Replenishment Levels Research Articles

A data-driven optimization model for the scattered storage assignment with replenishment

Modern warehouses are transitioning from pure storage facilities to order fulfillment centers. To improve order-picking efficiency, picking areas are restricted to small zones to save picker travel distance and thus can only store a limited quantity of SKUs. As a result, replenishment must be frequently carried out which not only causes intensive working efforts but also impacts the order-picking efficiency. Despite of the important role of replenishment, it has been seldom considered in storage assignment planning. This paper proposes a novel optimization model for the storage assignment problem considering both the order-picking and replenishment operations. Instead of the traditional first-extract-then-optimize paradigm, we develop an effective solution method for the problem by integrating the extraction and optimization steps together to avoid the loss of information. Intensive experiments and a case study are presented, the results of which indicate significant advantages of our model against the state-of-the-art counterpart. Several managerial implications are derived: (1) Order data implies substantial useful information for storage assignment planning, including but not limited to the demand correlation of products; (2) The replenishment efforts are intensive and negatively correlated to the order-picking efforts, which therefore should not be neglected in storage assignment planning; (3) To minimize the total working efforts, the optimal replenishment level r of the (r,S) replenishment policy should be more than 0.4S but less than 0.6S with respect to each SKU.

Impact of an enterprise controlled substance management system on labor and inventory costs.

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. To evaluate the impact of an enterprise controlled substance (ECS) management system with integration of analytics software on labor requirements and inventory cost within a health-system pharmacy. A prospective, pre-post observational study was designed to assess the impact of implementing a solution that connects disparate systems with the integration of analytics software. Three study modules were implemented over approximately 18 months. The intervention consisted of implementation of new CS vaults, a centralized server, an automated central medication inventory system, and inventory optimization analytics software. The number of transactions and time spent on CS reports were compared before and after implementation to determine labor and inventory efficiencies. Both of the study facilities had a decrease in CS daily stockouts and an increase in inventory turns compared to baseline, while the total number of transactions (vends) at the central vault and decentralized dispensing cabinets increased. The addition of analytics allowed for establishment of informed changes to periodic automated replenishment levels. Additionally, both facilities saw a reduction in the number of expired medications, and there was subsequently a reduction in the total reverse distributor costs. Finally, both facilities had a reduction in the amount of time spent on manual tasks associated with reconciling and managing discrepancies. An inventory management system integrated with an advanced analytics tool provided a reduction in the time spent on receiving, storing, and reconciling CS records while the number of transactions increased. The ECS solution enhanced the visibility of the chain of custody while closing the loop between reporting and receiving inventory, eliminating or reducing the frequency of manual processes.

Impact of connected dispensing technology with advanced analytics in a multicenter health system.

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. This study was designed to evaluate the impact of enterprise inventory optimization (EIO) technology and analytics on pharmacy labor, costs, and medication availability within a large integrated delivery network (IDN). This article describes a mixed-methods, postmarket observational study assessing the impact of a solution of disparate technologies including automated dispensing cabinets (ADCs), centralized pharmacy inventory software, and controlled substance vaults connected by an inventory optimization analytics (IOA) tool. Four study modules were implemented over a 10-month period. The intervention consisted of implementation of the IOA software, linking the disparate automated technologies. Transactional data was collected and aggregated with user perception survey data in both the pre- and postintervention periods. Descriptive and comparative statistical testing was used to assess outcomes. A total of 11 facilities with bed counts ranging between 22 and 908 beds were included in this study. At an enterprise level, users were able to complete an average of 2.8 times more periodic automated replenishment (PAR) level changes post intervention, resulting in an estimated enterprise labor avoidance of over 1 full-time equivalent (2,099 labor hours) annually. Despite an enterprise decision to increase ADC inventory on hand from a 3-day supply to a 5-day supply, 5 sites (45%) had a decrease in total inventory, while 9 sites (82%) saw a decrease in ADC inventory costs. Additionally, 7 sites (64%) saw a reduction in the ADC stockout percentage and all 11 sites (100%) saw a decrease in the central pharmacy stockout percentage post intervention. Integration and optimization of connected inventory management technology was observed to have positive impacts on improving labor productivity, reducing ADC inventory carrying costs, and increasing medication availability.

IoT and machine learning approach for the determination of optimal freshwater replenishment rate in aquaponics system

IoT and machine learning approach for the determination of optimal freshwater replenishment rate in aquaponics system

Land drainage functioning and hydrological impacts in rural catchments: model development and field experiments

The development of an integrated theory of subsurface drainage based on hydrology and hydrogeology concepts is presented. The historical context, the main hypothesis derived from the Boussinesq equation and the validation of the model predictions are discussed. Theoretical developments of this equation demonstrate that a single parameter (σ)—a combination of soil and drainage system properties—is sufficient for predicting the dynamics of subsurface drain flow rates. We also demonstrate that these drain flow rates are a function of the level of water replenishment in the system (classically the water table elevation), of the recharge intensity of the aquifer and of a buffer function related to the swelling or deflation of the water table shape during recharge events. For values of σ>1, the buffer role of the water table is negligible. In that case approx. 13% of the water table recharge contributes to the flow rate, which is shown to explain the observed disconnection between water table elevations and peak flow rates at the outlet of classic agricultural drainage systems and to predict these peak flow rates accurately. A modelling approach based on this theory and validated experimentally (SIDRA model) allowed us to test the quality of the peak flow prediction. The SIDRA model also includes a surface runoff module and has been coupled to different modelling tools and used to analyse the impacts of subsurface drainage on water quality. The approach contributed towards the development of tools that helped to connect better the drainage systems to the hydrological functioning of watersheds.

Determination of the Most Efficient Forage Sorghum Irrigation Scheduling Strategies in the U.S. Central High Plains Using the AquaCrop Model and Field Experiments

The current status of water resources in the U.S. Central High Plains necessitates adopting water conservation practices to move toward a sustainable agricultural economy. Identifying proper irrigation scheduling techniques is a conservative practice to maintain the sustainability of the agricultural systems. However, conducting field experiments is time and money consuming. Thus, the utilization of crop models, such as AquaCrop, could be a convenient alternative to field experiments. The FAO AquaCrop model was calibrated and validated for simulating forage sorghum yield response to various deficit irrigation conditions in a semi-arid region. Afterwards, the model was used to investigate the efficiency of the pre-season and in-season irrigation scheduling scenarios. In this study, the soil water status at the planting time was considered as the indicator of the pre-season irrigation level. Therefore, the pre-season irrigation scenarios were arranged as the replenishment of soil water deficiency at the time of planting at up to 30, 50, and 100% of the soil’s total available water for the first 60 cm of soil depth and the same replenishment levels for the entire crop root zone (150 cm soil depth). Then, AquaCrop long-term (37 years) simulations of forage sorghum biomass and irrigation water use efficiency reactions to three levels of maximum allowable depletion (MAD) (40, 55, and 70%) were compared to three fixed irrigation interval (4, 6, and 10 days) scenarios by considering six pre-season irrigation conditions (36 scenarios). The scenarios analysis found the 10-day irrigation interval and the MAD levels of 55% and 70% to be the most efficient irrigation scheduling strategies if combined with pre-season irrigation that brought the crop root zone (0–150 cm soil depth) to field capacity. Moreover, the 40% MAD application was the least efficient strategy. This study’s outputs can be a baseline for establishing forage sorghum irrigation scheduling in the U.S. Central High Plains. However, exploring the interactions of irrigation scheduling strategies with other irrigation and agronomic practices, such as salinity management and fertilizer application, is highly recommended.

Water production function and optimal irrigation programme for drip irrigated castor (Ricinus communis L.)

Water shortage for crop production necessitates adequate knowledge of the crop water production function to make decisions on water allocation for optimum returns from castor crop under surface drip irrigation. The study was conducted in rabi 2009-10 at Agricultural college farm, Rajendranagar, Hyderabad. The different drip irrigation schedules at 40, 60 and 80 per cent pan evaporation replenishment levels either kept constant throughout the crop life or combinations at vegetative, flowering and development stages were compared with surface check basin at (0.8 IW/CPE ratio) irrigation. The results showed that drip irrigation at 0.6 Epan replenishment up to flowering and 0.8 Epan later on registered comparable seed yields with drip irrigation scheduled at either at 0.6 or 0.8 Epan and was significantly superior over other treatments and the best fit water production function was quadratic (R2= 0.99). The optimum quantity of water (ETc) for maximum net returns under prevailing prices (water and castor @ `10 and 30 ha/mm and kg/ha, respectively) was 381.4 ha mm with a resultant seed yield of 3611 kg/ha. The gross returns, net returns and net return/rupee invested varied from ` 72194 to 144447/ha, ` 36808 to 108018/ha and 1.040 to 3.049, respectively.

Deepwater dissolved oxygen shows little ecological memory between lake phenological seasons

ABSTRACT Depletion of deepwater dissolved oxygen (DO) in lakes has become increasingly prevalent and severe because of many external stressors, potentially threatening human-derived ecosystem services ranging from drinking water quality to fisheries. Using year-round, high-frequency DO data from 12 dimictic lakes, we compared 3 measures of deepwater DO depletion during winter and summer: DO depletion rate, DO minimum, and hypoxia duration. Hypoxia (DO < 3 mg L−1) occurred in over half of the lakes and persisted an average of 83% longer in summer than in winter. While we found no difference in DO depletion rates between winter versus summer, these rates were significantly related to lake morphology in winter but trophic state in summer. In assessing cross-seasonal linkages, we found limited evidence for significant legacy effects in deepwater DO availability. Only fall mixing efficacy significantly responded to the previous summer’s minimum DO saturation, but it always reached moderate to high DO replenishment levels (>65%) regardless of the previous summer’s DO depletion severity. This lack of ecological memory in deepwater DO depletion across seasons suggests that deepwater DO largely resets during spring and fall mixing periods in most years in these dimictic lakes. Understanding the patterns and drivers in deepwater DO depletion in both winter and summer is a key step forward for predicting future chemical and biological consequences of seasonal DO depletion and managing lake ecosystem health, as well as the effects that climate change may have on these patterns.

Supply-hub-based Collaborative Replenishment Decisions for Enterprise Supply Logistics Under Demand Uncertainty

To address the collaborative replenishment problem of enterprise supply logistics, a Supply-hub-based collaborative replenishment decision model is constructed from the perspective of horizontal collaboration among suppliers and the introduction of component demurrage costs and product out-of-stock penalty costs. The number of suppliers participating in the system, the replenishment level of suppliers and the impact of demand uncertainty on the operational cost of supply logistics are analysed. The results show that: the participation of multiple suppliers can reduce the increase of supply logistics operating costs to a certain extent; as the service level increases, the supply logistics operating costs increase and then decrease; the impact of demand uncertainty on the supply logistics operating costs can be mitigated to a certain extent by the coordination function of Supply-hub.

Production of edible flowers: irrigation and biotechnology

Garden pansy is a versatile gardening plant – it produces beautiful colorful edible-flowers with high value in gourmet cuisine. The use of irrigation and biotechnology in garden pansy cultivation can provide gains in flower productivity and nutritional value. The goal of this study was to evaluate the growth and edible flower production in garden pansy plants, submitted to different levels of irrigation and mycorrhizal inoculation. The experiment was conducted in randomized blocks in the 2 x 5 factorial design, with the presence and absence of mycorrhizal inoculation in combination with 5 levels of irrigation with 6 replicates, in a greenhouse. There was no significant interaction between the factors mycorrhizal inoculation and irrigation levels by the F test. Under the tested conditions, the mycorrhizal inoculation was unable to provide significant changes in the growth, development and flowering of garden pansy plants. It was concluded that no symbiotic efficiency was pointed out between the mycorrhizal fungus used and garden pansy plants. The best growth and yield results for cultivating and producing edible flowers of garden pansy were obtained at the 100% replenishment level of water evaporation.

Soil organic carbon transfer in aggregates subjected to afforestation in karst region as indicated by 13C natural abundance

The measurement of 13C natural abundance provides valuable information in studying carbon (C) incorporation in soil aggregates. Exploring the pathways of C between aggregates of different size classes are vital to further understand the stabilization of soil organic matter (SOM) and aggregate formation. However, little is known on the mechanism of C stabilization in soil, especially when subjected to afforestation effects in karst rocky desertification area. Soil in the 0–20 cm layer was collected from two afforestation types [natural secondary forest (NF) and artificial Zanthoxylum bungeanum forest (AF)] in the karst rocky desertification area, with cropland (CL) as the reference. Stable isotope fractionation was used to analyze the dynamic changes in organic carbon (OC) in aggregates, and the Δ13C (difference in δ13C between the bulk soil and aggregate fractions) was utilized to quantify the C flow in aggregates under different land use types and soil layers. Results showed that afforestation significantly affected the dynamics of soil aggregate OC. Afforestation on cropland increased the number of large macroaggregates (>2 mm, LMA) and decreased the proportions of small macroaggregates (0.25–2 mm, SMA), microaggregates (0.053–0.25 mm, MI), and silt + clay fraction (<0.053 mm, SC). With the increase in aggregate class size, the OC content in aggregates rose under CL and AF, but no obvious regularity was found in NF. The proportion of new SOC was higher in NF (27.0%) than in AF (20.6%) and in 0–10 cm soil layer (27.3%) than in 10–20 cm soil layer (20.3%) under different afforestation measures. No significant differences in particle size were found among aggregates (P > 0.05). The δ13C in bulk soil and aggregates was significantly decreased by afforestation and increased with the increment in soil depth. Stable isotope analysis results showed that the flow of OC was mainly from larger aggregates to smaller aggregates in CL and AF, which is consistent with the stabilization mechanism of SOM in aggregate hierarchy theory. However, the C flow occurred from smaller aggregates to larger aggregates in NF topsoil due to that newly input OC is first associated with MI and then incorporated into macroaggregates during soil aggregation process. The different human disturbance frequencies and the replenishment levels of plant biomass through litter input, root biomass, and exudates resulted in variation in aggregate turnover (formation and breakdown) among CL, AF and NF. These conclusions can provide sufficient reference for the formation and stabilization of aggregate-associated OC.

A study on the physiological parameters of corn during the jointing stage of growth under soil water stress based on the PSII light quantum yield (QY)

Water stress is a major factor limiting corn production in the semi-arid and semi-humid regions of the world. Well-scheduled irrigation is necessary to increase seed yield and ensure yield stability in these regions. A reasonable and intelligent irrigation system is generally based on the measurement of soil water content or the monitoring of corn water demand. Therefore, it is vital to be able to quickly and accurately determine the optimal threshold of the physiological parameters of corn.In this paper, in order to find the optimal threshold of the physiological parameters of corn, experiments in the open fields were conducted from February to June by measuring the corn growth under different degrees of water stress using remote sensing instruments. In this experiment, sweet corn 18# was chosen as the experimental subject, and several parameters of remote sensing spectral index such as leaf water potentia, Normalized difference vegetation index (NDVI), photochemical vegetation index (PRI), and PSII light quantum yield (QY) were measured at the same time every day-along with the varying moisture status—for the duration of the experiment. For this experiment, it was very important to set the varying moisture statuses as the moisture controlling standard. Leaf water potential and QY were selected as indexes to check the different moisture statuses. The QY proved to be sensitive to the water stress of corn and was chosen as the indicator. Furthermore, the effects on the corn under differing levels of water stress were explored by analyzing the variation trend of different remote sensing spectral indices. The main results and conclusions are as follows:(1) Differing degrees of water stress at the jointing stage of corn growth will cause the inhibition (in varying degrees) of leaf water potential, QY, NDVI, and PRI; and will also inhibit the processes of transpiration and photosynthesis. (2) After halting the water stress, with the different levels of water replenishment, the leaf water potential, QY, NDVI, and PRI will display the characteristics of the compensation phenomena. The compensation levels will depend on the degree of water stress. When the water stress is mild, all of the leaf water potential indexes, QY, NDVI, PRI will recover to normal levels or even succeed normal levels in a very short period of time-known as the super compensation effect. Meanwhile, for moderate levels of water stress, the compensation phenomena is also present; however, the replenishment of water cannot reach normal levels. Further, the water replenishment effect does not appear under conditions of severe water stress. This indicates that it is beneficial in maize growth for the corn to be under conditions of mild water stress.(3) Lastly, from the significance of the QY, water potential, PRI, and NDVI to water stress, it is apparent that the QY is the most reliable. Therefore, QY is the most reasonable choice to guide the water-saving irrigation in irrigated farming areas.

Size and age structure and population of the kaluga Huso dauricus and the Amur sturgeon Acipenser schrenckii (Acipenseridae) in the Amur river

Based on research findings from 1963–2021 the analysis of size-age indicators, qualitative structure of populations and changes in the number of kaluga Huso dauricus and Amur sturgeon Acipenser schrenckii in the river was carried out. Amur. It is established that in the period from the 60s. last century to 2008–2011 in the kaluga and the Amur sturgeon in the Amur River, there was a reduction in the size range and number of age groups, the proportion of mature individuals, the level of replenishment of populations with juveniles and abundance. The main reason for these changes is INN fishing (illegal, unreported and unregulated). According to the results of research in 2021, it was revealed that the modern number of kaluga exceeded the figures of the 60s. last century. In the Amur sturgeon, the process of population growth has not yet reached the historical values noted in the 1960s–1970s, but exceeded the indicators of the 1980s and subsequent years. Despite the noted positive points, at present, the population of kaluga in the river. Amur is characterized by the smallest average size and age over 60 years of study. The situation is better for the Amur sturgeon, which is due to the lower interest of fishermen in this species and the large volume of release of its juveniles from sturgeon hatcheries (ORZ). The reason for the positive dynamics is the artificial reproduction that has been developing on the Amur over the past decade, as well as the introduced set of restrictions on the Pacific salmon fishery. To further increase the number of Kaluga and Amur sturgeon in the river. Amur, it is proposed to maintain the current volumes of artificial reproduction of sturgeons and extend the restrictive measures in the salmon fishery for at least the next 10 years.

Optimizing Medication Distribution in Automated Dispensing Cabinets: Dashboard Implementation and Evaluation

Purpose: To determine the impact of a business intelligence dashboard tool to optimize automated dispensing cabinets (ADCs). Methods: A pre-post implementation design was used to evaluate key performance indicators (KPI) before and after the implementation of a dashboard tool to optimize ADCs. Eleven ADCs were optimized in 2 phases according to dashboard recommendations: (1) removal of unused medications over 90 days, (2) adjusting periodic automatic replenishment (PAR) levels, and (3) addition of commonly dispensed medications. The KPI measures that were assessed included inventory cost, no. of stocked medications, stockout percentage, vend to refill ratio, and missing dose messages from nursing. An interrupted-time-series regression was used to quantify the impact of ADCs on the means of measured KPIs. Results: Differences in mean distribution of all KPIs, except missing dose, between the pre- and post-ADC periods during the Phase 1 period were statistically significant: inventory cost (54.2 vs 56), stockout percentage (1.55 vs 1.12), vend to refill ratio (6.83 vs 6.14), and missing dose messages (221 vs 229). Only the mean ADC utilization (57.3 vs 64) and missing dose (228 vs 179) were statistically different between the pre- and post-ADC periods in Phase 2. The interrupted-time-series analysis showed that Phase 1 optimization significantly reduced the cost of inventory (β = −$1.238.00, P < .01), no. Stocked medications (β = −8.2, P < .01), percent stockout (β = −.49%, P < .01), vend-to-refill ratio (β = −1.29%, P<.01) and ADC utilization (β = −.2, P < .01). Conclusion: Automated dispensing cabinets optimization, through the use of a dashboard tool, had a positive impact on almost all measured KPIs.

Water regimes on soil covered with plastic film mulch and relationships with soil water availability, yield, and water use efficiency of papaya trees

Plastic film mulches have the potential to be used in papaya production, mainly aiming to reduce water application in semi-arid regions. However, there is a lack of technical information and the need to introduce mulching practices in papaya orchards. The objective of this work was to evaluate the effects of plastic film mulch and irrigation depths on soil water availability (SWA), stomatal conductance, leaf temperature, and agronomic traits of papaya trees. The study was carried out during 2018 and 2019 in Jaíba city, located northern Minas Gerais state, in the Brazilian semi-arid region. The experiment was a split plot design, with soil cover conditions assigned to the plots (bare soil and mulched soil) and water replenishment levels to subplots (25%, 50%, 75%, 100% and 125% of crop evapotranspiration [ETc]). Plants were drip irrigated with water replenishments based on climate data. Soil moisture was measured along time and agronomic and physiological characteristics of papaya trees, as well. Water tensions were higher in treatments with lower water replenishments. Results showed that the increase in irrigation depth favors leaf-area growth rate, stomatal conductance, yield, and water footprint of papaya. The use of mulch together with the increase in water replenishment levels contributes for maintenance of the soil water content between the upper limit of SWA and 75%SWA. The use black plastic mulching with drip irrigation in medium-textured soil saves up to 152 L of water per Kg of fruit, and increase productivity up to 34% by replenishing the crop evapotranspiration every irrigation event. The use of black plastic as ground cover is technically feasible for keeping soil water availability above 75% by irrigation supply of at least 75% of ETc on sand-clay-loam soil.

DEVELOPMENT FEATURES OF THE UKRAINIAN STOCK MARKET AS A COMPONENT OF STATE FINANCIAL SECURITY

Introduction. Peculiarities of functioning and structure of the stock market of Ukraine play an important role in ensuring the state economic security and, in particular, financial. The purpose of the article is to analyze the state and features of the modern stock market of Ukraine, to investigate its impact on the state of financial security of the country. Results. Imbalances in the primary securities market are due to the small number and volume of issues, as well as the predominance of issuers of state banking institutions and state corporations, which carried out the issue to keep banks at the required level of capital and replenishment. The volume and number of bond issues are significantly lower compared to stocks. There are currently four exchanges in Ukraine, but primary stock market operations are focused on the PFTS. The secondary securities market of Ukraine is more developed in Ukraine (the total amount of transactions is more than 90% of the volume of exchange contracts during the entire analyzed period). Transactions are carried out mainly on stock exchanges – PFTS and “Perspective”. The trend of the results of the secondary stock market has improved (significantly decreases the value of indicators – linear deviation, variance, oscillation coef­ficient), however, the value of the oscillation coefficient still indicates a lack of homogeneous and balanced environment. Approximations to the state of homogeneity can be characterized by stock exchange contracts concluded on government bonds. At the same time, the volume of concluding exchange contracts is generally insignificant, and the share of exchange contracts on government bonds in total is approaching almost 100%; therefore, it can be concluded that the entire stock market is characterized by significant heterogeneity and imbalance. Conclusions. The stock market of Ukraine does not fulfill its key function – investment. The stock market of Ukraine is characterized by pronounced imbalances. At the same time, it should be emphasized that the structure of the stock market is characterized by dynamic processes, so the creation of a fully balanced environment can not be a priority. The stock market of Ukraine mostly serves the needs of the public sector of the economy and in no way contributes to the de­velopment of not only the real but also the financial sector of the economy. That is, the security of the stock market is directly related to the security of debt and budget, which are components of the financial security of the state.

Macroscopic plasma analysis from 1D-radial kinetic results of a Hall thruster discharge

A radial particle-in-cell model of the weakly-collisional plasma discharge in a Hall thruster, provides the non-Maxwellian velocity distribution functions (VDF) of ions and electrons. The model considers a radial magnetic field, secondary electron emission from the two walls, and phenomenological models of anomalous electron scattering. The electron VDF is used to assess the different terms in the macroscopic momentum and energy equations, identifying those differing from the standard fluid model for a near-Maxwellian VDF. The pressure tensor consists of an anisotropic gyrotropic part and a small gyroviscous part. Nonetheless, the gradient of this last one affects the cross-field electron current density, generating radial undulations that resemble those reported for near-wall conductivity. A gyroviscous energy flux is identified too. The heat flux parallel to the magnetic lines does not follow a conductive-type law but a convective-type one, already found in other weakly-collisional plasmas. The tails of the electron velocity distribution function are partially depleted due to wall collection, leading to reduced electron fluxes of particles and energy, which are characterized with parameters useful for fluid models. Differences in the plasma response for annular and planar channel geometries are highlighted. The levels of replenishment of the electron VDF and of the asymmetries in radial profiles differ for isotropic and anisotropic anomalous scattering models.

Reproductive hyperallometry and managing the world’s fisheries

Marine fisheries are an essential component of global food security, but many are close to their limits and some are overfished. The models that guide the management of these fisheries almost always assume reproduction is proportional to mass (isometry), when fecundity generally increases disproportionately to mass (hyperallometry). Judged against several management reference points, we show that assuming isometry overestimates the replenishment potential of exploited fish stocks by 22% (range: 2% to 78%) for 32 of the world's largest fisheries, risking systematic overharvesting. We calculate that target catches based on assumptions of isometry are more than double those based on assumptions of hyperallometry for most species, such that common reference points are set twice as high as they should be to maintain the target level of replenishment. We also show that hyperallometric reproduction provides opportunities for increasing the efficacy of tools that are underused in standard fisheries management, such as protected areas or harvest slot limits. Adopting management strategies that conserve large, hyperfecund fish may, in some instances, result in higher yields relative to traditional approaches. We recommend that future assessment of reference points and quotas include reproductive hyperallometry unless there is clear evidence that it does not occur in that species.

A triple [formula omitted]-thresholds base-stock policy subject to uncertainty environment, returns and order cancellations

This paper studies a continuous-review (S,s,ℓ) inventory model that extends the familiar (S,s)-policy by including returns and order cancellations. The demand and return processes follow independent compound Poisson processes. We assume a random shelf life, a random lead time and early losses. Our objective is to find a replenishment level S, a reorder level s, and a threshold cancellation level ℓ that minimizes the total expected cost per time unit under lost sales. The cost structure includes variable and fixed costs for an order, a holding cost, a penalty cost, a handling cost for returns, a relocation cost, and costs for end of life and early loss. Via Markovian framework, we derive the steady-state probabilities for the inventory level, and construct closed-form expressions for the average cost functions. Using a numerical study, we investigate how the best S,s and ℓ, are impacted by the system’s parameters, such as returns, demands (rate, mean and variability), and order cancellations. We illustrate the impact of the return flow on the best policy and the cost, and show that ignoring returns may yield a substantial loss. Consequently, we compare our model to a relatively simple one with no returns but with less demand, and specify when the latter model can be used as a good approximation. Finally, we identify situations where an earlier-cancellation policy is more cost effective. Our framework is completed by providing two efficient search algorithms for numerically finding the optimal parameters. We show that both algorithms significantly reduce the computational effort compared to the basic algorithm.

Sugarcane response to different soil water replenishment‐based deficit irrigation treatments during different growth stages in an Indian semi‐arid region*

AbstractThe objective of this study was to investigate the effect of a specified water deficit during a specified growth stage by replenishing root zone soil water. A field experiment was conducted with 27 treatments in randomized block design comprising groupings of different root zone soil water replenishment levels (100%, 70%, and 40%) during different growth stages (tillering, grand growth, and maturity) over three full‐year seasons of 2015–2017 in clay soils of semi‐arid western India. The full‐season 100% soil water replenishment produced higher yield (174 t ha−1), net monetary returns, and benefit‐cost (B:C) ratio that decreased linearly with linear decrease in water use. Full‐season 40% soil water replenishment caused a reduction in yield of about 40.7%, whereas a 70% replenishment caused a reduction in yield by 14%. The quality parameters of sugarcane improved non‐significantly in high‐water‐deficit conditions compared with full irrigation. The smaller range of water productivity in all seasons indicated a linear decrease when irrigation water increased and yields decreased under the different treatments. The net income and B:C ratio related to marketable cane yield was highest in 100% soil water replenishment (INR 274,000 ha−1 and 1.58, respectively) and then declined with the decrease in water use depth. The water deficit imposed during the long‐duration grand growth stage had adverse effects on cane yield, followed by tillering and maturity stages. Deficit irrigation scheduling at 100%, 70%, and 40% soil water replenishment at tillering, grand growth, and maturity stages, respectively, was appropriate. The water requirement of seasonal sugarcane under full irrigation and water deficit conditions was 1,320 and 1,150 mm, respectively.