The Histopathology of the Appendix in Children at Interval Appendectomy

Whilst most surgeons agree that conservative treatment of appendiceal abscess in children is an adequate treatment, the need for subsequent interval appendectomy is still controversial. We analyzed the histopathology in interval appendectomy in search of signs of inflammation. All patients admitted between 2010 and 2017 with appendiceal abscess and scheduled for interval appendectomy were reviewed. The specimens were evaluated for grade of inflammation, type and distribution of cellular infiltrate, presence of necrosis or hemorrhage and infiltrate in the serosa. Forty-two patients had appendiceal abscess and were treated conservatively. Seven underwent emergent appendectomy. Thirty-three out of 35 patients underwent elective interval appendectomy. Thirty-two specimens were revised. Carcinoid tumor or other malignant lesions were not found. All of them presented some amount of inflammation, grade 1 to 2 in 53%, grade 3 to 4 in 47%. Twenty-five percent of the specimens had signs of necrosis accompanied by hemorrhage and in more than the half (53%) the infiltrate extended to the serosa. Conclusions: Although the appendix was mostly found not macroscopically inflamed intraoperatively, histology confirmed a certain grade of inflammation even months after the conservative treatment. No correlation was found between histopathologic findings and lapse of time between abscess treatment and interval appendectomy.

Observations on the feeding behaviour of late-instar larvae of Choristoneura fumiferana

Laboratory observations revealed that late-instar larvae of the eastern spruce budworm (Choristoneura fumiferana (Clemens)) (Lepidoptera: Tortricidae) spend most of their time spinning, wandering, and resting; less than 10% is spent feeding. Larvae feed in a discontinuous pattern of short feeding bouts separated by much longer intervals of nonfeeding activity. Over a 2 h observation period, feeding bouts averaged 2.2 min and were separated by 17.4 min intervals for 4th-instar larvae as compared to 3.3 min bouts separated by 33.4 min intervals for 5th-instar larvae. The duration of a feeding bout was positively correlated with the duration of the subsequent interval, not with the duration of preceding intervals, suggesting that feeding-bout frequency is governed primarily by post-ingestion processes. It is postulated that short feeding bouts followed by long intervals limit the window for ingesting an efficacious dose of aerially applied insecticides such as Bacillus thuringiensis.

Distribution properties of the system failure time in a general shock model

In this paper we study some distribution properties of the system failure time in general shock models associated with correlated renewal sequences (Xn, Yn) . Two models, depending on whether the magnitude of the nth shock Xn is correlated to the length Yn of the interval since the last shock, or to the length of the subsequent interval to the next shock, are considered. Sufficient conditions under which the system failure time is completely monotone, new better than used, new better than used in expectation, and harmonic new better than used in expectation are given for these two models.

Distribution properties of the system failure time in a general shock model

In this paper we study some distribution properties of the system failure time in general shock models associated with correlated renewal sequences (X n, Y n) . Two models, depending on whether the magnitude of the nth shock X n is correlated to the length Y n of the interval since the last shock, or to the length of the subsequent interval to the next shock, are considered. Sufficient conditions under which the system failure time is completely monotone, new better than used, new better than used in expectation, and harmonic new better than used in expectation are given for these two models.

General shock models associated with correlated renewal sequences

In this paper we define and analyze a general shock model associated with a correlated pair (Xn, Yn) of renewal sequences, where the system fails when the magnitude of a shock exceeds (or falls below) a prespecified threshold level. Two models, depending on whether the nth shock Xn is correlated to the length Yn of the interval since the last shock, or to the length Yn of the subsequent interval until the next shock, are considered. The transform results, an exponential limit theorem, and properties of the associated renewal process of the failure times are obtained. An application in a stochastic clearing system with numerical results is also given.

General shock models associated with correlated renewal sequences

In this paper we define and analyze a general shock model associated with a correlated pair (Xn, Yn ) of renewal sequences, where the system fails when the magnitude of a shock exceeds (or falls below) a prespecified threshold level. Two models, depending on whether the nth shock Xn is correlated to the length Yn of the interval since the last shock, or to the length Yn of the subsequent interval until the next shock, are considered. The transform results, an exponential limit theorem, and properties of the associated renewal process of the failure times are obtained. An application in a stochastic clearing system with numerical results is also given.