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• The collection of orchid pseudobulbs is a conservation problem. • Extraction of pseudobulbs diminishes orchid growth and flowering. • After two years, plants subject to extraction didn't recover the lost biomass. • The collected plant sections can be used to restore orchid populations. • Pseudobulbs extraction must be avoided, and fallow periods allow plant recovery. The illegal collection of wild orchid pseudobulbs is a conservation problem, but little is known about this practice's consequences in orchid individuals. In some regions of Mexico, the latest two pseudobulbs of Laelia autumnalis plants are collected and traded, including the inflorescence. We: 1.- determined the nutrient content of pseudobulbs/leaves, 2.- tested the effect of pseudobulbs harvest in the survival, growth, flowering, and 3.- explored if the removed sections can be used to restore populations. In three L. autumnalis populations, we selected five small (one inflorescence), five medium-sized (one inflorescence), and five big (two inflorescences) plants. In each plant, we marked 8–10 pseudobulb along a growth chain (two in big plants); pseudobulb/leaves were measured (wide, height, length), and their biomass was estimated. We removed the latest two (in large plants, the harvest was done in one chain, and the other was a control). The removed pseudobulbs were tied in the same tree. Nutrient content was higher in leaves. No plant died because of the pseudobulb's harvest; >55% produced new pseudobulbs yearly. Among the big plants, pseudobulb production was constant (87%) in the control chains but not in the chains subject to harvest; in these, inflorescence production was lower. Four removed sections died, and <40% developed new pseudobulbs yearly. The harvest of the most recent two pseudobulbs diminish the growth and reproduction of L. autumnalis , and after two years, the plants did not recover the lost biomass. Removed sections can be used to restore populations, but these must be assisted with nutrients and watering. [ABSTRACT FROM AUTHOR]

Sand crabs are one of the most important and abundant invertebrates in the sandy beaches ecosystem of the Pacific sea. After death, this crustacean generates large quantities of solid waste in the form of body carapace (exoskeleton), which has caused pollution and affecting human life quality. The carapace is primarily composed of chitin and proteins. Therefore, this bio-waste could be employed as a potential source of chitosan, providing health benefit to human. Thus, in this work, samples with different deacetylation percentage of chitosan were obtained. Separate treatments were applied to the carapace and the ends. The microscopic particles are flake-like structures with size range of 110 – 220 µm and uniformly distributed porosity was found in the end samples. An orthorhombic crystal structure (crystallinity of 30%) was observed, similar to the sample reported in literature. Ash, humidity and insoluble matter percentage confirmed the quality of chitosan for potential biomedical applications. [Display omitted] • Obtention of chitosan with various deacetylation percentages from sand crab carapace. • Higher NH% results in small size flake-like particles, and vice versa. • A set of pores uniformly distributed on the surface of end samples. • An orthorhombic structure with 30% crystallinity was found, similar shrimp chitosan. [ABSTRACT FROM AUTHOR]

• Although extraction is recognized as a threat for orchids, its effects are unknown. • Extraction increases the abundance of old plants but diminishes that of the young. • Plant sections extraction diminishes the biomass of the plants and their flowering. • Fallow periods are required in populations under extraction. Chronic anthropogenic disturbance caused by the extraction of plant sections or entire individuals from wild populations can modify the population structure of the plants. Population structure, plant biomass capital and reproductive probability were compared in five Laelia autumnalis populations under different extraction intensities. For each plant, the number of pseudobulbs was counted and the biomass of each pseudobulb estimated and its live/dead status recorded along with the presence of inflorescence remnants. The live biomass of each plant was related to its total number of pseudobulbs. In populations under greater levels of extraction, the plants accumulate less biomass as they become larger. In populations under lower extraction, there was a greater abundance of small plants (1–9 and 10–18 pseudobulbs). In contrast, populations under higher extraction presented a structure with a greater abundance of large individuals (>19 pseudobulbs). In all populations, the frequency of the remains of inflorescences increases with plant size. In contrast, the development of inflorescences in the study season decreased as the intensity of extraction increased. In conclusion, extraction of Laelia autumnalis plants causes them to accumulate less biomass and become less likely to develop inflorescences as they age, and ultimately modifies their population structure toward an abundance of large, old plants. [ABSTRACT FROM AUTHOR]

The September 19, 2017 earthquake (M w = 7.1) was the most damaging earthquake that stroke Mexico City since the September 19, 1985 earthquake. However, taking aside the southeast region of Mexico City, where very strong ground motions were recorded, in the central region for the city, spectral accelerations were more than well-covered by the design spectra of Mexico City building codes since 1987. In this paper, and based upon a detailed inventory of 2458 damaged structures, the observed structural damage is discussed from several angles, in particular, the relationships of observed damage with: a) use for the structure, b) structural systems, c) number of stories, d) plan geometries and conditions of structural irregularity, e) conditions which increases the seismic vulnerability, and f) seismic codes, spectral accelerations and global ductility demands assessed from recorded ground motions. Although it can be concluded that total number of structural collapses and severe damage was smaller for buildings designed according to the collapse-prevention design philosophy in Mexico City (802) in comparison to former older codes (967), this total number is not acceptable from an engineering, social and economical viewpoints. In the opinion of the authors, engineers should start thinking seriously on moving towards resilient-based seismic design strategies to reduce such large extent of damage in modern, newly constructed buildings in very active seismic zones such as Mexico City. [ABSTRACT FROM AUTHOR]