724 research outputs found
Non-linear optimization for parameter estimation for flood forecasting
Floods are the response of a catchment area to
severe rainfall events. Each catchment will have
its unique response which is dependent on its own
characteristics and the temporal and spatial
distribution of the oncoming rainfall event. A non
linear optimization technique has been applied to
historical data for rainfall and river flows of the
Kakanui catchment in North Otago, New Zealand,
to estimate the parameters of a model based on
the transfer function concept. The non linear
optimization is based on Powell algorithm.
Powell algorithm has been widely used in the
literature, and it is more efficient and faster than
the Simplex method (Press et al., 1989)
Observed rainfall events at two locations in the
Kakanui catchment, along with the corresponding
observed flows of the river have been utilized to
estimate the transfer function which represents the
response of the Kakanui catchment to rainfall
events. An adjusted form of Philip’s equation for
infiltration was used to estimate the abstraction of
the rainfall event and obtain the effective rainfall
which will contribute to the river flow. Weighing
factors were assigned to each of the rainfall sites
to obtain the best fit between observed and
forecasted flows. Nine flood events were used for
the calibration process, while two events were
utilized for the validation of the derived model.
The model has 19 parameters for the transfer
function, 2 parameters for the hydrologic
abstractions model, and 2 parameters for the
weighing factors of the rainfall sites. This results
in a total of 23 parameters for the developed
model. The ratio of observed cumulative rainfall
at Clifton Falls to the corresponding rainfall at the
Dasher for historical events is not consistent, and
varies significantly from one event to another.
This indicates the high variability of the spatial
distribution of rainfall events over the Kakanui
catchment. As these rainfall events were used in
the model calibration, it was difficult to obtain the
correct transfer function without proper
accounting for the spatial distribution of rainfall over the whole watershed. However, the model,
in general, performed satisfactory, given the
difficulty in representing the spatial variability of
the rainfall events. The model was capable of
simulating the flood hydrographs of several
events which were incorporated in its calibration,
but did not perform well with others. The model
was able to simulate well the flows of a flood
event which was not included in its calibration.
Moreover, in applying the derived model for a
real case event which occurred most recently on
30 July 2007, the model was able to forecast very
closely the peak flow, but the whole flow
hydrograph was not forecasted as good
Analyzing Disproportionate Reaction via Comparative Multilingual Targeted Sentiment in Twitter
Global events such as terrorist attacks are commented upon in social media, such as Twitter, in different languages and from different parts of the world. Most prior studies have focused on monolingual sentiment analysis, and therefore excluded an extensive proportion of the Twitter userbase. In this paper, we perform a multilingual comparative sentiment analysis study on the terrorist attack in Paris, during November 2015. In particular, we look at targeted sentiment, investigating opinions on specific entities, not simply the general sentiment of each tweet. Given the potentially inflammatory and polarizing effect that these types of tweets may have on attitudes, we examine the sentiments expressed about different targets and explore whether disproportionate reaction was expressed about such targets across different languages. Specifically, we assess whether the sentiment for French speaking Twitter users during the Paris attack differs from English-speaking ones. We identify disproportionately negative attitudes in the English dataset over the French one towards some entities and, via a crowdsourcing experiment, illustrate that this also extends to forming an annotator bias
Immobilization of halophilic Aspergillus awamori EM66 exochitinase on grafted k-carrageenan-alginate beads
A novel extreme halophilic exochitinase enzyme was produced by honey isolate Aspergillus awamori EM66. The enzyme was immobilized successfully on k-carrageenan-alginate gel carrier (CA) with 93 % immobilization yield. The immobilization process significantly improved the enzyme specific activity 2.6-fold compared to the free form. The significant factors influencing the immobilization process such as enzyme protein concentration and loading time were studied. Distinguishable characteristics of optimum pH and temperature, stability at different temperatures and NaCl tolerance for free and immobilized enzyme were studied. The immobilization process improved optimum temperature from 35 to 45 °C. The immobilized enzyme retained 76.70 % of its activity after 2 h at 75 °C compared to complete loss of activity for the free enzyme. The reusability test proved the durability of the CA gel beads for 28 cycles without losing its activity
Ecological Agro-ecosystem Sustainable Development in Relationship to Other Sectors in the Economic System, and Human Ecological Footprint and Imprint☆
Abstract Sustainable agriculture is the major economic sector (i.e. about 30% of Global economy) with the industrial and trading system in the world's economy. It is important to understand why the sustainable development is very important to the point of view of improving of human life and reducing the poverty. Additionally, we need to sustain our natural resources to be replenished and continue support our human population growth that is continued to increase in alarming rate rather than development, which is in a slow rate that does not meet the demands. This paper is to discuss the importance of global agro-ecosystems, to support humans' needs for feeding and continue their lives in a healthy and sustainable life and to function within the society. In addition, the paper will show the availability of the agriculture natural resources in terms of global ecological biological capacities in hectares and the trends in using these resources in terms of an ecological footprint in hectares. Additionally, we study the term of ecological human imprint in relation to the agro-ecosystem as suggested by Shakir Hanna et al., 2014 . Further the paper will address the impacts of agro-ecosystem on global economy and, further discuss the impacts of human technological advances on agro-ecosystems ecologically, economically, and social importance. Our results show that the global population will be 10.50 billion people in 2050 (i.e. 1.1% the current population growth). The available global cropped land is 2.36 billion global hectares in 2008.The question is the Earth able to provide food and other agricultural products to support the healthy living of all human beings in year 2050 at the current growth rate? The paper is discussing these concerns
EveTAR: Building a Large-Scale Multi-Task Test Collection over Arabic Tweets
This article introduces a new language-independent approach for creating a
large-scale high-quality test collection of tweets that supports multiple
information retrieval (IR) tasks without running a shared-task campaign. The
adopted approach (demonstrated over Arabic tweets) designs the collection
around significant (i.e., popular) events, which enables the development of
topics that represent frequent information needs of Twitter users for which
rich content exists. That inherently facilitates the support of multiple tasks
that generally revolve around events, namely event detection, ad-hoc search,
timeline generation, and real-time summarization. The key highlights of the
approach include diversifying the judgment pool via interactive search and
multiple manually-crafted queries per topic, collecting high-quality
annotations via crowd-workers for relevancy and in-house annotators for
novelty, filtering out low-agreement topics and inaccessible tweets, and
providing multiple subsets of the collection for better availability. Applying
our methodology on Arabic tweets resulted in EveTAR , the first
freely-available tweet test collection for multiple IR tasks. EveTAR includes a
crawl of 355M Arabic tweets and covers 50 significant events for which about
62K tweets were judged with substantial average inter-annotator agreement
(Kappa value of 0.71). We demonstrate the usability of EveTAR by evaluating
existing algorithms in the respective tasks. Results indicate that the new
collection can support reliable ranking of IR systems that is comparable to
similar TREC collections, while providing strong baseline results for future
studies over Arabic tweets
The optimal succinylcholine dose for intubating emergency patients: retrospective comparative study
Background : Succinylcholine remains the drug of choice for satisfactory rapid-sequence tracheal intubation. It is not clear from the literature why the 1 mg/kg dose of succinylcholine has been traditionally used. The effective dose (ED95) of succinylcholine is less than 0.3 mg/kg. The dose of 1 mg/kg represents 3.5 to 4 times the ED95. Objectives : To compare the effect of the traditionally used 1 mg/kg of succinylcholine with lower doses of 0.6 mg/kg and 0.45 mg/kg on intubation condition regarding the onset time, duration of action, duration of abdominal fasciculation, and the intubation grading. Methods : This retrospective comparative study was carried into three groups of ASA III & IV (American Society of Anesthesiologist's Physical Status III and IV) non-prepared emergency patients who were intubated at emergency department of Hamad General Hospital, Doha, Qatar during January 1st 2007 to August 31, 2010. The Institutional Research Board (IRB) approval was obtained. This study was limited to 88 patients who received fentanyl 1 µg/kg followed by etomidate 0.3 mg/kg intravenously as induction agents and succinylcholine as a muscle relaxant agent in doses of 0.45 mg/kg, 0.6 mg/kg, or 1 mg/kg. Results : Increasing the succinylcholine dosage shortened the onset time, prolonged the duration of action, and prolonged the duration of abdominal fasciculation significantly (P<.001). Tracheal intubation was 100% successful in the three groups of patients. Conclusion : Succinylcholine dose of 0.45 mg/kg provides an optimal intubation condition in ASA III & IV emergency non-prepared patients. Duration of action of succinylcholine is dose dependent; reducing the dose allows a more rapid return of spontaneous respiration and airway reflexes
Effects of L-carnitine and cryodevices on the vitrification and developmental competence of invitro fertilized buffalo oocytes
In the current, study the effect of the addition of L-carnitine (LC) in in vitro maturation (IVM) medium for buffalo oocytes and different cryo-devices on developmental competence. They were matured in IVM medium supplemented with 0.0, 0.3, 0.6 and 1.2 mg/mL of LC and vitrified by using either straw (ST), open pulled-straw (OPS), solid surface vitrification (SSV). The effects of LC during invitro fertilization and invitro culture on the developmental potential were examined. ST showed a higher recovery rate when using 0.6 mg/ml; viability rate (VR) when using 0.3mg/ml and lower zona pellucida (ZP) and cytoplasmic abnormalities when using 1.2 mg/ml LC (P<0.05). OPS showed a higher recovery and viability rates when using 0.3 mg (P<0.05). SSD showed a higher recovery and VR when using 0.6 mg/ml LC (P<0.05). Maturation and fertilization rates were increased when using 0.3 mg LC and OPS (P<0.05). Cleavage was increased in 0.3 (OPS) and 0.6 mg LC (SSD). The blastocyst rate was increased in 0.3 (OPS) and 0.6 mg/ml (SSD) (P< 0.05). In conclusion, 0.3 mg/ml LC and OPS gives a higher recovery and viability rates but 0.6 mg/ml LC and of both SSD and ST gives a higher recovery and viability rates
Dielectric Properties of the Quasi-Two-Dimensional Electron Liquid in Heterojunctions
A quasi-two-dimensional (Q2D) electron liquid (EL) is formed at the interface
of a semiconductor heterojunction. For an accurate characterization of the Q2D
EL, many-body effects need to be taken into account beyond the random phase
approximation. In this theoretical work, the self-consistent static local-field
correction known as STLS is applied for the analysis of the Q2D EL. The
penetration of the charge distribution to the barrier-acting material is taken
into consideration through a variational approach. The Coulomb from factor that
describes the effective 2D interaction is rigorously treated. The longitudinal
dielectric function and the plasmon dispersion of the Q2D EL are presented for
a wide range of electron and ionized acceptor densities choosing GaAs/AlGaAs as
the physical system. Analytical expressions fitted to our results are also
supplied to enable a widespread use of these results.Comment: 39 pages (in LaTeX), including 8 PostScript figure
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