Responses of transplanted native tree species to invasive alien grass removals in an abandoned cattle pasture in the Lacandon region, Mexico

We tested the early performance of 16 native early-, mid-, and late-successional tree species in response to four intensities of grass removal in an abandoned cattle pasture dominated by the introduced, invasive African grass, Cynodon plectostachyus, within the Lacandon rainforest region, southeast Mexico. The increase in grass removals significantly improved the performance of many species, especially of early-and mid-successional species, while performance of late-successional species was relatively poor and did not differ significantly among treatments. Good site preparation and at least one additional grass removal four months after seedling transplant were found to be essential; additional grass removals led to improved significantly performance of saplings in most cases. In order to evaluate the potential of transplanting tree seedlings successfully in abandoned tropical pastures, we developed a "planting risk index", combining field performance measurements and plantation cost estimations. Our results showed a great potential for establishing restoration plantings with many early-and mid-successional species. Although planting risk of late-successional species was considered high, certain species showed some possibilities of acclimation after 18 months and should be considered in future plantation arrangements in view of their long-term contributions to biodiversity maintenance and also to human welfare through delivery of ecosystem services. Conducting a planting risk analysis can help avoid failure of restoration strategies involving simultaneous planting of early-, mid-, and late-successional tree species. This in turn will improve cost-effectiveness of initial interventions in large-scale, long-term restoration programs.

Testing the Performance of Fourteen Native Tropical Tree Species in Two Abandoned Pastures of the Lacandon Rainforest Region of Chiapas, Mexico

The rainforest of Mexico has been degraded and severely fragmented, and urgently require restoration. However, the practice of restoration has been limited by the lack of species-specific data on survival and growth responses to local environmental variation. This study explores the differential performance of 14 wet tropical early-, mid- or late-successional tree species that were grown in two abandoned pastures with contrasting land-use histories. After 18 months, seedling survival and growth of at least 7 of the 14 tree species studied were significantly higher in the site with a much longer history of land use (site 2). Saplings of the three early-successional species showed exceptional growth rates. However, differences in performance were noted in relation to the differential soil properties between the experimental sites. Mid-successional species generally showed slow growth rates but high seedling survival, whereas late-successional species exhibited poor seedling survival at both the study sites. Stepwise linear regressions revealed that the species integrated response index combining survivorship and growth measurements, was influenced mostly by differences in soil pH between the two abandoned pastures. Our results suggest that local environmental variation among abandoned pastures of contrasting land-use histories influences sapling survival and growth. Furthermore, the similarity of responses among species with the same successional status allowed us to make some preliminary site and species-specific silvicultural recommendations. Future field experiments should extend the number of species and the range of environmental conditions to identify site generalists or more narrowly adapted species, that we would call sensitive.

Population structure and sexual maturity of the calico box crab Hepatus epheliticus Linnaeus (Brachyura, Hepatidae) from Yucatan Peninsula, Mexico

The calico box crab Hepatus epheliticus is an abundant species from shallow and continental shelf waters of the Atlantic coast of USA and Mexico. Information about population structure and sexual maturity is absent, even though this crab is caught to be used as bait for the octopus fishery in the Campeche Bank, Mexico. In order to achieve such information, a total of 768 individuals were collected from January to March 2010 through baited traps installed in the Yucatan Peninsula, Mexico. Our results showed that sex ratio is biased towards more males than females (1:0.55), contradicting to that reported in other brachyuran crabs. The absence of ovigerous females suggests that they did not enter into the traps during embryogenesis. Males reached a larger maximum size than females (64.0 +/- 6.15 and 58.4 +/- 5.60 mm carapace width, respectively). The general scheme of growth being positive allometric throughout ontogeny of both sexes. Males presented a transition phase from juveniles to adult corresponding to the puberty moult. The estimation of the onset of functional sexual maturity revealed a steady situation for the population, with 21.5 and 13.8% of males and females, respectively, morphologically immature at the time of catch. This study constitutes the first report on population structure and sexual maturity in a population of the calico box crab H. epheliticus.

Tentativa de balanço: entrevista com Iumna Maria Simon

Narrando a sua formação intelectual, Iumna Maria Simon analisa a situação da crítica literária na universidade e fora dela, a poesia contemporânea e as condições da leitura da obra literária hoje. A entrevista expõe o modo como desenvolveu sua compreensão da literatura brasileira mais recente e como organiza seu foco crítico e suas referências teóricas, enquanto professora e crítica.

Um balanço de parte da teoria dos sistemas intencionais de Dennett

Dennett (1981/1987b) caracteriza sua abordagem do funcionamento dos termos intencionais (aqueles para as assim chamadas atitudes proposicionais) como um "behaviorismo lógico holista", ou versão holista de delineamentos conceituais traçados por Ryle (1949). Este artigo avalia algumas de suas possíveis contribuições e desvantagens para tais delineamentos, e algumas consequências para sua proposta de utilização destes termos em psicologia. Argumenta-se que a abordagem não se mostra mais plausível do que a de seu predecessor, caso a dimensão mentalista que lhe acrescenta seja equivocada, e que de fato este é o caso. Disso resulta que suas contribuições e proposta correlata devem ser entendidas com independência daquilo que tal dimensão implica. Uma alternativa não-mentalista, baseada no modelo selecionista de Skinner, para uma eventual adoção dos termos intencionais em psicologia, é brevemente discutida.

Long-term variability and effects on larval fish distribution of the Gulf of Mexico Loop Current and Rings

Programa de doctorado: Oceanografía

Ni una más. International cooperation against gender-based discrimination: the femicide case in Ciudad Juárez, Chihuahua, Mexico

The femicide in Ciudad Juárez is a story made of extreme violence against women for different reasons, by different actors, under different circumstances, and following different behavioural patterns. All within a gender discrimination frame based on the idea that women are inferior, interchangeable and disposable according to the patriarchal hierarchy still present in Mexico, but strongly reinforced by a sort of conspiracy of silence provoked either by the high impunity rate, the governmental incompetence to solve the crimes, or the general indifference of the population. It is the story of hundreds of kidnapped, raped, in many cases tortured, and murdered young women in the border between Mexico and the United States. The murders first came into light in 1993 and up to now young women continue to “disappear” without any hope of bringing the perpetrators to justice, stopping impunity, convicting the assassins, and bringing justice to the families of the deceased girls and women. The main questions about femicide in Ciudad Juárez seem to be: why were they brutally assassinated?, why most of the crimes have not been solved yet?, why and how is Ciudad Juárez different from other border cities with the same characteristics?, which powers are behind those crimes in a city that implies mainly women as its labor force, and which has the lowest unemployment rate in the whole country? But there are also many other questions dealing more with the context, the Juarences’ lifestyles, the eventual hidden powers behind the crimes, the possible murderers’ reasons, the response of the local civil society, or the international community actions to fight against femicide there, among many other things, that are still waiting for an answer and that this paper will ‘narrate’ in order to provide a holistic panorama for the readers. But above all there is the need to remember that every single woman or girl assassinated there had a name, an identity, a family, a story to be told time after time and as many times as necessary, in order to avoid accepting these crimes just as statistics, as cold numbers that might make us forget the human tragedy that has been flagellating the city since 1993. We must remember as well that their deaths express gender oppression, the inequality of the relations between what is male and what is female, a manifestation of domination, terror, social extermination, patriarchal hegemony, social class and impunity. The city is the perfect mirror where all the contradictions of globalization get reflected. It is there where all the globalization evils are present and survive by sucking their women’s blood. It is a city where some concepts such as gender, migration and power are closely related with a negative connotation.

Decompression during Late Proterozoic Al2SiO5 Triple-Point Metamorphism at Cerro Colorado, New Mexico

An outstanding problem in understanding the late Proterozoic tectonic assembly of the southwest is identifying the tectonic setting associated with regional metamorphism at 1.4 Ga. Both isobaric heating and cooling, and counter-clockwise looping PT paths are proposed for this time. We present a study of the Proterozoic metamorphic and deformation history of the Cerro Colorado area, southern Tusas Mountains, New Mexico, which shows that the metamorphism in this area records near-isothermal decompression from 6 to 4 kbar at ca. 1.4 Ga. We do not see evidence for isobaric heating at this time. Decompression from peak pressures is recorded by the reaction Ms + Grt = St + Bt, with a negative slope in PT space; the reaction Ms + Grt = Sil + Bt, which is nearly horizontal in PT space; and partial to total pseudomorphing of kyanite by sillimanite during the main phase of deformation. The clearest reaction texture indicating decompression near peak metamorphic temperature is the replacement of garnet by clots of sillimanite, which are surrounded by halos of biotite. The sillimanite clots, most without relict garnet in the cores and with highly variable aspect ratios, are aligned. They define a lineation that formed with the dominant foliation. An inverted metamorphic gradient is locally defined by sillimanite-garnet schists (625 degrees C) structurally above staurolite-garnet schists (550 degrees C) and implies ductile thrusting during the main phase of deformation. The exhumation that led to the recorded decompression was likely in response to crustal thickening due to ductile thrusting and subsequent denudation.

Detrital Zircon Evidence for Non-Laurentian Provenance, Mesoproterozoic (ca. 1490-1450 Ma) Deposition and Orogenesis in a Reconstructed Orogenic Belt, Northern New Mexico, USA: Defining the Picuris Orogeny

Detrital zircon and igneous zircon U-Pb ages are reported from Proterozoic metamorphic rocks in northern New Mexico. These data give new insight into the provenance and depositional age of a >3-km-thick metasedimentary succession and help resolve the timing of orogenesis within an area of overlapping accretionary orogens and thermal events related to the Proterozoic tectonic evolution of southwest Laurentia. Three samples from the Paleoproterozoic Vadito Group yield narrow, unimodal detrital zircon age spectra with peak ages near 1710 Ma. Igneous rocks that intrude the Vadito Group include the Cerro Alto metadacite, the Picuris Pueblo granite, and the Penasco quartz monzonite and yield crystallization ages of 1710 +/- 10 Ma, 1699 +/- 3 Ma, and 1450 +/- 10 Ma, respectively. Within the overlying Hondo Group, a metamorphosed tuff layer from the Pilar Formation yields an age of 1488 +/- 6 Ma and represents the first direct depositional age constraint on any part of the Proterozoic metasedimentary succession in northern New Mexico. Detrital zircon from the overlying Piedra Lumbre Formation yield a minimum age peak of 1475 Ma, and similar to 60 grains (similar to 25%) yield ages between 1500 Ma and 1600 Ma, possibly representing non-Laurentian detritus originating from Australia and/or Antarctica. Detrital zircons from the basal metaconglomerate and the middle quartzite member of the Marquenas Formation yield minimum age peaks of 1472 Ma and 1471 Ma, consistent with earlier results. We interpret the onset of ca. 1490-1450 Ma deposition followed by tectonic burial, regional Al2SiO5 triple-point metamorphism, and ductile deformation at depths of 12-18 km to reflect a Mesoproterozoic contractional orogenic event, possibly related to the final suturing of the Mazatzal crustal province to the southern margin of Laurentia. We propose to call this event the Picuris orogeny.