ArcTiCA: Arctic tidal constituents atlas.

Tides in the Arctic Ocean affect ocean circulation and mixing, and sea ice dynamics and thermodynamics. However, there is a limited network of available in situ tidal coefficient data for understanding tidal variability in the Arctic Ocean; e.g., the global TICON-3 database contains only 111 sites above 60°N and 21 above 70°N. At the same time, the presence of sea ice and latitude limits of satellite altimetry complicate altimetry-based retrievals of Arctic tidal coefficients. This leads to a reliance on ocean tide models whose accuracy depend on having sufficient in situ data for validation and assimilation. Here, we present a comprehensive new dataset of tidal constituents in the Arctic region, combining analyses of in situ measurements from tide gauges, ocean bottom pressure sensors and GNSS interferometric reflectometry. The new dataset contains 914 measurement sites above 60°N and 399 above 70°N, with each site being quality-assessed and expert guidance provided to help maximise the usage of the dataset. We also compare the dataset to recent tide models.

Offsets in tide-gauge reference levels detected by satellite altimetry: ten case studies.

Comparing measurements of absolute sea level by satellite altimetry and relative sea level by a tide gauge can reveal errors in either measurement system. Combining the measurements can determine vertical land motion (VLM) at the tide gauge. We here discuss ten case studies in which a tide gauge has likely experienced a small (≤10 cm), discontinuous offset in the vertical, suggesting inadvertent loss of reference-level stability. Proper interpretation of offsets is helped if independent VLM measurements from nearby geodetic stations are available. In two cases, earthquake-induced VLM cannot be ruled out, although it appears unlikely. Offsets as small as 1-2 cm can be detected when both altimeter and tide gauge successfully observe the same ocean signal. This is most likely to occur for tide gauges located on small, open-ocean islands. Tide gauges near large land masses are typically more challenging owing to inadequacies of satellite altimetry near land and to differences between coastal and open-ocean sea levels. The case studies highlight the utility of satellite altimetry for tide-gauge quality control. Supplementary Information: The online version contains supplementary material available at 10.1007/s00190-023-01800-7.

Tests of ocean-tide models by analysis of satellite-to-satellite range measurements: An update.

Seven years of GRACE intersatellite range-rate measurements are used to test the new ocean tide model FES2014 and to compare against similar results obtained with earlier models. These qualitative assessments show that FES2014 represents a marked improvement in accuracy over its earlier incarnation, FES2012, with especially notable improvements in the Arctic Ocean for constituents K1 and S2. Degradation appears to have occurred in two anomalous regions: the Ross Sea for the O1 constituent and the Weddell Sea for M2.

A Simulation-based, cognitive assessment of resident decision making during complex urinary catheterization scenarios.

BACKGROUND: This study explores general surgery residents' decision making skills in uncommon, complex urinary catheter scenarios. METHODS: 40 residents were presented with two scenarios. Scenario A was a male with traumatic urethral injury and scenario B was a male with complete urinary blockage. Residents verbalized whether they would catheterize the patient and described the workup and management of suspected pathologies. Residents' decision paths were documented and analyzed. RESULTS: In scenario A, 45% of participants chose to immediately consult Urology. 47.5% named five diagnostic tests to decide if catheterization was safe. In scenario B, 27% chose to catheterize with a 16 French Coude. When faced with catheterization failure, participants randomly upsized or downsized catheters. Chi-square analysis revealed no measurable consensus amongst participants. CONCLUSIONS: Residents need more training in complex decision making for urinary catheterization. The decision trees generated in this study provide a useful blueprint of residents' learning needs. SUMMARY: Exploration of general surgery residents' decision making skills in uncommon, complex urinary catheter scenarios revealed major deficiencies. The resulting decision trees reveal residents' learning needs.

Recent Greenland ice mass loss by drainage system from satellite gravity observations.

Mass changes of the Greenland Ice Sheet resolved by drainage system regions were derived from a local mass concentration analysis of NASA-Deutsches Zentrum für Luftund Raumfahrt Gravity Recovery and Climate Experiment (GRACE mission) observations. From 2003 to 2005, the ice sheet lost 101 +/- 16 gigaton/year, with a gain of 54 gigaton/year above 2000 meters and a loss of 155 gigaton/year at lower elevations. The lower elevations show a large seasonal cycle, with mass losses during summer melting followed by gains from fall through spring. The overall rate of loss reflects a considerable change in trend (-113 +/- 17 gigaton/year) from a near balance during the 1990s but is smaller than some other recent estimates.

Attenuation of frontal asymmetry in pediatric posttraumatic stress disorder.

BACKGROUND: Volumetric imaging research has shown abnormal brain morphology in adults with posttraumatic stress disorder (PTSD) when compared with matched control subjects. In this article, we present brain imaging findings from a study of children with PTSD symptoms. METHODS: Twenty-four children between the ages of 7 and 14 with a history of trauma and PTSD symptoms were assessed with the Clinician-Administered PTSD Scale for Children and Adolescents (CAPS-CA). The sample underwent magnetic resonance imaging in a 1.5 T scanner. Brain images were analyzed by raters blind to diagnostic status using well-standardized methods, and images were compared with age- and gender-matched healthy control subjects. RESULTS: The clinical group demonstrated attenuation of frontal lobe asymmetry and smaller total brain and cerebral volumes when compared with the control group. There were no statistically significant differences in hippocampal volume between clinical and control subjects. CONCLUSIONS: Frontal lobe abnormalities may occur as a result of PTSD in children or, alternatively, be a risk factor for the development of the syndrome in this age group. The implications of the findings and their consistency with previous research are discussed.

Diurnal and Semidiurnal Variations in the Earth's Rotation Rate Induced by Oceanic Tides.

Recent space-geodetic observations have revealed daily and subdaily variations in the Earth's rotation rate. Although spectral analysis suggests that the variations are primarily of tidal origin, comparisons to previous theoretical predictions based on various ocean models have been less than satisfactory. This disagreement is partly caused by deficiencies in physical modeling. Rotation predictions based on a reliable tidal-height model, with corresponding tidal currents inferred from a modified form of Laplace's momentum equations, yield predictions of tidal variations in Universal Time that agree with very long baseline interferometer observations to 2 microseconds. This agreement resolves a major discrepancy between theory and observation and establishes the dominant role of oceanic tides for inducing variation in the Earth's rotation at these frequencies.

Integrating behavior and cardiovascular responses: the code.

The next revolution in biology is predicted to be in the integrative domain, and the need to involve physiologists in this kind of research has been recognized. This paper represents an approach to providing some of the tools required for dealing with integrative physiology at the behavioral level. Video tape recordings are made of the activities of a group of five baboons (Papio hamadryas) while simultaneous recordings of arterial blood pressure, heart rate, renal blood flow, and mesenteric or iliac blood flow are telemetered from two of the members of the group. The telemetered cardiovascular information is recorded on the two audio channels of the videotape. Subsequently the videotape is viewed, and a two-dimensional code is used to record the behavior of the two animals with the telemetry equipment. The first dimension of the code categorizes the behavior changes precisely regarding those aspects of behavior that are related to cardiovascular dynamics and does so with an accuracy of 16 ms. The second dimension codes relevant environmental changes. The paper describes the code and presents illustrations of how the code reflects the cardiovascular dynamics associated with the behavioral changes.

The function of the anconeus muscle.

The purpose of the present study is to determine whether the anconeus muscle contracts during abduction of the ulna. Abduction of the ulna occurs when pronation takes place around an axis passing through the head of the radius and the second digit. This is in contrast to pronation around an axis passing through the fifth digit, in which the ulna remains relatively stationary. Electromyograms of the anconeus were obtained from five subjects with the elbow supported in 90 degrees of flexion, in full extension, at rest, during supination-pronation around an axis passing through the fifth digit, and during motion around an axis through the second digit. Pronation of the forearm around the axis through the second digit resulted in the greatest amplitude of individual motor unit action potentials and the highest recruitment of additional action potentials. These findings provide evidence substantiating the function of the anconeus muscle as an abductor of the ulna.

Low (type III) odontoid fracture: a new radiographic sign.

Dens fractures are frequently difficult to identify radiographically, particularly when it is only possible to obtain a lateral radiograph of the upper cervical spine. Further, when a dens fracture is identified in lateral projection, it is often difficult to distinguish the "high" (Type II) from the "low" (Type III) fracture. The authors describe an elongated "ring" density superimposed upon the body of the axis in the lateral cervical radiograph which, when horizontally disrupted, indicates a dens fracture and is a specific radiographic sign of the "low" variety.

The theory and practice of safe handling temperatures.

Many hot objects which may be touched or handled every day can cause either discomfort, pain or burning of the skin. The precise effect will depend on the Contact Temperature tC, an intermediate value between the hot object and the skin temperature. The value of tC varies with the material, and is governed by the Contact Coefficient b, a property of the material which has a wide range of values from metals to plastics. In the experiments with 48 female subjects, surface and contact temperatures for three materials were measured over a wide range, and subject reactions recorded on a five-point comfort scale. From the heat conduction theory outlined, and using the calculated values of b for the three materials, the predicted safe surface temperatures were determined. These predicted values were then compared with the observed temperatures and with those recommended in British Standards.

An approach to mid-facial fractures.

The purpose of this article is to present a concept which facilitates the plain film identification of mid-face fractures. The concept evolves from a logical classification of mid-face fractures based upon the region(s) of involvement (orbit, zygoma, maxilla), the extent of the fractures (unilateral or bilateral) and the characteristic distribution of the fracture lines. Recognition of these fractures depends upon an awareness of the fact that the radiographic signs of mid-face fractures differ in certain respects from those involving other skeletal parts. In addition to skeletal disruption, the radiographic signs of mid-face fractures include soft tissue abnormalities which may be localized or diffuse, and which may be either extrinsic or intrinsic to the facial skeleton, alterations of normal skeletal contour, the "bright white line" of displaced fragments, and the subcutaneous emphysema which may also be localized or diffuse. The application of this concept to the roentgen diagnosis of mid-face fractures will be described and illustrated.

Experimental use of adhesives in the repair of transverse fractures of the rat and rabbit.

In this preliminary study, the feasibility of fixing fractured bones was explored using the ethyl and isobutyl 2-cyano-acrylates, prepolymerized barnacle cement, and fibrin glue. Adequate cohesive strength cannot be obtained when lipids are present on the surface to be joined by alkyl 2-cyanoacrylates. Oxidized regenerated cellulose gauze soaked in a highly concentrated fibrinogen solution was inserted into the partially hollowed fracture ends to arrest the flow of oozing blood from the medullary canal. Anhydrous ether was used to sponge off any residual lipid from the bone surfaces. The displaced fracture ends were aligned and narrow strips of bone were secured around the fracture line resulting in a barrel stave arrangement. Roentgenograms indicated successful reduction of transverse (midshaft) fractures in eight rat (femur) and seven rabbit (tibia) models. In some cases, casts were used as supplementary fixation. Using the ethyl and isobutyl 2-cyanoacrylates, reduced fractures were maintained in a stable position for up to five and six days, respectively. Further study of the 2-cyanoacrylates is recommended. By using a standardized surgical method for testing the usefulness of future adhesives in vivo, consistent interpretation of results will be facilitated.

Experimental hyperextension supracondylar fractures in monkeys.

Discarded monkey autopsy specimens were used to investigate the mechanism of supracondylar hyperextension fracture. As the fracture progressed from mild angulation to complete lateral or medial displacement, the anterior periosteum first was detached from the bone and then stripped distally before tearing over the edge of the proximal fragment. Stability or reduction by acute elbow flexion and forearm pronation, owing to compressive forces, was transmitted through the elbow joint on the medial side of the fracture, and stability was not significantly influenced by a bridging periosteal hinge or forearm musculature. Forearm supination and elbow flexion of less than 90 degrees resulted in less stability. The influence of acute elbow flexion and forearm pronation was diminished when the fracture was distracted by traction. Interposition of the anterior periosteum in displacement fractures prevented anatomic reduction.

Myelography of spinal block from epidural tumor: a new approach.

Eleven patients with spinal canal block from metastatic epidural tumor, documented with Pantopague myelography, were given an additional injection of up to 5 cc of air. This technique forced contrast material past the block in 10 of 11 cases. It failed in one case in which symptoms had been present for 19 days. Air injection allowed visualization of more cephalad lesions and defined the superior extent of the initial obstructing lesion without the need for a lateral cervical or cisternal puncture. It caused transient discomfort but no neurologic deterioration. This technique is less painful, requires less patient cooperation, expedites localization, and does not require the special skills needed for cervical puncture.

Intraosseous pressure in the lumbar spine.

Intraosseus pressure in the lumbar spine is defined as the hydrostatic pressure of venous blood in the trabecular sinusoids of cancellous bone. Measurements of it in the lumbar vertebrae and the inferior vena cava confirm that the intraosseus pressure in the lumbar spine is identical to, and dependent upon, the pressure in the inferior vena cava. With Valsalva maneuver in the decubitus position, the pressure reaches levels of 90 mm Hg in the inferior vena cava and intraosseus space of lumbar spine.

Correlation of arthroscopy with other diagnostic modalities.

In our experience arthroscopy proved to be the most reliable method of evaluating internal derangement of the knee. Among 96 patients who underwent arthrotomy, the arthroscopic diagnosis was confirmed in 96 per cent. The combined anteromedial, anterolateral, and posteromedial approaches consistently demonstrated all intraarticular disorders. We found the posterolateral approach of little benefit.