Fluctuations in mental well-being during Study Abroad

This mixed-methods study focuses on the effect of Study Abroad (SA) on the mental well-being of 33 Anglophone students who spent between four and twelve months in Francophone countries. It investigates the relationship between well-being and personality traits. Statistical analyses revealed no significant change in well-being between the start, the middle and the end of the SA. A closer look at individual patterns showed large fluctuations, with half of participants scoring higher and the other half scoring lower between the start and the middle of the SA. The narratives of three participants whose well-being scores increased most were not very different from the three participants whose well-being scores decreased most, and only (lower) Emotional Stability was linked with the increase in well-being. At the group level, well-being was not significantly linked to personality traits. The apparent stability of well-being during SA seems to be the result of upward and downward patterns cancelling each other out.

The structure and organization of an Amazonian bird community remains little changed after nearly four decades

Documenting patterns of spatio-temporal change in hyper-diverse communities remains a challenge for tropical ecology, yet is increasingly urgent as some long-term studies have shown major declines in bird communities even in relatively undisturbed sites. In 1982, Terborgh et al. quantified the structure and organization of the bird community in a 97-ha. plot in southeastern Peru. We revisited the same plot in 2018 and repeated the same intense combination of methodologies as the original study in order to evaluate community-wide changes. Contrary to the results from studies elsewhere, we found little change in bird distribution and abundance within the plot, although there were some declines related to loss of mixed-species flocks with a high level of species interdependence. This apparent stability suggests that large-scale forest reserves such as Manu National Park may provide the conditions necessary for establishing refugia from at least some of the effects of global change on birds.

Coordination Chemistry of a bis(tetrazine) tweezer: A Case of Host-guest Behavior With Silver Salts

The carbon-carbon cross-coupling of phenyl s-tetrazine (Tz) units at their ortho-phenyl positions allows to form constrained bis(tetrazines) with original tweezer structures. In these compounds, the face-to-face positioning of the central tetrazine cores is endorsed by pi-staking of the electron-poor nitrogen-containing heteroaromatic moieties. The resulting tetra-aromatic structure can be used as a weak coordinating ligand with cationic silver. This coordination generates a set of bis(tetrazine)‐silver(I) coordination complexes tolerating a large variety of counter anions of various geometries, namely, PF6–, BF4–, SbF6–, ClO4–, NTf2–, OTf2–. These compounds were characterized in the solid-state by single crystal XRD and reflectance spectra, and in solution by 1H NMR, mass spectrometry, electroanalysis and UV-visible absorption spectroscopy. The X-ray diffraction (XRD) structure of complexes {[Ag(3)][PF6]}∞ (4) and {[Ag(3)][SbF6]∞ (6), where 3 is 3,3'-[(1,1'-biphenyl)-2,2'-diyl]-6,6'-bis[phenyl]-1,2,4,5-tetrazine, revealed the formation of 1D polymeric chains, characterized by an evolution to a large opening of the original tweezer and a coordination of silver(I) via two chelating nitrogen atom and some C=C pi-interactions. Electrochemical and UV spectroscopic properties of the original tweezer and of the corresponding silver complex are reported and compared. 1H NMR titrations with AgNTf2 allowed to determine the stoichiometry, and apparent stability of two solution species, namely [Ag(3)]+ and [Ag(3)2]2+, that formed in CDCl3/CD3OD 2:1 v/v mixtures.

The ghosts of progress: contradictory materialities of the capitalist Golden Age

This theoretical contribution will examine the process of displacement of the constitutive contradictions of advanced capitalist societies from interior to exterior during the postwar era known as the ‘capitalist Golden Age’ (1945 to 1980). I ask the following question: what if this displacement is both an inherent and necessary process? In that case, the apparent stability or expansion gained in the core during this era was not only at the expense of externalized instability and destruction ‘elsewhere’; rather, this displacement was a precondition for growth in the centre. This has normative, political and methodological implications for current projects of socio-ecological transformation based on a proverbial Green New Deal. By examining theories of unequal ecological exchange and biophysically expanded versions of the labour process as developed by ecological anthropologists such as Hornborg or ecological economists such as Georgescu-Roegen, I will explore the possibility of understanding the material trajectory of advanced capitalism as a zero-sum game. This leads to a view of capitalist development in the 20th century where the accumulation process is no longer seen as progressive. To substantiate this argument, I will re-examine the energy flow patterns that sustained the growth of American capitalism during the Fordist period of accumulation, or so-called Golden Age of American capitalism. This revision of the American experience of growth from 1945 to 1980 can be considered a contribution to the wider study of the development of the dependence of capitalism on fossil fuels, or ‘fossil capital’.

Analysis of the population dynamics of the endangered American crocodile, Crocodylus acutus in Paramillo National Natural Park

Few studies have been conducted on the population dynamics of crocodiles, especially in the Neotropics. This is the first study to provide data on the population dynamics of the threatened American crocodile (Crocodylus acutus (Cuvier, 1807)) in Paramillo National Natural Park. Twenty-four survey routes of 22km each were studied, and a total of 733 sightings was recorded. During the study period (from October 2014 to March 2016), the population remained stable and experienced slight growth (λ=1.049±0.428). Offspring production by the adults II stage was the most sensitive contribution (17.05), whereas the permanence of this adult stage was the demographic process that contributed the most to population growth (0.653). However, an 18% decrease in adults II would jeopardise long-term population viability and lead to a high probability of quasi-extinction, with under 300 individuals over the next 30 years. Thus, despite the apparent stability of this population, we suggest that it be considered a key target for future conservation efforts. Additionally, we recommend that this species continue to be listed as endangered in Colombia and not be modified in the CITES Appendix I.

Multi-decadal changes in structural complexity following mass coral mortality on a Caribbean reef

In recent decades, extensive mortality of reef-building corals throughout the Caribbean region has led to the erosion of reef frameworks and declines in biodiversity. Using field observations, structural models, and high-precision U–Th dating methods, we quantify changes in structural complexity in the major framework-building coral Orbicella annularis over a 20-year period at Long Caye (Belize). Despite extensive mortality following the mass coral bleaching event of 1998, the structural complexity of frameworks remained largely unchanged between 1998 (rugosity index, R, of 2.35±0.1) and 2018 (R of 2.29±0.1). Colony-scale structural complexity was maintained, as the rapid growth of surviving ramets (0.69±0.1 cm yr−1) offset the slower bioerosion of dead ramets (-0.11±0.16 cm yr−1). Despite the apparent stability of the structural complexity at colony scales, bioerosion of individual dead ramets over 2 decades led to declines in microhabitat complexity, with an overall reduction in the depth of microhabitats within frameworks. Altered microhabitat complexity appears to have negative effects on cryptic fauna, with the grazing urchin Echinometra viridis declining from 1.5±0.4 individuals m−2 in 1998 to 0.02± individuals m−2 in 2018. Changes in microhabitat complexity have the potential to alter ecological interactions that can impact recovery dynamics on coral reefs in ways that are undetectable using traditional rugosity metrics of structural complexity.

Synthesis, Characterization and Antimicrobial Activities of Mixed Ligand Complexes of Fe (II), Co(II), Ni(II) and Cu (II) Ions Derived from Imine of Benzidine and o-phenylenediammine

Binuclear metal complexes of the metal ions Fe (II), Co (II), Ni (II) and Cu (II) were synthesized by the reaction of these metal ions with the imine of benzidine (H2L) as a primary ligand and o-phenylenediammine (OPD) as a secondary ligand in a molar ratio of 2:2:1. The prepared complexes were characterized using CHN elemental analysis, FT-IR, UV-visible, molar conductivity, magnetic susceptibility and TGA-DTA thermogravimetric analysis. All the prepared complexes showed apparent stability and could be stored for months without any appreciable change. According to the results obtained by elemental and spectral analyses, a tetrahedral structure is suggested for all the prepared complexes, except for the copper complex which showed a square planar structure. The antimicrobial activities of these complexes were evaluated against Bacillus spp. (Gram-negative bacteria), Proteus spp. (Gram-positive bacteria) and Aspergillus niger (A. niger, a fungal species). The results showed that all the prepared complexes have no apparent effects on Bacillus spp. viability, whereas Proteus spp. and A. niger were affected significantly.