scholarly journals A new scheduling method based on sequential time windows developed to distribute first-aid medicine for emergency logistics following an earthquake

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247566
Author(s):  
Jiaqi Fang ◽  
Hanping Hou ◽  
Changxiang Lu ◽  
Haiyun Pang ◽  
Qingshan Deng ◽  
...  

After an earthquake, affected areas have insufficient medicinal supplies, thereby necessitating substantial distribution of first-aid medicine from other supply centers. To make a proper distribution schedule, we considered the timing of supply and demand. In the present study, a “sequential time window” is used to describe the time to generate of supply and demand and the time of supply delivery. Then, considering the sequential time window, we proposed two multiobjective scheduling models with the consideration of demand uncertainty; two multiobjective stochastic programming models were also proposed to solve the scheduling models. Moreover, this paper describes a simulation that was performed based on a first-aid medicine distribution problem during a Wenchuan earthquake response. The simulation results show that the methodologies proposed in this paper provide effective schedules for the distribution of first-aid medicine. The developed distribution schedule enables some supplies in the former time windows to be used in latter time windows. This schedule increases the utility of limited stocks and avoids the risk that all the supplies are used in the short-term, leaving no supplies for long-term use.

2015 ◽  
Vol 4 (3) ◽  
pp. 54-58
Author(s):  
Гендон ◽  
A. Gendon

In article the main attractive fundamental characteristics determining the steady growth of world demand for mineral fertilizers in the long term are considered. However it is defined that such factors define need for fertilizers, but not solvent demand, and in the short term in all segments of branch excess of the offer over demand that can lead to reduction of prices of fertilizers, and also to decline in yield of mining and chemical business will be observed.


Ekonomika ◽  
2011 ◽  
Vol 90 (3) ◽  
pp. 39-57
Author(s):  
Dainius Butautas

Systematic analysis of the development of understanding the causes of inflation, taking supply and demand conditions as the central axis, offers a deeper insight into the inflation process and its essence. It is obvious that the long-term inflation impacting human, productive and financial resources can in no way be justified by extremely short-term benefits to a country’s budget or to monopolistic structures. Analysis of the literature clarifies and confirms the fact that in order for inflation to occur and significantly accelerate, the growth of demand factors must exceed that of supply factors during several years. The research shows that the policy of encouraging the demand, and thus a significant and long-lived inflation, is possible only in non-competitive oligopolistic economies marked by corruption and provoking emigration. On the other hand, adjustment of demand instruments to changes in supply is rather a result of fair competition. Interest rate change as an independent factor is shown to be important for the inflation process, especially for deflation, and therefore for the economy. Moreover, it is not completely clear whether delayed is the cause of inflation or its result, but it is obvious that the negative impact of delayed demand, as delayed human and social well-being, results in weaker supply and thereby also in higher poverty and inflation, all of them encouraging a more thorough examination of this problem. Analysis of the phenomenon of inflation over a historic period provides a realistic picture of this problem and shows the ways how to solve it.


2019 ◽  
Author(s):  
Stefano Picascia ◽  
Antonello Romano ◽  
Michela Teobaldi

An in-depth look into the mechanics of short term rentals in Italy. The study is based on a vast dataset comprising of all the properties listed on the Airbnb website in 10 major cities in the years 2015, 2016 and 2017. We discuss the spatial patterns of Airbnb supply and demand within and between cities, we then hypothesize on the possible drivers of the Airbnb offer and suggest a possible way to assess whether Airbnb supply could be driven by an economic advantage of short-term over long term letting. We also discuss the way the benefits of this particular incarnation of the sharing economy are shared among participants. Finally, we conclude by presenting a possible alternative way of regulating Airbnb.


Author(s):  
Wang-Pao Lee ◽  
Meng-Hsuan Chiang ◽  
Li-Yun Chang ◽  
Wei-Huan Shyu ◽  
Tai-Hsiang Chiu ◽  
...  

Memory consolidation is a time-dependent process through which an unstable learned experience is transformed into a stable long-term memory; however, the circuit and molecular mechanisms underlying this process are poorly understood. The Drosophila mushroom body (MB) is a huge brain neuropil that plays a crucial role in olfactory memory. The MB neurons can be generally classified into three subsets: γ, αβ, and α′β′. Here, we report that water-reward long-term memory (wLTM) consolidation requires activity from α′β′-related mushroom body output neurons (MBONs) in a specific time window. wLTM consolidation requires neurotransmission in MBON-γ3β′1 during the 0–2 h period after training, and neurotransmission in MBON-α′2 is required during the 2–4 h period after training. Moreover, neurotransmission in MBON-α′1α′3 is required during the 0–4 h period after training. Intriguingly, blocking neurotransmission during consolidation or inhibiting serotonin biosynthesis in serotoninergic dorsal paired medial (DPM) neurons also disrupted the wLTM, suggesting that wLTM consolidation requires serotonin signals from DPM neurons. The GFP Reconstitution Across Synaptic Partners (GRASP) data showed the connectivity between DPM neurons and MBON-γ3β′1, MBON-α′2, and MBON-α′1α′3, and RNAi-mediated silencing of serotonin receptors in MBON-γ3β′1, MBON-α′2, or MBON-α′1α′3 disrupted wLTM. Taken together, our results suggest that serotonin released from DPM neurons modulates neuronal activity in MBON-γ3β′1, MBON-α′2, and MBON-α′1α′3 at specific time windows, which is critical for the consolidation of wLTM in Drosophila.


BMJ Open ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. e036517
Author(s):  
Weiyi Ni ◽  
Wolfgang Kunz ◽  
Mayank Goyal ◽  
Yu Li Ng ◽  
Kelvin Tan ◽  
...  

ObjectivesEndovascular therapy (EVT) significantly improves clinical outcomes in patients with acute ischaemic stroke (AIS), while the time of EVT initiation after stroke onset influences both patient clinical outcomes and healthcare costs. This study determined the impact of EVT treatment delay on cost effectiveness of EVT in the Singapore healthcare setting.DesignA short-term decision tree and long-term Markov health state transition model was constructed. For each time window of symptom onset to EVT, the probability of receiving EVT or non-EVT treatment was varied, thereby varying clinical outcomes (modified Rankin Scale scores), short-term costs and long-term modelled (lifetime) costs; all of which were used in calculating an incremental cost-effectiveness ratio of EVT vs non-EVT treatment. Clinical outcomes and cost data were derived from clinical trials, literature, expert opinion, electronic medical records and community-based surveys from Singapore. Deterministic one-way and probabilistic sensitivity analyses were performed to assess the uncertainty of the model. The willingness to pay for per quality-adjusted life-year (QALY) was set to Singapore $50 000 (US$36 500).SettingSingapore healthcare perspective.ParticipantsThe model included patients with AIS in Singapore.InterventionsEVT performed within 6 hours of stroke onset.Outcome measuresThe model estimated incremental cost-effectiveness ratios (ICERs) and net monetary benefits (NMB) for EVT versus non-EVT treatment, varied by time from symptom onset to time of treatment.ResultsEVT performed between 61 min and 120 min after the stroke onset was most cost-effective time window to perform EVT in the Singapore population, with an ICER of Singapore $7197 per QALY (US$5254) for performing EVT at 61–120 min versus 121–180 min. The resulting incremental NMB associated with receipt of EVT at the earlier time point is Singapore $39 827 (US$29 074) per patient at the willingness-to-pay threshold of Singapore $50 000. Each hour delay in EVT resulted in an average loss of 0.54 QALYs and 195.35 healthy days, with an average net monetary loss of Singapore $26 255 (US$19 166).ConclusionsFrom the Singapore healthcare perspective, although EVT is more expensive than alternative treatments in the short term, the lifetime ICER is below the willingness-to-pay threshold. Thus, healthcare policies and procedures should aim to improve efficiency of pre-hospital and in-hospital workflow processes to reduce the onset-to-puncture duration.


1960 ◽  
Vol 34 (1) ◽  
pp. 1-23 ◽  
Author(s):  
Edith T. Penrose

Growth is governed by a creative and dynamic interaction between a firm's productive resources and its market opportunities. Available resources limit expansion; unused resources (including technological and entrepreneurial) stimulate and largely determine the direction of expansion. While product demand may exert a predominant short-term influence, over the long term any distinction between “supply” and “demand” determinants of growth becomes arbitrary.


2017 ◽  
Vol 32 (1) ◽  
pp. 25 ◽  
Author(s):  
Johanna Carolina Vega Sequeda ◽  
Sven Zea ◽  
Gladys Bernal

El incremento en la frecuencia e intensidad de eventos oceánicos extremos limita la capacidad de recuperación de los ecosistemas, amenazando su subsistencia. Con el fin de entender la relación entre la estructura y salud arrecifal y los eventos extremos ambientales, se analizaron series de datos ambientales de las islas del Rosario (e.g., temperatura del mar, caudal y/o salinidad, turbidez), en comparación con cobertura coralina y signos de deterioro (e.g., blanqueamiento, enfermedades). En las series de tiempo de las variables ambientales se calcularon los eventos oceánicos que excedieron un umbral estadístico, estableciendo su intensidad, duración y frecuencia. Para los atributos de la comunidad, se evaluaron dos estaciones del Sistema Nacional de Monitoreo de Arrecifes Coralinos en Colombia (SIMAC), en dos ventanas temporales (largo plazo, 1998–2013 y corto plazo, 2013 - 2014). Los eventos extremos de temperatura superficial del mar, el caudal de descarga continental y la turbidez asociada fueron las principales variables relacionadas con la reducción de la cobertura coralina. El blanqueamiento masivo de 2005 y otros eventos posteriores dieron como resultado una reducción de la cobertura coralina entre 2004 y 2010. En el corto plazo no se registraron fuertes eventos extremos ni cambios en las formaciones coralinas, si bien el estrés térmico y las reducciones de salinidad en la época de lluvias estuvieron asociados con un ligero blanqueamiento en noviembre de 2014. Aunque los signos de deterioro sean bajos, es importante considerarlos, ya que la sinergia entre perturbaciones continuas puede conllevar a una pérdida de cobertura del coral.  Effect of extreme oceanic events in the coral formations of Islas del Rosario,  Colombian CaribbeanThe increase in frequency and intensity of extreme oceanic events limits the capacity of recovery of ecosystems, threatening their subsistence. Thus, in order to understand the relationship between coral health and extreme environmental events, data on sea temperature, runoff and / or salinity, turbidity were analyzed in the Islas del Rosario in comparison with coral cover, and coral signs of deterioration (e.g., bleaching, coral diseases). In the time series of environmental variables, oceanic events that exceeded a statistical threshold were calculated, establishing their intensity, duration and frequency. The attributes of the community were studied through observations in two stations of the National Coral Reef Monitoring System in Colombia (SIMAC), assessed in two time windows (long term, 1998-2013 and short term, 2013-2014). The extreme events of sea surface temperature, river discharge and associated turbidity, were the main variables related to the reduction of coral cover. The massive coral bleaching of 2005 and other subsequent events resulted in a reduction in coral coverage between 2004 and 2010. During the short-term observations there were no strong extreme events or changes in coral formations, although thermal stress and reductions in salinity in the rainy season were associated with a slight bleaching in November 2014. Although the signs of deterioration are low, it is important to consider them, since the synergy between continuous disturbances can lead to a loss of coral cover.


2012 ◽  
Vol 1 (1) ◽  
pp. 27-40
Author(s):  
Fabrizio Rossi

The objective of this paper is to investigate whether mergers create value for shareholders in both the short and long term. For this purpose, 120 announcements of mergers that were registered in Italy during the period 1994-2006 among listed companies were examined. The short-term analysis was conducted using the event study methodology in order to estimate the cumulative abnormal returns (CARs) in the time window around the announcement date (-10, +10). In this work, the sample of 120 mergers was divided into two sub-samples: the first considers the mergers that were carried out in all sectors of the economy, and the second focuses only on bank mergers. From the results obtained it would appear that, while the sub-sample of all mergers registered a statistically significant value creation for the shareholders of both the bidder and target companies, values also confirmed by combined analysis, the second sub-sample registered negative values for bidder companies and positive values for target companies. Negative values also seem to be confirmed by the results of the combined analysis both at the date of announcement and throughout the entire period of observation. For the long-term analysis the Buy and Hold Abnormal Returns methodology (BHARs) was used, with which it was possible to observe the returns for three years. In the 36 months following the merger, the portfolio showed a significant destruction of value.


2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Bowei Xu ◽  
Yuqing Wang ◽  
Junjun Li

Uncertainties exist and affect the actual port production. For example, at the beginning of 2020, the sudden outbreak of COVID-19 seriously affected terminal production and increased the short-term pressure of handling at container terminals. Consequently, a large number of containers were stacked at terminals, and the problem of terminal congestion became more serious. To solve the congestion problem of container terminals and ensure the priority dispatch of emergency materials, this study uses the optimized arrival patterns of external trucks and a priority dispatch strategy for emergency materials to establish a bilevel optimization model for container terminals and proposes a chaotic genetic algorithm based on logistic mapping as a solution. Through numerical experiments, the algorithm proposed in this study was compared with the genetic algorithm and adaptive genetic algorithm. The experimental results show that the model and algorithm proposed in this study can effectively reduce the total cost of containers in a terminal while ensuring the priority dispatch of emergency materials, reducing the overlapping part of the time window, optimizing the arrival mode of external trucks, and reducing the waiting time of external trucks, effectively alleviating the terminal congestion problem.


2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.


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