Atmospheric transport is a major pathway of microplastics to remote regions.

In recent years, marine, freshwater and terrestrial pollution with microplastics has been discussed extensively, whereas atmospheric microplastic transport has been largely overlooked. Here, we present global simulations of atmospheric transport of microplastic particles produced by road traffic (TWPs - tire wear particles and BWPs - brake wear particles), a major source that can be quantified relatively well. We find a high transport efficiencies of these particles to remote regions. About 34% of the emitted coarse TWPs and 30% of the emitted coarse BWPs (100 kt yr-1 and 40 kt yr-1 respectively) were deposited in the World Ocean. These amounts are of similar magnitude as the total estimated direct and riverine transport of TWPs and fibres to the ocean (64 kt yr-1). We suggest that the Arctic may be a particularly sensitive receptor region, where the light-absorbing properties of TWPs and BWPs may also cause accelerated warming and melting of the cryosphere.

Source apportionment of circum-Arctic atmospheric black carbon from isotopes and modeling.

Black carbon (BC) contributes to Arctic climate warming, yet source attributions are inaccurate due to lacking observational constraints and uncertainties in emission inventories. Year-round, isotope-constrained observations reveal strong seasonal variations in BC sources with a consistent and synchronous pattern at all Arctic sites. These sources were dominated by emissions from fossil fuel combustion in the winter and by biomass burning in the summer. The annual mean source of BC to the circum-Arctic was 39 ± 10% from biomass burning. Comparison of transport-model predictions with the observations showed good agreement for BC concentrations, with larger discrepancies for (fossil/biomass burning) sources. The accuracy of simulated BC concentration, but not of origin, points to misallocations of emissions in the emission inventories. The consistency in seasonal source contributions of BC throughout the Arctic provides strong justification for targeted emission reductions to limit the impact of BC on climate warming in the Arctic and beyond.

Mitigating ammonia emission from agriculture reduces PM2.5 pollution in the Hai River Basin in China.

The Hai River Basin (HRB), one of the most populated areas in China, is experiencing high NH3 emissions, mostly from agricultural sources, and suffering from strongly enhanced PM2.5 concentrations in all urban areas. Further population growth and urbanization projected until 2030 may exacerbate this situation. Here, the NUFER (NUtrient flows in Food chains, Environment and Resources use) and GAINS (Greenhouse gas - Air pollution Interactions and Synergies) models have been coupled for the first time to understand possible changes of agricultural NH3 emission between 2012 and 2030 and their impacts on ambient PM2.5 concentrations, and to explore options to improve this situation. Results show that agricultural ammonia emissions in the HRB were 1179kt NH3 in 2012, 45% of which was from the hotspots at or near conurbation areas, including Beijing-Tianjin, Tangshan-Qinhuangdao, Shijiazhuang-Baoding, Dezhou, Handan-Liaocheng, and Xinxiang. Without intervention, agricultural ammonia emissions will further increase by 33% by 2030. The impacts of several scenarios were tested with respect to air pollution. Compared to the business-as-usual scenario, a scenario of improved technology and management combined with human diet optimization could greatly reduce emission (by 60%), and lead to 22-43% and 9-24% decrease of the secondary inorganic aerosols and PM2.5 concentrations, respectively, in the hotspots of NH3 emissions. Our results further confirmed that ammonia control is needed for air pollution abatement strategies (SO2, NOx and primary PM reduction) to be effective in terms of PM2.5.

Effect of dietary fat on the pharmacokinetics and pharmacodynamics of cyclosporine in kidney transplant recipients.

OBJECTIVE: To investigate the effect of dietary fat on the pharmacokinetics and pharmacodynamics of cyclosporine. METHODS: Sixteen stable kidney transplants recipients (mean age, 50.4 years; age range, 19 to 63 years; six women) who were maintained on oral cyclosporine therapy were randomized to receive a high- or low-fat diet for periods of 7 days in a balanced crossover study. The crossover was separated by a 7-day washout period, when the usual diet was followed. Oral cyclosporine was taken once daily with breakfast. Twenty-four-hour pharmacokinetic studies were conducted during each dietary period on day 6 after oral cyclosporine and on day 7 after a 3-hour intravenous cyclosporine infusion (30% of oral dose). Sequential blood samples were also taken after the oral dose on day 6 for lymphocyte transformation studies. RESULTS: The mean breakfast fat intake and total daily fat intake were 6.5 and 5.5 times higher, respectively, during the high-fat diet than during the low-fat diet. The bioavailability and clearance of cyclosporine were found to be significantly higher during the high-fat diet (p = 0.02 and p = 0.01, respectively). As a consequence, the area under the blood concentration-time curve (AUC) after the oral dose was not significantly different between the two diets. There were no significant differences in concanavalin A-stimulated proliferation of peripheral blood lymphocytes between the high- and low-fat diets. CONCLUSIONS: An increased fat content of food significantly increases cyclosporine bioavailability and clearance. However, this is unlikely to be of clinical importance during oral administration because the AUC and pharmacodynamics of cyclosporine are not affected significantly.

Prospective evaluation of antiemetic outcome following high-dose chemotherapy with hematopoietic stem cell support.

Considerable progress has been made in improving the control of chemotherapy-induced emesis. The impact of available antiemetic options for patients receiving stem cell transplants is unclear, as few prospective data have been collected. We prospectively evaluated antiemetic outcome in patients receiving stem cell transplantation over a 7-day period following the initiation of chemotherapy. The primary endpoints were the number of emetic episodes and the extent of nausea measured on a four-point scale. Eighty-two patients were evaluated. Ninety-five percent of patients had nausea during the first week of treatment; 80% had at least one emetic episode. The percentage of patients with emesis was as follows: day 1: 13%, day 2: 21%, day 3: 30%, day 4: 38%, day 5: 44%, day 6: 39%, day 7: 18%. In multivariate analysis, gender, emesis with prior chemotherapy, history of morning or motion sickness, type of transplant (auto vs allo), use of total body irradiation, or use of dexamethasone did not effect emesis control. Most patients receiving high-dose chemotherapy experience incompletely controlled emesis. Control of nausea and emesis progressively worsened with each subsequent day following initiation of chemotherapy, reaching a nadir on day 5. New treatment approaches are needed to improve emesis control in this patient population.

Stem cell engraftment strategies.

The donor stem cell phenotype and host microenvironment determine the outcome of a stem cell transplant. In a series of transplant studies in syngeneic male to female or congenic Ly5.1/Ly5.2 models in which hosts have received no or minimal irradiation (100 cGy), evidence overwhelmingly supports the concept that syngeneic engraftment is determined by stem cell competition. These approaches can be extended to H-2 mismatched allogeneic mouse combination when antigen pre-exposure and CD40-CD40 ligand antibody blockage are employed. A human trial in patients with resistant neoplasia infusing pheresed blood with 10(8) CD3 cells/kg showed that tumor responses and complete chimerism occur with very low levels of CD34+ cells/kg and that the extent of previous treatment is a critical factor in determining chimerism. A major feature of transplants is the phenotype of the donor stem cell. This phenotype shows dramatic reversible plasticity involving differentiation, adhesion protein expression, and engraftment with cytokine-induced cell-cycle transit. Homing is probably also plastic. Marked fluctuations in engraftment capacity are also seen at different points in marrow circadian rhythm.

Pharmacological mechanisms and animal models of cognition.

Requirements for an effective animal model of cognition are discussed with special reference to the cholinergic hypothesis of Alzheimer's disease. It is argued, with reference to research on vasopressin and ACE inhibitors, that many putative animal models of cognition lack predictive clinical validity because they either confound the effects of cognitive and arousal processes, or fail to model a specific component of cognitive functioning. A survey of recent research on the cholinergic hypothesis illustrates how these weaknesses can be overcome. Studies involving scopolamine and basal forebrain excitatory amino acid lesion models of the cholinergic deficit in Alzheimer's disease have employed a delayed-matching-to-position test in rodents which, unlike passive avoidance, allows the effects of memory and attentional variables to be distinguished. In combination with recent human studies, these experiments suggest that the cholinergic system has a major role in executive control of attentional resources, and lead to the recommendation of a 'top down' strategy in the investigation of neurochemical processes and pharmacological mechanisms underlying cognition.

Social blockade of taste-aversion learning in Norway rats (Rattus norvegicus): is it a social phenomenon?

In Experiment 1, hooded rats (Rattus norvegicus) were exposed to a novel diet in a food dish or on a conspecific; they were allowed to consume the same diet and then were injected with a toxin LiCl. Later both groups ate more of the novel diet than animals that had not been exposed, and the conspecific-exposed group ate more than the dish-exposed group. Reducing aversion learning by exposure on a conspecific is known as social blockade. We examined if this effect is because a conspecific intensifies dietary cues and thereby increases latent inhibition. Experiment 2 failed to show that diet on a conspecific is a more effective conditioned stimulus for taste-aversion learning than diet in a dish, and Experiment 3 showed that diet in a dish is an effective overshadowing stimulus in aversion learning but diet on a conspecific is not. These results suggest that social blockade cannot readily be assimilated to a latent-inhibition model and may be a distinctly social form of learning.

Estimating long-term population exposure to ozone in urban areas of Europe.

Tropospheric ozone concentrations regarded as harmful for human health are frequently encountered in Central Europe in summertime. Although ozone formation generally results from precursors transported over long distances, in urban areas local effects, such as reactions due to nearby emission sources, play a major role in determining ozone concentrations. Europe-wide mapping and modeling of population exposure to high ozone concentrations is subject to many uncertainties, because small-scale phenomena in urban areas can significantly change ozone levels from those of the surroundings. Currently the integrated assessment modeling of European ozone control strategies is done utilizing the results of large-scale models intended for estimating the rural background ozone levels. This paper presents an initial study on how much local nitrogen oxide (NOx) concentrations can explain variations between large-scale ozone model results and urban ozone measurements, on one hand, and between urban and nearby rural measurements, on the other. The impact of urban NOx concentrations on ozone levels was derived from chemical equations describing the ozone balance. The study investigated the applicability of the method for improving the accuracy of modeled population exposure, which is needed for efficient control strategy development. The method was tested with NOx and ozone measurements from both urban and rural areas in Switzerland and with the ozone predictions of the large-scale photochemical model currently used in designing Europe-wide control strategies for ground-level ozone. The results suggest that urban NOx levels are a significant explanatory factor in differences between urban and nearby rural ozone concentrations and that the phenomenon could be satisfactorily represented with this kind of method. Further research efforts should comprise testing of the method in more locations and analyzing the performance of more widely applicable ways of deriving the initial parameters.

Imitation in rats (Rattus norvegicus): The role of demonstrator action.

In a bidirectional control procedure, rats had their first opportunity to push a joystick immediately after observing, from an adjacent compartment, the joystick moving 50 times either to the right or to the left, with each movement signalling the delivery of inaccessible food. Half of these animals observed the joystick moving automatically, and half observed a conspecific demonstrator pushing the joystick. When they were given direct access to the joystick, the observers were rewarded for both left and right pushes. Rats that had observed the joystick moving through the action of a conspecific demonstrator showed a response bias in favour of the observed direction of joystick movement (Experiment 1), while rats that had observed the joystick moving automatically, either in the presence or absence of a passive conspecific, did not show observation-consistent responding (Experiments 1 and 2). These results apparently confirm that rats are capable of imitation or observational learning.

Theory of mind and other domain-specific hypotheses.

The commentators do not contest the target article's claim that there is no compelling evidence of theory of mind in primates, and recent empirical studies further support this view. If primates lack theory of mind, they may still have other behavior control mechanisms that are adaptive in complex social environments. The Somatic Marker Mechanism (SMM) is a candidate, but the SMM hypothesis postulates a much weaker effect of natural selection on social cognition than the theory of mind hypothesis (on inputs to cognitive mechanisms, not on the mechanisms themselves), and there is currently no evidence that it is specific to social stimuli or to primates. "Two Guesser" training would make the goggles test too chauvinistic, and in its current form the goggles problem could not be solved by physical matching because, while wearing goggles, an individual cannot see itself seeing.

Cell mediated immunity after measles in Guinea-Bissau: historical cohort study.

OBJECTIVE: To investigate whether children who have had measles have reduced general cell mediated immunity three years later compared with vaccinated children who have not had measles. DESIGN: Historical cohort study. SETTING: Bissau, Guinea-Bissau. SUBJECTS: 391 children aged 3-13 years who were living in Bissau during a measles epidemic in 1991 and still lived there. These included 131 primary cases and 139 secondary cases from the epidemic and 121 vaccinated controls with no history of measles. MAIN OUTCOME MEASURES: General cell mediated immunity assessed by measurement of delayed type hypersensitivity skin responses to seven recall antigens. Anergy was defined as a lack of response to all antigens. RESULTS: 82 out of 268 cases of measles (31%) were anergic compared with 20 of the 121 vaccinated controls (17%) (odds ratio adjusted for potential confounding variables 2.2 (95% confidence interval 1.2 to 4.0); P 0.009). The prevalence of anergy was higher in secondary cases (33% (46/138)) than in primary cases (28% (36/130)), although this difference was not significant. Anergy was more common in the rainy season (unadjusted prevalence 31% (91/291) than in the dry season (11% (11/98)) (adjusted odds ratio 4.8 (2.2 to 10.3)). This seasonal increase occurred predominantly in the case of measles. CONCLUSION: Reduced general cell mediated immunity may contribute to the higher long term mortality in children who have had measles compared with recipients of standard measles vaccine and to the higher child mortality in the rainy season in west Africa.

An integrated instrumental setup for the combination of atomic force microscopy with optical spectroscopy.

In recent years, the study of single biomolecules using fluorescence microscopy and atomic force microscopy (AFM) techniques has resulted in a plethora of new information regarding the physics underlying these complex biological systems. It is especially advantageous to be able to measure the optical, topographical, and mechanical properties of single molecules simultaneously. Here an AFM is used that is especially designed for integration with an inverted optical microscope and that has a near-infrared light source (850 nm) to eliminate interference between the optical experiment and the AFM operation. The Tip Assisted Optics (TAO) system consists of an additional 100 x 100-microm(2) X-Y scanner for the sample, which can be independently and simultaneously used with the AFM scanner. This allows the offset to be removed between the confocal optical image obtained with the sample scanner and the simultaneously acquired AFM topography image. The tip can be positioned exactly into the optical focus while the user can still navigate within the AFM image for imaging or manipulation of the sample. Thus the tip-enhancement effect can be maximized and it becomes possible to perform single molecule manipulation experiments within the focus of a confocal optical image. Here this is applied to simultaneous measurement of single quantum dot fluorescence and topography with high spatial resolution.

Causes and consequences of imitation.

Recent behavioural and neuroscientific research concerning imitation has revealed evidence of experience-dependent imitation in chimpanzees and birds, wide ranging imitation deficits in autism, and unintentional imitation in adult humans. This review examines these findings and also evaluates evidence of neonatal imitation and intentional imitation in infancy, and evidence suggesting that the left inferior frontal gyrus is specialized for imitation. At the theoretical level, the empirical findings support the view that the perceptual-motor translation that is a unique and defining property of imitation depends primarily on direct links between sensory and motor representations established through correlated experience of observing movements and carrying them out.

Theory of mind in nonhuman primates.

Since the BBS article in which Premack and Woodruff (1978) asked "Does the chimpanzee have a theory of mind?," it has been repeatedly claimed that there is observational and experimental evidence that apes have mental state concepts, such as "want" and "know." Unlike research on the development of theory of mind in childhood, however, no substantial progress has been made through this work with nonhuman primates. A survey of empirical studies of imitation, self-recognition, social relationships, deception, role-taking, and perspective-taking suggests that in every case where nonhuman primate behavior has been interpreted as a sign of theory of mind, it could instead have occurred by chance or as a product of nonmentalistic processes such as associative learning or inferences based on nonmental categories. Arguments to the effect that, in spite of this, the theory of mind hypothesis should be accepted because it is more parsimonious than alternatives or because it is supported by convergent evidence are not compelling. Such arguments are based on unsupportable assumptions about the role of parsimony in science and either ignore the requirement that convergent evidence proceed from independent assumptions, or fail to show that it supports the theory of mind hypothesis over nonmentalist alternatives. Progress in research on theory of mind requires experimental procedures that can distinguish the theory of mind hypothesis from nonmentalist alternatives. A procedure that may have this potential is proposed. It uses conditional discrimination training and transfer tests to determine whether chimpanzees have the concept "see." Commentators are invited to identify flaws in the procedure and to suggest alternatives.

Social learning in animals: categories and mechanisms.

There has been relatively little research on the psychological mechanisms of social learning. This may be due, in part, to the practice of distinguishing categories of social learning in relation to ill-defined mechanisms (Davis, 1973; Galef, 1988). This practice both makes it difficult to identify empirically examples of different types of social learning, and gives the false impression that the mechanisms responsible for social learning are clearly understood. It has been proposed that social learning phenomena be subsumed within the categorization scheme currently used by investigators of asocial learning. This scheme distinguishes categories of learning according to observable conditions, namely, the type of experience that gives rise to a change in an animal (single stimulus vs. stimulus-stimulus relationship vs. response-reinforcer relationship), and the type of behaviour in which this change is detected (response evocation vs. learnability) (Rescorla, 1988). Specifically, three alignments have been proposed: (i) stimulus enhancement with single stimulus learning, (ii) observational conditioning with stimulus-stimulus learning, or Pavlovian conditioning, and (iii) observational learning with response-reinforcer learning, or instrumental conditioning. If, as the proposed alignments suggest, the conditions of social and asocial learning are the same, there is some reason to believe that the mechanisms underlying the two sets of phenomena are also the same. This is so if one makes the relatively uncontroversial assumption that phenomena which occur under similar conditions tend to be controlled by similar mechanisms. However, the proposed alignments are intended to be a set of hypotheses, rather than conclusions, about the mechanisms of social learning; as a basis for further research in which animal learning theory is applied to social learning. A concerted attempt to apply animal learning theory to social learning, to find out whether the same mechanisms are responsible for social and asocial learning, could lead both to refinements of the general theory, and to a better understanding of the mechanisms of social learning. There are precedents for these positive developments in research applying animal learning theory to food aversion learning (e.g. Domjan, 1983; Rozin & Schull, 1988) and imprinting (e.g. Bolhuis, de Vox & Kruit, 1990; Hollis, ten Cate & Bateson, 1991). Like social learning, these phenomena almost certainly play distinctive roles in the antogeny of adaptive behaviour, and they are customarily regarded as 'special kinds' of learning (Shettleworth, 1993).(ABSTRACT TRUNCATED AT 400 WORDS)

Do rats in a two-action test encode movement egocentrically or allocentrically?

Two-action tests of imitation compare groups that observe topographically different responses to a common manipulandum. The general aim of the two experiments reported here was to find a demonstrator-consistent responding effect in a procedure that could be elaborated to investigate aspects of what was learned about the demonstrated lever response. Experiment 1 was a pilot study with rats of a variant of the two-action method of investigating social learning about observed responses. Groups of observer rats ( Rattus norvegicus) saw a demonstrator push a lever up or down for a food reward. When these observers were subsequently given access to the lever and rewarded for responses in both directions, their directional preferences were compared with two 'screen control' groups that were unable to see their demonstrators' behaviour. Demonstrator-consistent responding was found to be restricted to observers that were able to see demonstrator performance, suggesting that scent cues alone were insufficient to cue a preference for the demonstrators' response direction and thereby that the rats learned by observation about body movements (imitation) or lever movement (emulation). Experiment 2 assessed responding on two levers, one that had been manipulated by the demonstrator, and a second, transposed lever positioned some distance away. Demonstrator-consistent responding was abolished when actions were observed and performed in different parts of the apparatus, suggesting that observed movement was encoded allocentrically with respect to the apparatus rather than egocentrically with respect to the actor's body. With particular reference to the influence of scent cues, the results are discussed in relation to the strengths and weaknesses of this and other varieties of the two-action procedure as tests of imitation in animals and human infants.

Motor learning by observation: evidence from a serial reaction time task.

This study sought evidence of observational motor learning, a type of learning in which observation of the skilled performance of another person not only facilitates motor skill acquisition but does so by contributing to the formation of effector-specific motor representations. Previous research has indicated that observation of skilled performance engages cognitive processes similar to those occurring during action execution or physical practice, but has not demonstrated that these include processes involved in effector-specific representation. In two experiments, observer subjects watched the experimenter performing a serial reaction time (SRT) task with a six-item unique sequence before sequence knowledge was assessed by response time and/or free generation measures. The results suggest that: (1) subjects can acquire sequence information by watching another person performing the task (Experiments 1-2); (2) observation results in as much sequence learning as task practice when learning is measured by reaction times (RTs) and more than task practice when sequence learning is measured by free generation performance (Experiment 2, Part 1); and (3) sequence knowledge acquired by model observation can be encoded motorically--that is, in an effector-specific fashion (Experiment 2, Part 2).