2,092 research outputs found

    Searching for Extra Dimensions in the Early Universe

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    We investigate extra spatial dimensions (D=3+Ï”D = 3+\epsilon) in the early universe using very high resolution molecular rotational spectroscopic data derived from a large molecular cloud containing moderately cold carbon monoxide gas at Z ≈6.42\approx 6.42. It turns out that the Ï”\epsilon-dependent quantum mechanical wavelength transitions are solvable for a linear molecule and we present the solution here. The CO microwave data allows a very precise determination of =−0.00000657±.10003032 = -0.00000657 \pm .10003032. The probability that ≠0 \neq 0 is one in 7794, only 850 million years (using the standard cosmology) after the Big Bang.Comment: 17 pages, 2 figure

    The Parallel Persistent Memory Model

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    We consider a parallel computational model that consists of PP processors, each with a fast local ephemeral memory of limited size, and sharing a large persistent memory. The model allows for each processor to fault with bounded probability, and possibly restart. On faulting all processor state and local ephemeral memory are lost, but the persistent memory remains. This model is motivated by upcoming non-volatile memories that are as fast as existing random access memory, are accessible at the granularity of cache lines, and have the capability of surviving power outages. It is further motivated by the observation that in large parallel systems, failure of processors and their caches is not unusual. Within the model we develop a framework for developing locality efficient parallel algorithms that are resilient to failures. There are several challenges, including the need to recover from failures, the desire to do this in an asynchronous setting (i.e., not blocking other processors when one fails), and the need for synchronization primitives that are robust to failures. We describe approaches to solve these challenges based on breaking computations into what we call capsules, which have certain properties, and developing a work-stealing scheduler that functions properly within the context of failures. The scheduler guarantees a time bound of O(W/PA+D(P/PA)⌈log⁥1/fW⌉)O(W/P_A + D(P/P_A) \lceil\log_{1/f} W\rceil) in expectation, where WW and DD are the work and depth of the computation (in the absence of failures), PAP_A is the average number of processors available during the computation, and f≀1/2f \le 1/2 is the probability that a capsule fails. Within the model and using the proposed methods, we develop efficient algorithms for parallel sorting and other primitives.Comment: This paper is the full version of a paper at SPAA 2018 with the same nam

    Physical and Antibacterial Properties of Peppermint Essential Oil Loaded Poly (Δ-caprolactone) (PCL) Electrospun Fiber Mats for Wound Healing

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    The aim of this study was to fabricate and characterize various concentrations of peppermint essential oil (PEP) loaded on poly(Δ-caprolactone) (PCL) electrospun fiber mats for healing applications, where PEP was intended to impart antibacterial activity to the fibers. SEM images illustrated that the morphology of all electrospun fiber mats was smooth, uniform, and bead-free. The average fiber diameter was reduced by the addition of PEP from 1.6 ± 0.1 to 1.0 ± 0.2 Όm. Functional groups of the fibers were determined by Raman spectroscopy. Gas chromatography-mass spectroscopy (GC-MS) analysis demonstrated the actual PEP content in the samples. In vitro degradation was determined by measuring weight loss and their morphology change, showing that the electrospun fibers slightly degraded by the addition of PEP. The wettability of PCL and PEP loaded electrospun fiber mats was measured by determining contact angle and it was shown that wettability increased with the incorporation of PEP. The antimicrobial activity results revealed that PEP loaded PCL electrospun fiber mats exhibited inhibition against Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative) bacteria. In addition, an in-vitro cell viability assay using normal human dermal fibroblast (NHDF) cells revealed improved cell viability on PCL, PCLPEP1.5, PCLPEP3, and PCLGEL6 electrospun fiber mats compared to the control (CNT) after 48 h cell culture. Our findings showed for the first time PEP loaded PCL electrospun fiber mats with antibiotic-free antibacterial activity as promising candidates for wound healing applications

    Evaluation of Electrospun Poly(Δ-Caprolactone)/Gelatin Nanofiber Mats Containing Clove Essential Oil for Antibacterial Wound Dressing

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    The objective of this study was to produce antibacterial poly(Δ-caprolactone) (PCL)-gelatin (GEL) electrospun nanofiber mats containing clove essential oil (CLV) using glacial acetic acid (GAA) as a “benign” (non-toxic) solvent. The addition of CLV increased the fiber diameter from 241 ± 96 to 305 ± 82 nm. Aside from this, the wettability of PCL-GEL nanofiber mats was increased by the addition of CLV. Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the presence of CLV, and the actual content of CLV was determined by gas chromatography–mass spectrometry (GC-MS). Our investigations showed that CLV-loaded PCL-GEL nanofiber mats did not have cytotoxic effects on normal human dermal fibroblast (NHDF) cells. On the other hand, the fibers exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli. Consequently, PCL-GEL/CLV nanofiber mats are potential candidates for antibiotic-free wound healing applications

    Exponential Distribution of Locomotion Activity in Cell Cultures

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    In vitro velocities of several cell types have been measured using computer controlled video microscopy, which allowed to record the cells' trajectories over several days. On the basis of our large data sets we show that the locomotion activity displays a universal exponential distribution. Thus, motion resulting from complex cellular processes can be well described by an unexpected, but very simple distribution function. A simple phenomenological model based on the interaction of various cellular processes and finite ATP production rate is proposed to explain these experimental results.Comment: 4 pages, 3 figure
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