Type Checking Research Articles

A Functional Programming Language with Versions

While modern software development heavily uses versioned packages, programming languages rarely support the concept of versions in their semantics, which makes software updates more bulky and unsafe. This paper proposes a programming language that intrinsically supports versions. The main goals are to design core language features to support multiple versions in one program and establish a proper notion of type safety with those features. The proposed core calculus, called Lambda VL, has versioned values, each containing different values under different versions. We show the construction of the type system as an extension of coeffect calculus by mapping versions to computational resources. The type system guarantees the existence of a valid combination of versions for a program. The calculus enables programming languages to use multiple versions of a package within a program. It will serve as a basis for designing advanced language features like module systems and semantic versioning.

Making legacy Fortran code type safe through automated program transformation

Fortran is still widely used in scientific computing, and a very large corpus of legacy as well as new code is written in FORTRAN 77. In general this code is not type safe, so that incorrect programs can compile without errors. In this paper, we present a formal approach to ensure type safety of legacy Fortran code through automated program transformation. The objective of this work is to reduce programming errors by guaranteeing type safety. We present the first rigorous analysis of the type safety of FORTRAN 77 and the novel program transformation and type checking algorithms required to convert FORTRAN 77 subroutines and functions into pure, side-effect free subroutines and functions in Fortran 90. We have implemented these algorithms in a source-to-source compiler which type checks and automatically transforms the legacy code. We show that the resulting code is type safe and that the pure, side-effect free and referentially transparent subroutines can readily be offloaded to accelerators.

P0021 - The safety and efficacy of botulinum toxin type A treatment in neurogenic detrusor overactivity and idiopathic overactive bladder: A systematic review and meta-analysis of prospective, randomized, double-blinded, placebo-controlled clinical trials

P0021 - The safety and efficacy of botulinum toxin type A treatment in neurogenic detrusor overactivity and idiopathic overactive bladder: A systematic review and meta-analysis of prospective, randomized, double-blinded, placebo-controlled clinical trials

676-P: Semaglutide Achieves Better Metabolic and Weight Control than Other GLP-1 RA in Real Life after 12 Months of Follow-up

Background and Aims: Weekly sc Semaglutide (WS) has demonstrated safety and efficacy in type 2 diabetes mellitus (T2D) in an extensive clinical development program. The main objective of the study was to assess the change in HbA1c and weight loss greater than 5% after 12 months of follow-up in real life. Materials and Methods: Retrospective observational study. Inclusion criteria:patients ≥ 18 years of age with T2D, eGFR ≥ 15 ml/min/1.73 m2 treated with WS. Main outcome variable: change in HbA1c (%) and weight ≥ 5% (kg). Secondary outcome variables: adverse events, withdrawal. Statistics: descriptive, student’s t, McNemar, multivariate logistic regression; SPSS vs. 19.0. Results: 247 patients, 55.4% men, age 62.8 ± 11.20 years, T2D evolution 10.4 ± 7.9 years; 14% smokers, 42.5% ex-smokers; 58% macroangiopathy, 54% microangiopathy; BMI 36.47 ± 6 Kg/m2; HbA1c 7.53 ± 1.4%; eGFR < 60 ml/min/1,73m2 46.5% and MAU > 30 mg/g 29.6%. In their baseline therapy, 55.9% used a GLP1 aR, (Liraglutide 66.7%, Dulaglutide 29.7%, ExenatideLAR 3.6%) and 44.8% insulin therapy. WS was suspended in 6.9% (44% digestive intolerance). 6.1% of patients on insulin had mild hypoglycemia. Overall, change in HbA1c -0.84 ± 1.1% (p <0.0001), change in weight -8 ± 16.6 kg (p <0.0001), weight change ≥ 5% 64.5%. The best compliance on weight change in people over 65 years of age with an OR 1.8 (95% CI: 1.02-3.17). Subpopulations analysis showed a change in HbA1c of -1.1 ± 1.2% (GLP1 aR naive) vs. -0.6 ± 1.9% (GLP1 aR prior-switch) (p 0.0001); weight change ≥ 5% -9.3 ± 6.4 Kg (GLP1aR naive) vs. -6.5 ± 6.7 Kg (GLP1 aR prior - switch) (p 0.0001). Significantly improved TAS (-7.5 ± 12.7 mmHg, p <0.0005), TAD (5.5 ± 9.4 p <0.0005), LDL -13.7 ± 30.11 mg/dl, p <0.0005, MALB 83.2 ± 432.4 mg/g, p <0.001. Conclusions: In real clinical practice, WS leads to an improvement in metabolic control and weight, both in patients T2D naïve to GLP1 aR (greater benefit), and in T2D patients previously treated with a different GLP1 aR, after one year. Disclosure M. Garcia de lucas: Advisory Panel; Spouse/Partner; Boehringer Ingelheim International GmbH, Novo Nordisk Inc., Speaker’s Bureau; Spouse/Partner; AstraZeneca, Lilly Diabetes, Sanofi. L. Pérez-belmonte: None. B. Aviles: None. A. Jimenez: None. J. Fernandez: None. F. Rivas ruiz: None.

A security type verifier for smart contracts

The widespread adoption of smart contracts demands strong security guarantees. Our work is motivated by the problem of statically checking potential information tampering in smart contracts. This paper presents a security type verification framework for smart contracts based on type systems. We introduce a formal calculus for reasoning smart contract operations and interactions and design a lightweight type system for checking secure information flow in Solidity (a popular high-level programming language for writing smart contracts). The soundness of our type system is proved w.r.t. non-interference. In addition, a type verifier based on our type system is proposed to assist users to automatically find an optimal secure type assignment for state variables, which makes contracts well-typed. We also prove that finding the optimal secure type assignment is theoretically a NP-complete problem. We develop a prototype implementation of the Solidity Type Verifier (STV) including the Solidity Type Checker (STC) based on the K-framework, and demonstrate its effectiveness on real-world smart contracts.

MO634SEMAGLUTIDE IN REAL LIFE PRACTICE DECREASES ALBUMINURIA IN HIGH RISK PROGRESSION CHRONIC KIDNEY DIABETIC PATIENTS

Abstract Background and Aims Semaglutide has shown safety and efficacy in type 2 diabetic patients (DM2) in extensive clinical studies including patients until eGFR>15ml/min/1.73m2. Our aims are to analyse the changes in metabolic and renal parameters in chronic diabetic patients after 12 months of treatment in real life practice with semaglutide. Method Retrospective observational study. Inclusion criteria: Patients over 18 years old with DM2 and eGFR(CKD-EPI)>15 ml/min/1.73m2. We selected cases with eGFR<60 ml/min/1,73m2 and/or albuminuria/Creatinineu (albu/creatu)>30 mg/g treated with semaglutide in real life practice for 12 months. Our main objectives were to assess the changes in HbA1c and weight. Secondary objetives to analyse evolution of albuminuria (albu/creatu), eGFR(CKD-EPI), blood pressure (BP), lipidic profile and adverse events. Statistics anlysis: we used descriptive, student's t, McNemar (paired data), method by steps forward; SPSS v 19.0. Results We included 122 patients, 62% males, mean age 51,43 ± 33 years, time of DM2 12.3 ± 3.4 years, body mass index (BMI) 35.8 ± 4.79, 25% had retinopathy, 93.4% hypercholesterolemia and 97% were hypertensive, 18% were active smokers. Mean Albu/Creatu: 349.49 ± 863.16 mg/g and mean eGFR (CKD-EPI): 50.32 ± 31.47 ml/min/1.73m2. Previous cardiovascular events: 36.5% myocardial infarction, 41% congestive hearth failure, 10% peripheric arteriopathy and 6% strokes. 42.6% were already on iSGT2 who were kept and 64.8% were switched from other GLP-1ar. After 12 months of treatment with semaglitude HbA1c reduced -0.74 ± 0.41% obtaining a mean objective <7% (from 7.57±1.36 to 6.83±0.85, p<0.0001). Patients decreased weight in -6.95 ± 6.0 Kg (from 98.48±16.6 to 91.53±16.42 p<00001) more than -5% of total body weight in 69% of cases. Albuminuria reduced in -162,21 mg/g ± 365,77 (from 349.49±863.16 to 187.287±897.39 p<0.0001, 53% reduction). eGFR(CKD-EPI) remained with a low increased of 2,2 ml/min/1.73m2. Systolic and Diastolic BP decreased -9.85 ± 13.34 mmHg (from 129.95±11,27 to 120.09±09 p < 0.0001) and -5.92 ± 7.43 mmHg (from 77.05±8.95 to 71.12±7.83 p< 0.0001) respectively. LDL-cholesterol and triglyceridemia decreased in -10.79 ± 28.21.09 mg/dl (p <0.0001) and -29,15 mg/dl ± 91,47 (p <0.0001) respectively. 5 % of patients on insulin had mild hipoglycemic episodes. Our patients needed 25% less units of rapid insulin (p<0.01). Semaglutide was stopped in 5% of cases (65% because digestive intolerance). Conclusion Chronic kidney diabetic patients with grade 3 albuminuria after 12 months of treatment in real life practice with semaglutide improved their glycemic control (mean final HbA1c <7%), with 25% less needs of rapid insulin. 69% of them decreased their total body weight in > 5%. We observed 53% reduction of albuminuria and better control of blood pressure.

Bidirectional Typing

Bidirectional typing combines two modes of typing: type checking, which checks that a program satisfies a known type, and type synthesis, which determines a type from the program. Using checking enables bidirectional typing to support features for which inference is undecidable; using synthesis enables bidirectional typing to avoid the large annotation burden of explicitly typed languages. In addition, bidirectional typing improves error locality. We highlight the design principles that underlie bidirectional type systems, survey the development of bidirectional typing from the prehistoric period before Pierce and Turner’s local type inference to the present day, and provide guidance for future investigations.

An Empirical Study of Type-Related Defects in Python Projects

In recent years, <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Python</monospace> has experienced an explosive growth in adoption, particularly among open source projects. While <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Python</monospace> 's dynamically-typed nature provides developers with powerful programming abstractions, that same dynamic type system allows for type-related defects to accumulate in code bases. To aid in the early detection of type-related defects, type annotations were introduced into the <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Python</monospace> ecosystem (i.e., PEP-484) and static type checkers like <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mypy</monospace> have appeared on the market. While applying a type checker like <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mypy</monospace> can in theory help to catch type-related defects before they impact users, little is known about the real impact of adopting a type checker to reveal defects in <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Python</monospace> projects. In this paper, we study the extent to which <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Python</monospace> projects benefit from such type checking features. For this purpose, we mine the issue tracking and version control repositories of 210 <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Python</monospace> projects on GitHub. Inspired by the work of Gao <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> on type-related defects in JavaScript, we add type annotations to test whether <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mypy</monospace> detects an error that would have helped developers to avoid real defects. We observe that 15 percent of the defects could have been prevented by <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mypy</monospace> . Moreover, we find that there is no significant difference between the experience level of developers committing type-related defects and the experience of developers committing defects that are not type-related. In addition, a manual analysis of the anti-patterns that most commonly lead to type-checking faults reveals that the redefinition of <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Python</monospace> references, dynamic attribute initialization and incorrectly handled Null objects are the most common causes of type-related faults. Since our study is conducted on fixed public defects that have gone through code reviews and multiple test cycles, these results represent a lower bound on the benefits of adopting a type checker. Therefore, we recommend incorporating a static type checker like <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mypy</monospace> into the development workflow, as not only will it prevent type-related defects but also mitigate certain anti-patterns during development.

Long-term safety and outcomes in hereditary tyrosinaemia type 1 with nitisinone treatment: a 15-year non-interventional, multicentre study

Since the EU approval of nitisinone in 2005, prognosis for patients with hereditary tyrosinaemia type 1 has changed dramatically, with patients living with the disease now reaching adulthood for the first time in history. This study aimed to assess the long-term safety and outcomes of nitisinone treatment in patients with hereditary tyrosinaemia type 1. We did a non-interventional, non-comparative, multicentre study in 77 sites across 17 countries in Europe and collected retrospective and prospective longitudinal data in patients with hereditary tyrosinaemia type 1 who were treated with oral nitisinone during the study period (Feb 21, 2005, to Sept 30, 2019). There were no specific exclusion criteria. Patients were followed-up with an investigator at least annually for as long as they were treated, or until the end of the study. The primary endpoints, occurrence of adverse events related to hepatic, renal, ophthalmic, haematological, or cognitive or developmental function, were assessed in the complete set (all patients already receiving treatment at the index date [Feb 21, 2005] or starting treatment thereafter) and the index set (the subset of patients who had their first dose on the index date or later only). 315 patients were enrolled during the study period (complete set). Additionally, data from 24 patients who had liver transplantation or died during the post-marketing surveillance programme were retrieved (extended analysis set; 339 patients). Median treatment duration was 11·2 years (range 0·7-28·4); cumulative nitisinone exposure was 3172·7 patient-years. Patients who were diagnosed by neonatal screening started nitisinone treatment at median age 0·8 months versus 8·5 months in those who presented clinically. Incidences of hepatic, renal, ophthalmic, haematological, or cognitive or developmental adverse events were low. Occurrence of liver transplantation or death was more frequent the later that treatment was initiated (none of 70 patients who started treatment at age <28 days vs 35 [13%] of 268 patients who started treatment at age ≥28 days). 279 (89%) of 315 patients were assessed as having either very good or good nitisinone treatment compliance. Treatment and diet compliance declined as patients aged. Suboptimal plasma phenylalanine and tyrosine levels were observed. The majority of patients were reported to have good overall clinical condition throughout treatment; 176 (87%) of 203 during the entire study, 98% following 1 year of treatment. Long-term nitisinone treatment was well tolerated and no new safety signals were revealed. Life-limiting hepatic disease appears to have been prevented by early treatment start. Neonatal screening was the most effective way of ensuring early treatment. Standardised monitoring of blood tyrosine, phenylalanine, and nitisinone levels has potential to guide individualised therapy. Swedish Orphan Biovitrum (Sobi).

Safety and efficacy of Botulinum toxin type A preparations in cerebral palsy - an evidence-based review.

The introduction of botulinum toxin more than 25 years ago for the management of paediatric lower and upper limb hypertonia has been a major advance. BoNT-A as a part of multimodal treatment supports motor development and improves function disturbed by spasticity or hypertonia. The aim of this paper was to compare the efficacy and safety of three major BoNT-A preparations present on the market: abo-, inco-, and onaobotulinumtoxinA in the treatment of children with cerebral palsy. Based on an analysis of the available literature, all three preparations have been established to reduce hypertonia in the upper and lower extremities, with some conflicting evidence regarding function. There were no differences in treatment safety, with a low incidence of adverse events which were mostly temporary and mild. Any form of universal conversion ratio between all preparations is not recommended.

A Formal Framework of Software Product Line Analyses

A number of product-line analysis approaches lift analyses such as type checking, model checking, and theorem proving from the level of single programs to the level of product lines. These approaches share concepts and mechanisms that suggest an unexplored potential for reuse of key analysis steps and properties, implementation, and verification efforts. Despite the availability of taxonomies synthesizing such approaches, there still remains the underlying problem of not being able to describe product-line analyses and their properties precisely and uniformly. We propose a formal framework that models product-line analyses in a compositional manner, providing an overall understanding of the space of family-based, feature-based, and product-based analysis strategies. It defines precisely how the different types of product-line analyses compose and inter-relate. To ensure soundness, we formalize the framework, providing mechanized specification and proofs of key concepts and properties of the individual analyses. The formalization provides unambiguous definitions of domain terminology and assumptions as well as solid evidence of key properties based on rigorous formal proofs. To qualitatively assess the generality of the framework, we discuss to what extent it describes five representative product-line analyses targeting the following properties: safety, performance, dataflow facts, security, and functional program properties.

A dependently typed calculus with polymorphic subtyping

• A dependently-typed language that features implicit polymorphism, general recursion and explicit type-level computation. • Higher ranked subtype reasoning about the more-general-than relation between polymorphic types. • Fully mechanized proof of the type soundness and transitivity. A polymorphic subtyping relation, which relates more general types to more specific ones, is at the core of many modern functional languages. As those languages start moving towards dependently typed programming a natural question is how can polymorphic subtyping be adapted to such settings. This paper presents the dependent implicitly polymorphic calculus ( λ I ∀ ): a simple dependently typed calculus with polymorphic subtyping. The subtyping relation in λ I ∀ generalizes the well-known polymorphic subtyping relation by Odersky and Läufer (1996). Because λ I ∀ is dependently typed, integrating subtyping in the calculus is non-trivial. To overcome many of the issues arising from integrating subtyping with dependent types, the calculus employs unified subtyping , which is a technique that unifies typing and subtyping into a single relation. Moreover, λ I ∀ employs explicit casts instead of a conversion rule, allowing unrestricted recursion to be naturally supported. We prove various non-trivial results, including type soundness and transitivity of unified subtyping. λ I ∀ and all corresponding proofs are mechanized in the Coq theorem prover.

Design and implementation of an efficient program interpreter for industrial robot

Robot program interpreter is an important tool for robot to realize real-time control and fast feedback. In order to simplify the process of robot programming and improve the interpretation efficiency of robot program, an easy-to-use and efficient industrial robot program interpreter is designed and implemented in this paper. The interpreter divides the robot program into two parts: variable definition and instruction call. The process of interpretation includes lexical analysis, syntactic analysis, semantic analysis and instruction interpretation modules. Using flex and bison tools to assist in the generation of lexical and syntactic analysis programs, this paper proposes child-sibling notation (CSN) to construct a syntax tree. In semantic analysis, the red-black tree structure of the map container is used to create a symbol table and record variable information. By the way of presetting type checking codes, errors in the program can be reported and handled. Finally, the interpreter traverses the syntax tree with depth-first algorithm, and calls the corresponding control function while interpreting the instruction sentence to execute the motion of robot. The experimental results show that the designed interpreter has high efficiency and stability in interpreting the robot program and meets the operational requirements of industrial robots.

A Lightweight Formalism for Reference Lifetimes and Borrowing in Rust

Rust is a relatively new programming language that has gained significant traction since its v1.0 release in 2015. Rust aims to be a systems language that competes with C/C++. A claimed advantage of Rust is a strong focus on memory safety without garbage collection. This is primarily achieved through two concepts, namely, reference lifetimes and borrowing . Both of these are well-known ideas stemming from the literature on region-based memory management and linearity / uniqueness . Rust brings both of these ideas together to form a coherent programming model. Furthermore, Rust has a strong focus on stack-allocated data and, like C/C++ but unlike Java, permits references to local variables. Type checking in Rust can be viewed as a two-phase process: First, a traditional type checker operates in a flow-insensitive fashion; second, a borrow checker enforces an ownership invariant using a flow-sensitive analysis. In this article, we present a lightweight formalism that captures these two phases using a flow-sensitive type system that enforces “ type and borrow safety .” In particular, programs that are type and borrow safe will not attempt to dereference dangling pointers. Our calculus core captures many aspects of Rust, including copy- and move-semantics, mutable borrowing, reborrowing, partial moves, and lifetimes. In particular, it remains sufficiently lightweight to be easily digested and understood and, we argue, still captures the salient aspects of reference lifetimes and borrowing. Furthermore, extensions to the core can easily add more complex features (e.g., control-flow, tuples, method invocation). We provide a soundness proof to verify our key claims of the calculus. We also provide a reference implementation in Java with which we have model checked our calculus using over 500B input programs. We have also fuzz tested the Rust compiler using our calculus against 2B programs and, to date, found one confirmed compiler bug and several other possible issues.

EDUKASI KADER PKK MENJADI PERINTIS KAMPUNG DONOR DARAH MANDIRI SAAT PANDEMI COVID-19

The Corona Virus-19 (Covid-19) outbreak in Indonesia has caused many problems including blood supply which will be significantly affected by decreasing the amount of blood donated. The Blood Transfusion Unit (UTD) must be ready to move quickly in response to the changes that occur, where an adequate blood supply is most likely to be affected. Purpose: to encourage the community of Partners to become voluntary blood donors so that they can help residents in keeping the availability of blood safe during the Covid-19 Pandemic. Methods: cadres from members of Family Welfare Empowerment (PKK) Sungapan, Sriharjo, Imogiri, Bantul, were trained to carry out initial donor selection examinations including blood pressure checks, hemoglobin level checks, blood type checks and doing it independently so that it can increase the role of voluntary blood donors. This outreach activity is to educate the community to form a cadre of PKK mothers to be trained in conducting initial donor selection checks so that data can be used as a means of obtaining voluntary donors in Mitra areas and creating independent blood donor villages. Conclusion: PKK cadres have been able to provide counseling to residents and are able to check blood pressure, hemoglobin levels and blood type keywords: cadre, blood donation village

Experience of Botulinum Toxin A Injections for Chronic Migraine Headaches in a Pediatric Chronic Pain Clinic.

Prevalence of chronic migraine in children can reach 7.7%, causing decreased school performance, difficulty with extracurricular activities (including sports, theater, or music), and changes in sleep and mood. Many studies confirm that botulinum toxin type A injections effectively alleviate chronic migraines in adults; however, the literature regarding children is sparse. This study aims to analyze the safety and effectiveness of botulinum type A injections in a group of pediatric patients diagnosed with chronic migraines in a pediatric pain clinic. In this retrospective (2013-2018) study, the effects of botulinum toxin type A injections were analyzed using data from 65 pediatric patients diagnosed with chronic migraines. The study group ranged from 11 to 18 years of age. A pediatric pain management physician administered the botulinum using the Phase 3 Research Evaluating Migraine Prophylaxis Therapy program protocol and followed the pain pattern. Dosages, tolerance, and side effects were measured. In this study, 74% of the patients tried more than 6 medications before the injections. There was a decrease in the visual analog scale score of 5.2 ± 2.2 points upon 6-week follow-up. The mean amount of medication used was 173.2 ± 35 units, and patients received an average of 2.8 ± 1.1 units/kg. Adverse events include one patient who developed dizziness and another who had low-grade fevers with enlarged cervical lymph nodes; both resolved within few minutes. This study supports the use of botulinum type A for chronic migraines in pediatric patients. Multicentered, randomized studies with larger population are needed to evaluate the long-term safety and efficacy of this therapy.

Comparison of efficacy and safety of daily oral L-arginine and PDE5Is alone or combination in treating erectile dysfunction: A systematic review and meta-analysis of randomised controlled trials.

The meta-analysis was performed to assess the efficacy and safety of daily oral L-arginine and phosphodiesterase type 5 inhibitors (PDE5Is) alone or combination in treating patients with erectile dysfunction (ED). We performed a search of randomised controlled trials in the following databases: PubMed, EMBASE and Cochrane Library databases. Four articles including 373 patients were studied. Erectile functions were significantly improved in three therapy groups compared with baseline. Patients who received the combination of L-arginine and PDE5Is showed significant improvement compared to those treated with L-arginine and PDE5Is alone, as assessed by sexual function index (p<0.00001 and p=0.005, respectively) and total testosterone (p<0.00001 and p=0.0007, respectively). Furthermore, patients who treated with PDE5Is alone exhibited the better efficacy than those treated with L-arginine alone in respects of sexual function index (p<0.00001) and total testosterone (p=0.0001). However, the combination of L-arginine and PDE5Is had no obvious difference relative to PDE5Is alone in terms of various adverse events (AEs). Conclusively, compared with monotherapy, the combination of L-arginine and PDE5Is showed a greater improvement of sexual function and total testosterone, and did not significantly increase the AEs. Besides, PDE5Is alone revealed a better effect than those treated with L-arginine alone for patients with ED.

Hemifacial spasm through the last three decades: From etiology to efficacy and safety of long-term botulinum toxin treatment

BackgroundHemifacial spasm (HFS) is an uncommon movement disorder characterized by involuntary contractions of muscles innervated by the facial nerve. The aim of this study is to analyze the etiology of HFS as well as the efficacy and safety of long-term botulinum toxin type A (BTX-A) treatment. MethodsRetrospective study including 125 patients with HFS treated with BTX-A from 1993 to 2019. Demographic and etiological variables as well as doses, number of sessions of BTX-A, infiltrated muscles, therapeutic response according to Patient Global Impression of Change Scale (PGIC-S), side effects and adjuvant treatments were analyzed. In addition, these variables were compared according to the etiology (idiopathic versus secondary). Results92 patients (73.6%) were women and the mean age at diagnosis was 58.63 years (SD 15.4). The etiology was idiopathic in 79 patients (63.2%), 17.6% were secondary to Bell’s palsy, 14.4% to vascular compression and 2.4% to tumors. A higher total dose per session was observed in the secondary group. PGIC-S showed a good response in 96% of cases. 16 patients (12.8%) required pharmacological concomitant treatment. 59 patients (47.2%) developed side effects. Transient eyelid ptosis and facial weakness were the most common. ConclusionsThe structural origin of a significant number of cases of HFS makes essential to complete an etiological diagnosis in all patients. In addition, the existence of a secondary cause could be associated with greater doses of BTX-A to achieve a good response. Regardless the etiology, long-term treatment with BTX-A in HFS is safe and effective.

An Empirical Study on Type Annotations

Type annotations connect variables to domain-specific types. They enable the power of type checking and can detect faults early. In practice, type annotations have a reputation of being burdensome to developers. We lack, however, an empirical understanding of how and why they are burdensome. Hence, we seek to measure the baseline accuracy and speed for developers making type annotations to previously unseen code. We also study the impact of one or more type suggestions. We conduct an empirical study of 97 developers using 20 randomly selected code artifacts from the robotics domain containing physical unit types. We find that subjects select the correct physical type with just 51% accuracy, and a single correct annotation takes about 2 minutes on average. Showing subjects a single suggestion has a strong and significant impact on accuracy both when correct and incorrect, while showing three suggestions retains the significant benefits without the negative effects. We also find that suggestions do not come with a time penalty. We require subjects to explain their annotation choices, and we qualitatively analyze their explanations. We find that identifier names and reasoning about code operations are the primary clues for selecting a type. We also examine two state-of-the-art automated type annotation systems and find opportunities for their improvement.

Breaking Type Safety in Go: An Empirical Study on the Usage of the unsafe Package

A decade after its first release, the Go programming language has become a major programming language in the development landscape. While praised for its clean syntax and C-like performance, Go also contains a strong static type-system that prevents arbitrary type casting and arbitrary memory access, making the language type-safe by design. However, to give developers the possibility of implementing low-level code, Go ships with a special package called unsafe that offers developers a way around the type-safety of Go programs. The package gives greater flexibility to developers but comes at a higher risk of runtime errors, chances of non-portability, and the loss of compatibility guarantees for future versions of Go. In this paper, we present the first large-scale study on the usage of the unsafe package in 2,438 popular Go projects. Our investigation shows that unsafe is used in 24% of Go projects, motivated primarily by communicating with operating systems and C code, but is also commonly used as a source of performance optimization. Developers are willing to use unsafe to break language specifications (e.g., string immutability) for better performance and 6% of analyzed projects that use unsafe perform risky pointer conversions that can lead to program crashes and unexpected behavior. Furthermore, we report a series of real issues faced by projects that use unsafe, from crashing errors and non-deterministic behavior to having their deployment restricted from certain popular environments. Our findings can be used to understand how and why developers break type-safety in Go, and help motivate further tools and language development that could make the usage of unsafe in Go even safer.