Home on the Range: Factors Explaining Partial Migration of African Buffalo in a Tropical Environment

Partial migration (when only some individuals in a population undertake seasonal migrations) is common in many species and geographical contexts. Despite the development of modern statistical methods for analyzing partial migration, there have been no studies on what influences partial migration in tropical environments. We present research on factors affecting partial migration in African buffalo (Syncerus caffer) in northeastern Namibia. Our dataset is derived from 32 satellite tracking collars, spans 4 years and contains over 35,000 locations. We used remotely sensed data to quantify various factors that buffalo experience in the dry season when making decisions on whether and how far to migrate, including potential man-made and natural barriers, as well as spatial and temporal heterogeneity in environmental conditions. Using an information-theoretic, non-linear regression approach, our analyses showed that buffalo in this area can be divided into 4 migratory classes: migrants, non-migrants, dispersers, and a new class that we call “expanders”. Multimodel inference from least-squares regressions of wet season movements showed that environmental conditions (rainfall, fires, woodland cover, vegetation biomass), distance to the nearest barrier (river, fence, cultivated area) and social factors (age, size of herd at capture) were all important in explaining variation in migratory behaviour. The relative contributions of these variables to partial migration have not previously been assessed for ungulates in the tropics. Understanding the factors driving migratory decisions of wildlife will lead to better-informed conservation and land-use decisions in this area

Emerging antimicrobial resistance in early and late-onset neonatal sepsis

Abstract Background Compared to developed countries, the use of antimicrobials in Egypt is less regulated and is available over the counter without the need for prescriptions. The impact of such policy on antimicrobial resistance has not been studied. This study aimed to determine the prevalence of early and late onset sepsis, and the frequency of antimicrobial resistance in a major referral neonatal intensive care unit (NICU). Methods The study included all neonates admitted to the NICU over a 12-month period. Prospectively collected clinical and laboratory data were retrieved, including blood cultures and endotracheal aspirate cultures if performed. Results A total of 953 neonates were admitted, of them 314 neonates were diagnosed with sepsis; 123 with early onset sepsis (EOS) and 191 with late onset sepsis (LOS). A total of 388 blood cultures were obtained, with 166 positive results. Total endotracheal aspirate samples were 127; of them 79 were culture-positive. The most frequently isolated organisms in blood were Klebsiella pneumoniae (42%) and Coagulase negative staphylococcus (19%) whereas in endotracheal cultures were Klebsiella pneumoniae (41%) and Pseudomonas aeruginosa (19%). Gram negative organisms were most resistant to ampicillins (100%), cephalosporins (93%–100%) and piperacillin-tazobactam (99%) with less resistance to aminoglycosides (36%–52%). Gram positive isolates were least resistant to vancomycin (18%). Multidrug resistance was detected in 92 (38%) cultures, mainly among gram negative isolates (78/92). Conclusions Antibiotic resistance constitutes a challenge to the management of neonatal sepsis in Egypt. Resistance was predominant in both early and late onset sepsis. This study supports the need to implement policies that prohibits the non-prescription community use of antibiotics

Sleep-Wake Cycle in Young and Older Persons with a Lifetime History of Mood Disorders

Considering the marked changes in sleep and circadian rhythms across the lifespan, age may contribute to the heterogeneity in sleep-wake profiles linked to mood disorders. This study aimed to investigate the contributions of age and depression severity to sleep-wake disturbances. The Hamilton Depression Rating Scale (HDRS) was administered to assess current symptoms severity in 238 persons with a history of a mood disorder between 12 and 90 years of age (y.o.). Actigraphy was recorded over five to 22 days. Regression analyses and analyses of variance [age (12–19 y.o., 20–39 y.o., 40–59 y.o., and ≥60 y.o.) by depression severity (HDRS< and ≥8)] were conducted. The 12–19 y.o. and 20–39 y.o. groups had a delayed sleep schedule and acrophase compared to all other groups. The ≥60 y.o. group had a lower rhythmicity and amplitude (p≤.006) than the 12–19 y.o. group (p≤.046). Participants with a HDRS≥8 spent longer time in bed, had later sleep offset times and had lower circadian rhythmicity than those with a HDRS<8 (p≤.036). Younger age and higher HDRS score correlated with later sleep onset and offset times, longer time in bed, higher WASO, lower sleep efficiency and later acrophase (p≤.023). Age was a significant predictor of delayed sleep and activity schedules (p≤.001). The profile of sleep-wake cycle disturbances associated with mood disorders changes with age, with prominent sleep phase delay during youth and reduced circadian strength in older persons. Conversely, disruptions in sleep consolidation seem more stable across age