Developing an economic estimation system for vertical farms

The concept of vertical farming is nearly twenty years old, however, there are only a few experimental prototypes despite its many advantages compared to conventional agriculture. Significantly, financial uncertainty has been identified as the largest barrier to the realization of a ‘real’ vertical farm. Some specialists have provided ways to calculate costs and return on investment, however, most of them are superficial with calculations based on particular contextual circumstances. To move the concept forwards a reliable and flexible estimating tool, specific to this new building typology, is clearly required. A computational system, software named VFer, has therefore been developed by the authors to provide such a solution. This paper examines this highly flexible, customised system and results from several typical vertical farm configurations in three mega-cities (Shanghai, London and Washington DC) are used to elucidate the potential economic return of vertical farms

Moment of Inertia for Axisymmetric Neutron Stars in the Standard-Model Extension

We develop a consistent approach to calculate the moment of inertia (MOI) for axisymmetric neutron stars (NSs) in the Lorentz-violating Standard-Model Extension (SME) framework. To our knowledge, this is the first relativistic MOI calculation for axisymmetric NSs in a Lorentz-violating gravity theory other than deformed, rotating NSs in the General Relativity. Under Lorentz violation, there is a specific direction in the spacetime and NSs get stretched or compressed along that direction. When a NS is spinning stationarily along this direction, a conserved angular momentum and the concept of MOI are well defined. In the SME framework, we calculate the partial differential equation governing the rotation and solve it numerically with the finite element method to get the MOI for axisymmetric NSs caused by Lorentz violation. Besides, we study an approximate case where the correction to the MOI is regarded solely from the deformation of the NS and compare it with its counterpart in the Newtonian gravity. Our formalism and the numerical method can be extended to other theories of gravity for static axisymmetric NSs.Comment: 9 pages, 3 figure

GW150914 and gravitational-wave astronomy

On September 14, 2015, the first detection of gravitational waves at the advanced Laser Interferometer Gravitational- Wave Observatory (LIGO) detectors, in the United States, marked the beginning of "gravitational-wave astronomy", that opens a new window looking into the violent sides of our Universe. It is very promising that at other wavelengths detections of gravitational waves with various space-based and ground-based observatories will show up in the near future of this century. These observatories include space-based laser interferometer antennas, pulsar timing arrays, cosmic microwave background satellites, etc

A sex-role-preference model for HIV transmission among men who have sex with men in China

Background: Men who have sex with men (MSM) are much more likely to be infected with HIV than the general population. China has a sizable population of MSM, including gay, bisexual men, money boys and some rural workers. So reducing HIV infection in this population is an important component of the national HIV/AIDS prevention and control program. Methods: We develop a mathematical model using a sex-role-preference framework to predict HIV infection in the MSM population and to evaluate different intervention strategies. Results: An analytic formula for the basic reproduction ratio R0 was obtained; this yields R0 = 3.9296 in the current situation, so HIV will spread very fast in the MSM population if no intervention measure is implemented in a timely fashion. The persistence of HIV infection and the existence of disease equilibrium (or equilibria) are also shown. We utilized our model to simulate possible outcomes of antiretroviral therapy and vaccination for the MSM population. We compared the effects of these intervention measures under different assumptions about MSM behaviour. We also found that R0 is a decreasing function of the death rate of HIV-infected individuals, following a power law at least asymptotically. Conclusion: HIV will spread very fast in the MSM population unless intervention measures are implemented urgently. Antiretroviral therapy can have substantial impact on the reduction of HIV among the MSM population, even if disinhibition is considered. The effect of protected sexual behaviour on controlling the epidemic in the MSM population largely depends on the sex-ratio preference of different sub-populations

Is Graph Structure Necessary for Multi-hop Question Answering?

Recently, attempting to model texts as graph structure and introducing graph neural networks to deal with it has become a trend in many NLP research areas. In this paper, we investigate whether the graph structure is necessary for multi-hop question answering. Our analysis is centered on HotpotQA. We construct a strong baseline model to establish that, with the proper use of pre-trained models, graph structure may not be necessary for multi-hop question answering. We point out that both graph structure and adjacency matrix are task-related prior knowledge, and graph-attention can be considered as a special case of self-attention. Experiments and visualized analysis demonstrate that graph-attention or the entire graph structure can be replaced by self-attention or Transformers.Comment: 6 pages, to appear at EMNLP 202

An Experimental Study on Lateral Acceleration of Cars in Different Environments in Sichuan, Southwest China

In view of the tremendous improvements in the dynamic performance of automobiles and changes in the composition of drivers over the past several decades, it is valuable to examine the distribution of automobile’s lateral acceleration in new environments. The lateral accelerations, speeds, and trajectory curvatures of a passenger car on twelve highways with different design speeds and topographies were obtained. By synchronizing, matching, and counting, the distribution of the lateral acceleration was obtained, and the level of driving comfort was estimated. The 10th, 15th, 50th, 85th, and 90th percentile values of the lateral acceleration on three road types (six-lane road, four-lane road, and two-lane road) were found. Combined with scatter diagrams of the lateral acceleration over the curvature, the negative correlation between the lateral acceleration and the curvature was analyzed and interpreted. In addition, regression models of the lateral acceleration with the curvature for the three kinds of roads were established. Based on scatter diagrams of the lateral acceleration over the speed, regression models of the average ay depending on the speed and the 85th percentile ay depending on the speed of passenger cars and buses were established. The research provides calculation parameters and a control basis for operating speed prediction, pavement material design, and maximum and minimum limit value determination for the superelevation ratios and curve radii

Broader HIV-1 neutralizing antibody responses induced by envelope glycoprotein mutants based on the EIAV attenuated vaccine

<p>Abstract</p> <p>Background</p> <p>In order to induce a potent and cross-reactive neutralizing antibody (nAb), an effective envelope immunogen is crucial for many viral vaccines, including the vaccine for the human immunodeficiency virus (HIV). The Chinese equine infectious anemia virus (EIAV) attenuated vaccine has controlled the epidemic of this virus after its vaccination in over 70 million equine animals during the last 3 decades in China. Data from our past studies demonstrate that the Env protein of this vaccine plays a pivotal role in protecting horses from both homologous and heterogeneous EIAV challenges. Therefore, the amino acid sequence information from the Chinese EIAV attenuated vaccine, in comparison with the parental wild-type EIAV strains, was applied to modify the corresponding region of the envelope glycoprotein of HIV-1 CN54. The direction of the mutations was made towards the amino acids conserved in the two EIAV vaccine strains, distinguishing them from the two wild-type strains. The purpose of the modification was to enhance the immunogenicity of the HIV Env.</p> <p>Results</p> <p>The induced nAb by the modified HIV Env neutralized HIV-1 B and B'/C viruses at the highest titer of 1:270. Further studies showed that a single amino acid change in the C1 region accounts for the substantial enhancement in induction of anti-HIV-1 neutralizing antibodies.</p> <p>Conclusions</p> <p>This study shows that an HIV envelope modified by the information of another lentivirus vaccine induces effective broadly neutralizing antibodies. A single amino acid mutation was found to increase the immunogenicity of the HIV Env.</p