1,589 research outputs found
A Buffer Stocks Model for Stabilizing Price of Staple Food with Considering the Expectation of Non Speculative Wholesaler
This paper is a study of price stabilization in the
staple food distribution system. All stakeholders experience
market risks due to some possibility causes of price volatility.
Many models of price stabilization had been developed by
employing several approaches such as floor-ceiling prices,
buffer funds, export or import taxes, and subsidies. In the
previous researches, the models were expanded to increase the
purchasing price for producer and decrease the selling price
for consumer. Therefore, the policy can influence the losses for
non-speculative wholesaler that is reflected by the descending
of selling quantity and ascending of the stocks. The objective of
this model is not only to keep the expectation of both producer
and consumer, but also to protect non-speculative wholesaler
from the undesirable result of the stabilization policy. A
nonlinear programming model was addressed to determine the
instruments of intervention program. Moreover, the result
shows that the wholesaler behavior affects the intervention
costs.
Index Terms Buffer stocks, Price stabilization, Nonlinear
programming, Wholesaler behavior
Dynamic analysis of a lithium-boiling potassium refractory metal Rankine cycle power system for the Jet Propulsion Laboratory
Lithium-boiling potassium refractory metal Rankine cycle power system heat transfer model
Grantecan spectroscopic observations and confirmations of Planetary Nebulae candidates in the Northern Galactic Plane
We present Grantecan 10 m telescope (GTC) spectroscopic confirmations of 55
faint Planetary Nebulae (PNe) candidates discovered largely in the INT
Photometric H Survey of the Northern Galactic Plane (IPHAS) by our
pro-am collaboration. We confirm 46 of them as 'True' (T), 4 as 'Likely' (L)
and 5 as 'Possible' (P) PNe and including 5 new PNe central star (CSPN)
discoveries. This was from observations of 62 new candidates yielding a maximum
PN discovery success rate of 89%. The sensitivity and longer wavelength
coverage of IPHAS allows PNe to be found in regions of greater extinction and
at these lower Galactic latitudes, including PNe in a more advanced
evolutionary state and at larger distances compared to previously known
Galactic PNe. We use an holistic set of observed characteristics and optical
emission-line diagnostics to confirm candidates. Plasma properties have been
determined in a self-consistent way using PyNeb. This work is facilitated by
the functionality of our powerful, multi-wavelength database 'HASH' (Hong Kong,
Australian Astronomical Observatory, Strasbourg Observatory H-alpha Planetary
Nebula catalogue) that federates known imaging, spectroscopy and other
pertinent data for all Galactic T, L, P PNe and the significant numbers of
mimics. Reddenings, corrected radial velocities and PNe electron density and
temperature estimates are provided for these new PNe where possible.Comment: Accepted for publication by MNRA
First results of an Hα based search of classical Be stars in the Perseus Arm and beyond
We investigate a region of the Galactic plane, between 120° ≤ l ≤ 140° and-1° ≤ b≤+4°, and uncover a population of moderately reddened (E(B-V) ~ 1) classical Be stars within and beyond the Perseus and Outer Arms. 370 candidate emission-line stars (13≲r≲16) selected from the Isaac Newton Telescope Photometric Ha Survey of the Northern Galactic plane have been followed up spectroscopically. A subset of these, 67 stars with properties consistent with those of classical Be stars, have been observed at sufficient spectral resolution (δλ ≈ 2-4 Å) at blue wavelengths to narrow down their spectral types. We determine these to a precision estimated to be ±1 subtype and then we measure reddenings via spectral energy distribution fitting with reference to appropriate model atmospheres. Corrections for contribution to colour excess from circumstellar discs are made using an established scaling to Ha emission equivalent width. Spectroscopic parallaxes are obtained after luminosity class has been constrained via estimates of distances to neighbouring A/F stars with similar reddenings. Overwhelmingly, the stars in the sample are confirmed as luminous classical Be stars at heliocentric distances ranging from 2 kpc up to ~12 kpc. However, the errors are presently too large to enable the cumulative distribution function with respect to distance to distinguish between models placing the stars exclusively in spiral arms, or in a smooth exponentially declining distribution.Peer reviewe
Incomplete reversibility of estimated glomerular filtration rate decline following tenofovir disoproxil fumarate exposure.
BACKGROUND: Tenofovir disoproxil fumarate (TDF) has been linked to renal impairment, but the extent to which this impairment is reversible is unclear. We aimed to investigate the reversibility of renal decline during TDF therapy.
METHODS: Cox proportional hazards models assessed factors associated with discontinuing TDF in those with an exposure duration of >6 months. In those who discontinued TDF therapy, linear piecewise regression models estimated glomerular filtration rate (eGFR) slopes before initiation of, during, and after discontinuation of TDF therapy. Factors associated with not achieving eGFR recovery 6 months after discontinuing TDF were assessed using multivariable logistic regression.
RESULTS: We observed declines in the eGFR during TDF exposure (mean slopes, -15.7 mL/minute/1.73 m(2)/year [95% confidence interval {CI}, -20.5 to -10.9] during the first 3 months and -3.1 mL/minute/1.73 m(2)/year [95% CI, -4.6 to -1.7] thereafter) and evidence of eGFR increases following discontinuation of TDF therapy (mean slopes, 12.5 mL/minute/1.73 m(2)/year [95% CI, 8.9-16.1] during the first 3 months and 0.8 mL/minute/1.73 m(2)/year [95% CI,.1-1.5] thereafter). Following TDF discontinuation, 38.6% of patients with a decline in the eGFR did not experience recovery. A higher eGFR at baseline, a lower eGFR after discontinuation of TDF therapy, and more-prolonged exposure to TDF were associated with an increased risk of incomplete recovery 6 months after discontinuation of TDF therapy.
CONCLUSIONS: This study shows that a decline in the eGFR during TDF therapy was not fully reversible in one third of patients and suggests that prolonged TDF exposure at a low eGFR should be avoided
Dicer-2 Processes Diverse Viral RNA Species
RNA silencing pathways play critical roles in gene regulation, virus infection, and transposon control. RNA interference (RNAi) is mediated by small interfering RNAs (siRNAs), which are liberated from double-stranded (ds)RNA precursors by Dicer and guide the RNA-induced silencing complex (RISC) to targets. Although principles governing small RNA sorting into RISC have been uncovered, the spectrum of RNA species that can be targeted by Dicer proteins, particularly the viral RNAs present during an infection, are poorly understood. Dicer-2 potently restricts viral infection in insects by generating virus-derived siRNAs from viral RNA. To better characterize the substrates of Dicer-2, we examined the virus-derived siRNAs produced during the Drosophila antiviral RNAi response to four different viruses using high-throughput sequencing. We found that each virus was uniquely targeted by the RNAi pathway; dicing substrates included dsRNA replication intermediates and intramolecular RNA stem loops. For instance, a putative intergenic RNA hairpin encoded by Rift Valley Fever virus generates abundant small RNAs in both Drosophila and mosquito cells, while repetitive sequences within the genomic termini of Vaccinia virus, which give rise to abundant small RNAs in Drosophila, were found to be transcribed in both insect and mammalian cells. Moreover, we provide evidence that the RNA species targeted by Dicer-2 can be modulated by the presence of a viral suppressor of RNAi. This study uncovered several novel, heavily targeted features within viral genomes, offering insight into viral replication, viral immune evasion strategies, and the mechanism of antiviral RNAi. © 2013 Sabin et al
Ethnic inequalities in mental health and socioeconomic status among older women living with HIV: results from the PRIME Study.
OBJECTIVES: Women living with HIV in the UK are an ethnically diverse group with significant psychosocial challenges. Increasing numbers are reaching older age. We describe psychological and socioeconomic factors among women with HIV in England aged 45-60 and explore associations with ethnicity. METHODS: Analysis of cross-sectional data on 724 women recruited to the PRIME Study. Psychological symptoms were measured using the Patient Health Questionnaire 4 and social isolation with a modified Duke-UNC Functional Social Support Scale. RESULTS: Black African (BA) women were more likely than Black Caribbean or White British (WB) women to have a university education (48.3%, 27.0%, 25.7%, respectively, p<0.001), but were not more likely to be employed (68.4%, 61.4%, 65.2%, p=0.56) and were less likely to have enough money to meet their basic needs (56.4%, 63.0%, 82.9%, p<0.001). BA women were less likely to report being diagnosed with depression than WB women (adjusted odds ratio (aOR) 0.40, p<0.001) but more likely to report current psychological distress (aOR 3.34, p<0.05). CONCLUSIONS: We report high levels of poverty, psychological distress and social isolation in this ethnically diverse group of midlife women with HIV, especially among those who were BA. Despite being more likely to experience psychological distress, BA women were less likely to have been diagnosed with depression suggesting a possible inequity in access to mental health services. Holistic HIV care requires awareness of the psychosocial needs of older women living with HIV, which may be more pronounced in racially minoritised communities, and prompt referral for support including psychology, peer support and advice about benefits
Epidemics with multistrain interactions: The interplay between cross immunity and antibody-dependent enhancement
This paper examines the interplay of the effect of cross immunity and antibody-dependent enhancement (ADE) in multistrain diseases. Motivated by dengue fever, we study a model for the spreading of epidemics in a population with multistrain interactions mediated by both partial temporary cross immunity and ADE. Although ADE models have previously been observed to cause chaotic outbreaks, we show analytically that weak cross immunity has a stabilizing effect on the system. That is, the onset of disease fluctuations requires a larger value of ADE with small cross immunity than without. However, strong cross immunity is shown numerically to cause oscillations and chaotic outbreaks even for low values of ADE. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3270261
Improved kidney function in patients who switch their protease inhibitor from atazanavir or lopinavir to darunavir
OBJECTIVE: Atazanavir (ATV) and lopinavir (LPV) have been associated with kidney
disease progression in HIV positive patients, with no data reported for darunavir (DRV).
We examined kidney function in patients who switched their protease inhibitor from
ATV or LPV to DRV.
DESIGN: Cohort study.
METHODS: Data were from the UK CHIC study. We compared pre and post switch
estimated glomerular filtration rate (eGFR) slopes (expressed in ml/min per 1.73 m2 per
year) in all switchers and those with rapid eGFR decline (>5 ml/min per 1.73 m2 per
year) on ATV or LPV. Mixed-effects models were adjusted for age, gender, ethnicity,
eGFR at switch and time updated CD4þ cell count, HIV RNA and cumulative tenofovir
(tenofovir disoproxil fumarate) exposure.
RESULTS: Data from 1430 patients were included. At the time of switching to DRV,
median age was 45 years, 79% were men, 76% had an undetectable viral load, and
median eGFR was 93 ml/min per 1.73 m2
. Adjusted mean (95% confidence interval) pre
and post switch eGFR slopes were 0.84 (1.31, 0.36) and 1.23 (0.80, 1.66) for ATV
(P < 0.001), and 0.57 (1.09, 0.05) and 0.62 (0.28, 0.96) for LPV (P < 0.001). Stable
or improved renal function was observed in patients with rapid eGFR decline on ATV or
LPV who switched to DRV [15.27 (19.35, 11.19) and 3.72 (1.78, 5.66), P < 0.001
for ATV, 11.93 (14.60, 9.26) and 0.87 (0.54, 2.27), P < 0.001 for LPV]. Similar
results were obtained if participants who discontinued tenofovir disoproxil fumarate at
the time of switch were excluded.
CONCLUSIONS: We report improved kidney function in patients who switched from ATV
or LPV to DRV, suggesting that DRV may have a more favourable renal safety profile
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