Direct observation of large temperature fluctuations during DNA thermal denaturation

In this paper we report direct measurement of large low frequency temperature fluctuations in double stranded (ds) DNA when it undergoes thermal denaturation transition. The fluctuation, which occurs only in the temperature range where the denaturation occurs, is several orders more than the expected equilibrium fluctuation. It is absent in single stranded (ss) DNA of the same sequence. The fluctuation at a given temperature also depends on the wait time and vanishes in a scale of few hours. It is suggested that the large fluctuation occurs due to coexisting denaturated and closed base pairs that are in dynamic equilibrium due to transition through a potential barrier in the scale of 25-30k_{B}T_{0}(T_{0}=300K).Comment: 4 pages, 5 figures, Replaced with revised versio

Interlayer Registry Determines the Sliding Potential of Layered Metal Dichalcogenides: The case of 2H-MoS2

We provide a simple and intuitive explanation for the interlayer sliding energy landscape of metal dichalcogenides. Based on the recently introduced registry index (RI) concept, we define a purely geometrical parameter which quantifies the degree of interlayer commensurability in the layered phase of molybdenum disulphide (2HMoS2). A direct relation between the sliding energy landscape and the corresponding interlayer registry surface of 2H-MoS2 is discovered thus marking the registry index as a computationally efficient means for studying the tribology of complex nanoscale material interfaces in the wearless friction regime.Comment: 13 pages, 7 figure

Electromechanical properties of suspended Graphene Nanoribbons

Graphene nanoribbons present diverse electronic properties ranging from semiconducting to half-metallic, depending on their geometry, dimensions and chemical composition. Here we present a route to control these properties via externally applied mechanical deformations. Using state-of-the-art density functional theory calculations combined with classical elasticity theory considerations, we find a remarkable Young's modulus value of ~7 TPa for ultra-narrow graphene strips and a pronounced electromechanical response towards bending and torsional deformations. Given the current advances in the synthesis of nanoscale graphene derivatives, our predictions can be experimentally verified opening the way to the design and fabrication of miniature electromechanical sensors and devices based on ultra-narrow graphene nanoribbons.Comment: 12 pages, 6 figure

Taking reincarnation seriously: Critical discussion of some central ideas from John Hick

Reincarnation has not been entirely neglected in the philosophy of religion but it has not always been taken seriously or carefully discussed in relation to its role in believers’ lives. John Hick is exceptional insofar as he gave sustained attention to the belief, at least as it features in the philosophies of Vedānta and Buddhism. While acknowledging the value of Hick’s recognition of the variety of reincarnation beliefs, this article critically engages with certain aspects of his approach. It argues that Hick’s search for a ‘criterion’ of reincarnation is misguided, and that his distinction between ‘factual’ and ‘mythic’ forms of the doctrine is over-simplifying

Collapse of the charge-ordering state at high magnetic fields in the rare-earth manganite Pr<SUB>0.63</SUB>Ca<SUB>0.37</SUB>MnO<SUB>3</SUB>

We have investigated the specific heat and resistivity of a single crystal of Pr<SUB>0.63</SUB>Ca<SUB>0.37</SUB>MnO<SUB>3</SUB> around the charge ordering (CO) transition temperature, T<SUB>CO</SUB>, in the presence of high magnetic fields (&#8804;12 T) which can melt the charge-ordered state. At low magnetic fields (&#8804;10 T), the manganite transforms from a charge-disordered paramagnetic insulating (PI) state to a charge-ordered insulating (COI) state as the temperature is lowered. The COI state becomes unstable beyond a threshold magnetic field and melts to a ferromagnetic metallic phase (FMM). This occurs for T&lt;T<SUB>CO</SUB>. However, above a critical field &#956;<SUB>0</SUB>H<SUP>&#8727;</SUP><SUB>&#961;</SUB>, the sample shows the onset of a metallic phase for T&gt;T<SUB>CO</SUB> and the COI transition occurs from a metallic phase. The onset temperature of the high-field metallic behavior decreases with an increase in the field and above a field &#956;<SUB>0</SUB>H<SUP>&#8727;</SUP>, the COI transition does not occur and the CO state ceases to occur at all T. The entropy change involved in the CO transition, &#916;S<SUB>CO</SUB>&#8776;1.6 J/mol K at 0 T, decreases with increasing field and eventually vanishes for a field &#956;<SUB>0</SUB>H<SUP>&#8727;</SUP>. The collapse of the CO state above &#956;<SUB>0</SUB>H<SUP>&#8727;</SUP> is thus associated with a collapse of the entropy that stabilizes the CO state

Laser Calorimetry Spectroscopy for ppm-level Dissolved Gas Detection and Analysis

In this paper we report a newly developed technique - laser calorimetry spectroscopy (LCS), which is a combination of laser absorption spectroscopy and calorimetry - for the detection of gases dissolved in liquids. The technique involves determination of concentration of a dissolved gas by irradiating the liquid with light of a wavelength where the gas absorbs, and measuring the temperature change caused by the absorbance. Conventionally, detection of dissolved gases with sufficient sensitivity and specificity was done by first extracting the gases from the liquid and then analyzing the gases using techniques such as gas chromatography. Using LCS, we have been able to detect ppm levels of dissolved gases without extracting them from the liquid. In this paper, we show the detection of dissolved acetylene in transformer oil in the mid infrared (MIR) wavelength (3021 nm) region