Spatiotemporal Stacked Sequential Learning for Pedestrian Detection

Pedestrian classifiers decide which image windows contain a pedestrian. In practice, such classifiers provide a relatively high response at neighbor windows overlapping a pedestrian, while the responses around potential false positives are expected to be lower. An analogous reasoning applies for image sequences. If there is a pedestrian located within a frame, the same pedestrian is expected to appear close to the same location in neighbor frames. Therefore, such a location has chances of receiving high classification scores during several frames, while false positives are expected to be more spurious. In this paper we propose to exploit such correlations for improving the accuracy of base pedestrian classifiers. In particular, we propose to use two-stage classifiers which not only rely on the image descriptors required by the base classifiers but also on the response of such base classifiers in a given spatiotemporal neighborhood. More specifically, we train pedestrian classifiers using a stacked sequential learning (SSL) paradigm. We use a new pedestrian dataset we have acquired from a car to evaluate our proposal at different frame rates. We also test on a well known dataset: Caltech. The obtained results show that our SSL proposal boosts detection accuracy significantly with a minimal impact on the computational cost. Interestingly, SSL improves more the accuracy at the most dangerous situations, i.e. when a pedestrian is close to the camera.Comment: 8 pages, 5 figure, 1 tabl

Analysis of inequality in fertility curves fitted by gamma distributions

The aim of this paper is to analyse fertility curves from a novel viewpoint, that of inequality. Through sufficient conditions that can be easily verified, we compare inequality, in the Lorenz and Generalized Lorenz sense, in fertility curves fitted by gamma distributions, thus achieving a useful complementary instrument for demographic analysis. As a practical application, we examine inequality behaviour in the distributions of specific fertility curves in Spain from 1975 to 2009.Peer Reviewe

Validation and Adaptation of the Prosocial and Antisocial Behavior in Sport Scale to the Spanish context of Physical Education

Physical education (PE), by its own characteristics, is a subject where social communication is especially promoted. However, it is necessary to have tools that evaluate the social behaviour of students during PE classes. For this reason, we propose to validate and adapt the Prosocial and Antisocial Behavior in Sport Scale to the Spanish context of PE classes. The study involved 1081 students aged 12 to 18 (M = 14.83; SD = 1.27). The psychometric properties of the Prosocial Behavior Scale were analyzed through several statistical analyses. The results of the confirmatory factorial analysis and the exploratory factorial analysis supported the internal structure of the questionnaire. In addition, the scale was invariant to gender. Cronbach’s alpha values were higher than 0.70 in the factors and sub-factors, finally showing adequate levels of temporal stability. Taking into account the results achieved in the present study, PE teachers have an effective tool to assess the social and antisocial behaviour of their students’ students during PE classes

Ab initio investigation of the H2O2 + F elementary reaction

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Yerbicidas potenciales para combatir la yerba peluda en los cañaverales de Puerto Rico

Field trials in 1986-87 were conducted in the humid sugarcane growing area of San Germán and under irrigation at the Lajas Research and Development Center to evaluate several candidate herbicides for controlling itchgrass (Rottboellia exaltata L.f.) in sugarcane fields. Terbutryn [2—(Tert— butylamino)—4— (ethylamino)—6— (methylthio— S—triazine] at 2.68, 5.35 and 10.70 kg/ha as a direct post emergence application over itchgrass 15 to 20 cm tall provided excellent grass control with no injury to the crop. Asulam [methyl (4 amino phenyl) (sulfanyl)] carbamate at 2,09 kg/ha showed a slow short-term action. With Terbutryn at 10.7 kg/ha and the hand-weeded check plots significantly higher cane and sugar yields were obtained, Pendimethalin [N—(ethylpropyl)—3,4—dimethyl—2,6—dinitroben— zenamine] at 3.56 kg/ha as a preemergence soil-in corpora ted application to a primavera sugarcane crop was effective in controlling itchgrass. A single application of this product at 1.78 kg/ha was markedly less effective. Imazapyr (2-[4,5 dihydro—4—methyl—4—(l-methylethyl)—5—0x0—lH—imidazolzyl]— 3—pyridinecarboxylic acid) with 2—propanamine (1:1) salt at 0.125 and 0.25 kg/ha controlled of itchgrass excellently. Combinations of pendimethalin and imazapyr were effective in controlling grass weeds. The best cane tonnage and sugar yields were obtained from the hand-weeded plots and from combinations of pendimethalin and imazapyr. With pendimethalin at 0.89 and 1.78 kg/ha and asulam at 2.98 kg/ha there was very little effect from the herbicide treatments on increasing yield.En 1986-87 se establlcieron dos experimentos de campo en la zona cañera húmeda de San Germán y en el Centro de Desarrollo e Investigaciones de Lajas (regadío) para evaluar varios herbicides potenciales para combatir la yerba peluda (Rottboellia exaltata) en los cañaverales. Terbutrin en aplicaciones postemergentes dirigidas a la yerba peluda de 15 a 20 cm. de altura la repimió eficazmente cuando se la aplicaron entre 2.68 y 10.70 kg./ha. Estas dosis no les causaron daños visibles al retoño en la zona humeda de San Germán. Asulam usado como herbicida patrón fue lento y efímero en la represión de gramíneas en este experimento. Las parcelas testigo, desyerbadas a mano y asperjadas con terbutrin a 10.70 kg./ha., produjeron significativamente más toneladas de caña y de azúcar por hectárea que los demás tratamientos. Todas las parcelas tratadas con herbicidas produjeron significativamente más toneladas de caña por hectárea que el testigo sin desyerbar, excepto terbutrin a 1.34 kg./ha. Pendimetalin a razón de 3.56 kg./ha., incorporado al terreno en aplicación preemergente, fue muy eficaz para reprimir la yerba peluda y otras gramíneas. Cuando se aplicó terbutrin a razón de 1.78 kg./ha., redujo marcadamente su eficacia a menos de 50% a las 10 semanas de aplicado. Imazapir a razón de 0.125 y 0.25 kg./ha. y en combinaciones de terbutrin fue excelente para la represión de gramíneas en este experimento en el Centro de Desarrollo e Investigaciones de Lajas. Los rendimientos más altos, en término de toneladas de caña y azúcar por hectárea, se obtuvieron con el testigo desyerbado a mano y las combinaciones de terbutrin e imazapir. El rendimiento del testigo sin desyerbar fue significativamente inferior a los tratamientos con herbicidas

Rendimiento de maní rizoma perenne (Arachis glabrata) cosechado a seis, nueve y 12 semanas en dos localidades semiáridas.

Rhizoma perennial peanut (RPP) is a forage legume of excellent adaptability and persistence «»nder subtropical and tropical conditions. Four accessions (USDA-TARS 17033,17050, 17052, and 17097, with PI nos. 276233, 262826, 262833, and 262839, respectively) and two cuitivars (Arbrook and Florigraze) of rhizoma perennial peanut (RPP) in Lajas, and two of the accessions (17033 and 17097) and cultivar Florigraze in Juana Díaz, Puerto Rico, were evaluated for dry matter yield (DMY) under irrigation during a full year.The RPPs were evaluated at six-, nine- and 12-wk harvest intervals (HI) in each of the four seasons of the year. At both sites, yield of accession 17033 was highest (P < 0.01) and averaged 35,779 kg DM/ha/yr. In Lajas, yield of accession 17097 was second best with an average of 30,151 kg DM/ ha/yr, yields of the other four RPPs were similar, averaging 25,374 kg DM/haV yr. Cultivar Florigraze, which produced 16% less than accession 17097 in Lajas, had similar productivity in Juana Díaz. On average, the total yields of accessions 17033 and 17097 and cultivar Florigraze declined (P < 0.01) by about 35 and 27% at the two locations, respectively, as HI increased from six to 12 weeks. Season of harvest had a strong influence on the DMY of RPP. At both locations, 69 and 64% of total yields were produced during spring and summer, respectively. Differences in height among RPPs were significant (P < 0.01) at both locations. Height averaged 26.0,17.6, and 18.5 cm for accessions 17033 and 17097 and cultivar Florigraze, respectively. The great adaptability of RPP to the tropical environment, and its high yield when harvested for hay, make it a crop with the potential of becoming one of the most important forages in the tropics.Cuatro accesiones (USDA-TARS líneas núm. 17033, 17050, 17052 y 17097; núm. Pl 276233, 262826, 262833 y 262839, respectivamente) y dos cultivares (Arbrook y Florigraze) de maní rizoma perenne (MRP) en Lajas, y dos accesiones {17033 y 17097) y Florigraze en Juana Díaz» Puerto Rico, se evaluaron para rendimiento de materia seca durante un año, en años consecutivos. Los MRP fueron evaluados a intervalos entre cosechas de seis, nueve y 12 semanas en cada una de fas estaciones del año. En ambas localidades el rendimiento de materia seca (WIS) de la accesión 17033 fue mayor (P < 0.01), promediando 35,779 kg MS/ha/año. En Lajas, el rendimiento de ía 17097 fue el segundo mayor con 30,151 kg MS/ha/año y el de los otros cuatro MRP fue similar y menor que et rendimiento de 17097, promediando 25,374 kg MS/ha/año. Florigraze produjo 16% menos MS que la 17097 en Lajas; sin embargo, en Juana Díaz la producción de las dos fue similar. A medida que el intervalo de cosecha se aumentó de seis a 12 semanas el rendimiento promedio de la 17033,17097 y Florigraze se redujo {P < 0.01) en alrededor de 35 y 27% en Lajas y Juana Díaz, respectivamente. En ambas localidades el 69 y el 64% del redi miento total de MS se produjo en la primavera y el verano, respectivamente. Las diferencias en la altura de la planta entre los MRP fueron significativas (P < 0.01) en ambas localidades. La altura promedio de las plantas fue 26.0, 17.6 y 18.5 cm para las accesiones 17033 y 17097, y Florigraze, respectivamente. La gran adaptabilidad del MRP al medio ambiente tropical y su alto rendimiento, cuando es cosechado para heno, hacen del mismo un cultivo con el potencial de ser uno de ios forrajes de mayor importancia en el trópico

Screening for candidate bacterial biocontrol agents against soilborne fungal plant pathogens

Over the years, many bacterial isolates have been evaluated as potential biocontrol agents against soilborne fungal phytopathogens. However, few of them were ultimately successful after evaluation in field trials. One of the major reasons for this failure is the lack of appropriate screening procedures to select the most suitable microorganisms for disease control in diverse soil environments. For this reason, the study of bacterial screening has a future that is characterised by many technical and conceptual challenges. In this review, we summarise and discuss the convenience of use of the main screening methods currently applied to select bacterial candidates for biocontrol of fungal and oomycete soilborne phytopathogens. Also, a comparative case study of the application of different screening methods applied to an experimental pathosystem is shown, revealing the success of bacterial candidates selected by different strategies for biocontrol of the phytopathogenic fungus Rosellinia necatrix in avocado plants. Screening for antagonism against this fungal pathogen, one of the more straightforward methods used for the selection of bacterial biocontrol agents, was proven to be a valid strategy for this experimental system