bluuebunny/crossref_metadata_2025 huggingface dataset:
AT1 and glutamatergic receptors in paraventricular nucleus support blood pressure during water deprivation
Authors: Freeman Korrina L. , Brooks Virginia L.
Published: December 2006

Water deprivation activates sympathoexcitatory neurons in the paraventricular nucleus (PVN); however, the neurotransmitters that mediate this activation are unknown. To test the hypothesis that ANG II and glutamate are involved, effects on blood pressure (BP) of bilateral PVN microinjections of ANG II type 1 receptor (AT1R) antagonists, candesartan and valsartan, or the ionotropic glutamate receptor antagonist, kynurenate, were determined in urethane-anesthetized water-deprived and water-replete male rats. Because PVN may activate sympathetic neurons via the rostral ventrolateral medulla (RVLM) and because PVN disinhibition increases sympathetic activity in part via increased drive of AT1R in the RVLM, candesartan was also bilaterally microinjected into the RVLM. Total blockade of the PVN with bilateral microinjections of muscimol, a GABAA agonist, decreased BP more ( P < 0.05) in water-deprived (−29 ± 8 mmHg) than in water-replete (−7 ± 2 mmHg) rats, verifying that the PVN is required for BP maintenance during water deprivation. PVN candesartan slowly lowered BP by 7 ± 1 mmHg ( P < 0.05). In water-replete rats, however, candesartan did not alter BP (1 ± 1 mmHg). Valsartan also produced a slowly developing decrease in arterial pressure (−6 ± 1 mmHg; P < 0.05) in water-deprived but not in water-replete (−1 ± 1 mmHg) rats. In water-deprived rats, PVN kynurenate rapidly decreased BP (−19 ± 3 mmHg), and the response was greater ( P < 0.05) than in water-replete rats (−4 ± 1 mmHg). Finally, as in PVN, candesartan in RVLM slowly decreased BP in water-deprived (−8 ± 1 mmHg; P < 0.05) but not in water-replete (−3 ± 1 mmHg) rats. These data suggest that activation of AT1 and glutamate receptors in PVN, as well as of AT1R in RVLM, contributes to BP maintenance during water deprivation.
Renal compensation to chronic hypoxic hypercapnia: downregulation of pendrin and adaptation of the proximal tubule
Authors: de Seigneux Sophie , Malte Hans , Dimke Henrik , Frøkiær Jørgen , Nielsen Søren , Frische Sebastian
Published: December 2006

The molecular basis for the renal compensation to respiratory acidosis and specifically the role of pendrin in this condition are unclear. Therefore, we studied the adaptation of the proximal tubule and the collecting duct to respiratory acidosis. Male Wistar-Hannover rats were exposed to either hypercapnia and hypoxia [8% CO2and 13% O2(hypercapnic, n = 6) or normal air (controls, n = 6)] in an environmental chamber for 10 days and were killed under the same atmosphere. In hypercapnic rats, arterial pH was lower than controls (7.31 ± 0.01 vs. 7.39 ± 0.01, P = 0.03), blood HCO3−concentration was increased (42 ± 0.9 vs. 32 ± 0.24 mM, P < 0.001), arterial Pco2was increased (10.76 ± 0.4 vs. 7.20 ± 0.4 kPa, P < 0.001), and plasma chloride concentration was decreased (92.2 ± 0.7 vs. 97.2 ± 0.5 mM, P < 0.001). Plasma aldosterone levels were unchanged. In the proximal tubule, immunoblotting showed an increased expression of sodium/bicarbonate exchanger protein (188 ± 22 vs. 100 ± 11%, P = 0.005), confirmed by immunohistochemistry. Total Na/H exchanger protein expression in the cortex was unchanged by immunoblotting (119 ± 10 vs. 100 ± 11%, P = 0.27) and immunohistochemistry. In the cortex, the abundance of pendrin was decreased (51 ± 9 vs. 100 ± 7%, P = 0.003) by immunoblotting. Immunohistochemistry revealed that this decrease was clear in both cortical collecting ducts (CCDs) and connecting tubules (CNTs). This demonstrates that pendrin expression can be regulated in acidotic animals with no changes in aldosterone levels and no external chloride load. This reduction of pendrin expression may help in redirecting the CNT and CCD toward chloride excretion and bicarbonate reabsorption, contributing to the increased plasma bicarbonate and decreased plasma chloride of chronic respiratory acidosis.
Subthalamic and Striatal Neurons Concurrently Process Motor, Limbic, and Associative Information in Rats Performing an Operant Task
Authors: Teagarden Mark A. , Rebec George V.
Published: December 2006

Although the subthalamic nucleus (STN) is commonly assumed to be a relay for striatal (STR) output, anatomical evidence suggests the two structures are connected in parallel, raising the possibility that parallel STN and STR firing patterns mediate behavioral processes. The STR is known to play a role in associative and limbic processes, and although behavioral studies suggest that the STN may do so as well, evaluation of this hypothesis is complicated by a lack of pertinent STN physiological data. We recorded concurrent STN and STR firing patterns in rats learning an operant nose-poke task. Both structures responded in similar proportions to task events including instructive cues, discriminative nose-pokes, and sucrose reinforcement. Neuronal responses to reinforcement comprised phasic excitations preceding reinforcement and inhibitions afterward; the inhibition was attenuated when reinforcement was absent. Reinforcement responses occurred more frequently during later training sessions in which discriminative action was required, suggesting that responses were context-dependent. Nose-pokes were typically preceded by excitations; there also was a nonsignificant trend toward inhibition encoding correct nose-pokes. Sustained changes in firing rate coinciding with specific task events suggested that both nuclei were encoding behavioral sequences; this is the first report of such behavior in the STN. Our findings also reveal complex STN responses to reinforcement. Thus both STN and STR neurons show concurrent involvement in motor, limbic, and associative processes.
NK-1 Receptors Modulate the Excitability of on Cells in the Rostral Ventromedial Medulla
Authors: Budai Dénes , Khasabov Sergey G. , Mantyh Patrick W. , Simone Donald A.
Published: December 2006

The role of neurokinin-1 (NK-1) receptors in the rostral ventromedial medulla (RVM) was studied using extracellular single-unit recording combined with microiontophoresis. In rats, on- and off-type neurons were identified using noxious heat or mechanical stimuli applied to the tail. Responses evoked by iontophoretic application of N-methyl-d-aspartate (NMDA) were determined before and after intraplantar injection of capsaicin or iontophoretic application of substance P. In off cells, capsaicin produced an extended pause in ongoing activity but did not alter the subsequent spontaneous discharge rate or NMDA-evoked responses. In contrast, spontaneous discharge rates of on cells increased after capsaicin, and their responses to NMDA increased >100% above control values. The increased responses to NMDA after capsaicin were attenuated by iontophoretic application of the selective NK-1 receptor antagonist L-733,060. Similarly to capsaicin, iontophoretic application of the selective NK-1 receptor agonist, [Sar9,Met(O2)11]-substance P (SM-SP), increased the spontaneous discharge rate and NMDA-evoked responses of on cells by >100% of control values. These effects were antagonized by L-733,060. Immunohistochemical studies showed that a subset of neurons in the RVM labeled NK-1 receptors and that nearly all of these neurons were immunoreactive for the NMDAR1 subunit of the NMDA receptor. These results demonstrate that activation of NK-1 receptors in the RVM enhances responses of on cells evoked by NMDA. It is suggested that activation of NK-1 receptors in the RVM and the ensuing sensitization of on cells may contribute to the development of central sensitization and hyperalgesia after tissue injury and inflammation.
Responses of Single Neurons in Monkey Amygdala to Facial and Vocal Emotions
Authors: Kuraoka Koji , Nakamura Katsuki
Published: December 2006

The face and voice can independently convey the same information about emotion. When we see an angry face or hear an angry voice, we can perceive a person's anger. These two different sensory cues are interchangeable in this sense. However, it is still unclear whether the same group of neurons process signals for facial and vocal emotions. We recorded neuronal activity in the amygdala of monkeys while watching nine video clips of species-specific emotional expressions: three monkeys showing three emotional expressions (aggressive threat, scream, and coo). Of the 227 amygdala neurons tested, 116 neurons (51%) responded to at least one of the emotional expressions. These “monkey-responsive” neurons—that is, neurons that responded to monkey-specific emotional expression—preferred the scream to other emotional expressions irrespective of identity. To determine the element crucial to neuronal responses, the activity of 79 monkey-responsive neurons was recorded while a facial or vocal element of a stimulus was presented alone. Although most neurons (61/79, 77%) strongly responded to the visual but not to the auditory element, about one fifth (16/79, 20%) maintained a good response when either the facial or vocal element was presented. Moreover, these neurons maintained their stimulus-preference profiles under facial and vocal conditions. These neurons were found in the central nucleus of the amygdala, the nucleus that receives inputs from other amygdala nuclei and in turn sends outputs to other emotion-related brain areas. These supramodal responses to emotion would be of use in generating appropriate responses to information regarding either facial or vocal emotion.
Skill Representation in the Primary Motor Cortex After Long-Term Practice
Authors: Matsuzaka Yoshiya , Picard Nathalie , Strick Peter L.
Published: December 2006

The acquisition of motor skills can lead to profound changes in the functional organization of the primary motor cortex (M1). For example, performance of movement sequences after prolonged practice is associated with an expansion of the effector representation in M1. Paradoxically, there is little evidence that the activity of M1 neurons reflects acquired skills, especially sequences of movements. We examined the activity of M1 neurons during skilled movement sequences in macaques trained to successively hit targets on a monitor. The targets appeared either pseudorandomly (Random mode) or in one of two repeating sequences (Repeating mode). With practice, response times for repeating sequences substantially declined and the monkeys performed the task predictively. Highly trained animals retained the acquired skill after long gaps in practice. After >2 yr of training, 40% of M1 neurons were differentially active during the two task modes. Variations in movement kinematics did not fully explain the task-dependent modulation of neuron activity. Differentially active neurons were more strongly influenced by task mode than by kinematics. Our results suggest that practice sculpts the response properties of M1 neurons. M1 may be a site of storage for the internal representation of skilled sequential movements.
Neural Coding Mechanisms for Flow Rate in Taste-Responsive Cells in the Nucleus of the Solitary Tract of the Rat
Authors: Lorenzo Patricia M. Di , Victor Jonathan D.
Published: December 2006

When a taste stimulus enters the mouth, intentional movement of the stimulus within the oropharyngeal cavity affects the rate at which taste receptors are exposed to the stimulus and may ultimately affect taste perception. Early studies have shown that stimulus flow rate, the experimental equivalent of the effects of these investigative movements, modulates the portion of the peripheral nerve response that occurs when behavioral assessments of tastants are made. The present experiment studied the neural coding mechanisms for flow rate in the nucleus of the solitary tract (NTS), the first central relay in the taste pathway. Responses to NaCl (0.1 M) presented at high (5 ml/s) and low (3 ml/s) flow rates, sucrose (0.5 M), quinine HCl (0.01 M), and HCl (0.01 M) were recorded extracellularly from single NTS units in multiple replications. Information conveyed by evoked responses was analyzed with a family of metrics that quantify the similarity of two spike trains in terms of spike count and spike timing. Information about flow rate was conveyed by spike timing and spike count in approximately equal proportions of units (each ∼1/3), whereas information about taste quality was conveyed by spike timing in about half of the units. Different subsets of units contributed information for discrimination of flow rate and taste quality.
Bayesian Analysis of Interleaved Learning and Response Bias in Behavioral Experiments
Authors: Smith Anne C. , Wirth Sylvia , Suzuki Wendy A. , Brown Emery N.
Published: December 2006

Accurate characterizations of behavior during learning experiments are essential for understanding the neural bases of learning. Whereas learning experiments often give subjects multiple tasks to learn simultaneously, most analyze subject performance separately on each individual task. This analysis strategy ignores the true interleaved presentation order of the tasks and cannot distinguish learning behavior from response preferences that may represent a subject's biases or strategies. We present a Bayesian analysis of a state-space model for characterizing simultaneous learning of multiple tasks and for assessing behavioral biases in learning experiments with interleaved task presentations. Under the Bayesian analysis the posterior probability densities of the model parameters and the learning state are computed using Monte Carlo Markov Chain methods. Measures of learning, including the learning curve, the ideal observer curve, and the learning trial translate directly from our previous likelihood-based state-space model analyses. We compare the Bayesian and current likelihood–based approaches in the analysis of a simulated conditioned T-maze task and of an actual object–place association task. Modeling the interleaved learning feature of the experiments along with the animal's response sequences allows us to disambiguate actual learning from response biases. The implementation of the Bayesian analysis using the WinBUGS software provides an efficient way to test different models without developing a new algorithm for each model. The new state-space model and the Bayesian estimation procedure suggest an improved, computationally efficient approach for accurately characterizing learning in behavioral experiments.
Singing-Related Activity of Identified HVC Neurons in the Zebra Finch
Authors: Kozhevnikov Alexay A. , Fee Michale S.
Published: December 2006

High vocal center (HVC) is part of the premotor pathway necessary for song production and is also a primary source of input to the anterior forebrain pathway (AFP), a basal ganglia-related circuit essential for vocal learning. We have examined the activity of identified HVC neurons of zebra finches during singing. Antidromic activation was used to identify three classes of HVC cells: neurons projecting to the premotor nucleus RA, neurons projecting to area X in the AFP, and putative HVC interneurons. HVC interneurons are active throughout the song and display tonic patterns of activity. Projection neurons exhibit highly phasic stereotyped firing patterns. X-projecting (HVC(X)) neurons burst zero to four times per motif, whereas RA-projecting neurons burst extremely sparsely—at most once per motif. The bursts of HVC projection neurons are tightly locked to the song and typically have a jitter of <1 ms. Population activity of interneurons, but not projection neurons, was significantly correlated with syllable patterns. Consistent with the idea that HVC codes for the temporal order in the song rather than for sound, the vocal dynamics and neural dynamics in HVC occur on different and uncorrelated time scales. We test whether HVC(X)neurons are auditory sensitive during singing. We recorded the activity of these neurons in juvenile birds during singing and found that firing patterns of these neurons are not altered by distorted auditory feedback, which is known to disrupt learning or to cause degradation of song already learned.
Heschl's Gyrus, Posterior Superior Temporal Gyrus, and Mid-Ventrolateral Prefrontal Cortex Have Different Roles in the Detection of Acoustic Changes
Authors: Schönwiesner Marc , Novitski Nikolai , Pakarinen Satu , Carlson Synnöve , Tervaniemi Mari , Näätänen Risto
Published: December 2006

A part of the auditory system automatically detects changes in the acoustic environment. This preattentional process has been studied extensively, yet its cerebral origins have not been determined with sufficient accuracy to allow comparison to established anatomical and functional parcellations. Here we used event-related functional MRI and EEG in a parametric experimental design to determine the cortical areas in individual brains that participate in the detection of acoustic changes. Our results suggest that automatic change processing consists of at least three stages: initial detection in the primary auditory cortex, detailed analysis in the posterior superior temporal gyrus and planum temporale, and judgment of sufficient novelty for the allocation of attentional resources in the mid-ventrolateral prefrontal cortex.
Placing pain on the sensory map: Classic papers by Ed Perl and colleagues
Authors: Mason Peggy
Published: December 2006

This essay looks at two papers published by Ed Perl and co-workers that identified specifically nociceptive neurons in the periphery and superficial dorsal horn.

Bessou P and Perl ER. Response of cutaneous sensory units with unmyelinated fibers to noxious stimuli. J Neurophysiol 32: 1025–1043 1969.

Christensen BN and Perl ER. Spinal neurons specifically excited by noxious or thermal stimuli: marginal zone of the dorsal horn. J Neurophysiol 33: 293–307 1970.
New Stakes and Standards, Same Ol' Spending? Evidence from New York City High Schools
Authors: Iatarola Patrice , Rubenstein Ross
Published: December 2006

In 1996, New York State began requiring all graduating high school students (starting with the Class of 1999) to pass rigorous end-of-course exams in five subjects. This study explores whether high school resources have been reallocated in the wake of these new standards and whether reallocation patterns differ among high- and low-graduation-rate schools. Using a six-year panel of school-level data, we model resources as a function of school and student characteristics, school graduation rates, and school fixed effects. Regression analyses reveal increases in direct services spending, while the percentage of more experienced and educated teachers fell. We find little evidence, though, of differential patterns related to graduation rates, with the exception of teacher licensure and nonpersonnel expenditures. The findings suggest that schools may have limited ability to redeploy nonteacher resources in the short term. While other funds may be reallocated, these represent a small share of total school resources.
The Political Economy of Antiretroviral Drugs in Zambia
Authors: Bwalya Edgar
Published: December 2006

According to the 2005 United Nations Programe on HIV/AIDS (UNAIDS) and the World Health Organization (WHO) Report, Zambia has one of the highest rates of HIV/AIDS cases in Southern Africa as well as in the world. However, it is also one of the few countries that have recorded a drop in the infection rates from an estimated 26% of the population in 2000 to just fewer than 16% in 2005. There appears to be a general consensus that the availability and free provision of antiretroviral drugs (ARVs) and treatment have raised hope that the recipients will live a longer, improved, and productive life. This paper will attempt to assess the major challenges to scaling-up antiretroviral therapy in Zambia. It argues that, while the government has made some progress in scaling-up access to ARVs, there is still much to be done.
The Well-Being of Industrial Workers: A Quantitative Assessment of the Dominican Case
Authors: Liberato Ana , Fennell Dana
Published: December 2006

This paper examines the influence of gender and industrial employment on two dimensions of well-being. An analysis based on the 1996 DHS survey showed the non-significant effects of the two variables on material wealth and housing quality. Key factors in increasing household well-being were urban location, household labor, and education. Urban location showed the largest positive effect on well-being. The Chi-square test showed a significant relationship between free trade zone employment and access to durable goods (P ≤ 0.5). These findings show the larger impact of specific demographic conditions on women's well-being, favoring contextual analysis over exploitation and opportunity frameworks.
Skilled Labor Immigration and External Trade in Malaysia: A Pooled Data Analysis
Authors: Hong Tan Chuie , Santhapparaj A. Solucis
Published: December 2006

This paper attempts to further the immigrant-link literature by applying, for the first time, gravity models to Malaysia. Specifically the paper seeks to quantify the impact upon Malaysia's bilateral trade flows of ASEAN and non-ASEAN skilled immigration, and to identify the underlying mechanisms underpinning this relationship. The results indicate that skilled immigration positively affects both the imports and exports of Malaysia. Immigrant-link is stronger between Malaysia and ASEAN countries than to non-ASEAN countries. The magnitude of the elasticity with respect to trade is larger for imports than for exports. Skilled immigrants' demand for native products outweighs the business-links formed between Malaysian trading partners.
Snowpack Variations in the Central Andes of Argentina and Chile, 1951–2005: Large-Scale Atmospheric Influences and Implications for Water Resources in the Region
Authors: Masiokas Mariano H. , Villalba Ricardo , Luckman Brian H. , Le Quesne Carlos , Aravena Juan Carlos
Published: December 2006

The snowpack in the central Andes (30°–37°S) is the primary source for streamflow in central Chile and central-western Argentina, but few published studies are available on snowpack variability in the region. This paper develops the first regional snowpack series (1951–2005) from Chilean and Argentinean snow course records. This series shows a strong regional signal, marked interannual variability, and a positive, though nonsignificant, linear trend. Correlations with local precipitation and temperature records reveal a marked association with conditions in central Chile. High snow accumulation is generally concurrent with El Niño events in the tropical Pacific, but only 5 of the 10 driest years coincided with La Niña events. Evaluation of 500-hPa geopotential height anomaly maps during extreme snow years highlights the crucial significance of tropospheric conditions in the subtropical and southeast Pacific in modulating snowfall. Correlations with gridded SST and SLP data and multiple regressions with large-scale climatic indices corroborate a Pacific ENSO-related influence largely concentrated during the austral winter months. This hampers the predictability of snowpack before the onset of the cold season. Annual and warm-season river discharges on both sides of the cordillera are significantly correlated with the regional snowpack record and show positive linear trends over the 1951–2004 common period, probably related to a greater frequency of above-average snowpacks during recent decades. Future demand and competition for water resources in these highly populated regions will require detailed information about temporal and spatial variations in snow accumulation over the Andes. The results indicate that the relationships between snowpack and atmospheric circulation patterns prior to the winter season are complex, and more detailed analyses are necessary to improve prediction of winter snowfall totals.
Changes in the Activity of the Madden–Julian Oscillation during 1958–2004
Authors: Jones Charles , Carvalho Leila M. V.
Published: December 2006

The Madden–Julian oscillation (MJO) is the most prominent mode of tropical intraseasonal variability. This study investigates the following questions. Is there statistical evidence of linear trends in MJO activity since the mid-1970s? Does the MJO exhibit changes in regimes of high and low activity? Are there significant seasonal differences in the activity of the MJO on time scales longer than interannual?

Positive linear trends are observed in zonal wind anomalies at 200 (U200) and 850 (U850) hPa during summer and winter seasons. Positive trends are also observed in the number of summer MJO events. Resampling statistical tests indicate that positive trends in summer U200 and U850 anomalies are statistically different from random occurrences at a 5% significance level.

A methodology based on the number of events is used to characterize low-frequency (LF) changes in MJO activity. Mean winter LF activity was characterized by nearly uniform variability from the early 1960s until the mid-1990s. In contrast, mean summer LF changes showed a regime of high activity from the mid-1960s until the late 1970s, a low regime from 1980 to 1988, and a regime of high activity from the early 1990s to early 2000. Fourier analysis of the mean summer LF index indicates that regimes of high MJO activity were separated by 18.5 yr. The substantial changes in summer MJO regimes do not appear to be related to increases in observational samplings due to satellite-derived winds assimilated in the NCEP–NCAR reanalysis. Monte Carlo experiments indicate that the observed changes in regimes of MJO activity in summer are statistically different from random occurrences at the 10% significance level only.
Ocean Surface Albedo and Its Impact on Radiation Balance in Climate Models
Authors: Li J. , Scinocca J. , Lazare M. , McFarlane N. , von Salzen K. , Solheim L.
Published: December 2006

An analysis of several ocean surface albedo (OSA) schemes is undertaken through offline comparisons and through application in the Canadian Centre for Climate Modelling and Analysis (CCCma) fourth-generation atmospheric general circulation model (AGCM4). In general, each scheme requires different input quantities to determine the OSA. Common to all schemes is a dependence on the solar zenith angle (SZA). A direct comparison of the SZA dependence of the schemes reveals significant differences in the predicted albedos. Other input quantities include wind speed and aerosol/cloud optical depth, which are also analyzed.

An offline one-dimensional radiative transfer model is used to quantitatively study the impact of ocean surface albedo on the radiative transfer process. It is found that, as a function of SZA and wind speed, the difference in reflected solar flux at the top of the atmosphere is in general agreement between OSA schemes that depend on these quantities, with a difference <10 W m−2. However, for simpler schemes that depend only on SZA the difference in this flux can approach 10–20 W m−2.

The impact of the different OSA schemes is assessed through multiyear simulations of present-day climate in AGCM4. Five-year means of the reflected clear-sky flux at the top of the atmosphere reveal local differences of up to several watts per meters squared between any of the schemes. Globally, all schemes display a similar negative bias relative to the Earth Radiation Budget Experiment (ERBE) observations. This negative bias is largely reduced by comparison with the recently released Clouds and the Earth’s Radiant Energy System (CERES) data. It is shown that the local upward clear-sky flux at the surface is more sensitive to the OSA formulation than the clear-sky upward flux at the top of atmosphere. It is found that the global energy balance of the model at the top of the atmosphere and at the surface is surprisingly insensitive to which OSA scheme is employed.
The Southern Hemisphere Westerlies in a Warming World: Propping Open the Door to the Deep Ocean
Authors: Russell Joellen L. , Dixon Keith W. , Gnanadesikan Anand , Stouffer Ronald J. , Toggweiler J. R.
Published: December 2006

A coupled climate model with poleward-intensified westerly winds simulates significantly higher storage of heat and anthropogenic carbon dioxide by the Southern Ocean in the future when compared with the storage in a model with initially weaker, equatorward-biased westerlies. This difference results from the larger outcrop area of the dense waters around Antarctica and more vigorous divergence, which remains robust even as rising atmospheric greenhouse gas levels induce warming that reduces the density of surface waters in the Southern Ocean. These results imply that the impact of warming on the stratification of the global ocean may be reduced by the poleward intensification of the westerlies, allowing the ocean to remove additional heat and anthropogenic carbon dioxide from the atmosphere.
On the Relationship between Stratiform Low Cloud Cover and Lower-Tropospheric Stability
Authors: Wood Robert , Bretherton Christopher S.
Published: December 2006

Observations in subtropical regions show that stratiform low cloud cover is well correlated with the lower-troposphere stability (LTS), defined as the difference in potential temperature θ between the 700-hPa level and the surface. The LTS can be regarded as a measure of the strength of the inversion that caps the planetary boundary layer (PBL). A stronger inversion is more effective at trapping moisture within the marine boundary layer (MBL), permitting greater cloud cover. This paper presents a new formulation, called the estimated inversion strength (EIS), to estimate the strength of the PBL inversion given the temperatures at 700 hPa and at the surface. The EIS accounts for the general observation that the free-tropospheric temperature profile is often close to a moist adiabat and its lapse rate is strongly temperature dependent. Therefore, for a given LTS, the EIS is greater at colder temperatures. It is demonstrated that while the seasonal cycles of LTS and low cloud cover fraction (CF) are strongly correlated in many regions, no single relationship between LTS and CF can be found that encompasses the wide range of temperatures occurring in the Tropics, subtropics, and midlatitudes. However, a single linear relationship between CF and EIS explains 83% of the regional/seasonal variance in stratus cloud amount, suggesting that EIS is a more regime-independent predictor of stratus cloud amount than is LTS under a wide range of climatological conditions.

The result has some potentially important implications for how low clouds might behave in a changed climate. In contrast to Miller’s thermostat hypothesis that a reduction in the lapse rate (Clausius–Clapeyron) will lead to increased LTS and increased tropical low cloud cover in a warmer climate, the results here suggest that low clouds may be much less sensitive to changes in the temperature profile if the vertical profile of tropospheric warming follows a moist adiabat.
The Use of Field Experiments for Studies of Employment Discrimination: Contributions, Critiques, and Directions for the Future
Authors: Pager Devah
Published: December 2006

Have we conquered the problems of racial discrimination? Or have acts of discrimination become too subtle and covert for detection? This discussion serves to situate current debates about discrimination within the context of available measurement techniques. In this article, the author (1) considers the arguments from recent debates over the contemporary relevance of labor market discrimination; (2) provides a detailed introduction to experimental field methods for studying discrimination (also called audit studies), including an overview of the findings of recent audit studies of employment; (3) addresses the primary critiques of the audit methodology and the potential threats to the validity of studies of this kind; and (4) considers how we might reconcile evidence from field experiments with those from analyses of large-scale survey data, each of which points to markedly different conclusions. Only by gathering rigorous empirical evidence can we begin to understand the nature of race and racial discrimination in labor markets today.
Demobilization of the Individualistic Bias: Housing Market Discrimination as a Contributor to Labor Market and Economic Inequality
Authors: Squires Gregory D.
Published: December 2006

Racial discrimination in the nation's housing markets and patterns of residential segregation have contributed to labor market inequalities and economic disparities generally. Housing values are suppressed in minority communities, undercutting wealth accumulation by nonwhite families. Job growth in suburban communities coupled with the concentration of public housing in central city communities restricts minority access to jobs. A range of institutionalized practices by housing providers and public policies by government agencies at all levels have nurtured and exacerbated racial inequalities grounded in traditional stereotypes. But a number of policy options are available to ameliorate these inequities. Eschewing individualistic explanations of racial inequality that point to personal deficiencies and cultural characteristics of minority communities, these policy recommendations—premised on a structural perspective—offer promise for reducing racial inequities in housing and related economic disparities.
Family Background, Race, and Labor Market Inequality
Authors: Conley Dalton , Glauber Rebecca
Published: December 2006

For decades, social scientists have relied on sibling correlations as indicative of the effect of “global family background” on socioeconomic status. This study advances this line of inquiry by drawing on data from the Panel Study of Income Dynamics to analyze racial differences in siblings' labor market and socioeconomic outcomes. We find that African Americans have lower sibling correlations in labor market earnings and family income than whites. Across the life course, African American siblings move toward greater resemblance than whites. These findings suggest that the effect of family background on socioeconomic outcomes is weaker for African Americans than for whites. Volatility in earlier career stages may suppress the effect of family background on labor market outcomes, and this dynamic is especially pronounced for African Americans who lack resources to insulate themselves from volatile events.
Black Under-representation in Management across U.S. Labor Markets
Authors: Cohen Philip N. , Huffman Matt L.
Published: December 2006

Although many researchers have documented higher levels of black-white inequality in areas with a high concentration of blacks, the mechanisms underlying this finding have been elusive. Black underrepresentation in management may be one such mechanism. We ask whether black workers' underrepresentation in managerial jobs is especially pronounced in labor markets with a larger black population. Using a unique, two-level data set that combines a large data set of private sector firms with Census data on local labor markets, the authors' hierarchical logistic models strongly support this hypothesis. Net of establishment and labor market-level controls, the likelihood that an establishment exhibits a significant underrepresentation of blacks in management is substantially increased when it operates in a high-proportion black labor market context.
Effects of Distraction on Pain, Fear, and Distress During Venous Port Access and Venipuncture in Children and Adolescents With Cancer
Authors: Windich-Biermeier Andrea , Sjoberg Isabelle , Dale Juanita Conkin , Eshelman Debra , Guzzetta Cathie E.
Published: December 2006

This study evaluates the effect of self-selected distracters (ie, bubbles, I Spy: Super Challenger book, music table, virtual reality glasses, or handheld video games) on pain, fear, and distress in 50 children and adolescents with cancer, ages 5 to 18, with port access or venipuncture. Using an intervention-comparison group design, participants were randomized to the comparison group (n = 28) to receive standard care or intervention group (n = 22) to receive distraction plus standard care. All participants rated their pain and fear, parents rated participant fear, and the nurse rated participant fear and distress at 3 points in time: before, during, and after port access or venipuncture. Results show that self-reported pain and fear were significantly correlated (P = .01) within treatment groups but not significantly different between groups. Intervention participants demonstrated significantly less fear (P <.001) and distress (P = .03) as rated by the nurse and approached significantly less fear (P = .07) as rated by the parent. All intervention parents said the needlestick was better because of the distracter. The authors conclude that distraction has the potential to reduce fear and distress during port access and venipuncture.
The Use of Herbal Therapies in Pediatric Oncology Patients: Treating Symptoms of Cancer and Side Effects of Standard Therapies
Authors: Quimby Erin L.
Published: December 2006

Complementary and alternative medicine is increasing in use in the pediatric oncology population. Although there is a multitude of herbal therapies used, the focus of this article is a review of the literature addressing some herbal therapies used to treat the symptoms of cancer and side effects of traditional methods of treatment. Ginger is used in the treatment of nausea and vomiting. St. John's wort is successful in treating depression and anxiety. Echinacea is used as an immunostimulant. Herbal therapies in the pediatric oncology population are usually initiated and managed by parents. Many herbal therapies are beneficial, but some potential herb-drug interactions should be considered. This poses a challenge to the oncology nurse because herbal treatments are managed by the parents and pharmaceuticals are managed by the practitioner. Educating the patient, family, and practitioner is important in ensuring a thorough health history assessment and, subsequently, safe and effective herbal and pharmacological therapies.
Efficiency and Revenue Issues in the Jamaican External Trade Sector
Authors: Maskus Keith E. , Rioja Felix K.
Published: December 2006

This article is concerned with issues of the efficiency and revenue aspects of the current Jamaican taxes on trade, including tariffs, other charges, and customs valuation questions. It also considers revenue implications of further Jamaican tariff liberalization through the World Trade Organization as a member of the Caribbean Community and through the proposed Free Trade Agreement of the Americas. Finally, it comments on the scope for integrating tariff reform with reforms in domestic taxes to recoup potential revenue losses and increase the efficiency of the tax system.
Are Jamaica’s Direct Taxes on Labor “Fair”?
Authors: Alm James , Wallace Sally
Published: December 2006

The Government of Jamaica imposes a variety of taxes on the earnings of labor. Jamaica’s direct taxes and charges on labor income include the pay-asyou-earn (PAYE) income tax and five payroll taxes. In total, these taxes generate nearly one-third of the total tax revenues of the government in fiscal year 2002-2003, with the PAYE itself responsible for more than one-fifth of total revenues. This article uses unique micro-level data to analyze the vertical and, especially, the horizontal equity of these taxes. The authors find that the taxes are generally progressive in their overall pattern of incidence but that they also introduce significant horizontal inequities due to their uneven coverage and their many special provisions.
Should Jamaica Tax Corporate Income?
Authors: Rider Mark
Published: December 2006

This article evaluates Jamaica’s corporate income tax and tax incentive schemes. There are considerable administrative burdens and economic distortions associated with Jamaica’s income tax regime that result from taxing capital income in a “small open economy.” These burdens make a strong argument for repealing Jamaica’s corporate income tax. However, this tax is an important source of government revenue, and the political realities are such that repeal may not be a viable option. That being the case, Jamaica may have little choice but to try to broaden the tax base by trimming back on the tax incentive regime, committing the resources needed to improve enforcement of the corporate income tax, and lowering the tax rate in a revenue neutral manner. This approach would have the advantage of preserving an important source of tax revenue, staunching the erosion of the personal income tax base due to income shifting, and reducing the complexity and economic distortions associated with the current tax structure.
Comprehensive Tax Reform in Jamaica
Authors: Bahl Roy , Wallace Sally
Published: December 2006

When the fiscal situation of a country gets too far out of control, government will often call for a comprehensive review of the tax system to try to get back on a sustainable path. Jamaica is just such a case. The Government of Jamaica called in 2005 for a tax reform to address the fiscal problems. The articles in this special issue of Public Finance Review, and this overview, describe the analytic work that was undertaken to support Jamaica’s comprehensive tax reform efforts. The contributions here are in the approach taken, in the analytic work, and in the lessons from these efforts.
Diagnostic value of serum precipitins to mould antigens in active hypersensitivity pneumonitis
Authors: Fenoglio C-M. , Reboux G. , Sudre B. , Mercier M. , Roussel S. , Cordier J-F. , Piarroux R. , Dalphin J-C.
Published: December 2006

Serum precipitins have a controversial diagnostic value in hypersensitivity pneumonitis (HP). The present authors’ objective was to assess their diagnostic value by developing scores from a panel of specific antigens tested by two techniques (electrosyneresis and double diffusion) to discriminate active HP from other interstitial lung diseases.

Consecutive patients presenting with a condition for which HP was considered in the differential diagnosis were included in the study. All patients underwent the same standardised diagnostic procedure, including precipitin tests performed in routine conditions. Clinical manifestations, bronchoalveolar lavage and high-resolution computed tomography defined the presence or absence of HP. Receiver-operating characteristic curves and logistic regression were used to develop the serological scores.

A total of 122 patients (including 31 cases of HP) were included in the study. Five antigens from the panel were selected for the serological scores (Absidia corymbifera, Eurotium amstelodami, Wallemia sebi, Saccharopolyspora rectivirgulaand mesophilicStreptomycessp.). Electrosyneresis was more discriminative than the double-diffusion technique. Predictive negative values varied 81–88% and predictive positive values varied 71–75% for prevalence of HP 20–35%.

In conclusion, serological scores using a panel of relevant antigens may guide both biological and clinical practice in areas of high prevalence of hypersensitivity pneumonitis.
Mitochondrial dysfunction in COPD patients with low body mass index
Authors: Rabinovich R. A. , Bastos R. , Ardite E. , Llinàs L. , Orozco-Levi M. , Gea J. , Vilaró J. , Barberà J. A. , Rodríguez-Roisin R. , Fernández-Checa J. C. , Roca J.
Published: December 2006

Patients with chronic obstructive pulmonary disease (COPD) show abnormal adaptations of skeletal muscle redox status after exercise training. Increased skeletal muscle oxidative stress in COPD patients may prompt mitochondrial dysfunction.

The present study explores the association between body composition and mitochondrial respiration in seven COPD patients with low body mass index (BMIL), eight COPD patients with normal body mass index (BMIN) and seven healthy controls. All of them underwent avastus lateralisbiopsy in which muscle structure,in vitromitochondrial respiratory function, uncoupling protein 3 (UCP3) mRNA expression and glutathione levels in both isolated mitochondria and the whole muscle were determined.

Mitochondrial respiratory function (assessed by acceptor control ratio (ACR)) was impaired in BMIL(2.2±0.6) compared with both BMIN(5.3±1.3) and controls (8.2±1.3). ACR significantly correlated with arterial oxygen tensionand with muscle endurance but it showed a negative association with exercise-induced increase in blood lactate levels. UCP3 mRNA expression was reduced in BMILpatients.

In conclusion, chronic obstructive pulmonary disease patients with low body mass index show electron transport chain dysfunction, which may contribute to low muscle endurance in the current subgroup of patients.
Fractalkine-induced smooth muscle cell proliferation in pulmonary hypertension
Authors: Perros F. , Dorfmüller P. , Souza R. , Durand-Gasselin I. , Godot V. , Capel F. , Adnot S. , Eddahibi S. , Mazmanian M. , Fadel E. , Hervé P. , Simonneau G. , Emilie D. , Humbert M.
Published: December 2006

Pulmonary hypertension is characterised by a progressive increase in pulmonary arterial resistance due to endothelial and smooth muscle cell proliferation resulting in chronic obstruction of small pulmonary arteries. There is evidence that inflammatory mechanisms may contribute to the pathogenesis of human and experimental pulmonary hypertension.

The aim of the study was to address the role of fractalkine (CX3CL1) in the inflammatory responses and pulmonary vascular remodelling of a monocrotaline-induced pulmonary hypertension model.

The expression of CX3CL1 and its receptor CX3CR1 was studied in monocrotaline-induced pulmonary hypertension by means of immunohistochemistry and quantitative reverse-transcription PCR on laser-captured microdissected pulmonary arteries.

It was demonstrated that CX3CL1 was expressed by inflammatory cells surrounding pulmonary arterial lesions and that smooth muscle cells from these vessels had increased CX3CR1 expression. It was then shown that cultured rat pulmonary artery smooth muscle cells expressed CX3CR1 and that CX3CL1 induced proliferation but not migration of these cells.

In conclusion, the current authors proposed that fractalkine may act as a growth factor for pulmonary artery smooth muscle cells. Chemokines may thus play a role in pulmonary artery remodelling.
Long-term follow-up of thoracoscopic talc pleurodesis for primary spontaneous pneumothorax
Authors: Györik S. , Erni S. , Studler U. , Hodek-Wuerz R. , Tamm M. , Chhajed P. N.
Published: December 2006

The aim of the present study was to evaluate the long-term outcome of patients with primary spontaneous pneumothorax treated with talc pleurodesis.

A follow-up study was undertaken in all patients with primary spontaneous pneumothorax who underwent talc pleurodesis for prolonged air leak or recurrence using thoracoscopy.

In total, 112 patients underwent pleurodesis and follow-up data was obtained in 63 (56%) patients: 45 patients were available for clinical follow-up, 14 for telephone follow-up and four were dead. The causes of death were unrelated to the pleurodesis. There were no episodes of acute respiratory failure following pleurodesis. A total of 56 (95%) out of the cohort of 59 patients had a successful pleurodesis. Surgical pleurectomy was required in three (5%) patients for persistent air leak. Median duration of follow-up after talc pleurodesis was 118 months. Long-term success was observed in 53 (95%) out of 56 patients. Recurrent pneumothorax was observed in three (5%) out of 56 patients. Patients with successful talc pleurodesis had a median forced vital capacity (FVC) of 102% and median total lung capacity of 99% at follow-up. Comparing smokers and nonsmokers, the forced expiratory volume in one second (FEV1) was significantly lower in smokers and there was a tendency for the FEV1/FVC ratio to be lower in smokers.

Talc pleurodesis in patients with primary spontaneous pneumothoraxviathoracoscopy is an effective procedure associated with normal lung function in patients who do not smoke.