Atom gravimeters and gravitational redshift

In a recent paper, H. Mueller, A. Peters and S. Chu [A precision measurement of the gravitational redshift by the interference of matter waves, Nature 463, 926-929 (2010)] argued that atom interferometry experiments published a decade ago did in fact measure the gravitational redshift on the quantum clock operating at the very high Compton frequency associated with the rest mass of the Caesium atom. In the present Communication we show that this interpretation is incorrect.Comment: 2 pages, Brief Communication appeared in Nature (2 September 2010

Solving Tree Problems with Category Theory

Artificial Intelligence (AI) has long pursued models, theories, and techniques to imbue machines with human-like general intelligence. Yet even the currently predominant data-driven approaches in AI seem to be lacking humans' unique ability to solve wide ranges of problems. This situation begs the question of the existence of principles that underlie general problem-solving capabilities. We approach this question through the mathematical formulation of analogies across different problems and solutions. We focus in particular on problems that could be represented as tree-like structures. Most importantly, we adopt a category-theoretic approach in formalising tree problems as categories, and in proving the existence of equivalences across apparently unrelated problem domains. We prove the existence of a functor between the category of tree problems and the category of solutions. We also provide a weaker version of the functor by quantifying equivalences of problem categories using a metric on tree problems.Comment: 10 pages, 4 figures, International Conference on Artificial General Intelligence (AGI) 201

Reply to: Atom gravimeters and the gravitational redshift

We stand by our result [H. Mueller et al., Nature 463, 926-929 (2010)]. The comment [P. Wolf et al., Nature 467, E1 (2010)] revisits an interesting issue that has been known for decades, the relationship between test of the universality of free fall and redshift experiments. However, it arrives at its conclusions by applying the laws of physics that are questioned by redshift experiments; this precludes the existence of measurable signals. Since this issue applies to all classical redshift tests as well as atom interferometry redshift tests, these experiments are equivalent in all aspects in question.Comment: Reply to P. Wolf et al., arXiv:1009.060

Gravitational redshift of galaxies in clusters as predicted by general relativity

The theoretical framework of cosmology is mainly defined by gravity, of which general relativity is the current model. Recent tests of general relativity within the \Lambda Cold Dark Matter (CDM) model have found a concordance between predictions and the observations of the growth rate and clustering of the cosmic web. General relativity has not hitherto been tested on cosmological scales independent of the assumptions of the \Lambda CDM model. Here we report observation of the gravitational redshift of light coming from galaxies in clusters at the 99 per cent confidence level, based upon archival data. The measurement agrees with the predictions of general relativity and its modification created to explain cosmic acceleration without the need for dark energy (f(R) theory), but is inconsistent with alternative models designed to avoid the presence of dark matter.Comment: Published in Nature issued on 29 September 2011. This version includes the Letter published there as well as the Supplementary Information. 23 pages, 7 figure

Technical Review of Fin Addition Analysis of Air Intake Valve on Gas-Oil Fuel Engine

Modification of single-fuel diesel engine into dual-fuel diesel engine has been done by researchers to solve the problem of depletion petroleum reserves. Even the problem petroleum reserves are projected to be exhausted in the next 50 years. Gas-Oil fuel engine focus on solar-CNG as a fuel. Explanation of the difference in the fuel ratio of diesel engines with Gas-Oil fuel diesel engines has considerable differences. The factors that are discussed here are the factors of mixing air and fuel. The amount of fuel in the Gas-Oil fuel diesel engine causes an increase in the gas fuel mass flow rate (CNG), although with the addition of fuel gas, the mass flow rate of diesel oil is reduced. In this paper, the Gas-Oil fuel engines research and development fueled using solar-CNG are highlighted to keep the performance of the engine. Modification focused on air intake valve to give maximum turbulent flow ratio and effect on increasing Gas-Oil fuel engine performance. The high activities for future Gas-Oil fuel engines  research and development to meet future Gas-Oil fuel engine solar-CNG is recorded in the paper

Analisa Pengaruh Penambahan Fin Pada Air Intake Valve Gas – Oil Fuel Engine Terhadap Performa Mesin Berdasarkan Eksperimen

Modifikasi mesin diesel berbahan bakar tunggal menjadi mesin diesel berbahan bakar ganda atau Gas - Oil Fuel Engine banyak dilakukan oleh peneliti untuk menyelesaikan permasalahan semakin menipisnya cadangan minyak bumi di dunia. Bahkan cadangan minyak bumi yang semakin lama semakin berkurang sudah diproyeksikan akan habis 50 tahun ke depan. Sistem kerja dari Gas - Oil Fuel Engine adalah memasukkan BBG (Bahan Bakar Gas) ke dalam ruang bakar bersamaan dengan udara pada saat langkah hisap di intake manifold dan akan ikut terbakar dengan solar sebagai pemantiknya. BBG yang digunakan adalah CNG (Compressed Natural Gas). Namun kinerja mesin ketika menggunakan penambahan bahan bakar gas mengalami penurunan. Modifikasi penambahan fixed fin pada air intake valve dilakukan untuk menaikkan swirl ratio sehingga turbulansi udara masuk bersamaan dengan bahan bakar gas menjadi lebih baik. Akibatnya pembakaran yang terjadi akan semakin baik. Dengan menggunakan penambahan fixed fin pada air intake valve gas-oil fuel engine, dapat menaikkan kinerja atau performa mesin menjadi lebih baik. Daya yang dihasilkan oleh mesin meningkat hingga pada beban maksimum dengan penambahan fixed fin. Sedangkan torsi meningkat dengan penambahan fixed fin pada keadaan beban maksimum. Untuk specific energy consumption (SEC) atau konsumsi energi spesifik menjadi akibat dari penambahan fixed fin. =================================================================================================== Modification of single-fuel diesel engine into dual-fuel diesel engine or specifically Gas - Oil Fuel Engine have been done by researchers to solve the problem of depletion petroleum reserves in the world. Petroleum reserves are projected to be exhausted in the next 50 years or less by prediction. The working system of the Gas - Oil Fuel Engine is inject (Fuel Gas) into the combustion chamber along with the air during the suction step in the intake manifold and will burn with the diesel as the lighter. Fuel Gas used here is CNG (Compressed Natural Gas). But the performance of engine when using the addition of fuel gas has decreased. The modification like the addition of fixed fin in the air intake valve is done to increase the swirl ratio. So that turbulent flow of air comes in along with the gas fuel to be better. As a result, combustion process in combustion chamber will be better. By applying a fixed fin addition into the air intake valve gas-oil fuel engine, it can boost engine performance more better. The power generated by the engine with fin additing increases at maximum load. While torque of engine with fin additing increased in maximum load condition. For specific energy consumption (SEC) has been decreased impact of fin additing on air intake valve

A new perspective of the climatological features of upper-level cut-off lows in the Southern Hemisphere

This study presents a detailed view of the seasonal variability of upper-level cut-off lows (COLs) in the Southern Hemisphere. The COLs are identified and tracked using data from a 36-year period of the European Centre for Medium Range Weather Forecast reanalysis (ERA-Interim). The objective identification of the COLs uses a new approach, which is based on 300 hPa relative vorticity minima, and three restrictive criteria of the presence of a cold-core, stratospheric potential vorticity intrusion, and cut-off cyclonic circulation. The highest COL activity is in agreement with previous studies, located near three main continental areas (Australia, South America, and Africa), with maximum frequencies usually observed in the austral autumn. The COL mean intensity values show a marked seasonal and spatial variation, with maximum (minimum) values during the austral winter (summer), a unique feature that has not been observed previously in studies based on the geopotential. The link between intensity and lysis is examined, and finds that weaker systems are more susceptible to lysis in the vicinity of the Andes Cordillera, associated with the topographic Rossby wave. Lysis and genesis regions are close to each other, confirming that COLs are quasi-stationary systems. Also, COLs tend to move eastward and are faster over the higher latitudes. The mean growth/decay rates coincide with the major genesis and lysis density regions, such as the significant decay values across the Andes all year. As a consequence of using vorticity for the tracking method a longer lifetime of COLs is detected than in other studies, but this does not affect the total frequency of occurrence. Comparisons with other studies suggest that the differences in seasonality are due to uncertainties in the reanalyses and the methods used to identify COLs

Topical Hpmc/s-nitrosoglutathione Solution Decreases Inflammation And Bone Resorption In Experimental Periodontal Disease In Rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)S-nitrosoglutathione (GSNO) is a nitric oxide (NO) donor, which exerts antioxidant, anti-inflammatory, and microbicidal actions. Intragingival application of GSNO was already shown to decrease alveolar bone loss, inflammation and oxidative stress in an experimental periodontal disease (EPD) model. In the present study, we evaluated the potential therapeutic effect of topical applications of hydroxypropylmethylcellulose (HPMC)/GSNO solutions on EPD in Wistar rats. EPD was induced by placing a sterilized nylon (3.0) thread ligature around the cervix of the second left upper molar of the animals, which received topical applications of a HPMC solutions containing GSNO 2 or 10 mM or vehicle (HPMC solution), 1 h prior to the placement of the ligature and then twice daily until sacrifice on day 11. Treatment with HPMC/ GSNO 10 mM solution significantly reduced alveolar bone loss, oxidative stress and TNF-alpha e IL-1 beta levels in the surrounding gingival tissue, and led to a decreased transcription of RANK and TNF-alpha genes and elevated bone alkaline phosphatase, compared to the HPMC group. In conclusion, topical application of HPMC/GSNO solution is a potential treatment to reduce inflammation and bone loss in periodontal disease.11National Council for Scientific and Technological Development - CNPq [478380/2011-9, 309390/2011-7]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Effect of venlafaxine on bone loss associated with ligature-induced periodontitis in Wistar rats

<p>Abstract</p> <p>Background</p> <p>The present study investigated the effects of venlafaxine, an antidepressant drug with immunoregulatory properties on the inflammatory response and bone loss associated with experimental periodontal disease (EPD).</p> <p>Materials and Methods</p> <p>Wistar rats were subjected to a ligature placement around the second upper left molar. The treated groups received orally venlafaxine (10 or 50 mg/kg) one hour before the experimental periodontal disease induction and daily for 10 days. Vehicle-treated experimental periodontal disease and a sham-operated (SO) controls were included. Bone loss was analyzed morphometrically and histopathological analysis was based on cell influx, alveolar bone, and cementum integrity. Lipid peroxidation quantification and immunohistochemistry to TNF-α and iNOS were performed.</p> <p>Results</p> <p>Experimental periodontal disease rats showed an intense bone loss compared to SO ones (SO = 1.61 ± 1.36; EPD = 4.47 ± 1.98 mm, p < 0.001) and evidenced increased cellular infiltration and immunoreactivity for TNF-α and iNOS. Venlafaxine treatment while at low dose (10 mg/kg) afforded no significant protection against bone loss (3.25 ± 1.26 mm), a high dose (50 mg/kg) caused significantly enhanced bone loss (6.81 ± 3.31 mm, p < 0.05). Venlafaxine effectively decreased the lipid peroxidation but showed no significant change in TNF-α or iNOS immunoreactivity.</p> <p>Conclusion</p> <p>The increased bone loss associated with high dose venlafaxine may possibly be a result of synaptic inhibition of serotonin uptake.</p

Is there a Rationale for the Use of Lymecycline for Frontal Fibrosing Alopecia?

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