87 research outputs found
Exotic Brittle Star Interactions With Native Octocoral Epizoites: An Endemic Benthic Ctenophore in Peril?
Widespread and large populations of the exotic eastern Pacific ophiuroid brittle star Opthiothela mirabilis now occur in southeastern Florida, extending the range of this recently introduced species from southern Brazil northward to the eastern Caribbean Sea and Florida. The Florida brittle stars, representing two lineages, are epibionts on shallow (3-18 m depth), tropical/subtropical plexaurid (e.g., Eunicea spp., Muricea elongata) and gorgoniid (Antillogorgia spp.) octocorals. The scope of this study includes recent distributional records of O. mirabilis in south Florida, field abundances in relation to the cohabiting endemic ctenophore Coeloplana waltoni, behavioral observations of the ophiuroid, ctenophore and the predatory amphipod Caprella penantis, as well as a laboratory experiment testing the effects of the alien ophiuroid on the native ctenophore. Individuals of O. mirabilis have been collected near St. Lucie Inlet, extending its northern-most range by about 110 km since 2019. Two years of field sampling have demonstrated significant declines of the native, benthic ctenophore with increasing abundances of the exotic ophiuroid. Evidence suggests that the ophiuroid is negatively affecting the abundances of the ctenophore through interference competition, greatly aided by its abrasive armature of calcareous spines, plates and hooks. Sporadic and intense predation by a caprellid amphipod (Caprella penantis) also probably contributes to the ctenophore’s decline, but to a lesser extent than that caused by the ophiuroid. Adding to the risk of extinction of C. waltoni is its narrow requirement of living octocorals as hosts and restricted distribution in southeast Florida and the Bahamas
Chronic rejection of mouse kidney allografts
Chronic rejection of mouse kidney allografts.BackgroundChronic renal allograft rejection is the leading cause of late graft failure. However, its pathogenesis has not been defined.MethodsTo explore the pathogenesis of chronic rejection, we studied a mouse model of kidney transplantation and examined the effects of altering the expression of donor major histocompatibility complex (MHC) antigens on the development of chronic rejection.ResultsWe found that long-surviving mouse kidney allografts develop pathological abnormalities that resemble chronic rejection in humans. Furthermore, the absence of MHC class I or class II antigens did not prevent the loss of graft function nor alter the pathological characteristics of chronic rejection. Expression of transforming growth factor-β (TGF-β), a pleiotropic cytokine suggested to play a role in chronic rejection, was markedly enhanced in control allografts compared with isografts. However, TGF-β up-regulation was significantly blunted in MHC-deficient grafts. Nonetheless, these differences in TGF-β expression did not affect the character of chronic rejection, including intrarenal accumulation of collagens.ConclusionsReduced expression of either class I or II direct allorecognition pathways is insufficient to prevent the development of chronic rejection, despite a reduction in the levels of TGF-β expressed in the allograft. This suggests that the severity of chronic rejection is independent of the level of MHC disparity between donor and recipient and the level of TGF-β expression within the allograft
Grateful parents raising grateful children: Niche selection and the socialization of child gratitude
Given that children’s exposure to gratitude-related activities may be one way that parents can socialize gratitude in their children, we examined whether parents’ niche selection (i.e., tendency to choose perceived gratitude-inducing activities for their children) mediates the association between parents’ reports of their own and their children's gratitude. Parent-child dyads (N =101; children aged 6-9; 52% girls; 80% Caucasian; 85% mothers) participated in a laboratory visit and parents also completed a seven-day online diary regarding children’s gratitude. Decomposing specific indirect effects within a structural equation model, we found that parents high in gratitude were more likely to set goals to use niche selection as a gratitude socialization strategy, and thereby more likely to place their children in gratitude-related activities. Placement in these activities, in turn, was associated with more frequent expression of gratitude in children. We describe future directions for research on parents’ role in socializing gratitude in their children
Heralded generation of entangled photon pairs
Entangled photons are a crucial resource for quantum communication and linear
optical quantum computation. Unfortunately, the applicability of many
photon-based schemes is limited due to the stochastic character of the photon
sources. Therefore, a worldwide effort has focused in overcoming the limitation
of probabilistic emission by generating two-photon entangled states conditioned
on the detection of auxiliary photons. Here we present the first heralded
generation of photon states that are maximally entangled in polarization with
linear optics and standard photon detection from spontaneous parametric
down-conversion. We utilize the down-conversion state corresponding to the
generation of three photon pairs, where the coincident detection of four
auxiliary photons unambiguously heralds the successful preparation of the
entangled state. This controlled generation of entangled photon states is a
significant step towards the applicability of a linear optics quantum network,
in particular for entanglement swapping, quantum teleportation, quantum
cryptography and scalable approaches towards photonics-based quantum computing
Effect of soy protein isolate on the functional, pasting, and sensory acceptability of cassava starch-based custard
Open Access JournalFortification of custard powder (CP) with protein from cheap sources such as soybean could potentially improve its nutritive value but may alter its functional and sensory properties. This study was therefore conducted to determine the effect of soy protein isolate (SPI) inclusion (0%–20%) on some functional and sensory properties of cassava starch-based CP. Functional, pasting, and sensory acceptability were determined using standard methods. Increase in soy protein isolate significantly (p < .05) decreased dispersibility, packed bulk density, swelling power, peak, trough, breakdown, final, and setback viscosities, but increased least gelation concentration, water absorption capacity, and solubility index. This study further showed that despite increasing addition of SPI up to 20%, sensory acceptability of the cassava starch-based CP formulations did not differ significantly, and most of them had very similar acceptability when compared to that of corn starch-based CP
Quantum simulation of the wavefunction to probe frustrated Heisenberg spin systems
Quantum simulators are controllable quantum systems that can reproduce the
dynamics of the system of interest, which are unfeasible for classical
computers. Recent developments in quantum technology enable the precise control
of individual quantum particles as required for studying complex quantum
systems. Particularly, quantum simulators capable of simulating frustrated
Heisenberg spin systems provide platforms for understanding exotic matter such
as high-temperature superconductors. Here we report the analog quantum
simulation of the ground-state wavefunction to probe arbitrary Heisenberg-type
interactions among four spin-1/2 particles . Depending on the interaction
strength, frustration within the system emerges such that the ground state
evolves from a localized to a resonating valence-bond state. This spin-1/2
tetramer is created using the polarization states of four photons. The
single-particle addressability and tunable measurement-induced interactions
provide us insights into entanglement dynamics among individual particles. We
directly extract ground-state energies and pair-wise quantum correlations to
observe the monogamy of entanglement
High-speed linear optics quantum computing using active feed-forward
As information carriers in quantum computing, photonic qubits have the
advantage of undergoing negligible decoherence. However, the absence of any
significant photon-photon interaction is problematic for the realization of
non-trivial two-qubit gates. One solution is to introduce an effective
nonlinearity by measurements resulting in probabilistic gate operations. In
one-way quantum computation, the random quantum measurement error can be
overcome by applying a feed-forward technique, such that the future measurement
basis depends on earlier measurement results. This technique is crucial for
achieving deterministic quantum computation once a cluster state (the highly
entangled multiparticle state on which one-way quantum computation is based) is
prepared. Here we realize a concatenated scheme of measurement and active
feed-forward in a one-way quantum computing experiment. We demonstrate that,
for a perfect cluster state and no photon loss, our quantum computation scheme
would operate with good fidelity and that our feed-forward components function
with very high speed and low error for detected photons. With present
technology, the individual computational step (in our case the individual
feed-forward cycle) can be operated in less than 150 ns using electro-optical
modulators. This is an important result for the future development of one-way
quantum computers, whose large-scale implementation will depend on advances in
the production and detection of the required highly entangled cluster states.Comment: 19 pages, 4 figure
In Situ Rheological Method to Evaluate Feedstock Physical Properties Throughout Enzymatic Deconstruction
Feedstock physical properties determine not only downstream flow behavior, but also downstream process yields. Enzymatic treatment of pretreated feedstocks is greatly dependent on upstream feedstock physical properties and choice of pre-processing Technologies. Currently available enzyme assays have been developed to study biomass slurries at low concentrations of ≤ 1% w/w. At commercially relevant biomass concentrations of ≥15% w/w, pretreated feedstocks have sludge-like properties, where low free water restricts movement of unattached enzymes. This work is an account of the various steps taken to develop a method that helps identify the time needed for solid-like biomass slurries transition into liquid-like states during enzymatic hydrolysis. A pre-processing technology that enables feedstocks in achieving this transition sooner will greatly benefit enzyme kinetics and thereby overall process economics. Through this in situ rheological properties determining method, we compared a model feedstock, Avicel®PH101 cellulose, with acid pretreated corn stover. Novozymes Cellic®CTec2 (80 mg protein/g glucan) can reduce 25% (w/w) Avicel from solid-like to liquid-like state in 5.5 h, as the phase angles rise beyond 45° at this time. The same slurry needed 5.3 h to achieve liquid-like state with Megazyme endoglucanase (40 mg protein/g glucan). After 10.8 h, CTec2 slurry reached a phase angle of 89° or complete liquid-like state but Megazyme slurry peaked only to 64.7°, possibly due to inhibition by cello-oligomers. Acid pretreated corn stover at 30% (w/w) with a CTec2 protein loading of 80 mg/g glucan exhibited a solid-like to liquid-like transition at 37.8 h, which reflects the combined inhibition of low water activity and presence of lignin. The acid pretreated slurry also never achieved complete liquid-like state due to the presence of biomass residue. This method is applicable in several scenarios comparing varying combinations of pre-processing technologies, feedstock types, pretreatment chemistries, and enzymes. Using this method, we can generate a process chain with optimal flow behavior at commercially-relevant conditions
Processes controlling the distribution of aerosol particles in the lower marine boundary layer during the First Aerosol Characterization Experiment (ACE 1)
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