Extensive Operations Research Articles

The Effect of Farming System Type on Piglet Production

Reproductive performance of sows is the main factor influencing the profitability of piglet production, and simultaneously it is a basic indicator of farm management quality. The aim of this study was to compare reproductive performance of sows from intensive and extensive feeder pig operations and the costs on those farms. Evaluated were 42 sows from extensive pig farming and 464 sows from intensive pig farming. Lifelong performance was determined for all sows. The study's results show that sows from intensive pig farming achieved a mean 2.04 fewer lactations per lifetime and were culled earlier (P < 0.0001). The mean total number of live-born piglets was 11.59% lower among sows from intensive pig farming, but these sows achieved 23.35% (P < 0.0001) higher mean number of piglets per litter. Despite shorter mean productive life, sows from intensive pig farming were more profitable. Maximizing the reproductive potential of sows has positive effect on farm profitability, and simultaneously it has no negative effect on sows' reproductive performance.

Solving a Poisson Equation with Singularities by the Least-Squares Collocation Method

New h-, p-, and hp-versions of the least-squares collocation method (LSCM) are proposed and implemented for solving the Dirichlet problem for a Poisson equation. Examples are considered of solving problems with singularities such as large gradients, fast growing rate of solution derivatives with increasing order of differentiation, discontinuities of second-order derivatives at angular points of the domain boundary, and solution oscillations with various frequencies for an infinite discontinuity point for derivatives of any order. The new versions of the method are based on a special selection of collocation points in the roots of Chebyshev polynomials of the first kind. The basis functions are defined as products of Chebyshev polynomials. The behavior of numerical solutions on a sequence of grids with an increasing degree of the approximating polynomial is analyzed by using exact analytical solutions. Formulas for the extension operation of transition from a coarse grid to a finer one on a multi-grid complex in the Fedorenko method are obtained.

Determinants and dimensions of the shift in Turkish behavior towards northern Syria since 2016

Purpose The escalation of Turkish intervention in Arab internal affairs before and after the revolutions of the Arab Spring, particularly the military intervention. Sometimes Ankara threatens with military intervention and sometimes establishes large military bases in Arab countries: Qatar, Somalia and Iraq. Moreover, it carries out extensive military operations within the borders of some Arab countries such as Iraq and Syria. This type of behavior requires a study that takes into consideration the reasons of such behavior and future implications on the relations between the Arab and Turkish parties. Design/methodology/approach The theoretical framework of the study will follow neorealism, as the basis for understanding Turkish pragmatic foreign policy adopted in managing its international relations and interests with various countries. Findings The situation in Afrin after a year of Turkish occupation confirms this. Erdogan may not go ahead with a new military operation in east Euphrates and northern Syria. He may prefer instead he may deem it better to control the safe area in the north through the revival of the agreement of Adana of 1998. However, Turkey's desire to control northern Syria, which represents a quarter of the country, faces tough resistance of Turkish groups, Russian-Syrian rejection and European-American resentment. Control of the Syrian north may be subject to concessions and consensus among these powers without excluding any of them. Research limitations/implications States in the international system, such as companies in the local economy, have the same main interest: that’s survival. It is worth noting that Waltz’s neorealistic theory cannot be applied to domestic national politics. It cannot contribute to the development of state policies relating to its international and internal affairs. His theory only helps to explain the reason behind the similar behavior of countries despite having different forms of governments and diversity of political ideologies. It also explains why the comprehensive international relations have not changed despite the growing decentralization of these countries. Originality/value How does neorealism explain Turkish military intervention in Syria since 2016?

983 TUNNEL ASSISTED "FUNNEL” RESECTION: ESD OF LARGE CIRCUMFERENTIAL EGJ/CARDIA SIEWERT 2 LESION

A 74year old woman with alopecia, CAD on Plavix and Non-Hodgkin’s lymphoma s/p chemotherapy and radiation of the upper abdomen underwent endoscopy to evaluate dysphagia. It revealed a stenotic esophagus with diameter of 12-15 mm. Bougie dilation was performed. Three gastric lesions were seen: A large Paris IIa circumferential lesion extending from 1 cm proximal to the Z line to 4-5 cm distal to the Z line, a 4cm Paris IIb lesion at the proximal greater curvature lesion and a 2 cm cardia Paris Is lesion. Biopsy of all 3 lesions revealed adenoma. The patient was referred to us for ESD of the 3 lesions. There is scant literature on ESD of Siewert II EGJ lesions of gastric origin and virtually no literature on ESD for completely circumferential such lesions (Kim et al Surg Endo 2018). Circumferential en bloc resection of such lesions is challenging due to: 1. the narrow esophageal lumen and high EGJ vascularity, particularly in this patient with stenotic esophagus, post radiation fibrosis, and antiplatelet therapy. 2. the difficulty in achieving favorable scope position for ESD in the fundus and anterior cardia. Double bending scopes are helpful in this setting but not available in the US (Hamada VideoGIE 2019). We present a video that highlights techniques that can be used to achieve en bloc resection in such challenging lesions. The large circumferential lesion was removed in 424 minutes, specimen measured 7cm x 7cm. As shown on the video the “funnel” shaped specimen was affixed on cork in a way that orientation is preserved with the esophageal portion protruding through a hole. The second lesion was removed in 55 minutes, specimen measured 5.5 cm x 3.5 cm. The third lesion was removed in 44 minutes, specimen measured 2.5 cm x 2 cm. In all 3 cases, pathology revealed R0 resection of adenoma. The patient had delayed bleeding on POD#1 requiring endoscopic hemostasis. She also developed EGJ stricture requiring 7 endoscopic dilations over 3.5 months until resolution. The presented video includes the video of her follow-up endoscopy at 1 year showing well healed scars with no residual adenoma. We present an en bloc, R0 “funnel” resection of a challenging EGJ/cardia circumferential lesion in a patient with stenotic esophagus and post radiation fibrosis. A variety of advanced techniques were used to achieve successful en bloc resection including multiple tunnels, a 360 degree endoscope loop (previously described by us for EFTR in the fundus, VideoGIE 2019), omental plug for microperforation closure, and per-os traction using an external grasper. Even with expert skills and techniques the operator should expect long operative times for such resections but they are of major benefit to patients particularly for pre-cancerous lesions as they spare them extensive esophago-gastrectomy operations.

Apical length governs computational diversity of layer 5 pyramidal neurons.

Anatomical similarity across the neocortex has led to the common assumption that the circuitry is modular and performs stereotyped computations. Layer 5 pyramidal neurons (L5PNs) in particular are thought to be central to cortical computation because of their extensive arborisation and nonlinear dendritic operations. Here, we demonstrate that computations associated with dendritic Ca2+ plateaus in mouse L5PNs vary substantially between the primary and secondary visual cortices. L5PNs in the secondary visual cortex show reduced dendritic excitability and smaller propensity for burst firing. This reduced excitability is correlated with shorter apical dendrites. Using numerical modelling, we uncover a universal principle underlying the influence of apical length on dendritic backpropagation and excitability, based on a Na+ channel-dependent broadening of backpropagating action potentials. In summary, we provide new insights into the modulation of dendritic excitability by apical dendrite length and show that the operational repertoire of L5PNs is not universal throughout the brain.

Extension of Besov-Q Type Spaces via Convolution Operators with Applications

In this paper, we use regular wavelets to investigate the extension problem of a class of Besov-Q spaces $${\dot{B}}^{\alpha ,\lambda }_{p,p}({\mathbb {R}}^{n})$$ . We introduce an extension operator $$\Pi _{\psi }$$ generated via $$\psi $$ , and prove that $${\dot{B}}^{\alpha ,\lambda }_{p,p}({\mathbb {R}}^{n})$$ can be extended to function spaces $${\mathscr {C}}^{\alpha }_{p,\lambda }({\mathbb {R}}^{n+1}_{+})$$ via $$\Pi _{\psi }$$ . Conversely, inspired by the reproducing formula, we construct a trace operator $$\pi _{\phi }$$ in the sense of distributions. We obtain that $${\mathscr {C}}^{\alpha }_{p,\lambda }({\mathbb {R}}^{n+}_{+})$$ can also be pulled back to $${\dot{B}}^{\alpha ,\lambda }_{p,p}({\mathbb {R}}^{n})$$ under the operation of $$\pi _{\phi }$$ . As an application, we establish a characterization of some kind of harmonic function spaces $${\mathscr {H}}^{\alpha ,\eta }_{p,\lambda }({\mathbb {R}}^{n+1}_{+})$$ .

Association of the Risk of a Venous Thromboembolic Event in Emergency vs Elective General Surgery

Trauma patients have an increased risk of venous thromboembolism (VTE), partly because of greater inflammation. However, it is unknown if this association is present in patients who undergo emergency general surgery (EGS). To investigate whether emergency case status is independently associated with VTE compared with elective case status and to test the hypothesis that emergency cases would have a higher risk of VTE. This retrospective cohort study used the American College of Surgeons National Surgical Quality Improvement Program database from January 1, 2005, to December 31, 2016, for all cholecystectomies, ventral hernia repairs (VHRs), and partial colectomies (PCs) to obtain a sample of commonly encountered emergency procedures that have elective counterparts. Emergency surgeries were then compared with elective surgeries. The dates of analysis were January 1 to 31, 2019. The primary outcome was VTE at 30 days. A multivariable analysis controlling for age, sex, body mass index, bleeding disorder, disseminated cancer, laparoscopy approach, and surgery type was performed. There were 604 537 adults undergoing surgical procedures over 12 years (mean [SD] age, 55.3 [16.6] years; 61.4% women), including 285 847 cholecystectomies, 158 500 VHRs, and 160 190 PCs. The rate of VTE within 30 days was 1.9% for EGS and 0.8% for elective surgery, a statistically significant difference. Overall, 4607 patients (0.8%) had deep vein thrombosis, and 2648 patients (0.4%) had pulmonary embolism. A total of 6624 VTEs (1.1%) occurred in the cohort. As expected, when VTE risk was examined by surgery type, the risk increased with invasiveness (0.5% for cholecystectomy, 0.8% for VHR, and 2.4% for PC; P < .001). On multivariable analysis, EGS was independently associated with VTE (odds ratio [OR], 1.70; 95% CI, 1.61-1.79). Also associated with VTE were open surgery (OR, 3.38; 95% CI, 3.15-3.63) and PC (OR, 1.86; 95% CI, 1.73-1.99). In this cohort study, emergency surgery and increased invasiveness appeared to be independently associated with VTE compared with elective surgery. Further study on methods to improve VTE chemoprophylaxis is highly recommended for emergency and more extensive operations to reduce the risk of potentially lethal VTE.

Robust atlas generation via angle-based segmentation

We present a robust method to generate atlases with low isometric distortion and high packing efficiency. Given a surface that has been cut to disk topology, the algorithm contains four steps: (1) computing a bijective parameterization with low isometric distortion; (2) partitioning the input parameterized charts into a set of rectangle-like patches; (3) mapping rectangle-like patches onto rectangles that are packed into a rectangular domain; and (4) reducing parameterization distortion while maintaining high packing efficiency and bijection. Since there have been elegant and robust solutions for the first, third, and fourth steps, we focus on the second step. Central to the second step is a novel and robust segmentation technique. To improve the robustness of the segmentation, we first deform the parameterized charts to straighten their boundaries while aligning with the axes as much as possible, bounding the deformation distortion, and not introducing intersecting boundaries. Since rectangle-like patches are preferred for the third and fourth steps, we segment the deformed charts by decomposing concave interior angles into several interior angles close to π2 or π. To this end, we develop four types of operations: (i) bridging operation, (ii) extension operation, (iii) vertical line operation, and (iv) bisector operation. The pre-deformation process makes our heuristic segmentation very simple and effective. We demonstrate the efficacy of our method on various complex models. Compared to other state-of-the-art methods, our method achieves higher robustness.

Whitney extension operators with arbitrary loss of differentiability

For a compact set K⊂Rd we characterize the existence of a linear extension operator E:E(K)→C∞(Rd) for the space of Whitney jets E(K) with a certain loss of derivatives σ, that is, the operator satisfies the following continuity estimates for all n∈N0 and all F∈E(K)sup⁡{|∂αE(F)(x):|α|≤n,x∈Rd|}≤Cn‖F‖σ(n), where ‖⋅‖σ(n) denotes the Whitney norm and the map σ:N0→N0 is monotonically increasing with σ(n)≥n and σ(0)=0. From our main result it follows directly that if a compact set K admits an extension operator, then it is always possible to construct a second extension operator resembling the original Whitney operators En:En(K)→Cn(Rd) where the evaluations of the jet occurring in the Taylor polynomials are approximated by measures.

Examining Students’ Responses to Teacher Translation Feedback: Insights From the Perspective of Student Engagement

This case study investigated students’ response to feedback in the lens of student engagement with teacher feedback on their translation work. Drawing upon data from multiple sources, including students’ translation assignments, classroom observations, semi-structured interviews, stimulated recalls, and other documents, it explored how three Chinese undergraduates engaged with the feedback affectively, behaviorally, and cognitively. The findings reveal that (a) the students went through varying mood swings, and their expectations and teacher-related beliefs impacted their judgments of the feedback; (b) their failure to undertake self-editing upon receiving feedback was attributable to both student individual factors and teacher practices; and (c) extensive cognitive and behavioral operations could contribute to students’ deeper understanding of the feedback. These indicate the complex and interrelated relationship among the three dimensions of student engagement and contribute to our limited knowledge on the interplay between teacher translation feedback and student responses. Pedagogical implications are put forward for translation teachers to provide feedback and improve translation students’ engagement.

Technological, cycle and actual productivity of the surfacing process in the restoration of parts of forest machines

Most forestry machines and mechanisms operate in adverse conditions: an abrasive medium at low temperatures, which impede lubrication of parts and components of mechanisms and affect the mechanical characteristics of metals; under significant loads caused by working conditions in the forest. Therefore, the issues of operation and repair of precisely logging machines are most relevant. Scientific research and best practices of repair enterprises currently have a significant number of studied methods for building up worn parts in the recovery process. Scientific research and best practices of repair enterprises currently have a significant number of studied methods for building up worn parts in the recovery process. The requirement to ensure high productivity of the extension operation is relevant and important. The most high-performance methods are metallization, casting, electro contact, surfacing. But the first two methods do not provide guaranteed adhesion to the base metal. When applying metal to a worn surface by surfacing, good adhesion and the possibility of obtaining a wear-resistant surface are ensured. When floating metal overhead, technological work is performed, which means “work to change the shape, properties, condition and position of the subject of labor. “Productivity of the equipment is determined by the amount of technological work performed for a certain period of time.

Reconstruction of Upper Third Ear Defects: Utility of a Limited Tanzer Reduction.

BACKGROUNDLarge ear defects (>3 cm) present a significant reconstructive challenge and often require extensive operations, which can lead to donor-site morbidity and contour abnormalities. Through our case series, we propose a limited Tanzer reduction, a novel modification of the well-recognized Tanzer technique, as a potential reconstructive option for traumatic and oncologic upper third ear defects.METHODSWe retrospectively reviewed patients who underwent planned ear reconstruction for large ear defects (>3 cm) at a university center by a single surgeon (WPT) over a five-year period. Demographics, complications, and need for revision surgery were recorded. A satisfaction survey was also completed.RESULTSFive patients met our inclusion criteria as they underwent ear reconstruction with the limited Tanzer reduction. All reconstructions followed oncologic resection for cutaneous malignancy. The mean follow-up was 760.2 days. No complications were encountered, and no revisions were required. All cases had good aesthetic outcomes. The satisfaction survey revealed no self-image distortion or social obstacles following the reconstruction.CONCLUSIONThe proposed limited Tanzer reduction technique was shown to be a safe, viable, functionally and aesthetically pleasing option for the reconstruction of large defects of the ear and thus should be part of the armamentarium of the reconstructive surgeon.

Longitudinal Cognitive Decline in a Novel Rodent Model of Cerebral Amyloid Angiopathy Type-1.

Cerebral amyloid angiopathy (CAA) is a small vessel disease characterized by β-amyloid (Aβ) accumulation in and around the cerebral blood vessels and capillaries and is highly comorbid with Alzheimer’s disease (AD). Familial forms of CAA result from mutations within the Aβ domain of the amyloid β precursor protein (AβPP). Numerous transgenic mouse models have been generated around expression of human AβPP mutants and used to study cerebral amyloid pathologies. While behavioral deficits have been observed in many AβPP transgenic mouse lines, relative to rats, mice are limited in behavioral expression within specific cognitive domains. Recently, we generated a novel rat model, rTg-DI, which expresses Dutch/Iowa familial CAA Aβ in brain, develops progressive and robust accumulation of cerebral microvascular fibrillar Aβ beginning at 3 months, and mimics many pathological features of the human disease. The novel rTg-DI model provides a unique opportunity to evaluate the severity and forms of cognitive deficits that develop over the emergence and progression of CAA pathology. Here, we present an in-depth, longitudinal study aimed to complete a comprehensive assessment detailing phenotypic disease expression through extensive and sophisticated operant testing. Cohorts of rTg-DI and wild-type (WT) rats underwent operant testing from 6 to 12 months of age. Non-operant behavior was assessed prior to operant training at 4 months and after completion of training at 12 months. By 6 months, rTg-DI animals demonstrated speed–accuracy tradeoffs that later manifested across multiple operant tasks. rTg-DI animals also demonstrated delayed reaction times beginning at 7 months. Although non-operant assessments at 4 and 12 months indicated comparable mobility and balance, rTg-DI showed evidence of slowed environmental interaction. Overall, this suggests a form of sensorimotor slowing is the likely core functional impairment in rTg-DI rats and reflects similar deficits observed in human CAA.

Main geological and mining factors affecting ground cracks induced by underground coal mining in Shanxi Province, China

As one of the largest coal-rich provinces in China, Shanxi has extensive underground coal-mining operations. These operations have caused numerous ground cracks and substantial environmental damage. To study the main geological and mining factors influencing mining-related ground cracks in Shanxi, a detailed investigation was conducted on 13 mining-induced surface cracks in Shanxi. Based on the results, the degrees of damage at the study sites were empirically classified into serious, moderate, and minor, and the influential geological and mining factors (e.g., proportions of loess and sandstone in the mining depth, ratio of rock thickness to mining thickness, and ground slope) were discussed. According to the analysis results, three factors (proportion of loess, ratio of rock thickness to mining thickness, and ground slope) play a decisive role in ground cracks and can be respectively considered as the critical material, mechanical, and geometric conditions for the occurrence of mining surface disasters. Together, these three factors have a strong influence on the occurrence of serious discontinuous ground deformation. The results can be applied to help prevent and control ground damage caused by coal mining. The findings also provide a direct reference for predicting and eliminating hidden ground hazards in mining areas.

Have we reached the turning point? Looking for evidence of SOC increase under conservation agriculture and cover crop practices

AbstractIncreasing soil organic carbon (SOC) stocks in agricultural soils is currently of special interest because it can help mitigate global warming through atmospheric carbon (C) sequestration. Recommended management practices, such as conservation agriculture (CA) and conventional tillage with cover crops (CC), could have significant implications for C sequestration potential. A field experiment was carried out in northeast Italy to compare the implementation of CA and CC with conventional agriculture (CV). The experiment began in 2010 on three farms to evaluate SOC stock variation over a 6‐year period. Two extensive soil sampling operations were conducted in 2011 and 2017 in 240 locations, for a total of 1,440 analysed soil samples, considering the SOC stratification within a 0–50‐cm profile. The results suggested that CA changed the SOC distribution rather than the total amount of SOC. Compared to CV, after the introduction of CA, a general increase in SOC (0.25 Mg C ha−1 y−1) was observed in the 0–30‐cm layer, whereas no stock variation was observed in the 0–50‐cm layer. In contrast, compared to CV, the use of CC decreased the SOC stocks by 0.74 Mg C ha−1 y−1 in the 0–50‐cm layer. Over a 6‐year period, no benefit in SOC sequestration was observed with CA and CC. However, we hypothesize that these findings could still be affected by transitory dynamics, highlighting the low soil reactivity to soil‐improving agricultural systems. A longer study period would be required to better understand the potential benefits of CA and CC on SOC sequestration.Highlights We hypothesized that conservation practices increase SOC after a 6‐year adoption No‐tillage enhanced SOC stratification in conservation agriculture C addition with cover crops induced SOC stock reductions due to a priming effect An SOC increase was not observed after 6 years of conservation practices

Beneficial Ownership in Cash Pooling Arrangements

Cash pooling is a method of managing financial resources, which works well primarily in enterprises with an extensive corporate structure and operating within capital groups. The choice of a given form of cash pooling will depend on the entrepreneur’s individual preferences. Although using this method has many advantages, it still raises legal doubts. There is a lack of provisions in Poland that would precisely regulate this type of greement. In many cases, the design of the cash pooling agreement is similar to a loan agreement. However, it is worth paying attention to the basic differences, such as the fact that the essence of cash pooling is not an obligation to transfer a specific monetary value to an entity specified in the contract. These and other specific features of cash pooling agreements mean that it is not always obvious to which entity and on what terms an entity can be granted the status of beneficial owner. An additional, verification obligations imposed on the Polish payer and the need to act with due diligence are practical impediments.

Do Operations in Corrupt Foreign Countries Affect Auditor Behavior?

Auditors are required by the Foreign Corrupt Practices Act and other rules to evaluate the probability that a firm’s management bribes foreign government officials. However, anecdotal evidence suggests that auditors do not always follow the rules. In this study, we examine the role that international anti-bribery cooperation plays in auditors’ reaction to foreign corruption risk. In difference-in-differences analyses, we find that the staggered implementation of the Organisation for Economic Co-operation and Development’s Anti-Bribery Convention significantly increases audit fees charged to U.S. multinational firms with operations in corrupt foreign countries. The audit fee increase is larger for firms with operations in corrupt countries with strong enforcement of the Anti-Bribery Convention. In cross-sectional results consistent with expectations, we find that the impact intensifies when a firm has more extensive operations in corrupt countries; its internal control system has material weaknesses; and there is no recent FCPA enforcement in the industry or foreign country where the firm operates. We also document that audit delays rise after the Anti-Bribery Convention is instituted, reflecting that auditors exert more effort afterward. Taken together, our evidence implies that stricter enforcement of the FCPA through international cooperation in anti-corruption motivates auditors to become more sensitive to their clients’ foreign corruption risk.

Sobolev extension operators and Neumann eigenvalues

In this paper we apply estimates of the norms of Sobolev extension operators to the spectral estimates of the first non-trivial Neumann eigenvalue of the Laplace operator in non-convex extension domains. As a consequence we obtain a connection between resonant frequencies of free membranes and the smallest-circle problem(initially proposed by J. J. Sylvester in 1857).

Berth allocation recovery for container transshipment terminals

ABSTRACT In container terminals, operators normally form an initial plan for berth allocation before the arrival of incoming vessels. However, during the real operations, unforeseen incidents (e.g. delays, equipment breakdowns) happen frequently, which hinder the implementation of initial plans. In response to disruptions, terminal operators usually employ an experience-based strategy for berth allocation recovery. However, this practice may not work well in challenging situations, especially when extensive transshipment operations need to be conducted, and the berthing for mother and feeder vessels should be coordinated. This paper studies the disruption recovery problem for berth allocation in transshipment terminals, and develops decision support tools for terminal operators. A mixed integer linear programming model is established to adjust original berthing plan with the objective of minimizing recovery cost caused by deviations from the original plan. Quay crane assignment decision is also taken into account during disruption recovery. Transshipment connections between correlated feeder and mother vessels are also considered specifically in order to reduce the missing of transshipment connection opportunities. Squeaky Wheel Optimization heuristic is devised to find near-optimal solutions under large problem scales. Extensive computational experiments validate the effectiveness and the efficiency of designed method, and the results show practical benefit from incorporating transshipment consideration when rescheduling berth allocation.

Bilinear identities involving thek-plane transform and Fourier extension operators

AbstractWe prove certainL2(ℝn) bilinear estimates for Fourier extension operators associated to spheres and hyperboloids under the action of thek-plane transform. As the estimates areL2-based, they follow from bilinear identities: in particular, these are the analogues of a known identity for paraboloids, and may be seen as higher-dimensional versions of the classicalL2(ℝ2)-bilinear identity for Fourier extension operators associated to curves in ℝ2.