Dropping probability of handoff calls and blocking probability of new calls are two important QoS measures for cellular networks. Call admission policies, such as fractional guard channel and uniform fractional guard channel policies are used to maintain the pre-specified level of QoS. Since the parameters of network traffics are unknown and time varying, the optimal number of guard channels is...

A 993-bp regulatory region upstream of the translation start codon of subtilisin-like serine protease gene was isolated from Gossypium barbadense. This (T/A)AAAG-rich region, GbSLSP, and its 5'- and 3'-truncated versions were transferred into tobacco and Arabidopsis after fusing with GUS or GFP. Histochemical and quantitative GUS analysis and confocal GFP fluorescence scanning in the transgenic...

Elevated carbon dioxide (CO2) in leaves closes stomatal apertures. Research has shown key functions of the β-carbonic anhydrases (βCA1 and βCA4) in rapid CO2-induced stomatal movements by catalytic transmission of the CO2 signal in guard cells. However, the underlying mechanisms remain unclear, because initial studies indicate that these Arabidopsis (Arabidopsis thaliana) βCAs are targeted to d...

In this paper we examine the effects of the required portions of guard timing spaces in a MAC frame of ETSI BRAN HIPERLAN/2 system such as inter-mobile guard timing space in UL(Up Link) duration, inter-RCH(Random CHannel) guard timing space, sector switch guard timing space. In particular, we calculate the number of OFDM(Orthogonal Frequency Division Multiplexing) symbols required for these gua...

The central issue in direct-sequence code-division multiple-access (DS-CDMA) ad hoc networks is the prevention of a near-far problem. This paper considers two types of guard zones that may be used to control the near-far problem: a fundamental exclusion zone and an additional CSMA guard zone that may be established by the carrier-sense multiple-access (CSMA) protocol. In the exclusion zone, no ...

In response to drought stress, the phytohormone abscisic acid (ABA) induces stomatal closure. Thereby the stress hormone activates guard cell anion channels in a calcium-dependent, as well as -independent, manner. Open stomata 1 protein kinase (OST1) and ABI1 protein phosphatase (ABA insensitive 1) represent key components of calcium-independent ABA signaling. Recently, the guard cell anion cha...

The IPv6 Router Advertisement Guard (RA-Guard) mechanism is commonly employed to mitigate attack vectors based on forged ICMPv6 Router Advertisement messages. Many existing IPv6 deployments rely on RA-Guard as the first line of defense against the aforementioned attack vectors. However, some implementations of RA-Guard have been found to be prone to circumvention by employing IPv6 Extension Hea...

Inward-rectifying potassium (K+(in)) channels in guard cells have been suggested to provide a pathway for K+ uptake into guard cells during stomatal opening. To test the proposed role of guard cell K+(in) channels in light-induced stomatal opening, transgenic Arabidopsis plants were generated that expressed dominant negative point mutations in the K+(in) channel subunit KAT1. Patch-clamp analys...

The presence of chloroplasts in guard cells from leaf epidermis, coleoptile, flowers, and albino portions of variegated leaves was established by incident fluorescence microscopy, thus confirming the notion that guard cell chloroplasts are remarkably conserved. Room temperature emission spectra from a few chloroplasts in a single guard cell of Vicia faba showed one major peak at around 683 nano...

Two immunological approaches were used to determine if ribulose bisphosphate carboxylase oxygenase (RuBisCo) is present in guard cell chloroplasts. Immunocytochemistry on thin plastic sections using tissue samples that were processed using traditional glutaraldehyde/osmium fixation and then restored to antigenicity with metaperiodate treatment, resulted in labeling over wild-type mesophyll and ...