2,090 research outputs found
TN : TP ratio and planktivorous fish do not affect nutrient-chlorophyll relationships in shallow lakes
No full text1. In previous work, phytoplankton regulation in freshwater lakes has been associated with many factors. Among these, the ratio of total nitrogen to total phosphorus (TN : TP) has been widely proposed as an index to identify whether phytoplankton are N- or P-limited. From another point of view, it has been suggested that planktivorous fish can be used to control phytoplankton. 2. Large-scale investigations of phytoplankton biomass [measured as chlorophyll a, (chl-a)] were carried out in 45 mid-lower Yangtze shallow lakes to test hypotheses concerning nutrient limitation (assessed with TN : TP ratios) and phytoplankton control by planktivorous fish. 3. Regression analyses indicated that TP was the primary regulating factor and TN the second regulating factor for both annual and summer phytoplankton chl-a. In separate nutrient-chl-a regression analyses for lakes of different TN : TP ratios, TP was also superior to TN in predicting chl-a at all particular TN : TP ranges and over the entire TN : TP spectrum. Further analyses found that chl-a : TP was not influenced by TN : TP, while chl-a : TN was positively and highly correlated to TP : TN. 4. Based on these results, and others in the literature, we argue that the TN : TP ratio is inappropriate as an index to identify limiting nutrients. It is almost impossible to specify a 'cut-off' TN : TP ratio to identify a limiting nutrient for a multi-species community because optimal N : P ratios vary greatly among phytoplankton species. 5. Lakes with yields of planktivorous fish (silver and bighead carp, the species native to China) > 100 kg ha(-1) had significantly higher chl-a and lower Secchi depth than those with yields < 100 kg ha(-1). TP-chl-a and TP-Secchi depth relationships are not significantly different between lakes with yields > 100 kg ha(-1) or < 100 kg ha(-1). These results indicate that the fish failed to decrease chl-a yield or enhance Z(SD). Therefore, silver carp and bighead carp are not recommended as a biotic agent for phytoplankton control in lake management if the goal is to control the entire phytoplankton and to enhance water quality.1. In previous work, phytoplankton regulation in freshwater lakes has been associated with many factors. Among these, the ratio of total nitrogen to total phosphorus (TN : TP) has been widely proposed as an index to identify whether phytoplankton are N- or P-limited. From another point of view, it has been suggested that planktivorous fish can be used to control phytoplankton
M-commerce: estratégias para difusão e implantação
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção.O trabalho apresentado a seguir tem por objetivo estudar estratégias para a difusão do M-Commerce, uma variação do E-Commerce (comércio eletrônico) onde o comércio é feito usando aparelhos conectados a redes sem fio e, por isto mesmo, móveis, o que justifica o "M" da sigla. Neste trabalho primeiramente são lançadas as definições do comércio eletrônico, mantendo-se o escopo do trabalho no segmento Business-to-Consumer. Em seguida, o trabalho fala brevemente sobre a economia digital e o marketing digital. Logo após, as tecnologias que envolvem o M-Commerce são discutidas, se dividindo em três componentes básicos: tecnologias de comunicação (WAP, Bluetooth, redes sem fio por pacotes), tecnologias de troca de informação (linguagens) e tecnologias de identificação e localização do usuário. Após esta discussão, são apresentados produtos potenciais e o panorama tecnológico atual, no Brasil e no mundo. No capítulo seguinte fala-se da difusão de inovações, usando principalmente o modelo de Rogers (1995). Neste capítulo descreve-se os elementos que compõem a difusão de inovações (a inovação, os canais de comunicação, o tempo e o sistema social) e são levantados os fatores que devem ser levados em conta na difusão de uma nova tecnologia (econômicos, tecnológicos e culturais). Por fim, são levantadas possíveis construções estratégicas para a difusão do M-Commerce. Para este fim, é usado principalmente o modelo de construção de estratégias de Sawyer (1986), baseado nos três fundamentos de uma estratégia (produto, mercado e negócio), abordados à luz do M-Commerce e da difusão de inovações. Como resultado, chega-se às considerações mais importantes que devem ser tomadas para que o M-Commerce possa crescer e se difundir, bem como aos desafios que terá de enfrentar para que isto ocorra
A Critique of Foucault’s Conception and Predictions of the Author-Function
No full textIn this paper, we appraise the thoughts of Foucault on the relationship between the author, work, and text, and the future of that relationship. In Foucault’s view, the text points to an author who is anterior to it, but this relationship is more complex than ‘traditionally’ understood because of the asymmetrical relationship between the concepts of author/writer and text/work. Although the author-function entails a form of individualization of text and ideas, Foucault argues that this has varied across disciplines, cultures, and time. In any case, the author-function determines the process of authentication, mode of circulation, and valorization. From the analysis of the relationship between the author and text in the premodern and modern eras, Foucault extrapolates that in the postmodern era the author-function will be transformed and diminished because language assumes the dominant role of determining the form and content of viable discourse. Foucault’s conception of the author-function is post-modernist and consequently eschews the author-figure, grand narratives, progressive and systematic evaluation of texts, values and ideology, and temporality. However, contemporary trends in the understanding of the author-function do not fully bear out his predictions. Besides, intellectual property rights are more institutionalized and the boundary between authorized and unauthorized valorization and modification is intensely contested. The contestations are over valuable creations and, whether originating from an author or authors, this affirms the viability of projects such as Sage Philosophy. Key Words Author-function, work, text, discourse, postmodernism, valorizatio
Productivity of a breeding system with nelore catlle on the cerrados condition of central brazil
No full textFoi validado durante quatro anos um modelo simulado de cria e recria de animais Nelore a pasto, nos Cerrados do Centro—Oeste brasileiro. Novilhas tiveram taxa média de prenhez (TP) de 89% e vacas de 87%. Taxa de desmama foi 87% e de mortalidade de bezerros 6%. Ordem de parto (OP) teve efeito quadrático na TP (P<0,0001). Vacas primiparas (0P1) tiveram TP de 69% e OP5-0P8 90%. Condição corporal (CC) à desmama afetou a TP (P=0,0007). Vacas OP1 com CC 2,0 e 3,5 tiveram TP de 52,7 e 82,5%, respectivamente. Entre OP4-0P8 com CC 3,5 a TP foi 96%. OP teve efeito quadrático no intervalo de partos (IP; P<0,0001). Vacas OP1 tiveram IP de 392,10 ± 3,54 dias e OPs superiores 370 dias. Vacas OP1 desmamaram bezerros com 159,01 ± 2,30 kg e OP4 com 178,07 ± 3,44 kg (P<0,001). As novilhas acasalaram aos 776,04 ± 30,11 dias com peso vivo (PV) de 306,95 ± 32,79 kg. Novilhas prenhas foram 25,58 ± 9,97 dias mais velhas (P=0,0124) e 9,8 ± 7,04 kg mais pesadas (P=0,1683) do que as falhadas. A CC e PV médio geral das vacas foram 3,77 e 429 kg, respectivamente. Novilhos apresentaram PV de 366 kg aos 20/21 meses e condição de terminação em confinamento. A produtividade anual de PV do sistema foi 206,11 kg/ha. Vacas Nelore com CC maior que 3,0 apresentaram altos índices de produtividade. Novilhas Nelore iniciando a vida reprodutiva aos 24/26 meses de idade tiveram alta TP.A simulated mode! was validate for a breeding and rearing system under Cerrado condition of Central Brazil. Nelore cow's and heifer's pregnancy rate (TP) were 87 and 89%, respectively. The weaning rate mean was 87% and calf mortality 6%. Calving arder (OP) had quadratic response on TP (P<0,0001). First calving cows (OP1) had TP of 69% and cows of OP5 to OP8 of 90%. Body condition (CC) at weaning affected TP (P=0,0007). OP1 cows with CC of 2,0 and 3,5 had TP of 52,7 and 82,5%, respectively. For OP4 to OP8 cows with CC 3,5 TP was 96%. The OP showed quadratic response on calving interval (IP), (P<0,0001). OP1 cows had IP of 392,10 ± 3,54 days and cows with higher OPs 370 days. Calve's weaning weight was 159,01 ± 2,30 kg for OP1 cows and 178,07 ± 3,44 kg for OP4 cows (P<0,001). Heiferis live weight (PV) and age at breeding season were 306,95 ± 32,79 kg and 776,04 ± 30,11 days, respectively. Pregnant heifers were 25, 58 ± 9,97 days older (P=0,0124) and 9,8 ± 7,04 kg heaviest (P=0,1683) than no pregnant ones. The CC and PV cow's means were 3,77 and 429 kg, respectively. Steers 20/21 months old weighed 366 kg and had development to be finished at feed lot. The annual productivity of the system was 206,11 kg of PV per hectare. Nelore cows on tropical pasture condition with CC around 3.5 showed high productivity. Heifers 24/26 months old showed high TP
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No full textAccounting for centre-effects in multicentre trials with a binary outcome – when, why, and how?
No full textOpen Access Research article
Accounting for centre-effects in multicentre trials with a binary outcome – when, why, and how?
Brennan C Kahan
Correspondence: Brennan C Kahan [email protected]
Author Affiliations
Pragmatic Clinical Trials Unit, Queen Mary University of London, 58 Turner Street, London E1 2AB, UK
MRC Clinical Trials Unit at UCL, 125 Kingsway, London WC2B 6NH, UK
BMC Medical Research Methodology 2014, 14:20 doi:10.1186/1471-2288-14-20
The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1471-2288/14/20
Received: 5 July 2013
Accepted: 3 February 2014
Published: 10 February 2014
© 2014 Kahan; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.
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Abstract
Background
It is often desirable to account for centre-effects in the analysis of multicentre randomised trials, however it is unclear which analysis methods are best in trials with a binary outcome.
Methods
We compared the performance of four methods of analysis (fixed-effects models, random-effects models, generalised estimating equations (GEE), and Mantel-Haenszel) using a re-analysis of a previously reported randomised trial (MIST2) and a large simulation study.
Results
The re-analysis of MIST2 found that fixed-effects and Mantel-Haenszel led to many patients being dropped from the analysis due to over-stratification (up to 69% dropped for Mantel-Haenszel, and up to 33% dropped for fixed-effects). Conversely, random-effects and GEE included all patients in the analysis, however GEE did not reach convergence. Estimated treatment effects and p-values were highly variable across different analysis methods.
The simulation study found that most methods of analysis performed well with a small number of centres. With a large number of centres, fixed-effects led to biased estimates and inflated type I error rates in many situations, and Mantel-Haenszel lost power compared to other analysis methods in some situations. Conversely, both random-effects and GEE gave nominal type I error rates and good power across all scenarios, and were usually as good as or better than either fixed-effects or Mantel-Haenszel. However, this was only true for GEEs with non-robust standard errors (SEs); using a robust ‘sandwich’ estimator led to inflated type I error rates across most scenarios.
Conclusions
With a small number of centres, we recommend the use of fixed-effects, random-effects, or GEE with non-robust SEs. Random-effects and GEE with non-robust SEs should be used with a moderate or large number of centres
Pengaruh Pembelajaran Pengantar Acara Agama Hindu Kaharingan Terhadap Keterampilan Membuat Sarana Upacara Keagamaan Mahasiswa Prodi Pendidikan Agama Hindu IAHN TP Palangka Raya
No full textThis research is based on the problems that the author found in the Hindu religious education study program for the 2023/2024 academic year. Research found that students' skills, especially in making ceremonial facilities, can be said to be lacking. This can be seen from the fact that there are still many students who have not been able to make ceremonial facilities such as making ketupat, tawar containers, decorations in the lap for basarah, lack of interest in making ceremonial facilities, and there are still students who are not focused on the learning process so that in this case it requires more efforts to improve student skills in making ceremonial facilities. The purpose of this study is to find out whether there is an influence of learning the introduction of Hindu religious events on the skills of making religious ceremony facilities for students of the Hindu religious education study program of the Hindu Religious Institute of the State Tampung Penyang (IAHN TP) Palangka Raya.
This type of research uses a quantitative research approach, with survey methods and data collection methods used for observation, documentation, and questionnaires. Learning data was obtained from distributing questionnaires/questionnaires by distributing them to respondents whose number was already known, namely 52 respondents, while skill data was obtained from the final semester exam scores (UAS) of students in grades A and B in the even semester of the 2023/2024 academic year, the data was analyzed by simple regression using IBM Statistics for windows.
From the results of the research that has been carried out, the hypothesis in this study indicates that t count (0.017) < t table (1.675), it can be concluded that the results of the research and discussion in this study do not have an influence between the learning of the introduction of Hindu religious events in Kaharingan and the skills in making ceremonial facilities for students of the Hindu religious education study program class A and class B in the even semester of the 2023/2024 academic year and with a learning period In the high category there were 13 people with a percentage of 6.9%, in the medium category there were 37 with a percentage of 19.47% and in the low category there were 2 people with a percentage of 1.6% of the total 52 respondents
Correlação linear e espacial entre a produtividade de forragem, a porosidade total e a densidade do solo de Pereira Barreto (SP) Linear and spatial correlations between forage yield, total porosity and bulk density in Pereira Barreto, Brazil
No full textEm relação aos sistemas de manejo adotados pelo homem, a porosidade total e a densidade do solo são atributos ativamente alterados, refletindo decisivamente sobre a produtividade vegetal agrícola. No ano agrícola de 2005, na Fazenda Bonança, no município de Pereira Barreto, Estado de São Paulo, Brasil, foram analisadas a produtividade de forragem do milho outonal (MSF) no sistema plantio direto irrigado, a porosidade total (PT) e a densidade do solo (DS) em profundidade, em um Latossolo Vermelho distrófico. O objetivo foi estudar a variabilidade e as correlações lineares e espaciais entre os atributos da planta e do solo, visando selecionar um indicador da qualidade física do solo de boa representatividade para produtividade da forragem. Foi instalada a malha geoestatística, para coleta de dados do solo e planta, contendo 125 pontos amostrais, numa área de 2.500 m². Os atributos estudados, além de não terem variado aleatoriamente, apresentaram variabilidade dos dados entre média e baixa e seguiram padrões espaciais bem definidos, com alcance entre 6,8 e 23,7 m. Por sua vez, a correlação linear entre o atributo da planta e os do solo, em razão do elevado número de observações, foi baixa. As observações de melhor correlação com a MSF foram a DS1 e a PT1. Entretanto, do ponto de vista espacial, houve excelente correlação inversa entre a MSF e a DS1, assim como entre a DS1 e a PT1. Nos sítios onde a DS1 aumentou (1,45-1,64 kg dm-3) a MSF variou entre 11.653 e 14.552 kg ha-1; já naqueles onde diminuiu (1,35-1,45 kg dm-3) a MSF, ficou entre 14.552 e 17.450 kg ha-1. Portanto, a densidade global, avaliada na camada de 0-0,10 m (DS1), apresentou-se como satisfatório indicador da qualidade física do solo de Pereira Barreto (SP), quando destinado à produtividade de forragem do milho outonal.Total porosity and bulk density are strongly affected by soil management, which is reflects directly in agricultural productivity. In 2005, plant attributes were analyzed in an irrigated fall corn crop under no-tillage besides some soil characteristics (total porosity-TP and bulk density-BD), in a Haplic Acrustox on the Fazenda Bonança (Dahma Agricultural Company) in Pereira Barreto County, Sao Paulo State, Brazil (20 ° 40 ' 12 '' latitude S; 51 ° 01 '50 '' longitude W). The purpose of the study was to evaluate the variability, and linear and spatial correlations among the attributes (plant and soil) in order to identify an indicator of soil physical quality for corn forage productivity (CPF) . A geostatistical grid was installed to collect soil and plant data, with 125 sample points, over an area of 2.500 m². The studied attributes did not vary randomly and the variability was medium to low, with well defined patterns. The spatial range varied between 6.8 and 23.7 m. On the other hand, the linear correlations between the CPF with the soil attributes (TP and BD) were low due to the high data number. BD1 and TP1 were best correlated with the CPF. However, concerning the spatial variability, the inverse correlations between CPF and BD1, as well as between BD1 and TP1 were excellent. The BD1 increased (1.45-1.64 kg dm-3) when the CPF varied from 11.653 to14.552 kg ha-1. At the sites where bulk density decreased (1.35-1.45 kg dm-3) the CPF varied from 14.552 to17.450 kg ha-1. Thus, the bulk density in the 0-0.10 m soil layer proved to be a satisfactory index of the soil physical quality regarding forage yield of fall corn
ISC/OSI Journal Authors Survey Report
No full textOn behalf of the Joint Information Systems Committee (JISC) and the Open Society Institute (OSI) a survey of journal authors has been carried out by Key Perspectives Ltd. The terms of reference were to poll a cohort of authors who had published on an open access basis and another cohort of authors who had published their work in conventional journals without making the article available on open access. The survey’s aims were to investigate the authors’ awareness of new open access possibilities, the ease of identification of and submission to open access outlets, their experiences of publishing their work in this way, their concerns about any implications open access publishing may have upon their careers, and the reasons why (or not) they chose to publish through an open access outlet
Estrutura e composição em fisionomias campestres setentrionais do Sul do Brasil
No full textTo contribute to the understanding of grassland formations in the southern Brazilian plateau, a floristic and structural survey was carried out in communities in its northern region. This region is characterized by a climate regime of transition between temperate and subtropical, within the phytogeographic zone called Campos Gerais. The study was carried out in grassland communities in the Guartelá State Park (Tibagi, Paraná State, Brazil - 24º39’10” S and 50º15’25” W), with the allocation of 90 sample units of 1 m2, distributed in 30 plots in the dry grassland (CS), 30 in rocky outcrops grassland (CR) and 30 in a wet grassland (CU). A total of 128 species and 28 families were found, with the occurrence of 66 species in CS, 55 in CR, and 64 in CU. Although the number of species sampled was higher in CS, there was no significant difference between grasslands for richness and diversity. Asteraceae (28 species), Poaceae (24), Melastomataceae (13), and Cyperaceae (11) were the families sampled with the highest species richness, a common pattern in grassland areas of the Mata Atlantica and Cerrado biomes. Few species were high frequency and coverage in the communities (mainly grasses) among several low biomass and low-frequency species. In addition, a marked zonation of vegetation was observed due to topographic and edaphic variations, since the greatest similarity was between CS and CR (54.54%) and dissimilarity between CR and UC (21.84%). Despite this, 10% of the species were found in common for CS, CU, and CR, an index higher than that found in studies carried out in the region. Floristic and structural differences in local and regional communities reinforce the need for further studies on the plateaus of southern Brazil for a more detailed understanding of this vegetation since its complexity is little known and the strong anthropic pressure has significantly affected its area of occurrence.Con el objetivo de contribuir a la comprensión de los pastizales naturales en la meseta sur de Brasil, se realizó un levantamiento florístico y estructural en comunidades de la parte norte de la región fitogeográfica Campos Gerais de Paraná, caracterizado por un clima de transición entre templado y subtropical. El estudio se realizó en tres fisonomías de pastizales naturales encontradas en el Parque Estatal Guartelá (Tibagi, PR, Brasil - 24º39’10” S y 50º15’25” O), con la distribución de 90 cuadrados de 1 m2: 30 en el pastizal seco (CS), 30 en pastizal rocosos (CR) y 30 en un pastizal húmedo (CU). Se encontraron un total de 128 especies y 28 familias, con ocurrencia de 66 especies en CS, 55 en CR y 64 en CU. A pesar del mayor número de especies en CS, no se observaron diferencias significativas en riqueza y diversidad entre los pastizales. La mayor riqueza de especies muestreadas fueron Asteraceae (28 especies), Poaceae (24), Melastomataceae (13) y Cyperaceae (11), un patrón común en las áreas de pastizales de los biomas Mata Atlântica y Cerrado. Pocas especies tuvieron alta frecuencia y cobertura en las comunidades, especialmente gramíneas, intercaladas con un alto número de espécies de baja frecuencia y biomasa. Además, se observó una marcada zonificación de la vegetación por las variaciones edáficas, ya que la mayor similitud se presentó entre CS y CR (54,54 %) y la disimilitud entre CR y CU (21,84 %). A pesar de eso, 10% de las especies se encontraron en común para CS, CU y CR, tasa superior a la encontrada en estudios en la región. Las diferencias florísticas y estructurales en las comunidades locales y regionales refuerzan la necesidad de más estudios en las mesetas del sur de Brasil para una comprensión más detallada de los pastizales naturales, ya que su complejidad es poco conocida y la fuerte presión antrópica ha reducido considerablemente su área de ocurrencia.Com objetivo de contribuir para o entendimento das formações campestres no planalto meridional brasileiro, realizou-se um levantamento florístico e estrutural em comunidades na parte norte da região fitogeográfica dos Campos Gerais do Paraná, sob um regime climático de transição entre temperado e subtropical. O estudo foi realizado em três fisionomias encontradas no Parque Estadual do Guartelá (Tibagi, PR) (24º39’10” S e 50º15’25” W), com a alocação de 90 unidades amostrais de 1 m2, distribuídas em 30 parcelas em campo seco (CS), 30 em campo com afloramentos rochosos (CR) e 30 em campo úmido (CU). Foram determinadas 128 espécies pertencentes a 28 famílias, com ocorrência de 66 espécies no CS, 55 no CR e 64 para o CU. Apesar do CS apresentar o maior número de espécies não foram observadas diferenças significativas de riqueza e diversidade entre as três fisionomias. A maior riqueza de espécies foi amostrada em Asteraceae (28 espécies), Poaceae (24), Melastomataceae (13) e Cyperaceae (11), padrão comum em áreas campestres dos Biomas Mata Atlântica e Cerrado. Poucas espécies apresentaram alta frequência e cobertura nas comunidades, especialmente gramíneas, entremeadas a um número alto de espécies de baixa frequência e biomassa. Além disso, observou-se uma marcante zonação da vegetação, ditada pelas variações topoedáficas, já que a maior similaridade ocorreu entre CS e CR (54,54%) e dissimilaridade entre CR e CU (21,84%). Apesar disso, foram encontradas 10% de espécies comuns a todas as fisionomias, índice superior ao encontrado em estudos na região. Diferenças florísticas e estruturais das comunidades locais e regionais reforçam a necessidade de mais estudos sobre os campos planálticos do Sul do Brasil para sua compreensão mais detalhada, já que sua complexidade é pouco conhecida e a forte pressão antrópica tem reduzido significativamente sua área de ocorrência
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