Propagation of endangered birds in US institutions: How much space is there?

Captive breeding is often touted as a way to preserve species disappearing in the wild. Zoos and related institutions have limited space for animals, however, and use of what space exists may be restricted by conflicting demands of entertainment, education, and propagation. Curators of US bird collections sponsored an analysis of space available for long-term captive management. Seventy-three collections responded to a survey, providing data on 3,174 exhibits and holding areas under their control. The most optimistic analysis indicates room for fewer than 141 long-term management programs. To use space resources optimally for conservation, there is a strong need to develop priorities within management groups. New models and strategies for using captive propagation as a short-term tool to bolster wild populations should be created. Immediate attention should be paid to the most effective and efficient ways of improving husbandry and management techniques for birds. © 1995 Wiley-Liss, Inc.     

Treatment planning systems dosimetry auditing project in Portugal

Background and purposeThe Medical Physics Division of the Portuguese Physics Society (DFM_SPF) in collaboration with the IAEA, carried out a national auditing project in radiotherapy, between September 2011 and April 2012. The objective of this audit was to ensure the optimal usage of treatment planning systems. The national results are presented in this paper.Material and methodsThe audit methodology simulated all steps of external beam radiotherapy workflow, from image acquisition to treatment planning and dose delivery. A thorax CIRS phantom lend by IAEA was used in 8 planning test-cases for photon beams corresponding to 15 measuring points (33 point dose results, including individual fields in multi-field test cases and 5 sum results) in different phantom materials covering a set of typical clinical delivery techniques in 3D Conformal Radiotherapy.ResultsAll 24 radiotherapy centers in Portugal have participated. 50 photon beams with energies 4–18 MV have been audited using 25 linear accelerators and 32 calculation algorithms.In general a very good consistency was observed for the same type of algorithm in all centres and for each beam quality.ConclusionsThe overall results confirmed that the national status of TPS calculations and dose delivery for 3D conformal radiotherapy is generally acceptable with no major causes for concern. This project contributed to the strengthening of the cooperation between the centres and professionals, paving the way to further national collaborations.     

WILL BIOMEDICAL ENHANCEMENTS UNDERMINE SOLIDARITY,RESPONSIBILITY, EQUALITY AND AUTONOMY?

Prominent thinkers such as Jurgen Habermas and Michael Sandel are warning that biomedical enhancements will undermine fundamental political values. Yet whether biomedical enhancements will undermine such values depends on how biomedical enhancements will function, how they will be administered and to whom. Since only few enhancements are obtainable, it is difficult to tell whether these predictions are sound. Nevertheless, such warnings are extremely valuable. As a society we must, at the very least, be aware of developments that could have harmful consequences. Indeed, if important values were to be jeopardized, we should take appropriate measures to protect them. This paper focuses on four central values: solidarity, personal responsibility, equality and autonomy. It delineates the conditions under which biomedical enhancements would undermine these values. It also details the circumstances under which these values would be unaffected by enhancements as well as those under which they would be promoted. Specifying these conditions is valuable; it would enable society to prepare appropriate ethical guidelines and policy responses in advance.     

Use of uniform shots for robust planning of mask-based treatment in Gamma Knife Icon

PurposeTo verify whether Icon automatic correction is robust in preserving plan quality.Materials/methodsAn end-to-end phantom was used to verify Icon’s correction accuracy qualitatively. For quantitative assessment, two plans, a composite- and a uniform-shot-only, were created for an elliptical- (E) and a sausage-shaped (S) lesion inside a PseudoPatient head phantom with a film insert. The phantom was irradiated in the planned and three other positions under each plan: 14° pitch (B); 14° rotation + 8° pitch (C); 95° rotation + 4-cm shift (D).ResultsIcon accurately corrects the locations of the shots. For the uniform-shot plans: all gamma index passing rates were >97%, and the differences between the planned and the delivery doses (minimum, maximum, and mean) were all ≤0.1 Gy. For the composite-shot plans, however, the dose differences increased as the phantom was shifted through positions B-D, with a gamma index passing rate of 61% for lesion-E in position D, and 92%, 79%, and 45% for lesion-S in positions B, C, and D, respectively.ConclusionsPlans using only uniform shots are more robust to deviations in treatment position. The tolerance for such deviations may be lower for plans using composite shots.     

Parallel movement planning is achieved via an optimal preparatory state in motor cortex

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Habitat availability for bottomland hardwood forest birds: the importance of considering elevation

ABSTRACT Estimating habitat availability at large spatial scales is critical for identifying conservation and management priorities for birds. Given the effects of patch size on habitat selection and productivity of many bird species, large‐scale approaches often focus on identifying and enumerating patches large enough to support sustainable populations. Declines in the availability of bottomland hardwood forests have made this approach imperative for species that depend on these forests. However, most remaining bottomland forests are relatively low‐elevation sites that were difficult to convert to agriculture. For species that require densely vegetated understories or well‐developed litter layers, such as Swainson's Warblers (Limnothlypis swainsonii), these relatively flood‐prone forests may not provide suitable habitat and, consequently, current prioritization methods may overestimate habitat availability. We examined the effect of elevation on estimates of habitat availability for Swainson's Warblers in a 65,000‐ha bottomland hardwood forest (White River National Wildlife Refuge) in eastern Arkansas. We detected Swainson's Warblers at 88 of 2222 sampled points, and Swainson's Warblers only used relatively high elevations in the refuge. Based on our estimates, about 25% of the refuge is at a suitable elevation for Swainson's Warblers. Without considering elevation, this refuge would support an estimated 7000 to 7600 pairs, but, when elevation is considered, the estimated number of pairs drops to 1500–2000 pairs. In reality, because of a lack of suitable seral stages at high elevations in the refuge, this area likely supports only 75–100 pairs. For Swainson's Warblers and other understory‐dependent bottomland species, elevation should be incorporated into conservation planning to obtain accurate estimates of habitat availability. In addition, management should be focused on these high‐elevation areas to maximize habitat availability for these species of concern.     

A new split arc VMAT technique for lymph node positive breast cancer

PurposeTo investigate different volumetric modulated arc therapy (VMAT) field designs for lymph node positive breast cancer patients when compared to conventional static fields and standard VMAT designs.MethodsNineteen breast cancer patients with lymph node involvement (eleven left and eight right sided) were retrospectively analyzed with different arc designs. Proposed split arc designs with total rotations of 2 × 190° and 2 × 240° were compared to conventional field in field (FinF) and previously published non-split arc techniques with the same amount of total rotations.ResultsAll VMAT plans were superior in dose conformity, when compared to the FinF plans. Split arc design decreased significantly ipsilateral lung dose and heart V5Gy for both left and right sided cases, when compared to non-split VMAT designs. For left sided cases no significant differences were seen in contralateral lung mean dose or V5Gy between different VMAT designs. For right sided cases the contralateral lung dose V5Gy was significantly higher in split VMAT group, when compared to non-split VMAT designs. The contralateral breast dose V5Gy increased significantly for split VMAT plans for both sides, when compared to non-split VMAT designs or FinF plans.ConclusionsThe proposed split VMAT technique was shown to be superior to previously published non-split VMAT and conventional FinF techniques significantly reducing dose to the ipsilateral lung and heart. However, this came with the expense of an increase in the dose to the contralateral breast and for right-sided cases to the contralateral lung.     

Hippocampal replay reflects specific past experiences rather than a plan for subsequent choice

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