The primary photochemical processes of lignin-rich high-yield thermomechanical pulp (TMP) have been investigated with a view to understanding and ultimately preventing the yellowing (photoreversion) of such paper upon exposure to sunlight. This would enable their use in longer-life paper products and therefore represent large raw material and cost savings to the pulp and paper manufacturer.

No description available.

No description available.

No description available.

No description available.

Hannover, Universiẗat, Diss., 2005.

In the late 90s coconut farms in Mozambique were affected by a disease that made the coconut trees drop their leaves and die, the disease is called the coconut lethal yellowing disease (CLYD). It is known that planthoppers are spreading the disease. This thesis investigates if cultivation and farm related factors could have an impact on the risk of being infected by CLYD. With a sample of 534 farms from the two provinces Zambeze and Nampula a logistic regression model is estimated. The result shows that the only factor that has a significant effect of increasing the risk of getting infected by the disease is if farms had other palm species than coconut trees on the plantation. / I slutet av 90-talet drabbades många kokosnötsfarmer i Mocambique av en sjukdom som gjorde att träden började tappa sina löv och till slut dog. Denna sjukdom kallas för ”the coconut lethal yellowing disease” (CLYD). I dagsläget vet man att det är en specifik insekt som sprider denna sjukdom. Denna uppsats undersöker om det finns andra faktorer som kan påverka risken för koksnötsfarmer att drabbas av denna sjukdom, faktorer som är kopplade till farmerna och dess vegetation. Genom ett urval av 534 farmer från de två provinserna Zambezia och Nampula skattades en logistik regression. Resultatet visade att det enbart är en faktor, om plantagen innehåller andra palmsorter, som signifikant ökar risken för att en farm ska drabbas av CLYD.

NASCIMENTO, A.K.Q.do. Caracterização biológica e molecular de isolados e alternativas de controle do papaya lethal yellowing virus. 2010. 64 f. Dissertação (Mestrado em Fitotecnia)- Centro de Ciências Agrárias, Universidade Federal do Ceará, Fortaleza, 2010. / Submitted by Aline Nascimento (vieiraaline@yahoo.com.br) on 2013-04-29T18:44:12Z No. of bitstreams: 1 2010_Disser_akqnascimento.pdf: 677768 bytes, checksum: 787364fdf4fa3da04346c5fb4ce92bc7 (MD5) / Approved for entry into archive by Aline Nascimento(vieiraaline@yahoo.com.br) on 2013-04-29T20:25:58Z (GMT) No. of bitstreams: 1 2010_Disser_akqnascimento.pdf: 677768 bytes, checksum: 787364fdf4fa3da04346c5fb4ce92bc7 (MD5) / Made available in DSpace on 2013-04-29T20:25:58Z (GMT). No. of bitstreams: 1 2010_Disser_akqnascimento.pdf: 677768 bytes, checksum: 787364fdf4fa3da04346c5fb4ce92bc7 (MD5) Previous issue date: 2010 / Papaya (Carica papaya) is an important tropical fruit crop which production is increasing in irrigated areas of Northeast of Brazil. Lethal yellowing is a papaya disease caused by Papaya lethal yellowing virus (PLYV) that occurs only in the Northeast of Brazil. The virus symptoms begin with a progressive leaf yellowing in the third superior part of the plant canopy, which wilt and finally die. Greenish circular spots also appear on the fruits which turn yellowish when the fruits are ripping. The PLYV has isometric particles with ac. 30 nm in diameter, genomic ssRNA of ac. 1.6 x 106 Da and a coat protein composed of a single component of ac. 35 Da. Although no biological vector has been confirmed for the virus, it is spreading every year in the Northeast of Brazil, probably by infected young plants and contaminated tools. The virus can be transmitted through the soil, irrigated water, agriculture tools and contaminated hands. The present research had the following objectives: evaluate the possibility of the virus to be transmitted by seeds and aphids; evaluate its possibility to infect other plant species from the family Caricaceae; evaluate the effects of soilarization in the virus infectivity and analyze the molecular and biological variability among the virus isolates. In the aphid transmission studies, the virus was not transmitted by Aphis craccivora neither by A. gossypii in persistent and non-persistent manners. In the seed transmission experiments, the virus was not detected by indirect ELISA in a total of 1,680 seedlings originated from PLYV infect fruits. The PLYV infected the plant species Jacaratia heterophila, J. spinosa, Vasconcella quercifolia and V. monoica, confirming that its host range is probably restricted to Caricaceae species. The virus was inactivated in leaves and roots eradicated from infected plants when they were submitted to a solarization for a period of 12 days, but maintained its infectivity when the leaves and the roots were maintained without solarization at natural conditions for a period of 32 days. The use of extract from fruits of Caesalpinia ferrea inactivated PLYV when it was mixed with extract from infected plants, although the C. ferrea extract did not interfered with the virus infection when it was sprayed on the plant leaves before or after the virus inoculation. The PLYV obtained from different regions from the State of Ceará: PLYVFC (Fortaleza-Centro), PLYVFQ (Fortaleza – Edson Queiroz), PLYVH (Horizonte), PLYVLN (Limoeiro do Norte), PLYVM (Marco), PLYVMD (Marco – DIBAU), PLYVP (Paraipaba), PLYVQ (Quixeré) and PLYVBE (Boa Esperança- Quixeré) showed low molecular variability when compared by its nucleotide sequences involving part of the genes RpRd/CP. When compared with members from the genera Sobemovirus and Tombusvirus, the PLYV showed more similarity with members from the genus Sobemovirus. / O mamoeiro (Carica papaya) é uma importante fruteira tropical cuja produção vem crescendo no Nordeste do Brasil. Amarelo letal é uma moléstia do mamoeiro ocasionada pelo Papaya lethal yellowing virus (PLYV) que ocorrer somente Nordeste. Os sintomas ocasionados pelo PLYV têm início com um amarelecimento progressivo das folhas do no terço superior da copa, as quais murcham e morrem. Manchas circulares, inicialmente esverdeadas aparecem nos frutos as quais se tornam amareladas quando os frutos amadurecem. O PLYV possui partículas isométricas com 30 nm de diâmetros, genoma do tipo ssRNA de ac. 1,6 x 106 Da, com a capa protéica composta de uma única proteína de ac. 35 Da. Embora não exista confirmação da existência de um vetor biológico para o vírus, o mesmo está se disseminando rapidamente no Nordeste brasileiro, possivelmente por mudas de plantas infetadas e ferramentas contaminadas. O vírus pode ser transmitido através do solo, água de irrigação, ferramentas agrícolas e mãos contaminadas. A presente pesquisa teve como objetivos: avaliar a possibilidade do vírus ser transmitido por sementes e por afídeos; avaliar a possibilidade do PLYV infetar outras espécies da família Caricaceae; avaliar o efeito da solarização na inativação do vírus em restos de cultura e analisar a variabilidade molecular e biológica de isolados de PLYV. Nos ensaios de transmissão do vírus por afídeos, o mesmo não foi transmitido por Aphis craccivora e A. gossypii de forma persistente nem de forma não persistente. Nos experimentos de transmissão por sementes, o vírus não foi detectado por ELISA indireto em 1.680 plântulas originadas de sementes de frutos infetados com o PLYV. O PLYV infetou as espécies de Jacaratia heterophila, J. spinosa, Vasconcella quercifolia e V. monoica, confirmando que sua gama de hospedeiras está, provavelmente, restrita à família Caricaceae. O PLYV foi inativado em folhas e raízes de plantas infetadas e erradicadas, quando submetidas à solarização, por um período de 12 dias, enquanto que permaneceu ativo em folhas e raízes de plantas infetadas e erradicadas, mantidas sem solarização, até um período de 32 dias. O uso de extrato de jucazeiro (Caesalpinia ferrea) inativou o PLYV quando misturado ao extrato de plantas infetadas, porém não apresentou nenhum efeito no processo de infecção em plantas já inoculadas com PLYV e pulverizadas com extrato de jucazeiro e em plantas pulverizadas e em seguida inoculadas. Os isolados de PLYV obtidos de diferentes regiões do estado do Ceará: PLYVFC (Fortaleza-Centro), PLYVFQ (Fortaleza – Edson Queiroz), PLYVH (Horizonte), PLYVLN (Limoeiro do Norte), PLYVM (Marco), PLYVMD (Marco – DIBAU), PLYVP (Paraipaba), PLYVQ (Quixeré) e PLYVBE (Boa Esperança- Quixeré) apresentaram baixa variabilidade molecular, quando comparados através das seqüências nucleotídicas de parte dos genes RpRd/CP. Quando comparado com membros dos gêneros Sobemovirus e do Tombusvirus, o PLYV apresentou maior similaridade com vírus do gênero Sobemovirus.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O mamoeiro (Carica papaya) à uma importante fruteira tropical cuja produÃÃo vem crescendo no Nordeste do Brasil. Amarelo letal à uma molÃstia do mamoeiro ocasionada pelo Papaya lethal yellowing virus (PLYV) que ocorrer somente Nordeste. Os sintomas ocasionados pelo PLYV tÃm inÃcio com um amarelecimento progressivo das folhas do no terÃo superior da copa, as quais murcham e morrem. Manchas circulares, inicialmente esverdeadas aparecem nos frutos as quais se tornam amareladas quando os frutos amadurecem. O PLYV possui partÃculas isomÃtricas com 30 nm de diÃmetros, genoma do tipo ssRNA de ac. 1,6 x 106 Da, com a capa protÃica composta de uma Ãnica proteÃna de ac. 35 Da. Embora nÃo exista confirmaÃÃo da existÃncia de um vetor biolÃgico para o vÃrus, o mesmo està se disseminando rapidamente no Nordeste brasileiro, possivelmente por mudas de plantas infetadas e ferramentas contaminadas. O vÃrus pode ser transmitido atravÃs do solo, Ãgua de irrigaÃÃo, ferramentas agrÃcolas e mÃos contaminadas. A presente pesquisa teve como objetivos: avaliar a possibilidade do vÃrus ser transmitido por sementes e por afÃdeos; avaliar a possibilidade do PLYV infetar outras espÃcies da famÃlia Caricaceae; avaliar o efeito da solarizaÃÃo na inativaÃÃo do vÃrus em restos de cultura e analisar a variabilidade molecular e biolÃgica de isolados de PLYV. Nos ensaios de transmissÃo do vÃrus por afÃdeos, o mesmo nÃo foi transmitido por Aphis craccivora e A. gossypii de forma persistente nem de forma nÃo persistente. Nos experimentos de transmissÃo por sementes, o vÃrus nÃo foi detectado por ELISA indireto em 1.680 plÃntulas originadas de sementes de frutos infetados com o PLYV. O PLYV infetou as espÃcies de Jacaratia heterophila, J. spinosa, Vasconcella quercifolia e V. monoica, confirmando que sua gama de hospedeiras estÃ, provavelmente, restrita à famÃlia Caricaceae. O PLYV foi inativado em folhas e raÃzes de plantas infetadas e erradicadas, quando submetidas à solarizaÃÃo, por um perÃodo de 12 dias, enquanto que permaneceu ativo em folhas e raÃzes de plantas infetadas e erradicadas, mantidas sem solarizaÃÃo, atà um perÃodo de 32 dias. O uso de extrato de jucazeiro (Caesalpinia ferrea) inativou o PLYV quando misturado ao extrato de plantas infetadas, porÃm nÃo apresentou nenhum efeito no processo de infecÃÃo em plantas jà inoculadas com PLYV e pulverizadas com extrato de jucazeiro e em plantas pulverizadas e em seguida inoculadas. Os isolados de PLYV obtidos de diferentes regiÃes do estado do CearÃ: PLYVFC (Fortaleza-Centro), PLYVFQ (Fortaleza â Edson Queiroz), PLYVH (Horizonte), PLYVLN (Limoeiro do Norte), PLYVM (Marco), PLYVMD (Marco â DIBAU), PLYVP (Paraipaba), PLYVQ (QuixerÃ) e PLYVBE (Boa EsperanÃa- QuixerÃ) apresentaram baixa variabilidade molecular, quando comparados atravÃs das seqÃÃncias nucleotÃdicas de parte dos genes RpRd/CP. Quando comparado com membros dos gÃneros Sobemovirus e do Tombusvirus, o PLYV apresentou maior similaridade com vÃrus do gÃnero Sobemovirus / Papaya (Carica papaya) is an important tropical fruit crop which production is increasing in irrigated areas of Northeast of Brazil. Lethal yellowing is a papaya disease caused by Papaya lethal yellowing virus (PLYV) that occurs only in the Northeast of Brazil. The virus symptoms begin with a progressive leaf yellowing in the third superior part of the plant canopy, which wilt and finally die. Greenish circular spots also appear on the fruits which turn yellowish when the fruits are ripping. The PLYV has isometric particles with ac. 30 nm in diameter, genomic ssRNA of ac. 1.6 x 106 Da and a coat protein composed of a single component of ac. 35 Da. Although no biological vector has been confirmed for the virus, it is spreading every year in the Northeast of Brazil, probably by infected young plants and contaminated tools. The virus can be transmitted through the soil, irrigated water, agriculture tools and contaminated hands. The present research had the following objectives: evaluate the possibility of the virus to be transmitted by seeds and aphids; evaluate its possibility to infect other plant species from the family Caricaceae; evaluate the effects of soilarization in the virus infectivity and analyze the molecular and biological variability among the virus isolates. In the aphid transmission studies, the virus was not transmitted by Aphis craccivora neither by A. gossypii in persistent and non-persistent manners. In the seed transmission experiments, the virus was not detected by indirect ELISA in a total of 1,680 seedlings originated from PLYV infect fruits. The PLYV infected the plant species Jacaratia heterophila, J. spinosa, Vasconcella quercifolia and V. monoica, confirming that its host range is probably restricted to Caricaceae species. The virus was inactivated in leaves and roots eradicated from infected plants when they were submitted to a solarization for a period of 12 days, but maintained its infectivity when the leaves and the roots were maintained without solarization at natural conditions for a period of 32 days. The use of extract from fruits of Caesalpinia ferrea inactivated PLYV when it was mixed with extract from infected plants, although the C. ferrea extract did not interfered with the virus infection when it was sprayed on the plant leaves before or after the virus inoculation. The PLYV obtained from different regions from the State of CearÃ: PLYVFC (Fortaleza-Centro), PLYVFQ (Fortaleza â Edson Queiroz), PLYVH (Horizonte), PLYVLN (Limoeiro do Norte), PLYVM (Marco), PLYVMD (Marco â DIBAU), PLYVP (Paraipaba), PLYVQ (QuixerÃ) and PLYVBE (Boa EsperanÃa- QuixerÃ) showed low molecular variability when compared by its nucleotide sequences involving part of the genes RpRd/CP. When compared with members from the genera Sobemovirus and Tombusvirus, the PLYV showed more similarity with members from the genus Sobemovirus.

Coconuts are one of the most economically important plants in Mozambique, where millions of people depend on income from coconuts. The coconut lethal yellowing disease (CLYD) is a highly destructive disease that ever since the early 90’s causes coconut palms in Mozambique to stop producing fruit and leave the coconut farmers with only empty stems. This thesis examines the disease's effect on the farmers’ income, both from coconuts and other complementary sources, since the vendible harvest should decrease with the incidence of the disease. The method used is multivariate linear regression, where several income variables are used as dependent variables. Two models are created, one only interpreted for the sample of 488 observations and one aiming at generalizing the results. By this study, it cannot be confirmed that the incidence of CLYD has a significant effect on coconut farmers’ income. The results from the sample analysis do however show that the income is affected by the degree of the disease, which is an incentive for continued research in the field.