Species Richness, Density, Activity, and Composition of Ground-dwelling Ants in the Humid Forest Zone of Southern Cameroon: Role of Vegetation Cover and Abiotic Factors.

The destruction of natural habitats is among the major factors responsible for the decrease in species diversity and distribution. This study focused on the effect of vegetation and its interaction with the season on ant species richness, density, activity, and composition in the three dominant habitats - forest, fallow, and mixed crop field - prevailing in southern Cameroon. Ants were sampled using two sampling techniques -pitfall trap and quadrat - in fallows, forest, and mixed crop fields from May 2007 to April 2008. Average ant species richness did not differ between fallow and forest, but the number of species in both habitats was higher compared with mixed-crop field. Species richness was also higher during the short dry season compared with other seasons. Species density was higher in mixed-crop field and in the long dry season. Species activity was similar in the three habitats, but it was higher during the long-wet season. Species richness, activity, and density were lower at low altitude. Vegetation and season affected the composition of ant species, but not the interaction between the two factors. The highest dissimilarity index was observed between mixed crop-field and forest while between seasons, it was between the short-wet and the long dry season. These results suggest that vegetation cover and abiotic factors interact to determine the distribution, density, activity, and composition of ant species. Identifying key drivers among environmental factors could help to understand the response of species to the variation of those factors in the context of climate change.

Results from a real-time dosimetry study during left atrial ablations performed with ultra-low dose radiation settings.

BACKGROUND: Three-dimensional mapping systems and the use of ultra-low dose radiation protocols have supported minimization of radiation dose during left atrial ablation procedures. By using optimal shielding, scattered radiation reaching the operator can be further reduced. This prospective study was designed to determine the remaining operator radiation exposure during left atrial catheter ablations using real-time dosimetry. METHODS: Radiation dose was recorded using real-time digital dosimetry badges outside the lead apron during 201 consecutive left atrial fibrillation ablation procedures. All procedures were performed using the same X­ray system (Siemens Healthineers Artis dBc; Siemens Healthcare AG, Erlangen, Germany) programmed with ultra-low dose radiation settings including a low frame rate (two frames per second), maximum copper filtration, and an optimized detector dose. To reduce scattered radiation to the operators, table-suspended lead curtains, ceiling-suspended leaded plastic shields, and radiation-absorbing shields on the patient were positioned in an overlapping configuration. RESULTS: The 201 procedures included 139 (69%) pulmonary vein isolations (PVI) (20 cryoballoon ablations, 119 radiofrequency ablations, with 35 cases receiving additional ablation of the cavotricuspid isthmus) and 62 (31%) PVI plus further left atrial substrate ablation. Mean radiation dose measured as dose area product for all procedures was 128.09 ± 187.87 cGy ∙ cm2 with a mean fluoroscopy duration of 9.4 ± 8.7 min. Real-time dosimetry showed very low average operator doses of 0.52 ± 0.10 µSv. A subanalysis of 51 (25%) procedures showed that the radiation burden for the operator was highest during pulmonary vein angiography. CONCLUSION: The use of ultra-low dose radiation protocols in combination with optimized shielding results in extremely low scattered radiation reaching the operator.

"Time Variable Earth Gravity Field Models From the First Spaceborne Laser Ranging Interferometer".

The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO), launched May 22, 2018 and collecting science data since June 2018, is extending the 15-year data record of Earth mass change established by its predecessor GRACE mission (2002-2017). The GRACE-FO satellites carry onboard a novel technology demonstration instrument for intersatellite ranging, the Laser Ranging Interferometer (LRI), in addition to the microwave interferometer (MWI) carried on GRACE. The LRI has out-performed its in-orbit performance requirements both in terms of accuracy as well as the duration of tracking. Here, we compare and validate LRI-based gravity solutions for January 2019 to September 2020 against the MWI solutions. The comparison between the two sets of gravity solutions shows great similarities in general and nearly perfect consistency at a large hydrologic basin spatial scale (100,000 km2 and above), commonly viewed as the spatial resolution established by GRACE. The comparison in the spectral domain shows differences at the higher degrees of the spectrum, with lower error in the zonal and near zonal terms for the LRI solutions. We conclude that the LRI observations can be used to recover time-varying gravity signals to at least the level of accuracy established by the MWI-based solutions. This is a promising finding, especially when considering the benefits of using the LRI over the MWI, such as the great stability of the instrument and the low occurrence of instrument reboot events.

Selective flowers to attract and enhance Telenomus laeviceps (Hymenoptera: Scelionidae): a released biocontrol agent of Mamestra brassicae (Lepidoptera: Noctuidae).

The importance of the right food source for the survival and reproduction of certain insect species is well documented. In the case of biocontrol agents, this is even more important in order to reach a high predation or parasitation performance. The egg parasitoid Telenomus laeviceps (Förster, 1861) (Hymenoptera: Scelionidae) is a promising candidate for mass release as a biological control agent of the cabbage moth Mamestra brassicae (Linnaeus, 1758) (Lepidoptera: Noctuidae). However, adult T. laeviceps need a sugar-rich food source to increase their parasitation performance and produce a good amount of female offspring. Released biocontrol agents were shown to benefit from conservation biocontrol, which includes the provision of selected flowers as nectar resources for beneficial insects. In Switzerland, Centaurea cyanus L. (Asteraceae), Fagopyrum esculentum Moench (Polygonaceae) and Vicia sativa L. (Fabaceae) are successfully implemented in the field to attract and promote natural enemies of different cabbage pests. In this study, we investigated the potential of these selected flowers to attract and promote T. laeviceps under laboratory conditions. In Y-tube olfactometer experiments, we first tested whether the three nectar providing plant species are attractive to T. laeviceps. Furthermore, we assessed their effects on survival and parasitation performance of adult T. laeviceps. We found that flowers of F. esculentum and C. cyanus were attractive in contrast to V. sativa. Also fecundity and the number of female offspring produced were higher for females kept on F. esculentum and C. cyanus than on V. sativa. In contrast, survival was similar on all treatments. Our findings present a further key step towards the implementation of T. laeviceps as a biocontrol agent.

Incidence of MRI-detected brain lesions and neurocognitive function after electrical cardioversion in anticoagulated patients with persistent atrial fibrillation.

BACKGROUND: After electrical cardioversion (eCV) in patients with atrial fibrillation (AF), the risk for clinically apparent cerebral thromboembolism is increased in the subsequent weeks. To date, there is little evidence on the incidence of acute brain lesions (ABL) detected with cerebral magnetic resonance imaging (MRI) after eCV, in particular in patients treated with the Non-Vitamin K Antagonist oral anticoagulants (NOAC). AIMS: The aim of this pilot study was to evaluate the incidence of MRI-detected ABL, as well as the neuro-cognitive function after eCV in patients with persistent AF using NOACs as compared to phenprocoumon. METHODS AND RESULTS: 50 consecutive patients with persistent AF (mean age 69.6±3.5years, 26 male) were evaluated in this prospective study. Cerebral 3Tesla MRI and neuro-cognitive assessment using the National Institutes of Health Stroke Scale (NIHSS) score and the Montreal Cognitive Assessment Test (MoCA) were performed in all patients within 24h before eCV and after a median follow-up duration of 14days (Q1: 13, Q3: 19days). Patients were treated with an OAC for at least 4weeks after eCV and according to the CHA2DS2-Vasc-score thereafter. Thirty-nine patients were treated with NOACs (Dabigatran 10/50 [20%], Apixaban 21/50 [42%] and Rivaroxaban 8/50 [16]) and 11/50 patients with Phenprocoumon (22%). No patient developed ABL on cerebral MRI at the 2-week follow-up. Neurological as well as cognitive function were similar before and 2weeks after eCV (NIHSS-score: p=0.35; MoCa score: p=0.21). CONCLUSION: Electrical CV in patients with persistent AF, in particular when treated with NOACs, carries a low risk for the development of MRI-detected ABL or neurocognitive decline. CLINICAL TRIALS REGISTRATION: GermanClinicalTrialsRegister number: DRKS00010460.

[Right ventricular outflow tract tachycardia 30 years after surgical correction of tetralogy of Fallot]. / Rechtsventrikuläre Ausflusstrakt-Tachykardie 30 Jahre nach chirurgischer Fallot-Teratologie-Korrektur.

This case report describes a 31-year-old man with a sustained wide complex tachycardia with left bundle brunch block morphology after surgical repair of a tetralogy of Fallot. The tachycardia was inducible after orciprenaline administration after ventricular stimulation with one extra beat. In combination with the three-dimensional electroanatomic mapping system and pace mapping technique the origin of the tachycardia was identified at the lateral free wall of the right ventricular outflow tract tachycardia (RVOT) inferior of the pulmonary valve. Successful radiofrequency ablation was performed and the patient is still free from ventricular tachycardia.

Pain experience and functional outcome of inpatient versus outpatient anterior cruciate ligament reconstruction, an equivalence randomized controlled trial with 12 months follow-up.

BACKGROUND: Arthroscopic reconstruction of the anterior cruciate ligament (ACL) has traditionally been performed in an inpatient setting. Outpatient treatment may offer the advantages of cost reduction and higher patient satisfaction. HYPOTHESIS/PURPOSE: We investigated whether ACL reconstruction in an outpatient setting is equally safe as in an inpatient setting and whether comparable functional outcomes can be achieved. We hypothesized that the outcomes of outpatient ACL reconstruction result in similar outcomes as inpatient ACL reconstruction. STUDY DESIGN: A prospective randomized controlled trial was conducted at one centre. METHODS: Forty-six patients were randomized to outpatient treatment or a 2-day admission after ACL reconstruction. The functional outcome was evaluated with the Lysholm, Tegner and International Knee Documentation Committee scores. Safety of the procedures was judged according to pain experience and readmission rate. The duration of follow-up was 1 year after ACL reconstruction. The patients were provided with a simple postoperative analgesic protocol. The linear mixed effect model for repeated measures was used for testing the differences between the study groups. RESULTS: No significant differences were found between the study groups in all the outcome measures. No readmissions were recorded related to pain. One complication was recorded in the outpatient group versus three in the inpatient group. CONCLUSION: This study indicates that outpatient care after ACL reconstruction yields comparable functional results and postoperative pain experience as inpatient care and is a safe option. A simple analgesic protocol provides adequate pain relief during the postoperative phase. LEVEL OF EVIDENCE: I.

Beyond the Heisenberg model: anisotropic exchange interaction between a Cu-tetraazaporphyrin monolayer and Fe3O4(100).

The exchange coupling of a single spin localized at the central ion of Cu-tetraazaporphyrin on a magnetite(100) surface has been studied using x-ray magnetic circular dichroism (XMCD). Sum rule analysis of the XMCD spectra results in Cu spin and orbital magnetic moments as a function of the applied external field at low temperatures (20 K). The exchange coupling is positive for magnetization direction perpendicular to the surface (ferromagnetic) while it is negative for in-plane magnetization direction (antiferromagnetic). We attribute the anisotropy of the Heisenberg exchange coupling to an orbitally dependent exchange Hamiltonian.

Double exchange via t(2g) orbitals and the Jahn-Teller effect in ferromagnetic La0.7Sr0.3CoO3 probed by epitaxial strain.

The magnetic exchange in hole-doped ferromagnetic cobaltates is investigated by studying the magnetic and electronic properties of La0.7Sr0.3CoO3 films as a function of epitaxial strain. We found a strong-coupling double exchange mechanism between Co3+ (4t(2g)   2e(g)) and Co4+ (3t(2g)   2e(g)) high-spin states mediated by t(2g) electrons--in contrast to the moderate coupling provided by the e(g) exchange in manganites. The strong sensitivity of the Curie temperature TC to the bulk compression can be explained by the small bandwidth of the t(2g)-derived states. A strain-induced Jahn-Teller effect is likewise observed. The experimental results clarify the magnetic exchange mechanism in the cobaltates.

Magnetic proximity effect in YBa2Cu3O7/La(2/3)Ca(1/3)MnO3 and YBa2Cu3O7/LaMnO(3+δ) superlattices.

Using neutron reflectometry and resonant x-ray techniques we studied the magnetic proximity effect (MPE) in superlattices composed of superconducting YBa2Cu3O7 and ferromagnetic-metallic La0.67Ca0.33MnO3 or ferromagnetic-insulating LaMnO(3+δ). We find that the MPE strongly depends on the electronic state of the manganite layers, being pronounced for the ferromagnetic-metallic La0.67Ca0.33MnO3 and almost absent for ferromagnetic-insulating LaMnO(3+δ). We also detail the change of the magnetic depth profile due to the MPE and provide evidence for its intrinsic nature.

From interfaces to surfaces: soft x-ray spectromicroscopy investigations of diindenoperylene thin films on gold.

We present the results of photoemission electron microscopy investigations on diindenoperylene (DIP) thin films deposited on polycrystalline gold, prepared in order to have a roughness much larger than the molecular size. Our investigations revealed the ability of the DIP molecule to form well-organized films, exhibiting a different molecular orientation with respect to the already known λ and σ phases. In locally thicker film regions, the energy of the films is minimized by a molecular arrangement that has an asymptotic tendency to the σ phase.

Magnetic and structural properties of FeCr alloys.

Synergistic synchrotron x-ray absorption experiments using imaging magnetic microspectroscopy, x-ray magnetic circular dichroism, and ab initio calculations on FeCr alloys reveal that the Cr content strongly influences the ferromagnetic microstructure and the Fe magnetic moments. The Cr local structure resolved by extended x-ray absorption fine structure (EXAFS) is also found to be affected by the alloy's composition. Both EXAFS and ab initio calculations show a change in the Cr local atomic structure above 10 at.% Cr content from the distance contraction of the first two coordination shells around the Cr absorbing atom. These results indicate the strong dependence of magnetic and structural properties of these alloys on Cr concentration.

[Retroperitoneal haematoma seen on CT scan in 2 patients with abdominal symptoms, aneurysm of the abdominal aorta and normal haemodynamics]. / Retroperitoneaal hematoom op CT bij 2 patiënten met buikklachten, een aneurysma van de aorta abdominalis en normale hemodynamiek.

In 2 patients, men aged 73 and 66 undergoing physical and ultrasound examinations for complaints of abdominal pain, an aneurysm of the abdominal aorta (AAA) with a diameter of 7-8 cm was discovered. Both their blood pressure and heart rate were normal. The older man then underwent a CT scan as did the younger man after being observed overnight. They both proved to have a ruptured AAA. They were operated on and recovered well. It can be problematic to diagnose a ruptured AAA quickly in patients with abdominal and back pain, AAA on ultrasound and normal haemodynamic parameters. In this situation an emergency CT scan will visualize any retroperitoneal haematoma and the patient can undergo an emergency operation. If the CT scan does not show any rupture there is time for preoperative preparations before performing a semi-elective procedure.

Novel isotope effects observed in polarization echo experiments in glasses.

In recent years unexpected magnetic field effects have been observed in dielectric measurements on insulating glasses at very low temperatures. Polarization echo experiments have indicated that atomic tunneling systems are responsible for these effects and that the nuclear properties of the tunneling particles are of importance. Subsequently, it was suggested that the magnetic field effects are caused by tunneling systems carrying a nuclear quadrupole moment. Now we have studied the isotope effect in echo experiments on fully deuterated and ordinary glycerol clearly showing the crucial role of the nuclear quadrupole moments for the magnetic field effects. In addition, we have observed a new effect in the decay of spontaneous echoes in zero magnetic field for the deuterated samples which can be explained in terms of a quantum beating involving the quadrupole levels.

Psychoactive substance use and the risk of motor vehicle accidents.

The driving performance is easily impaired as a consequence of the use of alcohol and/or licit and illicit drugs. However, the role of drugs other than alcohol in motor vehicle accidents has not been well established. The objective of this study was to estimate the association between psychoactive drug use and motor vehicle accidents requiring hospitalisation. A prospective observational case-control study was conducted in the Tilburg region of The Netherlands from May 2000 to August 2001. Cases were car or van drivers involved in road crashes needing hospitalisation. Demographic and trauma related data was collected from hospital and ambulance records. Urine and/or blood samples were collected on admission. Controls were drivers recruited at random while driving on public roads. Sampling was conducted by researchers, in close collaboration with the Tilburg police, covering different days of the week and times of the day. Respondents were interviewed and asked for a urine sample. If no urine sample could be collected, a blood sample was requested. All blood and urine samples were tested for alcohol and a number of licit and illicit drugs. The main outcome measures were odds ratios (OR) for injury crash associated with single or multiple use of several drugs by drivers. The risk for road trauma was increased for single use of benzodiazepines (adjusted OR 5.1 (95% Cl: 1.8-14.0)) and alcohol (blood alcohol concentrations of 0.50-0.79 g/l, adjusted OR 5.5 (95% Cl: 1.3-23.2) and >or=0.8 g/l, adjusted OR 15.5 (95% Cl: 7.1-33.9)). High relative risks were estimated for drivers using combinations of drugs (adjusted OR 6.1 (95% Cl: 2.6-14.1)) and those using a combination of drugs and alcohol (OR 112.2 (95% Cl: 14.1-892)). Increased risks, although not statistically significantly, were assessed for drivers using amphetamines, cocaine, or opiates. No increased risk for road trauma was found for drivers exposed to cannabis. The study concludes that drug use, especially alcohol, benzodiazepines and multiple drug use and drug-alcohol combinations, among vehicle drivers increases the risk for a road trauma accident requiring hospitalisation.

Arm morbidity after complete axillary lymph node dissection for breast cancer.

The aim of the study was to clarify the factors causing and/or influence morbidity following axillary dissection in patients treated for breast cancer by either lumpectomy or mastectomy. The records of 106 women with invasive breast cancer treated between 1996 and 1997 were retrospectively reviewed. Objective assessment included measurement of lymphoedema, shoulder mobility and axillary sensation. A questionnaire was used for subjective assessment of arm morbidity and pain. Lymphoedema was present in 13% of patients, a restriction in shoulder function in 24%, while 93% of patients had an impaired sensation in the axillary region. Lymphoedema and restriction in shoulder function were common in patients after adjuvant axillary radiation. Morbidity following axillary lymph node dissection is high and confirms the potentially severe effects of a staging procedure on a relatively young population. Adjuvant radiotherapy increases morbidity significantly and therefore indications for adjuvant axillary radiotherapy should be revised with scrutiny for each patient individually, bearing in mind the disastrous consequences of the combination of radiotherapy and surgery on the axilla.

Phase fluctuations and the pseudogap in YBa(2)Cu(3)O (x).

The thermodynamics of the superconducting transition is studied as a function of doping using high-resolution expansivity data of YBa(2)Cu(3)O (x) single crystals and Monte Carlo simulations of the anisotropic 3D- XY model. We directly show that T(c) of underdoped YBa(2)Cu(3)O (x) is strongly suppressed from its mean-field value (T(MF)(c)) by phase fluctuations of the superconducting order parameter. For overdoped YBa(2)Cu(3)O (x) fluctuation effects are greatly reduced and T(c) approximately T(MF)(c). We find that T(MF)(c) exhibits a similar doping dependence as the pseudogap energy, naturally suggesting that the pseudogap arises from phase-incoherent Cooper pairing.

Anomalously large oxygen-ordering contribution to the thermal expansion of untwinned YBa2Cu3O6.95 single crystals: A glasslike transition near room temperature

We present high-resolution thermal expansion data from 5-500 K of untwinned YBa2Cu3Ox (Y123) single crystals for x approximately 6.95 and x = 7.0. Large contributions to the thermal expansivities due to O ordering are found for x approximately 6.95, which disappear below a kinetic glasslike transition near 280 K. The kinetics at this glass transition is governed by an energy barrier of 0.98+/-0.07 eV, in very good agreement with other O-ordering studies. Using thermodynamic arguments, we show that O ordering in the Y123 system is particularly sensitive to uniaxial stress along the chain axis and that the lack of well-ordered chains in Nd123 and La123 is most likely a consequence of a chemical-pressure effect.

Induction of micronuclei in haemocytes and gill cells of zebra mussels, Dreissena polymorpha, exposed to clastogens.

Zebra mussels, Dreissena polymorpha, were exposed to four directly acting reference clastogens (mitomycin C, bleomycin, dimethylarsinic acid and potassium chromate) under laboratory conditions. The aim was to examine the inducibility of micronuclei (MN) in haemocytes and gill cells. Positive responses were observed in both tissues for all four substances used under the given test conditions. The mean MN frequencies in treated mussels ranged between 3.2 and 6.9/1000 in haemocytes and between 5.4 and 6.7/1000 in gill cells. The spontaneous MN levels averaged 1.2 and 2.8/1000 in haemocytes and gill cells, respectively. The MN induction capacity of the different chemicals was equivalent in both tissues, except for the treatment with dimethylarsinic acid which generated a significantly higher MN rate in gill cells than in haemocytes. Several characteristics suggest that haemolymph is the more appropriate test tissue for environmental genotoxicity assessment: (1) a shorter preparation time of slides, (2) a more accurate identification of unambiguous MN, (3) a lower baseline MN frequency and a higher induction factor.