Adubação nitrogenada e idade de corte na produção de matéria seca do capim-elefante no Cerrado

Propôs-se, com este trabalho, avaliar o efeito da aplicação de N e da idade de corte na produção de biomassa e acúmulo de nitrogênio pelo capim-elefante. O experimento foi realizado com o capim-elefante cv. Paraíso, cultivado em um Latossolo Vermelho-Amarelo distrófico, município de Gurupi, TO, safra 2008/2009. Foram testadas quatro doses de N-uréia (0, 50, 100 e 150 kg ha-1) e três idades de corte do capim (120, 150 e 180 dias após o brotamento). Avaliou-se, em cada idade de corte, a produção de matéria seca da parte aérea (folhas e colmos) e o acúmulo de N na planta. A produção de matéria seca do capim-elefante aumentou com a adição de N porém o efeito foi maior para as plantas cortadas com 180 dias de idade. Encontrou-se um incremento linear na acumulação de matéria seca (R² = 0,75**) e na acumulação de N (R² = 0,96**), permitindo uma produtividade de 34 t ha-1 de matéria seca, que implicou em uma extração de N de 471 kg ha-1. A eficiência de utilização do N pela cultura variou com o aumento da idade da planta, o que significou maior quantidade de biomassa por unidade de N absorvido. O índice de eficiência mostra que o corte tardio pode favorecer a qualidade da biomassa para fins energéticos, por se tratar de um material mais fibroso.The objective of this study was to investigate the effect of the application of N fertilizer and the cutting age on the dry biomass production of elephant grass. The experiment was performed with the variety Paraíso and planted in a Ferralsol in 2008 in the district of Gurupi (State of Tocantins). Four different rates of urea application were tested (0, 50, 100 and 150 kg ha-1) and harvests were made at 120, 150 or 180 days after germination (DAG) of the setts. The dry matter and total N accumulation were evaluated. Dry matter production increased with dose of N, the greatest effect being observed at 180 DAG. There was a linear increase in dry matter (R² = 0.75**) and N accumulation (R² = 0.96**) permitting a productivity of 34 t ha-1 of dry matter and an accumulation of 471 kg N ha-1. The N utilization efficiency (biomass production per unit of applied N) increased with plant age. The higher efficiency of N use favored the quality of biomass production for energy production owing to the higher fibre content

Value resonance and value framing effects on voting intentions in direct-democratic campaigns

This study offers insights into how news media frames interact with existing value orientations in shaping voter preferences. It is assumed that a framing effect should be more pronounced when frames in the news resonate with people’s existing value predispositions. These assumptions were tested in a real-world setting of a political campaign dealing with the issue of naturalization of immigrants. Based on a data set in which the data of a two-wave panel survey were matched with content analytic data, the present research demonstrated frame-resonance effects for news reporting about the pro campaign. That is, framing the issue in terms of the notion that people should have the final say in naturalization procedures shaped voting preferences only for voters whose basic values of social order, tradition, and security (high authoritarians) were touched. In contrast, a main effect of the opponents’ framing in the news on voting preferences was found. Thus, the majority followed the framing of the opponents who put emphasis on a fair and pragmatic solution of the naturalization issue

Agenda building and setting in a referendum campaign: Investigating the flow of arguments among campaigners, the media, and the public

This study tests second-level agenda-building and -setting effects in the course of a referendum campaign. Personal standardized interviews with forty-seven different campaign managers and a content analysis of campaign material are linked to a content analysis of TV and newspaper coverage and a three-wave public opinion survey. The results demonstrate the dynamic flow of arguments in the agenda-building and -setting process: top-down from the campaigners to the news media and the public

Politische Kampagnen für Herz und Verstand : affektive und kognitive Einflüsse der Massenmedien auf politische Einstellungen

Welchen Einfluss haben Emotionen im Unterschied zu kognitiven Überzeugungen auf politische Einstellungen und Wahlentscheidungen? Welche Rolle spielt die Berichterstattung in Kampagnen dabei? Welche Rolle spielt die Motivation von Rezipienten zur Verarbeitung von Kampagneninformation? Diese Fragen werden theoretisch aufgearbeitet und am Beispiel empirischer Daten einer Inhaltsanalyse und einer Panelbefragung im Rahmen einer politischen Kampagne beantwortet. Die Studie zeigt, dass die politische Berichterstattung die Emotionen und Kognitionen von Rezipienten in Kampagnen beeinflusst und damit politische Einstellungen prägen kann. Gleichzeitig werden jedoch auch die Grenzen solcher Medienwirkungen deutlich: Derjenige Teil des Publikums, der die Kampagne weniger aufmerksam verfolgt, wird stärker kognitiv und affektiv in seiner politischen Einstellung durch die Kampagnenberichterstattung beeinflusst, als Rezipienten, die sich intensiver mit Medieninformationen auseinandersetzen

Reinforcing spirals of negative group-related affects and selective attention to advertising in a political campaign

The present study investigates self-reinforcing spirals processes between the negative affect toward asylum seekers and the attention to political advertising in a campaign dealing with the issue of the asylum law restriction. Based on data from a three-wave panel survey, the study found evidence of such reciprocal influences. Specifically, the initial attention to political advertising elicited negative affective reactions, such as fear or anxiety toward asylum seekers in the course of the campaign. At the same time, these affective reactions enhanced people’s attention to subsequent political ads. Not only do the findings indicate the presence of reinforcing spirals processes but also do the data suggest that the spirals process is mainly fueled by cues emanating from the political campaign

Media effects on racial attitudes: Evidence from two panel surveys in Germany

Various studies have found that portrayals of ethnic minorities in media programming affect racial attitudes and prejudice in the audience. However, studies investigating the long-term effects of media representations of minorities are scarce. The present study examines how frequency of exposure to different news genres affects the development of both negative and positive attitudes toward immigrants in Germany. Two panel studies from different periods showed that frequent exposure to news outlets that portray immigrants in a negative light (e.g., tabloid newspapers, news shows on commercial television) increased negative racial attitudes in the German public. By the same token, frequency of exposure to news that frames immigrants more positively (e.g., quality newspapers, news shows on public broadcasting) decreased racial prejudice over time