Spectral Methods from Tensor Networks

A tensor network is a diagram that specifies a way to "multiply" a collection of tensors together to produce another tensor (or matrix). Many existing algorithms for tensor problems (such as tensor decomposition and tensor PCA), although they are not presented this way, can be viewed as spectral methods on matrices built from simple tensor networks. In this work we leverage the full power of this abstraction to design new algorithms for certain continuous tensor decomposition problems. An important and challenging family of tensor problems comes from orbit recovery, a class of inference problems involving group actions (inspired by applications such as cryo-electron microscopy). Orbit recovery problems over finite groups can often be solved via standard tensor methods. However, for infinite groups, no general algorithms are known. We give a new spectral algorithm based on tensor networks for one such problem: continuous multi-reference alignment over the infinite group SO(2). Our algorithm extends to the more general heterogeneous case.Comment: 30 pages, 8 figure

High speed shadowgraphy for the study of liquid drops

The book contains invited lectures and selected contributions presented at the Enzo Levi and XVII Annual Meeting of the Fluid Dynamic Division of the Mexican Physical Society in 2011.This was work was sponsored by EPSRC grant number RG5560

Novel designs for Penning ion traps

We present a number of alternative designs for Penning ion traps suitable for quantum information processing (QIP) applications with atomic ions. The first trap design is a simple array of long straight wires which allows easy optical access. A prototype of this trap has been built to trap Ca+ and a simple electronic detection scheme has been employed to demonstrate the operation of the trap. Another trap design consists of a conducting plate with a hole in it situated above a continuous conducting plane. The final trap design is based on an array of pad electrodes. Although this trap design lacks the open geometry of the traps described above, the pad design may prove useful in a hybrid scheme in which information processing and qubit storage take place in different types of trap. The behaviour of the pad traps is simulated numerically and techniques for moving ions rapidly between traps are discussed. Future experiments with these various designs are discussed. All of the designs lend themselves to the construction of multiple trap arrays, as required for scalable ion trap QIP.Comment: 11 pages, 10 figure

Dynamic nozzles for drop generators

received: 2015-06-03 accepted: 2015-10-16 published: 2015-11-03received: 2015-06-03 accepted: 2015-10-16 published: 2015-11-03This work was funded by the UK Engineering and Physical Sciences Research Council (Grant No. EP/H018913/1), the John Fell Oxford University Press Research Fund, and the Royal Society

Nasca Lines: A Mystery wrapped in an Enigma

We analyze the geometrical structure of the astonishing Nasca geoglyphs in terms of their fractal dimension with the idea of dating these manifestations of human cultural engagements in relation to one another. Our findings suggest that the first delineated images consist of straight, parallel lines and that having sophisticated their abilities, Nasca artist moved on to the design of more complex structures.Comment: 6 pages, 1 color figure and 2 graphs. To appear in Chao

Biodiesel Dari Campuran Lemak Sapi (Beef Tallow) Dan Minyak Sawit

Cadangan minyak bumi semakin menipis, sehingga dicari bahan bakar alternatif, salah satunya adalah biodiesel. Minyak nabati terutama minyak sawit merupakan bahan baku edible sedangkan lemak sapi merupakan bahan baku non-edible dengan biaya rendah dan memiliki ketersediaan tinggi pada produksi sapi. Pemanfaatan lemak sapi yang belum maksimal dapat digunakan bersama minyak sawit untuk menghasilkan biodiesel. Lemak sapi dicairkan supaya menjadi minyak sapi. Bahan baku minyak sapi dan minyak sawit dicampur dengan perban-dingan 3:1. Campuran minyak ditransesterifikasi dengan metanol dengan perbandingan molar (1:6) dan katalis NaOH. Proses dilakukan selama 90 menit pada suhu ±65°C. Hasil proses transesterifikasi adalah metil ester dan gliserol. Metil ester pada lapisan atas dipisahkan dari gliserol kemudian dilakukan pencucian. Metil ester atau biodiesel selanjutnya diuji angka asam, viskositas, densitas, dan analisis menggunakan GC-MS. Yield biodiesel yang dihasilkan dari campuran minyak sapi dan minyak sawit adalah 76%, angka asam 0,67124 mg-KOH/g, densitas 857,76 kg/cm³, dan viskositas 3,0074 mm2/s. Kesemua parameter tersebut sesuai dengan standart mutu SNI biodiesel. Kandungan metil ester dari minyak sawit dan lemak sapi adalah metiloleat dan metil palmitat. The availability of the fossil fuel is decreasing; hence the finding of an alternative fuels is very important. One of those alternative fuels is biodiesel. Vegetable oil, especially palm oil is the edible raw material, while the beef tallow is the non-edible raw material with low cost production and the availability is huge in the cattle production. The beef tallow mixed with palm oil can be used as raw material for producing biodiesel. Firstly, the beef tallow was melted into beef oil. The raw materials of beef tallow and palm oil were mixed with the composition ratio of 3:1. The resulted mixed-oil was transesterificated by adding methanol with molar ratio of 1:6 and NaOH as catalyst. The transesterification process was carried for 90 minutes at ±65°C. Transesterification process produces methyl ester and glycerol. The produced methyl ester on the upper layer was separated from the glycerol and then washed. The produced methyl ester was tested to determine the acid number, viscosity, and density. Analysis of the methyl ester components using GC-MS was also conducted. The experimental results show the yield of produced biodiesel from mixed-oil of beef tallow and palm oil (3:1) was 75.93%. The tested acid number, density, and viscosity were 0.67124 mg-KOH/g, 85.76 kg/cm³, and 3.0074 mm2/s, respectively. Data of the tested methyl ester properties are in accordance with the quality of standard ISO for methyl ester. The content of the produced methyl ester from the mixed-oil of beef tallow and palm oil are metiloleat and methyl palmitate

Comparative study of toxicological effects of lindane and isoproturon pesticides in the Saccharomyces cerevisiae

Organochlorine insecticides and phenylurea herbicides such as lindane (hexachlorocyclo-hexane, γ-HCH) and isoproturon (3-(4-isopropylphenyl)-1,1-dimethylurea, IPU), used in agricultural applications for the pest and broad-leaved control, are often found in contaminated groundwater and surface water. Unfortunately, the toxicity of these pesticides in eukaryotic cells is still poorly understood. Saccharomyces cerevisiae is a promising eukaryotic organism for the toxicological evaluation of pollutants, because its metabolism is similar to that of high-level organisms. Thus the aim of this study was to compare the effects of two pesticides on yeast-cell viability and its antioxidant power. S. cerevisiae UE-ME3, a wild-type strain belonging to Oenology Laboratory of the University of Évora, grown in the presence of 50 μM γ-HCH and 100 μM IPU in 2% glucose and peptone deprivation medium (YED), at 28 °C were compared with control cells. CFU were determined at the end of the experiment and remaining cells disintegrated in 10 mM phosphate buffer pH 7.0 by sonication. Post-12,000 × g supernatant was used for determination of glutathione (GSH), glutathione disulphide (GSSG) and malondialdehyde (MDA) content and glutathione reductase (GR), glutathione peroxidase (GPx) and cytoplasmic catalase (CTT1) activity. The results showed that 50 μM γ-HCH exposures, in YED medium, did not affect cell viability, CTT1 activity, non-protein thiols (GSH + GSSG) and MDA content of S. cerevisiae. However, the 50 μM γ-HCH exposure caused a decrease in GSH/GSSG ratio, GR and GPx activity. In contrast, 100 μM IPU exposures caused an increase in the cell viability, (GSH + GSSG), GSH/GSSG ratio and GR activity. Additionally, there was a decrease in the MDA levels, GPx and CTT1 activity, under the same growth conditions. In conclusion, the presence of lindane, in YED medium, caused a reducing-oxidizing transition, a slowdown of the glutathione redox cycle without disturbing the survival of S. cerevisiae. However, the increase in the cell viability, the redox buffer power and the lipid peroxidation attenuation caused by IPU in nitrogen deprivation, appears to be due to the high regeneration capacity of GSH via GR activity, pointing out a possible use of isoproturon as nitrogen source

Reservas de Caza en España: la gestión pública de la caza

In Spain, Game Reserves (GR) are territorial public hunting management units that cover 3.5% of the country and ~ 10% of the Natura 2000 Network. The first GR were established in 1966 and by 2011 there were 49. Their primary purposes were to promote wild ungulate populations, their sustainable use, and to provide social, economic, and recreational benefits to local communities and hunters, generally. During the 1980s following a political federalization process, GR became the responsibility of regional governments and their role has never been evaluated, even though the political, rural ecological, and administrative frameworks underwent substantial changes. In this paper, we present a review of the state of GR in 2011, identify their successes and problems, and provide recommendations for the future. The GR have been fundamental to sustainable hunting and the protection of wildlife, particularly, game species. Currently, their virtues are not widely appreciated and they do not receive sufficient financial and human resources to meet their objective fully. We propose several initiatives that might improve the use of existing resources and increase the profile of these publicly managed areas.Las Reservas de Caza (RC) constituyen una figura de gestión cinegética pública del territorio en España. Abarcan el 3.5% del territorio y ocupan aproximadamente el 10% de la Red Natura 2000. Su declaración comenzó en 1966, y desde entonces no ha cesado, llegando en la actualidad a las 49 RC. Fueron creadas esencialmente para la promoción de las poblaciones de ungulados silvestres, el aprovechamiento ordenado de este recurso y la satisfacción social, económica y recreativa de las comunidades locales y de los cazadores en general. Quedaron fuera de la tutela del estado tras su descentralización a partir de principios de los años ochenta del pasado siglo, y su función en conjunto no ha sido nunca evaluada, al tiempo que el panorama político, rural, ecológico y administrativo ha sufrido profundos cambios. Este artículo pretende ofrecer una panorámica actualizada de la situación de las RC a principios del siglo XXI, evaluar sus logros y problemática actual, así como proponer algunas actuaciones para el futuro inmediato. Las RC han sido pioneras en el aprovechamiento sostenible de la caza y de gran utilidad para la protección de la fauna en general y las especies cinegéticas en concreto. Actualmente no gozan del reconocimiento popular, y no reciben los recursos necesarios económicos y humanos suficientes para seguir cumpliendo su función adecuadamente. Se proponen una serie de medidas para aprovechar mejor los recursos disponibles y poder dar a conocer a la sociedad el valor de estos terrenos de gestión pública