Testing mechanisms of compensatory fitness of dioecy in a cosexual world

Questions: All else being equal, populations of dioecious species with a 50:50 sex ratio have only half the effective reproductive population size of bisexual species of equal abundance. Consequently, there is a need to explain how dioecious and bisexual species coexist. Increased mean individual seed mass, fecundity, and population density have all been proposed as attributes of unisexual individuals or populations that may contribute to the persistence or resilience of dioecious species. To date, no studies have compared sympatric dioecious and cosexual species with respect to all three components of fitness. In this study, we sought evidence for these compensatory advantages (higher seed mass, greater seed production per unit basal area, and higher population density) in dioecious species. Location: Five 20–25 ha forest dynamic plots spanning a latitudinal gradient in China, including two temperate, two subtropical, and one tropical forest. Methods: We used a phylogenetically corrected generalized linear modelling approach to assess the phylogenetic dependence and joint evolution of sexual system, seed mass and production, and ecological abundances among 48–333 species and 32,568–136,237 individuals per forest. Results: Across all five forests, we detected no consistent advantage for dioecious relative to sympatric cosexual species with respect to mean individual seed mass, seed production or the density of stems in any size class. Conclusions: Our study suggests that seed traits may provide compensatory mechanisms in some forests, but most often the coexistence of sexual systems cannot be explained by advantages of dioecy related to seed quality and demographic parameters. Future investigations of the factors that promote coexistence may increase our understanding by expanding the search to include attributes such as lifespan and tolerance or resistance to herbivores

A hand shape recognizer from simple sketches

Hand shape recognition is one of the most important techniques used in human-computer interaction. However, it often takes developers great efforts to customize their hand shape recognizers. In this paper, we present a novel method that enables a hand shape recognizer to be built automatically from simple sketches, such as a 'stick-figure' of a hand shape. We introduce the Hand Boltzmann Machine (HBM), a generative model built upon unsupervised learning, to represent the hand shape space of a binary image, and formulate the user provided sketches as an initial guidance for sampling to generate realistic hand shape samples. Such samples are then used to train a hand shape recognizer. We evaluate our method and compare it with other state-of-the-art models in three aspects, namely i) its capability of handling different sketch input, ii) its classification accuracy, and iii) its ability to handle occlusions. Experimental results demonstrate the great potential of our method in real world applications. © 2013 IEEE.published_or_final_versio

Ultrafast fluorescent decay induced by metal-mediated dipole-dipole interaction in two-dimensional molecular aggregates

Two-dimensional molecular aggregate (2DMA), a thin sheet of strongly interacting dipole molecules self-assembled at close distance on an ordered lattice, is a fascinating fluorescent material. It is distinctively different from the single or colloidal dye molecules or quantum dots in most previous research. In this paper, we verify for the first time that when a 2DMA is placed at a nanometric distance from a metallic substrate, the strong and coherent interaction between the dipoles inside the 2DMA dominates its fluorescent decay at picosecond timescale. Our streak-camera lifetime measurement and interacting lattice-dipole calculation reveal that the metal-mediated dipole-dipole interaction shortens the fluorescent lifetime to about one half and increases the energy dissipation rate by ten times than expected from the noninteracting single-dipole picture. Our finding can enrich our understanding of nanoscale energy transfer in molecular excitonic systems and may designate a new direction for developing fast and efficient optoelectronic devices.Comment: 9 pages, 6 figure

Benefit Assessment of the Integrated Demand Management Concept for Multiple New York Metroplex Airports

Benefits of the Integrated Demand Management (IDM) concept were assessed utilizing a newly developed automated simulation capability called Traffic Management Initiative Automated Simulation (TMIAutoSim). The IDM concept focuses on improving traffic flow management (TFM) by coordinating the FAAs strategic Traffic Flow Management System (TFMS) with its more tactical Time-Based Flow Management (TBFM) system. The IDM concept leverages a new TFMS capability called Collaborative Trajectory Options Program (CTOP) to strategically pre-condition traffic demand flowing into a TBFM-managed arrival environment, where TBFM is responsible for tactically managing traffic by generating precise arrival schedules. The IDM concept was developed over a multi-year effort, focusing on solving New York metroplex airport arrival problems. TMIAutoSim closely mimics NASAs high-fidelity simulation capabilities while enabling more data to be collected at higher speed. Using this new capability, the IDM concept was evaluated using realistic traffic across various weather scenarios. Six representative weather days were selected after clustering three months of historical data. For those selected six days, Newark Liberty International Airport (EWR) and LaGuardia Airport (LGA) arrival traffic scenarios were developed. For each selected day, the historical data were analyzed to accurately simulate actual operations and the weather impact of the day. The current day operations and the IDM concept operations were simulated for the same weather scenarios and the results were compared. The selected six days were categorized into two groups: clear weather for days without Ground Delay Programs (GDP) and convective weather for days with GDP and significant weather around New York metroplex airports. For the clear weather scenarios, IDM operations reduced last minute, unanticipated departure delays for short-haul flights within TBFM control boundaries with minimal to no impact on throughput and total delay. For the convective weather scenarios, IDM significantly reduced delays and increased throughput to the destination airports

Multiparty multilevel watermarking protocol for digital secondary market based on iris recognition technology

Background: In order to design secure digital right management architecture between different producers and different consumers, this paper proposes a multiparty and multilevel watermarking protocol for primary and secondary market. Comparing with the traditional buyer-seller watermarking protocols, this paper makes several outstanding achievements. Method: First of all, this paper extends traditional buyer-seller two-party architecture to multiparty architecture which contains producer, multiply distributors, consumers, etc. Secondly, this paper pays more attention on the security issues, for example, this paper applies iris recognition technology as an advanced security method. Conclusion: Finally, this paper also presents a second-hand market scheme to overcome the copyright issues that may happen in the real world. © 2017 Bentham Science Publishers

Fabrication of Micro-Perforated Panel (MPP) sound absorbers using Digital Light Processing (DLP) 3D printing technology

The fabrication of Micro-Perforated Panels (MPPs) still constitutes a challenge to the acoustic materials industry because it usually requires expensive manufacturing techniques to obtain holes of submillimetre size. In this context, the rise of additive manufacturing or 3D printing (3DP) technologies over the last years has paved the way for the design and development of new materials at the microscopic scale. Among these, Digital Light Processing (DLP) technology emerges as an excellent option due to its advantages in terms of printing speed and higher accuracy when compared to traditional additive manufacturing technologies. This work demonstrates the capacity of DLP technology to fabricate MPPs and explores its design possibilities by using different exposure times in the manufacturing process to attain different hole sizes. To this end, several MPP specimens were fabricated and tested when used as a resonator system in an impedance tube setup to determine their sound absorption performance, the experimental data showing a good agreement when compared to predictions obtained using the Maa model. Preliminary results highlight the potential capabilities of DLP and encourage its use in the design stage of these acoustics resonator systems.The conception of this research work took place at the Department of Mechanical Engineering at the Massachusetts Institute of Technology with support from the University of Alicante (Grant ACIE20-04)

Impact of Online Renting on Software Piracy

Online rental of software is emerging as a new way of dissemination for several major software firms. Compared to outright selling, the renting scheme delivers the software as a service instead of a physical good. Hence, users cannot privately make copies for resale in the market. We investigate the impact of the renting mechanism on software piracy and pricing in a two-period model whereby a piracy market is present in the second period. We develop and compare models with or without renting. Our analysis shows that renting reduces social welfare but helps to increase a vendor’s profit under certain conditions. We also assess the difference in outcomes in the presence of network effect

Prevalence of childhood epilepsy in Canada.

Few data exist on the frequency and burden of childhood epilepsy in Canada and on the impact in the general population. We have assessed the point prevalence of childhood epilepsy in Canada. We analyzed data from the National Longitudinal Survey of Children and Youth (N=20 025 for Cycle 2, and N= 31 960 for cycle 3). Each cycle was collected over a two year period (2: 1996-1997, 3: 1998-1999). In the survey the following specific question was asked to the person most knowledgeable in the household: Does the child have any of the following long-term conditions that have been diagnosed by a health professional? The list of responses included Epilepsy and certain co-morbid conditions. In addition, a subsequent question identified whether the condition was treated by means of a specific anticonvulsant medication. (anticonvulsants or anti-epileptic pills?). Prevalence was based on the national standard population at the time of each survey. In Cycle 2, 80 of 20 025 subjects from 0 to 13 years old were described to have the diagnosis of epilepsy, yielding a weighted point prevalence of 4.03 per 1 000. In Cycle 3 161 of 31 960 children from 0 to 15 were described as having epilepsy, yielding a weighted point prevalence of 5.26 per 1 000. The rate of epilepsy was higher for males and increases with age. The overall rates for this age cohort are consistent with those obtained in other developed countries and seem to coincide with rates for youth and adults in Canada