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In this paper, we consider the closed spacelike solution to a class of Hessian quotient equations in de Sitter space. Under mild assumptions, we obtain an existence result using standard degree theory based on a priori estimates.
By
Zhihe Zhang, Chengdu Research Base of Giant Panda Breeding,
Anju Zhang, Chengdu Giant Panda Breeding Research Foundation,
Rong Hou, Chengdu Research Base of Giant Panda Breeding,
Jishan Wang, Chengdu Research Base of Giant Panda Breeding,
Guanghan Li, Chengdu Giant Panda Breeding Research Foundation,
Lisong Fei, Chengdu Zoo,
Qiang Wang, Chengdu Zoo,
Kati I. Loeffler, National Zoological Park,
David E. Wildt, National Zoological Park,
Terry L. Maple, Center for Conservation & Behaviour,
Rita Mcmanamon, Zoo Atlanta,
Susie Ellis, Conservation International
The giant panda is one of the national treasures of China. Many factors, related primarily to increased human activity, have caused a marked decline and geographic fragmentation of the wild population. To preserve this endangered species, the Chinese government, in partnership with many nongovernmental organisations (inside and outside China), has invested significant human and material resources to benefit in situ conservation. These collective efforts have resulted in the establishment of more than 40 nature reserves in southwest China in the provinces of Sichuan, Gansu and Shaanxi.
Giant pandas have been sporadically maintained in captivity since the Han Dynasty (206 BC to AD 226) (see Chapter 1). However, it was not until the 1940s that there was serious interest in exhibiting the species in China. It took more than 20 years of giant panda husbandry experience to produce the first cub in captivity, at the Beijing Zoo in 1963. Much progress has been made in the subsequent years in understanding basic giant panda biology and making it possible for the species to reproduce consistently in captivity. This chapter reviews the brief history and significance of ex situ breeding efforts for the giant panda.
THE SIGNIFICANCE OF EX SITU BREEDING PROGRAMMES FOR THE GIANT PANDA
The giant panda is particularly vulnerable to external pressures, in part because of an inherently slow rate of reproduction.
By
Jogayle Howard, National Zoological Park,
Zhihe Zhang, Chengdu Research Base of Giant Panda Breeding,
Desheng Li, China Conservation and Research Center for the Giant Panda,
Yan Huang, China Conservation and Research Center for the Giant Panda,
Rong Hou, Chengdu Research Base of Giant Panda Breeding,
Guanghan Li, Chengdu Giant Panda Breeding Research Foundation,
Meijia Zhang, Chengdu Research Base of Giant Panda Breeding,
Zhiyong Ye, Chengdu Research Base of Giant Panda Breeding,
Jinguo Zhang, Beijing Zoo,
Shiqiang Huang, Beijing Zoo,
Rebecca Spindler, Toronto Zoo,
Hemin Zhang, China Conservation and Research Center for the Giant Panda,
David E. Wildt, National Zoological Park
The goal of the giant panda ex situ breeding programme is to produce healthy, genetically diverse and reproductively sound offspring. However, reproduction in this species has been poor, in part, due to lack of male libido or aggressive behaviours towards conspecific females. Although giant panda breeding facilities have made progress in producing more surviving young, only about 29% of captive male giant pandas have ever sired offspring (Lindburg et al., 1998), and most of these males were wild born. Of the 104 giant pandas in the ex situ population in China in 1996 (at the time of the first masterplanning meeting in China; Zheng et al., 1997; see also Chapter 2), there were 33 adult males of reproductive age (6–26 years old). Only five (15.2%) had ever mated naturally and sired young. This was the main reason for ‘male reproduction’ being a primary target of the Biomedical Survey conducted under the umbrella of the Conservation Breeding Specialist Group (CBSG) (see Chapter 2).
We had three goals, the first being to measure the presence or absence of any obvious physiological or anatomical abnormalities. The second was to learn more about species reproductive biology, specifically comparing males of different ages, successful versus unsuccessful breeders and wild-born versus captive born. Our approach also allowed a third opportunity: studies that would enhance our understanding on how better to use male gametes (sperm) to advance genetic management (see Chapter 21). In this case, our focus was on:
sperm morphology and acrosomal integrity;
testes development during the breeding season;
[…]
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