainties in the model simulations need to be reduced in order to constrain the roles of different types of dust sources better using AAI simulation.
Abstract Neisseria gonorrhoeae is one of the most important pathogens causing sexually transmitted infection, and strains that are resistant to several antimicrobials are increasing. To investigate ...the trends of antimicrobial susceptibility among N. gonorrhoeae strains isolated from male patients with urethritis, a Japanese surveillance committee conducted the first nationwide surveillance. The urethral discharge was collected from male patients with urethritis at 51 medical facilities from April 2009 to October 2010. Of the 156 specimens, 83 N. gonorrhoeae strains were tested for susceptibility to 18 antimicrobial agents. The prevalence of β-lactamase-producing strains and chromosomally mediated resistant strains were 7.2 % and 16.5 %, respectively. None of the strains was resistant to ceftriaxone, but the minimum inhibitory concentration (MIC) of ceftriaxone for 7 strains (8.4 %) was 0.125 μg/ml. One strain was resistant to cefixime (MIC 0.5 μg/ml). The MICs of fluoroquinolones, such as ciprofloxacin, levofloxacin, and tosufloxacin, showed a bimodal distribution. The MIC of sitafloxacin was lower than those of the three fluoroquinolones listed here, and it was found that the antimicrobial activity of sitafloxacin was stronger than that of the fluoroquinolones. The MIC of azithromycin in 2 strains was 2 μg/ml, but no high-level resistance to macrolides was detected.
A total of 16 global chemistry transport models and general circulation models have participated in this study; 14 models have been evaluated with regard to their ability to reproduce the ...near-surface observed number concentration of aerosol particles and cloud condensation nuclei (CCN), as well as derived cloud droplet number concentration (CDNC). Model results for the period 2011-2015 are compared with aerosol measurements (aerosol particle number, CCN and aerosol particle composition in the submicron fraction) from nine surface stations located in Europe and Japan. The evaluation focuses on the ability of models to simulate the average across time state in diverse environments and on the seasonal and short-term variability in the aerosol properties. There is no single model that systematically performs best across all environments represented by the observations. Models tend to underestimate the observed aerosol particle and CCN number concentrations, with average normalized mean bias (NMB) of all models and for all stations, where data are available, of -24% and -35% for particles with dry diameters > 50 and > 120nm, as well as -36% and -34% for CCN at supersaturations of 0.2% and 1.0%, respectively. However, they seem to behave differently for particles activating at very low supersaturations (< 0.1%) than at higher ones. A total of 15 models have been used to produce ensemble annual median distributions of relevant parameters. The model diversity (defined as the ratio of standard deviation to mean) is up to about 3 for simulated N3 (number concentration of particles with dry diameters larger than 3 nm) and up to about 1 for simulated CCN in the extra-polar regions. A global mean reduction of a factor of about 2 is found in the model diversity for CCN at a supersaturation of 0.2% (CCN(0.2)) compared to that for N3, maximizing over regions where new particle formation is important. An additional model has been used to investigate potential causes of model diversity in CCN and bias compared to the observations by performing a perturbed parameter ensemble (PPE) accounting for uncertainties in 26 aerosol-related model input parameters. This PPE suggests that biogenic secondary organic aerosol formation and the hygroscopic properties of the organic material are likely to be the major sources of CCN uncertainty in summer, with dry deposition and cloud processing being dominant in winter. Models capture the relative amplitude of the seasonal variability of the aerosol particle number concentration for all studied particle sizes with available observations (dry diameters larger than 50, 80 and 120nm). The short-term persistence time (on the order of a few days) of CCN concentrations, which is a measure of aerosol dynamic behavior in the models, is underestimated on average by the models by 40% during winter and 20% in summer.
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