Digital Commons Network^™

The Importance Of Vertical And Shared Leadership Within New Venture Top Management Teams: Implications For The Performance Of Startups, Michael D. Ensley, Keith M. Hmieleski, Craig L. Pearce

Department of Management: Faculty Publications

The current study investigated the relative influence of vertical versus shared leadership within new venture top management teams on the performance of startups using two different samples. Vertical leadership stems from an appointed or formal leader of a team (e.g., the CEO), whereas shared leadership is a form of distributed leadership stemming from within a team. Transformational, transactional, empowering, and directive dimensions of both vertical and shared leadership were examined. New venture performance was considered in terms of revenue growth and employee growth. The first sample was comprised of 66 top management teams of firms drawn from Inc. Magazine’s …

Why Is The Number Of Dna Bases 4?, Bo Deng

Department of Mathematics: Faculty Publications

In this paper we construct a mathematical model for DNA replication based on Shannon’s mathematical theory for communication. We treatDNAreplication as a communication channel. We show that the mean replication rate is maximal with four nucleotide bases under the primary assumption that the pairing time of the G–C bases is between 1.65 and 3 times the pairing time of the A–T bases.

Myxozoan Genera: Definition And Notes On Taxonomy, Life-Cycle Terminology And Pathogenic Species, Jiří Lom, Iva Dyková

Harold W. Manter Laboratory of Parasitology: Library Materials

A list of myxozoan genera is presented in the current taxonomical scheme. These genera are defined; their type species and most important pathogens along with their hosts are listed. Simultaneously, definitions of actinospore stages representing sexual stages of the myxosporean life cycle are given; altogether, 17 actinospore collective groups with 180 types have been described. Life cycles of the two classes of the phylum Myxozoa, Malacosporea and Myxosporea, are briefly outlined with specification of the appropriate terms. Up to now, 4 malacosporean and 2,180 myxosporean species assigned to a total of 62 genera, have been established. The surviving classification of …

Analyses Of Cry1ab Binding In Resistant And Susceptible Strains Of The European Corn Borer, Ostrinia Nubilalis (Hübner) (Lepidoptera: Crambidae), Herbert A. A. Siqueira, Joel Gonzalez-Cabrera, Juan Ferre, Ronald Flannagan, Blair Siegfried

Department of Entomology: Faculty Publications

Cry1Ab toxin binding analysis was performed to determine whether resistance in laboratory-selected Ostrinia nubilalis strains is associated with target site alteration. Brush border membrane vesicles were prepared using dissected midguts from late instars of susceptible and resistant strains (Europe-R and RSTT) of O. nubilalis. Immunoblot analysis indicated that three different proteins bound to Cry1Ab toxin and were recognized by an anticadherin serum. In a comparison of resistant and susceptible strains, reduced Cry1Ab binding was apparent for all three bands corresponding to cadherin-like proteins in the Europe-R strain, while reduced binding was apparent in only one band for the RSTT …

An Update On The Distribution And Diversity Of Bombus In Nebraska (Hymenoptera: Apidae), Douglas A. Golick, Marion D. Ellis

Department of Entomology: Faculty Publications

From 1999–2002, the University of Nebraska Department of Entomology, Folsom’s Children Zoo, and Lincoln Public Schools Science Focus High School initiated a program called Bumble Boosters. Forty schools participated to conduct a general survey of Nebraska bumble bees to: 1) determine whether the 20 species of bumble bees previously identified can still be found in Nebraska, 2) collect in areas that were not included in previous surveys, and 3) discover any additional species in the state. This study provides an update to previous surveys including; new distribution maps for species, and a discussion of findings.

Genetic And Morphological Comparisons Of New And Old World Populations Of Spalangia Species (Hymenoptera: Pteromalidae), David B. Taylor, Roger Moon, Gary Gibson, Allen L. Szalanski

Department of Entomology: Faculty Publications

The genetic similarity of New and Old World samples of Spalangia spp. (Hymenoptera: Pteromalidae) was examined using two ribosomalDNAregions. The species examined were Spalangia cameroni Perkins, Spalangia endius Walker, Spalangia gemina Bouček, Spalangia nigra Latreille, Spalangia nigroaenea Curtis, and Spalangia slovaca Bouček. Two species of Muscidifurax, Muscidifurax raptor Girault & Sanders and Muscidifurax zaraptor Kogan & Legner (Hymenoptera: Pteromalidae) were included as outgroup taxa. The internal transcribed spacer (ITS)-1 region was highly variable among Spalangia species with many insertions/deletions making alignment of the sequences difÞcult. The D2-D3 region of the 28s ribosomal gene and the nuclear rDNA 18s gene were …

Long-Term Reduction Of Trypanosoma Cruzi Infection In Sylvatic Mammals Following Deforestation And Sustained Vector Surveillance In Northwestern Argentina, L. A. Ceballos, M. V. Cardinal, G. M. Vazquez-Prokopec, M. A. Lauricella, M. M. Orozco, M. Roberto Cortinas, A. G. Schijman, M. J. Levin, Uriel Kitron, R. E. Gürtlera

Department of Entomology: Faculty Publications

Long-term variations in the dynamics and intensity of sylvatic transmission of Trypanosoma cruzi were investigated around eight rural villages in the semiarid Argentine Chaco in 2002–2004 and compared to data collected locally in 1984–1991. Of 501 wild mammals from 13 identified species examined by xenodiagnosis, only 3 (7.9%) of 38 Didelphis albiventris opossums and 1 (1.1%) of 91 Conepatus chinga skunks were infected by T. cruzi. The period prevalence in opossums was fourfold lower in 2002–2004 than in 1984–1991 (32–36%). The infection prevalence of skunks also decreased five-fold from 4.1–5.6% in 1984–1991 to 1.1% in 2002–2004. Infection in opossums increased …

Effects Of Temperature On Development Of Phormia Regina (Diptera: Calliphoridae) And Use Of Developmental Data In Determining Time Intervals In Forensic Entomology, P. D. Nabity, Leon G. Higley, Tiffany M. Heng-Moss

Department of Entomology: Faculty Publications

Precise developmental data for forensic indicator blow fly species are essential for accuracy in the estimate of the post-mortem interval (PMI). Why, then, does the determination of the PMI result in conflicting time frames when published conspecific developmental data are used? To answer this question, we conducted constant temperature trials between the developmental minimum temperature and upper threshold temperatures (8-32 degrees C) on the forensically important blow fly species Phormia regina (Meigen) (Diptera: Calliphoridae). Flies were reared using two designs to quantify sources of variation. We measured rearing container temperatures and internal growth chamber temperatures by using thermocouples to accurately …

Oil-Soluble Dyes For Marking Spodoptera Frugiperda (Lepidoptera: Noctuidae), Elis Christine Vilarinho, Odair Aparecido Fernandes, Celso Omoto, Thomas E. Hunt

Department of Entomology: Faculty Publications

Although various biological aspects of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) have been examined, adult movement and dispersal of this insect pest is not well understood. Release-recapture techniques by using marked insects is a useful approach for dispersal studies; however, the marking technique should not significantly affect insect biology or behavior. Therefore, the effect of different concentrations of oil-soluble dyes (Solvent Blue 35 [C.I. 61554], Sudan Red 7B [C.I. 26050], Sudan Black B [26150], Sudan Orange G [C.I. 11920], and Sudan I 103624 [C.I. 12055]) on development, mortality, and fecundity of S. frugiperda was evaluated. Dyes were added to artificial …

Temperature Effect On Kinetics Of Uptake, Transfer, And Clearance Of [14C]Noviflumuron In Eastern Subterranean Termites (Isoptera: Rhinotermitidae), Neil A. Spomer, Shripat T. Kamble

Department of Entomology: Faculty Publications

[¹⁴C]Noviflumuron uptake, clearance, rate of excretion, and transfer from treated to untreated termite workers were evaluated at 15, 19, 23, and 27°C. Feeding units were constructed from plastic containers provisioned with washed sand, distilled water, [¹⁴C]noviflumuron-treated feeding discs (0.05 or 0.5% [AI]), and Reticulitermes flavipes (Kollar) workers. Feeding units were held in environmental growth chambers preset at 15, 19, 23, and 27°C. The amount of [¹⁴C]noviflumuron present within R. flavipes was measured by scintillation counting and subsequently quantified. Uptake of noviflumuron by R. flavipes workers at 15°C was ≈2.8 times less than at 19 …

Partner-Driven Agricultural Research-For-Development Networks In West Africa: The Case Of Rocariz, L. T. Narteh, M. Winslow, Ousmane Youm, S. O. Keya

Department of Entomology: Faculty Publications

Agricultural research feeds the knowledge base that underpins food security and rural employment across sub-Saharan Africa. However, in West Africa, many national agricultural research programs (NARS) are small and have insufficient resources to carry out well-rounded, in-depth research programs. Since the crops, cropping systems and food needs of these countries have much in common, there is a clear opportunity for sharing knowledge and capacities for mutual benefit through networks.

However, conventional crop-based networks in sub-Saharan Africa were mainly mechanisms for centralized dissemination and testing of technologies, an approach that treated NARS as dependent recipients of research outputs generated by international …

Relative Index Of Susceptibility To The Maize Weevil, Sitophilus Zeamais, Among Some Qpm Corn Lines, Jamilton P. Santos, Paulo E. O. Guimaraes, Jose M. Waquil, John E. Foster

Department of Entomology: Faculty Publications

The maize weevil, Sitophilus zeamais, is one important pest of stored corn grain. It is difficult to control and causes large weight and nutritional losses to the grains. The discovery of the gene Opaque-2 (O-2) that enhances the protein quality with Lysine and Tryptophane opened new perspectives to use corn to feed monogastric animals and for human nutrition. However, the soft and farinaceous consistency of the endosperm in the O-2 gene corn increased the susceptibility to maize weevil. To solve this problem the O-2 gene was transferred to normal corn. This new corn was called Quality Protein Maize (QPM). …

Automated Generation Of Context-Aware Tests, Zhimin Wang, Sebastian Elbaum, David Rosenblum

School of Computing: Technical Reports

The incorporation of context-awareness capabilities into pervasive applications allows them to leverage contextual information to provide additional services while maintaining an acceptable quality of service. These added capabilities, however, introduce a distinct input space that can affect the behavior of these applications at any point during their execution, making their validation quite challenging. In this paper, we introduce an approach to improve the test suite of a context-aware application by identifying context-aware program points where context changes may affect the application’s behavior, and by systematically manipulating the context data fed into the application to increase its exposure to potentially valuable …

A New Cryptographic Scheme For Securing Dynamic Conferences In Data Networks, Sarang Deshpande, Ajay Todimala, Ravi K Balachandran, Byrav Ramamurthy, Xukai Zou, N. V. Vinodchandran

School of Computing: Conference and Workshop Papers

Dynamic conferencing refers to a scenario wherein any subset of users in a universe of users form a conference for sharing confidential information among themselves. The key distribution (KD) problem in dynamic conferencing is to compute a shared secret key for such a dynamically formed conference. In literature, the KD schemes for dynamic conferencing either are computationally unscalable or require communication among users, which is undesirable. The extended symmetric polynomial based dynamic conferencing scheme (ESPDCS) is one such KD scheme which has a high computational complexity that is universe size dependent. In this paper we present an enhancement to the …

Router And Firewall Redundancy With Openbsd And Carp, Garhan Attebury, Byrav Ramamurthy

School of Computing: Conference and Workshop Papers

As more reliance is placed on computing and networking systems, the need for redundancy increases. The Common Address Redundancy Protocol (CARP) protocol and OpenBSD’s pfsync utility provide a means by which to implement redundant routers and firewalls. This paper details how CARP and pfsync work together to provide this redundancy and explores the performance one can expect from the open source solutions. Two experiments were run: one showing the relationship between firewall state creation and state synchronization traffic and the other showing how TCP sessions are transparently maintained in the event of a router failure. Discussion of these simulations along …

Autonomous Clustering-Based Heterogeneous Waveband Switching In Wdm Networks, Mengke Li, Byrav Ramamurthy

School of Computing: Conference and Workshop Papers

Employing waveband switching (WBS) in WDM networks can reduce the network operational cost and the call blocking probability. However, upgrading the existing optical switching architecture requires time and money. It is expected that a heterogeneous waveband switching (HeteroWBS) architecture would be desirable, where some nodes can support WBS functions and some cannot. We study the performance of HeteroWBS networks in terms of call blocking probability and cost savings under dynamic traffic requests. We propose an autonomous clustering-based HeteroWBS (AS-HeteroWBS) architecture to clusters the network into multiple autonomous systems (ASs). An AS may contain some specific nodes that provide WBS functions …

Integrated Intermediate Waveband And Wavelength Switching For Optical Wdm Mesh Networks, Mengke Li, Byrav Ramamurthy

School of Computing: Conference and Workshop Papers

As wavelength-division multiplexing (WDM) evolves towards practical applications in optical transport networks, waveband switching (WBS) has been introduced to cut down the operational costs and to reduce the complexities and sizes of network components, e.g., optical cross-connects (OXCs). This paper considers the routing, wavelength assignment and waveband assignment (RWWBA) problem in a WDM network supporting mixed waveband and wavelength switching. First, the techniques supporting waveband switching are studied, where a node architecture enabling mixed waveband and wavelength switching is proposed. Second, to solve the RWWBA problem with reduced switching costs and improved network throughput, the cost savings and call blocking …

Dynamic Lightpath Scheduling In Next-Generation Wdm Optical Networks, Lu Shen, Ajay Todimala, Byrav Ramamurthy, Xi Yang

School of Computing: Conference and Workshop Papers

Lightpath scheduling is an important capability in next-generation wavelength-division multiplexing (WDM) optical networks to reserve resources in advance for a specified time period while provisioning end-to-end lightpaths. In this study, we propose an approach to support dynamic lightpath scheduling in such networks. To minimize blocking probability in a network that accommodates dynamic scheduled lightpath demands (DSLDs), resource allocation should be optimized in a dynamic manner. However, for the network users who desire deterministic services, resources must be reserved in advance and guaranteed for future use. These two objectives may be mutually incompatible. Therefore, we propose a two-phase dynamic lightpath scheduling …

A Survey Of Security Issues In Wireless Sensor Networks, Yong Wang, Garhan Attebury, Byrav Ramamurthy

School of Computing: Faculty Publications

Wireless Sensor Networks (WSNs) are used in many applications in military, ecological, and health-related areas. These applications often include the monitoring of sensitive information such as enemy movement on the battlefield or the location of personnel in a building. Security is therefore important in WSNs. However, WSNs suffer from many constraints, including low computation capability, small memory, limited energy resources, susceptibility to physical capture, and the use of insecure wireless communication channels. These constraints make security in WSNs a challenge. In this article we present a survey of security issues in WSNs. First we outline the constraints, security requirements, and …

The Performance Of Elliptic Curve Based Group Diffie-Hellman Protocols For Secure Group Communication Over Ad Hoc Networks, Yong Wang, Byrav Ramamurthy, Xukai Zou

School of Computing: Conference and Workshop Papers

The security of the two party Diffie-Hellman key exchange protocol is currently based on the discrete logarithm problem (DLP). However, it can also be built upon the elliptic curve discrete logarithm problem (ECDLP). Most proposed secure group communication schemes employ the DLP-based Diffie-Hellman protocol. This paper proposes the ECDLP-based Diffie-Hellman protocols for secure group communication and evaluates their performance on wireless ad hoc networks. The proposed schemes are compared at the same security level with DLP-based group protocols under different channel conditions. Our experiments and analysis show that the Tree-based Group Elliptic Curve Diffie-Hellman (TGECDH) protocol is the best in …

Spatial Correlation-Based Collaborative Medium Access Control In Wireless Sensor Networks, Mehmet C. Vuran, Ian F. Akyildiz

School of Computing: Faculty Publications

Wireless Sensor Networks (WSN) are mainly characterized by dense deployment of sensor nodes which collectively transmit information about sensed events to the sink. Due to the spatial correlation between sensor nodes subject to observed events, it may not be necessary for every sensor node to transmit its data. This paper shows how the spatial correlation can be exploited on the Medium Access Control (MAC) layer. To the best of our knowledge, this is the first effort which exploits spatial correlation in WSN on the MAC layer. A theoretical framework is developed for transmission regulation of sensor nodes under a distortion …

Eraid: Conserving Energy In High Performance Raid Systems With Conventional Disks, Dong Li, Jun Wang

School of Computing: Technical Reports

Recently energy consumption becomes an ever critical concern for both low-end and high-end storage server and data centers. A majority of existing energy conservation solutions resort to multi-speed disks. However, current server systems are still built with conventional disks.
In this paper, we propose an energy saving policy, eRAID, for conventional disk based RAID-1 systems. eRAID saves energy by spinning down partial or entire mirror disk group with predictable performance degradation. The heart work of eRAID is to develop an accurate dynamic performance control (including disk power management) scheme. To guarantee service quality, the dynamic performance control works for two …

Helping End-User Programmers “Engineer” Dependable Software, Gregg Rothermel

School of Computing: Conference and Workshop Papers

Not long ago, most software was written by professional programmers, who could be presumed to have an interest in software engineering methodologies and in tools and techniques for improving software dependability. Today, however, a great deal of software is written not by professionals but by end-users, who create applications such as multimedia simulations, dynamic web pages, and spreadsheets. Applications such as these are often used to guide important decisions or aid in important tasks, and it is important that they be sufficiently dependable, but evidence shows that they frequently are not. For example, studies have shown that a large percentage …

Spatio-Temporal Characteristics Of Point And Field Sources In Wireless Sensor Networks, Mehmet C. Vuran, Ӧzgür B. Akan

School of Computing: Conference and Workshop Papers

Wireless Sensor Networks (WSN) are comprised of densely deployed sensor nodes collaboratively observing and communicating extracted information about a physical phenomenon. Dense deployment of sensor nodes makes the sensor observations highly correlated in the space domain. In addition, consecutive samples obtained by a sensor node are also temporally correlated for the applications involving the observation of the variation of a physical phenomenon. Based on the physical characteristics and dispersion pattern over the area, the phenomenon to be observed can be modeled as point source or field source. Clearly, understanding the spatio-temporal correlation characteristics of the point and field sources brings …

A Cross-Layer Protocol For Wireless Sensor Networks, Ian F. Akyildiz, Mehmet C. Vuran, Ӧzgür B. Akan

School of Computing: Conference and Workshop Papers

Severe energy constraints of battery-powered sensor nodes necessitate energy-efficient communication protocols in order to fulfill application objectives of wireless sensor networks (WSN). However, the vast majority of the existing solutions are based on classical layered protocols approach. It is much more resource-efficient to have a unified scheme which melts common protocol layer functionalities into a cross-layer module for resource-constrained sensor nodes. To the best of our knowledge, to date, there is no unified cross-layer communication protocol for efficient and reliable event communication which considers transport, routing, medium access functionalities with physical layer (wireless channel) effects for WSNs.
In this paper, …

Cross-Layer Analysis Of Error Control In Wireless Sensor Networks, Mehmet C. Vuran, Ian F. Akyildiz

School of Computing: Conference and Workshop Papers

Severe energy constraints and hence the low power communication requirements amplify the significance of the energy efficient and preferably cross-layer error control mechanisms in Wireless Sensor Networks (WSN). In this paper, a crosslayer methodology for the analysis of error control schemes in WSNs is presented such that the effects of multi-hop routing and the broadcast nature of the wireless channel are investigated. More specifically, the cross-layer effects of routing, medium access and physical layers are considered. This analysis enables a comprehensive comparison of forward error correction (FEC) and automatic repeat request (ARQ) in WSNs.
FEC schemes improve the error resiliency …

A Constraint-Based Approach To Solving Minesweeper, Ken Bayer, Josh Snyder, Berthe Y. Choueiry

School of Computing: Conference and Workshop Papers

·Motivate the students for the study of Constraint Processing (CP). Minesweeper is perfect to this end because it allows us to illustrate the use of CP algorithms in a familiar context and show how they operate.

·Understand and demystify humans’ fascination with puzzles.

·Discourage graduate students from losing too much time playing the game by making a program that plays the game for them.

Burrows Dug By Large Vertebrates Into Rain-Moistened Middle Jurassic Sand Dunes, David B. Loope

Department of Earth and Atmospheric Sciences: Faculty Publications

In south-central Utah, eolian cross-strata of the Escalante Member of the Entrada Sandstone contain inclined, cylindrical burrows up to 63 cm in diameter and 305 cm long. Of the 14 large tunnels located during this study, 12 descend from second- and third-order bounding surfaces that formed on the lee slopes of large dune ridges, well above the water table. The tunnels are inclined 15°–22°; one tunnel ends in an expanded chamber. Eolian cross-strata fill proximal portions of four of the tunnels and indicate that after abandonment, sand drifts migrated as much as a meter into the open shafts. Structureless sand …

The Earth All Around Us: Selected Building Stone In Lincoln, Nebraska. A Walking Tour, William J. Wayne

Department of Earth and Atmospheric Sciences: Faculty Publications

Stone has been a primary building material for millennia. Cities, therefore, are treasure troves of earth materials. A wide variety of stones from many places are used for walls, as foundations to support entire buildings, as trim, and more recently as cladding (facing, an overlay). The Earth science teacher can find, in the limited space of an urban environment, a superb collection of stones with which to introduce students to these materials. The surfaces of stones on the outsides of buildings illustrate the durability and the vulnerability of each kind of stone to the local climate. And the history of …

Understanding Farmers’ Forecast Use From Their Beliefs, Values, Social Norms, And Perceived Obstacles*, Q. Steven Hu, Lisa M. Pytlikzillig, Gary D. Lynne, Alan Tomkins, William J. Waltman, Michael J. Hayes, Kenneth Hubbard, Ikrom Artikov, Stacey Hoffman, Donald A. Wilhite

Department of Earth and Atmospheric Sciences: Faculty Publications

Although the accuracy of weather and climate forecasts is continuously improving and new information retrieved from climate data is adding to the understanding of climate variation, use of the forecasts and climate information by farmers in farming decisions has changed little. This lack of change may result from knowledge barriers and psychological, social, and economic factors that undermine farmer motivation to use forecasts and climate information. According to the theory of planned behavior (TPB), the motivation to use forecasts may arise from personal attitudes, social norms, and perceived control or ability to use forecasts in specific decisions. These attributes are …