28 research outputs found
Voice Shoppers: From Information Gaps to Choice Gaps in Consumer Markets
Recent years have seen exponential growth in the use of voice shoppers â artificial intelligenceâbased algorithms installed on digital voice assistants, such as Alexa and Google Assistant, that buy products based on verbal requests received from consumers. This game-changing switch to semi-automated shopping is shaking up markets by reshaping consumerâsupplier relationships, as well as the business models of suppliers and search services. Voice shoppers benefit consumers by offering speedier and more sophisticated transactions while reducing search and transaction costs. At the same time, consumersâ voluntary delegation of their search powers and product selection creates what we call a âchoice gap,â wherein the voice shopper chooses the product to be offered to the consumer. This gap is distinct from the commonly recognized information gap, which exists when suppliers possess more information than consumers. The choice gap might create a misalignment between consumer preferences and the products actually sold, which harms consumers as well as the function of markets. Yet market forces cannot be relied upon to remedy this market failure. Despite the significant consequences of this market failure, the negative effects of the choice gap are currently undertreated. Consumer protection and antitrust laws are ill-suited to the task. To remedy this, we suggest that transactions conducted by voice shoppers be reviewed under agency law. Agency law enables the application of fiduciary, performance, and information duties that protect consumersâ interests in the transaction, rather than consumer choice. Such duties can reduce the choice gap, improve consumer welfare, and restore market performance. Our findings and suggestions have relevance well beyond voice shoppers, for technologies which completely automate consumer choice without any human involvement, which are the future of commerce
Ramsey-nice families of graphs
For a finite family of fixed graphs let be
the smallest integer for which every -coloring of the edges of the
complete graph yields a monochromatic copy of some . We
say that is -nice if for every graph with
and for every -coloring of there exists a
monochromatic copy of some . It is easy to see that if
contains no forest, then it is not -nice for any . It seems
plausible to conjecture that a (weak) converse holds, namely, for any finite
family of graphs that contains at least one forest, and for all
(or at least for infinitely many values of ),
is -nice. We prove several (modest) results in support of this
conjecture, showing, in particular, that it holds for each of the three
families consisting of two connected graphs with 3 edges each and observing
that it holds for any family containing a forest with at most 2
edges. We also study some related problems and disprove a conjecture by
Aharoni, Charbit and Howard regarding the size of matchings in regular
3-partite 3-uniform hypergraphs.Comment: 20 pages, 2 figure
Membrane interaction of pegylated superparamagnetic nanoparticles
Iron oxide core-shell nanoparticles are gaining ever increasing interest for separation and imaging in biotechnology and biomedicine1,2, due to supposed low cytotoxicity and their superparamagnetic properties. Hydrophilic polymer-coated nanoparticles are believed to have low nonspecific interactions in biological systems, but much additional work in-vitro and in-vivo is needed to understand their detailed interactions with proteins, membranes and cells. We investigated monodisperse (SD\u3c5%), single-crystalline and superparamagnetic magnetite nanoparticles of different core size and densely grafted with poly(ethylene glycol) (Mw=5kDa), with particular emphasis on their interaction with biological membranes. Membrane interactions will determine nonspecific recognition and uptake by cells. These nanoparticles demonstrated no cytotoxicity and low cell uptake in in-vitro culture of HeLa and HEK cell lines.
However, using Quartz Crystal Microbalance (QCM) a strong DLVO-type interaction could be demonstrated with anionic membranes that simulate eukaryote membranes. This interaction was only present in nonphysiological buffer with low ionic strength. Only low, weak and transient binding was observed to zwiterionic phosphocholine membranes. Core size seems to have an effect, with the smallest core size (3.3nm) yielding the strongest interactions while 8nm cores displayed almost no interaction. These results imply that dense polymer grafting and nanoparticle curvature are crucial parameters to control interactions between biomedical core-shell nanoparticles and their biomolecular environment, in particular cell membranes. The interaction between nanoparticle and membrane was furthermore shown to not perturb membrane structure by Differential Scanning Calorimetry (DSC).
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Modulation of spontaneous locomotor and respiratory drives to hindlimb motoneurons temporally related to sympathetic drives as revealed by Mayer waves
In this study we investigated how the networks mediating respiratory and locomotor drives to lumbar motoneurons interact and how this interaction is modulated in relation to periodic variations in blood pressure (Mayer waves). Seven decerebrate cats, under neuromuscular blockade, were used to study central respiratory drive potentials (CRDPs, usually enhanced by added CO(2)) and spontaneously occurring locomotor drive potentials (LDPs) in hindlimb motoneurons, together with hindlimb and phrenic nerve discharges. In four of the cats both drives and their voltage-dependent amplification were absent or modest, but in the other three, one or other of these drives was common and the voltage-dependent amplification was frequently strong. Moreover, in these three cats the blood pressure showed marked periodic variation (Mayer waves), with a slow rate (periods 9â104 s, mean 39 ± 17 SD). Profound modulation, synchronized with the Mayer waves was seen in the occurrence and/or in the amplification of the CRDPs or LDPs. In one animal, where CRDPs were present in most cells and the amplification was strong, the CRDP consistently triggered sustained plateaux at one phase of the Mayer wave cycle. In the other two animals, LDPs were common, and the occurrence of the locomotor drive was gated by the Mayer wave cycle, sometimes in alternation with the respiratory drive. Other interactions between the two drives involved respiration providing leading events, including co-activation of flexors and extensors during post-inspiration or a locomotor drive gated or sometimes entrained by respiration. We conclude that the respiratory drive in hindlimb motoneurons is transmitted via elements of the locomotor central pattern generator. The rapid modulation related to Mayer waves suggests the existence of a more direct and specific descending modulatory control than has previously been demonstrated
Strangeness nuclear physics: a critical review on selected topics
Selected topics in strangeness nuclear physics are critically reviewed. This
includes production, structure and weak decay of --Hypernuclei, the
nuclear interaction and the possible existence of bound
states in nuclei. Perspectives for future studies on these issues are also
outlined.Comment: 63 pages, 51 figures, accepted for publication on European Physical
Journal
Voice Shoppers: From Information Gaps to Choice Gaps in Consumer Markets
Recent years have seen exponential growth in the use of voice shoppers â artificial intelligenceâbased algorithms installed on digital voice assistants, such as Alexa and Google Assistant, that buy products based on verbal requests received from consumers. This game-changing switch to semi-automated shopping is shaking up markets by reshaping consumerâsupplier relationships, as well as the business models of suppliers and search services. Voice shoppers benefit consumers by offering speedier and more sophisticated transactions while reducing search and transaction costs. At the same time, consumersâ voluntary delegation of their search powers and product selection creates what we call a âchoice gap,â wherein the voice shopper chooses the product to be offered to the consumer. This gap is distinct from the commonly recognized information gap, which exists when suppliers possess more information than consumers. The choice gap might create a misalignment between consumer preferences and the products actually sold, which harms consumers as well as the function of markets. Yet market forces cannot be relied upon to remedy this market failure. Despite the significant consequences of this market failure, the negative effects of the choice gap are currently undertreated. Consumer protection and antitrust laws are ill-suited to the task. To remedy this, we suggest that transactions conducted by voice shoppers be reviewed under agency law. Agency law enables the application of fiduciary, performance, and information duties that protect consumersâ interests in the transaction, rather than consumer choice. Such duties can reduce the choice gap, improve consumer welfare, and restore market performance. Our findings and suggestions have relevance well beyond voice shoppers, for technologies which completely automate consumer choice without any human involvement, which are the future of commerce
Fluorescent Magnetopolymersomes: A Theranostic Platform to Track Intracellular Delivery
We present a potential theranostic delivery platform based on the amphiphilic diblock copolymer polybutadiene-block-poly (ethylene oxide) combining covalent fluorescent labeling and membrane incorporation of superparamagnetic iron oxide nanoparticles for multimodal imaging. A simple self-assembly and labeling approach to create the fluorescent and magnetic vesicles is described. Cell uptake of the densely PEGylated polymer vesicles could be altered by surface modifications that vary surface charge and accessibility of the membrane active species. Cell uptake and cytotoxicity were evaluated by confocal microscopy, transmission electron microscopy, iron content and metabolic assays, utilizing multimodal tracking of membrane fluorophores and nanoparticles. Cationic functionalization of vesicles promoted endocytotic uptake. In particular, incorporation of cationic lipids in the polymersome membrane yielded tremendously increased uptake of polymersomes and magnetopolymersomes without increase in cytotoxicity. Ultrastructure investigations showed that cationic magnetopolymersomes disintegrated upon hydrolysis, including the dissolution of incorporated iron oxide nanoparticles. The presented platform could find future use in theranostic multimodal imaging in vivo and magnetically triggered delivery by incorporation of thermorepsonsive amphiphiles that can break the membrane integrity upon magnetic heating via the embedded superparamagnetic nanoparticles
Stealth Nanoparticles Grafted with Dense Polymer Brushes Display Adsorption of Serum Protein Investigated by Isothermal Titration Calorimetry
Coreâshell
nanoparticles receive much attention for their
current and potential applications in life sciences. Commonly, a dense
shell of hydrated polymer, a polymer brush, is grafted to improve
colloidal stability of functional nanoparticles and to prevent protein
adsorption, aggregation, cell recognition, and uptake. Until recently,
it was widely assumed that a polymer brush shell indeed prevents strong
association of proteins and that this leads to their superior âstealthâ
properties in vitro and in vivo. We show using <i>T</i>-dependent
isothermal titration calorimetry on well-characterized monodisperse
superparamagnetic iron oxide nanoparticles with controlled dense stealth
polymer brush shells that âstealthâ coreâshell
nanoparticles display significant attractive exothermic and enthalpic
interactions with serum proteins, despite having excellent colloidal
stability and negligible nonspecific cell uptake. This observation
is at room temperature shown to depend only weakly on variation of
iron oxide core diameter and type of grafted stealth polymer: polyÂ(ethylene
glycol), polyÂ(ethyl oxazoline), polyÂ(isopropyl oxazoline), and polyÂ(<i>N</i>-isopropyl acrylamide). Polymer brush shells with a critical
solution temperature close to body temperature showed a strong temperature
dependence in their interactions with proteins with a significant
increase in protein binding energy with increased temperature. The
stoichiometry of interaction is estimated to be near 1:1 for PEGylated
nanoparticles and up to 10:1 for larger thermoresponsive nanoparticles,
whereas the average free energy of interaction is enthalpically driven
and comparable to a weak hydrogen bond
Locomotion of micromotors due to liposome disintegration
Synthetic micromotors are evaluated extensively in a range of biomedical, microscale transport, and environmental applications. Fundamental insight into micromotors that exhibit locomotion due to triggered disintegration of their associated liposomes is provided. Directed self-propulsion is observed when the lipid vesicles are solubilized using Triton X-100 (TX) and bile at sufficiently high concentrations. Directional motion, initiated by a propagating TX or bile gradient, is found when using a sufficiently high concentration of solubilization agents. On the other hand, a low bile concentration results in short-term reverse directional motion. The experimental and theoretical considerations offer valid fundamental understanding to complement the list of explored locomotion mechanisms for micromotors
Simulated Pain and Cervical Motion in Patients with Chronic Disorders of the Cervical Spine
The primary objective of the present study was to determine how simulated severe cervical pain affects cervical motion in patients suffering from two distinct chronic cervical disorders: whiplash (n=25) and degenerative changes (n=25). The second objective was to derive an index that would allow the differentiation of maximal from submaximal performances of cervical range of motion. Patients first performed maximal movement of the head (maximal effort) in each of the six primary directions and then repeated the test as if they were suffering from a much more intense level of pain (submaximal effort). All measurements were repeated within four to seven days. In both groups, there was significant compression of cervical motion during the submaximal effort. This compression was also highly stable on a test-retest basis. In both groups, a significantly higher average coefficient of variation was associated with the imagined pain and it was significantly different between the two clinical groups. In the whiplash group, a logistic regression model allowed the derivation of coefficient of variation-based cutoff scores that might, at selected levels of probability and an individual level, identify chronic whiplash patients who intentionally magnify their motion restriction using pain as a cue. However, the relatively small and very stable compression of cervical motion under pain simulation supports the view that the likelihood that chronic whiplash patients are magnifying their restriction of cervical range of motion using pain as a cue is very low