Recent cover crop adoption is associated with small maize and soybean yield losses in the United States.

Cover crops are gaining traction in many agricultural regions, partly driven by increased public subsidies and by private markets for ecosystem services. These payments are motivated by environmental benefits, including improved soil health, reduced erosion, and increased soil organic carbon. However, previous work based on experimental plots or crop modeling indicates cover crops may reduce crop yields. It remains unclear, though, how recent cover crop adoption has affected productivity in commercial agricultural systems. Here we perform the first large-scale, field-level analysis of observed yield impacts from cover cropping as implemented across the US Corn Belt. We use validated satellite data products at sub-field scales to analyze maize and soybean yield outcomes for over 90,000 fields in 2019-2020. Because we lack data on cover crop species or timing, we seek to quantify the yield impacts of cover cropping as currently practiced in aggregate. Using causal forests analysis, we estimate an average maize yield loss of 5.5% on fields where cover crops were used for 3 or more years, compared with fields that did not adopt cover cropping. Maize yield losses were larger on fields with better soil ratings, cooler mid-season temperatures, and lower spring rainfall. For soybeans, average yield losses were 3.5%, with larger impacts on fields with warmer June temperatures, lower spring and late-season rainfall, and, to a lesser extent, better soils. Estimated impacts are consistent with multiple mechanisms indicated by experimental and simulation-based studies, including the effects of cover crops on nitrogen dynamics, water consumption, and soil oxygen depletion. Our results suggest a need to improve cover crop management to reduce yield penalties, and a potential need to target subsidies based on likely yield impacts. Ultimately, avoiding substantial yield penalties is important for realizing widespread adoption and associated benefits for water quality, erosion, soil carbon, and greenhouse gas emissions.

Symptomatic cysts of the pineal gland: stereotactic diagnosis and treatment of two cases and review of the literature.

We report two cases of pineal gland cysts, both in young girls, causing aqueductal stenosis and symptomatic hydrocephalus, which were diagnosed and treated by Talairach's stereotactic method. This procedure permitted aspiration of the cyst content, normalization of aqueductal stenosis, and a differential histological diagnosis. Postoperative computed tomographic scan examination showed a stable reduction of the cystic volume and a complete clearance of the hydrocephalus. At present, the two patients are clinically normal and are leading a productive life (follow-up, 42 and 40 mo). It is important that this kind of nonneoplastic lesion be identified, in order to avoid confusion with pineal tumors and possible inappropriate treatment. Pineal cysts rarely become symptomatic. Up to the present, only 27 symptomatic cases have been described in the literature. Of those, signs of intracystic bleeding were found in 17 of the 21 cases in which the cyst contents were known. Moreover, in our own two cases, numerous hemosiderin-laden macrophages were present in the cystic fluid. We think, therefore, that intracystic bleeding has been the determining factor for the occurrence of symptoms in most of these cases. The authors underline the advantages of this type of stereotactic management, which can provide both diagnosis and treatment and thus avoid the possible risks of surgical excision and/or of radiotherapy.

Calcified brain abscesses. Case report.

A surgically treated case of multiple contiguous brain abscesses at different stages of calcification is reported. The patient, a man 48 years old, had been suffering from epilepsy for 34 years and he was complaining of headaches and fever for 15 days when admitted to our clinic. The post-operative neurological recovery was good.

Median third ventricle meningioma. Case report.

A case of meningioma located in the median part of the third ventricle and revealed by autoptic examination in a patient who died for meningoencephalitis is reported.

Considerations on the operative results in a group of elderly neurosurgical patients.

536 patients from 60 to 84 years old, operated on for neurosurgical lesions, are evaluated with reference to post-operative mortality rate related to the type of pathology. 83 deaths (15.6%) occurred in this series. Mortality rate increases progressively with advancing age. It is outlined that the aged patients have lesser chances of surgical success, but the present data induce to consider with greater favour the outcome of these patients.

Optical-chiasmatic region epidermoid with a suprasellar and prepontina region cysticercosis.

The Authors report a case of epidermoid in the optical-chiasmatic region associated with a cysticercosis in the suprasellar and prepontal region. The patient was surgically treated with success: a bilobate cystic formation with ramifications adherent to the carotid siphon was found in front of optic nerves. Opening the arachnoid between the left optic nerve and carotid, a dysembriogenetic cystic formation was observed. Adherent to it there was the wall of a second parasitic cystic formation (probably cysticercosis) from which some small cysts slid away. After a review of the literature the Authors point out both the casual association of the two pathologies and the utility of C.T. scan in the diagnostic process of the above mentioned lesions.

Venous saving in olfactory meningioma's surgery.

Bifrontal craniotomy and interhemispherical approach, usually used to remove olfactory groove meningioma, does not allow a view of posterior pole, which is very important in the surgical management of this neoplasm, and, provides for an anatomical sacrifice of frontal bridging veins, not without complications as a result of venous infarction. From 1975 the pterional approach was performed on 20 patients with olfactory meningioma, with good results in 90% of cases. This approach presents several advantages over bifrontal craniotomy and, in order to minimise surgical damage, it avoids planned sacrifice of venous vessels.

Basal meningiomas. A retrospective study of 139 surgical cases.

BACKGROUND: Basal meningiomas represent a significant group of intracranial tumours. Their surgical treatment presents still today several difficulties since these tumours, as it is well known, may involve critical neurovascular structures. METHODS: This is a retrospective study of 139 consecutive cases of basal meningioma operated on in our institution during the last two decades. Meningiomas location: olfactory groove 20 cases; suprasellar region 22; anterior cranial fossa 6; sphenoid wing 37; cerebellopontine angle/clivus 21; tentorium 26. In most cases the meningioma was larger than 5 cm. The tumour was completely removed (grade I-II of Simpson classification) in 111 cases (79.9%). The authors dwell upon some clinical and surgical aspects of prevailing groups (olfactory, suprasellar, sphenoidal, petroclival and tentorial meningiomas); regarding to operative procedures, the authors in particular emphasise the usefulness of the pterional approach to remove olfactory groove meningiomas and of the combined supra- and infratentorial approach, with preservation of transverse and sigmoid sinuses, to remove petroclival meningiomas. RESULTS: The surgery was followed by excellent or good results in 115 cases (82.7%): patients having a normal life with a score 80-100 of Karnofsky scale; poor outcome occurred in 5.8% of cases, postoperatively died 16 patients (mortality rate 11.5%). Tumour recurrence occurred in 7 cases. CONCLUSIONS: Based on their experience and on analysis of the reviewed literature, the authors conclude that advances in microsurgical techniques and in neuroradiological imaging have radically improved the outcome so that today basal meningiomas can be successfully treated in most cases.

Ossified epidural hematoma. Report of a case with epilepsy.

A case of post-traumatic ossified epidural hematoma associated to epileptic seizures is reported. After surgical treatment complete recovery was obtained.

[Thrombosis of the vein of Labbé with haemorrhagic cerebral infarction (author's transl)]. / Infarctus cérébral hémorragique par thrombose de la veine de Labbé.

A case of carbon monoxide poisoning with thrombosis of the vein of Labbé and an haemorrhagic cerebral infarct is reported. The mechanisms of the lesions, their diagnosis and treatment are reveiwed. The points are made that the cerebral lesion is an expanding one and that its surgical ablation should be considered.

[Traumatic obliteration of the middle cerebral artery. Pathogenic considerations]. / Oblitération traumatique de l'artère cérébrale moyenne. Considérations pathogéniques

Report on one case of traumatic obliteration of the middle cerebral artery together with a review of the pathogenetic theories published till presently on this subject. Three factors are retained in the case object of the present work: --compression of the arterial wall in the Sylvian fissure, as a consequence of contusion and cerebral edema, --disorders in the platelets aggregation, --high blood pressure.

[Giant aneurysm of the sylvian artery in a 4-year old child (exeresis, remission)]. / Anévrysme géant de lártère sylvienne chez un enfant de quatre ans (exérèse, guérison)

The AA. describe a case of a giant aneurysm 6 centimeters in diameter in a child of 4 years old. The lesion was made evident on the occasion of an hemorrhage that has caused an insular hematoma. The patient has undergone an operation with favourable outcome. The lack of neurologic symtomatology until the moment of the hemorrhage lead the AA. to think that this lesion was of the notables proportions from the moment of birth, so that the cerebral parenchyma was modeled on it. Unlike others cases in litterature recogniset, the wall of the aneurysmatic bag did not present fibrotics thickenings, and besides the blood-clot included in it seemed histologicaly of recent formation.

[Experimental fetal hydrocephalus. Ventriculo-amniotic shunt]. / Hydrocéphalie foetale expérimentale. Shunt ventriculo-amniotique.

When the original idea was conceived 8 years ago to develop a surgical technique for the treatment of fetal hydrocephalus, the pathway towards prenatal surgery for this affection was totally unexplored. The operation appeared to be feasible because of the possibility of a ventriculo-amniotic shunt. The most important steps in our experimental studies in the ewe were creation of a fetal hydrocephalus by injection of a suspension of kaolin powder into cisterna magna; the treatment of the hydrocephalus by a mini-ventriculo-amniotic shunt, by cutting the cardiac end of a low pressure Pudenz pediatric catheter. Lambs were delivered by Cesarean two weeks before end of gestation. Coronal sections of brains of control and treated lambs showed reduction in hydrocephalus in the latter. These findings were the basis for the application of the method to treatment of human fetal hydrocephalus.