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Time-shifted television can time-shift advertising. This study explores the frequency and timing of digital video recorder (DVR) advertising views in a sample of 2015–2016 drama, reality, and sports programs. Although the majority of recorded advertisements are “zipped” (fast-forwarded), some programs have many DVR viewers and delayed normal-speed advertisement exposures. The number and shelf life of recorded advertisement views vary by genre. DVRs accounted for more than 25 percent of all advertisement views from dramas (15 percent day-shifted, 5 percent shifted by more than three days). Time-sensitive advertisements might appear in sport or reality programs with fewer delayed views.

Aquifer restoration in the United States is recognized as a technically challenging objective when dense non-aqueous phase liquids (DNAPLs) are present (1). In fact, only a few aquifers impacted by DNAPLs have been restored. Factors that have typically contributed to the lack of successful aquifer restoration include the chemical properties of the DNAPL, the physical properties of the aquifer, the absence of cost-effective technologies, and an incomplete or inaccurate development of a conceptual hydrogeological model for the site. In Latin America, environmental studies historically have been related to biological quality of surface water and groundwater. Recently, the U.S. and Canada have experienced an increased influx of foreign students and professionals interested in studying specialized courses in environmental engineering, or participating in conferences. This exposure to current topics has strengthened the awareness of these professionals regarding groundwater contamination from gasoline-derived compounds and chlorinated solvents. As a result of this increased awareness, Latin American hydrogeologists and environmental regulators have been able to recognize the potential problems that could result from DNAPL spills that may impact groundwater and have learned to approach them using locally available technology and resources. A case study of such an example is presented below.

Hybrid fiber-based master-oscillator power amplifier system coupled with a Yb:SFAP power amplifier will produce 500mJ at 10Hz with 100:1 temporal contrast over 3-10ns and 300GHz spectrally shaped bandwidth allowing broadband amplification corrected for gain narrowing.

Millions of dollars are spent in the United States each year to design, construct, and operate systems intended to remediate groundwater impacted by dense non-aqueous phase liquids (DNAPLs), such as trichloroethlene (TCE) and tetrachloroethene (PCE), or light non-aqueous phase liquids (LNAPLs), such as gasoline, diesel, and jet fuel. However, several recent studies suggest that many of these groundwater remediation systems may operate for decades without restoring groundwater to background conditions. This paper examines the potential economic impacts of continuing the current regulatory approach to remediation of NAPL-contaminated aquifers versus considering regionally contaminated aquifers as large storage basins instead of pristine resources. Treating water at the point of extraction when needed, provides an equivalent benefit and may be more practical and cost effective than attempting to restore aquifers to background conditions at the point of contamination.

The Peruvian government's approach for environmental regulation of petroleum exploration and production activities is based on a sectoral model. The office for the hydrocarbon sub-sector establishes effluent limits specific to exploration and production, but other regulations, such as water quality standards to protect receiving waters could also apply. An evaluation of these norms and standards suggests that application of regulatory criteria on a case-by-case basis within a general environmental framework could also be considered.

Plato (c.427–347 bc) developed a sophisticated set of groundwater laws. In addition to laws on water conservation and water rights, Plato developed water pollution regulations, as quoted below. If anyone deliberately spoil someone else’s water supply, whether spring or reservoir, by poisons or excavations or theft, the injured party should take his case to the City Wardens and submit his estimate of the damage in writing. Anyone convicted of fouling water by magic poisons should, in addition to his fine, purify the spring or reservoir using whatever methods of purification the regulations of the expounders prescribe as appropriate to the circumstances and the individual involved. (Sauders, 1970)

Environmental damage associated with oil and gas production operations is typically caused by releases of crude oil, other hydrocarbons liquids, produced water, or naturally occurring radioactive materials. These releases may be associated with wells, tank batteries, pits, or the piping systems that transport oil, gas, and water within and from the lease. The damage caused by these releases may be visible, such as large salt scars from water tank overtopping, or less apparent, such as soil or groundwater contamination from a tank or pipeline leak. Oil production leases are often sold many times between the initial discovery and when the time production becomes uneconomical. Environmental restoration costs may not be significant if averaged over the life of the lease. When production stops, however, the last owner of record may face large capital costs related to decommissioning production facilities. This may include landowner litigation. As oil and gas fields advance in their life cycles, purchasers should be aware of the past operating history and potential environmental liabilities and use this knowledge in structuring the lease acquisition. An environmental assessment provides the information needed to protect purchasers from excessive liability.