218 research outputs found
Changes in Defoliation Patterns of Plant Functional Groups under Variable Herbage Allowance in Campos Grasslands
Several studies have evaluated separately forage production, botanical composition, leaf traits and animal performance. However, few of them have focused on defoliation patterns at the level of functional groups (FGs) under different and variable herbage allowance (HA), especially in natural, diverse grasslands. The objective was to evaluate the relationship between HA and leaf traits on defoliation patterns of mature beef cows in the autumn, winter and spring. We evaluated the grazing probability (GP), intensity of defoliation (ID), and leaf traits on 14 species that represent more than 80% of total dry matter of the pasture. The experiment at which we evaluated those traits and responses has been managed under High HA (HHA) and Low HA (LHA) (8 and 5 kg dry matter kg live weight-1, respectively). Four plant FGs (A, B, C and D) were defined according to leaf traits, and a selectivity index (SI) was developed for each group (considering the proportion of grazed and ungrazed species). Grazing patterns shifted across seasons. In the autumn, grazing was concentrated on FGs A, B and C groups (GP = 0.417). While for FG D, represented by high-biomass tussocks, the GP was lower (0.075). During winter, when herbage accumulation rate is limited, the average GP was 0.175. FGs C and D were more defoliated in relation to autumn, and during spring the GP shifted to FG B (0.289). The ID was similar to all FGs and seasons (66 % of leaf removed). In autumn and spring, the SI was affected by FGs and HA while in winter were similar between FGs but higher in HHA. Cows behaved differently in the defoliation pattern, modifying mainly the GP on FGs rather than the ID. Variation in HA across season determined changes in defoliation pattern, allowing to express selectivity in autumn and spring
Effect of Native Grassland Intensification over Cattle Performance
The objective was to evaluate the effect of different levels of intensification in native grassland over cattle live weight gain (LWG), stocking rate (SR) and average daily gain (ADG) in Uruguay. The study was carried out in 7.8 ha in Paysandú, between winter 2015 and autumn 2019. Experiment was a randomized complete block design, with 4 replicates. The four treatments applied were native grassland (NG), NG overseeded with Trifolium pratense (6 kg.ha-1) and Lotus tenuis (6 kg.ha-1) + 40 kg.ha-1 of P2O5 (NGO), NG fertilized with 60 kg.ha-1 of N + 40 kg.ha-1 of P2O5 (N60) and NG fertilized with 120 kg.ha-1 of N + 40 kg.ha-1 of P2O5 (N120). Fertilizers used were urea and a blend of 7-40/40-0-4. Animals were growing Holstein steers, with initial live weight of 180 ± 22 kg. Treatments management consisted of rotational stocking system, subdivided in 4 plots, according to blocks. Grazing periods were 14 ±1 day, and rest periods were 45 ±2 days, totaling a grazing cycle of 60 days. The average area of the plots of NG and NGO treatments was 0.72 ha while the treatments of N60 and N120 was 0.26 ha. The SR was significantly different between treatments (P = 0.066). The SR in N60 was 868 ±85 kg LW.ha-1, in N120 was 856 ±124 kg LW.ha-1, in NGO was 583 ±91 kg LW.ha-1 and in NG 544 ±40 kg LW.ha-1. The ADG was not different between treatments (P = 0.372), averaging 0.472 kg LW.animal-1.day-1. The LWG was different between treatments (P = 0.050). The LWG was higher in N60 (432 ±107 kg LW.ha-1.year-1), intermediate in N120 (391 ±91 kg LW.ha-1.year-1) and NGO (306 ±148 kg LW.ha-1.year-1) and lower in NG (206 ±63 kg LW.ha-1.year-1). Increasing levels of intensification in native grassland allow higher ADG and SR, determining higher LWG
First report of egg predation by an unpaired Eurasian Coot, Fulica atra, L., 1758 (Aves: Gruiformes) on Black-winged Stilt, Himantopus himantopus, L., 1758 (Aves: Charadriiformes): one case from central Italy
The Eurasian Coot, Fulica atra, is a gregarious Palearctic rail that only rarely occurs singly. Even if resident birds can present territorial behaviour all through the year, most aggressions are developed during the breeding season, and the scientific literature has reported inter- and intraspecific attacks by Coot breeding pairs. Unpaired individuals do not usually show any territoriality and are often subjected to attacks by breeding pairs. It is, however, possible to observe unpaired Coots defending a territory before pairing, but the typical aggressive behaviour is developed after the beginning of nest building. Egg predation by Coots is reported as a rare phenomenon, exerted only by members of breeding couples. In this note, we report two predation cases exhibited by an unpaired individual against nests and eggs of Himantopus himantopus. We discard the hypothesis of competition for food between these two species and suggest that this peculiar behaviour could have been induced by endocrine hormonal secretions, regardless of whether the individual was paired or not. © 2013 Copyright Unione Zoologica Italiana
Leaf Fragment Identification of Subtropical Native Grass Species
The present study was carried out to characterise leaf fragments of important plant species of a subtropical native sward in the southernmost state of Brazil. Thirteen important grass species were collected from April to May 1999. Both sides of the leaves were observed using a stereomicroscope. In addition, two approaches were tested to provide a clearer characterisation of the leaves of each species: the leaves were either dried or frozen. The kind and number of veins, the kind and number of hair, and the arrangements and number of stomates on both sides of each leaf are the most useful characteristics to differentiate fragments of native grass species’ leaves. These characteristics can be more easily observed when the plant material is dried
Motivating learners through information literacy
This paper is included in the Information Literacy: Key to an Inclusive Society, the proceedings of the European Conference on Information Literacy, 2016. The paper introduces a model for creating information literacy learning activities that motivate students. The model draws from informed learning, an approach to information literacy that emphasizes the role that information plays in fostering learning about a subject. Self-determination theory, a motivational theory that focuses on enabling self-determined learners, is applied within the informed learning framework. The results of the investigation outline characteristics of motivating learning activities that enable learning subject content through engagement with information. The model is intended to be used by librarians when working with classroom teachers to foster greater student learning gains through creative and reflective engagement with information
Assessment of the current distribution of free-living parrots and parakeets (Aves: Psittaciformes) in Italy: A synthesis of published data and new records
Parrot species are often introduced outside of their native distribution range, as they are among the most popular pets worldwide. Releases, and particularly unplanned escapes, have resulted in the establishment of many naturalised populations in Europe, including Italy. Many parrot species present wide ecological tolerance and high synanthropy, but the knowledge of their distribution in the areas of introduction is limited. The introduction of these species may have a negative impact on local biodiversity, particularly in terms of competition with hole-nesting birds and bats, crop damage and epidemiology, so that it has become crucial to provide accurate and up-to-date research on the distribution of these taxa. This work aimed at reporting the occurrence points of the various Psittaciformes species in Italy. Records for 21 species (72.41% of those reported for all of Europe) were collected, with five of them breeding, always close to urban centres. © 2013 Copyright 2013 Unione Zoologica Italiana
Mindfulness, mental health, and motives for eating tasty foods when not in metabolic need
Habitual consumption of highly palatable foods when not in metabolic need (HPF eating) is linked to obesity. High HPF consumption is also linked to mental health disorder (MHD) symptoms. Mindfulness-based interventions are popular treatments for obesity and MHDs, but little is known about the relationship between trait mindfulness and motive-based HPF eating. Therefore, a total of 927 young adults completed a survey that included the Palatable Eating Motives Scale-7 (which identifies Coping-, Reward enhancement-, Social-, and Conformity-eating), the Mindful Attention Awareness Scale, the Perceived Stress Scale, and demographic and body mass index (BMI) questions. An MHD questionnaire allowed a comparison of HPF eating between participants with and without various MHDs. Regressions revealed that Coping-eating was independently associated with lower mindfulness and also greater perceived stress, higher BMI, and female sex. Of these variables, only lower mindfulness was independently associated with Reward-, Social-, and Conformity-eating. Coping- and Reward-eating were more frequent in participants with versus without an anxiety disorder, depression, ADD/ADHD, and PTSD. Coping-eating was also more frequent in participants with body dysmorphic disorder. These findings warrant investigations in participants with clinically validated diagnoses for DSM-specific MHDs. Results from such investigations and the uncovered nature of associations between motive-specific HPF eating and trait mindfulness could provide novel targets to improve mindfulness-based interventions for obesity and MHDs
Three-Dimensional Reconstructions of Tadpole Chondrocrania from Histological Sections
Reconstructing three dimensional structures (3DR) from histological sections has always been difficult but is becoming more accessible with the assistance of digital imaging. We sought to assemble a low cost system using readily available hardware and software to generate 3DR for a study of tadpole chondrocrania. We found that a combination of RGB camera, stereomicroscope, and Apple Macintosh PowerPC computers running NIH Image, Object Image, Rotater. and SURFdriver software provided acceptable reconstructions. These are limited in quality primarily by the distortions arising from histological protocols rather than hardware or software
Grazing, motives to eat palatable foods, and fat and sugar consumption: an exploratory investigation
Period Change Rates of Large Magellanic Cloud Cepheids using MESA
Pulsating stars, such as Cepheids and RR Lyrae, offer us a window to measure
and study changes due to stellar evolution. In this work, we study the former
by calculating a set of evolutionary tracks of stars with an initial mass of 4
to 7 , varying the initial rotation rate and metallicity, using the
stellar evolution code Modules for Experiments in Stellar Astrophysics (MESA).
Using Radial Stellar Pulsations (RSP), a recently added functionality of MESA,
we obtained theoretical instability strip (IS) edges and linear periods for the
radial fundamental mode. Period-age, period-age-temperature, period-luminosity,
and period-luminosity-temperature relationships were derived for three rotation
rates and metallicities, showing a dependence on crossing number, position in
the IS, rotation, and metallicity. We calculated period change rates (PCRs)
based on the linear periods from RSP. We compared our models with literature
results using the Geneva code, and found large differences, as expected due to
the different implementations of rotation between codes. In addition, we
compared our theoretical PCRs with those measured in our recent work for Large
Magellanic Cloud Cepheids. We found good overall agreement, even though our
models do not reach the short-period regime exhibited by the empirical data.
Implementations of physical processes not yet included in our models, such as
pulsation-driven mass loss, an improved treatment of convection that may lead
to a better description of the instability strip edges, as well as
consideration of a wider initial mass range, could all help improve the
agreement with the observed PCRs.Comment: 19 pages, 17 figures. Accepted by MNRA
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