Carlos Enrique Álvarez

Risk factors of treatment failure in community acquired pneumonia: implications for disease outcome

Background: An inadequate response to initial empirical treatment of community acquired pneumonia (CAP) represents a challenge for clinicians and requires early identification and intervention. A study was undertaken to quantify the incidence of failure of empirical treatment in CAP, to identify risk factors for treatment failure, and to determine the implications of treatment failure on the outcome. Methods: A prospective multicentre cohort study was performed in 1424 hospitalised patients from 15 hospitals. Early treatment failure (<72 hours), late treatment failure, and in-hospital mortality were recorded. Results: Treatment failure occurred in 215 patients (15.1%): 134 early failure (62.3%) and 81 late failure (37.7%). The causes were infectious in 86 patients (40%), non-infectious in 34 (15.8%), and undetermined in 95. The independent risk factors associated with treatment failure in a stepwise logistic regression analysis were liver disease, pneumonia risk class, leucopenia, multilobar CAP, pleural effusion, and radiological signs of cavitation. Independent factors associated with a lower risk of treatment failure were influenza vaccination, initial treatment with fluoroquinolones, and chronic obstructive pulmonary disease (COPD). Mortality was significantly higher in patients with treatment failure (25% v 2%). Failure of empirical treatment increased the mortality of CAP 11-fold after adjustment for risk class. Conclusions: Although these findings need to be confirmed by randomised studies, they suggest possible interventions to decrease mortality due to CAP.

Apparent availability of nitrogen in composted municipal refuse

The use of composted municipal refuse on agricultural land requires prior knowledge of the interactions among compost, soil, and plants. Research into the availability of N in highly matured municipal refuse compost is particularly important considering the current concern about groundwater contamination by NOinf3sup--N. A greenhouse pot bioassay was conducted to determine the percentage of short-term apparent bioavailable N of a highly matured refuse compost and its relative efficiency in supplying inorganic N to the soil-plant system in comparison with NH4NO3. Municipal refuse (after 165 days of composting) was applied at rates equivalent to 10, 20, 30, 40, and 50 t ha-1 to a ferrallitic soil from Tenerife Island (Andeptic Paludult). NH4NO3 was applied at rates equivalent to the total N content of the compost treatments. Perennial ryegrass (Lolium perenne L.) was grown in 3-kg pots and the tops were harvested at regular intervals after seedling emergence. The compost increased dry matter yield, soil mineral N, and plant N uptake proportional to the applied rate. These increases were significantly higher than the control at an application rate of 20 t ha-1. After 6 months the apparent bioavailable N ranged from 16 to 21%. The relative efficiency was 43% after 30 days. This suggests that large inputs of inorganic N into soil can be obtained with high rates of this kind of compost, with a potential for NOinf3sup--N contamination. However, applied at moderate rates in our bioassay (<50 t ha-1), compost showed a low N-supplying capacity to ryegrass, i.e. a small fraction of the mineralized compost N was used by plants in the course of time. This was ascribed to a partial biological immobilization. This pattern of N availability in highly matured municipal refuse compost, positive net mineralization but partial immobilization, is similar to the pattern of N availability in biologically active soils and is therefore extremely interesting for the conservation of N in agro-ecosystems.

Pineapples Cultivated by Conventional and Organic Methods in a Soil from a Banana Plantation. A Comparative Study of Soil Fertility, Plant Nutrition and Yields

ABSTRACT A comparative study on conventional and organically grown pineapples cultivated in a soil from a banana plantation has been carried out in the Canary Islands. Garden waste compost was used as fertilizer in the organic treatment and current NPK fertilization in the conventional one. Soil pH, and available Ca and Mg were higher with the compost. “D” leaf N, K, Ca and Mg levels of plants from the conventional treatment exceeded those from the organic one, but only N seemed to influence yields. Foliar Cu and Zn were higher in plants from the compost treatment, but apparently this did not affect pineapple production. Fruits from both treatments had similar size and total weight, and free acids and sugar contents. The weight without crown of the fruits from the conventional treatment was significantly higher.

Effect of vanadium on lettuce growth, cationic nutrition, and yield

Abstract Lettuce plants (Lactuca sativa L.) cv. ‘grandes lagos’ were cultivated in nutrient solutions containing 0 (control), 0.1, 0.2, 0.5 and 1 mg/kg of vanadium. Root and leaf growth (expressed as fresh and dry weights) was inhibited by doses 0.2 to 1 mg/kg V. Yields decreased with increasing rates of vanadium. Toxicity symptoms in the roots consisted of color darkening, club shape of the main roots, reduction of secondary root number and length, and necrosis. Leaves from plants treated with 0.5 and 1.0 mg/kg V also showed turgidity loss. Vanadium accumulated in the roots and was poorly translocated to the leaves. All the treatments significantly increased vanadium root levels, but it augmented in the leaves only at the higher doses. Vanadium affected positively foliar Ca and Fe concentrations, but it depleted ? and Mg levels of the roots. 0.1 and 0.5 mg/kg vanadium in the nutrient solution decreased Mn in the roots, whereas the highest dose raised it.

Micronutrients in soils and plants from organic farms of Tenerife (Canary Islands)

ABSTRACT Soil and plant samples were taken from tropical fruit tree plantations, temperate fruit tree orchards and vegetable gardens grown using organic agricultural methods in Tenerife. Micronutrients Cu, Fe, Mn, and Zn were determined. The micronutrient content of most soils was found to fall within the normal range reported in the literature. Mn was present at low levels in the foliage of many plants, and a negative correlation between foliar Mn and soil organic matter content was observed in avocado and banana plantations. Consequently, maximum levels of soil organic matter content are established for avocado and banana. Cu, Fe, and Zn were also deficient in leaves of some plants.

Study of Soil Fertility and Plant Nutrition of Proteas Cultivated under Subtropical Conditions

Abstract: A study of soil physicochemical characteristics and mineral nutrition of four cultivars of Leucospermum cordifolium (‘Scarlett Ribbon,’ ‘High Gold,’ ‘Veldifre,’ ‘Sunrise’) and Leucospermum patersonii species was carried out along 2 years in commercial protea plantations, distributed throughout a subtropical region (La Palma Island, Canarian Archipelago). Soils presented a slightly acid pH range, whereas organic matter showed suitable values. Generally, available soil phosphorus (P) contents were less than 25 mg kg−1, with high available potassium (K) and calcium (Ca) levels, though the ratio of Ca of the sum of available cations was usually appropriate. Despite the high electrical conductivity (EC) levels (4.31–8.87 dS m−1) determined in some soils, no salinity symptoms were ever detected. Distribution and behavior of foliar nutrients nitrogen (N), P, K, Ca, magnesium (Mg), and sodium (Na) along time showed that nutritional needs varied in some cases among cultivars and species. L. patersonii presented the least N concentration, whereas ‘High Gold’ and ‘Veldfire’ had the greatest levels. Data denoted that P requirements were larger in younger plants, during the recovery after pruning, and while new buds developed. ‘Sunrise’ cultivar stood out for its large foliar levels of P, whereas ‘Scarlett Ribbon’ and ‘Veldfire’ had the least K contents. As a general pattern, K decreased in winter samplings. L. patersonii species and the cultivar ‘Sunrise’ exhibited the highest Ca values, and the same was true for Mg only in the species. A special need for Na appeared in all the cultivars and species studied. L. patersonii and the cultivar ‘Sunrise’ showed the greatest Na levels. A general stabilization of nutrient concentrations was observed in the fourth, fifth, and/or sixth samplings, so that November is recommended for taking samples for current foliar analysis. In this context, foliar ranges for the studied nutrients are suggested.

Effect of Compost, Farmyard Manure and/or Chemical Fertilizers on Potato Yield and Tuber Nutrient Content

ABSTRACT Potatoes (Solanum tuberosum L.) cv. Cara were cultivated over two years in an experimental plot at the University of La Laguna, Tenerife, Spain. Treatments consisted of fertilizing with single supply or binary combinations of commercial sheep manure compost, farmyard manure, ammonium nitrate and multicote (17-17-10 NPK coated fertilizer). A control without fertilizers was included to give ten treatments with four replications each, following a randomized blocks statistical design. Fertilizer rates were determined to supply 168 kg of N ha−1, in accordance with normal rates of N used by farmers. Each fertilizer of binary combinations supplied 50% of N. A rotation with lupin (Lupin us albus) preceded potato plantation. At flowering, lupin was cut and left on the soil as green manure. Potatoes were sown one month after cutting lupin. In both years of the assay, soil samples were taken twice from each treatment, the first sampling after cutting lupin, and the second 3 months after potato planting. All the measured soil parameters (pH, organic matter, total N, and available P, K, Ca and Mg) were within the ranges suited for potato development. Treatments did not affect these ranges. Potato yields were similar in all the treatments during the first year of cultivation, although in the second year potatoes that received ammonium nitrate, multicote, compost plus multicote or farmyard manure plus multicote gave significantly higher yields than those subjected to the other treatments. Control potatoes were the least productive in 1997. No clear behaviour of nutrient concentrations in tubers (N, P, K, Ca, Mg, Cu, Fe, Mn and Zn) was detected in relation to treatments. On the other hand, no correlations were observed among the studied parameters of the soils and/or the tubers.

Effect of fly ash from a fuel oil power station on heavy metal content of wild plants at Tenerife island, the Canarian archipelago, Spain

Abstract Heavy metal analysis have been carried out in wild plants around a Power Station located at the southeastern area of Tenerife Island (Canary Islands, Spain). The concentrations of Fe, Ni, and V in the leaves and terminal stems of three wild plants (Euphorbia obtusifolia, Kleinia neriifolia, and Plocama pendula) which were collected during the spring of 1988 are reported from four different allotments. These sampling sites were located at distances of 0.4, 1, 1,25, and 34 km from the Electric Generating Facility, and at elevations of 60, 120, 180 and 60 m, respectively. Results show a potential contamination of vanadium in E. obtusifolia and P. pendula plants located close to the Power Station, probably due to dry deposition on fly ash in the surrounding area. The levels of iron and nickel concentrations in the same type of plants did not show any geographical relationship with respect to the location of the Power Station.

Nutrient Removal, Fertilization Needs and Yields of Protea Plants Cultivated in Subtropical Conditions

ABSTRACT A study of nutrient removal was carried out in commercial protea plantations of each of the cultivars ‘Scarlett Ribbon,’ ‘High Gold,’ ‘Veldfire,’ and ‘Sunrise’ of Leucospermum cordifolium, and of the species L. patersonii,located in a subtropical region (La Palma, Canarian Archipelago). Flowering stems of optimal commercial quality were taken from each of the mentioned cultivars and species, once a year (2003 and 2004) at harvest time (January to April), and the different organs were analyzed separately. Flowering stems of the cultivars ‘High Gold’ and ‘Veldfire’ presented the highest contents of most studied nutrients, whereas the opposite was observed in ‘Scarlett Ribbon’ and L. patersonii. Mean yields of flowering stems varied very much among cultivars, and the highest ones were those of ‘High Gold’ and ‘Scarlett Ribbon’. The cultivar ‘High Gold’ removed the highest quantities of studied nutrients, and the contrary was observed in L. patersonii for most of them. Suitable rates of nitrogen (N): phosphorus (P): potassium (K) fertilizers for nutrient restitution purposes were 1:0.08:0.40 for ‘Scarlett Ribbon,’ 1:0.08:0.66 for ‘High Gold,’ 1:0.08:0.38 for ‘Veldfire,’ 1:0.09:0.75 for L. patersonii;and 1:0.18:1.11 for ‘Sunrise’.

INFLUENCE OF CLAY SOIL ON TWO PROTEA CULTIVARS PLANTED DIRECTLY OR GRAFTED ON CLAY-SOIL RESISTANT ROOTSTOCK. STUDY OF SOIL FERTILITY, FOLIAR NUTRITION, AND NUTRIENT CONTENT OF CUT FLOWERS

Leucospermum is a genus of the Proteaceae family that has achieved an increasing importance in the market of cut flowers worldwide. Some Leucospemum plants do not grow properly in clay soils, but grafting on a clay-soil resistant rootstock could provide better performances. The nutrient composition of two cultivars of Leucospermum (‘High Gold’ and ‘Succession II’) cultivated in clay soil was evaluated planting them directly or grafting on Leucospermum patersonii rootstock. The assay consisted of four treatments, T1 = ‘High Gold’ planted directly, T2 = grafted ‘High Gold’, T3 = ‘Succession II’ planted directly, and T4 = grafted ‘Succession II’. The experiment was carried out over three years, following a randomized block design with four replications per treatment. Foliar calcium (Ca) decreased in grafted plants of both cultivars. Nitrogen, phosphorus, potassium, Ca, and magnesium contents of the cut-flowers of ‘High Gold’ treatments were higher than those of ‘Succession II’, though in the third year no comparison with T3 plants was possible because most of them had died. The studied nutrients removal by ‘High Gold’ exceeded those of ‘Succession II’.