Long-term (2009–2012) data from ground-based measurements of aerosol black carbon (BC) from a semi-urban site, Pantnagar (29.0°N, 79.5°E, 231 m amsl), in the Indo-Gangetic Plain (IGP) near the ...Himalayan foothills are analyzed to study the regional characterization. Large variations are seen in BC at both diurnal and seasonal scales, associated with the mesoscale and synoptic meteorological processes, and local/regional anthropogenic activities. BC diurnal variations show two peaks (morning and evening) arising from the combined effects of the atmospheric boundary layer (ABL) dynamics and local emissions. The diurnal amplitudes as well as the rates of diurnal evolution are the highest in winter season, followed by autumn, and the lowest in summer-monsoon. BC exhibits nearly an inverse relation with mixing layer depth in all seasons; being strongest in winter (R2 = 0.89) and weakest (R2 = 0.33) in monsoon (July–August). Unlike BC, co-located aerosol optical depths (AOD) and aerosol absorption are highest in spring over IGP, probably due to the presence of higher abundances of aerosols (including dust) above the ABL (in the free troposphere). AOD (500 nm) showed annual peak (>0.6) in May–June, dominated by coarse mode, while fine mode aerosols dominated in late autumn and early winter. Aerosols profiles from CALIPSO show highest values close to the surface in winter/autumn, similar to the feature seen in surface BC, whereas at altitudes > 2 km, the extinction is maximum in spring/summer. WRF-Chem model is used to simulate BC temporal variations and then compared with observed BC. The model captures most of the important features of the diurnal and seasonal variations but significantly underestimated the observed BC levels, suggesting improvements in diurnal and seasonal varying BC emissions apart from the boundary layer processes.
•A complete seasonal variation of BC from a semi-urban site in the IGP region.•Large diurnal and seasonal variation with maximum amplitude and levels in winter.•Surface BC is maximum in winter, unlike emission estimates showing spring maxima.•Unlike BC, CALIPSO extinctions at higher height and AOD reveal higher values in spring.•WRF-Chem simulated BC shows important features but underestimate observations.
Cholecystectomy is one of the commonest general surgical procedures performed all over India. The risk of bile duct injury (BDI) during laparoscopic cholecystectomy is two to three times higher than ...during open cholecystectomy. The worldwide incidence of bile duct injury is 0.5% or 1 in 200 cases. BDI and its consequences result in significant morbidity and may even cause mortality. BDI increases the cost of treatment and is a common reason for a medicolegal suit against the surgeons. To minimize the incidence of BDI and to manage it timely and appropriately, a set of guidelines was deemed necessary by a group of senior surgeons during a Society of Endoscopic and Laparoscopic Surgeons of India (SELSI) meeting in 2016. Guidelines for “Safe Laparoscopic Cholecystectomy” and bile duct injury management formulated by other international societies are already available. The applicability of these guidelines to Indian subjects especially in small peripheral centers was limited. Hence, a decision was taken to form a set of guidelines for general surgeons with basic laparoscopic skills with little or no advanced laparoscopic skills. Those working in a solo practice, nursing homes, and small private hospitals at talukas or districts should have “Safe Cholecystectomy” guidelines and management of BDI suitable to their situation. These guidelines were formed after three consensus meetings and have been approved by a SELSI Expert Group.
The present study aimed to evaluate the effect of the methanolic extract of
Hygrophila auriculata
(Schumach.) Heine, Acanthaceae, in obesity-induced insulin resistant rats. The effect of the extract ...on oxidative stress, membrane stability, and hepatic heat shock protein70 (Hsp70) modulation was carried out to determine its plausible mechanism of action in insulin resistant model. To test the cellular antioxidant potential and effect on membrane permeabilization and stability, the extract was tested in H
2
O
2
-induced oxidative stress and membrane damage in wild-type and knockout yeast strains. Methanolic extract of
H. auriculata
was further tested on high-fat fed/low-dose streptozotocin-induced diabetic rats. The effect of methanolic extract on parameters like body weight, insulin resistance, glucose levels, glucose tolerance, lipid profile, oxidative stress marker, and hepatic Hsp70 was analyzed in animals. Methanolic extract of
H. auriculata
was characterized using a high-resolution liquid chromatography-mass spectrometer (LC-MS/MS). The oxidative damage and membrane permeability induced by H
2
O
2
in both wild and knockout strains was reversed by methanolic extract treatment. In obese rats, the methanolic extract treatment significantly (
p
< 0.05) reduced insulin resistance, improved glycemic status, glucose tolerance, lipid profile, antioxidant level, and upregulated hepatic Hsp70 (
p
< 0.05). LC-MS/MS analysis of the methanolic extract showed the presence of cosmosin (apigetrin), pectolinarin, 3,4-dihydroxy phenylglycol and rhamnetin. The positive effect of the the methanolic extract on insulin resistance is attributed to its cytoprotective effect due to its antioxidant activity, membrane stabilization effect, and activation of the cytoprotective protein, Hsp70. The significant antioxidant activity of methanolic extract in yeast assay is substantiated by its effect on all the parameters of IR in rats.
Graphical Abstract
Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides that lack significant protein coding potential and have been shown to regulate various biological processes. This study was ...designed to identify lncRNAs in coconut and their role in the process of somatic embryogenesis in coconut, a crop with high recalcitrance to in vitro culture. RNA-Seq data of coconut embryogenic calli of the West Coast Tall cultivar was exploited for in silico prediction of lncRNA. From a total of 6328 transcripts, which were annotated as uncharacterised or with no homology hits with the existing database, 5110 putative lncRNAs are identified. We also studied the relationship between lncRNAs, microRNAs (miRNAs) and mRNAs and found that some of the lncRNAs act as miRNA precursors, some as potential miRNA targets and some function as endogenous target mimics (eTMs) for miRNAs. Real-time quantitative PCR confirmed that 10 selected lncRNAs showed significant differences in the expression pattern in different stages of coconut somatic embryogenesis. Our results suggest the existence of diverse lncRNAs in coconut embryogenic calli, some of which are differentially expressed. The information generated in this study could be of great value in understanding the molecular mechanisms governing somatic embryogenesis in coconut.
Cholecystectomy is one of the most common general surgical operations performed worldwide. The risk of bile duct injury (BDI) during laparoscopic cholecystectomy is two to three times higher than ...during open cholecystectomy. The worldwide incidence of bile duct injury is 0.5% or 1 in 200 cases. BDI and its consequences result in significant morbidity and may even cause mortality; it also increases the cost of treatment and can be a common reason for medico-legal suits against the surgeons. To minimize the incidence of BDI and to manage it timely and appropriately, a set of guidelines was deemed necessary by a group of senior surgeons during a Society of Endoscopic and Laparoscopic Surgeons of India (SELSI) meeting in 2016. Guidelines for “Safe Laparoscopic Cholecystectomy” and bile duct injury management formulated by other international societies are already available. The applicability of these guidelines to Indian subjects, especially in small peripheral centers, was limited. Hence, a decision was taken to form a set of guidelines for general surgeons with basic laparoscopic skills with little or no advanced laparoscopic skills. Those working in a solo practice, nursing homes, and small private hospitals at talukas or districts should have “Safe Cholecystectomy” guidelines and management of BDI suitable to their situation. These guidelines were formed after three consensus meetings and have been approved by a SELSI Expert Group.
Most environmental parameters have no consistent effect on the expression of bacterial genes responsible for their virulence. However, as fish are poikilothermic, the possibility of temperature ...variation having a pronounced effect on the expression of virulence-associated gene(s) of bacteria infecting the host needs to be investigated. In this study, the diversity of virulence genes in seven Aeromonas hydrophila isolates collected from diseased fish from different parts of India was characterized, and the effect of temperature variation on the extent of expression of their virulence was investigated. All bacterial isolates were screened for a total of nine bacterial virulent genes {aerolysin, hemolysin, cytoen, outer membrane protein TS (Omp TS), elastase, flagellin, lipase, β hemolysin and type 3 secretion system}, and the diversity in their presence or absence were marked at a particular in vitro condition. Three bacterial isolates (nos. 1, 7 and 2) were selected for further study, based on their ability to cause varied mortalities (20–100%) in Labeo rohita juveniles in intraperitoneal challenge study. Further, three isolates were injected intraperitoneally into L. rohita fingerlings at three different temperatures (i.e., 20, 28 and 37 °C) and at 6 h post-challenge, the kidney samples were collected to measure the levels of all nine bacterial virulence genes using semi-quantitative PCR. The maximum level of amplicons of virulence genes in all three A. hydrophila isolates was noticed at 28 °C as compared to 37 °C and 20 °C. It was also observed that haemolysin played a more prominent role in the expression of virulence, when compared to cytoen gene. Hence, it was concluded that water temperature does play a crucial role in governing virulence gene expression, and a temperature of 28 °C would be considered as suitable for looking into the pathogenicity of A. hydrophila for conducting any challenge study with this organism in tropical environment.
•Studied A. hydrophila virulence related genes in in vitro and in vivo pathogenicity.•Investigated pathogenicity of A. hydrophila at varied water temperatures in L.rohita.•T3SS identified as a possible marker for identification of pathogenic isolates of A. hydrophila.
Non-coding RNA (ncRNA)-based SSR markers are highly useful in molecular breeding as ncRNAs play a significant role in gene regulation. In the present study, for the first time in coconut, we have ...identified 597 ncRNA-derived SSR markers, including 509 long non-coding RNASSRs (lncRNASSRs) and 88 micro RNASSRs (miRNASSRs). Of these, 20 primers (10 each from lncRNA-SSR and miRNA-SSR) were selected, screened on 6 coconut accessions, and 50% produced polymorphic fragments. These 10 polymorphic primers were used for genotyping 96 palms of 16 coconut accessions, comprising eight tall and dwarf accessions each. The number of alleles ranged from 2 to 9 per SSR marker, with an average of 4.6 alleles per locus. The average heterozygosity and Shannon index were 0.5 and 1.1, respectively, suggesting that ncRNA-SSRs show high polymorphism level. Distance-based cluster analyses revealed that all the tall and dwarf accessions were differentiated and grouped in different clusters. The study demonstrates the usefulness of ncRNA-based SSR markers for assessing genetic diversity and genetic improvement in coconut.
This study examines an unexpected and extreme positive ionospheric response to a minor magnetic storm on August 5, 2019 by using global ionosphere specification (GIS) 3D electron density profiles ...obtained by assimilating radio occultation total electron content (TEC) measurements of the recently launched FORMOSAT‐7/COSMIC‐2 satellites, and ground‐based global navigation satellite system (GNSS) TEC. The results reveal ∼300% enhancement of equatorial ionization anomaly (EIA) crests, appearing over 200–300 km altitudes, and a much intense localized density enhancement over the European sector. These are the most intense ionospheric response that has ever been detected for a small magnetic storm with Dst ∼ −53 nT (SYM‐H ∼ −64 nT). The enhancements are validated by using global ionosphere map (GIM) TEC and ground‐based GNSS TEC. The GIS vertical electron density structures during the storm are examined to understand the physical processes giving rise to such an intense ionosphere response during deep solar minimum conditions when the background electron density is very low. Altitude variations and poleward shifts of the locations of the EIA crests indicate that prompt penetration electric fields (PPEF) play an important role in producing the observed positive storm responses, with the storm‐induced equatorward circulation supporting the plasma accumulation against recombination losses. Additional physical mechanisms are required to fully explain the unexpected electron density enhancements for this minor storm event.
Plain Language Summary
Ionospheric measurements by the new FORMOSAT‐7/COSMIC‐2 mission detected extreme and unexpected electron density enhancements during a weak magnetic storm on August 5, 2019. The electron density increased by >300% over Asia and Africa compared to previous day's values, and over Europe the increase was about 800%. Scientists previously showed large electron density increase when major magnetic storms occur, but such intense enhancements by a weak magnetic storm is not reported before. This may be due to the lack of continuous global electron density measurements previously. Using FORMOSAT‐7/COSMIC‐2 satellite GPS data, we have developed 3D global ionospheric electron densities for every hour on each day, and for the first‐time measurements are now available to study such variations. The new observations show that when solar activity is very low, a weak magnetic storm could produce very large variations, disrupting the ionosphere similar to that during severe magnetic storms. This study demonstrates the potential of FORMOSAT‐7/COSMIC‐2 measurements to capture such electron density variations. Detailed analysis shows that the magnetic storm modified electric field and wind, which contributed to the density enhancements. The results also suggest additional physical processes during magnetic storms in low solar activity periods than previously considered.
Key Points
Global 3D ionosphere built from FORMOSAT‐7/COSMIC‐2 and GNSS data shows extreme positive effects during a minor magnetic storm (Dst ∼ −53 nT)
Dayside low‐latitude/midlatitude ionosphere shows storm‐time enhancement in total electron content by ∼200% and in density at 200–300 km by ∼300%
Along with penetration electric field and storm‐time wind, rapid thermosphere expansion and low‐latitude downwelling could also be important
A giant ionospheric hole was simultaneously detected in the in situ measurements of FORMOSAT-7/COSMIC-2 (F7/C2), Ionospheric Connection Explorer (ICON), Swarm missions, and ground-based total ...electron content (TEC) by global navigation satellite system receivers, and F7/C2 Global Ionosphere Specification (GIS) data near Tonga, following the explosive volcano eruption on 15 January 2022. The TEC maps displayed the huge depletions that developed near Tonga after the eruption and gradually evolved. The ICON IVM, F7/C2 IVM and Swarm-LP detected large depletions not only near Tonga, but also in the EIA trough region. The GIS observations clearly show the ionospheric hole that extends spatially near Tonga, especially strongly south/southward. The simultaneous observations showed that the ionosphere hole near Tonga combined with the EIA trough and finally evolved into a giant ionosphere hole around 07 UT. The ionospheric hole, which occurred at 05 UT near Tonga, extended over a wide area of 160°-200°E and 25°S-20°N and lasted for about 11 h. The F7/C2 and ICON satellites overpasses showed large ion density depletions by the hole at orbit altitudes, accompanied by enhancements in ion temperature and field-aligned and perpendicular ion drift. Such a long-lasting giant ionospheric hole by a seismic event has not been reported earlier, creating a unique ionospheric environment near Tonga after the eruption. The strong successive impulses by multiple volcano eruptions, together with O/N
2
decrease in the summer hemisphere, interhemispheric wind, and water vapor injection into high altitudes apparently yielded such a giant ionospheric hole, 4–6 times larger than that observed during the Tohoku earthquake.
Graphical Abstract
Key points
The simultaneous measurements reveal the evolution of the ionospheric hole after the Tonga volcanic eruption.
The ionospheric hole that had occurred near Tonga merged with the EIA trough depletion in the northern hemisphere, forming a giant ionospheric hole.
The long-lasting giant ionospheric hole is caused by impulsive pressure, trans-equatorial wind, O/N2 depletion, and water vapor injection.
CME front and severe space weather Balan, N.; Skoug, R.; Tulasi Ram, S. ...
Journal of geophysical research. Space physics,
December 2014, Letnik:
119, Številka:
12
Journal Article
Recenzirano
Odprti dostop
Thanks to the work of a number of scientists who made it known that severe space weather can cause extensive social and economic disruptions in the modern high‐technology society. It is therefore ...important to understand what determines the severity of space weather and whether it can be predicted. We present results obtained from the analysis of coronal mass ejections (CMEs), solar energetic particle (SEP) events, interplanetary magnetic field (IMF), CME‐magnetosphere coupling, and geomagnetic storms associated with the major space weather events since 1998 by combining data from the ACE and GOES satellites with geomagnetic parameters and the Carrington event of 1859, the Quebec event of 1989, and an event in 1958. The results seem to indicate that (1) it is the impulsive energy mainly due to the impulsive velocity and orientation of IMF Bz at the leading edge of the CMEs (or CME front) that determine the severity of space weather. (2) CMEs having high impulsive velocity (sudden nonfluctuating increase by over 275 km s−1 over the background) caused severe space weather (SvSW) in the heliosphere (failure of the solar wind ion mode of Solar Wind Electron Proton Alpha Monitor in ACE) probably by suddenly accelerating the high‐energy particles in the SEPs ahead directly or through the shocks. (3) The impact of such CMEs which also show the IMF Bz southward from the leading edge caused SvSW at the Earth including extreme geomagnetic storms of mean DstMP < −250 nT during main phases, and the known electric power outages happened during some of these SvSW events. (4) The higher the impulsive velocity, the more severe the space weather, like faster weather fronts and tsunami fronts causing more severe damage through impulsive action. (5) The CMEs having IMF Bz northward at the leading edge do not seem to cause SvSW on Earth, although, later when the IMF Bz turns southward, they can lead to super geomagnetic storms of intensity (Dstmin) less than even −400 nT.
Key Points
Impulsive energy at CME front causes severe space weather (SvSW) in heliosphere
Impulsive energy and IMF Bz southward at the CME front causes SvSW at the Earth
Northward IMF Bz at the CME front causes normal space weather at the Earth
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