718 research outputs found
Physiological and Molecular Responses of Eurythermal and Stenothermal Populations of \u3ci\u3eZostera Marina\u3c/i\u3e L (Eelgrass) to Climate Change
As CO2 levels in Earth’s atmosphere and oceans steadily rise, varying organismal responses may produce ecological losers and winners. Increased ocean CO2 can enhance seagrass productivity and thermal tolerance, providing some compensation for climate warming. However, the consistency of this CO2 effect across populations of cosmopolitan species such as Zostera marina L. (eelgrass) remains largely unknown. This study analyzed whole-plant performance metabolic profiles and gene expression patterns of distinct eelgrass populations in response to CO2 enrichment. Populations were transplanted from Nisqually Landing and Dumas Bay, two cold water environments in Puget Sound, WA (USA) that rarely experience summer water temperatures above 15° C, and one population from South Bay, VA (USA) that frequently experiences summer heat waves exceeding 25° C. All three populations were grown in outdoor aquaria and exposed to five different CO2 concentrations, under natural light and ambient water temperature of southeast Virginia, for 18 months. The three eelgrass populations showed similar instantaneous metabolic responses to CO2 treatments. However, only eelgrass from South Bay, VA and Dumas Bay, WA exhibited physiological stimulation to seasonally increasing temperature under elevated CO2 treatments, increasing shoot numbers, plant size, and leaf growth. The plants from Nisqually Landing, WA were unable to survive the warm summer water temperature even in the presence of high CO2 concentrations. Metabolomic profiling revealed differences among CO2 treatments and eelgrass populations. CO2 enrichment increased the abundance of Calvin Cycle and nitrogen assimilation metabolites while suppressing the abundance of stress-related metabolites. However, target genes involved in carbohydrate fixation, photosynthesis and proteins that function as molecular chaperones did not respond to CO2 enrichment even though they changed through in response to light and temperature. Transcriptome profiles by themselves did not predict how gene expression translates into physiological and metabolic consequences under high CO2 conditions. The differential response among eelgrass populations suggest that seagrass populations will respond variably to increasing CO2 concentrations in which some eelgrass phenotypes may be better suited to cope with an increasingly hot and sour sea than others
Adjuvants : an essential component of neisseria vaccines
Adjuvants may be classified into delivery systems and immune potentiator or modulator molecules based on their mechanism of action. Neisseria vaccines containing traditional adjuvants such as aluminium salts have existed for long time, but meningitis caused by Neisseria meningitidis serogroups, particularly serogroup B, continues to be a global health problem. Novel strategies have applied in silico and recombinant technologies to develop "universal" antigens (e.g. proteins, peptides and plasmid DNA) for vaccines, but these antigens have been shown to be poorly immunogenic even when alum adjuvanted, implying a need for better vaccine design. In this work we review the use of natural, detoxified, or synthetic molecules in combination with antigens to activate the innate immune system and to modulate the adaptive immune responses. In the main, antigenic and imune potentiator signals are delivered using nano-, micro-particles, alum, or emulsions. The importance of interaction between adjuvants and antigens to activate and target dendritic cells, the bridge between the innate and adaptive immune systems, will be discussed. In addition, nasal vaccine strategies based on the development of mucosal adjuvants and Neisseria derivatives to eliminate the pathogen at the site of infection provide promising adjuvants effective not only against respiratory pathogens, but also against pathogens responsible for enteric and sexually transmitted diseases
Glueball Regge trajectories from gauge/string duality and the Pomeron
The spectrum of light baryons and mesons has been reproduced recently by
Brodsky and Teramond from a holographic dual to QCD inspired in the AdS/CFT
correspondence. They associate fluctuations about the AdS geometry with four
dimensional angular momenta of the dual QCD states. We use a similar approach
to estimate masses of glueball states with different spins and their
excitations. We consider Dirichlet and Neumann boundary conditions and find
approximate linear Regge trajectories for these glueballs. In particular the
Neumann case is consistent with the Pomeron trajectory.Comment: In this revised version we made some additional remarks on the text.
We also included 2 more references. The glueball spectrum and Regge
trajectories are unchanged. 10 pages, 2 eps figure
Baryon Masses and Wilson Loops for Fractional D3-Branes on the Resolved Conifold
We study the IR dynamics of the type IIB supergravity solution describing N
D3-branes and M fractional D3-branes on the resolved conifold. The baryon mass
and the tension of domain wall in the dual gauge theory are evaluated and
compared with those for the deformed conifold. The IR behavior of the solution
for the general conifold is also discussed. We show that the area law behavior
of the Wilson loop is attributed to the existence of the locus in the IR where
the D3-brane charge vanishes.Comment: 13 pages, LaTeX2e, no figure
On a Holographic Model for Confinement/Deconfinement
We study the thermodynamics of the hard wall model, which consists in the
introduction of an infrared cut-off in asymptotically AdS spaces. This is a toy
model for confining backgrounds in the context of the gauge/gravity
correspondence. We use holographic renormalization and reproduce the existence
of a Hawking Page phase transition recently discussed by Herzog. We also show
that the entropy jumps from to , which reinforces the interpretation
of this transition as the gravity dual of confinement/deconfinement. We also
show that similar results hold for the phenomenologically motivated soft wall
model, underlining the potential universality of our analysis.Comment: 14 pages. V2: We included a new section discussing the soft wall
model and new references. V3: We clarified some points and updated the
references. Results unchanged. Version published in PR
A new paradigm in respiratory hygiene: modulating respiratory secretions to contain cough bioaerosol without affecting mucus clearance
<p>Abstract</p> <p>Background</p> <p>Several strategies and devices have been designed to protect health care providers from acquiring transmissible respiratory diseases while providing care. In modulating the physical characteristics of the respiratory secretions to minimize the aerosolization that facilitates transmission of airborne diseases, a fundamental premise is that the prototype drugs have no adverse effect on the first line of respiratory defense, clearance of mucus by ciliary action.</p> <p>Methods</p> <p>To assess and demonstrate the primary mechanism of our mucomodulators (XLs), we have built our evidence moving from basic laboratory studies to an <it>ex-vivo </it>model and then to an <it>in-vivo </it>large animal model. We exposed anesthetized dogs without hypersecretion to different dose concentrations of aerosolized XL "B", XL "D" and XL "S". We assessed: cardio-respiratory pattern, tracheal mucus clearance, airway patency, and mucus viscoelastic changes.</p> <p>Results</p> <p>Exposure of frog palate mucus to XLs did not affect the clearance of mucus by ciliary action. Dogs maintained normal cardio-respiratory pattern with XL administration. Tracheal mucociliary clearance in anesthetized dogs indicated a sustained 40% mean increase. Tracheal mucus showed increased filance, and there was no mucus retention in the airways.</p> <p>Conclusion</p> <p>The <it>ex-vivo </it>frog palate and the <it>in-vivo </it>mammalian models used in this study, appear to be appropriate and complement each other to better assess the effects that our mucomodulators exert on the mucociliary clearance defence mechanism. The physiological function of the mucociliary apparatus was not negatively affected in any of the two epithelial models. Airway mucus crosslinked by mucomodulators is better cleared from an intact airway and normally functioning respiratory system, either due to enhanced interaction with cilia or airflow-dependent mechanisms. Data obtained in this study allow us to assure that we have complied with the fundamental requirement criteria established in the initial phase of developing the concept of mucomodulation: Can we modulate the physical characteristics of the respiratory secretions to reduce aerosolization without affecting normal mucociliary clearance function, or even better improving it?</p
Transmitting Digital Lutherie Knowledge: The Rashomon Effect for DMI Designers
As the field around computer-mediated musical interaction drives attention to its sociotechnical, political and epistemological exigencies, it becomes important to be guided by disability studies, and for researchers and designers of accessible digital musical instruments (ADMIs) to foreground the lived experience of disabled musicians. This resonates with the movement to promote disability justice in HCI. In this paper, we introduce a case study of the design of a string-less guitar, which was developed in collaboration with a guitarist who lost his ability to play due to impairment. We present this work as an exploration of the Rashomon effect, a term that refers to the phenomenon of multiple witnesses describing the same event from their own perspective. We argue that the Rashomon effect is a useful way to explore how digital musical instrument (DMI) designers respond to NIME's interdisciplinarity, and to reflect on how we produce and transmit knowledge within our field
Metabolic Profiling Reveals Biochemical Pathways Responsible for Eelgrass Response to Elevated CO\u3csub\u3e2\u3c/sub\u3e and Temperature
As CO2 levels in Earth’s atmosphere and oceans steadily rise, varying organismal responses may produce ecological losers and winners. Increased ocean CO2 can enhance seagrass productivity and thermal tolerance, providing some compensation for climate warming. However, the metabolic shifts driving the positive response to elevated CO2 by these important ecosystem engineers remain unknown. We analyzed whole-plant performance and metabolic profiles of two geographically distinct eelgrass (Zostera marina L.) populations in response to CO2 enrichment. In addition to enhancing overall plant size, growth and survival, CO2 enrichment increased the abundance of Calvin Cycle and nitrogen assimilation metabolites while suppressing the abundance of stress-related metabolites. Overall metabolome differences between populations suggest that some eelgrass phenotypes may be better suited than others to cope with an increasingly hot and sour sea. Our results suggest that seagrass populations will respond variably, but overall positively, to increasing CO2 concentrations, generating negative feedbacks to climate change
Hagedorn transition for strings on pp-waves and tori with chemical potentials
It has been conjectured that string theory in a pp-wave background is dual to
a sector of N=4 supersymmetric Yang-Mills theory.
We study the Hagedorn transition for free strings in this background. We find
that the free energy at the transition point is finite suggesting a
confinement/deconfinement transition in the gauge theory. In the limit of
vanishing mass parameter the free energy matches that of free strings on an
8-torus with momentum/winding chemical potential. The entropy in the
microcanonical ensemble with fixed energy and fixed momentum/winding is
computed in each case.Comment: 15 pages, latex, references added and minor correction
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