With the evolution of the Web and development of web-based search engines, online searching has become a common method for obtaining information. Given this popularity, the question arises as to how much time people save by using search engines for their information needs compared to offline sources, as well as how online searching affects both search experiences and search outcomes. Using a random sample of queries from a major search engine and a sample of reference questions from the Internet Public Library (IPL), we conduct a real-effort experiment to compare online and offline search experiences and outcomes. We find that participants are significantly more likely to find an answer on the Web (100 %), compared to offline searching (between 87 % and 90 %). Restricting our analysis to the set of questions in which participants find answers in both treatments, a Web search takes on average 7 (9) minutes, whereas the corresponding offline search takes 22 (19) minutes for a search-engine (IPL) question. Furthermore, while raters judge library sources to be significantly more trustworthy and authoritative than the corresponding Web sources, they judge Web sources as significantly more relevant. Balancing all factors, we find that the overall source quality is not significantly different between the two treatments for the set of search-engine questions. However, for IPL questions, we find that non-Web sources are judged to have significantly higher overall quality than the corresponding Web sources. In comparison, for factual questions, Web search results are significantly more likely to be correct (66 % vs. 43 %). Lastly, post-search questionnaires reveal that participants find online searching more enjoyable than offline searching.

Temporary changes in biological state, such as hunger, can impact decision making differently for men and women. Food scarcity is correlated with a host of negative economic outcomes. Two explanations for this correlation are that hunger affects economic preferences directly or that hunger creates a mindset that focuses on scarcity management to the detriment of other decisions. To test these predictions, we conduct a lab-in-the-field experiment in a health screening clinic in Shanghai, recruiting participants who finish their annual physical exam either before or after they have eaten breakfast. We compare the hungry and sated groups on their risk, time and generosity preferences as well as their cognitive performance. Our results show that men and women respond to hunger in opposite directions, thus hunger reduces the gender gap in decision quality, risk aversion and cognitive performance, but creates one in generosity. Finally, we examine several biomarkers and find that higher blood lipid levels are correlated with greater choice inconsistency, risk aversion and generosity. We contribute to emerging insights on the biological foundations for economic preferences and outcomes.

Recently, social science research replicability has received close examination, with discussions revolving around the degree of success in replicating experimental results. We lend insight to the replication discussion by examining the quality of replication studies. We examine how even a seemingly minor protocol deviation in the experimental process (Camerer et al. in Science 351(6280):143–1436, 2016. https://doi.org/10.1126/science.aaf0918), the removal of common information, can lead to a finding of “non-replication” of the results from the original study (Chen and Chen in Am Econ Rev 101(6):2562–2589, 2011). Our analysis of the data from the original study, its replication, and a series of new experiments shows that, with common information, we obtain the original result in Chen and Chen (2011), whereas without common information, we obtain the null result in Camerer et al. (2016). Together, we use our findings to propose a set of procedure recommendations to increase the quality of replications of laboratory experiments in the social sciences.

In scientific collaborations, technologies have broadened access to scarce scientific and engineering resources. While broader access is often applauded, little attention has been focused on the problem of efficient and equitable resource allocation. This paper presents laboratory experiments designed to compare different allocation mechanisms for access to joint research facilities. Specifically, we study the Vickrey-Clarke-Groves (VCG) auction, a simultaneous ascending auction (the Resource Allocation Design, RAD), and a mechanism based on submitted rankings (Knapsack). Experimental results show that RAD and VCG are both more efficient than Knapsack, while Knapsack achieves a more equal distribution of resources than RAD or VCG. The findings highlight the need for systematic exploration of allocation mechanisms within collaboratories.

In this study, we use a novel design to test for directional behavioral spillover and cognitive load effects in a set of multiple repeated games. Specifically, in our experiment, each subject plays a common historical game with two different matches for 100 rounds. After 100 rounds, the subject switches to a new game with one match and continues playing the historical game with the other match. This design allows us to identify the direction of any behavioral spillover. Our results show that participants exhibit both behavioral spillover and cognitive load effects. First, for pairs of Prisoners’ Dilemma and Alternation games, we find that subjects apply strategies from the historical game when playing the new game. Second, we find that those who participate in a Self Interest game as either their historical or new game achieve Pareto efficient outcomes more often in the Prisoners’ Dilemma and Alternation games compared to their control counterparts. Overall, our results show that, when faced with a new game, participants use strategies that reflect both behavioral spillover and cognitive load effects.

Radiocarbon (14C) measurements play important roles in dating and tracing applications where the isotopic concentration can differ from 0.1 to 106 pMC (percent modern carbon). A liquid scintillation counter cannot provide enough sensitivity when dealing with low-concentration samples of limited amounts over a reasonable time period. Accelerator mass spectroscopy (AMS) measures low-concentrations well but must first do dilution for high-concentration samples, and suffers from high instrument and maintenance costs. Saturated absorption CAvity Ring-down spectroscopy (SCAR) has now been developed into a practical technique with performances close to AMS but at much lower costs. The dynamic range covers 1–105 pMC, and the measurement uncertainties in the range of 0.4–1 pMC can be achieved within 0.5–2.5 hr of operation time. SCAR measures CO2 gases directly without graphitization in sample preparation. The typical sample consumption is ∼1 mg of carbon mass and the time for sample preparation can be as short as 15 min. Applications of SCAR to Suess-effect evaluation, biogenic-component analysis, ancient- and modern-sample dating, food-fraud detection and medicine-metabolism study have all been demonstrated by employing a close-to-automatic sample preparation system.

The knowledge of the critical periods of crop-weed competition is crucial for designing weed management strategies in cropping systems. In the Lower Yangtze Valley, China, field experiments were conducted in 2011 and 2012 to study the effect of interference from mixed natural weed populations on cotton growth and yield and determine the critical period for weed control (CPWC) in direct-seeded cotton. Two treatments were applied: allowing weeds to infest the crop or keeping plots weed-free for increasing periods (0, 1, 2, 4, 6, 8, 10, 12, 14, and 20 weeks) after crop emergence. The results showed that mixed natural weed infestations led to 35 to 55 cm shorter cotton plants with stem diameters 10 to 13 mm smaller throughout the season, fitting well with modified Gompertz and logistic models, respectively. Season-long competition with weeds reduced the number of fruit branches per plant by 65% to 82%, decreasing boll number per plant by 86% to 96% and single boll weight by approximately 24%. Weed-free seed cotton yields ranged from 2,900 to 3,130 kg ha-1, while yield loss increased with the duration of weed infestation, reaching up to 83% to 96% compared with permanent weed-free plots. Modified Gompertz and logistic models were used to analyze the impact of increasing weed control duration and weed interference on relative seed cotton yield (percentage of season-long weed-free cotton), respectively. Based on a 5% yield-loss threshold, the CPWC was found to be from 145 growing degree days (GDD) to 994 GDD, corresponding to 14 days after emergence (DAE) to 85 DAE. These findings emphasize the importance of implementing effective weed control measures from 14 DAE to 85 DAE in the Lower Yangtze Valley, China, to prevent crop losses exceeding a 5% yield-loss threshold.

Systematically monitoring the baseline sensitivity of troublesome weeds to herbicides is crucial for the early detection of a premature market lifespan of herbicides. Florpyrauxifen-benzyl is one of the most important rice herbicides across the world, which has been used for five years in China. Barnyardgrass is one of the main targeted weed species of florpyrauxifen-benzyl. Totally 114 barnyardgrass populations were collected from rice fields in Jiangsu Province, China, and screened for susceptibility of each population to florpyrauxifen-benzyl by whole-plant bioassays. For all populations, the GR50 doses (the dose causing a 50% reduction in fresh weight of aboveground parts) of florpyrauxifen-benzyl ranged from 1.0 to 34.5 g ai ha-1, with an average of 6.8 g ai ha-1, a baseline sensitivity dose of 3.3 g ai ha-1, and a baseline sensitivity index of 34.5. Twenty-one days after treatment with florpyrauxifen-benzyl at the labeled dose (36 g ai ha-1), 90% of the barnyardgrass populations showed reductions in fresh weight of aboveground parts > 95%. Compared with the baseline sensitivity dose, 63, 44, and seven populations had no resistance (55%), low resistance (39%), and moderate resistance (6%) to florpyrauxifen-benzyl, respectively. Furthermore, the GR50 distribution of barnyardgrass populations did not show a significant correlation with city, planting methods (direct-seeding or transplanting), and rice species (ssp. indica or ssp. japonica) at the seed-collection rice fields (P > 0.05). In conclusion, florpyrauxifen-benzyl remains effective for barnyardgrass control in rice fields despite serious resistance challenges.

Based on a 4f system, a 0° reflector and a single laser diode side-pump amplifier, a new amplifier is designed to compensate the spherical aberration of the amplified laser generated by a single laser diode side-pump amplifier and enhance the power of the amplified laser. Furthermore, the role of the 4f system in the passive spherical aberration compensation and its effect on the amplified laser are discussed in detail. The results indicate that the amplification efficiency is enhanced by incorporating a 4f system in a double-pass amplifier and placing a 0° reflector only at the focal point of the single-pass amplified laser. This method also effectively uses the heat from the gain medium (neodymium-doped yttrium aluminium garnet) of the amplifier to compensate the spherical aberration of the amplified laser.

The propagation of multiple ultraintense femtosecond lasers in underdense plasmas is investigated theoretically and numerically. We find that the energy merging effect between two in-phase seed lasers can be improved by using two obliquely incident guiding lasers whose initial phase is $\pi$ and $\pi /2$ ahead of the seed laser. Particle-in-cell simulations show that due to the repulsion and energy transfer of the guiding laser, the peak intensity of the merged light is amplified by more than five times compared to the seed laser. The energy conversion efficiency from all incident lasers to the merged light is up to approximately 60$\%$. The results are useful for many applications, including plasma-based optical amplification, charged particle acceleration and extremely intense magnetic field generation.

Although it is well established that gestational diabetes mellitus (GDM) is associated with fetal overgrowth in singleton pregnancies, little is known about its role in twins. We aimed to explore the relationship between GDM and the longitudinal fetal growth in twin pregnancies. This was a retrospective matched cohort study of GDM and non-GDM twin pregnancies delivered ≥36 weeks without other complications. All the women performed ≥3 ultrasounds after 22 weeks. Linear mixed models (LMMs) were used to explore the relationships between longitudinal fetal growth trajectories and GDM. Group-based trajectory modeling (GBTM) and generalized estimating equation (GEE) were applied to identify the latent growth patterns and investigate their relationships with GDM. In total, 215 GDM and 645 non-GDM twins were included, the majority of the patients did not require medication therapy (n = 202, GDMA1). LMM revealed that, compared with non-GDM, GDM was associated with an average increase in fetal weight of 4.36 g (95% CI [1.25, 7.48]) per week. GBTM and GEE further revealed that GDM increased the odds of fetal weight trajectory to nearly 40% of the total fetal weight trajectory, classified into the high-speed group (aOR = 1.39, 95% CI [1.03, 1.88]), associating with a 49.44 g (95% CI [11.41, 87.48]) increase in birth weight. Subgroup analysis revealed that all these differences were only significant among the GDMA1 pregnancies (p < .05). GDM (GDMA1) is significantly associated with an increase in fetal weight during gestation in twin pregnancies. However, this acceleration is mild, and its significance requires further exploration.

Using the syntactic priming paradigm, this study investigated abstract syntactic knowledge of Chinese transitive structures (i.e., subject-verb-object [SVO], BA, and BEI) in deaf children with cochlear implants (CIs). Specifically, we focused on the differences in the development of various syntactic structures (within CI children and compared with their typically hearing children) and the possible individual differences during this process. Results showed that both CI and hearing children exhibited structural priming for all syntactic structures (i.e., SVO, SbaOV structure [agent-patient ordering], and ObeiSV structure [patient-agent ordering]) after comprehending and repeating the prime sentence regardless of verb repetition. However, verb repetition induced an intense abstract priming effect in CI children but not hearing children, with the lexical boost effect more significant for SVO and BA structures. In addition, CI children’s working memory capability modulated the production of the BA structure but not SVO and BEI structures.

In this paper, we study the rapid transition in Richtmyer–Meshkov instability (RMI) with reshock through three-dimensional double-layer swirling vortex rings. The rapid transition in RMI with reshock has an essential influence on the evolution of supernovas and the ignition of inertial confinement fusion, which has been confirmed in numerical simulations and experiments in shock-tube and high-energy-density facilities over the past few years. Vortex evolution has been confirmed to dominate the late-time nonlinear development of the perturbed interface. However, few studies have investigated the three-dimensional characteristics and nonlinear interactions among vortex structures during the transition to turbulent flows. The coexistence of co-rotating and counter-rotating vortices is hypothesized to induce successive large-scale strain fields, which are the main driving sources for rapid development. The three-dimensional effect is reflected in the presence of local swirling motion in the azimuthal direction, and it decreases the translation velocity of a vortex ring. Large-, middle- and small-scale strain fields are employed to describe the development process of RMI with reshock, e.g. vorticity deposited by the reshock, formation of the coexistence of the co-rotating and counter-rotating vortices, iterative cascade under the amplification of the strain fields and viscous dissipation to internal energy. This provides theoretical suggestions for designing practical applications, such as the estimation of the hydrodynamic instability and mixing during the late-time acceleration phase of the inertial confinement fusion.

The ubiquitous marine radiocarbon reservoir effect (MRE) constrains the construction of reliable chronologies for marine sediments and the further comparison of paleoclimate records. Different reference values were suggested from various archives. However, it remains unclear how climate and MREs interact. Here we studied two pre-bomb corals from the Hainan Island and Xisha Island in the northern South China Sea (SCS), to examine the relationship between MRE and regional climate change. We find that the MRE from east of Hainan Island is mainly modulated by the Southern Asian Summer Monsoon-induced precipitation (with 11.4% contributed to seawater), rather than wind induced upwelling. In contrast, in the relatively open seawater of Xisha Island, the MRE is dominated by the East Asian Winter Monsoon, with relatively more negative (lower) ΔR values associated with high wind speeds, implying horizontal transport of seawater. The average SCS ΔR value relative to the Marine20 curve is –161±39 14C years. Our finding highlights the essential role of monsoon in regulating the MRE in the northern SCS, in particularly the tight bond between east Asian winter monsoon and regional MRE.

The Internet presents today’s researchers with unprecedented opportunities to conduct field experiments. Using examples from Economics and Computer Science, we present an analysis of the design choices, with particular attention to the underlying technologies, in conducting online field experiments and report on lessons learned.