Browsing by Author "Albornoz, Francisco"

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    High Nitrogen Fertilization Decreases Seed Weight but Increases Longevity in Tomato Seeds
    (2022) Sanchez, Javier; Albornoz, Francisco; Contreras, Samuel
    Nitrogen fertilization is a key practice in agriculture and its effects on yield and quality of most commodity products are widely known. However, the response of seed production to N fertilization, especially with regard to its effects on seed quality, is still poorly understood. The objective of this study was to determine the effect of N fertilization on tomato seed yield and quality. Six quality attributes were assessed (weight, standard germination, germination rate under normal and adverse conditions, dormancy and longevity) in tomato cv. Moneymaker plants fertigated with one of three nutrient solutions differing in their N concentration: 5, 15 or 25 mM. Seed weight decreased by 4% with increasing N fertilization while standard germination and mean germination time did not vary among treatments, with average values of 89.7% and 6.2 days, respectively. The percentage and rate of germination decreased when seeds were imbibed in solutions with reduced osmotic potential; however, this effect was less pronounced in seeds from the 25 mM treatment, indicating a lower dormancy. When germination was evaluated after accelerated aging, seeds from the high N fertilization treatment showed greater longevity. These results contribute to optimizing fertilization practices for the production of high quality tomato seeds.
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    Resultados Chilenos del registro internacional de factores de riesgo y tratamiento de angina inestable e infarto al miocardio sin supradesnivel del segmento ST: ACCORD (ACute CORonary syndrome Descriptive study)
    (SOC MEDICA SANTIAGO, 2011) Stockins, Benjamin; Albornoz, Francisco; Martinez, Dario; Campos, Pabla; Gajardo, Jorge; Lamich, Ruben; Manriquez, Leopoldo; Perez, Victor; Rojo, Pamela; Sepúlveda Varela, Pablo Andrés; Gabriela Pumarino, M.; Corbalan, Ramon
    Background: Guidelines for the management of unstable angina (UA) and non ST elevation myocardial infarction (NSTEMI) have been issued, however current practices are unknown in Chile. Aim: To evaluate in a prospective cohort of NSTEMI patients the current practices, treatments and risk factors. Material and Methods: One year prospective International non interventional registry, conducted in Chile between January 2005 and November 2006. Results: Two hundred thirty three Chilean NSTEMI patients were enrolled. Mortality was 5.5% at the end of the follow-up. Mean age was 61.6 years, and 30.6% were female. Most of the patients had at least one risk factor (98%): hypertension (84%), previous myocardial infarction (33%), dyslipidemia (54%), diabetes (33%), current smoking (30%). Main procedures during the hospitalization were coronary angiogram (67%), angioplasty (33%; 88% with stent) and coronary bypass surgery (7%). During procedures, 31% of patients received clopidogrel, and 4.2% glycoprotein IIb/IIIa antagonists. Medical management was selected for 60% of patients. In comparison to men, women received less interventional procedures despite having more risk factors. Treatments prescribed at discharge were aspirin (97%), clopidogrel (49%), beta blockers (78%), diuretics (21%), lipid lowering agents (78%), oral hypoglycemic agents (13%) and insulin (9%). At the end of the 1-year follow-up, treatments were aspirin (84%), beta blockers (72%), diuretics (19%), and dual antiplatelet therapy with clopidogrel (16%). Conclusions: A high prevalence of multiple risk factors for cardiovascular disease in Chilean patients with NSTEMI was observed. More aggressive primary and secondary preventive measures are urgently needed. Use of therapies proposed in the guidelines is high, but dual antiplatelet therapy is less than 50% at discharge and decreases during the one year-follow-up. (Rev Med Chile 2011; 139: 19-26).
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    Seeds Yield and Quality of Quinoa ( Chenopodium quinoa Willd.) Plants Grown Under Different Nitrogen Fertilization Doses
    (2024) Contreras, Samuel; Molina, Jorge; Garcia, Margarita; Sanchez, Javier; Chorbadjian, Rodrigo; Fuentes, Francisco; Albornoz, Francisco
    S. Contreras, J. Molina, M. Garc & iacute;a, J. S & aacute;nchez, R. Chorbadjian, F. Fuentes, and F. Albornoz. 2024. Seeds Yield and Quality of Quinoa (Chenopodium quinoa Willd.) Plants Grown Under Different Nitrogen Fertilization Doses. Int. J. Agric. Nat. Resour. 68-74. Quinoa ( Chenopodium quinoa Willd.) has been cultivated for more than 7,000 years in the mountain regions (Andes Mountains) of South America. Five ecotypes differing in their phenology, morphology and stress resistance can be found. One of these ecotypes corresponds to the coastal ecotype, which is cultivated mainly in Chile. Little information is available regarding the response of this ecotype to nitrogen (N) fertilization. In the present study, three N fertilization doses (low: 30, adequate: 140 and high: 280 kg ha -1 ) were evaluated in plants grown in containers. Seed yield and quality attributes, including seed weight, nitrate content, germination, and seed longevity, were evaluated. These results indicate that increasing N fertilization promotes increases in seed yield and weight. In terms of seed quality, although the fertilization treatments did not affect germination, seed longevity was reduced by increasing the N fertilization dose.
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    Soilless Production of Lettuce (Lactuca sativa) in the Atacama Desert Using Fog Water: Water Quality and Produce Mineral Composition
    (2024) Albornoz, Francisco; Vilches, Ines; del Rio, Camilo; Carter, Virginia
    Soilless vegetable production in the Atacama Desert of Northern Chile is spreading since it is perceived as an alternative that requires much less water than open field soil production. However, strong competition between mining and urban use for human population consumption exists, forcing growers to use alternative water sources. Fog is commonly present in the coastal areas of Northern Chile; however, little information exists with regards to its chemical composition and the effect on nutrient quality of the produce. To address this knowledge gap, a set of experiments was carried out in Cha & ntilde;aral, a small town located in the Atacama Desert of Northern Chile. There, a 200 m(2) greenhouse equipped with twenty deep flow pools was used in two consecutive growing cycles. Water for the mixing of the nutrient solution was collected from the fog using fog-catchers and later stored in 2000-L tanks. Fog water quality (electrical conductivity, pH and mineral content) was monitored directly from the storage tanks. Two types of lettuce, green butterhead and red oak leaf, were compared on their yield and accumulation of nutrients and heavy metals. The results indicate that fog water is of good quality for soilless production, with an electrical conductivity value of 0.65 +/- 0.18 and low content of heavy metals. Plants' heavy metal accumulation is below the recommendation of Food and Agriculture Organization and World Health Organization. Fog water presents as a viable water source for soilless production in Northern Chile.