Spatial Pattern of Construction Land Distribution in Bays along the Coast of Vietnam

Current studies of urban spatial morphology have rarely focused on the particularity of coastal cities, such as sea–land gradient features and bay types. In this paper, we provide a method to analyze the spatial and vertical distribution of construction land in the bay area and discuss the influence of bay type on the distribution characteristics. Landscape indexes and a clustering algorithm were used to identify the spatial pattern of construction land distribution. Strip division was used to analyze the landscape features of construction land in the sea–land direction. We established eight large bays in Vietnam as the study area. According to the formation and geomorphology of the bay, the eight bays were divided into five types: delta bay, lagoon bay, structural bay, bedrock erosion-stacking bay and estuary bay. The construction land data were generated from Landsat images captured in 1988 and 2015 or so. The study effectively identified five spatial patterns of construction land distribution in bays without prior knowledge. Danang Bay (a bedrock erosion-stacking bay) had a typical high intensity-high concentration pattern, and Hai Loc Bay (a delta bay) had a typical high intensity-low concentration pattern. In the sea–land gradient, the proportions of construction land in the 0–2 km zone were greatest. In Danang Bay, the proportion generally decreased in the sea–land direction; while in Hai Loc Bay, the proportion increased.

Circumventing the natural, frequent oestrogen waves of the female cheetah (Acinonyx jubatus) using oral progestin (Altrenogest)

Cheetah are induced ovulators, experiencing short, variable oestrogen waves year-round. Exogenous gonadotrophin administration induces ovulation, but success is variable and often improves if ovaries are quiescent. After affirming the presence of short-term oestrogenic waves, we examined the effect of the timing of administration of exogenous equine and human chorionic gonadotrophins (eCG–hCG) within the oestrogen concentration pattern on subsequent follicle development and oocyte and corpus luteum quality. We also investigated ovarian suppression using an oral progestin (Altrenogest, 7 days) and assessed whether Altrenogest moderated adrenal activity by reducing glucocorticoid metabolites. All cheetahs exhibited short (every ~7–10 days), sporadic, year-round increases in faecal oestradiol punctuated by unpredictable periods (4–10 weeks) of baseline oestradiol (anoestrous). Gonadotrophin (eCG–hCG) efficacy was not affected by oestradiol ‘wave’ pattern if administered ≥3 days after an oestrogen peak. Such cheetahs produced normative faecal progestagen patterns and higher numbers (P < 0.06) of mature oocytes than females given gonadotrophins ≤2 days after an oestradiol peak. Altrenogest supplementation expanded the interval between oestradiol peaks to 12.9 days compared with 7.3 days without progestin pretreatment. Altrenogest-fed females excreted less (P < 0.05) glucocorticoid metabolites than non-supplemented counterparts. Results show that Altrenogest is effective for suppressing follicular activity, may contribute to reduced glucocorticoid production and may result in more effective ovulation induction via gonadotrophin therapy.