Conceptual centrality and property induction

This thesis examines property generalization among concepts. Its primary objective is to investigate the hypothesis that the more central a feature for a concept, the higher its generalizability to other concepts that share a similar structure (features and dependencies). Its secondary objectives are to examine the relative contributions of feature centrality and feature variability in property induction, whether centrality offers a domain-general or a domain-specific constraint, and whether centrality can operate under conditions of vagueness. Experiments 1 and 2 addressed the centrality hypothesis with centrality measured, whereas Experiments 3 to 14 and 17 with centrality manipulated. Relative feature centrality was manipulated as follows: from a single-dependency chain (Experiments 3 to 7), from the number of properties that depended upon a feature (Experiments 8 to 11 and 17), and from the centrality of the properties that depended upon the critical features (Experiments 12 to 14). The results support the centrality hypothesis. Experiments 12 to 16 addressed the relative contributions of centrality and variability in property induction. Experiments 12 to 14 pitted a central and variable property against a less central and less variable property in judgments of frequency and inductive strength. The results suggest that property induction depends on centrality rather than frequency information, and that centrality can bias the perception of frequency (although the latter results were not clear-cut). Experiments 15 and 16 pitted centrality against variability in information seeking. The results show that centrality information is sought more often than variability information to make an inference, especially amongst dissimilar concepts. Experiments 1 to 16 used animal categories. Experiment 17 examined the centrality hypothesis with artifact categories. The results show centrality effects. Taken together, the Experiments suggest that centrality offers a domain-general constraint. Experiments 5, 8 to 11, and 17 left the properties that depended upon a candidate feature unspecified. A centrality effect was still obtained. The results suggest that centrality can operate under conditions of vagueness. The results are discussed in terms of theories of conceptual structure and models of category-based inference. A model to capture the present findings is also sketched

Novel Atmospheric Monitoring for the H.E.S.S. site and its Industrial Applications

This thesis concerns the atmospheric monitoring instrumentation for the H.E.S.S. (High Energy Stereoscopic System) gamma-ray telescope site and the adaptation of such instruments for commercial use. The effect of the atmosphere on the H.E.S.S. telescopes' response has been demonstrated and the technicalities associated with the atmospheric monitoring instruments have been studied in depth. The responses of a LIDAR (Light Detection And Ranging) and a transmissometer have been checked by customised MODTRAN (MODerate resolution atmospheric TRANsmission) routines. This process revealed a malfunction of the LIDAR, whose raw data was independently treated to yield meaningful results. More importantly, the `Durham-designed' transmissometer, manufactured to operate during the night in parallel with the H.E.S.S. telescopes, was successfully adapted for day-light operation. As a result Durham prototype gained strong interest from Aeronautical & General Instruments Limited (AGI) in Dorset, who are particularly interested in the airport applications, and see the Durham instrument as a potential replacement for the transmissometer which they manufacture currently and is coming to the end of its useful design life. Durham University and AGI drew up a license agreement to pursue further development of the instrument. The resulting Durham aviation transmissometer meets the accuracy requirements for the Runway Visual Range (RVR) assessment imposed by both the World Meteorological Organisation (WMO) and the International Civil Aviation Organisation (ICAO). Moreover, the Durham instrument is easy to align, uses very little power, and is lightweight and portable, enabling its use not only in civil airports, at altitudes exceeding all prior-art aviation transmissometers, but also in tactical military applications, such as remote landing strips

Unpacking estimates of task duration: The role of typicality and temporality

Research in task duration judgment has shown that unpacking a multifaceted task into components prior to estimating its duration increases estimates. In three studies, we find that unpacking a complex task can increase, decrease, or leave unaffected task duration estimates depending on the typicality of the unpacked components and their temporal position in the task sequence. Unpacking atypical long components increases task duration estimates, while unpacking atypical short components decreases estimates (Study 1). Unpacking atypical early components increases task duration estimates, while unpacking atypical late components decreases estimates (Study 2). Unpacking typical early or late components leaves estimates unaffected (Study 3). We explain these results based on the idea that task duration estimation involves a mental simulation process, and by drawing on theories of unpacking in probability judgment that emphasize the role of the typicality of the unpacked components. These findings hint at a deep conceptual link between probability judgment and task duration estimation but also show differences, such as the influence that temporality exerts on estimated duration. © 2013 Elsevier Inc

Monte Carlo simulations of infinitely dilute solutions of amphiphilic diblock star copolymers

Single-chain Monte Carlo simulations of amphiphilic diblock star copolymers were carried out in continuous space using implicit solvents. Two distinct architectures were studied: stars with the hydrophobic blocks attached to the core, and stars with the polar blocks attached to the core, with all arms being of equal length. The ratio of the lengths of the hydrophobic block to the length of the polar block was varied from 0 to 1. Stars with 3, 6, 9 or 12 arms, each of length 10, 15, 25, 50, 75 and 100 Kuhn segments were analysed. Four distinct types of conformations were observed for these systems. These, apart from studying the snapshots from the simulations, have been quantitatively characterised in terms of the mean-squared radii of gyration, mean-squared distances of monomers from the centre-of-mass, asphericity indices, static scattering form factors in the Kratky representation as well as the intra-chain monomer-monomer radial distribution functions.Comment: 12 pages, 11 ps figures. Accepted for publication in J. Chem. Phy

Sequential crystallization and morphology of triple crystalline biodegradable PEO-b-PCL-b-PLLA triblock terpolymers

et al.The sequential crystallization of poly(ethylene oxide)-b-poly(ε-caprolactone)-b-poly(l-lactide) (PEO-b-PCL-b-PLLA) triblock terpolymers, in which the three blocks are able to crystallize separately and sequentially from the melt, is presented. Two terpolymers with identical PEO and PCL block lengths and two different PLLA block lengths were prepared, thus the effect of increasing PLLA content on the crystallization behavior and morphology was evaluated. Wide angle X-ray scattering (WAXS) experiments performed on cooling from the melt confirmed the triple crystalline nature of these terpolymers and revealed that they crystallize in sequence: the PLLA block crystallizes first, then the PCL block, and finally the PEO block. Differential scanning calorimetry (DSC) analysis further demonstrated that the three blocks can crystallize from the melt when a low cooling rate is employed. The crystallization process takes place from a homogenous melt as indicated by small angle X-ray scattering (SAXS) experiments. The crystallization and melting enthalpies and temperatures of both PEO and PCL blocks decrease as PLLA content in the terpolymer increases. Polarized light optical microscopy (PLOM) demonstrated that the PLLA block templates the morphology of the terpolymer, as it forms spherulites upon cooling from the melt. The subsequent crystallization of PCL and PEO blocks occurs inside the interlamellar regions of the previously formed PLLA block spherulites. In this way, unique triple crystalline mixed spherulitic superstructures have been observed for the first time. As the PLLA content in the terpolymer is reduced the superstructural morphology changes from spherulites to a more axialitic-like structure.We gratefully acknowledge funds received through the following projects: “MAT2014-53437-C2-P, MAT2012-31088 (Spanish-MINECO and EU)”, UPV/EHU (UFI 11/56) and GIC IT-586-13, IT-654-13 (Basque Government).Peer Reviewe

Well-defined homopolypeptides, copolypeptides, and hybrids of Poly(l-proline)

l-Proline is the only, out of 20 essential, amino acid that contains a cyclized substituted α-amino group (is formally an imino acid), which restricts its conformational shape. The synthesis of well-defined homo- and copolymers of l-proline has been plagued either by the low purity of the monomer or the inability of most initiating species to polymerize the corresponding N-carboxy anhydride (NCA) because they require a hydrogen on the 3-N position of the five-member ring of the NCA, which is missing. Herein, highly pure l-proline NCA was synthesized by using the Boc-protected, rather than the free amino acid. The protection of the amine group as well as the efficient purification method utilized resulted in the synthesis of highly pure l-proline NCA. The high purity of the monomer and the use of an amino initiator, which does not require the presence of the 3-N hydrogen, led for the first time to well-defined poly(l-proline) (PLP) homopolymers, poly(ethylene oxide)-b-poly(l-proline), and poly(l-proline)-b-poly(ethylene oxide)-b-poly(l-proline) hybrids, along with poly(γ-benzyl-l-glutamate)-b-poly(l-proline) and poly(Boc-l-lysine)-b-poly(l-proline) copolypeptides. The combined characterization (NMR, FTIR, and MS) that results for the l-proline NCA revealed its high purity. In addition, all synthesized polymers exhibit high molecular and compositional homogeneity

Direct Identification of Three Crystalline Phases in PEO-b-PCL-b-PLLA Triblock Terpolymer by In Situ Hot-Stage Atomic Force Microscopy

Unformatted preprint version of the submitted articleIn this work, we provide a detailed description of the tri-lamellar nanoscale morphology of a triple crystalline PEO-b-PCL-b-PLLA triblock terpolymer obtained by Hot-Stage Atomic Force microscopy (AFM) imaging and Wide Angle X-ray scattering (WAXS) analysis for the first time. The precursor PCL-b-PLLA diblock copolymer has also been included in the study for comparison purposes. A two-step crystallization protocol has been applied to create a distinct lamellar morphology. Both WAXS and AFM revealed the double crystalline nature of the diblock copolymer. However, the identification of multiple crystalline phases in the triblock terpolymer by AFM and WAXS at room temperature is not straightforward. The advantages of hot-stage AFM allowed following the evolution of the lamellar morphology and the successive melting of the tricrystalline PEO-b-PCL-b-PLLA sample during heating. Taking into account the melting temperature of each crystalline block, the existing lamellar populations were clearly identified. At 45 °C, the thinnest lamellae disappeared, due to the melting of PEO crystals. The medium size lamellae disappeared at 60 °C when PCL crystals melt. At that temperature, the only remaining crystals are those of the PLLA block. AFM mechanical modulus images provide further evidence of the lamellar self-assembly of the triblock terpolymer. The nanoscale arrangement includes lamellae of PCL, PEO, or both in between the PLLA lamellae. Hot-Stage AFM is a valuable technique to elucidate the morphological features of complex multi-crystalline systems.This work has received funding from the European Union´s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 778092, from MINECO, project: MAT2017-83014-C2-1-P and from the Basque Government through grant IT1309-19. We are grateful to the National Science Foundation of China (nos. 51773182, 51973202), The Young Out-standing Teachers of the University in Henan Province (2019GGJS003). N.H. acknowledges the support of King Abdullah University of Science and Technology (KAUST)

Generating Triple Crystalline Superstructures in Melt Miscible PEO-b-PCL-b-PLLA Triblock Terpolymers by Controlling Thermal History and Sequential Crystallization

The morphology, crystallization behavior and properties of multi-crystalline polymer systems based on triple crystalline biodegradable PEO-b-PCL-b-PLLA triblock terpolymers are reviewed. The triblock terpolymers, with increasing PLLA content, exhibited a triple crystalline nature. Upon cooling from melt, the PLLA block crystallizes first and templates the spherulitic morphology of the terpolymer. Then, the PCL block crystalizes and, lastly, the PEO block. These triblock terpolymers are probably melt miscible, as SAXS experiments confirmed. Thus, the crystallization of PCL and PEO blocks takes place within the interlamellar zones of the PLLA spherulites that were formed previously. Therefore, the lamellae of PLLA, PCL and PEO exist side-by-side within a unique spherulite, constituting a novel triple crystalline superstructure. The theoretical analysis of SAXS curves implies that only one lamella of either PCL or PEO can occupy the interlamellar space in between two contiguous lamellae of PLLA. Several complex competitive effects such as plasticizing, nucleation, anti-plasticizing and confinement take place during the isothermal crystallization of each block in the terpolymers. New results on how Successive Self-nucleation and Annealing (SSA) thermal treatment can be used as an additional suitable technique to properly separate the three crystalline phases in these triple crystalline triblock terpolymers are also included in this contribution.The POLYMAT/UPV/EHU team would like to acknowledge funding from MINECO through project: MAT2017-83014-C2-1-P, and from ALBA synchrotron facility. We also acknowledge funding by the European Union´s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 778092. The support of the National Key R&D Program of China (2017YFE0117800) is also gratefully acknowledged

Poly(Sarcosine)-Based Nano-Objects with Multi-Protease Resistance by Aqueous Photoinitiated Polymerization-Induced Self-Assembly (Photo-PISA)

Poly­(sarcosine) (PSar) is a non-ionic hydrophilic polypeptoid with numerous biologically relevant properties, making it an appealing candidate for the development of amphiphilic block copolymer nanostructures. In this work, the fabrication of poly­(sarcosine)-based diblock copolymer nano-objects with various morphologies via aqueous reversible addition–fragmentation chain-transfer (RAFT)-mediated photoinitiated polymerization-induced self-assembly (photo-PISA) is reported. Poly­(sarcosine) was first synthesized via ring-opening polymerization (ROP) of sarcosine N-carboxyanhydride, using high-vacuum techniques. A small molecule chain transfer agent (CTA) was then coupled to the active ω-amino chain end of the telechelic polymer for the synthesis of a poly­(sarcosine)-based macro-CTA. Controlled chain-extensions of a commercially available water-miscible methacrylate monomer (2-hydroxypropyl methacrylate) were achieved via photo-PISA under mild reaction conditions, using PSar macro-CTA. Upon varying the degree of polymerization and concentration of the core-forming monomer, morphologies evolving from spherical micelles to worm-like micelles and vesicles were accessed, as determined by dynamic light scattering and transmission electron microscopy, resulting in the construction of a detailed phase diagram. The resistance of both colloidally stable empty vesicles and enzyme-loaded nanoreactors against degradation by a series of proteases was finally assessed. Overall, our findings underline the potential of poly­(sarcosine) as an alternative corona-forming polymer to poly­(ethylene glycol)-based analogues of PISA assemblies for use in various pharmaceutical and biomedical applications