3,766 research outputs found

    Cash Settlement of Lean Hog Futures Contracts Reexamined

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    In 1997 the Chicago Mercantile Exchange replaced its live hog futures contract with a cash settlement mechanism based on a Lean Hog Index. Although cash settlement was expected to increase the use of the contract as a hedging tool, producers and packers are concerned that convergence between cash and futures prices is not occurring and that the volatility of the lean hog contract basis has increased in recent years. The purpose of the paper is to reexamine cash settlement of lean hog futures contracts as a hedging tool, focusing on basis behavior and management of basis risk. We also investigate alternative hedging instruments that take into account location differences between regional cash prices and the CME lean hog index. Our results indicate that basis has widened and its variability prior to expiration has increased in the cash settlement period. Nevertheless, there is no evidence that ex-ante basis risk has increased, suggesting that the ability to forecast basis prior to expiration has not decreased with cash settlement. Our findings indicate that a contract on a regional basis can reduce producer price risk and may increase market returns. The benefits of a regional basis appear to accrue from providing the producer with an opportunity to manage the variability in returns associated with both the price level and basis.basis behavior, cash settlement, ex-ante basis risk, lean hogs futures contract, regional basis, Agricultural Finance,

    Natural-based hydrogels for tissue engineering applications

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    In the field of tissue engineering and regenerative medicine, hydrogels are used as biomaterials to support cell attachment and promote tissue regeneration due to their unique biomimetic characteristics. The use of natural-origin materials significantly influenced the origin and progress of the field due to their ability to mimic the native tissuesâ extracellular matrix and biocompatibility. However, the majority of these natural materials failed to provide satisfactory cues to guide cell differentiation toward the formation of new tissues. In addition, the integration of technological advances, such as 3D printing, microfluidics and nanotechnology, in tissue engineering has obsoleted the first generation of natural-origin hydrogels. During the last decade, a new generation of hydrogels has emerged to meet the specific tissue necessities, to be used with state-of-the-art techniques and to capitalize the intrinsic characteristics of natural-based materials. In this review, we briefly examine important hydrogel crosslinking mechanisms. Then, the latest developments in engineering natural-based hydrogels are investigated and major applications in the field of tissue engineering and regenerative medicine are highlighted. Finally, the current limitations, future challenges and opportunities in this field are discussed to encourage realistic developments for the clinical translation of tissue engineering strategies.Authors acknowledge financial support from the European Union Framework Programme for Research and Innovation Horizon 2020 under European Research Council grant agreement No. 772817; FCT (Fundação para a Ciência e a Tecnologia) for individual fellowship CEECIND/01375/2017 (MGF); FCT for project PTDC/NAN-MAT/30595/2017; Xunta de Galicia for postdoctoral fellowship ED481B-2019-025 (AP); Norwegian Research Council (NFR) for project No. 287953

    Performance advantages of left-handed cricket batting talent

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    The purpose of this study was to examine performance advantages associated with batting stance, in the form of left- vs. right-handed dominant stance, and orthodox vs. reverse stance, of talented junior cricket batters within age-restricted competitions. Data were sourced from the national male younger age competition (YAC; Under-17;n= 237) and older age competition (OAC; Under-19;n= 302), as well as female YAC (Under-15;n= 234) and OAC (Under-18;n= 260) over a 4-year period. Left-hand dominant (LHD) batters were consistently overrepresented in the male YAC (Right: 69.2%; Left: 30.8%) and OAC (Right: 68.2%; Left: 31.8%) compared with the expected general population distribution. Male LHD batters exhibited a significantly (p< 0.05) higher batting aggregate (YAC: 116.82 +/- 84.75 vs. 137.84 +/- 89.74; OAC: 117.07 +/- 89.00 vs. 146.28 +/- 95.99), scored more runs (YAC: 19.65 +/- 12.32 vs. 23.96 +/- 14.71; OAC: 19.27 +/- 12.61 vs. 23.98 +/- 14.15), spent more time batting (YAC: 45.33 +/- 25.89 min vs. 54.59 +/- 28.62 min; OAC: 39.80 +/- 21.79 min vs. 49.33 +/- 27.41 min), and scored more boundary-4s per game (YAC: 1.83 +/- 1.40 vs. 2.44 +/- 1.87; OAC: 1.76 +/- 1.32 vs. 2.19 +/- 1.83), across both YAC and OAC groups with small effect sizes. No overrepresentation was present for either female group (YAC, Right: 88.5%/Left: 11.5%; OAC, Right: 90.0%/Left: 10.0%). Female LHD batters exhibited significantly higher batting aggregate (68.97 +/- 53.17 vs. 102.96 +/- 73.48), batting average (13.24 +/- 10.88 vs. 17.75 +/- 12.28), and spent more time batting per game (25.52 +/- 15.08 vs. 37.75 +/- 26.76 min), but only at the OAC level with small-moderate effects sizes. Finally, there were few performance advantages identified to batting with a reverse stance, with further work needed to clarify any potential biomechanical benefits. Team selection practices may exploit the left-handed advantage by over-selecting talented left-handed junior cricketers. Practical implications for coaches include creating practice environments that negate the negative frequency-dependent selection, such as providing more practice opportunities for their players against left-handed opponents

    Live lecture screencast recording: a proposal to simplify the tasks associated with content production for video-teaching

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    Se trata de un resumen (Abstract) de la contribución. El acuerdo de transferencia de copyright del trabajo completo es incompatible con el depósito del mismo en RIUMA.Se describe la implementación inicial de un método simplificado de grabación en directo de sesiones de clase en asignaturas de las Escuelas de Ingeniería de la Universidad de Málaga. La simplificación se logra al incorporar en la actividad diaria del aula ciertas características típicas de la grabación en diferido de mini videos docentes. En una configuración mínima se graba únicamente el audio y el video en pantalla de la clase, evitando los desafíos técnicos y las dificultades que implica la grabación de otros elementos como la pizarra. Esto implica el uso de anotaciones en pantalla en tiempo real para reemplazar completamente las anotaciones en la pizarra.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. I Plan Propio Integral de Docencia. Universidad de Málaga. Universidad de Málaga. Vicerectorado de Personal Docente e Investigador, Proyectos de Innovación Educativa (PIE 17-018

    Generating actionable predictions regarding MOOC learners' engagement in peer reviews

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    Peer review is one approach to facilitate formative feedback exchange in MOOCs; however, it is often undermined by low participation. To support effective implementation of peer reviews in MOOCs, this research work proposes several predictive models to accurately classify learners according to their expected engagement levels in an upcoming peer-review activity, which offers various pedagogical utilities (e.g. improving peer reviews and collaborative learning activities). Two approaches were used for training the models: in situ learning (in which an engagement indicator available at the time of the predictions is used as a proxy label to train a model within the same course) and transfer across courses (in which a model is trained using labels obtained from past course data). These techniques allowed producing predictions that are actionable by the instructor while the course still continues, which is not possible with post-hoc approaches requiring the use of true labels. According to the results, both transfer across courses and in situ learning approaches have produced predictions that were actionable yet as accurate as those obtained with cross validation, suggesting that they deserve further attention to create impact in MOOCs with real-world interventions. Potential pedagogical uses of the predictions were illustrated with several examples

    Reproducibility and clinical relevance of the ocular response analyzer in nonoperated eyes: corneal biomechanical and tonometric implications

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    To assess the reproducibility of the ocular response analyzer (ORA) in nonoperated eyes and the impact of corneal biomechanical properties on intraocular pressure (IOP) measurements in normal and glaucomatous eyes. METHODS: In the reliability study, two independent examiners obtained repeated ORA measurements in 30 eyes. In the clinical study, the examiners analyzed ORA and IOP-Goldmann values from 220 normal and 42 glaucomatous eyes. In both studies, Goldmann-correlated IOP measurement (IOP-ORAg), corneal-compensated IOP (IOP-ORAc), corneal hysteresis (CH), and corneal resistance factor (CRF) were evaluated. IOP differences of 3 mm Hg or greater between the IOP-ORAc and IOP-ORAg were considered outcome significant. RESULTS: Intraexaminer intraclass correlation coefficients and interexaminer concordance correlation coefficients ranged from 0.78 to 0.93 and from 0.81 to 0.93, respectively, for all parameters. CH reproducibility was highest, and the IOP-ORAg readings were lowest. The median IOP was 16 mm Hg with the Goldmann tonometer, 14.5 mm Hg with IOP-ORAg (P < 0.001), and 15.7 mm Hg with IOP-ORAc (P < 0.001). Outcome-significant results were found in 77 eyes (29.38%). The IOP-ORAc, CH, and CRF were correlated with age (r = 0.22, P = 0.001; r = -0.23, P = 0.001; r = -0.14, P = 0.02, respectively), but not the IOP-ORAg or IOP-Goldmann. CONCLUSIONS: The ORA provides reproducible corneal biomechanical and IOP measurements in nonoperated eyes. Considering the effect of ORA, corneal biomechanical metrics produces an outcome-significant IOP adjustment in at least one quarter of glaucomatous and normal eyes undergoing noncontact tonometry. Corneal viscoelasticity (CH) and resistance (CRF) appear to decrease minimally with increasing age in healthy adults

    Natural materials

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    The use of naturally occurring materials as scaffolds to support cell growth and proliferation significantly impacted the origin and progress of tissue engineering and regenerative medicine. However, the majority of these materials failed to provide adequate cues to guide cell differentiation toward the formation of new tissues. Over the past decade, a new generation of multifunctional and smart natural-based materials has been developed to provide biophysical and biochemical cues intended to specifically guide cell behavior. In this chapter, the use of extracellular matrix proteins and blood-derivatives intrinsic capacity to mimic the biophysical and biological characteristics of native tissues is reviewed. Furthermore, the design of a variety of nanostructures using the well-explored characteristics of nucleic acids is summarized. In the second section, the exploitation of supramolecular chemistry to create new dynamic functional hydrogels that mimic the extracellular matrix structure and/or composition is surveyed. Then, the incorporation of nanoelements in polymeric networks for the design of smart nanocomposite materials with tailored functionalities to guide cell behavior is introduced. Finally, the future perspectives in the development of new biomaterials for tissue engineering and regenerative medicine are presented.Te authors acknowledge the fnancial support of the European Union Framework Programme for Research and Innovation Horizon 2020, under the TEAMING grant agreement No 739572 – Te Discoveries CTR, Marie Skłodowska-Curie grant agreement No 706996 and European Research Council grant agreement No 726178; FCT (Fundação para a Ciência e a Tecnologia) and the Fundo Social Europeu através do Programa Operacional do Capital Humano (FSE/POCH) in the framework of Ph.D. grants PD/BD/113807/2015 (BBM) and PD/BD/129403/2017 (SMB), Post-Doc grant SFRH/ BPD/112459/2015 (RMD) and project SmarTendon (PTDC/NAN-MAT/30595/2017); Project NORTE01-0145-FEDER-000021 supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF

    Intrinsically bioactive cryogels based on platelet lysate nanocomposites for hemostasis applications.

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    The currently used hemostatic agents are highly effective in stopping hemorrhages but have a limited role in the modulation of the wound-healing environment. Herein, we propose an intrinsically bioactive hemostatic cryogel based on platelet lysate (PL) and aldehyde-functionalized cellulose nanocrystals (a-CNCs). PL has attracted great attention as an inexpensive milieu of therapeutically relevant proteins; however, its application as a hemostatic agent exhibits serious constraints (e.g., structural integrity and short shelf-life). The incorporation of a-CNCs reinforced the low-strength PL matrix by covalent cross-linking its amine groups that exhibit an elastic interconnected porous network after full cryogelation. Upon blood immersion, the PL-CNC cryogels absorbed higher volumes of blood at a faster rate than commercial hemostatic porcine gelatin sponges. Simultaneously, the cryogels released biomolecules that increased stem cell proliferation, metabolic activity, and migration as well as downregulated the expression of markers of the fibrinolytic process. In an in vivo liver defect model, PL-CNC cryogels showed similar hemostatic performance in comparison with gelatin sponges and normal material-induced tissue response upon subcutaneous implantation. Overall, owing to their structure and bioactive composition, the proposed PL-CNC cryogels provide an alternative off-the-shelf hemostatic and antibacterial biomaterial with the potential to deliver therapeutically relevant proteins in situ.The authors thank Hospital da Prelada (Porto, Portugal) for providing adipose tissue samples and Instituto Portugues do Sangue e Transplantacio-IPST (Portugal) (Porto, Portugal) for providing platelet concentrates. The authors would like to thank Alain Morais and Isabel Pires for their support in the in vivo procedure and histological evaluation, respectively. The authors would like to thank the anonymous reviewers for all useful and helpful comments on our manuscript. This work was supported by the European Research Council grant agreement no. 772817, FCT/MCTES (Fundacio para a Ciencia e a Tecnologia/Ministerio da Ciencia, Tecnologia, e Ensino Superior) and the Fundo Social Europeu atraves do Programa Operacional do Capital Humano (FSE/POCH) in the framework of Ph.D. grant PD/59/2013-PD/BD/113807/2015 (BBM) and CEECIND/01375/2017 (MGF), Norwegian Research Council for project no. 287953

    Cellulose nanocrystals of variable sulfation degrees can sequester specific platelet lysate-derived biomolecules to modulate stem cell response

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    The surface chemistry of cellulose nanocrystals was engineered to show variable sulfation degrees, which was exploited to modulate platelet lysate-derived biomolecule sequestration and presentation. The protein coronas developed on CNC surfaces were characterized and it was demonstrated how they promote different signaling effects on human adipose-derived stem cell behavior.The research has received funding from PTDC/NAN-MAT/30595/2017, ERC Grant No. 772817; FCT/MCTES for PD/59/2013 - PD/BD/113807/2015, for ITI Research grant 1306_2018,ROTEIRO/0028/2013, and LISBOA-01-0145-FEDER-022125
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