bluuebunny/crossref_metadata_2025 huggingface dataset:
Interleukins 4 and 13 modulate gene expression and promote proliferation of primary human tenocytes
Authors: Courneya Jean-Paul , Luzina Irina G , Zeller Cynthia B , Rasmussen Jeffrey F , Bocharov Alexander , Schon Lew C , Atamas Sergei P
Published: June 2010

Background

Tendon disorders (tendinopathies) pose serious biomedical and socioeconomic problems. Despite diverse treatment approaches, the best treatment strategy remains unclear. Surgery remains the last resort because of the associated morbidity and inconsistent outcomes. We hypothesized that, similar to fibroblasts in various organs, tendon fibroblasts (tenocytes) might be responsive to stimulation with interleukins (ILs), particularly IL-4 and IL-13. These two cytokines share sequence homology, receptor chains and functional effects, including stimulation of fibrogenesis. It is unknown whether tenocytes are responsive to stimulation with IL-4 or IL-13. If true, local use of these cytokines might be used to facilitate tendon repair in patients with tendinopathies or used for tendon tissue-engineering approaches to facilitate tenocyte growth on scaffolds in culture.

Results

Tendon tissues that would normally be discarded were obtained during reconstructive surgery procedures performed for clinical indications. Primary tenocytes were derived from Achilles, posterior tibial, flexor digitorum longus and flexor hallucis longus tendon tissue samples. Reverse transcriptase quantitative PCR (RT-qPCR) experiments revealed that mRNAs for the receptor (R) chains IL-4Rα, IL-13Rα1 and IL-13Rα2, but not the common γ-chain were present in all tested tendon tissues and in cultured tenocytes. Levels of IL-13R chain mRNAs were significantly higher than those of IL-4R mRNA. The cultures responded, in a dose-dependent fashion, to stimulation with recombinant human IL-4 or IL-13, by increasing proliferation rates 1.5 to 2.0-fold. The mRNA levels of 84 genes related to cell cycle regulation were measured by RT-qPCR after 6 h and 24 h of activation. The expression levels of several genes, notably CDK6 and CDKN2B changed more than twofold. In contrast to their effects on proliferation, stimulation with IL-4 or IL-13 had little if any effect on the levels of collagen mRNA or protein in cultured primary tenocytes. The mRNA levels of 84 other genes related to extracellular matrix and cell adhesion were also measured by RT-qPCR; expression of only five genes was consistently changed.

Conclusions

Stimulation with IL-4 or IL-13 could be used to facilitate tendon repair in vivo or to aid in tendon tissue engineering, through stimulation of tenocyte proliferation.
Risk factors for radiographic progression in psoriatic arthritis: subanalysis of the randomized controlled trial ADEPT
Authors: Gladman Dafna D , Mease Philip J , Choy Ernest HS , Ritchlin Christopher T , Perdok Renee J , Sasso Eric H
Published: June 2010

Introduction

To identify independent predictors of radiographic progression in psoriatic arthritis (PsA) for patients treated with adalimumab or placebo in the Adalimumab Effectiveness in PsA Trial (ADEPT).

Methods

Univariate analyses and multivariate linear regression analyses assessed risk for radiographic progression (change in modified total Sharp score, ΔmTSS > 0.5) from baseline to week 24 for C-reactive protein (CRP) and other baseline variables, and for 24-week time-averaged CRP (univariate analysis only). Subanalyses determined mean ΔmTSS for CRP subgroups. Analyses were post hoc, with observed data.

Results

One hundred and forty-four adalimumab-treated patients and 152 placebo-treated patients were assessed. Mean CRP was 64% lower by week 2 with adalimumab and essentially unchanged with placebo. Univariate analyses indicated that elevated CRP at baseline and time-averaged CRP were strongly associated with radiographic progression for placebo-treated patients but not for adalimumab-treated patients. Multivariate analysis confirmed that elevated baseline CRP was the only strong independent risk factor for radiographic progression (for CRP ≥1.0 mg/dl: odds ratio = 3.28, 95% confidence interval = 1.66 to 6.51, P < 0.001). Adalimumab treatment reduced risk of progression approximately fivefold. The difference between mean ΔmTSS for adalimumab versus placebo was greatest for patients with baseline CRP ≥2.0 mg/dl (-0.5 vs. 2.6).

Conclusions

Systemic inflammation in PsA, as indicated by elevated baseline CRP, was the only strong independent predictor of radiographic progression. This association was observed predominantly for placebo-treated patients. Adalimumab treatment substantially reduced the overall risk of radiographic progression, and provided greatest radiographic benefit for patients with the greatest CRP concentrations at baseline.

Trial Registration

Trial registration: NCT00195689.
Global fitness profiling of fission yeast deletion strains by barcode sequencing
Authors: Han Tian Xu , Xu Xing-Ya , Zhang Mei-Jun , Peng Xu , Du Li-Lin
Published: June 2010

A genome-wide deletion library is a powerful tool for probing gene functions and one has recently become available for the fission yeastSchizosaccharomyces pombe. Here we use deep sequencing to accurately characterize the barcode sequences in the deletion library, thus enabling the quantitative measurement of the fitness of fission yeast deletion strains by barcode sequencing.
N-Acylethanolamine Levels and Expression of Their Metabolizing Enzymes during Pregnancy
Authors: Fonseca B. M. , Correia-da-Silva G. , Taylor A. H. , Lam P. M. W. , Marczylo T. H. , Konje J. C. , Bell S. C. , Teixeira N. A.
Published: June 2010

Decidualization is essential for a successful pregnancy and is a tightly regulated process influenced by the local microenvironment. Lipid-based mediators, such as the endocannabinoid anandamide, and other compounds that have cannabimimetic actions may act on the decidua during early pregnancy. In this study, the levels of N-arachidonoylethanolamine (anandamide) and two other N-acylethanolamines, N-oleoylethanolamine and N-palmitoylethanolamine, were measured in rat plasma and maternal tissues between d 8 and 19 of pregnancy by ultraperformance liquid chromatography tandem mass spectrometry. The spatiotemporal expression of N-acylethanolamine metabolizing enzymes in implantation units were also determined by quantitative PCR, Western blot, and immunohistochemistry and shown to vary with gestation being mainly localized in decidual cells. The data also indicated that plasma and tissues levels of all three N-acylethanolamines fluctuate throughout pregnancy. Tissue levels of endocannabinoids did not correlate with plasma, suggesting that during pregnancy, maternal tissue levels of endocannabinoids are primarily regulated by in situ production and degradation to create endocannabinoid gradients conducive to successful pregnancy.
Regulation of the Hypothalamic-Pituitary-Adrenal Axis Circadian Rhythm by Endocannabinoids Is Sexually Diergic
Authors: Atkinson Helen C. , Leggett James D. , Wood Susan A. , Castrique Emma S. , Kershaw Yvonne M. , Lightman Stafford L.
Published: June 2010

We have examined the effects of acute administration of the cannabinoid receptor type 1 (CB1) antagonist AM251 on the rat hypothalamic-pituitary-adrenal (HPA) axis with respect to both gender and time of day. Blood samples were collected from conscious male and female rats every 5 min using an automated blood sampling system, and corticosterone concentrations were determined. In male rats, there was a distinct diurnal effect of AM251 with a greater activation of the HPA axis in the morning (diurnal trough) compared with the evening (diurnal peak). At both times of the day, circulating corticosterone concentrations were elevated for approximately 4 h after AM251 administration. In female rats, there was also diurnal variation in the activation of the HPA axis; however, these effects were not as profound as those in males. Corticosterone concentrations were only slightly elevated at the diurnal trough and for a shorter time period than in males (2 compared with 4 h). Moreover, there was no effect of AM251 on corticosterone concentrations when administered at the diurnal peak. Subsequent studies, only in males, in which both ACTH and corticosterone were measured, confirmed that the effects of AM251 on corticosterone were mediated by ACTH. Moreover, the elevation of both ACTH and corticosterone could be replicated using another CB1 antagonist, AM281. These data demonstrate that the extent and duration of HPA axis activation after CB1 blockade are clearly dependent on both gender and time of day.
Cholecystokinin Is Up-Regulated in Obese Mouse Islets and Expands β-Cell Mass by Increasing β-Cell Survival
Authors: Lavine Jeremy A. , Raess Philipp W. , Stapleton Donald S. , Rabaglia Mary E. , Suhonen Joshua I. , Schueler Kathryn L. , Koltes James E. , Dawson John A. , Yandell Brian S. , Samuelson Linda C. , Beinfeld Margery C. , Davis Dawn Belt , Hellerstein Marc K. , Keller Mark P. , Attie Alan D.
Published: June 2010

An absolute or functional deficit in β-cell mass is a key factor in the pathogenesis of diabetes. We model obesity-driven β-cell mass expansion by studying the diabetes-resistant C57BL/6-Leptinob/ob mouse. We previously reported that cholecystokinin (Cck) was the most up-regulated gene in obese pancreatic islets. We now show that islet cholecystokinin (CCK) is up-regulated 500-fold by obesity and expressed in both α- and β-cells. We bred a null Cck allele into the C57BL/6-Leptinob/ob background and investigated β-cell mass and metabolic parameters of Cck-deficient obese mice. Loss of CCK resulted in decreased islet size and reduced β-cell mass through increased β-cell death. CCK deficiency and decreased β-cell mass exacerbated fasting hyperglycemia and reduced hyperinsulinemia. We further investigated whether CCK can directly affect β-cell death in cell culture and isolated islets. CCK was able to directly reduce cytokine- and endoplasmic reticulum stress-induced cell death. In summary, CCK is up-regulated by islet cells during obesity and functions as a paracrine or autocrine factor to increase β-cell survival and expand β-cell mass to compensate for obesity-induced insulin resistance.
B56α/Protein Phosphatase 2A Inhibits Adipose Lipolysis in High-Fat Diet-Induced Obese Mice
Authors: Kinney Brice P. , Qiao Liping , LeVaugh Justin M. , Shao Jianhua
Published: June 2010

Lipolysis and lipogenesis are two opposite processes that control lipid storage in adipocytes. Impaired adipose lipolysis has been observed in both obese human subjects and animal models. This study investigated the mechanisms underlying impaired adipose lipolysis in a high-fat diet-induced obese (DIO) mouse model. DIO models were created using male C57BL/6 mice. Our results show that β3 adrenergic receptor-specific agonist BRL37344 induced adipose lipolysis was significantly blunted in DIO mice. The levels of Ser660 phosphorylation of hormone-sensitive lipase (HSL) were significantly decreased in the epididymal fat of DIO mice. However, protein levels of HSL, adipose triglyceride lipase and its coactivator comparative gene identification-58 were similar between DIO and control mice. It is known that upon lipolytic hormone stimulation, protein kinase A phosphorylates HSL Ser660 and activates HSL, whereas protein phosphatase 2A (PP2A) dephosphorylates and inactivates HSL. Interestingly, our study shows that high-fat feeding did not alter epididymal fat cAMP and protein kinase A protein levels but significantly increased the expression of the α-isoform of PP2A regulatory subunit B′ (B56α). To study the role of B56α in obesity-associated lipolytic defect, B56α was overexpressed or knocked down by adenovirus-mediated gene transduction in cultured 3T3-L1CARΔ1 adipocytes. Overexpression of B56α significantly decreased HSL Ser660 phosphorylation. In contrast, knocking down B56α increased hormone-stimulated HSL activation and lipolysis in mature 3T3-L1CARΔ1 adipocytes. These results strongly suggest that elevated B56α/PP2A inhibits HSL and lipolysis in white adipose tissue of DIO mice.
KISS1 Is Down-Regulated by 17β-Estradiol in MDA-MB-231 Cells through a Nonclassical Mechanism and Loss of Ribonucleic Acid Polymerase II Binding at the Proximal Promoter
Authors: Huijbregts Lukas , de Roux Nicolas
Published: June 2010

Kisspeptins are hypothalamic neuropeptides encoded by KISS1 and recently described as major regulators of GnRH release from hypothalamic neurons. Although 17β-estradiol (E2)-induced up-regulation of KISS1 expression has been documented in anteroventral periventricular nucleus neurons, E2 down-regulates KISS1 expression in arcuate nucleus neurons via the estrogen receptor α by unknown molecular mechanisms. Because KISS1 was initially described as a metastasis inhibitor, notably in breast tumors, we used the MDA-MB-231 breast cancer cell line, which expresses high levels of KISS1, to characterize the molecular mechanism underlying KISS1 regulation by E2. E2 rapidly down-regulated endogenous KISS1 in a stable ERα-expressing MDA-MB-231 cell line. Promoter analysis revealed that E2 down-regulation was determined by a short 93-bp sequence devoid of estrogen response element and Sp1 sites. E2 down-regulation persisted with an ERα that was unable to bind DNA and in the presence of histone deacetylase inhibitor. In the absence of E2, unliganded ERα and RNA polymerase II (RNAPII) were present on the proximal promoter. E2 stimulation induced recruitment of ERα and loss of RNAPII at the proximal promoter. Along the gene body, total RNAPII amounts were similar in E2-treated and untreated cells, whereas the active form was significantly less abundant in E2-treated cells. Thus, E2-induced down-regulation of KISS1 is mediated by a pathway combining RNAPII loss at the proximal promoter and modulation of active RNAPII along the gene body, which is a novel mechanism in the complex process of E2-induced repression of gene expression.
Estradiol Replacement Alters Expression of Genes Related to Neurotransmission and Immune Surveillance in the Frontal Cortex of Middle-Aged, Ovariectomized Rats
Authors: Sárvári Miklós , Kalló Imre , Hrabovszky Erik , Solymosi Norbert , Tóth Kinga , Likó István , Molnár Béla , Tihanyi Károly , Liposits Zsolt
Published: June 2010

Estradiol (E2) modulates a wide range of functions of the frontal cerebral cortex. From the onset of menopause, declining levels of E2 can cause cognitive disturbances and changes in behavior that can be counterbalanced by hormone replacement. To study the effect of E2 replacement on the cortical transcriptome in a rodent model with low serum E2 level, we treated middle-aged, ovariectomized rats with E2 or vehicle using osmotic minipumps for 4 wk. Six animals for each group were selected, and samples of their frontal cortex were subjected to expression profiling using oligonucleotide microarrays. The explored E2-regulated genes were related to neurotransmission (Adora2a, Cartpt, Drd1a, Drd2, Gjb2, Nts, and Tac1), immunity (C3, C4b, Cd74, Fcgr2b, Mpeg1, and RT1-Aw2), signal transduction (Igf2, Igfbp2, Igfbp6, Rgs9, and Sncg), transport (Abca1, Hba-a2, Slc13a3, and Slc22a8), extracellular matrix (Col1a2, Col3a1, Fmod, and Lum), and transcription (Irf7 and Nupr1). Seventy-four percent of the transcriptional changes identified by microarray were confirmed by quantitative real-time PCR. The genes identified by expression profiling indicated that chronic E2 replacement significantly altered the transcriptome of the frontal cortex. The genomic effects of E2 influenced dopaminergic and peptidergic neurotransmission, immune surveillance, adenosine and insulin-like growth factor signaling and transport processes, among other functions. Identification of these novel E2-regulated mechanisms highlights the wide range of genomic responses of the aging female frontal cerebral cortex subjected to hormone replacement. Some of the genomic effects identified in this study may underlie the beneficial effects of E2 on cognition, behavior, and neuroprotection.
An Antiinflammatory and Reactive Oxygen Species Suppressive Effects of an Extract of Polygonum Cuspidatum Containing Resveratrol
Authors: Ghanim Husam , Sia Chang Ling , Abuaysheh Sanaa , Korzeniewski Kelly , Patnaik Priyanka , Marumganti Anuritha , Chaudhuri Ajay , Dandona Paresh
Published: June 2010

Background: Resveratrol have been shown to exert an antiinflammatory and antiaging effects in vitro and in animal models.

Objective: The objective of the study was to investigate the effect of a Polygonum cuspidatum extract (PCE) containing resveratrol on oxidative and inflammatory stress in normal subjects.

Research Design and Methods: Two groups (10 each) of normal-weight healthy subjects were randomized to placebo or PCE containing 40 mg resveratrol daily for 6 wk. Fasting blood samples were obtained prior to and after treatment at 1, 3, and 6 wk. Mononuclear cells were prepared for reactive oxygen species generation, RNA isolation, nuclear extract, and total cell homogenate preparation. Indices of oxidative and inflammatory stress, suppressor of cytokine signaling-3, phosphotyrosine phosphatase-1B, jun-N-terminal kinase-1, and inhibitor of κB-kinase-β were measured by RT-PCR and Western blotting.

Results: The extract induced a significant reduction in reactive oxygen species generation, the expression of p47phox, intranuclear nuclear factor-κB binding, and the expression of jun-N-terminal kinase-1, inhibitor of κB-kinase-β, phosphotyrosine phosphatase-1B, and suppressor of cytokine signaling-3 in mononuclear cells when compared with the baseline and the placebo. PCE intake also suppressed plasma concentrations of TNF-α, IL-6, and C-reactive protein. There was no change in these indices in the control group given placebo.

Conclusions: The PCE-containing resveratrol has a comprehensive suppressive effect on oxidative and inflammatory stress.
Proper differentiation of photoreceptors and amacrine cells depends on a regulatory loop between NeuroD and Six6
Authors: Conte Ivan , Marco-Ferreres Raquel , Beccari Leonardo , Cisneros Elsa , Ruiz José María , Tabanera Noemí , Bovolenta Paola
Published: June 2010

Timely generation of distinct neural cell types in appropriate numbers is fundamental for the generation of a functional retina. In vertebrates, the transcription factor Six6 is initially expressed in multipotent retina progenitors and then becomes restricted to differentiated retinal ganglion and amacrine cells. How Six6 expression in the retina is controlled and what are its precise functions are still unclear. To address this issue, we used bioinformatic searches and transgenic approaches in medaka fish (Oryzias latipes) to characterise highly conserved regulatory enhancers responsible for Six6 expression. One of the enhancers drove gene expression in the differentiating and adult retina. A search for transcription factor binding sites, together with luciferase, ChIP assays and gain-of-function studies, indicated that NeuroD, a bHLH transcription factor, directly binds an ‘E-box’ sequence present in this enhancer and specifically regulates Six6 expression in the retina. NeuroD-induced Six6 overexpression in medaka embryos promoted unorganized retinal progenitor proliferation and, most notably, impaired photoreceptor differentiation, with no apparent changes in other retinal cell types. Conversely, Six6 gain- and loss-of-function changed NeuroD expression levels and altered the expression of the photoreceptor differentiation marker Rhodopsin. In addition, knockdown of Six6 interfered with amacrine cell generation. Together, these results indicate that Six6 and NeuroD control the expression of each other and their functions coordinate amacrine cell generation and photoreceptor terminal differentiation.
Adult pancreatic acinar cells give rise to ducts but not endocrine cells in response to growth factor signaling
Authors: Blaine Stacy A. , Ray Kevin C. , Anunobi Reginald , Gannon Maureen A. , Washington Mary K. , Means Anna L.
Published: June 2010

Studies in both humans and rodents have found that insulin+ cells appear within or near ducts of the adult pancreas, particularly following damage or disease, suggesting that these insulin+ cells arise de novo from ductal epithelium. We have found that insulin+ cells are continuous with duct cells in the epithelium that makes up the hyperplastic ducts of both chronic pancreatitis and pancreatic cancer in humans. Therefore, we tested the hypothesis that both hyperplastic ductal cells and their associated insulin+ cells arise from the same cell of origin. Using a mouse model that develops insulin+ cell-containing hyperplastic ducts in response to the growth factor TGFα, we performed genetic lineage tracing experiments to determine which cells gave rise to both hyperplastic ductal cells and duct-associated insulin+ cells. We found that hyperplastic ductal cells arose largely from acinar cells that changed their cell fate, or transdifferentiated, into ductal cells. However, insulin+ cells adjacent to acinar-derived ductal cells arose from pre-existing insulin+ cells, suggesting that islet endocrine cells can intercalate into hyperplastic ducts as they develop. We conclude that apparent pancreatic plasticity can result both from the ability of acinar cells to change fate and of endocrine cells to reorganize in association with duct structures.
MID1 and MID2 are required for Xenopus neural tube closure through the regulation of microtubule organization
Authors: Suzuki Makoto , Hara Yusuke , Takagi Chiyo , Yamamoto Takamasa S. , Ueno Naoto
Published: June 2010

Closure of the neural tube requires both the change and maintenance of cell shape. The change occurs mainly through two coordinated morphogenetic events: cell elongation and apical constriction. How cytoskeletal elements, including microtubules, are regulated in this process in vivo is largely unknown. Here, we show that neural tube closure in Xenopus depends on orthologs of two proteins: MID1, which is responsible for Opitz G/BBB syndrome in humans, and its paralog MID2. Depletion of the Xenopus MIDs (xMIDs) by morpholino-mediated knockdown disrupted epithelial morphology in the neural plate, leading to neural tube defects. In the xMID-depleted neural plate, the normal epithelial organization was perturbed without affecting neural fate. Furthermore, the xMID knockdown destabilized and caused the disorganization of microtubules, which are normally apicobasally polarized, accounting for the abnormal phenotypes. We also found that the xMIDs and their interacting protein Mig12 were coordinately required for microtubule stabilization during remodeling of the neural plate. Finally, we showed that the xMIDs are required for the formation of multiple epithelial organs. We propose that similar MID-governed mechanisms underlie the normal morphogenesis of epithelial tissues and organs, including the tissues affected in patients with Opitz G/BBB syndrome.
Book Reviews
Authors: Lev Benjamin
Published: June 2010

In Book Reviews, we review an extensive and diverse range of books. They cover theory and applications in operations research, statistics, management science, econometrics, mathematics, computers, and information systems. In addition, we include books in other fields that emphasize technical applications. However, we do not review software. To submit a book for review, please send it to me at the above address. Although we cannot review all books because of space limitations, we do list all books that we receive. We commission all book reviews and do not accept unsolicited reviews. To become a reviewer, please send me your name, address, and specific areas of expertise. We encourage readers to suggest books for review or to ask publishers to send copies of such books.

The authors or editors of books that we review in this issue are Jonathan L. Gross and H. Paul Williams.
Causes of the Decline of the Business School Management Science Course
Authors: Grossman Thomas A.
Published: June 2010

The business school management science course is suffering serious decline. The traditional model- and algorithm-based course fails to meet the needs of MBA programs and students. Poor student mathematical preparation is a reality, and is not an acceptable justification for poor teaching outcomes. Management science Ph.D.s are often poorly prepared to teach in a general management program, having more experience and interest in algorithms than management. The management science profession as a whole has focused its attention on algorithms and a narrow subset of management problems for which they are most applicable. In contrast, MBA's rarely encounter problems that are suitable for straightforward application of management science tools, living instead in a world where problems are ill-defined, data is scarce, time is short, politics is dominant, and rational “decision makers” are non-existent. The root cause of the profession's failure to address these issues seems to be (in Russell Ackoff's words) a habit of professional introversion that caused the profession to be uninterested in what MBA's really do on the job and how management science can help them.
Teaching Management Science with Spreadsheets: From Decision Models to Decision Support
Authors: Ragsdale Cliff T.
Published: June 2010

The 1990s were a decade of enormous change for management science (MS) educators. While the outlook at the beginning of the decade was somewhat bleak, the renaissance in MS education brought about by the use of spreadsheets as the primary delivery vehicle for quantitative modeling techniques has resulted in a much brighter future. This paper takes inventory of the current state of MS education and suggests some promising new directions in the area of decision support systems for MS educators to consider for the future.
Puzzle—Solving the Battleship Puzzle as an Integer Programming Problem
Authors: Meuffels W. J. M. , den Hertog D.
Published: June 2010

One's aim in solving logical puzzles is to find the solution by making use of several clues and restrictions. In this paper, we solve a logical puzzle, the Battleship puzzle, by integer programming. Moreover, two integer programming models (i.e., a cell-based model and a ship-based model) for the Battleship puzzle are compared based on their complexity and solution times. The ship-based model requires more preprocessing work before running the integer program than the cell-based model, but strongly outperforms the latter one. Finally, the models are used to check if a puzzle contains redundant information and to create a puzzle with a unique solution.
An In-Class Competition Introducing Inventory Management Concepts
Authors: Robb David J. , Johnson M. Eric , Silver Edward A.
Published: June 2010

Encouraging interest in inventory management necessitates that instructors overcome concerns that the subject is too abstract or conceptual. To aid in this process, we describe a competition engaging students in concepts, including demand estimation, demand uncertainty, and costs of inventory and shortages. The competition simulates a multi-item newsvendor problem employing participant-generated data. We present results from use of the exercise in multiple class settings over the past decade. A number of possible extensions of the basic competition are discussed. Data collection and analysis materials are available to interested readers.
Simpler Spreadsheet Simulation of Multi-Server Queues
Authors: Leong Thin-Yin
Published: June 2010

Process-driven spreadsheet queuing simulation provides a clear and intuitive approach for students in business modeling courses to learn about queue behavior. With basic spreadsheet skill, some guidance on the generation of random variates and simple assumptions like “service in arrival order,” it is not difficult to construct a single server spreadsheet simulation model. However to extend the model to multiple servers, add-ins, macros, or multiple templates (each for a given fixed number of servers) are needed. Hora [Hora, S. C. 2003. Spreadsheet modeling of the G/G/c queuing system without macros or add-ins. INFORMS Trans. Ed. 3(3), http://ite.pubs.informs.org/Vol3No3/Hora/ ] showed that array formulas can be used instead, to create the G/G/c spreadsheet model with parametrically adjustable number of servers. This is a great improvement, but array formulations are still inherently complex and therefore not easy for students to comprehend and apply. In this paper, I show that non-array formulations can achieve the same effect, effectively simplifying the model.
Incentives in New Product Development Projects and the Role of Target Costing
Authors: Mihm Jürgen
Published: June 2010

This paper investigates how self-optimizing engineers affect new product development (NPD) project outcomes and development times. A variety of widely used NPD project management approaches, including heavyweight project management, may allow or even encourage engineers to introduce late design changes and exhibit weak cost compliance, reducing the product's profit or competitiveness. Providing specifically designed incentives for individuals can eliminate such encouragement, and thus improve cost compliance and project timeliness. This paper discusses several practical incentive schemes, including profit-sharing contracts and component-level target costing. For many industrial projects, component-level target costing makes the most efficient use of available information to optimize project outcomes and reduce development times.
eBay's Crowded Evenings: Competition Neglect in Market Entry Decisions
Authors: Simonsohn Uri
Published: June 2010

Do firms neglect competition when making entry decisions? This paper addresses this question analyzing the time of day at which eBay sellers set their auctions to end. Consistent with competition neglect, it is found that (i) a disproportionate share of auctions end during peak bidding hours, (ii) such hours exhibit lower selling rates and prices, and (iii) peak listing is more prevalent among sellers likely to have chosen ending time strategically, suggesting disproportionate entry is a mistake driven by bounded rationality rather than mindlessness. The results highlight the importance for marketing researchers of assessing rather than assuming the rationality of firm behavior.
Optimal Flexibility Configurations in Newsvendor Networks: Going Beyond Chaining and Pairing
Authors: Bassamboo Achal , Randhawa Ramandeep S. , Van Mieghem Jan A.
Published: June 2010

We study the classical problem of capacity and flexible technology selection with a newsvendor network model of resource portfolio investment. The resources differ by their level of flexibility, where “level-k flexibility” refers to the ability to process k different product types. We present an exact set-theoretic methodology to analyze newsvendor networks with multiple products and parallel resources. This simple approach is sufficiently powerful to prove that (i) flexibility exhibits decreasing returns and (ii) the optimal portfolio will invest in at most two, adjacent levels of flexibility in symmetric systems, and to characterize (iii) the optimal flexibility configuration for asymmetric systems as well. The optimal flexibility configuration can serve as a theoretical performance benchmark for other configurations suggested in the literature. For example, although chaining is not optimal in our setting, the gap is small and the inclusion of scale economies quickly favors chaining over pairing. We also demonstrate how this methodology can be applied to other settings such as product substitution and queuing systems with parameter uncertainty.
Optimal Control and Equilibrium Behavior of Production-Inventory Systems
Authors: Wu Owen Q. , Chen Hong
Published: June 2010

The relationship between commodity inventory and short-term price variations has received considerable attention, but the understanding has been limited to single-stage cross-sectional relation. In this paper, we aim to deepen our understanding of the inventory–price relationship in two dimensions: across time and across production stages. We first examine an individual firm controlling production and two stages of inventory under uncertain input and output prices and operating costs. We next establish and characterize the rational expectations equilibrium for an economy in which competitive production firms link a raw material market and a finished goods market, with uncertain and price-sensitive supply and demand. We characterize the dynamics of inventory, market price, and gross margin based on theoretical analysis, simulation, and empirical evidence from the petroleum industry. We find that inventory fluctuations lag behind price variations, and the length of the lags depend on how far the inventory is from the source of the supply or demand shocks. We also find that shocks are both dampened and delayed when propagating through the production stages, and that shocks have a prolonged effect on inventories and prices at both stages.
Improving Supply Chain Performance and Managing Risk Under Weather-Related Demand Uncertainty
Authors: Chen Frank Youhua , Yano Candace Arai
Published: June 2010

We consider a manufacturer-retailer supply chain for a seasonal product whose demand is weather sensitive. The retailer orders from the manufacturer (supplier) prior to the selling season and then sells to the market. We examine how a manufacturer can structure a weather-linked rebate to improve his expected profit. The proposed class of rebate contracts offers several advantages over many other contract structures, including no required verification of leftover inventory and/or markdown amounts, and no adverse effect on sales effort by the retailer. We provide a thorough analysis of the manufacturer's and retailer's decisions in this context. We show that the weather-linked rebate can take many different forms, and this flexibility allows the supplier to design contracts that are Pareto improving and/or limit his risk in offering the contract and the retailer's risk in accepting it. For weather rebates with certain characteristics, the manufacturer can fully hedge his risks of offering a weather rebate by paying a risk premium; we show how this can be accomplished. We also show that the basic structural results extend to settings in which the two parties would like to limit their risk.
Uso de sistema GPR (Ground Penetring Radar) na avaliação de atributos de um solo sob plantio de cana-de-açúcar
Authors: Cezar Everson , Nanni Marcos Rafael , Chicati Marcelo Luiz , Fabrio Felipe Derbocio , Hata Fernando Teruhiko , Oliveira Roney Berty de
Published: June 2010

O GPR utiliza técnica indireta para investigação das estruturas de subsuperfície, sendo caracterizado como método não-invasivo, o qual permite extrair informações ao longo do perfil de solo sem perfurar, sondar ou escavar. Este trabalho teve o objetivo de avaliar a utilização do GPR no estabelecimento de atributos físicos do solo em área de cultivo com cana-de-açúcar, além de estabelecer sua correlação com o método do cilindro volumétrico. A área de estudo está localizada no município de Bom Sucesso - PR, sendo utilizada com cultura da cana há mais de 20 anos. Foram obtidas amostras de solos indeformadas com cilindro volumétrico nas profundidades de 0-0,1, 0,1-0,2, 0,2-0,3, 0,3-0,4 e 0,4-0,5 m, ao longo de três transeptos paralelos, sendo o central referente à linha de plantio (transepto 2) e os outros dois correspondentes às entrelinhas laterais (transeptos 1 e 3). Os valores de densidade e porosidade total, obtidos por meio das amostras físicas, foram inicialmente interpretados para verificar o estado do solo nas linhas e nas entrelinhas de cana, nas cinco profundidades. Posteriormente, foram correlacionados com os valores das constantes dielétricas (K) adquiridos pelo georradar, porém apenas para a camada de 0,4-0,5 m, uma vez que as camadas superficiais até a profundidade de 0,4 m não puderam ser avaliadas devido às limitações técnicas do equipamento, aliadas às condições físicas e químicas do solo, que acabaram por prejudicar as reflexões. A densidade mostrou-se menor nas linhas, quando comparada às entrelinhas, para as camadas de 0-0,1 e 0,2-0,3 m. A porosidade total foi menor nas entrelinhas do que nas linhas na camada de 0-0,1 m. Os valores de K foram maiores nas linhas, onde a umidade e a porosidade total foram maiores, e menores nas entrelinhas, onde as densidades encontravam se próximas ao limite crítico. A correlação de K com a densidade e porosidade total não foi significativa. Pequenas modificações na porosidade do solo em função do aumento da densidade foram suficientes para diminuir o valor de K nas entrelinhas, devido à redução na quantidade de água nos poros. Esse fato pode ser confirmado pela correlação de K com a umidade. Assim, pode-se dizer que o georradar foi extremamente sensível à variação de umidade no solo, apresentando melhores resultados para esta variável do que para a densidade e porosidade total determinada por meio do cilindro volumétrico.
Suscetibilidade magnética do horizonte B de solos do Estado do Paraná
Authors: Silva Alceu Rodrigues da , Souza Junior Ivan Granemann de , Costa Antonio Carlos Saraiva da
Published: June 2010

Os minerais ferrimagnéticos maghemita (γFe2O3) e magnetita (Fe3O4) possuem alta relação com a disponibilidade de cátions metálicos e com a capacidade do solo em adsorver ânions como o fosfato. Uma percentagem expressiva dos solos brasileiros apresenta magnetização espontânea. No Estado do Paraná essa área corresponde a aproximadamente 50 %. A determinação da suscetibilidade magnética por unidade de massa (ΧBF) é o método mais simples de identificar a presença e quantificar esses minerais nos solos. A BF é uma técnica rápida, barata, não destrutiva e de boa reprodutibilidade, que pode ser utilizada como critério nos estudos pedogenéticos em que os minerais ferrimagnéticos estão presentes. O objetivo deste trabalho foi verificar a influência do material de origem nos valores de ΧBF da terra fina seca ao ar (TFSA) de amostras do horizonte B de solos do Paraná. As amostras foram coletadas em todo o Estado, num total de 45 pontos. Na TFSA foram determinados os valores de BF e da porcentagem da frequência dependente da suscetibilidade magnética (ΧFD). Os valores de suscetibilidade magnética dos solos formados sobre rochas eruptivas básicas foram significativamente maiores (1.000 a 7.800 x 10-8 m³ kg-1) que os encontrados em solos formados sobre rochas metamórficas e sedimentares (menores do que 500 x 10-8 m³ kg-1), demonstrando a influência do material de origem na presença de minerais ferrimagnéticos. Os valores de ΧFD indicaram a presenca de partículas superparamagnéticas (maghemita) na maioria dos solos paranaenses.
Isolation and characterization of two plant growth-promoting bacteria from the rhizoplane of a legume (Lupinus albescens) in sandy soil
Authors: Giongo Adriana , Beneduzi Anelise , Ambrosini Adriana , Vargas Luciano Kayser , Stroschein Marcos Roberto , Eltz Flávio Luiz , Bodanese-Zanettini Maria Helena , Passaglia Luciane Maria Pereira
Published: June 2010

Two bacterial strains that amplified part of the nifH gene, RP1p and RP2p, belonging to the genus Enterobacter and Serratia, were isolated from the rhizoplane of Lupinus albescens. These bacteria are Gram-negative, rod-shaped, motile, facultative anaerobic, and fast-growing; the colonies reach diameters of 3-4 mm within 24 h of incubation at 28 ºC. The bacteria were also able to grow at temperatures as high as 40 ºC, in the presence of high (2-3 % w/v) NaCl concentrations and pH 4 -10. Strain RP1p was able to utilize 10 of 14 C sources, while RP2p utilized nine. The isolates produced siderophores and indolic compounds, but none of them was able to solubilize phosphate. Inoculation of L. albescens with RP1p and RP2p strains resulted in a significant increase in plant dry matter, indicating the plant-growth-promoting abilities of these bacteria.
Nitrate and ammonium in soil solution in tobacco management systems
Authors: Kaiser Douglas Rodrigo , Reinert Dalvan José , Reichert José Miguel , Streck Carlos Arnoldo , Pellegrini André
Published: June 2010

Tobacco farmers of southern Brazil use high levels of fertilizers, without considering soil and environmental attributes, posing great risk to water resources degradation. The objective of this study was to monitor nitrate and ammonium concentrations in the soil solution of an Entisol in and below the root zone of tobacco under conventional tillage (CT), minimum tillage (MT) and no-tillage (NT). The study was conducted in the small-watershed Arroio Lino, in Agudo, State of Rio Grande do Sul, Brazil. A base fertilization of 850 kg ha-1 of 10-18-24 and topdressing of 400 kg ha-1 of 14-0-14 NPK fertilizer were applied. The soil solution was sampled during the crop cycle with a tension lysimeter equipped with a porous ceramic cup. Ammonium and nitrate concentrations were analyzed by the distillation and titration method. Nitrate concentrations, ranging from 8 to 226 mg L-1, were highest after initial fertilization and decreased during the crop cycle. The average nitrate (N-NO3-) concentration in the root zone was 75 in NT, 95 in MT, and 49 mg L-1 in CT. Below the root zone, the average nitrate concentration was 58 under NT, 108 under MT and 36 mg L-1 under CT. The nitrate and ammonium concentrations did not differ significantly in the management systems. However, the nitrate concentrations measured represent a contamination risk to groundwater of the watershed. The ammonium concentration (N-NH4+) decreased over time in all management systems, possibly as a result of the nitrification process and root uptake of part of the ammonium by the growing plants.
Variabilidade espacial dos teores de macronutrientes em latossolos sob sistema plantio direto
Authors: Zanão Júnior Luiz Antônio , Lana Regina Maria Quintão , Guimarães Ednaldo Carvalho , Pereira Josefa Monteiro de Araújo
Published: June 2010

A eficácia dos planos de amostragem do solo pode ser aumentada se for conhecida e considerada a variabilidade espacial de seus atributos, e, para isso, devem ser estudados os fatores que a determinam. O objetivo deste trabalho foi avaliar a variabilidade espacial dos teores de macronutrientes P, K, Ca, Mg e S em dois Latossolos, um muito argiloso e outro de textura média, cultivados com manejo semelhante, há oito anos sob sistema plantio direto. A coleta das amostras do solo foi realizada em intervalos regulares de 50 m, totalizando 121 pontos, em duas camadas (0-10 e 10-20 cm). Os dados foram avaliados por estatística descritiva e geoestatística, com base no ajuste de semivariogramas. Verificou-se que a dependência espacial varia conforme o elemento, a textura do solo e a profundidade de coleta da amostra. Assim, o Latossolo de textura média, de maneira geral, apresentou maior variabilidade espacial para os teores dos nutrientes em relação ao de textura muito argilosa. A camada de 0-10 cm, nos dois Latossolos, proporcionou maior variabilidade espacial para os teores dos nutrientes avaliados. A análise de dependência espacial mostrou que, nos dois solos e nas duas camadas, a maioria dos nutrientes estudados apresentou moderada correlação espacial. Os modelos de semivariogramas ajustados foram o exponencial e o esférico, sendo o primeiro em maior quantidade. Maiores teores de todos os macronutrientes avaliados foram verificados nos primeiros 10 cm do solo. Os valores de alcance da dependência espacial foram menores no Latossolo de textura média, variando de 9 a 29 m; no de textura muito argilosa eles variaram de 31 a 399 m. Se for adotada a geoestatística no esquema de amostragem, o número de amostras a serem coletadas será menor no Latossolo de textura muito argilosa, devido aos maiores valores do alcance apresentados por todas as variáveis.
Gesso agrícola e rendimento de grãos de soja na região do sudoeste de Goiás
Authors: Neis Lucimeire , Paulino Helder Barbosa , Souza Edicarlos Damacena de , Reis Edésio Fialho dos , Pinto Flávio Araújo
Published: June 2010

O revolvimento de áreas em plantio direto (PD) há vários anos e o uso de gesso agrícola são práticas observadas entre os produtores na região do sudoeste de Goiás. Este trabalho foi realizado com o objetivo de avaliar o efeito da aplicação de doses de gesso agrícola (0, 1, 2, 4 e 6 Mg ha-1) em alguns atributos químicos em profundidade no solo e no rendimento de grãos de soja em plantio direto com revolvimento (PDR) e sem revolvimento (PDS). O delineamento foi em blocos completos ao acaso, em esquema de parcelas subsubdivididas, com quatro repetições. A área vinha sendo conduzida há vários anos em PD, em um Latossolo Vermelho-Amarelo distrófico textura argilosa, no sudoeste goiano, com os teores de Ca2+, Mg2+, K+, sulfato e CTC efetiva sendo determinados nas camadas de 0-5, 5- 10, 10-20 e 20-40 cm. Observou-se que no PDS a maior concentração dos cátions e do sulfato ocorreu na camada de 0-5 cm, enquanto no PDR o sulfato se concentrou na de 20-40 cm. O maior rendimento de grãos de soja ocorreu no PDS, porém não houve influência das doses de gesso.
Postharvest nitrous oxide emissions from a subtropical oxisol as influenced by summer crop residues and their management
Authors: Escobar Luisa Fernanda , Amado Telmo Jorge Carneiro , Bayer Cimélio , Chavez Luis Fernando , Zanatta Josiléia Acordi , Fiorin Jackson Ernani
Published: June 2010

Nitrous oxide (N2O) is the most important non-CO2 greenhouse gas and soil management systems should be evaluated for their N2O mitigation potential. This research evaluated a long-term (22 years) experiment testing the effect of soil management systems on N2O emissions in the postharvest period (autumn) from a subtropical Rhodic Hapludox at the research center FUNDACEP, in Cruz Alta, state of Rio Grande do Sul. Three treatments were evaluated, one under conventional tillage with soybean residues (CTsoybean) and two under no-tillage with soybean (NTsoybean) and maize residues (NTmaize). N2O emissions were measured eight times within 24 days (May 2007) using closed static chambers. Gas flows were obtained based on the relations between gas concentrations in the chamber at regular intervals (0, 15, 30, 45 min) analyzed by gas chromatography. After soybean harvest, accumulated N2O emissions in the period were approximately three times higher in the untilled soil (164 mg m-2 N) than under CT (51 mg m-2 N), with a short-lived N2O peak of 670 mg m-2 h-1 N. In contrast, soil N2O emissions in NT were lower after maize than after soybean, with a N2O peak of 127 g m-2 h-1 N. The multivariate analysis of N2O fluxes and soil variables, which were determined simultaneously with air sampling, demonstrated that the main driving variables of soil N2O emissions were soil microbial activity, temperature, water-filled pore space, and NO3- content. To replace soybean monoculture, crop rotation including maize must be considered as a strategy to decrease soil N2O emissions from NT soils in Southern Brazil in a Autumn.
Influência do manejo do solo nas propriedades químicas e físicas em topossequência na bacia do rio Araguaia, Estado do Tocantins
Authors: Faria Ana Flávia Gouveia de , Santos Antonio Clementino dos , Santos Thiago Martins dos , Batistella Filho Felipe
Published: June 2010

A conversão do Cerrado nativo em áreas de exploração agrícola pode modificar os processos de decomposição e síntese da matéria orgânica do solo e, assim, na disponibilidade de nutrientes. Objetivou-se avaliar as propriedades químicas e físicas do solo em topossequência caracterizada por apresentar uso com pastagem cultivada com Brachiaria brizantha ao lado do Cerrado nativo, na camada de 0- 15 cm de profundidade. O estudo foi realizado no município de Colmeia, Estado do Tocantins. Foram determinados 10 pontos de coleta (cinco para Cerrado nativo e cinco para pasto) para cada posição do relevo (topo, encosta e pedimento); em cada ponto amostral, foram coletados solos em três profundidades (0-5, 5-10 e 10- 15 cm), totalizando 90 amostras. Foram realizadas as seguintes análises químicas e físicas: C orgânico, P, K+, Ca2+, Mg2+, H + Al, pH e granulometria. O C orgânico não apresentou diferença (p > 0,05) entre os valores encontrados no Cerrado nativo e pastagem e as posições do relevo avaliadas. A conversão de Cerrado nativo para uso agropecuário reduziu os teores de P. Os teores de K trocável não foram alterados pela retirada da cobertura vegetal original. Observou-se aumento dos teores de areia quando se passou da meia-encosta para o pedimento.