Small Cuts Research Articles

Animal left–right asymmetry

Symmetry is appealing, be it in architecture, art or facial expression, where symmetry is a key feature to finding someone attractive or not. Yet, asymmetries are widespread in nature, not as an erroneous deviation from the norm but as a way to adapt to the prevailing environmental conditions at a time. Asymmetries in many cases are actively selected for: they might well have increased the evolutionary fitness of a species. Even many single-celled organisms are built asymmetrically, such as the pear-shaped ciliate Paramecium, which may depend on its asymmetry to navigate towards the oxygen-richer surface of turbid waters, at least based on modeling. Everybody knows the lobster with its asymmetric pair of claws, the large crusher usually on the left and the smaller cutter on the right. Snail shells coil asymmetrically, as do the organs they house. Organ asymmetries are found throughout the animal kingdom, referring to asymmetric positioning, asymmetric morphology or both, with the vertebrate heart being an example for the latter. Functional asymmetries, such as that of the human brain with its localization of the language center in one hemisphere, add to the complexity of organ asymmetries and presumably played a decisive role for sociocultural evolution. The evolutionary origin of organ asymmetries may have been a longer than body length gut, which allows efficient retrieval of nutrients, and the need to stow a long gut in the body cavity in an orderly manner that ensures optimal functioning. Vertebrate organ asymmetries (situs solitus) are quite sophisticated: in humans, the apex of the asymmetrically built heart points to the left; the lung in turn, due to space restrictions, has fewer lobes on the left than on the right side (two versus three in humans), stomach and spleen are found on the left, the liver on the right, and small and large intestine coil in a chiral manner (Figure 1A). In very rare cases (1:10,000), the organ situs is inverted (situs inversus), while heterotaxia refers to another rare situation (about 1:1,000), in which subsets of organs show normal or aberrant positioning or morphology (Figure 1B). Individuals with situs solitus or situs inversus are healthy, whereas heterotaxia presents severe congenital malformations. Many human syndromes are known in which patients suffer from laterality defects, such as Katagener syndrome, in which the organ situs is inverted in one half of patients and males are sterile. Snail shells and vertebrate organs are examples of biased asymmetries with on average only one inversion in every 10,000 cases. Other asymmetries such as the coiling of the tails of piglets occur randomly with a 50:50 distribution. This primer exclusively deals with organ asymmetries in the animal kingdom, specifically with the mechanisms that ensure the development of biased asymmetries during embryogenesis.

DISTRIBUTED VIDEO IDENTIFICATION WITH PERCEPTUAL TAGS IN PEER-TO-PEER NETWORKS

Existing methods in Peer-to-Peer (P2P) networks mainly use file tags or cryptographic hashes of the entire file for video searching and identification. These methods however become insufficient to correctly identify a video when the name and format of the files are changed. In this paper, a distributed solution is proposed for video identification and copy detection in P2P networks, which represents a video file in the network with a set of (64-256) bits, named as perceptual tags. As such information is derived from the perceptual content of the video rather than its bitstream representation as in the case of cryptographic hashes, it provides a robust identification after the alterations in the file names and formats provided that the visual quality of the video is at acceptable levels. The paper first briefly discusses the requirements for a distributed perceptual tagging system considering the low computational power and low bandwidth of internet users. Then, it presents the proposed perceptual tag extraction method using the temporal differences between the video frame averages and the proposed distributed searching scheme for a P2P implementation. The proposed extraction and searching methods provide robustness to the alterations in video formats and small additions and cuttings in the video content as the typical processing in P2P environment and also achieve uniform distribution and storage load between the peers.

Fruit-scarring BeetleMyochrous melancholicusJacobyas a Potential New Pest of Banana

Abstract. Production of banana (Musa spp.) is a major economic activity in the humid tropical region of Mexico. Any damage to the fruit is unacceptable for domestic and export markets. The aim of this study was to determine the pest species that damage the epidermis of banana fruit and evaluate the intensity of damage in different development stages of banana bunches and its incidence in commercial plantations. The study was at ‘Giant Dwarf’ Musa AAA Cavendish banana plantations at Teapa, Tabasco, from August 2010 to April 2012. The beetle Myochrous melancholicus Jacoby (Coleoptera: Chrysomelidae) was identified as the cause of the damage. Adults cause small, irregular and superficial cuts or incisions on the edges of the fruit, almost overlapping each other, which, when dry, form elongated scars. In infestations induced in the field, the species caused from 4.8 to 14.5% of damage fruits throughout the developmental period of banana bunches. The incidence of adults and damage was detected only during the ...

GAMBARAN KEPERCAYAAN TENTANG KHASIAT MENYIRIH PADA MASYARAKAT PAPUA DI KELURAHAN ARDIPURA I DISTRIK JAYAPURA SELATAN KOTA JAYAPURA

Indonesian people has long know the, betel leaf, areca nut, and lime is material to betel chewing. Chewing the betel leaf is believed can care teeth by ancestors. They are convinced that slacking can strengthen teeth, cure small cuts in the mouth, eliminate bad breath. Indigenous Papuans engage in slaughtering behavior because of the belief inherited from the ancestors. The frequency of betel chewing practiced by indigenous people of Papua is > 2 times a day by consuming more than two areca nuts and is believed to maintain good oral hygiene. Positive impacts which are felt when doing betel chewing namely; body feels fresh, elimination of bad breath, and restores solid teeth. While the negative impact shows thickness of the tongue, wound on the edge of the mouth, numbness of the tongue, and addicted to chewing betel. Beliefs about the efficacy from betel chewing make people do not take care of dental health. Communities experienced plaque build-up and dental caries. The purpose of this study is to determine the image of belief and the efficacy of betel chewing in Ardipura Village District of South Jayapura City. This study followed a qualitative design approach and study was phenomenology type, and descriptive through active participation, conducted interviews and observations using content analysis technique. The determination of informants in this study uses purposive sampling technique method. Results drawn from this study shows the behavior of betel chewing is believed to strengthen teeth, relieve toothache and drowsiness, eliminate bad breath and betel chewing as a from friendship.Keywords: Betel chewing, Belief, District of South Jayapura city

An experimental investigation of a new perfect bond technology for composite slabs

Steel-concrete composite slabs generally fail due to the debonding with separation of sections caused by longitudinal shear forces, regardless of the shape of the sheeting profile or the design of the embossments. This article presents an innovative full-connection bonding technology, consisting of producing bands of many small crown-shaped cuttings in the profile webs as a replacement for the embossments. The new technology has been tested on three commercial sheeting profiles. The results of the investigation show that full connection is achieved with the new system, i.e., yielding of both materials occurs without any slip, in contrast to the partial connection of traditional embossments. The longitudinal shear strengths are 1.4–7 times higher. The specimens tested include the use of conventional galvanized steel and concrete, as well as ferritic stainless steel and lightweight aggregate concrete.

Graph Bisection with Pareto Optimization

We introduce FlowCutter, a novel algorithm to compute a set of edge cuts or node separators that optimize cut size and balance in the Pareto sense. Our core algorithm heuristically solves the balanced connected st -edge-cut problem, where two given nodes s and t must be separated by removing edges to obtain two connected parts. Using the core algorithm as a subroutine, we build variants that compute node separators that are independent of s and t . From the computed Pareto set, we can identify cuts with a particularly good tradeoff between cut size and balance that can be used to compute contraction and minimum fill-in orders, which can be used in Customizable Contraction Hierarchies (CCHs), a speed-up technique for shortest-path computations. Our core algorithm runs in O ( c ∣ E ∣) time, where E is the set of edges and c is the size of the largest outputted cut. This makes it well suited for separating large graphs with small cuts, such as road graphs, which is the primary application motivating our research. For road graphs, we present an extensive experimental study demonstrating that FlowCutter outperforms the current state of the art in terms of both cut sizes and CCH performance. By evaluating FlowCutter on a standard graph partitioning benchmark, we further show that FlowCutter also finds small, balanced cuts on nonroad graphs. Another application is the computation of small tree decompositions. To evaluate the quality of our algorithm in this context, we entered the PACE 2016 challenge [13] and won first place in the corresponding sequential competition track. We can therefore conclude that our FlowCutter algorithm finds small, balanced cuts on a wide variety of graphs.

Transurethral plasmakinetic enucleation of prostate and suprapubic small cut in the treatment of patients with moderate and severe benign prostatic hyperplasia and multiple bladder stones

Objective To discuss the safety and efficiency of transurethral plasmakinetic enucleation of prostate and suprapubic small cut in the treatment of patients with moderate and severe benign prostatic hyperplasia and multiple bladder stones. Methods A total of 18 patients with moderate and severe benign prostatic hyperplasia and multiple bladder stones underwent plasmakinetic enucleation. Enucleation of the prostate was pushed into the bladder. We made a small suprapubic incision (3~4 cm) to remove prostate tissue and bladder stones completely. Results All operations of the 18 patients were successful. The weight of prostate tissue was 65~256 g, with an average of 87.6 g. Bladder stones were 3~21, with an average of 6.3. The mean operative time of prostate enucleation was 20~40 min. The time of removing the gland and bladder stones was 15~30 min. The volume of blood loss during operation was 50~100 mL. The postoperative time of wash the bladder continuously was 24~28 hours. The urethral catheters were removed after 4~5 days. Temporary incontinence occurred in one patient, but it disappeared after mention anal training 5 days later. All the 18 cases were followed up from 2 to 34 months, with an average of 19.8 months. There was no blood and all had good urination. International Prostate Symptom Scores (IPSS) one month after operation decreased from 25.6 to 7.4. The mean volume of Qmax increased from 6.3 mL/s before operation to postoperative 17.6 mL/s. Conclusions Transurethral plasmakinetic enucleation of prostate and suprapubic small cut in the treatment of patients with moderate and severe benign prostatic hyperplasia and multi-ple bladder stones is safe and effective. With simple operation and fewer complications, it should be applied more widely for patients. Key words: Prostatic Hyperplasia; Urinary Bladder Calculi; Prostatectomy

Influence of different cultivars of Phoenix dactylifera L-date fruits on blood clotting and wound healing

Objective: To investigate different types of dates and medical properties of influencing blood clotting and wound healing in an animal model. Methods: Three different cultivars of dates (Ajwa, Khalas, and Fardh) were examined in-vivo, for blood clotting and wound healing using CD1 mice of both sexes. Study of toxicity to animals was performed accordingly prior to further investigations. The ethanolic extracts were given orally to animals as a constituent in their daily water. Blood samples were obtained from the mice inferior vena cava to carry out the prothrombin time (PT) assay using the manual method and confirmed using a semi-automated machine. The bleeding time (BT) assay was performed using the cutting technique. In the wound healing analysis, a small cut (5-10 mm) in the skin overlying the thigh was conducted in all mice under anesthesia. The diameter of the cut and healing status were measured on a daily basis throughout the time of the experiment using a roller. Results: Ajwa was able to elevate both PT and BT (P

Cicada (<i>Magicicada</i>) Tree Damage Detection Based on UAV Spectral and 3D Data

The periodical cicadas appear in regions of the United States in intervals of 13 or 17 years. During these intervals, deciduous trees are often impacted by the small cuts and eggs they lay in the outer branches which soon die off. Because this is such an infrequent occurrence and it is so difficult to assess the damage across large forested areas, there is little information about the extent of this impact. The use of remote sensing techniques has been proven to be useful in forest health management to monitor large areas. In addition, the use of Unmanned Aerial Vehicles (UAVs) has become a valuable tool for analysis. In this study, we evaluated the impact of the periodical cicada occurrence on a mixed hardwood forest using UAV imagery. The goal was to evaluate the potential of this technology as a tool for forest health monitoring. We classified the cicada impact using two Maximum Likelihood classifications, one using only the high resolution spectral derived from leaf-on imagery (MLC 1), and in the second we included the Canopy Height Model (CHM)—derived from leaf-on Digital Surface Model (DSM) and leaf-off Digital Terrain Model (DTM)—information in the classification process (MLC 2). We evaluated the damage percentage in relation to the total forest area in 15 circular plots and observed a range from 1.03% -22.23% for MLC 1, and 0.02% - 10.99% for MLC 2. The accuracy of the classification was 0.35 and 0.86, for MLC 1 and MLC 2, based on the kappa index. The results allow us to highlight the importance of combining spectral and 3D information to evaluate forest health features. We believe this approach can be applied in many forest monitoring objectives in order to detect disease or pest impacts.

Othello by Shakespeare's Globe

Reviewed by: Othelloby Shakespeare's Globe Gemma Miller OthelloPresented at Shakespeare's Globe, London. 07 20– 10 13, 2018. Directed by Claire van Kampen. Production Design by Jonathan Fensom. Costumes by Lorraine Ebdon-Price. Music by Bill Barclay. Choreography by Antonia Franceschi. With Sheila Atim (Emilia), Catherine Bailey (Bianca/Doge of Venice), William Chubb (Brabantio/Montano), Steffan Donnelly (Roderigo), André Holland (Othello), Micah Loubon (Chorus), Ira Mandela Siobhan (Chorus), Aaron Pierre (Cassio), Mark Rylance (Iago), Clemmie Sveaas (Chorus), Badria Timimi (Lodovica), Jessica Warbeck (Desdemona), and others. The Globe's 2018 revival of Othello, the fourth since it opened in 1997, saw the welcome return of former Globe Musical Director Clare van Kampen as director, and former Globe Artistic Director Mark Rylance in the role of Iago. Iago was to be Rylance's first Shakespearean performance at the Globe since his critically acclaimed performances in the "original practice" productions of Twelfth Nightand Richard IIIin 2012. Olivia, in particular, was a role he seemed born to play and I was intrigued to see how he would handle the part of Iago and, perhaps more pertinently, whether André Holland's Othello would be able to hold his own against such an experienced Globe performer. [End Page 695] Van Kampen declared in the program that she was "going for a heavy cut" with the text, a decision which I felt added to rather than detracted from the drama. The bawdy exchange between Iago and Desdemona at the quayside (2.1) was significantly reduced, and the two exchanges with the Clown in 3.1 and 3.4 were excised in their entirety. This meant that the second half opened with Desdemona asking Emilia, "[w]here should I lose that handkerchief?," thus drawing our attention to the significance of this central plot device. There were some small cuts to Iago's monologues. For instance, he ended his soliloquy in 2.3 with "Divinity of hell" (345), at which point he shook hands with one of the groundlings. This meant that we lost two of Iago's greatest pronouncements: "When devils will the blackest sins put on / They do suggest at first with heavenly shows" (2.3.346–47), and "So will I turn her virtue into pitch" (2.3.355). However, his simple gesture created a sense of complicity with the audience that more than compensated for the lost lines. The overall result of the excisions was a clear production that sacrificed none of the music of Othellowhile achieving a slick, dramatic pace that drove relentlessly through to its inevitable and tragic conclusion. The play opened with Roderigo struggling to keep up with Iago as he raced towards Brabantio's house, weaving around the two columns in frantic figure-of-eights. From this opening scene, Iago was established as a master-manipulator, leading not just the credulous gull Roderigo, but all of the other characters, "by th' nose" (1.3.400) with his scheming. The sense of Iago as a Prospero-like puppet master continued throughout the play. For instance, he stood on the balcony upstage left during the encounter between Othello, Brabantio, and the Duke in 1.3, watching and calculating with a silent sense of menace. He arrived triumphantly in Cyprus on a cart drawn through the groundlings in 2.1, only releasing a cramped and contorted Roderigo from an oversized suitcase some one hundred lines later. He led the dancing and drinking in 2.3 with the gusto of an "honest" and affable officer, his "stoup of wine" (2.3.27) a large crate with several rattling bottles. I have long been baffled by those who claim that Iago is without motive. It has always been clear to me that it is Iago's sexual jealousy that drives him, rather than a sense of motiveless evil, a reading that Rylance's performance reinforced with a clarity that I have never experienced before. This was most notable during the rambunctious drinking scene in Cyprus, during which he watched jealously over Emilia and led her away from Cassio on more than one occasion. He was also evidently discomfited by the overt manifestations of physical intimacy between Othello and Desdemona. [End...

A wandering Weddell seal (Leptonychotes weddellii) at Trindade Island, Brazil: the extreme sighting of a circumpolar species

Records of vagrant marine organisms provide important information on oceanographic anomalies and the changing environment. We report on an immature Weddell seal, Leptonychotes weddellii, sighted at Calheta Beach in Trindade Island (20°31′S 29°19′W), Brazil, on July 9, 2015. A number of injuries were noted, including blisters on the dorsal surface of the body and a small cut at the right-hand side distal portion of the mandible. Based on its size and the state of fusion of cranial sutures, we suggest that it was born in the 2014 austral spring and was possibly 8–10 months old. We suggest that it comes from the South Shetland Islands, Antarctic Peninsula. This is the closest breeding location of this species. This sighting is the northernmost of L. weddellii, being at least ~ 5140 km from the Antarctic Peninsula (63°12′S 55°04′W) and ~ 2840 km north from the second northernmost sighting of this species in Uruguay.

Growth traits of juvenile American chestnut and red oak as adaptations to disturbance

American chestnut (Castanea dentata) was a dominant species in eastern North America prior to the importation of chestnut blight. In light of recent efforts to restore viable populations of chestnut in eastern forests, an increased understanding of its association with other co‐occurring, disturbance‐adapted oak species is necessary. We evaluated crown architecture and leaf morphology in juvenile chestnut and red oak (Quercus rubra) to assess potential differences in establishment strategies of both species. We also investigated differences in nonstructural carbohydrate reserves and whole tree biomass partitioning between species. Seedlings of both species were planted in forest stands treated either with midstory removal or small patch cuts, simulating potential restoration plantings. After 5–7 years, chestnut's allocation to its root system was lower than red oak's, with chestnut saplings instead diverting resources to branches and foliage. Chestnut had lower leaf area index, greater crown projection area, and higher specific leaf area than red oak, indicating the species may have an advantage in shaded understories. There were only minor differences in nonstructural root carbohydrate reserves, between red oak and American chestnut, indicating that chestnut may respond similarly to oak by resprouting after disturbances topkill young saplings. We suggest that American chestnut has morphological and physiological attributes that allow it to function as an opportunistic and plastic species that can utilize gaps to facilitate its canopy recruitment, yet still persist after occasional surface fire. This knowledge can guide restoration strategies for this iconic species of the eastern temperate forest region.

Canadian Consumer Food Safety Practices and Knowledge: Foodbook Study

Understanding consumers' food safety practices and knowledge supports food safety education for the prevention of foodborne illness. The objective of this study was to describe Canadian consumer food safety practices and knowledge. This study identifies demographic groups for targeted food safety education messaging and establishes a baseline measurement to assess the effectiveness of food safety interventions over time. Questions regarding consumer food safety practices and knowledge were included in a population-based telephone survey, Foodbook, conducted from November 2014 to March 2015. The results were analyzed nationally by age group and by gender. The results showed that approximately 90% of Canadians reported taking the recommended cleaning and separating precautions when handling raw meat to prevent foodborne illness. Only 29% of respondents reported using a food thermometer when cooking any meat, and even fewer (12%) reported using a food thermometer for small cuts of meat such as chicken pieces. The majority (>80%) of Canadians were aware of the foodborne illness risks related to chicken and hamburger, but fewer (<40%) were aware of the risks related to frozen chicken nuggets, alfalfa sprouts, soft unpasteurized cheese, and unpasteurized juices. Generally, men were less likely to follow cooking instructions on packaging and took fewer steps to prevent cross-contamination than women. The youngest (18 to 29 years) age group was less likely to take steps to avoid cross-contamination and was less aware of the risks associated with eating an undercooked hamburger. The oldest (60+ years) respondents were less likely to be aware of the risks associated with raw eggs, alfalfa sprouts, and unpasteurized juice than the middle (30 to 59 years) age group. As a priority, food safety education in Canada should focus on increasing people's awareness of high-risk foods, specifically foods for which the awareness of risk found in this study was low; targeting messaging to demographic groups as appropriate; and promoting the use of food thermometers when cooking meat and poultry.

Direct amplification of biological evidence and DVI samples using the Qiagen Investigator 24plex GO! Kit

Omitting DNA extraction and quantitation can save valuable time in criminal investigations and disaster victim identification (DVI) efforts. In this study, we applied different collection methods and a combination of direct amplification and lysis to various sample types in combination with the Qiagen Investigator 24plex GO! Kit. This “megaplex” kit was designed for direct PCR of DNA references, and validated with Investigator STRGO! lysis buffer. Preliminary experiments resulted in different approaches for each sample type. Missing person reference and/or post-mortem samples like hair roots, toothbrush bristles, muscle tissue and bone shavings could be successfully typed after a Proteinase K lysis step with 2mL of the volume as PCR input. Blood and saliva stains, touched fabrics and fingerprints on glass were tested with direct PCR after collection using tape lifts, cuttings, and various swab types. Using COPAN microFLOQ swabs is the most convenient collection method, but other methods, like tape lifts and small swab cuttings work as well.The two quality standards incorporated in the Qiagen 24plex kits are helpful for trouble shooting. This is especially important in the absence of Q-PCR data. Several samples, e.g. paper tissue cuttings and surface swabs from fingerprints, eye glasses and razors showed inhibition. The PCR may have been affected by the loss of reaction volume through absorption by the swab. Sources of inhibitors could have been the swab or tissue substrate, or the items, e.g. make-up on eye glasses.

Non-model-based multiple damage identification of beams by a continuously scanning laser Doppler vibrometer system

An effective non-model-based multiple damage identification method for beams by using a continuously scanning laser Doppler vibrometer (CSLDV) system is presented. Velocity response of a beam along a scan line under sinusoidal excitation is measured by the CSLDV system and a spatially dense operating deflection shape (ODS) of the beam along the scan line is obtained by the demodulation method from velocity response. An ODS of an associated undamaged beam is obtained by using a polynomial with a proper order to fit the ODS from the demodulation method. The curvature of an ODS (CODS) is used to identify abnormality induced by multiple damage. A curvature damage index (CDI) using differences between CODSs associated with ODSs that are obtained by the demodulation method and the polynomial fit is proposed to identify multiple damage. A normalized average CDI obtained by averaging CDIs at different excitation frequencies is defined to further assist multiple damage identification. Experiments on three beams with three damage on each beam in the form of three small cuts are conducted. Widths and depths of the three damage are varied from 3mm to 9mm with an increment of 3mm and from 5% thickness reduction to 15% with an increment of 5%, respectively, and their effects on ODSs, CODSs, and CDIs are investigated. Five frequencies obtained by rounding the first through fifth natural frequencies of the beams and one arbitrarily selected frequency that is not close to any natural frequency of the beams are used as sinusoidal excitation frequencies. Each damage is successfully identified near regions with consistently high values of CDIs at different excitation frequencies. The three damage on each beam is successfully identified with the normalized average CDI by obvious peaks at locations of the three damage.

Magnetohydrodynamic sausage waves in current-carrying coronal tubes

Magnetohydrodynamic (MHD) sausage waves in a coronal loop consisting of a core with longitudinal magnetic field and a current-carrying annulus with azimuthal magnetic field in the presence of plasma pressure are studied. As the plasma pressure is introduced to the loop a narrow band of infinite slow waves appear in the dispersion diagram, and the oscillation frequency of the fast sausage waves increases. In the loops with thinner annulus, more fast sausage waves with higher radial mode numbers are supported by the loop, and the fast sausage waves have smaller cut off wave numbers. The eigenfunction of the long wavelength fast sausage wave supported by the current-carrying loop, in the case of low density contrast, is similar to the eigenfunction of the slow sausage wave in a straight homogeneous loop with the maximum frequency of the frequency band. Other slow sausage waves both in a straight homogeneous loop and a current-carrying loop do not perturb the surrounding environment substantially.

Improved bounds and algorithms for graph cuts and network reliability

AbstractKarger (SIAM Journal on Computing, 1999) developed the first fully‐polynomial approximation scheme to estimate the probability that a graph G becomes disconnected, given that its edges are removed independently with probability p. This algorithm runs in time to obtain an estimate within relative error . We improve this run‐time through algorithmic and graph‐theoretic advances. First, there is a certain key sub‐problem encountered by Karger, for which a generic estimation procedure is employed; we show that this has a special structure for which a much more efficient algorithm can be used. Second, we show better bounds on the number of edge cuts which are likely to fail. Here, Karger's analysis uses a variety of bounds for various graph parameters; we show that these bounds cannot be simultaneously tight. We describe a new graph parameter, which simultaneously influences all the bounds used by Karger, and obtain much tighter estimates of the cut structure of G. These techniques allow us to improve the runtime to ; our results also rigorously prove certain experimental observations of Karger and Tai (Proc. ACM‐SIAM Symposium on Discrete Algorithms, 1997). Our rigorous proofs are motivated by certain non‐rigorous differential‐equation approximations which, however, provably track the worst‐case trajectories of the relevant parameters. A key driver of Karger's approach (and other cut‐related results) is a bound on the number of small cuts: we improve these estimates when the min‐cut size is “small” and odd, augmenting, in part, a result of Bixby (Bulletin of the AMS, 1974).

Enhancing Network Robustness via Shielding

We consider shielding critical links to enhance the robustness of a network, in which shielded links are resilient to failures. We first study the problem of increasing network connectivity by shielding links that belong to small cuts of a network, which improves the network reliability under random link failures. We then focus on the problem of shielding links to guarantee network connectivity under geographical and general failure models. We develop a mixed integer linear program (MILP) to obtain the minimum cost shielding to guarantee the connectivity of a single source–destination pair under a general failure model, and exploit geometric properties to decompose the shielding problem under a geographical failure model. We extend our MILP formulation to guarantee the connectivity of the entire network, and use Benders decomposition to significantly reduce the running time. We also apply simulated annealing to obtain near-optimal solutions in much shorter time. Finally, we extend the algorithms to guarantee partial network connectivity, and observe significant reduction in the shielding cost, especially when the geographical failure region is small.

Minimally invasive unilateral pedicle screws and a translaminar facet screw fixation and interbody fusion for treatment of single-segment lower lumbar vertebral disease: surgical technique and preliminary clinical results

BackgroundConventional open transforaminal lumbar interbody fusion (TLIF) using unilateral pedicle screws and a translaminar facet screw has been performed for many years with good results. The outcomes of minimally invasive TLIF (MIS TLIF) are similar to the good outcomes of open TLIF, with the additional benefits of reducing iatrogenic injury, shortening hospital stays, and reducing the recovery duration. Instead of using small cuts on both sides, we performed MIS TLIF through a single cut using unilateral pedicle screws and a translaminar facet screw. The operative feasibility, efficacy safety, and benefits of single-level MIS TLIF of such techniques require further clarification.MethodsA total of 60 patients with various single-segment lower lumbar vertebral diseases were treated in our department from January 2010 to March 2013. All the patients were initially performed single-level MIS TLIF using a hybrid construction of unilateral pedicle screws and a translaminar facet screw. Patient demographics and operative data were collected. The clinical outcomes were assessed before surgery and 3, 6, 12, and 24 months after surgery using the visual analog scale (VAS) for back and leg pain and the Oswestry Disability Index (ODI). Radiologic assessment of the lumbar spine with static and dynamic plain radiographs was performed 3, 6, 12, and 24 months after surgery. The fusion rates were assessed by an independent radiologist 2 years after surgery according to the Bridwell interbody fusion grading system.ResultsNo patients experienced significant postoperative complications. Excepting two cases, 58 cases were followed up for 24–38 months, averaged 29.9 ± 4.1 months. The patients’ average age was 46.6 ± 11.5 years, operative time 109.7 ± 17.8 min, intraoperative blood loss 67.3 ± 29.7 ml, length of incision 29.0 ± 3.2 mm, fluoroscopy time 31.1 ± 7.2 s, time to ambulation 20.3 ± 7.0 h, length of hospital stay 5.1 ± 1.1 days, and length of the translaminar facet screw 51.7 ± 3.4 mm. Screw position results: type I, 54 cases with 54 segments; type II, four cases with four segments. There were two (3.4%) translaminar facet screw failures, which were intraoperatively converted to a bilateral pedicle screw fixation procedure and excluded from the research. The postoperative images showed good positioning of the hybrid internal fixation, and all of the translaminar facet screws penetrated the facet joint. Two (3.6%) translaminar facet screws penetrated the lateral lamina and two (3.6%) translaminar facet screws penetrated the medial lamina without any serious neural complications. During the follow-up, there was no screw loosening or pedicle fracture observed. The VAS and ODI scores were significantly improved compared with the preoperative scores (P < 0.05), and the symptoms disappeared gradually. Fifty-one patients (87.9%) achieved grade I fusion radiographically at the final follow-up.ConclusionsMIS TLIF using a hybrid construction of unilateral pedicle screws and a translaminar facet screw is safe and effective in the treatment of single-segment lower lumbar vertebral disease, and it can be used as an optimal choice for fixation and fusion of some single-segment lower lumbar vertebral diseases.

A Reliable and Efficient Approach to Numerically Controlled Programming Optimization for Multiple Largest Tools Cutting Blisks Patch by Patch in the Blisks' Four-Axis Rough Machining

As an important component of gas turbine engines, a blisk (or an axial compressor) is complex in shape. The pressure and suction surfaces of the blisk blades are designed with free-form surfaces, and the space (or the channel) between two adjacent blades varies significantly. Thus, some blade patches can be machined with large-diameter cutters, and some patches have to be cut with small-diameter cutters. Usually, the blisk's material is high-strength stainless steel, titanium alloy, or difficult-to-cut material. The cutting force and temperature in roughing the blisks are high, and thus, the machine tool should be rigid and the cutters should be as large as possible. Therefore, the best industrial practice of rough-machining the blisks is to use multiple largest solid and indexable end-mills to cut them patch by patch on a four-axis computer numerically controlled (CNC) machine. The reasons are (a) four-axis CNC machines are more rigid than five-axis CNC machines, (b) multiple largest cutters are used for higher cutting speeds and feed rates and for less machining time and longer tool life, and (c) if indexable end-mills can be used, the tooling costs are further reduced. For the blisk finishing, a small cutter is often used on a five-axis CNC machine, which is not a topic of this work. However, due to complex shape of the blades, it is quite difficult to automatically optimize the blade surface partition so that each surface patch can be cut with a largest cutter in four-axis blisk rough machining. In the conventional way, numerically controlled (NC) programmers often employ small-diameter solid end-mills and plan their paths to cut the blades layer by layer in four-axis milling. Unfortunately, the machining efficiency of this way is low, and the end-mills wear out quickly. This work establishes a theoretical and completed solution. A simplified optimization model of the largest allowable diameter of the theoretical cutter at a cutter contact (CC) point is established, and an efficient and reliable solver is proposed. The blade surfaces are automated partitioned for largest cutters to the surfaces patch by patch in four-axis rough machining. This approach is efficient and reliable, and it is viable in theory and practical in industry.