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81.
Wildfire effects on understory shrubs and herbs, regeneration of the seedling and sapling size classes, and downed and dead fuels were assessed in a mixed conifer stand located in the Lake Tahoe Basin in which California white fir (Abies concolor var. lowiana [Gord.] Lemm.) was most abundant but with Jeffrey pine (Pinus jeffreyi Grev. & Balf.) also prevalent. In burned and unburned stand portions, prefire measurements served as a basis of comparison for the postfire measurements pertinent to each study component. Fire severely suppressed the understory vegetation, which was dominated by shrubs such as bush chinquapin (Chrysolepis sempervirens [Kellogg] Hjelmqvist) and antelope bitterbrush (Purshia tridentata [Pursh] DC.), while a tepid postfire recovery of most of the preexisting species in the burned stand portion was augmented by new ones, including shrubs such as snowbrush (Ceanothus velutinus Douglas ex Hook.) and whitethorn (Ceanothus cordulatus Kellogg) ceanothus and herbs such as Holboell's rockcress (Arabis holboellii Hornem.). Tree seedling abundance was also substantially reduced in the burned portion, but the postfire population was dominated by Jeffrey pine whereas white fir had been most prevalent originally. Sapling regeneration was eliminated from the burned stand portion regardless of species. Downed and dead fuel loading was severely diminished by the fire, especially regarding fine fuels, permitting subsequent sheet erosion to imperil new seedling regeneration. These results contribute to an understanding of the direction and pace of postwildfire succession on sites occupied by Sierra Nevada mixed conifer and similar forest cover types, which is critical in decisions concerning the need for, and extent of, postfire site rehabilitation measures.  相似文献   
82.
83.
Abstract

The longleaf pine (Pinus palustris Mill.) forests are important ecosystems in the southeastern USA because of their ecological and economic value. Since European settlement, longleaf pine ecosystems have dramatically declined in extent, to the degree that they are now listed as endangered ecosystems. Its sporadic seed production, which limits the frequency of natural regeneration, is identified as a significant factor in this decline. Previous studies did not characterize the complexity in cone production. Here a method of multiscale entropy is used to analyze long-term data for cone production in longleaf pine forests at six sites across its native range. Our results indicate that there exists a regime shift for cone production at each site. The corresponding time scales of the regime shift are generally 1–9, 10–12, 13–16, and 17–24 yr. Overall patterns for the complexity of cone production with the change of time scale are similar among sites, with exception of the Red Hills (FL). There are high correlations between entropy of cone production and entropy of annual mean air temperature and annual total precipitation at all sites. These results provide new insight into the complexity of cone production of longleaf pine forests with significant management implications.  相似文献   
84.
Background: Objectives were to examine the effects of selenium (Se) supply and maternal nutritional plane during gestation on mammary gland growth, cellular proliferation, and vascularity at parturition and d 20 of lactation. Rambouillet primiparous ewes (n = 84) were allocated to treatments in a 2 x 3 factorial. Factors were dietary Se (adequate Se [ASe, 11.5 μg/kg BW] or high Se [HSe, 77.0 μg/kg BVV]) and nutritional plane (60% IRES], 100% [CON], or 140% [EXC]). At parturition, lambs were removed and 42 ewes (7/treatment) were necropsied. Remaining ewes were fed a common diet meeting requirements for lactation and mechanically milked twice daily until necropsy on d 20. At both necropsy periods, mammary glands were dissected and tissues harvested. Samples were analyzed for RNA, DNA, and protein content, cell proliferation, and vascularity. Where interactions were present (P 〈 0.05), least squares means from the highest-order interaction are presented. Results: Final body weight of ewes was least (P 〈 0.002) in RES, intermediate for CON, and greatest for EXC, regardless of stage of the ewe at necropsy (parturition or d 20 of lactation). In ewes necropsied at parturition, mammary glands were heavier (P = 0.02) in EXC compared to RES, with CON intermediate. Concentration of RNA (rag/g) was decreased (P= 0.01) in EXC compared to CON at parturition. There was a tendency (P= 0.07) for a Se by nutrition interaction in percentage of cells proliferating where ASe-EXC ewes had greater (P_〈 0.02) number of proliferating cells then all other treatments. Mammary vascular area tended (P = 0.08) to be affected by a Se by nutrition interaction where ASe-CON had less (P= 0.007) vascular area than HSe-CON ewes. In ewes necropsied at d 20 of lactation, the number of alveoli per area was decreased (P 〈- 0.05) in RES compared to CON and EXC-fed ewes. Conclusions: Results of this study indicate that proper maternal nutritional plane during gestation is important for mammary gland development, even out to d 20 of lactation.  相似文献   
85.
RATIONALE FOR THE STUDY: The aims of the study, conducted as a student research project in the 2004-5 session, were to develop an interactive, online computer-aided learning (CAL) package on the topic of small-animal husbandry; to validate the resource as a suitable lecture replacement for first-year veterinary students; and to raise awareness of current guidelines and legislation relating to small-animal housing among local catteries and kennels and in the wider community. METHODOLOGY: Quantitative feedback was collected from student and teaching staff using paper-based questionnaires. Qualitative feedback was gathered from open questionnaire responses and through focus-group discussions with students. Student examination marks were compared for 2004 and 2005, allowing a comparison of student performance before and after the replacement of the traditional lecture with the CAL package. Ethical approval for the study was granted by the faculty's Ethics Committee. RESULTS AND CONCLUSIONS: The CAL package on small-animal housing was well received by teaching staff and students; student performance in examinations improved after the introduction of the CAL program, suggesting that it provides a suitable alternative to didactic teaching. The creation and distribution of the CAL package on CD-ROM and its availability via the Internet are intended to contribute to small-animal welfare education in local catteries and kennels and further afield. The package sets a precedent for the development of more Internet-based, student-authored CAL packages in the future, providing additional resources for independent learning.  相似文献   
86.
AIMS: To establish the incidence, frequency and type of deliberate animal abuse seen in veterinary practice in New Zealand, and ascertain veterinarians' knowledge of human abuse within the families where animal abuse was occurring. To explore attitudes of veterinarians to and knowledge about the correlation between animal abuse and human violence, and their perceived role in dealing with such issues. METHODS: A postal questionnaire was sent to practising veterinarians in New Zealand. It covered demographics, frequency and type of animal abuse cases seen, awareness of violence towards humans, within families where animal abuse was seen, the methods used for managing animal and human abuse, the incidence of psychological abuse of animals, and the attitudes of veterinarians towards and their beliefs about the link between animal abuse and human violence. RESULTS: A total of 383/1,412 (27% response rate) questionnaires with useable data were returned. Within the group of respondents, the sexes were evenly represented; 40% of respondents worked in small-animal practice, 50% in mixed practice and 10% in large-animal practice. Deliberate animal abuse had been seen by 63% of respondents in the last 5 years; 37% of these had seen such cases once a year or less, while 9% had seen abuse cases at least four times a year. Dogs were the species most commonly reported as abused, followed, in numerical order, by cats, cattle and horses. Among respondents who had seen deliberate animal abuse, 16% either knew of (4%) or suspected (12%) human abuse within the families of the abused animals. A clear majority of responding veterinarians agreed with the statement that people who abuse their animals are more likely to abuse their children (77%) or spouse (70%). CONCLUSIONS: The survey indicated that the majority of respondents had seen cases of animal abuse within the previous 5 years, and dogs were the species most often reported abused. Responding veterinarians felt a strong ethical duty to deal with cases of animal abuse, but they were less comfortable about issues of human abuse, even though the awareness of the link between abuse of animals and abuse of humans was relatively high. CLINICAL RELEVANCE: The greater the awareness of animal abuse and its linkage with human abuse, the greater the possibility that veterinarians can contribute in a meaningful way to the reduction of violence in society.  相似文献   
87.
Zoonotic viruses, such as H5N1 Avian Influenza, pose major threats to both animals and humans, and with this in mind there is a need for the development of new anti-viral strategies. The cytokine interleukin-12 (IL-12) is known to play a pivotal regulatory role in the anti-viral response due to its role in the induction of the key anti-viral cytokine IFN-gamma. Therefore, strategies which provide a means for the production of therapeutic quantities of IL-12 may be of major benefit. Here we describe the development of biologically active Escherichia coli (E. coli) derived chicken IL-12 (ChIL-12). The single chain ChIL-12 gene was cloned into the pET32b expression vector, transformed into the BL-21 E. coli strain and expression induced with IPTG. Over expressed protein was solubilised with zwittergent detergent and isolated utilising Nickel ion affinity chromatography. Biological activity was determined as ChIL-12 stimulated proliferation of pre-treated T-cells in vitro. This study is the first example of a biologically active E. coli derived IL-12 from a non-mammalian vertebrate subsequently providing a means for testing the anti-viral therapeutic potential of ChIL-12 in an in vivo model.  相似文献   
88.
Aims: To assess the prevalence of obesity in adult dogs and cats presented to first-opinion veterinary clinics in the North Island of New Zealand for routine vaccination appointments, using electronic medical records.

Methods: Ten first-opinion veterinary clinics across the North Island of New Zealand provided electronic medical records for all routine vaccination appointments for adult (>1 year old) dogs and cats between 1 January 2011 and 30 June 2016. Animals with a body condition score (BCS) of 6 or 7 on a 9-point scale and 4 on a 5-point scale were classified as overweight; those with a BCS of 8 or 9 on a 9-point scale and 5 on a 5-point scale were classified as obese. A total of 106,144 records were available over the study period, of which 48,041 (45.2%) had both a recorded weight and BCS.

Results: Of the 24,247 records for dogs with both BCS and weight, 6,324 (26.1%) were classified as overweight, and 551 (2.3%) as obese. The prevalence of dogs classified as overweight or obese was highest in dogs aged between 5–13 years. The odds of desexed dogs being classified as overweight or obese was greater than the odds for intact dogs (OR=1.42 (95% CI=1.29–1.57), p<0.001) adjusting for the effects of age. Of the 23,794 records for cats with a recorded weight and BCS, 5,222 (21.9%) were classified as overweight, and 622 (2.6%) as obese. The prevalence of cats classified as overweight or obese was highest in cats aged between 5–11 years. The odds of desexed cats being classified as overweight or obese tended to be greater than the odds for intact cats (OR=1.14 (95% CI=0.98–1.31); p=0.075), adjusting for the effects of age.

Conclusions: Although there are limitations with using electronic medical records to estimate the prevalence of obesity in companion animal populations, the results highlight that a significant number of animals presenting for routine vaccination appointments were classified as overweight or obese.

Clinical Relevance: It is important for veterinarians to record both patient body condition and weight during routine preventative care appointments to allow accurate ongoing monitoring of trends in obesity at both the patient and population levels.

Abbreviations: BCS: Body condition score  相似文献   

89.
Although considerable conservation resources have been committed to develop and use law enforcement monitoring and management tools such as SMART, measures of success are ill‐defined and, to date, few reports detail results post‐implementation. Here, we present 4 case studies from protected areas with Amur tigers (Panthera tigris altaica) in Russia, in which indicators of success were defined and evaluated at each. The ultimate goal was an increase in tiger numbers to 1 individual/100 km2 at each site. We predicted that improvements in law enforcement effectiveness would be followed by increases in prey numbers and, subsequently, tiger numbers. We used short‐term and long‐term indicators of success, including: (i) patrol team effort and effectiveness; (ii) catch per unit effort indicators (to measure reductions in threats); and (iii) changes in target species numbers. In addition to implementing a monitoring system, we focused on improving law enforcement management using an adaptive management process. Over 4 years, we noted clear increases in patrol effort and a partial reduction in threats. Although we did not detect clear trends in ungulate numbers, tiger populations remained stable or increased, suggesting that poaching of tigers may be more limiting than prey depletion. Increased effectiveness is needed before a clear reduction in threats can be noted, and more time is needed before detecting responses in target populations. Nonetheless, delineation of concrete goals and indicators of success provide a means of evaluating progress and weaknesses. Such monitoring should be a central component of law enforcement strategies for protected areas.  相似文献   
90.

Background

Low cost unmanned aerial systems (UAS) have great potential for rapid proximal measurements of plants in agriculture. In the context of plant breeding and genetics, current approaches for phenotyping a large number of breeding lines under field conditions require substantial investments in time, cost, and labor. For field-based high-throughput phenotyping (HTP), UAS platforms can provide high-resolution measurements for small plot research, while enabling the rapid assessment of tens-of-thousands of field plots. The objective of this study was to complete a baseline assessment of the utility of UAS in assessment field trials as commonly implemented in wheat breeding programs. We developed a semi-automated image-processing pipeline to extract plot level data from UAS imagery. The image dataset was processed using a photogrammetric pipeline based on image orientation and radiometric calibration to produce orthomosaic images. We also examined the relationships between vegetation indices (VIs) extracted from high spatial resolution multispectral imagery collected with two different UAS systems (eBee Ag carrying MultiSpec 4C camera, and IRIS+ quadcopter carrying modified NIR Canon S100) and ground truth spectral data from hand-held spectroradiometer.

Results

We found good correlation between the VIs obtained from UAS platforms and ground-truth measurements and observed high broad-sense heritability for VIs. We determined radiometric calibration methods developed for satellite imagery significantly improved the precision of VIs from the UAS. We observed VIs extracted from calibrated images of Canon S100 had a significantly higher correlation to the spectroradiometer (r = 0.76) than VIs from the MultiSpec 4C camera (r = 0.64). Their correlation to spectroradiometer readings was as high as or higher than repeated measurements with the spectroradiometer per se.

Conclusion

The approaches described here for UAS imaging and extraction of proximal sensing data enable collection of HTP measurements on the scale and with the precision needed for powerful selection tools in plant breeding. Low-cost UAS platforms have great potential for use as a selection tool in plant breeding programs. In the scope of tools development, the pipeline developed in this study can be effectively employed for other UAS and also other crops planted in breeding nurseries.
  相似文献   
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