Using Pairwise Occurrence Information to Improve Knowledge Graph Completion on Large-Scale Datasets

Bilinear models such as DistMult and ComplEx are effective methods for knowledge graph (KG) completion. However, they require large batch sizes, which becomes a performance bottleneck when training on large scale datasets due to memory constraints. In this paper we use occurrences of entity-relation pairs in the dataset to construct a joint learning model and to increase the quality of sampled negatives during training. We show on three standard datasets that when these two techniques are combined, they give a significant improvement in performance, especially when the batch size and the number of generated negative examples are low relative to the size of the dataset. We then apply our techniques to a dataset containing 2 million entities and demonstrate that our model outperforms the baseline by 2.8% absolute on [email protected]: 8 pages, 3 figures, accepted at EMNLP 201

Ossifying tendinitis of the rotator cuff after arthroscopic excision of calcium deposits: report of two cases and literature review

Ossifying tendinitis (OT) is a type of heterotopic ossification, characterized by deposition of hydroxyapatite crystals in a histologic pattern of mature lamellar bone. It is usually associated with surgical intervention or trauma and is more commonly seen in Achilles or distal biceps tendons, and also in the gluteus maximus tendon. To our knowledge, there is no description of OT as a complication of calcifying tendinitis of the rotator cuff. In this report, we describe two cases in which the patients developed an OT of the supraspinatus after arthroscopic removal of calcium deposits. The related literature is reviewed

Ultrafast Laser Ablation, Intrinsic Threshold, and Nanopatterning of Monolayer Molybdenum Disulfide

Laser direct writing is an attractive method for patterning 2D materials without contamination. Literature shows that the femtosecond ablation threshold of graphene across substrates varies by an order of magnitude. Some attribute it to the thermal coupling to the substrates, but it remains by and large an open question. For the first time the effect of substrates on femtosecond ablation of 2D materials is studied using MoS$_{2}$ as an example. We show unambiguously that femtosecond ablation of MoS$_{2}$ is an adiabatic process with negligible heat transfer to the substrates. The observed threshold variation is due to the etalon effect which was not identified before for the laser ablation of 2D materials. Subsequently, an intrinsic ablation threshold is proposed as a true threshold parameter for 2D materials. Additionally, we demonstrate for the first time femtosecond laser patterning of monolayer MoS$_{2}$ with sub-micron resolution and mm/s speed. Moreover, engineered substrates are shown to enhance the ablation efficiency, enabling patterning with low-power femtosecond oscillators. Finally, a zero-thickness approximation is introduced to predict the field enhancement with simple analytical expressions. Our work clarifies the role of substrates on ablation and firmly establishes femtosecond laser ablation as a viable route to pattern 2D materials

Screening, Defects, and Dangling Bonds Induced Optical Damage Threshold in Monolayer MoS2

An optoelectronic device based on the TMDs should be versatile in its applications and be able to endure high optical intensities. In this thesis, I have shown the experimentally-measured damage threshold intensity range of 75 to 100 kW/cm2 of a monolayer MoS2 at room temperature. The corresponding photo-excited carrier density, for the CW photo-excitation, is ~1.6 x 10^10 cm^(-2). While the goal has been to find the damage threshold intensity, certain patterns that have emerged from the optical response of the monolayer MoS2 in the vicinity of the optical damage threshold needed to be thoroughly examined. I have quantified the experimental results and have attempted to qualitatively understand the underlying physics. The many-body effects play a crucial role in all these processes such that there is a complicated correlation. While explaining the physics through experimental results, I have attempted to disentangle the screening-related effects and damage and/or defect states related effects from the experimental dependencies, viz., optical power, laser irradiance time, and beam position. The measurements have been done by collecting the photoluminescence (PL) signals. The parameters such as excitonic peak amplitude, area, FWHM, and the central wavelength have been extracted from the curve fitting of the PL spectrums. In the optical power dependence measurement, I have compared the optical responses of the material by employing two different methods of measurement, viz., the Direct and Indirect PL measurement methods. In both these methods of measurement, I increase the excitation intensity step-wise but the method of collecting the PL signal differs. We will see that this slight difference in methodology provides us with a strikingly different optical response. In the laser irradiance time dependence measurement, I have exposed the sample continuously for 62 minutes in total. With this, the charge accumulation and resultant changes in the optical response of the material have been demonstrated. We will see that my experiments concretely debunk the claim of laser-induced atomic healing of defects. In the beam position dependent measurement, I deliberately create damage and optically scan the sample through pristine, within the damage, and at the damaged edge by collecting the PL signal from these locations. The characteristic enhancement in the PL signal is evidently found to be a real feature. From these measurements, salient features have been consistently observed such that these can be marked as the signatures of the damage incurrence. Signatures such as 2x to 4x times the increment in the peak amplitude, a similar increment in the area, changes in PL efficiency, 30% to 50% shrinkage in the FWHM, and 4 nm to 15 nm of a spectral blue shift in the A exciton peak in the PL spectrum. In this thesis, I will further demonstrate that all these reversible and irreversible changes are from the contributions of the screening effects such as Bandgap Renormalization (BGR) and Coulomb screening, defects and dangling bonds induced damage threshold in the monolayer MoS2

Shoulder arthroplasty in alkaptonuric arthropathy: A clinical case report and literature review

Alkaptonuria is a rare hereditary metabolic disease of autosomal recessive inheritance, resulting from deficiency of the enzyme homogentisic acid oxidase. The term ''alkaptonuria'' was first used in 1859 by Boedeker to describe a patient's urinary reducing compound, and in 1866, Virchow coined the term ''ochronosis'' due to typical yellow pigmentation. Deposition of this pigment in articular cartilage leads to ochronotic arthropathy, the most incapacitating complication of alkaptonuria. We report a rare case of shoulder ochronotic arthritis, treated with total shoulder arthroplasty, achieving a successful long-term clinical and radiological outcomes. \ua9 2012 Springer-Verlag

Role of defects and phonons in bandgap dynamics of monolayer WS2 at high carrier densities

We conduct ultrafast pump-probe spectroscopy in monolayer WS2 at high pump fluences to gain direct insight into interactions between a high density of carriers, defects, and phonons. We find that defects in the lattice play a major role in determining the relaxation dynamics by trapping the photoexcited carriers and acting as non-radiative recombination centers that emit phonons. In the high carrier density regime explored in our experiments, we observe substantial changes in the transient absorbance signal at unexpectedly long-time delays which we attribute to phonon-induced band gap modification. Our probe frequency dependent measurements and modeling indicate a renormalization of the bandgap by up to 23 meV. These results highlight the importance of defects and phonons for optical applications of monolayer transition metal dichalcogenides.Air Force Office of Scientific ResearchOpen access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]