• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 139
  • 131
  • 24
  • 20
  • 17
  • 9
  • 8
  • 6
  • 4
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 423
  • 145
  • 116
  • 76
  • 65
  • 63
  • 41
  • 38
  • 38
  • 36
  • 24
  • 24
  • 23
  • 22
  • 22
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Human bitterness detection thresholds of hop acids in beer and honey /

Kolpin, Kathryn M. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 80-84). Also available on the World Wide Web.
32

Evaluating cape honey bee sperm quality and the in vitro effect of miticides on sperm functionality and structure

Murray, Janice Faith January 2021 (has links)
Magister Scientiae (Medical Bioscience) - MSc(MBS) / Apis mellifera (honey bees) are essential pollinators and thus considered a keystone species. Reproductive success is therefore important to the survival of the species, with drone sperm quality playing a vital role in fertilization success and colony health. Drone sperm quality is determined by multiple aspects including both structural and functional parameters. Particularly, motility, a functional parameter of sperm, plays an important role in reproductive success by determining the ability of sperm to move in the reproductive tract of the queen and to participate in fertilization. However, for the South African honey bee subspecies, the Cape honey bee (Apis mellifera capensis Escholtz), data on sperm quality parameters, are lacking. / 2023
33

Do the diversity of plants honey bees pollinate change over summer? : A study of the diversity of plant DNA found in honey over a summer

Lundberg, Eli January 2024 (has links)
The honey bee (Apis mellifera) is important both ecologically, as a generalist pollinator, and economically by pollinating our crops and producing honey. Honey bees use plants for foraging for pollen and nectar, which together constitute their entire diet. Yet, as flowering times of plants vary during the summer, so do the floral resources available. Honey bees are known to be selective for their food sources. Thus, their specificity in plant choices could vary according to the availability of flower sources, showing a differing usage of plant diversity in different timepoints. Alternatively, the honey bees selectivity to fulfill their nutrient needs could lead to a constant usage of diversity. The taxonomic origin of the plant DNA found in honey can be identified and used to investigate the plant taxa the bees have collected nectar and pollen from. This study asks whether the diversity of plants which honey bees use varies during summer (June, July, and August). I used two diversity indices as response variables: 1) the Shannon-Wiener diversity index and 2) the number of plant genera identified in the DNA in the honey. I used data gathered from 41 hives from 14 Finnish beekeepers. An ANOVA test revealed no significant difference among the three timepoints in either response variable, indicating honey bees select a constant diversity of plants throughout the season. The result suggest that different plants can fulfill honey bees’ requirements at different parts of the summer. Honey bees are generalists, but selective, producing a relatively constant usage of plants throughout the season.
34

Skirtingų medaus rūšių kokybės rodiklių vertinimas Lietuvos gyventojų tarpe / Assesment of quality indicators of different kinds of honey among lithuania citizens

Klimaitė, Vaida 18 June 2014 (has links)
Darbo struktūra: darbo apimtis 44 puslapiai, literatūros sąraše 30 šaltinių. Darbe yra 17 lentelių, 12 paveikslų ir priedas. Darbo tikslas: įvertinti Lietuvos gyventojų nuomonę apie skirtingų medaus rūšių kokybę. Darbo uždaviniai: atlikti vartotojų apklausą, apie medaus pasirinkimą Lietuvos gyventojų tarpe; Įvertinti vartotojų žinias apie medaus kokybę; Įvertinti medaus kokybės įtaką sveikatai; Nustatyti reikšmingus ryšius tarp tirtų rodiklių. Darbe analizuojama pagrindinės Lietuviško medaus rūšys, sudėtis, kokybė, įtaka sveikatai. Gauti rezultatai: atlikus apklausą nustatyta, kad medaus vartojimas statistiškai reikšmingai skiriasi tik tarp socialinės padėties grupės vartotojų. Vertinant respondentų pasiskirstymą renkantis medaus rūšis, mėgstamiausia laikoma liepų ir pievų medus. Statistiškai dažniausiai vartotojai pirmenybę teikia natūraliam medui, kurį būtinybę vartoti laiko daugiau nei trečdalis respondentų. Medų respondentai statistiškai reikšmingai vartoja kaip vaistą. Atliktos apklausos rezultatai parodė, kad vartotojai didelį dėmesį skiria medaus kokybei. Statistiškai reikšminga respondentai laiko pirkimo vietą, patikimiausia išlieka bitininko namai. Svarbiausiu veiksniu renkantis produktą, vartotojai nurodo kokybę, kuri turi teigiamą poveikį sveikatai. Respondentų nuomone, medaus kokybę lemia tokie veiksniai, kaip vietovė, bitės, meteorologinės sąlygos. / Structure: the volume is 46 pages,. The work contains 17 tables, 12 figures and appendix. The objective of this work.: evaluate the opinion of the Lithuanian population about different types of honey quality. The tasks of this work: conducting a survey of consumers of honey Lithuania choice among the population; Assess consumers' knowledge about the quality of honey; To evaluate the quality of the product on health; Identify significant relationships between the studied parameters. Results: The survey found that honey consumption significantly differed only between the social status of the group of users. Assessing the distribution of respondents in choosing the type of honey, lime and meadow was considered as favorites. Moreover, statistical analysis shoved that consumers prefer natural honey and one third of the respondents feel the need to consume it. Often respondents consume honey as medicine The result showed that consumers pay a lot of attention to honey quality. Purchase place was statistically significant, were the most reliable is beekeeper house. The most important factor in choosing a product is quality, which has a positive effect on health. According to the respondents, the quality of honey is determined by such factors as location, bees, meteorological conditions.
35

An investigation of the chemical constituents of honey locust, Gleditsia triacanthos L., as phagostimulants for larvae of the mimosa webworm, Homadaula albizziae Clarke /

Peacock, John William January 1967 (has links)
No description available.
36

Bee botany in Tanganyika

Smith, Francis G. January 1956 (has links)
No description available.
37

Desenvolvimento e otimização de métodos analíticos com nanopartículas para a avaliação de adulteração ou contaminação de alimentos /

Bittar, Dayana Borges. January 2017 (has links)
Orientadora: Helena Redigolo Pezza / Banca: José Anchieta Gomes Neto / Banca: Eny Maria Viera / Banca: Luciana Polese / Banca: Adriana Vitorino Rossi / Resumo: Neste trabalho, desenvolvimento e otimização de métodos foram propostos utilizando nanopartículas metálicas a fim de aumentar a sensibilidade desses métodos e detectar contaminantes/adulterantes em matrizes alimentares complexas como leite e mel. Em um primeiro momento, um método de detecção colorimétrico baseado em nanopartículas de prata foi desenvolvido para a determinação da melamina no leite. As nanopartículas de prata foram sintetizadas sem uso de qualquer agente estabilizante, utilizando borohidreto de sódio como agente redutor. A otimização das variáveis experimentais para a formação das nanopartículas foi realizada utilizando o planejamento fatorial, resultando em nanopartículas de prata coloidal estável com um diâmetro médio de 14,0 ± 2,7 nm. As medidas espectrofotométricas realizadas a 475 nm mostraram uma faixa linear de 0,033-1,50 mg L-1 de melamina (r = 0,999), com limites de detecção e quantificação de 0,009 e 0,031 mg L-1, respectivamente. O método proposto forneceu detecção altamente sensível de melamina no leite. Em um segundo momento, um método sensível, rápido e robusto baseado no uso de nanopartículas de prata isentas de estabilizantes foi desenvolvido para a detecção de chumbo em mel. As nanopartículas de prata foram sintetizadas sem o uso de qualquer estabilizante, utilizando-se como precursores nitrato de prata e borohidreto de sódio; este último como agente redutor. A otimização das variáveis experimentais (AgNO3 e NaBH4) para a formação das nanopartí... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work, development and optimization of methods were proposed using metallic nanoparticles in order to increase the sensitivity of these methods and detect contaminants / adulterants in complex food matrices such as milk and honey. In a first step, a colorimetric detection method based on silver nanoparticles was developed for the determination of melamine in milk. Silver nanoparticles were synthesized without the use of any stabilizing agent, using sodium borohydride as a reducing agent. The optimization of experimental variables for nanoparticle formation was performed using factorial design, resulting in stable colloidal silver nanoparticles with a mean diameter of 14.0 ± 2.7 nm. The spectrophotometric measurements performed at 475 nm showed a linear range of 0.033-1.50 mg L-1 melamine (r = 0.999), with detection limits (LOD) and quantification (LOQ) of 0.009 and 0.031 mg L-1, respectively. The proposed method provided sensitive detection and quantification of melamine in milk. In a second step, a sensitive, rapid and robust method based on the use of stabilizerfree silver nanoparticles was developed for the detection and quantification of lead in honey samples. Silver nanoparticles were synthesized without the use of any stabilizer, using silver nitrate and sodium borohydride as precursors; the latter as a reducing agent. The optimization of the experimental variables (AgNO3 and NaBH4) for the formation of the nanoparticles was carried out using different volumes of these solutions. Spectrophotometric measurements at 393 nm were performed showing a linear working range between 0.0500-0.167 mg L-1 lead (r = 0.994), with LOD and LOQ of 0.0135 and 0.0451 mg L-1, respectively. The proposed method provided sensitive detection for lead in honey samples. In the third step, the combination in the same analysis of multiple... (Full abstract, click on electronic access below) / Doutor
38

Desenvolvimento de um método limpo para análise de 5-hidroximetil-2furfuraldeído em mel /

Castoldi, Karine. January 2014 (has links)
Orientador: Helena Redigolo Pezza / Co-orientador: Leonardo Pezza / Banca: José Anchieta Gomes Neto / Banca: Matthieu Tubino / Resumo: Um dos indicadores de qualidade do mel é o 5-hidroximetil-2-furfural (HMF). O HMF é produzido pelo aquecimento e envelhecimento do mel. A Comissão Internacional do Mel recomenda três métodos para a determinação do HMF em mel, o método de Winkler, o método de White e a determinação por CLAE. O método de Winkler utiliza a substância carcinogênica p-toluidina, a qual não está de acordo com os princípios da Química Verde. O presente estudo propôs para a determinação de HMF em mel, um método por análise por injeção em fluxo (FIA) usando o método de Winkler modificado, substituindo a p-toluidina por ácido p-aminobenzóico. A faixa linear foi de 1,00 a 40,0 mg L-1, o limite de detecção (LD) foi de 0,43 mg L-1 e o limite de quantificação 1,32 mg L-1. O método é eficiente e mais ambientalmente amigável na análise de HMF em mel. / Abstract:One of the quality indicator for honey is 5-hydroxymethyl-2-furfural (HMF). The HMF is product by heating and aging of honey. The International Honey Commission recommends three methods for the determination of HMF in honey, the Winkler method, the White method, and determination by HPLC. The Winkler method uses the carcinogenic substance p-toluidine, which is not in agreement with the principles of Green Chemistry. The present study proposed for determination of HMF in honey, a flow injection analysis (FIA) method using a modified method of Winkler, replacing p-toluidine for p-aminobenzoic acid. The linear range was 1.00 to 40.0 mg L-1, the limit of detection (LD) was 0.43 mg L-1 and the limit of quantification (LQ) was 1.32 mg L-1. The method is efficient and most environmentally friendly in the analysis of HMF in honey. / Mestre
39

The Sensitivity of Adenovirus and Herpes simplex virus to Honey

Littlejohn, Emma Sophie Vout January 2009 (has links)
Honey has been used for centuries as a medicine to treat various ailments and infections. A large amount of research has established that honey has potent antibacterial activity. However, the sensitivity to honey of viral species that cause infections has been studied in only a small number of cases. The aim of this study was to obtain data to clarify and extend knowledge obtained from these previous studies of honey's antiviral activity, and especially study those viruses that cause localised infections which have limited or no therapy available, which are suitable to treatment with topically applied honey. The susceptible A549 cell line and viral isolates of Adenovirus serotypes 1, 3, and 8, and Herpes simplex virus serotypes 1 and 2, were provided by the Waikato Hospital Virology Laboratory. A number of types of honey were investigated from a range of sources: Manuka honey with high concentrations of methylglyoxal, unique manuka factor activity, and phenolics, Honeydew and Rewarewa honeys which have high antioxidant activity, and Ling Heather honey which is high in phenolic compounds. These honeys were selected due to their range of characteristic activities in order to make comparisons with antiviral activity. A variety of tests using cell culture were developed to evaluate the sensitivity of the viruses to whole honey. Each test scored and monitored the development of morphological changes to the cells, to observe whether the honey treatment can prevent the development of these changes known as viral cytopathic effect. These included tests for: protection, in which the cells were pre-treated with, and iii incubated either with or without honey; prevention, where honey was used to treat infected cells, and in plaque reduction assays, to examine whether it can reduce the resultant number of plaques; and neutralisation, in which the virus was directly exposed to the honey for a defined period. It was found with each type of test using cell culture that many of the honeys studied can lower the severity of viral cytopathic effect or delay its onset compared with the development observed with virus that was not treated with honey. This can suggest that the antiviral activity may be a feature of more than one type of honey. In general the antiviral effect increased with the concentration of honey and time the virus was exposed to it. Manuka honey M116 at a concentration of 10% was effective in preventing the development of viral cytopathic effect of each of virus, after the viruses at concentrations in excess of the tissue culture infectious dose had been exposed to the honey for 8 hours. Enzyme-linked immunosorbant assays were used to measure the effect the successful treatments found in the extended neutralisation experiments had on viral surface proteins necessary for viral entry into the cells. The results using this technique suggested that there was very little virus present in the samples that had been treated with honey and with the untreated virus. Therefore it could not be shown whether the honey was acting via this mechanism. It is concluded from the findings in this study that honey is likely to be an effective antiviral treatment for the therapy of localised viral infections, this needs to be verified by clinical trials.
40

Honey bee gene regulation and transcriptional effects of a pheromone and a parasite

Butler, Lara Elizabeth 15 May 2009 (has links)
The European honey bee, Apis mellifera, is a primarily beneficial insect for mankind. It has been utilized by humans for thousands of years for the products and services it provides. Crop pollination and honey production are two of the most economically beneficial activities of the honey bee. Though they have been important for many centuries and immeasurable amounts of effort have been expended investigating the methods and means to harness their natural abilities, a far lesser amount of attention has been directed towards exploring their molecular makeup. These experiments involve identifying modification of gene transcription as a result of exposure to a pheromone or a parasite. This data will provide information on the general types of transcripts involved in the biochemical response of the honey bee to the two stimuli and will also provide specific candidates for further investigation of their potential role in downstream behavioral events.

Page generated in 0.0434 seconds