6,526 research outputs found
Next generation sequencing reveals the complete plastome sequence of newly discovered cliff-dwelling Sonchus boulosii (Asteraceae: Cichorieae) in Morocco
The complete chloroplast genome sequences of newly discovered cliff-dwelling species of Sonchus, S. boulosii, were reported in this study. The S. boulosii plastome was 152,016 bp long, with the large single copy (LSC) region of 83,988 bp, the small single copy (SSC) region of 18,566 bp, and two inverted repeat (IR) regions of 24,731 bp. The plastome contained 130 genes, including 88 protein-coding, six ribosomal RNA, and 36 transfer RNA genes. The overall GC content was 31.2%. Phylogenetic analysis of 12 representative plastomes within the order Cichorieae suggests that S. boulosii is closely related to S. oleraceus.National Research Foundation of Korea [NRF-2016R1D1A2B03934596
Naphthalimide Trifluoroacetyl Acetonate: A Hydrazine-Selective Chemodosimetric Sensor
The trifluoroacetyl acetonate naphthalimide derivative 1 has been synthesized in good yield. In acetonitrile solution, compound 1 reacts selectively with hydrazine (NH2NH2) to give a five-membered ring. This leads to OFF-ON fluorescence with a maximum intensity at 501 nm as well as easily discernible color changes. Based on a readily discernible and reproducible 3.9% change in overall fluorescence intensity, the limit of detection for 1 is 3.2 ppb (0.1 mu M), which is below the accepted limit for hydrazine set by the U.S. Environmental Protection Agency (EPA). Compound 1 is selective for hydrazine over other amines, including NH4OH, NH2OH, ethylenediamine, methylamine, n-butylamine, piperazine, dimethylamine, triethylamine, pyridine, and is not perturbed by environmentally abundant metal ions. When supported on glass-backed silica gel TLC plates, compound 1 acts as a fluorimetric and colorimetric probe for hydrazine vapor at a partial pressure of 9.0 mm Hg, with selectivity over other potentially interfering volatile analytes, including ammonia, methylamine, n-butylamine, formaldehyde, acetaldehyde, H2O2, HCl, and CO2 being observed. Probe 1 can also be used for the detection of hydrazine in HeLa cells and does so without appreciable interference from other biologically abundant amines and metal ions.U.S. National Science Foundation CHE-1057904Robert A. Welch Foundation F-1018CRI project grant from National Research Foundation of Korea (NRF)Korea government (MSIP) 2009-0081566Chemistr
Teachers’ Monitoring and Schools’ Performance: Evidence from Public Schools in Pakistan
This paper evaluates the impact of an innovative monitoring system on teacher attendance and school performance in Pakistan. In 2014, the government in Khyber Pakhtunkhwa province introduced the Independent Monitoring Project aiming at increasing teacher attendance in primary and secondary public schools by distributing to the government-hired monitors smart phones with a special data collection software installed. Our analysis is based on a difference-in-differences approach using the country wide Annual Status of Education Report from 2012 to 2016. Our findings suggest that monitoring of government schools has increased teacher attendance by 7.5 percentage points in the first year of intervention. But the positive effect wears off to 2.7 percentage points in the second year. Child attendance and test scores also increased in the first year, but in the second year they disappeared. Especially, in the first year, the monitoring system improved students’ math, reading, and English test scores by 0.13, 0.14, and 0.15 standard deviation, respectively, if they are grades 1-5. This result suggests that teacher attendance has an important role in delivering better student outcomes, but that monitoring should be coupled with appropriate incentive mechanism in order to have a lasting impact
On the Relationship between Spring NAO and Snowmelt in the Upper Southwestern United States
This study examines the relationship between the North Atlantic Oscillation (NAO) and snowmelt in spring in the upper southwestern states of the United States (UP_SW) including California, Nevada, Utah, and Colorado, using SNOTEL datasets for 34 yr (1980–2014). Statistically significant negative correlations are found between NAO averages in the snowmelt period and timings of snowmelt (i.e., positive NAO phases in spring enhance snowmelt, and vice versa). It is also found that correlations between El Niño–Southern Oscillation and snowmelt are negligible in the region. The NAO–snowmelt relationship is most pronounced below the 2800-m level; above this level, the relationship becomes weaker. The underlying mechanism for this link is that a positioning of upper-tropospheric anticyclonic (cyclonic) circulations over the western United States that are associated with development of the positive (negative) NAO phases tends to bring warmer and drier (colder and wetter) spring weather conditions to the region. The temperature variations related with the NAO phases also strongly modulate the snowfall–rainfall partitioning. The relationship between the NAO and spring snowmelt can serve as key information for the warm season water resources management in the UP_SW
On the Relationship Between the North Atlantic Oscillation and Early Warm Season Temperatures in the Southwestern United States
It is reported herein that the North Atlantic Oscillation (NAO), which has been known to directly affect winter weather conditions in western Europe and the eastern United States, is also linked to surface air temperature over the broad southwestern U.S. (SWUS) region, encompassing California, Nevada, Arizona, New Mexico, Utah, and Colorado, in the early warm season. The authors have performed monthly time-scale correlations and composite analyses using three different multidecadal temperature datasets. Results from these analyses reveal that NAO-related upstream circulation positively affects not only the means, but also the extremes, of the daily maximum and minimum temperatures in the SWUS. This NAO effect is primarily linked with the positioning of upper-tropospheric anticyclones over the western United States that are associated with development of the positive NAO phase through changes in lower-tropospheric wind directions as well as suppression of precipitation and enhanced shortwave radiation at the surface. The effect is observed in the SWUS only during the March–June period because the monthly migration of anticyclones over the western United States follows the migration of the NAO center over the subtropical Atlantic Ocean. The link between the SWUS temperatures and NAO has been strengthened in the last 30-yr period (1980–2009), compared to the previous 30-yr period (1950–79). In contrast to the NAO–SWUS temperature relationship, El Niño–Southern Oscillation (ENSO) and the Pacific decadal oscillation (PDO) show only marginal correlation strengths in several limited regions for the same 60-yr period
Progression of Impending Central Retinal Vein Occlusion to the Ischemic Variant Following Intravitreal Bevacizumab
A 60-year-old woman who had experienced two episodes of amaurosis fugax in her right eye presented with vision loss. Two weeks earlier, at a private clinic, she was diagnosed with impending central retinal vein occlusion (CRVO) of the right eye and received an intravitreal injection of bevacizumab. Two weeks after this injection she was diagnosed with ischemic CRVO. At 11-weeks post-presentation, extremely ischemic features were observed with fluorescein angiographic findings of severe vascular attenuation and extensive retinal capillary obliteration. At 22-weeks post-presentation she was diagnosed with neovascular glaucoma; she experienced no visual improvement over the following several months
Regional Variations of Optimal Sowing Dates of Maize for the Southwestern U.S.
Sowing date (SD) is sensitive to regional climate characteristics; thus, it is critical to systematically examine the effects of SD on crop yields for various temperature regimes. We performed a sensitivity study of SD for maize in the southwestern U.S. using the regionally extended version of the Agricultural Production Systems sIMulator (APSIM) model. The model was run utilizing North American Regional Reanalysis at a 32 km resolution from 1991 to 2011, with an irrigation threshold at 95% of the soil water-holding capacity. Two types of SD optimizations maximizing yield potential (Yp), varying spatially or interannually, revealed that the optimal SD varies according to regional climate characteristics and depends on the base temperature climatology during the growing season. For cool regions at high elevations (e.g., northern California and northern Nevada) and in coastal areas, earlier sowing results in higher Yp, allowing longer growing seasons. In these regions, yearly varying of SD to reduce the negative effects of springtime cold events can also enhance Yp significantly. In low-elevation warm regions (e.g., southern Central Valley, southern California, and southwestern Arizona), the length of the growing season rarely impacts Yp, and early planting is crucial to avoid adverse impacts of extremely hot conditions in the summer. For transitional regions (e.g., the southern Great Basin in Nevada and the Colorado River basin in Arizona), high Yp can be obtained in a short growing season due to the optimal temperature range of the growing season. Thus, for the transitional regions, SD optimization does not have much impact on Yp
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