843 research outputs found

    Reactive control and reasoning assistance for scientific laboratory instruments

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    Scientific laboratory instruments that are involved in chemical or physical sample identification frequently require substantial human preparation, attention, and interactive control during their operation. Successful real-time analysis of incoming data that supports such interactive control requires: (1) a clear recognition of variance of the data from expected results; and (2) rapid diagnosis of possible alternative hypotheses which might explain the variance. Such analysis then aids in decisions about modifying the experiment protocol, as well as being a goal itself. This paper reports on a collaborative project at the NASA Ames Research Center between artificial intelligence researchers and planetary microbial ecologists. Our team is currently engaged in developing software that autonomously controls science laboratory instruments and that provides data analysis of the real-time data in support of dynamic refinement of the experiment control. the first two instruments to which this technology has been applied are a differential thermal analyzer (DTA) and a gas chromatograph (GC). coupled together, they form a new geochemicstry and microbial analysis tool that is capable of rapid identification of the organiz and mineralogical constituents in soils. The thermal decomposition of the minerals and organics, and the attendance release of evolved gases, provides data about the structural and molecular chemistry of the soil samples

    Teaching Research Methodologies to Professionally Oriented Honors Students

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    The benefits of encouraging undergraduate students to pursue independent research have been well documented (Craney; Guterman; Hathaway et al.; Ishiyama; Kremer and Bringle; Volkwein and Carbone). Introducing students to research processes and protocols is always a challenge, particularly for students enrolled in professionally oriented, discipline-specific colleges: so called “specialty schools.” In these colleges, preparing students to do high-level research is complicated by the nature and priorities of the students as well as by the particularities of the curriculum, which is invariably more restricted in scope than that of a conventional liberal arts college. Undergraduate specialty school students tend to be highly focused on preparing for their careers, and few plan to go on to research-oriented graduate programs. Nevertheless, specialty schools typically include many liberal arts requirements in their curricula in order to give students a well-rounded undergraduate education

    Examination of optimizing information flow in networks

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    The central role of the Internet and the World-Wide-Web in global communications has refocused much attention on problems involving optimizing information flow through networks. The most basic formulation of the question is called the "max flow" optimization problem: given a set of channels with prescribed capacities that connect a set of nodes in a network, how should the materials or information be distributed among the various routes to maximize the total flow rate from the source to the destination. Theory in linear programming has been well developed to solve the classic max flow problem. Modern contexts have demanded the examination of more complicated variations of the max flow problem to take new factors or constraints into consideration; these changes lead to more difficult problems where linear programming is insufficient. In the workshop we examined models for information flow on networks that considered trade-offs between the overall network utility (or flow rate) and path diversity to ensure balanced usage of all parts of the network (and to ensure stability and robustness against local disruptions in parts of the network). While the linear programming solution of the basic max flow problem cannot handle the current problem, the approaches primal/dual formulation for describing the constrained optimization problem can be applied to the current generation of problems, called network utility maximization (NUM) problems. In particular, primal/dual formulations have been used extensively in studies of such networks. A key feature of the traffic-routing model we are considering is its formulation as an economic system, governed by principles of supply and demand. Considering channel capacities as a commodity of limited supply, we might suspect that a system that regulates traffic via a pricing scheme would assign prices to channels in a manner inversely proportional to their respective capacities. Once an appropriate network optimization problem has been formulated, it remains to solve the optimization problem; this will need to be done numerically, but the process can greatly benefit from simplifications and reductions that follow from analysis of the problem. Ideally the form of the numerical solution scheme can give insight on the design of a distributed algorithm for a Transmission Control Protocol (TCP) that can be directly implemented on the network. At the workshop we considered the optimization problems for two small prototype network topologies: the two-link network and the diamond network. These examples are small enough to be tractable during the workshop, but retain some of the key features relevant to larger networks (competing routes with different capacities from the source to the destination, and routes with overlapping channels, respectively). We have studied a gradient descent method for solving obtaining the optimal solution via the dual problem. The numerical method was implemented in MATLAB and further analysis of the dual problem and properties of the gradient method were carried out. Another thrust of the group's work was in direct simulations of information flow in these small networks via Monte Carlo simulations as a means of directly testing the efficiencies of various allocation strategies

    Microorganisms of food ice cubes and their transfer to drinks

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    The present work was carried out to investigate the microbiological characteristics of the ice cubes produced at different levels: 1) home-made (HM) from domestic freezers; 2) produced by ice machines in bars and pubs (BP); 3) produced by ice industries (IN). BP samples were collected from the box stocks. HM and BP samples were transferred into sterile stomacher bags. IN samples were provided in the manufacturers\u2019 plastic bags. Samples were transported into thermal insulated boxes. Five samples per each production level, forming a total of 15 samples (HM1-HM5, BP1-BP5, IN1-IN5), were collected in duplicate in two consecutive months. Each ice sample was thawed in 1 L sterile Dhuram\u2019s bottle at room temperature and subjected to the membrane filtration analyses. Total mesophilic microorganisms (TMM), total psychrotrophic microorganisms (TPM), pseudomonads, members of the Enterobacteriaceae family, coliforms, enterococci, yeasts and moulds were investigated. When the amounts of colonies were uncountable, 1 mL of sample was directly inoculated into agar media. All results were expressed as colony forming units (CFU)/100 mL of thawed ice. TMM were in the range 100-9600, 312-6300 and 130-4000 for HM, BP and IN samples, respectively. Three HM and two IN samples were negative for the presence of TPM. The highest concentration (960) was found for IN2. Pseudomonads were detected in all HM samples but the highest levels were registered for BP1 (390) and IN2 (384). Except IN4, Enterobacteriaceae were found in all samples. All INs and 4 HM samples did not displayed coliforms. By contrast, they were hosted in all BP samples, ranging from 1 to 184. Enterococci were never found in HM samples, but detected in two INs and 3 BPs. Except IN1, moulds were always registered, while yeasts developed from the majority of HM and IN samples and two BP samples. The colonies representative for the different morphologies were randomly picked up from plates, purified to homogeneity and subjected to a phenotypic grouping. Yeasts and bacteria were subjected to the genetic identification by sequencing of D1/D2 domains of 26S rRNA gene and partial sequencing of 16S rRNA gene, respectively, while moulds were identified phenotypically. So far, the species mostly represented among bacteria, as evaluated only by the forward 16S rRNA gene sequence, were Bacillus spp., Pseudomonas spp., Pantoea spp., Pantoea agglomerans, Enterococcus faecium, and Agrobacterium tumefaciens. Candida intermedia and Pichia guillermondii were identified among yeasts and Penicillium spp. among moulds. The work was also aimed to monitor the microbial transfer from ice to humans through drinks. To this purpose, each microorganism was inoculated singly in sterile mineral water to produce contaminated ice cubes using disposable ice cube trays. Inoculums occurred at the highest concentrations found in the ice cubes analysed. The concentrations of the microorganisms were followed in six different types of drinks, including alcoholic (vodka and whiskey), moderate alcoholic (Martini), sparkling (tonic water), sugary (peach tea) and sugary sparkling (coke) drinks. In order to simulate the contamination of drinks by ice during consumption, six ice cubes (corresponding to 60 mL) containing each microorganism were added to 100 mL of each drink (simulating a bar administration) in sterile cups and, after 1 h, the entire volume was analysed by membrane filtration. A physiological solution was used as control. So far, the tests were performed with Penicillium spp. and P. agglomerans. Penicillium was not influenced by the different drinks, since, after 1 h, its level did not change. Regarding P. agglomerans, which is an opportunistic pathogen causing urinary tract infections, its concentration in peach tea was superimposable to that found in physiological solution, while it decreased in all other drinks. In particular, the concentration of this bacterium almost halved in vodka, coke and tonic water, diminished consistently in Martini and completely disappeared in whiskey. Experimentations are in progress to determine the behaviour of the other microorganisms in these systems. These data evidenced that the worst hygienic characteristics were found in BP samples, while the majority of ice cubes produced in specialized industries were characterized by acceptable microbiological parameters. This work indicated that the concentration of P. agglomerans is reduced by alcohol and CO2, but further in vivo assays are necessary to better clarify their role on the other ice microorganisms

    Design and Testing of Autonomous Distributed Space Systems

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    Distributed Space Systems (DSS) are an emerging class of mission designs that enable new scientific and commercial opportunities. In order to enable those new opportunities, these systems will need to have significantly expanded autonomous capabilities compared to their single-spacecraft predecessors. In this paper, we present Distributed Spacecraft Autonomy (DSA) project, a payload on NASA’s Starling spacecraft experiment. We first describe a step-by-step process for characterizing what features are needed in an autonomous DSS, and show how this process applied to DSA. We then describe the Starling mission, a four-spacecraft swarm hosting multiple DSS payloads. We then describe DSA, which will mature in-space networking and autonomous planning technologies to measure topside ionosophere features using data from the Starling spacecraft’s GPS receivers. We describe how DSA will coordinate observations of GPS satellites using Starling’s underlying communications infrastructure combined with novel DSS technology. The flight validation of DSS technology will provide mature technology to enable future DSS missions

    Investigating the timecourse of accessing conversational implicatures during incremental sentence interpretation

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    Many contextual inferences in utterance interpretation are explained as following from the nature of conversation and the assumption that participants are rational. Recent psycholinguistic research has focussed on certain of these ‘Gricean’ inferences and have revealed that comprehenders can access them in online interpretation. However there have been mixed results as to the time-course of access. Some results show that Gricean inferences can be accessed very rapidly, as rapidly as any other contextually specified information (Sedivy, 2003; Grodner, Klein, Carbery, & Tanenhaus, 2010); while other studies looking at the same kind of inference suggest that access to Gricean inferences are delayed relative to other aspects of semantic interpretation (Huang & Snedeker, 2009; in press). While previous timecourse research has focussed on Gricean inferences that support the online assignment of reference to definite expressions, the study reported here examines the timecourse of access to scalar implicatures, which enrich the meaning of an utterance beyond the semantic interpretation. Even if access to Gricean inference in support of reference assignment may be rapid, it is still unknown whether genuinely enriching scalar implicatures are delayed. Our results indicate that scalar implicatures are accessed as rapidly as other contextual inferences. The implications of our results are discussed in reference to the architecture of language comprehension

    A mind you can count on: validating breath counting as a behavioral measure of mindfulness.

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    Mindfulness practice of present moment awareness promises many benefits, but has eluded rigorous behavioral measurement. To date, research has relied on self-reported mindfulness or heterogeneous mindfulness trainings to infer skillful mindfulness practice and its effects. In four independent studies with over 400 total participants, we present the first construct validation of a behavioral measure of mindfulness, breath counting. We found it was reliable, correlated with self-reported mindfulness, differentiated long-term meditators from age-matched controls, and was distinct from sustained attention and working memory measures. In addition, we employed breath counting to test the nomological network of mindfulness. As theorized, we found skill in breath counting associated with more meta-awareness, less mind wandering, better mood, and greater non-attachment (i.e., less attentional capture by distractors formerly paired with reward). We also found in a randomized online training study that 4 weeks of breath counting training improved mindfulness and decreased mind wandering relative to working memory training and no training controls. Together, these findings provide the first evidence for breath counting as a behavioral measure of mindfulness

    Resuscitating the Physician-Patient Relationship: Emergency Department Communication in an Academic Medical Center

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    Study objective: We characterize communication in an urban, academic medical center emergency department (ED) with regard to the timing and nature of the medical history survey and physical examination and discharge instructions. Methods: Audiotaping and coding of 93 ED encounters (62 medical history surveys and physical examinations, 31 discharges) with a convenience sample of 24 emergency medicine residents, 8 nurses, and 93 nonemergency adult patients. Results: Patients were 68% women and 84% black, with a mean age of 45 years. Emergency medicine providers were 70% men and 80% white. Of 62 medical history surveys and physical examinations, time spent on the introduction and medical history survey and physical examination averaged 7 minutes 31 seconds (range 1 to 20 minutes). Emergency medicine residents introduced themselves in only two thirds of encounters, rarely (8%) indicating their training status. Despite physician tendency (63%) to start with an open-ended question, only 20% of patients completed their presenting complaint without interruption. Average time to interruption (usually a closed question) was 12 seconds. Discharge instructions averaged 76 seconds (range 7 to 202 seconds). Information on diagnosis, expected course of illness, self-care, use of medications, time-specified follow-up, and symptoms that should prompt return to the ED were each discussed less than 65% of the time. Only 16% of patients were asked whether they had questions, and there were no instances in which the provider confirmed patient understanding of the information. Conclusion: Academic EDs present unique challenges to effective communication. In our study, the physician-patient encounter was brief and lacking in important health information. Provision of patient-centered care in academic EDs will require more provider education and significant system support

    Cohort profile : the Australian genetics of depression study

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    Purpose Depression is the most common psychiatric disorder and the largest contributor to global disability. The Australian Genetics of Depression study was established to recruit a large cohort of individuals who have been diagnosed with depression at some point in their lifetime. The purpose of establishing this cohort is to investigate genetic and environmental risk factors for depression and response to commonly prescribed antidepressants. Participants A total of 20 689 participants were recruited through the Australian Department of Human Services and a media campaign, 75% of whom were female. The average age of participants was 43 years±15 years. Participants completed an online questionnaire that consisted of a compulsory module that assessed self-reported psychiatric history, clinical depression using the Composite Interview Diagnostic Interview Short Form and experiences of using commonly prescribed antidepressants. Further voluntary modules assessed a wide range of traits of relevance to psychopathology. Participants who reported they were willing to provide a DNA sample (75%) were sent a saliva kit in the mail. Findings to date 95% of participants reported being given a diagnosis of depression by a medical practitioner and 88% met the criteria for a lifetime depressive episode. 68% of the sample report having been diagnosed with another psychiatric disorder in addition to depression. In line with findings from clinical trials, only 33% of the sample report responding well to the first antidepressant they were prescribed. Future plans A number of analyses to investigate the genetic architecture of depression and common comorbidities will be conducted. The cohort will contribute to the global effort to identify genetic variants that increase risk to depression. Furthermore, a thorough investigation of genetic and psychosocial predictors of antidepressant response and side effects is planned. © © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ
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