Middle Time Period Research Articles

Assessment of the sustainability of groundwater utilization and crop production under optimized irrigation strategies in the North China Plain under future climate change

Over-exploitation of groundwater due to intensive irrigation and anticipated climate change pose severe threats to the water and food security worldwide, particularly in the North China Plain (NCP). Limited irrigation has been recognized as an effective way to improve crop water productivity and slow the rapid decline of groundwater levels. Whether optimized limited irrigation strategies could achieve a balance between groundwater pumping and grain production in the NCP under future climate change deserves further study. In this study, an improved Soil and Water Assessment Tool (SWAT) model was used to simulate climate change impacts on shallow groundwater levels and crop production under limited irrigation strategies to suggest optimal irrigation management practices under future climate conditions in the NCP. The simulations of eleven limited irrigation strategies for winter wheat with targeted irrigations at different growth stages and with irrigated or rainfed summer maize were compared with future business-as-usual management. Climate change impacts showed that mean wheat (maize) yield under adequate irrigation was expected to increase by 13.2% (4.9%) during the middle time period (2041–2070) and by 11.2% (4.6%) during the late time period (2071–2100) under three SSPs compared to the historical period (1971–2000). Mean decline rate of shallow groundwater level slowed by approximately 1 m a−1 during the entire future period (2041–2100) under three SSPs with a greater reduction for SSP5–8.5. The average contribution rate of future climate toward the balance of shallow groundwater pumping and replenishment was 62.9%. Based on the simulated crop yields and decline rate of shallow groundwater level under the future climate, the most appropriate limited irrigation was achieved by applying irrigation during the jointing stage of wheat with rainfed maize, which could achieve the groundwater recovery and sustainable food production.

Unveiling the time course mechanism of bone fracture healing by transcriptional profiles.

Bone fracture healing is a time-consuming and high-priority orthopedic problem worldwide. Discovering the potential mechanism of bone healing at a time course and transcriptional level may better help manage bone fracture. In this study, we analyze a time-course bone fracture-healing transcriptional data set in a rat model (GSE592, GSE594, and GSE1371) of Gene Expression Omnibus (GEO). RNA was obtained from female Sprague-Dawley rats with femoral fracture at the initial time (day 3) as well as early (week 1), middle (week 2), and late (week 4) time periods, with nonfracture rats used as control. Gene Ontology (GO) functional analysis and pathway examinations were performed for further measurements of GSEA and hub genes. Results indicated that the four stages of bone fracture healing at the initial, early, middle, and late time periods represent the phases of hematoma formation, callus formation, callus molding, and mature lamellar bone formation, respectively. Extracellular organization was positively employed throughout the four stages. At the hematoma formation phase, the muscle contraction process was downregulated. Antibacterial peptide pathway was downregulated at all phases. The upregulation of Fn1 (initial, early, middle, and late time periods), Col3a1 (initial, early, and middle time periods), Col11a1 (initial and early time periods), Mmp9 (middle and late time periods), Mmp13 (early, middle, and late time periods) and the downregulation of RatNP-3b (initial, early, middle, and late time periods) were possible symbols for bone fracture healing and may use as therapeutic targets. These findings suggest some new potential pathways and genes in the process of bone fracture healing and further provide insights that can be used in targeted molecular therapy for bone fracture healing.

Gamma band VMPFC-PreCG.L connection variation after the onset of negative emotional stimuli can predict mania in depressive patients

ObjectiveBecause of the similar clinical symptoms, it is difficult to distinguish unipolar disorder (UD) from bipolar disorder (BD) in the depressive episode using the available clinical features, especially for those who meet the diagnostic criteria of UD, however, experience the manic episode during the follow-up (tBD). MethodsMagnetoencephalography recordings during a sad expression recognition task were obtained from 81 patients (27 BD, 24 tBD, 30 UD) and 26 healthy controls (HCs). Source analysis was applied to localize 64 regions of interest in the low gamma band (30–50 Hz). Regional functional connections (FCs) were constructed respectively within three time periods (early: 0–200 ms, middle: 200–400 ms, and post: 400–600 ms). The network-based statistic method was used to explore the abnormal connection patterns in tBD compared to UD and HC. BD was applied to explore whether such abnormality is still significant between every two groups of BD, tBD, UD, and HC. ResultsThe VMPFC-PreCG.L connection was found to be a significantly different connection between tBD and UD in the early time period and between tBD and BD in the middle time period. Furthermore, the middle/early time period ratio of FC value of VMPFC-PreCG.L connection was negatively correlated with the bipolarity index in tBD. ConclusionsThe VMPFC-PreCG.L connection in different time periods after the onset of sad facial stimuli may be a potential biomarker to distinguish the different states of BD. The FC ratio of VMPFC-PreCG.L connection may predict whether patients with depressive episodes subsequently develop mania.

Widening Survival Disparities between AYA with ALL Treated in Pediatric Vs. Adult Centers: A Population-Based Study Using the IMPACT Cohort

Background: Survival outcomes in adolescents and young adults (AYA) with cancer have not improved at the same rates as those in children. Studies in AYA with acute lymphoblastic leukemia (ALL) have shown that pediatric-based treatment protocols result in better survival compared to adult protocols. Consequently, many adult centers have begun to treat AYA ALL with pediatric protocols. Whether this change in practice has diminished survival disparities between pediatric and adult centers has not been established.Methods: The IMPACT Cohort comprises all Ontario, Canada AYA 15-21 years old diagnosed with one of six common cancers (including ALL) between 1992 and 2011. Detailed demographic, disease, treatment, and outcome data were collected through chart abstraction and validated by content experts. Locus of cancer care (pediatric vs. adult center) was determined based on where the majority of chemotherapy was delivered in the first three months after diagnosis. Linkage to population-based health administrative data identified cancer events (relapse, death) that were not detected through chart abstraction. Various predictors of locus of care were examined, including age (continuous variable), gender, time period (1992-1998 vs. 1999-2005 vs. 2006-2011), rural residence, and socioeconomic status using logistic regression. The impact of the above predictors and of locus of care on event-free (EFS) and overall survival (OS) was determined using Cox proportional hazard models. Events included disease progression, relapse, death, and second malignancies.Results: The cohort included 271 patients with ALL, 152 (56%) of whom received therapy at an adult center. In multivariable analysis, older patients [odds ratio (OR) 11.9 per year; 95th confidence interval (CI) 6.1-25.0] and those in the earliest time period (1992-1998 vs. 2006-2011, OR 3.5; 95CI 1.1-10.7) were more likely to be treated in an adult center. The 5-year EFS of patients treated at a pediatric center was 69.8%±4.2% vs. 50.7%±4.0% at adult centers (p=0.0006). 5-year OS was 78.0%±3.9% vs. 58.7%±5.5% (p=0.0006). For the entire cohort, there was no significant improvement in EFS over time. In multivariable analysis, only locus of care was significantly associated with EFS [adult vs. pediatric hazard ratio (HR) 4.0; 95CI 1.4-11.9]; age and time period were not predictive. The disparity in both EFS and OS between pediatric and adult cancer centers widened over time (Table 1). In the earliest time period (1992-1998) there was no significant different in OS between adult vs. pediatric centers (HR 1.8; 95CI 0.8-4.3). The HR increased and became statistically significant in the middle time period (1999-2005; HR 2.4; 95CI 0.9-5.6) and widened further in the most recent time period (2006-2011; HR 4.3; 95CI 1.4-13.8).Conclusions: Despite studies showing improved survival outcomes in AYA with ALL treated on pediatric-based protocols, and the increased use of such protocols at adult centers, outcomes in Ontario did not improve over the 20-year study period. Contrary to expectations, disparities in survival between pediatric and adult centers widened, with the largest disparities seen in the most recent time period. These results suggest that at a population-level, the use of pediatric protocols may not be sufficient to abolish locus of care-based outcome disparities. Future analyses will look at the impact of protocol adherence, delays in therapy, toxicity, and hospital volume on survival. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Assimilation of FY-3D MWHS-2 Radiances with WRF Hybrid-3DVAR System for the Forecast of Heavy Rainfall Evolution Associated with Typhoon Ampil

AbstractA detailed investigation about the effects of the Microwave Humidity Sounder-2 (MWHS-2) radiances on board the Fengyun-3D (FY-3D) satellite is combined with developments within the Weather Research and Forecasting Data Assimilation (WRFDA) system and analyses on the evolution of the heavy rainfall associated with Typhoon Ampil during 23–24 July 2018. In the analysis field, the position of Typhoon Ampil is found out to be distinctly affected by the MWHS-2 assimilation. The experiment that assimilates MWHS-2 radiances through hybrid-3DVAR generates the best analysis with large increments around the typhoon, which contributes to the typhoon moving inland to the southwest. In the forecast fields, the MWHS-2 assimilation improves the rainfall in not only the accumulated amount, but also the evolution characteristics. The hybrid-3DVAR experiment reduces the RMSE of the rainfall amount, and enhances the spatial correlation and the fractions skill score of the rainfall evolution to the greatest extent, followed by the 3DVAR MWHS-2 experiment. As for the cause of the rainfall improvements, analyses suggest that it could be closely connected with the characteristics of the circulation structures related to the typhoon evolution. On one hand, the increases of the rainfall amount and intensities in the MWHS-2 assimilation experiments (previously underestimated) correspond to the strengthened typhoon structures with strong anomalies in both the upper-layer temperature and the lower-layer geopotential height. On the other hand, the better rainfall evolution in the hybrid-3DVAR experiment could be explained by its clearer evolution of the structure of typhoon under the effects of an approaching upper trough, and its smallest typhoon track errors around the middle time period.

Day time variations of zooplankton species composition: observations from the wetlands of Assam, India

Abstract: Aim An attempt to justify the variations in the species composition of zooplankton over the day time period was made using the freshwater lakes of Assam, India, as a model study area. Methods The water bodies were sampled using a conical plankton net five times between 6 am and 6 pm in a day during July 2014. Apart from diversity analysis (SHE analysis), discriminant function analysis and a regression tree were built to justify the variations in the zooplankton species composition in the different time periods in a day. Results Repeated sampling during day time indicated the presence of 34 zooplankton species with varied composition over the different time periods. The species richness and abundance of Copepoda, Cladocera and Rotifer differed significantly revealed through the ANOVA (for rotifers – F4, 170 = 28.792; for cladocerans – F4, 170 = 16.343; for copepods - F4, 170 = 9.027). Apparently, the rotifer and copepod abundance was prominent during the early (6am) and late time (6pm) periods of a day while the cladoceran abundance was significant during the middle time periods (12 noon to 3pm) of a day. Variations in the relative abundance of the zooplankton species within a day were sufficient to discriminate the time periods significantly. The regression tree indicated the rotifer abundance (node 1), followed by the cladoceran and the copepod abundances (node 2). The nodes representing cladocerans explained 30.86% of the data while the copepod explained 69.14% data as a split from the rotifer groups. Conclusions A correspondence of high and low abundances of rotifers and cladocerans was characteristic of the species composition of the zooplankton in the study area. The variations in the species composition suggests that the zooplankton exhibits movements either in horizontal or vertical directions induced by physical and/or biological factors. Further studies may be adopted to elucidate the effects of the predators and environmental variables that shape the community of the zooplankton in shallow tropical lakes.

A semi-analytical model for pressure transient analysis of hydraulic reorientation fracture in an anisotropic reservoir

Fracture reorientation can be used to increase well production in an anisotropic reservoir. The principal focus of this work is on the transient pressure analysis for a hydraulic reorientation fracture in a rectangular anisotropic reservoir. By employing the nodal analysis technique, a set of diffusivity equations are developed to describe the flow in a hydraulic reorientation fracture. Then, a semi-analytical solution is obtained by coupling the point source solution and the discrete fracture solution. The validation of this work is demonstrated by comparing the previous study and the numerical simulation for a reorientation fracture. Five typical flow regimes can be observed on this model's transient response. Flux along the reorientation fracture is also generated to analyze the flux distribution at different time. Furthermore, type curves are obtained to investigate the effect of the key parameters on the transient flow behavior, including principal fracture angle, reoriented fracture angle, permeability anisotropy, fracture conductivity and fracture length ratio. For a rectangular anisotropic reservoir, the influence of principal fracture angle, permeability anisotropy and fracture conductivity on the type curves is concentrated in the early-time and middle-time periods, and reoriented fracture angle and fracture length ratio mainly affect the formation linear flow regime.

Theoretical analysis of lithium‐ion battery failure characteristics under different states of charge

SummaryLithium‐ion batteries (LIBs) are extensively applied in various portable electronic equipment because of their high energy density power. However, accidents related to LIBs frequently occur. This study focuses on failure results, characteristics, and phenomena. Lithium‐ion batteries under different states of charge (SOCs) (0%, 30%, 50%, 80%, 100%, and 120%) at high temperatures have been investigated with the thermal abuse test. During the experiments, several typical failure processes were captured. According to the phenomena, 2 failure modes (smoke and jet fire) and 3 stages (primary reaction, tempestuous reaction in the middle time period, and extinguishing reaction in the final stage) were observed. A substantial amount of gas was vented, and jet fire was detected in the middle period. Only gas vented when the SOC was lower than 50%, whereas vented gas and jet fire were detected simultaneously when the SOC exceeded 50%. The results indicated combustible behaviors and exothermic reactions related to the SOC. An increase in the SOC caused a decrease in the thermal runaway initial temperature and the maximum increase in temperature. A higher SOC determined intense chemical reactions in the cell at higher temperatures, which caused a significant amount of materials to spew out of the batteries as well as additional mass loss. Relationships between failure characteristics and internal reactions were analyzed. The SOC should be lower than 50% in transportation or storage. The intercalated lithium capacities were the main reason for the series of domino reactions, which caused runaway in the terminal. These studies can serve as a reference for safety applications, transportation, and loss prevention in LIBs.

Gastric cancer incidence in the Romagna Region of Italy: A spatial and temporal analysis

BackgroundThe worldwide decrease in gastric cancer incidence is due to a birth-cohort-dependent decrease in exposure to major risk factors. MethodsIn an area of northern Italy with a historically strong internal geographical gradient in gastric cancer incidence, variations in rates by municipality and age group between 1987 and 2008 were evaluated. The study period was divided into three nonadjacent periods. End points included: age- and sex-standardised incidence rates; incidence rate ratio between age- and sex-standardised incidence rates; smoothed relative risks of gastric cancer incidence, and posterior probabilities of the relative risk being >1. ResultsIn 1987–1990, the estimate of posterior probabilities of relative risk being >1 showed a higher incidence in hilly/mountainous areas. Between 1987–1990 and 2005–2008, a uniform decrease of more than 50% was observed (incidence rate ratio: plain, 0.45 (95% confidence interval 0.40–0.51); hill, 0.44 (0.34–0.58); mountain, 0.48 (0.22–1.02)). The decrease in the mountainous area was weak in the middle time period, with an incidence rate ratio of 0.92 (0.46–1.84), and intensified afterwards. The decrease occurred earlier and was more pronounced among younger people. In 2005–2008, gastric cancer risk was uniform across ages and municipalities. ConclusionsThe observed changes in gastric cancer incidence is the epilogue of a birth-cohort-dependent decrease in exposure to major risk factors.

Laparoscopic Splenectomy with Technical Standardization and Selection Criteria for Standard or Hand-Assisted Approach in 390 Patients with Liver Cirrhosis and Portal Hypertension

Laparoscopic splenectomy (LS) is still challenging in patients with liver cirrhosis and portal hypertension. This study was designed to establish safe and less invasive LS in patients with liver cirrhosis and portal hypertension. We analyzed 390 patients with liver cirrhosis and portal hypertension, who underwent LS between 1993 and 2013. Patients were divided into 3 time periods; early (1993 to 2004, n = 106); middle (2005 to 2008, n = 159); and late (2008 to 2013, n = 125). During the middle time period, standardized technique for LS and selection criteria for hand-assisted LS were adopted. Patients with spleen volume ≥ 1,000 mL by CT volumetry, large perisplenic collateral vessels, and/or Child-Pugh score ≥ 9, underwent hand-assisted LS. During the late time period, the selection criteria were refined and patients with spleen volume ≥ 600 mL underwent hand-assisted LS. Conversion to open splenectomy decreased (10.4% in the early time period, 1.9% in the middle time period, and 3.2% in the late time period, p = 0.004), median blood loss decreased (300g, 87g, and 98g, respectively, p < 0.001), and the success rate of pure LS tended to improve (87.2%, 89.5%, and 98.0%, respectively, p = 0.110). Mortality was 0% in each time period, Clavien-Dindo grade IIIb or more complications tended to decrease (5.7%, 2.5%, and 0.8%, respectively, p = 0.081), and technique-related complications decreased significantly (10.4%, 3.8%, and 2.4%, respectively, p = 0.014). Laparoscopic splenectomy is now a safe and less invasive approach, even in patients with liver cirrhosis and portal hypertension, because of its technical standardization with the refined selection criteria for pure or hand-assisted LS.

The Effect of ABCB1 C3435T Polymorphism on Cyclosporine Dose Requirements in Kidney Transplant Recipients: A Meta-Analysis.

Cyclosporine A (CsA) is a substrate of the multi-drug efflux pump P-glycoprotein (P-gp) encoded by ABCB1. Among the various single nucleotide polymorphisms (SNPs) of ABCB1, C3435T has been extensively investigated to determine the relationship with the pharmacokinetics of CsA. However, the results are controversial. This meta-analysis was designed to evaluate the influence of C3435T SNP on the dose-adjusted trough (C0 /D) and peak (Cmax /D) concentrations of CsA. Based on a literature search of four authoritative databases, 13 studies since 2001 concerning 1293 kidney transplant recipients were included. The results indicated a significant difference of C0 /D and Cmax /D between 3435CC and 3435TT genotype carriers (weighted mean difference (WMD) of C0 /D: 4.18 (ng ml(-1))/(mg kg(-1)), 95% CIs: 1.00-7.37, p = 0.01; WMD of Cmax /D: 20.85 (ng ml(-1))/(mg kg(-1)), 95% CIs: 2.25-39.46, p = 0.03). Subgroup analysis by ethnicity demonstrated that C0 /D was lower in Asian CC versus TT genotype carriers (WMD = 10.32 (ng ml(-1))/(mg kg(-1)), 95% CIs: 4.78-15.85, p = 0.0003) but did not vary by genotype for Caucasian recipients. Moreover, significant variation of C0 /D was found at 1 week and 1-3 months after transplantation between CC and TT genotype carriers. Therefore, this meta-analysis showed a correlation between ABCB1 C3435T polymorphism and the dose-adjusted concentration of CsA. Patients with 3435CC genotype will require a higher dose of CsA to achieve target therapeutic concentrations when compared with 3435TT carriers after kidney transplantation, especially in the Asian population and especially during the early and middle time periods after transplantation.

Time trends between 1987 and 2007 for perfluoroalkyl acids in plasma from Swedish women

Perfluoroalkyl acids (PFAAs) are a large group of chemicals which are highly persistent in both nature and humans. The use of the most prominent ones, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), was reduced in the early 21st century, and since then levels in human matrices have decreased. However, these two compounds have been exchanged by other PFAAs, for which time trends have not been as extensively investigated. By the use of 80 plasma samples collected between 1987 and 2007 from healthy women (n=1–9 yearly for 1987–2001, n=15 from 2006, and n=10 from 2007), possible time trends of six PFAAs were assessed. Time trends were evaluated for the entire study period, as well as for three sub-periods. As seen in previous studies, levels of perfluorohexane sulfonate (PFHxS), PFOS, and PFOA peaked during the middle time period (1990–2000), with medians of 0.98ngmL−1, 18.06ngmL−1, and 3.73ngmL−1, respectively. However, levels of perfluorononanic acid (PFNA), perfluorodecanic acid (PFDA), and perfluoroundecanoic acid (PFUnDA) increased over the whole study period and most markedly so after year 2000, with medians of 0.73ngmL−1, 0.28ngmL−1, and 0.24ngmL−1, respectively, during the last study period.

Motivated message processing: How motivational activation influences resource allocation, encoding, and storage of TV messages

This paper investigates differences in overtime processing of television messages with three types of emotional trajectories—those which begin neutral and become negative, begin neutral and become positive and begin neutral and become equally positive and negative. The limited capacity model of motivated mediated message processing is used to predict how the type of emotional content influences real-time activation of the appetitive and aversive motivational systems which then alter concurrent and subsequent message processing. Results show that during the first time period, when motivational activation is low, more resources are allocated to coactive and positive compared to negative messages supporting the positivity offset hypothesis. In the middle time period, when activation is moderate, more resources are allocated to negative than to positive messages, supporting the negativity bias hypothesis. Further, the different patterns of motivational activation do result in different patterns of messages processing. During positive messages, encoding increases and storage decreases over time. During negative messages, encoding decreases and storage increases overtime. During coactive messages initial encoding and storage are high though both decrease slightly over time.

A sliding time window heuristic for open pit mine block sequencing

The open pit mine block sequencing problem (OPBS) seeks a discretetime production schedule that maximizes the net present value of the orebody extracted from an open-pit mine. This integer program (IP) discretizes the mine’s volume into blocks, imposes precedence constraints between blocks, and limits resource consumption in each time period. We develop a “sliding time window heuristic” to solve this IP approximately. The heuristic recursively defines, solves and partially fixes an approximating model having: (i) fixed variables in early time periods, (ii) an exact submodel defined over a “window” of middle time periods, and (iii) a relaxed submodel in later time periods. The heuristic produces near-optimal solutions (typically within 2% of optimality) for model instances that standard optimization software fails to solve. Furthermore, it produces these solutions quickly, even though our OPBS model enforces standard upper-bounding constraints on resource consumption along with less standard, but important, lower-bounding constraints.

Measurement of Displacement Vector of Grains in Polycrystalline ZrO2 during High-temperature Deformation

High-temperature tensile tests were repeatedly conducted for a TZP specimen at 1, 400°C in air at intervals of about 2% of the true plastic strain up to 17.4%. After each deformation, displacement vectors of the specified 760 grains were measured from their position vectors obtained by FE-SEM micrographs. In a short time period during plastic deformation, grains moved gradually turing to the tensile axis in a zigzag way. At an early stage of deformation, the length of displacement vector distributed in a wide range because of their initial configuration after sintering. Further plastic deformation, however, grains tended to have their own movements depending on the constraint of the surroundings. In a middle time period during plastic deformation, a group of grains moved to the same direction so that several domains were formed. However, the domains disappeared due to constraint by the surrounding matrix, and other domains were formed by re-combination of grains. In a long time period during plastic deformation, grains seemed to be moving along path lines of a non-compressive fluid subjected to uniaxial tensile loading.

The Effect of Hatchery Spawning Protocols on Coho Salmon Return Timing in the Cowlitz River, Washington

AbstractWe compared the pre‐ and posthatchery return times of adult coho salmon Oncorhynchus kisutch on the Cowlitz River, Washington, after 30 years of hatchery operation. In addition, at the Cowlitz Salmon Hatchery in fall 1998, 1999, and 2000, we differentially tagged juveniles for release in 1999, 2000, and 2001 that were produced from broodstock originating from early (August to mid‐October), middle (mid‐October through November), and late (December and thereafter) time arrival windows to determine the fidelity of adult return time distribution to the window of origin. We found that posthatchery mean and median coho salmon adult return times were delayed about 2 weeks compared with prehatchery conditions, that October–November returns increased from 46% to 81% after hatchery operation, that a mean of 57% of 3‐year‐old adult fish returned in the return time window of origin, and that many of the early‐ and late‐origin fish returned in the middle time period. A mean of 70.4% of 2‐year‐old jacks from all releases returned in the middle return window. Much of the increase in October–November returns was probably due to a hatchery production emphasis of the middle‐returning fish. We recommend that broodstock be accumulated at historically proportional rates with respect to run timing, which may require additional adult holding ponds at the hatchery.

Effect of Time of Artificial Insemination on Pregnancy Rates, Calving Rates, Pregnancy Loss, and Gender Ratio After Synchronization of Ovulation in Lactating Dairy Cows

In order to assess the optimal time of artificial insemination (AI) in relation to ovulation, lactating dairy cows (n = 732) from herds with rolling herd averages of 9980 to 11,800kg from three milkings per day were randomly assigned to five groups by stage of lactation and parity. Ovulation was synchronized by administration of GnRH followed 7 d later with PGF2α followed 2 d later with a second treatment with GnRH. Cows were inseminated at 0, 8, 16, 24, or 32h after the second injection of GnRH (ovulation occurs between 24 and 32h after GnRH). Pregnancy diagnoses were performed by ultrasound at 25 to 35 d post-AI. Pregnancy rates per AI were similar for the groups inseminated at 0, 8, 16, and 24h and lower for the group inseminated at 32h. A significant quadratic effect of treatment suggests that the middle time periods (8, 16, and 24h) may produce the greatest pregnancy rate per AI. However, the group inseminated at 0h had lowest pregnancy loss, and the group inseminated at 32h tended to have the greatest pregnancy loss compared with that of the other groups. The calving rate was similar between the groups inseminated at 0, 8, 16, and 24h and lower in the group inseminated at 32h. The time of AI also appeared to affect gender of calf: cows bred at 0 and 32h having a higher percentage of female offspring. In conclusion, there appears to be substantial flexibility in the time of AI after the second injection of GnRH, and lower reproductive rates were observed only when AI was after the time of ovulation.