LABOR PRODUCTIVITY WITHIN THE AFRICAN AGRICULTURAL HOUSEHOLD: THE HOUSEHOLD PRODUCTION MODEL REVISITED

The benchmark concept is used to understand changes in farm household response to development dynamics. 1996-97 cropping seasons data from Cameroon is used to develop and test a "separate spheres" household model. Labor productivity for men and women is discussed, along with their implications for research and resource management policies.agriculture, labor productivity, gender, production, consumption, Consumer/Household Economics, Labor and Human Capital,

Absence of a chromatic linear motion mechanism in human vision

AbstractWe have investigated motion mechanisms in central and perifoveal vision using two-frame random Gabor kinematograms with isoluminant red-green or luminance stimuli. In keeping with previous results, we find that performance dominated by a linear motion mechanism is obtained using high densities of micropatterns and small temporal intervals between frames, while nonlinear performance is found with low densities and longer temporal intervals [Boulton, J. C., & Baker, C. L. (1994) Proceedings of SPIE, computational vision based on neurobiology, 2054, 124–133]. We compare direction discrimination and detection thresholds in the presence of variable luminance and chromatic noise. Our results show that the linear motion response obtained from chromatic stimuli is selectively masked by luminance noise; the effect is selective for motion since luminance noise masks direction discrimination thresholds but not stimulus detection. Furthermore, we find that chromatic noise has the reverse effect to luminance noise: detection thresholds for the linear chromatic stimulus are masked by chromatic noise but direction discrimination is relatively unaffected. We thus reveal a linear ‘chromatic’ mechanism that is susceptible to luminance noise but relatively unaffected by color noise. The nonlinear chromatic mechanism behaves differently since both detection and direction discrimination are unaffected by luminance noise but masked by chromatic noise. The double dissociation between the effects of chromatic and luminance noise on linear and nonlinear motion mechanisms is not based on stimulus speed or differences in the temporal presentations of the stimuli. We conclude that: (1) ‘chromatic’ linear motion is solely based on a luminance signal, probably arising from cone-based temporal phase shifts; (2) the nonlinear chromatic motion mechanism is purely chromatic; and (3) we find the same results for both perifoveal and foveal presentations

Phase-dependent interactions in visual cortex to combinations of first- and second-order stimuli

A fundamental task of the visual system is to extract figure-ground boundaries between objects, which are often defined not only by differences in luminance but also by "second order" contrast or texture differences. Responses of cortical neurons to both first- and second order patterns have been previously studied extensively, but only for responses to either type of stimulus in isolation. Here we examined responses of visual cortex neurons to the spatial relationship between superimposed periodic luminance modulation (LM) and contrast modulation (CM) stimuli, whose contrasts were adjusted to give equated responses when presented alone. Extracellular single unit recordings were made in area 18 of the cat, whose neurons show very similar responses to CM and LM stimuli as those in primate area V2 (Li et al, 2014). Most neurons showed a significant dependence on the relative phase of the combined LM and CM patterns, with a clear overall optimal response when they were approximately phase-aligned. The degree of this phase preference, and the contributions of suppressive and/or facilitatory interactions, varied considerably from one neuron to another. Such phase-dependent and phase-invariant responses were evident in both simple- and complex-type cells. These results place important constraints on any future model of the underlying neural circuitry for second-order responses. The diversity in the degree of phase dependence between LM and CM stimuli that we observe could help disambiguate different kinds of boundaries in natural scenes

The Future Role of Strategic Landpower

Recent Russian aggression in Ukraine has reenergized military strategists and senior leaders to evaluate the role of strategic Landpower. American leadership in the European theater has mobilized allies and partners to reconsider force postures for responding to possible aggression against NATO members. Although Russian revisionist activity remains a threat in Europe, the challenges in the Pacific for strategic Landpower must also be considered. At the same time, the homeland, the Arctic, climate change, and the results of new and emerging technology also challenge the application of strategic Landpower. This publication serves as part of an enduring effort to evaluate strategic Landpower’s role, authorities, and resources for accomplishing the national strategic goals the Joint Force may face in the next conflict. This study considers multinational partners, allies, and senior leaders that can contribute to overcoming these enduring challenges. The insights derived from this study, which can be applied to both the European and Indo-Pacific theaters, should help leaders to consider these challenges, which may last a generation. Deterrence demands credible strategic response options integrated across warfighting functions. This valuable edition will continue the dialogue about addressing these issues as well as other emerging ones.https://press.armywarcollege.edu/monographs/1959/thumbnail.jp

Identification of folate receptor α (FRα) binding oligopeptides and their evaluation for targeted virotherapy applications

Oncolytic virotherapies (OV) based on human adenoviral (HAdV) vectors hold significant promise for the treatment of advanced ovarian cancers where local, intraperitoneal delivery to tumour metastases is feasible, bypassing many complexities associated with intravascular delivery. The efficacy of HAdV-C5-based OV is hampered by a lack of tumour selectivity, where the primary receptor, hCAR, is commonly downregulated during malignant transformation. Conversely, folate receptor alpha (FRα) is highly expressed on ovarian cancer cells, providing a compelling target for tumour selective delivery of virotherapies. Here, we identify high-affinity FRα-binding oligopeptides for genetic incorporation into HAdV-C5 vectors. Biopanning identified a 12-mer linear peptide, DWSSWVYRDPQT, and two 7-mer cysteine-constrained peptides, CIGNSNTLC and CTVRTSAEC that bound FRα in the context of the phage particle. Synthesised lead peptide, CTVRTSAEC, bound specifically to FRα and could be competitively inhibited with folic acid. To assess the capacity of the elucidated FRα-binding oligopeptides to target OV to FRα, we genetically incorporated the peptides into the HAdV-C5 fiber-knob HI loop including in vectors genetically ablated for hCAR interactions. Unfortunately, the recombinant vectors failed to efficiently target transduction via FRα due to defective intracellular trafficking following entry via FRα, indicating that whilst the peptides identified may have potential for applications for targeted drug delivery, they require additional refinement for targeted virotherapy applications

Assessing Local Health Department Performance in Diabetes Prevention and Control — North Carolina, 2005

Introduction: To improve the public health system's ability to prevent and control chronic diseases, we must first understand current practice and develop appropriate strategies for measuring performance. The objectives of this study were to measure capacity and performance of local health departments in diabetes prevention and control and to investigate characteristics associated with performance. Methods: In 2005, we conducted a cross-sectional mailed survey of all 85 North Carolina local health departments to assess capacity and performance in diabetes prevention and control based on the 10 Essential Public Health Services and adapted from the Local Public Health System Performance Assessment Instrument. We linked survey responses to county-level data, including data from a national survey of local health departments. Results: Local health departments reported a median of 0.05 full-time equivalent employees in diabetes prevention and 0.1 in control. Performance varied across the 10 Essential Services; activities most commonly reported included providing information to the public and to policy makers (76%), providing diabetes education (58%), and screening (74%). The mean score on a 10-point performance index was 3.5. Characteristics associated with performance were population size, health department size and accreditation status, and diabetes-specific external funding. Performance was not better in localities where the prevalence of diabetes was high or availability of primary care was low. Conclusion: Most North Carolina local health departments had limited capacity to conduct diabetes prevention or control programs in their communities. Diabetes is a major cause of illness and death, yet it is neglected in public health practice. These findings suggest opportunities to enhance local public health practice, particularly through targeted funding and technical assistance

Dynamical chiral symmetry breaking and confinement with an infrared-vanishing gluon propagator?

We study a model Dyson-Schwinger equation for the quark propagator closed using an {\it Ansatz} for the gluon propagator of the form \mbox{$D(q) \sim q^2/[(q^2)^2 + b^4]$} and two {\it Ans\"{a}tze} for the quark-gluon vertex: the minimal Ball-Chiu and the modified form suggested by Curtis and Pennington. Using the quark condensate as an order parameter, we find that there is a critical value of $b=b_c$ such that the model does not support dynamical chiral symmetry breaking for $b>b_c$. We discuss and apply a confinement test which suggests that, for all values of $b$, the quark propagator in the model {\bf is not} confining. Together these results suggest that this Ansatz for the gluon propagator is inadequate as a model since it does not yield the expected behaviour of QCD.Comment: 21 Pages including 4 PostScript figures uuencoded at the end of the file. Replacement: slight changes of wording and emphasis. ADP-93-215/T133, ANL-PHY-7599-TH-93, FSU-SCRI-93-108, REVTEX 3.

Fructose transport-deficient Staphylococcus aureus reveals important role of epithelial glucose transporters in limiting sugar-driven bacterial growth in airway surface liquid.

Hyperglycaemia as a result of diabetes mellitus or acute illness is associated with increased susceptibility to respiratory infection with Staphylococcus aureus. Hyperglycaemia increases the concentration of glucose in airway surface liquid (ASL) and promotes the growth of S. aureus in vitro and in vivo. Whether elevation of other sugars in the blood, such as fructose, also results in increased concentrations in ASL is unknown and whether sugars in ASL are directly utilised by S. aureus for growth has not been investigated. We obtained mutant S. aureus JE2 strains with transposon disrupted sugar transport genes. NE768(fruA) exhibited restricted growth in 10 mM fructose. In H441 airway epithelial-bacterial co-culture, elevation of basolateral sugar concentration (5-20 mM) increased the apical growth of JE2. However, sugar-induced growth of NE768(fruA) was significantly less when basolateral fructose rather than glucose was elevated. This is the first experimental evidence to show that S. aureus directly utilises sugars present in the ASL for growth. Interestingly, JE2 growth was promoted less by glucose than fructose. Net transepithelial flux of D-glucose was lower than D-fructose. However, uptake of D-glucose was higher than D-fructose across both apical and basolateral membranes consistent with the presence of GLUT1/10 in the airway epithelium. Therefore, we propose that the preferential uptake of glucose (compared to fructose) limits its accumulation in ASL. Pre-treatment with metformin increased transepithelial resistance and reduced the sugar-dependent growth of S. aureus. Thus, epithelial paracellular permeability and glucose transport mechanisms are vital to maintain low glucose concentration in ASL and limit bacterial nutrient sources as a defence against infection

Slavnov-Taylor identities in Coulomb gauge Yang-Mills theory

The Slavnov-Taylor identities of Coulomb gauge Yang-Mills theory are derived from the (standard, second order) functional formalism. It is shown how these identities form closed sets from which one can in principle fully determine the Green's functions involving the temporal component of the gauge field without approximation, given appropriate input.Comment: 20 pages, no figure