This paper treats two-threshold policies for an M/G/1 queue with two types of generally distributed random vacations: type 1 (long) and type 2 (short) vacations. Upon returning from a vacation, the server observes the queue length. If this is less than the lower threshold, the server takes a type 1 vacation; if it is between the two thresholds, the server takes a type 2 vacation; and if it is a...

The inhibition of presynaptic calcium channels via G-protein-dependent second messenger pathways is a key mechanism of transmitter release modulation. We used the calyx-type nerve terminal of the chick ciliary ganglion to examine which G-proteins are involved in the voltage-sensitive inhibition of presynaptic N-type calcium channels. Adenosine caused a prominent inhibition of the calcium curren...

Osteoclasts are the cells responsible for the resorption of bone and other mineralized tissues. GTP-binding proteins (G proteins) play important roles in regulating the activity of many cell types; however, there is limited knowledge of their functions in osteoclasts. We used the patch-clamp technique in the whole-cell configuration to introduce either hydrolysis-resistant guanosine triphosphat...

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Types I, III, IV, and V collagen were isolated and characterized from eight normal dog hearts and seven with volume-overload hypertrophy. Animals with volume-overload hypertrophy were killed at a time when left ventricular end-diastolic pressure and stiffness were increased. The collagens were characterized by solubility properties, sodium dodecyl sulfate-polyacrylamide gel electrophoresis anal...

In this study, we compared leaf morphology and the phenolic and methylxanthine contents of different teas (Camellia sinensis (L.) Kuntze). Different tea types in loose leaf form available in the Italian market were investigated. The presence of numerous fine silvery-white hairs on the young leaves and buds, and the small-clavate glands on the leaf margins, light-colored and gelatinous in young ...

We analyze a batch arrival queue with a single server providing two kinds of general heterogeneous service. Just before his service starts, a customer may choose one of the services and as soon as a service (of any kind) gets completed, the server may take a vacation or may continue staying in the system. The vacation times are assumed to be general and the server vacations are based on Bernoul...

We study the workload process of the M/G/1 queueing system. Firstly, we give the explicit criteria for the geometric rate of convergence and the geometric decay of stationary tail. And the parameters ε 0 and s 0 for the geometric rate of convergence and the geometric decay of the stationary tail are obtained, respectively. Then, we give the explicit criteria for the rate of convergence and deca...

Abstract We consider an M/G/1 feedback queue with optional server vacations based on Bernoulli schedule and a single vacation policy. We assume that the server provides two types of service, type 1 with probability p1 and type 2 with probability p2 with the service times following general distribution and each arriving customer may choose either type of service. However after the completion of ...

A molecule of rabbit yG-globulin’ evidently consists of four polypeptide chains held together by interchain disulfide bonds and noncovalent interactions. Each molecule comprises a pair of similar or identical “light” chains having an approximate molecular weight of 20,000, and another pair of “heavy” chains of weight 50,000 to 55,000 (2-7). Each light chain is linked to a heavy chain and the tw...