•A new ratiometric pressure readout approach is proposed.•A highly sensitive ratiometric manometer is described.•Cr3+ concentration modifies the crystal field strength.•LMTO:Cr3+ allows for ...temperature invariant pressure readout.
The dependence of the spectroscopic properties of the phosphor on the applied pressure enables the development of luminescent manomenters that allow remote readout and imaging of the pressure. Although the most widely used manometers for years have been those using pressure-induced spectral shift of the emission band, their main limitations are relatively low sensitivity for spectrally narrow emission lines or low readout precision for broadband phosphors. Taking advantage of the benefits of both these approaches, this paper proposes a ratiometric pressure-readout strategy that exploits spectral shift of the 4T2→4A2 emission band of Cr3+ ions in Li2Mg3TiO6. The luminescent manometer developed in this way is characterized by a linear dependence of LIR on pressure in the range of 0–7.75 GPa pressure range and a relative sensitivity of SR = 4.7 %/GPa. Importantly, this manometer is characterized by insensitivity to temperature changes in the 123–563 K. This novel approach will allow the development of a new group of highly sensitive luminescent manometers.
To examine the longitudinal associations between different physical activity (PA) intensities and cardiometabolic risk factors among a sample of Canadian youth.
The findings are based on a 2-year ...prospective cohort study in a convenience sample of 315 youth aged 9-15 years at baseline from rural and urban schools in Alberta, Canada. Different intensities (light, moderate and vigorous) of PA were objectively assessed with Actical accelerometers. The main outcome measures were body mass index (BMI) z-score, waist circumference, cardiorespiratory fitness and systolic blood pressure at 2-year-follow-up and conditional BMI z-score velocity. A series of linear regression models were conducted to investigate the associations after adjusting for potential confounders.
At follow-up, cardiorespiratory fitness increased (quartile 1 vs quartile 4=43.3 vs 50.2; P(trend)<0.01) and waist circumference decreased (quartile 1 vs quartile 4=79.0 vs 72.6; P(trend)=0.04; boys only) in a dose-response manner across quartiles of baseline vigorous-intensity PA. A similar trend was observed for systolic blood pressure (quartile 1 vs quartile 4=121.8 vs 115.3; P(trend)=0.07; boys only). Compared with quartile 1 of vigorous-intensity PA, BMI z-score at follow-up and conditional BMI z-score velocity were significantly lower in the quartile 2 and 3 (P<0.05). Waist circumference at follow-up also decreased (quartile 1 vs quartile 4=75.3 vs 73.8; P(trend)=0.04) across quartiles of baseline moderate-intensity PA.
Time spent in vigorous-intensity PA was associated with several positive health outcomes 2 years later. These findings suggest that high-intensity activities in youth help to reduce the risk for several chronic diseases.
Luminescent manometry enables remote pressure readout with unprecedented spatial and pressure resolution. The need to image pressure in a temperature-invariant manner imposes the search for new ...solutions that offer such capabilities. In this study, we present an approach that enables remote pressure sensing using the luminescence kinetics of Mn4+ ions in SrGdAlO4. The uniqueness of this solution is related to the pressure induced prolongation of the lifetime of the 2E level of Mn4+ ions resulting from a change in the covalency of the Mn4+–O2− bond. Taking the advantage of this effect, the luminescence decay time was increased from 1.44 ms to 2.14 ms when the pressure was changed from ambient to 7.6 GPa. This allowed the development of a luminescent manometer with a maximum relative sensitivity of 7.85%/GPa at 3 GPa and sensitivities above SR > 5%/GPa in the pressure range of 1–7.6 GPa. Moreover, in the temperature range of 260–365 K, the lifetime value was independent of temperature changes, enabling a temperature invariant manometric factor of 134.
Although lifetime-based luminescent manometers exploiting the luminescence kinetics of Mn4+ ions exhibit remarkably attractive manometric performance, the number of studies reported in the literature ...devoted to this area is relatively small. Given that this type of manometer can exhibit very high sensitivity over a limited pressure range, in-depth studies on the correlation of the structure with the manometric properties of such pressure gauges are required to enable the design of manometers with predefined sensing performance. In response to these requirements, the present work investigates the spectroscopic properties of a new promising inorganic phosphor, i.e. K2Ge4O9:Mn4+, measured as a function of pressure and temperature. As is shown, the spectral shift of the Mn4+ R-line, the ratio of its emission intensity to phonon-progression bands, and the luminescence kinetics of the 2E state can be used for remote pressure readout, with sensitivities of 0.59 nm GPa−1, SR = 21.7%/Gpa and 12%/Gpa, respectively. Notably, the developed manometer shows the highest sensitivity in the lifetime-based mode reported so far for pressure values above 2 Gpa. Furthermore, the considerable thermal sensitivity of the narrow emission line of Mn4+ ions (R-line) in the K2Ge4O9:0.1% Mn4+ material, combined with its minimal shift under pressure for pressures below 1 GPa allows for the utilization of this phosphor as a luminescent sensor capable of concurrently measuring both pressure and temperature.
A four-parameter family of orthogonal polynomials in two discrete variables is defined for a weight function of basic hypergeometric type. The polynomials, which are expressed in terms of univariate ...big
q-Jacobi polynomials, form an extension of Dunkl’s bivariate (little)
q-Jacobi polynomials C.F. Dunkl, Orthogonal polynomials in two variables of
q
-Hahn and
q
-Jacobi type, SIAM J. Algebr. Discrete Methods 1 (1980) 137–151. We prove orthogonality property of the new polynomials, and show that they satisfy a three-term relation in a vector-matrix notation, as well as a second-order partial
q-difference equation.
The aim of this study was to determine the relationship between the trajectories of weight gain and systolic blood pressure (SBP) in youth.
Annual surveys of anthropometry, fitness, SBP, and its ...determinants (cardiac output, systemic vascular resistance, and arterial compliance) were conducted in youth (aged 5 to 19 years) in a school-based setting between 2004 and 2006. Children were stratified according to change in body mass index (BMI) over time.
Within the entire cohort (
n = 2089), mean SBP (121 ± 16 SD
v 112 ± 15 SD mm Hg;
P < .01) and the prevalence of high blood pressure (48%
v 18%,
P < .01) were significantly higher and fitness levels were lower (
P < .01) in obese children, relative to healthy-weight peers. After 2 years of follow-up, despite similar SBP and BMI at baseline, the average change in SBP was ∼4.5-fold greater in children with the largest increase in BMI, relative to children who experienced minimal weight gain. This group also experienced a significantly greater increase in stroke volume (
P < .05), while the change in heart rate, arterial compliance, and systemic vascular resistance was comparable with that of children who experienced minimal weight gain. Multiple linear regression analysis revealed that SBP increased 0.77 mm Hg for every kilogram of weight gain over a period of 2 years (
P < .01).
Overweight and disproportionate weight gain in children are associated with elevated SBP. These data support the need for interventions to prevent excessive weight gain and obesity in children and adolescents.
Connection coefficients between the two-variable Bernstein and Jacobi polynomial families on the triangle are given explicitly as evaluations of two-variable Hahn polynomials. Dual two-variable ...Bernstein polynomials are introduced. Explicit formula in terms of two-variable Jacobi polynomials and a recurrence relation are given.
Luminescent manometry enables remote pressure readout with unprecedented spatial and pressure resolution. The need to image pressure in a temperature-invariant manner imposes the search for new ...solutions that offer such capabilities. In this study, we present an approach that enables remote pressure sensing using the luminescence kinetics of Mn 4+ ions in SrGdAlO 4 . The uniqueness of this solution is related to the pressure induced prolongation of the lifetime of the 2 E level of Mn 4+ ions resulting from a change in the covalency of the Mn 4+ –O 2− bond. Taking the advantage of this effect, the luminescence decay time was increased from 1.44 ms to 2.14 ms when the pressure was changed from ambient to 7.6 GPa. This allowed the development of a luminescent manometer with a maximum relative sensitivity of 7.85%/GPa at 3 GPa and sensitivities above S R > 5%/GPa in the pressure range of 1–7.6 GPa. Moreover, in the temperature range of 260–365 K, the lifetime value was independent of temperature changes, enabling a temperature invariant manometric factor of 134.
Dual generalized Bernstein basis Lewanowicz, Stanisław; Woźny, Paweł
Journal of approximation theory,
02/2006, Letnik:
138, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The generalized Bernstein basis in the space
Π
n
of polynomials of degree at most
n, being an extension of the
q-Bernstein basis introduced by Philips Bernstein polynomials based on the
q-integers, ...Ann. Numer. Math. 4 (1997) 511–518, is given by the formula S. Lewanowicz, P. Woźny, Generalized Bernstein polynomials, BIT Numer. Math. 44 (2004) 63–78,
B
i
n
(
x
;
ω
|
q
)
≔
1
(
ω
;
q
)
n
n
i
q
x
i
(
ω
x
-
1
;
q
)
i
(
x
;
q
)
n
-
i
(
i
=
0
,
1
,
…
,
n
)
.
We give explicitly the dual basis functions
D
k
n
(
x
;
a
,
b
,
ω
|
q
)
for the polynomials
B
i
n
(
x
;
ω
|
q
)
, in terms of big
q-Jacobi polynomials
P
k
(
x
;
a
,
b
,
ω
/
q
;
q
)
,
a and
b being parameters; the connection coefficients are evaluations of the
q-Hahn polynomials. An inverse formula—relating big
q-Jacobi, dual generalized Bernstein, and dual
q-Hahn polynomials—is also given. Further, an alternative formula is given, representing the dual polynomial
D
j
n
(
0
⩽
j
⩽
n
)
as a linear combination of
min
(
j
,
n
-
j
)
+
1
big
q-Jacobi polynomials with shifted parameters and argument. Finally, we give a recurrence relation satisfied by
D
k
n
, as well as an identity which may be seen as an analogue of the extended Marsden's identity R.N. Goldman, Dual polynomial bases, J. Approx. Theory 79 (1994) 311–346.
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