Pulsating Mass Research Articles

Head injury secondary to ruptured abdominal aortic aneurysm: an unusual presentation

A 65-year-old male was admitted to the Accident and Emergency department following a road traffic accident in which his car hit a telegraph pole. It would appear that he collapsed at the whee1 just before the impact. He was wearing a seat belt. On arrival he was agitated and non-responsive with a BP of 100/50mmHg and a pulse rate of 104 beats/min. There was a large frontal laceration with an underlying haematoma. A rapid primary survey did not appear to reveal any other major injuries. A diagnosis of head injury was made. X-rays of the skull, cervical spine, chest, lumbar spine and pelvis were unhelpful. While the patient was still in the accident department he went into asystole. He was successfully resuscitated and at that point was noticed to have a large pulsating peri-umbilical mass. A diagnosis of ruptured abdominal aortic aneurysm was made. He was transferred immediately to the operating theatre. At laparotomy the presence of a large retroperitoneal haematoma associated with a ruptured infrarenal aortic aneurysm was noted. There was no free blood in the peritoneal cavity and no evidence of other intra-abdominal injuries. The aneurysm was repaired in standard fashion by a knitted Dacron tube graft and a total of 16 units of blood was transfused. After operation he was still ventilated and transferred to the X-ray department for a CT scan of the head which revealed no intra-cranial collection. He was returned to the intensive care unit and was ventilated for 3 days. His post-operative course was stormy, being complicated by a chest infection and jaundice, but he subsequently went on to make a good recovery and was discharged 24 days after operation. On review in the out-patient department 12 months later, he remains well.

Aneurysm of the cranial mesenteric artery in a cow

An exploratory laparotomy of a four-year-old red Holstein cow with signs of abdominal discomfort revealed a painful pulsating mass in the cranial part of the abdomen. The cow died suddenly. A post mortem examination showed that a ruptured aneurysm of the cranial mesenteric artery had been the cause of death.

Cepheid Variables: Period and Mass Determination

Determination of masses has been a long standing problem in the Cepheid research. Since the early days of Cepheid modeling different methods of mass calibration have lead to conflicting results, implying serious discrepancies between the evolution and pulsation theories (see Cox 1980 for a review). In recent years this situtation has been mostly remedied, and the Baade-Wesselink masses, pulsation masses and evolutionary masses are now in good agreement with each other (e.g., Gieren 1989). However, both the bump masses inferred from the position of the secondary bump on the light curve and the beat masses obtained from the period ratios of the double mode Cepheids turned out to be very resilient to a reconciliation.There are 13 Cepheids in the Galaxy in which two vibrational modes are simultaneously excited (e.g., Szabados 1988). The period ratios measured in these variables can be used in conjunction with the linear pulsation theory to infer the masses of these stars. The method was first applied by Petersen (1973) who obtained masses ranging from 1Mʘ to 3Mʘ for Cepheids with fundamental mode periods between 2.1 d and 6.3 d. Such ‘beat” masses are 2—4 times smaller than the evolutionary or Baade-Wesselink masses for these objects.

False aneurysm of the profunda femoral artery after intertrochanteric fracture of the femur

An 83-year-old lady suffered a fall in which she sustained a closed intertrochanteric fracture of the right femur. She was treated with a dynamic hip screw internal fixation (Fig. 1). She then underwent two operations to evacuate a femoral haematoma. Unfortunately she was transfused with incompatible blood and was transferred to a medical department and treated briefly with steroids. Her haemoglobin, however, continued to fall and a pulsating mass in

Horizontal Branch Evolution and RR Lyrae Star Pulsation

For many years there has been a confrontation between stellar evolution and pulsation theories concerning the masses, luminosities, and compositions of the horizontal branch RR Lyrae variables. Masses obtained by Cox, Hodson & Clancy (CHC, 1983) were very low, but Kovacs (1985) and later Kovacs & Buchler (1988) suggested somewhat larger ones. Even later Simon & Cox (1991) verified CHC results, though still using the Los Alamos opacities. Petersen (1991, 1992) has also discussed this mass problem in some detail. The persistent discrepancy of 0.1 Mʘ or more between the evolution and pulsation masses was mostly ignored because neither theory could find any significant flaw in its analysis. Cox (1991), Kovacs, Buchler & Marom (1991), and Kovacs, Buchler, Marom, Iglesias & Rogers (1992) finally showed that larger double-mode pulsation masses, are consistent with evolution calculations to reproduce color-magnitude diagrams of globular clusters. Evolution tracks by many for years, especially the recent ones by Lee, Demarque & Zinn (1990), did require a much lower primordial helium abundance near the big bang value near Y = 0.23, and now this value, slightly enhanced by deep convection dredge-up in the earlier red giant stage, is also found to be appropriate for pulsation studies.

ANEURYSMS OF BILATERAL DEEP FEMORAL ARTERIES WITH THE RUPTURED RIGHT ANEURYSM -REPORT OF A CASE-

Aneurysm rarely occurs in the deep femoral artery, especially bilaterally. We experienced aneurysms of the bilateral deep femoral arteries, of which right aneurysm ruptured. A 66-year-old man was seen at the hospital because of bilateral femoral pulsating masses. CT revealed aneurysms of the bilateral deep femoral arteries and operation was scheduled. Few days later, right femoral pain and gait disturbance suddenly occurred. Emergency operation was carried out. The right aneurysm was partially excised and the inflow and outflow arteries of the aneurysm were closed. The left one was resected and the gap was bridged with a 8mm hemashield graft. The histological examination of the two resected tissues revealed arteriosclerotic aneurysms. Aneurysm of the deep femoral artery is often asymptomatic and sometimes it presents with its rupture, in that we should not hesitate to take surgical procedure. For future possible stenosis and obstruction of the superficial femoral arteries and popliteal arteries, it is important the restore the continuity of the deep femoral arteries, whenever possible.

Traumatic arteriovenous fistulae: “The Lebanese War Experience”

Over a 16-year period from January 1975 to December 1990, 823 patients with 840 vascular injuries were treated at the American University of Beirut Medical Center. Of these, 661 injuries involved peripheral vessels; 26 of which had 31 arteriovenous fistulae (AVF). Most of the AVF (80%) were diagnosed within 1 year from the injury. The most common presenting symptom was a thrill (74%) followed by a pulsating mass (32%). The most commonly affected vessels were the femoral and popliteal arteries. Angiograms were used preoperatively to delineate the extent and location of the fistulae. All patients except three, underwent surgical repair with excellent results with no limb loss. None of the patients developed late complications such as claudication or a vascular deficit in the involved limb. Arteriovenous fistula is a rare but challenging condition following vascular trauma. Its recognition and treatment give excellent results.

頭蓋内静脈環流異常を伴った高位頚静脈球症

We treated a 54-year-old female with a high right jugular bulb combined with contralateral abnormal Intracranial venous circulation and discuss the pathogenesis of high jugular bulb. This patient had an episode of right myringoplasty in 1987, and in the course of that surgery, no abnormal mass was found in the middle ear cavity. Six years after surgery, a pulsating blue mass protruding from the hypotympanum was found by an otologist, and she was referred to our clinic with suspected glomus tumor. CT scan showed a mass protruding from the right jugular fossa. Internal carotid artery angiography on both sides revealed expansion and dilation of the right jugular bulb in the venous phase without any abnormality of the arterial system. In the venous phase of left internal carotid artery angiography, an obstruction of the ipsilateral intracranial venous system was observed from the bifurcation of the transverse sinus to the jugular vein. These findings suggest that the abnormality of intracranial venous circulation may result in the development of the high jugular bulb. Intracranial venous obstruction may cause an increase of the contralateral venous blood flow, and this increase of blood flow may result in expansion and protrusion of the jugular bulb into the hypotympanum.

Nonlinear RR Lyrae models with new livermore opacities

A. N. Cox recently showed that a 20% opacity decrease in the 20,000-30,000 K region as indicated by the new Livermore OPAL opacities reconciles the discrepancy between pulsation and evolution masses of double-mode RR Lyrae variables. Nonlinear hydrodynamic calculations were performed for RR Lyrae models of mass 0.75M ⊙, 51L ⊙, andZ = 0.0001 (Osterhoff II type) including this opacity decrease. The Stellingwerf periodic relaxation method was used to converge the models to a limit cycle, and the Floquet matrix eigenvalues calculated to search for a tendency of the fundamental mode to grow from the full-amplitude overtone solution, and the overtone mode to grow from the full-amplitude fundamental solution, thereby predicting double-mode behavior. Models ofT eff < 7000 K with the opacity decrease have positive fundamental-mode growth rates in the overtone solution, in contrast to earlier results by Hodson and Cox (1982), and models withT eff > 7000 have positive 1st overtone growth rates in the fundamental-mode solution, but double-mode behavior was not found.

Pacific Coast Surgical Association

SURGEONS WHO have been members of the Pacific Coast Surgical Association (PCSA) have made significant contributions to the development of modern vascular surgery during the past 40 years. From 1953 to 1993, 147 articles on vascular surgery topics have been presented at the annual meetings of the association. Time will only permit the presentation of those PCSA surgeons and topics that I consider to have been of significant importance in the evolution of modern vascular surgery. I shall never forget the indelible experience I had as a third-year medical student in the surgical admitting ward of the then Los Angeles County General Hospital in 1947. Several classmates and I were making evening teaching rounds with an attending physician, a professor of medicine who took us to the bedside of a critically ill patient with excruciating abdominal pain, shock, and an expanding pulsating upper abdominal mass. We were told that this

The distance to the Large Magellanic Cloud - Constraints from Cepheids in Large Magellanic Cloud star clusters

We have used recent observational data for the Cepheids in the rich, young Large Magellanic Cloud clusters NGC 1866 and NGC 2031 to constrain the cluster distances with the mass-equivalency (ME) method. The basis of this approach is to fix the cluster distances by requiring the Cepheid evolutionary and pulsational masses to be equal. Using evolutionary models incorporating a mild amount of core and envelope over-shooting along with recent pulsational models, we derive distance moduli of 18.51 +/- 0.21 and 18.32 +/- 0.20 for NGC 1866 and NGC 2031, respectively. The quoted errors are dominated by the uncertainties in the heavy element abundances of the clusters (assumed to be 0.3 dex for both clusters), with a smaller contribution due to the apparently intrinsic spread in the masses of the Cepheids in each cluster. For the ME method, we find that {DELTA}(m - M)-0_/δZ_1_ = 0.69, where Z_1_ = log (Z/0.016). This result implies that the cluster distances can be determined to better than +/- 5% if the cluster abundances can be measured to better than about +/- 0.15 dex. The distance moduli we derive for NGC 1866 and NGC 2031 are consistent with other recent values derived for the LMC, meaning that the models used in this analysis avoid the classical evolutionary/pulsational Cepheid mass discrepancy. The results of our analysis are based on models using the Los Alamos opacities; had we used models incorporating the new Livermore opacities instead, we estimate that the cluster distance moduli would be larger by at most 0.1 mag.

Theoretical models of Cepheid variables and their BVI(c) colors and magnitudes

view Abstract Citations (161) References (48) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Theoretical Models of Cepheid Variables and Their BVI C Colors and Magnitudes Chiosi, C. ; Wood, P. R. ; Capitanio, N. Abstract Pulsation models for Cepheid variables have been constructed and used to derive PMR and associated relations and the positions of the instability strips. Theoretical quantities have been transformed into observational UBVR(c)I(c) magnitudes and colors. The instability strips for three modes of pulsation have been obtained, and analytical fits to the effective temperature and luminosity along the blue and red edges of the instability strips are presented. The use of new Cepheid models and of the mass-period-luminosity-color relations leads to a good determination of the pulsational mass of the Cepheid stars. The problem of mass discrepancy can likely be solved by the adoption of mild-to-large overshoot models to derive the evolutionary mass. It is suggested that abundance-dependent studies that rely on B-V as a color should be treated with caution. It is recommended that V-I be used as a color. Publication: The Astrophysical Journal Supplement Series Pub Date: June 1993 DOI: 10.1086/191790 Bibcode: 1993ApJS...86..541C Keywords: Cepheid Variables; Stellar Color; Stellar Luminosity; Stellar Magnitude; Stellar Mass; Stellar Oscillations; Bolometers; Magellanic Clouds; Stellar Interiors; Astrophysics; STARS: INTERIORS; STARS: OSCILLATIONS; STARS: VARIABLES: CEPHEIDS full text sources ADS | data products SIMBAD (3)

Nonlinear RR Lyrae Models with New Livermore Opacities

AbstractA. N. Cox recently showed that a 20% opacity decrease in the 20,000–30,000 K region as indicated by the new Livermore OPAL opacities reconciles the discrepancy between pulsation and evolution masses of double-mode RR Lyrae variables. Nonlinear hydrodynamic calculations were performed for RR Lyrae models of mass 0.75M⊙, 51L⊙, andZ= 0.0001 (Osterhoff II type) including this opacity decrease. The Stellingwerf periodic relaxation method was used to converge the models to a limit cycle, and the Floquet matrix eigenvalues calculated to search for a tendency of the fundamental mode to grow from the full-amplitude overtone solution, and the overtone mode to grow from the full-amplitude fundamental solution, thereby predicting double-mode behavior. Models ofTeff&lt; 7000 K with the opacity decrease have positive fundamental-mode growth rates in the overtone solution, in contrast to earlier results by Hodson and Cox (1982), and models withTeff&gt; 7000 have positive 1st overtone growth rates in the fundamental-mode solution, but double-mode behavior was not found.

Nonlinear Radiative RR Lyrae Models: A Search for Double-Mode Behavior

Cox (1991), Kovacs, Buchler, and Marom (1991), and Kovacs et al. (1992) showed that opacity changes indicated by the Livermore OPAL opacities increase the pulsation masses of double-mode RR Lyrae variables. We calculated limiting amplitude solutions for radiative RR Lyrae models of 0.75 M⊙, 51 L⊙, and Z=0.0001 (Oosterhoff II) to investigate the effects of the mass increase and opacity changes suggested by the OPAL opacities. In particular, we modified the Stellingwerf analytical fit (1975) to the Cox-Tabor (1976) tables to decrease the opacity by 20% between 20,000 and 30,000 K. The Stellingwerf periodic relaxation method was used to converge the models to a limit cycle, and the Floquet matrix analysed to search for a tendency of the fundamental mode to grow from the full-amplitude overtone solution, and the overtone to grow from the full-amplitude fundamental mode solution, thereby predicting double-mode behavior.

Masses and ages of delta scuti stars in eclipsing binary systems

By using data mainly from Frolovet al. (1982) for four Delta Scuti stars in eclipsing binary systems, AB Cas, Y Cam, RS Cha, and AI Hya, their physical parameters, distances, and radial pulsation modes are determined. The evolutionary track systems of Iben (1967), Paczynski (1970), and Maeder and Meynet (1988) are interpolated, in order to estimate evolutionary massesM eand agest of these variables. Their pulsation massesM Qare estimated from the fitting formulae of Faulkner (1977) and Fitch (1981). Our estimates of evolutionary massesM eand pulsation massesM Qare close to the massesM determined by Frolovet al. (1982) from the star binarity. The only exception is AB Cas, for which there is no agreement between certain star parameters. Another, independent approach is also applied to the stars RS Cha and AI Hya: by using their photometric indicesb — y andc 1 from the catalogue of Lopez de Cocaet al. (1990) and appropriate photometric calibrations, other sets of physical parameters, distances, modes, ages, evolutionary and pulsation masses of both variables are obtained.

The delta scuti-star HD 220392: a possible component of a binary system

Physical parameters and distances are determined for the stars HD 220391 and HD 220392, which possibly form a physical pair. Ages and evolutionary masses in the new track system of Schalleret al. (1992) as well as gravitational masses of both stars are evaluated. Distance and age estimates of this possible binary system are obtained: 128(±12) pc and 7.9(±0.8) × 108 yr. Both stars are located within the Delta Scuti instability strip on the H-R diagram, but a variability was only detected in HD 220392 by Lampens (1992). The pulsation mode(s) and the pulsation mass of this variable star cannot be determined at the present time.

Dacron Graft Aneurysm: A Report of Five Cases

Dacron prostheses have been long used in vascular surgery. The usual com plications concerning prosthetic vascular grafts are infection and anastomotic pseudoaneurysm formation. The authors present an unusual complication, namely, Dacron graft aneurysm. Five patients had been operated on eleven, ten, ten, nine, and seven years previously because of atherosclerotic occlusive dis ease ; an aortobifemoral reconstruction had been done in 4 patients and an axil lofemoral reconstruction in 1 patient—all with a Dacron prosthesis. The presenting symptom was abdominal pain in 1 case and a pulsating mass in 2 cases. In 2 cases the aneurysms were noticed during the angiography and repair operation of inguinal pseudoaneurysm formation. In 2 cases the reconstruction was made with an inlay technique for the Y-graft repair, in 1 case only the limbs of the Y-graft were reconstructed, and in 2 cases axillofemoral graft reconstruc tion was done. All 5 patients recovered from the operation.

What do Mira Variables Tell us About the Late Evolution of Low Mass Stars?

(1)Mira variables define the tip of the AGB for low mass stars (cf. Feast and Whitelock 1987 fig. 1).(2)The kinematics of Mira variables are a function of period (e.g. Feast 1989 and earlier references) and for Miras in globular clusters the period is a function of metallicity (e.g. Feast 1981). Hence the Mira period sequence is not an evolutionary sequence but represents the sequence of AGB tips for stars of different initial mass and/or chemical composition and/or age.(3)Mira are surrounded by circumstellar dust shells. The mass loss rates are a function of period and light amplitude (Whitelock et al. 1987, Whitelock et al. 1991, Whitelock 1990). The results suggest evolution with increasing pulsation amplitude and mass loss but little change in log P ((2) and (3) do not preclude some (small) change in log P during evolution nor possible phases of decreasing light amplitude and mass loss).

咽頭異常感を主訴とした内頚動脈蛇行症例

A 62-year-old woman visited our hospital complaining of abnormal sensation in the pharynx. Physical examination revealed a pulsating mass on the right side of the posterior wall of the mesopharynx. CT and angiography confirmed that the internal carotid artery had an abnormal course and was compressing the pharyngeal wall.The clinical importance and etiology of tortuosity of the internal carotid artery are discussed.

On the mass discrepancy of the Cepheid stars

The problem of the mass discrepancy of Cepheid stars in the young, rich LMC cluster NGC 2157, which is known to possess three Cepheids, is examined. The simultaneous fit of the color-magnitude diagram with theoretical simulations based on models for intermediate-mass stars incorporating either semiconvection or overshoot in the central cores, and with suited chemical composition, and tha derivation of the pulsational masses from the Cepheid models of Choisi & Wood allow us to show that the problem of mass discrepancy likely originates from the adoption of semiconvective models and insufficient accuracy in the determination of the mass by one of the two methods