Intraseasonal variability of air-sea fluxes over the Bay of Bengal during the southwest monsoon

In the Bay of Bengal (BoB), surface heat fluxes play a key role in monsoon dynamics and prediction. The accurate representation of large-scale surface fluxes is dependent on the quality of gridded reanalysis products. Meteorological and surface flux variables from five reanalysis products are compared and evaluated against in situ data from the RAMA moored array in the BoB. The reanalysis products: ERA-Interim (ERA-I), TropFlux, MERRA-2, JRA-55 and CFSR are assessed for their characterisation of air-sea fluxes during the southwest monsoon season (JJAS). ERA-I captured radiative fluxes best while TropFlux captured turbulent and net heat fluxes (Qnet) best, and both products outperformed JRA-55, MERRA-2 and CFSR, showing highest correlations and smallest biases when compared to the in situ data. In all five products, the largest errors were in shortwave radiation (QSW) and latent heat flux (QLH), with non-negligible biases up to ∼75 W m−2. The QSW and QLH are the largest drivers of the observed Qnet variability, thus highlighting the importance of the results from the buoy comparison. There are also spatially coherent differences in the mean basin-wide fields of surface flux variables from the reanalysis products, indicating that the biases at the buoy position are not localized. Biases of this magnitude have severe implications on reanalysis products ability to capture the variability of monsoon processes. Hence, the representation of intraseasonal variability was investigated through the boreal summer intraseasonal oscillation and we found that TropFlux and ERA-I perform best at capturing intraseasonal climate variability during the southwest monsoon season

A Comparison of Swimming Economy Between Two Full-Sleeve Wetsuits

A wetsuit is an important piece of equipment that a triathlete uses during their swim-bike-run race. Wetsuits differ based on style (e.g., full-sleeve or sleeveless), manufacturer and price. PURPOSE: The purpose of this study was to compare swimming economy in two full-sleeve wetsuits in a group of recreational swimmers and triathletes. METHODS: Nine men (34.3 ± 13.3 years old) and six women (37.8 ± 16.0 years old) completed a progressive swim test to exhaustion in a swim flume without a wetsuit to determine their peak rate of oxygen consumption (VO2peak). This was followed by three 5-min swimming bouts at a constant, submaximal speed. The three trials were randomized and consisted of an entry-level full-sleeve wetsuit (blueseventy Sprint), a high-end full-sleeve wetsuit (blueseventy Helix) and no wetsuit. Rates of O2 consumption and CO2 production were measured using a metabolic cart and heart rate was determined with a chest strap. Data from the last 2 min of each submaximal swimming trial were analyzed. RESULTS: Peak rate of O2 consumption was 40.6 ± 8.0 ml kg-1 min-1 and corresponded to a respiratory exchange ratio, heart rate and rating of perceived exertion (RPE; Borg scale) of 0.97 ± 0.07, 165 ± 12 bpm, and 16.2 ± 1.7, respectively. The pace for the submaximal swimming trials was 1.02 ± 0.14 m/s, which corresponded to 79.7% ± 6.7% of their VO2peak. The subjects expended 9.8 ± 2.7 and 9.9 ± 2.9 kcal/min while swimming in the high-end and entry-level wetsuit, respectively. Both wetsuits reduced energy expenditure compared to swimming without a wetsuit (11.8 ± 3.5 kcal/min; p \u3c 0.001). Heart rate was significantly higher (p \u3c 0.001) with no wetsuit (146 ± 12 bpm), but did not differ between wetsuits (high-end 137 ± 13 bpm; entry-level 137 ±15 bpm). Arm cadence did not differ between trials (p = 0.571). Lastly, RPE was 12.1 ± 1.6 with no wetsuit compared to 10.9 ± 1.4 (p = 0.018) and 11.1 ± 1.5 (p = 0.051) for the high-end and entry-level wetsuits, respectively. CONCLUSION: The were no differences in any measured variable between wetsuits, although swimming with either wetsuit was more economical compared to swimming without a wetsuit. Data from this study suggest that a wetsuit should be worn when allowed but that the specific model of wetsuit may be less important. Future studies should compare two homogenous groups of swimmers or triathletes (e.g., elite vs. beginner) or see how wearing a wetsuit affects performance during the cycling segment of a triathlon

The Dynamics of the Southwest Monsoon Current in 2016 from High-Resolution In Situ Observations and Models

The strong stratification of the Bay of Bengal (BoB) causes rapid variations in sea surface temperature (SST) that influence the development of monsoon rainfall systems. This stratification is driven by the salinity difference between the fresh surface waters of the northern bay and the supply of warm, salty water by the Southwest Monsoon Current (SMC). Despite the influence of the SMC on monsoon dynamics, observations of this current during the monsoon are sparse. Using data from high-resolution in situ measurements along an east–west section at 8°N in the southern BoB, we calculate that the northward transport during July 2016 was between 16.7 and 24.5 Sv (1 Sv ≡ 106 m3 s−1), although up to ⅔ of this transport is associated with persistent recirculating eddies, including the Sri Lanka Dome. Comparison with climatology suggests the SMC in early July was close to the average annual maximum strength. The NEMO 1/12° ocean model with data assimilation is found to faithfully represent the variability of the SMC and associated water masses. We show how the variability in SMC strength and position is driven by the complex interplay between local forcing (wind stress curl over the Sri Lanka Dome) and remote forcing (Kelvin and Rossby wave propagation). Thus, various modes of climatic variability will influence SMC strength and location on time scales from weeks to years. Idealized one-dimensional ocean model experiments show that subsurface water masses advected by the SMC significantly alter the evolution of SST and salinity, potentially impacting Indian monsoon rainfall

Effect of co-infection with a small intestine-restricted helminth pathogen on oral prion disease pathogenesis in mice

The early replication of some orally-acquired prion strains upon stromal-derived follicular dendritic cells (FDC) within the small intestinal Peyer’s patches is essential to establish host infection, and for the disease to efficiently spread to the brain. Factors that influence the early accumulation of prions in Peyer’s patches can directly influence disease pathogenesis. The host’s immune response to a gastrointestinal helminth infection can alter susceptibility to co-infection with certain pathogenic bacteria and viruses. Here we used the natural mouse small intestine-restricted helminth pathogen Heligmosomoides polygyrus to test the hypothesis that pathology specifically within the small intestine caused by a helminth co-infection would influence oral prion disease pathogenesis. When mice were co-infected with prions on d 8 after H. polygyrus infection the early accumulation of prions within Peyer’s patches was reduced and survival times significantly extended. Natural prion susceptible hosts such as sheep, deer and cattle are regularly exposed to gastrointestinal helminth parasites. Our data suggest that co-infections with small intestine-restricted helminth pathogens may be important factors that influence oral prion disease pathogenesis

Development of in vitro systems to study IFN signalling in gilthead seabream (Sparus aurata)

Type I interferon (IFN I) triggers specific signalling pathways leading to the activation of the innate immune defence of vertebrates against viral infections. In contrats, type II IFN (IFN II) is generally accepted to be part of the adaptive response. Among IFN I-stimulated genes, those coding the Mx proteins play a main role due to the direct antiviral activity of these proteins. The study of Mx genes in gilthead seabream, one of the most important species in the Mediterranean aquaculture, is especially interesting, as this species displays a high natural resistance to viral diseases, and behaves as asymptomatic carrier and/or reservoir of several viruses, such as viral nervous necrosis virus (VNNV), infectious pancreatic necrosis virus (IPNV), and viral haemorrhagic septicaemia virus (VHSV), which are pathogenic to other fish species. Three Mx genes (Mx1, Mx2, and Mx3) have been identified in S. aurata, showing the three proteins a wide spectrum of antiviral activity. The structure of the three promoters (pMx1, pMx2 and pMx3) has been disclosed, and their response to IFN I, IPNV and VHSV indicated a clear induction of the three promoters, with some differences in the kinetics and magnitude of the response. Several studies evidenced the important role of Mx transcription regulation on virus-host interaction: i) Mx promoters can respond to both IFN I and IFN II, thus Mx might be the link between innate and adaptive immunity; ii) Mx activation is blocked by several viruses, thus Mx transcription is the target of their IFN I antagonistic activity; and iii) A fish cell line modified with the promoter of a fish Mx gene was used to measure viraemia in serum with high sensitivity. Therefore, assessing the regulatory mechanisms controlling the transcription of fish Mx genes could significantly contribute to both, understanding virus-host interactions, and designing strategies to control viral infections. In our case, this approach can also give light to understand the successful antiviral strategies developed by gilthead seabream in nature. Thus, the purpose of the present work was to develop three stable transgenic cell lines expressing the firefly luciferase gene under the control of the gilthead seabream Mx promoters. These in vitro systems were established and their response to poly I:C, and to two viral infections was characterized. In the case of IPNV, a clear antagonistic activity was observed for pMx2, as the activity of the promoter was 78.53% lower, however, this effect was not observed for pMx1 and pMx3. When cells were infected with VHSV, no changes in the promoters’ activity were detected, thus indicating that seabream Mx promoters are not targeted by VHSV antagonistic activity. These results confirm the specificity of the interactions between each virus/promoter combination, and support the use of the three cell lines developed as useful tools to characterize virus-host interactions in this species. Further studies aimed at the identification of the molecular mechanisms behind our observations will allow us to get more insight into this complex system.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Eficacia de haloxifop-r-metil con distintos coadyuvantes

En Argentina se han confirmado trece biotipos de malezas resistentes a glifosato, ocho son gramíneas y para su control se recomiendan herbicidas como haloxifop-R-metil con el agregado de aceite mineral. En el mercado se ofrecen otros aditivos para sustituir el aceite mineral que tendrían igual o mayor efectividad y menores costos. El objetivo de este trabajo fue evaluar la eficacia de haloxifop-R-metil con diferentes coadyuvantes (aceite mineral, nonilfenol etoxilado, ésteres metílicos de aceites vegetales, alcohol lineal etoxilado y alcohol oxo polioxietilenado) sobre avena 40 días después de la siembra. Se determinó la eficacia mediante la evaluación de la senescencia y peso seco de las plantas. La mejor acción herbicida de haloxifop-R-metil fue con el agregado de aceite mineral.In Argentina, thirteen biotypes of glyphosate-resistant weeds have been confirmed, eight of the-se are grasses. To control grassy weeds herbicides such as haloxifop-R-methyl with the addition of mineral oil is recommended. Other additives to replace the mineral oil are currently offered in the market with equal or greater eficcacy and lower costs. The aim of this work was to evaluate the eficcacy of haloxifop-R-methyl with different adjuvants (mineral oils, ethoxylated nonylphenol, methyl esters of vegetable oil, ethoxylated linear alcohol and oxo polyoxyethylenated alcohol), applied in oats 40 days after sowing. Eficcacy was determined by senescence and dry weight of the plants. The best herbicide action of haloxifop-R-methyl was with the use of mineral oil as an additive.EEA ReconquistaFil: Sanchez, P. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias. Cátedra de Sanidad Vegetal; ArgentinaFil: Lutz, Alejandra. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias. Cátedra de Sanidad Vegetal; ArgentinaFil: Magliano, M. Florencia. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias. Cátedra de Sanidad Vegetal; ArgentinaFil: Menapace, Pablo Conrado. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Reconquista; ArgentinaFil: Scotta, Roberto. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias. Cátedra de Sanidad Vegetal; Argentin

Gene Silencing of \u3ci\u3eArgonaute5\u3c/i\u3e Negatively Affects the Establishment of the Legume-Rhizobia Symbiosis

The establishment of the symbiosis between legumes and nitrogen-fixing rhizobia is finely regulated at the transcriptional, posttranscriptional and posttranslational levels. Argonaute5 (AGO5), a protein involved in RNA silencing, can bind both viral RNAs and microRNAs to control plant-microbe interactions and plant physiology. For instance, AGO5 regulates the systemic resistance of Arabidopsis against Potato Virus X as well as the pigmentation of soybean (Glycine max) seeds. Here, we show that AGO5 is also playing a central role in legume nodulation based on its preferential expression in common bean (Phaseolus vulgaris) and soybean roots and nodules. We also report that the expression of AGO5 is induced after 1 h of inoculation with rhizobia. Down-regulation of AGO5 gene in P. vulgaris and G. max causes diminished root hair curling, reduces nodule formation and interferes with the induction of three critical symbiotic genes: Nuclear Factor Y-B (NF-YB), Nodule Inception (NIN) and Flotillin2 (FLOT2). Our findings provide evidence that the common bean and soybean AGO5 genes play an essential role in the establishment of the symbiosis with rhizobia

Injection of oxygenated Persian Gulf Water into the southern Bay of Bengal

Persian Gulf Water (PGW) is an oxygenated, high-salinity water mass that has recently been detected in the Bay of Bengal (BoB). However, little is known about the transport pathways of PGW into the BoB. Ocean glider observations presented here demonstrate the presence of PGW in the southwestern BoB. Output from an ocean reanalysis product shows that this PGW signal is associated with a northward-flowing filament of high-salinity water. Particle tracking experiments reveal two pathways: one in the eastern Arabian Sea that takes a minimum of 2 years and another in the western Arabian Sea that takes a minimum of 3 years. The western pathway connects to the BoB via equatorial currents. The greatest influx of PGW occurs between 82° and 87°E during the southwest monsoon. We propose that injection of PGW to the BoB oxygen minimum zone (OMZ) contributes to keeping oxygen concentrations in the BoB above the level at which denitrification occurs

Imaging land subsidence in the Guadalentín River Basin (SE Spain) using Advanced Differential SAR Interferometry

Aquifer overexploitation can lead to the irreversible loss of groundwater storage caused by the compaction or consolidation of unconsolidated fine-grained sediments resulting in land subsidence. Advanced Differential SAR Interferometry (A-DINSAR) is particularly efficient to monitor progressive ground movements, making it an appropriate method to study depleting aquifers undergoing overexploitation and land subsidence. The Guadalentín River Basin (Murcia, Spain) is a widely recognized subsiding area that exhibits the highest rates of groundwater-related land subsidence recorded in Europe (>10 cm/yr). The basin covers an extension of more than 500 km2 and is underlain by an overexploited aquifer-system formed by two contiguous hydraulically connected units (Alto Guadalentín and Bajo Guadalentín). Although during the last years the piezometric levels have partially stabilized, the ongoing aquifer-system deformation is evident and significant, as revealed by the A-DInSAR analysis presented. In this work, we submit the first vertical and horizontal (E-W) decomposition results of the LOS velocity and displacement time series of the whole Guadalentín Basin obtained from two datasets of Sentinel-1 SAR acquisitions in ascending and descending modes. The images cover the period from 2015 to 2021 and they were processed using the Parallel Small BAseline Subset (P-SBAS) implemented by CNRIREA in the Geohazards Exploitation Platform (GEP) on-demand web tool, which is funded by the European Space Agency. The output ascending and descending measurement points of P-SBAS lie on the same regular grid, which is particularly suited for the geometrical decomposition. Time series displacements are compared to a permanent GNSS station located in the Bajo Guadalentín basin.This study has received funding in framework of the RESERVOIR project (Sustainable groundwater RESources managEment by integrating eaRth observation deriVed monitoring and flOw modelIng Results), funded by the Partnership for Research and Innovation in the Mediterranean Area (PRIMA) programme supported by the European Union (Grant Agreement 1924; https://reservoir-prima.org/). The study has also been supported by the Grant FPU19/03929 (funded by MCIN/AEI/10.13039/501100011033 and by “FSE invests in your future”); the Project CGL2017-83931-C3-3-P (funded by MCIN/ AEI/10.13039/501100011033 and by “ERDF A way of making Europe”); the ESA-MOST China DRAGON-5 Project (ref. 59339) and the SARAI Project PID2020-116540RB-C22 (funded by MCIN/AEI/10.13039/501100011033). Copernicus Sentinel-1 IW SAR data were provided and processed in ESA’s Geohazards Exploitation Platform (GEP), in the framework of the GEP Early Adopters Programme

Spatial and temporal variability of solar penetration depths in the Bay of Bengal and its impact on SST during the summer monsoon

Chlorophyll has long been known to influence air–sea gas exchange and CO2 drawdown. But chlorophyll also influences regional climate through its effect on solar radiation absorption and thus sea surface temperature (SST). In the Bay of Bengal, the effect of chlorophyll on SST has been demonstrated to have a significant impact on the Indian summer (southwest) monsoon. However, little is known about the drivers and impacts of chlorophyll variability in the Bay of Bengal during the southwest monsoon. Here we use observations of downwelling irradiance measured by an ocean glider and three profiling floats to determine the spatial and temporal variability of solar absorption across the southern Bay of Bengal during the 2016 summer monsoon. A two-band exponential solar absorption scheme is fitted to vertical profiles of photosynthetically active radiation to determine the effective scale depth of blue light. Scale depths of blue light are found to vary from 12 m during the highest (0.3–0.5 mg m−3) mixed-layer chlorophyll concentrations to over 25 m when the mixed-layer chlorophyll concentrations are below 0.1 mg m−3. The Southwest Monsoon Current and coastal regions of the Bay of Bengal are observed to have higher mixed-layer chlorophyll concentrations and shallower solar penetration depths than other regions of the southern Bay of Bengal. Substantial sub-daily variability in solar radiation absorption is observed, which highlights the importance of near-surface ocean processes in modulating mixed-layer chlorophyll. Simulations using a one-dimensional K-profile parameterization ocean mixed-layer model with observed surface forcing from July 2016 show that a 0.3 mg m−3 increase in chlorophyll concentration increases sea surface temperature by 0.35 ∘C in 1 month, with SST differences growing rapidly during calm and sunny conditions. This has the potential to influence monsoon rainfall around the Bay of Bengal and its intraseasonal variability