High-Frequency Orographically Forced Variability in a Single-Layer Model of the Martian Atmosphere

A shallow water model with realistic topography and idealized zonal wind forcing is used to investigate orographically forced modes in the Martian atmosphere. Locally, the model reproduces well the climatology at the sites of Viking Lander I and II (VLl and VL2) as inferred from the Viking Lander fall and spring observations. Its variability at those sites is dominated by a 3-sol (Martian solar day) oscillation in the region of VLl and by a 6-sol oscillation in that of VL2. These oscillations are forced by the zonal asymmetries of the Martian mountain field. It is suggested that they contribute to the observed variability by reinforcing the baroclinic oscillations with nearby periods identified in observational studies. The spatial variability associated with the orographically forced oscillations is studied by means of extended empirical orthogonal function analysis. The 3-sol VL1 oscillation corresponds to a tropical, eastward-traveling, zonal-wavenumber one pattern. The 6-sol VL2 oscillation is characterized by two midlatitude, eastward-traveling, mixed zonal-wavenumber one and two and zonal-wavenumber three and four patterns, with respective periods near 6.1 and 5.5 sols. The corresponding phase speeds arc in agreement with the conclusions drawn from the VL2 observations

Nurse-sensitive outcomes of advanced practice

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72541/1/j.1365-2648.2000.01598.x.pd

Cost of Farm Crops

The present bulletin is an inquiry into the Cost of Farm Crops, as produced at the State Experiment Station, under the following conditions: 1. The crops were treated substantially as upon the farms ordinarily found in our state. 2. The labor was all charged against the fields at the uniform rate of 15 cents an hour for each man and team, or at the rate of $3 per day of ten hours. 3. Substitute the farmer anywhere in the state for the Experiment Station and charge his time and that of his team at the same rate, and the conditions, except soil and climate, are identical. The fields on which records are prepared and which enter into this bulletjn are as follows: Field No. I-Corn -- Field No. 2-Corn and hay -- Field No.3-Hay. -- Field No.6-Hay -- Field No.7-Wheat, oats, and rye. -- Field No.8-Corn

The Co-Evolution of Mars’ Atmosphere and Massive South Polar CO₂ Ice Deposit

A Massive CO₂ Ice Deposit (MCID) that rivals the mass of Mars’ current, 96% CO₂ atmosphere was recently discovered to overlie part of Mars’ southern H₂O cap [1]. The MCID is layered: a top layer of 1-10 m of CO₂, the Residual South Polar Cap (RSPC) [2], is underlain by ~10-20 m of H₂O ice, followed by up to three 100s-meter-thick layers of CO2 ice, separated by two layers of ~20-40 m of H₂O ice [3] (Fig. 1). Previous studies invoked orbital cycles to explain the layering, assuming the H₂O ice insulates and seals in the CO₂, allowing it to survive periods of high obliquity [3,4]. We also model that orbital cycles [5] drive the MCID’s development, but instead assume the MCID is in continuous vapor contact with the atmosphere rather than sealed. Pervasive meter-scale polygonal patterning and km-scale collapse pits observed on the sub-RSPC H₂O layer [1,3] are consistent with it being fractured and permeable to CO₂ mass flux. Using currently observed optical properties of martian polar CO₂ ice deposits [6], our model demonstrates that the present MCID is a remnant of larger CO₂ ice deposits laid down during epochs of decreasing obliquity that are eroded, liberating a residual lag layer of H₂O ice, when obliquity increases. With these assumptions, our energy balance model ex-plains why only the south polar cap hosts an MCID, why the RSPC exists, and the observed MCID stratigraphy. We use our model to calculate Mars’ pressure history and the age of the MCID

Compassion Satisfaction and Compassion Fatigue Among Critical Care Nurses

BACKGROUND Although critical care nurses gain satisfaction from providing compassionate care to patients and patients’ families, the nurses are also at risk for fatigue. The balance between satisfaction and fatigue is considered professional quality of life. OBJECTIVES To establish the prevalence of compassion satisfaction and compassion fatigue in adult, pediatric, and neonatal critical care nurses and to describe potential contributing demographic, unit, and organizational characteristics. METHODS In a cross-sectional design, nurses were surveyed by using a demographic questionnaire and the Professional Quality of Life Scale to measure levels of compassion fatigue and compassion satisfaction. RESULTS Nurses (n = 221) reported significant differences in compassion satisfaction and compassion fatigue on the basis of sex, age, educational level, unit, acuity, change in nursing management, and major systems change. CONCLUSIONS Understanding the elements of professional quality of life can have a positive effect on work environment. The relationship between professional quality of life and the standards for a healthy work environment requires further investigation. Once this relationship is fully understood, interventions to improve this balance can be developed and tested

Ocean Convective Available Potential Energy. Part II: Energetics of Thermobaric Convection and Thermobaric Cabbeling

The energetics of thermobaricity- and cabbeling-powered deep convection occurring in oceans with cold freshwater overlying warm salty water are investigated here. These quasi-two-layer profiles are widely observed in wintertime polar oceans. The key diagnostic is the ocean convective available potential energy (OCAPE), a concept introduced in a companion piece to this paper (Part I). For an isolated ocean column, OCAPE arises from thermobaricity and is the maximum potential energy (PE) that can be converted into kinetic energy (KE) under adiabatic vertical parcel rearrangements. This study explores the KE budget of convection using two-dimensional numerical simulations and analytical estimates. The authors find that OCAPE is a principal source for KE. However, the complete conversion of OCAPE to KE is inhibited by diabatic processes. Further, this study finds that diabatic processes produce three other distinct contributions to the KE budget: (i) a sink of KE due to the reduction of stratification by vertical mixing, which raises water column’s center of mass and thus acts to convert KE to PE; (ii) a source of KE due to cabbeling-induced shrinking of the water column’s volume when water masses with different temperatures are mixed, which lowers the water column’s center of mass and thus acts to convert PE into KE; and (iii) a reduced production of KE due to diabatic energy conversion of the KE convertible part of the PE to the KE inconvertible part of the PE. Under some simplifying assumptions, the authors also propose a theory to estimate the maximum depth of convection from an energetic perspective. This study provides a potential basis for improving the convection parameterization in ocean models

Ocean Convective Available Potential Energy. Part I: Concept and Calculation

Thermobaric convection (type II convection) and thermobaric cabbeling (type III convection) might substantially contribute to vertical mixing, vertical heat transport, and deep-water formation in the World Ocean. However, the extent of this contribution remains poorly constrained. The concept of ocean convective available potential energy (OCAPE), the thermobaric energy source for type II and type III convection, is introduced to improve the diagnosis and prediction of these convection events. OCAPE is analogous to atmospheric CAPE, which is a key energy source for atmospheric moist convection and has long been used to forecast moist convection. OCAPE is the potential energy (PE) stored in an ocean column arising from thermobaricity, defined as the difference between the PE of the ocean column and its minimum possible PE under adiabatic vertical parcel rearrangements. An ocean column may be stably stratified and still have nonzero OCAPE. The authors present an efficient strategy for computing OCAPE accurately for any given column of seawater. They further derive analytical expressions for OCAPE for approximately two-layer ocean columns that are widely observed in polar oceans. This elucidates the dependence of OCAPE on key physical parameters. Hydrographic profiles from the winter Weddell Sea are shown to contain OCAPE (0.001–0.01 J kg^(−1)), and scaling analysis suggests that OCAPE may be substantially enhanced by wintertime surface buoyancy loss. The release of this OCAPE may substantially contribute to the kinetic energy of deep convection in polar oceans