The Mod-2 Cohomology Ring of the Third Conway Group is Cohen-Macaulay

By explicit machine computation we obtain the mod-2 cohomology ring of the third Conway group Co_3. It is Cohen-Macaulay, has dimension 4, and is detected on the maximal elementary abelian 2-subgroups.Comment: 12 pages; writing style now more concis

What are the essential components of HIV treatment and care services in low and middle-income countries: an overview by settings and levels of the health system?

OBJECTIVES: To review and summarize the essential components of HIV treatment and care services in low and middle-income countries (LMICs). METHODS: Literature review and reflection on programmatic experience. FINDINGS: There is increasing recognition that the essential 'package' of HIV care must include early identification of HIV-positive people in need of care, appropriate initial and continued counselling, assessment of HIV disease stage, treatment with HAART for those who need it, monitoring while on treatment for efficacy, adherence and side-effects, detection and management of other complications of HIV infection, provision of sexual and reproductive health services as well as careful record-keeping. The impressive scale-up of HIV treatment and care services has required decentralization of service provision linked to task-shifting. But the future holds even greater challenges, as the number of people in need of HIV care continues to rise at a time when many traditional donors and governments in the most-affected regions have reduced budgets. CONCLUSION: In the long-term, the increased demand for HIV-care services can only be satisfied through increased decentralisation to peripheral health units, with the role of each type of unit being appropriate to the human and material resources available to it.HIV-care services can also naturally integrate with the care of chronic noncommunicable diseases and with closely related services like mother and child health, and thus should promote a shift from vertical to integrated programming. Staff training and support around a set of evidence-based policies and guidelines and a reliable supply of essential medicines and supplies are further essential components for a successful programme

Small Business Economics of the Lakota Fund on the Native American Indian Reservation

Poverty rates on Native American Indian reservations are triple the US average. Small business incubation programs, available elsewhere in the US, are sparse on the reservations. Small businesses are potent drivers of US economic growth. Some 25.5 million entrepreneurs generate more than 50% of the GDP, are 26% of the exporters, and create 80% of the total net new job formation. The Small Business Administration (SBA), an independent agency of the federal government created in 1953, maintains and strengthens the nation's economy by aiding, counseling, assisting, and protecting the interests of small businesses and by assisting families and businesses to recover from national disasters. SBA services hardly exist on the Native American Indian Reservations (NAIRs), however. Studies have linked micro entrepreneurial activities to economic growth and poverty reduction. Our study tests the effects of the Lakota Fund (LF), a small business development initiative, on the NAIRs to determine whether SBA-like programs (loans, training, and consulting) can improve economic conditions on the NAIRs. The LF, a private micro loan and business training initiative on the Pine Ridge Reservation in South Dakota, is tested for its effectiveness in generating income. The 1980-2006 annual county-level data (Shannon Co. is 'treatment', Todd Co. is 'control') are a natural experiment; the counties are similar otherwise. Using the real per capita income (RPCI) dependent variable, and controlling for other factors, our regression results indicate that the LF initiative and its duration (intensity) raised RPCI significantly − suggesting the success of a privately funded small business incubation initiative targeted at isolated impoverished groups within the highly developed US economy. Suggestions for future research and program replication ideas are explored.poverty rates, Small Business Administration, Lakota Fund, life expectancy, public sector

Elimination of the reaction rate 'scale effect': application of the Lagrangian reactive particle-tracking method to simulate mixing-limited, field-scale biodegradation at the Schoolcraft (MI, USA) site

This is the peer reviewed version of the following article: [Ding, D., Benson, D. A., Fernàndez‐Garcia, D., Henri, C. V., Hyndman, D. W., Phanikumar, M. S., & Bolster, D. (2017). Elimination of the reaction rate “scale effect”: Application of the Lagrangian reactive particle‐tracking method to simulate mixing‐limited, field‐scale biodegradation at the Schoolcraft (MI, USA) site. Water Resources Research, 53, 10,411–10,432. https://doi.org/10.1002/2017WR021103], which has been published in final form at https://doi.org/10.1002/2017WR021103. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Measured (or empirically fitted) reaction rates at groundwater remediation sites are typically much lower than those found in the same material at the batch or laboratory scale. The reduced rates are commonly attributed to poorer mixing at the larger scales. A variety of methods have been proposed to account for this scaling effect in reactive transport. In this study, we use the Lagrangian particle-tracking and reaction (PTR) method to simulate a field bioremediation experiment at the Schoolcraft, MI site. A denitrifying bacterium, Pseudomonas Stutzeri strain KC (KC), was injected to the aquifer, along with sufficient substrate, to degrade the contaminant, carbon tetrachloride (CT), under anaerobic conditions. The PTR method simulates chemical reactions through probabilistic rules of particle collisions, interactions, and transformations to address the scale effect (lower apparent reaction rates for each level of upscaling, from batch to column to field scale). In contrast to a prior Eulerian reaction model, the PTR method is able to match the field-scale experiment using the rate coefficients obtained from batch experiments.Peer ReviewedPostprint (author's final draft

Miniature Latching Valve

A miniature latching valve has been invented to satisfy a need for an electrically controllable on/off pneumatic valve that is lightweight and compact and remains in the most recently commanded open or closed state when power is not supplied. The valve includes a poppet that is moved into or out of contact with a seat to effect closure or opening, respectively, of the flow path. Motion of the poppet is initiated by electrical heating of one of two opposing pairs of nickel/titanium shape-memory alloy (SMA) wires above their transition temperature: heated wires contract to their remembered length, applying tension to pull the poppet toward or away from the seat. A latch consisting mainly of a bistable Belleville washer (a conical spring) made of a hardened stainless steel operates between two stable positions corresponding to the fully closed or fully open state, holding the poppet in one of these positions when power is not applied to either pair of SMA wires. To obtain maximum actuation force and displacement, the SMA wires must be kept in tension. The mounting fixtures at the ends of the wires must support large tensile stresses without creating stress concentrations that would limit the fatigue lives of the wires. An earlier design provided for each wire to be crimped in a conical opening with a conical steel ferrule that was swaged into the opening to produce a large, uniformly distributed holding force. In a subsequent design, the conical ferrule was replaced with a larger crimped cylindrical ferrule depicted in the figure. A major problem in designing the valve was to protect the SMA wires from a bake-out temperature of 300 C. The problem was solved by incorporating the SMA wires into an actuator module that is inserted into a barrel of the valve body and is held in place by miniature clip rings

The negative side of cohomology for Calabi-Yau categories

We study integer-graded cohomology rings defined over Calabi-Yau categories. We show that the cohomology in negative degree is a trivial extension of the cohomology ring in non-negative degree, provided the latter admits a regular sequence of central elements of length two. In particular, the product of elements of negative degrees are zero. As corollaries we apply this to Tate-Hochschild cohomology rings of symmetric algebras, and to Tate cohomology rings over group algebras. We also prove similar results for Tate cohomology rings over commutative local Gorenstein rings.Comment: 14 page

The Influence of Signaling Conspecific and Heterospecific Neighbors on Eavesdropper Pressure

The study of tradeoffs between the attraction of mates and the attraction of eavesdropping predators and parasites has generally focused on a single species of prey, signaling in isolation. In nature, however, animals often signal from mixed-species aggregations, where interactions with heterospecific group members may be an important mechanism modulating tradeoffs between sexual and natural selection, and thus driving signal evolution. Although studies have shown that conspecific signalers can influence eavesdropper pressure on mating signals, the effects of signaling heterospecifics on eavesdropper pressure, and on the balance between natural and sexual selection, are likely to be different. Here, we review the role of neighboring signalers in mediating changes in eavesdropper pressure, and present a simple model that explores how selection imposed by eavesdropping enemies varies as a function of a signaling aggregation\u27s species composition, the attractiveness of aggregation members to eavesdroppers, and the eavesdroppers\u27 preferences for different member types. This approach can be used to model mixed-species signaling aggregations, as well as same-species aggregations, including those with non-signaling individuals, such as satellites or females. We discuss the implications of our model for the evolution of signal structure, signaling behavior, mixed-species aggregations, and community dynamics