1,228 research outputs found
Bounds on \"{U}bercrossing and Petal Numbers for Knots
An -crossing is a point in the projection of a knot where strands
cross so that each strand bisects the crossing. An \"ubercrossing projection
has a single -crossing and a petal projection has a single -crossing such
that there are no loops nested within others. The \"ubercrossing number,
, is the smallest for which we can represent a knot with
a single -crossing. The petal number is the number of loops in the minimal
petal projection. In this paper, we relate the \"{u}bercrossing number and
petal number to well-known invariants such as crossing number, bridge number,
and unknotting number. We find that the bounds we have constructed are tight
for -torus knots. We also explore the behavior of \"{u}bercrossing
number under composition.Comment: 13 pages, 8 figure
Analysis of Rediscovered Data from Apollo 17's Lunar Seismic Profiling Experiment: Evidence for Events Associated with Sunrise
No abstract availabl
Gene Expression Contributes to the Recent Evolution of Host Resistance in a Model Host Parasite System
Heritable population differences in immune gene expression following infection can reveal mechanisms of host immune evolution. We compared gene expression in infected and uninfected threespine stickleback (Gasterosteus aculeatus) from two natural populations that differ in resistance to a native cestode parasite, Schistocephalus solidus. Genes in both the innate and adaptive immune system were differentially expressed as a function of host population, infection status, and their interaction. These genes were enriched for loci controlling immune functions known to differ between host populations or in response to infection. Coexpression network analysis identified two distinct processes contributing to resistance: parasite survival and suppression of growth. Comparing networks between populations showed resistant fish have a dynamic expression profile while susceptible fish are static. In summary, recent evolutionary divergence between two vertebrate populations has generated population-specific gene expression responses to parasite infection, affecting parasite establishment and growth
A Comparison of Muscle Recruitment Across Three Straight-Legged, Hinge-Pattern Resistance Training Exercises
International Journal of Exercise Science 16(4): 12-22, 2023. Hinge exercises are critical to building a balanced resistance training program in concert with ‘knee-dominant’ (e.g., squat, lunge) exercises. Biomechanical differences between various straight-legged hinge (SLH) exercises may alter muscle activation. For example, a Romanian deadlift (RDL) is a closed-chain SLH, while a reverse hyperextension (RH) is open-chain. Likewise, the RDL offers resistance via gravity while the cable pull-through (CP) offers redirected-resistance through a pulley. A deeper understanding of the potential impact of these biomechanical differences between these exercises may improve their application to specific goals. Participants completed repetition-maximum (RM) testing on the RDL, RH, and CP. On a follow-up visit, surface electromyography of the longissimus, multifidus, gluteus maximus, semitendinosus, and biceps femoris, muscles that contribute to lumbar/hip extension, was recorded. After a warm-up, participants completed maximal voluntary isometric contractions (MVICs) in each muscle. They then completed five repetitions of the RDL, RH, and CP at 50% of estimated one RM. Testing order was randomized. A one-way, repeated-measures ANOVA test was used in each muscle to compare activation (%MVIC) across the three exercises. Shifting from a gravity- (RDL) to a redirected-resistance (CP) SLH significantly decreased activation in the longissimus (-11.0%), multifidus (-14.1%), biceps femoris (-13.1%), and semitendinosus (-6.8%). Alternately, changing from a closed- (RDL) to an open-chain (RH) SLH significantly increased activation in the gluteus maximus (+19.5%), biceps femoris (+27.9%), and semitendinosus (+18.2). Alterations in the execution of a SLH can change muscle activation in lumbar/hip extensors
GluN2A NMDA Receptor Enhancement Improves Brain Oscillations, Synchrony, and Cognitive Functions in Dravet Syndrome and Alzheimer's Disease Models.
NMDA receptors (NMDARs) play subunit-specific roles in synaptic function and are implicated in neuropsychiatric and neurodegenerative disorders. However, the in vivo consequences and therapeutic potential of pharmacologically enhancing NMDAR function via allosteric modulation are largely unknown. We examine the in vivo effects of GNE-0723, a positive allosteric modulator of GluN2A-subunit-containing NMDARs, on brain network and cognitive functions in mouse models of Dravet syndrome (DS) and Alzheimer's disease (AD). GNE-0723 use dependently potentiates synaptic NMDA receptor currents and reduces brain oscillation power with a predominant effect on low-frequency (12-20 Hz) oscillations. Interestingly, DS and AD mouse models display aberrant low-frequency oscillatory power that is tightly correlated with network hypersynchrony. GNE-0723 treatment reduces aberrant low-frequency oscillations and epileptiform discharges and improves cognitive functions in DS and AD mouse models. GluN2A-subunit-containing NMDAR enhancers may have therapeutic benefits in brain disorders with network hypersynchrony and cognitive impairments
Climate Change Adaptation in Post-Disaster Recovery Processes: Flood-Affected Communities in Cambodia and Fiji
By adopting an integrated and participatory action-research approach, this project explores how rural
communities living in flood-prone river basins of Cambodia and Fiji respond to increasing variability
of flood incidences and other natural hazards under the influence of climate change and other risk factors, such as hydro-electric power development, forest conversion and environmental degradation.
Particular emphasis is placed on risk perceptions and adaptive strategies of individuals, families and social groups with regard to regular and catastrophic floods and how the livelihoods of vulnerable groups are affected by floods and other disasters. Our research approach integrates the food, water and energy security nexus with the rural livelihood framework.
The objectives of the project are to (1) identify the spatial extent and dynamics of flood hazards as a result of multiple risk factors; (2) determine the various factors that can enhance resilience and adaptive capacities of flood-affected communities in a changing environment, and (3) provide examples of successful community-based flood management and climate change adaptation that can serve as best-practice models for other flood affected communities in the Asia-Pacific region
Direct visualization of the charge transfer in Graphene/-RuCl heterostructure
We investigate the electronic properties of a graphene and -ruthenium
trichloride (hereafter RuCl) heterostructure, using a combination of
experimental and theoretical techniques. RuCl is a Mott insulator and a
Kitaev material, and its combination with graphene has gained increasing
attention due to its potential applicability in novel electronic and
optoelectronic devices. By using a combination of spatially resolved
photoemission spectroscopy, low energy electron microscopy, and density
functional theory (DFT) calculations we are able to provide a first direct
visualization of the massive charge transfer from graphene to RuCl, which
can modify the electronic properties of both materials, leading to novel
electronic phenomena at their interface. The electronic band structure is
compared to DFT calculations that confirm the occurrence of a Mott transition
for RuCl. Finally, a measurement of spatially resolved work function allows
for a direct estimate of the interface dipole between graphene and RuCl.
The strong coupling between graphene and RuCl could lead to new ways of
manipulating electronic properties of two-dimensional lateral heterojunction.
Understanding the electronic properties of this structure is pivotal for
designing next generation low-power opto-electronics devices
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Anti-drug Antibody Responses Impair Prophylaxis Mediated by AAV-Delivered HIV-1 Broadly Neutralizing Antibodies
Adeno-associated virus (AAV) delivery of potent and broadly neutralizing antibodies (bNAbs is a promising approach for the prevention of HIV-1 infection. The immunoglobulin G (IgG)1 subtype is usually selected for this application, because it efficiently mediates antibody effector functions and has a somewhat longer half-life. However, the use of IgG1-Fc has been associated with the generation of anti-drug antibodies (ADAs) that correlate with loss of antibody expression. In contrast, we have shown that expression of the antibody-like molecule eCD4-Ig bearing a rhesus IgG2-Fc domain showed reduced immunogenicity and completely protected rhesus macaques from simian-HIV (SHIV)-AD8 challenges. To directly compare the performance of the IgG1-Fc and the IgG2-Fc domains in a prophylactic setting, we compared AAV1 expression of rhesus IgG1 and IgG2 forms of four anti-HIV bNAbs: 3BNC117, NIH45-46, 10-1074, and PGT121. Interestingly, IgG2-isotyped bNAbs elicited significantly lower ADA than their IgG1 counterparts. We also observed significant protection from two SHIV-AD8 challenges in macaques expressing IgG2-isotyped bNAbs, but not from those expressing IgG1. Our data suggest that monoclonal antibodies isotyped with IgG2-Fc domains are less immunogenic than their IgG1 counterparts, and they highlight ADAs as a key barrier to the use of AAV1-expressed bNAbs
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