Atlantic hurricane season length is important for emergency management preparation, motivating the need to understand its variability and change. We investigated the influence of ocean variability on ...Atlantic hurricane season length in observations and a future climate simulated by the Energy Exascale Earth System Model (E3SM). We found that multiple factors influence hurricane season length, through their influence on season start and end. Warm western subtropical Atlantic sea‐surface temperature anomalies (SSTAs) during boreal spring (before the official hurricane season start) drive early starts to the hurricane season, and vice versa for cool SSTAs. Meanwhile, La Niña in autumn (before the official hurricane season end) drives late ends to the hurricane season, and vice versa for El Niño. E3SM projects a 27‐day increase in future Atlantic hurricane season length given La Niña and warm northern tropical Atlantic SSTAs. This research documents sources of predictability for Atlantic hurricane season length.
Plain Language Summary
Atlantic hurricane season length is important for emergency management preparation, motivating the need to understand its variability and change. We investigated the influence of ocean variability on Atlantic hurricane season length in historical observations and a future climate simulated by a global climate model. We found that multiple factors influence Atlantic hurricane season length, through their influence on season start and end. Warm sea‐surface temperature anomalies (SSTAs) in the western subtropical Atlantic during boreal spring (before the official hurricane season start) drive early starts to the hurricane season, and vice versa for cool SSTAs. Meanwhile, La Niña events in autumn (before the official hurricane season ends) drive late ends to the hurricane season, and vice versa for El Niño. The global model projects a 27–41‐day increase in future Atlantic hurricane season length. This research documents sources of predictability for Atlantic hurricane season length.
Key Points
Multiple oceanic factors influence Atlantic hurricane season length, by influencing the first and last Tropical Storm of the season
A warm western subtropical Atlantic ocean in boreal spring drives early hurricane season starts; La Niña in autumn drives late season ends
Future Atlantic hurricane season length increases by 27 days in Energy Exascale Earth System Model simulations given La Niña and a positive Atlantic Meridional Mode
The Madden Julian Oscillation (MJO) is the main source of intraseasonal variability in the tropics. MJO modulates rainfall in remote areas in the Southern Hemisphere by exciting tropical and ...extratropical wave trains. We use newly released reanalysis data to analyze how the Quasi‐Biennial Oscillation (QBO) can influence the MJO's effects over the Southern Hemisphere, focusing on precipitation anomalies over South America. The anomalies in the intensity of the South Atlantic Convergence Zone (SACZ) and precipitation over Southeastern South America during MJO phases 1 and 4 are intensified during the easterly QBO. The extratropical wave train excited by the anomalous convection over the maritime continent during MJO phase 4 is affected by the QBO, with a stronger, better‐defined pattern during westerly QBO. The conclusions are supported by a perturbation experiment of a case study, conducted using a high‐top atmospheric global climate model where the QBO and MJO are controlled.
Plain Language Summary
Subseasonal to seasonal prediction remains challenging in the current forecast models. Previous studies have shown that the Quasi‐Biennial Oscillation (QBO) can influence the intensity and development of the Madden Julian Oscillation (MJO). Here, the consequences of this modulation on the remote effects of the MJO in the Southern Hemisphere are analyzed using reanalysis and perturbation experiments in an atmospheric global climate model. The rainfall anomalies related to the MJO in South America are more intense and widespread during easterly QBO over the South Atlantic Convergence Zone and southern Brazil than during westerly QBO. Thus, the inclusion of the state of the QBO in the estimate of the expected rainfall associated with the MJO is crucial to improve forecasts in the region.
Key Points
The Quasi‐Biennial Oscillation (QBO) modulates the impacts of the Madden Julian Oscillation (MJO) in the Southern Hemisphere
MJO‐related rainfall anomalies in the South Atlantic Convergence Zone are intensified during easterly QBOE
The extratropical wave train forced by the anomalous convection in MJO phase 4 is intensified under QBOW
The influence of each phase of the Indian Ocean dipole (IOD) on the large-scale circulation in South America is investigated using rainfall observations, fully coupled, large-ensemble, historical ...simulations (LENS), and forced experiments using the coupled model’s atmospheric component. IOD events often occur when El Niño–Southern Oscillation (ENSO), the largest source of interannual variability of precipitation in South America, is active. To distinguish from effects of ENSO, only cases during neutral ENSO conditions are analyzed in LENS and observations. During the positive IOD polarity, a perturbation in the local Walker circulation leads to increased convection over equatorial South America, resulting in wet anomalies in the Amazon basin. This signal is the opposite of what is expected during El Niño events. Tropical convection anomalies in the Indian Ocean also force an extratropical Rossby wave train that reaches subtropical South America. During positive IOD, the moisture flux from the Amazon to central and southeastern Brazil weakens, resulting in a drying of the area associated with the South Atlantic convergence zone. Meanwhile, the South Atlantic subtropical high strengthens, contributing to a drying in southeastern Brazil. During negative IOD, the induced wave train from the Indian Ocean leads to increased moisture transport to the La Plata basin, leading to wet anomalies in the region.
North Atlantic tropical cyclones (TCs) have considerable interannual variability, with La Niña and the positive phase of the Atlantic Meridional Mode (AMM) tending to drive active hurricane seasons, ...and El Niño and the negative AMM often driving inactive seasons. Here, we analyze how active and inactive Atlantic hurricane seasons may change in the future using the high resolution Energy Exascale Earth System Model (E3SM). We performed atmosphere‐only simulations forced by sea‐surface temperature patterns characteristic of La Niña and the positive AMM jointly, and El Niño and the negative AMM jointly, in historical and future climates. Projected Atlantic TCs become more frequent in the future by approximately 34% during El Niño and negative AMM and by 66% during La Niña and positive AMM, with a significant increase in the portion of intense TCs. Warmer SSTs increase TC potential intensity, with reduced wind shear and increased mid‐tropospheric humidity further supporting TC activity.
Plain Language Summary
Tropical cyclones (TCs) are among the most destructive natural disasters worldwide. Here, we assess how the frequency and intensity of TCs in the North Atlantic are projected to change in a warming climate. We performed high resolution global climate model simulations in which sea surface temperature patterns associated with active and inactive Atlantic hurricane seasons were applied in both historical and future climate scenarios. We found that Atlantic TCs are projected to become more frequent and intense in the future in both active and inactive seasons, with a greater intensification during active TC seasons. These results shed light on the importance of considering changes not only in the mean, but also in year‐to‐year variability, when analyzing future projections of TC activity.
Key Points
We project future change in active and inactive Atlantic hurricane seasons driven by El Niño—Southern Oscillation and the Atlantic Meridional Mode
Future Atlantic tropical cyclone (TC) frequency increases during active and inactive seasons, with greater increases in the active season
Increased potential intensity and relative humidity and decreased shear support stronger and more frequent TCs in the future
Abstract
North Atlantic tropical cyclones (TCs) have considerable interannual variability, with La Niña and the positive phase of the Atlantic Meridional Mode (AMM) tending to drive active hurricane ...seasons, and El Niño and the negative AMM often driving inactive seasons. Here, we analyze how active and inactive Atlantic hurricane seasons may change in the future using the high resolution Energy Exascale Earth System Model (E3SM). We performed atmosphere‐only simulations forced by sea‐surface temperature patterns characteristic of La Niña and the positive AMM jointly, and El Niño and the negative AMM jointly, in historical and future climates. Projected Atlantic TCs become more frequent in the future by approximately 34% during El Niño and negative AMM and by 66% during La Niña and positive AMM, with a significant increase in the portion of intense TCs. Warmer SSTs increase TC potential intensity, with reduced wind shear and increased mid‐tropospheric humidity further supporting TC activity.
Understanding the causes of death in dogs enhances the diagnostic capabilities of veterinarians, as well as reduces animal mortality. Studies on this topic assist in the control and prophylaxis of ...epidemics and in structuring public health programmes. In total, 1 355 necropsy reports of dogs filed at the Veterinary Pathology Laboratory of the Federal University of Bahia, Northeast, Brazil (2005–2017) were analysed. The epidemiological information and anatomopathological diagnoses were obtained. The diagnosed diseases were classified into 10 categories. The frequency of the zoonoses, the overall age of the death (AD) of the dogs, and the AD of the dogs for each disease category were determined. Infectious and parasitic diseases were the most frequent primary causes of death in puppies (44.62%) and adult dogs (26.52%). In elderly dogs, most deaths occurred due to neoplasms (42.37%). Distemper (10.46%) was the most prevalent condition. A high frequency of zoonoses (6.12%) and a high death rate caused by diseases that could have been prevented (15.06%), such as distemper, parvovirus and canine visceral leishmaniasis, were reported. The AD in the population studied was eight years. The results confirmed the hypothesis of a high death rate in dogs in the state of Bahia, Northeast, Brazil, because of preventable infectious diseases.
INTRODUCTION: The development of new therapeutics is often characterised by promising animal research that fails to translate into clinical efficacy; this holds for the development of gene therapy in ...glioma. We set out to test the hypothesis that this is because of limitations in the internal and external validity of studies reporting the use of gene therapy in rodent models of glioma. METHOD: We systematically identified studies testing gene therapy in rodent glioma models by searching three online databases. The number of animals treated and median survival were extracted and studies graded using a 9-point quality checklist. We calculated median survival ratios and used random effects meta-analysis to provide estimates of efficacy. We explored the effects of study design and quality and searched for evidence of publication bias. RESULTS: We found 194 publications using gene therapy in experimental glioma, describing 427 experiments involving 6366 animals. Overall, genetherapy improved median survival by 1.60 fold (95%CI 1.53-1.67). Study quality was low and the type of gene therapy did not account for observed differences in outcome. Study design characteristics accounted for a significant proportion of between-study heterogeneity and we observedsimilar findings in a subset of data limited to the most common genetherapy. CONCLUSION: As the dysregulation of key molecular pathways is characteristic of gliomas, gene therapy remains a promising treatment forglioma. Nevertheless, we have identified areas for improvement in conduct and reporting of such studies. Further work should focus on genes of interest in paradigms that recapitulate human disease. This may improve the translation of such therapies into the clinic.
We use laser-assisted microdissection to characterize the female floral transcriptome of the early diverging angiosperm Amborella trichopodaand present a novel protocol to compare transcriptomic data ...between widely diverged plant species.
Abstract
We have devised a procedure for the inter-species comparison of transcriptomic data and used this procedure to reconstruct the expression dynamics of major genetic modules that were present at least 149 million years ago in the most recent common ancestor of living angiosperms. We began by using laser-assisted microdissection to generate novel transcriptomic data from female flower tissues of Amborella trichopoda, the likely sister to all other living angiosperms. We then employed a gene-expression clustering method, followed by a custom procedure to compare genetic modules on the basis of gene orthology between Amborella and the molecular-genetic model angiosperm Arabidopsis thaliana. Using this protocol, we succeeded in identifying nine major genetic modules that appear to have conserved their expression dynamics from an early stage in angiosperm evolution. The genes of these modules, representing over 5000 orthogroups, include around one third of those known to control female reproductive development in Arabidopsis. Our study constitutes a proof of concept for the comparison of transcriptomic data between widely diverged plant species and represents a first step in the large-scale analysis of gene expression dynamics in a macro-evolutionary context.
Landscape fires, often referred to as biomass burning
(BB), emit substantial amounts of (greenhouse) gases and aerosols into the
atmosphere each year. Frequently burning savannas, mostly in Africa,
...Australia, and South America are responsible for over 60 % of total BB
carbon emissions. Compared to many other sources of emissions, fires have a
strong seasonality. Previous research has identified the mitigation
potential of prescribed fires in savanna ecosystems; by burning cured fuels
early in the dry season when landscape conditions still provide moist
buffers against fire spread, fires are in general smaller, patchier, and less
intense. While it is widely accepted that burned area (BA) and the total
carbon consumed are lower when fires are ignited early in the dry season,
little is known about the intraseasonal variability of emission factors (EFs).
This is important because potentially, higher EFs in the early dry season
(EDS) could offset some of the carbon benefits of EDS burning. Also, a
better understanding of EF intraseasonal variability may improve large-scale
BB assessments, which to date rely on temporally static EFs. We used a
sampling system mounted on an unmanned aerial vehicle (UAV) to sample BB
smoke in the Estação Ecológica Serra Geral do Tocantins in the
Brazilian states of Tocantins and Bahia. The protected area contains all
major Cerrado vegetation types found in Brazil, and EDS burning has been
implemented since 2014. Over 800 smoke samples were
collected and analysed during the EDS of 2018 and late dry season (LDS) of
2017 and 2018. The samples were analysed using cavity ring-down spectroscopy,
and the carbon balance method was used to estimate CO2, CO, CH4,
and N2O EFs. Observed EF averages and standard deviations were 1651
(±50) g kg−1 for CO2, 57.9 (±28.2) g kg−1 for
CO, 0.97 (±0.82) g kg−1 for CH4, and 0.096 (±0.174) g kg−1 for N2O. Averaged over all measured fire prone Cerrado types, the modified
combustion efficiency (MCE) was slightly higher in the LDS (0.961 versus 0.956),
and the CO and CH4 were 10 % and 2.3 % lower in the LDS compared to the
EDS. However, these differences were not statistically significant using a
two-tailed t test with unequal variance at a 90 %
significance level. The seasonal effect was larger in more wood-dominated
vegetation types. N2O EFs showed a more complex seasonal dependency,
with opposite intraseasonal trends for savannas that were dominated by grasses
versus those with abundant shrubs. We found that the N2O EF for the
open Cerrado was less than half the EF suggested by literature compilations for savannas.
This may indicate a substantial overestimation of the contribution of fires
in the N2O budget. Overall, our data imply that in this region,
seasonal variability in greenhouse gas emission factors may offset only a
small fraction of the carbon mitigation gains in fire abatement programmes.
Recently, the tiger-cat species complex was split into Leopardus tigrinus and Leopardus guttulus, along with other proposed schemes. We performed a detailed analysis integrating ecological modeling, ...biogeography, and phenotype of the four originally recognized subspecies-tigrinus, oncilla, pardinoides, guttulus-and presented a new multidimensional niche depiction of the species. Species distribution models used > 1400 records from museums and photographs, all checked for species accuracy. Morphological data were obtained from institutional/personal archives. Spotting patterns were established by integrating museum and photographic/camera-trap records. Principal component analysis showed three clearly distinct groups, with the Central American specimens (oncilla) clustering entirely within those of the Andes, namely the pardinoides group of the cloud forests of the southern Central-American and Andean mountain chains (clouded tiger-cat); the tigrinus group of the savannas of the Guiana Shield and central/northeastern Brazil (savanna tiger-cat); and the guttulus group in the lowland forests of the Atlantic Forest domain (Atlantic Forest tiger-cat). This scheme is supported by recent genetic analyses. All species displayed different spotting patterns, with some significant differences in body measurements/proportions. The new distribution presented alarming reductions from the historic range of - 50.4% to - 68.2%. This multidimensional approach revealed a new species of the elusive and threatened tiger-cat complex.
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