Time filter

Source Type

Espinoza T.E.B.,National University San Antonio Abad del Cusco
Novon | Year: 2014

Two new species were found during a taxonomic revision of Passiflora subg. Decaloba (DC.) Rchb. (Passifloraceae). Both new species are described and placed in the P. lobbii Mast. species group. Passiflora joergenseniana T. Boza is from La Paz, Bolivia, and P. praemorsa T. Boza is from Cusco, Peru, and is also distributed in La Paz, Bolivia. Conservation assessments and geographic distributions for each species are provided, and morphological variability within each species is discussed. Similarities to and differences among these new species and putative close relatives are also examined.

Ferrer I.,University of Barcelona | Garfi M.,University of Barcelona | Uggetti E.,University of Barcelona | Ferrer-Marti L.,University of Barcelona | And 2 more authors.
Biomass and Bioenergy | Year: 2011

Low-cost tubular digesters originally developed in tropical regions have been adapted to the extreme weather conditions of the Andean Plateau (3000-4000 m.a.s.l.). The aim of this study was to characterise biogas production in household digesters located at high altitude, operating under psychrophilic conditions. To this end, two pilot digesters were monitored and field campaigns were carried out in two representative digesters of rural communities. Digesters' useful volume ranged between 2.4 and 7.5 m 3, and hydraulic residence time (HRT) between 60 and 90 days. The temperature inside the digester's greenhouse ranged between 20 and 25 °C. Treating cow manure, a specific biogas production around 0.35 m 3 kg VS -1 was obtained, with some 65% CH 4 in biogas. In order to fulfil daily requirements for cooking and lighting, biogas production should be enhanced without increasing implementation costs as not to impede the expansion of this technology at household scale. In this sense, HRT below 60 days and OLR above 1 kg VS m -3 day -1 should be investigated to decrease digesters' volume (i.e. costs) and increase biogas production rate. The adaptation of conventional gas burners to biogas characteristics can also contribute in improving the efficiency of the system. © 2011 Elsevier Ltd.

Zimmermann M.,James Cook University | Zimmermann M.,University of Edinburgh | Meir P.,University of Edinburgh | Bird M.I.,James Cook University | And 2 more authors.
Global Biogeochemical Cycles | Year: 2010

To simulate the effect of temperature on soil respiration rates, we translocated soil cores among four sites (3030, 1500, 1000, and 200 m asl) along an altitudinal tropical forest gradient in the Peruvian Andes, traversing a difference in mean annual temperature of 13.9C. Rates of total (Rs) and heterotrophic (Rsh) respiration were measured twice a month from April 2007 to March 2009 and additionally for full 24 h periods. The diurnal range in Rs increased with altitude; this variation was mainly root and litter derived, whereas Rsh varied only slightly over full 24 h periods. Although mean annual daytime Rs rates were not significantly different among the four sites (4.45-4.05 mol CO2 m-2 s-1), the annual amount of respired C decreased with increasing altitude from 1639 g C m-2 yr-1 at 200 m asl to 1064 g C m-2 yr-1 at 3030 m asl. The contribution of Rsh to Rs was not correlated with elevation and ranged from 25% to 60%. The temperature dependence of Rs was lower at the midelevation sites (Q10 of 2.07 and 2.94 at 1500 and 1000 m asl, respectively) than at the highest and lowest sites of the gradient (Q10 of 4.33 and 6.92 at 3030 and 200 m asl, respectively). The temperature sensitivity of R sh was higher for the sites at 3030 and 200 m asl and increased with time, i.e., with the loss of the most labile C pools. © 2010 by the American Geophysical Union.

Salazar H.,University of Texas Medical Branch | Swanson J.,University of Texas Medical Branch | Mozo K.,National University San Antonio Abad del Cusco | Clinton White Jr. A.,University of Texas Medical Branch | Cabada M.M.,University of Texas Medical Branch
Journal of Travel Medicine | Year: 2012

Background Increasing numbers of travelers are visiting high altitude locations in the Andes. The epidemiology of acute mountain sickness (AMS) among tourists to high altitude in South America is not well understood. Methods A cross-sectional study to evaluate the epidemiology, pre-travel preparation, and impact of AMS among travelers to Cusco, Peru (3,400 m) was performed at Cusco's International Airport during June 2010. Foreign travelers, 18 years or older, staying 15 days or less, departing Cusco were invited to participate. Demographic, itinerary, and behavioral data were collected. The Lake Louise Clinical score (LLCS) was used to assess AMS symptoms. Results In total, 991 travelers participated, median age 32 years (interquartile range 25-49), 55.5% female, 86.7% tourists, mostly from the United States (48.2%) and England (8.1%). Most (76.7%) flew from sea level to Cusco and 30.5% visited high altitude in the previous 2 months. Only 29.1% received AMS advice from a physician, 19% recalled advice on acetazolamide. Coca leaf products (62.8%) were used more often than acetazolamide (16.6%) for prevention. AMS was reported by 48.5% and 17.1% had severe AMS. One in five travelers with AMS altered their travel plans. Travelers older than 60 years, with recent high altitude exposure, who visited lower cities in their itinerary, or used acetazolamide were less likely to have AMS. Using coca leaf products was associated with increased AMS frequency. Conclusions AMS was common and adversely impacted plans of one in five travelers. Acetazolamide was associated with decreased AMS but was prescribed infrequently. Other preventive measures were not associated with a decrease in AMS in this population. Pre-travel preparation was suboptimal. © 2012 International Society of Travel Medicine.

van de Weg M.J.,University of Edinburgh | van de Weg M.J.,The Ecosystem Center | Meir P.,University of Edinburgh | Grace J.,University of Edinburgh | Ramos G.D.,National University San Antonio Abad del Cusco
Oecologia | Year: 2012

Few data are available describing the photosynthetic parameters of the leaves of tropical montane cloud forests (TMCF). Here, we present a study of photosynthetic leaf traits (V cmax and J max), foliar dark respiration (R d), foliar nitrogen (N) and phosphorus (P), and leaf mass per area (LMA) throughout the canopy for five different TMCF species at 3025 m a. s. l. in Andean Peru. All leaf traits showed a significant relationship with canopy height when expressed on an area basis, and V cmax-area and J max-area almost halved when descending through the TMCF canopy. When corrected to a common temperature, average V cmax and J max on a leaf area basis were similar to lowland tropical values, but lower when expressed on a mass basis, because of the higher TMCF LMA values. By contrast, R d on an area basis was higher than found in tropical lowland forests at a common temperature, and similar to lowland forests on a mass basis. The TMCF J max-V cmax relationship was steeper than in other tropical biomes, and we propose that this can be explained by either the light conditions or the relatively low VPD in the studied TMCF. Furthermore, V cmax had a significant-though relatively weak and shallow-relationship with N on an area basis, but not with P, which is consistent with the general hypothesis that TMCFs are N rather than P limited. Finally, the observed V cmax-N relationship (i.e., maximum photosynthetic nitrogen use efficiency) was distinctly different from those in tropical and temperate regions, probably because the TMCF leaves compensate for reduced Rubisco activity in cool environments. © 2011 Springer-Verlag.

Discover hidden collaborations