Elizabeth L Corbett
Dados Biográficos
| ID | 217680 |
|---|---|
| NOME | Elizabeth L Corbett |
| PRENOMES | Elizabeth L |
| SOBRENOME | Corbett |
| ASSINATURA | CORBETT E L |
| AFILIAÇÕES | University of Liverpool |
| ORCID | 0000-0002-3552-3181 |
| VERIFICADO | Sim |
| TOTAL DE OBRAS | 46 |
| TOTAL DE CITAÇÕES | 2 |
| TOTAL COMO AUTOR | 46 |
| TOTAL COMO EDITOR | 0 |
| PRIMEIRO ANO DE PUBLICAÇÃO | 2003 |
| ANO MAIS RECENTE DE PUBLICAÇÃO | 2026 |
| ÍNDICE H | 1 |
Perceived gender equitable norms and previous tuberculosis testing in Malawi
Substantial evidence demonstrates that men have a higher prevalence of tuberculosis (TB) and decreased use of TB services compared to women. Gender roles and norms contribute to these disparities by influencing social and structural determinants, as well as individual behaviours. In this analysis, we investigated attitudes towards gender equitable norms and TB testing behaviours amongst Malawian men and women participating in a prevalence survey …
Acceptability of Covid-19 self-testing among social and clinical vulnerable populations using a decentralized testing model in Abuja, Nigeria; A mixed methods analysis of an implementation study
Diagnostic testing is critical during infectious disease outbreaks, enabling timely patient management and isolation to reduce transmission and mortality. During the COVID-19 outbreak in Nigeria, testing rates remained low due to limited access to centralized RT-PCR sites. To expand access, the National COVID-19 Testing Strategy (January 2021) introduced decentralized self-testing models targeting vulnerable populations. This study assessed the u…
Distribution and transmission of M. tuberculosis in a high-HIV prevalence city in Malawi
Delays in identifying and treating individuals with infectious tuberculosis (TB) contribute to poor health outcomes and allow ongoing community transmission of M. tuberculosis ( Mtb ). Current recommendations for screening for tuberculosis specify community characteristics (e.g., areas with high local tuberculosis prevalence) that can be used to target screening within the general population. However, areas of higher tuberculosis burden are not n…
Do community-level factors play a role in HIV self-testing uptake, linkage to services and HIV-related outcomes? A mixed methods study of community-led HIV self-testing in rural Zimbabwe
Community-led interventions, where communities plan and lead implementation, are increasingly being adopted within public health programmes. We explore factors associated with successful community-led distribution of HIV self-test (HIVST) kits to guide future service delivery. Twenty rural communities were supported to distribute HIVST kits for 1-month between January and September 2019. Social science researchers observed communities during plan…
Who has never tested for HIV following a community-based distribution of HIV self-test kits? Establishing associated predictors in rural Zimbabwe
In 2023, Zimbabwe attained the 95-95-95 UNAIDS targets. However, some sub-populations are substantially less likely to have tested for HIV. Knowledge of characteristics of these groups is crucial in designing interventions that address their needs. We estimated the prevalence and predictors of “never-having tested for HIV” status following community-based distribution of HIV self-test kits in rural Zimbabwe. We analysed data from a household surv…
Provider costs of professional Covid-19 rapid antigen testing in low-income settings
World Health Organization recommends antigen rapid diagnostic tests (RDT) as point of care tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in suspected outbreaks when polymerase-chain-reaction testing is not accessible; to trace the extent of outbreaks; and in areas with widespread community transmission. Annual economic costs were estimated for professional SARS-CoV-2 testing as part of several COVID-19 testing use cases i…
Covid-19 diagnosis within five days of symptoms onset among healthcare workers in Malawi; Non-randomized control trial of self-testing using Ag-RDTs
Efficient and sustainable models of Corona Virus Disease of 2019 (COVID‐19) screening among healthcare workers (HCWs) such as self-testing are essential for averting transmission within and outside health care facilities. We compared the number of confirmed early COVID‐19 positive diagnoses (defined as COVID‐19 cases diagnosed within five days of symptoms onset) among HCW in self-testing arm using Antigen Rapid Diagnostic Test kits (Ag-RDT) and s…
Understanding the acceptability of Covid-19 antigen rapid diagnostic tests
Accessible and timely diagnostic testing was essential during the COVID-19 pandemic to control the virus’s spread and mitigate severe outcomes. However, real-time polymerase chain reaction tests, although sensitive incur high costs and prolonged turnaround times, and face implementation challenges in many resource-constrained settings. Antigen rapid diagnostic tests (Ag-RDT), which can be administered either by providers or as self-tests, are acc…
Community-led strategies for communicable disease prevention and management in low- and middle- income countries
Control of infectious diseases is a global health priority and a target of the 2015-2030 Sustainable Development Goals (SDGs). Community participation is fundamental to advancing primary health care and meeting SDGs. We conducted a mixed-methods systematic literature review of quantitative and qualitative evidence to understand the health, social, and economic impact of community-led strategies for communicable disease prevention and management i…
Impact of active case-finding for tuberculosis on case-notifications in Blantyre, Malawi
Active case-finding (ACF) for tuberculosis can help find the “missing millions” with undiagnosed tuberculosis. In a cluster-randomised trial, we investigated impact of ACF on case-notifications in Blantyre, Malawi, where ACF has been intensively implemented following 2014 estimates of ~1,000 per 100,000 adults with undiagnosed TB. Following a pre-intervention prevalence survey (May 2019 to March 2020), constrained randomisation allocated neighbou…
Interventions to reduce deaths in people living with HIV admitted to hospital in low- and middle-income countries
People living with HIV (PLHIV) admitted to hospital have a high risk of death. We systematically appraised evidence for interventions to reduce mortality among hospitalised PLHIV in low- and middle-income countries (LMICs). Using a broad search strategy with terms for HIV, hospitals, and clinical trials, we searched for reports published between 1 Jan 2003 and 23 August 2021. Studies of interventions among adult HIV positive inpatients in LMICs w…
Prevalence of bacteriologically-confirmed pulmonary tuberculosis in urban Blantyre, Malawi 2019–20
Recent evidence shows rapidly changing tuberculosis (TB) epidemiology in Southern and Eastern Africa, with need for subdistrict prevalence estimates to guide targeted interventions. We conducted a pulmonary TB prevalence survey to estimate current TB burden in Blantyre city, Malawi. From May 2019 to March 2020, 115 households in middle/high-density residential Blantyre, were randomly-selected from each of 72 clusters. Consenting eligible particip…
Understanding mechanisms of impact from community-led delivery of HIV self-testing
Community HIV strategies are important for early diagnosis and treatment, with new self-care technologies expanding the types of services that can be led by communities. We evaluated mechanisms underlying the impact of community-led delivery of HIV self-testing (HIVST) using mediation analysis. We conducted a cluster-randomised trial allocating 30 group village heads and their catchment areas to the community-led HIVST intervention in addition to…
User perspectives and preferences on a novel TB LAM diagnostic (Fujifilm Silvamp TB LAM)–a qualitative study in Malawi and Zambia
Widely available tuberculosis (TB) diagnostics use sputum samples. However, many patients, particularly children and patients living with HIV (PLHIV), struggle to provide sputum. Urine diagnostics are a promising approach to circumvent this challenge while delivering reliable and timely diagnosis. This qualitative study in two high TB/HIV burden countries assesses values and preferences of end-users, along with potential barriers for the implemen…
Know your tuberculosis epidemic–Is it time to add Mycobacterium tuberculosis immunoreactivity back into global surveillance
Tuberculosis (TB) still causes 1.5 million deaths globally each year. Over recent decades, slow and uneven declines in TB incidence have resulted in a falling prevalence of TB disease, which increasingly concentrates in vulnerable populations. Falling prevalence, while welcome, poses new challenges for TB surveillance. Cross-sectional disease surveys require very large sample sizes to accurately estimate disease burden, and even more participants…
Population benefits of addressing programmatic and social determinants of gender disparities in tuberculosis in Viet Nam
High prevalence of infectious tuberculosis among men suggests potential population-wide benefits from addressing programmatic and social determinants of gender disparities. Utilising a sex-stratified compartmental transmission model calibrated to tuberculosis burden estimates for Viet Nam, we modelled interventions to increase active case finding, to reduce tobacco smoking, and to reduce alcohol consumption by 2025 in line with national and globa…
Does community-based distribution of HIV self-tests increase uptake of HIV testing? Results of pair-matched cluster randomised trial in Zambia
OBJECTIVES: Ending HIV by 2030 is a global priority. Achieving this requires alternative HIV testing strategies, such as HIV self-testing (HIVST) to reach all individuals with HIV testing services (HTS). We present the results of a trial evaluating the impact of community-based distribution of HIVST in community and facility settings on the uptake of HTS in rural and urban Zambia. DESIGN: Pair-matched cluster randomised trial. METHODS: In catchme…
Innovative demand creation strategies to increase voluntary medical male circumcision uptake
INTRODUCTION: Reaching men aged 20-35 years, the group at greatest risk of HIV, with voluntary medical male circumcision (VMMC) remains a challenge. We assessed the impact of two VMMC demand creation approaches targeting this age group in a randomised controlled trial (RCT). METHODS: We conducted a 2×2 factorial RCT comparing arms with and without two interventions: (1) standard demand creation augmented by human-centred design (HCD)-informed app…
ART initiations following community-based distribution of HIV self-tests
INTRODUCTION: Measuring linkage after community-based testing, particularly HIV self-testing (HIVST), is challenging. Here, we use data from studies of community-based HIVST distribution, conducted within the STAR Initiative, to assess initiation of antiretroviral therapy (ART) and factors driving differences in linkage rates. METHODS: Five STAR studies evaluated HIVST implementation in Malawi, Zambia and Zimbabwe. New ART initiations during the …
Community-based HIV self-testing
BACKGROUND: HIV self-testing (HIVST) requires linkage to post-test services to maximise its benefits. We evaluated effect of supply-side incentivisation on linkage following community-based HIVST and evaluated time-trends in facility-based antiretroviral therapy (ART) initiations. METHODS: From August 2016 to August 2017 community-based distributors (CBDs) in 38 rural Zimbabwean communities distributed HIVST door-to-door in 19-25 day campaigns. C…
Effect of peer-distributed HIV self-test kits on demand for biomedical HIV prevention in rural KwaZulu-Natal, South Africa
Study objective We investigated two peer distribution models of HIV self-testing (HIVST) in HIV prevention demand creation compared with trained young community members (peer navigators). Methods We used restricted randomisation to allocate 24 peer navigator pairs (clusters) in KwaZulu-Natal 1:1:1: (1) standard of care ( SOC): peer navigators distributed clinic referrals, pre-exposure prophylaxis (PrEP) and antiretroviral therapy (ART) informatio…
Effect of door-to-door distribution of HIV self-testing kits on HIV testing and antiretroviral therapy initiation
INTRODUCTION: Reaching high coverage of HIV testing remains essential for HIV diagnosis, treatment and prevention. We evaluated the effectiveness and safety of door-to-door distribution of HIV self-testing (HIVST) kits in rural Malawi. METHODS: This cluster randomised trial, conducted between September 2016 and January 2018, used restricted 1:1 randomisation to allocate 22 health facilities and their defined areas to door-to-door HIVST alongside …
Pragmatic economic evaluation of community-led delivery of HIV self-testing in Malawi
INTRODUCTION: Community-based strategies can extend coverage of HIV testing and diagnose HIV at earlier stages of infection but can be costly to implement. We evaluated the costs and effects of community-led delivery of HIV self-testing (HIVST) in Mangochi District, Malawi. METHODS: This economic evaluation was based within a pragmatic cluster-randomised trial of 30 group village heads and their catchment areas comparing the community-led HIVST i…
Comparison of community-led distribution of HIV self-tests kits with distribution by paid distributors
BACKGROUND: We compared community-led versus an established community-based HIV self-testing (HIVST) model in rural Zimbabwe using a cluster-randomised trial. METHODS: Forty village groups were randomised 1:1 using restricted randomisation to community-led HIVST, where communities planned and implemented HIVST distribution for 4 weeks, or paid distribution (PD), where distributors were paid US$50 to distribute kits door-to-door over 4 weeks. Indi…
Costs of integrating HIV self-testing in public health facilities in Malawi, South Africa, Zambia and Zimbabwe
INTRODUCTION: As countries approach the UNAIDS 95-95-95 targets, there is a need for innovative and cost-saving HIV testing approaches that can increase testing coverage in hard-to-reach populations. The HIV Self-Testing Africa-Initiative distributed HIV self-test (HIVST) kits using unincentivised HIV testing counsellors across 31 public facilities in Malawi, South Africa, Zambia and Zimbabwe. HIVST was distributed either through secondary (partn…
Whose failure counts?' A critical reflection on definitions of failure for community health volunteers providing HIV self-testing in a community-based HIV/TB intervention study in urban Malawi
The category of community health worker applied within the context of health intervention trials has been promoted as a cost-effective approach to meeting study objectives across large populations, relying on the promotion of the concept of 'community belonging' to encourage altruistic volunteerism from community members to promote health. This community-based category of individuals is recruited to facilitate externally driven priorities defined…
Perception of Risk of Vertically Acquired HIV Infection and Acceptability of Provider-Initiated Testing and Counseling Among Adolescents in Zimbabwe
Objectives. We investigated attitudes toward provider-initiated HIV testing and counseling (PITC) in the suburbs of Harare, Zimbabwe, where late presentation after mother-to-child HIV transmission (MTCT) is a major cause of adolescent mortality. Methods. Adolescents (10–18 years) attending 2 primary clinics were offered PITC. Participants completed a questionnaire investigating acceptability of PITC, and in-depth interviews with 41 adolescents an…
The Growing Burden of Tuberculosis
BACKGROUND: The increasing global burden of tuberculosis (TB) is linked to human immunodeficiency virus (HIV) infection. METHODS: We reviewed data from notifications of TB cases, cohort treatment outcomes, surveys of Mycobacterium tuberculosis infection, and HIV prevalence in patients with TB and other subgroups. Information was collated from published literature and databases held by the World Health Organization (WHO), the Joint United Nations …
A Randomized, Controlled Trial of Financial Incentives for Smoking Cessation
BACKGROUND: Smoking is the leading preventable cause of premature death in the United States. Previous studies of financial incentives for smoking cessation in work settings have not shown that such incentives have significant effects on cessation rates, but these studies have had limited power, and the incentives used may have been insufficient. METHODS: We randomly assigned 878 employees of a multinational company based in the United States to …
The Uptake and Accuracy of Oral Kits for HIV Self-Testing in High HIV Prevalence Setting
BACKGROUND: Although HIV testing and counseling (HTC) uptake has increased dramatically in Africa, facility-based services are unlikely to ever meet ongoing need to the full. A major constraint in scaling up community and home-based HTC services is the unacceptability of receiving HTC from a provider known personally to prospective clients. We investigated the potential of supervised oral HIV self-testing from this perspective. METHODS AND FINDIN…
Perception of Risk of Vertically Acquired HIV Infection and Acceptability of Provider-Initiated Testing and Counseling Among Adolescents in Zimbabwe
Objectives. We investigated attitudes toward provider-initiated HIV testing and counseling (PITC) in the suburbs of Harare, Zimbabwe, where late presentation after mother-to-child HIV transmission (MTCT) is a major cause of adolescent mortality. Methods. Adolescents (10–18 years) attending 2 primary clinics were offered PITC. Participants completed a questionnaire investigating acceptability of PITC, and in-depth interviews with 41 adolescents an…
Burden of HIV among primary school children and feasibility of primary school-linked HIV testing in Harare, Zimbabwe
Population-based surveys in Southern Africa suggest a substantial burden of undiagnosed HIV-infected long-term survivors of mother-to-child transmission. We conducted an HIV prevalence survey of primary school pupils in Harare, Zimbabwe, and evaluated school-linked HIV counselling and testing (HCT) for pupils, their families and schoolteachers. Population-weighted cluster sampling was used to select six primary schools. Randomly selected class-gr…
Newborn survival
Health Policy & Planning volume 27 supplement 3: A decade of change for newborn survival, policy and programmes (2000–2010), July 2012 pp. iii6–iii28 doi:10.1093/heapol/czs053 This article contained errors on p. 8, para 1 and in Table 3. The health density figures should refer to the number of midwives, nurses and physicians per 100 000, not per 10 000. The sentence on p. 8 should read: The density of midwives and nurses is over 30-fold higher in…
Control, struggle, and emergent masculinities
Facilitating men to seek care early is an urgent public health imperative, given the contexts of high HIV/AIDS prevalence but increasingly available treatment, and the role of care-seeking delay in TB transmission. Men's struggles trying to achieve ideal images seem to influence their engagement with their health. Ambiguous views regarding some key masculinity representations and the embrace of less harmful masculinities raise questions about som…
Factors Shaping Initial Decision-Making to Self-test Amongst Cohabiting Couples in Urban Blantyre, Malawi
In sub-Saharan Africa, most new HIV infections occur in stable relationships, making couples testing an important intervention for HIV prevention. We explored factors shaping the decision-making of cohabiting couples who opted to self-test in Blantyre, Malawi. Thirty-four self-tested participants (17 couples) were interviewed. Motivators for HIV self-testing (HIVST) emerged at three main levels. Individual motivations included perceived benefits …
Uptake, Accuracy, Safety, and Linkage into Care over Two Years of Promoting Annual Self-Testing for HIV in Blantyre, Malawi
BACKGROUND: Home-based HIV testing and counselling (HTC) achieves high uptake, but is difficult and expensive to implement and sustain. We investigated a novel alternative based on HIV self-testing (HIVST). The aim was to evaluate the uptake of testing, accuracy, linkage into care, and health outcomes when highly convenient and flexible but supported access to HIVST kits was provided to a well-defined and closely monitored population. METHODS AND…
‘For a mere cough, men must just chew Conjex , gain strength, and continue working’
BACKGROUND: Delay by men in seeking healthcare results in their higher mortality while on HIV or tuberculosis (TB) treatment and contributes to ongoing community-level disease transmission before going on treatment. OBJECTIVE: To understand masculinity's role in delay in healthcare seeking for men, with a focus on TB-suggestive symptoms. DESIGN: Data were collected between March 2011 and March 2012 in low-income suburbs in urban Blantyre using fo…
Whose failure counts?' A critical reflection on definitions of failure for community health volunteers providing HIV self-testing in a community-based HIV/TB intervention study in urban Malawi
The category of community health worker applied within the context of health intervention trials has been promoted as a cost-effective approach to meeting study objectives across large populations, relying on the promotion of the concept of 'community belonging' to encourage altruistic volunteerism from community members to promote health. This community-based category of individuals is recruited to facilitate externally driven priorities defined…
Vertical Readings in Dante's Comedy
Vertical Readings in Dante's Comedy is a reappraisal of the poem by an international team of thirty-four scholars. Each vertical reading analyses three same-numbered cantos from the three canticles: Inferno i, Purgatorio i and Paradiso i; Inferno ii, Purgatorio ii and Paradiso ii; etc. Although scholars have suggested before that there are correspondences between same-numbered cantos that beg to be explored, this is the first time that the approa…
Costs of accessing HIV testing services among rural Malawi communities
HIV testing is free in Malawi, but users may still incur costs that can deter or delay them accessing these services. We sought to identify and quantify these costs among HIV testing service clients in Malawi. We asked residents of communities participating in a cluster randomised trial investigating the impact of HIV self-testing about their past HIV testing experiences and the direct non-medical and indirect costs incurred to access HIV testing…
The effectiveness and cost-effectiveness of community-based lay distribution of HIV self-tests in increasing uptake of HIV testing among adults in rural Malawi and rural and peri-urban Zambia
Clinicaltrials.gov, Malawi: NCT02718274 , 18 March 2016; Zambia: NCT02793804 , 3 June 2016. Protocol date: 21 February 2018
Measuring sexual behaviour in Malawi
Diaries may therefore have higher validity for sensitive behaviour reporting and thus be the preferred method in similar African contexts in measuring sexual behaviours
Discordance, Disclosure and Normative Gender Roles
A community-based HIV self-testing study in Blantyre, Malawi demonstrated that not all individuals living in couples tested with their partner. We describe factors dissuading individuals in couples from self-testing with their partner. Data were drawn from qualitative study exploring consequences of HIV self-testing within couples. In-depth interviews were conducted with 33 individuals living in couples who tested alone. Participants expressed fe…
Missing men with tuberculosis
Tuberculosis (TB) is treatable but is the leading infectious cause of death worldwide, with men over-represented in some key aspects of the disease burden. Men’s TB epidemiological scenario occurs within a wider public health and historical context, including their prior sidelining in health discussions. Differences are however noticeable in how some Western countries and high TB and HIV burden low and middle-income countries (LMIC) including in …
Use and awareness of and willingness to self-test for HIV
In 2015-16, many Malawian and Zimbabwean men had never tested for HIV. Despite low awareness and minimal HIVST experience, willingness to self-test was high among Zimbabwean men, especially older men with moderate-to-high HIV-related sexual risk. These data provide a valuable baseline against which to investigate population-level uptake of HIVST as programmes scale up. Programmes introducing, or planning to introduce, HIVST should consider includ…
Does community-based distribution of HIV self-tests increase uptake of HIV testing? Results of pair-matched cluster randomised trial in Zambia
OBJECTIVES: Ending HIV by 2030 is a global priority. Achieving this requires alternative HIV testing strategies, such as HIV self-testing (HIVST) to reach all individuals with HIV testing services (HTS). We present the results of a trial evaluating the impact of community-based distribution of HIVST in community and facility settings on the uptake of HTS in rural and urban Zambia. DESIGN: Pair-matched cluster randomised trial. METHODS: In catchme…
Innovative demand creation strategies to increase voluntary medical male circumcision uptake
INTRODUCTION: Reaching men aged 20-35 years, the group at greatest risk of HIV, with voluntary medical male circumcision (VMMC) remains a challenge. We assessed the impact of two VMMC demand creation approaches targeting this age group in a randomised controlled trial (RCT). METHODS: We conducted a 2×2 factorial RCT comparing arms with and without two interventions: (1) standard demand creation augmented by human-centred design (HCD)-informed app…
ART initiations following community-based distribution of HIV self-tests
INTRODUCTION: Measuring linkage after community-based testing, particularly HIV self-testing (HIVST), is challenging. Here, we use data from studies of community-based HIVST distribution, conducted within the STAR Initiative, to assess initiation of antiretroviral therapy (ART) and factors driving differences in linkage rates. METHODS: Five STAR studies evaluated HIVST implementation in Malawi, Zambia and Zimbabwe. New ART initiations during the …
Community-based HIV self-testing
BACKGROUND: HIV self-testing (HIVST) requires linkage to post-test services to maximise its benefits. We evaluated effect of supply-side incentivisation on linkage following community-based HIVST and evaluated time-trends in facility-based antiretroviral therapy (ART) initiations. METHODS: From August 2016 to August 2017 community-based distributors (CBDs) in 38 rural Zimbabwean communities distributed HIVST door-to-door in 19-25 day campaigns. C…
Effect of peer-distributed HIV self-test kits on demand for biomedical HIV prevention in rural KwaZulu-Natal, South Africa
Study objective We investigated two peer distribution models of HIV self-testing (HIVST) in HIV prevention demand creation compared with trained young community members (peer navigators). Methods We used restricted randomisation to allocate 24 peer navigator pairs (clusters) in KwaZulu-Natal 1:1:1: (1) standard of care ( SOC): peer navigators distributed clinic referrals, pre-exposure prophylaxis (PrEP) and antiretroviral therapy (ART) informatio…
Effect of door-to-door distribution of HIV self-testing kits on HIV testing and antiretroviral therapy initiation
INTRODUCTION: Reaching high coverage of HIV testing remains essential for HIV diagnosis, treatment and prevention. We evaluated the effectiveness and safety of door-to-door distribution of HIV self-testing (HIVST) kits in rural Malawi. METHODS: This cluster randomised trial, conducted between September 2016 and January 2018, used restricted 1:1 randomisation to allocate 22 health facilities and their defined areas to door-to-door HIVST alongside …
Pragmatic economic evaluation of community-led delivery of HIV self-testing in Malawi
INTRODUCTION: Community-based strategies can extend coverage of HIV testing and diagnose HIV at earlier stages of infection but can be costly to implement. We evaluated the costs and effects of community-led delivery of HIV self-testing (HIVST) in Mangochi District, Malawi. METHODS: This economic evaluation was based within a pragmatic cluster-randomised trial of 30 group village heads and their catchment areas comparing the community-led HIVST i…
Medicine (37 obras) · HIV/AIDS Research and Interventions (25 obras) · Environmental health (21 obras) · Family medicine (20 obras) · Nursing (18 obras) · Population (18 obras) · Adolescent Sexual and Reproductive Health (16 obras) · Public health (16 obras) · HIV Research and Treatment (13 obras) · Demography (12 obras)