Nonannual tree rings in a climate-sensitive Prioria copaifera chronology in the Atrato River, Colombia

In temperate climates, tree growth dormancy usually ensures the annual nature of tree rings, but in tropical environments, determination of annual periodicity can be more complex. The purposes of the work are as follows: (1) to generate a reliable tree‐ring width chronology for Prioria copaifera Griseb. (Leguminoceae), a tropical tree species dwelling in the Atrato River floodplains, Colombia; (2) to assess the climate signal recorded by the tree‐ring records; and (3) to validate the annual periodicity of the tree rings using independent methods. We used standard dendrochronological procedures to generate the P. copaifera tree‐ring chronology. We used Pearson correlations to evaluate the relationship of the chronology with the meteorological records, climate regional indices, and gridded precipitation/sea surface temperature products. We also evaluated 24 high‐precision 14C measurements spread over a range of preselected tree rings, with assigned calendar years by dendrochronological techniques, before and after the bomb spike in order to validate the annual nature of the tree rings. The tree‐ring width chronology was statistically reliable, and it correlated significantly with local records of annual and October–December (OND) streamflow and precipitation across the upper river watershed (positive), and OND temperature (negative). It was also significantly related to the Oceanic Niño Index, Pacific Decadal Oscillation, and the Southern Oscillation Index, as well as sea surface temperatures over the Caribbean and the Pacific region. However, 14C high‐precision measurements over the tree rings demonstrated offsets of up to 40 years that indicate that P. copaifera can produce more than one ring in certain years. Results derived from the strongest climate–growth relationship during the most recent years of the record suggest that the climatic signal reported may be due to the presence of annual rings in some of those trees in recent years. Our study alerts about the risk of applying dendrochronology in species with challenging anatomical features defining tree rings, commonly found in the tropics, without an independent validation of annual periodicity of tree rings. High‐precision 14C measurements in multiple trees are a useful method to validate the identification of annual tree rings

Effect of Nitrogen on Agronomic Yield, Spad Units and Nitrate Content in Roselle (Hibiscus Sabdariffal.) in Dry Weather

This study was conducted in polyethylene bags of 4 kg capacity with plants of Jamaica from seeds collected from an accession on the coast of Oaxaca, which were planted under the ecological conditions of Teotitlán de Flores Magón, and evaluated under completely randomized design, where treatments were four levels of nitrogen: 0, 50, 100 and 150 kg ha-1 and four repetitions (4x4) = 16 experimental units. The variables evaluated were: both agronomic yields: chalice and seed, harvest index, SPAD units and nitrate content in leaf. The results indicate that higher yields ofseed and chalice, biomass, nitrate content in leaf and SPAD units were achieved with the application of 100 kg ha-1 of nitrogen with 50.39, 196.80, 620.4 g plant-1, 85.00 mg kg-1 and 29.10 units, respectively. The content of nitrates and its relationship with SPAD units, adjusted to an increasing linear model for the four levels of nitrogen studied. From this study it can be concluded that the application of 100 kg N ha-1, positively affect the culture of Jamaica under dry weather conditions way

Should we meet in person or on Facetime? An examination of expectancy violations and predicted outcome value forecasts during online dating modality switches

The present study drew from expectancy violations theory, predicted outcome value (POV) theory, and the modality switching perspective to examine online daters who subsequently met for FtF-like communication. Hierarchical regression analyses tested whether online daters’ post-modality switch (MS) expectedness ratings, evaluations, and POV forecasts were related to their: (a) pre-MS length of online association; (b) number of pre-MS partner photos seen; (c) use of pre-MS phone calls; and (d) decision to hold the first FtF-like meeting in person or through video chat. Behavioral and physical appearance expectedness ratings were positively related to the number of pre-MS partner photos seen, and curvilinearly (inverted-u shape) related to daters’ pre-MS length of association. Physical appearance evaluations were positively associated with the number of pre-MS photos seen, while behavioral and physical appearance evaluations displayed positive associations with pre-MS phone calls. Finally, post-MS POV forecasts were positively associated with the number of pre-MS partner photos seen, holding the MS through video chat, post-MS assessments of a partner’s behavioral expectedness, and post-MS evaluations of a partner’s behavioral and physical appearance. An interaction also emerged for behavioral expectedness and evaluation on POV, which implied that negative expectancy violations were more useful than positive violations in predicting a relationship’s potential viability

Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 $< p_{\rm{T}, assoc} < p_{\rm{T}, trig} <$ 5.0 GeV/$c$ is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range $|\eta|<0.9$. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161