An Experimental Investigation of the Effect of Bacillus megaterium on Apatite Dissolution

Field observations suggest that some mineral dissolution rates can be enhanced by microbial activity indirectly, without direct contact with the mineral surface. A series of apatite dissolution experiments was performed to better understand this rate enhancement process. Far-from equilibrium abiotic apatite dissolution rates, measured in mixed-flow reactors at 25°C were enhanced by increasing concentration of aqueous organic acids and decreasing aqueous phosphate activity, demonstrating the existence of indirect pathways for microbial rate enhancement. Further apatite dissolution experiments were performed in closed-system reactors in the presence of Bacillus megaterium , a common heterotrophic aerobe. Experiments were designed to allow the bacteria to be either in direct contact or indirect contact with the apatite; in the latter case, the microbes were physically separated from the apatite using dialysis bags. Apatite dissolution in indirect contact with Bacillus megaterium was 50 to 900% faster than abiotic controls. Bacterial rate enhancement was, however, 3 to over 10 times lower when Bacillus megaterium was in direct contract versus indirect contact with the apatite surfaces. These results show that (1) bacteria can accelerate rates without being in physical contact with the dissolving mineral, and (2) microbially mediated dissolution may be less effective when bacteria are in direct contact with mineral surfaces. Supression of mineral dissolution is interpreted to stem from the preferential colonization of reactive sites on the mineral surface.     

The Influence of Host Plant Extrafloral Nectaries on Multitrophic Interactions: An Experimental Investigation

A field experiment was conducted with outplantings of the native perennial shrub Senna mexicana var. chapmanii in a semi-natural area adjacent to native pine rockland habitat in southern Florida. The presence of ants and the availability of extrafloral nectar were manipulated in a stratified random design. Insect communities were monitored and recorded over a period of six months with a view to addressing three main questions. Do ants provide biotic defense against key herbivores on S. chapmanii? Is the presence of ants on S. chapmanii mediated by EFN? Finally, are there ecological costs associated with the presence of ants on S. chapmanii, such as a reduction in alternative predator or parasitoid numbers? Herbivores on S. chapmanii included immature stages of three pierid butterflies, and adult weevils. Eight species of ants were associated with the plants, and other predators included spiders, ladybugs, wasps, and hemipterans. Parasitic, haemolymph-sucking midges (Ceratopogonidae) and parasitoid flies were also associated with the caterpillar herbivores, and possibly the extrafloral nectaries of the plants. The presence of ants did not appear to influence oviposition by butterflies, as numbers of lepidopterans of all developmental stages did not differ among treatments. Significantly more late instar caterpillars, however, were observed on plants with ants excluded, indicating that ants remove small caterpillars from plants. Substantially more alternative predators (spiders, ladybugs, and wasps) were observed on plants with ants excluded. Rates of parasitization did not differ among the treatments, but there were substantially fewer caterpillars succumbing to virus among those collected from control plants.We provide a rare look at facultative ant-plant mutualisms in the context of the many other interactions with which they overlap. We conclude that ants provide some biotic defense against herbivores on S. chapmanii, and plants benefit overall from the presence of ants, despite negative impacts on non-ant predators.     

The Influence of Emotion on Keyboard Typing: An Experimental Study Using Auditory Stimuli

In recent years, a novel approach for emotion recognition has been reported, which is by keystroke dynamics. The advantages of using this approach are that the data used is rather non-intrusive and easy to obtain. However, there were only limited investigations about the phenomenon itself in previous studies. Hence, this study aimed to examine the source of variance in keyboard typing patterns caused by emotions. A controlled experiment to collect subjects’ keystroke data in different emotional states induced by International Affective Digitized Sounds (IADS) was conducted. Two-way Valence (3) x Arousal (3) ANOVAs was used to examine the collected dataset. The results of the experiment indicate that the effect of arousal is significant in keystroke duration (p < .05), keystroke latency (p < .01), but not in the accuracy rate of keyboard typing. The size of the emotional effect is small, compared to the individual variability. Our findings support the conclusion that the keystroke duration and latency are influenced by arousal. The finding about the size of the effect suggests that the accuracy rate of emotion recognition technology could be further improved if personalized models are utilized. Notably, the experiment was conducted using standard instruments and hence is expected to be highly reproducible.     

The Effect of Priming on Perceptions of Dog Breed Traits

ABSTRACT

This study examined whether priming cues embedded in mediastyle presentations shaped people's perceptions of specific dog breeds, and in particular, the German shepherd dog (GSD). Two hundred and four adult females were exposed to one of two types of media-style presentation (stories or pictures). Half of the participants in each condition were exposed to versions designed to portray the GSD in a positive light; the remainder to stimuli developed to present the same breed in a negative light. Participants subsequently rated six individual breeds of dog, including the target breed, on a number of traits (e.g., “friendliness,” “aggression”). Analysis revealed a significant effect of priming on people's perceptions of the GSD. Participants exposed to the negative stimuli perceived this breed as significantly less approachable, and more dangerous and aggressive, than those exposed to the positive stimuli. Priming did not influence the participants' perceptions of other breeds, even those often regarded in a negative light, although there was some evidence of breed-related category-based stereotyping. Overall, results suggest that people's perceptions of dog breeds can be influenced by verbal and visual representations. The results have implications for how dogs are portrayed in the media and other publically available sources of information.     

Transamination: An Exercise in Experimental Control

In the light of the misunderstandings detected in the area of water transport a model based on the physical sciences was designed in the form of an animated film. Pupils taught by this means were able to pick their way through the proposed hierarchy of ideas to construct for themselves a shorter (self-consistent) route than that envisaged by the designers. This route formed a useful ‘core’ approach to the topic which would be sufficient for O-level, but would be weak in its predictive properties and form an unsatisfactory base for further study.     

Effect of Immune Priming on Borna Disease

Borna disease virus (BDV) is a neurotropic virus with a broad host and geographic range. Lewis rats were immunized against BDV with a recombinant vaccinia virus expressing the BDV nucleoprotein and were later infected with BDV to evaluate protection against Borna disease (BD). Relative to animals that were not immunized, immunized animals had a decreased viral burden after challenge with infectious virus, more marked inflammation, and aggravated clinical disease. These data suggest that a more robust immune response in Borna disease can reduce viral load at the expense of increased morbidity.     

Effects of Cognitive Load on Trusting Behavior – An Experiment Using the Trust Game

Last decades have witnessed a progressing decline of social trust, which has been predominantly linked to worsening economic conditions and increasing social inequality. In the present research we propose a different type of explanation for the observed decline – cognitive load related to technological development and the accelerating pace of modern life. In an experimental study participants played the trust game while performing one of two different secondary tasks – listening to a disturbing noise or memorizing a sequence of characters – or with no additional task in the control condition. Results show that in both cognitive load conditions participants expressed significantly less trust in the trust game than in case of no cognitive load. Additionally, when cognitive resources were limited, participants’ behavior was more impulsive than when their resources were fully available.     

Effect of An Educational Inpatient Diabetes Management Program on Medical Resident Knowledge and Measures of Glycemic Control: A Randomized Controlled Trial

ObjectiveTo investigate the effectiveness of an Inpatient Diabetes Management Program (IDMP) on physician knowledge and inpatient glycemic control.MethodsResidents assigned to General Internal Medicine inpatient services were randomized to receive the IDMP (IDMP group) or usual education only (nonIDMP group). Both groups received an overview of inpatient diabetes management in conjunction with reminders of existing order sets on the hospital Web site. The IDMP group received print copies of the program and access to an electronic version for a personal digital assistant (PDA). A Diabetes Knowledge Test (DKT) was administered at baseline and at the end of the 1-month rotation. The frequency of hyperglycemia among patients under surveillance by each group was compared by using capillary blood glucose values and a dispersion index of glycemic variability. IDMP users completed a questionnaire related to the program.ResultsTwenty-two residents participated (11 in the IDMP group and 11 in the non-IDMP group). Overall Diabetes Knowledge Test scores improved in both groups (IDMP: 69% ± 1.7% versus 83% ± 2.1%, P = .003; nonIDMP: 76% ± 1.2% versus 84% ± 1.4%, P = .02). The percentage of correct responses for management of corticosteroid-associated hyperglycemia (P = .004) and preoperative glycemic management (P = .006) improved in only the IDMP group. The frequency of hyperglycemia (blood glucose level > 180 mg/dL) and the dispersion index (5.3 ± 7.6 versus 3.7 ± 5.6; P = .2) were similar between the 2 groups.ConclusionAn IDMP was effective at improving physician knowledge for managing hyperglycemia in hospitalized patients treated with corticosteroids or in preparation for surgical procedures. Educational programs directed at improving overall health care provider knowledge for inpatient glycemic management may be beneficial; however, improvements in knowledge do not necessarily result in improved glycemic outcomes. (Endocr Pract. 2012;18:238-249)     

Surface Modification of Biodegradable Mg-4Zn Alloy Using PMEDM: An Experimental Investigation,Optimization and Corrosion Analysis

ObjectivesMagnesium alloys are the potential candidate for metallic implants due to their excellent mechanical characteristics, biodegradable nature, and properties similar to human bone. However, a high degradation rate is primary obstacle in implementing these alloys as biodegradable orthopedic implants. Powder-mixed electric discharge machining (PMEDM) is an emerging method of surface modification of metallic alloys that can be implemented to improve the corrosion resistance of Mg alloys. Therefore, PMEDM using zirconium (Zr) and manganese (Mn) powder particles has been proposed to modify the surface characteristics of Mg-4Zn alloy.Materials and MethodsIn the present work, Zr and Mn powders have been used in varying concentrations during PMEDM of Mg-4Zn alloy. Experiments were conducted as per mixed design L18 orthogonal array (OA). Taguchi and Grey Relational Analysis (GRA) have been used to optimize the process parameters. Analysis of response characteristics, namely material removal rate (MRR), surface roughness (SR), and thickness of the alloyed layer (TAL), has been carried out at different values of input variables (like powder additives (P_a), powder concentration (C_p), peak current (I_p), pulse on time (T_on) and duty cycle (DC)). The corrosion analysis was carried out by immersing the specimen (machined at an optimized setting) in simulated body fluid (SBF).ResultsIt is observed from the analysis that C_p, I_p, and T_on play a pivotal role in evaluating response characteristics. The favorable setting suggested by the gray approach is P_a: Zr; C_p: 2 g/l; I_p: 4A; T_on: 50 μs; DC: 80%, while responses at this setting are confirmed by confirmation experiments with MRR: 32.14 mm³/min; SR: 5.578 μm and TAL: 8.28 μm. The immersion test signifies that the corrosion rate (CR) of PMEDMed sample (3.20 mm/year) is 40.74% lesser than the corrosion rate of polished sample (5.40 mm/year).ConclusionZr powder shows better performance in terms of higher MRR, lower SR and higher TAL as compared to Mn powder during the PMEDM process. The corroded surface of polished sample exhibited larger size micro pits and cracks than the machined sample, which concluded that surface modification of MZ-4Zn alloy via PMEDM is a powerful tool to enhance its corrosion resistance.     

Experimental Invasions Using Biological Control Introductions: The Influence of Release Size on the Chance of Population Establishment

Introductions of biological control organisms offer a unique opportunity to experimentally study the process of invasion by exotic species. I used two chrysomelid beetles, Galerucella calmariensis and Galerucella pusilla, which are currently being introduced into North America for the biological control of purple loosestrife (Lythrum salicaria), to determine how the initial size of a release affects the probability that the introduced population grows and persists. I released both species into stands of their host plant at 36 sites scattered throughout central New York State using four release sizes: 20, 60, 180, and 540. I returned to these sites over the next 3 years to census the populations. For both species, the probability of population establishment increased with release size. Population growth rates also depended positively on release size. The implication from these results is that the demographic factors whose influence depends on population size or density such as demographic stochasticity, Allee effects, and genetics play important roles in the establishment of invading populations. A second set of releases was used to determine if it was at all possible for a single gravid female to found a population. Out of twenty individual females released, one female (a G. calmariensis) founded a population that persisted until the end of the study (3 generations). This revised version was published online in July 2006 with corrections to the Cover Date.     

Estimation and Inference for the Causal Effect of Receiving Treatment on a Multinomial Outcome: An Alternative Approach

Summary Recently, Cheng (2009 , Biometrics 65, 96–103) proposed a model for the causal effect of receiving treatment when there is all‐or‐none compliance in one randomization group, with maximum likelihood estimation based on convex programming. We discuss an alternative approach that involves a model for all‐or‐none compliance in two randomization groups and estimation via a perfect fit or an expectation–maximization algorithm for count data. We believe this approach is easier to implement, which would facilitate the reproduction of calculations.     

The Effect of Ginseng (The Genus Panax) on Glycemic Control: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials

Importance

Despite the widespread use of ginseng in the management of diabetes, supporting evidence of its anti-hyperglycemic efficacy is limited, necessitating the need for evidence-based recommendations for the potential inclusion of ginseng in diabetes management.

Objective

To elucidate the effect of ginseng on glycemic control in a systematic review and meta-analysis of randomized controlled trials in people with and without diabetes.

Data sources

MEDLINE, EMBASE, CINAHL and the Cochrane Library (through July 3, 2013).

Study selection

Randomized controlled trials ≥30 days assessing the glycemic effects of ginseng in people with and without diabetes.

Data extraction

Relevant data were extracted by 2 independent reviewers. Discrepancies were resolved by consensus. The Heyland Methodological Quality Score and the Cochrane risk of bias tool were used to assess study quality and risk of bias respectively.

Data synthesis

Sixteen trials were included, in which 16 fasting blood glucose (n = 770), 10 fasting plasma insulin (n = 349), 9 glycated hemoglobin (n = 264), and 7 homeostasis model assessment of insulin resistance (n = 305) comparisons were reported. Ginseng significantly reduced fasting blood glucose compared to control (MD =  −0.31 mmol/L [95% CI: −0.59 to −0.03], P = 0.03). Although there was no significant effect on fasting plasma insulin, glycated hemoglobin, or homeostasis model assessment of insulin resistance, a priori subgroup analyses did show significant reductions in glycated hemoglobin in parallel compared to crossover trials (MD = 0.22% [95%CI: 0.06 to 0.37], P = 0.01).

Limitations

Most trials were of short duration (67% trials<12wks), and included participants with a relatively good glycemic control (median HbA1c non-diabetes = 5.4% [2 trials]; median HbA1c diabetes = 7.1% [7 trials]).

Conclusions

Ginseng modestly yet significantly improved fasting blood glucose in people with and without diabetes. In order to address the uncertainty in our effect estimates and provide better assessments of ginseng''s anti-diabetic efficacy, larger and longer randomized controlled trials using standardized ginseng preparations are warranted.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01841229","term_id":"NCT01841229"}}NCT01841229     

Learning Control for Biomimetic Undulating Fins: An Experimental Study

Learning control should focus on imitating natural fish's adaptability to complex and dynamic environment to some extent, rather than mimicking streamlined shapes or specific actuators to develop more mechanical prototypes. In this paper, an experimental study on a proposed learning control of the robotic undulating fin, RoboGnilos, is suggested and explored. This study takes inspirations from biological world to practical control algorithms. In detail, an iterative learning scheme based control is studied with the cooperation of a filter to reduce the measurement noise, and a curve fitting component to keep the necessary phase difference between neighboring fin rays. Moreover, the iterative learning control algorithm is designed and implemented for practical applications. The experimental results validate that the proposed learning control can effectively improve the propulsion of RoboGnilos. For instance, the steady propulsion velocity may be enhanced by over 40% with some specified parameters.     

Subterranean Sympatry: An Investigation into Diet Using Stable Isotope Analysis

In the Western Cape three species of mole-rat occur in sympatry, however, little is known about differences in their dietary preferences. Dietary composition of the three species; the common mole-rat (Cryptomys hottentotus hottentotus), the Cape mole-rat (Georychus capensis) and the Cape dune mole-rat (Bathyergus suillus) were examined using stable isotope analysis. Blood, fur and claw samples were collected from 70 mole-rats, in addition to several potential food items, to assess food selection of the three species under natural conditions. Overall there was a significant difference in the isotopic composition (δ¹³C and δ¹⁵N) between all three species and significant differences in their diet composition. There were also significant differences between tissues in all three species suggesting temporal variation in diet. The small size and colonial lifestyle of C. h. hottentotus allows it to feed almost 100% on bulbs, while the solitary and larger species G. capensis and B. suillus fed to a greater extent on other resources such as grasses and clover. B. suillus, the largest of the species, had the most generalized diet. However, overall all species relied most heavily upon geophytes and consumed the same species suggesting competition for resources could exist. We also showed a high level of individual variation in diet choices. This was most pronounced in B. suillus and G. capensis and less so in C. h. hottentotus. We demonstrate that stable isotope analysis can successfully be applied to examine dietary patterns in subterranean mammals and provide insights into foraging patterns and dietary variation at both the inter and intra population level.     

面部表情的阈下情绪启动效应及其机制

人类大脑是否可以加工阈下情绪信息?阈下情绪启动效应为此提供了直接证据。使用视觉掩蔽和连续闪烁抑制范式,以面部表情作为启动刺激的研究发现,个体在注意和记忆、社会性评价和行为倾向中都受先前启动刺激情绪属性的影响,即表现出了阈下情绪启动效应。还有研究发现,阈下面部表情增强了个体的皮肤电导水平和心血管系统反应。而神经机制的研究发现,阈下面部表情对目标刺激的早期知觉加工和晚期情绪意义分析产生了影响,杏仁核等脑区在其中具有重要作用。情绪优先假设和感受即信息理论分别从情绪系统领域特殊性和情绪归因的角度试图阐释该效应产生的机制。在总结和分析以往研究基础上,本文对这一领域的未来研究提出了具体建议。     

The Avian Shoulder: An Experimental Approach

SYNOPSIS. This essay is in two parts. The first describes functionalstudies of the shoulder in modern vertebrates that led to theformulation of the hypotheses that motor patterns of homologousmuscles have been maintained during the evolution of the tetrapodshoulder, and that a primitive organization of the neural controlcomponents has persisted in derived groups. The second part of this essay focuses upon a longstanding questionin vertebrate evolution: what neuromuscular and musculoskeletalchanges in the tetrapod shoulder accompanied the evolution offlight in birds? The lack of empirical data on shoulder functionin extant birds limited our insight into this question, andprompted our initiation of experimental studies. Preliminarykinematics of the furcula and humerus of European starlings(Sturnus vulgaris) flying in a wind tunnel, as revealed by highspeed cineradiography, are presented. The two halves of thefurcula, which contact the coracoids dorsally, are bent laterallyduring downstroke and medially during upstroke by as much as60% of the intrafurcular resting distance. High speed film andelectromyographic studies of freeflying pigeons (Columba livia)reveal that the supracoracoideus muscle is strongly activatedduring wing elevation and, as predicted from studies of Varanusand Didelphis, an additional activation burst occurs at mid-downstrokein 48% of the recordings.     

Laser Impact on Marine Planktonic Diatoms: An Experimental Study Using a Flow Cytometry System

A flow cytometry system was used to evaluate the impact of pulsed laser irradiations from an Nd:YAG laser on two marine coastal water diatoms, Chaetoceros gracilis and Skeletonema costatum. Three flow speeds, i.e. 9, 18 and 27 ml min^{m 1} and three laser fluences, i.e. 0.025, 0.05 and 0.1 J cm^{m 2} pulse^{m 1} were tested during this study. The reduction in cell density and chlorophyll a (chl a) concentrations were monitored by reference to non-irradiated samples as controls. Upon irradiation, the cell density and the chl a concentrations became reduced significantly compared to the control (one way ANOVA p <0.001 for the cell density in both the species and p <0.05 for chl a concentrations in both species). A maximum mortality of 0.77 log₁₀ (about 83%) for C. gracilis and 0.68 log₁₀ (about 78%) for S. costatum was observed at 9 ml min^{m 1} flow speed and 0.1 J cm^{m 2} laser fluence. The maximum reduction observed in the chl a concentration was about 26% (control 0.413 and sample 0.306 mg ml^{m 1}) for C. gracilis and 27% (control 0.222 and sample 0.16 mg ml^{m 1}) for S. costatum, when the flow rate was 9 ml min^{m 1} and the fluence 0.1 J cm^{m 2}. In general, mortality increased with an increase in the laser fluence. The results thus show if the cooling water is laser-irradiated to mitigate biofouling, this could result in significant damage to the planktonic flora of the flowing seawater system, which in turn might reduce algal biofilm formation on industrially important structures. The reduction in the chl a concentration showed that the laser irradiations also could result in a significant reduction in the primary productivity of the cooling water.