Lovelock gravity from entropic force

In this paper, we first generalize the formulation of entropic gravity to (n+1)-dimensional spacetime. Then, we propose an entropic origin for Gauss-Bonnet gravity and more general Lovelock gravity in arbitrary dimensions. As a result, we are able to derive Newton's law of gravitation as well as the corresponding Friedmann equations in these gravity theories. This procedure naturally leads to a derivation of the higher dimensional gravitational coupling constant of Friedmann/Einstein equation which is in complete agreement with the results obtained by comparing the weak field limit of Einstein equation with Poisson equation in higher dimensions. Our study shows that the approach presented here is powerful enough to derive the gravitational field equations in any gravity theory. PACS: 04.20.Cv, 04.50.-h, 04.70.Dy.Comment: 10 pages, new versio

Improving C4 photosynthesis to increase productivity under optimal and suboptimal conditions.

Although improving photosynthetic efficiency is widely recognized as an underutilized strategy to increase crop yields, research in this area is strongly biased towards species with C3 photosynthesis relative to C4 species. Here, we outline potential strategies for improving C4 photosynthesis to increase yields in crops by reviewing the major bottlenecks limiting the C4 NADP-malic enzyme pathway under optimal and suboptimal conditions. Recent experimental results demonstrate that steady-state C4 photosynthesis under non-stressed conditions can be enhanced by increasing Rubisco content or electron transport capacity, both of which may also stimulate CO2 assimilation at supraoptimal temperatures. Several additional putative bottlenecks for photosynthetic performance under drought, heat, or chilling stress or during photosynthetic induction await further experimental verification. Based on source-sink interactions in maize, sugarcane, and sorghum, alleviating these photosynthetic bottlenecks during establishment and growth of the harvestable parts are likely to improve yield. The expected benefits are also shown to be augmented by the increasing trend in planting density, which increases the impact of photosynthetic source limitation on crop yields

Dating the emergence of Influenza A (H5N1) Virus

Since the first detection of highly pathogenic avian influenza (H5N1) virus in geese in Guangdong, China, H5N1 viruses have transmitted to poultry throughout southern China. In late 2003 the first transmission wave spread the virus to multiple Southeast Asian countries. In May 2005, the second transmission wave of H5N1 virus westwards to Europe and Africa was initiated following a major outbreak in migratory birds at Qinghai Lake, China, while a third transmission wave has been initiated since mid-2005. Those viruses are now endemic in poultry populations in some affected regions and cause repeated outbreaks in poultry and increasing human infection cases, creating persistent pandemic concerns. Genetic data from systematic surveillance of H5N1 for the past seven years in marketing poultry, along with sequence data from outbreaks throughout the region, provide us with a unique opportunity to estimate the most recent common ancestor (MRCA) and postulate the dates of introduction of H5N1 variants into different affected countries. In this study, we estimated the time of emergence of those three transmission waves …postprin

Generic master equations for quasi-normal frequencies

Generic master equations governing the highly-damped quasi-normal frequencies [QNFs] of one-horizon, two-horizon, and even three-horizon spacetimes can be obtained through either semi-analytic or monodromy techniques. While many technical details differ, both between the semi-analytic and monodromy approaches, and quite often among various authors seeking to apply the monodromy technique, there is nevertheless widespread agreement regarding the the general form of the QNF master equations. Within this class of generic master equations we can establish some rather general results, relating the existence of "families" of QNFs of the form omega_{a,n} = (offset)_a + i n (gap) to the question of whether or not certain ratios of parameters are rational or irrational.Comment: 23 pages; V2: Minor additions, typos fixed. Matches published versio

A randomized comparison between three types of irrigating fluids during transurethral resection in benign prostatic hyperplasia

<p>Abstract</p> <p>Background</p> <p>Central nervous system changes, circulatory and electrolyte imbalances are the main complications of endoscopic transurethral resection of the prostate (TURP) which is known as transurethral resection (TUR) syndrome, which occurs as result of excessive absorption of irrigating fluid. We compare glycine 1.5% versus glucose 5% and normal saline 0.9% as irrigating solutions during TURP in patients with moderate to severe bladder outlet obstruction due to benign prostatic hyperplasia (BPH).</p> <p>Methods</p> <p>Three hundred sixty patients with symptomatic BPH were randomized into a prospective, controlled trial comparing the three irrigation modalities. One-hundred twenty patients used glycine 1.5% solution as irrigating fluid (glycine group), 120 patients used glucose 5% solution (glucose group) and 120 patients used normal saline 0.9% solution (saline group). Patient's demographics, operation time, hospital stay, postoperative amino acid glycine assay, postoperative serum cardiac troponin I and perioperative complications were noted.</p> <p>Results</p> <p>No difference was found between the groups in the immediate postoperative levels of hemoglobin and hematocrite. A high glycine level was associated with the TUR syndrome. Seventeen patients had TUR syndrome; all were in glycine group and they had the highest postoperative amino acid glycine levels. Slight increase in serum sodium (142.6 ± 12.6 mmol/l) was detected in saline group. Transient Hyperglycemia (170 ± 35.9 mg/dl) and hypokalemia (3.67 ± 0.92 mmol/l) occurred in the immediate postoperative period in the glucose group.</p> <p>Conclusion</p> <p>Endoscopic TURP performed using either glucose 5% or saline 0.9% irrigating solution during and after surgery is associated with lower incidence of TUR syndrome, lower catheterization period, shorter hospital stay and no cardiac toxicity in comparison with glycine 1.5% solution.</p> <p>Trial Registration</p> <p>This clinical trail had been approved and registered in PACT Registry; with identification number for the registry is ATMR2010010001793131.</p

Stability and aromaticity of nH2@B12N12 (n=1–12) clusters

Standard ab initio and density functional calculations are carried out to determine the structure, stability, and reactivity of B12N12 clusters with hydrogen doping. To lend additional support, conceptual DFT-based reactivity descriptors and the associated electronic structure principles are also used. Related cage aromaticity of this B12N12 and nH2@B12N12 are analyzed through the nucleus independent chemical shift values

Oocyte donor age has a significant impact on oocyte recipients' cumulative live-birth rate: a population-based cohort study

© 2019 Objective: To study the impact of the donor's and recipient's age on the cumulative live-birth rate (CLBR) in oocyte donation cycles. Design: A population-based retrospective cohort study. Setting: Not applicable. Patient(s): All women using donated oocytes (n = 1,490) in Victoria, Australia, between 2009 and 2015. Intervention(s): None. Main Outcome Measure(s): The association between the donor's and recipient's age and CLBR modeled by multivariate Cox proportional hazard regression with the covariates of male partner's age, recipient parity, and cause of infertility adjusted for, and donor age grouped as <30, 30–34, 35–37, 38–40, and ≥41 years, and recipient age as <35, 35–37, 38–40, 41–42, 43–44, and ≥45 years. Result(s): The mean age of the oocyte donors was 33.7 years (range: 21 to 45 years) with 49% aged 35 years and over. The mean age of the oocyte recipients was 41.4 years (range: 19 to 53 years) with 25.4% aged ≥45 years. There was a statistically significant relationship between the donor's age and the CLBR. The CLBR for recipients with donors aged <30 years and 30–34 years was 44.7% and 43.3%, respectively. This decreased to 33.6% in donors aged 35–37 years, 22.6% in donors aged 38–40 years, and 5.1% in donors aged ≥41 years. Compared with recipients with donors aged <30 years, the recipients with donors aged 38–40 years had 40% less chance of achieving a live birth (adjusted hazard ratio 0.60; 95% CI, 0.43–0.86) and recipients with donors aged ≥41 years had 86% less chance of achieving a live birth (adjusted hazard ratio 0.14; 95% CI, 0.04–0.44). The multivariate analysis showed no statistically significant effect of the recipient's age on CLBR. Conclusion(s): We have demonstrated that the age of the oocyte donor is critical to the CLBR and is independent of the recipient woman's age. Recipients using oocytes from donors aged ≥35 years had a statistically significantly lower CLBR when compared with recipients using oocytes from donors aged <35 years

IFNβ Protects Neurons from Damage in a Murine Model of HIV-1 Associated Brain Injury.

Infection with human immunodeficiency virus-1 (HIV-1) causes brain injury. Type I interferons (IFNα/β) are critical mediators of any anti-viral immune response and IFNβ has been implicated in the temporary control of lentiviral infection in the brain. Here we show that transgenic mice expressing HIV-1 envelope glycoprotein 120 in their central nervous system (HIVgp120tg) mount a transient IFNβ response and provide evidence that IFNβ confers neuronal protection against HIVgp120 toxicity. In cerebrocortical cell cultures, neuroprotection by IFNβ against gp120 toxicity is dependent on IFNα receptor 1 (IFNAR1) and the β-chemokine CCL4, as IFNAR1 deficiency and neutralizing antibodies against CCL4, respectively, abolish the neuroprotective effects. We find in vivo that IFNβ mRNA is significantly increased in HIVgp120tg brains at 1.5, but not 3 or 6 months of age. However, a four-week intranasal IFNβ treatment of HIVgp120tg mice starting at 3.5 months of age increases expression of CCL4 and concomitantly protects neuronal dendrites and pre-synaptic terminals in cortex and hippocampus from gp120-induced damage. Moreover, in vivo and in vitro data suggests astrocytes are a major source of IFNβ-induced CCL4. Altogether, our results suggest exogenous IFNβ as a neuroprotective factor that has potential to ameliorate in vivo HIVgp120-induced brain injury

In situ evidence for the structure of the magnetic null in a 3D reconnection event in the Earth's magnetotail

Magnetic reconnection is one of the most important processes in astrophysical, space and laboratory plasmas. Identifying the structure around the point at which the magnetic field lines break and subsequently reform, known as the magnetic null point, is crucial to improving our understanding reconnection. But owing to the inherently three-dimensional nature of this process, magnetic nulls are only detectable through measurements obtained simultaneously from at least four points in space. Using data collected by the four spacecraft of the Cluster constellation as they traversed a diffusion region in the Earth's magnetotail on 15 September, 2001, we report here the first in situ evidence for the structure of an isolated magnetic null. The results indicate that it has a positive-spiral structure whose spatial extent is of the same order as the local ion inertial length scale, suggesting that the Hall effect could play an important role in 3D reconnection dynamics.Comment: 14 pages, 4 figure