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1.
翻耕对半干旱区高寒草甸地表水热条件的影响   总被引：1，自引：1，他引：0  
通过对青藏高原东北缘半干旱盆地退化高寒草甸地表观测资料的分析,研究了土壤含水量、地表温度和植被盖度之间的相互关系,分析了翻耕所导致的地表植被破坏和土壤属性的变化对高寒草甸的影响。结果表明:1）较高植被覆盖区域内土壤含水量较高;2）降水后,较低植被覆盖区域内地表温度较低,地表蒸散量较大;3）在长时期缺乏降水的情况下,较低植被盖度区域内地表温度较高,土壤含水量偏低。以上结果说明,翻耕后导致的地表植被破坏和土壤属性变化,会导致翻耕区内地表蒸散偏大,更容易出现土壤水分不足的现象,不适合半干旱区高寒草甸群落的恢复。因此,采取增加灌溉或者免耕补播等不破坏地表植被的补播方式,可能更适合该地区内的植被恢复。  相似文献   

2.
It was the aim of this study to investigate the regional variations in surface temperature and sweating rate and to visualize body thermal windows responsible for the dissipation of excess body heat in dromedary camels. This study was conducted on five dromedary camels with mean body weight of 450 ± 20.5 kg and 2 years of age. Sweating rate, skin and body surface temperature showed significant (P < 0.001) circadian variation together with the variation in ambient temperature. However, daily mean values of sweating rate, skin and body surface temperature measured on seven regions of the camel body did not significantly differ. The variation in body surface temperature compared to the variation in skin temperature was higher in the hump compared to the axillary and flank regions, indicating the significance of camel's fur in protecting the skin from daily variation in ambient temperature. Infrared thermography revealed that flank and axillary regions had lower thermal gradients at higher ambient temperature (Ta) and higher thermal gradients at lower Ta, which might indicate the working of flank and axillary regions as thermal windows dissipating heat during the night. Sweating rate showed moderate correlation to skin and body surface temperatures, which might indicate their working as potential thermal drivers of sweating in camels.  相似文献   

3.
Estimates of heat stress relief needs for Holstein dairy cows   总被引：3，自引：0，他引：3  
Estimates of environmental heat stress are required for heat stress relief measures in cattle. Heat stress is commonly assessed by the temperature-humidity index (THI), the sum of dry and wet bulb temperatures. The THI does not include an interaction between temperature and humidity, although evaporative heat loss increases with rising air temperature. Coat, air velocity, and radiation effects also are not accounted for in the THI. The Holstein dairy cow is the primary target of heat stress relief, followed by feedlot cattle. Heat stress may be estimated for a variety of conditions by thermal balance models. The models consist of animal-specific data (BW, metabolic heat production, tissue and coat insulation, skin water loss, coat depth, and minimal and maximal tidal volumes) and of general heat exchange equations. A thermal balance simulation model was modified to adapt it for Holstein cows by using Holstein data for the animal characteristics in the model, and was validated by comparing its outputs to experimental data. Model outputs include radiant, convective, skin evaporative, respiratory heat loss and rate of change of body temperature. Effects of milk production (35 and 45 kg/d), hair coat depth (3 and 6 mm), air temperature (20 to 45 degrees C), air velocity (0.2 to 2.0 m/s), air humidity (0.8 to 3.9 kPa), and exposed body surface (100, 75, and 50%) on thermal balance outputs were examined. Environmental conditions at which respiratory heat loss attained approximately 50% of its maximal value were defined as thresholds for intermediate heat stress. Air velocity increased and humidity significantly decreased threshold temperatures, particularly at higher coat depth. The effect of air velocity was amplified at high humidity. Increasing milk production from 35 to 45 kg/d decreased threshold temperature by 5 degrees C. In the lying cow, the lower air velocity in the proximity of body surface and the smaller exposed surface markedly decrease threshold temperature. The large variation in thresholds due to environmental and animal factors justifies the use of thermal balance-based indices for estimating heat stress. Such an approach may make possible estimates of threshold temperatures at which heat stress relief is required for widely different cattle types and environmental situations.  相似文献   

4.
The purpose of the study was the evaluation of the thermal changes within mammary gland in cows, after experimentally invoked inflammation, developed as a result of 60 ml of 20% NaCl solution given directly into the udder (A and D quarters). Three hours after injection, the increased' temperature of teats and their bases by 2.26 degrees C and 0.58 degree C, respectively, was stated. The temperature was still increased after 6 hours from NaCl solution injection. It was accompanied by increase of heat flux from the skin surface by 50.17 mW/cm2 taken from the teat surface, and by increased values of Burton Index--the tissue blood supply index.  相似文献   

5.
Realistic assessments of the impacts of global warming on population extinction risk are likely to require an integrated analysis of the roles of standing genetic variation, microhabitat thermal complexity, and the inter‐individual variation of heat tolerance due to both genetic differences and seasonal acclimatization effects. Here, we examine whether balancing selection and microhabitat temperature heterogeneity can interact to enhance the population persistence to thermal stress for the black mussel Septifer virgatus. We deployed biomimetic data loggers on the shore to measure the microhabitat‐specific thermal variation from June 2014 to April 2016. Thermal tolerance of specimens was indexed by measuring effects of temperature on heart rate. Genotyping of specimens was performed using double digestion restriction association RADSeq (ddRADseq). Our results show that inter‐individual variations in thermal tolerance correlate significantly with genetic differences at some specific gene loci, and that heterozygotes have higher thermal tolerances than homozygotes. The observed seasonal changes in genotype frequency suggest that these loci are under balancing selection. The ability of thermally resistant heterozygotes to survive in sun‐exposed microhabitats acts to balance the loss of homozygotes during summer and enable the persistence of genetic polymorphisms. Population persistence of the mussel is also facilitated by the micro‐scale variation in temperature, which provides refugia from thermal stress. Our results emphasize that inter‐individual variation in thermal tolerance and in microhabitat heterogeneity in temperature are important for the persistence of populations in rocky shore habitats.  相似文献   

6.
Skin lacerations on the hind legs of horses often cause large defects on the cranial surface of the hock and cannon regions. The treatment of these present significant logistic problems due to the amount of movement of the area and the difficulties of bandaging and immobilisation, as well as a tendency to form exuberant granulation tissue (or ‘proud flesh’) Acupuncture beads were used as a means of suppressing granulation and maximising epithelial ingrowth, using the principle that ‘acupuncture has been shown to help bring the body back towards normality’. The aim in these cases was healing of the skin lesions with the least effort and cost possible. The technique eliminated the need for resection of any granulation tissue after the beads were implanted, the amount of bandaging was drastically reduced and eliminated in a lot of cases, and the results were cosmetically very acceptable and functional. Digital photography and measurements of the changes in the size of the lesions were used to document the results. This study shows that the formation of exuberant granulation tissue or ‘proud flesh’ in equine skin wounds on the cranial surface of the hock and cannon bone can be controlled by a single acupuncture bead treatment. Long‐term follow‐up of the cases over 18+ months confirms the ongoing effects of the acupuncture beads, resulting in the completion of wound healing and reduction of fibrosis.  相似文献   

7.
Thermography is a non-contact, non-invasive technique that detects surface heat emitted as infrared radiation. Because skin temperature reflects the status of underlying tissue metabolism and blood circulation, abnormal thermal patterns can signify areas of superficial inflammation. The objective of this study was to determine if thermography could detect the injection of analgesic and neurolytic agents and surgical palmar digital neurectomy. Procedures evaluated include injection of the lumbar region, suspensory ligaments, tibial nerve, palmar digital nerves, and palmar digital neurectomy. Thermographic images were obtained before and after the procedures until a significant difference was no longer detected. Local injection of the lumbar region and the suspensory ligament produced detectable thermal patterns for two days, and tibial nerve infiltration with a neurolytic agent was significant for two days. Analgesia of the palmar nerves was significant for 24h with bupivicaine, compared to five days for ammonium chloride. Palmar digital neurectomy produced more variable thermal patterns. While sensitive enough to detect changes in heat patterns from control regions, thermography is not specific enough to discriminate between procedures and injury inducing an inflammatory response.  相似文献   

8.
A 5‐year‐old female spayed Shetland sheepdog presented for evaluation of bandage sores on the left pelvic limb after a splint was placed to stabilise a digit fracture incurred approximately 2 weeks previously. Multiple areas of necrosis were identified upon bandage removal. After debridement of devitalised tissue, a 4 cm wound on the plantar surface of the metatarsal bones (with exposed bone and tendons) remained. The Papineau technique (which involves removal of infected or necrotic tissue, placement of autogenous cancellous bone graft within a wound, and delayed skin closure) was used to treat this wound. Use of bone graft in this manner aims to promote early granulation tissue formation and reduce the time until wound reconstruction can be performed. Autogenous cancellous bone graft was harvested from the proximal humerus and placed within the metatarsal wound. Once a healthy granulation tissue bed was noted to cover the bone graft, a meshed full thickness skin graft was placed. To our knowledge, this is the first report of the Papineau technique being used for this purpose in a dog.  相似文献   

9.
To clarify the role of fibronectin (FN) during the early period of feather development, reconstituted skin consisting of intact epithelium and isolated mesenchymal cells from embryonal chick skin was used. In early feather development, FN was localized around mesenchymal cells of the dermal condensation. Isolated mesenchymal cells had associated with FN on their surfaces. FN on the cell surface dissociated following EDTA treatment, and EDTA‐treated cells re‐associated with exogenous FN. The intact epithelium also bound to exogenous FN at the placode. When FN‐associated or FN‐reassociated mesenchymal cells were used, the reconstituted skin formed feather rudiments only at the positions where the epithelial placode existed originally, and the locality of tenascin transferred from the placode to the mesenchyme during the period of feather bud formation. However, in reconstituted skin using FN‐dissociated mesenchymal cells, feather rudiments did not form. Additionally, the epithelial placodes disappeared, and tenascin was distributed uniformly on the surface of the epithelium and not localized in the mesenchyme. These findings suggest that FN associated on the surfaces of mesenchymal cells maintains the functions of mesenchymal cells as dermal condensation and mediates epithelial‐mesenchymal interactions during the early period of feather development. The results also suggest that reconstituted skin is a useful tool for functional studies on the extracellular matrix.  相似文献   

10.

Background

Pinnipeds have a thick blubber layer and may have difficulty maintaining their body temperature during hot weather when on land. The skin is the main thermoregulatory conduit which emits excessive body heat.

Methods

Thorough evaluation of the skin histology in three pinniped species; the California sea lion-Zalophus californianus, the Pacific harbor seal-Phoca vitulina richardsi, and the Northern elephant seal-Mirounga angustirostris, was conducted to identify the presence, location and distribution of skin structures which contribute to thermoregulation. These structures included hair, adipose tissue, sweat glands, vasculature, and arteriovenous anastomoses (AVA). Thermal imaging was performed on live animals of the same species to correlate histological findings with thermal emission of the skin.

Results

The presence and distribution of skin structures directly relates to emissivity of the skin in all three species. Emissivity of skin in phocids (Pacific harbor and Northern elephant seals) follows a different pattern than skin in otariids (California sea lions). The flipper skin in phocids tends to be the most emissive region during hot weather and least emissive during cold weather. On the contrary in otariids, skin of the entire body has a tendency to be emissive during both hot and cold weather.

Conclusion

Heat dissipation of the skin directly relates to the presence and distribution of skin structures in all three species. Different skin thermal dissipation patterns were observed in phocid versus otariid seals. Observed thermal patterns can be used for proper understanding of optimum thermal needs of seals housed in research facilities, rescue centers and zoo exhibits.  相似文献   

11.
Secondary bacterial infection is a frequent complication in lesional skin of dogs with immunomodulatory‐responsive lymphocytic–plasmacytic pododermatitis (ImR‐LPP). However, the influence of skin pH and temperature in determining the composition of the cutaneous microflora at lesional sites has not been investigated. The association between ImR‐LPP and pedal skin temperature, pH and Staphylococcus pseudintermedius isolates was thus evaluated. Temperature and pH were measured in 20 dogs with ImR‐LPP and in 30 clinically healthy control dogs, and S. pseudintermedius was cultured from interdigital and palmoplantar swabs in both groups and scored semi‐quantitatively for bacterial growth. In the ImR‐LPP group, mean skin pH was slightly, but significantly, higher at both interdigital and palmoplantar sites. Staphylococcus pseudintermedius was isolated more frequently, and scores for bacterial growth were also significantly higher. However, mean skin temperatures were not significantly different from those in the control group. The isolation of S. pseudintermedius was significantly associated with ImR‐LPP, with the single exception of isolates on Columbia blood agar from the palmoplantar region. However, pH and temperature were not significantly associated with the disease, and were not associated with the isolation of S. pseudintermedius at most sites sampled. Staphylococcus pseudintermedius was not isolated from all feet sampled in dogs with ImR‐LPP. Taken together, these data would suggest that S. pseudintermedius infection is most likely to be a secondary phenomenon in dogs with ImR‐LPP, and that changes in skin pH and temperature are not significant risk factors for this disease.  相似文献   

12.
Reasons for performing the study: Equine hoof canker is a chronic proliferative pododermatitis of as yet unknown aetiology. Like equine sarcoid disease, canker is a therapy‐resistant disorder characterised by hyperkeratosis, acanthosis and a marked tendency to recur. Hypothesis: There is an association of sarcoid‐inducing bovine papillomaviruses of types 1 and 2 (BPV‐1, BPV‐2) with hoof canker disease. Methods: Using PCR‐based techniques, we assessed canker tissue, intact skin and/or peripheral blood mononuclear cells (PBMCs) of 25 canker‐affected horses for the presence of sarcoid‐associated BPV‐1 and ‐2. Results: Conventional PCR revealed BPV‐1/‐2 DNA in 24/24 canker, 12/13 skin and 10/11 PBMC DNA isolates. Using inverse PCR, full‐length BPV episomes were detected in 1/5 canker specimens. Sequencing of viral early and late genes amplified from canker, intact skin and PBMC DNA of 2 cases revealed an overall identity of 98% to BPV‐1. Viral DNA loads amounted to ≤16 copies per cell in canker tissue and intact skin, and to ≤0.35 copies per PBMC, as determined by quantitative PCR. Using RT‐PCR, the viral major oncogene E5 was shown to be transcribed in 2/4 canker tissue specimens and 5/7 PBMC isolates. Immunocapture PCR from 7 canker and 6 skin extract supernatants revealed capsomere‐associated viral DNA in one canker and one skin sample. Hoof tissue, skin and PBMCs collected from 13 individuals with no signs of canker or BPV‐related malignancies scored negative throughout the experiments. Conclusion: These findings suggest that the observed presence of BPV‐1/‐2 in canker‐affected horses is not coincidental but indicative of an active contribution to hoof canker disease. Potential relevance: The use of antivirals and/or immune modulators may help improving canker therapy.  相似文献   

13.
ABSTRACT: The objective of the current study was to investigate (i) the outcome of experimentally induced Escherichia coli mastitis in primiparous cows during early lactation in relation with production of eicosanoids and inflammatory indicators, and (ii) the validity of thermography to evaluate temperature changes on udder skin surface after experimentally induced E. coli mastitis. Nine primiparous Holstein Friesian cows were inoculated 24 ± 6 days (d) after parturition in both left quarters with E. coli P4 serotype O32:H37. Blood and milk samples were collected before and after challenge with E. coli. The infrared images were taken from the caudal view of the udder following challenge with E. coli. No relationship was detected between severity of mastitis and changes of thromboxane B2 (TXB2), leukotriene B4 (LTB4) and lipoxin A4 (LXA4). However, prostaglandin E2 (PGE2) was related to systemic disease severity during E. coli mastitis. Moreover, reduced somatic cell count (SCC), fewer circulating basophils, increased concentration of tumor necrosis factor-α (TNF-α) and higher milk sodium and lower milk potassium concentrations were related to systemic disease severity. The thermal camera was capable of detecting 2-3°C temperature changes on udder skin surface of cows inoculated with E. coli. Peak of udder skin temperature occurred after peak of rectal temperature and appearance of local signs of induced E. coli mastitis. Although infrared thermography was a successful method for detecting the changes in udder skin surface temperature following intramammary challenge with E. coli, it did not show to be a promising tool for early detection of mastitis.  相似文献   

14.
Background – Seborrhoea is a clinical condition resulting in excessive lipid and/or scale on the skin and is a common and important skin disease of dogs. However, there is little information on the skin surface lipid composition of dogs with seborrhoea. Hypothesis/Objectives – To compare skin surface lipid profiles in normal and seborrhoeic shih tzu dogs. Methods – Fourteen client‐owned dogs (seven seborrhoeic and seven normal) were investigated. Lipids in sebaceous glands (SGs) were extracted from homogenized tissues of SG hyperplasia. Surface lipid was collected by tape stripping [stratum corneum (SC)‐enriched fraction] and acetone‐wetted cotton swab (acetone‐extracted fraction). Lipids in SGs, SC‐enriched fractions and acetone‐extracted fractions were evaluated by high‐performance thin‐layer chromatography. Results – Lipids in SGs mainly consisted of cholesterol esters, wax esters and triglycerides, whereas lipids in the SC‐enriched fraction mainly consisted of ceramides. The acetone‐extracted fraction contained a mixture of lipid classes recognized in SG‐ and SC‐enriched fractions. In seborrhoeic dogs, concentrations of wax esters and triglycerides in the acetone‐extracted fraction were significantly higher than in control dogs (P = 0.0285). Amounts of total ceramides (in micrograms) per milligram of SC were not significantly different between the two groups (P = 0.5204). Interestingly, two unknown ceramide fractions, which accounted for 20% of the total ceramides, were recognized exclusively in seborrhoeic dogs. Conclusions and clinical importance – These results provide evidence that the skin surface lipid profiles are altered in shih tzu dogs with seborrhoea.  相似文献   

15.
草地覆盖度测算方法研究进展   总被引：7，自引：4，他引：3  
地覆盖度作为一个重要的生态学参数被用在许多气候模型和生态模型中,测算是否精准,很大程度上决定了相关科学研究的精度。归纳了草地覆盖度测算的多种方法,整合了众多学者对草地覆盖度测算方法分类的认识差异,重点针对广泛使用的遥感技术,按照遥感的基本原理对诸多遥感估算法重新归类,理清了遥感估算草地覆盖度的基本思路。同时,分析了各种草地覆盖度测算方法的机理、优缺点和适用范围,为草地覆盖度研究方法选择提供理论依据,最后指出了草地覆盖度测算的发展趋势和研究重点。  相似文献   

16.
Background –  Adult stem cells come from many sources and have the capacity to differentiate into many cell types, including those of the skin. The most commonly studied stem cells are those termed mesenchymal stem cells (MSCs), which are easily isolated from bone marrow and adipose tissue. Mesenchymal stem cells are known to produce a wide array of cytokines that modulate the regeneration process. The ease of collection, propagation and use of these MSCs in therapy of traumatic, ischaemic and immune‐mediated skin conditions is emerging. Approach and evidence –  In traumatic and ischaemic skin damage, MSCs are used in tissue‐engineered skin and by direct injection into damaged tissue. For immune‐mediated diseases, systemic administration of stem cells can modulate the immune system. The earliest clinical work has been with autologous stem cell sources, such as adipose tissue and bone marrow. In immune‐mediated diseases, the MSCs are used to downregulate production of inflammatory cytokines and to block T‐cell activation. Cells are generally given intravenously. Multiple sclerosis, rheumatoid arthritis and lupus have been successfully treated in human clinical trials. Mesenchymal stem cells can also stimulate resident local cells, such as keratinocytes and progenitor cells, to proliferate, migrate and repair skin injury and disease. Looking ahead –  The discovery of the MSC in adipose tissue has spawned a global effort to utilize these cells in therapy of a wide range of diseases of the skin. Reconstructive surgery, scar blocking and resolution and skin regeneration have all been shown to be possible in human and animal studies.  相似文献   

17.
Infrared temperature measurement equipment (IRTME) is gaining popularity as a diagnostic tool for evaluating human and animal health. It has the prospect of reducing subject stress and disease spread by being implemented as an automatic surveillance system and by a quick assessment of skin temperatures without need for restraint or contact. This review evaluates studies and applications where IRTME has been used on pigs. These include investigations of relationships between skin, ambient and body temperatures and applications for detecting fever, inflammation, lesions, ovulation, and stress as well as for meat quality assessment. The best skin locations for high correlation between skin temperature and rectal temperature are most likely thermal windows such as ear base, eye region and udder. However, this may change with age, stressors, and biological state changes, for example, farrowing. The studies performed on pigs using IRTME have presented somewhat discrepant results, which could be caused by inadequate equipment, varying knowledge about reliable equipment operation, and site-specific factors not included in the assessment. Future focus areas in the field of IRTME are suggested for further development of new application areas and increased diagnostic value in the porcine and animal setting in general.  相似文献   

18.
In order to conserve and culture the cichlid fish Archocentrus nigrofasciatus, more information about its reproductive biology and its larval behavior and morphogenesis is necessary. Currently, temperatures ranging from 21 to 27 °C are used in ornamental aquaculture hatcheries. Lower temperatures are preferred to reduce the costs of water heating, and 23 °C is usually the selected temperature. However, there is limited information on culturing protocols for ornamental species and most of the information generated on this topic remains scarce. Thus, the present study examines the morphological development of Archocentrus nigrofasciatus during the yolk‐sac period up to the age of 100 h post‐hatching in relation to 2 temperature regimes used in ornamental aquaculture: a temperature of 27 °C (thermal optimum) and a decreased temperature of 23 °C (thermal tolerance). The results of this study suggest that the 27 °C temperature generates intense morphological changes in yolk‐sac development in a shorter period. This has advantages as it reduces the time of yolk‐sac larval development, and, thus, minimizes the transition phase to exogenous feeding and maximizes the efficiency at which yolk is converted into body tissues. The present paper provides necessary information to produce freshwater ornamental fish with better practices so as to increase larval survival and capitalize on time for growth.  相似文献   

19.
基于无人机的高寒草甸地表温度监测及影响因素研究   总被引：1，自引：0，他引：1  
地表温度直接影响地表感热、潜热及辐射能量传输过程，是研究寒区植被生态水文过程的重要参数。以疏勒河源区高寒草甸为研究对象，利用无人机搭载普通及热红外相机获取6块样地植被盖度及地表温度数据，用以评估热红外相机在高寒草甸地表温度监测中的应用精度，分析高寒草甸地表温度变化特征，并结合气象因子及植被盖度数据，探究地表温度的影响因素。结果表明：热红外影像地表温度与地面实测值具有较高一致性（R2 ≈ 0.75），平均误差5 ℃以内；高寒草甸地表温度在9： 00-18： 00时段内表现为快速升温达到峰值继而波动下降的趋势，观测期内（7月4日-8月17日）未表现出显著日际变化趋势；气象因子中，太阳辐射和空气温度与地表温度呈显著正相关，起到增温作用，而空气湿度抑制地表增温，表现为显著负相关；连续降水降低裸土温度，植被覆盖度与地表温度呈现出正相关变化趋势。无人机热红外遥感技术可以快速、精准获取高分辨率地表温度数据，为高寒草甸干旱监测、土壤水分及蒸散发等反演提供数据支持。  相似文献   

20.
Hepatocutaneous syndrome (HS) is an uncommon skin disorder that occurs in conjunction with liver disease and is diagnosed based on decreased plasma concentrations of amino acids and the histopathology of skin lesions. The survival period generally is <6 months. A 10‐year‐old castrated male Maltese dog was presented for evaluation of lethargy, polyuria, polydipsia, and skin lesions including alopecia, erythema, and crusts. Based on increased liver enzyme activity, low plasma amino acid concentrations, and findings from liver cytology and skin biopsy, the dog was diagnosed with HS. In addition to administration of antioxidants, hepatoprotective agents, and amino acids IV, allogenic adipose tissue‐derived mesenchymal stem cells were infused 46 times over a 30‐month period: 8 times directly into the liver parenchyma guided by ultrasonography and the remainder of the times into peripheral veins. After commencing stem cell therapy, the dog's hair re‐grew and the skin lesions disappeared or became smaller. During ongoing management, the patient suddenly presented with anorexia and uncontrolled vomiting, and severe azotemia was observed. The dog died despite intensive care. On necropsy, severe liver fibrosis and superficial necrolytic dermatitis were observed. The dog survived for 32 months after diagnosis. A combination of amino acid and stem cell therapy may be beneficial for patients with HS.  相似文献   

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