Effects of Potassium Source and Secondary Nutrients on Potato Yield and Quality in Southcentral Alaska.

Calcium (Ca), magnesium (Mg), and sulfur (S) are required for the growth and development of all higher plants. They are commonly referred to as secondary nutrients because they are less often limiting to plant growth than the primary nutrients nitrogen (N), phosphorus (P), and potassium (K), although secondary nutrients are as critical for crop growth and development as the primary nutrients. There is limited information available concerning secondary nutrient requirements of potatoes grown in southcentral Alaska. Laughlin (1966) conducted studies between 1961 and 1963 comparing potassium chloride (KCl) and potassium sulfate (K2SO4) as potassium sources for Green Mountain potatoes, and determined the effects of varying rates of magnesium sulfate (MgSO4) and K2SO4 on Kennebec potatoes. Since these studies were conducted without irrigation and at production levels about one-half those obtained by top producers in the Matanuska Valley today, it was considered appropriate to expand upon the previous work using current production practices. Potassium was supplied as KCl and K2 SO4 to explore the need for additional S under local potato production conditions and to determine the effects of the chloride (Cl) and sulfate (SO4) anions on production and quality of potato tubers. In addition, Mg and Ca were added to determine whether the background levels of these nutrients were adequate for optimum production

On Effective Spacetime Dimension in the Ho\v{r}ava-Lifshitz Gravity

In this manuscript we explicitly compute the effective dimension of spacetime in some backgrounds of Ho\v{r}ava-Lifshitz (H-L) gravity. For all the cases considered, the results are compatible with a dimensional reduction of the spacetime to $d+1=2$, at high energies (ultraviolet limit), which is confirmed by other quantum gravity approaches, as well as to $d+1=4$, at low energies (infrared limit). This is obtained by computing the free energy of massless scalar and gauge fields. We find that the only effect of the background is to change the proportionality constant between the internal energy and temperature. Firstly, we consider both the non-perturbative and perturbative models involving the matter action, without gravitational sources but with manifest time and space symmetry breaking, in order to calculate modifications in the Stephan-Boltzmann law. When gravity is taken into account, we assume a scenario in which there is a spherical source with mass $M$ and radius $R$ in thermal equilibrium with radiation, and consider the static and spherically symmetric solution of the H-L theory found by Kehagias-Sfetsos (K-S), in the weak and strong field approximations. As byproducts, for the weak field regime, we used the current uncertainty of the solar radiance measurements to establish a constraint on the $\omega$ free parameter of the K-S solution. We also calculate the corrections, due to gravity, to the recently predicted attractive force that black bodies exert on nearby neutral atoms and molecules.Comment: references adde

Type 2 diabetes, depressive symptoms and trajectories of cognitive decline in a national sample of community-dwellers: a prospective cohort study

We examined the individual and synergistic effects of type 2 diabetes and elevated depressive symptoms on memory and executive function trajectories over 10 and eight years of follow-up, respectively. Our sample comprised 10,524 community-dwellers aged ≥50 years in 2002±03 from the English Longitudinal Study of Ageing. With respect to memory (word recall), participants with either diabetes or elevated depressive symptoms recalled significantly fewer words compared with those free of these conditions (reference category), but more words compared with those with both conditions. There was a significant acceleration in the rate of memory decline in participants aged ≤50±64 years with both conditions (-0.27, 95% CI, -0.45 to -0.08, per study wave), which was not observed in those with either condition or aged ≥65 years. With respect to executive function (animal naming), participants aged 65 years with diabetes or those with elevated depressive symptoms named significantly fewer animals compared with the reference category, while those with both conditions named fewer animals compared with any other category. The rate of executive function decline was significantly greater in participants with both conditions (-0.54, 95% CI, -0.99 to -0.10; and ±0.71, 95% CI, -1.16 to -0.27, per study wave, for those aged 50±64 and ≥65 years, respectively), but not in participants with either condition. Diabetes and elevated depressive symptoms are inversely associated with memory and executive function, but, individually, do not accelerate cognitive decline. The co-occurrence of diabetes and elevated depressive symptoms significantly accelerates cognitive decline over time, especially among those aged 50±64 years

Photon mass as a probe to extra dimensions

In this manuscript we show that the geometrical localization mechanism implies a four dimensional mass for the photon. The consistence of the model provides a mass given exactly by $m_{\gamma}=\sqrt{R}/4$ where $R$ is the Ricci scalar. As a consequence, the cosmological photon has a mass related to the vacuum solution of the Einstein equation. At the present age of the universe we have a dS vacuum with $R=4\Lambda$, where Lambda is a positive cosmological constant. With this we find that $m_{\gamma}\approx 2\times 10^{-69}$ kg, which is below the present experimental upper bounds, and such correction may be observed in the next years with more precise measurements. By considering the value of $R$ inside some astrophysical sources and environments we find that the bound is also satisfied. The experimental verification of this mass, beyond pointing to the existence of extra dimensions, would imply in a fundamental change in cosmology, astrophysics and in particle physics since the same mechanism is valid for non-abelian gauge fields.Comment: 4 page

Dependence of the Black-body Force on Spacetime Geometry and Topology

In this paper we compute the corrections to the black-body force (BBF) potential due to spacetime geometry and topology. This recently discovered attractive force on neutral atoms is caused by the thermal radiation emitted from black bodies and here we investigate it in relativistic gravitational systems with spherical and cylindrical symmetries. For some astrophysical objects we find that the corrected black-body potential is greater than the flat case, showing that this kind of correction can be quite relevant when curved spaces are considered. Then we consider four cases: The Schwarzschild spacetime, the global monopole, the non-relativistic infinity cylinder and the static cosmic string. For the spherically symmetric case of a massive body, we find that two corrections appear: One due to the gravitational modification of the temperature and the other due to the modification of the solid angle subtended by the atom. We apply the found results to a typical neutron star and to the Sun. For the global monopole, the modification in the black-body potential is of topological nature and it is due to the central solid angle deficit that occurs in the spacetime generated by that object. In the cylindrical case, which is locally flat, no gravitational correction to the temperature exists, as in the global monopole case. However, we find the curious fact that the BBF depends on the topology of the spacetime through the modification of the azimuthal angle and therefore of the solid angle. For the static cosmic string we find that the force is null for the zero thickness case.Comment: 8 pages, 5 figures. Revised versio