763 research outputs found
Impact of cropping systems on soil properties, nutrient availability and their carbon sequestration potential in Shiwalik hills of Himachal Pradesh
The impact of cropping systems on soil properties, nutrient availability and their carbon sequestration potential was studied during the years 2014 and 2015 in Shiwalik hills of Himachal Pradesh. The four commonly occurring cropping systems namely vegetable, fruit, cereal crop and agroforestry were selected. Uncultivated land in the region was considered as control. In total, there were five treatments which were replicated six times under randomized block design. The study indicated that the cropping systems in the Shiwalik hills varied significantly (P=0.05) with respect to their impact on soil properties, nutrient availability and carbon sequestration potential. The pH and EC was in the range of 6.04 to 6.90 and 0.094 to 0.138 dSm-1, respectively and were normal in range. Organic carbon and bulk density in surface soils ranged from 8.06 to 9.70 g kg-1 and 1.19 to 1.34 Mg m-3, respectively. The available NPK was highest (267.21, 19.99, 172.42 kg ha-1) under vegetable based cropping system as compared to other systems. Carbon density in surface soil ranged from 11.33 to 15.39 Mg C ha-1 and total carbon sequestered upto 30cm soil depth ranged from 601.96 to 12646.29 Gg. The study indicated that in Shiwalik hills of Himachal Pradesh, the commonly occurring cropping systems did not influence the soil properties and nutrient availability adversely. Agroforestry based cropping system is having highest potential of sequestering soil carbon in Shiwalik hills. Therefore to adapt to changing climatic situation and to mitigate its effect in the region, agroforestry based cropping system need to be encouraged
Robustness of the transition against compositional and structural ageing in S/F/S heterostructures
We have studied the temperature induced thermodynamic transition in
Nb/PdNi/Nb Superconductor/Ferromagnetic/Superconductor (SFS) heterostructures
by microwave measurements of the superfluid density. We have observed a shift
in the transition temperature with the ageing of the heterostructures,
suggesting that structural and/or chemical changes took place. Motivated by the
electrodynamics findings, we have extensively studied the local structural
properties of the samples by means of X-ray Absorption Spectroscopy (XAS)
technique, and the compositional profile by Time-of-Flight Secondary Ion Mass
Spectrometry (ToF-SIMS). We found that the samples have indeed changed their
properties, in particular for what concerns the interfaces and the composition
of the ferromagnetic alloy layer. The structural and compositional data are
consistent with the shift of the transition toward the behaviour of
heterostructures with different F layers. An important emerging indication to
the physics of SFS is the weak relevance of the ideality of the interfaces:
even in aged samples, with less-than-ideal interfaces, the temperature-induced
transition is still detectable albeit at a different critical F
thickness.Comment: 11 pages, 9 figures, accepted for publication on Phys. Rev. B,
http://journals.aps.org/prb
On high-speed turning of a third-generation gamma titanium aluminide
Gamma titanium aluminides are heat-resistant intermetallic alloys predestined to be employed in components suffering from high mechanical stresses and thermal loads. These materials are regarded as difficult to cut, so this makes process adaptation essential in order to obtain high-quality and defect-free surfaces suitable for aerospace and automotive parts. In this paper, an innovative approach for longitudinal external high-speed turning of a third-generation Ti-45Al-8Nb- 0.2C-0.2B gamma titanium aluminide is presented. The experimental campaign has been executed with different process parameters, tool geometries and lubrication conditions. The results are discussed in terms of surface roughness/integrity, chip morphology, cutting forces and tool wear. Experimental evidence showed that, due to the high cutting speed, the high temperatures reached in the shear zone improve chip formation, so a crack-free surface can be obtained. Furthermore, the use of a cryogenic lubrication system has been identified in order to reduce the huge tool wear, which represents the main drawback when machining gamma titanium aluminides under the chosen process condition
Tamarind (Tamarindus indica linn.) and Sweet Sorghum (Sorghum bicolor L.Moench): their Potential Utilization in Phytotherapy
The use of botanical extracts and essential oil in skin care has been increasing due to greater demand on the part of consumers to use natural ingredients. Tamarind and Sweet Sorghum really have big potentials for reaching the public and showcasing its benefits , thus this study could encourage growers to raise more Tamarind and Sweet Sorghum in their areas not only as food but as a raw material in the production of natural products which are for health and wellness. Both Tamarind and Sweet Sorghum possess skin healing effect which may be attributed to their biologically active components. Tamarind possess to have bioflavonoids and alkaloids which occur in its leaves, pulp and bark. The bark contains tannin which are recommended for treatments of inflammation, ulceration and skin disease. Tamarind has Tartaric acid that makes it possible for tamarind to works wonders on oily skin with pimples and on sun-damaged. Sweet Sorghum on the other hand contains emulsion, a substance that can give a moisturizing effect on the skin. the majestic phytochemistry of Tamarind and Sweet Sorghum encouraged the researcher to produce and test the acceptability, efficacy and safety of different skin care products that are commonly needed by the community. The Tamarind Leaves soap was proven to be highly acceptable in terms of its color, odor, texture, hardness and overall appearance. Both the Tamarind soap and the Sweet Sorghum soap were safe and free from insoluble soap and fatty acid soap. The percent reduction of acne in using Tamarind soap, Sweet Sorghum and Commercial soap have similar effect on the tenth and twelve days of use. The initial means of the treatments ranges from 10.00 pustule to 2.00 pustule. After 12 days of treatment the mean decrease is zero or equivalent to 100% decrease in the number of acne. The result of this study maybe explained with the result on antibacterial property test ( against Staphylococcus A.) of Tamarind soap and Sweet Sorghum Soap. Tamarind soap with 8% extract was found to be most effective in reduction of pimples. The Tamarind shower gel and Sweet Sorghum shower gels were effective against Staphylococcus Aurous. Tamarind Bark Ointment was an effective anti – inflammatory agent particularly on swelling and redness as well as for wound healing. Tamarind scrub salt, shower gel and liniment were also highly acceptable and found to be safe and effective. Result on the acceptability of Sweet Sorghum natural products are comparable to the acceptability of Tamarind natural products. The development of technology for the Production of Natural Products from Tamarind and Sweet Sorghum is timely, considering the growing consciousness of consumers on safe, organic and healthy natural products. Likewise, this product diversification scheme can promote multi-uses and competitive of the Tamarind and Sweet Sorghum
Plasmonic lenses for ultrafast electron nanoemission
We show the capability of plasmonic lenses for next-generation ultrafast electron sources. Using electromagnetic simulations, we design structures capable of femtosecond, nanoscale electron pulses. Plasmonic properties of template-stripped gold prototypes are characterized using cathodoluminescence spectromicroscopy
Minor changes largely restore catalytic activity of archaeal RNase P RNA from Methanothermobacter thermoautotrophicus
The increased protein proportion of archaeal and eukaryal ribonuclease (RNase) P holoenzymes parallels a vast decrease in the catalytic activity of their RNA subunits (P RNAs) alone. We show that a few mutations toward the bacterial P RNA consensus substantially activate the catalytic (C-) domain of archaeal P RNA from Methanothermobacter, in the absence and presence of the bacterial RNase P protein. Large increases in ribozyme activity required the cooperative effect of at least two structural alterations. The P1 helix of P RNA from Methanothermobacter was found to be extended, which increases ribozyme activity (ca 200-fold) and stabilizes the tertiary structure. Activity increases of mutated archaeal C-domain variants were more pronounced in the context of chimeric P RNAs carrying the bacterial specificity (S-) domain of Escherichia coli instead of the archaeal S-domain. This could be explained by the loss of the archaeal S-domain's capacity to support tight and productive substrate binding in the absence of protein cofactors. Our results demonstrate that the catalytic capacity of archaeal P RNAs is close to that of their bacterial counterparts, but is masked by minor changes in the C-domain and, particularly, by poor function of the archaeal S-domain in the absence of archaeal protein cofactors
Design and testing of ultrafast plasmonic lens nanoemitters
Nanoscale electron pulses are increasingly in demand, including as probes of nanoscale ultrafast dynamics and for emerging light source and lithography applications. Using electromagnetic simulations, we show that gold plasmonic lenses as multiphoton photoemitters provide unique advantages, including emission from an atomically at surface, nanoscale pulse diameter regardless of laser spot size, and femtosecond-scale response time. We then present fabrication of prototypes with sub-nm roughness via e-beam lithography, as well as electro-optical characterization using cathodoluminescence spectromicroscopy. Finally, we introduce a DC photogun at LBNL built for testing ultrafast photoemitters. We discuss measurement considerations for ultrafast nanoemitters and predict that we can extract tens of pA photocurrent from a single plasmonic lens using a Ti:Sa oscillator. Altogether, this lays the groundwork to develop and test a broad class of plasmon-enhanced ultrafast nanoemitters
Acute Pressor Response to Psychosocial Stress Is Dependent on Endothelium‐Derived Endothelin‐1
Background
Acute psychosocial stress provokes increases in circulating endothelin‐1 (ET‐1) levels in humans and animal models. However, key questions about the physiological function and cellular source of stress‐induced ET‐1 remain unanswered. We hypothesized that endothelium‐derived ET‐1 contributes to the acute pressor response to stress via activation of the endothelin A receptor. Methods and Results
Adult male vascular endothelium‐specific ET‐1 knockout mice and control mice that were homozygous for the floxed allele were exposed to acute psychosocial stress in the form of cage switch stress (CSS), with blood pressure measured by telemetry. An acute pressor response was elicited by CSS in both genotypes; however, this response was significantly blunted in vascular endothelium‐specific ET‐1 knockout mice compared with control mice that were homozygous for the floxed allele. In mice pretreated for 3 days with the endothelin A antagonist, ABT‐627, or the dual endothelin A/B receptor antagonist, A‐182086, the pressor response to CSS was similar between genotypes. CSS significantly increased plasma ET‐1 levels in control mice that were homozygous for the floxed allele. CSS failed to elicit an increase in plasma ET‐1 in vascular endothelium‐specific ET‐1 knockout mice. Telemetry frequency domain analyses suggested similar autonomic responses to stress between genotypes, and isolated resistance arteries demonstrated similar sensitivity to α1‐adrenergic receptor‐mediated vasoconstriction. Conclusions
These findings specify that acute stress‐induced activation of endothelium‐derived ET‐1 and subsequent endothelin A receptor activation is a novel mediator of the blood pressure response to acute psychosocial stress
Novel Cardiac-Specific Biomarkers and the Cardiovascular Continuum
The concept of the cardiovascular continuum, introduced during the early 1990s, created a holistic view of the chain of events connecting cardiovascular-related risk factors with the progressive development of pathological-related tissue remodelling and ultimately, heart failure and death. Understanding of the tissue-specific changes, and new technologies developed over the last 25–30 years, enabled tissue remodelling events to be monitored in vivo and cardiovascular disease to be diagnosed more reliably than before. The tangible product of this evolution was the introduction of a number of biochemical markers such as troponin I and T, which are now commonly used in clinics to measure myocardial damage. However, biomarkers that can detect specific earlier stages of the cardiovascular continuum have yet to be generated and utilised. The majority of the existing markers are useful only in the end stages of the disease where few successful intervention options exist. Since a large number of patients experience a transient underlying developing pathology long before the signs or symptoms of cardiovascular disease become apparent, the requirement for new markers that can describe the early tissue-specific, matrix remodelling process which ultimately leads to disease is evident. This review highlights the importance of relating cardiac biochemical markers with specific time points along the cardiovascular continuum, especially during the early transient phase of pathology progression where none of the existing markers aid diagnosis
Evidence for a Novel Reaction Mechanism of a Prompt Shock-Induced Fission Following the Fusion of 78Kr and 40Ca Nuclei at E/A =10 MeV
An analysis of experimental data from the inverse-kinematics ISODEC
experiment on 78Kr+40Ca reaction at a bombarding energy of 10 AMeV has revealed
signatures of a hitherto unknown reaction mechanism, intermediate between the
classical damped binary collisions and fusion-fission, but also substantially
different from what is being termed in the literature as fast fission or quasi
fission. These signatures point to a scenario where the system fuses
transiently while virtually equilibrating mass asymmetry and energy and, yet,
keeping part of the energy stored in a collective shock-imparted and, possibly,
angular momentum bearing form of excitation. Subsequently the system fissions
dynamically along the collision or shock axis with the emerging fragments
featuring a broad mass spectrum centered around symmetric fission, relative
velocities somewhat higher along the fission axis than in transverse direction,
and virtually no intrinsic spin. The class of massasymmetric fission events
shows a distinct preference for the more massive fragments to proceed along the
beam direction, a characteristic reminiscent of that reported earlier for
dynamic fragmentation of projectile-like fragments alone and pointing to the
memory of the initial mass and velocity distribution.Comment: 5 PAGES, 6 FIGURE
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