Self lensing effects for compact stars and their mass-radius relation

During the last couple of years astronomers and astrophysicists have been debating on the fact whether the so called `strange stars' - stars made up of strange quark matter, have been discovered with the candidates like SAX J1808.4-3658, 4U 1728-34, RX J1856.5-3754, etc. The main contention has been the estimation of radius of the star for an assumed mass of ~ 1.4 M_sun and to see whether the point overlaps with the graphs for the neutron star equation of state or whether it goes to the region of stars made of strange matter equation of state. Using the well established formulae from general relativity for the gravitational redshift and the `lensing effect' due to bending of photon trajectories, we, in this letter, relate the parameters M and R with the observable parameters, the redshift z and the radiation radius R_\infty, thus constraining both M and R for specific ranges, without any other arbitrariness. With the required inputs from observations, one ought to incorporate the effects of self lensing of the compact stars which has been otherwise ignored in all of the estimations done so far. Nonetheless, these effect of self lensing makes a marked difference and constraints on the M-R relation.Comment: 7 pages, 1 figure, accepted for publication in Mod. Phys. Lett.

Encapsulation of Bifidobacterium longum in alginate-dairy matrices and survival in simulated gastrointestinal conditions, refrigeration, cow milk and goat milk

The aim of this study was to microencapsulate Bifidobacterium longum subsp. infantis CCUG 52486 using the extrusion method in a variety of matrices, namely sodium alginate (SA), sodium alginate-cow milk (SACM), sodium alginate-goat milk (SAGM) and sodium alginate-casein hydrolysate (SACH), and to evaluate the survival of free and encapsulated bacterial cells under different conditions. The encapsulation yield, size and surface morphology of the microcapsules were evaluated. The survival of microencapsulated bacterial cells and free bacterial cells were evaluated under simulated gastrointestinal conditions as well as in refrigeration, cow milk and goat milk during storage at 4 oC for 28 days. The average size of SACM capsules and SAGM capsules was 2.8±0.3 mm and 3.1±0.2 mm respectively. Goat milk and cow milk based matrices resulted in dense microcapsules which led to better performances in simulated gastrointestinal conditions than SA and SACH microcapsules. The bacterial cells encapsulated in SAGM showed the highest survival rate in cow milk (7.61 log cfu g-1) and goat milk (8.10 log cfu g-1) after the storage of 28 d. The cells encapsulated in SA and SACH and the free cells performed poorly under the simulated gastrointestinal conditions and in all different storage conditions. This study showed that SACM and SAGM are suitable to encapsulate B. longum subsp. infantis CCUG 52486 using the extrusion technique and more specifically, SAGM has a potential to be used as a new encapsulation material for encapsulating probiotic bacteria, resulting milk and goat milk-based products with higher probiotic cell concentrations during refrigerated storage

An Analysis of the Role of Tile-Drained Farmland Under Alternative Nitrogen Abatement Policies

Agricultural nitrogen is a major contributor to Gulf of Mexico hypoxia, and research has shown that agricultural subsurface tile drainage is a major carrier of nitrogen from croplands to streams and rivers. This study compares the results of abating nitrogen under a retired-land minimization policy with those of a new revenue-maximizing policy, paying particular attention to the role of tile-drained land. Findings reveal the retirement-minimizing policy resulted in more tile-drained land being retired and less being fertilizer-managed than was optimal under the net-return maximizing policy. Also, it led to a greater economic burden being shouldered by tile-drained land. Under both cases, tile drainage dominated the abatement process.abatement, ADAPT, drainage, hypoxia, nitrogen, Crop Production/Industries, Land Economics/Use,

Maximum life spiral bevel reduction design

Optimization is applied to the design of a spiral bevel gear reduction for maximum life at a given size. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial values. Gear tooth bending strength and minimum contact ratio under load are included in the active constraints. The optimal design of the spiral bevel gear reduction includes the selection of bearing and shaft proportions in addition to gear mesh parameters. System life is maximized subject to a fixed back-cone distance of the spiral bevel gear set for a specified speed ratio, shaft angle, input torque, and power. Significant parameters in the design are: the spiral angle, the pressure angle, the numbers of teeth on the pinion and gear, and the location and size of the four support bearings. Interpolated polynomials expand the discrete bearing properties and proportions into continuous variables for gradient optimization. After finding the continuous optimum, a designer can analyze near optimal designs for comparison and selection. Design examples show the influence of the bearing lives on the gear parameters in the optimal configurations. For a fixed back-cone distance, optimal designs with larger shaft angles have larger service lives

Backaction-Driven Transport of Bloch Oscillating Atoms in Ring Cavities

We predict that an atomic Bose-Einstein condensate strongly coupled to an intracavity optical lattice can undergo resonant tunneling and directed transport when a constant and uniform bias force is applied. The bias force induces Bloch oscillations, causing amplitude and phase modulation of the lattice which resonantly modifies the site-to-site tunneling. For the right choice of parameters a net atomic current is generated. The transport velocity can be oriented oppositely to the bias force, with its amplitude and direction controlled by the detuning between the pump laser and the cavity. The transport can also be enhanced through imbalanced pumping of the two counter-propagating running wave cavity modes. Our results add to the cold atoms quantum simulation toolbox, with implications for quantum sensing and metrology.Comment: Published version: 5 pages, 4 figures; Supplementary Material include

Targeting Agricultural Drainage to Reduce Nitrogen Losses in a Minnesota Watershed

Agricultural nitrogen losses are the major contributor to nitrogen loads in the Mississippi River, and consequently, to the existence of a hypoxic, or dead, zone in the Gulf of Mexico. Focusing on two small agricultural watersheds in southeast Minnesota, simulation results from the Agricultural Drainage And Pesticide Management (ADAPT) model were combined with a linear-optimization model to evaluate the environmental and economic impact of alternative land-use policies for reducing nitrogen losses. Of particular importance was the studys explicit focus on agricultural subsurface (tile) drainage, which has been identified as the major pathway for agricultural nitrogen losses in the upper Midwest, and the use of drainage-focused abatement policies. Results indicate that tile-drained land plays a key role in nitrogen abatement, and that a combined policy of nutrient management on tile-drained land and retirement of non-drained land is a cost-effective means of achieving a 20- or 30-percent nitrogen-abatement goal. Results also indicate that although it is cost-effective to abate on tile-drained land, it is not cost-effective to undertake policies that plug or remove tile drains from the landscape, regardless of whether the land would be retired or kept in production. Therefore, results imply that although tile-drained land is a major source of nitrogen lost to waterways, it is not cost-effective to remove the land from production or to remove the drainage from the land. Because of its value to agricultural production, it is better to keep tile-drained land in production under nutrient management and focus retirement policies on relatively less-productive, non-drained acres.Environmental Economics and Policy, Land Economics/Use,

On relating brain shape with neurological disorders

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Encapsulation in an alginate–goats’ milk–inulin matrix improves survival of probiotic Bifidobacterium in simulated gastrointestinal conditions and goats’ milk yoghurt

In this work, a new encapsulating matrix, alginate–goats’ milk–inulin, was used to encapsulate Bifidobacterium animalis subsp. lactis BB‐12. The addition of inulin resulted in capsules with a compact structure, and a higher probiotic cell count under simulated gastrointestinal conditions and in probiotic goats’ milk yoghurt during refrigerated storage. Encapsulation of the probiotic bacteria led to slower post‐acidification yoghurts. The results of this study showed that the alginate–goats’ milk–inulin matrix has potential to be used as a new encapsulation material to encapsulate probiotics for use in goats’ milk‐based probiotic fermented dairy products, avoiding the cross‐contamination caused by using capsules based on cows’ milk