Híbridos nuevos en el género "Teucrium l." (laniaceae)

Se describen cuatro nuevas nothoespecies del género Teucrium L. (Sect. Polium) para el sureste de España: T. x rigualii (T. libanitis x T. carolipaui), T. x riosii (T. capitatum subsp. gracillimumxT. carolipaui), T.xriverae (T. capitatum subsp. gracillimumxT. dunense), yT. x robledoi (T. capitatum subsp. gracillimumx T. homotrichum). Asimismo se aportan datos sobre la posición bioclimática, biogeográfica y fitosociológica de cada uno de ellos

Notas fitosociológicas sobre el sudeste ibérico

Se da cuenta de algunos sintaxones nuevos del SE de Espana y más concretamente de la provincia de Alicante (Teucrio-Ulicetum dianii nova, subasociación típica, erinacetosum y ononidetosum; Querco-Pistacietum lentisci (Br.-81., 1935) A. et O. Bons 1950 viburnosum tini var. nova). Así mismo se proponen una combinación nueva (Daphno-Festucetum capillifoliae O.Bolós et Rigual 1967 stipetosum tenacissimae (Alcaraz et Rivas-Martínez in Alcaraz 1984) comb. nova y el nombre corregido de otra (Jasonio-Teucrietum thymifolii (Rigual, Esteve et Rivas Goday 1962) corr.As a result of phytosociological investigation on the "Sierra del Maigmó" (Alicante, Spain) we described a new association (Teucrio�Ulicetum dianii) with some subassociations. We make a new combination and, according to the Code of Phytosociological Nomenclature, we propose the correction of Jasonio�Teucrietum thymifolii

Calculation of threshold Olsen P values for fertilizer response from soil properties

Phosphorus (P), a non-renewable resource, needs to be used more efficiently in agriculture. This requires using soil P tests. However, the P test threshold values for fertilizer response depend on many soil properties, some of which may be useful to estimate these threshold values, others not. Therefore, we searched here which soil properties are useful to estimate P threshold values. We calculated the threshold values for Olsen P and 0.01 M CaCl2 extractable P of 18 representative agricultural soils of the Mediterranean region of Spain. For that, we performed a P starvation experiment in which wheat and sunflower were alternatively pot-cropped. Results show that Olsen P threshold values are negatively correlated to P buffer capacity (r of −0.74, P lower than 0.001), clay content (−0.82, 0.001), pH (−0.76, 0.001), and Fe oxide content (−0.55, 0.05). Multiple regression models involving clay, pH or soil organic C, and phosphatase activity or organic hydrolysable P accounted for as much as 87 % of the variance in calculated Olsen P threshold values. In particular, there is a major effect of organic P on Olsen P threshold values. Single models based on routinely measured soil properties such as clay content and pH made accurate predictions of Olsen P threshold values with r 2 of 0.81 and P lower than 0.001

Using Markov-Switching models in Italian, British, U.S. and Mexican equity portfolios: a performance test

In this paper we test the use of Markov Switching models in equity trading strategies, following Brooks and Persand (2001), Kritzman et al. (2012) and Hauptmann et al. (2014), who suggest their use as warning systems of bad performing periods. We extend their reviews by testing again (with the impact of trading fees) the U.S. and U.K. markets and by extending our tests to the Italian and Mexican case. The rationale behind our Markov-Switching strategy is to invest in equity index tracking ETFs in low volatility or ”good performing” periods and in the local risk-free asset in high-volatility or ”bad performing” ones. Our results show that in a weekly simulation from January 4, 2001 to July 30, 2017 with a 0.35% trading fee plus taxes, our system is useful to create alpha in all the simulated markets even if the Italian case showed several deep distress moments due to a financial or political crisis

An EM/MCMC Markov-witching GARCH behavioral algorithm for random-length lumber futures trading

This paper tests using two-regime Markov-switching models with asymmetric, time-varying exponential generalized autoregressive conditional heteroskedasticity (MS-EGARCH) variances in random-length lumber futures trading. By assuming a two-regime context (a low s=1 and high s=2 volatility), a trading algorithm was simulated with the following trading rule: invest in lumber futures if the probability of being in the high-volatility regime s=2 is lower or equal to 50%, or invest in the 3-month U.S. Treasury bills (TBills) otherwise. The rationale tested in this paper was that using a two-regime Markov-switching (MS) algorithm leads to an overperformance against a buy-and-hold strategy in lumber futures. To extend the current literature in MS trading algorithms, two location parameter scenarios were simulated. The first uses an unconditional mean or expected value (no factors), and the second incorporates market and behavioral factors. With weekly simulations form 2 January 1994 to 28 July 2023, the results suggest that using MS-EGARCH models in a no-factors scenario is appropriate for active lumber futures trading with an accumulated return of 158.33%. Also, the results suggest that it is not useful to add market and behavioral factors in the MS-GARCH estimation because it leads to a lower performance.Junta de Extremadura | Ref. GR2116

Acueducto de Segovia: Comportamiento mecánico

Informe destinado a aportar luz sobre algunos aspectos de la mecánica del Acueducto de Segovia: tensiones y deformaciones derivadas de las variaciones térmicas diarias y estacionales y alteraciones de los campos de tensión derivados de las degradaciones típicas de las juntas. Se aportan entre otros resultados explicaciones a la frecuente existencia de fisuras en prolongación de las juntas, asi como evidencia sobre fenómenos mecánicos que coadyuvan en el proceso de desescamación de los sillares degradados