A sufficient condition for the existence of an anti-directed 2-factor in a directed graph

Let D be a directed graph with vertex set V and order n. An anti-directed hamiltonian cycle H in D is a hamiltonian cycle in the graph underlying D such that no pair of consecutive arcs in H form a directed path in D. An anti-directed 2-factor in D is a vertex-disjoint collection of anti-directed cycles in D that span V. It was proved in [3] that if the indegree and the outdegree of each vertex of D is greater than (9/16)n then D contains an anti-directed hamilton cycle. In this paper we prove that given a directed graph D, the problem of determining whether D has an anti-directed 2-factor is NP-complete, and we use a proof technique similar to the one used in [3] to prove that if the indegree and the outdegree of each vertex of D is greater than (24/46)n then D contains an anti-directed 2-factor

Advanced Strategies for the Regeneration of Lumbar Disc Annulus Fibrosus.

Damage to the annulus fibrosus (AF), the outer region of the intervertebral disc (IVD), results in an undesirable condition that may accelerate IVD degeneration causing low back pain. Despite intense research interest, attempts to regenerate the IVD have failed so far and no effective strategy has translated into a successful clinical outcome. Of particular significance, the failure of strategies to repair the AF has been a major drawback in the regeneration of IVD and nucleus replacement. It is unlikely to secure regenerative mediators (cells, genes, and biomolecules) and artificial nucleus materials after injection with an unsealed AF, as IVD is exposed to significant load and large deformation during daily activities. The AF defects strongly change the mechanical properties of the IVD and activate catabolic routes that are responsible for accelerating IVD degeneration. Therefore, there is a strong need to develop effective therapeutic strategies to prevent or reconstruct AF damage to support operational IVD regenerative strategies and nucleus replacement. By the way of this review, repair and regenerative strategies for AF reconstruction, their current status, challenges ahead, and future outlooks were discussed

Comparison of CHIEF and Burton-Miller approaches in collocation Partition of Unity BEM for Helmholtz problems

Use of plane wave basis for the numerical solutions of acoustic wave problems using element based methods has become an attractive approach for extending the allowable frequency range for simulations beyond that available using piecewise polynomial elements. The non-uniqueness of the solution at characteristic frequencies resulting from the use of the conventional boundary integral equation is well known. The standard methods of overcoming this problem are the so-called CHIEF method and that of Burton and Miller. The latter method introduces a hypersingular integral which can be treated in several ways. In this paper we present results for Partition of Unity BEM (PUBEM) for Helmholtz problem and compare the performance of CHIEF against a Burton-Miller formulation regularised using the approach of Chen et al

Elastic fibers: The missing key to improve engineering concepts for reconstruction of the Nucleus Pulposus in the intervertebral disc.

The increasing prevalence of low back pain has imposed a heavy economic burden on global healthcare systems. Intense research activities have been performed for the regeneration of the Nucleus Pulposus (NP) of the IVD; however, tissue-engineered scaffolds have failed to capture the multi-scale structural hierarchy of the native tissue. The current study revealed for the first time, that elastic fibers form a network across the NP consisting of straight and thick parallel fibers that were interconnected by wavy fine fibers and strands. Both straight fibers and twisted strands were regularly merged or branched to form a fine elastic network across the NP. As a key structural feature, ultrathin (53 ± 7 nm), thin (215 ± 20 nm), and thick (890 ± 12 nm) elastic fibers were observed in the NP. While our quantitative analysis for measurement of the thickness of elastic fibers revealed no significant differences (p < 0.633), the preferential orientation of fibers was found to be significantly different (p < 0.001) across the NP. The distribution of orientation for the elastic fibers in the NP represented one major organized angle of orientation except for the central NP. We found that the distribution of elastic fibers in the central NP was different from those located in the peripheral regions representing two symmetrically organized major peaks (±45⁰). No significant differences in the maximum fiber count at the major angles of orientation (±45⁰) were observed for both peripheral (p = 0.427) and central NP (p = 0.788). Based on these new findings a structural model for the elastic fibers in the NP was proposed. The geometrical presentation, along with the distribution of elastic fibers orientation, resulting from the present study identifies the ultrastructural organization of elastic fibers in the NP important towards understanding their mechanical role which is still under investigation. Given the results of this new geometrical analysis, more-accurate multiscale finite element models can now be developed, which will provide new insights into the mechanobiology of the IVD. In addition, the results of this study can potentially be used for the fabrication of bio-inspired tissue-engineered scaffolds and IVD models to truly capture the multi-scale structural hierarchy of IVDs. STATEMENT OF SIGNIFICANCE: Visualization of elastic fibers in the nucleus of the intervertebral disk under high magnification was not reported before. The present research utilized extracellular matrix partial digestion to address significant gaps in understanding of nucleus microstructure that can potentially be used for the fabrication of bio-inspired tissue-engineered scaffolds and disk models to truly capture the multi-scale structural hierarchy of discs

A comparison of techniques for overcoming non-uniqueness of boundary integral equations for the collocation partition of unity method in two dimensional acoustic scattering

The Partition of Unity Method has become an attractive approach for extending the allowable frequency range for wave simulations beyond that available using piecewise polynomial elements. The non-uniqueness of solution obtained from the conventional boundary integral equation (CBIE) is well known. The CBIE derived through Green's identities suffers from a problem of non-uniqueness at certain characteristic frequencies. Two of the standard methods of overcoming this problem are the so-called Combined Helmholtz Integral Equation Formulation (CHIEF) method and that of Burton and Miller. The latter method introduces a hypersingular integral, which may be treated in various ways. In this paper, we present the collocation partition of unity boundary element method (PUBEM) for the Helmholtz problem and compare the performance of CHIEF against a Burton–Miller formulation regularised using the approach of Li and Huang

Zero-shot Video Moment Retrieval With Off-the-Shelf Models

For the majority of the machine learning community, the expensive nature of collecting high-quality human-annotated data and the inability to efficiently finetune very large state-of-the-art pretrained models on limited compute are major bottlenecks for building models for new tasks. We propose a zero-shot simple approach for one such task, Video Moment Retrieval (VMR), that does not perform any additional finetuning and simply repurposes off-the-shelf models trained on other tasks. Our three-step approach consists of moment proposal, moment-query matching and postprocessing, all using only off-the-shelf models. On the QVHighlights benchmark for VMR, we vastly improve performance of previous zero-shot approaches by at least 2.5x on all metrics and reduce the gap between zero-shot and state-of-the-art supervised by over 74%. Further, we also show that our zero-shot approach beats non-pretrained supervised models on the Recall metrics and comes very close on mAP metrics; and that it also performs better than the best pretrained supervised model on shorter moments. Finally, we ablate and analyze our results and propose interesting future directions.Comment: Accepted to the NeurIPS 2022 Workshop on Transfer Learning for NLP (TL4NLP). 12 pages, 5 figure

Effectiveness of distributed form of constraint induced movement therapy to improve functional outcome in chronic hemiparesis patients

Background:Upper limb hemiparesis is among the most common deficits after stroke that leads to disability. Learned nonuse develops due to over-reliance on the less affected limb for the functional activities. However for many stroke patients, participation in a traditional, more intense CIMT may be problematic, given the required practice intensity and the duration of the restraint schedule. So it is necessary to evaluate the effects of distributed form of Constraint Induced Movement Therapy (dCIMT) in improving functional outcome and quality of life in patients with chronic hemiparesis.Methods:36 hemiplegic patients following stroke were included. The experimental group was given dCIMT for 5sessions/week for 4 consecutive weeks in addition to conventional therapy while the control group received only conventional therapy. The outcome measures were motor activity log, wolf motor functional test and nine hole peg test.Results:The results of within group analysis for both the experimental group (Group-A) and control group B showed highly significant improvement on all the 3 outcome measures with P <0.0001.But the difference in the improvement of group-A compared to group-B was highly significant on the MAL and NHPT (P <0.0001) whereas it was not significant for WMFT performance score but highly significant for WMFT duration (U=23).Conclusion:dCIMT is an effective measure in improving the upper extremity motor function in terms of the quality and amount of use & speed and co- ordination. Thus improves the functional level and the quality of life of the patients with chronic stroke.

Complete Security Package for USB Thumb Drive

This paper is devoted to design and implement a complete security platform for USB flash disks due to the popularity of this device in exchanging data, it is a complete system security solution as it concerns the thumb drive due to the manipulation of I/O operation not the file system.  USB flash disks have been the major threat for computer system beside the internet threats where viruses can spread from computer to computer or from computer to network. USB complete security system presented by this paper is composed of three essential elements: kernel filter driver which will be installed in USB device driver stack to intercept all exchanged packets and send it to encryption unit, kernel level encryption/decryption unit and configuration unit. In contrary to most USB security modules the system presented by this paper will store only the round number of the key generator with the encrypted data. Round number will be coded using MD5 algorithm to increase the immunity of attacking data stored in the flash disks. Keywords: USB protection, kernel driver, device stack, encryption/decryption, filter driver, MD5.