A previously published conceptual model of the life history of the red crab Pleuroncodes planipes (Galathei- dae) (Stimpson, 1860) reports that the center of distribution of this micronektonic crustacean is located at Bahía Magdalena, on the southwest coast of Baja California (25 to 24° 20' N). During spring, the highest abundance of mature females is found nearshore with abundance peaks of larval stages dur- ing February and March. Larval drift offshore is associated with a strong Ekman transport system, and the virtual disap- pearance of the adult pelagic and benthic population from the neritic region at Bahía Magdalena in late summer and autumn can be explained by an inshore-offshore migration. However, huge benthic-pelagic concentrations of this crus- tacean occur nearshore during autumn at Punta Eugenia (27 to 29° N). Circadian cycles of the spatial distribution of these aggregations were recorded with a single beam echosounder Simrad EY-200 (200 kHz) along Baja California during Octo- ber 1994, March, June, and October 1995, and March and June 1996. Data obtained from Isaacs-Kidd midwater net trawls during October 1994 along Baja California were used to identify the red crab aggregations using hydroacoustics. The target strength of the red crab ranged between -50 and -54 dB. The largest aggregations were found in Bahía Mag- dalena during summer (June 1995 and 1996; 24 to 25° N) and nearshore at Punta Eugenia (27 to 28° N) during autumn and spring (March 1995 and 1996, October 1994 and 1995). These observations suggest that the conceptual model of inshore- offshore adult population migration is valid for Bahía Mag- dalena, but apparently not for Punta Eugenia at least during autumn. At Punta Eugenia an abrupt change in the orienta- tion of the shoreline enhances upwelling events and promotes semipermanent eddies, thus supporting the inshore residence of this adaptive omnivorous-detritivorous crustacean.

The sustainability of the traditional maize agroecosystem in Ahuazotepec, Mexico, was evaluated using a cluster analysis for the typification of the producers and the Framework for Assessing the Sustainability of Natural Resource Management Systems approach for the sustainability assessment. Results revealed three groups within the agroecosystem: low-traditional, medium-traditional, and transition. Clusters differed in grain yield, income, age, education, organization, production practices, and complementary economic activities. Sustainability evaluation showed that productivity was the most influential attribute as the grain yield determined how efficiently the production resources are utilized, which in turn influences some environmental and social attributes. Information obtained allows the generation of a baseline and specific suggestions for improving sustainability of the clusters.

Agro-industrial activities such as livestock production and maize processing generate large amounts of waste that can pollute the environment if not treated. To reduce the environmental impact of such wastes, the use of nejayote and ovine manure as fertilizers in maize production was evaluated in terms of yield (GY), energy efficiency (EE) and benefit-to-cost ratio (BCR), during 2015 and 2016. A factorial experiment was designed combining nejayote (0, 75 and 150 m³ ha⁻¹) with manure (0, 25 and 50 Mg ha⁻¹), those treatments were compared with a chemical fertilizer treatment (120N–60P–30K); treatments were done in three replicates. Nejayote-manure fertilizers were characterized physical and chemically. Inputs and outputs used/obtained during the production cycle were registered in terms of their energy equivalents and economic value. At the end of each cycle GY, EE and BCR were calculated. Results showed that nejayote-manure mixtures were 19% more energy efficient and produced a yield 12% greater than chemical fertilization (P=0.001), thus generating a BCR of 6.3 (P=0.023). Organic fertilizers were useful as waste treatments and produced greater benefits than chemical fertilizers. Additionally, the water recovered from nejayote was enough to provide a 7.5 or 15 mm of gross irrigation during the crop cycle.

The aim of this research was to evaluate the effects of UV-C light on lentil ( Lens culinaris ) and its conditioning by Spirulina . The main findings were: (i) Lentil brightness presented a significant slight variation (9%) when compared to the control (T 0 ) and UV-C (T 10 = 10 min) irradiated...