Tree size and fecundity influence ballistic seed dispersal of two dominant mast-fruiting species in a tropical rain forest

Seed production, seed dispersal, and seedling recruitment are integral to forest dynamics, especially in masting species. Often these are studied separately, yet scarcely ever for species with ballistic dispersal even though this mode of dispersal is common in legume trees of tropical African rain forests. Here, we studied two dominant main-canopy tree species, Microberlinia bisulcata and Tetraberlinia bifoliolata (Caesalpinioideae), in 25 ha of primary rain forest at Korup, Cameroon, during two successive masting events (2007/2010). In the vicinity of c. 100 and 130 trees of each species, 476/580 traps caught dispersed seeds and beneath their crowns c. 57,000 pod valves per species were inspected to estimate tree-level fecundity. Seed production of trees increased non-linearly and asymptotically with increasing stem diameters. It was unequal within the two species’ populations, and differed strongly between years to foster both spatial and temporal patchiness in seed rain. The M. bisulcata trees could begin seeding at 42–44 cm diameter: at a much larger size than could T. bifoliolata (25 cm). Nevertheless, per capita life-time reproductive capacity was c. five times greater in M. bisulcata than T. bifoliolata owing to former’s larger adult stature, lower mortality rate (despite a shorter life-time) and smaller seed mass. The two species displayed strong differences in their dispersal capabilities. Inverse modelling (IM) revealed that dispersal of M. bisulcata was best described by a lognormal kernel. Most seeds landed at 10–15 m from stems, with 1% of them going beyond 80 m (<100 m). The direct estimates of fecundity significantly improved the models fitted. The lognormal also described well the seedling recruitment distribution of this species in 121 ground plots. By contrast, the lower intensity of masting and more limited dispersal of the heavier-seeded T. bifoliolata prevented reliable IM. For this species, seed density as function of distance to traps suggested a maximum dispersal distance of 40–50 m, and a correspondingly more aggregated seedling recruitment pattern ensued than for M. bisulcata. From this integrated field study, we conclude that the reproductive traits of M. bisulcata give it a considerable advantage over T. bifoliolata by better dispersing more seeds per capita to reach more suitable establishment sites, and combined with other key traits they explain its local dominance in the forest. Understanding the linkages between size at onset of maturity, individual fecundity, and dispersal capability can better inform the life-history strategies, and hence management, of co-occurring tree species in tropical forests.

Nutritional risk is a clinical predictor of postoperative mortality and morbidity in surgery for colorectal cancer

This study investigated whether nutritional risk scores applied at hospital admission predict mortality and complications after colorectal cancer surgery.

Early mortality and loss to follow-up in HIV-infected children starting antiretroviral therapy in Southern Africa

Many HIV-infected children in Southern Africa have been started on antiretroviral therapy (ART), but loss to follow up (LTFU) can be substantial. We analyzed mortality in children retained in care and in all children starting ART, taking LTFU into account.

Mortality and safety of catheter ablation for antiarrhythmic drug-refractory ventricular tachycardia in elderly patients with coronary artery disease

As the population ages, recurrent ventricular tachycardia (VT) is increasingly encountered in elderly patients with ischemic heart disease. Radiofrequency catheter ablation is useful for reducing VT therapy in patients with an implantable defibrillator. The utility of radiofrequency catheter ablation in the elderly is not well defined.

Excitability and recruitment patterns of spinal motoneurons in human sleep as assessed by F-wave recordings

This study examines the excitability and recruitment of spinal motoneurons in human sleep. The main objective was to assess whether supraspinal inhibition affects the different subpopulations of the compound spinal motoneuron pool in the same way or rather in a selective fashion in the various sleep stages. To this end, we studied F-conduction velocities (FCV) and F-tacheodispersion alongside F-amplitudes and F-persistence in 22 healthy subjects in sleep stages N2, N3 (slow-wave sleep), REM and in wakefulness. Stimuli were delivered on the ulnar nerve, and F-waves were recorded from the first dorsal interosseus muscle. Repeated sets of stimuli were stored to obtain at least 15 F-waves for each state of vigilance. F-tacheodispersion was calculated based on FCVs using the modified Kimura formula. Confirming the only previous study, excitability of spinal motoneurons was generally decreased in all sleep stages compared with wakefulness as indicated by significantly reduced F-persistence and F-amplitudes. More importantly, F-tacheodispersion showed a narrowed range of FCV in all sleep stages, most prominently in REM. In non-REM, this narrowed range was associated with a shift towards significantly decreased maximal FCV and mean FCV as well as with a trend towards lower minimal FCV. In REM, the lowering of mean FCV was even more pronounced, but contrary to non-REM sleep without a shift of minimal and maximal FCV. Variations in F-tacheodispersion between sleep stages suggest that different supraspinal inhibitory neuronal circuits acting on the spinal motoneuron pool may contribute to muscle hypotonia in human non-REM sleep and to atonia in REM sleep.

Mortality and neurologic injury after surgical repair with hypothermic circulatory arrest in acute and chronic proximal thoracic aortic pathology: effect of age on outcome

The goal of this study was to determine whether advanced age affects mortality and incidence of neurological injury in patients undergoing surgical repair with hypothermic circulatory arrest in acute and chronic thoracic aortic pathology.

Mortality and morbidity in the city of Bern, Switzerland, 1805-1815 with special emphasis on infant, child and maternal deaths

This article contributes to the research on demographics and public health of urban populations of preindustrial Europe. The key source is a burial register that contains information on the deceased, such as age and sex, residence and cause of death. This register is one of the earliest compilations of data sets of individuals with this high degree of completeness and consistency. Critical assessment of the register's origin, formation and upkeep promises high validity and reliability. Between 1805 and 1815, 4,390 deceased inhabitants were registered. Information concerning these individuals provides the basis for this study. Life tables of Bern's population were created using different models. The causes of death were classified and their frequency calculated. Furthermore, the susceptibility of age groups to certain causes of death was established. Special attention was given to causes of death and mortality of newborns, infants and birth-giving women. In comparison to other cities and regions in Central Europe, Bern's mortality structure shows low rates for infants (q0=0.144) and children (q1-4=0.068). This could have simply indicated better living conditions. Life expectancy at birth was 43 years. Mortality was high in winter and spring, and decreased in summer to a low level with a short rise in August. The study of the causes of death was inhibited by difficulties in translating early 19th century nomenclature into the modern medical system. Nonetheless, death from metabolic disorders, illnesses of the respiratory system, and debilitation were the most prominent causes in Bern. Apparently, the worst killer of infants up to 12 months was the "gichteren", an obsolete German term for lethal spasmodic convulsions. The exact modern identification of this disease remains unclear. Possibilities such as infant tetanus or infant epilepsy are discussed. The maternal death rate of 0.72% is comparable with values calculated from contemporaneous sources. Relevance of childbed fever in the early 1800s was low. Bern's data indicate that the extent of deaths related to childbirth in this period is overrated. This research has an explicit interdisciplinary value for various fields including both the humanities and natural sciences, since information reported here represents the complete age and sex structure of a deceased population. Physical anthropologists can use these data as a true reference group for their palaeodemographic studies of preindustrial Central Europe of the late 18th and early 19th century. It is a call to both historians and anthropologists to use our resources to a better effect through combination of methods and exchange of knowledge.

Mortality and loss to follow-up in the first year of ART: Malawi national ART programme

To analyse mortality, loss to follow-up (LTFU) and retention on antiretroviral treatment (ART) in the first year of ART across all age groups in the Malawi national ART programme.

Evaluation of multidimensional geriatric assessment as a predictor of mortality and cardiovascular events after transcatheter aortic valve implantation

This study evaluated Multidimensional Geriatric Assessment (MGA) as predictor of mortality and major adverse cardiovascular and cerebral events (MACCE) after transcatheter aortic valve implantation (TAVI).

Decreasing mortality and changing patterns of causes of death in the Swiss HIV Cohort Study

Mortality among HIV-infected persons is decreasing, and causes of death are changing. Classification of deaths is hampered because of low autopsy rates, frequent deaths outside of hospitals, and shortcomings of International Statistical Classification of Diseases and Related Health Problems (ICD-10) coding.

Doxycycline reduces mortality and injury to the brain and cochlea in experimental pneumococcal meningitis

Bacterial meningitis is characterized by an inflammatory reaction to the invading pathogens that can ultimately lead to sensorineural hearing loss, permanent brain injury, or death. The matrix metalloproteinases (MMPs) and tumor necrosis factor alpha-converting enzyme (TACE) are key mediators that promote inflammation, blood-brain barrier disruption, and brain injury in bacterial meningitis. Doxycycline is a clinically used antibiotic with anti-inflammatory effects that lead to reduced cytokine release and the inhibition of MMPs. Here, doxycycline inhibited TACE with a 50% inhibitory dose of 74 microM in vitro and reduced the amount of tumor necrosis factor alpha released into the cerebrospinal fluid by 90% in vivo. In an infant rat model of pneumococcal meningitis, a single dose of doxycycline (30 mg/kg) given as adjuvant therapy in addition to ceftriaxone 18 h after infection significantly reduced the mortality, the blood-brain barrier disruption, and the extent of cortical brain injury. Adjuvant doxycycline (30 mg/kg given subcutaneously once daily for 4 days) also attenuated hearing loss, as assessed by auditory brainstem response audiometry, and neuronal death in the cochlear spiral ganglion at 3 weeks after infection. Thus, doxycycline, probably as a result of its anti-inflammatory properties, had broad beneficial effects in the brain and the cochlea and improved survival in this model of pneumococcal meningitis in infant rats.