Intra- and Interspecific Secondary Metabolite Variation Between Fruit and Leaf Tissues in the Hyperdiverse Psychotria Genus

Secondary metabolites are chemical compounds that are considered to mediate a variety of plant interactions with their environment and are not involved in basic metabolism. Recently, there has been an interest in understanding the function and allocation of these metabolites in fruit tissues. In contrast to leaves, the chemistry in fruit tissue mediates exclusive interactions with seed dispersers that directly affect plant fitness and are under different evolutionary selective pressures. Only a few studies outline the patterns of chemistry between fruit and leaf tissues. This study aims to understand how secondary metabolites in two species of the hyperdiverse congeneric genus (Psychotria) differ between fruit and leaf tissues within each species, how plant tissue chemistry differs across species, and what implications this has for ecological interactions, seed dispersal, and the understanding of evolutionary processes. Plant samples from seed, leaf, and pulp tissue were collected from two species of the hyperdiverse Psychotria genus, P. marginata and P. limonensis. Plant samples were collected in a Neotropical forest on Barro Colorado Island in Panama. The secondary metabolites from these plant tissues were extracted using a [99.9: 0.1] ethanol to formic acid solution. The plant extracts will be analyzed using liquid chromatography coupled with mass spectrometry methods. The data will then further be analyzed using novel modeling methods to elucidate and compare the chemical structural diversity of each tissue and species. Within species, I predict the chemical makeup of leaf tissues is different than that of pulp and seed tissues. This would further support the hypothesis that secondary metabolites in fruit tissues have an adaptive function. Across species, I predict that the differences in secondary metabolite diversity in leaf tissues will be greater than the differences within species. These results would suggest an evolutionary mechanism in which defensive leaf chemistry is selected upon. This selection of leaf chemistry contributes to the diversification of the genus to fill novel niches and allows for the hyperdiverse genus to coexist within a small area. Though the chemistry between the leaf tissues is predicted to be divergent when compared across species, the question remains if this trend will be exhibited in fruits. I predict that fruit tissue chemistry will be similar between species in order to conserve the important function these metabolites play in mediating interactions with the same seed disperser within the genus. This study will lead to a better understanding of the evolutionary selective processes imposed on different plant tissues and the significance that these metabolites play in the diversification of plant genera

Experimental and Theoretical Results for Weak Charge Current Backward Proton Production

In this paper, we do three things in the study of deuteron break-up by high energy neutrino beams. (1) We present previously unpublished data on neutrino induced backward protons from deuteron targets; (2) we calculate the contributions from both the two-nucleon (2N) and six-quark (6q) deuteron components, which depend upon the overall normalization of the part that is 6q; and (3) we suggest other signatures for distinguishing the 2N and 6q clusters. We conclude that the 6q cluster easily explains the shape of the high momentum backward proton spectrum, and its size is nicely explained if the amount of 6q is one or a few percent by normalization of the deuteron. There is a crossover, above which the 6q contribution is important or dominant, at 300--400 MeV/c backward proton momentum.Comment: 8 pages, 5 figure

The Antidepressant and Anxiolytic Effects of Cannabinoids in Chronic Unpredictable Stress: A Preclinical Systematic Review and Meta-Analysis

Neuroscience research presents contradictory evidence in support of both the protective and destructive effects of cannabinoids in depression. Therefore, this systematic review and meta-analysis summarizes the existing preclinical literature on the effects of cannabinoid administration in the chronic unpredictable stress model of depression in order to evaluate the effects of cannabinoids and identify gaps in the literature. After protocol registration (PROSPERO #CRD42020219986), we systematically searched Scopus, Embase, Psychology & Behavioral Sciences Collection, APA PsychINFO, PubMed, CINAHL Complete, and ProQuest Dissertations & Theses Global from the earliest record of the databases, February 1964, to November 2020 for articles that met inclusion criteria (e.g., rodent subjects and administration of a cannabinoid. A total of 26 articles were included representing a sample size estimate of 1132 rodents with the majority of articles administering daily intraperitoneal injections during chronic unpredictable stress. These articles were evaluated using a modified SYRCLE\u27s risk-of-bias tool. For each continuous behavioral measure, the standardized mean difference was calculated between cannabinoid and vehicle groups in rodents subjected to chronic unpredictable stress. The effects of cannabinoids on depressive-like behavior was evaluated using a multilevel mixed-effects model with effect size weights nested within control groups. Cannabinoid administration moderately improved the pooled negative effects of chronic unpredictable stress on anhedonia, learned helplessness, novelty suppressed feeding, time in the anxiogenic context, and entries into the anxiogenic context. Although the interpretations are limited, these findings suggest that with further investigation, cannabinoids may be a viable long-term treatment for stress-related psychopathologies such as depression

Star Formation History in two fields of the Small Magellanic Cloud Bar

The Bar is the most productive region of the Small Magellanic Cloud in terms of star formation but also the least studied one. In this paper we investigate the star formation history of two fields located in the SW and in the NE portion of the Bar using two independent and well tested procedures applied to the color-magnitude diagrams of their stellar populations resolved by means of deep HST photometry. We find that the Bar experienced a negligible star formation activity in the first few Gyr, followed by a dramatic enhancement from 6 to 4 Gyr ago and a nearly constant activity since then. The two examined fields differ both in the rate of star formation and in the ratio of recent over past activity, but share the very low level of initial activity and its sudden increase around 5 Gyr ago. The striking similarity between the timing of the enhancement and the timing of the major episode in the Large Magellanic Cloud is suggestive of a close encounter triggering star formation.Comment: 30 pages, 22 figures, accepted for publication in Ap

The most recent burst of Star Formation in the Massive Elliptical Galaxy NGC 1052

High-spatial resolution near-infrared (NIR) images of the central 24 x 24 arcsec^2 (~ 2 x 2 kpc^2) of the elliptical galaxy NGC 1052 reveal a total of 25 compact sources randomly distributed in the region. Fifteen of them exhibit Halpha luminosities an order of magnitude above the estimate for an evolved population of extreme horizontal branch stars. Their Halpha equivalent widths and optical-to-NIR spectral energy distributions are consistent with them being young stellar clusters aged < 7 Myr. We consider this to be the first direct observation of spatially resolved star-forming regions in the central kiloparsecs of an elliptical galaxy. The sizes of these regions are ~< 11 pc and their median reddening is E(B - V) ~ 1 mag. According to previous works, NGC 1052 may have experienced a merger event about 1 Gyr ago. On the assumption that these clusters are spreaded with similar density over the whole galaxy, the fraction of galaxy mass (5 x 10^{-5}) and rate of star formation (0.01 Msun/yr) involved, suggest the merger event as the possible cause for the star formation we see today.Comment: 5 pages, 3 figures. Accepted for publication in MNRAS Letter

Towards an accurate model of the redshift space clustering of halos in the quasilinear regime

Observations of redshift-space distortions in spectroscopic galaxy surveys offer an attractive method for measuring the build-up of cosmological structure, which depends both on the expansion rate of the Universe and our theory of gravity. Galaxies occupy dark matter halos, whose redshift space clustering has a complex dependence on bias that cannot be inferred from the behavior of matter. We identify two distinct corrections on quasilinear scales (~ 30-80 Mpc/h): the non-linear mapping between real and redshift space positions, and the non-linear suppression of power in the velocity divergence field. We model the first non-perturbatively using the scale-dependent Gaussian streaming model, which we show is accurate at the <0.5 (2) per cent level in transforming real space clustering and velocity statistics into redshift space on scales s>10 (s>25) Mpc/h for the monopole (quadrupole) halo correlation functions. We use perturbation theory to predict the real space pairwise halo velocity statistics. Our fully analytic model is accurate at the 2 per cent level only on scales s > 40 Mpc/h. Recent models that neglect the corrections from the bispectrum and higher order terms from the non-linear real-to-redshift space mapping will not have the accuracy required for current and future observational analyses. Finally, we note that our simulation results confirm the essential but non-trivial assumption that on large scales, the bias inferred from real space clustering of halos is the same one that determines their pairwise infall velocity amplitude at the per cent level.Comment: 15 pages, 12 figures, submitted to MNRA

Interpreting large-scale redshift-space distortion measurements

The simplest theory describing large-scale redshift-space distortions (RSD), based on linear theory and distant galaxies, depends on the growth of cosmological structure, suggesting that strong tests of General Relativity can be constructed from galaxy surveys. As data sets become larger and the expected constraints more precise, the extent to which the RSD follow the simple theory needs to be assessed in order that we do not introduce systematic errors into the tests by introducing inaccurate simplifying assumptions. We study the impact of the sample geometry, non-linear processes, and biases induced by our lack of understanding of the radial galaxy distribution on RSD measurements. Using LasDamas simulations of the Sloan Digital Sky Survey II (SDSS-II) Luminous Red Galaxy (LRG) data, these effects are shown to be important at the level of 20 per cent. Including them, we can accurately model the recovered clustering in these mock catalogues on scales 30 -- 200 Mpc/h. Applying this analysis to robustly measure parameters describing the growth history of the Universe from the SDSS-II data, gives $f(z=0.25)\sigma_8(z=0.25)=0.3512\pm0.0583$ and $f(z=0.37)\sigma_8(z=0.37)=0.4602\pm0.0378$ when no prior is imposed on the growth-rate, and the background geometry is assumed to follow a $\Lambda$CDM model with the WMAP + SNIa priors. The standard WMAP constrained $\Lambda$CDM model with General Relativity predicts $f(z=0.25)\sigma_8(z=0.25)=0.4260\pm0.0141$ and $f(z=0.37)\sigma_8(z=0.37)=0.4367\pm0.0136$, which is fully consistent with these measurements.Comment: 20 pages, 17 figures, 1 tabl

BDM Dark Matter: CDM with a core profile and a free streaming scale

We present a new dark matter model BDM which is an hybrid between hot dark matter HDM and cold dark matter CDM, in which the BDM particles behave as HDM above the energy scale E_c and as CDM below this scale. Evolution of structure formation is similar to that of CDM model but BDM predicts a nonvanishing free streaming l_fs scale and a inner galaxy core radius r_core, both quantities determined in terms of a single parameter E_c, which corresponds to the phase transition energy scale of the subjacent elementary particle model. For energies above E_c or for a scale factor a smaller then a_c, with a<a_c<a_{eq}, the particles are massless and rho redshifts as radiation. However, once the energy becomes E\leq E_c or a>a_c then the BDM particles acquire a large mass through a non perturbative mechanism, as baryons do, and rho redshifts as matter with the particles having a vanishing velocity. Typical energies are E_c=O(10-100) eV giving a l_fs \propto E_c^{-4/3}\lesssim Mpc and m_fs\propto E_c^{-4}\lesssim 10^9 M\odot. A l_fs\neq 0, r_core\neq 0 help to resolve some of the shortcomings of CDM such as overabundance substructure in CDM halos and numerical fit to rotation curves in dwarf spheroidal and LSB galaxies. Finally, our BDM model and the phase transition scale E_c can be derived from particle physics.Comment: 7 pages, 8 figure