Record Energetics for an Inertial Fusion Implosion at NIF

Inertial confinement fusion seeks to create burning plasma conditions in a spherical capsule implosion, which requires efficiently absorbing the driver energy in the capsule, transferring that energy into kinetic energy of the imploding DT fuel and then into internal energy of the fuel at stagnation. We report new implosions conducted on the National Ignition Facility (NIF) with several improvements on recent work [Phys. Rev. Lett. 120, 245003 (2018)PRLTAO0031-900710.1103/PhysRevLett.120.245003; Phys. Rev. E 102, 023210 (2020)PRESCM2470-004510.1103/PhysRevE.102.023210]: larger capsules, thicker fuel layers to mitigate fuel-ablator mix, and new symmetry control via cross-beam energy transfer; at modest velocities, these experiments achieve record values for the implosion energetics figures of merit as well as fusion yield for a NIF experiment.

62 Investigating differences in gene expression between invitro-produced bovine embryos and parthenotes

Parthenogenic activation allows for the development of an oocyte without male gamete contribution and may serve as a suitable model for understanding maternal and paternal contributions during development. In the bovine, parthenotes lack the ability to survive to term once transferred into females. The goal of this study was to investigate the gene expression profile at the blastocyst stage in parthenotes and embryos by characterising expression of developmentally important genes, such as markers for pluripotency (OCT4, NANOG), hypoblast (GATA6), epiblast (SOX2), trophectoderm (CDX2), and maternal-embryo communication (IFNT2). To test this, IVM oocytes were either fertilized to a bull with known fertility invitro or activated. To activate, oocytes were denuded, and placed in ionomycin calcium salt for 5min. They were incubated for 3h in 6-(dimethylamino)purine (6-DMAP) and placed in synthetic oviductal fluid (SOF). Putative zygotes and activated oocytes were cultured in SOF for 8 days. Cleavage (at least one cellular division) was recorded on Day 3 and development to the blastocyst stage was recorded on Day 8 after insemination or activation. Cleavage rate was 85.9% and 83.2% for parthenotes and embryos, respectively. Both groups produced a similar blastocyst rate, 32.3% for parthenotes and 33.7% for embryos. On Day 8, blastocyst stage parthenotes and embryos were collected. Data were analysed by ANOVA (Tukey HSD post hoc test) using the GLM procedure of SAS version 9.4. Pools of 5 embryos or parthenotes (3 replicates) were flash frozen and stored until RNA isolation (PicoPure™ RNA Isolation Kit). Real-time PCR was used for quantification of gene expression. Genes were analysed relative to a housekeeping gene, GAPDH. There was no difference in gene expression detected for OCT4 (P=0.25), NANOG (P=0.11), GATA6 (P=0.32), SOX2 (P=0.25), or IFNT2 (P=0.52). Expression of CDX2 was lower in the parthenotes than the embryos (P=0.05). In a second experiment, the proteins GATA6, NANOG, and CDX2 were immunolocalized in 17 parthenotes and 15 embryos. Fixed embryos were permeabilized, blocked, and placed in primary antibodies overnight. After, they were placed into the secondary antibody for 1h, followed by nuclear stain. There was a decreased mean intensity of CDX2 in the parthenotes compared to embryos (P=0.005). No difference (P>0.05) in GATA6 or NANOG was observed between the 2 groups. The ratio of inner cell mass to trophectoderm was higher (P=0.04) in the parthenotes (2.5±0.23) than in the embryos (1.7±0.25). Here we analysed and confirmed the expression of developmentally important genes at the blastocyst stage in embryos and parthenotes. CDX2, a marker of the trophectoderm that will later give rise to the placenta, was downregulated in parthenotes. This highlights the importance of the contribution of the paternal genome to development. Further research is necessary to elucidate the ability of the parthenotes to establish and maintain pregnancy. This research was supported by the National Needs Fellowship funded by USDA NIFA Grant 2019-38420-28972.

63 Effect of sire conception rate on bovine early embryo development

Currently, the only measure of sire fertility in the bovine is sire conception rate (SCR), which is determined by Day 70 pregnancy diagnosis and not reflective of early embryo development. Therefore, this study aimed to establish the relationship between SCR and early embryo development. In the first experiment, 65 sires of negative (<−1, n=25), average (−1 to 1, n=19), and high (> +1, n=21) SCR were characterised for their ability to produce embryos using an invitro embryo production (IVP) system. For each sire, 100 cumulus–oocyte complexes (COCs) were used. COCs were matured for 22h, fertilized by co-incubation with sperm selected from density gradient centrifugation for 18h, and then placed in culture medium. A sire of known IVP performance was used as a control in each run. Cleavage and blastocyst rates (BL) were measured on Days 3 and 8 post-insemination, respectively. Photographs were taken on Days 3, 5, and 8 to identify arrest stages of non-blastocyst embryos. Sires were ranked based on their blastocyst rate and grouped into quartiles for statistical analysis. Differences in BL were determined by ANOVA using sire, IVP run, and a sire×IVP run interaction. In addition, the correlation between SCR and BL was determined. All data were analysed using SAS software version 9.4 (SAS Institute Inc.). Mean BL between each quartile was significant (P<0.05), with rates ranging from 8 to 22% and 32 to 62% for the lowest and highest quartile, respectively. There was no correlation (P=0.90) between SCR and BL. Arrest stage was measured by subtracting the number of Day-8 blastocysts from, first, embryos that were morulas on Day 5, and then embryos that were 8- to 16-cell stage embryos on Day 5. This method is based on the assumption that embryos closer to the blastocyst stage on Day 5 are more likely to contribute to the Day 8 blastocyst population. The most frequent arrest stage was the 4- to 6-cell stage (39/52 sires). It has been shown that decreased rates of autophagy are associated with embryonic arrest at the 4- to 8-cell stage in humans, leading us to investigate this mechanism in the second experiment. Select high (n=3) and low (n=4) performing sires identified in experiment 1 were used to generate 4- to 6-cell embryos, and autophagy rates were measured using live immunofluorescence with CYTO-ID autophagy dye (n=20 embryos/sire). The mean fluorescent intensity of each embryo was divided by the number of cells within the embryo. Differences in autophagy between high and low sires were determined by ANOVA using SAS. Interestingly, low-performing sires had a significantly higher autophagy rates than high-performing sires (77.8±3.1 vs. 50.0±3.5). This could indicate that embryos produced with low-performing sires had higher levels of stress than their counterparts. In summary, the effect of sire on embryonic development seems to be independent of the SCR classification. The most common arrest stage observed is the 4- to 6-cell stage, right before embryonic genome activation. Further research is required to elucidate the mechanisms by which sires influence pre-implantation development. This research was supported by USDA-NIFA AFRI Competitive Grant No. 2019-67015-28998.

96 Validation of the candidate mutation responsible for embryonic lethality in Holstein haplotype 2 carriers

Holstein haplotype 2 (HH2) is embryonic lethal and carried by 1.21% of the US Holstein population. Using next-generation sequencing, we identified a high-impact frameshift mutation in intraflagellar protein 80 (IFT80) as the putative causal mutation. In bovine embryos, IFT80 expression begins at the 8-cell stage and decreases by the blastocyst stage. We hypothesised that the loss of function of IFT80 early in development causes the lethal phenotype. The aim of this study was to mimic the mutation observed invivo using a CRISPR-Cas9 approach to determine its effect on embryo development. Two guide RNAs (gRNAs) were designed to disrupt exon 11 (Ex11), one before and one after the known IFT80 mutation site, creating a 317-nucleotide (nt) cut to facilitate genotyping. Then, gRNAs annealed to a tracr-Cas9mRNA complex were delivered to 1-cell embryos by microinjection. Each replicate contained control embryos injected with only Cas9mRNA and treated embryos injected with gRNAs targeting IFT80. Embryos from each group were collected at the 8-cell stage for genotyping and gene expression analysis (n=47), or on Day 8 to validate genotypes of embryos left to develop (n=50). DNA sequences containing gRNA target sequences were amplified and visualised on an agarose gel. IFT80 expression was determined in biallelic embryos (n=13) using quantitative PCR and normalized to GAPDH. Primers were designed for the transcript regions before and after gRNAs target sequences, exons 9 and 12, respectively. Expression data were analysed using SAS software (v. 9.4; SAS Institute Inc.) using PROC GLM and LSMEANS to determine expression differences. Biallelic samples (n=9) were Sanger-sequenced (SS) and aligned with the reference sequence to determine exact cut sites. Protein amino acid (AA) sequences were predicted using SS data. Protein models were constructed using the I-Tasser platform, and then aligned and visualised using PyMol 2.4. Biallelic edits showed a significant decrease in exon 12 expression (P<0.05), and no difference in exon 9 compared with controls (P>0.05), indicating that the transcript was severely affected downstream of the edited sites. The reference protein model contained 777 AA, whereas the biallelic sample with the most accurate cut sites yielded a 385-AA protein, indicating that the mutation severely altered protein conformation and possible function. Embryos injected with CRISPR-Cas9 targeting Ex11 arrested at the 8-cell stage and failed to form blastocysts. Day 8 embryos were genotyped (n=24) and 58% were biallelic, 21% were monoallelic, and 21% appeared wild-type. Given the high rate of edits, the observed embryonic arrest is likely due to disruption of IFT80, and wild-type embryos may contain small edits not visible by gel. In conclusion, generation of CRISPR-Cas9 IFT80 knockouts demonstrated that the frameshift mutation in Ex11 results in a seemingly nonfunctional protein that is responsible for the embryonic lethality seen in HH2 carriers. Future research is needed to determine how IFT80 regulates embryonic development. This research was supported by USDA-NIFA National Needs Fellowship, USDA-NIFA AFRI Grant No. 2019-67015-28998.

COVID-19 in Kidney Transplant Patients From a Large UK Transplant Center: Exploring Risk Factors for Disease Severity

Background

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has raised concern for the health of immunocompromised individuals, who are potentially at higher risk of more severe infection and poorer outcomes. As a large London transplant center serving a diverse patient population, we report the outcomes of SARS-CoV-2 infection in our cohort of 2848 kidney and/or pancreas transplant patients.

Methods

Data were obtained retrospectively for all transplant patients who attended hospital during the peak of the pandemic and had a positive nasopharyngeal SARS-CoV-2 test.

Results

Sixty-six patients were found to be positive for SARS-CoV-2. Twenty percent were treated as outpatients, 59% were admitted to the general ward, and 21% required intensive care. Treatment consisted of reduced immunosuppression, antibiotics for pneumonia or sepsis, and other supportive treatments. Within our cohort, 12 patients died (18%), with an overall mortality of 0.4%. Predictive risk factors for COVID-19 severity were explored.

Conclusions

Severe disease was associated with lower hemoglobin prior to COVID-19 diagnosis and lower lymphocyte count at the time of diagnosis but not age, sex, ethnicity, or preexisting comorbidities. Lower glomerular filtration rate and higher C-reactive protein were associated with more severe disease. Despite no use of hydroxychloroquine, azithromycin, antiviral, or immunomodulatory medications, our mortality rate (kidney and pancreas transplant patients) is similar to current international rates.

eV-Scale Sterile Neutrino Search Using Eight Years of Atmospheric Muon Neutrino Data from the IceCube Neutrino Observatory

The results of a 3+1 sterile neutrino search using eight years of data from the IceCube Neutrino Observatory are presented. A total of 305 735 muon neutrino events are analyzed in reconstructed energy-zenith space to test for signatures of a matter-enhanced oscillation that would occur given a sterile neutrino state with a mass-squared differences between 0.01 and 100  eV^{2}. The best-fit point is found to be at sin^{2}(2θ_{24})=0.10 and Δm_{41}^{2}=4.5  eV^{2}, which is consistent with the no sterile neutrino hypothesis with a p value of 8.0%.

Characteristics of the Diffuse Astrophysical Electron and Tau Neutrino Flux with Six Years of IceCube High Energy Cascade Data

We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010-2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated (∼90%) by electron and tau flavors. The flux, observed in the sensitive energy range from 16 TeV to 2.6 PeV, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be γ=2.53±0.07 and a flux normalization for each neutrino flavor of ϕ_{astro}=1.66_{-0.27}^{+0.25} at E_{0}=100  TeV, in agreement with IceCube's complementary muon neutrino results and with all-neutrino flavor fit results. In the measured energy range we reject spectral indices γ≤2.28 at ≥3σ significance level. Because of high neutrino energy resolution and low atmospheric neutrino backgrounds, this analysis provides the most detailed characterization of the neutrino flux at energies below ∼100  TeV compared to previous IceCube results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p value ≥0.06). The sizable and smooth flux measured below ∼100  TeV remains a puzzle. In order to not violate the isotropic diffuse gamma-ray background as measured by the Fermi Large Area Telescope, it suggests the existence of astrophysical neutrino sources characterized by dense environments which are opaque to gamma rays.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

AB0557 CO-EXISTENCE OF SYSTEMIC SCLEROSIS HALLMARK AUTOANTIBODIES ASSOCIATES WITH DISTINCT CLINICAL PHENOTYPE

Background:

Systemic sclerosis (SSc) is typically manifests with distinct SSc-specific antibodies (SSc-Abs): anti-topoisomerase I (ATA), anti-centromere (ACA), anti-RNA polymerase III (ARA), anti-U3RNP (u3RNP), anti-U1RNP (U1RNP), anti-PmScl (PmScl), anti-Ku (Ku) and anti-Th/T0 (Th/T0), each being characterised by different clinical features and prognosis. The presence of >1 SSc-Abs is rare with minimum data about these patients’ clinical phenotype.

Objectives:

To describe and compare the clinical features of SSc patients with >1 SSc-Ab

Methods:

The autoantibody profiles of 2799 SSc patients from February 2001 to June 2017 were retrospectively reviewed. Patients with >1 SSc-Abs were identified. Clinical features were collected and compared to historical cohorts of SSc patients with single SSc-Ab positivity. Patients were excluded if treated prior to their immunology test with rituximab, iv immunoglobulins or stem cell transplantation. Statistical analysis was performed using Fisher exact test.

Results:

72 patients (2.6%) with >1 SSc-Ab were identified. Full clinical data were available for 63 patients. 60 patients (2.1%) had double Ab positivity and 3 patients had triple Ab positivity (0.1%). 13 Ab combinations were present. U1RNP and ATA was the most frequent combination (35%), patients were significantly younger (51.38 years) than both U1RNP (58.64 years, p=0.050) and ATA (62.03 years, p=0.002) patients and more commonly of diffuse subset (dcSSc) (p=0.001 and p=0.041 respectively). Compared to ATA patients overlap features were more frequent (43% vs 15%, p=0.004) including inflammatory arthritis (p=0.025) and myositis (p=0.013) (Table 1). U1RNP and ACA had a significantly higher prevalence of pulmonary arterial hypertension compared to U1RNP (p=0.039) and ACA (p=0.022) patients, and compared to ACA patients they were younger (57.88 vs 68.75, p=0.015) with a higher incidence of myositis (p=0.001). U1RNP and ARA patients were more frequently dcSSc subtype compared to U1RNP patients (75% vs 21%, p=0.040). U1RNP and PmScl patients had a higher prevalence of myositis compared to U1RNP patients (p=0.006). ATA and ACA patients behaved similarly to ATA patients with a significantly higher prevalence of lung fibrosis (p=0.006) and myositis (p=0.041) compared to ACA. ACA and PmScl (7%) had higher prevalence of myositis compared to ACA patients (p=0.04).

Table 1. Frequency of clinical features in some of the double antibody group combinations, compared to our cohort of patients with only one of the SSc specific antibody. Significant p values (<0.05) highlighted in bold. ILD (interstitial lung disease), PAH (pulmonary arterial hypertension), SRC (scleroderma renal crisis).

Conclusion:

Coexistence of hallmark autoantibodies is exceedingly rare in SSc patients. When combined, both SSc-Abs have the potential to synergistically interact and modify the clinical phenotype.

Disclosure of Interests:

Corrado Campochiaro Speakers bureau: Novartis, Pfizer, Roche, GSK, SOBI, Kristina Clark: None declared, Lauren Host: None declared, Alper Sari: None declared, Svetlana Nihtyanova: None declared, Christopher Denton Grant/research support from: GlaxoSmithKline, CSL Behring, and Inventiva, Consultant of: Medscape, Roche-Genentech, Actelion, GlaxoSmithKline, Sanofi Aventis, Inventiva, CSL Behring, Boehringer Ingelheim, Corbus Pharmaceuticals, Acceleron, Curzion and Bayer, Voon Ong: None declared

Health resource utilization of labor induction versus expectant management

BACKGROUND

Although induction of labor of low-risk nulliparous women at 39 weeks reduces the risk of cesarean delivery compared with expectant management, concern regarding more frequent use of labor induction remains, given that this intervention historically has been thought to incur greater resource utilization.

OBJECTIVE

The objective of the study was to determine whether planned elective labor induction at 39 weeks among low-risk nulliparous women, compared with expectant management, was associated with differences in health care resource utilization from the time of randomization through 8 weeks postpartum.

STUDY DESIGN

This is a planned secondary analysis of a multicenter randomized trial in which low-risk nulliparous women were assigned to induction of labor at 39 weeks or expectant management. We assessed resource utilization after randomization in 3 time periods: antepartum, delivery admission, and discharge through 8 weeks postpartum.

RESULTS

Of 6096 women with data available, those in the induction of labor group (n = 3059) were significantly less likely in the antepartum period after randomization to have at least 1 ambulatory visit for routine prenatal care (32.4% vs 68.4%), unanticipated care (0.5% vs 2.6%), or urgent care (16.2% vs 44.3%), or at least 1 antepartum hospitalization (0.8% vs 2.2%, P < .001 for all). They also had fewer tests (eg, sonograms, blood tests) and treatments (eg, antibiotics, intravenous hydration) prior to delivery. During the delivery admission, women in the induction of labor group spent a longer time in labor and delivery (median, 0.83 vs 0.57 days), but both women (P = .002) and their neonates (P < .001) had shorter postpartum stays. Women and neonates in both groups had similar frequencies of postpartum urgent care and hospital readmissions (P > .05 for all).

CONCLUSION

Women randomized to induction of labor had longer durations in labor and delivery but significantly fewer antepartum visits, tests, and treatments and shorter maternal and neonatal hospital durations after delivery. These results demonstrate that the health outcome advantages associated with induction of labor are gained without incurring uniformly greater health care resource use.

Time-Integrated Neutrino Source Searches with 10 Years of IceCube Data

This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate the significance of an astrophysical signal from a pointlike source looking for an excess of clustered neutrino events with energies typically above ∼1  TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches. The most significant point in the northern hemisphere from scanning the sky is coincident with the Seyfert II galaxy NGC 1068, which was included in the source catalog search. The excess at the coordinates of NGC 1068 is inconsistent with background expectations at the level of 2.9σ after accounting for statistical trials from the entire catalog. The combination of this result along with excesses observed at the coordinates of three other sources, including TXS 0506+056, suggests that, collectively, correlations with sources in the northern catalog are inconsistent with background at 3.3σ significance. The southern catalog is consistent with background. These results, all based on searches for a cumulative neutrino signal integrated over the 10 years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.

Abstract P4-12-02: Age-related distress in 3352 breast cancer patients

Purpose: Age-related biopsychosocial distress in breast cancer patients has been poorly studied and understood. The breast cancer experience may be different based on chronological age, which may be a surrogate marker of biologic, psychological, social, and functional age. This study reports patient-reported biopsychosocial problem-related distress in breast cancer patients.

Methods: All new patients seen at the City of Hope breast cancer clinic undergo a validated comprehensive biopsychosocial screening prior to their first visit with a medical/surgical oncologist. This touchscreen driven technology queries patients on their physical symptoms, psychosocial concerns, informational and resource needs, interests in clinical trials, and other breast cancer specific concerns. This IRB approved study was conducted in 3,352 patients evaluated from 2009 to 2017. Screening occurred immediately prior to meeting with the physician so that the information could be integrated into the clinical encounter.

Results: The age-related groups included 268 Adolescent and young adult (AYA) patients ages 18-39, 2,244 middle aged adults 40-64 years, and 840 older adults ages 65+ years. Regardless of age, four of the top seven highly distressing problems were the same: worry about the future, side effects of treatment, sleep and fatigue. AYA patients and middle aged adults, but not older adults, identified finances and being anxious or fearful among their top five causes of distress. Middle aged adults and older adults, but not AYA patients, identified physical pain among their top seven causes of distress. Interestingly, both AYA and older adults, but not middle aged adults, identified getting information about complementary and alternative practices as a top source of distress. Although a serious problem across all age categories, thoughts of ending one's life and seriously considering taking one's life were the least common problems identified.

Conclusions: In this series with 3,352 patients, biopsychosocial concerns raised with a diagnosis of breast cancer were similar regardless of age. However, patients under the age of 65 may worry more about finances and patients over the age of 40 may worry more about physical symptoms such as pain. Both AYA patients and older adults cited distress learning about complementary and alternative practices, suggesting a need for providers to address this, especially in these patient populations. Thoughts of ending one's own life were uncommon, which is relevant in a state with the End of Life Option Act.

Citation Format: Hill A, Obenchain R, Clark K, Loscalzo M, Mortimer J. Age-related distress in 3352 breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-12-02.

Constraints on Minute-Scale Transient Astrophysical Neutrino Sources

High-energy neutrino emission has been predicted for several short-lived astrophysical transients including gamma-ray bursts (GRBs), core-collapse supernovae with choked jets, and neutron star mergers. IceCube's optical and x-ray follow-up program searches for such transient sources by looking for two or more muon neutrino candidates in directional coincidence and arriving within 100 s. The measured rate of neutrino alerts is consistent with the expected rate of chance coincidences of atmospheric background events and no likely electromagnetic counterparts have been identified in Swift follow-up observations. Here, we calculate generic bounds on the neutrino flux of short-lived transient sources. Assuming an E^{-2.5} neutrino spectrum, we find that the neutrino flux of rare sources, like long gamma-ray bursts, is constrained to <5% of the detected astrophysical flux and the energy released in neutrinos (100 GeV to 10 PeV) by a median bright GRB-like source is <10^{52.5}  erg. For a harder E^{-2.13} neutrino spectrum up to 30% of the flux could be produced by GRBs and the allowed median source energy is <10^{52}  erg. A hypothetical population of transient sources has to be more common than 10^{-5}  Mpc^{-3}  yr^{-1} (5×10^{-8}  Mpc^{-3}  yr^{-1} for the E^{-2.13} spectrum) to account for the complete astrophysical neutrino flux.