旅游相关活动对九寨沟核心景区植物多样性与结构的影响

日益增强的旅游活动干扰正成为九寨沟世界自然遗产的有效保护与持续管理不可回避的挑战，已成为当前区域生态保护与经济发展的焦点问题之一。阐明相关旅游的干扰活动对核心景区植物物种组成、多样性与结构的影响是九寨沟有效保护与持续管理的必要前提和基础，然而至今少有研究。选择九寨沟与旅游活动相关的九个景点、公路建设地段以及退耕地还林地，详细调查了林下植被结构、物种组成与多样性，比较了相关旅游活动干扰与基本未受干扰地段的差异。目的是阐明九寨沟核心景区旅游干扰条件下植物多样性与群落结构及其特点，揭示旅游干扰与植被结构和生物多样的相互关系，评估九寨沟旅游管理的有效性，探索减免旅游干扰影响的对策与措施。初步结论如下。 1.旅游活动引起九寨沟核心景区植物组成和群落结构特征改变显著。栈道及公路附近许多耐荫喜湿的敏感种局部消失，而早熟禾、车前草、委陵菜等耐干旱、耐践踏、繁殖能力强的植物种群扩大；外来物种频繁出现并已少量侵入干扰相对较轻的林分深处；林下群落以草本植物为优势，灌木与苔藓植物的频度、盖度、高度以及灌木密度均有所下降。可见，大量的游人活动和景区公路建设已对九寨沟丰富的乡土植物构成极大威胁，导致其生物多样性降低。而九寨沟农耕地退耕有利于九寨沟生态环境和生物多样性保护，正逐步向稳定群落演替。 2．干扰强度的差异导致九寨沟植物所受影响的程度不同。栈道附近植物受影响的程度与游人活动频率有关，活动频率高的地段干扰强度大，对植物的影响程度重，反之植物所受的影响较轻。强度干扰地段，耐荫喜湿的物种少见，伴生植物优势地位突出，生物多样性明显降低，植物群落结构特征改变也极为显著；干扰较轻的地段，伴生物种少量出现，植物群落结构变化不明显，生物多样性略为降低，部分地区结构参数值和多样性指数有所升高。公路修建是一种强度干扰，它导致附近植物种类极为单一，草本优势种异常突出，多数植物生活力低下、生长更新能力差。 3.不同植物类群受干扰影响的程度不同。草本及苔藓植物的种类组成和多样性指数受干扰影响较大，灌木和苔藓植物的结构受干扰影响较大，苔藓植物对干扰影响最为敏感。 综合分析表明，九寨沟核心景区的管理虽然比较规范，但目前核心区热点景点段的管理仍然不够，旅游活动驱动了林下植被退化明显、物种组成显著变化、生物多样性衰退、非乡土喜光耐旱种群扩大。导致九寨沟核心区旅游活动与生物多样性保护目标尖锐冲突，进一步约束旅游活动带来的干扰，强化管理，开展林下植被恢复与非乡土喜光耐旱种群调控是九寨沟自然遗产地保护一项紧迫任务。 The increasing tourism disturbance is an unavoidable challenge to effective conservation and sustained tourist management of Jiuzhaigou Nature Reserve. It has become one of the focal problems of regional ecological protect and economic development. It is important to clarify effects of tourism disturbance on plant species composition, diversity and community structure in kernel spot for effective conservation and sustained tourist management in Jiuzhaigou, China. However, there were little studies about this yet. The study investigated the vegetation structure, species composition and diversity at nine sight spot, road area and four abandoned farmlands connecting with tourism, and compared the differences between disturbed area and undisturbed area. The purpose of the this study is clarifying the plant diversity and community structure and characteristics of the disturbed area in kernel spot of Jiuzhaigou, discovering the relation between vegetation structure and biodiversity, evaluating the effect of tourist management and exploring the measure decreasing tourist disturbance. Our results are following: 1. Tourism disturbance caused a significant change in species composition and structure of plant communities in kernel Spot of Jiuzhaigou. In the vicinity of plank and road, some native shade-tolerant or hygrophilous plants had disappeared, accompanying with the population expansion of some xerophilous and disturbance-resisting species such as Poa sp. Plantago depressa, Potentiila multicaulis and some exotic and synanthropic species. Herbs were domaint species, while frequency coverage and height of shrubs and bryophytes, and shrub density decreased. In indicated that tourist activities and build of road had adversely affected on native plant species, and led to decline in biodiversity of Jiuzhaigou Nature Reserve. Abandoned farmlands maybe conduced to entironment and biodiversity conservation. 2. Nearby the plank, influency variable of tourism disturbance on plant was alosely and positively correlated with disturbance intensity. There was companion plant species and lacked shape-loving species in heavy disturbed areas, which caused decrease in biodiversity and significant change in community structure in these places. On the contrary, in the slightly disturbed areas, some companion speices displayed and biodiversity decreased slightly, but no significant change in community structure in these areas. The biuld of road is a heavy disturbance form, which led to increase of herb species and to decrease in vitality and regeneration capacity. 3. The intensity of tourism disturbance on plant depended on plant groups. Tourism interference significantly influenced species composition and diversity index of herb and bryophyte; it also significantly influenced community structure; the bryophyte was more sensitive to tourism disturbance. Our result indicated that the management in kernel spot of Jiuzhaigou is relatively reasonable, but not adequate. Tourism speed the degradation of the vegetation under woodland, the change of the species composition, the decreaing of the biodiversity and the expanding of the exotic sunloving plant populations. The contradiction between tourism and conserving biodiversity is increasing, so enforcing management, regenerating the vegetation under woodland and adjusting the exotic sunloving arid-tolerent plant populations is a pressing work to protect the Jiuzhaigou natural legacy.

Millstone Hill电离层F层等效风场的气候学研究

Neutral winds and electric fields in the ionospheric F layer play important roles in the variations of the ionosphere, and also affect the thermospheric circulation via the close coupling between the ionosphere and the thermosphere. By now, the neutral winds and electric drifts are generally observed with ground-based Fabry-Perot interferometers (FPI) and incoherent scatter radars (ISR), rockets, and satellite-borne instrument. Based on the servo theory, the ionospheric equivalent winds, which include the information of both the neutral winds and electric fields, can be derived from these characteristic parameters observed by ionosondes. This indirect derivation has potential values in climatological researches and space weather forecast. With the data set of the incoherent scatter radar observations at Millstone Hill, USA, from 1976 to 2006, we statistically analyzed the climatological variations of the vertical component of the equivalent winds (VEWs) over Millstone Hill, which are derived from the ionospheric key parameters (the peak electron number density and peak height of the F2 layer, NmF2 and hmF2) on the basis of the servo theory, Liu's method, and measurements from the ion line-of-sight velocity as well. The main results of this analysis are summarized as follows: (1) The values of VEWs over Millstone Hill during nighttime are stronger than in the daytime, and the upward drift dominates most of the day. In 1993, Hagan found that the component of the neutral winds in the magnetic meridion in daytime is weaker than during nighttime under both solar maximum and minimum conditions; he also found that the equatorward winds dominate most of the day. Both results suggest that the thermosphere in Millstone Hill is modulated by the aurorally driven high-latitude circulation cell; that is, during geomagnetic quiet periods, the average auroral activity is strong enough to drive thermospheric circulation equatorward for most of the day at Millstone Hill. Moreover, since ion drag is the strongest during daytime when F region densities are enhanced by photoionization, the wind speeds are smaller during the daytime than in the nighttime. (2) There is equinoctial symmetry in VEWs at Millstone Hill. The amplitudes and phases of VEWs in spring are quite similar to those in autumn. In contrast, the nighttime upward drift in winter is weaker than in summer and the difference becomes more significant with increasing solar activity. This solstice asymmetry indicates that, the aurorally driven circulation in the northern hemisphere at Millstone Hill latitude is weaker in winter due to arctic darkness, because the subsolar point is in the southern hemisphere. (3) The comparison of the VEWs derived from three methods, i.e., the servo theory, Liu's method, and the ISR ion line-of-sight velocity measurements, indicates that the amplitudes and main phase tendencies of these VEWs accord well with each other during nighttime hours. However, the case in the daytime is relatively worse. This daytime discrepancy can be explained in terms of the effects of photochemical processes and the choices of the servo constants. A larger servo constant gives a stronger plasma drift in daytime. Therefore, this study tells how important to choose a suitable constant for deriving VEWs at Millstone Hill.

Large-scale structure of the fast solar wind

Breen, Andrew; Bisi, M.M.; Fallows, R.A.; Habbal, S.R., (2007) 'Large-scale structure of the fast solar wind', Journal of Geophysical Research 112(A6) pp.A06101 RAE2008

O prazer associado ao consumo de alimentos e factores influenciadores

Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Ciências Farmacêuticas

Experimental impulse radio IEEE 802.15.4a UWB based wireless sensor localization technology: Characterization, reliability and ranging

Ultra Wide Band (UWB) transmission has recently been the object of considerable attention in the field of next generation location aware wireless sensor networks. This is due to its fine time resolution, energy efficient and robustness to interference in harsh environments. This paper presents a thorough applied examination of prototype IEEE 802.15.4a impulse UWB transceiver technology to quantify the effect of line of sight (LOS) and non line of sight (NLOS) ranging in real indoor and outdoor environments. Results included draw on an extensive array of experiments that fully characterize the 802.15.4a UWB transceiver technology, its reliability and ranging capabilities for the first time. A new two way (TW) ranging protocol is proposed. The goal of this work is to validate the technology as a dependable wireless communications mechanism for the subset of sensor network localization applications where reliability and precision positions are key concerns.

Novel smart modules for imaging, communications, and displays

This dissertation proposes and demonstrates novel smart modules to solve challenging problems in the areas of imaging, communications, and displays. The smartness of the modules is due to their ability to be able to adapt to changes in operating environment and application using programmable devices, specifically, electronically variable focus lenses (ECVFLs) and digital micromirror devices (DMD). The proposed modules include imagers for laser characterization and general purpose imaging which smartly adapt to changes in irradiance, optical wireless communication systems which can adapt to the number of users and to changes in link length, and a smart laser projection display that smartly adjust the pixel size to achieve a high resolution projected image at each screen distance. The first part of the dissertation starts with the proposal of using an ECVFL to create a novel multimode laser beam characterizer for coherent light. This laser beam characterizer uses the ECVFL and a DMD so that no mechanical motion of optical components along the optical axis is required. This reduces the mechanical motion overhead that traditional laser beam characterizers have, making this laser beam characterizer more accurate and reliable. The smart laser beam characterizer is able to account for irradiance fluctuations in the source. Using image processing, the important parameters that describe multimode laser beam propagation have been successfully extracted for a multi-mode laser test source. Specifically, the laser beam analysis parameters measured are the M2 parameter, w0 the minimum beam waist, and zR the Rayleigh range. Next a general purpose incoherent light imager that has a high dynamic range (>100 dB) and automatically adjusts for variations in irradiance in the scene is proposed. Then a data efficient image sensor is demonstrated. The idea of this smart image sensor is to reduce the bandwidth needed for transmitting data from the sensor by only sending the information which is required for the specific application while discarding the unnecessary data. In this case, the imager demonstrated sends only information regarding the boundaries of objects in the image so that after transmission to a remote image viewing location, these boundaries can be used to map out objects in the original image. The second part of the dissertation proposes and demonstrates smart optical communications systems using ECVFLs. This starts with the proposal and demonstration of a zero propagation loss optical wireless link using visible light with experiments covering a 1 to 4 m range. By adjusting the focal length of the ECVFLs for this directed line-of-sight link (LOS) the laser beam propagation parameters are adjusted such that the maximum amount of transmitted optical power is captured by the receiver for each link length. This power budget saving enables a longer achievable link range, a better SNR/BER, or higher power efficiency since more received power means the transmitted power can be reduced. Afterwards, a smart dual mode optical wireless link is proposed and demonstrated using a laser and LED coupled to the ECVFL to provide for the first time features of high bandwidths and wide beam coverage. This optical wireless link combines the capabilities of smart directed LOS link from the previous section with a diffuse optical wireless link, thus achieving high data rates and robustness to blocking. The proposed smart system can switch from LOS mode to Diffuse mode when blocking occurs or operate in both modes simultaneously to accommodate multiple users and operate a high speed link if one of the users requires extra bandwidth. The last part of this section presents the design of fibre optic and free-space optical switches which use ECVFLs to deflect the beams to achieve switching operation. These switching modules can be used in the proposed optical wireless indoor network. The final section of the thesis presents a novel smart laser scanning display. The ECVFL is used to create the smallest beam spot size possible for the system designed at the distance of the screen. The smart laser scanning display increases the spatial resoluti on of the display for any given distance. A basic smart display operation has been tested for red light and a 4X improvement in pixel resolution for the image has been demonstrated.

The development of new methods for high resolution radio astronomy imaging

Very Long Baseline Interferometry (VLBI) polarisation observations of the relativistic jets from Active Galactic Nuclei (AGN) allow the magnetic field environment around the jet to be probed. In particular, multi-wavelength observations of AGN jets allow the creation of Faraday rotation measure maps which can be used to gain an insight into the magnetic field component of the jet along the line of sight. Recent polarisation and Faraday rotation measure maps of many AGN show possible evidence for the presence of helical magnetic fields. The detection of such evidence is highly dependent both on the resolution of the images and the quality of the error analysis and statistics used in the detection. This thesis focuses on the development of new methods for high resolution radio astronomy imaging in both of these areas. An implementation of the Maximum Entropy Method (MEM) suitable for multi-wavelength VLBI polarisation observations is presented and the advantage in resolution it possesses over the CLEAN algorithm is discussed and demonstrated using Monte Carlo simulations. This new polarisation MEM code has been applied to multi-wavelength imaging of the Active Galactic Nuclei 0716+714, Mrk 501 and 1633+382, in each case providing improved polarisation imaging compared to the case of deconvolution using the standard CLEAN algorithm. The first MEM-based fractional polarisation and Faraday-rotation VLBI images are presented, using these sources as examples. Recent detections of gradients in Faraday rotation measure are presented, including an observation of a reversal in the direction of a gradient further along a jet. Simulated observations confirming the observability of such a phenomenon are conducted, and possible explanations for a reversal in the direction of the Faraday rotation measure gradient are discussed. These results were originally published in Mahmud et al. (2013). Finally, a new error model for the CLEAN algorithm is developed which takes into account correlation between neighbouring pixels. Comparison of error maps calculated using this new model and Monte Carlo maps show striking similarities when the sources considered are well resolved, indicating that the method is correctly reproducing at least some component of the overall uncertainty in the images. The calculation of many useful quantities using this model is demonstrated and the advantages it poses over traditional single pixel calculations is illustrated. The limitations of the model as revealed by Monte Carlo simulations are also discussed; unfortunately, the error model does not work well when applied to compact regions of emission.

Problems with drawing lines: Theo-geographies of the Catholic parish in Ireland

While people in Catholic parishes in Ireland appear keenly aware of parish boundaries, these understandings are more often oral than cartographic. There is no digital map of all of the Catholic parishes in Ireland. However, the institutional Catholic Church insists that no square kilometre can exist outside of a parish boundary. In this paper, I explain a process whereby the Catholic parishes of Ireland were produced digitally. I will outline some of the technical challenges of digitizing such boundaries. In making these maps, it is not only a question of drawing lines but mapping people’s understanding of their locality. Through an example of one part of the digitisation project, I want to talk about how verifying maps with local people often complicates something which may have at first sight seemed simple. The paper ends on a comparison with how other communities of interest are territorialised in Ireland and elsewhere to draw out some broader theoretical and theological issues of concern.

Algorithms for indoor localization based on IEEE 802.15.4-2011 UWB and inertial sensors

In this thesis, extensive experiments are firstly conducted to characterize the performance of using the emerging IEEE 802.15.4-2011 ultra wideband (UWB) for indoor localization, and the results demonstrate the accuracy and precision of using time of arrival measurements for ranging applications. A multipath propagation controlling technique is synthesized which considers the relationship between transmit power, transmission range and signal-to-noise ratio. The methodology includes a novel bilateral transmitter output power control algorithm which is demonstrated to be able to stabilize the multipath channel, and enable sub 5cm instant ranging accuracy in line of sight conditions. A fully-coupled architecture is proposed for the localization system using a combination of IEEE 802.15.4-2011 UWB and inertial sensors. This architecture not only implements the position estimation of the object by fusing the UWB and inertial measurements, but enables the nodes in the localization network to mutually share positional and other useful information via the UWB channel. The hybrid system has been demonstrated to be capable of simultaneous local-positioning and remote-tracking of the mobile object. Three fusion algorithms for relative position estimation are proposed, including internal navigation system (INS), INS with UWB ranging correction, and orientation plus ranging. Experimental results show that the INS with UWB correction algorithm achieves an average position accuracy of 0.1883m, and gets 83% and 62% improvements on the accuracy of the INS (1.0994m) and the existing extended Kalman filter tracking algorithm (0.5m), respectively.

Developing the Cost of Large Carnivore Conflict Rapid Response Units - A Namibian Case Study

Namibia is home to half the world’s remaining wild cheetahs and - provides critical habitat for lions, leopards, spotted and brown hyena and African Wild Dogs. Despite such ecological importance, only 5% of cheetah's, <1% of African Wild Dogs', and similar percentages of remaining habitat for other large carnivores exists on officially protected lands. As a result, human/carnivore conflict is a large problem on private lands, where 60% of surveyed farmers will shoot any large carnivore on sight. This project explores building a carnivore rapid response team equipped to mitigate human/carnivore conflict through researching the financial costs of such an endeavor, with an eye on capitalizing potential benefits to all 6 Namibian large carnivore species.

Temporal structure and enablement representation for mutual wills: A Petri net approach

Those temporal formalisms that are sporadically found nowadays in the literature of AI & Law are based on temporal logic. We claim a revived role for another major class of temporal representation: Petri nets. This formalism, popular in computing from the 1970s, had its potential recognized on occasion in the literature of legal computing as well, but apparently the discipline has lost sight of it, and its practitioners on average need be tutored into this kind of representation. Asynchronous, concurrent processes—for which the approach is well‐suited—are found in the legal domain, in disparate contexts. We develop an example for Mutual Wills.

Adaptive decision-making in buildingEXODUS

Given the importance of occupant behaviour on evacuation efficiency, a new behavioural feature has been implemented into buildingEXODUS. This feature concerns the response of occupants to exit selection and re-direction. This behaviour is not simply pre-determined by the user as part of the initialisation process, but involves the occupant taking decisions based on their previous experiences and the information available to them. This information concerns the occupants prior knowledge of the enclosure and line-of-sight information concerning queues at neighbouring exits. This new feature is demonstrated and reviewed through several examples.

Adaptive decision-making in response to crowd formations in building EXODUS

Given the importance of occupant behavior on evacuation efficiency, a new behavioral feature has been developed and implemented into buildingEXODUS. This feature concerns the response of occupants to exit selection and re-direction. This behavior is not simply pre-determined by the user as part of the initialization process, but involves the occupant taking decisions based on their previous experiences and the information available to them. This information concerns the occupants prior knowledge of the enclosure and line-of-sight information concerning queues at neighboring exits. This new feature is demonstrated and reviewed through several examples.

Adaptive decision-making in buildingEXODUS in response to exit congestion

Given the importance of occupant behavior on evacuation efficiency, a new behavioral feature has been implemented into building EXODUS. This feature concerns the response of occupants to exit selection and re-direction, given that the occupant is queuing at an external exit. This behavior is not simply pre-determined by the user as part of the initialization process, but involves the occupant taking decisions based on their previous experiences with the enclosure and the information available to them. This information concerns the occupant's prior knowledge of the enclosure and line-of-sight information concerning queues at neighboring exits. This new feature is demonstrated and reviewed through several examples.

Self-adaptability and man-in-the-loop: a dilemma in autonomic computing systems

This paper addresses some controversial issues relating to two main questions. Firstly, we discuss 'man-in-the loop' issues in SAACS. Some people advocate this must always be so that man's decisions can override autonomic components. In this case, the system has two subsystems - man and machine. Can we, however, have a fully autonomic machine - with no man in sight; even for short periods of time? What kinds of systems require man to always be in the loop? What is the optimum balance in self-to-human control? How do we determine the optimum? How far can we go in describing self-behaviour? How does a SAACS system handle unexpected behaviour? Secondly, what are the challenges/obstacles in testing SAACS in the context of self/human dilemma? Are there any lesson to be learned from other programmes e.g. Star-wars, aviation and space explorations? What role human factors and behavioural models play whilst in interacting with SAACS?.