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The hot Jupiter HD 209458b is particularly amenable to detailed study as it is among the brightest transiting exoplanet systems currently known (V-mag = 7.65; K-mag = 6.308) and has a large planet-to-star contrast ratio. HD 209458b is predicted to be in synchronous rotation about its host star with a hot spot that is shifted eastward of the substellar point by superrotating equatorial winds. Here we present the first full-orbit observations of HD 209458b, in which its 4.5 μm emission was recorded with Spitzer/IRAC. Our study revises the previous 4.5 μm measurement of HD 209458b's secondary eclipse emission downward by 35% to , changing our interpretation of the properties of its dayside atmosphere. We find that the hot spot on the planet's dayside is shifted eastward of the substellar point by 40.°9 ± 6.°0, in agreement with circulation models predicting equatorial superrotation. HD 209458b's dayside (T bright = 1499 ± 15 K) and nightside (T bright = 972 ± 44 K) emission indicate a day-to-night brightness temperature contrast smaller than that observed for more highly irradiated exoplanets, suggesting that the day-to-night temperature contrast may be partially a function of the incident stellar radiation. The observed phase curve shape deviates modestly from global circulation model predictions potentially due to disequilibrium chemistry or deficiencies in the current hot CH4 line lists used in these models. Observations of the phase curve at additional wavelengths are needed in order to determine the possible presence and spatial extent of a dayside temperature inversion, as well as to improve our overall understanding of this planet's atmospheric circulation. © 2014. The American Astronomical Society. All rights reserved..

PROBLEM: Although two of the primary risk factors for being bullied include “male” and “middle school” status, a gap in knowledge exists of middle school boys' personal accounts and meanings of being bullied and their healing. METHODS: Giorgi's descriptive phenomenological approach using open-ended semi-structured individual interviews was used to collect and analyze evidence related to middle school boys' lived experiences of being bullied and healing. Roger's Science of Unitary Human Beings (SUHB) guided interpretation of the healing patterns. FINDINGS: Three patterns of healing were identified in boys' experiences: meaning-making, self-transcendence, and nonviolently claiming personal power. CONCLUSIONS: Evidence of healing patterns exists in middle school boys' experiences of being bullied, offering a foundation for further research and practice focused on healing. When working with middle school boys who have been bullied, nurses need to ask about their experiences and promote their healing. [ABSTRACT FROM AUTHOR]

Since the early 1990s, evidence-based practice has gained momentum, but barriers persist between knowledge development and application in practice. The Massachusetts General Hospital reengineered the Nursing Research Committee as one vehicle for promoting research-based practice. Using the Promoting Action on Research Implementation in Health Services framework, the mission and methods (context) to advance research-based practice are explicated. Characteristics of the membership, leadership, and practice environment that facilitate research utilization are delineated. [ABSTRACT FROM AUTHOR]

Background: Limited data exist examining whether timing and/or duration of eating behaviors throughout the day affect sleep health., Objective: The aim of this study was to identify the relationship between eating behaviors and sleep in young adults without chronic diseases or conditions., Design: This was a cross-sectional study using 7 days of baseline data from a randomized crossover trial., Participants/setting: Participants included 52 young adults. The study took place in West Lafayette, Indiana, between April 2017 and May 2018., Main Outcome Measures: Timing and duration of eating were assessed via 3 nonconsecutive, 24-hour dietary recalls. Bedtime, wake time, total sleep time, sleep latency, sleep efficiency, and wake after sleep onset were measured over 7 days via wrist actigraphy and sleep diaries., Statistical Analyses Performed: Two-way analyses of variance were applied to assess group differences based on timing of consumption (early vs late eating) and duration of eating (long: >13 hours, short: <11 hours, or standard: 11-13 hours) with post-hoc pairwise comparisons., Results: Main effects of timing of consumption, but not duration of eating, were detected for wake time, bedtime, and sleep efficiency (all, P < .05). Specifically, participants with later eating patterns that included breakfast skipping had later wake times and later bedtimes than those with earlier eating patterns. In addition, those who had later eating patterns that included breakfast skipping and nighttime eating experienced lower sleep efficiency (mean [SE], 77.0% [2.3%]) vs those who consumed breakfast and no nighttime eating (mean [SE], 84.6% [1.4%]; P < .001) and those who skipped breakfast but had no nighttime eating (mean [SE], 84.2% [2.5]; P < .05). Those who consumed breakfast but also had nighttime eating had a mean (SE) sleep efficiency of 82.4% (1.4%) (P = .09)., Conclusions: The timing of eating was associated with sleep-wake onset and sleep efficiency. This study provides the preliminary characterization of eating behaviors relative to sleep-wake cycles and highlights the need for experimental studies to understand whether manipulating the timing of eating occasions to better align with sleep-wake cycles could improve sleep health., (Published by Elsevier Inc.)

Aim: To investigate the self-reported levels of social support from friends and family and from nurses as mediators of the relationship between self-rated physical and psychological condition in hospitalised patients., Design: Cross-sectional study of adult inpatients at a large tertiary-care hospital in the northeast United States., Methods: Multiple mediation analysis of survey data., Results: In surveys received from 324 inpatients, one fourth of the variation in patients' self-rated psychological condition was explained by self-rated physical condition. Social support from family and friends mediated a significant proportion (11.0%) of the relationship between self-rated physical and psychological condition, however social support from nurses did not., Conclusion: Social support from family and friends can positively influence the psychological health of inpatients, but nurses are not an adequate replacement for the social support provided by family and friends., Implications for Nursing: Although nurses cannot replace the social support provided by family and friends, the assessment of social isolation and care planning of interventions to support patients is a fundamental nursing role. Technology to connect patients with friends and family should be used to mitigate isolation for hospitalised patients unable to receive in-person visits from loved ones., Impact: The influence of social support from family and friends and nurses was addressed. The study found social support from family and friends, but not nurses, to influence the relationship between physical and psychological ratings. This finding has implications for the role of nurses in the hospital setting., Reporting Method: Strengthening the Reporting of Observational Studies in Epidemiology guidelines were followed., (© 2023 John Wiley & Sons Ltd.)

Polycyclic aromatic sulfur heterocycles are environmental pollutants formed from incomplete combustion processes and crude oil spills. Their excited state dynamics are not understood. Herein, femtosecond transient absorption is combined with steady-state spectroscopy and computational methods to elucidate the relaxation mechanisms of three dibenzothiophene derivatives. The low-energy singlet and triplet states all have ππ* character in the Franck-Condon region, and two minima were located in the S 1 surface. Excitation at 320 nm populates their S 1 state directly, which relaxes with lifetimes ranging from 4 to 13 ps. Most of the S 1 population undergoes efficient intersystem crossing to the triplet state with lifetimes ranging from 820 ± 50 to 900 ± 30 ps. The compounds exhibit negligible nonradiative internal conversion, low fluorescence yields of 1.2 to 1.6%, and triplet yields of ca. 98%. Linear interpolation of internal coordinates reveals the chemical basis for relaxing the spin-forbidden intersystem crossing in these π-aromatic systems.

Background: Clinical Research Nurses practice across a wide spectrum of roles and settings within the global research enterprise. Clinical Research Nurses working with clinical trials face a dual fidelity in their role, balancing integrity of the protocol and quality care for participants., Aims: The purpose of this study was to describe Clinical Research Nurses' experiences in clinical trials, educational preparation, and career pathways, to gain a deeper understanding of clinical research nursing contributions to the clinical research enterprise., Methods: An internet-based survey was conducted to collect demographic data and free text responses to four open-ended queries related to the experience of nurses working in clinical trials research, educational preparation, and role pathways. Qualitative content analysis was used to analyze free text responses. The study was guided by the Clinical Research Nursing Domain of Practice and Duffy's Quality Caring Model of relationship centered professional encounters., Results: Forty clinical research nurses responded to the open-ended questions with themes related to dual fidelity to study participants and protocols, relationships and nursing care, interdisciplinary team membership and contributing to science, emerging from the data. Gaps in educational preparation and professional pathways were identified., Conclusion: This study provides insights to unique clinical research nurse practice contributions in the clinical trial research enterprise within a context of Duffy's Quality Caring Model., Competing Interests: Declaration of conflicting interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2022.)

Background:: Clinical investigation is a growing field employing increasing numbers of nurses. This has created a new specialty practice defined by aspects unique to nursing in a clinical research context: the objectives (to implement research protocols and advance science), setting (research facilities), and nature of the nurse-participant relationship. The clinical research nurse role may give rise to feelings of ethical conflict between aspects of protocol implementation and the duty of patient advocacy, a primary nursing responsibility. Little is known about whether research nurses experience unique ethical challenges distinct from those experienced by nurses in traditional patient-care settings., Research Objectives:: The purpose of the study was to describe the nature of ethical challenges experienced by clinical research nurses within the context of their practice., Research Design:: The study utilized a qualitative descriptive design with individual interviews., Participants and Research Context:: Participating nurses (N = 12) self-identified as having experienced ethical challenges during screening. The majority were Caucasian (90%), female (83%), and worked in outpatient settings (67%). Approximately 50% had > 10 years of research experience., Ethical Considerations:: The human subjects review board approved the study. Written informed consent was obtained., Findings:: Predominant themes were revealed: (1) the inability to provide a probable good, or/do no harm, and (2) dual obligations (identity as a nurse vs a research nurse). The following patterns and subthemes emerged: conflicted allegiances between protocol implementation, needs of the participant, desire to advance science, and tension between the nurse-patient therapeutic relationship versus the research relationship., Discussion:: Participants described ethical challenges specific to the research role. The issues are central to the nurse-participant relationship, patient advocacy, the nurse's role in implementing protocols, and/or advancing science., Conclusion:: Ethical challenges related to the specialized role of clinical research nurses were identified. More research is warranted to fully understand their nature and frequency and to identify support systems for resolution.

Infrared transmission and emission spectroscopy of exoplanets, recorded from primary transit and secondary eclipse measurements, indicate the presence of the most abundant carbon and oxygen molecular species (H2O, CH4, CO and CO2) in a few exoplanets. However, efforts to constrain the molecular abundances to within several orders of magnitude are thwarted by the broad range of degenerate solutions that fit the data. Here, we explore, with radiative transfer models and analytical approximations, the nature of the degenerate solution sets resulting from the sparse measurements of 'hot Jupiter' exoplanets. As demonstrated with simple analytical expressions, primary transit measurements probe roughly four atmospheric scale heights at each wavelength band. Derived mixing ratios from these data are highly sensitive to errors in the radius of the planet at a reference pressure. For example, an uncertainty of 1% in the radius of a 1000 K and H2-based exoplanet with Jupiter's radius and mass causes an uncertainty of a factor of approximately 100-10,000 in the derived gas mixing ratios. The degree of sensitivity depends on how the line strength increases with the optical depth (i.e. the curve of growth) and the atmospheric scale height. Temperature degeneracies in the solutions of the primary transit data, which manifest their effects through the scale height and absorption coefficients, are smaller. We argue that these challenges can be partially surmounted by a combination of selected wavelength sampling of optical and infrared measurements and, when possible, the joint analysis of transit and secondary eclipse data of exoplanets. However, additional work is needed to constrain other effects, such as those owing to planetary clouds and star spots. Given the current range of open questions in the field, both observations and theory, there is a need for detailed measurements with space-based large mirror platforms (e.g. James web space telescope) and smaller broad survey telescopes as well as ground-based efforts.

Objective: To describe a case of status epilepticus believed to be a consequence of inadvertent intrathecal administration of cefazolin in a dog undergoing a myelogram., Case Summary: A 4-year-old, 6.5 kg, male neutered Dachshund was referred for evaluation of an acute onset hind limb paraparesis. While performing a lumbar myelogram, cefazolin was inadvertently injected into the ventral subarachnoid space. Subsequent refractory seizure activity was attributed to the epileptogenic effects of intrathecally administered cefazolin. Supportive therapy led to eventual complete recovery., New or Unique Information Provided: Although epileptogenic effects of intrathecally administered cefazolin are well documented in the human and experimental animal model literature, to the authors' knowledge this has not been characterized in the veterinary literature. This case highlights the need to be diligent and mindful when one administers medications, and describes the management of a dog adversely affected as a consequence of a medical error., (© Veterinary Emergency and Critical Care Society 2013.)

Visible light irradiation of a ruthenium(II) quinone-containing complex, [(phen)(2)Ru(phendione)](2+) (1(2+)), where phendione = 1,10-phenanthroline-5,6-dione, leads to DNA cleavage in an oxygen independent manner. A combination of NMR analyses, transient absorption spectroscopy, and fluorescence measurements in water and acetonitrile reveal that complex 1(2+) must be hydrated at the quinone functionality, giving [(phen)(2)Ru(phenH(2)O)](2+) (1H(2)O(2+), where phenH(2)O = 1,10-phenanthroline-6-one-5-diol), in order to access a long-lived (3)MLCT(hydrate) state (τ ∼ 360 ns in H(2)O) which is responsible for DNA cleavage. In effect, hydration at one of the carbonyl functions effectively eliminates the low-energy (3)MLCT(SQ) state (Ru(III) phen-semiquinone radical anion) as the predominant nonradiative decay pathway. This (3)MLCT(SQ) state is very short-lived (<1 ns) as expected from the energy gap law for nonradiative decay, (1) and too short-lived to be the photoactive species. The resulting excited state in 1H(2)O(2+)* has photophysical properties similar to the (3)MLCT state in [Ru(phen)(3)](2+)* with the added functionality of basic sites at the ligand periphery. Whereas [Ru(phen)(3)](2+)* does not show direct DNA cleavage, the deprotonated form of 1H(2)O(2+)* does via a proton-coupled electron transfer (PCET) mechanism where the peripheral basic oxygen sites act as the proton acceptor. Analysis of the small molecule byproducts of DNA scission supports the conclusion that cleavage occurs via H-atom abstraction from the sugar moieties, consistent with a PCET mechanism. Complex 1(2+) is a rare example of a ruthenium complex which 'turns on' both reactivity and luminescence upon switching to a hydrated state.

This paper shares the experience of establishing a research nurse forum aimed at knowledge sharing, problem solving, and community building from the perspective of a group of clinical research nurses at Massachusetts General Hospital (MGH), a tertiary care center in Boston, -Massachusetts. We report on a sequence of developmental steps taken to create this forum as an example of best practice for research nurses. Logistical considerations, mission and goals, as well as outcomes and implications for practice are described, with the intent that others interested in building similar forums can replicate aspects of this model within their own practice settings., (© 2012 Wiley Periodicals, Inc.)

Exoplanets--planets orbiting around stars other than our own Sun--appear to be common. Significant research effort is now focused on the observation and characterization of exoplanet atmospheres. Species such as water vapour, methane, carbon monoxide and carbon dioxide have been observed in a handful of hot, giant, gaseous planets, but cooler, smaller planets such as Gliese 1214b are now analysable with current telescopes. Water is the key chemical dictating habitability. The current observations of water in exoplanets from both space and the ground are reviewed. Controversies surrounding the interpretation of these observations are discussed. Detailed consideration of available radiative transfer models and linelists are used to analyse these differences in interpretation. Models suggest that there is a clear need for data on the pressure broadening of water transitions by H(2) at high temperatures. The reported detections of water appear to be robust, although final confirmation will have to await the better quality observational data provided by currently planned dedicated space missions.

Titan has clouds, rain and lakes--like Earth--but composed of methane rather than water. Unlike Earth, most of the condensable methane (the equivalent of 5 m depth globally averaged) lies in the atmosphere. Liquid detected on the surface (about 2 m deep) has been found by radar images only poleward of 50° latitude, while dune fields pervade the tropics. General circulation models explain this dichotomy, predicting that methane efficiently migrates to the poles from these lower latitudes. Here we report an analysis of near-infrared spectral images of the region between 20° N and 20° S latitude. The data reveal that the lowest fluxes in seven wavelength bands that probe Titan's surface occur in an oval region of about 60 × 40 km(2), which has been observed repeatedly since 2004. Radiative transfer analyses demonstrate that the resulting spectrum is consistent with a black surface, indicative of liquid methane on the surface. Enduring low-latitude lakes are best explained as supplied by subterranean sources (within the last 10,000 years), which may be responsible for Titan's methane, the continual photochemical depletion of which furnishes Titan's organic chemistry.

Detection of molecules using infrared spectroscopy probes the conditions and compositions of exoplanet atmospheres. Water (H(2)O), methane (CH(4)), carbon dioxide (CO(2)), and carbon monoxide (CO) have been detected in two hot Jupiters. These previous results relied on space-based telescopes that do not provide spectroscopic capability in the 2.4-5.2 microm spectral region. Here we report ground-based observations of the dayside emission spectrum for HD 189733b between 2.0-2.4 microm and 3.1-4.1 microm, where we find a bright emission feature. Where overlap with space-based instruments exists, our results are in excellent agreement with previous measurements. A feature at approximately 3.25 microm is unexpected and difficult to explain with models that assume local thermodynamic equilibrium (LTE) conditions at the 1 bar to 1 x 10(-6) bar pressures typically sampled by infrared measurements. The most likely explanation for this feature is that it arises from non-LTE emission from CH(4), similar to what is seen in the atmospheres of planets in our own Solar System. These results suggest that non-LTE effects may need to be considered when interpreting measurements of strongly irradiated exoplanets.

Background: Current gold standard markers for myocardial damage are troponins I and T, which are both sensitive and specific for the detection of myocardial infarction, but require up to 6 h to become reliably elevated in serum. Investigation into markers with potential to identify patients with early ischaemic changes is therefore intense. Choline is reported to be prognostic in patients presenting with acute coronary syndromes via its release from ischaemic cell membranes., Methods: Liquid chromatography tandem mass spectrometry was used to develop a method to quantitate choline in plasma and blood. The method involves addition of a deuterated internal standard to an aliquot of plasma or blood followed by organic solvent addition, which precipitates the proteins in the sample. Preparation was carried out directly into a 96-deep-well plate. Chromatography of choline used a strong cation exchange column and separation used a Waters Atlantis dC18 analytical column positioned directly before the mass spectrometer source, allowing on-line preanalytical clean up of the sample., Results: The lower limit of quantitation was 0.38 micromol/L, linearity was observed up to 754 micromol/L, with a working concentration range of 0.38-224 micromol/L, inter- and intra-assay coefficients of variation were <6% and <4%, respectively. Samples were stable throughout five freeze-thaw cycles and recovery was between 94% and 114%., Conclusions: The assay was successfully validated in accordance with FDA guidelines and is suitable for quantitation of choline in research and clinical settings.

Almost 500 extrasolar planets have been found since the discovery of 51 Peg b by Mayor and Queloz in 1995. The traditional field of planetology has thus expanded its frontiers to include planetary environments not represented in our Solar System. We expect that in the next five years space missions (Corot, Kepler and GAIA) or ground-based detection techniques will both increase exponentially the number of new planets discovered and lower the present limit of a approximately 1.9 Earth-mass object [e.g. Mayor et al., Astron. Astrophys., 2009, 507, 487]. While the search for an Earth-twin orbiting a Sun-twin has been one of the major goals pursued by the exoplanet community in the past years, the possibility of sounding the atmospheric composition and structure of an increasing sample of exoplanets with current telescopes has opened new opportunities, unthinkable just a few years ago. As a result, it is possible now not only to determine the orbital characteristics of the new bodies, but moreover to study the exotic environments that lie tens of parsecs away from us. The analysis of the starlight not intercepted by the thin atmospheric limb of its planetary companion (transit spectroscopy), or of the light emitted/reflected by the exoplanet itself, will guide our understanding of the atmospheres and the surfaces of these extrasolar worlds in the next few years. Preliminary results obtained by interpreting current atmospheric observations of transiting gas giants and Neptunes are presented. While the full characterisation of an Earth-twin might requires a technological leap, our understanding of large terrestrial planets (so called super-Earths) orbiting bright, later-type stars is within reach by current space and ground telescopes.

Objectives: Choline has been identified as a promising marker of coronary inflammation, plaque destabilisation and ischaemia. We sought to evaluate plasma choline levels for rapid confirmation or exclusion of acute myocardial infarction (AMI) in the Emergency Department (ED) and for predicting major adverse cardiac events (MACE)., Methods: We prospectively recruited 361 patients who presented to the ED with suspected cardiac chest pain within the previous 24 h. Blood was drawn at the time of presentation for plasma choline levels. All patients underwent troponin T testing > or = 12 h after symptom onset and were followed up for the occurrence of MACE within 6 months. Whole blood choline (WBCho) levels were also measured in a convenience sample of 39 patients., Results: Plasma choline levels did not help to predict a diagnosis of AMI (odds ratio (OR) 1.00 (95% confidence intervals (CI) 0.91-1.10, p = 0.98). For a diagnosis of AMI the area under the receiver operating characteristic (ROC) curve was 0.48. Plasma choline was not predictive of the combined endpoint of MACE (OR 1.03, 95% CI 0.95-1.12, p = 0.45) but predicted AMI within 6 months (OR 1.31, 95% CI 1.09-1.56, p = 0.003). WBCho levels were significantly different to plasma levels and were predictive of MACE., Conclusions: Plasma choline, measured at the time of ED presentation, is not a diagnostic marker of AMI but predicts AMI within 6 months. While plasma choline failed to predict MACE, WBCho was predictive and warrants further evaluation.

Clouds on Titan result from the condensation of methane and ethane and, as on other planets, are primarily structured by circulation of the atmosphere. At present, cloud activity mainly occurs in the southern (summer) hemisphere, arising near the pole and at mid-latitudes from cumulus updrafts triggered by surface heating and/or local methane sources, and at the north (winter) pole, resulting from the subsidence and condensation of ethane-rich air into the colder troposphere. General circulation models predict that this distribution should change with the seasons on a 15-year timescale, and that clouds should develop under certain circumstances at temperate latitudes ( approximately 40 degrees ) in the winter hemisphere. The models, however, have hitherto been poorly constrained and their long-term predictions have not yet been observationally verified. Here we report that the global spatial cloud coverage on Titan is in general agreement with the models, confirming that cloud activity is mainly controlled by the global circulation. The non-detection of clouds at latitude approximately 40 degrees N and the persistence of the southern clouds while the southern summer is ending are, however, both contrary to predictions. This suggests that Titan's equator-to-pole thermal contrast is overestimated in the models and that its atmosphere responds to the seasonal forcing with a greater inertia than expected.

In Titan's atmosphere, the second most abundant constituent, methane, exists as a gas, liquid and solid, and cycles between the atmosphere and the surface. Similar to the Earth's hydrological cycle, Titan sports clouds, rain and lakes. Yet, Titan's cycle differs dramatically from its terrestrial counterpart, and reveals the workings of weather in an atmosphere that is 10 times thicker than the Earth's atmosphere, that is two orders of magnitude less illuminated, and that involves a different condensable. While ongoing measurements by the Cassini-Huygens mission are revealing the intricacies of the moon's weather, circulation, lake coverage and geology, knowledge is still limited by the paucity of observations. This review of Titan's methane cycle therefore focuses on measured characteristics of the lower atmosphere and surface that appear particularly perplexing or alien.

Fifty-nine RNA duplexes containing single-nucleotide bulge loops were optically melted in 1 M NaCl, and the thermodynamic parameters DeltaH degrees, DeltaS degrees, DeltaG 37 degrees, and TM for each sequence were determined. Sequences from this study were combined with sequences from previous studies [Longfellow, C. E., et al. (1990) Biochemistry 29, 278-285; Znosko, B. M., et al. (2002) Biochemistry 41, 10406-10417], thus examining all possible group I single-nucleotide bulge loop and nearest-neighbor sequence combinations. The free energy increments at 37 degrees C for the introduction of a group I single-nucleotide bulge loop range between 1.3 and 5.2 kcal/mol. The combined data were used to develop a model for predicting the free energy of a RNA duplex containing a single-nucleotide bulge. For bulge loops with adjacent Watson-Crick base pairs, neither the identity of the bulge nor the nearest-neighbor base pairs had an effect on the influence of the bulge loop on duplex stability. The proposed model for prediction of the stability of a duplex containing a bulged nucleotide was primarily affected by non-nearest-neighbor interactions. The destabilization of the duplex by the bulge was related to the stability of the stems adjacent to the bulge. Specifically, there was a direct correlation between the destabilization of the duplex and the stability of the less stable duplex stem. The stability of a duplex containing a bulged nucleotide adjacent to a wobble base pair also was primarily affected by non-nearest-neighbor interactions. Again, there was a direct correlation between the destabilization of the duplex and the stability of the less stable duplex stem. However, when one or both of the bulge nearest neighbors was a wobble base pair, the free energy increment for insertion of a bulge loop is dependent upon the position and orientation of the wobble base pair relative the bulged nucleotide. Bulge sequences of the type ((5'UBX)(3'GY)), ((5'GBG)(3'UU)) and ((5'UBU)(3'GG)) are less destabilizing by 0.6 kcal/mol, and bulge sequences of the type ((5'GBX)(3'UY)) and ((5'XBU)(3'YG)) are more destabilizing by 0.4 kcal/mol than bulge loops adjacent to Watson-Crick base pairs.

Spectra from Cassini's Visual and Infrared Mapping Spectrometer reveal the presence of a vast tropospheric cloud on Titan at latitudes 51 degrees to 68 degrees north and all longitudes observed (10 degrees to 190 degrees west). The derived characteristics indicate that this cloud is composed of ethane and forms as a result of stratospheric subsidence and the particularly cool conditions near the moon's north pole. Preferential condensation of ethane, perhaps as ice, at Titan's poles during the winters may partially explain the lack of liquid ethane oceans on Titan's surface at middle and lower latitudes.

Spectra from Cassini's Visual and Infrared Mapping Spectrometer reveal that the horizontal structure, height, and optical depth of Titan's clouds are highly dynamic. Vigorous cloud centers are seen to rise from the middle to the upper troposphere within 30 minutes and dissipate within the next hour. Their development indicates that Titan's clouds evolve convectively; dissipate through rain; and, over the next several hours, waft downwind to achieve their great longitude extents. These and other characteristics suggest that temperate clouds originate from circulation-induced convergence, in addition to a forcing at the surface associated with Saturn's tides, geology, and/or surface composition.

The smoggy stratosphere of Saturn's largest moon, Titan, veils its surface from view, except at narrow wavelengths centered at 0.83, 0.94, 1.07, 1.28, 1.58, 2.0, 2.9, and 5.0 micrometers. We derived a spectrum of Titan's surface within these "windows" and detected features characteristic of water ice. Therefore, despite the hundreds of meters of organic liquids and solids hypothesized to exist on Titan's surface, its icy bedrock lies extensively exposed.

Atmospheric conditions on Saturn's largest satellite, Titan, allow the possibility that it could possess a methane condensation and precipitation cycle with many similarities to Earth's hydrological cycle. Detailed imaging studies of Titan have hitherto shown no direct evidence for tropospheric condensation clouds, although there has been indirect spectroscopic evidence for transient clouds. Here we report images and spectra of Titan that show clearly transient clouds, concentrated near the south pole, which is currently near the point of maximum solar heating. The discovery of these clouds demonstrates the existence of condensation and localized moist convection in Titan's atmosphere. Their location suggests that methane cloud formation is controlled seasonally by small variations in surface temperature, and that the clouds will move from the south to the north pole on a 15-year timescale.

We have discovered frequent variations in the near-infrared spectrum of Titan, Saturn's largest moon, which are indicative of the daily presence of sparse clouds covering less than 1% of the area of the satellite. The thermodynamics of Titan's atmosphere and the clouds' altitudes suggest that convection governs their evolutions. Their short lives point to the presence of rain. We propose that Titan's atmosphere resembles Earth's, with clouds, rain, and an active weather cycle, driven by latent heat release from the primary condensible species.

Objective: TO evaluate the effects of a synthetic feline facial pheromone (FFP) on behavior and food intake of healthy versus clinically ill cats., Design: Original study., Animals: 20 cats were used in each of 2 studies. In each study, 7 cats were considered healthy, and 13 cats were determined to be clinically ill., Procedure: In study 1, cats were assigned either to exposure to FFP (treated group; 4 healthy, 6 ill cats) or to exposure to the vehicle (70% ethanol solution; control group; 3 healthy, 7 ill cats). Cats were placed in a cage containing a small cotton towel that had been sprayed with FFP or vehicle 30 minutes previously. Cats were then videotaped for 125 minutes, and food intake was measured during this period. Videotapes were scored at 5-minute intervals for various behaviors. In study 2, cats were categorized in 1 of 2 groups; group 1 (2 healthy, 8 ill cats) had a cat carrier placed in their cages, and group 2 (5 healthy, 5 ill cats) did not. All cats were exposed to FFP, and 24-hour food intake was measured., Results: Differences between behaviors of healthy versus clinically ill cats were not identified. In the first study, significant increases in grooming and interest in food were found in cats exposed to FFP compared with vehicle. For all cats, significant positive correlations were detected between grooming and facial rubbing, walking and facial rubbing, interest in food and facial rubbing, eating and facial rubbing, grooming and interest in food, and grooming and eating. In the second study, 24-hour food intake was significantly greater in cats exposed to FFP and the cat carrier, compared with cats exposed to FFP alone., Conclusions and Clinical Relevance: Results suggest that exposure to FFP may be useful to increase food intake of hospitalized cats.

The distribution of Cs in Gliese 229B's atmosphere reveals how equilibrium chemistry establishes the atmospheric composition. The rapid kinetics of cesium chemistry keeps the Cs abundance in thermochemical equilibrium and renders Cs a sensitive measure of chemical processes in brown dwarf atmospheres. Observations of Gliese 229B indicate a subsolar bulk abundance of Cs, the depletion of alkali metals in the upper atmosphere from condensation, and a partitioning of heavy elements different from that of the Sun.

The brown dwarf Gliese 229B has an observable atmosphere too warm to contain ice clouds like those on Jupiter and too cool to contain silicate clouds like those on low-mass stars. These unique conditions permit visibility to higher pressures than possible in cool stars or planets. Gliese 229B's 0.85- to 1.0-micrometer spectrum indicates particulates deep in the atmosphere (10 to 50 bars) having optical properties of neither ice nor silicates. Their reddish color suggests an organic composition characteristic of aerosols in planetary stratospheres. The particles' mass fraction (10(-7)) agrees with a photochemical origin caused by incident radiation from the primary star and suggests the occurrence of processes native to planetary stratospheres.

The 1980 encounter by the Voyager 1 spacecraft with Titan, Saturn's largest moon, revealed the presence of a thick atmosphere containing nitrogen and methane (1.4 and approximately 0.05 bar, respectively). Methane was found to be nearly saturated at Titan's tropopause, which, with other considerations, led to the hypothesis that Titan might experience a methane analogue of Earth's vigorous hydrological cycle, with clouds, rain and seas. Yet recent analyses of Voyager data indicate large areas of super-saturated methane, more indicative of dry and stagnant conditions. A resolution to this apparent contradiction requires observations of Titan's lower atmosphere, which was hidden from the Voyager cameras by the photochemical haze (or smog) in Titan's stratosphere. Here we report near-infrared spectroscopic observations of Titan within four narrow spectral windows where the moon's atmosphere is ostensibly transparent. We detect pronounced flux enhancements that indicate the presence of reflective methane condensation clouds in the troposphere. These clouds occur at a relatively low altitude (15+/-10 km), at low latitudes, and appear to cover approximately 9 per cent of Titan's disk.

We have reanalyzed the Voyager radio occultation data for Titan, examining two alternative approaches to methane condensation. In one approach, methane condensation is facilitated by the presence of nitrogen because nitrogen lowers the condensation level of a methane/nitrogen mixture. The resulting enhancement in methane condensation lowers the upper limit on surface relative humidity of methane obtained from the Voyager occultation data from 0.7 to 0.6. We conclude that in this case the surface relative humidity of methane lies between 0.08 and 0.6, with values close to 0.6 indicated. In the other approach, methane is allowed to become supersaturated and reaches 1.4 times saturation in the troposphere. In this case, surface humidities up to 100% are allowed by the Voyager occultation data, and thus the upper limit must be set by other considerations. We conclude that if supersaturation is included, then the surface relative humidity of methane can be any value greater than 0.08--unless a deep ocean is present, in which case the surface relative humidity is limited to less than 0.85. Again, values close to 0.6 are indicated. Overall, the tropospheric lapse rate on Titan appears to be determined by radiative equilibrium. The lapse rate is everywhere stable against dry convection, but is unstable to moist convection. This finding is consistent with a supersaturated atmosphere in which condensation-and hence moist convection-is inhibited.

We use a Monte Carlo model to simulate impact histories of possible Titans, Callistos, and Ganymedes. Comets create or erode satellite atmospheres, depending on their mass and velocity distributions: faster and bigger comets remove atmophiles; slower or smaller comets supply them. Mass distributions and the minimum total mass of comets passing through the Saturn system were derived from the crater records of Rhea and Iapetus. These were then scaled to give a minimum impact history for Titan. From this cometary population, of 1000 initially airless Titans, 16% acquired atmospheres larger than Titan's present atmosphere (9 x 10(21) g), and more than half accumulated atmospheres larger than 10(21) g. In contrasts to the work of Zahnle et al. (1992), we find that, in most trials, Callisto acquires comet-based atmospheres. Atmospheres acquired by Callisto and, especially, Ganymede are sensitive to assumptions regarding energy partitioning into the ejecta plume. If we assume that only the normal velocity component heats the plume, the majority of Ganymedes and half of the Callistos accreted atmospheres smaller than 10(20) g. If all the impactor's velocity heats the plume, Callisto's most likely atmosphere is 10(17) g and Ganymede's is negligible. The true cometary flux was most likely larger than that derived from crater records, which raises the probability that Titan, Ganymede, and Callisto acquired substantial atmospheres. However, other loss processes (e.g., sputtering by ions swept up by the planetary magnetic field, solar UV photolysis of hydrocarbons) are potentially capable of eliminating small atmospheres over the age of the solar system. The dark material on Callisto's surface may be a remnant of an earlier, now vanished atmosphere.

To investigate the chemistry and dynamics of Jupiter's Great Red Spot (GRS), the tropospheric abundances of NH3 and PH3 in the GRS are determined and compared to those of the surrounding region, the South Tropical Zone (STZ). These gases well up from deep in the atmosphere, and, in the upper troposphere, are depleted by condensation (in the case of NH3), chemical reactions, and UV photolysis. At Jupiter's tropopause, the chemical lifetimes of NH3 and PH3 are comparable to the time constant for vertical transport over the atmospheric scale height. The distributions of these gases are therefore diagnostic of the rate of vertical transport in the upper troposphere and lower stratosphere. Three groups of Voyager IRIS spectra are analyzed, two of the STZ and one of the GRS. The two groups of STZ spectra are defined on the basis of their radiances at 602 and 226 cm-1, which reflect, respectively, the temperature near 150 mbar and the cloud opacity in the 300-600 mbar region. One selection of STZ spectra is chosen to have the same radiance as does the GRS at 226 cm-1. The other STZ selection has a significantly greater radiance, indicative of reduced cloudiness. Variations in the abundances of NH3 and PH3 are determined within the STZ, as a background for our studies of the GRS. Within the uncertainty of our measurements (-55% and +75%), the PH3 mixing ratio at 600 mbar is 3 x 10(-7), the same for all three selections. The NH3 mixing ratio profile in the pressure region between 300 and 600 mbar is the same within error (-25% and +50% at 300 mbar) for both STZ selections. In the GRS, however, NH3 is significantly depleted at 300 mbar, with an abundance of 25% that derived for the STZ selections. Since the GRS is believed to be a region of strong vertical transport, our finding of a depletion of NH3 below the tropopause within the GRS is particularly unexpected. One of the STZ selections has a temperature-pressure profile similar to that of the GRS below the 300-mbar level; therefore, condensation at this level does not easily explain the low NH3 abundance in the GRS. All samples are taken at essentially the same latitude; photolysis and/or charged particle precipitation is probably not directly responsible either. The observed NH3 depletion may have a dynamical origin or result from some unidentified chemical processes at work in the GRS.

Microphysical simulations of Titan's stratospheric haze show that aerosol microphysics is linked to organized dynamical processes. The detached haze layer may be a manifestation of 1 cm sec-1 vertical velocities at altitudes above 300 km. The hemispherical asymmetry in the visible albedo may be caused by 0.05 cm sec-1 vertical velocities at altitudes of 150 to 200 km, we predict contrast reversal beyond 0.6 micrometer. Tomasko and Smith's (1982, Icarus 51, 65-95) model, in which a layer of large particles above 220 km altitude is responsible for the high forward scattering observed by Rages and Pollack (1983, Icarus 55, 50-62), is a natural outcome of the detached haze layer being produced by rising motions if aerosol mass production occurs primarily below the detached haze layer. The aerosol's electrical charge is critical for the particle size and optical depth of the haze. The geometric albedo, particularly in the ultraviolet and near infrared, requires that the particle size be near 0.15 micrometer down to altitudes below 100 km, which is consistent with polarization observations (Tomasko and Smith 1982, West and Smith 1991, Icarus 90, 330-333). Above about 400 km and below about 150 km Yung et al.'s (1984, Astrophys. J. Suppl. Ser. 55, 465-506) diffusion coefficients are too small. Dynamical processes control the haze particles below about 150 km. The relatively large eddy diffusion coefficients in the lower stratosphere result in a vertically extensive region with nonuniform mixing ratios of condensable gases, so that most hydrocarbons may condense very near the tropopause rather than tens of kilometers above it. The optical depths of hydrocarbon clouds are probably less than one, requiring that abundant gases such as ethane condense on a subset of the haze particles to create relatively large, rapidly removed particles. The wavelength dependence of the optical radius is calculated for use in analyzing observations of the geometric albedo. The lower atmosphere and surface should be visible outside of regions of methane absorption in the near infrared. Limb scans at 2.0 micrometers wavelength should be possible down to about 75 km altitude.

New observations of Titan's near-infrared spectrum (4000-5000 cm-1) combined with points taken from Fink and Larson's (1979) spectrum (4000-12500 cm-1) provide information on Titan's haze, possible clouds, surface albedo, and atmospheric abundance of H2. In the near-infrared, the main features in Titan's spectrum result from absorption of solar radiation by CH4. The strength of this absorption varies considerably with wavelength, allowing us to probe various atmospheric levels down to the surface itself by choosing specific wavelengths for analysis. At 4715 cm-1, the pressure-induced S(1) fundamental band of H2 lies in the wings of CH4 bands. Based on current values for the CH4 line parameters, Titan's spectrum can be best interpreted with a volume mixing ratio of H2 between 0.5 and 1.0%. Our observations suggest the existence of an optically thin CH4 cloud layer. The optical depths that we derive for Titan's haze and clouds are small enough to allow us to sense the surface of Titan at 4900, 6250, and 7700 cm-1. The most plausible interpretation of the albedos determined at these wavenumbers suggests a surface dominated by "dirty" water ice. A global ethane ocean is not compatible with these albedos.

In 178 patients undergoing elective cholecystectomy for biliary colic, the papilla was calibrated with a no. 10 French catheter through the cystic duct. The catheter passed through the papilla into the duodenum in 94 patients. Six (6 percent) had common duct stones. No postcholecystectomy colic occurred. In 37 patients the catheter was obstructed by papillary stenosis and sphincteroplasty was done. Common duct stones occurred in 17 patients (46 percent), jaundice in 7 and dilatation of the common duct in 6. Cholangiograms failed to detect small stones in seven patients and were of minimal value in positively identifying stenosis. In 49 control patients the papilla was not calibrated. Cholangiograms were normal. Postcholecystectomy colic occurred in seven patients, two of whom underwent subsequent sphincteroplasty. It is concluded that calibration is a worthwhile adjunct to cholangiography. Sphincteroplasty permits passage of small stones that may not be apparent on cholangiograms and are retained by papillary stenosis, and prevents colic (dyskinesia) of stenosis that also may not be apparent on cholangiograms.

A control group of 53 patients with selective vagotomy plus pyloroplasty was studied with pre- and postoperative cholecystography. At the fourth to seventh years the size and motility of the gallbladders were the same. Gallstones developed in two patients. A series of 91 patients with total vagotomy plus pyloroplasty was studied by similar methods. In 46 patients the gallbladders were grossly dilated and in 30 of the 46 the gallbladders were noncontractile. Gallstones developed in nine of the 46 patients. In the other 45 patients hypotonic dysfunction of the gallbladder was insignificant, and stones developed in only 1 of them. Explanation of these variable results is thwarted by unknown variations in the degree of both hypotonic dysfunction of the gallbladder and lithogenic change in the bile of patients with complete hepatic and complete celiac vagotomy after total vagotomy, and also by the unknown occurrence of incomplete hepatic and incomplete celiac vagotomy in series of allegedly complete total vagotomy. It is concluded that total vagotomy increases the incidence of gallstones, and that this increase occurs primarily in patients with significant hypotonia of the gallbladder. Selective vagotomy prevents these sequelae.

Among an initial series of 103 patients with selective vagotomy plus pyloroplasty for duodenal ulcer, 9 patients died of causes unrelated to ulcer and 7 were lost to follow-up without signs or symptoms of ulcer 8 to 15 years after operation; the remaining 87 patients were followed up for 12 to 17 years. Insulin testing revealed only one inadequate vagotomy in a patient who had a recurrence in the short term. Insulin tests were negative in 61 and negative or adequate in 6 other patients. Complete vagotomy reduced basal secretion effectively in the great majority of patients but not in a small minority. Three patients had antral hyperfunction with persistent hypersecretion despite complete vagotomy as indicated by two negative insulin tests in each patient. Inexplicably, only one of these patients had a stomal ulcer recurrence. Long-term follow-up revealed the development of gastric ulcer in one patient wit stasis from a pyloroplasty stenosed by angulation from adhesions. Three other patients, one with ulcer and two with hemorrhagic gastritis, developed gastric ulceration in the long term despite low acid output and negative insulin tests. Biliary reflux was demonstrated in two of these three patients and was probably the cause of gastric ulcer in the third. Pre- and postoperative cholecystograms in 66 patients showed the formation of gallstones in 4 patients after vagotomy. Another patient who did not undergo cholecystography developed acute cholecystitis from stone. This rate of gallstone formation was the normal expected rate and was not increased as in some series of total vagotomy. Dumping with and without associated diarrhea was the most frequent and troublesome sequela. Postvagotomy diarrhea did not occur. To prevent dumping, and also to decrease acid secretion more effectively, pyloroplasty was abandoned in favor of Maki's pyloruspreserving antrectomy to complement selective vagotomy in 1968.