3,236 research outputs found
Building a Pathway to Engineering for Our Daughters – Brick by Brick
As a father of young elementary and middle school-aged kids, I’m also curious to know exactly how my undergrad students came to be interested in mechanical engineering. An exchange with a UCF student might go like this: “You did a great job on the exam. Congrats! By the way, how did you get interested in mechanical engineering, anyway?” I mentally log the answers for my kids’ future benefit
Homeschooled Students Bring Own Set of Skills to University Campuses
Key questions always loom large for parents of homeschooled, college-bound students, such as: “What happens when my child actually gets to the university level? Will they be able to keep up?
Basketball\u27s On-the-Court Situations, Strategies Often Extend to Workplace
To me, basketball has always been THE sport of team sports because of its vibrancy, its thrills, its intense moments, its nonstop action and its sheer power. Only a few get to live out their hoop dreams, however, and play at the highest professional level
There\u27s More Than $ Involved When it Comes to Understanding Costs of Fracking
Several of society’s next grand challenges relate to the production of electrical energy
Is it Time to Level the Playing Field for College Athletes?
I love college sports. I’ve got the Knights, Yellow Jackets, Tar Heels, Hoyas, Maroon Tigers – you name it. If I can catch a game, I will
Submillimeter to centimeter excess emission from the Magellanic Clouds. II. On the nature of the excess
Dust emission at submm to cm wavelengths is often simply the Rayleigh-Jeans
tail of dust particles at thermal equilibrium and is used as a cold mass tracer
in various environments including nearby galaxies. However, well-sampled
spectral energy distributions of the nearby, star-forming Magellanic Clouds
have a pronounced (sub-)millimeter excess (Israel et al., 2010). This study
attempts to confirm the existence of such a millimeter excess above expected
dust, free-free and synchrotron emission and to explore different possibilities
for its origin. We model NIR to radio spectral energy distributions of the
Magellanic Clouds with dust, free-free and synchrotron emission. A millimeter
excess emission is confirmed above these components and its spectral shape and
intensity are analysed in light of different scenarios: very cold dust, Cosmic
Microwave Background (CMB) fluctuations, a change of the dust spectral index
and spinning dust emission. We show that very cold dust or CMB fluctuations are
very unlikely explanations for the observed excess in these two galaxies. The
excess in the LMC can be satisfactorily explained either by a change of the
spectral index due to intrinsic properties of amorphous grains, or by spinning
dust emission. In the SMC however, due to the importance of the excess, the
dust grain model including TLS/DCD effects cannot reproduce the observed
emission in a simple way. A possible solution was achieved with spinning dust
emission, but many assumptions on the physical state of the interstellar medium
had to be made. Further studies, using higher resolution data from Planck and
Herschel, are needed to probe the origin of this observed submm-cm excess more
definitely. Our study shows that the different possible origins will be best
distinguished where the excess is the highest, as is the case in the SMC.Comment: 7 pages, 6 figures; accepted in A&
Heart failure with preserved ejection fraction (HFpEF) pathophysiology study (IDENTIFY-HF): does increased arterial stiffness associate with HFpEF, in addition to ageing and vascular effects of comorbidities? Rationale and design
Aims: There has been a paradigm shift proposing that comorbidities are a major contributor towards the heart failure with preserved ejection fraction (HFpEF) syndrome. Furthermore, HFpEF patients have abnormal macrovascular and microvascular function, which may significantly contribute towards altered ventricular-vascular coupling in these patients. The IDENTIFY-HF study will investigate whether gradually increased arterial stiffness (in addition to ageing) as a result of increasing common comorbidities, such as hypertension and diabetes, is associated with HFpEF.
Methods and analysis: In our observational study, arterial compliance and microvascular function will be assessed in five groups (Groups A to E) of age, sex and body mass index matched subjects (age ≥70 years in all groups):
Group A; normal healthy volunteers without major comorbidities such as hypertension and diabetes mellitus (control). Group B; patients with hypertension without diabetes mellitus or heart failure (HF). Group C; patients with hypertension and diabetes mellitus without HF. Group D; patients with HFpEF. Group E; patients with heart failure and reduced ejection fraction (parallel group). Vascular function and arterial compliance will be assessed using pulse wave velocity, as the primary outcome measure. Further outcome measures include cutaneous laser Doppler flowmetry as a measure of endothelial function, transthoracic echocardiography and exercise tolerance measures. Biomarkers include NT-proBNP, high-sensitivity troponin T, as well as serum galectin-3 as a marker of fibrosis.
Ethics and dissemination: The study was approved by the regional research ethics committee (REC), West Midland and Black Country 17/WM/0039, UK, and permission to conduct the study in the hospital was also obtained from the RDI, UHCW NHS Trust. The results will be published in peer-reviewed journals and presented in local, national and international medical society meetings.
Trial registration number: NCT0318683
A fast spinning magnetic white dwarf in the double degenerate, super-Chandrasekhar system NLTT 12758
We present an analysis of the close double degenerate NLTT 12758, which is comprised of
a magnetic white dwarf with a field of about 3.1 MG and an apparently non-magnetic white
dwarf. We measured an orbital period of 1.154 d and found that the magnetic white dwarf is
spinning around its axis with a period of 23 min. An analysis of the atmospheric parameters
has revealed that the cooling ages of the two white dwarfs are comparable, suggesting that
they formed within a short period of time from each other. Our modelling indicates that the
non-magnetic white dwarf is more massive (M = 0.83 M) than its magnetic companion
(M = 0.69 M) and that the total mass of the system is higher than the Chandrasekhar mass.
Although the stars will not come into contact over a Hubble time, when they do come into
contact, dynamically unstable mass transfer will take place leading to either an accretion
induced collapse into a rapidly spinning neutron star or a Type Ia supernova
First Science Observations with SOFIA/FORCAST: Properties of Intermediate-Luminosity Protostars and Circumstellar Disks in OMC-2
We examine eight young stellar objects in the OMC-2 star forming region based
on observations from the SOFIA/FORCAST early science phase, the Spitzer Space
Telescope, the Herschel Space Observatory, 2MASS, APEX, and other results in
the literature. We show the spectral energy distributions of these objects from
near-infrared to millimeter wavelengths, and compare the SEDs with those of
sheet collapse models of protostars and circumstellar disks. Four of the
objects can be modelled as protostars with infalling envelopes, two as young
stars surrounded by disks, and the remaining two objects have double-peaked
SEDs. We model the double-peaked sources as binaries containing a young star
with a disk and a protostar. The six most luminous sources are found in a dense
group within a 0.15 x 0.25 pc region; these sources have luminosities ranging
from 300 L_sun to 20 L_sun. The most embedded source (OMC-2 FIR 4) can be fit
by a class 0 protostar model having a luminosity of ~50 L_sun and mass infall
rate of ~10^-4 solar masses per year.Comment: Accepted by ApJ Letter
Driving calmodulin protein towards conformational shift by changing ionization states of select residues
Proteins are complex systems made up of many conformational sub-states which are mainly determined by the folded structure. External factors such as solvent type, temperature, pH and ionic strength play a very important role in the conformations sampled by proteins. Here we study the conformational multiplicity of calmodulin (CaM) which is a protein that plays an important role in calcium signaling pathways in the eukaryotic cells. CaM can bind to a variety of other proteins or small organic compounds, and mediates different physiological processes by activating various enzymes. Binding of calcium ions and proteins or small organic molecules to CaM induces large conformational changes that are distinct to each interacting partner. In particular, we discuss the effect of pH variation on the conformations of CaM. By using the pKa values of the charged residues as a basis to assign protonation states, the conformational changes induced in CaM by reducing the pH are studied by molecular dynamics simulations. Our current view suggests that at high pH, barrier crossing to the compact form is prevented by repulsive electrostatic interactions between the two lobes. At reduced pH, not only is barrier crossing facilitated by protonation of residues, but also conformations which are on average more compact are attained. The latter are in accordance with the fluorescence resonance energy transfer experiment results of other workers. The key events leading to the conformational change from the open to the compact conformation are (i) formation of a salt bridge between the N-lobe and the linker, stabilizing their relative motions, (ii) bending of the C-lobe towards the N-lobe, leading to a lowering of the interaction energy between the two-lobes, (iii) formation of a hydrophobic patch between the two lobes, further stabilizing the bent conformation by reducing the entropic cost of the compact form, (iv) sharing of a Ca+2 ion between the two lobes
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