Solving Connectivity Problems Parameterized by Treedepth in Single-Exponential Time and Polynomial Space

A breakthrough result of Cygan et al. (FOCS 2011) showed that connectivity problems parameterized by treewidth can be solved much faster than the previously best known time ?^*(2^{?(twlog tw)}). Using their inspired Cut&Count technique, they obtained ?^*(?^tw) time algorithms for many such problems. Moreover, they proved these running times to be optimal assuming the Strong Exponential-Time Hypothesis. Unfortunately, like other dynamic programming algorithms on tree decompositions, these algorithms also require exponential space, and this is widely believed to be unavoidable. In contrast, for the slightly larger parameter called treedepth, there are already several examples of matching the time bounds obtained for treewidth, but using only polynomial space. Nevertheless, this has remained open for connectivity problems. In the present work, we close this knowledge gap by applying the Cut&Count technique to graphs of small treedepth. While the general idea is unchanged, we have to design novel procedures for counting consistently cut solution candidates using only polynomial space. Concretely, we obtain time ?^*(3^d) and polynomial space for Connected Vertex Cover, Feedback Vertex Set, and Steiner Tree on graphs of treedepth d. Similarly, we obtain time ?^*(4^d) and polynomial space for Connected Dominating Set and Connected Odd Cycle Transversal

After a Flood: Keeping Food Safe

Storm- and flood-damaged foods may not be safe to eat. If you have even the slightest question about the safety of any item, dispose of it

Serving Food Safely in South Dakota’s Great Outdoors

Taking your kitchen into the outdoors is a great adventure. The same safe food handling practices apply in a campground as they do in your kitchen at home. A food-borne illness (often called the stomach flu) can put a damper on your outing

Adding Value to Fruits and Vegetables: Know the Risks

Local growers are looking to expand their customer base; they seek the opportunity to have a greater portion of their revenues derived from “value-added” activity. Value-added activities often involve food processing or the manufacturing of a local commodity (e.g., pickles, jams and jellies, salsa, whole grain breads). Growers considering adding value-added products to their busi¬ness have questions about regulations, as well as about food handling practices that reduce or eliminate possible health and safety risks

Taking Care of Your Nutritional and Physical Needs

When asked what they value most, many people will say their health. However, when faced with a stressful situation that will not go away, the same people forget all about their health and start worrying. Farm and ranch families struggle with extreme stress from uncontrollable forces such as weather, low market prices, or farm machinery breaking down. For many farmers, ranchers, and farm workers, decision making and adjusting to the extraordinary stress consumes their whole thinking, their whole days, their sleepless nights. Their livelihood is dependent upon forces over which they have no control. Eating right and getting adequate amounts of sleep and physical activity are often compromised when faced with crisis situations

Microfield Fluctuations and Spectral Line Shapes in Strongly Coupled Two-Component Plasmas

The spectral line shapes for hydrogen-like heavy ion emitters embedded in strongly correlated two-component electron-ion plasmas are investigated with numerical simulations. For that purpose the microfield fluctuations are calculated by molecular dynamics simulations where short range quantum effects are taken into account by using a regularized Coulomb potential for the electron-ion interaction. The microfield fluctuations are used as input in a numerical solution of the time-dependent Schroedinger equation for the radiating electron. In distinction to the standard impact and quasistatic approximations the method presented here allows to account for the correlations between plasma ions and electrons. The shapes of the Ly-alpha line in Al are investigated in the intermediate regime. The calculations are in good agreement with experiments on the Ly-alpha line in laser generated plasmas.Comment: 5 figure

Organic Production: Practices and Prevalence

In 1995, the United States Department of Agriculture is¬sued the following definition of organic production: Organic agriculture is an ecological production management system that promotes and enhances biodiversity, biological cycles, and soil biologi¬cal activity. It is based on minimal use of off-farm inputs and on management practices that restore, maintain, and enhance ecological harmony

Growing and Direct Marketing Produce: Potential Hazards

Providing a safe food to the consumer requires a process that incorporates food safety from planting to harvesting. Fruit and vegetables growers that market locally are con¬fronted with the same food safety concerns as produce operations that distribute statewide, nationally, or even globally. Growers must first identify the potential food safety hazards related to their operation. Once the hazards are identified, a plan that addresses safe food handling must be implemented

Preparing Turkey for a Crowd: Plan Ahead

This document provides insight on preparing a turkey for a crowd and steps that should be taken before preparing a turkey

Safe Food is Good Business – Cooking Beef Roasts Safely

There are specific requirements for safely cooking beef and corned beef roasts. These requirements vary depending on the size of the roast, the type of oven used, and desired final roast temperatur