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Current systems of conservation reserves may be insufficient to sustain biodiversity in the face of climate change and habitat losses. Consequently, calls have been made to protect Earth's remaining wildlands and complete the system of protected areas by establishing conservation reserves that (1) better represent ecosystems, (2) increase connectivity to facilitate biota movement in response to stressors including climate change, and (3) promote species persistence within intact landscapes. Using geospatial data, we conducted an assessment for expanding protected areas within the contiguous United States to include the least human-modified wildlands, establish a connected network, and better represent ecosystem diversity and hotspots of biodiversity. Our composite map highlights areas of high value to achieve these goals in the western United States, where existing protected areas and lands with high ecological integrity are concentrated. We also identified important areas in the East rich in species and containing ecosystems that are poorly represented in the existing protected area system. Expanding protection to these priority areas is ultimately expected to create a more resilient system for protecting the nation's biological heritage. This expectation should be subject to rigorous testing prior to implementation, and regional monitoring will ensure areas and actions are adjusted over time., (© 2017 by the Ecological Society of America.)

Conservation scientists emphasize the importance of maintaining a connected network of protected areas to prevent ecosystems and populations from becoming isolated, reduce the risk of extinction, and ultimately sustain biodiversity. Keeping protected areas connected in a network is increasingly recognized as a conservation priority in the current era of rapid climate change. Models that identify suitable linkages between core areas have been used to prioritize potentially important corridors for maintaining functional connectivity. Here, we identify the most "natural" (i.e., least human-modified) corridors between large protected areas in the contiguous Unites States. We aggregated results from multiple connectivity models to develop a composite map of corridors reflecting agreement of models run under different assumptions about how human modification of land may influence connectivity. To identify which land units are most important for sustaining structural connectivity, we used the composite map of corridors to evaluate connectivity priorities in two ways: (1) among land units outside of our pool of large core protected areas and (2) among units administratively protected as Inventoried Roadless (IRAs) or Wilderness Study Areas (WSAs). Corridor values varied substantially among classes of "unprotected" non-core land units, and land units of high connectivity value and priority represent diverse ownerships and existing levels of protections. We provide a ranking of IRAs and WSAs that should be prioritized for additional protection to maintain minimal human modification. Our results provide a coarse-scale assessment of connectivity priorities for maintaining a connected network of protected areas.

Learn how to recognize and respond to the danger signs and act immediately to help save his life. Trouble is looming when the largest artery in the body develops a bulge. According to the Society for Vascular Surgery, each year approximately 200,000 people in the United States are diagnosed with aortic aneurysm - a bulge or ballooning in the artery that leads from the heart. About 15,000 of these aneurysms are severe enough to rupture, creating an urgent situation with a high risk of death. Read on to learn how to protect a patient with a suspected or known aortic aneurysm.

Peripheral vascular diseases are being seen with increased frequency in the health care setting today. It is imperative that nurses have a clear understanding of arterial, venous, and lymphatic circulatory mechanisms as well as the pathophysiologic changes that accompany common diseases of these systems. Providing the ongoing assessment to obtain a diagnosis, establish the acute versus chronic nature of findings, monitor progression, plan care, and assess the response to treatment is an important role for the nurse in order to preserve function, life, and limb in these patients.

An inexpensive method is described which permits simultaneous quantification of the cerebrovascular extraction (E) of diffusion-limited compounds and cerebral blood flow (CBF) in rats. This method involves the use of two radioisotopic tracers: (a) a diffusion-limited, test tracer such as [3H]water; and (b) a reference tracer. The reference tracer is also used in the measurement of CBF. In the development and validation of this technique, results using two different types of reference tracers were compared. The reference tracers employed were: (a) [14C]butanol, a flow-limited (i.e. freely diffusible) compound; and (b) [141Ce]microspheres which embolize in the cerebromicrocirculation. Inclusion of [3H]water in the injection bolus permitted simultaneous measurement of Ew using both butanol and microspheres as the reference as well as concomitant measurement of CBF. Both tracers provided estimates of these values which behaved physiologically with respect to increasing arterial CO2 content (paCO2). In addition, the simultaneous measurement of Ew and CBF permitted calculation of the effective permeability of water across the blood-brain barrier (PwS) which was discovered to increased with increasing paCO2.

In the tetrabenazine (TBZ) model of depression, the cerebromicrocirculation was discovered to respond abnormally to metabolic demand as mimicked by the administration of CO2. Altered responsivity of cerebral blood flow and effective permeability of the blood--brain barrier to changes in PaCO2 were found. These physiologic defects coincided temporally with TBZ-induced depletion of central norepinephrine and dopamine and with the development of the behavioral effects of TBZ (the end points used to test the antidepressant potential of experimental drugs). Pretreatment with amitriptyline (a standard antidepressant and amine reuptake inhibitor) prevented the development of these TBZ-induced abnormalities in the cerebromicrocirculation, just as it prevented the behavioral effects.

The effects of amitriptyline, lithium, and electroconvulsive shock on cerebral permeability and blood flow were tested. These three treatments share in common (i) the ability to influence the functional activity of central adrenergic neurons by way of effects on the release, reuptake, or metabolism of norepinephrine and (ii) therapeutic efficacy in mood disturbances. Under control conditions, cerebral permeability increases linealy with increasing arterial partial pressure of carbon dioxide and hence cerebral blood flow. All three treatments altered this relationship in a manner consistent with their adrenergic effects. Amitriptyline potentiated this increase in cerebral permeability whereas lithium and electroconvulsive shock blunted this phenomenon. These results support the hypothesis that one function of central adrenergic neurons is regulation of the blood-brain barrier and raise the possibility that a related effect may underlie the clinical usefulness of such treatment.

The cerebromicrocirculation in the tetrabenzaine (TBZ) model of depression has been found to be abnormal with respect to (1) responsiveness of cerebral blood flow to increases in arterial CO2 content and (2) the effective permeability of the blood-brain barrier to water. Development of these abnormalities temporally paralleled the behavioral disturbances and catecholamine depletion induced by TBZ. These TBZ-induced changes occurred globally throughout the brain, being apparent in the forebrain, cerebellum, and medulla-pons. Pretreatment with the antidepressant amitriptyline prevented both behavioral and physiological effects of TBZ, whereas amitriptyline administered after TBZ was less effective. The results suggest that an important action of tricyclic antidepressants may be cerebromicrocirculatory effects.

All tricyclic antidepressants increase the degree of equilibration of [3H]water across the cerebral capillary (Ew) as measured by a dual-label radioactive tracer technique. By using amitriptyline (AMI) as a prototype, a series of studies was conducted to determine the mechanism for this drug effect. The AMI-induced increase in Ew was blocked by 6-hydroxydopamine ablation of central aminergic neurons and by pretreatment with phenoxybenzamine, an alpha adrenergic antagonist. Pretreatment with propranolol, a beta adrenergic antagonist, did not block the AMI-induced increase. Central serotonergic ablation by p-chloroamphetamine had no effect on the AMI-induced increase. Treatment with atropine and hydroxyzine separately also did not alter Ew. Based on these results, the AMI-induced increase in Ew appears to be mediated by the effect of the drug on central adrenergic neurons. The serotonergic, anticholinergic and antihistaminergic actions of AMI, by themselves, do not appear to play a role in this phenomenon. The results are compatible with the concept that the central adrenergic system functions, in part, to regulate the cerebromicrocirculation.