A
bstract
The recently introduced swampland criterion for de Sitter
17
can be viewed as a (hierarchically large) bound on the smallness of the slow roll parameter 𝜖
V
. This leads us to consider ...the other slow roll parameter
η
V
more closely, and we are lead to conjecture that the bound is not necessarily on 𝜖
V
, but on slow roll itself. A natural refinement of the de Sitter swampland conjecture is therefore that slow roll is violated at
O
(1) in Planck units in any UV complete theory. A corollary is that 𝜖
V
need not necesarily be
O
(1), if
η
V
≲
−
O
1
holds. We consider various tachyonic tree level constructions of de Sitter in IIA/IIB string theory (as well as closely related models of inflation), which superficially violate
17
, and show that they are consistent with this refined version of the bound. The phrasing in terms of slow roll makes it plausible why both versions of the conjecture run into trouble when the number of e-folds during inflation is high. We speculate that one way to evade the bound could be to have a large number of fields, like in
N
-flation.
Acute pancreatitis may be associated with both local and systemic complications. Systemic injury manifests in the form of organ failure, which is seen in approximately 20% of all cases of acute ...pancreatitis and defines “severe acute pancreatitis.” Organ failure typically develops early in the course of acute pancreatitis, but also may develop later due to infected pancreatic necrosis–induced sepsis. Organ failure is the most important determinant of outcome in acute pancreatitis. We review here the current understanding of the risk factors, pathophysiology, timing, impact on outcome, and therapy of organ failure in acute pancreatitis. As we discuss the pathophysiology of severe systemic injury, the distinctions between markers and mediators of severity are highlighted based on evidence supporting their causality in organ failure. Emphasis is placed on clinically relevant end points of organ failure and the mechanisms underlying the pathophysiological perturbations, which offer insight into potential therapeutic targets to treat.
In the present study adsorption of Cr(VI) from aqueous solutions onto different agricultural wastes, viz., sugarcane bagasse, maize corn cob and Jatropha oil cake under various experimental ...conditions has been studied. Effects of adsorbent dosage, Cr(VI) concentration, pH and contact time on the adsorption of hexavalent chromium were investigated. The concentration of chromium in the test solution was determined spectrophotometrically. FT-IR spectra of the adsorbents (before use and after exhaustion) were recorded to explore number and position of the functional groups available for the binding of chromium ions on to studied adsorbents. SEMs of the adsorbents were recorded to explore the morphology of the studied adsorbents. Maximum adsorption was observed in the acidic medium at pH 2 with a contact time of 60
min at 250
rpm stirring speed. Jatropha oil cake had better adsorption capacity than sugarcane bagasse and maize corn cob under identical experimental conditions. The applicability of the Langmuir and Freundlich adsorption isotherms was tested. The results showed that studied adsorbents can be an attractive low cost alternative for the treatment of wastewaters in batched or stirred mode reactors containing lower concentrations of chromium.
In the present study, effect of adsorbent dose, pH and agitation speed on nickel removal from aqueous medium using an agricultural waste biomass, Sugarcane bagasse has been investigated. Batch mode ...experiments were carried out to assess the adsorption equilibrium. The influence of three parameters on the removal of nickel was also examined using a response surface methodological approach. The central composite face-centered experimental design in response surface methodology (RSM) by Design Expert Version 6.0.10 (Stat Ease, USA) was used for designing the experiments as well as for full response surface estimation. The optimum conditions for maximum removal of nickel from an aqueous solution of 50
mg/L were as follows: adsorbent dose (1500
mg/L), pH (7.52) and stirring speed (150
rpm). This was evidenced by the higher value of coefficient of determination (
r
2
=
0.9873).
Abstract
In this study, we characterize the impacts of COVID-19 on air pollution using NO
2
and Aerosol Optical Depth (AOD) from TROPOMI and MODIS satellite datasets for 41 cities in India. ...Specifically, our results suggested a 13% NO
2
reduction during the lockdown (March 25–May 3rd, 2020) compared to the pre-lockdown (January 1st–March 24th, 2020) period. Also, a 19% reduction in NO
2
was observed during the 2020-lockdown as compared to the same period during 2019. The top cities where NO
2
reduction occurred were New Delhi (61.74%), Delhi (60.37%), Bangalore (48.25%), Ahmedabad (46.20%), Nagpur (46.13%), Gandhinagar (45.64) and Mumbai (43.08%) with less reduction in coastal cities. The temporal analysis revealed a progressive decrease in NO
2
for all seven cities during the 2020 lockdown period. Results also suggested spatial differences, i.e., as the distance from the city center increased, the NO
2
levels decreased exponentially. In contrast, to the decreased NO
2
observed for most of the cities, we observed an increase in NO
2
for cities in Northeast India during the 2020 lockdown period and attribute it to vegetation fires. The NO
2
temporal patterns matched the AOD signal; however, the correlations were poor. Overall, our results highlight COVID-19 impacts on NO
2
, and the results can inform pollution mitigation efforts across different cities of India.
This review describes our laboratory’s efforts to develop transition metal-catalyzed cross-couplings of several unconventional phenol-based electrophiles. Specifically, we highlight herein the ...following four key transformations: (a) nickel-catalyzed Suzuki–Miyaura couplings of aryl pivalates, carbamates, and sulfamates to construct sp2–sp2 C–C bonds; (b) iron-catalyzed Kumada couplings of aryl carbamates and sulfamates for the assembly of sp2–sp3 C–C bonds; (c) nickel-catalyzed amination reactions of carbamates and sulfamates to build aryl C–N bonds; and (d) nickel-catalyzed reductive cleavage reactions of aryl carbamates to achieve aryl deoxygenation and a rare method for cine substitution. We expect this review will enable the greater use of unconventional phenol-based cross-coupling electrophiles in industrial settings.
Remote Sensing (RS) and Geographical Information System (GIS) play a crucial role to understand the division of groundwater, an important resource of water supply all over the world. In this present ...study, groundwater potential and recharge zone maps, are delineated for Loni and Morahi watersheds, Unnao and Rae Bareli district, Uttar Pradesh, India using RS, GIS and Multi-Criteria Decision Making (MCDM) techniques. The Satty’s Analytical Hierarchical Process (AHP) is used as a MCDM technique to normalise the weights of various thematic layers and their classes for delineating the groundwater potential and recharge zone maps. Thematic layers were integrated using weighted overlay in a GIS environment to generate groundwater potential and recharge zone maps. The output potential map is further classified into five zones on the basis of their histograms, viz., ‘very poor’, ‘poor’, ‘good’, ‘very good’ and ‘excellent’. The area falling in the excellent zone is about 150.93 km² (7.06 % of the total study area), which covers a major portion of the Ganga river. It discriminates the areas where the terrain is suitable for groundwater storage. However, the area falling in the very poor zone is about 372.03 km² (17.42 % of the total study area) and covers the Loni river south-eastern portion and some areas in north-eastern sides. Groundwater recharge map is classified into four zones namely; ‘most suitable’, ‘moderately suitable’, ‘poorly suitable’ and ‘not suitable’. Yield data of the 40 pumping wells are used to verify the groundwater potential zone map, and the results were found to be good.
Heterocyclic arynes, or hetarynes, have been studied for over 100 years. However, challenges associated with observing these reactive species, as well as developing synthetically useful methods for ...their generation and trapping, have limited their use. This review provides a brief historical perspective on the field of hetarynes, in addition to a discussion of pyridyne and indolyne methodologies. Moreover, this review highlights the use of pyridynes, indolynes, and related strained intermediates in natural product synthesis.
► We studied removal of cadmium from wastewater by column mode by a new adsorbent. ► Sunflower plant biomass has been converted into calcium–alginate beads. ► The metal removal is dependent on bed ...height, flow rate and metal concentration. ► The column can be used for three cycles.
The present study reports the use of sunflower waste carbon calcium–alginate beads (SWC-CAB) for cadmium removal from wastewater in continuous flow fixed bed columns. The experiments were conducted as a function of bed height, flow rate and initial Cd(II) concentration. The maximum biosorption capacity (23.6mg/g) was attained at 30cm bed height, 1.0mL/min flow rate and 10mg/L initial Cd(II) concentration. The Bohart – Adams model constants (N0 and K) were 7.7mg/L and 1×10−4L/mgh with 0.999 R2 value at 50% breakthrough time. The column regeneration efficiency after third cycle was 58.6% for cadmium.
This paper reports the recycling of nutrients by vermicomposting of cow dung (CD), poultry droppings (PD) and food industry sludge (FIS) employing earthworms (Eisenia fetida). A total of six ...vermicomposting units were established and dynamics of chemical and biological parameters has been studied for 13weeks. The waste mixture containing 50% CD+25% PD+25% FIS had better fertilizer value among studied waste combinations. At the end of experiment, vermicomposts showed decrease in pH and organic C, but increase in EC, total Kjeldhal N, total available P and total K contents. The C:N ratio of final vermicomposts also reduced to 10.7–12.7 from 22.8 to 56 in different waste combinations. The earthworms have good biomass gain and cocoon production in all vermicomposting units but CD alone and 50% CD+25% PD+25% FIS were better than other studied combinations.
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