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81.
Josephine E. Booth Kevin J. Gaston Karl L. Evans Paul R. Armsworth 《Biological conservation》2011,144(11):2728-2732
Wildlife viewing recreation offers conservationists opportunities for education and generating revenue but can also have detrimental ecological impacts. To manage these opportunities and impacts effectively, a better understanding is needed of what people value in wildlife viewing events. We examine the relationship between species rarity and value for wildlife viewing recreation. We undertook visitor counts of birdwatchers attending rare (vagrant) bird sightings and collected home postcodes to assess the distances these individuals travelled to achieve these sightings. We also undertook visitor counts at common bird viewing locations for comparison. We regressed birdwatcher numbers against rarity, site protection status, time the bird had been on site and day of the week when the count took place. We undertook these analyses for rare bird sightings only, using a continuous measure of rarity, and for both rare and common species combined, using a categorical rarity index. Species rarity was the clearest predictor of visitor numbers in both the analyses. When studying rare birds only, we found the functional form of the relationship between rarity and visitor numbers to be inverse and asymptotic. Individuals also travelled further to see rarer species. However, while exceptional numbers of visitors attended exceptionally rare bird sightings, the marginal value of rarity appeared to be relatively low. Despite the opportunity for revenue raising and education provided by rare bird sightings, a comparison of visitor numbers at sightings inside and outside protected areas showed no evidence that managers of protected areas capitalise on these opportunities. 相似文献
82.
Bruce L. Parker Robert H. Booth James E. Bryan 《American Journal of Potato Research》1983,60(2):65-74
Population levels ofMyzus persicae (Sulzer) were studied on potato tubers in diffuse light and dark rustic storage houses in Peru. No differences in numbers of aphids/sprouted eye on potatoes infested naturally during storage in diffuse light or darkness were observed. Significantly more alate aphids were observed on tubers stored in darkness than in diffuse light storage houses. Viral transmission was occurring during the storage period. The incidence of viral transmission was not significantly influenced by storing tubers in diffuse light or dark storages. There were significantly more plants infected with virus from tubers that had not been sprayed for aphid control than from tubers that had been sprayed 相似文献
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Analgesic efficacy of an oral transmucosal spray formulation of meloxicam alone or in combination with tramadol in cats with naturally occurring osteoarthritis
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WR DuBois TM Prado JCH Ko RE Mandsager GL Morgan 《Veterinary anaesthesia and analgesia》2003,30(2):114-115
The anesthetic and cardiorespiratory effects of a low dose (LD, 0.4 mg kg?1 xylazine and 4 mg kg?1 ketamine) and a high dose (HD, 0.8 mg kg?1 xylazine and 8 mg kg?1 ketamine) of IM xylazine–ketamine combination were compared in a randomized cross‐over study using six castrated male llamas. Three llamas in each dosage group (LDT, HDT) were assigned to receive IM tolazoline (2 mg kg?1) after 30 minutes of recumbency. All IM injections were given in the semitendinosus or semimembranosus muscles. Pulse, respiratory rate, and indirect arterial blood pressure were recorded every 10 minutes, and hemoglobin oxygen saturation was recorded every 5 minutes during lateral recumbency. Samples for arterial blood gas analysis were collected 5 minutes following recumbency and every 30 minutes thereafter. Base‐to‐apex ECG was monitored continuously. Analgesia was evaluated every 5 minutes by both a 30 minutes skin pinch and a needle prick of the toe. Most llamas breathed room air throughout anesthesia. Two llamas that developed severe hypoxemia (SpO2 < 75%) received 5 minutes of nasal oxygen insufflation, but were maintained on room air for the rest of the anesthetic period. anova for repeated measures and Tukey's test were used to analyze cardiorespiratory data. Fischer's exact test was used to compare the ability of each to provide >30 minutes of lateral recumbency and analgesia. A p‐value < 0.05 was considered significant. Both dosages provided reasonably rapid induction following injection (LD: 10.8 ± 6.3 minutes; HD: 5.0 ± 1.1 minutes; p = 0.07). Duration of lateral recumbency and analgesia were 34.7 ± 6.7 and 27.3 ± 4.6 minutes, respectively, in the LDT llamas. None of the three remaining LD llamas remained in lateral recumbency for longer than 12 minutes. Duration of lateral recumbency and analgesia were 87.3 ± 18.5 and 67.7 ± 16.0 minutes, respectively, for the HD llamas that did not receive tolazoline. The HDT llamas were recumbent for a significantly shorter time (43.3 ± 0.6 minutes; p = 0.05). The ability to provide >30 minutes of recumbency and analgesia was better in the HD group (6/6) than in the LD group (2/6) (p = 0.03). No differences between dosages were seen in pulse rate, respiratory rate, or arterial pressures. No ECG abnormalities were seen. Transient hypoxemia was seen in the first 10 minutes of lateral recumbency in the HD group by both hemoglobin oxygen saturation (84 ± 9.5%) and by blood gas PaO2 (44.5 ± 5.8 mm Hg). It was concluded that the HD provided more consistent results than the LD, but induced transient hypoxemia. Tolazoline shortened the recovery time in llamas receiving the HD. 相似文献
89.
Inapparent paratuberculosis was studied in a Guernsey herd with a history of paratuberculosis (Johne's disease); the herd was maintained at between 900 and 950 cattle. Fecal specimens and intestinal tissue specimens from any of these that were slaughtered were examined culturally for the presence of Mycobacterium paratuberculosis. The reasons given for culling and slaughtering of cows from this herd were compared with infection status determined by culturing. Less than one-third of the culturally confirmed paratuberculous cattle were culled because of clinically apparent paratuberculosis. Mastitis was the reason for culling 3.6% of the non-infected cattle and 22.6% of the cattle with inapparent paratuberculosis. Infertility was also significantly higher in cows with inapparent paratuberculosis than in noninfected cows in the same herd. Separation of parturient dams and calves from the rest of the herd was shown to materially reduce the level of infection and incidence of clinical paratuberculosis. 相似文献
90.
1998年春从中国林科院的实验点甘肃临夏回族自治州林科所引入北方型美洲黑杨(P.deltoides)×青杨(P.cathayana)杂种无性系 137个,扦插在内蒙奈曼旗兴隆沼林场二分场。1998年秋选出 13个无性系,加入我地区新近确定的推广无性系──白城 41作对照,1999年建无性系测试圃,2000年春平茬,2000年秋对这 13个无性系生长量和抗性的调查与评价,以白城 41为对照,初步选择出 10个无性系,高生长较对照大 30%以上的有 4个,20%以上 5个;径生长大 50%的 3个,30%以上 2个,20%以上 4个;所有无性系的抗锈病情况都好于对照。为丰富三北地区营造杨树农田防护林品种和改善三北地区杨树品种单一的问题有望选出新无性系。 相似文献