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1.
Article in English | WPRIM (Western Pacific) | ID: wpr-962300

ABSTRACT

Objective@#This pilot study investigated whether serum B-type Natriuretic Peptide (BNP), bioelectrical impedance analysis (BIA), and left ventricular end-diastolic diameter (LVEDD) can be used to predict fluid overload and clinical outcomes in pediatric sepsis. @*Methods@#Pediatric sepsis patients were enrolled. BNP, BIA, and LVEDD were obtained on admission and on Day 3. Diagnostic performances of BNP, BIA, LVEDD and correlation with fluid status were obtained.@*Results@#Twenty-two patients were enrolled. Day 3 BNP was higher in non-survivors (9241 vs. 682.2 pg/mL, p=0.04) and day 3 LVEDD Z-score was lower in non-survivors (-3.51 vs. -0.01, p=0.023). There was no difference in the fluid balance between survivors and non-survivors. Admission BNP >670.34pg/mL predicted vasopressor use with a sensitivity of 85.71% and specificity of 86.67% while ΔBNP>5388.13pg/mL predicted mortality with 100% sensitivity. Day 3 LVEDD <22mm predicted mortality with a sensitivity of 94.74%. Cumulative fluid balance was strongly correlated with BIA and LVEDD (r=0.65, p=0.001; r=0.74, p<0.001 respectively). The median length of stay in hospital days for non-survivors was not significantly different from survivors (4 [1-12] vs. 8 [6-12] days,p=0.21). @*Conclusion@#Rise in BNP levels appear to be independent of fluid status and is a good predictor of mortality, vasopressor, and mechanical ventilator use but not of length of hospital stay. LVEDD and BIA are good estimates of cumulative fluid balance but not as predictors of mortality, vasopressor, mechanical ventilator use, and length of hospital stay. Significance of the outcomes of the study was limited due to the small sample size.


Subject(s)
Natriuretic Peptide, Brain , Echocardiography
2.
Aust Vet J ; 99(11): 495-501, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34389973

ABSTRACT

A sustainable workforce is important for the veterinary profession to meet the demands of society. To maintain a sustainable workforce, it has been recommended to retain veterinary clinicians. However, there seems to be an increasing issue with retention of veterinarians in clinical practice. In the following study, the researchers sought to understand the associations between demographic and work-related factors and attrition of veterinarians from clinical practice. Responses to an online cross-sectional survey of 881 current and former Australian veterinary clinicians were analysed. A logistic regression model was used to identify and describe associations between attrition from veterinary clinical practice and salary, working hours, role in practice, years of experience, field of work, interaction with regulatory authorities, region of work and on-call duties. Lower salary, longer working hours, having on-call duties and having worked in both rural and metropolitan regions were found to significantly (P < 0.05) increase the likelihood of leaving clinical practice. The results may inform intervention strategies to assist the industry to retain veterinarians in clinical practice.


Subject(s)
Veterinarians , Veterinary Medicine , Animals , Australia , Cross-Sectional Studies , Humans , Risk Factors , Salaries and Fringe Benefits , Surveys and Questionnaires
3.
Aust Vet J ; 99(8): 334-343, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34002368

ABSTRACT

This study set out to explore how euthanasia decision-making for animals was taught to students in eight Australasian veterinary schools. A questionnaire-style interview guide was used by a representative at each university to interview educators. Educators were interviewed about their teaching of euthanasia decision-making for four categories of animals: livestock, equine, companion and avian/wildlife. Using thematic analysis, the terms provided by participants to describe how (mode of teaching) and what (specific content) they taught to students were categorised. Information about content was categorised into human-centred factors that influence decision-making, and animal-based indicators used to directly inform decision-making. All eight representatives reported some teaching relevant to euthanasia decision-making at their university for livestock, companion animal and avian/wildlife. One representative reported no such teaching for equid animals at their university. Observation of a euthanasia case was rarely reported as a teaching method. Five universities reported multiple modes of teaching relevant information, while two universities made use of modalities that could be described as opportunistic teaching (e.g., 'Discussion of clinical cases'). Factors taught at most universities included financial considerations, and that it is the owner's decision to make, while animal-based indicators taught included QoL/animal welfare, prognosis and behaviour change. Overall, most universities used a variety of methods to cover relevant material, usually including lectures and several other approaches for all animal types. However, because two universities relied on presentation of clinical cases, not all students at these veterinary schools will be exposed to make, or assist in making, euthanasia decisions.


Subject(s)
Education, Veterinary , Animals , Animals, Wild , Euthanasia, Animal , Horses , Humans , Quality of Life , Students
4.
J Appl Anim Welf Sci ; 24(3): 215-237, 2021.
Article in English | MEDLINE | ID: mdl-31992080

ABSTRACT

The objective of this study was to investigate the animal welfare issues considered the most important by companion animal veterinarians worldwide. For this purpose, a global survey of several potential animal welfare issues was distributed via SurveyMonkey® in multiple languages. The distribution of survey responses differed by region. The main animal welfare concern reported worldwide was obesity, although there were differences across regions, possibly due to cultural and socioeconomic factors. Anthropomorphism (attributing human qualities or characteristics to an animal) was an issue in western countries but less so in Asia, Africa, and Oceania. There were significant differences between Asia and Europe, Africa, and Oceania in the importance and prevalence of convenience euthanasia. There were also age and sex differences in participant responses, with older veterinarians reporting fewer welfare problems than younger veterinarians, and female veterinarians reporting more welfare issues than their male counterparts.


Subject(s)
Animal Welfare , Attitude of Health Personnel/ethnology , Veterinarians/psychology , Age Factors , Animals , Education, Veterinary , Euthanasia, Animal , Female , Humans , Male , Obesity/veterinary , Sex Factors , Surveys and Questionnaires
5.
Aust Vet J ; 98(8): 356-363, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32458445

ABSTRACT

OBJECTIVE: Veterinarians have an important role in supporting and understanding their clients' grief. Veterinary schools have a duty to teach students how best to manage grief - both that of the students/future veterinarians and the clients. This study explores how grief management, associated with ending the life of an animal, was taught to students in eight Australasian veterinary schools. METHODS: A questionnaire-style interview guide was used by a representative at each university to conduct structured interviews with educators in a snowball sampling approach. Educators were interviewed about the teaching of grief management for four categories of animals: livestock, equine, companion and avian/wildlife. The terms used by participants to describe what they taught were grouped into common themes. Teaching was defined by individual participants and included structured and unstructured approaches. The stage in the degree (preclinical or clinical years) that grief management was taught in the veterinary curriculum and by whom (e.g. clinicians or psychologists) is also described. RESULTS: Grief management was taught more in preclinical than clinical years. However, due to how grief was characterised, much of this teaching was general 'nonspecific' teaching that included all categories of animals. Client grief was taught more generically, whereas, grief of veterinarians was taught using specific examples given by clinicians. CONCLUSION: A more robust end-of-life (EoL) management curriculum that includes all aspects of grief management is likely to increase job satisfaction, client happiness and professional satisfaction.


Subject(s)
Education, Veterinary , Veterinarians , Animals , Curriculum , Grief , Horses , Humans , Schools, Veterinary , Students
6.
Aust Vet J ; 97(11): 433-439, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31418853

ABSTRACT

OBJECTIVE: The aim of this study was to gain a better understanding of Australian pet owners' use of the internet for pet health; how trustworthy they rate various pet health information sources and the use of online information in subsequent veterinary consultations. METHOD: An anonymous questionnaire was developed, consisting of 30 questions, and distributed between March 2018 and May 2018 using convenience sampling through social media venues including Facebook and Twitter. All respondents were over the age of 18, lived in Australia and owned a pet animal. RESULTS: A total of 228 responses were received. The most common sources of pet health information were veterinarians (88.2%) and internet websites (81.1%). Most respondents reported using the internet 'many times per day' at either home or work. The majority of respondents used the internet to seek pet health information either 'not weekly but at least once a month' or 'less than once a month'. Nearly half of the respondents stated that they only 'sometimes' discuss their online findings with their veterinarian. Approximately one half of respondents agreed with the statement that online pet health information had affected their decision about whether to take their pet to the veterinarian. CONCLUSION: This study assesses how pet owners use the internet for pet health information and the role veterinarians can play in helping to facilitate these searches with tools such as information prescriptions. Further large-scale research is needed to help further understand this increasingly important aspect of pet health.


Subject(s)
Information Seeking Behavior , Internet/statistics & numerical data , Ownership , Pets , Adolescent , Adult , Aged , Animals , Australia , Female , Health Knowledge, Attitudes, Practice , Humans , Male , Middle Aged , Pilot Projects , Social Media , Surveys and Questionnaires , Veterinarians/statistics & numerical data , Young Adult
9.
Aust Vet J ; 97(1-2): 10-13, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30693495

ABSTRACT

OBJECTIVE: Investigate Australian veterinarians' perceptions of clients' use of the internet to find pet health information. METHODS: An anonymous online survey was distributed using social media, e-newsletters and veterinary magazines. RESULTS: A total of 85 complete responses were obtained from Australian veterinarians. Most (80%) reported believing that > 80% of their clients have access to the internet at home or work, but 68% thought that the majority of their clients do not understand what they read online. Attitudes regarding the impact of online pet health information on the veterinarian-client relationship were mixed (56% reported negative impact and 33% a positive impact), as well as for clients' use of the internet for information on companion animal health (47% reported negative impact and 38% a positive impact). When asked how often they suggest specific websites to their clients ('information prescriptions'), the majority of veterinarians reported that this is done infrequently. CONCLUSION: This pilot study highlighted the perception of Australian veterinarians of their clients' use of the internet to find pet health information. It also highlighted the need for a large-scale, detailed survey of Australian veterinarians and their views in relation to pet owners and their use of online information. This should include evaluation of information prescriptions and their potential benefits for clients and patients.


Subject(s)
Health Education/methods , Information Dissemination/methods , Information Seeking Behavior , Perception , Professional-Patient Relations , Veterinarians/psychology , Adolescent , Adult , Animals , Australia , Female , Health Literacy , Humans , Internet , Male , Middle Aged , Ownership , Pets , Pilot Projects , Surveys and Questionnaires , Young Adult
10.
Nat Commun ; 9(1): 4055, 2018 10 10.
Article in English | MEDLINE | ID: mdl-30305617

ABSTRACT

Epithelial dysfunction and crypt destruction are defining features of inflammatory bowel disease (IBD). However, current IBD therapies targeting epithelial dysfunction are lacking. The nuclear receptor LRH-1 (NR5A2) is expressed in intestinal epithelium and thought to contribute to epithelial renewal. Here we show that LRH-1 maintains intestinal epithelial health and protects against inflammatory damage. Knocking out LRH-1 in murine intestinal organoids reduces Notch signaling, increases crypt cell death, distorts the cellular composition of the epithelium, and weakens the epithelial barrier. Human LRH-1 (hLRH-1) rescues epithelial integrity and when overexpressed, mitigates inflammatory damage in murine and human intestinal organoids, including those derived from IBD patients. Finally, hLRH-1 greatly reduces disease severity in T-cell-mediated murine colitis. Together with the failure of a ligand-incompetent hLRH-1 mutant to protect against TNFα-damage, these findings provide compelling evidence that hLRH-1 mediates epithelial homeostasis and is an attractive target for intestinal disease.


Subject(s)
Epithelium/pathology , Homeostasis , Inflammatory Bowel Diseases/metabolism , Inflammatory Bowel Diseases/pathology , Receptors, Cytoplasmic and Nuclear/metabolism , Animals , Cell Differentiation , Cell Survival , Colitis/metabolism , Colitis/pathology , Disease Models, Animal , Humans , Mice , Organoids/metabolism , Receptors, Notch/metabolism , Tumor Necrosis Factor-alpha/metabolism
11.
J Orthop Res ; 2018 Feb 22.
Article in English | MEDLINE | ID: mdl-29469223

ABSTRACT

No disease-modifying osteoarthritis (OA) drugs are available to prevent posttraumatic osteoarthritis (PTOA). Mitochondria (MT) mediate the pathogenesis of many degenerative diseases, and recent evidence indicates that MT dysfunction is a peracute (within minutes to hours) response of cartilage to mechanical injury. The goal of this study was to investigate cardiolipin-targeted mitoprotection as a new strategy to prevent chondrocyte death and cartilage degeneration after injury. Cartilage was harvested from bovine knee joints and subjected to a single, rapid impact injury (24.0 ±1.4 MPa, 53.8 ± 5.3 GPa/s). Explants were then treated with a mitoprotective peptide, SS-31 (1µM), immediately post-impact, or at 1, 6, or 12 h after injury, and then cultured for up to 7 days. Chondrocyte viability and apoptosis were quantified in situ using confocal microscopy. Cell membrane damage (lactate dehydrogenase activity) and cartilage matrix degradation (glycosaminoglycan loss) were quantified in cartilage-conditioned media. SS-31 treatment at all time points after impact resulted in chondrocyte viability similar to that of un-injured controls. This effect was sustained for up to a week in culture. Further, SS-31 prevented impact-induced chondrocyte apoptosis, cell membrane damage, and cartilage matrix degeneration. CLINICAL SIGNIFICANCE: This study is the first investigation of cardiolipin-targeted mitoprotective therapy in cartilage. These results suggest that even when treatment is delayed by up to 12 h after injury, mitoprotection may be a useful strategy in the prevention of PTOA. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-10, 2018.

12.
J Sci Educ Technol ; 27(6): 566-580, 2018 Dec.
Article in English | MEDLINE | ID: mdl-31105416

ABSTRACT

Mobile applications (apps) for learning technical scientific content are becoming increasingly popular in educational settings. Neuroscience is often considered complex and challenging for most students to understand conceptually. iNeuron is a recently developed iOS app that teaches basic neuroscience in the context of a series of scaffolded challenges to create neural circuits and increase understanding of nervous system structure and function. In this study, four different ways to implement the app within a classroom setting were explored. The goal of the study was to determine the app's effectiveness under conditions closely approximating real-world use, and to evaluate whether collaborative play and student-driven navigational features contributed to its effectiveness. Students used the app either individually or in small groups, and used a version with either a fixed or variable learning sequence. Student performance on a pre- and post- neuroscience content assessment was analyzed and compared between students who used the app and a control group receiving standard instruction, and logged app data were analyzed. Significantly greater learning gains were found for all students who used the app compared to control. All four implementation modes were effective in producing student learning gains relative to controls, but did not differ in their effectiveness to one another. In addition, students demonstrated transfer of information learned in one context to another within the app. These results suggest that teacher-led neuroscience instruction can be effectively supported by a scaffolded, technology-based curriculum which can be implemented in multiple ways to enhance student learning.

13.
Aust Vet J ; 95(6): 189-193, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28555952

ABSTRACT

OBJECTIVE: To determine what veterinary students in Australia and New Zealand consider important competences in companion animal welfare and ethics (AWE) required on their first day of practice, and to explore how their priorities relate to gender and stage of study. METHODS: Undergraduate students at all veterinary schools in Australia and New Zealand were sent an online survey. A subset of questions required participants to rank the importance of preselected AWE topics pertaining to companion animals. Data were analysed to determine differences in the way students of different gender or academic stage prioritised each of these AWE topics. RESULTS: Of 3220 currently enrolled students, 851 participated in the survey: 79% were female, 17% male, 4% unspecified. Ranking of the AWE topics, from highest to lowest importance, was: neutering, companion animal husbandry, euthanasia, behaviour and training, animal breeding, over-servicing in relation to animal needs and cosmetic surgery. Female students consistently ranked competency in AWE issues surrounding neutering more highly than male students (P = 0.006). Students in senior years of study ranked the importance of competency in animal abuse/hoarding (P = 0.048), shelter medicine (P = 0.012) and animal breeding (P = 0.002) less highly than those in junior years. CONCLUSIONS: Australasian veterinary students placed more importance on competency in AWE issues associated with clinical practice (such as neutering and euthanasia) than on professional behaviours (such as over-servicing and animal breeding). However, we consider that emphasis should still be placed on developing graduate competency in the latter categories to reflect growing societal concerns about companion animal over-supply and inappropriate professional conduct.


Subject(s)
Animal Husbandry , Animal Welfare , Attitude , Students/psychology , Animal Husbandry/ethics , Animal Welfare/ethics , Animals , Australia , Clinical Competence , Euthanasia, Animal , Female , Humans , Internet , Male , New Zealand , Pets , Schools, Veterinary , Sex Distribution , Sterilization, Reproductive/psychology , Sterilization, Reproductive/veterinary , Surveys and Questionnaires
14.
Animal ; 9(8): 1379-85, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25874817

ABSTRACT

An understanding of the perceived importance of a variety of factors affecting the ease of handling of sheep and the interactions between these factors is valuable in improving profitability and welfare of the livestock. Many factors may contribute to animal behaviour during handling, and traditionally these factors have been assessed in isolation under experimental conditions. A human social component to this phenomenon also exists. The aim of this study was to gain a deeper understanding of the importance of a variety of factors affecting ease of handling, and the interactions between these from the perspective of the livestock transporter. Qualitative interviews were used to investigate the factors affecting sheep behaviour during handling. Interview transcripts underwent thematic analysis. Livestock transporters discussed the effects of attitudes and behaviours towards sheep, helpers, facilities, distractions, environment, dogs and a variety of sheep factors including breed, preparation, experience and sex on sheep behaviour during handling. Transporters demonstrated care and empathy and stated that patience and experience were key factors determining how a person might deal with difficult sheep. Livestock transporters strongly believed facilities (ramps and yards) had the greatest impact, followed by sheep experience (naivety of the sheep to handling and transport) and breed. Transporters also discussed the effects of distractions, time of day, weather, dogs, other people, sheep preparation, body condition and sheep sex on ease of handling. The concept of individual sheep temperament was indirectly expressed.


Subject(s)
Animal Husbandry/methods , Animal Welfare/standards , Behavior, Animal/physiology , Sheep, Domestic/physiology , Transportation/methods , Animals , Dogs , Environment , Humans , Interviews as Topic , Sheep
15.
Can J Vet Res ; 72(3): 259-68, 2008 Apr.
Article in English | MEDLINE | ID: mdl-18505190

ABSTRACT

In the late fall of 2004 more severe lesions of porcine circovirus-2 associated disease (PCVAD) than usual occurred during an outbreak of porcine circovirus-2 (PCV-2) infection in Ontario nursery and grower/finisher pigs. The lesions were of unprecedented severity and included diffuse bronchointerstitial pneumonia, granulomatous enteritis, vasculitis, interstitial nephritis, and new lesions of splenic infarction. Some affected herds had up to 50% mortality. The outbreak correlated with the sudden emergence of a variant PCV-2, with PCR restriction fragment length polymorphism (RFLP) type 321. Phylogenetic comparison of ORF2 sequences and full genome sequences showed the new variant to be different from the previously dominant RFLP type 422 viruses, and similar to viruses that had occurred in France and other European and Asian countries. A subsequent retrospective study showed a statistically significant increase in the frequency of histological lesions in lymph node, spleen, lung, small intestine, colon and kidney, for pigs spontaneously infected with RFLP type 321, compared with the older RFLP type 422 strain. Viral burden, based on IHC staining in lymph node, also showed a statistically significant increase in pigs infected with the newer variant RFLP type 321, compared with the older RFLP type 422 strain. This enhanced virulence in pigs infected with PCV-2 RFLP type 321 strain may be related to the genetic differences in this new strain of PCV-2. This virus is now the dominant strain of PCV-2 virus found in Ontario and Quebec swine.


Subject(s)
Circoviridae Infections/veterinary , Circovirus/pathogenicity , Disease Outbreaks/veterinary , Polymorphism, Restriction Fragment Length , Swine Diseases/pathology , Animals , Circoviridae Infections/epidemiology , Circoviridae Infections/pathology , Circoviridae Infections/virology , Circovirus/genetics , Female , Genetic Variation , Immunohistochemistry/veterinary , Male , Molecular Sequence Data , Ontario/epidemiology , Phylogeny , Quebec/epidemiology , Sequence Analysis, DNA , Severity of Illness Index , Swine , Swine Diseases/epidemiology , Swine Diseases/virology , Viral Load/veterinary , Virulence/genetics
16.
Acta Crystallogr C ; 61(Pt 6): m253-5, 2005 Jun.
Article in English | MEDLINE | ID: mdl-15930656

ABSTRACT

The title compound, DL-threonine-arsenic acid (1/1), C4H9NO3.H3AsO4, is an unusual adduct containing zwitterionic threonine and neutral arsenic acid molecules. The component species interact by way of N-H...O and O-H...O hydrogen bonds, leading to parallel [001] chains of threonine and arsenic acid molecules which are crosslinked by further O-H...O and N-H...O bonds, resulting in a three-dimensional network.

17.
Appl Environ Microbiol ; 70(11): 6501-11, 2004 Nov.
Article in English | MEDLINE | ID: mdl-15528512

ABSTRACT

Humans are exposed to Campylobacter spp. in a range of sources via both food and environmental pathways. For this study, we explored the frequency and distribution of thermophilic Campylobacter spp. in a 10- by 10-km square rural area of Cheshire, United Kingdom. The area contains approximately 70, mainly dairy, farms and is used extensively for outdoor recreational activities. Campylobacter spp. were isolated from a range of environmental samples by use of a systematic sampling grid. Livestock (mainly cattle) and wildlife feces and environmental water and soil samples were cultured, and isolates were presumptively identified by standard techniques. These isolates were further characterized by PCR. Campylobacter jejuni was the most prevalent species in all animal samples, ranging from 11% in samples from nonavian wildlife to 36% in cattle feces, and was isolated from 15% of water samples. Campylobacter coli was commonly found in water (17%) and sheep (21%) samples, but rarely in other samples. Campylobacter lari was recovered from all sample types, with the exception of sheep feces, and was found in moderate numbers in birds (7%) and water (5%). Campylobacter hyointestinalis was only recovered from cattle (7%) and birds (1%). The spatial distribution and determinants of C. jejuni in cattle feces were examined by the use of model-based spatial statistics. The distribution was consistent with very localized within-farm or within-field transmission and showed little evidence of any larger-scale spatial dependence. We concluded that there is a potentially high risk of human exposure to Campylobacter spp., particularly C. jejuni, in the environment of our study area. The prevalence and likely risk posed by C. jejuni-positive cattle feces in the environment diminished as the fecal material aged. After we took into account the age of the fecal material, the absence or presence of rain, and the presence of bird feces, there was evidence of significant variation in the prevalence of C. jejuni-positive cattle feces between grazing fields but no evidence of spatial clustering beyond this resolution. The spatial pattern of C. jejuni is therefore consistent with that for an organism that is ubiquitous in areas contaminated with cattle feces, with a short-scale variation in infection intensity that cannot be explained solely by variations in the age of the fecal material. The observed pattern is not consistent with large-scale transmission attributable to watercourses, wildlife territories, or other geographical features that transcend field and farm boundaries.


Subject(s)
Campylobacter/classification , Campylobacter/isolation & purification , Environmental Microbiology , Animals , Animals, Domestic/microbiology , Animals, Wild/microbiology , Campylobacter/genetics , Campylobacter Infections/microbiology , Campylobacter Infections/veterinary , Cattle , Cattle Diseases/microbiology , Environmental Monitoring , Feces/microbiology , Models, Biological , Polymerase Chain Reaction , Species Specificity
18.
Planta ; 219(3): 468-78, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15054660

ABSTRACT

The control of rhythmic emission of floral volatiles emitted from Rosa damascena semperflorens cv. 'Quatre Saisons' throughout floral development under various light regimes was studied. 2-Phenylethanol was the major volatile emitted in addition to monoterpenols, oxidised monoterpenols, monoterpenes and aromatic compounds. All detected volatiles were emitted rhythmically, with maximum peaks coinciding 8-10 h into a 12-h photoperiod. For some compounds a secondary, nocturnal peak was apparent. The primary and secondary maxima both occurred at approximately 24-h intervals. Rhythms appeared to be regulated endogenously: rhythmic emission continued upon exposure to continuous light or continuous darkness, and a phase shift in emission was induced upon inversion of the photoperiod. Additionally, emission continued after flower excision. A similar profile of free volatiles was stored within the floral tissue, together with glycosidic forms of 2-phenylethanol (>99% beta-D-glucoside), benzyl alcohol, citronellol and geraniol. Regression analysis indicated a significant decrease in glycosylated 2-phenylethanol through the photoperiod. These results suggest that glycosylated volatiles stored within petals may be a source of rhythmically emitted volatiles.


Subject(s)
Rosa/metabolism , Alcohols/metabolism , Flowers/metabolism , Glycosylation , Oils, Volatile/metabolism , Periodicity , Phenylethyl Alcohol/metabolism , Photoperiod
19.
Epidemiol Infect ; 129(1): 147-53, 2002 Aug.
Article in English | MEDLINE | ID: mdl-12211582

ABSTRACT

Transmission is the driving force in the dynamics of any infectious disease. A crucial element in understanding disease dynamics, therefore, is the 'transmission term' describing the rate at which susceptible hosts are 'converted' into infected hosts by their contact with infectious material. Recently, the conventional form of this term has been increasingly questioned, and new terminologies and conventions have been proposed. Here, therefore, we review the derivation of transmission terms, explain the basis of confusion, and provide clarification. The root of the problem has been a failure to include explicit consideration of the area occupied by a host population, alongside both the number of infectious hosts and their density within the population. We argue that the terms 'density-dependent transmission' and 'frequency-dependent transmission' remain valid and useful (though a 'fuller' transmission term for the former is identified), but that the terms 'mass action', 'true mass action' and 'pseudo mass action' are all unhelpful and should be dropped. Also, contrary to what has often been assumed, the distinction between homogeneous and heterogeneous mixing in a host population is orthogonal to the distinction between density- and frequency-dependent transmission modes.


Subject(s)
Disease Transmission, Infectious , Humans , Models, Biological
20.
Phytochemistry ; 60(6): 611-7, 2002 Jul.
Article in English | MEDLINE | ID: mdl-12126708

ABSTRACT

Flowering Mahonia japonica plants were subjected to controlled environments and the floral volatiles emitted from whole racemes (laterals) were trapped by Porapak Q adsorbent and analysed by GC-FID. An experiment with photoperiods of 6 and 9 h at constant temperature (10+/-1 degrees C) demonstrated that photoperiod was the stimulus for enhanced emission of most volatiles. Small quantitative differences in emitted fragrance composition were observed between light and dark periods and between plants acclimatised to different photoperiods. Maximum rates of emission occurred in the middle of the light period; aromatic compounds (benzaldehyde, benzyl alcohol and indole) displayed a more rapid increase and subsequent decline compared with monoterpenes (cis- and trans-ocimene and linalool). When the photoperiod was extended from 6 to 9 h, maximum rates of emission continued throughout the additional 3 h. Total emission (microg/h) of volatiles was 2-fold greater in the day-time (DT) (39.7 microg/h) compared with the night-time (NT) (19.8 microgg/h) under a 6 h photoperiod and was not significantly different from total emission under a 9 h photoperiod.


Subject(s)
Benzaldehydes/analysis , Benzyl Alcohol/analysis , Berberidaceae/chemistry , Indoles/analysis , Berberidaceae/physiology , Circadian Rhythm/physiology , Gas Chromatography-Mass Spectrometry , Photoperiod , Temperature , Time Factors , Volatilization
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