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1.

Aim

Savanna biomes cover around 20% of land surfaces, yet the origins and processes that have shaped their biodiversity remain understudied. Here, we assess the timing of diversification and how patterns of genetic diversity vary along an aridity gradient in specialized saxicoline gecko clades (Oedura spp.) from the tropical savannas of northern Australia.

Location

Australian Monsoonal Tropics (AMT), Kimberley region (Western Australia).

Methods

We compiled mitochondrial and nuclear data for two Kimberley endemic lizard clades (Oedura filicipoda/murrumanu and O. gracilis), and allied non‐Kimberley taxa (O. marmorata complex). Species delimitation methods were used to identify evolutionary lineages, Maximum‐likelihood and Bayesian phylogenetic methods were employed to assess relationships and diversification timeframes, and rainfall data and range sizes were tested for correlations.

Results

Phylogenetic analyses of cryptic or recently discovered lineage diversity revealed late‐Miocene to early‐Pliocene crown ages. Microendemism and diversity were highest in high‐rainfall regions, while the most widespread lineages occurred in the central and south‐east Kimberley, and showed evidence of introgression with parapatric lineages.

Main conclusions

The initial diversification in both clades was broadly concordant with global climatic events linked to the expansion of savanna biomes in the lateMiocene. Higher endemism in mesic and refugial areas suggests long histories of localized persistence, while wider distributions and evidence of introgression suggest a dynamic history at the arid‐monsoonal interface.  相似文献   
2.
The remote Pitcairn Group in the South Pacific Ocean comprises a volcanic island (Pitcairn Island), two low coral atolls (Oeno, Ducie) and a raised coralline island (Henderson Island). The geological history of these islands, on anomalously thin oceanic lithosphere, is related to the development of two subparallel island chains (Oeno-Henderson-Ducie; Pitcairn) associated with intra-Pacific plate 'hotspot' activity; the surface manifestation of this activity has been partly determined by structural lineations in the plate inherited from past plate history. The climate of the Pitcairn Islands is determined by the position of the subtropical high pressure system and the South Pacific Convergence Zone. Variations in the strength of this atmospheric circulation system, measured by changes in the Southern Oscillation index of pressure difference, provide a partial explanation of the long-term variability of mean annual rainfall at Pitcairn Island. Knowledge of past climates in the Pitcairn Group remains speculative. Maps of the Pitcairn Islands and a report of climate at Henderson Island (2/91-1/92) are included in the paper.  相似文献   
3.
We present a synthesis of the palaeolimnological and palaeoclimatic reconstructions of four sites in Colombia. The record from Lake El Caimito, the westernmost site on the Pacific Coast, dates from the Late Holocene and shows lacustrine sedimentation frequently interrupted by fluvial pulses. These pulses probably reflect periods of increased precipitation related to La Niña phases. East of El Caimito site is the Patía swamp, situated between the Western and Central Andean Cordilleras. The Patía records the dynamics of forest expansion/reduction and changes in water levels. Although the climatic signal of the Patia core is difficult to reconstruct, there is a clear increase in humidity in the Mid-Holocene. The Fúquene Lake record, on the Eastern Andean Cordillera, records dry and cold conditions during the Late Pleistocene, very humid conditions for the early Mid-Holocene, and dry conditions during the mid-Late Holocene. Las Margaritas site, on the eastern savannas, records dry conditions during the Early Holocene and overall humid conditions for the Mid- and Late Holocene. Climate conditions from the Fuquene and Las Margaritas sites seem to reflect the Holocene movements of the Intertropical Convergence Zone (ITCZ); the latter site being more affected by humidity coming from the Amazon region.  相似文献   
4.
Aim  We analysed the geographical distributions of species of Buprestidae (Coleoptera) in Mexico by means of a panbiogeographical analysis, in order to identify their main distributional patterns and test the complex nature of the Mexican Transition Zone, located between the Nearctic and Neotropical regions.
Location  Mexico.
Methods  The geographical distributions of 228 species belonging to 33 genera of Buprestidae were analysed. Localities of the buprestid species were represented on maps and their individual tracks were drawn. Based on a comparison of the individual tracks, generalized tracks were detected and mapped. Nodes were identified as the areas where generalized tracks converged.
Results  Thirteen generalized tracks were obtained: one was restricted to the Mexican Transition Zone and five to the Neotropical region (Antillean and Mesoamerican dominions), a further two occurred in both the Nearctic region (Continental Nearctic dominion) and the Mexican Transition Zone, and a further five in both the Neotropical region (Mesoamerican dominion) and the Mexican Transition Zone. Seven nodes were identified at the intersections of the generalized tracks – in the Mesoamerican dominion (Mexican Pacific Coast, Mexican Gulf and Chiapas biogeographical provinces) and the Mexican Transition Zone (Trans-Mexican Volcanic Belt, Balsas Basin and Sierra Madre Oriental biogeographical provinces).
Main conclusions  We conclude that the geographical distribution of Buprestidae is mainly Neotropical, corresponding to the Mesoamerican dominion and the Antillean dominion of the Neotropical region, and the Mexican Transition Zone. Most of the generalized tracks and nodes correspond to the Mexican Transition Zone, thus confirming its complex nature. We suggest that the nodes we have identified could be particularly important areas to choose for conservation prioritization.  相似文献   
5.
The disruption of circadian rhythms following time‐zone transitions gives rise to the syndrome of jet lag. The power of some of the symptoms of jet lag to predict the amount of jet lag measured at the same and at different times of the day has been investigated. Eleven healthy subjects were studied in an Isolation Unit for two days after a simulated flight from the UK to Beijing (8 time zones to the east). At six time‐points (08:30, 11:00, 14:00, 17:00, 20:00, and 23:00 h), the subjects recorded their jet lag, and the differences from “normal” (that is, from days in which there is no jet lag) of alertness, hunger, indigestion, concentration, motivation, and irritability. They recorded at 08:30 h the type of food they had eaten since rising at 08:00 h and, at the other times, the type of food eaten in the last three hours. Assessments were made by visual analogue scales or, in the case of type of food, by a nominal scale. Following the time‐zone transition, the adjustment of meals appeared to be complete almost immediately. Jet lag and its symptoms were present during both experimental days. Jet lag tended to rise during the course of the daytime, accompanied by falls in alertness, motivation, and concentration. Correlation matrices between jet lag and each of the other variables were produced, using lags between the variable (from up to 5 time‐points before the assessment of jet lag to 5 time‐points afterwards) and pooling the results from both days. These matrices indicated that significant correlations existed only between jet lag and alertness, concentration, and motivation, and then only when these other variables were assessed at the same time as jet lag or 1 or 2 time‐points earlier. Jet lag was then treated as the dependent variable and the symptoms as covariates in analysis of covariances (ANCOVAs), with the days treated as a random effect. This analysis enabled the significance of potential predictors of jet lag, together with their β‐coefficients (the relationship between a unit change of each significant predictor and the change in jet lag), to be calculated. Falls in alertness and motivation were significant predictors of increased jet lag, provided that they were measured at the same time, when they accounted for about 50% of the jet lag; when measured at other time‐points, they did not act as significant predictors. It is concluded that the amount of jet lag varies during the course of the day and that it can be predicted from contemporaneous assessments of alertness and motivation—but not from assessments made at other times of the day, nor from other variables that are symptoms of jet lag, even though these other variables are significantly increased. In considering the results of this and our previous study, we reiterate the view that the exact meaning of “jet lag” is complex and that the particular combination of factors that contribute to it might vary with the time of day that the assessment is made. Inferences about any decrements due to time‐zone transitions cannot be made reliably at times of the day that differ from the time when jet lag is assessed.  相似文献   
6.
Esophageal cancer is common in China. There is a lack of treatment strategies for metastatic esophageal cancer (MEC) after radical surgery on the primary tumor. Cryoablation is an attractive option because tumor necrosis can be safely induced in a minimally invasive manner. This study assessed its therapeutic effect in MEC after failure of radical surgery. One hundred and forty patients met the inclusion criteria from May, 2003 to March, 2011. Comprehensive cryotherapy of multiple metastases was performed on 105 patients; 35 received chemotherapy. No severe complications occurred during or after cryoablation. Overall survival (OS) was assessed according to therapeutic protocol, pathologic type, treatment timing and number of procedures. The OS of patients who received comprehensive cryoablation (44 ± 20 months) was significantly longer than that of those who underwent chemotherapy (23 ± 24 months; P = 0.0006). In the cryotherapy group, the OS for squamous cell carcinoma (45 ± 19 months) was longer than that for adenocarcinoma (33 ± 18 months; P = 0.0435); the OS for timely cryoablation (46 ± 19 months) was longer than that for delayed cryoablation (33 ± 20 months; P = 0.0193); the OS for multiple cryoablation (50 ± 17 months) was longer than that for single cryoablation (37 ± 20 months; P = 0.0172); and the OS for cryo-immunotherapy (56 ± 17 months) was longer than that for cryoablation alone (39 ± 19 months; P = 0.0011). Thus, comprehensive cryotherapy may have advantages over chemotherapy in the treatment of MEC and, in patients with squamous cell carcinoma, supplementary immunotherapy and timely and multiple cryoablation may be associated with a better prognosis.  相似文献   
7.
PTEN gene (phosphatase and tensin homolog deleted on chromosome ten, MIM 601628) is a tumor suppressor gene implicated in PTEN hamartoma tumor syndromes (PHTS) including Cowden syndrome, Bannayan–Riley–Ruvalcaba syndrome and Proteus-like syndrome. PTEN mutations have been more recently reported in children with macrocephaly and autism spectrum disorders or mental retardation, without other symptoms of PHTS. Although tumor risk has not been evaluated in these patients and their relatives, the same surveillance as for Cowden syndrome is usually proposed. We report a family including patients carrying a novel PTEN mutation and presenting with a mild phenotype consisting of macrocephaly, hypotonia during the first year of life and mild learning disabilities, without autistic features. None of these patients exhibited PTHS-related symptoms such as tumors, lipomas, vascular malformations or pigmented macules of the glans penis. This report raises the question of extending the indications of PTEN mutation screening to familial macrocephaly with learning disabilities. Detection of a mutation in this family led to difficult questions about surveillance, genetic counseling and familial information since the mother declined tumor screening and disclosure of genetic risk information to at-risk relatives.  相似文献   
8.
A pilot-scale Sequencing Batch Reactor was operated during 307 days in order to treat swine slurry characterized by its high variable composition: organic and nitrogen applied loading rates and C/N ratio were 1.4–6.3 kg CODs/(m3 d), 0.5–2.5 kg N/(m3 d) and 1.9–9.4 g CODs/(g N), respectively. Aerobic granules successfully developed in the reactor and their physical properties remained rather stable despite the feeding composition variability. Organic and ammonia removal efficiency reached 61–73% and 56–77%, respectively, however ammonia was mainly oxidized to nitrite. The reactor had a good biomass retention capacity to select for granular biomass. However, its efficiency to retain the solids present in the feeding was low. Aerobic granulation in SBR systems appears as an interesting alternative to treat slurry in small livestock facilities where the implementation of anaerobic digestion systems is not a feasible option or the removal of nitrogenous compounds is required.  相似文献   
9.
Data on 455 female and 464 male subjects from the World Aquatic Sports Championships in Perth, Australia, in 1991, were used to demonstrate the similarity of variability of 35 anthropometric items and support the use non-gender-biased proportionality models. This paper is a preliminary report on a study of allometry, dimensionality and human proportionality inspired by Professor Otto Eiben.  相似文献   
10.
F/F牙形刺灭绝事件以后,牙形刺很快进入复苏期(王成源、Ziegler,2004)。有关法门期牙形刺的辐射,在国内外的文献中还没有详细的论述或论证。本文基于以前对广西桂林垌村和龙门剖面的牙形刺集群灭绝与复苏的研究,2003年又在垌村剖面加密采样,重点是研究F/F事件后,牙形刺由复苏到辐射阶段的特征,探索牙形刺何时和如何由复苏期进化到辐射期。本文的材料主要是依据华南的资料,特别是本文作者研究多年的垌村剖面的资料。牙形刺的灭绝与复苏是以法门期最主要的属Palmatolepis为主线,在种一级的水平上确定的。法门期牙形刺的辐射同样是以Palmatolepis属内种一级的水平上讨论的。同时也涉及到其它属。本文首次明确提出:牙形刺在晚triangularis带就进入辐射期,因为正是从晚triangularis带,Palmatolepis的minuta,werneri,sandbergi,perlobata,cf.regularis,subperlobata,tenupunctata7个重要种群开始出现,并在法门期中期达到辐射期的高峰。  相似文献   
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