Linear Cut Research Articles

Distinguishing butchery cut marks from crocodile bite marks through machine learning methods

All models of evolution of human behaviour depend on the correct identification and interpretation of bone surface modifications (BSM) on archaeofaunal assemblages. Crucial evolutionary features, such as the origin of stone tool use, meat-eating, food-sharing, cooperation and sociality can only be addressed through confident identification and interpretation of BSM, and more specifically, cut marks. Recently, it has been argued that linear marks with the same properties as cut marks can be created by crocodiles, thereby questioning whether secure cut mark identifications can be made in the Early Pleistocene fossil record. Powerful classification methods based on multivariate statistics and machine learning (ML) algorithms have previously successfully discriminated cut marks from most other potentially confounding BSM. However, crocodile-made marks were marginal to or played no role in these comparative analyses. Here, for the first time, we apply state-of-the-art ML methods on crocodile linear BSM and experimental butchery cut marks, showing that the combination of multivariate taphonomy and ML methods provides accurate identification of BSM, including cut and crocodile bite marks. This enables empirically-supported hominin behavioural modelling, provided that these methods are applied to fossil assemblages.

The Generation Rate of Respirable Dust from Cutting Fiber Cement Siding Using Different Tools.

This article describes the evaluation of the generation rate of respirable dust (GAPS, defined as the mass of respirable dust generated per unit linear length cut) from cutting fiber cement siding using different tools in a laboratory testing system. We used an aerodynamic particle sizer spectrometer (APS) to continuously monitor the real-time size distributions of the dust throughout cutting tests when using a variety of tools, and calculated the generation rate of respirable dust for each testing condition using the size distribution data. The test result verifies that power shears provided an almost dust-free operation with a GAPS of 0.006 g m-1 at the testing condition. For the same power saws, the cuts using saw blades with more teeth generated more respirable dusts. Using the same blade for all four miter saws tested in this study, a positive linear correlation was found between the saws' blade rotating speed and its dust generation rate. In addition, a circular saw running at the highest blade rotating speed of 9068 rpm generated the greatest amount of dust. All the miter saws generated less dust in the 'chopping mode' than in the 'chopping and sliding' mode. For the tested saws, GAPS consistently decreased with the increases of the saw cutting feed rate and the number of board in the stack. All the test results point out that fewer cutting interactions between the saw blade's teeth and the siding board for a unit linear length of cut tend to result in a lower generation rate of respirable dust. These results may help guide optimal operation in practice and future tool development aimed at minimizing dust generation while producing a satisfactory cut.

Laparoscopic Management of Interstitial Ectopic Using Simple and Safe Technique: Case Series and Review of Literature.

To determine the safety and sustainability of operative laparoscopy in surgical management of cornual and interstitial ectopic pregnancy using a simple and practical method. Case series of five consecutive cases. Endoscopy unit in Alexandria University Hospital and Alexandria New Medical Center. Between July 2013 and May 2015, five women with interstitial and cornual ectopic pregnancies were admitted for laparoscopic surgical treatment. Full medical and surgical histories were taken. We explained all alternatives for both partners before informed. Patients underwent laparoscopy for management of the corneal ectopic. All surgeries were done by the same surgeon (T.S.) with different assistants. We gave different uterotonics drugs to devascularize the uterus. Two or more devascularization sutures were done on each end of the corneal ectopic. We used monopolar and bipolar electrocoagulation when indicated. We did linear cut of the interstitial ectopic with evacuation of the fetus and placental tissues. Extraction of the conceptus was performed through 10mm port. Follow-up of the beta-hCG was done weekly till negative results were obtained. The devascularization sutures together with uterotonics make the surgical treatment of interstitial ectopic easy and safe. This simple technique minimizes blood loss and decreases necrosis that follows excessive use of diathermy. This was demonstrated successfully in different types of interstitial ectopic. We did not remove any part of the uterus during surgery. Clinical criteria of the study cases were discussed. Type, size, blood loss and complications, and duration of the surgery were documented. Operative laparoscopy using sutures and uterotonics is safe and sustainable approach in treatment of interstitial ectopic pregnancy.

Optimal power flow of a distribution system based on increasingly tight cutting planes added to a second order cone relaxation

Convex relaxations of the optimal power flow (OPF) problem have received a lot of attention in the recent past. In this work, we focus on a second-order cone (SOC) relaxation applied to an OPF based on a branch flow model of a radial and balanced distribution system. We start by examining various sets of conditions ensuring the exactitude of such a relaxation, which is the main focus of the existing literature. In particular, we observe that these sets always include a requirement on the objective to be a minimization of a function increasing with the branch flow apparent powers. We consider this hypothesis to be at odds with what is to be expected of an active distribution system and demonstrate in specific case studies its counterproductive impact. We continue by introducing an objective function allowing distributed generations and storages (DGS) to take advantage of the benefits they bring to the power system as a whole. As this entails the possibility for the relaxation not to be exact, we describe and prove the theoretical convergence to optimality of an algorithm consisting in adding an increasingly tight linear cut to the SOC relaxation. In order to allow the attainment of a solution satisfying the network constraints in a finite number of steps, we continue by introducing a tailored termination criterion. Afterwards, we investigate the ability of our algorithm to obtain a satisfactory solution on several case studies, spanning various network sizes, number of nodes equipped with DGs and their level of penetration. We then conclude on the benefits brought about by this approach and reflect on its limits and the opportunities for further improvements.

Split cuts and extended formulations for Mixed Integer Conic Quadratic Programming

We study split cuts and extended formulations for Mixed Integer Conic Quadratic Programming (MICQP) and their relation to Conic Mixed Integer Rounding (CMIR) cuts. We show that CMIR is a linear split cut for the polyhedral portion of an extended formulation of a quadratic set and it can be weaker than the nonlinear split cut of the same quadratic set. However, we also show that families of CMIRs can be significantly stronger than the associated family of nonlinear split cuts.

GEOMETRY, PENETRATION FORCE, AND CUTTING PROFILE OF DIFFERENT 23-GAUGE TROCARS SYSTEMS FOR PARS PLANA VITRECTOMY

To investigate the geometry, penetration force, and cutting profile of 23-gauge trocar systems for pars plana vitrectomy based on their grinding methods in a standardized laboratory setting. In this experimental study, Eleven different commercially available 23-gauge sclerotomy trocar systems were divided into 4 groups according to their needle grinding and deburring: "back" bevel, "spear" bevel, "lancet" bevel, and "spatula" bevel. The normative geometrical data of the trocar systems were systematically analyzed according to nomenclature ISO 7864 and ISO 9626. Force to penetrate a 0.4-mm thick polyurethane foil was measured by a Penetrometer, when the trocar needle was piercing, cutting, and sliding through the foil at different defined loading phases and plotted as a load-displacement diagram. Magnified images of the consecutive cut were taken under a microscope after the entire penetration through the foil. Three physicians used all trocar systems in a masked fashion on human sclera to evaluate the manual penetration force in 30° and 90°. The mean outer diameter of the trocar systems was 0.630 ± 0.009 mm, and the mean outer diameter of the trocars was 0.750 ± 0.013 mm. The mean point length was 3.11 ± 0.49 mm, and the mean length of the bevel was 1.46 ± 0.23 mm. The primary bevel angle was 10.75 ± 0.41°, and the secondary bevel angle was 65.9 ± 42.56°. The piercing forces of the back bevel and spear-pointed trocars/needles were at the same level (0.087 ± 0.028 N). The lancet-pointed needle had remarkable low piercing and cutting forces with 0.41 N (range, 0.35-0.47 N). The spatula bevel tip showed the highest penetration piercing force with 1.6 N (range, 1.59-1.73 N). The back bevel systems induced frequently triangular-shaped incisions, with two nearly rectangular cuts of short length. The spear bevels produced a regular characteristic linear cut. Especially, the lancet blade created straight cut with a linear wound apposition. Spatula trocar systems caused usually an arched accurate incision. The manual force to penetrate the human sclera in an angled and rectangular angle appeared in the surgeons hand lower with a back bevel, lancet, or spear tip, whereas higher with spatula bevel systems. Lancet and back bevel systems show less penetration force of inner needles than the spatula systems. The results of the penetration force experiments correlated well with the manual force on sclera.

Simulation of dynamic crack propagation under quasi-static loading

It is known that, within the framework of linear fracture mechanics (LFM) under quasistatic loading, the mechanicalstress field in the vicinity of the tip of a symmetrically loaded crack represented by a mathe� matical linear cut is determined by stressintensity factor (SIF) KI for the first loading mode, the corre� sponding critical value of which is found experimen� tally. The criterion of the critical intensity factor widely used in engineering practice was extended in many works also to the dynamicfracture case (1, 2):

In vitro resistance of titanium and resorbable (poly l-co-dl lactic acid) osteosynthesis in mandibular body fracture

This study was a comparative evaluation of the bending resistance of metallic and resorbable plates and screws in a mandibular body fracture model. Forty polyurethane synthetic hemimandibles were used; a vertical linear cut was made between the second and first premolars. These 40 hemimandibles were divided into four groups of 10 and were fixed with titanium plates and screws or resorbable plates and screws, with monocortical screws in the upper sector and bicortical screws in the lower sector. Bending resistance tests were done on a universal testing machine with a linear displacement speed of 1mm/min, a cell load of 500N, and a load cell on the lower central incisor or on the lower second premolar. Results were analyzed using the Student's t-test, with the significance level set at 5%. No statistically significant differences were observed between the groups studied, either in the analysis of the osteosynthesis materials or related to the load-bearing points. The variables of displacement and peak load did not present any significant differences. In this in vitro model of a mandibular body fracture, the mechanical behaviour of a resorbable osteosynthesis was similar to that of a titanium osteosynthesis.

Shadow price based genetic algorithms for the cutting stock problem

The Cutting Stock Problem (CSP) is an integer combinatorial optimisation problem (an NP hard problem). It is an important problem in many industrial applications. In recent years, various traditional algorithms have been applied to the CSP, such as the Linear Programming (LP), the Branch and Cut (BC), the Evolutionary Algorithm (EA), etc. To continue improve performance, this paper proposes a novel Shadow Price based Genetic Algorithm (SPGA) to solve the CSP. The main contribution of this work is to combine distinct methods to generate better solutions. The experimental results have shown that the new SPGA has produced much better solutions than the classic Genetic Algorithm (GA) and other bio-inspired algorithms. This paper also demonstrates the new algorithm's capability of solving multi-objective optimisation problems.

Scatter search for the cutwidth minimization problem

The cutwidth minimization problem consists of finding a linear layout of a graph so that the maximum linear cut of edges is minimized. This NP-hard problem has applications in network scheduling, automatic graph drawing and information retrieval. We propose a heuristic method based on the Scatter Search (SS) methodology for finding approximate solutions to this optimization problem. This metaheuristic explores solution space by evolving a set of reference points. Our SS method is based on a GRASP constructive algorithm, a local search strategy based on insertion moves and voting-based combination methods. We also introduce a new measure to control the diversity in the search process. Empirical results with 252 previously reported instances indicate that the proposed procedure compares favorably to previous metaheuristics for this problem, such as Simulated Annealing and Evolutionary Path Relinking.

Traumatic Atrial Septal Defect and Coronary Sinus to Left Atrium Fistula from Coronary Sinus Pacing Lead Removal

Traumatic Atrial Septal Defect and Coronary Sinus to Left Atrium Fistula from Coronary Sinus Pacing Lead Removal

Bilateral Complicated Stromal Dissections During Mechanical Epikeratome Separation of the Corneal Epithelium

To present a case of bilateral inadvertent stromal cuts during mechanical epikeratome separation of the corneal epithelium using a Centurion SES epikeratome (Norwood EyeCare Pty Ltd). A 25-year-old woman underwent epi-LASIK surgery. Preoperative examinations showed no remarkable findings. After epithelial flap creation, a linear stromal cut near the temporal upper flap edge was found in the right eye. An irregular stromal cut involving the central cornea was found in the left eye after undergoing epi-LASIK with a new separator. Excimer laser ablation was continued in both eyes without flap reposition. Six months postoperatively, best spectacle-corrected visual acuity was 20/20 in the right eye and 20/25 in the left eye. Corneal topographic examination revealed a regular pattern in the right eye and irregularities in the left. Stromal dissection during mechanical separation of the corneal epithelium with a Centurion SES epikeratome is a potential complication of epi-LASIK. Visual impairment can result from such complications.

The numerical solution of boundary-value problems for an elastic body with an elliptic hole and linear cracks

Using the boundary-element method which is a combination of a fictitious load and a displacement discontinuity, numerical solutions are obtained for two-dimensional (plane deformation) boundary-value problems for the elastic equilibrium of infinite and finite homogeneous isotropic bodies having elliptic holes with cracks and cuts of finite length. Using the method of separation of variables, the boundary-value problem is solved in the case of an infinite domain containing an elliptic hole with a linear cut on whose contour the symmetry conditions are fulfilled.

An in vitro study of femtosecond laser photodisruption in rabbit sclera

To explore the possibility of photodisruption in rabbit sclera by femtosecond (fs) laser and seek appropriate incision techniques and relevant parameters, a fs laser (800 nm/50 fs) with different pulse energies was applied to irradiate rabbit sclera in vitro. By moving a computer-controlled three-axis translation stage to which the sample was attached, the laser achieved three types of incisions: transscleral channel, snake pattern and linear cut. The irradiated samples were observed by light microscopy and scanning electron microscopy (SEM). In comparison with fs laser, Nd:YAG was used as control. The experimental results show that through an objective lens with numerical aperture (NA) of 0.2, the fs laser with power intensity larger than 955 TW/cm2 and pulse energy ranging from 37.5–125 μJ, cutting depths from 30–70 μm may be achieved after linearly scanning in sclera at a translation speed of 0.1 mm/s. However, it failed to make any photodisruption when the power intensity was below 796 TW/cm2 or the pulse energy was less than 31.25 μJ under the same condition. Compared with the Nd:YAG laser, the inner wall of the channel was smoother and the damage to the surrounding tissues was slight with the fs laser. The high precision of intrascleral photodisruption and minimal damage to surrounding tissues by a fs laser display its potential application in the treatment of glaucoma.

Magnetic helicity content in solar wind flux ropes

AbstractMagnetic helicity (H) is an ideal magnetohydrodynamical (MHD) invariant that quantifies the twist and linkage of magnetic field lines. In magnetofluids with low resistivity, H decays much less than the energy, and it is almost conserved during times shorter than the global diffusion timescale. The extended solar corona (i.e., the heliosphere) is one of the physical scenarios where H is expected to be conserved. The amount of H injected through the photospheric level can be reorganized in the corona, and finally ejected in flux ropes to the interplanetary medium. Thus, coronal mass ejections can appear as magnetic clouds (MCs), which are huge twisted flux tubes that transport large amounts of H through the solar wind. The content of H depends on the global configuration of the structure, then, one of the main difficulties to estimate it from single spacecraft in situ observations (one point - multiple times) is that a single spacecraft can only observe a linear (one dimensional) cut of the MC global structure. Another serious difficulty is the intrinsic mixing between its spatial shape and its time evolution that occurs during the observation period. However, using some simple assumptions supported by observations, the global shape of some MCs can be unveiled, and the associated H and magnetic fluxes (F) can be estimated. Different methods to quantify H and F from the analysis of in situ observations in MCs are presented in this review. Some of these methods consider a MC in expansion and going through possible magnetic reconnections with its environment. We conclude that H seems to be a ‘robust’ MHD quantity in MCs, in the sense that variations of H for a given MC deduced using different methods, are typically lower than changes of H when a different cloud is considered. Quantification of H and F lets us constrain models of coronal formation and ejection of flux ropes to the interplanetary medium, as well as of the dynamical evolution of MCs in the solar wind.

A Quantitative Assessment of the Outcome of the Doha Development Agenda

Different options contemplated by the negotiators of the Doha Development Agenda are assessed using the Computable General Equilibrium model MIRAGE, the MAcMap and GTAP databases, existing estimates of protection in the services sector as well as estimates of the administrative and transaction costs to be reduced by trade facilitation measures. In all scenarios (with the exception of trade), we consider that the G90 will not be requested to liberalise. Export subsidies in agriculture are completely eliminated, taking into account the 2013 deadline agreed in Hong Kong in December 2005, and domestic farm support is halved. When an average 36% linear cut in tariffs is implemented in the industrial and in the agricultural sectors (but with a reduction limited to 25% for sensitive products in the latter sector), we end up with a Round for nothing. At the opposite of the spectrum, free trade in goods would lead to USD 232 bn welfare gains for the world economy (expressed in 2005 terms). There is however more to be gained, for the world economy, from a 25% cut of the barriers in services, than from a 70% tariff cut in agriculture in the North and a 50% cut in the South. On the top of this, a successful trade facilitation agenda would be equivalent to doubling official development aid to Sub-Saharan Africa countries after 2020. In the latter case, how to finance such program remains however a challenging issue.

Ultrastructure of Femtosecond Laser trephination for keratoplasty

Abstract Purpose: Femtosecond Laser are proposed as tools for trephination in keratoplasty. This novel technology is used to realize complex tissue dissection profiles that may potentially allow a reduced astigmatism, enhanced wound stability and more selective transplantation of tissue parts. Methods: Using a 60kHz IntraLase Femtosecond Laser (IntraLase fs60, IntraLase Corp., CA) different trephination patterns were performed in ten porcine eyes. Corneoscleral specimen were subsequently cultured for five days before being processed for histological assessment. Corneal thickness before the procedure and after histological embedding was measured, the geometry of the dissection line was evaluated and the morphological characteristics of the cellular architecture along the lesion was analyzed at high magnification light microscopy. Results: Straight and bevelled trephinations were realized with equal technical ease after applanation of the corneal curvature. The focus pattern lines within the corneal stroma presented as straight lines of 5+/‐10 μm crossing the histoarchitecture of the collagen lamellae without deflection within of the corneal stroma. Sporadic hematoxylin‐eosin negative spots were suggestive of cellular debris altered by the laser spots. Cell nuclei were also found scattered within the dissection line. Conclusions: Tissue dissection for corneal grafting in complex bevelled patterns proved feasible with the IntraLase‐Device. Separation of corneal collagen lamellae occurred along the targeted line, leaving a linear cut without visible ablation of tissue nor discernable collateral damage to the surrounding tissue. The smoothness of the cut may allow, in clinical application, novel selective tissue transplantation, potentially minimizing interface haze.

An economic model for credit assessment problems using screening approaches

How to combine varying credit information collected from various sources at difference periods for the purpose of credit assessment is an important issue for some financial companies. In this article, the screening procedures using individual cut and linear cut approaches are proposed to solve the issue and to control default rates in credit assessment problems. Then, an economic screening model is provided to incorporate with the proposed approaches so that optimal cutoff points are determined by maximizing total profit. An example of a loan programme is illustrated the use of the proposed economic screening procedures. The results show that the linear cut approach uniformly outperforms the individual cut approach in terms of total profit and computation complexity. Moreover, the linear cut approach can be easily extended to the case with multiple variables and the solution is also in a closed form. Therefore, the screening procedure using the linear cut approach is strongly recommended for credit assessment problems.

Spatial persistence of fluctuating interfaces.

We show that the probability, P0(l), that the height of a fluctuating (d+1)-dimensional interface in its steady state stays above its initial value up to a distance l, along any linear cut in the d-dimensional space, decays as P0(l) approximately l(theta). Here straight theta is a "spatial" persistence exponent, and takes different values, straight theta(s) or straight theta(0), depending on how the point from which l is measured is specified. These exponents are shown to map onto corresponding temporal persistence exponents for a generalized d = 1 random-walk equation. The exponent straight theta(0) is nontrivial even for Gaussian interfaces.

Gas Dynamic Effects on Laser Cut Quality

The presence of a gas jet plays an important role in laser cutting. Both the cutting efficiency and cut quality are very sensitive to gas pressure and nozzle standoff distance because of the complex nature of shock fronts and associated phenomena in a supersonic gas jet impinging on a workpiece. An idealized case is considered first, where the cut is assumed to be a circular hole directly underneath and concentric with the gas jet nozzle. A more realistic case of an axisymmetric nozzle impinging on a plate with a linear cut is considered next. Unlike the idealized case, the problem now is three-dimensional. Simple experiments to measure the through-kerf mass flow rate were carried out for both geometries. The two important forces exerted by the gas jet for melt ejection, namely, shear force and pressure gradient, show the same trend as that of the mass flow rate with varying gas pressure and standoff. The mass flow rate for the three-dimensional case shows the same behavior as that of the axisymmetric case, indicating the basic shock structures of the axisymmetric case are applicable to the real cutting cases. Laser cutting of mild steels under the corresponding conditions was performed, and the cut quality characterized by roughness, dross attachment, and recast layer thickness was analyzed. The deterioration of cut quality with the gas pressure and standoff is found to closely match reductions in through-kerf mass flow rate. It is thus verified that the shock structure of the gas jet and the associated mass flow rate have a direct impact on laser cutting as predicted.