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141.
Context
In response to predominantly local and private approaches to landscape change, landscape ecologists should critically assess the multiscalar influences on landscape design.Objectives
This study develops a governance framework for Nassauer and Opdam’s “Design-in-Science” model. Its objective is to create an approach for examining hierarchical constraints on landscape design in order to investigate linkages among urban greening initiatives, patterns of landscape change, and the broader societal values driving those changes. It aims to provide an integrative and actionable approach for landscape sustainability science.Methods
This framework is examined through an ethnographic study of public policy processes surrounding the urban tree initiatives in Boston, MA; Philadelphia, PA; and Baltimore, MD.Results
These initiatives demonstrate the impact of political and economic decentralization on urban landscape patterns. Their collaborative governance approach incorporates diverse resources to implement programming at a fine-scale. The predominant tree giveaway program fragments the urban and regional forest.Conclusion
Spatial and temporal fragmentation undermines the long-term security of urban greening programs, and it suggests reconsideration of the role of state regimes in driving broad scale spatial planning.142.
Seventy-four heifers in four separate breeding groups were allocated into two treatment groups for oestrus synchronisation. Group 1 was given a combination of an initial injection of norgestomet and oestradiol valerate together with a norgestomet ear implant left in place for nine days. Group 2 was given two injections of the synthetic prostaglandin luprostiol 10 days apart. The animals in group 1 were artificially inseminated once 48 hours after the removal of the implant and those in group 2 were inseminated once 72 hours after the second injection of luprostiol. Subsequently any returns were rebred by either AI or natural service. There was no significant difference between the numbers of animals in the two treatment groups which were diagnosed pregnant 33 to 35 days after insemination, although the implant treatment gave a higher overall proportion of pregnancies (70 per cent, 51 per cent). It also gave significantly smaller numbers of 'open' days over the whole of the breeding period. A study of individual animals by progesterone assay and investigation of ovarian structures by real-time ultrasound showed that some of them had unusual progesterone profiles but nevertheless became pregnant. It would appear that a corpus luteum may be responsive to prostaglandins even though it is secreting only a low level of progesterone. 相似文献
143.
Elena M Finkbeiner Nathan J Bennett Timothy H Frawley Julia G Mason Dana K Briscoe Cassandra M Brooks Crystal A Ng Rosana Ourens Katherine Seto Shannon Switzer Swanson Jose Urteaga Larry B Crowder 《Fish and Fisheries》2017,18(6):1180-1191
Inaccurate or incomplete diagnosis of the root causes of overfishing can lead to misguided and ineffective fisheries policies and programmes. The “Malthusian overfishing narrative” suggests that overfishing is driven by too many fishers chasing too few fish and that fishing effort grows proportionately to human population growth, requiring policy interventions that reduce fisher access, the number of fishers, or the human population. By neglecting other drivers of overfishing that may be more directly related to fishing pressure and provide more tangible policy levers for achieving fisheries sustainability, Malthusian overfishing relegates blame to regions of the world with high population growth rates, while consumers, corporations and political systems responsible for these other mediating drivers remain unexamined. While social–ecological systems literature has provided alternatives to the Malthusian paradigm, its focus on institutions and organized social units often fails to address fundamental issues of power and politics that have inhibited the design and implementation of effective fisheries policy. Here, we apply a political ecology lens to unpack Malthusian overfishing and, relying upon insights derived from the social sciences, reconstruct the narrative incorporating four exemplar mediating drivers: technology and innovation, resource demand and distribution, marginalization and equity, and governance and management. We argue that a more nuanced understanding of such factors will lead to effective and equitable fisheries policies and programmes, by identifying a suite of policy levers designed to address the root causes of overfishing in diverse contexts. 相似文献
144.
Michelle D. Staudinger Katherine E. Mills Karen Stamieszkin Nicholas R. Record Christine A. Hudak Andrew Allyn Antony Diamond Kevin D. Friedland Walt Golet Meghan Elisabeth Henderson Christina M. Hernandez Thomas G. Huntington Rubao Ji Catherine L. Johnson David Samuel Johnson Adrian Jordaan John Kocik Yun Li Matthew Liebman Owen C. Nichols Daniel Pendleton R. Anne Richards Thomas Robben Andrew C. Thomas Harvey J. Walsh Keenan Yakola 《Fisheries Oceanography》2019,28(5):532-566
The timing of recurring biological and seasonal environmental events is changing on a global scale relative to temperature and other climate drivers. This study considers the Gulf of Maine ecosystem, a region of high social and ecological importance in the Northwest Atlantic Ocean and synthesizes current knowledge of (a) key seasonal processes, patterns, and events; (b) direct evidence for shifts in timing; (c) implications of phenological responses for linked ecological‐human systems; and (d) potential phenology‐focused adaptation strategies and actions. Twenty studies demonstrated shifts in timing of regional marine organisms and seasonal environmental events. The most common response was earlier timing, observed in spring onset, spring and winter hydrology, zooplankton abundance, occurrence of several larval fishes, and diadromous fish migrations. Later timing was documented for fall onset, reproduction and fledging in Atlantic puffins, spring and fall phytoplankton blooms, and occurrence of additional larval fishes. Changes in event duration generally increased and were detected in zooplankton peak abundance, early life history periods of macro‐invertebrates, and lobster fishery landings. Reduced duration was observed in winter–spring ice‐affected stream flows. Two studies projected phenological changes, both finding diapause duration would decrease in zooplankton under future climate scenarios. Phenological responses were species‐specific and varied depending on the environmental driver, spatial, and temporal scales evaluated. Overall, a wide range of baseline phenology and relevant modeling studies exist, yet surprisingly few document long‐term shifts. Results reveal a need for increased emphasis on phenological shifts in the Gulf of Maine and identify opportunities for future research and consideration of phenological changes in adaptation efforts. 相似文献
145.
146.
Katherine J. Bennett Reza Seddighi Kaitlin A. Moorhead Kristin Messenger Sherry K. Cox Xiaocun Sun Kirby Pasloske Bruno H. Pypendop Thomas J. Doherty 《Veterinary anaesthesia and analgesia》2019,46(2):173-181
Objective
To determine the effect of fentanyl on the induction dose and minimum infusion rate of alfaxalone required to prevent movement in response to a noxious stimulus (MIRNM) in dogs.Study design
Experimental crossover design.Animals
A group of six healthy, adult, intact female mixed-breed dogs, weighing 19.7 ± 1.3 kg.Methods
Dogs were randomly administered one of three treatments at weekly intervals: premedication with 0.9% saline (treatment A), fentanyl 5 μg kg–1 (treatment ALF) or fentanyl 10 μg kg–1 (treatment AHF), administered intravenously over 5 minutes. Anesthesia was induced 5 minutes later with incremental doses of alfaxalone to achieve intubation and was maintained for 90 minutes in A with alfaxalone (0.12 mg kg–1 minute–1), in ALF with alfaxalone (0.09 mg kg–1 minute–1) and fentanyl (0.1 μg kg–1 minute–1) and in AHF with alfaxalone (0.06 mg kg–1 minute–1) and fentanyl (0.2 μg kg–1 minute–1). The alfaxalone infusion was increased or decreased by 0.006 mg kg–1 minute–1 based on positive or negative response to antebrachium stimulation (50 V, 50 Hz, 10 ms). Data were analyzed using a mixed-model anova and presented as least squares means ± standard error.Results
Alfaxalone induction doses were 3.50 ± 0.13 (A), 2.17 ± 0.10 (ALF) and 1.67 ± 0.10 mg kg–1 (AHF) and differed among treatments (p < 0.05). Alfaxalone MIRNM was 0.17 ± 0.01 (A), 0.10 ± 0.01 (ALF) and 0.07 ± 0.01 mg kg–1 minute–1 (AHF) and differed among treatments. ALF and AHF decreased the MIRNM by 44 ± 8% and 62 ± 5%, respectively (p < 0.05). Plasma alfaxalone concentrations at MIRNM were 5.82 ± 0.48 (A), 4.40 ± 0.34 (ALF) and 2.28 ± 0.09 μg mL–1 (AHF).Conclusions and clinical relevance
Fentanyl, at the doses studied, significantly decreased the alfaxalone induction dose and MIRNM. 相似文献147.
Christopher M. Anderson Melissa J. Krigbaum Martin C. Arostegui Megan L. Feddern John Zachary Koehn Peter T. Kuriyama Christina Morrisett Caitlin I. Allen Akselrud Melanie J. Davis Courtney Fiamengo Ava Fuller Qi Lee Katherine N. McElroy Maite Pons Jessica Sanders 《Fish and Fisheries》2019,20(2):268-285
Wild capture fisheries produce 90 million tonnes of food each year and have the potential to provide sustainable livelihoods for nearly 40 million people around the world ( http://www.fao.org/3/a-i5555e.pdf ). After decades of overfishing since industrialization, many global fish stocks have recovered, a change brought about through effective management. We provide a synthetic overview of three approaches that managers use to sustain stocks: regulating catch and fishing mortality, regulating effort and regulating spatial access. Within each of these approaches, we describe common restrictions, how they alter incentives to change fishing behaviour, and the resultant ecological, economic and community‐level outcomes. For each approach, we present prominent case‐studies that illustrate behaviour and the corresponding performance. These case‐studies show that sustaining target stocks requires a hard limit on fishing mortality under most conditions, but that additional measures are required to generate economic benefits. Different systems for allocation allow stakeholder communities to strike a locally acceptable balance between profitability and employment. 相似文献
148.
149.
Interannual variability in the feeding and condition of subyearling Chinook salmon off Oregon and Washington in relation to fluctuating ocean conditions 下载免费PDF全文
Chinook salmon (Oncorhynchus tshawytscha) is one of several economically‐important species of salmon found in the Northeast Pacific Ocean. The first months at sea are believed to be the most critical for salmon survival, with the highest rate of mortality occurring during this period. In the present study, we examined interannual diet composition and body condition trends for late‐summer subyearling Chinook salmon caught off Oregon and Washington from 1998 to 2012. Interannual variability was observed in juvenile salmon diet composition by weight of prey consumed. Juvenile subyearling Chinook salmon were mainly piscivorous, with northern anchovy (Engraulis mordax) being especially important, making up half the diet by weight in some years. Annual diets clustered into two groups, primarily defined by their proportion of invertebrate prey (14% versus 39% on average). Diet composition was found to influence adult returns, with salmon from high‐invertebrate years returning in significantly larger numbers 2–3 yrs later. However, years that had high adult returns had overall lower stomach fullness and poorer body condition as juveniles, a counterintuitive result potentially driven by the enhanced survival of less fit individuals in better ocean conditions (top‐down effect). Ocean conditions in years with a higher percentage of invertebrates in salmon diets were significantly cooler from May to August, and bottom‐up processes may have led to a fall plankton community with a larger proportion of invertebrates. Our results suggest that the plankton community assemblage during this first fall may be critical in predicting adult returns of Chinook salmon in the Pacific Northwest. 相似文献
150.
The effect of storage on ammonia,cytokine, and chemokine concentrations in feline whole blood 下载免费PDF全文