Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.
--------
Question: Abstract: The population of common seal Phoca vitulina in the westernmost part of the Wadden Sea, The Netherlands, has collapsed during the past few decades. Between 1950 and 1975 the population dropped from more than 3,000 to less than 500 animals. Comparative studies of common seal populations from different parts of the Wadden Sea reveal that pup production has declined sharply only in the western (Dutch) part. A comparative toxicological study on the levels of heavy metals and organochlorines in tissues of seals from the western and northern parts of the Wadden Sea shows that only the polychlorinated biphenyl (PCB) levels differ significantly. This is predominantly a result of PCB pollution from the river Rhine, which mainly affects the western (Dutch) part. PCBs are thought to be responsible for the low rate of reproduction in Dutch common seals on the basis of epidemiological and experimental data on the ability of PCBs to interfere with mammalian reproduction. Here I report that reproductive failure in common seals from the Dutch Wadden Sea is related to feeding on fish from that polluted area. This is the first demonstration of a causal relationship between naturally occurring levels of pollutants and a physiological response in marine mammals.

Answer: Reproductive failure in common seals feeding on fish from polluted coastal waters [published erratum appears in Nature 1986 Dec 4-10;324(6096):418]

Question: Abstract: Two sets of equations have been proposed to estimate the convective or sensible (WCV) and the evaporative or insensible (WEV) respiratory heat exchanges. They are applicable both at sea-level barometric pressure with air breathing (SLA) and in hypo- or hyperbaria in both air (HA) and artificial (HAA) atmospheres. The only environmental parameters required are in SLA: the temperature (TI) and the partial pressure of water vapor of the inspired air (PIH2O); in HA: TI, PIH2O, and the actual barometric pressure (PB); and in HAA: IT, PIH2O, PB, the volumetric mass (rho mix), and the specific heat (cp mix) of the breathed gas mixture. When no physiological data are available the results are expressed in energy units per liter of pulmonary ventilation (WCV/V and WEV/V) in J X dm-3 BTPS. If the ventilation value (V) is known the results are obtained in units of power (W).

Answer: Computation of respiratory heat exchanges.

Question: Abstract: From December 1981 through August 1984, 24 patients with spinal cord compression syndrome due to epidural neoplasms were evaluated for radiotherapy with clinical examination, radiographs of the spine, and myelography. All plain films were reviewed, and mock radiotherapy fields designed using specific criteria for margins. The same patients were reviewed a second time considering the additional information provided by myelography. The initial treatment fields were found to be inadequate in 69% of the patients. Even in patients with discrete bony lesions, the results of myelography affected the treatment 45% of the time. A history of previous spinal irradiation significantly influenced port design in only 1 of the 7 patients who had received previous radiotherapy. Although invasive, myelography is essential in planning the treatment of spinal cord compression.

Answer:
Impact of myelography on the radiotherapeutic management of malignant spinal cord compression.