Examining Evolutionary Rate in Xiphosura

Horseshoe crabs, a group of aquatic chelicerate arthropods of the class Xiphosura, are strongly linked with the concept of “living fossils” – a term colloquially used to refer to clades that display a consistently low rate of morphological evolution through time. The concept of living fossils has been hotly debated, as it is considered to simplify or obscure millennia of evolutionary change. Recent methodological and computational advances in the paleobiological sciences have allowed for the investigation of these claims. Xiphosura are a model taxon for this type of investigative study because they exhibit a complex evolutionary history, despite their reputation as “living fossils”. Xiphosura first appear in the fossil record during the Ordovician and are represented today by four extant species. During these 480 million years of evolution, Xiphosura have displayed a remarkably stable body plan, most notably in Limulidae, the sole surviving clade from the Mesozoic onwards; however, there are also aberrant forms associated with the exploration of nonmarine niches. The presence of these forms in the fossil record indicates a more complex evolutionary history than is usually attributed to Xiphosura, including events of both rapid evolutionary change and stasis. A comprehensive study of evolutionary rate in horseshoe crabs through their fossil record has not yet been conducted. Thus, their status as a clade with consistently low rate of evolution has not been evaluated. An investigation of evolutionary rates in Xiphosura using discrete character data reveals heterogeneous rates of evolution; specifically, high rates of evolution cluster within Belinurina and Austrolimulidae – two clades that display heterochronic morphological trends and affinities for non-marine environments. Additionally, these high evolutionary rates occur after the transition to nonmarine habitats, indicating a driving environmental pull behind shifts to heterochronic morphologies. Conversely, the clades that show no concerted heterochronic trends – Limulidae and Paleolimulidae – produced varied high and low rates, with a tendency towards lower rates of discrete character evolution. Xiphosura also show variable rates of evolution through time, with higher rates corresponding to mass extinction events and radiations. Average evolutionary rate in Xiphosura has also decreased through time, though there is still variability present. Overall, horseshoe crabs show variable and dynamic evolutionary patterns through time, therefore indicating that they are not “living fossils.

Responses to the Crisis of Neoliberal Globalization: State Intervention in Palm Oil Production in Chiapas, Mexico

Article originally published in International Journal of Sociology of AgricultureEmploying the case study of the cultivation of African palms for the production of palm oil in Chiapas, Mexico, this article probes the theme of alternative patterns of development to neo-liberal globalization. In particular, it discusses the issue of the return to state intervention (neo-Fordism) as an instrument to promote socio-economic development. Chiapas has been the theatre of the Zapatista movement of 1994. As a result of that popular uprising and despite its overtly neo-liberal posture, the Mexican state intervened significantly in Chiapas. In this context, the monoculture of the African palm has been pursued as a strategy to address local poverty among farmers, generate alternative and renewable forms of energy and provide a scheme for socio-economic growth in the area. This article illustrates the contradictory results of this ‘interventionist’ developmental project and the consequences and resistance that it entailed. The analysis of this case reveals the problematic nature of nation-state led interventionist schemes in a context marked by the emerging crisis of the neo-liberal model. It also underscores the significance of local initiatives that are generated by the aspirations and abilities of local residents.Sociolog

An Overview of the Downdraft Rice Husk Gasifier Technology for Thermal and Power Applications

An overview of the downdraft rice husk gasifier (DDRHG) for thermal and power applications is herein presented. The different designs of the downdraft rice husk gasifier with reactor diameter ranging from 0.10 meter to 1.20 meter are discussed in detail. Smaller units of the DDRHG were found to have performed well in fixed bed. Larger units of the gasifier, on the other hand, are suited for moving-bed type making possible continuous operation without discharging and recharging the reactor. Present thermal applications of the gasifier includes: domestic cookstove, bakery oven, dryers, rotary kiln, steam boiler, and torrefyer. The DDRHG is also used to run surplus gasoline engines for driving water pump, micro-mill, and electric generator without any modification. The advantages and limitations of the gasifier as well as its environmental and socio-economic benefits over the use of conventional fossil-fueled systems are enumerated. At present, the investment cost for the gasifier ranges from PHP2,000 to 2,500.00 (USD 1 = PHP40.00) per kWt for thermal application and PHP20,000.00 to 30,000 per kWe for power generation. The cost of using the gasifier is much cheaper than that of the conventional fossil fuel and the investment can be recovered in a shorter period

Yeast biodiversity in vineyard environments is increased by human intervention

One hundred and five grape samples were collected during two consecutive years from 33 locations on seven oceanic islands of the Azores Archipelago. Grape samples were obtained from vineyards that were either abandoned or under regular cultivation involving common viticultural interventions, to evaluate the impact of regular human intervention on grape yeast biota diversity in vineyards. A total of 3150 yeast isolates were obtained and 23 yeast species were identified. The predominant species were Hanseniaspora uvarum, Pichia terricola, Starmerella bacillaris and Issatchenkia hanoiensis. The species Barnettozyma californica, Candida azymoides and Pichia cecembensis were reported in grapes or wine-associated environments for the first time. A higher biodiversity was found in active vineyards where regular human intervention takes place (Shannon index: 1.89 and 1.53 in the first and second years, respectively) when compared to the abandoned ones (Shannon index: 0.76 and 0.31). This finding goes against the assumptions that human intervention can destroy biodiversity and lead to homogeneity in the environment. Biodiversity indices were considerably lower in the year with the heaviest rainfall. This study is the first to report on the grape yeast communities from several abandoned vineyards that have undergone no human intervention.Joao Drumonde Neves is the recipient of a fellowship of the Azorean Government (M321/006/F/2008) and PROEMPREGO. This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI), and by national funds through FCT by the projects FCOMP-01-0124-008775, PTDC/AGR-ALI/103392/2008 and PTDC/AGR-ALI/121062/2010.info:eu-repo/semantics/publishedVersio

Association between Grape Yeast Communities and the Vineyard Ecosystems

The grape yeast biota from several wine-producing areas, with distinct soil types and grapevine training systems, was assessed on five islands of Azores Archipelago, and differences in yeast communities composition associated with the geographic origin of the grapes were explored. Fifty-seven grape samples belonging to the Vitis vinifera grapevine cultivars Verdelho dos Acores (Verdelho), Arinto da Terceira (Arinto) and Terrantez do Pico (Terrantez) were collected in two consecutive years and 40 spontaneous fermentations were achieved. A total of 1710 yeast isolates were obtained from freshly crushed grapes and 1200 from final stage of fermentations. Twenty-eight species were identified, Hanseniaspura uvarum, Pichia terricola and Metschnikowia pulcherrima being the three most representative species isolated. Candida carpophila was encountered for the first time as an inhabitant of grape or wine-associated environments. In both sampling years, a higher proportion of H. uvarum in fresh grapes from Verdelho cultivar was observed, in comparison with Arinto cultivar. Qualitatively significant differences were found among yeast communities from several locations on five islands of the Archipelago, particularly in locations with distinctive agro-ecological compositions. Our results are in agreement with the statement that grape-associated microbial biogeography is non-randomly associated with interactions of climate, soil, cultivar, and vine training systems in vineyard ecosystems. Our observations strongly support a possible linkage between grape yeast and wine typicality, reinforcing the statement that different viti-cultural terroirs harbor distinctive yeast biota, in particular in vineyards with very distinctive environmental conditions.Joao Drumonde Neves is the recipient of a fellowship of the Azorean Government (M321/006/F/2008) and PROEMPREGO. This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI), and by national funds through FCT by the projects FCOMP-01-0124-008775, PTDC/AGR-ALI/103392/2008 and PTDC/AGR-ALI/121062/2010.info:eu-repo/semantics/publishedVersio

Responses to the Crisis of Neo-liberal Globalization: State Intervention in Palm Oil Production in Chiapas, Mexico

Employing the case study of the cultivation of African palms for the production of palm oil in Chiapas, Mexico, this article probes the theme of alternative patterns of development to neo-liberal globalization. In particular, it discusses the issue of the return to state intervention (neo-Fordism) as an instrument to promote socio-economic development. Chiapas has been the theatre of the Zapatista movement of 1994. As a result of that popular uprising and despite its overtly neo-liberal posture, the Mexican state intervened significantly in Chiapas. In this context, the monoculture of the African palm has been pursued as a strategy to address local poverty among farmers, generate alternative and renewable forms of energy and provide a scheme for socio-economic growth in the area. This article illustrates the contradictory results of this ‘interventionist’ developmental project and the consequences and resistance that it entailed. The analysis of this case reveals the problematic nature of nation-state led interventionist schemes in a context marked by the emerging crisis of the neo-liberal model. It also underscores the significance of local initiatives that are generated by the aspirations and abilities of local residents