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121.
Abstract

Design, synthesis and properties of catalytic NAs for targeting MDR1 mRNA are reported.  相似文献   
122.
《Autophagy》2013,9(6):985-986
Autophagy is a cellular pathway that degrades damaged organelles, cytosol and microorganisms, thereby maintaining human health by preventing various diseases including cancers, neurodegenerative disorders and diabetes. In autophagy, autophagosomes carrying cellular cargoes fuse with lysosomes for degradation. The proper autophagosome-lysosome fusion is pivotal for efficient autophagy activity. However, the molecular mechanism that specifically directs the fusion process is not clear. Our study reported that lysosome-localized TECPR1 (TECtonin β-Propeller Repeat containing 1) binds the autophagosome-localized ATG12–ATG5 conjugate and recruits it to autolysosomes. TECPR1 also binds PtdIns3P in an ATG12–ATG5-dependent manner. Consequently, depletion of TECPR1 leads to a severe defect in autophagosome maturation. We propose that the interaction between TECPR1 and ATG12–ATG5 initiates the fusion between the autophagosome and lysosome, and TECPR1 is a TEthering Coherent PRotein in autophagosome maturation.  相似文献   
123.
China's remarkable economic growth in the last 3 decades has brought about big improvements in quality of life while simultaneously contributing to serious environmental problems. The aim of all economic activities is, ultimately, to provide the population with products and services. Analyzing environmental impacts of consumption can be valuable for illuminating underlying drivers for energy use and emissions in society. This study applies an environmentally extended input‐output analysis to estimate household environmental impact (HEI) of urban Beijing households at different levels of development. The analysis covers direct and indirect energy use and emissions of carbon dioxide (CO2), sulfur dioxide (SO2), and nitrogen oxide (NOx). On the basis of observations of how HEI varies across income groups, prospects for near‐future changes in HEI are discussed. Results indicate that in 2007, an urban resident in Beijing used, on average, 52 gigajoules of total primary energy supply. The corresponding annual emissions were 4.2 tonnes CO2, 27 kilograms SO2, and 17 kilograms NOx. Of this, only 18% to 34% was used or emitted by the households directly. While the overall expenditure elasticity of energy use is around 0.9, there is a higher elasticity of energy use associated with transport. The results suggest that significant growth in HEI can be expected in the near future, even with substantial energy efficiency improvements.  相似文献   
124.
Resource availability constrains the life history strategies available to organisms and may thereby limit population growth rates and productivity. We used this conceptual framework to explore the mechanisms driving recently reported negative relationships between fish productivity and dissolved organic carbon (DOC) concentrations in lakes. We studied populations of bluegill (Lepomis macrochirus) in a set of lakes with DOC concentrations ranging from 3 to 24 mg/L; previous work has demonstrated that primary and secondary productivity of food webs is negatively related to DOC concentration across this gradient. For each population, we quantified individual growth rate, age at maturity, age‐specific fecundity, maximum age, length‐weight and length‐egg size relationships, and other life history characteristics. We observed a strong negative relationship between maximum size and DOC concentration; for instance, fish reached masses of 150 to 260 g in low‐DOC lakes but <120 g in high‐DOC lakes. Relationships between fecundity and length, and between egg size and length, were constant across the DOC gradient. Because fish in high‐DOC lakes reached smaller sizes but had similar fecundity and egg size at a given size, their total lifetime fecundity was as much as two orders of magnitude lower than fish in low‐DOC lakes. High DOC concentrations appeared to constrain the range of bluegill life history strategies available; populations in high‐DOC lakes always had low initial growth rates and high ages at maturity, whereas populations in low‐DOC showed higher variability in these traits. This was also the case for the intrinsic rates of natural increase of these populations, which were always low at the high end of the DOC gradient. The potentially lower capacity for fish populations in high‐DOC lakes to recover from exploitation has clear implications for the sustainable management of recreational fisheries in the face of considerable spatial heterogeneity and ongoing temporal change in lake DOC concentrations.  相似文献   
125.
Freshwater ecosystem service is essential to human’s survival and development. Many studies have documented the spatial differences in the supply and demand of ecosystem services and proposed the concept of ecosystem services flows. However, few studies characterize freshwater ecosystem service flow quantitatively. Therefore, our paper aims to quantify the effects of freshwater ecosystem service flow on downstream areas. We developed a freshwater ecosystem service flow model and applied it in the Beijing–Tianjin–Hebei (BTH) region, China, for the year of 2000, 2005, and 2010. We assessed the regional water security with an improved freshwater security index by integrating freshwater service provision, consumption and flow; and found that most areas of the BTH region (69.2%) were affected by upstream freshwater flows. The areas achieving water security in the region also expanded to 66.9%, 66.1%, and 71.3%, which were 6.4%, 6.8% and 5.7% increments compared to no-flow situation, in 2000, 2005 and 2010, respectively. Setting quota for human water consumption is suggested to further improve water security. These results highlight the need to fully understand the connections between distant freshwater ecosystem service provision and local freshwater ecosystem service consumption. This approach may also help managers to choose more sustainable strategies for critical freshwater resource management across different regions.  相似文献   
126.
The increased persistence of predator–prey systems when interactions are distributed through the space has been acknowledged by both empirical and theoretical studies. One salient feature of predator–prey interactions in heterogeneous space, for example, is the existence of cycles with reduced amplitude when compared with a homogeneous landscape. Although the role of spatial interactions in shaping the dynamics of predator–prey systems has been extensively studied, still very few works have focused on the effects of habitat loss and fragmentation on these systems. In this work, we study the population dynamics of a predator–prey system in a single finite habitat with flux at the boundaries. Species movement and growth are described through a reaction–diffusion model with Rosenzweig–MacArthur type local interactions. Conforming with the existing literature, we find that the reduction of habitat size, or increasing of species movement rates equivalently, has the potential to decrease the amplitude of oscillations and even bring the system to a steady coexistence equilibrium above a threshold. We observe, however, situations in which this trend is reversed. This occurs when species movement rates and response at patch boundaries interact to induce non-trivial patterns of species distributions. These distributions are characterized by anti-correlation between predator and prey, creating then spatial refugia for prey. Our results highlight the role of population loss through habitat boundaries in determining the dynamics of predator–prey interactions.  相似文献   
127.
以湛江地区6个主要菠萝品种巴厘、卡因、台农17号、台农16号、粤脆、香水为对象,研究菠萝的组分在品种间的差异及其与菠萝蛋白酶的产率和酶活力之间的相关性,结果显示,不同的菠萝品种间,各组分的含量以及蛋白酶的得率及酶活有显著差异。菠萝果皮和果肉的不同生长部位的蛋白含量、酶活力及酶得率有显著差异。酶得率与蛋白及纤维素含量呈显著正相关;酶活力与糖酸比、得汁率、纤维素含量及Zn含量呈显著负相关,蛋白含量、纤维素含量、糖酸比、得汁率是衡量菠萝产酶品质的重要指标。  相似文献   
128.
ABSTRACT Populations of feral domestic cats have increased throughout the United States, affecting wildlife and warranting attention from a variety of management agencies. This contentious issue requires a greater understanding of public attitudes and preferences for population control. We used data from a 2004 mail survey of Illinois, USA, homeowners’ attitudes towards wildlife and conservation to investigate support for the trap-neuter–release (TNR) of feral cats and to examine factors (demographic, experience, and wildlife values orientations) that may influence preference for TNR as a management option. Age, gender, and wildlife rights values orientations were significant predictors of preference for TNR, while negative experiences with feral cats were correlated with preferences for management options other than TNR. Investigations of public perceptions of feral cat management can help wildlife managers understand the growing public debate regarding feral cat management and provide appropriate input and educational materials regarding cat management and wildlife.  相似文献   
129.
130.
Shelly Volsche 《Anthrozo?s》2018,31(3):367-377
The American Pet Products Association reports a decade-long increase of pet spending, estimated to reach over $69 billion in 2017. In some cases, these owners apply traditional parenting practices while nurturing their pets. Relatedly, a growing number of pet owners identify themselves as “pet parents.” This study is the first known work to investigate how identity plays a role in the growing population of pet parents. While previous research into the pet parenting phenomenon has sought to quantify the demographics, spending, and frequency of this population, less work seeks to understand what pet parenting looks like in practice. Sampling a population of childfree pet parents, the current study utilized semi-structured interviews and identified two common themes in their daily practice of the identity: 1) Despite the use of parent–child terms and strategies, childfree pet parents are acutely aware of the differences between raising children and raising pets, and 2) pet parents ascribe agency to their pet, identifying individual pet wants and needs to fulfill. This may further inform future research on human–animal relationships by establishing a human identity that connects directly to pet practices in the United States, asking us to consider the lived experiences of this growing population and their pets including spending, lifestyle, and attachment concerns.  相似文献   
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