Cannabis Sustainability Symposium | 2018 Agenda
page-template-default,page,page-id-17068,tribe-no-js,ajax_fade,page_not_loaded,,columns-3,qode-theme-ver-9.1.3,wpb-js-composer js-comp-ver-,vc_responsive

2018 Agenda

Friday, October 26

8:00 – 9:00 AM

Registration & Check-in

Capitol Foyer

Check in for the Symposium

9:00 AM

Welcome and Opening Remarks

Capitol 1-4

Ben Gelt, Board Chair, Cannabis Certification Council

Ben is an entrepreneur and consultant, focused on public affairs and business development. A respected political strategist and policy expert, Ben co-founded the Organic Cannabis Association in 2015. Ben has been at the forefront of cannabis policy in Colorado since 2011, when he worked with the University of Colorado Toxicology Lab to advocate for higher standards of testing in the cannabis industry. He currently serves on the City of Denver Industry Stakeholder Group, The State of Colorado Pesticide Stakeholder Committee and is a principal with Par, LLC. In addition to his efforts in cannabis, Ben works in real estate, public affairs and general business development. Ben lives in Denver, CO.

Andrew Myers, Co-Founder, CEO, ProGrowTech

Andrew Myers is co-founder and CEO of ProGrowTech, which manufactures industry-leading LED lighting that helps commercial horticulture operations increase profitability, yield and energy efficiency. Andrew drives ProGrowTech’s vision, operations, research and product development to expand the company nationwide.

Before founding ProGrowTech with his team in 2015, Andrew spent more than 14 years in state and national politics. As an author of the 2010 Arizona Medical Marijuana Act, he was campaign manager and chief spokesperson for the successful effort to legalize medical marijuana in Arizona. He co-founded the Arizona Medical Marijuana Association and served as Executive Director of the Arizona Dispensaries Association. Andrew’s commitment to innovation hasn’t gone unnoticed – he was recognized in Greenhouse Product News’s 40 Under 40 in 2018.

Andrew previously served as a C-level officer for a defense technology firm and worked for prominent policymakers, including former President Barack Obama and former Secretary of Homeland Security Janet Napolitano.

9:15 – 10:00 AM

Featured Speaker: Sustainability Lessons from the Craft Brewing Industry

Capitol 1-4

John Stier, Sustainability Mentor, Brewer's Association

John Stier is the Principal at Sustainable Brewing Solutions and currently serves as the Sustainability Mentor for the Brewers Association, a not for profit trade organization representing over 4,500 U.S. craft brewers. As the former Director of Corporate Environmental Affairs for Anheuser‐Busch Companies and as a Senior Consultant for The Antea Group, John offers clients more than 35 years of experience with sustainability strategies, water risk management, climate change mitigation and adaptation, regulatory compliance issues and legislative analysis.

During his tenure at Anheuser‐Busch, the company was ranked first in the beverage industry for social and environmental sustainability in FORTUNE magazine’s “America’s Most Admired Companies” and “Global Most Admired Companies.” John partners with clients to develop sustainable strategies that effectively balance financial return, environmental stewardship and social responsibility.

10:15 –  11:30 AM

Free Money: How to Improve Energy Efficiency and Earn Rebates

Looking to upgrade your lighting or HVAC systems to save energy? Don’t leave free money on the table – utility rebate programs can help save on costs, experts will explain how.

Capitol 5

Eric Stern, Co-Founder, Principal, Cultivate Energy Optimization

Eric Stern is a co-founder of Cultivate Energy Optimization and currently serves as a company Principal. At Cultivate, Eric works with utilities and local governments across North America to create and implement new energy efficiency program designs and models to successfully provide resources and rebates to the cannabis cultivation industry. Cultivate currently administers several of the country’s first large-scale cannabis-specific utility energy management programs.
Eric brings 18 years of experience creating and running large-scale utility Demand Side Management programs, with highlighted program experience delivering residential and commercial programs in CA, OK, CO & TX. Prior to forming Cultivate, Eric worked in a variety of national senior management roles for several large implementation firms as well as serving as Colorado’s Residential Buildings Director and State Weatherization Program Director under Governor Ritter in the Colorado Energy Office. Eric holds a BS in Civil and Environmental Engineering from UCLA and an MBA from the Daniels College of Business at the University of Denver.

Mark Crowdis, President & Founder, AgCurrent, Inc.

Mr. Mark Crowdis is a unique entrepreneur. He began his sustainability career in 1986 by starting one of the first certified organic farms in the State of California. Mark transitioned to a focus on energy and climate change while lobbying in Washington, D.C. on Capitol Hill. Mark worked on the U.S. Environmental Protection Agency’s Energy Star Buildings program helping companies identify and engage energy efficiency strategies, products and services. Mark has launched three successful energy businesses, most recently focusing on the development, finance, and installation of energy efficiency, renewable energy and microgrids for North America’s rapidly growing cannabis industry. From leading the development of the U.S. commercial and industrial renewable energy installation market in 1997, to creating a beacon for microgrid installations on Necker Island, Mark has always been a leader in developing markets. Mark has an M.S. in Environmental Science and Policy from Johns Hopkins University and a B.A. in History from the University of California, Davis.

Jacob Schlesinger, Partner, Keyes and Fox

Jake represents some of the nation’s largest providers of clean energy, local governments and customers before utility regulators across the U.S. He advocates for solar, energy storage, energy efficiency and other clean technology policies through regulatory litigation, rulemaking and informal negotiation. Jakes’s practice focuses on grid modernization, project development, demand side management, utility rate design and promoting policies that expand markets for clean energy by fostering competition.

Bob Macauley, Trade Relations Manager, Xcel Energy (Moderator)
Managing Carbon and Air Quality Impacts

Emissions from cannabis operations contribute to significant environmental outcomes. Learn how to reduce your facility’s impact on air quality and climate.

Capitol 6

Angie Fyfe, Executive Director, ICLEI USA

Angie is the Executive Director of ICLEI USA and a member of ICLEI’s global senior management team. Since 1990, ICLEI has built and served a movement of local governments pursuing deep reductions in carbon pollution and tangible improvements in sustainability and resilience. Angie’s previous experience includes serving as the Associate Director of the Colorado Governor’s Energy Office, where she was part of the team to develop and implement 57 pieces of clean energy legislation under Governor Bill Ritter; as the executive director of the U.S. Green Building Council Colorado Chapter; and as a Real Estate Product Manager of global corporate relocation services firm.

Jacob Mitchell, President, Sustainabis
Kaitlin Urso, Environmental Protection Specialist, Small Business Assistance Program, Colorado Department of Public Health and Environment

Kaitlin Urso works as a free environmental consultant for small businesses for the Colorado Department of Public Health and Environment. For 2018-2020, Kaitlin is focusing on providing pro-active environmental assistance to the cannabis industry by furthering research and developing innovative strategies and tools to help assist the cannabis industry in becoming more environmentally friendly.

Janet Burgesser, Program Manager, Denver Department of Public Health & Environment (Moderator)
Controlling Pests and Feeding Plants: Innovative Solutions for Soil and Plant Health

Introducing beneficial microbes and innovative pest control techniques create opportunities for safer, bigger plant growth. Learn how from the experts in this interactive session.

Capitol 7

Amy Tancig-Andrle, Co-Founder, L'Eagle Services (Moderator)
Casey Connell, Owner, Contender Gardens LLC

Casey Connell has been growing medical cannabis for almost 2 decades. He has completed 4 degrees at Oaksterdam University, and extensive courses in controlled environment agriculture. Connell has always placed a high premium on product research and development, concentrating on Bio controls, using and testing beneficial insects with cannabis in an effort to be pesticide free. He also has helped other farmers achieve their integrated pest management (IPM) goals.

Connell started his own cacti farm in Oregon, before moving to Seattle, where he managed his own collective garden. In 2013, Connell founded Contender Gardens LLC, a regulated I-502 producer/processor in Spokane, Wash. Connell is an executive board member of the cannabis farmer’s council in Washington State and speaks frequently about IPM.

Daniel Peck, Entomologist and Biological Program Manager, BioWorks

Dr. Peck is an Entomologist and Biological Program Manager at BioWorks. His technical, research and development efforts are aimed at validating and communicating the science behind biologically-based products for their role in pest management. He worked previously as an Assistant Professor at Cornell, independent turfgrass consultant and international agriculture researcher.

Peter Baas, Director of Research and Development, Growcentia

Dr. Baas currently functions as the Director of R&D for Growcentia where he is involved everything ranging from new product development to product quality control and plant trials. He received his BS and MS from Utrecht University in the Netherlands and his PhD in ecology from the University of Georgia specializing in microbial ecology and biogeochemistry. His postdoctoral research at Colorado State University focused on plant-microbial interactions in agriculture. He has worked in a wide range of ecosystems, ranging from mangroves to agricultural ecosystems, and has an advanced understanding of the interactions and complexities among microbial ecology, nutrient cycling, and plant productivity. As a postdoctoral researcher he was part of the university research team that developed and rigorously tested the product, Mammoth PTM, which resulted in the launch of Growcentia in 2015.

Amy Tancig-Andrle, Co-Founder, L’Eagle Services (Moderator)
High-Tech Cultivation: Maximizing Water and Power Use with Data

New lighting, automation and sensor technologies are changing the way operators grow. Scientists behind these cutting-edge tools will explain how they work, and Jesse Peters will share his experience using them at EcoFirma Farms.

Mineral Hall ABC

Cale Winters, Co-Founder/President, Rhythm Cultivation Solutions & Services

After working in engineering, sales, and marketing roles for some of the world’s largest industrial automation manufacturers, Cale Winters co-founded Rhythm Cultivation Solutions & Services in 2015. Today, Cale serves as President of Rhythm CSS – a horticulture technology company focused on bringing innovative automation solutions, process management and analytics tools, and exceptional service to the cannabis industry.

Dave Spillman, VP Product Development, ProGrowTech
Santosh Balakrishnan, Lush Sensor
Jesse Peters, Founder and CEO, Eco Firma Farm

Jesse Peters is a founder and CEO of Eco Firma Farms, an Oregon OLCC licensed cannabis farm established in 2012.

Mr. Peters earned political credibility in the cannabis space working for over 26 years developing his craft as a cannabis subject matter expert and master cultivator. He is a founding member of the Oregon Cannabis PAC, the Oregon Cannabis Association, a retired Marine, and firefighter. Under Mr. Peters leadership Eco Firma Farms has become one of Oregon’s first carbon-neutral cannabis farm maintaining both environmental and economic sustainability. The farm operates on 100 percent wind-powered renewable energy and uses all organic pest, mold, and mildew management.

Emily Backus, Sustainability Advisor, Denver Department of Public Health & Environment (Moderator)

11:45 AM –  1:00 PM

Grams Per Kilowatt-Hour: Energy Monitoring for Reliable Data

Do you know how much energy you used to grow a pound of flower? Getting accurate energy metrics can be a challenge, but new energy monitoring methods are producing reliable data to help us all better understand the impacts.

Capitol 5

Brad Queen, Mechanical Engineer and Founder, Cube Resources

Brad Queen is a mechanical engineer and the founder of Cube Resources, providing electric load optimization analysis and resource efficiency planning. As the Energy Division Director at the Center for ReSource Conservation he managed the Residential Energy Action Program, the northern Denver Energy Challenge, and the largest sustainable homes tour in Colorado. He created the ReNew Our Schools energy conservation competition. He currently provides interval data analysis and energy modeling services to school districts, solar developers, cannabis cultivation companies, and the Boulder County Energy Impact Offset Fund (BCEIOF).

Joe Sullivan, Head of Grower Partnerships & Energy Technologies, Cultivate Energy Optimization, LLC
Kaitlin Urso, Environmental Protection Specialist, Colorado Department Of Public Health And Environment (Moderator)
Packaging: Creating Efficiencies and Reducing Negative Impacts

The way we think about sustainability, disposable products, and waste recovery needs to evolve. Learn how the cannabis industry can start on the journey to a circular economy by transforming a product with which we all interact – packaging.

Capitol 6

Laura Davis, Public Health Protection Administrator, City & County of Broomfield
Melinda Kadinger, Chief Compliance Officer, Smokey's

Melinda Kadinger is the COO and CFO of Smokey’s – 420 House – an Adult Use and Medical Store and Grow in Garden City and Fort Collins, CO. Melinda has always had a passion for the environment. She has used her personal beliefs to develop and implement productive, sustainable business practices currently in place in their business. Over the past four years Smokey’s has moved towards compostable packaging for self-packaged products as part of the Smokey’s goal of Zero Waste certification. Smokey’s has converted to a full living soil and all-natural growing practices and customer recycle programs resulting in a profitable and responsible model for the cannabis industry.

Sandra Elkind, Chief Creative Officer and Co-Founder, STO Responsible

Sandra Elkind is Co-Founder & Chief Creative Officer of STO Responsible, a Boulder-based sustainable packaging solutions company serving the cannabis industry. She serves as head of product research and development and oversees the marketing of the STO brand.

Sandra brings a deep commitment to environmentalism and a background in conceptual design to STO’s development of sustainable packaging. As a medical marijuana patient herself, she’s experienced firsthand how plant-based medicine can change lives.

Sandra’s design education informs her work at STO Responsible. She holds a bachelor’s in Fine Art Photography and a master’s in Fine Art Photography and Media from Parsons School for Design—The New School. She previously worked as a professor at Colorado State University-Global and Central Texas College.

Reyna Bryan, Director of Strategy and R&D, Elk Packaging

Reyna Bryan is an entrepreneur, inventor and business strategist. She is the Director of R&D for Elk Packaging, a company that specializes fully compostable and recyclable flexible film packaging. Reyna is passionate about material management, circular economy and cultivating innovative solutions that improve the health of people and the planet.

She has a background is in mechanical engineering and engineering management and has worked across several different industries, from energy to aerospace.

Ron Basak-Smith, Co-Founder and CEO, Sana Packaging (Moderator)

Ron Basak-Smith is the Co-Founder and CEO of Sana Packaging, a startup that designs and develops 100% plant-based hemp plastic packaging solutions for the cannabis industry. Ron earned his BA from Ithaca College and his MBA from the University of Colorado Boulder.

Facility Maintenance: Safer, More Effective Cleaning and Waste Disposal

Keeping your facility clean and compliant is a major task. Learn about the new tools and regulatory changes that can help your business maintain sanitation and reduce waste sent to landfills.

Capitol 7

Bobby Zaiatz, Principal, CleneTech Solutions
Kim Stuck, Founder, Allay Consulting

Kimberly Stuck started as a Marijuana Specialist for Denver Department of Public Health and Environment and is now the founder of Allay Consulting LLC. Conducting compliance inspections, licensing assistance, license sign offs, running pesticide investigations, writing press releases, conducting recalls, conducting shelf stability and CBD source approvals, she’s done it all. She has disposed of millions of dollars of Cannabis/ Cannabis products during her government career due to non-compliance. She has greatly helped Colorado develop requirements and has also helped California Department of Public Health (CDPH) develop their regulations. She has knowledge of local, state and federal cannabis and health regulations in several legal states. During the years as a regulator she grew a love for the industry and the people in it. She knew she could make a huge difference and save Cannabis companies millions through active preventative measures if she started her own company. Kim has worked hand in hand with other regulatory agencies including the Marijuana Enforcement Division, the local fire departments, Colorado Department of Agriculture, CDPHE, Plan Review, Excise and license department, and building departments.

Garrett Rodewald, COO, Gaiaca

Garrett hails from Pacific Grove, California and has an extensive science background and over a decade of experience in environmental consulting specializing in industrial hygiene and EPA & OSHA compliance. He earned his B.S. from the University of California, Santa Cruz, in Ecology and Evolutionary Biology.

Cindy Sovine, President & CEO, Sovine Consulting

Cindy has over 18 years of government relations experience in Colorado working on local, state and federal issues. She is highly effective at helping clients achieve their goals and successfully navigate ever-changing legislative, regulatory and political environments. She is a Colorado native who grew up farming and ranching in eastern Colorado. Cindy spent much of her career working in health care and early childhood education until she began working in cannabis policy in 2016 after her step-dad’s journey with lymphatic cancer and seeing firsthand how cannabis alleviated his suffering and provided a quality of life that traditional treatments could not provide. Cindy is seeking to move the needle forward on Cannabis policy by opening a social use holistic wellness spa and member lounge that allows on sight consumption, THC and CBD massage and more.

Legislative Experience
Cindy began her career in the Office of Legislative Council, the Colorado General Assembly’s non-partisan staff, where she learned the rules and legislative process inside and out. She worked with staff on the health and human services committees and coordinated the state’s ballot initiative process. Cindy made the switch to lobbying in 2003, working as the Government Affairs Director for the Colorado Hospital Association. She worked for a major Denver lobbying firm representing a large portfolio of clients and subsequently started her own company in 2006 as an independent government affairs Consultant. Cindy’s lobbying experience in health care includes nearly every industry within the health care delivery system including hospitals, insurance companies, pharmaceuticals, providers and more. In addition to cannabis, Cindy works in early childhood education, agriculture, and business development and procurement for companies seeking to do business with the State and its local governments.

Regulatory Experience
The regulatory arena has a far bigger role in determining public policy than many realize. Throughout her career Cindy has worked to influence issues in the regulatory arena, successfully ushering her clients’ interests through the process. She helps industries raise their credibility while helping her clients develop successful working relationships with regulators. She maintains connections with all state agencies but works frequently with the Departments of Revenue, Regulatory Agencies, Health Care Policy and Financing, Public Health and Environment, and Human Services. She has helped create regulatory infrastructures for multiple industries and has also helped her clients by initiating rule changes, re-writes and revisions, as well as repeatedly overturning regulations, either within the administration itself, or ultimately through legislative mandate.

Growing with Sunlight

What’s the best method of harnessing the sun’s power to grow cannabis? Experts in outdoor cultivation, greenhouses, and indoor cultivation with Solatubes will engage in a lively debate for you to judge.

Mineral Hall ABC

Josh Holleb, Project Manager / Sales Engineer, Ceres Greenhouse Solutions
Rob Trotter, Owner, Pot Zero
Kayvan Khalatbari, Founding Partner, Denver Relief Consulting (Moderator)

1:00 – 2:00 PM


Capitol 1-4

2:00 – 3:00 PM

Today’s Energy Policy Landscape: Implications for the Cannabis Industry (Keynote)

With ambitious energy and sustainability goals to fulfill, regulators are increasingly taking action to constrain the energy impacts of the cannabis industry. Learn about the latest programs in Colorado and Massachusets and how they could impact your business.

Capitol 1-4

Derek Smith, Executive Director, Resource Innovation

Derek Smith is Executive Director and Co-Founder of Resource Innovation Institute (RII), a national non-profit whose mission is to promote and quantify energy, carbon and water conservation in the cannabis industry. Prior to RII, Mr. Smith ran Clean Energy Works, a residential energy efficiency program that blended utility, public and private dollars to deliver whole-building retrofits while generating carbon emission reductions along with equitable economic development outcomes. Clean Energy Works was hailed as one of the most successful US Dept. of Energy funded stimulus programs in the country. Mr. Smith has also led energy programs with the City of Portland Bureau of Planning & Sustainability, served on the management team of a Zero VOC start-up paint company and developed an award-winning corporate sustainability program for a national retailer.

Brad Smith, Sustainability Outreach Specialist, Boulder County

Brad Smith is a sustainability specialist for Boulder County helping to build, operate, and communicate Boulder County sustainability services. He manages the Boulder County Energy Impact Offset Fund working with marijuana cultivators to offset their high energy intensity through energy efficiency, renewable energy, policy, and other offset projects.

Michael Turner, Director of Commercial and Industrial Energy Services, Colorado Energy Office

Michael Turner is the Director of Commercial and Industrial Energy Services at the Colorado Energy Office. He is responsible for designing, implementing, and communicating program and policy initiatives created to ensure Colorado’s commercial and industrial energy consumers have access to cost-effective energy efficiency and renewable energy. He holds an MA in Energy Policy from Columbia University, received his BA in Economics from the Colorado College, and is from Denver, Colorado.

Ben Gelt, Board Chair, Cannabis Certification Council (Moderator)

3:15 PM –  4:30 PM

Alternative Energy Options

This session will explore opportunities to improve your business’ carbon footprint through renewable and alternative energy sources, while taking a practical approach to the unique needs of the cannabis industry.

Capitol 5

Brandon Welch, Colorado Carbon Fund Managing Director, Natural Capitalism Solutions

Brandon is interested in reinventing the carbon economy by connecting people and private capital with food, fiber, and land. He is enabling this through scaling regenerative agriculture to sequester carbon, improve water quality and quantity, growing healthier food, and making the producer more money.

Charlie Wilde, Solar Energy and EV Advocate, Ecology Solar

Charlie Wilde’s “Big Why” in life is the preservation and restoration of earth’s natural ecosystems. He believes fervently that solar energy is a far better source for energy than fossil
fuels. Charlie is a solar + EV enthusiast, public speaker, and team leader at Ecology Solar in Denver.

John Shaw, Commercial Solar Project Developer, Namaste Solar

John Shaw entered solar in 2006. PV design & installation certified by SEI. NABCEP certified in PV Technical Sales. 3 years representing an American commercial inverter manufacturer. Molding life events: backpacking a month in Wyoming, travelling from Nassau, Bahamas to Seattle, WA by ship, the long way and living in Japan 3 years.

Tom Hawes, Executive Sales Director, Centrica Business Solutions

Tom Hawes is an executive sales director at Centrica Business Solutions where he has been tasked with leading the Industrial, Agriculture and Manufacturing vertical for North America. Previously, his focus was on developing Microgrid, Central plant and Renewable Energy projects for enterprise accounts in the Midwest marketplace. Hawes has over 20 years of diverse experience in the energy industry, including roles at Edison Energy and NRG Energy.

Jacob Mitchell, President, Sustainabis (Moderator)
Mastering Your Mechanical System for Optimal Growth

Environmental control is one of the biggest concerns for any cannabis cultivation operation. Learn how to increase product consistency and quality while maximizing your HVAC system’s efficiency.

Capitol 6

Brandy Keen, Co-Founder and Senior Technical Advisor, Surna
Devin Cooley, President & COO, SunTrac USA

Devin Cooley is the Co-Founder, President & COO of SunTrac USA, a renewable-tech manufacturer in the HVAC industry. SunTrac’s Hybrid Climate Systems create energy savings of 25% to 40% for commercial and industrial air conditioning systems.

Devin has spent the past 7 years cultivating relationships in both the renewable energy and HVAC industries with OEM’s and channel partners. Devin is a graduate of the University Washington, and has a Pit-Bull Dalmatian named Leonitus.

Stephen Keen, Owner, Sterling Pharms
Ricardo Baca, Founder & CEO, Grasslands (Moderator)
Extraction: Understanding and Controlling Environmental Concerns

Extraction equipment and infused product manufacturing present environmental challenges unique from other cannabis businesses. Experts in extraction management and equipment will explain how to prevent costly environmental and safety mistakes.

Capitol 7

Thuy Vu, Founder and CEO, Thuy Vu Consulting
Eric Vlosky, Director of Marketing, PurePressure

Eric Vlosky is the Director of Marketing at PurePressure, which has been instrumental in evolving the rosin industry into a common commercial processing method. With almost a decade of leadership experience and 4 years of cannabis industry work under his belt, Eric is actively involved with world class solventless processors.

Alex Thompson, National Licensing Specialist, Vicente Sederberg
Andrew Livingston, Director of Economics & Research, Vicente Sederberg (Moderator)
How Corporate Social Responsibility in Cannabis Can Repair Harms of the War on Drugs

How can cannabis businesses contribute to sustainability, community engagement, and repair? This panel will consider those questions and dig into recent examples of success and failure in the world of cannabis CSR.

Mineral Hall ABC

Adam Vine, Co-Founder, Cage Free Cannabis

Adam Vine co-founded Cage-Free Cannabis to help the cannabis industry and its consumers repair harms of the War on Drugs and create an equitable cannabis economy. This project emerges from a career at the intersection of social justice, media, and politics. Adam lives and works in Los Angeles, California.

Kelly Perez, CEO/Founder, kindColorado, LLC (kindCO)

Kelly Perez is the CEO/founder of kindColorado, LLC (kindCO). We are a social venture dedicated to equity and justice focused, conscious community-cannabis partnerships can improve the health of communities, and help to shift the cannabis narrative towards positive impact.

Betty Aldworth, Executive Director, Students for Sensible Drug Policy
Marc Ross, Chief Instigator, Needle Consultants (Moderator)

Marc Ross is the Chief Instigator for Needle Consultants, LLC, a Corporate Social Responsibility firm whose work includes building purposeful brands within the cannabis and hemp industries. Marc is a 25-year attorney who has worked in the public, private, and nonprofit sectors, most recently as the founder and Executive Director to Rock the Earth, an environmental advocacy organization that works with the music industry to protect some of the world’s most threatened places.

4:45 – 6:30 PM

Closing Reception

Capitol 1-4