The Influence of Nitrogen Fertilization on Growth, Yield and Nitrate and Oxalic Acid Concentration in Purslane (Portulaca oleracea)

Abstract Culinary use of purslane (Portulaca oleracea L.) is appreciated across the whole of the Mediterranean, and the interest in this plant has been increasing due to be a source of bio-protectives compounds, such as fatty acids and antioxidants. However, their use may be difficult due to the accumulation of high contents of compounds harmful to human health, such as nitrate and oxalic acid. The main objective of the present study was to evaluate the influence of nitrogen fertilization on growth and yield parameters, and on nitrate and oxalic acid concentration in leaves and stems. Plants of golden-leafed purslane of sativa subspecies were grown in styrofoam boxes with substrate and fertigated 2 times per week along 4 weeks with ammonium-nitrate solution (16.9% NO3--N and 17.6% NH4+-N), for testing 4 nitrogen levels (0, 30, 60 and 90 kg N ha-1). Plant growth, yield, nitrate and oxalic acid concentrations were significantly affected by nitrogen application. The best quantity/quality ratio was achieved in fertilization level of 60 kg N ha-1, in which the yield was 5.1 kg m-2 FW and nitrate concentration was 48.98 and 43.90 mg g-1 DW in leaf and stem, respectively, and oxalic acid concentration was 1.27 and 0.55 mg g-1 DW, in leaf and stem, respectively, values not harmful to consumer health

Robust LHC Higgs Search in Weak Boson Fusion

We demonstrate that an LHC Higgs search in weak boson fusion production with subsequent decay to weak boson pairs is robust against extensions of the Standard Model or MSSM involving a large number of Higgs doublets. We also show that the transverse mass distribution provides unambiguous discrimination of a continuum Higgs signal from the Standard Model.Comment: 12p, 2 figs., additional comments on backgrounds, version to appear in PR

Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy

We review HB stars in a broad astrophysical context, including both variable and non-variable stars. A reassessment of the Oosterhoff dichotomy is presented, which provides unprecedented detail regarding its origin and systematics. We show that the Oosterhoff dichotomy and the distribution of globular clusters (GCs) in the HB morphology-metallicity plane both exclude, with high statistical significance, the possibility that the Galactic halo may have formed from the accretion of dwarf galaxies resembling present-day Milky Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the second-parameter problem is presented. A technique is proposed to estimate the HB types of extragalactic GCs on the basis of integrated far-UV photometry. The relationship between the absolute V magnitude of the HB at the RR Lyrae level and metallicity, as obtained on the basis of trigonometric parallax measurements for the star RR Lyrae, is also revisited, giving a distance modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are studied. Finally, the conductive opacities used in evolutionary calculations of low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and Space Scienc