High Density

PURPOSE Understanding patterns of left atrial sympathetic activity in healthy individuals and their variation over time. METHODS Ten healthy individuals (4 male, mean age 37.8 (cid:1) 14) un- derwent cardiac computed tomography and 123 I – m IBG isotope nuclear imaging. The two image datasets were merged to generate a detailed anatomical map of cardiac sympathetic innervation. Speci ﬁ c activity (corrected for volume) from each DUA was measured, as as the mediastinal speci ﬁ c activity (corrected for volume), to describe the ratio between DUA and the mediastinum. Nuclear imaging was repeated after 5-7 days, with no apparent change in the subject ’ s con-dition, and compared with baseline imaging. The study was approved by local Ethics Committee and all participants signed informed consent. Mechanisms Ablation AIM 1) to estimate theoretical probability of 4- and 6-waves re-entry to eliminate as a results of linear ablation simulation in 2D-mathe-matical modeling of left atrium (LA); 2) to extrapolate mathematical modeling data to clinical results of linear ablation in patients with paroxysmal and persistent AF. MATERIAL AND METHODS Study was conducted on 40 pts with paroxysmal and persistent AF. First group (paroxysmal) included 20 pts (6 women, 51.4 (cid:1) 13.6 years of age) with paroxysmal AF, who were divided into 2 age-sex-arrhythmia duration subgroups (A and B). The subgroup A consisted of 10 pts in whom ablation strategy consisted of PVI using LASSO approach. The subgroup B concluded of 10 pts in whom ablation strategy consisted of antral isolation of PVs added by roof and mitral isthmus lines. Second group (persistent) concluded 20 pts (6 women, 58.2 (cid:1) 10.6 years of age, duration of arrhythmia – 7.1 (cid:1) 1.1 years) with persistent AF who underwent index circumferential ablation combined with roof and mitral isthmus lines. We evaluated AF CL into the CS during procedure. The numeric reconstruction of the autowave process and the simulation of 4- and 6-wave re-entry AF was performed using Fitzhugh-Nagumo equation. A special scanning method was used for calculating characteristics of autowave processes in 2D mathematical model of LA. Then simulation of circular (corre-sponding to LASSO approach) and linear ablation (corresponding to linear approach) were performed. the 112 (cid:1) (cid:1) ablation. were object of our analysis. 35% were sites of SC: fractionation had low amplitude (0.16 (cid:1) 0.07 mV) and long duration (87.8 (cid:1) 10.7 ms); WFC was seen in 38% of sites with EGMs shorter in duration (46.5 (cid:1) 4.5 ms) and of higher voltage (0.58 (cid:1) 0.13mV); 17% were LB, never responsible for fractionation (0.13 (cid:1) 0.05 mV, 122.4 ms (cid:1) 24.8ms); 9% were PS with high degree of fractionation (0.55 (cid:1) 0.15 mV; 85.8 (cid:1) 7.9ms). Two gaps were identi ﬁ ed (1%) with low degree of fractionation. CONCLUSIONS Speci ﬁ c EGM characteristics can be reproducibly linked to electrophysiological mechanisms. High voltage and short duration EGMs are associated with collision and pivot sites which are unlikely to form critical sites for ablation; long duration, low voltage, EGMs are associated with slow conduction. However, not all slow conduction regions will lie within the critical circuit and identi ﬁ cation by only EGM characteristics cannot guide ablation.

I N THE PAST 30 YEARS, CALIFORNIA'S HOUSING PRICES HAVE STEADILY OUTPACED ITS RESIDENTS' INCOMES. Housing production hasn't kept up with job and household growth within the State. 1 The location and type of new housing does not meet the needs of many new California households. As a result, only one in five households can afford a typical home, overcrowding doubled in the 1990's, and more than three million California households pay more than they can afford for their housing. 2 Meanwhile, the federal government has dramatically cut back programs that used to help local governments accommodate new growth. Voterimposed property tax and spending freezes have further constrained local governments from responding effectively to new growth. And affordable housing development, while still funded in part by the federal government, requires a larger local commitment than ever before.
Against this backdrop, it should surprise no one that many communities no longer accept population growth with open arms. When anyone proposes the development of affordable or multifamily housing, ambivalence about growth often shifts to hostility. Hostility feeds and strengthens certain myths, and deep emotional perceptions of how the world works. Mythsimportant sources of meaning in all societies-provide shared rationales for community members to behave in common ways, having a strong moral component, with clear lines between right and wrong. Although myths are sometimes positive, they can also serve as shields for deeper and uglier motivations: racism, fear of outsiders, and/or greed. When people argue against new high-density and affordable housing, often myths are used to convince decision-makers that the new development and its residents don't belong there. Traffic will be too heavy; schools will become overcrowded; buildings will clash with existing neighborhoods; people won't fit in; and maybe even a criminal element.
Opponents often believe these myths. But it's essential to counter these myths with facts. California desperately needs new affordable housing to reverse recent increases in overcrowding and overpayment. We also need new high-density housing to support economic stability and prosperity. We need housing to accommodate new workers and their families and to economize on infrastructure costs, while preserving open space and reducing the distance between homes and jobs.
Fortunately, the facts of California's recent experiences with high-density and affordable housing often contradict the myths. We can now begin to rely on this recent experience to reassure concerned residents that the myths don't have to come true. 2 T his myth expresses an essential truth: more units per acre mean lower land costs per unit, especially if local governments allow builders meaningful density bonuses; smaller units cost less to build than larger ones. To encourage housing affordability, California cities do need to promote higher densities.
But we also know from experience and observation that not all high-density housing is affordable to low-income families. San Francisco's Nob and Telegraph Hills, Los Angeles' Wilshire Corridor, and high-rises in downtown San Diego are all examples of upper-income areas where housing densities are quite high. Similarly, most Californians know that low-density neighborhoods often accommodate people of modest means. The residents of these neighborhoods often moved in shortly after the homes were built (several decades ago) -and before the huge escalation in California's home values that began in the early 1970's. With assistance, many families with limited incomes will continue to buy homes in these neighborhoods. Many other low-income households will continue to rent single-family homes because they offer more space in low-density neighborhoods.
For the most part, of course, low-density neighborhoods offer more expensive housing than high-density areas. Detached homes cost much more than most apartments and condominiums. Among new units, the difference is even more striking; new high-density units are much more likely to be affordable than new singlefamily units.
Density is not always enough, however. To ensure affordability, local governments must intervene with programs and additional concessions if the new high-density units are also to be affordable. For a list of resources on affordable housing techniques, see Resources: Making Housing More Affordable, at the end of this report. I n California's six largest metropolitan areas, two-thirds of renters and over three-fourths of the households living below the poverty line own no vehicles or only one car, compared to 54 percent of all households and 44 percent of homeowner households. 3 With lower car ownership rates come fewer trips, and fewer single occupant auto commutes. According to the National Personal Transportation Survey in 1995, low-income households make 40 percent fewer trips per household than other households. Recent traffic growth owes much to existing development.
In many high-density neighborhoods, and in most neighborhoods with a mix of housing types, traffic isn't a big problem. Fewer auto trips occur in higher-density areas. In a neighborhood of 15 homes to the acre, one-third fewer auto trips occur, compared to a standard suburban tract. 4 A 1990 survey by the Sierra Club's Transportation Committee found that for every doubling of neighborhood density, vehicle miles traveled are reduced by 20 to 30 percent.
Car ownership rates are less in higher density areas. According to recent American Housing Survey data, multifamily developments have lower car ownership rates than single-family home tracts.

Myth #2
High-density and affordable housing will cause too much traffic.

Fact #2
People who live in affordable housing own fewer cars and drive less.
In many high-density neighborhoods, and in most neighborhoods with a mix of housing types, traffic isn't a big problem.
To encourage housing affordability, California cities need to promote higher densities. High-density housing can encourage nearby retail development, along with ease of walking and transit use. Mixing housing with commercial development is ever more crucial for traffic control, since nonwork trips constitute the largest number of trips.
Over three-fourths of trips in Southern California are non-work trips. With high-density housing, stores serving neighborhood residents move in, allowing residents to walk to buy groceries or to the dry cleaner instead of driving.
Transit connections also become more common when neighborhood density increases, as transit is only cost-effective at densities above eight or 10 units per acre. 5 H igher-density residential development requires less extensive infrastructure networks than does sprawl. California developers must usually pay for sufficient infrastructure capacity to serve their own projects. When communities cannot take advantage economies of scale in providing infrastructure, extension costs rise. High-density housing helps provide economies of scale both in trunk lines and in treatment plants. The cost savings can be passed on to new residents, and the smaller debt load can help ensure fiscal stability throughout the community.
Infill development can sometimes take advantage of unused capacity in public services and infrastructure. Communities can save taxpayers and new residents money when housing construction is allowed in areas where infrastructure and service capacity has already been paid for and is underutilized. Infill development can also make use of a transit and provide better access to services, while improving economic viability.
Higher-density infill residential development can translate to higher retail sales. By approving new highdensity development in infill locations, communities can revitalize stagnant commercial districts and increase taxable sales-the primary source of revenue in most California jurisdictions.
According to the American Housing Survey, the development of single-family homes is much more likely to cause strain on local schools than high-density development. In most cases, a single-family home can have two to three times the numbers of school aged children per household. 6

Myth #3
High-density development strains public services and infrastructure.

Fact #3
Compact development offers greater efficiency in use of public services and infrastructure. A ccording to government definitions of affordable housing, families should devote no more than 30% of their income to rent or mortgage payments and utilities. Affordable housing often means housing whose residents don't pay too large a share of their incomes on rent or a mortgage.
Households earning lower incomes can have a variety of occupational and educational backgrounds. Families earning less than four-fifths (80%) of the area's median income are officially lowerincome households; families earning less than half of the median are known as very low-income households. For example, a starting elementary or high-school teacher in Mountain View (Santa Clara County), with a gross monthly income of around $3,200, can afford to pay $960 a month in rent, which qualifies as low-income if the teacher lives alone; if the salary must support a spouse and a child, the family would be a very low-income household. A starting air-traffic controller in San Diego County, with income barely higher than $31,000 a year, would also qualify for affordable housing. Librarians, sheriffs' deputies, nurses, fire fighters, and many other vital members of our communities all need affordable housing.
People motivated by these concerns may just need to "meet" the residents of high-density and affordable housing. Residents often have been long time members of the community, and will continue to make contributions to their neighborhoods. For a list of resources that can introduce people to those who live in high-density and affordable housing, see Resources: Meeting the Residents of Affordable Housing, at the end of this report.

Myth #4
People who live in high-density and affordable housing won't fit into my neighborhood.

Fact #4
People who need affordable housing already live and work in your community. M any studies have been done. The truth is the single most significant factor affecting property values is the preexisting value of the land in a given community or area. This is turn is based on supply and demand, proximity to major urban centers, nearby attractions (beachfront property, panoramic views), any negative factors such as environmental contaminants, and availability of adequate infrastructure and services.
Architectural standards and adequate maintenance also strongly influence property values, particularly as they apply to affordable rental properties. Properly maintained affordable housing developments, designed and built with sensitivity to the architectural and aesthetic standards desired by the community, may even increase property values. 8 age children, where the mother and father attend PTA meetings, and spend their spare time enjoying parks and other community facilities. These families and other affordable housing tenants are concerned for the public's health and safety just like other residents of the community.

5
A ccording to San Francisco's BRIDGE Housing, annual turnover in their affordable housing projects is less than 10 percent annually. This turnover rate is approximately the same as most single-family homeowners, around 10 > * Source: U.S. Dept. of HUD, American Housing Surveys for San Francisco-Oakland, San Jose, Los Angeles-Long Beach, San Diego, Riverside-San Bernardino, and Anaheim-Santa Ana. _10 unit buildings 2-to 9-unit bldgs.

Owners
Renters moved

Did not move in past year
The majority of both renters and homeowners in California metropolitan areas move less than once a year. Homeowners move less often than renters, but even renters move seldom enough to form long-term ties to neighbors. percent, and much less than marketrate renters.
Affordable housing tenants invest in a neighborhood and community just as much as any other resident. Affordable housing tenants include families with school

Myth #5
Affordable housing reduces property values.

Fact #5
No study in California has ever shown that affordable housing developments reduce property values. 7

Myth #6
Residents of affordable housing move too often to be stable community members.

Fact #6
When rents are guaranteed to remain stable, tenants move less often. Local governments can also help protect the entire community, including new affordable housing residents themselves, by attending to details at the project level. Most important is effective professional onsite management, with strong tenant-screening and good security systems. Design, too, can play an important role in protecting residents and neighbors of high-density or affordable housing, especially by ensuring visibility. New developments should also contain a mix of unit types to accommodate different kinds of households. When residents have different occupations and family types, someone will probably be home in the development almost all the time. D ensity does not cause crime. For many years social scientists have asked whether highdensity housing causes crime. Not one study has shown any relationship between population or housing density and violent crime rates; once residents' incomes are taken into account, the effect of density on non-violent crime decreases to non-significance.

Tenure much more important than density in recent moves
After studying housing and neighborhoods throughout the country, Oscar Newman concluded that the design and use of public spaces, and particularly the sense of ownership and control that residents have over these areas, has far more significant affect on crime than density or income levels.
In neighborhoods suffering from disinvestment, particularly those areas lacking jobs and community services, crime can be higher.
Local governments can help address legitimate concerns about crime by working with existing residents and law enforcement to develop community-based strategies to reduce crime.

Myth #7
High-density and affordable housing undermine community character.

Fact #7
New affordable and high-density housing can always be designed to fit into existing communities.

Myth #8
High-density and affordable housing increase crime.

Fact #8
The design and use of public spaces has a far more significant affect on crime than density or income levels. homes. Thanks to sensitive work by experienced architects, the new townhomes fit in perfectly (see case study). These developments are proof that affordable housing doesn't mean high-rise slums.

In Conclusion
I n this decade, California's persistent affordable housing shortage has become so commonplace that it seems natural. Planners and elected officials must stop believing another pervasive myth: that they can do nothing to create affordable housing. This report shows that many California communities now believe they have the creativity, resources, and will to house all those who need shelter. As a result, they have established that, in fact, California communities can become more open, more accepting, and better places for old-timers, new immigrants, or their children.

High-Density and Affordable Housing Help Balance Silicon Valley
H igh-technology firms create thousands of jobs in Silicon Valley, but housing construction does not keep pace. New workers have to commute long distances to reach their jobs. As a result, Silicon Valley suffers from some of the worst traffic in California and from the State's highest housing prices. In the late 1980s, San Jose set out to clear traffic and ease the housing shortfall by changing its land-use policies. The Renaissance project, on a 56-acre site in north San Jose, was originally designated for research and development. It had enough infrastructure --including a wide road and convenient access to planned light rail to handle a large number of new jobs.
In 1991, Renaissance Associates, a partnership between General Atlantic Development and Forest City Development, proposed with the landowners that San Jose rezone the site for over 1,500 moderate --and high-density rental apartments and for-sale town homes, neighborhood retail, and a day-care center. San Jose readily agreed.
The project developers started work early with neighbors living in an existing single-family development on the site's northern boundary to provide appropriate transitions into Renaissance, while making best use of the large existing road. In response to neighbors' concerns, the developers located the lowest-density town home component adjacent to the existing residences, and provided ample setbacks between the new attached homes & the 1950s-vintage single-family homes.
The developers responded to concerns about traffic by canceling initial plans for a through street that would connect the existing neighborhood with Renaissance Village.
This high-density development shows that often repeated myths about the effects of high-density housing on public services and transportation aren't always true. San Jose's ambitious plans for employment development in the area led the City to require the construction of more infrastructure than was eventually necessary both on the site itself and in neighboring areas of the City. Later, the City determined that it could alleviate traffic throughout its road network by shifting the location of new residences and workplaces.
The composition of the project itself, with over 250 affordable apartments, market-rate apartments, and attached ownership units, further assures balance between the housing and Silicon Valley's new jobs. The site design, which features pedestrian-friendly walkways and easy connections to the Tasman Light Rail, will allow Renaissance Village residents to leave their cars-in their garages altogether.
The development also shows that, with advance planning and sensitivity to neighbors' concerns, NIMBY sentiments can be prevented. The neighbors and the developers displayed an attitude of openness that ensured both a smooth approval process and a better project.

Good Design Beats NIMBYism in Irvine
T he City of Irvine, one of California's largest planned communities, added tens of thousands of new jobs as the information economy boomed. But the City's housing supply-especially housing for families with modest incomes-could not keep up with its job creation. In late 1990s, the City and The Irvine Company, which owns all the undeveloped land in the City, identified a 15-acre multifamily site as appropriate for new affordable housing.
To ensure that such a large and prominent new development would fit into West Park Village, the Irvine neighborhood that surrounds it, The Irvine Company contacted the Costa Mesa-based architecture firm of McLarand Vasquez & Partners (MV&P). MV&P, which had also designed the dense and highly popular Corte Bella town homes across the street from the project site, designed San Paulo's 382 units in 27 separate buildings, with flats and town homes of various sizes. San Paulo's overall density reaches about 25 units per acre, with room left over for two swimming pools, generous landscaping, a tot lot, and numerous features to smooth the transition from San Paulo's surroundings into its highest-density areas.
To show the City's residents that affordable housing and its residents belong in Irvine, The Irvine Company also met early with West Park Village residents. The neighbors were won over by the open process and the high-quality design. The Irvine Company and the City emphasized that San Paulo's residents would be members of the Irvine community. Teachers, firefighters, and other essential contributors to the City's life previously forced out of the City by its high housing prices would find an affordable place to live if San Paulo were approved.
Also key to the project's success was the participation of its non-profit partner, San Francisco's BRIDGE Housing. BRIDGE provided vital advice on affordable housing to the other members of the development team, assisted in the City's approval process, and coordinated the project's financing, which came from City & county sources and State-authorized bonds and tax credits, with credit enhancement by Sumitomo Bank, Ltd. Forty percent of the units are affordable to families earning less than half of Orange County's median income of $56,500; another 50 units are also designated as affordable to low-and moderate-income families.
In Irvine, the developer, architect, non-profit partner, and City staff needed to overcome one key obstacle: unfamiliarity. Residents' preconceptions fit the myths-and not the realityof today's mixed-income, non-profit sponsored affordable housing. By being sensitive to both the design of and nearby a number of boutiques interspersed in a largely residential neighborhood. The School and Church occupied over half of a city block and the Church had rights to the entire block. The bishop was interested in developing housing on the underutilized area of the block. One of the famous Victorian houses succumbed to a fire by transients. The Church had the remains removed and was left with an eyesore and potentially hazardous attraction next to the School playground. Although there are high-rises housing elderly residents in the midtown neighborhood, community members and Saint Francis parishioners didn't perceive an affordable multifamily housing project fitting in to the existing residential neighborhood. There was significant opposition to building such a project.
Mercy Housing California enlisted the assistance of Michael Friedman, an experienced in fill development architect with Tong and Bottomly, to conduct a series of workshops to listen to community and parishioner concerns. To build the desired number of family units composed of one-, two-, and threebedroom units, the architectural firm designed the building from the inside out. Conscientious of local resident concerns, the project saved the School playground while preserving the privacy of the new 46 affordable family housing units. Additionally, local input resulted in new public space for the community to enjoy. The project has been built and occupied for several years and has become an integral part of the midtown neighborhood. Residents and parishioners, who at first feared the project, now point with pride to the community asset they had a hand in creating. 8 surrounding developments and neighboring residents' desires to feel included in decisions, the development team has created a successful model for emulation throughout southern California.

Small Scale, Mixed-Income Housing is good fit for Little Italy Neighborhood Development
T he sloping landscape at the northern downtown edge of San Diego Bay was once home to the many Italian families who derived a living from the highly successful tuna fishing industry. Although large-scale commercial fishing is now a memory, the district's southern European character remains. Always a neighborhood first and then a commercial and light industrial center, Little Italy's spirit is perhaps best typified by the rebuilt Washington Elementary School and development of the adjacent Amici Park, which serves both as a playground for the school and a park including a bocce ball court for the community. Its lovely vistas now offer an urban neighborhood with single-family homes, condominiums, lofts and apartments. The India Street commercial strip is alive with Italian restaurants, small cafes, art and graphic studios/galleries, specialty shops and low-rise offices.
Little Italy Neighborhood Development (LIND), one of the region's most innovative residential

Resources
S ome communities will need to see more specific examples of good high-density and affordable housing before being convinced that they can live with it. In other cases, residents may need to meet people who live in affordable housing. Almost universally, local governments and planners need advice and information about how best to ensure the design of quality affordable and high-density housing in their communities. Luckily, more and more resources--books, pamphlets, handbooks, slide shows, and videos--are becoming available. This list includes only a few resources; those interested are encouraged to contact the California Department of Housing and Community Development (916/445-4728) for ordering information on most of these publications and for additional suggestions.  . This document provides innovative solutions to the challenge of developing higher density housing that will be successful in the marketplace. Case studies of 14 projects show how others have implemented the best new ideas in residential development and design. Projects covered range in density from single-family subdivisions to downtown high-rise apartments and illustrate many up-to-the minute concepts: new urbanism, transit-oriented development, mixed-income and mixed-housing types, urban infill, and adaptive use. They also reveal trends and standards for developing projects that provide a sense of place, use land efficiently without compromising livability, and that can pass the twin tests of governmental approval and marketability. In late 1993, the AIACC will release a follow-up urban design video demonstrating how to respond to community concerns, increase density, encourage mixed-use transit-oriented development, and obtain innovative financing.

Increasing Housing Densities in New and Existing Development
Room Enough. This publication, by San Francisco's Greenbelt Alliance, discusses five strategies using vacant land more effectively, building more housing along major streets, bringing homes and people downtown, adding second units on existing home sites, and recycling lands no longer needed for industry that communities can use to accommodate more housing while meeting concerns about community character and open space. $9. To order, call Greenbelt Alliance at 415/543-4291.

Transit-Oriented, Mixed-Use and Infill Development
Building Livable Communities: A Policymaker's Guide to Infill Development. The January 2001 publication from the Local Government Commission helps to answer two of a policymaker's most frequently asked questions: "Why build in town?" and "What can local government do to encourage infill development?" This guidebook suggests a number of ways to create infill development in your community. These include: planning proactively; assuring public participation; using public facilities and development to attract investment; assisting with project financing; zoning for mixed-use and higherdensity development; encouraging rehabilitation; providing in-kind assistance; streamlining the permit process; providing public services; and addressing toxic contamination.
Building Livable Communities: A Policymaker's Guide to Transit-Oriented Development. This is a companion guidebook on transit-oriented development from the Local Government Commission. More and more, community leaders are recognizing that building residences, stores and work places near transit stops can play a major role in creating places where we enjoy living, working and playing. The guidebook addresses the questions of "why build near transit?" and "why should elected officials, land-use agencies and developers pay more attention to development near transit than to any other kind of development?" The guidebook has helpful advice, model examples, and resources to help create livable, transit-oriented communities in your region.