A dust-enshrouded tidal disruption event with a resolved radio jet in a galaxy merger.

Tidal disruption events (TDEs) are transient flares produced when a star is ripped apart by the gravitational field of a supermassive black hole (SMBH). We have observed a transient source in the western nucleus of the merging galaxy pair Arp 299 that radiated >1.5 × 1052 erg at infrared and radio wavelengths but was not luminous at optical or x-ray wavelengths. We interpret this as a TDE with much of its emission reradiated at infrared wavelengths by dust. Efficient reprocessing by dense gas and dust may explain the difference between theoretical predictions and observed luminosities of TDEs. The radio observations resolve an expanding and decelerating jet, probing the jet formation and evolution around a SMBH.

Herschel detects a massive dust reservoir in supernova 1987A.

We report far-infrared and submillimeter observations of supernova 1987A, the star whose explosion was observed on 23 February 1987 in the Large Magellanic Cloud, a galaxy located 160,000 light years away. The observations reveal the presence of a population of cold dust grains radiating with a temperature of about 17 to 23 kelvin at a rate of about 220 times the luminosity of the Sun. The intensity and spectral energy distribution of the emission suggest a dust mass of about 0.4 to 0.7 times the mass of the Sun. The radiation must originate from the supernova ejecta and requires the efficient precipitation of all refractory material into dust. Our observations imply that supernovae can produce the large dust masses detected in young galaxies at very high redshifts.

X-ray illumination of the ejecta of supernova 1987A.

When a massive star explodes as a supernova, substantial amounts of radioactive elements--primarily (56)Ni, (57)Ni and (44)Ti--are produced. After the initial flash of light from shock heating, the fading light emitted by the supernova is due to the decay of these elements. However, after decades, the energy powering a supernova remnant comes from the shock interaction between the ejecta and the surrounding medium. The transition to this phase has hitherto not been observed: supernovae occur too infrequently in the Milky Way to provide a young example, and extragalactic supernovae are generally too faint and too small. Here we report observations that show this transition in the supernova SN 1987A in the Large Magellanic Cloud. From 1994 to 2001, the ejecta faded owing to radioactive decay of (44)Ti as predicted. Then the flux started to increase, more than doubling by the end of 2009. We show that this increase is the result of heat deposited by X-rays produced as the ejecta interacts with the surrounding material. In time, the X-rays will penetrate farther into the ejecta, enabling us to analyse the structure and chemistry of the vanished star.

Occupational injuries to senior farmers in Sweden.

The prevailing demographic change in the western world means that the workforce is becoming older. Farmers in particular often work beyond the normal retirement age, in a challenging physical environment. For example, the agricultural sector has the most hazardous work environment in Sweden. Therefore, it is interesting to examine the following questions: Are senior farmers more frequently involved in work-related injuries? Do some injuries happen more often in the oldest age group? Which part of the body is most frequently affected in different age groups? What can be done to decrease the risk of injury in senior farmers?

Riding instructors, their musculoskeletal health and working conditions.

UNLABELLED: The aim of this study was to gain a deeper understanding of riding instructors' working conditions, work load, and frequency of musculoskeletal problems and to identify potential risk factors for the development of musculoskeletal problems. A questionnaire was mailed to 800 instructors in Sweden containing questions on their work environment, work tasks, work load, and musculoskeletal symptoms. The Borg CR-10 scale was used to estimate the work load, and the Standardized Nordic Questionnaire was used to analyze the occurrence of musculoskeletal symptoms. Perceived symptoms were most frequently reported to be in the shoulders (60%), lower back (56%), and neck (52%) during the past 12 months; 91% of the riding instructors had experienced symptoms from at least one of nine anatomical areas during the past 12 months and 55% in the seven days prior to answering the questionnaire. Removal of manure from the stable was considered to be the task involving the heaviest work, and 14.5% had suffered an injury at work during the past year. The risk of developing musculoskeletal problems was 50% less for those who did physical exercise at least two hours a week besides riding (OR = 0.47, CI 0.25-0.89). CONCLUSIONS: The prevalence of symptoms was high, considering the low median age (33 years). Reducing workload, guarding against injury, and performing other exercises besides riding could be important measures for the prevention of musculoskeletal symptoms in this particular group of workers.

Slow-moving vehicles in Swedish traffic.

The objective of this study was to reach a better understanding of accidents on Swedish roads involving slow-moving vehicles and to suggest ways of preventing such accidents. We analyzed accident data from a 5-year period (1992-1996) involving all types of farm vehicles as well as horses and horse-drawn vehicles. During each year of the period under investigation, slow-moving vehicles were involved in more than 250 traffic accidents on Swedish roads, and an average of 10 people were killed, 66 sustained serious injuries, and 192 sustained slight injuries. This was about 1.3% of all persons injured in traffic accidents in Sweden. The deaths and injuries mostly involved car drivers and passengers. Tractor drivers and unprotected road users (people walking or traveling by motorcycle, moped, or bicycle) also sustained serious injuries and deaths. Vehicles overtaking slow-moving vehicles from behind were the most common type of accident (30%), followed by turning accidents (27%), accidents at crossroads (26%), and with oncoming vehicles (17%). To strengthen the suggestions for improvement, a questionnaire was sent out to driving school teachers in Sweden. Subjects were asked about their experiences with farm vehicles on the roads and their suggestions for ways to increase traffic safety. Based on the accident data and the questionnaire responses, we developed several suggestions for reducing road accidents, including measures for making farm vehicles more visible, improvement of the training provided at driving schools, and information campaigns directed at drivers of farm vehicles and other road users. Further in-depth research is needed to analyze road accidents involving slow-moving vehicles and to test different intervention measures.

Occupational health and safety of workers in agriculture and horticulture.

Working in agriculture and horticulture gives considerable job satisfaction. The tasks are often interesting; you can see the result of your own work, watch your crop grow and mature; you have an affinity with nature and can follow the changes in the seasons. However, today it is a dangerous work environment fraught with occupational injuries and diseases due to hazardous situations and to physiological, physical, biological, chemical, psychological, and sociological factors. The ongoing rapid development may, on the other hand, bring about many changes during the next decades with more farmers and growers switching to organic production. Moreover, increased awareness of animal welfare also may lead to improved working conditions. Large-scale operations with fewer family-operated agricultural businesses might mean fewer injuries among children and older farmers. A consequence of large-scale operations may also be better regulation of working conditions. The greater use of automation technology eliminates many harmful working postures and movements when milking cows and carrying out other tasks. Information technology offers people the opportunity to gain more knowledge about their work. Labeling food produced in a worker-friendly work environment may give the consumers a chance to be involved in the process.

Evaluation of a workplace redesign of a grocery checkout system.

The aim of this study was to evaluate the effects on the working postures and movements of a cashier when two different locations of the scales (one to the left of the cashier, the other under the conveyer belt in front of the cashier) were used in a grocery checkout system. Two cashiers (of average stature and short stature) were videotaped while working, in both sitting and standing working positions. Analysis of the video tapes was performed using the WOPALAS method and video observations. The results of the study show that the design of the checkout system with the scales under the conveyer belt provides a more favourable working position for both the taller and the shorter cashier. Additionally, the results indicate that a standing position is more favourable than a sitting one for the taller cashier while for the shorter cashier the sitting position is better.

Salivary duct carcinoma.

Twelve cases of salivary duct carcinoma were examined clinically, pathologically and by flow cytometry to quantify their histological features as well as attempt to identify factors predictive of patient outcome. All of the tumours arose in the parotid gland. Eight of the twelve patients were male. Four patients died of disease (median survival 12.5 months); three are alive with disease; and five are alive with no evidence of disease (mean follow-up of 50 months). Two tumours arose in a pre-existing pleomorphic adenoma. Positive lymph nodes were present in eight of ten patients sampled; patients with two or more positive lymph nodes tended to die of their disease or be alive with metastases. Comedo necrosis, perineural invasion and vascular invasion were common findings by light microscopy. Ten of the twelve tumours were aneuploid. Neither clinical stage, tumour size, aneuploidy nor histological features correlated with patient outcome. This study confirms the aggressive nature of salivary duct carcinoma.

Titanium copings veneered with Procera ceramics: a longitudinal clinical study.

In 1989, 47 titanium copings veneered with a low-fusing ceramic were fabricated for 24 patients. Forty-four crowns could be examined after a period varying between 26 and 30 months. It was found that the bulk ceramic of two crowns had fractured. California Dental Association ratings for "Surface and Color" had changed markedly from the "Excellent" to the "Acceptable" level, and for "Anatomic Form" there was a small shift from the "Excellent" to the "Acceptable" level. The factor of "Margin Integrity" was recorded as "satisfactory" for all crowns and a large majority were rated "Excellent."

A 1-year clinical examination of indirect composite resin inlays: a preliminary report.

Twenty-three patients received 45 heat- and pressure-cured composite resin inlays. Approximately 6 months after placement of the inlays, 34 of the inlays (in 19 patients) were examined according to the criteria of the California Dental Association and also for bleeding upon probing. At least 12 months later, 30 inlays (in 16 patients) were reexamined. At the first examination, 28 inlays were rated excellent, three were rated acceptable, and three were rated unsatisfactory. At the second examination, 21 were found to be excellent, eight were acceptable, and one was unsatisfactory. One inlay had been fractured before the first examination, but no other fractured inlays were observed. Except for slightly discolored margins in six inlays, excellent color match and smooth, glossy surfaces were found in most of the restorations.

A 3-year clinical study of alternatives to high noble dental casting alloys type 3.

For the purpose of evaluating the quality of dental casting alloys, 22 patients were recalled for clinical examination 3 years after insertion of crowns and bridges made from the low-gold alloy Midas and the silver-palladium alloy Albacast. A high-gold alloy, JS C, served as a reference alloy. The examination included registrations of tarnish, plaque index, gingival index, and margin index. In addition, the California Dental Association's quality evaluation of dental care was used by two independent calibrated examiners. From the results of the present study it can be concluded that the crowns made from the alloy Midas in the annealed condition and the alloy Albacast are well suited for clinical use. Some tarnish appeared, but this may occur intermittently.

A clinical comparison of alternative alloys.

For the purpose of evaluating the clinical performance of 2 alternative dental casting alloys, 17 crowns made from the low-gold alloy Midas and 14 crowns made from the silver-palladium alloy Albacast were inserted at random into 23 patients. In each patient a high-gold type-3 alloy, JS C, served as a reference alloy. The patients were examined after 1 year with regard to tarnishing and certain factors such as plaque index, gingival index, and margin index. In addition, the California Dental Association's quality evaluation of dental care was used by two independent calibrated examiners. The results of the present study showed that the crowns made of the silver-palladium alloy were tarnished and had rough occlusal surfaces more often than crowns made of the low-gold and high-gold alloys.

Association of high cyanide and low sulphur intake in cassava-induced spastic paraparesis.

Urinary excretion of sulphur compounds was studied in children from a population in Mozambique that had been affected, during a drought, by an epidemic of spastic paraparesis attributed to cyanide exposure from cassava. The children had increased thiocyanate and decreased inorganic sulphate excretion, indicating high cyanide and low sulphur-containing amino-acid intake. Children from a neighbouring cassava-eating area, where no cases of spastic paraparesis had occurred, had lower thiocyanate excretion but higher inorganic sulphate excretion. These results support the hypothesis that the epidemic was due to the combined effects of high dietary cyanide exposure and sulphur deficiency.

Sequential methotrexate-5-fluorouracil treatment of squamous cell carcinoma of the head and neck.

Thirty-six patients with squamous cell carcinoma of the head and neck were treated with sequential methotrexate-5-fluorouracil followed by leucovorin rescue. The frequency of objective tumor regression obtained was 64% (complete response + partial response) with 19% complete regression. In 20 not previously treated patients, the objective response rate was 70%. Approximately the same result was obtained for tumors of different anatomical sites of the head and neck. The degree of differentiation of the squamous cell carcinoma did not seem to be of prognostic importance for the initial tumor response. Toxicity was very mild and usually disappeared when the interval between the chemotherapy courses was prolonged from 1 to 2 weeks. Radiotherapy could be added sequentially to the treatment without measurable escalated toxicity.

The excretion of sulfur compounds in the urine of newborn infants.

The excretion of sulfur-containing compounds was determined on the third and sixth day of life in male infants and the results were compared with those previously obtained on fed and fasting men. The output of total sulfur and inorganic sulfate was very low on the third day of life but had increased by the sixth day to levels found in the fasting men, whereas the excretion of mercaptolactate in the newborns decreased from the third to the sixth day of life. These results may be explained by the initial fasting state of neonates followed by an anabolic phase. Neonates excreted acid-labile ester sulfate and mercaptoacetate at levels similar to those found in adults, but the neonatal urine also contained sulfate esters (probably steroid sulfates) that required more drastic acid conditions for hydrolysis. Raised concentrations of sulfur-containing amino acids (methionine, cystathionine, cyst(e)ine and taurine) were found in neonatal urine in confirmation of earlier reports. The excretion of thiosulfate could only be determined in newborns on the sixth day and was low in comparison with that of adults. High urinary thiocyanate concentrations were found in newborns fed by tobacco-smoking mothers, whereas the excretion of thiocyanate was low in other newborns. The possible medical hazards from the exposure of neonates to thiocyanate are emphasized.

Ultrastructural aspects of capillary function in irradiated bowel. An experimental study in the cat.

Irradiated small intestine of the cat has decreased capillary function measured as capillary filtration. This decrease may be due to changes in capillary permeability or decreased capillary area. An electron microscopic study was carried out to examine whether there were any ultrastructural changes consistent with impaired permeability. Cat ileum was irradiated with doses from 10 to 25 Gy and examined 4 days, 1 month, and 4 months after irradiation. In the acute phase (4 days) degenerative endothelial changes were seen and increased with dose. Congestion and microthrombi were also observed. One month after irradiation endothelial changes were still seen after 20 and 25 Gy, and an aggregation of fibrous matter adjacent to the capillary wall was prominent. The endothelial changes were subtle after 4 months, but the pericapillary and stromal fibrosis increased, and an increasing number of collagen fibrils appeared. Micropores disappeared after 20 and 25 Gy but returned later. Pinocytic vesicles were observed after all doses and intervals. The initial decrease in capillary filtration coefficient after irradiation may partly be due to permeability changes caused by endothelial degeneration, whereas the late decrease parallels the increasing pericapillary fibrosis.

A clinical re-examination of patients treated with pinledge-crowns.

A group consisting of forty patients received a clinical and radiological re-examination, of a cross-sectional type, to examine the effects of pinledge-crowns on teeth and periodontal tissues. The mean age of the material, which consisted of patients treated at the Department of Prosthetics, University of Umeå, during the period February 1969-November 1971, was 48.6 years (18 male, 22 female). In these patients fifty-one pinledge-crowns had been inserted, in 88% of the cases on a canine tooth. In every person, the contralateral tooth served as a control tooth. The teeth were examined with regard to the frequency of failure (expressed as failure rate %/year), the presence of caries, and the periodontal status. The results showed that of the total number of pinledge-crowns (fifty-one), twelve had been removed before the time of examination. At the examination it was found that one crown had extensive caries, which required a revision of the crown, and one tooth had a non-sensitive pulp with a periapical osteitis. These fourteen (27.5%) pinledge-crowns were classified as failures. The value of the failure rate expressed as %/year was, after 8 years, 3.43 pinledge/year or 3.13, if the patient was used as a unit. Concerning the periodontal effects, the difference between teeth fitted with pinledge-crowns and control teeth was small.