Efecto del tránsito agrícola en la anisotropía de las propiedades hidráulicas del suelo

Debido al aumento de la población mundial, la agricultura se posiciona como un actor fundamental capaz de abastecer las demandas crecientes y sostenidas en el tiempo. Es así que Argentina juega un rol importante en la producción mundial dadas sus características edafoclimáticas. Ello se traduce en un uso intensificado del suelo, generando alteraciones físicas. Esto ha llevado a una intensificación del uso del suelo, trayendo como consecuencia problemas de compactación. Este trabajo final de carrera se propone analizar diferentes propiedades físicas que permitan evidenciar dichos problemas. Para ello se realizará en la Estación Experimental Julio Hirschhorn (FCAyF-UNLP) un ensayo de tráfico agrícola de distintas intensidades y en distintas situaciones de humedad del suelo, evaluando el efecto sobre las propiedades físicas y su anisotropía. Se realizarán ensayos de infiltración a campo para determinar la conductividad hidráulica (K), y se extraerán muestras indisturbadas del horizonte superficial en dirección vertical y horizontal. En estas muestras se determinarán la densidad aparente, la curva de retención hídrica y la tasa de infiltración básica a distintas tensiones a través de ensayos de mini-infiltración. Adicionalmente se determinará el contenido de carbono y la textura del horizonte superficial.Ingeniero AgrónomoUniversidad Nacional de La PlataFacultad de Ciencias Agrarias y Forestale

Repelencia al agua en montes de eucalypto de distintas edades y su relación con la materia orgánica

El presente trabajo tiene los siguientes objetivos: i- determinar la hidrofobicidad del suelo en rodales de Eucalyptus spp. de distintas edades; ii- analizar la relación entre la edad del rodal y la repelencia al agua presentada por la capa superficial del suelo; iii- determinar el efecto de la MO del suelo en rodales de diferentes edades sobre la hidrofobicidad y las propiedades físicas.Facultad de Ciencias Agrarias y Forestale

Repelencia al agua en montes de eucalypto de distintas edades y su relación con la materia orgánica

El presente trabajo tiene los siguientes objetivos: i- determinar la hidrofobicidad del suelo en rodales de Eucalyptus spp. de distintas edades; ii- analizar la relación entre la edad del rodal y la repelencia al agua presentada por la capa superficial del suelo; iii- determinar el efecto de la MO del suelo en rodales de diferentes edades sobre la hidrofobicidad y las propiedades físicas.Facultad de Ciencias Agrarias y Forestale

Efecto del tránsito agrícola en la anisotropía de las propiedades hidráulicas del suelo

Debido al aumento de la población mundial, la agricultura se posiciona como un actor fundamental capaz de abastecer las demandas crecientes y sostenidas en el tiempo. Es así que Argentina juega un rol importante en la producción mundial dada sus características edafoclimáticas. Ello se traduce en un uso intensificado del suelo, generando alteraciones físicas y problemas de compactación. Es por esto que se vuelve fundamental analizar diferentes propiedades físicas que permitan evidenciar dichos problemas. Los objetivos de este trabajo fueron: i- determinar los efectos de distintas intensidades de tránsito en condiciones húmedas y secas del suelo sobre la conductividad hidráulica del suelo y la distribución de tamaño de poros; y ii- determinar cambios en la orientación de la configuración del sistema poroso del suelo a través de la medición de la conductividad hidráulica a distintas tensiones en muestras tomadas vertical y horizontalmente.Facultad de Ciencias Agrarias y Forestale

TEFM variants impair mitochondrial transcription causing childhood-onset neurological disease

Mutations in the mitochondrial or nuclear genomes are associated with a diverse group of human disorders characterized by impaired mitochondrial respiration. Within this group, an increasing number of mutations have been identified in nuclear genes involved in mitochondrial RNA biology. The TEFM gene encodes the mitochondrial transcription elongation factor responsible for enhancing the processivity of mitochondrial RNA polymerase, POLRMT. We report for the first time that TEFM variants are associated with mitochondrial respiratory chain deficiency and a wide range of clinical presentations including mitochondrial myopathy with a treatable neuromuscular transmission defect. Mechanistically, we show muscle and primary fibroblasts from the affected individuals have reduced levels of promoter distal mitochondrial RNA transcripts. Finally, tefm knockdown in zebrafish embryos resulted in neuromuscular junction abnormalities and abnormal mitochondrial function, strengthening the genotype-phenotype correlation. Our study highlights that TEFM regulates mitochondrial transcription elongation and its defect results in variable, tissue-specific neurological and neuromuscular symptoms

Can the name Mugil cephalus (Pisces: Mugilidae) be used for the species occurring in the north western Atlantic?

Pacheco-Almanzar, Eloísa, Simons, James, Espinosa-Pérez, Héctor, Carrara, Xavier Chiappa-, Ibáñez, Ana L. (2016): Can the name Mugil cephalus (Pisces: Mugilidae) be used for the species occurring in the north western Atlantic? Zootaxa 4109 (3): 381-390, DOI: http://doi.org/10.11646/zootaxa.4109.3.

Mugil cephalus

<p> <i>Diagnostic characters of Mugil cephalus</i></p> <p>The morphometric data obtained are shown in Table 1. Adults have a thick layer of adipose tissue around the eye, covering most of pupil; hind edge of preorbital does not extend beyond the corner of the mouth. Preorbital extends almost to the end of the maxilla (Figure 2). Both the second dorsal and anal fins have small scales on the basal parts. Anal fin has 3 spines and 8 soft rays in adults (the first spine is very short, and may be hidden under the overlapping scales). Juvenile fish, especially those ≤ 30 mm standard length, usually have 2 spines and 9 soft rays. Pectoral fin with 1 spine and 15 to 16 (rarely 17) soft rays; its length does not reach the origin of the first dorsal fin. The number of scales of the longitudinal series is generally 38–43 (mean 40) for the samples analyzed (reported range worldwide is 36 to 44), and from 12 to 15 in the transverse series (Table 1). The number of gill rakers on the first gill arch is 53–89, showing a positive relationship with standard length.</p> <p>Dorsally, specimens are gray-olive or grayish brown colored. Flanks are silver and the abdomen is whitish; 7 to 10 dark longitudinal stripes are visible along the sides. Dorsal and caudal fins are dark; pelvic and anal fins are pale. The pectoral fins have a dark spot at the origin (Figure 2).</p> <p> <i>Interspecific comparison</i></p> <p> The morphometric measures of <i>M. cephalus</i> and <i>M. liza</i> are shown in Table 1. The mean values of all measurements are similar between the two species except the distance from the snout to the origin of the dorsal fin, which is much larger for <i>M. liza</i>. In this case, the beginning of the dorsal fin is located towards the distal zone while in <i>M. cephalus</i> the beginning of the dorsal fin has an anterior location. Also, the body width is greater in <i>M. liza</i> than in <i>M. cephalus</i>, which appears more robust. This fact has also been recognized by Harrison (2002) who mentions that the ratio of body depth to standard length in <i>M. liza</i> ranges from 17 to 23% while values of 24 to 28% are common in <i>M. cephalus</i>. Even if the majority of the mean values of the morphometric variables are similar, ranges are generally wider in <i>M. cephalus</i>. In <i>M. liza</i>, adipose tissue around eye is almost absent and the hind edge of the preorbital extends beyond the corner of the mouth. The preorbital ends before the end of maxilla (Figure 3). The second dorsal and the anal fin of <i>M. liza</i> have no scales in the basal parts. Anal fin has 3 spines and 8 soft rays in adults; usually 2 spines and 9 soft rays in juveniles about 30 mm or less in standard length in both species.</p> <p> Although the number of transverse, circumpeduncular, and longitudinal scales overlap between the two species, it is possible to distinguish <i>M. cephalus</i> captured in the Gulf of Mexico from <i>M. liza</i> (according to Menezes <i>et al.</i>, 2010) using scale counts. Figures 4 to 6 show that, in general, <i>M. cephalus</i> has a higher number of scales that <i>M. liza; M. cephalus</i> has between 12 and 15 transverse scales with a mode set at 13, while the number of these scales in <i>M. liza</i> ranges from 11 to 14. The number of scales on the circumpeduncular series of the <i>flathead mullet</i> goes from 18 to 23 with a mode at 20, while in the longitudinal series counts range from 38 to 43, with a mode of 40. In <i>M. liza</i>, scales in the circumpeduncular series range from 16 to 20 and in the longitudinal series from 32 to 39. There is almost no overlap between the number of scales in the longitudinal series of both species; only specimens of <i>M. liza</i> with 39 scales could be confused with <i>M. cephalus.</i></p> <p> In the species identification keys of Thomson (1997) and Harrison (2003) the criterion to differentiate between <i>M. cephalus</i> and <i>M. liza</i> is the number of scales in the longitudinal series, being 34 or fewer for <i>M. liza</i> (Thomson, 1997) and greater than 34 for <i>M. cephalus</i> (Harrison, 2003). Misidentification of these two species may be due to the fact that among the mullets of the Western Atlantic, these are the largest and attain similar sizes: <i>M. cephalus</i> reaches 120 cm and <i>M. liza</i> reaches 100 cm.</p> <p> The number of transverse, circumpeduncular, and longitudinal scales of <i>M. cephalus</i> from the Mediterranean coincide with specimens from the Gulf of Mexico (Menezes <i>et al.</i>, 2010). The exception is the upper limit of the range of the number of longitudinal scales, which is greater in individuals caught in the Mediterranean, reaching 38 to 46 (Figures 4 to 6).</p> <p> The number of gill rakers is similar between these two mullets. Within the same length range, the number of gill rakers of <i>M. cephalus</i> varies from 50 to 90 while for <i>M. liza</i> counts fall between 53 and 81. The relationship between the number of gill rakers and standard length was linear, which differs from Menezes <i>et al.</i> (2010) because in this study small specimens of sizes between 10 and 100 mm, which have fewer gill rakers (Figure 7), were analyzed.</p> <p> Harrison (2003) illustrates the presence of <i>M. cephalus</i> in the Gulf of Mexico, which is supported by data presented here; Álvarez-Lajonchere (personal communication) does not accept that its distribution range reaches the Caribbean Sea. The presence of <i>M. liza</i> in the Caribbean has been shown by Álvarez-Lajonchere (1978a; 1978b), and its presence is confirmed in the Gulf of Mexico with specimens catalogued as CNPE-IBUNAM 757 captured in the coastal waters of Veracruz, Mexico, as well as other evidence documented by Castro-Aguirre <i>et al.</i> (1999).</p> <p> The meristic and morphometric measures of <i>M. liza</i> from the Gulf of Mexico are contained within the ranges showed by Menezes <i>et al.</i> (2010). No comparison of Mexican samples was included in figures and tables here since only seven specimens were reviewed in the Gulf of Mexico and this could bias the information.</p> <p> <i>Variation in the number of scales of</i> Mugil cephalus <i>in the Gulf of Mexico</i></p> <p>Morphometric measurements were not significantly in different individuals from different sites along the coast of the Gulf of Mexico. However, the number of scales of the transverse and longitudinal series (p <0.05) was significantly different among sites. Although the median number of scales in the longitudinal series is identical in six of the seven sites, there is a pattern that emerges considering specimens obtained from sites in Florida (FL), Alabama (AL), and Mississippi (MS) and those caught in Louisiana (LA), Texas (TX), and Veracruz (VE). Differences seem to be determined geographically by the coastal areas east and west of the Mississippi River. The number of scales in the longitudinal series of specimens caught in Yucatan (YU) is different from the others (Figure 8).</p> <p>The number of scales in the transverse series shows differences in individuals obtained east and west of the Mississippi River. The most frequent number of scales in the transverse series for individuals from locations in Louisiana, Mississippi, Alabama, and Florida was 13 scales, found in 62.8 to 79.2% of the specimens analyzed. In the southern areas, such as Texas, Tamaulipas, and Veracruz, 14 transverse scales were counted in 77.2%, 91.1%, and 69.5% of analyzed specimens. In individuals from Yucatán, 13 transverse scales were counted more frequently (Table 2).</p> <p> According to our data, a pattern of variation exists in individuals obtained east and west of the mouth of the Mississippi. Those from Yucatan have unique characteristics relative from specimens obtained in other Gulf sites particularly when considering the number of scales in the longitudinal series. A microsatellite study conducted by Colin (2014) suggests that there is a trend in the genetic differentiation that supports the hypothesis that, within the Gulf of Mexico, this species is structured with at least three subgroups: the Mississippi, the Caribbean, and the Gulf, possibly separated by the prevailing circulation pattern. Zavala-Hidalgo <i>et al.</i> (2003) noted that there is a seasonal current from Louisiana and Texas towards Tamaulipas and Veracruz, which is well established from September to March; a reverse direction is observed from May to August. Different counts in the scales both of the longitudinal and transverse series were found in individuals from these two areas.</p> <p> In conclusion, morphometric and meristic results are evidence of the presence of <i>M. cephalus</i> in the Gulf of Mexico and clarify doubts on its distribution in the northwest Atlantic. The sympatric presence of <i>M. liza</i> is confirmed although its abundance seems to be low.</p>Published as part of <i>Pacheco-Almanzar, Eloísa, Simons, James, Espinosa-Pérez, Héctor, Carrara, Xavier Chiappa- & Ibáñez, Ana L., 2016, Can the name Mugil cephalus (Pisces: Mugilidae) be used for the species occurring in the north western Atlantic?, pp. 381-390 in Zootaxa 4109 (3)</i> on pages 383-388, DOI: 10.11646/zootaxa.4109.3.8, <a href="http://zenodo.org/record/262542">http://zenodo.org/record/262542</a&gt

Cuantificación y caracterización del flujo preferencial en laboratorio

El flujo preferencial (FP) es un fenómeno en el cual el agua que ingresa al suelo se desplaza rápidamente a través de vías preferenciales (bioporos y grietas) no quedando retenida en la matriz del suelo, esto deriva en un movimiento de agua y solutos hacia horizontes más profundos no quedando disponible para los cultivos. En la bibliografía se mencionan numerosas metodologías para su determinación y cuantificación siendo estas costosas (tomografía) o destructivas (seguimiento de tinturas). En este trabajo se propone una metodología en laboratorio para poder determinar la presencia de FP en muestras de suelo no disturbadas de manera rápida, repetible y con el menor costo posible. Los objetivos son: i - Elaborar una metodología en laboratorio que permita detectar la presencia de FP en muestras indisturbadas, ii – Inferir la presencia de FP mediante la utilización de sensores de humedad y potencial mátrico.Facultad de Ciencias Agrarias y Forestale

Heuristics for planning with penalties and rewards formulated in logic and computed through circuits

The automatic derivation of heuristic functions for guiding the search for plans is a fundamental technique in planning. The type of heuristics that have been considered so far, however, deal only with simple planning models where costs are associated with actions but not with states. In this work we address this limitation by formulating a more expressive planning model and a corresponding heuristic where preferences in the form of penalties and rewards are associated with fluents as well. The heuristic, that is a generalization of the well-known delete-relaxation heuristic, is admissible, informative, but intractable. Exploiting a correspondence between heuristics and preferred models, and a property of formulas compiled in d-DNNF, we show however that if a suitable relaxation of the domain, expressed as the strong completion of a logic program with no time indices or horizon is compiled into d-DNNF, the heuristic can be computed for any search state in time that is linear in the size of the compiled representation. This representation defines an evaluation network or circuit that maps states into heuristic values in linear-time. While this circuit may have exponential size in the worst case, as for OBDDs, this is not necessarily so. We report empirical results, discuss the application of the framework in settings where there are no goals but just preferences, and illustrate the versatility of the account by developing a new heuristic that overcomes limitations of delete-based relaxations through the use of valid but implicit plan constraints. In particular, for the Traveling Salesman Problem, the new heuristic captures the exact cost while the delete-relaxation heuristic, which is also exponential in the worst case, captures only the Minimum Spanning Tree lower bound.H. Geffner is partially supported by grant TIN2006-15387-C03-03 from MEC/Spain and B. Bonet by a grant from DID/USB/Venezuela. Our planner was built upon a planner by Patrik Haslum. Preliminary experiments were run on the Hermes Computing Resource at the Aragon Institute of Engineering Research (I3A), University of Zaragoza