Surveying the Precautionary Principle\u27s Ongoing Global Development: The Evolution of an Emergent Environmental Management Tool

The precautionary principle, which many trace back to German regulations promulgated in the early 1970s, has developed into an important environmental management tool. Its inclusion in numerous international treaties and agreements over the past seventeen years con­firms its significance. Beyond international treaties, many foreign governments have explored the application of the precautionary principle to their own decisionmaking procedures. For instance, the precautionary principle has been the central focus of judicial decisions in Australia, Canada, and India. Despite this growing global acceptance and implementation of the precautionary principle, the United States has remained adamantly opposed to its introduction into domestic policy. This Note focuses on international application or non-application of the precautionary principle in order to better understand the United States’ current opposition. Ultimately, this comparative analysis should clarify, which, if any, governmental avenue will prove most effective in laying the foundation for implementation of the precautionary principle in this country

Isomerization Mechanism in Hydrazone-Based Rotary Switches: Lateral Shift, Rotation, or Tautomerization?

Two intramolecularly hydrogen-bonded arylhydrazone (aryl = phenyl or naphthyl) molecular switches have been synthesized, and their full and reversible switching between the E and Z configurations have been demonstrated. These chemically controlled configurational rotary switches exist primarily as the E isomer at equilibrium and can be switched to the protonated Z configuration (Z-H^+) by the addition of trifluoroacetic acid. The protonation of the pyridine moiety in the switch induces a rotation around the hydrazone C═N double bond, leading to isomerization. Treating Z-H^+ with base (K_(2)CO_3) yields a mixture of E and “metastable” Z isomers. The latter thermally equilibrates to reinstate the initial isomer ratio. The rate of the Z → E isomerization process showed small changes as a function of solvent polarity, indicating that the isomerization might be going through the inversion mechanism (nonpolar transition state). However, the plot of the logarithm of the rate constant k vs the Dimroth parameter (E_T) gave a linear fit, demonstrating the involvement of a polar transition state (rotation mechanism). These two seemingly contradicting kinetic data were not enough to determine whether the isomerization mechanism goes through the rotation or inversion pathways. The highly negative entropy values obtained for both the forward (E → Z-H^+) and backward (Z → E) processes strongly suggest that the isomerization involves a polarized transition state that is highly organized (possibly involving a high degree of solvent organization), and hence it proceeds via a rotation mechanism as opposed to inversion. Computations of the Z ↔ E isomerization using density functional theory (DFT) at the M06/cc-pVTZ level and natural bond orbital (NBO) wave function analyses have shown that the favorable isomerization mechanism in these hydrogen-bonded systems is hydrazone–azo tautomerization followed by rotation around a C–N single bond, as opposed to the more common rotation mechanism around the C═N double bond

CFD Model Analysis and Validation for a Formula SAE Racecar

This project examines the computational fluid dynamics (CFD) model used by Global Formula Racing (GFR) to simulate external aerodynamics for a Formula SAE racecar. It seeks to improve the accuracy of the existing model by changing mesh and physics model parameters. Accuracy of the model is quantified through comparison to physical experimental data. Mesh parameters studied include prism layer properties, wake refinement, and volumetric control use. Multiple turbulence models are compared, and sensitivity to initial conditions and boundary conditions is quantified. A recommended half-car mesh and physics model is produced, and recommendations for further development are added

Characteristics and outcome of severe hypercalcemia on admission to the emergency department: a retrospective cohort study.

AIMS OF THE STUDY To investigate the prevalence of hypercalcemia (>2.60 mmol/l) and severe hypercalcemia (≥2.80 mmol/l) on admission. Symptoms, causes, course of serum calcium, treatment and outcome of severe hypercalcemia were evaluated and compared to historical data from previous studies. METHODS In this retrospective cohort study, all patients presenting to the interdisciplinary emergency department of the Buergerspital Solothurn between 01 January 2017 and 31 December 2020 with measurements of serum calcium were included. Chart reviews were performed for patients with calcium ≥2.80 mmol/l to assess clinical presentation, course of disease and treatment for severe hypercalcemia. RESULTS Of 31,963 tested patients, 869 patients (2.7%) had hypercalcemia on the admission, of which 161 had severe hypercalcemia. Non-albumin corrected calcium was 3.07 (0.32) while albumin corrected calcium was 3.34 (0.44). Calcium was higher in patients with malignancy-related hypercalcemia (3.18 [0.34] versus 3.00 [0.3], p <0.001). Neuropsychiatric (35%) and gastrointestinal (24%) were the leading symptoms. Malignancy was the most common identifiable cause of hypercalcemia (40%), with lung cancer (20%), multiple myeloma (14%) and renal cell carcinoma (11%) being the main cancer types. 36% of patients with severe hypercalcemia took calcium supplements. Bisphosphonate treatment was an independent predictor of a fall in calcium until day 5 (regression coefficient: -0.404, standard error 0.11, p <0.001). Hypercalcemia was not mentioned in the final discharge report in 38% of cases. CONCLUSION Severe hypercalcemia is common and malignancy-related in almost half of the cases. Neuropsychiatric and gastrointestinal symptoms were most prevalent. Awareness of hypercalcemia, particularly in cancer patients and those with known triggering factors, should be raised in order to identify and treat this harmful disorder early

Measurement of atmospheric nitrous acid at Blodgett Forest during BEARPEX2007

Nitrous acid (HONO) is an important precursor of the hydroxyl radical (OH) in the lower troposphere. Understanding HONO chemistry, particularly its sources and contribution to HO_x (=OH+HO_2) production, is very important for understanding atmospheric oxidation processes. A highly sensitive instrument for detecting atmospheric HONO based on wet chemistry followed by liquid waveguide long path absorption photometry was deployed in the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) at Blodgett Forest, California in late summer 2007. The median diurnal variation shows minimum HONO levels of about 20–30 pptv during the day and maximum levels of about 60–70 pptv at night, a diurnal pattern quite different from the results at various other forested sites. Measured HONO/NO_2 ratios for a 24-h period ranged from 0.05 to 0.13 with a mean ratio of 0.07. Speciation of reactive nitrogen compounds (NO_y) indicates that HONO accounted for only ~3% of total NO_y. However, due to the fast HONO loss through photolysis, a strong HONO source (1.59 ppbv day^(−1)) existed in this environment in order to sustain the observed HONO levels, indicating the significant role of HONO in NO_y cycling. The wet chemistry HONO measurements were compared to the HONO measurements made with a Chemical Ionization Mass Spectrometer (CIMS) over a three-day period. Good agreement was obtained between the measurements from the two different techniques. Using the expansive suite of photochemical and meteorological measurements, the contribution of HONO photolysis to HO_x budget was calculated to be relatively small (6%) compared to results from other forested sites. The lower HONO mixing ratio and thus its smaller contribution to HO_x production are attributed to the unique meteorological conditions and low acid precipitation at Blodgett Forest. Further studies of HONO in this kind of environment are needed to test this hypothesis and to improve our understanding of atmospheric oxidation and nitrogen budget

Mission San Jose Well Initiative

The objective of this community base project is to develop an irrigation system for a community garden that is sustainable and watered by one of the three wells on the Dominican Sisters\u27 Convent property located in Fremont, California. The overall goal of this project is to have a submersible solar powered pump, which will pump water to a tank that will store water and function on a timer. This tank will then deliver water to the community garden as well as other areas on the property. This project focuses on both an environmental and water resources aspects of design work. The design aims to fulfill the customer needs based on budget, functionality and location

Thyrotoxicosis in a 13-year-old girl following pituitary adenectomy for Cushing's disease.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked FilesOur objective is to report a case of thyrotoxicosis following pituitary adenectomy for Cushing's disease, the only pediatric case to our knowledge. No thyroid antibodies were detected, and the thyrotoxicosis was successfully treated for 3 months with no relapse after 5 years of follow-up. The cause of thyrotoxicosis remains unknown

Measurement of atmospheric nitrous acid at Bodgett Forest during BEARPEX2007

Nitrous acid (HONO) is an important precursor of the hydroxyl radical (OH) in the lower troposphere. Understanding HONO chemistry, particularly its sources and contribution to HO&lt;sub&gt;x&lt;/sub&gt; (=OH+HO&lt;sub&gt;2&lt;/sub&gt;) production, is very important for understanding atmospheric oxidation processes. A highly sensitive instrument for detecting atmospheric HONO based on wet chemistry followed by liquid waveguide long path absorption photometry was deployed in the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) at Blodgett Forest, California in late summer 2007. The median diurnal variation shows minimum HONO levels of about 20–30 pptv during the day and maximum levels of about 60–70 pptv at night, a diurnal pattern quite different from the results at various other forested sites. Measured HONO/NO&lt;sub&gt;2&lt;/sub&gt; ratios for a 24-h period ranged from 0.05 to 0.13 with a mean ratio of 0.07. Speciation of reactive nitrogen compounds (NO&lt;sub&gt;y&lt;/sub&gt;) indicates that HONO accounted for only ~3% of total NO&lt;sub&gt;y&lt;/sub&gt;. However, due to the fast HONO loss through photolysis, a strong HONO source (1.59 ppbv day&lt;sup&gt;−1&lt;/sup&gt;) existed in this environment in order to sustain the observed HONO levels, indicating the significant role of HONO in NO&lt;sub&gt;y&lt;/sub&gt; cycling. The wet chemistry HONO measurements were compared to the HONO measurements made with a Chemical Ionization Mass Spectrometer (CIMS) over a three-day period. Good agreement was obtained between the measurements from the two different techniques. Using the expansive suite of photochemical and meteorological measurements, the contribution of HONO photolysis to HO&lt;sub&gt;x&lt;/sub&gt; budget was calculated to be relatively small (6%) compared to results from other forested sites. The lower HONO mixing ratio and thus its smaller contribution to HO&lt;sub&gt;x&lt;/sub&gt; production are attributed to the unique meteorological conditions and low acid precipitation at Blodgett Forest. Further studies of HONO in this kind of environment are needed to test this hypothesis and to improve our understanding of atmospheric oxidation and nitrogen budget

Global Journalist: America's hunt for terrorists and Venezuela’s political crisis

On this December 19, 2002 program, journalists discuss a new U.S. order permitting the assassination of terrorists and a brewing political crisis Venezuela and what it means for global oil markets