SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: American films

190

Dopamine has a central role in motivation and reward. Dopaminergic neurons in the ventral tegmental area (VTA) signal the discrepancy between expected and actual rewards (that is, reward prediction error), but how they compute such signals is unknown. We recorded the activity of VTA neurons while mice associated different odour cues with appetitive and aversive outcomes. We found three types of neuron based on responses to odours and outcomes: approximately half of the neurons (type I, 52%) showed phasic excitation after reward-predicting odours and rewards in a manner consistent with reward prediction error coding; the other half of neurons showed persistent activity during the delay between odour and outcome that was modulated positively (type II, 31%) or negatively (type III, 18%) by the value of outcomes. Whereas the activity of type I neurons was sensitive to actual outcomes (that is, when the reward was delivered as expected compared to when it was unexpectedly omitted), the activity of type II and type III neurons was determined predominantly by reward-predicting odours. We ‘tagged’ dopaminergic and GABAergic neurons with the light-sensitive protein channelrhodopsin-2 and identified them based on their responses to optical stimulation while recording. All identified dopaminergic neurons were of type I and all GABAergic neurons were of type II. These results show that VTA GABAergic neurons signal expected reward, a key variable for dopaminergic neurons to calculate reward prediction error.

Concepts: Neuron, Mesolimbic pathway, American films, Game theory, Ventral tegmental area, Reward system, Nervous system, Dopamine

75

Suicides incur in all public transit systems which do not completely impede access to tracks. We conducted two studies to determine if we can reliably identify in stations people at risk of suicide in order to intervene in a timely manner. The first study analysed all CCTV recordings of suicide attempters in Montreal underground stations over 2 years to identify behaviours indicating suicide risk. The second study verified the potential of using those behaviours to discriminate attempters from other passengers in real time.

Concepts: Montreal, American films, Underground city, Suicide, Underground City, Montreal, Rapid transit, Train station, Cultural studies

33

Escaping from predators often demands that animals rapidly negotiate complex environments. The smallest animals attain relatively fast speeds with high frequency leg cycling, wing flapping or body undulations, but absolute speeds are slow compared to larger animals. Instead, small animals benefit from the advantages of enhanced maneuverability in part due to scaling. Here, we report a novel behavior in small, legged runners that may facilitate their escape by disappearance from predators. We video recorded cockroaches and geckos rapidly running up an incline toward a ledge, digitized their motion and created a simple model to generalize the behavior. Both species ran rapidly at 12-15 body lengths-per-second toward the ledge without braking, dove off the ledge, attached their feet by claws like a grappling hook, and used a pendulum-like motion that can exceed one meter-per-second to swing around to an inverted position under the ledge, out of sight. We discovered geckos in Southeast Asia can execute this escape behavior in the field. Quantification of these acrobatic behaviors provides biological inspiration toward the design of small, highly mobile search-and-rescue robots that can assist us during natural and human-made disasters. We report the first steps toward this new capability in a small, hexapedal robot.

Concepts: Escape character, Robot, Behavior, Escape, Ecology, Southeast Asia, American films, English-language films

28

To demonstrate proof-of-principle measurement for physiologic change within an active myofascial trigger point (MTrP) undergoing trigger point release (ischemic compression).

Concepts: Lactic acid, Hematology, Ibn al-Nafis, American films, Protein, Myofascial release, Trigger point

28

Global health initiatives (GHIs) have gained prominence as innovative and effective policy mechanisms to tackle global health priorities. More recent literature reveals governance-related challenges and their unintended health system effects. Much less attention is received by the relationship between these mechanisms, the ideas that underpin them and the country-level practices they generate. The Global Fund has leveraged significant funding and taken a lead in harmonizing disparate efforts to control HIV/AIDS. Its growing influence in recipient countries makes it a useful case to examine this relationship and evaluate the extent to which the dominant public discourse on Global Fund departs from the hidden resistances and conflicts in its operation. Drawing on insights from ethnographic fieldwork and 70 interviews with multiple stakeholders, this article aims to better understand and reveal the public and the hidden transcript of the Global Fund and its activities in India. We argue that while its public transcript abdicates its role in country-level operations, a critical ethnographic examination of the organization and governance of the Fund in India reveals a contrasting scenario. Its organizing principles prompt diverse actors with conflicting agendas to come together in response to the availability of funds. Multiple and discrete projects emerge, each leveraging control and resources and acting as conduits of power. We examine how management of HIV is punctuated with conflicts of power and interests in a competitive environment set off by the Fund protocol and discuss its system-wide effects. The findings also underscore the need for similar ethnographic research on the financing and policy-making architecture of GHIs.

Concepts: Global health, American films, Management, World Health Organization, Funding, Ethnography, Finance, Tuberculosis

27

Recombinase polymerase amplification (RPA) may be used to detect a variety of pathogens, often after minimal sample preparation. However, previous work has shown that whole blood inhibits RPA. In this paper, we show that the concentrations of background DNA found in whole blood prevent the amplification of target DNA by RPA. First, using an HIV-1 RPA assay with known concentrations of non-specific background DNA, we show that RPA tolerates more background DNA when higher HIV-1 target concentrations are present. Then, using three additional assays, we demonstrate that the maximum amount of background DNA that may be tolerated in RPA reactions depends on the DNA sequences used in the assay. We also show that changing the RPA reaction conditions, such as incubation time and primer concentration, has little effect on the ability of RPA to function when high concentrations of background DNA are present. Finally, we develop and characterize a lateral flow-based method for enriching the target DNA concentration relative to the background DNA concentration. This sample processing method enables RPA of 10^4 copies of HIV-1 DNA in a background of 0 to 14 µg background DNA. Without lateral flow sample enrichment, the maximum amount of background DNA tolerated is 2 µg when 10^6 copies of HIV-1 DNA are present. This method requires no heating or other external equipment, may be integrated with upstream DNA extraction and purification processes, is compatible with the components of lysed blood, and has the potential to detect HIV-1 DNA in infant whole blood with high proviral loads.

Concepts: DNA sequencing, Creativity, American films, Molecular biology, Polymerase chain reaction, HIV, DNA

27

The desire to retain personal control over self and life circumstances continues into old age; it exists in tension with late-life vulnerabilities.

Concepts: Retirement, American films, English-language films, Ageing, Management, Old age, Gerontology, Death

27

Abstract A player’s ability to score low is critical to the tournament outcome in golf. The relationships of round scores to fairways hit in regulation or striking distance on two holes per round have been investigated before with some disagreement. The purpose is therefore to examine the relationships of par-4 and par-5 hole scores to tee shot functional accuracy and distance, measured as lie of the ball and penalty, and striking distance or distance to the pin for the second shot. Such information is possible to collect without interviewing players. The best US Professional Golfers' Association Tour players' statistics during a season are used, provided by the Professional Golfers' Association Tour and ShotLink. Distance was measured with laser equipment. The results include significant (P < 0.05) correlations between score and striking distance or distance to pin, when hitting rough but not fairway on par-4s and when hitting fairway and rough on par-5s. It is therefore relevant, for performance, to consider the type of fairway miss as well as the striking distance in relation to the par and length of the hole. The findings can be considered when making gap and needs profiles, and when making tactical decisions for tee shots on different types of holes.

Concepts: PGA Tour, Psychometrics, American films, Professional golf tours, Length, Professional golfer, Professional Golfers Association, Golf

27

A novel enzyme-free and label-free fluorescence aptasensor based on target-catalyzed hairpin self-assembly is developed for amplified detection of adenosine. This aptasensor contains four DNA strands termed as aptamer-catalysis strand, inhibit strand, hairpin structures H1 and H2 which are partially complementary. Meanwhile, a sequence that can form DNA G-quadruplex is partly hidden in the stem of H2. In the absence of adenosine, aptamer-catalysis strand is inhibited, and cannot trigger the self-assembly between H1 and H2. Upon the addition of adenosine, the binding event of aptamer and adenosine triggers the self-assembly between H1 and H2, resulting in the formation of G-quadruplex at the end of H1-H2 complex. The addition of N-methyl mesoporphyrin IX, which has a pronounced structural selectivity for G-quadruplex, generates label-free fluorescence signal. In the optimum conditions, we could detect adenosine as low as 6 μM by monitoring the change in fluorescence intensity. Furthermore, this amplified aptasensor shows high selectivity toward adenosine against its analogs due to the specific recognition ability of the aptamer for the target. Thus, the proposed aptasensor could be used as a simple and selective platform for target detection.

Concepts: Fluorescence spectroscopy, Trigger finger, American films, Trigger, The Target, Signal transduction, Structure, DNA

27

Vascular mineralization has recently emerged as a risk factor for cardiovascular morbidity and mortality. Previously regarded as a passive end-stage process, vascular mineralization is currently recognized as an actively regulated process with cellular and humoral contributions. The discovery that the vitamin K-dependent matrix Gla-protein (MGP) is a strong inhibitor of vascular calcification has propelled our mechanistic understanding of this process and opened novel avenues for diagnosis and treatment. This review focuses on molecular mechanisms of vascular mineralization involving MGP and discusses the potential for treatments and biomarkers to monitor patients at risk for vascular mineralization.

Concepts: Investment, Calcification, Carboxylation, Mortality rate, English-language films, American films