Valid Inequalities and Facets of the Capacitated Plant Location Problem

Recently, several successful applications of strong cutting plane methods to combinatorial optimization problems have renewed interest in cutting plane methods, and polyhedral characterizations, of integer programming problems.In this paper, we investigate the polyhedral structure of the capacitated plant location problem. Our purpose is to identify facets and valid inequalities for a wide range of capacitated fixed charge problems that contain this prototype problem as a substructure.The first part of the paper introduces a family of facets for a version of the capacitated plant location problem with constant capacity K for all plants. These facet inequalities depend on K and thus differ fundamentally from the valid inequalities for the uncapacitated version of the problem. We also introduce a second formulation for a model with indivisible customer demand and show that it is equivalent to a vertex packing problem on a derived graph. We identify facets and valid inequalities for this version of the problem by applying known results for the vertex packing polytope

Routing in Point-to-Point Delivery Systems

This paper was also printed as a Working Paper at the Yale School of Organization and Management, Series B, No. 103.We develop an optimization-based approach for a point-to-point route planning problem that arises in many large scale delivery systems(for example, less-than-truckload freight, rail, mail and package delivery, communications). In these settings, a firm which must ship goods between many origin and destination pairs on a network needs to specify a route for each origin-destination pair so as to minimize transportation costs and/or transit times. Typically, the cost structure is very complicated. The approach discussed in this paper exploits the structure of the problem to decompose it into two smaller subproblems, each amenable to solution by a combination of optimization and heuristic techniques. One subproblem is an 'assignment' problem with capacity constraints. The other subproblem is a mixed-integer multicommodity flow problem. We propose solution methods based on Lagrangian relaxation for each subproblem. Computational results with these methods and with a heuristic procedure for the multicommodity flow problem on a problem met in practice are encouraging and suggest that mathematical programming methods can be successfully applied to large-scale problems in delivery systems planning and other problems in logistical system design

Facets and Algorithms for Capacitated Lot Sizing

The dynamic economic lot sizing model, which lies at the core of numerous production planning applications, is one of the most highly studied models in all of operations research. And yet, capacitated multi-item versions of this problem remain computationally elusive. We study the polyhedral structure of an integer programming formulation of a single-item capacitated version of this problem, and use these results to develop solution methods for multi-item applications. In particular, we introduce a set of valid inequalities for the problem and show that they define facets of the underlying integer programming polyhedron. Computational results on several single and multiple product examples show that these inequalities can be used quite effectively to develop an efficient cutting plane/branch and bound procedure. Moreover, our results show that in many instances adding certain of these inequalities a priori to the problem formulation, and avoiding the generation of cutting planes, can be equally effective

Development and Preliminary Validation of an Equine Brief Pain Inventory for Owner Assessment of Chronic Pain Due to Osteoarthritis in Horses

An owner-completed questionnaire was designed to monitor the level of chronic pain and impact on quality of life in horses with osteoarthritis (OA). A standardized approach to develop and validate subjective-state scales for clinical use was followed. Scale items were generated through literature review, focus group meetings, and expert panel evaluation. The draft tool was tested for reading level and language ambiguity and piloted in 25 owners/caregivers of horses with osteo-arthritis, with factor analysis performed on responses. The resulting revised questionnaire is cur-rently undergoing validation in a larger sample population of 60 OA and 20 sound control horses. In the pilot group, 21 people (84%) found the questionnaire easy to complete and 22 people (88%) found it useful. It could be completed within 5 min by all participants. Readability scores (Flesch Reading Ease Score, Flesch–Kincaid grade level, SMOG index) indicated an English language reading level comparable to that of 6th to 7th grade in the U.S. system (age 11–12 years). Cronbach’s alpha of all items in the tool was 0.957, indicating excellent inter-item correlation. In-terim analysis for 23 OA horses from the sample population showed good test–retest reliability and higher scores compared to 5 control horses. Full validation must be completed for the in-strument to be used in clinical practice

Lipaza iz plijesni Mucor griseocyanus: proizvodnja, karakterizacija i istraživanje nekih katalitičkih svojstava imobiliziranog enzima

The aim of this work is to study the production of extracellular lipase by Mucor griseocyanus 55.1.1 strain on different substrates in order to select the ideal one for lipase synthesis. The carbon sources used were: olive oil, glycerol, coconut oil, sunflower oil, glucose, starch and sucrose. The obtained results indicate that the synthesis of the enzyme was possible in the presence of all substrates. Lipase activities in the range of 0.04 to 0.1 IU/mL were obtained. It was found that the most suitable carbon source for the production of the enzyme was a combination of coconut oil and sucrose at 0.5 and 1.5 % (m/V), respectively, and the level of activity reached under this condition was 0.113 IU/mL. The optimum pH and temperature for enzymatic extract activities were identified in a pH range of 4 to 6 and at a temperature of 60 °C. Enzymatic extract was stable for a period of 5 h in neutral and weakly acidic media (pH=6) at moderate temperatures between 20 and 40 °C. Studies on the catalytic properties (stereoselectivity and enantioselectivity) of the immobilized lipase using the esters of methyl phenyl glycinic and (R,S)-methyl mandelic acid showed excellent properties of the enzyme compared to commercial lipases tested. M. griseocyanus lipase exhibited a greater stereoselectivity towards the R-isomer of methyl phenyl glycinic acid ester. However, with the esters of methyl mandelic acid, the enzyme showed a certain preference toward the S-isomer and it was hydrolysed 20 times faster than the R-isomer.Svrha je ovoga rada bila proučiti proizvodnju ekstracelularne lipaze iz soja Mucor griseocyanus 55.1.1. na raznim podlogama radi odabira najboljeg načina sinteze lipaze. Upotrijebljeni su ovi izvori ugljika: maslinovo ulje, glicerol, kokosovo i suncokretovo ulje, te škrob i saharoza. Rezultati su pokazali da se sinteza enzima odvijala na svim podlogama, te da je postignuta aktivnost lipaze u rasponu od 0,04 do 0,1 IU/mL. Utvrđeno je da su najbolji rezultati dobiveni s podlogom koja sadržava 0,5 % (m/V) kokosova ulja i 1,5 % (m/V) saharoze, pri čemu je aktivnost enzima iznosila 0,113 IU/mL. Optimalna pH-vrijednost bila je od 4 do 6, a temperatura 60 ºC. Ekstrakt enzima bio je stabilan tijekom 5 sati u neutralnoj ili slabo kiseloj sredini (pH=6), pri temperaturama od 20 do 40 ºC. Istraživanjem katalitičkih svojstava (stereoselektivnosti i enantioselektivnosti) imobilizirane lipaze pomoću metilfenilnog estera glicinske kiseline i (R,S)-metilnog estera bademove kiseline dokazana su odlična svojstva tog enzima u usporedbi s komercijalnim lipazama. Lipaza iz plijesni M. griseocyanus ima veću stereoselektivnost prema R-oblicima metilfenilnog estera glicinske kiseline i S-izomeru metilnog estera bademove kiseline (kojeg hidrolizira 20 puta brže od R-izomera)

HAWAIIAN SKIRT controls size and floral organ number by modulating CUC1 and CUC2 expression

The Arabidopsis thaliana F-box gene HAWAIIAN SKIRT (HWS) affects organ growth and the timing of floral organ abscission. The loss-of-function hws-1 mutant exhibits fused sepals and increased organ size. To understand the molecular mechanisms of HWS during plant development, we mutagenized hws-1 seeds with ethylmethylsulphonate (EMS) and screened for mutations suppressing hws-1 associated phenotypes. We isolated the shs1/hws-1 (suppressor of hws-1) mutant in which hws-1 sepal fusion phenotype was suppressed. The shs1/hws-1 mutant carries a G→A nucleotide substitution in the MIR164 binding site of CUP-SHAPED COTYLEDON 1 (CUC1) mRNA. CUC1 and CUP-SHAPED COTYLEDON 2 (CUC2) transcript levels were altered in shs1, renamed cuc1-1D, and in hws-1 mutant. Genetic interaction analyses using single, double and triple mutants of cuc1-1D, cuc2-1D (a CUC2 mutant similar to cuc1-1D), and hws-1, demonstrate that HWS, CUC1 and CUC2 act together to control floral organ number. Loss of function of HWS is associated with larger petal size due to alterations in cell proliferation and mitotic growth, a role shared with the CUC1 gene

HAWAIIAN SKIRT, and F-box gene from Arabidopsis, is a new player in the microRNA pathway

F-box proteins belong to a multi-protein E3 ubiquitin ligase complex (SCF) that target proteins for degradation via the proteasome.We demonstrated that HAWAIIAN SKIRT(HWS), an Arabidopsis ubiquitin protein ligase (SCFHWS), regulates organ growth, flower development and timing of abscission. Mutants of this gene (hws-1) are pleiotropic and the most obvious phenotype is the fusion of its floral organs, a phenotype shared with the cuc1/cuc2 double mutants and over-expressing lines of MIR164B. To understand the molecular mechanisms of HWS during plant development, an ethylmethylsulphonate mutagenized population of hws-1 seeds was generated and screened for mutations suppressing the hws-1 sepal fusion. We isolated shs-1/hws-1, shs-2/hws-1, and shs-3/hws-1, (suppressor of hws-1) mutants. Mapping analyses shown that shs1 is mutated in the miRNA164 binding site of CUPSHAPED COTYLEDON1 (CUC1) mRNA; while shs-2 and shs-3 are novel alleles of the plant homolog of Exporting-5 HASTY (HST), known to be important in miRNA biogenesis, function and transport. Consequently, we renamed them cuc1-1D, hst23 and hst24, respectively. We demonstrated that transcript levels of CUC1 and CUPSHAPED COTYLEDON 2 (CUC2), and MIR164 change in cuc1-1D and in hws-1 mutants; analyses revealed a role for HWS in cell proliferation and control of floral organ number. Additional genetic crosses between hws-1 and mutant lines for genes in the miRNA pathway were performed and double mutants obtained shown restoration of the hws-1 sepal fusion phenotype. Our data propose HWS as a new regulator in miRNA pathway and reveal a role for HWS to control floral organ number and cell proliferation

Production of Extracellular Lipase from Aspergillus niger by Solid-State Fermentation

Proizvodnja lipaze u soju plijesni Aspergillus niger J-1 ispitana je submerznim uzgojem i površinskim uzgojem na čvrstoj podlozi od pšeničnih posija. Provedeno je optimiranje podloge za oba postupka uzgoja. Maksimalna aktivnost lipaze od 1,46 IU/mL postignuta je submerznim uzgojem u podlozi s 2 % glukoze i 2 % maslinova ulja pri 1 vvm i 450 m-1. Medutim, 9,14 IU/g suhe tvari ekvivalentne 4,8 IU/mL aktivnosti lipaze postignuto je površinskim uzgojem na čvrstoj podlozi s 0,75 % amonijeva sulfata i 0,34 % uree. Optimalni pH i temperatura za aktivnost enzima bili su pH=6 i 40 °C. Enzim je pokazao 80 % od početne aktivnosti u neutralnom i blago kiselom mediju i pri temperaturi od 20 i 30 °C tijekom 24 sata.Lipase production in Aspergillus niger J-1 was tested using both submerged fermentation (SmF) and solid-state fermentation (SSF) on a mineral culture medium and wheat bran, respectively. The optimization of the culture medium was carried out for both SmF and SSF. The maximum lipase activity, 1.46 IU/mL, was obtained during the submerged fermentation in a medium containing glucose at 2 % and olive oil at 2 % under conditions of 1 vvm and 450 m–1. However, 9.14 IU/g of dry solid substrate equivalent to 4.8 IU/mL of lipase activity was reached using solid-state fermentation process with a medium containing 0.75 % of ammonium sulphate and 0.34 % of urea. The optimum pH and temperature for enzymatic activity were pH=6 and 40 °C, respectively. The enzyme also exhibited 80 % of its initial activity in neutral and mildly acid media and at temperatures between 20 and 30 °C for a period of 24 hours

Laparoscopic vs. open adrenalectomy: perioperative data and survival analysis in 70 dogs with an adrenal tumor

Adrenalectomy is the treatment of choice in case of functional adrenal tumors and malignant adrenal incidentalomas. Laparoscopic adrenalectomy (LA) in dogs has gained popularity in recent years, however, clinical studies on large patient populations are scarce. This retrospective study describes perioperative and recurrence data, survival, and prognostic factors in 70 dogs that underwent LA or open adrenalectomy (OA) in our hospital between 2008 and 2022. Diagnosis was based on history, clinical signs, endocrine function tests and advanced diagnostic imaging. Laparoscopic adrenalectomy was performed in 42 dogs (n = 27 naturally occurring hypercortisolism, n = 4 pheochromocytoma, n = 1 pheochromocytoma with concurrent hypercortisolism, n = 10 incidentaloma) and OA in 28 dogs (n = 22 hypercortisolism, n = 3 pheochromocytoma, n = 3 incidentaloma). Bilateral adrenalectomy was performed in 8/70 dogs. Surgical duration of LA and OA did not differ significantly in unilateral and bilateral procedures (P = 0.108 and P = 0.101, respectively). Systemic hypertension occurred in 7/41 and 1/28 dogs during LA and OA, respectively (P = 0.130). Hypotension occurred in 2/41 and 4/28 dogs during LA and OA, respectively (P = 0.214). A total of 40/42 dogs in the LA group and 27/28 in the OA group survived to discharge (P = 0.810). Mean hospital stay was significantly shorter (P = 0.006) after LA (1.5 days, range 1–3) than after OA (2.2 days, range 1–4). No significant differences were demonstrated between LA and OA groups in recurrence of adrenal-dependent endocrine disease (P = 0.332), disease-free period (P = 0.733) and survival time (P = 0.353). The disease-specific 1-, 2- and 3-year survival rates were 95, 89, and 89% after LA and 92, 88, and 81% after OA. Tumor size was significantly associated with the occurrence of a recurrence. In addition, tumor size had a negative effect on the disease-free period and survival time. This study shows a favorable outcome of both LA and OA in dogs. Based on low perioperative complication rate, short hospitalization time and long-term outcomes comparable to OA in selected cases, the less invasive laparoscopic approach is considered the preferred technique