Factors influencing the time to diagnosis and treatment of breast cancer among women in low- and middle-income countries: A systematic review

PURPOSE

Shorter time from symptoms recognition to diagnosis and timely treatment would be expected to improve the survival of patients with breast cancer (BC). This review identifies and summarizes evidence on time to diagnosis and treatment, and associated factors to inform an improved BC care pathways in Low- and Middle-Income Countries (LMICs).

METHODS

A systematic search was conducted in electronic databases including Medline, Embase, PsycINFO and Global Health, covering publications between January 1, 2010, and November 6, 2023. Inclusion criteria encompassed studies published in English from LMICs that reported on time from symptoms recognition to diagnosis and/or from diagnosis to treatment, as well as factors influencing these timelines. Study quality was assessed independently by two reviewers using a standard checklist. Pre-contact, post-contact and treatment intervals and delays in these intervals are presented. Barriers and facilitators for shorter time to diagnosis and treatment found by individual studies after adjusting with covariates are summarized.

RESULTS

The review identified 21 studies across 14 countries and found that BC cases took a longer time to diagnosis than to treatment. However, time to treatment also exceeded the World Health Organization (WHO) recommended period for optimal survival. There was inconsistency in terminology and benchmarks for defining delays in time intervals. Low socioeconomic status and place of residence emerged as frequent barriers, while initial contact with a private health facility or specialist was commonly reported as a facilitator for shorter time to diagnosis and treatment.

CONCLUSIONS

Guidelines or consensus recommendations are essential for defining the optimal time intervals to BC diagnosis and treatment. Our review supported WHO's Global Breast Cancer Initiative recommendations. Increasing public awareness, strengthening of healthcare professional's capacities, partial decentralization of diagnostic services and implementation of effective referral mechanisms are recommended to achieve a shorter time to diagnosis and treatment of BC in LMICs.

Cecal volvulus following appendectomy in a teenage patient: A case report

Patients mimicking appendicitis symptoms in a rural setting or those post-appendectomy, indicating cecal volvulus, should always be considered. Swift action can prevent catastrophic consequences.

Abstract

We present a case of a 14-year-old female who initially underwent open appendectomy for acute appendicitis and subsequently experienced symptoms of abdominal distention, vomiting, and fever. Her condition deteriorated following the appendectomy, despite a prior appendectomy for similar symptoms at a different facility. A computed tomography (CT) scan identified cecal volvulus as the underlying issue. This led to the performance of a laparotomy, cecopexy, and decompressive ileostomy. After six weeks, ileostomy closure was successfully carried out, and the patient currently enjoys good health. This case highlights the significance of considering uncommon factors as potential contributors to postoperative complications in young patients.

Perceived social support and compliance on stay-at-home order during COVID-19 emergency in Nepal: an evidence from web-based cross-sectional study

BACKGROUND

After COVID-19 was declared a Public Health Emergency of International Concern by WHO, several non-pharmaceutical interventions were adopted for containing the virus. Success to which largely depend upon citizens' compliance to these measures. There is growing body of evidence linking social support with health promoting behaviour. Hence, this research aimed to study the effects on compliance with stay-at-home order in relation to their perceived social support.

METHODS

A web-based cross-sectional study was conducted among adult participants aged 18 years and above residing in Bagmati Province, Nepal. A convenient non-probability sampling method was adopted to select the required number of samples. The questionnaire was developed through an extensive review of literature, and consultations with the research advisor, subject experts, as well as peers and converted to online survey form using Google Forms. Perceived social support was measured using the Multidimensional Scale of Perceived Social Support (MSPSS) scale whereas compliance was assessed using a single screening question. Statistical analysis was performed using SPSS version 20 involving both the descriptive and inferential statistics.

RESULTS

Two fifth (40.2%) of the participants reported poor compliance with stay-at-home order which was found higher among participants who were not vaccinated against COVID-19 compared to those vaccinated (p value < 0.05). A significant difference was observed between sex and perceived support (p value < 0.05) with higher proportion (80.8%) of female participants reporting perceived support from family, friends, and significant others in comparison to male participants.

CONCLUSION

Overall, the results of this study suggest that the perceived support from family is higher compared to others. Further evidence might be helpful to understand contextual factors on compliance with public health measures. Tailoring behaviour change messages as per the community needs would help the response in such emergencies. The findings from this study might be useful as one of the evidence base for formulating plans and policy during emergencies of similar nature.

EFFICACY OF AUTOLOGOUS STEM CELL TRANSPLANTATION IN ADULT BURKITT/BURKITT-LIKE LYMPHOMA: A SYSTEMATIC REVIEW

BACKGROUND

Burkitt and Burkitt like lymphoma (BL/BLL) are highly proliferative germinal or post-germinal B cell tumors. Few studies have evaluated the impact of autologous stem cell transplantation (ASCT) on disease outcomes.

AIM

We performed a systematic review to analyze the efficacy of ASCT as frontline consolidation and for treatment of relapsed/refractory cases in adult BL/BLL.

MATERIALS AND METHODS

Eligible studies with clear outcome measures on the efficacy of ASCT in adult patients with BL/BLL were identified through systematic search. The overall survival (OS), progression-free survival (PFS), complete response (CR), partial response (PR), and progression/relapse were used to assess the efficacy.

RESULTS

For patients who underwent ASCT in first CR, 5-year PFS and OS ranged between 70-78% and 70-83% respectively. For relapsed/refractory disease, 5-year PFS and OS were 27% and 31%, respectively. Patients undergoing ASCT for chemoresistant disease fared poorly with 3-year OS of 7% vs 37% for chemosensitive disease (p ≤ 0.00001). The overall response rate to ASCT for patients transplanted in first CR ranged between 71% and 93% and was 37% for patients who were transplanted in disease status other than first CR. Disease progression/relapse was observed in 16-29% of the patients transplanted in first CR, and 55% to 60% in relapsed disease.

CONCLUSION

We found insufficient evidence to support ASCT over chemotherapy alone in the first remission for adult BL/BLL. Evidence supports guidelines recommending ASCT for chemosensitive disease but suggests there is no benefit to ASCT for chemoresistant disease.

Cancer Incidence, Mortality, Years of Life Lost, Years Lived With Disability, and Disability-Adjusted Life Years for 29 Cancer Groups From 2010 to 2019: A Systematic Analysis for the Global Burden of Disease Study 2019

IMPORTANCE

The Global Burden of Diseases, Injuries, and Risk Factors Study 2019 (GBD 2019) provided systematic estimates of incidence, morbidity, and mortality to inform local and international efforts toward reducing cancer burden.

OBJECTIVE

To estimate cancer burden and trends globally for 204 countries and territories and by Sociodemographic Index (SDI) quintiles from 2010 to 2019.

EVIDENCE REVIEW

The GBD 2019 estimation methods were used to describe cancer incidence, mortality, years lived with disability, years of life lost, and disability-adjusted life years (DALYs) in 2019 and over the past decade. Estimates are also provided by quintiles of the SDI, a composite measure of educational attainment, income per capita, and total fertility rate for those younger than 25 years. Estimates include 95% uncertainty intervals (UIs).

FINDINGS

In 2019, there were an estimated 23.6 million (95% UI, 22.2-24.9 million) new cancer cases (17.2 million when excluding nonmelanoma skin cancer) and 10.0 million (95% UI, 9.36-10.6 million) cancer deaths globally, with an estimated 250 million (235-264 million) DALYs due to cancer. Since 2010, these represented a 26.3% (95% UI, 20.3%-32.3%) increase in new cases, a 20.9% (95% UI, 14.2%-27.6%) increase in deaths, and a 16.0% (95% UI, 9.3%-22.8%) increase in DALYs. Among 22 groups of diseases and injuries in the GBD 2019 study, cancer was second only to cardiovascular diseases for the number of deaths, years of life lost, and DALYs globally in 2019. Cancer burden differed across SDI quintiles. The proportion of years lived with disability that contributed to DALYs increased with SDI, ranging from 1.4% (1.1%-1.8%) in the low SDI quintile to 5.7% (4.2%-7.1%) in the high SDI quintile. While the high SDI quintile had the highest number of new cases in 2019, the middle SDI quintile had the highest number of cancer deaths and DALYs. From 2010 to 2019, the largest percentage increase in the numbers of cases and deaths occurred in the low and low-middle SDI quintiles.

CONCLUSIONS AND RELEVANCE

The results of this systematic analysis suggest that the global burden of cancer is substantial and growing, with burden differing by SDI. These results provide comprehensive and comparable estimates that can potentially inform efforts toward equitable cancer control around the world.

The global burden of adolescent and young adult cancer in 2019: a systematic analysis for the Global Burden of Disease Study 2019

BACKGROUND

In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15-39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults.

METHODS

Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15-39 years to define adolescents and young adults.

FINDINGS

There were 1·19 million (95% UI 1·11-1·28) incident cancer cases and 396 000 (370 000-425 000) deaths due to cancer among people aged 15-39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59·6 [54·5-65·7] per 100 000 person-years) and high-middle SDI countries (53·2 [48·8-57·9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14·2 [12·9-15·6] per 100 000 person-years) and middle SDI (13·6 [12·6-14·8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23·5 million (21·9-25·2) DALYs to the global burden of disease, of which 2·7% (1·9-3·6) came from YLDs and 97·3% (96·4-98·1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally.

INTERPRETATION

Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts.

FUNDING

Bill & Melinda Gates Foundation, American Lebanese Syrian Associated Charities, St Baldrick's Foundation, and the National Cancer Institute.

Epidemiologic Pattern of Cancer in Kathmandu Valley, Nepal: Findings of Population-Based Cancer Registry, 2018

PURPOSE

Although cancer is an important and growing public health issue in Nepal, the country lacked any population-based cancer registry (PBCR) until 2018. In this study, we describe the establishment of the PBCR for the first time in Nepal and use the registry data to understand incidence, mortality, and patterns of cancer in the Kathmandu Valley (consisting of Kathmandu, Lalitpur, and Bhaktapur districts), which comprises 10.5% of the estimated 29 million population of Nepal in 2018.

MATERIALS AND METHODS

The PBCR collects information from facilities and communities through the active process. The facilities include cancer or general hospitals, pathology laboratories, hospice, and Ayurvedic centers. In the communities, the field enumerators or female community health volunteers collected the data from the households. In addition, the Social Security and Nursing Division under the Department of Health Services, which provides subsidy for cancer treatment of underprivileged patients, was another major source of data. The collected data were verified for residence, accuracy, and completeness and then entered and analyzed using CanReg5 software.

RESULTS

In the Kathmandu Valley, the PBCR registered 2,156 new cancer cases with overall age-adjusted incidence rate for all cancers of 95.7 per 100,000 population (95.3 for males and 98.1 for females). The age-adjusted mortality rate for males was 36.3 (n = 365) and for females 27.0 (n = 305) per 100,000 population. We found that the commonest cancers in males were lung and stomach, whereas in females, they were breast and lung cancer. Gallbladder cancer was among the top five common cancers in both sex.

CONCLUSION

These findings provide a milestone to understand the cancer burden in the country for the first time using the PBCR and will be helpful to develop and prioritize cancer control strategies.

Differences in cancer incidence and pattern between urban and rural Nepal: one-year experience from two population-based cancer registries

Variations in cancer incidence, mortality and pattern exist in rural and urban areas. Understanding these differences helps in developing targeted cancer prevention and control strategies. However, no previous studies have explored the differences in cancer demographics between the rural and urban areas of Nepal. The data of Kathmandu Valley (urban area) Population-Based Cancer Registry (PBCR) and Rukum (rural area) PBCR were analysed to identify the differences in cancer pattern in rural and urban areas. The age-adjusted incidence rate (AAR) in Kathmandu was higher than that in Rukum (1.6 times among males and 1.9 times among females). The top two leading sites in males were lungs and stomach in both the regions; however, the rates were higher in Kathmandu. The incidence rate for cancer of the urinary bladder among males in Kathmandu was particularly higher - 4.4 times that of Rukum. In females, the leading site of cancer in Kathmandu was breast, which was eight times higher compared to Rukum, whereas the incidence rate of cervix cancer in Kathmandu is 30% less than in Rukum. The incidence of tobacco-related cancer was found to be higher in Kathmandu compared to Rukum. These findings reveal the need for different policy priorities for cancer control in the urban versus rural regions of Nepal, based on the different demographics of cancer in the two areas. Similar studies from other regions of Nepal are needed to develop a targeted cancer control strategy.

Factors Associated with Chronic Obstructive Pulmonary Diseases in Nepal: Evidence from a Nationally Representative Population-Based Study

Background

The Global Burden of Diseases Study 2017 predicted that chronic obstructive pulmonary disease (COPD) is the second leading cause of death, the fourth leading cause of premature death, and the third cause for DALYs lost in Nepal. However, data on the population-based prevalence of COPD in Nepal are very limited. This study aims to assess the prevalence of COPD and factors associated with the occurrence of COPD in Nepal.

Methods

From a nationally representative, population-based cross-sectional study on chronic non-communicable diseases, the prevalence of COPD and its associated factors was determined. Of 12,557 participants aged over 20 years, 8945 participants completed a questionnaire and spirometry. Eligible participants were also asked to answer a COPD diagnostic questionnaire for screening COPD cases, and if needed underwent pre-bronchodilator and post-bronchodilator spirometry. COPD was defined as a post-bronchodilator FEV1/FVC (forced expiratory volume in 1 s/forced vital capacity) ratio of <0.70. Multivariate logistic regression was performed to identify factors associated with COPD. Sampling weights were used for all data analyses.

Results

The prevalence of COPD in Nepal was 11.7% (95% CI: 10.5% to 12.9 %), which increased with age, and higher in those with a low educational level, those who had smoked ≥50 pack-years, persons having a low body mass index (BMI), and residents of Karnali province. Multivariate analysis revealed that being aged 60 years and above, having a low BMI, low educational status, having smoked more than 50 pack-years, provincial distribution, and ethnicity were independent predictors of COPD.

Conclusion

COPD is a growing and serious public health issue in Nepal. Factor such as old age, cigarette smoking, low educational attainment, low BMI, ethnicity, and locality of residence (province-level variation) plays a vital role in the occurrence of COPD. Strategies aimed at targeting these risk factors through health promotion and education interventions are needed to decrease the burden of COPD.

Challenges and Way Forward for Establishing Population Based Cancer Registry in Nepal

Population Based Cancer Registry plays a crucial role in cancer control through identifying cancer incidence, mortality, pattern and trends over time in a particular population. The registry is in a very infancy stage in Nepal. During the process of establishing Population Based Cancer Registry in Nepal, the major challenges include adequate coverage of the cases, high cost of registration, sustainability along with expansion of the registry to other regions and non-linkage of Hospital Based Cancer Registry with Population Based Cancer Registry. However, the approach of mobilization of field enumerators at the end of year once had increased coverage of the cases. Similarly, the linkage of Population Based Cancer Registry with the existing Health Management and Information System will help in developing sustainable Population Based Cancer Registry and also provides an opportunity to increase coverage and expand it to other districts as well. Keywords: Challenges; Nepal; population based cancer registry; way forward.

Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering

A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of θ_{lab}=7.9° and a mean energy of 1.149 GeV. The asymmetry result is B_{n}=-5.194±0.067(stat)±0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (θ_{lab}→0) where they should be most reliable.

Fertility Desire and Its Determinants Among People Living with HIV in Antiretroviral Therapy Clinic of Teku Hospital, Nepal

Background

Pregnancy in people Living with HIV/AIDS (PLHIV) involves significant public health risks, including the risk of HIV transmission to uninfected partners and the fetus. Despite the growing importance of fertility issues for HIV-infected people, little is known about their fertility desires in Nepal. This study, therefore, aimed to determine the magnitude of and factors associated with the fertility desire of PLHIV.

Patients and Methods

A cross-sectional study was conducted among 280 PLHIV attending the antiretroviral therapy (ART) clinic in Teku Hospital, Nepal. A standard semi-structured questionnaire was administered to participants using systematic random sampling. Data were entered using Epi-data 3.1 and analyzed using SPSS software version 20.

Results

Out of the total participants, 12.1% desired to have a child. Among those having this desire, 44.1% had not decided when to have a child. Reasons for desiring a child were having no children (44.1%), wanting to have a child of different sex than the previous one (29.4%), followed by wanting to have another child (26.5%). Factors such as being male (COR: 3.1, 95% CI: 1.3-7.0), being ≤40 years of age (COR: 3.8, 95% CI: 1.5-9.4), higher age at marriage (COR: 7.7, 95% CI: 1.5-39.6), middle socio-economic status (COR: 3.5, 95% CI: 1.7-7.3), having no children (COR: 22.9, 95% CI: 8.6-60.8) or fewer children (COR: 74.8, 95% CI: 9.7-575.1), greater CD4 count (COR: 2.8, 95% CI: 1.3-5.9) and having moderate knowledge of prevention of mother-to-child transmission (COR: 5.4, 95% CI: 2.3-12.7) had higher odds of having fertility desire.

Conclusion

Around one in every ten participants had a desire for fertility despite their HIV status. This calls for special attention in promoting integrated services for HIV and reproductive health. It will be important to include counseling and other services for those with fertility desire alongside providing ART.

Factors Influencing Modern Contraceptive Use among Adolescents in Nepal

In Nepal, contraceptive use among married adolescents is low and has remained nearly stagnant since 2006, while little information is available about contraceptive use among unmarried adolescents. Nepal is committed to improve sexual and reproductive health rights among all the adolescents. Promoting modern contraceptive use especially among married adolescents is one of the key approaches in practice, to prevent HIV or sexual transmitted infections, avoid unintended pregnancy and sub-sequent unsafe abortion. In spite of these efforts, modern contraceptive use among married adolescents is not increasing. In this study, we aimed to review the prevalence and trends as well as factors influencing modern contraceptive use among both married and unmarried adolescents in Nepal. A review of existing published and unpublished articles, documents, and reports were conducted. An adapted and modified socio-ecological model was used to explore the factors influencing contraceptive use. Contraceptive use is persistently low among adolescents. Various interrelated factors like socio-cultural norms and traditions, lack of comprehensive knowledge on contraceptive methods among adolescents, inadequate adolescent friendly Services and health workers not having the competencies to work with adolescents, are the major influential factors that limit adolescents to seek and use contraceptive services and information. A multilevel approach is required to address the interrelated factors and to create an enabling environment in which adolescent are fully informed and equipped to make use of contraceptives and related services. For this to happen, Government and NGOs working on sexual and reproductive health rights have to work towards translating the existing policies into practice. Involving adolescents, their families and communities; equipping teachers to provide comprehensive sex education within school and sex education programme for out of school and enhancing the competencies of health workers to provide adolescent friendly services - all in line with the written policy - is urgently needed. Keywords: Adolescent; barriers; contraceptive; Nepal; SRHR.

A glimpse of gluons through deeply virtual compton scattering on the proton

The internal structure of nucleons (protons and neutrons) remains one of the greatest outstanding problems in modern nuclear physics. By scattering high-energy electrons off a proton we are able to resolve its fundamental constituents and probe their momenta and positions. Here we investigate the dynamics of quarks and gluons inside nucleons using deeply virtual Compton scattering (DVCS)-a highly virtual photon scatters off the proton, which subsequently radiates a photon. DVCS interferes with the Bethe-Heitler (BH) process, where the photon is emitted by the electron rather than the proton. We report herein the full determination of the BH-DVCS interference by exploiting the distinct energy dependences of the DVCS and BH amplitudes. In the regime where the scattering is expected to occur off a single quark, measurements show an intriguing sensitivity to gluons, the carriers of the strong interaction.

Rosenbluth Separation of the π^{0} Electroproduction Cross Section

We present deeply virtual π^{0} electroproduction cross-section measurements at x_{B}=0.36 and three different Q^{2} values ranging from 1.5 to 2  GeV^{2}, obtained from Jefferson Lab Hall A experiment E07-007. The Rosenbluth technique is used to separate the longitudinal and transverse responses. Results demonstrate that the cross section is dominated by its transverse component and, thus, is far from the asymptotic limit predicted by perturbative quantum chromodynamics. Nonetheless, an indication of a nonzero longitudinal contribution is provided by the measured interference term σ_{LT}. Results are compared with several models based on the leading-twist approach of generalized parton distributions (GPDs). In particular, a fair agreement is obtained with models in which the scattering amplitude includes convolution terms of chiral-odd (transversity) GPDs of the nucleon with the twist-3 pion distribution amplitude. This experiment, together with previous extensive unseparated measurements, provides strong support to the exciting idea that transversity GPDs can be accessed via neutral pion electroproduction in the high-Q^{2} regime.

Chemically and biologically-mediated fertilizing value of manure-derived biochar

This study evaluates the potential of manure-derived biochars in promoting plant growth and enhancing soil chemical and biological properties during a 150day pot experiment. Biochars from pyrolysis of poultry litter (PL) and swine manure (SM) at 400 and 600°C, and a commonly available wood chip (WC) biochar produced at high temperature (1000°C) were incorporated to silt-loam (SL) and sandy (SY) soils on a 2% dry soil weight basis. Ryegrass was sown and moisture was adjusted to 60% water filled pore space (WFPS). The PL400 and SM400 biochars significantly increased (p<0.05) shoot dry matter (DM) yields (SL soil) and enhanced nitrogen (N), phosphorus (P) and potassium (K) uptake by the plants in both soils, compared to the Control. All biochars significantly increased the soil carbon (C) contents compared to the Control. Total N contents were significantly greater for PL400 and PL600 treatments in both soils. The dehydrogenase activity (DA) significantly increased for PL400 and SM400 treatments and was positively correlated with the volatile matter (VM) contents of the biochars, while β-glucosidase activity (GA) decreased for the same treatments in both soils. All biochars significantly shifted (p≤0.05) the bacterial community structure compared to the Control. This study suggests that pyrolysis of animal manures can produce a biochar that acts as both soil amendment and an organic fertilizer as proven by increased NPK uptake, positive liming effect and high soil nutrient availability, while WC biochar could work only in combination with fertilizers (organic as well as mineral).

Measurement of the Target-Normal Single-Spin Asymmetry in Quasielastic Scattering from the Reaction (3)He(↑)(e,e')

We report the first measurement of the target single-spin asymmetry, A(y), in quasielastic scattering from the inclusive reaction (3)He(↑)(e,e') on a (3)He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A nonzero A(y) can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the substructure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q(2)=0.13, 0.46, and 0.97  GeV(2). These measurements demonstrate, for the first time, that the (3)He asymmetry is clearly nonzero and negative at the 4σ-9σ level. Using measured proton-to-(3)He cross-section ratios and the effective polarization approximation, neutron asymmetries of -(1-3)% were obtained. The neutron asymmetry at high Q(2) is related to moments of the generalized parton distributions (GPDs). Our measured neutron asymmetry at Q(2)=0.97  GeV(2) agrees well with a prediction based on two-photon exchange using a GPD model and thus provides a new, independent constraint on these distributions.

Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton

Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scattering polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θ_{cm}^{p}=70°. The longitudinal transfer K_{LL}, measured to be 0.645±0.059±0.048, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is ~3 times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.

Measurement of double-polarization asymmetries in the quasielastic (3)He[→](e[→],e(')d) process

We present a precise measurement of double-polarization asymmetries in the ^{3}He[over →](e[over →],e^{'}d) reaction. This particular process is a uniquely sensitive probe of hadron dynamics in ^{3}He and the structure of the underlying electromagnetic currents. The measurements have been performed in and around quasielastic kinematics at Q^{2}=0.25(GeV/c)^{2} for missing momenta up to 270  MeV/c. The asymmetries are in fair agreement with the state-of-the-art calculations in terms of their functional dependencies on p_{m} and ω, but are systematically offset. Beyond the region of the quasielastic peak, the discrepancies become even more pronounced. Thus, our measurements have been able to reveal deficiencies in the most sophisticated calculations of the three-body nuclear system, and indicate that further refinement in the treatment of their two-and/or three-body dynamics is required.

Precision measurement of the neutron twist-3 matrix element d(2)(n): probing color forces

Double-spin asymmetries and absolute cross sections were measured at large Bjorken x  (0.25≤x≤0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized (3)He target. In this dedicated experiment, the spin structure function g(2)((3)He) was determined with precision at large x, and the neutron twist-3 matrix element d(2)(n) was measured at ⟨Q(2)⟩ of 3.21 and 4.32  GeV(2)/c(2), with an absolute precision of about 10(-5). Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at ⟨Q(2)⟩=5  GeV(2)/c(2). Combining d(2)(n) and a newly extracted twist-4 matrix element f(2)(n), the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 30  MeV/fm in magnitude.

Measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the reaction (3)He(↑)(e,e')X

We report the first measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the inclusive reaction 3)He(↑)(e,e')X on a polarized (3)He gas target. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation but can be nonzero if two-photon-exchange contributions are included. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.7<W<2.9  GeV, 1.0<Q(2)<4.0  GeV(2) and 0.16<x<0.65. Neutron asymmetries were extracted using the effective nucleon polarization and measured proton-to-(3)He cross-section ratios. The measured neutron asymmetries are negative with an average value of (-1.09±0.38)×10(-2) for invariant mass W>2  GeV, which is nonzero at the 2.89σ level. Our measured asymmetry agrees both in sign and magnitude with a two-photon-exchange model prediction that uses input from the Sivers transverse momentum distribution obtained from semi-inclusive deep-inelastic scattering.

Probing the repulsive core of the nucleon-nucleon interaction via the (4)He(e,e'pN) triple-coincidence reaction

We studied simultaneously the (4)He(e,e'p), (4)He(e,e'pp), and (4)He(e,e'pn) reactions at Q(2)=2(GeV/c)(2) and x(B)>1, for an (e,e'p) missing-momentum range of 400 to 830  MeV/c. The knocked-out proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual A=2 system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum, in a region where the nucleon-nucleon (NN) force is expected to change from predominantly tensor to repulsive. The abundance of neutron-proton pairs is reduced as the nucleon momentum increases beyond ∼500  MeV/c. The extracted fraction of proton-proton pairs is small and almost independent of the missing momentum. Our data are compared with calculations of two-nucleon momentum distributions in (4)He and discussed in the context of probing the elusive repulsive component of the NN force.

First determination of the weak charge of the proton

The Q(weak) experiment has measured the parity-violating asymmetry in ep elastic scattering at Q(2)=0.025(GeV/c)(2), employing 145 μA of 89% longitudinally polarized electrons on a 34.4 cm long liquid hydrogen target at Jefferson Lab. The results of the experiment's commissioning run, constituting approximately 4% of the data collected in the experiment, are reported here. From these initial results, the measured asymmetry is A(ep)=-279±35 (stat) ± 31 (syst) ppb, which is the smallest and most precise asymmetry ever measured in ep scattering. The small Q(2) of this experiment has made possible the first determination of the weak charge of the proton Q(W)(p) by incorporating earlier parity-violating electron scattering (PVES) data at higher Q(2) to constrain hadronic corrections. The value of Q(W)(p) obtained in this way is Q(W)(p)(PVES)=0.064±0.012, which is in good agreement with the standard model prediction of Q(W)(p)(SM)=0.0710±0.0007. When this result is further combined with the Cs atomic parity violation (APV) measurement, significant constraints on the weak charges of the up and down quarks can also be extracted. That PVES+APV analysis reveals the neutron's weak charge to be Q(W)(n)(PVES+APV)=-0.975±0.010.

Measurements of parity-violating asymmetries in electron-deuteron scattering in the nucleon resonance region

We report on parity-violating asymmetries in the nucleon resonance region measured using inclusive inelastic scattering of 5-6 GeV longitudinally polarized electrons off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the Δ(1232). They provide a verification of quark-hadron duality-the equivalence of the quark- and hadron-based pictures of the nucleon-at the (10-15)% level in this electroweak observable, which is dominated by contributions from the nucleon electroweak γZ interference structure functions. In addition, the results provide constraints on nucleon resonance models relevant for calculating background corrections to elastic parity-violating electron scattering measurements.

Hard two-body photodisintegration of 3He

We have measured cross sections for the γ(3)He → pd reaction at photon energies of 0.4-1.4 GeV and a center-of-mass angle of 90°. We observe dimensional scaling above 0.7 GeV at this center-of-mass angle. This is the first observation of dimensional scaling in the photodisintegration of a nucleus heavier than the deuteron.

Measurement of the neutron radius of 208Pb through parity violation in electron scattering

We report the first measurement of the parity-violating asymmetry A(PV) in the elastic scattering of polarized electrons from 208Pb. A(PV) is sensitive to the radius of the neutron distribution (R(n)). The result A(PV)=0.656±0.060(stat)±0.014(syst) ppm corresponds to a difference between the radii of the neutron and proton distributions R(n)-R(p)=0.33(-0.18)(+0.16) fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.

New precision limit on the strange vector form factors of the proton

The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624  GeV2 and beam energy E(b) = 3.48  GeV to be A(PV) = -23.80 ± 0.78(stat) ± 0.36(syst) parts per million. This result is consistent with zero contribution of strange quarks to the combination of electric and magnetic form factors G(E)(s) + 0.517G(M)(s) = 0.003 ± 0.010(stat) ± 0.004(syst) ± 0.009(ff), where the third error is due to the limits of precision on the electromagnetic form factors and radiative corrections. With this measurement, the world data on strange contributions to nucleon form factors are seen to be consistent with zero and not more than a few percent of the proton form factors.

Beam-target double-spin asymmetry A{LT} in charged pion production from deep inelastic scattering on a transversely polarized {3}He target at 1.4<Q{2}<2.7 GeV{2}

We report the first measurement of the double-spin asymmetry A{LT} for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized {3}He target. The kinematics focused on the valence quark region, 0.16<x<0.35 with 1.4<Q{2}<2.7  GeV{2}. The corresponding neutron A{LT} asymmetries were extracted from the measured {3}He asymmetries and proton over {3}He cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function g{1T}{q} and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for π{-} production on {3}He and the neutron, while our π{+} asymmetries are consistent with zero.

Search for a new gauge boson in electron-nucleus fixed-target scattering by the APEX experiment

We present a search at the Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling α' to electrons. Such a particle A' can be produced in electron-nucleus fixed-target scattering and then decay to an e + e- pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175-250 MeV, found no evidence for an A'→ e+ e- reaction, and set an upper limit of α'/α ~/= 10(-6). Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.

Single spin asymmetries in charged pion production from semi-inclusive deep inelastic scattering on a transversely polarized 3He Target at Q2 = 1.4-2.7 GeV2

We report the first measurement of target single spin asymmetries in the semi-inclusive (3)He(e,e'π(±))X reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.16 < x < 0.35 with 1.4 < Q(2) < 2.7 GeV(2). The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The π(±) Collins moments for (3)He are consistent with zero, except for the π(+) moment at x = 0.35, which deviates from zero by 2.3σ. While the π(-) Sivers moments are consistent with zero, the π(+) Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and measured cross section ratios of proton to (3)He, and are largely consistent with the predictions of phenomenological fits and quark model calculations.

Search for effects beyond the born approximation in polarization transfer observables in e(over→)p elastic scattering

Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, G(E)/G(M), obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, we report measurements of polarization transfer observables in the elastic H(e[over →],e(')p[over →]) reaction for three different beam energies at a Q(2)=2.5  GeV(2), spanning a wide range of the kinematic parameter ε. The ratio R, which equals μ(p)G(E)/G(M) in the Born approximation, is found to be independent of ε at the 1.5% level. The ε dependence of the longitudinal polarization transfer component P(ℓ) shows an enhancement of (2.3±0.6)% relative to the Born approximation at large ε.

Recoil polarization measurements of the proton electromagnetic form factor ratio to Q2 = 8.5 GeV2

Among the most fundamental observables of nucleon structure, electromagnetic form factors are a crucial benchmark for modern calculations describing the strong interaction dynamics of the nucleon's quark constituents; indeed, recent proton data have attracted intense theoretical interest. In this Letter, we report new measurements of the proton electromagnetic form factor ratio using the recoil polarization method, at momentum transfers Q2=5.2, 6.7, and 8.5  GeV2. By extending the range of Q2 for which G(E)(p) is accurately determined by more than 50%, these measurements will provide significant constraints on models of nucleon structure in the nonperturbative regime.

High-resolution spectroscopy of Lambda16N by electroproduction

An experimental study of the (16)O(e,e'K(+))(Lambda)(16)N reaction has been performed at Jefferson Lab. A thin film of falling water was used as a target. This permitted a simultaneous measurement of the p(e,e'K(+))Lambda, Sigma(0) exclusive reactions and a precise calibration of the energy scale. A ground-state binding energy of 13.76+/-0.16 MeV was obtained for (Lambda)(16)N with better precision than previous measurements on the mirror hypernucleus (Lambda)(16)O. Precise energies have been determined for peaks arising from a Lambda in s and p orbits coupled to the p(1/2) and p(3/2) hole states of the (15)N core nucleus.

Deeply virtual compton scattering off the neutron

The present experiment exploits the interference between the deeply virtual Compton scattering (DVCS) and the Bethe-Heitler processes to extract the imaginary part of DVCS amplitudes on the neutron and on the deuteron from the helicity-dependent D(e,e'gamma)X cross section measured at Q2=1.9 GeV2 and xB=0.36. We extract a linear combination of generalized parton distributions (GPDs) particularly sensitive to E_{q}, the least constrained GPD. A model dependent constraint on the contribution of the up and down quarks to the nucleon spin is deduced.

Measurements of the proton elastic-form-factor ratio mu pG p E/G p M at low momentum transfer

High-precision measurements of the proton elastic form-factor ratio, mu pG p E/G p M, have been made at four-momentum transfer, Q2, values between 0.2 and 0.5 GeV2. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q2 range the deviation from unity is primarily due to G p E being smaller than expected.

Investigation of proton-proton short-range correlations via the 12C(e,e'pp) reaction

We investigated simultaneously the 12C(e,e'p) and 12C(e,e'pp) reactions at Q2=2 (GeV/c)2, xB=1.2, and in an (e, e'p) missing-momentum range from 300 to 600 MeV/c. At these kinematics, with a missing momentum greater than the Fermi momentum of nucleons in a nucleus and far from the delta excitation, short-range nucleon-nucleon correlations are predicted to dominate the reaction. For (9.5+/-2)% of the 12C(e,e'p) events, a recoiling partner proton was observed back-to-back to the 12C(e,e'p) missing-momentum vector, an experimental signature of correlations.

High resolution spectroscopy of (lambda)(12)B by electroproduction

An experiment measuring electroproduction of hypernuclei has been performed in hall A at Jefferson Lab on a 12C target. In order to increase counting rates and provide unambiguous kaon identification two superconducting septum magnets and a ring imaging Cherenkov detector were added to the hall A standard equipment. An unprecedented energy resolution of less than 700 keV FWHM has been achieved. Thus, the observed (Lambda)(12)B spectrum shows for the first time identifiable strength in the core-excited region between the ground-state s-wave Lambda peak and the 11 MeV p-wave Lambda peak.

Precision measurements of the nucleon strange form factors at Q2 approximately 0.1 GeV2

We report new measurements of the parity-violating asymmetry A(PV) in elastic scattering of 3 GeV electrons off hydrogen and 4He targets with <theta(lab)> approximately 6.0 degrees . The 4He result is A(PV)=(+6.40+/-0.23(stat)+/-0.12(syst))x10(-6). The hydrogen result is A(PV)=(-1.58+/-0.12(stat)+/-0.04(syst))x10(-6). These results significantly improve constraints on the electric and magnetic strange form factors G(E)(s) and G(M)(s). We extract G(E)(s)=0.002+/-0.014+/-0.007 at <Q(2)>=0.077 GeV2, and G(E)(s)+0.09G(M)(s)=0.007+/-0.011+/-0.006 at <Q(2)>=0.109 GeV2, providing new limits on the role of strange quarks in the nucleon charge and magnetization distributions.

Scaling tests of the cross section for deeply virtual Compton scattering

We present the first measurements of the e[over -->]p-->epgamma cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region. The Q(2) dependence (from 1.5 to 2.3 GeV(2)) of the helicity-dependent cross section indicates the twist-2 dominance of DVCS, proving that generalized parton distributions (GPDs) are accessible to experiment at moderate Q(2). The helicity-independent cross section is also measured at Q(2)=2.3 GeV(2). We present the first model-independent measurement of linear combinations of GPDs and GPD integrals up to the twist-3 approximation.

Parity-violating electron scattering from 4He and the strange electric form factor of the nucleon

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from 4He at an average scattering angle <theta(lab)> = 5.7 degrees and a four-momentum transfer Q2 = 0.091 GeV2 . From these data, for the first time, the strange electric form factor of the nucleon G(E)s can be isolated. The measured asymmetry of A(PV) = (6.72 +/- 0.84(stat) +/- 0.21(syst) x 10(-6) yields a value of G(E)s = -0.038 +/- 0.042(stat) +/- 0.010(syst), consistent with zero.

Preparation of alpha-(2,2-diphenylhydrazino)lactones and related compounds by radical cyclization: use of glyoxylic acid hydrazone derivatives

Glyoxylic acid diphenylhydrazone (2a) and the corresponding O-benzyloxime (2b) are easily esterified in high yield by beta-bromo alcohols. The resulting esters undergo radical cyclization to alpha-(2,2-diphenylhydrazino)- or alpha-[(phenylmethoxy)amino]lactones on treatment with tributyltin hydride. Esters for radical cyclization were also made using a beta-(phenylseleno) alcohol and an enol ether. Several derivatives of glyoxylic acid were evaluated, but none was as effective as 2a or 2b. The imine 28 was prepared by an indirect route; it undergoes radical cyclization with displacement of the nitrogen substituent (28 --> 30) so that an alpha-amino lactone can be generated by acid hydrolysis of the cyclization product.