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Thermal conductivity measurements of a monocrystalline nonhomogeneous GaAs sample exhibit different conductivities with respect to the direction of heat flow across the sample. It is found that the same applied external temperature gradient causes two different distributions of the effective thermal conductivity coefficient, depending on the two opposite directions of heat flow. [Russian Text Ignored].

Knotenadmittanzmatrizen von technisch interessanten elektrischen Schaltungen sind schwach besetzt und von symmetrischer Struktur. Es wird gezeigt, wie durch Ausnutzung dieser speziellen Eigenschaften von Knotenadmittanzmatrizen Speicherbedarf und Rechenzeit bei der digitalen Schaltungssimulation erheblich verringert werden konnen. Die wesentlichen Ergebnisse von umfangreichen experimentellen Untersuchungen zur optimalen Knotennumerierung und Verbesserung der numerischen Genauigkeit werden gegenubergestellt. Zwei daraus fur die praktische Anwendung entwickelte Rechenrprogramme werden beschrieben: ein Programm, das durch einen vom Rechner erzeugten Maschinencode und als Folge davon durch sehr kurze Rechenzeiten gekennzeichnet ist und ein interpretatives Programm mit geringem Speicherbedarf, das besonders fur kleine Rechenanlagen geeignet ist.

Mild low-temperature proteolysis with pronase selectively dissociates ribosomes not attached to mRNA into 40S and 60S subunits, while ribosomes attached to mRNA are completely protected. The following characteristics of the resistance of mRNA-bound ribosomes to proteolytic dissociation were found: 1. 1. Ribosomes attached to fragments of mRNA are protected as well as those attached to intact mRNA, 2. 2. Single ribosomes attached to fragments of mRNA resist proteolytic dissociation as well as the intact polyribosomes from which they are derived, 3. 3. This protection is not dependent upon the presence of nascent chains on the ribosome, even when the ribosomes are attached to fragments of mRNA.

SUMMARY Prescalene lymph node biopsy is a procedure of established value in the diagnosis of intrathoracic disease and in determining resectability of previously diagnosed pulmonary malignant neoplasms. In 62 biopsies in 58 patients, 14 biopsies, or 22.6 per cent yielded abnormal lymph nodes. No operative or postoperative complication was encountered in our series, but three biopsies were inadequately performed as they were reported to contain no lymph nodes. These procedures should be performed by experienced surgeons.

Spontaneous rupture of the esophagus in the newborn has been infrequently reported. Review of the literature fails to reveal a report of esophageal perforation in the newborn due to trauma. Such a case is reported here. A 28-hour-old female infant weighing 6 pounds, 1 ounce was admitted in respiratory distress to the U.S. Naval Hospital, Philadelphia, from another activity on Oct. 17, 1959. Respirations were reported delayed at birth. The infant was aspirated with machine suction and received 1 cc. of caffeine sodiobenzoate, fairly normal respirations being established in 4 minutes. It was later ascertained that a stiff rubber catheter had been used for the aspiration. On admission to this hospital, the child continued to exhibit respiratory embarrassment with sternal retraction, despite continuous administration of oxygen. Breath sounds were markedly diminished on the right, and x-rays demonstrated a right tension pneumothorax (Fig. 1). Thoracentesis was immediately performed, and with continuous