Contract farming and rural transformation: Evidence from a field experiment in Benin.

Contract farming has emerged as a popular mechanism to encourage vertical coordination in developing country agriculture. Yet, there is a lack of consensus on its ability to spur structural transformation in rural economies. We present results from a field experiment on contract farming for rice production in Benin. While all contracts have positive effects on welfare and productivity measures, we find that the simplest contract has impacts nearly as large as contracts with additional attributes. This suggests that once price risk is resolved through the offer of a fixed-price contract, farmers are able to address other constraints on their own.

Adoption of climate-resilient groundnut varieties increases agricultural production, consumption, and smallholder commercialization in West Africa.

As part of the climate-smart agriculture approach, the adoption of climate-resilient crop varieties has the potential to build farmers' climate resilience but could also induce agricultural transformation in developing nations. We investigate the relationship between adoption of climate-resilient groundnut varieties and production, consumption, and smallholder commercialization using panel data from Ghana, Mali, and Nigeria. We find adoption of climate-resilient groundnut varieties to increase smallholder production, consumption, and commercialization. The biggest adoption impact gains are observed under the sustained use of these climate-resilient varieties. We show that adoption benefits all households, but the biggest gains are found among smaller producers, suggesting that adoption is inclusive. Furthermore, we provide suggestive evidence that yield increases could explain commercialization, although household consumption also matters. We conclude that adoption of climate-resilient groundnut varieties can at least partially reduce production constraints and promote smallholder consumption and commercialization, with implications for agricultural transformation.

Farmer advisory systems and pesticide use in legume-based systems in West Africa.

Despite the adverse effects of pesticides on the environment and human health, they are a key ingredient in boosting agricultural productivity as a way of meeting global food demand. While global levels of pesticides are towering in high-income countries, pesticide use in many parts of Africa remains low, with significant impacts on agricultural productivity and food production. We use a rich longitudinal dataset to examine the relationship between farmer advisory systems and pesticide use in legume-based production systems in Ghana, Mali, and Nigeria. We find that farmers who are advised by private extension systems are approximately 8 % more likely to use pesticides at an extensive level. They also use pesticides more intensively (41 %). On the other hand, farmers advised by public extension systems are about 5 % more likely to extensively use pesticides. These farmers are observed to reduce the intensive use of pesticides by about 14 %. Furthermore, we also show that farmers advised by joint private-public extension systems are about 4 % more likely to use pesticides as well as reduce their intensity of use by approximately 11 %. At the various country levels, there exists significant heterogeneity in the relationship between advisory systems and pesticide use, suggesting that context matters. Of course, the pesticide regulatory systems and the institutional environments in these countries vary greatly. Given these findings, our study offers key entry and leveraging points for increasing pesticide use at levels that limit their environmental and human effects but may ascertain increased agricultural productivity and food production.

Wolbachia modification of sperm does not always require residence within developing sperm.

Wolbachia are maternally inherited intracellular bacteria known to manipulate the reproduction of their arthropod hosts. Wolbachia commonly affect the sperm of infected arthropods. Wolbachia-modified sperm cannot successfully fertilize unless the female is infected with the same Wolbachia type. A study of spermatogenesis in the parasitic wasp Nasonia vitripennis reveals that Wolbachia are not required in individual spermatocytes or spermatids to modify sperm. In N. vitripennis, Wolbachia modify nearly all sperm, but are found only in approximately 28% of developing sperm, and are also found in surrounding cyst and sheath cells. In the beetle Chelymorpha alternans, Wolbachia can modify up to 90% of sperm, but were never observed within the developing sperm or within the surrounding cyst cells; they were abundant within the outer testis sheath. We conclude that the residence within a developing sperm is not a prerequisite for Wolbachia-induced sperm modification, suggesting that Wolbachia modification of sperm may occur across multiple tissue membranes or act upstream of spermiogenesis.

[Computerized tomography-guided needle biopsy for the diagnosis of pulmonary nodules: analysis of a series of 41 patients]. / Ponction à visée diagnostique de nodules pulmonaires sous repérage scanographique: analyse d'une série de 41 patients.

This study was aimed at assessing percutaneous biopsy under computerized tomography (CT) guidance, its results in terms of diagnostic value, factors contributing to its complications or success, and its indications. Results obtained from a series of 41 patients and data from previous clinical trials were compared. Patients who were not eligible due to either poor physical condition or a tumor that could not be reached were not included into the study. Various factors, ie, the tumor location, the size of the lesion, the distance between the lesion and the thoracic wall, and the type (histological and/or cytological) of samples, were analyzed. Results were evaluated according to the disease evolution or pathological findings. Tumoral cells were found in 23 samples. Eighteen samples were negative for malignancy, with eight benign lesions and ten false negative. Complications that occurred just after the biopsy were recorded. Failures and complication factors were analyzed and compared to those already described. CT-guided needle biopsy is an admitted alternative to thoracotomy, even for small nodules deeply located. The use of this technique should be discussed when fiberoptic endoscopy leads to negative results. Various tumors cannot be reached using CT-guided needle biopsy and this technique is more efficacious for bulky nodules. The thickness of lung parenchyma passed through does not seem to change the risk of pneumothorax. The use of laser guidance might help locate the tumor with more accuracy.

[Value of echography in a case of polyorchidism]. / Intérêt de l'échographie dans un cas de polyorchidisme.

We report a case of polyorchidism diagnosed by scrotal ultrasonography and confirmed by surgery. Sixty eight cases have been reported in the literature.

[Blunt injury of the larynx by hanging. X-ray computed tomographic aspect]. / Traumatisme fermé du larynx par pendaison. Aspect scanographique à propos d'un cas.

The closed laryngeal traumas by attempt of hanging are rarely studied by medical imaging. The lesions are evaluated by fiberoptic endoscopy and CT scan. We report a case of complicated lesions of the larynx with rupture of the cricothyroid membrane, diagnosed by CT scan and we discuss the usefulness of this technique.

[Multiple calcified cerebral metastases revealing bronchial adenocarcinoma. Apropos of a case]. / Métastases cérébrales calcifiées multiples révélatrices d'un adénocarcinome bronchique. A propos d'un cas.

Calcified brain metastases are rare. They are unique or multiple. The primary site is lung, breast, gastro-intestinal tract, uterine cervix, bone or may be unidentified. It corresponds pathologically to an adenocarcinoma, a sarcoma or to a squamous cell carcinoma. We report a case of multiple calcified brain metastases discovered before primary tumour (bronchial adenocarcinoma), raising the problem of differential diagnosis resolved by stereotaxic brain biopsy.

Antiangiogenic properties of a novel shark cartilage extract: potential role in the treatment of psoriasis.

BACKGROUND: A number of inflammatory and immune diseases are associated with vascular changes. Psoriasis, as an example, is a common inflammatory skin disease with dilation of capillaries as an early histological change. In more developed psoriatic lesions there is proliferation of blood vessels and neovascularization. The use of agents that target these vascular changes represents a novel therapeutic strategy in the treatment of inflammatory diseases. Since cartilage is an avascular tissue, it has been hypothesized that there may be factors found in cartilage that inhibit blood vessel formation. OBJECTIVE: The objectives of this study were 1) to determine whether extracts of cartilage could inhibit angiogenesis, and 2) since altered angiogenesis is associated with certain diseases, including psoriasis, to examine whether inhibition of angiogenesis could potentially contribute to the treatment of psoriasis. METHODS: Extracts of shark cartilage were prepared by homogenization and ultrafiltration to derive the active agent termed AE -941. This agent was tested for antiangiogenesis activity using the embryonic vascularization test, which is a modification of the ex vivo chick embryo culture (CAM). Since one of the first steps in angiogenesis is degradation by metalloproteinases of the basement membrane of capillaries, AE -941 was tested for collagenase activity using a fluorogenic peptide substrate. Anti-inflammatory properties were tested using a cutaneous irritation model in humans. RESULTS: A dose dependent inhibition in embryonic neovascularization as well as in collagenase activity by AE -941 was demonstrated. When test compounds were applied on the forearms of test subjects, AE -941 was shown to have anti-inflammatory properties. Anecdotal data suggested that topical AE -941 had a beneficial effect in psoriasis. CONCLUSION: Our results show that AE -941 has anti-angiogenic and anti-inflammatory properties. Antiangiogenesis agents such as AE -941 provide an entirely new class of agents to treat cutaneous and systemic diseases associated with altered vascularity.