9,724 research outputs found
Diagnostics of Coronal Magnetic Fields Through the Hanle Effect in UV and IR Lines
The plasma thermodynamics in the solar upper atmosphere, particularly in the
corona, are dominated by the magnetic field, which controls the flow and
dissipation of energy. The relative lack of knowledge of the coronal vector
magnetic field is a major handicap for progress in coronal physics. This makes
the development of measurement methods of coronal magnetic fields a high
priority in solar physics. The Hanle effect in the UV and IR spectral lines is
a largely unexplored diagnostic. We use magnetohydrodynamic (MHD) simulations
to study the magnitude of the signal to be expected for typical coronal
magnetic fields for selected spectral lines in the UV and IR wavelength ranges,
namely the H I Ly- and the He I 10830 {\AA} lines. We show that the
selected lines are useful for reliable diagnosis of coronal magnetic fields.
The results show that the combination of polarization measurements of spectral
lines with different sensitivities to the Hanle effect may be most appropriate
for deducing coronal magnetic properties from future observations.Comment: 15 pages, 5 figures, Frontiers in Astronomy and Space Sciences, 201
Selectively excited luminescence and magnetic circular dichroism of Cr4+-doped YAG and YGG
Site selective luminescence and magnetic circular dichroism experiments on Cr4+-doped yttrium aluminum garnet and yttrium gallium garnet have been made at low temperature. The spectral assignments for these near-IR lasing materials have been made using experimental data and ligand field calculations guided by the known geometry of the lattices. [S0163-1829(99)07003-4]
The virtual origin as a first-order correction for the far-field description of laminar jets
The far-field velocity and composition fields of a submerged laminar jet are known to approach a self-similar solution corresponding to the flow induced by a point source of momentum and scalar. Previous efforts to improve this far-field description have introduced a virtual origin for the streamwise coordinate to remedy the singular behavior of the self-similar solution near the jet origin. The purpose of this note is to show, by means of a perturbative analysis of the point-source solution, that this virtual origin is in fact the first-order correction to the leading-order description. The perturbative analysis, which uses the ratio x of the streamwise distance to the length of jet development as an asymptotically large quantity, also indicates that the displaced point source provides the description in the far field with small relative errors of order x-3 for the round jet and of order x-10/3 for the plane jet. The values of the virtual origin are obtained by numerical integration of the boundary-layer equations in the region of jet development, giving values that depend on the shape of the jet velocity profile at the exit
A Longitudinal Study of the Reciprocal Relationship Between Ever Smoking and Urgency in Early Adolescence
Background—Among early adolescents in the United States (U.S.), the prevalence of cigarette smoking is at its lowest level in recent decades. Nonetheless, given the risks of smoking in early development, it remains critically important to study both risk factors for smoking and risks from smoking. This longitudinal study with U.S. early adolescents examines smoking initiation and tests a model of reciprocal prediction between ever smoking and the personality trait of urgency (i.e., mood-based impulsivity), a trait that increases risk for multiple forms of dysfunction.
Methods—Participants (n=1906; 90% 10–11 years old, 50% female, 39% racial minorities at baseline) completed questionnaires 1–2 times per year starting in 5th grade and ending in 9th grade. Structural equation modeling allowed tests of bidirectional relationships between ever smoking and urgency controlling for pubertal status and negative affect at each wave.
Results—Incidence of ever smoking increased from 5% to 27% over time, with current smoking around 5% at the last wave. Urgency at each wave predicted ever smoking at the next wave above and beyond covariates and prior smoking (all p \u3c .01). Likewise, with one exception, ever smoking predicted an increase in urgency at the subsequent wave above and beyond covariates and prior urgency (all p \u3c .05).
Conclusion—Results show that risk for smoking increases with higher levels of urgency and urgency increases secondary to engagement in smoking. Future work should therefore explore urgency as a point of prevention for smoking and smoking cessation as a means to mitigate mood-based impulsivity
Determining significant parameters on health and well-being of building occupants towards re-engineered inclusive environment
People spend over 90% of their time in the buildings. A building is a place where people are spending
more time doing activities, thus an inclusive environment of the buildings is very important to ensure
that people are having a healthy life. An inclusive environment is important for the well-being of
building occupants. Indoor environmental quality is one of the essential elements in creating an
inclusive environment in which a poor quality of indoor environment affects the health of the
occupants both physically and mentally, their performance, productivity, comfort, satisfaction, and
well-being. Even though people are towards creating an inclusive environment but it is a limited study
on the parameters of the inclusive environment. Thus, this paper is to study the parameters of the
inclusive environment by focused on the element of the indoor environmental quality for building
occupants based on literature reviews of articles between the year 2006 and 2016. Based on the
content analysis, it has been discovered that there are various parameters of an inclusive
environment which are visual comfort, thermal comfort, acoustic comfort, indoor air quality, buildings
factors, occupants’ factors, and climate condition factors. The parameters can be very useful as
guidelines and development of policy in providing inclusive environment for the healthy lifestyle of
building occupants
Determining significant parameters on health and well-being of building occupants towards re-engineered inclusive environment
People spend over 90% of their time in the buildings. A building is a place where people are spending
more time doing activities, thus an inclusive environment of the buildings is very important to ensure
that people are having a healthy life. An inclusive environment is important for the well-being of
building occupants. Indoor environmental quality is one of the essential elements in creating an
inclusive environment in which a poor quality of indoor environment affects the health of the
occupants both physically and mentally, their performance, productivity, comfort, satisfaction, and
well-being. Even though people are towards creating an inclusive environment but it is a limited study
on the parameters of the inclusive environment. Thus, this paper is to study the parameters of the
inclusive environment by focused on the element of the indoor environmental quality for building
occupants based on literature reviews of articles between the year 2006 and 2016. Based on the
content analysis, it has been discovered that there are various parameters of an inclusive
environment which are visual comfort, thermal comfort, acoustic comfort, indoor air quality, buildings
factors, occupants’ factors, and climate condition factors. The parameters can be very useful as
guidelines and development of policy in providing inclusive environment for the healthy lifestyle of
building occupants
Acute exposure of primary rat soleus muscle to zilpaterol HCl (β2 adrenergic agonist), TNFα, or IL-6 in culture increases glucose oxidation rates independent of the impact on insulin signaling or glucose uptake
Recent studies show that adrenergic agonists and inflammatory cytokines can stimulate skeletal muscle glucose uptake, but it is unclear if glucose oxidation is similarly increased. Thus, the objective of this study was to determine the effects of ractopamine HCl (β1 agonist), zilpaterol HCl (β2 agonist), TNFα, and IL-6 on glucose uptake and oxidation rates in unstimulated and insulin-stimulated soleus muscle strips from adult Sprague-Dawley rats. Effects on phosphorylation of Akt (phospho-Akt), p38 MAPK (phospho-p38), and p44/42 MAPK (phospho-p44/42) was also determined. Incubation with insulin increased (P \u3c 0.05) glucose uptake by ~47%, glucose oxidation by ~32%, and phospho-Akt by ~238%. Insulin also increased (P \u3c 0.05) phospho-p38, but only after 2 hours in incubation. Muscle incubated with β2 agonist alone exhibited ~20% less (P \u3c 0.05) glucose uptake but ~32% greater (P \u3c 0.05) glucose oxidation than unstimulated muscle. Moreover, co-incubation with insulin + β2 agonist increased (P \u3c 0.05) glucose oxidation and phospho-Akt compared to insulin alone. Conversely, β1 agonist did not appear to affect basal or insulin-stimulated glucose metabolism, and neither β agonist affected phospho-p44/42. TNFα and IL-6 increased (P \u3c 0.05) glucose oxidation by ~23% and ~33%, respectively, in the absence of insulin. This coincided with increased (P \u3c 0.05) phospho-p38 and phospho-p44/42 but not phospho-Akt. Furthermore, co-incubation of muscle with insulin + either cytokine yielded glucose oxidation rates that were similar to insulin alone, despite lower (P \u3c 0.05) phospho-Akt. Importantly, cytokine-mediated increases in glucose oxidation rates were not concomitant with greater glucose uptake. These results show that acute β2 adrenergic stimulation, but not β1 stimulation, directly increases fractional glucose oxidation in the absence of insulin and synergistically increases glucose oxidation when combined with insulin. The cytokines, TNFα and IL-6, likewise directly increased glucose oxidation in the absence of insulin, but were not additive in combination with insulin and in fact appeared to disrupt Akt-mediated insulin signaling. Rather, cytokines appear to be acting through MAPKs to elicit effects on glucose oxidation. Regardless, stimulation of glucose oxidation by these key stress factors did not rely upon greater glucose uptake, which may promote metabolic efficiency during acute stress by increasing fractional glucose oxidation without increasing total glucose consumption by muscle
- …