4,066 research outputs found
Phonon arithmetic in a trapped ion system
Single-quantum level operations are important tools to manipulate a quantum state. Annihilation or creation of single particles translates a quantum state to another by adding or subtracting a particle, depending on how many are already in the given state. The operations are probabilistic and the success rate has yet been low in their experimental realization. Here we experimentally demonstrate (near) deterministic addition and subtraction of a bosonic particle, in particular a phonon of ionic motion in a harmonic potential. We realize the operations by coupling phonons to an auxiliary two-level system and applying transitionless adiabatic passage. We show handy repetition of the operations on various initial states and demonstrate by the reconstruction of the density matrices that the operations preserve coherences. We observe the transformation of a classical state to a highly non-classical one and a Gaussian state to a non-Gaussian one by applying a sequence of operations deterministically
Effect of betaine and ascorbic acid in drinking water on growth performance and blood biomarkers in meat ducks exposed to heat stress
The aim of this study was to compare the effect of drinking water that contains various levels of ascorbic acid (AA) and betaine (BT) on growth performance and blood biomarkers in meat ducks exposed to heat stress. Six hundred and forty one-day-old Cherry Valley ducks were randomly assigned to one of seven treatment groups: i) control group, drinking water without ascorbic acid or betaine, ii) AA100, drinking water containing ascorbic acid at 100 milligrams per litre, iii) AA200, drinking water containing ascorbic acid at 200 milligrams per litre, iv) AA300, drinking water containing ascorbic acid at 300 milligrams per litre, v) BT400, drinking water containing betaine at 400 milligrams per litre, vi) BT800, drinking water containing betaine at 800 milligrams per litre, and vii) BT1200, drinking water containing betaine at 1200 milligrams per litre. The ducks were exposed to heat stress (11:00 to 17:00, 33 °C to 43 °C, relative humidity 70%, artificially controlled-environment houses) from the 22nd to 42nd days. Ducks from treatment groups AA300 and BT1200 displayed significantly increased bodyweight gains compared with those in the control group. Blood levels of glucose, and activities of aspartate aminotransferase and alanine aminotransferase in all treatment groups were significantly lower than those observed in the control group. Red blood cell count, platelet number, electrolytes and blood gas concentrations were significantly higher in all treatment groups compared with those in the control group. Blood pH levels in all treatment groups were lower than those in the control group. In conclusion, drinking water containing ascorbic acid or betaine improved the growth performance via biomarker homeostasis in blood of meat ducks exposed to heat stress.Keywords: body weight gain, blood lipid, red blood cell, electrolytes; blood gas, blood p
Proteolytic degradation and potential role of onconeural protein cdr2 in neurodegeneration
Cerebellar degeneration-related protein 2 (cdr2) is expressed in the central nervous system, and its ectopic expression in tumor cells of patients with gynecological malignancies elicits immune responses by cdr2-specific autoantibodies and T lymphocytes, leading to neurological symptoms. However, little is known about the regulation and function of cdr2 in neurodegenerative diseases. Because we found that cdr2 is highly expressed in the midbrain, we investigated the role of cdr2 in experimental models of Parkinson's disease (PD). We found that cdr2 levels were significantly reduced after stereotaxic injection of 1-methyl-4-phenylpyridinium (MPP+) into the striatum. cdr2 levels were also decreased in the brains of post-mortem PD patients. Using primary cultures of mesencephalic neurons and MN9D cells, we confirmed that MPP + reduces cdr2 in tyrosine hydroxylase-positive dopaminergic neuronal cells. The MPP+-induced decrease of cdr2 was primarily caused by calpain-and ubiquitin proteasome system-mediated degradation, and cotreatment with pharmacological inhibitors of these enzymes or overexpression of calcium-binding protein rendered cells less vulnerable to MPP+-mediated cytotoxicity. Consequently, overexpression of cdr2 rescued cells from MPP+-induced cytotoxicity, whereas knockdown of cdr2 accelerated toxicity. Collectively, our findings provide insights into the novel regulatory mechanism and potentially protective role of onconeural protein during dopaminergic neurodegeneration. © 2016 Macmillan Publishers Limited All rights reserved.1
Constraints on the geometry of the subducted Gorda Plate from converted phases generated by local earthquakes
Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 126(2), (2021): e2020JB019962, https://doi.org/10.1029/2020JB019962.The largest slip in great megathrust earthquakes often occurs in the 10–30 km depth range, yet seismic imaging of the material properties in this region has proven difficult. We utilize a dense onshore‐offshore passive seismic dataset from the southernmost Cascadia subduction zone where seismicity in the mantle of the subducted Gorda Plate produces S‐to‐P and P‐to‐S conversions generated within a few km of the plate interface. These conversions typically occur in the 10–20 km depth range at either the top or bottom of a ∼5 km thick layer with a high Vp/Vs that we infer to be primarily the subducted crust. We use their arrival times and amplitudes to infer the location of the top and bottom of the subducted crust as well as the velocity contrasts across these discontinuities. Comparing with both the Slab1.0 and the updated Slab2 interface models, the Slab2 model is generally consistent with the converted phases, while the Slab1.0 model is 1–2 km deeper in the 2–20 km depth range and ∼6–8 km too deep in the 10–20 km depth range between 40.25°N and 40.4°N. Comparing the amplitudes of the converted phases to synthetics for simplified velocity structures, the amplitude of the converted phases requires models containing a ∼5 km thick zone with at least a ∼10%–20% reduction in S wave velocity. Thus, the plate boundary is likely contained within or at the top of this low velocity zone, which potentially indicates a significant porosity and fluid content within the seismogenic zone.This work is funded by National Science Foundation Award Numbers EAR‐1520690.2021-07-2
Social media use and impact during the holiday travel planning process
Through an empirical study among holiday travellers, residing in the Former Soviet Union Republics, this paper presents a comprehensive view of role and impact of social media on the whole holiday travel planning process: Before, during and after the trip, providing insights on usage levels, scope of use, level of influence and trust. Findings suggest that social media are predominantly used after holidays for experience sharing. It is also shown that there is a strong correlation between perceived level of influence from social media and changes made in holiday plans prior to final decisions. Moreover, it is revealed that user-generated content is perceived as more trustworthy when compared to official tourism websites, travel agents and mass media advertising
Sandpiles on multiplex networks
We introduce the sandpile model on multiplex networks with more than one type
of edge and investigate its scaling and dynamical behaviors. We find that the
introduction of multiplexity does not alter the scaling behavior of avalanche
dynamics; the system is critical with an asymptotic power-law avalanche size
distribution with an exponent on duplex random networks. The
detailed cascade dynamics, however, is affected by the multiplex coupling. For
example, higher-degree nodes such as hubs in scale-free networks fail more
often in the multiplex dynamics than in the simplex network counterpart in
which different types of edges are simply aggregated. Our results suggest that
multiplex modeling would be necessary in order to gain a better understanding
of cascading failure phenomena of real-world multiplex complex systems, such as
the global economic crisis.Comment: 7 pages, 7 figure
Combinatorial Roles of Heparan Sulfate Proteoglycans and Heparan Sulfates in Caenorhabditis elegans Neural Development
Heparan sulfate proteoglycans (HSPGs) play critical roles in the development and adult physiology of all metazoan organisms. Most of the known molecular interactions of HSPGs are attributed to the structurally highly complex heparan sulfate (HS) glycans. However, whether a specific HSPG (such as syndecan) contains HS modifications that differ from another HSPG (such as glypican) has remained largely unresolved. Here, a neural model in C. elegans is used to demonstrate for the first time the relationship between specific HSPGs and HS modifications in a defined biological process in vivo. HSPGs are critical for the migration of hermaphrodite specific neurons (HSNs) as genetic elimination of multiple HSPGs leads to 80% defect of HSN migration. The effects of genetic elimination of HSPGs are additive, suggesting that multiple HSPGs, present in the migrating neuron and in the matrix, act in parallel to support neuron migration. Genetic analyses suggest that syndecan/sdn-1 and HS 6-O-sulfotransferase, hst-6, function in a linear signaling pathway and glypican/lon-2 and HS 2-O-sulfotransferase, hst-2, function together in a pathway that is parallel to sdn-1 and hst-6. These results suggest core protein specific HS modifications that are critical for HSN migration. In C. elegans, the core protein specificity of distinct HS modifications may be in part regulated at the level of tissue specific expression of genes encoding for HSPGs and HS modifying enzymes. Genetic analysis reveals that there is a delicate balance of HS modifications and eliminating one HS modifying enzyme in a compromised genetic background leads to significant changes in the overall phenotype. These findings are of importance with the view of HS as a critical regulator of cell signaling in normal development and disease
Squeezed States of the Generalized Minimum Uncertainty State for the Caldirola-Kanai Hamiltonian
We show that the ground state of the well-known pseudo-stationary states for
the Caldirola-Kanai Hamiltonian is a generalized minimum uncertainty state,
which has the minimum allowed uncertainty , where is a constant depending on the damping
factor and natural frequency. The most general symmetric Gaussian states are
obtained as the one-parameter squeezed states of the pseudo-stationary ground
state. It is further shown that the coherent states of the pseudo-stationary
ground state constitute another class of the generalized minimum uncertainty
states.Comment: RevTex4, 9 pages, no fingure; to be published in Journal of Physics
Motives for physical activity in older men and women: A twin study using accelerometer-measured physical activity
Motives for physical activity may vary considerably by age, sex, and the level of physical activity. We aimed to examine motives for physical activity in older men and women with different physical activity levels as well as whether genetic and/or environmental factors explain those motives. Finnish twins (mean age 72.9 years, 262 full twin pairs) self-reported their motives for physical activity. Time spent on moderate-to-vigorous physical activity was monitored using a hip-worn accelerometer. Comparisons between the different physical activity groups of older twins (n = 764-791/motive dimension) were analyzed using the Wald test, and effect sizes were calculated as Cohen's d. Quantitative genetic modeling was used to estimate genetic and environmental contributions. For both sexes, the most frequently reported motives for physical activity were physical fitness, health maintenance, and psychological well-being. Conforming to others' expectations was more important for men than for women (P < .001, Cohen's d = 0.38), while appearance (P = .001 Cohen's d = -0.24) and psychological well-being (P = .02, Cohen's d = -0.17) were highlighted by women. Most of the motive dimensions differed significantly between the physically active and inactive individuals. It was estimated that 5%-42% of the variation in motives was contributed by genetic factors and 58%-95% by environmental factors. The result that environmental factors contribute in a great deal to motives indicates that interventions to motivate physically inactive older individuals to be physically active can be successful. However, personalized interventions are needed because sex and the level of physical activity were found to be associated with older individuals' motives for physical activity
- …