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This study reports on the preparation of eight new boron-containing capsaicinoids bearing long aliphatic chains, as an expansion of our previous studies to include tertiary amide derivatives into our substrate scope. Our boron-moiety, a pinacolboronate ester (Bpin) fragment, has been incorporated in two locations: as an aryl substituent of the capsaicinoid produced by the reductive amination of veratraldehyde, or at the terminal end of an aliphatic substituent using an iridium catalyzed hydroboration reaction. We report that most compounds in our series show moderate antimicrobial and cytotoxic activity, surpassing activities noted in our previous study.

Anania hortulata (Linnaeus, 1758) (Lepidoptera: Crambidae: Pyraustinae) is a strikingly coloured, common, and widespread species that has long been recognised as a single species widely distributed in Asia, Europe, and North America. Using a combination of molecular and morphometric data, this study resolved that A. hortulata is actually a species complex of two superficially indistinguishable species. Phylogenetic and network analyses based on the mitochondrial COI gene discriminated lineages from all major geographical regions of China as distinct, A. sinensis Yang and Landry new species, whereas A. hortulata occurs in Central Asia, Europe, and North America. Nuclear gene (CAD) and morphological differences in the genital characters provided further evidence for the separation of A. hortulata and A. sinensis.

Computer-assisted personal interviewing (CAPI) has increasingly been used in developing countries, but literature and training on best practices have not kept pace. Drawing on our experiences using CAPI to implement the Local Governance Performance Index (LGPI) in Tunisia and Malawi and an election study in Jordan, this paper makes practical recommendations for mitigating challenges and leveraging CAPI’s benefits to obtain high quality data. CAPI offers several advantages. Tablets facilitate complex skip patterns and randomization of long question batteries and survey experiments, which helps to reduce measurement error. Tablets’ global positioning system (GPS) technology reduces sampling error by locating sampling units and facilitating analysis of neighborhood effects. Immediate data uploading, time-stamps for individual questions, and interview duration capture allowed real time data quality checks and interviewer monitoring. Yet, CAPI entails challenges, including costs of learning new software; questionnaire programming; and piloting to resolve coding bugs; and ethical and logistical considerations, such as electricity and Internet connectivity.

Why do authoritarian regimes try to improve the quality of their governance? In the absence of democratic institutions to monitor, reward and punish their performance, authoritarian politicians are normally expected to seek their self-interest through corruption and rewards to cronies, rather than providing for the public welfare. However, the Chinese state has actively promoted improved governance in recent years, with greater attention to quality of life issues to balance the primary focus on sustaining rapid economic growth. This paper analyses intra-national variation in the provision of public goods in urban China and the impact of public goods on regime support. Does better governance lead to higher levels of public support for the regime, even in the absence of democratic elections? Our evidence suggests that it does, with a greater impact for the local level than for the centre.

Preferred temperature (Tpref) has been measured in over 100 species of aquatic and 300 species of terrestrial ectotherms as a metric for assessing behavioural thermoregulation in variable environments and, as such, has been linked to ecological processes ranging from individual behaviour to population and community dynamics. Due to the asymmetric shape of performance curves, Tpref is typically lower than the optimal temperature (Topt, where physiological performance is at its peak), and the degree of this mismatch increases with variability in Tb. Intertidal ectotherms experience huge variability in Tb on a daily basis and therefore provide a good system to test whether the relationship between Tpref and variation in Tb holds in more extreme environments. A review of the literature, however, only revealed comparisons between Tpref and Topt for five intertidal species and measurements of Tpref for 23 species. An analysis of this limited literature for intertidal ectotherms showed a positive relationship between acclimation temperature and Tpref. There was, however, great variation in the methodologies employed to make these assessments. Factors contributing to behavioural thermoregulation in intertidal ectotherms including small body size; low mobility; interactions among individuals; endogenous clocks; metabolic effects; thermal sensitivity; sampling of the thermal environment and recent acclimation history were considered to varying degrees when measuring Tpref, confounding comparisons between species. The methodologies used to measure Tpref in intertidal ectotherms were reviewed in light of each of these factors, and methodologies proposed to standardize approaches. Given the theoretical predictions about the relationships between Tpref and variability in Tb, the spatial and temporal thermal variability experienced by intertidal ectotherms provides numerous opportunities to test these expectations if assessed in a standardized manner, and can potentially provide insights into the value of behavioural thermoregulation in the more thermally variable environments predicted to occur in the near future.

Shellfish ( Crassostrea virginica and Mercenaria mercenaria ) and shellfish-raising waters from a variety of Long Island and New Jersey marine embayments were examined for the presence of human enteroviruses. Little difference in virological quality was noted between areas designated as being open or closed to shellfishing. Viral isolations could not be correlated with coliform counts from identical samples, indicating the need to re-evaluate the use of bacterial standards as indices of the overall sanitary quality of water and shellfish.

Methods for recovery of poliovirus type 1 (LSc2ab) from naturally-infected oysters ( Crassostrea gigas ) were examined. Extraction procedures analyzed included glycine-saline and polyelectrolyte (Cat-Floc) methods followed by concentration using modifications of an acid precipitation technique, Direct viral assay of shellfish homogenates, when compared to virus recovery following extraction, indicated that substantially fewer viruses were detected in initial homogenates. These data appeared to support the contention that input values based on homogenate assay were inappropriate in determining recovery efficiencies with naturally-infected shellfish. Since absolute efficiencies could not be determined, relative efficiencies using samples from pooled homogenates were used to determine the recovery efficiencies of various extraction procedures. Cat-Floc extraction followed by a beef extract-modified acid precipitation technique resulted in higher virus recoveries than a glycine-saline extraction procedure.

Along with the rapid urbanization in China, the state of mental health also receives growing attention. Empirical measures, however, have not been developed to assess the impact of urbanization on mental health and the dramatic spatial variations. Innovatively linking the 2010 Chinese Population Census with a 2011 national survey of urban residents, we first assess the impact of urbanization on depressive symptoms measured by the Center of Epidemiological Studies Depression Scale (CES-D) of 1288 survey respondents. We then retrieve county-level characteristics from the 2010 Chinese Population Census that match the individual characteristics in the survey, so as to create a profile of the "average person" for each of the 2869 counties or city districts, and predict a county-specific CES-D score. We use this county-specific CES-D score to compute the CES-D score for the urban population at the prefectural level, and to demonstrate the dramatic spatial variations in urbanization and mental health across China: highly populated cities along the eastern coast such as Shenyang and Shanghai show high CES-D scores, as do cities in western China with high population density and a high proportion of educated ethnic minorities.

Using a 2011 national survey of urban residents, irrespective of their official hukou status, and the 2000–2009 night-time light data from the Defense Meteorological Satellite Program Operational Linescan System (DMSP-OLS), this paper goes beyond the simple dichotomy of migrant versus non-migrant or rural versus urban hukou to disentangle the processes of urbanization and migration and their complex associations with health, and assesses the impact of various levels and speed of urbanization on the physical and mental health of current residents in a city or town. By disaggregating urbanization into three discrete dimensions at sub-provincial levels, we find that while a higher absolute level of urbanization at the county level negatively impacted self-reported physical health, faster and accelerating urbanization had a positive impact which could be attributed to the demand-pull effect underlying the healthy migrant phenomenon. By contrast, all three dimensions of urbanization were associated with greater depressive distress and thus had an adverse effect on residents' mental health. Beyond demonstrating how variation in the process and location of urbanization affects individual health, we also illustrate more broadly the value of modelling locational parameters in analyses of individual outcomes based on national samples.

We argue that interjurisdiction competition in authoritarian regimes engenders a specific logic for taxation. Promotion-seeking local officials are incentivized to signal loyalty and competence to their principals through tangible fiscal revenues. The greater the number of officials accountable to the same principal, the more intense political competition is, resulting in higher taxation; however, too many officials accountable to the same principal leads to lower taxation due to shirking by uncompetitive officials and the fear of political instability. Using a panel dataset of all Chinese county-level jurisdictions from 1999–2006, we find strong evidence for an inverse U-shaped relationship between the number of county-level jurisdictions within a prefecture—our proxy for the intensity of political competition—and fiscal revenues in most provinces but not so in politically unstable ethnic minority regions. The results are robust to various alternative specifications, including models that account for heterogeneous county characteristics and spatial interdependence.

Recent scholarship suggests that authoritarian leaders may use seemingly democratic institutions to strengthen their own rule. In this vein, China’s leaders attempted to rein in local governments by introducing new transparency regulations, with environmental transparency a key focus. However, implementing these requirements necessitates cooperation from the very actors who may be weakened by them. Surprisingly, more industrial or more polluted cities were no slower in implementing environmental transparency than cleaner ones, with pollution measured using satellite data in order to avoid relying on questionable official sources. However, cities dominated by large industrial firms lagged in implementing environmental transparency, and this effect appears strongest when a city’s largest firm is in a highly polluting industry. Our findings demonstrate that even institutional innovations designed to preserve authoritarian rule can face significant challenges of implementation.

Using data corresponding to an integrated luminosity of 79 pb-1, D0 has searched for events containing multiple jets and large missing transverse energy in pbar-p collisions at sqrt(s)=1.8 TeV at the Fermilab Tevatron collider. Observing no significant excess beyond what is expected from the standard model, we set limits on the masses of squarks and gluinos and on the model parameters m_0 and m_1/2, in the framework of the minimal low-energy supergravity models of supersymmetry. For tan(beta) = 2 and A_0 = 0, with mu < 0, we exclude all models with m_squark < 250 GeV/c^2. For models with equal squark and gluino masses, we exclude m < 260 GeV/c^2., 10 pages, 3 figures, Submitted to PRL, Fixed typo on page bottom of p. 6 (QCD multijet background is 35.4 events)

We present results on dijet production via hard color-singlet exchange in proton-antiproton collisions at √s = 630 GeV and 1800 GeV using the DØ detector. The fraction of dijet events produced via color-singlet exchange is measured as a function of jet transverse energy, separation in pseudorapidity between the two highest transverse energy jets, and proton-antiproton center-of-mass energy. The results are consistent with a color-singlet fraction that increases with an increasing fraction of quark-initiated processes and inconsistent with two-gluon models for the hard color-singlet. © 1998 Published by Elsevier Science B.V. All rights reserved.

We present a measurement of the Drell-Yan cross section at high dielectron invariant mass using 120/pb of data collected in pbar-p collisions at sqrt(s) = 1.8 TeV by the D0 collaboration during 1992-96. No deviation from standard model expectations is observed. We use the data to set limits on the energy scale of quark-electron compositeness with common constituents. The 95% confidence level lower limits on the compositeness scale vary between 3.3 TeV and 6.1 TeV depending on the assumed form of the effective contact interaction., 6 pages, 2 figures, submitted to PRL

The DZERO detector is used to study proton-antiproton collisions at the 1800 GeV and 630 GeV center-of-mass energies available at the Fermilab Tevatron. To measure jets, the detector uses a sampling calorimeter composed of uranium and liquid argon as the passive and active media respectively. Understanding the jet energy calibration is not only crucial for precision tests of QCD, but also for the measurement of particle masses and the determination of physics backgrounds associated with new phenomena. This paper describes the energy calibration of jets observed with the DZERO detector at the two proton-antiproton center-of-mass energies in the transverse energy and pseudorapidity range ET>8 GeV and pseudorapidity, 94 pages with 52 figures (included in the 94 pages)

The purpose of this study was to determine how time pressure and emotion influenced people's information behavior when engaging in high stakes decision-making within the home buying domain. Employing an exploratory approach, 33 semi-structured interviews involving a timeline strategy, as well as 8 observations, were conducted with participants from the Seattle, Washington metropolitan area. Findings revealed that "information use" induced emotion, created a sense of time pressure and generated an interaction of the two factors, whereas "non-information use" behaviors such as information needs and information seeking were propelled by emotion and time pressure. The study also identified the emergent "information use by proxy" phenomenon wherein emotion prompted people to enlist trusted surrogates to use information for making decisions on their behalf. Further, findings show that emotion and time pressure have the ability to alter one's routine information behavior to that of a more impulsive or arbitrary approach. Copyright: Copyright is held by the author

We recently reported evidence implicating fatty-acid binding protein (Fabp) in the control of sleep and memory formation. We used Drosophila melanogaster to examine the relationship between sleep and memory through transgenic overexpression of mouse brain-Fabp, Fabp7, or the Drosophila Fabp homologue, (dFabp). The key findings are that, (1) a genetically induced increase in daytime consolidated sleep (naps) correlates with an increase in cognitive performance, and (2) a late “window” of memory consolidation occurs days after the traditionally understood “synaptic” consolidation. Exactly how Fabp-signaling may be involved in converting normal to enhanced long-term memory (LTM) is not known. Here we describe additional data which support relative subcellular compartmental localization of Fabp in regulating stage associations of different forms of memory in Drosophila. Anesthesia resistant memory (ARM) is a longer lasting memory that is produced by massed training, but unlike LTM produced by spaced trai...

According to the ‘pace-of-life’ syndrome hypothesis, differences in resting metabolic rate (RMR) should be genetically associated with exploratory behaviour. A large number of studies reported significant heritability for both RMR and exploratory behaviour, but the genetic correlation between the two has yet to be documented. We used a quantitative genetic approach to decompose the phenotypic (co)variance of several metabolic and behavioural measures into components of additive genetic, common environment and permanent environment variance in captive deer mice. We found significant additive genetic variance for two mass-independent metabolic measures (RMR and the average metabolic rate throughout the respirometry run) and two behavioural measures (time spent in centre and distance moved in a novel environment). We also detected positive additive genetic correlation between mass-independent RMR and distance moved (rA = 0.78 ± 0.23). Our results suggest that RMR and exploratory behaviour are functionally integrated traits in deer mice, providing empirical support for one of the connections within the pace-of-life syndrome hypothesis.

Village elections in China present scholars with the case of a single-party regime that allows voters to reject candidates regularly. Using a micro survey of 698 voters in 30 rural election districts, the authors demonstrate that when some candidates can lose, voters participate. A comparison of models of voter turnout and running for office further demonstrates that even when competition is structured to the benefit of party members, the perception of competition as choice between candidates is sufficient to engage voters and increase their perception that the electoral process is fair. These findings hold regardless of a respondent’s age, gender, membership in the Communist Party and Youth League, and general knowledge level and access to media. Village wealth and geographical isolation also do not demonstrate a strong substantive impact. One theoretical implication of these findings is that contested elections in authoritarian regimes may simultaneously strengthen demand for accountability and loyalty to the regime.

The response of the brain to addictive substances such as nicotine includes the rapid induction of genes that influence synaptic events. This response is different in adolescent brain, which continues to undergo synaptic remodeling in regions that include reward-associated corticolimbic areas. We report here that acute nicotine (0.4 mg/kg), but not cocaine or exposure to a novel environment, induces the expression of the dendritically targeted, corticolimbic mRNA Dendrin in specific regions of adolescent brain. Acute nicotine resulted in an increase in Dendrin mRNA levels in the adolescent prefrontal cortex that was not evident in adult animals. The induction in Dendrin mRNA was a rapid, short-lived transcriptional event that resulted in changes in Dendrin protein. For example, an increase in Dendrin protein levels following nicotine treatment paralleled enhanced Dendrin immunoreactivity in the dendrites of pyramidal neurons of somatosensory cortex. As Dendrin is an important component of cytoskeletal modifications at the synapse, these results suggest that nicotine influences unique plasticity-related changes in the adolescent forebrain that differ from the adult.

Using a 2004 survey of over 1,000 children in a multi-ethnic county of Yunnan province, this article demonstrates how household and village assets operate in gender distinct ways to promote school enrolment in an era of economic privatization and skewed sex ratios. As expected, parental and village wealth facilitate enrolment, but parental wealth is far more decisive for girls than boys. Similarly we find a gender difference in the impact of such parental cultural capitals as education and membership in the Communist Youth League. For a daughter, having a father with higher than average levels of education and past membership in the Youth League facilitates enrolment independent of household wealth; for sons the impact of father's cultural capital is positive but less decisive. Having a more educated mother or a mother who was in the Youth League also promotes a child's enrolment but not as significantly as father's assets. In conclusion, the article considers why parents' involvement in the Youth League during their own adolescence but not their current Communist Party membership facilitates school enrolment, and the broader social and political implications for the role of the Communist Party in rural society.

Political selection is central to the survival of all regimes. This article evaluates the relative importance of performance and political connection for the advancement of local politicians under authoritarianism. We hypothesize that in a large-scale multilevel polity, economic performance plays a greater role in promotion at lower administrative levels of government than at higher ones, even after controlling for political connections. This dualist strategy allows the ruling elites to achieve economic performance while minimizing the advancement of potentially disloyal challengers. Thus, balancing between loyalty and competence among subordinates enhances regime survival. Our empirical evidence draws on a comprehensive panel dataset of provincial, prefectural, and county-level Communist party secretaries and government executives appointed between 1999 and 2007. We find consistent evidence for our argument under various model specifications. We also explore the heterogeneous effects of performance on promotion given the Chinese Communist Party’s (CCP) age ineligibility rule for cadre promotion and jurisdiction characteristics.

In order to survive, animals must acquire information about the reward value of stimuli in their environment. This process partly depends on the ability of the organism to make associations between the environmental context and the internal representation of value. While this type of learning probably evolved in order to promote behaviors that increase fitness (e.g., ingestive and sexual behavior), neuropsychological research utilizing addictive drugs, which are potent artificial reinforcers, has led to a deeper understanding of reinforcement mechanisms. Through these associations, sensory cues can acquire emotional salience and motivational properties. Exposure to drug-related cues in human addicts results in drug craving and localized activation of central circuits that are known to mediate cue-induced reinstatement of drug-seeking behavior in animal models of relapse. Similar regional activation patterns occur in humans in response to cues associated with foods. Furthermore, drug- and food-related cues not only activate common neuroanatomical regions but also result in similar activity-regulated gene expression programs within these shared areas. Here we discuss recent studies from our laboratory that investigate gene expression patterns elicited by exposure to palatable food- or drug-related cues. These studies suggest that the central nervous system stores and utilizes information about 'natural' and drug reinforcers in similar ways, both neuroanatomically and biochemically. These considerations may have important implications for the pharmacological and cognitive-behavioral treatments of substance use disorders, addiction, eating disorders, and obesity.

Cytoplasmic polyadenylation is important in the control of mRNA stability and translation, and for early animal development and synaptic plasticity. Here, we focus on vertebrate poly(A) polymerases that are members of the recently described GLD2 family. We identify and characterize two closely related GLD2 proteins in Xenopus oocytes, and show that they possess PAP activity in vivo and in vitro and that they bind known polyadenylation factors and mRNAs known to receive poly(A) during development. We propose that at least two distinct polyadenylation complexes exist in Xenopus oocytes, one of which contains GLD2; the other, maskin and Pumilio. GLD2 protein interacts with the polyadenylation factor, CPEB, in a conserved manner. mRNAs that encode GLD2 in mammals are expressed in many tissues. In the brain, mouse, and human GLD2 mRNAs are abundant in anatomical regions necessary for long-term cognitive and emotional learning. In the hippocampus, mouse GLD2 mRNA colocalizes with CPEB1 and Pumilio1 mRNAs, both of which are likely involved in synaptic plasticity. We suggest that mammalian GLD2 poly(A) polymerases are important in synaptic translation, and in polyadenylation throughout the soma.

Conditioned responses to cues associated with the administration of drugs of misuse are an impediment to continued abstinence for drug-free addicted individuals. In order to study the neuroanatomical and cellular response of the brain to cues associated with nicotine administration, we conditioned Sprague-Dawley rats to receive an ascending dose regimen of nicotine over 14 days in two distinct non-home cage environments and assessed expression of the early response gene arc in corticolimbic areas in response to the nicotine-associated context. All of the rats received the same dose regimen of nicotine. Three days after the last training day, the rats were exposed to the test environment. The rats that had previously received nicotine exhibited increased motor activity compared with the rats that had received saline in the test environment. After 45 min in the test environment, brains were taken for Northern blotting and in situ hybridization analysis, which revealed an increase in levels of activity-regulated, dendritically localized mRNA for arc in a variety of brain regions (medial and lateral prefrontal cortices, cingulate cortex, primary sensory cortex, sensorimotor cortex, ventral striatum and amygdala). Plasma corticosterone levels were not different between the groups, suggesting that exposure to nicotine cues is insufficient to activate the hypothalamo-pituitary-adrenal axis. Given that Arc plays a direct role in neuronal plasticity and memory consolidation, its induction by nicotine-associated cues in brain regions critical for cognitive and emotional processing suggests that rats may be learning that these cues are no longer necessarily predictive of nicotine administration. Further work will be needed in order to assess the role of arc expression in the extinction of conditioned responses to drug-paired cues.

List-based samples are often biased because of coverage errors. The problem is especially acute in societies where the level of internal migration is high and where record keeping on the population is not reliable. We propose a solution based on spatial sampling that overcomes the inability to reach migrants in traditional area samples based on household lists. A comparison between a traditional study and our sample of Beijing demonstrates that coverage bias is greatly reduced. The successful incorporation of mobile urban residents has important substantive effects, in both univariate and multivariate analyses of public opinion data.

Relatively little attention has been focused on mechanisms related to neural plasticity and drug abuse in adolescence, compared with abundant research using adult animal models. As smoking is typically initiated in adolescence, an important question to address is whether the adolescent brain responds differently to nicotine compared with the adult. To investigate this question, we examined the expression of a number of early response genes (arc, c-fos and NGFI-B) that have been implicated in synaptic plasticity and addiction, following acute nicotine in adolescent and adult rats. Baseline expression of arc and c-fos was higher in adolescent brains compared with adults. Following acute nicotine treatment (0.1, 0.4 mg/kg), we found a marked induction of arc mRNA in the prefrontal cortex of nicotine-treated adolescents compared with a less pronounced increase of arc in the adult. c-fos and NGFI-B were also upregulated by nicotine, but not in an age-related manner. In contrast, nicotine induced less arc, c-fos, and NGFI-B expression in the somatosensory cortex of adolescents compared with adults. A fourth gene, quinoid dihydropteridine reductase was expressed at lower levels in white matter of the adolescent forebrain compared with the adult, but was not affected by nicotine. These results suggest that in adolescence, the activity of specific early response genes is higher in brain regions critical for emotional regulation and decision-making. Further, nicotine affects key plasticity molecules in these areas in a manner different from the adult. Thus, adolescence may represent a neurobiologically vulnerable period with regard to nicotine exposure.

Hypocretin/orexin (H/O) and melanin-concentrating hormone (MCH) are peptide neuromodulators found in separate populations of neurons located within the lateral and perifornical hypothalamic regions. H/O has been linked to sleep-wakefulness regulation and to the sleep disorder narcolepsy, and both systems have been implicated in energy homeostasis, including the regulation of food intake. In the present study we compared the development of H/O and MCH-expressing neuronal populations with in situ hybridization and immunohistochemistry on adjacent sections in the embryonic and postnatal rat brain. We found that MCH mRNA and protein were present in developing neurons of the hypothalamus by embryonic day 16 (E16), whereas H/O mRNA and protein were not detected until E18. We also identified previously undescribed populations of MCH-immunoreactive cells in the lateral septum, paraventricular hypothalamic nucleus, lateral zona incerta, and ventral lateral geniculate nucleus that may play a specific role in the development of these regions. MCH immunoreactive axonal processes were also evident earlier than H/O stained fibers and at the time H/O immunoreactive processes were first identified in the hypothalamus at E20, extensive MCH axonal fiber systems were already present in many brain regions. Interestingly, however, the density of axonal fibers immunoreactive for H/O in the locus coeruleus reached peak levels at the same developmental age (P21) as MCH immunoreactive axons in the diagonal band of Broca (DBB). The peak of axon density coincided with the developmental stage at which adult patterns of feeding and sleep–waking activity become established. The present results demonstrate developmental differences and similarities between the MCH and H/O systems that may relate to their respective roles in feeding and sleep regulation.

Risk taking and novelty seeking are hallmarks of typical adolescent behavior. Adolescents seek new experiences and higher levels of rewarding stimulation, and often engage in risky behaviors, without considering future outcomes or consequences. These behaviors can have adaptive benefits with regard to the development of independence and survival without parental protection, but also render the adolescent more vulnerable to harm. Indeed, the risk of injury or death is higher during the adolescent period than in childhood or adulthood, and the incidence of depression, anxiety, drug use and addiction, and eating disorders increases. Brain pathways that play a key role in emotional regulation and cognitive function undergo distinct maturational changes during this transition period. It is clear that adolescents think and act differently from adults, yet relatively little is known about the precise mechanisms underlying neural, behavioral, and cognitive events during this period. Increased investigation of these dynamic alterations, particularly in prefrontal and related corticolimbic circuitry, may aid this understanding. Moreover, the investigation of mammalian animal models of adolescence-such as those examining impulsivity, reward sensitivity, and decision making-may also provide new opportunities for addressing the problem of adolescent vulnerability.

In this paper, a Windows PC-program is described that performs the transformation of measurement spectra obtained by resonant nuclear reaction analysis (RNRA) into concentration depth profiles. For the shape of the resonance a simple Breit–Wigner form is implemented. For the calculation of the straggling both the Bohr and the Lindhard–Scharff models can be used. The program can be used to evaluate depth profiles of an element in an otherwise homogeneous target. A nanometer depth scale is obtained by considering the concentration-dependent densities of the phases. This is exploited for the investigation of nitrogen profiles via the resonance reaction 15 N ( p , αγ ) 12 C . For demonstration purposes the program is used to determine nitrogen depth profiles of laser nitrided iron.

Laser nitriding is a very efficient method to improve the mechanical properties, surface hardness, corrosion, and wear resistance of iron and steel, with the advantages of a high nitrogen concentration, fast treatment, and accurate position control, and without any undesired heating effect on the substrate. However, the stability of laser-produced iron nitrides is still under investigation. This article reports investigations of the thermal stability of these iron nitrides upon annealing treatments, which were conducted both in vacuum and air. The phase and elemental composition of the nitride layers were deduced from conversion electron Mossbauer spectroscopy, resonant nuclear reaction analysis, and grazing incidence x-ray diffraction. The surface hardness was measured by the nanoindentation method. In laser-nitrided iron, two critical temperatures are found: at 523 K the predominant iron-nitride phase changes from the γ/e to the γ′ phase. When the temperature exceeds 773 K, all of the nitrogen has escap...

In three experiments, bumble bees were trained to discriminate between a reinforcing pattern (S+) and a nonreinforcing one (S−) which differed only in the configuration of four artificial petals. They were subsequently tested for recognition of the S+ rotated by 90° (S + 90). Experiment 1 used petals of four colors, and the other experiments used four symbols. The symbols either remained unchanged when the whole pattern was rotated (e.g., “+” in Experiment 2) or changed appearance (e.g., “

Mossbauer spectroscopy is a very powerful tool to investigate technological processes performed mainly at the surface of materials. Nitriding of metals and steel is well established in surface engineering, and gas nitriding is used most frequently. Laser nitriding, i.e. the nitrogen take-up from the ambient gas upon irradiation of a steel surface with short laser pulses, is presented in its application to iron, stainless steel and plain carbon steels. It will be demonstrated how Mossbauer spectroscopy in combination with complementary methods (Rutherford backscattering spectroscopy, Resonant nuclear reaction analysis, Nanoindentation) can help to reveal basic mechanisms in these processes.

Drug-associated contextual cues can exert a powerful influence on be- havior through associative pairing between the drug and the environment. However, the anatomical and molecular substrates for these effects are not well characterized. Using a drug-conditioning paradigm, we examined the expression of the immediate early gene product, Fos, within specific brain circuits using immunocytochemical detection. Rats were given either morphine (5 mg/ml/kg) or saline once a day for 10 days. The drug administration was always paired with a specific environment (activity monitors) dif- ferent from the home cage. Following this treatment, the rats were returned to the cages at various times thereafter, with only a mock injection. Conditioned behavioral activa- tion was observed in rats at 3, 5, and 7 days following treatment with morphine. In rats showing the conditioned motor response, several cortical and limbic areas showed substantial increases in the number of Fos positive cells, indicating that these regions were more active during exposure to the drug-paired environment. Areas that were most activated included prefrontal cortex, cingulate cortex, nucleus accumbens, and preoptic area. Further analysis showed that this increase in Fos expression was not directly related to the increase in motor activity, and that the drug-associated conditioning and Fos expression was lessened at 7 days and absent by 14 days post-treatment. These results are discussed in terms of their relevance to the problem of relapse in drug addiction. Synapse 37:146 -158, 2000. © 2000 Wiley-Liss, Inc.

This Letter describes a measurement of the muon cross section originating from b quark decay in the forward rapidity range 2.4 < y(mu) < 3.2 in pbarp collisions at sqrt(s) = 1.8 TeV. The data used in this analysis were collected by the D0 experiment at the Fermilab Tevatron. We find that NLO QCD calculations underestimate b quark production by a factor of four in the forward rapidity region. A cross section measurement using muon+jet data has been included in this version of the paper.

We present a measurement of the transverse momentum distribution of Z bosons produced in ppbar collisions at sqrt{s}=1.8 TeV using data collected by the D0 experiment at the Fermilab Tevatron Collider during 1994--1996. We find good agreement between our data and a current resummation calculation. We also use our data to extract values of the non-perturbative parameters for a particular version of the resummation formalism, obtaining significantly more precise values than previous determinations.

Most metals can be nitrided by irradiation with short pulses of an excimer laser in nitrogen containing atmospheres. By the laser nitriding process with a XeCl excimer laser beam (wavelength λ=308 nm, average energy density H=4 J/cm2, pulse width τ=55 ns) in pure nitrogen, iron nitride coatings of 1–2 μm thickness at a level of up to 15 at.% nitrogen were produced. The results of the complicated laser-plasma-material interaction can be resolved by combining Resonant nuclear reaction analysis (RNRA) and Rutherford backscattering spectrometry (RBS). Utilizing the exclusive sensitivity of RNRA to the isotope 15N, RNRA via the 15N(p,αγ)12C resonance reaction and alternate irradiations in a N2 atmosphere of natural or enriched 15N abundance are employed to study the take-up of new nitrogen into the surface and the transport mechanisms upon irradiation with subsequent pulses. Together with RBS investigations of convective transport of the molten base material using thin Au marker layers, information on basic mechanisms of the nitriding process (convection, diffusion) was gained enabling a simulation of the nitrogen depth profiles.

SUMMARYThe effect of resource deprivation (pollen and nectar) on individual foraging behaviour by bumble bees (Bombus impatiens) from two colonies was examined. For the first colony, the same three workers were observed on blueberry flowers (Vaccinium angustifolium) in the laboratory in three conditions: (1) deprived of nectar; (2) deprived of pollen; (3) deprived of both. We distinguished between flower visits in which vibrating the anthers (buzzing) for pollen either was or was not observed. The proportion of buzzes was greater when the colony was deprived of pollen than when it was deprived of nectar. When deprived of both resources, pollen collection behaviour was yet more frequent, suggesting that pollen can serve, at least in part, as a substitute for nectar. For the second colony, a group of 15 bees was used. Four to eight bees were observed for each of the three conditions. Group proportions of buzzing were significantly higher in the pollen deprivation than in the nectar deprivation condition. Th...