Negative / Null Result ReportOpen accessComputer Science
C. Abel, N. J. Ayres, G. Ban et al. · 2017 · arXiv
We report on a search for ultra-low-mass axion-like dark matter by analysing the ratio of the spin-precession frequencies of stored ultracold neutrons and $^{199}$Hg atoms for an axion-induced oscillating electric dipole moment of the neutron and an axion-wind spin-precession effect. No signal consistent with dark matter is observed for the axion mass range $10^{-24}~\textrm{eV} \le m_a \le 10^{-17}~\textrm{eV}$. Our null result sets the first laboratory constraints on the coupling of axion dark matter to gluons, which improve on astrophysical limits by up to 3 orders of magnitude, and also im
Negative / Null Result ReportOpen accessPhysics
Diego F. Torres, Stephen Reucroft, Olaf Reimer et al. · 2003 · arXiv
With the aim of testing recent claims for a particularly strong correlation between ultra-high energy cosmic rays (UHECRs), observed with the AGASA and the Yakutsk experiments, and a sample of BL Lacertae (BL Lacs), we here conduct a blind statistical assessment. We search for associations between the same set of BL Lac objects and the arrival directions of 33 relevant UHECRs observed with the Haverah Park and the Volcano Ranch experiments. Within the accuracy of angle determination, there are no positional coincidences. The probability that this null result arises as a statistical fluctuation
Negative / Null Result ReportOpen accessPhysics
P. B. Jones · 2008 · arXiv
Calculations have been made of fall-back disk heating by the pulsar wind as distinct from the soft X-rays emitted by the neutron-star surface. The relation between these heating rates and measured near-infrared fluxes in the K and Ks bands places severe constraints on the inner radii of any fall-back disks that may be present in radio pulsars and in some anomalous X-ray pulsars. The lower limits found are so large that the disks concerned can have no significant effect on pulsar spin-down.
Negative / Null Result ReportOpen accessPhysics
Cristina Bena, Leon Balents · 2001 · arXiv
We study the effect of electron-electron backscattering interactions on spin transport in a quantum wire. Even if these interactions have no significant effect on charge transport, they strongly influence the transport of spin. We use the quantum Boltzmann equation in the collision approximation to derive equations of motion for spin current and magnetization. In the limit of small perturbations from equilibrium, we explain the existence of `precessional' and `diffusive' behaviors. We also discuss the low-temperature non-linear decay of an uniform spin current outside the hydrodynamic regime.
Negative / Null Result ReportOpen accessComputer Science
Tsutomu Kobayashi · 2006 · arXiv
We study the spectrum of gravitational waves generated from inflation in the Randall-Sundrum braneworld. Since the inflationary gravitational waves are of quantum-mechanical origin, the initial configuration of perturbations in the bulk includes Kaluza-Klein quantum fluctuations as well as fluctuations in the zero mode. We show, however, that the initial fluctuations in Kaluza-Klein modes have no significant effect on the late time spectrum, irrespective of the energy scale of inflation and the equation of state parameter in the post-inflationary stage. This is done numerically, using the Wron
Negative / Null Result ReportOpen accessEconomics, Econometrics and Finance
Claudiu Albulescu · 2020 · arXiv
This paper investigates the effect of the novel coronavirus and crude oil prices on the United States (US) economic policy uncertainty (EPU). Using daily data for the period January 21-March 13, 2020, our Autoregressive Distributed Lag (ARDL) model shows that the new infection cases reported at global level, and the death ratio, have no significant effect on the US EPU, whereas the oil price negative dynamics leads to increased uncertainty. However, analyzing the situation outside China, we discover that both new case announcements and the COVID-19 associated death ratio have a positive influe
Negative / Null Result ReportOpen accessPhysics
Takashi Hamana · 1998 · arXiv
Weyl focusing effects on the image magnifications are investigated by using the multiple gravitational lens theory. We focus on the gravitational lensing effects due to the small scale virialized objects, such as galaxies and clusters of galaxies. We consider a simple model of an inhomogeneous universe. The matter distribution in the universe is modeled by randomly distributed isothermal objects. We found that, for the majority of the random lines of sight, the Weyl focusing has no significant effect and the image magnification of a point like source within redshift of 5 is dominated by the Ri
Negative / Null Result ReportOpen accessPhysics
Sarbani Basu, H. M. Antia · 2004 · arXiv
Recent analyses of solar photospheric abundances suggest that the oxygen abundance in the solar atmosphere needs to be revised downwards. In this study we investigate the consequence of this revision on helioseismic analyses of the depth of the solar convection zone and the helium abundance in the solar envelope and find no significant effect. We also find that the revised abundances along with the current OPAL opacity tables are not consistent with seismic data. A significant upward revision of the opacity tables is required to make solar models with lower oxygen abundance consistent with sei
Negative / Null Result ReportOpen accessComputer Science
Thomas M. Breuel · 2015 · arXiv
LSTM (Long Short-Term Memory) recurrent neural networks have been highly successful in a number of application areas. This technical report describes the use of the MNIST and UW3 databases for benchmarking LSTM networks and explores the effect of different architectural and hyperparameter choices on performance. Significant findings include: (1) LSTM performance depends smoothly on learning rates, (2) batching and momentum has no significant effect on performance, (3) softmax training outperforms least square training, (4) peephole units are not useful, (5) the standard non-linearities (tanh a
Negative / Null Result ReportMedicine
Makkar RR, Chakravarty T, Gupta A et al. · 2025 · Journal of the American College of Cardiology
Background In the ACURATE IDE (Safety and Effectiveness Study of ACURATE Valve for Transcatheter Aortic Valve Replacement) randomized controlled trial, ACURATE neo2 failed to show noninferiority to commercially available balloon-expandable…
View details →DOI: 10.1016/j.jacc.2025.05.011 Negative / Null Result ReportOpen accessPhysics
Saloome Siavoshi, Ashish V. Orpe, Arshad Kudrolli · 2005 · arXiv
We investigate the effective friction encountered by a mass sliding on a granular layer as a function of bed thickness and boundary roughness conditions. The observed friction has minima for a small number of layers before it increases and saturates to a value which depends on the roughness of the sliding surface. We use an index-matched interstitial liquid to probe the internal motion of the grains with fluorescence imaging in a regime where the liquid has no significant effect on the measured friction. The shear profiles obtained as a function of depth show decrease in slip near the sliding
Negative / Null Result ReportOpen accessComputer Science
Amjad Ashoorioon, Mohammad Bagher Jahani Poshteh, Robert B. Mann · 2022 · arXiv
Accelerating supermassive black holes, connected to cosmic strings, could contribute to structure formation and get captured by galaxies if their velocities are small. This would mean that the acceleration of these black holes is small too. Such a slow acceleration has no significant effect on the shadow of such supermassive black holes. We also show that, for slowly accelerating black holes, the angular position of images in the gravitational lensing effects do not change significantly. We propose a method to observe the acceleration of these black holes through the gravitational lensing. The
Negative / Null Result ReportOpen accessPhysics
K. Langanke, G. Martinez-Pinedo, B. Mueller et al. · 2007 · arXiv
Based on the shell model for Gamow-Teller and the Random Phase Approximation for forbidden transitions, we have calculated reaction rates for inelastic neutrino-nucleus scattering (INNS) under supernova (SN) conditions, assuming a matter composition given by Nuclear Statistical Equilibrium. The rates have been incorporated into state-of-the-art stellar core-collapse simulations with detailed energy-dependent neutrino transport. While no significant effect on the SN dynamics is observed, INNS increases the neutrino opacities noticeably and strongly reduces the high-energy tail of the neutrino s
Negative / Null Result ReportOpen accessComputer Science
Samir D. Mathur · 2019 · arXiv
The vacuum must contain virtual fluctuations of black hole microstates for each mass $M$. We observe that the expected suppression for $M\gg m_p$ is counteracted by the large number $Exp[S_{bek}]$ of such states. From string theory we learn that these microstates are extended objects that are resistant to compression. We argue that recognizing this `virtual extended compression-resistant' component of the gravitational vacuum is crucial for understanding gravitational physics. Remarkably, such virtual excitations have no significant effect for observable systems like stars, but they resolve tw
Negative / Null Result ReportOpen accessPhysics
L. S. R. Cavalcante, D. R. da Costa, G. A. Farias et al. · 2021 · arXiv
The effect of an external in-plane electric field on neutral and charged exciton states in two-dimensional (2D) materials is theoretically investigated. These states are argued to be strongly bound, so that electron-hole dissociation is not observed up to high electric field intensities. Trions in the anisotropic case of monolayer phosphorene are demonstrated to especially robust under electric fields, so that fields as high as 100 kV/cm yield no significant effect on the trion binding energy or probability density distribution. Polarizabilities of excitons are obtained from the parabolicity o
Negative / Null Result Report
Katsuhiko Naruse, Itsuko Okada, Masahiko Ogawa et al. · 2020 · International Journal of Gynecology & Obstetrics
Intra‐anal swabbing for GBS in pregnant women did not improve the detection rate compared to perianal swabbing, but increased the detection of ESBL‐producing E.coli .
View details →DOI: 10.1002/ijgo.13238 Negative / Null Result Report
Mark W. Clark · 2021 · Science of Law
The purpose of this study is to analyze men who have preyed on prostitutes and determine if similarities exist between the offenders who used the Internet to find sexual partners with sexual killers who did not utilize the Internet. We…
View details →DOI: 10.55284/76 Negative / Null Result ReportOpen accessPhysics
Tanech Klangburam, Chakrit Pongkitivanichkul · 2025 · arXiv
We investigate the effects of the ALP-mediated dark matter (DM) model on neutron star properties using the Quantum Hadrodynamics model (QHD). Using the relativistic mean-field approximation with the QHD-ALP-DM framework, we compute the equation of state (EoS) of neutron stars. Based on our previous study, we find that typical ALP parameter values have no significant effect on the EoS. We then explore various parametrizations of this model by varying the DM Fermi momentum, $q_f$, and DM mass, $m_χ$. Our results show that increasing $q_f$ or $m_χ$ shifts the energy density to higher values while
Negative / Null Result ReportOpen accessEconomics, Econometrics and Finance
Misha Perepelitsa · 2022 · arXiv
In this paper we give an elementary analysis of economics of Bitcoin that combines the transaction demand by the consumers and the supply of hashrate by miners. We argue that the decreasing block reward will have no significant effect on the exchange rate (price) of Bitcoin and thus the network will be transitioning to a regime where transaction fees will play a bigger part of miners' revenue. We consider a simple model where consumers demand bitcoins for transactions, but not for hoarding bitcoins, and we analyze market equilibrium where the demand is matched with the hashrate supplied by min
Negative / Null Result ReportOpen accessEngineering
Rancy Chepchirchir, Jill Sunday, Raymond Confidence et al. · 2025 · arXiv
In Sub-Saharan Africa (SSA), the utilization of lower-quality Magnetic Resonance Imaging (MRI) technology raises questions about the applicability of machine learning methods for clinical tasks. This study aims to provide a robust deep learning-based brain tumor segmentation (BraTS) method tailored for the SSA population using a threefold approach. Firstly, the impact of domain shift from the SSA training data on model efficacy was examined, revealing no significant effect. Secondly, a comparative analysis of 3D and 2D full-resolution models using the nnU-Net framework indicates similar perfor
Negative / Null Result ReportOpen accessPhysics
Xiao-ke xu, Jie Zhang, Ping Li et al. · 2011 · arXiv
Traditionally, there is no evidence suggesting that there are strong ties between the rich-club property and the function of complex networks. In this study, we find that whether a very small portion of rich nodes connected to each other or not can strongly affect the frequency of occurrence of basic building blocks (motif) within networks, and therefore the function, of a heterogeneous network. Conversely whether a homogeneous network has a rich-club property or not generally has no significant effect on its structure and function. These findings open the possibility to optimize and control t
Negative / Null Result ReportOpen accessPhysics
Vikrant Yadav, Rajpal, Pardeep et al. · 2024 · arXiv
In this letter, we report the observational constraints on a Bianchi type I anisotropic extension of $w$CDM model with spatial curvature from observational data including Baryon Acoustic Oscillations (BAO), Cosmic chronometers (CC), Big Bang nucleosynthesis (BBN), Pantheon+ (PP) compilation of SNe Ia and SH0ES Cepheid host distance anchors. The anisotropy is found to be of the order $10^{-13}$, which interplay with spatial curvature to reduce $H_0$ tension by $\sim 1σ$ as found in the analyses with BAO+CC+BBN+PP combination of data, while no significant effect of anisotropy is observed with BA
Negative / Null Result ReportOpen accessPhysics
Andrey A. Kistanov, Yongqing Cai, Kun Zhou et al. · 2016 · arXiv
We investigate the electronic structure and chemical activity of rippled phosphorene induced by large compressive strains via first-principles calculation. It is found that phosphorene is extraordinarily bendable, enabling the accommodation of ripples with large curvatures. Such highly rippled phosphorene shows a strong anisotropy in electronic properties. For ripples along the armchair direction, the band gap changes from 0.84 to 0.51 eV for the compressive strain up to -20% and further compression shows no significant effect, for ripples along the zigzag direction, semiconductor to metal tra
Negative / Null Result ReportOpen accessEconomics, Econometrics and Finance
Markus Dertwinkel-Kalt, Max R. P. Grossmann · 2025 · arXiv
When environmental regulations are unpopular, policymakers often attribute resistance to information frictions and poor communication. We test this idea in the context of a major climate policy: Germany's Heating Law of 2023, which mandates the phase-out of fossil fuel heating. Through a survey experiment with property owners, we examine whether providing comprehensive information about the regulation's costs, requirements, and timeline affects adoption decisions and policy support. Despite successfully increasing factual knowledge, information provision has no significant effect on intended t
Negative / Null Result ReportOpen accessBiology (General)
Qiaoli Wang, Wenpei Wang, Yonghui Wang et al. · 2024 · Journal of Fungi
Manganese is one of the trace elements necessary for organisms to maintain normal biological activities and is also a cofactor for manganese superoxide dismutase (Mn-SOD) and manganese peroxidase (MnP). In order to find a simple and effective method to rejuvenate the degenerated V. volvacea strains, we explored the effect of the exogenous addition of MnSO 4 on the antioxidant vigour and productivity of degenerated strains of V. volvacea . The results showed that the exogenous MnSO 4 had no significant effect on the non-degenerated strain T0, but it could effectively increase the mycelial growt
View details →DOI: 10.3390/jof10120825 Negative / Null Result ReportOpen accessScience
Karlos Edmundo Orozco Durán, José Segura Correa, Jessica Herrera Ojeda et al. · 2022 · Nova Scientia
The aim of the study was to evaluate the effect of body condition score (BCS) at lambing over the resumption of ovarian and estrous postpartum activity in lactating Pelibuey ewes. Twenty ewes were assigned to two groups, according to the BCS at lambing: Low BCS (LBC, n = 10) and High BCS (HBC, n = 10). Ovarian and estrous activities were daily monitored from day 3 postpartum until the first estrous or 90 days postpartum. Continuous variables were analyzed using Student´s t test and binary responses with the exact Fisher test. No significant effect of BCS at lambing on ewes in estrous, lambing
View details →DOI: 10.21640/ns.v14i28.2965 Negative / Null Result ReportOpen accessEnvironmental sciences
Chandini Palakkunnel Kuttappan, Sasankan Prasanth Narayanan, Syamkumar Reghu Nandanan Pillai et al. · 2025 · Natural Built Social Environment Health
This study assessed the toxic effects of pesticide exposure on four earthworm species: Perionyx excavatus Perrier, 1872; Megascolex konkanensis Fedarb, 1898; Dichogaster affinis (Michaelsen, 1890); and Metaphire houlleti (Perrier, 1872). The organisms were exposed to pesticide-treated soil. Biomass reduction, immunotoxicity, and enzyme biomarkers were used as endpoints. Among the tested species, M. konkanensis, a native species, appeared more sensitive than the others. In biomass tests, chlorpyrifos showed no significant effect on final body mass (p > 0.05). P. excavatus showed a significant r
View details →DOI: 10.63095/nbseh.25.850535 Negative / Null Result ReportOpen accessChemistry
Vincent J. Farage, Désimir Janjic · 1981 · CHIMIA
In certain cases, and particularly for the BrO3-/Ce4+/malonic acid system, oxygen seems to inhibit oscillations and the mechanical stirring in a N2 atmosphere has no significant effect on the oscillations. However, for the BrO3-/Ce4+/Cyclohexanon and BrO3-/Ce4+/Cyclopentanon systems under specific experimental conditions, stirring plays a determining part and oxygen has no notable effect on the oscillations.
View details →DOI: 10.2533/chimia.1981.289 Negative / Null Result ReportOpen accessAccounting. Bookkeeping
Hutapea Lastiar Hutapea, Aristanti Widyaningsih · 2017 · Jurnal ASET (Akuntansi Riset)
Abstract. The variables tested in the study consist of Good Government Governance measured by the rank of Indonesia Governance Index (IGI) and the size of the legislative by using the number of members of the provincial parliament, and also local government performance measured by three proxies, the GDP per capita, Poverty Rates, and independence Ratios. The study is conducted in 33 provinces in Indonesia in 2012. The results show that there is no significant effect of good government governance on local government performance by proxy of GDP per capita. There is significant impact of good gov
View details →DOI: 10.17509/jaset.v9i1.5446 Negative / Null Result ReportOpen accessEngineering (General). Civil engineering (General)
Tkachenko Egor M., Zaitsev Dmitry V. · 2016 · MATEC Web of Conferences
Intensively evaporating liquid films moving under the action of the cocurrent gas flow in a microchannel are promising for the use in modern cooling systems of semiconductor devices with high local heat release. This work has studied the dependence of the critical heat flux on the inclination angle of the channel. It has been found that the inclination angle in the plane parallel to the flow has no significant effect on the critical heat flux. Whereas the inclination angle in the plane perpendicular to the flow, on the contrary, significantly changes the value of the critical heat flux. Howeve
View details →DOI: 10.1051/matecconf/20167201114 