318,638 research outputs found
A Structural Econometric Model of Consumer Demand at Pick-Your-Own Fruit Operations
No full textThis paper develops a fully structural econometric consumer demand model for goods which have time and monetary costs, and where time spent obtaining the goods also enters into the utility function. The model is used to analyze customers' decision to buy pick-your-own versus pre-harvested fruit at North Carolina pick-your-own fruit operations. The empirical application distinguishes the double effect of time as a resource constraint and also providing utility. Elasticity estimates show that strawberries sold at pick-your-own operations are price elastic, with pick-your-own fruit being less price elastic than pre-harvested fruit.Consumer/Household Economics,
A behavioral view of Nevanlinna-Pick interpolation
No full textThe classical Nevanlinna-Pick (NP) interpolation problem is about finding a rational function that satisfies given interpolation conditions, along with a norm condition. In this paper we address the NP problem using concepts from behavioral systems theory and quadratic differential forms (QDFs). The NP problem is solved using a certain “dualization of data”. We address system theoretic motivations for this dualization and the advantages gained in this process. Finally, we address the problem of constructing interpolating functions that satisfy a “frequency dependent” norm condition
Performance Approximation and Design of Pick-and-Pass Order Picking Systems
No full textIn this paper, we discuss an approximation method based on G/G/m queuing network modeling using Whitt’s (1983) queuing network analyzer to analyze pick-and-pass order picking systems. The objective of this approximation method is to provide an instrument for obtaining rapid performance estimates (such as order lead time and station utilization) of the order picking system. The pick-and-pass system is decomposed into conveyor pieces and pick stations. Conveyor pieces have a constant processing time, whereas the service times at a pick station depend on the number of order lines in the order to be picked at the station, the storage policy at the station, and the working methods. Our approximation method appears to be sufficiently accurate for practical purposes. It can be used to rapidly evaluate the effects of the storage methods in pick stations, the number of order pickers at stations, the size of pick stations, the arrival process of customer orders, and the impact of batching and splitting orders on system performance.simulation;warehousing;order picking;queuing network;pick-and-pass
Order batching in multi-server pick-and-sort warehouses.
No full textIn many warehouses, customer orders are batched to profit from a reduction in the order picking effort. This reduction has to be offset against an increase in sorting effort. This paper studies the impact of the order batching policy on average customer order throughput time, in warehouses where the picking and sorting functions are executed separately by either a single operator or multiple parallel operators. We present a throughput time estimation model based on Whitt's queuing network approach, assuming that the number of order lines per customer order follows a discrete probability distribution and that the warehouse uses a random storage strategy. We show that the model is adequate in approximating the optimal pick batch size, minimizing average customer order throughput time. Next, we use the model to explore the different factors influencing optimal batch size, the optimal allocation of workers to picking and sorting, and the impact of different order picking strategies such as sort-while-pick (SWP) versus pick-and-sort (PAS)Order batching; Order picking and sorting; Queueing; Warehousing;
Aspectes moleculars de dues malalties de transport lisosòmic: la cistinosi i la malaltia de Niemann-Pick tipus C
No full text[cat] La cistinosi i la malaltia de Niemann-Pick tipus C (NPC) són dues patologies hereditàries monogèniques poc freqüents, per aquest motiu estan classificades dins del grup de malalties anomenades rares. La cistinosi està causada per mutacions al gen CTNS, que codifica per una proteïna transmembrana del lisosoma que rep el nom de cistinosina. En canvi, la malaltia de NPC és deguda a mutacions al gen NPC1 o al gen NPC2, que codifiquen per una proteïna integral de la membrana lisosòmica i una proteïna soluble del lisosoma, respectivament, i aquestes reben el mateix nom que el gen, NPC1 i NPC2. El funcionament incorrecte d’aquestes proteïnes de transport dóna lloc a una acumulació de productes, diferent a ambdós casos, a l’interior del lisosoma, sent classificades com a malalties d’acumulació lisosòmica. Aquesta tesi doctoral s’ha centrat en l’anàlisi molecular de pacients afectes d’alguna d’aquestes dues malalties.
S’ha realitzat el primer estudi mutacional de cistinosi a la població espanyola, que ha permès la identificació de 15 mutacions diferents, 7 de les quals no havien estat descrites: tres mutacions de canvi de sentit (p.M1T, p.S270F i p.G309V), tres delecions (c.1-19_61del, c.295_310del i c.320_323delATCA) i una mutació de splicing (c.682-1G>T). La deleció de 57 kb és la mutació més freqüent a Espanya (38% dels al•lels) i conjuntament amb altres 5 mutacions representen el 73% dels al•lels estudiats. S’ha establert que els pacients amb fenotip clínic infantil tenen a ambdós al•lels mutacions que trunquen o que afecten aminoàcids conservats de les regions transmembrana de la proteïna. En canvi, la mutació p.S139F s’ha associat a la forma juvenil de la malaltia.
L’estudi mutacional realitzat a la malaltia de Niemann-Pick tipus C ha permès establir el genotip d’un gran nombre de pacients, identificant 74 mutacions diferents, 17 de les quals no havien estat descrites: set mutacions de canvi de sentit (p.P474A, p.G535V, p.F995L, p.F1079S, p.L1106P, p.G1209E i p.S1249G), dues mutacions sense sentit (p.Q775X i p.E1089X), dues insercions (p.L1117PfsX4 i p.I1061NfsX4), una deleció en pauta (p.N916del), quatre mutacions de splicing (c.58-3280C>G, c.882-28A>T, c.2604+5G>A i c.3591+5G>A) i la primera gran deleció que afecta al gen NPC1 i gens flanquejants. També s’han pogut establir correlacions genotip-fenotip per a un conjunt de mutacions.
També s’ha demostrat la implicació de diferents mecanismes cel•lulars en la malaltia de Niemann-Pick tipus C, segons els tipus de mutacions causants: el “splicing”, el procés de “nonsense-mediated mRNA decay” i la degradació proteica portada a terme pel proteasoma. S’han identificat mutacions intròniques profundes i s’ha caracteritzat el seu efecte en el mRNA, conjuntament amb el de les mutacions de “splicing” que afecten als llocs canònics. El mecanisme de NMD és el responsable de la degradació del mRNA en tots els al•lels analitzats que codifiquen per un PTC al gen NPC1. La majoria de mutacions de canvi de sentit analitzades condueixen a una reducció significativa o a l’absència de la proteïna NPC1, degut a què la proteïna NPC1 mutada és degradada per la via de la ubiquitina-proteasoma. La proteïna NPC1 mutada recuperada, després del tractament amb els inhibidors del proteasoma (ALLN i MG132), és capaç de disminuir els nivells de colesterol a totes les línies cel•lulars NPC estudiades. Aquesta observació podria obrir la porta a l’ús d’aquests fàrmacs com a futur tractament per a la malaltia de NPC causada per determinades mutacions de canvi de sentit.[eng] “Molecular aspects of both lysosomal transport diseases: cystinosis and Niemann-Pick disease type”. The cystinosis and Niemann-Pick disease type C (NPC) are two rare monogenic hereditary diseases. The cystinosis is caused by mutations in the gene CTNS, which encodes a transmembrane protein of the lysosome that is called cystinosin. NPC disease is caused by mutations in the NPC1 or NPC2 gene, encoding an integral lysosomal membrane protein and a soluble protein of the lysosome, respectively, and these are the same name as the gene, NPC1 and NPC2. The impaired transport leads to an accumulation of products, different in both cases, inside the lysosome, being classified as lysosomal storage disorders. This thesis has focused on the molecular analysis of patients with any of these diseases.
Molecular analysis in the Spanish cystinosis patients has allowed the identification of 15 different mutations, 7 of which had not been described. The 57-kb deletion is the most common mutation in Spain (38% of alleles) and together with other 5 mutations accounted for 73% of the studied alleles. The p.S139F mutation has been associated with the juvenile form of the disease.
Molecular analysis in NPC disease has established the mutation profile in a large number of patients. 74 different mutations have been identified, 17 of which had not been described previously, including the first large deletion affecting the whole NPC1 gene and flanking genes. Genotype-phenotype correlations have been established for several mutations.
Different cellular mechanisms are involving in NPC disease: splicing, nonsense-mediated mRNA decay and proteasomal degradation. Deep intronic mutations have been identified and the effect on the mRNA has been characterized. NMD process is responsible for the mRNA decay for all analyzed NPC1 PTC-encoding mutations. Several missense mutations lead to a significant reduction or absence of NPC1 protein, because the NPC1 mutant protein is degraded by the ubiquitin-proteasome pathway. Treatment with proteasome inhibitors partially reverses the NPC1 decrease and reduces cholesterol levels in all studied NPC cell lines. This observation might represent a therapeutical approach for future treatments of NPC disease caused by specific missense mutations
NEDD8 and Oxidative Stress
No full textAll living organisms are exposed to oxidative stress produced by reactive oxygen species (ROS)
(McCord, 2000; Pajares et al., 2015). ROS, which are highly unstable and reactive, play an important role in various cellular reactions and signals. The protein post-translation modifications (PTM) induced by ROS trigger progressive cell and tissue damage, eventually leading to pathophysiological defects (Devine et al., 2011; Sedelnikova et al., 2010). However, the presence of oxidized molecules does not necessarily imply stress, because many signaling
pathways are triggered by ROS (“redox signaling”) and act primarily to restore cellular homeostasis (Finkel, 2000). To maintain the cellular redox homeostasis, cells regulate the level of these free radicals through strictly controlled mechanisms, consisting of highly specific cellular antioxidant defense systems, including free radical neutralizing enzymes and antioxidant molecules (Antelmann and Helmann, 2011; Reichmann et al., 2018)
Magnetic Design Considerations to Improve Non-Linear Characteristics of Inductively Coupled Power Transfer Systems
No full textThe paper discusses the magnetic features of various pick-up arrangements of Inductively Coupled Power Transfer systems. The performance of the standard monorail system containing an E-pickup can be improved by using S- or Z-shaped magnetic circuits. Moreover, in the case of the Z-pickup, it is possible to benefit from the positive mutual coupling if an alternate-direction configuration is adopted
Development and Management of a Pick & Place Industrial Robot System
No full textreservedIl mondo dell’industria robotica è sempre più diffuso in molte realtà e, con loro, c’è sempre più necessità di software engineers e personale specializzato.
Ci sono vari ambienti e rami nel mondo della robotica e, in particolare, noi tratteremo di un problema in questa tesi: il Pick & Place.
Il Pick & Place coinsiste nel pensare e progettare a come dei robot possano spostare degli oggetti da un punto A ad un punto B, rispettando dei vincoli predeterminati come l’ordine della sequenza, posizione degli oggetti ecc..
Nella mia tesi presenterò il progetto sviluppato presso PFM, azienda che ha fornito gli strumenti per lo sviluppo:
Un sistema software di gestione di robot Rockwell che effettuano operazioni di Pick & Place
Il progetto è stato sviluppato e testato nel periodo di stage (7/8 mesi) in diverse fasi.
La tesi è divisa in 3 parti:
1. Dialogo con l’azienda per capire come approcciarsi al caso di studio (nastro + contronastro con più robot che spostano oggetti dal primo al secondo nastro)
2. Sviluppo di un simulatore su MatLab per analizzare le prestazioni di diverse logiche di presa
3. Passaggio della logica in ambiente PLC attraverso i linguaggi LD (Ladder Diagram) e ST (Structured Text) in ambiente Studio5000The world of robotics is becoming increasingly prevalent in many realities, and with them, there is an increasing need for software engineers and specialized personnel.
There are various environments and branches in the world of robotics and we will deal with one problem in this thesis: Pick & Place.
Pick & Place consists in thinking and designing how robots can move objects from point A to point B, respecting predetermined constraints such as the order of the sequence, position of the objects, etc...
In my thesis, I will present the project developed in PFM, the company that provided the tools for development:
A software system for managing Rockwell robots performing Pick & Place operations.
The thesis is divided into three parts:
1. Dialogue with the company to understand how to approach the case study (belt + counter-belt with several robots moving objects from the first to the second belt)
2. Development of a simulator on MatLab to analyse the performance of different pick logics
3. Transfer in PLC environment through LD (Ladder Diagram) and ST (Structured Text) languages in Studio5000 environmen
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Teaching seduction: Pick-Up Artist and masculinity
No full textreservedQuando si parla di maschilità tossiche, facendo quindi riferimento a comportamenti nocivi perpetuati da uomini, non si può non riferirsi al mondo dei Pick-Up Artist, ossia quel movimento di uomini che come scopo hanno quello di sedurre le donne. Nonostante esistano varie scuole di pensiero sull’argomento, questa realtà per la maggior parte dei casi si regge su teorie sessiste, misogine e pseudoscientifiche, che puntano a minare l’autostima delle donne per poi trarne vantaggio, continuando a promuovere una visione misogina del mondo. Esistono online, dove condividono il tutto su blog, forum e social network, ma non hanno mancato di espandersi anche su carta stampata. Risulterebbe quindi rilevante analizzare le caratteristiche generali dei libri che propongono per evidenziare schemi e tematiche che si ripetono nei loro ragionamenti e in dati come titolo, autori, case editrici, quarta di copertina, per comprendere quanto siano problematici e potenzialmente pericolosi i contenuti e gli insegnamenti che condividono
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