A perspective on cortical layering and layer-spanning neuronal elements

This review article addresses the function of the layers of the cerebral cortex. We develop the perspective that cortical layering needs to be understood in terms of its functional anatomy, i.e., the terminations of synaptic inputs on distinct cellular compartments and their effect on cortical activity. The cortex is a hierarchical structure in which feed forward and feedback pathways have a layer-specific termination pattern. We take the view that the influence of synaptic inputs arriving at different cortical layers can only be understood in terms of their complex interaction with cellular biophysics and the subsequent computation that occurs at the cellular level. We use high-resolution fMRI, which can resolve activity across layers, as a case study for implementing this approach by describing how cognitive events arising from the laminar distribution of inputs can be interpreted by taking into account the properties of neurons that span different layers. This perspective is based on recent advances in measuring subcellular activity in distinct feed-forward and feedback axons and in dendrites as they span across layers

The Effects of Socio-Cultural Factors on the Performance of Women Small and Medium Enterprises in Tanzania

Globally, Small and Medium Enterprises (SMEs) play a great role in employment creation, income generation and economic growth. However, in Tanzania women SMEs are faced with a number of factors including socio-cultural factors (SCFs) which hinder their entrepreneurial development. This paper assesses the effects of SCFs on the performance of women SMEs. The study was conducted in Dodoma urban and Chamwino districts in Dodoma region employing cross-sectional and case study research designs in which 80 women SMEs were surveyed using questionnaires. Data were analyzed using descriptive statistics and binary logistic model. Findings show that women immobility, poor support from society members and ethnicity affect negatively the performance of women SMEs. Conversely, family roles, level of education and role models were important factors in nurturing the performance of women SMEs. The study generally concludes that SCFs have negative effect on the performance of women SMEs. This implies that, women SMEs stressed under such SCFs cannot perform outstandingly. We recommend that the government should formulate policies that encourage women participation in entrepreneurial activities. Key Words: Women SMEs, Socio-Cultural Factors, Performance, Tanzani

Modern Applications of Novel Electroless Plating Techniques

This dissertation is composed of three distinct but closely related topics on the electrochemical metallization of substrates. The first topic solves the longstanding problem of galvanic corrosion in connection with exploiting the advantageous properties of magnesium {Mg} alloys and is of vital interest to the automotive and aerospace sectors. The second topic provides a new approach to the selective electroless metallization of silicon {Si} in connection with solar cells and other electronic devices. The third topic details a novel method of metal thin film formation using wet chemistry techniques which allow for the deposition of alternating metal layers of different and similar nobility from a single electrolyte. Future possible avenues of investigation are suggested for each of the three topics. The resolution of the galvanic corrosion issue, as presented within herein, is based on the direct electroless deposition of metal thin films less active than the Mg alloy substrates. Claddings of copper {Cu}, nickel boron {Ni-B}, and phosphorous {P} alloys including: nickel {Ni-P}, cobalt {Co-P}, nickel-zinc Ni-Zn-P}, and other ternary alloys, were successfully deposited directly on Mg alloy surfaces. The electroless coating of Mg alloys was accomplished using minimal pre-treatments and made use of the naturally active properties of Mg-based substrates. Qualitative measures of the corrosion resistance of Ni-Zn-P coatings on Mg alloys demonstrated superior resistance to galvanic corrosion compared to uncoated surfaces. The selective electroless metallization of Si is accomplished with the selective removal of the silicon oxide {SiO x } by means of mechanical scribing thereby exposing Si. The exposure of Si provides a catalytic surface for the electroless deposition of gold {Au}, and silver {Ag}, and other metals. The mechanical scribing provides an inexpensive avenue for the selective metallization of Si for solar cells. The novel method of depositing alternating metal layers of both different and similar nobility is achieved by combining electroplating and electroless deposition within a single electrolyte. The technique, termed here hybrid electro-electroless deposition (HEED), provides coatings previously unobtainable using wet electrochemical techniques. The application of HEED is of interest for the provision of sacrificial coatings on Mg alloys for corrosion protection within the transportation sector

SmallSat Precision Navigation with Low-Cost MEMS IMU Swarms

The continued advancement of small satellite-based science missions requires the solution to a number of important technical challenges. Of particular note is that small satellite missions are characterized by tight constraints on cost, mass, power, and volume that make them unable to fly the high-quality Inertial Measurement Units (IMUs) required for orbital missions demanding precise orientation and positioning. Instead, small satellite missions typically fly low-cost Micro-Electro-Mechanical System (MEMS) IMUs. Unfortunately, the performance characteristics of these MEMS IMUs make them ineffectual in many spaceflight applications when employed in a single IMU system configuration

CALCULATION OF EMISSIONS FROM TRANSPORT SERVICES AND THEIR USE FOR THE INTERNALISATION OF EXTERNAL COSTS IN ROAD TRANSPORT

Impact of transport operations on the environment is an important criterion of quality services. Requirements for environmental acceptability has recently escalated, manufacturing and trading companies require the carriers to declare the impact of their activities on the environment. Area of concern are the emission factors used for calculating emissions and their unification. For this reason it was accepted norm STN EN 16258, which deals with the methodology of calculation and declaration of energy consumption and greenhouse gas emissions from transport services. Existing emission calculators do not allow the calculation of the external costs of transport services in the area of transport services impacts on the environment. Article deals with the design and application of the calculator of external costs of transport services as an extension, respectively another important function, emission calculator for field of transport services

Restricted cross-scale habitat selection by American beavers

Animal habitat selection, among other ecological phenomena, is spatially scale dependent. Habitat selection by American beavers Castor canadensis (hereafter, beaver) has been studied at singular spatial scales, but to date no research addresses multi-scale selection. Our objectives were to determine if beaver habitat selection was specialized to semiaquatic habitats and if variables explaining habitat selection are consistent between landscape and fine spatial scales. We built maximum entropy (MaxEnt) models to relate landscape-scale presence-only data to landscape variables, and used generalized linearmixed models to evaluate fine spatial scale habitat selection using global positioning system (GPS) relocation data. Explanatory variables between the landscape and fine spatial scale were compared for consistency. Our findings suggested that beaver habitat selection at coarse (study area) and fine (within home range) scales was congruent, and was influenced by increasing amounts of woody wetland edge density and shrub edge density, and decreasing amounts of open water edge density. Habitat suitability at the landscape scale also increased with decreasing amounts of grass frequency. As territorial, central-place foragers, beavers likely trade-off open water edge density (i.e., smaller non-forested wetlands or lodges closer to banks) for defense and shorter distances to forage and obtain construction material. Woody plants along edges and expanses of open water for predator avoidance may limit beaver fitness and subsequently determine beaver habitat selection

Surveillance of artemether-lumefantrine associated Plasmodium falciparum multidrug resistance protein-1 gene polymorphisms in Tanzania.

BACKGROUND: Resistance to anti-malarials is a major public health problem worldwide. After deployment of artemisinin-based combination therapy (ACT) there have been reports of reduced sensitivity to ACT by malaria parasites in South-East Asia. In Tanzania, artemether-lumefantrine (ALu) is the recommended first-line drug in treatment of uncomplicated malaria. This study surveyed the distribution of the Plasmodium falciparum multidrug resistance protein-1 single nucleotide polymorphisms (SNPs) associated with increased parasite tolerance to ALu, in Tanzania. METHODS: A total of 687 Plasmodium falciparum positive dried blood spots on filter paper and rapid diagnostic test strips collected by finger pricks from patients attending health facilities in six regions of Tanzania mainland between June 2010 and August 2011 were used. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to detect Pfmdr1 SNPs N86Y, Y184F and D1246Y. RESULTS: There were variations in the distribution of Pfmdr1 polymorphisms among regions. Tanga region had exceptionally high prevalence of mutant alleles, while Mbeya had the highest prevalence of wild type alleles. The haplotype YFY was exclusively most prevalent in Tanga (29.6%) whereas the NYD haplotype was the most prevalent in all other regions. Excluding Tanga and Mbeya, four, most common Pfmdr1 haplotypes did not vary between the remaining four regions (χ² = 2.3, p = 0.512). The NFD haplotype was the second most prevalent haplotype in all regions, ranging from 17% - 26%. CONCLUSION: This is the first country-wide survey on Pfmdr1 mutations associated with ACT resistance. Distribution of individual Pfmdr1 mutations at codons 86, 184 and 1246 varies throughout Tanzanian regions. There is a general homogeneity in distribution of common Pfmdr1 haplotypes reflecting strict implementation of ALu policy in Tanzania with overall prevalence of NFD haplotype ranging from 17 to 26% among other haplotypes. With continuation of ALu as first-line drug this haplotype is expected to keep rising, thus there is need for continued pharmacovigilance studies to monitor any delayed parasite clearance by the drug

Desempeño reproductivo del bocachico Prochilodus magdalenae inducido dos veces en un mismo año

RESUMEN Objetivo. Evaluar el desempeño reproductivo del bocachico (Prochilodus magdalenae) sometido a dos inducciones hormonales con extracto pituitario de carpa (EPC) en un mismo año. Materiales y métodos. 23 hembras, en fase de maduración final, fueron inducidas con 5mg EPC/Kg de peso vivo, en dos aplicaciones, inicialmente 10% y doce horas después 90% restante. A los machos fue aplicado 80% de la dosis total de las hembras. Resultados. Después de la primera inducción hormonal, las hembras estuvieron aptas nuevamente a los 97.6±12.4 días. El índice de ovulación en ambas inducciones fue de 0.91 (21/23). La fecundidad absoluta (g-ovocitos/hembra) no presentó diferencias significativa entre la primera y segunda inducción (36.2 y 44.6 g-ovocitos/hembra, respectivamente) (p>0.05); pero cuando se expresó en número de ovocitos/hembra se observó diferencia significativa (p<0.05), siendo mayor en la primera inducción (53535 ovocitos/hembra) que en la segunda (40658 ovocitos/hembra). La fecundidad relativa, expresada tanto en g-ovocitos/Kg-hembra como ovocitos/Kg-hembra, mostraron diferencia significativa, siendo mayor en la primera inducción (p<0.05). La tasa de fecundación (73.9±19.6%) y eclosión (56.9±17.9%) fueron mayores en la primera inducción, comparadas con la segunda (55.6±21.1% y 35.6±20.7%, respectivamente) (p<0.05). Conclusiones. Después de una inducción hormonal se requiere de aproximadamente tres meses para que una hembra de bocachico alcance nuevamente la maduración final y esté apta para una nueva inducción hormonal. El índice de ovulación no fue afectado por una segunda inducción en un mismo año, pero la fecundidad absoluta y relativa puede disminuirse entre 24 y 66% y las tasas de fecundación y eclosión entre 23 y 36%

Self-reported side effects and adherence to antiretroviral therapy in HIV-infected pregnant women under option B+: a prospective study

BACKGROUND: Antiretroviral therapy (ART) regimens containing efavirenz (EFV) are recommended as part of universal ART for pregnant and breastfeeding women. EFV may have appreciable side effects (SE), and ART adherence in pregnancy is a major concern, but little is known about ART SE and associations with adherence in pregnancy. METHODS: We investigated the distribution of patient-reported SE (based on Division of AIDS categories) and the association of SE with missed ART doses in a cohort of 517 women starting EFV+3TC/FTC+TDF during pregnancy. In analysis, SE were considered in terms of their overall frequency, by systems category, and by latent classes. RESULTS: Overall 97% of women reported experiencing at least one SE after ART initiation, with 48% experiencing more than five SE. Gastrointestinal, central nervous system, systemic and skin SE were reported by 81%, 85%, 79% and 31% of women, respectively, with considerable overlap across groups. At least one missed dose was reported by 32% of women. In multivariable models, ART non-adherence was associated with systemic SE compared to other systems categories, and measures of the overall burden of SE experienced were most strongly associated with missed ART doses. CONCLUSION: These data demonstrate very high levels of SE in pregnant women initiating EFV-based ART and a strong association between SE burden and ART adherence. ART regimens with reduced SE profiles may enhance adherence, and as countries expand universal ART for all adult patients, counseling must include preparation for ART SE

Nanoscale imaging of He-ion irradiation effects on amorphous TaOx_x toward electroforming-free neuromorphic functions

Resistive switching in thin films has been widely studied in a broad range of materials. Yet the mechanisms behind electroresistive switching have been persistently difficult to decipher and control, in part due to their non-equilibrium nature. Here, we demonstrate new experimental approaches that can probe resistive switching phenomena, utilizing amorphous TaO$_x$ as a model material system. Specifically, we apply Scanning Microwave Impedance Microscopy (sMIM) and cathodoluminescence (CL) microscopy as direct probes of conductance and electronic structure, respectively. These methods provide direct evidence of the electronic state of TaO$_x$ despite its amorphous nature. For example CL identifies characteristic impurity levels in TaO$_x$, in agreement with first principles calculations. We applied these methods to investigate He-ion-beam irradiation as a path to activate conductivity of materials and enable electroforming-free control over resistive switching. However, we find that even though He-ions begin to modify the nature of bonds even at the lowest doses, the films conductive properties exhibit remarkable stability with large displacement damage and they are driven to metallic states only at the limit of structural decomposition. Finally, we show that electroforming in a nanoscale junction can be carried out with a dissipated power of < 20 nW, a much smaller value compared to earlier studies and one that minimizes irreversible structural modifications of the films. The multimodal approach described here provides a new framework toward the theory/experiment guided design and optimization of electroresistive materials