Context-Free Path Queries on RDF Graphs

Navigational graph queries are an important class of queries that canextract implicit binary relations over the nodes of input graphs. Most of the navigational query languages used in the RDF community, e.g. property paths in W3C SPARQL 1.1 and nested regular expressions in nSPARQL, are based on the regular expressions. It is known that regular expressions have limited expressivity; for instance, some natural queries, like same generation-queries, are not expressible with regular expressions. To overcome this limitation, in this paper, we present cfSPARQL, an extension of SPARQL query language equipped with context-free grammars. The cfSPARQL language is strictly more expressive than property paths and nested expressions. The additional expressivity can be used for modelling graph similarities, graph summarization and ontology alignment. Despite the increasing expressivity, we show that cfSPARQL still enjoys a low computational complexity and can be evaluated efficiently.Comment: 25 page

A simulation study of the deflection of the slab and at subgrade by a high-speed train

As the demand for rapid transport and higher frequency rail services around the world is increasing, greater stresses are induced on the track, thus the necessity for a sustainable and durable railway structure is essential. To meet these demands it is seen that slab track construction is generally preferred for High-Speed Railways (HSR) as opposed to the conventional ballasted track as the slab track can sustain higher dynamic loading with less maintenance. In line with this research, a study on the development and application of a 3D structural model using ABAQUS software is carried out to evaluate the dynamic behaviour of HSR slab track. This research aims at evaluating the continuously fastened Balfour Beatty Embedded Rail Track System (ERS) and comparing it with the RHEDA (RTS) slab track system, which is discreetly fastened. The modelled rail tracks consist of a rail fastened onto a slab laid on a suitable foundation. The foundation consists of a Subbase Layer (HBL) placed on a Capping Layer (FPL) overlaying the subgrade soil. This thesis looks at the findings of dynamic analysis of various parameters which are affected during the high-speed passage of trains. Constant speeds are applied to a moving load as a part of dynamic analysis. Parametric studies are performed for CBL stiffness, soil stiffness and CBL thickness. The motion speeds are also changed to see its effect on the rail track. This study will shed light on the dynamic behaviour of ETS and RTS with changing parameters

Science Teaching Efficacy Beliefs of Palestinian Elementary Education Students

To assess elementary education students’ self-efficacy beliefs in science teaching, the Science Teaching Efficacy Belief Instrument developed by Enochs and Riggs was used. The instrument consisted of two scales, Personal Science Teaching Efficacy Belief Scale and the Outcome Expectancy Scale. It was administered to 90 undergraduate university students majoring in elementary education at a large public Palestinian university. Results indicated that students’ self-efficacy beliefs in science teaching were comparable to those reported in the original study by Enochs and Riggs. Overall, the participants presented moderate to high self-efficacy in science teaching

Millimeter Wave Communications

Millimeter wave (mmWave) technologies promise to revolutionize wireless networks by enabling multi-gigabit data rates. However, they suffer from high attenuation, and hence have to use highly directional antennas to focus their power on the receiver. Existing radios have to scan the space to find the best alignment between the transmitter’s and receiver’s beams, a process that takes up to a few seconds. This delay is problematic in a network setting where the base station needs to quickly switch between users and accommodate mobile clients. We present Agile-Link, the first mmWave beam steering system that is demonstrated to find the correct beam alignment without scanning the space. Instead of scanning, Agile- Link hashes the beam directions using a few carefully chosen hash functions. It then identifies the correct alignment by tracking how the energy changes across different hash functions. Our results show that Agile-Link reduces beam steering delay by orders of magnitude.National Science Foundation (U.S.

Effects of Adjustments to Wheelchair Seat to Back Support Angle on Head, Neck, and Shoulder Postures

Background: People spend a long time in the sitting position may have poor alignment that leads to neck and back pain. A wheelchair represents mobility for people with cerebral palsy, who are unable to walk. They spend long periods of time sitting in their wheelchair. Opining the seat to back support angle of the wheelchair enable realignment body segments and improves posture. Objective: 1) assessed the validity/reliability of Coach’s Eye (CE) smart device application, 2) examined the effect of seat to back support angle adjustments on head, neck, and shoulder posture in the sitting position, and 3) compared changes in cervical rotation at each seat to back support angle. Methods: Thirty-four subjects between the ages of 18 and 45 years abled subjects and subjects with cerebral palsy. All subjects sat in a research wheelchair with seat to back support angle at (90°, 100°, and 110°). Photographs were taken and analyzed by ImageJ and cache’s Eye (CE) software. Three body posture angles were used: sagittal head angle (SHA), cervical angle (CVA), and shoulder angle (SA). Results: There were highly significant differences on abled subjects for CVA and SA (p \u3c 0.001) among the three seat to back support angles. CE had high validity for all angles (r = 0.99, 0.98, 0.99 respectively, p \u3c 0.001). Inter-rater reliability for SHA, CVA, and SA among the three seat to back support angles was high (ICC ranged from 0.95 to 0.99). There were highly significant differences on abled subjects for CVA and SA (p \u3c 0.001). There were highly significant differences on subjects with cerebral palsy for SHA and CVA (p \u3c 0.001) among the three seat to back support angles. Conclusion: Head (CVA) and shoulder (SA) alignment was closest to neutral posture for abled subjects with seat to back support angles set at 110° and 90°, respectively. Head (SHA) and (CVA) alignment was closest to neutral posture for subjects with CP with seat to back support angles set at 110°

Epithelial-mesenchymal transitions: the importance of changing cell state in development and disease

The events that convert adherent epithelial cells into individual migratory cells that can invade the extracellular matrix are known collectively as epithelial-mesenchymal transition (EMT). Throughout evolution, the capacity of cells to switch between these two cellular states has been fundamental in the generation of complex body patterns. Here, we review the EMT events that build the embryo and further discuss two prototypical processes governed by EMT in amniotes: gastrulation and neural crest formation. Cells undergo EMT to migrate and colonize distant territories. Not surprisingly, this is also the mechanism used by cancer cells to disperse throughout the body

Relativistic spin-0 particle in a box: bound states, wavepackets, and the disappearance of the Klein paradox

The "particle in a box" problem is investigated for a relativistic particle obeying the Klein-Gordon equation. To find the bound states, the standard methods known from elementary non-relativistic quantum mechanics can only be employed for "shallow" wells. For deeper wells, when the confining potentials become supercritical, we show that a method based on a scattering expansion accounts for Klein tunneling (undamped propagation outside the well) and the Klein paradox (charge density increase inside the well). We will see that in the infinite well limit, the wavefunction outside the well vanishes and Klein tunneling is suppressed: quantization is thus recovered, similarly to the non-relativistic particle in a box. In addition, we show how wavepackets can be constructed semi-analytically from the scattering expansion, accounting for the dynamics of Klein tunneling in a physically intuitive wa

Assessing the exposure-response relationship of sleep disturbance and vibration in field and laboratory settings

Exposure to nocturnal freight train vibrations may impact sleep, but exposure-response relationships are lacking. The European project CargoVibes evaluated sleep disturbance both in the field and in the laboratory and provides unique data, as measures of response and exposure metrics are comparable. This paper therefore provides data on exposure-response relationships of vibration and sleep disturbance and compares the relationships evaluated in the laboratory and the field. Two field studies (one in Poland and one in the Netherlands) with 233 valid respondents in total, and three laboratory studies in Sweden with a total of 59 subjects over 350 person-nights were performed. The odds ratios (OR) of sleep disturbance were analyzed in relation to nighttime vibration exposure by ordinal logit regression, adjusting for moderating factors common for the studies. Outcome specific fractions were calculated for eleven sleep outcomes and supported comparability between the field and laboratory settings. Vibration exposure was significantly associated to sleep disturbance, OR = 3.51 (95% confidence interval 2.6–4.73) denoting a three and a half times increased odds of sleep disturbance with one unit increased 8 h nighttime log10 Root Mean Square vibration. The results suggest no significant difference between field and laboratory settings OR = 1.37 (0.59–3.19). However, odds of sleep disturbance were higher in the Netherlands as compared to Sweden, indicating unexplained differences between study populations or countries, possibly related to cultural and contextual differences and uncertainties in exposure assessments. Future studies should be carefully designed to record explanatory factors in the field and enhance ecological validity in the laboratory. Nevertheless, the presented combined data set provides a first set of exposure response relationships for vibration-induced sleep disturbance, which are useful when considering public health outcomes among exposed populations

Evolution of strictly localized states in non-interacting quantum field theories with background fields

We investigate the construction of spin-1/2 fermionic and spin-0 bosonic wave-packets having compact spatial support in the framework of a computational quantum field theory (QFT) scheme offering space-time solutions of the relativistic wave equations in background fields. In order to construct perfectly localized wave-packets, we introduce a spatial density operator accounting for particles of both positive and negative charge. We examine properties of the vacuum and single-particle expectation values of this operator and compare them to the standard QFT particle and anti-particle spatial densities. The formalism is illustrated by computing numerically the Klein tunneling dynamics of strictly localized wave-packets impinging on a supercritical electrostatic step. The density operator introduced here could be useful to model situations in which it is desirable to avoid dealing with the infinite spatial tails intrinsic to pure particle or anti-particle wave-packets

Exercise protects against obesity induced semen abnormalities via downregulating stem cell factor, upregulating Ghrelin and normalizing oxidative stress

Increased oxidative stress and hormonal imbalance have been hypothesized to underlie infertility in obese animals. However, recent evidence suggests that Ghrelin and Stem Cell Factor (SCF) play an important role in fertility, in lean individuals. Therefore, this study aimed at investigating whether changes in the levels of Ghrelin and SCF in rat testes underlie semen abnormal parameters observed in obese rats, and secondly, whether endurance exercise or Orlistat can protect against changes in Ghrelin, SCF, and/or semen parameters in diet induced obese rats. Obesity was modelled in male Wistar rats using High Fat Diet (HFD) 12-week protocol. Eight week-old rats (n=40) were divided into four groups, namely, Group I: fed with a standard diet (12 % of calories as fat); Group II: fed HFD (40 % of calories as fat); Group III: fed the HFD with a concomitant dose of Orlistat (200 mg/kg); and Group IV: fed the HFD and underwent 30 min daily swimming exercise. The model was validated by measuring the levels of testosterone, FSH, LH, estradiol, leptin, triglycerides, total, HDL, and LDL cholesterol, and final change in body weight. Levels were consistent with published obesity models (see Results). As predicted, the HFD group had a 76.8 % decrease in sperm count, 44.72 % decrease in sperm motility, as well as 47.09 % increase in abnormal sperm morphology. Unlike the control group, in the HFD group (i.e. obese rats) Ghrelin mRNA and protein were elevated, while SCF mRNA and protein were diminished in the testes. Furthermore, in the HFD group, SOD and GPx activities were significantly reduced, 48.5±5.8 % (P=0.0012) and 45.6±4.6 % (P=0.0019), respectively, while TBARS levels were significantly increased (112.7±8.9 %, P≤0.0001). Finally, endurance exercise training and Orlistat administration individually and differentially protected semen parameters in obese rats. The mechanism includes, but is not limited to, normalizing the levels of Ghrelin, SCF, SOD, GPx and TBARS. In rat testes, diet induced obesity down regulates SCF expression, upregulates Ghrelin expression, and deteriorate oxidative stress levels, which are collectively detrimental to semen parameters. Exercise, and to a lesse r extent Orlistat administration, protected effectively against this detrimental effect