3,103 research outputs found
Bringing nature back into cities: urban land environments, indigenous cover and urban restoration
1. The restoration of urban ecosystems is an increasingly important strategy to maintain and enhance indigenous biodiversity as well as reconnecting people to the environment. High levels of endemism, the sensitivity of species that have evolved without humans, and the invasion of exotic species have all contributed to severe depletion of indigenous biodiversity in New Zealand. In this work, we analysed national patterns of urban biodiversity in New Zealand and the contribution that urban restoration can make to maximising and enhancing indigenous biodiversity.
2. We analysed data from two national databases in relation to the 20 largest New Zealand cities. We quantified existing indigenous biodiversity within cities, both within the core built up matrix and in centroid buffer zones of 5, 10 and 20 km around this urban centre. We analysed the type and frequency of land environments underlying cities as indicators of the range of native ecosystems that are (or can potentially be) represented within the broader environmental profile of New Zealand. We identified acutely threatened land environments that are represented within urban and periurban areas and the potential role of cities in enhancing biodiversity from these land environments.
3. New Zealand cities are highly variable in both landform and level of indigenous resource. Thirteen of 20 major land environments in New Zealand are represented in cities, and nearly three-quarters of all acutely threatened land environments are represented within 20 km of city cores nationally. Indigenous land cover is low within urban cores, with less than 2% on average remaining, and fragmentation is high. However, indigenous cover increases to more than 10% on average in the periurban zone, and the size of indigenous remnants also increases. The number of remaining indigenous landcover types also increases from only 5 types within the urban centre, to 14 types within 20 km of the inner urban cores.
4. In New Zealand, ecosystem restoration alone is not enough to prevent biodiversity loss from urban environments, with remnant indigenous cover in the urban core too small (and currently too degraded) to support biodiversity long-term. For some cities, indigenous cover in the periurban zone is also extremely low. This has significant ramifications for the threatened lowland and coastal environments that are most commonly represented in cities. Reconstruction of ecosystems is required to achieve a target of 10% indigenous cover in cities: the addition of land to land banks for this purpose is crucial. Future planning that protects indigenous remnants within the periurban zone is critical to the survival of many species within urban areas, mitigating the homogenisation and depletion of indigenous flora and fauna typical of urbanisation. A national urban biodiversity plan would help city councils address biodiversity issues beyond a local and regional focus, while encouraging predominantly local solutions to restoration challenges, based on the highly variable land environments, ecosystems and patch connectivity present within different urban areas
Model for quantitative tip-enhanced spectroscopy and the extraction of nanoscale-resolved optical constants
Near-field infrared spectroscopy by elastic scattering of light from a probe
tip resolves optical contrasts in materials at dramatically sub-wavelength
scales across a broad energy range, with the demonstrated capacity for chemical
identification at the nanoscale. However, current models of probe-sample
near-field interactions still cannot provide a sufficiently quantitatively
interpretation of measured near-field contrasts, especially in the case of
materials supporting strong surface phonons. We present a model of near-field
spectroscopy derived from basic principles and verified by finite-element
simulations, demonstrating superb predictive agreement both with tunable
quantum cascade laser near-field spectroscopy of SiO thin films and with
newly presented nanoscale Fourier transform infrared (nanoFTIR) spectroscopy of
crystalline SiC. We discuss the role of probe geometry, field retardation, and
surface mode dispersion in shaping the measured near-field response. This
treatment enables a route to quantitatively determine nano-resolved optical
constants, as we demonstrate by inverting newly presented nanoFTIR spectra of
an SiO thin film into the frequency dependent dielectric function of its
mid-infrared optical phonon. Our formalism further enables tip-enhanced
spectroscopy as a potent diagnostic tool for quantitative nano-scale
spectroscopy.Comment: 19 pages, 9 figure
Estimating age of spotted and spinner dolphins (Stenella attenuata and Stenella longirostris) from teeth
This paper is an account of preparation and examination techniques and criteria used to estimate age in decalcified and stained tooth thin sections from spinner and spotted dolphins. A dentinal growth layer group (GLG),
composed of two thin light and two thicker dark-stained layers, is deposited annually. The GLG component layers are variably visible, but the "ideal" pattern and successive thinning of dentinal GLGs are used as a guide to determine GLG limits. Age-specific thicknesses of dentinal GLGs found in Hawaiian spinner dolphin teeth seem to be applicable to teeth of spotted dolphins and can be used as an aid in locating GLG boundaries. Cementa1 GLGs are composed of a dark-stained and alightly stained layer and usually are
deposited at a rate of one per year, but may be deposited every other year or two or three times per year. Two slightly different methods of counting dentinal GLGs are presented, along with guidelines for determining whether
dentinal or cementa1 GLG counts provide the best estimate of age for a specimen. (PDF contains 23 pages.
DDR2 controls breast tumor stiffness and metastasis by regulating integrin mediated mechanotransduction in CAFs
Biomechanical changes in the tumor microenvironment influence tumor progression and metastases. Collagen content and fiber organization within the tumor stroma are major contributors to biomechanical changes (e., tumor stiffness) and correlated with tumor aggressiveness and outcome. What signals and in what cells control collagen organization within the tumors, and how, is not fully understood. We show in mouse breast tumors that the action of the collagen receptor DDR2 in CAFs controls tumor stiffness by reorganizing collagen fibers specifically at the tumor-stromal boundary. These changes were associated with lung metastases. The action of DDR2 in mouse and human CAFs, and tumors in vivo, was found to influence mechanotransduction by controlling full collagen-binding integrin activation via Rap1-mediated Talin1 and Kindlin2 recruitment. The action of DDR2 in tumor CAFs is thus critical for remodeling collagen fibers at the tumor-stromal boundary to generate a physically permissive tumor microenvironment for tumor cell invasion and metastases
Implementation Performance of Mobile Wimax for Various Propagation Models
Nowadays the Worldwide Interoperability of Microwave Access (WiMAX) technology becomes popular and receives growing acceptance as a Broadband Wireless Access (BWA) system. These networks enable high data transmission rates. WiMAX is the newest wireless broadband Internet technology based on IEEE 802.16 standard. Based on OFDM (Orthogonal Frequency Division Multiplexing), this system uses radio frequency range from 2 to 11 GHz. WiMAX has potential success in its line-of-sight (LOS) and non line-of-sight (NLOS) conditions which operating below 11 GHz frequency. There are going to be a surge all over the world for the deployment of WiMAX networks. Estimation of path loss and signal coverage is very important in initial deployment of wireless network and cell planning. Numerous path loss (PL) models (e.g. Okumura Model, Hata Model) are available to predict the propagation loss, but they are inclined to be limited to the lower frequency bands (up to 2 GHz). In this thesis we compare and analyze different path loss models and signal coverage (i.e. COST 231 Hata model, ECC-33 model, SUI model, Ericsson model and COST 231 Walfish-Ikegami model) in different receiver antenna heights in urban, suburban and rural environments in NLOS condition. Our main concentration in this thesis is to find out a suitable model for different environments to provide guidelines for cell planning of WiMAX at cellular frequency.
From calculations, that I made, can be concluded, that FSPL model, gives the lowest path loss, in all type of terrains – rural, suburban and rural areas. Model ECC-33 can predict path loss in urban and suburban areas, but it is unusable in rural areas. Also I can conclude, that model SUI, has approximately the same values of path loss with those, computed with FSPL model. My research shows that all Pathloss will be less in Rural areas compared to urban and suburban, Signal coverage will be more in suburban areas than in urban areas
Time-separated entangled light pulses from a single-atom emitter
The controlled interaction between a single, trapped, laser-driven atom and
the mode of a high-finesse optical cavity allows for the generation of
temporally separated, entangled light pulses. Entanglement between the
photon-number fluctuations of the pulses is created and mediated via the atomic
center-of-mass motion, which is interfaced with light through the mechanical
effect of atom-photon interaction. By means of a quantum noise analysis we
determine the correlation matrix which characterizes the entanglement, as a
function of the system parameters. The scheme is feasible in experimentally
accessible parameter regimes. It may be easily extended to the generation of
entangled pulses at different frequencies, even at vastly different
wavelengths.Comment: 17 pages, 5 figures. Modified version, to appear in the New Journal
of Physic
Coping styles in patients with haematological cancer in a Malaysian hospital.
OBJECTIVE: To assess coping styles of haematological cancer patients and investigate factors (major depressive disorders, socio-demographic profiles and clinical factors) that influence them.
METHODS:This was a cross-sectional study conducted at the Ampang Hospital in Kuala Lumpur, Malaysia, which is a tertiary referral centre for haematological diseases. In all, 105 patients with haematological cancer were assessed using the Brief COPE questionnaire to examine the coping styles of patients, and the Mini-International Neuropsychiatric Interview to assess major depressive disorder.
RESULTS:The response rate was 83%. The coping strategies used by haematological cancer patients in descending order of frequency were: behavioural disengagement, active coping, denial, venting, self-distraction, substance use, acceptance, humour, use of emotional support, use of instrumental support, religion, positive reframing, planning, and self-blame. The coping styles were found to be associated with major depressive disorder, socio-demographic profiles, and clinical factors. Self-distraction and positive reframing coping styles were significant predictors and related to major depressive disorder.
CONCLUSION:The early identification of poor coping styles in cancer patients is important, in order to enhance their survival and prevent relapses
Cell Kinetic Basis for Pathophysiology of Psoriasis
Studies on the cell proliferation kinetics of psoriatic epidermal cells are presented and the results compared to similar studies for normal epidermis. The short 36-h duration of the psoriatic cell cycle (Tc) is confirmed with the first double-peaked fraction of labeled mitoses (FLM) curve in human subjects. The growth fraction of psoriasis using two experimental techniques approximates 100% within 36 h, confirming the rapid Tc found by the FLM method. The cell kinetic basis for the pathophysiology of psoriasis consists of at least 3 proliferative abnormalities in comparison to normal epidermis. By far the largest alteration is the shortening of the Tc from 311 to 36 h. There is also a doubling of the proliferative cell population in psoriasis from 27,000 to 52,000 cells/mm and an increase in the growth fraction from 60% to 100%. As a consequence of these abnormalities the psoriatic epidermis produces 35,000 cells/day from a proliferative compartment of 52,000 cells/mm2 surface area. This is a 28-fold greater production of cells than the 1,246 cells/day produced in normal epidermis. The biochemical or control factors leading to these kinetic differences continue to remain elusive
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