Edge effects and the impact of wildfires on populations of small non-volant mammals in the forest-savanna transition zone in Southern Amazonia

O efeito de borda e do fogo sobre a comunidade de pequenos mamíferos não-voadores foi investigada em uma área de transição entre Cerrado e Floresta em uma área de matriz de soja na Amazônia Oriental. Os indivíduos foram coletados em 24 transectos, dos quais 16 foram distribuídos em área sem efeito do fogo e oito distribuídos com efeito do fogo. Um total de 11 espécies foi registrado, incluindo seis roedores e cinco marsupiais. A espécie Hylaeamys megacephalus foi a mais abundante em áreas sem efeito do fogo. A abundância e riqueza de pequenos mamíferos não-voadores apresentaram uma diminuição em áreas queimadas, entretanto o efeito do fogo parece mascarar o efeito de borda nestas mesmas áreas. Em relação ao efeito de borda, sem nenhum efeito de fogo, a relação entre a abundância de pequenos mamíferos não-voadores com a distância da borda foi positiva. A relação entre a diversidade de pequenos mamíferos e efeito de borda pode ser ligada à vegetação matriz e características ecológicas de cada espécie.

Patch size, shape and edge distance influences seed predation in a keystone palm in tropical rainforests

Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

Host-specificity and morphometrics of female Haemonchus contortus, H. placei and H. similis (Nematoda: Trichostrongylidae) in cattle and sheep from shared pastures in Sao Paulo State, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Soft edge of hadron scattering and minijet models for the total and inelastic pp cross sections at LHC and beyond

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Titanium K-edge XAS study on local structure of Pb1-xCaxTiO3 ferroelectric ceramics

In order to characterize the local structure of Pb1-xCaxTiO3 (PCT) samples, Ti K-edge XANES measurements were performed and showed that Ca incorporation to PbTiO3 structure leads to a decreasing of local distortion of Ti atoms in relation to oxygen atoms at the TiO6 octahedra. Moreover, according to EXAFS measurements, the local structure around Ti atoms exhibits tetragonal symmetry with P4mm space group for samples with x <= 0.475, whereas orthorhombic symmetry with Pbnm space group was observed for x equals to 0.50 and 0.55.

Shared Escovopsis parasites between leaf-cutting and non-leaf-cutting ants in the higher attine fungus-growing ant symbiosis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Shared Feed as a Means of Deer-to-Deer Transmission of Mycobacterium bovis

To determine the ability of experimentally inoculated white-tailed deer (Odocoileus virginianus) to transmit Mycobacterium bovis to naive deer through the sharing of feed, four deer were intratonsillarly inoculated with 4x105 colony-forming units of M. bovis. On a daily basis, feed not consumed by inoculated deer after approximately 8 hr was offered to four naıve deer maintained in a separate pen, where direct contact, aerosol transmission, or transmission through personnel were prevented. After 150 days, naıve deer were euthanized and examined. All naıve deer had lesions consistent with tuberculosis and M. bovis was isolated from various tissues. The most commonly affected tissues were lung, tracheobronchial lymph nodes, and mediastinal lymph nodes. This study demonstrates the potential for indirect transmission of M. bovis through the sharing of feed. Intentional or unintentional feeding of deer by wildlife or agricultural interests in regions where M. bovis infection is endemic should be avoided because both direct and indirect transmission through sharing of feed are enhanced.

Survivable Lightpath Provisioning in WDM Mesh Networks Under Shared Path Protection and Signal Quality Constraints

This paper addresses the problem of survivable lightpath provisioning in wavelength-division-multiplexing (WDM) mesh networks, taking into consideration optical-layer protection and some realistic optical signal quality constraints. The investigated networks use sparsely placed optical–electrical–optical (O/E/O) modules for regeneration and wavelength conversion. Given a fixed network topology with a number of sparsely placed O/E/O modules and a set of connection requests, a pair of link-disjoint lightpaths is established for each connection. Due to physical impairments and wavelength continuity, both the working and protection lightpaths need to be regenerated at some intermediate nodes to overcome signal quality degradation and wavelength contention. In the present paper, resource-efficient provisioning solutions are achieved with the objective of maximizing resource sharing. The authors propose a resource-sharing scheme that supports three kinds of resource-sharing scenarios, including a conventional wavelength-link sharing scenario, which shares wavelength links between protection lightpaths, and two new scenarios, which share O/E/O modules between protection lightpaths and between working and protection lightpaths. An integer linear programming (ILP)-based solution approach is used to find optimal solutions. The authors also propose a local optimization heuristic approach and a tabu search heuristic approach to solve this problem for real-world, large mesh networks. Numerical results show that our solution approaches work well under a variety of network settings and achieves a high level of resource-sharing rates (over 60% for O/E/O modules and over 30% for wavelength links), which translate into great savings in network costs.

A load-balancing spare capacity reallocation approach in service-rich SONET metro mesh networks

The next-generation SONET metro network is evolving into a service-rich infrastructure. At the edge of such a network, multi-service provisioning platforms (MSPPs) provide efficient data mapping enabled by Generic Framing Procedure (GFP) and Virtual Concatenation (VC). The core of the network tends to be a meshed architecture equipped with Multi-Service Switches (MSSs). In the context of these emerging technologies, we propose a load-balancing spare capacity reallocation approach to improve network utilization in the next-generation SONET metro networks. Using our approach, carriers can postpone network upgrades, resulting in increased revenue with reduced capital expenditures (CAPEX). For the first time, we consider the spare capacity reallocation problem from a capacity upgrade and network planning perspective. Our approach can operate in the context of shared-path protection (with backup multiplexing) because it reallocates spare capacity without disrupting working services. Unlike previous spare capacity reallocation approaches which aim at minimizing total spare capacity, our load-balancing approach minimizes the network load vector (NLV), which is a novel metric that reflects the network load distribution. Because NLV takes into consideration both uniform and non-uniform link capacity distribution, our approach can benefit both uniform and non-uniform networks. We develop a greedy loadbalancing spare capacity reallocation (GLB-SCR) heuristic algorithm to implement this approach. Our experimental results show that GLB-SCR outperforms a previously proposed algorithm (SSR) in terms of established connection capacity and total network capacity in both uniform and non-uniform networks.

A Load-Balancing Shared-Protection-Path Reconfiguration Approach in WDM Wavelength-Routed Networks

Wavelength-routed networks (WRN) are very promising candidates for next-generation Internet and telecommunication backbones. In such a network, optical-layer protection is of paramount importance due to the risk of losing large amounts of data under a failure. To protect the network against this risk, service providers usually provide a pair of risk-independent working and protection paths for each optical connection. However, the investment made for the optical-layer protection increases network cost. To reduce the capital expenditure, service providers need to efficiently utilize their network resources. Among all the existing approaches, shared-path protection has proven to be practical and cost-efficient [1]. In shared-path protection, several protection paths can share a wavelength on a fiber link if their working paths are risk-independent. In real-world networks, provisioning is usually implemented without the knowledge of future network resource utilization status. As the network changes with the addition and deletion of connections, the network utilization will become sub-optimal. Reconfiguration, which is referred to as the method of re-provisioning the existing connections, is an attractive solution to fill in the gap between the current network utilization and its optimal value [2]. In this paper, we propose a new shared-protection-path reconfiguration approach. Unlike some of previous reconfiguration approaches that alter the working paths, our approach only changes protection paths, and hence does not interfere with the ongoing services on the working paths, and is therefore risk-free. Previous studies have verified the benefits arising from the reconfiguration of existing connections [2] [3] [4]. Most of them are aimed at minimizing the total used wavelength-links or ports. However, this objective does not directly relate to cost saving because minimizing the total network resource consumption does not necessarily maximize the capability of accommodating future connections. As a result, service providers may still need to pay for early network upgrades. Alternatively, our proposed shared-protection-path reconfiguration approach is based on a load-balancing objective, which minimizes the network load distribution vector (LDV, see Section 2). This new objective is designed to postpone network upgrades, thus bringing extra cost savings to service providers. In other words, by using the new objective, service providers can establish as many connections as possible before network upgrades, resulting in increased revenue. We develop a heuristic load-balancing (LB) reconfiguration approach based on this new objective and compare its performance with an approach previously introduced in [2] and [4], whose objective is minimizing the total network resource consumption.

A Heuristic with Bounded Guarantee to Compute Diverse Paths under Shared Protection in WDM Mesh Networks

Establishing a fault-tolerant connection in a network involves computation of diverse working and protection paths. The Shared Risk Link Group (SRLG) [1] concept is used to model several types of failure conditions such as link, node, fiber conduit, etc. In this work we focus on the problem of computing optimal SRLG/link diverse paths under shared protection. Shared protection technique improves network resource utilization by allowing protection paths of multiple connections to share resources. In this work we propose an iterative heuristic for computing SRLG/link diverse paths. We present a method to calculate a quantitative measure that provides a bounded guarantee on the optimality of the diverse paths computed by the heuristic. The experimental results on computing link diverse paths show that our proposed heuristic is efficient in terms of number of iterations required (time taken) to compute diverse paths when compared to other previously proposed heuristics.

Survivable Virtual Topology Routing under Shared Risk Link Groups in WDM Networks

Network survivability is one of the most important issues in the design of optical WDM networks. In this work we study the problem of survivable routing of a virtual topology on a physical topology with Shared Risk Link Groups (SRLG). The survivable virtual topology routing problem against single-link failures in the physical topology is proved to be NP-complete in [1]. We prove that survivable virtual topology routing problem against SRLG/node failures is also NP-complete. We present an improved integer linear programming (ILP) formulation (in comparison to [1]) for computing the survivable routing under SRLG/node failures. Using an ILP solver, we computed the survivable virtual topology routing against link and SRLG failures for small and medium sized networks efficiently. As even our improved ILP formulation becomes intractable for large networks, we present a congestion-based heuristic and a tabu search heuristic (which uses the congestion-based heuristic solution as the initial solution) for computing survivable routing of a virtual topology. Our experimental results show that tabu search heuristic coupled with the congestion based heuristic (used as initial solution) provides fast and near-optimal solutions.

Evaluating the EDGE: What are the Impacts?

In 2008, the Center for Applied Rural Innovation conducted a comprehensive five-year evaluative study of the NebraskaEDGE program. Two different surveys were sent to former NebraskaEDGE training participants who were enrolled in the EDGE training courses between the Fall of 2002 and Spring of 2007. The objective of the surveys were to: 1) measure changes in participant knowledge and skills as a result of the entrepreneurial training class, and 2) better learn how participants applied their new skills to their businesses and what those impacts were on the businesses.

Evidence that a single bioluminescent system is shared by all known bioluminescent fungal lineages

Since the early 20th century, many researchers have attempted to determine how fungi are able to emit light. The first successful experiment was obtained using the classical luciferin-luciferase test that consists of mixing under controlled conditions hot (substrate/luciferin) and cold (enzyme/luciferase) water extracts prepared from bioluminescent fungi. Failures by other researchers to reproduce those experiments using different species of fungi lead to the hypothesis of a non-enzymatic luminescent pathway. Only recently, the involvement of a luciferase in this system was proven, thus confirming its enzymatic nature. Of the 100 000 described species in Kingdom Fungi, only 71 species are known to be luminescent and they are distributed unevenly amongst four distantly related lineages. The question we address is whether the mechanism of bioluminescence is the same in all four evolutionary lineages suggesting a single origin of luminescence in the Fungi, or whether each lineage has a unique mechanism for light emission implying independent origins. We prepared hot and cold extracts of numerous species representing the four bioluminescent fungal lineages and performed cross-reactions (luciferin x luciferase) in all possible combinations using closely related non-luminescent species as controls. All cross-reactions with extracts from luminescent species yielded positive results, independent of lineage, whereas no light was emitted in cross-reactions with extracts from non-luminescent species. These results support the hypothesis that all four lineages of luminescent fungi share the same type of luciferin and luciferase, that there is a single luminescent mechanism in the Fungi, and that fungal luciferin is not a ubiquitous molecule in fungal metabolism.

Comparative study on the far-field spectra and near-field amplitudes for silver and gold nanocubes irradiated at 514, 633 and 785 nm as a function of the edge length

We describe a systematic investigation by the discrete dipole approximation on the optical properties of silver (Ag) and gold (Au) nanocubes as a function of the edge length in the 20-100 nm range. Our results showed that, as the nanocube size increased, the plasmon resonance modes shifted to higher wavelengths, the contribution from scattering to the extinction increased, and the quadrupole modes became more intense in the spectra. The electric field amplitudes at the surface of the nanocubes were calculated considering 514, 633 and 785 nm as the excitation wavelengths. While Ag nanocubes displayed the highest electric field amplitudes (vertical bar E vertical bar(max)) when excited at 514 nm, the Au nanocubes displayed higher vertical bar E vertical bar(max) values than Ag, for all sizes investigated, when the excitation wavelength was either 633 or 785 nm. The variations in vertical bar E vertical bar(max) as a function of size for both Ag and Au nanocubes could be explained based on the relative position of the surface plasmon resonance peak relative to the wavelength of the incoming electromagnetic wave. Our results show that not only size and composition, but also the excitation wavelength, can play an important role over the maximum near-field amplitudes values generated at the surface of the nanocubes.