Monthly Archives: May 2013

National Research Council workshop on inorganic arsenic, webcast

Click here to view the workshop below.

Inorganic Arsenic: Scientific
Considerations for Hazard Identification and Dose-Response

April 4, 2013 – 7:45am to 5:45pm ET

RESEARCH COUNCIL – 2101 Constitution Avenue, NW
Lecture Room – Washington,

Germany building coal-fired power plants to replace nuclear power

“Germany will this year start up more coal-fired power stations than at any time in the past 20 years as the country advances a plan to exit nuclear energy by 2022.”

“Chancellor Angela Merkel, who shut Germany’s oldest atomic reactors two years ago in response to the Fukushima disaster in Japan, is seeking to replace the remaining nuclear plants with renewable generators and efficient fossil-fired stations.”

Click here for full news article.

Infant fluorosis control by feeding patterns

Borinskaia EI, Davydov BN, Kushnir SM, Borinskiĭ IN, Mikin VM. [Risk and prevention of teeth fluorosis in infants by feeding pattern changes.] Stomatologiia (Mosk). 2013;92(2):57-59.  [Article in Russian]

Effect of fluorides in drinking water on fluorine content in breast milk, the food for infants of the 1-sty year of life, was investigated. On determining fluorine concentration in urine and its excretion, fluorine intake by the infants was calculated under various alternatives (breast, mixed and artificial) of feeding. It has been found the in mixed and especially in artificial feeding, fluorine intake by the infants acquires uncontrollable character exceeding several times the dose of fluorine intake with breast milk under natural feeding. That was predominantly fluorine of drinking water. Mathematical formula for calculation of fluorine content in the food cooked for feeding of infants was elaborated. A computer program was formed be means of which calculation, control and management of fluorine intake are carried out in feeding alteration.

CO2 increased global foliage cover

Randall J. Donohue, Michael L. Roderick, Tim R. McVicar, Graham D. Farquhar. CO2 fertilisation has increased maximum foliage cover across the globe’s warm, arid environments. Geophysical Research Letters. DOI: 10.1002/grl.50563

Satellite observations reveal a greening of the globe over recent decades. The role in this greening of the ‘CO2 fertilization’ effect – the enhancement of photosynthesis due to rising CO2 levels – is yet to be established. The direct CO2 effect on vegetation should be most clearly expressed in warm, arid environments where water is the dominant limit to vegetation growth. Using gas exchange theory, we predict that the 14% increase in atmospheric CO2 (1982–2010) led to a 5 to 10% increase in green foliage cover in warm, arid environments. Satellite observations, analysed to remove the effect of variations in rainfall, show that cover across these environments has increased by 11%. Our results confirm that the anticipated CO2 fertilization effect is occurring alongside ongoing anthropogenic perturbations to the carbon cycle and that the fertilisation effect is now a significant land surface process.

Click here for full paper (fee).

Drinking water fluoride influences female endocrine hormones

Hou JX, Yang YJ, Gong B, Li SH, Ding Z, Wen SB, Li SQ, Cheng XM, Cui LX, Ba Y. [The influence of high fluoride exposure in drinking water on endocrine hormone in female.] Zhonghua Yu Fang Yi Xue Za Zhi. 2013 Feb;47(2):142-146. [Article in Chinese]

OBJECTIVE: To explore the influence of water fluoride exposure on reproductive hormones in female.

METHODS: Cross-sectional study was conducted in seven villages of a county in Henan province by using simple random sampling including high fluoride area, defluoridation project area and control area on April, 2011 based on the preliminary study results of fluoride concentration in drinking water. Women who were born and growth or lived in the village at least 5 years and aged 18-48 years old were recruited using cluster sampling. They were divided into high fluoride group (HFG, 116 subjects), defluoridation project group (DFPG, 132 subjects) and control group (CG, 227 subjects) in accordance with the above areas. All subjects accepted questionnaire and physical checkup. Fasting blood and morning urine samples were collected. The concentration of fluoride in urine was determined by fluoride ion selective electrode method. The serum level of GnRH was detected using enzyme linked immunosorbent assay (ELISA). The serum level of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T), estradiol (E2) were determined by chemiluminesence immunoassay (CLIA).

RESULTS: The average age was (39.44 ± 7.34), (38.84 ± 8.03), (37.45 ± 7.70) years old in female from DFPG, HFG and CG respectively, there were no significant differences among the three groups (F = 3.02, P = 0.05). The urine fluoride levels were (1.34 ± 1.07), (2.59 ± 1.57), (0.92 ± 0.46) mg/ml in female from DFPG, HFG and CG respectively, there was a significant difference among three groups (F = 105.38, P < 0.01). No significant differences were observed of serum GnRH, LH, T, FSH and E2 among three groups in follicular phase (P > 0.05). The serum levels of E2 in Ovulatory period were 67.73, 58.09, 84.96 pg/ml in female from DFPG, HFG and CG respectively. It was lower in HFG than that in CG (H = 4.00, P < 0.05). The serum levels of T in Ovulatory period were 0.55, 0.45, 0.55 ng/ml in female from DFPG, HFG and CG respectively. It was lower in HFG than that in DFPG (H = 6.47, P < 0.05), but no significant difference was observed between HFG and CG (H = 2.41, P > 0.05). The serum levels of GnRH in Luteal phase were 24.09, 20.16, 23.50 ng/ml in female from DFPG, HFG and CG respectively. It was lower in HFG than that in DFPG (H = 14.14, P < 0.05) and CG (H = 12.53, P < 0.05). The serum level of E2 in luteal phase were 81.47, 64.60, 74.55 pg/ml in female from DFPG, HFG and CG respectively. It was lower in HFG than that in DFPG (H = 5.69, P < 0.05). As for LH, FSH and T, no significant differences were observed among the three groups (P > 0.05 respectively). The abnormal rates of E2 level were 22.73 (30/102), 37.93 (44/72), 20.26 (46/181) in female from DFPG, HFG and CG respectively. The E2 abnormal rate in female from HFG was higher that from DFPG (χ2 = 6.82, P < 0.05) and CG (χ2 = 12.38, P < 0.05).

CONCLUSION: Fluoride exposure may influence reproductive hormones in female, especially in ovulatory and luteal phase of menstrual cycle.

Solar activity affects cosmic rays, cloud formation, and climate

Ikuko Kitabaa,1, Masayuki Hyodoa, Shigehiro Katohb, David L. Dettmanc, and Hiroshi Satod. Midlatitude cooling caused by geomagnetic field minimum during polarity reversal. doi: 10.1073/pnas.1213389110
PNAS January 22, 2013 vol. 110 no. 4 1215-1220

The climatic effects of cloud formation induced by galactic cosmic rays (CRs) has recently become a topic of much discussion. The CR–cloud connection suggests that variations in geomagnetic field intensity could change climate through modulation of Cosmic Ray flux. This hypothesis, however, is not well-tested using robust geological evidence. Here we present paleoclimate and paleoenvironment records of five interglacial periods that include two geomagnetic polarity reversals. Marine oxygen isotope stages 19 and 31 contain both anomalous cooling intervals during the sea-level highstands and the Matuyama–Brunhes and Lower Jaramillo reversals, respectively. This contrasts strongly with the typical interglacial climate that has the temperature maximum at the sea-level peak. The cooling occurred when the field intensity dropped to 40% increase in Cosmic Ray flux. The climate warmed rapidly when field intensity recovered. We suggest that geomagnetic field intensity can influence global climate through the modulation of Cosmic Ray flux.

Click here for full paper (Open Source).

Carbon dioxide increases soybean productivity

Tracy E. Twine, Jarod J. Bryant, Katherine Richter, Carl J. Bernacchi, Kelly D. McConnaughay, Sherri J. Morris, Andrew D. B. Leakey. Impacts of elevated CO2 concentration on the productivity and surface energy budget of the soybean and maize agroecosystem in the Midwest U.S. Global Change Biology. doi: 10.1111/gcb.12270

The physiological response of vegetation to increasing atmospheric carbon dioxide concentration ([CO2]) modifies productivity and surface energy and water fluxes. Quantifying this response is required for assessments of future climate change. Many global climate models account for this response; however, significant uncertainty remains in model simulations of this vegetation response and its impacts. Data from in situ field experiments provide evidence that previous modeling studies may have overestimated the increase in productivity at elevated [CO2], and the impact on large-scale water cycling is largely unknown. We parameterized the Agro-IBIS dynamic global vegetation model with observations from the SoyFACE experiment to simulate the response of soybean and maize to an increase in [CO2] from 375 ppm to 550 ppm. The two key model parameters that were found to vary with [CO2] were the maximum carboxylation rate of photosynthesis and specific leaf area. Tests of the model that used SoyFACE parameter values showed a good fit to site-level data for all variables except latent heat flux over soybean and sensible heat flux over both crops. Simulations driven with historic climate data over the central U.S. showed that increased [CO2] resulted in decreased latent heat flux and increased sensible heat flux from both crops when averaged over 30 years. Thirty-year average soybean yield increased everywhere (~10%); however, there was no increase in maize yield except during dry years. Without accounting for CO2 effects on the maximum carboxylation rate of photosynthesis and specific leaf area, soybean simulations at 550 ppm overestimated leaf area and yield. Our results highlight important model parameter values that, if not modified in other models, could result in biases when projecting future crop-climate-water relationships.

Click here for full paper (fee).