nils-herrmann/clean_scirepeval huggingface dataset:
On the Minimax Risk of Dictionary Learning

We consider the problem of learning a dictionary matrix from a number of observed signals, which are assumed to be generated via a linear model with a common underlying dictionary. In particular, we derive lower bounds on the minimum achievable worst case mean squared error (MSE), regardless of computational complexity of the dictionary learning (DL) schemes. By casting DL as a classical (or frequentist) estimation problem, the lower bounds on the worst case MSE are derived following an established information-theoretic approach to minimax estimation. The main contribution of this paper is the adaption of these information-theoretic tools to the DL problem in order to derive lower bounds on the worst case MSE of any DL algorithm. We derive three different lower bounds applying to different generative models for the observed signals. The first bound only requires the existence of a covariance matrix of the (unknown) underlying coefficient vector. By specializing this bound to the case of sparse coefficient distributions and assuming the true dictionary satisfies the restricted isometry property, we obtain a lower bound on the worst case MSE of DL methods in terms of the signal-to-noise ratio (SNR). The third bound applies to a more restrictive subclass of coefficient distributions by requiring the non-zero coefficients to be Gaussian. Although the applicability of this bound is the most limited, it is the tightest of the three bounds in the low SNR regime. A particular use of our lower bounds is the derivation of necessary conditions on the required number of observations (sample size), such that DL is feasible, i.e., accurate DL schemes might exist. By comparing these necessary conditions with sufficient conditions on the sample size such that a particular DL technique is successful, we are able to characterize the regimes, where those algorithms are optimal in terms of required sample size.

Field of study: Computer science
ElsieFour: A Low-Tech Authenticated Encryption Algorithm For Human-to-Human Communication

ElsieFour (LC4) is a low-tech cipher that can be computed by hand; but unlike many historical ciphers, LC4 is designed to be hard to break. LC4 is intended for encrypted communication between humans only, and therefore it encrypts and decrypts plaintexts and ciphertexts consisting only of the English letters A through Z plus a few other characters. LC4 uses a nonce in addition to the secret key, and requires that different messages use unique nonces. LC4 performs authenticated encryption, and optional header data can be included in the authentication. This paper defines the LC4 encryption and decryption algorithms, analyzes LC4’s security, and describes a simple appliance for computing LC4 by hand.

Field of study: Computer science, Mathematics
Bifrontal approach for clip ligation of bilateral ethmoidal dural arteriovenous fistulas: operative video.

Venous interruption through surgical clip ligation is the gold standard treatment for ethmoidal dural arteriovenous fistula (e-dAVF). Their malignant natural history is attributable to the higher predilection for retrograde cortical venous drainage. This video illustrates an e-dAVF in a 70-year-old man with progressive tinnitus and headache. Angiogram revealed bilateral e-dAVFs (Borden III-Cognard III) with one fistula draining into cavernous sinus and another to the sagittal sinus. A bifrontal craniotomy was utilized for venous interruption of both e-dAVFs. Postoperative angiography confirmed curative obliteration with no postoperative anosmia. Bilateral e-dAVFs are rare but can be safely treated simultaneously through a single craniotomy.The video can be found here: https://youtu.be/666edwKHGKc.

Field of study: Medicine
Eine neue und einfache Synthese des Dipyrazino[2,3-f:2',3'-h]-chinoxalin-Ringsystems

Es wird uber eine einstufige Synthese einer Reihe erster 2,3,6,7,10,11-hexasubstituierter Dipyrazino[2,3,-f:2′3′-h]chinoxaline 3b – i aus Benzolhexamin (1) und symmetrischen α-Diketonen 2b – i berichtet. Auserdem werden verbesserte Synthesevorschriften fur 1 und dessen Vorstufe 2,4,6-Trinitro-1,3,5-benzoltriamin mitgeteilt. 
 
 
 
A New and Simple Synthesis of the Dipyrazino[2,3-f:2′3′-h]quinoxaline Ring System 
 
 
 
A one-step synthesis of some 2,3,6,7,10,11-hexasubstituted dipyrazino[2,3-f:2′,3′-h]quinoxalines 3b – i from benzenehexamine (1) and various symmetrical α-diketones 2b – i is reported. Furthermore, improved preparations of 1 and of its precursor 2,4,6-trinitro-1,3,5-benzenetriamine are described.

Field of study: Chemistry
Silicon nanocrystal non-volatile memory for embedded memory scaling

In this paper, we present key features of silicon nanocrystal memory technology. This technology is an attractive candidate for scaling of embedded non-volatile memory (NVM). By replacing a continuous floating gate by electrically isolated silicon nanocrystals embedded in an oxide, this technology mitigates the vulnerability of charge loss through tunnel oxide defects and hence permits tunnel oxide and operating voltage scaling along with accompanied process simplifications. However, going to discrete nanocrystals brings new physical attributes that include the impact of Coulomb blockade or charge confinement, science of formation of nanocrystals of correct size and density and the role of fluctuations, all of which are addressed in this paper using single memory cell and memory array data.

Field of study: Engineering
ADMINISTRATIVE REFORM IN NEW SOUTH WALES UNDER GOVERNOR DARLING

As a governor, Ralph Darling is remembered more for his authoritarian behaviour and harsh rule than for his administrative achievements. Only recently have historians shown much awareness of the important reforms which he made in the machinery of government. Yet, although attention has been drawn to this aspect of his work it has not been adequately examined. The tendency is still to concentrate on the colourful and controversial features of his regime, pushing to one side its more mundane developments. Admittedly, there are exceptions.  Cell included an interesting section on Darling in British Colonial Administration in the Mid-Nineteenth Century, as did J. J. Eddy in Britain and the Australian Colonies. The first of these treatments is too brief, however, and the second concentrates on those aspects affected by the attempts of the British Treasury to exert more influence over colonial administration. Despite these books, the valuable thesis on the Colonial Secretary's Office by G. D. Richardson and the helpful prefaces that appear in the various guides to the records of government departments, prepared by the State Archives of New South Wales, much remains to be done. Most of the departments that existed under Darling still await detailed treatment both in themselves and in relation to the overall changes that were made between 1825 and 1831. As matters stand, there is a gap not only in what was a vital era in the administrative history of New South Wales, but also in Darling's own record. The present paper attempts to repair this omission.

Field of study: Political science
C-FOG: Life of Coastal Fog

C-FOG is a comprehensive bi-national project dealing with the formation, persistence, and dissipation (life cycle) of fog in coastal areas (coastal fog) controlled by land, marine, and atmospheric processes. Given its inherent complexity, coastal-fog literature has mainly focused on case studies, and there is a continuing need for research that integrates across processes (e.g., air–sea–land interactions, environmental flow, aerosol transport, and chemistry), dynamics (two-phase flow and turbulence), microphysics (nucleation, droplet characterization), and thermodynamics (heat transfer and phase changes) through field observations and modeling. Central to C-FOG was a field campaign in eastern Canada from 1 September to 8 October 2018, covering four land sites in Newfoundland and Nova Scotia and an adjacent coastal strip transected by the Research Vessel Hugh R. Sharp. An array of in situ, path-integrating, and remote sensing instruments gathered data across a swath of space–time scales relevant to fog life cycle. Satellite and reanalysis products, routine meteorological observations, numerical weather prediction model (WRF and COAMPS) outputs, large-eddy simulations, and phenomenological modeling underpin the interpretation of field observations in a multiscale and multiplatform framework that helps identify and remedy numerical model deficiencies. An overview of the C-FOG field campaign and some preliminary analysis/findings are presented in this paper.

Field of study: Environmental science
DIFFERENTIATION OF A PRECISE TIMING RESPONSE.

Humans, monkeys, and rats were trained by a process of successive differentiations to press a bar for at least 1.00 sec but for no longer than 1.27 sec. Initially, animals were reinforced for all responses, then a minimum duration of response was gradually differentiated, below which no responses were reinforced. Finally, a maximum duration of response was differentiated above which no responses were reinforced. The duration of response in all three species approximated the minimum duration of response necessary for reinforcement. As the duration of response necessary for reinforcement increased, so did the mean duration of response in the three species. As the maximum allowable duration decreased, further compression of the mean occurred. The fact that the acquisition of the differentiation was approximately the same in all three species is a further indication of the control reinforcement exerts on operant responding.

Field of study: Biology, Psychology
Combined effects of fluid selection and flow condensation on ejector operation in an ejector-based chiller

This work investigates the optimization of the coefficient of performance of an ejector-based chiller through changes in the two-phase flow characteristics inside the ejector using wet R134a and dry R245fa fluids. Reducing the superheat at the motive nozzle inlet results in a 12–13% increase in COP with a 14–16 K drop in driving waste heat temperature. The roles of momentum transfer, heat transfer, and two-phase flow on performance are delineated. The change in COP appears to be a combination of the choice of fluid and the effect of phase change on momentum transfer effectiveness. Larger degrees of condensation reduce momentum transfer effectiveness; however, energy savings from reduced motive superheating compensates for the effect of condensation, and causes a net increase in COP. It is recommended that ejector-based chillers be operated such that the motive nozzle inlet is near saturation, and dry fluids like R245fa are used to improve performance.

Field of study: Engineering
J-PLUS: Two-dimensional analysis of the stellar population in NGC 5473 and NGC 5485

The spatial variations of stellar population properties within a galaxy are intimately related to their formation process. Therefore, spatially resolved studies of galaxies are essential to uncover their formation and assembly. The Javalambre Photometric Local Universe Survey (J-PLUS) is a dedicated multi-filter designed to observed ~8500 deg2 using twelve narrow-, intermediate- and broad-band filters in the optical range. In this study, we test the potential of the multi-filter observation carried out with J-PLUS to investigate the properties of spatially-resolved nearby galaxies. We present detailed 2D maps of stellar population properties (age, metallicity, extinction, and stellar mass surface density) for two early-type galaxies observed in both, J-PLUS and CALIFA surveys: NGC 5473 and NGC 5485. Radial structures are also compared and luminosity- and mass-weighted profiles are derived. We use MUFFIT to process the J-PLUS observations, and two different techniques (STARLIGHT and STECKMAP) to analyze IFU CALIFA data. We demonstrate that this novel technique delivers radial stellar population gradients in good agreement with the IFU technique CALIFA/STECKMAP although comparison of the absolute values reveals the existence of intrinsic systematic differences. Radial stellar population gradients differ when CALIFA/STARLIGHT methodology is used. Age and metallicity radial profiles derived from J-PLUS/MUFFIT are very similar when luminosity- or mass-weighted properties are used, suggesting that the contribution of a younger component is small. Comparison between the three methodologies reveals some discrepancies suggesting that the specific characteristics of each method causes important differences. We conclude that the ages, metallicities and extinction derived for individual galaxies not only depend on the chosen models but also depend on the method used.

Field of study: Physics
Horizontal Inequalities and Sons of the Soil Conflict in China

Why are large population movements conflict-prone in some regions while they remain peacefully integrated elsewhere? I argue that clashes between ethnically distinct indigenous populations and migrants – i.e. ‘Sons of the Soil (SoS) conflict’ – erupt when there are large socio-economic and political horizontal inequalities between ‘dominant migrants’ and locals. A comparative case study of two Chinese minority regions based on ethnographic fieldwork and population data provides a vivid illustration of the mechanisms linking migration to SoS conflict. With fewer HIs between migrants and locals, Inner Mongolia avoided many of the violent clashes that were commonplace in Qinghai, a province fraught with disparities.

Field of study: History, Sociology
Study on Anti-growth Property of In-situ Synthesized TiC_P/Fe and VC_P/Fe Composite

The anti-growth property of in-situ synthesized TiCP/Fe and VCP/Fe composite was studied.The results show that,by adding TiC and VC particulates,the anti-growth property of the two composites improves,which are obviously superior to that of HT250 and 45 steel.The anti-growth property of V CP / Fe composite is much better than Ti CP / Fe composite.

Field of study: Materials science
Econometric issues in modeling the costs of AIDS.

The goals of AIDS or HIV econometric modeling efforts are: (i) to evaluate or project the costs-of-illness to the individual and to society; and (ii) to examine the efficiency and cost-effectiveness of medical and social services provided to patients. Most of the standard theoretical and statistical approaches are not applicable because of the scarcity, incompleteness and non-representative nature of available data. This paper discusses specific methodological approaches concerning AIDS and HIV epidemiology, medical cost estimation techniques, evaluation of the cost-effectiveness of social support programs and valuation of human life. The epidemiologic projection approach--a simplified 'back calculation' method--suggests that the number of Americans infected with the AIDS virus in 1987-88 was likely to be between 500,000 and 800,000. This estimate is between 2 and 3 times lower than the U.S. Centers for Disease Control estimates. Methods for estimating both the direct and indirect costs of illness are described.

Field of study: Medicine, Political science
Encrypted Distributed Hash Tables

Distributed hash tables (DHT) are a fundamental building block in the design of distributed systems with applications ranging from content distribution networks to off-chain storage networks for blockchains and smart contracts. When DHTs are used to store sensitive information, system designers use end-to-end encryption in order to guarantee the confidentiality of their data. A prominent example is Ethereum’s off-chain network Swarm. In this work, we initiate the study of end-to-end encryption in DHTs and the many systems they support. We introduce the notion of an encrypted DHT and provide simulation-based security definitions that capture the security properties one would desire from such a system. Using our definitions, we then analyze the security of a standard approach to storing encrypted data in DHTs. Interestingly, we show that this “standard scheme” leaks information probabilistically, where the probability is a function of how well the underlying DHT load balances its data. We also show that, in order to be securely used with the standard scheme, a DHT needs to satisfy a form of equivocation with respect to its overlay. To show that these properties are indeed achievable in practice, we study the balancing properties of the Chord DHT—arguably the most influential DHT—and show that it is equivocable with respect to its overlay in the random oracle model. Finally, we consider the problem of encrypted DHTs in the context of transient networks, where nodes are allowed to leave and join.

Field of study: Computer science, Mathematics
The effects of enzyme concentration, temperature and incubation time on nitrogen content and degree of hydrolysis of protein precipitate from cockle (Anadara granosa) meat wash water

A study was carried out to determine the effect of enzyme concentration, temperature and incubation time of bromelain on nitrogen content (NC) and degree of hydrolysis (DH) of hydrolysate from cockle (Anadara granosa) meat wash water. Protein precipitation of cockle meat wash water was conducted at pH 4. The precipitate was then hydrolyzed using bromelain at concentrations of 0.5, 1.5 and 2.5 % (enzyme/substrate). The best enzyme concentration was subsequently used to study the effect of incubation temperature at 30, 45 and 60°C. The best temperature was then used to determine the effect of incubation time at 0, 24 and 48 hours. Increasing bromelain concentration from 0 to 2.5% produced an increase in NC and DH. Similarly, increasing the incubation time from 0 to 48 hours also increased the value of NC and DH. However, while the increasing of incubation temperature from 30 to 60°C produced an increase in NC, no significant difference was observed for DH.

Field of study: Agricultural and Food sciences
Construction of mutant strains of Klebsiella pneumoniae with ampG gene deletion

To construct mutant strains of Klebsiella pneumoniae with ampG gene deletion by homologous recombination and to evaluate the role of ampG gene in inducing the expression of AmpC enzyme. 
 
 
 
Polymerase chain reaction (PCR) was used to amplify the upstream and downstream fragments of ampG gene. The gene splicing by overlap extension PCR (SOE-PCR) technique was used to construct the fusion fragment, which was then ligated into the temperature sensitive suicide vector pKO3-km after enzyme digestion as pKO3-km-ΔampG. To achieve allelic exchange, the plasmid pKO3-km-ΔampG was introduced into Kp1 and Kp NTUH-K2044 strains by electroporation. The mutant strains of Klebsiella pneumoniae with ampG gene deletion were screened out. The plasmid pACYC184-ampCR was introduced into the Kp NTUH-K2044 wild-type strain and its mutant strain with ampG gene deletion to make them harbor the gene encoding AmpC enzyme. The disk diffusion method was used to evaluate the effects of ampG gene on the expression of AmpC enzyme in Klebsiella pneumoniae strains with cefoxitin as the inducer. 
 
 
 
The recombinant plasmid pKO3-km-ΔampG was constructed successfully. The mutant strains of Klebsiella pneumoniae with ampG gene deletion were constructed as verified by PCR and DNA sequencing. Compared with the Kp1 wild type strain, no AmpC enzyme was produced by the ampG gene knock-out Kp1 strain. The Kp NTUH-K2044 strain could produce AmpC enzyme, while the mutant strain of Kp NTUH-K2044 with ampG gene deletion could not after introduced the pACYC184-ampCR plasmid. 
 
 
 
The mutant strain of Klebsiella pneumoniae with ampG gene deletion was successfully constructed. The Klebsiella pneumonia strain without the ampG gene could not produce the AmpC enzyme. 
 
 
 
Klebsiella pneumoniae; ampG gene; Homologous recombination; Gene knock-out; AmpC enzyme

Field of study: Biology
Tanshinone IIA Stimulates Erythrocyte Phosphatidylserine Exposure

Tanshinone IIA, an antimicrobial, antioxidant, antianaphylactic, antifibrotic, vasodilating, antiatherosclerotic, organo-protective and antineoplastic component from the rhizome of Salvia miltiorrhiza, is known to trigger apoptosis of tumor cells. Tanshinone IIA is effective in part through mitochondrial depolarization and altered gene expression. Erythrocytes lack mitochondria and nuclei but may undergo eryptosis, an apoptosis-like suicidal cell death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the cell surface. Eryptosis is triggered by increase of cytosolic Ca2+ activity, ATP depletion and ceramide formation. The present study explored, whether tanshinone IIA elicits eryptosis. Cytosolic Ca2+-concentration was determined from Fluo3-fluorescence, cell volume from forward scatter, phosphatidylserine exposure from binding of fluorescent annexin V, hemolysis from hemoglobin concentration in the supernatant, ATP concentration utilizing luciferin–luciferase and ceramide formation utilizing fluorescent anticeramide antibodies. Clearance of circulating erythrocytes was estimated by CFSE-labeling. A 48 h exposure to tanshinone IIA (≥10 µM) significantly increased cytosolic Ca2+-concentration, decreased ATP concentration (25 µM), increased lactate concentration (25 µM), increased ceramide formation (25 µM), decreased forward scatter, increased annexin-V-binding and increased (albeit to a much smaller extent) hemolysis. The effect of 25 µM tanshinone IIA on annexin-V binding was partially reversed in the nominal absence of Ca2+. Labelled tanshinone IIA-treated erythrocytes were more rapidly cleared from the circulating blood in comparison to untreated erythrocytes. The present observations reveal a completely novel effect of tanshinone IIA, i.e. triggering of Ca2+ entry, ATP depletion and ceramide formation in erythrocytes, events eventually leading to eryptosis with cell shrinkage and cell membrane scrambling.

Field of study: Biology, Chemistry
Clinical and radiographic results of endoscopic injection for vesicoureteral reflux: defining measures of success.

Criteria for success following endoscopic vesicoureteral reflux (VUR) surgery vary greatly. We sought to define outcomes based on radiographic and long-term clinical follow up.



We reviewed the charts and interviewed parents of children who underwent endoscopic treatment for primary VUR (grades I-IV). All patients had a postoperative voiding cystourethrogram (VCUG) at mean of 3 months (1-21 months) and all cases of postoperative febrile urinary tract infection (FUTI) prompted repeat VCUG. Radiographic success was defined as no VUR on postoperative VCUG and clinical success as no FUTIs during follow up of 12-36 months. To demonstrate how criteria for success can affect outcomes, we calculated the success rates using different definitions.



In 2004-2008, 336 patients (296 female and 40 male, mean age 4 years) were treated with dextranomer/hyaluronic acid via the Double-HIT method. Initial radiographic success was 90% (302/336). Of these, 19 (6%) developed FUTIs, 12 (4%) of whom had recurrent VUR, and 5 (2%) went on to open surgery. Of the radiographic failures, 18% were observed with no further treatment. Success defined clinically was 94% (281/300), and as 'radiographic cure and no clinical evidence of FUTIs' it was 82% (275/336).



It is important to agree on a universal definition of success for VUR interventions to compare across studies and across therapies. Clinical success is more meaningful to the patient, and initial radiographic success could be followed by UTI necessitating further intervention. We question the need for routine postoperative VCUG.

Field of study: Medicine