163,573 research outputs found
James N. Alvarez at Regimental Ball, 1977
No full textBlack-and-white photograph of students at Norwich University's Regimental Ball in November 1977; includes James N. Alvarez (Class of 1978)
CDMF Pesquisa - Román Alvarez Roca
No full text<p> </p>
<p>Román Alvarez Roca, pós-doutorando no Centro de Desenvolvimento de Materiais Funcionais (CDMF), fala de sua pesquisa sobre síntese e caracterização de materiais com ênfase no tungstato de prata.</p>
<p>CDMF Pesquisa - Román Alvarez Roca de <a href="https://youtu.be/wf-g8tfNiDk">https://youtu.be/wf-g8tfNiDk</a> está licenciado com uma Licença <a href="http://creativecommons.org/licenses/by-nc-nd/4.0/">Creative Commons - Atribuição-NãoComercial-SemDerivações 4.0 Internacional</a>. Podem estar disponíveis autorizações adicionais às concedidas no âmbito desta licença em <a href="https://www.labi.ufscar.br/">https://www.labi.ufscar.br/</a>.</p>
Leucothoe hendrickxi Winfield & Alvarez 2009
No full textLeucothoe hendrickxi Winfield & Alvarez, 2009 Leucothoe hendrickxi Winfield & Alvarez, 2009: 17–23, figs 4–6. Type locality and specimens. Pajaros Reef, Veracruz, Mexico, 19°11.63'N 96°5.80'W. Holotype, male, 7.1 mm, CNCR 24844. Material examined. No material available for examination. Diagnosis based on description by Winfield & Alvarez (2009). Diagnosis. Anterior head margin with projection. Maxilliped outer plate tuberculate; palp article 4 apically bifid. Coxae 1, 3–4 distal margins serrate. Gnathopod 1 carpus narrow. Gnathopod 2 basis posterior margin with tuft of three setae. Female (sexually dimorphic characters). Unknown. Habitat. Coral reefs; 13 m. Host. Unknown; collected from artificial substrate. Distribution. Gulf of Mexico: Veracruz, Mexico (Winfield & Alvarez 2009).Published as part of White, Kristine N., 2011, A taxonomic review of the Leucothoidae (Crustacea: Amphipoda) 3078, pp. 1-113 in Zootaxa 3078 (1) on page 55, DOI: 10.11646/zootaxa.3078.1.1, http://zenodo.org/record/524382
Fertilización fosforada de la rotación agrícola y fertilización de forrajeras
No full textLa fertilización fosforada puede decidirse cultivo por cultivo, usando alguno de los modelos de isodosis que permiten una evaluación económica de la práctica. Esto implica que cada año se aplicará o no el fósforo dependido de los precios del fertilizante, del grano y del nivel de fósforo extractable del suelo. Otra alternativa es usar la metodología de reposición y enriquecimiento. En esta se fija un umbral de fósforo extractable a que se quiere llevar el suelo y se fertilizan todos los cultivos para compensar la extracción en grano y llevar el fósforo extractable a ese umbral. Esta última metodología no contempla una evaluación económica de la fertilización y es aplicada principalmente por productores que son propietarios de la tierra o en casos especiales de contratos de locación.Fil: Alvarez, Roberto. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Ingeniería Agrícola y Uso de la Tierra. Cátedra de Fertilidad y Fertilizantes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Leucothoe ortizi Winfield & Alvarez 2009
No full textLeucothoe ortizi Winfield & Alvarez, 2009 Leucothoe ortizi Winfield & Alvarez, 2009: 12–16, figs 1–3. Type locality and specimens. Blanca Reef, Veracruz Mexico, 19°5.17'N 96°0.17'W. Holotype, male, 6.9 mm, CNCR 24840; paratypes, Leucothoe spinicarpa, CNCR 24841, Leucothoe sp. 1, CNCR 24842, Leucothoe sp. 2, CNCR 24843. Material examined. No material available for examination. Diagnosis based on description by Winfield & Alvarez (2009). Diagnosis. Cuspate anterodistal head margin. Coxae 1–3 with serrate distal and posterior margins; coxae 3–4 with serrate anterior margins; coxa 1 with facial setae. Gnathopod 2 carpus recurved, distally rounded; propodus distal margin with blade-like process. Uropod 3 peduncle elongate. Telson apex with weak point or truncate with marginal setae. Female (sexually dimorphic characters). Unknown. Habitat. Coral reefs; 13 m. Host. Unknown; collected from artificial substrate. Distribution. Gulf of Mexico: Veracruz, Mexico (Winfield & Alvarez 2009).Published as part of White, Kristine N., 2011, A taxonomic review of the Leucothoidae (Crustacea: Amphipoda) 3078, pp. 1-113 in Zootaxa 3078 (1) on page 65, DOI: 10.11646/zootaxa.3078.1.1, http://zenodo.org/record/524382
Mobility of toxic elements in carbonate sediments from a mining area in Poland
No full textOspina-Alvarez, N., Głaz, L., Dmowski, K., & Krasnodębska-Ostręga, B. (2014). Mobility of toxic elements in carbonate sediments from a mining area in Poland. Environmental Chemistry Letters, 12, 435–441. doi:10.1007/s10311-014-0468-
The Asymptotic Properties of the System GMM Estimator in Dynamic Panel Data Models When Both N and T are Large
No full textThis paper complements Alvarez and Arellano (2003) by showing the asymptotic properties of the system GMM estimator for AR(1) panel data models when both N and T tend to infinity. We show that the system GMM estimator with the instruments which Blundell and Bond (1998) used will be inconsistent when both N and T are large. We also show that the system GMM estimator with all available instruments, including redundant ones, will be consistent if ƒÐ ƒÅ 2/ƒÐ v2 = 1-ƒ¿ holds.
Métodos estadísticos, variabilidad, interacción
No full textEn Argentina se han desarrollado modelos predictivos de la respuesta a la fertilización usando principalmente metodologías de regresión simple y múltiple. A su vez, las funciones usadas han sido lineales y no lineales. Entre las funciones lineales más comunes puede mencionarse el modelo cuadrático y entre las no lineales el modelo lineal-plateau. Las primeras tienen resolución analítica mientras que las segundas se resuelven por iteración. Las técnicas de ajuste de modelos tienen tres requerimientos para los residuales: normalidad, homogeneidad de varianza e independencia (Kleinbaum y Kupper, 1979, Neter et al., 1990). Se requiere que los residuales tengan una distribución normal, o cercana a la normalidad, para que el test de significancia sea válido. La homogeneidad de varianza es una condición requerida por la técnica de mínimos cuadrados, que se aplica para ajustar los coeficientes de los modelos. De lo contrario, los parámetros ajustados no son los que producen la menor suma global de errores y se subestima la variabilidad asociada a esos parámetros. La independencia de los errores determina que el modelo no esté sesgado por un efecto de sobrepesado de alguna condición particular y los parámetros representen adecuadamente la relación variable independiente vs. dependiente.Fil: Alvarez, Roberto. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Ingeniería Agrícola y Uso de la Tierra. Cátedra de Fertilidad y Fertilizantes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Rodriguezia Alvarez & Villalobos 2018
No full textKey to the species of Rodriguezia 1. Eyes normally developed, pereiopods 2–5 not elongated, epigean.............. R. villalobosi Rodríguez & Manrique, 1967 - Eyes reduced or absent, pereiopods 2–5 elongated, stygobitic................................................... 2 2. Ocular peduncle reduced, not movable, discernible; second to fifth pereiopods, 1.97, 2.5, 2.71 and 2.5 times carapace breadth..................................................................... R. mensabak Cottarelli & Argano, 1977 - Ocular peduncle completely reduced to a plug occupying orbit; second to fifth pereiopods, 1.84, 2.26, 2.48 and 2.21 times car- apace breadth.............................................................................. R. adani n. sp.Published as part of Alvarez, Fernando & Villalobos, José Luis, 2018, A new species of stygobitic freshwater crab of the genus Rodriguezia Bott, 1969 (Crustacea: Decapoda: Trichodactylidae) from Tabasco, Mexico, pp. 137-143 in Zootaxa 4378 (1) on page 142, DOI: 10.11646/zootaxa.4378.1.10, http://zenodo.org/record/116816
Phakellia tropicalis Alvarez & Hooper 2009
No full textPhakellia cf. tropicalis Alvarez & Hooper, 2009 (Fig. 2, 8) Phakellia tropicalis Alvarez & Hooper, 2009: 29; Przeslawski et al. 2014, 2015 (listed only) Material examined. ZMA Por. 0 9017, Indonesia, NE coast of Sumba, E of Melolo, Nusa Tenggara, 9.9033 °S, 120.725 °E, 50 m depth, 15 September 1984, coll. R.W.M. van Soest on Snellius II Expedition, Sta. 061/ V/ 18. ZMA Por. 0 9139, Indonesia, NE coast of Sumba, E of Melolo, Nusa Tenggara, 9.8917 °S, 120.7117 °E, 75 m depth, 13 September 1984, coll. R.W.M. van Soest on Snellius II Expedition, Sta.051, dredge. ZMA Por. 12218, Indonesia, Saleh Bay, N coast of Sumbawa, Lesser Sunda Islands, 8.3166 °S, 117.6833 °E, 274 m depth, 14 February 1900, coll. Siboga Expedition, Sta. 312, trawl. ZMA Por. 0 1226, Indonesia, Lesser Sunda Islands, 8.5 °S, 119.125 °E, 73 m depth, 12 February 1900, coll. Siboga Expedition, Sta. 312, trawl. ZMA Por. 12252, 12268, 12356, Indonesia, Solor Strait, mid channel off Kampong Menanga, Lesser Sunda Islands, 8.4152 °S, 123.043 °E, 113 m depth, 8 February 1900, coll. Siboga Expedition, Sta. 305, dredge. Remarks. The material examined includes a collection of specimens from the area of Lesser Sunda very similar in shape and skeletal organisation to Phakellia tropicalis. The Lesser Sunda specimens are found deeper, down to 274 m depth, than the northern Australian populations, and have thicker and longer spicules. Some specimens are infested with the Parazoanthus. Further illustrations (Fig. 8) and spicules measurements (Table 7) are provided here for comparative purposes. This species was first described from northern Australia and assigned to Phakellia provisionally because it shares characteristic of the skeleton with the dictyonellid genus Acanthella, and surface characteristics with axinellid genera such as Axinella and Cymbastela. The species is genetically related to Axinella and Dragmacidon spp. (Alvarez et al. 2000; Redmond et al. 2013), which are characterized by different morphologies, skeletal organisation and spicule composition. Alvarez & Hooper (2009) also suggested that the species might belong to a new genus which could accommodate species of erect form and ‘bubaris-like’ skeletons currently assigned to hidden Acanthella and Phakellia. Distribution. The species was first described for the Sahul Shelf (with the majority of records reported from northern Australia (i.e Bonaparte Gulf and Arnhem Coast to Gulf of Carpenteria MEOW) (Alvarez & Hooper 2009). It is also found in the Northwest Australian Shelf province (Alvarez & Fromont unpublished data). Assuming that this material is conspecific with P. tropicalis, the distribution of the species is wider than initially thought and should be extended to the Central-Indo Pacific province (Fig. 2). x 3.7–9.5 µm (7 ± 1.6) x 9 –16.4µm (13.8 ± 2) NTM Z004463* Wessel Is 293.1–800 µm (553.4 ± 134.6) 273.6–658.2 µm (439.6 ± 111.1) x 4.4–8.4 µm (6.6 ± 1.1) x 8.3–16 µm (11.2 ± 2.2) QM G 312926 * Papua New Guinea 277.8–696.3 µm (476.4 ± 117.6) [24] 239.6–490.6 µm (343.5 ± 69.5) x 4.2–8.4 µm (6.3 ± 1.1) x 5.9–11.5 µm (8.7 ± 1.8) *Data from Alvarez & Hooper (2009)Published as part of Alvarez, Belinda, De Voogd, Nicole J. & Soest, Van, 2016, Sponges of the family Axinellidae (Porifera: Demospongiae) in Indonesia, pp. 451-477 in Zootaxa 4137 (4) on pages 464-466, DOI: 10.11646/zootaxa.4137.4.1, http://zenodo.org/record/27193
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