Primitive roles for inhibitory interneurons in developing frog spinal cord

Understanding the neuronal networks in the mammal spinal cord is hampered by the diversity of neurons and their connections. The simpler networks in developing lower vertebrates may offer insights into basic organization. To investigate the function of spinal inhibitory interneurons in Xenopus tadpoles, paired whole-cell recordings were used. We show directly that one class of interneuron, with distinctive anatomy, produces glycinergic, negative feedback inhibition that can limit firing in motoneurons and interneurons of the central pattern generator during swimming. These same neurons also produce inhibitory gating of sensory pathways during swimming. This discovery raises the possibility that some classes of interneuron, with distinct functions later in development, may differentiate from an earlier class in which these functions are shared. Preliminary evidence suggests that these inhibitory interneurons express the transcription factor engrailed, supporting a probable homology with interneurons in developing zebrafish that also express engrailed and have very similar anatomy and functions

Influence of AgNO3 on somatic embryo induction and development in Manchurian ash (Fraxinus mandshurica Rupr.)

In this present study, we explored the effects of silver nitrate (AgNO3) on somatic embryo induction and the development from immature zygotic embryos in Manchurian ash (Fraxinus mandshurica Rupr.). AgNO3 played a minor role on in vitro embryo induction frequency and in the number of somatic embryos per explant. However, 1 mg L–1 AgNO3 enhanced synchronization and significantly inhibited abnormal somatic embryo formation suggesting that AgNO3 might serve an important function in controlling the development of somatic embryos in Manchurian ash. Our results provided foundation for a future more efficient somatic embryogenesis and regeneration protocol.Key words: Abnormality, Fraxinus mandshurica, silver nitrate, somatic embryogenesis, synchronization

Knowledge, attitude and practice (KAP) of mental illness among staff in general medical facilities in Kenya: practice and policy implications

Objective: To determine the knowledge, attitudes and beliefs about mental illness among staff in general hospitals. Method: A descriptive cross-sectional study conducted on staff in ten medical facilities in Kenya on their socio-demographic characteristics, professional qualifications and knowledge, attitudes and practice (KAP) toward mental illness. Results: A total of 684 general hospital staff: nurses (47.8%); doctors (18.1%); registered clinical officers (5.1%); students (9.5%) and support staff (19.5%) were recruited. About three quarters were under 40 years of age; most thought mental illness could be managed in general hospital facilities; the older the doctors were (age 40 years and older) the more they were aware of and positive towards mental illness. Most of the workers did not suspect any psychiatric symptoms among the patients they treated resulting in low referral rates for psychiatric services. Conclusion: There are gaps in knowledge on mental illness which could be constructively filled with Continued Medical Education (CME).Key words: Hospital, General; Health Knowledge, Attitudes, Practice; Mental disorders; Keny

Traditional healers and provision of mental health services in cosmopolitan informal settlements in Nairobi, Kenya

Objective: The study aimed to investigate the types of mental illnesses treated by traditional healers, and their methods of identifying and treating mental illnesses in their patients. Method: In urban informal settlements of Kibera, Kangemi and Kawangware in Nairobi, Kenya, we used opportunistic sampling until the required number of traditional healers was reached, trying as much as possible to represent the different communities of Kenya. Focus group discussions were held with traditionalhealers in each site and later an in-depth interview was conducted with each traditional healer. An in-depth interview with each patient of the traditional healer was conducted and thereafter the MINIPLUS was administered to check the mental illness diagnoses arrived at or missed by the traditional healers. Quantitative analysis was performed using SPSS while focus group discussions and in-depth interviews were analysed for emerging themes.Results: Traditional healers are consulted for mental disorders by members of the community. They are able to recognize some mental disorders, particularly those relating to psychosis. However, they are limited especially for common mental disorders.Conclusion: There is a need to educate healers on how to recognize different types of mental disorders and make referrals when patients are not responding to their treatments.Keywords: Traditional Healers; Mental illness; Informal settlements; Keny

Eigenlogic: a Quantum View for Multiple-Valued and Fuzzy Systems

We propose a matrix model for two- and many-valued logic using families of observables in Hilbert space, the eigenvalues give the truth values of logical propositions where the atomic input proposition cases are represented by the respective eigenvectors. For binary logic using the truth values {0,1} logical observables are pairwise commuting projectors. For the truth values {+1,-1} the operator system is formally equivalent to that of a composite spin 1/2 system, the logical observables being isometries belonging to the Pauli group. Also in this approach fuzzy logic arises naturally when considering non-eigenvectors. The fuzzy membership function is obtained by the quantum mean value of the logical projector observable and turns out to be a probability measure in agreement with recent quantum cognition models. The analogy of many-valued logic with quantum angular momentum is then established. Logical observables for three-value logic are formulated as functions of the Lz observable of the orbital angular momentum l=1. The representative 3-valued 2-argument logical observables for the Min and Max connectives are explicitly obtained.Comment: 11 pages, 2 table

A Fast Algorithm for Robust Regression with Penalised Trimmed Squares

The presence of groups containing high leverage outliers makes linear regression a difficult problem due to the masking effect. The available high breakdown estimators based on Least Trimmed Squares often do not succeed in detecting masked high leverage outliers in finite samples. An alternative to the LTS estimator, called Penalised Trimmed Squares (PTS) estimator, was introduced by the authors in \cite{ZiouAv:05,ZiAvPi:07} and it appears to be less sensitive to the masking problem. This estimator is defined by a Quadratic Mixed Integer Programming (QMIP) problem, where in the objective function a penalty cost for each observation is included which serves as an upper bound on the residual error for any feasible regression line. Since the PTS does not require presetting the number of outliers to delete from the data set, it has better efficiency with respect to other estimators. However, due to the high computational complexity of the resulting QMIP problem, exact solutions for moderately large regression problems is infeasible. In this paper we further establish the theoretical properties of the PTS estimator, such as high breakdown and efficiency, and propose an approximate algorithm called Fast-PTS to compute the PTS estimator for large data sets efficiently. Extensive computational experiments on sets of benchmark instances with varying degrees of outlier contamination, indicate that the proposed algorithm performs well in identifying groups of high leverage outliers in reasonable computational time.Comment: 27 page

The prevalence of depressive symptoms among adolescents in Nairobi public secondary schools: association with perceived maladaptive parental behaviour

Objective: Depression in adolescents is a matter of concern because of its high prevalence, potential recurrence and impairment of functioning in the affected individual. The study sought to determine the prevalence of depressive symptoms among adolescents in Nairobi (Kenya) public secondary schools; make a comparison between day and boarding students; and identify associated factors in this population. Method: A random sample of school going adolescents was taken from a stratified sample of 17 secondary schools out of the 49 public secondary schools in Nairobi province. The sample was stratified to take into account geographical distribution, day and boarding schools, boys only, girls only and mixed (co-education) schools in the capital city of Kenya. Self administered instruments (EMBU and CDI) were used to measure perceived parental behaviour and levels of depression in a total of 1,276 students excluding those who had no living parent. Results: The prevalence of clinically significant depressive symptoms was 26.4%. The occurrence was higher in girls than it was in boys p<0.001. Students in boarding schools had more clinically significant depressive symptoms compared to day students (p=0.01). More girls exhibited suicidal  behaviour than boys (p<0.001). There was a significant correlation between depressive symptoms and suicidal behaviour (p<0.001). CDIscores correlated positively with age (p<0.001) with an increase in CDI  score with unit increase in age among students 14-17 years old, perceived rejecting maternal parenting behaviour (p<0.001), perceived no emotional attachment paternal behaviour (p<0.001), perceived no emotional attachment maternal behaviour (p<0.001), and perceived under protective paternal behaviour (p=0.005).Conclusion: Perceived maladaptive parental behaviours are substantially associated with the development of depressive symptoms and suicidal behaviour in children.Key words: Depression; Adolescent; Parent; Keny

A genetic contribution from the Far East into Ashkenazi Jews via the ancient Silk Road

Contemporary Jews retain a genetic imprint from their Near Eastern ancestry, but obtained substantial genetic components from their neighboring populations during their history. Whether they received any genetic contribution from the Far East remains unknown, but frequent communication with the Chinese has been observed since the Silk Road period. To address this issue, mitochondrial DNA (mtDNA) variation from 55,595 Eurasians are analyzed. The existence of some eastern Eurasian haplotypes in eastern Ashkenazi Jews supports an East Asian genetic contribution, likely from Chinese. Further evidence indicates that this connection can be attributed to a gene flow event that occurred less than 1.4 kilo-years ago (kya), which falls within the time frame of the Silk Road scenario and fits well with historical records and archaeological discoveries. This observed genetic contribution from Chinese to Ashkenazi Jews demonstrates that the historical exchange between Ashkenazim and the Far East was not confined to the cultural sphere but also extended to an exchange of genes

Picophytoplankton biomass distribution in the global ocean

The smallest marine phytoplankton, collectively termed picophytoplankton, have been routinely enumerated by flow cytometry since the late 1980s during cruises throughout most of the world ocean. We compiled a database of 40 946 data points, with separate abundance entries for Prochlorococcus, Synechococcus and picoeukaryotes. We use average conversion factors for each of the three groups to convert the abundance data to carbon biomass. After gridding with 1? spacing, the database covers 2.4% of the ocean surface area, with the best data coverage in the North Atlantic, the South Pacific and North Indian basins, and at least some data in all other basins. The average picophytoplankton biomass is 12 ± 22 µg Cl-1 or 1.9 g Cm-2. We estimate a total global picophytoplankton biomass of 0.53–1.32 Pg C (17–39% Prochlorococcus, 12–15% Synechococcus and 49–69% picoeukaryotes), with an intermediate/best estimate of 0.74 Pg C. Future efforts in this area of research should focus on reporting calibrated cell size and collecting data in undersampled regions