Peninsular Malaysia hosts a remarkable biodiversity and has succeeded in maintaining sustainable populations of endangered species. Historical sources show that this achievement was made possible ...thanks to a conservation apparatus set up during the British colonial period, which continued and developed further after Independence. Under the pressure of colonists interested in wildlife conservation, such as big game hunter Theodore Hubback, the Malay States under British rule drafted protection laws, established parks and reserves -- including the King George V National Park -- and set up a Game Department charged with pest control, law enforcement, parks management and wildlife conservation. The British Game Wardens were backed by concerned Malaysians who were able to take over after Independence despite the lack of means allocated to wildlife protection. The Malayan Nature Society, founded in 1940 by the federal Chief Game Warden, assisted the Game Department in its task. While the Society remained a British club up to the early 1970s, some of its few Malaysian members became very influential in independent Malaysia. After Independence, the Society was at the centre of a network that connected conservationists, scientists, Game Wardens and decision makers. It was this network of institutions and individuals that allowed Malaysia not only to pursue the conservation agenda set by the British, but also to draw its own conservation policy.
Fish pond systems are managed with different practices. Among them, a dry period with one year without water is applied in some cases to promote mineralization of the sediments and control the ...development of pathogenic bacteria. This dry period induces a drastic disturbance on the plant communities. The objective of this work was to study the influence of a one-year dry period applied every five to seven years on aquatic plant diversity and abundance. For this, we studied the aquatic plant community of 149 fish ponds during the first year after a dried period (Y1), and ponds with a dried period dating back two years (Y2), three years (Y3), four years (Y4) and five to seven years (Ysup5). According to Jackknife index, mean species richness was highest for Y1, with 29 species compared to the other years (24 species for Y2; 19 for Y3; 15 for Y4 and 17 for Ysup5). A total of 15 species were identified as species unique to Y1 and were competitive, fast colonizer and disturbance-tolerant species. Most of these Y1 species developed during the dry year and remain only one year after refilling. After Y1, the evolution of communities was linked to the phenomenon of nestedness based on a loss of several species but not on a complete turnover, with most of species present independently of time. We conclude that a periodic dry period maintains a cycle in plant succession and accommodates highest species richness at the beginning of the cycle.
Based on Cambodian and French archival records, which include colonial and local administration reports, tax rosters and judicial sources, this paper explores landownership in Cambodia in the 1930s. ...It shows that, contrary to common belief, land access was already an issue in the 1930s. The study of tax registers of three communes in the province of Kompong Thom presents a Khmer rural society dominated by peasants with average-sized landholdings, but where landless peasants or those with very small holdings also existed. It also stresses that women were able to become efficient farm operators. In addition, this analysis of the different sources available shows that Khmer rural society in Kompong Thom was a form of gerontocracy dominated by men aged over 40.
•Using a dataset of 100 fish ponds, we determined tipping points for aquatic plant richness and cover in fish ponds along a gradient of chlorophyll α, water transparency, Total N or Total P and over ...different years.•We evaluated the relationship between tipping points, nutrient loads and weather conditions.•The major tipping points ranged between 5 and 15μg/L chlorophyll α concentrations.•Tipping points can vary from year to year due to the influence of weather conditions on the competition between phytoplankton and aquatic plants.
High levels of nutrients in fish ponds by fish farming may cause significant eutrophication leading to a loss in species richness and a decrease of cover of aquatic plants to phytoplankton dominance. This shift can be represented by a tipping point where a significant change in the state of the ecosystem is observed such as a change from high to low aquatic plants species richness and cover. A total of 100 fish ponds were studied during five years in the Dombes region, France, to determine tipping points in aquatic plant richness and cover using chlorophyll α (CHL), water transparency, Total N (TN) and Total P (TP) gradients with two statistical methods. The relationships between tipping points, nutrient loads and yearly variations in weather conditions were also evaluated. Looking at the five years data, tipping points were observed in aquatic plant richness at 6 and 60μg/L for CHL, and at 3.90mg/L for TN concentration; as well as at 70cm for water transparency, but no tipping point was found with TP. For aquatic plant cover, tipping points were observed at 11μg/L for CHL, 2.42mg/L for TN, 0.05mg/L for TP, and at 62cm for water transparency. These tipping points showed a significant decrease of aquatic plant species richness and cover, linked to the nutrient concentrations which drive the competition between the primary producers phytoplankton and aquatic plants. However, tipping points could vary significantly between years. The inter-annual variability may be due to an early occurrence of phytoplankton blooms in some ponds in a year preventing the establishment of aquatic plants, and thus influencing the value of tipping points. Weather conditions influence the competition between primary producers by impacting chlorophyll α and nutrients concentrations. When weather conditions supported increased nutrient concentrations, the development of phytoplankton and aquatic plants was facilitated and tipping points in aquatic plant richness and cover occurred with relatively high values. Thus, a significant decrease of plant cover and richness occurred at higher level of nutrients compared to the other years. In these cases, aquatic plants dominated over phytoplankton for the spring period, and also often during summer. In conclusion, tipping points observed are mainly linked to the competition between aquatic plants and phytoplankton. In shallow and eutrophic systems like fish ponds where nutrients are not a limiting resource, weather conditions act temporarily during spring as the main regulator of this competition.
This paper presents organic based logic and memory circuits. All those circuits are made with organic N- and P-type transistors. Organic complementary NAND and NOR gates were characterized and show ...performance equivalent to or better than the literature-reported ones. The presented memory circuits include an SRAM memory point and an edge-triggered flip-flop. The flip-flop is made of six organic two-input and three-input NAND gates, representing a total of 26 organic transistors for a surface of 170 mm 2 . The maximum operating frequency of this flip-flop is 220 Hz under a supply of ±20 V. All the circuits were manufactured using a standard organic sheet-to-sheet process in ambient air. Electrical characteristics remain identical after repeated measurements. Finally, a model matching the presented circuits' behavior was carried out, permitting the design of more complex circuits.
In aquaculture, management practices such as supplementary feeding or fertilisation of water are generally considered to improve fish yield in ponds or shallow lakes. Nevertheless, in semi-natural ...systems where many ponds or lakes are situated in a cultural landscape, this is much less evident for certain fish farmers because fish production systems are often quite extensive, and fish production is only one economic activity among others for these fish farmers. In this paper we analyse the influence of different management practices on fish yield and nutrient status of fish ponds’ water and sediments, and we have an additional regard on potential implications of this in the perspective of the European Water Framework Directive. This directive demands that artificial water bodies such as fish ponds have to attain a good ecological potential in 2015, and thus to adapt water body management to achieve this.
In total, 83 fish ponds were studied from 2007 to 2009 in the Dombes region, France. This region is characterised by 1100 nutrient rich fish ponds located in a heterogeneous agricultural landscape with cropping, animal husbandry and forestry. Different water parameters (PO43−, NO3−, total P, total N, NH4+, chlorophyll-a) were analysed from April to October in each year. Sediments were sampled in March and October and analysed for available P, total N, organic matter and Ca concentration. Data about pond management practices such as fertilisation of pond water, supplementary feeding as well as fertilisation and liming of pond grounds when they are emptied and let dried out during a year, and harvested fish were collected by interviewing pond owners and pond managers.
The main results found are that the combination of the annual management practices supplementary feeding and fertilisation, increased significantly the fish yields. When combining the annual with the non-annual management practices fertilisation of pond grounds and liming of pond grounds during a year when ponds are emptied, highest yield were obtained. Using only the non-annual practices, yields could be positively influenced. Lowest yields were found when no management practice was applied. Significant, but contrasting effects of pond management practices on water or sediment parameters were only found for available P of sediments and NO3− for the management practices supplementary feeding, fertilisation of water, or liming of the pond ground. Whereas available P of sediments showed higher values with the three practices, NO3− in the water showed lower values. Although only few significant differences were found, means of parameters showed a certain trend as they were in many cases, besides for total N and NO3−, higher with the management practice.
Our results show that there is a limited effect of pond management practices on the chemical status of the pond water and sediments. This also suggests a limited potential to change management practices to respond to the demand of the European Water Framework Directive for good water quality and ecological potential.
Les sources historiques montrent que la remarquable biodiversité de la péninsule malaise et les espèces menacées qu’elle abrite ont été préservées en partie grâce aux actions de conservation prises ...pendant la période coloniale, poursuivies et développées après l’indépendance. Sous l’impulsion de quelques coloniaux, tel l’amateur de grande chasse Theodore Hubback, les États de la péninsule malaise sous domination britannique ont adopté des législations de protection de la faune sauvage, créé des parcs et réserves, notamment le parc national King George V, et mis en place un département de protection de la vie sauvage. Ce dernier était en charge du contrôle des animaux considérés comme nuisibles, de l’application des lois, de la gestion des parcs et de la conservation des espèces. Les game warden britanniques étaient aidés par des Malaisiens engagés qui ont pris la relève après l’indépendance, malgré un manque criant de moyens. La Malayan Nature Society, créée en 1940 par le chief game warden fédéral, a aidé le département dans sa tâche. Jusqu’au début des années 1970, cette association était avant tout un club d’expatriés, mais certains parmi ses rares membres malaisiens sont devenus très influents dans la Malaisie indépendante. Elle s’est ainsi trouvée au cœur de réseaux qui permettaient de mettre les militants de la conservation, les scientifiques, les experts internationaux et les agents du département de la vie sauvage en contact avec les décideurs politiques. La Malaisie a ainsi pu poursuivre les programmes conçus sous domination britannique et développer ses propres politiques de conservation.
Over the emerging industry 4.0 era, the building control system performance depends on the development of smart sensor technology. Nowadays, the building control engineers challenge on the design of ...high-capacity smart sensor susceptible to operate with high speed of data processing. In this context, this paper introduces a pioneer research work on the negative group delay (NGD) circuit original application for room temperature anticipation useful for smart-building control. The real-time anticipation of sensor data by using a low-pass (LP) NGD digital circuit is studied. This approach enables minimizing the latency time for optimizing control action. The unfamiliar LP-NGD digital circuit design method and theoretical formulation are described for anticipating thermal wave experimentation in real-time. The digital circuit equation coefficients are computed regarding the time-advance of anticipated thermal completely arbitrary waveform signal. The main interest of using the NGD method-based for thermal wave anticipation regarding temperature variation from heater and freezer control is demonstrated. The anticipation feasibility is illustrated from the minute scale time-advance LP-NGD digital circuit implemented on the STM32® microcontroller unit. The NGD characterization is performed from frequency domain analysis and cosine waveform pulse transient test. Then, the -30 seconds to -10 seconds real-time-advance of temperature variation is verified by calculation and experimentation. The present study result opens a promising NGD method application for the advanced fault control of a future industrial system by anticipating system failures.
This paper investigates on the theorization, design, fabrication and measurement of original phase shifter (PS) operating with two-step stair phase behavior. The innovative stair PS is designed with ...unfamiliar stop-band (SB) negative group delay (NGD) passive circuit. The elementary unfamiliar SB-NGD topology constituted by resistive, inductive, and capacitive lumped network is described. Acting as an RF and microwave circuit, the S-matrix model is expressed in function the RLC-network parameters. Thus, the canonical form of unfamiliar SB-NGD transfer function (TF) represented by the transmission coefficient is established. The unfamiliar SB-NGD circuit equations in terms of the NGD parameters are formulated. The established theory is validated comparing the calculated, simulated, and measured S-parameters and group delays (GDs). Results with a very good agreement showing unfamiliar SB-NGD behavior are observed around the central frequency 2.45 GHz and bandwidth of 100 MHz. An innovative application of unfamiliar SB-NGD function for the communication system front-end is developed. The developed application concept of unfamiliar SB-NGD circuit is illustrated by designing a microwave device operating as a PS presenting a two-step stair response completely original behavior. The basic theory, design and implementation of the two-step stair PS concept are introduced. To validate the two-step stair PS principle, a proof of concept (PoC) is designed based distributed element based inductive and capacitive microstrip elements. The simulated and measured results of the PS PoC are in good agreement. The experimental results confirm the feasibility of two-step stair PS with phase jumping from −70°±4° (from 2 GHz to 2.3 GHz) to −104°±2° (from 2.6 GHz to 3.0 GHz). The investigated unfamiliar SB-NGD function-based stair PS is promising for future development 5G and 6G communication system.
Recent investigation reports that certain electronic circuits operate with the unfamiliar negative group delay (NGD) function. It is fundamentally stated that the NGD circuits can be classified in ...different types. For example, we have the simplest ones as LP and HP NGD circuit types. So far, all the NGD studies are focused on simple type function. In step up of the research about the NGD electronic circuit engineering, this paper develops an original theory of electronic circuit topology operating with double NGD-type behavior. The study consists in the theorization of three-port circuit simultaneously generating LP and HP NGD function types. The proposed three-port innovative circuit under study is innovatively composed of resistive-capacitive (RC) network of Tee-shaped topology. Moreover, the LP and HP double-NGD circuit is a first order cell which does not contain any inductive component. The LP and HP NGD analyses of the Tee-topology is based on the 3-D S-matrix modelling. Analytical investigation based on classical circuit theory is elaborated to determine the S-matrix model from the equivalent admittance matrix. The identification of the double-NGD function is established from the LP- and HP-NGD canonical forms. Hence, the specific double-NGD characteristics are defined in function of the R and C elements constituting the three-port topology. To validate the developed double-NGD theory, a proof-of-concept (PoC) of SMD lumped component-based three-port circuit is designed, simulated, fabricated and tested. The calculated, simulated and measured results from the three-port circuit PoC prototype in very good agreement confirm the double-NGD behavior. The proposed innovative NGD three-port circuit design is useful in the future for the synchronization of signals propagating through multi-way communication system.
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