3,430 research outputs found
Minimal Uncertainty in Momentum: The Effects of IR Gravity on Quantum Mechanics
The effects of the IR aspects of gravity on quantum mechanics is
investigated. At large distances where due to gravity the space-time is curved,
there appears nonzero minimal uncertainty in the momentum of a
quantum mechanical particle. We apply the minimal uncertainty momentum to some
quantum mechanical interferometry examples and show that the phase shift
depends on the area surrounded by the path of the test particle . We also put
some limits on the related parameters. This prediction may be tested through
future experiments. The assumption of minimal uncertainty in momentum can also
explain the anomalous excess of the mass of the Cooper pair in a rotating thin
superconductor ring.Comment: 8 pages, revised version accepted by PR
Gravitomagnetic Resonance Shift due to a Slowly Rotating Compact Star
The effect of a slowly rotating mass on a forced harmonic oscillator with two
degrees of freedom is studied in the weak field approximation. It is found that
according to the general theory of relativity there is a shift in the resonat
frequency of the oscillator which depends on the density and rotational
frequency of the gravitational source. The proposed shift is quite small under
normal physical situations however it is estimated that for compact x-ray
sources such as white dwarfs, pulsars, and neutron stars the shift is quite
appreciable.Comment: 8 pages, 2 figures, Accepted for Publication in Inter. Journal of
Modern Physics
Chaotic Accretion in a Non-Stationary Electromagnetic Field of a Slowly Rotating Compact Star
We investigate charge accretion in vicinity of a slowly rotating compact star
with a non-stationary electromagnetic field. Exact solutions to the general
relativistic Maxwell equations are obtained for a star formed of a highly
degenerate plasma with a gravitational field given by the linearized Kerr
metric. These solutions are used to formulate and then to study numerically the
equations of motion for a charged particle in star's vicinity using the
gravitoelectromagnetic force law. The analysis shows that close to the star
charge accretion does not always remain ordered. It is found that the magnetic
field plays the dominant role in the onset of chaos near the star's surface.Comment: 9 pages, 4 figure
Contextual perception under active inference
Human social interactions depend on the ability to resolve uncertainty about the mental states of others. The context in which social interactions take place is crucial for mental state attribution as sensory inputs may be perceived differently depending on the context. In this paper, we introduce a mental state attribution task where a target-face with either an ambiguous or an unambiguous emotion is embedded in different social contexts. The social context is determined by the emotions conveyed by other faces in the scene. This task involves mental state attribution to a target-face (either happy or sad) depending on the social context. Using active inference models, we provide a proof of concept that an agent’s perception of sensory stimuli may be altered by social context. We show with simulations that context congruency and facial expression coherency improve behavioural performance in terms of decision times. Furthermore, we show through simulations that the abnormal viewing strategies employed by patients with schizophrenia may be due to (i) an imbalance between the precisions of local and global features in the scene and (ii) a failure to modulate the sensory precision to contextualise emotions
Conotoxins: structure, therapeutic potential and pharmacological applications.
Cone snails, also known as marine gastropods, from Conus genus produce in their venom a diverse range of small pharmacologically active structured peptides called conotoxins. The cone snail venoms are widely unexplored arsenal of toxins with therapeutic and pharmacological potential, making them a treasure trove of ligands and peptidic drug leads. Conotoxins are small disulfide bonded peptides, which act as remarkable selective inhibitors and modulators of ion channels (calcium, sodium, potassium), nicotinic acetylcholine receptors, noradrenaline transporters, N-methyl-D-aspartate receptors, and neurotensin receptors. They are highly potent and specific against several neuronal targets making them valuable as research tools, drug leads and even therapeutics. In this review, we discuss their gene superfamily classification, nomenclature, post-translational modification, structural framework, pharmacology and medical applications of the active conopeptides. We aim to give an overview of their structure and therapeutic potential. Understanding these aspects of conopeptides will help in designing more specific peptidic analogues
Pengaruh Perendaman Larutan KOH Dan NaOH Terhadap Kualitas Alginat Rumput Laut Sargassum Polycycstum C.A. Agardh
Sargassum polycystum seaweed is a type of brown algae that contains alginate. Alginate from S. polycystum did not optimally and alginate has an importnat role from a variety of industries. Alginate ekstraction obtained by submersion wes using NaOH and KOH solvent, then continued using Na2CO3 solvent. The purpose of this research was to determine the effect of immersion with KOH and NaOH with concentration 0,3%, 0,5% and 0,7% solution to the quality alginate from brown seaweed S. polycystum. Experimental design used was Rancangan Acak Lengkap (RAL). The results showed that aging of the KOH solution has a lower water content and higher viscosity than NaOH solution. The concentration of the solution used also affects the yield, moisture content, ash content and viscosity alginate S. polycystum. The higher concentration of the solution then the yield, moisture content and lower ash content, while viscosity alginate increased. The best results obtained in the treatment with a solution of KOH concentration of 0.7%
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Chemical Characterization and Source Apportionment of PM2.5 in Rabigh, Saudi Arabia
A nanocrystal technology: to enhance solubility of poorly water soluble drugs
Most of the recently developed new chemical entities are poorly water soluble and they create major problems during formulation and development of new dosage form and due to poor solubility and poor bioavailability. The drugs belong to BCS class II and class IV has problem of solubility, to overcome the solubility problem nanotechnology is most useful technique. In this review article the main focus on Nanocrystals and various techniques used for preparation of Nanocrystals. Drug nanocrystals consists pure poorly water soluble drugs without any matrix material which means that it is carrier free drug delivery. Nanocrystals technologies have been introduced as advantageous, universal formulation approaches for the BCS class II and IV drugs. Nanocrystals, with greater surface to volume ratio, can effectively increase both the dissolution rate and saturation solubility of active ingredients The Nanocrystals is suitable drug delivery system for all commonly used routes of administration such as oral, IV, SC, and IM and topical application. Nanocrystals can also be incorporated into the tablets, capsules, fast-melts and lyophilized for sterile product applications. There are no of techniques which are used for production including precipitation, milling, high pressure homogenization and combination methods such as Nano-Edge, SmartCrystal and Precipitation-lyophilization-homogenization (PLH) technology
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