Maximal acceleration or maximal accelerations?

We review the arguments supporting the existence of a maximal acceleration for a massive particle and show that different values of this upper limit can be predicted in different physical situations.Comment: 13 pages, Latex, to be published in Int. J. Mod. Phys.

Effects of morinda citrifolia (noni) and diet complexity on growth performance in weanling pigs

Two experiments were conducted to determine the effects of concentration (0, 0.75, 1.5, 3.0, and 6.0%) of Morinda citrifolia (no-ni; Morinda Agricultural Products, Orem, UT) and diet complexity in weanling pigs. In Exp. 1, 210 pigs (initially 13.4 lb) were used in a 35-d growth assay; there were 7 pigs per pen and 6 pens per treatment. Diets were corn-soybean meal-based, and lysine concentrations were 1.8% for d 0 to 7, 1.6% for d 7 to 21, and 1.4% for d 21 to 35 with feed and water con-sumed on an ad libitum basis. Increasing the concentration of noni in the diet from 0 to 3% had no effects on pellet durability index (PDI) for the d 0 to 7 and 7 to 21 diets. Average daily gain (quadratic effect, P < 0.03) and F/G (quadratic effect, P < 0.10) for d 0 to 7 and F/G for d 0 to 21 (quadratic effect, P < 0.04) improved as noni concentration in the diet was increased from 0 to 0.75%. However, no treatment effects were observed overall (d 0 to 35). For Exp. 2, 168 pigs (initially 13.9 lb) were used in a 35-d growth assay; there were 6 pigs per pen and 7 pens per treatment. Treatments were arranged as a 2 × 2 factorial with main effects of diet formulation (simple vs. complex) and noni addition (0 vs. 3%). Simple diets had the same minimum nutrient specifications as complex diets but had no added lactose or spray-dried animal plasma for d 0 to 7 and only 10% added whey for d 7 to 21. Pelleting data indicated improved PDI with no additional energy inputs when noni was added to the simple diets (for d 21 to 35). Pigs fed simple diets had lower ADG (P < 0.06) for d 0 to 7 and lower ADG and ADFI (P < 0.06) for d 0 to 21 than pigs fed complex diets. During d 0 to 35 for ADG and d 0 to 21 for F/G, addition of noni to the simple diets had negative effects (diet complexity × noni interaction, P < 0.02). In conclusion, adding 0.75 to 3% noni to complex diets improved growth performance early in a titration experiment but had negative effects when added to the simple diet formulations used in a second experiment

Effects of adding saturated fat to diets with sorghum-based dried distillers grains with solubles on growth performance and carcass characteristics in finishing pigs

Two experiments were conducted to determine the effects of adding sources of saturated fat to diets with sorghum-based dried distillers grains with solubles (DDGS). For Exp. 1, 112 barrows (initially 140 lb) were used in a 69-d growth assay with 7 pigs per pen and 4 pens per treatment. Treatments were a corn-soybean meal-based control and diets having 40% sorghum-based DDGS (U.S. En-ergy Partners, Russell, KS) without and with 5% added tallow or palm oil. Feed and water were consumed on an ad libitum basis until pigs were slaughtered (average BW 283 lb) to allow collection of carcass data and jowl samples. Fatty acid composition of jowl samples was used to calculate iodine value (IV) as an indicator of carcass fat firmness. Overall (d 0 to 69), the corn-soybean control supported greater ADG and ADFI (P 0.9) compared with the DDGS treatments. Adding 5% beef tallow and palm oil to diets with DDGS improved overall F/G (P 0.14). Changes in IV indicated softer fat in pigs fed DDGS (P 0.14) compared with DDGS treatments. Adding fat sources to diets with DDGS tended to improve (P < 0.06) overall F/G, and coconut oil improved F/G compared with stearic acid (P < 0.001). Pigs fed the control diet had greater (P < 0.05) HCW than pigs fed the DDGS treatments. Pigs fed the control diet had lower IV and greater firmness score than pigs fed diets with added DDGS (P < 0.02). Adding fat sources to diets with DDGS improved these estimates of carcass firmness and tip to tip distance for suspended bellies (P < 0.001); coconut oil had a much greater effect than stearic acid (P < 0.001). In conclusion, adding beef tallow, palm oil, and coconut oil to diets with 40% DDGS improved efficiency of gain in finishing pigs. However, only coconut oil restored carcass firmness to levels at or above a corn-soybean diet without DDGS

Double down on remote sensing for biodiversity estimation. A biological mindset

In the light of unprecedented planetary changes in biodiversity, real-time and accurate ecosystem and biodiversity assessments are becoming increasingly essential for informing policy and sustainable development. Biodiversity monitoring is a challenge, especially for large areas such as entire continents. Nowadays, spaceborne and airborne sensors provide information that incorporate wavelengths that cannot be seen nor imagined with the human eye. This is also now accomplished at unprecedented spatial resolutions, defined by the pixel size of images, achieving less than a meter for some satellite images and just millimeters for airborne imagery. Thanks to different modeling techniques, it is now possible to study functional diversity changes over different spatial and temporal scales. At the heart of this unifying framework are the “spectral species”—sets of pixels with a similar spectral signal—and their variability over space. The aim of this paper is to summarize the power of remote sensing for directly estimating plant species diversity, particularly focusing on the spectral species concept

Towards an understanding of the evolution of the scaling relations for supermassive black holes

The growth of the supermassive black holes (BHs) that reside at the centres of most galaxies is intertwined with the physical processes that drive the formation of the galaxies themselves. The evolution of the relations between the mass of the BH, m_BH, and the properties of its host therefore represent crucial aspects of the galaxy formation process. We use a cosmological simulation, as well as an analytical model, to investigate how and why the scaling relations for BHs evolve with cosmic time. We find that a simulation that reproduces the observed redshift zero relations between m_BH and the properties of its host galaxy, as well as the thermodynamic profiles of the intragroup medium, also reproduces the observed evolution in the ratio m_BH/m_s for massive galaxies, although the evolution of the m_BH/sigma relation is in apparent conflict with observations. The simulation predicts that the relations between m_BH and the binding energies of both the galaxy and its dark matter halo do not evolve, while the ratio m_BH/m_halo increases with redshift. The simple, analytic model of Booth & Schaye (2010), in which the mass of the BH is controlled by the gravitational binding energy of its host halo, quantitatively reproduces the latter two results. Finally, we can explain the evolution in the relations between m_BH and the mass and binding energy of the stellar component of its host galaxy for massive galaxies (m_s~10^11 M_sun) at low redshift (z<1) if these galaxies grow primarily through dry mergers.Comment: 8 pages, 3 figures; MNRAS accepte

The Effectiveness of Cyrene as a Solvent in Exfoliating 2D TMDs Nanosheets

The pursuit of environmentally friendly solvents has become an essential research topic in sustainable chemistry and nanomaterial science. With the need to substitute toxic solvents in nanofabrication processes becoming more pressing, the search for alternative solvents has taken on a crucial role in this field. Additionally, the use of toxic, non-economical organic solvents, such as N-methyl-2 pyrrolidone and dimethylformamide, is not suitable for all biomedical applications, even though these solvents are often considered as the best exfoliating agents for nanomaterial fabrication. In this context, the success of producing two-dimensional transition metal dichalcogenides (2D TMDs), such as MoS2 and WS2, with excellent captivating properties is due to the ease of synthesis based on environment-friendly, benign methods with fewer toxic chemicals involved. Herein, we report for the first time on the use of cyrene as an exfoliating agent to fabricate monolayer and few-layered 2D TMDs with a versatile, less time-consuming liquid-phase exfoliation technique. This bio-derived, aprotic, green and eco-friendly solvent produced a stable, surfactant-free, concentrated 2D TMD dispersion with very interesting features, as characterized by UV–visible and Raman spectroscopies. The surface charge and morphology of the fabricated nanoflakes were analyzed using ς-potential and scanning electron microscopy. The study demonstrates that cyrene is a promising green solvent for the exfoliation of 2D TMD nanosheets with potential advantages over traditional organic solvents. The ability to produce smaller-sized—especially in the case of WS2 as compared to MoS2—and mono/few-layered nanostructures with higher negative surface charge values makes cyrene a promising candidate for various biomedical and electronic applications. Overall, the study contributes to the development of sustainable and environmentally friendly methods for the production of 2D nanomaterials for various applications

Finite Black Hole Entropy and String Theory

An accelerating observer sees a thermal bath of radiation at the Hawking temperature which is proportional to the acceleration. Also, in string theory there is a Hagedorn temperature beyond which one cannot go without an infinite amount of energy. Several authors have shown that in the context of Hawking radiation a limiting temperature for string theory leads to a limiting acceleration, which for a black hole implies a minimum distance from the horizon for an observer to remain stationary. We argue that this effectively introduces a cutoff in Rindler space or the Schwarzschild geometry inside of which accelerations would exceed this maximum value. Furthermore, this natural cutoff in turn allows one to define a finite entropy for Rindler space or a black hole as all divergences were occurring on the horizon. In all cases if a particular relationship exists between Newton's constant and the string tension then the entropy of the string modes agrees with the Bekenstein-Hawking formula.Comment: 17 pages, 1 figure, Florida Preprint UFIFT-HEP-94-0

The Proton-Boron Reaction Increases the Radiobiological Effectiveness of Clinical Low- and High-Energy Proton Beams: Novel Experimental Evidence and Perspectives

Protontherapy is a rapidly expanding radiotherapy modality where accelerated proton beams are used to precisely deliver the dose to the tumor target but is generally considered ineffective against radioresistant tumors. Proton-Boron Capture Therapy (PBCT) is a novel approach aimed at enhancing proton biological effectiveness. PBCT exploits a nuclear fusion reaction between low-energy protons and 11B atoms, i.e. p+11B→ 3α (p-B), which is supposed to produce highly-DNA damaging α-particles exclusively across the tumor-conformed Spread-Out Bragg Peak (SOBP), without harming healthy tissues in the beam entrance channel. To confirm previous work on PBCT, here we report new in-vitro data obtained at the 62-MeV ocular melanoma-dedicated proton beamline of the INFN-Laboratori Nazionali del Sud (LNS), Catania, Italy. For the first time, we also tested PBCT at the 250-MeV proton beamline used for deep-seated cancers at the Centro Nazionale di Adroterapia Oncologica (CNAO), Pavia, Italy. We used Sodium Mercaptododecaborate (BSH) as 11B carrier, DU145 prostate cancer cells to assess cell killing and non-cancer epithelial breast MCF-10A cells for quantifying chromosome aberrations (CAs) by FISH painting and DNA repair pathway protein expression by western blotting. Cells were exposed at various depths along the two clinical SOBPs. Compared to exposure in the absence of boron, proton irradiation in the presence of BSH significantly reduced DU145 clonogenic survival and increased both frequency and complexity of CAs in MCF-10A cells at the mid- and distal SOBP positions, but not at the beam entrance. BSH-mediated enhancement of DNA damage response was also found at mid-SOBP. These results corroborate PBCT as a strategy to render protontherapy amenable towards radiotherapy-resilient tumor. If coupled with emerging proton FLASH radiotherapy modalities, PBCT could thus widen the protontherapy therapeutic index

Quantum physics in inertial and gravitational fields

Covariant generalizations of well-known wave equations predict the existence of inertial-gravitational effects for a variety of quantum systems that range from Bose-Einstein condensates to particles in accelerators. Additional effects arise in models that incorporate Born reciprocity principle and the notion of a maximal acceleration. Some specific examples are discussed in detail.Comment: 25 pages,1 figure,to appear in "Relativity in Rotating Frame