143 research outputs found
MODIFICATION OF TURC METHOD TO DETERMINE THE WATER YIELDS OF SUB-BASINS IN THRACE REGION OF TURKEY
In this research, directly measured flow values in three different basins in Thrace region, that is located in the Northwest Part of Turkey, were compared to the computed ones applying the Turc method to these basins. It is concluded that Turc method with original coefficients, 300 and 0.9, could not be used because of huge
discrepancies between the measured and calculated values. Instead, coefficients of 601 and 0.65, respectively, were used after the correction using long term measured flow rates. Employing the modified Turc method for these research basins, reservoirs volume are reduced by 50.7 %. This may decrease the total cost of the
reservoirs by about 20-30 % through reducing occupied surface area, embankment and crest height
DETERMINATION OF THE WATER YIELDS FOR SMALL BASINS IN SEMI-ARID AREAS: APPLICATION OF THE MODIFIED TURC METHOD TO THE TURKEY’S CONDITIONS
The Turc Method is used widely in Turkey to determine runoff depths therefore, water yield from a particular watershed and subsequently the reservoir’s volume by Turkish General Directorate of Rural Services which is responsible for the investments on agricultural and rural infrastructures. However the method over predicts the water yield markedly when compared to the directly measured long-term water yields, which increases the total cost for the instruction of
reservoirs and leads to environmental hazards due to disturbing more agricultural areas. In this research, the Turc Method was modifi ed through replacing the new coeffi cients with the original coeffi cients of the 300 and 0.9 by fi tting the calculated values to the directly measured long-term, a total of 223 years, in 22 sub-basin distributed throughout Turkey. Coeffi cients 566 and 0.68 were proposed as average values for Turkey in general instead 300 and
0.9, respectively, though the new coeffi cients for a particular watershed varied widely from 20 to 1135 and from 0.4 to 1.32, respectively. The country’s sub-basins divided into three groups in terms of basin characteristics affective on these coeffi cients and new coeffi cients were also suggested for each group. Employing the modifi ed Turc Method with these new coeffi cients for the research sub-basins can reduce the reservoir’s volume by 45 % and this may decrease the total cost of the reservoirs by about 20-25 % through reducing occupied surface area, embankment and crest height
Observations of Temporal Group Delays in Slow-Light Multiple Coupled Photonic Crystal Cavities
We demonstrate temporal group delays in coherently coupled high- Q multicavity photonic crystals, in an all-optical analog to electromagnetically induced transparency. We report deterministic control of the group delay up to 4x the single cavity lifetime in our room-temperature chip. Supported by three-dimensional numerical simulations and theoretical analyses, our multipump beam approach enables control of the multicavity resonances and intercavity phase, in both single and double transparency peaks. The standing-wave wavelength-scale photon localization allows direct scalability for chip-scale optical pulse trapping and coupled-cavity quantum electrodynamics
Deterministic integrated tuning of multi-cavity resonances and phase for slow-light in coupled photonic crystal cavities
We present the integrated chip-scale tuning of multiple photonic crystal
cavities. The optimized implementation allows effective and precise tuning of
multiple cavity resonances (up to ~1.60 nm/mW) and inter-cavity phase (~ 0.038
pi/mW) by direct local temperature tuning on silicon nanomembranes. Through
designing the serpentine metal electrodes and careful electron-beam alignment
to avoid cavity mode overlap, the coupled photonic crystal L3 cavities preserve
their high quality factors. The deterministic resonance and phase control
enables switching between the all-optical analogue of
electromagnetically-induced-transparency (EIT) to flat-top filter lineshapes,
with future applications of trapping photons/photonic transistors and
optoelectronic modulators
Evaluating the performance of SURFEXv5 as a new land surface scheme for the ALADINcy36 and ALARO-0 models
The newly developed land surface scheme SURFEX (SURFace EXternalisee) is implemented into a limited-area numerical weather prediction model running operationally in a number of countries of the ALADIN and HIRLAM consortia. The primary question addressed is the ability of SURFEX to be used as a new land surface scheme and thus assessing its potential use in an operational configuration instead of the original ISBA (Interactions between Soil, Biosphere, and Atmosphere) scheme. The results show that the introduction of SURFEX either shows improvement for or has a neutral impact on the 2m temperature, 2m relative humidity and 10m wind. However, it seems that SURFEX has a tendency to produce higher maximum temperatures at high-elevation stations during winter daytime, which degrades the 2m temperature scores. In addition, surface radiative and energy fluxes improve compared to observations from the Cabauw tower. The results also show that promising improvements with a demonstrated positive impact on the forecast performance are achieved by introducing the town energy balance (TEB) scheme. It was found that the use of SURFEX has a neutral impact on the precipitation scores. However, the implementation of TEB within SURFEX for a high-resolution run tends to cause rainfall to be locally concentrated, and the total accumulated precipitation obviously decreases during the summer. One of the novel features developed in SURFEX is the availability of a more advanced surface data assimilation using the extended Kalman filter. The results over Belgium show that the forecast scores are similar between the extended Kalman filter and the classical optimal interpolation scheme. Finally, concerning the vertical scores, the introduction of SURFEX either shows improvement for or has a neutral impact in the free atmosphere
Observations of zero-order bandgaps in negative-index photonic crystal superlattices at the near-infrared
We present the first observations of zero-n bandgaps in photonic crystal
superlattices consisting of alternating stacks of negative index photonic
crystals and positive index dielectric materials in the near-infrared. Guided
by ab initio three-dimensional numerical simulations, the fabricated
nanostructured superlattices demonstrate the presence of zero-order gaps in
remarkable agreement with theoretical predictions across a range of different
superlattice periods and unit cell variations. These volume-averaged zero-index
superlattice structures present a new type of photonic band gap, with potential
for complete wavefront control for arbitrary phase delay lines and open cavity
resonances.Comment: 14 pages, 3 Figure
Prognostic value of fractional flow reserve: Linking physiologic severity to clinical outcomes
BACKGROUND: Fractional flow reserve (FFR) has become an established tool for guiding treatment, but its graded relationship to clinical outcomes as modulated by medical therapy versus revascularization remains unclear.OBJECTIVES: The study hypothesized that FFR displays a continuous relationship between its numeric value and prognosis, such that lower FFR values confer a higher risk and therefore receive larger absolute benefits from revascularization.METHODS: Meta-analysis of study- and patient-level data investigated prognosis after FFR measurement. An interaction term between FFR and revascularization status allowed for an outcomes-based threshold.RESULTS: A total of 9,173 (study-level) and 6,961 (patient-level) lesions were included with a median follow-up of 16 and 14 months, respectively. Clinical events increased as FFR decreased, and revascularization showed larger net benefit for lower baseline FFR values. Outcomes-derived FFR thresholds generally occurred around the range 0.75 to 0.80, although limited due to confounding by indication. FFR measured immediately after stenting also showed an inverse relationship with prognosis (hazard ratio: 0.86, 95% confidence interval: 0.80 to 0.93; p < 0.001). An FFR-assisted strategy led to revascularization roughly half as often as an anatomy-based strategy, but with 20% fewer adverse events and 10% better angina relief.CONCLUSIONS: FFR demonstrates a continuous and independent relationship with subsequent outcomes, modulated by medical therapy versus revascularization. Lesions with lower FFR values receive larger absolute benefits from revascularization. Measurement of FFR immediately after stenting also shows an inverse gradient of risk, likely from residual diffuse disease. An FFR-guided revascularization strategy significantly reduces events and increases freedom from angina with fewer procedures than an anatomy-based strategy
Concurrent validity of self-rating scale of self-directed learning and self-directed learning instrument among Italian nursing students
BACKGROUND: Self-Directed Learning develops when students take the initiative for their learning, recognising needs, formulating goals, identifying resources, implementing appropriate strategies and evaluating learning outcomes. This should be seen as a collaborative process between the nurse educator and the learner. At the international level, various instruments have been used to measure Self-Directed Learning abilities (SDL), both in original and in culturally-adapted versions. However, few instruments have been subjected to full validation, and no gold standard reference has been established to date. In addition, few researchers have adopted the established tools to assess the concurrent validity of the emerging new tools. Therefore, the aim of this study was to measure the concurrent validity between the Self-Rating Scale of Self-Directed Learning (SRSSDL_Ita) - Italian version and the Self-Directed Learning Instruments (SDLI) in undergraduate nursing students.
METHODS: A concurrent validity study design was conducted in a Bachelor level nursing degree programme located in Italy. All nursing students attending the first, second or third year (n=428) were the target sample. The SRSSDL_Ita, and the SDLI were used. The Pearson correlation was used to determine the concurrent validity between the instruments; the confidence of intervals (CI 95%) bias-corrected and accelerated bootstrap (BCa), were also calculated.
RESULTS: The majority of participants were students attending their first year (47.9%), and were predominately female (78.5%). Their average age was 22.5\ub14.1. The SDL abilities scores, as measured with the SRSSDL_Ita (min 40, max 200), were, on average, 160.79 (95% CI 159.10-162.57; median 160); while with the SDLI (min 20, max 100), they were on average 82.57 (95% CI 81.79-83.38; median 83). The Pearson correlation between the SRSSDL_Ita and SDLI instruments was 0.815 (CI BCa 95% 0.774-0.848), (p=0.000).
CONCLUSIONS: The findings confirm the concurrent validity of the SRSSDL_Ita with the SDLI. The SRSSDL_Ita instrument can be useful in the process of identifying Self-Directed Learning abilities, which are essential for students to achieve the expected learning goals and become lifelong learners
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