Late Pleistocene and Holocene environmental history of the Iguala Valley, Central Balsas Watershed of Mexico

The origin of agriculture was a signal development in human affairs and as such has occupied the attention of scholars from the natural and social sciences for well over a century. Historical studies of climate and vegetation are closely associated with crop plant evolution because they can reveal the ecological contexts of plant domestication together with the antiquity and effects of agricultural practices on the environment. In this article, we present paleoecological evidence from three lakes and a swamp located in the Central Balsas watershed of tropical southwestern Mexico that date from 14,000 B.P. to the modern era. [Dates expressed in B.P. years are radiocarbon ages. Calibrated (calendar) ages, expressed as cal B.P., are provided for dates in the text.] Previous molecular studies suggest that maize (Zea mays L.) and other important crops such as squashes (Cucurbita spp.) were domesticated in the region. Our combined pollen, phytolith, charcoal, and sedimentary studies indicate that during the late glacial period (14,000-10,000 B.P.), lake beds were dry, the climate was cooler and drier, and open vegetational communities were more widespread than after the Pleistocene ended. Zea was a continuous part of the vegetation since at least the terminal Pleistocene. During the Holocene, lakes became important foci of human activity, and cultural interference with a species-diverse tropical forest is indicated. Maize and squash were grown at lake edges starting between 10,000 and 5,000 B.P., most likely sometime during the first half of that period. Significant episodes of climatic drying evidenced between 1,800 B.P. and 900 B.P. appear to be coeval with those documented in the Classic Maya region and elsewhere, showing widespread instability in the late Holocene climate.     

Predicting high-risk years for malaria in Colombia using parameters of El Niño Southern Oscillation

The interannual variation in malaria cases in Colombia between 1960 and 1992 shows a close association with a periodic climatic phenomenon known as El Niño Southern Oscilation (ENSO). Compared with other years, malaria cases increased by 17.3% during a Niño year and by 35.1% in the post Niño year. The annual total number of malaria cases is also strongly correlated ( r = 0.62, P < 0.001) with sea surface temperature (SST) anomalies in the eastern equatorial Pacific, a principal parameter of ENSO. The strong relation between malaria and ENSO in colombia can be used to predict high and low-risk years for malaria with sufficient time to mobilize resources to reduce the impact of epidemics. In view of the current El Niño conditions, we anticipate an increase in malaria cases in Colombia in 1998. Further studies to elucidate the mechanisms which underlie the association are required. As Colombia has a wide range of climatic conditions, regional studies relating climate and vector ecology to malaria incidence may further improve an ENSO-based early warning system. Predicting malaria risk associated with ENSO and related climate variables may also serve as a short-term analogue for predicting longer-term effects posed by global climate change.     

An Asian origin for a 10,000-year-old domesticated plant in the Americas

New genetic and archaeological approaches have substantially improved our understanding of the transition to agriculture, a major turning point in human history that began 10,000-5,000 years ago with the independent domestication of plants and animals in eight world regions. In the Americas, however, understanding the initial domestication of New World species has long been complicated by the early presence of an African enigma, the bottle gourd (Lagenaria siceraria). Indigenous to Africa, it reached East Asia by 9,000-8,000 before present (B.P.) and had a broad New World distribution by 8,000 B.P. Here we integrate genetic and archaeological approaches to address a set of long-standing core questions regarding the introduction of the bottle gourd into the Americas. Did it reach the New World directly from Africa or through Asia? Was it transported by humans or ocean currents? Was it wild or domesticated upon arrival? Fruit rind thickness values and accelerator mass spectrometer radiocarbon dating of archaeological specimens indicate that the bottle gourd was present in the Americas as a domesticated plant by 10,000 B.P., placing it among the earliest domesticates in the New World. Ancient DNA sequence analysis of archaeological bottle gourd specimens and comparison with modern Asian and African landraces identify Asia as the source of its introduction. We suggest that the bottle gourd and the dog, two "utility" species, were domesticated long before any food crops or livestock species, and that both were brought to the Americas by Paleoindian populations as they colonized the New World.     

Neither serum ferritin nor the number of red blood cell transfusions affect overall survival in refractory anemia with ringed sideroblasts

In a retrospective study of 126 adult patients with French-American-British-defined refractory anemia with ringed sideroblasts (RARS), staging by the International Prognostic Scoring System was highly predictive of survival outcome (P < 0.0001). In addition, red blood cell (RBC) transfusion requirement at diagnosis (P = 0.001), but not the number of RBC units transfused during the disease course (P = 0.17), was independently associated with inferior survival. There were no correlations between survival and serum ferritin level, measured either at diagnosis (median 567 ng/mL, range 16-3,475; P = 0.24) or during follow-up (median 1,108 ng/mL; range 238-43,500; P = 0.72). Similarly, there was no difference in survival when patients were stratified by serum ferritin levels of < or > or =1,000 ng/mL at diagnosis or peak serum ferritin levels of <1,000, 1,000-5,000, or >5,000 ng/mL during follow-up. The current study does not support the contention that transfusional hemosiderosis is an adverse prognostic factor in "good risk" myelodysplastic syndrome.     

Prognostic factors influencing survival in patients with B-cell small lymphocytic lymphoma

The term "B-cell small lymphocytic lymphoma" (B-SLL) is generally reserved for patients with lymph node masses that show the histology and immunophenotype of B-cell chronic lymphocytic leukemia (B-CLL) but who are not leukemic. The aim of our study was to define clinical factors that predict for survival in B-SLL. Thirty-nine patients with B-SLL and with less than 5,000 mature-appearing lymphocytes/microL in the peripheral blood were studied. The median follow-up of survivors was 6.6 years (range, 1.6-12.3 years). The estimated 5-year overall survival (OS) and failure-free survival (FFS) were 66% and 23%, respectively. In the univariate analysis, significant adverse predictors for OS were age > or =60 years, B symptoms, elevated serum LDH, low hemoglobin (<11 g/dL), and high International Prognostic Index (IPI) score (3-5). In multivariate analysis, the IPI score was the only significant predictor of OS. Anemia and B symptoms were additionally predictive of poor OS in patients with low IPI scores.     

Evidence for last interglacial chronology and environmental change from Southern Europe

Establishing phase relationships between earth-system components during periods of rapid global change is vital to understanding the underlying processes. It requires records of each component with independent and accurate chronologies. Until now, no continental record extending from the present to the penultimate glacial had such a chronology to our knowledge. Here, we present such a record from the annually laminated sediments of Lago Grande di Monticchio, southern Italy. Using this record we determine the duration (17.70 +/- 0.20 ka) and age of onset (127.20 +/- 1.60 ka B.P.) of the last interglacial, as reflected by terrestrial ecosystems. This record also reveals that the transitions at the beginning and end of the interglacial spanned only approximately 100 and 150 years, respectively. Comparison with records of other earth-system components reveals complex leads and lags. During the penultimate deglaciation phase relationships are similar to those during the most recent deglaciation, peaks in Antarctic warming and atmospheric methane both leading Northern Hemisphere terrestrial warming. It is notable, however, that there is no evidence at Monticchio of a Younger Dryas-like oscillation during the penultimate deglaciation. Warming into the first major interstadial event after the last interglacial is characterized by markedly different phase relationships to those of the deglaciations, warming at Monticchio coinciding with Antarctic warming and leading the atmospheric methane increase. Diachroneity is seen at the end of the interglacial; several global proxies indicate progressive cooling after approximately 115 ka B.P., whereas the main terrestrial response in the Mediterranean region is abrupt and occurs at 109.50 +/- 1.40 ka B.P.     

The protracted Holocene extinction of California's flightless sea duck (Chendytes lawi) and its implications for the Pleistocene overkill hypothesis

Bones of the flightless sea duck (Chendytes lawi) from 14 archaeological sites along the California coast indicate that humans hunted the species for at least 8,000 years before it was driven to extinction. Direct (14)C dates on Chendytes bones show that the duck was exploited on the southern California islands as early as approximately 11,150-10,280 calendar years B.P., and on the mainland by at least 8,500 calendar years B.P. The youngest direct date of 2,720-2,350 calendar years B.P., combined with the absence of Chendytes bones from hundreds of late Holocene sites, suggests that the species was extinct by approximately 2,400 years ago. Although the extinction of Chendytes clearly resulted from human overhunting, its demise raises questions about the Pleistocene overkill model, which suggests that megafauna were driven to extinction in a blitzkrieg fashion by Native Americans approximately 13,000 years ago. That the extermination of Chendytes was so protracted and archaeologically visible suggests that, if the terminal Pleistocene megafauna extinctions were primarily the result of human exploitation, there should also be a long and readily detectable archaeological record of their demise. The brief window now attributed to the Clovis culture ( approximately 13,300-12,900 B.P.) seems inconsistent with an overhunting event.     

Concordant mitochondrial and nuclear DNA phylogenies for populations of the teleost fish Fundulus heteroclitus.

Molecular phylogenies using mitochondrial DNA and nuclear alleles of the lactate dehydrogenase B locus were found to be concordant for populations of Fundulus heteroclitus ranging from Canada to Florida. Both mitochondrial DNA and lactate dehydrogenase alleles show a clear separation between the northern individuals (from Nova Scotia and Maine) and the southern ones (from Georgia and Florida), with a mixed population found in the geographic intermediate (New Jersey). An historical isolation, possibly as ancient as 0.5-1 million years old, may have played a role in shaping the situation observed today.     

Climatological determinants of woody cover in Africa

Determining the factors that influence the distribution of woody vegetation cover and resolving the sensitivity of woody vegetation cover to shifts in environmental forcing are critical steps necessary to predict continental-scale responses of dryland ecosystems to climate change. We use a 6-year satellite data record of fractional woody vegetation cover and an 11-year daily precipitation record to investigate the climatological controls on woody vegetation cover across the African continent. We find that-as opposed to a relationship with only mean annual rainfall-the upper limit of fractional woody vegetation cover is strongly influenced by both the quantity and intensity of rainfall events. Using a set of statistics derived from the seasonal distribution of rainfall, we show that areas with similar seasonal rainfall totals have higher fractional woody cover if the local rainfall climatology consists of frequent, less intense precipitation events. Based on these observations, we develop a generalized response surface between rainfall climatology and maximum woody vegetation cover across the African continent. The normalized local gradient of this response surface is used as an estimator of ecosystem vegetation sensitivity to climatological variation. A comparison between predicted climate sensitivity patterns and observed shifts in both rainfall and vegetation during 2009 reveals both the importance of rainfall climatology in governing how ecosystems respond to interannual fluctuations in climate and the utility of our framework as a means to forecast continental-scale patterns of vegetation shifts in response to future climate change.     

Early maize (Zea mays L.) cultivation in Mexico: dating sedimentary pollen records and its implications

A sedimentary pollen sequence from the coastal plain of Veracruz, Mexico, demonstrates maize cultivation by 5,000 years ago, refining understanding of the geography of early maize cultivation. Methodological issues related to bioturbation involved in dating that record combine with its similarity to a pollen sequence from the coastal plain of Tabasco, Mexico, to suggest that the inception of maize cultivation in that record occurred as much as 1,000-2,000 years more recently than the previously accepted 7,000 years ago. Our analysis thereby has substantive, theoretical, and methodological implications for understanding the complex process of maize domestication. Substantively, it demonstrates that the earliest securely dated evidence of maize comes from macrofossils excavated near Oaxaca and Tehuacán, Mexico, and not from the coastal plain along the southern Gulf of Mexico. Theoretically, that evidence best supports the hypothesis that people in the Southern Highlands domesticated this important crop plant. Methodologically, sedimentary pollen and other microfossil sequences can make valuable contributions to reconstructing the geography of early maize cultivation, but we must acknowledge the limits to precision that bioturbation in coastal lagoons imposes on the dating of such records.     

Defecation states in patients with or without soiling at 5 years or more after colectomy, mucosal proctectomy and ileal J pouch-anal anastomosis for ulcerative colitis

BACKGROUND/AIMS: There are no reports about the relationship between soiling and other defecation states in patients with ulcerative colitis (UC) after ileal J pouch-anal anastomosis (IPAA). To assess the defecation states in patients with or without soiling at 5 years or more after IPAA for UC, we studied clinical findings in such patients. METHODOLOGY: Subjects with UC who had undergone IPAA [a 5-cm short cuff, anal canal mucosa including anal transitional zone (AZT) stripped from the level of dentate line (DL)] with ileostomy closure at least 60 to 132 months (mean; 103.6 months) previously, and who had no pre- or postoperative complications were recruited. They were 43 patients (28 men and 15 women aged 15 to 59 years, average 39.2 years) divided into 2 groups; group A n=28; patients without soiling (18 men and 10 women aged 15 to 49 years, average 37.5 years) and group B n=15; patients with soiling (10 men and 5 women aged 24 to 59 years, average 42.1 years). Postoperative interviews concerning the defecation states (mean daily stool frequency, nocturnal stool frequency, ability to discriminate flatus from feces, feeling of stool remaining, consistence of stools, soiling, incontinence, and urgency) were conducted with patients after IPAA. RESULTS: No cases in group A showed soiling. All cases in group B had some soiling, 6 cases; rare soiling (at diarrhea), 4 cases; occasional soiling (1 time per 2 or 3 days), 4 cases; frequent soiling (patients must use pad due to daily soiling, 2 cases had incontinence). There was a significant difference between groups A and B (P < 0.001). All cases in group A showed less than 6 times per day and all cases of group B showed 7 or more times per day. There was a significant difference between groups A and B (P < 0.001). High nocturnal stool frequency was significantly more common in patients of group B than group A (P < 0.001). All cases in group A and 12 cases in group B could significantly discriminate flatus from feces (P < 0.05). Feeling of stool remaining was significantly more common in patients of group B than group A (P < 0.001). The stool consistency of group A was significantly harder than that of group B (P < 0.001). No cases in group A reported incontinence. Two cases in group B had incontinence. Urgency in group B was noted more than in group A. Regarding patient satisfaction (Peck's criteria), all cases in group B and no cases in group A reported "excellent". Ten cases in group B were "good". Three cases in group B were "fair". Two cases in group B showed failure. Patient satisfaction of group A was significantly higher than that of group B (P < 0.01). CONCLUSIONS: According to these interviews, no importance of preserving the AZT was recognized. The patients without soiling showed better defecation states than patients with soiling. The patients with soiling showed poor defecation status following     

On the influence of ENSO complexity on Pan-Pacific coastal wave extremes

Wind-generated waves are dominant drivers of coastal dynamics and vulnerability, which have considerable impacts on littoral ecosystems and socioeconomic activities. It is therefore paramount to improve coastal hazards predictions through the better understanding of connections between wave activity and climate variability. In the Pacific, the dominant climate mode is El Niño Southern Oscillation (ENSO), which has known a renaissance of scientific interest leading to great theoretical advances in the past decade. Yet studies on ENSO’s coastal impacts still rely on the oversimplified picture of the canonical dipole across the Pacific. Here, we consider the full ENSO variety to delineate its essential teleconnection pathways to tropical and extratropical storminess. These robust seasonally modulated relationships allow us to develop a mathematical model of coastal wave modulation essentially driven by ENSO’s complex temporal and spatial behavior. Accounting for this nonlinear climate control on Pan-Pacific wave activity leads to a much better characterization of waves’ seasonal to interannual variability (+25% in explained variance) and intensity of extremes (+60% for strong ENSO events), therefore paving the way for significantly more accurate forecasts than formerly possible with the previous baseline understanding of ENSO’s influence on coastal hazards.

As coastal breaking waves represent the ultimate dissipation of the energy generated by local and remote storms through large increases in surface wind over the ocean, their activity is modulated by the large-scale ocean–atmosphere coupled variability. This emphasizes the importance of better understanding the connections between coastal dynamics and modes of climate variability in order to improve their prediction at subseasonal timescales and beyond (1, 2). In particular, the Pacific basin is under the siege of El Niño Southern Oscillation (ENSO), the strongest interannual climate fluctuation, which has widespread effects on weather, climate, and societies (3). Recently, the littoral community has started to identify the role of ENSO as a major driver of coastal vulnerability across the Pacific (4, 5). The alternating coastal conditions, with shifts in wave activity and water-level anomalies between the northeastern and northwestern Pacific, were noted to mimic the well-known oscillations of ENSO phases. However, the Pacific wave climate and coastal variability associated with ENSO remains only understood at a basic reconnaissance level (6). As a matter of fact, even the most recent studies on the connection between wave climate and coastal extremes have only relied on a simplified view of ENSO (7, 8), omitting the existence of different regimes with distinct teleconnections and dynamics, recently coined “ENSO diversity and/or complexity” (9, 10).“ENSO diversity” originates from the concept that Sea Surface Temperature (SST) anomaly patterns exhibit wide variations. In particular, the repeated occurrence of SST patterns in the central Pacific (CP) in the 2000s suggested that ENSO events may be grouped into two flavors: the conventional El Niño, with SST anomalies concentrated in the eastern Pacific (EP El Niño), and the CP El Niño, with SST anomalies located around the dateline (11, 12). The “complexity” or sometimes “diversity and complexity” further refers to ENSO’s irregular temporal behavior characterized by large variations in amplitude and duration. In particular, recent progresses demonstrated that ENSO’s seasonal phase locking (i.e., its tendency to peak in boreal winter) (13) can produce a low-frequency instability known as the “Annual cycle-ENSO combination mode” and generate a deterministic variability at near-annual timescales, which significantly broadens the ENSO continuum (14). Such diversity and complexity translate to pronounced differences in remote ENSO climate impacts on the climate system through atmospheric and oceanic teleconnections (15, 16). In particular, one of ENSO’s most significant influences is its modulation of Tropical Cyclone (TC) activity, one of the most severe natural hazards (17). Because the large-scale air–sea environment mostly drives these storms, TC activity is substantially modified by ENSO through atmospheric and oceanic pathways (18). Similarly, ENSO also strongly affects extratropical storms and related coastal wave activity (19, 20).A variety of oceanic and atmospheric wave reanalysis products and TC databases were examined to capture comprehensively the regional and large-scale climate variability in the Pacific associated with ENSO diversity and complexity and how it affects coastal waves’ variability. More specifically and unlike any previous studies, the focus is not solely directed toward the direct influence on extratropical wave patterns of El Niño at its winter peak but also on its delayed and early effects on summer TC storminess considered as an integral wave regime potentially affecting coastlines far from the storms’ generation (21). In particular, since ENSO’s influences on tropical and extratropical storm activity are subject to a strong seasonal synchronization, the combined ENSO–Annual cycle influence on teleconnections patterns and coastal wave variability is considered. Insights from these unraveled seasonally modulated ENSO teleconnections allow us to develop a simple mathematical model that points toward a strong predictability of the Pacific coastal wave variability over a range of timescales much broader than just the interannual band and therefore opens up the door for predictions of coastal hazards significantly more accurate than current state-of-the-art seasonal forecasts.     

Association of early annual peak influenza activity with El Niño southern oscillation in Japan

Background Seasonality characterizing influenza epidemics suggests susceptibility to climate variation. El Niño southern oscillation (ENSO), which involves two extreme events, El Niño and La Niña, is well‐known for its large effects on inter‐annual climate variability. The influence of ENSO on several diseases has been described. Objectives In this study, we attempt to analyze the possible influence of ENSO on the timing of the annual influenza activity peak using influenza‐like illness report data in Japan during 1983–2007. Materials Influenza surveillance data for 25 influenza epidemics, available under the National Epidemiological Surveillance of the Infectious Diseases, was used in this study. ENSO data were obtained from the Japan Meteorological Agency. Results Influenza‐like illness peak week varied largely during the study period, ranging between 4th and 11th weeks (middle of winter to early spring). The average of peak week during ENSO cycles (n = 11, average = 4·5 ± 0·9) was significantly earlier than in non‐ENSO years (n = 14, average = 7·6 ± 2·9; P = 0·01), but there was no significant difference in the peak timing between hot (El Niño) and cold (La Niña) phases. Earlier peaks of influenza activity were observed in 16, out of 25, epidemics. These coincided with 10 (90·9%) out of 11 ENSO and 6 (85·7%) out of seven large‐scale epidemics. Conclusion Influenza activity peak occurred earlier in years associated with ENSO and/or large scale epidemics.     

Strong influence of El Ni?o Southern Oscillation on flood risk around the world

El Niño Southern Oscillation (ENSO) is the most dominant interannual signal of climate variability and has a strong influence on climate over large parts of the world. In turn, it strongly influences many natural hazards (such as hurricanes and droughts) and their resulting socioeconomic impacts, including economic damage and loss of life. However, although ENSO is known to influence hydrology in many regions of the world, little is known about its influence on the socioeconomic impacts of floods (i.e., flood risk). To address this, we developed a modeling framework to assess ENSO’s influence on flood risk at the global scale, expressed in terms of affected population and gross domestic product and economic damages. We show that ENSO exerts strong and widespread influences on both flood hazard and risk. Reliable anomalies of flood risk exist during El Niño or La Niña years, or both, in basins spanning almost half (44%) of Earth’s land surface. Our results show that climate variability, especially from ENSO, should be incorporated into disaster-risk analyses and policies. Because ENSO has some predictive skill with lead times of several seasons, the findings suggest the possibility to develop probabilistic flood-risk projections, which could be used for improved disaster planning. The findings are also relevant in the context of climate change. If the frequency and/or magnitude of ENSO events were to change in the future, this finding could imply changes in flood-risk variations across almost half of the world’s terrestrial regions.El Niño Southern Oscillation (ENSO) is the most dominant interannual signal of climate variability on Earth (1) and influences climate over large parts of the Earth’s surface. In turn, ENSO is known to strongly influence many physical processes and societal risks, including droughts, food production, hurricane damage, and tropical tree cover (2–4). For decision makers it is essential to have information on the possible impacts of this climate variability on society. Such information can be particularly useful when the climate variability can be anticipated in advance, thus allowing for early warning and disaster planning (5). For example, projections carried out in September 2013 already suggested a 75% likelihood that El Niño conditions would develop in late 2014 (6). According to the ENSO forecast of the International Research Institute for Climate and Society and the Climate Prediction Center/NCEP/NWS, dated 9 October 2014, observed ENSO conditions did indeed move to those of a borderline El Niño during September and October 2014, with indications of weak El Niño conditions during the northern hemisphere winter 2014–2015 (iri.columbia.edu/our-expertise/climate/forecasts/enso/current/).However, to date little is known on ENSO’s influence on flood risk, whereby risk is defined as a function of hazard, exposure, and vulnerability (7) and is expressed in terms of socioeconomic indicators such as economic damage or affected people. Although global-scale flood-risk assessments have recently become a hot topic in both the scientific and policy communities, assessments to date have focused on current risks (7–11) or future risks under long-term mean climate change (12, 13). Meanwhile, other recent research suggests that ENSO-related variations of precipitation are likely to intensify in the future (14, 15) and that extreme El Niño events may increase in frequency (16). Hence, an understanding of ENSO’s influence on flood risk is vital in understanding both the possible impacts of upcoming ENSO events as well as planning for the potential socioeconomic impacts of changes in future ENSO frequency.In this paper, we show for the first time to our knowledge that ENSO has a very strong influence on flood risk in large parts of the world. These findings build on previous studies, especially in Australia and the United States, which show that ENSO and other forms of climate variability are strongly related to flood hazard in some regions (17–25). To do this, we developed a modeling framework to specifically assess ENSO’s influence on global flood risk. The modeling framework involves using a cascade of hydrological, hydraulic, and impact models (10, 11). Using this model cascade, we assessed flood impacts in terms of three indicators: (i) exposed population, (ii) exposed gross domestic product (GDP), and (iii) urban damage (Materials and Methods). A novel aspect of the framework is that we are able to calculate flood risk conditioned on the climatology of all years, El Niño years only, and La Niña years only. This allows us, for the first time to our knowledge, to simulate the impacts of ENSO on flood risk. The hydrological and impact models have previously been validated for the period 1958–2000 (11). Here, we carried out further validation to assess the specific ability of the model cascade to simulate year-to-year fluctuations in peak river flows and flood impacts and anomalies in peak flows and impacts during El Niño and La Niña years (SI Discussion, Validation of Hydrological and Hydraulic Models).     

Contingent Pacific-Atlantic Ocean influence on multicentury wildfire synchrony over western North America

Widespread synchronous wildfires driven by climatic variation, such as those that swept western North America during 1996, 2000, and 2002, can result in major environmental and societal impacts. Understanding relationships between continental-scale patterns of drought and modes of sea surface temperatures (SSTs) such as El Ni?o-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and Atlantic Multidecadal Oscillation (AMO) may explain how interannual to multidecadal variability in SSTs drives fire at continental scales. We used local wildfire chronologies reconstructed from fire scars on tree rings across western North America and independent reconstructions of SST developed from tree-ring widths at other sites to examine the relationships of multicentury patterns of climate and fire synchrony. From 33,039 annually resolved fire-scar dates at 238 sites (the largest paleofire record yet assembled), we examined forest fires at regional and subcontinental scales. Since 1550 CE, drought and forest fires covaried across the West, but in a manner contingent on SST modes. During certain phases of ENSO and PDO, fire was synchronous within broad subregions and sometimes asynchronous among those regions. In contrast, fires were most commonly synchronous across the West during warm phases of the AMO. ENSO and PDO were the main drivers of high-frequency variation in fire (interannual to decadal), whereas the AMO conditionally changed the strength and spatial influence of ENSO and PDO on wildfire occurrence at multidecadal scales. A current warming trend in AMO suggests that we may expect an increase in widespread, synchronous fires across the western U.S. in coming decades.     

From the Cover: Tales of volcanoes and El-Ni?o southern oscillations with the oxygen isotope anomaly of sulfate aerosol

The ability of sulfate aerosols to reflect solar radiation and simultaneously act as cloud condensation nuclei renders them central players in the global climate system. The oxidation of S(IV) compounds and their transport as stable S(VI) in the Earth’s system are intricately linked to planetary scale processes, and precise characterization of the overall process requires a detailed understanding of the linkage between climate dynamics and the chemistry leading to the product sulfate. This paper reports a high-resolution, 22-y (1980–2002) record of the oxygen-triple isotopic composition of sulfate (SO₄) aerosols retrieved from a snow pit at the South Pole. Observed variation in the O-isotopic anomaly of SO₄ aerosol is linked to the ozone variation in the tropical upper troposphere/lower stratosphere via the Ozone El-Niño Southern Oscillations (ENSO) Index (OEI). Higher ∆¹⁷O values (3.3‰, 4.5‰, and 4.2‰) were observed during the three largest ENSO events of the past 2 decades. Volcanic events inject significant quantities of SO₄ aerosol into the stratosphere, which are known to affect ENSO strength by modulating stratospheric ozone levels (OEI = 6 and ∆¹⁷O = 3.3‰, OEI = 11 and ∆¹⁷O = 4.5‰) and normal oxidative pathways. Our high-resolution data indicated that ∆¹⁷O of sulfate aerosols can record extreme phases of naturally occurring climate cycles, such as ENSOs, which couple variations in the ozone levels in the atmosphere and the hydrosphere via temperature driven changes in relative humidity levels. A longer term, higher resolution oxygen-triple isotope analysis of sulfate aerosols from ice cores, encompassing more ENSO periods, is required to reconstruct paleo-ENSO events and paleotropical ozone variations.     

1,500 year quantitative reconstruction of winter precipitation in the Pacific Northwest

Multiple paleoclimate proxies are required for robust assessment of past hydroclimatic conditions. Currently, estimates of drought variability over the past several thousand years are based largely on tree-ring records. We produced a 1,500-y record of winter precipitation in the Pacific Northwest using a physical model-based analysis of lake sediment oxygen isotope data. Our results indicate that during the Medieval Climate Anomaly (MCA) (900–1300 AD) the Pacific Northwest experienced exceptional wetness in winter and that during the Little Ice Age (LIA) (1450–1850 AD) conditions were drier, contrasting with hydroclimatic anomalies in the desert Southwest and consistent with climate dynamics related to the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). These findings are somewhat discordant with drought records from tree rings, suggesting that differences in seasonal sensitivity between the two proxies allow a more compete understanding of the climate system and likely explain disparities in inferred climate trends over centennial timescales.     

Resultados a corto y medio plazo de la técnica de Florida Sleeve en la dilatación de raíz aórtica

Introduction:

Aortic root dilatation is a frequent disease affecting mostly young patients that often requires surgical repair. Surgical techniques in young patients include aortic valve-sparing procedures to avoid prosthetic valve implant.

Objective:

The aim of this paper is to describe the results obtained in three patients with aortic root dilatation using the Florida Sleeve technique.

Methods:

From November 2015 to January 2017, three patients with severe aortic regurgitation due to aortic anuloectasic were intervened applying the Florida Sleeve technique.

Results:

Excellent postoperative results were obtained in the three cases including freedom of aortic regurgitation and any cause re-operation during three years of follow-up.

Conclusion:

The Florida Sleeve technique is a safe, reproducible technique with a learning curve and lower surgical times than traditional techniques. The medium-term clinical outcomes in terms of morbidity and mortality are good.Key words: Florida Sleeve, Aortic root dilatation, Aortic regurgitation     

The ten-year malpractice experience of a large urban EMS system

Malpractice is a recognized and growing problem for physicians and hospitals, but it is difficult to ascertain the risk of malpractice in the prehospital arena. Dade County, Florida (greater Miami), with a population of 1.7 million, currently is served by 339 certified paramedics. During the decade of 1972 to 1982, Dade County Fire Rescue handled 265,060 incidents; 16 claims were filed with the Risk Management Division of Dade County. The claims were produced by 11 incidents, which yields a rate of one per 24,096 incidents. The two greatest problems identified were inadequate record keeping and "gray zone" patients who do not fit any particular protocol.     

Oxygen isotopes in tree rings are a good proxy for Amazon precipitation and El Ni?o-Southern Oscillation variability

We present a unique proxy for the reconstruction of variation in precipitation over the Amazon: oxygen isotope ratios in annual rings in tropical cedar (Cedrela odorata). A century-long record from northern Bolivia shows that tree rings preserve the signal of oxygen isotopes in precipitation during the wet season, with weaker influences of temperature and vapor pressure. Tree ring δ¹⁸O correlates strongly with δ¹⁸O in precipitation from distant stations in the center and west of the basin, and with Andean ice core δ¹⁸O showing that the signal is coherent over large areas. The signal correlates most strongly with basin-wide precipitation and Amazon river discharge. We attribute the strength of this (negative) correlation mainly to the cumulative rainout processes of oxygen isotopes (Rayleigh distillation) in air parcels during westward transport across the basin. We further find a clear signature of the El Niño-Southern Oscillation (ENSO) in the record, with strong ENSO influences over recent decades, but weaker influence from 1925 to 1975 indicating decadal scale variation in the controls on the hydrological cycle. The record exhibits a significant increase in δ¹⁸O over the 20th century consistent with increases in Andean δ¹⁸O ice core and lake records, which we tentatively attribute to increased water vapor transport into the basin. Taking these data together, our record reveals a fresh path to diagnose and improve our understanding of variation and trends of the hydrological cycle of the world’s largest river catchment.