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1.
Proc Natl Acad Sci U S A ; 116(37): 18378-18383, 2019 09 10.
Artículo en Inglés | MEDLINE | ID: mdl-31383753

RESUMEN

The community of species, human institutions, and human activities at a given location have been shaped by historical conditions (both mean and variability) at that location. Anthropogenic climate change is now adding strong trends on top of existing natural variability. These trends elevate the frequency of "surprises"-conditions that are unexpected based on recent history. Here, we show that the frequency of surprising ocean temperatures has increased even faster than expected based on recent temperature trends. Using a simple model of human adaptation, we show that these surprises will increasingly challenge natural modes of adaptation that rely on historical experience. We also show that warming rates are likely to shift natural communities toward generalist species, reducing their productivity and diversity. Our work demonstrates increasing benefits for individuals and institutions from betting that trends will continue, but this strategy represents a radical shift that will be difficult for many to make.


Asunto(s)
Cambio Climático , Océanos y Mares , Temperatura , Aclimatación , Adaptación Fisiológica , Calentamiento Global , Humanos , Modelos Teóricos
2.
Global Spine J ; 13(7): 1793-1802, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35227126

RESUMEN

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To compare outcomes of percutaneous pedicle screw fixation (PPSF) to open posterior stabilization (OPS) in spinal instability patients and minimal access separation surgery (MASS) to open posterior stabilization and decompression (OPSD) in metastatic spinal cord compression (MSCC) patients. METHODS: We analysed patients who underwent surgery for thoracolumbar metastatic spine disease (MSD) from Jan 2011 to Oct 2017. Patients were divided into minimally invasive spine surgery (MISS) and open spine surgery (OSS) groups. Spinal instability patients were treated with PPSF/OPS with pedicle screws. MSCC patients were treated with MASS/OPSD. Outcomes measured included intraoperative blood loss, operative time, duration of hospital stay and ASIA-score improvement. Time to initiate radiotherapy and perioperative surgical/non-surgical complications was recorded. Propensity scoring adjustment analysis was utilised to address heterogenicity of histological tumour subtypes. RESULTS: Of 200 eligible patients, 61 underwent MISS and 139 underwent OSS for MSD. There was no significant difference in baseline characteristics between MISS and OSS groups. In the MISS group, 28 (45.9%) patients were treated for spinal instability and 33 (54.1%) patients were treated for MSCC. In the OSS group, 15 (10.8%) patients were treated for spinal instability alone and 124 (89.2%) were treated for MSCC. Patients who underwent PPSF had significantly lower blood loss (95 mL vs 564 mL; P < .001) and surgical complication rates(P < .05) with shorter length of stay approaching significance (6 vs 19 days; P = .100) when compared to the OPS group. Patients who underwent MASS had significantly lower blood loss (602 mL vs 1008 mL) and shorter length of stay (10 vs 18 days; P = .098) vs the OPSD group. CONCLUSION: This study demonstrates the benefits of PPSF and MASS over OPS and OPSD for the treatment of MSD with spinal instability and MSCC, respectively.

3.
Sociol Methods Res ; 40(2): 211-239, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-22523436

RESUMEN

The authors consider processes on social networks that can potentially involve three factors: homophily, or the formation of social ties due to matching individual traits; social contagion, also known as social influence; and the causal effect of an individual's covariates on his or her behavior or other measurable responses. The authors show that generically, all of these are confounded with each other. Distinguishing them from one another requires strong assumptions on the parametrization of the social process or on the adequacy of the covariates used (or both). In particular the authors demonstrate, with simple examples, that asymmetries in regression coefficients cannot identify causal effects and that very simple models of imitation (a form of social contagion) can produce substantial correlations between an individual's enduring traits and his or her choices, even when there is no intrinsic affinity between them. The authors also suggest some possible constructive responses to these results.

4.
Fish Oceanogr ; 28(5): 532-566, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31598058

RESUMEN

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.

5.
Science ; 352(6284): 423, 2016 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-27102475

RESUMEN

Palmer et al and Swain et al suggest that our "extra mortality" time series is spurious. In response, we show that including temperature-dependent mortality improves abundance estimates and that warming waters reduce growth rates in Gulf of Maine cod. Far from being spurious, temperature effects on this stock are clear, and continuing to ignore them puts the stock in jeopardy.


Asunto(s)
Adaptación Fisiológica , Explotaciones Pesqueras , Gadus morhua/fisiología , Calentamiento Global , Animales
6.
Science ; 350(6262): 809-12, 2015 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-26516197

RESUMEN

Several studies have documented fish populations changing in response to long-term warming. Over the past decade, sea surface temperatures in the Gulf of Maine increased faster than 99% of the global ocean. The warming, which was related to a northward shift in the Gulf Stream and to changes in the Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation, led to reduced recruitment and increased mortality in the region's Atlantic cod (Gadus morhua) stock. Failure to recognize the impact of warming on cod contributed to overfishing. Recovery of this fishery depends on sound management, but the size of the stock depends on future temperature conditions. The experience in the Gulf of Maine highlights the need to incorporate environmental factors into resource management.


Asunto(s)
Adaptación Fisiológica , Explotaciones Pesqueras , Gadus morhua/fisiología , Calentamiento Global , Animales , Calor , Maine , Dinámica Poblacional
7.
Chem Commun (Camb) ; (3): 228-9, 2002 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-12120378

RESUMEN

Building block methodology from trifluoroethanol and ring-closing metathesis using a Fürstner modification of Grubbs' conditions allows the rapid synthesis of novel difluorinated cyclooctenones.

8.
Sci Total Environ ; 447: 255-66, 2013 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-23391892

RESUMEN

Routine monitoring along the coast of the Gulf of Maine (GoM) reveals shellfish toxicity nearly every summer, but at varying times, locations, and magnitudes. The responsible toxin is known to be produced by the dinoflagellate Alexandrium fundyense, yet there is little apparent association between Alexandrium abundance and shellfish toxicity. One possibility is that toxic cells are persistent in offshore areas and variability in shellfish toxicity is caused not by changes in overall abundance, but rather by variability in transport processes. Measurements of offshore Alexandrium biomass are scarce, so we bypass cell abundance as an explanatory variable and focus instead on the relations between shellfish toxicity and concurrent metrics of GoM meteorology, hydrology, and oceanography. While this yields over two decades (1985-2005) of data representing a variety of interannual conditions, the toxicity data are gappy in spatial and temporal coverage. We address this through a combination of parametric curve fitting and hierarchical cluster analysis to reveal eight archetypical modes of seasonal toxicity timing. Groups of locations are then formed that have similar interannual patterns in these archetypes. Finally, the interannual patterns within each group are related to available environmental metrics using classification trees. Results indicate that a weak cross-shore sea surface temperature (SST) gradient in the summer is the strongest correlate of shellfish toxicity, likely by signifying a hydrological connection between offshore Alexandrium populations and near-shore shellfish beds. High cumulative downwelling wind strength early in the season is revealed as a precursor consistent with this mechanism. Although previous studies suggest that alongshore transport is important in moving Alexandrium from the eastern to western GoM, alongshore SST gradient is not an important correlate of toxicity in our study. We conclude by discussing the implications of our results for designing efficient and effective shellfish monitoring programs along the GoM coast.


Asunto(s)
Dinoflagelados/fisiología , Dinoflagelados/patogenicidad , Conceptos Meteorológicos , Mariscos/parasitología , Mariscos/toxicidad , Animales , Análisis por Conglomerados , Eutrofización , Modelos Teóricos , Mytilus/parasitología , Reproducibilidad de los Resultados , Estaciones del Año , Intoxicación por Mariscos/parasitología
9.
J Plankton Res ; 32(10): 1355-1368, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20824042

RESUMEN

Increasing availability and extent of biological ocean time series (from both in situ and satellite data) have helped reveal significant phenological variability of marine plankton. The extent to which the range of this variability is modified as a result of climate change is of obvious importance. Here we summarize recent research results on phenology of both phytoplankton and zooplankton. We suggest directions to better quantify and monitor future plankton phenology shifts, including (i) examining the main mode of expected future changes (ecological shifts in timing and spatial distribution to accommodate fixed environmental niches vs. evolutionary adaptation of timing controls to maintain fixed biogeography and seasonality), (ii) broader understanding of phenology at the species and community level (e.g. for zooplankton beyond Calanus and for phytoplankton beyond chlorophyll), (iii) improving and diversifying statistical metrics for indexing timing and trophic synchrony and (iv) improved consideration of spatio-temporal scales and the Lagrangian nature of plankton assemblages to separate time from space changes.

10.
Surgery ; 143(1): 126-33, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18154940

RESUMEN

BACKGROUND: Ischemia-reperfusion injury of skeletal muscle is a common clinical and experimental problem. To date, there has been no uniform and reproducible method to assess the extent of histologic injury. In this study, we developed a novel statistical methodology for evaluating injury in individual myocytes and 3 distinct methods for the interpretation of this data. METHODS: C57/BL6 mice underwent 2 h of hindlimb ischemia followed by reperfusion for 3 (n = 11), 24 (n = 12), or 48 (n = 10) h. The gastrocnemius muscles were harvested, stained, and evaluated under microscopy. Standardized criteria were applied to score individual myocytes as healthy or injured, and injury score was expressed as injured fibers/total fibers %. Three methods of analyzing myocyte data were developed and evaluated with statistical Block-Random Sampling to determine the number of counted fibers required to represent accurately the total injury. The Full-Frame Counting, Fourfold Divided Counting, and Stratified Individual Counting methods differ in the random order in which fibers or microscopic fields are scored. RESULTS: The 3 methods were found to be statistically sound at all experimental time points. Using the Full-Frame, Fourfold, and Stratified methods, the maximum number of required fibers at all time points was 600, 300, and 100, respectively, to obtain an estimation of injury with a 95% confidence interval. CONCLUSIONS: These criteria and statistical methods for histologic evaluation of ischemia-reperfusion injury in skeletal muscle are accurate and reproducible. The Fourfold method is the most practical and technically efficient method of assessing injury. Such a quantitative, direct assessment of injury is important and will be useful for future studies.


Asunto(s)
Músculo Esquelético/irrigación sanguínea , Daño por Reperfusión/patología , Índice de Severidad de la Enfermedad , Animales , Miembro Posterior/irrigación sanguínea , Masculino , Métodos , Ratones , Ratones Endogámicos C57BL , Células Musculares/patología , Reproducibilidad de los Resultados , Factores de Tiempo
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